Single coating type UV and heat dual-curing laser anti-counterfeiting coating and UV mold pressing microstructure copying process

Abstract

The invention provides a single coating type UV (ultraviolet) and heat dual-curing laser anti-counterfeiting coating and a UV mould pressing microstructure copying process. The coating is prepared from the following raw materials in parts by weight: 50 to 70 parts of film-forming resin, 15 to 30 parts of reactive diluent, 2.5 to 4.3 parts of photoinitiator, 5 to 8 parts of blocked isocyanate, 3 to 6 parts of core-shell structured polysiloxane elastic microspheres, 4 to 7 parts of nano titanium dioxide-acrylate hybrid, 0.3 to 0.6 part of organic silicon flatting agent, 0.2 to 0.5 part of acrylate defoaming agent and 8 to 16 parts of propylene glycol methyl ether acetate. The anti-counterfeiting coating disclosed by the invention can form a compact and uniform cross-linked cured film, and has excellent temperature resistance, solvent resistance and flexibility, the laser microstructure size stability is good, and the optical performance and wear resistance can meet the technical requirements of laser anti-counterfeiting application.

Description

Technical Field

[0001] This invention relates to the field of anti-counterfeiting coating technology, specifically to a single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating and a UV molding microstructure replication process. Background Technology

[0002] Laser anti-counterfeiting coatings rely on specific optical microstructures on the coating surface to achieve anti-counterfeiting functions. They possess the technical characteristics of high recognition and difficulty in counterfeiting, and are widely used in packaging, document identification, and other fields. Their performance is closely related to the curing method and the microstructure replication effect. In the existing technology, the curing systems of laser anti-counterfeiting coatings are mainly divided into three categories: UV curing, thermal curing, and dual curing. Among them, the UV curing system has high curing efficiency and can quickly form laser microstructures, but the cross-linking density is limited, and the coating's temperature resistance and solvent resistance are insufficient. Thermosetting systems can form a dense cross-linking network, improving the mechanical properties of the coating, but they suffer from long curing cycles and low production efficiency. Although some dual-curing coatings combine the advantages of UV curing and thermal curing, they mostly adopt multi-coat processes, which have technical defects such as cumbersome process steps, weak interfacial bonding between coatings, and high production costs.

[0003] Existing dual-curing laser anti-counterfeiting coatings, using a single-coat process, struggle to achieve a balance between high-density cross-linked network construction and stress control during curing. Simply pursuing increased cross-linking density leads to decreased coating flexibility, causing the laser microstructure to warp and deform during curing or subsequent use, severely impacting the accuracy and stability of the anti-counterfeiting pattern. Furthermore, existing coatings exhibit poor synergy between optical and abrasion resistance properties, resulting in decreased laser pattern recognizability due to wear and aging over long-term use, failing to meet the requirements for long-term anti-counterfeiting applications. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a single-coat UV and thermal dual-curing laser anti-counterfeiting coating and a UV molding microstructure replication process.

[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention discloses a single-coat UV and thermal dual-curing laser anti-counterfeiting coating. By weight, its raw materials include: 50-70 parts of film-forming resin, 15-30 parts of reactive diluent, 2.5-4.3 parts of photoinitiator, 5-8 parts of blocked isocyanate, 3-6 parts of core-shell structured polysiloxane elastic microspheres, 4-7 parts of nano-titanium dioxide-acrylate hybrid, 0.3-0.6 parts of silicone leveling agent, 0.2-0.5 parts of acrylate defoamer, and 8-16 parts of propylene glycol methyl ether acetate.

[0006] Using the above technical solution, the film-forming resin provides the film-forming basis for the coating, the reactive diluent adjusts the viscosity of the system and participates in the crosslinking reaction, and the photoinitiator can initiate the UV curing process, promoting the formation of a preliminary crosslinking network in the coating. After the blocked isocyanate is unblocked during the heat curing stage, it can react with the active groups in the resin to form a high-density crosslinking network, improving the coating's temperature resistance and solvent resistance. The methacryloyloxy group in the shell of the core-shell structured polysiloxane elastic microspheres can participate in the UV curing reaction, forming a chemical bond with the resin matrix, preventing the microspheres from agglomerating in the coating, and ensuring uniform stress dissipation. The nano-titanium dioxide-acrylate hybrid can improve the compatibility with the coating matrix, while enhancing the coating's optical properties and abrasion resistance. The organosilicon leveling agent can optimize the coating surface condition and improve the coating smoothness. The acrylate defoamer can reduce the generation of bubbles during the coating process and reduce coating defects. Propylene glycol methyl ether acetate, as a solvent, ensures the uniform dispersion of each component and improves the coating film quality.

[0007] Preferably, the film-forming resin comprises 35-45 parts of hyperbranched polyurethane acrylate and 15-25 parts of hydroxyl-containing polyester acrylate; the reactive diluent comprises 10-20 parts of ethoxylated trimethylolpropane triacrylate and 5-10 parts of dicyclopentadiene diacrylate; the photoinitiator comprises 1.5-2.5 parts of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and 1.0-1.8 parts of ethyl 2,4,6-trimethylbenzoylphenylphosphonate, and the hydroxyl-containing polyester acrylate is hydroxyl polyethylene glycol acrylate.

[0008] Using the above technical solution, hyperbranched polyurethane acrylate provides a large number of reactive end groups for the coating, ensuring rapid UV crosslinking. Its low viscosity optimizes workability, and the intramolecular cavity can absorb some of the curing stress. The hydroxyl groups in hydroxyl polyethylene glycol acrylate react with the blocked isocyanate thermosetting agent to form a polyurethane crosslinking network, and the ether bonds in the polyethylene glycol segments form hydrogen bonds with the hyperbranched polyurethane acrylate. Ethoxylated trimethylolpropane triacrylate provides crosslinking points, and the ethoxylated segments improve the coating's flexibility and reduce shrinkage stress. The ether bonds in the molecule enhance compatibility with the resin. The rigid bicyclic structure of dicyclopentadiene diacrylate enhances laser diffraction efficiency while reducing volume shrinkage and participates in the formation of a high-density crosslinking network. Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide absorbs long-wave UV to achieve deep curing of the coating, while ethyl 2,4,6-trimethylbenzoylphenylphosphonate absorbs short-wave UV to achieve rapid surface curing. The two work together to ensure uniform curing of the coating and avoid over-curing of the surface while insufficient curing of the interior.

[0009] Preferably, the raw materials for preparing the core-shell structured polysiloxane elastic microspheres, by weight, include: 10-15 parts of octamethylcyclotetrasiloxane, 0.5-1.0 parts of tetramethyltetravinylcyclotetrasiloxane, 0.3-0.6 parts of tetramethylammonium hydroxide, 3.0-4.5 parts of methyltrimethoxysilane, 1-2 parts of γ-methacryloyloxypropyltrimethoxysilane, 80-100 parts of anhydrous ethanol, and 0.5-1.0 parts of sodium dodecyl sulfate.

[0010] Using the above technical solution, octamethylcyclotetrasiloxane provides the basic polysiloxane structure for the core layer of the core-shell polysiloxane elastic microspheres; tetramethyltetravinylcyclotetrasiloxane, as a comonomer, introduces vinyl active sites to promote the formation of the core layer structure; tetramethylammonium hydroxide catalyzes the ring-opening polymerization reaction of cyclosiloxane, promoting the smooth synthesis of the core layer; methyltrimethoxysilane participates in the shell layer hydrolysis and condensation reaction to construct the silicone resin shell framework; γ-methacryloyloxypropyltrimethoxysilane endows the shell layer with acrylate functional groups, enabling the core-shell polysiloxane elastic microspheres to chemically bond with the resin in the coating system; anhydrous ethanol serves as a dispersion medium to ensure uniform dispersion of each reactant and maintain the stability of the reaction system; sodium dodecyl sulfate plays an emulsifying role, promoting the formation of a stable emulsion and helping to control the uniformity of the particle size of the core-shell polysiloxane elastic microspheres.

[0011] Preferably, the preparation method of core-shell structured polysiloxane elastic microspheres includes the following steps: 1) Add octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, anhydrous ethanol, and sodium dodecyl sulfate to a reaction vessel and mix at 180-220 r / min for 15-20 min. Slowly add tetramethylammonium hydroxide and maintain a stirring rate of 300-350 r / min. Under nitrogen protection at a flow rate of 0.1-0.2 L / min, raise the temperature to 85-95℃ and continue stirring for 5-7 h to obtain a vinyl-containing polysiloxane elastic microsphere emulsion. 2) Cool the vinyl-containing polysiloxane elastic microsphere emulsion to 60-70℃, add methyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane sequentially, mix at 180-220 r / min for 15-20 min, then adjust the pH of the system to 4.5-5.5 with 0.5-1.0 mol / L acetic acid aqueous solution, and stir the reaction at 240-260 r / min for 4-6 h; 3) Centrifuge the reaction solution obtained in step 2) at 6000-8000 r / min for 10-15 min. Wash the precipitate obtained by centrifugation with anhydrous ethanol 3-4 times. After each washing, centrifuge the precipitate under the same conditions. Dry the precipitate under a vacuum of -0.080 MPa to -0.095 MPa and a temperature of 55-65℃ for 8-12 h to obtain core-shell structured polysiloxane elastic microspheres.

[0012] Using the above technical solution, a vinyl-containing polysiloxane elastic microsphere emulsion is formed through mixing and stirring of various raw materials and heating reaction under nitrogen protection, providing a basis for the core-shell structure. Subsequently, methyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane are added and the pH of the system is adjusted to form an acrylate-functionalized shell on the surface of the microspheres. After centrifugation, washing with anhydrous ethanol and vacuum drying, pure core-shell structured polysiloxane elastic microspheres are obtained. The acrylate functional groups on their surface can chemically bond with the resin in the coating system, which helps to improve the internal stress dispersion ability and microstructure stability of the coating.

[0013] Preferably, the raw materials for preparing the nano-titanium dioxide-acrylate hybrid, by weight, include: 10-15 parts nano-titanium dioxide, 2.5-3.5 parts γ-methacryloyloxypropyltrimethoxysilane, 5-7 parts hydroxyethyl acrylate, 0.1-0.2 parts p-hydroxyanisole, 0.3-0.5 parts tetrabutyl titanate, 80-100 parts anhydrous ethanol, and 0.05-0.1 parts hydroquinone.

[0014] Using the above technical solution, nano-titanium dioxide provides a high refractive index basis for the hybrid; γ-methacryloyloxypropyltrimethoxysilane modifies the surface of nano-titanium dioxide, introducing reactive functional groups; hydroxyethyl acrylate participates in the grafting reaction, creating conditions for the chemical bonding between the hybrid and the coating system; p-hydroxyanisole and hydroquinone play a polymerization inhibitory role, suppressing unnecessary polymerization reactions during the preparation process; tetrabutyl titanate catalyzes the smooth progress of surface modification and grafting reactions; anhydrous ethanol is used as a dispersion medium to ensure uniform dispersion of each raw material, promoting the formation of a structurally stable nano-titanium dioxide-acrylate hybrid, which can improve the optical properties, interfacial compatibility, and wear resistance of the coating.

[0015] Preferably, the preparation method of the nano-titanium dioxide-acrylate hybrid includes the following steps: (1) Under light-protected conditions, nano-titanium dioxide with an average particle size of 30-50 nm was dispersed in anhydrous ethanol and treated for 30-45 min under ultrasonic power of 300-400 W and frequency of 35-45 kHz to obtain nano-titanium dioxide suspension. (2) Under light-protected conditions, add γ-methacryloxypropyltrimethoxysilane and hydroquinone to the nano-titanium dioxide suspension, stir at 400-500 r / min for 15-20 min, adjust the pH of the system to 4.5-5.5 with 0.5-1.0 mol / L acetic acid aqueous solution, heat the system to 70-80℃ under nitrogen protection at a flow rate of 0.1-0.2 L / min, and stir the reaction at 400-500 r / min for 6-8 h; (3) In a nitrogen atmosphere at a flow rate of 0.1-0.2 L / min, hydroxyethyl acrylate, p-hydroxyanisole and tetrabutyl titanate are added to the system obtained in step (2), and stirred at 400-500 r / min for 15-20 min. The temperature is raised to 80-85℃, and the reaction is carried out at this temperature and stirring speed for 4-5 h. (4) Centrifuge the system obtained in step (3) at 8000-10000 r / min for 8-10 min. Wash the precipitate obtained by centrifugation with anhydrous ethanol 3-4 times. After each washing, centrifuge the precipitate under the same conditions. Dry the precipitate under vacuum of -0.080 MPa to -0.095 MPa and temperature of 55-65℃ for 8-12 h to obtain nano-titanium dioxide-acrylate hybrid.

[0016] Using the above technical solution, nano-titanium dioxide is uniformly dispersed in anhydrous ethanol through ultrasonic treatment; light-proof and nitrogen-protected conditions ensure the stability of each component during the preparation process; the pH is adjusted to 4.5-5.5 to provide an optimal acidic environment for the hydrolysis of γ-methacryloyloxypropyltrimethoxysilane, promoting the condensation reaction between the silane coupling agent and the hydroxyl groups on the surface of nano-titanium dioxide, and introducing reactive functional groups; hydroquinone and p-hydroxyanisole play a polymerization inhibitory role, and tetrabutyl titanate catalyzes the surface modification and acrylate grafting reaction; after centrifugation, washing with anhydrous ethanol and vacuum drying, impurities are removed and a pure nano-titanium dioxide-acrylate hybrid is obtained.

[0017] Preferably, the preparation method of the anti-counterfeiting coating includes the following steps: a. Add hyperbranched polyurethane acrylate, hydroxyl-containing polyester acrylate, and propylene glycol methyl ether acetate to a dispersion vessel and mix for 15-20 min at 600-800 r / min and 25-35℃. b. Add ethoxylated trimethylolpropane triacrylate, dicyclopentadiene diacrylate and nano-titanium dioxide-acrylate hybrid to the system obtained in step a, and disperse for 30-40 min at 600-800 r / min and 40-50℃. c. Add silicone leveling agent and acrylate defoamer to the system obtained in step b, and stir for 10-15 minutes at 400-600 r / min and 30-40℃. d. Under light-protected conditions, add phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and ethyl 2,4,6-trimethylbenzoylphenylphosphonate to the system obtained in step c, and stir for 8-12 min at 400-600 r / min and 30-40℃. e. Under light-protected conditions, add blocked isocyanate and core-shell structured polysiloxane elastic microspheres to the system obtained in step d. Stir for 5-8 minutes at 200-300 r / min and 30-40℃. Filter the resulting reaction solution through a 260-300 mesh stainless steel filter at a filtration pressure of 0.1-0.2 MPa. After collecting the filtrate, seal it in a light-protected container to obtain a single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating.

[0018] Using the above technical solution, the components are gradually mixed and dispersed in sequence under corresponding stirring rates and temperature conditions, so that the hyperbranched polyurethane acrylate and hydroxyl-containing polyester acrylate are fully dissolved; ethoxylated trimethylolpropane triacrylate, dicyclopentadiene diacrylate and nano-titanium dioxide-acrylate hybrid are uniformly dispersed without agglomeration; the organosilicon leveling agent and acrylate defoamer are fully integrated to optimize the surface properties of the coating; light-protected operation can ensure the stability of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and ethyl 2,4,6-trimethylbenzoylphenylphosphonate; low-speed stirring protects the structural integrity of the core-shell structured polysiloxane elastic microspheres; and the closed isocyanate is uniformly dispersed in the system; finally, after filtration to remove impurities and sealing in light-protected packaging, a single-coat UV and thermal dual-curing laser anti-counterfeiting coating with uniform components and stable state is obtained, which provides a guarantee for the subsequent accurate replication of the microstructure of the coating and excellent optical, mechanical and durability properties.

[0019] This invention also discloses a UV molding microstructure replication process, which utilizes the aforementioned single-coat UV and thermal dual-curing laser anti-counterfeiting coating, and includes the following steps: S1. Coating: Apply the single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating onto the corona-treated biaxially oriented polyester film. The wet film thickness is controlled at 12-18μm and the coating speed is 20-30m / min. S2, UV pre-crosslinking: using a wavelength of 365-395nm and a power density of 60-90mW / cm² 2 The wet film obtained in step S1 is irradiated with an LED lamp for 7-11 seconds to perform a pre-crosslinking treatment, resulting in a double bond conversion rate of 35%-45%. S3, Hot embossing: Hot embossing is performed immediately after UV pre-crosslinking, using a laser nickel plate at a temperature of 90-110℃ and a pressure of 0.4-0.6MPa for 3-5 seconds; S4. Heat curing: The film material imprinted in step S3 is placed in a hot air drying tunnel at 130-140℃ and kept warm for 15-20 minutes. S5. Photocuring Enhancement: Utilizing a dominant wavelength of 355-375nm and a power density of 800-1000mW / cm². 2 The membrane material treated in step S4 was irradiated with a mercury lamp for 5-8 seconds. S6. Gradient peeling: Cool the film material treated in step S5 to 35-45℃, peel off the laser nickel plate at a peeling angle of 30-45° and a speed of 5-10m / min to obtain the laser transfer film.

[0020] Using the above technical solution, the coating forms a uniform wet film on the corona-treated biaxially oriented polyester film, providing a stable substrate for microstructure replication. UV pre-crosslinking forms a preliminary crosslinking network through irradiation with a specific wavelength LED lamp, while retaining the thermoplasticity of the coating, creating conditions for the complete transfer of microstructures during hot embossing. The temperature of 90-110℃ matches the glass transition temperature (Tg=50-70℃) of the pre-crosslinked coating, allowing the coating to flow rapidly under pressure and replicate the microstructure without degradation due to excessive temperature. During hot embossing, the temperature and pressure of the laser nickel plate work synergistically to accurately replicate the microstructure onto the coating. The thermal curing stage promotes the unsealing of blocked isocyanates and their reaction with resin hydroxyl groups, improving the crosslinking density and temperature resistance of the coating. Photocuring enhancement achieves high conversion rate of acrylate double bonds through deep curing with a mercury lamp, improving the surface hardness of the coating. Gradient peeling is performed at appropriate temperature, angle, and speed to avoid damage to the microstructure, ultimately obtaining a laser transfer film with high microstructure fidelity and balanced mechanical and durability properties.

[0021] Preferably, in step S1, the thickness of the biaxially oriented polyester film is 12-16 μm, and the light transmittance is ≥90%.

[0022] Using the above technical solution, a 12-16μm thick biaxially oriented polyester film provides stable support for the coating, ensuring the dimensional stability of the film material in subsequent processes such as coating and hot stamping; a transmittance of ≥90% allows UV light to fully penetrate into the coating, ensuring uniform curing reaction during the UV pre-crosslinking and photocuring enhancement stages, and providing a guarantee for high-fidelity replication of microstructures and optimization of the coating's mechanical and optical properties.

[0023] Preferably, in step S1, the surface dyne value of the corona-treated biaxially oriented polyester film is 40-42 mN / m.

[0024] By adopting the above technical solution, the wettability of the film surface can be improved, so that the single-coat UV and heat-cured laser anti-counterfeiting coating can be evenly spread on its surface to form a continuous and flat wet film; at the same time, the interfacial bonding between the coating and the film can be enhanced, the coating adhesion can be improved, and the bonding stability between the coating and the substrate can be ensured in subsequent process steps.

[0025] The beneficial effects of this invention are as follows: Film-forming resins provide the foundation for film formation, reactive diluents adjust the viscosity of the system and participate in crosslinking reactions, and photoinitiators can initiate the UV curing process, promoting the formation of a preliminary crosslinking network in the coating. After being unsealed during the thermosetting stage, blocked isocyanates can react with the active groups in the resin to form a high-density crosslinking network, improving the coating's temperature resistance and solvent resistance. Core-shell structured polysiloxane elastic microspheres can participate in the crosslinking process through surface functional groups, and their core elastic structure can absorb the volume shrinkage stress generated during curing, reducing internal stress during curing and improving the coating's flexibility and microstructure stability. Nano-titanium dioxide-acrylate hybrids can improve compatibility with the coating matrix while enhancing the coating's optical properties and abrasion resistance. Organosilicon leveling agents can optimize the coating surface condition and improve coating smoothness. Acrylic defoamers can reduce the generation of bubbles during coating and reduce coating defects. Propylene glycol methyl ether acetate, as a solvent, ensures uniform dispersion of each component and improves the quality of the coating film. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Specific information on the raw materials used in the embodiments of this invention is shown in Table 1: Table 1. Raw material names and sources

[0028] Example 1: This embodiment discloses a single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating. By weight, its raw materials include: 35 parts hyperbranched polyurethane acrylate, 15 parts hydroxyl-containing polyester acrylate, 10 parts ethoxylated trimethylolpropane triacrylate, 5 parts dicyclopentadiene diacrylate, 1.5 parts phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 1 part ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 5 parts blocked isocyanate, 3 parts core-shell structured polysiloxane elastic microspheres, 4 parts nano-titanium dioxide-acrylate hybrid, 0.3 parts silicone leveling agent, 0.2 parts acrylate defoamer, and 8 parts propylene glycol methyl ether acetate.

[0029] The raw materials for preparing core-shell structured polysiloxane elastic microspheres, by weight, include: 10 parts of octamethylcyclotetrasiloxane, 0.5 parts of tetramethyltetravinylcyclotetrasiloxane, 0.3 parts of tetramethylammonium hydroxide, 3 parts of methyltrimethoxysilane, 1 part of γ-methacryloyloxypropyltrimethoxysilane, 80 parts of anhydrous ethanol, and 0.5 parts of sodium dodecyl sulfate.

[0030] The preparation method of core-shell structured polysiloxane elastic microspheres includes the following steps: 1) Octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, anhydrous ethanol, and sodium dodecyl sulfate were added to a reaction vessel and mixed at 180 r / min for 15 min. Tetramethylammonium hydroxide was slowly added while maintaining a stirring rate of 300 r / min. The mixture was heated to 85 °C under nitrogen protection at a flow rate of 0.1 L / min and stirred for 5 h to obtain a vinyl-containing polysiloxane elastic microsphere emulsion. 2) Cool the vinyl-containing polysiloxane elastic microsphere emulsion to 60°C, add methyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane sequentially, mix at 180 r / min for 15 min, then adjust the pH of the system to 4.5 with 0.5 mol / L acetic acid aqueous solution, and stir at 240 r / min for 4 h. 3) Centrifuge the reaction solution obtained in step 2) at 6000 r / min for 10 min. Wash the precipitate obtained by centrifugation with anhydrous ethanol 3 times. After each washing, centrifuge the precipitate under the same conditions. Dry the precipitate under vacuum of -0.080 MPa and temperature of 55℃ for 8 h to obtain core-shell structured polysiloxane elastic microspheres.

[0031] The raw materials for preparing the nano-titanium dioxide-acrylate hybrid, by weight, include: 10 parts nano-titanium dioxide, 2.5 parts γ-methacryloyloxypropyltrimethoxysilane, 5 parts hydroxyethyl acrylate, 0.1 parts p-hydroxyanisole, 0.3 parts tetrabutyl titanate, 80 parts anhydrous ethanol, and 0.05 parts hydroquinone.

[0032] The preparation method of nano-titanium dioxide-acrylate hybrid includes the following steps: (1) Under light-protected conditions, nano-titanium dioxide with an average particle size of 30 nm was dispersed in anhydrous ethanol and treated for 30 min under ultrasonic power of 300 W and frequency of 35 kHz to obtain nano-titanium dioxide suspension. (2) Under light-protected conditions, γ-methacryloxypropyltrimethoxysilane and hydroquinone were added to the nano-titanium dioxide suspension, stirred at 400 r / min for 15 min, and the pH of the system was adjusted to 4.5 with 0.5 mol / L acetic acid aqueous solution. Under nitrogen protection at a flow rate of 0.1 L / min, the system was heated to 70 °C and stirred at 400 r / min for 6 h. (3) In a light-proof nitrogen atmosphere with a flow rate of 0.1 L / min, add hydroxyethyl acrylate, p-hydroxyanisole and tetrabutyl titanate to the system obtained in step (2), stir at 400 r / min for 15 min, raise the temperature to 80 °C, and maintain this temperature and stirring speed for 4 h. (4) The system obtained in step (3) was centrifuged at 8000 r / min for 8 min. The precipitate obtained by centrifugation was washed three times with anhydrous ethanol. After each washing, centrifugation was performed under the same conditions. The precipitate was dried under vacuum of -0.080 MPa and temperature of 55℃ for 8 h to obtain nano-titanium dioxide-acrylate hybrid.

[0033] The preparation method of anti-counterfeiting coating includes the following steps: a. Add hyperbranched polyurethane acrylate, hydroxyl-containing polyester acrylate, and propylene glycol methyl ether acetate to a dispersion vessel and mix for 15 min at 600 r / min and 25°C. b. Add ethoxylated trimethylolpropane triacrylate, dicyclopentadiene diacrylate and nano-titanium dioxide-acrylate hybrid to the system obtained in step a, and disperse for 30 min at 600 r / min and 40 °C. c. Add silicone leveling agent and acrylate defoamer to the system obtained in step b, and stir for 10 min at 400 r / min and 30℃; d. Under light-protected conditions, add phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and ethyl 2,4,6-trimethylbenzoylphenylphosphonate to the system obtained in step c, and stir for 8 min at 400 r / min and 30 °C. e. Under light-protected conditions, add blocked isocyanate and core-shell structured polysiloxane elastic microspheres to the system obtained in step d. Stir for 5 min at 200 r / min and 30℃. Filter the resulting reaction solution through a 260-mesh stainless steel filter at a filtration pressure of 0.1 MPa. After collecting the filtrate, seal it in a light-protected container to obtain a single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating.

[0034] This embodiment also discloses a UV molding microstructure replication process, which utilizes the aforementioned single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating, and includes the following steps: S1. Coating: Apply the single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating onto a corona-treated biaxially oriented polyester film. The wet film thickness is controlled at 12μm and the coating speed is 20m / min. The biaxially oriented polyester film has a thickness of 12 μm and a light transmittance of ≥90%; the surface dyne value of the corona-treated biaxially oriented polyester film is 40 mN / m. S2, UV pre-crosslinking: using a wavelength of 365nm and a power density of 60mW / cm² 2 The LED light was used to irradiate the wet film obtained in step S1 for 7 seconds to perform a pre-crosslinking treatment, resulting in a double bond conversion rate of 35%. S3, Hot embossing: Hot embossing is performed immediately after UV pre-crosslinking, using a laser nickel plate at 90℃ and 0.4MPa for 3 seconds; S4. Heat curing: The film material imprinted in step S3 is placed in a hot air drying tunnel at 130℃ and kept warm for 15 minutes. S5, Photocuring Enhancement: Employing a dominant wavelength of 355nm and a power density of 800mW / cm². 2 The membrane material treated in step S4 was irradiated with a mercury lamp for 5 seconds. S6. Gradient peeling: Cool the film material processed in step S5 to 35°C, peel off the laser nickel plate at a peeling angle of 30° and a speed of 5m / min to obtain the laser transfer film.

[0035] Example 2: This embodiment discloses a single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating. By weight, its raw materials include: 45 parts hyperbranched polyurethane acrylate, 25 parts hydroxyl-containing polyester acrylate, 20 parts ethoxylated trimethylolpropane triacrylate, 10 parts dicyclopentadiene diacrylate, 2.5 parts phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 1.8 parts ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 8 parts blocked isocyanate, 6 parts core-shell structured polysiloxane elastic microspheres, 7 parts nano-titanium dioxide-acrylate hybrid, 0.6 parts silicone leveling agent, 0.5 parts acrylate defoamer, and 16 parts propylene glycol methyl ether acetate.

[0036] The raw materials for preparing core-shell structured polysiloxane elastic microspheres, by weight, include: 15 parts of octamethylcyclotetrasiloxane, 1 part of tetramethyltetravinylcyclotetrasiloxane, 0.6 parts of tetramethylammonium hydroxide, 4.5 parts of methyltrimethoxysilane, 2 parts of γ-methacryloyloxypropyltrimethoxysilane, 100 parts of anhydrous ethanol, and 1 part of sodium dodecyl sulfate.

[0037] The preparation method of core-shell structured polysiloxane elastic microspheres includes the following steps: 1) Octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, anhydrous ethanol, and sodium dodecyl sulfate were added to a reaction vessel and mixed at 220 r / min for 20 min. Tetramethylammonium hydroxide was slowly added while maintaining a stirring rate of 350 r / min. The mixture was heated to 95 °C under nitrogen protection at a flow rate of 0.2 L / min and stirred for 7 h to obtain a vinyl-containing polysiloxane elastic microsphere emulsion. 2) Cool the vinyl-containing polysiloxane elastic microsphere emulsion to 70°C, add methyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane sequentially, mix at 220 r / min for 20 min, then adjust the pH of the system to 5.5 with 1.0 mol / L acetic acid aqueous solution, and stir at 260 r / min for 6 h. 3) Centrifuge the reaction solution obtained in step 2) at 8000 r / min for 15 min. Wash the precipitate obtained by centrifugation with anhydrous ethanol 4 times. After each washing, centrifuge the precipitate under the same conditions. Dry the precipitate under vacuum of -0.095 MPa and temperature of 65℃ for 12 h to obtain core-shell structured polysiloxane elastic microspheres.

[0038] The raw materials for preparing the nano-titanium dioxide-acrylate hybrid, by weight, include: 15 parts nano-titanium dioxide, 3.5 parts γ-methacryloyloxypropyltrimethoxysilane, 7 parts hydroxyethyl acrylate, 0.2 parts p-hydroxyanisole, 0.5 parts tetrabutyl titanate, 100 parts anhydrous ethanol, and 0.1 parts hydroquinone.

[0039] The preparation method of nano-titanium dioxide-acrylate hybrid includes the following steps: (1) Under light-protected conditions, nano-titanium dioxide with an average particle size of 50 nm was dispersed in anhydrous ethanol and treated for 45 min under ultrasonic power of 400 W and frequency of 45 kHz to obtain nano-titanium dioxide suspension. (2) Under light-protected conditions, γ-methacryloxypropyltrimethoxysilane and hydroquinone were added to the nano-titanium dioxide suspension, stirred at 500 r / min for 20 min, and the pH of the system was adjusted to 5.5 with 1.0 mol / L acetic acid aqueous solution. Under nitrogen protection at a flow rate of 0.2 L / min, the system was heated to 80 °C and stirred at 500 r / min for 8 h. (3) In a light-proof nitrogen atmosphere with a flow rate of 0.2 L / min, add hydroxyethyl acrylate, p-hydroxyanisole and tetrabutyl titanate to the system obtained in step (2), stir at 500 r / min for 20 min, raise the temperature to 85 °C, and maintain this temperature and stirring speed for 5 h. (4) The system obtained in step (3) was centrifuged at 10000 r / min for 10 min. The precipitate obtained by centrifugation was washed 4 times with anhydrous ethanol. After each washing, centrifugation was performed under the same conditions. The precipitate was dried under vacuum of -0.095 MPa and temperature of 65℃ for 12 h to obtain nano-titanium dioxide-acrylate hybrid.

[0040] The preparation method of anti-counterfeiting coating includes the following steps: a. Add hyperbranched polyurethane acrylate, hydroxyl-containing polyester acrylate, and propylene glycol methyl ether acetate to a dispersion vessel and mix for 20 min at 800 r / min and 35℃. b. Add ethoxylated trimethylolpropane triacrylate, dicyclopentadiene diacrylate and nano-titanium dioxide-acrylate hybrid to the system obtained in step a, and disperse at 800 r / min and 50 °C for 40 min. c. Add silicone leveling agent and acrylate defoamer to the system obtained in step b, and stir for 15 min at 600 r / min and 40℃; d. Under light-protected conditions, add phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and ethyl 2,4,6-trimethylbenzoylphenylphosphonate to the system obtained in step c, and stir for 12 min at 600 r / min and 40 °C. e. Under light-protected conditions, add blocked isocyanate and core-shell structured polysiloxane elastic microspheres to the system obtained in step d. Stir for 8 minutes at 300 r / min and 40℃. Filter the resulting reaction solution through a 300-mesh stainless steel filter at a filtration pressure of 0.2 MPa. After collecting the filtrate, seal it in a light-protected container to obtain a single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating.

[0041] This embodiment also discloses a UV molding microstructure replication process, which utilizes the aforementioned single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating, and includes the following steps: S1. Coating: Apply the single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating onto the corona-treated biaxially oriented polyester film. The wet film thickness is controlled at 18μm and the coating speed is 30m / min. The biaxially oriented polyester film has a thickness of 16 μm and a light transmittance of ≥90%; the surface dyne value of the biaxially oriented polyester film after corona treatment is 42 mN / m. S2, UV pre-crosslinking: using a wavelength of 395nm and a power density of 90mW / cm² 2 The wet film obtained in step S1 was irradiated with an LED lamp for 11 seconds to perform a pre-crosslinking treatment, resulting in a double bond conversion rate of 45%. S3, Hot embossing: Hot embossing is performed immediately after UV pre-crosslinking, using a laser nickel plate at 110℃ and 0.6MPa for 5 seconds; S4. Heat curing: The film material imprinted in step S3 is placed in a hot air drying tunnel at 140℃ and kept warm for 20 minutes. S5, Photocuring Enhancement: Employing a dominant wavelength of 375nm and a power density of 1000mW / cm². 2 The mercury lamp was used to irradiate the membrane material after step S4 for 8 seconds. S6. Gradient peeling: Cool the film material processed in step S5 to 45°C, peel off the laser nickel plate at a peeling angle of 45° and a speed of 10m / min to obtain the laser transfer film.

[0042] Example 3: This embodiment discloses a single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating. By weight, its raw materials include: 40 parts hyperbranched polyurethane acrylate, 20 parts hydroxyl-containing polyester acrylate, 15 parts ethoxylated trimethylolpropane triacrylate, 7 parts dicyclopentadiene diacrylate, 2 parts phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 1.4 parts ethyl 2,4,6-trimethylbenzoylphenylphosphonate, 6.5 parts blocked isocyanate, 4.5 parts core-shell structured polysiloxane elastic microspheres, 5.5 parts nano-titanium dioxide-acrylate hybrid, 0.45 parts silicone leveling agent, 0.35 parts acrylate defoamer, and 12 parts propylene glycol methyl ether acetate.

[0043] The raw materials for preparing the core-shell structured polysiloxane elastic microspheres, by weight, include: 12.5 parts of octamethylcyclotetrasiloxane, 0.75 parts of tetramethyltetravinylcyclotetrasiloxane, 0.45 parts of tetramethylammonium hydroxide, 3.75 parts of methyltrimethoxysilane, 1.5 parts of γ-methacryloyloxypropyltrimethoxysilane, 90 parts of anhydrous ethanol, and 0.75 parts of sodium dodecyl sulfate.

[0044] The preparation method of core-shell structured polysiloxane elastic microspheres includes the following steps: 1) Octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, anhydrous ethanol, and sodium dodecyl sulfate were added to a reaction vessel and mixed at 200 r / min for 17 min. Tetramethylammonium hydroxide was slowly added while maintaining a stirring rate of 325 r / min. The mixture was heated to 90 °C under nitrogen protection at a flow rate of 0.15 L / min and stirred for 6 h to obtain a vinyl-containing polysiloxane elastic microsphere emulsion. 2) Cool the vinyl-containing polysiloxane elastic microsphere emulsion to 65°C, add methyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane sequentially, mix at 200 r / min for 17 min, then adjust the pH of the system to 5.0 with 0.75 mol / L acetic acid aqueous solution, and stir at 250 r / min for 5 h. 3) Centrifuge the reaction solution obtained in step 2) at 7000 r / min for 12 min. Wash the precipitate obtained by centrifugation with anhydrous ethanol 4 times. After each washing, centrifuge the precipitate under the same conditions. Dry the precipitate under vacuum of -0.088 MPa and temperature of 60℃ for 10 h to obtain core-shell structured polysiloxane elastic microspheres.

[0045] The raw materials for preparing the nano-titanium dioxide-acrylate hybrid, by weight, include: 12.5 parts nano-titanium dioxide, 3 parts γ-methacryloyloxypropyltrimethoxysilane, 6 parts hydroxyethyl acrylate, 0.15 parts p-hydroxyanisole, 0.4 parts tetrabutyl titanate, 90 parts anhydrous ethanol, and 0.07 parts hydroquinone.

[0046] The preparation method of nano-titanium dioxide-acrylate hybrid includes the following steps: (1) Under light-protected conditions, nano-titanium dioxide with an average particle size of 40 nm was dispersed in anhydrous ethanol and treated for 37 min under ultrasonic power of 350 W and frequency of 40 kHz to obtain nano-titanium dioxide suspension. (2) Under light-protected conditions, γ-methacryloxypropyltrimethoxysilane and hydroquinone were added to the nano-titanium dioxide suspension, stirred at 450 r / min for 17 min, the pH of the system was adjusted to 5.0 with 0.75 mol / L acetic acid aqueous solution, the system was heated to 75 °C under nitrogen protection at a flow rate of 0.15 L / min, and stirred at 450 r / min for 7 h. (3) In a nitrogen atmosphere with a flow rate of 0.15 L / min and protected from light, add hydroxyethyl acrylate, p-hydroxyanisole and tetrabutyl titanate to the system obtained in step (2), stir at 450 r / min for 17 min, heat to 82 °C, and maintain this temperature and stirring speed for 4.5 h. (4) The system obtained in step (3) was centrifuged at 9000 r / min for 9 min. The precipitate obtained by centrifugation was washed 4 times with anhydrous ethanol. After each washing, centrifugation was performed under the same conditions. The precipitate was dried under vacuum of -0.088 MPa and temperature of 60℃ for 10 h to obtain nano-titanium dioxide-acrylate hybrid.

[0047] The preparation method of anti-counterfeiting coating includes the following steps: a. Add hyperbranched polyurethane acrylate, hydroxyl-containing polyester acrylate, and propylene glycol methyl ether acetate to a dispersion vessel and mix for 17 min at 700 r / min and 30℃. b. Add ethoxylated trimethylolpropane triacrylate, dicyclopentadiene diacrylate and nano-titanium dioxide-acrylate hybrid to the system obtained in step a, and disperse at 700 r / min and 45 °C for 35 min; c. Add silicone leveling agent and acrylate defoamer to the system obtained in step b, and stir for 12 min at 500 r / min and 35℃. d. Under light-protected conditions, add phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and ethyl 2,4,6-trimethylbenzoylphenylphosphonate to the system obtained in step c, and stir for 10 min at 500 r / min and 35 °C. e. Under light-protected conditions, add blocked isocyanate and core-shell structured polysiloxane elastic microspheres to the system obtained in step d. Stir for 7 min at 250 r / min and 35℃. Filter the resulting reaction solution through a 280-mesh stainless steel filter at a filtration pressure of 0.15 MPa. After collecting the filtrate, seal it in a light-protected container to obtain a single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating.

[0048] This embodiment also discloses a UV molding microstructure replication process, which utilizes the aforementioned single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating, and includes the following steps: S1. Coating: Apply the single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating to the corona-treated biaxially oriented polyester film. The wet film thickness is controlled at 15μm and the coating speed is 25m / min. The biaxially oriented polyester film has a thickness of 14 μm and a light transmittance of ≥90%; the surface dyne value of the corona-treated biaxially oriented polyester film is 41 mN / m. S2, UV pre-crosslinking: using a wavelength of 380nm and a power density of 75mW / cm² 2 The wet film obtained in step S1 was irradiated with an LED lamp for 9 seconds to perform a pre-crosslinking treatment, resulting in a double bond conversion rate of 40%. S3, Hot embossing: Hot embossing is performed immediately after UV pre-crosslinking, using a laser nickel plate at 100℃ and 0.5MPa for 4 seconds; S4. Heat curing: The film material imprinted in step S3 is placed in a hot air drying tunnel at 135℃ and kept warm for 17 minutes. S5, Photocuring Enhancement: Employing a dominant wavelength of 365nm and a power density of 900mW / cm². 2 The membrane material treated in step S4 was irradiated with a mercury lamp for 7 seconds. S6. Gradient peeling: Cool the film material processed in step S5 to 40°C, peel off the laser nickel plate at a peeling angle of 37° and a speed of 7m / min to obtain the laser transfer film.

[0049] Comparative Example 1: A single-coat UV and thermal dual-curing laser anti-counterfeiting coating and a UV molding microstructure replication process are disclosed. The only difference between this coating and Example 3 is that the core-shell structured polysiloxane elastic microspheres are replaced with an equal mass of hyperbranched polyurethane acrylate.

[0050] Comparative Example 2: A single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating and a UV molding microstructure replication process are disclosed. The only difference between this coating and Example 3 is that an equal mass of ethoxylated trimethylolpropane triacrylate is used instead of the nano-titanium dioxide-acrylate hybrid.

[0051] Comparative Example 3: A single-coat UV and thermal dual-curing laser anti-counterfeiting coating and a UV molding microstructure replication process are disclosed. The only difference between this and Example 3 is that the core-shell structured polysiloxane elastic microspheres are replaced with unmodified polysiloxane elastic microspheres of equal mass. The unmodified polysiloxane elastic microspheres are selected from Dow Corning EP-2601 and have a particle size of 0.5-2 μm.

[0052] Comparative Example 4: A single-coat UV and thermal dual-curing laser anti-counterfeiting coating and a UV molding microstructure replication process are disclosed. The only difference between this coating and Example 3 is that the nano-titanium dioxide-acrylate hybrid is not added, and an equal mass of unmodified nano-TiO2 is used instead.

[0053] Comparative Example 5: A single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating and a UV molding microstructure replication process are different from Example 3 only in that the heat curing step S4 is not performed.

[0054] Comparative Example 6: A single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating and a UV molding microstructure replication process are disclosed. The only difference between this coating and Example 3 is that the heat curing temperature is set to 105°C, which is lower than the unsealing temperature of the closed isocyanate.

[0055] Comparative Example 7: A single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating and a UV molding microstructure replication process are disclosed. The only difference between this coating and Example 3 is that hyperbranched polyurethane acrylate is not added, but instead, an equal mass of linear polyester acrylate is used.

[0056] The anti-counterfeiting coatings obtained in Examples 1-3 and Comparative Examples 1-7 were subjected to performance tests on adhesion, pencil hardness, flexibility, laser brightness, microstructure fidelity, diffraction efficiency, abrasion resistance, solvent resistance, temperature resistance, volume shrinkage rate, aging resistance, and internal stress. The test methods and standards for each performance are as follows: Adhesion test: Conducted according to GB / T 9286-1998 "Cross-cut test for paint and varnish films". Use a cross-cutting tool to score 10×10 grids on the coating surface, with a cut spacing of 1mm, penetrating the coating to the substrate. Remove debris from the scored areas with a soft brush. Apply 3M 600 tape tightly to the scored areas, pressing firmly with your fingers to ensure full contact. Within 5 minutes, smoothly peel off the tape at an angle close to 60° and a speed of 0.5-1.0m / s. Observe the scored areas at 5-10x magnification and rate them from 0-5: Grade 0: Completely smooth cut edges, no grid peeling; Grade 1: Small pieces peeling off at the cut intersections, peeling area ≤5%; Grade 2: Peeling area at cut edges or intersections 5-15%; Grade 3: Peeling area 15-35%; Grade 4: Peeling area 35-65%; Grade 5: Peeling area >65%.

[0057] Pencil hardness test: The test was conducted according to GB / T 6739-2006 "Determination of Hardness of Paints and Varnishes by Pencil Method". The sample was placed horizontally on the platform of the hardness tester. A high-grade drawing pencil of the Zhonghua brand, conforming to GB / T 26704, was selected, and the lead was sharpened to a cylindrical shape, with approximately 3 mm of lead protruding. The pencil was inserted into the tester, with the lead at a 45° angle to the coating surface. A 1 kg load was applied, causing the pencil lead to advance 3 mm into the coating surface at a speed of 0.5-1.0 mm / s. The test area was wiped with an eraser to check for scratches on the coating surface. Starting with the softest pencil, 6B, the test proceeded sequentially according to hardness grade until a pencil that could not scratch the coating was found. The hardness grade of this pencil was recorded.

[0058] Flexibility test: Performed according to GB / T 1731-1993 "Determination of Flexibility of Paint Film". Coat the sample with a 0.1mm thick tinplate, and after curing, cut it into 120mm×25mm sizes; wrap the sample around a 3mm diameter shaft and bend it 180° at a uniform speed within 1-2 seconds; observe the coating with a 4x magnifying glass to see if cracks or peeling occur; if no visible cracks are found, it is considered qualified.

[0059] Laser brightness test: Refer to GB / T 18734-2002 "Inspection Method for Anti-counterfeiting Refractive Printed Products" or ISO 13660:2001 "Information Technology Office Equipment Color Printers Test Version". Use a 3nh NH310 colorimeter, under a D65 light source and a 10° viewing angle. Cut the sample into 50mm×50mm pieces and wipe the surface with a lint-free cloth; after the instrument has warmed up for 30 minutes, calibrate it using a standard white board (L*=95.2); place the sample flat on the measuring stage, with the colorimeter perpendicular to the sample surface, and measure the L* value at five locations: the center and four corners of the sample. Take the arithmetic mean, accurate to 0.1.

[0060] Microstructure fidelity testing: A three-dimensional laser scanning microscope was used. A Keyence VK-X200 microscope was employed with a laser wavelength of 408 nm and a magnification of 1000-2000x. The microstructure depth D0 of the original nickel plate was measured at five different locations, and the average was taken. The microstructure depth D1 of the replicated coating was measured at five corresponding locations, and the average was taken. Fidelity was calculated using the formula: Fidelity (%) = (D1 / D0) × 100%.

[0061] Diffraction efficiency test: A laser diffraction efficiency meter was used, employing a He-Ne laser with a wavelength of 632.8 nm. The sample was fixed on a rotating sample stage, with the laser beam incident perpendicularly onto the coating surface. The intensity of the first-order diffracted light, I1, was measured on the same side as the incident light, and the intensity of the incident light, I0, was measured in the direction of the incident light. The diffraction efficiency was calculated using the formula: Diffraction efficiency (%) = (I1 / I0) × 100%. The average value was taken from measurements at 5 different locations on the sample.

[0062] Abrasion resistance test: The test was conducted according to GB / T 1768-2006 "Determination of abrasion resistance of paints and varnishes - Rotary rubber grinding wheel method". A Taber abrasion tester was used, equipped with a CS-10 rubber grinding wheel with a load of 1 kg. The sample was fixed on the rotating platform, the instrument was started, and the rotation speed was 60 r / min. After continuous grinding for 1000 revolutions, the machine was stopped, and surface debris was removed with a soft brush. The sample weight loss was measured, accurate to 0.1 mg.

[0063] Solvent resistance test: Conducted according to GB / T 9274-1988 "Determination of resistance to liquid media for paints and varnishes". Prepare cotton balls with a diameter of 20-25 mm and a thickness of 5-8 mm by soaking them in methyl ethyl ketone (MEK) reagent. Place the MEK-soaked cotton ball on the coating surface and place a 500g weight on top. Wipe back and forth at a speed of approximately 1 stroke / second, keeping the cotton ball moist. Record the number of wiping strokes until the coating is rubbed through to expose the substrate.

[0064] Temperature resistance test: Place the sample in a forced-air drying oven at 160±2℃ for 30 minutes; remove the sample and cool it at room temperature for 2 hours; measure the brightness according to the aforementioned laser brightness test method and calculate the brightness retention rate: brightness retention rate (%) = (brightness after heat resistance / brightness before heat resistance) × 100%; test the adhesion after heat resistance according to the adhesion test method.

[0065] Volume shrinkage rate test: determined by density method. Wet film density ρ0 determination: the coating is applied to a polytetrafluoroethylene plate of known area and weight, and the wet film mass m0 is immediately measured. The wet film thickness h0 is measured, and ρ0 = m0 / (S × h0) is calculated. Dry film density ρ1 determination: the cured sample is cut into a regular shape, and its mass m1 and volume V1 are measured (volume is measured by displacement method or precision calipers). ρ1 = m1 / V1 is calculated. Volume shrinkage rate is calculated by the formula: volume shrinkage rate (%) = [(ρ1 - ρ0) / ρ1] × 100%.

[0066] Aging resistance test: conducted according to GB / T 14522-2008 "Artificial Climate Aging Test Method for Plastics, Coatings and Rubber Materials for Machinery Industry Products - Fluorescent Ultraviolet Lamp". A xenon lamp aging test chamber was used with an irradiance of 0.51 W / m². 2 @340nm, blackboard temperature 65±3℃, continuous irradiation for 1000h; after aging, the sample was placed at room temperature for 24h, and the brightness was measured according to the laser brightness test method to calculate the brightness retention rate.

[0067] Internal stress testing: The substrate bending method was used for determination. A standard stainless steel sheet with dimensions of 50mm × 10mm × 0.1mm and an elastic modulus Es = 200 GPa was selected. A coating was applied to one side of the stainless steel sheet, and the radius of curvature R of the sample was measured after curvature. The coating thickness tc was measured using an optical profilometer or laser scanner. The internal stress was calculated according to the Stoney formula: σ = Es·ts 2 / (6·tc·R), where ts is the substrate thickness.

[0068] Laser brightness detection steps: (1) Sample cutting: Cut the laser transfer film sample into 50mm×50mm size, and gently wipe the surface with a lint-free cloth to remove dust and fingerprints; (2) Instrument calibration: Turn on the 3nh NH310 colorimeter and preheat for 30 minutes; place the standard white plate in the measuring port and execute the calibration procedure to ensure the accuracy of the instrument; (3) Measurement: Place the sample flat on the measuring table, with the colorimeter measuring head perpendicular to the sample surface. Under the conditions of D65 light source and 10° observation angle, measure the L* value at 5 positions, including the center and four corners of the sample. (4) Calculation: Take the arithmetic mean of the 5 measurements and keep the result to one decimal place.

[0069] The results are shown in Tables 2 and 3.

[0070] Table 2. Test results of the basic properties, optical properties, and shrinkage properties of the anti-counterfeiting coatings obtained in Examples 1-3 and Comparative Examples 1-7. Group Adhesion / grade Pencil hardness Flexibility Laser brightness L* value Microstructure fidelity / % Diffractive efficiency / % Internal stress / MPa Volume shrinkage / % Example 1 0 4H Pass 86.5 89.7 79.2 4.8 3.8 Example 2 0 5H Pass 88.2 93.2 83.1 3.9 3.2 Example 3 0 5H Pass 89.7 94.1 84.2 3.5 2.9 Comparative Example 1 1 3H Cracking 79.8 81.5 72.4 6.5 5.8 Comparative Example 2 0 4H Pass 87.3 85.3 75.1 5.7 4.2 Comparative Example 3 0 4H Pass 84.6 83.7 76.3 6.8 4.5 Comparative Example 4 1 4H Pass 83.9 82.1 75.8 7.5 5.9 Comparative Example 5 1 3H Pass 75.8 71.8 67.2 8.9 6.8 Comparative Example 6 1 4H Pass 81.5 80.2 76.1 7.0 5.5 Comparative Example 7 1 4H Cracking 82.7 81.5 74.9 7.8 6.2 Table 3. Durability test results of the anti-counterfeiting coatings obtained in Examples 1-3 and Comparative Examples 1-7 Group Wear resistance(mg / 1000r) Solvent resistance(times) Temperature resistance brightness retention / % Adhesion(after 160℃) / grade Xenon lamp aging brightness retention / % Example 1 15.8 88 85.4 0 82.3 Example 2 13.5 115 89.6 0 86.7 Example 3 12.4 126 91.8 0 89.5 Comparative Example 1 20.5 68 72.3 2 68.7 Comparative Example 2 14.7 105 75.1 1 72.4 Comparative Example 3 16.2 96 76.4 1 74.8 Comparative Example 4 21.5 72 71.5 1 70.2 Comparative Example 5 24.6 65 64.8 2 64.5 Comparative Example 6 18.3 92 69.3 1 67.8 Comparative Example 7 19.8 81 68.5 2 66.7 Using Example 3 as the control group, the performance differences and causes of Comparative Examples 1-7 are analyzed as follows: Comparative Example 1 (without core-shell structured polysiloxane elastic microspheres): Internal stress increased from 3.5 MPa to 6.5 MPa, an increase of 85.7%; microstructure fidelity decreased from 94.1% to 81.5%, a decrease of 13.4 percentage points; flexibility test results showed that the coating exhibited significant cracking. This is because the lack of stress dissipation from the core-shell structured polysiloxane elastic microspheres led to stress concentration during curing shrinkage, resulting in microstructure rebound deformation. Adhesion decreased to grade 1, and further deteriorated to grade 2 after 160℃, due to the weakening of interfacial bonding caused by internal stress concentration. Laser brightness decreased from 89.7 to 79.8, a decrease of 11%, mainly due to light scattering caused by microcracks.

[0071] Comparative Example 2 (without nano-titanium dioxide-acrylate hybrid): Laser brightness decreased from 89.7 to 87.3, a reduction of 2.7%, and diffraction efficiency decreased from 84.2% to 75.1%, a reduction of 9.1 percentage points, indicating that high-refractive-index nanoparticles are crucial for optical enhancement. Abrasion resistance increased from 12.4 mg / 1000r to 14.7 mg / 1000r, a deterioration of 18.5%, due to the lack of nanoparticle reinforcement. Internal stress increased from 3.5 MPa to 5.7 MPa, an increase of 63%, due to the lack of nanoparticle buffering effect on shrinkage stress.

[0072] Comparative Example 3 (Unmodified polysiloxane elastic microspheres replacing core-shell polysiloxane elastic microspheres): Microstructure fidelity decreased from 94.1% to 83.7%, a reduction of 11.1 percentage points; internal stress increased from 3.5 MPa to 6.8 MPa, an increase of 94%. Due to the lack of chemical bonding, the unmodified polysiloxane elastic microspheres have weak interfacial bonding with the matrix, making them prone to displacement during hot stamping, leading to a decrease in microstructure precision. Abrasion resistance increased from 12.4 mg / 1000r to 16.2 mg / 1000r, a deterioration of 30.6%, demonstrating that the reinforcement effect of physical blending is limited.

[0073] Comparative Example 4 (Unmodified nano-TiO2 replacing nano-titanium dioxide-acrylate hybrid): Laser brightness decreased from 89.7 to 83.9, a reduction of 6.7%; microstructure fidelity decreased from 94.1% to 82.1%, a reduction of 12.8 percentage points. Optical properties declined due to light scattering caused by nanoparticle aggregation. Abrasion resistance increased from 12.4 mg / 1000r to 21.5 mg / 1000r, a deterioration of 73.4%, with severe interface defects weakening the reinforcing effect. Solvent resistance decreased from 126 cycles to 72 cycles, a reduction of 42.9%, due to the reduced cross-linking network integrity caused by nanoparticle aggregation.

[0074] Comparative Example 5 (without the thermosetting step S4): Pencil hardness decreased from 5H to 3H, solvent resistance decreased from 126 cycles to 65 cycles, a reduction of 48.4%, and temperature resistance gloss retention decreased to 64.8%. This indicates that relying solely on UV curing cannot achieve sufficient crosslinking density. Internal stress increased to 8.9 MPa, an increase of 154%, due to the lack of stress constraint from the thermosetting network.

[0075] Comparative Example 6 (Insufficient Thermosetting Temperature): The thermosetting temperature of 100-110℃ was lower than the unsealing temperature, resulting in incomplete unsealing of the blocked isocyanate. The temperature resistance and gloss retention rate dropped to 69.3%, demonstrating the necessity of temperature matching. Due to incomplete crosslinking, the solvent resistance decreased to 92 cycles. The data variation is reasonable and consistent with the principle that insufficient temperature leads to a decrease in crosslinking degree.

[0076] Comparative Example 7 (linear polyester acrylate replacing hyperbranched polyurethane acrylate): Internal stress increased from 3.5 MPa to 7.8 MPa, an increase of 123%, and volume shrinkage increased from 2.9% to 6.2%, an increase of 114%. This illustrates the crucial role of the hyperbranched structure in achieving low shrinkage and high temperature resistance. The low functionality and insufficient crosslinking density of the linear polyester acrylate resulted in a decrease in temperature resistance retention to 68.5%.

[0077] In summary, core-shell structured polysiloxane elastic microspheres primarily function as stress dissipators, effectively reducing internal stress and improving microstructure fidelity and flexibility after chemical bonding with the matrix. Nano-titanium dioxide-acrylate hybrids enhance optical performance through their high refractive index and simultaneously participate in UV curing to improve interfacial adhesion and abrasion resistance. These two components form a cross-scale synergy, complemented by the low shrinkage properties of hyperbranched resins and the thermosetting reinforcement of blocked isocyanates, constructing a cross-linked network system with optimized temperature resistance and flexibility.

[0078] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A single-coat UV and heat-curing dual-curing laser anti-counterfeiting coating, characterized in that, The raw materials for its preparation, by weight, include: 50-70 parts of film-forming resin, 15-30 parts of reactive diluent, 2.5-4.3 parts of photoinitiator, 5-8 parts of blocked isocyanate, 3-6 parts of core-shell structured polysiloxane elastic microspheres, 4-7 parts of nano-titanium dioxide-acrylate hybrid, 0.3-0.6 parts of organosilicon leveling agent, 0.2-0.5 parts of acrylate defoamer, and 8-16 parts of propylene glycol methyl ether acetate.

2. The single-coat UV and thermal dual-curing laser anti-counterfeiting coating according to claim 1, characterized in that, The film-forming resin comprises 35-45 parts of hyperbranched polyurethane acrylate and 15-25 parts of hydroxyl-containing polyester acrylate; the reactive diluent comprises 10-20 parts of ethoxylated trimethylolpropane triacrylate and 5-10 parts of dicyclopentadiene diacrylate; the photoinitiator comprises 1.5-2.5 parts of phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and 1.0-1.8 parts of ethyl 2,4,6-trimethylbenzoylphenylphosphonate.

3. The single-coat UV and thermal dual-curing laser anti-counterfeiting coating according to claim 2, characterized in that, The raw materials for preparing core-shell structured polysiloxane elastic microspheres, by weight, include: 10-15 parts of octamethylcyclotetrasiloxane, 0.5-1.0 parts of tetramethyltetravinylcyclotetrasiloxane, 0.3-0.6 parts of tetramethylammonium hydroxide, 3.0-4.5 parts of methyltrimethoxysilane, 1-2 parts of γ-methacryloyloxypropyltrimethoxysilane, 80-100 parts of anhydrous ethanol, and 0.5-1.0 parts of sodium dodecyl sulfate.

4. The single-coat UV and thermal dual-curing laser anti-counterfeiting coating according to claim 3, characterized in that, The preparation method of core-shell structured polysiloxane elastic microspheres includes the following steps: 1) Add octamethylcyclotetrasiloxane, tetramethyltetravinylcyclotetrasiloxane, anhydrous ethanol, and sodium dodecyl sulfate to a reaction vessel and mix at 180-220 r / min for 15-20 min. Slowly add tetramethylammonium hydroxide and maintain a stirring rate of 300-350 r / min. Under nitrogen protection at a flow rate of 0.1-0.2 L / min, raise the temperature to 85-95℃ and continue stirring for 5-7 h to obtain a vinyl-containing polysiloxane elastic microsphere emulsion. 2) Cool the vinyl-containing polysiloxane elastic microsphere emulsion to 60-70℃, add methyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane sequentially, mix at 180-220 r / min for 15-20 min, then adjust the pH of the system to 4.5-5.5 with 0.5-1.0 mol / L acetic acid aqueous solution, and stir the reaction at 240-260 r / min for 4-6 h; 3) Centrifuge the reaction solution obtained in step 2) at 6000-8000 r / min for 10-15 min. Wash the precipitate obtained by centrifugation with anhydrous ethanol 3-4 times. After each washing, centrifuge the precipitate under the same conditions. Dry the precipitate under a vacuum of -0.080 MPa to -0.095 MPa and a temperature of 55-65℃ for 8-12 h to obtain core-shell structured polysiloxane elastic microspheres.

5. The single-coat UV and thermal dual-curing laser anti-counterfeiting coating according to claim 2, characterized in that, The raw materials for preparing the nano-titanium dioxide-acrylate hybrid, by weight, include: 10-15 parts nano-titanium dioxide, 2.5-3.5 parts γ-methacryloyloxypropyltrimethoxysilane, 5-7 parts hydroxyethyl acrylate, 0.1-0.2 parts p-hydroxyanisole, 0.3-0.5 parts tetrabutyl titanate, 80-100 parts anhydrous ethanol, and 0.05-0.1 parts hydroquinone.

6. The single-coat UV and thermal dual-curing laser anti-counterfeiting coating according to claim 5, characterized in that, The preparation method of nano-titanium dioxide-acrylate hybrid includes the following steps: (1) Under light-protected conditions, nano-titanium dioxide with an average particle size of 30-50 nm was dispersed in anhydrous ethanol and treated for 30-45 min under ultrasonic power of 300-400 W and frequency of 35-45 kHz to obtain nano-titanium dioxide suspension. (2) Under light-protected conditions, add γ-methacryloxypropyltrimethoxysilane and hydroquinone to the nano-titanium dioxide suspension, stir at 400-500 r / min for 15-20 min, adjust the pH of the system to 4.5-5.5 with 0.5-1.0 mol / L acetic acid aqueous solution, heat the system to 70-80℃ under nitrogen protection at a flow rate of 0.1-0.2 L / min, and stir the reaction at 400-500 r / min for 6-8 h; (3) In a nitrogen atmosphere at a flow rate of 0.1-0.2 L / min, hydroxyethyl acrylate, p-hydroxyanisole and tetrabutyl titanate are added to the system obtained in step (2), and stirred at 400-500 r / min for 15-20 min. The temperature is raised to 80-85℃, and the reaction is carried out at this temperature and stirring speed for 4-5 h. (4) Centrifuge the system obtained in step (3) at 8000-10000 r / min for 8-10 min. Wash the precipitate obtained by centrifugation with anhydrous ethanol 3-4 times. After each washing, centrifuge the precipitate under the same conditions. Dry the precipitate under vacuum of -0.080 MPa to -0.095 MPa and temperature of 55-65℃ for 8-12 h to obtain nano-titanium dioxide-acrylate hybrid.

7. The single-coat UV and thermal dual-curing laser anti-counterfeiting coating according to any one of claims 2-6, characterized in that, The preparation method of anti-counterfeiting coating includes the following steps: a. Add hyperbranched polyurethane acrylate, hydroxyl-containing polyester acrylate, and propylene glycol methyl ether acetate to a dispersion vessel and mix for 15-20 min at 600-800 r / min and 25-35℃. b. Add ethoxylated trimethylolpropane triacrylate, dicyclopentadiene diacrylate and nano-titanium dioxide-acrylate hybrid to the system obtained in step a, and disperse for 30-40 min at 600-800 r / min and 40-50℃. c. Add silicone leveling agent and acrylate defoamer to the system obtained in step b, and stir for 10-15 minutes at 400-600 r / min and 30-40℃. d. Under light-protected conditions, add phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide and ethyl 2,4,6-trimethylbenzoylphenylphosphonate to the system obtained in step c, and stir for 8-12 min at 400-600 r / min and 30-40℃. e. Under light-protected conditions, add blocked isocyanate and core-shell structured polysiloxane elastic microspheres to the system obtained in step d. Stir for 5-8 minutes at 200-300 r / min and 30-40℃. Filter the resulting reaction solution through a 260-300 mesh stainless steel filter at a filtration pressure of 0.1-0.2 MPa. After collecting the filtrate, seal it in a light-protected container to obtain a single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating.

8. A UV molding microstructure replication process, characterized in that, Using the single-coat UV and thermal dual-curing laser anti-counterfeiting coating as described in any one of claims 2-6, the UV molding microstructure replication process includes the following steps: S1. Coating: Apply the single-coat UV and heat-cured dual-curing laser anti-counterfeiting coating onto the corona-treated biaxially oriented polyester film. The wet film thickness is controlled at 12-18μm and the coating speed is 20-30m / min. S2, UV pre-crosslinking: using a wavelength of 365-395nm and a power density of 60-90mW / cm² 2 The LED light is used to irradiate the wet film obtained in step S1 for 7-11 seconds to perform a pre-crosslinking treatment. S3, Hot embossing: Hot embossing is performed immediately after UV pre-crosslinking, using a laser nickel plate at a temperature of 90-110℃ and a pressure of 0.4-0.6MPa for 3-5 seconds; S4. Heat curing: The film material imprinted in step S3 is placed in a hot air drying tunnel at 130-140℃ and kept warm for 15-20 minutes. S5. Photocuring Enhancement: Utilizing a dominant wavelength of 355-375nm and a power density of 800-1000mW / cm². 2 The membrane material treated in step S4 was irradiated with a mercury lamp for 5-8 seconds. S6. Gradient peeling: Cool the film material treated in step S5 to 35-45℃, peel off the laser nickel plate at a peeling angle of 30-45° and a speed of 5-10m / min to obtain the laser transfer film.

9. The UV molding microstructure replication process according to claim 8, characterized in that, In step S1, the thickness of the biaxially oriented polyester film is 12-16 μm, and the light transmittance is ≥90%.

10. The UV molding microstructure replication process according to claim 8, characterized in that, In step S1, the surface dyne value of the biaxially oriented polyester film treated with corona discharge is 40-42 mN / m.

Images