A laser coating for laser films, its preparation method and application

Abstract

This application provides a laser coating for laser films, its preparation method, and its application. The laser coating comprises the following raw materials in parts by weight: 115 parts of composite acrylate, 5-10 parts of modified core-shell filler, 3-9 parts of photoinitiator, and 0.1-1 parts of leveling agent. The composite acrylate includes peptide-modified acrylate, hydroxyethyl acrylate, and polydipentaerythritol hexaacrylate, with a mass ratio of 1:(0.7-1):(0.8-1.2). The modified core-shell filler comprises a cerium dioxide core and a silica shell. This laser coating, when applied to laser films, imparts excellent weather resistance, making it suitable for packaging, decoration, security, and anti-counterfeiting applications, demonstrating good practical value and market prospects.

Description

Technical Field

[0001] This application relates to the field of laser coatings, and specifically discloses a laser coating for laser films, its preparation method, and its application. Background Technology

[0002] Laser coatings, with their ability to form a laser coating on the surface of a base film with a brilliant metallic texture and unique optical diffraction effects, are widely used in high-end packaging, decorative materials, and security and anti-counterfeiting fields. Laser film products are typically prepared through processes such as coating, embossing, and curing. In existing technologies, laser coatings used for laser films mostly use ordinary acrylic resins, polyurethane resins, etc., as the coating base material, combined with conventional fillers, photoinitiators, and other components to form a coating system. After UV curing, a laser coating is formed on the surface of the base film.

[0003] Traditional laser coatings generally suffer from insufficient weather resistance when exposed to outdoor environments for extended periods, primarily manifesting as yellowing and decreased gloss, which limits their lifespan and application range. Researchers have attempted to improve the weather resistance of laser coatings by optimizing the coating material itself. For example, patent CN109354976A describes a method that enhances the UV resistance of PET laser films by introducing a compound system of hindered amine and benzotriazole light stabilizers into a UV-cured laser coating system. The resulting material exhibits excellent performance in yellowing resistance tests.

[0004] However, the problem with the above-mentioned patent is that the added small molecule light stabilizers are prone to migration in long-term use or complex environments, which leads to a gradual decline in weather resistance and may not be able to achieve long-term protection. In addition, traditional UV-cured resin systems are still prone to brittleness and powdering, and the clarity and light transmittance of the laser coating are difficult to maintain stability in long-term use.

[0005] Therefore, there is an urgent need to develop a laser coating for laser films to meet the market demand for long-term and stable use of laser films. Summary of the Invention

[0006] This application provides a laser coating for laser films, its preparation method, and its application.

[0007] In a first aspect, this application provides a laser coating comprising the following raw materials in parts by weight: 115 parts of composite acrylate, 5-10 parts of modified core-shell filler, 3-9 parts of photoinitiator, and 0.1-1 parts of leveling agent; wherein the composite acrylate comprises peptide-modified acrylate, hydroxyethyl acrylate, and polydipentaerythritol hexaacrylate, and the mass ratio of peptide-modified acrylate, hydroxyethyl acrylate, and polydipentaerythritol hexaacrylate is 1:(0.7-1):(0.8-1.2); wherein the modified core-shell filler comprises a cerium dioxide core and a silica shell.

[0008] According to this application, the laser coating obtained by the above-mentioned formulation design can be applied to the laser film as a laser coating layer. While maintaining the high optical performance and excellent processability of the laser film, it can improve its resistance to ultraviolet aging and yellowing, and achieve long-term weather resistance of the laser film.

[0009] Specifically, in the modified core-shell filler, the CeO2 core is coated with a SiO2 shell. The CeO2 core can absorb ultraviolet light and may pass through Ce... 3+ / Ce 4+ Valence cycling eliminates UV-induced free radicals and inhibits the photo-oxidation chain reaction of laser coatings; the SiO2 shell can inhibit CeO2 nucleus aggregation, and the SiO2 shell can improve the dispersion and light transmission of CeO2 nuclei while maintaining the activity of CeO2.

[0010] Furthermore, in the molecular structure of peptide-modified acrylates, the amino and carboxyl groups abundant in the peptide chain can form a local polar network through intermolecular hydrogen bonds. Under temperature changes or external stress, the reversible breaking and reconstruction of hydrogen bonds helps to absorb and disperse some of the stress, reducing micro-cracks in the laser coating caused by thermal expansion and contraction. On the other hand, the flexible characteristics of the peptide chain can play a certain role in buffering external stress. Moreover, peptide-modified acrylates, hydroxyethyl acrylate (HEA), and polydipentaerythritol hexaacrylate (DPHA) undergo free radical copolymerization under the action of a photoinitiator, which helps to construct a complex cross-linked network structure. Among them, DPHA can act as a "cross-linking node" to provide dense covalent bond connections. Peptide-modified acrylates and HEA... The molecular chains of the DPHA can form a "bridging" effect between different nodes, which can increase the crosslinking density of the system and improve the integrity of the network to a certain extent. In addition, the rigid skeleton provided by DPHA helps to maintain the long-term stability of the coating, while HEA can act as a flexible spacer to alleviate local stress concentration. The peptide-modified acrylate provides a certain buffer transition between the rigid skeleton and the flexible spacer through the peptide chain. This rigid-flexible gradient difference can enable the laser coating to maintain high performance when environmental conditions change. At the same time, the hydroxyl groups of HEA can form a three-dimensional adsorption network with the carboxyl groups of the peptide chain. Through hydrogen bonding or polar interactions, it can interact with the polar small molecules that may be generated during aging, slowing down their hydrolysis or degradation of the polymer backbone and further improving weather resistance. When the mass ratio of peptide-modified acrylate, hydroxyethyl acrylate, and polydipentaerythritol hexaacrylate is controlled at 1:(0.7~1):(0.8~1.2), it is beneficial for the three to achieve a more matched reaction rate and degree of crosslinking during the photocuring process, thereby constructing a network structure with both high crosslinking density and dynamic reversibility. This structure helps to provide good physical barrier properties through a dense covalent crosslinked skeleton, and may also achieve stress dissipation and microcrack resistance through hydrogen bond network, which helps to improve the weather resistance of laser coatings.

[0011] Furthermore, the composite acrylate system can improve the dispersibility of the modified core-shell filler by interacting with the SiO2 shell through multi-component polar groups. The cross-linked network formed after photocuring can anchor the filler to the matrix, enhancing the interfacial bonding between the filler and the matrix. At the same time, the filler can provide physical support points for the cross-linked network, inhibiting the thermal motion of polymer molecular chains and reducing interfacial peeling or microcrack formation during aging. In addition, the SiO2 shell of the modified core-shell filler has a certain rigidity and chemical stability, which can improve the hardness and structural stability without reducing the flexibility of the coating, reducing the deformation and damage of the coating during aging, and ensuring the long-term effectiveness of the physical barrier and chemical protection functions.

[0012] In summary, through the synergistic effect of multiple components in laser coatings, the laser coating can achieve improved weather resistance while maintaining optical performance.

[0013] In some embodiments, the polypeptide-modified acrylate is obtained by a ring-opening grafting reaction between the polypeptide and an epoxy acrylate, wherein the epoxy acrylate includes glycidyl methacrylate.

[0014] In some of the above embodiments, peptide-modified acrylates are prepared by a ring-opening grafting reaction between peptides and epoxy acrylates. This reaction involves the formation of covalent bonds between the amino and epoxy groups in the peptide molecule, anchoring the peptide chain to the resin backbone and ensuring subsequent copolymerization with hydroxyethyl acrylate and polydipentaerythritol hexaacrylate. The introduced abundant amide bonds can form a dynamically reversible hydrogen bond network within the coating, promoting stress dissipation and inhibiting microcrack initiation, thereby endowing the laser coating with resistance to performance degradation and helping to achieve long-term weather resistance that cannot be achieved by ordinary blend systems. Glycidyl methacrylate contains highly reactive epoxy groups, which readily undergo nucleophilic ring-opening reactions with the peptide amino groups, laying the foundation for the construction of the crosslinking network of the laser coating.

[0015] In some embodiments, the polypeptide-modified acrylate is prepared by the following method:

[0016] Ten parts of peptide, 40-60 parts of glycidyl methacrylate, 0.03-0.11 parts of triethylamine, and 0.005-0.0125 parts of p-methoxyphenol were dispersed in 50-200 parts of N,N-dimethylformamide and reacted at 0-60℃ for 0.5-8 h to obtain peptide-modified acrylate.

[0017] In some of the above embodiments, a method for preparing peptide-modified acrylate is specifically described. By using appropriate solvents and reaction conditions, efficient grafting can be achieved, which helps to obtain laser coatings with good weather resistance.

[0018] In some embodiments, the modified core-shell filler is obtained by reacting cerium dioxide with tetraethoxysilane, and the average particle size of the cerium dioxide particles is 10~100nm.

[0019] In some of the above embodiments, the modified core-shell filler is formed by the hydrolysis-condensation reaction of cerium dioxide and tetraethoxysilane to form a silicon-oxygen network structure. The tetraethoxysilane forms a silicon layer on the particle surface, which is beneficial to improving the dispersion stability of cerium dioxide in the system. Controlling the average particle size of cerium dioxide to 10~100nm can reduce its scattering effect on visible light. Combined with the refractive index transition effect of the outer silicon dioxide shell, it reduces the interference on the light transmittance of the coating to a certain extent. Furthermore, the appropriate particle size range helps to reduce the tendency of agglomeration and improve the uniformity of the coating.

[0020] In some embodiments, the surface of the silica shell is further grafted with ureapropyltriethoxysilane and phenyltriethoxysilane.

[0021] In some of the above embodiments, the modified core-shell filler has a hierarchical structure of CeO2 core, SiO2 shell, and bissilane grafted layer. The SiO2 shell provides relatively stable grafting sites for ureapropyltriethoxysilane and phenyltriethoxysilane, promoting efficient anchoring of bissilane and forming a functionalized interface layer. Ureapropyltriethoxysilane and phenyltriethoxysilane are grafted onto the surface of the SiO2 shell layer through hydrolysis and condensation. The two can jointly improve the interfacial bonding force between the core-shell filler and the organic matrix and inhibit interfacial debonding.

[0022] This modified core-shell filler and peptide-modified acrylate can form a multi-dimensional synergistic effect, jointly improving the coating's weather resistance from two dimensions: physical protection and interface strengthening. On the one hand, the physical barrier of the SiO2 shell, the flexible buffer of the bissilane graft layer, and the hydrogen bond network constructed by the peptide can form multiple barriers, delaying the penetration of aging factors. On the other hand, the urea groups of ureapropyltriethoxysilane may form a hydrogen bond network with a certain strength and density with the amide bonds and hydroxyl groups in the peptide-modified acrylate, improving the interfacial bonding force between the filler and the resin matrix. This hydrogen bond network intertwines and connects with the dynamic hydrogen bond network of the peptide itself, which can enhance the stress transmission and dissipation efficiency of the filler-matrix interface and help suppress the generation of microcracks at the interface. Phenylacetoxysilane can improve the compatibility and dispersion stability of the filler in the hydrophobic polymer environment and suppress performance defects and light scattering phenomena caused by filler agglomeration.

[0023] In some embodiments, the preparation method of the modified core-shell packing includes the following steps:

[0024] M1: Cerium dioxide is reacted with tetraethoxysilane in a sol-gel reaction to form a silica shell on the surface of cerium dioxide, resulting in CeO2@SiO2;

[0025] M2: CeO2@SiO2 is grafted with ureapropyltriethoxysilane and phenyltriethoxysilane to obtain modified core-shell fillers.

[0026] In some of the above embodiments, a silicon dioxide layer is formed on the surface of cerium dioxide to achieve physical isolation of the cerium dioxide core, improve dispersion stability, and provide subsequent grafting sites; in the grafting reaction, the silicon dioxide surface reacts with ureapropyltriethoxysilane and phenyltriethoxysilane to form relatively stable Si-O-Si bonds, thereby improving the interfacial bonding of the core-shell filler.

[0027] In some embodiments, in step M2, the mass ratio of ureapropyltriethoxysilane to phenyltriethoxysilane is 4:2~3.

[0028] In some of the above embodiments, the mass ratio of ureapropyltriethoxysilane to phenyltriethoxysilane is controlled at 4:2~3. At this ratio, the urea groups are more fully bonded to the active groups of the resin, which can ensure the interfacial bonding strength. The phenyl groups form a moderate hydrophobic barrier to suppress steric hindrance or embrittlement caused by excessive ureapropyltriethoxysilane. On the other hand, due to the difference in condensation rates between ureapropyltriethoxysilane and phenyltriethoxysilane, this ratio may cause the grafted layer to form a gradient structure in which the inner layer tends to be dense with ureapropyl groups and the outer layer tends to be distributed with phenyl groups. This can promote the polar bonding force with the peptide-modified acrylate and improve the compatibility with the acrylic resin.

[0029] In some embodiments, the preparation method of the modified core-shell packing includes the following steps:

[0030] M1: Disperse 40 parts of cerium dioxide and 10-50 parts of tetraethoxysilane in 100-400 parts of ethanol-water solution, adjust the pH to 3-4, and react at 10-30℃ for 1-5 h to obtain CeO2@SiO2;

[0031] M2: Disperse 1.6 parts of ureapropyltriethoxysilane, 0.8-1.2 parts of phenyltriethoxysilane, and 20-60 parts of CeO2@SiO2 in 10-100 parts of ethanol-water solution, adjust the pH to 3-4, react for 10-60 min, adjust the pH to 5-6, and react at 20-80℃ for 2-6 h to obtain the modified core-shell filler.

[0032] In some of the above embodiments, the reaction conditions and dosage ratios of each step in the preparation method of the modified core-shell filler are specifically described. Under the condition of pH 3-4, the hydrolysis of silane and pre-adsorption on the particle surface can be promoted. Subsequently, adjusting the pH to 5-6 can accelerate the directional condensation of silane and surface silanol groups, achieving a strong bond. Urethyltriethoxysilane molecules have higher polarity and relatively small molecular volume. Their hydrolysis and condensation reaction rates are usually faster than those of phenyltriethoxysilane. Therefore, they are more likely to preferentially approach and adsorb onto the silica surface and undergo condensation reactions with surface silanol groups. Phenyltriethoxysilane, due to its large aromatic ring structure, has a relatively slow hydrolysis rate and greater steric hindrance. Under the condition of increased pH and accelerated condensation rate in the later stage of the reaction, it is more likely to condense with the remaining sites on the surface or through physical entanglement, tending to be distributed in the outer region of the grafted layer. Under these conditions, a modified core-shell filler with cerium dioxide as the core, silica as the shell, and urethyltriethoxysilane and phenyltriethoxysilane grafted onto the shell layer can be prepared.

[0033] In some embodiments, the polypeptide comprises an aliphatic tripeptide chain, wherein the aliphatic tripeptide chain comprises a glycine tripeptide.

[0034] In some of the above embodiments, the amino acid side groups of the aliphatic tripeptide chain do not contain aromatic ring structures, and generally exhibit better photostability and chain segment flexibility, which is conducive to the formation of a dynamically reversible hydrogen bond network in the polymer matrix, thereby improving the stress dissipation capacity of the film and inhibiting the generation of microcracks. The side chain of glycine consists only of hydrogen atoms, and its tripeptide chain segment has higher flexibility and rotational freedom. Its amino, carboxyl, and peptide bonds can form a relatively stable multi-point hydrogen bond network with the polar groups on the surface of the resin matrix and the modified core-shell filler, thereby enhancing interfacial bonding and improving the high light transmittance and long-term weather resistance stability of the laser coating.

[0035] In some embodiments, the photoinitiator includes at least one of TPO-L and Irgacure 1173. TPO-L has strong deep curing ability; Irgacure 1173 has a fast surface curing rate. Both have low yellowing properties, which can reduce the problem of coating aging and yellowing caused by initiator residue. As an example, the mass ratio of TPO-L and Irgacure 1173 is set to 1:1.

[0036] In some embodiments, the leveling agent includes at least one of BYK-333 and BYK-306. BYK-333 and BYK-306 can reduce the surface tension of the system and improve the wetting effect of the resin on the substrate.

[0037] Secondly, a laser film, characterized in that it comprises:

[0038] Provide raw materials for the laser coating according to any embodiment of the first aspect, and mix and degas the raw materials in a mass ratio to obtain the laser coating;

[0039] The laser coating is applied to the surface of the base film, and then laser embossed and UV cured.

[0040] According to this application, by mixing the raw materials of the laser coating and vacuum degassing, the components are uniformly dispersed and the air bubbles are removed to obtain the laser coating. Subsequently, a wet film is formed by coating, and laser imprinting is performed using a template. Finally, the laser coating is cured and formed by ultraviolet light-induced rapid free radical polymerization. The resulting laser film has good weather resistance.

[0041] Compared with the prior art, the beneficial effects of this application are at least as follows:

[0042] 1. This application uses a ring-opening grafting reaction to covalently bond polypeptide chains to an acrylate backbone to form polypeptide-modified acrylate. The introduced polypeptide segments can form hydrogen bond interactions with the polar groups in hydroxyethyl acrylate and polydipentaerythritol hexaacrylate. During the photocuring process, the polypeptide-modified acrylate, hydroxyethyl acrylate, and polydipentaerythritol hexaacrylate can construct a three-dimensional covalent cross-linked network. At the same time, the polypeptide segments participate in the formation of a hydrogen bond network structure with dynamic and reversible characteristics, which helps to improve the weather resistance of the laser coating.

[0043] 2. The modified core-shell filler designed in this application can form a multi-dimensional synergy with the composite acrylate. Through interfacial interaction, it can enhance the dispersion stability of the filler and improve the density and anti-aging medium penetration ability of the laser coating. Detailed Implementation

[0044] The various embodiments or implementation schemes in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments.

[0045] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0046] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0047] In this specification, unless otherwise specified, "parts" refers to "parts by weight".

[0048] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0049] Glycidyl methacrylate: CAS No. 106-91-2;

[0050] Hydroxyethyl acrylate: CAS number 818-61-1;

[0051] Polydipentaerythritol hexaacrylate: CAS No. 29570-58-9;

[0052] Glycine tripeptide: CAS number 556-33-2, sourced from Hubei Weideli Chemical Technology Co., Ltd.;

[0053] Cerium dioxide particles: average particle size is 50 nm;

[0054] Tetraethoxysilane: CAS number 78-10-4;

[0055] Ureapropyltriethoxysilane: CAS No. 23779-32-0;

[0056] Phenylacetoxysilane: CAS number 780-69-8.

[0057] Preparation Example 1

[0058] Preparation of peptide-modified acrylates

[0059] Under a nitrogen atmosphere, 10 parts of glycine tripeptide were dissolved in 100 parts of N,N-dimethylformamide to obtain a polypeptide solution. Then, 54 parts of glycidyl methacrylate, 0.1 parts of triethylamine, and 0.01 parts of p-methoxyphenol were added and mixed. The mixture was reacted at 5°C for 30 min and then at 40°C for 4 h. DMF was removed in a thin-film evaporator (80°C, 1 mbar). The product was then centrifuged, washed, filtered, and dried to obtain the polypeptide-modified acrylate.

[0060] Preparation Example 2

[0061] Preparation of modified core-shell fillers:

[0062] M1: 40 parts of cerium dioxide were dispersed in 150 parts of ethanol-water solution (120 parts of anhydrous ethanol and 30 parts of deionized water), and the pH was adjusted to 3.5 with 0.1M acetic acid. 30 parts of tetraethoxysilane were dispersed in 50 parts of ethanol and added to the solution containing cerium dioxide. The mixture was reacted at 25°C for 4 hours, centrifuged, washed, and vacuum dried to obtain CeO2@SiO2.

[0063] M2: 40 parts CeO2@SiO2, 1.6 parts ureapropyltriethoxysilane, and 1 part phenyltriethoxysilane were dispersed in 100 parts ethanol-water solution (90 parts anhydrous ethanol and 10 parts deionized water). The pH was adjusted to 3.5 with 0.1M acetic acid and stirred for 30 min. Then, the pH was adjusted to 5.5 with 0.5 wt% ammonia. The mixture was reacted at 50℃ for 4 h. After centrifugation, washing, and drying, modified core-shell packing A was obtained.

[0064] Preparation Example 3

[0065] Preparation of modified core-shell fillers:

[0066] M1: 40 parts of cerium dioxide were dispersed in 150 parts of ethanol-water solution (120 parts of anhydrous ethanol and 30 parts of deionized water), and the pH was adjusted to 3.5 with 0.1M acetic acid. 30 parts of tetraethoxysilane were dispersed in 50 parts of ethanol and added to the solution containing cerium dioxide. 0.8 parts of hexadecyltrimethylammonium bromide were added, and the mixture was reacted at 25°C for 4 hours. After centrifugation, washing, and vacuum drying, modified core-shell filler B was obtained.

[0067] Preparation Example 4

[0068] Preparation of modified core-shell fillers:

[0069] M1: 40 parts of cerium dioxide were dispersed in 150 parts of ethanol-water solution (120 parts of anhydrous ethanol and 30 parts of deionized water), and the pH was adjusted to 3.5 with 0.1M acetic acid. 30 parts of tetraethoxysilane were dispersed in 50 parts of ethanol and added to the solution containing cerium dioxide. 0.8 parts of hexadecyltrimethylammonium bromide were added, and the mixture was reacted at 25°C for 4 hours. After centrifugation, washing, and vacuum drying, CeO2@SiO2 was obtained.

[0070] M2: 40 parts CeO2@SiO2, 2.08 parts ureapropyltriethoxysilane, and 0.52 parts phenyltriethoxysilane were dispersed in 100 parts ethanol-water solution (90 parts anhydrous ethanol and 10 parts deionized water). The pH was adjusted to 3.5 with 0.1M acetic acid and stirred for 30 min. Then, the pH was adjusted to 5.5 with 0.5wt% ammonia water and reacted at 50℃ for 4 h. After centrifugation, washing, and drying, the modified core-shell filler C was obtained.

[0071] Preparation Example 5

[0072] Preparation of modified core-shell fillers:

[0073] M1: 40 parts of cerium dioxide were dispersed in 150 parts of ethanol-water solution (120 parts of anhydrous ethanol and 30 parts of deionized water), and the pH was adjusted to 3.5 with 0.1M acetic acid. 30 parts of tetraethoxysilane were dispersed in 50 parts of ethanol and added to the solution containing cerium dioxide. 0.8 parts of hexadecyltrimethylammonium bromide were added, and the mixture was reacted at 25°C for 4 hours. After centrifugation, washing, and vacuum drying, CeO2@SiO2 was obtained.

[0074] M2: 40 parts CeO2@SiO2, 1.3 parts ureapropyltriethoxysilane, and 1.3 parts phenyltriethoxysilane were dispersed in 100 parts ethanol-water solution (90 parts anhydrous ethanol and 10 parts deionized water). The pH was adjusted to 3.5 with 0.1M acetic acid and stirred for 30 min. Then, the pH was adjusted to 5.5 with 0.5wt% ammonia. The reaction was carried out at 50℃ for 4 h. After centrifugation, washing, and drying, the modified core-shell filler D was obtained.

[0075] Example 1

[0076] Preparation of laser coatings:

[0077] 40 parts of peptide-modified acrylate, 35 parts of hydroxyethyl acrylate, 40 parts of polydipentaerythritol hexaacrylate, 8 parts of modified core-shell filler A, 2.3 parts of TPO-L, 2.3 parts of Irgacure 1173, and 0.4 parts of BYK-333 were placed in a stirrer and stirred evenly. Then, the mixture was placed under vacuum for degassing for 30 minutes to obtain the laser coating.

[0078] Example 2

[0079] Preparation of laser coatings:

[0080] 40 parts of peptide-modified acrylate, 10 parts of hydroxyethyl acrylate, 65 parts of polydipentaerythritol hexaacrylate, 8 parts of modified core-shell filler A, 2.3 parts of TPO-L, 2.3 parts of Irgacure 1173, and 0.4 parts of BYK-333 were placed in a stirrer and stirred evenly. Then, the mixture was placed under vacuum for degassing for 30 minutes to obtain the laser coating.

[0081] Example 3

[0082] Preparation of laser coatings:

[0083] 40 parts of peptide-modified acrylate, 50 parts of hydroxyethyl acrylate, 25 parts of polydipentaerythritol hexaacrylate, 8 parts of modified core-shell filler A, 2.3 parts of TPO-L, 2.3 parts of Irgacure 1173, and 0.4 parts of BYK-333 were placed in a stirrer and stirred evenly. Then, the mixture was placed under vacuum for degassing for 30 minutes to obtain the laser coating.

[0084] Example 4

[0085] Preparation of laser coatings:

[0086] It is largely the same as Example 1, except that the modified core-shell packing A is replaced with modified core-shell packing B.

[0087] Example 5

[0088] Preparation of laser coatings:

[0089] It is largely the same as Example 1, except that the modified core-shell packing A is replaced with modified core-shell packing C.

[0090] Example 6

[0091] Preparation of laser coatings:

[0092] It is largely the same as Example 1, except that the modified core-shell packing A is replaced with the modified core-shell packing D.

[0093] Comparative Example 1

[0094] Preparation of laser coatings:

[0095] It is largely the same as Example 1, except that the peptide-modified acrylate is replaced with glycidyl methacrylate.

[0096] Comparative Example 2

[0097] Preparation of laser coatings:

[0098] Similar to Example 1, except that hydroxyethyl acrylate was not added. Specifically, the difference is as follows:

[0099] S1: Place 57.5 parts of peptide-modified acrylate, 57.5 parts of polydipentaerythritol hexaacrylate, 8 parts of modified core-shell filler A, 2.3 parts of TPO-L, 2.3 parts of Irgacure 1173, and 0.4 parts of BYK-333 in a stirrer, stir evenly, and then place under vacuum conditions for degassing for 30 minutes to obtain the laser coating.

[0100] Comparative Example 3

[0101] Preparation of laser coatings:

[0102] Similar to Example 1, except that polydipentaerythritol hexaacrylate was not added. Specifically, the difference is as follows:

[0103] S1: 61.4 parts of peptide-modified acrylate, 53.6 parts of hydroxyethyl acrylate, 8 parts of modified core-shell filler A, 2.3 parts of TPO-L, 2.3 parts of Irgacure 1173, and 0.4 parts of BYK-333 were placed in a stirrer and stirred evenly. Then, the mixture was placed under vacuum for 30 minutes to remove bubbles, thus obtaining the laser coating.

[0104] Comparative Example 4

[0105] Preparation of laser coatings:

[0106] It is largely the same as Example 1, except that the modified core-shell filler A is replaced with cerium dioxide particles.

[0107] Test section

[0108] The laser coatings prepared in the examples and comparative examples were applied to the surface of a PET release film with a thickness of approximately 50 μm. The film thickness was controlled to be approximately 10 μm. Imprinting was performed using a 100 LPI laser grating nickel template with a depth of 0.5 μm. The imprinting temperature was 85°C, the pressure was 1 MPa, and the holding time was 6 s. Immediately after imprinting, the film was cured by irradiation with 365 nm ultraviolet light (irradiance 200 mW / cm²). 2 (Cure time 12s) to obtain a laser film, and then conduct performance tests.

[0109] Transmittance test: The prepared laser film was cut into 50mm×50mm samples, and the transmittance T0 (%) was tested according to the national standard GB / T2410-2008 under the conditions of 25℃ and 50% relative humidity.

[0110] Tensile strength test: The prepared laser film was cut into dumbbell-shaped specimens with a length of 150 mm and a narrow parallel width of 10 mm. The tensile strength σ0 (MPa) was tested at a tensile rate of 50 mm / min, referring to the national standard GB / T1040-2006.

[0111] Thermal-UV aging test: The samples after transmittance testing were placed in a UV test chamber at a temperature of 55℃, using a UVA-340 light source with a spectral irradiance of 0.76 W / m² at 340 nm. 2 •nm, UV irradiation time is 1000h.

[0112] Yellowing resistance test: Referring to the national standard GB / T2409-1980, under the conditions of 25℃ and 50% relative humidity, the yellow index YI0 of the laser film before the heat-UV aging test and the yellow index YI1 after the heat-UV aging test are measured using a spectrophotometer. The change in yellow index ΔYI=YI1-YI0, and the higher the yellow index, the higher the degree of yellowing.

[0113] After the heat-UV aging test, the transmittance T1 (%) after aging was determined according to the above transmittance test method. The transmittance retention rate after heat-UV aging δ1 (%) = T1 / T0 × 100%;

[0114] After the heat-UV aging test, the tensile strength σ1 (MPa) after aging was determined according to the tensile strength test method described above, and the heat-UV aging tensile strength retention rate δ2 (%) was calculated as σ1 / σ0 × 100%.

[0115] The test results are shown in Table 1.

[0116] Table 1

[0117]

[0118] Table 1 shows that the laser films prepared from the laser coatings obtained in each example exhibit better heat-UV aging transmittance retention, tensile strength retention, and yellowing resistance compared to the comparative examples. This may be because Comparative Example 1 uses unmodified glycidyl methacrylate, and the lack of polypeptide chains results in a coating lacking a reversible hydrogen bond network, making it more prone to microcrack formation and propagation. Aging factors can easily spread through these cracks, accelerating oxidative yellowing and reducing weather resistance. Comparative Example 2 lacks hydroxyethyl acrylate to provide hydroxyl groups, leading to a decrease in the hydrogen bond network density in the laser coating. This weakens the bonding between the matrix and the modified core-shell filler, and the existing micro-gaps may allow aging media to easily penetrate. Furthermore, the absence of hydroxyethyl acrylate... Esters may cause the cross-linked network to be too rigid, making the laser coating more brittle after aging. In Comparative Example 3, no polydipentaerythritol hexaacrylate was added, and the cured network may be looser and the chain segments more fluid. The resin backbone is easily oxidized to generate chromophores when in contact with aging agents. The free radicals caused by aging may easily migrate within the laser coating, deteriorating the weather resistance. In Comparative Example 4, the modified core-shell filler was replaced with cerium dioxide particles. Cerium dioxide particles are prone to agglomeration and may interfere with light transmittance. The lack of silane grafting may lead to poor bonding between the filler and the resin, and interface debonding is likely to occur during aging. The interfacial gaps between the filler and the matrix can cause the aging medium to easily penetrate through the gaps, accelerating the aging of the laser coating.

[0119] As can be seen from Examples 1, 2, and 3, the mass ratio of peptide-modified acrylate, hydroxyethyl acrylate, and polydipentaerythritol hexaacrylate has a certain influence on the weather resistance of laser coatings. Preferably, when the mass ratio of peptide-modified acrylate, hydroxyethyl acrylate, and polydipentaerythritol hexaacrylate is controlled at 1:(0.8~0.9):(0.9~1), the synergistic effect of functional group reaction and the rigid-flexible balance of crosslinking network can be better achieved, and the coating formed by the laser coating has better weather resistance.

[0120] As can be seen from Examples 1, 4-6, the composite grafting modification of modified core-shell fillers with ureapropyltriethoxysilane and phenyltriethoxysilane has a certain impact on the weather resistance of the coating formed by laser coating. Furthermore, when the mass ratio of ureapropyltriethoxysilane to phenyltriethoxysilane is controlled at 4:2-3, the coating formed by laser coating has higher weather resistance.

[0121] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A laser coating for laser films, characterized in that, The raw materials include the following parts by weight: The composition includes 115 parts of composite acrylate, 5-10 parts of modified core-shell filler, 3-9 parts of photoinitiator, and 0.1-1 parts of leveling agent. The composite acrylate comprises peptide-modified acrylate, hydroxyethyl acrylate, and polydipentaerythritol hexaacrylate, wherein the mass ratio of peptide-modified acrylate, hydroxyethyl acrylate, and polydipentaerythritol hexaacrylate is 1:(0.7~1):(0.8~1.2). The peptide-modified acrylate is obtained by a ring-opening grafting reaction between the peptide and the epoxy acrylate, wherein the epoxy acrylate includes glycidyl methacrylate; the peptide includes an aliphatic tripeptide chain, wherein the aliphatic tripeptide chain includes a glycine tripeptide. The modified core-shell filler comprises a cerium dioxide core and a silicon dioxide shell.

2. The laser coating according to claim 1, characterized in that, The polypeptide-modified acrylate was prepared by the following method: Ten parts of peptide, 40-60 parts of glycidyl methacrylate, 0.03-0.11 parts of triethylamine, and 0.005-0.0125 parts of p-methoxyphenol were dispersed in 50-200 parts of N,N-dimethylformamide and reacted at 0-60℃ for 0.5-8 h to obtain peptide-modified acrylate.

3. The laser coating according to claim 1, characterized in that, The modified core-shell filler is obtained by reacting cerium dioxide with tetraethoxysilane, and the average particle size of the cerium dioxide particles is 10~100nm.

4. The laser coating according to claim 3, characterized in that, The modified core-shell filler surface is further grafted with ureapropyltriethoxysilane and phenyltriethoxysilane.

5. The laser coating according to claim 4, characterized in that, The preparation method of the modified core-shell packing includes the following steps: M1: Cerium dioxide is reacted with tetraethoxysilane in a sol-gel reaction to form a silica shell on the surface of cerium dioxide, resulting in CeO2@SiO2; M2: CeO2@SiO2 is grafted with ureapropyltriethoxysilane and phenyltriethoxysilane to obtain modified core-shell fillers.

6. The laser coating according to claim 5, characterized in that, In step M2, the mass ratio of ureapropyltriethoxysilane to phenyltriethoxysilane is 4:2~3.

7. The laser coating according to claim 6, characterized in that, The preparation method of the modified core-shell packing includes the following steps: M1: Disperse 40 parts of cerium dioxide and 10-50 parts of tetraethoxysilane in 100-400 parts of ethanol-water solution, adjust the pH to 3-4, and react at 10-30℃ for 1-5 h to obtain CeO2@SiO2; M2: Disperse 1.6 parts of ureapropyltriethoxysilane, 0.8-1.2 parts of phenyltriethoxysilane, and 20-60 parts of CeO2@SiO2 in 10-100 parts of ethanol-water solution, adjust the pH to 3-4, react for 10-60 min, adjust the pH to 5-6, and react at 20-80℃ for 2-6 h to obtain the modified core-shell filler.

8. The laser coating according to claim 1, characterized in that, The raw materials meet at least one of the following conditions: 1) The photoinitiator includes at least one of TPO-L and Irgacure 1173; 2) The leveling agent includes at least one of BYK-333 and BYK-306.

9. A laser film, characterized in that, include: Provide the raw materials for the laser coating according to any one of claims 1 to 8, and mix and degas the raw materials in proportions by weight to obtain the laser coating; The laser coating is applied to the surface of the base film, and then laser embossed and UV cured.

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