Anti-ultraviolet high-barrier transparent film and preparation method thereof

Abstract

The invention discloses an anti-ultraviolet high-barrier transparent film with a multi-layer structure and a preparation method of the anti-ultraviolet high-barrier transparent film. The composite film material comprises a barrier layer, a bonding layer, a middle layer and a heat sealing layer. Wherein the blocking layer is made of efficient blocking materials such as KPET and KNY, anti-ultraviolet particles are dispersed in the heat sealing layer, and the ultraviolet protection capacity is improved. The middle layer is of a reinforced film structure such as NY and PET, and the bonding layer ensures stable connection between the layers. In addition, the ink layer and the reflecting layer are introduced, two diarylethene films with different discoloration can be adopted, the photochromic property is achieved, attractiveness is improved, product interactivity is improved, ultraviolet rays are reflected after discoloration, the anti-ultraviolet high-barrier property is improved, and meanwhile the transparent effect is kept.

Description

Technical Field

[0001] The invention relates to the technical field of composite films, in particular to an anti-ultraviolet high-barrier transparent film for food packaging. Background Art

[0002] "PrePack" is an aseptic packaging, mostly used for dairy product packaging bags. Its structure is a multi-layer aseptic composite film, such as a three-layer black and white film, and there are also high-barrier multi-layer co-extruded films and aluminum-plastic composite films. This type of composite film can effectively block the influence of external factors such as oxygen and moisture on food quality, thereby extending the shelf life of food. In order to allow consumers to intuitively see the state of the food in the package, there is now a demand for transparent food packaging. However, transparent packaging bags cannot block ultraviolet rays, and ultraviolet radiation can easily cause the degradation of photosensitive components such as vitamins in food, oxidize fat substances to make them rancid and deteriorate, etc., affecting the flavor and taste of food. Therefore, it is necessary to design and manufacture a high-barrier transparent film that is resistant to ultraviolet rays. In the prior art, PET is used as a transparent substrate, and an anti-ultraviolet additive is added therein to achieve the anti-ultraviolet function, but this type of technical solution has limited blocking effect on ultraviolet light, and can only guarantee a better blocking effect in the range of 200~360nm, while the barrier performance for water and oxygen is poor, OTR≤120, WTR≤15. Summary of the invention

[0003] The main purpose of the present invention is to overcome the shortcomings of the prior art, provide an anti-ultraviolet high-barrier transparent film, and improve the wavelength range of ultraviolet light blocked by food packaging materials; the secondary purpose is to provide an improved synthesis method of diarylethene and prepare a diarylethene film material.

[0004] To achieve the above purpose, the technical solution provided by the present invention is as follows: An anti-ultraviolet high-barrier transparent film, which is arranged from the outside to the inside in sequence and includes: The barrier layer includes a K modified film, AlO x Modified membrane, SiO2 modified membrane; Adhesive layer, the adhesive layer is made by coating and compounding a transparent and boiling-resistant adhesive; An intermediate layer, wherein the intermediate layer is a functional film layer; A reflective layer, wherein the reflective layer is a diarylethene film (A); The heat sealing layer is a PP or PE film with UV-resistant particles evenly dispersed therein. The bottom of the barrier layer is glued to the middle layer through an adhesive layer, and the middle layer, the reflective layer and the heat-sealing layer are heat-sealed and bonded.

[0005] Furthermore, the barrier layer includes KPET, KNY, PET-AlO xBOPP-AlO x , PET-SiO2 Furthermore, the middle layer includes at least one of NY, PET, BOPE and MDOPE.

[0006] Furthermore, the thickness ratio of the barrier layer / adhesive layer / intermediate layer / reflective layer / heat-sealing layer is: (0.75~1.25) / (0.5~1) / (1.5~2) / (1.5~3) / (1.5~2).

[0007] Furthermore, the adhesive layer is one of water-boiling grade glue, semi-high temperature cooking grade glue, and high temperature cooking grade glue.

[0008] Furthermore, an ink layer is provided between the barrier layer and the adhesive layer, the barrier layer at least partially covers the ink layer, and the ink layer is glued to one side of the barrier layer through the adhesive layer.

[0009] Furthermore, the ink layer is a diarylethene film (B), and the diarylethene film (A) and the diarylethene film (B) are any two of a red light-changeable diarylethene film, a blue light-changeable diarylethene film, and a purple light-changeable diarylethene film.

[0010] A method for preparing a diarylethene film comprises the following steps: S1, weigh 5-20 parts of a diarylethene photochromic compound, 150-200 parts of an ethyl acetate-water solution having a volume fraction of 75-85%, and 1-5 parts of a surfactant, and stir and mix them evenly; S2, heating the mixture obtained in S1 to 40-60 degrees Celsius and keeping the temperature for 1-2 hours to prepare an active intermediate; S3, coating the active intermediate obtained in S2 onto the surface of at least one of the adjacent layers, and drying at 60-80 degrees Celsius.

[0011] Further, the diarylethene photochromic compound includes: 2,3-Bis(2,4,5-trimethyl-3-thienyl)maleic anhydride, 2,3-Bis(2,4,5-trimethyl-3-thienyl)maleimide, At least one of cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethylene.

[0012] Furthermore, in S3, the surface of the intermediate layer and / or the heat-sealing layer is pretreated, and the pretreatment includes: heat-insulating and activating the intermediate layer and / or the heat-sealing layer at 40-50°C.

[0013] Furthermore, the light transmittance of the diarylethene film is greater than 95%, and the haze is less than 5%.

[0014] The advantages and beneficial effects of the present invention are: 1. High-efficiency barrier and UV resistance: Through the specially selected barrier layer, high-efficiency barrier to external environmental factors, including oxygen, moisture, etc. is achieved. At the same time, the UV-resistant particles evenly dispersed in the heat-sealing layer can effectively resist the damage of ultraviolet rays and protect the contents of the package from damage caused by ultraviolet rays.

[0015] 2. Composite structure and function: The bonding layer tightly combines the functional layers, which not only ensures the overall stability of the membrane structure, but also realizes the effective superposition of the functions of each layer. The selection of the middle layer enhances the mechanical properties and durability of the membrane.

[0016] 3. Weather resistance and aesthetics: The setting of the ink layer not only provides a rich visual effect for the packaging, but also enhances the brand recognition of the product. At the same time, the close combination between the ink layer and the barrier layer ensures the durability and weather resistance of the printed pattern.

[0017] 4. Intelligent color-changing function: The transparent diarylethene film (A) and diarylethene film (B) used in the reflective layer and the ink layer have photosensitive color-changing properties and can present different colors under ultraviolet light. When the reflective layer turns blue or purple under ultraviolet light, its surface reflects blue and purple light, further improving the anti-ultraviolet technical effect. At the same time, the ink layer turns red without affecting the visual effect of the ink layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the present invention; In the figure: 1- barrier layer, 2- ink layer, 3- adhesive layer, 4- intermediate layer, 5- reflective layer, 6- heat seal layer. DETAILED DESCRIPTION

[0019] OTR stands for oxygen transmission rate, which refers to the rate at which a material or package transmits oxygen. It is often used to measure the oxygen barrier properties of a material or package.

[0020] WTR stands for water vapor transmission rate, which refers to the rate at which a material or package transmits water vapor.

[0021] PE: Polyethylene film.

[0022] PP: Polypropylene film.

[0023] BOPE: Biaxially oriented polyethylene film.

[0024] MDOPE: longitudinally oriented polyethylene film.

[0025] KPET: Based on PET (polyethylene terephthalate), the prefix K indicates a plastic film coated on one side with high barrier PVDC (polyvinylidene chloride).

[0026] KNY: Based on NY (polyamide, nylon), the prefix K indicates a plastic film coated on one side with high barrier PVDC (polyvinylidene chloride).

[0027] PET-AlOx: PET is used as the substrate, aluminum oxide is vacuum evaporated on the corona-treated side of PET, and the other side is a plastic film that is not corona-treated.

[0028] PET-SiO2: A composite film made of PET as the base material and nano-silicon dioxide added during the PET melting preparation process.

[0029] BOPP-AlO x : Using BOPP (biaxially oriented polypropylene film) as the substrate, vacuum evaporation of aluminum oxide on the BOPP corona-treated side, and the other side is a plastic film that is not corona-treated. In the corresponding embodiment of the present invention, the side of the K-modified film coated with PVDC is the side away from the adhesive layer.

[0030] In the corresponding embodiment of the present invention, AlO x The corona treated surfaces of the modified films are all composited with the adhesive layer.

[0031] GB / T 10004 stipulates that packaging is divided into four grades according to the use temperature: ordinary grade (≤80℃), boiling grade (above 80℃~100℃), semi-high temperature cooking grade (above 100℃~121℃), and high temperature cooking grade (above 121℃~145℃).

[0032] Diarylethenes are a class of photochromic materials that change color under certain lighting conditions. Generally, diarylethenes change from a colorless or light-colored state to a darker state, such as blue, purple, or red, when exposed to ultraviolet light. This color change is usually reversible, meaning that the material can return to its original colorless or light-colored state under another lighting condition or heat.

[0033] Barrier layer: The barrier layer can be made of K modified film, AlO x Modified film and SiO2 modified film. These materials have high barrier properties and can effectively block oxygen, water vapor and ultraviolet rays, protecting the inner layer materials from the influence of the external environment.

[0034] Adhesive layer: The adhesive layer uses a transparent, retort-resistant adhesive to ensure a strong bond between the barrier layer and the middle layer. This adhesive can not only withstand the high temperature and high pressure during the retort process, but also maintain the transparency of the film without affecting the overall visual effect.

[0035] Intermediate layer: The intermediate layer is a functional film layer, which can be a material with specific functions, such as enhancing the mechanical strength of the film, providing additional barrier properties or adding specific optical effects. The key point is: the intermediate layer avoids the direct contact between the adhesive layer and the reflective layer, but is optional, so that the reflective layer can be coated on the intermediate layer and the heat-sealing layer at the same time, so that the thickness of the reflective layer can reach a certain standard to achieve better reflective function. It should be understood that the ink layer can optionally add a reflective effect, and can also be printed using conventional technology to obtain the existing technical effect without intelligent color change. The heat-sealed bonding between the intermediate layer and the barrier layer, the reflective layer and the heat-sealing layer ensures the close connection between the layers and improves the overall performance of the film.

[0036] Reflective layer: The reflective layer is obtained by coating and drying the ethyl acetate solution of diarylethene. It is worth noting that the use of a certain volume fraction of ethyl acetate-water solution to disperse diarylethene, on the one hand, utilizes the characteristic of ethyl acetate being easy to volatilize, which is convenient for subsequent coating and drying. On the other hand, ethyl acetate, as a solvent with low polarity, is compounded with deionized water as a solvent, so that diarylethene is enriched at the interface of ethyl acetate-water, which is more conducive to the stirring and dispersion of diarylethene with a larger molecular structure, and ensures that the reflective layer has the ability to reflect light of a specific wavelength while reducing the haze that may be caused under non-illumination conditions, thereby achieving a specific color effect while maintaining the transparent property. The heat-sealed bonding between the reflective layer and the intermediate layer and the heat-sealing layer ensures the stability of the reflective layer and the durability of the function. The present invention also provides a method for preparing a diarylethene film, wherein the diarylethene is dispersed by an ethyl acetate solution and a surfactant, and then heat-insulated, and heat-insulated and activated to form a stable active intermediate, and the active intermediate is coated on the surface of at least one of the adjacent layers, such as the intermediate layer and / or the heat-sealing layer, and dried at 60 to 80 degrees Celsius. The coating process ensures the uniform distribution of the active intermediates, and the drying process helps to form a stable film structure. The use of ethyl acetate solution combined with surfactants can not only achieve uniform dispersion of diarylethenes, but also facilitate subsequent drying and removal. The most prominent function of the reflective layer structure is that it fully utilizes the reflective characteristics of the optical film to block a portion of ultraviolet rays and light within a certain visible wavelength range by reflection, thereby reducing the problem of ultraviolet rays penetrating the subsequent film layer to irradiate food and extend the packaging life. Furthermore, the brighter the color displayed by the photoluminescence, the more intuitive it can be to remind the salesperson or customer that the food is being exposed to ultraviolet rays so that it can be shielded.

[0037] Heat sealing layer: The heat sealing layer is a PP or PE film with UV-resistant particles evenly dispersed, which not only provides good heat sealing performance, but also enhances the film's UV resistance. The addition of UV-resistant particles can be used as the last barrier to absorb or reflect UV rays, protecting the internal structure of the film from UV damage.

[0038] Ink layer: The ink layer is a diarylethene film (B), which forms a red, blue or purple color change effect with the diarylethene film (A) of the reflective layer, increasing the visual appeal and functionality of the film. The ink layer is bonded to one side of the barrier layer through an adhesive layer to ensure the stability of the ink layer and the durability of the color. The synergistic effect of each layer of material ensures that the UV-resistant high-barrier transparent film has excellent performance in barrier properties, transparency, cooking resistance, heat sealing performance and UV resistance, and is suitable for a variety of application scenarios that require high barrier and UV protection.

[0039] The structural design of the above-mentioned UV-resistant high-barrier transparent film not only reflects the synergistic effect of each layer of material, but also takes into account the influence of optical principles on transparency. The design and selection of the thickness of each layer are crucial to maintaining the high transparency of the film. Appropriate thickness can reduce the multiple reflections and scattering of light inside the material, thereby improving transparency. Specifically, a barrier layer that is too thick will increase the scattering and absorption of light and reduce transparency; a layer that is too thin may reduce the barrier performance. The thickness of the adhesive layer needs to be thin enough to reduce the reflection of light at the interface between the layers, avoid the formation of multiple reflections and interference of light, and thus maintain the high transparency of the film. At the same time, the adhesive layer needs to have sufficient strength to ensure a strong bond between the layers. The thickness of the intermediate layer needs to balance functionality and transparency. A layer that is too thick may introduce additional light scattering and affect transparency; a layer that is too thin may not provide sufficient functional performance. The reflective layer must be matched with an appropriate thickness to achieve the ideal smart reflection effect, and it will also have a negative impact on transparency. Similarly, the UV-resistant particles in the heat-sealing layer will increase the scattering of light and reduce transparency. The thickness ratio of each layer of material is based on optical principles and aims to balance barrier properties, functionality and transparency. The best performance is ultimately achieved by controlling the combined thickness of each layer.

[0040] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0041] Examples 1 to 5 are composite preparation methods of diarylethene membrane (A), wherein a certain volume fraction of ethyl acetate is used, and the remainder includes acetic acid, ethanol, and water formed by acetic acid-ethanol esterification reaction.

[0042] Example 1 A method for preparing a diarylethene film comprises the following steps: S1, weigh 2,3-bis(2,4,5-trimethyl-3-thienyl)maleic anhydride in parts by weight. 5 parts, 200 parts of ethyl acetate with a volume fraction of 75%, and 1 part of surfactant are stirred and mixed; S2, heating the mixture obtained in S1 to 45 degrees Celsius and keeping it warm for 1 hour to prepare an active intermediate; S3, coating the active intermediate obtained in S2 onto the surface of the intermediate layer and drying it at 80 degrees Celsius to obtain an intermediate layer / reflective layer structure film.

[0043] Example 2 A method for preparing a diarylethene film comprises the following steps: S1, weigh 2,3-bis(2,4,5-trimethyl-3-thienyl)maleimide, 10 parts, 180 parts of 75% by volume ethyl acetate, and 3 parts of surfactant were stirred and mixed; S2, heating the mixture obtained in S1 to 60 degrees Celsius and keeping it warm for 2 hours to prepare an active intermediate; S3, after activating the middle layer and the heat sealing layer at 50°C for 1 hour, the active intermediate obtained in S2 is coated on the surface of the middle layer and the heat sealing layer, and dried at 60°C; an middle layer / reflective layer / heat sealing layer structure film is obtained.

[0044] Example 3 A method for preparing a diarylethene film comprises the following steps: S1, weigh 20 parts by weight of cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethylene, 150-200 parts by volume of 85% ethyl acetate, and 5 parts by volume of a surfactant, and stir and mix them; S2, heating the mixture obtained in S1 to 40 degrees Celsius and keeping it warm for 2 hours to prepare an active intermediate; S3, after activating the intermediate layer and the heat-sealing layer at 60°C for 1 hour, the active intermediate obtained in S2 is coated on the surface of the heat-sealing layer and dried at 75°C; a structure film of the intermediate layer / reflective layer / heat-sealing layer is obtained.

[0045] Example 4 A method for preparing a diarylethene film comprises the following steps: S1, weigh 10 parts by weight of 2,3-bis(2,4,5-trimethyl-3-thienyl)maleic anhydride, 10 parts of 2,3-bis(2,4,5-trimethyl-3-thienyl)maleimide, 150-200 parts of ethyl acetate with a volume fraction of 75%, and 1-5 parts of a surfactant, and stir and mix them; S2, heating the mixture obtained in S1 to 60 degrees Celsius and keeping it warm for 1 hour to prepare an active intermediate; S3, after activating the middle layer and the heat sealing layer at 50°C for 2 hours, the active intermediate obtained in S2 is coated on the surface of the middle layer and the heat sealing layer, and dried at 80°C; an middle layer / reflective layer / heat sealing layer structure film is obtained.

[0046] Example 5 A method for preparing a diarylethene film comprises the following steps: S1, weigh 5 parts of 2,3-bis(2,4,5-trimethyl-3-thienyl)maleimide, 10 parts of cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethylene, 150-200 parts of ethyl acetate with a volume fraction of 75%, and 1-5 parts of a surfactant, and stir and mix them; S2, heating the mixture obtained in S1 to 60 degrees Celsius and keeping it warm for 1.5 hours to prepare an active intermediate; S3, after activating the intermediate layer and the heat-sealing layer at 45°C for 2 hours, the active intermediate obtained in S2 is coated on the surface of the intermediate layer and / or the heat-sealing layer, and dried at 75°C; and an intermediate layer / reflective layer / heat-sealing layer structure film is obtained.

[0047] Examples 6 to 10 are composite preparation methods of diarylethene film (A). Example 6 The only difference from Example 1 is that: 20 parts of ink are also mixed in S1, and S3 is to apply the active intermediate obtained in S2 to the surface of the barrier layer and dry it at 80 degrees Celsius to obtain a barrier layer / ink layer structure film.

[0048] Example 7 The only difference from Example 2 is that: 25 parts of ink are also mixed in S1, and S3 is that after the barrier layer is activated at 50°C for 1 hour, the active intermediate obtained in S2 is coated on the surface of the barrier layer and dried at 60°C; a barrier layer / ink layer structure film is obtained.

[0049] Example 8 The only difference from Example 3 is that: 30 parts of ink are also mixed in S1, and S3 is that after the barrier layer is activated at 60°C for 1 hour, the active intermediate obtained in S2 is coated on the surface of the barrier layer and dried at 75°C; a barrier layer / ink layer structure film is obtained.

[0050] Example 9 The only difference from Example 4 is that: 25 parts of ink are also mixed in S1, and S3 is that after the barrier layer is activated at 50°C for 2 hours, the active intermediate obtained in S2 is coated on the surface of the barrier layer and dried at 80°C; a barrier layer / ink layer structure film is obtained.

[0051] Example 10 The only difference from Example 5 is that: 25 parts of ink are also mixed in S1, and S3 is that after the barrier layer is activated at 45°C for 2 hours, the active intermediate obtained in S2 is coated on the surface of the barrier layer and dried at 75°C; a barrier layer / ink layer structure film is obtained.

[0052] Examples 11 to 25 are structures of UV-resistant high-barrier transparent films: wherein the PP or PE in the heat-sealing layer of each example contains UV-resistant particles, and the UV-resistant particles can preferably be one or a combination of hydroxybenzophenone, hydroxyphenyl-S-triazine, 2-benzotriazole, titanium dioxide, zinc oxide, polyphenols, vitamins, carotenoids, hindered phenols and phosphites. The UV-resistant particles are blended with PP / PE and extruded and blown into a film, and then coated with a reflective layer and / or an intermediate layer, and then hot-pressed and laminated at 50~70°C and 0.4~1MPa. The ink layer is directly coated on the surface of the barrier layer, dried at 60°C for more than 2h to be shaped, and then bonded to the intermediate layer through an adhesive layer.

[0053] Embodiment 11 KPET / Example 6 / water-boiled grade adhesive layer / PET / Example 1 / PP, thicknesses are: 21μm / 45μm / 20μm / 34μm / 62μm / 38μm, wherein the heat sealing layer PP is blended and dispersed with 10% by mass hydroxybenzophenone.

[0054] Example 12 KPET / Example 7 / semi-high temperature cooking grade adhesive layer / PET / Example 2 / PP, thicknesses are: 22μm / 52μm / 10μm / 42μm / 42μm / 37μm, wherein the heat sealing layer PP is blended and dispersed with 5% by mass hydroxyphenyl-S-triazine.

[0055] Embodiment 13 KPET / Example 10 / high temperature cooking grade adhesive layer / BOPE / Example 4 / PE, thicknesses are as follows: 20μm / 37μm / 15μm / 33μm / 45μm / 38μm, wherein the heat sealing layer PE is blended and dispersed with 5% by mass 2-benzotriazole.

[0056] Embodiment 14 KNY / Example 6 / semi-high temperature cooking grade adhesive layer / MDOPE / Example 2 / PP, thicknesses are as follows: 17μm / 56μm / 12μm / 36μm / 53μm / 38μm, wherein the heat sealing layer PP is blended and dispersed with 8% by mass of nano titanium dioxide.

[0057] Embodiment 15 KNY / Example 10 / high temperature cooking grade adhesive layer / NY / Example 3 / PE, thicknesses are as follows: 15μm / 58μm / 20μm / 32μm / 52μm / 28μm, wherein the heat sealing layer PE is blended and dispersed with 5% by mass 2-benzotriazole.

[0058] Example 16 KNY / Example 8 / semi-high temperature cooking grade adhesive layer / PET / Example 4 / PE, thicknesses are: 25μm / 62μm / 14μm / 32μm / 49μm / 35μm, wherein the heat sealing layer PE is blended and dispersed with 8% by mass of 2-benzotriazole.

[0059] Embodiment 17 PET-AlO x / Example 9 / water-boiled grade adhesive layer / BOPE / Example 3 / PP, the thicknesses are as follows: 26μm / 54μm / 7μm / 32μm / 54μm / 32μm, wherein the heat sealing layer PP is blended and dispersed with 12% mass fraction of nano zinc oxide.

[0060] Embodiment 18 PET-AlO x / Example 7 / high temperature cooking grade adhesive layer / MDOPE / Example 4 / PP, the thicknesses are as follows: 25μm / 58μm / 14μm / 32μm / 38μm / 38μm, wherein the heat sealing layer PP is blended and dispersed with 12% by mass of carotenoids.

[0061] Embodiment 19 PET-AlO x / Example 8 / semi-high temperature cooking grade adhesive layer / NY / Example 5 / PE, thicknesses are: 22μm / 53μm / 17μm / 39μm / 42μm / 29μm, wherein the heat sealing layer PE is blended and dispersed with 15% mass fraction of nano zinc oxide.

[0062] Embodiment 20 BOPP-AlO x / Example 10 / water-boiled grade adhesive layer / PET / Example 5 / PE, thicknesses are: 25μm / 32μm / 12μm / 33μm / 41μm / 41μm, wherein the heat sealing layer PE is blended and dispersed with 12% mass fraction of vitamin B.

[0063] Embodiment 21 BOPP-AlO x / Example 6 / high temperature cooking grade adhesive layer / BOPE / Example 2 / PE, thicknesses are: 24μm / 30μm / 21μm / 33μm / 29μm / 32μm, wherein the heat sealing layer PE is blended and dispersed with 10% by mass of sodium phosphite.

[0064] Embodiment 22 BOPP-AlO x / Example 9 / semi-high temperature cooking grade adhesive layer / NY / Example 3 / PP, thicknesses are: 25μm / 56μm / 16μm / 33μm / 39μm / 39μm, wherein the heat sealing layer PP is blended and dispersed with 10% by mass of hindered phenol.

[0065] Embodiment 23 PET-SiO2 / Example 10 / water-boiled grade adhesive layer / MDOPE / Example 1 / PP, thicknesses are as follows: 23μm / 38μm / 16μm / 37μm / 42μm / 35μm, wherein the heat sealing layer PP is blended and dispersed with 10% by mass of hindered phenol.

[0066] Embodiment 24 PET-SiO2 / Example 9 / water-boiled grade adhesive layer / NY / Example 2 / PE, thicknesses are: 17μm / 32μm / 25μm / 30μm / 34μm / 33μm, wherein the heat sealing layer PE is blended and dispersed with 8% by mass of nano zinc oxide.

[0067] Embodiment 25 PET-SiO2 / Example 8 / high temperature cooking grade adhesive layer / MDOPE / Example 5 / PE, thicknesses are as follows: 16μm / 32μm / 12μm / 41μm / 57μm / 33μm, wherein the heat sealing layer PE is blended and dispersed with 8% by mass of nano titanium dioxide.

[0068] At 25°C and standard atmospheric pressure, the composite film materials of Examples 11 to 25 were tested for oxygen permeability and water vapor permeability in accordance with GB / T19789-2021 "Oxygen Permeability Test for Plastic Films and Sheets for Packaging Materials by Coulometer Detection Method" and GB / T1037-2021 "Determination of Water Vapor Permeability of Plastic Films and Sheets by Cup Weight Gain and Weight Loss Method", and the haze test was carried out in a dark room using a haze detector. After each example was exposed to 1500 lumens of light for 2 hours, a reflectivity tester was used to avoid measuring the reflectivity of the ink layer / reflective layer. The test results are shown in Table 1, where the unit of OTR in the table is cm 3 / (m 2×24h×0.1MPa), WTR unit is g / m 2 ×24h.

[0069] Table 1 Example OTR WTR Haze Reflectivity of reflective layer Embodiment 11 9 5 5% 32% Example 12 2 1.8 6% 35% Embodiment 13 0.4 0.3 4% 28% Embodiment 14 1.4 1.3 5% 31% Embodiment 15 0.5 0.4 7% 27% Example 16 1.3 1.2 5% 25% Embodiment 17 10 4 5% 24% Embodiment 18 0.3 0.5 4% 32% Embodiment 19 1.5 1.2 6% 31% Embodiment 20 8 4 7% 35% Embodiment 21 0.3 0.3 5% 37% Embodiment 22 1.7 2 4% 33% Embodiment 23 7 3 8% 28% Embodiment 24 10 3 5% 29% Embodiment 25 0.4 0.3 6% 29% Visually inspect the printing quality, and check whether there are obvious (visible to the naked eye) defects. Observe whether there are obvious printing defects, and the results are all qualified.

[0070] GB / T19394-2003 was used to conduct UV wavelength absorption tests on the embodiments in Table 1. The results showed that all of them completely blocked 300-400nm ultraviolet rays. The test results are shown in Table 2. The values ​​shown in Table 2 are percentages.

[0071] Table 2 Example 300nm 310nm 320nm 330nm 340nm 350nm 360nm 370nm 380nm 390nm 400nm 11 0.441 7.270 50.845 56.202 59.329 60.275 61.278 61.701 52.658 49.45 45.687 12 0.852 7.558 51.211 56.74 59.762 61.221 62.244 62.525 53.55 50.275 46.449 13 0.926 6.974 48.564 53.927 56.984 63.17 64.209 64.554 55.233 51.889 47.941 14 1.196 7.129 47.786 53.025 55.984 63.418 64.484 64.872 55.871 52.423 48.434 15 0.996 7.254 49.346 54.778 57.743 64.674 65.631 65.96 56.698 53.217 49.168 16 1.114 7.541 51.309 56.912 59.837 61.98 62.923 63.213 54.224 51.032 47.149 17 0.706 7.164 51.896 57.44 60.481 62.458 63.272 63.663 54.644 51.413 47.501 18 0.753 7.222 51.685 57.154 60.315 62.211 63.211 63.593 54.715 51.341 47.434 19 1.299 7.660 52.2 57.663 60.709 60.599 61.788 62.247 53.505 50.247 46.424 20 0.718 6.972 48.922 54.358 57.378 57.237 58.026 58.345 49.876 46.703 43.149 21 0.677 7.317 51.107 56.611 59.583 58.532 59.571 59.964 51.245 47.999 44.347 22 0.892 7.223 50.622 56.105 58.993 60.75 61.703 61.945 53.099 49.834 46.042 23 0.854 7.148 50.044 55.494 58.512 57.798 58.438 58.9 50.244 47.238 43.644 24 0.862 7.314 50.784 56.201 59.157 60.278 61.265 61.489 52.772 49.386 45.628 25 0.333 7.085 48.782 54.214 57.195 57.057 57.693 57.816 49.341 46.15 42.638 Sequentially, the high-temperature cooking grade adhesive layer / semi-high-temperature cooking grade adhesive layer / water boiling grade adhesive layer can achieve the barrier effects of OTR≤0.5, WTR≤0.5; OTR≤2, WTR≤2; OTR≤10, WTR≤5 respectively. Anti-ultraviolet, Examples 1 to 15 can all achieve full blocking of ultraviolet light with a wavelength below 400nm. The modified barrier layer can also help improve oil resistance, acid and alkali resistance, radiation resistance and wear resistance. When the reflective layer is affected by light, it can reflect specific light corresponding to the color change of the reflective layer, reducing the adverse effects of different light on the contents, especially food. When the ink layer and the reflective layer change color in different types, the ink printed text or pattern can be made more eye-catching.

[0072] The same haze reflectance test was performed on Examples 1 to 10, and the results are shown in Table 3. Similarly, a 300-400 nm ultraviolet wavelength absorption test was performed on them, and the results are shown in Table 4. The values ​​shown in Table 4 are percentages.

[0073] Table 3 Example Haze Reflectivity of reflective layer Example 1 2% 46% Example 2 3% 49% Example 3 2% 40% Example 4 4% 39% Example 5 3% 38% Example 6 2% 35% Example 7 2% 32% Example 8 3% 34% Example 9 2% 32% Example 10 2% 32% Table 4 Example 300nm 310nm 320nm 330nm 340nm 350nm 360nm 370nm 380nm 390nm 400nm 1 37.125 42.379 52.732 67.975 72.359 76.258 78.547 80.281 78.741 76.167 72.391 2 36.271 42.371 52.67 67.852 72.201 76.182 78.471 80.162 78.625 76.548 72.346 3 39.584 41.986 55.981 68.58 73.77 77.201 78.61 80.957 78.841 76.329 73.16 4 37.465 41.628 54.32 68.233 73.42 77.355 78.103 80.624 78.927 76.548 72.177 5 38.168 43.718 52.776 67.741 72.107 75.67 77.544 79.344 77.671 76.159 72.961 6 37.751 42.887 51.982 66.866 71.355 75.934 77.023 79.822 78.023 76.980 74.645 7 36.011 41.655 52.021 67.021 71.725 75.743 78.211 81.213 79.004 77.295 73.154 8 37.106 43.571 53.287 67.124 71.985 75.312 78.625 81.106 80.102 77.641 73.264 9 38.207 42.011 53.61 67.875 72.54 73.677 79.867 79.864 80.234 77.422 73.462 10 38.657 41.997 53.2 67.203 72.101 73.724 79.504 79.743 79.257 77.027 73.024 It is worth noting that the color-changing transparency referred to in the present invention refers to a color structure similar to, for example, a copper sulfate solution, which has the property of being transparent (meaning that at least light other than the color corresponding to the reflective layer can penetrate).

[0074] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An anti-ultraviolet high-barrier transparent film, characterized in that: From outside to inside, the settings include: The barrier layer includes a K modified film, AlO x Modified membrane, SiO2 modified membrane; Adhesive layer, the adhesive layer is made by coating and compounding a transparent and boiling-resistant adhesive; An intermediate layer, wherein the intermediate layer is a functional film layer; A reflective layer, wherein the reflective layer is a diarylethene film A; A heat-sealing layer, wherein the heat-sealing layer is a PP or PE film with UV-resistant particles uniformly dispersed therein; The bottom of the barrier layer is glued to the middle layer through an adhesive layer, and the middle layer, the reflective layer and the heat sealing layer are heat-pressed and bonded.

2. The UV-resistant high-barrier transparent film according to claim 1, characterized in that: The middle layer includes at least one of NY, PET, BOPE and MDOPE.

3. The anti-ultraviolet high-barrier transparent film according to claim 1, characterized in that: The thickness ratio of the barrier layer / adhesive layer / intermediate layer / reflective layer / heat-sealing layer is: 0.75~1.25 / 0.5~1 / 1.5~2 / 1.5~3 / 1.5~2。 4. The anti-ultraviolet high-barrier transparent film according to claim 1, characterized in that: The adhesive layer is one of water-boiling grade glue, semi-high temperature cooking grade glue and high temperature cooking grade glue.

5. The UV-resistant high-barrier transparent film according to claim 1, characterized in that: An ink layer is further arranged between the barrier layer and the adhesive layer. The barrier layer at least partially covers the ink layer. The ink layer is glued to one side of the barrier layer through the adhesive layer.

6. The anti-ultraviolet high-barrier transparent film according to claim 5, characterized in that: The ink layer is a diarylethene film B, and the diarylethene film A and the diarylethene film B have different reflective colors.

7. The anti-ultraviolet high-barrier transparent film according to claim 1, characterized in that: The preparation method of the diarylethene film comprises the following steps: S1, weigh 5-20 parts of a diarylethene photochromic compound, 150-200 parts of an ethyl acetate-water solution, and 1-5 parts of a surfactant and mix them evenly; S2, heating the mixture obtained in S1 to 40-60 degrees Celsius and keeping the temperature for 1-2 hours to prepare an active intermediate; S3, coating the active intermediate obtained in S2 onto the surface of at least one of the adjacent layers, and drying at 60-80 degrees Celsius.

8. The UV-resistant high-barrier transparent film according to claim 7, characterized in that: The diarylethene photochromic compound comprises: 2,3-Bis(2,4,5-trimethyl-3-thienyl)maleic anhydride, 2,3-Bis(2,4,5-trimethyl-3-thienyl)maleimide, At least one of cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethylene.

9. The UV-resistant high-barrier transparent film according to claim 7, characterized in that: In S3, the surface of at least one of the adjacent layers of the diarylethene film is pretreated, and the pretreatment includes: activating the two layers of the film by keeping them at 40-50° C. for more than 1 hour.

10. The UV-resistant high-barrier transparent film according to claim 7 or 9, characterized in that: The light transmittance of the diarylethene film is greater than 95%, and the haze is less than 5%.

Images