An ultraviolet resistant high-barrier transparent film and a preparation method thereof

Abstract

The application discloses a kind of multilayer structure's anti-ultraviolet high-barrier transparent film and preparation method thereof, composite film material includes barrier layer, adhesive layer, intermediate layer and heat-sealing layer. Among them, barrier layer selects KPET, KNY and other high-efficiency barrier materials, and heat-sealing layer is dispersed with anti-ultraviolet particles, and the ultraviolet protection capacity is improved. Intermediate layer uses NY, PET and other reinforced film structures, and the adhesive layer ensures the stable connection between layers. In addition, the introduction of ink layer and reflection layer can use two kinds of diarylethene film with different color change, with photochromic characteristics, not only add beauty, but also improve product interaction, reflect ultraviolet after color change, improve the anti-ultraviolet high-barrier of the application, while maintaining its transparent effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite film, in particular to an anti-ultraviolet high-barrier transparent film for food packaging. BACKGROUND

[0002] PrePack is a kind of aseptic packaging, which is often 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-extrusion films and aluminum plastic composite films. Such composite films can effectively block the influence of external factors such as oxygen and moisture on food quality, thereby prolonging the shelf life of food. In order for consumers to directly observe the state of the food in the package, there is a demand for transparent food packaging. However, the transparent packaging bag cannot block ultraviolet rays, and ultraviolet radiation can easily cause the degradation of light-sensitive ingredients such as vitamins in food, oxidation of fatty substances, and other changes, affecting the flavor and taste of food. Therefore, it is necessary to design and manufacture an anti-ultraviolet high-barrier transparent film. In the prior art, PET is used as a transparent substrate, and anti-ultraviolet additives are added to achieve anti-ultraviolet function. However, this kind of technical scheme has limited blocking effect on ultraviolet light, and can only ensure better blocking effect in the range of 200~360nm, and the blocking performance of water and oxygen is poor, OTR≤120, WTR≤15. SUMMARY

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

[0004] To achieve the above-mentioned purposes, the technical solutions provided by the present application are as follows:

[0005] An anti-ultraviolet high-barrier transparent film is provided, which is sequentially arranged from the outside to the inside and includes:

[0006] a barrier layer, the barrier layer includes a K-modified film, an AlO x modified film, SiO2 modified film;

[0007] an adhesive layer, the adhesive layer is a transparent and steam-resistant adhesive coating composite;

[0008] an intermediate layer, the intermediate layer is a functional film layer;

[0009] a reflective layer, the reflective layer is a diarylethene film (A);

[0010] a heat-sealing layer, the heat-sealing layer is a PP or PE film uniformly dispersed with anti-ultraviolet particles,

[0011] The bottom of the barrier layer is glued to the intermediate layer through the adhesive layer, and the intermediate layer, the reflective layer and the heat-seal layer are heat-sealed and attached.

[0012] Further, the barrier layer comprises at least one of KPET, KNY, PET-AlO x , BOPP-AlO x , PET-SiO2

[0013] Further, the intermediate layer comprises at least one of NY, PET, BOPE, MDOPE.

[0014] Further, the thickness ratio of the barrier layer / adhesive layer / intermediate layer / reflective layer / heat-seal layer is (0.75~1.25) / (0.5~1) / (1.5~2) / (1.5~3) / (1.5~2).

[0015] Further, the adhesive layer is one of water-cooked glue, semi-high-temperature cooked glue, and high-temperature cooked glue.

[0016] Further, an ink layer is further arranged 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.

[0017] Further, the ink layer is a diarylethene film (B), and the diarylethene film (A) and the diarylethene film (B) are any two of red light color-changing diarylethene film, blue light color-changing diarylethene film, and purple light color-changing diarylethene film.

[0018] A preparation method of a diarylethene film, comprising the following steps:

[0019] S1, according to weight parts, take 5~20 parts of diarylethene photochromic compound, 150~200 parts of ethyl acetate-water solution with a volume fraction of 75~85%, and 1~5 parts of surfactant, and stir and mix uniformly;

[0020] S2, heat the mixture obtained in S1 to 40~60 degrees Celsius, and keep warm for 1~2 hours to prepare an active intermediate;

[0021] S3, coat the active intermediate obtained in S2 to the surface of at least one of the adjacent layers, and dry at 60~80 degrees Celsius.

[0022] Further, the diarylethene photochromic compound comprises:

[0023] 2,3-bis(2,4,5-trimethyl-3-thienyl) maleic anhydride,

[0024] 2,3-bis(2,4,5-trimethyl-3-thienyl) maleic anhydride,

[0025] at least one of cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethene.

[0026] Further, in S3, the surface of the intermediate layer and / or the heat-sealing layer is pretreated, and the pretreatment comprises: incubating the intermediate layer and / or the heat-sealing layer at 40-50 DEG C.

[0027] Further, the light transmittance of the diarylethene film is greater than 95%, and the haze is less than 5%.

[0028] The advantages and beneficial effects of the present application are that:

[0029] 1. High barrier and anti-ultraviolet: By selecting a specific barrier layer, efficient barrier to external environmental factors is achieved, including oxygen, moisture, etc. At the same time, the uniformly dispersed anti-ultraviolet particles in the heat-sealing layer can effectively resist the invasion of ultraviolet light, protecting the packaging contents from damage caused by ultraviolet light.

[0030] 2. Structure and function composite: The adhesion layer tightly bonds each functional layer, not only ensuring the overall stability of the film structure, but also achieving effective superposition of the functions of each layer. The selection of the intermediate layer enhances the mechanical properties and durability of the film.

[0031] 3. Weather resistance and aesthetics: The setting of the ink layer not only provides rich visual effects 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.

[0032] 4. Intelligent color-changing function: The transparent diarylethene film (A) and diarylethene film (B) used in the reflective layer and ink layer have light-sensitive color-changing properties, which can exhibit different colors under ultraviolet light. When the reflective layer turns blue or purple under ultraviolet light, the surface reflects blue-violet light, further improving the anti-ultraviolet technology effect, while the ink layer turns red, without affecting the visual effect of the ink layer. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a structural schematic diagram of the present application;

[0034] In the figure:

[0035] 1-barrier layer, 2-ink layer, 3-adhesion layer, 4-intermediate layer, 5-reflective layer, 6-heat-sealing layer. DETAILED DESCRIPTION

[0036] OTR is the oxygen transmission rate (Oxygen transmission rate), which refers to the transmission rate of oxygen through a material or packaging, commonly used to measure the oxygen barrier performance of materials or packaging.

[0037] WTR is the water vapor transmission rate, which refers to the transmission rate of water vapor of the material or package.

[0038] PE: polyethylene film.

[0039] PP: polypropylene film.

[0040] BOPE: biaxially oriented polyethylene film.

[0041] MDOPE: machine direction oriented polyethylene film.

[0042] KPET: PET (polyethylene terephthalate) as the base material, the prefix K indicates that the plastic film is coated with high-barrier PVDC (polyvinylidene chloride) on one side.

[0043] KNY: NY (polyamide, nylon) as the base material, the prefix K indicates that the plastic film is coated with high-barrier PVDC (polyvinylidene chloride) on one side.

[0044] PET-AlOx: PET as the base material, vacuum evaporation of aluminum oxide on the PET corona treatment side, the other side is a non-corona treatment plastic film.

[0045] PET-SiO2: composite film made of PET as the base material and nano-silicon dioxide added during the PET melt preparation process.

[0046] BOPP-AlO x : BOPP (biaxially oriented polypropylene film) as the base material, vacuum evaporation of aluminum oxide on the BOPP corona treatment side, the other side is a non-corona treatment plastic film,

[0047] In the corresponding embodiments of the present application, the side of the K modified film coated with PVDC is the side away from the adhesive layer.

[0048] In the corresponding embodiments of the present application, the AlO x The corona treatment side of the modified film is complexed with the adhesive layer.

[0049] GB / T 10004 provides that the package is divided into four grades according to the use temperature, namely ordinary grade (≤80℃), boiling grade (80℃ above ~100℃), semi-high temperature cooking grade (100℃ above ~121℃), and high temperature cooking grade (121℃ above ~145℃).

[0050] Diaryl ethylene is a class of photochromic materials that undergo color changes under specific light conditions. Generally, diaryl ethylene will change from colorless or light color to dark color, such as blue, purple or red, after being irradiated by ultraviolet light. This color change is usually reversible, that is, the material can return to the original colorless or light color state under another light condition or heat.

[0051] Barrier layer: the barrier layer can be composed of K modified film, AlO x Modified film, SiO2 modified film, these materials have high barrier properties, can effectively block oxygen, water vapor and ultraviolet light, protect the inner layer material from the influence of the external environment.

[0052] Adhesive layer: the adhesive layer uses transparent and steam-resistant adhesive to ensure the firm adhesion between the barrier layer and the intermediate layer. This adhesive not only can withstand the high temperature and high pressure in the steaming process, but also maintains the transparency of the film, without affecting the overall visual effect.

[0053] 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 increasing specific optical effects. The key is that the intermediate layer avoids the direct contact between the adhesive layer and the reflective layer, and 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 reflection function. It should be understood that the ink layer can optionally add reflection effect, and can also be printed by conventional technology to obtain the effect of the prior art, without the need for intelligent color change. The heat-sealing and bonding between the intermediate layer and the barrier layer, reflective layer and heat-sealing layer ensure the close connection between the layers, improving the overall performance of the film.

[0054] The reflective layer is obtained by coating and drying an ethyl acetate solution of diarylethene. Notably, a certain volume fraction of ethyl acetate-water solution is used to disperse the diarylethene. On the one hand, ethyl acetate is easy to evaporate, which facilitates subsequent coating and drying. On the other hand, ethyl acetate, as a less polar solvent, is compounded with deionized water as a solvent, so that the diarylethene is enriched at the interface of ethyl acetate-water, which is more conducive to the stirring and dispersion of the diarylethene with a large molecular structure. Moreover, the reflective layer has the ability to reflect specific wavelengths of light while reducing the haze that may occur under non-light conditions, thereby achieving specific color effects while maintaining transparency. The heat-sealable bonding between the reflective layer and the intermediate layer and the heat-sealable layer ensures the stability and durability of the reflective layer. The present application also provides a preparation method for a diarylethene film. The diarylethene is dispersed by an ethyl acetate solution and a surfactant, then heat-treated and activated to form a stable active intermediate. 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-sealable layer, and dried at 60-80°C. The coating process ensures uniform distribution of the active intermediate, and the drying process helps to form a stable film structure. The use of an ethyl acetate solution with a surfactant can achieve uniform dispersion of the diarylethene and facilitate subsequent drying and removal. The most prominent function of the reflective layer structure is to fully utilize the reflective properties of the optical film to block a portion of ultraviolet light and a certain range of visible light, thereby reducing the problem of ultraviolet light penetrating the subsequent film layer to irradiate the food, prolonging the packaging life, and further, the brighter color exhibited by photoluminescence can directly remind the salesperson or customer that the food is being irradiated by ultraviolet light, so as to shield it.

[0055] The heat-sealable layer is a PP or PE film uniformly dispersed with anti-ultraviolet particles, which not only provides good heat-sealable performance, but also enhances the anti-ultraviolet ability of the film. The addition of anti-ultraviolet particles can be used as the last barrier to absorb or reflect ultraviolet light, protecting the internal structure of the film from ultraviolet damage.

[0056] The ink layer is a diarylethene film (B) that forms a red, blue, or purple color-changing effect with the diarylethene film (A) of the reflective layer, increasing the visual appeal and functionality of the film. The ink layer is glued to one side of the barrier layer through the adhesive layer, ensuring the stability of the ink layer and the durability of the color. The synergistic effect of the materials in each layer ensures excellent performance in barrier properties, transparency, boiling resistance, heat-sealable performance, and anti-ultraviolet function of the anti-ultraviolet high-barrier transparent film, which is suitable for various application scenarios that require high barrier and anti-ultraviolet protection.

[0057] The structural design of the above-mentioned anti-UV high-barrier transparent film not only embodies 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 is crucial to maintaining the high transparency of the film. Appropriate thickness can reduce multiple reflections and scattering of light within the material, thereby improving transparency. Specifically, a barrier layer that is too thick will increase light scattering and absorption, reducing transparency; a barrier layer that is too thin may reduce barrier performance. The thickness of the adhesive layer needs to be thin enough to reduce light reflection at the interface between the layers, avoiding the formation of multiple reflections and interference of light, thereby maintaining the high transparency of the film. At the same time, the adhesive layer needs to have sufficient strength to ensure firm adhesion between the layers. The thickness of the intermediate layer needs to balance functionality and transparency. A too thick intermediate layer may introduce additional light scattering, affecting transparency; a too thin intermediate layer may not be able to provide sufficient functional performance. The reflective layer must be of appropriate thickness to achieve the desired smart reflection effect, while also negatively affecting transparency. Similarly, the anti-UV particles in the heat-seal layer will increase light scattering and thus reduce transparency. The thickness ratio of each layer of material is based on optical principles, aiming to balance barrier properties, functionality, and transparency. By controlling the overall thickness of each layer, optimal performance is ultimately achieved.

[0058] The specific embodiments of the present application are further described below in conjunction with the accompanying drawings and examples. The following examples are only used to more clearly illustrate the technical solutions of the present application, and cannot be used to limit the protection scope of the present application.

[0059] Examples 1-5 are a composite preparation method of a diarylethene film (A), wherein a certain volume fraction of ethyl acetate, and the balance includes acetic acid, ethanol, and water formed by esterification of acetic acid-ethanol.

[0060] Example 1

[0061] A method for preparing a diarylethene film, comprising the following steps:

[0062] S1, 2, 3-bis(2, 4, 5-trimethyl-3-thienyl) maleic anhydride is weighed by weight parts

[0063] 5 parts, 75% by volume of ethyl acetate 200 parts, 1 part of surfactant is stirred and mixed uniformly;

[0064] S2, the mixture obtained in S1 is heated to 45 degrees Celsius and kept for 1 hour to prepare an active intermediate;

[0065] S3, the active intermediate obtained in S2 is coated onto the surface of the intermediate layer and dried at 80 degrees Celsius; an intermediate layer / reflective layer structure film is prepared.

[0066] Example 2

[0067] A method for preparing a diarylethene film, comprising the following steps:

[0068] S1, 2,3-bis(2,4,5-trimethyl-3-thienyl)maleimide was weighed in parts by weight,

[0069] 10 parts, 75% by volume ethyl acetate 180 parts, 3 parts of surfactant were stirred and uniformly mixed;

[0070] S2, the mixture obtained in S1 was heated to 60 degrees Celsius, and incubated for 2 hours to prepare an active intermediate;

[0071] S3, after the intermediate layer and the heat-sealing layer were incubated and activated at 50°C for 1h, the active intermediate obtained in S2 was coated onto the surface of the intermediate layer and the heat-sealing layer, and dried at 60 degrees Celsius; an intermediate layer / reflection layer / heat-sealing layer structure film was prepared.

[0072] Example 3

[0073] A preparation method of a diarylethene film, comprising the following steps:

[0074] S1, cis-1,2-dicyano-1,2-bis(2,4,5-trimethyl-3-thienyl)ethylene 20 parts by weight, 85% by volume ethyl acetate 150-200 parts, 5 parts of surfactant were stirred and uniformly mixed;

[0075] S2, the mixture obtained in S1 was heated to 40 degrees Celsius, and incubated for 2 hours to prepare an active intermediate;

[0076] S3, after the intermediate layer and the heat-sealing layer were incubated and activated at 60°C for 1h, the active intermediate obtained in S2 was coated onto the surface of the heat-sealing layer, and dried at 75 degrees Celsius; an intermediate layer / reflection layer / heat-sealing layer structure film was prepared.

[0077] Example 4

[0078] A preparation method of a diarylethene film, comprising the following steps:

[0079] S1, 2,3-bis(2,4,5-trimethyl-3-thienyl)maleic anhydride 10 parts, 2,3-bis(2,4,5-trimethyl-3-thienyl)maleimide 10 parts, 75% by volume ethyl acetate 150-200 parts, 1-5 parts of surfactant were stirred and uniformly mixed;

[0080] S2, the mixture obtained in S1 was heated to 60 degrees Celsius, and incubated for 1 hour to prepare an active intermediate;

[0081] S3, after the intermediate layer and the heat-sealing layer were incubated and activated at 50°C for 2h, the active intermediate obtained in S2 was coated onto the surface of the intermediate layer and the heat-sealing layer, and dried at 80 degrees Celsius; an intermediate layer / reflection layer / heat-sealing layer structure film was prepared.

[0082] Example 5

[0083] A preparation method of a diarylethene film, comprising the following steps:

[0084] S1, 2, 3-bis (2, 4, 5-trimethyl-3-thienyl) maleimide 5 parts, cis-1, 2-dicyano-1, 2-bis (2, 4, 5-trimethyl-3-thienyl) ethylene 10 parts, 75% by volume ethyl acetate 150~200 parts, surfactant 1~5 parts are weighed by weight parts and stirred uniformly;

[0085] S2, the mixture obtained in S1 is heated to 60 degrees Celsius and kept for 1.5 hours to prepare an active intermediate;

[0086] S3, after the intermediate layer and the heat-sealing layer are activated at 45 degrees Celsius 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 degrees Celsius; an intermediate layer / reflection layer / heat-sealing layer structure film is prepared.

[0087] Examples 6~10 are a composite preparation method of a diarylethene film (A),

[0088] Example 6

[0089] The difference from example 1 is only that 20 parts of ink are also mixed in S1, and S3 is that the active intermediate obtained in S2 is coated on the surface of the barrier layer and dried at 80 degrees Celsius; a barrier layer / ink layer structure film is prepared.

[0090] Example 7

[0091] The difference from example 2 is only that 25 parts of ink are also mixed in S1, and S3 is that, after the barrier layer is activated at 50 degrees Celsius for 1 hour, the active intermediate obtained in S2 is coated on the surface of the barrier layer and dried at 60 degrees Celsius; a barrier layer / ink layer structure film is prepared.

[0092] Example 8

[0093] The difference from example 3 is only that 30 parts of ink are also mixed in S1, and S3 is that, after the barrier layer is activated at 60 degrees Celsius for 1 hour, the active intermediate obtained in S2 is coated on the surface of the barrier layer and dried at 75 degrees Celsius; a barrier layer / ink layer structure film is prepared.

[0094] Example 9

[0095] The difference from example 4 is only that 25 parts of ink are also mixed in S1, and S3 is that, after the barrier layer is activated at 50 degrees Celsius for 2 hours, the active intermediate obtained in S2 is coated on the surface of the barrier layer and dried at 80 degrees Celsius; a barrier layer / ink layer structure film is prepared.

[0096] Example 10

[0097] The difference from Example 5 is that 25 parts of ink is also mixed in S1, and S3 is that after the barrier layer is activated at 45℃ for 2h, the active intermediate obtained in S2 is coated onto the surface of the barrier layer and dried at 75℃; a barrier layer / ink layer structure film is prepared.

[0098] Examples 11-25 are structures of anti-ultraviolet high-barrier transparent films: the PP or PE in the heat-sealing layer of each example contains anti-ultraviolet particles, which are preferably one or a combination of hydroxybenzophenone, hydroxyphenyl-S-triazine, 2-benzotriazole, titanium dioxide, zinc oxide, polyphenol, vitamin, carotenoid, hindered phenol, and phosphite. The anti-ultraviolet particles are extruded and blown into a film by blending with PP / PE, and then coated with a reflective layer and / or an intermediate layer, and then hot-pressed at 50-70℃ and 0.4-1MPa. The ink layer is directly coated onto the surface of the barrier layer, dried at 60℃ for 2h or more to shape, and then glued to the intermediate layer through an adhesive layer.

[0099] Example 11

[0100] KPET / Example 6 / boiling grade adhesive layer / PET / Example 1 / PP, with thicknesses being 21μm / 45μm / 20μm / 34μm / 62μm / 38μm, respectively, and the heat-sealing layer PP is blended and dispersed with 10% by mass of hydroxybenzophenone.

[0101] KPET / Example 6 / boiling grade adhesive layer / PET / Example 1 / PP, with thicknesses being 21μm / 45μm / 20μm / 34μm / 62μm / 38μm, respectively, and the heat-sealing layer PP is blended and dispersed with 10% by mass of hydroxybenzophenone.

[0102] Example 12

[0103] KPET / Example 7 / semi-high-temperature boiling grade adhesive layer / PET / Example 2 / PP, with thicknesses being 22μm / 52μm / 10μm / 42μm / 42μm / 37μm, respectively, and the heat-sealing layer PP is blended and dispersed with 5% by mass of hydroxyphenyl-S-triazine.

[0104] KPET / Example 7 / semi-high-temperature boiling grade adhesive layer / PET / Example 2 / PP, with thicknesses being 22μm / 52μm / 10μm / 42μm / 42μm / 37μm, respectively, and the heat-sealing layer PP is blended and dispersed with 5% by mass of hydroxyphenyl-S-triazine.

[0105] Example 13

[0106] KPET / Example 10 / high-temperature boiling grade adhesive layer / BOPE / Example 4 / PE, with thicknesses being 20μm / 37μm / 15μm / 33μm / 45μm / 38μm, respectively, and the heat-sealing layer PE is blended and dispersed with 5% by mass of 2-benzotriazole.

[0107] KPET / Example 10 / high-temperature boiling grade adhesive layer / BOPE / Example 4 / PE, with thicknesses being 20μm / 37μm / 15μm / 33μm / 45μm / 38μm, respectively, and the heat-sealing layer PE is blended and dispersed with 5% by mass of 2-benzotriazole.

[0108] Example 14

[0109] KNY / Example 6 / semi-high temperature cooking grade adhesive layer / MDOPE / Example 2 / PP, thicknesses in turn are:

[0110] 17 μιη / 56 μιη / 12 μιη / 36 μιη / 53 μιη / 38 μιη, wherein the heat-sealing layer PP is blended and dispersed with 8% mass fraction of nano-titanium dioxide.

[0111] Example 15

[0112] KNY / Example 10 / high temperature cooking grade adhesive layer / NY / Example 3 / PE, thicknesses in turn are:

[0113] 15 μιη / 58 μιη / 20 μιη / 32 μιη / 52 μιη / 28 μιη, wherein the heat-sealing layer PE is blended and dispersed with 5% mass fraction of 2-benzotriazole.

[0114] Example 16

[0115] KNY / Example 8 / semi-high temperature cooking grade adhesive layer / PET / Example 4 / PE, thicknesses in turn are:

[0116] 25 μιη / 62 μιη / 14 μιη / 32 μιη / 49 μιη / 35 μιη, wherein the heat-sealing layer PE is blended and dispersed with 8% mass fraction of 2-benzotriazole.

[0117] Example 17

[0118] PET-A10 x / Example 9 / water cooking grade adhesive layer / BOPE / Example 3 / PP, thicknesses in turn are:

[0119] 26 μιη / 54 μιη / 7 μιη / 32 μιη / 54 μιη / 32 μιη, wherein the heat-sealing layer PP is blended and dispersed with 12% mass fraction of nano-zinc oxide.

[0120] Example 18

[0121] PET-A10 x / Example 7 / high temperature cooking grade adhesive layer / MDOPE / Example 4 / PP, thicknesses in turn are:

[0122] 25 μιη / 58 μιη / 14 μιη / 32 μιη / 38 μιη / 38 μιη, wherein the heat-sealing layer PP is blended and dispersed with 12% mass fraction of carotenoid.

[0123] Example 19

[0124] PET-A10 x / Example 8 / semi-high temperature cooking grade adhesive layer / NY / Example 5 / PE, thicknesses in turn are:

[0125] 22μm / 53μm / 17μm / 39μm / 42μm / 29μm, wherein the heat-sealing layer PE is blended with 15% mass fraction of nano zinc oxide dispersed therein.

[0126] Example 20

[0127] BOPP-A10 x / Example 10 / boiling grade adhesive layer / PET / Example 5 / PE, with thicknesses in turn being:

[0128] 25μm / 32μm / 12μm / 33μm / 41μm / 41μm, wherein the heat-sealing layer PE is blended with 12% mass fraction of vitamin B dispersed therein.

[0129] Example 21

[0130] BOPP-A10 x / Example 6 / high-temperature boiling grade adhesive layer / BOPE / Example 2 / PE, with thicknesses in turn being:

[0131] 24μm / 30μm / 21μm / 33μm / 29μm / 32μm, wherein the heat-sealing layer PE is blended with 10% mass fraction of sodium phosphite dispersed therein.

[0132] Example 22

[0133] BOPP-A10 x / Example 9 / semi-high-temperature boiling grade adhesive layer / NY / Example 3 / PP, with thicknesses in turn being:

[0134] 25μm / 56μm / 16μm / 33μm / 39μm / 39μm, wherein the heat-sealing layer PP is blended with 10% mass fraction of hindered phenol dispersed therein.

[0135] Example 23

[0136] PET-SiO2 / Example 10 / boiling grade adhesive layer / MDOPE / Example 1 / PP, with thicknesses in turn being:

[0137] 23μm / 38μm / 16μm / 37μm / 42μm / 35μm, wherein the heat-sealing layer PP is blended with 10% mass fraction of hindered phenol dispersed therein.

[0138] Example 24

[0139] PET-SiO2 / Example 9 / boiling grade adhesive layer / NY / Example 2 / PE, with thicknesses in turn being:

[0140] 17μm / 32μm / 25μm / 30μm / 34μm / 33μm, wherein the heat-sealing layer PE is blended with 8% mass fraction of nano zinc oxide dispersed therein.

[0141] Example 25

[0142] PET-SiO2 / Example 8 / High-Temperature Retort Grade Adhesive Layer / MDOPE / Example 5 / PE, thicknesses are as follows:

[0143] The thicknesses are 16μm / 32μm / 12μm / 41μm / 57μm / 33μm, with the heat-sealing layer PE being blended and dispersed with 8% by mass of nano-titanium dioxide.

[0144] Under standard atmospheric pressure and at 25°C, the composite film materials of Examples 11-25 were tested for oxygen permeability and water vapor permeability according to GB / T19789-2021 "Test of Oxygen Permeability of Plastic Films and Sheets for Packaging Materials - Coulometric Method" and GB / T1037-2021 "Determination of Water Vapor Permeability of Plastic Films and Sheets - Cup Method for Weight Gain and Loss". A haze meter was used for haze testing in a dark room. After each example was irradiated with 1500 lumens of light for 2 hours, a reflectance meter was used to measure the reflectance of the ink / reflective layer, avoiding the ink layer. The test results are shown in Table 1, where OTR is expressed in cm. 3 / (m 2 (×24h×0.1MPa), WTR unit is g / m 2 ×24h.

[0145] Table 1

[0146] Examples OTR WTR Haze Reflective layer reflectivity Example 11 9 5 5% 32% Example 12 2 1.8 6% 35% Example 13 0.4 0.3 4% 28% Example 14 1.4 1.3 5% 31% Example 15 0.5 0.4 7% 27% Example 16 1.3 1.2 5% 25% Example 17 10 4 5% 24% Example 18 0.3 0.5 4% 32% Example 19 1.5 1.2 6% 31% Example 20 8 4 7% 35% Example 21 0.3 0.3 5% 37% Example 22 1.7 2 4% 33% Example 23 7 3 8% 28% Example 24 10 3 5% 29% Example 25 0.4 0.3 6% 29%

[0147] The printing quality was visually inspected, with the absence of obvious (visible) defects as the standard. The results were all considered acceptable.

[0148] The UV wavelength absorption tests of each embodiment in Table 1 were conducted using GB / T19394-2003. The results showed that all ultraviolet rays in the range of 300~400nm were completely blocked. The test results are shown in Table 2, and the values ​​in Table 2 are percentages.

[0149] Table 2

[0150] Example 300 nm 310 nm 320 nm 330 nm 340 nm 350 nm 360 nm 370 nm 380 nm 390 nm 400 nm 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

[0151] In turn, the high-temperature cooking grade adhesive layer / semi-high-temperature cooking grade adhesive layer / water cooking 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 1-15 can all achieve full barrier of ultraviolet light below wavelength 400 nm. The modified barrier layer can also assist in improving oil resistance, acid and alkali resistance, radiation resistance and wear resistance. When the reflective layer is affected by light, it can reflect the specific light corresponding to the discoloration of the reflective layer, reducing the adverse effects of different light on the contents, especially food. When the ink layer and the reflective layer have different discoloration types, the ink printed text or pattern can be more eye-catching.

[0152] The same haze reflectance test was performed on examples 1-10, and the results are shown in Table 3. The same ultraviolet wavelength absorption test was also performed on examples 1-10, and the results are shown in Table 4. The values shown in Table 4 are percentages.

[0153] Table 3

[0154] Example Haze Reflective layer reflectivity 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%

[0155] Table 4

[0156] Example 300 nm 310 nm 320 nm 330 nm 340 nm 350 nm 360 nm 370 nm 380 nm 390 nm 400 nm 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

[0157] It is worth noting that the discoloration transparent referred to in the present application refers to a color structure similar to, for example, copper sulfate solution, which has the characteristics of transparency (referring to at least the light corresponding to the color of the reflective layer can penetrate).

[0158] The above only describes the preferred embodiments of the present application. It should be noted that for ordinary skilled persons in the technical field, without departing from the technical principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A transparent film with high UV barrier properties, characterized in that: The following are set from the outside in: Barrier layer, the barrier layer comprising a film coated with polyvinylidene chloride on one side of the barrier layer away from the adhesive layer, AlO x One of the following: modified membrane and SiO2 modified membrane; An ink layer and a barrier layer cover the ink layer, wherein the ink layer is a diarylethylene film B; The adhesive layer is prepared by coating and laminating a transparent, boil-resistant adhesive. The intermediate layer is a functional film layer, including at least one of NY, PET, BOPE, and MDOPE; The reflective layer is a diarylethylene film A; The heat-sealing layer is a PP or PE film with uniformly dispersed UV-resistant particles; The bottom of the barrier layer and the ink layer are bonded to the intermediate layer through an adhesive layer, and the intermediate layer, the reflective layer and the heat-sealing layer are heat-pressed together. The diarylethylene film A and the diarylethylene film B reflect different colors; 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。 2. The UV-resistant high-barrier transparent film according to claim 1, characterized in that: The adhesive layer is one of the following: water-boiling grade adhesive, semi-high temperature cooking grade adhesive, and high temperature cooking grade adhesive.

3. The UV-resistant high-barrier transparent film according to claim 1, characterized in that, The preparation method of the diarylethylene membrane includes the following steps: S1, weigh 5-20 parts of diarylethene photochromic compound, 150-200 parts of ethyl acetate-water solution, and 1-5 parts of surfactant by weight and mix well; S2, heat the mixture obtained in S1 to 40-60 degrees Celsius and keep it at that temperature for 1-2 hours to prepare the active intermediate; S3, the active intermediate obtained in S2 is coated onto the surface of at least one of the adjacent layers and dried at 60-80 degrees Celsius.

4. The UV-resistant high-barrier transparent film according to claim 3, characterized in that: The diarylethylene 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.

5. The UV-resistant high-barrier transparent film according to claim 3, characterized in that: In step S3, the surface of at least one of the adjacent layers of the diarylethylene membrane is activated by heat treatment at 40~50°C for more than 1 hour.

6. The UV-resistant high-barrier transparent film according to claim 3 or 5, characterized in that: The diarylethylene film has a light transmittance of >95% and a haze of <5%.

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