Multi-medium multi-layer high-brightness transparent reflective film and preparation method and application thereof

Abstract

The invention discloses a multi-medium multi-layer high-brightness transparent reflective film and a preparation method and application thereof, and relates to the technical field of reflective materials.The multi-medium multi-layer high-brightness transparent reflective film comprises a bead planting film, anti-reflection layers and reflection layers, the anti-reflection layers and the reflection layers are alternately arranged on the bead planting film in a stacked mode, and the anti-reflection layers or the reflection layers serve as the innermost layer; the reflecting layer is used as the outermost layer; through the design of the multi-medium multi-layer coating structure, the reflectivity of the reflective material in the visible light and near-infrared light range can be remarkably improved, and various application scenes with high reflectivity requirements are met; and the brightness and transparency of the reflective film can be obviously improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of reflective material, in particular to a multi-medium multi-layer high-brightness transparent reflective film and a preparation method and application thereof. BACKGROUND

[0002] Reflective films are widely used in traffic safety equipment, stickers, clothing and other fields. Its main principle is to return reflected light or refracted light to the light source direction through reflection and refraction of light, thereby achieving the effect of reflecting light. The reflective films on the market at present mainly have the following three types: The first type of reflective film is to glue on a PET or PE base film and adhere glass microbeads of different particle sizes. Although this reflective film is relatively transparent, its brightness is low (generally 2~7 cd / lx / m²), and its application scenarios are very limited.

[0003] The second type of reflective film is to glue on a PET or PE base film and adhere glass microbeads with a refractive index of 1.90~1.93, and then vacuum deposit a layer of aluminum film on the surface of the base film. Although the ordinary aluminum film has good reflective effect, the surface of the reflective film presents silver-white color, which is not transparent. If other colors are compounded later, the effect of compounding longer wavelength visible light colors (such as red, orange and yellow) will be slightly better than that of compounding shorter wavelength visible light colors (such as cyan, blue, purple and white), and the multi-color compounding process precision is very difficult to accurately control due to the instability of the process, which cannot meet the customer's selection of color diversity, and cannot be mass-produced.

[0004] The third type of reflective film is to glue on a PET or PE base film and adhere glass microbeads with a refractive index of 1.90~1.93, and then vacuum deposit a layer of zinc sulfide target material on the surface of the base film. The transparency of this reflective film is better than that of the reflective film plated with metal silver, but it still presents obvious yellow or other colors, and the brightness is not high (the highest brightness is about 100 cd / lx / m²), and the application scenarios are limited.

[0005] Therefore, it is necessary to design a reflective film that can maintain the transparency of the film surface itself while having high-brightness reflective effect. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a preparation method of a multi-medium multi-layer high-brightness transparent reflective film, which obtains a high-brightness transparent reflective film by alternately stacking an antireflection layer and a reflection layer on a beaded film by a vacuum deposition method.

[0007] The technical problem to be solved by the present application is solved by the following technical solution: One of the purposes of the present application is to provide a multi-medium multi-layer high-brightness transparent reflective film, which comprises a beaded film and a plurality of layers of antireflection layers and reflective layers alternately stacked on the beaded film, with the antireflection layer or the reflective layer as the innermost layer and the reflective layer as the outermost layer.

[0008] The present application achieves the common improvement of brightness and transparency by stacking the antireflection layer and the reflective layer. The reflective film can be a three-layer structure of beaded film-antireflection layer 1-reflective layer 1, a four-layer structure of beaded film-reflective layer 1-antireflection layer 1-reflective layer 2, a five-layer structure of beaded film-antireflection layer 1-reflective layer 1-antireflection layer 2-reflective layer 2, a six-layer structure of beaded film-reflective layer 1-antireflection layer 1-reflective layer 2-antireflection layer 2-reflective layer 3, a seven-layer structure of beaded film-antireflection layer 1-reflective layer 1-antireflection layer 2-reflective layer 2-antireflection layer 3-reflective layer 3, etc., with the reflective layer as the outermost layer of the reflective film and the innermost layer in contact with the beaded film being the antireflection layer or the reflective layer.

[0009] Further, the beaded film comprises a base film and glass microbeads uniformly distributed on the base film. The base film is one or more of polyethylene (PE) film, polyester (PET) film, etc. The glass microbeads are uniformly distributed on the base film by coating glue on the base film or heating the base film.

[0010] Further, the antireflection layer is made of one or more of calcium fluoride (CaF2), barium fluoride (BaF2), lithium fluoride (LiF), magnesium fluoride (MgF2), magnesium oxide (MgO), aluminum oxide (Al2O3), aluminum fluoride (AlF3), cerium fluoride (CeF3), lanthanum fluoride (LaF3), etc.

[0011] Further, the reflective layer is made of one or more of zinc selenide (ZnSe), zinc oxide (ZnO), zinc sulfide (ZnS), titanium oxide (TiO2), zirconium oxide (ZrO2), cerium oxide (CeO2), etc.

[0012] Further, the antireflection layer and the reflective layer are made by vacuum evaporation. The coating prepared by vacuum evaporation has high purity and controllable thickness, and the vacuum evaporation equipment has a relatively simple structure, easy operation, high production efficiency, and is suitable for large-scale industrial production.

[0013] Further, the vacuum evaporation method includes resistance heating evaporation, electron beam heating evaporation, high-frequency induction heating evaporation, laser beam heating evaporation, arc heating evaporation, etc. Different evaporation methods are selected according to the melting points of different materials.

[0014] Further, the thickness of the antireflection layer is 60-150 nm. Of course, the thickness of the antireflection layer can be adjusted according to customer requirements.

[0015] Further, the thickness of the reflective layer is 20-80 nm. Of course, the thickness of the reflective layer can be adjusted according to customer requirements.

[0016] The second object of the present application is to provide a preparation method of a multi-medium multi-layer high-brightness transparent reflective film, comprising the following steps: S1, preparing an anti-reflection layer on the beaded film by a vacuum evaporation method; S2, preparing a reflective layer on the anti-reflection layer by a vacuum evaporation method to obtain a reflective film with a three-layer structure of beaded film-anti-reflection layer-reflective layer; S3, alternately stacking the anti-reflection layer and the reflective layer on the reflective film prepared in step S2 by a vacuum evaporation method to obtain a multi-layer high-brightness transparent reflective film.

[0017] Further, the vacuum degree of the vacuum evaporation is 10 -6 ~10 Pa, and the evaporation speed is 10-200 m / min. The vacuum degree is adjusted according to the thickness and material of the film layer.

[0018] The third object of the present application is to provide the application of the multi-medium multi-layer high-brightness transparent reflective film in the fields of traffic signs, outdoor advertising, solar concentration, industrial reflection, clothing and shoes, etc.

[0019] The present application has the following advantages: a. High reflectivity. The present application can significantly improve the reflectivity of the reflective material in the visible light and near-infrared light range through the multi-medium multi-layer film coating structure design, and the reflectivity can reach 95-100%, meeting the requirements of various application scenarios for high reflectivity.

[0020] b. High brightness. The present application can significantly improve the brightness of the reflective film through the multi-medium multi-layer film coating structure design. Under the condition of an observation angle of 0.2° and an incident angle of -4°, the retroreflective coefficient of the reflective film can reach 600 cd / lx / m 2 , while the retroreflective coefficient of ordinary transparent reflective film is about 100 cd / lx / m 2 .

[0021] c. High transparency. The present application can significantly improve the transparency of the reflective film through the multi-medium multi-layer film coating structure design, so the reflective film itself is transparent, which is convenient as a semi-finished product. According to customer needs, various colored products can be made in the later stage without worrying about the color of the evaporated metal film affecting the color requirements of the later processing materials.

[0022] d. Good adhesion. The adhesion between the beaded film and the film coating layer of the present application is strong, which can reduce the risk of film layer falling off and improve the reliability and service life of the product.

[0023] e. Excellent coating uniformity. By precisely controlling coating parameters such as evaporation power, evaporation rate, vacuum degree, and reaction gas flow rate during each coating process, this invention ensures uniform deposition of the film on the surface of the glass microspheres, improving the brightness consistency and quality stability of the product.

[0024] f. Cost-effectiveness and production efficiency. The coating method and equipment used in this invention are relatively mature and easy to industrialize. They can effectively control production costs and improve production efficiency while ensuring product quality. Attached Figure Description

[0025] Figure 1 Here are schematic diagrams of the reflective films prepared in Examples 1-13; Figure 2 These are schematic diagrams of the reflective films prepared in Examples 14-17; Figure 3 These are schematic diagrams of the reflective films prepared in Examples 18-31; Figure 4 The diagram shows the structure of the reflective film prepared in Examples 32-41. Detailed Implementation

[0026] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific embodiments and illustrations.

[0027] The beaded films used in the following examples and comparative examples are all from Night Vision New Materials Co., Ltd. Their structure, from bottom to top, consists of a PET film, a laminating adhesive, a PE film, and glass microspheres, with the glass microspheres partially embedded in the PE film (e.g., ...). Figures 1-3 (As shown). Among them, the PET film thickness is 50 μm; the laminating adhesive thickness is 2 μm; the PE film thickness is 35 μm; the glass microspheres have a particle size of 300~400 mesh and a refractive index of 1.90~1.93.

[0028] The following uses CaF2 and ZnSe as target materials to prepare reflective films using the method provided in this invention and then performs performance tests on them.

[0029] Example 1 Preparation of reflective film: a. Load the beaded film into the high vacuum evaporation equipment and place the evaporation target in the evaporation tank; b. Close the evaporation tank cover, then send the beaded film into the vapor deposition chamber, close the chamber door, ensure the vapor deposition chamber is sealed, and turn on the equipment to evacuate the vacuum. c. Connect the power supply to the evaporation tank and heat the target material to the evaporation temperature. When the vacuum degree reaches 6.0 × 10⁻⁶... -2 After Pa, open the evaporator cover; d. Start the winding system and wind up at a constant speed (winding speed is the same as the vapor deposition speed). After winding, the reflective film is obtained.

[0030] Examples 2-13 The reflective film was prepared according to the method of Example 1, except that the evaporation rate was adjusted, as shown in Table 1.

[0031] The retroreflection coefficients of the reflective films prepared in Examples 1-13 were measured under the conditions of an observation angle of 0.2° and an incident angle of -4°. The results are shown in Table 1.

[0032] Table 1 As shown in Table 1, the thickness of the anti-reflective layer and the reflective layer affects the brightness of the reflective film. The brightness of the anti-reflective layer and the reflective layer is not directly proportional to the thickness of the reflective film. Therefore, it is necessary to control the thickness of the anti-reflective layer and the reflective layer to prepare a high-brightness reflective film.

[0033] Comparative Examples 1-7 The reflective film was prepared according to the method of Example 1, except that only the reflective layer was deposited, as shown in Table 2.

[0034] The retroreflection coefficients of the reflective films prepared in Comparative Examples 1 to 7 were measured under the conditions of an observation angle of 0.2° and an incident angle of -4°. The results are shown in Table 2.

[0035] Table 2 As shown in Tables 1 and 2, compared with reflective films containing only a reflective layer, adding an anti-reflective layer between the beaded film and the reflective layer will significantly improve the brightness of the reflective film. However, the thickness of the anti-reflective layer and the reflective layer needs to be controlled, otherwise a high-brightness reflective film cannot be obtained.

[0036] Examples 14-17 The reflective film was prepared according to the method of Example 1, except that a reflective layer 1, an anti-reflection layer 1, and a reflective layer 2 were prepared sequentially on the plant film, as shown in Table 3.

[0037] The retroreflection coefficients of the reflective films prepared in Examples 14-17 were measured under the conditions of an observation angle of 0.2° and an incident angle of -4°. The results are shown in Table 3.

[0038] Table 3 As shown in Table 3, a high-brightness reflective film can also be prepared by using the reflective layer as the innermost layer in contact with the plant film.

[0039] Examples 18-31 The reflective film was prepared according to the method of Example 1, except that an antireflective layer 2 and a reflective layer 2 were prepared, as shown in Table 4.

[0040] The retroreflection coefficients of the reflective films prepared in Examples 18-31 were measured under the conditions of an observation angle of 0.2° and an incident angle of -4°. The results are shown in Table 4.

[0041] Table 4 As shown in Tables 1 and 4, alternating layers of antireflective and reflective layers on the beaded film can significantly improve the brightness of the reflective film. However, it is also necessary to control the thickness of each antireflective and reflective layer; otherwise, a high-brightness reflective film cannot be obtained.

[0042] Examples 32-41 The reflective film was prepared according to the method of Example 1, except that an anti-reflection layer 2, a reflective layer 2, an anti-reflection layer 3, and a reflective layer 3 were prepared, as shown in Table 5.

[0043] The retroreflection coefficients of the reflective films prepared in Examples 32-41 were measured under the conditions of an observation angle of 0.2° and an incident angle of -4°. The results are shown in Table 5.

[0044] Table 5 As shown in Tables 4 and 5, alternating superimposed layers of three anti-reflective and reflective layers on the beaded film can significantly improve the brightness of the reflective film. However, it is also necessary to control the thickness of each anti-reflective and reflective layer; otherwise, a high-brightness reflective film cannot be obtained.

[0045] The reflectivity and transparency of the reflective films prepared in Examples 1 to 41 were tested. The test results showed that the reflectivity and transparency of these reflective films were both above 95%, which indicates that the reflective film of the present invention has the characteristics of high brightness, high transparency and high reflectivity.

[0046] The reflective films prepared in Examples 1-41 were tested for mechanical properties and corrosion resistance. The test results are as follows: a. The retroreflection coefficient retention rate is ≥80% after 10,000 flexes, which meets the standards of GB / T 28468-2012 and EN 471; b. Abrasion resistance (Taber abrasion ≤10%); Bending radius ≤3 mm, no cracks, conforming to GB / T 18833-2012 standard; c. Drop hammer impact ≥5J; no breakage when bent at -30℃; no corrosion after 500 hours of salt spray, conforming to GB / T 23827-2021 and ASTM B117 standards.

[0047] In summary, the reflective film of the present invention not only has the characteristics of high brightness, high transparency and high reflectivity, but also has excellent mechanical properties and corrosion resistance.

[0048] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A multi-medium, multi-layer, high-brightness transparent reflective film, characterized in that: It includes a beaded film and multiple layers of antireflective and reflective layers that are alternately stacked on the beaded film, with the antireflective or reflective layer as the innermost layer and the reflective layer as the outermost layer.

2. The multi-medium, multi-layer, high-brightness transparent reflective film according to claim 1, characterized in that: The beaded membrane includes a base membrane and glass microspheres uniformly distributed on the base membrane.

3. The multi-medium, multi-layer, high-brightness transparent reflective film according to claim 2, characterized in that: The base film is one or more of PE film and PET film.

4. The multi-medium, multi-layer, high-brightness transparent reflective film according to claim 1, characterized in that: The antireflective layer is made of one or more of CaF2, BaF2, LiF, MgF2, MgO, Al2O3, AlF3, CeF3, and LaF3.

5. The multi-medium, multi-layer, high-brightness transparent reflective film according to claim 1, characterized in that: The reflective layer is made of one or more of ZnSe, ZnO, ZnS, TiO2, ZrO2, and CeO2.

6. The multi-medium, multi-layer, high-brightness transparent reflective film according to claim 1, characterized in that: The antireflective layer and the reflective layer are fabricated by vacuum evaporation.

7. The multi-medium, multi-layer, high-brightness transparent reflective film according to claim 1, characterized in that: The thickness of the antireflective layer is 60~150 nm; the thickness of the reflective layer is 20~80 nm.

8. The method for preparing the multi-medium, multilayer, high-brightness transparent reflective film according to any one of claims 1 to 7, characterized in that, Includes the following steps: S1. An antireflective layer is prepared on the beaded film by vacuum evaporation. S2. A reflective layer is prepared on the anti-reflection layer by vacuum evaporation to obtain a reflective film with a three-layer structure of beaded film-anti-reflection layer-reflective layer. S3. An antireflective layer and a reflective layer are alternately superimposed on the reflective film prepared in step S2 by vacuum evaporation to obtain a multi-medium, multi-layer, high-brightness transparent reflective film.

9. The preparation method according to claim 8, characterized in that: The vacuum degree of the vacuum evaporation is 10⁻⁶ to 10 Pa, and the evaporation rate is 10 to 200 m / min.

10. The application of the multi-medium multilayer high-brightness transparent reflective film according to any one of claims 1 to 7 or the multi-medium multilayer high-brightness transparent reflective film prepared by the preparation method according to any one of claims 8 to 9 in traffic signs, outdoor advertising, solar concentrators, industrial reflectors, and clothing and footwear.

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