High-performance peep-proof film and preparation method thereof

Abstract

The invention belongs to the technical field of peep-proof films, and particularly relates to a high-performance peep-proof film and a preparation method thereof. The peep-proof film comprises a base material layer, and the upper surface and the lower surface of the base material layer are covered with a first peep-proof structure layer and a second peep-proof structure layer respectively. The first peep-proof structure layer comprises a first peep-proof structure, a peep-proof unit is formed on the upper surface of the first peep-proof structure, and the space between the first peep-proof structure and the second peep-proof structure is filled with black glue to form a first black glue layer; the second peep-proof structure layer comprises a second peep-proof structure, and the two sides of the second peep-proof structure are coated with black glue to form second black glue layers. Wherein the black adhesive is prepared by mixing acrylic resin, an initiator, carbon black and diffusion particles. During preparation, the acrylic coating is cured on the upper surface of the base material layer to the peep-proof structure layer I; the acrylic coating is cured on the lower surface of the base material layer to obtain the peep-proof structure layer II. The peep-proof film disclosed by the invention is relatively good in light transmittance and capable of realizing 360-degree peep prevention.

Description

Technical Field

[0001] The invention belongs to the technical field of privacy films, and in particular relates to a high-performance privacy film and a preparation method thereof. Background Art

[0002] The principle of common privacy films on the market is to use ultra-fine blinds optical technology to make the content displayed on the screen visible only to the user from the front, with a viewing area of ​​60~90 degrees. Anyone watching from the sides can only see a dark screen. This can effectively protect commercial secrets and personal privacy, allowing users to use computers, mobile phones and other electronic products as they please in the office, on the road, in public places and in any environment.

[0003] However, the current anti-peep film products have a flat upper surface with low light transmittance. The brightness is extremely low under strong light during the day, which affects the visual effect. Moreover, it can only prevent peeping on the left and right sides, but not on the top and bottom. This leads to few application scenarios. For example, the current car-mounted central control requires 360° anti-peeping, that is, a product that can prevent peeping from the top, bottom, left and right. Summary of the invention

[0004] The present invention aims at addressing the deficiencies of the prior art and provides a high-performance privacy film and a preparation method thereof.

[0005] The technical solution of the present invention is as follows: In a first aspect, a high-performance privacy film is provided, including a substrate layer, wherein the upper and lower surfaces of the substrate layer are respectively covered with a privacy structure layer 1 and a privacy structure layer 2; the privacy structure layer 1 includes a privacy structure 1, wherein a privacy unit is formed on the upper surface of the privacy structure 1, and black glue is filled between the privacy structure 1 and the privacy structure 1 to form a black glue layer 1; the privacy structure layer 2 includes a privacy structure 2, wherein black glue is coated on both sides of the privacy structure 2 to form a black glue layer 2; The black glue is prepared by mixing acrylic resin, initiator, carbon black and diffusion particles. The preparation method of the diffusion particles includes the following steps: dispersing PMMA in anhydrous ethanol, adding a dispersant, stirring to obtain a diffusion particle solution, adding a vanadium dioxide solution and a nickel ferrite solution to the diffusion particle solution, adding a silane coupling agent after ultrasonic treatment, stirring to react, adding polyvinyl alcohol, stirring, and after the reaction is completed, centrifuging to obtain diffusion particles.

[0006] In some implementations, the first anti-peeping structure is a trapezoid, the height of the trapezoid is 65-85 μm, and the bottom of the trapezoid is 25-30 μm; the refractive index of the black plastic is 1.48-1.53.

[0007] In some implementations, an anti-peeping unit is formed on the upper surface of an anti-peeping structure, a groove is formed between the anti-peeping mechanism and the anti-peeping structure, a black glue layer is filled in the groove, the groove is an inverted trapezoid, the upper base of the trapezoid is 10-15μm, and the angle formed by the extension lines of the two waists of the trapezoid is the anti-peeping angle α, and the anti-peeping angle α is 1-5°.

[0008] In some implementations, the anti-peeping unit includes an anti-peeping unit 1, which is a triangular structure. The height of the triangle is 1-5μm, the vertex angle of the triangle is 90°, and the ranges of the remaining two internal angles of the triangle are 85-89° and 1-5° respectively. An inverted trapezoid is formed between the triangles, and the upper base of the trapezoid is 2-10μm.

[0009] In some implementations, the anti-peeping unit further includes an anti-peeping unit 2, which is a circular protrusion structure with a height of 1-5 μm. An inverted deformed trapezoid is formed between the circular protrusion structures, and the upper base of the deformed trapezoid is 2-10 μm.

[0010] In some implementations, the anti-peeping structure 1 and the anti-peeping structure 2 are not in the same direction on the horizontal plane, the angle β between the anti-peeping structure 1 and the anti-peeping structure 2 is 90°, the angle between the bottom surface of the anti-peeping structure 1 and the upper surface of the substrate layer is 0-10°, and the angle between the upper surface of the anti-peeping structure 2 and the lower surface of the substrate layer is 90-100°.

[0011] In some implementations, the height of the substrate layer is 25-100 μm, the substrate layer includes a substrate, and the material of the substrate includes PET, PC, and PVC; the upper and lower surfaces of the substrate are covered with a coating, and the coating is obtained by curing the coating. The preparation method of the coating includes the following steps: adding a water-based acrylic resin to a solvent, stirring evenly, adding a coupling agent, a curing agent and an anti-aging agent, continuing to stir, adding nanoparticles, and stirring to obtain a coating, wherein the nanoparticles include at least one of modified nanoparticles, nano-silicon dioxide, and nano-titanium dioxide.

[0012] In some implementations, the preparation method of modified nanoparticles includes the following steps: dispersing nano-silicon dioxide and nano-titanium dioxide in a mixture of anhydrous ethanol and deionized water, respectively, and ultrasonically treating to obtain a silicon dioxide solution and a titanium dioxide solution, respectively; adding the silicon dioxide solution dropwise into the titanium dioxide solution while stirring, adjusting the pH value of the solution, stirring to react, to obtain core-shell composite particles, re-dispersing the core-shell structure particles in anhydrous ethanol, adding a silane coupling agent, stirring to react, to obtain silane-modified composite particles; dispersing the silane-modified composite particles in polyethyleneimine, stirring to react, to obtain modified nanoparticles.

[0013] In a second aspect, a method for preparing the aforementioned high-performance privacy film is provided, comprising the following steps: A micro-concave roller with an anti-peeping unit and an anti-peeping structure 1 is engraved on a roller blank, and a chrome layer is formed on the surface of the micro-concave roller by chrome plating; an acrylic paint is applied to the upper surface of the substrate layer by hard pressure transfer using the micro-concave roller, and the anti-peeping structure layer 1 is obtained by curing; A micro-concave roller with a second anti-peeping structure is engraved on a roller blank, and a chrome layer is formed on the surface of the micro-concave roller by chrome plating; an acrylic paint is applied to the lower surface of the substrate layer by hard pressure transfer using the micro-concave roller, and cured to obtain the second anti-peeping structure layer; Applying black glue to the first anti-peeping structure and the first anti-peeping structure in the groove, and curing to obtain a first black glue layer; Black glue is applied to both sides of the second anti-peeping structure and solidified to obtain a second black glue layer.

[0014] The complete structure made through the aforementioned steps is a high-performance privacy film.

[0015] In some implementations, the thickness of the chromium layer is 0.1-0.5 μm, and the black glue is cured under ultraviolet light with an ultraviolet energy of 1000-1500 mJ / cm 2 .

[0016] In some implementations, white glue can be applied on the black glue, and then cured under ultraviolet light with an energy of 200-500 mJ / cm 2 , and obtain a white glue layer.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1. The anti-peep film of the present invention has better light transmittance, which can be increased by 3% to 10%. Therefore, when the anti-peep film is applied to a display screen, the display screen seen by the user has higher clarity.

[0018] 2. In the prior art, the anti-peeping viewing angle of the anti-peeping film is generally 28-30°. The anti-peeping viewing angle of the anti-peeping film of the present invention is within 28°, and has the advantage of 360° anti-peeping up, down, left, and right. Specifically, 1) the present invention restricts the specific parameters, reducing the anti-peeping viewing angle, 2) the present invention sets an anti-peeping structure layer 1 and an anti-peeping structure layer 2, and sets an anti-peeping unit on the anti-peeping structure 1, and the anti-peeping unit further increases the difficulty of viewing up, down, left, and right, 3) in addition, the anti-peeping structure 1 and the anti-peeping structure 2 are not in the same direction on the horizontal plane, and the angle β between the anti-peeping structure 1 and the anti-peeping structure 2 is 90°. The anti-peeping structure layer 1 is the top layer, the black glue is the visible area, and the anti-peeping structure layer 1 and the anti-peeping structure layer 2 are the light blocking area. With this arrangement, it is equivalent to that the four sides of the black glue (up, down, left, and right) are surrounded by the anti-peeping structure 1 and the anti-peeping structure 2. Except for the user, other people cannot see the visible area up, down, left, and right.

[0019] 3. The preparation method of the present invention is simple, easy to implement and control, and convenient for industrialization.

[0020] 4. The present invention optimizes the formula of the coating and black glue used for the substrate, and also modifies the nanoparticles in the coating used for the substrate, and modifies the diffusion particles in the black glue. High light transmittance materials and partial light absorbing materials are introduced into the above formula at the same time. Through reasonable formula, the balance of each component is achieved, the light diffusion intensity and uniformity of the material are balanced, and the mechanical properties of the material can be improved by the introduced light absorbing material. For example: the carbon black and diffusion particles in the black glue can better atomize the light source, improve the uniformity of the light source and the visibility of the screen, and the screen content can still be clearly seen even in the strong light environment outdoors. At the same time, it can reduce the stimulation of strong light reflection to the human eye, relieve visual fatigue, and play a role in eye protection.

[0021] The remaining more specific mechanisms are explained in detail in the examples. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The accompanying drawings are used to provide further understanding of the present invention and constitute a part of the specification. They are used to explain the present invention together with the embodiments of the present invention and do not constitute a limitation of the present invention.

[0023] In the attached picture: Figure 1 : is a schematic diagram of the overall structure of the anti-peeping film of the present invention; it should be noted that the black glue layer 1 and the anti-peeping unit are omitted, and the anti-peeping unit includes the anti-peeping unit 1 and the anti-peeping unit 2; Figure 2 is a schematic diagram of the side structure of the privacy film of the present invention; Figure 3 It is a side structural schematic diagram of the anti-peeping unit 1 of the present invention; Figure 4 It is a side structural schematic diagram of the second anti-peeping unit of the present invention; Figure 5 It is a schematic diagram of the positional relationship between the anti-peeping structure 1 and the anti-peeping structure 2 of the present invention. It should be noted that in order to facilitate clear observation of the angle setting, the substrate layer is omitted, and the number of the anti-peeping structure 1 and the anti-peeping structure 2 is 1.

[0024] Marked in the figure: 1. Base material layer, 2. Anti-peeping structure one, 3. Anti-peeping unit one, 4. Anti-peeping unit two; 5. Black glue layer one, 6. Black glue layer two, 7. Anti-peeping structure two, 8. Groove one, 9. Groove two. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments and the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. The experimental methods used below are conventional methods unless otherwise specified, and the materials, reagents, parts, etc. used, unless otherwise specified, can all be obtained from commercial sources.

[0026] Example 1 The preparation method of the high-performance privacy film includes the following specific steps: 1. Preparation of substrate layer 1: Select a suitable substrate, and attach a coating to both the front and back sides of the substrate to obtain a substrate layer 1 with a thickness of 25-100 μm.

[0027] 2. Prepare a micro-concave roller with an anti-peeping unit and an anti-peeping structure 2: Take a stainless steel or metal copper or nickel roller blank and perform diamond engraving to carve out a micro-concave roller with an anti-peeping unit and an anti-peeping structure 2, and then perform chrome plating on the surface of the micro-concave roller, with a chromium layer of 0.1 μm.

[0028] 3. Prepare a micro-concave roller with an anti-peeping structure 27: Take a stainless steel or metal copper or nickel roller blank and perform diamond engraving to carve out a micro-concave roller with an anti-peeping structure 27, and then perform chrome plating on the surface of the micro-concave roller, with a chromium layer of 0.1μm.

[0029] 4. Preparation of black glue: Mix acrylic resin, initiator, carbon black and diffusion particles at a high speed according to the proportion to obtain black glue. The refractive index of black glue is 1.48-1.53.

[0030] 5. Preparation of anti-peep structure layer 1: The micro-concave roller with the anti-peep unit and the anti-peep structure 1 2 applies the acrylic paint on the upper surface of the substrate layer 1 by hard pressure transfer, and cures it under ultraviolet light to obtain the anti-peep structure layer 1. The acrylic paint of the anti-peep structure layer 1 uses a conventional acrylic paint. The acrylic paint is a light absorbing material or a light shielding agent.

[0031] 6. Preparation of the second anti-peep structure layer: The micro-concave roller with the second anti-peep structure 7 applies the acrylic paint on the lower surface of the substrate layer 1 by hard pressure transfer, and cures it under ultraviolet light to obtain the second anti-peep structure layer. The acrylic paint of the second anti-peep structure layer uses a conventional acrylic paint, which is a light-absorbing material or a light-shielding agent.

[0032] 7. Prepare black glue layer: The black glue layer includes black glue layer 1 5 and black glue layer 2 6. Apply the black glue to the groove 1 8 between the anti-peeping structure 1 2 and the anti-peeping structure 1 2 through a metal roller, and cure under ultraviolet light, the ultraviolet energy of which is 1000-1500 mJ / cm 2 , and obtain a black glue layer 5. No black glue is applied on the anti-peep unit.

[0033] The black glue is applied to both sides of the anti-peeping structure 7 by a metal roller, including the groove 9 between the anti-peeping structure 7 and the anti-peeping structure 7, and cured under ultraviolet light, and the ultraviolet energy is 1000~1500mJ / cm 2 , and obtain the second black gel layer 6.

[0034] It should be noted that, for the anti-peeping structure layer 1, only the groove 1 8 is filled with black glue, and one side of the outermost anti-peeping structure 1 2 does not contact the black glue, that is, the outermost side is the anti-peeping structure 1 2, or the head and tail are the anti-peeping structure 1 2. For the anti-peeping structure layer 2, the outermost anti-peeping structure 2 7 is filled with black glue, that is, the outermost side is the black glue layer 2 6, or the head and tail are the black glue layer 2 6. Figure 1 It can be clearly seen.

[0035] 8. Prepare a white glue layer (optional): In order to further enhance light transmittance, white glue can be applied on the black glue and then cured under ultraviolet light. The ultraviolet energy is 200~500mJ / cm 2 , and obtain a white glue layer.

[0036] Through the above steps, a high-performance privacy film is finally obtained. The structure of the high-performance privacy film is shown in Figure 2. Figure 1-5 , specifically as follows: from top to bottom, they are anti-peeping structure layer 1, substrate layer 1, and anti-peeping structure layer 2. That is, when the anti-peeping film is used, the front side is the side where the anti-peeping structure layer 1 is located, and the side where the anti-peeping structure layer 2 is located is the back side.

[0037] The vinyl (i.e., vinyl layer 1 5 and vinyl layer 2 6) is the visible area, and the anti-peep structure layer 1 and the anti-peep structure layer 2 are the light blocking areas. With this arrangement, the vinyl is surrounded on all sides (up, down, left, and right) by the anti-peep structure 1 2 and the anti-peep structure 2 7. The anti-peep unit further blocks the line of sight and the visual difficulty of bystanders. Except for the user, bystanders cannot see the visible area from top to bottom, left to right.

[0038] Reference Figure 1 and Figure 2 The anti-peeping structure layer 1 includes an anti-peeping structure 2, which is a trapezoid, with a height d3 of 65-85 μm and a bottom d2 of 25-30 μm.

[0039] Reference Figure 2 , the number of the anti-peeping structures 2 is multiple, the anti-peeping structures 2 are parallel to each other, thereby forming a groove 8, and the black glue layer 5 is filled in the groove 8. The groove 8 is an inverted trapezoid, and the upper base d1 of the trapezoid is 10-15μm. In addition, the anti-peeping angle α is 1-5°, and the anti-peeping angle α is the angle α formed by the extension lines of the two waists of the groove 8 trapezoid.

[0040] Reference Figure 2-Figure 4 The anti-peeping unit is formed on the upper surface of the anti-peeping structure 2. The anti-peeping unit is a plurality of anti-peeping units 1 3 or anti-peeping units 2 4. The anti-peeping unit 1 3 is a triangular structure, and the anti-peeping unit 2 4 is a circular protruding structure.

[0041] Reference Figure 3When the anti-peeping unit is anti-peeping unit 13, the height of the triangle is 1-5μm, the vertex angle θ1 of the triangle is 90°, and the remaining two internal angles θ3 and θ2 of the triangle are in the range of 85-89° (θ3) and 1-5° (θ2). For multiple triangles, an inverted trapezoid is formed between the triangles, and the upper base d4 of the trapezoid is 2-10μm.

[0042] Reference Figure 4 When the anti-peeping unit is the anti-peeping unit 24, the height d7 of the circular protrusion structure is 1-5μm. For multiple circular protrusion structures, an inverted deformed trapezoid is formed between the circular protrusion structures, and the two sides of the deformed trapezoid are arc-shaped. The upper base d6 of the deformed trapezoid is 2-10μm.

[0043] Reference Figure 1 The second anti-peeping structure layer includes a second anti-peeping structure 7, the number of the second anti-peeping structure 7 is multiple, the second anti-peeping structure 7 is parallel to the second anti-peeping structure 7, thereby forming a second groove 9, and the second black glue layer 6 is filled in the second groove 9. Except that the second anti-peeping structure 7 does not have an anti-peeping unit, the parameters of the second anti-peeping structure 7 are the same as those of the first anti-peeping structure 2, and the parameters of the second groove 9 are the same as those of the first groove 8.

[0044] It should be noted that the anti-peeping structure 1 2 and the anti-peeping structure 2 7 are not in the same direction on the horizontal plane. Figure 5 In order to clearly understand the angle setting, the substrate layer is omitted and the anti-peeping structure 1 2 and the anti-peeping structure 2 7 are directly observed. The angle β between the anti-peeping structure 1 2 and the anti-peeping structure 2 7 is 90°. In addition, the angle between the bottom surface of the anti-peeping structure 1 2 and the upper surface of the substrate layer 1 is 0-10°, and the angle between the upper surface of the anti-peeping structure 2 7 and the lower surface of the substrate layer 1 is 90-100°.

[0045] Example 2 The modified nanoparticles are prepared in the following steps: By weight, the raw materials are as follows: Nanosilica: 20 nm, Sigma-Aldrich, 99.5% purity.

[0046] Nano titanium dioxide (TiO 2 ): 10 nm, Sigma-Aldrich, 99.5% purity.

[0047] Silane coupling agent: Silane coupling agent KH-570, 98% purity.

[0048] Polyethyleneimine: branched polyethyleneimine, Sigma-Aldrich, molecular weight 1200 g / mol.

[0049] Anhydrous ethanol: 99% purity.

[0050] Preparation of modified nanoparticles: 5 parts by weight of nano silicon dioxide and 5 parts of nano titanium dioxide were dispersed in 50 mL of a mixture of anhydrous ethanol and deionized water, and ultrasonically treated for 30 minutes using an ultrasonic disperser to obtain a silicon dioxide solution and a titanium dioxide solution, respectively. In the mixture of anhydrous ethanol and deionized water, the volume ratio of anhydrous ethanol to deionized water was 1:1.

[0051] The silica solution was slowly added dropwise into the titanium dioxide solution while stirring, the pH value of the solution was adjusted to 8-9 with ammonia water, and then stirred at 60° C. for 3 hours to obtain core-shell composite particles, which were filtered, washed, and dried for later use.

[0052] The core-shell structure particles were redispersed in 50 mL of anhydrous ethanol, 2 parts of a silane coupling agent were added, and the mixture was stirred and reacted at 70° C. for 2 hours to form a first coating layer, thereby obtaining silane-modified composite particles.

[0053] The silane-modified composite particles were dispersed in 50 mL of polyethyleneimine, ultrasonically dispersed for 15 minutes, and then stirred and reacted at 60°C for 4 hours to form a second coating layer. After the reaction was completed, the particles were filtered, washed, and dried to obtain modified nanoparticles.

[0054] It should be noted that when preparing modified nanoparticles, nano-silicon dioxide is used as the core, nano-titanium dioxide is coated on the outer layer, and the surface is further double-modified by functional molecules to form a core-shell composite nanostructure, that is, core-shell composite particles. Core-shell composite particles reduce light scattering through silicon dioxide, titanium dioxide enhances UV resistance, and at the same time inhibits the photocatalytic effect and high scattering characteristics of titanium dioxide through the composite structure, thereby exerting the synergistic effect of silicon dioxide and titanium dioxide to improve optical transmittance and durability. A coating layer is formed outside the core-shell composite particles, and the coating layer is divided into two layers. The inner layer: the silane coupling agent forms a chemically bonded stable coating layer. The outer layer: polyethyleneimine forms a flexible coating layer to achieve a balance between mechanical properties and flexibility. Polyethyleneimine provides amino and amide functional groups to enhance interfacial activity and binding force. Polyethyleneimine forms a uniform coating layer on the surface of nanoparticles to optimize the dispersibility, binding force and mechanical properties of the particles. Polyethyleneimine can further achieve new structures and new functions by synergistically coating with silane coupling agents, providing modified nanoparticles with high hardness, high flexibility and anti-aging properties. Polyethyleneimine coating can also further weaken the photocatalytic effect and high scattering characteristics of nano titanium dioxide, prevent the coating from generating free radicals under the action of ultraviolet rays, enhance the coating's anti-ultraviolet and weather resistance, extend the coating's life, and improve light transmittance.

[0055] Example 3 In this embodiment, the specific preparation steps of the substrate layer 1 are given: Preparation of substrate layer 1: 1. The material of the substrate is PET (polyethylene terephthalate) or PC (polycarbonate) or PVC (polyvinyl fluoride).

[0056] 2. Raw materials for preparing coatings: By weight, the raw materials are as follows: Water-based acrylic resin: 60-100 parts, Dow PRIMAL™ AC-261; Coupling agent: 1-5 parts, silane coupling agent KH-570, 98% purity; Modified nanoparticles: 5-15 parts of the modified nanoparticles prepared in Example 2; Solvent: 8-10 parts, dimethyl sulfoxide, 99% purity.

[0057] Curing agent: 1-5 parts, water-based curing agent, Dow RESIN HF-05.

[0058] Anti-aging additive: 0.5-2 parts, UV absorber, UV-531, 99% purity.

[0059] 3. Prepare coating and substrate layer 1 using raw materials: add 80 parts of waterborne acrylic resin to 8 parts of solvent, stir evenly, add 3 parts of coupling agent, 2 parts of curing agent and 1 part of anti-aging agent, continue stirring, add 10 parts of modified nanoparticles in batches, stir for 30 minutes using a high-speed stirrer, control the speed at 1000-1500rpm, obtain coating, use a coating machine to evenly apply the coating to the front and back of the substrate, the coating thickness is 1-5μm, dry and solidify after coating, and obtain substrate layer 1. PET is selected as the substrate.

[0060] It should be noted that the water-based acrylic resin, as the main body of the coating, provides excellent flexibility and adhesion. The coupling agent improves the bonding force between the coating and the substrate and enhances the adhesion performance. The modified nanoparticles can improve the hardness and optical properties of the coating, reduce light scattering, and improve light transmittance. The modified nanoparticles prepared in Example 2 are core-shell composite structures, which are filled in the resin, enhance the hardness of the resin matrix, reduce light scattering, and improve the UV resistance and transparency of the coating. The high flexibility of the water-based acrylic resin is combined with the high hardness of the modified nanoparticles to provide a balance between hardness and flexibility, and enhance the impact resistance and scratch resistance of the coating.

[0061] Example 4 In this example, the diffusion particles were prepared: 1. Prepare the raw materials: PMMA: polymethyl methacrylate, Sigma-Aldrich, 99% purity.

[0062] Vanadium dioxide particles: 50-100 nm, Sigma-Aldrich, 99% purity.

[0063] Nickel ferrite particles: 30-50 nm, Sigma-Aldrich, 99% purity.

[0064] Dispersant: BYK-333, BYK.

[0065] Silane coupling agent: Silane coupling agent KH-570, 98% purity.

[0066] Anhydrous ethanol: 99% purity.

[0067] Polyvinyl alcohol: Sigma-Aldrich, 99% purity.

[0068] 2. Preparation of diffusion particles: 85 parts of PMMA were dispersed in 50 mL of anhydrous ethanol, 1 part of a dispersant was added, and the mixture was stirred for 10 minutes using a magnetic stirrer until uniform, thereby obtaining a diffusion particle solution.

[0069] Three parts of vanadium dioxide particles and two parts of nickel ferrite particles were ultrasonically dispersed in three parts of anhydrous ethanol to obtain a vanadium dioxide solution and a nickel ferrite solution, respectively. The ultrasonic conditions were: power 500 W, time 15 minutes.

[0070] The vanadium dioxide solution and the nickel ferrite solution were slowly added to the diffusion particle solution in sequence, and ultrasonic treatment was performed at 500W for 20 minutes while stirring. Then, 2 parts of silane coupling agent were added, and the reaction was stirred at 60°C for 2 hours. 1 part of polyvinyl alcohol was added and stirred at a low speed for 30 minutes. After the reaction was completed, the mixture was centrifuged at 8000g for 10 minutes to remove the solvent and excess dispersant. After separation, it was dried to obtain diffusion particles of 3-5μm.

[0071] It should be noted that PMMA, as the main body of the diffusion particles, provides high light transmittance and basic optical diffusion performance. Vanadium dioxide particles and nickel ferrite particles form a functional layer on PMMA through the action of dispersants and silane coupling agents. Vanadium dioxide particles and nickel ferrite particles work together to prevent excessive scattering of visible light. Polyvinyl alcohol is further coated on the surface of the particles to enhance the mechanical stability and dispersion properties of the particles, so that they can be better dispersed in black glue. In order to prevent vanadium dioxide particles and nickel ferrite particles from affecting the light transmittance of PMMA, the ratio of each component of the formula is optimized to achieve a balance among the components.

[0072] Example 5 The specific steps of preparing the black glue are as follows: 85 parts of acrylic resin, 1 part of initiator, 3 parts of carbon black, and 11 parts of diffusion particles are placed in a container, and stirred and mixed at a high speed of 1200-1500 rpm to obtain the black glue. The refractive index of the black glue is 1.48-1.53.

[0073] Among them, acrylic resin: Dow PRIMAL™ AC-261; Photoinitiator: Lencolo 5033; Carbon black particles: Japan Mitsubishi MA100 carbon black; Diffusion particles: the diffusion particles prepared in Example 4.

[0074] It should be noted that the diffusion particles can scatter light, and the carbon black absorbs excess light. In order to avoid excessive carbon black affecting the transmittance and uniformity of light transmittance, the ratio of each component of the formula is optimized. The carbon black is evenly distributed in the acrylic resin matrix, which can improve the optical stability and mechanical properties of the black glue.

[0075] Example 6 The method of Example 1 is used, the material of Example 3 is used to prepare the substrate layer 1, and the black glue of Example 5 is used to prepare the black glue layer 5 and the black glue layer 6. No white glue layer is prepared, and the anti-peeping unit is the anti-peeping unit 3, to prepare a high-performance anti-peeping film.

[0076] It should be noted that in this embodiment, in order to avoid excessive light reflection and "soften" the light of the privacy film, no white glue layer is prepared. According to actual needs, if stronger light is required, a white glue layer can be superimposed on the black glue of the present invention.

[0077] Comparative Example 1 Different from Example 6, this example uses homemade black glue. The specific steps of preparing black glue are as follows: 85 parts of acrylic resin, 1 part of initiator, 3 parts of carbon black, and 11 parts of diffusion particles are put into a container, and stirred and mixed at a high speed of 1200-1500 rpm to obtain black glue.

[0078] Among them, acrylic resin: Dow PRIMAL™ AC-261; Photoinitiator: Lencolo 5033; Carbon black particles: Japan Mitsubishi MA100 carbon black; Diffusion particles: polymethyl methacrylate, Sigma-Aldrich, 99% purity.

[0079] Then, the method of Example 1 is used to prepare the substrate layer 1 using the material of Example 3, and the black glue prepared in this example is used to prepare the black glue layer 1 5 and the black glue layer 2 6. No white glue layer is prepared, and the anti-peeping unit is the anti-peeping unit 1 3, thereby preparing an anti-peeping film.

[0080] Comparative Example 2 Different from Example 6, the substrate is not coated with a coating, and the rest is the same as Example 6 to prepare an anti-peep film.

[0081] The privacy films of Example 6, Comparative Example 1 and Comparative Example 2 were tested: Testing method: According to GB / T 2410-2008 Determination of light transmittance and haze of transparent plastics, use a light transmittance tester to test the brightness transmittance and haze of the product. The results are shown in Table 1.

[0082] Table 1

[0083] Analysis: The light transmittance of Comparative Examples 1 and 2 is between 55% and 65%, and the light transmittance of the high-performance privacy film prepared by the present invention is between 68% and 75%. The light transmittance of the privacy film of the present invention is increased by 3% to 10%. When the privacy film is applied to a display screen, the user sees a higher definition of the display screen and has a better privacy protection effect.

[0084] In Comparative Examples 1 and 2, the materials were adjusted. In Comparative Example 1, the optimized diffusion particles were not added, and the synergistic effect of the optical properties between the materials was weak. In Comparative Example 2, the substrate layer 1 lacked the protection and optimization of the functional coating, the optical non-uniformity was enhanced, the haze increased significantly, and the excessive haze affected the transmittance. Example 6 can better balance the haze and transmittance.

[0085] In general, the high-performance privacy film prepared by the present invention can achieve a 360° privacy protection effect while taking into account a better light transmittance. When the high-performance privacy film is applied to the screen, it can improve the uniformity of the light source of the screen. The carbon black and diffusion particles in the black glue can better atomize the light source and improve the visibility of the screen. Even in the outdoor strong light environment, the screen content can still be clearly seen. At the same time, it reduces the stimulation of strong light reflection to the human eye, relieves visual fatigue, and plays a role in eye protection.

[0086] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. High-performance privacy film, characterized in that: It includes a substrate layer, the upper and lower surfaces of the substrate layer are respectively covered with an anti-peeping structure layer 1 and an anti-peeping structure layer 2; the anti-peeping structure layer 1 includes an anti-peeping structure 1, an anti-peeping unit is formed on the upper surface of the anti-peeping structure 1, and black glue is filled between the anti-peeping structure 1 and the anti-peeping structure 1 to form a black glue layer 1; the anti-peeping structure layer 2 includes an anti-peeping structure 2, and black glue is coated on both sides of the anti-peeping structure 2 to form a black glue layer 2; The black glue is prepared by mixing acrylic resin, initiator, carbon black and diffusion particles. The preparation method of the diffusion particles includes the following steps: dispersing PMMA in anhydrous ethanol, adding a dispersant, stirring to obtain a diffusion particle solution, adding a vanadium dioxide solution and a nickel ferrite solution to the diffusion particle solution, adding a silane coupling agent after ultrasonic treatment, stirring to react, adding polyvinyl alcohol, stirring, and after the reaction is completed, centrifuging to obtain diffusion particles.

2. The high-performance privacy film according to claim 1, characterized in that: The first anti-peeping structure is a trapezoid, the height of the trapezoid is 65-85 μm, and the bottom of the trapezoid is 25-30 μm; the refractive index of the black plastic is 1.48-1.

53.

3. The high-performance privacy film according to claim 1, characterized in that: An anti-peeping unit is formed on the upper surface of the anti-peeping structure, a groove is formed between the anti-peeping mechanism and the anti-peeping structure, a black glue layer is filled in the groove, the groove is an inverted trapezoid, the upper base of the trapezoid is 10-15μm, and the angle formed by the extension lines of the two waists of the trapezoid is the anti-peeping angle α, and the anti-peeping angle α is 1-5°.

4. The high-performance privacy film according to claim 1, characterized in that: The anti-peeping unit includes an anti-peeping unit 1, which is a triangular structure. The height of the triangle is 1-5μm, the vertex angle of the triangle is 90°, and the ranges of the remaining two internal angles of the triangle are 85-89° and 1-5° respectively. An inverted trapezoid is formed between the triangles, and the upper base of the trapezoid is 2-10μm.

5. The high-performance privacy film according to claim 1, characterized in that: The anti-peeping unit also includes an anti-peeping unit 2, which is a circular protruding structure with a height of 1-5 μm. An inverted deformed trapezoid is formed between the circular protruding structures, and the upper base of the deformed trapezoid is 2-10 μm.

6. The high-performance privacy film according to claim 1, characterized in that: The anti-peeping structure 1 and the anti-peeping structure 2 are not in the same direction on the horizontal plane, the angle β between the anti-peeping structure 1 and the anti-peeping structure 2 is 90°, the angle between the bottom surface of the anti-peeping structure 1 and the upper surface of the substrate layer is 0-10°, and the angle between the upper surface of the anti-peeping structure 2 and the lower surface of the substrate layer is 90-100°.

7. The high-performance privacy film according to claim 1, characterized in that: The height of the substrate layer is 25-100 μm, and the substrate layer includes a substrate, and the material of the substrate includes PET, PC, and PVC; the upper and lower surfaces of the substrate are covered with a coating, and the coating is obtained by curing the coating. The preparation method of the coating includes the following steps: adding a water-based acrylic resin to a solvent, stirring evenly, adding a coupling agent, a curing agent and an anti-aging additive, continuing to stir, adding nanoparticles, and stirring to obtain a coating, wherein the nanoparticles include at least one of modified nanoparticles, nano-silicon dioxide, and nano-titanium dioxide.

8. The high-performance privacy film according to claim 7, characterized in that: The preparation method of modified nanoparticles comprises the following steps: dispersing nano silicon dioxide and nano titanium dioxide in a mixture of anhydrous ethanol and deionized water respectively, performing ultrasonic treatment to obtain a silicon dioxide solution and a titanium dioxide solution respectively; dropping the silicon dioxide solution into the titanium dioxide solution while stirring, adjusting the pH value of the solution, stirring for reaction, obtaining core-shell composite particles, re-dispersing the core-shell structure particles in anhydrous ethanol, adding a silane coupling agent, stirring for reaction, obtaining silane-modified composite particles; dispersing the silane-modified composite particles in polyethyleneimine, stirring for reaction, obtaining modified nanoparticles.

9. The method for preparing a high-performance privacy film according to any one of claims 1 to 8, characterized in that: The steps include: A micro-concave roller with an anti-peeping unit and an anti-peeping structure 1 is engraved on a roller blank, and a chrome layer is formed on the surface of the micro-concave roller by chrome plating; an acrylic paint is applied to the upper surface of the substrate layer by hard pressure transfer using the micro-concave roller, and the anti-peeping structure layer 1 is obtained by curing; A micro-concave roller with a second anti-peeping structure is engraved on a roller blank, and a chrome layer is formed on the surface of the micro-concave roller by chrome plating; an acrylic paint is applied to the lower surface of the substrate layer by hard pressure transfer using the micro-concave roller, and cured to obtain the second anti-peeping structure layer; Applying black glue to the first anti-peeping structure and the first anti-peeping structure in the groove, and curing to obtain a first black glue layer; Black glue is applied to both sides of the second anti-peeping structure and solidified to obtain a second black glue layer.

10. The method for preparing a high-performance privacy film according to claim 9, characterized in that: The thickness of the chromium layer is 0.1-0.5μm. The black glue is cured under ultraviolet light, and the ultraviolet energy is 1000~1500mJ / cm 2 ; The preparation method also includes the following steps: coating white glue on black glue, and curing under ultraviolet light after coating, with the ultraviolet energy being 200-500mJ / cm 2 , get a white glue layer.

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