Display screen protective film with high blue light barrier property and preparation process thereof

Abstract

The invention discloses a display screen protective film with high blue light barrier property and a preparation process thereof, and belongs to the technical field of display screen protective films. The display screen protective film with the blue light high barrier property comprises a buffer frame and a film body, the buffer frame and the film body are integrally formed through hot pressing, the buffer frame is made of modified ethylene propylene diene monomer rubber materials, a U-shaped groove is formed in the buffer frame and used for being clamped with a display screen, and the film body comprises a base material layer, a blue light barrier layer and a functional coating which are sequentially connected. According to the display screen protective film with the blue light high barrier property and the preparation process thereof, a mode of combining an organic blue light absorbing material and an inorganic blue light reflecting layer is adopted in the design of the blue light barrier layer, so that efficient blue light filtering is realized; and the buffer rack made of a modified ethylene propylene diene monomer material provides excellent impact absorption capacity for the display screen.

Description

Technical Field

[0001] The present invention relates to the technical field of display screen protective films, and particularly to a display screen protective film with high blue light barrier property and its preparation process. Background Art

[0002] With the popularization of electronic devices, the usage time of display screens has increased significantly. Prolonged exposure to blue light may cause eye fatigue, retinal damage, and even sleep disorders. Currently, most blue light protective films on the market use single-layer organic dyes for absorption or simple coating technology, which have problems such as low barrier efficiency, insufficient mechanical strength, and easy yellowing. In addition, the traditional way of fixing the protective film to the display screen is mostly by gluing, which cannot be disassembled, is not flexible enough to use, and lacks a buffer structure, resulting in poor impact resistance. Summary of the Invention

[0003] The purpose of the present invention is to provide a display screen protective film with high blue light barrier property and its preparation process. By adopting a combination of organic blue light absorbing materials and inorganic blue light reflecting layers in the design of the blue light barrier layer, efficient blue light filtration is achieved, improving the durability and reliability of the product, and solving the problems raised in the above background art.

[0004] To achieve the above purpose, the present invention provides the following technical solution: A display screen protective film with high blue light barrier property, including a buffer frame and a film body. The buffer frame and the film body are integrally formed by hot pressing. The buffer frame is made of modified ethylene propylene diene monomer (EPDM) rubber material. A U-shaped groove is opened on the buffer frame, and the U-shaped groove is used for clamping with the display screen. The film body is installed on the surface of the display screen through the buffer frame to protect the display screen. The film body includes a substrate layer, a blue light barrier layer, and a functional coating connected in sequence.

[0005] Preferably, the preparation method of the modified ethylene propylene diene monomer (EPDM) rubber is as follows: First, put the ethylene propylene diene monomer (EPDM) rubber into a mixer with a temperature of 80 - 100°C and a rotation speed of 30 - 50 rpm, and slowly add short-cut carbon fibers to prevent agglomeration. Then, add paraffin oil and an oxidant in sequence, and mix for 8 - 10 minutes until the carbon fibers are evenly dispersed. Control the temperature of the open mill at 60°C, add peroxide vulcanizing agent DCP and co-crosslinking agent TAIC, and thin pass 3 - 4 times to ensure uniformity and then take out the sheet.

[0006] Preferably, the modified ethylene propylene diene monomer (EPDM) rubber comprises the following raw materials in parts by weight:

[0007] 90 - 110 parts of ethylene propylene diene monomer (EPDM) rubber, 6 - 10 parts of short-cut carbon fibers, 2 - 4 parts of dicumyl peroxide, 1 - 2 parts of TAIC, 4 - 7 parts of zinc oxide, and 12 - 18 parts of paraffin oil. Among them, the ethylene content of the ethylene propylene diene monomer (EPDM) rubber is not less than 60%, the molecular chain has high flexibility, and the rebound rate can reach more than 85%.

[0008] Preferably, the preparation method of the buffer rack is as follows:

[0009] Preheat the mold to 160 - 180 °C, inject the modified ethylene propylene diene monomer (EPDM) rubber with an injection pressure of 80 - 100 Mpa, use medium and low speeds to prevent fiber sedimentation, hold the pressure for 30 seconds, cool for 60 seconds, take out the formed EPDM part from the mold, cool it to room temperature, and wipe off the residual mold release agent on the surface with isopropyl alcohol.

[0010] Lay the EPDM part flat on a high-temperature resistant tray, put it into a vacuum vulcanizing tank, accurately control the temperature at 170 °C and time for 5 minutes. After the post-vulcanization is completed, immediately take out the part and let it cool slowly at room temperature to complete the post-vulcanization operation.

[0011] Conduct surface pretreatment on the EPDM part. First, perform plasma cleaning, then spray the EPDM part with a silane primer, bake it at 60 °C for 5 minutes after spraying. Dilute the fluorosilicone resin to a viscosity of 15 - 20 cP, use a spray gun with a nozzle diameter of 0.3 mm, and use an air pressure of 0.3 MPa to spray the surface film on the EPDM part. The film thickness is 5 - 10 μm, and bake it in an oven at 80 °C for 30 minutes to form a low-friction surface.

[0012] Preferably, the substrate layer is made of PET or TPU material. Both PET and TPU materials have high transparency, good mechanical strength, and strong impact resistance.

[0013] Preferably, the blue light blocking layer is composed of an organic blue light absorption layer and an inorganic blue light reflection layer. Among them, the organic blue light absorption layer is processed by the solution coating method using an organic blue light absorption material, and the inorganic blue light reflection layer is processed onto the surface of the organic blue light absorption layer by magnetron sputtering coating of inorganic nanoparticles.

[0014] Preferably, the preparation method of the blue light blocking layer is as follows:

[0015] Dissolve the organic blue light absorption material in a solvent, add an acrylic resin as a film-forming agent, use microgravure coating, the screen ruling is 200 - 300 lines / inch, the coating speed is 20 - 30 m / min, dry it with hot air at 80 - 100 °C for 1 - 2 minutes, and perform UV curing to enhance the adhesion. After drying, the film thickness of the organic blue light absorption layer is 1 - 3 μm.

[0016] Deposit two inorganic nanoparticle materials alternately, each layer has a thickness of 100 - 120 nm, and the total number of layers is 5 layers or 7 layers to form the inorganic blue light reflection layer.

[0017] Preferably, the functional coating includes at least an anti-glare layer and an anti-fingerprint layer. Silica microparticles are added to the anti-glare layer to reduce surface reflection, and a fluorosilane coating is provided on the anti-fingerprint layer to make it hydrophobic and oleophobic.

[0018] Preferably, the film body further includes an optical matching layer, which is made of nano-ZrO 2 doped acrylic resin to adjust the refractive index, reduce interface reflection, and improve the light transmittance.

[0019] Another technical problem to be solved by the present invention is to provide a preparation process for a display screen protection film with high blue light barrier performance, including the following steps:

[0020] Step 1: Inject the modified ethylene propylene diene monomer (EPDM) rubber material into a mold for molding, and through post-vulcanization and surface treatment processes, form a buffer rack with a U-shaped groove;

[0021] Step 2: Clean the surface of the substrate layer by plasma and set it aside;

[0022] Dissolve the organic blue light absorbing material in a solvent, and through microgravure coating, form a uniform film after drying. Sputter inorganic nanoparticle materials onto the film in a vacuum environment to form a blue light barrier layer;

[0023] Spin-coat the material of the optical matching layer between the substrate layer and the blue light barrier layer, with a thickness of 50-100 nm, and cure at 80 °C for 10 minutes to connect the substrate layer and the blue light barrier layer;

[0024] Spray an anti-glare layer coating and an anti-fingerprint layer coating on the surface of the blue light barrier layer, perform laser cutting, match the screen size, and perform explosion-proof treatment on the edge;

[0025] Step 3: Embed the edge of the film body into the U-shaped groove of the buffer rack, and use optical clear adhesive (OCA) for hot pressing and laminating at a temperature of 70 °C, a pressure of 0.5 MPa, and a time of 10 seconds.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] The display screen protection film with high blue light barrier performance and its preparation process provided by the present invention not only adopt a combination of an organic blue light absorbing material and an inorganic blue light reflecting layer in the design of the blue light barrier layer to achieve efficient blue light filtering, but also provide excellent shock absorption ability for the display screen through a buffer rack made of modified EPDM rubber material. In addition, the anti-glare layer and anti-fingerprint layer in the functional coating further improve the user experience, while the optical matching layer effectively reduces interface reflection and improves the light transmittance. The overall structure is formed by hot pressing in one body, ensuring the tight combination between layers and improving the durability and reliability of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is the overall structure diagram of the display screen protection film with high blue light barrier performance of the present invention;

[0029] Figure 2 It is the cross-sectional view of the film body of the present invention.

[0030] In the figure: 1. Buffer rack; 11. U-shaped groove; 2. Film body; 21. Substrate layer; 22. Blue light blocking layer; 221. Organic blue light absorbing layer; 222. Inorganic blue light reflecting layer; 23. Functional coating; 231. Anti-glare layer; 232. Anti-fingerprint layer; 24. Optical matching layer. Specific implementation mode

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0032] Embodiment 1:

[0033] Please refer to Figure 1 - Figure 2 , take 100 parts of ethylene propylene diene monomer rubber, 8 parts of carbon fiber, 3 parts of DCP, 1.5 parts of TAIC, 5 parts of zinc oxide, and 15 parts of paraffin oil by weight,

[0034] First, put the ethylene propylene diene monomer rubber into a mixer with a temperature of 80 °C and a rotation speed of 50 rpm, and slowly add chopped carbon fiber to prevent agglomeration. Then, add paraffin oil and oxidant in sequence, mix for 8 minutes until the carbon fiber is evenly dispersed. Control the temperature of the open mill at 60 °C, add DCP and TAIC, and thin pass 3-4 times to ensure uniformity and then take out the sheet.

[0035] Preheat the mold to 160-180 °C, inject the modified ethylene propylene diene monomer rubber with an injection pressure of 100 Mpa, adopt medium and low speed to prevent fiber sedimentation, keep the pressure for 30 seconds, cool for 60 seconds, take out the formed EPDM part from the mold, cool it to room temperature, and wipe the surface with isopropyl alcohol to remove the residual mold release agent;

[0036] Lay the EPDM part flat on a high-temperature resistant tray, put it into a vacuum vulcanizing tank, accurately control the temperature at 170 °C and time for 5 minutes. After the post-vulcanization is completed, immediately take out the part and place it at room temperature to cool slowly to complete the post-vulcanization operation.

[0037] Perform surface pretreatment on the EPDM part. First, perform plasma cleaning, then spray the EPDM part with a silane primer, bake it at 60 °C for 5 minutes. Dilute the fluorosilicone resin to a viscosity of 15-20 cP, use a spray gun with a caliber of 0.3 mm, use an air pressure of 0.3 MPa, spray the surface film on the EPDM part, with a film thickness of 5-10 μm, and bake it in an oven at 80 °C for 30 minutes to form a low-friction surface, and make the buffer rack 1.

[0038] Select 0.2 mm PET as the substrate layer 21 with a light transmittance of 93%. For the organic blue light absorption layer 221, select 8 wt% benzotriazole. Dissolve benzotriazole in acetone, add acrylic resin as a film-forming agent, and use microgravure coating with a coating speed of 30 m / min. Dry it with hot air at 80 °C for 1 - 2 minutes, and then perform UV curing to enhance adhesion. After drying, the film thickness of the organic blue light absorption layer 221 is 1 - 3 μm;

[0039] The inorganic blue light reflection layer 222 uses 7 layers of TiO 2 / SiO 2 , with a total thickness of 840 nm. Alternately deposit two inorganic nanoparticle materials on the organic blue light absorption layer 221, with each layer having a thickness of 100 - 120 nm and a total of 7 layers, forming the inorganic blue light reflection layer 222.

[0040] Spin - coat an acrylic resin doped with nano - ZrO 2 between the substrate layer 21 and the blue light barrier layer 22, with a thickness of 60 nm. Cure it at 80 °C for 10 minutes to connect the substrate layer 21 and the blue light barrier layer 22.

[0041] SiO 2 particles are mixed with acrylic resin and sprayed onto the surface of the blue light barrier layer 22 with a haze of 15%, forming an anti - glare layer 231. Perform UV curing, and spray a fluorosilicone resin coating on the surface of the anti - glare layer 231 to form an anti - fingerprint layer 232.

[0042] Embed the edge of the film body 2 into the U - shaped groove 11 of the buffer frame 1, and use OCA optical adhesive for hot - press lamination at a temperature of 70 °C, a pressure of 0.5 MPa, and a time of 10 seconds to make a display screen protective film with high blue light barrier performance.

[0043] Example Two:

[0044] Take 110 parts by weight of ethylene - propylene - diene monomer rubber, with an ethylene content of 65%, 10 parts of carbon fiber, 3 parts of DCP, 1.5 parts of TAIC, 5 parts of zinc oxide, and 15 parts of paraffin oil. Modify the ethylene - propylene - diene monomer rubber using the same method as in Example One to prepare the buffer frame 1. The substrate layer 21 uses 0.3 mm TPU, and the inorganic blue light reflection layer 222 of the blue light barrier layer 22 is 5 layers of CeO 2 / SiO 2 , with each layer being 110 nm and containing 0.1 wt% graphene. The other materials are the same as in Example One, and use the method of Example One to process a display screen protective film with high blue light barrier performance.

[0045] Example Three:

[0046] Take 95 parts of ethylene propylene diene monomer rubber, 10 parts of carbon fiber, 3 parts of DCP, 1.5 parts of TAIC, 5 parts of zinc oxide, and 15 parts of paraffin oil by weight. Modify the ethylene propylene diene monomer rubber using the same method as in Example 1 to prepare Buffer Frame 1. The substrate layer 21 uses 0.15 mm PET. For the organic blue light absorption layer 221 of the blue light barrier layer 22, 10 wt% benzotriazole is selected. The inorganic blue light reflection layer 222 uses 7 layers of Nb 2 O 5 / SiO 2 , and antibacterial silver ions are added to the anti-glare layer 231 with a haze of 10%. Other materials are the same as in Example 1, and the method of Example is used to process a display screen protective film with high blue light barrier performance.

[0047] Comparative Example 1:

[0048] In this comparative example, the blue light barrier layer 22 is a 3 μm organic blue light absorption layer 221. The inorganic blue light reflection layer 222 is omitted in this comparative example, and other structures are the same as in Example 1.

[0049] Comparative Example 2:

[0050] In this comparative example, the structure of Buffer Frame 1 is omitted, and ordinary OCA glue is directly bonded to the film body 2, and other structures are the same as in Example 1.

[0051] Perform performance tests on the display screen protective films with high blue light barrier performance prepared in the above examples and comparative examples to obtain the following data:

[0052]

[0053]

[0054] Through the organic absorption + inorganic reflection multi-layer structure in the example, the blue light barrier rate is > 89% in all cases, which is significantly better than the single-layer organic film in Comparative Example 1. The lack of a buffer frame in Comparative Example 2 results in poor mechanical properties. The modified EPDM buffer frame + TPU / PET substrate combination in the example shows excellent performance in the falling ball impact test, while Comparative Example 2 is prone to cracking. In Example 3, due to the addition of fluorosilicone resin and antibacterial layer, ΔYI is only 0.8 and the wear resistance is the best.

[0055] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device.

[0056] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A display screen protective film with high blue light blocking performance, comprising a buffer frame (1) and a film body (2), characterized in that: The buffer frame (1) and the membrane body (2) are integrally formed by hot pressing. The buffer frame (1) is made of modified EPDM rubber material. A U-shaped groove (11) is provided on the buffer frame (1). The U-shaped groove (11) is used to engage with a display screen. The membrane body (2) comprises a substrate layer (21), a blue light blocking layer (22) and a functional coating (23) which are connected in sequence.

2. The display screen protective film with high blue light blocking property according to claim 1, characterized in that: The preparation method of the modified EPDM rubber is as follows: first, the EPDM rubber is put into an internal mixer at a temperature of 80-100° C. and a rotation speed of 30-50 rpm, and short-cut carbon fibers are slowly added to prevent agglomeration, and paraffin oil and an oxidant are added in sequence, mixed for 8-10 minutes until the carbon fibers are evenly dispersed, the temperature of the open mixer is controlled at 60° C., peroxide curing agent DCP and auxiliary cross-linking agent TAIC are added, and thin-passed 3-4 times to ensure uniformity before discharging the sheet.

3. The display screen protective film with high blue light blocking property according to claim 2, characterized in that: The modified EPDM rubber comprises the following raw materials in parts by weight: 90-110 parts of EPDM rubber, 6-10 parts of chopped carbon fibers, 2-4 parts of dicumyl peroxide, 1-2 parts of TAIC, 4-7 parts of zinc oxide and 12-18 parts of paraffin oil, wherein the ethylene content of the EPDM rubber is not less than 60%.

4. The display screen protective film with high blue light blocking property according to claim 1, characterized in that: The preparation method of the buffer frame (1) is as follows: Preheat the mold to 160-180℃, inject the modified EPDM rubber at an injection pressure of 80-100Mpa, hold the pressure for 30 seconds, cool for 60 seconds, remove the molded EPDM parts from the mold, cool to room temperature, and wipe with isopropyl alcohol to remove the surface release agent residue; Lay the EPDM parts flat on a high temperature resistant tray and put them into a vacuum vulcanization tank. Accurately control the temperature at 170°C and the timing for 5 minutes. After the post-vulcanization is completed, take out the parts immediately and place them at room temperature to slowly cool down. After the vulcanization operation is completed, The surface of the EPDM parts was pretreated by plasma cleaning, and then the EPDM parts were sprayed with silane primer. After spraying, they were baked at 60°C for 5 minutes. The fluorosilicone resin was diluted to a viscosity of 15-20cP. A spray gun with a diameter of 0.3mm and an air pressure of 0.3MPa were used to spray the surface film on the EPDM parts. The film thickness was 5-10μm. The film was baked in an oven at 80°C for 30 minutes to form a low-friction surface.

5. The display screen protective film with high blue light blocking property according to claim 1, characterized in that: The substrate layer (21) is made of PET or TPU material.

6. The display screen protective film with high blue light blocking property according to claim 1, characterized in that: The blue light blocking layer (22) comprises an organic blue light absorbing layer (221) and an inorganic blue light reflecting layer (222), wherein the organic blue light absorbing layer (221) is an organic blue light absorbing material processed by a solution coating method, and the inorganic blue light reflecting layer (222) is inorganic nanoparticles processed onto the surface of the organic blue light absorbing layer (221) by magnetron sputtering coating.

7. The display screen protective film with high blue light blocking property according to claim 6, characterized in that: The preparation method of the blue light blocking layer (22) is as follows: The organic blue light absorbing material is dissolved in a solvent, an acrylic resin is added as a film-forming agent, and micro-gravure coating is adopted, the screen number is 200-300 lines / inch, the coating speed is 20-30m / min, hot air drying is performed at 80-100°C for 1-2 minutes, UV curing is performed to enhance adhesion, and the film thickness of the organic blue light absorbing layer (221) after drying is 1-3μm; Two inorganic nanoparticle materials are alternately deposited, each layer having a thickness of 100-120 nm, and a total number of layers of 5 or 7 layers, to form an inorganic blue light reflecting layer (222).

8. The display screen protective film with high blue light blocking property according to claim 1, characterized in that: The functional coating (23) comprises at least an anti-glare layer (231) and an anti-fingerprint layer (232); silicon dioxide particles are added to the anti-glare layer (231); and the anti-fingerprint layer (232) is provided with a fluorosilane coating and is hydrophobic and oleophobic.

9. The display screen protective film with high blue light blocking property according to claim 1, characterized in that: The film body (2) further comprises an optical matching layer (24), and the optical matching layer (24) is made of nano ZrO2 doped with acrylic resin.

10. A process for preparing a display screen protective film with high blue light blocking properties as claimed in claim 9, characterized in that: The following steps are involved: Step 1: injecting a modified EPDM rubber material into a mold for molding, and performing post-vulcanization and surface treatment processes to form a buffer frame (1) with a U-shaped groove (11); Step 2: plasma cleaning the surface of the substrate layer (21) for later use; Dissolving an organic blue light absorbing material in a solvent, applying the material by micro-gravure coating, drying the material to form a uniform film, and sputtering an inorganic nanoparticle material onto the film in a vacuum environment to form a blue light blocking layer (22); Spin-coating the material of the optical matching layer (24) between the substrate layer (21) and the blue light blocking layer (22) to a thickness of 50-100 nm, and curing at 80° C. for 10 minutes to connect the substrate layer (21) and the blue light blocking layer (22); Spraying an anti-glare layer (231) and an anti-fingerprint layer (232) on the surface of the blue light blocking layer (22), laser cutting to match the screen size, and performing explosion-proof treatment on the edges; Step 3: embed the edge of the membrane body (2) into the U-shaped groove (11) of the buffer frame (1), and use optical adhesive OCA for hot pressing at a temperature of 70°C, a pressure of 0.5 MPa, and a time of 10 seconds.

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