A privacy protection film and a method of manufacturing

Abstract

This invention relates to the field of composite film technology and discloses a privacy protective film and its preparation method. The privacy protective film of this invention is composed of a privacy film, a cured adhesive layer, and an anti-glare film. The cured adhesive layer includes 100 parts by weight of UV polyurethane, 0.6-1.2 parts by weight of silicone leveling agent, 36-45 parts by weight of reactive diluent, and 2.8-3.5 parts by weight of photoinitiator. The silicone leveling agent contains urethane bonds and polar carboxyl groups, which have good compatibility with UV polyurethane adhesive. At the same time, it enhances the bonding force between the adhesive and the anti-glare film and the privacy film, improves peel strength and adhesion performance. The polysiloxane molecular chains of the silicone leveling agent have low surface tension and can easily migrate to the adhesive interface, eliminating surface tension differences, homogenizing surface tension, promoting adhesive leveling and smooth spreading, and improving the smoothness of the privacy protective film.

Description

Technical Field

[0001] This invention relates to the field of composite film technology, specifically to a privacy protective film and its preparation method. Background Technology

[0002] Screen protectors, privacy and anti-glare films are frequently used on mobile phones, tablets, and other devices. Privacy and anti-glare films typically consist of a privacy film, an AG anti-glare film, and an adhesive. The adhesive mainly serves to bond the privacy film to the anti-glare film. Ordinary adhesives have poor leveling properties, making it difficult to spread evenly and form a smooth, uniform, and even adhesive layer. This affects the flatness of the privacy and anti-glare film, making it prone to deformation and peeling, thus reducing its aesthetics and privacy and anti-glare effects.

[0003] UV polyurethane has advantages such as light curing, solvent-free properties, and good adhesion. It usually requires the addition of leveling agents, such as modified silicone, acrylate copolymers, and fluorocarbon leveling agents. Among them, silicone leveling agents have low surface tension, good leveling and wetting properties, and excellent weather resistance and high temperature resistance, and are widely used. The present invention aims to add silicone leveling agents to UV polyurethane adhesives to improve the adhesive and leveling properties of the adhesives, so as to maintain good flatness of the privacy and anti-glare film. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a privacy screen protector and its preparation method, solving problems such as poor adhesive leveling and unevenness of the privacy screen protector.

[0005] The technical solution of the present invention is: a privacy protective film and a preparation method thereof, wherein the privacy protective film is composed of a privacy film, a cured adhesive layer and an anti-glare film.

[0006] The method for preparing the privacy screen protector is as follows: (1) Add 1,4-dioxane, water, glutamic acid and sodium hydroxide aqueous solution to the reaction vessel, stir, add 1,4-dioxane solution of allyl chloroformate in an ice-water bath, and add sodium hydroxide aqueous solution dropwise to carry out the reaction. Add sodium bisulfate aqueous solution dropwise in an ice-water bath, extract with ethyl acetate, separate, distill under reduced pressure and dry to obtain allyl glutamic acid formaldehyde.

[0007] (2) Add toluene, hydrogen-containing silicone oil, chloroplatinic acid-isopropanol solution and allyl glutamate to the reaction vessel, introduce nitrogen gas to carry out the addition reaction, extract with saturated sodium chloride solution, separate, distill under reduced pressure and dry to obtain organosilicon leveling agent.

[0008] (3) Add UV polyurethane, silicone leveling agent, reactive diluent and photoinitiator to the container, stir and mix to obtain adhesive, then apply the adhesive to the non-anti-glare side of the anti-glare film, pre-cur it, and then attach the privacy film to obtain a composite film; cut the composite film into the required shape with a mold, take two pieces of high light transmittance flat glass, place the cut composite film between the two pieces of glass and clamp it flat, then place it under UV light irradiation for light curing, and after shaping, remove the glass pieces to obtain the privacy protection film.

[0009] Preferably, in (1), an aqueous sodium hydroxide solution is added dropwise to maintain the pH of the reaction solution to 9-10.

[0010] Preferably, in (1), sodium bisulfate aqueous solution is added dropwise to adjust the pH to 3-4.

[0011] Preferably, the molar ratio of glutamic acid to allyl chloroformate in (1) is 1:(1.14-1.21).

[0012] Preferably, the reaction in (1) is carried out at 20-30℃ for 72-96h.

[0013] Preferably, in (2), the molar ratio of the Si-H bond of the hydrogen-containing silicone oil to allyl glutamate is 1:(0.4-1).

[0014] Preferably, in (2), the mass ratio of the Si-H bond of the hydrogen-containing silicone oil to chloroplatinic acid is 100: (0.0018-0.0024).

[0015] Preferably, the reaction temperature in (2) is 90-110℃ and the reaction time is 4-7h.

[0016] Preferably, the active diluent in (3) includes one or more of tripropylene glycol diacrylate and 1,6-hexanediol diacrylate.

[0017] Preferably, the photoinitiator in (3) includes photoinitiator TPO, photoinitiator Irgacure184, photoinitiator Darocure1173, and photoinitiator Omnirad651.

[0018] Preferably, the pre-curing temperature in (3) is 130-140℃ and the time is 2.5-3min.

[0019] Preferably, the photocuring time in (3) is 2-3 min.

[0020] Preferably, in (3), the amount of UV polyurethane is 100 parts by weight, the amount of silicone leveling agent is 0.6-1.2 parts by weight, the amount of reactive diluent is 36-45 parts by weight, and the amount of photoinitiator is 2.8-3.5 parts by weight.

[0021] Preferably, the thickness of the privacy film in (3) is 75-250 μm.

[0022] Preferably, the thickness of the cured adhesive layer in (3) is 0.04-0.2 mm.

[0023] Preferably, in (3), the thickness of the anti-glare film is 0.05-0.2 mm, and the haze is 2-8%. The beneficial technical effects of this invention are as follows: An adhesive is obtained by mixing a silicone leveling agent and an active diluent in UV polyurethane, and then bonding an anti-glare film and a privacy film together. UV curing yields a privacy protective film. The silicone leveling agent contains urethane bonds, which form hydrogen bonds with UV polyurethane, improving the interfacial properties between the silicone leveling agent and UV polyurethane while having minimal impact on the adhesive's bonding performance. Simultaneously, the silicone leveling agent contains polar carboxyl groups, which can improve the cohesive force of the UV polyurethane adhesive, enhancing the bonding force between the adhesive and the anti-glare and privacy films, thereby improving peel strength and adhesion performance. Furthermore, the introduction of high-temperature resistant polysiloxane improves the heat aging resistance of the UV polyurethane adhesive, preventing deformation of the adhesive during prolonged use or at high temperatures, which could lead to problems such as peeling of the privacy protective film.

[0024] The polysiloxane molecular chains of the organosilicon leveling agent of the present invention have low surface tension, which makes them easy to migrate to the adhesive interface, eliminate surface tension difference, homogenize surface tension, promote adhesive leveling and smooth spreading, and improve the smoothness of privacy protection film. Detailed Implementation

[0025] To better explain the present invention, the main contents of the present invention are further illustrated below with reference to specific embodiments, but the contents of the present invention are not limited to the following embodiments.

[0026] The following UV polyurethane film, model 6112-100, is from Xiamen Aikema Chemical Co., Ltd. The anti-glare film is AG anti-glare film from Dongguan HengHua Optical Products Co., Ltd. The privacy film is PET type privacy film from Dongguan Xinglida Electronic Materials Co., Ltd.

[0027] Example 1: (1) Add 8 mL of 1,4-dioxane, 4 mL of water, 4 mmol of L-glutamic acid, and 4 mL of 2 mmol / mL sodium hydroxide aqueous solution to the reaction vessel. After stirring, add 2 nL of 1,4-dioxane solution containing 4.84 mmol of allyl chloroformate in an ice-water bath, and add 2 mmol / mL sodium hydroxide aqueous solution dropwise to maintain the pH of the reaction solution to 10. Stir the reaction at 20℃ for 96 h. Add 1 mmol / mL sodium bisulfate aqueous solution dropwise in an ice-water bath to adjust the pH to 3. Extract with ethyl acetate, separate, and then distill under reduced pressure and dry to obtain allyl glutamic acid carbamate. The reaction formula is as follows: .

[0028] (2) Add 10 mL of toluene, 10 g of hydrogen-containing silicone oil, 1 mL of isopropanol solution containing 18 mg of chloroplatinic acid, and allyl glutamate to the reaction vessel. Control the molar ratio of Si-H bond of hydrogen-containing silicone oil to allyl glutamate to be 1:0.6. Purge with nitrogen, heat to 100 °C, and stir to carry out olefin-silicone hydroaddition reaction for 4 h. During the reaction, reflux the solution and extract with saturated sodium chloride solution. After separation, distill the organic layer under reduced pressure and dry to obtain organosilicon leveling agent.

[0029] (3) Add 2kg UV polyurethane, 12g silicone leveling agent, 880g tripropylene glycol diacrylate and 63g photoinitiator Darocure1173 to the container, stir and mix to obtain an adhesive, then apply the adhesive to the non-anti-glare side of the anti-glare film, pre-cur at 140℃ for 2.5min, then attach the privacy film to obtain a composite film; cut the composite film into the required shape with a mold, take two pieces of high-transmittance flat glass, place the cut composite film between the two pieces of glass and clamp it flat, then place it under UV light irradiation for 2min for light curing, and remove the glass pieces after shaping to obtain a privacy protective film.

[0030] Example 2: (1) Add 8 mL of 1,4-dioxane, 4 mL of water, 4 mmol of L-glutamic acid, and 4 mL of sodium hydroxide aqueous solution with a concentration of 2 mmol / mL to the reaction vessel. After stirring, add 2 nL of 1,4-dioxane solution containing 4.56 mmol of allyl chloroformate in an ice-water bath, and add sodium hydroxide aqueous solution with a concentration of 2 mmol / mL to maintain the pH of the reaction solution to 9. Stir the reaction at 25°C for 96 h. Add sodium bisulfate aqueous solution with a concentration of 1 mmol / mL in an ice-water bath to adjust the pH to 3. Extract with ethyl acetate, separate, and then distill under reduced pressure and dry to obtain allyl glutamic acid carbamate.

[0031] (2) Add 15 mL of toluene, 10 g of hydrogen-containing silicone oil, 1.2 mL of isopropanol solution containing 24 mg of chloroplatinic acid, and allyl glutamate to the reaction vessel, and control the molar ratio of Si-H bond of hydrogen-containing silicone oil to allyl glutamate to be 1:1; introduce nitrogen gas, heat to 100 °C, stir and react for 7 h, reflux during the reaction, extract with saturated sodium chloride solution, separate, distill under reduced pressure and dry to obtain organosilicon leveling agent.

[0032] (3) Add 2kg UV polyurethane, 15g silicone leveling agent, 870g tripropylene glycol diacrylate and 70g photoinitiator TPO to the container, stir and mix to obtain an adhesive, then apply the adhesive to the non-anti-glare side of the anti-glare film, pre-cur at 130℃ for 3min, then attach the privacy film to obtain a composite film; cut the composite film into the required shape with a mold, take two pieces of high-transmittance flat glass, place the cut composite film between the two pieces of glass and clamp it flat, then place it under UV light irradiation for 2min for light curing, and remove the glass after shaping to obtain the privacy protection film.

[0033] Example 3: (1) Add 8 mL of 1,4-dioxane, 4 mL of water, 4 mmol of L-glutamic acid, and 4 mL of sodium hydroxide aqueous solution with a concentration of 2 mmol / mL to the reaction vessel. After stirring, add 2 nL of 1,4-dioxane solution containing 4.84 mmol of allyl chloroformate in an ice-water bath, and add sodium hydroxide aqueous solution with a concentration of 2 mmol / mL to maintain the pH of the reaction solution to 9. Stir the reaction at 20°C for 96 h. Add sodium bisulfate aqueous solution with a concentration of 1 mmol / mL in an ice-water bath to adjust the pH to 4. Extract with ethyl acetate, separate, and then distill under reduced pressure and dry to obtain allyl glutamic acid carbamate.

[0034] (2) Add 10 mL of toluene, 10 g of hydrogen-containing silicone oil, 1 mL of isopropanol solution containing 18 mg of chloroplatinic acid, and allyl glutamate to the reaction vessel, and control the molar ratio of Si-H bond of hydrogen-containing silicone oil to allyl glutamate to be 1:0.4; introduce nitrogen gas, heat to 110 °C, stir and react for 4 h, reflux during the reaction, extract with saturated sodium chloride solution, separate, distill under reduced pressure and dry to obtain organosilicon leveling agent.

[0035] (3) Add 2kg UV polyurethane, 18g silicone leveling agent, 900g tripropylene glycol diacrylate and 56g photoinitiator Darocure184 to the container, stir and mix to obtain an adhesive, then apply the adhesive to the non-anti-glare side of the anti-glare film, pre-cur at 140℃ for 2.5min, then attach the privacy film to obtain a composite film; cut the composite film into the required shape with a mold, take two pieces of high-transmittance flat glass, place the cut composite film between the two pieces of glass and clamp it flat, then place it under UV light irradiation for 2min for light curing, and remove the glass pieces after shaping to obtain a privacy protective film.

[0036] Example 4: (1) Add 8 mL of 1,4-dioxane, 4 mL of water, 4 mmol of L-glutamic acid, and 4 mL of sodium hydroxide aqueous solution with a concentration of 2 mmol / mL to the reaction vessel. After stirring, add 2 nL of 1,4-dioxane solution containing 4.56 mmol of allyl chloroformate in an ice-water bath, and add sodium hydroxide aqueous solution with a concentration of 2 mmol / mL to maintain the pH of the reaction solution to 10. Stir the reaction at 30°C for 72 h. Add sodium bisulfate aqueous solution with a concentration of 1 mmol / mL in an ice-water bath to adjust the pH to 4. Extract with ethyl acetate, separate, and then distill the organic layer under reduced pressure and dry to obtain allyl glutamic acid carbamate.

[0037] (2) Add 12 mL of toluene, 10 g of hydrogen-containing silicone oil, 1 mL of isopropanol solution containing 22 mg of chloroplatinic acid, and allyl glutamate to the reaction vessel, and control the molar ratio of Si-H bond of hydrogen-containing silicone oil to allyl glutamate to be 1:0.8; introduce nitrogen gas, heat to 90 °C, stir and react for 7 h, reflux during the reaction, extract with saturated sodium chloride solution, separate, distill under reduced pressure and dry to obtain organosilicon leveling agent.

[0038] (3) Add 2kg UV polyurethane, 20g silicone leveling agent, 760g 1,6-hexanediol diacrylate and 62g photoinitiator Darocure1173 to the container, stir and mix to obtain an adhesive, then apply the adhesive to the non-anti-glare side of the anti-glare film, pre-cur at 130℃ for 3min, then attach the privacy film to obtain a composite film; cut the composite film into the required shape with a mold, take two pieces of high-transmittance flat glass, place the cut composite film between the two pieces of glass and clamp it flat, then place it under UV light for 2min for light curing, and remove the glass after shaping to obtain the privacy protection film.

[0039] Comparative Example 1 differs from Example 1 in that no silicone leveling agent is added.

[0040] (1) Add 2kg UV polyurethane, 880g tripropylene glycol diacrylate and 63g photoinitiator Darocure1173 to the container, stir and mix to obtain an adhesive, then apply the adhesive to the non-anti-glare side of the anti-glare film, pre-cur at 140℃ for 2.5min, then attach the privacy film to obtain a composite film; cut the composite film into the required shape with a mold, take two pieces of high-transmittance flat glass, place the cut composite film between the two pieces of glass and clamp it flat, then place it under UV light irradiation for 2min for light curing, and remove the glass pieces after shaping to obtain the privacy protection film.

[0041] Comparative Example 2 differs from Example 1 in that it uses hydrogen-containing silicone oil instead of organosilicon leveling agent.

[0042] (1) Add 2kg UV polyurethane, 12g hydrogen-containing silicone oil, 880g tripropylene glycol diacrylate and 63g photoinitiator Darocure1173 to a container, stir and mix to obtain an adhesive, then apply the adhesive to the non-anti-glare side of the anti-glare film, pre-cur at 140℃ for 2.5min, then attach the privacy film to obtain a composite film; cut the composite film into the required shape using a mold, take two pieces of high-transmittance flat glass, place the cut composite film between the two pieces of glass and clamp it flat, then place it under UV light irradiation for 2min for light curing, and remove the glass pieces after shaping to obtain a privacy protective film.

[0043] Comparative Example 3 differs from Example 1 in that it uses acrylic acid instead of allyl glutamate.

[0044] (1) Add 10 mL of toluene, 10 g of hydrogen-containing silicone oil, 1 mL of isopropanol solution containing 18 mg of chloroplatinic acid, and acrylic acid to the reaction vessel. Control the molar ratio of Si-H bond of the hydrogen-containing silicone oil to allyl glutamate to be 1:0.6. Purge with nitrogen, heat to 100 °C, stir and react for 4 h. During the reaction, reflux the solution and extract with saturated sodium chloride solution. After separation, distill the organic layer under reduced pressure and dry to obtain the organosilicon leveling agent.

[0045] (2) Add 2kg UV polyurethane, 12g silicone leveling agent, 880g tripropylene glycol diacrylate and 63g photoinitiator Darocure1173 to the container, stir and mix to obtain an adhesive, then apply the adhesive to the non-anti-glare side of the anti-glare film, pre-cur at 140℃ for 2.5min, then attach the privacy film to obtain a composite film; cut the composite film into the required shape with a mold, take two pieces of high-transmittance flat glass, place the cut composite film between the two pieces of glass and clamp it flat, then place it under UV light irradiation for 2min for light curing, and remove the glass after shaping to obtain the privacy protection film.

[0046] Comparative Example 4 differs from Example 1 in that β-alanine is used instead of glutamic acid.

[0047] (1) Add 8 mL of 1,4-dioxane, 4 mL of water, 4 mmol of β-alanine, and 4 mL of sodium hydroxide aqueous solution with a concentration of 2 mmol / mL to the reaction vessel. After stirring, add 2 nL of 1,4-dioxane solution containing 4.84 mmol of allyl chloroformate in an ice-water bath, and add sodium hydroxide aqueous solution with a concentration of 2 mmol / mL to maintain the pH of the reaction solution to 10. Stir the reaction at 20°C for 96 h. Add sodium bisulfate aqueous solution with a concentration of 1 mmol / mL in an ice-water bath to adjust the pH to 3. Extract with ethyl acetate, separate, and then distill the organic layer under reduced pressure and dry to obtain allyl alanine carbamate.

[0048] (2) Add 10 mL of toluene, 10 g of hydrogen-containing silicone oil, 1 mL of isopropanol solution containing 18 mg of chloroplatinic acid, and allyl glutamate to the reaction vessel, and control the molar ratio of Si-H bond of hydrogen-containing silicone oil to allyl glutamate to be 1:0.6; introduce nitrogen gas, heat to 100 °C, stir and react for 4 h, reflux during the reaction, extract with saturated sodium chloride solution, separate, distill under reduced pressure and dry to obtain organosilicon leveling agent.

[0049] (3) Add 2kg UV polyurethane, 12g silicone leveling agent, 880g tripropylene glycol diacrylate and 63g photoinitiator Darocure1173 to the container, stir and mix to obtain an adhesive, then apply the adhesive to the non-anti-glare side of the anti-glare film, pre-cur at 140℃ for 2.5min, then attach the privacy film to obtain a composite film; cut the composite film into the required shape with a mold, take two pieces of high-transmittance flat glass, place the cut composite film between the two pieces of glass and clamp it flat, then place it under UV light irradiation for 2min for light curing, and remove the glass pieces after shaping to obtain a privacy protective film.

[0050] According to GB / T 2791-1995 standard, the T-peel strength of the adhesive in the privacy protective film to the anti-glare film and the privacy film was tested.

[0051] Place the privacy film in a constant temperature chamber at 120℃ for 240 hours, then remove it and leave it at room temperature for 6 hours before testing the T-peel strength.

[0052] According to GB / T 33403-2016 standard, the leveling performance of the adhesive is tested at 25℃. The smaller the difference ΔH between the highest and lowest readings, the better the leveling performance.

[0053] Table 1 Performance Tests

[0054] Compared to Comparative Example 1, the adhesives in each embodiment incorporated a silicone leveling agent containing urethane bonds, which forms hydrogen bonds with UV polyurethane, improving the interfacial properties between the silicone leveling agent and UV polyurethane while having minimal impact on the adhesive's bonding performance. Simultaneously, the silicone leveling agent contains polar carboxyl groups, which can enhance the cohesive force of the UV polyurethane adhesive, strengthening the bond between the adhesive and the anti-glare and privacy films, thereby improving peel strength and adhesion performance. It also exhibits higher high-temperature T-peel strength and better heat aging resistance. The polysiloxane molecular chains of the silicone leveling agent have low surface tension, easily migrating to the adhesive interface, eliminating surface tension differences, homogenizing surface tension, promoting adhesive leveling and smooth spreading, and improving the smoothness of the privacy film.

[0055] The hydrogen-containing silicone oil in Comparative Example 2 does not contain urethane bonds or carboxyl groups, and the organosilicon leveling agent (acrylic grafted hydrogen-containing silicone oil) in Comparative Example 3 does not contain urethane bonds and has a low carboxyl content. Both have poor compatibility with UV polyurethane adhesives, which will affect the peel strength and bonding performance of the adhesives. Furthermore, the poor leveling performance of the adhesives will affect the flatness of the privacy protective film.

[0056] The silicone leveling agent (β-alanine-grafted hydrogen-containing silicone oil) in Comparative Example 4 had a lower carboxyl content and a lower peel strength of the adhesive.

[0057] The above embodiments are merely best examples and are not intended to limit the implementation of the present invention. In addition to the above embodiments, the present invention may have other embodiments. All technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A privacy screen protector, characterized in that, The privacy protection film consists of a privacy film, a cured adhesive layer, and an anti-glare film; The cured adhesive layer comprises 100 parts by weight of UV polyurethane, 0.6-1.2 parts by weight of silicone leveling agent, 36-45 parts by weight of reactive diluent, and 2.8-3.5 parts by weight of photoinitiator; The organosilicon leveling agent is prepared by the following method: toluene, hydrogen-containing silicone oil, chloroplatinic acid-isopropanol solution, and allyl glutamate are added to a reaction vessel, nitrogen gas is introduced, the reaction is carried out, the mixture is extracted with saturated sodium chloride solution, the organic layer is separated, the organic layer is distilled under reduced pressure and dried to obtain the organosilicon leveling agent.

2. The privacy protective film according to claim 1, characterized in that, The reactive diluent includes one or more of tripropylene glycol diacrylate and 1,6-hexanediol diacrylate; the photoinitiator includes one or more of photoinitiator TPO, photoinitiator Irgacure184, photoinitiator Darocure1173, and photoinitiator Omnirad651.

3. The privacy protective film according to claim 1, characterized in that, The molar ratio of the Si-H bond in the hydrogen-containing silicone oil to allyl glutamate is 1:(0.4-1).

4. The privacy protective film according to claim 1, characterized in that, The mass ratio of the Si-H bond in the hydrogen-containing silicone oil to chloroplatinic acid is 100:(0.0018-0.0024).

5. The privacy protective film according to claim 1, characterized in that, The reaction temperature is 90-110℃, and the reaction time is 4-7h.

6. The privacy protective film according to claim 1, characterized in that, The allyl glutamate was prepared by the following method: 1,4-dioxane, water, glutamic acid, and an aqueous sodium hydroxide solution were added to a reaction vessel. After stirring, a 1,4-dioxane solution of allyl chloroformate was added in an ice-water bath, and an aqueous sodium hydroxide solution was added dropwise to maintain the pH of the reaction solution to 9-10. The reaction was then stirred at 20-30°C for 72-96 hours. An aqueous sodium bisulfate solution was added dropwise in an ice-water bath to adjust the pH to 3-4. The mixture was extracted with ethyl acetate, and after separation, the organic layer was distilled under reduced pressure and dried to obtain allyl glutamate.

7. The privacy protective film according to claim 6, characterized in that, The molar ratio of glutamic acid to allyl chloroformate is 1:(1.14-1.21).

8. A method for preparing a privacy protective film as described in any one of claims 1-7, characterized in that, The preparation method is as follows: UV polyurethane, silicone leveling agent, reactive diluent, and photoinitiator are added to a container and stirred to obtain an adhesive. The adhesive is then applied to the non-anti-glare side of the anti-glare film and pre-cured. The privacy film is then laminated to obtain a composite film. The composite film is cut into the required shape using a mold. Two flat glass sheets with high light transmittance are taken, and the cut composite film is placed between the two glass sheets and clamped flat. It is then placed under UV light for photocuring. After shaping, the glass sheets are removed to obtain the privacy protective film.

9. The method for preparing the privacy protective film according to claim 8, characterized in that, The pre-curing temperature is 130-140℃ and the time is 2.5-3 minutes.

10. The method for preparing the privacy protective film according to claim 8, characterized in that, The photocuring time is 2-3 minutes.

Images