A pet protective film and a method for manufacturing the same

Abstract

The application discloses a PET protective film and a preparation method thereof, and relates to the technical field of polymer films. The PET protective film comprises a film base material, a grid layer and a release layer. The grid layer is formed by coating a photocuring adhesive on one side of the film base material by a grid roller, and then being formed by being pressed and being cured by ultraviolet light. The release layer is formed by coating a release silicone oil on the surface of the grid layer. Specifically, the photocuring adhesive is composed of a photocuring resin, an active diluent, a photoinitiator and other additives. The photocuring resin is specifically a combination of isocyanate-terminated polyurethane prepolymer, methyl hydroxy acrylate and an allyl-terminated epoxy polyether. The release silicone oil is at least one of acrylate polysiloxane and hyperbranched polysiloxane. According to the above scheme, the prepared PET protective film not only has good release effect, but also can maintain high residual adhesion rate after being used for many times, and has excellent exhaust effect.

Description

Technical Field

[0001] This invention relates to the technical field of polymer films, and in particular to a PET protective film and its preparation method. Background Technology

[0002] During the production, processing, inspection, and transportation of electronic LCD displays or some optical components, external contaminants can cause pollution and damage to these components. In practical applications, a release liner is applied to the surface of these components to achieve a certain level of protection. To better protect the products, the release liner must meet the protection requirements of various products. For example, for large-area screen components such as electronic LCD displays and OLED screens, the protective film must not only have long-term stable light release adhesion properties—neither too sticky nor completely lacking in adhesion—but also support repeated application and use during continuous operation without generating air bubbles. Therefore, the requirements for the wettability, adhesion, and bubble removal properties of the release liner's bonding surface are very high.

[0003] However, the performance of release films currently on the market varies greatly. When bonded to screen components, they are prone to over-adhesion or easy detachment. Moreover, most are only suitable for single-use applications, often detaching due to weakened adhesion upon repeated application, failing to maintain reliable protection. Furthermore, they generally suffer from poor air venting, making it difficult to fully remove air between the screen and the film layer during bonding. This easily leads to the formation of air bubbles after application, affecting both appearance quality and interfering with subsequent processing and testing of screen components. Summary of the Invention

[0004] In order to overcome the shortcomings of existing release protective films, such as insufficient adhesion stability to screen components, difficulty in repeated application, and easy generation of air bubbles, this application provides a PET protective film and its preparation method.

[0005] Firstly, the PET protective film provided in this application adopts the following technical solution:

[0006] A PET protective film includes a film substrate and a mesh layer and a release layer sequentially coated on one side of the film substrate. The film substrate is a PET film. The mesh layer is formed by coating and imprinting a photocurable adhesive onto one side of the film substrate with an anilox roller and curing it by ultraviolet light. The release layer is formed by coating the surface of the mesh layer with release silicone oil.

[0007] The photocurable adhesive comprises the following raw materials in parts by weight:

[0008] UV-curable resin: 60-65 parts;

[0009] Reactive diluent: 25-30 parts;

[0010] Photoinitiator: 4-7.5 parts;

[0011] Organotin catalyst: 0.05-0.08 parts;

[0012] Acrylic leveling agent: 0.3-0.8 parts;

[0013] The photocurable resin is a composition of isocyanate-terminated polyurethane prepolymer, methhydroxy acrylate, and terminal allyl epoxy polyether, wherein the mass ratio of the isocyanate-terminated polyurethane prepolymer, methhydroxy acrylate, and terminal allyl epoxy polyether is 5:(2-4):(1-3).

[0014] The release silicone oil is at least one of acrylate polysiloxane and hyperbranched polysiloxane.

[0015] By adopting the above technical solution, a composition of isocyanate-terminated polyurethane prepolymer, methyl hydroxy acrylate, and terminally allyl epoxy polyether is used as the main photocurable resin. Combined with other additives, the photocurable adhesive can simultaneously undergo free radical polymerization and cationic ring-opening polymerization, thus forming a rigid-flexible balanced cross-linked network, which helps ensure the adhesion and long-term fatigue resistance of the mesh layer. Secondly, the release layer formed by release silicone oil not only appropriately reduces the adhesion of the mesh layer, enabling the PET protective film to achieve a "light release" effect, but also fully integrates with the mesh layer, achieving low surface migration and ensuring that the PET protective film still has a high residual adhesion rate after multiple uses. Furthermore, the mesh structure of the mesh layer not only structurally reduces the release contact area of ​​the PET protective film, achieving further control of the release force, but the spacing between the meshes also provides air venting channels, giving the PET protective film superior venting performance during lamination. By combining raw materials and structural features, it is possible to produce PET protective films that have good light release properties, maintain a high residual adhesion rate after multiple uses, and have excellent venting effects.

[0016] Optionally, in the photocurable adhesive, the reactive diluent is at least one of tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, and isodecyl acrylate; and the photoinitiator is at least one of photoinitiator 1173 or photoinitiator IRGACURE 250.

[0017] Optionally, the method for preparing the photocurable adhesive includes the following steps:

[0018] Under light-protected conditions, the photocurable resin, reactive diluent, and organotin catalyst are thoroughly mixed and heated to 75-83°C. The mixture is stirred thoroughly for 3-4 hours, then the temperature is lowered to 40-55°C. A photoinitiator and acrylate leveling agent are added, and the mixture is stirred for 1-3 minutes while maintaining the temperature. After cooling, the photocurable adhesive is obtained and stored under light-protected conditions for later use.

[0019] By adopting the above technical solution, the preparation method is simple and convenient, and only basic heating and stirring equipment is needed to complete the preparation of the light-curing adhesive.

[0020] Optionally, the mesh layer (2) is composed of recessed textures and raised grids, wherein the width of the raised grids is 160-180μm, the width of the recessed textures is 20-30μm, and the depth of the recessed textures is 2-10μm.

[0021] By adopting the above technical solution, when the direction of the recessed texture is at a 45° angle to the edge of the film substrate and a conventional bonding method is used, the recessed texture formed between the grids directly points to and leads to the edge of the film. This provides a continuous, short, straight, and least-resistance escape channel for internal air during bonding, guiding the air between the PET protective film and the bonded surface to escape from multiple directions during the bonding process. This improves the air venting performance of the PET protective film and effectively prevents air bubble residue. Furthermore, by controlling the width of the raised grids and the depth of the recessed textures, the air venting effect of the grid layer can also be effectively ensured. Combined with the arrangement direction of the recessed textures, this further improves the air venting performance of the PET protective film.

[0022] Optionally, the release silicone oil is specifically a composition of acrylate polysiloxane and hyperbranched polysiloxane, and the mass ratio of the acrylate polysiloxane to the hyperbranched polysiloxane is 1:(0.6-1).

[0023] By adopting the above technical solution, the difference between release force and residual adhesion rate when using acrylate polysiloxane or hyperbranched polysiloxane as release silicone oil alone can be effectively balanced. This is beneficial for PET protective film to have a light release effect and excellent residual adhesion rate, and improves the overall release adhesion performance of PET protective film.

[0024] Optionally, the surface tension of the release layer is 52-56 dynes.

[0025] By adopting the above technical solution, it is beneficial for the PET protective film to fully bond with the surface of the screen element, which helps to improve the bonding stability when used as a screen element.

[0026] Optionally, the side of the thin film substrate facing away from the mesh layer is further provided with an anti-scratch layer and an anti-static layer;

[0027] The anti-scratch layer is formed by coating a three-proof adhesive onto the side of the film substrate away from the mesh layer and then curing it, and the anti-scratch layer has a frosted matte structure.

[0028] The antistatic layer is formed by uniformly atomizing antistatic spray onto the surface of the scratch-resistant layer and then drying and curing it.

[0029] By adopting the above technical solutions, the scratch-resistant layer not only improves the surface scratch resistance of the PET protective film and provides long-lasting protection, but also the frosted texture makes it easier for users to distinguish the front and back of the PET protective film. Secondly, the anti-static layer formed by anti-static spraying can quickly eliminate the static charge on the surface of the PET protective film, helping to prevent dust from being attracted by static electricity on the PET protective film surface, while also solving the problems of dust contamination and component damage caused by static electricity.

[0030] Secondly, the method for preparing a PET protective film provided in this application adopts the following technical solution:

[0031] A method for preparing a PET protective film includes the following steps:

[0032] S1. First, using an anilox roller coating method, a light-curing adhesive is applied to one side of the film substrate in a light-protected state. At the same time, the other side of the film substrate is irradiated with ultraviolet light for the first time to form a grid layer. Then, using a matte roller coating method, a three-proof coating adhesive is applied to the side of the film substrate away from the grid layer in a light-protected state. After the coating is completed, both sides of the film substrate are irradiated with ultraviolet light for the second time to form a scratch-resistant layer. The grid layer is then fully cured and wound up to obtain the first intermediate film.

[0033] S2. Using a coating roller, release silicone oil is coated on the surface of the mesh layer in a light-proof state. Then, it is pre-baked in an oven at 60-70℃ for 3-5 minutes, and then cured by ultraviolet light under an inert atmosphere to form a release layer. The layer is then wound up to obtain the second intermediate film.

[0034] S3. Using atomized spraying, antistatic spray is evenly sprayed onto the surface of the scratch-resistant layer, and then introduced into an oven to dry, thereby obtaining the aforementioned PET protective film.

[0035] Optionally, in step S1, the coating amount of the photocurable adhesive is 6-10 g / m². 2 The coating amount of the three-proof coating adhesive is 3-5 g / m². 2 In step S2, the coating amount of the release silicone oil is 0.5-2 g / m². 2 .

[0036] By adopting the above technical solution, the coating amount of the photocurable adhesive can be controlled at 6-10 g / m².2 This process facilitates the construction of a full and uniform micro-grid, ensuring that the PET protective film possesses sufficient release force while also providing ample channels for air escape, achieving release bonding and efficient air venting. Secondly, the coating amount of the conformal coating is controlled at 3-5 g / m². 2 This approach helps ensure the PET protective film surface has good abrasion and scratch resistance while preventing the scratch-resistant layer from being too thick and affecting the overall flexibility. Additionally, controlling the application amount of release silicone oil to 0.5-2 g / m² is beneficial. 2 This ensures that the PET protective film has a stable and controllable light release force, and also reduces surface migration, ensuring that the PET protective film can be reused multiple times.

[0037] Thirdly, the application of the PET protective film provided in this application adopts the following technical solution:

[0038] An application of a PET protective film as a surface release protective film for electronic LCD or OLED screens.

[0039] In summary, the technical solution of this application has at least one of the following beneficial effects:

[0040] 1. By forming a grid layer with a grid shape on a film substrate and then coating a release layer on the surface of the grid layer, the resulting PET protective film not only has a good release effect with light release, but also maintains a high residual adhesion rate after multiple uses. At the same time, the overall protective film has a good air venting effect.

[0041] 2. By using a composition of isocyanate-terminated polyurethane prepolymer, methyl hydroxy acrylate and allyl epoxy polyether as the main photocurable resin, and in combination with other additives, the photocurable adhesive can simultaneously undergo free radical polymerization and cationic ring-opening polymerization, thereby forming a rigid-flexible balanced crosslinked network, which is beneficial to ensure the adhesion and long-term fatigue resistance of the mesh layer.

[0042] 3. By using a combination of acrylate polysiloxane and hyperbranched polysiloxane as the release oil for the release layer, the difference between release force and residual adhesion rate when using acrylate polysiloxane or hyperbranched polysiloxane alone as the release oil can be effectively balanced. This is beneficial for PET protective film to have a light release effect and excellent residual adhesion rate, and improves the overall release adhesion performance of PET protective film.

[0043] 4. By setting a grid structure with a specific arrangement direction and size in the grid layer, not only can the release contact area of ​​the PET protective film be reduced structurally, and the release force can be further controlled, but the recessed texture in the grid layer can also provide air exhaust channels, so that the PET protective film has better air exhaust performance when laminating. Attached Figure Description

[0044] Figure 1 This is a cross-sectional view of a PET protective film in Embodiment 1 of this application.

[0045] Figure 2 This is a schematic diagram of the mesh layer structure of a PET protective film in Embodiment 1 of this application.

[0046] Figure 3 This is a cross-sectional view of the film substrate and the mesh layer of a PET protective film in Embodiment 1 of this application.

[0047] Figure 4 This is a schematic diagram of the mesh layer structure of a PET protective film in Embodiment 3 of this application.

[0048] Explanation of reference numerals in the attached figures:

[0049] 1. Film substrate; 2. Mesh layer; 3. Release layer; 4. Anti-scratch layer; 5. Antistatic layer. Detailed Implementation

[0050] The present application will be further described in detail below with reference to the accompanying drawings, preparation examples, embodiments and comparative examples.

[0051] The terminal allyl epoxy polyether was specifically purchased from Klöln Chemical, with the specific brand name being KL-11.

[0052] The organotin catalyst was specifically selected as dibutyltin dilaurate; the acrylate leveling agent was purchased from Guangdong Shunde Shibang Jiaming Chemical Co., Ltd., with the brand name BZ6358N.

[0053] The acrylate polysiloxane was specifically purchased from Evonik in Germany, with the brand name TEGO RC902.

[0054] The hyperbranched polysiloxane was specifically purchased from Shin-Etsu Chemical Co., Ltd. of Japan, with the brand name X-62-7989.

[0055] The conformal coating adhesive was specifically selected from Elian Functional Materials, specifically the UV / moisture dual-curing polyurethane acrylate conformal coating, brand name COATING 9060-M.

[0056] The antistatic spray was specifically purchased from Briran New Materials, with the brand name HM-131B.

[0057] Preparation Example

[0058]

Preparation Example 1

[0059] An isocyanate-terminated polyurethane prepolymer is prepared by the following method:

[0060] Toluene diisocyanate was dissolved in N,N-dimethylformamide at 50 wt%. Polypropylene glycol PPG-400 was added at a molar ratio of NCO:OH = 1.2:1 and the mixture was stirred thoroughly. Then, dibutyltin dilaurate was added, and the mixture was heated to 95°C and stirred continuously for 2 hours. After the isocyanate value reached near the theoretical value, the mixture was distilled under reduced pressure and dried under vacuum to obtain an isocyanate-terminated polyurethane prepolymer.

[0061] In this preparation example, the amount of dibutyltin dilaurate added is 0.5% of the amount of polypropylene glycol PPG-400 added; the theoretical value is that after the hydroxyl groups in the system are completely reacted, the content of residual isocyanate groups in the system can be directly calculated.

[0062]

Preparation Example 2-1

[0063] A light-curing adhesive, comprising the following raw materials:

[0064] 65kg UV-curable resin, 30kg reactive diluent, 7.5kg photoinitiator, 0.05kg organotin catalyst, and 0.5kg acrylate leveling agent.

[0065] In this preparation example, the photocurable resin is a composition of isocyanate-terminated polyurethane prepolymer, hydroxypropyl methacrylate, and terminal allyl epoxy polyether, and the mass ratio of isocyanate-terminated polyurethane prepolymer, hydroxypropyl methacrylate, and terminal allyl epoxy polyether is 5:4:1, that is, it includes 32.5 kg of isocyanate-terminated polyurethane prepolymer, 26 kg of hydroxypropyl methacrylate, and 6.5 kg of terminal allyl epoxy polyether, wherein the isocyanate-terminated polyurethane prepolymer is specifically prepared from [Preparation Example 1].

[0066] In this preparation example, the reactive diluent is a composition of isodecaacrylate and tripropylene glycol diacrylate mixed in a 1:1 mass ratio, i.e., 15 kg of isodecaacrylate and 15 kg of tripropylene glycol diacrylate; the photoinitiator is a composition of photoinitiator 1173 and photoinitiator IRGACURE 250 mixed in a 2:1 mass ratio, i.e., 5 kg of photoinitiator 1173 and 2.5 kg of photoinitiator IRGACURE 250.

[0067] A method for preparing a photocurable adhesive includes the following steps:

[0068] Under light-protected conditions, the photocurable resin, reactive diluent, and catalyst are thoroughly mixed, heated to 83°C, and stirred thoroughly for 3 hours. Then, the temperature is lowered to 50°C, and the photoinitiator and acrylate leveling agent are added. The temperature is maintained and stirring is continued for 1 minute. After cooling, the photocurable adhesive is obtained and stored under light-protected conditions for later use.

[0069]

Preparation Example 2-2

[0070] A light-curing adhesive, comprising the following raw materials:

[0071] 50kg UV-curable resin, 24kg reactive diluent, 4kg photoinitiator, 0.08kg organotin catalyst, and 0.3kg acrylate leveling agent.

[0072] In this preparation example, the photocurable resin is a composition of isocyanate-terminated polyurethane prepolymer, hydroxypropyl methacrylate, and terminal allyl epoxy polyether, and the mass ratio of isocyanate-terminated polyurethane prepolymer, hydroxypropyl methacrylate, and terminal allyl epoxy polyether is 5:2:3, that is, it includes 25 kg of isocyanate-terminated polyurethane prepolymer, 10 kg of hydroxypropyl methacrylate, and 15 kg of terminal allyl epoxy polyether, wherein the isocyanate-terminated polyurethane prepolymer is specifically prepared from [Preparation Example 1].

[0073] In this preparation example, the reactive diluent is a composition of isodecaacrylate, 1,6-hexanediol diacrylate and trimethylolpropane triacrylate mixed in a mass ratio of 1:0.5:0.5, that is, including 12 kg of isodecaacrylate, 6 kg of 1,6-hexanediol diacrylate and 6 kg of trimethylolpropane triacrylate; the photoinitiator is a composition of photoinitiator 1173 and photoinitiator IRGACURE 250 mixed in a mass ratio of 3:1, that is, including 3 kg of photoinitiator 1173 and 1 kg of photoinitiator IRGACURE 250.

[0074] A method for preparing a photocurable adhesive includes the following steps:

[0075] Under light-protected conditions, the photocurable resin, reactive diluent, and catalyst are thoroughly mixed, heated to 75°C, and stirred thoroughly for 4 hours. Then, the temperature is lowered to 40°C, and the photoinitiator and acrylate leveling agent are added. The temperature is maintained and stirring is continued for 3 minutes. After cooling, the photocurable adhesive is obtained and stored under light-protected conditions for later use. Example

[0076]

Example 1

[0077] A PET protective film, reference Figure 1 It includes a thin film substrate 1, on one side of which a mesh layer 2 and a release layer 3 are sequentially disposed, and on the other side, an anti-scratch layer 4 and an anti-static layer 5 are sequentially disposed.

[0078] In this embodiment, the film substrate 1 is specifically selected as a PET film with a thickness of 75μm.

[0079] In this embodiment, the mesh layer 2 is specifically formed by coating and imprinting a photocurable adhesive onto one side of the film substrate 1 using an anilox roller, and then curing it by ultraviolet light irradiation. The photocurable adhesive is specifically prepared according to [Preparation Example 2-1]. Specifically, refer to... Figure 2 and Figure 3 The mesh layer 2 is composed of recessed patterns and raised grids. In this embodiment, the recessed patterns of the mesh layer 2 form an angle of 45° with the extension direction of the thin film substrate 1. The width a of the raised grid is 180 μm, the width b of the recessed pattern is 20 μm, and the depth c of the recessed pattern is 5 μm.

[0080] In this embodiment, the release layer 3 is specifically formed by applying release silicone oil to the surface of the mesh layer 2 using a conventional coating roller and then curing it. The release silicone oil is specifically selected as an acrylate polysiloxane release agent. By controlling the degree of curing of the release layer 3, the surface tension of the release layer 3 is made to reach 52-54 dynes.

[0081] In this embodiment, the scratch-resistant layer 4 is specifically formed by applying a three-proof coating adhesive to the side of the film substrate 1 opposite to the mesh layer 2 using a matte roller and then curing it. The antistatic layer 5 is formed by uniformly spraying an antistatic spray onto the surface of the scratch-resistant layer 4 and then drying and curing it.

[0082] A method for preparing a PET protective film includes the following steps:

[0083] S1. First, using an anilox roller coating method, in a light-protected state, a light-curing adhesive is evenly coated on one side of the film substrate 1 at a coating amount of 10 g / m2. During the coating process, the other side of the film substrate 1 is simultaneously cured by UV light to form a grid layer 2. Then, using a matte roller coating method, in a light-protected state, a three-proof coating adhesive is evenly coated on the side of the film substrate 1 away from the grid layer 2 at a coating amount of 5 g / m2. After coating, both sides of the film substrate 1 are simultaneously cured by UV light for a second time and the irradiation is continued for 30 seconds to form a scratch-resistant layer 4. At the same time, the grid layer 2 is fully cured. The film is then wound up to obtain the first intermediate film.

[0084] S2. Using a conventional coating roller, release silicone oil is uniformly coated onto the surface of the mesh layer 2 at a coating amount of 0.5-2 g / m2 under light-protected conditions. The actual amount of release silicone oil coated is related to the mesh spacing width and depth of the mesh layer 2. After coating, the release silicone oil is pre-baked in an oven at 60°C for 5 minutes, and then cured by ultraviolet light under a nitrogen atmosphere for 10 seconds to form release layer 3. The release layer is then rolled up to obtain the second intermediate film.

[0085] S3. Using atomized spraying, antistatic spray is evenly sprayed onto the surface of the anti-scratch layer 4, and then dried in an oven at 80°C for 3 minutes. The film is then rolled up to obtain the PET protective film.

[0086]

Example 2

[0087] A PET protective film differs from [Example 1] in that the mesh layer 2 and release layer 3 are different, as well as the preparation method is different.

[0088] In this embodiment, the photocurable adhesive used to form the mesh layer 2 is specifically prepared according to [Preparation Example 2-2]. Specifically, the width a of the formed mesh is 160 μm, the spacing b between adjacent meshes is 30 μm, and the spacing depth c is 10 μm.

[0089] In this embodiment, the release silicone oil used to form the release layer 3 is specifically a composition of acrylate polysiloxane release agent and hyperbranched polysiloxane release agent, wherein the mixing mass ratio of acrylate polysiloxane and hyperbranched polysiloxane release agent is 1:0.6. By controlling the degree of curing of the release layer 3, the surface tension of the release layer 3 is made to reach 54-56 dynes.

[0090] A method for preparing a PET protective film includes the following steps:

[0091] S1. First, using an anilox roller coating method, in a light-protected state, a light-curing adhesive is evenly coated on one side of the film substrate 1 at a coating amount of 6 g / m2. During the coating process, the other side of the film substrate 1 is simultaneously cured by UV light to form a grid layer 2. Then, using a matte roller coating method, in a light-protected state, a three-proof coating adhesive is evenly coated on the side of the film substrate 1 away from the grid layer 2 at a coating amount of 3 g / m2. After the coating is completed, both sides of the film substrate 1 are simultaneously cured by UV light for a second time and the irradiation is continued for 20 seconds to form a scratch-resistant layer 4. At the same time, the grid layer 2 is fully cured. The film is then wound up to obtain the first intermediate film.

[0092] S2. Using a conventional coating roller, release silicone oil is uniformly coated onto the surface of the mesh layer 2 at a coating amount of 0.5-2 g / m2 under light-protected conditions. The actual amount of release silicone oil coated is related to the mesh spacing width and depth of the mesh layer 2. After coating, the release silicone oil is pre-baked in an oven at 70°C for 3 minutes, and then cured by ultraviolet light under a nitrogen atmosphere for 10 seconds to form release layer 3. The release layer is then rolled up to obtain the second intermediate film.

[0093] S3. Using atomized spraying, antistatic spray is evenly sprayed onto the surface of the anti-scratch layer 4, and then dried in an oven at 80°C for 3 minutes. The film is then rolled up to obtain the PET protective film.

[0094]

Example 3

[0095] A PET protective film, which differs from [Example 1] in that the mesh layer 2 is different.

[0096] In this embodiment, refer to Figure 4 The longitudinal grooves of the mesh layer 2 are in the same direction as the extension of the thin film substrate 1, that is, the longitudinal grooves are parallel to the edge of the thin film substrate 1.

[0097]

Example 4

[0098] A PET protective film, which differs from [Example 1] in that the mesh layer 2 is different.

[0099] In this embodiment, the width a of the raised grid is 300 μm, the width b of the recessed texture is 20 μm, and the depth c of the recessed texture is 5 μm.

[0100]

Example 5

[0101] A PET protective film, which differs from [Example 1] in that the mesh layer 2 is different.

[0102] In this embodiment, the width a of the raised grid is 180 μm, the width b of the recessed texture is 10 μm, and the depth c of the recessed texture is 2 μm.

[0103]

Example 6

[0104] A PET protective film, which differs from [Example 1] in that the release layer 3 is different.

[0105] In this embodiment, the release silicone oil used to form the release layer 3 is specifically selected as hyperbranched polysiloxane.

[0106]

Example 7

[0107] A PET protective film, which differs from [Example 1] in that the release layer 3 is different.

[0108] In this embodiment, the release silicone oil used to form the release layer 3 is specifically a composition of acrylate polysiloxane release agent and hyperbranched polysiloxane release agent, wherein the mixing mass ratio of acrylate polysiloxane and hyperbranched polysiloxane release agent is 1:1. Comparative Example

[0109] Comparative Example 1

[0110] A PET protective film, which differs from [Example 1] in that it does not have a mesh layer 2.

[0111] In this comparative example, an adhesive layer is used instead of the mesh layer 2. Specifically, the adhesive layer is formed by coating a light-curing adhesive onto one side of the film substrate 1 with a coating roller and curing it by ultraviolet light irradiation. The light-curing adhesive is specifically prepared according to [Preparation Example 2-1].

[0112] Comparative Example 2

[0113] A PET protective film, which differs from [Example 1] in that it does not have a release layer 3.

[0114] Application examples

[0115]

Application Example 1

[0116] An application of a PET protective film, using the PET protective film prepared in [Example 1], is specifically used as a surface release protective film for screen components such as electronic liquid crystal displays or OLED screens. During actual lamination, the film is slowly laminated from its edge along its extension direction.

[0117] Performance test data

[0118] 1. 180° Peel Force Test: The test was conducted according to Chapter 8 of GB / T 25256-2010 "Test Method for 180° Peel Force and Residual Adhesion of Optical Functional Film Release Film". The 180° peel force (g / inch) of the PET protective film prepared in each example and comparative example was recorded, and the results were rounded to one decimal place. A clean tempered glass plate was used as the test plate to simulate the state of PET protective film adhering to an electronic liquid crystal screen.

[0119] 2. Repeatability of adhesion: The test was conducted according to Chapter 8 of GB / T 25256-2010 Test method for 180° peel force and residual adhesion of optical functional film release film. Before the test, the PET protective film was repeatedly bonded and completely peeled off on a clean tempered glass plate 10 times. Then the residual adhesion rate test was carried out, and the residual adhesion rate (%) of the PET protective film prepared in each example and comparative example after multiple bonding was recorded. The results were rounded to the nearest integer.

[0120] 3. Air Exhaust Performance: A 75-inch clean tempered glass plate was selected as the test plate. In a dust-free environment, the PET protective film prepared in each embodiment and comparative example was fully adhered to the test plate. During adhesion, the film was gradually adhered starting from the edge and extending along its direction. After adhesion, the presence of air bubbles between the PET protective film and the test plate was observed and recorded. If there were no air bubbles overall, it was recorded as "No obvious air bubbles"; if there were fewer than 5 air bubbles and none were larger than 3mm, it was recorded as "Small number of air bubbles"; if there were 5 or more air bubbles, or if any single air bubble was larger than 3mm, it was recorded as "Numerous air bubbles".

[0121] Table 1. Partial performance test data of PET protective film

[0122]

[0123] Based on Examples 1 and Comparative Examples 1-2, and the test data in Table 1, it can be seen that by using the photocurable adhesive prepared in the preparation example to form a grid layer 2 with a grid shape on the film substrate 1, and then coating the surface of the grid layer 2 with a specific release silicone oil, the resulting PET protective film exhibits good light release effect and maintains a high residual adhesion rate even after multiple uses. Furthermore, the overall protective film demonstrates good venting performance. As shown in Comparative Example 1, the grid structure of the grid layer 2 not only structurally reduces the release contact area and appropriately lowers the release force after overall bonding, achieving a light release effect, but also provides air venting channels. This gives the PET protective film superior venting performance during bonding, which is beneficial for its application on screen element protective films that require sufficient release. It also ensures that there are no air bubbles on the surface of the screen element after bonding, thus improving its appearance performance after bonding.

[0124] Combining Examples 1-3 with the detection data in Table 1, it can be seen that, as Figure 2 and Figure 4 As shown, when the direction of the recessed texture of the grid layer 2 forms a 45° angle with the edge of the film substrate 1, the resulting PET protective film exhibits superior venting performance compared to when the longitudinal recessed texture is parallel to the edge of the film substrate 1. This may be related to the lamination method of the PET protective film. Conventional lamination begins from the edge of the PET protective film and gradually extends along its direction. When the recessed texture of the grid layer forms a 45° angle with the edge of the film substrate 1, and a conventional lamination method is used, the recessed texture of the grid layer directly points towards and leads to the edge of the film, providing a continuous, short, straight, and least-resistance escape channel for air. This facilitates the guidance of air between the PET protective film and the tempered glass plate to escape from multiple directions during the lamination process, effectively preventing air bubble residue.

[0125] Furthermore, combining Examples 1 and 4-5 with the test data in Table 1, it can be seen that when the width a of the raised grids in the mesh layer 2 is 160-180 μm, the width b of the recessed texture is 20-30 μm, and the depth c of the recessed texture is 5-10 μm, the venting performance of the resulting PET protective film is also superior. As shown in Example 4, when the raised grids in the mesh layer 2 are too large, the proportion of recessed textures formed by the mesh layer 2 is small, which affects the venting performance of the PET protective film. Similarly, as shown in Example 5, when the width and depth of the recessed textures in the mesh layer 2 are insufficient, the resulting venting grooves are also small, which, under the same lamination process, also affects the venting performance of the PET protective film.

[0126] Based on Examples 1 and 6-7 and the test data in Table 1, it can be seen that when a composition of acrylate polysiloxane and hyperbranched polysiloxane is used as the release silicone oil, the resulting release layer 3 can give the PET protective film a light release force and excellent residual adhesion rate. It can effectively balance the relationship between release force and residual adhesion rate when using acrylate polysiloxane or hyperbranched polysiloxane alone as the release silicone oil, which is beneficial to improving the overall release adhesion performance of the PET protective film.

[0127] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this specific embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A PET protective film, characterized in that: The film includes a thin film substrate (1) and a mesh layer (2) and a release layer (3) sequentially coated on one side of the thin film substrate (1). The thin film substrate (1) is a PET film. The mesh layer (2) is formed by coating and imprinting a photocurable adhesive onto one side of the thin film substrate (1) with an anilox roller and curing it by ultraviolet light. The release layer (3) is formed by coating the surface of the mesh layer (2) with release silicone oil. The photocurable adhesive comprises the following raw materials in parts by weight: UV-curable resin: 60-65 parts; Reactive diluent: 25-30 parts; Photoinitiator: 4-7.5 parts; Organotin catalyst: 0.05-0.08 parts; Acrylic leveling agent: 0.3-0.8 parts; The coating amount of the photocurable adhesive is 6-10 g / m². 2 The photocurable resin is a composition of isocyanate-terminated polyurethane prepolymer, methyl hydroxy acrylate and allyl epoxy polyether, wherein the mass ratio of isocyanate-terminated polyurethane prepolymer, methyl hydroxy acrylate and allyl epoxy polyether is 5:(2-4):(1-3). The isocyanate-terminated polyurethane prepolymer is prepared by the following method: Toluene diisocyanate was dissolved in a solvent, polypropylene glycol was added and stirred thoroughly, then a catalyst was added, the mixture was heated and stirred continuously until the isocyanate value reached near the theoretical value, then the mixture was distilled under reduced pressure and dried under vacuum to obtain isocyanate-terminated polyurethane prepolymer. The coating amount of the release silicone oil is 0.5-2 g / m². 2 The release silicone oil is a composition of acrylate polysiloxane and hyperbranched polysiloxane, and the mass ratio of acrylate polysiloxane to hyperbranched polysiloxane is 1:(0.6-1). The mesh layer (2) is composed of recessed textures and raised grids. The width of the raised grids is 160-180μm, the width of the recessed textures is 20-30μm, and the depth of the recessed textures is 2-10μm.

2. The PET protective film according to claim 1, characterized in that: In the photocurable adhesive, the reactive diluent is at least one of tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, and isodecyl acrylate; the photoinitiator is at least one of photoinitiator 1173 or photoinitiator IRGACURE 250.

3. The PET protective film according to claim 2, characterized in that: The method for preparing the photocurable adhesive includes the following steps: Under light-protected conditions, the photocurable resin, reactive diluent, and organotin catalyst are thoroughly mixed and heated to 75-83°C. The mixture is stirred thoroughly for 3-4 hours, then the temperature is lowered to 40-55°C. A photoinitiator and acrylate leveling agent are added, and the mixture is stirred for 1-3 minutes while maintaining the temperature. After cooling, the photocurable adhesive is obtained and stored under light-protected conditions for later use.

4. The PET protective film according to claim 1, characterized in that: The surface tension of the release layer (3) is 52-56 dynes.

5. A PET protective film according to any one of claims 1-4, characterized in that: The thin film substrate (1) is further provided with a scratch-resistant layer (4) and an antistatic layer (5) on the side opposite to the mesh layer (2). The anti-scratch layer (4) is formed by coating the film substrate (1) with a three-proof coating adhesive on the side away from the mesh layer (2) and then curing it, and the anti-scratch layer (4) has a frosted surface structure. The antistatic layer (5) is formed by uniformly atomizing and spraying antistatic spray onto the surface of the scratch-resistant layer (4) and then drying and curing it.

6. A method for preparing a PET protective film, used to prepare the PET protective film as described in claim 5, characterized in that, Includes the following steps: S1. First, using an anilox roller coating method, the photocurable adhesive is coated on one side of the film substrate (1) in a light-protected state. At the same time, the other side of the film substrate (1) is irradiated and cured for the first time with ultraviolet light to form a grid layer (2). Then, using a matte roller coating method, the three-proof coating adhesive is coated on the side of the film substrate (1) away from the grid layer (2) in a light-protected state. After the coating is completed, the two sides of the film substrate (1) are irradiated and cured for the second time with ultraviolet light to form a scratch-resistant layer (4). The grid layer (2) is fully cured and then wound up to obtain the first intermediate film. S2. Using a coating roller, release silicone oil is coated on the surface of the mesh layer (2) in a light-proof state. Then, it is placed in an oven at 60-70℃ for 3-5 minutes for pre-baking. Then, it is cured by ultraviolet light under an inert atmosphere to form a release layer (3). The layer is then wound up to obtain the second intermediate film. S3. Using atomized spraying, the antistatic spray is evenly sprayed onto the surface of the anti-scratch layer (4), and then placed in an oven to dry, thus obtaining the PET protective film.

7. The method for preparing a PET protective film according to claim 6, characterized in that: In step S1, the coating amount of the three-proof coating adhesive is 3-5 g / m². 2 .

8. An application of the PET protective film as described in claim 5, characterized in that: As a surface release protective film for electronic LCD or OLED screens.

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