A fluorosilicone release agent and its preparation method, along with a fluorosilicone release coating solution and release film.

Abstract

This invention relates to the field of polymer materials technology, and particularly to fluorosilicone release agents, their preparation methods, fluorosilicone release coating solutions, and release films. The preparation method of the fluorosilicone release agent includes the following steps: using fluorinated monomers, cyclic siloxanes, linear hydrogen-containing siloxanes, and nano-silica as raw materials, a cationic ring-opening polymerization reaction is carried out to prepare a terminal hydrogen-containing fluorinated polysiloxane; using the terminal hydrogen-containing fluorinated polysiloxane and a siloxane with unsaturated bonds as raw materials, a hydrosilylation reaction is carried out to prepare the fluorosilicone release agent. The preparation method of the fluorosilicone release agent provided by this invention is simple and controllable. The prepared fluorosilicone release agent can form a stable chemical bond with PET, thereby imparting excellent release properties to the film without affecting its mechanical properties.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a fluorosilicone release agent, its preparation method, a fluorosilicone release coating liquid, and a release film. Background Technology

[0002] Release agents are substances that effectively reduce the adhesion between two solid surfaces. They are typically applied to a substrate in the form of a coating to prevent sticking. Due to their superior anti-stick properties, release agents are widely used in pressure-sensitive labels and tapes, medical materials, anti-fouling treatments, electronic equipment, and communications, among other fields.

[0003] Biaxially oriented polyester (BOPET) film is widely used in packaging, electronics, optics, and many other fields due to its excellent mechanical properties, heat resistance, dimensional stability, and optical properties. Among these applications, release film is one of the important uses of BOPET film. It is typically prepared by adding masterbatch containing release agent during the polyester film manufacturing process, giving it low surface tension and peelability.

[0004] Because the compatibility between the active release agent components (such as siloxanes, fluoropolymers, etc.) in existing release masterbatches and the PET matrix resin is generally poor, the addition of release masterbatches will affect the mechanical properties of the film and limit the application of release films.

[0005] Therefore, how to achieve good release properties of the film without damaging its mechanical properties is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the problem that the addition of release masterbatch affects the mechanical properties of films in existing technologies, this invention provides a method for preparing a fluorosilicone release agent. The fluorosilicone release agent prepared by this method can form a stable chemical bond with PET, and solves the compatibility problem between the release agent and PET through interfacial chemical anchoring, thus resolving the problem that the addition of release masterbatch affects the mechanical properties of films in existing technologies.

[0007] The technical solution adopted by this invention to solve its technical problem is: A method for preparing a fluorosilicone release agent includes the following steps: using fluorinated monomers, cyclic siloxanes, linear hydrogen-containing siloxanes, and nano-silica as raw materials, a cationic ring-opening polymerization reaction is carried out to prepare a terminal hydrogen-containing fluorinated polysiloxane; using the terminal hydrogen-containing fluorinated polysiloxane and a siloxane with unsaturated bonds as raw materials, a hydrosilylation reaction is carried out to prepare a fluorosilicone release agent.

[0008] Optionally, the fluorine monomer is trifluoropropylcyclotrisiloxane.

[0009] Optionally, the cyclic siloxane is octamethylcyclotetrasiloxane.

[0010] Optionally, the linear hydrogen-containing siloxane is tetramethyldihydrodisiloxane.

[0011] Optionally, the nano-silica is APTES / SiO2 nanoparticles.

[0012] Optionally, the siloxane with unsaturated bonds is vinyltrimethoxysilane.

[0013] Another object of the present invention is to provide a fluorosilicone release agent, which is prepared by the method for preparing fluorosilicone release agents as described above.

[0014] Another object of the present invention is to provide a fluorosilicone release coating liquid, comprising the fluorosilicone release agent as described above.

[0015] Optionally, the product comprises the following components by weight: 20-40 parts of the fluorosilicone release agent; Wetting agent 0.1-1.0 parts; 50-80 parts of n-heptane.

[0016] Another object of the present invention is to provide a release film, comprising a base film and a release layer disposed on the surface of the base film; the release layer is prepared by means of a fluorosilicone release coating liquid as described in claim 8 or 9.

[0017] The beneficial effects of this invention are: The method for preparing the fluorosilicone release agent provided by this invention is simple and controllable. The prepared fluorosilicone release agent can form a stable chemical bond with PET, thereby giving the film excellent release properties without affecting the film's mechanical properties. Detailed Implementation

[0018] The present invention will now be described in further detail. The embodiments described below are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0019] To address the problem that the addition of release masterbatch affects the mechanical properties of films in existing technologies, this invention provides a method for preparing a fluorosilicone release agent. This method includes the following steps: using fluorinated monomers, cyclic siloxanes, linear hydrogen-containing siloxanes, and nano-silica as raw materials, a cationic ring-opening polymerization reaction is conducted to prepare a hydrogen-terminated fluorinated polysiloxane; using the hydrogen-terminated fluorinated polysiloxane and a siloxane with unsaturated bonds as raw materials, a hydrosilylation reaction is conducted to prepare the fluorosilicone release agent.

[0020] In this preparation process, fluorinated monomers and cyclic siloxanes are used as polymerizing monomers, and linear hydrogen-containing siloxanes are used as end-capping agents. Through cationic ring-opening polymerization, active hydrogen-terminated fluorinated polysiloxanes are prepared. In this process, modified nano-silica is introduced by in-situ dispersion, which helps to improve the release performance of the coating. Then, the hydrogen-terminated fluorinated polysiloxane is reacted with siloxanes with unsaturated bonds through hydrosilylation to obtain a fluorosilicone release agent.

[0021] This fluorosilicone release agent comprises a polysiloxane structure and fluorinated groups. The polysiloxane structure provides basic release properties, while the fluorinated groups further reduce surface energy. Combined with introduced nano-silica, the synergistic effect of these components enables the prepared release agent to impart excellent release properties to BOPET release films. Furthermore, this fluorosilicone release agent can form a stable chemical bond with PET, solving the compatibility problem between the release agent and PET through interfacial chemical anchoring, and further preventing the addition of the release agent from affecting the mechanical properties of the film.

[0022] The method for preparing the fluorosilicone release agent provided by this invention is simple and controllable. The prepared fluorosilicone release agent can form a stable chemical bond with PET, thereby giving the film excellent release properties without affecting the film's mechanical properties.

[0023] Furthermore, the preferred fluorine monomer of this invention is trifluoropropylcyclotrisiloxane (D3F). The trifluoropropyl group in trifluoropropylcyclotrisiloxane has a low surface energy, which can effectively reduce the surface tension of the fluorosilicone release agent, giving the release film surface excellent anti-sticking properties and meeting high release requirements. At the same time, the cyclic structure of trifluoropropylcyclotrisiloxane has moderate ring-opening polymerization activity, which can copolymerize with cyclic siloxanes and linear hydrogen-containing siloxanes under the action of cationic initiators, which is beneficial to the smooth progress of the polymerization reaction and the stability of the product structure. In addition, the introduction of trifluoropropyl groups can significantly improve the temperature resistance and solvent resistance of the fluorosilicone release agent.

[0024] The preferred cyclic siloxane of this invention is octamethylcyclotetrasiloxane (D4). Octamethylcyclotetrasiloxane is a common silicone raw material with ample market supply and relatively low price, which can effectively control the production cost of the product. At the same time, octamethylcyclotetrasiloxane has high ring-opening polymerization activity and good copolymerization compatibility with trifluoropropylcyclotrisiloxane and linear hydrogen-containing siloxanes, which can form copolymer molecular chains with uniform structure, ensuring the stability of product performance. The dimethylsiloxane segments introduced by octamethylcyclotetrasiloxane have good flexibility, which enables the fluorosilicone release agent to maintain excellent release performance while possessing good flexibility, avoiding problems such as cracking and peeling of the release layer during bending and stretching.

[0025] The preferred linear hydrogen-containing siloxane of this invention is tetramethyldihydrodisiloxane (TMDSO). As a chain terminator, TMDSO can precisely control the molecular weight of the polymer in cationic ring-opening polymerization and introduce silane-hydrogen bonds at both ends of the molecular chain, providing active sites for subsequent hydrosilylation reactions and ensuring the efficient execution of the second step reaction. The moderate silane-hydrogen bond activity of TMDSO allows it to terminate the reaction with the active chain in ring-opening polymerization without causing side reactions during polymerization, thus ensuring the structural purity of the terminal hydrogen-containing fluorinated polysiloxane. By adjusting the amount of TMDSO added, the molecular weight of the terminal hydrogen-containing fluorinated polysiloxane can be flexibly controlled, thereby adjusting the viscosity and performance of the final fluorosilicone release agent to meet the needs of different application scenarios.

[0026] Furthermore, the present invention preferably uses APTES / SiO2 nanoparticles as nano-silica. After surface modification of nano-silica with APTES (3-aminopropyltriethoxysilane), organic functional groups are introduced on the surface of nano-silica, which can significantly improve the interfacial compatibility between nano-silica and organofluorosilicone polymers, prevent the nanoparticles from agglomerating in the polymer, and ensure their uniform dispersion. The uniformly dispersed APTES / SiO2 nanoparticles can act as physical crosslinking points between the molecular chains of fluorosilicone release agents, improve the mechanical strength and wear resistance of the release agent, and extend the service life of the release film. The nano-silica with APTES surface modification can form micro-nano structures on the coating surface, improving the release performance of the coating.

[0027] The preferred method for preparing APTES / SiO2 nanoparticles in this invention is as follows: 1-2 g of dried silica nanoparticles were ultrasonically dispersed in 30-50 mL of ethanol to obtain an ethanol solution containing the silica nanoparticles. 2-4 g of APTES was dissolved in 20-30 mL of a mixture (ethanol and water in a volume ratio of 15:5) to prepare a hydrolyzed APTES sol. 10 mL of the ethanol solution containing the silica nanoparticles was taken, and 4-6 mL of the APTES sol was added. 2-4 mL of acetic acid was added as a catalyst, and the mixture was refluxed at 50-60°C and 4-5°C for 2-3 hours with magnetic stirring to complete the silanization reaction. The resulting sol was then centrifuged at 7000 rpm for 15 minutes, washed three times with an ethanol-distilled water mixture, and finally dried in a 75°C vacuum oven for 24 hours to obtain APTES-modified silica nanoparticles.

[0028] The preferred siloxane with unsaturated bonds in this invention is vinyltrimethoxysilane. The vinyl groups in vinyltrimethoxysilane have high hydrosilylation reactivity, which can react rapidly with the hydrogen-silicon bonds of fluorinated polysiloxanes with terminal hydrogen, thereby improving reaction efficiency and shortening the production cycle. The trimethoxysilane groups in vinyltrimethoxysilane can undergo hydrolysis-condensation reaction during curing to form a cross-linked structure, which improves the curing degree and solvent resistance of the release layer, making the performance of the release film more stable. The introduction of vinyltrimethoxysilane can further adjust the molecular structure of the fluorosilicone release agent and improve the release performance of the coating.

[0029] Specifically, the preferred preparation process of the fluorosilicone release agent of this invention can be carried out according to the following method: 12-14 g of trifluoropropylcyclotrisiloxane (D3F), 8-10 g of octamethylcyclotetrasiloxane (D4), 0.2-0.4 g of tetramethyldihydrodisiloxane (TMDSO), and 1-3 g of modified SiO2 were placed in a dry 100 mL three-necked flask. The system was sealed and purged with nitrogen. The system was placed in an oil bath and heated to 75 °C, and stirred for 30 min to maintain a constant temperature. Then, an appropriate amount of trifluoromethanesulfonic acid (5% of the total molar amount of the monomers) was added as a catalyst, and the reaction was continued at 75 °C for 8 h. After the reaction was completed, the system was allowed to cool completely, and n-heptane was added to dilute and neutralize the acid in the system. The solution was then filtered and distilled to remove the solvent. The solution was then subjected to reduced pressure at 180 °C for 30 min to remove low-boiling-point molecules, yielding a fluorinated polysiloxane with terminal hydrogen. Take 2g of the synthesized hydrogen-terminated fluorinated polysiloxane and place it in a 100mL dry three-necked flask. Add excess vinyltrimethoxysilane, 5ppm Karstedt catalyst, and 5mL of solvent 1,3-bis(trifluoromethyl)benzene. Place the system in an oil bath with a condenser and heat to 80℃ for 10 hours. After the reaction is complete, remove the solvent by distillation at 116℃ to obtain the single-component fluorosilicone release agent.

[0030] The fluorosilicone release agent provided by this invention is a single-component self-crosslinking fluorosilicone release agent that can self-crosslink and cure without the need for crosslinking agents and anchoring agents.

[0031] Another object of the present invention is to provide a fluorosilicone release agent, which is prepared by the method for preparing fluorosilicone release agents as described above.

[0032] The fluorosilicone release agent provided by this invention can form a stable chemical bond with PET, thereby imparting excellent release properties to the film without affecting its mechanical properties.

[0033] Another object of the present invention is to provide a fluorosilicone release coating liquid comprising the fluorosilicone release agent as described above.

[0034] Furthermore, the present invention preferably includes a fluorosilicone release coating liquid, characterized in that it comprises the following components by weight: 20-40 parts of fluorosilicone release agent; Wetting agent 0.1-1.0 parts; 50-80 parts of n-heptane.

[0035] This fluorosilicone release coating liquid has suitable surface tension and viscosity, good spreadability on the substrate surface, uniform coating, and consistent release layer thickness, effectively ensuring the release performance of the release film. The release liquid with this component ratio has good compatibility between the components, is not prone to delamination or precipitation, has high storage stability, and can ensure the excellent performance of the release liquid.

[0036] The preferred wetting agent of the present invention is selected from one or more of TL-J20, TL-J40 and X-405.

[0037] Another object of the present invention is to provide a release film comprising a base film and a release layer disposed on the surface of the base film; wherein the release layer is prepared by means of a fluorosilicone release coating solution as described above.

[0038] Specifically, the release film can be prepared according to the following process: Step 1: Preparation of the base film. Open-face masterbatch and PET chips are mixed uniformly at a specific mass ratio to form the ABA structure surface layer of the PET film. The masterbatch mass percentage in the surface layer is 60-90%. The thickness and masterbatch percentage of the upper and lower surface layers are the same. The core layer is made of pure PET chips, with a core layer to surface layer thickness ratio of 1:9. The raw material melt is first extruded and cast, then biaxially stretched, heat-set, and surface corona treated to obtain a transparent BOPET film. The longitudinal stretching temperature is 70-100℃, and the stretching ratio is 3-3.5 times. The transverse stretching temperature is 100-120℃, and the stretching ratio is 3-4 times. The heat-setting temperature is 190-230℃, and the time is 10-20 seconds, ultimately preparing a 50-micron BOPET base film. Throughout the preparation process, it is crucial to maintain a clean environment to avoid impurities affecting the film's performance. Simultaneously, careful control of the operating parameters at each step is essential to ensure stable film quality.

[0039] Step Two: Online Coating: Coating is performed using a Gravure concave coating roller. An online coating station (including a corona treatment device and a coating device) is located between the longitudinal and transverse stretching of the BOPET film. After the PET film is corona-treated, the coating device evenly coats the PET surface with the coating liquid. Then, during transverse stretching and heat setting, the coating is cured and cross-linked, forming a release coating on the PET film surface, resulting in a 50-micron-thick BOPET film. Throughout the entire preparation process, it is crucial to maintain a clean environment to avoid the influence of impurities on the film's performance. Simultaneously, careful control of the operating parameters at each step is essential to ensure stable film quality.

[0040] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below.

[0041] Unless otherwise specified, the PET chips in the embodiments and comparative examples of this invention are all Yizheng Chemical Fiber FG604, the open masterbatch is all Yizheng Chemical Fiber FG611, and the wetting agent is all TL-J20.

[0042] Unless otherwise specified, the APTES / SiO2 nanoparticles in the embodiments and comparative examples of this invention were prepared according to the following method: 1.5 g of dried silica nanoparticles were ultrasonically dispersed in 40 mL of ethanol to obtain an ethanol solution containing the silica nanoparticles. 3 g of APTES was dissolved in 25 mL of a mixture (ethanol and water in a volume ratio of 15:5) to prepare a hydrolyzed APTES sol. 10 mL of the ethanol solution containing the silica nanoparticles was taken, 5 mL of the APTES sol was added, and 3 mL of acetic acid was added as a catalyst. The mixture was refluxed at 55°C (4-5℃) for 2.5 hours with magnetic stirring to complete the silanization reaction. The resulting sol was then centrifuged at 7000 rpm for 15 minutes, washed three times with an ethanol-distilled water mixture, and finally dried in a 75°C vacuum oven for 24 hours to obtain APTES-modified silica nanoparticles. Example 1

[0043] This embodiment provides a method for preparing a release film, including the following steps: Step 1: Preparation of fluorosilicone release coating solution. A fluorosilicone release coating solution was prepared by combining 20 parts by weight of fluorosilicone release agent, 0.5 parts by weight of wetting agent, and 79.5 parts by weight of n-heptane.

[0044] The fluorosilicone release agent is prepared according to the following method: 12 g of trifluoropropylcyclotrisiloxane (D3F), 8 g of octamethylcyclotetrasiloxane (D4), 0.2 g of tetramethyldihydrodisiloxane (TMDSO), and 1 g of APTES / SiO2 nanoparticles were placed in a dry 100 mL three-necked flask. The system was sealed and purged with nitrogen. The system was placed in an oil bath and heated to 75 °C, and stirred for 30 min to maintain a constant temperature. Then, an appropriate amount of trifluoromethanesulfonic acid catalyst (5% of the total molar amount of monomers) was added, and the reaction was continued at 75 °C for 8 h. After the reaction was completed, the system was allowed to cool completely, and n-heptane was added to dilute and neutralize the acid in the system. The solution was then filtered and distilled to remove the solvent. The solution was then subjected to reduced pressure at 180 °C for 30 min to remove low-boiling-point molecules, yielding a fluorinated polysiloxane with terminal hydrogen. Take 2g of the synthesized hydrogen-terminated fluorinated polysiloxane and place it in a 100mL dry three-necked flask. Add excess vinyltrimethoxysilane, 5ppm Karstedt catalyst, and 5mL of solvent 1,3-bis(trifluoromethyl)benzene. Place the system in an oil bath with a condenser and heat to 80℃ for 10 hours. After the reaction is complete, remove the solvent by distillation at 116℃ to obtain the single-component fluorosilicone release agent.

[0045] Step 2: Preparation of the base film. Open-ended masterbatch and PET chips are mixed uniformly at a specific mass ratio to form the surface layer of the ABA structure PET film. The masterbatch accounts for 90% of the surface layer's mass. The upper and lower surface layers have the same thickness and masterbatch proportion. The core layer is made of pure PET chips, with a core layer to surface layer thickness ratio of 1:9. The raw material melt is first extruded and cast, then the base film undergoes biaxial stretching and heat setting. The longitudinal stretching temperature is 70℃, with a stretching ratio of 3 times. The transverse stretching temperature is 100℃, with a stretching ratio of 3 times. The heat setting temperature is 190℃ for 10 seconds, ultimately yielding a 50-micron-thick base film.

[0046] Step 3: Online Coating: Coating is performed using a Gravure concave coating roller. An online coating station (including a corona treatment device and a coating device) is set between the longitudinal and transverse stretching of the BOPET film. After the PET film is corona-treated by the corona treatment device, the coating device evenly coats the PET surface with the coating liquid. Then, during the transverse stretching and heat setting process, it is cured and cross-linked, forming a release coating on the surface of the PET film, resulting in a BOPET film with a thickness of 50 micrometers, denoted as Sample 1. Throughout the preparation process, it is necessary to maintain a clean environment to avoid the influence of impurities on the film performance. At the same time, it is also important to control the operating parameters of each step to ensure the stability of the film quality.

[0047] Comparative Example 1 This comparative example provides a method for preparing a release film, comprising the following steps: Step 1: Preparation of fluorosilicone release coating solution. A release coating solution was prepared by combining 20 parts by weight of fluorosilicone release agent, 0.5 parts by weight of wetting agent, and 79.5 parts by weight of n-heptane.

[0048] The fluorosilicone release agent is prepared according to the following method: 12g of trifluoropropylcyclotrisiloxane (D3F), 8g of octamethylcyclotetrasiloxane (D4), and 0.2g of tetramethyldihydrodisiloxane (TMDSO) were placed in a dry 100mL three-necked flask. The system was sealed and purged with nitrogen. The system was placed in an oil bath and heated to 75°C, and stirred for 30 min to maintain a constant temperature. Then, an appropriate amount of trifluoromethanesulfonic acid (5% of the total molar amount of the monomers) was added as a catalyst, and the reaction was continued at 75°C for 8 h. After the reaction was completed, the system was allowed to cool completely, and n-heptane was added to dilute and neutralize the acid in the system. The mixture was then filtered and distilled to remove the solvent. The solution was then subjected to reduced pressure at 180°C for 30 min to remove low-boiling-point molecules, yielding a fluorinated polysiloxane with terminal hydrogen. 2g of the synthesized fluorinated polysiloxane with terminal hydrogen was placed in a dry 100mL three-necked flask, and excess vinyltrimethoxysilane, 5ppm Karstedt catalyst, and 5mL of 1,3-bis(trifluoromethyl)benzene solvent were added. The system was placed in an oil bath with a condenser installed, and the temperature was raised to 80°C for 10 hours. After the reaction was completed, the solvent was removed by distillation at 116°C to obtain the single-component fluorosilicone release agent.

[0049] Step 2: Preparation of the base film. Open-ended masterbatch and PET chips are mixed uniformly at a specific mass ratio to form the surface layer of the ABA structure PET film. The masterbatch accounts for 90% of the surface layer's mass. The upper and lower surface layers have the same thickness and masterbatch proportion. The core layer is made of pure PET chips, with a core layer to surface layer thickness ratio of 1:9. The raw material melt is first extruded and cast, then the base film undergoes biaxial stretching and heat setting. The longitudinal stretching temperature is 70℃, with a stretching ratio of 3 times. The transverse stretching temperature is 100℃, with a stretching ratio of 3 times. The heat setting temperature is 190℃ for 10 seconds, ultimately yielding a 50-micron-thick base film.

[0050] Step 3: Online Coating: Coating is performed using a Gravure concave coating roller. An online coating station (including a corona treatment device and a coating device) is set between the longitudinal and transverse stretching of the BOPET film. After the PET film is corona-treated by the corona treatment device, the coating device evenly coats the PET surface with the coating liquid. Then, during the transverse stretching and heat setting process, it is cured and cross-linked, forming a release coating on the surface of the PET film, resulting in a BOPET film with a thickness of 50 micrometers, designated as Sample 2. Throughout the preparation process, it is necessary to maintain a clean environment to avoid the influence of impurities on the film performance. Simultaneously, it is crucial to control the operating parameters of each step to ensure stable film quality.

[0051] The performance test results of the BOPET release film in the above embodiments and comparative examples are shown in Table 1: Table 1 It can be seen that the BOPET film prepared in Example 1 has excellent release properties, mechanical properties and optical properties. Example 2

[0052] This embodiment provides a method for preparing a release film, including the following steps: Step 1: Preparation of fluorosilicone release coating solution. A fluorosilicone release coating solution was prepared by combining 30 parts by weight of fluorosilicone release agent, 0.5 parts by weight of wetting agent, and 69.5 parts by weight of n-heptane.

[0053] The fluorosilicone release agent is prepared according to the following method: 13g of trifluoropropylcyclotrisiloxane (D3F), 9g of octamethylcyclotetrasiloxane (D4), 0.3g of tetramethyldihydrodisiloxane (TMDSO), and 2g of APTES / SiO2 nanoparticles were placed in a dry 100mL three-necked flask. The system was sealed and purged with nitrogen. The system was placed in an oil bath and heated to 75°C, and stirred for 30 min to maintain a constant temperature. Then, an appropriate amount of trifluoromethanesulfonic acid catalyst (5% of the total molar amount of monomers) was added, and the reaction was continued at 75°C for 8 h. After the reaction was completed, the system was allowed to cool completely, and n-heptane was added to dilute and neutralize the acid in the system. The solution was then filtered and distilled to remove the solvent. The solution was then subjected to reduced pressure at 180°C for 30 min to remove low-boiling-point molecules, yielding a fluorinated polysiloxane with terminal hydrogen. Take 2g of the synthesized hydrogen-terminated fluorinated polysiloxane and place it in a 100mL dry three-necked flask. Add excess vinyltrimethoxysilane, 5ppm Karstedt catalyst, and 5mL of solvent 1,3-bis(trifluoromethyl)benzene. Place the system in an oil bath with a condenser and heat to 80℃ for 10 hours. After the reaction is complete, remove the solvent by distillation at 116℃ to obtain the single-component fluorosilicone release agent.

[0054] Step 2: Preparation of the base film. Open-ended masterbatch and PET chips are mixed uniformly at a specific mass ratio to form the surface layer of the PET film's ABA structure. The masterbatch accounts for 75% of the surface layer's mass. The upper and lower surface layers have the same thickness and masterbatch proportion. The core layer is made of pure PET chips, with a core layer to surface layer thickness ratio of 1:9. The raw material melt is first extruded and cast, then the base film undergoes biaxial stretching and heat setting. The longitudinal stretching temperature is 85℃, with a stretching ratio of 3.2 times. The transverse stretching temperature is 110℃, with a stretching ratio of 3.5 times. The heat setting temperature is 210℃ for 10 seconds, ultimately yielding a 50-micron-thick base film.

[0055] Step 3: Online Coating: Coating is performed using a Gravure concave coating roller. An online coating station (including a corona treatment device and a coating device) is set between the longitudinal and transverse stretching of the BOPET film. After the PET film is corona-treated by the corona treatment device, the coating device evenly coats the PET surface with the coating liquid. Then, during the transverse stretching and heat setting process, it is cured and cross-linked, forming a release coating on the surface of the PET film, resulting in a BOPET film with a thickness of 50 micrometers, designated as Sample 3. Throughout the preparation process, it is necessary to maintain a clean environment to avoid the influence of impurities on the film performance. Simultaneously, it is crucial to control the operating parameters of each step to ensure stable film quality.

[0056] Comparative Example 2 This comparative example provides a method for preparing a release film, comprising the following steps: Step 1: Preparation of the fluorosilicone release coating solution. A fluorosilicone release coating solution was prepared by compounding 30 parts by weight of fluorosilicone release agent, 0.5 parts by weight of wetting agent, and 69.5 parts by weight of n-heptane. The fluorosilicone release agent was prepared according to the following method: 13g of trifluoropropylcyclotrisiloxane (D3F), 9g of octamethylcyclotetrasiloxane (D4), and 0.3g of tetramethyldihydrodisiloxane (TMDSO) were placed in a dry 100mL three-necked flask. The system was sealed and purged with nitrogen. The system was placed in an oil bath and heated to 75°C, and stirred for 30 min to maintain a constant temperature. Then, an appropriate amount of trifluoromethanesulfonic acid catalyst (5% of the total molar amount of monomers) was added, and the reaction was continued at 75°C for 8 h. After the reaction was completed, the system was allowed to cool completely, and n-heptane was added to dilute and neutralize the acid in the system. The mixture was then filtered and distilled to remove the solvent. The solution was then subjected to reduced pressure at 180°C for 30 min to remove low-boiling-point molecules, yielding a fluorinated polysiloxane with terminal hydrogen. 2g of the synthesized fluorinated polysiloxane with terminal hydrogen was placed in a dry 100mL three-necked flask, and excess vinyltrimethoxysilane, 5ppm Karstedt catalyst, and 5mL of 1,3-bis(trifluoromethyl)benzene solvent were added. The system was placed in an oil bath with a condenser installed, and the temperature was raised to 80°C for 10 hours. After the reaction was completed, the solvent was removed by distillation at 116°C to obtain the single-component fluorosilicone release agent.

[0057] Step 2: Preparation of the base film. Open-ended masterbatch and PET chips are mixed uniformly at a specific mass ratio to form the surface layer of the PET film's ABA structure. The masterbatch accounts for 75% of the surface layer's mass. The upper and lower surface layers have the same thickness and masterbatch proportion. The core layer is made of pure PET chips, with a core layer to surface layer thickness ratio of 1:9. The raw material melt is first extruded and cast, then the base film undergoes biaxial stretching and heat setting. The longitudinal stretching temperature is 85℃, with a stretching ratio of 3.2 times. The transverse stretching temperature is 110℃, with a stretching ratio of 3.5 times. The heat setting temperature is 210℃ for 10 seconds, ultimately yielding a 50-micron-thick base film.

[0058] Step 3: Online Coating: Coating is performed using a Gravure concave coating roller. An online coating station (including a corona treatment device and a coating device) is set between the longitudinal and transverse stretching of the BOPET film. After the PET film is corona-treated by the corona treatment device, the coating device evenly coats the PET surface with the coating liquid. Then, during the transverse stretching and heat setting process, it is cured and cross-linked, forming a release coating on the surface of the PET film, resulting in a BOPET film with a thickness of 50 micrometers, designated as Sample 4. Throughout the entire preparation process, it is necessary to maintain a clean environment to avoid the influence of impurities on the film performance. Simultaneously, it is crucial to control the operating parameters of each step to ensure stable film quality.

[0059] The performance test results of the BOPET release film in the above embodiments and comparative examples are shown in Table 2: Table 2 Example 3:

[0060] This embodiment provides a method for preparing a release film, including the following steps: Step 1: Preparation of fluorosilicone release coating solution. A fluorosilicone release coating solution was prepared by mixing 40 parts by weight of fluorosilicone release agent, 0.5 parts by weight of wetting agent, and 59.5 parts by weight of n-heptane.

[0061] The fluorosilicone release agent is prepared according to the following method: 14 g of trifluoropropylcyclotrisiloxane (D3F), 10 g of octamethylcyclotetrasiloxane (D4), 0.4 g of tetramethyldihydrodisiloxane (TMDSO), and 3 g of APTES / SiO2 nanoparticles were placed in a dry 100 mL three-necked flask. The system was sealed and purged with nitrogen. The system was placed in an oil bath and heated to 75 °C, and stirred for 30 min to maintain a constant temperature. Then, an appropriate amount of trifluoromethanesulfonic acid catalyst (5% of the total molar amount of monomers) was added, and the reaction was continued at 75 °C for 8 h. After the reaction was completed, the system was allowed to cool completely, and n-heptane was added to dilute and neutralize the acid in the system. The solution was then filtered and distilled to remove the solvent. The solution was then subjected to reduced pressure at 180 °C for 30 min to remove low-boiling-point molecules, yielding a fluorinated polysiloxane with terminal hydrogen. Take 2g of the synthesized hydrogen-terminated fluorinated polysiloxane and place it in a 100mL dry three-necked flask. Add excess vinyltrimethoxysilane, 5ppm Karstedt catalyst, and 5mL of solvent 1,3-bis(trifluoromethyl)benzene. Place the system in an oil bath with a condenser and heat to 80℃ for 10 hours. After the reaction is complete, remove the solvent by distillation at 116℃ to obtain the single-component fluorosilicone release agent.

[0062] Step 2: Preparation of the base film. Open-ended masterbatch and PET chips are mixed uniformly at a specific mass ratio to form the surface layer of the PET film's ABA structure. The masterbatch accounts for 60% of the surface layer's mass. The upper and lower surface layers have the same thickness and masterbatch proportion. The core layer is made of pure PET chips, with a core layer to surface layer thickness ratio of 1:9. The raw material melt is first extruded and cast, then the base film undergoes biaxial stretching and heat setting. The longitudinal stretching temperature is 100℃, with a stretching ratio of 3.5 times. The transverse stretching temperature is 120℃, with a stretching ratio of 4 times. The heat setting temperature is 230℃ for 20 seconds, ultimately yielding a 50-micron-thick base film.

[0063] Step 3: Online Coating: Coating is performed using a Gravure concave coating roller. An online coating station (including a corona treatment device and a coating device) is set between the longitudinal and transverse stretching of the BOPET film. After the PET film is corona-treated by the corona treatment device, the coating device evenly coats the PET surface with the coating liquid. Then, during the transverse stretching and heat setting process, it is cured and cross-linked, forming a release coating on the surface of the PET film, resulting in a BOPET film with a thickness of 50 micrometers, designated as Sample 5. Throughout the preparation process, it is necessary to maintain a clean environment to avoid the influence of impurities on the film performance. Simultaneously, it is crucial to control the operating parameters of each step to ensure stable film quality.

[0064] Comparative Example 3 This comparative example provides a method for preparing a release film, comprising the following steps: Step 1: Preparation of the fluorosilicone release coating solution. A fluorosilicone release coating solution was prepared by compounding 40 parts by weight of fluorosilicone release agent, 0.5 parts by weight of wetting agent, and 59.5 parts by weight of n-heptane. The fluorosilicone release agent was prepared according to the following method: 14 g of trifluoropropylcyclotrisiloxane (D3F), 10 g of octamethylcyclotetrasiloxane (D4), and 0.4 g of tetramethyldihydrodisiloxane (TMDSO) were placed in a dry 100 mL three-necked flask. The system was sealed and purged with nitrogen. The system was placed in an oil bath and heated to 75 °C, and stirred for 30 min to maintain a constant temperature. Then, an appropriate amount of trifluoromethanesulfonic acid catalyst (5% of the total molar amount of monomers) was added, and the reaction was continued at 75 °C for 8 h. After the reaction was completed, the system was allowed to cool completely, and n-heptane was added to dilute and neutralize the acid in the system. The mixture was then filtered and distilled to remove the solvent. The mixture was then subjected to reduced pressure at 180 °C for 30 min to remove low-boiling-point molecules, yielding a fluorinated polysiloxane with terminal hydrogen. 2 g of the synthesized fluorinated polysiloxane with terminal hydrogen was placed in a dry 100 mL three-necked flask, and excess vinyltrimethoxysilane, 5 ppm Karstedt catalyst, and 5 mL of 1,3-bis(trifluoromethyl)benzene solvent were added. The system was placed in an oil bath with a condenser installed, and the temperature was raised to 80°C for 10 hours. After the reaction was completed, the solvent was removed by distillation at 116°C to obtain the single-component fluorosilicone release agent.

[0065] Step 2: Preparation of the base film. Open-ended masterbatch and PET chips are mixed uniformly at a specific mass ratio to form the surface layer of the PET film's ABA structure. The masterbatch accounts for 60% of the surface layer's mass. The upper and lower surface layers have the same thickness and masterbatch proportion. The core layer is made of pure PET chips, with a core layer to surface layer thickness ratio of 1:9. The raw material melt is first extruded and cast, then the base film undergoes biaxial stretching and heat setting. The longitudinal stretching temperature is 100℃, with a stretching ratio of 3.5 times. The transverse stretching temperature is 120℃, with a stretching ratio of 4 times. The heat setting temperature is 230℃ for 20 seconds, ultimately yielding a 50-micron-thick base film.

[0066] Step 3: Online Coating: Coating is performed using a Gravure concave coating roller. An online coating station (including a corona treatment device and a coating device) is set between the longitudinal and transverse stretching of the BOPET film. After the PET film is corona-treated by the corona treatment device, the coating device evenly coats the PET surface with the coating liquid. Then, during the transverse stretching and heat setting process, it is cured and cross-linked, forming a release coating on the surface of the PET film, resulting in a BOPET film with a thickness of 50 micrometers, designated as Sample Six. Throughout the preparation process, it is necessary to maintain a clean environment to avoid the influence of impurities on the film performance. Simultaneously, it is crucial to control the operating parameters of each step to ensure stable film quality.

[0067] The performance test results of the BOPET release film in the above embodiments and comparative examples are shown in Table 3: Table 3 The performance testing methods for the BOPET release film in each embodiment and comparative example are as follows: Test methods for coating peel strength and residual adhesion: According to the test standard GB / T25256-2010 (refer to ISO29862), the 180° peel test is adopted.

[0068] Coating adhesion test: The adhesion between the PET substrate and the coating was tested according to ASTM D3359.

[0069] Tensile strength at break and elongation at break: tested according to ASTM D-882 standard.

[0070] Light transmittance: Tested according to ASTM D-1746 standard.

[0071] Haze: Tested according to ASTM D-1003 standard.

[0072] In summary, compared with existing technologies, the beneficial effects of this technical solution are as follows: 1. This invention prepares BOPET release films through coating modification, exhibiting excellent release performance and mechanical properties. 2. The fluorosilicone release coating agent prepared by this invention has good compatibility with PET, thereby ensuring the stability of the release coating and solving the technical problem in existing technologies where the peel strength of ordinary silicone oil coatings is affected by temperature and time, leading to a loss of peel stability. 3. The fluorosilicone release coating agent prepared by this invention is low in cost and simple to prepare, solving the problem that some existing release agents are expensive, thus limiting their application.

[0073] In summary, the BOPET release film prepared by this invention has significant advantages in release performance, mechanical properties and optical properties, and has high practical value and broad application prospects.

[0074] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for producing a fluorosilicon release agent, characterized by, The process includes the following steps: using fluorinated monomers, cyclic siloxanes, linear hydrogen-containing siloxanes, and nano-silica as raw materials, a cationic ring-opening polymerization reaction is carried out to prepare terminal hydrogen-containing fluorinated polysiloxanes; using the terminal hydrogen-containing fluorinated polysiloxanes and siloxanes with unsaturated bonds as raw materials, a hydrosilylation reaction is carried out to prepare a fluorosilicone release agent.

2. The method for preparing a fluorosilicon release agent according to claim 1, wherein The fluorine monomer is trifluoropropylcyclotrisiloxane.

3. The method for preparing the fluorosilicone release agent as described in claim 1, characterized in that, The cyclic siloxane is octamethylcyclotetrasiloxane.

4. The method for preparing the fluorosilicone release agent as described in claim 1, characterized in that, The linear hydrogen-containing siloxane is tetramethyldihydrodisiloxane.

5. The method for preparing the fluorosilicone release agent as described in claim 1, characterized in that, The nano-silica is APTES / SiO2 nanoparticles.

6. The method for preparing the fluorosilicone release agent as described in claim 1, characterized in that, The siloxane with unsaturated bonds is vinyltrimethoxysilane.

7. A fluorosilicone release agent, characterized in that, The fluorosilicone release agent is prepared by the method described in any one of claims 1-6.

8. A fluorosilicone release coating liquid, characterized in that, Includes the fluorosilicone release agent as described in claim 7.

9. The fluorosilicone release coating liquid as described in claim 8, characterized in that, Based on parts by weight, it includes the following components: 20-40 parts of the fluorosilicone release agent; Wetting agent 0.1-1.0 parts; 50-80 parts of n-heptane.

10. A release film, characterized in that, It includes a base film and a release layer disposed on the surface of the base film; the release layer is prepared by means of the fluorosilicone release coating liquid as described in claim 8 or 9.

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