Non-silicon release liquid and release film

Abstract

The application relates to the technical field of high polymer materials, in particular to a non-silicon release liquid and a release film, wherein the non-silicon release liquid comprises the following components in proportion by weight: a non-silicon release agent 18-36 parts; modified barium sulfate 2-4 parts; toluene 58.5-79.5 parts; a wetting agent 0.5-1.5 parts. The non-silicon release liquid provided by the application has excellent release performance through the synergistic effect among the components, and the non-silicon release agent can be combined with the PET base material through a chemical bond, so that the addition of the non-silicon release agent does not affect the mechanical properties of the film.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a non-silicone release liquid and 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] Currently, silicone, fluorine, and non-silicone (silicone-free and fluorine-free) release agents have been developed on the market. Among them, silicone release agents are the most widely used due to their low surface tension, excellent peel strength, and temperature resistance, offering a wide range of release forces. However, silicone materials tend to migrate to the surface of the substrate when incompletely cured, which not only leads to unstable release film peel strength but also contaminates the substrate, affecting the appearance of the release film and subsequent processing. In contrast, while fluorine-based release agents offer advantages such as low release force and good temperature resistance, their higher cost limits their application primarily to high-end products. Therefore, the market demand for non-silicone release agents has increased significantly, making the development of an economical non-silicone release agent that is free of silicone and fluorine and has high temperature resistance particularly important.

[0004] Existing non-silicone release agents are mainly comb-like polymers containing long alkyl side chains. Although these non-silicone release agents have the advantage of lower cost compared to fluorinated release agents, they have poor compatibility with BOPET substrates, which affects the mechanical properties of the film and limits the application of release films.

[0005] Therefore, how to impart good release properties to 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 non-silicone release agents in existing technologies can affect the mechanical properties of films, this invention provides a non-silicone release liquid. This non-silicone release liquid combines a non-silicone release agent with modified inorganic nanoparticles, which improves the release performance of the release film without affecting its mechanical properties, thus solving the problem of the addition of non-silicone release agents affecting the mechanical properties of films in existing technologies.

[0007] The technical solution adopted by this invention to solve its technical problem is: A non-silicone release liquid, comprising the following components by weight: 18-36 parts of non-silicone release agent; 2-4 parts of modified barium sulfate; Toluene 58.5-79.5 parts; 0.5-1.5 parts of wetting agent.

[0008] Optionally, the modified barium sulfate is prepared according to the following method: S1: Dissolve (3-aminopropyl)triethoxysilane in a mixture of ethanol and water according to the formula to obtain hydrolyzed APTES sol; S2: Disperse nano-BaSO4 in ethanol to obtain a dispersion; S3: Mix the dispersion with the hydrolyzed APTES sol, add acetic acid, and stir and reflux at 50-70°C to obtain modified barium sulfate.

[0009] Optionally, the volume ratio of ethanol to water in step S1 is 3:1.

[0010] Optionally, the ratio of (3-aminopropyl)triethoxysilane to the mixture in step S1 is 0.1 g: 10 mL.

[0011] Optionally, the ratio of nano-BaSO4 to ethanol in step S2 is 0.2g:10mL.

[0012] Optionally, the non-silicone release agent is prepared by a nucleophilic addition reaction of polyvinyl alcohol and octadecyl isocyanate.

[0013] Optionally, the wetting agent is a nonionic wetting agent.

[0014] 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 a non-silicone release liquid as described above.

[0015] The beneficial effects of this invention are: The non-silicone release liquid provided by this invention has excellent release properties through the synergistic effect between its components. At the same time, it enables the non-silicone release agent to be chemically bonded to the PET substrate, thus avoiding the impact of the addition of the non-silicone release agent on the mechanical properties of the film. Detailed Implementation

[0016] 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.

[0017] To address the problem that the addition of non-silicone release agents in existing technologies can affect the mechanical properties of films, this invention provides a non-silicone release liquid. The raw materials of this non-silicone release liquid, by weight, comprise the following components: 18-36 parts of non-silicone release agent; 2-4 parts of modified barium sulfate; Toluene 58.5-79.5 parts; 0.5-1.5 parts of wetting agent.

[0018] In this non-silicone release liquid, the non-silicone release agent is used to provide release performance. Preferably, the content of the non-silicone release agent is 18-36 parts by weight, so as to ensure release performance while avoiding cost increase and decreased adhesion to the base film due to excessive release agent content. Since the long alkyl side chains of existing non-silicone release agents are non-polar flexible segments, they have poor compatibility with the polar main chain of PET, which leads to the addition of existing non-silicone release agents affecting the mechanical properties of the film. Based on this, the present invention preferably introduces modified barium sulfate into the non-silicone release liquid. Barium sulfate itself has high hardness and thermal stability. After modification with APTES, the amino groups introduced on its surface can interact with the active groups in the non-silicone release agent, enhance the bonding force between barium sulfate and the release agent matrix, avoid nanoparticle agglomeration, and make it uniformly dispersed in the release layer to form a dense network structure.

[0019] The non-silicone release liquid provided by this invention enables the non-silicone release agent to be chemically bonded to the PET substrate through the synergistic effect between its components, thereby improving the release performance of the film while ensuring its mechanical properties.

[0020] Furthermore, the modified barium sulfate of the present invention is preferably prepared according to the following method: S1: Dissolve (3-aminopropyl)triethoxysilane (APTES) in a mixture of ethanol and water according to the formula to obtain hydrolyzed APTES sol. In this step, the ethoxy groups in the APTES molecules are gradually hydrolyzed into hydroxyl groups, forming a stable sol system. This process can control the degree of hydrolysis of APTES, avoiding molecular aggregation caused by excessive hydrolysis, and providing active sites for subsequent grafting reactions with inorganic nanoparticles. S2: Disperse nano-BaSO4 in ethanol to obtain a dispersion; Preferably, in this step, nano-BaSO4 is dispersed in ethanol by ultrasound. The dispersing effect of ethanol can make nano-BaSO4 uniformly dispersed in the solvent and avoid agglomeration. The uniformly dispersed nano-BaSO4 can fully contact the hydrolyzed APTES sol, ensuring the uniformity of the subsequent modification reaction. S3: Mix the dispersion with hydrolyzed APTES sol, add acetic acid, stir and reflux at 50-70℃ to obtain modified barium sulfate; In this step, acetic acid is used as a catalyst to adjust the pH of the reaction system, promoting the dehydration condensation reaction between the hydroxyl groups generated by the hydrolysis of APTES and the hydroxyl groups on the surface of nano BaSO4, thereby achieving the grafting of APTES molecules onto the surface of nano BaSO4; reflux operation is used to maintain a uniform temperature distribution in the reaction system, ensuring that all nanoparticles are fully modified. In a further preferred embodiment of the present invention, before modification, the nano-BaSO4 particles are placed in a vacuum oven at 75°C for 1 hour to remove adsorbed moisture; preferably, after the reflux reaction is completed, the resulting sol is centrifuged at 7000 rpm for 15 minutes, washed three times with an ethanol-distilled water mixture, and finally the APTES / nano-BaSO4 is dried in a vacuum oven at 75°C for 24 hours to obtain modified inorganic nanoparticles, namely modified barium sulfate.

[0021] The modified barium sulfate prepared by this invention has silane molecules containing amino groups uniformly grafted onto its surface. This not only improves the dispersibility of nano-BaSO4 in the organic phase, but also allows it to interact with the active groups in the non-silicone release agent and PET substrate. As a result, it enhances the bonding force between nano-BaSO4 and the release agent matrix, and also improves the bonding force between the non-silicone release agent and the PET substrate.

[0022] To ensure that APTES is fully hydrolyzed and forms a stable sol, the volume ratio of ethanol to water in step S1 of this invention is preferably 3:1.

[0023] Specifically, when the volume ratio of ethanol to water is too high, the water content is relatively insufficient, and the hydrolysis reaction of APTES cannot proceed fully, resulting in an insufficient number of active hydroxyl groups in the sol. This reduces the efficiency of the subsequent grafting reaction with nano-BaSO4, leading to poor modification effect of nano-BaSO4. Conversely, when the volume ratio is too low, the water content is too high, and the hydrolysis rate of APTES is too fast, making it prone to intermolecular self-aggregation reactions and forming large aggregates that cannot be uniformly grafted onto the surface of nanoparticles, which also affects the modification effect.

[0024] In a further preferred embodiment of the present invention, the ratio of (3-aminopropyl)triethoxysilane to the mixed solution in step S1 is 0.1 g: 10 mL, so as to achieve moderate modification of the surface of nano-BaSO4.

[0025] To achieve uniform dispersion of nano-BaSO4, the preferred ratio of nano-BaSO4 to ethanol in step S2 of this invention is 0.2g:10mL.

[0026] The refractive index of nano BaSO4 is similar to that of commonly used non-silicone release agent matrices such as polyvinyl alcohol. When added to the release layer, it does not produce obvious light scattering and can maintain the high transparency of the release film. Thus, it can improve the release performance without damaging the mechanical and optical properties of the release film.

[0027] Specifically, the preferred method for preparing APTES-modified nano-BaSO4 particles in this invention is as follows: 1-2 g of dried BaSO4 nanoparticles were ultrasonically dispersed in 30-50 mL of ethanol to obtain an ethanol solution containing the BaSO4 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 BaSO4 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℃ 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℃ vacuum oven for 24 hours to obtain APTES-modified BaSO4 nanoparticles.

[0028] The preferred non-silicone release agent of this invention is prepared by nucleophilic addition reaction of polyvinyl alcohol and octadecyl isocyanate.

[0029] Specifically, the preparation process can be carried out as follows: First, PVA powder is dried in a vacuum oven at 80-85℃ for 10-15 hours, while dimethyl sulfoxide and xylene are soaked in molecular sieves for more than 50 hours to remove residual moisture from the solvent. After the above pretreatment, 2-4 g of PVA, 15-25 mL of dimethyl sulfoxide, and 50-80 mL of xylene are added to a reaction flask and stirred. Then, 5-10 g of octadecyl isocyanate (ODI) is added. The reaction flask is sealed and nitrogen gas is introduced. The reaction is carried out in an oil bath at 75-80℃ for 3-5 hours. Then, 50-70 mL of isopropanol and 50-60 mL of methanol are added sequentially to precipitate the sample, which is then filtered. The precipitation is repeated three times with isopropanol and methanol at 50-60℃. Finally, the sample is dried at 40-50℃ for 8-10 hours to obtain a non-silicone release agent.

[0030] This invention allows for precise control of the hydrophobic group content in the release agent molecule by adjusting the reaction ratio of polyvinyl alcohol (PVA) and octadecyl isocyanate (OCI), thereby achieving flexible control over the release force. The long-chain alkyl groups in OCI possess strong hydrophobicity, forming a low surface energy layer on the release layer surface and imparting excellent release performance. Meanwhile, the hydroxyl groups in PVA interact with the active groups on the base film surface, enhancing the adhesion between the release layer and the base film. This non-silicone release agent is a polyurethane derivative, exhibiting good compatibility with organic solvents such as toluene, and can be uniformly dispersed in the release liquid, ensuring a continuous and uniform release layer after coating. Furthermore, it contains no silicone components, avoiding contamination problems caused by silicone migration, and has good compatibility with various protected materials, without affecting the subsequent processing performance of the protected materials. The polyurethane structure formed by the reaction of PVA and OCI possesses high thermal stability, maintaining a stable chemical structure at high temperatures and preventing release performance degradation. Compared to traditional polyethylene wax-based non-silicone release agents, its temperature resistance is significantly improved, meeting the requirements of high-temperature processing.

[0031] In addition, the preparation process of this non-silicone release agent is simple, the reaction conditions are mild, it is easy to industrialize, and the raw material cost is relatively low, making it economically viable.

[0032] Furthermore, the wetting agent of the present invention is preferably selected from at least one of TL-J20, TL-J40, and X-405.

[0033] The preferred non-silicone release liquid of the present invention is prepared by the following method: according to the formula amount, a non-silicone release agent, modified barium sulfate, toluene and wetting agent are compounded to prepare a non-silicone release liquid.

[0034] 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 a non-silicone release liquid as described above.

[0035] The release film provided by this invention, through the synergistic effect between the components of the non-silicone release liquid, enables the non-silicone release liquid to have excellent release performance. At the same time, it enables the non-silicone release agent to be chemically bonded to the PET substrate, avoiding the impact of the addition of the non-silicone release agent on the mechanical properties of the film. Thus, the release film has both excellent release performance and mechanical properties.

[0036] The release layer of this invention is preferably prepared by online coating. Specifically, the release film is preferably prepared according to the following method: S1: Preparation of the base film: The preferred base film of this invention has an ABA structure, and more preferably, the base film is prepared according to the following method: According to the formula, open-face masterbatch and PET chips are mixed evenly to form the ABA structure surface layer of the PET film. Preferably, the mass percentage of open-face masterbatch in the surface layer is 60-90%. The upper and lower surface layers have the same thickness and masterbatch proportion. The core layer is pure PET chips, and the core layer to surface layer thickness ratio is 1:9. The raw material melt is first extruded and cast, then the base film is subjected to biaxial stretching and heat setting. 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, finally obtaining the base film.

[0037] S2: Online coating: The coating is performed using a Gravure concave coating roller. An online coating station (including a corona device and a coating device) is set between the longitudinal and transverse stretching of BOPET. After the PET film is corona-treated by the corona device, the coating device evenly coats the PET surface with the coating liquid. Then, it is cured and cross-linked during transverse stretching and heat setting to form a release coating on the surface of the PET film, resulting in a BOPET film with a thickness of 50 micrometers.

[0038] S3: Post-processing: The BOPET film obtained in step S2 is cooled, wound up, and slit to obtain the final BOPET release film.

[0039] Throughout the preparation process, we need to maintain a clean environment to avoid impurities affecting the film performance, and at the same time, we need to control the operating parameters of each step to ensure the stability of the 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-modified BaSO4 nanoparticles in the embodiments and comparative examples of this invention were prepared according to the following method: 1.5 g of dried BaSO4 nanoparticles were ultrasonically dispersed in 40 mL of ethanol to obtain an ethanol solution containing the BaSO4 nanoparticles. 3 g of APTES was dissolved in 25 mL of a mixture containing ethanol and water at a volume ratio of 15:5 to prepare a hydrolyzed APTES sol. 10 mL of the ethanol solution containing the BaSO4 nanoparticles was taken, and 5 mL of the APTES sol was added. 3 mL of acetic acid was added as a catalyst, and the mixture was refluxed at 50-60°C and 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 vacuum oven at 75℃ for 24 hours to obtain APTES-modified BaSO4 nanoparticles. Example 1

[0043] This embodiment provides a method for preparing a release film, including the following steps: Step 1: Preparation of the release coating solution. A release coating solution was prepared by combining 18 parts by weight of a non-silicone release agent, 2 parts by weight of APTES-modified BaSO4 nanoparticles, 0.5 parts by weight of a wetting agent, and 79.5 parts by weight of toluene. The synthesis method of the non-silicone release agent is as follows: First, PVA powder was dried in a vacuum oven at 80°C for 15 hours, while dimethyl sulfoxide and xylene were soaked in molecular sieves for more than 50 hours to remove residual moisture from the solvent. After the above pretreatment, 2g of PVA, 15mL of dimethyl sulfoxide, and 50mL of xylene were added to a reaction flask and stirred vigorously. Then, 5g of octadecyl isocyanate (ODI) was added, the reaction flask was sealed, and nitrogen gas was introduced. The reaction was carried out in an oil bath at 75°C for 5 hours. Then, 50mL of isopropanol and 50mL of methanol were added sequentially to precipitate the sample, which was then filtered. The precipitation was repeated three times with isopropanol and methanol at 50°C. Finally, the sample was dried at 40°C for 10 hours to obtain a non-silicone release agent.

[0044] 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.

[0045] 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.

[0046] Comparative Example 1-1 This comparative example provides a method for preparing a release film, comprising the following steps: Step 1: Preparation of the release coating solution. According to the weight percentages, 20 parts of non-silicone release agent, 0.5 parts of wetting agent, and 79.5 parts of toluene are combined to prepare the release coating solution. The non-silicone release agent is prepared as follows: First, PVA powder was dried in a vacuum oven at 80°C for 15 hours, while dimethyl sulfoxide and xylene were soaked in molecular sieves for more than 50 hours to remove residual moisture from the solvent. After the above pretreatment, 2g of PVA, 15mL of dimethyl sulfoxide, and 50mL of xylene were added to a reaction flask and stirred vigorously. Then, 5g of octadecyl isocyanate (ODI) was added, the reaction flask was sealed, and nitrogen gas was introduced. The reaction was carried out in an oil bath at 75°C for 5 hours. Then, 50mL of isopropanol and 50mL of methanol were added sequentially to precipitate the sample, which was then filtered. The precipitation was repeated three times with isopropanol and methanol at 50°C. Finally, the sample was dried at 40°C for 10 hours to obtain a non-silicone release agent.

[0047] 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.

[0048] 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.

[0049] Comparative Examples 1-2 This comparative example provides a method for preparing a release film, comprising the following steps: Step 1: Preparation of the release coating solution. A release coating solution was prepared by mixing 18 parts by weight of a non-silicone release agent, 2 parts by weight of nano-BaSO4 particles, 0.5 parts by weight of a wetting agent, and 79.5 parts by weight of toluene. The synthesis method of the non-silicone release agent is as follows: First, PVA powder was dried in a vacuum oven at 80°C for 15 hours, while dimethyl sulfoxide and xylene were soaked in molecular sieves for more than 50 hours to remove residual moisture from the solvent. After the above pretreatment, 2g of PVA, 15mL of dimethyl sulfoxide, and 50mL of xylene were added to a reaction flask and stirred vigorously. Then, 5g of octadecyl isocyanate (ODI) was added, the reaction flask was sealed, and nitrogen gas was introduced. The reaction was carried out in an oil bath at 75°C for 5 hours. Then, 50mL of isopropanol and 50mL of methanol were added sequentially to precipitate the sample, which was then filtered. The precipitation was repeated three times with isopropanol and methanol at 50°C. Finally, the sample was dried at 40°C for 10 hours to obtain a non-silicone release agent.

[0050] 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.

[0051] 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.

[0052] The performance test results of the BOPET release film in the above embodiments and comparative examples are shown in Table 1: Table 1 Example 2

[0053] This embodiment provides a method for preparing a release film, including the following steps: Step 1: Preparation of the release coating solution. A release coating solution was prepared by mixing 27 parts by weight of a non-silicone release agent, 3 parts by weight of APTES-modified BaSO4 nanoparticles, 1 part by weight of a wetting agent, and 69 parts by weight of toluene. The non-silicone release agent was prepared according to the following method: First, PVA powder was dried in a vacuum oven at 85°C for 10 hours, while dimethyl sulfoxide and xylene were soaked in molecular sieves for more than 50 hours to remove residual moisture from the solvent. After the above pretreatment, 3g PVA, 20mL dimethyl sulfoxide, and 65mL xylene were added to a reaction flask and stirred vigorously. Then, 7.5g octadecyl isocyanate (ODI) was added, the reaction flask was sealed, and nitrogen gas was introduced. The reaction was carried out in an oil bath at 80°C for 3 hours. Then, 60mL isopropanol and 55mL methanol were added sequentially to precipitate the sample, which was then filtered. The precipitation was repeated three times with isopropanol and methanol at 60°C. Finally, the sample was dried at 50°C for 8 hours to obtain a non-silicone 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 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.

[0056] Comparative Example 2 This comparative example provides a method for preparing a release film, comprising the following steps: Step 1: Preparation of the release coating solution. A release coating solution was prepared by mixing 30 parts by weight of a non-silicone release agent, 1 part by weight of a wetting agent, and 69 parts by weight of toluene. The non-silicone release agent was prepared according to the following method: First, PVA powder was dried in a vacuum oven at 85°C for 10 hours, while dimethyl sulfoxide and xylene were soaked in molecular sieves for more than 50 hours to remove residual moisture from the solvent. After the above pretreatment, 3g PVA, 20mL dimethyl sulfoxide, and 65mL xylene were added to a reaction flask and stirred vigorously. Then, 7.5g octadecyl isocyanate (ODI) was added, the reaction flask was sealed, and nitrogen gas was introduced. The reaction was carried out in an oil bath at 80°C for 3 hours. Then, 60mL isopropanol and 55mL methanol were added sequentially to precipitate the sample, which was then filtered. The precipitation was repeated three times with isopropanol and methanol at 60°C. Finally, the sample was dried at 50°C for 8 hours to obtain a non-silicone 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 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.

[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 the release coating solution. A release coating solution was prepared by mixing 36 parts by weight of a non-silicone release agent, 4 parts by weight of APTES-modified BaSO4 nanoparticles, 1.5 parts by weight of a wetting agent, and 58.5 parts by weight of toluene. The non-silicone release agent was prepared according to the following method: First, PVA powder was dried in a vacuum oven at 80°C for 15 hours, while dimethyl sulfoxide and xylene were soaked in molecular sieves for more than 50 hours to remove residual moisture from the solvent. After the above pretreatment, 4g PVA, 25mL dimethyl sulfoxide, and 80mL xylene were added to a reaction flask and stirred vigorously. Then, 10g octadecyl isocyanate (ODI) was added, the reaction flask was sealed, and nitrogen gas was introduced. The reaction was carried out in an oil bath at 80°C for 3 hours. Then, 70mL isopropanol and 60mL methanol were added sequentially to precipitate the sample, which was then filtered. The precipitation was repeated three times with isopropanol and methanol at 60°C. Finally, the sample was dried at 50°C for 8 hours to obtain a non-silicone release agent.

[0061] 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.

[0062] Step 3: Online Coating: Coating is performed using a Gravure concave coating roller. An online coating station (including a corona discharge 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 discharge device, the coating device evenly coats the PET surface with the coating liquid. Then, during transverse stretching and heat setting, 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.

[0063] Comparative Example 3 This comparative example provides a method for preparing a release film, comprising the following steps: Step 1: Preparation of the release coating solution. A release coating solution was prepared by compounding 40 parts by weight of non-silicone release agent, 1.5 parts by weight of wetting agent, and 58.5 parts by weight of toluene. The non-silicone release agent was prepared according to the following method: First, PVA powder was dried in a vacuum oven at 80°C for 15 hours, while dimethyl sulfoxide and xylene were soaked in molecular sieves for more than 50 hours to remove residual moisture from the solvent. After the above pretreatment, 4g PVA, 25mL dimethyl sulfoxide, and 80mL xylene were added to a reaction flask and stirred vigorously. Then, 10g octadecyl isocyanate (ODI) was added, the reaction flask was sealed, and nitrogen gas was introduced. The reaction was carried out in an oil bath at 80°C for 3 hours. Then, 70mL isopropanol and 60mL methanol were added sequentially to precipitate the sample, which was then filtered. The precipitation was repeated three times with isopropanol and methanol at 60°C. Finally, the sample was dried at 50°C for 8 hours to obtain a non-silicone release agent.

[0064] 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.

[0065] 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 transverse stretching and heat setting, it is cured and cross-linked, forming a release coating on the surface of the PET film, resulting in a 50-micron-thick BOPET film, designated as Sample Seven. 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.

[0066] 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 BOPET release films in the embodiments and comparative examples of this invention 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.

[0067] Coating adhesion test: The adhesion between the PET substrate and the coating was tested according to ASTM D3359.

[0068] Tensile strength at break and elongation at break: tested according to ASTM D-882 standard.

[0069] Light transmittance: Tested according to ASTM D-1746 standard.

[0070] Haze: Tested according to ASTM D-1003 standard.

[0071] As can be seen from the data in the tables above, the BOPET films prepared in the various embodiments of the present invention have excellent release properties, mechanical properties and optical properties.

[0072] 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 non-silicone release liquid, characterized in that, Based on parts by weight, it includes the following components: 18-36 parts of non-silicone release agent; 2-4 parts of modified barium sulfate; Toluene 58.5-79.5 parts; 0.5-1.5 parts of wetting agent.

2. The non-silicone release liquid as described in claim 1, characterized in that, The modified barium sulfate is prepared according to the following method: S1: Dissolve (3-aminopropyl)triethoxysilane in a mixture of ethanol and water according to the formula to obtain hydrolyzed APTES sol; S2: Disperse nano-BaSO4 in ethanol to obtain a dispersion; S3: Mix the dispersion with the hydrolyzed APTES sol, add acetic acid, and stir and reflux at 50-70°C to obtain modified barium sulfate.

3. The non-silicone release liquid as described in claim 2, characterized in that, The volume ratio of ethanol to water in step S1 is 3:

1.

4. The non-silicone release liquid as described in claim 2, characterized in that, The ratio of (3-aminopropyl)triethoxysilane to the mixture in step S1 is 0.1 g: 10 mL.

5. The non-silicone release liquid as described in claim 2, characterized in that, In step S2, the ratio of nano-BaSO4 to ethanol is 0.2g:10mL.

6. The non-silicone release liquid according to any one of claims 1-5, characterized in that, The non-silicone release agent is prepared by a nucleophilic addition reaction of polyvinyl alcohol and octadecyl isocyanate.

7. The non-silicone release liquid according to any one of claims 1-5, characterized in that, The wetting agent is a nonionic wetting agent.

8. 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 a non-silicone release liquid as described in any one of claims 1-7.

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