A high adhesion strength tac film and a method of making the same

Abstract

This invention discloses a high-adhesion-strength TAC film and its preparation method, belonging to the field of polymer protective film technology. The preparation method includes the following steps: mixing cellulose triacetate, a stabilizer, a plasticizer, a UV stabilizer, and a solvent, dissolving them under heating and stirring conditions to form a homogeneous TAC solution, and obtaining a TAC base film through casting and drying; subjecting the TAC base film to low-temperature plasma treatment, and then drying it at a temperature of 80-100℃ to obtain a high-adhesion-strength TAC film; the stabilizer is phenylboronic acid-terminated cellulose acetate. This invention provides a high-adhesion-strength TAC film and its preparation method. Through the synergistic effect of low-temperature plasma surface activation and phenylboronic acid-terminated cellulose acetate stabilizer, the surface adhesion performance of the TAC film is significantly improved while effectively solving the problem of decreased mechanical properties caused by plasma treatment, achieving a balance between high adhesion strength and excellent mechanical properties.

Description

Technical Field

[0001] This invention belongs to the field of polymer protective film technology, specifically relating to a high-adhesion-strength TAC film and its preparation method. Background Technology

[0002] Triacetyl cellulose film (TAC film) is an optical functional film made from natural cellulose through an acetylation reaction to obtain triacetyl cellulose ester, which is then formed using a solution casting process. The film thickness is typically controlled within the range of 40 to 100 micrometers, with a visible light transmittance exceeding 90%, while also possessing excellent optical uniformity, low birefringence, and good dimensional stability. Based on these characteristics, TAC film has become a core substrate for polarizers in liquid crystal display devices, and its optical quality and mechanical properties directly affect the performance of the polarizer and the final display device.

[0003] A typical polarizer structure consists of a polyvinyl alcohol (PVA) polarizing layer and multiple layers of TAC protective films on both sides, bonded together with an adhesive. However, the TAC film molecular chain is rich in acetate groups, exhibiting a hydrophobic surface. This results in poor interfacial compatibility with hydrophilic PVA films or commonly used adhesives, easily leading to defects such as interfacial peeling and bubbles during direct bonding, making it difficult to meet the structural integrity requirements of the laminate. Therefore, existing technologies commonly employ saponification to modify the surface of the TAC film. Saponification involves immersing the TAC film in an alkaline solution (such as sodium hydroxide or potassium hydroxide aqueous solution), causing the alkaline solution to hydrolyze the ester groups on the film surface, converting some acetate groups into hydroxyl groups. This reaction transforms the TAC film surface from hydrophobic to hydrophilic, and the resulting hydroxyl groups, as polar groups, can form hydrogen bonds or stronger chemical bonds with polar groups on the adhesive or PVA film surface, thereby significantly improving interfacial adhesion strength.

[0004] Although saponification can improve the surface adhesion of TAC films to some extent, existing technologies still have many shortcomings. For example, the uniformity and controllability of the saponification reaction are insufficient. Existing technologies mostly use inorganic strong alkali systems, and the effect of the alkali solution on the TAC film surface is often limited to an extremely thin layer. Moreover, the degree of reaction is affected by multiple factors such as alkali concentration, temperature, and treatment time, which can easily lead to localized over-hydrolysis or incomplete reaction. Over-hydrolysis leads to surface deterioration of the TAC film, producing microcracks or hazy whitening, which impairs optical properties; insufficient reaction fails to form enough active hydroxyl groups, resulting in limited improvement in adhesion strength.

[0005] Meanwhile, achieving both good adhesion and environmental stability is challenging. While the large number of hydroxyl groups introduced by saponification enhances surface hydrophilicity, it also significantly increases the hygroscopicity of the TAC film. In high-humidity environments, the film is prone to swelling and deformation, causing polarizer warping or interfacial stress concentration. Simultaneously, surface hydroxyl groups may undergo re-esterification or activity decay during humid heat aging, leading to decreased long-term adhesion reliability. Furthermore, there is a trade-off between mechanical properties and adhesion performance. TAC films are inherently brittle polymers with low elongation at break, making them prone to breakage during manufacturing. Existing technologies often require increasing the degree of saponification to obtain sufficient interfacial adhesion strength, but this further weakens the film's mechanical properties, resulting in decreased tensile strength and toughness, making it difficult to meet the flexibility requirements of high-performance polarized eyeglass lenses during heat bending processes.

[0006] Existing technologies involve coating the TAC film surface with a coupling agent layer, introducing polar groups through plasma treatment, or adjusting the adhesive formulation to suit the saponified surface. However, these methods either increase the number of process steps and production costs, or suffer from problems such as uneven treatment effects, poor efficiency, and difficulty in balancing curing speed and optical compatibility.

[0007] In summary, existing TAC film technologies still suffer from drawbacks in terms of adhesion performance, including poor reaction controllability, insufficient environmental stability, loss of mechanical properties, and limited process adaptability. These limitations make it difficult to simultaneously meet the comprehensive requirements of high adhesion strength, excellent optical performance, good mechanical toughness, and long-term reliability. How to effectively improve and stably control interfacial adhesion performance while maintaining the bulk properties of the TAC film remains a pressing technical challenge in this field. Summary of the Invention

[0008] The purpose of this invention is to provide a TAC film with high bonding strength and its preparation method, so as to solve the problem of insufficient bonding strength of TAC film.

[0009] The objective of this invention can be achieved through the following technical solutions: The first aspect of this invention provides a method for preparing a TAC film with high bonding strength, comprising the following steps: Cellulose triacetate, stabilizer, plasticizer, UV stabilizer, and solvent are mixed and dissolved under heating and stirring conditions to form a uniform TAC solution. The solution is extruded through a casting nozzle and cast onto a continuously operating substrate. After peeling, drying, trimming, and winding, a TAC base film is obtained. The TAC base film is then subjected to low-temperature plasma treatment and then constant-temperature treatment at 80-100℃ for 2-4 hours to obtain a TAC film with high bonding strength. The stabilizer is cellulose acetate capped with phenylboronic acid.

[0010] Furthermore, the conditions for low-temperature plasma treatment are: pressure 0.1-0.4 MPa, plasma treatment time 4-8 min.

[0011] Furthermore, the low-temperature plasma in the low-temperature plasma treatment is one of oxygen low-temperature plasma and nitrogen low-temperature plasma; the corresponding treatment gases are oxygen and nitrogen, respectively, with a gas flow rate of 20 mL / min and a discharge power of 100 W.

[0012] Furthermore, the mass ratio of cellulose triacetate, plasticizer, and UV stabilizer is 90-95:5-10:1-3; the solid content of the TAC solution is 10%-20%; and the amount of stabilizer added is 4%-7% of the mass of cellulose triacetate.

[0013] Furthermore, the plasticizer is at least one of sucrose benzoate and tributyl citrate; sucrose benzoate has multiple benzoate groups, exhibits excellent compatibility with TAC, and its rigid sugar ring structure can inhibit over-plasticization and maintain film stiffness; the triester groups of tributyl citrate provide efficient plasticization and outstanding low-temperature toughness, while the flexibility of its butyl chain promotes molecular chain segment movement during borate bond rearrangement. The synergistic use of both can improve the flexibility and processing adaptability of the film without significantly reducing the glass transition temperature, and reduce the risk of brittle fracture during hot pressing and bending.

[0014] The solvent is at least one of acetone, dichloromethane, and methanol; The UV stabilizer is a benzotriazole UV absorber, such as at least one of 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2,4-di-tert-butyl-6-(5-chlorobenzotriazole-2-yl)phenol, and 2-(2'-hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole. The phenolic hydroxyl group of benzotriazole forms a weak hydrogen bond with phenylboronic acid, which can improve the uniformity of the stabilizer's dispersion in the TAC matrix.

[0015] Furthermore, the stabilizer is prepared by the following steps: Cellulose diacetate and an aminosilane coupling agent were added to a solvent (n-butanol), followed by the addition of the aminosilane coupling agent. The mixture was heated under reflux for 18-30 hours to obtain aminosilane-modified cellulose acetate. This stabilizer uses cellulose diacetate as a raw material, introducing amino groups through a silane coupling agent reaction, followed by a Schiff base reaction with formylphenylboronic acid containing aldehyde groups, ultimately yielding phenylboronic acid-terminated cellulose acetate. Because phenylboronic acid-terminated cellulose acetate has a structure similar to cellulose triacetate, it exhibits good dispersibility and can be uniformly distributed in TAC-based membranes, avoiding increased haze and mechanical defects caused by phase separation, and ensuring a continuous and effective distribution of active sites within the dynamic repair network.

[0016] Furthermore, the introduced dynamic borate ester network allows for local rearrangement. The transient dissociation of borate ester bonds during hot pressing provides relaxation time for polymer chain segments, and microbubbles migrate to the edge and are discharged under the drive of the pressure gradient, which can reduce the haze of the product.

[0017] Aminosilane coupling agent-modified cellulose acetate and formylphenylboronic acid were added to methanol and stirred at room temperature for 12-16 hours. The methanol was then removed by vacuum concentration to obtain the stabilizer.

[0018] Furthermore, the mass ratio of cellulose diacetate to aminosilane coupling agent is 1:2-3; the volume ratio of cellulose diacetate to solvent is 1g:150-200mL; and the mass ratio of aminosilane coupling agent-modified cellulose acetate to formylphenylboronic acid is 2:0.8-0.9.

[0019] Furthermore, the formylphenylboronic acid is one of o-formylphenylboronic acid, m-formylphenylboronic acid, and p-formylphenylboronic acid.

[0020] Furthermore, the solvent is n-butanol; the acetic acid content of cellulose diacetate is 53%–56%; The aminosilane coupling agent is one of γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, and γ-aminopropylmethyldiethoxysilane.

[0021] A second aspect of the present invention provides a TAC film with high bonding strength, which is prepared by the above-described preparation method.

[0022] The beneficial effects of this invention are: This invention provides a high-bonding-strength TAC film and its preparation method. Through the synergistic effect of low-temperature plasma surface activation and phenylboronic acid-terminated cellulose acetate stabilizer, the surface bonding performance of the TAC film is significantly improved while effectively solving the problem of decreased mechanical properties caused by plasma treatment, thus achieving a balance between high bonding strength and excellent mechanical properties.

[0023] This invention first employs low-temperature plasma treatment to the TAC-based film. On one hand, this introduces polar functional groups such as hydroxyl, carboxyl, and amino groups onto the TAC film surface, significantly increasing surface energy and improving the film's wettability and adhesive spreading ability, thereby enhancing the bonding strength between the TAC film and interlayers such as polarizers and protective films. On the other hand, it removes surface contaminants and increases the density of surface active sites. However, while plasma treatment activates the surface, it also causes free radicals in the polymer to initiate chain cleavage reactions, resulting in some damage to the TAC-based film surface and a decrease in the film's mechanical properties.

[0024] To address this issue, this invention incorporates phenylboronic acid-terminated cellulose acetate as a stabilizer during the TAC membrane preparation process. The phenylboronic acid structure in this stabilizer exhibits dynamic response characteristics during subsequent use. Under isothermal treatment at 80-100°C, the borate ester bonds undergo network rearrangement via transesterification. This topological rearrangement completely releases residual internal stress generated during hot pressing, preventing interfacial damage or membrane warping caused by stress concentration. It also repairs polymer chain breakage caused by plasma treatment and, through dynamic bond exchange, enhances the mechanical properties and interfacial adhesion strength of the TAC membrane. Detailed Implementation

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0026] Obviously, the following description is merely some examples or embodiments of this application. Those skilled in the art can apply this application to other similar scenarios without any inventive effort. Furthermore, it is understood that although the effort involved in such development may be complex and lengthy, for those skilled in the art related to the content disclosed in this application, any changes to design, manufacturing, or production based on the technical content disclosed in this application are merely conventional technical means and should not be construed as insufficient disclosure of the content of this application.

[0027] However, there may be instances where unnecessary detailed descriptions are omitted. For example, detailed descriptions of well-known matters or repetitive descriptions of essentially the same structure may be omitted. This is to avoid making the following description unnecessarily lengthy and to facilitate understanding by those skilled in the art. Furthermore, the following description is provided to enable those skilled in the art to fully understand this application and is not intended to limit the subject matter of the claims.

[0028] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions, and all technical features and optional technical features of this application can be combined to form new technical solutions.

[0029] The following is a detailed description of a high-adhesion-strength TAC film and its preparation method according to an embodiment of this application.

[0030] The following is a detailed description with reference to specific examples.

[0031] Example 1 This embodiment provides a method for preparing a TAC film with high bonding strength, comprising the following steps: Cellulose triacetate, stabilizer, plasticizer, UV stabilizer, and solvent are mixed and dissolved under heating and stirring to form a homogeneous TAC solution. This solution is extruded through a casting nozzle and cast onto a continuously operating substrate. After peeling, drying, edge trimming, and winding, a TAC base film is obtained. The mass ratio of cellulose triacetate, plasticizer, and UV stabilizer is 90:5:1; the solid content of the TAC solution is 15%; and the amount of stabilizer added is 5% of the mass of cellulose triacetate. The solvent is a mixture of dichloromethane and methanol in equal volumes; the UV stabilizer is 2-(2'-hydroxy-3',5'-dipentylphenyl)benzotriazole; the plasticizer is sucrose benzoate and tributyl citrate, with a mass ratio of 2:1. The TAC-based membrane was subjected to low-temperature plasma treatment with oxygen as the treatment gas, a gas flow rate of 20 mL / min, a discharge power of 100 W, a pressure of 0.2 MPa, and a plasma treatment time of 5 min. Then, it was kept at a constant temperature of 80 °C for 4 h to obtain a TAC membrane with high bonding strength.

[0032] The stabilizer is prepared through the following steps: Cellulose diacetate and an aminosilane coupling agent were added to n-butanol, followed by the addition of the aminosilane coupling agent. The mixture was heated under reflux for 24 hours to obtain cellulose acetate modified with the aminosilane coupling agent.

[0033] Aminosilane coupling agent-modified cellulose acetate and formylphenylboronic acid were added to methanol and stirred at room temperature for 12 hours. The methanol was then removed by vacuum concentration to obtain the stabilizer. The mass ratio of cellulose diacetate to aminosilane coupling agent was 1:2; the mass ratio of cellulose diacetate to n-butanol was 1 g:150 mL; and the mass ratio of aminosilane coupling agent-modified cellulose acetate to formylphenylboronic acid was 2:0.8. The formylphenylboronic acid was o-formylphenylboronic acid; the aminosilane coupling agent was γ-aminopropyltriethoxysilane.

[0034] Example 2 This embodiment provides a method for preparing a TAC film with high bonding strength, comprising the following steps: Cellulose triacetate, stabilizer, plasticizer, UV stabilizer, and solvent are mixed and dissolved under heating and stirring to form a homogeneous TAC solution. This solution is extruded through a casting nozzle and cast onto a continuously operating substrate. After peeling, drying, edge trimming, and winding, a TAC base film is obtained. The mass ratio of cellulose triacetate, plasticizer, and UV stabilizer is 90:8:2; the solid content of the TAC solution is 15%; and the amount of stabilizer added is 6% of the mass of cellulose triacetate. The solvent is a mixture of dichloromethane and methanol in equal volumes; the UV stabilizer is 2-(2'-hydroxy-3',5'-dipentylphenyl)benzotriazole; the plasticizer is sucrose benzoate and tributyl citrate, with a mass ratio of 2:1. The TAC-based membrane was subjected to low-temperature plasma treatment with oxygen as the treatment gas, a gas flow rate of 20 mL / min, a discharge power of 100 W, a pressure of 0.3 MPa, and a plasma treatment time of 6 min. Then, it was kept at a constant temperature of 100 °C for 2 h to obtain a TAC membrane with high bonding strength.

[0035] The stabilizer used is the same as in Example 1.

[0036] Example 3 This embodiment provides a method for preparing a TAC film with high bonding strength, comprising the following steps: Cellulose triacetate, stabilizer, plasticizer, UV stabilizer, and solvent are mixed and dissolved under heating and stirring to form a homogeneous TAC solution. This solution is extruded through a casting nozzle and cast onto a continuously operating substrate. After peeling, drying, edge trimming, and winding, a TAC base film is obtained. The mass ratio of cellulose triacetate, plasticizer, and UV stabilizer is 95:10:3; the solid content of the TAC solution is 15%; and the amount of stabilizer added is 5% of the mass of cellulose triacetate. The solvent is a mixture of dichloromethane and methanol in equal volumes; the UV stabilizer is 2-(2'-hydroxy-3',5'-dipentylphenyl)benzotriazole; the plasticizer is sucrose benzoate and tributyl citrate, with a mass ratio of 2:1. The TAC-based membrane was subjected to low-temperature plasma treatment with oxygen as the treatment gas, a gas flow rate of 20 mL / min, a discharge power of 100 W, a pressure of 0.2 MPa, and a plasma treatment time of 5 min. Then, it was kept at a constant temperature of 100 °C for 2 h to obtain a TAC membrane with high bonding strength.

[0037] The stabilizer used is the same as in Example 1.

[0038] Example 4 This embodiment provides a method for preparing a TAC film with high bonding strength, comprising the following steps: Cellulose triacetate, stabilizer, plasticizer, UV stabilizer, and solvent are mixed and dissolved under heating and stirring to form a homogeneous TAC solution. This solution is extruded through a casting nozzle and cast onto a continuously operating substrate. After peeling, drying, edge trimming, and winding, a TAC base film is obtained. The mass ratio of cellulose triacetate, plasticizer, and UV stabilizer is 90:5:1; the solid content of the TAC solution is 15%; and the amount of stabilizer added is 7% of the mass of cellulose triacetate. The solvent is a mixture of dichloromethane and methanol in equal volumes; the UV stabilizer is 2-(2'-hydroxy-3',5'-dipentylphenyl)benzotriazole; the plasticizer is sucrose benzoate and tributyl citrate, with a mass ratio of 2:1. The TAC-based membrane was subjected to low-temperature plasma treatment with oxygen as the treatment gas, a gas flow rate of 20 mL / min, a discharge power of 100 W, a pressure of 0.2 MPa, and a plasma treatment time of 5 min. Then, it was kept at a constant temperature of 100 °C for 2 h to obtain a TAC membrane with high bonding strength.

[0039] The stabilizer used is the same as in Example 1.

[0040] Example 5 This embodiment provides a method for preparing a TAC film with high bonding strength, comprising the following steps: Cellulose triacetate, stabilizer, plasticizer, UV stabilizer, and solvent are mixed and dissolved under heating and stirring to form a homogeneous TAC solution. This solution is extruded through a casting nozzle and cast onto a continuously operating substrate. After peeling, drying, edge trimming, and winding, a TAC base film is obtained. The mass ratio of cellulose triacetate, plasticizer, and UV stabilizer is 90:5:1; the solid content of the TAC solution is 15%; and the amount of stabilizer added is 5% of the mass of cellulose triacetate. The solvent is a mixture of dichloromethane and methanol in equal volumes; the UV stabilizer is 2-(2'-hydroxy-3',5'-dipentylphenyl)benzotriazole; the plasticizer is sucrose benzoate and tributyl citrate, with a mass ratio of 2:1. The TAC-based membrane was subjected to low-temperature plasma treatment with oxygen as the treatment gas, a gas flow rate of 20 mL / min, a discharge power of 100 W, a pressure of 0.2 MPa, and a plasma treatment time of 8 min. Then, it was kept at a constant temperature of 80 °C for 4 h to obtain a TAC membrane with high bonding strength.

[0041] The stabilizer used is the same as in Example 1.

[0042] Example 6 The difference between this embodiment and Example 1 is that the stabilizer is different, and it is prepared through the following steps: Cellulose diacetate and an aminosilane coupling agent were added to n-butanol, followed by the addition of the aminosilane coupling agent. The mixture was heated under reflux for 24 hours to obtain cellulose acetate modified with the aminosilane coupling agent.

[0043] Aminosilane coupling agent-modified cellulose acetate and formylphenylboronic acid were added to methanol and stirred at room temperature for 12 hours. The methanol was then removed by vacuum concentration to obtain the stabilizer. The mass ratio of cellulose diacetate to aminosilane coupling agent was 1:2; the mass ratio of cellulose diacetate to n-butanol was 1 g:150 mL; and the mass ratio of aminosilane coupling agent-modified cellulose acetate to formylphenylboronic acid was 2:0.8. The formylphenylboronic acid was m-formylphenylboronic acid; the aminosilane coupling agent was γ-aminopropyltriethoxysilane.

[0044] The remaining raw materials and preparation process are the same as in Example 1.

[0045] Example 7 The difference between this embodiment and Example 1 is that the stabilizer is different, and it is prepared through the following steps: Cellulose diacetate and an aminosilane coupling agent were added to n-butanol, followed by the addition of the aminosilane coupling agent. The mixture was heated under reflux for 24 hours to obtain cellulose acetate modified with the aminosilane coupling agent.

[0046] Cellulose acetate modified with aminosilane coupling agent and formylphenylboronic acid were added to methanol and stirred at room temperature for 12 hours. The methanol was then removed by vacuum concentration to obtain the stabilizer. The mass ratio of cellulose diacetate to aminosilane coupling agent was 1:2; the mass ratio of cellulose diacetate to n-butanol was 1 g:150 mL; and the mass ratio of aminosilane coupling agent-modified cellulose acetate to formylphenylboronic acid was 2:0.8. The formylphenylboronic acid was p-formylphenylboronic acid; the aminosilane coupling agent was γ-aminopropyltriethoxysilane.

[0047] The remaining raw materials and preparation process are the same as in Example 1.

[0048] Example 8 The difference between this embodiment and Example 1 is that the stabilizer is different, and it is prepared through the following steps: Cellulose diacetate and an aminosilane coupling agent were added to n-butanol, followed by the addition of the aminosilane coupling agent. The mixture was heated under reflux for 24 hours to obtain cellulose acetate modified with the aminosilane coupling agent.

[0049] Aminosilane coupling agent-modified cellulose acetate and formylphenylboronic acid were added to methanol and stirred at room temperature for 12 hours. The methanol was then removed by vacuum concentration to obtain the stabilizer. The mass ratio of cellulose diacetate to aminosilane coupling agent was 1:3; the mass ratio of cellulose diacetate to n-butanol was 1 g:150 mL; and the mass ratio of aminosilane coupling agent-modified cellulose acetate to formylphenylboronic acid was 2:0.8. The formylphenylboronic acid was o-formylphenylboronic acid; the aminosilane coupling agent was N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane.

[0050] The remaining raw materials and preparation process are the same as in Example 1.

[0051] Comparative Example 1 The difference between this comparative example and Example 1 is that no stabilizer was added, while the other raw materials and preparation process remained the same as in Example 1.

[0052] Comparative Example 2 The difference between this comparative study and Example 1 is that low-temperature plasma treatment is not performed, while the other raw materials and preparation process remain the same as in Example 1.

[0053] Comparative Example 3 The difference between this comparative example and Example 1 is that no stabilizer is added and no low-temperature plasma treatment is performed, while the other raw materials and preparation process remain the same as in Example 1.

[0054] Test case Mechanical properties: Tensile strength and elongation at break were tested under the following conditions: ambient temperature 25℃, ambient humidity 40%. The test method involved opening the tensile testing software, selecting the tensile test for plastic film, setting the displacement control to 100 mm / min, initial displacement to 180 mm, and test width to 15 mm. Measurements were performed using a universal tensile testing machine. Bond strength: A T-peel test was conducted by laminating a PE protective film and adhesive to both sides of the TAC film and then performing a T-peel test using a universal tensile testing machine.

[0055] Performance tests were conducted on Examples 1-8 and Comparative Examples 1-3, and the results are shown in Table 1: Table 1

[0056] As shown in Table 1, the comparison between Example 1 and Comparative Examples 1–3 demonstrates that the TAC-based film itself possesses excellent bonding strength and mechanical properties. Treating the TAC-based film with low-temperature plasma can increase the number of polar groups on the film surface, thereby improving the bonding strength; however, since the introduction of polar groups originates from the breakage of polymer chain segments, the mechanical properties of the film will correspondingly decrease. In Examples 1–8, by combining low-temperature plasma surface activation with a synergistic effect of phenylboronic acid-terminated cellulose acetate stabilizer, the surface bonding performance of the TAC film was significantly improved while effectively solving the problem of decreased mechanical properties caused by plasma treatment.

[0057] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a TAC film with high bonding strength, characterized in that, Includes the following steps: Cellulose triacetate, stabilizer, plasticizer, UV stabilizer and solvent are mixed and dissolved under heating and stirring conditions to form a uniform TAC solution. The TAC base film is obtained by casting and drying. The TAC base film is subjected to low-temperature plasma treatment and then is kept at a constant temperature of 80-100℃ for 2-4 hours to obtain a TAC film with high bonding strength. The stabilizer is cellulose acetate capped with phenylboronic acid.

2. The method for preparing a high-adhesion-strength TAC film according to claim 1, characterized in that, The conditions for the low-temperature plasma treatment are: pressure 0.1-0.4 MPa, plasma treatment time 4-8 min.

3. The method for preparing a high-adhesion-strength TAC film according to claim 1, characterized in that, The low-temperature plasma used in the low-temperature plasma treatment is one of oxygen low-temperature plasma and nitrogen low-temperature plasma.

4. The method for preparing a high-adhesion-strength TAC film according to claim 1, characterized in that, The mass ratio of cellulose triacetate, plasticizer, and UV stabilizer is 90-95:5-10:1-3; the solid content of the TAC solution is 10%-20%; and the amount of stabilizer added is 4%-7% of the mass of cellulose triacetate.

5. The method for preparing a high-adhesion-strength TAC film according to claim 1, characterized in that, The plasticizer is at least one of sucrose benzoate and tributyl citrate; The UV absorber is a benzotriazole-based UV absorber.

6. The method for preparing a high-adhesion-strength TAC film according to claim 1, characterized in that, The stabilizer is prepared by the following steps: Cellulose diacetate and aminosilane coupling agent are added to a solvent, and the mixture is heated under reflux for 18-30 hours to obtain cellulose acetate modified with aminosilane coupling agent. Aminosilane coupling agent-modified cellulose acetate and formylphenylboronic acid were added to methanol and stirred at room temperature for 12-16 hours. The methanol was then removed by vacuum concentration to obtain the stabilizer.

7. The method for preparing a high-adhesion-strength TAC film according to claim 6, characterized in that, The mass ratio of cellulose diacetate to aminosilane coupling agent is 1:2-3; the mass ratio of cellulose diacetate to solvent is 1g:150-200mL; and the mass ratio of aminosilane coupling agent-modified cellulose acetate to formylphenylboronic acid is 2:0.8-0.

9.

8. The method for preparing a high-adhesion-strength TAC film according to claim 6, characterized in that, The formylphenylboronic acid is one of o-formylphenylboronic acid, m-formylphenylboronic acid, and p-formylphenylboronic acid.

9. The method for preparing a high-adhesion-strength TAC film according to claim 6, characterized in that, The aminosilane coupling agent is one of γ-aminopropyltriethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, and γ-aminopropylmethyldiethoxysilane.

10. A high-adhesion-strength TAC membrane, characterized in that, Prepared by the preparation method according to any one of claims 1-9.

Images