A cellulose acetate membrane and a method for preparing the same

Abstract

This invention relates to the field of cellulose acetate (TAC) membrane technology, specifically to a cellulose acetate membrane and its preparation method. The components include a solvent and solid components, by weight, wherein the solid components include: 80-110 parts cellulose, 5-10 parts plasticizer, and 0.1-5 parts benzotriazole derivative, with the solid components comprising 10-30 wt% of the total components. The prepared TAC membrane exhibits the following characteristics: fewer than 3 precipitates on the membrane surface; after high-temperature and high-humidity aging for 1000 h, the TAC membrane has a ΔE value < 0.10, a Δtsb transmittance (380nm-550nm value) < 0.5, and the area ratio of point-like, oily, and contaminant precipitates on the membrane surface is < 1%.

Description

Technical Field

[0001] This invention relates to the field of cellulose acetate (TAC) membrane technology, specifically to a cellulose acetate membrane and its preparation method. Background Technology

[0002] Cellulose acetate (TAC) film is a polymer material produced from cellulose and acetic acid through a series of chemical reactions. It is typically processed into thin films using solvent casting, exhibiting excellent transparency, optical properties, and physical and mechanical properties. Its preparation process primarily involves solution casting, but current processes have significant defects: during drying, polar solvents are extracted, and other small-molecule additives are carried away from the TAC film surface with solvent evaporation, accumulating on surfaces at low temperatures; the accumulation of these precipitates leads to quality issues. Furthermore, with the rapid development of the optoelectronic display field, TAC films must withstand high temperature and high humidity environments. Currently, common TAC films frequently experience additive precipitation under high temperature and humidity conditions, and their performance tends to decline, affecting product lifespan. With the continuous emergence of new materials and technological innovation, the performance of TAC films will continue to improve to meet the durability requirements of TAC films in increasingly demanding working environments.

[0003] Chinese invention patent CN103901521B discloses a polarizer protective film containing a resin, an ultraviolet absorber A having a maximum absorption value in the wavelength range of 350 to 400 nm, and an ultraviolet absorber B having a maximum absorption value in the wavelength range of 270 to 330 nm. Although this method can reduce the water vapor transmittance, its effect on the anti-exudation effect of TAC film is still not good. Chinese invention patent CN1789309B provides a so-called exudant plasticizer that has a viscosity-reducing effect and does not exudate or volatilize to the outside of the film. A cellulose ester film with high flatness and inhibiting plasticizer exudation is provided by a melt film-forming method that does not use halogen-based solvents with a large impact on the environment. The cellulose ester film is characterized by containing 1-25% by mass of a plasticizer composed of an ester compound formed by the condensation of an organic acid having the following general formula (1) with an alcohol of 3 or more ions. However, while the esterified organic acid and ternary or higher alcohols shown in the patent formula solved some of the precipitation on the TAC membrane when used as plasticizers, it was less effective for the precipitation on the TAC membrane guide shaft and had poor process adaptability. Summary of the Invention

[0004] The first aspect of the present invention provides a cellulose acetate membrane, comprising: a solvent and a solid component, wherein the solid component comprises: 80-110 parts of cellulose, 5-10 parts of plasticizer and 0.1-5 parts of benzotriazole derivative, and the content of the solid component in the composition is 10-30 wt%.

[0005] The plasticizer includes at least one of triphenyl phosphate, tributyl citrate, tributyl citrate, triethyl citrate, and sucrose benzoate.

[0006] The solvent includes at least one of dichloromethane and methanol.

[0007] Preferably, the solvent comprises a mixture of dichloromethane and methanol in a weight ratio of (58-90):(10-20).

[0008] The cellulose has an acetyl substitution degree of 50-70% and a degree of polymerization of 200-350.

[0009] Preferably, the cellulose has a degree of acetyl substitution of 55-65% and a degree of polymerization of 250-300.

[0010] The benzotriazole derivatives include monohydroxybenzotriazole derivatives and polyhydroxybenzotriazole derivatives.

[0011] Preferably, the solid components include: 80-110 parts of cellulose, 5-10 parts of plasticizer, 0.1-2 parts of monohydroxybenzotriazole derivative and 0.1-3 parts of polyhydroxybenzotriazole derivative.

[0012] More preferably, the solid components include: 80-100 parts of cellulose, 5-10 parts of plasticizer, 0.5-2 parts of monohydroxybenzotriazole derivative and 0.5-3 parts of polyhydroxybenzotriazole derivative.

[0013] The general structural formula of the monohydroxybenzotriazole derivative is shown in Formula 1: Wherein, R1 includes -S- or -O- groups, R2 includes one of an alkyl group with 1-20 carbon atoms, an aryl group with 6-18 carbon atoms, a cycloalkyl group with 1-10 carbon atoms, or an acyl group with 1-10 carbon atoms; R3 and R4 include one of an alkyl group with 1-20 carbon atoms, an aryl group with 6-20 carbon atoms, or a cycloalkyl group with 1-10 carbon atoms.

[0014] Preferably, R1 comprises -S- or -O-, R2 comprises one of an alkyl group with 1-10 carbon atoms, an aryl group with 6-12 carbon atoms, a cycloalkyl group with 1-8 carbon atoms, or an acyl group with 1-8 carbon atoms; and R3 and R4 comprise one of an alkyl group with 1-10 carbon atoms, an aryl group with 6-12 carbon atoms, or a cycloalkyl group with 1-8 carbon atoms.

[0015] The general structural formula of the polyhydroxybenzotriazole derivative is shown in Formula 2: R5 includes one of an alkyl group with 1-10 carbon atoms, an aryl group with 6-18 carbon atoms, a cycloalkyl group with 1-10 carbon atoms, or an acyl group with 1-10 carbon atoms; R6 includes one of an alkyl group with 1-20 carbon atoms, an aryl group with 6-20 carbon atoms, or a cycloalkyl group with 1-10 carbon atoms; R7 includes methyl or ethyl; and R8 includes -S-yl or -O-yl.

[0016] Preferably, R5 comprises one of an alkyl group with 1-8 carbon atoms, an aryl group with 6-10 carbon atoms, a cycloalkyl group with 1-8 carbon atoms, and an acyl group with 1-8 carbon atoms; R6 comprises one of an alkyl group with 1-10 carbon atoms, an aryl group with 6-12 carbon atoms, and a cycloalkyl group with 1-8 carbon atoms; R7 comprises methyl or ethyl; and R8 comprises -S-yl or -O-yl.

[0017] The weight ratio of the monohydroxybenzotriazole derivative to the polyhydroxybenzotriazole derivative is 1:(1-6).

[0018] Preferably, the weight ratio of the monohydroxybenzotriazole derivative to the polyhydroxybenzotriazole derivative is 1:(1-3).

[0019] Currently, common TAC membranes often experience additive precipitation under high temperature and high humidity conditions. The applicant's research found that adding benzotriazole derivatives, especially the simultaneous addition of monohydroxybenzotriazole derivatives and polyhydroxybenzotriazole derivatives, can effectively solve the problem of additive precipitation in TAC membranes under high temperature and high humidity conditions. This may be because the hydroxyl groups in the benzotriazole derivatives interact with the long cellulose chains, reducing the free volume and anchoring the additives in the system. Further research found that by limiting the weight ratio of monohydroxybenzotriazole derivatives to polyhydroxybenzotriazole derivatives to 1:(1-6), the precipitation resistance under high temperature and high humidity conditions can be further improved. After aging at high temperature and high humidity for 1000 hours, the ΔE value of the TAC membrane is <0.10, and there are no spot-like, oily, or dirt-like precipitates on the membrane surface.

[0020] A second aspect of the present invention provides a method for preparing a cellulose acetate membrane, comprising the following steps:

[0021] S1, cellulose, plasticizer, and benzotriazole derivative are added to a solvent to prepare a cotton glue solution;

[0022] S2, Spread the cotton glue solution onto the metal strip to form a liquid film, and then dry the liquid film;

[0023] S3, after drying, the liquid film is trimmed, balanced, embossed, and rolled up to obtain a cellulose acetate film.

[0024] The moisture content of the cellulose acetate membrane is less than 2 wt%.

[0025] Step S2 includes: spreading the cotton glue solution onto the metal strip to form a liquid film, peeling the liquid film off from the metal when the moisture content is 20-35wt%, and then entering the transition section and the post-drying section.

[0026] Preferably, step S2 includes: spreading the cotton glue solution onto the metal strip to form a liquid film, peeling the liquid film off from the metal when the moisture content is 20-30 wt%, and then proceeding to the transition section and the post-drying section.

[0027] The temperature of the subsequent drying shall not exceed 150°C.

[0028] Preferably, the post-drying temperature is not higher than 130°C.

[0029] Beneficial effects

[0030] 1. Adding benzotriazole derivatives, especially simultaneously adding monohydroxybenzotriazole derivatives and polyhydroxybenzotriazole derivatives, can effectively solve the problem of additive precipitation in TAC membranes under high temperature and high humidity conditions.

[0031] 2. By limiting the weight ratio of monohydroxybenzotriazole derivatives to polyhydroxybenzotriazole derivatives to 1:

[0032] (1-6) can further improve the precipitation resistance under high temperature and high humidity, with less than 0.5wt% of oily substances precipitated after high temperature and high humidity, and less than 3 precipitation strips on the membrane surface.

[0033] 3. By limiting the weight ratio of monohydroxybenzotriazole derivatives to polyhydroxybenzotriazole derivatives to 1:

[0034] (1-3) can improve the high temperature and high humidity aging performance of the membrane. After 1000h of high temperature and high humidity aging, the ΔE value of the TAC membrane is <0.10, Δtsb <0.5, and there are no dot-like, oily, or dirt-like precipitates on the membrane surface.

[0035] 4. The solvent includes a mixture of dichloromethane and methanol in a weight ratio of (58-90):(10-20), which can further improve the resistance to precipitation under high temperature and high humidity, and the precipitation of oily substances after high temperature and high humidity is ≤0.3wt%.

[0036] 5. The preparation method of this application is simple and can be applied on a large scale. Detailed Implementation

[0037] Example 1

[0038] A cellulose acetate membrane comprises a solvent and a solid component, wherein the solid component includes 92 parts of cellulose, 6 parts of plasticizer, and 2 parts of benzotriazole derivative, and the content of the solid component in the composition is 20 wt%.

[0039] The solvent is a mixture of dichloromethane and methanol in a weight ratio of 85:15.

[0040] The cellulose has an acetyl substitution degree of 61.0% and a degree of polymerization of 280. It was purchased from Sichuan Push Cellulose Acetate Co., Ltd., and its model number is H12123.

[0041] The plasticizer is 3 parts triphenyl phosphate and 3 parts tributyl citrate.

[0042] The benzotriazole derivative is a monohydroxybenzotriazole derivative and a polyhydroxybenzotriazole derivative, wherein the weight ratio of the monohydroxybenzotriazole derivative to the polyhydroxybenzotriazole derivative is 1:1.

[0043] The structure of the monohydroxybenzotriazole derivative is shown in Formula 1: In this context, R1 represents -S- group, R2 represents acetyl group, and R3 and R4 both represent methyl group.

[0044] The general structural formula of the polyhydroxybenzotriazole derivative is shown in Formula 2: Wherein, R5 represents ethyl, R6 represents butyl, R7 represents methyl, and R8 represents -S-yl.

[0045] A method for preparing a cellulose acetate membrane comprises the following steps:

[0046] S1. Add solvent to reaction vessel, and add plasticizer, precipitation modifier, durability aid and cellulose under stirring at 50 rpm to prepare cotton glue solution;

[0047] S2. After the cotton glue solution is extruded, it is evenly spread onto the stainless steel belt to form a liquid film. The liquid film is placed in a drying oven for preliminary drying. When its moisture content is 20wt%, it is peeled off from the steel belt and then enters the transition section and the post-drying (120℃) section.

[0048] S3. Trim, balance, emboss, and roll up the dried liquid film to obtain a cellulose acetate film with a moisture content of less than 2wt%.

[0049] Example 2

[0050] The specific implementation method is the same as in Example 1; the difference is that in Example 2, the solid components are: 88 parts of cellulose, 8 parts of plasticizer and 2 parts of benzotriazole derivative, and the content of the solid components in the composition is 20 wt%.

[0051] The solvent is a mixture of dichloromethane and methanol in a weight ratio of 85:15.

[0052] The cellulose has an acetyl substitution degree of 60.1% and a degree of polymerization of 275. It was purchased from Sichuan Push Cellulose Acetate Co., Ltd., and its model number is H12125.

[0053] The plasticizer is 3 parts triphenyl phosphate and 5 parts tributyl citrate.

[0054] The benzotriazole derivatives are monohydroxybenzotriazole derivatives and polyhydroxybenzotriazole derivatives, and the weight ratio of the monohydroxybenzotriazole derivatives to the polyhydroxybenzotriazole derivatives is 1:3.

[0055] The structure of the monohydroxybenzotriazole derivative is shown in Formula 1: R1 represents -S-yl, R2 represents phenyl; R3 represents butyl, and R4 all represent methyl.

[0056] The general structural formula of the polyhydroxybenzotriazole derivative is shown in Formula 2: R5 represents ethyl, R6 represents butyl; R7 represents methyl, and R8 represents -O-yl.

[0057] A method for preparing a cellulose acetate membrane, wherein in step S1, a solvent is added to a reaction vessel, and a plasticizer, a precipitation modifier, a durability aid, and cellulose are added under stirring at 70 rpm to obtain a cotton glue solution.

[0058] Example 3

[0059] The specific implementation method is the same as in Example 1; the difference is that in Example 3, the solid components are: 88 parts of cellulose, 10 parts of plasticizer and 2 parts of benzotriazole derivative, and the content of the solid components in the composition is 20 wt%.

[0060] The solvent is a mixture of dichloromethane and methanol in a weight ratio of 87:13.

[0061] The cellulose has an acetyl substitution degree of 60.1% and a degree of polymerization of 275. It was purchased from Sichuan Push Cellulose Acetate Co., Ltd., and its model number is H12125.

[0062] The plasticizer consists of 3 parts triphenyl phosphate, 3 parts tributyl citrate, and 4 parts triethyl citrate.

[0063] The benzotriazole derivative is a monohydroxybenzotriazole derivative and a polyhydroxybenzotriazole derivative, wherein the weight ratio of the monohydroxybenzotriazole derivative to the polyhydroxybenzotriazole derivative is 2:3.

[0064] The structure of the monohydroxybenzotriazole derivative is shown in Formula 1: R1 represents -S-yl, R2 represents hexyl; R3 represents propyl, and R4 both represent octyl.

[0065] The general structural formula of the polyhydroxybenzotriazole derivative is shown in Formula 2: R5 represents propyl, R6 represents butyl; R7 represents methyl, and R8 represents -S-yl.

[0066] A method for preparing a cellulose acetate membrane, wherein in step S1, a solvent is added to a reaction vessel, and a plasticizer, a precipitation modifier, a durability aid, and cellulose are added under stirring at 80 rpm to obtain a cotton glue solution.

[0067] Example 4

[0068] The specific implementation method is the same as in Example 1; the difference is that in Example 4, the solid components are: 91 parts of cellulose, 6 parts of plasticizer and 3 parts of benzotriazole derivative, and the content of the solid components in the composition is 20 wt%.

[0069] The solvent is a mixture of dichloromethane and methanol in a weight ratio of 85:15.

[0070] The cellulose has an acetyl substitution degree of 60.1% and a degree of polymerization of 275. It was purchased from Sichuan Push Cellulose Acetate Co., Ltd., and its model number is H12128.

[0071] The plasticizer is 3 parts sucrose benzoate and 3 parts tributyl citrate.

[0072] The benzotriazole derivative is a monohydroxybenzotriazole derivative and a polyhydroxybenzotriazole derivative, wherein the weight ratio of the monohydroxybenzotriazole derivative to the polyhydroxybenzotriazole derivative is 1:1.

[0073] The structure of the monohydroxybenzotriazole derivative is shown in Formula 1: R1 represents -S-yl, R2 represents butyl; R3 represents propyl, and R4 both represent octyl.

[0074] The general structural formula of the polyhydroxybenzotriazole derivative is shown in Formula 2: R5 represents biphenyl, R6 represents butyl; R7 represents methyl, and R8 represents -O-yl.

[0075] A method for preparing a cellulose acetate membrane, wherein in step S1, a solvent is added to a reaction vessel, and a plasticizer, a precipitation modifier, a durability aid, and cellulose are added under stirring at 70 rpm to obtain a cotton glue solution.

[0076] Comparative Example 1

[0077] A cellulose acetate membrane comprises a solvent and a solid component, wherein the solid component comprises 91 parts cellulose, 8 parts plasticizer, and 1 part ultraviolet absorber, and the content of the solid component in the composition is 20 wt%.

[0078] The ultraviolet absorber is 2-hydroxy-4-n-octyloxybenzophenone.

[0079] The solvent is a mixture of dichloromethane and methanol in a weight ratio of 85:15.

[0080] The cellulose has an acetyl substitution degree of 60.1% and a degree of polymerization of 275. It was purchased from Sichuan Push Cellulose Acetate Co., Ltd., and its model number is H12128.

[0081] The plasticizer is 5 parts by weight of sucrose benzoate and 3 parts by weight of tributyl citrate.

[0082] A method for preparing a cellulose acetate membrane comprises the following steps:

[0083] S1. Add solvent to reaction vessel, and add cellulose, plasticizer and ultraviolet absorber under stirring at 75 rpm to prepare cotton glue solution;

[0084] S2. After the cotton glue solution is extruded, it is evenly spread onto the stainless steel belt to form a liquid film. The liquid film is placed in a drying oven for preliminary drying. When its moisture content is 23wt%, it is peeled off from the steel belt and then enters the transition section and the post-drying section.

[0085] S3. Trimming, balancing, embossing, and winding yield the TAC film, ensuring that the moisture content of the final TAC film is reduced to below 2wt%.

[0086] Comparative Example 2

[0087] A cellulose acetate membrane comprises a solvent and a solid component, wherein the solid component comprises 90 parts cellulose, 8 parts plasticizer, and 2 parts ultraviolet absorber, and the content of the solid component in the composition is 20 wt%.

[0088] The ultraviolet absorber is 1 part by weight of 2-hydroxy-4-n-octyloxybenzophenone and 1 part by weight of 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole.

[0089] The solvent is a mixture of dichloromethane and methanol in a weight ratio of 90:10.

[0090] The cellulose has an acetyl substitution degree of 60.1% and a degree of polymerization of 275. It was purchased from Sichuan Push Cellulose Acetate Co., Ltd., and its model number is H12128.

[0091] The plasticizer is 5 parts by weight of sucrose benzoate and 3 parts by weight of tributyl citrate.

[0092] A method for preparing a cellulose acetate membrane, same as Comparative Example 1.

[0093] Comparative Example 3

[0094] A cellulose acetate membrane comprises a solvent and a solid component, wherein the solid component comprises 88 parts cellulose, 8 parts plasticizer, and 2 parts ultraviolet absorber, and the content of the solid component in the composition is 20 wt%.

[0095] The ultraviolet absorber is 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole.

[0096] The solvent is a mixture of dichloromethane and methanol in a weight ratio of 90:10.

[0097] The cellulose has an acetyl substitution degree of 60.1% and a degree of polymerization of 275. It was purchased from Sichuan Push Cellulose Acetate Co., Ltd., and its model number is H12128.

[0098] The plasticizer is 3 parts by weight of sucrose benzoate and 5 parts by weight of tributyl citrate.

[0099] A method for preparing a cellulose acetate membrane comprises the following steps:

[0100] S1. Add solvent to reaction vessel, and add cellulose, plasticizer and ultraviolet absorber under stirring at 75 rpm to prepare cotton glue solution;

[0101] S2. After the cotton glue solution is extruded, it is evenly spread onto the stainless steel belt to form a liquid film. The liquid film is placed in a drying oven for preliminary drying. When its moisture content is 26wt%, it is peeled off from the steel belt and then enters the transition section and the post-drying section.

[0102] S3. Trimming, balancing, embossing, and winding yield the TAC film, ensuring that the moisture content of the final TAC film is reduced to below 2wt%.

[0103] Comparative Example 4

[0104] A cellulose acetate membrane comprises a solvent and a solid component, wherein the solid component comprises 95 parts cellulose, 9 parts plasticizer, and 1 part ultraviolet absorber, and the content of the solid component in the composition is 20 wt%.

[0105] The ultraviolet absorber is 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole.

[0106] The solvent is a mixture of dichloromethane and methanol in a weight ratio of 95:5.

[0107] The cellulose has an acetyl substitution degree of 60.1% and a degree of polymerization of 275. It was purchased from Sichuan Push Cellulose Acetate Co., Ltd., and its model number is H12128.

[0108] The plasticizer is 9 parts by weight of sucrose benzoate.

[0109] A method for preparing a cellulose acetate membrane, same as Comparative Example 3.

[0110] Performance testing methods

[0111] The cellulose acetate (TAC) membranes prepared in the examples and comparative examples were subjected to the following performance tests, and the test data are listed in Table 1.

[0112] 1. Deposition lines on the surface of the TAC membrane:

[0113] The observation was conducted via online inspection, with the number of meters of film wound up to 1000m. The ambient temperature was 25-30℃ and the humidity was 40%-60%.

[0114] 2. Oily precipitation:

[0115] To induce oil precipitation in the sample, the completed TAC membrane was vertically placed in a sealed constant temperature and humidity chamber and aged for 1000 hours under specific ambient temperature and humidity conditions of 85°C and 85%. After aging, the TAC membrane was removed, and a layer of oil-absorbing paper was laid flat on both sides of the membrane. After standing at room temperature for 2 hours, the sum of the areas of oil-like precipitated substances on both sides of the TAC membrane was observed and counted using the grid point method.

[0116] 3. The L, a*, and b* values ​​of the TAC membrane were tested using a UV spectrophotometer. After the test, the TAC membrane was placed in a constant temperature and humidity chamber for durability testing. The test conditions were 85℃, 85%RH, and the test time was 1000h. After the test, the TAC membrane was removed and dried at room temperature. The L, a*, and b* values ​​of the TAC membrane were then retested.

[0117] ΔE=((ΔL) 2 +(Δa*) 2 +(Δb*) 2 ) 1 / 2

[0118] 4. The Tsb (380nm~500nm) of the TAC membrane was tested using an MT-330. After the test, the TAC membrane was placed in a constant temperature and humidity chamber for durability testing. The test conditions were 85℃, 85%RH, and the test time was 1000h. After the test, the TAC membrane was removed and dried at room temperature. The Tsb value of the TAC membrane was then measured again, and the difference between the two measurements was calculated.

[0119] Performance test data

[0120] Table 1

[0121]

Claims

1. A cellulose acetate membrane, characterized in that, The components include: solvent and solid components, in parts by weight, wherein the solid components include: 80-110 parts of cellulose, 5-10 parts of plasticizer and 0.1-5 parts of benzotriazole derivative, and the content of the solid components in the components is 10-30 wt%.

2. The cellulose acetate membrane according to claim 1, characterized in that, The benzotriazole derivatives include monohydroxybenzotriazole derivatives and polyhydroxybenzotriazole derivatives.

3. The cellulose acetate membrane according to claim 2, characterized in that, The solid components, by weight, include: 80-110 parts cellulose, 5-10 parts plasticizer, 0.1-2 parts monohydroxybenzotriazole derivative and 0.1-3 parts polyhydroxybenzotriazole derivative.

4. The cellulose acetate membrane according to claim 3, characterized in that, The general structural formula of the monohydroxybenzotriazole derivative is shown in Formula 1: Wherein, R1 includes -S- or -O- groups, R2 includes one of an alkyl group with 1-20 carbon atoms, an aryl group with 6-18 carbon atoms, a cycloalkyl group with 1-10 carbon atoms, or an acyl group with 1-10 carbon atoms; R3 and R4 include one of an alkyl group with 1-20 carbon atoms, an aryl group with 6-20 carbon atoms, or a cycloalkyl group with 1-10 carbon atoms.

5. The cellulose acetate membrane according to claim 3, characterized in that, The general structural formula of the polyhydroxybenzotriazole derivative is shown in Formula 2: R5 includes one of the following: an alkyl group with 1-10 carbon atoms, an aryl group with 6-18 carbon atoms, a cycloalkyl group with 1-10 carbon atoms, or an acyl group with 1-10 carbon atoms; R6 includes one of the following: an alkyl group with 1-20 carbon atoms, an aryl group with 6-20 carbon atoms, or a cycloalkyl group with 1-10 carbon atoms; R7 includes methyl or ethyl; and R8 includes -S-yl or -O-yl.

6. The cellulose acetate membrane according to claim 5, characterized in that, The weight ratio of the monohydroxybenzotriazole derivative to the polyhydroxybenzotriazole derivative is 1:(1-6).

7. A method for preparing a cellulose acetate membrane according to any one of claims 1-6, characterized in that, Includes the following steps: S1, cellulose, plasticizer, and benzotriazole derivative are added to a solvent to prepare a cotton glue solution; S2, Spread the cotton glue solution onto the metal strip to form a liquid film, and then dry the liquid film; S3, after drying, the liquid film is trimmed, balanced, embossed, and rolled up to obtain a cellulose acetate film.

8. The method for preparing the cellulose acetate membrane according to claim 7, characterized in that, The moisture content of the cellulose acetate membrane is less than 2 wt%.

9. The method for preparing the cellulose acetate membrane according to claim 8, characterized in that, Step S2 includes: spreading the cotton glue solution onto the metal strip to form a liquid film, peeling the liquid film off from the metal when the moisture content is 20-35wt%, and then entering the transition section and the post-drying section.

10. The method for preparing the cellulose acetate membrane according to claim 9, characterized in that, The temperature of the subsequent drying shall not exceed 150°C.

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