A TAC film with high bonding strength and preparation method thereof

Abstract

The present invention provides a TAC film with high bonding strength, which comprises 50-95 parts of cellulose, 1-20 parts of plasticizer, 0.5-5 parts of UV absorber, and 0.5-20 parts of a compound containing at least one ester group and a hydroxyl group by weight. The TAC film of the present invention has excellent mechanical properties such as tensile strength and elongation by using specific ingredients and saponifying the TAC film. The tensile strength of the improved TAC film is ≥95MPa, and the elongation is ≥10%; it has excellent bonding strength, the peak area of ​​the hydroxyl peak on the surface of the obtained TAC film is ≥50.00, and the bonding force between the TAC film and the TAC film is ≥10.00N / 25cm. In the process of preparing a laminate structure in subsequent applications, the problem of separation between the film layers during the heating and bending process can be effectively avoided. The TAC film and preparation method provided by the present invention are simple in conditions, suitable for industrial production, and have broad application prospects.

Description

Technical Field

[0001] The invention relates to the technical field of polymer protective films, and specifically provides a TAC film with high bonding strength and a preparation method thereof. Background Art

[0002] Due to its excellent optical and mechanical properties, triacetyl cellulose film (TAC film) is widely used in polarized lenses. Polarized lenses consist of a polarizer and multiple layers of TAC film on either side of the polarizer. In recent years, China has vigorously promoted the development of the tourism industry, and outdoor travel has become popular among young people, leading to the rapid development of personalized, high-end and fashionable polarized glasses. The main production process of polarized glasses is as follows: TAC raw film - slitting - saponification - lamination - heating and bending - finished lenses. The main structure of polarized glasses is composed of multiple layers of thin films bonded together to form a smooth laminate. The laminate is then heated, bent, and cut into polarized lenses.

[0003] The laminate structure of polarized eyeglass lenses primarily consists of multiple layers of TAC film, PVA polarizing film, and adhesive. The TAC film requires saponification during the bonding process, which often compromises the bond strength between the TAC film layers due to inefficient interfacial reaction between the TAC film and the saponifying solution. The resulting laminate often experiences separation between the film layers during the heat-bending process, leading to process failure and impacting product performance. However, due to the inherently brittle nature of the TAC film, which exhibits a low elongation at break, it is prone to breakage during production and processing.

[0004] Chinese patent CN206384634U discloses a TAC film pretreatment device, which includes an unwinding rack, an unwinding film storage box, an alkali solution cleaning tank, a pure water cleaning tank, an oven, a winding film storage box and a winding rack, which are arranged in sequence along the forward direction of the TAC film. The TAC film is processed through the process of unwinding → alkali washing → water washing → drying → winding to improve the bonding performance of TAC. The specific method is to first prepare a certain concentration of sodium hydroxide alkali solution and preheat it to the process temperature, and then immerse the TAC film in the alkali solution at a certain speed for cleaning. This step is mainly to saponify the surface of the TAC; then wash it in a pure water tank. This step is mainly to clean the alkali solution remaining on the surface of the TAC. This method can improve the bonding performance of the TAC film within a certain range, but because the saponification reaction of the TAC film is only on the surface of the TAC film, and the speed of the saponification reaction during the production process affects the speed of the entire production line, efficient and high-strength bonding performance cannot be guaranteed in this method. Summary of the Invention

[0005] In response to the above problems, the present invention provides a TAC film with high bonding strength and a preparation method thereof. By using specific ingredients and saponifying the TAC film, the film has excellent mechanical properties such as tensile strength and elongation and high bonding strength. In the subsequent application of preparing a laminate structure, the problem of separation between film layers during the heating and bending process can be effectively avoided.

[0006] In a first aspect, the present invention provides a TAC film with high bonding strength, comprising, by weight, 50-95 parts of cellulose, 1-20 parts of a plasticizer, 0.5-5 parts of a UV absorber, and 0.5-20 parts of a compound containing at least one ester group and a hydroxyl group.

[0007] Preferably, the TAC film comprises, by weight, 70-90 parts of cellulose, 5-10 parts of plasticizer, 1-5 parts of UV absorber, and 5-10 parts of a compound containing at least one ester group and a hydroxyl group.

[0008] Preferably, the acylation degree of the cellulose is 56%-64%.

[0009] Preferably, the plasticizer is a mixture of one or more of triphenyl phosphate, quaternary diphenyl phosphate, bisphenyloxy diphenyl phosphate, sucrose benzoate, and tributyl citrate.

[0010] More preferably, the plasticizer is one of triphenyl phosphate and quaternary diphenyl phosphate, or a mixture of the two.

[0011] Preferably, the UV absorber is 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2,4-di-tert-butyl-6-(5-chlorobenzotriazole-2-yl)phenol, 2-(2'-hydroxy-3',5'-di-tert-pentylphenyl)benzotriazole. The UV absorber in the present invention can be a plasticizer or a mixture of one or more thereof.

[0012] More preferably, the UV absorber is 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole and / or 2,4-di-tert-butyl-6-(5-chlorobenzotriazole-2-yl)phenol.

[0013] Preferably, in the compound containing at least one ester group and a hydroxyl group, the mass content of the ester group is 1-15%; the mass content of the hydroxyl group is 1-20%.

[0014] Further preferably, the compound containing at least one ester group and a hydroxyl group is a mixture of one or more of isobutyl p-hydroxybenzoate, n-butyl p-hydroxybenzoate, polycaprolactone polyol and polycarbonate diol.

[0015] More preferably, the compound containing at least one ester group and a hydroxyl group is a mixture of one or more of isobutyl hydroxybenzoate, n-butyl p-hydroxybenzoate and polycarbonate diol.

[0016] The inventors discovered that when the mass content of the ester group in the compound containing at least one ester group and hydroxyl group is 1-15% and the mass content of the hydroxyl group is 1-20%, the TAC film obtained has excellent mechanical properties and adhesion. The inventors analyzed that the TAC film is a material containing a large number of high molecular groups. By increasing the hydroxyl group content, the long carbon chain of the TAC film has more molecular branches, and the interfacial reaction efficiency of the TAC film in the subsequent saponification reaction is improved, thereby effectively enhancing the adhesion strength of the TAC film. The inventors unexpectedly discovered that when using specific compounds containing at least one ester group and hydroxyl group, it can also effectively enhance mechanical properties such as tensile strength and avoid the precipitation of plasticizers. The inventors analyzed that it may be due to the introduction of specific hydroxyl and ester groups, which not only enhances the adhesion strength, but also the compound containing at least one ester group and hydroxyl group forms intermolecular hydrogen bonds with other components in the system, further enhancing the mechanical properties and intermolecular forces of the TAC film material. However, if the content of hydroxyl and ester groups is too high, it is easy to cause cross-linking between macromolecules and agglomeration of macromolecules, which will affect the uniform dispersion of components in the system and affect the mechanical properties of the TAC film.

[0017] A second aspect of the present invention provides a method for preparing a TAC film with high bonding strength, the specific steps of which are as follows:

[0018] The raw materials are dissolved in a solvent and stirred to obtain a cotton gum solution, which is then transported into a casting nozzle and cast onto a support through extrusion to obtain the TAC film.

[0019] Further preferably, the method for preparing the TAC film with high bonding strength comprises the following specific steps:

[0020] Cellulose, plasticizer, UV absorber, and hydroxyl- and ester-containing compounds are dissolved in a mixed solvent of dichloromethane and methanol, and mechanically stirred at room temperature and pressure to form a transparent and uniform gel-like cotton glue solution, wherein the solid content of the cotton glue solution is controlled within the range of 10% to 25%. The cotton glue solution is conveyed to a casting nozzle through a conveying pump, and extruded and cast onto a continuously operating support body at a speed of 1 to 25 m / min to obtain the TAC film. The TAC film is peeled, dried, trimmed, embossed, and rolled to obtain a rolled TAC film, wherein the moisture content of the TAC film is controlled within 3%.

[0021] Preferably, the TAC film is further subjected to saponification treatment, and the specific steps of the saponification treatment are as follows:

[0022] S1: Place the TAC membrane in a saponification solution at 30-70°C for 0.5-10 minutes, then rinse the TAC membrane with water.

[0023] S2: Place the TAC film in an oven at 60-120° C. to dry, and take out a sample to obtain the saponified TAC film.

[0024] Preferably, the saponification solution comprises, by weight, 0.1-20% of alkali solution, 0.1-5% of low-molecule alcohol, 0.1-1% of interface treatment agent, and the balance water.

[0025] Further preferably, the saponification solution comprises, by weight, 10-20% of alkali solution, 2-5% of low-molecule alcohol, 0.5-1% of interface treatment agent, and the balance water.

[0026] Preferably, the alkali solution comprises an organic base and an inorganic base.

[0027] More preferably, the organic base is a mixture of one or more of sodium methoxide, sodium ethoxide, potassium ethoxide, and sodium tert-butoxide.

[0028] More preferably, the organic base is sodium methoxide, sodium ethoxide or a mixture of the two.

[0029] Preferably, the inorganic base is a mixture of one or more of sodium hydroxide, potassium hydroxide and calcium hydroxide.

[0030] More preferably, the inorganic base is potassium hydroxide, calcium hydroxide or a mixture of the two.

[0031] Further preferably, the mass ratio of the organic base to the inorganic base is (0.5-1.5):1.

[0032] Further preferably, the mass ratio of the organic base to the inorganic base is (0.8-1.1):1.

[0033] In the prior art, potassium hydroxide or potassium hydroxide is often used as an alkali solution to saponify the TAC film, but the reaction is often incomplete and only reacts on the surface of the TAC film. The resulting TAC film has poor adhesion, which causes the problem of separation between film layers during the use of TAC. The inventors found that when an organic base and an inorganic base are used together, especially when the mass ratio of the organic base to the inorganic base is (0.5-1.5): 1, the TAC film after saponification has excellent adhesion. The inventors analyzed that this may be due to the simultaneous use of an organic base and an inorganic base for treatment, which can effectively accelerate the reaction speed and make the saponification reaction more thorough. The inorganic base can effectively carry out the saponification reaction, and the organic base component used can effectively penetrate the TAC film because it contains an organic group at the same time, so that the alkali solution can be quickly and evenly dispersed, fully contacted with the membrane components, and the saponification reaction of the TAC film is more thorough, which is conducive to increasing the reaction rate and improving the utilization rate of raw materials, thereby effectively enhancing adhesion. Furthermore, using organic and inorganic bases in a specific ratio can prevent local overconcentration of the inorganic base, which can lead to uneven reaction of the TAC film and affect its adhesion and mechanical properties. However, if the organic base content is high, the content of the strong inorganic base is reduced, which can also lead to incomplete saponification reaction and affect adhesion.

[0034] Preferably, the small molecule alcohol is one or more of methanol, ethanol, isopropanol, n-butanol, phenylethyl alcohol, phenylpropyl alcohol, and cyclohexanol.

[0035] More preferably, the small molecule alcohols are methanol and ethanol.

[0036] The inventors found that when methanol and ethanol are used simultaneously, the reaction is more uniform. The combined use of the two can enhance the dissolution and dispersion of the components in the system, making the molecular contact between the alkali solution and the TAC film more complete and the saponification reaction more thorough.

[0037] Preferably, the interface treatment agent is one or more of sodium dodecyl sulfate, sodium dodecyl sulfonate, and sodium dodecylbenzene sulfonate.

[0038] More preferably, the interface treatment agent is sodium dodecylbenzenesulfonate.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The TAC film of the present invention, through the use of specific ingredients and saponification treatment of the TAC film, has excellent mechanical properties such as tensile strength and elongation. The improved TAC film has a tensile strength of ≥95MPa and an elongation of ≥10%. It also has excellent adhesion, with the peak area of ​​the hydroxyl peak on the surface of the prepared TAC film being ≥50.00, and the adhesion between TAC films being ≥10.00N / 25cm. In the subsequent application of the laminate structure, the problem of separation between film layers during the heating and bending process can be effectively avoided. The TAC film and preparation method provided by the present invention are simple to prepare, suitable for industrial production, and have broad application prospects. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be noted that the following embodiments are for further explanation of the present invention, rather than for limitation thereof.

[0042] Example

[0043] Example 1

[0044] On the one hand, this embodiment provides a TAC film with high bonding strength, comprising, by weight:

[0045] Cellulose: 88 parts, purchased from Sichuan Pushi Cellulose Acetate Co., Ltd.

[0046] UV absorber: 2 parts of 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole; purchased from Jiangxi Lotte Chemical Co., Ltd.

[0047] Compound containing at least one ester group and a hydroxyl group: 5 parts of n-butyl p-hydroxybenzoate, purchased from Hubei Qifei Pharmaceutical Chemical Co., Ltd.

[0048] Plasticizer: 5 parts of triphenyl phosphate, purchased from Heze Dijie Chemical Co., Ltd.

[0049] On the other hand, this embodiment provides a method for preparing a TAC film with high bonding strength, and the specific steps are as follows:

[0050] TAC, plasticizer, UV absorber, and hydroxyl- and ester-containing compounds were dissolved in a mixed solvent of dichloromethane and methanol. The solution was mechanically stirred at 100 rpm at room temperature and pressure for 10 hours to form a transparent, uniform, gel-like collodion solution with a solids content of 15%. The collodion solution was allowed to stand at room temperature for at least 10 hours to defoam. The collodion solution was pumped into a casting nozzle and extruded onto a continuously running steel belt at a speed of 15 m / min. The TAC film was initially dried on the steel belt and with hot air. The moisture content of the TAC film was controlled to 25% when peeled off from the front drum. The film was then dried in a drying oven at 80°C, trimmed, embossed, and wound to produce a roll-formed TAC film with a thickness of 150 μm. The moisture content of the finished TAC film at the winding stage was controlled to less than 3%.

[0051] The TAC film is further subjected to saponification treatment, and the specific steps of the saponification treatment are as follows:

[0052] A TAC film with apparent good quality is placed vertically in a saponification solution at 50°C, and the TAC film is reacted in the saponification solution for 8 minutes. After being taken out, the residual saponification solution and other substances on the film are rinsed clean with hot water (about 3 minutes). Then, the TAC sample is hung with clips and dried in a 100°C oven for 30 minutes to dry the residual moisture on the film. The sample is taken out, and the saponification treatment of the sample is completed to obtain the saponified TAC film.

[0053] The saponified liquid comprises, by weight percentage:

[0054] Organic base: 9%, sodium ethoxide;

[0055] Inorganic base: 10%, potassium hydroxide;

[0056] Small molecule alcohols: 2.5% methanol, 2.5% ethanol;

[0057] Interface treatment agent: 1% sodium dodecylbenzenesulfonate;

[0058] Water: 75%.

[0059] Example 2

[0060] On the one hand, this embodiment provides a TAC film with high bonding strength, comprising, by weight:

[0061] Cellulose: 84 parts, purchased from Sichuan Pushi Cellulose Acetate Co., Ltd.

[0062] UV absorber: 1 part of 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole; purchased from Jiangxi Lotte Chemical Co., Ltd.

[0063] Compounds containing at least one ester group and a hydroxyl group: 5 parts of isobutyl p-hydroxybenzoate and 5 parts of n-butyl p-hydroxybenzoate; purchased from Hubei Qifei Pharmaceutical Chemical Co., Ltd.

[0064] Plasticizer: 5 parts of triphenyl phosphate; purchased from Heze Dijie Chemical Co., Ltd.

[0065] On the other hand, this embodiment provides a method for preparing a TAC film with high bonding strength, and the specific steps are the same as those in Example 1.

[0066] The TAC film is further subjected to saponification treatment, and the specific steps of the saponification treatment are as follows:

[0067] A TAC film with apparent good quality is placed vertically in a saponification solution at 50°C, and the TAC film is reacted in the saponification solution for 8 minutes. After being taken out, the residual saponification solution and other substances on the film are rinsed clean with hot water (about 3 minutes). Then, the TAC sample is hung with clips and dried in a 100°C oven for 30 minutes to dry the residual moisture on the film. The sample is taken out, and the saponification treatment of the sample is completed to obtain the saponified TAC film.

[0068] The saponified liquid comprises, by weight percentage:

[0069] Organic base: 5%, sodium ethoxide;

[0070] Inorganic base: 5%, potassium hydroxide, 5% sodium hydroxide;

[0071] Small molecule alcohols: 2.5% methanol, 2% ethanol;

[0072] Interface treatment agent: 0.5% sodium dodecylbenzenesulfonate;

[0073] Purified water: 80%.

[0074] Example 3

[0075] On the one hand, this embodiment provides a TAC film with high bonding strength, comprising, by weight:

[0076] Cellulose: 82 parts, purchased from Sichuan Pushi Cellulose Acetate Co., Ltd.

[0077] UV absorber: 2.5 parts of 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2.5 parts of 2,4-di-tert-butyl-6-(5-chlorobenzotriazol-2-yl)phenol; purchased from Jiangxi Lotte Chemical Co., Ltd.

[0078] Compounds containing at least one ester group and a hydroxyl group: 2 parts of n-butyl p-hydroxybenzoate and 6 parts of isobutyl p-hydroxybenzoate; purchased from Hubei Qifei Pharmaceutical Chemical Co., Ltd.

[0079] Plasticizer: 5 parts of triphenyl phosphate; purchased from Heze Dijie Chemical Co., Ltd.

[0080] On the other hand, this embodiment provides a method for preparing a TAC film with high bonding strength, and the specific steps are the same as those in Example 1.

[0081] The TAC film is further subjected to saponification treatment, and the specific steps of the saponification treatment are as follows:

[0082] A TAC film with apparent good quality is placed vertically in a saponification solution at 50°C, and the TAC film is reacted in the saponification solution for 8 minutes. After being taken out, the residual saponification solution and other substances on the film are rinsed clean with hot water (about 3 minutes). Then, the TAC sample is hung with clips and dried in a 100°C oven for 30 minutes to dry the residual moisture on the film. The sample is taken out, and the saponification treatment of the sample is completed to obtain the saponified TAC film.

[0083] The saponified liquid comprises, by weight percentage:

[0084] Organic base: 5%, sodium methoxide, 2% sodium ethoxide;

[0085] Inorganic base: 6% potassium hydroxide, 1% calcium hydroxide;

[0086] Small molecule alcohols: 1% methanol, 1% ethanol;

[0087] Interface treatment agent: 1% sodium dodecylbenzenesulfonate

[0088] Purified water: 83%.

[0089] Example 4

[0090] On the one hand, this embodiment provides a TAC film with high bonding strength, comprising, by weight:

[0091] Cellulose: 78 parts, purchased from Sichuan Pushi Cellulose Acetate Co., Ltd.

[0092] UV absorber: 1 part 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 1 part 2,4-di-tert-butyl-6-(5-chlorobenzotriazol-2-yl)phenol; purchased from Jiangxi Lotte Chemical Co., Ltd.

[0093] Compound containing at least one ester group and hydroxyl group: 6 parts of n-butyl p-hydroxybenzoate and 4 parts of polycarbonate diol; purchased from Wuhan Chengtian Fine Chemical Co., Ltd.

[0094] Plasticizer: 5 parts of triphenyl phosphate and 5 parts of quaternary diphenyl phosphate; purchased from Heze Dijie Chemical Co., Ltd.

[0095] On the other hand, this embodiment provides a method for preparing a TAC film with high bonding strength, and the specific steps are the same as those in Example 1.

[0096] The TAC film is further subjected to saponification treatment, and the specific steps of the saponification treatment are as follows:

[0097] A TAC film with apparent good quality is placed vertically in a saponification solution at 50°C, and the TAC film is reacted in the saponification solution for 8 minutes. After being taken out, the residual saponification solution and other substances on the film are rinsed clean with hot water (about 3 minutes). Then, the TAC sample is hung with clips and dried in a 100°C oven for 30 minutes to dry the residual moisture on the film. The sample is taken out, and the saponification treatment of the sample is completed to obtain the saponified TAC film.

[0098] The saponified liquid comprises, by weight percentage:

[0099] Organic base: 9%, sodium ethoxide;

[0100] Inorganic base: 10%, potassium hydroxide;

[0101] Cleaving agent: 2.5% methanol, 2.5% ethanol;

[0102] Interface treatment agent: 1% sodium dodecylbenzenesulfonate;

[0103] Purified water: 75%.

[0104] Comparative Example 1

[0105] On the one hand, this embodiment provides a TAC film with high bonding strength, comprising, by weight:

[0106] Cellulose: 93 parts, purchased from Sichuan Pushi Cellulose Acetate Co., Ltd.

[0107] UV absorber: 2 parts of 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, purchased from Jiangxi Lotte Chemical Co., Ltd.

[0108] Plasticizer: 5 parts of triphenyl phosphate; purchased from Heze Dijie Chemical Co., Ltd.

[0109] On the other hand, this embodiment provides a method for preparing a TAC film with high bonding strength, and the specific steps are the same as those in Example 1.

[0110] The TAC film is further subjected to saponification treatment, and the specific steps of the saponification treatment are the same as those in Example 1.

[0111] The saponified liquid comprises, by weight percentage:

[0112] Inorganic base: 10%, potassium hydroxide;

[0113] Small molecule alcohols: 2.5% methanol, 2.5% ethanol;

[0114] Interface treatment agent: 1% sodium dodecylbenzenesulfonate;

[0115] Water: 84%.

[0116] Comparative Example 2

[0117] On one hand, this embodiment provides a TAC film with high bonding strength. The specific raw materials are the same as those in Example 4, calculated by weight.

[0118] On the other hand, this embodiment provides a method for preparing a TAC film with high bonding strength, and the specific steps are the same as those in Example 4.

[0119] The TAC film is further subjected to saponification treatment, and the specific steps of the saponification treatment are the same as those in Example 4.

[0120] The saponified liquid comprises, by weight percentage:

[0121] Inorganic base: 5%, potassium hydroxide, 5% sodium hydroxide;

[0122] Small molecule alcohols: 2.5% methanol, 2.5% ethanol;

[0123] Interface treatment agent: 1% sodium dodecylbenzenesulfonate;

[0124] Water: 84%.

[0125] Comparative Example 3

[0126] On the one hand, this embodiment provides a TAC film with high bonding strength, comprising, by weight:

[0127] Cellulose: 88 parts, purchased from Sichuan Pushi Cellulose Acetate Co., Ltd.

[0128] UV absorber: 2 parts of 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole; purchased from Jiangxi Lotte Chemical Co., Ltd.

[0129] Compound containing at least one ester group and a hydroxyl group: 5 parts of n-butyl p-hydroxybenzoate; purchased from Hubei Qifei Pharmaceutical Chemical Co., Ltd.

[0130] Plasticizer: 5 parts of triphenyl phosphate; purchased from Heze Dijie Chemical Co., Ltd.

[0131] On the other hand, this embodiment provides a method for preparing a TAC film with high bonding strength, and the specific steps are the same as those in Example 1.

[0132] The TAC film is further subjected to saponification treatment, and the specific steps of the saponification treatment are the same as those in Example 1.

[0133] The saponified liquid comprises, by weight percentage:

[0134] Inorganic base: 10%, potassium hydroxide;

[0135] Small molecule alcohols: 2.5% methanol, 2.5% ethanol;

[0136] Interface treatment agent: 1% sodium dodecylbenzenesulfonate;

[0137] Water: 84%.

[0138] Comparative Example 4

[0139] On the one hand, this embodiment provides a TAC film with high bonding strength, comprising, by weight:

[0140] Cellulose: 94 parts, purchased from Sichuan Pushi Cellulose Acetate Co., Ltd.

[0141] UV absorber: 1 part of 2'-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole; purchased from Jiangxi Lotte Chemical Co., Ltd.

[0142] Plasticizer: 5 parts of triphenyl phosphate; purchased from Heze Dijie Chemical Co., Ltd.

[0143] On the other hand, this embodiment provides a method for preparing a TAC film with high bonding strength, and the specific steps are the same as those in Example 1.

[0144] The TAC film is further subjected to saponification treatment, and the specific steps of the saponification treatment are the same as those in Example 1.

[0145] The saponified liquid comprises, by weight percentage:

[0146] Organic base: 5%, sodium methoxide, 5% sodium ethoxide;

[0147] Inorganic base: 4% potassium hydroxide, 1% calcium hydroxide;

[0148] Small molecule alcohols: 2% methanol, 1% ethanol;

[0149] Water: 82%

[0150] Performance Testing

[0151] 1. Tensile strength-elongation at break test:

[0152] 1) Sample preparation: The saponified TAC films were extruded and bonded to each other, and then heated at 60-120°C.

[0153] Dry in an oven for 30 minutes, take out and complete the TAC film lamination and sample preparation.

[0154] 2) Test environment: ambient temperature 25°C, ambient humidity 40%.

[0155] 3) Test method: Open the tensile test software, select the plastic film tensile test in the software, and set the parameters as follows:

[0156] Displacement control: 100mm / min; initial displacement: 180mm; test width: 15mm.

[0157] A universal tensile testing machine was used to carry out mechanical properties tensile strength-elongation at break tests.

[0158] 2. Adhesion Strength Test: Using a T-type peel test, PE protective film and adhesive are laminated on both sides of the TAC film laminate. Both film layers are laminated with adhesive. T-type peel test is performed using a universal tensile testing machine.

[0159] 1) Test environment: ambient temperature 25°C, ambient humidity 40%;

[0160] 2) Test method: Open the tensile testing software and select the adhesive T peel strength test (flexible material to flexible material) in the software. Set the parameters as follows:

[0161] Displacement control: 50mm / min; Entry force: 0.05N; Number of removal points: 5; Constant force attenuation amplitude: 80%; Test width: 25mm;

[0162] 3. Hydroxyl content test:

[0163] 1) Test environment: ambient temperature 25°C, ambient humidity 40%

[0164] 2) Test method: Open the infrared test software and set the parameters as follows:

[0165] Scan number: 32, resolution 4.000, wave number: 1000-4000cm -1

[0166] 3) After scanning, at 3400-3600cm -1 The strong absorption peak is the -OH peak, and the corrected area of ​​the peak position can be obtained through the software.

[0167] The tensile strength, elongation at break, hydroxyl content and adhesive strength of the TAC films of Examples 1-4 and Comparative Examples 1-4 were tested. The test results are shown in Table 1 below.

[0168] Table 1

[0169]

Claims

1. A method for preparing a TAC film with high bonding strength, characterized in that: The specific steps are as follows: The raw materials are dissolved in a solvent and stirred to obtain a cotton gum solution, which is then transported to a casting nozzle and cast onto a support through extrusion to obtain the TAC film. The TAC film is further subjected to a saponification treatment, and the specific steps of the saponification treatment are as follows: S1: Place the TAC membrane in a saponification solution at 30-70°C for 0.5-10 minutes, then rinse the TAC membrane with water. S2: drying the TAC film in an oven at 60-120° C. and taking out a sample to obtain the saponified TAC film; The raw materials include, by weight, 70-90 parts of cellulose, 5-10 parts of a plasticizer, 1-5 parts of a UV absorber, and 5-10 parts of a compound containing at least one ester group and a hydroxyl group; the compound containing at least one ester group and a hydroxyl group is a mixture of one or more of isobutyl hydroxybenzoate, n-butyl p-hydroxybenzoate, and polycarbonate diol; The saponification solution comprises, by weight, 0.1-20% alkali solution, 0.1-5% small molecule alcohol, 0.1-1% interface treatment agent, and the balance water; the alkali solution comprises an organic base and an inorganic base; the mass ratio of the organic base to the inorganic base is (0.5-1.5):1; the small molecule alcohol is methanol and ethanol.

2. The method for preparing a TAC film with high bonding strength according to claim 1, wherein: The plasticizer is a mixture of one or more of triphenyl phosphate and quaternary diphenyl phosphate.

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