A fluorene-containing anti-glare coating material, a preparation method thereof, an anti-glare film, and a polarizing sheet

Abstract

The application provides a fluorene-containing anti-glare coating and a preparation method thereof, an anti-glare film, and a polarizer. In the preparation process of the fluorene-containing anti-glare coating, micron and nanometer silica with two different particle sizes are selected as dispersion particles, and the silica is subjected to fluorene grafting modification treatment, and then is introduced into the reaction in batches in the pre-polymerization and chain extension processes. The dispersion of the particles in the coating substrate is enhanced, the agglomeration of the particles is avoided, the protrusions and flash points are avoided, the visual anti-glare effect is achieved, the micron and nanometer particles can be staggered and orderly distributed, the dispersion uniformity is further improved, the light diffuse reflection is enhanced and uniform, the particles after the grafting serve as reaction monomers and enter the crosslinking polymerization of the polymer, the wear resistance and hardness of the coating are greatly enhanced, and the problem of easy brittle cracking of the surface of the traditional anti-glare film is overcome.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical film, in particular to a fluorene-containing anti-glare coating and a preparation method thereof, an anti-glare film and a polarizer comprising a fluorene-containing anti-glare coating layer. BACKGROUND

[0002] A display module mainly consists of a polarizer and a liquid crystal structure, wherein the polarizer is an indispensable key component in LCD and OLED display. However, when outdoor strong sunlight or indoor lighting light is projected onto the display screen, specular reflection glare is more likely to occur. Therefore, in order to weaken the reflection of ambient light sources and improve the brightness and clarity of the image, it is necessary to make certain treatment on the surface of the display to diffuse the light emitted from the internal light source of the display, while reducing the influence of the normal reflection of the light incident from the outside of the display, and relieving visual fatigue caused by long-term use.

[0003] Therefore, anti-glare films are widely used in display devices to achieve anti-glare and improve display effect by realizing diffuse reflection of incident strong light through the concave-convex microstructure on the surface. Generally, the anti-glare film is obtained by coating an anti-glare coating on the surface of the base film of the polarizer protective film, and then performing photo-curing or thermal curing. However, the anti-glare film often has problems such as surface protrusions, heavy flash points, poor clarity, and the like, which are caused by the influence of the particle size matching and particle distribution uniformity of the diffusion particles, and which greatly affect the display effect of the display screen. For example, in the patent application file with publication number CN115505327B, organic-inorganic composite microspheres are used in combination with an acrylic ester resin with a suitable shrinkage rate to form an anti-glare layer, but the particle distribution is uneven, the abrasion resistance is poor, the hardness is low, and the film surface is prone to brittle fracture. SUMMARY

[0004] In order to solve the problems of uneven particle distribution, heavy flash points, poor abrasion resistance and hardness in the prior art, the present application provides a fluorene-containing anti-glare coating, a preparation method thereof, an anti-glare film and a polarizer.

[0005] To achieve the above-mentioned purpose, the present application is realized by the following technical scheme:

[0006] The present application provides a preparation method of a fluorene-containing anti-glare coating, comprising the following steps:

[0007] S1, under a nitrogen protective atmosphere, 25-30 parts by weight of polyisocyanate, 0.5-0.6 parts by weight of fluorene-modified silicon dioxide-a and 150-200 parts by weight of polytetrahydrofuran diol are added into a reaction container, and pre-polymerization is carried out at 82-88℃ for 2-2.5h, then the temperature is lowered to room temperature, 5-8 parts by weight of hydroxyethyl acrylate is added, and the temperature is raised to 72-74℃ for further reaction for 3-5h;

[0008] S2, 2-6 parts of chain extender, 5-10 parts of methyl methacrylate, 0.2-0.6 parts of fluorenyl modified silica-b, 0.02-0.07 parts of azobisisobutyronitrile are added to the solution after the reaction of step S1 by weight parts, and the chain extension reaction is carried out at 68-73℃ for 2.5-3h;

[0009] S3, after being cooled to room temperature, triethylamine is added and neutralized for 25-35min, then deionized water is added, and high-speed shearing is carried out at 800-1000rpm for 22-26min to obtain a fluorenyl anti-glare coating;

[0010] The fluorenyl modified silica-a in step S1 is prepared from silica with a particle size of 1-5μm, and the fluorenyl modified silica-b in step S2 is prepared from silica with a particle size of 400-600nm.

[0011] Based on the above technical solution, the present application selects two different particle sizes of silica, i.e. micron and nanometer, as the dispersed particles, and carries out fluorenyl grafting modification treatment, and introduces the reaction in the process of pre-polymerization and chain extension, which not only enhances the dispersibility of the particles in the coating substrate, avoids the agglomeration of the particles to produce protrusions and flash points, and achieves the visual effect of anti-glare, but also the micron and nanometer particles can be distributed in an orderly manner, which on the one hand further improves the uniformity of the dispersion, enhances and uniformizes the diffuse reflection of light, and on the other hand, the grafted particles as the reaction monomer enter the crosslinking polymerization of the polymer, which greatly enhances the wear resistance and hardness of the coating, and overcomes the problem of easy brittle cracking of the traditional anti-glare film.

[0012] As a further improvement of the present application, the fluorenyl modified silica-a is prepared by the following method:

[0013] 3-5 parts of γ-aminopropyl triethoxysilane and 5-6 parts of silica with a particle size of 1-5μm are added to 80-100 parts of deionized water by weight parts, and after reaction at 78-82℃ and 100-120rpm for 1-2h, cooling, filtration, rinsing and drying, γ-aminopropyl triethoxysilane grafted silica is obtained;

[0014] According to the weight parts, 3-5 parts of 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene is dissolved into 80-100 parts of toluene solution, and 5-10 parts of the above-mentioned γ-aminopropyl triethoxysilane grafted silica is added, 100-110 mL of toluene solution containing 0.5-0.7% of azobisisobutyronitrile is added at a speed of 20 mL / h under nitrogen protection, and the reaction is carried out at 78-82°C and 20-50 rpm for 13-15 h, and then cooled, filtered, washed and dried to obtain the grafted 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene and γ-aminopropyl triethoxysilane silica, i.e. fluorenyl modified silica-a.

[0015] Based on the above further improved technical solution, the γ-aminopropyl triethoxysilane is used to treat the silica, and the alkoxyl group is hydrolyzed to form a silanol group (Si-OH), which is then dehydrated and condensed with the hydroxyl group on the surface of the silica to form a covalently bonded silicon-oxygen bond (Si-O-Si) grafted to the surface of the silica; then 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene is added, which contains a hydroxyethoxy group (i.e. -OCH2CH2OH) in the molecule, and the hydroxyl group (-OH) therein is a potential active group that can react with the γ-aminopropyl triethoxysilane and the silicon hydroxyl group (Si-OH) on the surface of the silica to be grafted to the surface of the silica. The silica particles treated by grafting contain fluorene groups, which have a certain scattering effect on light, can reduce the intensity of light, thereby reducing the glare phenomenon, and at the same time, can help to improve the wear resistance of the coating.

[0016] As a further improvement of the present application, the preparation of the fluorenyl modified silica-a further includes a silica pretreatment step, which is as follows: silica with a particle size of 1-5 μm is added to a sodium hydroxide solution with a pH of 10-12, anhydrous ethanol is added, and the alkaline etching is carried out at 70-80°C and a rotation speed of 35-45 rpm for 1-2 h, and then filtered, washed and dried at 100-104°C for 10-12 h to obtain the pretreated silica.

[0017] Based on the above further improved technical solution, the alkaline etching of the silica can increase its surface roughness and introduce some surface defects such as vacancies and dangling bonds. These defects usually have high reactivity because they are in an energy unstable state and are easy to react with other substances, which is beneficial to improve the grafting reaction rate in the subsequent process. The addition of ethanol during the process helps to reduce the difference in etching rate caused by different degrees of compactness and improve the etching effect.

[0018] As a further improvement of the present application, the fluorenyl modified silica-b is prepared by the following method:

[0019] According to parts by weight, 3-5 parts of γ-aminopropyl triethoxysilane and 5-6 parts of silica with a particle size of 400-600 nm are added to 80-100 parts of deionized water, and after reaction at a temperature of 78-82℃ and a speed of 100-120 rpm for 1-2 hours, cooling, filtering, washing, and drying, γ-aminopropyl triethoxysilane grafted silica is obtained;

[0020] According to parts by weight, 3-5 parts of 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene are dissolved in 80-100 parts of toluene solution, and 5-10 parts of the above-mentioned γ-aminopropyl triethoxysilane grafted silica is added, 100-110 mL of toluene solution containing 0.5-0.7% of azobisisobutyronitrile is added at a speed of 20 mL / h under nitrogen protection, and the reaction is carried out at a temperature of 78-82℃ and a speed of 20-50 rpm for 13-15 hours, and after cooling, filtering, washing, and drying, silica grafted with 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene and γ-aminopropyl triethoxysilane, i.e. fluorenyl modified silica-b, is obtained. The reaction principle and effect of fluorenyl modification of silica-b refer to the fluorenyl modification of silica-a.

[0021] As a further improvement of the present application, the preparation of the fluorenyl modified silica-b further includes a silica pretreatment step, specifically as follows: silica with a particle size of 400-600 nm is added to a sodium hydroxide solution with a pH of 10-12, anhydrous ethanol is added thereto, and basic etching is carried out at a temperature of 70-80℃ and a speed of 35-45 rpm for 1-2 hours, and after filtering, washing, and drying at a temperature of 100-104℃ for 10-12 hours, pretreated silica is obtained. The principle and effect of basic etching of silica-b refer to the basic etching of silica-a.

[0022] As a further improvement of the present application, in step S1, the polyisocyanate is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate.

[0023] As a further improvement of the present application, in step S2, the chain extender is selected from one or more of 1,4-butanediol, ethylene glycol, propylene glycol, and 1,4-cyclohexanediol.

[0024] To achieve the above-mentioned purpose, the present application further provides a fluorenyl-containing anti-glare coating prepared by the above-mentioned method.

[0025] To achieve the above-mentioned purpose, the present application further provides an anti-glare film comprising a film layer prepared from the above-mentioned fluorenyl-containing anti-glare coating.

[0026] To achieve the above object, the application further provides a polarizing sheet comprising the anti-glare film.

[0027] The application has the beneficial effect that the application provides a fluorene-containing anti-glare coating and a preparation method thereof. In the method, the polyisocyanate and polytetrahydrofuran diol are subjected to prepolymerization to generate a polyurethane prepolymer, then hydroxyethyl acrylate is added to participate in the prepolymerization to generate a polyurethane acrylate prepolymer. During the polyurethane acrylate prepolymerization, large-particle-size fluorene-modified silica-a is added to participate in the reaction with the polyisocyanate and the polyol to enter the prepolymer, then hydroxyethyl acrylate is added, the hydroxyl groups in the hydroxyethyl acrylate react with the unreacted isocyanate groups in the prepolymer, and the C=C double bond in the hydroxyethyl acrylate and the fluorene group are introduced into the polyurethane molecular chain. During the chain extension, small-particle-size fluorene-modified silica-b is added to act as a chain extender under the action of a catalyst to lengthen the molecular chain of the polyurethane acrylate prepolymer, enhance the polymerization and crosslinking thereof, realize staggered and ordered distribution of different particle sizes of the silica, improve the compactness and hardness of the coating, eliminate the flash point, and enhance the adhesion between the coating and the substrate. The anti-glare film and the polarizing sheet prepared from the fluorene-containing anti-glare coating have excellent hardness, adhesion, wear resistance, and display effect. DETAILED DESCRIPTION

[0028] For the purpose, technical solutions and advantages of the implementation of the present application to be clearer, the specific embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0029] Embodiment 1

[0030] Preparation of fluorene-modified silica-a:

[0031] 3 parts of γ-aminopropyl triethoxysilane and 5 parts of silica with a particle size of 1 μm are added to 80 parts of deionized water, and after reaction at a temperature of 78℃ and 100 rpm for 1 h, cooling, filtration, rinsing and drying are performed to obtain silica grafted with γ-aminopropyl triethoxysilane;

[0032] By weight parts, 3 parts of 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene is dissolved into 80 parts of toluene solution, and 5 parts of the above γ-aminopropyl triethoxysilane grafted silica is added, 100 mL of toluene solution containing 0.5% azobisisobutyronitrile is added at a speed of 20 mL / h under nitrogen protection, and the reaction is carried out at 78℃, 20 rpm for 13 h, cooled, filtered, washed, and dried to obtain the silica grafted with 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene and γ-aminopropyl triethoxysilane, that is, fluorenyl modified silica-a.

[0033] Preparation of fluorenyl modified silica-b:

[0034] By weight parts, 3 parts of 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene is dissolved into 80 parts of toluene solution, and 5 parts of the above γ-aminopropyl triethoxysilane grafted silica is added, 100 mL of toluene solution containing 0.5% azobisisobutyronitrile is added at a speed of 20 mL / h under nitrogen protection, and the reaction is carried out at 78℃, 20 rpm for 13 h, cooled, filtered, washed, and dried to obtain the silica grafted with 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene and γ-aminopropyl triethoxysilane, that is, fluorenyl modified silica-a.

[0035] By weight parts, 3 parts of 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene is dissolved into 80 parts of toluene solution, and 5 parts of the above γ-aminopropyl triethoxysilane grafted silica is added, 100 mL of toluene solution containing 0.5% azobisisobutyronitrile is added at a speed of 20 mL / h under nitrogen protection, and the reaction is carried out at 78℃, 20 rpm for 13 h, cooled, filtered, washed, and dried to obtain the silica grafted with 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene and γ-aminopropyl triethoxysilane, that is, fluorenyl modified silica-a.

[0036] The preparation method of the fluorenyl-containing anti-glare coating includes the following steps:

[0037] S1, under the protection of nitrogen atmosphere, by weight parts, 25 parts of toluene diisocyanate, 0.5 parts of fluorenyl modified silica-a, 150 parts of polytetrahydrofuran diol are added into the reaction container, and the prepolymerization is carried out at 82℃ for 2 h, then cooled to room temperature, and 5 parts of hydroxyethyl acrylate is added, and the reaction is carried out at 72℃ for 3 h again;

[0038] S2, by weight parts, 2 parts of 1,4-butanediol, 5 parts of methyl methacrylate, 0.2 parts of fluorenyl modified silica-b, and 0.02 parts of azobisisobutyronitrile are added into the solution after the reaction of step S1, and the chain extension reaction is carried out at 68℃ for 2.5 h;

[0039] S3, cooled to room temperature, added with triethylamine for 25 min, then added with deionized water, and high-speed shearing is carried out at 800 rpm for 22 min to obtain the fluorenyl-containing anti-glare coating.

[0040] Example 2

[0041] Preparation of fluorenyl-modified silica-a:

[0042] Into 90 parts of deionized water, 4 parts of γ-aminopropyl triethoxysilane and 5 parts of silica with a particle size of 3 μm were added, and after reaction at a temperature of 79 °C and 105 rpm for 1.2 h, cooling, filtration, rinsing and drying were performed to obtain γ-aminopropyl triethoxysilane grafted silica;

[0043] Into 90 parts of toluene solution, 4 parts of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene were dissolved, and 6 parts of the above-mentioned γ-aminopropyl triethoxysilane grafted silica was added. Under nitrogen protection, 105 mL of toluene solution containing 0.6% azobisisobutyronitrile was added at a speed of 20 mL / h, and reaction was performed at 79 °C and 25 rpm for 14 h. After cooling, filtration, rinsing and drying, silica grafted with 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene and γ-aminopropyl triethoxysilane, i.e. fluorenyl-modified silica-a, was obtained.

[0044] Preparation of fluorenyl-modified silica-b:

[0045] Into 90 parts of deionized water, 4 parts of γ-aminopropyl triethoxysilane and 5 parts of silica with a particle size of 500 nm were added, and after reaction at a temperature of 79 °C and 105 rpm for 1.2 h, cooling, filtration, rinsing and drying were performed to obtain γ-aminopropyl triethoxysilane grafted silica;

[0046] Into 90 parts of toluene solution, 4 parts of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene were dissolved, and 6 parts of the above-mentioned γ-aminopropyl triethoxysilane grafted silica was added. Under nitrogen protection, 105 mL of toluene solution containing 0.6% azobisisobutyronitrile was added at a speed of 20 mL / h, and reaction was performed at 79 °C and 25 rpm for 14 h. After cooling, filtration, rinsing and drying, silica grafted with 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene and γ-aminopropyl triethoxysilane, i.e. fluorenyl-modified silica-b, was obtained.

[0047] The preparation method of the fluorenyl-containing anti-glare coating comprises the following steps:

[0048] S1, under a nitrogen protection atmosphere, 28 parts of toluene diisocyanate, 0.6 parts of fluorenyl-modified silica-a and 160 parts of polytetrahydrofuran glycol were added into a reaction container, and after pre-polymerization reaction at 83 °C for 2.2 h, the temperature was lowered to room temperature, and then 6 parts of hydroxyethyl acrylate was added, and the temperature was raised to 73 °C for further reaction for 3.5 h;

[0049] S2, 2.5 parts by weight of 1,4-butanediol, 6 parts by weight of methyl methacrylate, 0.3 parts by weight of fluorenyl-modified silica-b, and 0.03 parts by weight of azobisisobutyronitrile were added to the solution after the reaction of step S1, and chain extension was performed at 69°C for 2.8 hours;

[0050] S3, after being cooled to room temperature, triethylamine was added and neutralized for 25 minutes, deionized water was added, and high-speed shearing was performed at 800 rpm for 22 minutes to obtain a fluorenyl anti-glare coating.

[0051] Example 3

[0052] Preparation of fluorenyl-modified silica-a:

[0053] 5 parts by weight of γ-aminopropyl triethoxysilane and 6 parts by weight of silica with a particle size of 5 μm were added to 100 parts by weight of deionized water, and after being reacted at 82°C and 120 rpm for 2 hours, cooling, filtration, rinsing, and drying were performed to obtain γ-aminopropyl triethoxysilane-grafted silica.

[0054] 5 parts by weight of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene were dissolved in 100 parts by weight of toluene solution, and 10 parts by weight of the above-mentioned γ-aminopropyl triethoxysilane-grafted silica was added, 110 mL of a toluene solution containing 0.7% azobisisobutyronitrile was added at a rate of 20 mL / h under nitrogen protection, and reaction was performed at 82°C and 50 rpm for 15 hours, after which cooling, filtration, rinsing, and drying were performed to obtain silica grafted with 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene and γ-aminopropyl triethoxysilane, i.e., fluorenyl-modified silica-a.

[0055] Preparation of fluorenyl-modified silica-b:

[0056] 5 parts by weight of γ-aminopropyl triethoxysilane and 6 parts by weight of silica with a particle size of 600 nm were added to 100 parts by weight of deionized water, and after being reacted at 82°C and 120 rpm for 2 hours, cooling, filtration, rinsing, and drying were performed to obtain γ-aminopropyl triethoxysilane-grafted silica.

[0057] 5 parts by weight of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene were dissolved in 100 parts by weight of toluene solution, and 10 parts by weight of the above-mentioned γ-aminopropyl triethoxysilane-grafted silica was added, 110 mL of a toluene solution containing 0.7% azobisisobutyronitrile was added at a rate of 20 mL / h under nitrogen protection, and reaction was performed at 82°C and 50 rpm for 15 hours, after which cooling, filtration, rinsing, and drying were performed to obtain silica grafted with 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene and γ-aminopropyl triethoxysilane, i.e., fluorenyl-modified silica-b.

[0058] A method for preparing a fluorene-containing anti-glare coating, comprising the following steps:

[0059] S1, under a nitrogen protective atmosphere, 30 parts of toluene diisocyanate, 0.6 parts of fluorene-modified silica-a, 200 parts of polytetrahydrofuran glycol were added into a reaction container, and pre-polymerization was carried out at 88°C for 2.5h, then it was cooled to room temperature, 8 parts of hydroxyethyl acrylate was added, and the temperature was raised to 74°C for further reaction for 5h;

[0060] S2, according to the weight parts, 6 parts of 1,4-butanediol, 10 parts of methyl methacrylate, 0.6 parts of fluorene-modified silica-b, and 0.07 parts of azobisisobutyronitrile were added into the solution after step S1 reaction, and chain extension reaction was carried out at 73°C for 3h;

[0061] S3, after cooling to room temperature, triethylamine was added for neutralization for 35min, then deionized water was added, and high-speed shearing was carried out at 1000rpm for 26min to obtain a fluorene-containing anti-glare coating.

[0062] Example 4

[0063] The difference between this embodiment and example 3 is that,

[0064] 1) Before the preparation of fluorene-modified silica-a, a pretreatment step of silica was included: silica with a particle size of 5μm was added into a sodium hydroxide solution with a pH of 12, anhydrous ethanol was added, alkaline etching was carried out at 80°C and a rotation speed of 45rpm for 2h, then it was filtered, washed, and dried at 104°C for 12h to obtain pretreated silica.

[0065] 2) Before the preparation of fluorene-modified silica-b, a pretreatment step of silica was included: silica with a particle size of 600nm was added into a sodium hydroxide solution with a pH of 12, anhydrous ethanol was added, alkaline etching was carried out at 80°C and a rotation speed of 45rpm for 2h, then it was filtered, washed, and dried at 104°C for 12h to obtain pretreated silica.

[0066] Example 5

[0067] The difference between this embodiment and example 3 is that,

[0068] 1) Before the preparation of fluorene-modified silica-a, a pretreatment step of silica was included: silica with a particle size of 5μm was added into a sodium hydroxide solution with a pH of 10, anhydrous ethanol was added, alkaline etching was carried out at 70°C and a rotation speed of 35rpm for 1h, then it was filtered, washed, and dried at 100°C for 10h to obtain pretreated silica.

[0069] 2) The preparation of fluorenyl-modified silica-b also includes a pretreatment step of silica before: the silica with a particle size of 600 nm is added to a sodium hydroxide solution with a pH of 10, anhydrous ethanol is added thereto, basic etching is carried out at 70°C and a rotation speed of 35 rpm for 1 h, filtration, washing, and drying at 100°C for 10 h to obtain pretreated silica.

[0070] Example 6

[0071] The difference between this example and Example 3 is that,

[0072] 1) The preparation of fluorenyl-modified silica-a also includes a pretreatment step of silica before: the silica with a particle size of 5 μm is added to a sodium hydroxide solution with a pH of 11, anhydrous ethanol is added thereto, basic etching is carried out at 72°C and a rotation speed of 36 rpm for 1.5 h, filtration, washing, and drying at 102°C for 11 h to obtain pretreated silica;

[0073] 2) The preparation of fluorenyl-modified silica-b also includes a pretreatment step of silica before: the silica with a particle size of 600 nm is added to a sodium hydroxide solution with a pH of 11, anhydrous ethanol is added thereto, basic etching is carried out at 72°C and a rotation speed of 36 rpm for 1.5 h, filtration, washing, and drying at 102°C for 11 h to obtain pretreated silica.

[0074] Comparative Example 1

[0075] This comparative example is compared with Example 4, and no fluorenyl modification treatment of silica-a and silica-b is performed.

[0076] Comparative Example 2

[0077] This comparative example is compared with Example 4, and in the preparation of the fluorenyl-containing anti-glare coating, fluorenyl-modified silica-a is used to replace fluorenyl-modified silica-b, that is, the particle size of the silica is all 5 μm.

[0078] Comparative Example 3

[0079] This comparative example is compared with Example 4, and in the preparation of the fluorenyl-containing anti-glare coating, fluorenyl-modified silica-b is used to replace fluorenyl-modified silica-a, that is, the particle size of the silica is all 600 nm.

[0080] Comparative Example 4

[0081] This comparative example is compared with Example 4, and fluorenyl-modified silica-a and fluorenyl-modified silica-b are simultaneously added in the prepolymerization process, and the remaining steps are the same.

[0082] Comparative Example 5

[0083] Comparative Example 2 was the same as Example 4 except that fluorenyl-modified silica-a and fluorenyl-modified silica-b were added simultaneously in the chain extension process.

[0084] The anti-glare coatings obtained from Examples 1-6 and Comparative Examples 1-5 were applied by roll coating on a transparent base layer (80 μm thick) made of polymethyl methacrylate to a dry thickness of 6 μm, then cured by UV irradiation at 280 mJ / cm 2

[0085] Haze:

[0086] The haze value (Haze), total transmittance (T.T) and specular reflectance (Specular) were measured using an NDH2000N Haze meter after the Haze meter was blank calibrated, the sample was cut to appropriate size and put into the sample chamber.

[0087] Gloss:

[0088] The gloss value was measured according to GB / T 9745-2007 "Paints and varnishes - Determination of 20°, 60° and 85° specular gloss of non metallic paint films" using an ETB-0686 gloss meter after calibration. The average value of 8 points at different positions of the sample coating was recorded as the 60° gloss value of the coating.

[0089] Flash point value:

[0090] The flash point value was measured using an SMS-1000 image brightness meter. The sample was attached to the image generator (resolution 326 ppi) and the green light was used as the light source. The flash point value was obtained by dividing the gray scale standard deviation of the filtered image by the average value. The greater the ratio, the more serious the flash point phenomenon.

[0091] Pencil hardness:

[0092] The Elcometer 3086 pencil hardness meter was used. The hardness was H-9H pencil. Five lines were drawn under a load of 500 g. Then the film coating was observed for scratches and judged according to the following criteria:

[0093] ◎: 0-1 scratches;

[0094] X: 2-5 scratches.

[0095] Adhesion:

[0096] ​Scratch Test: Using a cross-hatch cutter, lightly scratch the coating with cross-hatches, then using 3M 600, press and stick to the cross-hatched area, after 5 minutes, tear off the tape, and observe the coating drop-off in the cross-hatched area under a magnifying glass, and judge by the percentage of coating remaining, i.e. 0% if the coating is completely dropped off, and 100% if the coating is completely retained.

[0097] Scratch Resistance:

[0098] Using a reciprocating abrasion tester, apply a load of 500 g / cm2to the sample coating surface and reciprocate 1000 times. Visually observe the degree of damage under a three-color light source:

[0099] ◎: no damage;

[0100] O: a few fine scratches;

[0101] X: entire surface with scratches.

[0102] Cracking:

[0103] According to the bending test of JIS K5600-5-1, wind the sample using a cylindrical mandrel, and according to the cracking generation mode, evaluate according to the following standards.

[0104] ◎: no cracking when winding with an 8 mm mandrel, good effect

[0105] X: cracking when winding with an 8 mm mandrel

[0106] Anti-glare:

[0107] On the back of the sample coating, stick a black acrylic plate, shine the fluorescent light of an LED light source into the surface of the film, and evaluate the blurring of the fluorescent light:

[0108] ◎: the outline of the fluorescent light is completely blurred, good anti-glare;

[0109] O: the outline of the fluorescent light is blurred but retained, ordinary anti-glare;

[0110] X: the outline of the fluorescent light can be clearly seen, poor anti-glare;

[0111] Rainbow:

[0112] Cut the sample into a square shape of 10 cm x 10 cm, lay it flat on the LCD display with the coating facing outward, place a polarizer 10 cm above the sample, observe the rainbow of the sample through the polarizer, and evaluate according to the following standards:

[0113] ◎: no rainbow

[0114] O: very slight rainbow

[0115] X: obvious rainbow

[0116]

[0117] The results are shown in Table 1:

[0118] As can be seen from Table 1, the coating prepared according to the scheme described in Examples 1-6 has appropriate haze, gloss, total light transmittance higher than 90%, pencil hardness reaching 3H, good scratch resistance, and good appearance taste, and no cracks, glare and rainbow stripes are observed.

[0119] Compared with Examples 1-3, the pretreatment step of silica is added in Examples 4-6, the surface active sites of silica are increased, the grafting rate is improved, and the grafting effect is better, so that the coating more easily reaches the desired hardness, adhesion, and scratch resistance.

[0120] In Comparative Example 1, the silica is not grafted and modified by 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene and γ-aminopropyl triethoxysilane, resulting in silica particle agglomeration, poor dispersion, and further resulting in a significant decrease in coating hardness, adhesion, and severe scratches, as well as cracks, poor appearance taste, and obvious rainbow stripes and flashing points.

[0121] In Comparative Example 2, all the silica used has a particle size of 5 μm, the haze is slightly increased, the hardness, adhesion, and scratch resistance are not significantly affected, but the anti-glare property is poor, and slight rainbow stripes appear.

[0122] In Comparative Example 3, all the silica used has a particle size of 600 nm, the haze, total light transmittance, hardness, adhesion, and scratch resistance are not significantly affected, but the anti-glare property is poor, and slight rainbow stripes appear.

[0123] In Comparative Example 4, fluorenyl-modified silica-a and fluorenyl-modified silica-b are simultaneously added in the prepolymerization process, the two particle sizes of silica are not uniformly distributed, and a strong crosslinking network is not formed, resulting in a decrease in coating density, poor hardness and adhesion, cracks, fine scratches, poor anti-glare property, obvious rainbow stripes, and serious flashing points.

[0124] In Comparative Example 5, fluorenyl-modified silica-a and fluorenyl-modified silica-b are simultaneously added in the chain extension process, the interaction force between the components is weakened, the particles are not uniformly distributed, the hardness and adhesion are poor, there are cracks and fine scratches, the anti-glare property is poor, obvious rainbow stripes appear, and the flashing point phenomenon is more serious.

[0125] The embodiments of the present application are described in detail above, but the present application is not limited to the described embodiments. Various changes, modifications, replacements, and variations of the embodiments can be made by those skilled in the art without departing from the principles and spirit of the present application, and still fall within the scope of the present application.

Claims

1. A process for the preparation of a fluorene-based anti-glare coating material, characterized by, It comprises the following steps: S1, under the protection of nitrogen atmosphere, 25-30 parts of polyisocyanate, 0.5-0.6 parts of fluorenyl modified silica-a, 150-200 parts of polytetrahydrofuran glycol are added into the reaction vessel, and the pre-polymerization is carried out at 82-88℃ for 2-2.5h, then cooled to room temperature, and 5-8 parts of hydroxyethyl acrylate is added, and the reaction is carried out at 72-74℃ for 3-5h; S2, according to the weight part, 2-6 parts of chain extender, 5-10 parts of methyl methacrylate, 0.2-0.6 parts of fluorenyl modified silica-b, 0.02-0.07 parts of azobisisobutyronitrile are added into the solution after step S1 reaction, and the chain extension reaction is carried out at 68-73℃ for 2.5-3h; S3, cooled to room temperature, added triethylamine and neutralized for 25-35min, then added deionized water, high speed shearing at 800-1000rpm for 22-26min, to obtain the fluorenyl anti-glare coating; Wherein: the fluorenyl modified silica-a in step S1 is prepared from silica with a particle size of 1-5μm, and the fluorenyl modified silica-b in step S2 is prepared from silica with a particle size of 400-600nm.

2. The preparation method of the fluorenyl anti-glare coating according to claim 1, wherein the fluorenyl modified silica-a is prepared by the following method: According to the weight part, 3-5 parts of γ-aminopropyl triethoxysilane and 5-6 parts of silica with a particle size of 1-5μm are added into 80-100 parts of deionized water, and the reaction is carried out at 78-82℃ and 100-120rpm for 1-2h, then cooled, filtered, washed and dried to obtain γ-aminopropyl triethoxysilane grafted silica; According to the weight part, 3-5 parts of 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene is dissolved in 80-100 parts of toluene solution, and 5-10 parts of the above γ-aminopropyl triethoxysilane grafted silica is added, 100-110mL of toluene solution containing 0.5-0.7% azobisisobutyronitrile is added at a speed of 20mL / h under nitrogen protection, and the reaction is carried out at 78-82℃ and 20-50rpm for 13-15h, then cooled, filtered, washed and dried to obtain silica grafted with 9,9-bis[4-(2-hydroxyethoxy) phenyl] fluorene and γ-aminopropyl triethoxysilane, i.e. fluorenyl modified silica-a. The preparation of the fluorenyl modified silica-a also includes a step of silica pretreatment, which is as follows:

3. The method for preparing a fluorene-based anti-glare paint according to claim 2, characterized by, The silica with a particle size of 1-5μm is added into a sodium hydroxide solution with a pH of 10-12, and anhydrous ethanol is added, and the alkaline etching is carried out at 70-80℃ and 35-45rpm for 1-2h, then filtered, washed and dried at 100-104℃ for 10-12h to obtain the pretreated silica.

4. The preparation method of the fluorenyl anti-glare coating according to claim 1, wherein the fluorenyl modified silica-b is prepared by the following method: ​ ​ According to parts by weight, 3-5 parts of γ-aminopropyl triethoxysilane and 5-6 parts of silica with a particle size of 400-600 nm are added to 80-100 parts of deionized water, and after reaction at a temperature of 78-82°C and a speed of 100-120 rpm for 1-2 hours, cooling, filtration, washing, and drying are performed to obtain γ-aminopropyl triethoxysilane grafted silica; According to parts by weight, 3-5 parts of 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene are dissolved in 80-100 parts of toluene solution, and 5-10 parts of the above-mentioned γ-aminopropyl triethoxysilane grafted silica is added, and under nitrogen protection, 100-110 mL of toluene solution containing 0.5-0.7% of azobisisobutyronitrile is added at a speed of 20 mL / h, and reaction is performed at a temperature of 78-82°C and a speed of 20-50 rpm for 13-15 hours, and cooling, filtration, washing, and drying are performed to obtain silica grafted with 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene and γ-aminopropyl triethoxysilane, i.e., fluorenyl-modified silica-b.

5. The method for preparing the fluorene-containing anti-glare coating according to claim 4, characterized in that, Before preparing the fluorenyl-modified silica-b, a step of silica pretreatment is further included, and specifically as follows: Silica with a particle size of 400-600 nm is added to a sodium hydroxide solution with a pH of 10-12, and anhydrous ethanol is added thereto, and alkaline etching is performed at a temperature of 70-80°C and a speed of 35-45 rpm for 1-2 hours, and filtration, washing, and drying at a temperature of 100-104°C for 10-12 hours are performed to obtain pretreated silica.

6. The method for preparing the fluorene-containing anti-glare coating according to claim 1, characterized in that, In step S1, the polyisocyanate is selected from one or more of toluene diisocyanate, diphenylmethane diisocyanate, and isophorone diisocyanate.

7. The method for preparing the fluorene-containing anti-glare coating according to claim 1, characterized in that, In step S2, the chain extender is selected from one or more of 1,4-butanediol, ethylene glycol, propylene glycol, and 1,4-cyclohexanediol.

8. An anti-glare coating comprising fluorene groups, characterized in that, The fluorenyl-containing anti-glare coating is prepared by the method of any one of claims 1-7.

9. An anti-glare film characterized by, The anti-glare film comprises a film layer prepared from the fluorenyl-containing anti-glare coating of claim 8.

10. A polarizing sheet characterized by comprising: The polarizing sheet comprises the anti-glare film of claim 9.

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