Anti-glare film, polarizing plate, display device, and method for producing anti-glare film

Abstract

The present invention provides an anti-glare film, a polarizing plate, a display device, and a method for manufacturing the anti-glare film, the anti-glare film comprising a transparent substrate and an anti-glare layer formed on at least one surface of the transparent substrate, the anti-glare layer being formed of a UV-curable resin, a thermosetting resin, or a mixture of both, the thermosetting resin at least comprises high-functional polyurethane acrylic resin, low-functional polyurethane acrylic resin and colorant. The anti-dazzle film can effectively weaken the poor visual experience of yellowing, darkening and the like of the display device under the front view condition, and is high in anti-dazzle performance.

Description

Technical Field

[0001] The invention relates to the field of display and optical film materials, and in particular to an anti-glare film, a polarizing plate, a display device and a method for preparing the anti-glare film. Background Art

[0002] Liquid crystal display devices have the characteristics of power saving, light weight, and thinness. They are the mainstream display solutions in the current display industry. In liquid crystal display devices, polarizers are generally configured on the image display side. In order to avoid damage to the polarizer during operation, its surface is usually required to have a certain hardness. At the same time, it prevents unnecessary mirror reflection and improves visual recognition. Generally, an anti-glare function needs to be added to the polarizer protective film. This is the anti-glare film often mentioned in the industry for use on polarizers. The common manufacturing method of anti-glare film is to coat a resin mixture mixed with particles on a transparent substrate, and form an anti-glare film on at least one side of the transparent substrate through curing processes such as baking and light irradiation. The particles will form a fine concave-convex distribution on the surface of the anti-glare layer, thereby preventing mirror reflection on the surface of the film layer to obtain a better scattering anti-glare effect. However, in the solution that uses particles to achieve an anti-glare effect, the greater the refractive index difference between the particle material and the transparent substrate, the higher the haze value and the better the light scattering effect. However, as the internal haze increases, short-wavelength light is scattered toward a wide angle. Therefore, when the display device is viewed at a normal viewing angle, the overall picture gives a yellowish and dark visual experience, with poor visual recognition and reduced overall transparency.

[0003] In summary, the industry is in urgent need of developing an anti-glare film that can effectively reduce the yellowing and darkening of the display device when viewed straight on, and improve the transparency of the anti-glare film, while ensuring high anti-glare effect and transparency. Therefore, the present application proposes an anti-glare film, a polarizing plate, a display device, and a method for preparing the anti-glare film. Summary of the invention

[0004] The purpose of the present invention is to provide an anti-glare film, a polarizer, a display device and a method for preparing the anti-glare film in view of the deficiencies of the prior art. The anti-glare film, the polarizer, the display device and the method for preparing the anti-glare film can well solve the above problems.

[0005] In order to achieve the above requirements, the technical solution adopted by the present invention is: to provide an anti-glare film, a polarizer, a display device and a method for preparing the anti-glare film, the anti-glare film, the polarizer, the display device and a method for preparing the anti-glare film.

[0006] Provided is an anti-glare film, wherein the absolute value of the transmission chromaticity of the anti-glare film is less than 2, and the haze is greater than or equal to 25%.

[0007] Preferably, the anti-glare film comprises a transparent substrate and an anti-glare layer formed on at least one side of the transparent substrate, wherein the anti-glare layer is formed by a UV curable resin, a thermosetting resin or a mixture of the two, and the thermosetting resin contains at least high- and low-functional polyurethane acrylic resins and a colorant.

[0008] Preferably, the haze of the anti-glare film is 25% to 85%.

[0009] Preferably, the colorant of the anti-glare film is an absorption powder having an absorption peak in the wavelength range of 570-590 nm.

[0010] Preferably, the absolute value of the transmission chromaticity of the anti-glare film is 1 or less.

[0011] Preferably, the colorant of the anti-glare film is an absorption powder having an absorption peak in the wavelength range of 580 nm.

[0012] Preferably, the transparent substrate of the anti-glare film is an amorphous olefin polymer film having an alicyclic structure or a triacetyl cellulose cellulose resin.

[0013] Preferably, the anti-glare film contains anti-glare particles, and the anti-glare particle material is inorganic particles or organic particles or a combination of inorganic particles and organic particles.

[0014] Preferably, the UV curable resin is a resin having an acrylate functional group.

[0015] A method for preparing an anti-glare film is provided, comprising the following steps:

[0016] S1: uniformly mixing the glue, anti-glare particles, solvent and colorant used for the anti-glare film to form a coating liquid;

[0017] S2: evenly apply the coating liquid on the substrate;

[0018] S3: The substrate coated with the wet film is conveyed to a heating device for drying.

[0019] Provided is a polarizing plate using any of the above-mentioned anti-glare films.

[0020] A display device is provided, using any one of the above-mentioned anti-glare films.

[0021] The advantages of the invention are as follows:

[0022] The anti-glare film can effectively reduce the bad visual experience of the display device such as yellowing and darkening when viewed straight on, and has high anti-glare properties. DETAILED DESCRIPTION

[0024] In the following description, references to "one embodiment", "an embodiment", "an example", "an example", etc. indicate that the embodiment or example described in this way may include specific features, structures, characteristics, properties, elements or limitations, but not every embodiment or example necessarily includes the specific features, structures, characteristics, properties, elements or limitations. In addition, repeated use of the phrase "according to one embodiment of the present application" may refer to the same embodiment, but does not necessarily refer to the same embodiment.

[0025] For the sake of simplicity, certain technical features well known to those skilled in the art are omitted in the following description.

[0026] According to one embodiment of the present application, the present invention provides an anti-glare film and a method for making the same. The anti-glare film can be used in image devices such as liquid crystal display devices (LCDs) and organic light emitting diodes (OLEDs), and effectively improves the transparency while providing high anti-glare performance, and improves the yellowing and darkening of the display device when viewed straight on. The anti-glare film has an absolute value of a transmission chromaticity b* of less than 2 and a haze of more than 25%. The anti-glare film includes a transparent substrate and an anti-glare layer formed on at least one side of the transparent substrate, and the method for making the anti-glare film is as follows:

[0027] Particles and special colorants are doped into a specific glue system and coated on a transparent substrate to form an anti-glare coating, which is formed into a film after a baking process. Some of the particles protrude from the surface of the film to form an uneven structure, while the other part is suspended in the coating. Specifically, the glue, anti-glare particles, solvent, colorant and other components used in the anti-glare film need to be uniformly mixed first, which can be done using a disperser, paint shaker, magnetic stirrer, bead mill, kneader, mixer and other known devices. Then the uniformly mixed coating liquid is uniformly coated on the substrate. The coating method is not particularly limited, and can be a known method such as spin coating, dipping, spraying, die coating, rod coating, roller coating, screen printing, droplet coating, etc.; then, the material coated with the wet film state is transferred to the heating demand, and the wet film is dried by a known drying method to evaporate the residual solvent. At the same time, the distribution state of the anti-glare particles can be adjusted by selecting factors such as the relative evaporation rate of the solvent, the solid component concentration, the coating liquid temperature, the drying temperature, the drying wind speed, the drying time, the solvent atmosphere concentration in the drying area, etc.; through the above steps, the specific distribution state of the anti-glare particles in the anti-glare layer can be obtained, and the anti-glare particles can be partially exposed on the surface of the film layer, or can be partially or completely hidden in the film layer.

[0028] According to one embodiment of the present application, the absolute value of the transmittance chromaticity b* of the anti-glare film is preferably less than 2, and further preferably less than 1; the haze of the anti-glare film is preferably 25% to 85%; the anti-glare layer can be formed by UV curing type, thermosetting resin or a mixture of the two, and in particular, a specific colorant is added to the resin. The colorant is an absorption powder with an absorption peak in the wavelength range of 570-590nm, and the maximum absorption peak wavelength is preferably 580nm. The colorant can also be a solvent-based universal color paste, which refers to a universal color paste that can be used for most solvent-based coatings, and the carrier resin used is often divided into aldehyde-ketone resin and acrylic resin. Aldehyde-ketone resin has better miscibility and pigment addition, and is still the preferred carrier resin; acrylic resin has better weather resistance, but slightly worse miscibility.

[0029] According to one embodiment of the present application, the substrate used for the anti-glare film is, but not limited to, a light-transmitting substrate, which is limited to a substrate with smoothness, heat resistance and excellent mechanical properties. The specific light-transmitting substrate can be polyester (polyethylene terephthalate, polyethylene naphthalate), cellulose triacetate, cellulose diacetate, cellulose acetate butyrate, polyester, polyamide, polyimide, polyether sulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal, polyether ketone, polymethyl methacrylate, polycarbonate or polyurethane and other thermoplastic resins, preferably polyester (polyethylene terephthalate, polyethylene naphthalate), cellulose triacetate;

[0030] According to one embodiment of the present application, the light-transmitting substrate may be an amorphous olefin polymer (cycloolefin polymer: COP) film having an alicyclic structure. The light-transmitting substrate may also be triacetyl cellulose, also known as triacetyl cellulose "TAC" or other cellulose-based resins, such as cellulose-based resins such as nitrocellulose, acetyl cellulose, cellulose acetate propionate, ethyl hydroxyethyl cellulose, and the like.

[0031] According to one embodiment of the present application, the glue material used in the anti-glare film is, but not limited to, a curable resin, wherein "resin" is a concept including resin components such as monomers and oligomers, preferably a transparent resin, such as a UV curable resin, a thermosetting resin, or a mixture of the two, preferably a UV curable resin. Furthermore, the UV curable resin can be a resin having an acrylate functional group, such as an oligomer or prepolymer of (meth)acrylates of multifunctional compounds such as polyester resins, polyether resins, acrylic resins, epoxy resins, polyurethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, polythiol polyene resins, polyols, etc., having a relatively low molecular weight, and a reactive diluent. Specific examples thereof include monofunctional monomers and multifunctional monomers such as ethyl (meth)acrylate, ethylhexyl (meth)acrylate, styrene, methylstyrene, N-vinyl pyrrolidone, such as polyhydroxymethylpropane tri(meth)acrylate, hexanediol (meth)acrylate, tripropylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, and the like.

[0032] According to one embodiment of the present application, the particle material used in the anti-glare film is inorganic particles or organic particles, or a combination of inorganic particles and organic particles, but not limited to, the inorganic particles are preferably silicon dioxide, and the organic particles are preferably particles composed of at least one material in the group consisting of acrylic resin, polystyrene resin, styrene-acrylic acid copolymer, polyethylene resin, epoxy resin, silicone resin, polyvinylidene fluoride resin and polyvinyl fluoride resin. Among them, styrene-acrylic acid copolymer particles are preferably used.

[0033] Embodiment 1:

[0034] A solution was prepared by uniformly mixing and dispersing 24 parts by weight of high-functional polyurethane acrylate (571, Double Bond Chemical Co., Ltd.), 6 parts by weight of low-functional polyurethane acrylate (UA-4200, Shin-Nakamura Chemical Co., Ltd.), 20 parts by weight of butanone, 45 parts by weight of propylene glycol methyl ether, 2.5 parts by weight of silica particles (SPB-00, Fuji Chemical Co., Ltd.), 0.15 parts by weight of colorant (VL 580-2, Jiangxi Lotte Chemical Co., Ltd.), 0.1 parts by weight of leveling agent (BYK-333, BYK Chemical) and 1.5 parts by weight of photoinitiator (Doublecure184, Double Bond Chemical Co., Ltd.).

[0035] The solution was cast onto a 60 μm TAC base film using a wire rod, and then placed in an oven at 80°C for 1 minute to evaporate the solvent, forming a coating with a thickness of about 3 μm. The coating was then irradiated with ultraviolet light for about 5 seconds using a high-pressure mercury lamp (with a cumulative light intensity of about 250 mJ / cm2), and the coating was cured by ultraviolet light to obtain an anti-glare film.

[0036] In this embodiment, the haze is 50%, and the b value is 1.51.

[0037] Embodiment 2:

[0038] The colorant (VL 580-2, Jiangxi Lotte Chemical Co., Ltd.) in Example 1 was adjusted to 0.30 parts by weight, and the rest was the same as above;

[0039] In this embodiment, the haze is 50%, and the b value is 0.56.

[0040] Embodiment 3:

[0041] The amount of silica particles (SPB-00, Fuji Chemical Co., Ltd.) in Example 1 was adjusted to 1.5 parts by weight, and the rest was the same as above;

[0042] In this embodiment, the haze is 30%, and the b value is 0.62.

[0043] Embodiment 4:

[0044] The amount of silica particles (SPB-00, Fuji Chemical Co., Ltd.) in Example 1 was adjusted to 3.5 parts by weight, and the rest was the same as above;

[0045] In this embodiment, the haze is 85%, and the b value is 1.91.

[0046] Comparative Example 1:

[0047] 24 parts by weight of high-functional polyurethane acrylate (571, Double Bond Chemical Co., Ltd.), 6 parts by weight of low-functional polyurethane acrylate (571, Double Bond Chemical Co., Ltd.), 20 parts by weight of butanone, 45 parts by weight of propylene glycol methyl ether, 2.5 parts by weight of silica particles (SPB-00, Fuji Chemical Co., Ltd.), 0.1 parts by weight of leveling agent (BYK-333, BYK Chemical) and 1.5 parts by weight of photoinitiator (Doublecure 184, Double Bond Chemical Co., Ltd.) were mixed and dispersed uniformly to prepare a solution.

[0048] The solution was cast onto a 60 μm TAC base film using a wire rod, and then placed in an oven at 80°C for 1 minute to evaporate the solvent, forming a coating with a thickness of about 3 μm. The coating was then irradiated with ultraviolet light for about 5 seconds using a high-pressure mercury lamp (with a cumulative light intensity of about 250 mJ / cm2), and the coating was cured by ultraviolet light to obtain an anti-glare film.

[0049] This comparative example: haze 50%, b value 2.56 (high hardness, but shrinkage leads to serious MD lines on the film surface).

[0050] Comparative Example 2:

[0051] The amount of silica particles (SPB-00, Fuji Chemical Co., Ltd.) in Comparative Example 1 was adjusted to 0.5 parts by weight, and the rest was the same as above;

[0052] This comparative example has a haze of 25% and a b value of 2.39.

[0053] In the above-mentioned embodiments and comparative examples, the haze was measured using a haze meter ("NDH 2000" manufactured by Nippon Denshoku Co., Ltd.) in accordance with JIS K-7105, with the surface having a concave-convex structure facing the light receiving device side; the b value, i.e., the transmittance chromaticity, was measured using a spectrophotometer ("U-3010" manufactured by Hitachi High-Tech Science Co., Ltd.) in accordance with JIS Z8781.

[0054] The following table shows the performance of Examples 1 to 3 and Comparative Examples 1 and 2:

[0055] Haze: Haze was measured using a haze meter ("NDH 2000" manufactured by Nippon Denshoku Co., Ltd.) in accordance with JIS K-7105, with the surface having the concavo-convex structure disposed to face the light receiver side.

[0056] Transmittance chromaticity b*: Measured using a spectrophotometer ("U-3010" manufactured by Hitachi High-Tech Science Co., Ltd.) in accordance with JIS Z8781.

[0057] Anti-glare property: The anti-glare film was pasted on a black PC board, and the reflected image when irradiated with a three-wavelength fluorescent light was confirmed by naked eye and evaluated according to the following criteria, among which:

[0058] ◎: No fluorescent light can be observed at all;

[0059] ○: The outline of the fluorescent lamp is blurred;

[0060] △: The shape of the fluorescent lamp can be seen, but the glare is suppressed.

[0061] Hue: Place the anti-glare film toward a three-wavelength fluorescent lamp, observe the hue of the transmitted light with the naked eye, and evaluate according to the following criteria, where:

[0062] ○: The film is observed through a fluorescent light and is colorless and transparent;

[0063] △: A slight yellow or blue tint is observed;

[0064] ╳: Yellow or blue is clearly observed.

[0065]

[0066]

[0067] The above-mentioned embodiments only represent several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for a person skilled in the art, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the claims.

Claims

1. An anti-glare film, characterized in that: The absolute value of the transmission chromaticity of the anti-glare film is less than 2, and the haze is greater than or equal to 25%.

2. The anti-glare film according to claim 1 is characterized in that: The invention comprises a transparent substrate and an anti-glare layer formed on at least one side of the transparent substrate, wherein the anti-glare layer is composed of a resin, anti-glare particles and a colorant, wherein the resin is formed of a UV curable resin, a thermosetting resin or a mixture of the two, and the resin contains at least a high-functional polyurethane acrylic resin and a low-functional polyurethane acrylic resin.

3. The anti-glare film according to claim 1 is characterized in that: The haze of the anti-glare film is 25% to 85%.

4. The anti-glare film according to claim 2 is characterized in that: The colorant is an absorption powder having an absorption peak in the wavelength range of 570-590nm.

5. The anti-glare film according to claim 1 is characterized in that: The absolute value of the transmission chromaticity of the anti-glare film is 1 or less.

6. The anti-glare film according to claim 4 is characterized in that: The colorant is an absorption powder having an absorption peak in the wavelength range of 580 nm.

7. The anti-glare film according to claim 1 is characterized in that: The transparent substrate is one of PET, TAC, PMMA, COP and PC.

8. A method for preparing an anti-glare film, characterized in that The steps include: S1: uniformly mixing the glue, anti-glare particles, solvent and colorant used for the anti-glare film to form a coating liquid; S2: evenly apply the coating liquid on the substrate; S3: The substrate coated with the wet film is transferred to a heating device for drying to form a film, or the substrate is dried and then cured by UV to form a film.

9. A polarizing plate, characterized in that: The anti-glare film according to any one of claims 1 to 7 is used.

10. A display device, characterized in that: The anti-glare film according to any one of claims 1 to 7 is used.

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