Anti-glare film

Abstract

The present invention provides an anti-glare film comprising a polyester substrate having an average in-plane phase difference < = 1500 nm and an average refractive index (np) of between 1.60 and 1.70, an anti-glare coating layer formed on one side of the polyester substrate, and a first undercoat layer formed between the polyester substrate and the anti-glare coating layer, wherein the first undercoat layer has a first refractive index (n1) between 1.55 and 1.65, and the average refractive index (np) of the polyester substrate is greater than the first refractive index (n1) of the first undercoat layer.

Description

Technical Field

[0001] This invention relates to an anti-glare film for the surface of a polarizing plate on the viewing side of a display, which can reduce the generation of interference rainbow patterns and has high definition and low white fog. Background Technology

[0002] As current display devices such as liquid crystal displays (LCDs), organic light-emitting diode displays (OLEDs), and micro LED displays develop towards higher brightness, thinner and lighter designs, and become more flexible, and as the requirements for display quality increase, the functional optical film structures used in displays have become more complex, and the requirements for optical matching between the various film layers have become more stringent.

[0003] Currently, to provide polarizing plates with better resistance to water vapor penetration and mechanical strength, the protective capability and optical properties of the outer protective film, whether used in linear polarizing plates for LCDs or circular polarizing plates for diode displays, cannot be sacrificed for these benefits. It has been suggested to use polyester films with crystalline properties instead of triacetate cellulose (TAC) films as protective films for polarizing plates. However, polyester films, such as the common polyethylene terephthalate (PET) film, have high crystallinity due to their benzene ring structure and high inherent birefringence after stretching. Therefore, when used as protective films, they can affect the display quality of the monitor, such as causing interference rainbow patterns. To suppress the generation of interference rainbow patterns, polyester films generally need to be polyethylene terephthalate films with an in-plane phase difference (R0) of at least 3000 nm, and anti-glare coatings with high haze or high surface roughness should be used to disrupt the interference of the transmitted light. More preferably, polyethylene terephthalate films with an in-plane phase difference of up to 8000 nm or above should be used to reduce interference from interference rainbow patterns.

[0004] However, high in-plane phase difference polyester films with anti-glare coatings that have high haze or high surface roughness significantly affect the image quality and appearance of the display. Furthermore, to obtain polyester films with extremely high in-plane phase difference values, it is necessary to use polyester films manufactured using a uniaxial or biaxial high elongation process or to use polyester films with a higher thickness (e.g., greater than 100 μm) to achieve the desired display quality. However, birefringent polyester films produced with high elongation often reduce the tensile strength of the film material and cause inconsistent thermal shrinkage ratios in the elongation and width directions, both of which affect the protective properties they provide. When paired with a polarizing layer also manufactured with high elongation, the stress balance of the polarizing plate after lamination must be considered to avoid unexpected stress unevenness patterns or color patches. On the other hand, while increasing the thickness of the polyester film to improve the in-plane phase difference is a more direct approach, it does not align with the current trend of display devices becoming thinner and lighter. Furthermore, if applied to displays with flexible or curved edges, increasing the thickness of the protective layer will alter the overall bending stress distribution of the display, increasing the design difficulty in compatibility with other functional optical film layers.

[0005] Therefore, the present invention provides an anti-glare film for the surface of a polarizer on the viewing side of a display, comprising a polyester substrate having a low in-plane phase difference (R0), such as a polyethylene terephthalate film with R0 < 1500 nm, and the anti-glare film having good anti-interference rainbow effect when applied to the front side of the polarizer. Summary of the Invention

[0006] This invention provides an anti-glare film comprising a polyester substrate having an average in-plane phase difference ≤1500 nm and an average refractive index (n) between 1.60 and 1.70. p The anti-glare coating is formed on one side of the polyester substrate; and a first base coating is formed between the polyester substrate and the anti-glare coating, wherein the first base coating has a first refractive index (n1) between 1.55 and 1.65, and the average refractive index (n) of the polyester substrate is... p The first refractive index (n1) is greater than that of the first base coating.

[0007] One embodiment of the present invention provides an anti-glare film comprising a polyester substrate having an average in-plane phase difference ≤1500 nm and an average refractive index (n) between 1.60 and 1.70. p The anti-glare coating is formed on one side of the polyester substrate, wherein the anti-glare coating comprises an acrylic binder and a plurality of organic microparticles; and a first base coating is formed between the polyester substrate and the anti-glare coating, wherein the first base coating has a first refractive index (n1) between 1.55 and 1.65, and the average refractive index (n) of the polyester substrate is... pThe first refractive index (n1) is greater than that of the first base coating.

[0008] Another embodiment of the present invention provides an anti-glare film comprising a polyester substrate having an average in-plane phase difference ≤1500 nm and an average refractive index (n) between 1.60 and 1.70. p The anti-glare coating is formed on one side of the polyester substrate; and a first base coating is formed between the polyester substrate and the anti-glare coating, wherein the first base coating has a first refractive index (n1) between 1.55 and 1.65, and the average refractive index (n) of the polyester substrate is... p The first refractive index (n1) is greater than that of the first base coating.

[0009] In the anti-glare film of the present invention, the polyester substrate is a uniaxially or biaxially extended polyester film and the birefringence difference (Δn) of the polyester substrate is between 0.003 and 0.015.

[0010] The anti-glare film of the present invention further includes a second base coating layer formed on the polyester substrate on the side opposite to the first base coating layer, wherein the second base coating layer has a second refractive index (n2) between 1.51 and 1.60, and the refractive index of the polyester substrate, the first refractive index n1, and the second refractive index n2 of the second base coating layer satisfy the following relationship: (n p -n1) / (n p -n2)≤0.7 and (n1-n2)≥0.05.

[0011] In one embodiment of the present invention, in an anti-glare coating that is an anti-glare film containing organic particles, the anti-glare coating contains 0.5 to 25 parts by weight of organic microparticles per 100 parts by weight of acrylic binder.

[0012] In one embodiment of the present invention, in an anti-glare coating that is an anti-glare film containing organic particles, the anti-glare coating may further contain 0.5 to 12 parts by weight of silica nanoparticles per 100 parts by weight of acrylic binder.

[0013] In one embodiment of the present invention, in an anti-glare coating that is an anti-glare film containing amorphous silica microparticles, the anti-glare coating contains 2 to 35 parts by weight of amorphous silica microparticles per 100 parts by weight of acrylic binder.

[0014] In one embodiment of the present invention, in an anti-glare coating that is an anti-glare film containing amorphous silica microparticles, the anti-glare coating may further contain 3 to 20 parts by weight of organic microparticles per 100 parts by weight of acrylic binder.

[0015] In another embodiment of the anti-glare film of the present invention, the surface of the anti-glare coating further includes an anti-reflective layer.

[0016] In another embodiment of the anti-glare film of the present invention, the thickness of the anti-reflective layer is between 0.1 μm and 0.3 μm.

[0017] The foregoing summary is intended to provide a simplified overview of this disclosure, enabling the reader to gain a basic understanding of its contents. This summary is not a complete overview of the invention, nor is it intended to identify key elements of the embodiments or define the scope of the invention. Upon reviewing the following description of embodiments, those skilled in the art will readily understand the basic spirit of the invention and the technical means and implementation methods employed. Detailed Implementation

[0018] To make the description of the present invention more detailed and complete, illustrative descriptions of the embodiments and specific examples of the present invention are provided below; however, these are not the only forms of implementing or applying the specific examples of the present invention. The various embodiments disclosed below can be combined or substituted with each other where advantageous, and other embodiments can be added to one embodiment without further description or explanation.

[0019] The advantages, features, and technical methods of the present invention will be more readily understood by referring to exemplary embodiments, and the invention may be implemented in different forms. Therefore, it should not be understood as limited to the embodiments set forth herein. Rather, the embodiments provided will enable this disclosure to more thoroughly and completely convey the scope of the invention to those skilled in the art, and the invention will be defined only by the appended claims.

[0020] Unless otherwise defined, all terms (including technical and scientific terms) and proper nouns used below shall, in substance, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains, and those terms as defined in commonly used dictionaries shall be understood to have the same meaning as the content of the relevant field, and shall not be interpreted in an overly idealized or overly formal sense unless explicitly defined below.

[0021] The anti-glare film disclosed in this invention comprises a polyester substrate with low in-plane phase difference, which can provide the display surface with better resistance to water vapor penetration and mechanical strength. Furthermore, although the anti-glare film of this invention uses a polyester substrate, it still achieves better light transmittance and reduces interface reflection and image light intensity loss, and can avoid interference rainbow patterns caused by image light or ambient light at the interfaces on both sides of the polyester substrate.

[0022] One embodiment of the present invention provides an anti-glare film comprising a polyester substrate having an average in-plane phase difference ≤1500 nm and an average refractive index (n) between 1.60 and 1.70. p The anti-glare coating is formed on one side of the polyester substrate, wherein the anti-glare coating comprises an acrylic binder and a plurality of organic microparticles; and a first base coating is formed between the polyester substrate and the anti-glare coating, wherein the first base coating has a first refractive index (n1) between 1.55 and 1.65, and the average refractive index (n) of the polyester substrate is... p The first refractive index (n1) is greater than that of the first base coating.

[0023] Another embodiment of the present invention provides an anti-glare film comprising a polyester substrate having an average in-plane phase difference ≤1500 nm and an average refractive index (n) between 1.60 and 1.70. p The anti-glare coating is formed on one side of the polyester substrate, wherein the anti-glare coating comprises an acrylic binder and a plurality of amorphous silica particles; and a first base coating is formed between the polyester substrate and the anti-glare coating, wherein the first base coating has a first refractive index (n1) between 1.55 and 1.65, and the average refractive index (n) of the polyester substrate is... p The first refractive index (n1) is greater than that of the first base coating.

[0024] The polyester substrate of the anti-glare film of the present invention has a light transmittance of at least 85%, and different thicknesses of polyester substrate can be used according to the application requirements. The thickness can be between 10 μm and 80 μm, preferably between 20 μm and 80 μm.

[0025] In the anti-glare film of the present invention, the first refractive index n1 of the first base coating of the polyester substrate is less than the average refractive index n of the polyester substrate. p To achieve a lower surface reflectivity. In a preferred embodiment of the anti-glare film of the present invention, the first refractive index n1 of the first base coating is preferably between 1.56 and 1.65.

[0026] The anti-glare film of this invention does not use a polyester substrate with extremely high in-plane phase difference. Although the high haze of the anti-glare coating can reduce the coherence of light passing through the polyester substrate, an anti-glare coating with lower total haze can also be used. In embodiments of this invention, the total haze of the anti-glare coating can be high haze, less than or equal to 50%, less than or equal to 30%, less than or equal to 20%, or not greater than 5%, all of which can have anti-interference rainbow effect. The thickness of the anti-glare coating of the anti-glare film of this invention is between 2 μm and 10 μm, preferably between 5 μm and 9 μm.

[0027] The present invention discloses an anti-glare film containing organic microparticles in its anti-glare layer. These organic microparticles are used at a ratio of 0.5 to 25 parts by weight, preferably between 0.8 and 20 parts by weight, relative to 100 parts by weight of acrylic binder resin. The refractive index of these organic microparticles is between 1.4 and 1.6, and the particle size is between 0.5 μm and 6.0 μm, more preferably between 1.0 μm and 5.5 μm. In the anti-glare film containing organic microparticles in its anti-glare layer of the present invention, organic microparticles with appropriate refractive index and particle size can be selected, and the amount of organic microparticles added can be adjusted to regulate the haze of the anti-glare film, with the haze range being between 1% and 50%. In a preferred embodiment of the anti-glare film of the present invention, when the total haze of the anti-glare film is low, for example, not greater than 10%, it is preferable to use organic microparticles with a smaller particle size, for example, the particle size of the organic microparticles can be between 0.5 µm and 4.0 µm, preferably between 1.0 µm and 3.5 µm. In another preferred embodiment of the anti-glare film of the present invention, when the haze of the anti-glare film is high, for example, above 10%, organic microparticles with a particle size between, for example, 1.0 µm and 6 µm are preferably selected, particularly those between 3.0 µm and 5.5 µm. Suitable organic microparticles are polymethyl methacrylate resin microparticles, polystyrene resin microparticles, styrene-methyl methacrylate copolymer microparticles, polyethylene resin microparticles, epoxy resin microparticles, polysiloxane resin microparticles, polyvinylidene fluoride resin, or polyvinyl fluoride resin microparticles, with polymethyl methacrylate resin microparticles, polystyrene resin microparticles, or styrene-methyl methacrylate copolymer microparticles being preferred.

[0028] The anti-glare film containing organic microparticles in the anti-glare layer of the present invention may further comprise 0.5 to 12 parts by weight, preferably between 0.8 and 10 parts by weight. The applicable silica nanoparticles have an average primary particle size between 5 nm and 150 nm, more preferably between 5 nm and 120 nm, and more preferably between 5 nm and 100 nm. In embodiments of the present invention, the silica nanoparticles may be unmodified or surface-modified silica nanoparticles, wherein the surface-modified silica nanoparticles may be silica nanoparticles modified with siloxanes having alkyl, acryloyl, or epoxy groups.

[0029] The present invention relates to an anti-glare film containing amorphous silica microparticles in its anti-glare layer. The laser-etched average particle size of these amorphous silica microparticles is between 2.0 μm and 10 μm, preferably between 2.0 μm and 8 μm, and the BET specific surface area is between 60 m². 2 / g and 100 m 2 Between / g, preferably between 65 m 2 / g and 90 m2 Between / g. In the anti-glare film of the present invention, the amount of these amorphous silica microparticles used relative to each hundred parts by weight of the acrylic adhesive resin may be between 1 part by weight and 35 parts by weight, preferably between 2 parts by weight and 30 parts by weight.

[0030] In the anti-glare layer of the present invention, the anti-glare film containing amorphous silica microparticles may further comprise a plurality of organic microparticles, wherein the amount of such organic microparticles used is between 5 parts by weight and 25 parts by weight per 100 parts by weight of the acrylic binder resin. Suitable organic microparticles for the anti-glare coating containing amorphous silica microparticles include polymethyl methacrylate resin microparticles, polystyrene resin microparticles, styrene-methyl methacrylate copolymer microparticles, melamine microparticles, polyethylene resin microparticles, epoxy resin microparticles, polysiloxane resin microparticles, polyvinylidene fluoride resin, or polyvinyl fluoride resin microparticles.

[0031] The anti-glare film of the present invention is used for bonding with the display-side polarizing film of a display. Since the polarizing film is generally an extended polyvinyl alcohol film bonded to a polyester substrate with a polyvinyl alcohol adhesive layer, the polyester substrate of the anti-glare film of the present invention further includes a second base coating on the side opposite to the first base coating. The second refractive index n2 of the second base coating is between 1.51 and 1.60, preferably between 1.52 and 1.60, to obtain a lower interfacial reflectivity between the second base coating and the polyester substrate. Simultaneously, it matches the refractive index of the polyvinyl alcohol film and the polyvinyl alcohol adhesive layer, reducing the interfacial reflectivity with the polarizing layer. Furthermore, the second refractive index n2 of the second base coating needs to be less than the first refractive index n1 of the first base coating, i.e., n p >n1>n2, and the ratio of the refractive index difference between the polyester substrate and the undercoat on both sides must satisfy the following relationship: (n p -n1) / (n p -n2)≤0.7, which helps to reduce the interfacial reflectivity on both sides of the polyester substrate and at the same time reduce the occurrence of interference rainbow patterns.

[0032] Given that the average refractive index of the polyester substrate is between approximately 1.60 and 1.70, the refractive index difference between the interfaces of the two sides with air and the polarizing layer is relatively large. Furthermore, due to its birefringence, it easily produces high-intensity coherent light, resulting in interference rainbow patterns. Therefore, if the ratio of the refractive index difference between the polyester substrate and the undercoating layer on both sides does not satisfy the relationship: (n p -n1) / (n p -n2)≤0.7, representing the refractive index difference (n) between the polyester substrate and the first base coating. p If the refractive index of -n1 is too high, the surface reflectivity of the polyester substrate will be high, or the refractive index difference between the polyester substrate and the second base coating will be too high (n pWhen the refractive index (-n2) is too low, it relatively increases the refractive index difference between the polarizing layer and the polyester substrate when bonded to the polarizing layer as a polarizing plate. This reduces the transmittance of image light between the film layers, making it difficult to effectively reduce interference rainbow patterns when using a polyester substrate with an in-plane phase difference of no more than 1500 nm, thus interfering with the image light quality emitted by the display. The anti-glare film of this invention does not use a polyester substrate with an extremely high in-plane phase difference. Although the high haze of the anti-glare coating (e.g., greater than or equal to 80%) can reduce the coherence of light passing through both surfaces of the polyester substrate, an anti-glare coating with lower total haze can also be used. In embodiments of this invention, the total haze of the anti-glare coating can be high, less than or equal to 50%, less than or equal to 30%, less than 20%, or less than or equal to 5%, all of which can have anti-interference rainbow pattern effects without causing image quality degradation or a white fogging appearance on the display due to excessive haze. As the total haze decreases, the anti-glare film of this invention can also achieve better light transmittance, reducing interface reflection and image light intensity loss.

[0033] In a preferred embodiment of the anti-glare film of the present invention, the difference (n1-n2) between the first refractive index n1 of the first base coating of the polyester substrate and the second refractive index n2 of the second base coating is greater than or equal to 0.05, which reduces the coherence of light passing through the interfaces on both sides of the polyester substrate, and makes it less likely for light of different wavelengths to produce interference rainbow patterns due to enhanced interference.

[0034] In the anti-glare film of the present invention, the first base coating of the polyester substrate comprises, but is not limited to, a coating formed of acetalized polyvinyl alcohol, polyurethane, urethane, polyether resin, polyacrylic resin, isocyanate, or a combination thereof, and its refractive index can be increased to a desired range by adding metal oxide particles or benzene ring-containing compounds to the coating. In one embodiment of the anti-glare film of the present invention, the thickness of the first base coating and the second base coating can be between 0.1 μm and 0.3 μm. The base coating within this thickness range can change the refractive index on both sides of the polyester substrate without significantly increasing the thickness of the anti-glare film, thus not affecting the stress distribution when the anti-glare film is applied to a display with flexible or curved edges.

[0035] The polyester substrate of the anti-glare film of this invention is a polyester substrate with an in-plane phase difference of no more than 1500 nm. Because this polyester substrate is not a high in-plane phase difference substrate, it is not necessary to use a polyester film with a high elongation ratio process to increase the birefringence difference (Δn) in the orthogonal elongation direction and width direction. Therefore, the polyester substrate suitable for this invention can be a uniaxially elongated or biaxially elongated polyester film, with a birefringence difference preferably between 0.003 and 0.015, representing a uniaxially elongated or biaxially elongated polyester film with a low in-plane phase difference obtained using a low elongation ratio process. Because the polyester substrate of the anti-glare film of this invention is a polyester film obtained using a low elongation ratio process, it has better tensile strength and a more uniform heat shrinkage ratio in the elongation and width directions. The anti-glare film of the present invention, whether paired with an extended polarizing layer with a high elongation ratio or a coating polarizing layer that does not require elongation, can make the stress distribution of the formed polarizing plate more uniform, provide better protection, and is also conducive to application in flexible display devices.

[0036] In the anti-glare film of the present invention, the second base coating of the polyester substrate may be a coating with easy adhesion to facilitate bonding with the polarizing layer and the polyvinyl alcohol adhesive layer, and have a similar refractive index. For example, a coating may be formed including, but not limited to, acetalized polyvinyl alcohol, polyurethane, urethane, polyether resin, polyacrylic resin, isocyanate or a combination thereof.

[0037] In the anti-glare film of the present invention, the acrylic adhesive resin used in the anti-glare coating comprises a (meth)acrylate composition and an initiator, wherein the (meth)acrylate composition comprises a polyurethane (meth)acrylate oligomer with a functionality of 6 to 15, a (meth)acrylate monomer with a functionality of at least 3 to 6, and a (meth)acrylate monomer with a functionality of at least less than 3, wherein the molecular weight of the polyurethane (meth)acrylate oligomer is between 1,000 and 4,500.

[0038] In a preferred embodiment of the present invention, the (meth)acrylate composition in the acrylic adhesive resin comprises 35 to 50 parts by weight of a polyurethane (meth)acrylate oligomer with a functionality of 6 to 15, 12 to 20 parts by weight of a (meth)acrylate monomer with a functionality of 3 to 6, and 1.5 to 12 parts by weight of a (meth)acrylate monomer with a functionality of less than 3.

[0039] In a preferred embodiment of the present invention, the polyurethane (meth)acrylate oligomer with a functionality of 6 to 15 has a molecular weight of not less than 1,000, preferably between 1,500 and 4,500. In yet another preferred embodiment of the present invention, the polyurethane (meth)acrylate oligomer with a functionality of 6 to 15 is preferably an aliphatic polyurethane (meth)acrylate oligomer with a functionality of 6 to 15.

[0040] In a preferred embodiment of the invention, the (meth)acrylate monomer with a functionality of 3 to 6 has a molecular weight of less than 1,000, more preferably less than 800. Suitable (meth)acrylate monomers with a functionality of 3 to 6 for use in the present invention may be, for example, one or a combination of pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), and dipentaerythritol pentaacrylate (DPPA), but are not limited thereto.

[0041] In a preferred embodiment of the present invention, the (meth)acrylate monomer with a functionality of less than 3 may be a (meth)acrylate monomer having a functionality of 1 or 2 and a molecular weight of less than 500. Suitable (meth)acrylate monomers with a functionality of less than 3 for use in the present invention may be, for example, one or a combination of 1,6-hexanediol diacrylate (HDDA), isobornyl acrylate (IBOA), cyclotrimethylolpropane methyl acetal acrylate (CTFA), and 2-phenoxyethyl acrylate (PHEA).

[0042] Suitable initiators for the acrylic binder resin of the present invention can be those widely known and applicable in this art, and there are no particular limitations. For example, acetophenone initiators, diphenyl ketone initiators, phenylacetone initiators, benzoyl initiators, bifunctional α-hydroxy ketone initiators, or acylphosphine oxide initiators can be used. The aforementioned initiators can be used alone or in combination.

[0043] In other embodiments of the present invention, additives such as antistatic agents, colorants, flame retardants, ultraviolet absorbers, antioxidants, and surface modifiers may also be added to the aforementioned acrylic adhesive resin as needed.

[0044] The anti-glare coating of the present invention can be achieved by coating a polyester substrate with an anti-glare coating liquid. The preparation method of the anti-glare coating liquid includes mixing a polyurethane (meth)acrylate oligomer with a functionality of 6 to 15 in a (meth)acrylate composition, a (meth)acrylate monomer with a functionality of at least 3, a (meth)acrylate monomer with a functionality of at least less than 3, and an initiator with a suitable solvent to form an acrylic binder resin; adding organic microparticles and / or silica nanoparticles and an organic solvent to the acrylic binder resin and mixing them to form an anti-glare coating liquid; applying the anti-glare coating liquid onto a polyester substrate, drying it, and then curing it on the polyester substrate by radiation to form an anti-glare coating to obtain an anti-glare film.

[0045] In another embodiment of the present invention, the anti-glare coating of the anti-glare film may further include optical functional layers such as a hard coating layer and an anti-reflective layer. In an embodiment of the anti-glare film of the present invention, an anti-reflective layer may be further applied to the anti-glare coating to further reduce surface reflectivity and avoid reflecting strong light, and also has a certain leveling property for anti-glare coatings with surface haze, which can make the gloss of the display better.

[0046] The antireflective layer of the present invention comprises a fluorinated and acrylate-modified polysiloxane resin, a plurality of hollow silica nanoparticles, an initiator, and a leveling agent comprising a (meth)acrylamide-modified organosilicon compound having perfluoropolyether functional groups. The reflectivity of this antireflective layer may be less than 1.1%, and preferably not greater than 1.05%. The preparation method of this antireflective coating involves mixing the fluorinated and acrylate-modified polysiloxane resin with nano-silica particles with a particle size between 0.05 µm and 0.3 μm, a suitable initiator, a leveling agent, and an organic solvent, and coating the mixture onto an anti-glare coating to achieve an antireflective effect. The thickness of the antireflective layer is between 0.1 μm and 0.3 μm.

[0047] The solvents used in the aforementioned anti-glare and anti-reflective coatings can be organic solvents widely used in this technical field, such as ketones, aliphatic or alicyclic hydrocarbons, aromatic hydrocarbons, ethers, esters, or alcohols. One or more organic solvents can be used in both anti-glare and anti-reflective coatings. Suitable solvents include, for example, acetone, butanone, cyclohexanone, methyl isobutyl ketone, hexane, cyclohexane, dichloromethane, dichloroethane, toluene, xylene, propylene glycol methyl ether, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, n-butanol, isobutanol, isopropanol, diacetone alcohol, propylene glycol methyl ether acetate, cyclohexanol, or tetrahydrofuran, and their analogues.

[0048] The methods for applying anti-glare coatings and anti-reflective coatings can be respectively adopted, such as roller coating, doctor blade coating, dip coating, roller coating, spin coating, slot coating and other coating methods commonly used in this technical field.

[0049] Another object of the present invention is to provide a polarizing plate having a polarizing element and an anti-glare film as described above.

[0050] The following embodiments are provided to further illustrate the present invention, but the scope of the invention is not limited thereto.

[0051] Example

[0052] Preparation Example 1: Preparation of Acrylic Adhesive Resin

[0053] 42 parts by weight of polyurethane acrylate oligomer (functionality 6, molecular weight approximately 2,600, viscosity approximately 62,000 cps (25°C), purchased from Miwon Specialty Chemical Co., Ltd, Korea), 4.5 parts by weight of pentaerythritol triacrylate (PETA), 12 parts by weight of dipentaerythritol hexaacrylate (DPHA), 3 parts by weight of isobornyl acrylate (IBOA), 4 parts by weight of photoinitiator (Chemcure-481, purchased from Heng Chiao Industry, Taiwan), 24.5 parts by weight of ethyl acetate (EAC), and 10 parts by weight of n-butyl acetate (nBAC) were mixed and stirred for 1 hour to form an acrylate-based adhesive resin.

[0054] Preparation Example 2: Preparation of Anti-glare Coating I

[0055] 220 parts by weight of the acrylate-based adhesive resin prepared in Example 1, 2.3 parts by weight of polymethyl methacrylate microparticles (SSX-102, average particle size 2 μm, refractive index 1.49, purchased from Sekisui Chemicals Co., Ltd., Japan), 15.1 parts by weight of silica nanoparticle dispersion sol (MEK-ST-UP, solid content 20%, solvent: methyl ethyl ketone, purchased from Nissan Chemical, Japan) with an average primary particle size of 9 nm to 15 nm and connected as long chains of 40 nm to 100 nm, 7.5 parts by weight of acrylate-ether-based surfactant (BYK-UV3535, solid content 10%, solvent: ethyl acetate, purchased from BYK, Germany), and 3.1 parts by weight of silica nanoparticle dispersion sol (NanoBYK-3650, average primary particle size 20 nm to 100 nm) were prepared. nm, with a solid content of 31%, and solvents of propylene glycol methyl ether acetate / propylene glycol methyl ether (purchased from BYK, Germany), 64 parts by weight of ethyl acetate (EAC) and 118 parts by weight of n-butyl acetate (nBAC), were mixed and stirred for 1 hour to disperse them evenly, thus forming anti-glare coating liquid I.

[0056] Preparation Example 3: Preparation of Anti-glare Coating II

[0057] 220 parts by weight of the acrylate-based adhesive resin prepared in Example 1, 16.2 parts by weight of methyl methacrylate and styrene copolymer microparticles (XX-49IK, average particle size 5) were prepared. The following ingredients were mixed and stirred for 1 hour to form anti-glare coating liquid II: 4.2 parts by weight of methyl methacrylate and styrene copolymer microparticles (XX-50IK, average particle size 3.5 μm, refractive index 1.545, purchased from Sekisui Chemicals Co., Ltd., Japan), 6.0 parts by weight of polyether modified polydimethylsiloxane leveling agent (BYK-333, solid content 10%, solvent ethyl acetate, purchased from BYK, Germany), 16.4 parts by weight of silica nanoparticle dispersion sol (NanoBYK-3650), 41.2 parts by weight of ethyl acetate (EAC), 82.4 parts by weight of n-propyl acetate (nPAC), and 41.2 parts by weight of propylene glycol methyl ether acetate (PGMEA).

[0058] Preparation Example 4: Preparation of Anti-glare Coating III

[0059] 200 parts by weight of acrylic adhesive resin I and 26 parts by weight of amorphous silica microparticles (Nipsil) were added. ® SS-50F, average particle size 2.2μm, BET specific surface area 85 m² 2 / g, purchased from Tosoh Silicon Chemical Co., Ltd., Japan), 2.2 parts by weight of dispersion (DisperBYK-2150, solid content 5%, solvent is propylene glycol methyl ether acetate and n-butyl acetate, purchased from BYK, Germany), 13 parts by weight of polyether modified polydimethylsiloxane leveling agent (BYK-333), 65 parts by weight of ethyl acetate (EAC) and 160 parts by weight of n-butyl acetate (nBAC), were mixed and stirred evenly to form an anti-glare coating liquid.

[0060] Preparation Example 5: Preparation of Anti-glare Coating IV

[0061] 200 parts by weight of acrylic adhesive resin I and 2.2 parts by weight of amorphous silica microparticles (Nipsil) were added. ® SS-50F), 0.1 parts by weight of dispersion (DisperBYK-2150), 0.3 parts by weight of polyether-modified polydimethylsiloxane leveling agent (BYK-333), 60 parts by weight of ethyl acetate (EAC) and 160 parts by weight of n-butyl acetate (nBAC) are mixed and stirred to form anti-glare coating IV.

[0062] Preparation Example 6: Preparation of Antireflective Layer Solution

[0063] A solution of antireflective layer was formed by mixing and stirring 25.4 parts by weight of fluorinated and acrylate-modified polysiloxane resin (X-12-2430C, purchased from Shigeobushi Chemical Co., Ltd., Japan), 1.6 parts by weight of photoinitiator (KIP-160, purchased from IGM Resin, Netherlands), 103.5 parts by weight of leveling agent of organosilicon compound modified with perfluoropolyether functional group (X-71-1203E, solid content 20%, solvent is methyl ethyl ketone, purchased from Shigeobushi Chemical Co., Ltd., Japan), 211.5 parts by weight of hollow silica nanoparticle dispersion sol (Thrulya 4320, solid content 20%, average particle size 60 nm, solution is methyl isobutyl ketone, purchased from Nichibuki Catalyst Chemical Co., Ltd., Japan), 1772 parts by weight of ethyl acetate (EAC) and 886 parts by weight of propylene glycol methyl ether acetate (PGMEA) for 10 minutes.

[0064] Preparation Example 7: Preparation of Polyethylene Terephthalate Film

[0065] Polyethylene terephthalate (PET) resin raw material particles with a melting point of 250°C to 260°C were heated to a molten state at 280°C. These particles were then extruded using an extruder (model: DNT-EXT01, purchased from JSW, Japan) and cooled to room temperature to form a uniform PET sheet with non-crystalline orientation. This PET sheet was then subjected to longitudinal stretching at 100°C using a dry stretching machine (model: MA-08, purchased from Shin Ying Machinery, Taiwan, China) at an elongation ratio of 3.0 to improve its crystallinity and light transmittance. Subsequently, it was stretched in the width direction at an elongation ratio of 3.0. This resulted in a biaxially stretched PET film with a light transmittance greater than 90%, an average refractive index of 1.66, an in-plane phase difference (R0) of 271 nm, and a thickness of 76 µm. The birefringence difference (Δn) was obtained by dividing the in-plane phase difference by the thickness, yielding a value of 0.004.

[0066] Example 1

[0067] The polyethylene terephthalate film prepared in Preparation Example 7 was used as the polyester substrate. A first base coat was formed by coating both sides with a photocurable acrylic resin (model: FL219, purchased from Yung-Kuan Chemical Co., Ltd.) with a refractive index of 1.61 (n1) and curing it. A second base coat was formed by coating both sides with a photocurable acrylic resin (model: 660G-40L, purchased from Chang Hsing Materials Industry Co., Ltd.) with a refractive index of 1.51 (n2). The anti-glare coating liquid I prepared in Preparation Example 2 was then coated onto the first base coat. After drying, it was cured under nitrogen at 80 mJ / cm². 2UV lamps with a radiation dose are used for photocuring to form an anti-glare coating on a first base layer, thereby obtaining the anti-glare film of the present invention. The refractive index of the base layer, the thickness of the anti-glare coating, the haze of the anti-glare coating, and the interference rainbow pattern of the anti-glare film are measured according to the methods described below. The measurement and evaluation results are listed in Table 1.

[0068] The refractive index of the base coating of the anti-glare film can be measured by bonding both sides of a PET polyester substrate with a first base coating and a second base coating to a black acrylic plate. Using a HITACHI U-4150 spectrophotometer in the wavelength range of 380 nm to 780 nm, the average reflectance of diffuse and specular reflection in SCI mode and the average diffuse reflectance in SCE mode are measured on both sides of the PET polyester substrate. The refractive index of the PET polyester substrate and the thickness of each layer are input into the Spectral Reflectance Calculator (Filmetrics) to calculate the refractive index of the first base coating and the second base coating on both sides of the PET polyester substrate.

[0069] Thickness measurement: The thickness of the anti-glare coating was measured using an electronic comparator Extramess 2001 (Mahr Inc., Germany) according to the description in JISK 5600-1-7:2014.

[0070] Haze measurement: The haze of the anti-glare coating was evaluated using an NDH-2000 (Nippon Denshoku Corp.) according to the description in JIS K7136.

[0071] Evaluation of interference rainbow effect: The anti-glare film was attached to the polarizing layer of the Acer 27” Agile-Splendor IPS XV272K LCD monitor after the protective layer on the display side was removed using transparent optical adhesive. The degree of interference rainbow effect of the anti-glare film on the viewing side polarizing plate of the LCD monitor surface with the anti-glare film attached was evaluated at a 60-degree viewing angle. If there was no obvious interference rainbow effect, it was rated as “excellent” (〇). If interference rainbow effect could be observed, it was rated as “poor” (╳).

[0072] Example 2

[0073] A PET film (model: EBQ-410, purchased from Mitsubishi Chemical Corporation, Japan) with a thickness of 50 µm, an in-plane phase difference of 407 nm, a birefringence difference of 0.008, an average refractive index of 1.66, and having a first undercoat with a refractive index of 1.61 and a second undercoat with a refractive index of 1.56 on both sides of the film surface, was used as the polyester substrate. Following the same method as in Example 1, an anti-glare coating was formed on the first undercoat to obtain the anti-glare film of the present invention.

[0074] The anti-glare film obtained in Example 2 was subjected to the same thickness and haze measurement and interference rainbow pattern evaluation method as in Example 1. The results are listed in Table 1.

[0075] Example 3

[0076] A PET film (model: EBQ-409, purchased from Mitsubishi Chemical Corporation, Japan) with a thickness of 50 µm, an in-plane phase difference of 456 nm, a birefringence difference of 0.009, an average refractive index of 1.66, and having a first undercoat layer with a refractive index of 1.64 and a second undercoat layer with a refractive index of 1.56 on both sides of the film surface, was used as the polyester substrate. Following the same method as in Example 1, an anti-glare coating was formed on the first undercoat layer to obtain the anti-glare film of the present invention.

[0077] The anti-glare film obtained in Example 3 was subjected to the same thickness and haze measurement and interference rainbow pattern evaluation method as in Example 1. The results are listed in Table 1.

[0078] Example 4

[0079] A PET film (model: QBN-0017, purchased from Mitsubishi Chemical Corporation, Japan) with a thickness of 66 µm, an in-plane phase difference of 713 nm, a birefringence difference of 0.011, an average refractive index of 1.66, and having a first undercoat with a refractive index of 1.61 and a second undercoat with a refractive index of 1.54 on both sides of the film surface, was used as the polyester substrate. Following the same method as in Example 1, an anti-glare coating was formed on the first undercoat to obtain the anti-glare film of the present invention.

[0080] The anti-glare film obtained in Example 4 was subjected to the same thickness and haze measurement and interference rainbow pattern evaluation method as in Example 1. The results are listed in Table 1.

[0081] Example 5

[0082] A PET film (model: O700E, purchased from Mitsubishi Chemical Corporation, Japan) with a thickness of 75 µm, an in-plane phase difference of 1080 nm, a birefringence difference of 0.014, an average refractive index of 1.66, and having a first undercoat with a refractive index of 1.65 and a second undercoat with a refractive index of 1.52 on both sides of the film surface, was used as the polyester substrate. The anti-glare coating liquid II prepared in Example 3 was coated onto the first undercoat of the polyester substrate, and after drying, it was incubated under nitrogen at 80 mJ / cm². 2 UV lamps with a radiation dose are used for photocuring to form an anti-glare coating on a first base layer, thereby obtaining the anti-glare film of the present invention.

[0083] The anti-glare film obtained in Example 5 was subjected to the same thickness and haze measurement and interference rainbow pattern evaluation method as in Example 1. The results are listed in Table 1.

[0084] Example 6

[0085] A PET film (model: O700E) with a thickness of 75 µm, an in-plane phase difference of 1080 nm, a birefringence difference of 0.014, an average refractive index of 1.66, and a first undercoat with a refractive index of 1.65 and a second undercoat with a refractive index of 1.52 on both sides of the film surface was used as the polyester substrate. The anti-glare coating liquid III prepared in Example 4 was coated onto the first undercoat of the polyester substrate, and after drying, it was incubated under nitrogen at 80 mJ / cm². 2 UV lamps with radiation doses are used for photocuring to form an anti-glare coating on the first base layer, thereby obtaining an anti-glare film.

[0086] Example 7

[0087] A PET film (model: O700E) with a thickness of 75 µm, an in-plane phase difference of 1080 nm, a birefringence difference of 0.014, an average refractive index of 1.66, and having a first undercoat with a refractive index of 1.65 and a second undercoat with a refractive index of 1.52 on both sides of the film surface was used as the polyester substrate. The anti-glare coating liquid IV prepared in Example 5 was coated onto the first undercoat of the polyester substrate, and after drying, it was incubated under nitrogen at 80 mJ / cm². 2 UV lamps with radiation doses are used for photocuring to form an anti-glare coating on the first base layer, thereby obtaining an anti-glare film.

[0088] Example 8

[0089] The anti-glare film prepared in Example 1 was coated with the anti-reflective layer solution prepared in Example 6. The film after coating with the anti-reflective layer solution was dried in an oven at 80°C and then dried under nitrogen atmosphere at 350 mJ / cm². 2 UV lamps with radiation dose are used for photocuring to obtain an anti-reflective layer with a thickness of about 0.13 μm on the surface of the anti-glare coating, resulting in an anti-reflective and anti-glare film with both an anti-glare coating and an anti-reflective layer while achieving a low surface reflectivity.

[0090] The anti-reflective and anti-glare film obtained in Example 8 was subjected to the same thickness and haze measurement and interference rainbow pattern evaluation method as in Example 1. The results are listed in Table 1.

[0091] Comparative Example 1

[0092] The polyethylene terephthalate film prepared in Example 7 was used as the polyester substrate, and both sides were coated with a photocurable acrylic resin (model: 660G-40L, purchased from Changxing Materials Industry Co., Ltd.) with a refractive index of 1.51, and cured to form two base coatings to obtain a PET protective film. The anti-glare coating liquid I prepared in Example 2 was then coated onto one of the base coatings, dried, and then cured under nitrogen at 80 mJ / cm².2 UV lamps with radiation doses are used for photocuring to form an anti-glare coating on a base layer, thereby obtaining an anti-glare film.

[0093] The anti-glare film prepared in Comparative Example 1 was subjected to the same thickness, haze measurement and interference rainbow pattern evaluation method as in Example 1, and the results are listed in Table 2.

[0094] Comparative Example 2

[0095] A PET film (model: QBN-0015, purchased from Mitsubishi Chemical Corporation, Japan) with a thickness of 52 µm, an in-plane phase difference of 974 nm, a birefringence difference of 0.019, an average refractive index of 1.66, and having a first undercoat with a refractive index of 1.56 and a second undercoat with a refractive index of 1.55 on both sides of the film surface, was used as the polyester substrate. The anti-glare coating liquid I prepared in Example 2 was coated onto the first undercoat and dried. Then, it was subjected to nitrogen atmosphere at 80 mJ / cm². 2 UV lamps with radiation doses are used to cure the polyester substrate, forming an anti-glare layer to prepare an anti-glare film.

[0096] The anti-glare film prepared in Comparative Example 2 was subjected to the same thickness, haze measurement and interference rainbow ripple evaluation methods as in Example 1, and the results are listed in Table 2.

[0097] Comparative Example 3

[0098] A PET film (model: QBN-0015, purchased from Mitsubishi Chemical Corporation, Japan) with a thickness of 75 µm, an in-plane phase difference of 2384 nm, a birefringence difference of 0.032, an average refractive index of 1.66, and having a first undercoat with a refractive index of 1.64 and a second undercoat with a refractive index of 1.59 on both sides of the film surface, was used as the polyester substrate. Following the same method as Comparative Example 2, the anti-glare coating liquid I prepared in Example 2 was applied onto the first undercoat to form an anti-glare layer to prepare the anti-glare film.

[0099] The anti-glare film prepared in Comparative Example 3 was subjected to the same thickness, haze measurement and interference rainbow ripple evaluation method as in Example 1. The results are listed in Table 2.

[0100] Comparative Example 4

[0101] A PET film (model: QBN-0012, purchased from Mitsubishi Chemical Corporation, Japan) with a thickness of 75 µm, an in-plane phase difference of 2490 nm, a birefringence difference of 0.033, an average refractive index of 1.66, and having a first undercoat with a refractive index of 1.61 and a second undercoat with a refractive index of 1.59 on both sides of the film surface, was used as the polyester substrate. Following the same method as Comparative Example 2, the anti-glare coating liquid I prepared in Example 2 was applied onto the first undercoat to form an anti-glare layer to prepare the anti-glare film.

[0102] The anti-glare film prepared in Comparative Example 4 was subjected to the same thickness, haze measurement and interference rainbow ripple evaluation methods as in Example 1. The results are listed in Table 2.

[0103] Table 1. Measurement values ​​and optical detection results for Examples 1 to 6

[0104]

[0105] Table 2. Measurement values ​​and optical detection results of Comparative Examples 1 to 4

[0106]

[0107] The test results in Tables 1 and 2 show that the in-plane phase difference of the polyester substrate for the anti-glare film is ≤1500 nm, and this can be achieved by adjusting its average refractive index n. p The first refractive index n1 of the first base coating and the second refractive index n2 of the second base coating make the anti-glare film satisfy the following relationship: n p >n1>n2, and (n p -n1) / (n p With a haze of -n²) ≤ 0.7, interference rainbow patterns can be avoided. Furthermore, even if the total haze of the anti-glare coating on the first base layer side is approximately ≤ 50%, or even preferably ≤ 5%, interference rainbow patterns can still be avoided. It is not necessary to disrupt the light interference through the interfaces on both sides of the polyester substrate using a surface treatment layer with excessive haze or high surface roughness, thus avoiding a reduction in image light transmittance or clarity. It is also not necessary to use a polyester substrate with an extremely high in-plane phase difference value (≥ 8000 nm) as the substrate for the anti-glare film of the display, thus reducing interference rainbow patterns.

[0108] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. An anti-glare film, comprising: a polyester substrate having an average in-plane retardation < 1500 nm and an average refractive index (n p ) between 1.60 and 1.70 an anti-glare coating layer formed on one side of the polyester substrate, wherein the anti-glare coating layer comprises an acrylic binder and a plurality of organic microparticles; and a first base coat layer formed between the polyester substrate and the anti-glare coat layer, wherein the first base coat layer has a first refractive index (n1) between 1.55 and 1.65, and an average refractive index (n p ) of the polyester substrate is greater than the first refractive index (n1) of the first base coat layer.

2. The anti-glare film according to claim 1, wherein the birefringence difference of the polyester substrate is between 0.003 and 0.

015.

3. The anti-glare film according to claim 1, wherein the anti-glare coating layer contains 0.5 to 25 parts by weight of the organic microparticles per 100 parts by weight of the acrylic binder.

4. The anti-glare film according to claim 1, wherein the anti-glare coating layer further contains 0.5 to 12 parts by weight of silica nanoparticles per 100 parts by weight of the acrylic binder.

5. The anti-glare film according to claim 1, wherein the polyester substrate is a uniaxially stretched or biaxially stretched polyester film.

6. The anti-glare film according to claim 1, further comprising an anti-reflective layer formed on the anti-glare coating layer.

7. The anti-glare film according to claim 1, further comprising a second primer layer formed on the other side of the polyester substrate opposite the first primer layer, wherein the second primer layer has a second refractive index (n2) between 1.51 and 1.60, and the average refractive index (n p ) of the polyester substrate, the first refractive index n1 of the first primer layer, and the second refractive index n2 of the second primer layer satisfy the relationship: (n p -n1) / (n p -n2)≤0.7 and (n1-n2)≥0.

05.

8. An anti-glare film, comprising: a polyester substrate having an average in-plane retardation < 1500 nm and an average refractive index (n p ) between 1.60 and 1.70 an anti-glare coating layer formed on one side of the polyester substrate, wherein the anti-glare coating layer comprises an acrylic binder and a plurality of amorphous silica microparticles; and a first base coat layer formed between the polyester substrate and the anti-glare coat layer, wherein the first base coat layer has a first refractive index (n1) between 1.55 and 1.65, and an average refractive index (n p ) of the polyester substrate is greater than the first refractive index (n1) of the first base coat layer.

9. The anti-glare film according to claim 8, wherein the anti-glare coating layer contains 2 to 35 parts by weight of the amorphous silica microparticles per 100 parts by weight of the acrylic binder.

10. The anti-glare film according to claim 8, wherein the anti-glare coating layer further contains 3 to 20 parts by weight of organic microparticles per 100 parts by weight of the acrylic binder.

Images