Multifunctional optical film and preparation method thereof

Abstract

The invention relates to the technical field of optical film materials, in particular to a multifunctional optical film and a preparation method thereof. The preparation method of the multifunctional optical film comprises the following steps: forming a first microstructure containing a metal pointed cone on the surface of a metal substrate by using an electrochemical deposition method; coating transparent resin on the optical film substrate, transferring the first microstructure onto the transparent resin by taking the metal substrate with the first microstructure on the surface as a template, curing and demolding, and forming a transparent resin layer with a second microstructure on the optical film substrate; and preparing an anti-fingerprint resin layer on the surface of the second microstructure of the transparent resin layer to obtain the multifunctional optical film. Compared with a traditional 3A optical film process, the preparation method has the advantage that the high-yield multifunctional optical film can be conveniently and efficiently produced.

Description

Technical Field

[0001] This application belongs to the technical field of optical films, and particularly relates to a multifunctional optical film and a preparation method thereof. Background Art

[0002] An optical film refers to a thin film of an optical dielectric material composed of thin layered dielectrics that propagates light beams through interfaces. Common examples include reflective films, anti-reflective films, polarizing films, brightness enhancement films, beam splitting films, etc. A multifunctional optical film refers to an optical film material that simultaneously exhibits multiple optical effects.

[0003] Multifunctional optical films play an important role in many fields such as building materials, transportation, new displays, and electronic devices. Taking large-size display devices as an example, in a sunlight environment, a screen with high definition, anti-fingerprint, and anti-reflection properties becomes particularly important. In addition, due to their large size, outdoor large screens require good anti-glare and anti-reflection functions to provide good viewing angles and high contrast. Based on this, single-functional optical films on the market are gradually turning into multifunctional 3A optical films that simultaneously possess anti-glare (AG), anti-reflective (AR), and anti-fingerprint (AF) properties.

[0004] However, based on the current structure of 3A optical films, their manufacturing process system is relatively complex. Not only are the processes cumbersome and costly, but the production efficiency is also low. Summary of the Invention

[0005] The purpose of this application is to provide a multifunctional optical film and a preparation method thereof, aiming to solve the problem of how to better realize the preparation of a multifunctional optical film with 3A effects.

[0006] To achieve the above application purpose, the technical solution adopted in this application is as follows:

[0007] In the first aspect, this application provides a preparation method for a multifunctional optical film, including:

[0008] Forming a first microstructure containing metal cones on the surface of a metal substrate by electrochemical deposition;

[0009] Coating a transparent resin on an optical film substrate, using the metal substrate with the first microstructure on its surface as a template, transferring the first microstructure onto the transparent resin and curing and demolding it to form a transparent resin layer with a second microstructure on the optical film substrate;

[0010] Preparing an anti-fingerprint resin layer on the surface of the second microstructure of the transparent resin layer to obtain a multifunctional optical film.

[0011] In a second aspect, the present application provides a multi-functional optical film, comprising: an optical film substrate, a transparent resin layer and an anti-fingerprint resin layer located on the optical film substrate, the transparent resin layer being located between the optical film substrate and the anti-fingerprint resin layer, and the surface of the transparent resin layer close to the anti-fingerprint resin layer having a second microstructure; wherein, the second microstructure is obtained by transfer printing using a metal substrate with a first microstructure provided on its surface, and the first microstructure includes metal cones formed by electrochemical deposition.

[0012] In the method for preparing the multi-functional optical film provided in the first aspect of the present application, when preparing the transparent resin layer in the middle, a metal substrate with a first microstructure on its surface is used as a template for transfer printing to form a second microstructure on the surface of the transparent resin layer. The first microstructure of this template has metal hammers formed by electrochemical deposition. Such a template is not only easy to obtain, but also has a microstructured surface with stable structure and appropriate size. Combining with the transfer printing technology, a transparent resin layer with good anti-glare and anti-reflection effects can be quickly realized. Finally, by preparing an anti-fingerprint resin layer on the surface of the second microstructure of the transparent resin layer, a multi-functional optical film with 3A effects is obtained. Compared with the traditional 3A optical film process, the preparation method of the present application not only has a high yield, but also can conveniently and efficiently produce multi-functional optical films.

[0013] The multi-functional optical film provided in the second aspect of the present application includes an optical film substrate, a transparent resin layer and an anti-fingerprint resin layer stacked in sequence. Based on the fact that the second microstructure on the surface of the transparent resin layer is obtained by transfer printing using a metal substrate with a first microstructure formed by electrochemical deposition of metal cones on its surface, therefore, the multi-functional optical film of the present application not only has good 3A effects, but also is easy to mass-produce efficiently and has a high yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0015] Figure 1 is a schematic flowchart of the method for preparing the multi-functional optical film in the embodiment of the present application;

[0016] Figure 2 is a schematic diagram of a transfer printing method for transferring the first microstructure on the surface of the template to the transparent resin on the surface of the optical film substrate in the method for preparing the multi-functional optical film in the embodiment of the present application;

[0017] Figure 3It is a schematic diagram of another transfer method for transferring the first micro-structure on the surface of the template to the transparent resin on the surface of the optical film substrate in the preparation method of the multi-functional optical film according to the embodiments of the present application;

[0018] Figure 4 It is a schematic diagram of the structure of the multi-functional optical film prepared according to the embodiments of the present application; wherein, A is a schematic diagram of the transparent resin layer with the second micro-structure formed after the transfer is completed, and B is a schematic diagram after the preparation of the anti-fingerprint resin layer is completed;

[0019] Figure 5 It is an SEM image of the first micro-structure of nickel metal cones prepared by electrochemical deposition according to the embodiments of the present application;

[0020] Figure 6 It is to transfer Figure 5 The SEM image of the second micro-structure formed on the surface of the transparent resin layer after the transfer of the first micro-structure in;

[0021] Figure 7 It is an SEM image of the first micro-structure of copper metal cones prepared by electrochemical deposition according to the embodiments of the present application;

[0022] Figure 8 It is to transfer Figure 7 The SEM image of the second micro-structure formed on the surface of the transparent resin layer after the transfer of the first micro-structure in;

[0023] Figure 9 It is the reflectivity curve of the multi-functional optical film prepared according to the embodiments of the present application and the comparative example. Detailed implementation manners

[0024] In order to make the technical problems to be solved, technical solutions and beneficial effects of the present application clearer, the present application will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] In the present application, the term "and / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B may represent: A exists alone, A and B exist simultaneously, and B exists alone. Wherein A and B may be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0026] In the present application, "at least one" means one or more, and "a plurality" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single item (s) or plural item (s).

[0027] It should be understood that in various embodiments of the present application, the magnitudes of the serial numbers of the above processes do not imply the sequence of execution. Some or all of the steps can be executed in parallel or sequentially. The execution sequence of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0028] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms of "a", "the", and "said" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0029] The weights of the relevant components mentioned in the specification of the embodiments of the present application can not only refer to the specific contents of each component, but also represent the proportional relationship of the weights between the components. Therefore, as long as the contents of the relevant components in the specification of the embodiments of the present application are enlarged or reduced in proportion, they are within the scope disclosed in the specification of the embodiments of the present application. Specifically, the mass described in the specification of the embodiments of the present application can be mass units well-known in the chemical industry such as μg, mg, g, kg, etc.

[0030] The terms "first" and "second" are only used for descriptive purposes to distinguish objects such as substances from each other, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX can also be referred to as the second XX. Similarly, the second XX can also be referred to as the first XX. Thus, the features defined with "first" and "second" can explicitly or implicitly include one or more of such features.

[0031] In the current 3A film manufacturing process system, a relatively common solution is to first coat a layer of nano-silica particle resin layer on the substrate to scatter incident light to achieve an AG effect; then, on the surface of this film, use magnetron sputtering coating technology to stack and coat a designed multi-layer of silicon nitride and silicon dioxide layers, so that the reflected light cancels each other out in opposite phases between the upper and lower layers to achieve an AR effect; finally, use vacuum coating technology to coat an extremely thin AF layer on the film surface to finally form a 3A film. This manufacturing process takes a long time, not only spanning steps such as coating, cleaning, curing and baking, and transfer, with a cumbersome process, but also the manufacturing equipment used is expensive. The yield problem caused by the long process makes the product price high.

[0032] Based on this, when the present application prepares a transparent resin layer in the middle with good anti-glare and anti-reflection effects, the first microstructure of the metal hammer deposited electrochemically is transferred onto the surface of the transparent resin layer by a transfer method to form a second microstructure, so that a multi-functional optical film with high yield can be produced conveniently and efficiently. The specific technical solutions are as follows.

[0033] In a first aspect, an embodiment of the present application provides a method for preparing a multifunctional optical film. Specifically, as Figure 1 described, the preparation method of the embodiment of the present application includes:

[0034] S01: Forming a first microstructure containing metal cones on the surface of a metal substrate by means of electrochemical deposition;

[0035] S02: Coating a transparent resin on an optical film substrate, using the metal substrate with the first microstructure on its surface as a template, transferring the first microstructure onto the transparent resin and curing and demolding it, so as to form a transparent resin layer with a second microstructure on the optical film substrate;

[0036] S03: Preparing an anti-fingerprint resin layer on the surface of the second microstructure of the transparent resin layer to obtain a multifunctional optical film.

[0037] When preparing the transparent resin layer in the embodiment of the present application, a unique template is used for transfer printing, that is, the metal substrate with the first microstructure on its surface is used as a template for transfer printing to form a second microstructure on the surface of the transparent resin layer. After the first microstructure is transferred and demolded on the surface of the transparent resin layer, the second microstructure is formed. That is, the first microstructure and the second microstructure can be complementary and interlocked in space.

[0038] In the embodiment of the present application, the first microstructure of the template has electrochemically deposited metal hammers. Such a template is not only easy to obtain, but also has a microstructural surface with stable structure and appropriate size. Combining with the transfer printing technology, a transparent resin layer with good anti-glare and anti-reflection effects can be quickly realized. Finally, by preparing an anti-fingerprint resin layer on the surface of the second microstructure of the transparent resin layer, a multifunctional optical film with 3A effect is obtained. The entire preparation process of the embodiment of the present application not only has high production efficiency, but also has high yield, so it can be better mass-produced and the popularization of the multifunctional optical film can be expanded.

[0039] Step S01 is the preparation process of the transfer printing template, and the transfer printing template is the metal substrate with the first microstructure on its surface.

[0040] In some embodiments, the step of forming a first microstructure containing metal cones on the surface of a metal substrate by means of electrochemical deposition includes: preparing a mixture mother liquor containing metal salt, boric acid and ammonium salt; using the metal substrate as the cathode, placing it in the mixture mother liquor together with the anode metal material, and then passing an electric current for electrochemical deposition. That is, the embodiment of the present application can use the cathode electrochemical deposition method to grow metal cones directionally on the metal substrate at the cathode to form the first microstructure. Specifically, the first microstructure can be a metal cone array structure.

[0041] In some embodiments, during the electrochemical deposition process, the pH value of the prepared mixture mother liquor is 3 to 5. Electrochemical reactions at this pH value are conducive to the deposition of metal cones. In some embodiments, during the electrochemical deposition process, the temperature of the prepared mixture mother liquor is 40 to 80 °C; at this temperature, the rate of the electrochemical reaction can be increased, which is conducive to deposition.

[0042] In some embodiments, during the electrochemical deposition process, the metal salt concentration in the prepared mixture mother liquor is 0.8 to 2.0 mol / L; the spacing of the metal cones deposited within this concentration range is appropriate. In some embodiments, during the electrochemical deposition process, the molar ratio of metal salt, boric acid, and ammonium salt in the prepared mixture mother liquor is 1:(0.2 to 2.0):(0.5 to 5.0); the rate of the electrochemical deposition reaction is appropriate at this molar ratio.

[0043] In some embodiments, during the electrochemical deposition process, the distance between the metal substrate of the cathode and the anode metal material is 0.1 to 20 cm; there is a good impedance range at this distance, which is conducive to the occurrence of the electrochemical deposition reaction.

[0044] In some embodiments, during the electrochemical deposition process, the current density of the applied current is 0.1 to 5 A / dm 2 ². At this current density, it is conducive to the occurrence of the electrochemical deposition reaction.

[0045] Exemplarily, the steps of forming a first microstructure containing metal cones on the surface of a metal substrate by electrochemical deposition method include: (1) preparing a mixture mother liquor containing metal salt, boric acid, and ammonium salt. Specifically, the metal salt solution and additives (i.e., boric acid and ammonium salt) are fully mixed and ultrasonically treated, and the temperature is adjusted to 40 to 80 °C and pH = 3 to 5 to obtain the mixture mother liquor; among them, the ammonium salt includes at least one of soluble ammonium hypophosphite, ammonium chloride, or ethylenediamine dihydrochloride, etc., and the molar ratio of metal salt, boric acid (H₃BO₃), and ammonium salt is 1:0.2 to 2.0:0.5 to 5.0. Among them, the metal salt includes at least one of nickel salt and copper salt, and the soluble nickel salt can be one or several of nickel chloride, nickel nitrate, nickel sulfate, nickel oxalate, nickel acetate, etc., and the soluble copper salt can be one or several of copper chloride, copper nitrate, copper sulfate, copper oxalate, copper acetate, etc. (2) inserting the cathode metal substrate and the anode metal material into the mixture mother liquor, the distance between the anode metal material and the cathode metal substrate can be 0.1 to 20 cm, and a current with a current density of 0.1 to 5 A / dm 2 ² is applied between the anode metal material and the cathode metal substrate for electrochemical deposition, and the current deposition time can be 5 to 20 min. Finally, the deposited cathode metal substrate can be taken out, rinsed with deionized water, and dried to obtain a template with a first microstructure having metal cones on the surface.

[0046] In the above process, the material of the metal substrate of the cathode includes at least one of nickel and copper. For example, a polished copper sheet can be used, specifically, a polished copper sheet polished by a chemical solution through chemical mechanical polishing. The anode metal material can be at least one of nickel and copper, and generally, it is selected according to the metal salt in the mother liquor of the mixture to generate corresponding metal cones on the surface of the cathode metal substrate. For example, if the metal salt is a nickel salt, the anode metal material is nickel, and nickel metal cones are formed on the surface of the cathode metal substrate after electrochemical deposition. If the metal salt is a copper salt, the anode metal material is copper, and copper metal cones are formed on the surface of the cathode metal substrate after electrochemical deposition.

[0047] Through the above electrochemical deposition process, the metal cones in the first microstructure can have a certain size. For example, the width of the metal cone is 0.1 - 3 μm, and further can be 0.5 - 2 μm; the height of the metal cone is 2 - 10 μm, and further can be 3 - 6 μm; the spacing between adjacent metal cones is 0 - 3 μm, and further can be 0.5 - 2 μm. The first microstructure with metal cones of the above dimensions is stable. After transfer printing, the size space of the second microstructure formed on the surface of the transparent resin layer can be fitted with the first microstructure.

[0048] It should be noted that: in the embodiments of the present application, the width of the metal cone refers to the widest size at the bottom of the cross-section of the metal cone, the height of the metal cone refers to the length from the bottom to the tip of the metal cone, and the spacing between adjacent metal cones is the spacing between the bottoms of the metal cones. Generally, it can be detected by a scanning electron microscope instrument.

[0049] Step S02 is a template transfer process, and this process can transfer the first microstructure on the surface of the template to form a matching second microstructure on the surface of the transparent resin layer.

[0050] Specifically, a transparent resin is first coated on an optical film substrate. Among them, the optical film substrate is a transparent optical film substrate with a thickness of 50-300 μm; the visible light transmittance of the optical film substrate is 90-98%; the haze is 0.1-1%; the optical film substrate includes but is not limited to one or more of polyethylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetal, polyacrylate, polyimide, polyamide, polyethylene terephthalate, polycarbonate, acrylonitrile-butadiene-styrene copolymer, triacetate cellulose, polyethersulfone, and polysulfone. The coating methods include but are not limited to one or more of slot coating, wire bar coating, gravure roll coating, spin coating, knife coating, and screen printing. The coated resin is a transparent resin, including but not limited to one or more of polyurethane, polyacrylate, silane-modified polyacrylate, fluorine-modified acrylate, polymethacrylate, polyacrylated polyacrylonitrile, polyvinyl alcohol, polyamide, polyimide, and polyetherimide; for example, the photocurable transparent resin used can be a 4-5 functional urethane acrylate, which forms a crosslinked high-density structure through polyfunctionality to improve the scratch resistance of the optical film. The functional groups can be allyl, vinyl, cinnamyl, fluorine-substituted, silane-substituted, etc. The number of functional groups, if not particularly limited, can be 2-20 or 4-5.

[0051] Exemplarily, after a transparent resin is first coated on an optical film substrate, there are two transfer methods in the embodiments of the present application.

[0052] Among them, the step of transferring the first microstructure to the transparent resin and curing it and then demolding includes: pressing the first microstructure on the surface of the metal substrate against the transparent resin on the surface of the optical film substrate, and then separating and demolding the metal substrate from the optical film substrate after curing. That is, it can be understood as a direct surface-to-surface fitting method between the template and the transparent resin.

[0053] As Figure 2 shown, it is a schematic structural diagram of direct surface-to-surface fitting and pressing. Specifically, the transparent resin surface of the transparent optical film substrate is covered on the first microstructure of the metal cone of the template; two pieces of transparent hard materials (such as transparent tempered glass) are used to clamp and fasten the fixture, and pressure is applied; then the transparent resin in the combination is cured, and finally the transparent resin is separated and demolded.

[0054] The transparent rigid material includes, but is not limited to, one or more of tempered glass, polymethyl methacrylate, polycarbonate, polystyrene, styrene-acrylonitrile copolymer, transparent nylon, polyethersulfone, and polyethylene terephthalate. The applied pressure can be 0.1 - 5 MPa, such as 0.5 - 2 MPa. The curing method in this process can be one or more of thermal curing, moisture curing, or ultraviolet curing. Among them, the temperature for thermal curing can be 50 - 200 °C, such as 80 - 150 °C, and the thermal curing time can be 10 - 90 min, such as 50 - 80 min. The humidity for moisture curing can be 40 - 100%, such as 60 - 100%, and the moisture curing time can be 4 - 24 h, such as 12 - 24 h. The wavelength for ultraviolet curing can be 210 - 420 nm, such as 320 - 400 nm, and the cumulative energy for ultraviolet curing can be 100 - 600 mJ, such as 200 - 400 mJ.

[0055] Among them, another step of transferring the first microstructure onto the transparent resin, curing it, and then demolding includes: wrapping the metal substrate around the pressing roller, and then pressing the surface of the metal substrate with the first microstructure onto the transparent resin on the surface of the optical film substrate, and completing the curing and demolding while rolling. That is, it can be understood that the template is attached to the transparent resin in a rolling manner.

[0056] As Figure 3 shown, it is a schematic structural diagram of rolling attachment. Specifically, the template with the first microstructure is completely wrapped around the pressing roller (which can be a metal pressing roller, for example), and the first microstructure faces outward; then the pressing roller is pressed onto the transparent resin on the surface of the optical film substrate. At this time, the part where the pressing roller contacts the transparent resin can be cured, and the pressing roller cures while rolling forward, that is, curing and final demolding are completed during the rolling process. Among them, the pressing roller can be a metal pressing roller, and its diameter can be 3 - 30 cm, such as 6 - 12 cm. The methods for wrapping the template around the pressing roller include, but are not limited to, one or more of fitting and welding. The pressure of the pressing roller is 0.05 - 5 MPa, such as 0.1 - 1 MPa. The curing method in this process can be one or more of thermal curing, moisture curing, or ultraviolet curing. Among them, the temperature for thermal curing can be 50 - 200 °C, such as 80 - 150 °C, and the thermal curing time can be 10 - 90 min, such as 50 - 80 min. The humidity for moisture curing can be 40 - 100%, such as 60 - 100%, and the moisture curing time can be 4 - 24 h, such as 12 - 24 h. The wavelength for ultraviolet curing can be 210 - 420 nm, such as 320 - 400 nm, and the cumulative energy for ultraviolet curing can be 100 - 600 mJ, such as 200 - 400 mJ.

[0057] In some embodiments, the steps of preparing the anti-fingerprint resin layer on the second microstructure surface of the transparent resin layer include: formulating an anti-fingerprint transparent resin solution containing resin, cross-linking agent and solvent, coating the anti-fingerprint transparent resin solution on the second microstructure surface, and obtaining the anti-fingerprint resin layer after curing. As Figure 4 shown, A is the schematic diagram of the transferred structure, while B is the complete multi-functional optical film finally formed with the anti-fingerprint resin layer.

[0058] In some embodiments, the above-prepared anti-fingerprint transparent resin solution includes resin, cross-linking agent and solvent; the resin includes but is not limited to one or several of polyurethane, polyacrylate, silane-modified polyacrylate, fluorine-modified acrylate, polymethacrylate, polyacrylonitrile polyacrylate, polyvinyl alcohol, polyamide, polyimide, polyetherimide; the cross-linking agent, namely photoinitiator, can include but is not limited to one or several of triaryl sulfonium salts, benzoin, benzil, α-hydroxy ketone, α-amino ketone, acetophenone, benzoyl formate, acylphosphine, alkyl peroxide, peroxide ester, azobisisobutyronitrile, azobisisoheptonitrile, benzoyl peroxide.

[0059] In some embodiments, in the above-prepared anti-fingerprint transparent resin solution, the resin content is 0.1-10 wt%; the thickness of the liquid film formed by coating the anti-fingerprint transparent resin solution on the second microstructure surface can be 1-10 μm; after curing, the thickness of the dry film, i.e., the final anti-fingerprint resin layer, can be 0.01-1 μm. The coating methods in this process include but are not limited to one or several of slot coating, wire bar coating, gravure coating, spin coating, knife coating and screen printing. The curing method is the same as that of the above intermediate layer, i.e., the transparent resin layer with the second microstructure, and can be one or more of heat curing, moisture curing or ultraviolet curing.

[0060] In a second aspect, an embodiment of the present application provides a multi-functional optical film. Specifically referring to Figure 4 B shown in, it includes: an optical film substrate, a transparent resin layer and an anti-fingerprint resin layer. The transparent resin layer is located between the optical film substrate and the anti-fingerprint resin layer, and the surface of the transparent resin layer close to the anti-fingerprint resin layer has a second microstructure; wherein, the second microstructure is obtained by transfer printing using a metal substrate with a first microstructure on the surface, and the first microstructure includes metal cones formed by electrochemical deposition.

[0061] In the multi-functional optical film of the embodiment of the present application, based on the fact that the second microstructure on the surface of the transparent resin layer is obtained by transfer printing using a metal substrate with a first microstructure of metal cones formed by electrochemical deposition on the surface, therefore, this multi-functional optical film not only has good 3A effect, but also is easy to be mass-produced efficiently on a large scale with high yield.

[0062] Specifically, the multifunctional optical film of the embodiments of the present application is prepared by the above preparation method of the embodiments of the present application. Among them, for the formation process of the first microstructures on the surface of the metal substrate and related materials and parameters, refer to the above.

[0063] In some embodiments, the thickness of the optical film substrate at the bottom of the multifunctional optical film can be 50 - 300 μm; the visible light transmittance can be 90% - 98%; the haze can be 0.1% - 1%; the material can be selected from at least one of polyethylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetal, polyacrylate, polyimide, polyamide, polyethylene terephthalate, polycarbonate, acrylonitrile-butadiene-styrene copolymer, cellulose triacetate, polyethersulfone, and polysulfone.

[0064] In some embodiments, the thickness of the transparent resin layer in the middle of the multifunctional optical film is 2 - 200 μm, and this thickness can be understood as the thickness from the surface of the transparent resin layer adjacent to the substrate to the surface of the second microstructures; the resin of the transparent resin layer is selected from at least one of polyurethane, polyacrylate, silane-modified polyacrylate, fluorine-modified acrylate, polymethacrylate, polyacrylated polyacrylonitrile, polyvinyl alcohol, polyamide, polyimide, and polyetherimide. And the spatial dimensions of the second microstructures on the surface of the transparent resin layer can be fitted with the first microstructures of the template.

[0065] In some embodiments, the thickness of the anti-fingerprint resin layer on the surface of the multifunctional optical film can be 0.01 - 1 μm; the resin can be selected from at least one of polyurethane, polyacrylate, silane-modified polyacrylate, fluorine-modified acrylate, polymethacrylate, polyacrylated polyacrylonitrile, polyvinyl alcohol, polyamide, polyimide, and polyetherimide; the anti-fingerprint resin layer contains a crosslinking agent, and the crosslinking agent is selected from one of triarylsulfonium salts, benzoin, benzil, α-hydroxy ketones, α-amino ketones, acetophenone, benzoyl formate, acylphosphines, alkyl peroxides, peresters, azobisisobutyronitrile, azobisisoheptonitrile, and benzoyl peroxide.

[0066] The following will be described in conjunction with specific embodiments. Materials, reagents, etc. used in the following embodiments can be obtained from commercial sources without special instructions. For those not specified in the following embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be purchased commercially.

[0067] Example 1

[0068] A multifunctional optical film includes: an optical film substrate, a transparent resin layer, and an anti-fingerprint resin layer. The transparent resin layer is located between the optical film substrate and the anti-fingerprint resin layer, and the surface of the transparent resin layer close to the anti-fingerprint resin layer has second microstructures. The preparation method of this multifunctional optical film includes the following steps:

[0069] (1) Select a polished copper sheet with a thickness of 100 μm and a size of 10*10 cm as the cathode, and nickel foam as the anode. Prepare a mother liquor of a mixture of 0.8 mol / L nickel chloride hexahydrate, 3.5 mol / L ammonium chloride, and 0.5 mol / L boric acid as the electrolyte, and adjust the pH value to between 3 and 5. Insert the above cathode and anode into the electrolyte, keep the distance between the cathode and the anode at 3 cm, and deposit at a current density of 0.1 A / dm 2 for 10 min at 80 °C to obtain a first microstructure composed of nickel metal cones on the surface of the polished copper sheet of the cathode. The microstructure is as shown in Figure 5 .

[0070] (2) Select a PET transparent material with a thickness of 125 μm and a size of 26*34 cm as the optical film substrate. Using the slot coating process, coat a layer of photocurable transparent resin with a thickness of 30 μm (Z-975-H03C photocurable acrylic resin, Taier Adhesives (Guangdong) Co., Ltd.), the coating rate is 8 m / s, and the liquid outlet rate is 0.02 ml / s.

[0071] Refer to Figure 2 . After coating the photocurable transparent resin on the surface of the optical film substrate, the surface of the polished copper sheet with the first microstructure of nickel metal cones obtained in the above steps is covered on the transparent resin on the surface of the optical film substrate, clamped with transparent tempered glass from above and below, and fastened with a clamp (the fastening pressure is 0.5 MPa). Subsequently, the transparent resin is cured by ultraviolet light irradiation (using a mercury lamp as the light source, and the cumulative curing energy is 200 mJ). Finally, the transparent resin layer with the second microstructure is peeled off. The microstructure is as shown in Figure 6 .

[0072] (3) Using the slot coating process, coat a layer of anti-fingerprint transparent resin solution with a thickness of 10 μm on the surface of the above second microstructure, the coating rate is 8 m / s, and the liquid outlet rate is 0.02 ml / s; among them, the anti-fingerprint transparent resin solution includes resin (accounting for 30% of the total weight, 1240 fluorocarbon-modified photocurable acrylic resin, Dongguan Siyezi Plastic Co., Ltd.), cross-linking agent (accounting for 2% of the total weight, 6992 photoinitiator triarylsulfonium salt, Hubei Shineng Chemical Technology Co., Ltd.) and solvent (PGME, propylene glycol methyl ether). Then it is sent to an oven for drying (the drying temperature is 100 °C and the time is 1 min), and then cured by ultraviolet light irradiation (using a mercury lamp as the light source, and the cumulative curing energy is 200 mJ) to form an anti-fingerprint resin layer with a thickness of 1 μm. The optical film substrate, the transparent resin layer with the second microstructure, and the anti-fingerprint resin layer form the final multifunctional optical film product.

[0073] Example Two

[0074] A multifunctional optical film, comprising: an optical film substrate, a transparent resin layer, and an anti-fingerprint resin layer, wherein the transparent resin layer is located between the optical film substrate and the anti-fingerprint resin layer, and the surface of the transparent resin layer close to the anti-fingerprint resin layer has a second microstructure. The preparation method of the multifunctional optical film comprises the following steps:

[0075] (1) Select a polished copper sheet with a thickness of 100 μm and a size of 10*10 cm as the cathode, and another polished copper sheet as the anode. Prepare a mixed mother liquor of 0.85 mol / L ammonium hypophosphite, 0.5 mol / L boric acid, and 0.3 mol / L copper sulfate as the electrolyte, and adjust the pH value to between 3 and 5. Insert the above cathode and anode into the electrolyte, keep the distance between the cathode and the anode at 3 cm, and deposit at a current density of 0.12 A / dm 2 for 10 min at 80 °C to obtain a first microstructure composed of copper metal cones on the surface of the polished copper sheet of the cathode. The microstructure is as shown in Figure 7 .

[0076] (2) Select a PET transparent material with a thickness of 125 μm and a size of 26*34 cm as the optical film substrate, and use the slot coating process to coat a layer of photocurable transparent resin (Z-975-H03C photocurable acrylic resin) with a thickness of 30 μm. The coating rate is 8 m / s, and the liquid outlet rate is 0.02 ml / s.

[0077] Refer to Figure 3 . After coating the photocurable transparent resin on the surface of the optical film substrate, bond the polished copper sheet with the first microstructure of copper metal cones obtained in the above step to the metal pressing roller with the first microstructure facing outwards. While irradiating with ultraviolet light, the metal pressing roller rolls forward. At this time, the ultraviolet light (using a mercury lamp as the light source, and the cumulative curing energy is 200 mJ) should always irradiate the contact area between the metal pressing roller and the transparent resin on the surface of the optical film substrate (the pressure of the metal pressing roller is 0.1 Mpa) and move forward together with the metal pressing roller. In this process, the curing and demolding of the transparent resin will be completed simultaneously, and finally a transparent resin layer with a second microstructure is obtained. The microstructure is as shown in Figure 8 .

[0078] (3) Using the slot coating process, a layer of anti-fingerprint transparent resin solution with a thickness of 10 μm is coated on the surface of the above-mentioned second microstructure. The coating rate is 8 m / s, and the liquid outlet rate is 0.02 ml / s. Among them, the anti-fingerprint transparent resin solution includes resin (accounting for 30% of the total weight, 1240 fluorocarbon-modified photocurable acrylic resin), cross-linking agent (accounting for 2% of the total weight, 6992 photoinitiator triarylsulfonium salt), and solvent (PGME, propylene glycol methyl ether). Then it is sent to an oven for drying (drying temperature is 100 °C, time is 1 min), and then cured by ultraviolet light irradiation (using a mercury lamp as the light source, the cumulative curing energy is 200 mJ) to form an anti-fingerprint resin layer with a thickness of 1 μm. The optical film substrate, the transparent resin layer with the second microstructure, and the anti-fingerprint resin layer form the final multi-functional optical film product.

[0079] Control group

[0080] A multi-functional optical film includes: an optical film substrate, an AG resin layer, an AR layer, and an anti-fingerprint resin layer, which are arranged in sequence from the optical film substrate upwards. The preparation method of this multi-functional optical film includes the following steps:

[0081] (1) Select a PET transparent material with a thickness of 125 μm and a size of 26 * 34 cm as the optical film substrate. Using the slot coating process, a layer of AG resin with a thickness of 30 μm is coated. The coating raw material is composed of 10% of Z-975-H03C photocurable acrylic resin, 3% of silica particles, and the remaining weight of propylene glycol methyl ether solvent. The coating rate is 8 m / s, and the liquid outlet rate is 0.02 ml / s.

[0082] Then it is sent to an oven for drying (drying temperature is 100 °C, time is 1 min), and then cured by ultraviolet light irradiation of a mercury lamp with a cumulative energy of 200 mJ to form an AG resin layer with a thickness of 3 μm.

[0083] (2) Using magnetron sputtering technology, an 80-nm TiO2 layer, a 120-nm SiO2 layer, and a 100-nm MgF2 layer are sequentially deposited on the surface of the AG resin layer. The magnetron sputtering parameters are: vacuum degree 5 × 10-3 Pa, target power density 3 W / cm 2 , substrate temperature 100 °C, and finally an AR layer is formed.

[0084] (3) Using the slot coating process, a layer of anti-fingerprint transparent resin solution with a thickness of 10 μm is coated on the surface of the AR layer. The coating rate is 8 m / s, and the liquid discharge rate is 0.02 ml / s. Among them, the anti-fingerprint transparent resin solution includes 30% of 1240 fluorocarbon-modified photocurable acrylic resin, 2% of 6992 photoinitiator triarylsulfonium salt, and the remaining weight of propylene glycol methyl ether solvent. Then it is sent to an oven for drying (the drying temperature is 100 °C and the time is 1 min), and then cured by mercury lamp irradiation with a cumulative energy of 200 mJ to form an anti-fingerprint resin layer with a thickness of 1 μm, obtaining the final multi-functional optical film product.

[0085] Performance detection

[0086] The multi-functional optical films obtained according to Example 1, Example 2, and the control group are subjected to optical film performance tests. Figure 9 is the reflectivity curve in the visible light band (360 - 780 nm). Compared with the optical film of the control group, in the intervals of 360 - 410 nm and 720 - 780 nm, the reflectivity of Example 1 is lower than that of the control group, and there is also a low band with a reflectivity lower than that of the control group in Example 2, indicating that the anti-reflection effect of the products in Example 1 and Example 2 is better in these bands.

[0087] Use a spectrophotometer to measure the haze and total reflectance of the multi-functional optical film, and use a surface water contact angle measuring instrument to measure the water droplet angle of the multi-functional optical film. The results are shown in Table 1.

[0088] Table 1

[0089] Example 1 Example 2 Control group Haze 52.37％ 76.07％ 41.72％ Water contact angle 110° 108° 104° Integrated reflectance 2.80％ 5.24％ 2.43％

[0090] It can be seen from the data in Table 1 that the haze and water droplet angles of the multi-functional optical films in Example 1 and Example 2 are better than those of the control group, and the performance in anti-glare and anti-fingerprint is better. In terms of the total reflectance, although the total reflectance of the multi-functional optical film in the examples is slightly lower than that of the control group, compared with the products without the AR layer (the total reflectance generally exceeds 8%), the examples of the present application can also achieve a good anti-reflection effect. Moreover, more importantly, the production efficiency and product yield of the multi-functional optical films in the examples of the present application are higher than those of the comparative examples.

[0091] The above are only the preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a multifunctional optical film, characterized in that: include: forming a first microstructure containing metal cones on the surface of the metal substrate by electrochemical deposition; Coating a transparent resin on the optical film substrate, using the metal substrate having the first microstructure on the surface as a template, transferring the first microstructure onto the transparent resin, curing and demolding, and forming a transparent resin layer having a second microstructure on the optical film substrate; An anti-fingerprint resin layer is prepared on the second microstructure surface of the transparent resin layer to obtain a multifunctional optical film.

2. The preparation method according to claim 1, characterized in that The step of forming a first microstructure containing metal cones on the surface of a metal substrate by electrochemical deposition comprises: preparing a mixed mother solution containing metal salt, boric acid and ammonium salt; using the metal substrate as a cathode and placing an anode metal material in the mixed mother solution, and then passing an electric current for electrochemical deposition.

3. The preparation method according to claim 2, characterized in that: The mother mixture satisfies at least one of the following (1)-(6): (1) The pH value of the mixture mother liquor is 3 to 5; (2) The temperature of the mixture mother liquor is 40 to 80° C.; (3) The concentration of the metal salt in the mixture mother liquor is 0.8 to 2.0 mol / L; (4) The molar ratio of the metal salt, the boric acid and the ammonium salt in the mother liquor of the mixture is 1:(0.2-2.0):(0.5-5.0); (5) the metal salt in the mixed mother liquor includes at least one of a nickel salt and a copper salt; (6) The ammonium salt in the mixed mother liquor includes at least one of ammonium hypophosphite, ammonium chloride and ethylenediamine hydrochloride.

4. The preparation method according to claim 2, characterized in that: The material of the metal substrate includes at least one of nickel and copper; And / or, the distance between the metal substrate and the anode metal material is 0.1 to 20 cm; And / or, the current density of the current is 0.1-5A / dm 2 of current.

5. The preparation method according to claim 1, characterized in that: The step of transferring the first microstructure to the transparent resin and demolding after curing comprises: laminating the first microstructure on the surface of the metal substrate and the transparent resin on the surface of the optical film substrate, applying pressure, and then separating the metal substrate from the optical film substrate and demolding after curing; Alternatively, the metal substrate is wrapped on a laminating roller, and then the surface of the metal substrate containing the first microstructure is pressed onto the transparent resin on the surface of the optical film substrate, and the curing and demoulding are completed by rolling while curing.

6. The preparation method according to any one of claims 1 to 5, characterized in that: The width of the metal cone in the first microstructure is 0.1-3 μm, the height is 2-10 μm, and the interval between adjacent metal cones is 0-3 μm.

7. The preparation method according to any one of claims 1 to 5, characterized in that: The step of preparing an anti-fingerprint resin layer on the second microstructure surface of the transparent resin layer comprises: preparing an anti-fingerprint transparent resin solution containing resin, a crosslinking agent and a solvent, coating the anti-fingerprint transparent resin solution on the second microstructure surface, and obtaining the anti-fingerprint resin layer after curing.

8. A multifunctional optical film, characterized in that: include: An optical film substrate and a transparent resin layer and an anti-fingerprint resin layer located on the optical film substrate, wherein the transparent resin layer is located between the optical film substrate and the anti-fingerprint resin layer, and the surface of the transparent resin layer close to the anti-fingerprint resin layer has a second microstructure; wherein the second microstructure is obtained by transfer using a metal substrate with a first microstructure arranged on its surface as a template, and the first microstructure includes a metal cone formed by electrochemical deposition.

9. The multifunctional optical film according to claim 8, characterized in that: The metal cone in the first microstructure has a width of 0.1 to 3 μm, a height of 2 to 10 μm, and a spacing of 0 to 3 μm between adjacent metal cones; And / or, the thickness of the transparent resin layer is 2 to 200 μm; And / or, the resin of the transparent resin layer is selected from at least one of polyurethane, polyacrylate, silane-modified polyacrylate, fluorine-modified acrylate, polymethacrylate, polyacrylic acid compound of polyacrylonitrile, polyvinyl alcohol, polyamide, polyimide and polyetherimide.

10. The multifunctional optical film according to claim 8 or 9, characterized in that: The optical film substrate satisfies at least one of the following items (1) to (4): (1) The thickness of the optical film substrate is 50 to 300 μm; (2) The visible light transmittance of the optical film substrate is 90% to 98%; (3) The haze of the optical film substrate is 0.1 to 1%; (4) The material of the optical film substrate is selected from at least one of polyethylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetal, polyacrylate, polyimide, polyamide, polyethylene terephthalate, polycarbonate, acrylonitrile-butadiene-styrene copolymer, triacetyl cellulose, polyether sulfone, and polysulfone; Alternatively, the anti-fingerprint resin layer satisfies at least one of the following items (a)-(c): (a) the thickness of the anti-fingerprint resin layer is 0.01 to 1 μm; (b) the resin in the anti-fingerprint resin layer is selected from at least one of polyurethane, polyacrylate, silane-modified polyacrylate, fluorine-modified acrylate, polymethacrylate, polyacrylic acid compound of polyacrylonitrile, polyvinyl alcohol, polyamide, polyimide and polyetherimide; (c) The anti-fingerprint resin layer contains a crosslinking agent, and the crosslinking agent is selected from one of triarylsulfonium salts, benzoin, benzil, α-hydroxyketone, α-aminoketone, acetophenone, benzoylformate, acylphosphine, alkyl peroxide, peroxyester, azobisisobutyronitrile, azobisisoheptylonitrile, and benzoyl peroxide.

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