Coating liquid for preparing uv blocking film, method for preparing the same, uv blocking film, optical film assembly, and method for preparing the same

Abstract

The application provides a coating liquid for preparing a UV blocking film, a preparation method of the coating liquid, the UV blocking film, an optical film assembly and a preparation method of the optical film assembly, and belongs to the technical field of optical films. The coating liquid for preparing the UV blocking film comprises a UV absorbing base, an acrylic resin and a solvent; wherein the UV absorbing base comprises a UV absorber and a sol, at least part of the UV absorber is completely wrapped by the sol; and the solvent comprises an ether alcohol solvent. The sol in the coating liquid has a wrapping effect on the UV absorber, and cooperates with the ether alcohol solvent in the coating liquid to inhibit the UV absorber wrapped by the sol from floating to the upper region of the coating liquid. In addition, the sol acts as a filler in the coating liquid, and can also improve the crosslinking density of the acrylic resin during the solidification process of the coating liquid, so that the UV blocking film formed by solidification is relatively dense. The dense UV blocking film can inhibit the UV absorber from precipitating on the surface of the UV blocking film, which is beneficial to avoiding the precipitation problem of the UV blocking film in the later use process.

Description

Technical Field

[0001] The present application relates to the technical field of optical films, and in particular to a coating liquid for preparing a UV barrier film and a preparation method thereof, a UV barrier film, an optical film assembly and a preparation method thereof. Background Art

[0002] As devices containing liquid crystal molecules, such as liquid crystal displays, are increasingly used outdoors, prolonged exposure to ultraviolet light can break the chemical bonds of the liquid crystal molecules within the device, thereby reducing the device's effectiveness.

[0003] To prevent or mitigate the breakage of chemical bonds within the liquid crystal molecules within the device, a UV-blocking film can be applied to the device surface. UV-blocking films primarily utilize various UV absorbers to achieve this UV-blocking function. The UV-blocking film is typically prepared by curing a coating containing a UV absorber and acrylic resin under ultraviolet light in the presence of a photoinitiator to form the UV-blocking film.

[0004] However, after the coating liquid containing UV absorber and acrylic resin is cured to form a UV blocking film, the UV absorber is easily precipitated during subsequent use, resulting in a decrease in the ultraviolet blocking function of the UV blocking film or even failure. Summary of the Invention

[0005] The purpose of the present application is to provide a coating liquid for preparing a UV barrier film and a preparation method thereof, a UV barrier film, an optical film assembly and a preparation method thereof, which aims to improve the technical problem that the UV absorber of the existing UV barrier film is easily precipitated during the later use.

[0006] In a first aspect, the present application provides a coating liquid for preparing a UV barrier film, which includes a UV absorbing matrix, an acrylic resin and a solvent; wherein the UV absorbing matrix includes a UV absorber and a sol, and at least a portion of the UV absorber is completely wrapped by the sol; the solvent includes an ether alcohol solvent.

[0007] In the coating liquid for preparing a UV barrier film provided by the present application, at least part of the UV absorber is completely wrapped by the sol; during the process of curing the coating liquid to form a UV barrier film, the sol has a wrapping effect on the UV absorber, and combined with the ether alcohol solvent in the coating liquid, it can inhibit the UV absorber wrapped by the sol from floating in the upper area of ​​the coating liquid; in addition, the sol serves as a filler in the coating liquid, and during the curing process of the coating liquid, it can also increase the cross-linking density of the acrylic resin, so that the UV barrier film formed by the curing is relatively dense. The dense UV barrier film can inhibit the UV absorber from precipitating on the surface of the UV barrier film, which is beneficial to avoid the precipitation problem of the UV barrier film during later use.

[0008] In combination with the first aspect, in an optional embodiment of the present application, the coating liquid for preparing the UV blocking film includes the following components in parts by weight: 1-10 parts of a UV absorbing matrix, 5-20 parts of an acrylic resin, and 10-100 parts of a solvent; wherein, in the UV absorbing matrix, the mass ratio of the UV absorber to the sol is 1:(1-20).

[0009] In the above technical solution, the present application can effectively inhibit the UV absorber from floating on the surface of the UV barrier film during the process of curing the coating liquid to form the UV barrier film by regulating the ratio between the components in the coating liquid for preparing the UV barrier film. The UV barrier film prepared using the coating liquid for preparing the UV barrier film can have better ultraviolet blocking function, and effectively avoid the precipitation problem during subsequent use.

[0010] Optionally, the solvent further includes a non-ether alcohol solvent, and the mass ratio of the ether alcohol solvent to the non-ether alcohol solvent is ≥2:1.

[0011] Optionally, the coating solution for preparing the UV blocking film further comprises 0.3-2 parts of a photoinitiator.

[0012] Optionally, the coating solution for preparing the UV blocking film further comprises 0.01-0.06 parts of a leveling agent.

[0013] Optionally, the coating solution for preparing the UV blocking film further comprises 1-5 parts of an acrylate monomer.

[0014] Optionally, the non-ether alcohol solvent includes at least one of ethyl acetate, butyl acetate, toluene, xylene, acetone, butanone, cyclohexanone, methyl isobutyl ketone, isopropyl alcohol and isobutyl alcohol.

[0015] In combination with the first aspect, in an optional embodiment of the present application, the sol includes at least one of silica sol, aluminum sol and zirconium sol; or / and, the ether alcohol solvent includes at least one of propylene glycol methyl ether, propylene glycol ethyl ether, ethylene glycol butyl ether, propylene glycol butyl ether, butyl glycol butyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, propylene glycol methyl ether propionate, propylene glycol ethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate and dipropylene glycol methyl ether acetate; or / and, the UV absorber includes at least one of benzophenone compounds, triazine compounds and benzotriazole compounds; or / and, the acrylic resin includes at least one of polyurethane acrylic resin, silicone acrylic resin and polyester acrylic resin.

[0016] In a second aspect, the present application provides a method for preparing a coating liquid for preparing a UV barrier film as provided in the first aspect above, the preparation method comprising: mixing a UV absorber and a sol to obtain a UV absorbing matrix; and then stirring and mixing a system containing the UV absorbing matrix, an acrylic resin and a solvent.

[0017] In the method for preparing a coating liquid for preparing a UV-blocking film provided in the present application, a UV absorber and a sol are first mixed, so that at least a portion of the UV absorber can be encapsulated by the sol; then, a system containing a UV-absorbing matrix, an acrylic resin, and a solvent is stirred and mixed to form a coating liquid. During the process of curing the coating liquid to form a UV-blocking film, the sol has an encapsulating effect on the UV absorber, and in combination with the ether-alcohol solvent in the coating liquid, it can inhibit the UV absorber encapsulated by the sol from floating to the upper region of the coating liquid. In addition, the sol, as a filler in the coating liquid, can also increase the crosslinking density of the acrylic resin during the curing process of the coating liquid, making the cured UV-blocking film denser. The dense UV-blocking film can inhibit the UV absorber from precipitating on the surface of the UV-blocking film, thereby improving the UV-blocking function of the UV-blocking film and effectively avoiding precipitation problems during subsequent use.

[0018] In combination with the second aspect, in an optional embodiment of the present application, the method for preparing the UV absorbing matrix includes: stirring and mixing the UV absorber and the sol at a rotation speed of 500-2000 rpm.

[0019] In the above technical solution, the sol and the UV absorber can be in full contact, and the sol wraps the UV absorber more fully, which is beneficial to further inhibit the UV absorber from floating in the upper area of ​​the coating liquid, and further beneficial to further prevent the UV absorber from precipitating on the surface of the UV blocking film, which is beneficial to improve the ultraviolet blocking function of the UV blocking film and avoid precipitation problems during subsequent use.

[0020] In combination with the second aspect, in an optional embodiment of the present application, the system further contains a photoinitiator; or / and, the system further contains a leveling agent; or / and, the system further contains an acrylate monomer.

[0021] In the above technical solution, the photoinitiator is used to initiate the cross-linking of the acrylic resin so that the coating liquid used to prepare the UV barrier film undergoes a curing reaction; the leveling agent is used to make the coating liquid smoother during coating; and the acrylate monomer is used to improve the adhesion performance and adjust the flexibility of the UV barrier film.

[0022] In a third aspect, the present application provides a UV blocking film, which is a solidified product of the coating solution for preparing the UV blocking film provided in the first aspect.

[0023] The UV blocking film provided in this application has good ultraviolet blocking function.

[0024] In a fourth aspect, the present application provides an optical film assembly, which includes a substrate and the UV blocking film provided in the third aspect; the UV blocking film covers the surface of the substrate.

[0025] In a fifth aspect, the present application provides a method for preparing an optical film assembly as provided in the fourth aspect above, comprising: coating the coating liquid for preparing a UV blocking film provided in the first aspect above on the surface of a substrate, and curing the coating liquid for preparing a UV blocking film under ultraviolet light irradiation.

[0026] Since the present application adopts the coating liquid for preparing UV blocking film provided in the first aspect mentioned above to prepare optical film components, the UV adsorbent in the coating liquid is not easy to float to the coating surface during the curing process of the coating liquid, so that the UV blocking film on the substrate surface of the optical film component has better ultraviolet blocking function and avoids precipitation problems during subsequent use.

[0027] In conjunction with the fifth aspect, in an optional embodiment of the present application, the curing step includes: before ultraviolet light irradiation, sequentially subjecting the substrate with the coating liquid coated on its surface to a first heating and a second heating; wherein the temperature of the first heating is 40-80°C, the temperature of the second heating is 80-110°C, and the difference between the lowest temperature of the second heating and the highest temperature of the first heating is ≥15°C. The first heating step includes: subjecting the substrate with the coating liquid coated on its surface to multiple first heat treatments with successively increasing temperatures, the temperature difference between two adjacent first heat treatments being 5-10°C, and the duration of each first heat treatment being 15-25s; the second heating step includes: subjecting the substrate with the coating liquid coated on its surface to at least one second heat treatment, the duration of the second heat treatment being 15-25s.

[0028] In the above technical solution, by controlling the temperature change during the curing of the coating liquid, it is beneficial to further suppress the UV absorber from floating on the upper area of ​​the coating, which is beneficial to further prevent the UV absorber from precipitating on the surface of the UV blocking film, thereby improving the ultraviolet blocking function of the UV blocking film and avoiding precipitation problems during subsequent use.

[0029] Optionally, the difference between the lowest temperature of the second heating and the highest temperature of the first heating is 15-20°C.

[0030] Optionally, the second heating step includes: performing multiple second heat treatments on the substrate coated with the coating liquid at successively increasing temperatures, the temperature difference between two adjacent second heat treatments is 5-10° C., and the duration of each second heat treatment is 15-25 seconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0032] Figure 1 This is a flow chart of the preparation process of the coating liquid for preparing UV blocking film provided in this application. DETAILED DESCRIPTION

[0033] The present application provides a coating liquid for preparing a UV barrier film, which includes a UV absorbing matrix, an acrylic resin and a solvent; wherein the UV absorbing matrix includes a UV absorber and a sol, and at least a portion of the UV absorber is completely wrapped by the sol; and the solvent includes an ether alcohol solvent.

[0034] In this application, UV absorber refers to a substance that can absorb the ultraviolet part of sunlight and fluorescent light sources without changing itself; ether alcohol solvent refers to a solvent containing both ether bonds and hydroxyl groups, or a solvent obtained by esterification reaction of the above substances with carboxylic acid materials.

[0035] In the coating liquid for preparing a UV barrier film provided in the present application, at least a portion of the UV absorber is completely wrapped by the sol. Since the sol has a high specific surface area and adsorption capacity, the sol can wrap the UV absorber more stably; in the process of curing the coating liquid containing acrylic resin to form a UV barrier film, since the sol has a wrapping effect on the UV absorber, the ether-alcohol solvent can inhibit the sol (i.e., the UV absorbing matrix) wrapped with the UV absorber from floating in the upper area of ​​the coating liquid during the drying and volatilization of the coating liquid. Through the mutual cooperation of the sol wrapped with the UV absorber and the ether-alcohol solvent, the UV absorber can be prevented from floating in the upper area of ​​the coating liquid.

[0036] In addition, since the sol itself has a certain bonding strength, the sol acts as a filler in the coating liquid. When the coating liquid is cured, it can also increase the cross-linking density of the acrylic resin during cross-linking and curing, making the UV barrier film formed by the curing denser. The dense UV barrier film can inhibit the UV absorber from precipitating on the surface of the UV barrier film.

[0037] Therefore, the coating liquid for preparing the UV blocking film provided in the present application can inhibit the precipitation of the UV absorber, which is beneficial to improving the ultraviolet blocking function of the UV blocking film and avoiding the precipitation problem during subsequent use.

[0038] In some optional embodiments of the present application, the sol includes at least one of silica sol, alumina sol, and zirconium sol. These sols have high specific surface areas and high adsorption properties, resulting in a more effective and stable encapsulation of the UV adsorbent. Combined with the ether-alcohol solvent in the coating solution, the sol can effectively prevent the UV adsorbent from floating in the upper layer of the coating solution.

[0039] In some optional embodiments of the present application, the ether-alcohol solvent includes at least one of propylene glycol methyl ether, propylene glycol ethyl ether, ethylene glycol butyl ether, propylene glycol butyl ether, butyl glycol butyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, propylene glycol methyl ether propionate, propylene glycol ethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate, and dipropylene glycol methyl ether acetate. These ether-alcohol solvents can effectively prevent the sol coated with the UV absorber (i.e., the UV absorbing matrix) from floating above the coating liquid.

[0040] In some optional embodiments of the present application, the UV absorber includes at least one of a benzophenone compound, a triazine compound, and a benzotriazole compound.

[0041] As an example, the UV absorber may be BASF's product types 479 and 460, or JEDEC's product type BP-6.

[0042] It should be noted that the UV absorber is not limited to the above substances. For example, the UV absorber can also be selected from salicylate compounds or substituted acrylonitrile compounds.

[0043] In some optional embodiments of the present application, the acrylic resin includes at least one of a polyurethane acrylic resin, a silicone acrylic resin, and a polyester acrylic resin. Such acrylic resins can undergo a cross-linking and curing reaction in the presence of ultraviolet light and a photoinitiator to form a film matrix of the UV-blocking film, thereby imparting a certain degree of hardness and wear resistance to the UV-blocking film.

[0044] It should be noted that, in other optional embodiments of the present application, the acrylic resin is not limited to the above substances. For example, the acrylic resin can also be selected from epoxy acrylic resin or aromatic acrylic resin.

[0045] In some optional embodiments of the present application, the acrylic resin is a multifunctional acrylic resin, which has better hardness and wear resistance.

[0046] Furthermore, in some optional embodiments of the present application, the functionality of the acrylic resin is 3-6.

[0047] In some optional embodiments of the present application, the solvent further comprises a non-ether alcohol solvent. The inclusion of both a non-ether alcohol solvent and an ether alcohol solvent is more advantageous in preventing the UV absorbent-coated sol (i.e., the UV absorbing matrix) from floating above the coating liquid during the drying and volatilization process of the coating liquid.

[0048] Illustratively, the non-ether alcohol solvent includes at least one of ethyl acetate, butyl acetate, toluene, xylene, acetone, butanone, cyclohexanone, methyl isobutyl ketone, isopropyl alcohol, and isobutyl alcohol.

[0049] It should be noted that, in other optional embodiments of the present application, the non-ether alcohol solvent is not limited to the above substances. For example, the non-ether alcohol solvent can also be selected from methyl acetate, etc.

[0050] In some optional embodiments of the present application, the solvent is an ether alcohol solvent, that is, the solvent does not contain a non-ether alcohol solvent.

[0051] In some optional embodiments of the present application, the coating solution for preparing the UV-blocking film further comprises a photoinitiator. The photoinitiator is used to initiate cross-linking of the acrylic resin, thereby causing the coating solution for preparing the UV-blocking film to undergo a curing reaction to form a film matrix of the UV-blocking film.

[0052] As an example, the photoinitiator includes at least one of 2-hydroxy-2-methylpropiophenone, 1-hydroxycyclohexylphenyl ketone, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone, 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone and phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide.

[0053] It should be noted that in other optional embodiments of the present application, the photoinitiator is not limited to the above-mentioned substances. For example, the photoinitiator can also be selected from 1,1'-(methylenebis-4,1-phenylene)bis[2-hydroxy-2-methyl-1-propanone] or benzoin dimethyl ether, etc.; the coating liquid for preparing the UV barrier film of the present application may also not contain a photoinitiator. Before using the coating liquid to form the UV barrier film, the coating liquid is first mixed with the photoinitiator.

[0054] In some optional embodiments of the present application, the coating liquid for preparing the UV blocking film further comprises a leveling agent, which is used to make the coating liquid smoother during coating.

[0055] As an example, the leveling agent includes at least one of a fluorine-containing acrylic polymer leveling agent and a polyether leveling agent; for example, the leveling agent is selected from Efka 3777, Kyoreisha 680 or BYK346.

[0056] It should be noted that, in other optional embodiments of the present application, the coating liquid for preparing the UV barrier film of the present application may not contain a leveling agent.

[0057] In some optional embodiments of the present application, the coating solution for preparing the UV-blocking film further comprises an acrylate monomer, which is used to improve the adhesion and flexibility of the UV-blocking film.

[0058] Furthermore, in some optional embodiments of the present application, the functionality of the acrylate monomer is 1 to 3, which has the effects of improving hardness, wear resistance, adhesion and adjusting flexibility.

[0059] Illustratively, the acrylate monomer includes at least one of dipentaerythritol pentaacrylate, pentaerythritol hexaacrylate, pentaerythritol triacrylate, ethoxyethyl acrylate, trihydroxymethylpropane triacrylate, hexanediol diacrylate, and propoxypentanediol diacrylate.

[0060] It should be noted that, in other optional embodiments of the present application, the coating solution for preparing the UV blocking film of the present application may not contain acrylate monomers.

[0061] In some optional embodiments of the present application, the mass ratio of the UV absorber to the sol in the UV absorbing matrix is ​​1:(1-20). This allows the sol to more fully encapsulate the UV absorber, further inhibiting the UV absorber from floating on the upper layer of the coating liquid, thereby further preventing the UV absorber from precipitating on the surface of the UV blocking film, thereby improving the UV blocking function of the UV blocking film and avoiding precipitation problems during subsequent use. As an example, the mass ratio of the UV absorber to the sol can be any value among 1:1, 1:2, 1:5, 1:6, 1:8, 1:10, 1:12, 1:15, 1:17 and 1:20, or a range between any two values.

[0062] Furthermore, in the UV absorbing matrix, the mass ratio of the UV absorber to the sol is 1:(5-10).

[0063] In some optional embodiments of the present application, the coating solution for preparing the UV blocking film includes the following components in parts by weight: 1-10 parts of a UV absorbing matrix, 5-20 parts of an acrylic resin, and 10-100 parts of a solvent.

[0064] The present application regulates the ratio of the components in the coating liquid for preparing the UV barrier film, so that the UV barrier film prepared by using the coating liquid for preparing the UV barrier film has better ultraviolet light blocking function.

[0065] As an example, the weight parts of the UV absorbing matrix can be any value among 1 part, 2 parts, 5 parts, 7 parts, 8 parts and 10 parts, or a range between any two parts; the weight parts of the acrylic resin can be any value among 5 parts, 7 parts, 10 parts, 12 parts, 15 parts, 17 parts and 20 parts, or a range between any two parts; the weight parts of the solvent can be any value among 10 parts, 15 parts, 20 parts, 30 parts, 35 parts, 45 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts and 100 parts, or a range between any two parts.

[0066] Furthermore, in the coating solution for preparing the UV blocking film, the weight portion of the UV absorbing matrix may be 2-8 parts.

[0067] Furthermore, in the coating solution for preparing the UV blocking film, the weight portion of the acrylic resin may be 7-15 parts.

[0068] Furthermore, in the coating solution for preparing the UV blocking film, the weight portion of the solvent may be 20-80 parts.

[0069] In some optional embodiments of the present application, the coating solution for preparing the UV-blocking film further comprises 0.3-2 parts of a photoinitiator. For example, the weight percentage of the photoinitiator may be any of 0.3 parts, 0.5 parts, 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.7 parts, and 2 parts, or any range therebetween.

[0070] Furthermore, in the coating solution for preparing the UV blocking film, the weight portion of the photoinitiator may be 0.6-1 part.

[0071] In some optional embodiments of the present application, the coating solution for preparing the UV-blocking film further comprises 0.01-0.06 parts of a leveling agent. For example, the weight of the leveling agent may be any of 0.01 parts, 0.02 parts, 0.03 parts, 0.04 parts, 0.05 parts, and 0.06 parts, or any range therebetween.

[0072] Furthermore, in the coating solution for preparing the UV barrier film, the weight portion of the leveling agent may be 0.02-0.05 parts.

[0073] In some optional embodiments of the present application, the coating solution for preparing the UV-blocking film further comprises 1-5 parts of an acrylate monomer. For example, the weight percentage of the acrylate monomer may be any of 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, and 5 parts, or any range therebetween.

[0074] Furthermore, in the coating solution for preparing the UV blocking film, the weight portion of the acrylate monomer may be 2-4 parts.

[0075] As mentioned above, the solvents in the coating liquid can be entirely ether-alcohol solvents, or they can contain both ether-alcohol and non-ether-alcohol solvents. In the case where the solvents in the coating liquid contain both ether-alcohol and non-ether-alcohol solvents, the mass ratio of the ether-alcohol to non-ether-alcohol solvents should be ≥ 2:1. This is more effective in preventing the UV absorber-coated sol (i.e., the UV absorbing matrix) from floating to the upper layer of the coating liquid during the drying and volatilization process.

[0076] As an example, in the coating liquid, the mass ratio of the ether alcohol solvent to the non-ether alcohol solvent can be 2:1, 3:1, 4:1, 5:1, 6:1, 7:1 or 8:1, etc.

[0077] Furthermore, the mass ratio of the ether alcohol solvent to the non-ether alcohol solvent is ≥5:1.

[0078] The present application provides a method for preparing the above-mentioned coating liquid for preparing a UV barrier film. Figure 1 For the process flow chart of the coating solution for preparing UV barrier film provided in this application, please refer to Figure 1 The method for preparing a coating liquid for preparing a UV barrier film comprises the following steps:

[0079] S10, mixing the UV absorber and the sol to obtain a UV absorbing matrix.

[0080] In the present application, the UV absorber and the sol are first mixed so that at least a portion of the UV absorber can be wrapped by the sol; the sol has a wrapping effect on the UV absorber, and can then be combined with ether alcohol solvents to inhibit the sol wrapped with the UV absorber (i.e., the UV absorbing matrix) from floating on the upper layer of the coating liquid during the curing process of the coating liquid.

[0081] For the selection and proportion of UV absorber and sol, please refer to the above content and will not be repeated here.

[0082] In some optional embodiments of the present application, the method for preparing the UV absorbing matrix includes: stirring and mixing the UV absorber and the sol at a rotation speed of 500-2000 rpm.

[0083] In the above technical solution, the sol and the UV absorber can be fully in contact, so that the sol can wrap the UV absorber more fully, which is beneficial to further inhibit the UV absorber from floating in the upper area of ​​the coating liquid, and further beneficial to further prevent the UV absorber from precipitating on the surface of the UV blocking film, which is beneficial to improve the ultraviolet blocking function of the UV blocking film and avoid precipitation problems during subsequent use.

[0084] Illustratively, the rotation speed of the UV absorber and the sol is any one of 500 rpm, 750 rpm, 800 rpm, 1000 rpm, 1100 rpm, 1200 rpm, 1400 rpm, 1500 rpm, 1700 rpm and 2000 rpm, or any range between two of them.

[0085] It is understandable that in some other embodiments of the present application, the rotation speed of the mixing of the UV absorber and the sol may not be limited, as long as the mixing is uniform.

[0086] S20, stirring and mixing the system containing the UV absorbing matrix, acrylic resin and solvent.

[0087] For the selection and ratio of acrylic resin and solvent, please refer to the above content and will not be repeated here.

[0088] In some optional embodiments of the present application, the system containing the UV absorbing matrix, acrylic resin and solvent further contains a photoinitiator, a leveling agent and / or an acrylate monomer.

[0089] For the selection and ratio of photoinitiator, leveling agent and acrylate monomer, please refer to the above content and will not be repeated here.

[0090] The present application also provides a UV blocking film, which is a product obtained by curing the coating solution for preparing the UV blocking film provided above.

[0091] The UV blocking film provided in this application has good ultraviolet blocking function. The UV blocking film provided in this application can be attached to the surface of a liquid crystal display device. It is understood that this application does not limit the use of the UV blocking film, and it can be used in any application scenario requiring UV blocking.

[0092] The present application also provides an optical film assembly, which includes a substrate and the UV blocking film provided above; the UV blocking film covers the surface of the substrate.

[0093] It should be noted that this application does not limit the material and thickness of the substrate. The substrate can be a transparent material, such as plastic film, glass, etc.; the substrate can also be an opaque material, such as a colored film, etc.; the thickness of the substrate can be 25-250μm, etc.

[0094] The present application also provides a method for preparing the optical film assembly provided above, which comprises: coating the coating liquid for preparing the UV blocking film provided above on the surface of the substrate, and curing the coating liquid for preparing the UV blocking film under ultraviolet light irradiation.

[0095] Since the present application adopts the coating liquid for preparing UV blocking film provided in the first aspect above to prepare the optical film assembly, the UV adsorbent in the coating liquid is not easy to float out of the upper area of ​​the coating during the curing process of the coating liquid, so that the UV blocking film on the substrate surface of the optical film assembly has better ultraviolet blocking function, and effectively avoids the precipitation problem during subsequent use.

[0096] As an example, the method for preparing an optical film assembly includes applying a coating liquid to a substrate surface, and then curing the coating liquid under ultraviolet light and in the presence of a photoinitiator to form a UV-blocking film, thereby obtaining a substrate and a UV-blocking film covering the substrate surface. This application does not limit the material and shape of the substrate.

[0097] In some optional embodiments of the present application, the step of curing the coating liquid for preparing the UV-blocking film includes: prior to ultraviolet light irradiation, sequentially subjecting the substrate coated with the coating liquid to a first heating and a second heating; wherein the temperature of the first heating is 40-80°C, the temperature of the second heating is 80-110°C, and the difference between the lowest temperature of the second heating and the highest temperature of the first heating is ≥15°C. The first heating step includes: subjecting the substrate coated with the coating liquid to a plurality of first heat treatments at successively increasing temperatures, the temperature difference between two adjacent first heat treatments being 5-10°C, and the duration of each first heat treatment being 15-25 seconds; and the second heating step includes: subjecting the substrate coated with the coating liquid to at least one second heat treatment, the duration of the second heat treatment being 15-25 seconds.

[0098] The present application helps to further inhibit the UV absorber from floating on the upper area of ​​the coating liquid by controlling the temperature change during the drying of the coating liquid solvent, thereby further preventing the UV absorber from floating on the surface of the UV blocking film, thereby improving the ultraviolet blocking function of the UV blocking film and avoiding precipitation problems during subsequent use.

[0099] As an example, the temperature of the first heating can be any value among 40℃, 50℃, 60℃, 70℃ and 80℃, or a range value between any two of them; the temperature of the second heating can be any value among 80℃, 90℃, 100℃ and 110℃, or a range value between any two of them; the difference between the lowest temperature of the second heating and the highest temperature of the first heating can be any value among 15℃, 16℃, 17℃, 18℃, 19℃ and 20℃, or a range value between any two of them; the temperature difference between two adjacent first heat treatments can be any value among 5℃, 6℃, 7℃, 8℃, 9℃ and 10℃, or a range value between any two of them; the time of each first heat treatment can be independently any value among 15s, 17s, 20s, 22s and 25s, or a range value between any two of them; the time of the second heat treatment can be any value among 15s, 17s, 20s, 22s and 25s, or a range value between any two of them.

[0100] In some optional embodiments of the present application, the difference between the lowest temperature of the second heating and the highest temperature of the first heating is 15-20°C. This helps to further suppress the UV absorber from floating in the upper region of the coating liquid, thereby further preventing the UV absorber from floating on the surface of the UV blocking film, thereby improving the UV blocking function of the UV blocking film and avoiding precipitation problems during subsequent use.

[0101] In some optional embodiments of the present application, the second heating step includes: performing multiple second heat treatments on the substrate coated with the coating liquid with successively increasing temperatures, the temperature difference between two adjacent second heat treatments is 5-10°C, and the time for each second heat treatment is 15-25s.

[0102] As an example, the temperature difference between two adjacent second heat treatments can be any value among 5°C, 6°C, 7°C, 8°C, 9°C and 10°C, or a range of values ​​between any two of them.

[0103] In some optional embodiments of the present application, the energy of the ultraviolet light is 400-1000 mJ / cm 2 .

[0104] It is understandable that in other optional embodiments of the present application, the above-mentioned process parameters may not be used in the process of preparing optical film assemblies using the coating liquid for preparing UV blocking films provided by the present application, and the present application does not limit the process parameters of the optical film assembly preparation process.

[0105] To make the purpose, technical solutions and advantages of the examples of the present application clearer, the technical solutions in the examples of the present application will be described clearly and completely below. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0106] Example 1

[0107] This embodiment provides an optical film assembly, which includes a 125 μm transparent PET film and a UV blocking film covering the surface of the PET film. The method for preparing the optical film assembly includes:

[0108] (1) Silica sol and BASF 479 in a mass ratio of 6:1 were mixed and stirred at 1500 rpm for 60 min to obtain a UV absorbing matrix.

[0109] (2) A UV absorbing matrix, hexafunctional resin Changxing Chemical 6145-100, pentaerythritol triacrylate, IGM PI-184, propylene glycol methyl ether acetate, methyl isobutyl ketone and Efka 3777 in a mass ratio of 5:10:2.5:0.8:30:5:0.05 were mixed and stirred at 1200 rpm for 120 minutes to obtain a coating solution.

[0110] (3) The coating liquid was applied to the surface of the PET film. After coating, the film was heated to 40°C, 50°C, 60°C and 70°C for 20 seconds, and then heated to 90°C for 20 seconds. The film was then heated to 600 mJ / cm 2 Perform light curing.

[0111] Example 2

[0112] This embodiment provides an optical film assembly. The difference between this embodiment and embodiment 1 is that: in step (1), the mass ratio of silica sol to BASF 479 is 1:1; in step (2), the mass ratio of UV absorbing matrix, hexafunctional resin Changxing Chemical 6145-100, pentaerythritol triacrylate, IGM PI-184, propylene glycol methyl ether acetate, methyl isobutyl ketone and Efka 3777 is 1.4:10:2.5:0.8:30:5:0.05.

[0113] Example 3

[0114] This embodiment provides an optical film assembly. The difference between this embodiment and embodiment 1 is that: in step (1), the mass ratio of silica sol to BASF 479 is 20:1; in step (2), the mass ratio of UV absorbing matrix, hexafunctional resin Changxing Chemical 6145-100, pentaerythritol triacrylate, IGM PI-184, propylene glycol methyl ether acetate, methyl isobutyl ketone and Efka 3777 is 14.7:10:2.5:0.8:30:5:0.05.

[0115] Example 4

[0116] This embodiment provides an optical film assembly. The difference between this embodiment and embodiment 1 is that the steps for preparing the coating liquid are different and the coating liquid does not contain methyl isobutyl ketone. In this embodiment, the steps for preparing the coating liquid are as follows:

[0117] A UV absorbing matrix, hexafunctional resin Changxing Chemical 6145-100, pentaerythritol triacrylate, IGM PI-184, propylene glycol methyl ether acetate and Efka 3777 in a mass ratio of 5:10:2.5:0.8:35:0.05 were mixed and stirred at 1200 rpm for 120 minutes to obtain a coating solution.

[0118] Example 5

[0119] This embodiment provides an optical film assembly. The difference between this embodiment and embodiment 1 is that the steps for preparing the coating liquid are different, and the coating liquid does not contain pentaerythritol triacrylate. In this embodiment, the steps for preparing the coating liquid are as follows:

[0120] A UV absorbing matrix, hexafunctional resin Changxing Chemical 6145-100, IGM PI-184, propylene glycol methyl ether acetate, methyl isobutyl ketone and Efka 3777 in a mass ratio of 5:12.5:0.8:30:5:0.05 were mixed and stirred at 1200 rpm for 120 minutes to obtain a coating solution.

[0121] Example 6

[0122] This embodiment provides an optical film assembly. The difference between this embodiment and Example 1 is that the silica sol in Example 1 is replaced by aluminum sol.

[0123] Example 7

[0124] This embodiment provides an optical film assembly. The difference between this embodiment and Example 1 is that the propylene glycol methyl ether acetate in Example 1 is replaced by propylene glycol methyl ether.

[0125] Example 8

[0126] This embodiment provides an optical film assembly. The difference between this embodiment and embodiment 1 is that the stirring speed in step (1) is 500 rpm.

[0127] Example 9

[0128] This embodiment provides an optical film assembly. The difference between this embodiment and embodiment 1 is that step (3) is different. In this embodiment, step (3) is as follows:

[0129] The coating liquid was applied to the surface of the PET film. After coating, the film was heated at 40°C, 50°C, 60°C and 70°C for 20 seconds, and then heated at 80°C for 20 seconds. The film was then heated with UV energy of 600 mJ / cm 2 Perform light curing.

[0130] Example 10

[0131] This embodiment provides an optical film assembly. The difference between this embodiment and Example 1 is that the hexafunctional resin Changxing Chemical 6145-10 in Example 1 is replaced by Lida Chemical CB33110.

[0132] Comparative Example 1

[0133] This comparative example provides an optical film assembly. The difference between this comparative example and Example 1 is that in this comparative example, no UV absorbing matrix is ​​prepared, and the steps for preparing the coating liquid are different. The steps for preparing the coating liquid are as follows:

[0134] BASF 479, hexafunctional resin Changxing Chemical 6145-100, pentaerythritol triacrylate, IGM PI-184, propylene glycol methyl ether acetate, methyl isobutyl ketone and Efka 3777 in a mass ratio of 0.7:10:2.5:0.8:30:5:0.05 were mixed and stirred at 1200 rpm for 180 minutes to obtain a coating solution.

[0135] Comparative Example 2

[0136] This comparative example provides an optical film assembly. The difference between this comparative example and Example 1 is that the steps for preparing the coating liquid are different. In this comparative example, the steps for preparing the coating liquid are as follows:

[0137] A UV absorbing matrix, hexafunctional resin Changxing Chemical 6145-100, pentaerythritol triacrylate, IGM PI-184, methyl isobutyl ketone and Efka 3777 in a mass ratio of 5:10:2.5:0.8:35:0.05 were mixed and stirred at 1200 rpm for 180 minutes to obtain a coating solution.

[0138] Comparative Example 3

[0139] This comparative example provides an optical film assembly. The difference between this comparative example and Example 1 is that the steps for preparing the coating liquid are different. In this comparative example, the steps for preparing the coating liquid are as follows:

[0140] Silica sol, BASF 479, hexafunctional resin Changxing Chemical 6145-100, pentaerythritol triacrylate, IGM PI-184, propylene glycol methyl ether acetate, methyl isobutyl ketone and Efka 3777 in a mass ratio of 4.3:0.7:10:2.5:0.8:30:5:0.05 were mixed and stirred at 1200 rpm for 180 minutes to obtain a coating solution.

[0141] Experimental example

[0142] The optical film assemblies prepared in Examples 1-10 and Comparative Examples 1-3 were subjected to spectral tests, and the test results are shown in Table 1.

[0143] The spectral test method is as follows: Cut the prepared optical film assembly into 5cm x 5cm sheets. Set the CM3600A spectrophotometer to transmission mode and perform calibration. After calibration, place the sheet in the transmission sample holder for testing. After the test, record the transmittance and b* value of the optical film assembly at 380nm.

[0144] The spectral test also includes subjecting the optical film assembly to the following conditions: A, B, C, D, and E (simulating different post-use conditions), followed by spectral testing. Condition A: The optical film assembly is stored in a 150°C oven for 10 days. Condition B: The optical film assembly is stored in a -40°C to 80°C high and low temperature alternating humidity test chamber for 10 days. Condition C: The optical film assembly is stored in an 85°C, 85% RH constant temperature and humidity test chamber for 10 days. Condition D: The optical film assembly is soaked in a 10wt% sodium hydroxide aqueous solution for 10 minutes, then rinsed with clean water and the surface dried. Condition E: The optical film assembly is soaked in a 10wt% hydrochloric acid aqueous solution for 10 minutes, then rinsed with clean water and the surface dried.

[0145] Table 1

[0146]

[0147] As can be seen from Table 1, the UV blocking effects of the optical film assemblies prepared in Examples 1-10 of the present application after simulating different later use conditions (i.e., Condition A, Condition B, Condition C, Condition D, and Condition E) are significantly better than those of the optical film assemblies prepared in Comparative Examples 1-3, indicating that the optical film assemblies prepared in Examples 1-10 of the present application can better avoid the problem of precipitation of UV blocking film during later use.

[0148] From the comparison of Examples 1-3, it can be seen that the ratio of silica sol to UV absorber can further affect the UV blocking effect of the optical film assembly after simulating different post-use conditions (i.e., Condition A, Condition B, Condition C, Condition D, Condition E).

[0149] From the comparison between Example 1 and Example 4, it can be seen that when the solvent of the coating liquid contains both non-ether alcohol solvents and ether alcohol solvents, it is more conducive to improving the UV blocking effect of the optical film assembly after simulating different later use conditions (i.e., Condition A, Condition B, Condition C, Condition D, Condition E).

[0150] From the comparison between Example 1 and Example 5, it can be seen that the presence or absence of pentaerythritol triacrylate (i.e., acrylate monomer) in the coating liquid can make the optical film assembly have better UV blocking effect after simulating different later use conditions (i.e., Condition A, Condition B, Condition C, Condition D, Condition E); the presence of pentaerythritol triacrylate (i.e., acrylate monomer) in the coating liquid is conducive to further improving the UV blocking effect.

[0151] From the comparison between Example 1 and Example 6, it can be seen that the sol in the coating liquid is silica sol or aluminum sol, both of which can make the optical film assembly have better UV blocking effect after simulating different later use conditions (i.e., condition A, condition B, condition C, condition D, condition E), indicating that the specific selection of sol in the coating liquid has little effect on the UV blocking effect.

[0152] From the comparison between Example 1 and Example 7, it can be seen that the ether alcohol solvents in the coating liquid are propylene glycol methyl ether acetate and propylene glycol methyl ether, both of which can make the optical film assembly have better UV blocking effect after simulating different later use conditions (i.e., Condition A, Condition B, Condition C, Condition D, Condition E), indicating that the specific selection of the ether alcohol solvent in the coating liquid has little effect on the UV blocking effect.

[0153] From the comparison between Example 1 and Example 8, it can be seen that the stirring speed of the sol and the UV absorber can further affect the UV blocking effect of the optical film assembly after simulating different later use conditions (i.e., Condition A, Condition B, Condition C, Condition D, Condition E).

[0154] From the comparison between Example 1 and Example 9, it can be seen that the heating method of the coating liquid before ultraviolet light irradiation can further affect the UV blocking effect of the optical film assembly after simulating different later use conditions (i.e., Condition A, Condition B, Condition C, Condition D, Condition E), indicating that: when the temperature difference of heating changes significantly, the precipitation problem of the UV blocking film during later use can be better avoided.

[0155] From the comparison between Example 1 and Example 10, it can be seen that the acrylic resin in the coating liquid is the hexafunctional resin Changxing Chemical 6145-10 or Lida Chemical CB33110, both of which can make the optical film assembly have better UV blocking effect after simulating different later use conditions (i.e., Condition A, Condition B, Condition C, Condition D, Condition E), indicating that the specific selection of the acrylic resin in the coating liquid has little effect on the UV blocking effect.

[0156] In summary, in the coating liquid for preparing UV barrier film provided by the present application, the sol has a wrapping effect on the UV absorber, and combined with the ether alcohol solvents in the coating liquid, it can inhibit the UV absorber wrapped by the sol from floating in the upper area of ​​the coating liquid; in addition, the sol serves as a filler in the coating liquid. During the curing process of the coating liquid, it can also increase the cross-linking density of the acrylic resin, so that the UV barrier film formed by the curing is denser. The dense UV barrier film can inhibit the UV absorber from precipitating on the surface of the UV barrier film, which is beneficial to avoid the precipitation problem of the UV barrier film during later use.

[0157] The embodiments described above are part of the embodiments of the present application, rather than all of the embodiments. The detailed description of the embodiments of the present application is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

Claims

1. A coating solution for preparing a UV barrier film, characterized in that: The coating liquid for preparing the UV barrier film comprises a UV absorbing matrix, an acrylic resin and a solvent; The UV absorbing matrix comprises a UV absorber and a sol, and at least a portion of the UV absorber is completely wrapped by the sol; the preparation method of the UV absorbing matrix comprises: mixing the UV absorber and the sol to obtain the UV absorbing matrix; The solvent includes an ether alcohol solvent.

2. The coating solution for preparing a UV barrier film according to claim 1, characterized in that: The coating solution for preparing the UV barrier film includes the following components in parts by weight: 1-10 parts of the UV absorbing matrix, 5-20 parts of the acrylic resin, and 10-100 parts of the solvent; Wherein, in the UV absorbing matrix, the mass ratio of the UV absorber to the sol is 1:(1-20).

3. The coating solution for preparing a UV barrier film according to claim 2, characterized in that: The solvent further comprises a non-ether alcohol solvent, and the mass ratio of the ether alcohol solvent to the non-ether alcohol solvent is ≥2:

1.

4. The coating solution for preparing a UV barrier film according to claim 3, characterized in that: The non-ether alcohol solvent includes at least one of ethyl acetate, butyl acetate, toluene, xylene, acetone, butanone, cyclohexanone, methyl isobutyl ketone, isopropyl alcohol and isobutanol.

5. The coating solution for preparing a UV barrier film according to claim 2, characterized in that: The coating solution for preparing the UV blocking film further comprises 0.3-2 parts of a photoinitiator.

6. The coating solution for preparing a UV barrier film according to claim 2, characterized in that: The coating solution for preparing the UV barrier film further comprises 0.01-0.06 parts of a leveling agent.

7. The coating solution for preparing a UV barrier film according to claim 2, characterized in that: The coating solution for preparing the UV blocking film further comprises 1-5 parts of an acrylate monomer.

8. The coating solution for preparing a UV barrier film according to claim 1 or 2, characterized in that: The sol includes at least one of silica sol, aluminum sol and zirconium sol; or / and, the ether alcohol solvent includes at least one of propylene glycol methyl ether, propylene glycol ethyl ether, ethylene glycol butyl ether, propylene glycol butyl ether, butyl glycol butyl ether, dipropylene glycol methyl ether, propylene glycol methyl ether acetate, propylene glycol methyl ether propionate, propylene glycol ethyl ether acetate, ethylene glycol ethyl ether acetate, ethylene glycol butyl ether acetate and dipropylene glycol methyl ether acetate; Or / and, the UV absorber comprises at least one of a benzophenone compound, a triazine compound and a benzotriazole compound; Or / and, the acrylic resin includes at least one of polyurethane acrylic resin, silicone acrylic resin and polyester acrylic resin.

9. The method for preparing a coating solution for preparing a UV barrier film according to any one of claims 1 to 8, wherein: include: The system containing the UV absorbing matrix, the acrylic resin and the solvent is stirred and mixed.

10. The preparation method according to claim 9, characterized in that The preparation method of the UV absorbing matrix comprises: stirring and mixing the UV absorber and the sol at a rotation speed of 500-2000 rpm.

11. The preparation method according to claim 9 or 10, characterized in that: The system also contains a photoinitiator; Or / and, the system further contains a leveling agent; Alternatively or additionally, the system further comprises an acrylate monomer.

12. A UV blocking film, characterized in that: The UV blocking film is a solidified product of the coating solution for preparing a UV blocking film according to any one of claims 1 to 8.

13. An optical film assembly, characterized in that: The optical film assembly comprises a substrate and the UV blocking film according to claim 12; the UV blocking film covers the surface of the substrate.

14. A method for preparing an optical film assembly, characterized in that: include: Applying the coating liquid for preparing a UV barrier film according to any one of claims 1 to 8 on a surface of a substrate, and curing the coating liquid for preparing a UV barrier film under ultraviolet light; The curing step comprises: before the ultraviolet light irradiation, sequentially performing a first heating and a second heating on the substrate with the coating liquid coated on the surface; The temperature of the first heating is 40-80°C, the temperature of the second heating is 80-110°C, and the difference between the lowest temperature of the second heating and the highest temperature of the first heating is ≥15°C.

15. The preparation method according to claim 14, characterized in that The first heating step comprises: performing a plurality of first heat treatments on the substrate coated with the coating liquid at successively increasing temperatures, wherein the temperature difference between two adjacent first heat treatments is 5-10° C., and the duration of each first heat treatment is 15-25 seconds; The second heating step includes: performing at least one second heat treatment on the substrate with the coating liquid coated on the surface thereof, and the time for the second heat treatment is 15-25 seconds.

16. The preparation method according to claim 15, characterized in that The difference between the lowest temperature of the second heating and the highest temperature of the first heating is 15-20°C.

17. The preparation method according to claim 15, characterized in that The second heating step includes: performing multiple second heat treatments on the substrate coated with the coating liquid with successively increasing temperatures, the temperature difference between two adjacent second heat treatments is 5-10° C., and the duration of each second heat treatment is 15-25 seconds.

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