Coatings and display panels

Abstract

The present application provides a coating film and a display panel, wherein the coating film includes a tetrafunctional polyurethane acrylate oligomer, and the tetrafunctional polyurethane acrylate oligomer includes a structure as shown below: The coating film provided in the present application can enhance adhesion to polymethyl methacrylate film.

Description

Technical Field

[0001] The present application relates to the technical field of polymer materials, and in particular to a coating film and a display panel. Background Art

[0002] Polymethyl methacrylate (PMMA) is a typical thermoplastic amorphous polymer with a uniform texture and an internal molecular arrangement that does not affect the passage of light. Therefore, it has excellent optical properties and has great application prospects in the display field.

[0003] However, the surface hardness of PMMA film is generally insufficient. When applied to the outer surface of the display, it is easily scratched by hard objects and affects its optical effect. Therefore, the surface of PMMA film needs to be hardened.

[0004] However, due to the molecular structure of PMMA It can be seen that there are only ester groups with relatively low polarity in its molecular structure, while the functionality of the hardened coating is usually relatively high. The hardened coating formed directly on the PMMA surface has large internal stress, resulting in poor adhesion between the hardened coating and the PMMA film. Summary of the Invention

[0005] In view of this, the present application provides a coating film and a display panel that can enhance adhesion to PMMA film.

[0006] An embodiment of the present application provides a coating film, wherein the coating film includes a tetrafunctional polyurethane acrylate oligomer, and the tetrafunctional polyurethane acrylate oligomer includes the following structure:

[0007] .

[0008] In one embodiment of the present application, the coating film further includes nano-silicon dioxide particles.

[0009] In one embodiment of the present application, the nano-silica particles include nano-silica particles modified with isocyanoethyl acrylate.

[0010] In one embodiment of the present application, the particle size of the nano-silica particles is 10-1000 nanometers.

[0011] In one embodiment of the present application, the coating film further comprises a first photoinitiator;

[0012] Wherein, the coating film comprises 80 to 120 parts by weight of the tetrafunctional polyurethane acrylate oligomer;

[0013] 1 to 10 parts by weight of the nano-silica particles; and

[0014] 1 to 10 parts by weight of the first photoinitiator.

[0015] The present invention provides a coating film comprising:

[0016] The first sub-coating film includes a tetrafunctional polyurethane acrylate oligomer, and the tetrafunctional polyurethane acrylate oligomer includes the following structure:

[0017] ; and a second sub-coating film, wherein the second sub-coating film is arranged on the surface of the first sub-coating film.

[0018] In one embodiment of the present application, the first sub-coating film further includes nano-silicon dioxide particles.

[0019] In one embodiment of the present application, the nano-silica particles include nano-silica particles modified with isocyanoethyl acrylate.

[0020] In one embodiment of the present application, the particle size of the nano-silica particles is 10-1000 nanometers.

[0021] In one embodiment of the present application, the first sub-coating film further includes a first photoinitiator;

[0022] Wherein, the first sub-coating film comprises 80 to 120 parts by weight of the tetrafunctional polyurethane acrylate oligomer;

[0023] 1 to 10 parts by weight of the nano-silica particles; and

[0024] 1 to 10 parts by weight of the first photoinitiator.

[0025] In one embodiment of the present application, the second sub-coating film includes a polyurethane acrylate oligomer having a functionality greater than or equal to six.

[0026] In one embodiment of the present application, the second sub-coating film includes a decafunctional polyurethane acrylate oligomer, and the decafunctional polyurethane acrylate oligomer includes the following structure:

[0027] .

[0028] In one embodiment of the present application, the second sub-coating film further comprises an acrylate monomer having a functionality greater than or equal to three and a second photoinitiator;

[0029] Wherein, the second sub-coating film comprises 80 to 120 parts by weight of the decafunctional polyurethane acrylate oligomer;

[0030] 10 to 30 parts by weight of the acrylate monomer having a functionality greater than or equal to three; and

[0031] 1 to 10 parts by weight of the second photoinitiator.

[0032] In one embodiment of the present application, the thickness of the first sub-coating film is 10-1000 nanometers, and the thickness of the second sub-coating film is 1-10 micrometers.

[0033] The present application also provides a display panel, including:

[0034] Panel body;

[0035] a polymethyl methacrylate film, the polymethyl methacrylate film being disposed on a surface of the panel body; and

[0036] The coating film described in the above embodiment is provided on the surface of the polymethyl methacrylate film away from the panel body.

[0037] Since the coating provided in the present application includes a tetrafunctional polyurethane acrylate oligomer of the structure shown, the larger number of NH parts contained in its molecular structure can form hydrogen bonds with the O atoms on the ester group in the PMMA molecular structure, thereby enhancing the intermolecular interaction between the coating and PMMA, thereby improving the adhesion of the coating to the PMMA film. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 Schematic diagram of the positional relationship between the coating film and the PMMA film provided in the embodiment of the present application.

[0039] Figure 2 Schematic diagram of a display panel provided in an embodiment of the present application. DETAILED DESCRIPTION

[0040] The present application provides a coating film and a display panel. The various embodiments of the present application are described in the form of a range simply for convenience and brevity, and should not be understood as a hard limit to the scope of the present application. Therefore, the description of the range includes all possible sub-ranges and single numerical values ​​within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the numbered ranges, such as 1, 2, 3, 4, 5 and 6. In addition, the numerical ranges herein include any quoted numbers (fractions or integers) within the indicated ranges.

[0041] An embodiment of the present application provides a coating film, which is arranged on a surface of a thin film. Specifically, the material of the thin film is polymethyl methacrylate (PMMA), which can be arranged on the outside of a display panel to protect the display panel. The thickness of the coating film can be 10 to 1000 nanometers, specifically, the thickness of the coating film can be 20 to 500 nanometers, more specifically, the thickness of the coating film can be 50 to 200 nanometers. The coating film can be formed on a surface of the thin film by a winding coating method. Specific examples of the winding coating method include, but are not limited to: roller coating, gravure coating, reverse coating, roller brushing, dip coating, spray coating, spin coating, pneumatic doctor blade coating, and mold coating methods.

[0042] The coating film includes a tetrafunctional polyurethane acrylate oligomer, and the tetrafunctional polyurethane acrylate oligomer includes the structure shown below:

[0043] .

[0044] Since the molecular structure of the tetrafunctional polyurethane acrylate oligomer shown contains a large number of NH structures, the NH structures can form hydrogen bonds with the O atoms on the ester groups in the PMMA molecular structure, thereby enhancing the intermolecular interaction between the coating and PMMA, thereby improving the adhesion of the coating to the PMMA film.

[0045] The coating also includes nano-silica particles. The surface of the nano-silica particles is rich in hydroxyl groups, which can form hydrogen bonds with the O atoms on the ester groups in the PMMA molecular structure, further strengthening the intermolecular interaction between the coating and PMMA, thereby further improving the coating's adhesion to the PMMA film.

[0046] The nano-silica particles include nano-silica particles modified with isocyanoethyl acrylate. Specifically, the isocyanoethyl acrylate chemically modifies the nano-silica particles by reacting with hydroxyl groups on their surfaces. Since the isocyanoethyl acrylate-modified nano-silica particles contain acryloyloxy groups on their surfaces, they react with the acryloyloxy groups of the tetrafunctional urethane acrylate oligomers in the coating to form cross-links. This further enhances the bonding strength between the nano-silica particles and the tetrafunctional urethane acrylate oligomers in the coating, improving the mechanical properties of the coating and thereby increasing the hardness of the coating.

[0047] The nano-silica particles modified with isocyanoethyl acrylate are partially modified, meaning that isocyanoethyl acrylate only reacts with some of the hydroxyl groups on the surface of the nano-silica particles to chemically modify them. For the nano-silica particles partially modified with isocyanoethyl acrylate, the unmodified hydroxyl groups can form hydrogen bonds with the O atoms on the ester group in the PMMA molecular structure, further strengthening the intermolecular interaction between the coating and PMMA, thereby further improving the adhesion to the PMMA film. At the same time, the surface modified with isocyanoethyl acrylate contains acryloyloxy groups, which can react with the acryloyloxy groups of the tetrafunctional polyurethane acrylate oligomer in the coating to form crosslinks, further enhancing the bonding between the nano-silica particles and the tetrafunctional polyurethane acrylate oligomer in the coating, thereby improving the mechanical properties of the coating. In addition, since the isocyanate ethyl acrylate molecule itself has a certain steric hindrance, it is difficult to completely modify the hydroxyl groups rich in the surface of the nano-silica particles. The degree of modification of the hydroxyl groups on the surface of the nano-silica particles by isocyanate ethyl acrylate can also be controlled by adjusting the ratio between the isocyanate ethyl acrylate molecules and the nano-silica particles.

[0048] The particle size of the nano-silica particles is 10 to 1000 nanometers. Specifically, the particle size of the nano-silica particles is 20 to 500 nanometers, and more specifically, the particle size of the nano-silica particles is 50 to 200 nanometers. The particle size of the nano-silica particles is 10 to 1000 nanometers, which does not significantly affect the transmission of light and can maintain the display effect when used in display panels.

[0049] The coating also includes a first photoinitiator. Under irradiation, the first photoinitiator absorbs energy of a certain wavelength, generating reactive intermediates such as free radicals and cations capable of initiating polymerization. This in turn triggers polymerization and crosslinking reactions of the prepolymer and monomer components, ultimately achieving curing. Specifically, the first photoinitiator can include one or more of Type I and Type II photoinitiators. Type I (cleavage-type) photoinitiators generate free radicals by decomposing molecules due to differences in chemical structure or molecular binding energy. Specific examples of Type I photoinitiators include, but are not limited to, one or more of the following compounds: acetophenones such as 4-phenoxydichloroacetophenone, 4-tert-butyldichloroacetophenone, 4-tert-butyltrichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, and 1-hydroxycyclohexylphenylketone; benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzyl dimethyl ketal; acylphosphine oxides, and titanocene compounds. Type II (hydrogen abstraction) photoinitiators, upon absorbing energy, undergo bimolecular reactions in their excited state with a co-initiator (i.e., a hydrogen donor, such as a tertiary amine) to generate active free radicals. Specific examples of type II photoinitiators include, but are not limited to, one or more of the following compounds: benzophenone compounds such as benzophenone, benzoylbenzoic acid, benzoylbenzoic acid methyl ether, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3'-dimethyl-4-methoxybenzophenone, etc.; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, etc.

[0050] The coating film comprises 80-120 parts by weight of a tetrafunctional urethane acrylate oligomer, 1-10 parts by weight of nano-silica particles, and 1-10 parts by weight of a first photoinitiator. "Parts by weight" refers to the mass of each component added. The actual weight of each "part" is not particularly limited and can be 1 gram, 5 grams, 10 grams, 1 kilogram, 5 kilograms, 10 kilograms, etc., and can be adjusted based on actual production scale requirements, as long as the ratio of the components is maintained. Specifically, the mass of the tetrafunctional urethane acrylate oligomer: the mass of the nano-silica particles: the mass of the first photoinitiator = (80-120): (1-10): (1-10). The above ratios are based on the tetrafunctional urethane acrylate oligomer. The ratios of the other components relative to the tetrafunctional urethane acrylate oligomer can be freely adjusted within the listed ranges as needed. Adjusting the ratio of one component does not affect the ratios of the other components.

[0051] To facilitate coating, the coating film of the present application also includes a solvent. Specifically, the coating film may include 4,000 to 5,000 parts by weight of solvent, i.e., based on the tetrafunctional urethane acrylate oligomer, the mass of the tetrafunctional urethane acrylate oligomer: the mass of the solvent = (80-120): (4,000-5,000). The solvent ratio relative to the tetrafunctional urethane acrylate oligomer can be freely adjusted within the listed range as needed. Specific examples of the solvent include, but are not limited to, one or more of the following: alcohols such as methanol, ethanol, and isopropanol; esters such as ethyl acetate, propyl acetate, and butyl acetate; ketones such as acetone, butanone, and cyclohexanone; and benzenes such as toluene and xylene. The boiling point of the solvent may be 50 to 150 degrees Celsius. Specifically, when the boiling point of the solvent is lower than 50 degrees Celsius, the solvent is highly volatile and the thickness of the coating 10 formed by coating will be affected; when the boiling point of the solvent is higher than 150 degrees Celsius, the drying process of the solvent will become difficult, which will affect the formation efficiency of the coating 10 and increase the process cost.

[0052] Please refer to Figure 1 , an embodiment of the present application provides a coating film 100, including a first sub-coating film 10, the first sub-coating film 10 is the same as the coating film described in the aforementioned embodiment, and a second sub-coating film 20, the second sub-coating film 20 is arranged on the surface of the first sub-coating film 10 away from the film Sub. The second sub-coating film 20 can be a coating with a certain hardness, thereby providing a certain hardness and wear resistance to the film Sub. The thickness of the first sub-coating film 10 can be 10~1000 nanometers, specifically, the thickness of the first sub-coating film 10 can be 20~500 nanometers, more specifically, the thickness of the first sub-coating film 10 can be 50~200 nanometers. The thickness of the second sub-coating film 20 can be 1~10 microns, specifically, the thickness of the second sub-coating film 20 can be 2~8 microns, more specifically, the thickness of the second sub-coating film 20 can be 3~6 microns. The second sub-coating film 20 can be formed on the side surface of the first sub-coating film 10 away from the film Sub by a winding coating method. Specific examples of web coating methods include, but are not limited to, roll coating, gravure coating, reverse coating, roller brushing, dip coating, spray coating, spin coating, air knife coating, and die coating.

[0053] Since the first sub-coating 10 included in the coating 100 is the same as the coating provided in the aforementioned embodiment of the present application, the adhesion of the coating 100 to the PMMA film is improved; and when the second sub-coating 20 contains a component with higher functionality, compared with directly forming the PMMA film surface, the second sub-coating 20 has smaller intramolecular stress when formed on the surface of the first sub-coating 10, so the second sub-coating 20 is not prone to shrinkage, warping, cracking and other defects, further improving the overall adhesion of the coating 100 to the PMMA film.

[0054] The second sub-coating 20 includes a polyurethane acrylate oligomer having a functionality greater than or equal to six. Specifically, a higher functionality has a higher photocuring activity, which helps to increase the crosslinking density. The second sub-coating 20 includes a polyurethane acrylate oligomer having a functionality greater than or equal to six, which enables the second sub-coating 20 to form a denser crosslinking structure after photocuring, thereby improving the mechanical properties of the second sub-coating 20 and thereby increasing the hardness of the second sub-coating 20.

[0055] The second sub-coating film 20 includes a ten-functionality polyurethane acrylate oligomer, and the ten-functionality polyurethane acrylate oligomer includes a structure as shown below:

[0056] .

[0057] Because the decafunctional urethane acrylate oligomer of the structure shown has multiple carbon ring structures introduced into its molecular structure, the overall rigidity of the molecular structure is further enhanced, further improving the mechanical properties of the second sub-coating film 20, thereby further improving the hardness of the second sub-coating film 20. At the same time, the decafunctional urethane acrylate oligomer and the tetrafunctional urethane acrylate oligomer in the first sub-coating film 10 have a partially identical molecular structure, further enhancing the intermolecular forces between the second sub-coating film 20 and the first sub-coating film 10, thereby improving the closeness and adhesion between the second sub-coating film 20 and the first sub-coating film 10.

[0058] The second sub-coating 20 also includes an acrylate monomer with a functionality greater than or equal to three, which can dissolve and dilute the polyurethane acrylate oligomer with a functionality greater than or equal to six in the second sub-coating 20, adjust the viscosity of the component, and participate in the curing process to adjust the curing rate and cross-linking properties of the second sub-coating 20. Specifically, specific examples of acrylate monomers having a functionality greater than or equal to three in the present application include, but are not limited to, one or more of trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, glycerol tri(meth)acrylate, pentaerythritol tri(meth)acrylate, di(trimethylolpropane) tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, di(trimethylolpropane) tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, di(trimethylolpropane) penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and di(trimethylolpropane) hexa(meth)acrylate.

[0059] The second sub-coating 20 also includes a second photoinitiator. Under irradiation from a light source, the second photoinitiator absorbs energy of a certain wavelength and generates reactive intermediates such as free radicals and cations capable of initiating polymerization, thereby initiating polymerization and crosslinking reactions of the prepolymer and monomer components, ultimately achieving curing. Specifically, the second photoinitiator can include one or more of a Type I photoinitiator and a Type II photoinitiator. Specific examples of type I photoinitiators include, but are not limited to, one or more of the following compounds: acetophenones such as 4-phenoxydichloroacetophenone, 4-tert-butyldichloroacetophenone, 4-tert-butyltrichloroacetophenone, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)-phenyl(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexylphenylketone; benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzyl dimethyl ketal, etc.; acylphosphine oxides and titanocene compounds. Specific examples of type II photoinitiators include, but are not limited to, one or more of the following compounds: benzophenone compounds such as benzophenone, benzoylbenzoic acid, benzoylbenzoic acid methyl ether, 4-phenylbenzophenone, hydroxybenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3'-dimethyl-4-methoxybenzophenone, etc.; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, etc.

[0060] The second sub-coating 20 comprises 80-120 parts by weight of a polyurethane acrylate oligomer with a functionality greater than or equal to six, 10-30 parts by weight of an acrylate monomer with a functionality greater than or equal to three, and 1-10 parts by weight of a second photoinitiator. "Parts by weight" refers to the mass of each component added. The actual weight of each "part" is not particularly limited and can be 1 gram, 5 grams, 10 grams, 1 kilogram, 5 kilograms, 10 kilograms, etc., and can be adjusted based on the actual production scale requirements, as long as the ratio of the components is maintained. Specifically, the mass of the polyurethane acrylate oligomer with a functionality greater than or equal to six: the mass of the acrylate monomer with a functionality greater than or equal to three: the mass of the second photoinitiator = (80-120): (10-30): (1-10). The above ratios can be based on the polyurethane acrylate oligomer with a functionality greater than or equal to six. The ratios of various other components relative to the polyurethane acrylate oligomer with a functionality greater than or equal to six can be freely adjusted according to needs within the listed ranges. Adjustment of the ratio of one component does not affect the adjustment of the ratio of another component.

[0061] To facilitate coating, the second sub-coating film 20 of the present application also includes a solvent. Specifically, the second sub-coating film 20 may include 200-300 parts by weight of solvent. This means that, based on the polyurethane acrylate oligomer with a functionality greater than or equal to six, the mass of the polyurethane acrylate oligomer with a functionality greater than or equal to six: the mass of the solvent = (80-120): (200-300). The solvent ratio relative to the polyurethane acrylate oligomer with a functionality greater than or equal to six can be freely adjusted within the listed range as needed. Specific examples of the solvent include, but are not limited to, one or more of the following: alcohols such as methanol, ethanol, and isopropanol; esters such as ethyl acetate, propyl acetate, and butyl acetate; ketones such as acetone, butanone, and cyclohexanone; and benzenes such as toluene and xylene. The boiling point of the solvent may be 50-150 degrees Celsius. Specifically, when the boiling point of the solvent is lower than 50 degrees Celsius, the solvent is highly volatile and the thickness of the coating 10 formed by coating will be affected; when the boiling point of the solvent is higher than 150 degrees Celsius, the drying process of the solvent will become difficult, which will affect the formation efficiency of the coating 10 and increase the process cost.

[0062] Please refer to Figure 2 The present embodiment provides a display panel 200, comprising: a panel body 110; a polymethyl methacrylate film 120 disposed on one surface of the panel body 110; and the coating film 100 described in the preceding embodiment, disposed on a surface of the polymethyl methacrylate film 120 away from the panel body 110. The panel body 110 may be an organic light-emitting diode (OLED) display panel, a quantum dot light-emitting diode (QLED) display panel, a micro-LED display panel, a sub-millimeter light-emitting diode (Mini-LED) display panel, or a liquid crystal display panel.

[0063] Since the coating film 100 provided in the aforementioned embodiment has stronger adhesion to the polymethyl methacrylate (PMMA) film, in the display panel 200, the coating film 100 can be firmly and durably adhered to the surface of the polymethyl methacrylate film 120 without being susceptible to defects such as shrinkage, warping, and cracking, thereby better protecting the entire surface of the display panel 200 and improving the durability of the display panel 200.

[0064] Hereinafter, the coating film and display panel of the present application will be described through specific embodiments.

[0065] Synthesis of Tetrafunctional Polyurethane Acrylate Oligomer P1

[0066]

[0067] first step:

[0068]

[0069] 5 g of norbornane dimethylamine and 15 g of isophorone diisocyanate were dissolved in 10 g of dichloromethane, and then 0.1 g of bismuthic acid catalyst was added. The mixture was reacted in a nitrogen atmosphere at 60 degrees Celsius for 4 hours to obtain an isocyanate-terminated prepolymer A1.

[0070] Step 2:

[0071]

[0072] 10 g of trimethylolpropane diallyl ether and 20 g of the prepolymer A1 obtained in the first step were dissolved in 10 g of methyl ethyl ketone, and then 0.1 g of bismuth acid catalyst was added. The mixture was reacted in a nitrogen atmosphere at 60 degrees Celsius for 4 hours to obtain a tetrafunctional polyurethane acrylate oligomer P1.

[0073] Preparation of Nanosilica Particles Modified with Isocyanoethyl Acrylate

[0074]

[0075] 5 g of nano-silica particles were added to 10 g of butyl acetate, stirred and dispersed by ultrasonic vibration, and then 0.5 g of isocyanoethyl acrylate and 0.01 g of dibutyltin dilaurate (DBTDL) were added. The mixture was reacted at 60 degrees Celsius for 20 hours to obtain a dispersion of nano-silica particles modified with isocyanoethyl acrylate.

[0076] Synthesis of Decafunctional Polyurethane Acrylate Oligomer P2

[0077]

[0078] first step:

[0079]

[0080] 5 g of norbornane dimethylamine and 15 g of isophorone diisocyanate were dissolved in 10 g of dichloromethane, and then 0.1 g of bismuthic acid catalyst was added. The mixture was reacted in a nitrogen atmosphere at 60 degrees Celsius for 4 hours to obtain an isocyanate-terminated prepolymer A1.

[0081] Step 2:

[0082]

[0083] 15 g of polyisopentyl glycol pentaacrylate and 20 g of the prepolymer A1 obtained in the first step were dissolved in 10 g of methyl ethyl ketone, and then 0.1 g of bismuth acid catalyst was added. The mixture was reacted in a nitrogen atmosphere at 60 degrees Celsius for 4 hours to obtain a ten-functional polyurethane acrylate oligomer P2.

[0084] Example 1: Preparation of hard coating film HC1

[0085] Preparation of the first sub-coating: The first sub-coating composition is roller-coated on the PMMA film, and the solvent is first dried in an oven at a temperature of 60-120 degrees Celsius; then the film is cured by UV light at an energy of 100-1000 mJ / cm 2 The thickness of the formed coating is 50~200 nanometers.

[0086] Preparation of the second sub-coating film: The second sub-coating film composition is roller-coated on the formed first sub-coating film, and the solvent is first dried in an oven with the oven temperature set at 60-120 degrees Celsius; then it is cured by ultraviolet light with an ultraviolet curing energy of 100-1000mJ / cm 2 The thickness of the second sub-coating formed is 3~6 microns.

[0087] The specific components and proportions of the first and second sub-coatings are as follows:

[0088] First sub-coating component:

[0089]

[0090] Second sub-coating component:

[0091]

[0092] Example 2: Preparation of hard coating film HC2

[0093] The hard coating film HC2 can be prepared by the same method as Example 1, except that the specific components and the proportions of the components of the first and second sub-coating films are different. The specific components and the proportions of the components of the first and second sub-coating films are as follows:

[0094] First sub-coating component:

[0095]

[0096] Second sub-coating component:

[0097]

[0098] Performance evaluation of hard coatings

[0099] Adhesion performance was evaluated using the 100-grid method. Specifically, a 10x10 grid of 1mm x 1mm was drawn on the hardcoat surface using a 100-grid cutter. After removing any debris, 3M 100-grid tape was used to securely cover the grid. The tape was then quickly removed vertically to observe any signs of coating shedding.

[0100] Adhesion determination criteria:

[0101] 5B, the edges of the lines are smooth, and there is no coating peeling at the edges and intersections of the lines.

[0102] 4B, small pieces of coating have fallen off at the intersections of the scribe lines, and the total area of ​​the coating has fallen off is less than 5%.

[0103] 3B, small pieces of coating fall off at the edges and intersections of the scribe lines, and the total area of ​​the coating falls off is between 5% and 15%.

[0104] 2B, there are pieces of coating peeling off at the edges and intersections of the scribe lines, and the total peeling area is between 15% and 35%.

[0105] 1B, there are pieces of coating peeling off at the edges and intersections of the scribe lines, and the total peeling area is between 35% and 65%.

[0106] 0B, the shedding area exceeds the 1B standard.

[0107] Pencil hardness performance evaluation: Using Mitsubishi pencils with hardness ranging from H to 9H, the hard coating surface was scratched under a load of 750g. The hard coating surface was then observed for scratches. The maximum pencil hardness that the hard coating surface could withstand without leaving a scratch was measured.

[0108] Evaluation of friction resistance: Steel wool (000#) was used to rub the surface of the hard coating layer back and forth under a load of 500 g, and the number of friction cycles until scratches appeared was recorded.

[0109] Performance evaluation results of hard coating films HC1 and HC2

[0110]

[0111] As can be seen from the table above, the hard coating films HC1 and HC2 provided in the examples of the present application both achieved an adhesion grade of 5B on the PMMA film under the 100-grid test. This indicates that after the hard coating films HC1 and HC2 provided in the examples of the present application were formed on the PMMA film, no obvious coating shedding occurred under the 100-grid test, indicating that the hard coating films HC1 and HC2 provided in the examples of the present application had excellent adhesion to the PMMA film.

[0112] At the same time, the pencil hardness (750g) of the hard coating films HC1 and HC2 is ≥4H, and the friction resistance test (500g) is ≥20 cycles, indicating that the coating of the hard coating films HC1 and HC2 can give the PMMA film surface strong hardness and wear resistance.

[0113] The coating film and display panel provided in the embodiments of the present application are described in detail above. The description of the above embodiments is only used to help understand the method and core concept of the present application, and should not be understood as limiting the scope of protection of the present application.

Claims

1. A coating film, characterized in that include: The first sub-coating film includes a tetrafunctional polyurethane acrylate oligomer, and the tetrafunctional polyurethane acrylate oligomer includes the following structure: ； as well as The second sub-coating film is arranged on the surface of the first sub-coating film, and the second sub-coating film includes a polyurethane acrylate oligomer with a functionality greater than or equal to six.

2. The coating film according to claim 1, characterized in that The coating film also includes nano-silicon dioxide particles.

3. The coating film according to claim 2, characterized in that The nano-silica particles include nano-silica particles modified with isocyanoethyl acrylate.

4. The coating film according to claim 2, characterized in that The particle size of the nano-silicon dioxide particles is 10 to 1000 nanometers.

5. The coating film according to claim 2, characterized in that The coating film further includes a first photoinitiator; Wherein, the coating film comprises 80 to 120 parts by weight of the tetrafunctional polyurethane acrylate oligomer; 1 to 10 parts by weight of the nano-silica particles; and 1 to 10 parts by weight of the first photoinitiator.

6. The coating film according to claim 1, characterized in that The second sub-coating film includes a ten-functionality polyurethane acrylate oligomer, and the ten-functionality polyurethane acrylate oligomer includes a structure as shown below: 。 7. The coating film according to claim 1, characterized in that The second sub-coating film further comprises an acrylate monomer having a functionality greater than or equal to three and a second photoinitiator; Wherein, the second sub-coating film comprises 80 to 120 parts by weight of the polyurethane acrylate oligomer having a functionality greater than or equal to six; 10 to 30 parts by weight of the acrylate monomer having a functionality greater than or equal to three; and 1 to 10 parts by weight of the second photoinitiator.

8. The coating film according to any one of claims 1 to 7, characterized in that The thickness of the first sub-coating film is 10-1000 nanometers, and the thickness of the second sub-coating film is 1-10 micrometers.

9. A display panel, characterized in that: include: Panel body; a polymethyl methacrylate film, the polymethyl methacrylate film being disposed on a surface of the panel body; as well as The coating film according to any one of claims 1 to 8, wherein the coating film is provided on a surface of the polymethyl methacrylate film away from the panel body.

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