Preparation method of high-transmittance and high-fog coating with microstructure on surface

Abstract

The invention relates to the technical field of optical films, and discloses a preparation method of a high-transmittance and high-fog coating with a microstructure on the surface, and the preparation method comprises the following steps: uniformly mixing a low-surface-energy initiator, a monofunctional acrylate monomer, a polyfunctional acrylate monomer, an acrylate prepolymer and a micromolecular initiator in an organic solvent to obtain light-cured glue; coating the light-cured glue on the surface of a light-transmitting base material, and drying to obtain a coated wet film; and the coating wet film is subjected to ultraviolet irradiation curing, and the high-transmittance and high-fog coating with the microstructure on the surface is obtained. The preparation method has the advantages that the raw materials are simple and easy to obtain, the composition is uniform, processing is convenient, and the equipment requirement is low, the prepared surface wrinkle coating film has high transmittance, high haze and good uniformity, and the surface wrinkle morphology and roughness can be controlled through processing process parameters such as heating time and illumination time.

Description

Technical Field

[0001] This application relates to the field of optical film technology, specifically to a method for preparing a high-transparency, high-haze coating with a microstructure on its surface. Background Technology

[0002] High-transmittance, high-haze films are a type of optical film with extremely high optical transmittance and haze. These films have a strong ability to diffuse light and are commonly used as diffusion films inside liquid crystal displays (LCDs), forming a crucial component of LCDs. When a dot-shaped or strip-shaped backlight passes through the diffusion film, the uniform scattering of light by the film creates a uniform surface light source. Furthermore, due to their light-diffusing effect, high-transmittance, high-haze films are also widely used in lamp shade manufacturing, frosted glass partitions, packaging printing, and other fields.

[0003] High-transmittance, high-haze films typically consist of a high-transmittance substrate and a surface coating with a rough microstructure. The high-transmittance substrate is usually made of polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), or polycarbonate (PC), which have very high optical transmittance. The preparation of the surface coating with a rough microstructure mainly involves methods such as particle coating with photocuring, imprinting with photocuring, and solvent drying. These methods increase the haze of the film surface by constructing a rough structure. For example, patent application CN116774323A prepares a high-haze anti-glare film by coating an anti-glare layer onto a substrate, wherein the coating liquid for the anti-glare layer includes acrylic resin oligomers and anti-glare particles, and then photocuring it. Patent application CN115963584A discloses a high-haze anti-glare film comprising a transparent substrate and an anti-glare coating formed on the transparent substrate. The anti-glare coating includes an acrylic binder resin, multiple amorphous silica particles, and multiple spherical organic microparticles, which are obtained by photocuring the anti-glare coating liquid.

[0004] However, the above methods generally suffer from the following problems: The particle coating method requires mixing insoluble particles during the adhesive preparation process. This causes the insoluble phase in the adhesive to agglomerate or precipitate without stress, affecting the uniformity of the adhesive and the coating film. Furthermore, as the particle content in the adhesive increases, the particle agglomeration problem in the mixture becomes more difficult to solve, which will significantly affect the uniformity of the coating film. Additionally, since only ordinary photoinitiators are used in the UV-curing adhesive, surface oxygen inhibition occurs in the air after coating, resulting in a lower degree of surface curing of the film, exhibiting a "not surface-dried" condition that affects its use. Another type of embossing UV-curing method requires the wet film to directly contact the template before UV curing, placing higher demands on the template and other production equipment. Summary of the Invention

[0005] This application provides a method for preparing a high-transparency, high-haze coating with a microstructure on the surface, aiming to solve the technical problems of oxygen inhibition on the coating surface, non-uniformity of the coating surface caused by particle doping, and complex photocuring equipment in the prior art.

[0006] To achieve the above objectives, the present application adopts the following technical solution.

[0007] A first aspect of this application provides a method for preparing a high-transparency, high-haze coating with a microstructure on its surface, comprising: S1, mix low surface energy initiator, monofunctional acrylate monomer, polyfunctional acrylate monomer, acrylate prepolymer and small molecule initiator evenly in organic solvent to obtain photocurable adhesive; S2, the light-curing adhesive is applied to the surface of a translucent substrate and dried to obtain a coated wet film; S3, the coated wet film is cured by ultraviolet light irradiation to obtain a high-transmittance, high-haze coating with a microstructure on the surface.

[0008] Preferably, the low surface energy initiator is a photoinitiator that can initiate the reaction of the acrylate monomer in the 254~420 nm wavelength range, and its molecular weight is >1000 g / mol.

[0009] More preferably, the low surface energy initiator comprises any one of the following compounds:

[0010]

[0011]

[0012] Where x, y, z, and w represent the percentage of each constituent unit in the total number of units in the macromolecular compound, 0≤x≤60, 5≤y≤50, 10≤z≤50, and 0≤w≤50; “co” indicates that the connection order of each constituent unit is random and disordered.

[0013] Preferably, the monofunctional acrylate monomer is a compound containing one acrylate or methacrylate group; The multifunctional acrylate monomer is a compound containing two or more acrylate or methacrylate groups; The small molecule initiator is a compound with a benzoyl group structure, which can initiate reactions in the 254~420 nm wavelength range.

[0014] More preferably, the monofunctional acrylate monomer includes any one of isobornyl acrylate IBOA, acrylmorpholine ACMO, methyl methacrylate, or butyl methacrylate. The multifunctional acrylate monomers include any one of glycerol trihydroxypropyl ether triacrylate (GPTA), trimethylolpropane triacrylate (TMPTA), 1,6-hexanediol diacrylate (HDDA), hexanediol diacrylate, or trimethylolpropane triacrylate. The small molecule initiator includes photoinitiator DecBP, photoinitiator TPO, or photoinitiator BPAOH; wherein the chemical structure of photoinitiator BPAOH is shown below:

[0015] The acrylate prepolymer is polybutadiene acrylate (PBMA).

[0016] Preferably, the solvent includes at least one selected from ethyl acetate, butyl acetate, dichloromethane, chloroform, acetone, 2-butanone, tetrahydrofuran, ethylene glycol butyl ether, toluene, anisole, or propylene glycol methyl ether acetate. The light-transmitting substrate is any one of polyethylene terephthalate, polymethyl methacrylate, polycarbonate, or glass.

[0017] Preferably, the photocurable adhesive comprises, by weight, 3.5-20 wt% low surface energy initiator, 5-75 wt% monofunctional acrylate monomer, 10-60 wt% polyfunctional acrylate monomer, 0-45 wt% acrylate prepolymer, 0-10 wt% small molecule initiator, and 0-80 wt% solvent.

[0018] More preferably, the solid content of the light-curing adhesive is 20~100 wt%.

[0019] Preferably, the coating method includes any one of blade coating, spin coating, dip coating, or spray coating; The thickness of the coated wet film is 2~200 μm; The drying temperature is 40~100 °C, and the drying time is 5~30 min.

[0020] Preferably, the ultraviolet irradiation curing uses ultraviolet light with a wavelength of 365 nm and an exposure power of 5~1000 mW / cm². 2 The exposure time is 5~180 s.

[0021] Compared with the prior art, the beneficial effects of this application are as follows: This application utilizes a photocurable surface self-wrinkling method to prepare a high-transmittance, high-haze film. The adhesive containing a low-surface-energy photoinitiator exhibits a stable, homogeneous phase after mixing. After being coated onto a substrate surface, the initiator gradients and aggregates towards the air surface of the coating during heat treatment. Subsequently, during photocuring, the coating surface polymerizes and shrinks, creating micro-wrinkle patterns. Simultaneously, the formation of dense surface aggregates effectively resists oxygen inhibition during photocuring, allowing the heat-treated coating to be fully cured in air using a common ultraviolet light source. This application employs a combination of monofunctional and polyfunctional acrylate monomers, resulting in improved mechanical strength and facilitating the formation of micro- and nano-wrinkle patterns. The surface-wrinkled coating prepared in this application exhibits high transmittance, high haze, and good uniformity. Furthermore, the surface wrinkle morphology and roughness can be controlled through processing parameters such as heating time and light exposure time.

[0022] Compared with conventional methods such as particle coating and embossing, this application has the advantages of simple and readily available raw materials, uniform composition, convenient processing, and low equipment requirements: ① The introduction of low surface energy photoinitiators enables the generation of surface microstructures and simplifies the process; ② The coating process is highly compatible with existing industrial film-making processes and is suitable for coating methods such as blade coating, spin coating, dip coating, and spray coating; ③ The photocuring equipment is simple, requiring only a common ultraviolet light source, and the coating can be cured in the air; ④ The raw materials have all been industrially produced and are widely available. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 The molecular structure and proton NMR spectrum of low surface energy macromolecular photoinitiator compound 1 are shown. Figure 2 The molecular structure and proton NMR spectrum of photoinitiator A2959 are shown. Figure 3 The molecular structure and 1H NMR spectrum of compound 2, a low surface energy macromolecular photoinitiator; Figure 4 The molecular structure and proton NMR spectrum of the polymerizable photoinitiated monomer StBP; Figure 5 The molecular structure and proton NMR spectrum of low surface energy macromolecular photoinitiator compound 3 are shown. Figure 6 The molecular structure and 1H NMR spectrum of the small molecule photoinitiator BPAOH; Figure 7 The surface morphology of the high-transparency, high-haze surface coating in Example 5; Figure 8 The surface morphology of the high-transparency, high-haze surface coating in Example 6; Figure 9 The surface morphology of the high-transparency, high-haze surface coating in Example 7; Figure 10 The graph shows the relationship between coating haze and transmittance as a function of UV exposure time. Figure 11 This is a photograph showing the changes in coating haze and transmittance over UV exposure time. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] In the following description of this embodiment, the terms "including", "comprising", "having", and "containing" are all open-ended terms, meaning that they include but are not limited to.

[0027] In the following description of this embodiment, the term "and / or" is used to describe the association relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, B existing alone, and A and B existing simultaneously. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0028] In the following description of this embodiment, the term "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0029] The terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0030] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0031] Those skilled in the art will understand that the numerical ranges in the embodiments of this application should be understood as each intermediate value between the upper and lower limits of the specifically disclosed range. Each smaller range between any stated value or intermediate value within a stated range, and any other stated value or intermediate value within said range, is also included in this application. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0032] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. While this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this application. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0033] In a first aspect, this application provides a method for preparing a high-transparency, high-haze coating with a microstructured surface. This method is based on photocurable self-wrinkling technology. The high-transparency, high-haze coating is obtained by applying a photocurable coating to the surface of a substrate, followed by heat treatment and ultraviolet exposure. The preparation method specifically includes:

[0034] S1, mix low surface energy initiator, monofunctional acrylate monomer, polyfunctional acrylate monomer, acrylate prepolymer and small molecule initiator evenly in organic solvent to obtain photocurable adhesive; In this application, the low surface energy initiator is a photoinitiator capable of initiating the reaction of the acrylate monomer in the 254-420 nm wavelength range, with a molecular weight >1000 g / mol. For example, the low surface energy initiator includes any one of the following compounds:

[0035]

[0036]

[0037]

[0038] Wherein, "x, y, z, w" represent the percentage of each constituent unit in the total number of units in the macromolecular compound, 0≤x≤60, 5≤y≤50, 10≤z≤50, 0≤w≤50; "co" indicates that the connection order of each constituent unit is random and disordered, rather than a certain chemical group.

[0039] In this application, the monofunctional acrylate monomer is a compound containing one acrylate or methacrylate group, preferably any one of isobornyl acrylate (IBOA), acrylmorpholine (ACMO), methyl methacrylate or butyl methacrylate; The multifunctional acrylate monomer is a compound containing two or more acrylate or methacrylate groups; preferably, it is any one of glycerol trihydroxypropyl ether triacrylate (GPTA), trimethylolpropane triacrylate (TMPTA), 1,6-hexanediol diacrylate (HDDA), hexanediol diacrylate, or trimethylolpropane triacrylate. Because multifunctional acrylates have more polymerizable acrylate groups, they exhibit greater cross-linking during polymerization, resulting in better mechanical strength of the prepared coating. Simultaneously, multifunctional acrylates have a higher polymerization shrinkage rate, and their high proportion facilitates the formation of micro / nano wrinkled patterns on the surface. However, due to the extremely rapid curing of the coating during polymerization of multifunctional acrylate monomers, the remaining acrylate units may not react completely, leading to a noticeably hard and brittle coating with poor mechanical properties. Therefore, this application employs a combination of monofunctional and multifunctional acrylate monomers to achieve better results.

[0040] The small molecule initiator is a compound with a benzoyl group structure, which can initiate reactions in the 254-420 nm wavelength range. The preferred small molecule initiator is 4-decylbenzophenone (DecBP), photoinitiator TPO, or photoinitiator BPAOH; wherein the chemical structure of photoinitiator BPAOH is as follows:

[0041]

[0042] The acrylate prepolymer is polybutadiene acrylate (PBMA).

[0043] In this application, the solvent includes at least one of ethyl acetate, butyl acetate, dichloromethane, chloroform, acetone, 2-butanone, tetrahydrofuran, ethylene glycol butyl ether, toluene, anisole, or propylene glycol methyl ether acetate.

[0044] In this application, the UV-curable adhesive comprises, by weight, 3.5-20 wt% low surface energy initiator, 5-75 wt% monofunctional acrylate monomer, 10-60 wt% polyfunctional acrylate monomer, 0-45 wt% acrylate prepolymer, 0-10 wt% small molecule initiator, and 0-80 wt% solvent. The solid content of the UV-curable adhesive is 20-100 wt%.

[0045] S2, the light-curing adhesive is applied to the surface of a translucent substrate and dried to obtain a coated wet film; In this application, the light-transmitting substrate is any one of polyethylene terephthalate, polymethyl methacrylate, polycarbonate, or glass.

[0046] In this application, the coating method includes any one of blade coating, spin coating, dip coating, or spray coating. When blade coating is used, the equipment can be a wire bar, a slit doctor blade (SZQ preparation device), etc.; for small-area blade coating of wet film, a slit doctor blade is preferred; for large-area blade coating, wire bar coating is preferred. The blade coating speed is 10~100 mm / s, and the blade coating speed is determined by controlling the travel speed of the wire bar or slit with a motor. In this application, the blade coating speed is preferably 20 mm / s. When spin coating is used, the spin coating speed is 100~5000 rpm, preferably 1000 rpm.

[0047] In this application, the thickness of the wet coating film is 2~200 μm; the thickness of the wet coating film can be controlled by adjusting factors such as the solvent content of the UV-curable adhesive, spin coating speed, spraying time, gap thickness of the squeegee, spraying time, and viscosity of the dip coating solution.

[0048] In this application, the drying process can be carried out using an oven or an open-type heated table. The drying temperature is 40~100 °C, and the drying time is 5~30 min; preferably, the drying temperature is 60 °C, and the drying time is 10 min.

[0049] S3, the coated wet film is cured by ultraviolet light irradiation to obtain a high-transmittance, high-haze coating with a microstructure on the surface.

[0050] In this application, preferably, the ultraviolet irradiation curing uses ultraviolet light with a wavelength of 365 nm and an exposure power of 5~1000 mW / cm². 2 The exposure time is 5~180 s.

[0051] Ultraviolet (UV) irradiation curing can be performed in an air environment or an inert gas environment, such as a nitrogen atmosphere. UV irradiation curing uses direct UV exposure, and the exposure equipment can be any one or more point, line, or surface light sources containing 365 nm UV light, such as mercury lamps or UV LED lamps, with UV LED lamps being preferred. During exposure, the film can be heated using methods such as a bottom-heated stage, a heat radiation tube, or hot air purging.

[0052] This application utilizes the surface migration-induced wrinkling properties of low surface energy initiators to solve the problem that conventional high-transparency and high-haze coatings require particle doping and template printing for curing, and proposes a novel method for preparing high-transparency and high-haze coatings.

[0053] This application utilizes a photocurable surface self-wrinkling method to prepare a high-transmittance, high-haze film. The adhesive containing a low-surface-energy photoinitiator exhibits a stable, homogeneous phase after mixing. After being coated onto a substrate surface, the initiator gradient-aggregates towards the air surface of the coating during heat treatment. Subsequently, during photocuring, the coating surface polymerizes and shrinks, creating a micro-wrinkled pattern. Simultaneously, the formation of dense surface aggregates effectively resists oxygen inhibition during photocuring, allowing the heat-treated coating to be fully cured in air using a common ultraviolet light source. The surface-wrinkled coating prepared in this application exhibits high transmittance, high haze, and excellent uniformity.

[0054] Compared with conventional methods such as particle coating and embossing, this application has the advantages of simple and readily available raw materials, uniform composition, convenient processing, and low equipment requirements: ① The introduction of low surface energy photoinitiators enables the generation of surface microstructures and simplifies the process; ② The coating process is highly compatible with existing industrial film-making processes and is suitable for coating methods such as blade coating, spin coating, dip coating, and spray coating; ③ The photocuring equipment is simple, requiring only a common ultraviolet light source, and the coating can be cured in the air; ④ The raw materials have all been industrially produced and are widely available.

[0055] The present application will be further illustrated by the following examples.

[0056] For ease of description, some compounds are abbreviated in the examples. The specific correspondences are as follows: IBOA (Isoborneol Acrylate) BPOH 4-Hydroxybenzophenone ACMO Acryloylmorpholine GPTA (glyceryl trihydroxypropyl ether triacrylate) TMPTA trimethylolpropane triacrylate HDDA 1,6-hexanediol diacrylate DecBP 4-decylbenzophenone PBMA (Polybutadiene acrylate) CFA 1H,1H,2H,2H,-Perfluorodecyl acrylate monomer DMAEMA 2-(dimethylamino)methacrylate ABP 4-Acryloyloxybenzophenone AIBN (Azobisisobutyronitrile) StMCl 4-chloromethylstyrene Photoinitiator 2959 2-Hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]-1-propanone BPBr 4-bromomethylbenzophenone TPO diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide THF Tetrahydrofuran DCM dichloromethane Example 1 This embodiment provides a method for preparing a low surface energy initiator. The low surface energy initiator is designated as compound 1, and its molecular structure is shown below, where x : y : z : w = 25 : 15 : 20 : 40.

[0057]

[0058] Its preparation methods include: Monomers IBOA (25 mmol), CFA (15 mmol), DMAEMA (35 mmol), ABP (25 mmol), and thermal initiator AIBN (2 mmol) were added sequentially to a 250 mL single-necked round-bottom flask. Then, dioxane (twice the total mass of the monomers) was added to dissolve all monomers. The flask was protected with nitrogen and heated in a 70 °C oil bath for 12 h. After the reaction, the solution was poured into n-hexane for precipitation. The precipitate was then dissolved in ethyl acetate and precipitated twice more with n-hexane. The resulting solid was dried in a 60 °C vacuum oven for 12 h to obtain low surface energy macromolecular photoinitiator compound 1. Its molecular structure and 1H NMR spectrum are shown below. Figure 1 As shown.

[0059] Example 2 This embodiment provides a method for preparing a low surface energy initiator. The low surface energy initiator is designated as compound 2, and its molecular structure is shown below, where x : y : z = 50 : 20 : 30.

[0060]

[0061] Photoinitiator 2959 (60 mmol) and AOI (60 mmol) were added sequentially to a 250 mL single-necked round-bottom flask, followed by 125 mL of acetonitrile. After stirring briefly, 3 drops of DBTL were added as a catalyst. The flask was then connected to a condenser and heated in a 40 °C oil bath with stirring for 24 h. After the reaction was complete, all solvents were removed using a rotary evaporator. The remaining oily liquid was dried under vacuum at 35 °C for 6 h, and cooled to obtain a white solid product, denoted as photoinitiator A2959. Its chemical structure is shown below, and its 1H NMR spectrum is shown below. Figure 2 As shown.

[0062]

[0063] Add monomers IBOA (30 mmol), PFA (12 mmol), photoinitiator A2959 (18 mmol), and thermal initiator AIBN (1.2 mmol) to a 250 mL flask. Add dioxane (twice the total mass of the monomers) to dissolve all monomers. Protect the flask with nitrogen and heat in a 70 °C oil bath for 12 h. After the reaction, pour the solution into n-hexane to precipitate. Dissolve the precipitate in ethyl acetate and precipitate again in n-hexane twice. Dry the resulting solid in a 60 °C vacuum oven for 12 h to obtain low surface energy macromolecular photoinitiator compound 2. Its molecular structure and 1H NMR spectrum are shown below. Figure 3 As shown.

[0064] Example 3 This embodiment provides a method for preparing a low surface energy initiator. The low surface energy initiator is designated as compound 3, and its molecular structure is shown below, where x : y : z : w = 25 : 15 : 25 : 35.

[0065]

[0066] Add BPOH (104 mmol) to a 500 mL single-necked round-bottom flask and dissolve it in 200 mL DMF. Then add StMCl (80 mmol), KOH (104 mmol), and a catalytic amount of KI. Connect the flask to a condenser and heat to 50 °C for 12 h. After the reaction is complete, dilute the reaction solution with about 150 mL DCM, then wash several times with 5% KOH solution. Collect the lower organic phase and dry it with anhydrous sodium sulfate. Transfer the organic phase to a 1 L round-bottom flask, add twice the volume of n-hexane to dilute it, heat uniformly to 50 °C until it becomes clear, and then concentrate it under reduced pressure using a rotary evaporator until the precipitated solid can no longer dissolve. Stop the rotary evaporation, remove the flask and place it in a -20 °C freezer. After 2 h, a large number of crystals appear. The solid was filtered to obtain a plate-like crystalline product, which was then dried in a 60 °C oven for 12 h to obtain a large quantity of plate-like crystalline product, which can then be used to polymerize the photoinitiating monomer StBP. Its chemical structure is shown below, and its 1H NMR spectrum is shown below. Figure 4 As shown:

[0067]

[0068] Monomers IBOA (25 mmol), CFA (15 mmol), DMAEMA (35 mmol), StBP (25 mmol), and thermal initiator AIBN (2 mmol) were added sequentially to a 250 mL single-necked round-bottom flask. Then, dioxane (twice the total mass of the monomers) was added to dissolve all monomers. The flask was then protected with nitrogen and heated in a 70 °C oil bath for 12 h. After the reaction, the solution was poured into n-hexane to precipitate the solid. The precipitate was dissolved twice more in ethyl acetate and precipitated again in n-hexane. The resulting solid was dried in a 60 °C vacuum oven for 12 h to obtain low surface energy macromolecular photoinitiator compound 3. Its molecular structure and 1H NMR spectrum are shown below. Figure 5 As shown.

[0069] Example 4 This embodiment provides a method for preparing the small molecule initiator BPAOH, whose chemical structure is as follows:

[0070] Its preparation methods include: In a 250 mL single-necked round-bottom flask, BPBr (50 mmol), 2-methylaminoethanol (100 mmol), and potassium carbonate (100 mmol) were added sequentially. After adding 120 mL of THF, the flask was placed in a 60 °C oil bath and stirred for 12 h. After the reaction was complete, the reaction system was washed with dichloromethane-water. The organic phase was dried over anhydrous sodium sulfate, and the organic solvent was then evaporated to obtain a pale yellow liquid product, BPAOH. Its molecular structure and 1H NMR spectrum are shown below. Figure 6 As shown.

[0071] Example 5 This embodiment provides a method for preparing a high-transparency, high-haze coating, including: Mix 50 parts IBOA, 150 parts GPTA, 20 parts low surface energy photoinitiator compound 1, 5 parts small molecule photoinitiator DecBP, 40 parts PBMA and 265 parts ethyl acetate solvent using magnetic stirring for 30 min to obtain a photocurable adhesive. Using a 25 μm wire rod, the above-mentioned UV-curable adhesive was applied to a 150 μm thick PET film at a speed of 15 mm / s, and then placed in a 70 °C oven for 10 min. The film was then treated with 300 mW / cm² adhesive. 2 A high-transmittance, high-haze coating is obtained by irradiating the product with high-power ultraviolet light for 180 seconds.

[0072] Example 6 This embodiment provides a method for preparing a high-transparency, high-haze coating, including: Take 140 parts of IBOA, 50 parts of GPTA, 10 parts of low surface energy macromolecular photoinitiator compound, and 2 parts of small molecule photoinitiator BPAOH, and mix them evenly using magnetic stirring to obtain a light-curing adhesive. The aforementioned UV-curable adhesive was evenly applied to a 150 μm thick PET substrate using a wire rod, and then the film was placed in a 70 °C forced-air oven for 10 min; the film was then treated with 300 mW / cm... 2 When exposed to high-power ultraviolet light for 20 seconds, the wet film on the surface is cured by ultraviolet light and a surface microstructure is generated, resulting in a high-transparency and high-haze coating.

[0073] Example 7 This embodiment provides a method for preparing a high-transparency, high-haze coating, including: 50 parts IBOA, 150 parts GPTA, 20 parts low surface energy photoinitiator compound, 3 and 5 parts small molecule photoinitiator BPAOH, 20 parts prepolymer PBMA and 200 parts ethyl acetate were mixed evenly using magnetic stirring to obtain a photocurable adhesive. The aforementioned UV-curable adhesive was evenly applied to a 150 μm thick PET substrate using a wire rod, and then the film was placed in a 70 °C forced-air oven for 10 min; the film was then treated with 500 mW / cm 2 Irradiation with a high-power UV lamp box for 120 seconds allows the surface wet film to generate surface microstructures while being cured by UV light, resulting in a high-transparency, high-haze coating.

[0074] Example 8 This embodiment provides a method for preparing a high-transparency, high-haze coating, including: 50 parts ACMO, 150 parts TMPTA, 20 parts low surface energy photoinitiator compound 1, 5 parts small molecule photoinitiator DecBP, 40 parts prepolymer PBMA and 200 parts ethyl acetate were mixed evenly using magnetic stirring to obtain a photocurable adhesive. The aforementioned UV-curable adhesive was uniformly spin-coated onto the glass slide substrate at a speed of 3000 rpm. The glass slide was then placed in a 70 °C forced-air oven and baked for 10 min. Finally, the glass slide was treated with a 600 mW / cm² adhesive. 2 Irradiation with a high-power UV lamp box for 180 seconds allows the wet film on the surface to generate surface microstructures while being cured by UV light, resulting in a high-transparency, high-haze surface coating.

[0075] Example 9 This embodiment provides a method for preparing a high-transparency, high-haze coating, including: 100 parts IBOA, 100 parts GPTA, 20 parts low surface energy photoinitiator compound, 3 and 5 parts small molecule photoinitiator DecBP, 40 parts prepolymer PBMA and 200 parts ethyl acetate were mixed evenly using magnetic stirring to obtain a photocurable adhesive. The aforementioned UV-curable adhesive was uniformly spin-coated onto the glass slide substrate at a speed of 1000 rpm. The glass slide was then placed in a 70 °C forced-air oven and baked for 10 min. Finally, the glass slide was treated with a 600 mW / cm² adhesive. 2 Irradiation with a high-power UV lamp box for 120 seconds allows the wet film on the surface to generate surface microstructures while being cured by UV light, resulting in a high-transparency, high-haze surface coating.

[0076] Example 10 The difference between Example 10 and Example 9 is that the spin coating speed is 3000 rpm, while the rest are the same as in Example 9.

[0077] Example 11 Take 100 parts IBOA, 100 parts HDDA, 20 parts low surface energy macromolecular photoinitiator compound, and 2 and 3 parts small molecule photoinitiator BPAOH and mix them evenly with magnetic stirring to obtain a light-curing adhesive; The aforementioned UV-curable adhesive was uniformly coated onto a 150 μm thick PET substrate using a 100 μm wire rod. The film was then baked in a 70 °C oven for 10 min to obtain the coating. Finally, the film was treated with 300 mW / cm... 2 Irradiation with a high-power UV lamp box for 30 seconds allows the wet film on the surface to generate surface microstructures while being cured by UV light, resulting in a high-transparency, high-haze surface coating.

[0078] Example 12 100 parts IBOA, 100 parts GPTA, 20 parts low surface energy photoinitiator compound, 3 and 5 parts small molecule photoinitiator DecBP, 40 parts prepolymer PBMA and 200 parts ethyl acetate were mixed evenly using magnetic stirring to obtain a photocurable adhesive. The aforementioned UV-curable adhesive was uniformly spin-coated onto the glass slide substrate at a speed of 5000 rpm. The glass slide was then placed in a 70 °C forced-air oven and baked for 10 min. Finally, the glass slide was treated with a 600 mW / cm² adhesive. 2 Irradiation with a high-power UV lamp box for 120 seconds allows the wet film on the surface to generate surface microstructures while being cured by UV light, resulting in a high-transparency, high-haze surface coating.

[0079] Example 13 Take 150 parts of IBOA, 50 parts of TMPTA, 10 parts of low surface energy macromolecular photoinitiator compound, and 2 and 3 parts of small molecule photoinitiator BPAOH and mix them evenly with magnetic stirring to obtain a light-curing adhesive. The aforementioned UV-curable adhesive was uniformly coated onto a 150 μm thick PET substrate using a 100 μm wire rod. The film was then baked in a 70 °C oven for 10 min to obtain the coating. Finally, the film was treated with 300 mW / cm... 2 Irradiation with a high-power UV lamp box for 30 seconds allows the wet film on the surface to generate surface microstructures while being cured by UV light, resulting in a high-transparency, high-haze surface coating.

[0080] The morphology of the high-transparency, high-haze surface coatings prepared in Examples 5-13 was evaluated as follows: Figure 7 The surface morphology of the high-transparency, high-haze surface coating in Example 5 was obtained by three-dimensional scanning imaging using a laser scanning confocal microscope. The image size is 256 μm × 256 μm. Figure 7 It can be seen that a microstructure coating with a height difference has been formed on the surface of the thin film.

[0081] Figure 8 The surface morphology of the high-transparency, high-haze surface coating in Example 6 was obtained by three-dimensional scanning imaging using a laser scanning confocal microscope. The image size is 256 μm × 256 μm. Figure 8 It can be seen that a microstructure coating with a height difference has been formed on the surface of the thin film.

[0082] Figure 9 The surface morphology of the high-transparency, high-haze surface coating in Example 7 was obtained by three-dimensional scanning imaging using a laser scanning confocal microscope. The image size is 256 μm × 256 μm. Figure 9 It can be seen that a microstructure coating with a height difference has been formed on the surface of the thin film.

[0083] Example 5 describes the preparation of a high-transmittance, high-haze surface coating. During UV irradiation, the changes in haze and transmittance of the coating (including the PET substrate) with UV exposure time were tested. Irradiation was stopped within the indicated time, allowing the haze to remain at the corresponding value. Specific data are shown in Table 1 and... Figure 10 As shown.

[0084] Table 1. Test results showing the relationship between coating haze and transmittance and UV exposure time.

[0085] From Table 1 and Figure 10 It can be seen that the transmittance of the coating remains basically unchanged, while the haze increases with the increase of UV exposure time, and its photographic effect is as follows. Figure 11 As shown.

[0086] The transmittance and haze test results of the high-transmittance and high-haze surface coatings in Examples 5-13 are shown in Table 2.

[0087] Table 2. Transmittance and haze test results of high-transmittance and high-haze surface coatings

[0088] As shown in Tables 1 and 2, the surface wrinkled coating prepared in this application exhibits high transmittance, high haze, and good uniformity. Furthermore, the surface wrinkle morphology and roughness can be controlled by process parameters such as heating time and light exposure time. Compared with conventional methods such as particle coating and embossing, this application has the advantages of simple and readily available raw materials, uniform composition, convenient processing, and low equipment requirements.

[0089] Although this application has been described in detail in this specification with general descriptions and specific embodiments, some modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, such modifications or improvements made without departing from the spirit of this application are all within the scope of protection claimed in this application.

Claims

1. A method for preparing a high-transparency, high-haze coating with a microstructure on its surface, characterized in that, include: S1, mix low surface energy initiator, monofunctional acrylate monomer, polyfunctional acrylate monomer, acrylate prepolymer and small molecule initiator evenly in organic solvent to obtain photocurable adhesive; S2, the light-curing adhesive is applied to the surface of a translucent substrate and dried to obtain a coated wet film; S3, the coated wet film is cured by ultraviolet light irradiation to obtain a high-transmittance, high-haze coating with a microstructure on the surface.

2. The preparation method according to claim 1, characterized in that, The low surface energy initiator is a photoinitiator that can initiate the reaction of the acrylate monomer in the 254~420 nm wavelength range, and its molecular weight is >1000 g / mol.

3. The preparation method according to claim 2, characterized in that, The low surface energy initiator includes any one of the following compounds: ； ； ； Where x, y, z, and w represent the percentage of each constituent unit in the total number of units in the macromolecular compound, 0≤x≤60, 5≤y≤50, 10≤z≤50, and 0≤w≤50; "co" indicates that the connection order of each constituent unit is random and disordered.

4. The preparation method according to claim 1, characterized in that, The monofunctional acrylate monomer is a compound containing one acrylate or methacrylate group; The multifunctional acrylate monomer is a compound containing two or more acrylate or methacrylate groups; The small molecule initiator is a compound with a benzoyl group structure, which can initiate reactions in the 254~420 nm wavelength range.

5. The preparation method according to claim 4, characterized in that, The monofunctional acrylate monomer includes any one of isobornyl acrylate IBOA, acrylmorpholine ACMO, methyl methacrylate or butyl methacrylate. The multifunctional acrylate monomers include any one of glycerol trihydroxypropyl ether triacrylate (GPTA), trimethylolpropane triacrylate (TMPTA), 1,6-hexanediol diacrylate (HDDA), hexanediol diacrylate, or trimethylolpropane triacrylate. The small molecule initiator includes photoinitiator DecBP, photoinitiator TPO, or photoinitiator BPAOH; wherein the chemical structure of photoinitiator BPAOH is shown below: ； The acrylate prepolymer is polybutadiene acrylate (PBMA).

6. The preparation method according to claim 1, characterized in that, The solvent includes at least one of ethyl acetate, butyl acetate, dichloromethane, chloroform, acetone, 2-butanone, tetrahydrofuran, ethylene glycol butyl ether, toluene, anisole, or propylene glycol methyl ether acetate. The light-transmitting substrate is any one of polyethylene terephthalate, polymethyl methacrylate, polycarbonate, or glass.

7. The preparation method according to claim 1, characterized in that, The photocurable adhesive, by weight, comprises 3.5-20 wt% low surface energy initiator, 5-75 wt% monofunctional acrylate monomer, 10-60 wt% polyfunctional acrylate monomer, 0-45 wt% acrylate prepolymer, 0-10 wt% small molecule initiator, and 0-80 wt% solvent.

8. The preparation method according to claim 7, characterized in that, The solid content of the light-curing adhesive is 20~100wt%.

9. The preparation method according to claim 1, characterized in that, The coating method includes any one of scraping, spin coating, dip coating, or spray coating; The thickness of the coated wet film is 2~200 μm; The drying temperature is 40~100 °C, and the drying time is 5~30 min.

10. The preparation method according to claim 1, characterized in that, The ultraviolet light curing process uses ultraviolet light with a wavelength of 365 nm and an exposure power of 5~1000 mW / cm². 2 The exposure time is 5~180 s.

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