Nano-zirconia dispersion liquid and preparation method thereof, optical coating liquid, optical film and application thereof

Abstract

The invention discloses a nano-zirconia dispersion liquid and a preparation method thereof, an optical coating liquid, an optical film and application thereof, and relates to the technical field of materials. The nano zirconium oxide dispersion liquid comprises modified nano zirconium oxide and a first organic solvent, and a modifier of the modified nano zirconium oxide comprises a coupling agent and polymer resin; wherein the polymer resin is poly (isobornyl acrylate-co-polyethylene glycol methacrylate). A flexible segment of polyethylene glycol methacrylate in the polymer resin provides better flexibility for the optical film, and a bridge ring structure of isobornyl acrylate forms a net structure with high crosslinking density in a film forming process and reduces internal stress in a photocuring process, so that better hardness performance is provided for the optical film; the nanoscale particle size zirconium oxide significantly improves the dispersion uniformity, reduces light scattering, improves the light transmittance and light transmission uniformity of the optical film, and reduces the haze of the film. And the method is expected to be popularized and applied in the frontier fields of high-precision optical systems, flexible display and the like.

Description

Technical Field

[0001] This invention relates to the field of materials technology, and more specifically, to nano-zirconia dispersions and their preparation methods, optical coatings, optical films and their applications. Background Technology

[0002] Due to its high refractive index, excellent thermal stability and chemical inertness, nano-zirconia has become one of the important candidate materials for preparing high-transmittance optical films. With the rapid development of modern display technology, optical communication and optical instrument industry, the demand for high-performance optical films is increasing day by day.

[0003] Optical films prepared by existing nano-zirconia dispersion systems generally suffer from problems such as insufficient toughness, unsatisfactory hardness, and uneven light transmittance distribution. In addition, research on the performance of optical films is inadequate, and there is a lack of reference data. These problems not only affect the processing durability and service life of optical components, but also limit their application in cutting-edge fields such as high-precision optical systems and flexible displays.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide nano-zirconia dispersions and their preparation methods, optical coatings, optical films and their applications, in order to solve or improve the above-mentioned technical problems.

[0006] This invention is implemented as follows: In a first aspect, the present invention provides a nano-zirconia dispersion, which, by weight, comprises the following components: 23-47 parts of modified nano-zirconia and 40-190 parts of a first organic solvent; the modifier of the modified nano-zirconia comprises 1-3 parts of a coupling agent and 2-4 parts of a polymer resin. The polymer resin is poly(isoborneol acrylate-co-polyethylene glycol methacrylate).

[0007] Secondly, the present invention provides a method for preparing a nano-zirconia dispersion as described in any of the foregoing embodiments, comprising the following steps: The intermediate product was obtained by modifying nano-zirconia with a coupling agent at a temperature of 40℃-70℃ for 2h-8h. The intermediate product is mixed with the polymer resin in a certain proportion and reacted at a temperature of 40℃-60℃ for 2h-5h to obtain modified nano-zirconia.

[0008] Thirdly, the present invention provides an optical coating liquid, comprising, by weight, 40-80 parts of a nano-zirconia dispersion as described in any of the foregoing embodiments or a nano-zirconia dispersion prepared by the preparation method described in any of the foregoing embodiments, 0.5-1.0 parts of a photoinitiator, and 0.5-1.5 parts of a leveling agent.

[0009] Fourthly, the present invention provides an optical film, which is prepared by coating an optical coating liquid as described in any of the foregoing embodiments onto the surface of a substrate and then performing a photocuring treatment. The substrate is selected from at least one of polyethylene terephthalate, polyethylene naphthalate, polymethyl methacrylate, polybutylene terephthalate, polyamide-imide and cellulose triacetate; The optical film has at least one of the following characteristics: flexibility ≤2mm, hardness ≥H, thickness relative range ≤1%, transmittance relative range ≤1%, light transmittance ≥90%, and haze ≤0.5%.

[0010] Fifthly, the present invention provides an application of the optical film as described in the foregoing embodiments in display devices, optical communications, and optical instruments.

[0011] The present invention has the following beneficial effects: In the nano-zirconia dispersion provided in this invention, the flexible segments of polyethylene glycol methacrylate in the polymer resin can provide better flexibility for the optical film, while the bridged ring structure of isoborneol acrylate can form a high cross-linking density network structure during film formation and reduce internal stress during photocuring, thereby providing better hardness performance for the optical film. The addition of nano-sized zirconia particles significantly improves the dispersion uniformity of zirconia while reducing light scattering, thereby improving the transmittance and transmittance uniformity of the optical film and reducing film haze. It is expected to be widely used in cutting-edge fields such as high-precision optical systems and flexible displays. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0013] Chinese patent CN105236962A discloses a method for preparing a nano-zirconia dispersion and an optical enhancement film. It uses a stepwise modification method, employing silane coupling agents, long-chain alkyl acrylic acids, and resin monomers to modify nano-zirconia, and then photocures the resulting optical film. However, the optical film's performance is only qualitatively described as having "high hardness," without quantitative experimental characterization. Chinese patent CN113773691A discloses another method for preparing a nano-zirconia dispersion and an optical film, using organic acids, coupling agents, and metal complexes to modify nano-zirconia, and then photocuring the resulting optical film. However, this method only evaluates the refractive index of the zirconia dispersion without further evaluating the performance of the optical film, making it difficult to obtain specific performance data for the final product and thus less reliable for reference.

[0014] The present invention provides a nano-zirconia dispersion and its preparation method, an optical coating, an optical film, and their applications. Multi-angle performance tests were conducted on the final optical film, revealing that the resulting optical film exhibits excellent flexibility, high hardness, small relative thickness variation, small relative transmittance variation, high light transmittance, and low haze. The relevant implementation methods are as follows: In a first aspect, the present invention provides a nano-zirconia dispersion, which, by weight, comprises the following components: 23-47 parts of modified nano-zirconia and 40-190 parts of a first organic solvent; the modifier of the modified nano-zirconia comprises 1-3 parts of a coupling agent and 2-4 parts of a polymer resin. The polymer resin is poly(isoborneol acrylate-co-polyethylene glycol methacrylate).

[0015] It should be noted that the polymer resin is loaded on the surface of the modified nano-zirconia. The flexible segments of polyethylene glycol in the polymer resin can provide better flexibility for the optical film, while the bridged ring structure of isoborneol can form a network structure with high cross-linking density during film formation and reduce internal stress during photocuring, thereby providing better hardness performance for the optical film.

[0016] In an optional embodiment, the particle size of nano-zirconia is 10nm-30nm; the addition of nano-sized zirconia particles, in combination with polymer resin, helps to significantly improve the dispersion uniformity of zirconia while reducing light scattering, thereby improving the transmittance and transmittance uniformity of the optical film and reducing the haze of the film.

[0017] In an optional embodiment, the polymer resin comprises polyethylene glycol methacrylate and isobornyl acrylate in a weight ratio of 2:3 to 3:1.

[0018] For example, the weight ratio of polyethylene glycol methacrylate to isoborneol acrylate can be selected from any one of 2:3, 1:1, 2:1 and 3:1, or any value between 2:3 and 3:1.

[0019] In an optional embodiment, the modifier of the modified nano-zirconia comprises, by weight, 1-3 parts of coupling agent and 2-4 parts of polymer resin.

[0020] In an optional embodiment, the coupling agent is selected from at least one of silane coupling agents, titanate coupling agents, and aluminate coupling agents; the coupling agent contains at least one of vinyl, allyl, acryloyloxy, amino, alkoxy, and alkyl groups.

[0021] In an optional embodiment, the first organic solvent is selected from at least one of ethanol, acetone, propylene glycol methyl ether, ethylene glycol methyl ether, propylene glycol ethyl ether, methyl isobutyl ketone, and ethylene glycol ethyl ether.

[0022] It should be noted that modified nano-zirconia is prone to stress concentration points and is difficult to disperse uniformly in the matrix. The first organic solvent, as the solvent system of the nano-zirconia dispersion, can ensure the dispersion state of the modified nano-zirconia and prevent it from agglomerating, settling or stratifying during storage, thereby affecting its performance.

[0023] In an optional embodiment, the average molecular weight of polyethylene glycol methacrylate is 300-1000; setting the average molecular weight of polyethylene glycol methacrylate is beneficial to controlling the proportion of flexible segments introduced, thereby regulating the mechanical properties of the final optical film.

[0024] In an optional embodiment, the solid content of the nano-zirconia dispersion is 20%-35%.

[0025] It should be noted that the solid content directly affects the refractive index and light transmittance of the final optical film; an appropriate solid content can also enable the nano-zirconia dispersion to form a stable suspension system, prevent particle sedimentation and stratification, and ensure long-term storage stability.

[0026] In an optional embodiment, the raw materials for preparing the polymer resin include, by weight, 270-430 parts of a second organic solvent and 0.1-0.3 parts of an initiator; The second organic solvent includes 120-180 parts of a third organic solvent, 100-150 parts of a fourth organic solvent, and 50-100 parts of a fifth organic solvent; wherein the third organic solvent is selected from at least one of methanol, ethyl acetate, dimethylacetamide, acetone, and dichloromethane; the fourth organic solvent is selected from at least one of diethyl ether and cyclohexane; and the fifth organic solvent is selected from at least one of ethanol and diethyl ether.

[0027] In an optional embodiment, the initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptanenitrile, and diisopropyl peroxide dicarbonate; the role of the initiator is to provide an active center, and the addition of the initiator is beneficial to control the polymerization rate, initiate the polymerization reaction, and affect the molecular weight of the polymer product.

[0028] Secondly, the present invention provides a method for preparing a nano-zirconia dispersion as described in any of the foregoing embodiments, comprising the following steps: The intermediate product was obtained by modifying nano-zirconia with a coupling agent at a temperature of 40℃-70℃ for 2h-8h. The intermediate product is mixed with the polymer resin in a certain proportion and reacted at a temperature of 40℃-60℃ for 2h-5h to obtain modified nano-zirconia.

[0029] Specifically, the preparation method of the nano-zirconia dispersion includes the following steps: Nano-zirconia (20-40 parts, particle size 10nm-30nm) was added to anhydrous ethanol, ultrasonically dispersed, and then a coupling agent (1-3 parts) was added. The mixture was modified at 40℃-70℃ for 2-8 hours with auxiliary stirring during the process to obtain an intermediate product. After the reaction was completed, the intermediate product was washed by centrifugation with anhydrous ethanol and ultrasonically dispersed in acetone to obtain an intermediate product dispersion.

[0030] Add 2-4 parts of polymer resin to the intermediate product dispersion prepared above, and react at 40℃-60℃ for 2-5 hours with auxiliary stirring during the reaction. After the reaction is completed, wash the product 3-5 times with anhydrous ethanol by centrifugation, and then ultrasonically disperse the obtained solid product in the first organic solvent to obtain a nano-zirconia dispersion with a solid content of 20%-35%.

[0031] Washing is mainly to remove unreacted polymer resin. Theoretically, the more unreacted polymer resin there is, the more times centrifugation and washing are required. The specific number of centrifugation and washing cycles should be adjusted reasonably according to the actual situation. The number of washing cycles is confirmed by combining product performance with the clarity of the supernatant.

[0032] In an optional embodiment, the preparation of the polymer resin includes the following steps: In a protective atmosphere, polyethylene glycol methacrylate, isobornyl acrylate, an initiator, and a third organic solvent are mixed in proportion and reacted at a temperature of 30°C-80°C for 12-20 hours to obtain the first system; wherein the protective gas is selected from at least one of nitrogen, argon, and helium.

[0033] The first system and the fourth organic solvent were centrifuged at 4000 rpm-10000 rpm for 30 min-60 min to obtain the second system. The second system was cleaned with a fifth organic solvent and then dried to obtain a polymer resin.

[0034] In an optional embodiment, after the intermediate product has reacted with the polymer resin, the process further includes: The product system was cleaned with an alcohol solution, and the cleaned solid material was dispersed in a first organic solvent to obtain a nano-zirconia dispersion.

[0035] Specifically, the preparation of polymer resins includes the following steps: In a protective atmosphere, polyethylene glycol methacrylate (40-60 parts, average molecular weight 300-1000), isobornyl acrylate (20-60 parts), and a third organic solvent (120-180 parts) are added to a reaction vessel in proportion. After the substances are completely dissolved, an initiator (0.1-0.3 parts) is added. The reaction is carried out at 30℃-80℃ for 12-20 hours to obtain the first system. The first system and the fourth organic solvent (100-150 parts) were centrifuged at 4000-10000 rpm for 30-60 minutes until precipitation was complete. The precipitate was recovered to obtain the second system. The second system was cleaned 3-5 times with a fifth organic solvent (50-100 parts), and then dried to obtain the polymer resin, namely poly(isoborneol acrylate-co-polyethylene glycol methacrylate). Vacuum drying was used until constant weight was achieved. Washing primarily removed unreacted monomers and initiators; theoretically, the more unreacted monomers present, the more centrifugal washings were required. The number of washing cycles was determined by the product performance and the clarity of the supernatant.

[0036] Thirdly, the present invention provides an optical coating liquid, comprising, by weight, 40-80 parts of a nano-zirconia dispersion as described in any of the foregoing embodiments or a nano-zirconia dispersion prepared by the preparation method described in any of the foregoing embodiments, 0.5-1.0 parts of a photoinitiator, and 0.5-1.5 parts of a leveling agent.

[0037] In an optional embodiment, the photoinitiator is selected from at least one of 1-hydroxycyclohexylphenyl ketone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, methyl benzoylformate, 2,2-dimethoxy-2-phenylacetophenone, and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone.

[0038] In an optional embodiment, the leveling agent is selected from at least one of BYK-301, BYK-333, BYK-332 and BYK-348.

[0039] In an optional embodiment, an optical coating is prepared by uniformly mixing a nano-zirconia dispersion, a photoinitiator, and a leveling agent in a certain proportion.

[0040] Fourthly, the present invention provides an optical film, which is prepared by coating an optical coating liquid as described in any of the foregoing embodiments onto the surface of a substrate and then performing a photocuring treatment; wherein the photocuring treatment is performed using 300 mJ / cm 2 -1000mJ / cm 2 Energy is used for photocuring, and the specific amount can be adjusted as needed.

[0041] The substrate is selected from at least one of polyethylene terephthalate, polyethylene naphthalate, polymethyl methacrylate, polybutylene terephthalate, polyamide-imide and cellulose triacetate; The optical film has at least one of the following characteristics: flexibility ≤2mm, hardness ≥H, thickness relative range ≤1%, transmittance relative range ≤1%, light transmittance ≥90%, and haze ≤0.5%.

[0042] The thickness of the optical coating obtained by the optical coating liquid ranges from 2μm to 10μm, and can be reasonably set according to actual needs.

[0043] Fifthly, the present invention provides an application of the optical film as described in the foregoing embodiments in display devices, optical communications, and optical instruments.

[0044] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0045] It should be noted that the amounts of substances used in the embodiments or comparative examples provided by this invention are all based on parts by weight.

[0046] Example 1 This embodiment provides an optical film, which includes the following steps: (1) Preparation of polymer resin In a nitrogen atmosphere, polyethylene glycol methacrylate (40 parts, average molecular weight 300), isobornyl acrylate (20 parts) and a third organic solvent (120 parts, acetone) were added to a reaction vessel in proportion. After the substances were completely dissolved, an initiator (0.1 parts, azobisisoheptanenitrile) was added, and the reaction was carried out at 50°C for 14 hours to obtain the first system. The first system and the fourth organic solvent (120 parts, cyclohexane) were centrifuged at 8000 rpm for 60 min until precipitation was complete. The precipitate was recovered to obtain the second system. The second system was cleaned three times with a fifth organic solvent (60 parts, anhydrous ethanol), and then dried to obtain the polymer resin, namely poly(isoborneol acrylate-co-polyethylene glycol methacrylate). Vacuum drying was used to achieve constant weight.

[0047] (2) Preparation of nano-zirconia dispersion 20 parts of nano-zirconia (particle size 18.55 nm) were added to anhydrous ethanol (400 parts), ultrasonically dispersed, and then a coupling agent (2 parts, vinyltriethoxysilane) was added. The mixture was modified at 50 °C for 4 h with auxiliary stirring during the process to obtain an intermediate product. After the reaction was completed, the intermediate product was washed three times by centrifugation with anhydrous ethanol. The obtained substance was ultrasonically dispersed in acetone to obtain an intermediate product dispersion with a solid content of 30%. All of the obtained intermediate product dispersion was polymer modified.

[0048] Add the polymer resin (3 parts) obtained in step (1) to the above intermediate product dispersion and react at 50°C for 3 hours. During the reaction, the mixture is stirred and washed three times with anhydrous ethanol. The solid product is ultrasonically dispersed in the first organic solvent (propylene glycol ethyl ether) to obtain a nano-zirconia dispersion with a solid content of 25%.

[0049] It should be noted that the solid content ratio is calculated based on the amount of nano-zirconia, coupling agent, polymer resin added, and the first organic solvent, and there is no need to calculate the ratio between polymer resin and intermediate product separately.

[0050] (3) Preparation of optical film The nano-zirconia dispersion (50 parts), photoinitiator (0.6 parts, 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone), and leveling agent (1.0 parts, BYK-332) prepared in step (2) were mixed evenly in proportion to obtain an optical coating.

[0051] The optical coating solution prepared above was coated onto polyethylene terephthalate, with a coating thickness of 5 μm. The optical film was then obtained after photocuring. The photocuring conditions were 600 mJ / cm² energy.

[0052] Example 2 This embodiment provides an optical film, the preparation steps of which are the same as those in Embodiment 1, the only difference being: (1) Preparation of polymer resin In a nitrogen atmosphere, polyethylene glycol methacrylate (50 parts, average molecular weight 500), isobornyl acrylate (20 parts) and a third organic solvent (140 parts, acetone) were added to a reaction vessel in proportion. After the substances were completely dissolved, an initiator (0.1 parts, azobisisoheptanenitrile) was added, and the reaction was carried out at 50°C for 14 hours to obtain the first system. The first system and the fourth organic solvent (130 parts, cyclohexane) were centrifuged at 8000 rpm for 60 min until precipitation was complete. The precipitate was recovered to obtain the second system. The second system was cleaned three times with a fifth organic solvent (60 parts, anhydrous ethanol), and then dried to obtain the polymer resin, namely poly(isoborneol acrylate-co-polyethylene glycol methacrylate). Vacuum drying was used to achieve constant weight.

[0053] Example 3 This embodiment provides an optical film, the preparation steps of which are the same as those in Embodiment 1, the only difference being: (1) Preparation of polymer resin In a nitrogen atmosphere, polyethylene glycol methacrylate (60 parts, average molecular weight 950), isobornyl acrylate (20 parts) and a third organic solvent (160 parts, acetone) were added to a reaction vessel in proportion. After the substances were completely dissolved, an initiator (0.2 parts, azobisisoheptanenitrile) was added, and the reaction was carried out at 50°C for 18 hours to obtain the first system. The first system and the fourth organic solvent (150 parts, cyclohexane) were centrifuged at 10,000 rpm for 60 min until precipitation was complete. The precipitate was recovered to obtain the second system. The second system was cleaned five times with a fifth organic solvent (100 parts, anhydrous ethanol), and then dried to obtain the polymer resin, namely poly(isoborneol acrylate-co-polyethylene glycol methacrylate). Vacuum drying was used to achieve constant weight.

[0054] Example 4 This embodiment provides an optical film, the preparation steps of which are the same as those in Embodiment 1, the only difference being: (1) Preparation of polymer resin In a nitrogen atmosphere, polyethylene glycol methacrylate (40 parts, average molecular weight 500), isobornyl acrylate (40 parts), and a third organic solvent (180 parts, acetone) were added to a reaction vessel in proportion. After the substances were completely dissolved, an initiator (0.25 parts, diisopropyl peroxide) was added, and the reaction was carried out at 45°C for 20 hours to obtain the first system. The first system and the fourth organic solvent (150 parts, cyclohexane) were centrifuged at 10,000 rpm for 60 min until precipitation was complete. The precipitate was recovered to obtain the second system. The second system was cleaned five times with a fifth organic solvent (100 parts, anhydrous ethanol), and then dried to obtain the polymer resin, namely poly(isoborneol acrylate-co-polyethylene glycol methacrylate). Vacuum drying was used to achieve constant weight.

[0055] (2) Preparation of nano-zirconia dispersion 30 parts of nano-zirconia (particle size 16.66 nm) were added to anhydrous ethanol (500 parts), ultrasonically dispersed, and then a coupling agent (2 parts, vinyltris(2-methoxyethoxy)silane) was added. The mixture was modified at 50 °C for 6 h with auxiliary stirring during the process to obtain an intermediate product. After the reaction was completed, the mixture was washed three times by centrifugation with anhydrous ethanol. The obtained substance was ultrasonically dispersed in acetone to obtain an intermediate product dispersion.

[0056] Add the polymer resin (3 parts) obtained in step (1) to the above intermediate product dispersion and react at 50°C for 6 hours. During the reaction, the mixture is stirred and washed three times with anhydrous ethanol. The solid product is ultrasonically dispersed in the first organic solvent (ethylene glycol ethyl ether) to obtain a nano-zirconia dispersion with a solid content of 25%.

[0057] (3) Preparation of optical film The nano-zirconia dispersion (60 parts) obtained in step (2), photoinitiator (1.0 part, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide) and leveling agent (1.0 part, BYK-332) were mixed evenly in proportion to prepare an optical coating.

[0058] Example 5 This embodiment provides an optical film, the preparation steps of which are the same as those in Embodiment 1, the only difference being: (1) Preparation of polymer resin In a nitrogen atmosphere, polyethylene glycol methacrylate (40 parts, average molecular weight 300), isobornyl acrylate (60 parts) and a third organic solvent (180 parts, acetone) were added to a reaction vessel in proportion. After the substances were completely dissolved, an initiator (0.3 parts, diisopropyl peroxide) was added. The reaction was carried out at 45°C for 20 hours to obtain the first system. The first system and the fourth organic solvent (150 parts, cyclohexane) were centrifuged at 10,000 rpm for 60 min until precipitation was complete. The precipitate was recovered to obtain the second system. The second system was cleaned five times with a fifth organic solvent (100 parts, anhydrous ethanol), and then dried to obtain the polymer resin, namely poly(isoborneol acrylate-co-polyethylene glycol methacrylate). Vacuum drying was used to achieve constant weight.

[0059] Example 6 This embodiment provides an optical film, the preparation steps of which are the same as those in Embodiment 1, the only difference being: (2) Preparation of nano-zirconia dispersion 20 parts of nano-zirconia (particle size 27.24 nm) were added to anhydrous ethanol (400 parts), ultrasonically dispersed, and then a coupling agent (2 parts, vinyltriethoxysilane) was added. The mixture was modified at 50 °C for 4 h with auxiliary stirring during the process to obtain an intermediate product. After the reaction was completed, the intermediate product was washed three times by centrifugation with anhydrous ethanol and ultrasonically dispersed in acetone to obtain an intermediate product dispersion.

[0060] The polymer resin (2 parts) obtained in step 1 was added to the above intermediate product dispersion and reacted at 50°C for 3 hours with auxiliary stirring. After the reaction was completed, the product was washed three times by centrifugation with anhydrous ethanol. The solid product was ultrasonically dispersed in the first organic solvent (propylene glycol ethyl ether) to obtain a nano-zirconia dispersion with a solid content of 25%.

[0061] Example 7 This embodiment provides an optical film, the preparation steps of which are the same as those in Embodiment 1, the only difference being: (2) Preparation of nano-zirconia dispersion 20 parts of nano-zirconia (particle size 12.36 nm) were added to anhydrous ethanol (400 parts), ultrasonically dispersed, and then a coupling agent (2 parts, vinyltriethoxysilane) was added. The mixture was modified at 50 °C for 4 h with auxiliary stirring during the process to obtain an intermediate product. After the reaction was completed, the intermediate product was washed three times by centrifugation with anhydrous ethanol and ultrasonically dispersed in acetone to obtain an intermediate product dispersion.

[0062] The polymer resin (4 parts) obtained in step 1 was added to the above intermediate product dispersion and reacted at 50°C for 3 hours with auxiliary stirring. After the reaction was completed, the product was washed three times by centrifugation with anhydrous ethanol. The solid product was ultrasonically dispersed in the first organic solvent (propylene glycol ethyl ether) to obtain a nano-zirconia dispersion with a solid content of 25%.

[0063] Example 8 This embodiment provides an optical film, the preparation steps of which are the same as those in Embodiment 1, the only difference being: (1) Preparation of polymer resin In a nitrogen atmosphere, polyethylene glycol methacrylate (40 parts, average molecular weight 500), isobornyl acrylate (20 parts) and a third organic solvent (120 parts, acetone) were added to a reaction vessel in proportion. After the substances were completely dissolved, an initiator (0.1 parts, azobisisoheptanenitrile) was added, and the reaction was carried out at 50°C for 14 hours to obtain the first system. The first system and the fourth organic solvent (120 parts, cyclohexane) were centrifuged at 8000 rpm for 60 min until precipitation was complete. The precipitate was recovered to obtain the second system. The second system was cleaned three times with a fifth organic solvent (60 parts, anhydrous ethanol), and then dried to obtain the polymer resin, namely poly(isoborneol acrylate-co-polyethylene glycol methacrylate). Vacuum drying was used to achieve constant weight.

[0064] Example 9 This embodiment provides an optical film, the preparation steps of which are the same as those in Embodiment 1, the only difference being: (1) Preparation of polymer resin In a nitrogen atmosphere, polyethylene glycol methacrylate (40 parts, average molecular weight 950), isobornyl acrylate (20 parts) and a third organic solvent (120 parts, acetone) were added to a reaction vessel in proportion. After the substances were completely dissolved, an initiator (0.1 parts, azobisisoheptanenitrile) was added, and the reaction was carried out at 50°C for 14 hours to obtain the first system. The first system and the fourth organic solvent (120 parts, cyclohexane) were centrifuged at 10,000 rpm for 60 min until precipitation was complete. The precipitate was recovered to obtain the second system. The second system was cleaned three times with a fifth organic solvent (60 parts, anhydrous ethanol), and then dried to obtain the polymer resin, namely poly(isoborneol acrylate-co-polyethylene glycol methacrylate). Vacuum drying was used to achieve constant weight.

[0065] Example 10 This embodiment provides an optical film, the preparation steps of which are the same as those in Embodiment 1, the only difference being: (1) Preparation of polymer resin In a nitrogen atmosphere, polyethylene glycol methacrylate (40 parts, average molecular weight 300), isobornyl acrylate (60 parts) and a third organic solvent (180 parts, acetone) were added to a reaction vessel in proportion. After the substances were completely dissolved, an initiator (0.3 parts, diisopropyl peroxide) was added. The reaction was carried out at 45°C for 20 hours to obtain the first system. The first system and the fourth organic solvent (150 parts, cyclohexane) were centrifuged at 10,000 rpm for 60 min until precipitation was complete. The precipitate was recovered to obtain the second system. The second system was cleaned five times with a fifth organic solvent (100 parts, anhydrous ethanol), and then dried to obtain the polymer resin, namely poly(isoborneol acrylate-co-polyethylene glycol methacrylate). Vacuum drying was used to achieve constant weight.

[0066] Comparative Example 1 This comparative example provides an optical film, the preparation steps of which include the following: (1) Preparation of nano-zirconia dispersion 20 parts of nano-zirconia (particle size 21.84 nm) were added to anhydrous ethanol (400 parts), ultrasonically dispersed, and then a coupling agent (2 parts, vinyltriethoxysilane) was added. The mixture was modified at 50 °C for 4 h with auxiliary stirring during the process. After the reaction was completed, the mixture was centrifuged and washed three times with anhydrous ethanol. The resulting material was ultrasonically dispersed in the first organic solvent (propylene glycol ethyl ether) to obtain a nano-zirconia dispersion with a solid content of 25%.

[0067] (2) Preparation of optical film The preparation steps are the same as those in Example 1 (3) for preparing the optical film.

[0068] Comparative Example 2 This comparative example provides an optical film whose preparation steps are the same as those in Example 1, with the only difference being: (2) Preparation of nano-zirconia dispersion 20 parts of nano-zirconia (particle size 22.68 nm) were added to anhydrous ethanol (400 parts), ultrasonically dispersed, and then a coupling agent (2 parts, vinyltriethoxysilane) was added. The mixture was modified at 50 °C for 4 h with auxiliary stirring during the process to obtain an intermediate product. After the reaction was completed, the intermediate product was washed three times by centrifugation with anhydrous ethanol and ultrasonically dispersed in acetone to obtain an intermediate product dispersion.

[0069] The polymer resin (0.5 parts) obtained in step (1) was added to the above intermediate product dispersion and reacted at 50°C for 3 hours with auxiliary stirring. After the reaction was completed, the product was washed three times by centrifugation with anhydrous ethanol. The solid product was ultrasonically dispersed in the first organic solvent (propylene glycol ethyl ether) to obtain a nano-zirconia dispersion with a solid content of 25%.

[0070] Comparative Example 3 This comparative example provides an optical film whose preparation steps are the same as those in Example 4, with the only difference being: (2) Preparation of nano-zirconia dispersion 30 parts of nano-zirconia (particle size 19.05 nm) were added to anhydrous ethanol (500 parts), ultrasonically dispersed, and then a coupling agent (2 parts, vinyltris(2-methoxyethoxy)silane) was added. The mixture was modified at 50 °C for 6 h with auxiliary stirring during the process to obtain an intermediate product. After the reaction was completed, the mixture was washed three times by centrifugation with anhydrous ethanol. The obtained substance was ultrasonically dispersed in acetone to obtain an intermediate product dispersion.

[0071] The polymer resin (0.5 parts) obtained in step 1 was added to the above intermediate product dispersion and reacted at 50°C for 6 hours with auxiliary stirring. After the reaction was completed, the product was washed three times by centrifugation with anhydrous ethanol. The solid product was ultrasonically dispersed in the first organic solvent (ethylene glycol ethyl ether) to obtain a nano-zirconia dispersion with a solid content of 25%.

[0072] Comparative Example 4 This comparative example provides an optical film whose preparation steps are the same as those in Example 1, with the only difference being: (2) Preparation of nano-zirconia dispersion 20 parts of nano-zirconia (particle size 27.09 nm) were added to anhydrous ethanol (400 parts), ultrasonically dispersed, and then a coupling agent (2 parts, vinyltris(2-methoxyethoxy)silane) was added. The mixture was modified at 50 °C for 4 h with auxiliary stirring during the process to obtain an intermediate product. After the reaction was completed, the mixture was centrifuged and washed three times with anhydrous ethanol. The obtained substance was ultrasonically dispersed in acetone to obtain an intermediate product dispersion.

[0073] The polymer resin (8 parts) obtained in step (1) was added to the above intermediate product dispersion and reacted at 50°C for 5 hours with auxiliary stirring. After the reaction was completed, the product was washed three times by centrifugation with anhydrous ethanol. The solid product was ultrasonically dispersed in the first organic solvent (propylene glycol ethyl ether) to obtain a nano-zirconia dispersion with a solid content of 25%.

[0074] Comparative Example 5 This comparative example provides an optical film, the preparation steps of which include the following: (1) Preparation of nano-zirconia dispersion 20 parts of nano-zirconia (particle size 27.75 nm) were added to anhydrous ethanol (400 parts), ultrasonically dispersed, and then a coupling agent (2 parts, vinyltriethoxysilane) was added. The mixture was modified at 50 °C for 4 h with auxiliary stirring during the process to obtain an intermediate product. After the reaction was completed, the mixture was centrifuged and washed three times with anhydrous ethanol. The obtained substance was ultrasonically dispersed in acetone to obtain an intermediate product dispersion.

[0075] Three parts of polyethylene glycol methacrylate were added to the above intermediate product dispersion and reacted at 50°C for 3 hours with auxiliary stirring. After the reaction was completed, the product was washed three times by centrifugation with anhydrous ethanol. The solid product was then ultrasonically dispersed in the first organic solvent (propylene glycol ethyl ether) to obtain a nano-zirconia dispersion with a solid content of 25%.

[0076] (2) Preparation of optical film The preparation steps are the same as those in Example 1 (3) for preparing the optical film.

[0077] Comparative Example 6 This comparative example provides an optical film, the preparation steps of which include the following: (1) Preparation of nano-zirconia dispersion 20 parts of nano-zirconia (particle size 16.61 nm) were added to anhydrous ethanol (400 parts), ultrasonically dispersed, and then a coupling agent (2 parts, vinyltriethoxysilane) was added. The mixture was modified at 50 °C for 4 h with auxiliary stirring during the process to obtain an intermediate product. After the reaction was completed, the mixture was centrifuged and washed three times with anhydrous ethanol. The obtained substance was ultrasonically dispersed in acetone to obtain an intermediate product dispersion.

[0078] Three parts of isoborneol acrylate were added to the above intermediate product dispersion and reacted at 50°C for 5 hours with auxiliary stirring. After the reaction was completed, the product was washed three times by centrifugation with anhydrous ethanol. The solid product was then ultrasonically dispersed in the first organic solvent (propylene glycol ethyl ether) to obtain a nano-zirconia dispersion with a solid content of 25%.

[0079] (2) Preparation of optical film The preparation steps are the same as those in Example 1 (3) for preparing the optical film.

[0080] Test Example 1 In this test example, the optical films prepared in Examples 1-10 and Comparative Examples 1-6 were subjected to the following performance tests, including the following performance items: (1) Flexibility: Flexibility was determined according to GB / T 1731-2020 standard.

[0081] (2) Hardness: The pencil hardness was measured according to the JIS K5600 standard.

[0082] (3) Light transmission uniformity: Thickness and transmittance were measured using an ellipsometer. At least 1,000 points were scanned for each optical film, and the light transmission uniformity was evaluated by the relative range of thickness and transmittance.

[0083] (4) Transmittance and haze: Transmittance and haze were measured in accordance with ASTM D1003 standard.

[0084] The test results are shown in Tables 1 (Examples 1-10) to 2 (Comparative Examples 1-6).

[0085] Table 1 Performance results of Examples 1-10

[0086] Table 2 Performance results of Comparative Examples 1-6

[0087] As can be seen from the test results in Tables 1-2, the optical films prepared in Examples 1-10 of this invention have good performance parameters: the obtained optical films have good flexibility (≤2mm), high hardness (≥H), good light transmission uniformity (relative difference between thickness and transmittance ≤1%), light transmittance (≥90%), and haze (≤0.5%), and excellent overall performance.

[0088] Comparative Example 1, which did not use polymer resin to modify nano-zirconia, showed varying degrees of decrease in the flexibility, hardness, light transmission uniformity, light transmittance, and haze performance of the resulting optical film. This indicates that polymer resin modification can simultaneously enhance the flexibility and hardness of the optical film by introducing specific flexible and rigid functional groups. At the same time, the addition of polymer resin optimized the uniformity of the dispersion system and significantly improved the optical performance of the optical film.

[0089] Comparative Examples 2 and 3 had limited modification effects and limited improvement in optical film performance due to insufficient addition of polymer resin.

[0090] In Comparative Example 4, excessive addition of polymer resin resulted in unreacted polymer resin residues that caused structural defects in the optical film, ultimately leading to a decline in the overall performance of the optical film.

[0091] Comparative Examples 5 and 6 used polyethylene glycol methacrylate and isobornyl acrylate as modifiers, respectively. Due to the lack of specific functional group structures, they could not synergistically optimize the flexibility, hardness and optical properties of the optical film, ultimately resulting in the overall performance of the optical film not meeting expectations.

[0092] In summary, the flexible segments of polyethylene glycol methacrylate in the polymer resin of the nano-zirconia dispersion provided by the embodiments of the present invention can provide better flexibility for the optical film, while the bridged ring structure of isoborneol acrylate can form a network structure with high cross-linking density during film formation and reduce internal stress during photocuring, thereby providing better hardness performance for the optical film. The addition of nano-sized zirconia particles significantly improves the dispersion uniformity of zirconia and reduces light scattering, thereby improving the transmittance and transmittance uniformity of the optical film and reducing film haze. It is expected to be widely used in cutting-edge fields such as high-precision optical systems and flexible displays.

[0093] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A nano-zirconium oxide dispersion liquid characterized by, The nano-zirconia dispersion comprises, by weight, the following components: 23-47 parts of modified nano-zirconia and 40-190 parts of a first organic solvent; the modifier of the modified nano-zirconia comprises 1-3 parts of a coupling agent and 2-4 parts of a polymer resin. The polymer resin is poly(isoborneol acrylate-co-polyethylene glycol methacrylate).

2. The nanometer zirconium oxide dispersion liquid according to claim 1, characterized by, The particle size of the nano-zirconia is 10nm-30nm; And / or, the polymer resin comprises polyethylene glycol methacrylate and isoborneol acrylate in a weight ratio of 2:3 to 3:

1. And / or, the coupling agent is selected from at least one of silane coupling agents, titanate coupling agents, and aluminate coupling agents; And / or, the first organic solvent is selected from at least one of ethanol, acetone, propylene glycol methyl ether, ethylene glycol methyl ether, propylene glycol ethyl ether, methyl isobutyl ketone, and ethylene glycol ethyl ether; And / or, the average molecular weight of the polyethylene glycol methacrylate is 300-1000; And / or, the solid content of the nano-zirconia dispersion is 20%-35%.

3. The nanometer zirconium oxide dispersion of claim 1, wherein The raw materials for preparing the polymer resin, by weight, include 270-430 parts of a second organic solvent and 0.1-0.3 parts of an initiator; The second organic solvent comprises 120-180 parts of a third organic solvent, 100-150 parts of a fourth organic solvent, and 50-100 parts of a fifth organic solvent; wherein the third organic solvent is selected from at least one of methanol, ethyl acetate, dimethylacetamide, acetone, and dichloromethane; the fourth organic solvent is selected from at least one of diethyl ether and cyclohexane; and the fifth organic solvent is selected from at least one of ethanol and diethyl ether. And / or, the initiator is selected from at least one of azobisisobutyronitrile, azobisisoheptanenitrile, and diisopropyl peroxide dicarbonate.

4. A method for producing the nanometer zirconium oxide dispersion liquid according to any one of claims 1 to 3, characterized by, Includes the following steps: The intermediate product was obtained by modifying nano-zirconia with a coupling agent at a temperature of 40℃-70℃ for 2h-8h. The intermediate product is mixed with polymer resin in a certain proportion and reacted at a temperature of 40℃-60℃ for 2h-5h to obtain modified nano-zirconia.

5. The preparation method according to claim 4, characterized in that, The preparation of the polymer resin includes the following steps: In a protective atmosphere, polyethylene glycol methacrylate, isobornyl acrylate, initiator and third organic solvent are mixed in proportion and reacted at 30℃-80℃ for 12h-20h to obtain the first system. The first system and the fourth organic solvent were centrifuged at 4000 rpm-10000 rpm for 30 min-60 min to obtain the second system. The second system was cleaned with a fifth organic solvent and then dried to obtain a polymer resin.

6. The preparation method according to claim 4, characterized in that, After the intermediate product reacts with the polymer resin, it further includes: The product system was cleaned with an alcohol solution, and the cleaned solid material was dispersed in a first organic solvent to obtain a nano-zirconia dispersion.

7. An optical coating liquid, characterized in that, By weight, it includes 40-80 parts of the nano-zirconia dispersion as described in any one of claims 1-3 or the nano-zirconia dispersion prepared by the preparation method as described in any one of claims 4-6, 0.5-1.0 parts of photoinitiator, and 0.5-1.5 parts of leveling agent.

8. The optical coating liquid according to claim 7, characterized in that, The photoinitiator is selected from at least one of 1-hydroxycyclohexylphenyl ketone, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide, methyl benzoylformate, 2,2-dimethoxy-2-phenylacetophenone and 2-methyl-1-(4-methylthiophenyl)-2-morpholino-1-propanone; And / or, the leveling agent is selected from at least one of BYK-301, BYK-333, BYK-332 and BYK-348; And / or, an optical coating is prepared by uniformly mixing nano-zirconia dispersion, photoinitiator and leveling agent in a certain proportion.

9. An optical film, characterized in that, The optical coating liquid as described in any one of claims 7-8 is coated onto the surface of a substrate and then photocured. The substrate is selected from at least one of polyethylene terephthalate, polyethylene naphthalate, polymethyl methacrylate, polybutylene terephthalate, polyamide-imide and cellulose triacetate; The optical film has at least one of the following characteristics: flexibility ≤2mm, hardness ≥H, thickness relative range ≤1%, transmittance relative range ≤1%, light transmittance ≥90%, and haze ≤0.5%.

10. The application of the optical film as described in claim 9 in display devices, optical communications, and optical instruments.

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