Modified metal oxides, their preparation methods, solutions, optical films and applications

Abstract

This application discloses a modified metal oxide, its preparation method, adhesive, optical film, and application. The modified metal oxide comprises a metal oxide and an acrylate monomer containing organic UV-absorbing groups, wherein the metal oxide and the acrylate monomer containing organic UV-absorbing groups are linked by a mercaptosilane coupling agent. The acrylate monomer containing organic UV-absorbing groups in the modified metal oxide can both reduce the catalytic degradation of the acrylate resin in the coating by the modified metal oxide and improve the compatibility between the modified metal oxide and the acrylate resin, thus comprehensively improving the coating's aging resistance, yellowing resistance, and stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of nanoparticles, in particular to a modified metal oxide, a preparation method thereof, a glue solution, an optical film and applications. BACKGROUND

[0002] In many application fields at present, such as optical communication technology, photonic computer, display panel, high refractive index materials are needed to be used for photon integration to increase system efficiency or to protect devices. However, the refractive index of most photocuring resins is relatively low, for example, the refractive index of acrylate resin is usually in the range of 1.4-1.55, and it is usually necessary to add a certain amount of inorganic nanoparticles, such as titanium dioxide nanoparticles and zirconium dioxide nanoparticles, to the photocuring resin to improve the refractive index of the photocuring resin. However, metal nanoparticles have photocatalytic effect under UV light irradiation, which can cause degradation of the photocuring resin, resulting in deterioration of the performance of the photocuring resin system.

[0003] Generally, ultraviolet absorbers are added to the system to improve the ultraviolet resistance of the photocuring resin system containing metal nanoparticles. However, since the added ultraviolet absorbers are usually high molecular organic substances, they are prone to precipitation or sedimentation during use due to mismatch with the formulation system, thereby reducing the stability, light transmittance and refractive index of the photocuring resin system. Moreover, a sufficient amount of ultraviolet absorbers must be added to achieve a certain ultraviolet resistance effect, and the addition of a large amount of ultraviolet absorbers can seriously affect the transparency of the photocuring resin system. In addition, the incompatibility of the ultraviolet absorbers with the photocuring resin system can result in the ultraviolet absorbers not being uniformly wrapped on the surface of the metal nanoparticles, greatly weakening the ultraviolet resistance of the photocuring resin system.

[0004] Therefore, in order to meet market demand, it is necessary to design a modified metal oxide with ultraviolet resistance to reduce the degree of catalytic degradation of the modified nanoparticles on the photocuring resin. SUMMARY

[0005] Therefore, the technical problem to be solved by the present application is to overcome the above-mentioned defects in the prior art, and the purpose is to provide a modified metal oxide, in which an acrylate monomer containing an organic UV absorbing group is grafted to the surface of the metal oxide. The organic UV absorbing group can absorb ultraviolet light, which can not only reduce the degree of catalytic degradation of the modified metal oxide on the acrylate resin in the coating, but also improve the compatibility between the modified metal oxide and the acrylate resin.

[0006] In a first aspect, the present application provides a modified metal oxide, comprising a metal oxide and an acrylate monomer containing an organic UV absorbing group, wherein the metal oxide and the acrylate monomer containing an organic UV absorbing group are connected by a mercaptosilane coupling agent.

[0007] The acrylate monomer containing organic UV absorbing group is grafted to the surface of the metal oxide by mercapto silane coupling agent to reduce the absorption of the metal oxide in the modified metal oxide to the ultraviolet light, thereby reducing the photocatalytic degradation effect of the modified metal oxide to the acrylate resin, improving the anti-aging performance of the coating, and since the acrylate monomer containing organic UV absorbing group is coated on the surface of the metal oxide, a small amount of acrylate monomer containing organic UV absorbing group can significantly reduce the ultraviolet light absorption of the metal oxide in the modified metal oxide, reducing the influence of the introduction of the acrylate monomer containing organic UV absorbing group on the refractive index of the modified metal oxide. In addition, the metal oxide modified by the acrylate monomer containing organic UV absorbing group can improve the compatibility between the modified metal oxide and the acrylate resin, not only can make the modified metal oxide uniformly dispersed in the acrylate resin, but also can make the modified metal oxide and the acrylate resin closely combined, and comprehensively improve the stability and strength of the coating.

[0008] In any embodiment, the average particle size of the modified metal oxide is 10-100 nm, which can be 12-80 nm or 12-40 nm, and more preferably 15-30 nm.

[0009] The smaller the average particle size of the modified metal oxide, the more conducive to improving the transparency of the coating formed by the subsequent modified metal oxide and the acrylate resin, and the more conducive to reducing the absorption of the modified metal oxide to the ultraviolet light, significantly reducing the degradation degree of the modified metal oxide to the acrylate resin, and improving the anti-aging performance of the coating.

[0010] In any embodiment, the average particle size of the metal oxide is 3-80 nm, which can be 5-50 nm or 5-30 nm, and more preferably 10-20 nm.

[0011] In any embodiment, the mass content of the metal oxide based on the total mass of the modified metal oxide is 80-97%, which can be 85-92%.

[0012] Controlling the mass content of the metal oxide within a suitable range is conducive to reducing the influence of the addition of the acrylate monomer containing organic UV absorbing group on the refractive index of the modified metal oxide, so that the coating prepared by the modified metal oxide and the acrylate resin has excellent refractive index, and the anti-yellowing performance of the modified metal oxide is improved, and the anti-yellowing performance of the coating is significantly improved.

[0013] In any embodiment, the acrylate monomer containing organic UV absorbing group includes the structure shown in formula I and the structure shown in formula II,

[0014]

[0015]

[0016] wherein, represents a connecting site.

[0017] In any embodiment, the acrylate monomer containing organic UV absorbing group further comprises a compound having a structure of Formula III,

[0018]

[0019] wherein, represents a connecting site.

[0020] The structure of Formula III in the modified metal oxide as a polar group and having a certain strength is beneficial to improve the mechanical strength and toughness of the modified metal oxide, thereby reducing the risk of the modified metal oxide being broken in the subsequent mixing and stirring process with the acrylate resin or the formed glue solution in the imprinting process. At the same time, the structure of Formula III in the modified metal oxide can form a strong hydrogen bond with the acrylate resin, thereby improving the strength of the coating. Moreover, the modified metal oxide having the structure of Formula III has high compatibility with the acrylate resin, reduces the risk of agglomeration of the modified metal oxide, and improves the stability of the coating.

[0021] In any embodiment, the acrylate monomer containing organic UV absorbing group comprises a compound having a structure of Formula IV,

[0022]

[0023] wherein, R1 comprises one or more of substituted or unsubstituted C 1-5 alkylene, R2, R3, R4 each independently comprises at least one of hydrogen bond, substituted or unsubstituted C 1-5 alkyl, R5 comprises R6, R7, R8, R9 and R 10 each independently comprises substituted or unsubstituted C 1-5 alkyl, substituted or unsubstituted phenyl, hydroxyl, amino, at least one of R8, R9 and R 10 comprises at least one of at least one of R8, R9 and R

[0024] In any embodiment, the acrylate monomer containing an organic UV absorbing group includes a structure derived from an isocyanate-containing acrylate monomer including a compound having a structure according to Formula V and a hydroxyphenyltriazine compound including a compound having a structure according to Formula VI,

[0025]

[0026] R 11 including one or more of substituted or unsubstituted C 1-5 alkylene, R 12 and R 13 each independently include at least one of a hydrogen bond, substituted or unsubstituted C 1-5 alkyl, R 14 , R 15 , R 16 , R 17 and R 18 each independently include at least one of substituted or unsubstituted C 1-5 alkyl, substituted or unsubstituted phenyl, hydroxyl, amino, and R 16 , R 17 and R 18 include at least one of hydroxyl, amino.

[0027] In any embodiment, the mercapto silane coupling agent has a general formula of SH-R 20 -Si-(OC m H 2m+1 )3, where R 20 includes one or more of substituted or unsubstituted C 1-5 alkylene, and m is 1, 2, 3, 4, or 5.

[0028] In a second aspect of the present application, a method of preparing a modified metal oxide is provided, the method comprising:

[0029] reacting a metal oxide and a mercapto silane coupling agent in a first reaction to produce a mercapto-modified metal oxide;

[0030] reacting an isocyanate-containing acrylate monomer and a hydroxyphenyltriazine compound in a second reaction to produce an acrylate monomer containing an organic UV absorbing group;

[0031] reacting the mercapto-modified metal oxide and the acrylate monomer containing an organic UV absorbing group in a mercapto-dual bond addition reaction to produce the modified metal oxide.

[0032] The metal oxide surface has hydroxyl groups, which can react with the mercapto silane coupling agent to realize the surface modification of the metal oxide by the mercapto silane coupling agent. The acrylate monomer and the triazine compound are reacted through the hydroxyl-isocyanate group to prepare an acrylate monomer containing an organic UV absorption group. Finally, the mercapto group in the modified metal oxide and the carbon-carbon double bond in the acrylate monomer containing the organic UV absorption group are added by the photoinitiation to prepare the modified metal oxide. The prepared modified metal oxide has excellent anti-ultraviolet performance and high refractive index.

[0033] In a third aspect of the present application, a glue solution is provided, comprising a photoinitiator, an acrylate compound and the modified metal oxide provided in the first aspect of the present application or prepared by the preparation method provided in the second aspect of the present application.

[0034] In a fourth aspect of the present application, an optical film is provided, comprising a substrate and a coating layer on one side of the substrate, wherein the coating layer is prepared from the glue solution provided in the third aspect of the present application.

[0035] In any embodiment, the thickness of the coating layer is 200 nm to 5000 nm, which can be 300 nm to 3000 nm.

[0036] In any embodiment, the mass content of the modified metal oxide in the coating layer is 40% to 85%, which can be 60% to 80%.

[0037] In a fifth aspect of the present application, the optical film in any embodiment is applied in the field of nanoimprint and diffractive optical waveguide devices. DETAILED DESCRIPTION

[0038] The ranges disclosed in the present application are defined in the form of lower limit and upper limit, a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundary of a particular range. The ranges defined in this way can be inclusive of the end values or not, and can be arbitrarily combined, i.e. any lower limit can be combined with any upper limit to form a range. For example, the numerical range "a-b" represents a shorthand notation for any real combination between a and b, where a and b are real numbers. For example, the numerical range "0-7" represents that all real numbers between "0-7" have been listed herein, and "0-7" is only a shorthand notation for these numerical combinations. In addition, when it is stated that a parameter is an integer ≥3, it is equivalent to disclose that the parameter is, for example, an integer 3, 4, 5, 6, 7, 8, 9, 10, 11, etc.

[0039] If not specifically stated, all embodiments and optional embodiments of the present application can be combined with each other to form new technical solutions.

[0040] If not otherwise specified, all technical features and optional technical features of the present application can be combined with each other to form new technical solutions.

[0041] If not otherwise specified, all steps of the present application can be performed in sequence or randomly, preferably in sequence. For example, the method comprises steps (1) and (2) means that the method can comprise steps (1) and (2) in sequence, or steps (2) and (1) in sequence. For example, it is mentioned that the method can further comprise step (3), which means that step (3) can be added to the method in any order, for example, the method can comprise steps (1), (2) and (3), or steps (1), (3) and (2), or steps (3), (1) and (2), etc.

[0042] If not otherwise specified, the terms “comprise” and “include” mentioned in the present application mean open-ended, and can also mean closed-ended. For example, the “comprise” and “include” can mean that other components not listed can also be included, or only the listed components can be included.

[0043] If not otherwise specified, in the present application, the term “or” is inclusive. For example, the phrase “A or B” means “A, B, or both A and B”. More specifically, either of the following conditions satisfies the condition “A or B”: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or A and B are both true (or exist).

[0044] The present application proposes a modified metal oxide, comprising a metal oxide and an acrylate monomer containing an organic UV absorption group, the metal oxide and the acrylate monomer containing an organic UV absorption group being connected by a mercapto silane coupling agent.

[0045] In this context, the term “metal oxide” refers to metal oxide nanoparticles having a high refractive index and a surface having hydroxyl groups. The refractive index of the metal oxide is ≥1.6, and the metal oxide includes but is not limited to TiO2, Fe2O3, WO3, ZrO2, Cu2O or SnO2.

[0046] In this context, the term “acrylate monomer containing an organic UV absorption group” refers to an acrylate monomer in which at least one hydrogen is replaced by a UV absorption group and its derivatives, i.e. having both a UV absorption group and an acrylate group, or having both a UV absorption group and a group derived from an acrylate. The UV group includes but is not limited to represents a connection site, and the acrylate group or the group derived from the acrylate includes but is not limited to represents a connection site.

[0047] In this document, the term "mercaptosilane coupling agent" refers to a silane coupling agent containing -SH-. Mercaptosilane coupling agents include, but are not limited to, 3-mercaptopropyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, or γ-mercaptopropyltriethoxysilane.

[0048] In this paper, modified metal oxides were prepared by chemically reacting a mercaptosilane coupling agent with metal oxides and acrylate monomers containing organic UV-absorbing groups, respectively, thereby achieving the modification of metal oxides by acrylate monomers containing organic UV-absorbing groups.

[0049] This application utilizes a mercaptosilane coupling agent to graft acrylate monomers containing organic UV-absorbing groups onto the surface of a metal oxide. This reduces the absorption of ultraviolet light by the modified metal oxide, thereby reducing the photocatalytic degradation effect of the modified metal oxide on the acrylate resin and improving the aging resistance of the coating. Furthermore, because the acrylate monomers containing organic UV-absorbing groups are grafted onto the surface of the metal oxide, effective coating of the metal oxide with these groups is achieved. A small amount of acrylate monomers containing organic UV-absorbing groups can significantly reduce the ultraviolet light absorption of the modified metal oxide, thus reducing the impact of the introduction of these monomers on the refractive index of the modified metal oxide. This comprehensively improves the stability, transparency, and refractive index of the acrylic resin coating. Simultaneously, the metal oxide modified with acrylate monomers containing organic UV-absorbing groups enhances the compatibility between the modified metal oxide and the acrylate resin. This not only allows the modified metal oxide to be uniformly dispersed in the acrylate resin but also ensures a tighter bond between the modified metal oxide and the acrylate resin, comprehensively improving the stability and strength of the coating.

[0050] Furthermore, the study also found that, compared to conventional silane coupling agents, the mercaptosilane coupling agent in this application has a higher refractive index, which enables the modified metal oxide to have a high refractive index, thus facilitating the preparation of high refractive index coatings. Moreover, the study also found that, compared to traditional silane coupling agents, the mercaptosilane coupling agent used in this application to attach acrylate monomers containing organic UV-absorbing groups to the surface of metal oxides not only enables the coatings prepared from modified metal oxides to have superior resistance to yellowing and aging, but also enables the coatings prepared from modified metal oxides to have a lower initial yellowness value.

[0051] In this document, the term "acrylate resin" refers to a compound containing carbon-carbon double bonds and ester bonds, and may also be an acrylate compound; acrylate compounds include, but are not limited to, 2-phenoxyethyl acrylate, benzyl acrylate, 3-phenoxybenzyl acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, 2-acrylate-[[1,1-binaphthyl]-2,2-di(oxy-2,1-ethidel)] ester, ethoxybisphenol A diacrylate, or tri(2-hydroxyethyl)isocyanurate triacrylate.

[0052] In this document, the term "coating" refers to a coating formed by curing modified metal oxides and acrylate resins under the action of a photocuring agent. The coating may also include, but is not limited to, some solvents and functional additives, such as diluents, dispersants, leveling agents or wetting agents, and the coating may be widely used in various optical products.

[0053] In this article, the term "yellowing" refers to the changes in the internal molecular chains and molecular structure of a coating under ultraviolet irradiation. These changes are reflected on the material surface as yellowing, and the degree of yellowing or yellowing of the coating is usually characterized by yellowness value.

[0054] In some embodiments, the average particle size of the modified metal oxide is 10 nm to 100 nm. In some embodiments, the average particle size of the modified metal oxide may be selected from 10 nm, 20 nm, 30 nm, 40 nm, 50 nm, 60 nm, 70 nm, 80 nm, 90 nm, 100 nm, or a value within the range formed by any two of the above points.

[0055] In this paper, the term "average particle size" refers to the particle size that reaches 50% of the volumetric cumulative size in the particle size distribution of modified nanoparticles, measured from the smallest particle size.

[0056] Smaller average particle size of modified metal oxides not only improves the transparency of the coating formed by the modified metal oxides and acrylic resin, but also reduces the absorption of ultraviolet light by the modified metal oxides, significantly reducing the degradation of the acrylic resin by the modified metal oxides and improving the aging resistance of the coating. However, excessively small average particle size of the modified metal oxides can exacerbate agglomeration between them, affecting the uniform dispersion of the modified metal oxides in the acrylic resin. Therefore, controlling the average particle size of the modified metal oxides within a suitable range can achieve superior optical performance.

[0057] In some embodiments, the average particle size of the metal oxide is 3 nm to 80 nm. In some embodiments, the average particle size of the metal oxide can be selected from 3 nm, 5 nm, 8 nm, 10 nm, 15 nm, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm, 80 nm, or a value within the range formed by any two of the above points.

[0058] The average particle size of the metal oxide is controlled within a suitable range so that the average particle size of the prepared modified metal oxide is within a suitable range, taking into account both the stability and dispersibility of the modified metal oxide.

[0059] In some embodiments, the acrylate monomers of the organic UV-absorbing groups include the structures shown in Formula I and Formula II.

[0060]

[0061] in, Indicates the connection site.

[0062] The group shown in Formula II can absorb ultraviolet light: the intramolecular hydrogen bond formed between the hydroxyl hydrogen on its benzene ring and the adjacent nitrogen atom constitutes a chelate ring. When ultraviolet light is absorbed, the molecule undergoes thermal vibration, the hydrogen bond breaks, the chelate ring opens, and an ionic compound is formed. This compound is in an unstable high-energy state. To return to the original low-energy stable state, the excess energy is released as other energies, and the chelate ring closes again, thus achieving ultraviolet light absorption in a cyclical manner. The group shown in Formula II can absorb ultraviolet light over a wide wavelength range with high absorption efficiency. Furthermore, its low luster allows for high transparency in the adhesive formed between the modified metal oxide and acrylate resin, broadening the application range of the adhesive. In addition, the group shown in Formula II has two rigid ring structures, and its steric hindrance effect can effectively reduce the aggregation between modified metal oxides, which is beneficial for reducing the average particle size of the modified metal oxides and improving the dispersion stability of the modified metal oxides in the acrylate resin system.

[0063] In some embodiments, the acrylate monomer containing organic UV-absorbing groups further includes the structure shown in Formula III.

[0064]

[0065] in, Indicates the connection site.

[0066] The structure shown in Formula III of the modified metal oxide, as a polar group with a certain strength, is beneficial to improving the mechanical strength and toughness of the modified metal oxide, thereby reducing the risk of breakage of the modified metal oxide during subsequent mixing with acrylate resin or during the imprinting process. At the same time, the structure shown in Formula III of the modified metal oxide can form strong hydrogen bonds with acrylate resin, thereby improving the strength and stability of the coating. Moreover, the modified metal oxide with the structure shown in Formula III has high compatibility with acrylate resin, reducing the risk of agglomeration between modified metal oxides and improving the stability of the coating.

[0067] In some embodiments, the acrylate monomer containing organic UV-absorbing groups includes compounds with the structure shown in Formula IV.

[0068]

[0069] R1 includes substituted or unsubstituted C. 1-5 One or more of the alkylene groups, where R2, R3, and R4 each independently include hydrogen bonds, substituted or unsubstituted carbon atoms. 1-5 At least one of the alkyl groups, R5 includes R6, R7, R8, R9 and R 10 Each independently includes substituted or unsubstituted C 1-5 Alkyl, substituted or unsubstituted phenyl, hydroxyl, amino At least one of them, and R8, R9 and R 10 At least one of them includes At least one of them, * indicates a connection site.

[0070] In some implementations, R2 and R3 are both hydrogen bonds.

[0071] In some embodiments, the acrylate monomer containing organic UV-absorbing groups includes structures derived from hydroxyl-containing acrylate monomers and triazine compounds containing isocyanates.

[0072] In some embodiments, the acrylate monomer containing organic UV-absorbing groups includes structures derived from isocyanate-containing acrylate monomers and hydroxyphenyltriazine compounds.

[0073] Acrylate monomers containing organic UV-absorbing groups can be prepared by combining acrylate monomers and triazine compounds through the reaction between hydroxyl groups and isocyanate groups. The resulting urethane groups are beneficial for improving the strength and dispersibility of modified metal oxides.

[0074] In some embodiments, the isocyanate-containing acrylate monomers include compounds with the structure shown in Formula V, and the hydroxyphenyltriazine compounds include compounds with the structure shown in Formula VI.

[0075]

[0076]

[0077] R 11 Including substituted or unsubstituted C 1-5 One or more of the alkylene groups, R 12 and R 13 Each independently includes hydrogen bonds, substituted or unsubstituted C atoms. 1-5 At least one of the alkyl groups, R 14 R 15 R 16 R 17 and R 18 Each independently includes substituted or unsubstituted C 1-5 At least one of alkyl, substituted or unsubstituted phenyl, hydroxyl, and amino groups, and R 16 R 17 and R 18 At least one of the following is included: hydroxyl or amino.

[0078] In some implementations, R 16 R 17 and R 18 At least one of them includes a hydroxyl group. In some embodiments, R 16 It is a hydroxyl group

[0079] In some implementations, R 11 It is ethylene, R 12 and R 13 The compounds with hydrogen bonds, i.e., the structure shown in Formula IV, are

[0080] In this document, the term "substituted or unsubstituted" means that the group may be unsubstituted or substituted. The substituent may be halogen, amino, nitro, mercapto, cyano, hydroxyl, alkoxy containing 1 to 8 carbons, acyl containing 1 to 8 carbons, aryl, arylalkyl, amino, amide, alkylthio or arylthio.

[0081] Understandably, R 16 R 17 and R 18At least one of them contains a hydroxyl group, and acrylate monomers containing organic UV-absorbing groups can be prepared by reacting hydroxy-isocyanate groups; in addition, hydroxyphenyl triazine compounds are broad-spectrum absorbers with high UV absorption efficiency, and hydroxyphenyl triazine compounds have the advantages of low color and high refractive index, so that the coating has high transparency and refractive index, reduces the initial yellowness value of the coating, and broadens the application field of modified metal oxides.

[0082] In some embodiments, the general formula of the mercaptosilane coupling agent is SH-R. 20 -Si-(OC m H 2m+1 )3, where R 20 Including substituted or unsubstituted C 1-5 One or more of the alkylene groups, where m is 1, 2, 3, 4 or 5.

[0083] In some embodiments, the metal oxide includes at least one selected from TiO2, SnO2, CeO2, GeO2, Ta2O5, Bi4Ti3O2, Nb2O5, ITO, HfO2, MoO3, Sb2O3, Sb2O5, Nd2O3, and ZrO2. In some embodiments, the metal oxide is TiO2. In some embodiments, the metal oxide is ZrO2.

[0084] In some embodiments, the crystal form of the metal oxide includes at least one of rutile, anatase, and brookite. In some embodiments, the crystal form of the metal oxide is rutile.

[0085] Grafting acrylate monomers containing organic UV-absorbing groups onto the surface of metal oxides can reduce the absorption of ultraviolet light by the three crystal forms of the modified metal oxides mentioned above. Among them, rutile metal oxides have a more stable structure, a faster rate of electron-hole pair recombination on the surface, low photocatalytic activity, and excellent ultraviolet light shielding ability, which further helps to reduce the photocatalytic effect of the modified metal oxides.

[0086] In some embodiments, the isocyanate-containing acrylate monomer includes at least one selected from ethyl isocyanate, ethyl isocyanate methacrylate, butyl isocyanate, and isooctyl isocyanate. In some embodiments, the isocyanate-containing acrylate monomer includes ethyl isocyanate. In some embodiments, the isocyanate-containing acrylate monomer includes butyl isocyanate.

[0087] In some embodiments, hydroxyphenyltriazine compounds include (Formula V-1) (Formula V-2) At least one of (Formula V-3). In some embodiments, the hydroxyphenyltriazine compound is In some embodiments, hydroxyphenyltriazine compounds are

[0088] All of the above-mentioned hydroxyphenyltriazine compounds can be reacted with the above-mentioned acrylate monomers containing isocyanates to prepare acrylate monomers containing organic UV-absorbing groups, which can then be grafted onto the surface of metal oxides via mercaptosilane coupling agents.

[0089] In some embodiments, the mercaptosilane coupling agent includes at least one selected from γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, 2-mercaptoethyltriethoxysilane, and 3-mercaptopropyl(dimethoxy)silane. In some embodiments, the mercaptosilane coupling agent is γ-mercaptopropyltrimethoxysilane. In some embodiments, the mercaptosilane coupling agent is γ-mercaptopropyltriethoxysilane.

[0090] In some embodiments, the mass content of the metal oxide is 80% to 97% based on the total mass of the modified metal oxide. In some embodiments, the mass content of the metal oxide may be selected from 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, or a value within a range consisting of any two of the above.

[0091] Controlling the mass content of metal oxides within a suitable range helps to reduce the influence of the addition of acrylate monomers containing organic UV-absorbing groups on the refractive index of modified metal oxides, so that the coating prepared by modified metal oxides and acrylic resin has an excellent refractive index, and can also improve the yellowing resistance of modified metal oxides, thus significantly improving the yellowing resistance and aging resistance of the coating.

[0092] This application also provides a method for preparing a modified metal oxide, the method comprising:

[0093] A first reaction is carried out between a metal oxide and a mercaptosilane coupling agent to prepare a mercapto-modified metal oxide;

[0094] An acrylate monomer containing an organic UV-absorbing group is prepared by reacting an acrylate monomer containing an isocyanate with a hydroxyphenyl triazine compound, or by reacting an acrylate monomer containing a hydroxyl group with a triazine compound containing an isocyanate.

[0095] Modified metal oxides are prepared by thiol-modified metal oxides and acrylate monomers containing organic UV-absorbing groups undergoing a thiol-double bond addition reaction.

[0096] The surface of metal oxides contains hydroxyl groups, which can react with the silicon-oxygen bonds in mercaptosilane coupling agents to achieve surface modification of metal oxides by the mercaptosilane coupling agents. Acrylate monomers and triazine compounds are reacted with hydroxy-isocyanate groups to prepare acrylate monomers containing organic UV-absorbing groups. Finally, the mercapto groups in the metal oxide are modified with mercapto groups, and the carbon-carbon double bonds in the acrylate monomers containing organic UV-absorbing groups undergo a photoinitiated addition reaction to prepare the modified metal oxides. This preparation method is simple, uses readily available raw materials, has low production costs, and the prepared modified metal oxides exhibit excellent UV resistance and high refractive index.

[0097] In addition, mercaptosilane coupling agents have high reactivity with acrylate monomers containing organic UV absorbing groups, enabling rapid grafting of acrylate monomers containing organic UV absorbing groups onto the particle surface.

[0098] In some embodiments, the reaction temperature of the first reaction is 50–80°C, and the reaction time of the first reaction is 3–8 hours. In some embodiments, the reaction temperature of the first reaction can be selected as 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, or a value within the range formed by any two of the above points, and the reaction time of the first reaction is 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, or a value within the range formed by any two of the above points.

[0099] The reaction temperature and reaction time of the first reaction are controlled within a suitable range to allow the mercaptosilane coupling agent to fully react with the hydroxyl groups on the surface of the metal oxide, so as to provide enough reaction sites for the subsequent reaction of acrylate monomers containing organic UV-absorbing groups.

[0100] In some embodiments, the reaction temperature of the second reaction is 50°C to 80°C, and the reaction time is 2 hours to 5 hours. In some embodiments, the reaction temperature of the second reaction can be selected as 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, 80°C, or a value within the range formed by any two of the above points, and the reaction time of the second reaction can be 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, or a value within the range formed by any two of the above points.

[0101] By controlling the reaction temperature and reaction time of the second reaction within a suitable range, the acrylate monomer containing hydroxyl or isocyanate groups and the triazine compound containing isocyanate or hydroxyl groups can be fully reacted to prepare the acrylate monomer containing organic UV-absorbing groups.

[0102] In some embodiments, the photoinitiator in the thiol-double bond addition reaction includes at least one of photoinitiator TPO, photoinitiator 184, photoinitiator TPO-L, photoinitiator 819, and photoinitiator ITX; the UV light in the thiol-double bond addition reaction includes at least one of mercury lamp and UV LED; and the light intensity power of the thiol-double bond addition reaction is 30 mW / cm². 2 ~300mw / cm 2 In some embodiments, the photoinitiator in the thiol-double bond addition reaction is the photoinitiator TPO, the UV light in the thiol-double bond addition reaction is a UV LED, and the light intensity power in the thiol-double bond addition reaction can be selected as 30 mW / cm². 2 50mw / cm 2 80mw / cm 2 100mw / cm 2 120mw / cm 2 150mw / cm 2 180mw / cm 2 200mw / cm 2 220mw / cm 2 250mw / cm 2 280mw / cm 2 300mw / cm 2 The value within the range formed by any two of the above points.

[0103] By controlling the photoinitiation reaction in the thiol-double bond addition reaction under appropriate conditions, the addition reaction between the acrylate monomer containing organic UV absorbing groups and the thiol silane coupling agent is made to precede the self-polymerization reaction of the acrylate monomer containing organic UV absorbing groups. This enables the acrylate monomer containing organic UV absorbing groups to be successfully grafted onto the metal oxide, thereby reducing the degree of self-polymerization of the acrylate monomer containing organic UV absorbing groups.

[0104] In some embodiments, the mass ratio of the metal oxide to the mercaptosilane coupling agent is 10:1 to 40:1. In some embodiments, the mass ratio of the metal oxide to the mercaptosilane coupling agent can be selected as 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 26:1, 27:1, 28:1, 29:1, 30:1, 31:1, 32:1, 33:1, 34:1, 35:1, 36:1, 37:1, 38:1, 39:1, 40:1, or a value within the range formed by any two of the above.

[0105] In some embodiments, the mass ratio of the metal oxide to the acrylate monomer containing the organic UV-absorbing group is 10:1 to 30:1. In some embodiments, the mass ratio of the metal oxide to the acrylate monomer containing the organic UV-absorbing group can be selected as 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 26:1, 27:1, 28:1, 28:1, 29:1, 30:1, or a value within the range formed by any two of the above.

[0106] By controlling the mass ratio of metal oxide to mercaptosilane coupling agent and acrylate monomer containing organic UV absorbing groups within a suitable range, sufficient reaction between mercaptosilane coupling agent, acrylate monomer containing organic UV absorbing groups and metal oxide can be provided, while avoiding waste caused by excessive mercaptosilane coupling agent and acrylate monomer containing organic UV absorbing groups, as well as the increase in difficulty of subsequent processing.

[0107] This application also provides an adhesive liquid comprising a photoinitiator, an acrylate compound, and a modified metal oxide as described in some embodiments or a modified metal oxide prepared by the preparation method described in some embodiments.

[0108] In some embodiments, the acrylate compounds include at least one selected from 2-phenoxyethyl acrylate, benzyl acrylate, 3-phenoxybenzyl acrylate, 9,9-bis(4-(2-acryloyloxyethoxy)phenyl)fluorene, 2-acrylate, ((1,1-binaphthyl)-2,2-di(oxy-2,1-ethide)) ester, ethoxybisphenol A diacrylate, 4-acryloylmorpholine, N-vinylpyrrolidone, and tri(2-hydroxyethyl)isocyanurate triacrylate.

[0109] The modified metal oxides can be stably dispersed in the aforementioned acrylate compounds and have excellent compatibility with acrylate compounds, significantly improving the stability of the adhesive. More importantly, the modified metal oxides contain UV-absorbing groups, which can effectively reduce the absorption of ultraviolet light by the metal oxides in the modified metal oxides, thereby greatly reducing the degradation effect of the metal oxides in the modified metal oxides on the acrylate compounds and significantly improving the yellowing resistance of the coating prepared by the adhesive.

[0110] In some embodiments, the adhesive further includes a solvent, which includes at least one selected from propylene glycol methyl ether, propylene glycol methyl ether acetate, methyl ethyl ketone, methyl isobutyl ketone, butyl acetate, and ethanol. In some embodiments, the solvent includes propylene glycol methyl ether. In some embodiments, the solvent includes methyl isobutyl ketone. In some embodiments, the solvent includes both propylene glycol methyl ether and methyl isobutyl ketone.

[0111] The addition of solvents helps to reduce the viscosity of the adhesive and improve the coating process.

[0112] This application also provides an optical film, including a substrate and a coating located on one side of the substrate, the coating being prepared from the adhesive solution provided in this application.

[0113] Acrylic monomers containing organic UV-absorbing groups can not only reduce the degradation of acrylate compounds caused by the absorption of ultraviolet light by metal oxides in modified metal oxides, but also reduce the impact of ultraviolet light on acrylate compounds, thus comprehensively improving the coating's resistance to yellowing and aging.

[0114] The coating in this application has a low initial yellowness value and a high refractive index.

[0115] In some embodiments, the coating thickness is 200 nm to 5000 nm. In some embodiments, the coating thickness can be selected from 200 nm, 300 nm, 500 nm, 1000 nm, 1500 nm, 2000 nm, 2500 nm, 3000 nm, 3500 nm, 4000 nm, 4500 nm, 5000 nm, or a value within the range formed by any two of the above points.

[0116] By controlling the coating thickness within a suitable range, the requirements for coating strength and refractive index can be balanced.

[0117] In some embodiments, the mass content of the modified metal oxide in the coating is 40% to 85%. In some embodiments, the mass content of the modified metal oxide in the coating can be selected as 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or a value within a range consisting of any two of the above.

[0118] By controlling the mass content of modified metal oxides in the coating within a suitable range, the stability, initial yellowness value, and refractive index of the coating can be balanced.

[0119] In some implementations, the coating has a refractive index higher than 1.65.

[0120] The coating in this application has a high refractive index and can be widely used in the optical field.

[0121] In some embodiments, the optical film further includes a substrate, which includes at least one of ceramic, glass, metal, natural or artificial stone, polymer material, paint, powder coating, wood, and fiber substrate.

[0122] This application also provides some embodiments of the application of optical films in nanoimprint and diffractive waveguide devices.

[0123] The optical film in this application has excellent optical properties, such as high transparency and refractive index, low yellowness value, excellent aging resistance and stability, and can be widely used in nanoimprinting, AR, VR and optical communication fields.

[0124] Example

[0125] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. The reaction illustrations are for a more intuitive understanding of the occurrence of the reactions and do not limit the specific process and course of the reactions. Where specific experimental steps or conditions are not specified in the embodiments, they can be performed according to the conventional experimental steps or conditions described in the literature in this field. Reagents or instruments used, unless otherwise specified, are all commercially available conventional reagent products.

[0126] I. Preparation Method

[0127] Example 1:

[0128] 1) Preparation of modified metal oxides

[0129] Thiol-modified metal oxides: 8g of TiO2 (purchased from Sigma-Aldrich, average particle size 12nm), 50mL of anhydrous ethanol, and 10mL of pure water were placed in a 150mL flask and ultrasonically dispersed for 1h. Then, 0.5g of γ-mercaptopropyltrimethoxysilane was added, and the pH was adjusted to 4 with glacial acetic acid. The mixture was refluxed at 80℃ for 3h, and then centrifuged to obtain a slurry. Finally, the slurry was washed with anhydrous ethanol and centrifuged four times, and then vacuum dried at 100℃ for 8h to obtain thiol-modified TiO2 particles. The reaction diagram for preparing thiol-modified TiO2 particles is shown below:

[0130]

[0131] Synthesis of acrylate monomers containing organic UV-absorbing groups: 10g of the substance with the structure shown in Formula V-1 was added to 20ml of ethyl acetate and placed in a 100ml flask. The mixture was stirred and dissolved. Then, 3.6g of ethyl isocyanate (purchased from Sigma-Aldrich) and 0.08g of dibutyltin dilaurate catalyst were added. The mixture was reacted at 60℃ for 3h. The solvent was removed by rotary evaporation to obtain the acrylate monomers containing organic UV-absorbing groups. The reaction diagram for preparing the acrylate monomers containing organic UV-absorbing groups is shown below:

[0132]

[0133] Take 10g of mercapto-modified TiO2 particles and 12ml of propylene glycol methyl ether acetate, place them in a 50mL flask, and ultrasonically disperse for 1h. Then add 0.3g of photoinitiator TPO and 1.1g of the above-mentioned acrylate monomer containing organic UV-absorbing groups. Place the flask in a 365nm light curing chamber with a light intensity power set to 30mw / cm². 2 The mixture was stirred and reacted for 30 minutes, then centrifuged, washed, and dried to obtain modified TiO2. The reaction diagram for preparing modified TiO2 is shown below:

[0134]

[0135] 2) Preparation of adhesive solution

[0136] Take 4.5g of the above modified TiO2 and dissolve it in 10ml of propylene glycol methyl ether acetate. Add 0.1g of photoinitiator TPO, then add 0.5g of 1,6-hexanediol diacrylate and 0.5g of trimethylolpropane triacrylate. Add 0.02g of leveling agent BYK354 and disperse at 600rpm magnetic stirring for 2h to obtain the adhesive solution.

[0137] 3) Preparation of optical films

[0138] A 4-inch diameter glass slide was placed on a Laurell spin coater. 2 ml of the aforementioned adhesive solution was dropped onto the slide using a pipette to prepare a coating. The spin coater operated at 3000 rpm for 30 seconds. The slide was then baked on an 80°C hot plate for 1 minute and cured under a 365 nm UV-LED at a curing energy of 5000 mJ / cm². 2 To prepare optical films.

[0139] Examples 2-4

[0140] The modified metal oxides, adhesives, and coatings of Examples 2-4 are prepared in a similar manner to those of Example 1, except that the amount of metal oxide added in Example 1 was adjusted so that the mass content of metal oxide in the modified metal oxides was 80%, 92%, and 97%, respectively, as shown in Table 1.

[0141] Example 5

[0142] The modified metal oxide, adhesive, and coating of Example 5 are prepared in a similar manner to those of Example 1, except that the type of mercaptosilane coupling agent in Example 1 is adjusted so that the mercaptosilane coupling agent is γ-mercaptopropyltrimethoxysilane, as shown in Table 1.

[0143] Example 6

[0144] The modified metal oxide, adhesive, and coating of Example 6 are prepared in a similar manner to those of Example 5, except that the amount of metal oxide added in Example 5 was adjusted so that the mass content of the metal oxide in the modified metal oxide was 92%, as shown in Table 1.

[0145] Example 7

[0146] The modified metal oxide, adhesive, and coating of Example 7 are prepared in a similar manner to those of Example 1, except that the types of triazine compounds in Example 1 are adjusted so that the triazine compounds are substances with the structure shown in Formula V-3, as detailed in Table 1.

[0147] Example 8

[0148] The modified metal oxide, adhesive, and coating of Example 8 are prepared in a similar manner to those of Example 7, except that the average particle size of the metal oxide in Example 7 was adjusted to be 10 nm, as detailed in Table 1.

[0149] Examples 9-12

[0150] The modified metal oxides, colloids, and coatings of Examples 9-12 are prepared in a similar manner to those of Example 1, except that the average particle size of the metal oxides in Example 1 was adjusted so that the average particle sizes of the metal oxides were 10 nm, 5 nm, 20 nm, and 80 nm, respectively, as shown in Table 1.

[0151] Examples 13-15

[0152] The modified metal oxides, adhesives, and coatings of Examples 13-15 are prepared in a similar manner to those of Example 1, except that the mass content of the modified metal oxides in the coatings of Example 1 was adjusted so that the mass content of the metal oxides in the coatings was 50%, 65%, and 85%, respectively, as shown in Table 1.

[0153] Example 16

[0154] The modified metal oxide, adhesive, and coating of Example 16 are prepared in a similar manner to those of Example 1, except that the type of metal oxide in Example 1 is adjusted so that the metal oxide is ZrO2, as shown in Table 1.

[0155] Examples 17-18

[0156] The modified metal oxides, adhesives, and coatings of Examples 17 and 18 are prepared in a similar manner to those of Example 1, except that the amount of metal oxide added in Example 16 was adjusted so that the mass content of the metal oxide in the modified metal oxide was 70% and 92%, respectively, as shown in Table 1.

[0157] Comparative Example 1

[0158] 1) Preparation of modified metal oxides

[0159] Thiol-modified metal oxides: 8g of TiO2 (purchased from Sigma-Aldrich, average particle size 12nm), 50mL of anhydrous ethanol and 10mL of pure water were placed in a 150mL flask and ultrasonically dispersed for 1h. Then, 1.4g of γ-mercaptopropyltrimethoxysilane was added, and the pH was adjusted to 4 with glacial acetic acid. The mixture was refluxed at 80℃ for 3h. The solution was then centrifuged to obtain a slurry. Finally, the slurry was washed with anhydrous ethanol and centrifuged 4 times. The slurry was then vacuum dried at 100℃ for 8h to obtain thiol-modified TiO2 particles.

[0160] 2) Preparation of adhesive solution

[0161] Take 4.5g of the above-mentioned mercapto-modified TiO2 particles and dissolve them in 10ml of propylene glycol methyl ether acetate. Add 0.1g of photoinitiator TPO, then add 0.5g of 1,6-hexanediol diacrylate and 0.5g of trimethylolpropane triacrylate. Add 0.02g of leveling agent BYK354 and disperse the mixture at 600rpm under magnetic stirring for 2h to obtain the adhesive solution.

[0162] 3) Preparation of optical films

[0163] A 4-inch diameter glass slide was placed on a Laurell spin coater, and 2 ml of the above-mentioned adhesive solution was dropped onto the glass slide using a pipette to prepare a coating. The spin coating speed was 3000 rpm and the spin time was 30 s. The glass slide was then placed on an 80°C hot plate and baked for 1 min, and then cured under a 365nm UV-LED with a curing energy of 5000 mJ to prepare an optical film.

[0164] Comparative Example 2

[0165] 1) Preparation of modified metal oxides

[0166] Thiol-modified metal oxides: 8g of TiO2 (purchased from Sigma-Aldrich, average particle size 12nm), 50mL of anhydrous ethanol and 10mL of pure water were placed in a 150mL flask and ultrasonically dispersed for 1h. Then, 0.5g of γ-mercaptopropyltrimethoxysilane was added, and the pH was adjusted to 4 with glacial acetic acid. The mixture was refluxed at 80℃ for 3h. The solution was then centrifuged to obtain a slurry. Finally, the slurry was washed with anhydrous ethanol and centrifuged 4 times. The slurry was then vacuum dried at 100℃ for 8h to obtain thiol-modified TiO2 particles.

[0167] 2) Preparation of adhesive solution

[0168] Dissolve 7.2g of the above-mentioned mercapto-modified TiO2 particles in 10ml of propylene glycol methyl ether acetate, add 0.1g of photoinitiator TPO and 0.77g of triazine UV absorber UV-405 (purchased from Sigma-Aldrich), then add 0.5g of 1,6-hexanediol diacrylate and 0.5g of trimethylolpropane triacrylate, and add 0.02g of leveling agent BYK354. Disperse the mixture at 600rpm magnetic stirring for 2h to obtain the adhesive solution.

[0169] 3) Preparation of optical films

[0170] A 4-inch diameter glass slide was placed on a Laurell spin coater, and 2 ml of the above-mentioned adhesive solution was dropped onto the glass slide using a pipette to prepare a coating. The spin coating speed was 3000 rpm and the spin time was 30 s. The glass slide was then placed on an 80°C hot plate and baked for 1 min, and then cured under a 365nm UV-LED with a curing energy of 5000 mJ to prepare an optical film.

[0171] The structure of UV405 is as follows:

[0172] Comparative Example 3

[0173] 1) Preparation of modified metal oxides

[0174] Thiol-modified metal oxides: 9.7 g of TiO2 (purchased from Sigma-Aldrich, with an average particle size of 12 nm), 50 mL of anhydrous ethanol and 10 mL of pure water were placed in a 150 mL flask and ultrasonically dispersed for 1 h. Then, 0.5 g of γ-mercaptopropyltrimethoxysilane was added, and the pH was adjusted to 4 with glacial acetic acid. The mixture was refluxed at 80 °C for 3 h. The solution was then centrifuged to obtain a slurry. Finally, the slurry was washed with anhydrous ethanol and centrifuged 4 times. The slurry was then vacuum dried at 100 °C for 8 h to obtain thiol-modified TiO2 particles.

[0175] 2) Preparation of adhesive solution

[0176] Take 7.2g of the above-mentioned mercapto-modified TiO2 particles and dissolve them in 10ml of propylene glycol methyl ether acetate. Add 0.1g of photoinitiator TPO and 1.27g of triazine UV absorber UV-405, then add 0.25g of 1,6-hexanediol diacrylate and 0.25g of trimethylolpropane triacrylate, and add 0.02g of leveling agent BYK354. Disperse the mixture under magnetic stirring at 600rpm for 2h to obtain the adhesive solution.

[0177] 3) Preparation of optical films

[0178] A 4-inch diameter glass slide was placed on a Laurell spin coater, and 2 ml of the above-mentioned adhesive solution was dropped onto the glass slide using a pipette to prepare a coating. The spin coating speed was 3000 rpm and the spin time was 30 s. The glass slide was then placed on an 80°C hot plate and baked for 1 min, and then cured under a 365nm UV-LED with a curing energy of 5000 mJ to prepare an optical film.

[0179] Comparative Example 4

[0180] The modified metal oxide, adhesive, and coating of Example 4 are prepared in a similar manner to those of Comparative Example 3, except that the type of triazine UV absorber in Comparative Example 3 is adjusted so that the triazine UV absorber is UV-1600 (purchased from Sigma-Aldrich), as detailed in Table 2.

[0181] The structural formula of UV1600 is:

[0182] Comparative Example 5

[0183] The modified metal oxide, adhesive, and coating of Example 5 are prepared in a similar manner to those of Comparative Example 3, except that the type of triazine UV absorber in Comparative Example 3 is adjusted so that the triazine UV absorber is UV-531 (purchased from Sigma-Aldrich), as detailed in Table 2.

[0184] The structural formula of UV531 is:

[0185] Comparative Example 6

[0186] 1) Preparation of modified metal oxides

[0187] Thiol-modified metal oxides: 8g of TiO2 (purchased from Sigma-Aldrich, average particle size 12nm), 50mL of anhydrous ethanol and 10mL of pure water were placed in a 150mL flask and ultrasonically dispersed for 1h. Then, 0.5g of γ-mercaptopropyltrimethoxysilane was added, and the pH was adjusted to 4 with glacial acetic acid. The mixture was refluxed at 80℃ for 3h. The solution was then centrifuged to obtain a slurry. Finally, the slurry was washed with anhydrous ethanol and centrifuged 4 times. The slurry was then vacuum dried at 100℃ for 8h to obtain thiol-modified TiO2 particles.

[0188] 2) Preparation of adhesive solution

[0189] Take 16g of the above-mentioned mercapto-modified TiO2 particles and dissolve them in 10ml of propylene glycol methyl ether acetate. Add 0.1g of photoinitiator TPO and 2.9g of triazine UV absorber UV-405, then add 0.5g of 1,6-hexanediol diacrylate and 0.5g of trimethylolpropane triacrylate, and add 0.02g of leveling agent BYK354. Disperse the mixture under magnetic stirring at 600rpm for 2h to obtain the adhesive solution.

[0190] 3) Preparation of optical films

[0191] A 4-inch diameter glass slide was placed on a Laurell spin coater, and 2 ml of the above-mentioned adhesive solution was dropped onto the glass slide using a pipette to prepare a coating. The spin coating speed was 3000 rpm and the spin time was 30 s. The glass slide was then placed on an 80°C hot plate and baked for 1 min, and then cured under a 365nm UV-LED with a curing energy of 5000 mJ to prepare an optical film.

[0192] Comparative Example 7

[0193] The modified metal oxide, adhesive, and coating of Comparative Example 7 were prepared in a similar manner to those of Comparative Example 3, except that the type of metal oxide in Comparative Example 3 was adjusted to be ZrO2, as detailed in Table 2.

[0194] Table 1. Preparation parameters of modified metal oxides and coatings in the examples.

[0195]

[0196]

[0197] Table 2. Preparation parameters of modified metal oxides and coatings for comparative examples.

[0198]

[0199] "-" indicates that the corresponding substance is not added.

[0200] II. Testing Methods

[0201] 1) Test of average particle size

[0202] The average particle size of the modified metal oxide was tested according to GB / T 19077.1-2003 standard. The modified metal oxide to be tested was dissolved in propylene glycol methyl ether acetate solvent to form a concentration, wherein the mass ratio of the modified metal oxide to propylene glycol methyl ether acetate was 1:3000. The mixture was ultrasonically dispersed for 10 min, and the particle size distribution curve of the modified metal oxide was obtained using a Horiba SZ-100V2 nanoparticle size analyzer. The average particle size of the modified metal oxide can be directly obtained from the particle size distribution curve.

[0203] 2) Optical film transmittance test

[0204] The transmittance of the modified metal oxide optical film was tested according to GB 2410-2008 standard. The transmittance of the optical film prepared on the glass substrate was tested in the range of 400nm to 800nm ​​using a UV-vis spectrophotometer. The testing equipment was a Shimadzu UV-1800.

[0205] 3) Optical film haze test

[0206] The haze of modified metal oxide optical films was tested according to GB 2410-80 standard. Optical films prepared on glass substrates were tested using a haze meter, specifically the Nippon Denshoku NDH8000 model.

[0207] 4) Testing the yellowness value of the coating

[0208] Before UV aging: The optical film prepared on the glass substrate was tested using a colorimeter. The testing equipment model was X-Rite Ci7800 from the United States.

[0209] After UV aging: The optical film prepared on the glass substrate was subjected to an aging test using UV 340nm, power 0.63w, and light irradiation for 96h. Then, the yellowness value was tested using X-Rite Ci7800.

[0210] 5) Refractive index and thickness of the coating

[0211] Before UV aging: The thin film prepared on the glass substrate was tested using an ellipsometer. The testing equipment model was Semilab SE-2000.

[0212] After UV aging: The optical film prepared on the glass substrate was subjected to an aging test using UV 340nm, power 0.63w, and light irradiation for 96h. Then, the refractive index and thickness were tested using Semilab SE-2000.

[0213] Table 3 Performance test table for each embodiment and comparative example

[0214]

[0215]

[0216] III. Analysis of Test Results for Each Embodiment and Comparative Example

[0217] As can be seen from the comparison of Examples 1-4, Example 7 and Comparative Example 1, compared with traditional silane-modified metal oxides, the metal oxides modified by acrylate monomers containing organic UV-absorbing groups in this application can effectively improve the aging resistance of the coating and extend the service life of the coating.

[0218] As can be seen from the comparison of Examples 1-4, Example 7 with Comparative Examples 2-6, and Examples 16-18 with Comparative Example 7, compared with the traditional mixture of silane-modified metal oxides and conventional UV absorbers, the acrylate monomers containing organic UV absorbing groups grafted onto the surface of metal oxides by mercaptosilane coupling agents in this application can effectively improve the aging resistance of the coating and extend the service life of the coating.

[0219] As can be seen from Examples 1 to 4, the higher the content of metal oxide in the modified metal oxide, the more beneficial it is to reduce the haze of the coating and improve the light transmittance of the coating.

[0220] As can be seen from Examples 1-18 and Comparative Examples 1-7, ultraviolet light irradiation causes a reduction in coating thickness. The reasons are as follows: 1) After absorbing ultraviolet light, the metal oxides (e.g., TiO2 or ZrO2) in the modified nanoparticles undergo photocatalytic degradation of the acrylate resin, leading to a decrease in the molecular weight of the acrylate resin and causing it to detach, resulting in a reduction in coating thickness; 2) After absorbing ultraviolet light, the acrylate resin itself undergoes slow degradation, leading to a decrease in the molecular weight of the acrylate resin and causing it to detach. The detachment of the acrylate resin reduces the adhesion between the modified metal oxide and the coating, further causing the modified metal oxide to detach, resulting in a reduction in coating thickness. A comparison between Examples 1-18 and Comparative Examples 1-7 shows that, compared to traditional methods without UV absorbers or with conventional UV absorbers added during the preparation of the adhesive, the coating prepared using metal oxides modified with organic UV-absorbing groups and acrylate resin in this application exhibits superior UV resistance, with a significantly reduced coating thickness before and after UV aging.

[0221] As can be seen from Examples 1-4, 5-6, and 16-18, based on the total mass of the modified metal oxides, controlling the mass content of the metal oxides to be 80%-97% can give the coating containing the modified metal oxides excellent refractive index, transmittance, haze, yellowness value, and aging resistance. As the mass content of the metal oxides in the modified metal oxides decreases, it is beneficial to improve the aging resistance of the coating. When the mass content of the metal oxides in the modified metal oxides is too low, the refractive index of the coating is relatively low after aging.

[0222] As seen in Examples 1, 9-12, and 7-8, controlling the average particle size of the metal oxide to be 5 nm to 80 nm allows the modified metal oxide to have a suitable average particle size, resulting in coatings containing the modified metal oxide exhibiting excellent refractive index, transmittance, haze, yellowness value, and aging resistance. Decreasing the average particle size of the modified metal oxide is beneficial for improving the haze and aging resistance of the coating; however, when the average particle size of the modified metal oxide is too low, the yellowness value of the coating after aging is relatively high.

[0223] As can be seen from Examples 1 and 13-15, controlling the mass content of modified metal oxides in the coating to be 50%-85% can give the coating containing modified metal oxides excellent refractive index, transmittance, haze, yellowness value, and aging resistance. Decreasing the mass content of modified metal oxides in the coating is beneficial to improving the aging resistance of the coating; when the mass content of modified metal oxides in the coating is too low, the refractive index of the coating after aging is relatively low.

[0224] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A modified metal oxide for use in an optical film, characterized by, The metal oxide and the acrylate monomer containing an organic UV absorption group are connected by a mercapto silane coupling agent, the average particle size of the modified metal oxide is 10nm~100nm, The acrylate monomer containing an organic UV absorption group comprises a compound shown in the structure of formula IV, Formula IV, R1 includes substituted or unsubstituted C. 1-5 One of the alkylene groups, where R2, R3, and R4 each independently include hydrogen bonds, substituted or unsubstituted carbon atoms. 1-5 At least one of the alkyl groups, R5 includes R6, R7, R8, R9 and R 10 Each independently includes substituted or unsubstituted C 1-5 Alkyl, substituted or unsubstituted phenyl, hydroxyl, amino , At least one of them, and R8, R9 and R 10 At least one of them includes , One of them, * indicates a connection site.

2. The modified metal oxide of claim 1, wherein The average particle size of the modified metal oxide is 12nm~80nm.

3. The modified metal oxide of claim 1, wherein The average particle size of the modified metal oxide is 12nm~40nm.

4. The modified metal oxide of claim 1, wherein The average particle size of the modified metal oxide is 15nm~30nm.

5. The modified metal oxide of claim 1, wherein, The average particle size of the metal oxide is 3nm~80nm.

6. The modified metal oxide of claim 1, wherein, The average particle size of the metal oxide is 5nm~50nm.

7. The modified metal oxide of claim 1, wherein, The average particle size of the metal oxide is 5nm~30nm.

8. The modified metal oxide of claim 1, wherein, The average particle size of the metal oxide is 10nm~20nm.

9. The modified metal oxide of claim 1, wherein, The mass content of the metal oxide is 80%~97% based on the total mass of the modified metal oxide.

10. The modified metal oxide of claim 1, wherein, The mass content of the metal oxide is 85%~92% based on the total mass of the modified metal oxide.

11. The modified metal oxide according to any one of claims 1 to 10, characterized in that, The acrylate monomer containing an organic UV absorption group comprises a structure shown in formula I, a structure shown in formula II and a structure shown in formula III, Formula I, Formula II, Formula III, wherein represents a connection site.

12. The modified metal oxide according to any one of claims 1 to 10, characterized in that, The acrylate monomer containing an organic UV absorption group comprises a structure derived from an isocyanate-containing acrylate monomer and a hydroxyphenyl triazine compound, the isocyanate-containing acrylate monomer comprises a compound shown in the structure of formula V, and the hydroxyphenyl triazine compound comprises a compound shown in the structure of formula VI, Formula V, Formula VI, R 11 one of substituted or unsubstituted C 1-5 alkylene, R 12 and R 13 each independently include at least one of a hydrogen bond, substituted or unsubstituted C 1-5 alkyl, R 14 , R 15 , R 16 , R 17 and R 18 each independently include at least one of substituted or unsubstituted C 1-5 alkyl, substituted or unsubstituted phenyl, hydroxyl, amino, and R 16 , R 17 and R 18 include at least one of hydroxyl, amino.

13. The modified metal oxide according to any one of claims 1 to 10, characterized in that, The thiol silane coupling agent has a general formula of SH-R 20 -Si-(OC m H 2m+1 )3, wherein R 20 comprises one of a substituted or unsubstituted C 1-5 alkylene group, and m is 1, 2, 3, 4, or 5.

14. The modified metal oxide of claim 11, wherein, The metal oxide comprises at least one of TiO2, SnO2, CeO2, GeO2, Ta2O5, Bi4Ti3O2, Nb2O5, ITO, HfO2, MoO3, Sb2O3, Sb2O5, Nd2O3 and ZrO2.

15. The modified metal oxide of claim 14, wherein, The metal oxide comprises at least one of ZrO2 and TiO2.

16. The modified metal oxide of claim 12, wherein, The isocyanate-containing acrylate monomer comprises at least one of isocyanate acrylate ethyl ester, isocyanate methacrylate ethyl ester, isocyanate acrylate butyl ester and isocyanate acrylate iso-octyl ester.

17. The modified metal oxide of claim 16, wherein, The isocyanate-containing acrylate monomer comprises at least one of isocyanate acrylate ethyl ester and isocyanate methacrylate ethyl ester.

18. The modified metal oxide of claim 12, wherein, The hydroxyphenyl triazines include at least one of , , .

19. The modified metal oxide of claim 18, wherein, The hydroxyphenyl triazines include .

20. The modified metal oxide of claim 1, wherein, The mercapto silane coupling agent comprises at least one of γ-mercaptopropyl trimethoxysilane, γ-mercaptopropyl triethoxysilane, 2-mercaptoethyl triethoxysilane and 3-mercaptopropyl (dimethoxy) silane.

21. The modified metal oxide of claim 20, wherein, The mercapto silane coupling agent comprises at least one of γ-mercaptopropyl trimethoxysilane and γ-mercaptopropyl triethoxysilane.

22. A method of producing the modified metal oxide according to any one of claims 1 to 21, characterized by, The preparation method comprises: The metal oxide and the mercapto silane coupling agent are subjected to a first reaction to prepare a mercapto-modified metal oxide; The isocyanate-containing acrylate monomer and the hydroxyphenyl triazine compound are subjected to a second reaction, or the hydroxyl-containing acrylate monomer and the isocyanate-containing triazine compound are subjected to a second reaction to prepare the acrylate monomer containing an organic UV absorption group; The thiol-modified metal oxide and the acrylate monomer containing organic UV absorbing group are subjected to a thiol-double bond addition reaction to prepare the modified metal oxide.

23. The method of claim 22, wherein, The reaction temperature of the first reaction is 50-80℃, and the reaction time of the first reaction is 3-8h.

24. The method of claim 22, wherein, The reaction temperature of the first reaction is 50-80℃, and the reaction time of the first reaction is 4-6h.

25. The preparation method according to claim 22, characterized in that, The reaction temperature of the first reaction is 60-70℃, and the reaction time of the first reaction is 3-8h.

26. The method of claim 22, wherein, The reaction temperature of the first reaction is 60-70℃, and the reaction time of the first reaction is 4-6h.

27. The method of claim 22, wherein, The reaction temperature of the second reaction is 50-80℃, and the reaction time of the second reaction is 2-5h.

28. The method of claim 22, wherein, The reaction temperature of the second reaction is 55-70℃, and the reaction time of the second reaction is 2-5h.

29. The method of claim 22, wherein, The reaction temperature of the second reaction is 50-80℃, and the reaction time of the second reaction is 2.5-4h.

30. The method of claim 22, wherein, The reaction temperature of the second reaction is 55-70℃, and the reaction time of the second reaction is 2.5-4h.

31. The method of claim 22, wherein, The photo initiator in the thiol-double bond addition reaction includes at least one of photo initiator TPO, photo initiator 184, photo initiator TPO-L, photo initiator 819, photo initiator ITX, the UV light in the thiol-double bond addition reaction includes at least one of mercury lamp, UV LED, and the light intensity power in the thiol-double bond addition reaction is 30 mw / cm 2 300 mw / cm 2 .

32. The method of claim 22, wherein, The mass ratio of the metal oxide to the thiol silane coupling agent is 10:1-40:

1.

33. The method of claim 22, wherein the method is carried out at a temperature of about 20°C to about 30°C. The mass ratio of the metal oxide to the thiol silane coupling agent is 15:1-30:

1.

34. The method of claim 22, wherein the method is carried out at a temperature of about 20°C to about 30°C. The mass ratio of the metal oxide to the acrylate monomer containing organic UV absorbing group is 10:1-30:

1.

35. The method of claim 22, wherein the method is carried out at a temperature of about 20°C to about 30°C. The mass ratio of the metal oxide to the acrylate monomer containing organic UV absorbing group is 12:1-18:

1.

36. A sizing solution, characterized in that, An optical film comprising a photoinitiator, an acrylate compound and the modified metal oxide of any one of claims 1-21 or the modified metal oxide prepared by the preparation method of any one of claims 22-35.

37. An optical film characterized by, An optical film comprising a substrate and a coating layer on one side of the substrate, wherein the coating layer is prepared from the glue solution of claim 36.

38. The optical film of claim 37, wherein, The thickness of the coating layer is 200-5000nm.

39. The optical film of claim 37, wherein, The thickness of the coating layer is 300-3000nm.

40. The optical film of claim 37, wherein, The mass content of the modified metal oxide in the coating layer is 40-85%.

41. The optical film of claim 37, wherein, The mass content of the modified metal oxide in the coating layer is 50-80%.

42. The optical film of claim 37, wherein, The mass content of the modified metal oxide in the coating layer is 65-85%.

43. The optical film of claim 37, wherein, The refractive index of the coating layer is higher than 1.

6.

44. Use of the optical film of any one of claims 37-43 in the field of nanoimprinting, diffractive optical waveguide devices.

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