(METH)acrylate monomer, and preparation method therefor and use thereof

Abstract

A (meth)acrylate monomer, and a preparation method therefor and the use thereof. The structural general formulae of the (meth)acrylate monomer are as shown in formulae G1, G2 and G3, wherein R1 is methyl or hydrogen; and R2 and R3 are selected from hydrogen, Br, phenyl, methyl, or (I), where A1 in (I) is phenyl or methyl.

Description

(Meth)acrylate monomers, their preparation methods and applications

[0001] Cross-references to related applications

[0002] This application is based on and claims priority to Chinese Patent Application No. 2024119421932, filed on December 25, 2024, entitled "(Meth)acrylate monomers and their preparation methods and applications", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of holographic materials technology, and in particular to (meth)acrylate monomers, their preparation methods and applications. Background Technology

[0004] The various components used to make holographic recording media, such as photosensitive dyes, initiators, chain transfer agents, writing monomers, film-forming resins, and plasticizers, work together to determine the performance of the holographic recording media.

[0005] The migration rate and polymerization rate of the writing monomers jointly determine the grating formation speed. A faster migration rate than polymerization rate is required to obtain a grating with stable refractive index modulation. When the writing monomers located in the coherent bright region polymerize, the unreacted writing monomers in the coherent dark region rapidly migrate to the bright region, squeezing the film-forming resin from the bright region into the dark region. This makes the refractive index of the bright region close to that of the writing monomers, and the refractive index of the dark region close to that of the film-forming resin. Simultaneously, a refractive index difference between the writing monomers and the film-forming resin is necessary to form a refractive index-modulated volume holographic grating. A greater refractive index difference between the writing monomers and the film-forming resin allows the holographic recording medium to form a refractive index-modulated volume holographic grating more quickly. In existing refractive index-modulated phase-type volume holographic gratings prepared by photopolymers, the refractive index difference between the writing monomers and the film-forming resin is not significant enough, preventing the rapid construction of the refractive index-modulated volume holographic grating and affecting the performance of the holographic recording medium. Summary of the Invention

[0006] In view of this, this application proposes a (meth)acrylate monomer, its preparation method and application, aiming to achieve a high refractive index for the (meth)acrylate monomer, so as to improve the holographic optical performance of the photopolymer holographic recording medium containing the (meth)acrylate monomer.

[0007] The (meth)acrylate monomers proposed in the first aspect of this application have the general structural formulas shown in formulas G1, G2 and G3:

[0008] Wherein, R1 is methyl or hydrogen; R2 and R3 are selected from hydrogen, Br, phenyl, methyl or in A1 in the text represents either phenyl or methyl.

[0009] As can be seen from the above technical solutions, the (meth)acrylate monomers proposed in the first aspect of this application possess (meth)acrylate groups, exhibiting high refractive index and low volume shrinkage properties; they also contain aromatic ring groups with high molar refractive index and low molar volume, as well as some sulfur atoms that inherently possess high refractive index, resulting in an overall extremely high refractive index for the monomer molecule. When the monomer contains halogen and aromatic ring structures, the viscosity of the entire monomer can be controlled within a reasonable range due to the presence of alkyl chains; the molecular size of the entire monomer is relatively small, making aggregation less likely; the monomers with the above-mentioned structures of this application are easy to synthesize and obtain.

[0010] The preparation method of the (meth)acrylate monomers in the aforementioned examples according to the second aspect of this application involves adding compound P1 and compound P2 sequentially to a solvent in a molar ratio of 1:1, stirring until homogeneous, adding a catalyst and reacting for 0.5 h to 10 h, removing excess solvent by rotary evaporation after the reaction is complete, and obtaining high refractive index (meth)acrylate monomers by column chromatography.

[0011] The structural formula of compound P1 is as follows: R2 and R3 are selected from hydrogen, Br, phenyl, methyl, or... A1 in the formula is phenyl or methyl; the structural formula of compound P2 is R1 can be either methyl or hydrogen.

[0012] The method for preparing (meth)acrylate monomers proposed in the second aspect of this application has the advantages of small molecular weight of each reactant, few preparation steps, simple reaction conditions, and easy synthesis. The monomers are also less likely to aggregate during the synthesis process.

[0013] The third aspect of this application discloses a photopolymer-type holographic recording medium containing (meth)acrylate monomers, including a writing monomer, wherein the writing monomer includes the (meth)acrylate monomer and a polymerizable monomer.

[0014] The photopolymer holographic recording medium containing (meth)acrylate monomers proposed in the third aspect of this application can form a writing monomer component with a high refractive index by adding (meth)acrylate monomers and polymerizable monomers. This allows the writing monomer and the film-forming resin to have a greater refractive index difference, providing the necessary material basis for the formation of a phase-type volume holographic grating with refractive index modulation in the photopolymer holographic recording medium.

[0015] The fourth aspect of this application provides a holographic optical element, the raw material of which includes the photopolymer type holographic recording medium of the aforementioned examples.

[0016] The holographic optical element proposed in the fourth aspect of this application has excellent holographic performance, high diffraction efficiency, high sensitivity, and low required exposure amount.

[0017] An optical device is provided in the fifth aspect of this application, including the holographic optical element as described above.

[0018] The optical devices proposed in the fifth aspect of this application, such as head-up display devices, augmented reality devices, virtual reality devices, and photopolymer holographic storage optical discs, have excellent holographic performance.

[0019] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit the disclosure of the embodiments of this application. Attached Figure Description

[0020] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-a proposed in some embodiments of this application;

[0022] Figure 2 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-b proposed in some embodiments of this application.

[0023] Figure 3 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-c proposed in some embodiments of this application;

[0024] Figure 4 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-d proposed in some embodiments of this application;

[0025] Figure 5 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-e proposed in some embodiments of this application;

[0026] Figure 6 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-f proposed in some embodiments of this application;

[0027] Figure 7 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-g proposed in some embodiments of this application;

[0028] Figure 8 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-h proposed in some embodiments of this application;

[0029] Figure 9 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-i proposed in some embodiments of this application;

[0030] Figure 10 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-j proposed in some embodiments of this application.

[0031] Figure 11 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-k proposed in some embodiments of this application;

[0032] Figure 12 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with structural formula G1-l proposed in some embodiments of this application;

[0033] Figure 13 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G1-m proposed in some embodiments of this application;

[0034] Figure 14 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G2-a proposed in some embodiments of this application;

[0035] Figure 15 is a schematic diagram of the chemical reaction equations for the preparation method of (meth)acrylate monomers with the structural formula G3-a proposed in some embodiments of this application;

[0036] Figure 16 is a holographic exposure characteristic curve of photopolymer holographic recording medium 1-1 in Example 16, photopolymer holographic recording medium 2-1 in Example 17, and photopolymer holographic recording medium 3-1 in Example 18;

[0037] Figure 17 is a comparative holographic exposure characteristic curve. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] Photopolymer materials used for holographic recording utilize light to polymerize writing monomers, which then combine with film-forming resin to form a phase-type holographic grating with refractive index modulation to achieve holographic recording. In the coherent bright region, monomer polymerization is consumed, reducing its concentration, while in the coherent dark region, monomers hardly react. This difference in monomer concentration between the bright and dark regions causes monomers in the dark region to migrate towards the bright region. Simultaneously, the film-forming resin in the bright region is squeezed into the dark region. Ultimately, the refractive index of the bright region approaches the refractive index of the polymer, and the refractive index of the dark region approaches the refractive index of the film-forming resin, thus forming a phase-type volume holographic grating with refractive index modulation.

[0040] This application provides a high-refractive-index, low-viscosity (meth)acrylate monomer as a component of the writing monomer, which, when combined with an isocyanate-alcohol with a lower refractive index as a film-forming resin, forms a volume holographic grating with a greater refractive index difference, thereby improving the holographic performance of the photopolymer holographic recording medium.

[0041] Where there is no conflict, the following embodiments and features can be combined with each other.

[0042] The (meth)acrylate monomers of this application are described below.

[0043] According to the present application, a (meth)acrylate monomer has the general structural formula shown in formulas G1, G2 and G3:

[0044] Wherein, R1 is methyl or hydrogen; R2 and R3 are selected from hydrogen, Br, phenyl, methyl or in A1 in the text represents either phenyl or methyl.

[0045] As can be seen from the above technical solutions, the (meth)acrylate monomers proposed in this application possess (meth)acrylate groups, exhibiting high refractive index and low volume shrinkage. Furthermore, they contain aromatic ring groups with high molar refractive index and low molar volume, as well as sulfur atoms that inherently possess high refractive index, resulting in an overall extremely high refractive index for the monomer molecule. When the monomer contains halogen and aromatic ring structures, the viscosity of the entire monomer can be controlled within a reasonable range due to the presence of alkyl chains. The molecular size of the entire monomer is relatively small, making aggregation less likely. The monomers with the aforementioned structures in this application are easy to synthesize and obtain.

[0046] In some examples, (meth)acrylate monomers are selected from monomers having the following structural formula:

[0047] Where R1 is methyl or hydrogen. Therefore, the (meth)acrylate monomers in the above examples all have significant advantages such as high refractive index, small molecular structure, short chain length, easy migration, low self-aggregation, and low viscosity.

[0048] In some examples, the refractive index of (meth)acrylate monomers is 1.54–1.62, and the kinematic viscosity is 5–20 mm. 2 / s.

[0049] The preparation method of the (meth)acrylate monomers of this application is described below.

[0050] According to the preparation methods of (meth)acrylate monomers in the aforementioned examples of this application, compound P1 and compound P2 are added to the solvent in a molar ratio of 1:1, stirred evenly, and then a catalyst is added to react for 0.5 h to 10 h. After the reaction is completed, excess solvent is removed by rotary evaporation, and (meth)acrylate monomers are obtained by column chromatography.

[0051] The structural formula of compound P1 is as follows: R2 and R3 are selected from hydrogen, Br, phenyl, methyl, or... A1 in the formula is phenyl or methyl; the structural formula of compound P2 is R1 can be either methyl or hydrogen.

[0052] As can be seen from the above, the method for preparing (meth)acrylate monomers proposed in this application has small molecular weight of each reactant, few preparation steps, simple required reaction conditions, is easy to synthesize and operate, and the monomers are not prone to agglomeration during the synthesis process.

[0053] In some examples, compound P1 is selected from compounds having the following structural formula:

[0054] In other words, after compounds P1 and P2 with these structural formulas are synthesized, (meth)acrylate monomers with the aforementioned structural formulas can be synthesized accordingly. During the synthesis process, the structural formula is... In compound P2, where R1 is methyl or hydrogen, the C=N double bond will open, while the H in -SH in compound P1 will transfer, thus forming the polymerization of the two monomers.

[0055] In some examples, the solvent is selected from one or more of ethanol, petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, toluene, acetonitrile, N,N-dimethylformamide, or dimethyl sulfoxide. Adding these solvents allows both compounds P1 and P2 to be dissolved in the solvent, which exhibits good compatibility with both compounds and facilitates control of their concentrations, resulting in a more homogeneous reaction system. After the reaction is complete, these solvents exhibit good volatility, making it easy to remove them to obtain the desired reactant, which is then suitable for further processing.

[0056] In some examples, the catalyst is a tertiary amine catalyst or an organometallic catalyst. For example, the catalyst is selected from one or more of the following: triethylenediamine, bis(dimethylaminoethyl) ether, dimethylethanolamine, 2-(2-dimethylaminoethoxy)ethanol, trimethylhydroxyethylpropanediamine, N,N-bis(dimethylaminopropyl)isopropanolamine, dibutyltin dilaurate, stannous octoate, potassium carboxylate catalysts, and bismuth carboxylate catalysts. The catalyst is not limited to the types listed above; any catalyst capable of catalyzing the polymerization reaction of the aforementioned compounds P1 and P2 is acceptable. Those skilled in the art should understand that these all fall within the scope of protection of this application.

[0057] The following describes a photopolymer-type holographic recording medium containing (meth)acrylate monomers.

[0058] The photopolymer holographic recording medium containing (meth)acrylate monomers from the foregoing examples, as proposed in this application, includes a writing monomer, which comprises (meth)acrylate monomers and polymerizable monomers.

[0059] The photopolymer holographic recording medium containing (meth)acrylate monomers proposed in the third aspect of this application can form a writing monomer component with a high refractive index by adding (meth)acrylate monomers and polymerizable monomers. This allows the writing monomer and the film-forming resin to have a greater refractive index difference, providing the necessary material basis for the formation of a phase-type volume holographic grating with refractive index modulation in the photopolymer holographic recording medium.

[0060] In some embodiments of the application, the photopolymer-type holographic recording medium containing (meth)acrylate monomers comprises the following components in parts by weight:

[0061] First component: 20 to 50 parts of a compound having multiple isocyanate reactive functional groups. For example, it can be 20 parts, 30 parts, 40 parts, 50 parts, etc.

[0062] Second component: 10 to 40 parts of polyisocyanate compound. For example, it can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc.

[0063] The third component consists of 3 to 30 parts of (meth)acrylate monomers. For example, the amounts can be 3, 4, 5, 10, 15, 20, 25, or 30 parts.

[0064] Fourth component: 0.1 to 47 parts of polymerizable monomers. For example, it can be 0.1 parts, 0.3 parts, 1 part, 2 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 40 parts, 47 parts, etc.

[0065] Fifth component: 0.1 to 4 parts of photosensitizing initiator. For example, it can be 0.1, 0.2, 0.3, 0.5, 1, 1.5, 2.0, 2.5, 3.0, 3.5, or 4 parts.

[0066] Component 6: Chain transfer agent, 0.1 to 3 parts. For example, it can be 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.6 parts, 0.8 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, etc.

[0067] Component 7: Catalyst 0.1 to 3 parts. For example, it can be 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.6 parts, 0.8 parts, 1.0 parts, 1.5 parts, 2.0 parts, 2.2 parts, 2.5 parts, 2.8 parts, 3 parts, etc.

[0068] Component 8: Additives 0.1 to 7 parts. For example, it can be 0.1 parts, 0.2 parts, 0.3 parts, 0.5 parts, 1 part, 1.5 parts, 2.0 parts, 2.5 parts, 3.0 parts, 3.5 parts, 4 parts, 5 parts, 6 parts, 6.5 parts, 7 parts, etc.

[0069] As can be seen from the above, the photopolymer holographic recording medium containing (meth)acrylate monomers proposed in this application can achieve full synergistic effect of each component by reasonably controlling the amount of each component added. This prevents the holographic performance of the final photopolymer holographic recording medium from deteriorating due to too much or too little of a certain component, thus ensuring that the overall holographic performance of the final photopolymer holographic recording medium is better.

[0070] For example, by controlling the amount of compounds with multiple isocyanate reactive functional groups to 20 to 50 parts and the amount of polyisocyanate group compounds to 10 to 40 parts, the first component and the second component together form a film-forming resin with a low refractive index, thereby providing support for the other components.

[0071] By controlling the (meth)acrylate monomers to 3-30 parts and the polymerizable monomers to 0.1-47 parts, and the third and fourth components being the writing monomers, and considering that the intermolecular bonding refractive index will be higher after polymerization, the interaction of the above four components can achieve a high refractive index component and a low refractive index component with a large refractive index difference in the photopolymer holographic recording medium, forming a high refractive index difference between the film-forming resin and the writing monomer. Thus, under the action of light, the monomers in the bright area (such as the third and fourth components) polymerize and are consumed, resulting in a decrease in concentration, while the monomers in the dark area hardly react. The difference in monomer concentration between the bright and dark areas causes the high concentration of monomers in the dark area to begin migrating to the bright area, while the components of the film-forming resin in the bright area (such as the first and second components) are squeezed into the dark area, making the refractive index of the bright area close to the refractive index of the third and fourth components, while the refractive index of the dark area close to the refractive index of the first and second components, forming a phase-type volume holographic grating with refractive index modulation.

[0072] For example, by controlling the photoinitiator combination to 0.1 to 4 parts, an appropriate number of photons can be absorbed during exposure, and the polymerization reaction can be controlled at a certain speed, so that the grating can be formed quickly and obtain a high diffraction efficiency. In addition, it can also ensure that the final holographic recording medium has the required light transmittance and that the grating has a certain diffraction efficiency.

[0073] For example, by controlling the chain transfer agent to 0.1 to 3 parts, the polymer chain length can be controlled within a reasonable range, and the excessive polymerization can be effectively prevented, ensuring that the final holographic recording medium has the required optical properties and diffraction efficiency.

[0074] For example, controlling the catalyst to 0.1 to 3 parts can effectively increase the reaction rate of related components and the consumption rate of related components after exposure, thereby quickly forming a concentration difference of monomers in the bright and dark areas and realizing a phase-type volume holographic grating with refractive index modulation.

[0075] For example, by controlling the additive to 0.1 to 7 parts, and taking the additive as a leveling agent, the uniformity of the mixture can be effectively improved, the fluidity can be enhanced, and the cost can be reasonably controlled.

[0076] In some optional examples, a photopolymer-type holographic recording medium containing (meth)acrylate monomers comprises the following components in parts by weight: Component 1 – 23 parts of a compound having multiple isocyanate reactive functional groups; Component 2 – 23 parts of a polyisocyanate group compound; Component 3 – 30 parts of (meth)acrylate monomers; Component 4 – 18 parts of polymerizable monomers; Component 5 – 2 parts of a photoinitiator; Component 6 – 2 parts of a chain transfer agent; Component 7 – 0.7 parts of a catalyst; and Component 8 – 1.3 parts of an additive.

[0077] In some optional examples, a photopolymer-type holographic recording medium containing (meth)acrylate monomers comprises the following components in parts by weight: Component 1 – 20 parts of a compound having multiple isocyanate reactive functional groups; Component 2 – 40 parts of a polyisocyanate group compound; Component 3 – 3 parts of (meth)acrylate monomers; Component 4 – 20 parts of polymerizable monomers; Component 5 – 4 parts of a photoinitiator; Component 6 – 3 parts of a chain transfer agent; Component 7 – 3 parts of a catalyst; and Component 8 – 7 parts of additives.

[0078] In some optional examples, a photopolymer-type holographic recording medium containing (meth)acrylate monomers comprises the following components in parts by weight: Component 1 – 50 parts of a compound having multiple isocyanate reactive functional groups; Component 2 – 10 parts of a polyisocyanate group compound; Component 3 – 10 parts of (meth)acrylate monomers; Component 4 – 20 parts of polymerizable monomers; Component 5 – 2 parts of a photoinitiator combination; Component 6 – 1 part of a chain transfer agent; Component 7 – 2 parts of a catalyst; and Component 8 – 5 parts of additives.

[0079] In some optional examples, a photopolymer-type holographic recording medium containing (meth)acrylate monomers comprises the following components in parts by weight: Component 1 – 30 parts of a compound having multiple isocyanate reactive functional groups; Component 2 – 10 parts of a polyisocyanate group compound; Component 3 – 3 parts of (meth)acrylate monomers; Component 4 – 47 parts of polymerizable monomers; Component 5 – 4 parts of a photoinitiator combination; Component 6 – 1 part of a chain transfer agent; Component 7 – 3 parts of a catalyst; and Component 8 – 2 parts of additives.

[0080] In some optional examples, a photopolymer-type holographic recording medium containing (meth)acrylate monomers comprises the following components in parts by weight: Component 1 – 40 parts of a compound having multiple isocyanate reactive functional groups; Component 2 – 10 parts of a polyisocyanate group compound; Component 3 – 30 parts of (meth)acrylate monomers; Component 4 – 8.8 parts of polymerizable monomers; Component 5 – 4 parts of a photoinitiator; Component 6 – 0.1 parts of a chain transfer agent; Component 7 – 0.1 parts of a catalyst; and Component 8 – 7 parts of additives.

[0081] In some optional examples, a photopolymer-type holographic recording medium containing (meth)acrylate monomers comprises the following components in parts by weight: Component 1 – 30 parts of a compound having multiple isocyanate reactive functional groups; Component 2 – 20 parts of a polyisocyanate group compound; Component 3 – 30 parts of (meth)acrylate monomers; Component 4 – 10 parts of polymerizable monomers; Component 5 – 4 parts of a photoinitiator; Component 6 – 3 parts of a chain transfer agent; Component 7 – 0.5 parts of a catalyst; and Component 8 – 2.5 parts of an additive.

[0082] In some optional examples, a photopolymer-type holographic recording medium containing (meth)acrylate monomers comprises the following components in parts by weight: Component 1 – 30 parts of a compound having multiple isocyanate reactive functional groups; Component 2 – 30 parts of a polyisocyanate group compound; Component 3 – 20 parts of (meth)acrylate monomers; Component 4 – 10 parts of polymerizable monomers; Component 5 – 0.1 parts of a photoinitiator combination; Component 6 – 0.8 parts of a chain transfer agent; Component 7 – 2 parts of a catalyst; and Component 8 – 7 parts of additives.

[0083] In some optional examples, a photopolymer-type holographic recording medium containing (meth)acrylate monomers comprises the following components in parts by weight: Component 1 – 30 parts of a compound having multiple isocyanate reactive functional groups; Component 2 – 20 parts of a polyisocyanate group compound; Component 3 – 20 parts of (meth)acrylate monomers; Component 4 – 29.6 parts of polymerizable monomers; Component 5 – 0.1 parts of a photoinitiator combination; Component 6 – 0.1 parts of a chain transfer agent; Component 7 – 0.1 parts of a catalyst; and Component 8 – 0.1 parts of an additive.

[0084] In some examples of this application, in compounds having multiple isocyanate reactive functional groups, the isocyanate reactive functional group is a hydroxyl group. The hydroxyl group is a polar group, and the alcoholic hydroxyl group is easily oxidized, exhibiting high reactivity.

[0085] More specifically, the compound having multiple isocyanate reactive functional groups is selected from at least one of tetraethylene glycol, trimethylolethane, glycerol, triethanolamine, polyester polyols with a molecular weight of 200 to 2000, polycarbonate polyols, and polyether polyols. In some examples, the compound having multiple isocyanate reactive functional groups has a refractive index of less than 1.5.

[0086] In some examples of this application, the polyisocyanate compound is a compound having two or more isocyanate groups.

[0087] In specific examples, the polyisocyanate-based compound is selected from at least one of hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl)tri(hexamethylene)isocyanate, butane-1,4-diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate. In some examples, the refractive index of the polyisocyanate-based compound is less than 1.5.

[0088] In some examples of this application, the polymerizable monomer is selected from at least one of alkenylnaphthalene compounds, alkenylanthracene compounds, alkenylbenzene compounds, acrylic compounds, methacrylic acid compounds, acrylate compounds, methacrylate compounds, N-vinylpyrrole, N-vinylcarbazole, N-vinylimidazol, N-vinylindole, N-vinylpyrrolidone, and trans-N-3-yntynebutenylcarbazole.

[0089] In a specific example, the alkenylnaphthalene compound is selected from at least one of 1-vinylnaphthalene and 2-vinylnaphthalene.

[0090] In a specific example, the alkenyl anthracene compound is selected from at least one of 2-vinylanthracene and 9-vinylanthracene.

[0091] In a specific example, the alkenylbenzene compound is selected from at least one of styrene, 2-chlorostyrene, 2-bromostyrene, 3-chlorostyrene, 3-bromostyrene, 4-chlorostyrene, 4-bromostyrene, p-(chloromethyl)styrene, and p-(bromomethyl)styrene.

[0092] In specific examples, methacrylic acid compounds include at least one of methacrylic acid and its derivatives.

[0093] In specific examples, the acrylate compound is selected from at least one of pentabromophenyl acrylate, pentachlorophenyl acrylate, phenoxyethyl acrylate, pentabromobenzyl acrylate, 2-naphthyl acrylate, 1,4-di(2-thionaphthyl)2-butyl acrylate, phenoxyethoxyethyl acrylate, bisphenol A diacrylate, tetrabromobisphenol A diacrylate, 2-phenoxyethyl acrylate, benzyl acrylate, p-chlorophenyl acrylate, 2,4,6-trichlorophenyl acrylate, p-bromophenyl acrylate, 2,4,6-tribromophenyl acrylate, propane-2,2-diylbis[(2,6-dibromo-4,1-phenylene)oxy(2-{[3,3,3-tris(4-chlorophenyl)propionyl]oxy}propane-3,1-diyl)oxyethane-2,1-diyl]diacrylate.

[0094] In specific examples, the methacrylate compounds are selected from at least one of 2-phenoxyethyl methacrylate, benzyl methacrylate, p-bromophenyl methacrylate, p-chlorophenyl methacrylate, 2,4,6-trichlorophenyl methacrylate, pentabromophenyl methacrylate, pentachlorophenyl methacrylate, phenoxyethyl methacrylate, phenoxyethoxyethyl methacrylate, 1,4-di(2-thionaphthyl)2-butyl methacrylate, pentabromobenzyl methacrylate, 2-naphthyl methacrylate, bisphenol A dimethacrylate, and tetrabromobisphenol A dimethacrylate.

[0095] In some examples of this application, the photoinitiator combination includes a photosensitizer and a photoinitiator. The photosensitizer, when combined with the photoinitiator, can form a visible light initiation system compatible with lasers of different wavelengths. Under irradiation with light within a specific wavelength range, the photosensitizer in the photoinitiation system is activated accordingly, absorbs light energy, and transfers the light energy to the photoinitiator. This allows the photoinitiator to be activated under light radiation of more frequencies, generating free radicals with initiation functions. These photoinitiated free radicals can initiate monomer polymerization to construct holographic gratings, improve the photosensitivity of photopolymer-based holographic recording media, and broaden the range of selectable light sources.

[0096] Therefore, it is understandable that in other examples, when this application uses a photoinitiator with an appropriate wavelength, a photosensitizer may not be added.

[0097] When the photoinitiator combination contains both a photosensitizer and a photoinitiator, the mass ratio of the photosensitizer to the photoinitiator is further (0.001–1):(0.1–3). By controlling the mass ratio of the photosensitizer to the photoinitiator within the above range, the concentration of the photosensitizer can be effectively controlled, ensuring that the number of absorbed photons during holographic exposure is controlled within a suitable range, the polymerization reaction rate is controlled within a reasonable range, and the grating formation rate is controlled within a certain range, thus guaranteeing the transmittance of the photopolymer holographic recording medium and obtaining excellent diffraction efficiency. In more specific examples, the mass of the photosensitizer is 1 / 10 to 1 / 3 of the mass of the photoinitiator, such as 1 / 10, 1 / 9, 1 / 8, 1 / 7, 1 / 6, 1 / 5, 1 / 4, or 1 / 3, etc.

[0098] In this application, different broadband responses can be achieved by adjusting the type of photosensitizer. For example, the photosensitizer is a dye with high electron transfer efficiency under light irradiation.

[0099] In a specific example, the photosensitizer is selected from at least one of cyanine dyes, fluorescein dyes, coumarin ketone dyes, nitrogen-containing aromatic heterocyclic compounds, aromatic amine compounds, and benzylidene cycloalkane ketone compounds.

[0100] More specifically, the photosensitizer is selected from one or more of the following: neomethylene blue, thionine, basic yellow, pinacyanin chloride, rhodamine 6G, gallium cyanide, ethyl violet, Victoria blue R, celestite blue, methylene blue, basic orange, darone red, pyrrole red Y, basic red 29, quinaldinium red, crystal violet, ethyl violet, brilliant green, azure A, crystal violet cyanonitrile, and malachite green cyanonitrile.

[0101] In specific examples, the photoinitiator is selected from at least one of aromatic ketone compounds, benzoin and its derivatives, benzoyl ketal, acylphosphine oxide, ammonium arylboronate, chromium salts, aryl diazonium salts, onium salts, and organometallic compounds. Other photoinitiators with similar functions may also be used, and this application does not impose any limitations.

[0102] More specifically, the photoinitiator is selected from one or more of the following: benzophenone, alkylbenzophenone, 4,4'-di(dimethylamino)benzophenone, anthrone and halogenated benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, diacylphosphine oxide, phenyl dihydroxyacetate, camphorquinone, α-aminoalkylphenyl ketone, α,α-dialkoxyacetophenone, α-hydroxyalkylphenyl ketone, tetrabutylammonium triphenylhexylborate, tetrabutylammonium tri-(3-fluorophenyl)hexylborate, tetrabutylammonium tri-(3-chloro-4-methylphenyl)hexylborate, ferrocene compounds, iodonium salts, thiodonium salts, and hexaaryldiimidazole. When these photoinitiators are irradiated with light within the corresponding wavelength range, they can be rapidly activated and generate active free radicals, thereby initiating polymerization reactions between the components of the photopolymer-type holographic recording medium, achieving monomer concentration differences between bright and dark areas.

[0103] In some examples of this application, the chain transfer agent is a thiol compound.

[0104] In a specific example, the chain transfer agent is selected from one or more of dodecyl mercaptoethanol, hexamethylene mercaptoethanol, phenylethyl mercaptoethanol, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, and 4-methyl-4H-1,2,4-triazole-3-thiol.

[0105] In some examples of this application, the catalyst is a tertiary amine catalyst or an organometallic catalyst.

[0106] In a specific example, the catalyst is selected from at least one of triethylenediamine, bis(dimethylaminoethyl) ether, dimethylethanolamine, 2-(2-dimethylaminoethoxy)ethanol, trimethylhydroxyethylpropanediamine, N,N-bis(dimethylaminopropyl)isopropanolamine, dibutyltin dilaurate, stannous octoate, potassium carboxylate catalysts, and bismuth carboxylate catalysts.

[0107] In some examples of this application, the additives include one or more of defoamers, leveling agents, and plasticizers.

[0108] In a specific example, the defoamer is a silicone defoamer and / or a silicone-free polymeric defoamer, and the defoamer accounts for less than or equal to 3% of the weight of the photopolymeric holographic recording medium. The defoamer can reduce the surface tension of the liquid and remove foam, thereby improving the flowability of the mixture of components.

[0109] More specifically, one can choose, for example, BYK-011, BYK-012, BYK-014, BYK-023, BYK-051N, BYK-085, BYK-1610, BYK-1707, BYK-1740, and BYK-1760 manufactured by BYK Corporation, or DC65 and AFE-7820 manufactured by Dow Corning Corporation, or any mixture of these defoamers in any proportion. The BYK series of defoamers have excellent defoaming performance, good compatibility with other components, and good dispersibility; among them, BYK-011, BYK-012, BYK-014, and BYK-051N are silicone-free polymeric defoamers. DC65 is a water-based ink that dries quickly, provides good printing results, and is not easily peeled off. AFE-7820 has highly efficient defoaming performance.

[0110] In a specific example, the leveling agent is a silicone surface additive, and the leveling agent accounts for less than or equal to 3% by weight of the photopolymer-type holographic recording medium. Examples include BYK-302, BYK-306, BYK-307, BYK-327, BYK-329, BYK-333, BYK-356, BYK-358, BYK-378, BYK-3455, BYK-3566, or any mixture of these surface additives manufactured by BYK. The BYK series of leveling agents exhibits excellent leveling properties.

[0111] In a specific example, the plasticizer is selected from at least one of toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, and phthalates, and the plasticizer accounts for less than or equal to 3% by weight of the photopolymer-type holographic recording medium. The plasticizer increases the plasticity of the polymer by intercalating between polymer molecular chains, weakening the intermolecular stress, increasing the mobility of molecular chains, and reducing crystallinity.

[0112] In other examples of this application, the additive includes a dehydrating agent, and the dehydrating agent accounts for less than or equal to 3% by weight of the photopolymer-type holographic recording medium. The dehydrating agent can remove excess water during the reaction, allowing the components to mix better and preventing stratification.

[0113] In specific examples, the dehydrating agents are selected from methylbenzenesulfonyl isocyanate, triethyl orthoformate, CUWR-WB20 dehydrating agent from Guangzhou Yourun Synthetic Materials Co., Ltd., ALT-201 dehydrating agent from Anxiang Elite Chemical Co., Ltd., and PCCI dehydrating agent from Shanghai Luer Chemical Trading Co., Ltd., etc.

[0114] The application of the aforementioned photopolymer holographic recording medium described below.

[0115] The holographic optical element proposed in this application is made of photopolymer-type holographic recording media as described in the foregoing examples. This holographic optical element includes, but is not limited to, volume holographic gratings.

[0116] As can be seen from the above, the holographic optical element proposed in this application, since it includes the aforementioned photopolymer holographic recording medium, also has the advantages of the photopolymer holographic recording medium of this application, and has excellent holographic performance, high diffraction efficiency, high sensitivity, and low required exposure amount.

[0117] The optical device proposed in this application includes holographic optical elements as described above. This optical device includes, but is not limited to, head-up displays (HUDs), augmented reality (AR) devices, virtual reality (VR) devices, and photopolymer holographic storage optical discs. Photopolymer holographic storage optical discs can be erasable and rewritable, and can record in real time, making them suitable for storing large amounts of data with very fast data transfer speeds.

[0118] As can be seen from the above, the optical device proposed in this application, since it includes the aforementioned holographic optical element, also has the advantages of the holographic optical element in this application. The optical device has excellent holographic performance, clear image, and can store a large amount of data.

[0119] The following describes the (meth)acrylate monomers, the preparation method of the (meth)acrylate monomers, and the photopolymer holographic recording medium containing (meth)acrylate monomers in this application with reference to specific embodiments.

[0120] Example 1

[0121] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-a: In this example, the monomer is a (meth)acrylate with the general structural formula G1, where R1, R2, and R3 are all hydrogen atoms.

[0122] Referring to Figure 1, the preparation method of (meth)acrylate monomers with structural formula G1-a is as follows: The monomers with structural formula G1-a are prepared by... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as ethanol at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as triethylenediamine was added and the reaction was carried out for 5 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate the (meth)acrylate monomer with the structural formula G1-a, which has a refractive index of 1.57. The characterization data are as follows:

[0123] 1 H NMR (400MHz, CDCl3) δ8.18(s,1H),7.28-7.38(m,5H),6.41(dd,1H),6.12(dd,1H),5.83(dd,1H),4.58(t,2H),3.13(t,2H).

[0124] 13 C NMR (101MHz, CDCl3) δ167.3,166.5,135.1,131.3,129.4,129.0,128.2,125.5,67.2,41.4.

[0125] Example 2

[0126] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-b: In this example, the monomer is a (meth)acrylate with the general structural formula G1, R2 is -S-CH3, and R1 and R3 are hydrogen.

[0127] Please refer to Figure 2. The preparation method of (meth)acrylate monomers with structural formula G1-b is as follows: [The following text appears to be a separate, unrelated section:] ...[The text continues with a description of a process involving the preparation of (meth)acrylate monomers with structural formula G1-b... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as petroleum ether at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as bis(dimethylaminoethyl) ether was added and the reaction was carried out for 3 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate the (meth)acrylate monomer with the structural formula G1-b, which has a refractive index of 1.60. The characterization data are as follows:

[0128] 1 H NMR (400MHz, CDCl3) δ8.18(s,1H),7.26(d,2H),7.20(d,2H),6.41(dd,1H),6.12(dd,1H),5.83(dd,1H),4.58(t,2H),3.15(t,2H),2.38(s,3H).

[0129] 13C NMR (101MHz, CDCl3) δ167.3,166.5,135.1,136.2,131.5,129.6,128.2,125.5,67.2,41.4,14.8.

[0130] Example 3

[0131] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-c: In this example, it is a (meth)acrylate monomer with the general structural formula G1, and R2 is... Furthermore, A1 is a phenyl group, and R1 and R3 are hydrogen atoms.

[0132] Please refer to Figure 3. The preparation method of (meth)acrylate monomers with structural formula G1-c is as follows: [The following text appears to be a separate, unrelated section:] ...[The text continues with a description of a process involving the preparation of (meth)acrylate monomers with structural formula G1-c... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as dichloromethane at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as dimethylethanolamine was added and the reaction was carried out for 6 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate the (meth)acrylate monomer with the structural formula G1-c, which had a refractive index of 1.63. The characterization data are as follows:

[0133] 1 H NMR (400MHz, CDCl3) δ8.18(s,1H),7.40-44(m,5H),7.22(d,2H),7.16(d,2H),6.41(dd,1H),6.12(dd,1H),5.83(dd,1H),4.58(t,2H),3.15(t,2H). 13 C NMR (101MHz, CDCl3) δ167.3,166.5,135.7,133.6,132.5,131.5,131.2,129.3,128.2,127.2,67.2,41.4.

[0134] Example 4

[0135] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-d: In this example, it is a (meth)acrylate monomer with the general structural formula G1, where R1 is hydrogen, R2 is hydrogen, and R3 is methyl in the meta position of S.

[0136] Please refer to Figure 4. The preparation method of (meth)acrylate monomers with structural formula G1-d is as follows: The monomers with structural formula G1-d are prepared by... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as chloroform at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as 2-(2-dimethylamino-ethoxy)ethanol was added and the reaction was carried out for 2 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate the (meth)acrylate monomer with the structural formula G1-d, which had a refractive index of 1.57. The characterization data are as follows:

[0137] 1 H NMR(400MHz, CDCl3)δ8.18(s,1H),7.28(m,1H),7.11-7.14(m,2H),6.86(d,1H),6 .41(dd,1H),6.12(dd,1H),5.83(dd,1H),4.58(t,2H),3.15(t,2H),2.36(s,3H).

[0138] 13 C NMR (101MHz, CDCl3) δ167.3,166.5,140.7,135.0,136.1,131.3,128.9,128.2,126.4,125.8,67.2,41.4,21.3.

[0139] Example 5

[0140] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-e: In this example, it is a (meth)acrylate monomer with the general structural formula G1, where R1 and R2 are hydrogen atoms, and R3 is a methyl group at the para position of S.

[0141] Please refer to Figure 5. The preparation method of (meth)acrylate monomers with structural formula G1-e is as follows: [The following text appears to be a separate, unrelated section:] ...[The text appears to be a separate, unrelated section:] ... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as ethyl acetate at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as trimethylhydroxyethylpropanediamine was added and the reaction was carried out for 1 hour. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate the (meth)acrylate monomer with the structural formula G1-e, which has a refractive index of 1.57. The characterization data are as follows:

[0142] 1 H NMR (400MHz, CDCl3) δ8.18(s,1H),6.80(d,2H),6.71(d,2H),6.41(dd,1H),6.12(dd,1H),5.83(dd,1H),4.58(t,2H),3.15(t,2H),2.32(s,3H).

[0143] 13C NMR (101MHz, CDCl3) δ167.3,166.5,137.9,132.1,131.3,129.3,128.2,67.2,41.4,21.3.

[0144] Example 6

[0145] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-f: In this example, it is a (meth)acrylate monomer with the general structural formula G1, where R1 and R2 are hydrogen, and R3 is bromine in the meta position of S.

[0146] Please refer to Figure 6. The preparation method of (meth)acrylate monomers with structural formula G1-f is as follows: [The following text appears to be a separate, unrelated section:] ...[The text appears to be a separate, unrelated section:] ... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as dichloromethane at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as dibutyltin dilaurate was added and the reaction was carried out for 2 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate the (meth)acrylate monomer with the structural formula G1-f, which has a refractive index of 1.58. The characterization data are as follows:

[0147] 1 H NMR (400MHz, CDCl3) δ8.18(s,1H),7.32-7.35(m,3H),7.08(t,1H),6.41(dd,1H),6.12(dd,1H),5.83(dd,1H),4.58(t,2H),3.15(t,2H).

[0148] 13 C NMR (101MHz, CDCl3) δ169.1,166.5,137.3,133.0,131.3,129.9,128.4,128.2,127.5,67.2,14.2.

[0149] Example 7

[0150] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-g: In this example, it is a (meth)acrylate monomer with the general structural formula G1, where R1 and R2 are hydrogens, and R3 is a methyl group in the ortho position of sulfur.

[0151] Please refer to Figure 7. The preparation method of (meth)acrylate monomers with structural formula G1-g is as follows: [The following text appears to be a separate, unrelated section:] ...[The text appears to be a separate, unrelated section:] ... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as toluene at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as dibutyltin dilaurate was added and the reaction was carried out for 0.5 h. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate the (meth)acrylate monomer with the structural formula G1-g, which had a refractive index of 1.57. The characterization data are as follows:

[0152] 1 H NMR(400MHz, CDCl3)δ8.18(s,1H),7.49(d,2H),7.31(d,1H),7.31(m,1H),6.4 1(dd,1H),6.12(dd,1H),5.83(dd,1H),4.58(t,2H),3.15(t,2H),2.34(s,3H).

[0153] 13 C NMR (101MHz, CDCl3) δ167.3,166.5,142.0,133.6,131.3,131.1,128.2,127.0,126.0,125.4,67.2,41.1,21.7.

[0154] Example 8

[0155] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-h: In this example, the monomer is a (meth)acrylate with the general structural formula G1, where R1 is hydrogen, R2 is methyl, and R3 is methyl, and both are located at two adjacent positions to sulfur.

[0156] Please refer to Figure 8. The preparation method of (meth)acrylate monomers with structural formula G1-h is as follows: The monomers with structural formula G1-h are prepared by... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as acetonitrile at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as stannous octoate was added and the reaction was carried out for 10 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate the (meth)acrylate monomer with the structural formula G1-h, which had a refractive index of 1.57. The characterization data are as follows:

[0157] 1 H NMR (400MHz, CDCl3) δ8.18(s,1H),7.39(d,2H),7.21(d,1H),6.41(dd,1H),6.12(dd,1H),5.83(dd,1H),4.58(t,2H),3.15(t,2H),2.34(s,6H).

[0158] 13C NMR (101MHz, CDCl3) δ167.3,166.5,141.9,133.9,131.3,128.2,128.1,125.3,67.2,41.1,22.0.

[0159] Example 9

[0160] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-i: In this example, the monomer is a (meth)acrylate with the general structural formula G1, where R1 is methyl, R2 is a phenyl group at the para-position of S, and R3 is hydrogen.

[0161] Please refer to Figure 9. The preparation method of (meth)acrylate monomers with structural formula G1-i is as follows: [The following text appears to be a separate, unrelated section:] ...[The text appears to be a separate, unrelated section:] ... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as N,N-dimethylformamide at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as potassium carboxylate was added and the reaction was carried out for 9 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate the (meth)acrylate monomer with the structural formula G1-i, which has a refractive index of 1.59. The characterization data are as follows:

[0162] 1 H NMR (400MHz, CDCl3) δ8.18(s,1H),7.75(d,2H),7.41-7.61(m,7H),6.48(d,1H),6.40(d,1H),4.58(t,2H),3.15(t,2H),2.01(s,3H).

[0163] 13 C NMR (101MHz, CDCl3) δ167.3,167.2,140.9,137.6,136.0,134.0,129.9,129.2,128.2,127.9,127.6,125.2,67.6,41.1,17.9.

[0164] Example 10

[0165] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-j: In this example, the monomer is a (meth)acrylate with the general structural formula G1, where R1 is methyl, R2 is the para-methyl group at the S position, and R3 is the ortho-methyl group at the S position.

[0166] Referring to Figure 10, the preparation method of (meth)acrylate monomers with structural formula G1-j is as follows: The monomers with structural formula G1-j are prepared by... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as dimethyl sulfoxide at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as a bismuth carboxylic acid catalyst was added and reacted for 6 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate the (meth)acrylate monomer with the structural formula G1-j, which has a refractive index of 1.57. The characterization data are as follows:

[0167] 1 H NMR(400MHz, CDCl3)δ8.18(s,1H),7.26(d,1H),6.93(d,1H),6.91(s,1H),6.48(d, 1H),6.40(d,1H),4.58(t,2H),3.15(t,2H),2.31(s,3H),2.34(s,3H),2.01(s,3H).

[0168] 13 C NMR (101MHz, CDCl3) δ167.3,167.2,141.9,135.1,136.0,131.2,130.6,129.2,126.3,125.2,67.6,41.1,22.0,21.6,17.9.

[0169] Example 11

[0170] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-k: In this example, the monomer is a (meth)acrylate with the general structural formula G1, where R1 is a methyl group, and R2 and R3 are methyl groups located at two meta positions in S.

[0171] Referring to Figure 11, the preparation method of (meth)acrylate monomers with structural formula G1-k is as follows: The monomers with structural formula G1-k are prepared by... The compound P1 and its structural formula are Compound P2 was added sequentially to solvents such as ethanol and acetonitrile in a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as 2-(2-dimethylamino-ethoxy)ethanol was added and the reaction was carried out for 4 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate (meth)acrylate monomers with the structural formula G1-k, which had a refractive index of 1.57. The characterization data are as follows:

[0172] 1 H NMR (400MHz, CDCl3) δ8.18(s,1H),7.01(s,3H),6.48(d,1H),6.40(d,1H),4.58(t,2H),3.15(t,2H),2.35(s,6H),2.01(s,3H).

[0173] 13 C NMR (101MHz, CDCl3) δ167.3,167.2,136.0,134.9,133.1,125.2,123.8,67.6,41.1,21.6,17.9.

[0174] Example 12

[0175] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-l: In this example, it is a (meth)acrylate monomer with the general structural formula G1, where R1 is methyl, R2 is hydrogen, and R3 is bromine at the para position of S.

[0176] Please refer to Figure 12. The preparation method of (meth)acrylate monomers with structural formula G1-l is as follows: The monomers with structural formula G1-l are prepared by... The compound P1 and its structural formula are Compound P2 was added sequentially to solvents such as ethanol and toluene in a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as 2-(2-dimethylamino-ethoxy)ethanol was added and the reaction was carried out for 5 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate the (meth)acrylate monomer with the structural formula G1-l. Its refractive index was 1.59. The characterization data are as follows:

[0177] 1 H NMR (400MHz, CDCl3) δ8.18(s,1H),7.75(d,2H),7.25(d,2H),6.48(d,1H),6.40(d,1H),4.58(t,2H),3.15(t,2H),2.01(s,3H).

[0178] 13 C NMR (101MHz, CDCl3) δ167.3,167.2,136.0,134.1,131.9,131.6,125.2,119.9,67.5,41.1,17.9.

[0179] Example 13

[0180] In this embodiment, the structural formula of the (meth)acrylate monomer is G1-m: In this example, it is a (meth)acrylate monomer with the general structural formula G1, where R1 is methyl, R2 is hydrogen, and R3 is bromine in the ortho position of S.

[0181] Referring to Figure 13, the preparation method of (meth)acrylate monomers with the structural formula G1-m is as follows: The monomers with the structural formula G1-m are prepared as follows: The compound P1 and its structural formula are Compound P2 was added sequentially to solvents such as ethanol and dimethyl sulfoxide in a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as dimethylethanolamine was added and the reaction was carried out for 7 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate (meth)acrylate monomers with the structural formula G1-m and a refractive index of 1.58. The characterization data are as follows:

[0182] 1 H NMR (400MHz, CDCl3) δ8.18(s,1H),7.38(d,1H),7.20-7.25(m,3H),6.48(d,1H),6.40(d,1H),4.58(t,2H),3.15(t,2H),2.01(s,3H).

[0183] 13 C NMR (101MHz, CDCl3) δ167.3,167.2,136.0,135.8,131.9,131.6,128.0,127.7,125.2,121.2,67.5,41.1,17.9.

[0184] Example 14

[0185] In this embodiment, the structural formula of the (meth)acrylate monomer is G2-a: In this example, it is a (meth)acrylate monomer with the general structural formula G2, where R1 is methyl.

[0186] Referring to Figure 14, the preparation method of (meth)acrylate monomers with structural formula G2-a is as follows: The monomers with structural formula G2-a are prepared by... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as tetrahydrofuran at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as N,N-bis(dimethylaminopropyl)isopropanolamine was added and the reaction was carried out for 9 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate a (meth)acrylate monomer with the structural formula G2-a, which has a refractive index of 1.60. The characterization data are as follows:

[0187] 1 H NMR(400MHz, CDCl3)δ8.18(s,1H),7.96(dd,1H),7.79-7.84(m,2H),7.70(d,1H),7 .48-7.50(m,3H),6.48(d,1H),6.40(d,1H),4.58(t,2H),3.15(t,2H),2.01(s,3H).

[0188] 13C NMR (101MHz, CDCl3) δ167.3,167.2,136.0,134.1,131.1,130.6,129.9,128.4,128.1,126.6,126.2,125.2,67.5,41.1,17.9.

[0189] Example 15

[0190] In this embodiment, the structural formula of the (meth)acrylate monomer is G3-a: In this example, it is a (meth)acrylate monomer with the general structural formula G3, where R1 is methyl.

[0191] Please refer to Figure 15. The preparation method of (meth)acrylate monomers with structural formula G3-a is as follows: [The following text appears to be a separate, unrelated section:] ...[The text appears to be a separate, unrelated section:] ... The compound P1 and its structural formula are Compound P2 was added sequentially to a solvent such as toluene at a molar ratio of 1:1. After stirring until homogeneous, a catalyst such as dimethylethanolamine was added and the reaction was carried out for 6 hours. After the reaction was completed, excess solvent was removed by rotary evaporation, and column chromatography was used to separate a (meth)acrylate monomer with the structural formula G3-a and a refractive index of 1.60. The characterization data are as follows:

[0192] 1 H NMR (400MHz, CDCl3) δ8.12-8.18(m,3H),7.93(d,1H),7.40-7.59(m,4H),6.48(d,1H),6.40(d,1H),4.58(t,2H),3.15(t,2H),2.01(s,3H).

[0193] 13 C NMR (101MHz, CDCl3) δ167.3,167.2,136.0,134.1,132.0,129.8,128.7,128.3,126.6,126.2,125.2,125.1,67.5,41.1,17.9.

[0194] The solvents and catalysts used in the foregoing embodiments are for illustrative purposes only. The solvents may be one or more of ethanol, petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, toluene, acetonitrile, N,N-dimethylformamide, or dimethyl sulfoxide. The catalysts may be one or more of triethylenediamine, bis(dimethylaminoethyl) ether, dimethylethanolamine, 2-(2-dimethylaminoethoxy)ethanol, trimethylhydroxyethylpropanediamine, N,N-bis(dimethylaminopropyl)isopropanolamine, dibutyltin dilaurate, stannous octoate, potassium carboxylate catalysts, and bismuth carboxylate catalysts, all of which should be within the scope of protection of this application.

[0195] Example 16

[0196] Photopolymer holographic recording media 1-1 to 1-13 containing (meth)acrylate monomers from Examples 1-13 are used: The specific components of photopolymer holographic recording media 1-1 to 1-13 are shown in Table 1 below.

[0197] Table 1. Components of each photopolymer-based holographic recording medium in Example 16

[0198] In this embodiment, the selection of each component may also be other components listed above. These embodiments should not be construed as limiting the scope of protection of this application.

[0199] Example 17

[0200] The composition is largely the same as that of the photopolymer holographic recording medium 1-1 in Example 16, except that 0.3 parts of basic yellow are used as the photosensitizer, and the (meth)acrylate monomer with structural formula G1-a in Example 16 is replaced with the (meth)acrylate monomer with structural formula G2-a in Example 14, thereby forming the photopolymer holographic recording medium 2-1 containing the (meth)acrylate monomer of Example 14.

[0201] Example 18

[0202] The composition is largely the same as that of the photopolymer holographic recording medium 1-1 in Example 16, except that 0.3 parts of eosin are used as the photosensitizer, and the (meth)acrylate monomer with structural formula G1-a in Example 16 is replaced with the (meth)acrylate monomer with structural formula G3-a in Example 15, thereby forming the photopolymer holographic recording medium 3-1 containing the (meth)acrylate monomer of Example 15.

[0203] Comparative Example

[0204] The composition is roughly the same as that of the photopolymer holographic recording medium of Example 16, except that the (meth)acrylate monomers of Example 16 are removed, so that the number of (meth)acrylate monomers becomes 0 parts, and the polymerizable monomers are increased to 55 parts, thus obtaining a common photopolymer holographic recording medium.

[0205] Test case

[0206] The performance of the holographic recording media in Examples 16-18 and the comparative examples was tested. During the tests, different wavelengths of laser light were selected for exposure in Examples 16, 17, and 18, depending on the photosensitive system, with an exposure light intensity of 3 mW / cm². 2 The exposure wavelength of the photopolymer holographic recording medium 1-1 is 633nm, the exposure wavelength of the photopolymer holographic recording medium 2-1 in the embodiment is 457nm, and the exposure wavelength of the photopolymer holographic recording medium 3-1 is 532nm.

[0207] The testing method includes the following steps:

[0208] Solid-state lasers with wavelengths of 633nm, 457nm, and 532nm were used as light sources. After passing through a beam expander, beam splitter, and half-wave plate, two beams with the same intensity and a diameter of 8mm were obtained. The two beams were intersected and exposed within the prepared holographic recording medium at an intensity of 3mW / cm². 2 The detection light source uses a 785nm wavelength solid-state laser that does not react with the recording medium. The detection light is incident on the exposure area from the Bragg angle. The transmitted light and diffracted light are monitored in real time by a photodetector. The single grating diffraction efficiency (η) and photosensitivity (S) of the photopolymer holographic recording medium are calculated by formulas (1) to (3).

[0209] In the formula, η is the diffraction efficiency, η max For the highest diffraction efficiency, I d For diffracted light, I t S represents transmitted light, S represents photosensitivity, E represents exposure energy, and ΔE represents the exposure energy required to achieve the highest diffraction efficiency.

[0210] The holographic performance tests of the photopolymer holographic recording media 1-1 to 1-13 in Example 16, the photopolymer holographic recording media 2-1 in Example 17, the photopolymer holographic recording media 3-1 in Example 18, and the ordinary photopolymer holographic recording media of the comparative example are shown in Table 2 below.

[0211] Table 2. Holographic performance test table of each photopolymer holographic recording medium in Examples 16-18 and Comparative Examples.

[0212] Holographic performance tests were performed on the photopolymer holographic recording media 1-1 to 1-13 containing (meth)acrylate monomers in Example 16, the photopolymer holographic recording media 2-1 in Example 17, the photopolymer holographic recording media 3-1 in Example 18, and the ordinary photopolymer holographic recording media in the comparative examples.

[0213] Figure 16 shows the holographic performance diagrams plotted using the photopolymer holographic recording medium 1-1 from Example 16, the photopolymer holographic recording medium 2-1 from Example 17, and the photopolymer holographic recording medium 3-1 from Example 18. The final measured diffraction efficiency of the photopolymer holographic recording medium of this application is greater than 95%, and the exposure dose is less than 20 mJ / cm². 2 Sensitivity greater than 100cm 2 / mJ.

[0214] As shown in Figure 17, a conventional photopolymer holographic recording medium for comparison was exposed at a wavelength of 633 nm and an exposure intensity of 3 mW / cm². 2 The diffraction efficiency of the ordinary photopolymer holographic recording medium in the comparative example was found to be less than 50%, requiring an exposure dose greater than 100 mJ / cm². 2 The sensitivity is low.

[0215] In summary, referring to Figures 16 and 17 and Table 2, the photopolymer holographic recording medium of this application has a much higher diffraction efficiency and sensitivity than the comparative example, and requires less exposure.

[0216] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A (meth)acrylate monomer, wherein, The structural general formula is shown as formula G1, G2 and G3: wherein R1is methyl or hydrogen; R2, R3are selected from hydrogen, Br, phenyl, methyl or wherein A1 in the formula represents either phenyl or methyl.

2. The (meth)acrylate monomer as described in claim 1, wherein, The (meth)acrylate monomer is selected from monomers having the following structural formula: wherein R1is methyl or hydrogen.

3. The (meth)acrylate monomer according to claim 1, wherein The (meth)acrylate monomer has a refractive index of 1.54 to 1.62 and a kinematic viscosity of 5 mm 2 / s to 20 mm 2 / s.

4. A process for producing the (meth)acrylate monomer as claimed in any one of claims 1 to 3, wherein, Compounds P1 and P2 were added to the solvent in a molar ratio of 1:1, stirred until homogeneous, and then a catalyst was added and reacted for 0.5 h to 10 h. After the reaction was completed, excess solvent was removed by rotary evaporation, and (meth)acrylate monomers were obtained by column chromatography. wherein the structural formula of the compound P1 is as follows: R2 and R3 are selected from hydrogen, Br, phenyl, and methyl. A1 in the formula is phenyl or methyl; the structural formula of compound P2 is R1 can be either methyl or hydrogen.

5. The method for preparing (meth)acrylate monomers as described in claim 4, wherein, The compound P1 is selected from compounds having the following structural formula:

6. The method of preparing a (meth)acrylate monomer according to claim 4, wherein The solvent is selected from one or more of ethanol, petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, toluene, acetonitrile, N,N-dimethylformamide, or dimethyl sulfoxide; and / or, The catalyst is a tertiary amine catalyst or an organometallic catalyst.

7. The method of preparing a (meth)acrylate monomer according to claim 6, wherein The catalyst is selected from one or more of the following: triethylenediamine, bis(dimethylaminoethyl) ether, dimethylethanolamine, 2-(2-dimethylaminoethoxy)ethanol, trimethylhydroxyethylpropanediamine, N,N-bis(dimethylaminopropyl)isopropanolamine, dibutyltin dilaurate, stannous octoate, potassium carboxylate catalysts, and bismuth carboxylate catalysts.

8. A photopolymer-type holographic recording medium containing a (meth)acrylate monomer as described in any one of claims 1 to 3, wherein, It includes writing monomers, which include the (meth)acrylate monomers and polymerizable monomers.

9. The photopolymer type holographic recording medium according to claim 8, wherein, The components include the following parts by weight: First component: 20 to 50 parts of a compound having multiple isocyanate reactive functional groups; Second component: 10 to 40 parts of polyisocyanate group compound; Third component: (meth)acrylate monomers, 3 to 30 parts; Fourth component: 0.1 to 47 parts of polymerizable monomer; Fifth component: 0.1 to 4 parts of photosensitizing initiator; Component 6: Chain transfer agent 0.1 to 3 parts; Component 7: Catalyst 0.1 to 3 parts; Component 8: 0.1 to 7 parts of additives.

10. The photopolymer type holographic recording medium according to claim 9, wherein, In the compound having multiple isocyanate reactive functional groups, the isocyanate reactive functional group is a hydroxyl group; The polyisocyanate compound is a compound having two or more isocyanate groups.

11. The photopolymer type holographic recording medium according to claim 10, wherein, The polyisocyanate compound is selected from at least one of hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl)tris(hexamethylene)isocyanate, butane-1,4-diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate; or... The refractive index of the polyisocyanate-based compound is less than 1.

5.

12. The photopolymer type holographic recording medium according to claim 8 or 9, wherein, The polymerizable monomer is selected from at least one of alkenylnaphthalene compounds, alkenylanthracene compounds, alkenylbenzene compounds, acrylic acid compounds, methacrylic acid compounds, acrylate compounds, methacrylate compounds, N-vinylpyrrole, N-vinylcarbazole, N-vinylimidazol, N-vinylindole, N-vinylpyrrolidone, and trans-N-3-yntynebutenylcarbazole.

13. The photopolymer type holographic recording medium according to claim 9, wherein, The photosensitizer-initiator combination comprises a photosensitizer and a photoinitiator; the mass ratio of the photosensitizer to the photoinitiator is (0.001-1):(0.1-3).

14. The photopolymer type holographic recording medium according to claim 13, wherein, The photosensitizer is selected from at least one of cyanine dyes, fluorescein dyes, coumarin ketone dyes, nitrogen-containing aromatic heterocyclic compounds, aromatic amine compounds, and benzylidene cycloalkane ketone compounds; The photoinitiator is selected from one or more of benzophenone, alkylbenzophenone, 4,4'-bis(dimethylamino)benzophenone, anthrone and halogenated benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, diacylphosphine oxide, phenyl dihydroxyacetate, camphorquinone, α-aminoalkylphenyl ketone, α,α-dialkoxyacetophenone, α-hydroxyalkylphenyl ketone, tetrabutylammonium triphenylhexylborate, tetrabutylammonium tri-(3-fluorophenyl)hexylborate, tetrabutylammonium tri-(3-chloro-4-methylphenyl)hexylborate, ferrocene compounds, iodonium salts, thiodonium salts, and hexaaryldiimidazole.

15. The photopolymer type holographic recording medium according to claim 9, wherein, The chain transfer agent is a thiol compound; the catalyst is a tertiary amine catalyst or an organometallic catalyst; the additive is selected from one or more of defoamers, leveling agents and plasticizers.

16. The photopolymer-type holographic recording medium as described in claim 15, wherein, The chain transfer agent is selected from one or more of dodecyl mercaptoethanol, hexamethylene mercaptoethanol, phenylethyl mercaptoethanol, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, and 4-methyl-4H-1,2,4-triazole-3-thiol.

17. The photopolymer type holographic recording medium according to claim 15, wherein, The catalyst is selected from at least one of the following: triethylenediamine, bis(dimethylaminoethyl) ether, dimethylethanolamine, 2-(2-dimethylaminoethoxy)ethanol, trimethylhydroxyethylpropanediamine, N,N-bis(dimethylaminopropyl)isopropanolamine, dibutyltin dilaurate, stannous octoate, potassium carboxylate catalysts, and bismuth carboxylate catalysts.

18. The photopolymer type holographic recording medium according to claim 15, wherein, The defoamer is an organosilicon defoamer and / or a polymeric defoamer without organosilicon, and the defoamer accounts for less than or equal to 3 parts by weight of the photopolymeric holographic recording medium. The leveling agent is an organosilicon surface additive, and the leveling agent accounts for less than or equal to 3 parts by weight of the photopolymer holographic recording medium. The plasticizer is selected from at least one of toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, and phthalates, and the plasticizer accounts for less than or equal to 3 parts by weight of the photopolymer holographic recording medium.

19. A holographic optical element, wherein, The raw material of the holographic optical element includes the photopolymer type holographic recording medium as described in any one of claims 8 to 18.

20. An optical device, wherein, Includes the holographic optical element as described in claim 19.

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