4, 4, 4apos; -bis (omega-alkenyl thioether) diphenyl sulfide monomer, photopolymer type holographic recording medium, preparation method of photopolymer type holographic recording medium, grating and optical device

Abstract

The invention discloses a 4, 4 '-bis (omega-alkenyl thioether) diphenyl sulfide monomer and a preparation method, the structural general formula of the 4, 4'-bis (omega-alkenyl thioether) diphenyl sulfide monomer is shown in the specification, n represents the number of methylene and is a positive integer, n = 1-10, the refractive index of a polymer obtained after the monomer and 4 '4-dimercapto diphenyl sulfide are polymerized is larger than 1.65 and smaller than 1.8, diffraction efficiency is remarkably improved, the preparation method is easy to operate, and the preparation method is suitable for industrial production. The invention further provides a photopolymer type holographic recording medium containing the monomer and a preparation method of the photopolymer type holographic recording medium, the sensitivity of the holographic recording medium is larger than 100 cm / mJ, the diffraction efficiency of a recording grating is larger than 95%, the refractive index modulation degree is larger than 0.1, the shrinkage rate is lower than 1%, and the preparation method is simple, controllable and suitable for industrial production. The invention also provides a volume holographic grating containing the holographic recording medium, a holographic optical element and an optical device.

Description

Technical Field

[0001] This application relates to the field of holographic materials technology, and in particular to a 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer, a photopolymer-type holographic recording medium and its preparation method, a grating and an optical device. Background Technology

[0002] Existing photopolymer holographic recording media mostly use acrylate monomers as recording monomers. However, acrylate monomers have a large volume shrinkage rate after polymerization, which leads to grating shift, distortion or blurring of the reproduced image, and decreased diffraction efficiency. Summary of the Invention

[0003] The purpose of this application is to provide a 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer to solve the problem of large volume shrinkage after monomer polymerization.

[0004] In a first aspect, this application provides a 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer, the general structural formula of which is as follows:

[0005] Wherein, n represents the number of methylene groups and is a positive integer, n = 1 to 10, and the refractive index of the 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer is greater than 1.65 and less than 1.8.

[0006] As can be seen from the above technical solutions, the 4,4′-bis(ω-olefin thioether)diphenyl sulfide monomer provided in the first aspect of this application has a refractive index greater than 1.6 and less than 1.7. After polymerization with 4′4-dimercaptodiphenyl sulfide, the refractive index is greater than 1.65 and less than 1.8, which can effectively match common photosensitive resin systems, reduce light scattering loss during holographic recording, and improve diffraction efficiency. At the same time, the higher refractive index helps to enhance the optical anisotropy of the material and optimize the resolution and storage capacity of the hologram.

[0007] Secondly, this application provides a method for preparing the above-mentioned 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer, the preparation method comprising:

[0008] At 0°C, 4′4-dimercaptodiphenyl sulfide was dissolved in a solvent and an alkaline reagent was slowly added, and the mixture was stirred for a first time to form a first solution.

[0009] Compound M1 was added dropwise to the first solution and stirred for a second time. Then, excess solvent was removed, and the 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer was obtained by separation.

[0010] The general structural formula of compound M1 is as follows: n represents the number of methylene groups and is a positive integer, n = 1 to 10.

[0011] As can be seen from the above technical solutions, the preparation method of 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer provided in the second aspect of this application can obtain 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer with high yield through two-step reaction. The synthesis conditions are simple and easy to operate, which is convenient for large-scale production.

[0012] Thirdly, this application provides a photopolymer-type holographic recording medium, including a writing monomer, wherein the writing monomer includes the 4,4′-bis(ω-alkenyl thioether) diphenyl sulfide monomer and 4′4-dimercaptodiphenyl sulfide.

[0013] As can be seen from the above technical solutions, the third aspect of the present invention provides a photopolymer-type holographic recording medium containing the above-mentioned 4,4′-bis(ω-alkenyl thioether) diphenyl sulfide monomer. The 4,4′-bis(ω-alkenyl thioether) diphenyl sulfide monomer and 4′4-dimercaptodiphenyl sulfide form a writing monomer component with a high refractive index and a low shrinkage rate through a thiol-ene click reaction. 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-type holographic recording medium.

[0014] Fourthly, this application provides a method for preparing the aforementioned photopolymer-type holographic recording medium, comprising:

[0015] Weigh the compound having multiple isocyanate reactive functional groups, the polyisocyanate group compound, the writing monomer, the photoinitiator system, the chain transfer agent, the catalyst and the additive into a container, and stir thoroughly until dissolved to form a mixed solution;

[0016] The mixture solution was filtered using a filter membrane to obtain a second solution;

[0017] The second solution is coated onto the substrate and dried to obtain the photopolymer holographic recording medium.

[0018] As can be seen from the above technical solutions, the preparation method of the photopolymer-based holographic recording medium provided in the fourth aspect of the present invention is simple to operate and low in cost. It can ensure uniform dispersion of each component, improve the light transmittance and refractive index modulation of the holographic recording medium, thereby enhancing the resolution and diffraction efficiency of the hologram. In addition, the filtering step can effectively remove impurities, reduce light scattering, and improve the storage stability and imaging quality of the holographic medium.

[0019] Fifthly, this application provides a volume holographic recording grating, wherein the photopolymer holographic recording medium used in the volume holographic recording grating includes the photopolymer holographic recording medium as described above.

[0020] Sixthly, this application provides a holographic optical element, the raw material of which includes the photopolymer type holographic recording medium as described above.

[0021] In a seventh aspect, this application provides an optical device including the holographic optical element as described above.

[0022] As can be seen from the above technical solutions, the volume holographic recording grating, holographic optical element and optical device proposed in this invention have holographic performance with high diffraction efficiency, high sensitivity and high refractive index modulation. The optical device has excellent holographic performance, clear picture and can store a large amount of data. Attached Figure Description

[0023] Figure 1 A schematic flowchart illustrating the steps of a method for preparing a 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer provided in an embodiment of this application;

[0024] Figure 2 This is a schematic flowchart illustrating the steps of a method for preparing a photopolymer-type holographic recording medium according to an embodiment of this application. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some 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.

[0026] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0027] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the application. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0028] It should also be further understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0029] The following detailed description of some embodiments of this application is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0030] It should be understood that photopolymer-based holographic recording media materials used for holographic recording utilize light to polymerize writing monomers, which then form a refractive index-modulated phase-type holographic grating with the film-forming resin to achieve holographic recording. In the coherent bright region, monomer polymerization is consumed, resulting in a decrease in concentration, while in the coherent dark region, monomers hardly react. The difference in monomer concentration between the bright and dark regions causes monomers in the dark region to begin migrating 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 refractive index-modulated phase-type volume holographic grating.

[0031] Existing photopolymer holographic recording media mostly use acrylate monomers as recording monomers. After polymerization, acrylate monomers have a large volume shrinkage rate (usually greater than 8%), which leads to the offset of the recording grating and a large deviation from the theoretical design.

[0032] It should be noted that photopolymer-based holographic recording media with superior performance typically require the film-forming resin to have a lower refractive index and the writing monomer to have a higher refractive index. However, the refractive index of acrylate monomers is usually below 1.60, thus resulting in a small difference in refractive index between the writing monomer and the film-forming resin, typically only 0.1 to 0.2.

[0033] Based on this, this application provides a 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer as a component of a writing monomer, the general structural formula of which is shown in Formula P1: Wherein, n represents the number of methylene groups and is a positive integer, n = 1 to 10, and the refractive index of the 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer is greater than 1.6 and less than 1.7.

[0034] For example, when n=1, the structural formula of P1 is:

[0035]

[0036] In this embodiment, the 4,4′-bis(ω-olefin thioether)diphenyl sulfide monomer has a high refractive index, which is greater than 1.6 and less than 1.7. It can effectively match common photosensitive resin systems, reduce light scattering loss during holographic recording, and improve diffraction efficiency. At the same time, the high refractive index helps to enhance the optical anisotropy of the material and optimize the resolution and storage capacity of the hologram.

[0037] This application also provides a method for preparing the above-mentioned 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer, including:

[0038] Step S101: At 0°C, 4′4-dimercaptodiphenyl sulfide is dissolved in a solvent and an alkaline reagent is slowly added, and the mixture is stirred for a first time to form a first solution.

[0039] Step S102: Compound M1 is added dropwise to the first solution and stirred for a second time. Excess solvent is then removed, and the 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer is obtained.

[0040] The general structural formula of compound M1 is as follows: n represents the number of methylene groups and is a positive integer, n = 1 to 10.

[0041] It is understood that in step S101, the proton on the thiol group in 4′4-dimercaptodiphenyl sulfide can be abstracted by using a base reagent to generate a thiol anion, thereby activating 4′4-dimercaptodiphenyl sulfide. In step S102, compound M1 is added dropwise to the reaction system, meaning that there is an excess of activated 4′4-dimercaptodiphenyl sulfide and a small amount of compound M1 in the reaction system, to ensure that compound M1 is completely reacted. The generated thiol anion further attacks the electrophilic site in compound M1, promoting the substitution reaction between 4′4-dimercaptodiphenyl sulfide and compound M1 to generate 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer, where ω indicates that the double bond is located at the end of the carbon chain, without limiting the number of methylene (CH2) groups.

[0042] In this embodiment, the desired 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer can be synthesized through a two-step reaction, with a monomer yield of over 95%. The synthesis conditions are simple and easy to operate, facilitating large-scale production.

[0043] In some embodiments, the alkaline reagent includes, but is not limited to, sodium hydride, potassium hydride, potassium hydroxide, sodium hydroxide, sodium methoxide, sodium tert-butoxide, potassium tert-butoxide, lithium diisopropylaminophosphate, potassium phosphate, potassium carbonate, and sodium carbonate.

[0044] It is worth noting that when adding the alkaline reagent, it should be added slowly and in multiple batches while stirring to ensure a more complete reaction and full activation of the compound 4′,4-dimercaptodiphenyl sulfide. Since the reaction is exothermic, to avoid overheating that could lead to increased byproducts or decomposition of the target substance, the reaction should be carried out at 0°C. For example, using an ice bath helps control the reaction rate, thereby improving the yield and selectivity of the main reaction, reducing the volatilization of volatile substances and the degradation of unstable substances, and also facilitating subsequent separation and purification of the target product. It is understood that the alkaline reagent can also consume byproducts (such as HBr) generated in the reaction system, thus significantly improving reaction efficiency.

[0045] Furthermore, the solvent used in step S101 may be one or more of petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, toluene, acetonitrile, N,N-dimethylformamide, or dimethyl sulfoxide. It should be noted that the above solvents are merely illustrative, and the solvents that can be used in this application are not limited to these.

[0046] It is understandable that these solvents are well compatible with 4′4-dimercaptodiphenyl sulfide, compound M1, and the hydride, making it easy to control the concentration of the two compounds and make the reaction system more uniform.

[0047] Meanwhile, these solvents have low boiling points or are easily removed through simple post-experimental processing. For example, after the reaction is complete, the solvent can be removed by rotary evaporation using a rotary evaporator, or the reaction system can be separated and extracted before removing the solvent by rotary evaporation, thereby obtaining the desired reactant, such as compound P1, which is convenient for further processing.

[0048] For example, when the reaction solvent is a high-boiling-point solvent, a low-boiling-point solvent with good solubility for the target product (i.e., 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer) is used to extract the mixture after the reaction in step S102. After extraction, the mixture is washed sequentially with saturated NaCl solution, saturated NaHCO3 solution and deionized water. The organic phase is dried with anhydrous sodium sulfate, and excess solvent is removed by rotary evaporation. The 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer of this application is then obtained by column chromatography.

[0049] In some embodiments, the compound 4′4-dimercaptodiphenyl sulfide is stirred and reacted with an alkaline reagent for a first time of 0.5h to 10h, for example, 0.5h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, so that the compound 4′4-dimercaptodiphenyl sulfide reacts fully with the alkaline reagent.

[0050] In some embodiments, controlling the reaction time of compound 4′4-dimercaptodiphenyl sulfide and compound M1, i.e., the second reaction time being 0.5h to 10h, can ensure that the reaction is complete while keeping the overall reaction time within a reasonable range. For example, the reaction time can be 0.5h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, or 10h.

[0051] In some embodiments, the molar ratio of compound 4′4-dimercaptodiphenyl sulfide to compound M1 is 1:(2-4), and the molar ratio of the base reagent to compound M1 is 1:1. Within the above ratio range, the reaction proceeds reasonably, the hydrogen on the thiol group of compound 4′4-dimercaptodiphenyl sulfide can be fully abstracted by the base reagent, and the reaction between compound 4′4-dimercaptodiphenyl sulfide and compound M1 is relatively complete with little residue.

[0052] Typical, but not limiting, molar ratios of compound 4′4-dimercaptodiphenyl sulfide, base reagent, and compound M1 are 1:2:2, 1:2.5:2.5, 1:3:3, 1:3.5:3.5, and 1:4:4.

[0053] This application also provides a photopolymer-type holographic recording medium, including a writing monomer, which includes 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer and 4′4-dimercaptodiphenyl sulfide.

[0054] In this embodiment, 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer and 4′4-dimercaptodiphenyl sulfide undergo an alkene-thiol click reaction, resulting in a shrinkage rate of <1% after polymerization of the writing monomer. Furthermore, the two components work together to form a writing monomer component with a high refractive index, thereby enabling the writing monomer and the film-forming resin to have a greater refractive index difference. This provides the necessary material basis for the formation of a phase-type volume holographic grating with refractive index modulation in a photopolymer holographic recording medium.

[0055] It is understandable that 4,4′-dimercaptodiphenyl sulfide has two thiol groups, which can react with two alkenyl sulfide groups simultaneously to form crosslinking points, thereby achieving intermolecular crosslinking or polymerization, thus transforming linear or branched polymers into highly crosslinked three-dimensional network structures, improving the mechanical strength, thermal stability or solvent resistance of materials.

[0056] In some embodiments, the molar ratio of 4,4′-bis(ω-alkenyl thioether)diphenyl sulfide monomer to 4′4-dimercaptodiphenyl sulfide is 1:1. Optionally, the content of 4,4′-bis(ω-alkenyl thioether)diphenyl sulfide monomer in the entire photopolymer holographic recording medium is 0.1 to 30 wt%.

[0057] Typically, but not limitingly, the content of 4,4′-bis(ω-alkenylthioetheryl)diphenyl sulfide monomer in the entire photopolymer holographic recording medium can be 0.1 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, or any combination of two values.

[0058] In this embodiment, the molar ratio of 4,4′-bis(ω-olefin thioether)diphenyl sulfide monomer to 4′4-dimercaptodiphenyl sulfide is 1:1, which not only ensures complete crosslinking and maximizes crosslinking efficiency, avoiding unreacted groups, but also effectively prevents the resulting polymer from having an excessively low molecular weight. Thus, the resulting writing monomer has a sufficient concentration to achieve the concentration difference between the bright and dark areas after the reaction under light illumination.

[0059] Furthermore, in some embodiments, the photopolymer-type holographic recording medium further includes a film-forming resin, a photoinitiating system, a chain transfer agent, a catalyst, and additives, wherein the film-forming resin is formed from compounds having multiple isocyanate reactive functional groups and polyisocyanate group compounds. When the film-forming resin and the writing monomer are combined, a phase-type volume holographic grating with refractive index modulation and refractive index difference can be formed.

[0060] In some embodiments, the photopolymer holographic recording medium has a photosensitivity greater than 100 cm / mJ, a recording grating diffraction efficiency greater than 95%, a refractive index modulation degree greater than 0.1, and a shrinkage rate less than 1%.

[0061] In some embodiments, the mass ratio of the compound having multiple isocyanate reactive functional groups, the polyisocyanate group compound, the above-mentioned writing monomer, the photoinitiator system, the chain transfer agent, the catalyst and the additive is (30-70):(10-50):(20-60):(0.1-4):(0.1-3):(0.1-3):(0.1-7).

[0062] In this embodiment, by rationally controlling the composition ratio of the photopolymer holographic recording medium, the various components can work together fully, and the holographic performance of the final photopolymer holographic recording medium will not deteriorate due to an excess or deficiency of a certain component, thus ensuring that the overall holographic performance of the final photopolymer holographic recording medium is better.

[0063] In some embodiments, the isocyanate reactive functional group is a hydroxyl group. Compounds having multiple isocyanate reactive functional groups include compounds with a refractive index less than or equal to a first refractive index threshold and having two or more hydroxyl functional groups, wherein the first refractive index threshold is any value between 1.5 and 1.55. Optionally, polyisocyanate-based compounds include compounds with a refractive index less than or equal to a second refractive index threshold and having two or more isocyanate groups, wherein the second refractive index threshold is any value between 1.5 and 1.55.

[0064] Typically, but not restrictively, the first refractive index threshold can be 1.5, 1.51, 1.52, 1.53, 1.54, 1.55, or any value between any two values, and the second refractive index threshold can be 1.5, 1.51, 1.52, 1.53, 1.54, 1.55, or any value between any two values.

[0065] In this embodiment, a compound with multiple isocyanate reactive functional groups having a refractive index less than or equal to 1.5 to 1.55 forms a low-refractive-index film-forming resin with a polyisocyanate group compound having a refractive index less than or equal to 1.5 to 1.55. The low-refractive-index film-forming resin forms a significant refractive index difference (Δn≥0.1) with the high-refractive-index recording monomer (i.e., the refractive index of the above-mentioned 4,4′-bis(ω-alkenyl thioether) diphenyl sulfide monomer is 1.65 to 1.8), which can enhance the diffraction efficiency of the holographic grating and at the same time avoid the increase in background noise caused by the high refractive index of the substrate itself.

[0066] Furthermore, in some examples, the compound having multiple isocyanate reactive functional groups may be one or more of tetraethylene glycol, trimethylolethane, glycerol, triethanolamine, polyester polyols with a molecular weight of 200 to 2000, polycarbonate polyols, and polyether polyols, but is not limited thereto.

[0067] Polyisocyanate compounds include, but are not limited to, 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.

[0068] In some implementations, the photoinitiation system is composed of a photosensitizer and a photoinitiator, which work synergistically to construct a broadband visible light initiation system. The photosensitizer selectively absorbs laser energy at specific wavelengths (e.g., 532 nm or 633 nm) and activates the photoinitiator through an energy transfer mechanism, thereby significantly expanding the system's photosensitive wavelength range. Therefore, different broadband responses can be achieved by controlling the type of photosensitizer. 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. The activated photoinitiator efficiently generates active free radicals, rapidly initiating monomer polymerization reactions, thus enabling the construction of a holographic grating structure. This improves the photosensitivity of the photopolymer-based holographic recording medium and enhances compatibility with lasers of different wavelengths, providing a more flexible light source selection scheme for holographic storage.

[0069] It is understandable that when a photoinitiator with a suitable wavelength is selected in the raw materials of a photopolymer holographic recording medium, a photosensitizer may not be added. For example, when the photoinitiator is diacetic titanium (Irgacure 784), a photosensitizer may not be added. This highly reactive orange solid photoinitiator can initiate the polymerization reaction of unsaturated resins under visible or ultraviolet light.

[0070] In some examples, the mass ratio of photosensitizer to photoinitiator is (0.001 to 1):(0.1 to 3). Typically, but not limitingly, the mass ratio of photosensitizer to photoinitiator can be 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, or 1:3, etc.

[0071] By adjusting the ratio of photosensitizer and photoinitiator within the above range, the energy transfer efficiency of the photosensitizer and the free radical yield of the photoinitiator can be balanced, avoiding energy waste caused by excessive photosensitizer or side reactions caused by excessive initiator. This allows for efficient initiation of the polymerization reaction while controlling the reaction rate within a reasonable range, thus controlling the grating formation speed within a certain range and ensuring the light transmittance of the photopolymer holographic recording medium, thereby achieving excellent diffraction efficiency.

[0072] Among them, photosensitizers are dyes that have high electron transfer efficiency under light irradiation, including but not limited to cyanine dyes, fluorescein dyes, coumarin ketone dyes, nitrogen-containing aromatic heterocyclic compounds, aromatic amine compounds, and benzylidene cycloalkanes ketone compounds.

[0073] For example, the photosensitizer may be one or more of the following: neomethylene blue, thionine, basic yellow, pinacyanin chloride, rhodamine 6G, gallium cyanide, ethyl violet, Victoria blue R, azurite blue, methylene blue, Astrazon Orange G, Darrow red, pyrrole red Y, basic red 29, quinaldinium red, crystal violet, ethyl violet, brilliant green, pyrimethium I, azurite A, crystal violet cyanocyanate, malachite green cyanocyanate, etc.

[0074] Photoinitiators are initiators that can be activated by photochemical radiation and initiate polymerization reactions of corresponding polymerizable groups, including but not limited to aromatic ketones, benzoin and its derivatives, benzoyl ketals, acylphosphine oxides, ammonium arylboronate, chromium salts, aryl diazonium salts, onium salts, and organometallic compounds.

[0075] Specifically, the photoinitiator can be one or more of the following: 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, hexaaryldiimidazole, etc.

[0076] As a chain transfer agent, the chain transfer agent can control the polymer chain length within a certain reasonable range and effectively prevent excessive polymerization, ensuring that the final holographic recording medium has the required optical properties and diffraction efficiency.

[0077] In some embodiments, the chain transfer agent may be a thiol compound, such as one or more of dodecyl mercaptoethanol, mercaptoethanol, hexamethylene mercaptoethanol, phenylethyl mercaptoethanol, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, 4-methyl-4H-1,2,4-triazole-3-thiol, but not limited thereto.

[0078] It is understandable that the molecular weight of the polymerization of 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer and 4′4-dimercaptodiphenyl sulfide can be controlled by the photoinitiator system, the amount of chain transfer agent used, and the reaction conditions. The amount used can be appropriately adjusted according to their types.

[0079] As a catalyst, the catalyst can effectively increase the reaction rate of the relevant components and the consumption rate of the relevant components after exposure, thereby quickly forming the concentration difference of monomers in the bright and dark areas and realizing the phase-type volume holographic grating with refractive index modulation.

[0080] In some embodiments, the catalyst can be a tertiary amine catalyst or an organometallic catalyst, such as 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, but not limited thereto.

[0081] For example, additives can be selected from at least one of defoamers, leveling agents, plasticizers, and dehydrating agents. For instance, as defoamers, defoamers include silicone defoamers and silicone-free polymeric defoamers. Defoamers are mainly used to eliminate or suppress bubbles generated during material preparation and photocuring to ensure high resolution, high diffraction efficiency, and structural uniformity of the hologram.

[0082] Specifically, the defoamer can be selected from 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, DC65 and AFE-7820 manufactured by Dow Corning, or any mixture of these defoamers in any proportion, but is not limited thereto. Among them, the BYK series defoamers have excellent defoaming performance, good compatibility with other components, and good dispersibility. 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. The defoamer content in the photopolymer holographic recording medium is less than or equal to 3 wt%. Typically, but not limitingly, the defoamer content in the photopolymer holographic recording medium can be 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, etc.

[0083] In a specific example, the leveling agent is an organosilicon surface additive, and the leveling agent accounts for less than or equal to 3 wt% of the photopolymer holographic recording medium. Typically, but not limitingly, the defoamer accounts for 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, etc. of the photopolymer holographic recording medium.

[0084] The leveling agent may be selected from BYK series leveling agents with excellent leveling properties manufactured by BYK Corporation, such as BYK-302, BYK-306, BYK-307, BYK-327, BYK-329, BYK-333, BYK-356, BYK-358, BYK-378, BYK-3455, BYK-3566, or any proportion of these surface additives, but is not limited thereto.

[0085] As a plasticizer, the plasticizer increases the plasticity of the polymer by intercalating between polymer molecular chains, weakening intermolecular stress, increasing molecular chain mobility, and reducing crystallinity. In specific examples, the plasticizer may be selected from one or more of toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, and phthalates, but is not limited to these. The plasticizer content in the photopolymer holographic recording medium is less than or equal to 3 wt%. Typically, but not limitingly, the plasticizer content in the photopolymer holographic recording medium may be 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, etc.

[0086] It is understandable that residual moisture in photopolymer-based holographic recording media may cause hydrolysis and failure of the photoinitiator system (such as the photoinitiator), reducing photosensitivity. Simultaneously, moisture can react with isocyanate groups (-NCO) involved in film-forming resin, generating urea bonds and releasing CO2, leading to bubbles or microstructural defects. Therefore, adding a dehydrating agent to maintain system dryness ensures the efficiency of the photopolymerization reaction, thereby improving the uniformity of the holographic grating and the storage life of the medium.

[0087] As dehydrating agents, dehydrating agents include, but are not limited to, p-toluenesulfonyl 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.

[0088] In some embodiments, the content of the dehydrating agent in the photopolymer holographic recording medium is less than or equal to 3 wt%. Typically, but not limitingly, the content of the dehydrating agent in the photopolymer holographic recording medium can be 0.1 wt%, 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, etc.

[0089] This application also provides a method for preparing a photopolymer-based holographic recording medium, the method comprising:

[0090] Step S201: Weigh the compound with multiple isocyanate reactive functional groups, the polyisocyanate group compound, the writing monomer, the photoinitiator system, the chain transfer agent, the catalyst and the additives into a container, and stir thoroughly until dissolved to form a mixed solution.

[0091] Step S202: Filter the mixture solution using a filter membrane to obtain a second solution.

[0092] Step S203: The second solution is coated onto the substrate and dried to obtain the photopolymer holographic recording medium.

[0093] For example, drying is carried out in a dark room with a humidity of 10% to 85% and a temperature of 20°C to 50°C.

[0094] Furthermore, this application provides a volume holographic recording grating, wherein the photopolymer holographic recording medium used in the volume holographic grating includes the photopolymer holographic recording medium described in any of the above embodiments.

[0095] It is understandable that volume holographic recording gratings are fabricated by exposing photopolymer holographic recording media using the principle of light interference. Therefore, the holographic optical properties of the photopolymer holographic recording media determine the quality of the volume holographic recording grating.

[0096] As can be seen from the above, the volume holographic recording grating proposed in this application has high sensitivity, greater than 100 cm / mJ, and the diffraction efficiency of the recording grating is greater than 95%, and the refractive index modulation degree is greater than 0.1.

[0097] This application also provides a holographic optical element, the raw material of which includes the aforementioned photopolymer-type holographic recording medium. This holographic optical element includes, but is not limited to, a volume holographic grating.

[0098] 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 holographic performance with high diffraction efficiency, high sensitivity and high refractive index modulation rate.

[0099] This application also provides an optical device, including the holographic optical element 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 and providing very fast data transfer speeds.

[0100] 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 of this application. The optical device has excellent holographic performance, clear image, and can store a large amount of data.

[0101] The following describes, in conjunction with specific embodiments, the preparation method of the 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer and the photopolymer holographic recording medium containing the 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer of this application.

[0102] Example 1

[0103] In this embodiment, the structural formula of the 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer is P1-1:

[0104]

[0105] The preparation method of 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer with structural formula P1-1 includes the following steps: at 0℃, 4′4-dimercaptodiphenyl sulfide is dissolved in tetrahydrofuran and sodium hydride is slowly added. After stirring for 0.5 h, compound M1-1 is added dropwise and reacted for 1 h. Excess solvent is removed by rotary evaporation, and the target product, namely 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer P1-1, is obtained by column chromatography.

[0106] The characterization data of monomer P1-1 are as follows:

[0107] 1 H NMR (500MHz, CDCl3) δ7.38–7.32(m,2H),7.32–7.26(m,2H),5.98–5.85(m,1H),5.31–5.23(m,1H),5.18–5.11(m,1H),3.45(d,J=6.4Hz,2H).

[0108] 13 C NMR (125MHz, CDCl3) δ135.85,135.84,135.79,135.78,134.41,133.73,133.71,133.69,133.67,129 .11,129.09,128.34,128.31,128.30,128.29,117.49,117.47,117.44,117.42,38.65,38.60,38.56.

[0109] Example 2

[0110] In this embodiment, the structural formula of the 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer is P1-2:

[0111]

[0112] The preparation method of 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer with structural formula P1-2 includes the following steps: at 0℃, 4′4-dimercaptodiphenyl sulfide is dissolved in tetrahydrofuran and potassium tert-butoxide is slowly added. After stirring for 0.5 h, compound M1-2 is added dropwise and reacted for 1 h. Excess solvent is removed by rotary evaporation, and the target product, namely 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer P1-2, is obtained by column chromatography.

[0113] The characterization data of monomer P1-2 are as follows:

[0114] 1H NMR (500MHz, CDCl3) δ7.37–7.31(m,2H),7.31–7.25(m,2H),5.89–5.76(m,1H),5.18–5.11(m,2H),2.89(t,J=8.8Hz,2H),2.32(td,J=8.8,7.2Hz,2H).

[0115] 13 C NMR (125MHz, CDCl3) δ137.59,134.94,134.93,134.88,134.86,134.75,128.78,128.76,128.17,128.14,128.11,128.09, 115.66,115.65,115.64,115.61,115.60,115.59,34.45,34.43,34.40,33.42,33.39,33.37,33.36,33.34,33.32,33.30.

[0116] Example 3

[0117] In this embodiment, the structural formula of the 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer is P1-3:

[0118]

[0119] The preparation method of 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer with structural formula P1-3 includes the following steps: at 0℃, 4′4-dimercaptodiphenyl sulfide is dissolved in ethyl acetate and sodium hydride is slowly added. After stirring for 0.5 h, compound M1-3 is added dropwise and reacted for 1 h. Excess solvent is removed by rotary evaporation, and the target product, namely 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer P1-3, is obtained by column chromatography.

[0120] The characterization data of monomer P1-3 are as follows:

[0121] 1 H NMR(500MHz, CDCl3)δ7.34–7.25(m,4H),5.87–5.73(m,1H),5.17–5.08(m,1H) ,5.02–4.94(m,1H),2.91–2.83(m,2H),2.12–2.04(m,2H),1.58–1.44(m,4H).

[0122] 13C NMR (125MHz, CDCl3) δ138.33,138.29,138.27,138.24,134.58,134.57,134.52,13 4.51,133.89,128.82,128.80,128.52,128.49,128.46,128.44,114.97,114.96,11 4.95, 114.92, 114.91, 114.89, 34.02, 34.00, 33.98, 33.97, 33.48, 33.46, 33.45, 33.43, 33.41, 33.40, 28.66, 28.64, 28.63, 28.61, 28.59, 27.62, 27.60, 27.59, 27.56.

[0123] Example 4

[0124] In this embodiment, the structural formula of the 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer is P1-4:

[0125]

[0126] The preparation method of 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer with structural formula P1-4 includes the following steps: at 0℃, 4′4-dimercaptodiphenyl sulfide is dissolved in tetrahydrofuran and lithium diisopropylamino is slowly added. After stirring for 0.5 h, compound M1-4 is added dropwise and reacted for 1 h. Excess solvent is removed by rotary evaporation, and the target product, namely 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer P1-4, is obtained by column chromatography.

[0127] The characterization data of monomer P1-4 are as follows:

[0128] 1 H NMR (500MHz, CDCl3) δ7.34–7.24(m,4H),5.87–5.73(m,1H),5.09(ddd,J=13.6,3.4,2.2Hz,1H),5.00–4.93(m, 1H), 2.87 (t, J=7.4Hz, 2H), 2.03 (dt, J=7.7, 6.6Hz, 2H), 1.56 (ttd, J=8.2, 7.4, 0.8Hz, 2H), 1.47–1.31 (m, 6H).

[0129] 13C NMR (125MHz, CDCl3) δ139.11,139.08,139.06,139.04,134.76,134.71,134.70, 133.53,128.74,128.72,128.52,128.50,128.47,128.44,114.36,114.34,114.3 1,114.30,114.28,33.79,33.77,33.75,33.73,29.07,29.04,29.02,29.00,28.99,28.97,28.69,28.67,28.65,28.63,28.62,27.97,27.95,27.93,27.91,27.89.

[0130] Example 5

[0131] In this embodiment, the structural formula of the 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer is P1-5:

[0132]

[0133] The preparation method of 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer with structural formula P1-5 includes the following steps: at 0℃, 4′4-dimercaptodiphenyl sulfide is dissolved in acetonitrile and sodium hydride is slowly added. After stirring for 0.5 h, compound M1-5 is added dropwise and reacted for 1 h. Excess solvent is removed by rotary evaporation, and the target product, namely 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer P1-5, is obtained by column chromatography.

[0134] The characterization data of monomer P1-5 are as follows:

[0135] 1 H NMR (500MHz, CDCl3) δ7.31–7.21(m,4H),5.86–5.72(m,1H),5.09(ddd,J=13.7,3.4,2.3Hz,1H),5.00–4.93(m,1H),2.86(t,J=7.3Hz,2H),2 .03(dt,J=7.7,6.6Hz,2H),1.61–1.51(m,2H),1.51–1.42(m,2H),1.42–1.37(m,2H),1.37–1.32(m,2H),1.29(qdt,J=5.1,3.3,1.7Hz,4H).

[0136] 13C NMR (125MHz, CDCl3) δ139.11,139.09,135.04,134.99,134.97,133.82,128.62,128. 60,128.52,128.50,128.47,128.45,114.33,114.31,114.28,114.27,114.26,33.83, 33.81,33.79,33.77,33.75,33.73,29.24,29.22,29.19,29.11,29.10,29.08,29.06,29.04,29.02,29.01,28.99,28.97,28.94,28.91,28.17,28.16,28.14,28.12,28.10.

[0137] Example 6

[0138] In this embodiment, the structural formula of the 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer is P1-6:

[0139]

[0140] The preparation method of 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer with structural formula P1-6 includes the following steps: at 0℃, 4′4-dimercaptodiphenyl sulfide is dissolved in acetonitrile and sodium hydride is slowly added. After stirring for 0.5 h, compound M1-6 is added dropwise and reacted for 1 h. Excess solvent is removed by rotary evaporation, and the target product, namely 4,4′-bis(ω-alkenylthioether)diphenyl sulfide monomer P1-6, is obtained by column chromatography.

[0141] The characterization data of monomer P1-6 are as follows:

[0142] 1 H NMR (500MHz, CDCl3) δ7.31–7.23(m,4H),5.86–5.72(m,1H),5.09(ddd,J=13.6,3.4,2.2Hz,1H),5.00–4.93(m,1H),2.86(t,J=7.3H z,2H),2.03(dt,J=7.7,6.6Hz,2H),1.60–1.50(m,2H),1.50–1.42(m,2H),1.42–1.35(m,3H),1.35–1.26(m,9H),1.26–1.21(m,1H).

[0143] 13C NMR (125MHz, CDCl3) δ139.49,136.68,134.28,127.57,126.79,114.75,34.61,33.82,29.95,29.56,29.48,29.47,29.34,29.29,28.94,28.34.

[0144] Table 1 shows the performance parameters of different 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomers in Examples 1-6.

[0145]

[0146] Table 1

[0147] Example 7

[0148] Photopolymer-type holographic recording media 7-1 to 7-6 were prepared using the 4,4′-bis(ω-olefin thioether)diphenyl sulfide monomer from Examples 1-6. The preparation method involved mixing all components thoroughly, filtering the mixture using a filter membrane, coating the resulting filtrate onto a substrate, and drying it in a darkroom at a humidity of 10%–85% and a temperature of 20°C–50°C to obtain the photopolymer-type holographic recording media. The specific components of the photopolymer-type holographic recording media 7-1 to 7-6 are shown in Tables 2 to 7.

[0149]

[0150] Table 2

[0151]

[0152] Table 3

[0153]

[0154] Table 4

[0155]

[0156] Table 5

[0157]

[0158] Table 6

[0159]

[0160] Table 7

[0161] Comparative Example

[0162] The composition is roughly the same as that of the photopolymer holographic recording medium 7-1 in Example 7. The difference is that the 4,4′-bis(ω-alkenyl thioether) diphenyl sulfide monomer, i.e. P1-1, is not added in the comparative example, but the pentabromophenyl acrylate is increased to 27 wt% to obtain a common photopolymer holographic recording medium.

[0163] Test case

[0164] The performance of the photopolymer holographic recording media 7-1 to 7-6 containing 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer in Examples 7 and the conventional photopolymer holographic recording media of the comparative examples were tested, and the results are shown in Table 8. During the tests, different wavelengths of laser light were selected for exposure of each holographic recording medium in Example 7, depending on the photosensitive system, with an exposure intensity of 3 mW / cm². 2 .

[0165] 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 the photosensitivity (S) of the photopolymer holographic recording medium are calculated by formulas (1) to (3).

[0166]

[0167] 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.

[0168] The thickness changes of the photopolymer holographic recording media 7-1 to 7-6 containing 4,4′-bis(ω-olefin thioether) diphenyl sulfide monomer in Example 7 and the ordinary photopolymer holographic recording media of the comparative example before and after exposure were tested using a step meter, and the shrinkage rate β of the photopolymer holographic recording media was calculated by formula (4).

[0169]

[0170] In the formula, d0 is the initial thickness of the sample before exposure, and d p This represents the post-polymerization thickness of the sample after exposure.

[0171]

[0172] Table 8

[0173] In summary, referring to Table 8, the diffraction efficiency and sensitivity of the photopolymer holographic recording medium in this application are significantly higher than those of the comparative example, and the shrinkage rate is smaller. Furthermore, after polymerization of the 4,4′-bis(ω-alkenyl thioether) diphenyl sulfide monomer and 4′4-dimercaptodiphenyl sulfide in Examples 1-6 of this application, the polymer's refractive index is between 1.65 and 1.8, which is high. This effectively increases the refractive index of the writing monomer and further enhances the refractive index difference between the writing monomer and the film-forming resin, thus significantly improving the holographic performance of the photopolymer holographic recording medium containing the 4,4′-bis(ω-alkenyl thioether) diphenyl sulfide monomer of this application.

[0174] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention 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 the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A 4,4'-bis(ω-alkenylthioether)diphenyl sulfide monomer, characterized in that, Its general structural formula is as follows: Wherein, n represents the number of methylene groups and is a positive integer, n = 1 to 10, and the refractive index of the 4,4'-bis((ω-alkenylthioether)diphenyl sulfide monomer is greater than 1.6 and less than 1.

7.

2. A method for preparing the monomer as described in claim 1, characterized in that, The preparation method includes: At 0°C, 4',4-dimercaptodiphenyl sulfide is dissolved in a solvent and an alkaline reagent is slowly added while stirring for a first time to form a first solution; Compound M1 was added dropwise to the first solution and stirred for a second time. Then, excess solvent was removed, and the 4,4'-bis(ω-olefin thioether) diphenyl sulfide monomer was obtained by separation. The general structural formula of compound M1 is as follows: n represents the number of methylene groups and is a positive integer, n = 1 to 10.

3. The preparation method according to claim 2, characterized in that, The solvent is one or more of petroleum ether, dichloromethane, trichloromethane, ethyl acetate, tetrahydrofuran, toluene, acetonitrile, N,N-dimethylformamide, or dimethyl sulfoxide.

4. The preparation method according to claim 2, characterized in that, The alkaline reagent is any one of sodium hydride, potassium hydride, potassium hydroxide, sodium hydroxide, sodium methoxide, sodium hydride, sodium tert-butoxide, potassium tert-butoxide, lithium diisopropylaminophosphate, potassium phosphate, potassium carbonate, and sodium carbonate.

5. A photopolymer-based holographic recording medium, characterized in that, The writing monomer includes the 4,4'-bis(ω-alkenylthioether)diphenyl sulfide monomer and 4'4-dimercaptodiphenyl sulfide.

6. The photopolymer-type holographic recording medium according to claim 5, characterized in that, The molar ratio of the 4,4'-bis(ω-olefin thioether) diphenyl sulfide monomer to the 4',4-dimercaptodiphenyl sulfide is 1:1; And / or, the 4,4'-bis(ω-olefin thioether) diphenyl sulfide monomer accounts for 0.1 to 30 wt% of the total content of the photopolymer holographic recording medium.

7. The photopolymer-type holographic recording medium according to claim 5, characterized in that, The photopolymer-type holographic recording medium further includes a film-forming resin, a photosensitive initiation system, a chain transfer agent, a catalyst, and additives. The film-forming resin includes compounds with multiple isocyanate reactive functional groups and polyisocyanate-based compounds.

8. The photopolymer-type holographic recording medium according to claim 7, characterized in that, The photosensitive polymer holographic recording medium has a photosensitivity greater than 100 cm / mJ, a recording grating diffraction efficiency greater than 95%, a refractive index modulation degree greater than 0.1, and a shrinkage rate less than 1%.

9. The photopolymer-type holographic recording medium according to claim 7, characterized in that, The mass ratio of the compound having multiple isocyanate reactive functional groups, the polyisocyanate group compound, the writing monomer, the photoinitiating system, the chain transfer agent, the catalyst, and the additive is (30-70):(10-50):(20-60):(0.1-4):(0.1-3):(0.1-3):(0.1-7).

10. The photopolymer-type holographic recording medium according to claim 7, characterized in that, The isocyanate reactive functional group is a hydroxyl group; the compound having multiple isocyanate reactive functional groups includes compounds with a refractive index less than or equal to a first refractive index threshold and having two or more hydroxyl functional groups, wherein the first refractive index threshold is any value between 1.5 and 1.

55. And / or, the polyisocyanate-based compound includes compounds with a refractive index less than or equal to a second refractive index threshold and having two or more isocyanate groups; the second refractive index threshold is any value between 1.5 and 1.55; And / or, the photoinitiating system includes a photosensitizer and a photoinitiator; And / or, the chain transfer agent is a thiol compound; And / or, the catalyst is a tertiary amine catalyst and an organometallic catalyst; And / or, the additives include at least one of defoamers, leveling agents, plasticizers, and dehydrating agents.

11. The photopolymer-type holographic recording medium according to claim 10, characterized in that, The compound having multiple isocyanate reactive functional groups includes at least one of tetraethylene glycol, trimethylolethane, glycerol, triethanolamine, polyester polyol with a molecular weight of 200 to 2000, polycarbonate polyol, and polyether polyol. And / or, the polyisocyanate group compound includes 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; And / or, the chain transfer agent comprises at least one of dodecyl mercaptan, mercaptoethanol, hexamethylene mercaptan, phenylethyl mercaptan, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, and 4-methyl-4H-1,2,4-triazole-3-thiol; And / or, the catalyst comprises 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.

12. The photopolymer-type holographic recording medium according to claim 7, characterized in that, The photosensitizer includes 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 includes aromatic ketone compounds, benzoin and its derivatives, benzoyl ketal, acylphosphine oxide, ammonium arylboronate, chromium salt, aryl diazonium salt, onium salt, organometallic compound, or at least one of these compounds; The mass ratio of the photosensitizer to the photoinitiator is (0.001-1):(0.1-3).

13. The photopolymer-type holographic recording medium according to claim 10, characterized in that, The defoamer is an organosilicon defoamer and / or a polymeric defoamer without organosilicon, and the content of the defoamer in the photopolymeric holographic recording medium is less than or equal to 3 wt%. And / or, the leveling agent is an organosilicon surface additive, and the leveling agent accounts for less than or equal to 3 wt% of the photopolymer holographic recording medium; And / or, 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 wt% of the photopolymer holographic recording medium; And / or, the dehydrating agent includes at least one of p-toluenesulfonyl isocyanate and triethyl orthoformate, and the dehydrating agent accounts for less than or equal to 3 wt% of the photopolymer holographic recording medium.

14. The method for preparing the photopolymer-type holographic recording medium according to any one of claims 5-13, characterized in that, Weigh the compound having multiple isocyanate reactive functional groups, the polyisocyanate group compound, the writing monomer, the photoinitiator system, the chain transfer agent, the catalyst and the additive into a container, and stir thoroughly until dissolved to form a mixed solution; The mixture solution was filtered using a filter membrane to obtain a second solution; The second solution is coated onto the substrate and dried to obtain the photopolymer holographic recording medium.

15. The preparation method according to claim 14, characterized in that, The drying process is carried out in a dark room with a humidity of 10% to 85% and a temperature of 20°C to 50°C.

16. A volume holographic recording grating, characterized in that, The photopolymer holographic recording medium used in the volume holographic recording grating includes the photopolymer holographic recording medium as described in any one of claims 5-13.

17. A holographic optical element, characterized in that, The raw material of the holographic optical element includes the photopolymer holographic recording medium as described in any one of claims 5-13.

18. An optical device, characterized in that, Includes the holographic optical element as described in claim 17.

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