Optical monomer as well as preparation method and application thereof

Abstract

The invention provides an optical monomer as well as a preparation method and application thereof, the structural general formula of the optical monomer is shown in the specification, in the formula, R1 and R2 are groups with the structural formula shown in the specification; or, one of R1 and R2 is hydrogen, and the other one of R1 and R2 is a group shown in the structural formula; r0 in the group represents hydrogen or methyl. The optical monomer provided by the invention has a (methyl) acrylate group and has the properties of high refractive index and low volume shrinkage; the monomer contains a plurality of aromatic rings with high molar refractive index and low molar volume, sulfur atoms with higher molar refractive index and dibenzothiophene groups with both aromatic rings and sulfur, so that the whole molecule of the monomer has extremely high refractive index, and the whole optical monomer is small in molecular weight and convenient to migrate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of holographic material, in particular to an optical monomer and a preparation method and application thereof. BACKGROUND

[0002] The components for making holographic recording medium, such as photosensitive dye, initiator, chain transfer agent, writing monomer, film-forming resin, additive, etc., jointly determine whether the holographic recording medium is excellent in performance.

[0003] The migration rate and the polymerization rate of the writing monomer jointly determine the speed of grating formation, and the migration rate of the writing monomer is faster than the polymerization rate to obtain a grating with stable refractive index modulation. After the writing monomer located in the coherent bright area is polymerized, the unreacted writing monomer located in the coherent dark area quickly migrates to the coherent bright area and extrudes the film-forming resin in the bright area to the coherent dark area, so that the refractive index of the bright area approaches the refractive index of the writing monomer, and the refractive index of the dark area approaches the refractive index of the film-forming resin. At the same time, the writing monomer and the film-forming resin have a refractive index difference to form a refractive index modulated volume holographic grating, and the greater the refractive index difference between the writing monomer and the film-forming resin, the faster the holographic recording medium forms a refractive index modulated volume holographic grating.

[0004] In the refractive index modulated phase volume holographic grating prepared by the photopolymer, the refractive index n of the writing monomer needs to be greater than 1.6. In the related art, the refractive index of the writing monomer that can be used for the photopolymer is usually less than 1.6. The low refractive index is not conducive to recording a holographic grating with high diffraction efficiency. The refractive index difference between the low-refractive-index writing monomer and the film-forming resin is only 0.1-0.2, and the refractive index difference between the writing monomer and the film-forming resin is not significant enough to further improve the holographic performance of the holographic recording medium. SUMMARY

[0005] In view of this, the present application provides an optical monomer and a preparation method and application thereof, aiming to solve at least one of the foregoing technical problems and at least achieve that the optical monomer has a high refractive index to improve the holographic optical performance of the photopolymer type holographic recording medium containing the optical monomer.

[0006] The present application provides an optical monomer, and a preparation method and application thereof. In the formula, R1 and R2 are groups with the structural formula or one of R1 and R2 is hydrogen, and the other of R1 and R2 is a group with the structural formula In the group, R0 represents hydrogen or methyl.

[0007] From the above technical solutions, the optical monomer provided in the first aspect of the present application has a (meth) acrylate group, high refractive index and low volume shrinkage properties; the monomer contains multiple aromatic rings with high molar refractive index and low molar volume, also has a sulfur atom with a relatively high molar refractive index, and a dibenzothiophene group with both aromatic ring and sulfur, so that the entire monomer molecule presents a very high refractive index, and the molecular weight of the entire optical monomer is small, facilitating migration.

[0008] The preparation method of the optical monomer provided in the second aspect of the present application comprises the following steps: dissolving a compound P1, a coupling catalyst, a ligand, a base and a compound P2 in a first solvent, heating and stirring to react, performing post-treatment and separating to obtain a compound P3; the equivalent ratio of the compound P1 to the compound P2 is 1:(1-2).

[0009] The compound P1 has the following structural formula wherein R3 and R4 are both Br, or one of R3 and R4 is H and the other is Br.

[0010] The compound P2 has the following structural formula The compound P3 has the following structural formula wherein R5 and R6 are both groups with the following structural formula or one of R5 and R6 is H and the other is a group with the following structural formula .

[0011] The preparation method of the optical monomer provided in the second aspect of the present application, through the coupling reaction of the compound P1 with the benzothiophene skeleton and halogen bromine and the compound P2 with the phenylboronic acid group and alcohol hydroxyl under the action of the coupling catalyst, the ligand and the base, and the generation of the compound P3 with the benzothiophene skeleton and the phenylthioethanol group, can provide the required structural basis for subsequent further reaction, and provide the benzothiophene group, the aromatic ring and the sulfur atom with a large refractive index contribution for subsequent generation of the final optical monomer.

[0012] The photopolymer type holographic recording medium provided in the third aspect of the present application comprises a writing monomer, the writing monomer comprises the optical monomer and a polymerizable monomer, the optical monomer is the optical monomer of the foregoing embodiments; and / or the optical monomer is the optical monomer prepared by the preparation method of the foregoing optical monomer.

[0013] The photopolymer type holographic recording medium provided by the third aspect of the present application can form a high refractive index writing monomer component through the addition of optical monomers and polymerizable monomers, so that the writing monomer and the film-forming resin can have a greater refractive index difference, thereby providing the required material basis for the photopolymer type holographic recording medium to form a phase type volume holographic grating with refractive index modulation.

[0014] The holographic optical element provided by the fourth aspect of the present application has a raw material comprising the photopolymer type holographic recording medium in any of the foregoing embodiments.

[0015] The holographic optical element provided by the fourth aspect of the present application has excellent holographic performance, high diffraction efficiency, high sensitivity, and small required exposure amount.

[0016] The optical device provided by the fifth aspect of the present application comprises the holographic optical element as described above.

[0017] The optical device provided by the fifth aspect of the present application, such as a head-up display device, an augmented reality device, a virtual reality device, and a photopolymer type holographic storage optical disc, has excellent holographic performance.

[0018] It should be understood that the foregoing general description and the following detailed description are only exemplary and explanatory, and cannot limit the disclosure of the embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can obtain other drawings without creative labor on the basis of these drawings.

[0020] Figure 1 is a holographic exposure characteristic curve diagram of the photopolymer type holographic recording media 8-1, 8-2, 8-3 and 8-4 in Example 8;

[0021] Figure 2 is a holographic exposure characteristic curve diagram of the photopolymer type holographic recording media 8-5, 8-6 and 8-7 in Example 8;

[0022] Figure 3 is a holographic exposure characteristic curve diagram of the comparative example. DETAILED DESCRIPTION

[0023] With reference to the accompanying drawings, the technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0024] The photopolymer material for holographic recording is used to form a refractive index modulated phase type holographic grating by polymerizing the writing monomer under light and forming a refractive index modulated phase type holographic grating with a film-forming resin, and then realizing holographic recording. The writing monomer in the coherent bright area is consumed and the concentration is reduced, while the writing monomer in the coherent dark area hardly reacts. The difference in the concentration of the writing monomer in the bright and dark areas promotes the writing monomer in the dark area to migrate to the bright area, and the film-forming resin in the bright area is squeezed to the dark area. Finally, the refractive index of the bright area approaches the refractive index of the polymer, and the refractive index of the dark area approaches the refractive index of the film-forming resin, thereby forming a refractive index modulated phase type bulk holographic grating.

[0025] Therefore, to improve the performance of the photopolymer, the film-forming resin generally needs to have a lower refractive index, and the writing monomer needs to have a higher refractive index. In the related art, the refractive index of the polymerized low-viscosity monomer that can be used in the photopolymer is generally lower than 1.60, and especially when a multifunctional monomer is used, the refractive index is only about 1.55, so that the refractive index difference between the writing monomer and the film-forming resin is small, and the refractive index difference between the writing monomer and the film-forming resin is not significant, usually only 0.1-0.2.

[0026] In the present application, an optical monomer is provided as a component of the writing monomer, and the refractive index of the optical monomer of the present application is higher than 1.7. The optical monomer with a high refractive index and at least one functionality is combined with an isocyanate-alcohol with a lower refractive index as a film-forming resin to form a refractive index modulated bulk holographic grating with a larger refractive index difference, thereby improving the holographic performance of the photopolymer type holographic recording medium, and making the photopolymer type holographic recording medium have high sensitivity and high recording grating diffraction efficiency.

[0027] In the case of no conflict, the embodiments and features in the embodiments can be combined with each other.

[0028] The optical monomer of the present application will be described below.

[0029] According to the optical monomer provided in the present application, the general structure formula is as follows:

[0030] wherein R1 and R2 are both groups with the structural formula or one of R1 and R2 is hydrogen, and the other of R1 and R2 is a group with the structural formula R0 represents hydrogen or methyl.

[0031] As can be seen from the above, the optical monomer provided by the present application has a (meth)acrylate group, high refractive index and low volume shrinkage property. The monomer contains multiple aromatic rings with high molar refractive index and low molar volume, also has a sulfur atom with a relatively high molar refractive index, and also has a dibenzothiophene group with both aromatic ring and sulfur, so that the entire monomer molecule presents a very high refractive index.

[0032] The entire monomer structure in the present application has at least one functionality, and some monomer structures have at least two functionalities, which can react quickly with the surrounding components during polymerization. For the optical monomer with at least two functionalities, one equivalent of the optical monomer can react with at least two equivalent of other substances during polymerization, so that the reaction rate of the optical monomer in the bright area is faster, thereby causing a concentration difference between the optical monomer in the dark area and the optical monomer in the bright area, effectively promoting the optical monomer in the dark area to move to the bright area.

[0033] The optical monomer of the present application has a small overall molecular weight, and the molecule itself is not easy to agglomerate and has a certain migration rate.

[0034] In some embodiments, the optical monomer is selected from monomers having the following structural formula:

[0035]

[0036] Therefore, the optical monomers of each structure in the above examples all have a high refractive index, and the refractive index is higher than 1.7; the molecule has at least one functionality and has a certain migration rate.

[0037] In some examples, the refractive index of the optical monomer is 1.71-1.73.

[0038] It can be understood that, compared with the monomer in the related art, the refractive index of the monomer is less than 1.6, the refractive index difference between the writing monomer and the film-forming resin is small, and the refractive index difference between the writing monomer and the film-forming resin is not significant enough to make the holographic performance of the optical device prepared poor, the refractive index of the optical monomer of the present application is higher than 1.7, which can effectively improve the exposure sensitivity and diffraction efficiency of the holographic recording in the exposure process after being added to the photopolymer type holographic recording medium.

[0039] The preparation method of the optical monomer of the present application is described below.

[0040] The preparation method of the optical monomer in each of the above examples provided by the present application includes the following steps:

[0041] Step S1, compound P1, coupling catalyst, ligand, base, compound P2 are dissolved in a first solvent, heated and stirred to react, post-treatment and separation to obtain compound P3; the equivalent ratio of compound P1 and compound P2 is 1:(1-2), for example, it can be 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.5, 1:1.7 and 1:2, etc.

[0042] The structural formula of compound P1 is Wherein, R3, R4 are both Br, or one of R3, R4 is H and the other is Br;

[0043] The structural formula of compound P2 is The structural formula of compound P3 is Wherein, R5, R6 are both groups with the structural formula Or one of R5, R6 is H and the other is a group with the structural formula .

[0044] As can be seen from the above, the preparation method of the optical monomer, in step S1, compound P1 with benzothiophene skeleton and functional group halogen bromine and compound P2 with phenylboronic acid group and alcohol hydroxyl are coupled under the action of coupling catalyst, ligand and base, and compound P3 with benzothiophene skeleton and phenylthioethanol group is generated, the activity of the hydroxyl group in compound P3 is high, which can continue to participate in subsequent reactions, and can provide the required structural basis for subsequent further reactions (such as step S2 described below), and provides the benzothiophene group, aromatic ring and sulfur atom with large refractive index contribution for subsequent generation of the final optical monomer.

[0045] The specific reaction mechanism is that the coupling catalyst and the ligand jointly catalyze the step to enable compound P1 and compound P2 to undergo oxidative addition, transmetalation and reductive elimination to generate compound P3, the base reacts with the phenylboronic acid group in compound P2 to generate highly active phenylboronic acid, which promotes the transmetalation step, and finally the halogen bromine and the boronic acid group are eliminated from compound P3, while the benzothiophene skeleton in compound P1 and the phenylthioethanol group in compound P2 are coupled.

[0046] In some embodiments, the molar ratio of the coupling catalyst, the ligand, the base, and the compound P1 is (0.005-0.05):(0.01-0.1):(1-3):1, for example, it can be 0.005:0.01:1:1, 0.05:0.1:3:1, 0.01:0.05:2:1, 0.03:0.07:2.6:1, etc. The required amount of each substance can be adjusted within the above range according to the required reaction rate, reaction time, and reaction degree, so that the progress of the coupling reaction of the compound P1 and the compound P2 in step S1 is controlled within a reasonable range, the hydrolysis of the substrate during the reaction is reduced, the side reaction is reduced, and the compound P3 is efficiently generated, which is beneficial to improve the purity and yield of the compound P3.

[0047] In some embodiments, the coupling catalyst is at least one selected from tetrakis(triphenylphosphine)palladium (also referred to as Pd(PPh3)4), bis(diphenylphosphinoferrocene)palladium dichloride (also referred to as PdCl2(dppf)), palladium acetate (also referred to as Pd(OAc)2), tris(dibenzylideneacetone)dipalladium (also referred to as Pd2(dba)3), bis(triphenylphosphine)palladium dichloride (also referred to as PdCl2(PPh3)2), palladium chloride containing ditertiary butyl phosphine ferrocene ligand (also referred to as Pd(dtbpf)Cl2), bis(triphenylphosphine)palladium dichloride (also referred to as Pd(PPh3)2Cl2), bis(diphenylphosphinoferrocene)nickel chloride (also referred to as NiCl2(dppf)), palladium on carbon (also referred to as Pd / C), Bedford palladium catalyst (also referred to as 2-[bis(2,4-di-tert-butyl-phenoxy)phosphine oxide]-3,5-di(tert-butyl)phenyl-palladium(II) chloride dimer), monodentate phosphine ligand catalyst, palladium catalyst containing tertiary butyl ligand (which can be denoted as Pd(tBu)3-G4), and Buchwald pre-catalyst. Most of the coupling catalysts in these embodiments contain palladium, and some have nickel, which can all enable the coupling reaction to proceed efficiently. In specific embodiments, the monodentate phosphine ligand catalyst can be selected from BI-DIME / AntPhos, etc. DHBOP monodentate phosphine ligand catalyst.

[0048] For example, some coupling catalysts can enable the reaction to proceed at a high speed with the addition of a small amount; some coupling catalysts are easy to handle and have low air sensitivity; some coupling catalysts have strong electronegativity, which is beneficial to oxidative addition reaction; some coupling catalysts have large steric hindrance, which is beneficial to reductive elimination reaction. For example, some coupling catalysts have a wide source and low cost.

[0049] In some embodiments, the ligand is selected from at least one of triphenylphosphine, 2,2'-bis(diphenylphosphino)-l,l'-binaphthyl, 2-dicyclohexylphosphino-2',4',6'- triisopropylbiphenyl, 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl, 1,3- bis(2,4,6-trimethylphenyl)imidazol-2-ylidene, tricyclohexylphosphine, 1,1'- bis(diphenylphosphino)ferrocene. These ligands can work together with the coupling catalyst to enhance the catalytic activity and selectivity of the coupling catalyst, thus making the coupling reaction easier to proceed. For example, in some specific embodiments, the ligand can stabilize Pd(0) and promote the formation of carbon-carbon bonds.

[0050] In some embodiments, the base is selected from at least one of potassium carbonate, sodium carbonate, cesium carbonate, potassium phosphate, potassium fluoride, cesium fluoride, tetrabutylammonium fluoride, barium hydroxide, sodium hydroxide, and potassium trimethylsilanolate. These bases differ in strength and can be selected according to the coupling catalyst selected, as well as the ease of reaction of the reactants and the desired control of reaction time. Strong bases can increase the speed and yield of the reaction. The base is mainly to convert compound P2 into a negatively charged activated body, and then proceed to the transmetalation process. For example, in some specific embodiments, the base can provide a Lewis base environment to activate Pd(0) and promote the formation of intermediates.

[0051] In some embodiments, the first solvent is selected from one or more of organic solvents, or the first solvent is selected from a mixed solution of at least one organic solvent and water, wherein the organic solvent in the first solvent includes toluene, dimethoxyethane, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, dioxane. That is, only organic solvents can be used in this application as the solvents for the dissolution of each of the reactants, coupling catalyst, ligand, and base; or a complex liquid of organic solvents and water can be used to provide the reaction system. The use of the first solvent can make each component involved in the reaction homogeneous, and also serve as a carrier for adjusting the reaction temperature.

[0052] In some embodiments, the reaction is carried out by heating and stirring, and the temperature after heating is 60°C to 120°C, for example, it can be 60°C, 70°C, 80°C, 90°C, 100°C, 110°C, and 120°C, etc. The stirring reaction time is 2h to 24h, for example, it can be 2h, 3h, 5h, 10h, 12h, 13h, 14h, 15h, 17h, 19h, 20h, 22h, and 24h, etc. By reasonably controlling the reaction temperature and reaction time, the reaction process of the entire reaction system can be more reasonably controlled, and the solubility of part of the reactants can be controlled within a certain range, thereby shortening the experimental process.

[0053] In some embodiments, the post-treatment in step S1 further comprises rotary evaporation to remove the excess first solvent, which is particularly suitable for the organic portion in the first solvent. In some embodiments, the separation of compound P3 in step S1 employs column chromatography separation, so that the purity of compound P3 is higher.

[0054] In some embodiments of the present application, the method for preparing the optical monomer of the foregoing embodiments further comprises the following steps:

[0055] Step S2, dissolving compound P3 and an acid-binding agent in a second solvent at a second temperature, stirring and adding compound M2 until the reaction is complete, removing excess reactants, post-treatment and separation to obtain an optical monomer having a general structure of , wherein compound M2 is acryloyl chloride or methacryloyl chloride, and the equivalent ratio of compound P3 to compound M2 is 1:(1-3), for example, the equivalent ratio can be 1:1, 1:1.2, 1:1.3, 1:2 and 1:3, etc. In step S2 of the present application, the hydroxyl group on compound P3 undergoes nucleophilic substitution with the chlorine in compound M2 to generate an optical monomer having a general structure of , which contains an acrylate group (wherein R0 on R1 and R2 represents hydrogen) or a methacrylate group (wherein R0 on R1 and R2 represents methyl), and the (meth)acrylate group has high refractive index and low volume shrinkage properties.

[0056] In some embodiments of the present application, the second temperature is the temperature of an ice bath, which can control the temperature of the reaction to be relatively constant, and can keep the reaction rate within a certain degree, reduce the generation of by-products, help to improve the yield and selectivity of the main reaction, reduce the volatilization of volatile substances and the degradation of unstable substances, and facilitate the subsequent separation and purification of the target product.

[0057] In some embodiments of the present application, the equivalent ratio of compound P3 to the acid-binding agent is 1:(1-4); for example, the equivalent ratio of compound P3 to the acid-binding agent is 1:1, 1:2, 1:3 or 1:4, etc., which is not limited here. The presence of the acid-binding agent can capture the acid generated during the reaction of compound P3 and compound M2, effectively neutralize the protons in the reaction system, reduce the influence of the acid on the reaction, and fix the hydrogen ions in the solution to protect other substances from the acidic environment, thereby facilitating the further reaction of compound P3 and compound M2, so that the reaction can be carried out efficiently. In some embodiments, the acid-binding agent is selected from at least one of triethylamine, pyridine, N,N-diisopropylethylamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, potassium carbonate, ammonium carbonate and sodium carbonate. The raw materials are easy to obtain, and also facilitate the separation of the finally prepared optical monomer.

[0058] In some embodiments of the present application, the second solvent is selected from at least one of ethanol, petroleum ether, dichloromethane, trichloromethane, ethyl acetate, tetrahydrofuran, acetonitrile, N, N-dimethylformamide and dimethyl sulfoxide. The second solvent herein needs to be able to facilitate the reaction of compound P3, compound M2, and to have good compatibility with compound P3, the deacidifying agent and compound M2. For example, in step S2, more specifically, the following solvents can be selected: dichloromethane, trichloromethane, ethyl acetate.

[0059] In some embodiments of the present application, removing the excess reactants includes removing the excess compound M2 by adding dilute hydrochloric acid dropwise. The dilute hydrochloric acid can provide water and hydrogen ions, which can cause the nucleophilic substitution reaction of the acyl chloride group in compound M2 with water to generate hydrogen chloride and (meth)acrylic acid, so that the excess M2 is removed to form water-soluble substances, which are easy to remove.

[0060] In some embodiments of the present application, the optical monomer of the foregoing embodiments is obtained by post-treatment and separation in step S2. The post-treatment and separation include: sequentially washing with saturated NaCl solution, saturated NaHCO3 solution and deionized water, drying the organic phase with anhydrous sodium sulfate, and then removing the excess solvent by rotary evaporation, and then separating the optical monomer by column chromatography.

[0061] Therefore, it can be known that the optical monomer with the structural general formula in the present application is prepared by two-step reactions, i.e., the reaction in step S1 and the reaction in step S2, which can be specifically represented as:

[0062] Step S1,

[0063] Step S2,

[0064] The photopolymer type holographic recording medium containing the optical monomer of the foregoing embodiments or the optical monomer prepared by the foregoing preparation method is described below.

[0065] The photopolymer type holographic recording medium according to the present application comprises a writing monomer, and the writing monomer comprises an optical monomer and a polymerizable monomer, the optical monomer is the optical monomer described above; and / or, the optical monomer is the optical monomer prepared by the preparation method of the optical monomer described above.

[0066] The photopolymer type holographic recording medium according to the present application can form a writing monomer component with a relatively high refractive index by adding the optical monomer and the polymerizable monomer, so that the writing monomer and the film-forming resin can have a larger refractive index difference, thereby providing the required material basis for the photopolymer type holographic recording medium to form a phase type volume holographic grating with refractive index modulation.

[0067] In some examples of the present application, the weight percentage of the writing monomer in the entire photopolymer type holographic recording medium is 11% to 70%. Thus, the writing monomer can have a sufficient concentration to achieve the concentration difference between the bright and dark regions after the reaction under light.

[0068] In some embodiments of the present application, the photopolymer type holographic recording medium further includes a film forming resin, a photosensitive initiation combination agent, a chain transfer agent, a catalyst, and an additive. The film forming resin includes a compound having a plurality of isocyanate reactive functional groups and a polyisocyanate-based compound. When the film forming resin and the writing monomer are combined, a refractive index modulated phase type volume holographic grating having a refractive index difference can be formed.

[0069] In some embodiments of the present application, the photopolymer type holographic recording medium containing the optical monomer includes the following weight fractions of each component:

[0070] The first component: a compound having a plurality of isocyanate reactive functional groups is 15 to 40 parts. For example, it can be 15 parts, 20 parts, 30 parts, 35 parts, 40 parts, etc.

[0071] The second component: a polyisocyanate-based compound is 15 to 40 parts. For example, it can be 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc.

[0072] The third component: an optical monomer is 1 to 30 parts. For example, it can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, etc.

[0073] The fourth component: a polymerizable monomer is 10 to 40 parts. For example, it can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc.

[0074] The fifth component: a photosensitive initiation combination agent is 0.1 to 3 parts. For example, it can be 0.1 parts, 0.2 parts, 0.3 parts, 0.5 parts, 1 parts, 1.5 parts, 2.0 parts, 2.5 parts, 3 parts, etc.

[0075] The sixth component: a chain transfer agent is 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.

[0076] The seventh component: a catalyst is 0.1 to 5 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, 3.5 parts, 4 parts, 4.2 parts, 4.6 parts, 5 parts, etc.

[0077] The eighth component: additive 0.1-10 parts. For example, it can be 0.1, 0.2, 0.3, 0.5, 1, 1.5, 2.0, 2.5, 3.0, 3.5, 4, 5, 6, 6.5, 7, 8, 9 and 10 parts, etc.

[0078] From the above, the photopolymer type holographic recording medium containing optical monomer proposed in the application can realize full cooperation of each component by reasonably controlling the adding amount of each component, without causing the holographic performance of the finally generated photopolymer type holographic recording medium to be poor due to too much or too little of a certain component, and ensuring the comprehensive holographic performance of the final photopolymer type holographic recording medium to be better.

[0079] For example, by controlling the compound with multiple isocyanate reactive functional groups to be 15-40 parts and the polyisocyanate-based compound to be 15-40 parts, the first component and the second component jointly form a film-forming resin with a relatively low refractive index, thereby providing support for other components. In some specific examples, the compound with multiple isocyanate reactive functional groups is further controlled to be 15-35 parts, and the polyisocyanate-based compound is further controlled to be 15-35 parts.

[0080] By controlling the optical monomer to be 1-30 parts and the polymerizable monomer to be 10-40 parts, the third component and the fourth component are the system of writing monomers, and the intermolecular bonding refractive index after polymerization will be higher, so the interaction of the above four components can realize that the photopolymer type holographic recording medium has high refractive index components and low refractive index components with large refractive index difference, and form 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 component and the fourth component) are consumed and the concentration is reduced, and the monomers in the dark area hardly react. The difference in monomer concentration between the bright area and the dark area promotes the high-concentration monomers in the dark area to migrate to the bright area, and the film-forming resin components (such as the first component and the second component) in the bright area are extruded to the dark area, so that the refractive index of the bright area approaches the refractive index of the third component and the fourth component, and the refractive index of the dark area approaches the refractive index of the first component and the second component, forming a phase type volume holographic grating with refractive index modulation. In some specific examples, the optical monomer is further controlled to be 3-20 parts; the polymerizable monomer is further controlled to be 20-35 parts.

[0081] For example, by controlling the photosensitive initiation combination agent to be 0.1-3 parts, a suitable number of photons can be absorbed during exposure, and the polymerization reaction can be controlled at a certain speed, so that the grating can also be quickly formed and a higher diffraction efficiency can be obtained; in addition, it can also ensure that the final holographic recording medium has the required light transmittance, and ensure that the grating has a certain diffraction efficiency. In some specific examples, the photosensitive initiation combination agent is 0.3-2 parts.

[0082] For example, the chain transfer agent is controlled in 0.1-3 parts, which can control the polymer chain length in a reasonable range, effectively prevent the polymerization degree from being too high, and ensure that the final holographic recording medium has the required optical performance and diffraction efficiency. In some specific examples, the chain transfer agent is further controlled in 0.5-2 parts.

[0083] For example, the catalyst is controlled in 0.1-5 parts, which can effectively improve the reaction rate of the related components, improve the consumption rate of the related components after exposure, and quickly form the concentration difference of the monomers of the bright area and the dark area to realize the phase-type volume holographic grating of refractive index modulation. In some specific examples, the catalyst is further controlled in 0.5-3 parts.

[0084] For example, the additive is controlled in 0.1-10 parts, and the additive is taken as a leveling agent for example, which can effectively improve the uniformity of the mixed solution, improve the flowability, and reasonably control the cost. In some specific examples, the additive is further controlled in 0.6-7 parts.

[0085] In some optional examples, the photopolymer type holographic recording medium containing an optical monomer includes the following components in parts by weight: a first component, a compound having a plurality of isocyanate reactive functional groups, 15 parts; a second component, a polyisocyanate-based compound, 30 parts; a third component, an optical monomer, 30 parts; a fourth component, a polymerizable monomer, 21 parts; a fifth component, a photosensitive initiation combination agent, 1 part; a sixth component, a chain transfer agent, 1 part; a seventh component, a catalyst, 0.7 parts; and an eighth component, an additive, 1.3 parts.

[0086] In some optional examples, the photopolymer type holographic recording medium containing an optical monomer includes the following components in parts by weight: a first component, a compound having a plurality of isocyanate reactive functional groups, 20 parts; a second component, a polyisocyanate-based compound, 35 parts; a third component, an optical monomer, 5 parts; a fourth component, a polymerizable monomer, 24 parts; a fifth component, a photosensitive initiation combination agent, 3 parts; a sixth component, a chain transfer agent, 3 parts; a seventh component, a catalyst, 3 parts; and an eighth component, an additive, 7 parts.

[0087] In some optional examples, the photopolymer type holographic recording medium containing an optical monomer includes the following components in parts by weight: a first component, a compound having a plurality of isocyanate reactive functional groups, 40 parts; a second component, a polyisocyanate-based compound, 15 parts; a third component, an optical monomer, 3 parts; a fourth component, a polymerizable monomer, 34 parts; a fifth component, a photosensitive initiation combination agent, 1 part; a sixth component, a chain transfer agent, 1 part; a seventh component, a catalyst, 2 parts; and an eighth component, an additive, 6 parts.

[0088] In some alternative examples, a photopolymer type holographic recording medium containing an optical monomer includes the following components in parts by weight: a first component - a compound having a plurality of isocyanate reactive functional groups 35 parts, a second component - a polyisocyanate based compound 15 parts, a third component - an optical monomer 1 part, a fourth component - a polymerizable monomer 29 parts, a fifth component - a photosensitive initiating combination agent 3 parts, a sixth component - a chain transfer agent 3 parts, a seventh component - a catalyst 5 parts, an eighth component - an additive 9 parts.

[0089] In some alternative examples, a photopolymer type holographic recording medium containing an optical monomer includes the following components in parts by weight: a first component - a compound having a plurality of isocyanate reactive functional groups 30 parts, a second component - a polyisocyanate based compound 17 parts, a third component - an optical monomer 15 parts, a fourth component - a polymerizable monomer 24 parts, a fifth component - a photosensitive initiating combination agent 1 part, a sixth component - a chain transfer agent 1 part, a seventh component - a catalyst 2 parts, an eighth component - an additive 10 parts.

[0090] In some alternative examples, a photopolymer type holographic recording medium containing an optical monomer includes the following components in parts by weight: a first component - a compound having a plurality of isocyanate reactive functional groups 29 parts, a second component - a polyisocyanate based compound 16 parts, a third component - an optical monomer 30 parts, a fourth component - a polymerizable monomer 13 parts, a fifth component - a photosensitive initiating combination agent 2.9 parts, a sixth component - a chain transfer agent 0.1 parts, a seventh component - a catalyst 2 parts, an eighth component - an additive 7 parts.

[0091] In some alternative examples, a photopolymer type holographic recording medium containing an optical monomer includes the following components in parts by weight: a first component - a compound having a plurality of isocyanate reactive functional groups 33 parts, a second component - a polyisocyanate based compound 18 parts, a third component - an optical monomer 35 parts, a fourth component - a polymerizable monomer 11 parts, a fifth component - a photosensitive initiating combination agent 1 part, a sixth component - a chain transfer agent 1 part, a seventh component - a catalyst 0.1 parts, an eighth component - an additive 0.9 parts.

[0092] In some alternative examples, a photopolymer type holographic recording medium containing an optical monomer includes the following components in parts by weight: a first component - a compound having a plurality of isocyanate reactive functional groups 26 parts, a second component - a polyisocyanate based compound 30 parts, a third component - an optical monomer 21 parts, a fourth component - a polymerizable monomer 13 parts, a fifth component - a photosensitive initiating combination agent 0.2 parts, a sixth component - a chain transfer agent 0.8 parts, a seventh component - a catalyst 3 parts, an eighth component - an additive 6 parts.

[0093] In some alternative examples, the photopolymer type holographic recording medium containing an optical monomer includes the following components by weight: a first component - a compound having multiple isocyanate reactive functional groups 35 parts, a second component - a polyisocyanate based compound 15 parts, a third component - an optical monomer 22 parts, a fourth component - a polymerizable monomer 27.6 parts, a fifth component - a photosensitive initiation combination agent 0.1 parts, a sixth component - a chain transfer agent 0.1 parts, a seventh component - a catalyst 0.1 parts, an eighth component - an additive 0.1 parts.

[0094] In some examples of the present application, the compound having multiple isocyanate reactive functional groups, the isocyanate reactive functional groups are hydroxyl groups. Hydroxyl groups are polar groups, in which the alcoholic hydroxyl is easily oxidized, and has a high reactivity. For example, in specific examples, the compound having multiple isocyanate reactive functional groups is a compound having a refractive index less than 1.5 and having two or more hydroxyl functional groups.

[0095] More specifically, the compound having multiple isocyanate reactive functional groups is selected from at least one of tetraethylene glycol, trimethylolethane, glycerol, triethanolamine, polyester polyol having a molecular weight of 200-2000, polycarbonate polyol, polyether polyol. The refractive index of these substances is also low, for example: the refractive index of tetraethylene glycol is 1.46 (20°C); the refractive index of trimethylolethane is 1.5; the refractive index of glycerol is 1.474 (20°C); the refractive index of triethanolamine is 1.482-1.485 (20°C). In some specific examples, the polyether polyol includes polytetrahydrofuran 2000.

[0096] In some examples of the present application, the polyisocyanate based compound is a compound having a refractive index less than 1.5 and having two or more isocyanate groups.

[0097] 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)tris(hexamethylene) isocyanate, 1,4-diisocyanatobutane, butane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate. The refractive index of these compounds is also low, the refractive index of hexamethylene diisocyanate is 1.453; the refractive index of trimethylhexamethylene diisocyanate is 1.462; the refractive index of (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl)tris(hexamethylene) isocyanate is 1.472; the refractive index of butane-1,4-diisocyanate is 1.453; the refractive index of isophorone diisocyanate is 1.484; the refractive index of dicyclohexylmethane diisocyanate is 1.496 (25°C).

[0098] In some examples of the application, the polymerizable monomer is selected from at least one of an alkenyl naphthalene compound, an alkenyl anthracene compound, an alkenyl benzene compound, an acrylic acid compound, a methacrylic acid compound, an acrylate compound, a methacrylate compound, N-vinylpyrrole, N-vinylcarbazole, N-vinylimidazole, N-vinylindole, N-vinylpyrrolidone, trans-N-3-alkynylbutenylcarbazole.

[0099] In specific examples, the alkenyl naphthalene compound is selected from at least one of 1-vinyl naphthalene, 2-vinyl naphthalene.

[0100] In specific examples, the alkenyl anthracene compound is selected from at least one of 2-vinyl anthracene, 9-vinyl anthracene.

[0101] In specific examples, the alkenyl benzene compound is selected from at least one of styrene, 2-chlorostyrene, 2-bromostyrene, 3-chlorostyrene, 3-bromostyrene, 4-chlorostyrene, 4-bromostyrene, p-(chloromethyl)styrene, p-(bromomethyl)styrene.

[0102] In specific examples, the methacrylic acid compound includes at least one of methacrylic acid and derivatives thereof.

[0103] 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-bis(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-diyl bis[(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.

[0104] In specific examples, the methacrylate compound is 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-bis(2-thionaphthyl) 2-butyl methacrylate, pentabromobenzyl methacrylate, 2-naphthyl methacrylate, bisphenol A dimethacrylate, tetrabromobisphenol A dimethacrylate.

[0105] In some examples of the present application, the photosensitive initiation combination agent comprises a photosensitizer and a photoinitiator. The photosensitizer therein can be matched with the photoinitiator to realize a visible light initiation system and adapt to different wavelengths of lasers. Under irradiation of light in a specific wavelength range, the photosensitizer in the photoinitiation system is activated by the corresponding light and absorbs light energy, which is transmitted to the photoinitiator, so that the photoinitiator can be activated under irradiation of light in a more wavelength range, generating free radicals with initiation function. The photoinitiating free radicals can initiate monomer polymerization to realize the construction of holographic gratings, improve the photosensitivity of photopolymer type holographic recording medium, and broaden the optional range of radiation sources of light radiation.

[0106] Therefore, it can be understood that in other examples, when the present application adopts a photoinitiator adapted to a wavelength, the photosensitizer can not be added.

[0107] When the photosensitive initiation combination agent simultaneously comprises a photosensitizer and a photoinitiator, further, the mass ratio of the photosensitizer and the photoinitiator is (0.001-1):(0.1-3). By controlling the mass ratio of the photosensitizer to the photoinitiator in the above range, the concentration of the photosensitizer can be effectively controlled, so that the number of absorbed photons is controlled in a suitable range during holographic exposure, the speed of polymerization reaction is controlled in a reasonable range, and the speed of grating formation is controlled in a certain range, ensuring the light transmittance of the photopolymer type holographic recording medium and obtaining excellent diffraction efficiency. In more specific examples, the mass of the photosensitizer is 1 / 10-1 / 3 of the mass of the photoinitiator, for example, 1 / 10, 1 / 9, 1 / 8, 1 / 7, 1 / 6, 1 / 5, 1 / 4 or 1 / 3, etc.

[0108] In the present application, different wide-band responses can be realized by regulating the type of photosensitizer. For example, the photosensitizer is a dye with high electron transfer efficiency under light.

[0109] In specific examples, 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 cycloalkanone compounds.

[0110] More specifically, the photosensitizer is selected from one or more of neomethylene blue (maximum absorption wavelength 666 nm), thionine (absorption wavelength 602.5 nm), basic yellow (absorption wavelength 412 nm), pinacylchloride, rhodamine 6G (absorption wavelength 400 nm to 700 nm), malachite green, ethyl violet (absorption wavelength 596 nm), victoria blue R (maximum absorption wavelength 615 nm), lapis lazuli blue (absorption wavelength 630 to 640 nm), methylene blue (maximum absorption wavelength 662 nm), basic orange, darrow red (maximum absorption wavelength 502 nm), pyrrole red Y (strong absorption wavelengths are 235 nm, 267 nm, 336 nm, 515 nm), basic red 29, quinaldine red (maximum absorption wavelength 528 nm), crystal violet (absorption wavelength 588 nm to 592 nm), ethyl violet (maximum absorption wavelength 596 nm), brilliant green (maximum absorption wavelength 630 nm), azure A (maximum absorption wavelength 633 nm), crystal violet lactone (maximum absorption wavelength 579 nm), malachite green lactone, eosin (absorption wavelength 510 nm to 518 nm).

[0111] In a specific example, the photoinitiator is selected from at least one of aromatic ketone compounds, benzoin and its derivatives, benzil ketals, acylphosphine oxides, arylborate ammonium salts, chromium salts, aryl diazonium salts, onium salts, organometallic compounds. Other photoinitiators with similar functions can also be used, which are not limited in the present application. The photoinitiator of the present application can be activated by actinic radiation and initiate the polymerization reaction of the corresponding polymerizable groups.

[0112] More specifically, the photoinitiator is selected from one or more of benzophenone (absorption wavelength 210 nm, 255 nm), alkylbenzophenone (290 nm-360 nm), 4,4'-bis(dimethylamino)benzophenone, anthrone (299 nm-366 nm) and halogenated benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide (absorption wavelength 350 nm-400 nm), bisacylphosphine oxide, phenyldihydroxyacetophenone, camphorquinone (absorption wavelength 400 nm-500 nm), a-aminoalkylphenone (absorption wavelength 380 nm-430 nm), a,a-dialkoxyacetophenone, a-hydroxyalkylphenone (absorption wavelength 320 nm-380 nm), tetrabutylammonium triphenylhexylborate, tetrabutylammonium tris(3-fluorophenyl)hexylborate, tetrabutylammonium tris(3-chloro-4-methylphenyl)hexylborate, ferrocenyl compounds, iodonium salts, sulfonium salts, hexaarylbiimidazole, and the like. When these photoinitiators are irradiated with light in the corresponding wavelength range, they can be rapidly activated and generate active radicals, thereby initiating the polymerization reaction between the components of the photopolymer type holographic recording medium, achieving the difference in monomer concentration between the bright and dark regions. Alternatively, when the photosensitizer coordinated therewith transmits heat to the photoinitiator after absorbing light in the corresponding wavelength range, the activation of the photoinitiator is achieved.

[0113] In some examples of the present application, the chain transfer agent is a thiol compound.

[0114] In specific examples, the chain transfer agent includes one or more of dodecanethiol, mercaptoethanol, hexanethiol, phenylethylthiol, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, 4-methyl-4H-1,2,4-triazole-3-thiol, and the like.

[0115] In some examples of the present application, the catalyst is a tertiary amine catalyst or an organometallic catalyst.

[0116] In specific examples, the catalyst is selected from at least one of triethylenediamine, bis(dimethylaminoethyl) ether, dimethylethanolamine, 2-(2-dimethylamino-ethoxy)ethanol, trimethylhydroxyethylpropylenediamine, N,N-bis(dimethylaminopropyl)isopropanolamine, dibutyltin dilaurate, stannous octoate, potassium carboxylate catalysts, and bismuth carboxylate catalysts. The catalyst is not limited to the above-listed types, as long as it can achieve the catalysis of the polymerization of the relevant components under light, as will be understood by those skilled in the art, which falls within the scope of the present application.

[0117] In some examples of the present application, the additive includes one or more of a defoaming agent, a leveling agent, a water removal agent, and a plasticizer.

[0118] In specific examples, the defoaming agent is a silicone defoaming agent and / or a non-silicone polymeric defoaming agent, and the defoaming agent accounts for less than or equal to 3% by weight of the photopolymer type holographic recording medium. The defoaming agent can reduce the surface tension of the liquid and remove bubbles, and improve the flowability of the mixture of components.

[0119] More specifically, for example, BYK-011, BYK-012, BYK-014, BYK-023, BYK-051N, BYK-085, BYK-1610, BYK-1707, BYK-1740, BYK-1760 produced by BYK, DC65, AFE-7820 produced by Dow Corning, or any proportion mixture of these defoaming agents. The defoaming agents of the BYK series have excellent defoaming performance, good compatibility with other components, and good dispersibility; among them, BYK-011, BYK-012, BYK-014, and BYK-051N are non-silicone polymeric defoaming agents. DC65 is a water-based ink, which dries quickly, has good printing effect, and is not easy to fall off. AFE-7820 has high defoaming performance.

[0120] In specific examples, the leveling agent is a silicone surface agent, and the leveling agent accounts for less than or equal to 3% by weight of the photopolymer type holographic recording medium. For example, BYK-302, BYK-306, BYK-307, BYK-327, BYK-329, BYK-333, BYK-356, BYK-358, BYK-378, BYK-3455, BYK-3566 produced by BYK, or any proportion mixture of these surface agents. The leveling agents of the BYK series have excellent leveling performance.

[0121] In specific examples, the plasticizer accounts for less than or equal to 3% by weight of the photopolymer type holographic recording medium. The plasticizer is toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, phthalate, or any proportion mixture of these compounds.

[0122] In other embodiments, the additive further includes a water removal agent. The water removal agent is selected from methylbenzenesulfonylisocyanate, triethyl orthoformate, CUWR-WB20 water removal agent produced by Guangzhou Yourun Synthetic Material Co., Ltd., ALT-201 water removal agent produced by Anxiang Ailite Chemical Co., Ltd., PCCI water removal agent produced by Shanghai Ru'er Chemical Industry Trade Co., Ltd., and the like.

[0123] In some examples, the water removal agent accounts for less than or equal to 3% by weight of the photopolymer type holographic recording medium. The water removal agent can remove excess water in the reaction, so that the components are mixed better and do not appear to be layered.

[0124] The application of the photopolymer type holographic recording medium containing optical monomers of the present application is described below.

[0125] The holographic optical element includes, but is not limited to, a volume holographic grating.

[0126] As can be seen from the above, the holographic optical element has the advantages of the photopolymer type holographic recording medium, i.e., high diffraction efficiency, high sensitivity, and small required exposure amount.

[0127] The optical device includes, but is not limited to, a head-up display (HUD), an augmented reality device (AR device), a virtual reality device (VR device), and a photopolymer type holographic storage optical disc. The photopolymer type holographic storage optical disc can realize erasable and rewritable and real-time recording, is suitable for storing a large amount of data, and has a very fast data transmission speed.

[0128] As can be seen from the above, the optical device has the advantages of the holographic optical element, i.e., excellent holographic performance of the optical device, a clear picture of the optical device, and the ability to store a large amount of data.

[0129] The optical monomer, the preparation method of the optical monomer, and the photopolymer type holographic recording medium containing the optical monomer are described below in combination with specific embodiments.

[0130] Embodiment 1

[0131] The structural formula of the optical monomer in this embodiment is as follows: The optical monomer is denoted as G1-1.

[0132] The preparation method of the optical monomer with the structural formula G1-1 includes the following steps:

[0133] Step S1: compounds P1-1 (in the structural formula of P1-1, R3 is hydrogen, and R4 is Br), a coupling catalyst tetrakis(triphenylphosphine)palladium, a ligand triphenylphosphine, an alkali sodium carbonate, and a compound P2-1 (4-hydroxyethylthio phenylboronic acid) are dissolved in a first solvent toluene, heated to 60°C and stirred for reaction for 24 h, toluene is removed by rotary evaporation, and column chromatography is performed to separate to obtain a compound P3-1 (in the structural formula of P3-1, R5 is H, and R6 is a group with the structural formula The equivalent ratio of the coupling catalyst, the ligand, the alkali, the compound P1-1, and the compound P2-1 is 0.005:0.01:1:1:1.1. The reaction equation is represented as follows:

[0134]

[0135] Step S2: Compound P3-1 was dissolved in a second solvent ethanol with a deacidifying agent triethylamine under ice bath, stirring and adding compound M2 acryloyl chloride until complete reaction, removing excess acryloyl chloride, post-treatment and separation to obtain an optical monomer with structural formula G1-1; the equivalent ratio of compound P3-1, deacidifying agent, compound M2 was 1:2:1.9. The reaction equation is shown as follows:

[0136]

[0137] The characterization data of optical monomer G1-1 are as follows:

[0138] 1 H NMR (600 MHz, CDCl3) δ 8.36-8.31 (m, 1H), 8.12 (dd, J = 7.4, 1.6 Hz, 1H), 7.81 (dd, J = 7.6, 1.5 Hz, 1H), 7.58-7.51 (m, 3H), 7.50-7.40 (m, 2H), 7.36 (td, J = 7.4, 1.5 Hz, 1H), 7.31-7.25 (m, 2H), 6.09 (dd, J = 16.5, 10.3 Hz, 1H), 5.90-5.81 (m, 2H), 4.31 (t, J = 7.1 Hz, 2H), 3.27 (t, J = 7.1 Hz, 2H).

[0139] 13 C NMR (151 MHz, CDCl3) δ 166.16, 140.04, 139.59, 134.90, 134.02, 133.95, 132.34, 131.45, 128.79, 128.40, 128.31, 128.30, 126.26, 125.72, 125.62, 123.61, 123.09, 64.76, 33.66.

[0140] In other embodiments, under the condition that other conditions are the same, when the compound M2 in step S2 in embodiment 1 is replaced by methacryloyl chloride, an optical monomer G1-2 containing a methacrylate group can be obtained, and the preparation method is not described here.

[0141] Embodiment 2

[0142] The structural formula of the optical monomer in this embodiment is The optical monomer is denoted as G2-1.

[0143] The preparation method of the optical monomer with structural formula G2-1 includes the following steps:

[0144] Step S1: Compound P1-2 (wherein R3 in the structural formula of P1-2 is hydrogen, and R4 is Br), coupling catalyst bis(diphenylphosphinoferrocene)palladium dichloride, ligand 2,2'-bis(diphenylphosphino)-1,1'-binaphthalene, base, potassium fluoride compound P2-2 is 4-hydroxyethylsulfanylphenylboronic acid are dissolved in the first solvent acetonitrile, heated to 70°C and stirred for 20h, acetonitrile is removed by rotary evaporation and column chromatography to obtain compound P3-2 (wherein R5 in the structural formula of P3-2 is H, and R6 is a group with the structural formula The equivalent ratio of coupling catalyst, ligand, base, compound P1-2 and compound P2-2 is 0.01:0.03:2:1:1.1. The reaction equation is represented as follows:

[0145]

[0146] Step S2: Compound P3-2 is dissolved in the second solvent ethanol with acid binding agent triethylamine under ice bath, stirred and compound M2 methyl acryloyl chloride is added until complete reaction, excess methyl acryloyl chloride is removed, post-treated and separated to obtain optical monomer with the structural formula G2-1; the equivalent ratio of compound P3-1, acid binding agent, compound M2 is 1:2:1.7. The reaction equation is represented as follows:

[0147]

[0148] The characterization data of optical monomer G2-1 are as follows:

[0149] 1 H NMR (600 MHz, CDCl3) δ 8.19 (dd, J = 7.5, 1.4 Hz, 1H), 7.81 (ddd, J = 7.4, 5.5, 1.6 Hz, 2H), 7.60-7.54 (m, 2H), 7.50 (dd, J = 7.5, 1.7 Hz, 1H), 7.47-7.41 (m, 2H), 7.36 (td, J = 7.5, 1.6 Hz, 1H), 7.36-7.30 (m, 2H), 5.95 (dq, J = 2.0, 1.0 Hz, 1H), 5.63 (dq, J = 2.1, 1.1 Hz, 1H), 4.31 (t, J = 7.1 Hz, 2H), 3.30 (t, J = 7.1 Hz, 2H), 1.95 (t, J = 1.0 Hz, 3H).

[0150] 13C NMR (151 MHz, CDCI3) δ 167.45, 138.55, 137.87, 137.54, 136.06, 135.51, 134.13, 128.60, 128.54, 128.19, 126.11, 125.87, 124.51, 123.52, 122.58, 122.28, 65.85, 33.61, 18.24.

[0151] In other embodiments, under the condition that other conditions remain the same, when the compound M2 in step S2 in embodiment 2 is replaced by acryloyl chloride, an optical monomer G2-2 containing an acrylate group can be obtained, the preparation method of which is not described here.

[0152] Embodiment 3

[0153] The structural formula of the optical monomer in this embodiment is The optical monomer is denoted as G3-1.

[0154] The preparation method of the optical monomer with the structural formula G3-1 comprises the following steps:

[0155] Step S1: dissolve compound P1-3 (in the structural formula of P1-3, R3 is hydrogen and R4 is Br), coupling catalyst palladium acetate, ligand 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl, base barium hydroxide, compound P2-3 which is 4-hydroxyethylsulfanylphenylboronic acid in the first solvent tetrahydrofuran, heat at 80°C and stir for reaction for 17h, remove tetrahydrofuran by rotary evaporation and separate by column chromatography to obtain compound P3-3 (in the structural formula of P3-3, R5 is H and R6 is a group with the structural formula The equivalent ratio of coupling catalyst, ligand, base, compound P1-3 and compound P2-3 is 0.01:0.02:1.20:1:1.3. The reaction equation is represented as follows:

[0156]

[0157] Step S2: dissolve compound P3-3 and acid-binding agent triethylamine in the second solvent ethanol under ice bath, stir and add compound M2 acryloyl chloride until complete reaction, remove excess acryloyl chloride, perform post-treatment and separate to obtain the optical monomer with the structural formula G3-1; the equivalent ratio of compound P3-3, acid-binding agent and compound M2 is 1:2:1.5. The reaction equation is represented as follows:

[0158] The characterization data of the optical monomer G3-1 are as follows:

[0159] 1H NMR (600 MHz, CDC13) δ 8.36 - 8.31 (m, 1H), 8.20 (d, J = 7.6 Hz, 1H), 8.00 (d, J = 1.5 Hz, 1H), 7.80 (dd, J = 7.5, 1.5 Hz, 1H), 7.74 (dd, J = 7.4, 1.5 Hz, 1H), 7.54 - 7.48 (m, 2H), 7.46 (td, J = 7.5, 1.5 Hz, 1H), 7.38 - 7.31 (m, 3H), 6.14 - 6.05 (m, 1H), 5.89 - 5.83 (m, 2H), 4.31 (t, J = 7.1 Hz, 2H), 3.27 (t, J = 7.1 Hz, 2H).

[0160] 13 C NMR (151 MHz, CDC13) δ 166.16, 140.00, 139.40, 138.49, 137.06, 135.48, 133.55, 131.43, 128.31, 128.30, 128.15, 127.93, 127.15, 125.69, 124.20, 123.59, 122.97, 121.56, 64.78, 33.66.

[0161] In other embodiments, under the condition that other conditions remain unchanged, when the compound M2 in step S2 in Example 3 is replaced by methacryloyl chloride, an optical monomer G3-2 containing a methacrylate group can be obtained, and the preparation method is not described here.

[0162] Example 4

[0163] The structural formula of the optical monomer in this example is The optical monomer is denoted as G4-1.

[0164] The preparation method of the optical monomer with the structural formula G4-1 includes the following steps:

[0165] Step S1: compound P1-4 (in the structural formula of P1-4, R3 is hydrogen, and R4 is Br), coupling catalyst bis(triphenylphosphine)palladium dichloride, ligand 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-yl, base potassium trimethylsilanolate, compound P2-4 which is 4-hydroxyethylthio phenylboronic acid are dissolved in the first solvent dioxane, heated to 90°C and stirred for 10h, rotary evaporation to remove dioxane and column chromatography to obtain compound P3-4 (in the structural formula of P3-4, R5 is H, and R6 is a group with the structural formula The equivalent ratio of the coupling catalyst, the ligand, the base, the compound P1-4 and the compound P2-4 is 0.02:0.04:1.30:1:1.2. The reaction equation is represented as follows:

[0166]

[0167] Step S2: Compound P3-4 was dissolved in a second solvent ethanol with a deacidifying agent triethylamine under ice bath, stirring and adding compound M2 methacryloyl chloride until complete reaction, removing excess methacryloyl chloride, post-treatment and separation to obtain an optical monomer with structural formula G4-1; the equivalent ratio of compound P3-4, deacidifying agent, compound M2 was 1:2:1.6. The reaction equation is shown as follows:

[0168]

[0169] The characterization data of optical monomer G4-1 are as follows:

[0170] 1 H NMR (600 MHz, CDCl3) δ 8.30 (dd, J = 7.5, 1.8 Hz, 1H), 8.12 (d, J = 1.6 Hz, 1H), 8.02 (d, J = 7.5 Hz, 1H), 7.74 (dd, J = 7.4, 1.5 Hz, 1H), 7.53-7.45 (m, 4H), 7.38-7.29 (m, 3H), 5.95 (dq, J = 2.1, 1.0 Hz, 1H), 5.63 (dq, J = 2.1, 1.1 Hz, 1H), 4.31 (t, J = 7.1 Hz, 2H), 3.30 (t, J = 7.1 Hz, 2H), 1.95 (t, J = 1.0 Hz, 3H).

[0171] 13 C NMR (151 MHz, CDCl3) δ 167.42, 140.04, 139.27, 138.54, 136.06, 134.75, 134.17, 128.74, 128.35, 128.08, 126.11, 125.37, 124.84, 123.85, 122.97, 122.86, 121.07, 65.84, 33.60, 18.24.

[0172] In other embodiments, under the condition that other conditions are the same, when compound M2 in step S2 in embodiment 4 is replaced by acryloyl chloride, an optical monomer G4-2 containing an acrylate group can be obtained, and the preparation method is not described here.

[0173] Embodiment 5

[0174] The structural formula of the optical monomer in this embodiment is The optical monomer is denoted as G5-1.

[0175] The preparation method of the optical monomer with the structural formula of G5-1 comprises the following steps:

[0176] Step S1: compound P1-5 (in the structural formula of P1-5, R3 is Br, and R4 is Br), a coupling catalyst tris(dibenzylideneacetone)dipalladium, a ligand 1,1'-bis(diphenylphosphino)ferrocene, a base tetrabutylammonium fluoride, compound P2-5 which is 4-hydroxyethylsulfanylphenylboronic acid are dissolved in a first solvent dimethyl sulfoxide, heated at 100 DEG C and stirred to react for 5 h, dimethyl sulfoxide is removed by rotary evaporation, and column chromatography is performed to separate to obtain compound P3-5 (in the structural formula of P3-5, R5 is a group with the structural formula of , and R6 is a group with the structural formula of ); the equivalent ratio of the coupling catalyst, the ligand, the base, compound P1-5 and compound P2-5 is 0.03:0.07:2:1:2.2. The reaction equation is shown as follows:

[0177]

[0178] Step S2: compound P3-5 is dissolved in a second solvent ethanol under ice bath, a deacidifying agent triethylamine is added, stirring is performed, compound M2 acryloyl chloride is added until complete reaction, excess acryloyl chloride is removed, post-treatment is performed, and separation is performed to obtain the optical monomer with the structural formula of G5-1; the equivalent ratio of compound P3-5, the deacidifying agent and compound M2 is 1:2:1.8. The reaction equation is shown as follows:

[0179]

[0180] The characterization data of the optical monomer G5-1 are as follows:

[0181] 1 H NMR (600 MHz, CDCl3) δ 8.33 (d, J = 1.5 Hz, 1H), 8.00 (d, J = 7.5 Hz, 1H), 7.52-7.46 (m, 2H), 7.37 (dd, J = 7.5, 1.5 Hz, 1H), 7.33-7.27 (m, 2H), 6.14-6.05 (m, 1H), 5.86 (dd, J = 13.3, 0.8 Hz, 2H), 4.30 (t, J = 7.1 Hz, 2H), 3.28 (t, J = 7.1 Hz, 2H).

[0182] 13 C NMR (151 MHz, CDCl3) δ 166.40, 139.89, 138.76, 136.34, 134.81, 131.47, 129.14, 128.18, 127.91, 124.73, 123.96, 121.22, 65.79, 33.52.

[0183] In other embodiments, under other conditions, when the compound M2 in step S2 in Example 5 is replaced by methacryloyl chloride, an optical monomer G5-2 containing a methacrylate group can be obtained, and the preparation method is not described here.

[0184] Example 6

[0185] The structural formula of the optical monomer in this example is The optical monomer is denoted as G6-1.

[0186] The preparation method of the optical monomer with the structural formula G6-1 includes the following steps:

[0187] Step S1: Compound P1-6 (wherein R3 in the structural formula of P1-6 is Br, and R4 is Br), coupling catalyst bis(triphenylphosphine)palladium dichloride, ligand 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-yl, base sodium hydroxide, compound P2-6 is 4-hydroxyethylthio phenylboronic acid are dissolved in the first solvent N,N-dimethylformamide, heated to 110°C and stirred for 3h, N,N-dimethylformamide is removed by rotary evaporation and separated by column chromatography to obtain compound P3-6 (wherein R5 in the structural formula of P3-6 is a group with the structural formula , and R6 is a group with the structural formula ); the equivalent ratio of compound coupling catalyst, ligand, base, P1-6 and compound P2-6 is 0.04:0.08:2.55:1:2.2. The reaction equation is represented as follows:

[0188]

[0189] Step S2: Compound P3-6 is dissolved in the second solvent ethanol with acid binding agent triethylamine under ice bath, stirred and compound M2 methacryloyl chloride is added until complete reaction, excess methacryloyl chloride is removed, post-treated and separated to obtain the optical monomer with the structural formula G6-1; the equivalent ratio of compound P3-6, acid binding agent, compound M2 is 1:2:3. The reaction equation is represented as follows:

[0190]

[0191] The characterization data of the optical monomer G6-1 are as follows:

[0192] 1H NMR (600 MHz, CDC13) δ 8.12 (dd, J = 6.6, 2.3 Hz, 1H), 7.55 - 7.47 (m, 4H), 7.30 - 7.24 (m, 2H), 5.96 (ddt, J = 7.7, 1.8, 1.0 Hz, 1H), 5.61 (ddq, J = 15.4, 2.0, 1.1 Hz, 1H), 4.29 (t, J = 7.1 Hz, 2H), 3.30 (t, J = 7.1 Hz, 2H), 1.94 (t, J = 1.0 Hz, 3H).

[0193] 13 C NMR (151 MHz, CDC13) δ 167.38, 140.54, 136.60, 136.18, 135.04, 133.95, 133.31, 129.44, 128.20, 126.29, 126.10, 125.03, 122.73, 65.98, 33.46, 18.27.7.

[0194] In other embodiments, under other conditions, when the compound M2 in step S2 in Example 6 is replaced by acryloyl chloride, an optical monomer G6-2 containing an acrylate group can be obtained, the preparation method is not described here.

[0195] Example 7

[0196] The structural formula of the optical monomer in this example is The optical monomer is denoted as G7-1.

[0197] Step S1: compound P1-7 (wherein R3 in the structural formula of P1-7 is Br, and R4 is Br), coupling catalyst Bedford palladium catalyst, ligand 2,2'-bis(diphenylphosphino)-1,1'-binaphthalene, base cesium carbonate, compound P2-7 is 4-hydroxyethylsulfanylphenylboronic acid are dissolved in the first solvent dimethyl sulfoxide, heated to 120°C and stirred for 2h, rotary evaporation to remove dimethyl sulfoxide and separation to obtain compound P3-7 (wherein R5 in the structural formula of P3-7 is a group with the structural formula , and R6 is a group with the structural formula ); the equivalent ratio of coupling catalyst, ligand, base, compound P1-7 and compound P2-7 is 0.05:0.1:3:1:2.5. The reaction equation is represented as follows:

[0198]

[0199] Step S2: compound P3-7 was dissolved in a second solvent ethanol with a base triethylamine under ice bath, compound M2 acryloyl chloride was added to complete the reaction, excess acryloyl chloride was removed, post-treatment was carried out and optical monomer with structural formula G7-1 was separated; the equivalent ratio of compound P3-7, the base and compound M2 was 1:2:3. The reaction equation is shown as follows:

[0200]

[0201] The characterization data of optical monomer G7-1 are as follows:

[0202] 1 H NMR (600 MHz, CDCl3) δ 8.23 (d, J = 7.6 Hz, 1H), 8.00 (d, J = 1.4 Hz, 1H), 7.78 (dd, J = 7.5, 1.4 Hz, 1H), 7.55-7.49 (m, 2H), 7.35-7.29 (m, 2H), 6.14-6.05 (m, 1H), 5.86 (dd, J = 13.3, 0.8 Hz, 2H), 4.30 (t, J = 7.1 Hz, 2H), 3.28 (t, J = 7.1 Hz, 2H).

[0203] 13 C NMR (151 MHz, CDCl3) δ 166.40, 140.70, 138.99, 137.11, 136.34, 135.31, 131.46, 129.14, 128.20, 127.93, 127.10, 123.57, 122.02, 65.78, 33.50.

[0204] In other embodiments, under the condition that other conditions are the same, when compound M2 in step S2 in embodiment 7 is replaced by methacryloyl chloride, optical monomer G7-2 containing a methacrylate group can be obtained, and the preparation method is not described here.

[0205] The specific coupling catalysts, ligands, bases, first solvents, second solvents and base agents described in the embodiments of the present application are only used for illustrative description, and those skilled in the art should understand that other kinds of reagents described in the present application should also be within the protection scope of the present application.

[0206] Embodiment 8

[0207] Photopolymer type holographic recording media 8-1 to 8-7 containing optical monomers in embodiments 1-7 were used: the specific components of photopolymer type holographic recording media 8-1 to 8-7 are shown in Table 1 below.

[0208] Table 1 contains the components of each photopolymer type holographic recording medium of each example of the optical monomer

[0209]

[0210]

[0211] The selection of each component in the present examples can also be other components listed above, and these examples should not be construed as limiting the scope of protection of the present application.

[0212] Comparative Example

[0213] The components of the photopolymer type holographic recording medium 8-1 in Example 8 are substantially the same, except that the optical monomer G1-1 of the photopolymer type holographic recording medium 8-1 is removed, so that the fraction of the optical monomer is changed to 0 parts, and the polymerizable monomer p-bromophenyl methacrylate is increased to 29 parts, and a common photopolymer type holographic recording medium is obtained.

[0214] Test Example 1

[0215] The refractive index of the optical monomers in Examples 1-7 was tested using an Abbe refractometer, and the test results are shown in Table 2 below.

[0216] Table 2 Refractive index test table of optical monomers G1-1 to G1-7

[0217] Optical monomer G1-1 G2-1 G3-1 G4-1 G5-1 G6-1 G7-1 Refractive index 1.73 1.71 1.73 1.71 1.72 1.7 1.72

[0218] It can be seen that the refractive index of the optical monomers of the present application is greater than or equal to 1.7.

[0219] Test Example 2

[0220] The performance of the photopolymer type holographic recording medium 8-1 to 8-7 containing the optical monomers of Example 8 and the common photopolymer holographic recording medium of the comparative example was tested, and the results are shown in Table 3. During testing, each holographic recording medium in Example 8 can be exposed to laser light of different wavelengths according to the different photosensitive systems, and the exposure intensity is 3 mW / cm 2 .

[0221] The corresponding holographic performance graphs of the photopolymer type holographic recording medium 8-1 to 8-4 containing the optical monomers in Example 8 were plotted, and the holographic performance graphs of Figure 1 ; and the corresponding holographic performance graphs of Examples 8-5 to 8-7 were plotted, and the holographic performance graphs of Figure 2 .

[0222] Specifically, for the above five holographic recording mediums 8-1, 8-2, 8-3, 8-4, 8-5, 8-6 and 8-7, solid-state lasers with wavelengths of 633 nm, 610 nm, 457 nm, 633 nm, 532 nm, 633 nm, 610 nm are used as light sources, respectively, and two beams with the same intensity and a diameter of 8 mm are obtained after passing through a beam expander, a beam splitter and a half-wave plate. The two beams intersect in the prepared holographic recording medium for exposure, and the light intensity is 3 mW / cm 2 A 785 nm wavelength solid-state laser that does not react with the recording medium is used as a detection light source, the detection light is incident on the exposure area at the Bragg angle, and the transmitted light and the diffracted light are monitored in real time by a photodetector, and the single-grating diffraction efficiency (η) of the photopolymer type holographic recording medium and the photosensitive sensitivity (S) of the photopolymer type holographic recording medium are calculated by formulas (1) to (3).

[0223]

[0224] In the formula, η is the diffraction efficiency, η max is the highest diffraction efficiency, I d is the diffracted light, I t is the transmitted light, S is the photosensitive sensitivity, E is the exposure energy, and ΔE is the exposure energy when the highest diffraction efficiency is reached.

[0225] As Figure 1 shown, the diffraction efficiency of the photopolymer type holographic recording medium of the present application is greater than 95%, the exposure amount is less than 10 mJ / cm 2 , and the sensitivity is greater than 110 cm / mJ.

[0226] As Figure 3 shown, the ordinary photopolymer type holographic recording medium of the comparative example is exposed, the exposure wavelength is 633 nm, and the exposure light intensity is 3 mW / cm 2 . The diffraction efficiency of the ordinary photopolymer type holographic recording medium of the comparative example is less than 40%, the required exposure amount is greater than 90 mJ / cm 2 , and the sensitivity is less than 10 cm / mJ.

[0227] The holographic performance tests of the photopolymer type holographic recording mediums 8-1 to 8-7 in Example 8 and the ordinary photopolymer type holographic recording medium of the comparative example are shown in Table 3 below.

[0228] Table 3 Holographic performance test table of each photopolymer type holographic recording medium in Example 8 and the comparative example

[0229]

[0230] In summary, referring to Figure 1 ,Figure 2 , Figure 3 and Table 3, the diffraction efficiency of the photopolymer type holographic recording medium of the embodiments of the present application is much higher than that of the comparative examples, the sensitivity is much greater than that of the comparative examples, and the required exposure amount is small. Referring to Table 2, the refractive index of the optical monomer in the embodiments 1-7 of the present application is between 1.70-1.73, which is high. It can be seen that the optical monomer of the present application can have a higher addition amount in the photopolymer, and effectively improves the refractive index of the writing monomer, and further improves the refractive index difference between the writing monomer and the film-forming resin, so that the holographic performance of the photopolymer type holographic recording medium containing the optical monomer of the present application is significantly improved.

[0231] The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of various equivalent modifications or replacements within the technical range disclosed by the present application, and these modifications or replacements should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. An optical monomer characterized by, The structural general formula is as follows: wherein R1and R2are each a group of the formula or wherein one of R1and R2is hydrogen and the other of R1and R2is a group of the formula R0represents hydrogen or methyl.

2. The optical monomer of claim 1, wherein, The optical monomer is selected from monomers with the following structural formula:

3. A method for producing an optical monomer as claimed in claim 1 or 2, characterized in that, The method comprises the following steps: The compound P1, a coupling catalyst, a ligand, a base, and the compound P2 are dissolved in a first solvent, heated and stirred to react, post-treated and separated to obtain the compound P3; the equivalent ratio of the compound P1 to the compound P2 is 1:(1-2); The structural formula of the compound P1 is wherein, R3, R4 are both Br, or one of R3, R4 is H and the other is Br; The structural formula of the compound P2 is The structural formula of the compound P3 is wherein, R5, R6 are both groups with the structural formula or one of R5, R6 is H and the other is a group with the structural formula .

4. The method for preparing the optical monomer as described in claim 3, characterized in that, The method further comprises the following steps: at a second temperature, stirring and adding compound M2 to complete reaction, removing excess reactants, post-treatment and separation to obtain optical monomer with structural formula ; compound M2 is acryloyl chloride or methacryloyl chloride, and the equivalent ratio of compound P3 to compound M2 is 1:(1-3). 5.The method of claim 3, wherein the heating and stirring are performed at a temperature of 60-120℃ for 2-24 hours. The molar ratio of the coupling catalyst, the ligand, the base, and the compound P1 is (0.005-0.05):(0.01-0.1):(1-3):

1. The coupling catalyst is selected from at least one of tetrakis(triphenylphosphine)palladium, bis(diphenylphosphinoferrocene)palladium dichloride, palladium acetate, tris(dibenzylideneacetone)dipalladium, bis(triphenylphosphine)palladium dichloride, palladium chloride containing a di-tert-butylphosphine-based ferrocene ligand, bis(triphenylphosphine)palladium dichloride, bis(diphenylphosphinoferrocene)nickel chloride, palladium on carbon, a Bedford palladium catalyst, a monodentate phosphine ligand catalyst, a palladium catalyst containing a tert-butyl ligand, and a Buchwald pre-catalyst. The ligand is selected from at least one of triphenylphosphine, 2,2'-bis(diphenylphosphino)-1,1'-binaphthyl, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, 2-dicyclohexylphosphino-2',6'-dimethoxybiphenyl, 1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene, tricyclohexylphosphine, and 1,1'-bis(diphenylphosphino)ferrocene. The base is selected from at least one of potassium carbonate, sodium carbonate, cesium carbonate, potassium phosphate, potassium fluoride, cesium fluoride, tetrabutylammonium fluoride, barium hydroxide, sodium hydroxide, and potassium trimethylsilanol. 6.The method of claim 3 or 5, wherein the first solvent is selected from one or more organic solvents, or the first solvent is selected from a mixed solution of at least one organic solvent and water, wherein the organic solvent in the first solvent includes toluene, dimethoxyethane, tetrahydrofuran, N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, dioxane. The heating and stirring are performed at a temperature of 60-120℃ for 2-24 hours. 7.The method of claim 4, wherein the second temperature is the temperature of an ice bath. The equivalent ratio of the compound P3 to the acid-binding agent is 1:(1-4). The acid-binding agent is selected from at least one of triethylamine, pyridine, N,N-diisopropylethylamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, potassium carbonate, ammonium carbonate, and sodium carbonate. The second solvent is selected from at least one of ethanol, petroleum ether, dichloromethane, trichloromethane, ethyl acetate, tetrahydrofuran, acetonitrile, N,N-dimethylformamide, and dimethyl sulfoxide. The removal of the excess reactants includes removing the excess compound M2 by adding dilute hydrochloric acid dropwise.

8. The method for preparing an optical monomer according to claim 4 or 7, wherein ​ ​ 9. A photopolymer type holographic recording medium, characterized by, The writing monomer includes an optical monomer and a polymerizable monomer, the optical monomer is the optical monomer of claim 1 or 2; and / or, the optical monomer is prepared by the preparation method of the optical monomer of any one of claims 3-8.

10. The photopolymer type holographic recording medium according to claim 9, wherein The writing monomer accounts for 11-70% of the weight percentage of the entire photopolymer type holographic recording medium; The photopolymer type holographic recording medium further includes a film-forming resin, a photosensitive initiation combination agent, a chain transfer agent, a catalyst and an additive, the film-forming resin includes a compound having multiple isocyanate reactive functional groups and a polyisocyanate-based compound.

11. The photopolymer-type holographic recording medium as described in claim 10, characterized in that, Each component includes the following weight parts: The first component: a compound having multiple isocyanate reactive functional groups 15-40 parts; The second component: a polyisocyanate-based compound 15-40 parts; The third component: an optical monomer 1-30 parts; The fourth component: a polymerizable monomer 10-40 parts; The fifth component: a photosensitive initiation combination agent 0.1-3 parts; The sixth component: a chain transfer agent 0.1-3 parts; The seventh component: a catalyst 0.1-5 parts; The eighth component: an additive 0.1-10 parts.

12. The photopolymer type holographic recording medium according to claim 10 or 11, wherein In the compound having multiple isocyanate reactive functional groups, the isocyanate reactive functional group is a hydroxyl group; The compound having multiple isocyanate reactive functional groups is selected from at least one of tetraethylene glycol, trimethylol ethane, glycerol, triethanolamine, polyester polyol with a molecular weight of 200-2000, polycarbonate polyol and polyether polyol; The polyisocyanate-based compound is a compound with two or more isocyanate groups; The polymerizable monomer is selected from at least one of alkenyl naphthalene compounds, alkenyl anthracene compounds, alkenyl benzene compounds, acrylic acid compounds, methacrylic acid compounds, acrylate compounds, methacrylate compounds, N-vinyl pyrrole, N-vinyl carbazole, N-vinyl imidazole, N-vinyl indole, N-vinyl pyrrolidone, trans-N-3-alkynyl butenyl carbazole; The photosensitive initiation combination agent includes a photosensitizer and a photoinitiator; the mass ratio of the photosensitizer and the photoinitiator is (0.001-1):(0.1-3); the absorption wavelength of the selected photosensitizer and the absorption wavelength of the photoinitiator in the photosensitive initiation combination agent are different; The chain transfer agent is a thiol compound; The catalyst is a tertiary amine catalyst or an organic metal catalyst; The additive includes one or more of defoaming agents, leveling agents, water removal agents and plasticizers.

13. A holographic optical element, characterized by The raw material of the holographic optical element includes the photopolymer type holographic recording medium of any one of claims 9-12.

14. An optical device, characterized by It includes the holographic optical element of claim 13.

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