(Methyl) acrylate monomer as well as preparation method and application thereof

Abstract

The invention relates to a (methyl) acrylate monomer as well as a preparation method and application thereof, the structural general formula of the (methyl) acrylate monomer is as follows: # imgabs0 #, n is an integer of 1-20, and R1 is methyl or hydrogen; r2 and R3 are selected from hydrogen, Br, phenyl, methyl or # imgabs 1 #, wherein A1 in the # imgabs 2 # is phenyl or methyl. According to the (methyl) acrylate monomer provided by the invention, the molecular size of the whole monomer is relatively small, the whole monomer has a plurality of branched chain structures, the carbon chain length of a main chain is controllable, and the (methyl) acrylate monomer has high refractive index and good intermiscibility with other components.

Description

Technical Field

[0001] The invention relates to the technical field of holographic materials, in particular to (meth)acrylate monomers and a preparation method and application thereof. Background Art

[0002] The various components used to make holographic recording media, such as photosensitive dyes, initiators, chain transfer agents, writing monomers, film-forming resins, plasticizers, etc., work together to determine whether the performance of the holographic recording media is good or not.

[0003] Among them, the migration rate and polymerization rate of the writing monomer jointly determine the speed of grating formation. The migration rate of the writing monomer is faster than the polymerization rate to obtain a grating with a 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 squeezes the film-forming resin in the bright area into the coherent dark area, so that the refractive index of the bright area is close to the refractive index of the writing monomer, and the refractive index of the dark area is close to 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. The greater the refractive index difference between the writing monomer and the film-forming resin, the faster the holographic recording medium can form a refractive index modulated volume holographic grating. In the existing refractive index modulated phase-type volume holographic grating prepared by photopolymer, the refractive index difference between the writing monomer and the film-forming resin is not significant enough, so that the refractive index modulated volume holographic grating cannot be quickly constructed, affecting the performance of the holographic recording medium. Summary of the invention

[0004] In view of this, the present invention proposes a (meth)acrylate monomer and a preparation method and application thereof, aiming to achieve a (meth)acrylate monomer with a higher refractive index so as to improve the holographic optical performance of a photopolymer holographic recording medium containing the (meth)acrylate monomer.

[0005] The (meth)acrylate monomer proposed in the first aspect of the present invention has a general structural formula as shown below:

[0006]

[0007] wherein n is an integer from 1 to 20, R1 is methyl or hydrogen; R2 and R3 are selected from hydrogen, Br, phenyl, methyl or in A1 in which is phenyl or methyl.

[0008] It can be seen from the above technical scheme that the (meth)acrylate monomer proposed in the first aspect of the present invention has a (meth)acrylate group, which has high refractive index and low volume shrinkage properties; and also contains multiple aromatic ring groups with high molar refractive index and low molar volume, as well as some sulfur atoms that have high refractive index themselves, so that the whole monomer molecule presents a higher refractive index as a whole. When the monomer has a halogen and aromatic ring structure, since the monomer also has an alkyl chain, the viscosity of the whole monomer is low; in this application, the length of the C chain in the main chain can be adjusted by adjusting the number of n, thereby adjusting the mechanical properties, viscosity and compatibility with other components of the whole molecule.

[0009] The second aspect of the present invention provides a method for preparing the (meth)acrylate monomer in each of the above examples, comprising the following steps: dissolving compound P1 and compound M1 in an organic solvent, adding a first photoinitiator, and reacting under light to obtain compound P2; completely mixing compound P2 and an acid binder in an organic solvent, and adding compound M2 until the reaction is complete, removing excess reactants and solvent, and separating to obtain the (meth)acrylate monomer;

[0010] The general structural formula of the compound P1 is: R2, R3 are selected from hydrogen, Br, phenyl, methyl or A1 is phenyl or methyl;

[0011] The structural formula of the compound M1 is Wherein n is an integer from 1 to 20;

[0012] The compound M2 is Wherein R1 is methyl or hydrogen.

[0013] The preparation method of (meth)acrylate monomers proposed in the second aspect of the present invention can synthesize the required (meth)acrylate monomers through two-step reactions. The reaction conditions are easy to control during the synthesis process. The first photoinitiator is used to quickly initiate the reaction between compound P1 and compound M1 and increase the reaction rate. In the reaction, the unsaturated bonds of compound M1 containing alkynes and hydroxyls are opened and connected to the S in the thiol group of compound P1 to form compound P2 with a saturated covalent bond SC bond. The hydroxyl group in compound P2 reacts with the halogen in compound M2 to finally generate a compound with a (meth)acrylate group, and the molecular structure of the entire compound is stable.

[0014] The photopolymer holographic recording medium containing (meth)acrylate monomers provided in the third aspect of the present invention comprises a writing monomer, wherein the writing monomer comprises the (meth)acrylate monomer and a polymerizable monomer.

[0015] The third aspect of the present invention proposes a photopolymer holographic recording medium containing (meth)acrylate monomers. By adding (meth)acrylate monomers and polymerizable monomers, the two components cooperate with each other to form a writing monomer component with a higher refractive index, so that the writing monomer and the film-forming resin can have a larger refractive index difference, providing the photopolymer holographic recording medium with the required material basis for forming a phase-type volume holographic grating with refractive index modulation.

[0016] A fourth aspect of the present invention provides a holographic optical element, wherein the material of the holographic optical element includes the photopolymer holographic recording medium of the aforementioned examples.

[0017] The holographic optical element proposed in the fourth aspect of the present invention has excellent holographic performance, high diffraction efficiency, high sensitivity, and small exposure amount required.

[0018] A fifth aspect of the present invention provides an optical device, comprising the holographic optical element as described above.

[0019] The optical device proposed in the fifth aspect of the present invention, such as a head-up display device, an augmented reality device, a virtual reality device, a photopolymer holographic storage optical disc, etc., has excellent holographic performance.

[0020] It should be understood that the above general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure of the embodiments of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained like these accompanying drawings without paying creative work.

[0022] Figure 1 is a graph showing holographic exposure characteristics of the photopolymer holographic recording media 2-1, 2-2, and 2-3 in Example 2;

[0023] Figure 2 It is a comparative holographic exposure characteristic curve. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0025] The photopolymer material used for holographic recording realizes holographic recording by polymerizing the writing monomers under light and then forming a phase-type holographic grating with refractive index modulation with the film-forming resin. The monomers in the coherent bright area are consumed and the concentration is reduced, while the monomers in the coherent dark area hardly react. The difference in monomer concentration between the bright and dark areas causes the monomers in the dark area to begin to migrate to the bright area, and the film-forming resin in the bright area is squeezed into the dark area. Finally, the refractive index of the bright area is close to that of the polymer, and the refractive index of the dark area is close to that of the film-forming resin, thereby forming a phase-type volume holographic grating with refractive index modulation.

[0026] The present invention provides a (meth)acrylate monomer as a component of the writing monomer, which is combined with an isocyanate-alcohol having a lower refractive index as a film-forming resin to form a refractive index-modulated volume holographic grating with a larger refractive index difference, thereby improving the holographic performance of the photopolymer holographic recording medium.

[0027] In the absence of conflict, the following embodiments and features of the embodiments may be combined with each other.

[0028] The (meth)acrylate monomer of the present invention is described below.

[0029] A (meth)acrylate monomer proposed in the present invention has a general structural formula as shown below:

[0030]

[0031] wherein n is an integer of 1 to 20, R1 is methyl or hydrogen; R2 and R3 are selected from hydrogen, Br, phenyl, methyl or in A1 in which is phenyl or methyl.

[0032] As can be seen from the above, the (meth)acrylate monomer proposed in the present invention has a (meth)acrylate group, has high refractive index and low volume shrinkage properties; and also contains multiple aromatic ring groups with high molar refractive index and low molar volume, as well as some sulfur atoms that have high refractive index themselves, so that the whole monomer molecule presents a higher refractive index as a whole. When the monomer has a halogen and aromatic ring structure, since the monomer also has an alkyl chain, the viscosity of the whole monomer is low; in this application, the length of the C chain in the main chain can be adjusted by adjusting the number of n, thereby adjusting the mechanical properties, viscosity and compatibility with other components of the whole molecule. It has good compatibility with other components, and the acrylate group can quickly connect the surrounding small molecules. When used in photopolymer holographic recording media, it can improve the holographic performance.

[0033] In some examples, the (meth)acrylate monomer is selected from monomers having the following structural formula:

[0034]

[0035] Wherein R1 is methyl or hydrogen, and n is an integer from 1 to 10.

[0036] Then, the (meth)acrylate monomers of each structure in the above examples all have the advantages of high refractive index, small molecular structure, multiple short branches, good compatibility with other components, and easy migration. The structures of the (meth)acrylate monomers in the above examples are only exemplary and not exhaustive. Any compound belonging to the aforementioned general formula G of the present invention should be within the protection scope of the present invention.

[0037] In some examples, the refractive index of the (meth)acrylate monomer is 1.60 to 1.65, and the kinematic viscosity is 20 to 100 mm 2 / s.

[0038] The following is a description of the preparation method of the (meth)acrylate monomer of the present invention.

[0039] The method for preparing the (meth)acrylate monomer in each of the above examples according to the present invention comprises the following steps:

[0040] Step S1, dissolving compound P1 and compound M1 in an organic solvent, adding a first photoinitiator, and reacting under light to obtain compound P2.

[0041] The general structural formula of compound P1 in step S1 is: R2, R3 are selected from hydrogen, Br, phenyl, methyl or A1 is phenyl or methyl;

[0042] The structural formula of compound M1 is Wherein n is an integer from 1 to 20.

[0043] In some specific examples, compound P1 is selected from compounds having the following structural formulas, which are only examples and not exhaustive. All compounds conforming to the general structural formula of compound P1 should be included in the protection scope of the present invention:

[0044]

[0045] It can be understood that in step S1, the first photoinitiator is rapidly activated under the action of light, so that compound P1 and compound M1 can reach the desired reaction conditions, the alkyne in compound M1 is ring-opened, and combined with the thiol -S- in compound P1, and the general structural formula of compound P2 generated by the reaction in step S1 is as follows:

[0046] Wherein n is an integer of 1 to 20, R2 and R3 are selected from hydrogen, Br, phenyl, methyl or A1 in which is phenyl or methyl.

[0047] In some examples, the first photoinitiator includes at least one of (2,4,6-trimethylbenzoyl chloride) diphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphosphonate, 2-methyl-1-[4-methylthiophenyl]-2-morpholinyl-1-propanone, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin dimethyl ether, methyl o-benzoylbenzoate, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone, bis-2,6-difluoro-3-pyrrolphenyl titanocene, and ethyl 4-dimethylamino-benzoate.

[0048] Among these examples of the first photoinitiator, (2,4,6-trimethylbenzoyl chloride) diphenylphosphine oxide (also known as photoinitiator TPO) has an absorption wavelength of 350nm to 400nm. After exposure to light, it can generate two free radicals, benzoyl and phosphoryl, which can both initiate polymerization. It has a fast photocuring speed, low volatility, no yellowing of the coating, low polymerization effect, and no residue, and can be used for transparent layer structures.

[0049] Ethyl 2,4,6-trimethylbenzoylphosphonate (also known as photoinitiator TPO-L) has an absorption wavelength of 270nm to 370nm.

[0050] The absorption wavelength of 2-methyl-1-[4-methylthiophenyl]-2-morpholinyl-1-propanone (also known as photoinitiator 907) is 231nm to 307nm, and it has extremely high absorption.

[0051] The absorption wavelength of 1-hydroxy-cyclohexyl-phenyl ketone (also known as photoinitiator 184) is 246nm and 278nm. It has good yellowing resistance.

[0052] The absorption wavelength of 2-hydroxy-2-methyl-1-phenyl-1-propanone (also known as photoinitiator 1173) is 244nm. It is a liquid product, easy to blend and easy to use with other photoinitiators. It is highly efficient, low in yellowing, and has certain volatility at high temperatures.

[0053] The absorption wavelength of benzoin dimethyl ether (also known as photoinitiator BDK) is 205nm~253nm. It is a highly efficient and stable photoinitiator, which has stronger absorption performance than 1173 and 184, thus it can more effectively promote the cross-linking reaction of double bonds.

[0054] The absorption wavelength of methyl o-benzoylbenzoate (also known as photoinitiator OMBB) is 253nm.

[0055] The absorption wavelength of bis-2,6-difluoro-3-pyrrolphenyl titanocene (also known as photoinitiator FMT) is between 333nm and 470nm.

[0056] Phenylbis(2,4,6-trimethylbenzoyl)phosphine oxide (also known as photoinitiator 819) has excellent ultraviolet absorption characteristics, with absorption wavelengths at 295nm and 370nm. It can absorb long-wave ultraviolet light near the above wavelengths, and can provide excellent curing effect and anti-yellowing performance at a very low addition amount.

[0057] 2-Hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone (also known as photoinitiator 127) has an absorption wavelength of 259 nm, is less sensitive to oxygen, has good surface curing effect, low volatility, and has low odor itself and the odor of photolysis products.

[0058] The absorption wavelength of 4-dimethylamino-ethyl benzoate (also known as photoinitiator EDB) is 228nm~308nm.

[0059] The first photoinitiator mentioned above may be used alone or in combination of multiple types.

[0060] In some examples, compound P1, compound M1 and the first photoinitiator are fed and dissolved in an organic solvent at a molar ratio of 1: (0.2-0.5): (0.01-0.03). Within the above ratio range, the reaction process is reasonable, and the reaction of compound P1 and compound M1 is relatively complete with less residue. For example, the molar ratio of compound P1, compound M1 and the first photoinitiator is 1: 0.2: 0.01, 1: 0.3: 0.02, 1: 0.4: 0.03, 1: 0.5: 0.03, etc.

[0061] In some examples, the light intensity is 5-300 mW / cm 2 , the wavelength of the light is 200-405nm, the reaction time under light is 1h-3h, and the first photoinitiator is an ultraviolet light initiator. By selecting a first photoinitiator that matches the wavelength of the light, the reaction in step S1 can be induced quickly under light; controlling the light exposure time to 1h-3h can achieve complete reaction while ensuring that the time of the entire reaction process is controlled within a reasonable range. For example, the light intensity is 5mW / cm 2 、10mW / cm 2 、15mW / cm 2 , 20mW / cm 2 , 25mW / cm 2 、30mW / cm 2 、35mW / cm 2 , 45mW / cm 2 、55mW / cm2 、65mW / cm 2 、75mW / cm 2 、85mW / cm 2 、95mW / cm 2 , 100mW / cm 2 , 200mW / cm 2 、300mW / cm 2 For example, the wavelength of the light is 200nm, 215nm, 253nm, 278nm, 308nm, 345nm, 365nm, 400nm, 405nm, etc. For example, the light exposure time is 1h, 2h, 3h, etc. More specifically, the light exposure time is 1.5h to 2.5h, for example, 1.5h, 2.0h and 2.5h.

[0062] In some examples, the solvent selected in step S1 includes one or more of ethanol, petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, acetonitrile, N,N-dimethylformamide or dimethyl sulfoxide. More specifically, tetrahydrofuran, ethyl acetate, N,N-dimethylformamide, and dimethyl sulfoxide are selected. These solvents have good compatibility with compound P1, compound M1, and the first photoinitiator; it is also convenient to control the concentration of the two compounds to make the reaction system more uniform; after the reaction is completed, these solvents have good volatility, so it is convenient to remove the above solvents to obtain the desired reacted substances, which is convenient for further processing.

[0063] Step S2, completely mixing compound P2 and an acid-binding agent in an organic solvent, and adding compound M2 until the reaction is complete, removing excess reactants and solvent, and separating to obtain a (meth)acrylate monomer;

[0064] The compound M2 used in step S2 is Wherein R1 is methyl or hydrogen, when R1 is methyl, it is methacryloyl chloride, and when R1 is hydrogen, it is acryloyl chloride.

[0065] In some examples, the molar ratio of compound P2, acid binding agent and compound M2 is 1: (1-2): (1-2). By using an acid binding agent, the protons in the reaction system can be effectively neutralized, the effect of the acid on the reaction can be reduced, and the hydrogen ions in the solution can be fixed to protect other substances from the acidic environment, which is conducive to further reaction between compound P2 and compound M2. For example, in a specific example, the molar ratio of compound P2, acid binding agent and compound M2 is 1: 1: 1, 1: 2: 1, 1: 1.5: 1, 1: 1.5: 1.5, 1: 2: 2. In a more specific example, the molar ratio of compound P2, compound M2 and acid binding agent can be selected between 1: (1-1.5): (1-1.5).

[0066] In a specific example, the acid-binding agent includes at least one of triethylamine, pyridine, N,N-diisopropylethylamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, potassium carbonate, ammonium carbonate and sodium carbonate. The raw materials are easily available and can be easily separated from the (meth)acrylate monomers finally obtained.

[0067] In some examples, the reaction temperature of compound P2, acid-binding agent and compound M2 is controlled at 0°C, for example, by using an ice bath, which helps control the reaction rate and prevents overheating from causing an increase in side reaction products or decomposition of the target substance, thereby helping to improve the yield and selectivity of the main reaction, reduce the volatilization of volatile substances and the degradation of unstable substances. It is also helpful for the subsequent separation and purification of the target product.

[0068] In some examples, removing excess compound M2 from the reactants is achieved by adding dilute hydrochloric acid.

[0069] In some examples, the mixed solution after the reaction in step S2 is washed with saturated NaCl solution, saturated NaHCO3 solution and deionized water in sequence, the organic phase is dried over anhydrous sodium sulfate, excess solvent is removed by rotary evaporation, and then separated by column chromatography to obtain the (meth)acrylate monomer of the present invention.

[0070] In some examples, the solvent includes one or more of ethanol, petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, acetonitrile, N,N-dimethylformamide or dimethyl sulfoxide, as long as it can facilitate the reaction of compound P2 and compound M2, and has good compatibility with compound P2, acid binding agent and compound M2. For example, in step S2, more specifically, the following solvents can be selected: dichloromethane, chloroform, ethyl acetate.

[0071] As can be seen from the above, the preparation method of the (meth)acrylate monomer proposed in the present invention can synthesize the required (meth)acrylate monomer through two-step reaction. The reaction conditions are easy to control during the synthesis process. The first photoinitiator is used to quickly initiate the reaction between the compound P1 and the compound M1 and improve the reaction rate. In the reaction, the unsaturated bond of the compound M1 containing alkynes and hydroxyl groups is opened and connected to the S in the thiol group of the compound P1 to form a saturated covalent bond. The hydroxyl group in the compound P2 reacts with the halogen in the compound M2 to finally generate a compound with a (meth)acrylate group, and the molecular structure of the entire compound is stable.

[0072] Then, the preparation method of the (meth)acrylate monomer having the general structural formula G comprises the following two steps of reaction:

[0073] The first step is to open the carbon-carbon triple bond in compound M1 and combine with two equivalents of thiol to form a -SC- saturated bond, as shown below:

[0074]

[0075] The second step is that the carbonyl group of methacryloyl chloride / acryloyl chloride reacts with the hydroxyl group in compound P2 to generate a compound monomer with methacrylate / acrylate in G, as shown below:

[0076]

[0077] In some examples, compound P1 is selected from compounds having the following structural formula:

[0078]

[0079] That is to say, after the compound P1 of these structural formulas is synthesized with the compound M1, the (meth)acrylate monomers of the structural formulas listed above can be synthesized accordingly. In compound M1, the carbon-carbon triple bond opens, and the H of -SH in compound P1 transfers, thereby forming a polymerization of two monomers.

[0080] The photopolymer type holographic recording medium containing a (meth)acrylate monomer of the present invention is described below.

[0081] The photopolymer holographic recording medium according to the present invention, which contains the (meth)acrylate monomers in the above examples, comprises a writing monomer, wherein the writing monomer comprises a (meth)acrylate monomer and a polymerizable monomer.

[0082] The photopolymer holographic recording medium containing (meth)acrylate monomers proposed in the present invention can form a writing monomer component with a higher refractive index by adding (meth)acrylate monomers and polymerizable monomers. The two components cooperate with each other, so that the writing monomer and the film-forming resin can have a larger refractive index difference, providing the photopolymer holographic recording medium with the required material basis for forming a phase-type volume holographic grating with refractive index modulation.

[0083] In some examples of the present invention, the weight percentage of the writing monomer in the entire photopolymer holographic recording medium is 30% to 60%. This allows the writing monomer to have a sufficient concentration to achieve a concentration difference between bright and dark areas after reaction under light. The photopolymer holographic recording medium also includes a film-forming resin, a photosensitive initiator composition, 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 compound. When the film-forming resin and the writing monomer are combined, a refractive index modulated volume holographic grating with a refractive index difference can be formed.

[0084] In some embodiments of the invention, the photopolymer holographic recording medium containing (meth)acrylate monomers comprises the following components in parts by weight:

[0085] First component: 20 to 50 parts of a compound having multiple isocyanate-reactive functional groups, for example, 20 parts, 30 parts, 40 parts, 50 parts, etc.

[0086] Second component: 10 to 40 parts of polyisocyanate compound, for example, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc.

[0087] The third component: 3 to 30 parts of (meth)acrylate monomers, for example, 3 parts, 4 parts, 5 parts, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, etc.

[0088] The fourth component: 0.1 to 47 parts of polymerizable monomers, for example, 0.1, 0.3, 1, 2, 5, 10, 15, 20, 25, 30, 40, 47, etc.

[0089] The fifth component: 0.1 to 4 parts of the photosensitive initiator composition, for example, 0.1, 0.2, 0.3, 0.5, 1, 1.5, 2.0, 2.5, 3.0, 3.5, 4, etc.

[0090] Sixth component: 0.1 to 3 parts of chain transfer agent, for example, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.5, 2.0, 2.2, 2.5, 2.8, 3, etc.

[0091] Seventh component: 0.1 to 3 parts of catalyst, for example, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1.0, 1.5, 2.0, 2.2, 2.5, 2.8, 3, etc.

[0092] The eighth component: 0.1 to 7 parts of additives, for example, 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, etc.

[0093] As can be seen from the above, the photopolymer holographic recording medium containing (meth)acrylate monomers proposed in the present invention can achieve full synergistic effect of each component by reasonably controlling the addition amount of each component, and the holographic performance of the final photopolymer holographic recording medium will not be deteriorated due to excessive or insufficient amount of a certain component, thereby ensuring that the comprehensive holographic performance of the final photopolymer holographic recording medium is better.

[0094] For example, by controlling the compound with multiple isocyanate reactive functional groups to 20 to 50 parts and the polyisocyanate-based compound to 10 to 40 parts, the first component and the second component together form a film-forming resin with a lower refractive index, thereby providing support for the other components. In some specific examples, the compound with multiple isocyanate reactive functional groups is further controlled to 25 to 35 parts, and the polyisocyanate-based compound is further controlled to 15 to 25 parts.

[0095] By controlling the (meth)acrylate monomers to 3 to 30 parts, and the polymerizable monomers to 0.1 to 47 parts, the third component and the fourth component are a writing monomer system, and the intermolecular bonding refractive index will be higher after polymerization, then the interaction of the above four components can realize a photopolymer holographic recording medium having a high refractive index component and a low refractive index component with a large refractive index difference, and form a high refractive index difference between the film-forming resin and the writing monomer. Therefore, under the action of light, the monomers in the bright area (such as the third component and the fourth component) are polymerized and consumed and the concentration is reduced, and the monomers in the dark area hardly react. The difference in monomer concentration between the bright and dark areas causes the high-concentration monomers in the dark area to begin to migrate to the bright area, and the components of the film-forming resin in the bright area (such as the first component and the second component) are squeezed into the dark area, so that the refractive index of the bright area is close to the refractive index of the third component and the fourth component, and the refractive index of the dark area is close to 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 (meth)acrylate monomer is further controlled to be 3 to 15 parts; and the polymerizable monomer is further controlled to be 25 to 40 parts.

[0096] For example, controlling the photosensitive initiator composition to 0.1 to 4 parts can absorb a suitable number of photons during exposure, control the polymerization reaction at a certain speed, enable the grating to be formed quickly, and obtain a higher diffraction efficiency; in addition, it can also ensure that the final holographic recording medium has the required light transmittance and that the grating has a certain diffraction efficiency. In some specific examples, the photosensitive initiator composition is 0.3 to 3 parts.

[0097] For example, controlling the chain transfer agent to 0.1 to 3 parts can keep the polymer chain length within a reasonable range and effectively prevent excessive polymerization, ensuring that the final holographic recording medium has the required optical properties and diffraction efficiency. In some specific examples, the chain transfer agent is further controlled to 0.5 to 2 parts.

[0098] For example, controlling the catalyst to 0.1 to 3 parts can effectively increase the reaction rate of the relevant components and the consumption rate of the relevant components after exposure, thereby quickly forming a concentration difference between the monomers in the bright and dark areas and realizing a phase-type volume holographic grating with refractive index modulation. In some specific examples, the catalyst is further controlled to 0.5 to 2 parts.

[0099] For example, controlling the additive to 0.1 to 7 parts, taking the additive as a leveling agent as an example, can effectively improve the uniformity of the mixed liquid, improve fluidity, and reasonably control costs. In some specific examples, the additive is further controlled to 0.6 to 6 parts.

[0100] In some optional examples, the photopolymer holographic recording medium containing (meth)acrylate monomers includes the following components in parts by weight: a first component - 25 parts of a compound having multiple isocyanate-reactive functional groups, a second component - 21 parts of a polyisocyanate compound, a third component - 31 parts of a (meth)acrylate monomer, a fourth component - 19 parts of a polymerizable monomer, a fifth component - 2 parts of a photosensitive initiator combination agent, a sixth component - 2 parts of a chain transfer agent, a seventh component - 0.7 parts of a catalyst, and an eighth component - 1.3 parts of an additive.

[0101] In some optional examples, the photopolymer holographic recording medium containing (meth)acrylate monomers includes the following components in parts by weight: a first component - 20 parts of a compound having multiple isocyanate-reactive functional groups, a second component - 37 parts of a polyisocyanate compound, a third component - 3 parts of a (meth)acrylate monomer, a fourth component - 23 parts of a polymerizable monomer, a fifth component - 4 parts of a photosensitive initiator combination agent, a sixth component - 3 parts of a chain transfer agent, a seventh component - 3 parts of a catalyst, and an eighth component - 7 parts of an additive.

[0102] In some optional examples, the photopolymer holographic recording medium containing (meth)acrylate monomers includes the following components in parts by weight: a first component - 51 parts of a compound having multiple isocyanate-reactive functional groups, a second component - 10 parts of a polyisocyanate compound, a third component - 12 parts of a (meth)acrylate monomer, a fourth component - 18 parts of a polymerizable monomer, a fifth component - 1 part of a photosensitive initiator combination agent, a sixth component - 1 part of a chain transfer agent, a seventh component - 2 parts of a catalyst, and an eighth component - 5 parts of an additive.

[0103] In some optional examples, the photopolymer holographic recording medium containing (meth)acrylate monomers includes the following components in parts by weight: a first component - 32 parts of a compound having multiple isocyanate-reactive functional groups, a second component - 10 parts of a polyisocyanate compound, a third component - 3 parts of a (meth)acrylate monomer, a fourth component - 48 parts of a polymerizable monomer, a fifth component - 4 parts of a photosensitive initiator combination agent, a sixth component - 1 part of a chain transfer agent, a seventh component - 1 part of a catalyst, and an eighth component - 1 part of an additive.

[0104] In some optional examples, the photopolymer holographic recording medium containing (meth)acrylate monomers includes the following components in parts by weight: a first component - 38 parts of a compound having multiple isocyanate-reactive functional groups, a second component - 10 parts of a polyisocyanate compound, a third component - 30 parts of a (meth)acrylate monomer, a fourth component - 10.6 parts of a polymerizable monomer, a fifth component - 4 parts of a photosensitive initiator combination agent, a sixth component - 0.1 parts of a chain transfer agent, a seventh component - 0.3 parts of a catalyst, and an eighth component - 7 parts of an additive.

[0105] In some optional examples, the photopolymer holographic recording medium containing (meth)acrylate monomers includes the following components in parts by weight: a first component - 33 parts of a compound having multiple isocyanate-reactive functional groups, a second component - 16 parts of a polyisocyanate compound, a third component - 31 parts of a (meth)acrylate monomer, a fourth component - 10 parts of a polymerizable monomer, a fifth component - 4 parts of a photosensitive initiator combination agent, a sixth component - 3 parts of a chain transfer agent, a seventh component - 0.5 parts of a catalyst, and an eighth component - 2.5 parts of an additive.

[0106] In some optional examples, the photopolymer holographic recording medium containing (meth)acrylate monomers includes the following components in parts by weight: a first component - 25 parts of a compound having multiple isocyanate-reactive functional groups, a second component - 35 parts of a polyisocyanate compound, a third component - 22 parts of a (meth)acrylate monomer, a fourth component - 8 parts of a polymerizable monomer, a fifth component - 0.2 parts of a photosensitive initiator combination agent, a sixth component - 0.8 parts of a chain transfer agent, a seventh component - 2 parts of a catalyst, and an eighth component - 7 parts of an additive.

[0107] In some optional examples, the photopolymer holographic recording medium containing (meth)acrylate monomers includes the following components in parts by weight: a first component - 35 parts of a compound having multiple isocyanate-reactive functional groups, a second component - 15 parts of a polyisocyanate compound, a third component - 21 parts of a (meth)acrylate monomer, a fourth component - 28.6 parts of a polymerizable monomer, a fifth component - 0.1 parts of a photosensitive initiator combination agent, a sixth component - 0.1 parts of a chain transfer agent, a seventh component - 0.1 parts of a catalyst, and an eighth component - 0.1 parts of an additive.

[0108] In some examples of the present invention, in the compound having multiple isocyanate reactive functional groups, the isocyanate reactive functional groups are hydroxyl and thiol. Hydroxyl is a polar group, in which alcoholic hydroxyl is easily oxidized and has high reactivity; thiol also has high reactivity. For example, in a specific example, the compound having multiple isocyanate reactive functional groups is a compound with a low refractive index and two or more hydroxyl and thiol functional groups.

[0109] More specifically, the compound having multiple isocyanate-reactive functional groups is selected from 2-ethyl-1,3-hexanediol, 1,2,4-butanetriol, 1,6-hexanediol, 2,5-hexanediol, 1,4-cyclohexanediol, 1,8-octanediol, 1,7-heptanediol, 1,3-butanediol, 1,5-pentanediol, 1,4-cyclohexanedimethanol, 1,3-cyclopentanediol, tetraethylene glycol, trimethylolethane, trimethylol At least one of propane, glycerol, triethanolamine, polyester polyol with a molecular weight of 100 to 2000, polycarbonate polyol, polyether polyol, 2,3-dithio(2-mercapto)-1-propanethiol, 1,2-octanedithiol, 2,5-dimethylmercapto-1,4-dithiane, 1,2-butanethiol, 1,3-butanethiol, 3,7-dithia-1,9-nonanethiol, and 2,3-butanethiol. The refractive index of these substances is also low, for example: the refractive index of 2-ethyl-1,3-hexanediol is 1.451; the refractive index of 1,6-hexanediol is 1.457; the refractive index of 2,5-hexanediol is 1.443; the refractive index of 1,4-cyclohexanediol is 1.427; the refractive index of tetraethylene glycol is 1.46 (20°C); the refractive index of 1,2,4-butanetriol is 1.47; 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).

[0110] In some examples of the present invention, the polyisocyanate-based compound is a compound having a low refractive index and having two or more isocyanate groups.

[0111] In a specific example, the polyisocyanate compound is selected from at least one of hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl)tris(hexamethylene)isocyanate, butane-1,4-diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate. 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 1.473; the refractive index of butane-1,4-diisocyanate is 1.453; the refractive index of isophorone diisocyanate is 1.484; and the refractive index of dicyclohexylmethane diisocyanate is 1.496 (25°C).

[0112] In some examples of the present invention, the polymerizable monomer is selected from at least one of alkenyl naphthalene compounds, alkenyl anthracene compounds, alkenyl benzene compounds, acrylic compounds, methacrylic compounds, acrylate compounds, methacrylate compounds, N-vinyl pyrrole, N-vinyl carbazole, N-vinylimidazole, N-vinyl indole, N-vinyl pyrrolidone, and trans-N-3-ynyl butenyl carbazole.

[0113] In a specific example, the alkenyl naphthalene compound is selected from at least one of 1-vinyl naphthalene and 2-vinyl naphthalene.

[0114] In a specific example, the alkenyl anthracene compound is selected from at least one of 2-vinyl anthracene and 9-vinyl anthracene.

[0115] In a specific example, the alkenylbenzene compound is selected from at least one of styrene, 2-chlorostyrene, 2-bromostyrene, 3-chlorostyrene, 3-bromostyrene, 4-chlorostyrene, 4-bromostyrene, p-(chloromethyl)styrene, and p-(bromomethyl)styrene.

[0116] In a specific example, the methacrylic compound includes at least one of methacrylic acid and derivatives thereof.

[0117] In a specific example, the acrylate compound is selected from at least one of pentabromophenyl acrylate, pentachlorophenyl acrylate, phenoxyethyl acrylate, pentabromobenzyl acrylate, 2-naphthyl acrylate, 1,4-di(2-thionaphthyl)2-butyl acrylate, phenoxyethoxyethyl acrylate, bisphenol A diacrylate, tetrabromobisphenol A diacrylate, 2-phenoxyethyl acrylate, benzyl acrylate, p-chlorophenyl acrylate, 2,4,6-trichlorophenyl acrylate, p-bromophenyl acrylate, 2,4,6-tribromophenyl acrylate, propane-2,2-diylbis[(2,6-dibromo-4,1-phenylene)oxy(2-{[3,3,3-tri(4-chlorophenyl)propionyl]oxy}propane-3,1-diyl)oxyethane-2,1-diyl]diacrylate.

[0118] In a specific example, 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-di(2-thionaphthyl) 2-butyl methacrylate, pentabromobenzyl methacrylate, 2-naphthyl methacrylate, bisphenol A dimethacrylate, and tetrabromobisphenol A dimethacrylate.

[0119] In some examples of the present invention, the photosensitive initiator combination includes a photosensitizer and a second photoinitiator. The photosensitizer can be matched with the second photoinitiator to realize a visible light initiation system and adapt to lasers of different wavelengths. Under the irradiation of light in a specific wavelength range, the photosensitizer in the photoinitiator system is activated by the corresponding light, absorbs light energy, and transfers the light energy to the second photoinitiator, so that the second photoinitiator can be activated under light radiation in a wider wavelength range to generate free radicals with initiation function. The photoinitiator free radicals can initiate monomer polymerization to realize the construction of holographic gratings, improve the photosensitivity of photopolymer holographic recording media, and broaden the range of optional radiation sources for light radiation.

[0120] It can be understood that, in other examples, when the present invention uses a second photoinitiator with an adapted wavelength, no photosensitizer may be added.

[0121] When the photosensitive initiator combination contains both a photosensitizer and a second photoinitiator, further, the mass ratio of the photosensitizer to the second photoinitiator is (0.001-1):(0.1-3). By controlling the mass ratio of the photosensitizer to the second photoinitiator within the above range, the concentration of the photosensitizer can be effectively controlled, so that during the holographic exposure process, the number of absorbed photons is controlled within a suitable range, the speed of the polymerization reaction is controlled within a reasonable range, and the speed of grating formation is controlled within a certain range, thereby ensuring the light transmittance of the photopolymer holographic recording medium and obtaining excellent diffraction efficiency. In a more specific example, the mass of the photosensitizer is 1 / 10 to 1 / 3 of the mass of the second photoinitiator, such as 1 / 10, 1 / 9, 1 / 8, 1 / 7, 1 / 6, 1 / 5, 1 / 4 or 1 / 3, etc.

[0122] In the present invention, different broadband responses can be achieved by regulating the type of photosensitizer. For example, the photosensitizer is a dye with high electron transfer efficiency under light.

[0123] In a specific example, the photosensitizer is selected from at least one of cyanine dyes, fluorescein dyes, coumarin ketone dyes, nitrogen-containing aromatic heterocyclic compounds, aromatic amine compounds, and benzylcycloalkane ketone compounds.

[0124] More specifically, the photosensitizer is selected from new methylene blue (maximum absorption wavelength 666nm), thionine (absorption wavelength 602.5nm), basic yellow (absorption wavelength 412nm), pinacol cyanol chloride, rhodamine 6G (absorption wavelength 400nm-700nm), gallocyanine, ethyl violet (absorption wavelength 596nm), Victoria blue R (maximum absorption wavelength 615nm), lapis lazuli blue (absorption wavelength 630-640nm), methylene blue (maximum absorption wavelength 662nm), basic orange, daro red (maximum absorption wavelength 502nm) , pyrrole red Y (strong absorption wavelengths are 235nm, 267nm, 336nm, 515nm), basic red 29, quinaldine red (maximum absorption wavelength 528nm), crystal violet (absorption wavelength 588nm ~ 592nm), ethyl violet (maximum absorption wavelength 596nm), brilliant green (maximum absorption wavelength 630nm), azure A (maximum absorption wavelength 633nm), crystal violet white nitrile (maximum absorption wavelength 579nm), malachite green white nitrile, eosin (absorption wavelength 510nm ~ 518nm) one or more.

[0125] In a specific example, the second photoinitiator is selected from at least one of aromatic ketone compounds, benzoin and its derivatives, benzyl ketal, acylphosphine oxide, aryl ammonium borate, chromium salt, aryl diazonium salt, onium salt, and organic metal compound. It can also be other second photoinitiators with similar functions, which are not limited in the present invention.

[0126] More specifically, the second photoinitiator is selected from benzophenone (absorption wavelength 210nm, 255nm), alkyl benzophenone (290nm ~ 360nm), 4,4'-bis (dimethylamino) benzophenone, anthrone (299nm ~ 366nm) and halogenated benzophenone, 2,4,6-trimethylbenzoyl diphenylphosphine oxide (absorption wavelength of 350nm ~ 400nm), bisacylphosphine oxide, phenyl dihydroxyacetate, camphorquinone (absorption wavelength of 40 0nm~500nm), a-aminoalkylphenone (absorption wavelength is 380nm~430nm), α,α-dialkoxyacetophenone, a-hydroxyalkylphenone (absorption wavelength is 320nm~380nm), triphenylhexyl borate tetrabutylammonium, tri-(3-fluorophenyl)hexyl borate tetrabutylammonium, tri-(3-chloro-4-methylphenyl)hexyl borate tetrabutylammonium, ferrocenyl compounds, iodonium salts, sulfonium salts, hexaarylbisimidazoles, etc. One or more of the above. When these second photoinitiators are irradiated with light in the corresponding wavelength range, they can be quickly activated and generate active free radicals, thereby initiating polymerization reactions between the components of the photopolymer type holographic recording medium to achieve a difference in monomer concentration between the bright area and the dark area. Alternatively, when the photosensitizer coordinated therewith absorbs light in the corresponding wavelength range, it transfers heat to the second photoinitiator, thereby achieving activation of the photoinitiator.

[0127] In some examples of the present invention, the chain transfer agent is a thiol compound.

[0128] In a specific example, the chain transfer agent includes one or more of dodecyl mercaptan, mercaptoethanol, hexanethiol, phenylethyl mercaptan, 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol, 4-methyl-4H-1,2,4-triazole-3-thiol, and the like.

[0129] In some examples of the present invention, the catalyst is a tertiary amine catalyst or an organic metal catalyst.

[0130] In a specific example, 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 catalyze the polymerization reaction of the aforementioned related components under light, and those skilled in the art should understand that these all fall within the scope of protection of the present invention.

[0131] In some examples of the present invention, the additive includes one or more of a defoamer, a leveling agent, a plasticizer, and a water scavenger.

[0132] In a specific example, the defoamer is an organosilicon defoamer and / or a polymer defoamer without organosilicon, and the weight of the defoamer in the photopolymer holographic recording medium is less than or equal to 3%. The defoamer can reduce the surface tension of the liquid and remove bubbles, thereby improving the fluidity of the mixture of the components.

[0133] 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 mixture of these defoamers in any proportion. BYK series defoamers have excellent defoaming performance, good compatibility with other components, and good dispersibility; among them, BYK-011, BYK-012, BYK-014 and BYK-051N are polymer defoamers that do not contain silicone. DC65 is a water-based ink that dries quickly, has good printing effects, and is not easy to fall off. AFE-7820 has high efficiency in defoaming performance.

[0134] In a specific example, the leveling agent is an organic silicon surface additive, and the weight of the leveling agent in the photopolymer holographic recording medium is less than or equal to 3%. 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 mixture of these surface additives. BYK series leveling agents have excellent leveling properties.

[0135] In a specific example, the plasticizer is selected from at least one of toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, and phthalate, and the weight percentage of the plasticizer in the photopolymer holographic recording medium is less than or equal to 3%. The plasticizer is inserted between polymer molecular chains to weaken the stress between molecules, increase the mobility of molecular chains, and reduce crystallinity, thereby increasing the plasticity of the polymer.

[0136] In a specific example, the dehydrating agent is selected from toluenesulfonyl isocyanate, triethyl orthoformate, CUWR-WB20 dehydrating agent of Guangzhou Yourun Synthetic Materials Co., Ltd., ALT-201 dehydrating agent of Anxiang Elite Chemical Co., Ltd., PCCI dehydrating agent of Shanghai Ruhr Chemical Trading Co., Ltd., etc.

[0137] In some examples, the weight percentage of the dehydrating agent in the photopolymer holographic recording medium is less than or equal to 3%. The dehydrating agent can remove excess water during the reaction, so that the components can be mixed better without stratification.

[0138] Next, the application of the aforementioned photopolymer type holographic recording medium of the present invention will be described.

[0139] The holographic optical element proposed by the present invention is made of materials including the photopolymer holographic recording media in the above-mentioned examples. The holographic optical element includes but is not limited to a volume holographic grating.

[0140] It can be seen from the above that the holographic optical element proposed in the present invention, because it includes the photopolymer holographic recording medium of the present invention, also has the advantages of the photopolymer holographic recording medium of the present invention, such as high diffraction efficiency, high sensitivity and small exposure required.

[0141] The optical device proposed by the present invention includes the holographic optical element as described above. The optical device includes but is not limited to a head-up display device (HUD), an augmented reality device (AR device, Augmented Reality), a virtual reality device (VR device, Virtual Reality), a photopolymer holographic storage disc, etc. The photopolymer holographic storage disc can be erasable and rewritable and record in real time, is suitable for storing a large amount of data, and has a very fast data transmission speed.

[0142] It can be seen from the above that the optical device proposed by the present invention, because it includes the holographic optical element mentioned above, also has the advantages of the holographic optical element of the present invention. The optical device has excellent holographic performance, clear images, and can store a large amount of data.

[0143] The (meth)acrylate monomer, the preparation method of the (meth)acrylate monomer, and the photopolymer holographic recording medium containing the (meth)acrylate monomer of the present invention are described below with reference to specific embodiments.

[0144] Example 1

[0145] The general structural formula of the (meth)acrylate monomer in this embodiment is G:

[0146] The preparation method of the (meth)acrylate monomer of structural formula G comprises the following steps:

[0147] Step S1: Compound P1 and compound M1 were dissolved in an organic solvent ethyl acetate at a molar ratio of 1:0.5 (i.e., 2:1), and a first photoinitiator 2,4,6-trimethylbenzoylphosphonic acid ethyl ester was added, and the mixture was heated to 30 mW / cm 2 The wavelength of the light is 365 nm, and the reaction is carried out under light for 1.5 hours to obtain compound P2. The reaction equation is as follows:

[0148]

[0149] Step S2: Compound P2 and acid-binding agent triethylamine are completely mixed in an organic solvent ethyl acetate, and compound M2 methacryloyl chloride / acryloyl chloride is added to complete the reaction, dilute hydrochloric acid is added to remove excess compound M2, saturated NaCl solution, saturated NaHCO3 solution and deionized water are used to wash in sequence, the organic phase is dried over anhydrous sodium sulfate, excess solvent is removed by rotary evaporation, and then separated by column chromatography to obtain the (meth) acrylate monomer G1 of the present invention. The reaction equation is as follows:

[0150]

[0151] Then, the reaction conditions are roughly the same, M1 remains unchanged (for example, n is 1), and by replacing P1 with different R2 and R3 groups in step S1, and / or replacing M2 with different R1 in step S2, the (meth)acrylate monomers G with different structures in the present application can be prepared. Then, the reactants corresponding to G with different structures in the present application are shown in Table 1 below.

[0152] Table 1 Reactants and refractive index corresponding to G of different structural formulas

[0153]

[0154] The organic solvent, the first photoinitiator and the acid binding agent in this embodiment are only used for illustrative description and cannot be understood as limiting the present application. The organic solvent can be one or more of ethanol, petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, acetonitrile, N,N-dimethylformamide or dimethyl sulfoxide. The first photoinitiator can be at least one of (2,4,6-trimethylbenzoyl chloride) diphenylphosphine oxide, 2,4,6-trimethylbenzoylphosphonic acid ethyl ester, 2-methyl-1-[4-methylthiophenyl]-2-morpholinyl-1-propanone, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin dimethyl ether, methyl o-benzoylbenzoate, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone, bis-2,6-difluoro-3-pyrrolephenyl dititanium, and ethyl 4-dimethylamino-benzoate. The acid binding agent includes at least one of triethylamine, pyridine, N,N-diisopropylethylamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, potassium carbonate, ammonium carbonate, and sodium carbonate. Those skilled in the art should understand that these should all be within the protection scope of the present invention.

[0155] Example 2

[0156] Photopolymer holographic recording media 2-1 to 2-13 containing the (meth)acrylate monomers of Examples 1-1 to 1-13 were used: the specific components of the photopolymer holographic recording media 2-1 to 2-13 are shown in Table 2 below.

[0157] Table 2 Composition of each photopolymer type holographic recording medium containing the (meth)acrylate monomer of each example

[0158]

[0159]

[0160]

[0161] In this embodiment, the components selected may also be other components listed above, and these embodiments should not be construed as limiting the scope of protection of the present invention.

[0162] Comparative Example

[0163] The composition of the photopolymer holographic recording medium 2-1 is substantially the same as that of Example 2, except that the (meth)acrylate monomer G1-a of the photopolymer holographic recording medium 2-1 is removed so that the proportion of the (meth)acrylate monomer becomes 0, while the polymerizable monomer 2-vinylnaphthalene is increased to 50 parts, thereby obtaining a conventional photopolymer holographic recording medium.

[0164] Test example

[0165] Holographic performance test: The performance of the photopolymer holographic recording media 2-1 to 2-13 containing (meth)acrylate monomers in Example 2 and the ordinary photopolymer holographic recording medium in the comparative example were tested, and the results are shown in Table 3. During the test, the various holographic recording media in Example 2 were exposed to lasers of different wavelengths according to different photosensitive systems, and the exposure intensity was 3 mW / cm 2 .

[0166] The corresponding holographic performance graphs were plotted using the photopolymer holographic recording medium 2-1 containing (meth)acrylate monomers, the photopolymer holographic recording medium 2-2 containing (meth)acrylate monomers, and the photopolymer holographic recording medium 2-3 containing (meth)acrylate monomers in Example 2 to obtain Figure 1 .

[0167] Specifically, for the three holographic recording media 2-1, 2-2, and 2-3, solid-state lasers with wavelengths of 633nm, 457nm, and 532nm are used as light sources, respectively. After the beam expander, beam splitter, and half-wave plate, two beams with the same light intensity and a diameter of 8mm are obtained. The two beams intersect in the prepared holographic recording medium for exposure, and the light intensity is 3mW / cm 2 The detection light source is a 785nm wavelength solid 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 the photodetector. The single grating diffraction efficiency (η) of the photopolymer holographic recording medium and the photosensitivity (S) of the photopolymer holographic recording medium are calculated by formulas (1) to (3).

[0168]

[0169] Where 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 photosensitivity, E is the exposure energy, and ΔE is the exposure energy when the highest diffraction efficiency is achieved.

[0170] like Figure 1 As shown in the figure, it is finally measured that the diffraction efficiency of the photopolymer holographic recording medium of the present invention is greater than 95%, and the exposure amount is less than 20mJ / cm 2 , sensitivity greater than 100cm 2 / mJ.

[0171] And as Figure 2 As shown, the conventional photopolymer holographic recording medium of the comparative example was exposed at an exposure wavelength of 633 nm and an exposure light intensity of 3 mW / cm 2 The diffraction efficiency of the ordinary photopolymer holographic recording medium in the comparative example is less than 50%, and the required exposure is greater than 100 mJ / cm 2 , the sensitivity is low, its sensitivity is less than 10cm 2 / mJ.

[0172] The holographic performance tests of the photopolymer holographic recording media 2-1 to 2-13 in Example 2 and the common photopolymer holographic recording media of the comparative example are shown in Table 3 below.

[0173] Table 3 Holographic performance test table of each photopolymer holographic recording medium in Example 2 and Comparative Example

[0174]

[0175] Solubility test of (meth)acrylate monomers with different n values ​​in photopolymer holographic recording media: By testing the haze of photopolymer holographic recording media containing different added amounts of high-refractive-index (meth)acrylate monomers, it is stipulated that the haze is completely miscible when it is less than 1%, thereby evaluating the solubility of the monomers in the photopolymer with different n values.

[0176] Then, when the value of n in the methacrylate monomer is 1, 5, 10, 15, and 20 respectively, the solubility of the (meth)acrylate monomer of the photopolymer holographic recording media 2-1 to 2-13 containing the (meth)acrylate monomer in Example 2 is tested, and the test results are shown in Table 4.

[0177] As shown in Table 4, the solubility of the (meth)acrylate monomer in the photopolymer is different when the n value is different, and the solubility of the (meth)acrylate monomer in the photopolymer is greater when the n value is larger. When the n value is 1, the solubility of the (meth)acrylate monomer in the photopolymer is generally higher than 20%. Therefore, the solubility of the (meth)acrylate monomer in the photopolymer is relatively large, and a large amount of (meth)acrylate monomer can be added without precipitation, so that the addition amount of the (meth)acrylate monomer of the present invention can reach a certain level, which is beneficial to the writing monomer of the present invention to improve its refractive index, thereby further improving the refractive index difference between the writing monomer and the film-forming resin, and finally improving the holographic performance of the photopolymer type holographic recording medium containing the (meth)acrylate monomer of the present invention.

[0178] Table 4 Solubility of different monomers in photopolymer holographic recording media

[0179]

[0180] In summary, reference Figure 1 , Figure 2 As shown in Table 3, the diffraction efficiency of the photopolymer holographic recording medium of the embodiment of the present invention is much higher than that of the comparative example, the sensitivity is much higher than that of the comparative example, and the required exposure amount is small. Referring to Table 4, the (meth)acrylate monomer of the embodiment of the present invention can be added in a considerable amount to the photopolymer holographic recording medium without precipitation, and has good solubility.

[0181] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A (meth)acrylate monomer, characterized in that: Its general structure is shown below: wherein n is an integer of 1 to 20, R1 is methyl or hydrogen; R2 and R3 are selected from hydrogen, Br, phenyl, methyl or in A1 in which is phenyl or methyl.

2. The (meth)acrylate monomer according to claim 1, characterized in that The (meth)acrylate monomer is selected from monomers having the following structural formula: Wherein R1 is methyl or hydrogen, and n is an integer from 1 to 10.

3. A method for preparing a (meth)acrylate monomer according to claim 1 or 2, characterized in that: The following steps are involved: Dissolving compound P1 and compound M1 in an organic solvent, adding a first photoinitiator, and reacting under light to obtain compound P2; The compound P2 and the acid-binding agent are completely mixed in an organic solvent, and the compound M2 is added until the reaction is complete, and the excess reactants and the solvent are removed to separate and obtain the (meth)acrylate monomer; The general structural formula of the compound P1 is: R2, R3 are selected from hydrogen, Br, phenyl, methyl or A1 is phenyl or methyl; The structural formula of the compound M1 is Wherein n is an integer from 1 to 20; The compound M2 is Wherein R1 is methyl or hydrogen.

4. The method for preparing a (meth)acrylate monomer according to claim 3, characterized in that: The molar ratio of the compound P1, the compound M1 and the first photoinitiator is 1:(0.2-0.5):(0.01-0.03); and / or, The light intensity is 5 to 300 mW / cm 2 , the wavelength of the light is 200 to 405 nm, the reaction time under the light is 1 h to 3 h, and the first photoinitiator is an ultraviolet light initiator; and / or, The molar ratio of the compound P2, the acid-binding agent and the compound M2 is 1:(1-2):(1-2); and / or, When the compound P2, the acid-binding agent and the compound M2 react, the reaction temperature is controlled at 0°C; and / or, The solvent includes ethanol, petroleum ether, dichloromethane, chloroform, ethyl acetate, tetrahydrofuran, acetonitrile, N,N-dimethylformamide or dimethyl sulfoxide.

5. The method for preparing a (meth)acrylate monomer according to claim 3, characterized in that: The compound P1 is selected from compounds having the following structural formula: The first photoinitiator includes at least one of (2,4,6-trimethylbenzoyl chloride) diphenylphosphine oxide, 2,4,6-trimethylbenzoylphosphonic acid ethyl ester, 2-methyl-1-[4-methylthiophenyl]-2-morpholinyl-1-propanone, 1-hydroxy-cyclohexyl-phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, benzoin dimethyl ether, methyl o-benzoylbenzoate, phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide, 2-hydroxy-1-(4-(2-hydroxy-2-methylpropionylphenyl)benzyl)-2-methyl-1-propanone, bis-2,6-difluoro-3-pyrrolphenyl titanocene, and 4-dimethylamino-ethyl benzoate; and / or, The acid binding agent includes at least one of triethylamine, pyridine, N,N-diisopropylethylamine, 4-dimethylaminopyridine, tetrabutylammonium bromide, potassium carbonate, ammonium carbonate and sodium carbonate.

6. A photopolymer holographic recording medium containing the (meth)acrylate monomer according to claim 1 or 2, characterized in that: The invention comprises a writing monomer, wherein the writing monomer comprises the (meth)acrylic acid ester monomer and a polymerizable monomer.

7. The photopolymer holographic recording medium according to claim 6, wherein: The weight percentage of the writing monomer in the entire photopolymer holographic recording medium is: 30% to 60%; The photopolymer holographic recording medium further comprises a film-forming resin, a photosensitive initiator assembly agent, a chain transfer agent, a catalyst and additives. The film-forming resin comprises a compound having a plurality of isocyanate-reactive functional groups and a polyisocyanate-based compound.

8. The photopolymer holographic recording medium according to claim 7, wherein: The composition comprises the following components in parts by weight: First component: 20 to 50 parts of a compound having multiple isocyanate-reactive functional groups; The second component: 10 to 40 parts of polyisocyanate compound; The third component: 3 to 30 parts of (meth)acrylate monomer; The fourth component: 0.1 to 47 parts of polymerizable monomer; The fifth component: 0.1 to 4 parts of photosensitive initiator combination agent; The sixth component: 0.1 to 3 parts of chain transfer agent; The seventh component: 0.1 to 3 parts of catalyst; The eighth component: 0.1 to 7 parts of additives.

9. The photopolymer holographic recording medium according to claim 7, wherein: The composition comprises the following components in parts by weight: First component: 25 to 35 parts of a compound having multiple isocyanate-reactive functional groups; The second component: 15 to 25 parts of polyisocyanate compound; The third component: 3 to 15 parts of (meth)acrylate monomer; The fourth component: 25 to 40 parts of polymerizable monomer; The fifth component: 0.3 to 3 parts of photosensitive initiator combination agent; The sixth component: 0.5 to 2 parts of chain transfer agent; The seventh component: 0.5 to 2 parts of catalyst; The eighth component: 0.6 to 6 parts of additives.

10. The photopolymer holographic recording medium according to any one of claims 7 to 9, characterized in that: In the compound having a plurality of isocyanate-reactive functional groups, the isocyanate-reactive functional groups are hydroxyl and thiol; and / or, The compound having multiple isocyanate-reactive functional groups is selected from 2-ethyl-1,3-hexanediol, 1,2,4-butanetriol, 1,6-hexanediol, 2,5-hexanediol, 1,4-cyclohexanediol, 1,8-octanediol, 1,7-heptanediol, 1,3-butanediol, 1,5-pentanediol, 1,4-cyclohexanedimethanol, 1,3-cyclopentanediol, tetraethylene glycol, trimethylolethane, trimethylolpropane, glycol At least one of oil, triethanolamine, polyester polyol with a molecular weight of 100 to 2000, polycarbonate polyol, polyether polyol, 2,3-dithio (2-mercapto) -1-propanethiol, 1,2-octanedithiol, 2,5-dimethylmercapto-1,4-dithiane, 1,2-butanethiol, 1,3-butanethiol, 3,7-dithia-1,9-nonanethiol, 2,3-butanethiol; and / or, The polyisocyanate-based compound is a compound with a low refractive index and two or more isocyanate groups; and / or, The polymerizable monomer is selected from at least one of alkenyl naphthalene compounds, alkenyl anthracene compounds, alkenyl benzene compounds, acrylic compounds, methacrylic compounds, acrylate compounds, methacrylate compounds, N-vinyl pyrrole, N-vinyl carbazole, N-vinylimidazole, N-vinyl indole, N-vinyl pyrrolidone, and trans-N-3-ynyl butenyl carbazole; and / or, The photosensitive initiator combination comprises a photosensitizer and a second photoinitiator; the mass ratio of the photosensitizer to the second photoinitiator is (0.001-1):(0.1-3); the absorption wavelength of the photosensitizer selected in the photosensitive initiator combination and the absorption wavelength range of the second photoinitiator are different; and / or, The chain transfer agent is a thiol compound; and / or, The catalyst is a tertiary amine catalyst or an organic metal catalyst; and / or, The additives include one or more of a defoamer, a leveling agent, a plasticizer and a water remover.

11. A holographic optical element, characterized in that: The raw material of the holographic optical element comprises the photopolymer holographic recording medium as claimed in any one of claims 6 to 10.

12. An optical device, characterized in that: Comprising the holographic optical element as claimed in claim 11.

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