Photopolymer holographic recording medium and preparation method and application thereof

Abstract

The present invention discloses a photopolymer holographic recording medium and a preparation method and application thereof, wherein the photopolymer holographic recording medium comprises a film-forming resin, the film-forming resin comprises a first component and a second component, the first component is cellulose acetate, and the second component is polyisocyanate; the cellulose acetate contains active hydroxyl groups. In the photopolymer holographic recording medium disclosed by the present invention, polyisocyanate reacts with hydroxyl groups in cellulose acetate to generate a three-dimensional cross-linked network compound, thereby improving the linear structure of cellulose acetate into a network structure, and improving the dimensional stability and thermal stability of the improved cellulose acetate. The photopolymer holographic recording medium made of the film-forming resin formed by the improved cellulose acetate has good high temperature resistance, low temperature resistance, cold and heat shock resistance, and ultraviolet radiation resistance, and can be used for a long time.

Description

Technical Field

[0001] The invention relates to the technical field of holographic materials, in particular to a photopolymer holographic recording medium and a preparation method and application thereof. Background Art

[0002] The 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 medium is good or not. Cellulose acetate is often used as a component of the film-forming resin in existing photopolymers. However, cellulose acetate is mainly a linear polymer. The volume holographic grating prepared by the photopolymer using cellulose acetate as the film-forming resin has poor weather resistance and cannot be used for a long time. Summary of the invention

[0003] In view of this, the present invention proposes a photopolymer holographic recording medium and a preparation method and application thereof, aiming to achieve high diffraction efficiency and good weather resistance of the photopolymer holographic recording medium.

[0004] The photopolymer holographic recording medium proposed in the first aspect of the present invention comprises a film-forming resin, wherein the film-forming resin comprises a first component and a second component, wherein the first component is cellulose acetate and the second component is polyisocyanate; and the cellulose acetate contains active hydroxyl groups.

[0005] It can be seen from the above technical scheme that the polyisocyanate of the present invention reacts with the hydroxyl group in cellulose acetate to generate a three-dimensional cross-linked compound, thereby improving the linear structure of cellulose acetate into a network structure, thereby improving the dimensional stability and thermal stability of the improved cellulose acetate; and the photopolymer holographic recording medium made of the film-forming resin formed by the cellulose acetate with improved structure has good weather resistance and can be used for a long time.

[0006] In some embodiments of the present invention, the general structural formula of the cellulose acetate is [C6H7O2(OH) 3-m (OOCCH3) m ] n , and the value of m is 0.1-2.8, n is the degree of polymerization and is a positive integer, and the molecular weight of the cellulose acetate is 1000-100000.

[0007] In some embodiments of the present invention, the mass ratio of the first component to the second component is (20-60):(1-24).

[0008] In some embodiments of the present invention, the polyisocyanate is selected from one or more of hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl) tris(hexamethylene) isocyanate, butane-1,4-diisocyanate, 1,4-cyclohexane diisocyanate, 1,4-cyclohexane dimethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, xylene diisocyanate, tetramethyl metaxylene diisocyanate, norbornane diisocyanate, dimethyl biphenyl diisocyanate, methylcyclohexyl diisocyanate, dimethyl diphenylmethane diisocyanate, and lysine diisocyanate.

[0009] In some embodiments of the present invention, the photopolymer holographic recording medium includes the following components in weight proportion: first component: 20 to 60 parts of cellulose acetate; second component: 1 to 24 parts of polyisocyanate; third component: 10 to 60 parts of polymerizable monomers; fourth component: 0.1 to 4 parts of photosensitive initiator combination agent; fifth component: 0.1 to 3 parts of chain transfer agent; sixth component: 0.1 to 3 parts of catalyst; seventh component: 0.1 to 9 parts of additives or solvents.

[0010] In some embodiments 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; and / or, the photosensitive initiator combination includes a photosensitizer and a photoinitiator; or, the photosensitive initiator combination includes a photosensitizer and a co-initiator; and / or, the chain transfer agent is a thiol compound; and / or, the catalyst is a tertiary amine catalyst and an organometallic catalyst; and / or, when the seventh component is an additive, the additive includes one or more of a defoamer, a leveling agent, and a plasticizer.

[0011] In some embodiments of the present invention, the mass ratio of the photosensitizer to the photoinitiator is (0.001-1):(0.1-3); or, the mass ratio of the photosensitizer to the co-initiator is (0.001-1):(0.1-3); and / or, 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; and / or, the photoinitiator is selected from at least one of aromatic ketone compounds, benzoin and its derivatives, benzyl ketals, acylphosphine oxides, aromatic ammonium borates, chromium salts, aromatic diazonium salts, onium salts, and organic metal compounds; and / or, the co-initiator is an amine substance.

[0012] In some specific embodiments of the present invention, the defoaming agent is a silicone defoaming agent and / or a polymer defoaming agent not containing silicone, and the weight percentage of the defoaming agent in the photopolymer holographic recording medium is less than or equal to 3 parts; and / or, the leveling agent is a silicone surface additive, and the weight percentage of the leveling agent in the photopolymer holographic recording medium is less than or equal to 3 parts; and / or, the plasticizer is selected from at least one of toluene, xylene, dimethylformamide, dimethylacetamide, glycerol, and phthalates, and the weight percentage of the plasticizer in the photopolymer holographic recording medium is less than or equal to 3 parts.

[0013] In some embodiments of the present invention, when the seventh component is a solvent, the weight percentage of the solvent in the photopolymer holographic recording medium is less than or equal to 3 parts; and / or the solvent is selected from at least one of dichloromethane, ethyl acetate, petroleum ether, n-hexane, toluene, xylene, N,N-dimethylformamide, N,N-dimethylacetamide, ether, pentane, acetone, dichloroethane, chloroform, methanol, tetrahydrofuran, trichloroethane, carbon tetrachloride, ethanol, butanone, benzene, cyclohexane, acetonitrile, isopropanol, ethylene glycol dimethyl ether, propionitrile, heptane, pyridine, butanol, ethylene glycol monomethyl ether, octane, butyl acetate, chlorobenzene, ethylene glycol monoethyl ether, cyclohexanone, and dimethyl sulfoxide.

[0014] The second aspect of the present invention proposes a method for preparing the photopolymer holographic recording medium in the aforementioned multiple examples, comprising the following steps: weighing the raw materials of each component of the photopolymer holographic recording medium into a container, and stirring thoroughly until all the components are dissolved; filtering with a filter membrane to obtain a mixture; coating the mixture on a substrate, and obtaining the photopolymer holographic recording medium after drying.

[0015] The preparation method of the photopolymer holographic recording medium proposed in the second aspect of the present invention has few preparation steps, simple operation, easy implementation conditions, and is convenient for obtaining a photopolymer holographic recording medium with high photosensitivity, high diffraction efficiency and good weather resistance.

[0016] In some embodiments of the present invention, the drying is carried out in a dark room at a humidity of 10% to 85% and a temperature of 20° C. to 50° C.; and / or the photosensitivity of the photopolymer holographic recording medium is greater than 100 cm 2 / mJ.

[0017] A third 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 each of the above examples.

[0018] The holographic optical element provided in the third aspect of the present invention maintains good holographic performance during long-term use and has little change in holographic performance when used under different weathering conditions.

[0019] A fourth aspect of the present invention provides an optical device, comprising the holographic optical element as described above.

[0020] The optical device proposed in the fourth aspect of the present invention, such as a head-up display device, an augmented reality device, a virtual reality device, a photopolymer holographic storage disc, etc., has excellent holographic performance and little change in holographic performance after long-term use.

[0021] 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

[0022] 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.

[0023] Figure 1 This is the curve of the grating diffraction efficiency change after 80 days of high temperature treatment;

[0024] Figure 2 This is the curve of the grating diffraction efficiency change after 80 days of low temperature treatment;

[0025] Figure 3 This is the curve of grating diffraction efficiency change after 80 days of cold and hot shock;

[0026] Figure 4 This is the curve of grating diffraction efficiency change after 80 days of UV aging. DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] The present invention provides a cellulose acetate modified with polyisocyanate as a film-forming resin with good dimensional stability and thermal stability, so that the volume holographic grating has high photosensitivity, good weather resistance and a diffraction efficiency higher than 90%.

[0030] In the absence of conflict, the following embodiments and features of the embodiments may be combined with each other.

[0031] Next, the photopolymer type holographic recording medium of the present invention will be described.

[0032] The photopolymer holographic recording medium proposed in the present invention includes a film-forming resin, which includes a first component and a second component, wherein the first component is cellulose acetate and the second component is polyisocyanate; the cellulose acetate contains active hydroxyl groups. It should be noted that the cellulose acetate here is a man-made fiber obtained by esterification reaction using acetic acid and cellulose as raw materials. It can be monoacetyl cellulose, diacetyl cellulose, or triacetyl cellulose, that is, the degree of esterification reaction between acetic acid and cellulose is different, and the more acetic acid is contained, the less hydroxyl groups are contained in the cellulose acetate.

[0033] As can be seen from the above technical solution, the polyisocyanate of the present invention reacts with the hydroxyl group in cellulose acetate to generate a three-dimensional cross-linked network compound, thereby improving the linear structure of cellulose acetate into a network structure, thereby improving the dimensional stability and its own thermal stability; and the photopolymer type holographic recording medium made of the film-forming resin formed by the cellulose acetate with improved structure has good weather resistance, such as good high temperature resistance, low temperature resistance, cold and heat shock resistance, and ultraviolet (UV, Ultraviolet Rays) irradiation resistance, and can be used for a long time.

[0034] In some embodiments of the present invention, the general structural formula of cellulose acetate is:

[0035] [C6H7O2(OH) 3-m (OOCCH3) m ] n , where n represents the degree of polymerization and is a positive integer. In the present invention, the value of m is 0.1 to 2.8; the molecular weight of cellulose acetate is 1000 to 100000. Then, the cellulose acetate in the present invention contains some hydroxyl groups that are not acetated and can react with polyisocyanates. For example, the value of m is 0.1, 0.2, 0.3, 0.5, 0.8, 1.0, 1.5, 2.0, 2.2, 2.6, 2.8, etc.; for another example, the molecular weight of cellulose acetate is 1000, 1100, 1200, 1300, 1400, 1500, 2000, 5000, 10000, 20000, 30000, 50000, 80000, 100000, etc.

[0036] In some specific examples, m is selected to be 0.5 to 2, such as 0.5, 0.8, 1.0, 1.5, 2.0, etc.; and the molecular weight of the entire cellulose acetate molecule is controlled between 3000 and 20000, such as 3000, 4000, 5000, 10000, 20000, etc. Then, in these examples, cellulose acetate will contain more active unesterified hydroxyl groups, which can be used to react with polyisocyanate to form a three-dimensional cross-linked structure.

[0037] In addition, the cellulose acetate of the present invention has a lower refractive index. As a component of the film-forming resin, it is beneficial to make the refractive index of the film-forming resin lower, so that the film-forming resin and the writing monomer form a certain refractive index difference, which is convenient for forming a phase-type volume holographic grating with refractive index modulation.

[0038] In some embodiments of the present invention, the mass ratio of the first component to the second component is (20-60):(1-24). For example, it can be 20:1, 30:2, 40:5, 50:10, 60:20, that is, when the value of n is smaller, the value of m is larger, the hydroxyl groups contained in the cellulose acetate are smaller, and the required polyisocyanate is smaller. At this time, the ratio of the two is closer to 20:1; and when the value of n is larger, the value of m is smaller, the hydroxyl groups contained in the cellulose acetate are more, and the more hydroxyl groups that can react on a single cellulose acetate, the more polyisocyanate is required. At this time, the ratio of the two is closer to 60:20 (that is, 3:1). The hydroxyl groups in the cellulose acetate in the present invention can be completely reacted with the polyisocyanate, or part of the hydroxyl groups can react with the polyisocyanate.

[0039] In some embodiments of the present invention, the polyisocyanate is selected from one or more of hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl) tris(hexamethylene) isocyanate, butane-1,4-diisocyanate, 1,4-cyclohexane diisocyanate, 1,4-cyclohexane dimethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, xylene diisocyanate, tetramethyl metaxylene diisocyanate, norbornane diisocyanate, dimethyl biphenyl diisocyanate, methylcyclohexyl diisocyanate, dimethyl diphenylmethane diisocyanate, and lysine diisocyanate.

[0040] In some embodiments of the present invention, the photopolymer holographic recording medium includes the following raw materials of various components in parts by weight:

[0041] First component: 20 to 60 parts of cellulose acetate, for example, 20 parts, 30 parts, 40 parts, 50 parts, 60 parts, etc.

[0042] Second component: 1 to 24 parts of polyisocyanate, for example, 1 part, 2 parts, 3 parts, 5 parts, 10 parts, 15 parts, 20 parts, 22 parts, 24 parts, etc.

[0043] The third component: 10 to 60 parts of polymerizable monomers, for example, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, 50 parts, 60 parts, etc.

[0044] The fourth component: 0.1 to 4 parts of the photosensitive initiator combination agent, for example, 0.1, 0.2, 0.3, 0.5, 1, 1.5, 2.0, 2.5, 3.0, 3.5, 4, etc.

[0045] The fifth 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.

[0046] Sixth 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.

[0047] The seventh component: 0.1 to 9 parts of additives or solvents, 0.1, 0.2, 0.3, 0.5, 1, 1.5, 2, 3, 4, 5, 6, 7, 8, 9, etc.

[0048] It is understandable that the present invention can achieve full synergistic effect of the components 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 too much or too little of a certain component, thereby ensuring that the comprehensive holographic performance of the final photopolymer holographic recording medium is better.

[0049] For example, by controlling the cellulose acetate to 20 to 60 parts and the polyisocyanate to 1 to 24 parts, the first component and the second component can jointly form a film-forming resin, thereby providing support for the other components, and the film-forming resin composed of the above components of the present application has good thermal stability and good dimensional stability.

[0050] By controlling the polymerizable monomer to 10 to 60 parts, the polymerizable monomer can form a writing monomer with a higher refractive index. Then the first component, the second component and the third component provide a material basis for forming a volume holographic grating with refractive index modulation.

[0051] For example, by controlling the photosensitive initiator composition to 0.1 to 4 parts, it can absorb an appropriate number of photons during exposure and control the polymerization reaction at a certain speed, so that the grating can 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.

[0052] For example, by controlling the chain transfer agent to 0.1 to 3 parts, the polymer chain length can be controlled within a certain reasonable range and the degree of polymerization can be effectively prevented, thereby ensuring that the final holographic recording medium has the required optical properties and diffraction efficiency.

[0053] For example, controlling the catalyst at 0.1 to 3 parts can effectively increase the reaction rate of related components and the consumption rate of related components after exposure, thereby quickly forming a concentration difference between the monomers in the bright and dark areas and realizing a refractive index modulated phase-type volume holographic grating.

[0054] For example, controlling the additive or solvent to 0.1 to 9 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. If the number of solvents is controlled within the above range, the solvent can fully wet other components, and each component can be mutually soluble to form a relatively uniform mixed system, which is convenient for coating and making photopolymer holographic recording media.

[0055] In some optional examples, the photopolymer holographic recording medium includes the following components in parts by weight: a first component - 20 parts of cellulose acetate, a second component - 17 parts of polyisocyanate, a third component - 50 parts of polymerizable monomers, a fourth component - 2 parts of photosensitive initiator composition, a fifth component - 1 part of chain transfer agent, a sixth component - 3 parts of catalyst, and a seventh component - 7 parts of additives.

[0056] In some optional examples, the photopolymer holographic recording medium includes the following components in parts by weight: a first component - 30 parts of cellulose acetate, a second component - 24 parts of polyisocyanate, a third component - 40 parts of polymerizable monomers, a fourth component - 2 parts of photosensitive initiator composition, a fifth component - 0.3 parts of chain transfer agent, a sixth component - 0.4 parts of catalyst, and a seventh component - 3 parts of additives.

[0057] In some optional examples, the photopolymer holographic recording medium includes the following components in parts by weight: a first component - 40 parts of cellulose acetate, a second component - 18.7 parts of polyisocyanate, a third component - 37 parts of polymerizable monomers, a fourth component - 1.3 parts of photosensitive initiator composition, a fifth component - 1 part of chain transfer agent, a sixth component - 1 part of catalyst, and a seventh component - 1 part of additive.

[0058] In some optional examples, the photopolymer holographic recording medium includes the following components in parts by weight: a first component - 50 parts of cellulose acetate, a second component - 15.7 parts of polyisocyanate, a third component - 30 parts of polymerizable monomers, a fourth component - 1 part of photosensitive initiator composition, a fifth component - 0.1 parts of chain transfer agent, a sixth component - 1.3 parts of catalyst, and a seventh component - 1.9 parts of solvent.

[0059] In some optional examples, the photopolymer holographic recording medium includes the following components in parts by weight: a first component - 57.7 parts of cellulose acetate, a second component - 4 parts of polyisocyanate, a third component - 32 parts of polymerizable monomers, a fourth component - 1 part of photosensitive initiator composition, a fifth component - 1 part of chain transfer agent, a sixth component - 0.1 parts of catalyst, and a seventh component - 1.9 parts of solvent.

[0060] In some optional examples, the photopolymer holographic recording medium includes the following components in parts by weight: a first component - 60 parts of cellulose acetate, a second component - 20 parts of polyisocyanate, a third component - 10 parts of polymerizable monomers, a fourth component - 1 part of photosensitive initiator composition, a fifth component - 1 part of chain transfer agent, a sixth component - 1 part of catalyst, and a seventh component - 7 parts of additives.

[0061] In some optional examples, the photopolymer holographic recording medium includes the following components in parts by weight: a first component - 42 parts of cellulose acetate, a second component - 4 parts of polyisocyanate, a third component - 50 parts of polymerizable monomers, a fourth component - 2 parts of photosensitive initiator composition, a fifth component - 0.2 parts of chain transfer agent, a sixth component - 1 part of catalyst, and a seventh component - 0.8 parts of solvent.

[0062] In some optional examples, the photopolymer holographic recording medium includes the following components in parts by weight: a first component - 22 parts of cellulose acetate, a second component - 1 part of polyisocyanate, a third component - 58 parts of polymerizable monomers, a fourth component - 4 parts of photosensitive initiator composition, a fifth component - 3 parts of chain transfer agent, a sixth component - 3 parts of catalyst, and a seventh component - 9 parts of additives.

[0063] In some optional examples, the photopolymer holographic recording medium includes the following components in parts by weight: a first component - 30 parts of cellulose acetate, a second component - 11 parts of polyisocyanate, a third component - 46 parts of polymerizable monomers, a fourth component - 2 parts of photosensitive initiator composition, a fifth component - 2 parts of chain transfer agent, a sixth component - 3 parts of catalyst, and a seventh component - 6 parts of additives.

[0064] In some embodiments 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.

[0065] In some optional embodiments of the present invention, the alkenyl naphthalene compound is selected from at least one of 1-vinyl naphthalene and 2-vinyl naphthalene.

[0066] In some optional embodiments of the present invention, the alkenyl anthracene compound is selected from at least one of 2-vinyl anthracene and 9-vinyl anthracene.

[0067] In some optional embodiments of the present invention, 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.

[0068] In some optional embodiments of the present invention, the methacrylic compound includes at least one of methacrylic acid and its derivatives.

[0069] In some optional embodiments of the present invention, 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. When there are multiple types, they can be combined in any proportion.

[0070] In some optional embodiments of the present invention, 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. When there are multiple types, they can be combined in any proportion.

[0071] In some examples of the present invention, the photosensitive initiator combination includes a photosensitizer and a photoinitiator. The photosensitizer can be matched with a 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 photoinitiator, so that the photoinitiator can be activated under more frequency light radiation 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.

[0072] Then, it can be understood that in other examples, when the present invention uses a wavelength-adapted photoinitiator, no photosensitizer may be added. For example, when the photoinitiator is titanocene (Irgacure 784), no photosensitizer may be added. It is an orange solid photoinitiator with extremely high reactivity, which can initiate the polymerization reaction of unsaturated resin under the action of visible light or ultraviolet light.

[0073] In some 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 benzylcycloalkane ketone compounds.

[0074] More specifically, the photosensitizer is selected from one or more of new methylene blue, thionine, basic yellow, chlorinated pinacol cyanol, rhodamine 6G, eosin, erythrosine, gallocyanine, ethyl violet, Victoria blue R, lapis lazuli blue, methylene blue, basic orange, daro red, pyrrole red Y, basic red 29, quinaldine red, crystal violet, ethyl violet, brilliant green, azure A, crystal violet white nitrile, and malachite green white nitrile. In the present invention, different broadband responses can be achieved by regulating the types of photosensitizers. Photosensitizers are dyes with high electron transfer efficiency under illumination.

[0075] In some examples, the photoinitiator is selected from at least one of aromatic ketone compounds, benzoin and its derivatives, benzil ketal, acylphosphine oxide, aryl ammonium borate, chromium salt, aryl diazonium salt, onium salt, and organic metal compound. It can also be other photoinitiators with similar functions, which are not limited in the present invention.

[0076] In some specific examples, the photoinitiator is selected from one or more of benzophenone, alkylbenzophenone, 4,4'-bis(dimethylamino)benzophenone, anthrone and halogenated benzophenone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bisacylphosphine oxide, phenyl dihydroxyacetate, camphorquinone, α-aminoalkylphenone, α,α-dialkoxyacetophenone, α-hydroxyalkylphenone, triphenylhexyl borate tetrabutylammonium, tri-(3-fluorophenyl)hexyl borate tetrabutylammonium, tri-(3-chloro-4-methylphenyl)hexyl borate tetrabutylammonium, ferrocenyl compounds, iodonium salts, sulfonium salts, hexaarylbisimidazole, etc. When these photoinitiators are irradiated with light within the corresponding wavelength range, they can be quickly activated and generate active free radicals, thereby initiating polymerization reactions between the components of the photopolymer holographic recording medium to achieve a difference in monomer concentration between the bright area and the dark area.

[0077] In some examples, the mass ratio of photosensitizer to photoinitiator is (0.001-1):(0.1-3). By controlling the mass ratio of photosensitizer to photoinitiator within the above range, the concentration of 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 polymerization reaction is controlled within a reasonable range, and the speed of grating formation is controlled within a certain range, so as to ensure the light transmittance of the photopolymer holographic recording medium and obtain excellent diffraction efficiency. In a more specific example, the mass of photosensitizer is 1 / 10 to 1 / 3 of the mass of photoinitiator, such as 1 / 10, 1 / 9, 1 / 8, 1 / 7, 1 / 6, 1 / 5, 1 / 4 or 1 / 3, etc.

[0078] In some other examples of the present invention, the photosensitive initiator combination includes a photosensitizer and a co-initiator.

[0079] In some examples, the types and functions of the photosensitizers are similar to the types and functions of the aforementioned photosensitizers and are not described in detail here.

[0080] In some examples, the co-initiator is an amine substance. The co-initiator can participate in the reaction, generate free radicals or heat, and make the entire reaction reach the required conditions, thereby inducing the chemical reaction to proceed.

[0081] In some specific examples, the co-initiator is selected from at least one of ethylenediamine, propylenediamine, isopropylenediamine, urea oxide, triethanolamine, triisopropanolamine, N-methyldiethanolamine, N,N-dimethylaniline and variants thereof, N-phenylglycine, and L-cysteine.

[0082] In some examples, the mass ratio of the photosensitizer to the co-initiator is (0.001-1):(0.1-3). By controlling the mass of the photosensitizer and the co-initiator within the above range, the progress of the entire reaction can be controlled within a reasonable range. In a more specific example, the mass of the photosensitizer is 1 / 10 to 1 / 3 of the mass of the co-initiator, such as 1 / 10, 1 / 9, 1 / 8, 1 / 7, 1 / 6, 1 / 5, 1 / 4 or 1 / 3, etc.

[0083] In some examples of the present invention, the chain transfer agent is a thiol compound.

[0084] 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.

[0085] In some examples of the present invention, the catalyst is a tertiary amine catalyst and an organometallic catalyst.

[0086] 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.

[0087] In some examples of the present invention, the additive includes one or more of a defoamer, a leveling agent, and a plasticizer.

[0088] 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.

[0089] 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. BYK series defoamers have excellent defoaming performance, good compatibility with other components, and good dispersibility; BYK-011, BYK-012, BYK-014 and BYK-051N are polymer defoamers without silicone. DC65 is a water-based ink that dries quickly, has good printing effect, and is not easy to fall off. AFE-7820 has high efficiency in defoaming performance.

[0090] 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 parts. 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.

[0091] 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 increases the plasticity of the polymer by inserting between polymer molecular chains, weakening the stress between molecules, increasing the mobility of molecular chains, and reducing crystallinity.

[0092] In some embodiments of the present invention, when the seventh component is a solvent, the weight percentage of the solvent in the photopolymer holographic recording medium is less than or equal to 3 parts.

[0093] In a specific embodiment, the solvent is selected from at least one of dichloromethane, ethyl acetate, petroleum ether, n-hexane, toluene, xylene, N,N-dimethylformamide, N,N-dimethylacetamide, ether, pentane, acetone, dichloroethane, chloroform, methanol, tetrahydrofuran, trichloroethane, carbon tetrachloride, ethanol, butanone, benzene, cyclohexane, acetonitrile, isopropanol, ethylene glycol dimethyl ether, propionitrile, heptane, pyridine, butanol, ethylene glycol-methyl ether, octane, butyl acetate, chlorobenzene, ethylene glycol-ethyl ether, cyclohexanone, and dimethyl sulfoxide. These solvents have good compatibility with other components, so that each component is fully dissolved, and the solvent is convenient for subsequent drying and removal.

[0094] Next, a method for preparing the photopolymer type holographic recording medium of the present invention comprising the aforementioned plurality of components will be described.

[0095] The method for preparing the photopolymer holographic recording medium according to the present invention comprises the following steps:

[0096] Step S10: weigh the raw materials of various components of the photopolymer holographic recording medium into a container, and stir them thoroughly until all the components are dissolved.

[0097] Step S20, filtering using a filter membrane to obtain a mixture.

[0098] Step S30: coating the mixture onto a substrate, and obtaining a photopolymer holographic recording medium after drying.

[0099] From the above, it can be seen that the preparation method of the photopolymer holographic recording medium proposed in the present invention has fewer preparation steps, simple operation, easy implementation conditions, and is convenient for obtaining a photopolymer holographic recording medium with high photosensitivity, high diffraction efficiency and good weather resistance.

[0100] In some embodiments of the present invention, the drying is carried out in a dark room with a humidity of 10% to 85% and a temperature of 20° C. to 50° C. The conditions are simple and the operation is easy.

[0101] In some embodiments of the present invention, the photosensitivity of the photopolymer holographic recording medium is greater than 100 cm 2 / mJ.

[0102] Next, the application of the aforementioned photopolymer type holographic recording medium of the present invention will be described.

[0103] 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.

[0104] It can be seen from the above that the holographic optical element proposed in the present invention, because it includes the aforementioned photopolymer holographic recording medium of the present invention, also has the advantages of the photopolymer holographic recording medium of the present invention, and the holographic performance is kept good during long-term use; the holographic performance changes little when used under different weathering conditions (such as high temperature conditions, low temperature conditions, cold and hot shock conditions, and ultraviolet conditions).

[0105] 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.

[0106] 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 and little change in holographic performance after long-term use.

[0107] The photopolymer holographic recording medium of the present invention is described below with reference to specific embodiments.

[0108] Example 1

[0109] In this embodiment, the photopolymer holographic recording medium 1-1 includes the following raw materials of various components in parts by weight:

[0110] The first component: 30 parts of cellulose acetate. In the general structural formula of cellulose acetate, [C6H7O2(OH) 3-m (OOCCH3) m ] n , and the value of m is 1 and n is 5.

[0111] The second component: 24 parts of polyisocyanate; the polyisocyanate is hexamethylene diisocyanate.

[0112] The third component: 40 parts of polymerizable monomer; the polymerizable monomer is 2-vinylnaphthalene.

[0113] The fourth component: 2 parts of photosensitive initiator combination agent; the photosensitive initiator combination agent includes a photosensitizer and a photoinitiator, wherein the photosensitizer new methylene blue is 0.3 parts and the photoinitiator benzophenone is 1.7 parts.

[0114] The fifth component: 0.3 parts of chain transfer agent; the chain transfer agent is 0.3 parts of mercaptoethanol.

[0115] The sixth component: 0.4 parts of catalyst; the catalyst is 0.4 parts of triethylenediamine.

[0116] The seventh component: 3 parts of additives. The additives include defoamers and leveling agents, wherein the defoamer is 1.5 parts of BYK-011 and the leveling agent is 1.5 parts of BYK-302.

[0117] Example 2

[0118] In this embodiment, the photopolymer holographic recording medium 1-2 includes the following raw materials of various components in parts by weight:

[0119] The first component: 20 parts of cellulose acetate. In the general structural formula of cellulose acetate, [C6H7O2(OH) 3-m (OOCCH3) m ] n , and the value of m is 2 and n is 5.

[0120] The second component: 17 parts of polyisocyanate; the polyisocyanate is trimethylhexamethylene diisocyanate.

[0121] The third component: 50 parts of polymerizable monomer; the polymerizable monomer is 4-chlorostyrene.

[0122] The fourth component: 2 parts of photosensitive initiator combination agent; the photosensitive initiator combination agent includes a photosensitizer and a photoinitiator, wherein the photosensitizer ethyl violet is 0.3 parts and the photoinitiator a-aminoalkyl phenone is 1.7 parts.

[0123] The fifth component: 1 part of chain transfer agent; the chain transfer agent is 1 part of dodecyl mercaptan.

[0124] The sixth component: 3 parts of catalyst; the catalyst is 3 parts of bis(dimethylaminoethyl) ether.

[0125] The seventh component: 7 parts of additives. The additives include defoamer, leveling agent and plasticizer, wherein defoamer BYK-085 is taken in 3 parts, leveling agent BYK-329 is taken in 3 parts, and plasticizer phthalate is taken in 1 part.

[0126] Example 3

[0127] In this embodiment, the photopolymer holographic recording medium 1-3 includes the following raw materials of various components in parts by weight:

[0128] The first component: 40 parts of cellulose acetate. In the general structural formula of cellulose acetate, [C6H7O2(OH) 3-m (OOCCH3) m ] n , and the value of m is 1.5 and n is 8.

[0129] The second component: 18.7 parts of polyisocyanate; the polyisocyanate is butane-1,4-diisocyanate.

[0130] The third component: 37 parts of polymerizable monomer; the polymerizable monomer is p-bromophenyl acrylate.

[0131] The fourth component: 1.3 parts of photosensitive initiator combination agent; the photosensitive initiator combination agent includes a photosensitizer and a photoinitiator, wherein the photosensitizer basic yellow is 0.3 parts, and the photoinitiator tris-(3-fluorophenyl)hexyl boric acid tetra-ammonium is 1 part.

[0132] The fifth component: 1 part of chain transfer agent; the chain transfer agent is 1 part of 5-(4-pyridyl)-1,3,4-oxadiazole-2-thiol.

[0133] The sixth component: 1 part of catalyst; the catalyst is 1 part of stannous octoate.

[0134] The seventh component: 1 part of additives. The additives include defoamer, leveling agent and plasticizer, wherein defoamer BYK-1760 is taken in 0.3 parts, leveling agent BYK-3455 is taken in 0.4 parts, and plasticizer dimethylacetamide is taken in 0.3 parts.

[0135] Example 4

[0136] In this embodiment, the photopolymer holographic recording medium 1-4 includes the following raw materials of various components in parts by weight:

[0137] The first component: 50 parts of cellulose acetate. In the general structural formula of cellulose acetate, [C6H7O2(OH) 3-m (OOCCH3) m ] n , and the value of m is 2.5 and n is 10.

[0138] The second component: 15.7 parts of polyisocyanate; the polyisocyanate is (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl)tris(hexamethylene)isocyanate.

[0139] The third component: 30 parts of polymerizable monomer; the polymerizable monomer is p-(bromomethyl)styrene.

[0140] The fourth component: 1 part of photosensitive initiator combination agent; the photosensitive initiator combination agent includes a photosensitizer and a photoinitiator, wherein 0.1 part of lapis lazuli blue and 0.9 part of the photoinitiator tetrabutylammonium triphenylhexylborate.

[0141] The fifth component: 0.1 part of chain transfer agent; the chain transfer agent is 0.1 part of hexanethiol.

[0142] The sixth component: 1.3 parts of catalyst; the catalyst is 1.3 parts of dibutyltin dilaurate.

[0143] The seventh component: 1.9 parts of additives. The additives include defoamer, leveling agent and plasticizer, wherein the defoamer BYK-1707 is taken in 0.4 parts, the leveling agent BYK-358 is taken in 1 parts, and the plasticizer glycerin is taken in 0.5 parts.

[0144] Example 5

[0145] In this embodiment, the photopolymer holographic recording medium 1-5 includes the following raw materials of various components in parts by weight:

[0146] The first component: 60 parts of cellulose acetate. In the general structural formula of cellulose acetate, [C6H7O2(OH) 3-m (OOCCH3) m ] n , and the value of m is 2.8 and n is 15.

[0147] The second component: 4.2 parts of polyisocyanate; the polyisocyanate is 1,4-cyclohexane diisocyanate.

[0148] The third component: 30.8 parts of polymerizable monomer; the polymerizable monomer is 9-vinylanthracene.

[0149] The fourth component: 4 parts of photosensitive initiator combination agent; the photosensitive initiator combination agent includes a photosensitizer and a photoinitiator, the photosensitizer is 1 part of eosin, and the photoinitiator is 3 parts of α-hydroxyalkyl phenone.

[0150] The fifth component: 0.1 part of chain transfer agent; the chain transfer agent is 0.1 part of mercaptoethanol.

[0151] The sixth component: 0.3 parts of a catalyst; the catalyst is 0.3 parts of N,N-bis(dimethylaminopropyl)isopropanolamine.

[0152] The seventh component: 0.6 parts of additives. The additives include defoamers and leveling agents, wherein the defoamer BYK-1610 is taken in 0.1 parts, and the leveling agent BYK-333 is taken in 0.5 parts.

[0153] Example 6

[0154] In this embodiment, the photopolymer holographic recording medium 1-6 includes the following raw materials of various components in parts by weight:

[0155] The first component: 45 parts of cellulose acetate. In the general structural formula of cellulose acetate, [C6H7O2(OH) 3-m (OOCCH3) m ] n , and the value of m is 2.3 and n is 20.

[0156] The second component: 13.5 parts of polyisocyanate; the polyisocyanate is isophorone diisocyanate.

[0157] The third component: 32.5 parts of polymerizable monomer; the polymerizable monomer is p-(chloromethyl)styrene.

[0158] The fourth component: 0.1 parts of a photosensitive initiator composition; the photosensitive initiator composition includes a photoinitiator, and the photoinitiator is titanocene.

[0159] The fifth component: 3 parts of chain transfer agent; the chain transfer agent is 3 parts of dodecyl mercaptan.

[0160] The sixth component: 0.3 parts of catalyst; the catalyst is 0.3 parts of dibutyltin dilaurate.

[0161] The seventh component: 5.6 parts of additives. The additives include defoamers and plasticizers, wherein the defoamer BYK-014 is taken in 3 parts and the plasticizer dimethylformamide is taken in 2.6 parts.

[0162] Example 7

[0163] In this embodiment, the photopolymer holographic recording medium 1-7 includes the following raw materials of various components in parts by weight:

[0164] The first component: 25 parts of cellulose acetate. In the general structural formula of cellulose acetate, [C6H7O2(OH) 3-m (OOCCH3) m ] n , and the value of m is 0.5 and n is 30.

[0165] The second component: 23.8 parts of polyisocyanate; the polyisocyanate is methylcyclohexyl diisocyanate.

[0166] The third component: 42.2 parts of polymerizable monomer; the polymerizable monomer is styrene.

[0167] The fourth component: 2 parts of photosensitive initiator combination agent; the photosensitive initiator combination agent includes a photosensitizer and a co-initiator, wherein the photosensitizer erythrosine is 0.3 parts and the co-initiator propylenediamine is 1.7 parts.

[0168] The fifth component: 1 part of chain transfer agent; the chain transfer agent is 1 part of hexanethiol.

[0169] The sixth component: 3 parts of catalyst; the catalyst is 3 parts of bis(dimethylaminoethyl) ether.

[0170] The seventh component: 3 parts of solvent, which is ethyl acetate.

[0171] Comparative Example

[0172] In this embodiment, the components are substantially the same as those in Example 1, except that the first component cellulose acetate in Example 1 is changed, that is, in the general structural formula of cellulose acetate, [C6H7O2(OH) 3-m(OOCCH3) m ] n , and m is 3, n is 5, and cellulose acetate does not contain active hydroxyl groups. A common photopolymer holographic recording medium is obtained.

[0173] Test example

[0174] The stability of the grating after recording the grating on the holographic recording medium of Examples 1-7 and the comparative example is tested, and the testing method includes the following steps: During the test, according to different photosensitive systems, different wavelengths of lasers can be selected for exposure in Examples 1-7, and Examples 1, 2, and 4 correspond to laser exposure with a wavelength of 633nm; Example 3 selects a laser exposure with a wavelength of 457nm; Examples 5-7 select a laser exposure with a wavelength of 532nm. The following testing method is described by selecting a laser with a corresponding wavelength for the photosensitive system of the photopolymer holographic recording medium in Examples 1, 3, 5, and 7.

[0175] Grating preparation: Use solid lasers with wavelengths of 633nm (Example 1), 457nm (Example 3), and 532nm (Example 5 and Example 7) as light sources, and obtain two beams of 8mm diameter with the same light intensity 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 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, and the single grating diffraction efficiency (η) of the photopolymer holographic recording medium is calculated by formula (1).

[0176]

[0177]

[0178]

[0179] Where η is the diffraction efficiency, I d is the diffracted light, I t For transmitted light.

[0180] High temperature test: Place the grating in an oven and heat treat it at 120°C. Monitor the diffraction efficiency of the grating every 10 days.

[0181] Low temperature test: Place the grating in a thermal shock test chamber and treat it at -80℃. Monitor the diffraction efficiency of the grating every 10 days.

[0182] Thermal shock test: Place the grating in a thermal shock test chamber, treat it at -40℃ for 30min and 80℃ for 30min as one cycle, and monitor the diffraction efficiency of the grating every 10 days.

[0183] Ultraviolet (UV) aging test: Place the grating in a UV aging test chamber at 1W / m 2 The sample was irradiated with a 340nm ultraviolet lamp, with the lamp tube and the center of the sample 50mm apart. One cycle consisted of 4h of UV irradiation at 60℃ and 4h of standing at 50℃ without UV. The grating diffraction efficiency was monitored every 10 days during the cyclic test.

[0184] The holographic performance tests of the photopolymer holographic recording media 1-1 to 1-7 in Examples 1-7 and the common photopolymer holographic recording medium of Comparative Example are shown in Table 1 below.

[0185] Table 1 Holographic performance test table of each photopolymer holographic recording medium in Examples 1-7 and Comparative Examples

[0186]

[0187] Note: The diffraction efficiency reduction value in the table is the initial diffraction efficiency of the grating minus the diffraction efficiency of the grating after 80 days of treatment.

[0188] In summary, the grating diffraction efficiency change curves of the photopolymer holographic recording media in Example 1, Example 3, Example 5, and Example 7 and the ordinary holographic recording media in the comparative example were respectively subjected to high temperature, low temperature, cold and heat shock, and UV aging treatments for 80 days. Figure 1 , Figure 2 , Figure 3 , Figure 4 As shown in Table 1, the diffraction efficiency of the photopolymer holographic recording medium of the embodiment of the present invention is greater than 95%, and the diffraction efficiency changes after 80 days of high-temperature treatment test are much smaller than that of the comparative example, the diffraction efficiency changes after 80 days of low-temperature treatment are much smaller than that of the comparative example, the diffraction efficiency changes after 80 days of cold and hot shock treatment are much smaller than that of the comparative example, and the diffraction efficiency changes after 80 days of ultraviolet aging treatment are much smaller than that of the comparative example. It can be seen that the photopolymer holographic recording medium of the present invention has excellent weather resistance and can be used for a long time.

[0189] 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 photopolymer holographic recording medium, characterized in that: The film-forming resin comprises a first component and a second component, wherein the first component is cellulose acetate and the second component is polyisocyanate; and the cellulose acetate contains active hydroxyl groups.

2. The photopolymer holographic recording medium according to claim 1, wherein: The general structural formula of the cellulose acetate is [C6H7O2(OH) 3-m (OOCCH3) m ] n , and the value of m is 0.1-2.8, n is the degree of polymerization and is a positive integer, and the molecular weight of the cellulose acetate is 1000-100000.

3. The photopolymer holographic recording medium according to claim 1, wherein: The mass ratio of the first component to the second component is (20-60):(1-24).

4. The photopolymer holographic recording medium according to claim 1, wherein: The polyisocyanate is selected from one or more of hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate, (2,4,6-trioxotriazine-1,3,5(2H,4H,6H)-triyl) tris(hexamethylene) isocyanate, butane-1,4-diisocyanate, 1,4-cyclohexane diisocyanate, 1,4-cyclohexane dimethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, toluene diisocyanate, diphenylmethane diisocyanate, naphthalene diisocyanate, p-phenylene diisocyanate, xylylene diisocyanate, tetramethyl metaxylylene diisocyanate, norbornane diisocyanate, dimethyl biphenyl diisocyanate, methylcyclohexyl diisocyanate, dimethyl diphenylmethane diisocyanate, and lysine diisocyanate.

5. The photopolymer holographic recording medium according to any one of claims 1 to 4, characterized in that: The raw materials of each component are included in the following parts by weight: First component: 20 to 60 parts of cellulose acetate; The second component: 1 to 24 parts of polyisocyanate; The third component: 10 to 60 parts of polymerizable monomer; The fourth component: 0.1 to 4 parts of photosensitive initiator combination agent; The fifth component: 0.1 to 3 parts of chain transfer agent; The sixth component: 0.1 to 3 parts of catalyst; The seventh component: 0.1 to 9 parts of additives or solvents.

6. The photopolymer holographic recording medium according to claim 5, wherein: 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 photoinitiator; or, the photosensitive initiator combination comprises a photosensitizer and a co-initiator; and / or, The chain transfer agent is a thiol compound; and / or, The catalyst is a tertiary amine catalyst and an organic metal catalyst; and / or, When the seventh component is an additive, the additive includes one or more of a defoamer, a leveling agent and a plasticizer.

7. The photopolymer holographic recording medium according to claim 6, wherein: The mass ratio of the photosensitizer to the photoinitiator is (0.001-1):(0.1-3); or, the mass ratio of the photosensitizer to the co-initiator is (0.001-1):(0.1-3); and / or, 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; and / or, The photoinitiator is selected from at least one of aromatic ketone compounds, benzoin and its derivatives, benzil ketal, acylphosphine oxide, aryl ammonium borate, chromium salt, aryl diazonium salt, onium salt, and organic metal compound; and / or, The co-initiator is an amine substance.

8. The photopolymer holographic recording medium according to claim 6, wherein: The defoamer is an organosilicon defoamer and / or a polymer defoamer not containing organosilicon, and the weight proportion of the defoamer in the photopolymer holographic recording medium is less than or equal to 3 parts; and / or, 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 parts; and / or, 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 parts.

9. The photopolymer holographic recording medium according to claim 5, wherein: When the seventh component is a solvent, the weight percentage of the solvent in the photopolymer holographic recording medium is less than or equal to 3 parts; and / or, The solvent is selected from at least one of dichloromethane, ethyl acetate, petroleum ether, n-hexane, toluene, xylene, N,N-dimethylformamide, N,N-dimethylacetamide, ether, pentane, acetone, dichloroethane, chloroform, methanol, tetrahydrofuran, trichloroethane, carbon tetrachloride, ethanol, butanone, benzene, cyclohexane, acetonitrile, isopropanol, ethylene glycol dimethyl ether, propionitrile, heptane, pyridine, butanol, ethylene glycol monomethyl ether, octane, butyl acetate, chlorobenzene, ethylene glycol monoethyl ether, cyclohexanone, and dimethyl sulfoxide.

10. A method for preparing a photopolymer holographic recording medium according to any one of claims 5 to 9, characterized in that: The following steps are involved: Weigh the raw materials of each component of the photopolymer holographic recording medium into a container, and stir thoroughly until all the components are dissolved; filter using a filter membrane to obtain a mixture; apply the mixture to a substrate, and obtain the photopolymer holographic recording medium after drying.

11. The method for preparing a photopolymer holographic recording medium according to claim 10, wherein: Drying is carried out in a dark room at a humidity of 10% to 85% and a temperature of 20°C to 50°C; and / or, The photosensitivity of the photopolymer holographic recording medium is greater than 100 cm 2 / mJ.

12. 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 1 to 9.

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

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