Composition for holographic recording medium and holographic recording medium

Abstract

The invention relates to a composition for a holographic recording medium and the holographic recording medium. The composition for the holographic recording medium comprises the following components: a substrate film-forming substance, an active monomer, a photoinitiator and the like. Wherein a substrate film-forming substance mainly adopts a mechanical support as an active monomer to construct a free shuttling spatial network structure, and needs certain rigidity and heat-resistant stability, and tests show that the rigidity and heat-resistant stability of the material can be obviously improved by introducing unsaturated ring structures such as a benzene ring, a naphthalene ring and a do-not ring into the structure; therefore, a powerful spatial network structure is provided for free shuttling of the active monomers, and the display effect of the holographic recording medium is guaranteed.

Description

Technical Field

[0001] The present application relates to the technical field of holograms, and more particularly to a composition for a holographic recording medium and a holographic recording medium using the composition for a holographic recording medium. Background Art

[0002] Holographic technology refers to an optical information technology that uses the principle of optical coherence to record the amplitude and phase of light waves. It is widely used in the fields of holographic anti-counterfeiting and data storage. In this process, as the carrier of holographic recording, the holographic recording medium is particularly critical. Typical holographic recording media include: silver halide latex, dichromated gelatin, photodegradable polymers, photoconductive thermoplastic materials, photoisomerized materials, photorefractive materials (including liquid crystals), metasurface materials, photopolymers, etc.

[0003] Among them, the post-processing process of silver halide emulsion is complicated and easily produces a large amount of waste liquid to pollute the environment; dichromated gelatin, photodegradable polymers, photoconductive thermoplastic materials and photoisomerized materials have the problem of low photosensitivity and refractive index modulation; photorefractive materials usually require additional external electric fields, the equipment is complex and the safety is poor; metasurface materials are difficult to construct and the process is complicated. As a result, these media cannot produce high-performance volume holographic gratings (VHG). In contrast, photopolymers not only have the advantages of high photosensitivity, high resolution and good light transmittance, but also have excellent processability, and have gradually become the most promising recording medium in the field of volume holographic recording devices.

[0004] The ideal holographic photopolymer recording material should have high refractive index modulation, wide spectral response range, excellent photosensitivity, and low haze. In addition, in order to make the holographic recording medium have a good display effect after exposure, it must also have good stability, that is, the shrinkage performance of the medium should be small. Therefore, this patent mainly designs the material structure on the basis of improving the stability of the material, so as to achieve the effect of improving stability. Summary of the invention

[0005] The object of the present application is to provide a composition for a holographic recording medium and a holographic recording medium using the composition for a holographic recording medium, so as to improve at least part of the above-mentioned technical problems.

[0006] To achieve the above-mentioned purpose, in a first aspect, the embodiments of the present application provide a composition for a holographic recording medium, comprising: a substrate film-forming substance, an active monomer, and a photoinitiator;

[0007] The substrate film-forming substance is a compound having one functional group selected from isocyanate group, urethane group, amide group, urea group, epoxy group, and hydroxyl group, or is obtained by reacting compounds having at least two functional groups, wherein the compound having an isocyanate group includes at least 2 -NCO structures, and the compound having a hydroxyl group includes at least 3 -OH structures;

[0008] The compound having an isocyanate structure must satisfy the following general structural formula:

[0009]

[0010] Wherein, R1 is a C chain skeleton having at least one benzene ring structure, and the relative molecular mass of R1 is not greater than 1000.

[0011] As a preferred embodiment of the present application, the compound having an isocyanate structure is specifically:

[0012]

[0013] As a preferred embodiment of the present application, the refractive index of the compound having an isocyanate structure is not higher than 1.50.

[0014] As a preferred embodiment of the present application, the compound having an isocyanate structure and the compound having a hydroxyl group both have -F modified side chains.

[0015] As a preferred embodiment of the present application, the relative molecular mass of the hydroxyl compound is not more than 3000.

[0016] As a preferred embodiment of the present application, the functionality ratio between the isocyanate in the compound having an isocyanate structure and the hydroxyl in the compound having a hydroxyl group is not greater than 1:1.02.

[0017] As a preferred embodiment of the present application, the active monomer is a C4-C30 carbon chain having one or more acrylate structures, preferably an acrylate substance having an allophanate or carbamate structure in its molecular structure, and in order to expand the refractive index difference with the substrate film-forming material, the refractive index of the active monomer is ≥1.55.

[0018] As a preferred embodiment of the present application, the photoinitiator, as a sensitizing substance at a certain wavelength, has a very important influence on the photosensitivity of the material in holographic technology, which is subject to the absorption of a specific wavelength. In the present application, the photoinitiator is a compound known per se and commercially available on the market. Taking a light source with a wavelength of 520nm as an example, the photoinitiator is a combination of rose bengal or rhodamine with n-aminoglycine or ethylenediamine, or a combination of a boron-containing quaternary ammonium salt and rose bengal.

[0019] As a preferred embodiment of the present application, based on the total amount of the composition, the content of the substrate film-forming substance is 15% to 60%, the content of the active monomer is 20% to 50%, and the content of the photoinitiator is 0.01% to 1%.

[0020] In a second aspect, the embodiments of the present application further provide a holographic recording medium, which is prepared by the composition for holographic recording medium described in any one of the first aspects.

[0021] Compared with the prior art, the embodiments of the present application provide a composition for holographic recording media and a holographic recording medium, wherein the composition for holographic recording media comprises the following components: a substrate film-forming substance, an active monomer, and a photoinitiator, etc. The substrate film-forming substance mainly uses mechanical support to construct a spatial network structure for the active monomer to shuttle freely, which requires a certain rigidity and heat resistance stability. Experiments show that the introduction of unsaturated cyclic structures such as benzene rings, naphthalene rings, and naphthalene rings into the structure can significantly improve the rigidity and heat resistance stability of the material, thereby providing a strong spatial network structure for the active monomer to shuttle freely, and ensuring the display effect as a holographic recording medium. DETAILED DESCRIPTION

[0022] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application are clearly and completely described below. Obviously, the described embodiments are only embodiments of a part of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present application.

[0023] Example 1

[0024] Under the red light protection environment, 30-35% of polyether triol, 40% of polyethylene glycol o-phenylphenyl ether acrylate (abbreviated as: OPPEA) active monomer, 0.1% of rose red and 0.3% of N-phenylglycine are pre-mixed, and then 8-12% of dimethyl diphenyl diisocyanate and 0.1% of organic tin are added and mixed again after mixing evenly to obtain a clear photosensitive solution. Then, under the red light protection, a certain amount of the above-mentioned photosensitive solution is absorbed and siphoned into a glass box of a specific thickness to form a film. In the embodiment of the present application, the box thickness is 10 μm. Finally, after the siphoning is completed, the glass box is protected from light with tin foil and placed in an oven at 70°C for 1 hour.

[0025] Example 2

[0026] In a red light protection environment, 30-35% of polyether triol, 40% of polyethylene glycol o-phenylphenyl ether acrylate (OPPEA) active monomer, 0.1% of rose bengal and 0.3% of N-phenylglycine were pre-mixed, and then 8-12% of 4,4 ， -Methylenebis(phenyl isocyanate) and 0.1% of organic tin are added thereto and mixed again, and a clear photosensitive liquid is obtained by reaction. Then, under the protection of red light, a certain amount of the above-mentioned photosensitive liquid is absorbed and siphoned into a film in a glass box of a specific thickness. In the embodiment of the present application, the box thickness is 10 μm. Finally, after the siphoning is completed, the glass box is protected from light with tin foil and placed in an oven at 70°C for 1 hour.

[0027] Example 3

[0028] Under the red light protection environment, 30-35% of polyether triol, 40% of polyethylene glycol o-phenylphenyl ether acrylate (abbreviated as: OPPEA) active monomer, 0.1% of rose red and 0.3% of N-phenylglycine are pre-mixed, and then 8-12% of naphthalene-1,5-diisocyanate and 0.1% of organic tin are added and mixed again after mixing evenly to obtain a clear photosensitive solution. Then, under the red light protection, a quantitative amount of the above-mentioned photosensitive solution is absorbed and siphoned into a glass box of a specific thickness to form a film. In the embodiment of the present application, the box thickness is 10 μm. Finally, after the siphoning is completed, the glass box is protected from light with tin foil and placed in an oven at 70°C for 1 hour.

[0029] Comparative Example 1

[0030] Under the red light protection environment, 30-35% of polyether triol, 40% of OPPEA active monomer and 0.1% of rose red + 0.3% of N-phenylglycine are pre-mixed, and then 8-12% of 4,4-diisocyanate dicyclohexylmethane monomer and 0.1% of organic tin are added and mixed again to obtain a clear photosensitive liquid. Then, under the red light protection, a certain amount of the above-mentioned photosensitive liquid is absorbed and siphoned into a glass box of a specific thickness to form a film. In the embodiment of the present application, the box thickness is 10 μm. Finally, after the siphoning is completed, the glass box is protected from light with tin foil and placed in an oven at 70°C for 1 hour.

[0031] Table 1: Test results of Examples 1-3 and Comparative Examples

[0032] Serial number Diffraction efficiency Refractive index modulation Shrinkage Comparative Example 1 36％ 0.012 4.69％ Example 1 58％ 0.017 2.87％ Example 2 66％ 0.019 1.68％ Example 3 63％ 0.018 2.32％

[0033] As can be seen from Table 1, the holographic recording media in Examples 1-3 have significantly improved diffraction efficiency and shrinkage compared to the holographic recording media in the comparative example due to the limited design of the isocyanate structure. The reason is that the rigidity and heat resistance stability of the material can be significantly improved by introducing unsaturated cyclic structures such as benzene rings, naphthalene rings, and phthalic acid rings into the isocyanate structure, thereby providing a strong spatial network structure for the free shuttle of active monomers and ensuring the display effect of the holographic recording medium. In addition, the organic tin in the above embodiments is a catalyst to catalyze the film-forming substance of the substrate.

[0034] It should be noted that the composition for holographic recording medium provided in the present application may also introduce some small molecular substances with high boiling points as toughening agents, and the preferred boiling point should be greater than 200 degrees Celsius.

[0035] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A composition for a holographic recording medium, characterized in that: include: Base film-forming material, active monomer, photoinitiator; The substrate film-forming substance is a compound having one functional group selected from isocyanate group, urethane group, amide group, urea group, epoxy group, and hydroxyl group, or is obtained by reacting compounds having at least two functional groups, wherein the compound having an isocyanate group includes at least 2 -NCO structures, and the compound having a hydroxyl group includes at least 3 -OH structures; The compound having an isocyanate structure must satisfy the following general structural formula: Wherein, R1 is a C chain skeleton having at least one benzene ring structure, and the relative molecular mass of R1 is not greater than 1000.

2. The composition for holographic recording medium according to claim 1, characterized in that: The compound having an isocyanate structure is specifically:

3. The composition for holographic recording medium according to claim 1, characterized in that: The compound having an isocyanate structure has a refractive index of no more than 1.

50.

4. The composition for holographic recording medium according to claim 1, characterized in that: The compound having an isocyanate structure and the compound having a hydroxyl group both have a -F modified branched chain.

5. The composition for holographic recording medium according to claim 1, characterized in that: The relative molecular mass of the hydroxy compound is not more than 3000.

6. The composition for holographic recording medium according to claim 1, characterized in that: The functionality ratio between the isocyanate in the compound having an isocyanate structure and the hydroxyl in the compound having a hydroxyl group is not greater than 1:1.

02.

7. The composition for holographic recording medium according to claim 1, characterized in that: The active monomer is a C4-C30 carbon chain having one or more acrylate structures, and the refractive index of the active monomer is ≥1.

55.

8. The composition for holographic recording medium according to claim 1, characterized in that: The photoinitiator is a combination of rose bengal or rhodamine with n-aminoglycine or ethylenediamine, or a combination of a boron-containing quaternary ammonium salt and rose bengal.

9. The composition for holographic recording medium according to claim 1, characterized in that: Based on the total amount of the composition, the content of the substrate film-forming substance is 15% to 60%, the content of the active monomer is 20% to 50%, and the content of the photoinitiator is 0.01% to 1%.

10. A holographic recording medium, characterized in that: The holographic recording medium is prepared by the composition for holographic recording medium according to any one of claims 1 to 9.

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