JPH11161139A - Hologram recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hologram recording material which solves the problems of the degradation in the sensitivity of the hologram recording material on account of the difficult solubility of ionic dyes used for a sensitizing agent of a photoinitiator in general org. solvents to dissolve binders and monomers and the infeasibility of mixing in a suitable amt. of the sensitizing agent and flocculation and precipitation on account of the absence of compatibility in spite of mixing, is excellent in chemical stability, for example, light resistance, heat resistance and preservable stability and is high in photosensitivity and photosensitization rate. SOLUTION: The dyestuff sensitizing agent (D) capable of sensitizing the hologram recording material consisting of a thermosetting epoxy oligomer (A), a photopolymerizable compd. (B), the photoinitiator (C) and a dyestuff sensitizing agent (D) in a visible light region is ether or ester bonded into the structure of the thermosetting epoxy oligomer, by which the sensitizing agent efficiency is improved, the vaporization of the sensitizing agent is prevented and the excellent characteristics, such as the higher sensitivity, higher resolution and stable chemical stability, of the hologram recording material are exhibited.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hologram recording material used for forming a volume phase hologram, which has high sensitivity to visible light, especially argon laser light or electron beam, and further has weather resistance and storage stability. The present invention relates to a hologram recording material for providing a hologram having excellent hologram characteristics such as excellent resolution, diffraction efficiency, and transparency.

[0002]

2. Description of the Related Art Conventionally, holograms have been used for covers of books, magazines, etc., POP displays, gifts, etc. because of their excellent design and decorative effects, since holograms can reproduce a three-dimensional stereoscopic image. Also, since holograms can be said to be equivalent to information in submicron units, securities,
It is also used for forgery prevention marks such as credit cards. In particular, the volume phase hologram can modulate the phase without absorbing the light beam passing through the image by forming spatial interference fringes having different refractive indexes instead of optical absorption in the hologram recording medium. Therefore, in recent years, in addition to display applications, application to hologram optical elements (HOE) typified by head-up displays (HUD) mounted on automobiles is expected.

Incidentally, a volume phase type hologram recording material is required to be sensitive to laser light having a visible oscillation wavelength with high sensitivity and to exhibit high resolution. Further, it is required that characteristics such as diffraction efficiency, wavelength reproducibility of reproduction light, and bandwidth (half-value width of reproduction light peak) of the actually produced hologram match the intended use. Particularly, the hologram recording material for HOE has a diffraction efficiency of a spatial frequency of 5,000 to 60.
At 90 lines / mm, 90% or more, the half width (band width) of the peak of the reproduction light is preferably 20 to 30 nm, and the peak wavelength of the reproduction wavelength is preferably within 5 nm from the photographing wavelength. There is also a need for excellence.

[0004] The general principles of hologram fabrication are described in several documents and specialized books, for example, Chapter 2 of "Holographic Display" (edited by Junpei Tsujiuchi; Sangyo Tosho). According to these, a coherent two-beam, generally, one of the laser beams is irradiated to a recording object, and a photosensitive recording medium, for example, a photographic dry plate is placed at a position where total reflection light from the recording object can be received. The recording medium is irradiated directly with the other coherent light in addition to the reflected light from the object without hitting the object. The reflected light from the object is referred to as the target light, and the light that is directly applied to the medium is referred to as reference light.
Interference fringes between the reference light and the target light are recorded as image information. Next, when the produced hologram is observed under appropriate illumination, the light from the illumination light source is diffracted by the hologram so as to reproduce the wavefront of the reflected light that first arrived at the recording medium from the object during recording. As a result, an object image similar to the real image of the target object is observed three-dimensionally. A hologram formed by causing the reference light and the target light to enter the recording medium from the same direction is known as a transmission hologram. On the other hand, holograms formed by making incident from opposite sides of a recording medium are generally known as reflection holograms. The transmission hologram can be obtained by a known method as disclosed in, for example, US Pat. No. 3,506,327 and US Pat. No. 3,894,787. Further, a reflection type hologram is disclosed in, for example, US Pat.
It can be produced by a known method disclosed in Japanese Patent Application Laid-Open No. 06-2006.

A value for comparing a hologram formed as an image is refractive index modulation. This is because, when a recording medium is irradiated with two light beams so as to form the same angle with the medium and a diffraction grating is produced, the diffraction efficiency is determined by the ratio of incident light diffracted by the diffraction grating, that is, the diffraction efficiency and the thickness of the recording medium. Value. Refractive index modulation is a quantitative measure of the change in refractive index that occurs in exposed and unexposed areas of a volume hologram, i.e., where light interferes and strengthens and destructs, and is described by H. Kogelnik. Theoretical formula [B
ell. Svt. Tech. J. , 48, 2909,
(1969). ]. Generally, reflection phase holograms have higher resolution than transmission holograms, that is, recording is difficult because of the large number of interference fringes formed per mm, and it is difficult to obtain high refractive index modulation.

As a recording material for such a volume phase type hologram, a photosensitive material based on a bleached silver salt and a gelatin based dichromate has been generally used. Gelatin based dichromate photosensitive materials are the most widely used materials for recording volume phase holograms due to their high diffraction efficiency and low noise characteristics. However, this photosensitive material has a short shelf life and must be prepared each time it is produced.
In addition, since the wet development is performed, the hologram is deformed in the process of swelling and shrinking the gelatin necessary for producing the hologram. Therefore, there is also a problem that reproducibility is poor. Further, the silver salt photographic material requires complicated processing after recording, and this is not a photographic material satisfactory from the viewpoint of stability and workability. Further, all of these photosensitive materials have a problem that they are inferior in environmental resistance characteristics, for example, moisture resistance and weather resistance.

On the other hand, it has excellent environmental resistance and
A hologram recording material using poly-N-vinyl carbazole is a material having characteristics that a hologram recording material should have such as high resolution and high diffraction efficiency. For example, a hologram recording material comprising a cyclic cis-α-dicarbonyl compound as a crosslinking agent and a sensitizer (JP-A-60-45)
No. 283), a hologram recording material comprising 1,4,5,6,7,7-hexachloro-5-norbornene-anhydro-2,3-dicarboxylic acid and a dye (JP-A-60-227).
No. 280), a hologram recording material comprising 2,3-norbornanedione and thioflavin (JP-A-60-26)
0080), a hologram composed of Thioflavin T and iodoform (Japanese Patent Application Laid-Open No. 62-123489) and the like. Since these hologram recording materials also require wet development, they require complicated processing steps and have a problem of poor reproducibility. Also,
Since it is a photosensitive material mainly composed of poly-N-vinylcarbazole, it is chemically stable, has high resolution, and has excellent environmental resistance. However, poly-N-vinylcarbazole is easily crystallized to be very white and transparent. Poor reproducibility of sex,
There is also a problem that the solvent is limited. Further, further improvement in sensitivity characteristics is desired.

As a material which can be photocured with high sensitivity, a photocurable resin composition using a photoinitiator comprising a combination of 3-ketocoumarins and a diaryliodonium salt (JP-A-60-88005). A hologram recording material combining a photopolymerization initiator and polymethyl methacrylate as a supported polymer (JP-A-4-31590) has been proposed, which is chemically stable and has high resolution.
Despite having high sensitivity, because the gap is formed by wet processing, the dispersion of the peak wavelength of the reproduction wavelength and the expansion of the half width of the peak wavelength, and also, during development, the carrier polymer is slightly dissolved in the swelling solvent. However, there is a problem that development unevenness easily occurs. Furthermore, since there are many voids in the hologram, there is a problem that heat resistance and heat pressure resistance are poor.

In order to solve such a problem, photopolymerizable hologram recording materials capable of producing a hologram in one processing step without wet processing are disclosed in US Pat. No. 3,993,485 and US Pat. No. 3,658,526. ing. The former includes two types of photosensitive materials. The first example is a combination of two polymerizable unsaturated ethylenic monomers having different reactivities and refractive indices and a photopolymerization initiator, for example, cyclohexyl methacrylate, N-vinyl. This is a photosensitive resin composition comprising carbazole and benzoin methyl ether, which can be hologram-recorded by sandwiching it between two glass plates and exposing it with a two-beam optical system. Further, as a second example, a polymerizable unsaturated ethylenic monomer having a similar refractive index, an unsaturated ethylenic monomer acting as a cross-linking agent when polymerized, and a refractive index different from those of the two monomers are used. A photosensitive material which comprises a non-reactive compound and a polymerization initiator, such as butyl methacrylate, ethylene glycol dimethacrylate, 1-phenylnaphthalene, and benzoin methyl ether, and can produce a hologram in the same manner as in the first example. It is a resin composition. Whichever photosensitive resin composition is used, the polymerization of the more reactive monomer proceeds at the portion where the light intensity of the interference fringes formed by the two light fluxes increases, and a concentration gradient of the monomer occurs, resulting in a highly reactive monomer. Is diffused into a portion having high light intensity, and a monomer or a non-reactive compound having low reactivity is diffused into a portion having low light intensity.
In this way, the interference fringes are recorded with a difference in the refractive index, and a volume phase hologram is formed.

However, such a conventional photosensitive resin composition for hologram recording has the following problems. That is, in the case of the first example, even a monomer having low reactivity undergoes a certain degree of polymerization, and high refractive index modulation cannot be obtained. In the second example, 1-phenylnaphthalene, which is a non-reactive compound, exists in the system as a low molecular weight compound even after completion of the hologram, and has no storage stability. In each case, the mixture is a low-molecular-weight mixture, and has low viscosities, so that there are many problems in workability and reproducibility, such as difficulty in sandwiching between substrates and formation of a thick film.

The latter US Pat. No. 3,658,526 discloses a method for producing a stable hologram comprising a hologram recording material in which a photopolymerizable ethylenic monomer and a photopolymerization initiator are mixed in a polymer matrix. A single exposure to working radiation results in a permanent volume phase hologram. The hologram formed is fixed by subsequent full irradiation with actinic radiation. The hologram recording material disclosed here is intended to provide many advantages in terms of workability and reproducibility, but its diffraction efficiency is low. In this hologram recording material, the refractive index modulation of the completed hologram is 0.0.
It is in the range of 01 to 0.003. As a result, the reproduced image of the formed hologram has only a limited brightness. Although it is possible to provide some brightness by increasing the thickness of the hologram recording layer, this solution has resulted in the manufacturer using a large amount of hologram recording material, and has also resulted in certain media, such as in-vehicle applications. It hinders the case where the device is fixed in a laminated glass such as a head-up display. It should also be noted that the holograms formed by this generally cause a decrease in diffraction efficiency due to long-term storage.

As an improvement technique including a method for manufacturing a hologram recording material disclosed in US Pat. No. 3,658,526, US Pat. No. 4,942,112, US Pat. JP-A-2-3082 is disclosed. The basic composition is a thermoplastic resin, a polymerizable unsaturated ethylenic monomer and a photopolymerization initiator.To improve the refractive index modulation, an aromatic ring is added to either the thermoplastic resin or the polymerizable unsaturated ethylenic monomer. It is devised to have a refractive index difference by using a compound having the same. However, similar to that disclosed in U.S. Pat. No. 3,658,526, a high molecular weight resin is used as a binder matrix, which limits the diffusibility of monomers during exposure and requires a large amount of exposure. And high diffraction efficiency cannot be obtained. Further, in order to improve this point, a non-reactive plasticizer is added. However, this use causes a problem in the film strength of the formed hologram, and also causes the non-reactive plasticizer to have a hologram. Even after completion, it is present in the system as a low molecular weight compound and has no storage stability. In addition, since the carrier holding this is a thermoplastic resin, it has a drawback of poor heat resistance.

On the other hand, according to Japanese Patent Application Laid-Open No. Hei 5-107999, which is an improvement technique for the above-mentioned disadvantage, a cation polymerizable monomer and a cation polymerization initiator are blended in place of the plasticizer in the above patent. The problem caused by the non-reactive plasticizer remaining after hologram formation is solved. However, a considerable amount of light irradiation is required for fixing after hologram formation, and a low molecular weight cationic polymerizable monomer is diffused during fixing, resulting in distortion of the formed hologram and obtaining high diffraction efficiency. Can not do. Further, similarly to the prior art, since the carrier holding the carrier is a thermoplastic resin, there is a disadvantage that the heat resistance is poor. Furthermore, in a system that does not use a thermoplastic resin as a carrier for holding, many problems remain in workability and reproducibility, such as difficulty in sandwiching between substrates due to low viscosity and difficulty in forming a thick film. I have.

Further, a photosensitive resin composition for hologram recording comprising an epoxy resin, a radically polymerizable unsaturated ethylenic monomer and a photoradical polymerization agent is disclosed in Japanese Patent Laid-Open No. 5-94.
No. 014. As can be seen from the examples, two types of epoxy resins are used. However, when an ultraviolet curable epoxy resin is used, complicated work such as performing radical polymerization and cationic polymerization with light in different wavelength ranges is required. In addition, in order to adjust the diffusibility of the monomer, fine adjustment such as increasing the viscosity by pre-exposure is required, and workability and reproducibility are difficult. Further, when a thermosetting epoxy resin and a curing agent are used, the workability is extremely poor because a considerable amount of ultraviolet curing and heating time are required for curing the epoxy resin for fixing. In addition, high diffraction efficiency cannot be obtained with the improved technology disclosed herein. Thus, there is a need for improved photopolymerizable hologram recording materials for hologram recording and optical elements using the same.

Various types of photosensitive resins are currently in practical use, but cinnamate-based photosensitive resins have been developed since the oldest and are still used in the production of printed circuits and the like. It is a resist. On the other hand, acrylic oligomers and polymers are used in a wide variety of applications such as photocurable printing inks, solder resists, and dry films. In each case, the sensitivity in the unsensitized state was low, and effective sensitizers of cinnamate were 5-nitroacenaphthene and N-, respectively.
Acetyl-4-nitro-1-naphthylamine, picramide, etc., and benzoin, ketals, anthraquinones, etc. are added as acrylic photopolymerization initiators. However, in the photosensitive resin coating step and the pre-baking step (and further in the post-baking step), the low-molecular-weight sensitizer and stabilizer may ooze onto the surface of the polymer film and further sublime into the atmosphere. In the case of a solder resist or other surface coating material after the coating film is cured, an unreacted photopolymerization initiator may precipitate on the surface during use. Such a phenomenon not only reduces the sensitivity of the photosensitive resin and the reproducibility of the workability, but also leads to a deterioration in the work environment and a decrease in the reliability of parts.

In recent years, as one of the methods for solving these problems, studies have been made on polymerizing a sensitizer. Polymerization of a sensitizer is a photochemical reaction of an organic compound.
From the standpoint of simplicity of isolation and purification of the product from the reaction system, recovery and reuse of the sensitizer and improvement of the sensitizer efficiency, and in photosensitive resins, prevention of volatilization of the sensitizer, From the standpoint of higher sensitivity and higher resolution, and in applications to other polymer materials, attention has been paid to polymerization of sensitizers and their use for reasons such as improving material properties and stabilizing polymers. ing. In recent studies on polymer sensitizers, it is not limited to polymerization of simple sensitizers, but by controlling the introduction rate and designing the reaction field, it can be compared with low molecular sensitizers. Polymer sensitizers and reaction systems exhibiting excellent sensitizing effects have begun to be found.

In consideration of this point, Japanese Patent Application Laid-Open No. Hei 7-261640 discloses a hologram recording material which is further improved. According to the above patent, a hologram recording material comprising a combination of an epoxy oligomer and an ethylenic monomer which are solid at normal temperature and normal pressure and having excellent environmental resistance, particularly excellent heat resistance, is disclosed.

[0018]

However, conventionally disclosed hologram recording materials, including the above-mentioned hologram recording material, require a binder, a monomer, and an initiator system with an appropriate solvent when preparing a recording medium for obtaining a hologram. It is necessary to dissolve uniformly or to dissolve a solid component such as a binder or an initiator system with a liquid component such as a monomer without using a solvent to make the composition uniform. Binders and monomers dissolve in common organic solvents, but do not dissolve in water or alcoholic solvents. On the other hand, ionic dyes such as (thio) xanthene dyes, which are useful as sensitizers for photoinitiators, are soluble in water or alcoholic solvents, but are slightly soluble in general organic solvents in which binders and monomers are soluble. Can you solve
Since most of them cannot be dissolved at all, the sensitizer cannot be mixed in an appropriate amount, and there is a problem that the sensitivity of the obtained light-sensitive material is reduced. However, there is a problem of aggregation and precipitation due to the absence.

The present invention has been made in view of such problems, and has as its object to be improved in chemical stability, for example, light resistance, heat resistance, storage stability, and high photosensitivity. In addition, it is an object of the present invention to provide a hologram recording material having a high photosensitive speed.

[0020]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention.

That is, the first aspect of the present invention provides (A)
Glycidyl group should be at least 1
Having at least one cationically polymerizable thermosetting epoxy oligomer and (B) a radically polymerizable ethylenically unsaturated bond which is liquid at normal temperature and normal pressure and has a boiling point of 100 ° C. or higher at normal pressure A photopolymerizable compound;
(C) a photoinitiator that generates a radical species that activates radical polymerization upon exposure to actinic radiation and a Bronsted acid or Lewis acid that activates cationic polymerization; A hologram recording material comprising a dye sensitizer which can be sensitized by the method described above, wherein the dye sensitizer (D) is supported by an ether or ester bond in the structure of the thermosetting epoxy oligomer. It is a hologram recording material.

The hologram recording material according to claim 2 is
According to the first aspect of the present invention, the thermosetting epoxy oligomer (A) has an epoxy equivalent of 400 or more and is solid at normal temperature and normal pressure.

The hologram recording material according to claim 3 is
According to the invention of any one of claims 1 and 2, the thermosetting epoxy oligomer (A) is a non-aromatic thermosetting epoxy oligomer.

The hologram recording material according to claim 4 is
According to the invention of any one of claims 1 and 2, the thermosetting epoxy oligomer (A) is a bisphenol A type epoxy oligomer.

A hologram recording material according to a fifth aspect is based on any one of the first to fourth aspects, wherein the photoinitiator (C) is an aromatic onium salt, an iron arene complex or a triazine compound. I do.

The hologram recording material according to claim 6 is
According to any one of claims 1 to 4, the photoinitiator (C) is a diaryliodonium salt.

A hologram recording material according to a seventh aspect is based on any one of the first to sixth aspects, wherein the dye sensitizer (D) is a (thio) xanthene dye.

The hologram recording material according to the eighth aspect is based on any one of the first to seventh aspects, and is characterized by containing an aromatic amine (E).

[0029]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
FIG. 1 is a schematic diagram illustrating the configuration of a hologram recording medium made of the hologram recording material of the present invention, and FIG. 2 is a schematic explanatory diagram illustrating a two-beam optical system for hologram imaging.

The component (A) of the present invention is a solvent-soluble, thermopolymerizable epoxy oligomer having at least one glycidyl group in a unit structure and having at least one glycidyl group, such as bisphenol A, bisphenol AD, bisphenol B, bisphenol AF, and the like. Condensation of epichlorohydrin with various bisphenol compounds such as bisphenol S, brominated bisphenol A, hydrogenated bisphenol A, hydrogenated bisphenol AD, hydrogenated bisphenol B, hydrogenated bisphenol S, hydrogenated bisphenol AF and hydrogenated bromination Produced by reaction. Specific examples include commercially available products, such as Epicoat 1001, 1002, 1004, 1
007, 1009, 1010, 1100L (Yukaka Epoxy Co., Ltd.) and Araldite 6071, 6084, 609
7, 6099 (CIBA) and Dow 661, 664, 667
(Dow Chemical), YDB 500, 406, 408,
412 and ZX1417, 1413, ST5100, 508
0 (Toto Kasei) and EBPS-300 (Nippon Kayaku), but are not limited to these. Also, a combination of two or more of these can be used.

The component (B) of the photopolymerizable compound capable of undergoing radical polymerization used in the present invention is a compound having at least one ethylenically unsaturated bond in its structural unit.
It contains a polyfunctional vinyl monomer in addition to a functional vinyl monomer, and may be a mixture thereof. Specifically, (meth) acrylic acid, itaconic acid, maleic acid, (meth) acrylamide, diacetone acrylamide, high boiling vinyl monomers such as 2-hydroxyethyl (meth) acrylate, and further, an aliphatic polyhydroxy compound, For example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, neopentyl glycol, 1,3-propanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, 1,10-
Decanediol, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol,
Di- or poly (meth) acrylates such as mannitol, or alicyclic polyhydroxy compounds,
For example, mono- or di (meth) acrylates such as dicyclopentanol, dicyclopentenol, and tricyclodecane dimethylol are exemplified. Also,
Preferably, polyethylene glycol di (meth) acrylate or polypropylene glycol di (meth) acrylate can be used, but is not limited thereto.

The component (C) of the present invention includes photoinitiators that generate a radical species that activates radical polymerization and a Bronsted acid or Lewis acid that activates cationic polymerization when exposed to actinic radiation. Photopol. Sc
i. Technol., 2 , 283 (1989) described compounds, aromatic onium salts, iron arene complexes, trihalogenomethyl-substituted s-triazines, iodonium salts, sulfonium salts,
Examples thereof include a diazonium salt, a selenonium salt and an arsonium salt, and among them, a diaryliodonium salt is preferable. Examples of the diaryliodonium salt used in the present invention include Macromolecules, 1
0,1307 (1977). Compounds described in, for example,
Chlorides and bromides of iodonium such as diphenyliodonium, ditolyliodonium, phenyl (p-anisyl) iodonium, bis (m-nitrophenyl) iodonium, bis (p-tert-butylphenyl) iodonium and bis (p-chlorophenyl) iodonium; Alternatively, a borofluoride salt, a hexafluorophosphate salt, a hexafluoroarsenate salt, and the like can be given, but it is not limited thereto. When these photoinitiators are used as one component of the hologram recording material, they need to be sensitized with an organic dye compound.

As the dye sensitizer capable of sensitizing the photoinitiator of the component (D) of the present invention in the visible light region, (thio) xanthene dyes are particularly preferably used. Compounds. For example, Rhodamine 110,
Rhodamine 123, Rhodamine 6G, Rhodamine 11
6, rhodamine B, rhodamine 19, fluorescein,
Eosin, Erythrosin, Rose Bengal, Acridine Red 3B, Pyronin G, Rhodamine Charlach G,
C. I. Basic Red 1, Rosin 2G, Rhodamine 4G, C.I. I. Basic Violet 10, Rhodamine 120F, C.I. I. Acid Red 52, Rhodamine S, and the like, but are not limited thereto.

As the component (E) aromatic amine of the present invention, an aniline compound is particularly preferably used, and specific examples thereof include the following compounds. That is, aniline, 4-chloro-2-nitroaniline, 6-chloro-
2-cyano-4-nitroaniline, 6-bromo-2-cyano-4-nitroaniline, 5-chloro-2-phenoxyaniline, 4-amino-2-methylaniline, 2-methyl-4-nitroaniline, , 5-Diethoxyaniline, 2,4,6-trichloroaniline, 4-amino-
2,6-dichloroaniline, 2,5-dichloroaniline, 2-chloroaniline, 2-chloro-5-cyanoaniline, 2,6-dichloro-4-nitroaniline, 4-amino-2-nitroaniline, 2- Amino-4-nitroaniline, 2-nitro-4-sulfonic acid sodium aniline, 2-cyano-4-nitroaniline, 2-amino-4
-Chloroaniline, 3-chloroaniline, 2,4,5-
Trichloroaniline, 2-methoxy-5-sulfamoylaniline, 3-N, N-dimethylamino-4-methoxyaniline, 2,5-dimethoxyaniline, 2-methoxy-5-N, N-diethylsulfamoylaniline , 2
-Methoxy-5-benzylsulfonylaniline, 2,
5-diethoxy-4-nitroaniline, 2,5-dimethoxy-4-nitroaniline, 4-methoxy-2-nitroaniline, 2-methoxy-5-nitroaniline, 2-methoxy-4-nitroaniline, 2,5 -Dimethoxy-4
-Nitro-4-phenylazoaniline, 2-chloro-5
-Trifluoromethylaniline, 4-chloro-2-methylaniline, 5-chloro-2-methylaniline, 2,2
-Dimethyl-4-phenylazoaniline, 5-chloro-
2,4-dimethoxyaniline, 5-chloro-2-methoxyaniline, 3-carboxyaniline, 4-carboxyphenylhydrazine, 5-carboxy-2-chloroaniline, 5-carboxy-2-methoxyaniline, 4-benzoylamino- 2,5-diethoxyaniline, 2-methoxy-5-N-phenylcarbamoylaniline, 4-
Benzoylamino-2-methoxy-5-methylaniline, 5-carbamoyl-2-methoxyaniline, 3-chloro-2-methoxy-2-methyl-5-N-phenylcarbamoylaniline, 2-chloro-2-methoxy-5 −
N-phenylcarbamoylaniline, 4-acetylamino-2-carboxyaniline, 4-N-phenylcarbamoylaniline, 5-carbamoyl-2-chloroaniline, 4-carbamoylaniline, 5-carbamoyl-2
-Methylaniline, 4-benzoylamino-2,5-dimethoxyaniline, 4-methoxyaniline, 4-N, N
-Diethyl-2,5-dimethoxyaniline, 4-N, N
-Diethyl-2-methoxyaniline, 4-methylaniline, 4-N, N-dibenzoyl-3,5-dichloroaniline, 4-N, N-dimethylaniline, 4-nitroaniline, 4-N, N-diethylaniline , 4-methoxy-
2,5-diethoxy-4-benzoylaminoaniline,
4-N-benzyl-N-methyl-2,5-dimethoxyaniline, 4-methyl-2,5-diethoxy-phenylthioaniline, 4-methoxy-2,5-diethoxy-phenylthioaniline, 4-methoxy-2 , 5-Dimethoxy-phenylaniline, 2,5-dimethoxyaniline, 4
-N, N-dipropylaniline, 4-N-hydroxyethyl-N-ethylaniline, 4-N, N-diethyl-3
-Chloroaniline, 4-N-benzyl-N-methyl-
Examples include compounds such as 2,5-dimethoxyaniline, but are not limited thereto.

According to the present invention, by binding the dye sensitizer to the polymer, the compatibility of the sensitizing dye is increased, and further higher sensitivity can be achieved. Hereinafter, a method for producing a polymer sensitizer into which a photosensitizing residue has been introduced will be described.
First, in the first method, a carboxylate group of a (thio) xanthene derivative is reacted with a hydroxyl group on a main chain of a thermosetting epoxy oligomer, and a sensitizing dye is introduced into an epoxy polymer main chain using an ester bond. Things.

The second method involves reacting a hydroxy group of a (thio) xanthene derivative with a hydroxyl group on the main chain of a thermosetting epoxy oligomer, and introducing a sensitizing dye into the epoxy oligomer using an ether bond. is there.

Further, the hologram recording material of the present invention includes:
If necessary, additives such as a thermal polymerization inhibitor, a chain transfer agent and an antioxidant can be added.

As described above, these components are appropriately selected, and the photosensitive solution obtained by mixing the components at an arbitrary ratio is coated on a glass plate or the like by using a known coating means such as a spin coater, a roll coater, or a bar coater. A film is formed on a substrate 2, such as a polycarbonate plate, a polymethyl methacrylate plate, or a polyester film, to produce a hologram recording medium 1. At this time, the protective layer 4 is formed on the photosensitive layer 3 as an oxygen blocking film.
May be provided. As the protective layer 4, for example, a material equivalent to the substrate 2, or a film or glass of polyolefin, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate, or the like can be used. When the photosensitive liquid is applied, it may be diluted with an appropriate solvent as necessary, but in that case, drying is required after application on the substrate.

FIG. 2 is a schematic view for explaining a two-beam optical system for reflection type hologram photographing. A laser beam 6 oscillated from a laser 5 passes through a mirror 7, a beam splitter 8, a spatial filter 9, and a lens 10. The hologram recording medium 1 is irradiated through the hologram recording medium 1. Although not described in detail or shown in the drawings, the present invention can be similarly applied to the production of a transmission hologram, whereby a transmission hologram having excellent hologram characteristics can be obtained.

As a light source suitable for the hologram recording material of the present invention, a helium-cadmium laser, an argon laser, a krypton laser, a helium-neon laser or the like can be used, but is not limited thereto.

As described above, in the hologram recording using the hologram recording material of the present invention, the radically polymerizable photopolymerizable compound (B), photoinitiator (C) and dye sensitizer (D) are solvent-soluble and cationically polymerizable. Irradiation of the recording material with laser interference light causes the photoinitiator (C) to be uniformly distributed in the thermosetting epoxy oligomer (A). ) Simultaneously generates radical species and Brnsted acid or Lewis acid which activate radical polymerization and cationic polymerization by the action of the dye sensitizer (D). The radical species generated here causes a difference in the concentration as the photopolymerizable compound (B) is polymerized and polymerized.
The photopolymerizable compound (B) diffuses and moves from the surroundings. That is, the monomer concentration is high in a part of the laser irradiation part where the light interference action is strong, and is low in a part of the laser irradiation part where the light interference action is weak. As a result, a difference in refractive index occurs between the two portions, and it is presumed that a latent image of the hologram is recorded. Further, by heating after hologram exposure, the remaining monomers are fixed by diffusion and polymerization, and are around interference fringes formed by polymerization of the photopolymerizable compound (B) by a strong acid generated simultaneously with radical species. It is presumed that the epoxy oligomer, which is a support, has a crosslinked structure due to cationic polymerization and the refractive index is increased, thereby enhancing the refractive index modulation. The crosslinking also improves weather resistance. Further, the hologram recording material of the present invention, compared with the conventional hologram recording material,
Since it has high sensitivity and excellent reproducibility of hologram characteristics, and also has excellent environmental resistance characteristics, it can be applied to hologram optical elements.

[0042]

Hereinafter, the present invention will be described in more detail with reference to specific examples. <Example 1> Thermosetting epoxy oligomer (bisphenol S type, trade name "EBPS300" manufactured by Nippon Kayaku Co., Ltd.)
50 g of a xanthene dye (Rose Bengal, manufactured by Tokyo Chemical Industry Co., Ltd.) (10 g) was dissolved in dimethylformamide (100 g), 1 g of p-toluenesulfonic acid was added as an acid catalyst, and the mixture was reacted at 60 ° C. for 8 hours using a water bath. After cooling, the target polymer was reprecipitated in ethanol, and this was repeated several times for purification. After washing and vacuum drying at 50 ° C., 45 g of the colored target polymer were obtained.

A photosensitive solution was prepared by mixing and dissolving 100 parts by weight of this polymer, 50 parts by weight of triethylene glycol diacrylate and 10 parts by weight of diphenyliodonium hexafluorophosphate in 100 parts by weight of 2-butanone. This photosensitive solution was applied to a glass substrate using an applicator so as to have a dry film thickness of about 15 μm, and dried to form a photosensitive layer. Thereafter, the photosensitive layer was covered with a polyvinyl alcohol (PVA) film to produce a hologram recording medium.

The hologram recording medium was exposed using a two-beam optical system for hologram photography shown in FIG. 2 using an argon laser (514.5 nm) as a light source to form a hologram image, and then heated at 100 ° C. for 30 minutes. Was done.

The diffraction efficiency of the obtained hologram was measured with a spectrophotometer manufactured by JASCO Corporation. In this spectrophotometer, a photomultimeter having a slit having a width of 3 mm can be installed on a circumference having a radius of 20 cm around a sample. The measurement conditions were such that monochromatic light having a width of 0.3 mm was incident on the sample at an angle of 45 degrees, and diffracted light from the sample was detected. The ratio between the largest value other than the specular reflection light and the case where the incident light was directly received without placing the sample was defined as the diffraction efficiency.
Table 1 shows the evaluation results.

<Example 2-5> Eosin B, erythrosin B, rhodamine B and rhodamine S were used in place of rose bengal, except that a dye was introduced into an epoxy oligomer in the same manner as in Example 1 to produce a hologram. And the diffraction efficiency was measured. Table 1 shows the evaluation results.

Comparative Example 100 parts by weight of a thermosetting epoxy oligomer (bisphenol S type, trade name "EBPS300" manufactured by Nippon Kayaku Co., Ltd.), 50 parts by weight of triethylene glycol diacrylate, and 10 parts by weight of diphenyliodonium hexafluorophosphate A solution obtained by mixing and dissolving 5 parts by weight of Rose Bengal with 100 parts by weight of 2-butanone was used as a photosensitive solution. This photosensitive liquid was applied to a glass substrate using an applicator so that the thickness became about 15 μm, and a photosensitive layer was formed. However, when heated and dried, rose bengal was crystallized, and no good hologram was obtained. . Table 1 shows the results.

[0048]

[Table 1]

<Example 6-10> Instead of the thermosetting epoxy oligomer of Example 1-5 (trade name “EBPS300” manufactured by Nippon Kayaku Co., Ltd.), a bisphenol A type thermosetting epoxy oligomer (trade name “Epicoat”) was used. 1007 "
Except for using Yuka Shell Epoxy Co., Ltd., an epoxy oligomer carrying various dyes was prepared in the same manner as in Examples 1 to 5 and a hologram was prepared and the diffraction efficiency was measured as in Example 1-5. . Table 2 shows the evaluation results.

[0050]

[Table 2]

<Examples 11-14> As aromatic amines, aniline, N, N-diethylaniline, 2,4,6
A hologram was prepared by preparing a photosensitive solution in the same manner as in Example 8, except that 5 parts by weight of -N, N-pentamethylaniline or 4-nitroaniline was added. Table 3 shows the results.

[0052]

[Table 3]

The hologram of Example 1-14 was heated at 25 ° C.
No reduction in diffraction efficiency was observed even when left in an environment of 0% RH for 180 days and at 150 ° C. for 10 hours.

[0054]

According to the present invention, (A) a thermosetting epoxy oligomer which is soluble in a solvent and has at least one glycidyl group in a unit structure and can be cationically polymerized; and (B) a liquid which is liquid at normal temperature and normal pressure and has a boiling point at normal pressure An aliphatic monomer having at least one radically polymerizable ethylenically unsaturated bond having a temperature of 100 ° C. or higher, (C) a radical species that activates radical polymerization when exposed to actinic radiation, and a cationic polymerization. In a hologram recording material comprising a photoinitiator that generates a Bronsted acid or a Lewis acid to be reacted and (D) a dye sensitizer capable of sensitizing the photoinitiator in the visible light region, the photoinitiator is changed to the visible light region. The dye sensitizer (D), which can be sensitized by the above, is supported by an ether or ester bond in the structure of the thermosetting epoxy oligomer, so that the effect of the sensitizer is improved. Hologram recording material that exhibits excellent characteristics such as improved sensitization, prevention of volatilization of the sensitizer, higher sensitivity and higher resolution of the hologram recording material, and chemical stabilization, and has excellent weather resistance and storage stability using this material. , And resolution,
A hologram recording medium capable of producing a hologram having good hologram characteristic values such as diffraction efficiency and transparency can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of a hologram recording medium made of a hologram recording material of the present invention.

FIG. 2 is a schematic diagram illustrating a two-beam optical system for hologram imaging.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hologram recording medium 2 Substrate 3 Photosensitive layer 4 Protective layer 5 Laser 6 Laser beam 7 Mirror 8 Beam splitter 9 Spatial filter 10 Lens 11 Lens

Claims (8)

[Claims] (A) a cationically polymerizable thermosetting epoxy oligomer having at least one glycidyl group in a unit structure, which is soluble in a solvent, and (B) a liquid at normal temperature and pressure and a boiling point at normal pressure. A photopolymerizable compound having at least one radically polymerizable ethylenically unsaturated bond at a temperature of 100 ° C. or higher, and (C) a radical species that activates radical polymerization upon exposure to actinic radiation and activates cationic polymerization. A hologram recording material comprising a photoinitiator generating a Bronsted acid or a Lewis acid to be converted and (D) a dye sensitizer capable of sensitizing the photoinitiator in the visible light region, wherein a dye sensitizer (D ) Is a hologram recording material characterized in that the hologram recording material is supported by an ether or ester bond in the structure of the thermosetting epoxy oligomer. 2. The thermosetting epoxy oligomer (A)
The hologram recording material according to claim 1, wherein the hologram recording material is a solid having an epoxy equivalent of 400 or more and a normal temperature and normal pressure. 3. The hologram recording material according to claim 1, wherein the thermosetting epoxy oligomer (A) is a non-aromatic thermosetting epoxy oligomer. 4. The hologram recording material according to claim 1, wherein the thermosetting epoxy oligomer (A) is a bisphenol A type epoxy oligomer. 5. The photoinitiator (C) is an aromatic onium salt,
The hologram recording material according to any one of claims 1 to 4, wherein the hologram recording material is an iron arene complex or a triazine compound. 6. The hologram recording material according to claim 1, wherein said photoinitiator (C) is a diaryliodonium salt. 7. The hologram recording material according to claim 1, wherein the dye sensitizer (D) is a (thio) xanthene dye. 8. The hologram recording material according to claim 1, further comprising an aromatic amine (E).