JP2013050714A - Composition for hologram recording medium and hologram recording medium using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for a hologram recording medium which is excellent in recording characteristics, has little change in recording characteristics due to storage, and is excellent in storage stability, and to provide a hologram recording medium using the same.SOLUTION: A composition for a hologram recording medium is obtained by using: compound having an isocyanate group; compound having an isocyanate-reactive functional group; a polymerizable monomer; a photopolymerization initiator; and a rare earth-based catalyst.

Description

  The present invention relates to a composition for a hologram recording medium and a hologram recording medium using the same.

2. Description of the Related Art In recent years, a hologram type optical recording medium that records information as a hologram by changing the refractive index of the recording layer according to the light intensity distribution due to the interference of light toward further increase in capacity and density of the optical recording medium. Has been developed.
Among them, a hologram whose film thickness is sufficiently thick with respect to the interference fringe interval (usually having a film thickness of about 5 times the interference fringe interval or about 1 μm or more) is called a volume hologram. In addition, since the one where a film thickness is larger can perform recording in the film thickness direction, recording at a high density is possible. As an example of a known volume hologram recording material, there is a write-once type that does not require wet treatment or bleaching treatment, and its composition is generally a resin matrix in which a photoactive compound is compatible. For example, there is a photopolymer system in which a resin matrix is combined with a monomer capable of radical polymerization or cationic polymerization as a photoactive compound (see, for example, Patent Documents 1 and 2).

  At the time of recording information in hologram recording, when object light and reference light are irradiated, interference fringes composed of a bright part and a dark part are formed on the recording layer. For example, when the photoactive compound is a radical polymerizable compound, in the bright part, the photopolymerization initiator absorbs light, becomes a radical active species, and polymerization of the radical polymerizable compound occurs. As radical polymerization proceeds, a concentration gradient of the radical polymerizable compound is produced in the light and dark portions. This concentration gradient causes the radical polymerizable compound to diffuse from the dark part to the bright part, and the bright part and the dark part are composed of different chemical species and have different refractive indexes. The hologram recording medium holds this refractive index difference as information.

  The photopolymer method is a practical and promising method that can achieve both high diffraction efficiency and dry processing, but has high sensitivity, sufficient diffraction efficiency, and high S / N ratio for recording, and achieves high multiplicity. A composition is required, and a hologram recording medium having excellent stability and reliability is desired. In order to achieve these, various studies have been made on the composition of the hologram recording composition and the method of producing the hologram recording medium.

For example, in Patent Document 3, by optimizing the chain length and structure in the three-dimensional crosslinked matrix (resin matrix) structure, without sacrificing the compatibility of the matrix polymer and the writing monomer (photoactive compound), It is described that it enables a better contrast ratio and improved brightness of the hologram.
Here, when a polyurethane resin or the like is employed as the resin matrix, it is known that a tin (Sn) -based curing catalyst such as dibutyltin dilaurate is used to promote the formation of the matrix polymer (for example, (See Patent Document 1 and Patent Document 3).

JP 11-352303 A JP 2005-43862 A JP 2010-84147 A

  However, in the hologram recording medium described in the above cited reference 3, since a sensitizing dye having an absorption maximum is added near the recording wavelength, a sufficiently thick hologram recording medium has a low transmittance with respect to the recording wavelength. Thus, there is a problem that sufficient diffraction efficiency cannot be obtained with respect to the thickness. Further, the hologram recording medium has a problem that the storage stability is not sufficient.

Further, according to the study by the present inventors, when a tin (Sn) -based curing catalyst is used as the matrix curing catalyst as in Patent Document 1 and Patent Document 3, the hologram recording medium is stored during storage of the hologram recording medium. It was found that the recording characteristics of the recording medium deteriorated and the storage stability (shelf life) decreased.
In view of the above, an object of the present invention is to provide a composition for a hologram recording medium that has excellent recording characteristics, little change in recording characteristics due to storage, and excellent storage stability, and a hologram recording medium using the same. .

As a result of intensive studies by the present inventors, the use of a rare earth catalyst such as a lanthanum (La) catalyst or praseodymium (Pr) catalyst as a curing catalyst provides excellent recording characteristics and changes in recording characteristics due to storage. It has been found that a composition for a holographic recording medium can be obtained in which the turbidity does not occur when the holographic recording medium is used.
The gist of the present invention resides in a hologram recording medium composition comprising an isocyanate group-containing compound, an isocyanate-reactive functional group-containing compound, a polymerizable monomer, a photopolymerization initiator, and a rare earth catalyst. .

The rare earth catalyst is preferably a lanthanoid catalyst, and the lanthanoid catalyst is preferably a lanthanum catalyst and / or a praseodymium catalyst. The polymerizable monomer is preferably a radical polymerizable monomer.
Another gist of the present invention resides in a hologram recording medium using the above-described composition for a hologram recording medium in a recording layer.

  According to the present invention, the storage stability of the recording layer using the hologram recording medium composition can be made excellent by using the novel catalyst of the present invention.

FIG. 4 is a diagram showing M / # residual ratio and sensitivity residual ratio in the storage stability test of Example 1, Example 2, and Comparative Example 1. In Example 1, Example 2, and Comparative Example 1, it is a schematic diagram which shows the outline | summary of the structure of the apparatus used for the hologram recording, (a) A figure shows the whole apparatus, (b) A figure is an LED unit. The figure which shows the surface and (c) figure is a figure which shows the arrangement | sequence of LED.

The items and methods exemplified below are examples (representative examples) of embodiments of the present invention, and the present invention is not specified in these contents unless departing from the gist thereof.
1. Composition for hologram recording medium Composition for hologram recording medium of the present invention,
(1) Compound having an isocyanate group (hereinafter sometimes referred to as “component (1)”),
(2) a compound having an isocyanate-reactive functional group (hereinafter sometimes referred to as “component (2)”),
(3) a polymerizable monomer (hereinafter sometimes referred to as “component (3)”),
(4) Photopolymerization initiator (hereinafter sometimes referred to as “component (4)”),
(5) A rare earth catalyst (hereinafter sometimes referred to as “component (5)”) is contained.

Each will be described below.
1-1. Compound having an isocyanate group The compound having an isocyanate group reacts with a compound having an isocyanate-reactive functional group (component (2)) in the presence of a curing catalyst (component (5)) to be described later to constitute a resin matrix. .

The ratio of the isocyanate group in the molecule of the compound having an isocyanate group is preferably 50% by mass or less, more preferably 47% by mass or less, and further preferably 45% by mass or less. The lower limit is usually 0.1% by mass, preferably 1% by mass. When the ratio of the isocyanate group is larger than the above upper limit, turbidity is likely to occur when the hologram recording medium is used, and optical uniformity may be disturbed. On the other hand, when the ratio is low, the hardness of the resin matrix and the glass transition temperature become low, and recording may become unstable or disappear. The ratio of the isocyanate group in this invention shows the ratio of the isocyanate group in the whole compound which has an isocyanate group to be used.
The ratio of the isocyanate group in the compound having an isocyanate group can be obtained from the following formula.

42 (molecular weight of isocyanate group) × number of isocyanate groups / molecular weight of compound having isocyanate groups × 100
There is no restriction | limiting in particular in the kind of compound which has an isocyanate group, For example, it may have an aromatic, araliphatic, aliphatic, or alicyclic frame | skeleton. Moreover, the compound which has an isocyanate group may have one isocyanate group in a molecule | numerator, and may have two or more, but it is preferable to have two or more. A compound having two or more isocyanate groups in the molecule and a compound having three or more isocyanate-reactive functional groups in the molecule, or a compound having three or more isocyanate groups in the molecule and two or more in the molecule According to the three-dimensional cross-linked matrix obtained from a compound having an isocyanate-reactive functional group, a recording layer having excellent record retention can be obtained.

  Examples of the compound having an isocyanate group include isocyanate, butyl isocyanate, octyl isocyanate, butyl diisocyanate, hexyl diisocyanate (HMDI), isophorodiisocyanate (IPDI), 1,8-diisocyanato-4- (isocyanato). Methyl) octane, 2,2,4- and / or 2,4,4-trimethylhexamethylene diisocyanate, isomeric bis (4,4'-isocyanatocyclohexyl) methane and mixtures thereof having any desired isomeric content , Isocyanatomethyl-1,8-octane diisocyanate, 1,4-cyclohexylene diisocyanate, isomer cyclohexane dimethylene diisocyanate, 1,4-phenylene diisocyanate, 2,4- and / or 2,6-toluene diisocyanate , 1,5 Nafure Ji diisocyanate, 2,4'- or 4,4'-diphenylmethane diisocyanate and / or triphenylmethane 4,4 ', 4' '- such as triisocyanate.

It is also possible to use an isocyanate derivative having a urethane, urea, carbodiimied, acrylic urea, isocyanurate, allophanate, biuret, oxadiazinetrione, uretdione and / or iminooxadiazinedione structure. Any of these may be used alone, or two or more of these may be used in any combination and ratio.
Of these, aliphatic ones are preferred because they are difficult to color.

1-2. Compound having an isocyanate-reactive functional group The compound having an isocyanate-reactive functional group in the present invention is a compound having an active hydrogen (isocyanate-reactive functional group) involved in a chain extension reaction with a compound having an isocyanate group. is there. Examples of the isocyanate-reactive functional group include a hydroxyl group, an amino group, and a mercapto group. The compound having an isocyanate-reactive functional group may have one isocyanate-reactive group in the molecule or may have two or more, but preferably has two or more. In addition, when it has two or more isocyanate-reactive functional groups, the number of isocyanate-reactive functional groups contained in one molecule may be one or more.

  As described above, a compound having two or more isocyanate groups and a compound having three or more isocyanate-reactive functional groups, or a compound having three or more isocyanate groups and two or more isocyanate-reactive functional groups According to the three-dimensional cross-linked matrix obtained from the compound, a recording layer having excellent record retention can be obtained.

-Compound having a hydroxyl group The compound having a hydroxyl group may be one having one or more hydroxyl groups in one molecule, but one having two or more hydroxyl groups is preferable. Examples thereof include glycols such as ethylene glycol, triethylene glycol, diethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, and neopentyl glycol; diols such as butanediol, pentanediol, hexanediol, heptanediol, and tetramethylene glycol; Bisphenols, or compounds obtained by modifying these polyfunctional alcohols with polyethyleneoxy chain or polypropyleneoxy chain; these polyfunctional alcohols such as triols such as glycerin, trimethylolpropane, butanetriol, pentanetriol, hexanetriol, decanetriol, etc. Compound modified with polyethyleneoxy chain or polypropyleneoxy chain; polyfunctional polyoxybutylene; Caprolactone; polyfunctional polyesters, polyfunctional polycarbonate; and polyfunctional polypropylene glycol. Any of these may be used alone, or two or more of these may be used in any combination and ratio.

  The average molecular weight of the compound having a hydroxyl group is usually 50 or more in terms of number average molecular weight, preferably 100 or more, more preferably 150 or more. Moreover, it is 50000 or less normally, it is 10,000 or less, More preferably, it is 5000 or less. If it is less than the lower limit, the crosslink density increases, so that the hardness of the resin matrix becomes too high, and the recording speed may decrease. On the other hand, if the value is larger than the upper limit, the compatibility with other components may be lowered, or the crosslinking density may be lowered, so that the hardness of the resin matrix becomes too low and the recorded content may be lost.

-Compound having an amino group The compound having an amino group may be any compound having at least one amino group in one molecule, but preferably has two or more amino groups. Examples thereof include aliphatic amines such as ethylenediamine, diethylenetriamine, triethylenetetramine, and hexamethylenediamine; alicyclic amines such as isophoronediamine, menthanediamine, and 4,4′-diaminodicyclohexylmethane; m-xylylenediamine, diamino Aromatic amines such as diphenylmethane and m-phenylenediamine; Any of these may be used alone, or two or more of these may be used in any combination and ratio.

The average molecular weight of the compound having an amino group is usually 50 or more in terms of number average molecular weight, preferably 100 or more, more preferably 150 or more. Moreover, it is 50000 or less normally, it is 10,000 or less, More preferably, it is 5000 or less. If it is less than the lower limit, the crosslink density increases, so that the hardness of the resin matrix becomes too high, and the recording speed may decrease. On the other hand, if the value is larger than the upper limit, the compatibility with other components may be lowered, or the crosslinking density may be lowered, so that the hardness of the resin matrix becomes too low and the recorded content may be lost.

Compound having a mercapto group The compound having a mercapto group may be any compound having one or more mercapto groups in one molecule, but preferably has two or more mercapto groups. Examples thereof include 1,3-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,2-benzenedithiol, 1,3-benzenedithiol, 1,4-benzenedithiol, 1,10 -Decanedithiol, 1,2-ethanedithiol, 1,6-hexanedithiol, 1,9-nonanedithiol, pentaerythritol tetrakis (3-mercaptopropionate), pentaerythritol tetrakis (2-mercaptoacetate), pentaerythritol tetrakis (3-mercaptobutyrate), trimethylolpropane tris (3-mercaptopropionate), dipentaerythritol hexakis (3-mercaptopropionate), 1,4-bis (3-mercaptobutyryloxy) butane, etc. Is mentioned. Any of these may be used alone, or two or more of these may be used in any combination and ratio.

  The average molecular weight of the compound having a mercapto group is usually 50 or more in terms of number average molecular weight, preferably 100 or more, more preferably 150 or more. Moreover, it is 50000 or less normally, it is 10,000 or less, More preferably, it is 5000 or less. If it is less than the lower limit, the crosslink density increases, so that the hardness of the resin matrix becomes too high, and the recording speed may decrease. On the other hand, if the value is larger than the upper limit, the compatibility with other components may be lowered, or the crosslinking density may be lowered, so that the hardness of the resin matrix becomes too low and the recorded content may be lost.

1-3. Polymerizable monomer The polymerizable monomer means a compound that can be polymerized by a photopolymerization initiator described later. The kind of the polymerizable monomer used in the composition for a hologram recording medium of the present invention is not particularly limited, and can be appropriately selected from known compounds. Examples of the polymerizable monomer include a cation polymerizable monomer, an anion polymerizable monomer, and a radical polymerizable monomer. Any of these may be used, or two or more of these may be used in combination. However, it is preferable to use a radically polymerizable monomer because the compound having an isocyanate group and the compound having an isocyanate-reactive functional group are unlikely to inhibit the reaction forming the matrix.

・ Cationically polymerizable monomers Examples of cationically polymerizable monomers include epoxy compounds, oxetane compounds, oxolane compounds, cyclic acetal compounds, cyclic lactone compounds, thiirane compounds, thietane compounds, vinyl ether compounds, spiro orthoester compounds, and ethylenically unsaturated bonds. Examples thereof include a compound, a cyclic ether compound, a cyclic thioether compound, and a vinyl compound. Any one of the above cationic polymerizable monomers may be used alone, or two or more of them may be used in any combination and ratio.

Anionic polymerizable monomer Examples of the anionic polymerizable monomer include hydrocarbon monomers and polar monomers.
Examples of the hydrocarbon monomer include styrene, α-methylstyrene, butadiene, isoprene, vinyl pyridine, vinyl anthracene, and derivatives thereof.

Examples of polar monomers include methacrylic acid esters, acrylic acid esters, vinyl ketones, isopropenyl ketones, and other polar monomers.
Any one of the above-exemplified anionic polymerizable monomers may be used alone, or two or more thereof may be used in any combination and ratio.

-Radical polymerizable monomer Examples of the radical polymerizable monomer include compounds having a (meth) acryloyl group, (meth) acrylamides, vinyl esters, vinyl compounds, styrenes, spiro ring-containing compounds, and the like. Any one of the radically polymerizable monomers exemplified above may be used alone, or two or more thereof may be used in any combination and ratio. In this specification, a general term for methacryl and acryl is referred to as (meth) acryl.
Among these, a compound having a (meth) acryloyl group is more preferable from the viewpoint of steric hindrance during radical polymerization.

-Molecular weight of polymerizable monomer The polymerizable monomer used in the composition for a hologram recording medium of the present invention usually has a molecular weight of 80 or more, preferably 150 or more, more preferably 300 or more. Moreover, it is 3000 or less normally, Preferably it is 2500 or less, More preferably, it is 2000 or less. If the molecular weight is too small, there is a possibility that the shrinkage rate accompanying the polymerization of light irradiation at the time of hologram information recording becomes large. On the other hand, if the molecular weight is too large, the mobility of the polymerizable monomer in the recording layer using the composition for a hologram recording medium is low, diffusion becomes difficult to occur, and sufficient diffraction efficiency may not be obtained.

-Refractive index of polymerizable monomer The polymerizable monomer has a refractive index of usually 1.50 or more, preferably 1.52 or more, more preferably 1.55 or more at the wavelength of light irradiated to the hologram recording medium (recording wavelength, etc.). Usually, it is 1.80 or less, preferably 1.78 or less. If the refractive index is too small, the diffraction efficiency may not be sufficient and the multiplicity may not be sufficient. On the other hand, if the refractive index is excessively large, the difference in refractive index from the matrix resin becomes too large and scattering increases, resulting in a decrease in transmittance, and more energy is required for recording and reproduction. Although the refractive index shows a large value when evaluated at a short wavelength, a sample showing a relatively large refractive index at a short wavelength shows a relatively large refractive index even at a long wavelength, and the relationship is not reversed. . Therefore, it is possible to evaluate the refractive index at a wavelength other than the recording wavelength and predict the refractive index at the recording wavelength.

As the polymerizable monomer having a high refractive index, a compound having a halogen atom (iodine, chlorine, bromine, etc.) or a compound having a hetero atom (nitrogen, sulfur, oxygen, etc.) in the molecule is preferable. Among them, those having a heterocyclic structure are more preferable.
These compounds preferably have 2 or less heteroatoms in the heterocyclic structure contained in the molecule in order to ensure solubility in a solvent or a matrix. When the number is three or more, the solubility is lowered, and there is a possibility that a uniform recording layer cannot be obtained. In addition, when the structure regularity of the heterocycle in the molecule is high, coloring or dissolution decrease due to stacking may occur. Therefore, a heteroaryl group in which two or more rings are condensed is more preferable.

  Examples of preferable polymerizable monomers include compounds represented by the following (formula a) described in JP 2010-018606 A.

(In (formula a), A is a ring optionally having a substituent,
Ar is an optionally substituted (hetero) aryl group in which two or more rings are condensed, R ¹ is hydrogen or a methyl group,
n is an integer of 1 to 7,
When n is 2 or more, the plurality of Ars may be the same or different.
However, when A is an aromatic heterocycle, and Ar is a heteroaryl group in which two or more rings may have a substituent, each of A and Ar are linked. In the structure, the partial structure in each structure of A and Ar that are directly connected to each other does not contain a hetero atom. )

  Examples of the compound represented by the above (formula a) include 2- (1-thianthrenyl) -1-phenyl (meth) acrylate, 2- (2-benzothiophenyl) -1-phenyl (meth) acrylate, 2 -(4-dibenzofuranyl) -1-phenyl (meth) acrylate, 2- (4-dibenzothiophenyl) -1-phenyl (meth) acrylate, 3- (3-benzothiophenyl) -1-phenyl (meth) ) Acrylate, 3- (4-dibenzofuranyl) -1-phenyl (meth) acrylate, 3- (4-dibenzothiophenyl) -1-phenyl (meth) acrylate, 4- (1-thianthrenyl) -1-phenyl (Meth) acrylate, 4- (4-dibenzothiophenyl) -1-phenyl (meth) acrylate, 2,4-bis (1-thianthrenyl) -1-phenyl (meth) acrylate, 2,4-bis (2-dibenzothiophenyl) -1-phenyl (meth) acrylate, 2,4-bis (3-benzothiophenyl) -1-phenyl (meth) acrylate 2,4-bis (4-dibenzofuranyl) -1-phenyl (meth) acrylate, 2,4-bis (4-dibenzothiophenyl) -1-phenyl (meth) acrylate, 4-methyl-2,6 -Bis (1-thianthrenyl) -1-phenyl (meth) acrylate, 4-methyl-2,6-bis (2-benzothiophenyl) -1-phenyl (meth) acrylate, 4-methyl-2,6-bis (3-Benzothiophenyl) -1-phenyl (meth) acrylate, 4-methyl-2,6-bis (4-dibenzofuranyl) -1-phenyl (meth) acryl Over DOO, 4-methyl-2,6-bis (4-dibenzothiophenyl) -1-phenyl (meth) acrylate.

-Molar Absorption Coefficient of Polymerizable Monomer The polymerizable monomer preferably has a molar absorption coefficient of 100 L · mol ⁻¹ · cm ⁻¹ or less at the hologram recording wavelength. When the molar extinction coefficient is larger than 100 L · mol ⁻¹ · cm ⁻¹ , the transmittance of the medium is lowered, and there is a possibility that sufficient diffraction efficiency cannot be obtained with respect to the thickness.

1-4. Photopolymerization initiator The photopolymerization initiator refers to a substance that generates a cation, anion, or radical that undergoes a chemical reaction by light, and contributes to the polymerization of the above-described polymerizable monomer. There is no restriction | limiting in particular in the kind of photoinitiator, According to the kind etc. of polymerizable monomer, it can select suitably.
In the present invention, at least one oxime ester photopolymerization initiator and / or phosphine oxide photopolymerization initiator is used as the photopolymerization initiator.

  It is preferable to use 0.003% by mass or more of the oxime ester photopolymerization initiator and / or phosphine oxide photopolymerization initiator with respect to the total amount of the photopolymerization initiator, more preferably 0.03% by mass or more. Preferably it is 0.05 mass% or more. By setting it to the lower limit value or more, the effect of the present invention can be easily obtained.

-Oxime ester photopolymerization initiator The above oxime ester photopolymerization initiator only needs to have -C = N-O- as part of its structure. Compounds represented by formula d) or (formula f) are preferred.

(In the formula (d), X is a single bond; an alkylene group having 1 to 20 carbon atoms which may have a substituent, an alkenylene group which may have a substituent — (CH═CH) _n —, a substituent. A divalent group selected from the group consisting of an alkynylene group — (C≡C) _n —, and a combination thereof (where n represents an integer of 1 to 5).

R ² represents a monovalent organic group containing an aromatic ring and / or a heteroaromatic ring, and R ³ may have a substituent, each having 1 to 12 carbon atoms, an alkylthio group having 2 to 12 carbon atoms. Alkoxycarbonyl group, alkenyloxycarbonyl group having 3 to 12 carbon atoms, alkynyloxycarbonyl group having 3 to 12 carbon atoms, aryloxycarbonyl group having 7 to 12 carbon atoms, heteroaryloxycarbonyl group having 3 to 12 carbon atoms, carbon An alkylthiocarbonyl group having 2 to 12 carbon atoms, an alkenylthiocarbonyl group having 3 to 12 carbon atoms, an alkynylthiocarbonyl group having 3 to 12 carbon atoms, an arylthiocarbonyl group having 7 to 12 carbon atoms, and a heteroary having 3 to 12 carbon atoms Ruthiocarbonyl group, alkylthioalkoxy group, —O—N═CR ^3
2 R ³³ , —N (OR ³⁴ ) —CO—R ³⁵ and a group represented by the following (formula e) (R ³² and R ³³ , and R ³⁴ and R ³⁵ are each an optionally substituted carbon number. A group selected from the group consisting of 1 to 12 alkyl groups which may be different from each other.

(In (formula e), R ³⁰ and R ³¹ each independently represents an optionally substituted alkyl group having 1 to 12 carbon atoms.)
R ⁴ is an optionally substituted alkanoyl group having 2 to 12 carbon atoms, an alkenoyl group having 3 to 25 carbon atoms, a cycloalkanoyl group having 3 to 8 carbon atoms, an aryloyl group having 7 to 20 carbon atoms, carbon This represents a group selected from the group consisting of a heteroarylloyl group having 3 to 20 carbon atoms, an alkoxycarbonyl group having 2 to 10 carbon atoms, and an aryloxycarbonyl group having 7 to 20 carbon atoms. )

(In the formula (f), R ⁵ represents a hydrogen atom; an optionally substituted alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 25 carbon atoms, or a heteroaryl group having 3 to 20 carbon atoms. Or a heteroarylalkyl group having 4 to 25 carbon atoms; or a group that binds to Y ¹ or Z to form a ring.
R ⁶ is an alkanoyl group having 2 to 20 carbon atoms, an alkenoyl group having 3 to 25 carbon atoms, a cycloalkanoyl group having 4 to 8 carbon atoms, an aryloyl group having 7 to 20 carbon atoms, or an alkoxycarbonyl group having 2 to 10 carbon atoms. , An aryloxycarbonyl group having 7 to 20 carbon atoms, a heteroaryl group having 2 to 20 carbon atoms, a heteroaryloyl group having 3 to 20 carbon atoms, or an alkylaminocarbonyl group having 2 to 20 carbon atoms, which are all It may have a substituent.
Y ¹ represents a divalent aromatic hydrocarbon group and / or an aromatic hetero group formed by condensation of two or more rings which may have a substituent.
Z represents an aromatic group which may have a substituent. )

Among the compounds represented by the above (formula d) or (formula f), those having a ketoxime structure are more preferable. Specific examples include 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime) ethanone, 1- [9-ethyl-6- (2-methyl). And benzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime) glutarate methyl, or compounds described in JP2010-8713A and JP2009-271502A.

-Other photoinitiators As a photoinitiator, photoinitiators other than the said oxime ester system photoinitiator can be used together. For example, any of the following cationic photopolymerization initiators, anionic photopolymerization initiators, and radical photopolymerization initiators can be used as long as they correspond to the polymerizable monomers to be used. Any of these may be used alone or in combination of two or more.

However, it is preferable to use a radical photopolymerization initiator because it is difficult to inhibit the reaction forming the matrix. Of these, phosphine oxide compounds are more preferred.
The photopolymerization initiator is more preferably a compound having a molar extinction coefficient at a recording wavelength of 1000 L · mol ⁻¹ · cm ⁻¹ or less. When the molar extinction coefficient is greater than 1000 L · mol ⁻¹ · cm ⁻¹ , when the amount capable of obtaining sufficient diffraction efficiency is mixed, the transmittance of the hologram recording medium at the recording wavelength may be lowered.

(Cationic photopolymerization initiator)
As the cationic photopolymerization initiator, any known cationic photopolymerization initiator can be used. Examples include aromatic onium salts. Specific examples include anion components such as SbF ₆ ⁻ , BF ₄ ⁻ , AsF ₆ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , B (C ₆ F ₅ ) ₄ ⁻ , iodine, sulfur, nitrogen, phosphorus, and the like. The compound which consists of an aromatic cation component containing these atoms is mentioned. Of these, diaryl iodonium salts, triaryl sulfonium salts and the like are preferable. Any one of the above-exemplified cationic photopolymerization initiators may be used alone, or two or more thereof may be used in any combination and ratio.

(Anionic photopolymerization initiator)
Any anionic photopolymerization initiator may be used as long as it is a known anionic photopolymerization initiator. Examples include amines. Examples of amines include amino group-containing compounds such as dimethylbenzylamine, dimethylaminomethylphenol, 1,8-diazabicyclo [5.4.0] undecene-7, and derivatives thereof; imidazole, 2-methylimidazole, Imidazole compounds such as 2-ethyl-4-methylimidazole, and derivatives thereof; Any one of the anionic photopolymerization initiators exemplified above may be used alone, or two or more may be used in any combination and ratio.

(Radical photopolymerization initiator)
As the radical photopolymerization initiator, any known radical photopolymerization initiator can be used. Examples include phosphine oxide compounds, azo compounds, azide compounds, organic peroxides, organoborates, onium salts, bisimidazole derivatives, titanocene compounds, iodonium salts, organic thiol compounds, halogenated hydrocarbon derivatives, etc. . Any one of the radical photopolymerization initiators exemplified above may be used alone, or two or more of them may be used in any combination and ratio. As described above, phosphine oxide compounds are particularly preferable.

The type of the phosphine oxide compound is not particularly limited as long as the object and effect of the present invention are not impaired, and among them, an acyl phosphine oxide compound is preferable.
Examples of the acylphosphine oxide compound include monoacylphosphine oxide represented by the following (formula b) or diacylphosphine oxide represented by the following (formula c). Any of these may be used alone, or two or more of these may be used in any combination and ratio.

(In (Formula b), R ⁷ is an alkyl group having 1 to 18 carbon atoms; an alkyl group having 1 to 4 carbon atoms substituted with a halogen or an alkoxy group having 1 to 6 carbon atoms; A cycloalkyl group, a phenylalkyl group having 7 to 9 carbon atoms, a phenyl group, a naphthyl group, or a biphenyl group; selected from the group consisting of halogen, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms A phenyl group, a naphthyl group or a biphenyl group substituted with at least one; a 5- or 6-membered heterocyclic group containing monovalent N, O or S;

R ⁸ is a phenyl group; a naphthyl group; a biphenyl group; a phenyl group substituted with at least one selected from the group consisting of halogen, an alkyl group having 1 to 12 carbon atoms and an alkoxy group having 1 to 12 carbon atoms; Naphthyl group or biphenyl group; 5- or 6-membered heterocyclic group containing monovalent N, O or S; alkoxy group having 1 to 18 carbon atoms; phenoxy group; halogen, alkyl group having 1 to 4 carbon atoms Or a phenoxy group, a benzyloxy group, or a cyclohexyloxy group, which is substituted with an alkoxy group having 1 to 4 carbon atoms. R ⁸ and R ⁷ may be combined with a phosphorus atom to form a ring.

R ⁹ is an alkyl group having 1 to 18 carbon atoms; substituted with a halogen or an alkoxy group having 1 to 6 carbon atoms, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 5 to 8 carbon atoms, or a carbon number 7-9 phenylalkyl group, phenyl group, naphthyl group, biphenyl group; substituted with at least one selected from the group consisting of halogen, alkyl group having 1 to 12 carbon atoms and alkoxy group having 1 to 12 carbon atoms A phenyl group, a naphthyl group or a biphenyl group; a 5- or 6-membered heterocyclic group containing monovalent N, O or S; or a group represented by the following (formula b-1):

(In (Formula b-1), B ¹ is an alkylene group having 2 to 8 carbon atoms or a cyclohexylene group; unsubstituted or substituted with a halogen, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. R ^{7 ′} and R ^{8 ′} represent the same groups as those described for R ⁷ and R ⁸ in the above (formula b), where (formula b) And R ⁷ and R ^{7 ′} , R ⁸ and R ^{8 ′} may be the same or different.))

(In (Formula c), R ¹⁰ is an alkyl group having 1 to 18 carbon atoms; an alkyl group having 1 to 4 carbon atoms substituted with a halogen or an alkoxy group having 1 to 6 carbon atoms; A cycloalkyl group, a phenylalkyl group having 7 to 9 carbon atoms, a phenyl group, a naphthyl group, or a biphenyl group; selected from the group consisting of halogen, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms A phenyl group, a naphthyl group or a biphenyl group substituted with at least one; a 5- or 6-membered heterocyclic group containing monovalent N, O or S, an alkoxy group having 1 to 18 carbon atoms, or A phenoxy group; a phenoxy group, a benzyloxy group, or a cyclohexyloxy group substituted with a halogen, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms A group;

R ¹¹ and R ¹² are each independently an alkyl group having 1 to 18 carbon atoms; an alkyl group having 1 to 4 carbon atoms substituted with a halogen or an alkoxy group having 1 to 6 carbon atoms; An alkyl group, a phenylalkyl group having 7 to 9 carbon atoms, a phenyl group, a naphthyl group, or a biphenyl group; at least one selected from the group consisting of halogen, an alkyl group having 1 to 12 carbon atoms, and an alkoxy group having 1 to 12 carbon atoms A phenyl group, a naphthyl group or a biphenyl group substituted with one group; a 5- or 6-membered heterocyclic group containing monovalent N, O or S; )

Specific examples of the compound represented by the above (formula b) or (formula c) include 2,4,6-trimethylbenzoyl diphenylphosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, 2,6-dimethoxy. Benzoylethoxyphenylphosphine oxide, 2,6-dichlorobenzoylethoxyphosphine oxide, 2,6-dichlorobenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl)-(2,4,4-trimethyl-pent-1-yl ) -Phosphine oxide, bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphine oxide, bis (2,4,6- Trimethylbenzoyl)- 2,4-dipentyl-oxy phenyl) phosphine oxide and the like.
Among these, a monoacylphosphine oxide compound is preferable because excellent recording sensitivity can be obtained.

1-5. Rare earth catalyst As the rare earth catalyst acting as a matrix curing catalyst, a catalyst having a structure containing a rare earth element and promoting the reaction of a compound having an isocyanate group and a compound having an isocyanate reactive functional group is preferably used. .

  Rare earth elements are 17 elements of scandium, yttrium and lanthanoids belonging to group 3A of the periodic table, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium. is there. Among these, from the viewpoint of storage stability (shelf life) of the hologram recording medium, a catalyst containing an element belonging to a lanthanoid is preferable. Among these, a catalyst containing light rare earth is preferable, and a catalyst containing lanthanum (La) and praseodymium (Pr) is more preferable.

  Catalysts containing lanthanum (La) include lanthanum acetate, lanthanum carbonate, lanthanum nitrate, lanthanum sulfate, lanthanum oxalate, lanthanum phosphate, lanthanum trifluoroacetate, lanthanum stearate, lanthanum naphthenate, lanthanum neodecanoate, 2-ethyl Lanthanum hexanoate, lanthanum trifluoromethanesulfonate, lanthanum chloranilate, lanthanum chloride, lanthanum iodide, lanthanum fluoride, lanthanum bromide, lanthanum oxide, lanthanum hydroxide, methoxy lanthanum, ethoxy lanthanum, isopropoxylantan, butoxylantan, Ethylenediaminetetraacetic acid lanthanum, ethylenediaminepentaacetic acid lanthanum, nitrilotriacetic acid lanthanum, 2,4-pentanedionatlantan, 3-methyl-2,4-pentanedionatlantan, 2,3-pentanedionate Pentane, and the like.

  Among them, a compound having an organic compound as a ligand is preferable from the viewpoint of compatibility with a resin matrix, and a compound having a chelate compound as a ligand that forms a stable complex with a rare earth element is more preferable. Any one of the above curing catalysts may be used alone, or two or more thereof may be used in any combination and ratio.

Examples of the catalyst containing praseodymium (Pr) include praseodymium acetate, praseodymium carbonate, praseodymium nitrate, praseodymium sulfate, praseodymium oxalate, praseodymium phosphate, praseodymium trifluoroacetate, praseodymium stearate, praseodymium naphthenate, praseodymium neodecanoate, 2-ethyl Praseodymium hexanoate, praseodymium trifluoromethanesulfonate, praseodymium chloranilate, praseodymium chloride, praseodymium iodide, praseodymium fluoride, praseodymium bromide, praseodymium oxide, praseodymium hydroxide, methoxy praseodymium, ethoxy praseodymium, isopropoxy praseodymium, butoxy praseodymium, Ethylenediaminetetraacetic acid praseodymium, ethylenediaminepentaacetic acid praseodymium, nitrilotriacetic acid praseeo Arm, 2,4-pentanedionato praseodymium, 3-methyl-2,4-pentanedionato praseodymium, 2,3-pentanedionato praseodymium, and the like.

Among them, a compound having an organic compound as a ligand is preferable from the viewpoint of compatibility with a resin matrix, and a compound having a chelate compound as a ligand that forms a stable complex with a rare earth element is more preferable. Any one of the above curing catalysts may be used alone, or two or more thereof may be used in any combination and ratio.
1-6. Others The composition for a hologram recording medium in the present invention is characterized by containing the above-mentioned components (1) to (5), but may contain other components unless contrary to the gist of the present invention.

-Other catalyst The composition for hologram recording media of the present invention may use other curing catalysts together with the matrix curing catalyst for adjusting the reaction rate. The catalyst that can be used in combination is not particularly limited as long as it is not contrary to the gist of the present invention, but it is preferable to use a bismuth catalyst or a compound having an amino group in a part of its structure.

  An example of the bismuth-based catalyst is not particularly limited as long as it is a catalyst containing a bismuth element and serves as a Lewis acid that promotes the reaction of a compound having an isocyanate group and a compound having an isocyanate-reactive functional group. For example, tris (2-ethylhexanato) bismuth, tribenzoyloxybismuth, bismuth triacetate, bismuth tris (dimethyldiocarbamate), bismuth hydroxide, triphenylbismuth (V) bis (trichloroarate), tris (4 -Methylphenyl) oxobismuth (V), triphenylbis (3-chlorobenzoyloxy) bismuth (V) and the like.

Among them, trivalent bismuth compounds are preferable from the viewpoint of catalytic activity, and bismuth carboxylate, general formula Bi (OCOR) ₃ (R is a linear or branched alkyl group, cycloalkyl group, or substituted or unsubstituted aromatic group). Is more preferable. Any one of the above bismuth catalysts may be used alone, or two or more thereof may be used in any combination and ratio.

  Examples of compounds having an amino group as part of the structure include triethylamine (TEA), N, N-dimethylcyclohexylamine (DMEDA), N, N, N ′, N′-tetramethylethylenediamine (TMEDA), N, N, N ′, N′-tetramethylpropane 1,3-diamine (TMPDA), N, N, N ′, N′-tetramethylhexane-1,6-diamine (TMHMDA), N, N, N ′, N ″, N ″ -pentamethyldiethylenetriamine (PMDETA), N, N, N ′, N ″, N ″ -pentamethyldipropylene-triamine (PMDPTA), triethylenediamine (TEDA), N, N′-dimethylpiperazine ( DMP), N, -methyl, N ′-(2dimethylamino) -ethylpiperazine (TMNAEP), N-methylmorpholine (NMMO), N · (N ′, N′-dimethylaminoethyl) -morpholine (DMAEMO), bis (2-dimethylaminoethyl) ether (BDMEE), ethylene glycol bis (3-dimethyl) -aminopropyl ether (TMEGDA) And amine compounds such as diisopropylethylamine (DIEA). Any of these may be used alone, or two or more of these may be used in any combination and ratio.

Other components Other components include solvents, plasticizers, dispersants, leveling agents, antifoaming agents, adhesion promoters, etc. for preparing the recording layer of hologram recording media, and for recording reaction control. , Chain transfer agents, polymerization terminators, compatibilizers, reaction aids, sensitizers, antioxidants and the like. Any one of these components may be used alone, or two or more thereof may be used in any combination and ratio.

  Among them, it is preferable to use a leveling agent. Examples of the leveling agent include polycarboxylic acid sodium salt, polycarboxylic acid ammonium salt, polycarboxylic acid amine salt, silicon-based leveling agent, acrylic leveling agent, ester compound, ketone compound, and fluorine compound. Any one of these compounds may be used alone, or two or more thereof may be used in any combination and ratio.

1-7. Composition ratio of each component in the composition for hologram recording medium The amount of each component used in the composition for hologram recording medium of the present invention is arbitrary as long as it is not contrary to the gist of the present invention. The following ranges are preferable based on the total mass. The usage-amount of a component (1) and a component (2) is 0.1 mass% or more normally in total, Preferably it is 10 mass% or more, More preferably, it is 35 mass% or more. Moreover, it is 99.9 mass% or less normally, Preferably it is 99 mass% or less. If the amount used is less than the lower limit, it may be difficult to form a recording layer.

The ratio of the number of isocyanate-reactive functional groups in component (2) to the number of isocyanate groups in component (1) is preferably 0.1 or more, more preferably 0.5 or more. Moreover, it is 2.0 or less normally, Preferably it is 1.5 or less. If this ratio is too large or too small, there are many unreacted functional groups, and storage stability may be lost.
The usage-amount of a component (3) is 0.1 mass% or more normally, Preferably it is 1 mass% or more, More preferably, it is 2 mass% or more. Moreover, it is 80 mass% or less normally, Preferably it is 50 mass% or less, More preferably, it is 30 mass% or less. If the amount of the component (3) is too small, sufficient diffraction efficiency cannot be obtained, and if it is too large, the compatibility of the recording layer may be impaired.

The usage-amount of a component (4) is 0.001 mass% or more normally, Preferably it is 0.01 mass% or more, and is 5 mass% or less normally, Preferably it is 3 mass% or less. If the amount of component (4) is too small, sufficient recording sensitivity may not be obtained.
The amount of component (5) used is preferably determined in consideration of the reaction rates of component (1) and component (2), and is usually 5% by mass or less, preferably 4% by mass or less, more preferably 1% by mass or less. It is. Moreover, it is preferable to use 0.005 mass% or more.

The total amount of other components other than components (1) to (5) may be 30% by mass or less, preferably 15% by mass or less, and more preferably 5% by mass.
1-8. Method for Producing Hologram Recording Medium Composition In the present invention, the components (1) to (5) may be mixed in any combination and order, and at that time, other components may be combined and mixed. Good.

For example, it can be obtained by the following method, but the present invention is not limited thereto.
All components other than the component (2) and the component (5) are mixed to obtain a liquid A. A mixture of component (2) and component (5) is designated as B liquid. Each liquid is preferably dehydrated and degassed. If dehydration / deaeration is not performed or insufficient, bubbles may be generated when the medium is produced, and a uniform recording layer may not be obtained. As long as each component is not damaged during this dehydration and deaeration,
Heating and decompression may be performed.

  Mixing of liquid A and liquid B is performed immediately before molding. At this time, it is also possible to use a mixing technique by a conventional method. When mixing the liquid A and the liquid B, deaeration may be performed as necessary to remove the residual gas. Furthermore, in order to remove a foreign material and an impurity after mixing each of A liquid and B liquid, it is preferable to pass a filtration process, and it is more preferable to filter each liquid separately. As component (1) ', it is also possible to use an isocyanate-functional prepolymer resulting from the reaction of excess component (1) and component (2). Furthermore, an isocyanate-reactive prepolymer obtained by reacting an excess of component (2) with component (1) can also be used as component (2) '.

1-9. Preferred Combination of Photopolymerization Initiator and Matrix Curing Catalyst In the present invention, the photopolymerization initiator and the matrix curing catalyst can be arbitrarily combined. Preferred is an oxime ester photopolymerization initiator alone, or a combination of an oxime ester photopolymerization initiator and a phosphine oxide compound and a rare earth catalyst, and more preferably an oxime ester photopolymerization initiator alone or oxime ester light. A combination of a polymerization initiator and a phosphine oxide compound with a lanthanum-based catalyst and / or a praseodymium-based catalyst.

2. About the hologram recording medium of the present invention The hologram recording medium of the present invention further comprises a recording layer and, if necessary, a support and other layers. Usually, the hologram recording medium has a support, and the recording layer and other layers are laminated on the support to constitute the hologram recording medium. However, when the recording layer or other layers have the strength and durability required for the medium, the hologram recording medium may not have a support. Examples of other layers include a protective layer, a reflective layer, an antireflection layer (antireflection film), and the like.
The recording layer of the hologram recording medium of the present invention is preferably formed from the composition for a hologram recording medium of the present invention.

2-1. Recording layer The recording layer of the hologram recording medium of the present invention is a layer formed from the composition for a hologram recording medium of the present invention, and is a layer on which information is recorded. Information is usually recorded as a hologram. As described in detail in the section of the recording method to be described later, a part of the polymerizable monomer contained in the recording layer causes a chemical change such as polymerization by hologram recording or the like. Therefore, in the hologram recording medium after recording, a part of the polymerizable monomer is consumed and exists as a compound after reaction such as a polymer.

The thickness of the recording layer is not particularly limited and may be appropriately determined in consideration of the recording method and the like. Generally, it is generally 1 μm or more, preferably 10 μm or more, and usually 3000 μm or less, preferably 2000 μm or less. It is a range. If the recording layer is too thin, the selectivity of each hologram is lowered during multiplex recording on the hologram recording medium, and the degree of multiplex recording may be reduced. If the recording layer is too thick, it is difficult to uniformly mold the entire recording layer, and it may be difficult to perform multiplex recording with uniform diffraction efficiency of each hologram and a high S / N ratio.
Further, it is preferable that the shrinkage rate of the recording layer due to exposure during recording and reproduction of information is 0.25% or less.

2-2. Support The support is not particularly limited in detail as long as it has the strength and durability required for the medium, and any support can be used. Moreover, although there is no restriction | limiting also in the shape of a support body, Usually, it forms in flat form or a film form. Moreover, there is no restriction | limiting in the material which comprises a support body, Transparent or opaque may be sufficient. Examples of transparent materials for the support include organic materials such as acrylic, polyethylene terephthalate, polyethylene naphthoate, polycarbonate, polyethylene, polypropylene, amorphous polyolefin, polystyrene, and cellulose acetate; and inorganic materials such as glass, silicon, and quartz. It is done. Among these, polycarbonate, acrylic, polyester, amorphous polyolefin, glass, and the like are preferable, and polycarbonate, acrylic, amorphous polyolefin, and glass are particularly preferable.

On the other hand, when the opaque material is cited as the material of the support, a metal such as aluminum; a metal such as gold, silver or aluminum or a dielectric such as magnesium fluoride or zirconium oxide is coated on the transparent support. Things.
Although there is no restriction | limiting in particular also in the thickness of a support body, Usually, it is preferable to set it as the range of 0.05 mm or more and 1 mm or less. If the support is too thin, the mechanical strength of the hologram recording medium may be insufficient and the substrate may be warped. If the support is too thick, the amount of transmitted light may be reduced and the cost may be increased.

  Moreover, you may surface-treat on the surface of a support body. This surface treatment is usually performed to improve the adhesion between the support and the recording layer. Examples of the surface treatment include subjecting the support to corona discharge treatment or forming an undercoat layer on the support in advance. Here, examples of the composition of the undercoat layer include halogenated phenols, partially hydrolyzed vinyl chloride-vinyl acetate copolymers, polyurethane resins, and the like.

Furthermore, the surface treatment may be performed for purposes other than the improvement of adhesiveness. Examples thereof include a reflective coating treatment for forming a reflective coating layer made of a metal such as gold, silver, and aluminum; a dielectric coating treatment for forming a dielectric layer such as magnesium fluoride and zirconium oxide, and the like. It is done. These layers may be formed as a single layer or two or more layers.
These surface treatments may be provided for the purpose of controlling the gas and moisture permeability of the substrate. For example, the reliability of the medium can be further improved by providing the support sandwiching the recording layer with the function of suppressing the permeability of gas and moisture.

Further, the support may be provided only on either the upper side or the lower side of the recording layer of the hologram recording medium of the present invention, or may be provided on both. However, when providing a support on both the upper and lower sides of the recording layer, at least one of the supports is configured to be transparent so as to transmit active energy rays (excitation light, reference light, reproduction light, etc.).
In the case of a hologram recording medium having a support on one side or both sides of the recording layer, a transmissive or reflective hologram can be recorded. When a support having reflection characteristics is used on one side of the recording layer, a reflection hologram can be recorded.

  Furthermore, patterning for data addresses may be provided on the support. Although there is no restriction | limiting in the patterning method in this case, For example, an unevenness | corrugation may be formed in support body itself, a pattern may be formed in the reflective layer mentioned later, and you may form by the method of combining these.

2-3. Protective layer The protective layer is a layer for preventing the influence of deterioration of storage stability due to oxygen and moisture of the recording layer. There is no restriction | limiting in the specific structure of a protective layer, It is possible to apply a well-known thing arbitrarily. For example, a layer made of a water-soluble polymer, an organic / inorganic material, or the like can be formed as a protective layer.
The formation position of the protective layer is not particularly limited. For example, the protective layer may be formed on the surface of the recording layer, between the recording layer and the support, or on the outer surface side of the support. Moreover, you may form between a support body and another layer.

2-4. Reflective layer The reflective layer is formed when the hologram recording medium is configured to be reflective. In the case of a reflection-type hologram recording medium, the reflection layer may be formed between the support and the recording layer, or may be formed on the outer surface of the support. Usually, the support and the recording layer are used. It is preferable to be between.
As the reflective layer, a known layer can be arbitrarily applied. For example, a metal thin film or the like can be used.

2-5. Antireflection film For both transmissive and reflective hologram recording media, an antireflection film may be provided on the side on which object light and readout light enter and exit, or between the recording layer and the support. The antireflection film functions to improve light utilization efficiency and suppress the generation of ghost images.
Any known antireflection film can be used.

2-6. Method for producing hologram recording medium The method for producing the hologram recording medium of the present invention is not limited. For example, it can be produced by applying the composition for a hologram recording medium of the present invention on a support without solvent and forming a recording layer. At this time, any method can be used as a coating method. Specific examples include a spray method, a spin coat method, a wire bar method, a dip method, an air knife coat method, a roll coat method, a blade coat method, and a doctor roll coat method. In forming the recording layer, when a recording layer having a particularly large thickness is formed, it is possible to use a method of molding in a mold or a method of coating on a release film and punching out of the mold. Alternatively, the composition for hologram recording medium of the present invention and a solvent or additive may be mixed to prepare a coating solution, which may be coated on a support and dried to form a recording layer. In this case as well, any method can be used as the coating method, and for example, the same method as described above can be adopted.

  Moreover, although there is no restriction | limiting in a solvent, Usually, it is preferable to use what has sufficient solubility with respect to a use component, gives favorable coating film property, and does not attack a support body, such as a resin substrate. Examples of solvents include ketone solvents such as acetone and methyl ethyl ketone; aromatic solvents such as toluene and xylene; alcohol solvents such as methanol and ethanol; ketone alcohol solvents such as diacetone alcohol; tetrahydrofuran, Ether solvents such as dichloromethane, halogen solvents such as chloroform, cellosolv solvents such as methyl cellosolve and ethyl cellosolve; propylene glycol solvents such as propylene glycol monomethyl ether and propylene glycol monoethyl ether; ethyl acetate, 3- Ester solvents such as methyl methoxypropionate; perfluoroalkyl alcohol solvents such as tetrafluoropropanol; highly polar solvents such as dimethylformamide and dimethyl sulfoxide; n-hexane, etc. Jo hydrocarbon solvents; cyclohexane, cyclic hydrocarbon solvents cyclooctane; and or a solvent mixture thereof. In addition, a solvent may be used individually by 1 type and may use 2 or more types together by arbitrary combinations and a ratio. Moreover, there is no restriction | limiting in the usage-amount of a solvent. However, it is preferable to prepare a coating solution having a solid content concentration of about 1% to 1000% by weight from the viewpoint of coating efficiency and handleability.

  Further, when the resin matrix comprising the components (1) and (2) of the composition for a hologram recording medium of the present invention is thermoplastic, the hologram recording of the present invention is performed by, for example, an injection molding method, a sheet molding method, a hot press method, or the like. A medium composition is formed. In the case where the resin matrix comprising the components (1) and (2) of the present invention is a (light) thermosetting with a small amount of volatile components, the photoreactive composition of the present invention can be obtained by, for example, reaction injection molding or liquid injection molding. The recording layer can be manufactured by molding a product. In this case, if the molded body has sufficient thickness, rigidity, strength, etc., the molded body can be used as it is as a hologram recording medium.

Further, as a method for producing a hologram recording medium, for example, a method for producing a hologram recording medium by forming a recording layer by applying a composition for a hologram recording medium melted by heat to a support and solidifying by cooling, a liquid hologram recording A method for producing a recording layer by applying a composition for a medium to a support and curing it by thermal polymerization, and curing by applying a liquid composition for a hologram recording medium to a support and photopolymerizing it. And a method of manufacturing the recording layer by forming the recording layer.

  The hologram recording medium thus manufactured can take the form of a self-supporting slab or a disk, and can be used for a three-dimensional image display device, a diffractive optical element, a large-capacity memory, and the like.

2-7. Information Recording / Reproducing Method Information is written (recorded) and read (reproduced) on the hologram recording medium of the present invention by light irradiation.
First, when recording information, light capable of causing a chemical change of a polymerizable monomer, that is, polymerization and concentration change, is used as object light (also referred to as recording light).
For example, when recording information as a volume hologram, the object light is irradiated onto the recording layer together with the reference light so that the object light and the reference light interfere with each other in the recording layer. As a result, the interference light causes polymerization and concentration change of the polymerizable monomer in the recording layer, and as a result, the interference fringes cause a refractive index difference in the recording layer, and the interference recorded in the recording layer. A hologram is recorded on the recording layer by the stripes.

On the other hand, when reproducing the volume hologram recorded on the recording layer, the recording layer is irradiated with predetermined reproduction light (usually reference light). The irradiated reproduction light is diffracted according to the interference fringes. Since the diffracted light contains the same information as the recording layer, the information recorded on the recording layer can be reproduced by reading the diffracted light with an appropriate detection means. Note that the wavelength ranges of the object light, the reproduction light, and the reference light are arbitrary depending on each application, and may be a visible light region or an ultraviolet region. These as preferable even Among light, for example, ruby, glass, Nd-YAG, a solid-state laser such as a _{Nd-YVO 4; GaAs, InGaAs} , such as GaN diode lasers; helium - neon, argon, krypton, excimer, Examples thereof include a gas laser such as CO ₂ ; a laser having excellent monochromaticity and directivity, such as a dye laser having a dye.

Further, there is no limitation on the irradiation amounts of the object light, the reproduction light, and the reference light, and the irradiation amounts are arbitrary as long as they can be recorded and reproduced. However, if the amount is extremely small, the chemical change of the polymerizable monomer may be too incomplete, and the heat resistance and mechanical properties of the recording layer may not be sufficiently expressed. The component of the composition for a hologram recording medium of the present invention may deteriorate. Accordingly, the object light, the reproduction light, and the reference light are usually 0.1 J in accordance with the composition of the composition for hologram recording medium of the present invention used for forming the recording layer, the kind of photoinitiator, the blending amount, and the like. Irradiation is in the range of not less than / cm ^{2 and not} more than 20 J / cm ² .
The hologram recording system includes a polarization collinear hologram recording system, a reference light incident angle multiplexing type hologram recording system, etc., but any recording system is satisfactory when the hologram recording medium of the present invention is used as a recording medium. It is possible to provide recording quality.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to a following example, unless it deviates from the summary.
[Example 1]
-Preparation of composition for hologram recording medium To 2.89 g of hexamethylene diisocyanate adduct body, 0.22 g of dibenzothiophenyl phenyl acrylate (2,4-bis (4-dibenzothiophenyl) -1-phenyl (meth) acrylate), And 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl] -1- (O-acetyloxime) methyl glutarate 0.0
23g was dissolved and it was set as A liquid.

Next, 0.0014 g of 2,4-pentanedionatlantan as a curing catalyst was dissolved in 4.10 g of polyoxypropylene glycol having a molecular weight of about 1000 to obtain a liquid B.
Liquid B was degassed under reduced pressure for 3 hours, and then liquid A and liquid B were mixed and stirred and mixed, and further degassed in vacuum for several minutes.

・ Preparation of measurement sample Next, pour the vacuum degassed mixture onto a glass slide with a 500μm thick spacer sheet on the two ends, cover the glass slide on it, and use clips to surround it. Was fixed and heated at 60 ° C. for 48 hours to prepare a hologram recording medium for measurement. In this measurement sample, a recording layer having a thickness of 500 μm is formed between slide glasses as a cover.
The sample obtained in this manner was evaluated for hologram recording characteristics. The conditions for evaluation are as follows.

[Hologram recording]
Using the obtained hologram recording evaluation sample, hologram recording was performed according to the procedure described below.
Using a semiconductor laser having a wavelength of 405 nm, hologram recording of a two-beam plane wave was performed using the exposure apparatus shown in FIG. 2 at an exposure power density of 6.0 mW / cm ² per beam.
The medium is recorded 61 times in the same place from -30 ° to 30 ° at intervals of 1 °, and the sum of the square roots of diffraction efficiency at that time is defined as M / # (M number). The light transmittance at the recording wavelength was measured before and after the recording. Details will be described below.

2A is a configuration diagram showing an outline of the apparatus used for hologram recording, FIG. 2B is a configuration diagram showing the surface of the LED unit, and FIG. 2C is a diagram of the surface of the LED unit. It is a block diagram which shows the arrangement | sequence of LED.
In FIG. 2A, S represents a sample of the hologram recording medium, M1 to M3 all represent mirrors, PBS represents a polarizing beam splitter, and L1 represents a laser light source for recording light that emits light having a wavelength of 405 nm (wavelength). 1 represents a single-mode laser diode manufactured by Sony that can obtain light of around 405 nm (“L1” in FIG. 2A)), L2 represents a laser light source for reproducing light that emits light having a wavelength of 633 nm, and PD1, PD2 Indicates a photodetector. Reference numeral 1 denotes an LED unit, 2 denotes an arm, and 3 denotes a support.

  In the case of normal recording and reproduction, the LED unit is at the position of the solid line in FIG. 2A, and in the case of uniform exposure, as shown by the broken line, the arm 2 and the LED unit 1 to which the support column 3 is rotated are attached. After the LED moves to the front side of the recording portion of the sample S, the LED lights up for a certain period of time. As shown in FIG. 2 (c), the LEDs 1B are arranged on the LED unit surface 1A like dice 5 as dice. A power source is connected to the light sources L1 and L2, the photodetectors PD1 and PD2, and the LED unit 1.

  As shown in FIG. 2A, light having a wavelength of 405 nm is divided by a polarizing beam splitter (“PBS” in the figure), and the angle formed by the two beams is 37.0 ° on the recording surface. Crossed. At this time, the bisector of the angle formed by the two beams is perpendicular to the recording surface, and the vibration planes of the electric field vectors of the two beams obtained by the division are two intersecting lines. Irradiation was performed so as to be perpendicular to the plane including the beam.

After hologram recording, using a He-Ne laser that can obtain light having a wavelength of 633 nm (V05-LHP151 manufactured by Meles Griot, "L2" in the figure), the light is 29.
Hologram recording by irradiating at an angle of 9 ° and detecting diffracted light using a power meter and detector (Newport 2930-C, 918-SL: “PD1” and “PD2” in the figure)) It was determined whether or not was done correctly. The diffraction efficiency of a hologram is given by the ratio of the intensity of diffracted light to the sum of transmitted light intensity and diffracted light intensity.

(Measurement of M / #)
The angle at which the sample is moved with respect to the optical axis (the angle between the two light fluxes, that is, the angle between the bisector of the inner angle at the point where the incident light from the mirrors M1 and M2 in FIG. 2A intersects) and the normal from the sample. 61 multiple recordings were performed in 1 degree increments from −30 ° to 30 °, and the sum of the obtained square roots of diffraction efficiency over the entire multiple recording region was defined as M / #.

  Specifically, for each example, using one of a plurality of optical recording media prepared first, the angle between the bisector of the inner angle at the point where the two light beams intersect and the normal of the medium is zero. Until the diffraction efficiency becomes constant, the two light beams, that is, the incident light from the mirrors M1 and M2 in FIG. 2A and the wavelength of 405 nm are irradiated, and the constant minimum energy is measured (at this time, evaluation of the diffraction efficiency) Is performed using light from the mirror M3 and a wavelength of 633 nm).

  Next, with respect to another sample, multiple recording is performed using the previously obtained minimum energy value as a measure of the total irradiation energy for 61 multiple recording. At this time, the irradiation energy is appropriately adjusted according to the number of times of recording, and a diffraction efficiency of several percent for each recording is maintained. After 61 multiple recording, the light (wavelength 405 nm) from the mirror M1 in FIG. 2A is subsequently irradiated, the diffraction efficiency from angles -30 ° to 30 ° is measured, and the sum of the square roots of the diffraction efficiencies at each angle ( M / #).

  While changing the sample, performing multiple evaluations with different irradiation energy conditions such as increase / decrease in irradiation energy at the beginning of recording and increase / decrease in total irradiation energy, while maintaining diffraction efficiency of several percent or more for each recording, 61 A search was made for a condition in which the contained monomer was almost completely consumed before multiple recording (M / # almost reached equilibrium by 61 multiple recording), and the maximum value was obtained as M / #. The maximum value obtained was defined as M / # of the medium.

(sensitivity)
The sensitivity of the sample for measurement represents the average sensitivity until reaching 80% of the maximum M / # indicated by the sample in the M / # measurement, and is calculated as follows.
Sensitivity = (0.8 × (M / #)) / (I × ts × L)
Here, I is the incident light intensity (mW / cm ² ), ts is the total exposure time (seconds) until M / # reaches 80%, and L is the recording layer thickness (cm).

(Light transmittance before recording, light transmittance after recording)
For light transmittance, after measuring the light intensity in the absence of any sample, place the sample vertically in the optical path and measure the light intensity again in a short time so that no chemical change occurs. The ratio was defined as light transmittance. In the case after recording, the sample was measured by placing the portion of the sample recorded at an angle perpendicular to the optical path and at which diffraction does not occur so that light can pass through. The wavelength was 405 nm, the same as recording, the intensity was 6 mW / cm ² , and the recording layer thickness was 500 μm.

(Storage stability test)
In the sample storage stability test, an unrecorded sample was recorded after being stored at 80 ° C. and compared with that before storage. M / # and sensitivity were evaluated based on the remaining rate with 100% before storage. The results are shown in Table 1 and FIG. Further, the transmittance before recording of the evaluation sample was evaluated by the difference between after storage and before storage. The results are shown in Table 1.

[Example 2]
A sample for measurement was prepared by preparing a composition for a hologram recording medium in the same manner as in Example 1 except that 2,4-pentanedionatopraseodymium was used as a curing catalyst instead of the curing catalyst in Example 1. Then, measurement and evaluation were performed. These results are shown in Table 1 and FIG.

[Comparative Example 1]
A hologram recording composition was prepared in the same manner as in Example 1 except that 0.0007 g of dioctyltin dilaurate was dissolved in place of the curing catalyst of Example 1, and a measurement sample was prepared and measured. And evaluated. These results are shown in Table 1 and FIG.
[Evaluation]

From the above table, storage stability (remaining ratio of M / #, residual ratio of sensitivity, and storage) when a rare earth catalyst, especially a lanthanoid catalyst, particularly a lanthanum (La) catalyst or praseodymium (Pr) catalyst is used. It is clear that the difference in transmittance before recording before and after the stability test is excellent.
From the above results, it is confirmed that the composition for hologram recording medium of the present invention and the hologram recording medium using the composition have excellent recording characteristics, little change in recording characteristics due to storage, and excellent storage stability (shelf life). It was.

  The composition for a hologram recording medium of the present invention and the hologram recording material using the composition are preferably used for applications such as a hologram recording medium.

1 LED unit
1A LED unit surface
1B LED
2 arms
3 props
S sample
M1, M2, M3 mirror
PBS Polarizing beam splitter
L1 Laser light source for recording light
L2 Laser light source for reproduction light
PD1, PD2 Photo detector

Claims (6)

A compound having an isocyanate group,
A compound having an isocyanate-reactive functional group,
Polymerizable monomer,
Photopolymerization initiator,
And a composition for a holographic recording medium, comprising a rare earth catalyst.   2. The composition for a hologram recording medium according to claim 1, wherein the rare earth catalyst is a lanthanoid catalyst.   The composition for a hologram recording medium according to claim 2, wherein the lanthanoid catalyst is a lanthanum catalyst.   The composition for a holographic recording medium according to claim 2, wherein the lanthanoid-based catalyst is a praseodymium-based catalyst.   The composition for a hologram recording medium according to any one of claims 1 to 4, wherein the polymerizable monomer is a radical polymerizable monomer.   A hologram recording medium comprising the hologram recording medium composition according to any one of claims 1 to 5 as a recording layer.

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