JP2016206488A - Composition for hologram recording medium and hologram recording medium using the same, and compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composition for hologram recording medium which includes a photoinitiator with little coloring being irradiated by light after recording while ensuring an excellent recording sensitivity and a storage stability, and a hologram recording medium using the composition for hologram recording medium.SOLUTION: The composition for hologram recording medium includes a compound which has a polymerizable reactive group and a photoinitiator. The photoinitiator is an oxime ester compound having a specific partial structure. A hologram recording medium using the composition for hologram recording medium is also provided.SELECTED DRAWING: None

Description

  The present invention relates to a composition for a hologram recording medium containing a photopolymerization initiator having a specific structure, a hologram recording medium using the composition, and a compound.

  In recent years, hologram recording media that have attracted attention are recording media that utilize light interference and diffraction phenomena. A hologram is a recording technique in which an interference pattern formed by interference fringes of two lights called reference light and information (or signal) light is recorded three-dimensionally inside a recording medium. The hologram recording medium includes a photosensitive hologram recording material in the recording layer, and information data is recorded by the chemical change of the hologram recording material according to the interference pattern and the local change of optical characteristics. There are several types depending on what optical properties are changed, but phase holograms (volume holograms) that record by creating a refractive index difference in the recording layer have high diffraction efficiency and wavelength selectivity. Is considered to be more advantageous.

As an example of the volume hologram recording material, there is a write-once type that does not require wet processing or bleaching processing. The material composition is generally a resin matrix in which a photoactive compound is compatible. For example, the composition which combined the monomer which can be radically polymerized or cationically polymerized as a photoactive compound with a resin matrix is mentioned (refer patent documents 1-4).
When recording a hologram, if there is a recording layer made of a composition containing a matrix resin, a polymerizable reactive compound, and a photopolymerization initiator at a portion where an interference fringe is formed by crossing the reference light and the information light In the interference fringes, the photopolymerization initiator causes a chemical reaction to become an active substance at a portion with high light intensity, and this acts on the polymerizable reactive compound to polymerize the reactive compound. At this time, if there is a difference in refractive index between the polymer formed from the matrix resin and the polymerizable reactive compound, the interference fringes become a refractive index difference and are fixed in the recording layer. Further, when the polymerizable reactive compound is polymerized, the reactive compound is diffused from the periphery, and the concentration distribution of the reactive compound or the polymer of the reactive compound is generated inside the recording layer. When the recording layer in this state is irradiated only with the reference light, the reproduction light corresponding to the information light recorded from the interference fringes is reproduced.

  Among the above-mentioned compositions, it is preferable to use a photopolymerization initiator having absorption in the range of 340 to 700 nm when using a laser in the blue-violet to visible light region. As such a photopolymerization initiator, it is known to use, for example, a titanocene compound, an acylphosphine oxide compound, an oxime ester photopolymerization initiator having a specific structure described in Patent Document 5, and the like. The oxime ester photopolymerization initiator has high recording sensitivity and excellent storage stability, and is expected to be a promising photopolymerization initiator for hologram recording media.

JP 11-352303 A JP 2005-43862 A JP-T-2005-502918 JP 2004-158117 A Special Table 2004-534797

The hologram recording medium is usually irradiated with light even after interference fringes are recorded on the recording layer by information light and reference light. Specifically, after recording the interference fringes, the recording layer is uniformly irradiated with light to consume residual monomers and initiators (hereinafter referred to as post-exposure) and the reference light This is the regeneration process in which irradiation is repeated. Therefore, it is necessary that the optical characteristics such as the transmittance of the recording layer do not change with the irradiation of these lights.

  On the other hand, the photopolymerization initiator is decomposed by irradiation with light, and accordingly, a reactive species is generated, and since it has a polymerization initiating ability, polymerization is induced. By-products are generated. This by-product may be colored by the irradiation of light after recording as described above. When such an initiator is used, the transmittance when reading recorded information is lowered, and the diffraction efficiency is lowered. There is a possibility that the performance will be deteriorated.

The above-mentioned oxime ester photopolymerization initiator is still insufficient with respect to the problem of coloring due to light irradiation after recording as described above.
The present invention has been made in view of the above problems, and its object is to provide a hologram recording including a photopolymerization initiator that is less colored by irradiation with light after recording while maintaining excellent recording sensitivity and storage stability. An object is to provide a medium composition and a hologram recording medium using the composition for hologram recording medium.

As a result of diligent research, the present inventors have introduced a specific partial structure in the oxime ester-based photopolymerization initiator to maintain excellent recording sensitivity and storage stability, and to perform hologram recording with little coloring. We found that the medium can be realized.
That is, the gist of the present invention is as follows [1] to [7].
[1] A hologram recording medium composition comprising a compound having a polymerizable reactive group and a photopolymerization initiator, wherein the photopolymerization initiator is represented by the following formula (1): Composition.

[R ¹ represents an alkyl group;
R ² represents any one of an alkyl group, an aryl group, and an aralkyl group,
R ³ represents a — (CH ₂ ) _n — group, n represents an integer of 1 to 6,
R ⁴ represents a hydrogen atom or an arbitrary substituent,
R ⁵ represents an arbitrary substituent having no multiple bond conjugated to the carbonyl group to be bonded. ]
[2] The composition for a hologram recording medium according to [1], wherein R ⁴ represents any one of an alkyl group, an alkoxycarbonyl group, an aromatic ring group, and a heterocyclic group.
[3] The composition for a hologram recording medium according to [1] or [2], wherein R ⁵ represents an alkyl group.
[4] The composition for a hologram recording medium according to any one of [1] to [3], further comprising a compound having an isocyanate group and / or a compound having an isocyanate-reactive functional group. [5] A hologram recording medium using the composition for a hologram recording medium according to any one of [1] to [4].
[6] A compound represented by the following formula (2).

[R ¹ represents an alkyl group;
R ² represents any one of an alkyl group, an aryl group, and an aralkyl group,
R ³ represents a — (CH ₂ ) _n — group, n represents an integer of 1 to 6,
R ⁴ represents an alkoxycarbonyl group,
R ⁵ represents a branched alkyl group. ]

  ADVANTAGE OF THE INVENTION According to this invention, the composition for hologram recording media with little coloring after light irradiation and a hologram recording medium using the same are obtained.

FIG. 1 is a configuration diagram showing an outline of an apparatus used for hologram recording.

  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. Further, the drawings used are used for explaining the embodiments of the present invention, and do not represent actual sizes.

1. Composition for hologram recording medium The composition for hologram recording medium of the present invention is used for forming a recording layer of a hologram recording medium. The composition for a hologram recording medium of the present invention is a composition comprising a compound having a polymerizable reactive group and a photopolymerization initiator represented by the following formula (1). The composition for hologram recording medium of the present invention is shown below.

1-1. The photoinitiator shown by Formula (1) The photoinitiator which concerns on this invention is shown by following formula (1).

In formula (1), R ¹ represents an alkyl group, R ² represents an alkyl group, an aryl group, or an aralkyl group, R ³ represents a — (CH ₂ ) _n — group, and n represents 1 represents an integer of 1 to 6, R ⁴ represents a hydrogen atom or an arbitrary substituent, and R ⁵ represents an arbitrary substituent having no multiple bond conjugated to a carbonyl group to be bonded. Hereinafter, the symbols in formula (1) will be described in detail.

<R ^1>
R ¹ represents an alkyl group. When R ¹ is other than an alkyl group such as an aromatic ring group, for example, the sp ² property of the nitrogen atom to which R ¹ is bonded increases, and conjugation from the carbazole ring of formula (1) to R ¹ is extended. Since light emission due to decomposition products after light irradiation occurs, an alkyl group having no such conjugated system is preferable.

Examples of the alkyl group for R ¹ include methyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, cyclopentyl, hexyl, and cyclohexyl. Group, heptyl group, octyl group, 2-ethylhexyl group, 3,5,5-trimethylhexyl group, decyl group, dodecyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cyclopropylmethyl group, cyclohexylmethyl group And linear, branched and cyclic alkyl groups such as 4-butylmethylcyclohexyl group. Among these, the number of carbon atoms is preferably 1 or more, more preferably 2 or more, and is preferably 18 or less, more preferably 8 or less, particularly a linear alkyl group having 1 to 4 carbon atoms. Is preferable from the viewpoint of crystallinity of the compound.

The alkyl group may have a substituent, and examples of the substituent that may be included include an alkoxy group, a dialkylamino group, a halogen atom, an aromatic ring group, and a heterocyclic group. Among these, an alkoxy group is preferable in terms of ease of controlling the solubility of the compound.
Preferable alkoxy groups include methoxy group, ethoxy group, n-propoxy group, isopropoxy group, cyclopentyl group, cyclohexyl group and the like.
In addition, an alkyl group substituted with a fluorine atom is preferable from the viewpoint of improving the water resistance of the compound because of increased water repellency.

<R ^2>
R ² represents any of an alkyl group, an aryl group, and an aralkyl group. R ² is a radical site generated when the photopolymerization initiator is irradiated with light, and is preferably an alkyl group having a small molecular weight from the viewpoint of ease of movement of radicals in the composition for hologram recording medium.
Specific examples of the alkyl group for R ² are the same as those for R ¹ described above, and the substituents that may be included are also the same. Among these, the number of carbon atoms is preferably 1 or more, and preferably 4 or less, more preferably 2 or less, from the viewpoint of radical mobility.

On the other hand, an aryl group is preferable from the viewpoint of improving the water resistance of the compound.
Specific examples of the aryl group for R ² include a phenyl group, a naphthyl group, an anthryl group, and an indenyl group. From the viewpoint of radical mobility, a phenyl group is preferred.
Specific examples of the R ² aralkyl group include a benzyl group, a phenethyl group, and a naphthylmethyl group. Radicals such as a benzyl group and a naphthylmethyl group are preferred because of their unique reactivity.
Examples of the substituent for the aryl ring portion of the aryl group or the aralkyl group of R ² include an alkyl group, a halogen atom, and an alkoxy group, but unsubstituted is preferable from the viewpoint of radical mobility.

<R ³ and n>
R ³ represents a — (CH ₂ ) _n — group. In the case where R ³ is a substituent that can be conjugated with the carbazole ring of formula (1), the conjugation of R ³ is extended from the carbazole ring, resulting in a longer absorption wavelength of the initiator. Therefore, R ³ is preferably a — (CH ₂ ) _n — group that does not have such a conjugated system.
N represents an integer of 1 to 6. Among these, it is preferably 2 or more. Further, it is preferably 4 or less. When n is in the above preferred range, the electronic effect of the substituent R ⁴ substituted on the tip tends to be reflected.

<R ^4>
R ⁴ represents a hydrogen atom or an arbitrary substituent. Arbitrary substituents are not particularly limited as long as they do not impair the effects of the present invention, but include alkyl groups, alkoxycarbonyl groups, monoalkylaminocarbonyl groups, dialkylaminocarbonyl groups, aromatic ring groups, and heterocyclic groups. Can be mentioned.
Among these, R ⁴ is preferably an alkyl group, an alkoxycarbonyl group, an aromatic ring group, or a heterocyclic group from the viewpoint of availability of raw materials and ease of synthesis, and is preferably an alkoxycarbonyl group that is far from electronic. This is particularly preferable from the standpoint of effect.

(R ⁴ alkyl group)
Specific examples of the alkyl group for R ⁴ are the same as those for R ¹ described above, and the substituents that may be present are also the same. Among these, the number of carbon atoms is preferably 1 or more, and preferably 8 or less, more preferably 4 or less, from the viewpoint of adjusting the solubility of the compound.

(Alkoxycarbonyl group R ⁴⁾
Examples of the alkoxycarbonyl group for R ⁴ include a methoxycarbonyl group, an ethoxycarbonyl group, an isopropoxycarbonyl group, and the like. The number of carbon atoms is preferably 2 or more, and preferably 19 or less, more preferably 7 or less. It is preferable from the viewpoint of adjusting the solubility of the compound.
In addition, the alkoxycarbonyl group may have a substituent, and examples of the substituent that may be included include an alkoxy group, a dialkylamino group, and a halogen atom. Among these, an alkoxy group is preferable in terms of ease of adjusting the solubility.

(Monoalkylamino group of R ^4, dialkylaminocarbonyl group)
Specific examples of the alkyl group moiety of the monoalkylaminocarbonyl group and dialkylaminocarbonyl group of R ⁴ have the same meaning as the alkyl group of R ¹ described above, and the substituents that may be present are also synonymous. Among these, carbon number of the alkyl group part couple | bonded with the amino group becomes like this. Preferably it is 1 or more, Preferably it is 8 or less, More preferably, it is 4 or less. When the number of carbon atoms of the alkyl group bonded to the amino group is in the above preferred range, solubility tends to be obtained.

(R ⁴ aromatic ring group)
Examples of the aromatic ring group for R ⁴ include monocyclic or condensed rings such as a phenyl group, a naphthyl group, and an anthryl group. Among these, the number of carbon atoms is 6 or more, and preferably 20 or less, more preferably 10 or less, from the viewpoint of the solubility of the compound.
In addition, the aromatic ring group may have a substituent, and examples of the substituent that may be included include an alkyl group, an alkoxy group, a dialkylamino group, and a halogen atom. Among these, an alkyl group is preferable in terms of ease of adjusting solubility.
Preferred alkyl groups include methyl, ethyl, isopropyl, cyclohexyl, isobutyl, 2-ethylhexyl, n-octyl and the like.

(Heterocyclic group of R ⁴ )
The heterocyclic group for R ⁴ is preferably a group containing at least a heterocyclic structure having one or more heteroatoms in the ring. The hetero atom contained in the heterocyclic group is not particularly limited, and each atom such as S, O, N, and P can be used. From the viewpoint of raw material availability and ease of synthesis, each atom of S, O, and N Is preferred.

  Specific examples include monocyclic or condensed rings such as thienyl, furyl, pyranyl, pyrrolyl, pyridyl, pyrazolyl, thiazolyl, thiadiazolyl, quinolyl, dibenzothiophenyl, benzothiazolyl, and the like. . Among these, the number of carbon atoms is 1 or more, more preferably 2 or more, and preferably 10 or less, more preferably 5 or less, from the viewpoint of raw material availability and ease of synthesis.

In addition, the heterocyclic group may have a substituent, and examples of the substituent that may be included include an alkyl group, an alkoxy group, a dialkylamino group, and a halogen atom. Among these, an alkyl group is preferable in terms of ease of adjusting solubility.
Preferred alkyl groups include methyl, ethyl, isopropyl, cyclohexyl, isobutyl, 2-ethylhexyl, n-octyl and the like.

<R ^5>
R ⁵ represents an arbitrary substituent having no multiple bond conjugated to the carbonyl group to be bonded. By being these groups, the conjugated system does not extend beyond the carbazole ring. Therefore, since the conjugated system of the decomposition artifacts generated after light irradiation does not become long, the absorption wavelength of the decomposition products does not increase. Thereby, the absorption suppression effect after recording is acquired.
Examples of R ⁵ include an alkyl group, an alkoxy group, a dialkylamino group, an alkylsulfonyl group, a dialkylaminosulfonyl group, and the like. Among these, an alkyl group is preferable from the viewpoint of compound stability.

(R ⁵ alkyl group)
Specific examples of the alkyl group for R ⁵ are the same as those for R ¹ described above, and the substituents that may be present are also the same. Among these, the number of carbon atoms is preferably 1 or more, more preferably 2 or more, and preferably 18 or less, more preferably 10 or less, and a branched alkyl group in view of ease of production of the compound. To preferred. Specifically, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, an isopropyl group, a tert-butyl group, an adamantyl group, and a 1-ethylpentyl group are particularly preferable.

(Alkyl moiety of R ⁵ alkoxy group, dialkylamino group, alkylsulfonyl group, dialkylaminosulfonyl group)
Specific examples of the alkyl moiety of the alkoxy group, dialkylamino group, alkylsulfonyl group, and dialkylaminosulfonyl group of R ⁵ are the same as those of R ¹ described above, and the substituents that may be included are also the same. Among these, the number of carbon atoms is preferably 3 or more, and is preferably 18 or less, more preferably 8 or less, from the viewpoint of the crystallinity of the compound.

<Preferable physical properties of the photopolymerization initiator according to the present invention>
The absorption wavelength region of the photopolymerization initiator used in the composition for a hologram recording medium of the present invention is preferably 340 nm or more, more preferably 350 nm or more, and preferably 700 nm or less, more preferably 650 nm or less. It is what has. For example, when the light source is a blue laser, it is preferable to have absorption at least 350 to 430 m, and when the light source is a green laser, it is preferable to have absorption at least 500 to 550 nm. When the absorption wavelength region is different from the above range, the sensitivity tends to be lowered because the irradiated light energy is not easily used for the photopolymerization reaction.

The photopolymerization initiator used in the composition for a hologram recording medium of the present invention preferably has a molar extinction coefficient of 10 L · mol ⁻¹ · cm ⁻¹ or more at the hologram recording wavelength, and is preferably 50 L · mol ⁻¹ ·. More preferably, it is cm ⁻¹ or more. Further preferably at most 20000L ^· mol ^{-1 · cm} -1, more preferably not more than 10000L ^· mol ^{-1 · cm} -1. When the molar extinction coefficient is in the above range, effective recording sensitivity can be obtained, and the transmittance of the medium is prevented from becoming too low, and sufficient diffraction efficiency with respect to the thickness tends to be obtained. .

The solubility of the photopolymerization initiator used in the composition for a hologram recording medium of the present invention is preferably 0.01% or more, more preferably 0.1% or more, in a urethane composition at 25 ° C. and 1 atmosphere. More preferably it is.
Among the commonly used oxime ester-based initiators, those having the above-mentioned absorption maximum are generally based on materials constituting urethane compositions such as isocyanates and polyols, and photoactive compounds such as (meth) acrylic acid esters. Although the solubility is often poor, the photopolymerization initiator represented by the formula (1) used in the present invention is a material constituting a urethane composition such as isocyanates and polyols, and light such as (meth) acrylic acid esters. Since it has excellent solubility in an active compound, it can be used in a composition for a hologram recording medium.

As the photopolymerization initiator used in the composition for a hologram recording medium of the present invention, the photopolymerization initiator represented by the formula (1) can be used alone, but other photopolymerization initiators can be used as necessary. Can also be used in combination.
Other photopolymerization initiators include, for example, acetophenones, benzophenones, hydroxybenzenes, thioxanthones, anthraquinones, ketals, hexaarylbiimidazoles, titanocenes, acylphosphine oxides, halogenated hydrocarbon derivatives Organic boronates, organic peroxides, onium salts, sulfone compounds, carbamic acid derivatives, sulfonamides, triarylmethanols, and the like. Any one of these may be used alone, or two or more may be used in any combination and ratio.

The blending amount of other photopolymerization initiators (the total amount when two or more are combined) is arbitrary as long as it does not impair the function of the photopolymerization initiator of the present invention. ) Is generally 0.001% by weight or more, preferably 0.01% by weight or more, and usually 100% by weight or less, preferably 80% or less, more preferably 50% or less. is there.
Although the specific example of the photoinitiator shown by Formula (1) is shown below, it is not limited to this.

The method for synthesizing the photopolymerization initiator represented by the formula (1) is not particularly limited, and can be produced by a combination of general synthesis methods. Specific examples include the methods described in International Publication No. 2009/131189.
For example, as shown in the following chemical formula, introduction of an acyl group containing R ⁵ , R ⁴ and R ³ into a carbazole ring can be carried out by Friedel-Crafts reaction. For the Friedel-Crafts reaction,
Andrew Streitwieser.Jr. Et.al, Introduction to Organic Chemistry, Macmillan Publishing Company, New York, P652-653,
as well as
Bradford p. Mundy et.al., Name Reactions and Reagents in Organic Synthesis, A Wiley-Interscience Publication, P82-83
Etc. are described.

Nitrosation to methylene is possible by a method using nitrous acid or nitrite.
For the acylation of the hydroxyl group, a method using a corresponding acid halide or anhydride and a base can be used.
For nitosolation and acylation shown in the chemical formula below,
Patent publication 2004-534797,
It is also described in Organic Reaction Volume VII, KRIEGER PUBLISHING COMPANY MALABAR, Florida, Chapter 6, etc.

The above ^R 1 to R ⁵ have the same meanings as ^R 1 to R ⁵ of formula (1).
1-2. Compound having a polymerizable reactive group The compound having a polymerizable reactive group according to the present invention refers to a compound that can be polymerized by the photopolymerization initiator. The kind of the compound having a polymerizable reactive group 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 compound having a polymerizable reactive group 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, which will be described later, hardly inhibit the reaction forming the resin matrix.

<Cationically polymerizable monomer>
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, ethylenically unsaturated bond compounds, cyclic ether compounds. , Cyclic thioether compounds, vinyl compounds and the like. 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 anionic polymerizable monomers 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.

<Radically 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.
The compound having a polymerizable reactive group used in the composition for a hologram recording medium of the present invention preferably has a molecular weight of 80 or more, more preferably 150 or more, more preferably 300 or more, and particularly preferably 400 or more. Moreover, it is preferably 3000 or less, more preferably 2500 or less, more preferably 2000 or less. When the molecular weight is equal to or more than the above lower limit value, the shrinkage rate of the recording layer accompanying polymerization of light irradiation at the time of hologram information recording tends to be reduced. Further, when the molecular weight is not more than the above upper limit, the mobility of the compound having a polymerizable reactive group in the recording layer using the composition for a hologram recording medium is high, diffusion easily occurs, and sufficient diffraction efficiency is achieved. Tend to be able to get.

  The compound having a polymerizable reactive group used in the composition for a hologram recording medium of the present invention preferably has a refractive index of 1.50 or more, more preferably 1.52 at the wavelength of light irradiated to the hologram recording medium (recording wavelength, etc.). More preferably, it is 1.55 or more. If the refractive index is large, sufficient diffraction efficiency can be obtained and the multiplicity can be improved. In many cases, the refractive index in the visible light region shows a large value when evaluated at a short wavelength, but a sample showing a relatively large refractive index at a short wavelength shows a relatively large refractive index even at a long wavelength. It is also possible to evaluate the refractive index at a wavelength other than the recording wavelength and predict the refractive index at the recording wavelength.

The compound having a polymerizable reactive group used in the composition for a hologram recording medium of the present invention preferably has a molar extinction coefficient at a recording wavelength of the hologram of 100 L · mol ⁻¹ · cm ⁻¹ or less. When the molar extinction coefficient is 100 L · mol ⁻¹ · cm ⁻¹ or less, the transmittance of the medium is prevented from being lowered, and sufficient diffraction efficiency with respect to the thickness tends to be obtained.

Among the compounds having a polymerizable reactive group used in the composition for a hologram recording medium of the present invention, a compound having a halogen atom (iodine, chlorine, bromine, etc.) in the molecule as a compound having a polymerizable reactive group having a particularly high refractive index And compounds having heteroatoms (nitrogen, sulfur, oxygen, etc.) are preferred.
A compound having an aromatic ring structure or a quaternary carbon is also preferable. The aromatic ring structure is more preferably a condensed ring structure.

Moreover, the compound which has the structure which combined the above is more preferable. A structure such as an aromatic ring substituted with a halogen atom or a heteroaromatic ring containing nitrogen or sulfur atom is particularly preferred.
The composition for a hologram recording medium of the present invention may contain a compound used for forming a matrix resin of a hologram recording medium in addition to the above-described compound having a polymerizable reactive group and a photopolymerization initiator. . The matrix resin is not particularly limited as long as it can be used for a hologram recording medium. Hereinafter, the matrix resin will be described in detail.

1-3. Matrix resin The composition for a hologram recording medium of the present invention preferably contains a matrix resin. The matrix resin constituting the recording layer of the hologram recording medium is an organic substance that does not change significantly chemically and physically by light irradiation, and is mainly composed of an organic polymer.
The matrix resin is compatible with the polymerizable reactive compound described above, maintains the composition for hologram recording medium in a film shape, and plays a role in adhesion to a support described later. There is a strong demand for excellent compatibility with a reactive compound, a photopolymerization initiator, and the like. If the compatibility between the matrix resin and these components is low, an interface will be created between the materials, and light will be refracted and reflected at the interface. Thus, information is deteriorated by being recorded in an inappropriate part. The compatibility between the matrix resin and the other components is, for example, as described in Japanese Patent No. 3737306, and the scattered light intensity obtained by installing a detector with the transmitted light and angle with respect to the sample. It can be evaluated based on the above.

As a matrix resin of the composition for a hologram recording medium of the present invention, a resin that can be dissolved in a solvent or a resin that is three-dimensionally cross-linked may be used. For example, a thermoplastic resin or a thermosetting resin described below. Examples thereof include resins and photocurable resins.
The three-dimensionally cross-linked resin is insoluble in a solvent and contains a reaction cured product of a polymerizable compound that is liquid at room temperature and a compound that is reactive with the polymerizable compound. Since the three-dimensionally crosslinked resin becomes a physical obstacle, volume change during recording is suppressed. That is, in the recording layer after recording, the bright part expands and the dark part contracts, and the surface of the hologram recording medium becomes uneven. In order to suppress this volume change, it is more preferable to use a three-dimensionally crosslinked resin matrix for the recording layer.
Among these, from the viewpoint of compatibility and adhesion to the substrate, the matrix resin is preferably a thermosetting resin, and among them, a polyurethane resin obtained by a reaction between an isocyanate and a polyol is preferable.

1-3-1. Thermoplastic Resin When a thermoplastic resin is used as the matrix resin, the recording layer of the hologram recording medium can be formed by a thermal processing step such as pressing or injection molding after all the materials are mixed and uniformly dispersed. At this time, since it is necessary to melt the resin with heat, a high temperature is generally required, and there is a concern about deterioration of the polymerizable reactive compound.

  In addition, the solution is supplied to the substrate after being dissolved in a solvent, the thickness is adjusted by rotating or mechanical leveling, and after removing the solvent, another substrate is laminated and laminated to form a recording layer of the hologram recording medium. It can also be formed. Alternatively, after forming on a different substrate as described above, it can be peeled off from the substrate, transferred onto another substrate, and pasted together with another substrate. In any case, it is necessary to remove the solvent, and it is difficult to form a thick film by a single operation, and a plurality of operations are required.

  Examples of specific materials for thermoplastic resins include chlorinated polyethylene, polymethyl methacrylate resin (PMMA), copolymers of methyl methacrylate and other alkyl acrylates, copolymers of vinyl chloride and acrylonitrile, Examples thereof include cellulose resins such as polyvinyl acetate resin (PVAC), polyvinyl alcohol, polyvinyl formal, polyvinyl pyrrolidone, ethyl cellulose and nitrocellulose, polystyrene resin, and polycarbonate resin. These may be used alone or in combination of two or more.

The solvent for these thermoplastic resins is not particularly limited as long as it dissolves them, but ketones such as acetone and methyl ethyl ketone, esters such as butyl acetate and propylene glycol methyl ether acetate, aromatic hydrocarbons such as toluene and xylene, Examples include ethers such as tetrahydrofuran and 1,2-dimethoxyethane, and amides such as N, N-dimethylacetamide and N-methylpyrrolidone.
Moreover, these may use only 1 type and may mix and use 2 or more types.

1-3-2. Thermosetting resin When a thermosetting resin is used as the matrix resin, the curing temperature varies depending on the type of crosslinking agent and catalyst.
Representative examples of combinations of functional groups that cure at room temperature are epoxy and amine, epoxy and thiol, and isocyanate and amine. Typical examples of using the catalyst are epoxy and phenol, epoxy and acid anhydride, and isocyanate and polyol.

The former is convenient because it reacts immediately when mixed, but it is difficult to adjust because there is no time allowance when it is shaped like a medium. On the other hand, the latter is suitable for curing with molding such as an optical medium because the curing temperature and curing time can be freely selected by appropriately selecting the type and amount of the catalyst. These are commercially available from low molecular weight to high molecular weight and various types of resin raw materials, and can be selected while maintaining compatibility with polymerizable reactive compounds and catalysts, adhesion to the support, and the like.
Although each raw material is demonstrated below, each raw material may be used individually by 1 type and may use 2 or more types together.

<Epoxy>
Examples of the epoxy include polyglycidyl ether compounds of polyols such as (poly) ethylene glycol, (poly) propylene glycol, (poly) tetramethylene glycol, trimethylolpropane, glycerin, 3,4-epoxycyclohexylmethyl-3,4-epoxy. Cycloaliphatic carboxylates, 3,4-epoxy-1-methylcyclohexyl-3,4-epoxy-1-methylhexanecarboxylates and other alicyclic epoxy compounds having a 4-7 membered cyclic aliphatic group, bisphenol A type Examples include epoxy compounds, hydrogenated bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, phenol or cresol novolac type epoxy compounds.

  The epoxy preferably has two or more epoxy groups in one molecule, but the type is not particularly limited. If the number of epoxy groups is small, the hardness required for the matrix may not be obtained. The upper limit of the number of epoxy groups in one molecule is not particularly limited, but is usually 8 or less, preferably 4 or less. If the number of epoxy groups is too large, it takes a long time to consume the epoxy groups and it may take too long to form the matrix resin.

<Amine>
As the amine, one containing a primary amine group or a secondary amine group can be used. Examples of such amines include aliphatic polyamines such as ethylenediamine, diethylenetriamine and derivatives thereof, alicyclic polyamines such as isophoronediamine, menthanediamine, N-aminoethylpiperazine and derivatives thereof, and m-xylylenediamine. , Aromatic polyamines such as diaminodiphenylmethane and derivatives thereof, polyamides such as condensates of dicarboxylic acids such as dimer acid and the above polyamines, imidazole compounds such as 2-methylimidazole and derivatives thereof, and dicyandiamide, adipine And acid dihydrazide.

<Thiol>
As thiols, 1,3-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,2-benzenedithiol, 1,3-benzenedithiol, 1,4-benzenedithiol, 1,10- Dithiols such as decanedithiol, 1,2-ethanedithiol, 1,6-hexanedithiol, 1,9-nonanedithiol, Epomate QX10 (manufactured by Japan Epoxy Resin Co., Ltd.), Epomate QX11 (manufactured by Japan Epoxy Resin Co., Ltd.) Examples include thiol compounds such as polythiol (Toray Fine Chemical Co., Ltd.), Cup Cure 3-800 (Japan Epoxy Resin Co., Ltd.), and EpiCure QX40 (Japan Epoxy Resin Co., Ltd.). Among these, commercially available fast-curing polythiols such as Epomate QX10, Epomate QX11, Cup Cure 3-800, EpiCure QX40, etc. are preferably used.

<Phenol>
Examples of the phenol include bisphenol A, a novolac type phenol resin, and a resol type phenol resin.

<Acid anhydride>
Examples of acid anhydrides include monofunctional acid anhydrides such as phthalic anhydride, tetrahydrophthalic anhydride, and derivatives thereof, and bifunctional acid anhydrides such as pyromellitic anhydride, benzophenone tetracarboxylic anhydride, and the like. Derivatives and the like.

<Amounts of amine, thiol, phenol and acid anhydride>
The amount of amine, thiol, phenol, and acid anhydride used is a ratio with respect to the number of moles of the epoxy group, usually 0.1 equivalents or more, especially 0.7 equivalents or more, and usually 2.0 equivalents or less, especially 1.5. The range below the equivalent is preferable. If the amount of amine, thiol, phenol, or acid anhydride used is too small or too large, the number of unreacted functional groups may be large and storage stability may be impaired.

<Polymerization initiator as catalyst>
As the catalyst, an anionic polymerization initiator and a cationic polymerization initiator can be used depending on the curing temperature and the curing time.
An anionic polymerization initiator generates an anion by irradiation with heat or active energy rays, and examples thereof 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, Examples include imidazole compounds such as 2-ethyl-4-methylimidazole, and derivatives thereof. You may use 1 type or multiple types according to hardening temperature and hardening time.

The cationic polymerization initiator generates cations by irradiation with heat or active energy rays, and examples thereof 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. You may use 1 type or multiple types according to hardening temperature and hardening time.

  The amount of these initiators used is preferably in the range of usually 0.001% by weight or more, particularly 0.01% by weight or more, and usually 50% by weight or less, especially 10% by weight or less based on the matrix resin. If the amount of these initiators used is too small, the concentration of the initiator is too low, and thus the polymerization reaction may take too long. On the other hand, if the amount of initiator used is excessively large, a continuous ring-opening reaction may not occur as a polymerization reaction.

<Isocyanate>
As the isocyanate, those having two or more isocyanate groups in one molecule are preferable, but the kind thereof is not particularly limited. If the number of isocyanate groups in one molecule is small, the hardness required for the matrix resin may not be obtained. The upper limit of the number of isocyanate groups in one molecule is not particularly limited, but is usually 8 or less, preferably 4 or less. If the number of isocyanate groups in one molecule is too large, it may take a long time to consume the isocyanate groups and may take too much time to form the matrix resin. The type is not particularly limited as long as it has two or more isocyanate groups in one molecule. The upper limit of the number of isocyanate groups in one molecule is not particularly limited, but is usually about 20 or less.

  Examples of the isocyanate used in the present embodiment include aliphatic isocyanates such as hexamethylene diisocyanate, lysine methyl ester diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4′-methylenebis (cyclohexyl isocyanate). ), Etc .; aromatic diisocyanates such as tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, naphthalene-1,5′-diisocyanate; and multimers thereof. ˜7-mer is preferred.

In addition to these, there can be mentioned, for example, a reaction product of polyhydric alcohols such as water, trimethylolethane, trimethylolpropane and the above-mentioned isocyanates, a multimer of hexamethylene diisocyanate, or a derivative thereof.
The molecular weight of the isocyanate used in the present embodiment is preferably a number average molecular weight of 100 or more and 50000 or less, more preferably 150 or more and 10,000 or less, and further preferably 150 or more and 5000 or less. If the number average molecular weight is excessively small, the crosslink density increases, so that the hardness of the matrix resin becomes too high, and the recording speed may decrease. On the other hand, if the number average molecular weight is excessively large, the compatibility with other components may be reduced or the crosslink density may be lowered, so that the hardness of the matrix resin becomes too low and the recorded content may be lost.

<Polyol>
A polyol is mentioned as a compound which has an isocyanate reactive functional group based on this invention.
Examples of the polyol include polypropylene polyol, polycaprolactone polyol, polyester polyol, and polycarbonate polyol.

(Polypropylene polyol)
Polypropylene polyol is obtained by reaction of propylene oxide with diol or polyhydric alcohol. Examples of the diol or polyhydric alcohol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, and neopentyl. Examples include glycol, diethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, decamethylene glycol, polyethylene glycol, and polytetramethylene glycol. Examples of commercially available polypropylene polyols include Newpol GP400 and GP1000 (both manufactured by Sanyo Kasei Co., Ltd., trade names), Adeka Polyether G400, G700, and G1500 (both manufactured by Adeka Co., Ltd.).

(Polycaprolactone polyol)
The polycaprolactone polyol is obtained by reacting a lactone with a diol or a polyhydric alcohol. Examples of the lactone include α-caprolactone, β-caprolactone, γ-caprolactone, ε-caprolactone, α-methyl-ε-caprolactone, β-methyl-ε-caprolactone, and the like.

Examples of the diol or polyhydric alcohol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-
Examples include pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, decamethylene glycol, polyethylene glycol, and polytetramethylene glycol.

  Among the commercially available polycaprolactone polyols obtained from the reaction of ε-caprolactone, Plaxel 205, Plaxel 210, Plaxel 220, Plaxel 230, Plaxel 240, Plaxel 303, Plaxel 305, Plaxel 308, Plaxel 312, Plaxel 320 (both Are also available from Daicel Chemical Industries, Ltd.

(Polyester polyol)
Examples of polyester polyols include those obtained by polycondensation of dicarboxylic acids or their anhydrides with polyols.
Examples of the dicarboxylic acid include succinic acid, adipic acid, sebacic acid, azelaic acid, dimer acid, maleic anhydride, isophthalic acid, terephthalic acid, trimellitic acid, and the like.

  Examples of the polyol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, Examples include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, decamethylene glycol, polyethylene glycol, and polytetramethylene glycol.

  Examples of such polyester polyols include polyethylene adipate, polybutylene adipate, and polyhexamethylene adipate. Among those commercially available as polyester polyols, Adeka New Ace F series, Adeka New Ace Y series, Adeka New Ace NS series (trade name, manufactured by Adeka Corporation), Kuraray Polyol N-2010, P-4011, P- C-1000, C-1066, U-21, U-24, U-53, U-253, U-502, U-118A (all Mitsui Chemicals) Polyurethane Co., Ltd., trade name).

(Polycarbonate polyol)
Polycarbonate polyols include those obtained by dealcoholization condensation reaction between glycols and dialkyl carbonates (eg, dimethyl carbonate, diethyl carbonate, etc.), those obtained by dephenol condensation reaction between glycols and diphenyl carbonates, glycols And those obtained by a deglycolization condensation reaction between the salt and carbonates (for example, ethylene carbonate, diethyl carbonate, etc.).

Examples of glycols include aliphatic diols such as 1,6-hexanediol, diethylene glycol, propylene glycol, 1,4-butanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, or 1,4 -Alicyclic diols such as cyclohexanediol and 1,4-cyclohexanedimethanol.
For example, poly (hexamethylene carbonate) polyol obtained by condensation reaction of 1,6-hexanediol and diethyl carbonate, poly (pentylene carbonate) obtained by condensation reaction of pentanediol and diethyl carbonate, 1,4-butane Examples include poly (butylene carbonate) obtained by a condensation reaction between a diol and diethyl carbonate.

  Among those commercially available as polycarbonate polyols, Plaxel CD CD205, Plaxel CD CD210, Plaxel CD CD220 (all trade names manufactured by Daicel Chemical Industries, Ltd.), etc., PCDL T5651, PCDL T5652, PCDL T5650J (all Asahi Kasei Corporation) Product name).

(Molecular weight of polyol)
The molecular weight of the polyol described above is preferably from 100 to 50,000 in terms of number average molecular weight, more preferably from 150 to 10,000, and still more preferably from 150 to 5,000. If the number average molecular weight is excessively small, the crosslink density increases, so that the hardness of the matrix resin becomes too high, and the recording speed may decrease. On the other hand, if the number average molecular weight is excessively large, the compatibility with other components may be reduced or the crosslink density may be lowered, so that the hardness of the matrix resin becomes too low and the recorded content may be lost.

<Other ingredients>
The matrix resin in the present embodiment may contain other components in addition to the above-described components as long as it does not contradict the gist of the present invention.
Examples of such other components include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5- and the like used for the purpose of changing the physical properties of the matrix resin. Hydroxyl groups such as pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, decamethylene glycol, trimethylolpropane, polyethylene glycol, polytetramethylene glycol The compound which has is mentioned.

<Catalyst>
Furthermore, in order to accelerate | stimulate reaction of the compound which has an isocyanate group, and the compound which has an isocyanate reactive functional group, the suitable catalyst may be included. Examples of such catalysts include bis (4-t-butylphenyl) iodonium perfluoro-1-butanesulfonic acid, bis (4-t-butylphenyl) iodonium p-toluenesulfonic acid, bis (4-t-butyl) Phenyl) iodonium trifluoromethanesulfonic acid, (4-bromophenyl) diphenylsulfonium triflate, (4-t-butylphenyl) diphenylsulfonium trifluoromethanesulfonic acid, diphenyliodonium perfluoro-1-butanesulfonic acid, (4- Fluorophenyl) diphenylsulfonium trifluoromethanesulfonic acid, diphenyl-4-methylphenylsulfonium trifluoromethanesulfonic acid, triphenylsulfonium trifluoromethanesulfonic acid, bis (alkylphenyl)
Catalysts based on Lewis acids such as onium salts such as iodonium hexafluorophosphonic acid, zinc chloride, tin chloride, iron chloride, aluminum chloride, BF ₃ , hydrochloric acid, phosphoric acid,
Protonic acids such as trimethylamine, triethylamine, triethylenediamine, dimethylbenzylamine, diazabicycloundecene, etc., 2-methylimidazole, 2-ethyl-4-methylimidazole, trimellitic acid 1-cyanoethyl-2-undecyl Imidazoles such as imidazolylum, bases such as sodium hydroxide, potassium hydroxide, potassium carbonate, dibutyltin laurate, dioctyltin laurate,
Tin catalysts such as dibutyltin octoate, bismuth catalysts such as tris (2-ethylhexanato) bismuth, tribenzoyloxybismuth, tetrakis (ethylacetoacetate) zirconium, 1,1′-isopropylidenezirconocene dichloride, tetrakis (2,4 -Pentandionato) Zirconium catalysts such as zirconium, and the like.

Of these, a bismuth catalyst and a zirconium catalyst are preferable for improving storage stability.
The bismuth-based catalyst is not particularly limited as long as it is a catalyst containing a bismuth element and promotes the reaction of a compound having an isocyanate group and a compound having an isocyanate-reactive functional group.
Examples of bismuth catalysts include tris (2-ethylhexanato) bismuth, tribenzoyloxybismuth, bismuth triacetate, bismuth tris (dimethyldiocarbamate), bismuth hydroxide, triphenylbismuth (V) bis (trichloroacetate) ), Tris (4-methylphenyl) oxobismuth (V), triphenylbis (3-chlorobenzoyloxy) bismuth (V), and the like.

Among these, 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.

The zirconium-based catalyst is not particularly limited as long as it is a catalyst containing a zirconium element and promotes the reaction of a compound having an isocyanate group and a compound having an isocyanate-reactive functional group.
Examples include cyclopentadienylzirconium trichloride, decamethylzirconocene dichloride, 1,1′-dibutylzirconocene dichloride, 1,1′-isopropylidenezirconocene dichloride, tetrakis (2,4-pentanedionato) zirconium, tetrakis ( Trifluoro-2,4-pentanedionato) zirconium, tetrakis (hexafluoro-2,4-pentanedionato) zirconium, zirconium butoxide, zirconium-t-butoxide, zirconium propoxide, zirconium isopropoxide, zirconium ethoxide, bis ( Ethyl acetoacetate) dibutoxyzirconium, tetrakis (ethylacetoacetate) zirconium, zirconium oxide, barium zirconium oxide, calcium oxide di Koniumu, zirconium bromide, zirconium chloride, zirconium fluoride, 2 chloride (indenyl) zirconium, and the like zirconium carbonate is.

Among them, a compound having an organic ligand is preferable from the aspect of compatibility with other components, and more preferable than a compound having an alkoxide or acetylacetonate (2,4-pentanedionate) structure. Any one of the above zirconium compounds may be used alone, or two or more thereof may be used in any combination and ratio.
The bismuth-based catalyst and the zirconium-based catalyst may be used alone or in combination.

The amount of the catalyst used is usually in the range of 0.0001% by weight or more, especially 0.001% by weight or more, and usually 10% by weight or less, especially 5% by weight or less, as a ratio to the matrix resin. If the amount of catalyst used is too small, curing may take too long. On the other hand, if the amount used is excessively large, it may be difficult to control the curing reaction.
Although it can be cured at room temperature by using a catalyst, it may be cured by applying a temperature. The temperature at this time is preferably between 40 ° C and 90 ° C.

1-3-3. Photocurable resin When using a photocurable resin as a matrix resin, it is necessary to harden using the photoinitiator for matrix resins according to the wavelength to be used. Since curing during light irradiation causes problems in molding and adhesion, it is desirable that the curing reaction be stable at around room temperature, which is mainly the temperature at which work is performed. In view of this, it can be said that catalytic curing with a photoinitiator for matrix resin is a desirable choice.

In general, an active substrate of either a cation or an anion is generated by light irradiation from a photoinitiator for a matrix resin. Therefore, it is considered to be good to select those that cause curing by these active substrates and cure them to form a matrix resin.
Examples of functional groups that react with cations such as protons include epoxy groups and oxetanyl groups. Specifically, compounds having these include polyglycidyl ether compounds of polyols such as (poly) ethylene glycol, (poly) propylene glycol, (poly) tetramethylene glycol, trimethylolpropane, glycerin and the like having an epoxy group, 3 , 4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-1-methylcyclohexyl-3,4-epoxy-1-methylhexanecarboxylate, etc. Examples include alicyclic epoxy compounds having a group, bisphenol A type epoxy compounds, hydrogenated bisphenol A type epoxy compounds, bisphenol F type epoxy compounds, phenol or cresol novolac type epoxy compounds. Examples of those having an oxetanyl group include 2-ethyl-2-oxetanyl ether of bisphenol A, 1,6-bis (2-ethyl-2-oxetanyloxy) hexane, and the like. (Here, “(poly) ethylene glycol” and the like refer to both “ethylene glycol” and its polymer “polyethylene glycol”.)

Examples of functional groups that react with anions include epoxy groups and episulfide groups. Specific examples of the compound having an episulfide group include phenyl episulfide and diepisulfide methyl ether of bisphenol A.
The amount of the photoinitiator for the matrix resin used in the case of photocuring the matrix resin described above is usually 0.01% by weight or more, particularly 0.1% by weight or more, and usually, in a ratio to the polymerizable compound. The range of 1% by weight or less, particularly 30% by weight or less is preferable. If the amount of the photoinitiator for matrix resin used is too small, it may take too long to cure. On the other hand, if the amount used is excessively large, it may be difficult to control the curing reaction.
Further, since light is irradiated also during recording, it is important that the wavelength at which the curing is performed is different from the wavelength at which the recording is performed, and the difference in wavelength is at least 10 nm, preferably 30 nm. The selection of the photoinitiator for the matrix resin can be generally predicted from the absorption wavelength of the initiator.

1-4. Other Components The composition for a hologram recording medium of the present invention may contain other components in addition to the above-described components as long as it does not contradict the gist of the present invention.
Other components include a chain transfer agent for controlling the reaction of the recording, such as a solvent, a plasticizer, a dispersant, a leveling agent, an antifoaming agent, and an adhesion promoter, for preparing a recording layer of a hologram recording medium. Examples of other additives that may be required for improving properties such as a polymerization terminator, a compatibilizer, a reaction aid, and a sensitizer include preservatives, stabilizers, antioxidants, ultraviolet absorbers, 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.

<Sensitizer>
A compound that controls excitation of the photopolymerization initiator can be added. Examples of this case include sensitizers and sensitization aids.
As a sensitizer, any one of various known sensitizers can be selected and used. Generally, as a sensitizer, a dye is used to absorb visible and ultraviolet laser beams. In many cases, a colored compound such as is used. Depending on the wavelength of the laser beam used for recording and the type of initiator used, in the case of a system using a green laser, specific examples of preferred sensitizers are JP-A-5-241338 and JP-A-2-2. In the case where the compound described in Japanese Patent Publication No. 69, Japanese Patent Publication No. 2-55446 is a system using a blue laser, it is described in Japanese Patent Application Laid-Open No. 2000-10277, Japanese Patent Application Laid-Open No. 2004-198446, and the like. Compounds. Any one of the various sensitizers exemplified above may be used alone, or two or more may be used in any combination and ratio.

  When the obtained hologram recording medium is required to be colorless and transparent, it is preferable to use a cyanine dye as a sensitizer. In other words, since cyanine dyes are generally easily decomposed by light, the cyanine dyes in the hologram recording medium are decomposed by post-exposure, that is, by leaving them for several hours to several days under room light or sunlight. Thus, there is no absorption in the visible range, and a colorless and transparent hologram recording medium is obtained.

  The amount of the sensitizer needs to be increased or decreased depending on the thickness of the recording layer to be formed, but is usually 0.01% by weight or more, particularly 0.1% by weight or more, and usually by the ratio to the photopolymerization initiator. It is preferably 10% by weight or less, more preferably 5% by weight or less. If the amount of the sensitizer used is too small, the starting efficiency is lowered, and recording may take a long time. On the other hand, if the amount of the sensitizer used is too large, the absorption of light used for recording and reproduction increases, which may make it difficult for light to reach the depth direction. When two or more sensitizers are used in combination, the total amount thereof satisfies the above range.

<Plasticizer>
A plasticizer for improving reaction efficiency and adjusting physical properties of the recording layer can be used.
Examples of plasticizers include dioctyl phthalate, diisononyl phthalate, diisodecyl phthalate, diundecyl phthalate, bis (2-ethylhexyl) adipate, diisononyl adipate, di-n-butyl adipate, etc. Adipates, dioctyl sebacate, sebacates such as dibutyl sebacate, phosphates such as tricresyl phosphate, citrates such as acetyl tributyl citrate, trimellitic acids such as trioctyl trimellitic acid Esters, epoxidized soybean oil, chlorinated paraffin, alkoxylated (poly) alkylene glycol esters such as acetoxymethoxypropane, terminal alkoxylated polyalkylene glycols such as dimethoxypolyethylene glycol, etc. It is below.

  These plasticizers are generally used in a range of from 0.01% by weight to 50% by weight, preferably from 0.05% by weight to 20% by weight, based on the total solid content of the hologram recording medium composition. If the amount of these plasticizers is less than this, the effect on improving the reaction efficiency and adjusting the physical properties will not be exhibited, and if it is more than this amount, the transparency of the recording layer will be lowered or the bleedout of the plasticizer will be noticeable. It is not preferable.

<Leveling agent>
Leveling agents can be used. 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.

<Chain transfer agent>
Chain transfer agents can be used. Chain transfer agents include phosphinates such as sodium phosphite and sodium hypophosphite, mercaptans such as mercaptoacetic acid, mercaptopropionic acid, 2-propanethiol, 2-mercaptoethanol and thiophenol, acetaldehyde, propionaldehyde, etc. Aldehydes, ketones such as acetone and methyl ethyl ketone, halogenated hydrocarbons such as trichloroethylene and perchloroethylene, terpenes such as terpinolene, α-terpinene, β-terpinene and γ-terpinene, 1,4-
Cyclohexadiene, 1,4-cycloheptadiene, 1,4-cyclooctadiene, 1,4-heptadiene, 1,4-hexadiene, 2-methyl-1,4-pentadiene, 3,6-nonanedien-1-ol Non-conjugated dienes such as 9,12-octadecadienol, linolenic acid such as linolenic acid, γ-linolenic acid, methyl linolenic acid, ethyl linolenic acid, isopropyl linolenic acid, linolenic anhydride, linoleic acid, linoleic acid Examples thereof include linoleic acids such as methyl, ethyl linoleate, isopropyl linoleate and linoleic anhydride, eicosapentaenoic acids such as eicosapentaenoic acid and ethyl eicosapentaenoate, docosahexaenoic acids such as docosahexaenoic acid and ethyl docosahexaenoate, and the like.

  The amount of these additives used is usually 0.001% by weight or more, particularly 0.01% by weight or more, and usually 30% by weight, based on the total solid content of the hologram recording medium composition of the present embodiment. In the following, it is preferable that the range be 10% by weight or less. When two or more additives are used in combination, the total amount thereof satisfies the above range.

1-5. 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 proportion of each component shown below is preferably in the following range based on the total mass of the composition for a hologram recording medium.
The amount of the compound having a polymerizable reactive group is preferably 0.1% by mass or more, more preferably 1% by mass or more, and more preferably 2% by mass or more. Moreover, it is 80 mass% or less preferably, More preferably, it is 50 mass% or less, More preferably, it is 30 mass% or less. When the amount of the compound having a polymerizable reactive group is larger than the lower limit, sufficient diffraction efficiency can be obtained in the hologram recording medium, and when the amount is lower than the upper limit, compatibility with the resin matrix in the recording layer is maintained. Therefore, the shrinkage of the recording layer due to recording tends to be kept low.

The amount of the photopolymerization initiator used is preferably 0.001% by mass or more, more preferably 0.01% by mass or more, and preferably 5% by mass or less, more preferably 3% by mass or less. When the amount of the photopolymerization initiator containing the compound represented by the formula (1) of the present invention is in an appropriate range, sufficient recording sensitivity tends to be obtained in the hologram recording medium.
The total amount of materials used for constituting the matrix is usually 0.1% by mass or more, preferably 10% by mass or more, and more preferably 35% by mass or more. Moreover, it is 99.9 mass% or less normally, Preferably it is 99 mass% or less. By making this usage amount equal to or more than the above lower limit value, it becomes easy to form the recording layer.

When a matrix is formed by condensing two types of functional groups, the ratio of the number of reactive functional groups is preferably 0.1 or more, more preferably 0.5 or more. Moreover, it is 10.0 or less normally, Preferably it is 2.0 or less. When this ratio is within the above range, there are few unreacted functional groups, and storage stability is improved.
In the present invention, when a matrix is formed by condensing two types of functional groups, the amount of the catalyst involved in the condensation reaction is preferably determined in consideration of the reaction rate between the functional groups used, preferably 5 It is not more than mass%, more preferably not more than 4 mass%, more preferably not more than 1 mass%. Moreover, it is preferable to use 0.005 mass% or more.
The total amount of other components other than the above components may be 30% by mass or less, preferably 15% by mass or less, and more preferably 5% by mass.

1-6. Composition for hologram recording medium and method for producing hologram recording medium In the present invention, the method for producing a composition for hologram recording medium containing a compound having a polymerizable reactive group and a photopolymerization initiator is not particularly limited, and the order of mixing is not limited. Etc. can be adjusted as appropriate. Moreover, when the composition for hologram recording media contains components other than those described above, the components may be mixed in any combination and order.

The composition for a hologram recording medium of the present invention can be obtained, for example, by the following method, but the present invention is not limited to this.
In addition to the compound having a polymerizable reactive group and a photopolymerization initiator, all components other than the compound having an isocyanate-reactive functional group and the catalyst are mixed to obtain a composition for hologram recording medium (liquid A). A mixture of a compound having an isocyanate-reactive functional group and a catalyst is designated as B liquid. Each liquid is preferably dehydrated and degassed.

Alternatively, a compound having a polymerizable reactive group,-BR> Y and a photopolymerization initiator can be mixed with all components other than a compound having an isocyanate group to form a composition for a hologram recording medium (liquid A). .
If the dehydration and deaeration is insufficient, bubbles may be generated during production of the medium, and a uniform recording layer may not be obtained. In the dehydration / deaeration, heating and decompression may be performed as long as each component is not impaired.

  The production of the composition for a hologram recording medium in which the liquid A and the liquid B are mixed is preferably performed immediately before forming the hologram recording medium. At this time, it is also possible to use a mixing technique by a conventional method. Further, at the time of mixing the liquid A and the liquid B, deaeration may be performed as necessary in order 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.

  Moreover, the isocyanate functional prepolymer by reaction of the compound which has an excess isocyanate group, and the compound which has an isocyanate reactive functional group can also be used as a compound which has an isocyanate group. Furthermore, an isocyanate-reactive prepolymer obtained by reacting a compound having an excess isocyanate-reactive functional group with a compound having an isocyanate group can also be used as the compound having an isocyanate-reactive functional group.

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 hologram recording 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.

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 later in the section of the recording method, a compound having a polymerizable reactive group contained in the recording layer (hereinafter referred to as a polymerizable monomer) partially undergoes a chemical change such as polymerization due to hologram recording or the like. It will occur. 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, but is preferably 1 μm or more, more preferably 10 μm or more, and preferably 1 cm or less, more preferably 3 mm or less. It is. By setting the thickness of the recording layer to be equal to or more than the above lower limit value, the selectivity of each hologram is increased at the time of multiplex recording on the hologram recording medium, and the degree of multiplex recording tends to be increased. Further, by making the thickness of the recording layer equal to or less than the above upper limit value, the entire recording layer can be formed uniformly, and multiplex recording with uniform diffraction efficiency of each hologram and high S / N ratio is performed. There is a tendency to be able to.
In addition, the shrinkage ratio of the recording layer due to exposure during recording and reproduction of information is preferably 0.25% or less from the viewpoint of recording reproducibility.

2-2. Support As long as the support has the strength and durability required for the hologram recording medium, the details thereof are not particularly limited, 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 acrylic, polyethylene terephthalate, polyethylene naphthoate, polycarbonate, polyethylene, polypropylene, amorphous polyolefin, polystyrene, polycycloolefin, cellulose acetate, and other organic materials; glass, silicon, quartz, etc. An inorganic material is mentioned. Among these, polycarbonate, acrylic, polyester, amorphous polyolefin, glass and the like are preferable, and polycarbonate, acrylic, amorphous polyolefin, polycycloolefin, and glass are more preferable.

On the other hand, as an opaque material for the support, a metal such as aluminum, a metal such as gold, silver, and aluminum, or a dielectric such as magnesium fluoride and 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, It is preferable to set it as the range of 0.05 mm or more and 1 mm or less. When the thickness of the support is not less than the above lower limit, the mechanical strength of the hologram recording medium can be obtained, and the warpage of the substrate can be prevented. Further, when the thickness of the support is equal to or less than the above upper limit, advantages such as an increase in the amount of transmitted light and a reduction in the weight and cost of the hologram recording medium can be obtained.

  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 include a reflective coating process for forming a reflective coating layer made of a metal such as gold, silver, or aluminum, or a dielectric coating process for forming a dielectric layer such as magnesium fluoride or zirconium oxide. Can be mentioned. 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 hologram recording medium can be 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 (information light, reference light, reproduction light, etc.). In the present invention, being transparent means that the transmittance of information light in the wavelength region is 50% or more, preferably 80% or more.

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 deterioration of recording / reproducing characteristics. 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 is provided on the side on which information light, reference light and reproduction light are incident and emitted, or between the recording layer and the support. Also good. The antireflection film functions to improve the light utilization efficiency and suppress the generation of noise.
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, a doctor roll coat method, and the like. 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 the solvent to be used, Usually, it is preferable to use what has sufficient solubility with respect to a use component, gives favorable coatability, and does not attack support bodies, such as a resin substrate. 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, from the viewpoint of coating efficiency and handleability, it is preferable to prepare a coating solution having a solid content concentration of about 1% to 100% by weight.

Examples of solvents include ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and methyl amyl ketone; aromatic solvents such as toluene and xylene; methanol, ethanol, propanol, n-butanol, heptanol, hexanol, Alcohol solvents such as diacetone alcohol and furfuryl alcohol; ketone alcohol solvents such as diacetone alcohol and 3-hydroxy-3-methyl-2-butanone; ether solvents such as tetrahydrofuran and dioxane; dichloromethane, dichloroethane and chloroform Halogen solvents of: Cellosolve solvents such as methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl cellosolve acetate, ethyl cellosolve acetate; Propylene glycol solvents such as methyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monobutyl ether acetate, dipropylene glycol dimethyl ether; ethyl acetate, butyl acetate, Amyl acetate, butyl acetate, ethylene glycol diacetate, diethyl oxalate, ethyl pyruvate, ethyl-2-hydroxybutyrate ethyl acetoacetate, methyl lactate, ethyl lactate, methyl 2-hydroxyisobutyrate, methyl 3-methoxypropionate, etc. Ester solvents: tetrafluoropropanol, octafluoropentanol, hexafluo Perfluoroalkyl alcohol solvents such as butanol; highly polar solvents such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone and dimethylsulfoxide; chain hydrocarbon solvents such as n-hexane and n-octane; cyclohexane, methylcyclohexane, Examples thereof include cyclic hydrocarbon solvents such as ethylcyclohexane, dimethylcyclohexane, n-butylcyclohexane, tert-butylcyclohexane and cyclooctane; or a mixed solvent thereof.

As a method for producing a hologram recording medium, for example, a method for producing a recording layer by applying a composition for a hologram recording medium melted by heat onto a support, cooling and solidifying it, and for a liquid hologram recording medium A method in which a composition is applied to a support and cured by thermal polymerization to form a recording layer, and a liquid hologram recording medium composition is applied to a support and cured by photopolymerization. Examples of the method include manufacturing a 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 recorded and reproduced on the hologram recording medium of the present invention by light irradiation.
For example, when information is recorded as a volume hologram, information light including information to be recorded on the hologram recording medium is irradiated to the recording layer together with the reference light, and the information light and the reference light are crossed in the recording layer. The interference fringes formed by the intensity of the light generated thereby cause polymerization and concentration change of the polymerizable monomer in the recording layer, and as a result, a diffraction grating corresponding to the interference fringes is formed in the recording layer. , Recorded as a hologram in the recording layer.

On the other hand, when reproducing the hologram recorded on the recording layer, the recording layer is irradiated with predetermined reference light. The irradiated reference light is diffracted by the diffraction grating and reproduced as reproduction light. Since the reproduction light is light corresponding to the information light, the information recorded on the recording layer can be reproduced by reading the reproduction light with an appropriate detection means. Note that the wavelength regions of the information light and the reference light are arbitrary depending on the respective use, and may be in the visible light region or the ultraviolet region. Preferable examples as these light sources, for example, ruby, glass, Nd-YAG, Nd-YVO ₄ or the like solid-state laser; GaAs, InGaAs, diode lasers such as GaN, helium - neon, argon, krypton, excimer, CO Gas lasers such as ₂ ; lasers excellent in monochromaticity and directivity, such as dye lasers having pigments.

Further, there is no limitation on the irradiation amount of the information light and the reference light, and the irradiation amount is arbitrary as long as it can be recorded and reproduced. However, if the amount is extremely small, the chemical change of the polymerizable monomer may be insufficient, and the heat resistance and mechanical properties of the recording layer may not be sufficiently expressed. Conversely, if the amount is extremely large, the components of the recording layer ( There is a possibility that the component of the composition for a hologram recording medium of the present invention is photodegraded. Therefore, the information light and the reference light are usually 0 in accordance with the composition of the hologram recording medium composition of the present invention used for forming the recording layer, the type and amount of the photopolymerization initiator, and the like.
. 05J / cm ² or more, irradiated at 20 J / cm ² or less.

  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. Hereinafter, the synthesis method of each compound will be described in detail with an accompanying chemical formula including the synthesis process.
[Example 1]

Compound 1 (3.0 g, 15 mmol) was dissolved in 50 mL of methylene chloride, and compound 2 (2.5 g, 15 mmol) was added at 5 ° C. Further aluminum chloride (2.1 g, 15 mmol) was added in portions to this solution. After completion of the reaction, the reaction solution was poured into ice water and extracted with chloroform. The organic layer was washed with brine and dried over sodium sulfate. After filtration, the solvent was removed under reduced pressure, and the resulting crude product was purified by silica gel chromatography to obtain compound 3.

  Compound 5 was obtained in the same manner as the synthesis method of Compound 3 of Synthesis Example 1 except that Compound 1 was changed to Compound 3 and Compound 2 was changed to Compound 4.

Compound 5 (1.4 g, 3.6 mmol) was dissolved in 23 mL of methylene chloride, and 2M hydrochloric acid ether solution (7.2 mL) was added. The reaction solution was cooled to 5 ° C. and isoamyl nitrite (0.47 g, 4.0 mmol) was added. The reaction mixture was stirred at 5 ° C. until compound 5 disappeared, and then the reaction was stopped by adding water. The mixture was extracted with ethyl acetate, and the organic layer was washed with an aqueous sodium carbonate solution and brine and dried over sodium sulfate. After filtration, the solvent was removed under reduced pressure to obtain Compound 6. The crude product obtained without purification was directly used in the next step.

Compound 6 (1.5 g, 3.6 mmol) was dissolved in 17 mL of methylene chloride, and triethylamine (1.0 mL, 7.2 mmol) was added. Further, Compound 7 (1.1 mL, 5.4 mmol) was added dropwise.
After the addition, the reaction solution was stirred overnight at room temperature. Water was added to the reaction solution to stop the reaction. Extraction with ethyl acetate was performed, and the organic layer was washed with aqueous sodium bicarbonate and dried over sodium sulfate. After filtration, the solvent was removed under reduced pressure, and the resulting crude product was purified by column chromatography to obtain Compound 8 (Example 1).
[Example 2]

  Compound 10 was obtained in the same manner as the synthesis method of Compound 5 of Synthesis Example 1 except that Compound 4 was changed to Compound 9.

  Compound 11 was obtained in the same manner as in the synthesis method of Compound 6 of Synthesis Example 1 except that Compound 5 was changed to Compound 10.

Compound 12 (Example 2) was obtained in the same manner as the synthesis method of Compound 8 of Synthesis Example 1 except that Compound 6 was changed to Compound 11.
[Example 3]

  Compound 14 was obtained in the same manner as the synthesis of Compound 3 of Synthesis Example 1 except that Compound 2 was changed to Compound 13 and aluminum chloride was changed to zinc chloride.

  Compound 15 was obtained in the same manner as the synthesis of Compound 3 of Synthesis Example 1 except that Compound 1 was changed to Compound 14.

  Compound 16 was obtained in the same manner as the synthesis method of Compound 6 of Synthesis Example 1 except that Compound 5 was changed to Compound 15.

Compound 17 (Example 3) was obtained in the same manner as in the synthesis method of Compound 8 of Synthesis Example 1 except that Compound 6 was changed to Compound 16.
[Example 4]

  Compound 19 was obtained in the same manner as the synthesis of Compound 3 of Synthesis Example 1 except that Compound 2 was changed to Compound 18.

  Compound 20 was obtained in the same manner as the synthesis of Compound 3 of Synthesis Example 1 except that Compound 1 was changed to Compound 19.

  Compound 21 was obtained in the same manner as in the synthesis method of Compound 6 of Synthesis Example 1 except that Compound 5 was changed to Compound 20.

Compound 22 (Example 4) was obtained in the same manner as in the synthesis method of Compound 8 of Synthesis Example 1 except that Compound 6 was changed to Compound 21.
[Example 5]

  Compound 24 was obtained in the same manner as in the synthesis method of Compound 20 of Synthesis Example 4 except that Compound 2 was changed to Compound 23.

  Compound 25 was obtained in the same manner as in the synthesis method of Compound 6 of Synthesis Example 1 except that Compound 5 was changed to Compound 24.

Compound 26 (Example 5) was obtained in the same manner as in the synthesis method of Compound 8 of Synthesis Example 1 except that Compound 6 was changed to Compound 25.
[Example 6]

  Compound 28 was obtained in the same manner as the synthesis method of Compound 5 of Synthesis Example 1 except that Compound 4 was changed to Compound 27.

  Compound 29 was obtained in the same manner as in the synthesis method of Compound 6 of Synthesis Example 1 except that Compound 5 was changed to Compound 28.

Compound 30 (Example 6) was obtained in the same manner as in the synthesis method of Compound 8 of Synthesis Example 1 except that Compound 6 was changed to Compound 29.
[Synthesis Example 1]

  Compound 31 was synthesized according to the following scheme according to the description in International Publication No. 2009/131189.

   [Synthesis Example 2]

Compound 32 was synthesized according to the following scheme in the same manner as Compound 31 according to the description in International Publication No. 2009/131189.

[Example 7]
<Preparation of composition for hologram recording medium>
Compound A was dissolved in hexamethylene diisocyanate (isocyanate) as acrylic acid-2,4,6-tribromophenyl ester (polymerizable monomer) and a photopolymerization initiator to prepare solution A.

Next, an octylic acid solution (urethane polymerization catalyst) of tris (2-ethylhexanoate) bismuth was dissolved in polyoxypropylene glycol (polyol) having a molecular weight of about 1000 to prepare a B solution.
Liquid A and Liquid B were each degassed under reduced pressure at 45 ° C. for 2 hours, and then liquid A and liquid B were stirred and mixed, and further degassed in vacuo for several minutes.

<Preparation of measurement sample>
Subsequently, a spacer sheet having a thickness of 1.5 mm and a width of 10 mm is placed on the ends of two opposite sides of 75 mm of a rectangular slide glass of 25 mm × 75 mm, and the above mixed liquid is vacuum degassed between the spacer sheets on the slide glass. Then, another glass slide was placed thereon, the periphery was fixed with a clip, and heated at 80 ° C. for 24 hours to prepare a hologram recording medium for measurement. In this hologram recording medium, a recording layer having a thickness of 1.5 mm is formed between slide glasses as a support. Similarly, a measurement hologram recording medium having a recording layer thickness of 0.5 mm was prepared using a spacer sheet having a thickness of 0.5 mm. In addition, a plurality of hologram recording media having respective recording layer thicknesses were prepared for evaluation of recording performance described later.

[Examples 8 to 12, Comparative Examples 1 and 2]
In Example 7, the hologram recording media of Examples 8 to 12 and Comparative Examples 1 and 2 were produced in the same manner except that the compound used as the photopolymerization initiator and the content thereof were changed. Table 1 shows the photopolymerization initiator used in each Example and Comparative Example, and the weight content of each material in the composition for hologram recording medium.

[Hologram recording and evaluation method]
Using the hologram recording media of the above-described examples and comparative examples, the hologram recording performance was evaluated according to the procedure described below.
The incident angle to the hologram recording medium was 61 multiple recordings at the same location from -30 ° to 30 ° every other 1 °, and the sum of the square roots of diffraction efficiency at that time was M / # (M number). The light transmittance at the recording wavelength was measured before and after the recording. Hereinafter, each measurement method will be described in detail with reference to FIG.

(Measurement of M / #)
FIG. 1 is a configuration diagram showing an outline of an apparatus used for hologram recording.
In FIG. 1, S indicates a hologram recording medium, M1 and M2 both indicate mirrors, PBS indicates a polarization beam splitter, and L1 indicates a semiconductor laser light source for recording light that emits light having a wavelength of 405 nm (a single mode manufactured by TOPPICA Photonics). Laser), PD1
And PD2 indicate a photodetector (S2281 manufactured by Hamamatsu Photonics). Reference numeral 1 denotes a post-exposure LED unit.

  The light having a wavelength of 405 nm generated from L1 was divided by PBS, and crossed on the recording surface so that the angle formed by the two beams was 37.3 °. 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.

The above case was set to 0 °, and the angle of moving the hologram recording medium with respect to the optical axis was changed from -30 ° to 30 ° in increments of 1 degree, and 61-multiplex recording was performed.
After 61 multiple recording, the LED unit 1 (wavelength 405 nm) was turned on for a certain period of time to perform post-exposure, and the polymerizable monomer remaining without being polymerized was completely polymerized.
Subsequently, only the light (wavelength 405 nm) from the mirror M1 in FIG. 1 is irradiated as the reference light, the reproduction light is detected by PD1 and PD2, and a photosensor amplifier (C9329 manufactured by Hamamatsu Photonics, not shown) is used. The diffraction efficiency from an angle of −30 ° to 30 ° was measured. The sum of the square roots of the obtained diffraction efficiencies over the entire multiple recording area was defined as M / #.

Using a plurality of hologram recording media prepared for each example and comparative example, the evaluation was performed a plurality of times by changing the increase and decrease of the irradiation energy at the initial stage of recording and the increase and decrease of the total irradiation energy. The irradiation energy was changed in the range of 10 to 3000 mJ / cm ² by changing the irradiation time with the power density of L1 being 15 mW / cm ² . Specifically, several percent for each recording
While maintaining the above diffraction efficiency, a condition for allowing the contained monomer to polymerize almost completely by 61 multiplex recording (M / # almost reaches equilibrium by 61 multiplex recording) was sought, and the maximum value was obtained as M / #. I was able to. The maximum value obtained was defined as M / # of the medium.

(Post-exposure transmittance)
The degree of change in transmittance of the recording layer due to post-exposure was measured. As with the post-exposure operation, an unrecorded hologram recording medium is irradiated with a spatially uniform light from the LED unit 1 while changing the ratio of the transmitted light power to the incident light power. As measured.

The power density of the incident light is constant and 20 mW / cm ^2, and the power of the light that has passed through the hologram recording medium while irradiating the hologram recording medium with the incident light is measured with a power meter (ADC optical power meter 8250A and ADC light). Measurement was performed with a sensor 82321B). At this time, the surface of the hologram recording medium was arranged so as to be perpendicular to the optical axis. Immediately after the start of incident light irradiation, the respective transmittances were calculated when the integrated energy was 10 J / cm ² and 50 J / cm ² .
Table 2 shows the results of evaluating the hologram recording media produced in Examples 7 to 12 and Comparative Examples 1 and 2 by the above method. For the measurement of M / #, a hologram recording medium having a recording layer thickness of 0.5 mm was used.
For the measurement of the post-exposure transmittance, a hologram recording medium having a recording layer thickness of 1.5 mm was used.

Since the same M / # is measured using any of the compounds of Examples and Comparative Examples, the initial recording performance is considered to be equivalent.
By irradiating up to 10 J / cm ² immediately after the start of post-exposure, the transmittance of each hologram recording medium is improved to about 80% and the effect of post-exposure is obtained. In Comparative Examples 1 and 2, A clear decrease in transmittance is observed as the exposure energy increases from 10 J / cm ² to 50 J / cm ² . This indicates that the transmissivity decreases due to the progress of post-exposure and reproduction by light, and the recording layer is colored, which means that the signal intensity of the reproduction light decreases. That is, the S / N ratio at the time of reproducing recorded data decreases, and the reliability as a recording medium deteriorates.

On the other hand, in Examples 7 to 12, the transmittance hardly changed even when the post-exposure energy was increased, indicating that the coloration of the recording layer as described above was suppressed, and due to a decrease in the signal intensity of the reproduction light. The deterioration of the S / N ratio is suppressed.
It is apparent that this phenomenon is caused by the structure of the skeleton portion that absorbs light of the photopolymerization initiator of the present invention, regardless of the radical species generated (Comparative Example 1: Methyl radical, Comparative Example 2: Phenyl radical). The photopolymerization initiator of the present invention changes the substituent R ⁵ of the formula (1) from a substituent in which a conjugated system such as a phenyl group of the comparative compound is continuous to an alkyl group that is not conjugated. It is presumed that the absorption spectrum derived from the decomposition product was shorter than the comparative compound.

S Hologram recording medium M1, M2 Mirror L1 Recording laser diode laser light source PD1, PD2 Photodetector PBS Polarizing beam splitter 1 LED unit

Claims (6)

A hologram recording medium composition comprising a compound having a polymerizable reactive group and a photopolymerization initiator, wherein the photopolymerization initiator is represented by the following formula (1): .

[R ¹ represents an alkyl group;
R ² represents any one of an alkyl group, an aryl group, and an aralkyl group,
R ³ represents a — (CH ₂ ) _n — group, n represents an integer of 1 to 6,
R ⁴ represents a hydrogen atom or an arbitrary substituent,
R ⁵ represents an arbitrary substituent having no multiple bond conjugated to the carbonyl group to be bonded. ] The composition for a hologram recording medium according to claim 1, wherein R ⁴ represents any one of an alkyl group, an alkoxycarbonyl group, an aromatic ring group, and a heterocyclic group. The composition for a hologram recording medium according to claim 1, wherein R ⁵ represents an alkyl group. The composition for a hologram recording medium according to any one of claims 1 to 3, further comprising a compound having an isocyanate group and / or a compound having an isocyanate-reactive functional group.   A hologram recording medium using the composition for a hologram recording medium according to any one of claims 1 to 4. A compound represented by the following formula (2).

[R ¹ represents an alkyl group;
R ² represents any one of an alkyl group, an aryl group, and an aralkyl group,
R ³ represents a — (CH ₂ ) _n — group, n represents an integer of 1 to 6,
R ⁴ represents an alkoxycarbonyl group,
R ⁵ represents a branched alkyl group. ]

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