JP4946972B2 - Hologram recording material and hologram recording medium - Google Patents

Description

  The present invention relates to a hologram recording material suitable for volume hologram recording, and a hologram recording medium having the hologram recording material. In particular, the present invention relates to a hologram recording material suitable for recording / reproduction using not only green laser light but also blue laser light, and a hologram recording medium having the hologram recording material.

  Research and development of holographic memory is underway as a recording technology that enables high-capacity and high-speed transfer. Properties required for the hologram recording material include high refractive index change, high sensitivity, low scattering, environmental resistance, that is, storage stability, durability, low dimensional change, and high multiplicity during recording.

  As a hologram recording material, an organic-inorganic hybrid material mainly composed of an inorganic matrix and a photopolymerizable monomer has attracted attention and has been studied. The inorganic matrix is excellent in environmental resistance and durability.

  For example, Japanese Patent No. 2953200 discloses an optical recording film containing a photopolymerizable monomer or oligomer and a photopolymerization initiator in an inorganic substance network film. Monofunctional (meth) acrylic acid esters, polyfunctional (meth) acrylic acid esters, and the like are disclosed as photopolymerizable monomers (paragraph [0017]).

  Japanese Patent Application Laid-Open No. 11-344917 discloses an optical recording medium containing a photoactive monomer in an organic-inorganic hybrid matrix. As the photoactive monomer, an acrylate monomer such as diethylene glycol monoethyl ether acrylate is disclosed (paragraph [0018]).

  Japanese Patent Laid-Open No. 2002-236439 discloses an organic-inorganic obtained by copolymerizing an organometallic compound containing an ethylenically unsaturated double bond as a main chain component and an organic monomer having an ethylenically unsaturated double bond. A hologram recording material including a matrix composed of a hybrid polymer and / or a hydrolyzed polycondensate thereof, a photopolymerizable compound, and a photopolymerization initiator is disclosed. Examples of the photopolymerizable compound include a photoradical polymerizable compound and a photocationic polymerizable compound (paragraph [0041]), and a (meth) acrylic acid ester monomer is disclosed as the photoradical polymerizable compound (paragraph [ 0042] to [0043]).

  Japanese Patent Application Laid-Open No. 2005-77740 discloses a hologram recording material containing metal oxide particles, a polymerizable monomer, and a photopolymerization initiator. As the polymerizable monomer, a (meth) acrylic acid ester monomer is disclosed (paragraph [0020]).

  Japanese Unexamined Patent Application Publication No. 2005-99612 discloses a hologram recording material containing a compound having one or more polymerizable functional groups, a photopolymerization initiator, and colloidal silica particles. As the polymerizable functional group, an acrylate monomer is disclosed (paragraphs [0019] to [0022]), and acrylamides (ethylenebisacrylamide) are disclosed as another example (paragraph [0023]).

  Japanese Patent Application Laid-Open No. 2005-321684 has at least two kinds of metals (Si, Ti), oxygen, and aromatic groups, and two aromatic groups are directly bonded to one metal (Si). A hologram recording material containing an organometallic compound having an organometallic unit and a photopolymerizable compound is disclosed. Examples of the photopolymerizable compound include a radical polymerizable compound and a cationic polymerizable compound (paragraph [0039]), and a (meth) acrylic acid ester is disclosed as the radical polymerizable compound (paragraph [0041]).

  Japanese Patent Application Laid-Open No. 2008-58834 discloses a hologram recording medium including at least a hologram recording material layer, and the hologram recording material layer includes an organometallic compound having a Ti—O bond and a Si—O bond, a photopolymerizable compound, and Is disclosed, and the recording medium has a light transmittance of 50% or more at a wavelength of 405 nm, or a hologram recording medium having a light reflectance of 25% or more at a wavelength of 405 nm. As the photopolymerizable compound, (meth) acrylic acid ester is disclosed (paragraph [0060]).

  Japanese Patent Laid-Open No. 2008-58838 includes Si and at least one selected from the group consisting of Ta and Zr as a metal, and a complex-forming ligand is coordinated to Ta and / or Zr. A hologram recording material containing a metal oxide and a photopolymerizable compound is disclosed. The complex-forming ligand is selected from the group consisting of β-dicarbonyl compounds, polyhydroxylated ligands, and α- or β-hydroxy acids. Examples of the photopolymerizable compound include a radical polymerizable compound and a cationic polymerizable compound (paragraph [0046]), and a (meth) acrylic acid ester is disclosed as the radical polymerizable compound (paragraph [0047]).

Japanese Patent No. 2953200 JP-A-11-344917 JP 2002-236439 A JP 2005-77740 A Japanese Patent Laid-Open No. 2005-99612 JP-A-2005-321684 JP 2008-58834 A JP 2008-58838 A

  In the said patent document, (meth) acrylic acid ester is disclosed as a photopolymerizable monomer. However, (meth) acrylic acid esters are easily hydrolyzed under acidic or basic conditions. In addition, (meth) acrylic acid esters are also susceptible to transesterification by interaction with a metal alkoxide compound or a multimer thereof, which is a metal oxide matrix forming material. Therefore, when (meth) acrylic acid ester is applied as a photopolymerizable monomer to the metal oxide matrix, (meth) acrylic acid ester is gradually decomposed, resulting in deterioration of hologram recording characteristics.

  The shorter the wavelength of the recording / reproducing laser, the higher the mechanical strength, the high flexibility, the high homogeneity, and the environmental resistance (storage stability) of the hologram recording layer are required. Insufficient mechanical strength of the hologram recording layer leads to an increase in shrinkage during recording and a decrease in storage reliability. In particular, in order to obtain a sufficient contrast of refractive index modulation with a recording / reproducing laser in a short wavelength region, it is preferable to increase the microscopic mechanical strength to some extent and suppress monomer movement and dark reaction after recording exposure. If the hologram recording layer is not sufficiently flexible, the movement of the photopolymerizable monomer during recording will be hindered, leading to a decrease in sensitivity. If the homogeneity is insufficient, scattering will occur during recording / reproduction. / The reliability of the playback itself is reduced. The influence of scattering due to the inhomogeneity of the recording layer is more apparent in the recording / reproducing laser in the short wavelength region.

  The object of the present invention is to provide high refractive index change, flexibility, high sensitivity, low scattering, environmental resistance, that is, storage stability, durability, low dimensions, in holographic memory recording using not only a green laser but also a blue laser. An object of the present invention is to provide a hologram recording material suitable for volume hologram recording, in which change (low shrinkage) and high multiplicity are achieved. Another object of the present invention is to provide a hologram recording medium having a hologram recording layer made of the hologram recording material.

The present invention includes the following inventions.
(1) A hologram recording material comprising an organic group-containing metal compound and a photopolymerizable compound,
The organic group-containing metal compound contains an oxygen atom and a metal other than Si and Si as a metal, and has a metal-oxygen-metal bond,
A hologram recording material in which at least a part of oxygen atoms not forming the metal-oxygen-metal bond is capped with (meth) acrylic acid.
Here, the photopolymerizable compound is a photopolymerizable monomer other than (meth) acrylic acid.

  In this specification, (meth) acrylic acid is a general term for methacrylic acid and acrylic acid.

  (2) The hologram recording material according to (1), wherein the metal other than Si is selected from the group consisting of Ti, Zr, Ta, Sn, Al, and Zn.

  (3) The hologram recording material according to the above (1) or (2), wherein the organic group-containing metal compound contains a polydentate ligand coordinated to the metal.

  (4) The hologram recording material according to (3), wherein the polydentate ligand is selected from the group consisting of a β-dicarbonyl compound, a polyhydroxylated ligand, and an α- or β-hydroxy acid. .

  (5) The hologram recording material according to any one of (1) to (4), wherein the photopolymerizable compound is selected from (meth) acrylic acid esters.

  (6) The hologram recording material according to any one of (1) to (5), further comprising a photopolymerizable initiator.

  (7) The hologram according to any one of (1) to (6), wherein the organic group-containing metal compound has an organometallic unit in which two aromatic groups are directly bonded to Si. recoding media.

  (8) A hologram recording medium having a hologram recording layer made of the hologram recording material according to any one of (1) to (7).

  (9) The hologram recording medium according to (8), which is recorded / reproduced by a laser beam having a wavelength of 350 to 450 nm.

  (10) The hologram recording medium according to (8) or (9), wherein the hologram recording layer has a thickness of at least 0.1 mm (100 μm).

(11) When the hologram recording medium after production is stored in an environment of 80 ° C. for 7 days,
Based on the amount of photopolymerizable compound present in the hologram recording layer before storage,
The hologram recording medium according to any one of the above (8) to (10), wherein the amount of the photopolymerizable compound present in the hologram recording layer after storage is 50% or more.

(12) A method for producing the hologram recording medium according to any one of (1) to (6) above,
Mixing an alkoxide compound of Si and / or a hydrolyzate thereof with an alkoxide compound of another metal other than Si;
Hydrolyzing and condensing the mixed alkoxide compound to obtain a precursor of an organic group-containing metal compound;
After the hydrolysis, adding (meth) acrylic acid to the reaction mixture;
After adding (meth) acrylic acid, mixing the photopolymerizable compound with the reaction mixture;
A step of proceeding a polycondensation reaction of a precursor of an organic group-containing metal compound mixed with a photopolymerizable compound to obtain a hologram recording material;
A method for producing a hologram recording material comprising:
Here, the photopolymerizable compound is a photopolymerizable monomer other than (meth) acrylic acid.

  (13) The method for producing a hologram recording material according to (12), wherein the metal other than Si is selected from the group consisting of Ti, Zr, Ta, Sn, Al, and Zn.

(14) Before the step of mixing the alkoxide compound of Si and / or a hydrolyzate thereof with an alkoxide compound of a metal other than Si,
Mixing an alkoxide compound of a metal other than Si and a polydentate ligand, and modifying the alkoxide compound of a metal other than Si with a polydentate ligand, (12) or (13) The method for producing a hologram recording material according to (13).

  (15) The hologram recording material according to (14), wherein the polydentate ligand is selected from the group consisting of a β-dicarbonyl compound, a polyhydroxylated ligand, and an α- or β-hydroxy acid. Manufacturing method.

  (16) The method for producing a hologram recording material according to any one of (12) to (15), wherein the photopolymerizable compound is selected from (meth) acrylic acid esters.

  For metal compounds (metal oxides) formed by hydrolysis and condensation reactions of metal alkoxide compounds (so-called sol-gel reactions), reaction active points derived from the raw metal alkoxide compounds (for example, metal alkoxide compounds or condensation thereof) It is considered that there are not a few (alkoxyl groups or hydrolyzed OH groups) in the body. Such reaction active sites cause decomposition of the photopolymerizable compound, particularly (meth) acrylic acid ester.

  According to the present invention, the hologram recording material includes a photopolymerizable compound and an organic group-containing metal compound that functions as a dispersion medium for the matrix or the photopolymerizable compound, and the organic group-containing metal compound includes oxygen atoms, The metal contains Si and another metal other than Si, has a metal-oxygen-metal bond, and at least a part of the oxygen atoms not forming the metal-oxygen-metal bond is (meth) acrylic Capped with acid.

  The oxygen atom that does not form the metal-oxygen-metal bond constitutes an alkoxyl group (metal-oxygen-alkyl group) derived from the starting metal alkoxide compound or a hydrolyzed OH group (metal-OH group). Oxygen atom. Since such oxygen atoms have reaction activity, the aging stability of the hologram recording material is adversely affected. In the present invention, by using (meth) acrylic acid, a coordination of (meth) acrylic acid or a bond with (meth) acrylic acid is formed on the alkoxyl group or OH group having reaction activity, and the reaction Reduce and suppress activity. Such an operation or form is called “capping”. As a result, according to the hologram recording medium of the present invention, the photopolymerizable compound can be stably present.

  Furthermore, according to the present invention, the organic group-containing metal compound that functions as a dispersion medium for the matrix or the photopolymerizable compound is coordinated with an oxygen atom, a metal other than Si and Si, preferably the metal. The hologram recording material has a very uniform form. Therefore, a holographic recording material suitable for recording / reproducing with blue laser light as well as green laser light is provided.

  The hologram recording material of the present invention comprises a composition containing an organic group-containing metal compound and a photopolymerizable compound (monomer) and further containing (meth) acrylic acid. The organic group-containing metal compound contains oxygen atoms and metals other than Si and Si as metals. The metal other than Si may be selected from the group consisting of Ti, Zr, Ta, Sn, Al, and Zn. By including two or more kinds of metals as constituent elements, it is easy to control characteristics such as refractive index, which is preferable in recording material design. The hologram recording material is formed into a film to form a hologram recording layer. In this specification, the hologram recording layer is sometimes referred to as a hologram recording material layer.

  The organic group-containing metal compound is obtained by hydrolysis and polymerization reaction (so-called sol-gel reaction) of an alkoxide compound of Si and an alkoxide compound of a metal other than Si, and has a very uniform form. It is in the form of gel or sol. The organic group-containing metal compound functions as a matrix or a dispersion medium for the photopolymerizable compound in the hologram recording layer. That is, the liquid phase photopolymerizable compound is uniformly and well dispersed in the organic group-containing metal compound in a gel or sol form.

  When the hologram recording layer is irradiated with coherent light, the photopolymerizable organic compound (monomer) undergoes a polymerization reaction in the exposed area to become a polymer, and the photopolymerizable organic compound diffuses from the unexposed area to the exposed area. In addition, the exposed portion is further polymerized. As a result, a polymer-rich region and a polymer-poor region generated from the photopolymerizable organic compound are formed according to the light intensity distribution. At this time, the organic group-containing metal compound moves from the polymer-rich region to the polymer-poor region, the polymer-rich region becomes the metal compound-poor region, and the polymer-poor region is the metal compound-poor region. There are many areas. In this way, a region having a large amount of the polymer and a region having a large amount of the metal compound are formed by exposure, and when there is a refractive index difference between the polymer and the metal compound, the refractive index changes according to the light intensity distribution. Is recorded.

  In order to obtain better recording characteristics in the hologram recording layer, it is necessary that the difference between the refractive index of the polymer generated from the photopolymerizable compound and the refractive index of the metal compound is large. As for the refractive indexes of both the polymer and the metal compound, either one may be designed to be higher and the other may be designed to be lower.

  If a large amount of Si is used, a design in which the refractive index of the metal compound is made low can be considered. However, in the present invention, the metal compound contains a metal other than Si selected from Ti, Zr, Ta, Sn, Al and Zn as an essential constituent element, so that the metal compound has a high refractive index. Obtainable. Therefore, the hologram recording material may be designed with the metal compound as a high refractive index and the polymer as a low refractive index.

The number of Si in the metal compound and the number of metals other than Si may be appropriately determined in consideration of a desired refractive index. For example, the number of Si (s) and the number of other metals (Ti, Zr, Ta, Sn, Al, Zn) other than Si (m) are:
0.3s ≦ m ≦ 3s
It is preferable that the relationship is satisfied.

  In the present invention, it is preferable that an organic ligand is coordinated to at least a part of other metals (Ti, Zr, Ta, Sn, Al, Zn) other than the Si constituting the metal compound. As the organic ligand, a so-called chelate ligand can be used as the polydentate ligand. For example, a β-dicarbonyl compound, a polyhydroxylated ligand, and an α- or β-hydroxy acid, ethanol Examples include amines. Examples of the β-dicarbonyl compound include β-diketones such as acetylacetone (AcAc) and benzoylacetone, and β-ketoesters such as ethyl acetoacetate (EtAcAc). Polyhydroxylated ligands include glycols (especially those of the 1,3-diol type, such as 1,3-propanediol, 2-ethyl-1,3-hexanediol), α- or β-hydroxy acids Examples thereof include lactic acid, glyceric acid, tartaric acid, citric acid, tropic acid, and benzylic acid. Examples of other ligands include oxalic acid.

  Aromatic carboxylic acids are also preferred as the ligand. An aromatic carboxylic acid is a compound in which one or more carboxylic acids (—COOH) are bonded directly to the aromatic ring (Ar). Aromatic carboxylic acids include aromatic monocarboxylic acids such as benzoic acid, o-, m-, or p-toluic acid, o-, m-, or p-methoxybenzoic acid; aromatics such as phthalic acid and terephthalic acid Group dicarboxylic acids.

  When a mixture of an alkoxide compound of Si and an alkoxide compound of a metal other than Si (Ti, Zr, Ta, Sn, Al, Zn) is subjected to a sol-gel reaction, the alkoxide compound of Si is hydrolyzed and polymerized. The reaction rate is generally small, and the alkoxide compound of the metal other than Si has a high rate of hydrolysis and polymerization reaction, so that the oxides of other metals other than Si aggregate and a homogeneous sol-gel reaction No product is obtained.

  Therefore, a silanol compound, which is a hydrolyzate of Si alkoxide compound, is used as a starting material, or Si alkoxide compound is hydrolyzed and then mixed with an alkoxide compound of another metal other than Si. Good. Thereby, a homogeneous sol-gel reaction product is obtained.

  Alternatively, the hydrolysis and polymerization reaction can be suppressed by coordinating an organic ligand, preferably the above-mentioned chelate ligand, to an alkoxide compound of a metal other than Si to suppress the hydrolysis and polymerization reaction. A homogeneous sol-gel reaction product is obtained from the mixture with the compound.

  For example, in the case of a Ti alkoxide compound, 1,3-propanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 2-ethyl-1,3-hexanediol, 2-methyl- It is preferable to coordinate a glycol such as 2,4-pentanediol.

  The above-mentioned glycol (ie, 1,3-diol) is easy to be multidentately coordinated to the Ti atom of the Ti alkoxide compound raw material, satisfies the coordinated position of the Ti atom, and is still another coordination compound during the sol-gel reaction. Is considered to inhibit hydrolysis and polymerization reaction. When the glycol is coordinated to the Ti alkoxide compound, the Ti alkoxide compound such as tetrabutoxy titanium and tetraethoxy titanium and the glycol are mixed in a solvent such as ethanol and butanol at room temperature, for example, and stirred. Good. In this case, the same solvent as that used in the sol-gel reaction may be used as the solvent. In this way, an alkoxide compound of Ti coordinated with glycol is prepared.

  In the case of a Ti alkoxide compound, it is also preferable to coordinate polyalkylene glycol as glycol. Examples of the polyalkylene glycol include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and tetrapropylene glycol.

  Like the 1,3-diol, the polyalkylene glycol described above easily coordinates to the Ti atom of the Ti alkoxide compound raw material, satisfies the coordination position of the Ti atom, and has another coordination property during the sol-gel reaction. Inhibits the compound from coordinating to the Ti atom. Coordination of the polyalkylene glycol to the Ti alkoxide compound is preferably performed in the same manner as in the case of 1,3-diol coordination. Among the above-described polyalkylene glycols, dipropylene glycol is preferable from the viewpoint of coordination ability and availability.

For example, a polydentate ligand is coordinated to an alkoxide compound Zr (OR) ₄ (wherein R is an alkyl group) of Zr, and the alkoxide compound such as Zr (OR) ₂ (AcAc) ₂ is changed. As a result, the number of alkoxyl groups that can contribute to hydrolysis and polymerization reaction is reduced, and further, the reactivity of the alkoxyl group is suppressed by the steric factor of the chelate ligand such as acetylacetone (AcAc), It is considered that hydrolysis and polymerization reaction are suppressed by the above. The same applies to the alkoxide compound Ta (OR) ₅ of Ta.

Further, for example, an aromatic carboxylic acid is coordinated to an alkoxide compound Zr (OR) ₄ (wherein R is an alkyl group) of Zr, and a cluster containing several Zr, Zr (OR) ₃ (HOOCAr), Zr It is thought that it changes to Zr alkoxide compounds such as (OR) ₂ (HOOCAr) ₂ and Zr (OR) (HOOCAr) ₃ . Or it is thought that aromatic carboxylic acid may coordinate over Zr of two molecules of Zr alkoxide. As a result, the number of alkoxyl groups that can contribute to the hydrolysis and polymerization reaction is reduced, and further, the reactivity of the alkoxyl group is suppressed by the steric factor of the aromatic carboxylic acid compound, thereby causing hydrolysis and polymerization reaction. Is considered to be suppressed.

  Thus, the organic group-containing metal compound in the present invention is in a very uniform form of gel or sol.

  The amount of the organic ligand to be used is not particularly limited, but based on the amount of the alkoxide compound of the metal (M) other than Si in consideration of the above-described sol-gel reaction suppressing action and reaction activity suppressing action. It may be determined as appropriate. For example, the molar ratio (organic ligand / M) of the organic ligand to the metal atom (M) of the alkoxide compound of the metal (M) other than Si is 0.8 / 1 or more and 3/1 or less, It is preferable to set it to 1/1 or more and 2.5 / 1 or less, more preferably 1.5 / 1 or more and 2/1 or less.

  As described above, a sol of the organic group-containing metal compound (composite oxide) containing Si and another metal (M) other than Si can be obtained. In the obtained composite oxide in the form of fine particles, in addition to the bond (Si—OM) between the Si atom and another metal (M) atom other than Si (Si—OM), the oxygen atom between the Si atoms It is considered that a bond via Si (O—Si) and a bond via an oxygen atom between other metal (M) atoms other than Si (M—O—M) are included. In addition, the obtained composite oxide sol is mainly composed of a bond (Si—O—Si) through an oxygen atom between Si atoms, and does not contain other metal (M) atoms other than Si, It is considered that fine particles not mainly containing Si atoms but mainly containing a bond (M-OM) via oxygen atoms between other metal (M) atoms other than Si are included. That is, in this case, the composite oxide sol includes fine particles made of a composite oxide of Si and another metal, fine particles made of an Si oxide, and fine particles made of an oxide of another metal other than Si. It becomes the form of mixed sol.

  In the present invention, when the organic group-containing metal compound has an organometallic unit (Ar-M-Ar) in which two aromatic groups are directly bonded to Si, such an organic group-containing metal compound The matrix made of is preferable in that it has flexibility and compatibility with the photopolymerizable compound. More preferably, the organometallic unit (Ar—Si—Ar) is a unit (Ph—Si—Ph) in which two phenyl groups (Ph) are directly bonded to one Si. The diphenylalkoxide compound of Si is easily available as a raw material, and the reactivity of hydrolysis and polymerization is also good. Moreover, the phenyl group may have a substituent.

  The preferred organic group-containing metal compound has an organometallic unit in which two aromatic groups are directly bonded to one metal, but in addition to such an organometallic unit, one aromatic group per one metal. May have an organometallic unit directly bonded, or may have an organometallic unit in which three aromatic groups are directly bonded to one metal.

  In the present invention, an organic group other than an aromatic group, such as an alkyl group, may be introduced into Si of the organic group-containing metal compound. For example, methylphenyldimethoxysilane or the like can be used as long as the effects of the present invention are not impaired. In addition, when a monoalkoxysilane such as trimethylmethoxysilane is present, the polymerization reaction is stopped, so that the monoalkoxysilane can be used for adjusting the molecular weight.

  In addition, the metal compound may contain other trace elements other than those described above.

  Generally, a metal compound (metal oxide) formed by hydrolysis and condensation reaction (so-called sol-gel reaction) of a metal alkoxide compound includes a reactive site derived from a raw metal alkoxide compound (for example, metal alkoxide). The compound or its condensate alkoxyl group or hydrolyzed OH group) is considered to be present in a small amount. Such reaction active sites cause decomposition of the photopolymerizable compound described below, particularly (meth) acrylic acid ester.

  In the present invention, in the organic group-containing metal compound, at least a part or all of oxygen atoms not forming the metal-oxygen-metal bond are capped with (meth) acrylic acid. The oxygen atom that does not form the metal-oxygen-metal bond constitutes an alkoxyl group (metal-oxygen-alkyl group) derived from the starting metal alkoxide compound or a hydrolyzed OH group (metal-OH group). Oxygen atom. Since such oxygen atoms have reaction activity, the aging stability of the hologram recording material is adversely affected. In the present invention, by using (meth) acrylic acid, a coordination of (meth) acrylic acid or a bond with (meth) acrylic acid is formed on the alkoxyl group or OH group having reaction activity, and the reaction Reduce and suppress activity. Such an operation or form is called “capping”. As a result, according to the hologram recording medium of the present invention, the photopolymerizable compound can exist stably over time.

  In the present invention, the amount of (meth) acrylic acid is not particularly limited, but may be appropriately determined based on the amount of metal other than Si (M). The amount of (meth) acrylic acid is preferably 0.1 to 1.0 mol, and preferably 0.12 to 0.6 mol, relative to the metal amount (mol) of the other metal (M) other than Si. Is more preferable.

The reason for determining based on the amount of metal other than Si (M) other than Si is as follows.
Si is less reactive than other metals (M) other than Si, and after forming Si-OM bonds with other metals (M), Si-alkyl groups or Si-OH groups of Si remain. Even so, (meth) acrylic acid is unlikely to coordinate with the oxygen atoms constituting them. In other words, even if the Si-alkyl group or Si-OH group of Si remains in the organic group-containing metal compound, the reaction activity of oxygen atoms constituting these is low, and the photopolymerizable compound, particularly The ability to decompose (meth) acrylic acid esters is considered low.

  The metal (M) other than Si will be described by taking as an example the case of Ti tetraalkoxide having four alkoxyl groups. If one alkoxide is consumed for bonding with Si (Ti-O-Si) and another alkoxide is consumed for bonding with Ti (Ti-O-Ti) by the sol-gel reaction, it remains. There are two active sites (Ti-O-alkyl group or Ti-OH group). However, when Ti does not have a ligand, it is considered that it is difficult to suppress the bonding between Ti. Therefore, the Ti domain easily grows (is likely to become large), and the active sites appearing on the surface of the formed sol particles are further increased. It is thought to be reduced. For this reason, even if Ti does not have a ligand, it is considered sufficient to use about 0.5 mol of (meth) acrylic acid with respect to Ti. When Ti has a ligand, the amount of (meth) acrylic acid may be further reduced. On the other hand, if (meth) acrylic acid is present excessively, the reactivity of (meth) acrylic acid itself is high, which may cause the entire hologram recording material system to become unstable, and causes coloring.

  The same applies to metals other than Ti (Zr, Ta, Sn, Al, Zn, etc.). For the above reasons, the amount of (meth) acrylic acid is appropriately determined based on the amount of metal other than Si (M) and the amount of alkoxyl group.

  In the present invention, the photopolymerizable compound is a photopolymerizable monomer. As the photopolymerizable compound, a compound selected from a radical polymerizable compound and a cationic polymerizable compound can be used.

  The radically polymerizable compound is not particularly limited as long as it has one or more radically polymerizable unsaturated double bonds in the molecule. For example, a monofunctional or polyfunctional compound having a (meth) acryloyl group or a vinyl group can be used. Functional compounds can be used. The (meth) acryloyl group is a generic term for a methacryloyl group and an acryloyl group.

Among such radically polymerizable compounds, compounds having a (meth) acryloyl group include phenoxyethyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and benzyl (meth). Acrylate, cyclohexyl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methyl (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, stearyl (meth) acrylate, etc. Monofunctional (meth) acrylate;
Trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate Polyfunctional (meth) acrylates such as polyethylene glycol di (meth) acrylate, bis (2-hydroxyethyl) isocyanurate di (meth) acrylate, 2,2-bis [4- (acryloxy-diethoxy) phenyl] propane;
However, it is not necessarily limited to these.

  Examples of the compound having a vinyl group include monofunctional vinyl compounds such as monovinylbenzene and ethylene glycol monovinyl ether; polyfunctional vinyl compounds such as divinylbenzene, ethylene glycol divinyl ether, diethylene glycol divinyl ether, and triethylene glycol divinyl ether. However, it is not necessarily limited to these.

  Only 1 type of radically polymerizable compound may be used, and 2 or more types may be used together. In the present invention, when the organic group-containing metal compound has a high refractive index and the organic polymer has a low refractive index, a low refractive index having no aromatic group among the above radical polymerizable compounds (for example, And a refractive index of 1.5 or less) are preferred. In order to further improve the compatibility with the metal compound, more hydrophilic glycol derivatives such as polyethylene glycol (meth) acrylate and polyethylene glycol di (meth) acrylate are preferred.

  Considering the action of (meth) acrylic acid in the hologram recording material as described above, the advantage of the present invention is great when (meth) acrylic acid esters are used as the photopolymerizable compound.

  In the present invention, the photopolymerizable compound is used, for example, about 5 to 1000% by weight, preferably 10 to 300% by weight, based on the weight of the whole metal compound. If it is less than 5% by weight, it is difficult to obtain a large refractive index change during recording, and if it exceeds 1000% by weight, it is difficult to obtain a large refractive index change during recording.

  In the present invention, the hologram recording material preferably further contains a photopolymerization initiator corresponding to the wavelength of the recording light. When a photopolymerization initiator is contained, the polymerization of the photopolymerizable compound is promoted by exposure during recording, and higher sensitivity can be obtained.

  When a radical polymerizable compound is used as the photopolymerizable compound, a photo radical initiator is used. On the other hand, when a cation polymerizable compound is used as the photopolymerizable compound, a photo cation initiator is used.

  Examples of the photo radical initiator include Darocur 1173, Irgacure 784, Irgacure 651, Irgacure 184, and Irgacure 907 (all manufactured by Ciba Specialty Chemicals). The content of the photo radical initiator is, for example, about 0.1 to 10% by weight, preferably about 0.5 to 5% by weight, based on the radical polymerizable compound.

  It is preferable that a dye functioning as a photosensitizer corresponding to the recording light wavelength is contained in addition to the photopolymerization initiator. Examples of the photosensitizer include thioxanthones such as thioxanthen-9-one and 2,4-diethyl-9H-thioxanthen-9-one, xanthenes, cyanines, merocyanines, thiazines, acridines, Anthraquinones, squaryliums, etc. are mentioned. The amount of the photosensitizer used is preferably about 3 to 50% by weight of the photo radical initiator, for example, about 10% by weight.

Next, production of the hologram recording material will be described.
The hologram recording material of the present invention is not particularly limited,
A step of mixing an alkoxide compound of Si and an alkoxide compound of a metal other than Si;
Hydrolyzing and condensing the mixed alkoxide compound to obtain a precursor of an organic group-containing metal compound;
After the hydrolysis, adding (meth) acrylic acid to the reaction mixture;
After adding (meth) acrylic acid, mixing the photopolymerizable compound with the reaction mixture;
A step of proceeding a polycondensation reaction of a precursor of an organic group-containing metal compound mixed with a photopolymerizable compound to obtain a hologram recording material;
It is preferable to manufacture by the manufacturing method of a hologram recording material provided with these.

  When a multidentate ligand is coordinated to a metal other than Si, before the above-mentioned step of mixing an alkoxide compound of Si and an alkoxide compound of a metal other than Si, other than Si The step of mixing the metal alkoxide compound and the polydentate ligand and modifying the metal alkoxide compound other than Si with a polydentate ligand may be performed.

  That is, first, an alkoxide compound of a metal other than Si (Ti, Zr, Ta, Sn, Al, Zn) as a starting material and a polydentate ligand are mixed, and an alkoxide of a metal other than Si is mixed. The compound is modified with an organic ligand. The amount of the ligand may be appropriately determined in consideration of the reaction suppressing action described above. As the solvent at this time, the same solvent as that used in the sol-gel reaction may be used.

  Next, an alkoxide compound of a metal other than the Si modified with a ligand and suppressed in reactivity is mixed with an alkoxide compound of Si. As the Si alkoxide compound, an Si diaryl alkoxide compound is preferably used, and an Si diphenyl alkoxide compound is more preferably used.

  Next, the mixed alkoxide compound is hydrolyzed or condensed to obtain a precursor of the organic group-containing metal compound. This hydrolysis and polycondensation reaction can be carried out under the same operation and conditions as in the known sol-gel method. For example, a predetermined proportion of a metal alkoxide compound (a diphenyl alkoxide compound of Si and a modified alkoxide compound of a metal other than Si) is dissolved in an appropriate good solvent to form a uniform solution, and an appropriate acid catalyst for the solution. The reaction can be carried out by adding dropwise and stirring the solution in the presence of water.

  Examples of such a solvent include water; alcohols such as methanol, ethanol, propanol, isopropanol, and butanol; ethers such as diethyl ether, dioxane, dimethoxyethane, and tetrahydrofuran; N-methylpyrrolidone, acetonitrile, N, N— Examples include dimethylformamide, N, N-dimethylacetamide, dimethyl sulfoxide, acetone, and benzene. What is necessary is just to select suitably from these. Or it can also be set as these mixed solvents. Although the quantity of a solvent is not limited, It is good to set it as 10-1000 weight part with respect to 100 weight part of the whole metal alkoxide compound.

  Examples of the acid catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid; formic acid, acetic acid, trichloroacetic acid, trifluoroacetic acid, propionic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, and the like. Organic acids and the like.

  Although it depends on the reactivity of the metal alkoxide compound, the hydrolysis polymerization reaction can generally be performed at room temperature, and can be performed at a temperature of about 0 to 150 ° C., preferably at a temperature of about room temperature to 50 ° C. The reaction time may be appropriately determined in relation to the reaction temperature, but is about 0.1 to 240 hours. The reaction may be performed under an inert atmosphere such as nitrogen gas, or may be performed under reduced pressure of about 0.5 to 1 atm while removing alcohol generated by the polymerization reaction.

  After the hydrolysis, (meth) acrylic acid is added to the reaction system. In order to suppress the reaction activity of unreacted alkoxyl groups and / or OH groups, heating (about 70 to 80 ° C.) and stirring (about 0.5 to 1 hour) may be appropriately performed.

  After the addition of (meth) acrylic acid, a photopolymerizable organic compound is mixed into the reaction system. The presence of (meth) acrylic acid makes it difficult for the photopolymerizable organic compound to decompose. At this time, in order to mix uniformly, it is preferable to add and mix the photopolymerizable organic compound while the sol-gel reaction system containing the metal compound or its precursor is in a sol state. Moreover, it is good to mix a photoinitiator and a photosensitizer at this stage.

  A polycondensation reaction of the metal compound precursor mixed with the photopolymerizable compound is allowed to proceed to obtain a target hologram recording material comprising a composition of an organic group-containing metal compound. This composition contains the metal compounds of various molecular weights.

  A film is obtained by applying a hologram recording material solution in which a photopolymerizable organic compound and the organic group-containing metal compound in a sol state are uniformly mixed on a substrate, followed by solvent drying and further a sol-gel reaction in some cases. A holographic recording material layer is obtained. In this manner, a hologram recording material layer in which the photopolymerizable organic compound is uniformly contained in the organic group-containing metal compound is produced.

  The hologram recording medium of the present invention comprises at least the hologram recording material layer. Usually, the hologram recording medium includes a support base (that is, a substrate) and a hologram recording material layer. However, the hologram recording medium may include only a hologram recording material layer without the support base. For example, by forming a hologram recording material layer on a substrate by coating and then peeling the hologram recording material layer from the substrate, a medium composed only of the hologram recording material layer can be obtained. In this case, the hologram recording material layer is a thick film of the order of mm, for example.

  The hologram recording medium of the present invention is based on the amount (initial) of the photopolymerizable compound present in the hologram recording layer before storage when the produced hologram recording medium is stored at 80 ° C. in a dry environment for 7 days. The residual amount of the photopolymerizable compound present in the hologram recording layer after storage is, for example, 50% or more, preferably 70% or more, more preferably 85%. Under the above accelerated test conditions, the recording medium in which the residual amount of the photopolymerizable compound present in the hologram recording layer after storage is 50% or more has no problem in storage stability under a normal environment and is practical. Has recording characteristics.

The remaining amount (%) of the photopolymerizable compound in the hologram recording layer after storage can be determined, for example, as follows.
A part of the hologram recording layer of the hologram recording medium after preparation is scraped off, and infrared spectroscopic measurement is performed on the scraped sample to obtain characteristic absorption (for example, Si-phenyl group of the organic group-containing metal compound matrix). the ratio of the intensities Aph the characteristic absorption 1591~1592cm ^-1) phenyl group, a strength AC = O of characteristic absorption of the photopolymerizable compound (here the acrylate C = O bond characteristic absorption 1726~1727cm ^-1) ( AC = O / Aph).
The hologram recording medium after preparation is stored at 80 ° C. in a dry environment for 7 days. A part of the hologram recording layer after storage is scraped off, and infrared spectroscopic measurement is performed on the scraped sample to obtain the organic group-containing metal compound. and strength Bph characteristics as a reference matrix absorption (Si- characteristic absorption of the phenyl group of the phenyl group 1591~1592cm ^-1), characteristic absorption of the photopolymerizable compound (acrylate C = O bond characteristic absorption 1726～1727Cm ^{- 1} ) The ratio (BC = O / Bph) with the intensity BC = O is obtained.

Before storage (initial) and after storage, the amount of the phenyl group of the Si-phenyl group serving as a reference for the organic group-containing metal compound matrix is unchanged.
Residual amount of photopolymerizable compound after storage (%)
= [(BC = O / Bph) / (AC = O / Aph)] × 100.

  You may pay attention to the characteristic absorption used as the appropriate reference | standard of the said organic group containing metal compound matrix besides the phenyl group of Si-phenyl group. Moreover, you may pay attention to the suitable characteristic absorption of the said photopolymerizable compound besides the C = O coupling | bonding of an acrylate. The residual amount (%) of the photopolymerizable compound after storage can be determined by the same method as described above. In addition, a quantitative method other than infrared spectroscopic measurement may be used.

  The hologram recording medium of the present invention is suitable not only for green laser light but also for recording / reproducing with blue laser light having a wavelength of 350 to 450 nm. When reproducing with transmitted light, it is preferable to have a light transmittance of 50% or more at a wavelength of 405 nm, and when reproducing with reflected light, it is preferable to have a light reflectance of 25% or more at a wavelength of 405 nm.

  The hologram recording medium is a medium configured to reproduce with transmitted light (hereinafter referred to as a transmitted light reproduction type) or a medium configured to reproduce with reflected light (hereinafter referred to as a reflected light reproduction type) depending on the optical system apparatus used. Either.

  By using the hologram recording material layer, a hologram recording medium having a recording layer thickness of 100 μm or more suitable for data storage can be obtained. The hologram recording medium can be produced by forming a film-like hologram recording material on a substrate or sandwiching a film-like hologram recording material between substrates.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.

[Example 1]
(Synthesis of matrix material)
To 5.0 g of diphenyldimethoxysilane (Ph ₂ Si (OMe) ₂ , manufactured by Shin-Etsu Chemical Co., Ltd.), a solution consisting of 0.37 mL of water, 0.15 mL of 2N hydrochloric acid aqueous solution, and 5.0 mL of the solvent 1-methoxy-2-propanol The mixture was added dropwise at room temperature while stirring, and stirring was continued for 1 hour to carry out a hydrolysis reaction. Thereafter, 5.82 g of tetraisopropoxytitanium (Ti (O—iPr) ₄ , manufactured by Azmax) was added to this reaction solution at room temperature, and then stirred at 80 ° C. for 1 hour to obtain a mixed solution. Ti / Si = 1/1 (molar ratio).

  To the obtained mixed solution, 0.75 mL of water and 1.5 mL of 1-methoxy-2-propanol were added at room temperature with stirring, and the stirring was continued for 1 hour, followed by further hydrolysis and condensation reaction.

  To the obtained solution, 0.88 g of methacrylic acid (MA) was added at room temperature with stirring, and then stirred at 80 ° C. for 1 hour. Ti / MA = 1 / 0.5 (molar ratio). In this way, a sol solution was obtained.

(Photopolymerizable compound)
100 parts by weight of polyethylene glycol monoacrylate (manufactured by Kyoeisha Chemical Co., 130A) as a photopolymerizable compound, 3 parts by weight of Irgacure IRG-907 (Ciba Specialty Chemicals) as a photopolymerization initiator, and 2,4 as a photosensitizer -0.3 part by weight of diethyl-9H-thioxanthen-9-one was added to obtain a mixture containing a photopolymerizable compound.

(Hologram recording material)
The sol solution and the photopolymerizable compound mixture are mixed at room temperature and shielded from light so that the ratio of the matrix material (as a non-volatile component) is 85 parts by weight and the ratio of the photopolymerizable compound is 15 parts by weight. Then, the sol-gel reaction was sufficiently advanced for 1 hour to obtain a hologram recording material solution.

(Hologram recording medium)
The obtained hologram recording material solution was applied onto a glass substrate as described below and dried to obtain a recording medium sample.

A description will be given with reference to FIG. 1 showing a schematic cross section of a hologram recording medium.
A 1 mm thick glass substrate (22) provided with an antireflection film (22a) on one side was prepared. A spacer (24) having a predetermined thickness is placed on the surface of the glass substrate (22) where the antireflection film (22a) is not provided, the resulting hologram recording material solution is applied, dried at room temperature for 1 hour, and then It dried at 40 degreeC for 24 hours and volatilized the solvent. By this drying step, gelation (condensation reaction) of the organic group-containing metal compound proceeds, and the hologram recording material layer (21) having a dry film thickness of 300 μm in which the organic group-containing metal compound and the photopolymerizable compound are uniformly dispersed is obtained. Obtained.

  The hologram recording material layer (21) formed on the glass substrate (22) was covered with another 1 mm thick glass substrate (23) provided with an antireflection film (23a) on one side. At this time, the surface of the glass substrate (23) where the antireflection film (23a) was not provided was covered so as to be in contact with the surface of the hologram recording material layer (21). Thus, a hologram recording medium (11) having a structure in which the hologram recording material layer (21) was sandwiched between two glass substrates (22) and (23) was obtained.

Part of the hologram recording layer of the prepared hologram recording medium sample is scraped, and the scraped sample is subjected to infrared spectroscopic measurement (apparatus: Nicolet, Magna 760), which becomes the reference for the organic group-containing metal compound matrix and strength Aph characteristic absorption 1591～1592Cm ^-1 phenyl group Si- phenyl group, was determined the ratio of the intensity AC = O of C = O bond characteristic absorption 1726～1727Cm ^-1 polyethylene glycol monoacrylate. AC = O / Aph = 1.60 / 1.

Next, the prepared hologram recording medium sample was stored at 80 ° C. in a dry environment for 7 days. A portion of the hologram recording layer after storage was scraped off, and the sample thus scraped was subjected to infrared spectroscopic measurement in the same manner, and a characteristic absorption 1591 to 1592 cm ⁻¹ of the phenyl group of the Si-phenyl group, an intensity Bph of polyethylene glycol mono The ratio of the characteristic absorption of C = O bond of acrylate to the strength BC = O of 1726 to 1727 cm ^-1 was determined. BC = O / Bph = 1.00 / 1.

Residual amount of photopolymerizable compound after storage (%)
= [(BC = O / Bph) / (AC = O / Aph)] × 100 As a result, the residual amount of the photopolymerizable compound after storage was 62.5%.

Infrared spectroscopic measurement conditions are shown below.
Apparatus: Nicolet, Magna 760
Measuring method: One-time reflection ART method (diamond)
ST Japan Use DuraScope Resolution: 4cm ^-1
Integration count: 32

[Comparative Example 1]
(Synthesis of matrix material)
To 5.0 g of diphenyldimethoxysilane (Ph ₂ Si (OMe) ₂ , manufactured by Shin-Etsu Chemical Co., Ltd.), a solution consisting of 0.37 mL of water, 0.15 mL of 2N hydrochloric acid aqueous solution, and 5.0 mL of the solvent 1-methoxy-2-propanol The mixture was added dropwise at room temperature while stirring, and stirring was continued for 1 hour to carry out a hydrolysis reaction. Thereafter, 5.82 g of tetraisopropoxytitanium (Ti (O—iPr) ₄ , manufactured by Azmax) was added to this reaction solution at room temperature, and then stirred at 80 ° C. for 1 hour to obtain a mixed solution. Ti / Si = 1/1 (molar ratio).

  To the obtained mixed solution, 0.75 mL of water and 1.5 mL of 1-methoxy-2-propanol were added at room temperature with stirring, and the stirring was continued for 1 hour, followed by further hydrolysis and condensation reaction. In this way, a sol solution was obtained.

  Using the obtained sol solution, a hologram recording medium was obtained in the same manner as in Example 1.

In the same manner as in Example 1, the produced hologram recording medium sample was stored at 80 ° C. in a dry environment for 7 days. When infrared spectroscopy was performed in the same manner as in Example 1,
Initial AC = O / Aph = 1.86 / 1
After storage BC = O /Bph=0.57/1
Met. The residual amount of the photopolymerizable compound after storage was 30.6%.

[Example 2]
(Synthesis of matrix material)
Tetraisopropoxytitanium (Ti (O-iPr) ₄ , manufactured by Azmax) 5.82 g and 2-methylpentane-2,4-diol (manufactured by Tokyo Chemical Industry) 4.83 g were mixed at room temperature and stirred for 30 minutes. A titanium-containing liquid mixture was obtained. Ti / the diol = 1/2 (molar ratio).
On the other hand, from 5.0 g of diphenyldimethoxysilane (Ph ₂ Si (OMe) ₂ , manufactured by Shin-Etsu Chemical Co., Ltd.) to 0.37 mL of water, 0.15 mL of 2N aqueous hydrochloric acid, and 5.0 mL of solvent 1-methoxy-2-propanol The resulting solution was added dropwise at room temperature while stirring, and stirring was continued for 1 hour to conduct a hydrolysis reaction to obtain a silicon-containing reaction solution.
The obtained silicon-containing reaction liquid was added to the titanium-containing mixed liquid at room temperature while stirring, and then stirred at 80 ° C. for 1 hour to obtain a mixed solution. Ti / Si = 1/1 (molar ratio).

  To the obtained mixed solution, 0.75 mL of water and 1.5 mL of 1-methoxy-2-propanol were added at room temperature with stirring, and the stirring was continued for 1 hour, followed by further hydrolysis and condensation reaction.

  To the obtained solution, 0.44 g of methacrylic acid (MA) was added at room temperature with stirring, and then stirred at 80 ° C. for 1 hour. Ti / MA = 1 / 0.25 (molar ratio). In this way, a sol solution was obtained.

  Using the obtained sol solution, a hologram recording medium was obtained in the same manner as in Example 1.

In the same manner as in Example 1, the produced hologram recording medium sample was stored at 80 ° C. in a dry environment for 7 days. When infrared spectroscopy was performed in the same manner as in Example 1,
Initial AC = O / Aph = 1.57 / 1
After storage BC = O /Bph=1.15/1
Met. The remaining amount of the photopolymerizable compound after storage was 73.2%.

[Example 3]
(Synthesis of matrix material)
Tetraisopropoxytitanium (Ti (O-iPr) ₄ , manufactured by Azmax) 5.82 g and 2-methylpentane-2,4-diol (manufactured by Tokyo Chemical Industry) 4.83 g were mixed at room temperature and stirred for 30 minutes. A titanium-containing liquid mixture was obtained. Ti / the diol = 1/2 (molar ratio).
On the other hand, from 5.0 g of diphenyldimethoxysilane (Ph ₂ Si (OMe) ₂ , manufactured by Shin-Etsu Chemical Co., Ltd.) to 0.37 mL of water, 0.15 mL of 2N aqueous hydrochloric acid, and 5.0 mL of solvent 1-methoxy-2-propanol The resulting solution was added dropwise at room temperature while stirring, and stirring was continued for 1 hour to conduct a hydrolysis reaction to obtain a silicon-containing reaction solution.
The obtained silicon-containing reaction liquid was added to the titanium-containing mixed liquid at room temperature while stirring, and then stirred at 80 ° C. for 1 hour to obtain a mixed solution. Ti / Si = 1/1 (molar ratio).

  To the obtained mixed solution, 0.75 mL of water and 1.5 mL of 1-methoxy-2-propanol were added at room temperature with stirring, and the stirring was continued for 1 hour, followed by further hydrolysis and condensation reaction.

  To the obtained solution, 0.22 g of methacrylic acid (MA) was added at room temperature with stirring, and then stirred at 80 ° C. for 1 hour. Ti / MA = 1 / 0.125 (molar ratio). In this way, a sol solution was obtained.

  Using the obtained sol solution, a hologram recording medium was obtained in the same manner as in Example 1.

In the same manner as in Example 1, the produced hologram recording medium sample was stored at 80 ° C. in a dry environment for 7 days. When infrared spectroscopy was performed in the same manner as in Example 1,
Initial AC = O / Aph = 1.63 / 1
After storage BC = O /Bph=1.10/1
Met. The remaining amount of the photopolymerizable compound after storage was 67.5%.

It is a figure which shows the schematic cross section of the hologram recording medium produced in the Example.

Explanation of symbols

(11): Hologram recording medium
(21): Hologram recording material layer
(22a) (23a): Antireflection film
(22) (23): Glass substrate
(24): Spacer

Claims (9)

A hologram recording material comprising an organic group-containing metal compound and a photopolymerizable compound,
The organic group-containing metal compound contains an oxygen atom and a metal other than Si and Si as a metal, and has a metal-oxygen-metal bond,
A hologram recording material in which at least a part of oxygen atoms not forming the metal-oxygen-metal bond is capped with (meth) acrylic acid.   The hologram recording material according to claim 1, wherein the metal other than Si is selected from the group consisting of Ti, Zr, Ta, Sn, Al, and Zn.   The hologram recording material according to claim 1, wherein the organic group-containing metal compound includes a multidentate ligand coordinated to the metal.   The hologram recording material according to claim 3, wherein the multidentate ligand is selected from the group consisting of a β-dicarbonyl compound, a polyhydroxylated ligand, and an α- or β-hydroxy acid.   The hologram recording material according to claim 1, wherein the photopolymerizable compound is selected from (meth) acrylic acid esters.   Furthermore, the hologram recording material of any one of Claims 1-5 containing a photopolymerizable initiator.   The hologram recording material according to claim 1, wherein the organic group-containing metal compound has an organometallic unit in which two aromatic groups are directly bonded to Si.   A hologram recording medium having a hologram recording layer made of the hologram recording material according to claim 1.   The hologram recording medium according to claim 8, which is recorded / reproduced by a laser beam having a wavelength of 350 to 450 nm.

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