JP2005107235A - Hologram recording material, hologram recording medium and method for manufacturing hologram recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hologram recording material which ensures sufficiently high diffraction efficiency, a hologram recording medium using the same, and a method for manufacturing the hologram recording medium. <P>SOLUTION: The hologram recording medium 1 has a structure in which a recording layer 102 is held between a substrate 101 and a protective layer 103. The recording layer 102 comprises the hologram recording material containing a polysilsesquioxane of formula: (R<SP>1</SP>SiO<SB>1.5</SB>)<SB>n</SB>(where n is an integer of ≥4, R<SP>1</SP>is H or an organic group and a plurality of symbols R<SP>1</SP>may be the same or different), an organic compound whose refractive index is different from that of a polymer of the polysilsesquioxane, and a photo-anionic polymerization initiator. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a hologram recording material, a hologram recording medium, and a method for manufacturing a hologram recording medium.

  In recent years, a method using a holography technique for recording interference fringes caused by light interference has attracted attention as a recording means capable of achieving a larger capacity than a conventional optical recording medium. In this method, for example, a recording material that causes a change in refractive index in accordance with the intensity of irradiated light is used, and interference fringes are recorded as a refractive index distribution that corresponds to the intensity distribution of the light. To record. The interference fringes thus recorded are generally called holograms.

  A hologram recording material that performs recording utilizing the above-described change in refractive index is required to have a high diffraction efficiency. The diffraction efficiency indicates the proportion of light that is effectively used to reproduce a reproduced image in the irradiated reproduction light. That is, the higher the diffraction efficiency, the brighter the reproduced image is obtained and recorded. Information can be read with high reproducibility. The diffraction efficiency tends to be higher as the recording material has a larger change in the refractive index corresponding to the intensity of the irradiated light.

As a recording material that causes such a change in refractive index, there is known a photosensitive composition for holograms composed of a hybrid inorganic organic three-dimensional matrix and a photoactive monomer (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 11-344917

  When the inventor actually produced a hologram recording medium using the photosensitive composition for hologram as disclosed in Patent Document 1 and irradiated it with light, a sufficiently high diffraction efficiency could not be obtained and information was reproduced with good reproducibility. It was difficult to read out. The cause was thought to be due to the small difference in refractive index caused by the polymerization of the photosensitive composition.

  The present invention has been made in view of such circumstances, and provides a hologram recording material capable of obtaining sufficiently high diffraction efficiency, a hologram recording medium using the same, and a method for producing such a hologram recording medium. For the purpose.

The hologram recording material according to the present invention includes a polysilsesquioxane having a structure of (R ¹ SiO _1.5 ) _n , an organic compound having a refractive index different from that of a polymer of polysilsesquioxane, and initiation of photoanionic polymerization. And an agent.

The hologram recording medium according to the present invention has a base and a recording layer formed on the base, and the recording layer is a polysilsesquioxane having a structure of (R ¹ SiO _1.5 ) _n. And an organic compound having a refractive index different from that of the polymer of polysilsesquioxane, and a photoanionic polymerization initiator.

A hologram recording medium according to the present invention is a hologram recording medium comprising a substrate and a hologram recording layer formed on the substrate and having interference fringes recorded thereon. ¹ SiO _1.5 ) a polymer obtained by polymerizing polysilsesquioxane having a structure of _n by irradiating light in the presence of a photoanionic polymerization initiator, and an organic having a refractive index different from that of the polymer. It is characterized by containing a compound.

In addition, the method for producing a hologram recording medium according to the present invention includes a polysilsesquioxane having a structure of (R ¹ SiO _1.5 ) _n and an organic material having a different refractive index from a polymer of polysilsesquioxane. A dissolving step of dissolving a compound and a photoanionic polymerization initiator in an organic solvent, a polysilsesquioxane, an organic compound having a refractive index different from that of the polysilsesquioxane polymer, and a photoanionic polymerization initiator. And an application step of applying the dissolved organic solvent to one side of the substrate.

Here, in (R ¹ SiO _1.5 ) _n , n is an integer of 4 or more, R ¹ is a hydrogen atom or an organic group, and R ¹ may be the same or different.

  In the hologram recording material, hologram recording medium, and hologram recording medium manufacturing method of the present invention, polysilsesquioxane, a polysilsesquioxane polymer, an organic compound having a different refractive index, and photoanionic polymerization The initiator is uniformly dispersed. When a part of the hologram recording material is irradiated with light, a polymerization reaction of polysilsesquioxane occurs due to the photoanion polymerization initiator in the light irradiation part. A polymer is formed. In order to compensate for the polysilsesquioxane consumed by the polymerization reaction, movement / diffusion occurs from the adjacent unirradiated part to the light irradiated part where the polymerization reaction occurs. For this reason, the polymerization of polysilsesquioxane is further promoted.

  On the other hand, an organic compound having a different refractive index from the polymer of polysilsesquioxane in the light-irradiated region was extruded by polymerizing polysilsesquioxane, and polysilsesquioxane was consumed. , Move to adjacent unirradiated part. That is, the polysilsesquioxane polymer and the polysilsesquioxane polymer and organic compounds having different refractive indexes are phase-separated in a microscopic region. Therefore, when the interference fringes formed by superimposing the image information and the reference light on this medium are exposed, the polysilsesquioxane polymer portion having a high polysilsesquioxane polymer concentration corresponding to the light shading in the medium is detected. A portion having a high concentration of an organic compound having a refractive index different from that of the Sun polymer is formed, and interference fringes are recorded. When reference light is applied to such a medium, image information can be reproduced by a diffraction effect generated from a difference in refractive index based on the difference in composition.

  Here, since polysilsesquioxane efficiently generates a polymerization reaction due to the presence of a photoanion polymerization initiator, the polymerization rate also changes greatly corresponding to the change in the intensity of light, and each component accompanying this changes. The amount of movement also increases. As a result, the difference in composition that occurs in response to the interference fringes becomes very clear, which increases the refractive index difference in the hologram recording material on which the interference fringes are recorded, resulting in extremely high diffraction efficiency. It becomes like this.

  In addition, since polysilsesquioxane has a hydrogen atom or an organic group on its surface before light irradiation, it exhibits organic properties, and this polysilsesquioxane and polysilsesquioxane polymer are different in refractive index. Good compatibility with organic compounds. For this reason, in the hologram recording material before light irradiation, it is extremely easy to uniformly disperse polysilsesquioxane, a polysilsesquioxane polymer and an organic compound having a different refractive index, and has excellent transparency. A recording material is obtained.

  In addition, due to the organic properties of polysilsesquioxane, polysilsesquioxane is easily dissolved in an organic solvent. For this reason, when the polysilsesquioxane polymer and the organic compound having different refractive indexes are mixed, they can be well dispersed with an organic solvent without using water. Therefore, the recording material of the present invention is particularly suitable for a hologram recording material that dislikes the remaining of water. The remaining water generates gas such as water vapor when irradiated with light, and bubbles are generated. Since the bubbles diffusely reflect incident light, the function of the recording medium may be lost. Usually, a method for manufacturing a hologram recording medium requires a sufficient dehydration step. According to the production method of the present invention, since no water is used, such a dehydration step is not required, and a method for producing a hologram recording medium with a relatively small number of steps can be provided. In addition, since no water remains in the manufactured recording medium, a highly reliable recording medium can be provided. Further, by preparing a liquid in which polysilsesquioxane is dissolved in an organic solvent, it can be easily applied on the substrate, and a uniform film can be formed on the substrate.

  Furthermore, since this polysilsesquioxane can be regarded as a kind of monomer having a silicon and oxygen skeleton, this monomer becomes a polymer of polysilsesquioxane after light irradiation, and this polysilsesquioxane The polymer of sesquioxane is a metal oxide having a three-dimensional network structure formed by silicon and oxygen serving as a network former. Therefore, the surface of the polysilsesquioxane polymer formed by light irradiation exhibits strong inorganic properties, and the compatibility between the polysilsesquioxane polymer and the organic compound having a different refractive index is deteriorated. . As a result, after the polymerization, the polysilsesquioxane polymer and the polysilsesquioxane polymer and the organic compound having a different refractive index are easily phase-separated in a microscopic region, and the difference in composition is further increased. The difference in refractive index is further increased. Therefore, the diffraction efficiency of the hologram recording medium can be made extremely high. As described above, polysilsesquioxane has a characteristic that its surface properties can be greatly changed from an organic property to an inorganic property before and after polymerization.

  Specifically, the molecular weight of polysilsesquioxane is preferably 300 to 10,000. When the molecular weight of the polysilsesquioxane is less than 300 or exceeds 10,000, the polysilsesquioxane is not polymerized favorably, and there is a tendency that hologram recording cannot be suitably performed.

  The polysilsesquioxane structure may be either amorphous or crystalline, as long as it forms a network polymer composed of silicon and oxygen.

In addition, each R ¹ of the polysilsesquioxane is a hydrogen atom, an optionally substituted alkyl group having 1 to 5 carbon atoms, or an optionally substituted unsaturated carbon atom having 1 to 5 carbon atoms. A hydrogen group, an optionally substituted alkoxy group having 1 to 3 carbon atoms, an optionally substituted phenyl group, and an optionally substituted cyclic hydrocarbon having 5 or 6 carbon atoms It is preferably any group selected from the group consisting of groups. As a result, the compatibility between the polysilsesquioxane and the polysilsesquioxane polymer and the organic compound having a different refractive index is improved, so that a highly transparent hologram recording medium can be produced. .

  Here, the organic compound having a refractive index different from that of the polymer of polysilsesquioxane is preferably a thermoplastic resin. According to this, after light irradiation, the polymer of polysilsesquioxane and the polymer of polysilsesquioxane and the organic compound having a different refractive index are smoothly separated in a microscopic region, and higher. Diffraction efficiency can be obtained.

  Furthermore, it is preferable that an organic compound having a refractive index different from that of a polymer of polysilsesquioxane has a lower polymerization reactivity with a photoanionic polymerization initiator than polysilsesquioxane. According to this, the polysilsesquioxane is polymerized at a higher polymerization rate than the organic compound having a refractive index different from that of the polymer of polysilsesquioxane in the light irradiation portion, and the polymer of polysilsesquioxane is polymerized. Since organic compounds with different refractive indexes are efficiently pushed out from the light-irradiated part and moved to the non-irradiated part, the difference in composition between the light-irradiated part and the non-irradiated part becomes sufficiently large, and the diffraction efficiency should be made higher. Can do.

  Here, the photoanion polymerization initiator is preferably a photobase generator that generates a base by irradiation with light. Thereby, the polymerization reaction of polysilsesquioxane occurs more efficiently.

  According to the present invention, since a hologram recording medium having high diffraction efficiency can be obtained, the hologram recording medium of the present invention can be used as a recording medium having a high recording density and excellent reproducibility. In addition, by using the manufacturing method of the present invention, the number of processes can be reduced, and since the process of adding water is not included in the process, the manufactured recording medium is also reliable without water remaining. A high-quality recording medium can be provided.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described in detail with reference to the drawings. Further, the positional relationship such as up, down, left and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  The hologram recording material according to the present invention contains polysilsesquioxane, an organic compound having a refractive index different from that of the polymer of polysilsesquioxane, and a photoanionic polymerization initiator, and these are uniformly dispersed. Yes. First, polysilsesquioxane will be described.

Polysilsesquioxane is a compound in which silicon and oxygen are bonded to each other, and can be represented by a chemical formula of (R ¹ SiO _1.5 ) _n . Here, n is an integer of 4 or more, R ¹ is a hydrogen atom or an organic group, and R ¹ may be the same or different.

Specifically, as R ¹ of the polysilsesquioxane, a hydrogen atom, an alkyl group having 1 to 5 carbon atoms which may have a substituent, or an alkyl group having 1 to 5 carbon atoms which may have a substituent. A saturated hydrocarbon group, an alkoxy group having 1 to 3 carbon atoms which may have a substituent, a phenyl group which may have a substituent, and a cyclic group having 5 or 6 carbon atoms which may have a substituent It is preferably any group selected from the group consisting of hydrocarbon groups. As a result, the compatibility between the polysilsesquioxane and the polysilsesquioxane polymer and the organic compound having a different refractive index is improved, and the hologram recording material is excellent in transparency.

ここで、上記一般式（２）中、ｍは２以上の整数であり、上記一般式（３）中、ｌは４以上の整数である。 The molecular structure of such polysilsesquioxane is not particularly limited as long as it has a network polymer formed of silicon and oxygen. Polysilsesquioxane usually exists in an amorphous form and has a molecular structure without ordering. Therefore, the chemical structure may be amorphous or crystalline. Moreover, this silsesquioxane may take the form of a ladder like the following general formula (2) or a saddle shape like the general formula (3) depending on the case.

Here, in the general formula (2), m is an integer of 2 or more, and in the general formula (3), l is an integer of 4 or more.

The ladder of polysilsesquioxane of formula (2), for example, and a -CH ₃ and -C ₆ H ₅ as R ^1, the molar ratio of the -CH ₃ and -C ₆ H ₅ is GR (glass resin) 100 which is 2: 1, GR650 in which R ¹ is all —CH ₃ , and —CH ₃ and —C ₆ H ₅ as R ¹ , —CH ₃ and —C ₆ H ₅ GR908 having a molar ratio of 1: 4, GR950 having all R ¹ of -C ₆ H ₅ (both manufactured by Showa Denko KK), and the like. Examples of the cage-shaped polysilsesquioxane of the general formula (3) include polycyclohexylsilsesquioxane, polycyclopentylsilsesquioxane, and the like.

In the general formulas (2) and (3), R ¹ is preferably a hydrogen atom. When R ¹ is a hydrogen atom, Si-H is hydrolyzed to Si-OH by an anionic active species such as a base generated from a photoanionic polymerization initiator during light irradiation due to the ease of the reaction. . Thereafter, a polysilsesquioxane polymer is easily obtained by dehydration condensation.

In particular, among the molecular structures of the cage-shaped polysilsesquioxane of the general formula (3), n is 4 and R ¹ is all hydrogen atoms. The silsesquioxane of the general formula (1) (T ₈ cube) ) Is preferable because it is a three-dimensional structure having a cubic structure and is excellent in polymerizability.

  Moreover, it is preferable that the molecular weights of polysilsesquioxane are 300-10000. When the molecular weight of polysilsesquioxane is less than 300, shrinkage tends to occur during polymerization, and there is a tendency that it is difficult to suitably perform hologram recording. On the other hand, if it exceeds 10,000, the compatibility with organic compounds having different refractive indexes or the solubility in a solvent deteriorates, and there is a tendency that hologram recording cannot be suitably performed. In particular, in the polysilsesquioxane of the general formula (1), the total molecular weight is more preferably 1000 to 8000.

上記一般式（４）中、R²はフェニル基、炭素数１０以下のアルキル基又はアリル基のうちのいずれかの置換基、R³は炭素数４以下のアルキル基であって、各々同一でも異なっていてもよい。 Such a polysilsesquioxane can be obtained, for example, by hydrolyzing the silicon compound of the general formula (4) by stirring in a solvent such as alcohol for several hours and adding a solvent such as water or hexane. .

In the general formula (4), R ² is a phenyl group, a substituent of any one of an alkyl group having 10 or less carbon atoms or an allyl group, and R ³ is an alkyl group having 4 or less carbon atoms, May be different.

  Next, an organic compound having a refractive index different from that of the polysilsesquioxane polymer contained in the hologram recording material of the present invention will be described.

上記一般式（５）中、R⁴は炭素数１〜４のアルキル基、MはTi、Sn、Inから選択される金属である。 The organic compound having a refractive index different from that of the polymer of polysilsesquioxane is compatible with polysilsesquioxane, an organic compound that can be uniformly dispersed when used as a hologram recording material, and Any organic compound having a refractive index different from that of the polymer of polysilsesquioxane can be used without particular limitation. For example, chlorinated polyethylene, polymethyl methacrylate, copolymers of methyl methacrylate and other (meth) acrylic acid alkyl esters, copolymers of vinyl chloride and acrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone , Ethyl cellulose, acetyl cellulose and the like. Moreover, an acetylacetone derivative as represented by the general formula (5) may be used.

In the general formula (5), R ⁴ is an alkyl group having 1 to ⁴ carbon atoms, and M is a metal selected from Ti, Sn, and In.

  Here, the organic compound having a refractive index different from that of the polymer of polysilsesquioxane is preferably a thermoplastic resin such as vinyl chloride, styrene, or an acrylic compound. According to this, after the light irradiation, the polysilsesquioxane polymer and the polysilsesquioxane polymer and the organic compound having a different refractive index are smoothly separated in a microscopic region, and thus higher. Diffraction efficiency can be obtained. Examples of the acrylic compound include polymethyl methacrylate.

  Such an organic compound having a refractive index different from that of the polymer of polysilsesquioxane may be a monomer or a polymer. In the case of a polymer, the number average molecular weight is preferably 2000 to 100,000. At this time, if the number average molecular weight of the polymer is less than 2000, the heat resistance of the hologram recording medium is lowered, and if the number average molecular weight of the polymer is more than 100,000, the solubility in a solvent is deteriorated, resulting in recording for hologram. There is a tendency that the production of the medium becomes difficult.

  The organic compound having a refractive index different from that of the polymer of polysilsesquioxane is preferably lower in polymerization reactivity with a photoanion polymerization initiator described later than polysilsesquioxane. According to this, the polysilsesquioxane is polymerized at a higher polymerization rate than the organic compound having a refractive index different from that of the polymer of polysilsesquioxane in the light irradiation portion, and the polymer of polysilsesquioxane is polymerized. Since organic compounds with different refractive indexes are efficiently pushed out from the light-irradiated part and moved to the non-irradiated part, the difference in composition between the light-irradiated part and the non-irradiated part becomes sufficiently large, and the diffraction efficiency should be made higher. Can do.

  Next, the photoanionic polymerization initiator contained in the hologram recording material of the present invention will be described.

  A photoanionic polymerization initiator is a component that can generate an anionic active species that accelerates the polymerization of the above polysilsesquioxane when irradiated with light. For example, it generates a base when irradiated with light. A photobase generator can be illustrated. In this case, either a nonionic photobase generator that generates a nonionic base or an ionic photobase generator that generates an ionic base can be preferably used.

  First, as the nonionic photobase generator, a compound capable of generating an amine upon irradiation with light is preferable. Examples of such a compound include acyl oxime, carbamoyl oxime, carbamic acid derivative, formamide and the like.

式中、Ｒ^３１、Ｒ^３２及びＲ^３３はそれぞれ独立に炭素数１〜５のアルキル基、炭素数５〜７のシクロアルキル基又は炭素数６〜２０のアリール基を示す。より具体的には、Ｒ^３１がフェニル基、Ｒ^３２がメチル基及びＲ^３３がフェニル基である組み合わせ、Ｒ^３１がベンジル基、Ｒ^３２がメチル基及びＲ^３３が−Ｃ_１０Ｈ_７で表される基である組み合わせを有するアシルオキシムが好適である。 Specifically, the acyloxime is preferably a compound represented by the following formula (6).

In formula, R <^31> , R ^<32> and R ^<33 > show a C1-C5 alkyl group, a C5-C7 cycloalkyl group, or a C6-C20 aryl group each independently. More specifically, a combination in which R ³¹ is a phenyl group, R ³² is a methyl group and R ³³ is a phenyl group, R ³¹ is a benzyl group, R ³² is a methyl group, and R ³³ is represented by —C ₁₀ H _7. Acyl oximes having combinations that are groups are preferred.

式中、Ｒ^３１、Ｒ^３２及びＲ^３３は上記と同義である。かかるカルバモイルオキシムとしては、Ｒ^３１がフェニル基、Ｒ^３２がメチル基及びＲ^３３がフェニル基である組み合わせ、Ｒ^３１がシクロヘキシル基、Ｒ^３２及びＲ^３３がフェニル基である組み合わせ、Ｒ^３１がシクロヘキシル基、Ｒ^３２がフェニル基及びＲ^３３がメチル基である組み合わせのものが特に好ましい。 Moreover, as carbamoyl oxime, the compound represented by following formula (7) is preferable.

In the formula, R ³¹ , R ³² and R ³³ are as defined above. Such carbamoyloximes include a combination in which R ³¹ is a phenyl group, R ³² is a methyl group and R ³³ is a phenyl group, a combination in which R ³¹ is a cyclohexyl group, R ³² and R ³³ are a phenyl group, and R ³¹ is a cyclohexyl group. A combination in which R ³² is a phenyl group and R ³³ is a methyl group is particularly preferable.

Furthermore, as the carbamine derivative, compounds represented by the following formulas (8a) to (8c) are preferable, and as the formamide, a compound represented by the following formula (9) is preferably used.

In addition to these photoanionic polymerization initiators, when a compound that generates an amine by heat is combined, the amount of base produced is greatly improved, and the polymerization efficiency can be further increased. Examples of the compound that generates an amine by such heat include compounds represented by the following formula (10a) or (10b).

式（１１ｄ）中、Ｒ^８１は、炭素数１〜５のアルキル基、炭素数５〜７のシクロアルキル基又は炭素数６〜２０のアリール基、Ｙ⁻はＢｒ⁻又は（ＣＨ_３）_２ＮＣ（＝Ｓ）Ｓ⁻で表される基を示す。ここで、Ｒ^８１としては、フェニル基又はＣ_１０Ｈ_７で表される基がより好ましい。 On the other hand, as the ionic photobase generator, a compound capable of generating an amine upon irradiation with light is preferable. Examples of such ionic photobase generators include compounds represented by the following formulas (11a) to (11d).

In formula (11d), R ⁸¹ represents an alkyl group having 1 to 5 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or an aryl group having 6 to 20 carbon atoms, Y ⁻ represents Br ⁻ or (CH ₃ ) ₂ NC. (= S) S ^- represents a group represented by. Here, as R ⁸¹ , a phenyl group or a group represented by C ₁₀ H ₇ is more preferable.

Examples of the photoanionic polymerization initiator include a compound represented by the following formula (12a) or (12b) that generates a hydroxyl group by light irradiation, and a formula (13) that generates 1,6-dimethylpiperidine. Can be used.

上記式中、ａｃａｃはアセチルアセトネート、Ａｎはアントラセン、Ｍはクロム又はタングステン、Ｌはピロリジン、ビニルピリジンを示す。これらの化合物は、光の照射によりＮＣＳ⁻、ａｃａｃ⁻、Ｃ_６Ｈ_５ＣＯＯ⁻、ピリジン及びピリジン誘導体等のアニオン活性種を発生させる。 In addition, compounds represented by the following formulas (14a) to (14e) can be used.

In the above formula, acac is acetylacetonate, An is anthracene, M is chromium or tungsten, L is pyrrolidine, vinylpyridine. These compounds generate anion-active species such as NCS ⁻ , acac ⁻ , C ₆ H ₅ COO ⁻ , pyridine, and pyridine derivatives when irradiated with light.

式中、Ｒ^１２１、Ｒ^１２２及びＲ^１２３はそれぞれ独立に炭素数１〜５のアルキル基、炭素数５〜７のシクロアルキル基、炭素数６〜２０のアリール基を示す。Ｒ^１２２及びＲ^１２３としては、メチル基又はフェニル基が特に好ましい。 The photoanionic polymerization initiator is not limited to the above-described low molecular weight compound, and a high molecular weight photoanionic polymerization initiator can be used. Examples of such a polymer photoanion polymerization initiator include a polymer compound incorporating an acyloxyimino group or a carbamoyloxyimino group, which is a structural unit composed of acyloxime or carbamoyloxime, which is a low molecular weight photoanion polymerization initiator. . Specifically, for example, compounds represented by the following formulas (15a) to (15c) can be exemplified.

In the formula, R ¹²¹ , R ¹²² and R ¹²³ each independently represent an alkyl group having 1 to 5 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or an aryl group having 6 to 20 carbon atoms. R ¹²² and R ¹²³ are particularly preferably a methyl group or a phenyl group.

As such a polymer photoanionic polymerization initiator, it has both a structural unit that generates a base by light and a structural unit that generates an acid by light, as represented by the following formula (16). Such an initiator can also be used, and it can be suitably used when it is necessary to control the solubility in a solvent.

Moreover, the compound which can function as a photoanion polymerization initiator by using 2 or more types of compounds in combination can also be used as an initiator. Examples of such a combination include a combination of the following formula (17a) and the following formula (17b).

  In such a hologram recording material, the polysilsesquioxane, the polysilsesquioxane polymer, an organic compound having a different refractive index, and the total weight of the photoanionic polymerization initiator are combined with the polysilsesquioxane. 20 to 80% by weight of rusesquioxane, 20 to 80% by weight of an organic compound having a refractive index different from that of the polysilsesquioxane polymer, and 0.05 to 20% by weight of a photoanionic polymerization initiator preferable. By setting such a weight ratio, polysilsesquioxane can be efficiently polymerized at the time of recording, and a large difference in composition can be caused. As a result, the difference in refractive index is increased and higher diffraction efficiency can be obtained.

  The hologram recording material of the present invention may contain other components such as a sensitizer and a plasticizer to the extent that the hologram recording is not affected in addition to the above-described essential components. For example, sensitizers that accelerate polymerization of polysilsesquioxane by light include thiopyrylium salt dyes, merocyanine dyes, quinoline dyes, styrylquinoline dyes, ketocoumarin dyes, thioxanthene dyes, xanthene dyes. And oxonol dyes, cyanine dyes, rhodamine dyes, pyrylium salt dyes, and the like. As these sensitizers, those which become colorless by applying a predetermined treatment after hologram recording are particularly desirable. Examples of the plasticizer include dibutyl phthalate and d4 silicone.

  Further, as another component, for example, when a film made of a hologram recording material is formed, a binder such as an acrylic resin can be contained for the purpose of improving the strength of the film.

  Next, the hologram recording medium according to the present invention will be described.

  FIG. 1 is a cross-sectional view schematically showing a hologram recording medium of the present invention. A hologram recording medium 1 includes a substrate 101, a recording layer 102 made of the hologram recording material of the present invention formed on the substrate, and a protective layer 103 formed on the substrate and protecting the recording layer. It has. Note that the hologram recording medium 1 does not necessarily have the protective layer 103, and a hologram recording medium of the present invention includes a two-layer structure including the base 101 and the recording layer 102.

  The substrate 101 or the protective layer 103 used in the hologram recording medium is not particularly limited as long as it is formed from a material having transparency to light used for hologram recording. Examples of such a transparent substrate include a plate substrate such as a glass substrate, an acrylic plate, and a polycarbonate plate, and a film such as polyethylene (PE), polypropylene (PP), polynaphthalene, and polyethylene terephthalate film (PET). The upper base material etc. are mentioned. As long as recording from one surface of the hologram recording medium 1 is performed, it is not always essential that both the base 101 and the protective layer 103 are made of these transparent substrates, and either one is transparent. Hologram recording can be performed.

  Next, a method for producing such a hologram recording material and hologram recording medium 1 will be described.

  In the method for producing the hologram recording medium 1 according to the present invention, mainly, a dissolution step of dissolving the constituent components of the hologram recording material in an organic solvent to obtain a coating solution, and the obtained coating solution on one side of the substrate. And an application process for removing the organic solvent from the applied solution.

  First, the dissolution process will be described. Here, the above-mentioned polysilsesquioxane, an organic compound having a refractive index different from that of the polysilsesquioxane polymer, and a photoanionic polymerization initiator are dissolved in an organic solvent to obtain a coating solution. Here, examples of the organic solvent include acetone, tetrahydrofuran, ethyl acetate, isopropanol, ethanol, methanol, dichloromethane, and chloroform. Among these, acetone having good volatility is preferable in view of the cost and the solvent removal step after the dissolution step.

  Subsequently, in the coating process, the coating solution thus obtained is coated on one side of the substrate 101 described above. As a coating method, various methods such as a method using a doctor blade and an applicator can be applied in addition to spin coating, dip coating, flow coating (curtain coating) and the like.

  Subsequently, in the solvent removal step, the recording layer 102 is formed by removing the organic solvent at room temperature or in a heated state, and if necessary, under a reduced pressure. The hologram recording medium 1 can be obtained by depositing the protective layer 103 on the recording layer 102.

  Not limited to the above-described manufacturing method, a solution containing a hologram recording material is filled in a die using the base 101 and the protective layer 103 as parallel plates, and then bonded between the base 101 and the protective layer 103 by pressure bonding. The hologram recording medium 1 can also be manufactured by the method of forming the recording layer 102 on the substrate.

  Next, a hologram recording method and recording principle using the hologram recording medium 1 of the present invention will be described, and a recording medium on which interference fringes according to the present invention are recorded will be described.

  First, light having the information to be recorded (object light) and light having no information (reference light) are irradiated to the same position of the hologram recording material from different angles. When this object light and reference light are irradiated, active species are generated from the photoanionic polymerization initiator at the irradiated site, thereby dehydrating condensation of polysilsesquioxanes present near the active species, and the irradiated site. Then, a polymer of polysilsesquioxane is formed. In this case, since the polysilsesquioxane consumed by the polymerization reaction is compensated, the movement / diffusion of the polysilsesquioxane may occur from the peripheral portion where the light intensity is weaker to the portion where the polymerization reaction occurs. become. At the same time, the organic compound having a refractive index different from that of polysilsesquioxane is pushed out from the site where the polymerization reaction occurs as the polysilsesquioxane moves, leading to a site where the light intensity is weaker. Moving.

  Due to such movement / diffusion, the recording material has a high concentration of polysilsesquioxane polymer corresponding to the intensity of the irradiated light, and the polysilsesquioxane polymer is refracted. Regions in which organic compounds having different rates exist at high concentrations are formed, and a difference in composition occurs between these regions. Here, in the part irradiated with the object light and the reference light, interference fringes are formed by the interference of the two lights. Therefore, the difference in composition between the respective regions corresponds to the intensity of light due to interference fringes. In this case, in the hologram recording material, a difference in refractive index is formed between the regions based on the difference in composition generated corresponding to the intensity of light due to the interference fringes. Thus, the interference fringes are recorded as a difference in refractive index generated in the recording material.

  In the hologram recording medium 1, interference fringes are thus recorded, and a hologram recording medium on which predetermined information is recorded is obtained. The hologram recording medium after recording is composed of a base and a hologram recording layer formed on the base. The hologram recording layer in such a recording medium comprises a polysilsesquioxane polymer obtained by polymerizing polysilsesquioxane by irradiating light in the presence of a photoanionic polymerization initiator, and the polysilsesquioxane. It contains an organic compound having a refractive index different from that of an oxan polymer. In such a recording layer, a predetermined distribution occurs in the composition ratio between the polysilsesquioxane polymer and the polysilsesquioxane polymer and the organic compound having a different refractive index, as described above. The interference fringes are recorded by a predetermined distribution of the composition ratio.

  The information recorded on the hologram recording medium in this way is irradiated with the same light as the reference light used for recording, and the irradiated light is diffracted by the hologram. It can be read out by reproducing.

  According to the hologram recording material, the hologram recording medium 1 and the method for producing the hologram recording medium 1 of the present invention, for example, the following operations and effects can be obtained.

  In other words, since polysilsesquioxane efficiently generates a polymerization reaction due to the presence of a photoanionic polymerization initiator, the polymerization rate changes greatly in response to changes in light intensity, and the movement of each component accompanying this changes. The amount also increases. As a result, the difference in composition that occurs in response to the interference fringes becomes very clear, which increases the refractive index difference in the hologram recording material on which the interference fringes are recorded, resulting in extremely high diffraction efficiency. It becomes like this.

  In addition, the polysilsesquioxane in the hologram recording material of the present invention has an organic property because it has a hydrogen atom or an organic group on its surface before light irradiation. This polysilsesquioxane and the polysilsesquioxane, Good compatibility between an oxane polymer and an organic compound having a different refractive index. Therefore, a hologram recording material that can be uniformly dispersed in an organic solvent and is excellent in transparency can be obtained.

  Furthermore, polysilsesquioxane is polymerized after light irradiation to become a polymer of polysilsesquioxane. Such a polymer of polysilsesquioxane is a metal oxide having a three-dimensional network structure formed by silicon and oxygen serving as a network former, and therefore has a strong inorganic property. Therefore, after light irradiation, the polysilsesquioxane polymer and the polysilsesquioxane polymer and the organic compound having a different refractive index are easily phase-separated in a microscopic region. Therefore, the difference in composition corresponding to the interference fringes becomes even larger, and the diffraction efficiency of the hologram recording medium can be further increased significantly.

  Thus, according to the present invention, a hologram recording medium having high diffraction efficiency can be obtained. Therefore, the hologram recording medium of the present invention can be used as a recording medium having a high recording density and excellent reproducibility.

  Further, in such a method for producing the hologram recording medium 1, polysilsesquioxane is easily dissolved in an organic solvent. For this reason, it is not necessary to use water in the dissolving step, and water hardly remains in the manufactured recording medium.

  Here, if water remains, a gas such as water vapor is generated during light irradiation, and bubbles are generated. Since the bubbles diffusely reflect incident light, the function of the recording medium may be lost. However, in the method for manufacturing a hologram recording medium of the present invention, manufacturing is performed without adding water in the process. Thus, no water remains on the recorded recording medium, and a highly reliable recording medium can be provided.

  In addition, since the dehydration step is unnecessary, it is possible to manufacture the hologram recording material and the hologram recording medium at a low cost.

  Furthermore, by preparing a coating solution in which the constituents of the hologram recording material are dissolved in an organic solvent, the coating on the substrate 101 can be easily performed, and a uniform film can be formed on the substrate. Become.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(Example 1)
First, 50 parts by weight of polyhydridosilsesquioxane (SST-H8H01, manufactured by Azmax Co.) as polysilsesquioxane, and 2-hydroxy- 50 parts by weight of 3-phenoxypropyl acrylate, 5 parts by weight of 1,2,6-trimethyl-4- (2-nitrophenyl) -1,4-dihydropyridine-3,5-dicarboxylic acid dimethyl ester as a photoanionic polymerization initiator 1 part by weight of 3,3′-carbamylbis-7-diethylaminocoumarin was prepared as a sensitizer and dissolved in 100 parts by weight of acetone. Next, a polyethylene terephthalate film with a thickness of 50 μm is attached to both ends of the slide glass as a spacer, and the above mixture is dropped onto the center of the slide glass (the region sandwiched between the spacers) and dried under reduced pressure for 24 hours to form a recording layer. did. Thereafter, a slide glass was applied to produce a hologram recording medium.

The hologram recording medium thus obtained was subjected to two-beam interference exposure using the apparatus shown in FIG. 2 to record a hologram. The medium 1 was subjected to two-beam interference exposure with an exposure power density of 5 mW / cm ² using a doubled-YAG laser 2 (λ = 532 nm). The light emitted from the YAG laser 2 is split into two by a half mirror 4 through a beam expander 3, and irradiated onto the medium 1 through mirrors 5 and 6, respectively. The interference fringes of both lights are recorded on the hologram recording medium 1. Holograms were formed by recording on the layer. Here, the shutter 7 between the half mirror 4 and the mirror 5 and the neutral density filter 8 between the beam expander 3 and the half mirror 4 were not used.

  After recording, the amount of light is reduced by using a neutral density filter 8 and the shutter 7 between the half mirror 4 and the mirror 5 is operated to reproduce the hologram by irradiating only the reference light from the YAG laser 2 onto the medium 1. did. Then, the diffraction efficiency was evaluated by detecting the reproduction light with the photodetector 10. The diffraction efficiency obtained thereby was 41%.

(Comparative Example 1)
First, 50 parts by weight of polyhydridosilsesquioxane (SST-H8H01, manufactured by Azmax Co.) as polysilsesquioxane, and 2-hydroxy- 50 parts by weight of 3-phenoxypropyl acrylate and 5 parts by weight of a titanocene derivative (Cibagayki Co., Ltd., IRG-784) as a photo radical initiator were prepared and dissolved in 100 parts by weight of acetone. Otherwise, the hologram recording medium of Comparative Example 1 was produced in the same manner as in the Example. The diffraction efficiency obtained thereby was 28%. In this case, 2-hydroxy-3-phenoxypropyl acrylate was polymerized rather than polysilsesquioxane.

(Comparative Example 2)
First, 50 parts by weight of polyhydridosilsesquioxane (SST-H8H01, manufactured by Asmax Co.) as polysilsesquioxane, and 50 titanium oxide as an inorganic compound having a refractive index different from that of the polymer of polysilsesquioxane. Parts by weight, 5 parts by weight of 1,2,6-trimethyl-4- (2-nitrophenyl) -1,4-dihydropyridine-3,5-dicarboxylic acid dimethyl ester as a photoanionic polymerization initiator, 3 as a sensitizer , 3′-carbamylbis-7-diethylaminocoumarin was prepared in an amount of 1 part by weight and dissolved in 100 parts by weight of acetone. Otherwise, the hologram recording medium of Comparative Example 2 was produced in the same manner as in the Example. At this time, the transparency of the hologram recording medium was not improved. Further, the diffraction efficiency obtained thereby was 5%.

It is sectional drawing of the recording material for hologram concerning this embodiment. This is a device for recording and reproducing holograms using the hologram recording medium 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Hologram recording medium, 101 ... Base | substrate, 102 ... Recording layer (hologram recording material).

Claims (11)

(R ¹ SiO _1.5 ) _n [wherein n is an integer of 4 or more, R ¹ is a hydrogen atom or an organic group, and R ¹ may be the same or different] and a polysilsesquioxane having the structure ,
An organic compound having a different refractive index from the polysilsesquioxane polymer;
A photoanionic polymerization initiator;
A hologram recording material comprising:   The hologram recording material according to claim 1, wherein the polysilsesquioxane has a molecular weight of 300 to 10,000. R ¹ each has a hydrogen atom, an optionally substituted alkyl group having 1 to 5 carbon atoms, an optionally substituted unsaturated hydrocarbon group having 1 to 5 carbon atoms, and a substituent. Selected from the group consisting of an optionally substituted alkoxy group having 1 to 3 carbon atoms, an optionally substituted phenyl group, and an optionally substituted cyclic hydrocarbon group having 5 or 6 carbon atoms. The hologram recording material according to claim 1, which is any group. The hologram recording material according to claim 1, wherein R ¹ is a hydrogen atom. The hologram recording material according to claim 1, wherein the polysilsesquioxane is represented by the general formula (1).

  6. The hologram recording material according to claim 1, wherein the organic compound having a refractive index different from that of the polysilsesquioxane polymer is a thermoplastic resin.   The organic compound having a refractive index different from that of the polymer of polysilsesquioxane is lower in polymerization reactivity with the photoanionic polymerization initiator than the polysilsesquioxane. The hologram recording material as described.   The hologram recording material according to claim 1, wherein the photoanionic polymerization initiator is a photobase generator that generates a base by irradiation with light. A substrate and a recording layer formed on the substrate;
The recording layer has a structure of (R ¹ SiO _1.5 ) _n (where n is an integer of 4 or more, R ¹ is a hydrogen atom or an organic group, and R ¹ may be the same or different). With Rusesquioxane,
An organic compound having a different refractive index from the polysilsesquioxane polymer;
A photoanionic polymerization initiator;
A hologram recording medium comprising: A hologram recording medium comprising: a substrate; and a hologram recording layer formed on the substrate and having interference fringes recorded thereon,
The hologram recording layer has a structure of (R ¹ SiO _1.5 ) _n (where n is an integer of 4 or more, R ¹ is a hydrogen atom or an organic group, and R ¹ may be the same or different). It contains a polymer obtained by polymerizing polysilsesquioxane by irradiating light in the presence of a photoanionic polymerization initiator, and an organic compound having a refractive index different from that of the polymer. Hologram recording medium. (R ¹ SiO _1.5 ) _n [wherein n is an integer of 4 or more, R ¹ is a hydrogen atom or an organic group, and R ¹ may be the same or different] and a polysilsesquioxane having the structure An organic compound having a different refractive index from the polysilsesquioxane polymer and a photoanionic polymerization initiator are dissolved in an organic solvent; and
An application step of applying the organic solvent in which the polysilsesquioxane, an organic compound having a refractive index different from that of the polysilsesquioxane, and the photoanionic polymerization initiator are dissolved, to one side of a substrate;
A method for manufacturing a hologram recording medium, comprising:

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