JP2013182040A - Photopolymer composition for hologram recording, and hologram recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photopolymer composition for hologram recording and a hologram recording medium which are capable of achieving both high recording sensitivity and recording properties.SOLUTION: Provided is a photopolymer composition for hologram recording containing a compound (A) represented by the specified general formula (I), a binder polymer (B), a radical polymerizable compound (C), a cationic polymerizable compound (D), and a radical polymerization initiator system (E). The radical polymerizable compound (C) has a site selected from a group consisting of a sulfur atom not originating from a cyclic sulfide or a mercapto group, an aromatic ring, and a halogen atom except fluorine. Also provided is a hologram recording medium having a recording layer comprising the composition. In the formula (I), R1 is an alkyl group with a main chain having 3 or more carbon atoms, R2 is an organic group other than an aromatic ring, and n is 2 or greater.

Description

  The present invention relates to a hologram recording photopolymer composition and a hologram recording medium having a hologram recording layer comprising the hologram recording photopolymer composition.

  Many hologram recording materials using photosensitive resins have been proposed, and some of them have been put into practical use. The photosensitive resin is generally called a photopolymer, and a hologram recording material made of a photopolymer has a great advantage that it does not require a development process as compared with a conventional silver halide photosensitive material.

  A typical photopolymer material for hologram recording comprises, for example, a photopolymerizable monomer (I), a polymer binder (II), a plasticizer (III), and a photopolymerization initiator (IV). By irradiating a hologram recording material made of a photopolymer material formed in a film shape with recording light on which an interference pattern is superimposed, the interference pattern is recorded as a refractive index difference (refractive index modulation: Δn) in the recording material. Is done. The reaction mechanism in the recording material at this time is considered as follows. That is, upon exposure, the photopolymerization initiator (IV) is cleaved in the bright part of the interference pattern, and the photopolymerizable monomer (I) present in the vicinity is polymerized using this as a trigger. Along with this, the concentration of unreacted monomer decreases in the bright portion, and a monomer concentration gradient occurs between the dark portion and the dark portion. In order to compensate for the generated concentration gradient, unreacted monomer diffuses from the dark part to the bright part, and the polymerization reaction of the monomer further proceeds in the bright part. As a result, a large amount of the photopolymerizable monomer (I) polymer is present in the bright part. At this time, if each component is selected so that the difference in refractive index between the photopolymerizable monomer (I) (and its polymer) and the other components becomes large, the pattern corresponding to the brightness of the light has a refractive index. Recorded as modulation (Δn). However, the stability of holograms recorded using typical photopolymer materials as described above is generally low. This is because the liquid plasticizer (III) that is inactive to the light during hologram recording remains in the recording film after recording.

In Japanese Patent No. 2873126 (Patent Document 1), a component that is sensitive to a cationically polymerizable compound (a), a radically polymerizable compound (b), a laser beam having a specific wavelength, or light having excellent coherence, which is liquid at room temperature. Light radical polymerization initiator system (c) that polymerizes (b) and light that is low in sensitivity to light of the specific wavelength and that polymerizes component (a) by being sensitive to light of another wavelength The said subject is solved by using the photosensitive composition for volume hologram recording containing each component of a cationic polymerization initiator (d).

The average refractive index of component (a) in the publication is lower than the average refractive index of component (b). That is, the component (a) in the publication corresponds to the plasticizer (III). By imparting cationic polymerizability to a liquid plasticizer at room temperature, it can act as a plasticizer that promotes diffusion of the photopolymerizable monomer (I) during recording, while it can be cured by cationic polymerization with ultraviolet light after recording. For this reason, the liquid component does not remain in the recording film after irradiation with ultraviolet light (called post-cure), and the stability of the recording signal is high. However, in the same publication, since the radical initiator system (c) and the photocationic initiator (d) are used in combination, the hologram recording sensitivity is reduced as compared with the case where the radical initiator system (c) is not used (only the radical initiator system (c)). There was a problem to do. That is, since a part of the exposure energy is used for the initiation reaction of the photocationic initiator (d) at the time of hologram recording, the efficiency of the radical reaction is reduced as compared with the case where no cationic initiator is used. Recording sensitivity decreases.

Japanese Patent No. 4157571 (Patent Document 2) provides a hologram recording medium in which the recording sensitivity does not decrease by using a blocked carboxylic acid compound obtained by blocking a carboxylic acid with a vinyl ether compound. The blocked carboxylic acid is decomposed by heat to generate a free carboxyl group, and this carboxyl group reacts with the cationic polymerizable compound and cures, while being inactive to light at the time of hologram recording. Even in a composition using a radical reaction system and a cation reaction system as in Patent Document 1, the hologram recording sensitivity does not decrease.

Japanese Patent No. 2873126 Japanese Patent No. 4155571

When the photopolymer composition made of the material disclosed in Patent Document 1 is used, a liquid component does not remain in the recording film after post-curing, so that the recording signal can be stably maintained. However, on the other hand, there has been a problem that the recording sensitivity is lowered as compared with a photopolymer composition using only a radical reaction system.

Patent Document 2 provides a photopolymer composition in which the recording sensitivity is not lowered even in a composition using both a radical reaction system and a cation reaction system by using a blocked carboxylic acid compound. However, since the cationic polymerization initiator used in Patent Document 1 causes a cationic polymerization reaction once the acid is generated, the addition amount in the total amount of the photopolymer composition may be small (˜3 wt%). Since the curing using the blocked carboxylic acid compound is due to the crosslinking reaction between the carboxyl group liberated by heating and the cation reactive group, the cationic polymerizable compound must be used in order to proceed sufficiently. There was a problem that it was necessary to add an amount corresponding to the amount.

That is, if the amount of the blocked carboxylic acid added to the total amount of the photopolymer composition is increased, the amount of other components (monomer, polymer binder, plasticizer, etc.) is inevitably reduced. For example, if the amount of radical monomer and plasticizer is reduced, the refractive index modulation degree (Δn) at the time of hologram recording is lowered, and if the polymer binder is reduced, the viscosity of the hologram recording film is greatly lowered.

The object of the present invention is to give the blocked carboxylic acid compound a function as a plasticizer (microphase separation function with a monomer) in addition to the function of reacting with a cationic monomer and curing, thereby producing a radical reaction system. Another object of the present invention is to provide a holographic recording photopolymer composition and a holographic recording medium that can achieve both high recording sensitivity and high recording characteristics even in a composition in which a cation reaction system is used in combination.

The present inventors diligently studied, and the blocked carboxylic acid compound having a specific structure has a function as a plasticizer (microphase separation function with a monomer), and even in a coexisting composition of a radical reaction system and a cation reaction system. It was found that both high recording sensitivity and recording characteristics can be achieved.

（Ｉ）

ここで、Ｒ１は主鎖の炭素数が３以上のアルキル基、Ｒ２は芳香環以外の有機基、ｎは２以上である。 The present invention includes the following inventions.
(1) Including a compound (A) represented by the following general formula (I), a binder polymer (B), a radical polymerizable compound (C), a cationic polymerizable compound (D), and a radical polymerization initiator system (E) The photopolymer composition for hologram recording, wherein the radical polymerizable compound (C) has a site selected from the group consisting of a sulfur atom derived from other than a cyclic sulfide and a mercapto group, an aromatic ring, and a halogen atom other than fluorine.

(I)

Here, R1 is an alkyl group having 3 or more carbon atoms in the main chain, R2 is an organic group other than an aromatic ring, and n is 2 or more.

(2) The photopolymer composition for hologram recording according to the above (1), wherein at least a part of the radical polymerizable compound (C) has a 9,9-diarylfluorene skeleton.

(3) A compound in which at least a part of the cationically polymerizable compound (D) has a site selected from the group consisting of a sulfur atom derived from other than a cyclic sulfide and a mercapto group, an aromatic ring, and a halogen atom other than fluorine. The photopolymer composition for hologram recording according to the above (1) to (2).

(4) A hologram recording medium having a base material and a hologram recording layer made of the photopolymer composition for hologram recording according to any one of (1) to (3) formed on the base material.

In the hologram recording material of the present invention, R1 in the general formula (I) is an alkyl group having 3 or more carbon atoms in the main chain, R2 is an organic group other than an aromatic ring, and n is 2 or more. A radically polymerizable compound (C) having a site selected from the group consisting of a compound represented by formula (A) and a sulfur atom derived from other than a cyclic sulfide and a mercapto group, an aromatic ring, and a halogen atom other than fluorine. Including. The compound (A) represented by the general formula (I) is inactive to light at the time of hologram recording, but decomposes by heating to produce a free carboxyl group, which reacts with the cationically polymerizable compound. Therefore, even in a composition in which a radical reaction system and a cation reaction system coexist, the hologram recording sensitivity does not decrease as compared with a composition consisting only of a radical reaction system.

The compound (A) represented by the general formula (I) also has a property as a plasticizer (microphase separation ability with a monomer) because the alkyl group R1 portion has high hydrophobicity. Therefore, even if the amount of the block carboxylic acid added is increased, the amount of the plasticizer can be reduced, and the refractive index modulation degree (Δn) and the fluidity of the recording film are reduced as in the above-mentioned Patent Document (2). Can be prevented. Further, in the present invention, the compound (A) represented by the general formula (I) generally has a low refractive index because it does not have an aromatic ring known for its high refractive index in the R2 portion, and the radical polymerizable compound (C) is cyclic. It has a high refractive index because it has high refractive index sites represented by sulfur atoms derived from other than sulfide and mercapto groups, aromatic rings, and halogen atoms other than fluorine in the molecule. That is, the concentration of the radically polymerizable compound (C) having a high refractive index is increased in the bright part of the interference pattern irradiation part, and the compound (A) represented by the general formula (I) having a low refractive index in the light dark part. Therefore, the refractive index modulation degree (Δn) is further increased.

In particular, in a reflection hologram used for image recording, as the refractive index modulation degree (Δn) increases, the diffraction efficiency (peak value of the diffraction spectrum) rapidly approaches 100%, while the full width at half maximum is almost equal to Δn. Increases linearly. That is, the refractive index modulation degree (Δn) increases as the diffraction efficiency approaches 100% and the full width at half maximum increases.

Thus, according to the present invention, even in a composition in which a radical reaction system and a cation reaction system coexist, a hologram can be recorded with a sensitivity equivalent to that of a composition consisting only of a radical reaction system, and high hologram recording characteristics. A photopolymer composition for hologram recording and a hologram recording medium can be obtained. The hologram recording medium is suitable not only for recording various data but also for image recording.

It is a top view which shows the outline of the hologram recording optical system used in the Example.

The hologram recording material of the present invention comprises a compound (A) represented by the general formula (I), a binder polymer (B), a radical polymerizable compound (C), a cationic polymerizable compound (D), a radical polymerization initiator system ( E), and the radically polymerizable compound (C) is a material containing a compound having a site selected from the group consisting of a sulfur atom derived from other than a cyclic sulfide and a mercapto group, an aromatic ring, and a halogen atom other than fluorine. It is.

（Ｉ）
ここで、Ｒ１は主鎖の炭素数が３以上のアルキル基、Ｒ２は芳香環以外の有機基、ｎは２以上である。 The hologram recording medium of the present invention has a base material and a hologram recording layer made of the hologram recording material of the present invention formed on the base material. In this specification, the hologram recording layer may be referred to as a hologram recording material layer or simply a recording material layer.

(I)
Here, R1 is an alkyl group having 3 or more carbon atoms in the main chain, R2 is an organic group other than an aromatic ring, and n is 2 or more.

The compound (A) represented by the general formula (I) forms a concentration distribution complementary to the radical polymerizable compound (C) in the recording material, and contributes to the improvement of the refractive index modulation degree Δn. In a preferred embodiment, the compound (A) represented by the general formula (I) is a compound having a refractive index lower by 0.03 or more than any average refractive index of the radical polymerizable compound (C). Is preferred. More preferably, the compound has a refractive index lower by 0.05 or more. The refractive index in this specification is defined as n20 / D (refractive index at 20 ° C. with Na D line) or a weighted average thereof.

Further, since the compound (A) represented by the general formula (I) also acts as a plasticizer during recording, it is preferably a liquid compound at room temperature (25 ° C.). Further, the compound (A) represented by the general formula (I) is decomposed by heat to produce a free carboxyl group, and this carboxyl group reacts with the cationic polymerizable compound (D) to be cured, whereby the recording layer In order to improve the glass transition temperature, the storage stability after hologram recording can be dramatically improved.

（II）
（Ｒ１は主鎖の炭素数が３以上のアルキル基である）
で示されるビニルエーテル化合物と、多価カルボン酸類とを、酸触媒の存在下で室温ないし１００℃程度で反応させることにより得ることができる。 The compound (A) represented by the general formula (I) is represented by the following general formula (II)

(II)
(R1 is an alkyl group having 3 or more carbon atoms in the main chain)
Can be obtained by reacting a polyvalent carboxylic acid with a polyvalent carboxylic acid at room temperature to about 100 ° C. in the presence of an acid catalyst.

The polyvalent carboxylic acids are preferably compounds that do not contain an aromatic ring in the molecule, and examples include alicyclic polyvalent carboxylic acids such as tetrahydrophthalic acid, fatty acids such as adipic acid, sebacic acid, succinic acid, and butanetetracarboxylic acid. Examples thereof include, but are not limited to, unsaturated polyvalent carboxylic acids such as aliphatic polycarboxylic acids, maleic acid, fumaric acid, and itaconic acid.

As the binder polymer (B), any of the compound (A) represented by the general formula (I), the radical polymerizable compound (C), the cationic polymerizable compound (D), and the radical polymerization initiator (E) Use a polymer with good compatibility. The polymer here is a concept including oligomers (polymers having a low degree of polymerization and a low molecular weight).

Examples of the binder polymer (B) include a homopolymer of a monomer having an ethylenically unsaturated double bond, a copolymer with another monomer copolymerizable with the monomer, a condensation polymer of a diol and a dicarboxylic acid. A thermoplastic resin such as a polymer, a polymer of hydroxycarboxylic acid, or a cellulose derivative can be used. Specific examples include polyvinyl acetate, polyvinyl butyrate, polyvinyl formal, polyacrylic acid, polymethacrylic acid, polyacrylic acid or polymethacrylic acid ester, cellulose acetate, cellulose triacetate, cellulose acetate butyrate, polyethylene, polypropylene, polyethylene. -Various things, such as a vinyl acetate copolymer, are mentioned. As a binder polymer, only 1 type may be used and 2 or more types may be used together.

The refractive index of the binder polymer (B) preferably has a refractive index lower by 0.03 or more than the average refractive index of the radical polymerizable compound (C) described later. Furthermore, it is more preferable that it has a refractive index as low as 0.05 or more.

As the radically polymerizable compound (C), a compound having an ethylenically unsaturated double bond in the molecule is preferable, particularly from a monofunctional or polyfunctional (meth) acrylic acid ester monomer having an aromatic ring in the molecule. It is good to choose. By introducing a site selected from the group consisting of a sulfur atom derived from other than cyclic sulfide and mercapto group, an aromatic ring, and a halogen atom other than fluorine into the molecule, the refractive index is increased. Moreover, oligomers, such as a dimer and a trimer of a (meth) acrylic acid ester monomer, may be sufficient.

Specific examples of the radical polymerizable compound (C) include benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, epichlorohydrin (ECH) modified phenol (meth) acrylate, ethylene oxide (EO). Modified cresol (meth) acrylate, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxypropylphthalic acid, tribromophenyl (meth) acrylate, o-phenylphenol (meth) acrylate, p-cumyl Phenol (meth) acrylate, bisphenol A di (meth) acrylate, bisphenol F di (meth) acrylate, tetrabromobisphenol A di (meth) acrylate, tetrabromobisphe F di (meth) acrylate, 1,4-dihydroxynaphthalene (meth) acrylate, 9,9-bis (4-hydroxyphenyl) full orange (meth) acrylate, 9,9-bis (3-methyl-4- Hydroxyphenyl) full orange (meth) acrylate, 9,9-bis (3,5-dimethyl-4-hydroxyphenyl) full orange (meth) acrylate, 9,9-bis (3-phenyl-4-hydroxyphenyl) full Examples include, but are not limited to, orange (meth) acrylate, 9,9-bis (6-hydroxynaphthyl) full orange (meth) acrylate, and EO-modified, propylene oxide (PO) -modified or ECH-modified compounds. It is not something. Of these, (meth) acrylic acid ester monomers having a 9,9-diarylfluorene skeleton are particularly preferred.

As said radically polymerizable compound (C), only 1 type of said (meth) acrylic acid ester monomer may be used, and 2 or more types may be used together. Furthermore, you may use together the (meth) acrylic acid ester monomer which does not have an aromatic ring. In the present invention, in order to make the radical polymerizable compound (C) have a high refractive index, the average refractive index of the radical polymerizable compound (C) is preferably 1.50 or more, for example, 1.55 or more. It is more preferable that

As the compound (D) capable of cationic polymerization, there are a case where a high refractive index cationic polymerizable compound (D1) is used and a case where a low refractive index cationic polymerizable compound (D2) is used, both within the scope of the present invention. Is included. Further, the high refractive index cationic polymerizable compound (D1) and the low refractive index cationic polymerizable compound (D2) may be used in combination.

When the high refractive index cationic polymerizable compound (D1) is used as the cationic polymerizable compound (D), the high refractive index cationic polymerizable compound (D1) is a refractive index lattice together with the radical polymerizable compound (C). Form. More specifically, according to the concentration distribution derived from the radical polymerizable compound (C) formed at the time of hologram recording, the high refractive index cationic polymerizable compound (D1) diffuses after recording, so that the refractive index modulation degree. Δn is amplified. The average refractive index of the high refractive index cationically polymerizable compound (D1) is, for example, preferably 1.50 or more, and more preferably 1.55 or more.

The high refractive index cationic polymerizable compound (D1) is a high refractive index site selected from the group consisting of sulfur atoms derived from other than cyclic sulfide and mercapto group, aromatic rings, and halogen atoms other than fluorine in the molecule. A monofunctional or polyfunctional epoxy group and / or oxetanyl group-containing compound may be selected. Moreover, oligomers, such as a dimer and a trimer of an epoxy group and / or oxetanyl group containing monomer, may be sufficient. Examples of the epoxy group include a 1,2-epoxyethyl group (ethylene oxide group) and a 3,4-epoxycyclohexyl group.

Specific examples of the compound having a 1,2-epoxyethyl group among the high refractive index cationically polymerizable compound (D1) include styrene oxide, phenyl glycidyl ether, benzyl glycidyl ether, o-sec-butylphenyl glycidyl ether, o-Phenylphenol glycidyl ether, 4,4′-bis (hexafluoropropylidene) bisphenol diglycidyl ether, 4,4′-cyclohexylidene bisphenol diglycidyl ether, 4,4′-oxybisphenol diglycidyl ether, tetrabromo Bisphenol A diglycidyl ether, tetrabromobisphenol F diglycidyl ether, 9,9′-bis [4- (glycidyloxy) phenyl] fluorene, 9,9-bis [3-methyl-4-glycidyl Oxy) phenyl] fluorene, 9,9-bis [3,5-dimethyl-4- (glycidyloxy) phenyl] fluorene, 9,9-bis [3-phenyl-4- (glycidyloxy) phenyl] fluorene, Examples thereof include, but are not limited to, 9-bis [6- (glycidyloxy) naphthyl] fluorene and EO-modified, PO-modified, or ECH-modified compounds thereof. Of these, a 1,2-epoxyethyl group-containing monomer having a 9,9-diarylfluorene skeleton is particularly preferable.

Specific examples of the compound having a 3,4-epoxycyclohexyl group among the high refractive index cationically polymerizable compound (D1) include 1,4-bis [(3,4-epoxycyclohexyl) methoxymethyl] benzene, 4 , 4'-bis [(3,4-epoxycyclohexyl) methoxymethyl] -1,1'-biphenyl, 2- (3,4-epoxycyclohexyl) ethyldiphenylphosphine oxide, 10- [2- (3,4- Epoxycyclohexyl) ethyl] -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, and EO-modified, PO-modified or ECH-modified compounds thereof. An aromatic skeleton-containing alicyclic epoxy compound disclosed in JP-A-2009-179568 can also be suitably used, but is not limited thereto. Among these, 3,4-epoxycyclohexyl group-containing monomers having a 9,9-diarylfluorene skeleton are particularly preferable.

Specific examples of the compound having an oxetanyl group among the high refractive index cationically polymerizable compound (D1) include 1,4-bis {[3- (ethyloxetane-3-yl) methoxy] methyl} benzene, 3- Ethyl-3-phenoxymethyloxetane, 4,4′-bis [3- (ethyloxetane-3-yl) methoxy] -1,1′-biphenyl, 2,2′-bis [3- (ethyloxetane-3- Yl) methoxy] -1,1′-biphenyl, bis [3- (ethyloxetane-3-yl) methoxy] naphthalene, bisphenol A bis [3- (ethyloxetane-3-yl) methyl] ether, bisphenol F bis [ 3- (Ethyloxetane-3-yl) methyl] ether, 4,4 ′-(hexafluoropropylidene) bisphenol bis [3- (ethyl Oxetane-3-yl) methyl] ether, tetrabromobisphenol A bis [3- (ethyloxetane-3-yl) methyl] ether, tetrabromobisphenol F bis [3- (ethyloxetane-3-yl) methyl] ether, 4,4 ′-(Hexafluoropropylidene) tetrabromobisphenol bis [3- (ethyloxetane-3-yl) methyl] ether, 4,4′-cyclohexylidenebisphenol bis [3- (ethyloxetane-3-yl) ) Methyl] ether, 4,4′-oxybisphenol bis [3- (ethyloxetane-3-yl) methyl] ether, 9,9-bis {4- [3- (ethyloxetane-3-yl) methoxy] phenyl } Fluorene, and these EO-modified, PO-modified or ECH-modified compounds, etc. But it is lower, but the invention is not limited thereto. Of these, an oxetanyl group-containing monomer having a 9,9-diarylfluorene skeleton is particularly preferable.

As said high refractive index cationically polymerizable compound (D1), only 1 type of the monomer which has said epoxy group and / or oxetanyl group may be used, and 2 or more types may be used together.

On the other hand, when the low refractive index cationic polymerizable compound (D2) is used as the cationic polymerizable compound (D), the low refractive index cationic polymerizable compound (D2) is the radical polymerizable compound (D2) in the recording material. A density distribution complementary to C) is formed, which contributes to improvement of the refractive index modulation degree Δn. In a preferred embodiment, the low refractive index cationic polymerizable compound (D2) has a refractive index lower by 0.03 or more than any average refractive index of the radical polymerizable compound (C). More preferably, it has a refractive index lower by 0.05 or more. The low refractive index cationically polymerizable compound (D2) is preferably a liquid compound at room temperature (25 ° C.) because it acts as a plasticizer during recording. Since the low refractive index cationically polymerizable compound (D2) has a cationic reactive group, the glass transition temperature of the material after hologram recording is improved by cationic polymerization after hologram recording. The storage stability of can be improved.

As the low refractive index cationically polymerizable compound (D2), specifically,
2-ethylhexyl glycidyl ether, dodecyl glycidyl ether, glycerol diglycidyl ether, diethylene glycol diglycidyl ether, 1,2-cyclohexanecarboxylic acid diglycidyl, 1,4-cyclohexanedimethanol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, poly (ethylene glycol) diglycidyl ether, poly (propylene glycol) diglycidyl ether, 1,3-bis (3-glycidoxypropyl) -1 Compounds having 1,2-epoxyethyl groups, such as 1,3,3-tetramethyldisiloxane;
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, bis (3,4-epoxycyclohexyl) adipate, bis (3,4-epoxycyclohexyl) suberate, bis (3,4-epoxycyclohexyl) sebacate Compounds having 3,4-epoxycyclohexyl groups, such as bis [2- (3,4-epoxycyclohexyl) ethyl] tetramethyldisiloxane;
3-ethyl-3-hydroxymethyloxetane, 2-ethylhexyloxetane, ethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, diethylene glycol bis (3-ethyl-3-oxetanylmethyl) ether, poly (ethylene glycol) bis Compounds having an oxetanyl group, such as (3-ethyl-3-oxetanylmethyl) ether, poly (propylene glycol) bis (3-ethyl-3-oxetanylmethyl) ether;
1,4-butanediol, 1,6-hexanediol, cyclohexane-1,4-dimethanol, poly (caprolactone) diol, poly (ethylene glycol), poly (propylene glycol), poly (tetramethylene glycol), 1, Examples thereof include compounds having a hydroxy group, such as 3-bis (3-hydroxypropyl) -1,1,3,3-tetramethyldisiloxane.

Moreover, a cation non-reactive plasticizer (F) can also be used in this invention as needed. The function of the cationic nonreactive plasticizer (F) is the same as that of the low refractive index cationically polymerizable compound (D2) except that it does not undergo cationic polymerization.

Specific examples of the cationic non-reactive plasticizer (F) include dipentyl malonate, dihexyl malonate, didodecyl succinate, bis (2-ethylhexyl) succinate, didodecyl glutarate, bis (2-ethylhexyl) adipate adipate Dibasic acid esters such as didecyl acid, didodecyl suberate, diethyl sebacate, dibutyl sebacate, bis (2-ethylhexyl) maleate, bis (2-ethylhexyl) fumarate, didodecyl citraconic acid, dododecyl mesaconic acid; poly ( Polyether glycols such as ethylene glycol), poly (propylene glycol), poly (tetramethylene glycol), and alkyl ethers thereof; dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, vinylene carbonate Carbonates such as propylene carbonate; poly (dimethylsiloxane), poly (methylphenylsiloxane), hexaethyldisiloxane, 1,3-dibutyl-1,1,3,3-tetramethyldisiloxane, 1,3-bis ( Examples include, but are not limited to, organosiloxanes such as 3-acetoxypropyl) tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, and dodecamethylcyclohexasiloxane. It is not a thing.

The radical polymerization initiator system (E) must generate radicals when irradiated with light having a wavelength used for hologram recording. When the wavelength is in the visible light range of about 400 to 700 nm, it is difficult to generate radicals with only one compound, and in general, a radical initiator (E1) and a photosensitizing dye (E2) are used in combination. . Photosensitizing dye (E2) is excited by irradiation with light of a predetermined wavelength, and electron transfer or energy transfer from photosensitizing dye (E2) to radical initiator (E1), or photosensitization from radical initiator (E1). Electron transfer or energy transfer to the dye-sensitive dye (E2) occurs, and as a result, the radical initiator (E1) generates radicals or cations. In the present invention, the combination of the radical initiator (E1) and the photosensitizing dye (E2) is referred to as the radical initiator system (E).

Examples of the radical initiator (E1) include carbonyl compounds such as benzoin ethyl ether, benzophenone, and diethoxyacetophenone;
Acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide;
Organotin compounds such as tributylbenzyltin;
Alkylaryl borates such as tetrabutylammonium butyltriphenylborate, tetrabutylammonium butyltris (tert-butylphenyl) borate, tetrabutylammonium butyltrinaphthylborate;
Diaryl iodonium salts such as diphenyliodonium hexafluorophosphate, diphenyliodonium tetrafluoroborate, diphenyliodonium hexafluoroantimonate;
iron arene complexes such as η5-cyclopentadienyl-η6-cumenyl-iron (1 +)-hexafluorophosphate (1-);
Triazine compounds such as tris (trichloromethyl) triazine;
3,3′-di (tert-butylperoxycarbonyl) -4,4′-di (methoxycarbonyl) benzophenone, 3,3 ′, 4,4′-tetrakis (tert-butylperoxycarbonyl) benzophenone, di- organic peroxides such as tert-butylperoxyisophthalate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, tert-butylperoxybenzoate;
Bisimidazole derivatives such as 2,2′-bis (o-chlorophenyl) -4,4 ′, 5,5′-tetraphenyl-1,1′-bisimidazole;
Etc.

Moreover, as a commercially available thing which can be used as said radical initiator (E1), Darocur 1173, Irgacure 184, Irgacure 907 (all are the BASF AG make), BT-2 (made by Chisso Corporation) etc., for example. It may be used.

On the other hand, examples of the photosensitizing dye (E2) include thioxanthene dyes, merocyanines, coumarins, ketocoumarins, porphyrins, cyanines, merocyanines, thiopyrylium salts, squaryliums, thiazines, acridines and the like. Is mentioned. The photosensitizing dye that is suitably used depends on the type of the radical initiator (E1) to be used and the wavelength of light used for hologram recording. The photosensitizing dye (E2) may be used alone or in combination of two or more.

The mass ratio of the radical initiator (E1) to the photosensitizing dye (E2) is generally such that the photosensitizing dye (E2) is 1 to 100 parts by weight of the radical initiator (E1). It is preferable to use it so that it may become 100 weight part.

For a preferred range of the blending weight of each component in the photopolymer composition for hologram recording of the present invention,
5 to 50 parts by weight of the compound (A) represented by the general formula (I),
5 to 50 parts by weight of the binder polymer (B),
10 to 70 parts by weight of the radical polymerizable compound (C),
10 to 70 parts by weight of the cationic polymerizable compound (D),
0.1-20 parts by weight of the radical polymerization initiator system (E),
0 to 40 parts by weight of the cationic non-reactive plasticizer (F),
Preferably,
10 to 40 parts by weight of the compound (A) represented by the general formula (I),
10 to 40 parts by weight of the binder polymer (B),
20 to 60 parts by weight of the radical polymerizable compound (C),
20 to 60 parts by weight of the cationic polymerizable compound (D),
0.3 to 10 parts by weight of the radical polymerization initiator system (E),
More preferably, the cation non-reactive plasticizer (F) is 0 to 20 parts by weight.

In addition to the above components, various additions such as a cationic polymerization initiator, a surfactant, a polymerization inhibitor, a chain transfer agent, a radical polymerization reaction and / or a promoter for promoting the cationic polymerization reaction, and an ultraviolet absorber An agent may be added.

The hologram recording material of the present invention can be produced as a uniform composition by mixing each component. The mixing method may be any of various known methods. At the time of mixing, it is preferable to add a diluting solvent for promoting the homogenization of each component and obtaining a viscosity suitable for coating. Examples of the diluent solvent include acetone, methanol, ethanol, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, n-butyl acetate, propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, toluene, xylene, anisole, dimethyl sulfoxide, and N-methyl. Various organic solvents having a boiling point of 50 ° C. or higher and 200 ° C. or lower, such as pyrrolidone, acetonitrile, tetrahydrofuran, or a mixture thereof can be used.

The obtained hologram recording material composition solution is applied onto a resin transparent substrate such as polyethylene terephthalate (PET), polycarbonate, triacetyl cellulose resin (TAC), polyimide, etc., and the dilution solvent is dried to form a film. A holographic recording material layer is obtained. In this way, a hologram recording material layer in which the above components are uniformly dispersed or dissolved is produced.

The hologram recording medium of the present invention has a base material and a hologram recording material layer formed on the base material. A three-layer structure can be formed by further coating a base material on the hologram recording material layer. The thickness of the hologram recording material layer is not particularly limited, and may be determined as appropriate from the required specifications of the recording apparatus in which the present recording medium is used, for example, about 5 to 500 μm.

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]
(Production of hologram recording medium sample)
According to the following procedure, a recording material composition solution having the composition shown in Table 1 was prepared.
As a compound (A) represented by the general formula (I), 1.0 g of cyclohexane-1,4-dicarboxylic acid bis- (1-isobutoxyethyl) ester (manufactured by Iwatani Gas Co., Ltd., BiB-CHDC-p) In addition, vinyl acetate polymer (manufactured by Sigma-Aldrich, weight average molecular weight Mw = 100,000, n20 / D = 1.47) 1.6 g as binder polymer (B), 9,9− as radical polymerizable compound (C) Bis [4- (2-acryloyloxyethoxy) phenyl] fluorene (manufactured by Shin-Nakamura Chemical Co., Ltd., NK ester A-BPEF, n20 / D = 1.62) 1.0 g, high refractive index cationically polymerizable compound (D1 ) Fluorene monomer having 1,2-epoxyethyl group and 9,9-diarylfluorene skeleton (Osaka Gas Chemical Co., Ltd. Gusol EG-250, n20 / D = 1.58) 0.6 g, low refractive index cationic polymerizable compound (D2), neopentyl glycol diglycidyl ether (manufactured by Sigma Aldrich, n20 / D = 1.46) 0 0.4 g, 0.2 g of diethyl sebacate (manufactured by Tokyo Chemical Industry Co., Ltd., n20 / D = 1.44) was added as a cationic non-reactive plasticizer (F). To this mixture, 20 mg of photosensitizing dye (E2) was further added as 3-ethyl-2- [3- (3-ethyl-1,3-benzothiazol-2 (3H) -ylidene) prop-1-ene. -1-yl] -1,3-benzothiazol-1-ium = hexafluoro-λ ⁵ -phosphanoid and tetrabutylammonium butyltrinaphthylborate which is an organoboron compound as photo radical polymerization initiator (E1) (Showa Denko 1.07 g acetone solution (1.00 g as acetone) in which 50 mg was dissolved was added and stirred to dissolve. In this way, a recording material composition solution was obtained.

The obtained recording material composition solution was applied onto a 100 μm-thick PET film using a bar coater and dried under reduced pressure at room temperature overnight. The recording material layer after drying had a thickness of about 25 μm. This was attached to a slide glass having a thickness of 1.00 mm so that the recording material layer was in close contact with the glass surface to obtain a hologram recording medium sample.

(Characteristic evaluation)
The hologram recording medium sample of Example 1 was evaluated for characteristics using a hologram recording optical system as shown in FIG. The direction of the paper surface of FIG.

In FIG. 1, the hologram recording medium sample (1) is set so that the recording material layer is perpendicular to the horizontal direction.

In the hologram recording optical system of FIG. 1, an Nd: YAG laser (wavelength of 532 nm) is used as a recording light source (11), and light oscillated from the light source (11) is converted into an electromagnetic shutter (12), a convex lens (13), Filter and collimate spatially by a pinhole (14) and a convex lens (15), and split into two light beams by a beam splitter (18) through a mirror (16) and a half-wave plate (17), Each of the divided light beams was adjusted to enter perpendicularly to the recording material layer of the hologram recording medium sample (1) via the mirrors (19, 20) and the apertures (21, 22).

Using this optical system, a reflection hologram was recorded on the hologram recording medium sample (1). The recording conditions were a light intensity of 30 mW / cm ² and an exposure time of 0.1 to ² seconds (exposure energy: 3 to 60 mJ / cm ² ). Thereafter, the entire surface of the hologram recording medium sample (1) was irradiated with 50 mW / cm ² of UV light for 60 seconds (exposure energy: 3000 mJ / cm ² ). The color derived from the photosensitizing dye (E2) was completely eliminated by irradiation with UV light (photo post cure). Further, the hologram recording medium sample (1) is heated at 180 ° C. for 5 minutes to decompose the blocked carboxylic acid (A), and the crosslinking reaction between the carboxyl group formed by decomposition and the cationic polymerizable compound (D). (Heat post cure).

The post-cure hologram recording medium sample was set in a spectrophotometer (V-660 manufactured by JASCO Corporation), and the transmission spectrum was measured. The diffraction efficiency and diffraction wavelength of the reflection hologram were determined from the peak intensity and peak wavelength at that time. Further, the full width at half maximum was determined from the transmission spectrum. The results are shown in Table 1.

The diffraction efficiency η was calculated from the diffraction wavelength obtained by a spectrophotometer, the transmittance T _p (%) at the diffraction wavelength, and the baseline transmittance T ₀ (%) by the following equation. The results of diffraction efficiency when saturation is reached are shown in Table 1.
Diffraction efficiency η (%) = [(T ₀ −T _p ) / T ₀ ] × 100

The recording sensitivity of the hologram recording medium was calculated by defining the minimum exposure energy required until the diffraction efficiency η (%) calculated as described above was saturated. The results are also shown in Table 1.

[Examples 2 to 5]
A hologram recording medium sample was prepared in the same manner as in Example 1 except that the constituent components were changed to the compounds and blending compositions shown in Table 1, and the characteristics were evaluated. The results are also shown in Table 1. Further, the refractive index (n20 / D) of each component of the binder polymer (B), the radical polymerizable compound (C), and the cationic polymerizable compound (D) is also shown in Table 1.

[Comparative Example 1]
(Production of hologram recording medium sample)
According to the following procedure, a recording material composition solution having the composition shown in Table 1 was prepared.
As the binder polymer (B), vinyl acetate polymer (manufactured by Sigma-Aldrich, weight average molecular weight Mw = 100,000, n20 / D = 1.47) 1.6 g and 9,9-bis as the radical polymerizable compound (C) [4- (2-acryloyloxyethoxy) phenyl] fluorene (NK ester A-BPEF, n20 / D = 1.62, manufactured by Shin-Nakamura Chemical Co., Ltd.) 1.0 g, high refractive index cationically polymerizable compound (D1) As a fluorene monomer having a 1,2-epoxyethyl group and a 9,9-diarylfluorene skeleton (Ogsol EG-250, n20 / D = 1.58, manufactured by Osaka Gas Chemical Co., Ltd.) 1.0 g, low As a refractive index cationic polymerizable compound (D2), neopentyl glycol diglycidyl ether (manufactured by Sigma-Aldrich, n2 0 / D = 1.46) 0.8 g and 0.4 g of diethyl sebacate (manufactured by Tokyo Chemical Industry Co., Ltd., n20 / D = 1.44) as a cationic non-reactive plasticizer (F) were added. To this mixture, 20 mg of photosensitizing dye (E2) was further added as 3-ethyl-2- [3- (3-ethyl-1,3-benzothiazol-2 (3H) -ylidene) prop-1-ene. -1-yl] -1,3-benzothiazol-1-ium = hexafluoro-λ ⁵ -phosphanoid and tetrabutylammonium butyltriphenylborate which is an organoboron compound as photo radical polymerization initiator (E1) (Showa Denko 50 mg) and 1.12 g acetone solution (1. As acetone) in which 50 mg triarylsulfonium hexafluoroantimonate (Sun Shine SI-100L, Sanshin Chemical Industry Co., Ltd.) was dissolved as a cationic polymerization initiator. 00 g) was added and stirred to dissolve. In this way, a recording material composition solution was obtained.

The obtained recording material composition solution was applied onto a 100 μm-thick PET film using a bar coater and dried under reduced pressure at room temperature overnight. The recording material layer after drying had a thickness of about 25 μm. This was attached to a 1.0 mm-thick slide glass so that the recording material layer was in close contact with the glass surface to obtain a hologram recording medium sample.

Thereafter, the characteristics were evaluated in the same manner as in Example 1. The results are also shown in Table 1. Further, the refractive index (n20 / D) of each component of the binder polymer (B), the radical polymerizable compound (C), and the cationic polymerizable compound (D) is also shown in Table 1.

[Comparative Examples 2-3]
A hologram recording medium sample was prepared in the same manner as in Example 1 except that the constituent components were changed to the compounds and blending compositions shown in Table 1, and the characteristics were evaluated. The results are also shown in Table 1. Further, the refractive index (n20 / D) of each component of the binder polymer (B), the radical polymerizable compound (C), and the cationic polymerizable compound (D) is also shown in Table 1.

[Description of ingredients used]
Compound (A) represented by general formula (I)
BiB-CHDC-p: cyclohexane-1,4-dicarboxylic acid bis- (1-isobutoxyethyl) ester (manufactured by Iwatani Gas Co., Ltd.) (compound of the following formula (III))

（III）
・ＡＢ−１：アジピン酸ビス−（１−イソブトキシエチル）エステル（下記式（IV）の化合物）

(III)
AB-1: Adipic acid bis- (1-isobutoxyethyl) ester (compound of formula (IV) below)

（IV）
・ＡＢ−２：アジピン酸ビス−（２−エチルヘキシル）エステル（下記式（V）の化合物）

(IV)
AB-2: Adipic acid bis- (2-ethylhexyl) ester (compound of the following formula (V))

（V）
・ＢｉＰ−ＣＨＤＣ−ｐ：シクロヘキサン−１，４−ジカルボン酸ビス−（１−イソプロポキシエチル）エステル（岩谷瓦斯（株）製）（下記式（VI）の化合物）

(V)
BiP-CHDC-p: cyclohexane-1,4-dicarboxylic acid bis- (1-isopropoxyethyl) ester (manufactured by Iwatani Gas Co., Ltd.) (compound of the following formula (VI))

（VI）
・ＴＥＨ：１，２，４−トリメリット酸トリプロポキシエステル（下記式（VII）の化合物）

(VI)
TEH: 1,2,4-trimellitic acid tripropoxy ester (compound of formula (VII) below)

（VII）

(VII)

Binder polymer (B)
Vinyl acetate polymer (Sigma Aldrich, Mw = 100,000)

Radical polymerizable compound (C)
A-BPEF: 9,9-bis [4- (2-acryloyloxyethoxy) phenyl] fluorene (manufactured by Shin-Nakamura Chemical Co., Ltd.)
R-551: EO-modified bisphenol A diacrylate (manufactured by Nippon Kayaku Co., Ltd.)

Cationic polymerizable compound (D)
High refractive index cationically polymerizable compound (D1)
EG-250 :: Fluorene monomer having 1,2-epoxyethyl group and 9,9-diarylfluorene skeleton (manufactured by Osaka Gas Chemical Co., Ltd.)
Low refractive index cationically polymerizable compound (D2)
・ Neopentyl glycol diglycidyl ether (manufactured by Sigma-Aldrich)

Radical polymerization initiator system (E)
Radical polymerization initiator (E1)
・ N3B: Tetrabutylammonium butyltrinaphthyl borate (manufactured by Showa Denko KK)
Photosensitizing dye (E2)
Dye-1: 3-ethyl-2- [3- (3-ethyl-1,3-benzothiazol-2 (3H) -ylidene) prop-1-en-1-yl] -1,3-benzothiazole -1-ium = hexafluoro-λ ⁵ -phosphanoid (compound of the following formula (VIII))

（VIII）

(VIII)

Cationic non-reactive plasticizer (F)
・ Diethyl sebacate (Tokyo Chemical Industry Co., Ltd.)

Cationic polymerization initiator, SI-100L: Triarylsulfonium hexafluoroantimonate (manufactured by Sanshin Chemical Industry Co., Ltd.)

In the hologram recording medium samples of Examples 1 to 3, BiB-CHDC-p (R1 has 3 main chain carbon atoms and R2 is a cyclohexyl group) as the compound (A) represented by the general formula (I) Was used, high recording characteristics (diffraction efficiency of 98% or more) and high recording sensitivity (4 to 5 mJ / cm ² ) were achieved during reflection hologram recording. Furthermore, it is more preferable to use A-BPEF having a 9,9-diarylfluorene skeleton as the radical polymerizable compound and EG-250 having an aromatic ring in the molecule as the cationic polymerizable compound (D) because the full width at half maximum is increased.

In Examples 4 and 5, AB-1 (the main chain of R1 has 3 carbon atoms and R2 is an alkyl group) and AB-2 (as R1) are represented as the compound (A) represented by the general formula (I). By using a main chain having 6 carbon atoms and R2 is composed of an alkyl group, high diffraction efficiency (98% or more) and high recording sensitivity (4 to 5 mJ) can be obtained in the same manner as in Example 1 during reflective hologram recording. / Cm ² ).

In Comparative Example 1, a photocationic polymerization initiator (SI-100L) is used instead of the compound (A) represented by the general formula (I). In this case, diffraction efficiency equivalent to that of Examples 1 to 3 using the compound (A) represented by the general formula (I) was obtained, but the hologram recording sensitivity was lowered (about 9 mJ / cm ² ). It can be judged that the recording sensitivity is lowered because a part of the irradiation energy at the time of hologram recording is absorbed by the cation initiator. From this result, the superiority of the present invention can be said.

In Comparative Example 2, BiP-CHDC-p (R1 has 2 main chain carbon atoms and R2 is a cyclohexyl group) is used as the compound (A) represented by the general formula (I). In this case, high hologram recording sensitivity was obtained, but diffraction efficiency was low. This is presumably because the alkyl substituent R ₁ has a short chain length and thus cannot exhibit sufficient hydrophobicity, and as a result, the function as a plasticizer was insufficient.

In Comparative Example 3, TEH (R1 has 3 main chain carbon atoms and R2 is an aromatic ring) is used as the compound (A) represented by the general formula (I). In this case, high hologram recording sensitivity was obtained, but diffraction efficiency was low. This is because the refractive index of the compound (A) is high because R2 is an aromatic ring, and the refractive index pattern at the time of hologram recording becomes unclear. From this result, R2 is an organic group other than the aromatic ring. There is a need.

(1): Hologram recording medium sample (11): Light source (12): Shutter (13), (15): Convex lens (14): Pinhole (16), (19), (20): Mirror (17): Half-wave plate (18): Beam splitter (21), (22): Aperture

Claims (4)

Including the compound (A) represented by the following general formula (I), binder polymer (B), radical polymerizable compound (C), cationic polymerizable compound (D), radical polymerization initiator system (E), radical polymerization The photopolymer composition for hologram recording, wherein the functional compound (C) has a site selected from the group consisting of a sulfur atom derived from other than a cyclic sulfide and a mercapto group, an aromatic ring, and a halogen atom other than fluorine.

(I)
Here, R1 is an alkyl group having 3 or more carbon atoms in the main chain, R2 is an organic group other than an aromatic ring, and n is 2 or more. The photopolymer composition for hologram recording according to claim 1, wherein at least a part of the radical polymerizable compound (C) has a 9,9-diarylfluorene skeleton. At least a part of the cationically polymerizable compound (D) is a compound having a site selected from the group consisting of a sulfur atom derived from other than cyclic sulfide and mercapto group, an aromatic ring, and a halogen atom other than fluorine, The photopolymer composition for hologram recording according to claim 1. A hologram recording medium comprising: a base material; and a hologram recording layer comprising the photopolymer composition for hologram recording according to claim 1, which is formed on the base material.

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