JP4177867B2 - Photosensitive composition for recording volume hologram, recording medium using the same, and method for forming volume hologram - Google Patents

Description

  The present invention relates to a volume hologram recording photosensitive composition, a recording medium using the same, and a volume hologram recording method. More particularly, the present invention relates to a photosensitive composition for volume hologram recording that provides a hologram with excellent refractive index modulation and heat resistance, and a volume hologram recording method that can easily produce a hologram using the same.

  A hologram is made by interfering two light beams with the same wavelength (object light and reference light) and recording the wave front of the object light as an interference fringe on a photosensitive material. When light with the same conditions as the original reference light is applied to this hologram A diffraction phenomenon due to interference fringes occurs, and the same wavefront as the original object light can be reproduced.

  Holograms are classified into several types according to the recording pattern of interference fringes, but in recent years, so-called volume holograms that record interference fringes with a difference in the refractive index inside the recording layer have become highly effective due to their high diffraction efficiency and excellent wavelength selectivity. It is being applied to applications such as three-dimensional displays and optical elements.

  As a material for recording such a volume hologram, a material using silver halide or dichromated gelatin conventionally used in the art field is generally used. However, since these require wet development and complicated development and fixing processing, they are unsuitable for industrial production of holograms, and have the problem that images disappear due to moisture absorption after recording. .

  In order to solve these problems, US Pat. Nos. 3,658,526 and 3,993,485 propose that volume holograms can be produced using a photopolymer only by a simple dry process. Has been. In addition, as to the presumed formation mechanism of the hologram by the photopolymer, “Applied Optics” (BL Booth, Vol. 14, No. 3, PP593-601 (1975) and J. Tomlinson, EA Chandros, etc., Vol. 15, No. 2, PP 534-541 (1976), etc. However, these are described. As for the technology, refractive index modulation, which is the most important performance of a hologram, does not reach the above-mentioned conventional technology.

In recent years, as a photopolymer material excellent in refractive index modulation, a photopolymer material using a radical polymerizable compound and a cationic polymerizable compound having different refractive indexes described in JP-A No. 5-107999 has been proposed. When this material is used, a volume hologram with a relatively large refractive index modulation can be obtained by dry processing. However, in an environment where heat is applied, such as 50 ° C. to 100 ° C., the diffraction efficiency decreases and the reproduction wavelength changes over time. There was a problem. Accordingly, there is a demand for the appearance of a volume hologram that solves these problems and retains the initial performance even in a hot environment.
U.S. Pat. No. 3,658,526 US Pat. No. 3,993,485 JP-A-5-107999 “Applied Optics” (BL Booth, Vol. 14, No. 3, PP593-601 (1975) W. J. et al. Tomlinson, E.M. A. Chandros et al., Volume 15, No. 2, PP 534-541 (1976)

  An object of the present invention is to provide a photosensitive composition having a high refractive index modulation and giving a volume hologram excellent in heat resistance, and a method for producing a volume hologram using the same.

That is, the present invention relates to a photosensitive composition for volume hologram recording used for recording interference fringes generated by interference of laser light or light having excellent coherence as fringes having different refractive indexes. ,
(A) a cationically polymerizable compound that is liquid at room temperature,
(B) a radically polymerizable compound,
(C) Each component of a radical photopolymerization initiator system that polymerizes the component (b) by being exposed to the above laser beam or light having excellent coherence, and (d) a cationic polymerization initiator system having thermal potential. A photosensitive composition for recording volume holograms is provided.

  The present invention also provides a recording medium and a volume hologram recording method using the composition. Furthermore, this invention provides the hologram obtained using the said composition.

  The cationic polymerizable compound (a) used in the present invention is obtained by polymerizing the radical polymerizable compound (b) described later by irradiation with laser light or light with excellent coherence (hereinafter referred to as first exposure), Bronsted acid generated from the cationic polymerization initiator system (d) or photocationic polymerization initiator system (e) having thermal potential in the composition by the subsequent heat treatment or overall exposure (hereinafter referred to as post-exposure). Alternatively, it is cationically polymerized with a Lewis acid. As the cationically polymerizable compound (a), a liquid compound at room temperature is used so that the polymerization of the radically polymerizable compound (b) is carried out in a composition having a relatively low viscosity throughout. As such a cationically polymerizable compound (a), for example, “Chemtech. Oct.” (JV Crivello, page 624, (1980)], Examples thereof include compounds described in JP-A 62-149784, Journal of the Adhesion Society of Japan [Vol. 26, No. 5, pp. 179-187 (1990)].

  Specific examples of the cationically polymerizable compound (a) include diglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, 1,4-bis (2,3-epoxypropoxyperfluoroisopropyl) cyclohexane, sorbitol polyglycidyl ether, trimethylol. Propane polyglycidyl ether, resorcin diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, phenyl glycidyl ether, para t-butylphenyl glycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl Ester, dibromophenyl glycidyl ether, dibromoneopentyl glycol diglycidyl ether, 1,2,7,8-diepoxyoct 1,6-dimethylol perfluorohexane diglycidyl ether, 4,4′-bis (2,3-epoxypropoxyperfluoroisopropyl) diphenyl ether, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexane Carboxylate, 3,4-epoxycyclohexyloxirane, 1,2,5,6-diepoxy-4,7-methanoperhydroindene, 2- (3,4-epoxycyclohexyl) -3 ′, 4′-epoxy-1 , 3-Dioxane-5-spirocyclohexane, 1,2-ethylenedioxy-bis (3,4-epoxycyclohexylmethane), 4 ', 5'-epoxy-2'-methylcyclohexylmethyl-4,5-epoxy- 2-methylcyclohexanecarboxylate, ethylene glycol-bis (3,4 -Epoxycyclohexanecarboxylate), bis- (3,4-epoxycyclohexylmethyl) adipate, di-2,3-epoxycyclopentyl ether, vinyl-2-chloroethyl ether, vinyl-n-butyl ether, triethylene glycol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, trimethylolethane trivinyl ether, vinyl glycidyl ether, and formula

で表わされる化合物が挙げられ、これらの１種以上を使用してよい。

And one or more of these may be used.

  The radically polymerizable compound (b) used in the present invention preferably has at least one ethylenically unsaturated double bond in the molecule. The average refractive index of the radical polymerizable compound (b) is preferably larger than that of the cationic polymerizable compound (a). When the average refractive index of the compound (b) is lower than that of the compound (a), the refractive index modulation becomes insufficient, which is not preferable.

Specific examples of the radical polymerizable compound (b) include acrylamide, methacrylamide, styrene, 2-bromostyrene, phenyl acrylate, 2-phenoxyethyl acrylate, 2,3-naphthalenedicarboxylic acid (acryloxyethyl) monoester, Methylphenoxyethyl acrylate, nonylphenoxyethyl acrylate, β-acryloxyethyl hydrogen phthalate, phenoxy polyethylene glycol acrylate, 2,4,6-tribromophenyl acrylate, diphenic acid (2-methacryloxyethyl) monoester, benzyl acrylate, 2 , 3-Dibromopropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-naphthyl acrylate, N-vinylcarbazole, 2- (9 Carbazolyl) ethyl acrylate, triphenylmethyl thioacrylate, 2- (tricyclo [5,2,10 ^2.6] dibromo decyl thio) ethyl acrylate, S- (1-naphthylmethyl) thio-acrylate, dicyclopentanyl acrylate, methylenebis Acrylamide, polyethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, diphenic acid (2-acryloxyethyl) (3-acryloxypropyl-2-hydroxy) diester, 2,3-naphthalene dicarboxylic acid (2- Acryloxyethyl) (3-acryloxypropyl-2-hydroxy) diester, 4,5-phenanthrene dicarboxylic acid (2-acryloxyethyl) (3-acryloxypropyl-2-hydroxy) Loxy) diester, dibromoneopentylglycol diacrylate, dipentaerythritol hexaacrylate, 1,3-bis [2-acryloxy-3- (2,4,6-tribromophenoxy) propoxy] benzene, diethylenedithioglycol diacrylate 2,2-bis (4-acryloxyethoxyphenyl) propane, bis (4-acryloxydiethoxyphenyl) methane, bis (4-acryloxyethoxy-3,5-dipromophenyl) methane, 2,2- Bis (4-acryloxyethoxyphenyl) propane, 2,2-bis (4-acryloxydiethoxyphenyl) propane, 2,2-bis (4-acryloxyethoxy-3,5-dibromophenyl) propane, bis ( 4-acryloxyethoxyphenyl) sulfone, bis ( -Acryloxydiethoxyphenyl) sulfone, bis (4-acryloxypropoxyphenyl) sulfone, bis (4-acryloxyethoxy-3,5-dibromophenyl) sulfone, and compounds in which the above acrylate is replaced with methacrylate, Examples thereof include compounds containing at least two S atoms in the molecule, as described in JP-A-2-247205 and JP-A-2-261808, and those having 1 More than seeds may be used.

  The radically polymerizable compound (b) of the present invention also has a 9,9-diarylfluorene skeleton, is liquid at normal temperature, and has at least one ethylenically unsaturated double bond in the molecule. Also good. When this is used, high refractive index modulation is easily obtained. A radically polymerizable compound having a 9,9-diarylfluorene skeleton and being liquid at room temperature has the formula

R ₁ , R ₂ : At least one terminal has a radical polymerizable group such as acryloyl group or methacryloyl group, and this group and the benzene ring are at least one oxyethylene chain, oxypropylene chain, urethane bond, It is bonded through an amide bond.

Specific examples of X _{1 to} X ₄ : represented by H, alkyl group (C _{1 to} C ₄ ), alkoxy group (C _{1 to} C ₄ ), amino group, dialkylamino group, hydroxyl group, carboxyl group, halogen group and the like .

Among these, those in which an acryloyl group or a methacryloyl group is bonded to a benzene ring via an oxyethylene chain or an oxypropylene chain are particularly preferred in R ₁ and R ₂ . Specific examples thereof include 9,9-bis (4-acryloxydiethoxyphenyl) fluorene, 9,9-bis (4-acryloxytriethoxyphenyl) fluorene, and 9,9-bis (4-acryloxytetra). Ethoxyphenyl) fluorene, 9,9-bis (4-acryloxydipropoxyphenyl) fluorene, 9,9-bis (4-acryloxyethoxy-3-methylphenyl) fluorene, 9,9-bis (4-acryloxy) Ethoxy-3-ethylphenyl) fluorene, 9,9-bis (4-acryloxydiethoxy-3-ethylphenyl) fluorene, 9,9-bis (4-acryloxyethoxy-3,5-dimethyl) fluorene and the above There are compounds in which “acryloxy” is replaced with “methacryloxy”.

  The radical photopolymerization initiator system (c) used in the present invention generates an active radical by the first exposure for producing a hologram, and the active radical is one of the constituents of the present invention. Any initiator system that polymerizes the compound (b) may be used. Examples of such a radical photopolymerization initiator system (c) include, for example, U.S. Pat. Nos. 4,766,055, 4,868,092, 4,965,171, and JP-A-54-151024. Gazette, 58-15,503 gazette, 58-29,803 gazette, 59-189,340 gazette, 60-76735 gazette, Japanese Patent Laid-Open No. 1-28715, Japanese Patent Application No. 3- No. 5569 and “Proceedings of Conference on Radiation Curing Asia” (P.461-477, 1988), etc. Agent systems can be used, but not limited to this.

  In the present specification, “initiator system” means that a sensitizer, which is a component that generally absorbs light, and an active radical generating compound or an acid generating compound can be used in combination. A sensitizer in the radical photopolymerization initiator system often uses a colored compound such as a dye to absorb visible laser light, but the final hologram requires colorless transparency (for example, an automobile) As a sensitizer for use in a head-up display such as those described above, cyanine series as described in JP-A-58-29803, JP-A-1-287105, and Japanese Patent Application No. 3-5569 The use of dyes is preferred.

  Since cyanine dyes are generally easily decomposed by light, the dyes in the hologram are decomposed and absorbed in the visible range by being left exposed for several hours to several days under post-exposure or indoor light or sunlight in the present invention. A colorless and transparent hologram is obtained. Specific examples of the cyanine dye include anhydro-3,3′-dicarboxymethyl-9-ethyl-2,2′thiacarbocyanine betaine, anhydro-3-carboxymethyl-3 ′, 9-diethyl-2,2 'Thiacarbocyanine betaine, 3,3', 9-triethyl-2,2'-thiacarboxyanine iodine salt, 3,9-diethyl-3'-carboxymethyl-2,2'-thiacarbocyanine iodine salt 3,3 ′, 9-triethyl-2,2 ′-(4,5,4 ′, 5′-dibenzo) thiacarbocyanine iodine salt, 2- [3- (3-ethyl-2-benzothiazoli) Den) -1-propenyl] -6- [2- (3-ethyl-2-benzothiazolidene) ethylideneimino] -3-ethyl-1,3,5-thiadiazolium iodine salt, 2-[[ 3-allyl-4-oxo-5- (3- -Propyl-5,6-dimethyl-2-benzothiazolidylene) -ethylidene-2-thiazolinylidene] methyl] 3-ethyl-4,5-diphenylthiazolinium iodine salt, 1,1 ', 3,3 3 ', 3'-hexamethyl-2,2'-indotricarbocyanine iodine salt, 3,3'-diethyl-2,2'-thiatricarbocyanine perchlorate, anhydro-1-ethyl-4 -Methoxy-3'-carboxymethyl-5'-chloro-2,2'-quinothiocyanine betaine, anhydro-5,5'-diphenyl-9-ethyl-3,3'-disulfopropyloxacarbocyanine hydroxide Triethylamine salt, 2- [3- (3-ethyl-2-benzothiazolidene) -1-propenyl] -6- [2- (3-ethyl-2-benzothiazolidene) ethylideneimino] -3 -Ethyl-1,3,5-thiadiazolium / iodine salt may be mentioned, and one or more of these may be used.

  Examples of active radical generating compounds that may be used in combination with cyanine dyes are those described in JP-A-58-29803, JP-A-1-287105, and Japanese Patent Application No. 3-5569. Examples include diaryliodonium salts and 2,4,6-substituted-1,3,5-triazines. The use of diaryliodonium salts is particularly preferred when high photosensitivity is required. Specific examples of the diaryl iodonium salts include diphenyl iodonium, 4,4′-dichlorodiphenyl iodonium, 4,4′-dimethoxydiphenyl iodonium, 4,4′-ditertiary butyl diphenyl iodonium, 3,3′-dinitrodiphenyl iodonium. Such as chloride, bromide, tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate, hexafluoroantimonate and the like. Specific examples of 2,4,6-substituted-1,3,5-triazines include 2-methyl-4,6-bis (trichloromethyl) -1,3,5-triazine, 2,4,6 -Tris (trichloromethyl) -1,3,5-triazine, 2-phenyl-4,6-bis (trichloromethyl) -1,3,5-triazine, 2,4-bis (trichloromethyl) -6- ( Examples include p-methoxyphenylvinyl) -1,3,5-triazine, 2- (4′-methoxy-1′-naphthyl) -4,6-bis (trichloromethyl) -1,3,5-triazine and the like. The

  The cationic polymerization initiator system (d) having thermal potential used in the present invention is capable of initiating polymerization of a cationic polymerizable compound by generating an initiation species such as Bronsted acid or Lewis acid by the action of heat. Although not particularly limited, it is preferable to use a cationic polymerization initiator system having the following thermal potential:

General formula,

[Wherein, each R ^c represents the same or different —COR ^a , —R ^b , a hydroxy group, a cyano group or an amino group which may be substituted with an alkyl group, and each R ^d may be the same or different. Represents ^a different H, —R ^a or halogen atom, and A represents

を表わし、

Represents

Each R ^e may be the same or different, and may have the same or different alkyl group having 1 to 12 carbon atoms (which may form an aromatic ring with each other) or alkenyl group (these are hydroxy, carboxy, nitro, cyano, 4 may be substituted by alkoxy or alkanoyloxy group.) or a phenyl group (which is a halogen atom, nitro, cyano, amino, -NR ^c, optionally substituted with -R ^a or -OR ^a group R ^a represents an alkyl or cycloalkyl group having 1 to 4 carbon atoms which may be substituted with a hydroxy group, and R ^b represents H, —R ^a , —OR ^a , a halogen atom or a nitro group, X is table of _{AsF 6, SbF 6, BF 4} , PF 6, ClO 4, FeCl 4, CF 3 SO 3, R e SO 3 or ^R e COO . ]
A compound represented by:

General formula,

Wherein each ^{R f} is selected from the same or different H, -R ^a, an alkenyl group or an -R ⁱ 2 to 3 carbon atoms, each ^{R g} is selected from the same or different -R ^a Represents an alkenyl group having 2 to 3 carbon atoms or —R ⁱ , and each R ^h represents H, hydroxy group, —R ^a , —OR ^a or —R ^i, which may be the same or different, and R ⁱ represents phenyl Represents ^a group (which may be substituted with ^a halogen atom, hydroxy, nitro, cyano, —NHR ^a , —R ^a or —OR ^a group), m represents an integer of 1 to 4 and R ^a And X are as defined above. ]
And a compound represented by:

General formula,

[Wherein R ^j is the same or different alkyl group having 1 to 20 carbon atoms (which may be mutually formed as a ring) or an alkenyl group (these are hydroxy, carboxy, nitro, cyano, carbon number 1 to 4 alkoxy or optionally substituted with an alkanoyloxy group) or a phenyl group (this is an amino group optionally substituted with a halogen atom, nitro, cyano or alkyl group, R ^a or OR ^a Represents an optionally substituted group)]
The compound represented by these is mentioned.

  In the present specification, “thermal potential” refers to a property that develops a function only after heating at a certain temperature or higher.

  Among these, a benzylammonium salt compound represented by the general formula [I] is particularly preferable for obtaining a hologram excellent in refractive index modulation, heat resistance and light resistance.

Specific examples include N-benzyl-N, N-dimethylanilinium, N- (p-methoxybenzyl) -N, N-dimethylanilinium, N- (p-methylbenzyl) -N, N- as the cation moiety. Dimethylanilinium, N- (pt-butylbenzyl) -N, N-dimethylanilinium, N- (p-chlorobenzyl) -N, N-dimethylanilinium, N- (p-nitrobenzyl) -N , N-dimethylanilinium, N-benzyl-N, N-dimethyl-N- (p-tolyl) ammonium, 1-benzyl-2-chloropyridinium, 1- (p-methoxybenzyl) -2-chloropyridinium, 1 -(P-phenylbenzyl) -2-methylpyridinium, 1- (p-methoxybenzyl) -2-cyanopyridinium and the like, and these anions The _{^{SbF 6 -, PF 6 -,}} BF 4 -, CF 3 SO 3 -, CH 3 SO 3 -, HSO 3 - , and the like.

  Furthermore, in consideration of the stability during storage of the composition, it is preferable to use a cationic polymerization initiator system having a thermal potential that does not react at less than 70 ° C.

  In the present invention, in addition to the above cationic polymerization initiator system (d) having thermal potential, a photocationic polymerization initiation system (e) can also be used. The cationic photopolymerization initiator system (e) used in the present invention has low photosensitivity for the first exposure, and is exposed to light having a wavelength different from that of the first exposure to be exposed to Bronsted acid or In the present invention, radical polymerization may be carried out by irradiation with laser light or light having excellent coherence, as long as it is an initiator system that generates a Lewis acid and polymerizes the cationic polymerizable compound (a). During polymerization of the ionic compound, it is preferable that the cation polymerizable compound in the liquid state at room temperature is present with little reaction, and it is considered that a higher refractive index modulation than in the prior art can be obtained. Therefore, as the cationic photopolymerization initiator system, those that do not polymerize the cationically polymerizable compound during the first exposure are particularly preferable.

  Examples of the photocationic polymerization initiator system (e) include “UV curing; science and technology (UV CURING: SCIENCE AND TECHNOLOGY)” (pp. 23-76, edited by S. PETER PAPPAS),・ Technology marketing publication (A TECHNOLOGY MARKETING PUBLICATION) and “Comments Inorg. RIEDICER and A. ROLOFF), Vol. 7, No. 3, pp 109-138 (1988)], etc., and one or more of these may be used.

  Particularly preferred photocationic polymerization initiator systems (e) used in the present invention include diaryliodonium salts, triarylsulfonium salts, iron allene complexes and the like.

  Preferred examples of the diaryliodonium salts as the photocationic polymerization initiator system (e) include tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate and hexafluoroantimony of iodonium shown in the photoradical polymerization initiator (c). Nate, trifluoromethanesulfonate, 9,10-dimethoxyanthracenesulfonate, and the like. Preferred triarylsulfonium salts include triphenylsulfonium, 4-tertiarybutyltriphenylsulfonium, tris (4-methylphenyl) sulfonium, tris (4-methoxyphenyl) sulfonium, 4-thiophenyltriphenylsulfonium, and the like. Examples include sulfonium tetrafluoroborate, hexafluorophosphate, hexafluoroarsenate and hexafluoroantimonate, trifluorosulfonate, and 9,10-dimethoxyanthracene-2-sulfonate.

  In the photosensitive composition of the present invention, a polymer binder, a thermal polymerization inhibitor, a silane coupling agent, a colorant, an ultraviolet absorber and the like may be used in combination as necessary. The polymer binder is used to improve the film formability and film thickness uniformity of the composition before hologram formation, or to post-expose interference fringes formed by polymerization by irradiation with laser light or light with excellent coherence. It is used to make it exist stably until. The polymer binder only needs to be compatible with the cationic polymerizable compound or the radical polymerizable composition. Specific examples thereof include chlorinated polyethylene, polymethyl methacrylate, methyl methacrylate and other (meth) acrylic acids. Examples include alkyl ester copolymers, vinyl chloride and acrylonitrile copolymers, polyvinyl acetate, polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, ethyl cellulose, and acetyl cellulose. The polymer binder may have reactivity such as a cationic polymerizable group in its side chain or main chain.

  When a UV absorber is used in a conventional system using a cationic photopolymerization initiator, polymerization inhibition occurs. However, in a thermal latent initiator system such as the present invention, such polymerization inhibition is caused. Therefore, the combined use of an ultraviolet absorber could be realized. As the ultraviolet absorber, known ones usually used for improving weather resistance can be used, and specifically, benzotriazole, benzophenone, oxalic acid anilide, dicyanoacrylate, triazine, benzoate, etc. Although a ultraviolet absorber can be mentioned, it is not this limitation. Specific examples include 2- (5-methyl-2-hydroxyphenyl) benzotriazole, 2- (3,5-t-butyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5- Bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2- [5- (2-octyloxycarbonylethyl) -3-tert-butyl-2-hydroxyphenyl] benzotriazole, 2-hydroxy-4 -N-dodecyloxybenzophenone, 2-hydroxy-4-methacryloxyethyloxybenzophenone, 2-ethoxy-2'-dodecyloxyoxalic acid bisanilide, 2-ethoxy-5-t-butyl-2'-ethyl Oxalic acid bisanilide, ethyl-2-cyano-3,3-diphenyl acrylate, etc. I can get lost. Of these, benzotriazole-based ultraviolet absorbers are particularly preferred from the standpoint of light resistance and compatibility.

  A light stabilizer may be used in combination with the ultraviolet absorber. The light stabilizer is generally called a radical scavenger or HALS (Hindered Amine Light Stabilizers), and it is known that a synergistic effect can be obtained by using it together with an ultraviolet absorber. it can.

  In the composition of the photosensitive composition of the present invention, the component (a) is 5 to 80 wt% (especially 30 to 60 wt%) and the component (b) is 10 to 80 wt% (particularly 30 to 30 wt%) with respect to the total weight of the composition. 60 wt%), radical photopolymerization initiator system (c) is 0.3-8 wt% (especially 1-5 wt%), and cationic polymerization initiator system (d) having thermal potential is 0.3-8 wt% (especially 1 to 5 wt%) is preferable.

  The photosensitive composition of the present invention may be prepared by a usual method. For example, the above-mentioned essential components (a) to (d) and optional components can be used as they are or as necessary in solvents (for example, ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, acetone, cyclohexanone, ethyl acetate, butyl acetate, ethylene glycol diacetate) Ester solvents such as toluene, aromatic solvents such as toluene and xylene, cellosolve solvents such as methyl cellosolve, ethyl cellosolve and butyl cellosolve, alcoholic solvents such as methanol, ethanol, propanol and n-butanol, ethers such as tetrahydrofuran and dioxane System solvents, halogen solvents such as dichloromethane, dichloroethane, and chloroform), and mixing in a dark place using, for example, a high-speed stirrer.

In the production of the hologram of the present invention, the recording layer is coated on a transparent support such as a glass plate, a polyethylene terephthalate film, a polyethylene film, an acrylic plate, a triacetyl cellulose film, or a polycarbonate plate by the usual method. And it can form by drying as needed. The amount applied is selected appropriately, for example, dry coating amount may be ^{1g / m 2 ~50g / m 2} . Further, usually, a polyethylene terephthalate film, a polyethylene film, a polypropylene film, a triacetyl cellulose film, a polycarbonate plate, a glass plate, an acrylic plate or the like is provided on the recording layer as a protective layer. Thus, as another method for producing a three-layer body in which the intermediate layer is a recording layer made of the composition of the present invention, for example, recording is performed between two polyethylene terephthalate films that have been subjected to a treatment that is easy to peel off. A layer may be formed, and one film may be peeled off at the time of use, and the surface thereof may be laminated on a suitable support. For example, the composition of the present invention can be injected between two glass plates.

  Interference fringes are recorded in the recording layer produced in this way by interference fringe exposure by a normal holographic exposure apparatus with laser light and excellent coherence (for example, wavelength 300 to 1200 nm). At this stage, unreacted polymerizable compound remains in the photosensitive layer. Therefore, in order to obtain optical performance that does not change with time, it is necessary to cure the unreacted polymerizable compound. For this purpose, it is necessary to heat to a temperature higher than the temperature at which the cationic polymerization initiator system having thermal potential starts reaction following the above-described interference fringe exposure. By this operation, the unreacted cationic polymerizable compound can be polymerized to fix the interference fringes. Although polymerization of a radical polymerizable compound occurs in the above-described interference fringe exposure stage, an unreacted radical polymerizable compound may be present in the photosensitive layer in addition to the unreacted cationic polymerizable compound. Therefore, in order to increase the polymerization rate of these unreacted polymerizable compounds, it is desirable that the entire exposure of ultraviolet rays and / or visible light and the heat treatment be performed simultaneously or sequentially following the interference fringe exposure. When a high-pressure mercury lamp, a metal halide lamp or a halogen lamp is used as a light source during the entire exposure, heat rays are also emitted together with ultraviolet rays and / or visible light. Therefore, it is economical that exposure and heat treatment can be carried out simultaneously by exposing the entire surface with these light sources under conditions where the photosensitive layer is heated to a temperature higher than the reaction temperature of the cationic polymerization initiator system having thermal potential. Further, by adding the photocationic polymerization initiator system (e) to the photosensitive layer, it is possible to induce polymerization of the cationically polymerizable compound during the entire surface exposure, so that the polymerization rate of the unreacted compound in the photosensitive layer is further increased. Can be raised.

  The volume hologram includes, for example, lenses, diffraction gratings, interference filters, head-up display devices, general three-dimensional displays, optical fiber couplers, facsimile optical polarizers, memory materials such as ID cards, architectural window glass, Can be used for advertising media.

  Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. A test plate was prepared by the following method using the photosensitive composition shown in each Example and Comparative Example described later, and exposed to obtain each hologram. The physical properties were evaluated by the following method.

(Test plate creation)
After dissolving or dispersing a predetermined amount of radical photopolymerization initiator system component and cationic polymerization initiator system component in a mixture of 1.2 g of n-butyl alcohol, 1.0 g of methyl isobutyl ketone, and 0.2 g of toluene, A predetermined amount of a cationically polymerizable compound, a radically polymerizable compound and a binder polymer were added, stirred, and filtered to obtain a photosensitive solution. This photosensitive solution was applied onto a 16 cm × 16 cm glass plate using an applicator and dried at 90 degrees for 5 minutes. Further, a 80 μm thick polyethylene film (Tonen Chemical Corp. LUPIC LI) was laminated thereon using a laminating roller, and this plate was divided into 3 to 4 cm squares to obtain test plates.

(exposure)
The first exposure was performed using 514.5 nm light from an argon laser. A schematic diagram of a reflection hologram recording method is shown in FIG. The light intensity of one light beam on the test plate surface was 1 mW / cm ² and the exposure was performed for 30 seconds.
Post-heating or post-exposure conditions after the end of the first exposure will be shown in examples described later.

(Evaluation)
The diffraction efficiency of the reflection hologram was obtained from the reflectance of the hologram by Shimadzu's own spectrophotometer UV-2100 and the attached integrating sphere device ISR-260. Moreover, the film thickness of the diffraction efficiency measurement part was measured using the film thickness measuring device betascope 850 by a Fischer company. The refractive index modulation (a value that is half the change in the refractive index of the interference fringes) was calculated from the diffraction efficiency and film thickness obtained in this way. The formula is "Coupled Wave Theory for Thick Hologram Gratings" (Coupled Wave Theory for Thick Hologram Gratings) (H. Kogelnik, Bell Sist Tech J. (Bell S.) (Tech. J.) 48, 2909-2947 (1969)). The value of the refractive index modulation does not depend on the film thickness, and the refractive index modulation ability of the composition can be compared by this value.

  For the heat resistance test, the change in the diffraction efficiency and the change in the diffraction peak wavelength after the hologram test plate was left in a 100 ° C. furan device for 1000 hours were examined.

  With regard to light resistance, a hologram obtained by continuously irradiating a hologram test plate with ultraviolet light having a wavelength of 295 nm to 450 nm for 60 hours using a super accelerated weathering tester I Super UV Tester W type manufactured by Dainippon Plastic Co., Ltd. The change of the diffraction efficiency, the change of the diffraction peak wavelength, and the color difference of the test plate were examined.

  The color difference was measured by a transmission measurement method based on JIS-K7103 using a color computer SM4-CH type of Suga Test Instruments Co., Ltd.

  Photosensitive compositions of the following examples and comparative examples were prepared, holograms were prepared by the method described above, and evaluation was performed as described above.

(Examples 1-3)
Here, examples in which reflection holograms are created using various thermal latent cationic polymerization initiator systems (d) are shown. However, all the first exposures were performed at 514.5 nm for 30 seconds, then the light of a 15 W low-pressure mercury lamp was exposed for 1 minute from the polyethylene film side, and further heated at 120 ° C. for 5 minutes to produce a hologram. The test plate was hardly heated by exposure to a low-pressure mercury lamp. Incidentally, CAT-1 as a cationically polymerizable compound (a), the radical polymerizable compound is (b) A-BPHE, photo-radical polymerization initiator system as (c) is of DYE-1 and DPI · _{CF 3} SO 3 A combination was used.

  Table 1 shows the compositions and blending amounts of the photosensitive compositions for hologram recording used in Examples 1 to 3.

  Table 2 shows the results of the hologram evaluation and the heat resistance test.

  In any of the examples, a reflection hologram with high diffraction efficiency and high refractive index modulation was obtained. Further, the diffraction peak wavelength of the hologram hardly changed after the heat resistance test.

(Comparative Example 1)
This is a comparative example with respect to Examples 1 to 3, and is the same as Examples 1 to 3 except that TPS · SbF ₆ which is a photocationic polymerization initiator is used instead of the heat latent cationic polymerizable initiator system. A hologram was created.

  Table 3 shows the composition and blending amount of the photosensitive composition for hologram recording used.

  Table 4 shows the results of the hologram evaluation and the heat resistance test. After the heat resistance test, the diffraction peak wavelength of the hologram was greatly shifted by a short wavelength.

(Examples 4 to 6)
Here, the composition shown in Table 1 was used, the first exposure was performed at 514.5 nm for 30 seconds, then heated at 120 ° C. for 5 minutes, and further exposed from the polyethylene film side for 1 minute using a low-pressure mercury lamp to produce a hologram. The created example is shown. (The compositions of Examples 4, 5, and 6 are the same as Examples 1, 2, and 3 in Table 1, respectively)

  Table 5 shows the results of the hologram evaluation and the heat resistance test.

  In any of the examples, a reflection hologram having high diffraction efficiency and high refractive index modulation was obtained. In addition, the diffraction peak wavelength of the hologram almost changed after the heat resistance test.

(Comparative Example 2)
This is a comparative example with respect to Examples 4 to 6, and is the same as Examples 4 to 6 except that TPS · SbF ₆ which is a photocationic polymerization initiator is used in place of the heat latent cationic polymerization initiator system. A hologram was created. (Composition is the same as Comparative Example 1 in Table 4)

  The obtained hologram had a low diffraction efficiency of 55%, and the reproduction wavelength peak was split into a plurality.

(Examples 7 to 9)
Here, the composition shown in Table 1 was used, the first exposure was performed at 514.5 nm for 30 seconds, and then a high-pressure mercury lamp (manufactured by Nippon Battery Co., Ltd., experimental ultraviolet irradiation device, FL-1001-2) was used. An example is shown in which a hologram is formed by exposure from the polyethylene film side for 1 minute. The test plate was heated to 115 ° C. by irradiation with light from a high pressure mercury lamp. (The compositions of Examples 7, 8, and 9 are the same as Examples 1, 2, and 3 in Table 1, respectively)

  Table 6 shows the results of the hologram evaluation and the heat resistance test.

  In any of the examples, a reflection hologram having high diffraction efficiency and high refractive index modulation was obtained. Further, the diffraction peak wavelength of the hologram hardly changed after the heat resistance test.

(Comparative Example 3)
This is a comparative example with respect to Examples 7 to 9, and is the same as Examples 7 to 9 except that TPS · SbF ₆ which is a photocationic polymerization initiator is used in place of the heat latent cationic polymerizable initiator system. A hologram was created. (Composition is the same as Comparative Example 1 in Table 4)

  Table 7 shows the results of the hologram evaluation and the heat resistance test. After the heat resistance test, the diffraction peak wavelength of the hologram was greatly shifted by a short wavelength.

(Examples 10 to 12)
Here, the composition of Table 1 was used, the first exposure was performed at 514.5 nm for 30 seconds, and then exposure was performed for 1 minute from the polyethylene film side using a high-pressure mercury lamp (same as that used in Examples 7 to 9). Further, an example in which a hologram is created by heating at 120 ° C. for 5 minutes is shown. The test plate was heated to 115 ° C. by irradiation with light from a high pressure mercury lamp. (The compositions of Examples 10, 11, and 12 are the same as Examples 1, 2, and 3 in Table 1, respectively)

  Table 8 shows the results of the hologram evaluation and the heat resistance test.

  In any of the examples, a reflection hologram having high diffraction efficiency and high refractive index modulation was obtained. Further, the diffraction peak wavelength of the hologram hardly changed after the heat resistance test.

(Comparative Example 4)
This is a comparative example with respect to Examples 10 to 12, and all the same as Examples 10 to 12 except that TPS · SbF ₆ which is a photocationic polymerization initiator is used instead of the thermal latent cationic polymerization initiator system. A hologram was created. (Composition is the same as Comparative Example 1 in Table 4)

  Table 9 shows the results of the hologram evaluation and the heat resistance test. After the heat resistance test, the diffraction peak wavelength of the hologram was greatly shifted by a short wavelength.

(Example 13)
Here, an example is shown in which a hologram is prepared in the same process as in Examples 10 to 12, using a composition obtained by adding 80 mg of TPS · SbF ₆ which is a photocationic polymerization initiator to the composition of Example 1.

  Table 10 shows the results of the hologram evaluation and the heat resistance test. A reflection hologram with high diffraction efficiency and high refractive index modulation was obtained. Further, the diffraction peak wavelength of the hologram hardly changed after the heat resistance test.

(Example 14)
Here, an example is shown in which the composition of Example 1 was used, the first exposure was performed at 514.5 nm for 30 seconds, and then heated at 120 ° C. for 5 minutes to produce a hologram.

  Table 11 shows the results of the hologram evaluation and the heat resistance test. A reflection hologram with high diffraction efficiency and high refractive index modulation was obtained. Further, the diffraction peak wavelength of the hologram hardly changed after the heat resistance test.

(Comparative Example 5)
This is a comparative example with respect to Example 14, and a hologram is prepared in the same manner as Example 14 except that the photocationic polymerization initiator TPS · SbF ₆ is used instead of the thermal latent cationic polymerizable initiator system. did. (Composition is the same as Comparative Example 1 in Table 4)

  The obtained hologram had a diffraction efficiency as low as 50%, and the peak of the reproduction wavelength was split into a plurality. The heat resistance test could not be carried out because the photosensitive layer was not sufficiently cured and the polyethylene film could not be peeled off.

(Examples 15 to 17, Comparative Example 6)
Here, the photosensitive composition which added the ultraviolet absorber was used, the hologram was created in the same process as Examples 10-12, and the example which performed the performance evaluation and the light resistance test is shown. For comparison, a composition (Comparative Example 6) using only a photocationic polymerization initiator (TPS · SbF ₆ ) without using a cationic polymerization initiator system having thermal potential was also carried out.

  Table 12 shows the compositions of the photosensitive compositions for hologram recording of Examples 15 to 17 and Comparative Example 6, the evaluation results of the hologram, and the results of the light resistance test. The color difference (ΔELab) in Table 12 indicates that the smaller the numerical value, the smaller the color change.

  In any of the examples, a hologram with high diffraction efficiency and excellent light resistance was obtained. In Comparative Example 6 in which a photocationic polymerization initiator was used without using a thermal latent cationic polymerization initiator, an ultraviolet absorber was used. The action of the cationic photopolymerization initiator is hindered, resulting in the splitting of the diffraction peak into two. Further, the diffraction efficiency of the hologram after the light resistance test is reduced and the short wavelength shift of the diffraction wavelength is large, and the recording layer changes. It was observed.

  In addition, the abbreviation of the compound described in the said Examples 1-17, Comparative Examples 1-6, and Table 1-Table 12 is as follows.

Thermal latent cationic polymerization initiator system · BA-1 ··· N- (p-methoxybenzyl) -N, N-dimethylanilinium hexafluoroantimonate · BA-2 ··· 1- (p-methoxybenzyl) 2-chloropyridinium hexafluoroantimonate BA-3... N- (p-methoxybenzyl) -N, N-dimethylanilinium trifluoromethylsulfonate

Radical polymerizable compound A-BPHE ... 9,9-bis (3-ethyl-4-acryloxydiethoxyphenyl) fluorene

Cationic polymerizable compound CAT-1 ... glycidyl ether in which 4 mol of propylene oxide is added to pentaerythritol (the number of glycidyl groups per molecule is 3)

Photoradical polymerization initiator · DYE-1 ··· 3,9-diethyl-3'-carboxymethyl-2,2'-thiacarbocyanine, iodine salt · DPI · CF ₃ SO ₃ · · · diphenyliodonium · trifluoromethane Sulfonate

Photocationic polymerization initiator system, TPS, SbF ₆ ... manufactured by Ciba Geigy, triarylsulfonium hexafluoroantimonate compound, trade name UV16974

Ultraviolet absorber UVA-1... 2- [5- (2-octyloxycarbonylethyl) -3-tert-butyl-2-hydroxyphenyl] benzotriazole (manufactured by Ciba Geigy, TINUVIN 384)
・ UVA-2 ... benzotriazole-based ultraviolet absorber (manufactured by Ciba Geigy, TINUVIN 1130)

Other components P-1 ... Methyl methacrylate Ethyl acrylate Glycidyl methacrylate copolymer (Feed ratio = 11/79/10)
・ MIBK ・ ・ ・ Methyl isobutyl ketone ・ BuOH ・ ・ ・ n-butyl alcohol ・ TL ・ ・ ・ Toluene

The schematic diagram of the recording method of the reflection type hologram in the 1st exposure is shown.

Explanation of symbols

1: Glass plate 2: Recording layer 3: Polyethylene film 4: Laser 5: Laser beam 6: Mirror 7: Beam splitter 8: Objective lens 9: Lens

Claims (9)

In a photosensitive composition for volume hologram recording used for recording interference fringes caused by interference of laser light or light having excellent coherence as fringes having different refractive indexes, the composition comprises:
(a) a cationically polymerizable compound that is liquid at room temperature,
(b) a radically polymerizable compound,
(c) a radical photopolymerization initiator system that polymerizes the component (b) in response to the above laser light or light having excellent coherence, and
(d) those containing each component of a cationic polymerization initiator system that is a benzylammonium salt compound that does not initiate polymerization at a temperature lower than 70 ° C., and develops cationic polymerization initiating ability upon heating at the same temperature or higher, or the above (a ) To (d) in addition to the polymer binder (provided that the composition is
(A) an epoxy compound having an aromatic or heterocyclic ring in the molecule which may have a substituent; (B) a polymerizable ethylenically unsaturated group having essentially no aromatic ring or heterocyclic ring in the molecule; Tetrahydrofurfuryl (meth) acrylate, glycidyl (meth) acrylate or morpholinoethyl (meth) acrylate of a compound having one or more , or a compound having a polymerizable ethylenically unsaturated group having a heterocyclic ring ,
(C) a polymer binder or a cellulose-based polymer having no aromatic ring and heterocyclic ring in the molecule ,
(D) a thermal polymerization initiator system that activates polymerization of said epoxy compound, and
(E) initiation of generation of radicals and / or louisic acid by the interaction of at least one sensitizer having absorption in the wavelength range from ultraviolet to near infrared and a sensitizer exposed to actinic radiation Except for the case of containing a photopolymerization initiating system which is a mixed system with at least one kind of agent or a compound in which the sensitizer and the initiator are integrated by ionic bond or covalent bond . And a photosensitive composition for volume hologram recording.   The composition of claim 1 wherein the average refractive index of component (a) is lower than that of component (b).   The composition according to claim 1, wherein the radical polymerizable compound (b) has a 9,9-diarylfluorene skeleton and is liquid at room temperature.   It has low photosensitivity to the above laser light or light with excellent coherence, and further contains a photocationic polymerization initiator system (e) that polymerizes the component (a) in response to light of another wavelength. The composition of claim 1.   The composition according to claim 1, further comprising an ultraviolet absorber.   A volume hologram recording medium comprising a recording layer comprising the composition of claim 1 between two identical or different transparent supports.   7. A volume hologram recording method, wherein the recording medium of claim 6 is exposed to interference fringes caused by interference of laser light or light having excellent coherence, and then the recording medium is heated.   The recording medium of claim 6 is exposed to interference fringes caused by the interference of laser light or light having excellent coherence, and then the whole surface exposure and heat treatment of ultraviolet and / or visible light to the recording medium are performed simultaneously or Volume hologram recording method performed sequentially.   The recording method according to claim 8, wherein the heat treatment is performed using heat generated in an entire surface exposure process of ultraviolet and / or visible light.

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