JP2005221793A - Photopolymer composition for hologram recording material, hologram recording medium, and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photopolymer composition for a hologram recording material, a hologram recording medium, and a manufacturing method therefor, and to solve problems relating to the composition for a hologram recording material containing a cation polymerization initiator as an acid generating agent, the problems about hazard on a human body or metal corrosion of the cation (acid) remaining in the produced hologram recording medium after a hologram is formed. <P>SOLUTION: The photopolymer composition for a hologram recording material contains as essential components, a cation polymerizable compound (A), a cation polymerization initiator (B), and a specified acid receptor (C). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a photopolymer composition for volume phase type hologram recording material used for recording the intensity distribution of light and dark in an interference pattern of light as a change in refractive index, a hologram recording medium obtained therefrom, and a method for producing the same It is about.

  Volume holograms record the interference pattern of laser coherent light on a photosensitive material, etc. by refractive index modulation. Among holograms classified into several types, their high diffraction efficiency and excellent wavelength selectivity Therefore, it is used in a wide variety of fields such as optical elements, stereoscopic image displays, interference measurement, and image / information processing. As typical volume hologram recording material compositions, photosensitive materials such as silver halide emulsions and dichromated gelatin have been generally used (Non-Patent Document 1 and Non-Patent Document 2).

  However, these photosensitive materials have drawbacks such as requiring complicated processing such as wet development at the time of producing the hologram and poor weather resistance of the produced hologram. In order to overcome such problems, photosensitive materials capable of producing volume holograms only by dry processing using a photopolymer have been proposed (Patent Documents 1 and 2). These are those in which a refractive index modulation is caused by photopolymerization of a photopolymerizable monomer in a portion having a large amount of light in an interference pattern, and a volume hologram is recorded. However, these materials did not reach the above-described conventional technique in an important hologram characteristic called refractive index modulation.

  On the other hand, photopolymer materials containing radically polymerizable compounds and cationically polymerizable compounds have been proposed in order to realize hologram recording materials that do not involve complicated processing, have excellent weather resistance, and can perform recording with high diffraction efficiency. (Patent Document 3 and Patent Document 4). These were produced by performing only one polymerization (for example, radical polymerization) at the time of interference fringe recording and separately performing the other polymerization (for example, cationic polymerization) at the time of fixing, thereby obtaining a larger refractive index modulation. The hologram also has sufficient weather resistance.

  In addition, from another viewpoint, a photopolymer material using only cationic polymerization without using radical polymerization has been proposed (Patent Document 5). This overcomes disadvantages caused by radical polymerization, such as polymerization inhibition due to oxygen and image distortion due to curing shrinkage, by using only cationic polymerization.

  However, in the photopolymer compositions using these cationic polymerization curing systems, cations (acids) generated from the acid generator contained in the material remain in the coating film, so that they are affixed to other substrates (for example, metals). There was a problem in terms of safety, such as corrosiveness when combined and there is a risk of causing inflammation when contacted with the skin (Non-patent Document 3).

U.S. Pat. No. 3,993,485 US Pat. No. 3,658,526 Publication No. 2873126 JP-A-5-181271 Japanese National Patent Publication No. 11-512847 Display Holography Handbook, pp. 66-67, Thumbprint Library (1985) Optical Engineering Handbook, 351-353, Asakura Shoten (1986) Journal of the Adhesion Society of Japan, Vol.34 No.10 (1998)

  The object of the present invention relates to a composition for a hologram recording material containing a cationic polymerization initiator that is an acid generator, such as the danger of cation (acid) remaining in the produced hologram recording medium to the human body or metal corrosivity. Is a solution.

  The above object is achieved by the present invention described below. That is, the present invention is a photopolymer composition for a holographic recording material, which contains a cationic polymerization initiator, a cationic polymerizable compound, and a specific acid acceptor as essential components.

  The specific acid acceptor (C) contained in the recording material composition of the present invention is generated from the cationic polymerization initiator (B) remaining in the hologram recording layer after a series of hologram recording / fixing operations. In order to effectively capture the acid, the basic problems of the hologram photosensitive material and the durability of the completed hologram are not reduced, and the problems of metal corrosion and danger to the human body, which have been problematic, are improved. We were able to.

Next, the present invention will be described in more detail with reference to preferred embodiments.
The cationically polymerizable compound (A) used in the present invention may contain at least one cyclic ether group and thioether group represented by an oxirane ring and an oxetane ring. Vinyl ethers, spiro orthoesters, spiro ortho carbonates, and bicyclo ortho esters can also be used.

Specific examples of such a cationically polymerizable compound (A) include, for example, phenyl glycidyl ether, 2-ethylhexyl glycol glycidyl ether, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, and polyethylene glycol diglycidyl ethers. Glycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, glycerin diglycidyl ether, trimethylolpropane triglycidyl ether 2,2-dibromoneopentyl glycol diglycidyl ether . Examples of oxetane compounds include 3-ethyl-3-hydroxymethyloxetane, 1,4-bis {[(3-ethyl-3-oxetanyl) methoxy] methyl} benzene, 3-ethyl-3- (phenoxymethyloxetane), di [1-ethyl (3-oxetanyl)] methyl ether, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, 3-ethyl-3-{[3- (triethoxysilyl) propoxy] methyl} oxetane, Examples include oxetanylsilsesquioxysan and phenol novolac oxetane.
Particularly preferred as the cationically polymerizable compound (A) are divinyl ether monomer, 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, and di [1-ethyl (3-oxetanyl)] methyl ether.

  The cationic polymerization initiator (B) used in the present invention may be any compound that generates a Bronsted acid or a Lewis acid upon exposure and polymerizes the cationic polymerizable compound (A). In addition, when the hologram recording material composition contains a radical polymerizable compound (E) and a radical polymerizable initiator (F) described later, the radical polymerizable compound is polymerized in the bright part of the interference fringe exposure, and the hologram latent image Is formed, the cationic polymerization initiator (B) may be a compound that generates an acid upon heating to polymerize the cationically polymerizable compound.

Examples of the cationic polymerization initiator (B) that generates such an acid include diazonium salts, iodonium salts, sulfonium salts, selenonium salts, silanol / aluminum complexes, sulfonic acid esters, imide sulfonates, iron arene complexes, and pyrylium salts. , Acid anhydrides, amines, hydrazides, dicyandiamides and the like. The cationic polymerization initiator (B) may be an onium salt that generates radicals and cations simultaneously when activated, for example, an iodonium salt or a sulfonium salt.
Particularly preferred as the cationic polymerization initiator (B) are diphenyliodonium salts and triphenylsulfonium salts.

  The amount of the cationic polymerization initiator (B) used is preferably 0.1 to 30 parts by weight, more preferably 0.5 to 15 parts by weight, based on 100 parts by weight of the cationic polymerizable compound (A).

  The acid acceptor (C) contained in the photopolymer composition for a hologram recording material of the present invention is an acid remaining after recording or fixing without interfering with cationic polymerization by an acid generated during hologram recording or fixing ( Cation) is adsorbed or neutralized. In addition, such an acid-accepting agent (C) is preferably one that is sufficiently compatible with other compositions so as not to cause a decrease in transparency and recording properties of the recording medium to be produced.

The acid acceptor (C) used in the present invention is an oxide, a hydroxide, a carboxylate, a silicate, a carbonate, a phosphite, a Group I oxide and a hydroxide of the periodic table as a metal compound. Examples thereof include borates, alkoxides, Group IVA metal oxides, basic phosphites, basic carbonates, basic carboxylates, basic sulfites, and tribasic sulfates. A layered compound such as a zeolite compound or hydrotalcite can also be used. Specific examples are magnesia, magnesium hydroxide, barium hydroxide, magnesium carbonate, barium carbonate, slaked lime, quicklime, calcium carbonate, calcium silicate, calcium stearate, zinc stearate, calcium phthalate, magnesium phosphite, calcium phosphite. , Zinc white, tin oxide, risurge, red lead, lead white, dibasic lead phthalate, dibasic lead carbonate, tin stearate, basic lead phosphite, basic tin phosphite, basic lead sulfite, three Basic lead sulfate, natural zeolite, A-type, X-type, Y-type synthetic zeolite, sodalite, natural or synthetic mordenite, and the like. Moreover, amine organic compounds in which the reaction of unpaired electrons on nitrogen, such as hindered amines and proton sponges, are suppressed sterically.
Metal alkoxide, hydrotalcite and hindered amine can be preferably used, and most preferred is a polymer of diethoxycalcium, dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol. It is.

  The amount of the acid acceptor (C) used is preferably 5 to 250 parts by weight, more preferably about 10 to 150 parts by weight with respect to 100 parts by weight of the cationic polymerization initiator (B).

  If necessary, the photopolymer composition for hologram recording material of the present invention may further contain a binder (D).

The binder (D) optionally used in the present invention may be any one that has good compatibility with the cationically polymerizable compound (A) and the radically polymerizable compound (E) used as necessary to be described later. A homopolymer or copolymer obtained by polymerizing a monomer having an ethylenically unsaturated double bond, a condensation polymer of a diphenol compound and a dicarboxylic acid compound, a polymer having a carbonate group in the molecule, and- Examples thereof include a polymer having a SO ₂ — group and a cellulose derivative.

Specific examples of the binder (D) include polyvinyl acetate, polyvinyl butyrate, polyvinyl formal, polyvinyl carbazole, polyacrylic acid, polymethacrylic acid, polymer acrylate, polymethyl methacrylate, polyethyl acrylate, polybutyl acrylate, polymethacrylate. Ronitrile, polyethyl methacrylate, polybutyl methacrylate, polyacrylonitrile, poly-1,2-dichloroethylene, ethylene-vinyl acetate copolymer, syndiotactic polymethyl methacrylate, poly-α-vinyl naphthalate, polycarbonate, cellulose acetate , Cellulose triacetate, cellulose acetate butyrate, polystyrene, poly-α-methylstyrene, poly-o-methylstyrene, poly-p-methylstyrene Poly-p-phenylstyrene, poly-2,5-dichlorostyrene, poly-p-chlorostyrene, poly-2,5-dichlorostyrene, polyarylate, polysulfone, polyethersulfone, styrene-acrylonitrile copolymer Polymer, styrene-divinylbenzene copolymer, styrene-butadiene copolymer, styrene-maleic anhydride copolymer, ABS resin, polyethylene, polyvinyl chloride, polypropylene, polyethylene terephthalate, polyvinyl pyrrolidone, polyvinylidene chloride, hydrogenated styrene -Butadiene-styrene copolymer, transparent polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, a copolymer of (meth) acrylic acid cyclic aliphatic ester and methyl (meth) acrylate, and the like. The above examples of the binder (D) may be used alone or in combination of two or more.
Particularly preferred as the binder (D) are methyl methacrylate polymer and vinyl acetate polymer.

  The preferable addition amount of the binder (D) is desirably in the range of 1 to 1000 parts by weight, more preferably 10 to 300 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound (A).

  In principle, the photopolymer composition for hologram recording material of the present invention adopts a cationic polymerization curing system as described above, but uses a radical polymerization curing system in combination without departing from the gist of the present invention. It's okay. In this case, the radical polymerizable compound (E) and the radical polymerization initiator (F) are further added as additional components.

  The radically polymerizable compound (E) optionally used in the present invention may be any one having good compatibility with the cationically polymerizable compound (A) and the binder (D) used as necessary. It may be selected from the group consisting of so-called acrylate monomers having saturated double bonds, methacrylic monomers, vinyl monomers, and combinations of two or more thereof.

Specific examples of the (meth) acrylate monomer include methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, isodecyl methacrylate, n-lauryl methacrylate, n-stearyl methacrylate, methoxydiethylene glycol methacrylate, cyclohexyl meta Crate, tetrahydrofurfuryl methacrylate, benzyl methacrylate, phenoxyethyl methacrylate, isobornyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl methacrylate, dimethyl Aminoethyl methacrylate , Diethylaminoethyl methacrylate, glycidyl methacrylate, tert-butyl methacrylate, isostearyl methacrylate, n-butoxyethyl methacrylate, isoamyl acrylate, lauryl acrylate, stearyl acrylate, butoxyethyl acrylate, ethoxyethylene glycol acrylate, methoxytriethylene glycol acrylate, phenoxyethyl acrylate , Tetrahydrofurfuryl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl succinic acid, 2-acryloyloxyethyl phthalic acid , Isooctyl acrylate, isomyristyl Relate, isostearyl acrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, nonaethylene glycol diacrylate, 1,4-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate 1,9-nonanediol dimethacrylate, glycerin dimethacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, neopentyl glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,10-decanediol dimethacrylate, Ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate , Tetraethylene glycol diacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, glycerin diacrylate, 2-hydroxy-3-acryloyloxypropyl Acrylate, neopentyl glycol diacrylate, 1,3-butanediol diacrylate, 1,10-decanediol diacrylate, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol Tetramethacrylate, pentaerythritol tetraacrylate, ditrimethylolpropane tetramethacrylate, ditrimethylol B bread tetraacrylate, tetramethylolmethane tetraacrylate, dipentaerythritol hexamethacrylate, dipentaerythritol hexaacrylate, and the like.
Further, it may be a dimer or trimer oligomer of the above compound, and may be used alone or in combination of two or more.

Specific examples of the vinyl monomer include vinyl acetate, 4-vinylaniline, 9-vinylanthracene, 4-vinylanisole, vinylbenzaldehyde, vinylbenzoate, vinylbenzyl chloride, 4-vinylbiphenyl, vinyl bromide, N-vinylcaprolactam, Vinyl chloroformate, vinyl crotonate, vinyl cyclohexane, 4-vinyl-1-cyclohexene diepoxide, vinyl cyclopentane, vinyl decanoate, 4-vinyl-1,3-dioxolan-2-one, vinyl carbonate, vinyl Trithiocarbonate, vinyl 2-ethylhexanoate, vinyl ferrocene, vinylidene chloride, vinyl formate, 1-vinyl imidazole, 2-vinyl naphthalene, vinyl neodecanoate, 5-vinyl Lu-2-norbornene, 4- (vinyloxy) butylbenzoate, 2- (vinyloxy) ethanol, 4-vinylphenyl acetate, vinyl pivalate, vinyl propionate, 2-vinylpyridine, 1-vinyl-2-pyrrolidinone, vinylsulfone, vinyl Examples include trimethylsilane. Further, it may be a dimer or trimer oligomer of the above compound, and may be used alone or in combination of two or more.
Particularly preferred as the radical polymerizable compound (E) are phenoxyethyl acrylate, pentaerythritol triacrylate, and neopentyl glycol diacrylate.

  The radical polymerizable compound (E) is preferably in the range of 10 to 300 parts by weight, more preferably 30 to 100 parts by weight with respect to 100 parts by weight of the cationic polymerizable compound (A).

  Examples of the radical polymerization initiator (F) that is optionally used in combination with the radical polymerizable compound (E) in the present invention include a carbonyl compound, an organic tin compound, an alkylaryl boron salt, an onium salt, an iron arene complex, Halogenomethyl-substituted triazine compounds, organic peroxides, bisimidazole derivatives, titanocene compounds and the like are used.

Examples of the compound include benzyl, benzoin ethyl ether, benzophenone, diethoxyacetophenone, tributylbenzyltin, tetrabutylammonium / triphenylbutylborate, triphenyl-n-butylborate, diphenyliodonium salt, η5-cyclopentadienyl-η6 -Cumenyl-iron (1 +)-hexafluorophosphate (1-), tris (trichloromethyl) triazine, 3,3 ', 4,4'-tetra (tert-butylperoxycarbonyl) benzophenone, di-tert-butyl Peroxyisophthalate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, tert-butylperoxybenzoate, 2,2'-bis (o-chlorophenyl) -4,4 ', 5 , 5'-Tetraphenyl-1,1'-bi Midazole, bis (2,4,5-triphenyl) imidazolyl, bis (η5-2,4-cyclopentadien-1-yl) -bis (2,6-difluoro-3- (1H-pyrrol-1-yl) -Phenyl) titanium can be exemplified. These may be used alone or in combination of two or more.
Particularly preferred as the radical polymerization initiator (F) is 3,3 ′, 4,4′-tetra- (t-butylperoxycarbonyl) benzophenone.

  The radical polymerization initiator (F) is preferably in the range of 5 to 50 parts by weight, more preferably 10 to 30 parts by weight with respect to 100 parts by weight of the radical polymerizable compound (E).

  In the present invention, a photosensitizing dye (G) may be used in combination as appropriate. The photosensitizing dye (G) is a laser used for hologram recording: laser light such as He—Ne (wavelength 633 nm), Ar (wavelength 515,488 nm), YAG (wavelength 532 nm), He—Cd (wavelength 442 nm). It may absorb, and may exhibit a spectral sensitizing action on either one or both of the cationic polymerization initiator (B) and the radical polymerization initiator (F) optionally used. What works on one side is more suitable. Examples of such a photosensitizing dye include mihiraketone, acridine yellow, merocyanine, methylene blue, camphorquinone, eosin, decarboxylated rose bengal, and the like.

  The photosensitizing dye (G) may be any substance that absorbs light in the visible region. In addition to the above, for example, cyanine derivatives, merocyanine derivatives, phthalocyanine derivatives, xanthene derivatives, thioxanthene derivatives, acridine derivatives, porphyrins Derivatives, coumarin derivatives, ketocoumarin derivatives, quinolone derivatives, stilbene derivatives, oxazine derivatives, thiazine dyes and the like can be used. Photosensitizing dyes described in “Chemicals” (Shin Okawara et al., CMC, 1983) and “Special functional materials” (Tadasaburo Ikemori et al., CMC, 1986) can also be used. These may be used alone or in combination of two or more.

  The photosensitizing dye (G) comprises a cationically polymerizable compound (A), a cationic polymerization initiator (B), an acid acceptor (C), and a binder (D) contained as necessary, a radically polymerizable compound ( E) is preferably in the range of 0.01 to 1 part by weight, more preferably 0.03 to 0.5 part by weight, based on 100 parts by weight of the total of the radical polymerization initiator (F).

  The hologram recording material composition according to the present invention may further contain additives such as a plasticizer, a thickener, a thermal polymerization inhibitor, a chain transfer agent, a solvent, and the like, if necessary.

  The plasticizer is a non-reactive compound with respect to the cationically polymerizable compound (A), the binder (D), and the radically polymerizable compound (E) that can be optionally used. Examples of the plasticizer include phthalic acid esters represented by dimethyl phthalate, diethyl phthalate and dioctyl phthalate; dimethyl adipate, dibutyl adipate, dimethyl sebacate, diethyl sebacate, dibutyl sebacate and diethyl succinate Basic acid esters; orthophosphates typified by trimethyl phosphate, triethyl phosphate, triphenyl phosphate, tricresyl phosphate; acetates typified by glyceryl triacetate and 2-ethylhexyl acetate; triphenyl phosphite, dibutyl Inactive compounds such as phosphites represented by hydrogen phosphite are exemplified. The plasticizer may be used alone or in combination of two or more.

  As thickeners, inorganic fine particles such as silica gel “Daiso Gel SP Series”, Fuji Silysia Chemical “Silysia” and “Fuji Silica Gel”, Shionogi Pharmaceutical “Carplex”, Japan “Aerosil” manufactured by Aerosil Co., “Leolo Seal”, “Toc Seal”, “Fine Seal” manufactured by Tokuyama Co., Ltd., etc. can be used. Or organic fine particles, for example, diallyl phthalate polymers that can be prepared by the methods described in JP-A-10-72510 and JP-A-10-310684, or “New Material Series“ Cutting-edge Technology of Ultrafine Particles Polymer ”” (CMC, "PB, 200 series" manufactured by Kao Corporation, supervised by Soichi Muroi, 1991), "Bellpearl series" manufactured by Kanebo Co., Ltd., "Techpolymer series" manufactured by Sekisui Plastics Co., Ltd., "Micropearl series" manufactured by Sekisui Fine Chemical Co., Ltd. "MR series" "MP series" manufactured by Soken Chemical Co., Ltd. can be used. The particle size of these fine particles is only required to be smaller than the film thickness of the hologram and is usually preferably in the range of 0.1 to 20 μm.

  The organic solvent is effective for improving the film-forming property in addition to adjusting the viscosity and compatibility, for example, acetone, xylene, toluene, methyl ethyl ketone, tetrahydrofuran, benzene, methylene chloride, dichloromethane, chloroform, methanol, etc. Is often used. However, water cannot be used because it inhibits viscosity adjustment, compatibility adjustment, film-forming property, and the like. Water cannot be used as a medium even in emulsion form.

  The amount of the solvent used includes the cationically polymerizable compound (A), the cationic polymerization initiator (B), the acid acceptor (C), and the binder (D) contained as necessary, the radically polymerizable compound (E ) And the radical polymerization initiator (F) in the range of 1 to 1500 parts by weight with respect to 100 parts by weight in total.

  Examples of the thermal polymerization inhibitor include hydroquinone, p-methoxyphenol, tert-butylcatechol, naphthylamine, diphenylpicrylhydrazine, diphenylamine and the like, which have a function of eliminating the generated polymerization active species.

  Examples of chain transfer agents include α-methylstyrene dimer, 2-mercaptobenzoxazole, 2-mercaptobenzothiazole, tert-butyl alcohol, n-butanol, isobutanol, isopropylbenzene, ethylbenzene, chloroform, methyl ethyl ketone, propylene, chloride. Vinyl etc. are mentioned.

[Preparation of photopolymer composition for hologram recording material]
To prepare the hologram recording material composition, the cationically polymerizable compound (A), which is an essential component, a cationic polymerization initiator (B) that generates an acid, and an acid acceptor (C), are optional components. The binder (D), radical polymerizable compound (E), radical polymerization initiator (F), photosensitizing dye (G), etc. are placed in an organic solvent resistant container such as a glass beaker and the whole is stirred. In this case, in order to promote dissolution of the solid component, it may be heated to, for example, about 40 to 90 ° C. within a range in which the composition is not denatured. Moreover, when using an inorganic compound for an acid acceptor (C), since it may be hard to mix with another component, you may mix, after previously dissolving in a good solvent. Moreover, you may use machines, such as a ball mill and a homogenizer.

[Method for producing hologram recording medium]
In order to produce a hologram recording medium using the photopolymer composition for hologram recording material according to the present invention, the recording material composition is applied to one side of a substrate, and the resulting coating film, that is, two layers comprising a recording layer and a substrate. A recording medium having a structure is obtained. If necessary, a three-layer structure is obtained by covering a recording layer on the substrate with a film-like, sheet-like or plate-like protective material. It is preferable to use an organic solvent in the preparation process of the composition. In this case, the cation polymerizable compound (A), the cation polymerization initiator (B), the acid acceptor (C), and optionally all the binder (D), radical polymerizable compound (E), radical polymerization initiator ( F) and the above optional additional components including photosensitizing dye (G) are dissolved in a solvent, and the resulting solution is applied onto a substrate, and then the solvent is stripped to form a recording layer. When covering the recording layer with a protective material, it is preferable to remove the solvent by air drying, evaporation under reduced pressure or the like before coating the protective material. The substrate is made of an optically transparent material, for example, a glass plate, a polyethylene terephthalate plate, a polycarbonate plate, a plastic plate such as a polymethyl methacrylate plate, or a film. The thickness of the substrate is preferably 0.02 to 10 mm. The substrate does not have to be flat, and may be bent, curved, or have an uneven structure on the surface. The protective material is also made of an optically transparent material like the substrate. The thickness of the protective material is preferably 0.02 to 10 mm. Examples of the coating method include gravure coating, roll coating coating, bar coating coating, and spin coating coating. The thickness of the recording layer after removal of the solvent is 1 to 1000 μm, preferably 10 to 100 μm.

[Hologram recording method]
Using a hologram composition containing an acid acceptor, for example, a hologram can be produced by the following recording method.
In order to record the recording object as a hologram on the hologram recording medium according to the present invention, a normal recording method can be adopted. That is, the light having a wavelength in the range of 200 to 800 nm is divided into two, one of which (reference light) and the reflected light from the object (object light) obtained by irradiating the object to be recorded with the other light beam. ) And (or transmitted light (object light) from a master hologram obtained by irradiating the volume phase type master hologram on which information on the object has been recorded in advance with the other light beam) on the same plane, respectively. Alternatively, the medium for hologram recording material is arranged at a position where interference fringes obtained by making the light incident from the front and back surfaces can interfere with each other, and the object is recorded on the medium.

More specifically, the laser beam is divided into two light beams by a beam splitter or the like, and interference fringes are obtained by combining them again by using a mirror or the like (two-beam exposure method). Alternatively, one laser beam is reflected by a mirror, and interference fringes are obtained by combining both incident light and reflected light again (one-beam exposure method). When obtaining an interference pattern, a separately created hologram may be arranged on the optical path as a master hologram, and interference fringes may be obtained by a one-beam and / or two-beam exposure method. The recording medium is installed at a position where the intensity distribution of the interference pattern formed in this way can be captured. In this state, when laser light irradiation is usually performed for several seconds to several minutes, interference fringes that become holograms are recorded on the recording medium. The amount of laser light used is represented by the product of the light intensity and the irradiation time, and is preferably 0.1 to 10,000 mJ / cm ² , more preferably 1 to 1,000 mJ / cm ² .

  The light source used in the present invention is accompanied by electron transfer when light emitted from the light source is irradiated to a photopolymerization initiator comprising a photopolymerization initiator or a combination of a photopolymerization initiator and a photosensitizing dye. Any material that induces polymerization may be used. Typical examples of the light source include a high pressure mercury lamp, an ultra high pressure mercury lamp, a low pressure mercury lamp, a xenon lamp, and a metal halide lamp. These can be used when copying the information of the master hologram to the recording medium. They can also be used as a light source for fixing a hologram on which interference fringes are recorded. As a preferred light source, a laser can be used. A laser has a single wavelength and has coherence, and therefore is a preferable light source for hologram recording. A more preferable light source is a light source excellent in coherence, for example, a laser in which an optical element such as an etalon is attached to the laser, which is obtained by changing the frequency of the single wavelength to a single frequency. Typical lasers have an oscillation wavelength of 200 to 800 nm, specifically Kr (wavelength 647 nm), He-Ne (wavelength 633 nm), Ar (wavelength 514.5, 488 nm), YAG (wavelength 532 nm), He- Examples thereof include Cd (wavelength 442 nm). These light sources may be used alone or in combination of two or more. Further, the light source may be continuous light or may oscillate in pulses at a constant or arbitrary interval. The light obtained from the light source may be applied to the recording material before and after recording as well as during recording.

  After hologram formation, post-processing such as development and fixing is important for stabilizing the formed image and improving the weather resistance of the recorded hologram, and remains after light irradiation or heat treatment on the entire surface. It is preferable to post-polymerize the unreacted monomer.

[Action]
The recording material composition of the present invention contains a cationic polymerizable compound (A), a cationic polymerization initiator (B), and a specific acid acceptor (C) as essential components before exposure, and further includes a binder (D ), A radical polymerizable compound (E), a radical polymerization initiator (F), and a photosensitizing dye (G) can be included as optional components and are compatible as a whole.

  By irradiating the composition with coherent light, either the cationic polymerization initiator (B) or the optional radical polymerization initiator (F) is selectively excited to polymerize. When active species are generated and the polymerization active species is an acid, the cationic polymerizable compound (A) is selectively used. When the polymerization active species is a radical, the radical polymerizable compound (E) is selectively used in the bright part of the interference fringes. To form a latent hologram image. At this time, it is considered that from the dark part to the bright part of the interference fringes, the monomer of the polymerization that has progressed in the bright part diffuses due to the concentration gradient, resulting in a difference in density and refractive index.

  Here, when the photosensitizing dye (G) is contained in the light-sensitive material, the photosensitizing dye (G) absorbs light, and the cationic polymerization initiator (B) or the radical polymerization which is an optional component is started. Only one of the agents (F) is selectively spectrally sensitized to generate polymerization active species, and a hologram latent image is similarly formed. When onium salts that generate radicals and cations at the same time are used as the cationic polymerization initiator (B) or the radical polymerization initiator (F), the cationic polymerizable compound (A) and the radical polymerizable compound (E) Using either of these reactivity differences, either one is preferentially photopolymerized to form a hologram latent image.

  In addition, as a method for selectively exciting the initiator, the difference in the absorption wavelength of the initiator (wavelength selectivity) and the relationship between the oxidation and reduction potential of the initiator and the photosensitizing dye are used.

  After the hologram latent image is formed by the above means, the entire surface is exposed to light sensitive to the cation initiator and the radical polymerization initiator to fix the hologram image.

  By the way, the acid generated from the cationic polymerization initiator (A) is present in the hologram recording layer after the series of hologram recording / fixing operations. For this reason, there is a problem in terms of safety such that the corrosiveness when the hologram is bonded to another base material (for example, metal) and the possibility of causing inflammation when contacting the skin.

  The problem is solved by neutralizing or adsorbing the remaining acid with a specific acid acceptor (C). As the acid-accepting agent (C), one that exhibits an acid-accepting effect slowly after fixing without inhibiting cationic polymerization by an acid during hologram recording or fixing is used. For example, the metal alkoxide described above is gradually hydrolyzed by moisture in the air to generate a base and neutralize the acid. Layered compounds such as hydrotalcite adsorb acid, but the rate of acid adsorption in the system is significantly slower than that of cationic polymerization and does not inhibit cationic polymerization. In addition, a compound having a large steric hindrance such as a hindered amine is the same, and an acid accepting effect appears after the cationic polymerization has sufficiently progressed. That is, as an acid acceptor (C) in the hologram medium, a compound having an acid accepting effect that does not inhibit cationic polymerization during hologram recording or fixing processing is added in a state of being compatible with or uniformly dispersed with other components. Accordingly, a hologram free from problems such as acid corrosion and safety can be produced without deteriorating the recordability of the hologram and the weather resistance of the recorded hologram.

Hereinafter, the present invention will be specifically described with reference to several examples of the present invention. However, these examples do not limit the present invention.
[Example 1]
1) 0.59 g of diphenyliodonium salt (manufactured by Midori Chemical Co., “BBI-102”) as the cationic polymerization initiator (B), and divinyl ether monomer (manufactured by Osaka Gas Co., “OKP”) as the cationic polymerizable compound (A). -4 ”, 4.4 g of a single refractive index: 1.62), 5.0 g of a methyl methacrylate polymer (manufactured by Wako Pure Chemical Industries, Ltd.,“ methyl methacrylate polymer ”, polymer refractive index: 1.49) as a binder (D), Polymerization degree 500, polymer refractive index: 1.43) 5.0 g, photosensitizing dye (G), ketocoumarin-based dye (NKX-653, Nippon Photosensitive Dye Co., Ltd.) 0.007 g, plasticizer, diethyl sebacate ( 4.0 g of “SDE” manufactured by Wako Pure Chemical Industries, Ltd., refractive index: 1.43) and 20 g of acetone as a solvent were mixed at room temperature. Then, as the acid acceptor (C), a solution obtained by dissolving 0.11 g of diethoxycalcium (manufactured by Kosei Chemical Co., Ltd., diethoxycalcium) into 4 g of methyl cellosolve using a homogenizer is mixed, and a photopolymer composition for hologram recording material I adjusted things.
2) This composition is applied to one side of a 60 mm × 60 mm glass substrate by spin coating so that the thickness after drying is 10 to 15 μm, and the solvent is removed from the coating layer by heat treatment, and the substrate and recording A recording medium having a two-layer structure composed of layers was prepared.
3) A hologram recording photosensitive plate having a three-layer structure was prepared by covering the recording layer of this recording medium with a 50 μm thick PET film.
4) Next, a 488 nm Ar ion laser was branched by a beam splitter, and each of them was changed in angle by a mirror. The photosensitive plate was installed at a position where the interference fringes can be captured.
5) Examples of transmission holograms and reflection holograms are shown in FIGS. 1 and 2, respectively.
6) In this state, the photosensitive plate was exposed, and interference fringes to be a hologram were recorded on the photosensitive plate. Exposure of transmission hologram and the reflection hologram, one of the light intensity on the photosensitive plate as 0.5 mW / cm ^2, 160 seconds for 5 seconds, an exposure amount as 2.5 mJ / cm ² from a performed 80 mJ / cm ^2.
7) For fixing the hologram latent image, the whole was irradiated from the ³ J / cm ² PET film side at 10 mW / cm ² using a high-pressure mercury lamp (UMI-102, UM-102).

[Example 2]
1) As cationic polymerization initiator (B), 0.75 g of triphenylsulfonium salt (manufactured by Asahi Denka Kogyo Co., Ltd., “SP-150”) and as cationically polymerizable compound (A), 3,4-epoxycyclohexylmethyl 3, 4-Epoxycyclohexanecarboxylate (manufactured by Bantico, “CY-179”, single-body refractive index: 1.50) and 0.5 g of di [1-ethyl (3-oxetanyl)] methyl ether (manufactured by Toagosei Co., Ltd., “OXT”) -221 ", 4.5g of single refractive index: 1.45), and polymer of dimethyl succinate and 4-hydroxy-2,2,6,6, -tetramethyl-1-piperidineethanol as acid acceptor (C) (Ciba Specialty Chemicals, "TINUVIN622LD") 0.5g, as binder (D), vinyl acetate polymer (Kishida Chemical, "vinyl acetate polymer", polymer refractive index: 1.43) 5.0g, Radical polymerizable compound (E) As a radical polymerization initiator (F), 3.0 g of phenoxyethyl acrylate (Kyoeisha Chemical Co., Ltd., “Light Acrylate PO-A”, single-body refractive index: 1.52), 3,3 ′, 0.8g of toluene solution (purity 25%) of 4,4'-tetra- (t-butylperoxycarbonyl) benzophenone (manufactured by NOF Corporation, “BTTB25”) as a photosensitizing dye (G), cyanine dye ( A photopolymer composition for a hologram recording material was prepared by mixing 0.007 g of NK-1538) manufactured by Nippon Photosensitive Dye Co., Ltd. and 20 g of acetone as a solvent at room temperature.
The same operation as in Example 1 was performed except that a 514.5 nm Ar ion laser was used as the hologram recording laser.

[Example 3]
The PET film was peeled off from the reflection hologram obtained in Example 1 (diffraction efficiency: 56%, reproduction wavelength: 481 nm) (layer structure: PET / recording layer / glass substrate from above), and an adhesive film (manufactured by Sumitomo 3M, Scotch clear tape, “CK-24”) was bonded so that the adhesive layer adhered to the hologram layer. Hologram performance such as diffraction efficiency and reproduction wavelength was maintained even when an adhesive film was laminated. The reason why the hologram performance does not change due to the adhesion of the adhesive is that there is almost no unreacted component remaining in the hologram film, and the acid acceptor does not inhibit the cationic polymerization during recording or fixing. This is because the.

[Example 4]
The same adhesive film as in Example 3 was bonded to the reflection hologram obtained in Example 2 (diffraction efficiency: 84%, reproduction wavelength: 478 nm). Hologram performance, such as diffraction efficiency and reproduction wavelength, was maintained even when an adhesive film was laminated, indicating that almost no unreacted components remained in the hologram film.

[Example 5]
An adhesive film similar to that in Example 3 is bonded to the reflection hologram obtained in Example 1 (layer structure: PET / adhesive layer / recording layer / glass substrate from above), and the PET film derived from the adhesive film is peeled off from here. , Aluminum vapor-deposited film (Kimura Aluminum Foil Co., Ltd., no polycoat) was laminated so that the aluminum vapor-deposited surface was adhered to the adhesive layer (layer structure: PET / aluminum vapor-deposited layer / adhesive layer / recording layer / glass substrate from above) ). This sample was placed in an environment of 40 ° C./90% RH for 10 days. When the appearance of the aluminum layer of the sample exposed to this high temperature and high humidity environment for a long time was examined, there was no change. This shows that the aluminum deposition layer was not eroded by the acid.

[Example 6]
In the same manner as in Example 5, an adhesive film and an aluminum vapor deposition film were bonded to the reflection hologram obtained in Example 2. The samples were placed in an environment of 40 ° C./90% RH for 10 days. When the appearance of the aluminum layer of the sample exposed to this high temperature and high humidity environment for a long time was examined, there was no change. This shows that the aluminum deposition layer was not eroded by the acid.

[Comparative Example 1]
The acid acceptor (C) was not added in the formulation of Example 1. All other points were the same as in Example 1.

[Comparative Example 2]
The acid acceptor (C) was not added in the formulation of Example 3. All other points were the same as in Example 3.

[Comparative Example 3]
The same adhesive film as in Example 3 was bonded to the reflection type hologram (diffraction efficiency: 53%, reproduction wavelength: 480 nm) obtained in Comparative Example 1. Hologram performance such as diffraction efficiency and reproduction wavelength was maintained even when an adhesive film was laminated. Whether or not an acid acceptor was added, the reactivity of the cationic polymerizable compound was not changed.

[Comparative Example 4]
The same adhesive film as in Example 4 was bonded to the reflection hologram obtained in Comparative Example 2 (diffraction efficiency: 86%, reproduction wavelength: 478 nm). Hologram performance such as diffraction efficiency and reproduction wavelength was maintained even when an adhesive film was laminated. Whether or not an acid acceptor was added, the reactivity of the cationic polymerizable compound was not changed.

[Comparative Example 5]
In the same manner as in Example 5, an adhesive film and an aluminum vapor deposition film were bonded to the reflection hologram obtained in Comparative Example 1. This sample was placed in an environment of 40 ° C./90% RH for 10 days. When the appearance of the aluminum layer of the sample exposed to this high temperature and high humidity environment for a long time was examined, the aluminum vapor deposition layer had a small hole. This is because the aluminum deposition layer was eroded by acid.

[Comparative Example 6]
An adhesive film and an aluminum vapor deposition film were bonded to the reflective hologram obtained in Comparative Example 2 in the same manner as in Example 6. This sample was placed in an environment of 40 ° C./90% RH for 10 days. When the appearance of the aluminum layer of the sample exposed to this high temperature and high humidity environment for a long time was examined, the aluminum vapor deposition layer had a small hole. This is because the aluminum deposition layer was eroded by acid.

Performance Evaluation Regarding the holograms obtained in the above examples and comparative examples, the sensitivity during recording, the film thickness of the hologram after recording, the diffraction efficiency, the reproduction wavelength (for the reflective hologram), and the visible light transmittance (for the reflective hologram) ) Was measured.
a) Film thickness The film thickness of the hologram after recording was measured using a micrometer.
b) Diffraction efficiency The diffraction efficiency of the transmission hologram was calculated from the following equation by taking the ratio of the incident light and the diffracted light with an optical power meter (manufactured by PHOTODYNE, OPTICAL POWER / ENERGY METER, MODEL 66XLA).
Diffraction efficiency (%) = (diffracted light intensity / incident light intensity) × 100
c) The diffraction efficiency, reproduction wavelength, and visible light transmittance of the reflection hologram were determined by measuring the transmittance with an ultraviolet-visible spectrophotometer ("V-550" manufactured by JASCO Corporation). FIG. 3 shows a method for calculating diffraction efficiency, reproduction wavelength, and visible light transmittance. When the obtained reflection hologram was measured using an ultraviolet-visible spectrophotometer, a chart as shown in FIG. 3 was obtained. In the figure, (T) is the visible light transmittance, (P) is the intensity of the diffracted light, and (λ) is the reproduction wavelength where (P) is the maximum (D). The diffraction efficiency of the reflection hologram was calculated from the following equation based on the intensity of diffracted light with respect to visible light transmittance other than the reproduction wavelength.
Diffraction efficiency (%) = diffracted light intensity (P) / visible light transmittance (T) × 100

The obtained results are summarized in Table 1.
As is apparent from Table 1, the recording properties of the transmission hologram and the reflection hologram obtained in Examples 1 and 2 are not different from those obtained in Comparative Examples 1 and 2. Also, in terms of curability, the results of Examples 3 and 4 were not changed to Comparative Examples 3 and 4, indicating that sufficient curing was performed even in the formulation containing the acid acceptor. In Examples 5 and 6, there was no change in the laminated aluminum vapor-deposited layer, whereas in Comparative Examples 5 and 6, small holes were formed in the aluminum vapor-deposited layer, and corrosion of aluminum by acid occurred.

  As described above, the hologram photosensitive material containing an acid acceptor as described in the examples does not corrode metal even when the recorded hologram is bonded to aluminum or the like, and causes inflammation due to contact with the skin or the like. It is less dangerous. In addition, the acid acceptor exhibits the same recordability as the hologram photosensitive material in which the acid acceptor of the comparative example is not added without interfering with interference fringe recording, and the acid acceptor does not inhibit the cationic polymerization. The reaction component did not remain in the photosensitive material. Thus, the acid acceptor could improve the corrosion and danger due to the acid, which had been a problem, without degrading the basic performance of the hologram sensitive material and the durability of the completed hologram.

In the table,
・ OKP-4: Divinyl ether monomer (Osaka Gas Co., Ltd.)
・ CY-179: 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate (Bantico)
・ OXT-221: Di [1-ethyl (3-oxetanyl)] methyl ether (manufactured by Toa Gosei Co., Ltd.)
・ BBI-102: Diphenyliodonium salt (Midori Chemical Co., Ltd.)
・ SP-150: Triphenylsulfonium salt (Asahi Denka Kogyo Co., Ltd.)
・ TINUVIN622LD: Polymer of dimethyl succinate and 4-hydroxy-2,2,6,6, -tetramethyl-1-piperidineethanol ・ PO-A: Phenoxyethyl acrylate (manufactured by Kyoeisha Chemical Co., Ltd.)
-BTTB25: 3,3 ', 4,4'-tetra- (t-butylperoxycarbonyl) benzophenone in toluene solution (purity 25%) (manufactured by NOF Corporation)
・ NKX-653: Ketocoumarin dye (manufactured by Nippon Photosensitizer)
・ NK-1538: Cyanine dye (manufactured by Nippon Photosensitizer)
・ SDE: Diethyl sebacate (Wako Pure Chemical Industries)

  The composition for a hologram recording material according to the present invention can be used in the field of producing a hologram medium having sufficient recording properties and weather resistance. In addition, toys such as a seal with a holography can be produced with high safety because it does not cause acid irritation even when it comes into contact with the skin. It can be used for applications.

It is the schematic which showed the example of the transmission hologram. It is the schematic which showed the example of the reflection type hologram. It is the conceptual diagram which showed the calculation method of diffraction efficiency.

Explanation of symbols

(A): Laser generator (BS): Beam splitter (M): Mirror (S): Photosensitive plate (B1): Object light (B2): Reference light

Claims (7)

  A photopolymer composition for a hologram recording material, comprising as an essential component a cationically polymerizable compound (A), a cationic polymerization initiator (B), and a specific acid acceptor (C).   Furthermore, binder (D) is contained, The photopolymer composition for hologram recording materials of Claim 1 characterized by the above-mentioned.   The photopolymer composition for a hologram recording material according to claim 1, further comprising a radical polymerizable compound (E) and a radical polymerization initiator (F).   4. The photopolymer composition for hologram recording material according to claim 1, further comprising a photosensitizing dye (G).   5. The photopolymer composition for a hologram recording material according to claim 1, wherein the acid acceptor (C) is a metal alkoxide or a hindered amine.   A hologram recording medium comprising a substrate and a recording layer comprising the hologram recording material composition according to claim 1. The method for producing a hologram recording medium according to claim 6, wherein the photopolymer composition according to any one of claims 1 to 5 is dissolved in a solvent, the resulting solution is applied onto a substrate, and then the solvent is stripped to form a recording layer. .

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