KR101024744B1 - Photosensitive resin composition for volume phase hologram recording and optical information recording medium using same - Google Patents

Abstract

A volume phase hologram recording material, a volume phase hologram recording medium, and a volume phase hologram having excellent transparency, sensitivity, low curing shrinkage ratio, and transparency. The photosensitive resin composition for volume phase hologram recording is copolymerized with a low molecular weight solvent soluble aromatic copolymer (A) and a soluble aromatic copolymer (A) having a structural unit of a divinyl aromatic compound and a structural unit of a monovinyl aromatic compound. A photosoluble resin composition comprising a photoradical polymerizable compound (B) and a photopolymerization initiator (C) as an essential component, and containing at least one of a polymer binder (D) and a plasticizer (E). 5 to 60% by weight of coalescing (A) is included.

Soluble aromatic copolymer, optical radical polymerizable compound, photopolymerization initiator, polymer binder, plasticizer

Description

PHOTOSENSITIVE RESIN COMPOSITION FOR VOLUME PHASE HOLOGRAM RECORDING AND OPTICAL INFORMATION RECORDING MEDIUM USING SAME}

According to the present invention, a volume phase hologram capable of forming a thick film by photocuring rapidly by an active energy ray (visible light laser, ultraviolet ray, electron beam, etc.), having good hologram characteristics such as diffraction efficiency and resolution, and excellent transparency and heat resistance A photosensitive resin composition for volume phase hologram recording, which is very suitable as a material of the present invention, and an optical information recording medium using the same.

Conventionally, holograms have been mainly used in the field of stereoscopic image display and security. As the hologram material, a wet type material which requires a development such as silver salt photosensitive material or dichromate gelatin has been mainly used, but since then, it is a dry type having excellent environmental resistance and light resistance after recording that does not require development treatment. Photopolymerization hologram recording materials have become mainstream. Unlike the silver salt photosensitive material, the dichromate gelatin, etc., the recording mechanism of a photopolymerization hologram recording material is generally considered as follows. In other words, when an interference pattern made of light interference having excellent coherence (coherence) is irradiated onto the recording material, the light (a strong light intensity area) and the dark part of the light are exposed. A substance having different polymerizability is diffused and moved in the (light intensity region), and a hologram is recorded by forming a refractive index modulation structure with the progress of photopolymerization. Examples of the polymerization form of the photopolymerization hologram recording material include 1) radical polymerization type, 2) cationic polymerization type, and 3) radical / cationic polymerization combination type. Although a photoradical polymerization type material is common, the sensitivity is high, but there is a drawback that the shrinkage due to the polymerization type is several percent. At present, the only photosensitive resin composition commercially available among photopolymerization hologram recording materials is OMNIDEX manufactured by DuPont, USA.

In recent years, in order to realize the ubiquitous information society, researches on using photopolymerization hologram recording materials for holographic data storage have been revived in the world, and various photopolymerization hologram recording materials have been proposed. This is due to the development of national projects such as HDSS (Holographic Date Storage System: 1995-1999) and PRISM (Photorefractive Information Storage Materials: 1994-1998), which began in the United States from the mid-1990s. The leap forward makes a great contribution. Conventional recording on an optical disc such as a CD or a DVD takes a method of condensing a laser beam with a lens to record data bit by bit on a recording material surface. The theoretical limit of the data storage capacity determined by the size of the condensed spot has already reached its limit, and new techniques are required to further increase the storage capacity. One of the candidates is holography.

Holographic data storage can record in volume rather than in-plane recording such as CD and DVD, and the data to be handled uses page data, so recording of large amounts of data incomparable with conventional CDs and DVDs It is possible. At present, for the practical use of WORM (write once read many) recordable hologram optical discs capable of recording 1 TB (terabytes), materials development and recording technology development are actively performed in each research institute. The way of thinking about the basic design of the holographic data storage material is the same as that of the above-mentioned photopolymerization hologram recording material for stereoscopic image recording and security. However, when used for holographic data storage applications, the demands on the material for the sensitivity and hardening shrinkage of the light source to be used are particularly severe. As a typical example of this photosensitive resin composition for holographic data storage, the American Aprilis which inherited the American Polaroid company, and the American InPhase company which inherited the American Lucent Technology company are mentioned.

First, US Aprilis, for example, as described in Patent Documents 1 and 2, CROP (Cationic Ring-Opening Polymerization) monomers having oxirane and oxetane rings The material which suppressed the polymerization shrinkage rate by using pre-photoirradiation is disclosed. However, cationic polymerization has a problem that the oxygen inhibition such as radical polymerization is small, but the sensitivity in the long wavelength region is slightly inferior. On the other hand, in U.S. Inface Co., for example, as described in Patent Documents 3, 4 or 5, polymerization shrinkage is achieved by using a cyclohexene oxide and an expanding agent (diphenylfuran carboxylate) in combination. An extremely small material of less than 1% is disclosed. However, here too, curing shrinkage is suppressed by using a cationic ring-opening polymerizable monomer and exposing the whole surface before or after recording, but there is no proposal for improving the sensitivity. For the practical use of holographic data storage, further improvement in light sensitivity, reduction in curing shrinkage rate, and improvement in heat resistance are desired.

Patent Document 1: US Patent No. 5,759,721

Patent Document 2: US Patent No. 6,784,300

Patent Document 3: US Patent No. 3,993,485

Patent Document 4: US Patent No. 6,124,076

Patent Document 5: Japanese Unexamined Patent Publication No. 2000-086914

Patent Document 6: Japanese Patent Application Laid-open No. Hei 5-94014

Patent Document 7: Japanese Patent Application Laid-Open No. 9-106242

Patent Document 8: Japanese Patent Application Laid-Open No. 2004-123873

Patent documents 6 and 7 describe the photosensitive resin composition for holograms which mix | blended a radically polymerizable ethylene monomer, a photoinitiator, and an epoxy resin. In this composition, the hologram is formed using the phenomenon in which the radically polymerizable ethylene-based monomer preferentially polymerizes from the bright portion of the interference fringe during the holographic exposure by laser, and the ethylene-based monomer moves to the bright portion. In addition, the epoxy resin is then cured. Patent Document 8 describes a soluble aromatic copolymer aromatic copolymer having a structural unit of a divinyl aromatic compound and a structural unit of a monovinyl aromatic compound, but does not disclose the use of holograms.

As a photosensitive resin composition which can record a volume phase hologram, many material systems have been examined and disclosed until now, but there has been no photosensitive resin composition which can satisfy both light sensitivity and cure shrinkage at the same time. When using the resin composition for volume phase hologram recording for holographic data storage, high level is calculated | required especially regarding two things, a light sensitivity and a low hardening shrinkage rate.

The present invention has been accomplished in view of the above circumstances, and has a good diffraction efficiency, resolution, transparency, heat resistance, and the like, which is required for a volume phase hologram, and in particular, a resin composition for volume phase hologram recording excellent in light sensitivity, and the composition. It is to provide an optical information recording medium obtained from. Of course, the hologram obtained by the present invention can be used in applications other than for holographic data storage, for example, in applications in which usefulness is exhibited by using holograms such as diffraction gratings, interference filters, lenses, head-up displays, and the like. .

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining the said subject, the present inventors mix | blend a soluble polyfunctional vinyl aromatic copolymer and the optical radically polymerizable compound copolymerizable with this in a composition, and can further improve photosensitive property and can suppress the shrinkage after hardening more. It has been found that the present invention has been completed.

The present invention is a soluble aromatic copolymer (A) having a structural unit of a divinyl aromatic compound and a structural unit of a monovinyl aromatic compound and containing 10 mol% or more of the structural unit represented by the following formula (a1), and a soluble aromatic air A soluble aromatic copolymer (A) as a photosensitive resin composition comprising an optical radical polymerizable compound (B) and a photopolymerization initiator (C) copolymerizable with the copolymer (A) and a polymer binder (D) and / or a plasticizer (E). 5 to 60% by weight of the photosensitive resin composition for volume phase hologram recording.

(In formula, R <^1> represents a C6-C30 aromatic hydrocarbon group.)

The present invention is also an optical information recording medium for volume phase hologram recording in which a recording layer made of the photosensitive resin composition is formed on one support or between two supports. Furthermore, the present invention is a volume phase hologram obtained by recording an interference fringe formed from an energy ray having excellent coherent property on the optical information recording medium. Further, the present invention is a method for producing a volume phase hologram, characterized in that the recording medium is subjected to exposure recording of an interference fringe formed from an energy ray having excellent coherent properties.

The photosensitive resin composition of this invention is a resin composition for volume phase hologram recording used for recording the interference pattern which consists of interference of the light excellent in coherence as a stripe with a different refractive index, and is a soluble aromatic copolymer (A), An optical radically polymerizable compound (B) and a photoinitiator (C) are included as an essential component, and a polymeric binder (D), a plasticizer (E), or both are included as an essential component.

First, a soluble aromatic copolymer (A) is demonstrated.

A soluble aromatic copolymer (A) is obtained by copolymerizing a divinyl aromatic compound and a monovinyl aromatic compound, and has 10 mol% or more of the structural unit containing a reactive vinyl group in the side chain represented by said formula (a1). The structural unit represented by formula (a1) is derived from the divinyl aromatic compound as a monomer. Advantageously, the structural unit represented by formula (a1) has an average of 3 or more in one molecule. And a soluble aromatic copolymer (A) is a well-known compound described in patent document 8 etc., and is manufactured suitably by the method described there.

Examples of the divinyl aromatic compound include m-divinylbenzene, p-divinylbenzene, 1,2-diisopropenylbenzene, 1,3-diisopropenylbenzene, and 1,4-diisopropenyl Benzene, 1,3-divinylnaphthalene, 1,8-divinylnaphthalene, 1,4-divinylnaphthalene, 1,5-divinylnaphthalene, 2,3-divinylnaphthalene, 2,7-divinylnaphthalene, 2,6-divinylnaphthalene, 4,4'-divinylbiphenyl, 4,3'-divinylbiphenyl, 4,2'-divinylbiphenyl, 3,2'-divinylbiphenyl, 3, 3'-divinylbiphenyl, 2,2'-divinylbiphenyl, 2,4-divinylbiphenyl, 1,2-divinyl-3,4-dimethylbenzene, 1,3-divinyl-4, 5,8-tributylnaphthalene, 2,2'-divinyl-4-ethyl-4'-propylbiphenyl, and the like can be used, but is not limited thereto. These can be used individually or in combination of 2 or more types.

As a very preferred specific example of the divinyl aromatic compound, divinylbenzene (both m- and p-isomers), divinylbiphenyl (including each isomer) and divinyl naphthalene (in terms of cost and heat resistance of the obtained polymer) Each isomer is included). More preferably, they are divinylbenzene (both m- and p-isomers), and divinyl biphenyl (including each isomer). In particular, divinylbenzene (both m- and p- isomers) is most preferably used.

As a monovinyl aromatic compound, besides styrene, vinyl naphthalene, vinyl biphenyl, etc., these derivatives are mentioned. As a derivative, in addition to the compound which substituted by substituents, such as an alkyl group, an alkoxy group, a halogen, and a phenyl group, in the aromatic ring, the compound which the said substituent substituted in the (alpha) position or (beta) position of a vinyl group is mentioned. In addition, aromatic olefins such as indene and acenaphthylene and derivatives thereof can also be used as the monovinyl aromatic compound. These can be used individually or in combination of 2 or more types.

As the styrene derivative, for example, methyl styrene, ethyl styrene, propyl styrene, butyl styrene, pentyl styrene, hexyl styrene, cyclohexyl styrene, ethoxy styrene, propoxy styrene, butoxy styrene, pentoxy styrene, hex Hexoxy styrene, cyclohexoxy styrene, phenoxy styrene and the like can be used. These substituents may be substituted on o, m or p with respect to the vinyl group, and in the case of having a side chain, may be a linear or branched alkyl or alkoxy group.

As indene or its derivative, indene, a C1-C6 alkyl substituted indene, a C1-C6 alkoxy substituted indene, etc. can be used, for example. Examples of acenaphthylene or derivatives thereof include acenaphthylene, alkyl substituted acenaphthylene having 1 to 6 carbon atoms, halogen substituted acenaphthylene such as phenyl substituted acenaphthylene, chlorine, and bromine.

Monovinyl aromatic compounds are not limited to these. Among these monovinyl aromatic compounds, since the amount of generation of indan structures in the skeleton of the copolymer during polymerization is large, a nucleoalkyl substituted aromatic vinyl compound and an α-alkyl substituted aromatic vinyl compound This is preferred. Very preferred structural examples include ethylvinylbenzene (both m- and p-isomers), ethylvinylbiphenyl (including each isomer) and ethylvinylnaphthalene (including each isomer) in terms of cost and heat resistance of the polymer obtained. There is this.

The soluble aromatic copolymer (A) is obtained by copolymerizing the divinyl aromatic compound and the monovinyl aromatic compound as described above, but other monomers may be used as necessary. As such another monomer, a trivinyl aromatic compound, diene compounds, such as butadiene and isoprene, alkyl vinyl ether, isobutene, diisobutylene, etc. are mentioned. These other monomers are used within the range of less than 30 mol% of all monomers. In addition, the divinyl aromatic compound is used to be 20 mol% or more, preferably 40 to 80 mol% of all monomers, and the monovinyl aromatic compound is 10 mol% or more, preferably 20 to 60 mol% of all monomers. Is used.

As a polymerization method for producing a soluble aromatic copolymer (A), the method of patent document 8 can be mentioned as a preferable example. For example,

Lewis acid catalyst and the following general formula (1) in an organic solvent

(In formula, R <^1> represents a hydrogen atom or a C1-C6 monovalent hydrocarbon group, R <^2> represents a p-valent aromatic hydrocarbon group or an aliphatic hydrocarbon group, Z is a halogen atom, a C1-C6 alkoxyl group, or an acyl jade. The actual group is represented, and p represents an integer of 1 to 6. When there are a plurality of R ¹ and Z in one molecule, each may be the same or different), and the divinyl aromatic compound (a) The monomer component containing 20-100 mol% is cationicly polymerized at the temperature of 20-120 degreeC.

As the organic solvent, at least one organic solvent having a dielectric constant of 2 to 15 is preferable, and is selected from the group consisting of quaternary ammonium salts, C 3 or more ether compounds, C 3 or more thioether compounds, and C 2 or more sulfoxide compounds It is also desirable to have a donor component to be present. As an organic solvent, as long as it is a compound which does not substantially inhibit cationic polymerization, it can be used without restriction | limiting especially, It is good to use it as a polymerization solvent individually or in combination of 2 or more types so that dielectric constant may be in the range of 2-15. Examples of the organic solvent include methyl chloride, dichloromethane, n-propyl chloride, n-butyl chloride, chloromethane, trichloromethane, tetrachloromethane, chloroethane, dichloroethane, trichloroethane, tetrachloroethane, chloroethylene and dichloroethylene Halogenated hydrocarbons such as chlorobenzene, chlorobenzene, dichlorobenzene and trichlorobenzene; Aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, propylbenzene, and butylbenzene; Linear aliphatic hydrocarbons such as ethane, propane, butane, pentane, hexane, heptane, octane, nonane and decane; Branched aliphatic hydrocarbons such as 2-methylpropane, 2-methylbutane, 2,3,3-trimethylpentane and 2,2,5-trimethylhexane; Cyclic aliphatic hydrocarbons such as cyclohexane, methylcyclohexane and ethylcyclohexane; And paraffin oil obtained by hydrogenation of petroleum oil. Of these, dichloroethane, toluene, xylene, pentane, hexane, heptane, octane, 2-methylpropane, 2-methylbutane, methylcyclohexane and ethylcyclohexane are preferable. Dichloroethane, toluene, xylene, n-hexane, cyclohexane, heptane, methylcyclohexane and ethylcyclohexane are more preferable from the viewpoint of the balance of polymerizability, solubility and the availability. The amount of the organic solvent used is usually determined so that the concentration of the polymer is 1 to 50 wt%, preferably 5 to 35 wt% in consideration of the viscosity of the polymer solution obtained and ease of heat removal. If the dielectric constant is less than 2, the polymerization activity is lowered. This is not preferable. In the polymerization, the initiator represented by the general formula (1) is used in an amount of 0.001 to 100 mol, preferably 0.3 to 50 times mol, and a donor component in a range of 0.001 to 10 mol, with respect to 1 mol of the initiator. It is also preferable to polymerize in the organic solvent which melt | dissolves a soluble aromatic copolymer.

Specific examples of Lewis acid catalysts used as polymerization catalysts include boron bromide (III), boron chloride (III), aluminum bromide (III), aluminum fluoride (III), aluminum chloride (III), and aluminum iodide (III). Gallium bromide (III), gallium chloride (III), indium bromide (III), indium chloride (III), indium fluoride (III), indium iodide (III), thallium bromide (III), thallium fluoride (III) , Silicon bromide (IV), silicon chloride (IV), silicon fluoride (IV), silicon iodide (IV), germanium bromide (IV), germanium chloride (IV), germanium iodide (IV), tin bromide (IV), Tin chloride (IV), tin fluoride (IV), tin iodide (IV), lead fluoride (IV), antimony bromide (III), antimony chloride (III), antimony chloride (V), antimony fluoride (III), Antimony fluoride (V), antimony iodide (III), bismuth bromide (III), bismuth chloride (III), bismuth fluoride (III), bismuth iodide (III), Metal halides such as titanium chloride (IV), titanium bromide (IV), BF ₃ · OEt ₂ , tungsten chloride (VI), vanadium (V), iron chloride (III), and zinc (II) bromide; And organometallic halides such as Et ₂ AlCl and EtAlCl ₂ . The said catalyst is not specifically limited, It can use individually or in combination of 2 or more types. Among the catalysts described above, boron bromide (III), boron chloride (III), tin chloride (IV), tin bromide (IV), tin chloride (IV), tin fluoride (IV), tin iodide (IV), and antimony chloride (IV) V) is preferable in view of control of the branch structure and polymerization activity. More preferably, it is boron chloride (III) and tin chloride (IV), Especially preferably, it is tin chloride (IV).

As an initiator represented by General formula (1), it is (1-chloro- (methyl)) benzene, 1, 4-bis (1-chloro- 1-methylethyl) benzene, 1, 3-bis (1). -Chloro-1-methylethyl) benzene, 1,3,5-tris (1-chloro-1-methylethyl) benzene, 1,3-bis (1-chloro-1-methylethyl) -5- (tert- And compounds such as butyl) benzene, 1-chloroethylbenzene, and 1-bromoethylbenzene. Preferred are bis (1-chlor-1-methylethyl) benzene, 1-chloroethylbenzene and 1-bromoethylbenzene.

The polymerization for producing the soluble aromatic copolymer (A) is performed at a temperature in the range of 20 to 100 ° C. If the polymerization reaction is carried out at less than 20 ° C, the heat resistance of the resulting copolymer becomes low, which is undesirable, and if it exceeds 100 ° C, since the reaction rate is too high, it is difficult to control the reaction and formation of an insoluble gel by crosslinking is difficult. It is not preferable because it becomes easy to occur. The method for recovering the copolymer after the completion of the polymerization reaction is not particularly limited. For example, a method commonly used such as a steam stripping method or precipitation in a poor solvent may be employed. You can use

Soluble aromatic polymer (A) is a following formula (a2)

(In formula, R <^4> represents a C6-C30 aromatic hydrocarbon group.) It is preferable to have a structural unit derived from the monovinyl aromatic compound represented by The present molar ratio (a1) / [(a1) + (a2)] of the structural unit to be displayed is 0.1 or more. Preferably it is 0.3 or more, Especially preferably, it is 0.5 or more. If less than 0.1, the recorded hologram is lost with time.

In addition, the soluble aromatic polymer (A) has the following general formula (2) in the main chain skeleton thereof.

(N is an aromatic ring or a substituted aromatic ring condensed to a saturated or unsaturated aliphatic hydrocarbon group or an aromatic hydrocarbon group or a benzene ring, and n is an integer of 0 to 4). It is preferable to have 20 mol%. When the indole structure is prepared by the above production method, the copolymer (A) is produced under a specific solvent, catalyst, temperature, or other production conditions, whereby the active point at the end of the growth polymer chain is divinyl aromatic compound and monovinyl. It produces | generates by attacking the aromatic ring of the structural unit derived from an aromatic compound. It is preferable that the indane structure is present at 0.01 mol% or more with respect to the structural units of all monomers. More preferably, it is 0.1 mol% or more, More preferably, it is 1 mol% or more. Especially preferably, it is 3 mol% or more. Most preferably, it is 5 mol% or more. If the indane structure does not exist in the main chain skeleton of the polyfunctional vinyl aromatic copolymer of the present invention, heat resistance and solubility in a solvent are insufficient, which is not preferable.

The number average molecular weight (based on standard polystyrene conversion obtained by using gel permeation chromatography. Hereinafter, referred to as Mn) of the soluble aromatic copolymer (A) is preferably 400 to 30000. More preferably, it is 400-10000, More preferably, it is 500-5000. When Mn is less than 400, since the viscosity of copolymer (A) is too low, since workability is not good, it is not preferable. In addition, when Mn is 30000 or more, it is not preferable because rapid mass movement during hologram recording is inhibited.

In addition, the value of the soluble aromatic copolymer (A) molecular weight distribution (Mw / Mn) is preferably 10 or less. If Mw / Mn is more than 10, it is not preferable because it causes problems such as deterioration of processing characteristics of the soluble polyfunctional vinyl aromatic copolymer and generation of gel.

Since the soluble aromatic copolymer (A) has a structural unit represented by the formula (a1) having an unsaturated bond, it has polymerizability. And since it is soluble in toluene, xylene, tetrahydrofuran, dichloroethane or chloroform, it is possible to shift so as to resolve the concentration gradient when polymerizing a specific portion as a composition.

Next, an optical radically polymerizable compound (B) is demonstrated.

The radical photopolymerizable compound (B) used in the present invention has good compatibility with the soluble aromatic copolymer (A) and the polymer binder (D) or plasticizer (E) described later, and is an active radical species generated from a radical polymerization initiator. It is good to superpose | polymerize by. Advantageously, the monomer which has at least one polymerizable functional group, such as a (meth) acryloyl group, a vinyl group, an allyl group, can be used suitably in a molecule | numerator. As an optical radically polymerizable compound (B), you may use 2 or more types of optical radically polymerizable compounds from which polymeric property and refractive index differ.

When light is irradiated, the component to superpose | polymerize first (in the list of interference light) is a radical photopolymerizable compound (B) and a soluble aromatic copolymer (A) mainly. The hardened | cured material produced at this time is estimated that the polymer of a soluble aromatic copolymer (A) and the copolymer of an optical radically polymerizable compound (B) and a soluble aromatic copolymer (A) are a main component. However, in the system in which the soluble aromatic copolymer (A) does not exist or in which the aromatic oligomer having no reactive vinyl group is used in place of the soluble aromatic copolymer (A), recording can be performed for a while, but after a while Since the recording is gradually erased when it is left, the soluble aromatic copolymer (A) is considered to play a role of fixing the recording by reacting with the radical photopolymerizable compound (B). Therefore, it is considered that the difference in refractive index occurs between the following components. 1) When a polymer binder (D), a plasticizer (E), or both are used, the rosin is hardened | cured material of a soluble aromatic copolymer (A) and a radical photopolymerizable compound (B) being concentrated (hardened concentrated phase ( ), The dark portion concentrates the polymer binder (D), the plasticizer (E), or both (non-cured concentrated phase), and a difference in refractive index occurs. 2) When using 2 or more types of radical photopolymerizable compounds (B) and using the radical photopolymerizable compound (B2) which is inferior in reactivity compared with reacting in a roster, a dark part is a radical photopolymerizable compound (B2). ), The polymer binder (D), the plasticizer (E) or both are concentrated (dark cured material and non-hardened concentrate phase), whereby a difference in refractive index occurs. Therefore, in the case of 1), the refractive index of the hardened | cured material concentrated phase and the non-hardened concentrated phase needs to differ by more than a fixed value. In the case of 2), the refractive index of the hardened | cured material concentrated phase, the dark hardened | cured material, and the nonhardened concentrated phase needs to differ by more than a fixed value. The refractive index is adjusted by selecting the type and amount of the radical polymerizable compound (B), the polymer binder (D), and the plasticizer (E).

As an example of an optical radically polymerizable compound (B), methyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, ethyl carbitol (meth) Acrylate phenoxyethyl (meth) acrylate, nonylphenoxyethyl (meth) acrylate, dicyclopentenyl (meth) acrylate, isobornyl (meth) acrylate, tribromobenzyl (meth) acrylate, Monofunctional (meth) acrylates such as acryloylmorpholine; Silicon-containing (meth) acrylates such as (meth) acryloxypropyltris (methoxy) silane; Di (meth) acrylates of bisphenol compound alkylene oxide adducts such as bisphenol F, bisphenol A and hydrogenated bisphenol A; Multifunctional (meth) acrylates, such as trimethylol propane tri (meth) acrylate, dipentaerythritol pentaacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, ditrimethylol tetraacrylate, and dipentaerythritol hexaacrylate Rate; Ethylene glycol diglycidyl ether-epoxy (meth) acrylate, propylene glycol diglycidyl ether-epoxy dimethyl (meth) acrylate, phenol glycidyl ether-epoxy (meth) acrylate, resorcin diglycidyl ether Epoxy (meth) acrylate, bisphenol A diglycidyl ether-epoxydi (meth) acrylate, bis (4-hydroxyphenyl) sulfide diglycidyl ether-epoxy (meth) acrylate, phenol novolak Type epoxy resin-(meth) acrylate, cresol novolak-type epoxy resin-(meth) acrylate, bisphenol (for example, bisphenol A, bisphenol F, etc.) type epoxy resin-(meth) acrylate, biphenol (example For example, 3,3 ', 5,5'- tetramethyl biphenol etc.) type epoxy resin-(meth) acrylate, tris (2, 3- epoxypropyl) isocyanurate-(meth) acrylate, etc., Reaction of various known epoxy compounds with (meth) acrylic acid Epoxy (meth) acrylates which are water; Acrylamides such as N, N-dimethylacrylamide and N, N-diethylacrylamide; Vinyl compound of consistent performance such as vinylbenzene, divinylbenzene, vinylnaphthalene, vinylbiphenyl, acenaphthylene, styrene, p-chlorostyrene, N-vinylcarbazole, N-vinylpyrrolidone and N-vinyl caprolactam logistics; Allyl-group containing compounds, such as diallylden pentaerythritol, diallyl phthalate, diallyl isophthalate, ethylene glycol diallyl carbonate, trimellitic acid triallyl ester, and triallyl (iso) cyanurate; Or urethane (meth) acrylates, polyurethane (meth) acrylates, thiourethane acrylates, polythiourethane acrylates, ester acrylates, polyester (meth) acrylates, polyether (meth) ) Well-known various polymerizable monomers, such as an acrylate, containing sulfur (meth) acrylate, and containing sulfur polyfunctional (meth) acrylate, these oligomers, other various photopolymerizable oligomers, etc. are mentioned. Among these, the (meth) acrylate type monomer with favorable photocurability is preferable. In particular, the hologram recordability becomes favorable in the combination of the (meth) acrylate containing the (meth) acrylate more than bifunctional.

Although an optical radically polymerizable compound (B) is mix | blended with a composition and irradiated with light, it superposes | polymerizes and hardens, but some copolymerizes and hardens | cures with a soluble aromatic copolymer (A).

Next, a photoinitiator system (C) is demonstrated.

As the photopolymerization initiator system (C), visible light laser light such as He-Ne laser (633 nm), Ar laser (515, 488 nm), YAG laser (532 nm), He-Cd laser (442 nm), or blue DPSS laser (405 nm) The radical radical may be absorbed to generate a radical, and the active radical species may be an initiator system which polymerizes the soluble aromatic copolymer (A) and the radical photopolymerizable compound (B) which are essential components of the present invention. Moreover, a dye sensitizer can be added for the purpose of further improving the sensitivity in each laser beam wavelength.

As a photoinitiator, For example, 2, 2- diethoxy acetophenone, 2, 2- diethoxy-2-phenyl acetophenone, benzophenone, 1- (4-isopropylphenyl) -2-hydroxy-2- Methylpropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether, 1-hydroxycyclohexyl- Phenyl-ketone, 2,2-dimethoxy-1,2-diphenylethan-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-propane- 1-one, 1- (4-hydroxyethoxy) -phenyl-2-hydroxy-2-methyl-1-propan-1-one, 2-methyl-1- (4- (methylthio) phenyl)- 2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide , Bis (2,6-dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphineoxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (η5-2,4-cyclo Pentadien-1-yl) -r (2,6-difluoro-3- (1H-pyrrol-1-yl) phenyl) titanium, 4,4-bisdimethylaminobenzophenone, methylbenzoisoformate, benzyldimethyl ketal, benzoyl benzoic acid, 4-dimethylamino benzoate, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-diethylthioxanthone, 2,4-dimethylthioxanthone, camphorquinone, benzyl, 4, 4'- diethylamino benzophenone etc. are mentioned. As a commercial item of an optical radical polymerization initiator, Irgacure184, 369, 500, 651, 819, 907, 784, 2959, Darocurl116, 1173 (above, Chiba Specialty Chemicals Co., Ltd.), etc. are mentioned, for example.

Moreover, you may use a thermal polymerization initiator in the form used together with the said photoinitiator. As a thermal polymerization initiator to use together, 2,2'- azobis (2-methylbutylonitrile), 2,2'- azobisisobutylonitrile, 2,2'- azobisiso Valeronitrile (azobisisovaleronitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 1,1'-azobis (cyclohexane-1-carbonitrile), methylethylketone peroxide, methyliso Butyl ketone peroxide, benzoyl peroxide, 2, 4- dichloro benzoyl peroxide, etc. are mentioned.

Since the addition amount of these initiators changes with kinds of initiator, the kind of compound to mix | blend, and composition ratio, it cannot determine uniformly, but the range of 0.05-30 weight% is preferable with respect to the photosensitive resin composition whole quantity. Especially preferably, it is the range of 0.1-8 weight%. If it is less than 0.05% by weight, the curability is inferior, an unreacted substance remains, and the recording stability is poor. Moreover, when it exceeds 30 weight%, since a polymerization degree will become low, hardened | cured material will become too flexible, and transparency may fall in some cases, and it is unpreferable. In the case of 0.1 to 8 weight%, sclerosis | hardenability is especially favorable and the photosensitive resin composition with favorable hologram characteristics can be provided.

When using a dye sensitizer, what is necessary is just to exhibit absorption to the light of a visible region as a dye sensitizer, and it is a (thio) xanthene type pigment | dye, a cyanine pigment | dye, a merocyanine pigment | dye, squallium pigment | dye, tea Known compounds such as thiopyrylium salt pigments, quinoline pigments, (base) styryl pigments, (keto) coumarin pigments, rhodacyanine pigments, porphyrin pigments, and oxazine pigments Can be mentioned. These may be used independently or may be used in combination of 2 or more.

In the present invention, the polymer binder (D) can be used, for example, for the purpose of improving film-forming properties and film strength that can also be applied to thick films, or to increase the environmental resistance after hologram recording. As the polymer binder (D) used for this purpose, preferably, one having high transparency and one having high compatibility with the soluble aromatic copolymer (A) is preferable. For example, polystyrene and its derivatives, methyl methacrylate-styrene copolymer (MS resin), styrene-acrylonitrile copolymer (AS, SAN resin), poly (4-methylpentene-1) (TPX resin), Polycycloolefin (COP resin), polydiethylene glycol bisallylcarbonate (EGAC resin), polythiourethane (PTU resin), polymethyl vinyl ether (PMVE resin), polysulfone resin, polyvinyl acetate, polyvinyl alcohol, poly Vinylpyrrolidone, acetyl cellulose, and the like. The polymer binder (D) may have a reactive group such as a cationically polymerizable group in the side chain or the main chain thereof. These can mix | blend one or more types.

In this invention, a plasticizer (E) can be used as a compound which improves the mass transfer of the soluble aromatic copolymer (A), the radical photopolymerizable compound (B), or the compatibility of the photosensitive resin composition. As the plasticizer (E), one having high compatibility with the aromatic copolymer (A) and the radical photopolymerizable compound (B) and a liquid phase that facilitates material movement during recording is very preferably selected. For example, sebacic acid esters, such as dimethyl sebacate, diethyl sebacate, dibutyl sebacate, and bis (2-ethylhexyl) sebacate; Adipic acid esters such as dimethyl adipate, diethyl adipate, dibutyl adipate and bis (2-ethylhexyl) adipate; Phthalic acid esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, bis (2-ethylhexyl) phthalate and diisodecyl phthalate; Phosphoric acid esters such as trimethyl phosphate, triethyl phosphate, tributyl phosphate, (2-ethylhexyl) phosphate, triphenyl phosphate, cresyl diphenyl phosphate and tricresyl phosphate; Known plasticizers (E) such as these can be used. These can be used by one or more types.

In addition, if necessary, a thermal polymerization inhibitor, a chain transfer agent, an antioxidant, a silane coupling agent, a drawing improving agent, a surface conditioner, a plasticizer, an antifoaming agent, a surfactant, a colorant, a storage stabilizer, a ultraviolet absorber, a thickener and the like A well-known additive (F) can also be added.

In the case where the resin composition in the present invention is a solid or when coating with high viscosity is difficult, a solvent (G) can be used to dissolve or disperse the resin composition. For example, ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; Esters such as ethyl acetate and butyl acetate; Petroleum solvents such as toluene and xylene; Cellosolves such as methyl cellosolve, ethyl cellosolve and butyl cellosolve; Alcohols such as ethanol, methanol, isopropanol and butanol; Ethers such as tetrahydrofuran and dioxane; Halogenated hydrocarbons, such as dichloromethane and chloroform, are mentioned. The solvent is preferably 200 parts by weight or less, more preferably 100 parts by weight or less per 100 parts by weight of the resin solid component. Moreover, in order to raise the efficiency of a later drying process, it is preferable that the boiling point is 100 degrees C or less. In addition, a solvent (G) is a component for melt | dissolving or disperse | distributing a resin composition, and is not a component of the resin composition in this invention, and is excluded in calculation of content of each component.

In addition, although the component used as an essential component in the composition of this invention is (A)-(C) and (D) or (E), it is preferable to use both (D) and (E). In addition, in description of the said component, another component (F), etc., and a solvent (G), these are not limited to what was illustrated.

Composition of Hologram Recording Material

It is preferable that the photosensitive resin composition for volume phase hologram recording of this invention mix | blends each component with the following ratio with respect to the composition total weight (excluding a solvent).

5 to 60% by weight, preferably 10 to 40% by weight of the soluble aromatic copolymer (A)

5-50% by weight of the radical photopolymerizable compound (B), preferably 10-40% by weight

0.05-30 weight% of photoinitiators (C), Preferably 1-10 weight% (When mix | blending a dye sensitizer, it is 0.01-10 weight% and a total amount with a photoinitiator is 30 weight% Not exceed)

0-50% by weight of polymer binder (D), preferably 10-40% by weight

0 to 40% by weight of plasticizer (E), preferably 10 to 35% by weight

Total of polymeric binder (D) and plasticizer (E): 20 to 80% by weight, preferably 30 to 70% by weight

<Production of hologram recording medium>

The production of a hologram recording medium from the photosensitive resin composition of the present invention uses a known coating means such as a spin coater, a roll coater, a bar coater, or the like to form a liquid photosensitive resin composition, using a glass plate, a polycarbonate plate, or a polymethylmethacryl The method of apply | coating so that it may become a dry film thickness of 1-1000 micrometers on base materials, such as a rate plate and a polyester film, and if necessary, passes through a drying process and produces the hologram recording medium. At this time, you may form a protective layer as an oxygen barrier film on the photosensitive resin composition layer. As the protective layer, for example, a film or glass such as a polyolefin, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol or polyethylene terephthalate can be used. Moreover, when apply | coating a photosensitive liquid, you may dilute with a suitable solvent as needed, but in that case, after apply | coating on a board | substrate, drying is required.

<Light source and recording method for hologram recording>

The recording layer produced as described above can be subjected to interference exposure by a conventionally known method to form a volume phase hologram. For example, by two-beam interference fringe exposure by a conventional holographic exposure apparatus by laser light or light excellent in coherence (coherence) (for example, light having a wavelength of 300 to 1200 nm). An interference fringe is recorded therein. In this step, diffracted light by the recorded interference fringe is obtained, and it can be made into a hologram. Suitable light sources for the hologram recording material of the present invention include He-Ne laser (633 nm), Ar laser (515, 488 nm), YAG laser (532 nm), He-Cd laser (442 nm), blue DPSS laser (405 nm), and the like. It is available. In addition, after hologram recording by the laser or the like, unreacted ultraviolet rays are irradiated by a xenon lamp, a mercury lamp, a metal halide lamp or the like, or heat of about 60 ° C. is applied to the optical recording composition film, thereby remaining unreacted. Phase separation due to polymerization of some radically polymerizable compounds and mass transfer is promoted, and a hologram having better hologram characteristics is obtained.

Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. In addition, the symbol used in an Example is as follows.

DVB: divinylbenzene

DVB570: Mixed monomer having a component ratio of DVB and ethyl vinyl benzene of 57:43 (manufactured by Shinnitetsu Chemical Co., Ltd.)

S2EG: bis (2-methacryloylthioethyl) sulfide (manufactured by Sumitomo Seika Co., Ltd.),

TCP: tricresyl phosphate, (new Nippon Rika Corporation)

MS-200: methyl methacrylate-styrene (20:80) copolymer polymer,

MS-600: Methyl methacrylate-styrene (60:40) copolymer polymer.

In addition, evaluation of the hologram and the photosensitive resin composition in this Example was performed with the following method.

<Evaluation of Hologram>

* Evaluation of diffraction efficiency

The diffraction efficiency of the transmission hologram was calculated by the following equation using a value obtained by reading a diffracted light by a linearly polarized He-Ne laser (632.8 nm) with an optical power meter.

Diffraction efficiency (%) = (diffraction light intensity / incident light intensity) x 100

* Evaluation of environmental resistance

Change of diffraction efficiency and transparency 1 month after storage (storage at 60 ° C) (○: no change, △: slight change, ×: change)

* Volume shrinkage rate of photosensitive resin composition

The cure shrinkage rate of the photosensitive resin composition can be calculated by the following formula by measuring the density of the resin composition before and after curing. In addition, the spot UV irradiation apparatus was used for the light source, and UV of 6 mV / cm <2> was irradiated under air with respect to the 50-micrometer-thick sample.

Curing Shrinkage (%) = (1-Liquid Density / Film Density) × 100

Synthesis Example 1

2282 ml of toluene solution (toluene 1806 ml, monomer concentration: 1.31 mol / ml, dielectric constant: 2.38) of 1.75 mol (258.9 ml) of divinylbenzene, 1.30 mol (186.3 ml) of ethylvinylbenzene, and 1-chloroethylbenzene (289.1 mmol) It was put into a 3000 ml flask and heated at 30 degreeC. Further, 21.7 ml of a 12.64 mmol toluene solution of SnCl ₄ (concentration: 0.584 mmol / ml) was added and reacted for 4 hours. After stopping the polymerization reaction with a small amount of methanol bubbled with nitrogen, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a soluble aromatic copolymer. The obtained copolymer was washed with methanol, filtered off, dried and weighed to obtain 171.62 g (yield: 42.9 wt%) of soluble aromatic copolymer. The polymerization activity was 3.39 (g polymer / mmol Sn · hr). Mw of the obtained copolymer was 6930, Mn was 1990, and Mw / Mn was 3.48.

Synthesis Example 2

1.51 mol (223.4 ml) of divinylbenzene, 0.71 mol (123.2 ml) of ethylvinylbenzene, 5.5 ml of dichloroethane solution (concentration: 0.73 mmol / ml) of 1-chloroethylbenzene (364.2 mmol) and dichloroethane (dielectric constant: 10.3 ) 3500 ml was added into a 5000 ml flask, and 63.3 ml of a 50.11 mmol dichloroethane solution of SnCl ₄ (concentration: 0.074 mmol / ml) was added at 70 ° C., and reacted for 3 hours. After stopping the polymerization reaction with a small amount of methanol bubbled with nitrogen, the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a soluble aromatic polymer. The obtained copolymer was washed with methanol, filtered off, dried and weighed to obtain 178.91 g (yield: 61.3 wt%) of soluble aromatic copolymer. The polymerization activity was 8.54 (g polymer / mmol Sn · hr). Mw of the obtained copolymer was 49700, Mn was 9730, and Mw / Mn was 5.1.

Example 1

The following component was mix | blended and the photosensitive resin composition solution for volume phase hologram recording was produced.

Dichloromethane: 50 g of copolymer obtained in Synthesis Example 1: 10 g, TCP: 15 g, MS-200: 20 g, S2EG: 15 g, 1-hydroxycyclohexylphenyl ketone (Irgacure184, manufactured by Chiba Specialty Chemicals Co., Ltd.): 0.1 g, 3-ethyl-5-[(3-ethyl-2 (3H) -benzothiazolylidene) ethylidene] -2-thioxo-4-oxazolidinone (NK-1473, Inc.) Hayashibara Seibutsu Kagaku Genkusho): 0.01 g was dissolved to obtain a photosensitive liquid.

This is applied to one surface of a glass substrate having a thickness of 50 mm x 50 mm and a thickness of 0.5 mm using a bar coater so as to have a dry film thickness of 50 µm, and in an inert oven of nitrogen atmosphere set at 50 ° C for 1 hour. It dried and the photosensitive plate for volume phase hologram recording was produced. As a protective film, a 38 µm PET film was laminated thereon to form an optical information recording medium.

Using the two-beam interference exposure method by 514.5 nm light of the argon ion laser, the obtained recording medium was made into the interference fringe of about 1000 spaces / mm, and this was incident from the PET side, and the volume phase hologram was recorded. Exposure of the transmissive hologram was carried out at an exposure dose of 10 to 100 mJ / cm 2 for 10 seconds to 100 seconds, with one light intensity on the photosensitive plate being 1 mW / cm 2. The obtained volume phase hologram had a diffraction efficiency of 82% at an exposure dose of 13 mJ / cm 2. In addition, the cure shrinkage rate of the resin composition was 0.5%.

Examples 2-6 and Comparative Examples 1-3

A photosensitive resin composition solution was prepared in the same manner as in Example 1 except that the compounding composition was as shown in Table 1, an optical information recording medium was obtained, a hologram was recorded, and evaluation was performed. The composition and evaluation results are summarized in Table 1. In Table 1, DVB oligomer (Mn = 2000) shows the copolymer obtained by the synthesis example 1, and DVB oligomer (Mn = 10000) shows the copolymer obtained by the synthesis example 2.

According to the present invention, by using the soluble polyfunctional vinyl aromatic copolymer in the photosensitive resin composition, the volume phase hologram recording material, the volume phase hologram recording medium, and the volume which are excellent in transparency as well as sensitivity, low curing shrinkage rate and transparency. It is possible to provide a phased hologram.

Claims (5)

A soluble aromatic copolymer (A) having a structural unit of a divinyl aromatic compound and a structural unit of a monovinyl aromatic compound and containing 10 mol% or more of the structural unit represented by the following formula (a1); An optical radical polymerizable compound (B) copolymerizable with a soluble aromatic copolymer (A); Photopolymerization initiator (C); And at least one of a polymer binder (D) and a plasticizer (E). The photosensitive resin composition comprising 5 to 60% by weight of a soluble aromatic copolymer (A). Photosensitive resin composition for.

(However, R ¹ represents an aromatic hydrocarbon group having 6 to 30 carbon atoms.) The photosensitive resin composition for volume phase hologram recording according to claim 1, wherein the number average molecular weight of the soluble aromatic copolymer (A) is 400 to 30000. An optical information recording medium for volume phase hologram recording, wherein the recording layer made of the photosensitive resin composition according to claim 1 is formed on one support or between two supports. A volume phase hologram obtained by recording an interference fringe formed from an energy ray having excellent coherent property on the optical information recording medium according to claim 3. A method of manufacturing a volume phase hologram, wherein an interference fringe formed from an energy ray having excellent coherent properties is subjected to exposure recording on a recording medium according to claim 3.