JP2008152170A - Composition for holographic recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composition for a holographic recording medium which can be applied into a uniform film thickness and easily formed into a holographic recording medium of high sensitivity without volume shrinkage even when the medium is exposed to light, and to provide a high-density holographic recording medium that can be manufactured by using the above composition, has a low error rate and can store a large capacity. <P>SOLUTION: The composition for the holographic recording medium contains: a fluorine-containing polymerizable substance having a (meth)acrylate group; a polymerizable substance containing no fluorine but having a (meth)acrylate group copolymerizable with the above substance by light; an alicyclic epoxy group-containing cationic polymerizable substance performing ring-opening polymerization by heat; and a non-polymerizable substance containing no fluorine, having a solubility parameter smaller than that of the polymerizable substance containing no fluorine and larger than that of the fluorine-containing substance. The holographic recording medium has a holographic recording layer formed by applying the above composition on a substrate and polymerizing the alicyclic epoxy group-containing cationic polymerizable substance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a composition used for producing a holographic recording medium for recording light interference fringes, light amplitude, or the amplitude and phase thereof, and a holographic recording medium produced using the composition.

  Records and reproduces the interference fringes obtained by overlaying the reflected and transmitted waves from the reflected object and the reference wave, and records and reproduces the distribution of the amplitude and phase of the wave disturbance on the surface. Holography can store a large capacity.

  As a recording medium used for this holography, a dry volume holographic recording medium capable of mass production is used.

As raw materials for this volume holographic recording medium, photopolymers, azobenzene-based or diarylethene-based photochromic materials, and photorefractive materials such as LiNbO ₃ or liquid crystals are known.

  Among them, a volume holographic recording medium made of a photopolymer is a recordable memory (WORM) that is excellent in industrial mass productivity and can be used for a hologram optical disk and a card. For example, in Patent Document 1, a polymer matrix having a three-dimensional cross-linking structure, a polymerizable monomer, and a tertiary amine compound are constituents, and the polymer matrix is present in a presence of the polymerizable monomer by a polymerization reaction different from the polymerization reaction of the polymerizable monomer. The volume hologram recording material formed is described.

  The recording capacity of the volume holographic recording medium can be further increased, a uniform thick film can be formed to obtain a high-sensitivity, high-quality, high-performance disk-shaped recording medium that can be preformatted, has a low error rate Therefore, there has been a demand for a composition for a holographic recording medium in which the volume shrinkage of the photopolymer when exposed is extremely small.

International Publication No. 2005/078532 Pamphlet

  The present invention was made to solve the above-mentioned problems, and can be applied to a uniform film thickness, and a composition for a holographic recording medium that can easily produce a high-sensitivity holographic recording medium having no volume shrinkage even when exposed, Another object of the present invention is to provide a high-performance high-density holographic recording medium that can be manufactured using the same, has a small error rate, and can store a large capacity.

  The composition for a holographic recording medium according to claim 1, which has been made to achieve the above object, comprises a fluorine-containing polymerizable substance having a (meth) acrylic ester group and a photopolymerization thereof. A fluorine-free polymerizable substance having a (meth) acrylic acid ester group, an alicyclic epoxy group-containing cationic polymerizable substance that undergoes ring-opening polymerization by heat, and a solubility parameter smaller than that of the fluorine-free polymerizable substance A fluorine-free non-polymerizable substance larger than the fluorine-containing polymerizable substance is contained.

  The composition for a holographic recording medium according to claim 2 is the composition according to claim 1, wherein 0.5 to 10 parts by weight of the fluorine-containing polymerizable substance, and 7 to 30 of the fluorine-free polymerizable substance. Part by weight, 30 to 70 parts by weight of the alicyclic epoxy group-containing cationic polymerizable substance, and 5 to 40 parts by weight of the non-polymerizable substance are included.

  The composition for a holographic recording medium according to claim 3 is the composition according to claim 1, wherein the fluorine substituent in the fluorine-containing polymerizable substance has 6 to 10 carbon atoms. .

The composition for a holographic recording medium according to claim 4 is the composition according to claim 1, wherein the fluorine-containing polymerizable substance has the following chemical formula (1):
^{_{CH 2 = CR 1 -CO-O}} -CH 2 - (CF 2) b -CH 2 -O-CO-CR 2 = CH 2 ··· (1)
(In the chemical formula (1), b is a number of 6 to 10, and R ¹ and R ² are the same or different and are represented by a hydrogen atom or a methyl group).

  The composition for a holographic recording medium according to claim 5 is the composition according to claim 1, wherein the fluorine-free polymerizable substance has a refractive index of 1.55 at a minimum. To do.

  The composition for a holographic recording medium according to claim 6 is the composition according to claim 1, wherein the alicyclic epoxy group-containing cationic polymerizable substance has a refractive index of 1.53 at the maximum. It is characterized by that.

  The composition for a holographic recording medium according to a seventh aspect is the composition according to the first aspect, wherein the non-polymerizable material has a refractive index of at most 1.52.

  The holographic recording medium according to claim 8, wherein the composition according to any one of claims 1 to 7 is applied onto a substrate, and the alicyclic epoxy group-containing cationic polymerizable substance thereof is polymerized to produce holographic recording. A layer is formed.

  The holographic recording method according to claim 9 is characterized in that the holographic recording medium according to claim 8 is irradiated with light to copolymerize the fluorine-containing polymerizable substance and the fluorine-free polymerizable substance. To do.

  A holographic recording method according to a tenth aspect is the holographic recording method according to the ninth aspect, wherein the light is laser light.

  The composition for a holographic recording medium of the present invention can be easily prepared and can be applied to a substrate with a uniform film thickness. A holographic recording medium obtained by applying this composition to a substrate and thermosetting it can be exposed with high sensitivity with a coherent laser beam or the like, and the volumetric shrinkage caused thereby is extremely small. Therefore, this holographic recording medium has high sensitivity, a small error rate, a high density, and a large capacity. Furthermore, since the structure can be simplified, productivity is high.

  According to the storage method using this holographic recording medium, a large capacity can be recorded and reproduced with almost no error.

  Examples of the present invention will be described in detail below, but the scope of the present invention is not limited to these examples.

  Examples of preferred embodiments of the holographic recording medium composition include a fluorine-containing polymerizable material having a (meth) acrylate group, a fluorine-free polymerizable material having a (meth) acrylate group, and an alicyclic epoxy group-containing material. Mix the cationically polymerizable substance, the plasticizer that is a fluorine-free non-polymerizable substance whose solubility parameter is smaller than that of the fluorine-free polymerizable substance and larger than that of the fluorine-containing polymerizable substance, and, if necessary, a solvent and a polymerization catalyst. To be prepared.

（化学式（２）中、ｎ１及びｎ２は同一又は異なり０〜１の数）で表わされるパーフルオロアダマンチル含有基から選ばれるフッ素置換基含有基を有している。 The fluorine-containing polymerizable substance is, for example,-(CH ₂ ) _a1- (CF ₂ ) _b- (CH ₂ ) _a2-
(However, a1 and a2 are the same or different and are numbers 1-2, b = 6-10),
_{- (CH 2) d1 - (} CF 2) e -C [- (CF 2) f -F] [- (CF 2) g -F] - (CH 2) d2 -
(However, d1 and d2 are the same or different and are 1-2, e = 1 to 9, f = 0 to 8, g = 1 to 9, and e + f + g = 6 to 10),
-(CH ₂ ) _{h 1-} (CF ₂ ) _i -(-O-C _j F _2j ) _k -O- (CF ₂ ) _m- (CH ₂ ) _{h 2-}
(However, h1 and h2 are the same or different and are 1-2, i = 1-3, j = 1-4, k = 1-9, m = 0-3, and i + j × k + m = 6-10. number),
And the following chemical formula (2)

(In the chemical formula (2), n1 and n2 are the same or different and have a number of 0 to 1) and have a fluorine substituent-containing group selected from perfluoroadamantyl-containing groups.

For example, the fluorine-containing polymerizable substance is a compound having an ester group of (meth) acrylic acid and a diol containing a fluorine substituent having 6 to 10 carbon atoms, specifically, HO— (CH ₂ ) _a1 — ( CF ₂ ) _b — (CH ₂ ) _a1 —OH (where a1, a2 and b are the same as above) and (meth) acrylic acid, more specifically 2,2,3,3,4 , 4,5,5,6,6-decafluoroheptanediol, 2,2,3,3,4,4,5,5,6,6,7,7-dodecafluorooctanediol, 2,2,3 , 3,4,4,5,5,6,6,7,7,8,8-tetradecafluorononanediol, or 2,2,3,3,4,4,5,5,6,6, Examples include esters of 7,7,8,8,9,9-heptadecafluorodecanediol and (meth) acrylic acid.

Fluorine-containing polymerizable _{substance, HO- (CH 2) d1 -} (CF 2) e -C [- (CF 2) f -F] [- (CF 2) g -F] - (CH 2) d2 -OH (Where d1, d2, e, f and g are the same as above) and an ester of (meth) acrylic acid, such as 2-fluoro-2-perfluorooctyl-1,3-propanediol, 2-fluoro-2 Examples include esters of -perfluoroisooctyl-1,3-propanediol or 2-fluoro-2-perfluoro (4-ethyl-hexyl) -2-hydroxymethyl-1-methanol with (meth) acrylic acid It is done.

Fluorine-containing polymerizable _{substance, HO- (CH 2) h1 -} (CF 2) i - (- O-C j F 2j) k -O- (CF 2) m - (CH 2) h2 -OH ( provided that h1, h2, i, j, k and m are the same as above) and an ester of (meth) acrylic acid, for example, 2,2,4,4,5,5,7,7-octafluorotriethylene glycol, 2 , 2,4,4,5,5,7,7,8,8,10,10-dodecafluorotetraethylene glycol, 2,4,4,5,7,7-hexafluoro-2,5,8- Also included are esters of tri (trifluoromethyl) triethylene glycol and (meth) acrylic acid.

（但し、ｎ１、ｎ２は前記に同じ）で表わされるパーフルオロアダマンチル含有基ジオールと（メタ）アクリル酸とのエステルも挙げられる。 The fluorine-containing polymerizable substance has the following chemical formula (3)

(However, n1 and n2 are the same as above.) An ester of a perfluoroadamantyl-containing group diol represented by (meth) acrylic acid is also included.

Among these, the fluorine-containing polymerizable substance has the following chemical formula (1)
^{_{CH 2 = CR 1 -CO-O}} -CH 2 - (CF 2) b -CH 2 -O-CO-CR 2 = CH 2 ··· (1)
(In the chemical formula (1), b is preferably a number of 6 to 10, and R ¹ and R ² are the same or different and are each a hydrogen atom or a methyl group).

The fluorine-free polymerizable substance is, for example, a compound having an ester group of (meth) acrylic acid and a diol, specifically, the following chemical formula (4)

(In the chemical formula (4), q and p are the same or different and are 0 to 6 and q + p = 2 to 6, and R ³ and R ⁴ are the same or different and are a hydrogen atom or a methyl group). It is more preferable that q + p is 5. This can be used alone or in combination with a general monofunctional (meth) acrylate, monofunctional vinyl compound, or polyfunctional (meth) acrylate. Examples of the monofunctional (meth) acrylate include phenoxy (meth) acrylate, phenylphenoxy (meth) acrylate, phenoxyethyl (meth) acrylate, and phenylphenoxyethyl (meth) acrylate. Examples of the monofunctional vinyl compound include N-vinylacetamide and N-vinylformamide. Furthermore, examples of the polyfunctional (meth) acrylate include trimethylolpropane, its alkylene oxide adduct and (meth) acrylic acid adduct, and di (meth) acrylate of alkylene glycol including neopentyl glycol.

  In addition, the alicyclic epoxy group-containing cationic polymerizable material is a compound containing an epoxy group-containing cycloalkyl group, for example, even if it is a polyfunctional epoxy compound having a plurality of epoxy groups, a monofunctional compound having one epoxy group. Epoxy compounds may be used.

（但し、化学式（５）中、ｒが０〜１０の数）が挙げられる。ｒが０のものとｒが１〜１０のものとの混合物、例えば当量混合物であってもよい。 The alicyclic epoxy group-containing cationic polymerizable substance is a polyfunctional epoxy compound, specifically, the following chemical formula (5)

(However, in chemical formula (5), r is a number from 0 to 10). A mixture of one where r is 0 and one where r is 1 to 10, for example, an equivalent mixture may be used.

  Another alicyclic epoxy group-containing cationic polymerizable material is, for example,

（化学式（１５）中、ｓは１以上の数）

(In the chemical formula (15), s is a number of 1 or more)

（化学式（１６）中、ｔ，ｕは０以上の数）

(In the chemical formula (16), t and u are 0 or more numbers)

Is mentioned. More specifically, UVR-6110, 6199 (both manufactured by Dow Chemical Co., Ltd .: trade name), Celoxide 2083, 2085, Eporide GT-302, GT-303, GT-401, GT-402. (Both manufactured by Daicel Chemical Industries, Ltd .: trade name).

  In addition, the alicyclic epoxy group-containing cationic polymerizable material is a monofunctional epoxy compound, specifically,

（化学式（２２）中、ｖは１以上の数）
が挙げられる。

(In chemical formula (22), v is a number of 1 or more)
Is mentioned.

Further, the non-polymerizable substance is, for example, the following chemical formula (23)
_{H- (CH 2) w1 -O-} CO- (CH 2) x -CO-O- (CH 2) w2 -H ··· (23)
(In the chemical formula (23), w1 and w2 are the same or different and are preferably 1 to 8 and x is a number of 2 to 18), preferably dimethyl adipate, dibutyl adipate, dimethyl sebacate, Examples include diethyl sebacate, dibutyl sebacate, and dinonyl phthalate, but dibutyl sebacate is more preferable.

The solubility parameter is an amount δ derived from the theory of a regular solution and defined by δ = (ΔH / V) ^1/2 where ΔH is the heat of molar evaporation and V is the molar volume of a non-polymerizable substance that is a liquid. It is.

  In the above formula, a to x may be integers within the above range.

  The holographic recording medium is obtained by applying this composition on a substrate and applying it to cationic polymerization of an alicyclic epoxy group-containing cationic polymerizable substance to cure, thereby forming a holographic recording layer. . In this case, examples of the thermosetting agent include aromatic onium salts such as Sun-Aid SI-60L, 80L, and 110L (all manufactured by Sanshin Chemical Industry Co., Ltd .: trade name).

  Examples of the photopolymerization initiator at the time of recording include benzophenones, benzoin alkyl ketals, and CGI-784 (trade name, manufactured by Ciba Geigy) known as a general name titanocene. These are used alone or as sensitizing dyes. It can be used in combination.

  The holographic recording medium is a transmissive disc-shaped medium, for example, a holographic recording layer formed on a glass base layer having an antireflection film on the bottom, and a glass layer, a servo substrate layer, an antireflection film layer on the glass substrate layer. The thing laminated | stacked in order is mentioned. The holographic recording medium is a reflective disk-shaped medium, for example, a polycarbonate base layer, an aluminum layer, a transparent resin film layer, a wavelength selective film layer, a glass layer, a holographic recording layer, a glass layer, and an antireflection film layer in this order. The thing laminated | stacked is also mentioned. The holographic recording medium may be in the form of a coupon.

  When this holographic recording medium is irradiated with laser light, which is coherent light, the fluorine-containing polymerizable substance and the fluorine-free polymerizable substance are polymerized. As a result, the refractive index is changed and holographic recording can be performed. The shrinkage at that time is almost zero.

  The mechanism by which the holographic recording medium does not shrink will be described with reference to FIG. 1 schematically showing the components of the composition for the holographic recording medium.

  The composition for a holographic recording medium coated on a substrate is composed of a fluorine-containing polymerizable substance 1, a fluorine-free polymerizable substance 2, and an alicyclic epoxy group-containing cationic polymerizable substance as shown in FIG. The substance 3 and the non-polymerizable substance 4 are in a randomly mixed state.

  When it is coated on a substrate (not shown) and heated, the alicyclic epoxy group-containing cationic polymerizable substance 3 undergoes ring-opening polymerization as shown in FIG. Form. The fluorine-free polymerizable substance 2 having an sp value close to the solubility parameter (sp value) of the matrix 5 is included in the molecules of the matrix 5 in the gel, thereby forming an unrecorded holographic recording medium.

  When it is irradiated with laser light, the fluorine-free polymerizable material 2 is extracted from the molecules of the matrix 5 in the minute space of the irradiated region, as shown in FIG. Polymerizes to form copolymer 6. As a result, the volume of the copolymer 6 contracts slightly more than the volume of the fluorine-containing polymerizable substance 1 and the fluorine-free polymerizable substance 2.

  On the other hand, the non-polymerizable substance 4 immediately enters the gap in the molecule of the matrix 5 formed by drawing out the fluorine-free polymerizable substance 2 and is included. Since the non-polymerizable substance 4 has a slightly larger sp value than the fluorine-free polymerizable substance 2, it causes a steric repulsion between the molecules of the matrix 5 and the molecules of the non-polymerizable substance 4. The matrix 5 containing the non-polymerizable material 4 is expanded. Furthermore, the molecules of the copolymer 6 and the molecules of the copolymer 6 and the non-polymerizable substance 4 are electrostatically repelled by fluorine atoms in the copolymer 6. As a result, the volume of the matrix 5 containing the non-polymerizable material 4 as shown in FIG. 3C is more than the volume of the matrix 5 containing the fluorine-free polymerizable material 2 as shown in FIG. Is slightly larger. As a result, the gel expands slightly. As a result, the shrinkage due to the formation of the copolymer 6 and the expansion due to the formation of the gel cancel each other. As a result, the shrinkage rate of the entire system becomes almost zero.

  Examples of the present invention in which a composition for a holographic recording medium is prepared, a holographic recording medium is produced using the composition, and its physical properties and functionality are evaluated are shown below.

（化学式（２５）中、ｐ及びｑは、ｐ＋ｑが５となる数）で表わされ、屈折率が１．５８３２で溶解パラメータが１０．６２であるフッ素不含有重合性物質の１６．１５重量部と、
下記化学式（５）

（化学式（５）中、ｒが０〜１０である化合物の混合物）で表わされ、屈折率が１．４８７５で溶解パラメータが１０．１６である脂環式エポキシ基含有カチオン重合性物質の５３重量部と、
下記化学式（２６）
n-Ｃ₄Ｈ₉-Ｏ-ＣＯ-(ＣＨ₂)₈-ＣＯ-Ｏ-n-Ｃ₄Ｈ₉ ・・・（２６）
で表わされ、屈折率が１．４３９３で溶解パラメータが９．１２である非重合性物質の３０重量部と、さらに、熱硬化剤としてサンエイドＳＩ−６０Ｌ（三新化学工業社製：商品名）の５重量部、及び光重合開始剤としてＩｒｇａｃｕｒｅ＃７８４（チバ・スペシャルティ・ケミカルズ社製：商品名）の３重量部とを、均一に溶解させてホログラフィ記録媒体用組成物を調製した。 (Example 1)
The following chemical formula (24)
_{CH 2 = CH-CO-O} -CH 2 - (CF 2) 8 - (CH 2) -O-CO-CH = CH 2 ··· (24)
0.85 parts by weight of a fluorine-containing polymerizable material represented by the following formula: refractive index 1.3703 and sp value 8.31;
The following chemical formula (25)

(In the chemical formula (25), p and q are the numbers at which p + q is 5), and the refractive index is 1.5832 and the solubility parameter is 10.62. And
The following chemical formula (5)

53 of the alicyclic epoxy group-containing cationically polymerizable substance represented by (a mixture of compounds in which r is 0 to 10 in the chemical formula (5)), having a refractive index of 1.4875 and a solubility parameter of 10.16. Parts by weight,
The following chemical formula (26)
_{n-C 4 H 9 -O-} CO- (CH 2) 8 -CO-O-n-C 4 H 9 ··· (26)
And 30 parts by weight of a non-polymerizable material having a refractive index of 1.4393 and a solubility parameter of 9.12, and a sun-aid SI-60L (manufactured by Sanshin Chemical Industry Co., Ltd .: trade name) as a thermosetting agent ) And 3 parts by weight of Irgacure # 784 (manufactured by Ciba Specialty Chemicals: trade name) as a photopolymerization initiator were uniformly dissolved to prepare a composition for a holographic recording medium.

  In order to adapt to the measurement method of the gas pycnometer (made by Shimadzu Corporation: trade name) which is a gas density meter used to measure the shrinkage when the composition is cured, the holographic recording medium is made into a coupon shape. Instead, the composition was placed in a screw tube and sealed with a cap.

  It was heated at 90 ° C. for 2 hours to heat cure the alicyclic epoxy group-containing cationic polymerizable substance. The density at this time was measured with a gas density meter.

Next, instead of laser light irradiation, which is a local irradiation in which the difference in shrinkage rate is difficult to understand, irradiation was performed with a high-energy mercury lamp with good energy efficiency, which is an overall irradiation in which the difference in refractive index is easy to understand. The fluorine-containing polymerizable substance and the fluorine-free polymerizable substance were copolymerized by irradiation with ultraviolet rays of 2000 mJ / cm ^{2 from} a 1 kW high-pressure mercury lamp. The density at this time was measured with a gas density meter.

From the density before and after irradiation, the following formula shrinkage rate (%) = 100 × (density after irradiation−density before irradiation) / density before irradiation corresponds to holographic recording corresponding to light irradiation such as laser light. The shrinkage rate during the copolymerization of the fluorine-containing polymerizable substance and the fluorine-free polymerizable substance was calculated. The results are shown in Table 1.

(Comparative Examples 1-4)
Comparative Example 1 was carried out in the same manner as Example 1 except that no fluorine-containing polymerizable substance was used, and Comparative Example 2 was carried out except that a fluorine-containing polymerizable substance and a non-polymerizable substance were not used. In the same manner as in Example 1, preparation and shrinkage ratio were calculated. Comparative Example 3 uses a fluorine-containing polymerizable substance or a fluorine-free polymerizable substance, an alicyclic epoxy group-containing cationic polymerizable substance, a non-polymerizable substance, and a thermosetting agent as a photopolymerization initiator. Preparation and shrinkage ratio were calculated in the same manner as in Example 1 except that 3 parts by weight of Irgacure # 784 was used. The results are shown in Table 1.

  The composition for the holographic recording medium of Example 1 was appropriately selected from a copolymer of a fluorine-containing polymerizable substance and a fluorine-free polymerizable substance, an alicyclic epoxy group-containing cationic polymerizable substance, and a non-polymerizable substance. Therefore, the shrinkage rate when irradiated with light was 0%. On the other hand, the compositions lacking any of them as in Comparative Examples 1 to 4 had a shrinkage rate of 0.2 to 10.1% when irradiated with light.

  Next, an example in which a holographic recording medium is prototyped using the composition of Example 1 will be described.

  A heating apparatus in which the composition of Example 1 is sandwiched between non-reflective coatings using a 1.2 mm thick glass substrate having two antireflective coatings and the temperature is controlled while maintaining a 400 μm gap. A coupon-shaped holographic recording medium was prototyped by thermosetting at 90 ° C. for 2 hours.

  Further, this composition is sandwiched between a substrate having a transparent format signal surface and a glass disk having an antireflection film, and a surface not provided with the antireflection film, and maintaining a 400 μm gap in a temperature-controlled heating apparatus. A transmission type disk-shaped holographic recording medium was manufactured by thermosetting at 90 ° C. for 2 hours. The recording medium has a diameter of 120 mm and an inner diameter of 15 mm.

  Further, this composition is sandwiched between a surface having no antireflection film using a glass disk having an aluminum reflection film on the format signal surface and a wavelength selective film on the transparent layer and a glass disk having an antireflection film, and has a thickness of 400 μm. A reflective disk-shaped holographic recording medium was prototyped by thermosetting at 90 ° C. for 2 hours in a heating apparatus in which the gap was maintained and the temperature was controlled. The recording medium has a diameter of 120 mm and an inner diameter of 15 mm.

  This holographic recording medium was further evaluated for physical properties and performance.

(1. Measurement of sensitivity and cumulative interference fringe intensity of holographic recording medium)
The sensitivity of the holographic recording medium with respect to the cumulative exposure and the dynamic range called cumulative interference fringe intensity (M number: #M) were measured with a plane wave tester. The result is shown in FIG. As is clear from FIG. 2, the maximum sensitivity was 8 cm / mJ, and M # was 13.

(2. Evaluation of recording performance of holographic recording media by collinear optical system)
Page data recording / reproduction of a holographic recording medium (coupon shape: recording layer thickness 400 μm) was performed using a collinear hologram evaluation system (reflection type) using a pulsed laser light source.

  130 holograms were recorded and reproduced by collinear shift multiplexing. FIG. 3 shows a change in error rate at the time of page data recording / reproduction of 130 holograms in a row at a shift interval of 10 μm using a coupon-shaped holographic recording medium. As is apparent from FIG. 3, the error rate was 5% or less over the entire area of 130 hologram recording / reproduction, and good recording / reproduction was performed.

(3. Evaluation of recording performance of disc-shaped holographic recording medium)
The transmission type holographic recording medium and the reflection type holographic recording medium were evaluated. With respect to the transmission type holographic recording medium, 32 holograms were recorded and reproduced on the entire circumference of one track. The error rate is shown in FIG.

  With respect to the reflection type holographic recording medium, one hologram was recorded in each sector of 120 sectors / rotation, that is, 120 holograms were recorded and reproduced on the entire circumference of one track. The error rate is shown in FIG.

  Next, multiple measurements of the holographic recording medium were performed using a plane wave tester. The result is shown in FIG. As is apparent from FIG. 6, the Bragg angle detuning is almost 0 °. A value of 0 ° indicates that the shrinkage rate is 0.

  The composition for a holographic recording medium of the present invention is useful as a raw material for hologram memory and optical components, and as a hologram material. A holographic recording medium having a recording layer obtained by curing this composition with heat is useful as a large-capacity high-density optical recording medium. This recording method using a recording medium is useful for storing personal computer data externally and for storing and copying large-capacity programs and image data.

It is the schematic diagram which showed the process of carrying out holography recording with the holographic recording medium formed with the composition for holographic recording media to which this invention is applied.

It is a figure which shows the correlation between the amount of accumulated exposure, the sensitivity of a holography recording medium, and accumulated interference fringe intensity | strength about the holography recording medium to which this invention is applied.

It is a figure which shows the change of the error rate at the time of the page data recording / reproducing of a hologram about the holography recording medium to which this invention is applied.

It is a figure which shows an error rate about the transmission system disk shape holography recording medium to which this invention is applied.

It is a figure which shows an error rate about the reflection system disk shape holography recording medium to which this invention is applied.

It is a figure which shows the result of the plane wave hologram measurement of the holography recording medium to which this invention is applied.

Explanation of symbols

  1 is a fluorine-containing polymerizable material, 2 is a fluorine-free polymerizable material, 3 is an alicyclic epoxy group-containing cationic polymerizable material, 4 is a non-polymerizable material, 5 is a matrix, and 6 is a copolymer.

Claims (10)

  A fluorine-containing polymerizable substance having a (meth) acrylic acid ester group, a fluorine-free polymerizable substance having a (meth) acrylic acid ester group that is copolymerized with light, and an alicyclic epoxy group that is ring-opening polymerized by heat A holography characterized in that it contains a cation-containing polymerizable substance and a non-fluorine-containing non-polymerizable substance whose solubility parameter is smaller than that of the fluorine-free polymerizable substance and larger than that of the fluorine-containing polymerizable substance. Composition for recording medium.   0.5 to 10 parts by weight of the fluorine-containing polymerizable substance, 7 to 30 parts by weight of the fluorine-free polymerizable substance, 30 to 70 parts by weight of the alicyclic epoxy group-containing cationic polymerizable substance, and the non-polymerization The composition for a holographic recording medium according to claim 1, wherein 5 to 40 parts by weight of the active substance is contained.   The composition for a holographic recording medium according to claim 1, wherein the fluorine substituent in the fluorine-containing polymerizable substance has 6 to 10 carbon atoms. The fluorine-containing polymerizable substance has the following chemical formula (1)
^{_{CH 2 = CR 1 -CO-O}} -CH 2 - (CF 2) b -CH 2 -O-CO-CR 2 = CH 2 ··· (1)
^{2. The} composition for a holographic recording medium according to claim 1, wherein b is a number of 6 to 10, and R ¹ and R ² are the same or different and are a hydrogen atom or a methyl group in the chemical formula (1). .   2. The composition for a holographic recording medium according to claim 1, wherein the fluorine-free polymerizable material has a refractive index of at least 1.55.   The composition for a holographic recording medium according to claim 1, wherein the alicyclic epoxy group-containing cationic polymerizable substance has a refractive index of 1.53 at the maximum.   The holographic recording medium composition according to claim 1, wherein the non-polymerizable substance has a refractive index of 1.52 at the maximum.   A composition according to any one of claims 1 to 7 is applied on a substrate, and the alicyclic epoxy group-containing cationic polymerizable material is polymerized to form a holographic recording layer. Holographic recording medium.   9. A holographic recording method comprising: irradiating the holographic recording medium according to claim 8 with light to copolymerize the fluorine-containing polymerizable substance and the fluorine-free polymerizable substance.   The holographic recording method according to claim 9, wherein the light is laser light.

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