JP2008291135A - Hologram recording medium substrate and hologram recording medium - Google Patents

Abstract

Provided are a hologram recording medium substrate and a hologram recording medium formed from a polycarbonate resin composition having both low birefringence, high rigidity, low moisture permeability, and low oxygen permeability.
A hologram comprising a light transmissive substrate and a substrate, a recording layer comprising a three-dimensional cross-linked polymer matrix formed between the substrate and the substrate, a radical polymerizable compound and a photo radical polymerization initiator. In the recording medium, the light-transmitting substrate 1 and the substrate 2 include a cyclohexyl group-containing carbonate structural unit [A] and a single bond, an alkylene group having 1 to 15 carbon atoms, or an alkylene group having an aromatic group having 1 to 20 carbon atoms. A higher fatty acid ester, phosphorus, and a polycarbonate resin comprising a carbonate structural unit having a group having a group in which two or more substituted or unsubstituted phenyl groups bonded by an oxygen atom are bonded, and [A] is 80 to 100 mol% A hologram recording medium, which is a substrate made of a resin composition to which a system stabilizer is added.
[Selection figure] None

Description

  The present invention is a hologram recording medium substrate formed from a polycarbonate resin composition having both low birefringence, high rigidity, low oxygen permeability, and low moisture permeability, and multiple recording properties composed of the hologram recording medium substrate, The present invention relates to a hologram recording medium having low shrinkage and excellent shelf life.

  Hologram recording media that perform recording and reproduction using light are one of the optical recording technologies that can realize large capacity and high-speed transfer compared to magneto-optical recording media and phase change optical recording media. In particular, a recording method using a volume hologram is promising as a high-density recording medium because multiple recording is possible.

  When the information light and the reference light provided with information as a two-dimensional image are irradiated, interference fringes composed of a dark part and a bright part are formed in the recording layer of the volume hologram recording medium. In the bright part where the light is strongly irradiated, the photopolymerization reaction of the radical polymerizable monomer proceeds, and the radical polymerizable monomer diffuses from the dark part where the light is weakly irradiated toward the bright part, resulting in a concentration gradient. That is, in the volume hologram recording medium, the refractive index difference accompanying the concentration difference of the radical polymerizable compound is held as recording information.

  In a volume hologram recording medium, increasing the thickness of the recording layer is important. In general, the thicker the hologram, the stricter the incident light angle condition for diffracting, and the diffracted light disappears only by shifting it slightly from the black condition. Using this angle selectivity, it is possible to form and read out a plurality of holograms in the same volume. That is, if the angle selectivity can be improved by increasing the film thickness of the recording layer, the multiplicity increases and the recording capacity can be increased.

  As a recording layer of this volume hologram recording medium, a configuration having a three-dimensional crosslinked polymer matrix in addition to a radical polymerizable compound and a photo radical polymerization initiator is generally known (for example, Patent Document 1). The three-dimensional cross-linked polymer matrix has a function of suppressing excessive movement of the radical polymerizable compound and suppressing volume change in a portion corresponding to a bright portion and a portion corresponding to a dark portion in the recording layer. Examples of the material of the three-dimensional crosslinked polymer matrix include a reaction cured product derived from an epoxy compound and a cationic polymerizable monomer (for example, see Patent Document 2).

  A volume hologram recording medium is composed of a hologram recording layer, a light-transmitting first layer sandwiching the recording layer, and a second layer as a support, and a glass substrate is generally used for the light-transmitting layer and the support layer. I came. However, taking into consideration mass productivity, cost, etc., it is anxious to use a plastic substrate formed by various processing methods including injection molding. In this case, since the transparency, mechanical properties, and dimensional stability are excellent, a polycarbonate resin obtained by reacting a carbonate precursor with 2,2-bis (4-hydroxyphenyl) propane (hereinafter referred to as bisphenol A). (Hereinafter referred to as PC-A) and amorphous polyolefins have been studied.

  In the volume hologram recording medium, since the multiple recording for recording the hologram in the same volume is performed by changing the incident light angle of the information light, the angle dependency of the incident light on the substrate material becomes important. Usually, when a laser beam is transmitted through a light-transmitting layer made of PC-A, birefringence due to molecular orientation, residual stress, and the like generated during injection molding, which is a substrate forming process, is generated. Furthermore, in the case of PC-A, it has angle dependence of birefringence, and the birefringence increases as the incident angle increases. That is, it can be said that this is a fatal defect for a volume hologram medium in which information is recorded and / or reproduced by transmitting laser light through the light transmission layer.

  Further, the above-mentioned radical polymerizable compound is used for the recording layer, and the recording layer shrinks due to the photopolymerization reaction after the laser light irradiation. This shrinkage increases as the recording layer becomes thicker, and the entire hologram recording medium is deformed. When the hologram is reproduced, the recorded hologram is displaced due to contraction and cannot be reproduced. In particular, when a substrate material that has a low rigidity (for example, amorphous polyolefin) is used as a support, it becomes a fatal defect. Further, the substrate using PC-A is insufficient.

Since the recording layer records information using a radical polymerization reaction, the reactivity of the recording material decreases due to the influence of oxygen that inhibits the radical polymerization reaction. In particular, a substrate material having a low oxygen permeability coefficient is required because it is affected by oxygen transmitted from the substrate material.
Furthermore, since the recording layer used for the volume hologram medium is deteriorated by moisture absorption, the recording performance as the recording medium is lowered. In particular, since deterioration occurs due to moisture permeated from the substrate material, the shelf life of the recording medium can be improved by using a substrate having low moisture permeability.

  As a substrate material for an optical disk with reduced birefringence, polycarbonate resin derived from 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane is known, but a recordable or rewritable DVD (Digital Versatile) is known. It is applied to a system that collects a single laser beam (such as Disk) and records it on an organic or inorganic recording film or phase change film by a thermal factor, and records by interfering with two lasers specific to a hologram recording medium. The method to do is not considered. Further, the above polycarbonate resin is known as a substrate material for optical disks with reduced oxygen permeability and moisture permeability, but it is applied to a limited reproduction type optical medium in which a dye layer that changes color by oxygen is laminated on a recording layer. Therefore, the hologram recording medium is not considered. (For example, Patent Documents 3, 4, 5, and 6)

For these reasons, there is no case where a polycarbonate resin having both birefringence, high rigidity, low oxygen permeability, and low moisture permeability is applied to a volume hologram recording medium.
As described above, a material having both low birefringence, high rigidity, low oxygen permeability, and low moisture permeability is required as a light transmission layer and / or a support for use in a volume hologram recording medium.

JP-A-11-161137 Japanese Patent Laid-Open No. 2005-107312 Special Table 2002-539323 Special table 2003-535948 gazette JP 2005-538483 A Special table 2007-504580 gazette

  An object of the present invention is to provide a hologram recording medium substrate and a hologram recording medium formed from a polycarbonate resin composition having both low birefringence, high rigidity, low oxygen permeability, and low moisture permeability.

（式中、Ｒ^１〜Ｒ^２は夫々独立して水素原子、芳香族基を含んでもよい炭素原子数１〜９の炭化水素基、またはハロゲン原子である。）
（Ｂ）下記式［２］

（式中、Ｒ^３〜Ｒ^６は夫々独立して水素原子、炭素原子数１〜９の芳香族基を含んでもよいアルキル基、炭素原子数６〜１０のアリール基、または炭素原子数１〜６のアルコキシ基を表す。Ｗは単結合、炭素原子数１〜１５のアルキレン基、または炭素原子数１〜２０の芳香族基を含んでもよいアルキレン基、または酸素原子を表す。）
で表される構成単位［Ｂ］とから構成され、全構成単位における構成単位（Ａ）の割合が８０〜１００モル％からなるポリカーボネート樹脂に対して
（Ｃ）下記式[３]

（式中、Ｒ^７は炭素数１〜２２の（ｔ＋ｕ）価の脂肪族炭化水素基を表し、Ｒ^８は炭素数１２〜２２のアルキル基を表す。ｔは０または正の整数を表し、ｕは正の整数を表し、且つ（ｔ＋ｕ）は１〜６の整数を表す。）
で表される一価及び／または多価アルコールの高級脂肪酸エステル０.０１〜１重量％、および
（Ｄ）燐系安定剤０．０００１〜０.５重量％
を含有するポリカーボネート樹脂組成物からなる基板であることを特徴とするホログラム記録媒体及びホログラム記録媒体用基板である。該ポリカーボネート樹脂組成物から形成された基板は、低複屈折、高剛性、低透湿性、且つ低酸素透過性を示す。そして、該基板より構成されるホログラム記録媒体は、多重記録性能に優れ、且つ記録時の記録層内で生じる光重合反応における収縮変形を抑制し、且つ媒体のシェルフライフを向上することができることを見出し、本発明に到達した。 In order to achieve the above object, the present invention has made extensive studies on a hologram recording medium substrate and a hologram recording medium. That is, the information light provided with information as a two-dimensional image and the reference light that can interfere with the information light are superimposed inside the recording medium, information is recorded as an interference pattern, and the reference light is irradiated during reproduction. In the recording / reproducing system using holography for reproducing the image information by diffracting the light with the interference fringes, the light transmissive substrate 1 and the substrate 2 as the support, and 3 formed between the substrate 1 and the substrate 2 are formed. In a hologram recording medium composed of a recording layer containing a dimensionally cross-linked polymer matrix, a radical polymerizable compound and a photo radical polymerization initiator, the light transmissive substrate 1 and the support substrate 2 are represented by (A) the following formula [1]. The structural unit [A] and

(In the formula, R ^{1 and} R ² are each independently a hydrogen atom, a hydrocarbon group having 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom.)
(B) The following formula [2]

(Wherein R ^{3 to} R ⁶ are each independently a hydrogen atom, an alkyl group that may contain an aromatic group having 1 to 9 carbon atoms, an aryl group having 6 to 10 carbon atoms, or 1 to 1 carbon atom) Represents an alkoxy group of 6. W represents a single bond, an alkylene group having 1 to 15 carbon atoms, an alkylene group which may contain an aromatic group having 1 to 20 carbon atoms, or an oxygen atom.)
(C) the following formula [3] with respect to the polycarbonate resin comprising the structural unit [B] represented by the formula (B):

(Wherein R ⁷ represents a (t + u) -valent aliphatic hydrocarbon group having 1 to 22 carbon atoms, R ⁸ represents an alkyl group having 12 to 22 carbon atoms, t represents 0 or a positive integer, u represents a positive integer, and (t + u) represents an integer of 1 to 6.)
Higher fatty acid esters of monohydric and / or polyhydric alcohols represented by 0.01 to 1% by weight, and (D) phosphorus stabilizers 0.0001 to 0.5% by weight
A hologram recording medium and a substrate for a hologram recording medium, characterized by being a substrate made of a polycarbonate resin composition containing A substrate formed from the polycarbonate resin composition exhibits low birefringence, high rigidity, low moisture permeability, and low oxygen permeability. The hologram recording medium composed of the substrate has excellent multiplex recording performance, can suppress shrinkage deformation in the photopolymerization reaction that occurs in the recording layer during recording, and can improve the shelf life of the medium. The headline, the present invention has been reached.

（式中、Ｒ^１〜Ｒ^２は夫々独立して水素原子、芳香族基を含んでもよい炭素原子数１〜９の炭化水素基、またはハロゲン原子である。）
（Ｂ）下記式［２］

（式中、Ｒ^３〜Ｒ^６は夫々独立して水素原子、炭素原子数１〜９の芳香族基を含んでもよいアルキル基、炭素原子数６〜１０のアリール基、または炭素原子数１〜６のアルコキシ基を表す。Ｗは単結合、炭素原子数１〜１５のアルキレン基、または炭素原子数１〜２０の芳香族基を含んでもよいアルキレン基、または酸素原子を表す。）
で表される構成単位［Ｂ］とから構成され、全構成単位における構成単位（Ａ）の割合が８０〜１００モル％からなるポリカーボネート樹脂から形成された基板である。 Hereinafter, the present invention will be described in detail.
<Hologram recording medium>
The hologram recording medium of the present invention comprises a light transmissive substrate 1 and a substrate 2 as a support, a three-dimensional cross-linked polymer matrix formed between the substrate 1 and the substrate 2, a radical polymerizable compound, and a photo radical polymerization initiator. The light transmissive substrate 1 and the support substrate 2 are (A) a structural unit [A] represented by the following formula [1] and

(In the formula, R ^{1 and} R ² are each independently a hydrogen atom, a hydrocarbon group having 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom.)
(B) The following formula [2]

(Wherein R ^{3 to} R ⁶ are each independently a hydrogen atom, an alkyl group that may contain an aromatic group having 1 to 9 carbon atoms, an aryl group having 6 to 10 carbon atoms, or 1 to 1 carbon atom) Represents an alkoxy group of 6. W represents a single bond, an alkylene group having 1 to 15 carbon atoms, an alkylene group which may contain an aromatic group having 1 to 20 carbon atoms, or an oxygen atom.)
Is a substrate formed from a polycarbonate resin in which the proportion of the structural unit (A) in all the structural units is 80 to 100 mol%.

  Usually, the recording medium substrate is produced by injection molding a polycarbonate resin. At this time, orientation birefringence caused by the orientation of molecular chains by the action of a strong shear force and stress birefringence caused by thermal stress are generated. Therefore, in order to reduce the stress birefringence caused by thermal stress as in the past, a sufficient birefringence reduction effect could not be obtained even when focusing only on the photoelastic coefficient of the dihydric phenol component constituting the polycarbonate. .

  When the present inventor examined birefringence in detail, in order to reduce the birefringence due to the orientation, the conventional PC- is used by using a structural unit containing a cyclohexyl group represented by the above formula [1]. It has been found that not only can the stress birefringence be lower than A, but also the orientation birefringence can be lowered. It has also been found that by using a structural unit containing a cyclohexyl group represented by the above formula [1], low gas permeability (oxygen, water vapor) can be expressed simultaneously. Further, it has been found that high rigidity is exhibited by introducing a substituent into the polymer side chain.

From the above knowledge, as the structural unit (A) represented by the above formula [1], compounds in which R ¹ and R ² are the same or different and are a hydrogen atom, an alkyl group having 1 to 9 carbon atoms, or a halogen group The compound which is a hydrogen atom or a C1-C3 alkyl group is more preferable. Specific examples of such preferable structural unit (A) include a structural unit having a carbonate bond derived from 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane.

As the structural unit (B) represented by the above formula [2], R ^{3 to} R ⁶ are each independently a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an aryl group having 6 to 10 carbon atoms, Alternatively, an alkoxy group having 1 to 6 carbon atoms is preferable, and W is preferably an alkylene group which may include a single bond, an alkylene group having 1 to 15 carbon atoms, or an aromatic group having 1 to 15 carbon atoms.

  Specific examples of the preferable structural unit (B) include 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) decane, 4,4 ′-(m-phenylenediene). Isopropylidene) diphenol, 1,1-bis (4-hydroxyphenyl) decane, 1,1-bis (3-methyl-4-hydroxyphenyl) decane, and 1,1-bis (2,3-dimethyl-4-) And a structural unit having a carbonate bond derived from (hydroxyphenyl) decane. Among these, as the structural unit (B), a structure having a carbonate bond derived from 1,1-bis (4-hydroxyphenyl) decane or 4,4 ′-(m-phenylenediisopropylidene) diphenol. Preferably it is a unit.

  Moreover, 80-100 mol% is preferable and, as for the ratio of the structural unit (A) in all the structural units, 90-100 mol% is the most preferable. In addition, even if it is 80-90 mol%, there is no problem on performance. The proportion of the structural unit (B) in all the structural units is preferably 20 to 0 mol%, and most preferably 10 to 0 mol%. Further, by using them as molding materials, optical molded products having extremely low birefringence, rigidity, moisture permeability coefficient, and oxygen transmission coefficient can be obtained, and the molded products are useful for hologram recording medium substrates. When the molar ratio of the structural unit (A) is less than 80 mol%, the photoelastic coefficient increases and the birefringence caused by the residual stress increases. Furthermore, since the content of the cyclohexyl group-containing dihydric phenol is reduced, moisture permeability and oxygen permeability are deteriorated, and the recording performance and shelf life of the hologram recording medium are deteriorated.

（式中、Ｒ^５は炭素数１〜２２の（ｔ＋ｕ）価の脂肪族炭化水素基を表し、Ｒ^６は炭素数１２〜２２のアルキル基を表す。ｔは０または正の整数を表し、ｕは正の整数を表し、且つ（ｔ＋ｕ）は１〜６の整数を表す。）
で表される、一価及び／または多価アルコールの高級脂肪酸エステルを含有する。 <Higher fatty acid ester of monohydric and / or polyhydric alcohol>
The polycarbonate resin composition used for the hologram recording medium substrate of the present invention,

(In the formula, R ⁵ represents a (t + u) -valent aliphatic hydrocarbon group having 1 to 22 carbon atoms, R ⁶ represents an alkyl group having 12 to 22 carbon atoms, t represents 0 or a positive integer, u represents a positive integer, and (t + u) represents an integer of 1 to 6.)
And higher fatty acid esters of monohydric and / or polyhydric alcohols.

  Such higher fatty acid esters of monohydric and / or polyhydric alcohols are partial esters or full esters of monohydric or polyhydric alcohols having 1 to 22 carbon atoms and saturated fatty acids having 12 to 22 carbon atoms. preferable.

  Specifically, stearic acid monoglyceride, stearic acid monosorbate, behenic acid monoglyceride, pentaerythritol monostearate, pentaerythritol tetrastearate, propylene glycol monostearate, stearyl stearate, palmityl palmitate, butyl stearate, Examples thereof include methyl laurate, isopropyl palmitate, and 2-ethylhexyl stearate.

  Among them, at least one selected from the group consisting of mono- or diesters of glycerin and stearic acid, mono- or diesters of glycerin and behenic acid, all esters of pentaerythritol and stearic acid, and all esters of pentaerythritol and behenic acid. In particular, stearic acid monoglyceride or pentaerythritol tetrastearate is preferably used. The content of the higher fatty acid ester of the monohydric and / or polyhydric alcohol is preferably 0.01 to 1% by weight, more preferably 0.015 to 0.5% by weight in the polycarbonate resin composition, and 0.02 to More preferred is 0.2% by weight.

  When the content is within this range, it is preferable that the mold release property is excellent and the mold release agent does not migrate and adhere to the metal surface. Further, the content of sodium metal contained in the higher fatty acid ester of the monohydric and / or polyhydric alcohol is preferably 1 ppm or less. When the content exceeds 1 ppm, the color of the manufactured disk substrate deteriorates, and the quality deteriorates due to an increase in white defects due to hydrolysis of the optical disk substrate made of the polycarbonate resin composition.

<Phosphorus stabilizer>
The polycarbonate resin composition used in the present invention contains at least one phosphorous stabilizer selected from the group consisting of phosphoric acid, phosphorous acid, phosphonic acid, phosphonous acid and esters thereof.

  The content of the phosphorus stabilizer is preferably 0.0001 to 0.5% by weight in the polycarbonate resin composition, more preferably 0.0005 to 0.2% by weight, and 0.001 to 0.1% by weight. Particularly preferred. By containing this phosphorus-based stabilizer, the thermal stability of such a polycarbonate resin composition is improved, and a decrease in molecular weight and a deterioration in hue during molding of an optical disk substrate made of the polycarbonate resin composition are prevented.

［式中、Ｒ^７〜Ｒ^２０は、それぞれ独立して、水素原子、メチル、エチル、プロピル、イソプロピル、ブチル、イソブチル、ｔｅｒｔ−ブチル、ペンチル、ヘキシル、ヘプチル、オクチル、ノニル、デシル、ドデシル、ヘキサデシル、オクタデシルなどの炭素原子数１〜２０のアルキル基、フェニル、トリル、ナフチルなどの炭素原子数６〜１５のアリール基またはベンジル、フェネチルなどの炭素原子数７〜１８のアラルキル基を表し、また１つの化合物中に２つのアルキル基が存在する場合は、その２つのアルキル基は互いに結合して環を形成していてもよい。］
よりなる群から選択された少なくとも１種以上である。 The phosphorus stabilizer is at least one selected from the group consisting of phosphoric acid, phosphorous acid, phosphonic acid, phosphonous acid and esters thereof, and preferably has the following general formula

[Wherein, R ^{7 to} R ²⁰ are each independently a hydrogen atom, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, hexadecyl. Represents an alkyl group having 1 to 20 carbon atoms such as octadecyl, an aryl group having 6 to 15 carbon atoms such as phenyl, tolyl and naphthyl, or an aralkyl group having 7 to 18 carbon atoms such as benzyl and phenethyl; When two alkyl groups are present in one compound, the two alkyl groups may be bonded to each other to form a ring. ]
And at least one selected from the group consisting of:

  Examples of the phosphorus stabilizer represented by the above formula [4] include triphenyl phosphite, trisnonylphenyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tridecyl phosphite, tri Octyl phosphite, trioctadecyl phosphite, didecyl monophenyl phosphite, dioctyl monophenyl phosphite, diisopropyl monophenyl phosphite, monobutyl diphenyl phosphite, monodecyl diphenyl phosphite, monooctyl diphenyl phosphite, etc. .

  Examples of the phosphorus stabilizer represented by the above formula [5] include tributyl phosphate, trimethyl phosphate, triphenyl phosphate, triethyl phosphate, diphenyl monoorthoxenyl phosphate, dibutyl phosphate, dioctyl phosphate, diisopropyl phosphate and the like.

  Examples of the phosphorus compound represented by the above formula [6] include tetrakis (2,4-di-tert-butylphenyl) -4,4-diphenylenephosphonite.

  Examples of the compound represented by the above formula [7] include dimethyl benzenephosphonate, diethyl benzenephosphonate, dipropyl benzenephosphonate and the like.

  Examples of the compound represented by the formula [8] include bis (2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphite, 2,2-methylenebis (4,6-di-tert-butyl). Phenyl) octyl phosphite, bis (nonylphenyl) pentaerythritol diphosphite, bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, and the like.

  Among these phosphorus stabilizers, tetrakis (2,4-di-t-butylphenyl) 4,4′-biphenylene-di-phosphonite, tetrakis (2,4-di-t-butylphenyl) 4,3 A mixture of '-biphenylene-di-phosphonite and tetrakis (2,4-di-t-butylphenyl) 3,3'-biphenylene-di-phosphonite, phosphoric acid, phosphorous acid, trimethyl phosphate, tris (2,4- Di-t-butylphenyl) phosphite and at least one compound selected from the group consisting of trisnonylphenyl phosphite are preferred, especially trisnonylphenyl phosphite and tris (2,4-di-tert-butylphenyl) phosphite Or tetrakis (2,4-di-tert-butylphenyl) -4,4-diphenyl Nhosuhonaito, it is preferably used.

<Antioxidant>
To the polycarbonate resin composition used in the present invention, an antioxidant generally known for the purpose of antioxidant can be added. Examples thereof include phenolic antioxidants, specifically, for example, triethylene glycol-bis (3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate), 1, 6-hexanediol-bis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), pentaerythritol-tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) ) Propionate), octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert- Butyl-4-hydroxybenzyl) benzene, N, N-hexamethylenebis (3,5-di-tert-butyl-4-hydroxy Rosinamide), 3,5-di-tert-butyl-4-hydroxy-benzylphosphonate-diethyl ester, tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 3,9-bis {1 , 1-dimethyl-2- [β- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] ethyl} -2,4,8,10-tetraoxaspiro (5,5) undecane, etc. Is mentioned. The range of preferable addition amount of these antioxidants is 0.0001 to 0.05% by weight in the polycarbonate resin composition.

<Production method of polycarbonate resin>
The reaction by the interfacial polymerization method is usually a reaction between a dihydric phenol and phosgene, and is reacted in the presence of an acid binder and an organic solvent. As the acid binder, for example, an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or an amine compound such as pyridine is used. As the organic solvent, for example, halogenated hydrocarbons such as methylene chloride and chlorobenzene are used. In order to accelerate the reaction, a catalyst such as a tertiary amine such as triethylamine, tetra-n-butylammonium bromide or tetra-n-butylphosphonium bromide, a quaternary ammonium compound or a quaternary phosphonium compound may be used. it can. At that time, the reaction temperature is usually 0 to 40 ° C., the reaction time is preferably about 10 minutes to 5 hours, and the pH during the reaction is preferably maintained at 9 or more.

（式中、Ａは水素原子または炭素原子数１〜９の直鎖または分岐のアルキル基あるいはフェニル置換アルキル基であり、ｒは１〜５、好ましくは１〜３の整数である。）
で表される単官能フェノール類を示すことができる。 In such a polymerization reaction, a terminal stopper is usually used. Monofunctional phenols can be used as such end terminators. Monofunctional phenols are commonly used as end terminators for molecular weight control, and the resulting polycarbonate resins are compared to those that do not because the ends are blocked by groups based on monofunctional phenols. Excellent thermal stability. Such monofunctional phenols are generally phenols or lower alkyl-substituted phenols having the following general formula [9]

(In the formula, A is a hydrogen atom, a linear or branched alkyl group having 1 to 9 carbon atoms or a phenyl-substituted alkyl group, and r is an integer of 1 to 5, preferably 1 to 3).
The monofunctional phenol represented by these can be shown.

  Specific examples of the monofunctional phenols include phenol, phenylphenol, p-tert-butylphenol, p-cumylphenol, tert-octylphenol and isooctylphenol.

  In addition, as other monofunctional phenols, phenols or benzoic acid chlorides having long chain alkyl groups or aliphatic ester groups as substituents, or long chain alkyl carboxylic acid chlorides can be used, When these are used to block the ends of the polycarbonate polymer, they not only function as end terminators or molecular weight regulators, but also improve the melt fluidity of the resin and facilitate the molding process, It is preferably used because it has the effect of lowering the physical properties of the resin, particularly the water absorption rate of the resin, and the effect of reducing the birefringence of the substrate.

  These end terminators are desirably introduced at at least 5 mol%, preferably at least 10 mol%, and more preferably introduced at 80 mol% or more of the ends of the obtained polycarbonate resin. Is done. Moreover, you may use a terminal terminator individually or in mixture of 2 or more types.

  The reaction by the melt polymerization method is typically a transesterification reaction between a dihydric phenol and a carbonate ester. An alcohol produced by mixing a dihydric phenol and a carbonate ester while heating them in the presence of an inert gas. Or it is performed by the method of distilling phenol. The reaction temperature varies depending on the boiling point of the alcohol or phenol produced, but is usually in the range of 120 to 350 ° C. In the latter stage of the reaction, the system is evacuated to about 1,300 Pa to 13 Pa (10 to 0.1 Torr) to facilitate the distillation of the alcohol or phenol produced. The reaction time is usually about 1 to 4 hours.

  Examples of the carbonate ester include esters such as an aryl group having 6 to 10 carbon atoms, an aralkyl group, or an alkyl group having 1 to 4 carbon atoms which may have a substituent. Specific examples include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, dimethyl carbonate, diethyl carbonate, and dibutyl carbonate. Is preferred.

A polymerization catalyst can be used to increase the polymerization rate. Examples of the polymerization catalyst include alkali metal and alkaline earth metal hydroxides such as sodium hydroxide and potassium hydroxide, boron and aluminum hydroxides, alkali metal salts, alkaline earth metal salts, and quaternary ammonium salts. Alkoxides of alkali metals and alkaline earth metals, organic acid salts of alkali metals and alkaline earth metals, zinc compounds, boron compounds, silicon compounds, germanium compounds, organic tin compounds, lead compounds, antimony compounds, manganese compounds, titanium compounds And catalysts usually used in esterification reactions and transesterification reactions of zirconium compounds and the like. A catalyst may be used independently and may be used in combination of 2 or more types. The amount of these polymerization catalysts used is preferably 1 × 10 ⁻⁹ to 1 × 10 ⁻⁵ equivalents, more preferably 1 × 10 ^{−8 to} 5 × 10 ⁻⁶ equivalents, per 1 mol of the raw material dihydric phenol. Selected by range.

  Further, in this polymerization reaction, for example, 2-chlorophenylphenyl carbonate, 2-methoxycarbonylphenylphenyl carbonate and 2-ethoxycarbonylphenylphenyl carbonate are added at the later stage or after completion of the polycondensation reaction in order to reduce the phenolic end groups. In particular, 2-methoxycarbonylphenyl phenyl carbonate is preferably used.

Further, in the melt transesterification method, it is preferable to use a deactivator that neutralizes the activity of the catalyst. The amount of the deactivator is preferably 0.5 to 50 mol with respect to 1 mol of the remaining catalyst. Further, it is used in a proportion of 0.01 to 500 ppm, more preferably 0.01 to 300 ppm, particularly preferably 0.01 to 100 ppm with respect to the aromatic polycarbonate resin after polymerization. Preferred examples of the deactivator include phosphonium salts such as tetrabutylphosphonium dodecylbenzenesulfonate and ammonium salts such as tetraethylammonium dodecylbenzyl sulfate.
Details of other reaction formats are well known in various documents and patent publications.

  The substrate used in the hologram recording medium of the present invention is preferably formed by either injection molding or extrusion molding, and the characteristics of the present invention are exhibited in any molding method. In particular, it is preferably formed by injection molding.

  The polycarbonate resin composition used in the hologram recording medium of the present invention is a conventionally known conventional method (solution polymerization method, melting method), considering that the purpose of use is the production of an optical molded product such as a hologram recording medium substrate. It is preferable to remove impurities and foreign matters such as unreacted components by performing filtration in a solution state after the production by a polymerization method or the like. Further, in the extrusion process (pelletizing process) for obtaining a pellet-like polycarbonate resin for use in injection molding (including injection compression molding), foreign matters are removed by passing a sintered metal filter or the like in the molten state. Is desirable. As the filter, those having a filtration accuracy of 10 μm or less are preferably used. In any case, it is necessary that the raw material resin before injection molding (including injection compression molding) has a low content of foreign matters, impurities, solvents and the like as much as possible.

  Furthermore, in order to produce such low foreign matter pellets, in addition to the above, a manufacturing device such as an extruder or pelletizer should be installed in a clean air atmosphere, and the cooling water for the cooling bath should be reduced in the amount of foreign matter. It is preferable that the raw material supply hopper, the supply flow path, the storage tank for the obtained pellets, and the like be filled with cleaner air or the like. For example, it is appropriate to adopt a method similar to that proposed in JP-A-11-21357. Further, a method of pouring an inert gas typified by nitrogen gas into the extruder and shielding oxygen can be suitably used as a means for improving hue.

  Furthermore, in the production of such pellets, various methods already proposed for polycarbonate resins for optical molding materials are used to narrow the shape distribution of pellets, further reduce miscuts, and generate minute amounts during transportation or transportation. Further reduction of powder and reduction of bubbles (vacuum bubbles) generated in the strands and pellets can be appropriately performed. These prescriptions can further increase the molding cycle and reduce the occurrence rate of defects such as silver. Moreover, although the shape of a pellet can take common shapes, such as a cylinder, a prism, and a spherical shape, it is a cylinder (including an elliptical column) more preferably. The diameter of such a cylinder is preferably 1 to 5 mm, more preferably 1.5 to 4 mm, and still more preferably 2 to 3.3 mm. In the elliptic cylinder, the ratio of the minor axis to the major axis is preferably 60% or more, more preferably 65% or more. On the other hand, the length of the cylinder is preferably 1 to 30 mm, more preferably 2 to 5 mm, and still more preferably 2.5 to 3.5 mm.

<Specific viscosity>
The specific viscosity of the polycarbonate resin composition used in the hologram recording medium of the present invention is preferably in the range of 0.19 to 0.53, and more preferably in the range of 0.21 to 0.36. . A polycarbonate resin composition having such a specific viscosity can provide sufficient strength as a hologram recording medium substrate, and has good moldability. When the specific viscosity is smaller than 0.19, the strength is insufficient as a substrate for a hologram recording medium, which is not preferable. When the specific viscosity is larger than 0.53, the moldability deteriorates, which is not preferable. In addition, the specific viscosity in this invention measures the intrinsic viscosity in 20 degreeC of the solution which melt | dissolved 0.7 g of polycarbonate resin compositions in 100 ml of methylene chloride, and was computed from the following formula.
ηsp / c = [η] + 0.45 × [η] ² c
ηsp: specific viscosity η: intrinsic viscosity c: constant (= 0.7)

<Glass transition temperature>
The glass transition temperature of the polycarbonate resin composition used in the hologram recording medium of the present invention is desirably 120 ° C. or higher, and more preferably 130 ° C. or higher. If the glass transition temperature is less than 120 ° C, thermal deformation is likely to occur during hologram recording or storage in the use environment, and during reproduction, the position of interference fringes during hologram recording may shift, making it impossible to reproduce information. This is not preferable. However, if the glass transition temperature exceeds 180 ° C., the fluidity is poor in the processing step such as injection molding, and the moldability is inferior. The glass transition temperature in the present invention can be measured by using a differential scanning calorimeter (DSC) at a heating rate of 20 ° C./min in accordance with JIS K7121.

<Photoelastic constant>
The polycarbonate resin composition used for the hologram recording medium of the present invention is 45 × 10 ⁻¹² m ² / N (45 × 10 ⁻¹³ cm ² / dyne) or less, more preferably 40 × 10 ⁻¹² m ² / N ( It can be satisfied that the photoelastic coefficient is less than 40 × 10 ⁻¹³ cm ² / dyne). By having the value of the photoelastic coefficient within such a range, the birefringence due to the residual stress is reduced, and it is advantageously used particularly in a hologram recording medium.

<Orientation birefringence>
The polycarbonate resin composition used in the hologram recording medium of the present invention preferably has an absolute value of orientation birefringence measured by a method described later of less than 5.0 × 10 ⁻³ . When the value of the orientation birefringence is in such a range, the birefringence due to the orientation becomes small, and it is advantageously used particularly in a hologram recording medium.

<Bending elastic modulus>
The polycarbonate resin composition used in the hologram recording medium of the present invention preferably has a flexural modulus value measured in accordance with ASTM D-0790 of 2900 (comparative example 2: 2870) MPa or more. When the flexural modulus is less than 2900 MPa, the effect of suppressing shrinkage deformation caused by radical polymerization of the recording layer during hologram recording is reduced, which is not preferable. On the other hand, if the flexural modulus is larger than 3,500 MPa, transferability at the time of molding is deteriorated, the flatness of the substrate surface is inferior, and irregular reflection of the laser at the time of hologram recording occurs, which is not preferable.

<Moisture permeability coefficient>
The polycarbonate resin composition used in the hologram recording medium of the present invention has a moisture permeability coefficient of 2.0 × 10 4 after 24 hours at 40 ° C., 90% RH, from a moisture permeability cup method using calcium chloride in accordance with JIS-Z0208. ^It is preferably ⁻¹⁰ cm ³ · cm / cm ² / sec / cmHg or less. When the value of the moisture permeability coefficient is in such a range, when the hologram recording medium is left under normal temperature and normal humidity, the moisture transmitted from the substrate is reduced, the recording layer is prevented from being deteriorated, and the shelf life of the hologram recording medium is improved. be able to.

<Oxygen transmission coefficient>
The polycarbonate resin composition used for the hologram recording medium of the present invention has an oxygen transmission coefficient of 5.0 × 10 ⁻¹¹ cm ³ · at 23 ° C. measured using a differential pressure method in accordance with JIS-K-7126-1. it is preferably not more than ^{cm / cm 2 / sec / cmHg} . When the oxygen transmission coefficient value is within such a range, the influence of oxygen transmitted from the substrate during hologram recording on the recording layer is reduced, and in particular, the recording performance of the hologram recording medium can be improved.

<Method for producing substrate for hologram recording medium>
An injection molding machine (including an injection compression molding machine) is used when producing a hologram recording medium substrate from an optical molding material comprising the polycarbonate resin composition, more specifically, an optical molding material having a pellet shape. . Although this injection molding machine may be generally used, it has low adhesion to the resin as a cylinder or a screw from the viewpoint of suppressing the generation of carbides and improving the reliability of the hologram recording medium substrate, and is resistant to corrosion. It is preferable to use a material made of a material exhibiting properties and wear resistance. The shape of the hologram recording medium substrate can be adapted to a two-dimensional or three-dimensional shape such as a sheet shape, a film shape, or a disk shape by using various processing methods.

As conditions for injection molding, the cylinder temperature is preferably 300 to 450 ° C, more preferably 320 to 390 ° C, and the mold temperature is preferably 50 to 180 ° C, more preferably 100 to 150 ° C. An optically excellent hologram recording medium substrate can be obtained.
The environment in the molding process is preferably as clean as possible in view of the object of the present invention. It is also important to take into consideration that the material used for molding is sufficiently dried to remove moisture, and that no retention that causes decomposition of the molten resin occurs.

<Manufacture of hologram recording medium>
The method for producing a hologram recording medium of the present invention comprises adding a radical polymerizable monomer, a photo radical polymerization initiator, and a curing agent for curing the three-dimensional crosslinked polymer to a three-dimensional crosslinked polymer serving as a matrix, and a recording layer material A step of preparing a solution, and a step of applying the recording layer material solution onto a substrate made of a specific polycarbonate resin composition and curing to form a recording layer.

  An epoxy compound is used as the compound that forms the three-dimensional crosslinked polymer forming the matrix. Specifically, as the epoxy compound, 1,4-butanediol diglycidyl ether, 1,6-hexanediol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol Diglycidyl ether, diepoxy octane, resorcinol diglycidyl ether, diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, 3,4-epoxycyclohexenylmethyl-3 ', 4'-epoxycyclohexene carboxylate, and epoxy propoxy Examples include propyl-terminated polydimethylsiloxane.

  Examples of the radical polymerizable compound include compounds having an ethylenically unsaturated double bond. Examples thereof include unsaturated carboxylic acids, unsaturated carboxylic acid esters, unsaturated carboxylic acid amides, and vinyl compounds. More specifically, acrylic acid, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, stearyl acrylate, cyclohexyl acrylate, bicyclopentenyl Acrylate, phenyl acrylate, isobornyl acrylate, adamantyl acrylate, methacrylic acid, methyl methacrylate, propyl methacrylate, butyl methacrylate, phenyl methacrylate, phenoxyethyl acrylate, chlorophenyl acrylate, adamantyl methacrylate, isobornyl methacrylate, N-methylacrylamide, N, N-dimethylacrylamide, N, N-methylenebisacrylamide, acryloyl Ruphorin, vinyl pyridine, styrene, bromostyrene, chlorostyrene, tribromophenyl acrylate, trichlorophenyl acrylate, tribromophenyl methacrylate, trichlorophenyl methacrylate, vinyl benzoate, 3,5-dichlorovinyl benzoate, vinyl naphthalene, vinyl naphthoate, naphthyl Methacrylate, naphthyl acrylate, N-phenyl methacrylamide, N-phenyl acrylamide, N-vinyl pyrrolidinone, N-vinyl carbazole, 1-vinyl imidazole, bicyclopentenyl acrylate, 1,6-hexanediol diacrylate, pentaerythritol triacrylate, penta Erythritol tetraacrylate, dipentaerythritol hexaacrylate, di Chi glycol diacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, tripropylene glycol diacrylate, propylene glycol trimethacrylate, include N- vinylcarbazole and N- vinylpyrrolidone.

Examples of the photo radical polymerization initiator include imidazole derivatives, organic azide compounds, titanocenes, organic peroxides, and thioxanthone derivatives. Specifically, benzyl, benzoin, benzoin ethyl ether, benzoin isopropyl ether, benzoin butyl ether, benzoin isobutyl ether, 1-hydroxycyclohexyl phenyl ketone, benzyl methyl ketal, benzyl ethyl ketal, benzyl methoxy ethyl ether, 2,2′-diethyl Acetophenone, 2,2′-dipropylacetophenone, 2-hydroxy-2-methylpropiophenone, p-tert-butyltrichloroacetophenone, thioxanthone, 2-chlorothioxanthone, 3,3′4,4′-tetra (t- Butylperoxycarbonyl) benzophenone, 2,4,6-tris (trichloromethyl) 1,3,5-triazine, 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) 1,3,5-triazine, 2-[(p-methoxyphenyl) ethylene] -4,6-bis (trichloromethyl) 1,3,5-triazine, Irgacure 149, 184, 369 manufactured by Ciba Specialty Chemicals, 651, 784, 819, 907, 1700, 1800, 1850 and the like, di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide, t-butyl peroxyacetate, t-butyl peroxide Oxyphthalate, t-butylperoxybenzoate, acetyl peroxide, isobutyryl peroxide, decanoyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, methyl ethyl keto Peroxide, and cyclohexanone peroxide.
If necessary, sensitizing dyes such as cyanine, merocyanine, xanthene, coumarin, and eosin, silane coupling agents, and plasticizers may be added.

  In order to apply the recording layer solution containing the above three-dimensional crosslinked polymer, radical polymerizable monomer, and photopolymerization initiator to the substrate, a casting method or a spin coating method can be employed. It is also possible to arrange two glass substrates or plastic substrates through resin spacers and inject the recording layer material solution into the gap. The three-dimensional crosslinking of the matrix polymer proceeds at room temperature with aliphatic primary amines, but may be heated to about 30 ° C. to 150 ° C. depending on the reactivity of the curing agent. The film thickness of the recording layer is preferably in the range of 20 μm to 2 mm. If it is less than 20 μm, it is difficult to obtain a sufficient storage capacity, and if it exceeds 2 mm, the sensitivity and diffraction efficiency are lowered. More preferably, the film thickness of the recording layer is in the range of 50 μm to 1 mm. When the recording layer may dissolve or erode the substrate, a protective layer such as a silicon film or a zinc sulfide-silicon film may be formed between the substrate and the recording layer by a technique such as sputtering. In that case, the thickness of the protective layer is preferably 10 nm to 500 nm.

<Hologram recording and playback method>
In the hologram recording medium according to the embodiment of the present invention, hologram recording / reproduction is performed by causing information light and reference light to interfere with each other inside the recording layer. As the hologram to be recorded, both transmission type and reflection type holograms can be used. The interference method between the information beam and the reference beam can be a two-beam interference method or a coaxial interference method (collinear, coaxial method).

  In the hologram recording medium of the present invention, when a transmission type is used, for example, recording is performed as shown in FIG. FIG. 1 is a schematic diagram showing a transmission hologram recording medium used in the two-beam interference method, and its information light and reference light. As shown in the drawing, the hologram recording medium 3 includes a pair of transparent substrates 6 made of plastic such as glass or polycarbonate, and a spacer 5 and a recording layer 4 sandwiched therebetween. The recording layer 4 contains a three-dimensional polymer matrix as described above and a radically polymerizable compound and a radical photopolymerization initiator.

  In the hologram recording medium of the present invention, when a reflection type is used, for example, recording is performed as shown in FIGS. 2 and 3 are schematic views showing a reflection type hologram information recording medium and information light and reference light in the vicinity thereof. As shown in the figure, a pair of a light-transmitting substrate 3 and a supporting substrate 6 made of plastic such as glass or polycarbonate, a spacer 5 and a recording layer 4 sandwiched therebetween, and a reflecting layer 8 supported by the substrate 6 are provided. I have. The recording layer 4 contains a three-dimensional polymer matrix as described above, a radical polymerizable compound, and a photo radical polymerization initiator. Moreover, when recording the positional information of the recorded hologram with another wavelength, the medium which has the wavelength selection film | membrane 10 sandwiched by the gap layer 7 can also be used.

  Hereinafter, the present invention will be described in more detail with reference to specific examples. In this embodiment, a series of operations were performed in a room where light having a wavelength shorter than 600 nm was shielded so that the recording layer was not exposed.

  Since the substrate formed from the polycarbonate resin composition used in the hologram recording medium of the present invention exhibits low birefringence, high rigidity, low moisture permeability, and low oxygen permeability, the industrial effect exerted by the substrate is exceptional. Furthermore, the hologram recording medium using this substrate has excellent multiplex recording performance, small deformation due to the shrinkage of the recording layer during hologram recording, small deterioration in recording performance due to the effect of oxygen transmitted from the substrate, and long-term storage. It is possible to reduce the influence of moisture transmitted from the substrate due to the above and improve the shelf life of the hologram recording medium. Therefore, the effectiveness as a hologram recording medium is clear.

  Hereinafter, although an example is given and explained in detail, the present invention is not limited to this unless it exceeds the purpose. In the examples and comparative examples, “parts” is parts by weight. Evaluation was according to the following method.

(1) Glass transition temperature Using a thermal analysis system DSC-2910 manufactured by TA Instruments, in accordance with JIS K7121, under a nitrogen atmosphere (nitrogen flow rate: 40 ml / min), temperature increase rate: 20 ° C./min. Measured with

(2) Specific viscosity 0.7 g of polycarbonate resin composition pellets were dissolved in 100 ml of methylene chloride, and the specific viscosity (ηsp) of the solution at 20 ° C. was measured.

(3) Flexural modulus Bending test pieces were molded at a cylinder temperature of 280 to 340 ° C. and a mold temperature of 80 to 100 ° C. using an injection molding machine J-75E3 manufactured by Nippon Steel Works. The bending test was performed according to ISO178.

(4) Photoelastic coefficient 5 g of the polycarbonate resin composition pellets were dissolved in 100 ml of methylene chloride, and the solution was cast on a flat glass plate and left overnight to prepare a cast film. After the film was dried at 60 ° C. for 2 hours, a film having a length of 50 mm, a width of 20 mm, and an average thickness of 150 μm was prepared, and measurement was performed by setting a photoelastic stage on an ellipsometer M-220 manufactured by JASCO Corporation. It was. As the measurement conditions, a load of 1 N or less was applied to the film, and the phase difference at that time was measured. Measurement was performed at five points, and the photoelastic coefficient was calculated according to the following formula.
Re = F × c × d
Re: phase difference [nm], F: stress [N / m ² ], c: photoelastic constant [m ² / N],
d: Thickness [nm]

(5) Oriented birefringence index The polycarbonate resin composition pellets are dissolved in methylene chloride, and a 15 wt% methylene chloride solution is cast on a flat glass plate to obtain an average thickness of 60 μm and a thickness variation of 1. A 1 μm film was prepared. The end of the film was cut off to a width of 10 mm and a length of 100 mm, and the film was dried at 120 ° C. for 2 hours in order to remove the methylene chloride solution. The obtained film was uniaxially stretched at a predetermined stretching temperature (glass transition temperature + 10 ° C.) in the length direction at a stretching speed of 15 mm / min to produce a double-stretched film having a width of 7.1 mm, an average thickness of 42 μm, and a length of 200 mm. Obtained. When the film was observed with a polarizing plate, it was confirmed that the film was uniformly stretched. Thereafter, the phase difference was measured with an ellipsometer (model: M-220) manufactured by JASCO Corporation. The orientation birefringence was calculated from the obtained retardation by the following formula.
Δn × 10 ⁻³ = Ret / d
Δn: orientation birefringence Ret: retardation [nm] d: film thickness [μm]

(6) Moisture permeability coefficient It cut into circle using the produced said polycarbonate film. In accordance with JIS-Z0208, calcium chloride was put into a moisture permeability test jig container, a polycarbonate film cut into a circle was placed, and wax was poured around and hardened. In this state, the container weight was measured. Then, the container was put into a constant temperature and humidity chamber of 40 ° C. and 90% RH, taken out after 24 hours, and the container weight after being left in a room at 23 ° C. and 55% RH for 15 minutes was measured. The moisture permeability coefficient was calculated.

(7) Oxygen Permeability Coefficient The oxygen permeability coefficient at 23 ° C. was measured from the differential pressure method using the produced polycarbonate film according to JIS-K-7126-1.

(8) Diagonal incidence birefringence retardation After drying the polycarbonate resin composition pellets at 120 ° C. for 5 hours, using an injection molding machine (M35B-D-DM manufactured by Meiki Seisakusho Co., Ltd.), the diameter is 120 mmφ, the thickness A 0.6 mm optical disk substrate (without pattern) was molded. A 3 cm square plate was cut from the substrate so that a radius of 40 mm was the center. A phase difference at the time of vertical incidence at a wavelength of 532 nm and a change amount of the phase difference at an incident angle of 30 ° were measured with an ellipsometer (model: M-220) manufactured by JASCO.
ΔRe = Re (30 °) −Re (0 °)
ΔRe: phase difference variation [nm], Re (30 °): phase difference at an incident angle of 30 ° [nm]
Re (0 °): Phase difference at normal incidence [nm]

(9) Light transmittance The transmittance at a wavelength of 532 nm was measured with a spectrophotometer (model: U-4100) manufactured by Hitachi High-Technologies Corporation using the square plate prepared in (8).

(10) Preparation of hologram recording layer 1,6-hexanediol diglycidyl ether was used as a three-dimensional crosslinked polymer. Further, polyethylene glycol diacrylate was used as a photopolymerizable monomer. The monomer is liquid at room temperature. 3 parts by weight of Irgacure-784 (manufactured by Ciba Specialty Chemicals) as a photopolymerization initiator was added to and mixed with 100 parts by weight of polyethylene glycol diacrylate. A hologram recording recording layer was prepared by mixing at room temperature so that the ratio of the matrix material was 67% by weight and the ratio of the photopolymerizable monomer was 33% by weight with respect to the total amount of the hologram recording layer solution.

(11) Production of Hologram Recording Medium The prepared hologram recording layer solution was used as a spacer for a polyethylene terephthalate sheet and injected between two substrates. This was shielded from light and held at 50 ° C. for 24 hours to produce a transmission hologram recording medium having a recording layer having a thickness of 200 μm.

(12) Evaluation of hologram recording performance For evaluation of the produced hologram recording medium, a hologram evaluation apparatus (model: SHOT-500) manufactured by Pulstec was used. The created hologram recording medium was set in a sample folder, and an Nd: YAG laser having a wavelength of 532 nm and an irradiation intensity of 7 mW / cm ² was used for recording and reproduction. The hologram recording conditions were such that the total exposure was 500 mJ / cm ² . The multiplex recording condition was that the reference beam was fixed, the incident angle of the information beam was changed by 1 ° from −6 ° to 6 °, and 13 holograms were recorded in a multiplexed manner. To reproduce the recorded hologram, reference light was used, and the incident angle was changed by 0.2 °, and the ratio of the diffracted light intensity to the incident light intensity was measured as the diffraction efficiency. A dynamic range (M / #: M number) was calculated from the obtained diffraction efficiency by the following formula.

ｉ：ｉ番目のホログラム（１〜１３）、η：ｉ番目のホログラムの回折効率

i: i th hologram (1-13), η: diffraction efficiency of i th hologram

(13) Shrinkage rate of the hologram recording layer The shrinkage rate of the hologram recording layer was calculated from the difference between the incident angle of the reference beam that showed the peak value of the diffraction efficiency during reproduction and the incident angle of the information beam during recording by the following formula.

Ａ_０：再生時における回折効率のピーク値を示した参照光の入射角度［°］
Ａ_１：記録時における情報光の入射角度［°］

A ₀ : incident angle [°] of the reference beam indicating the peak value of the diffraction efficiency during reproduction
A ₁ : Information light incident angle [°] during recording

(14) Shelf life evaluation After producing a hologram recording medium by the same method as in the above (10) and (11), after standing for 1 month in a room at 23 ° C. and 50% RH, SHOT-500 manufactured by Pulstec Corporation is used. The same measurement as in (12) above was performed, and the diffraction efficiency was measured. The dynamic range (M / #: M number) was calculated using the obtained diffraction efficiency.

[Example 1]
A reactor equipped with a thermometer, a stirrer and a reflux condenser was charged with 238.0 parts of a 48% aqueous sodium hydroxide solution and 1168.8 parts of ion-exchanged water, and 1,1-bis (4-hydroxy-3) was added thereto. -Methylphenyl) After dissolving 213.5 parts of cyclohexane and 0.43 part of hydrosulfite, 797.2 parts of methylene chloride was added, and 100.0 parts of phosgene was added at 15 to 25 ° C. over about 60 minutes with stirring. Infused. After completion of the phosgene blowing, 29.7 parts of 48% aqueous sodium hydroxide and 4.87 parts of p-tert-butylphenol were added, stirring was resumed, and after emulsification, 0.25 parts of triethylamine was added, and the mixture was further added at 28-33 ° C. The reaction was terminated by stirring for a period of time. After completion of the reaction, the product is diluted with methylene chloride, washed with water, acidified with hydrochloric acid, washed with water, and further washed with water until the conductivity of the aqueous phase becomes substantially the same as that of ion-exchanged water. Obtained. Next, this solution is passed through a filter having an aperture of 0.3 μm, and further dropped into warm water in a kneader with an isolation chamber having a foreign matter outlet at the bearing, and the polycarbonate resin is flaked while distilling off methylene chloride. The liquid-containing flakes were pulverized and dried to obtain a powder. Thereafter, tris (2,4-di-tert-butylphenyl) phosphite is added to the powder so as to be 0.0025% by weight and stearic acid monoglyceride to be 0.05% by weight. The powder was melt-kneaded while degassing with a vent type twin screw extruder [KTX-46, manufactured by Kobe Steel, Ltd.] to obtain polycarbonate resin composition pellets. Table 1 shows the glass transition temperature, specific viscosity, flexural modulus, photoelastic coefficient, and birefringence of the pellet. From this pellet, an injection molding machine (M35B-D-DM manufactured by Meiki Seisakusho Co., Ltd.), a mold with a cavity thickness of 1.2 mmt, a diameter of 120 mm, and a flat stamper without a pattern, a cylinder set temperature of 360 ° C., a mold An optical disk substrate was molded under the conditions of a temperature of 103 ° C., a filling time of 0.2 seconds, a cooling time of 15 seconds, and a clamping force of 30 tons. A 3 cm square plate was cut from this substrate so that the center had a radius of 40 mm. The obliquely incident birefringence phase difference was measured with an ellipsometer (model: M-220) manufactured by JASCO Corporation using the obtained square plate, and the results are shown in Table 1. The prepared hologram recording layer solution was injected between two square plates sandwiching a polyethylene terephthalate sheet spacer. This was shielded from light and held at 50 ° C. for 24 hours to produce a transmission hologram recording medium having a recording layer having a thickness of 200 μm. For evaluation of the hologram recording medium, 13 holograms were multiplexed and recorded using a hologram evaluation apparatus (model: SHOT-500) manufactured by Pulstec. Thereafter, reproduction was performed by changing the incident angle of the reference light by 0.2 °, and the diffraction efficiency was measured. The dynamic range (M / #) and shrinkage rate were calculated using the obtained diffraction efficiency and are shown in Table 1. In addition, after producing a hologram recording medium by the same method, after being left in a room at 23 ° C. and 50% RH for one month, multiplex recording similar to the above was performed using SHOT-500 manufactured by Pulstec Corporation, The diffraction efficiency was measured. The dynamic range (M / #) was calculated using the obtained diffraction efficiency and listed in Table 1.

[Example 2]
The same operation as in Example 1 except that 192.2 parts of 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane and 16.5 parts of 2,2′-bis (4-hydroxyphenyl) propane were used. The polycarbonate resin composition pellets having the characteristics described in Table 1 were obtained. Further, a hologram recording medium was prepared and evaluated in the same manner as in Example 1 except that the mold temperature was 104 ° C., and the results are shown in Table 1.

[Example 3]
Except for 192.2 parts of 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane and 26.7 parts of 4,4 ′-(m-phenylenediisopropylidene) diphenol, all are the same as in Example 1. The polycarbonate resin composition pellets having the characteristics described in Table 1 were obtained. Further, a hologram recording medium was prepared and evaluated in the same manner as in Example 1 except that the mold temperature was 102 ° C., and the results are shown in Table 1.

[Example 4]
The same operations as in Example 1 were conducted except that 192.2 parts of 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane and 23.5 parts of 1,1 ′-(4-hydroxyphenyl) decane were used. Then, a polycarbonate resin composition pellet having the characteristics shown in Table 1 was obtained. Further, a hologram recording medium was prepared and evaluated in the same manner as in Example 1 except that the mold temperature was 97 ° C., and the results are shown in Table 1.

[Comparative Example 1]
The same operation as in Example 1 except that 149.5 parts of 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane and 49.3 parts of 2,2′-bis (4-hydroxyphenyl) propane were used. The polycarbonate resin composition pellets having the characteristics described in Table 1 were obtained. Further, a hologram recording medium was prepared and evaluated in the same manner as in Example 1 except that the mold temperature was set to 105 ° C., and the results are shown in Table 1.

[Comparative Example 2]
The same as Example 1 except that 149.5 parts of 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane and 80.1 parts of 4,4 ′-(m-phenylenediisopropylidene) diphenol were used. The polycarbonate resin composition pellets having the characteristics described in Table 1 were obtained. Further, a hologram recording medium was prepared and evaluated in the same manner as in Example 1 except that the mold temperature was 101 ° C., and the results are shown in Table 1.

[Comparative Example 3]
The same operation as in Example 1 was conducted except that 149.5 parts of 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane and 70.5 parts of 1,1 ′-(4-hydroxyphenyl) decane were used. Then, a polycarbonate resin composition pellet having the characteristics shown in Table 1 was obtained. Further, a hologram recording medium was prepared and evaluated in the same manner as in Example 1 except that the mold temperature was set to 74 ° C., and the results are shown in Table 1.

[Comparative Example 4]
A hologram recording medium was prepared and evaluated in the same manner as in Example 1 except that Teijin Chemicals Panlite AD-5503 was used as the polycarbonate resin composition pellet and the mold temperature was changed to 110 ° C. The results are shown in Table 1. .

[Comparative Example 5]
A hologram recording medium was prepared and evaluated in the same manner as in Example 1 except that amorphous polyolefin pellets (ZEONEX 480R manufactured by Nippon Zeon Co., Ltd.) were used instead of the polycarbonate resin composition pellets, and the mold temperature was 103 ° C. Are listed in Table 1.

* 1 Bisphenol-OCZ
: 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane * 2 Bisphenol-M
: 4,4 '-(m-phenylenediisopropylidene) diphenol * 3 Bisphenol-A
: 2,2'-bis (4-hydroxyphenyl) propane * 4 Bisphenol-DED
: 1,1′-bis (4-hydroxyphenyl) decane

It is the schematic which shows the transmission type hologram recording medium used with a two-beam interference system, its information light, and reference light. It is an example of the schematic which shows a reflection type hologram information recording medium, and the information beam and reference beam in the vicinity. It is an example of the schematic which shows a reflection type hologram information recording medium, and the information beam and reference beam in the vicinity.

Explanation of symbols

1 information light 2 reference light 3 light-transmitting substrate 1
4 Recording layer 5 Spacer 6 Support substrate 2
7 Gap layer 8 Reflective film 9 Objective lens 10 Wavelength selection film

Claims (12)

Interference is achieved by superimposing information light provided with information as a two-dimensional image and reference light capable of interfering with the information light inside the recording medium, recording information as an interference pattern, and irradiating the reference light during reproduction. In a recording / reproducing system using holography that reproduces image information by diffracting light with fringes, a light transmissive substrate 1 and a substrate 2 serving as a support, and a three-dimensional bridge formed between the substrate 1 and the substrate 2 In a hologram recording medium composed of a recording layer containing a polymer matrix, a radical polymerizable compound and a photo radical polymerization initiator,
The light transmissive substrate 1 and the support substrate 2 are (A) a structural unit [A] represented by the following formula [1] and

(In the formula, R ^{1 and} R ² are each independently a hydrogen atom, a hydrocarbon group having 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom.)
(B) The following formula [2]

(Wherein R ^{3 to} R ⁶ are each independently a hydrogen atom, an alkyl group that may contain an aromatic group having 1 to 9 carbon atoms, an aryl group having 6 to 10 carbon atoms, or 1 to 1 carbon atom) Represents an alkoxy group of 6. W represents a single bond, an alkylene group having 1 to 15 carbon atoms, an alkylene group which may contain an aromatic group having 1 to 20 carbon atoms, or an oxygen atom.)
(C) the following formula [3] with respect to the polycarbonate resin comprising the structural unit [B] represented by the formula (B):

(Wherein R ⁷ represents a (t + u) -valent aliphatic hydrocarbon group having 1 to 22 carbon atoms, R ⁸ represents an alkyl group having 12 to 22 carbon atoms, t represents 0 or a positive integer, u represents a positive integer, and (t + u) represents an integer of 1 to 6.)
Higher fatty acid esters of monohydric and / or polyhydric alcohols represented by 0.01 to 1% by weight, and (D) phosphorus stabilizers 0.0001 to 0.5% by weight
A hologram recording medium comprising a substrate made of a polycarbonate resin composition containing 2. The hologram recording medium according to claim 1, wherein the light transmissive substrate 1 and the support substrate 2 are (A) a structural unit [A] represented by the following formula [1] and

(Wherein R ^{1 and} R ² are each independently a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.)
(B) The following formula [2]

(In the formula, R ^{3 to} R ⁶ each independently represent a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, an aryl group having 6 to 10 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms. W represents a single bond, an alkylene group having 1 to 15 carbon atoms, or an alkylene group that may contain an aromatic group having 1 to 15 carbon atoms.)
(C) the following formula [3] with respect to the polycarbonate resin comprising the structural unit [B] represented by the formula (B):

(Wherein R ⁷ represents a (t + u) -valent aliphatic hydrocarbon group having 1 to 22 carbon atoms, R ⁸ represents an alkyl group having 12 to 22 carbon atoms, t represents 0 or a positive integer, u represents a positive integer, and (t + u) represents an integer of 1 to 6.)
Higher fatty acid esters of monohydric and / or polyhydric alcohols represented by 0.01 to 1% by weight, and (D) phosphorus stabilizers 0.0001 to 0.5% by weight
2. The hologram recording medium according to claim 1, wherein the hologram recording medium is a substrate made of a polycarbonate resin composition.   The hologram recording medium according to claim 1 or 2, wherein the hologram recording medium is a substrate made of a polycarbonate resin composition in which the proportion of the structural unit (A) represented by the general formula [1] in all the structural units is 90 to 100 mol%.   The structural unit (A) represented by the general formula [1] is a structural unit derived from 1,1-bis (4-hydroxy-3-methylphenyl) cyclohexane. The hologram recording medium according to Item.   The structural unit (B) represented by the general formula [2] is 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) decane, and 4,4 ′-( A substrate for a hologram recording medium comprising an aromatic polycarbonate resin according to any one of claims 1 to 4, which is a structural unit derived from at least one selected from the group consisting of (m-phenylenediisopropylidene) diphenol. .   The structural unit (B) represented by the general formula [2] is selected from the group consisting of 1,1-bis (4-hydroxyphenyl) decane and 4,4 ′-(m-phenylenediisopropylidene) diphenol. The substrate for a hologram recording medium comprising the aromatic polycarbonate resin according to any one of claims 1 to 5, which is a structural unit derived from at least one selected.   The higher fatty acid ester of monohydric and / or polyhydric alcohol (C) represented by the general formula [3] is mono- or diester of glycerin and stearic acid, mono- or diester of glycerin and behenic acid, pentaerythritol The hologram recording medium according to claim 1, wherein the hologram recording medium is at least one selected from the group consisting of a total ester of styrene and stearic acid, and a total ester of pentaerythritol and behenic acid.   The monovalent and / or polyhydric alcohol higher fatty acid ester of (C) represented by the general formula [3] is stearic acid monoglyceride or pentaerythritol tetrastearate. The hologram recording medium according to item 1.   The phosphorus stabilizer (D) is tetrakis (2,4-di-t-butylphenyl) 4,4′-biphenylene-diphosphonate, tetrakis (2,4-di-t-butylphenyl) 4, Mixtures of 3′-biphenylene-di-phosphonite and tetrakis (2,4-di-t-butylphenyl) 3,3′-biphenylene-di-phosphonite, phosphoric acid, phosphorous acid, trimethyl phosphate, tris (2,4 The hologram recording medium according to claim 1, which is at least one selected from the group consisting of (di-t-butylphenyl) phosphite and trisnonylphenyl phosphite.   The phosphorus stabilizer of (D) is trisnonylphenyl phosphite, tris (2,4-di-tert-butylphenyl) phosphite, and tetrakis (2,4-di-tert-butylphenyl) -4, The hologram recording medium according to claim 1, which is at least one selected from the group consisting of 4-diphenylenephosphonite. Measured according to JIS-Z0208 at a temperature of 40 ° C., a humidity of 90% RH, and a moisture permeability coefficient in a 24-hour treatment is 2.0 × 10 ⁻¹⁰ cm ³ · cm ² / sec / cmHg or less, and JIS The oxygen permeation coefficient at a temperature of 23 ° C. measured in accordance with the differential pressure method of −K7126-1 is 5.0 × 10 ⁻¹¹ cm ³ · cm ² / sec ² / cmHg or less. 2. The hologram recording medium according to claim 1. Interference is achieved by superimposing information light provided with information as a two-dimensional image and reference light capable of interfering with the information light inside the recording medium, recording information as an interference pattern, and irradiating the reference light during reproduction. In a recording / reproducing system using holography that reproduces image information by diffracting light with fringes, a light transmissive substrate 1 and a substrate 2 serving as a support, and a three-dimensional bridge formed between the substrate 1 and the substrate 2 The light transmissive substrate 1 and the support substrate 2 used in a hologram recording medium composed of a recording layer containing a polymer matrix, a radical polymerizable compound and a photo radical polymerization initiator,
(A) a structural unit [A] represented by the following formula [1] and

(In the formula, R ^{1 and} R ² are each independently a hydrogen atom, a hydrocarbon group having 1 to 9 carbon atoms which may contain an aromatic group, or a halogen atom.)
(B) The following formula [2]

(C) the following formula [3] with respect to the polycarbonate resin comprising the structural unit [B] represented by the formula (B):

(In the formula, R ⁵ represents a (t + u) -valent aliphatic hydrocarbon group having 1 to 22 carbon atoms, R ⁶ represents an alkyl group having 12 to 22 carbon atoms, t represents 0 or a positive integer, u represents a positive integer, and (t + u) represents an integer of 1 to 6.)
Higher fatty acid esters of monohydric and / or polyhydric alcohols represented by 0.01 to 1% by weight, and (D) phosphorus stabilizers 0.0001 to 0.5% by weight
A substrate for a holographic recording medium, which is a substrate formed from a polycarbonate resin composition containing

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