JP2015185186A - Optical disk substrate and optical disk - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk substrate and an optical disk that use a polymer having a β-phellandrene, which is a material obtainable from microorganisms, plants or the like such as carbon-neutral materials, as monomers.SOLUTION: In an optical disk substrate, (1) a β-phellandrene polymer with specific gravity equal to or more than 0.85 and less than 1.0 and transmittance equal to or more than 90% of light with a wavelength of 400 nm to 850 nm is included at 50 to 100 mass% relative to total mass of the optical disk substrate; (2) a number-average molecular weight Mn of the β-phellandrene polymer is equal to or more than 40,000; (3) at least a portion of olefinic carbon-carbon double bonds owned by the β-phellandrene polymer is hydrogenated; and (4) an optical disk includes the optical disk substrate, and a signal recording surface is formed in at least one surface of the optical disk substrate.

Description

  The present invention relates to an optical disk substrate using a β-ferrandylene polymer and an optical disk including the optical disk substrate.

  Conventionally, polystyrene (PS), polymethyl methacrylate (PMMA), and the like have been developed as materials for optical disc substrates, optical fibers, plastic lenses and the like as high refractive index plastics having excellent light transmittance. However, PS has a problem of low heat resistance and solvent resistance. In addition, PMMA has higher heat resistance than PS, but the problem of low solvent resistance is the same as that of PS. Further, since it has high hygroscopicity, it has a problem of being deformed by absorbing moisture in the use environment. Further, polycarbonate (PC) has a problem that light resistance is low and birefringence is larger than that of PS or PMMA.

  In addition, alicyclic polyolefins and cyclic polyolefins are known as thermoplastic resins having excellent optical properties. Examples thereof include dicyclopentadiene-based ring-opening polymerization hydrogenated products, addition copolymers of norbornene or dicyclopentadiene and olefins (see Patent Document 1), and vinylcyclohexane-based polymers (see Patent Document 2). Among them, vinylcyclohexane polymers have high heat resistance, low water absorption, low specific gravity, and low birefringence, but they are brittle and have insufficient light resistance because they have bulky substituents in their side chains. There is no problem. Furthermore, cyclic polyolefins other than vinylcyclohexane polymers have high heat resistance and low water absorption, but have a large specific gravity and insufficient light resistance.

  Such a conventional resin material having a large specific gravity is not suitable for the purpose of reducing the weight of the optical disk substrate. In order to increase the speed of writing or reading data on an optical disk or to reduce power consumption, it is required to reduce the weight of the optical disk. By reducing the weight of the optical disk substrate, the stability when the optical disk is rotated at a high speed is increased, the load on the motor is reduced, and further, the power consumption of the motor can be reduced. Here, if it is sufficient to simply reduce the weight of the optical disk substrate, it is conceivable to reduce the thickness. However, there is a problem that the thin optical disk substrate is easily deformed and easily damaged. Therefore, there is a demand for a resin material having a small specific gravity that can be reduced in weight without reducing the mechanical strength of the optical disk substrate.

  In addition, since the monomers used as raw materials for conventional general alicyclic hydrocarbon polymers are petroleum-derived compounds, there is a need for products using carbon-neutral materials that suppress carbon dioxide emissions today. It cannot be said that it meets the needs.

  As carbon-neutral polymer materials, compounds that can be produced through biosynthetic pathways in living organisms have attracted attention. For example, a polymer having a glass transition point of 80 ° C. obtained by polymerizing β-pinene derived from terpene oil extracted from pine or the like has been proposed (Patent Document 3). However, in order to obtain a polymer having a high polymerization degree that exhibits practical strength using β-pinene as a monomer, it was necessary to polymerize in the presence of a bifunctional vinyl compound. Furthermore, it is necessary to make the polymerization temperature as low as -80 ° C to 0 ° C. In order to manufacture at a low cost and from the viewpoint of recent environmental problems, further improvement of reaction conditions and natural materials with good polymerization characteristics are required. Use was desired.

JP 2000-221328 A Japanese Patent Laid-Open No. 63-43910 Japanese Patent No. 5275633

  The present invention has been made in view of the above circumstances, and an optical disc substrate and an optical disc using a polymer containing β-ferrandrene as a monomer, which can be obtained from microorganisms, plants, and the like as carbon neutral materials. I will provide a.

＜３＞ 前記βフェランドレン重合体に、下記化学式（Ｉ−１）、（Ｉ−２）、（ＩＩ−１）及び（ＩＩ−２）で表されるβフェランドレン単位が合計５０質量％以上含有されていることを特徴とする前記＜１＞又は＜２＞に記載の光ディスク基板。

＜４＞ 前記βフェランドレン重合体の数平均分子量Ｍｎが４万以上であることを特徴とする前記＜１＞〜＜３＞の何れか一項に記載の光ディスク基板。
＜５＞ 前記βフェランドレン重合体が有するオレフィン性炭素−炭素二重結合の少なくとも一部が水素化されていることを特徴とする前記＜１＞〜＜４＞の何れか一項に記載の光ディスク基板。
＜６＞ 前記βフェランドレン重合体の水素添加率が、７０％以上であることを特徴とする前記＜５＞に記載の光ディスク基板。
＜７＞ 前記βフェランドレン重合体が、厚さ：１．０ｍｍの板における、ＡＳＴＭ−Ｇ５３に準じた１００時間の促進暴露試験において、ＹＩ（イエローインデックス）の試験前と試験後における黄変度（ΔＹＩ）が１．０以下である特性を有していることを特徴とする前記＜１＞〜＜６＞の何れか一項に記載の光ディスク基板。
＜８＞ 前記＜１＞〜＜７＞の何れか一つに記載の光ディスク基板を含み、前記光ディスク基板の少なくとも片面に信号記録面が形成されていることを特徴とする光ディスク。 <1> An optical disc substrate having a specific gravity of 0.85 or more and less than 1.0, and a β-ferrandylene polymer having a transmittance of light having a wavelength of 400 nm to 850 nm of 90% or more. An optical disk substrate comprising 50 to 100% by mass with respect to the total mass of
<2> The optical disk according to <1>, wherein the β-ferrandylene polymer is obtained by polymerizing at least one of β-ferrandolene represented by the following chemical formulas (I) and (II): substrate.

<3> The β-ferrandolene units represented by the following chemical formulas (I-1), (I-2), (II-1) and (II-2) are added to the β-ferrandylene polymer in a total of 50% by mass or more. The optical disk substrate according to <1> or <2>, wherein the optical disk substrate is contained.

<4> The optical disc substrate according to any one of <1> to <3>, wherein the β-ferrandylene polymer has a number average molecular weight Mn of 40,000 or more.
<5> At least a part of the olefinic carbon-carbon double bond of the β-ferrandylene polymer is hydrogenated, as described in any one of <1> to <4>, Optical disk substrate.
<6> The optical disk substrate according to <5>, wherein a hydrogenation rate of the β-ferrandylene polymer is 70% or more.
<7> The yellowing degree before and after the test of YI (Yellow Index) in the accelerated exposure test of 100 hours according to ASTM-G53 on a plate having a thickness of 1.0 mm when the β-ferrandylene polymer is The optical disk substrate according to any one of <1> to <6>, wherein (ΔYI) has a characteristic of 1.0 or less.
<8> An optical disc comprising the optical disc substrate according to any one of <1> to <7>, wherein a signal recording surface is formed on at least one side of the optical disc substrate.

According to the present invention, it has excellent light transmission, light weight, heat resistance, chemical resistance and mechanical strength, and further has excellent properties such as high light resistance, low water absorption, low birefringence and low photoelasticity. An optical disk substrate and an optical disk can be provided.
Since the optical disk substrate of the present invention is excellent in chemical resistance, the choice of solvents that can be used at the time of manufacturing an optical disk is widened. Further, since the manufactured optical disk is lightweight, the stability when rotated at high speed is high, and the performance of data writing and reading is improved. In addition, the load and power consumption of the motor that rotates the optical disk can be reduced. Moreover, since the mechanical strength of the optical disk is high, the optical disk can be made thin.

  The first aspect of the present invention is an optical disk substrate. The second aspect of the present invention is an optical disk using the optical disk substrate of the first aspect.

First, a method for producing a β-ferrandylene polymer that is a material of the present invention will be described.
<Method for Producing β Ferrandrene Polymer>
β-Ferlandene, which is a monomer constituting the β-ferrandylene polymer, may be extracted and purified from a living organism, or may be chemically synthesized from a petroleum-derived compound. For example, β-ferrandrene contained in essential oil obtained by steam distillation from plant seeds and roots may be used, or existing chemical substances are used as raw materials, and β-ferrandrene obtained by a known chemical synthesis method is used. Also good.

  For example, when using an existing chemical as a raw material, a known chemical synthesis method (Organic & Biomolecular Chemistry, 9 (7), 2433-2451, 2011) in which 4-Isopropylcyclohexanone is used as a starting material and synthesized via Crypron The resulting β-ferrandrene can be used.

  When chemical substances extracted from living organisms are used as materials, for example, plants or plants containing β-ferrandrene, such as Todomatsu, Ginger, Fennel, Neroli, Rosewood, Tomato, Lavender, Canadian Balsam, Angelica, etc. The extract from may be purified and used. In particular, it is preferable to use high-purity β-ferrandrene. In that case, the purity (pure content) can be increased by a method such as precision distillation or separation using a silica gel column.

  By using biologically-derived β-ferrandrene as a carbon neutral material, it is possible to reduce the environmental load in the production process and to reduce carbon dioxide emissions.

In order to increase the glass transition temperature Tg related to heat resistance by increasing the number average molecular weight Mn of β-ferrandylene polymer, a β-ferrandylene polymer was synthesized in order to achieve the purpose of obtaining excellent light transmission and mechanical strength. In this reaction system, it is preferable that the purity (pure content) of β-ferrandol in the reaction solution containing β-ferrandol is as high as possible. Further, the reaction system is more preferably a reaction system in which a compound having a double bond that interferes with the polymerization of β-ferrandrene is excluded as much as possible.
Particularly preferably, for example, a substance that reacts with a cis-type conjugated double bond such as a Diels-Alder reaction reagent is added, and a cis-type conjugated double bond substance other than β-ferrandrene is removed as an insoluble substance, thereby The purity is preferably increased by combining with precision distillation or separation using a silica gel column.

  Specifically, the content of β-ferrandol, that is, the purity (pure content) of β-ferrandol is preferably 50% by mass or more, and 70% by mass or more with respect to the total mass of the polymerizable compound in the reaction solution. Is more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 95% by mass or more. The content may be 100% by mass. Here, “purity” does not mean optical purity that distinguishes optical isomers of β-ferrandolene, but simply chemical purity that does not distinguish optical isomers of β-ferrandylene. The “polymerizable compound” means a compound having a double bond polymerizable with β-ferrandolene.

In the present specification and claims, the purity of β-ferrandol used in the reaction is a value determined by the percentage of peak area of β-ferrandol by a gas chromatography (GC) method or a GC-MS method. .
For example, a β-ferrandrene reaction solution is diluted with a chloroform solution (for high-performance liquid chromatograph manufactured by Wako Pure Chemical Industries, Ltd., purity 99.7%) so as to be 1% by mass, and a gas chromatograph analyzer (HP6890 manufactured by HEWLETT PACKARD) is used. Series GC System). At this time, DB-5 (a capillary column made by Agilent Technologies, 30 m × 0.25 mm ID × 0.25 μ) was used as a column for component separation, and the column temperature: start 50 ° C., final 300 ° C., heating rate 15 It is preferable to measure at ° C / min and injection temperature: 300 ° C. The β-ferrandol peak can be identified from the β-ferrandol standard solution or MS spectrum. It is preferable that the pure amount of β-ferrandrene is calculated as an area ratio of β-ferrandrene, where the sum of the total areas of peaks having an area value of 1000 or more observed in the GC analysis is 100.

  By adding a Lewis acid as a catalyst and dispersing well in an organic solvent constituting the reaction solution, slowly dropping high-purity β-ferrandrene, starting cationic polymerization, and reacting for a predetermined time, The intended β-ferrandylene polymer can be obtained.

  In performing cationic polymerization by such a solution polymerization method, the concentration of β-ferrandylene as a monomer is preferably 1 to 90% by mass, more preferably 10 to 80% by mass, based on the total mass of the reaction solution. More preferably, it can be adjusted to 10 to 50% by mass. When the concentration is less than 1% by mass, the productivity is low, while when it exceeds 90% by mass, it is difficult to remove the heat of polymerization.

The type of organic solvent constituting the reaction solution is not particularly limited as long as it can dissolve β-ferrandrene, and a solvent used in conventional cationic polymerization can be applied. Among these, a solvent with little chain transfer is preferable. Examples of such a solvent include halogenated hydrocarbons, aromatic hydrocarbons, and aliphatic hydrocarbons from the viewpoint of solubility and reactivity under polymerization conditions of the polymer. More specifically, for example, halogenated carbonization such as methylene chloride, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, n-propyl chloride, 1-chloro-n-butane, 2-chloro-n-butane and the like. Hydrogen solvents; aromatic hydrocarbon solvents such as benzene, toluene, xylene, anisole; aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, cyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane, decalin, etc. Can be mentioned.
As the organic solvent, one organic solvent may be used alone, or two or more organic solvents may be used in combination.

The organic solvent may be a nonpolar solvent or a polar solvent.
In order to further increase the degree of polymerization of the β-ferrandylene polymer and obtain a tough polymer, it is particularly preferable to use a nonpolar solvent. Chlorinated solvents (solvents composed of compounds having chlorine atoms) such as halogenated aliphatic hydrocarbons and halogenated aromatic hydrocarbons can be used. However, since there are some chlorinated solvents that cannot be used from the viewpoint of disposal of waste solvents, desalting of polymerized products, and recent VOC regulations, it is not always preferable from the viewpoint of environmental problems.

As the Lewis acid, a Lewis acid used in conventional cationic polymerization is applicable. For example, EtAlCl ₂ , AlCl ₃ , Et ₂ AlCl, Et ₃ Al ₂ Cl ₃ , BCl ₃ , SnCl ₄ , TiCl ₄ , Ti (OR) _4-y Cl ₄ [R represents an alkyl group or an aryl group, and y represents an integer of 1 to 3. ] Is preferable because of high reactivity and selectivity. Other than these, metal halides such as BF ₃ , BBr ₃ , AlF ₃ , AlBr ₃ , TiBr ₄ , TiI ₄ , FeCl ₃ , FeCl ₂ , SnCl ₂ , WCl ₆ , MoCl ₅ , SbCl ₅ , TeCl ₂ , ZnCl _{2 , (i-Bu) 3 Al} , (i-Bu) 2 AlCl, (i-Bu) AlCl 2, Me 4 Sn, Et 4 Sn, Bu 4 Sn, Bu 3 metal alkyl compound such as SnCl [Me represents a methyl group Et represents an ethyl group and Bu represents a butyl group. _{], Al (OR) 3-} x Cl x [R represents an alkyl group or an aryl group, x is an integer of 1 or 2. And the like.
As the Lewis acid, one Lewis acid may be used alone, or two or more Lewis acids may be used in combination.

  As the polymerization catalyst, only the above-mentioned Lewis acid may be used, but an initiator used in combination as a Lewis acid may be used. In this case, the initiator is one that reacts with a Lewis acid to generate a carbon cation, and any initiator having such characteristics may be used. Specifically, alkyl vinyl ether-hydrogen chloride adduct, chloroalkyl vinyl ether-hydrogen chloride adduct, α-chloroethylbenzene, α-chloroisopropylbenzene, 1,3-bis (α-chloroisopropyl) benzene, 1,4- Bis (α-chloroisopropyl) benzene, 1,3-bis (α-chloroisopropyl) -5-t-butylbenzene, 1,3,5-tris (α-chloroisopropyl) benzene, t-butyl chloride, 2- Chlorine initiators such as chloro-2,4,4-trimethylpentane: alkyl vinyl ether-acetic acid adduct, α-acetoxyethylbenzene, α-acetoxyisopropylbenzene, 1,3-bis (α-acetoxyisopropyl) benzene, 1, Esters such as 4-bis (α-acetoxyisopropyl) benzene Agents, alpha-hydroxy ethylbenzene, alpha-hydroxy isopropylbenzene, 1,3-bis (alpha-hydroxy isopropyl) benzene, 1,4-bis (alpha-hydroxy isopropyl) alcohol initiator such as benzene.

Moreover, you may use the electron donor used with a living cationic polymerization catalyst. As such an electron donor, known ones can be used. Specifically, ethers such as diethyl ether (Et ₂ O), methyl-t-butyl ether, dibutyl ether; ethyl acetate (EtOAc), methyl acetate, isopropyl acetate, butyl acetate, methyl isobutyrate, ethyl isobutyrate, isobutyric acid Esters such as propyl; pyridine, 2-methylpyridine, 2,6-dimethylpyridine, 2,6-di-butylpyridine, 2,6-diphenylpyridine, 2,6-di-t-butylpyridine, 2,6 -Pyridines such as di-t-butyl-4-methylpyridine; Amines such as trimethylamine, triethylamine and tributylamine; Amides such as dimethylacetamide and diethylacetamide; Sulphoxides such as dimethylsulfoxide and the like. In particular, diethyl ether and ethyl acetate are preferably used because they are economical and easy to remove after the reaction.

  The concentration of these Lewis acids in the reaction solution is preferably 0.001 to 100 parts by weight, more preferably 0.01 to 50 parts by weight, with respect to 100 parts by weight of β-ferrandolene added later. More preferably, it is 1 to 10 parts by weight. If the amount of the Lewis acid catalyst used is too small, the reaction may stop before the completion of the polymerization, and conversely if too large, it is uneconomical.

  The added β-ferrandrene may be previously dissolved in the same type of organic solvent as the organic solvent constituting the reaction solution. The temperature of the reaction solution at the time of the dropwise addition can usually be set to -120 ° C to 150 ° C, and preferably set to -90 ° C to 100 ° C. If the reaction temperature is too high, it may be difficult to control the reaction and it may be difficult to obtain reproducibility, and if it is too low, the production cost increases.

  In the method for producing a β-ferrandylene polymer, the reaction at a low temperature is advantageous in terms of increasing the degree of polymerization. For example, by reacting at −80 to 70 ° C., the number average molecular weight Mn is 100,000 or more. A β-ferrandylene polymer of about 140,000 can be easily obtained. Moreover, you may make it react at -15-40 degreeC, The beta ferrandylene polymer whose number average molecular weight Mn is about 50,000-100,000 can be obtained easily at this temperature.

  The reaction time of the cationic polymerization is not particularly limited, and may be appropriately adjusted so as to obtain a β-ferrandylene polymer having desired characteristics according to the conditions such as the type and amount of the polymerization catalyst, the reaction temperature, and the reaction equipment. it can. In general, a β-ferrandylene polymer having desired characteristics can be obtained by reacting for about 1 second to 100 hours, preferably about 10 seconds to 1 hour, more preferably about 30 seconds to 10 minutes.

  The β-ferrandol polymer used in the present invention may be a homopolymer of β-ferrandol, or a copolymer of β-ferrandol and one or more other copolymerizable monomers. May be.

  In order to terminate the reaction, a terminator may be added after the reaction for a predetermined time. As the terminator, alcohols such as methanol, ethanol, 1-propanol, isopropanol, 1-butanol, 2-butanol, isobutanol and t-butanol are preferably used. The amount of addition of the terminator is not strictly defined, but is usually 0.01 to 10 times the volume of the reaction solvent, preferably 0.1 to 1 times the volume.

  Examples of the method for separating the β-ferrandylene polymer obtained by polymerization in the reaction solution from the solvent include reprecipitation, evaporation of the solvent by heating, removal of the solvent by reduced pressure, and removal of the solvent by water vapor (coagulant). And other known methods such as removal of the deaerated solvent by an extruder can be applied.

  When it is necessary to neutralize and remove the chlorine-based Lewis acid catalyst when the polymer is separated from the solvent, a generally known neutralizing agent such as sodium hydroxide, sodium hydrogen carbonate, ammonia, etc. A neutralizing agent can be used and is not particularly limited. Furthermore, in applications where the requirements for transparency and thermal stability are severe, it is desired to sufficiently remove chlorine and neutralized salts remaining as impurities in the resulting polymer. The removal method is not particularly limited. For example, it is preferable to purify the polymer by a treatment such as water addition at the time of re-pillowing the polymer. In particular, in order to improve optical properties and electrical insulation, the content of residual neutralized salt is preferably 100 ppm or less with respect to the weight of the polymer. Especially preferably, it is 10 ppm or less.

<Β Ferrandylene Polymer>
The number average molecular weight Mn of the β-ferrandylene polymer obtained as described above is 10,000 to 100 from the viewpoint of increasing the viscosity and melt viscosity of the polymerization solution, moldability, strength of the molded optical disk substrate, and heat resistance. Ten thousand is preferable. The number average molecular weight Mn of the β-ferrandylene polymer used in the present invention can be adjusted to 20,000 to 500,000, 30,000 to 400,000, or 40,000 to 300,000. It can also be prepared, 50,000 to 250,000 can be prepared, 60,000 to 200,000 can be prepared, 70,000 to 150,000 can be prepared, 80,000 to 12 It can also be prepared in a million. If the molecular weight of the polymer is too large, the viscosity of the polymerization solution increases and the productivity of the polymer deteriorates, or the melt viscosity of the polymer increases and the moldability may deteriorate. On the other hand, if the molecular weight is too small, the strength of the optical disk substrate obtained using the polymer is lowered, and the glass transition temperature is less than 80 ° C., so that sufficient heat resistance may not be exhibited.

  The glass transition temperature Tg of the β-ferrandylene polymer is preferably about 80 to 350 ° C., more preferably 85 to 250 ° C., and more preferably 90 to 200 ° C. from the viewpoint of increasing heat resistance, moldability, and strength of the molded optical disk substrate. Is more preferable. The glass transition temperature Tg of the β-ferrandylene polymer used in the present invention can be adjusted to 80 ° C. or higher and 200 ° C. or lower, 85 ° C. or higher and 200 ° C. or lower, or 90 ° C. or higher and 200 ° C. or lower. It can be prepared at 95 ° C. or less, can be prepared at 95 ° C. or more and 200 ° C. or less, can be prepared at 100 ° C. or more and 200 ° C. or less, and can be prepared at 110 ° C. or more and 200 ° C. or less. In addition, it can be adjusted to 120 ° C. to 200 ° C., 125 ° C. to 200 ° C., and 130 ° C. to 200 ° C. When the glass transition temperature Tg is too high, the melt viscosity of the β-ferrandylene polymer becomes high and the moldability may be deteriorated. On the other hand, if the glass transition temperature Tg is too low, the heat-resistant use temperature of the molded optical disk substrate is lowered, which is not practical. Usually, the glass transition temperature Tg and heat resistance can be improved by increasing the molecular weight of the β-ferrandylene polymer and by hydrogenating the β-ferrandylene polymer.

In the present specification and claims, the number average molecular weight Mn of β-ferrandylene polymer is obtained according to the size exclusion chromatography method defined in JIS-K-0124-2002, and is a gel. It is obtained from the value of the differential refraction detector measured by permeation chromatography (GPC) and the calibration curve of standard polystyrene. The glass transition temperature Tg was measured according to the method defined in JIS-K-7121-1987 “Method for Measuring Plastic Transition Temperature”. More specifically, the glass transition temperature Tg (T _The temperature determined as _mg ) is the glass transition temperature Tg in the present specification and claims.

<Optical isomerism of β-ferrandrene>
The β-ferrandolene, which is a material of the β-ferrandylene polymer used in the present invention, is a mixture or a racemate of compounds that are optical isomers (enantiomers) represented by the following chemical formulas (I) and (II). Alternatively, only one of the optical isomers may be used. Chemically synthesized β-ferrandolene is usually a mixture or a racemate. When using β-ferrandolene consisting only of one of the optical isomers, it can be obtained by optical isomerization separation by using a method such as chromatography using a chiral column, diastereomer method using an optical resolving agent, etc. Materials may be used.

  The β-ferrandol polymer obtained by using the above-mentioned mixture or racemate of β-ferrandol as a material includes the following chemical formulas (I-1), (I-2), (II-1) and (II-2). Any one or more of monomer units (repeating units) represented by In each chemical formula, parentheses indicate a bond with an adjacent monomer unit that is polymerized (bonded).

  The β-ferrandylene polymer used in the present invention may have one, two, or three types of monomer units represented by the above chemical formulas. You may have, and you may have 4 types.

  In the β-ferrandylene polymer used in the present invention, when the mixture or racemate of the chemical formulas (I) and (II) is used as the material, the chemical formulas (I-1), (I-2), It is considered that β ferrandolene units represented by (II-1) and (II-2) are contained in a total of 50% by mass or more with respect to the total mass of the β ferrandolene polymer. The content is preferably 50 to 100% by mass, more preferably 70 to 100% by mass, further preferably 80 to 100% by mass, and most preferably 90 to 100% by mass.

<Hydrogenation to β-ferrandylene polymer>
Hydrogenation (hydrogenation) can be performed on the olefinic carbon-carbon double bond of the β-ferrandylene polymer used in the present invention. By performing hydrogenation, a polymer having further improved heat resistance can be obtained.

  As a method of adding hydrogen to the β-ferrandylene polymer, a known method of adding hydrogen to a conventional polymer can be applied. As the hydrogenation catalyst used in this case, catalysts generally used for hydrogenation reactions of olefins and aromatic compounds can be applied. For example, transition metals such as palladium, platinum, nickel, rhodium, ruthenium and the like are used as carbon. , Supported metal catalyst supported on a carrier such as alumina, silica, diatomaceous earth; homogeneous catalyst composed of organic transition metal compounds such as titanium, cobalt, nickel and organometallic compounds such as lithium, magnesium, aluminum, tin; Examples thereof include metal complex catalysts such as rhodium and ruthenium.

  Examples of the supported metal catalyst include nickel / silica, nickel / diatomaceous earth, nickel / alumina, palladium / carbon, palladium / silica, palladium / diatomaceous earth, palladium / alumina, platinum / silica, platinum / alumina, rhodium / Examples of the catalyst include silica, rhodium / alumina, ruthenium / silica, and ruthenium / alumina.

  Examples of the homogeneous catalyst include acetic acid / cobalt triethylaluminum, nickel trioctylate / triisobutylaluminum, nickel acetylacetonate / triisobutylaluminum, titanocene dichloride / n-butyllithium, zirconocene dichloride / sec-butyllithium, tetrabutoxy A combination of titanate and dimethylmagnesium can be mentioned.

  Examples of the metal complex catalyst include chlorotris (triphenylphosphine) rhodium, dihydridotetra (triphenylphosphine) ruthenium, hydrido (acetonitrile) tris (triphenylphosphine) ruthenium, carbonylchlorohydridotris (triphenylphosphine) ruthenium, Examples include carbonyl dihydridotris (triphenylphosphine) ruthenium.

Among the catalysts used in the hydrogenation reaction exemplified here, the supported metal catalyst is particularly preferable because it can be easily separated and recovered by filtration together with the polymerization catalyst after the hydrogenation reaction.
The said catalyst may be used individually by 1 type, and may use 2 or more types together.

  The reaction temperature at the time of hydrogenation can usually be carried out at -20 ° C to 250 ° C, preferably -10 ° C to 220 ° C, more preferably 0-200 ° C. If the reaction temperature is too high, the polymer may be thermally decomposed, and if it is too low, the reaction rate may be slow and the reaction may not be completed.

The hydrogen pressure at the time of hydrogenation can be usually 0.1-100 kgf / cm ² , preferably 0.5-70 kgf / cm ² , more preferably 1-50 kgf / cm ² . . If the hydrogen pressure is too low, the hydrogenation reaction is slow, and if it is too high, a high pressure reactor is required.

The solvent for the hydrogenation is not particularly limited as long as the polymer is dissolved and the catalyst is inert. From the viewpoint of the solubility and reactivity of the hydrogenated product of the polymer, examples include aliphatic hydrocarbons, halogenated hydrocarbons, and aromatic hydrocarbons. Specifically, aromatic hydrocarbon solvents such as benzene and toluene; aliphatic carbonization such as n-pentane, n-hexane, n-heptane, n-octane, cyclopentane, cyclohexane, methylcyclohexane, ethylcyclohexane and decalin Hydrogen solvents; ether solvents such as tetrahydrofuran and ethylene glycol dimethyl ether; methylene chloride, chloroform, 1,1-dichloroethane, 1,2-dichloroethane, n-propyl chloride, 1-chloro-n-butane, 2-chloro-n -Halogenated hydrocarbon solvents such as butane. Of these organic solvents, hydrocarbon solvents are particularly preferable from the viewpoints of solubility and reactivity.
The said organic solvent may be used individually by 1 type, and may use 2 or more types together.

  In the hydrogenation, it is also possible to carry out the hydrogenation reaction as it is without exchanging the solvent of the reaction solution after the polymerization reaction of β-ferrandrene is completed. When hydrogenation is performed without replacing the solvent in this way, waste liquid discharged from the production process is reduced, which is preferable from the viewpoint of reducing the environmental load.

  The reaction time of the hydrogenation can be usually performed for about 0.1 to 20 hours. As a measure of completion of the hydrogenation reaction, for example, among the olefinic carbon-carbon double bonds (unsaturated bonds) of the polymer before hydrogenation, preferably 70% or more, more preferably 80% or more, It is desirable to continue the hydrogenation until preferably 90% or more, particularly preferably 95% or more is saturated, most preferably 100% is saturated. By sufficiently hydrogenating the β-ferrandylene polymer, a polymer having excellent heat resistance and light resistance can be obtained.

As a method for obtaining the hydrogenation rate of the olefinic carbon-carbon double bond in the polymer before and after the hydrogenation, in general, iodine titration method, infrared spectroscopic measurement, nuclear magnetic resonance spectrum ( ¹ H-NMR spectrum) A method of calculating from an analysis value such as measurement is known.

In the present specification and claims, the hydrogenation ratio of the β-ferrandylene polymer to the olefinic carbon-carbon double bond is a nuclear magnetic resonance spectrum ( ¹ H-NMR spectrum) using deuterated chloroform as a solvent. It is calculated using the measured value. Specifically, the integrated value of the signal detected at δ = 5.0 to 6.0 ppm, that is, the integrated value of the signal derived from the proton of the olefinic carbon-carbon double bond, assuming that the proton of tetramethylsilane is 0 ppm. The ratio (A / B) between A and the integral value of the signal detected at 0.5 to 2.5 ppm, that is, the integral value B of the signal derived from the saturated hydrocarbon proton is calculated. This ratio decreases as the hydrogenation rate increases. By calculating the ratio before hydrogenation (A / B (before hydrogenation)) and the ratio after hydrogenation (A / B (after hydrogenation)), respectively, and substituting them into the following formula, hydrogenation The rate can be determined.

Hydrogenation rate (%) =
(Ratio (A / B (before hydrogenation))-ratio (A / B (after hydrogenation)) × 100 ÷ ratio (A / B (before hydrogenation))

The glass transition temperature Tg of the polymer obtained by hydrogenating the β-ferrandylene polymer is assumed to be used in an environment close to a heat source (for example, a light source that generates heat), or surface processing is easy. From the viewpoint of becoming, the higher one is preferable. From the viewpoint of reducing the influence of the heat of the light source, Tg is more preferably 100 ° C. or higher. The optical disk substrate according to the present invention can be subjected to known surface processing (surface treatment) in order to improve its chemical resistance, impart antistatic properties, or impart electrical conductivity. Since these surface treatments can be easily performed, the Tg of the hydrogenated β-ferrandylene polymer is preferably 120 ° C. or higher. When Tg exceeds about 200 ° C., the melt viscosity of the β-ferrandylene polymer increases, and the moldability may be deteriorated. On the other hand, if the Tg is less than 80 ° C., the heat resistant use temperature of the optical disk substrate is lowered, which is not preferable.
The method for measuring the glass transition temperature Tg of the hydrogenated β-ferrandylene polymer may be the same as the method for measuring the glass transition temperature Tg of the non-hydrogenated β-ferrandylene polymer.

The total light transmittance of the β-ferrandylene polymer used in the present invention is preferably as high as the properties usually required for its use, preferably 80% or more, more preferably 85% or more, and still more preferably 90% or more. . For example, when a flat test piece having a thickness of about 3.2 mm made only of β-ferrandrene polymer is measured, the total light transmittance is preferably 80% or more, more preferably 85% or more. 90% or more is more preferable, and 95% or more is most preferable.
Here, the total light transmittance is a value measured in accordance with JIS-K-7361: 1997 (ISO13468-1: 1996).

The light transmittance at a wavelength of 400 nm to 850 nm of the β-ferrandylene polymer used in the present invention is preferably as high as the properties usually required for its use, preferably 90% or more, more preferably 95% or more, 98 % Or more is more preferable. For example, when a flat test piece having a thickness of about 3.2 mm made only of β-ferrandylene polymer is measured, the light transmittance at an arbitrary wavelength in the wavelength range is preferably 90% or more, and 95% or more. It is more preferable that it is 98% or more.
Here, the light transmittance of the said wavelength is a numerical value measured using the spectrophotometer. Specifically, for example, the light transmittance (transmitted light intensity / percentage of incident light intensity) of the wavelength is measured every arbitrary wavelength interval of 1 to 20 nm in the wavelength range, and the arithmetic average of each measured value is calculated. By doing so, the light transmittance can be obtained.

The β-ferrandylene polymer used in the present invention preferably has a low water absorption rate from the viewpoint of dimensional stability. The water absorption of the β-ferrandylene polymer is 0.2 when the mass change of the test piece when the test piece is placed in an atmosphere of 60 ° C. and 90% RH (relative humidity) for 24 hours is measured as the saturated water absorption. % Or less is preferable, 0.1% or less is more preferable, and 0.05% or less is more preferable.
Here, the water absorption is a numerical value measured according to JIS-K-7209: 2000. At this time, as the test piece, the β-ferrandylene polymer formed into a sheet shape of 60 mm long × 60 mm wide × 1 mm thick can be used.

Since the specific gravity of the β-ferrandylene polymer used in the present invention is small, a light optical disk substrate can be obtained. The specific gravity of the β-ferrandylene polymer used in the present invention is 0.85 or more and less than 1.0, preferably 0.85 to 0.98.
It is usually difficult to obtain a β-ferrandylene polymer having a specific gravity of less than 0.85. Further, if the specific gravity is 1.0 or more, the object of weight reduction cannot be sufficiently achieved.
Here, the specific gravity is a numerical value measured according to A method of JIS-K-7112: 1999.

  In general, when the photoelastic coefficient of the resin constituting the molded article is large at a temperature equal to or higher than Tg, there is a problem that the optical distortion of the obtained molded article increases. Therefore, when trying to obtain a molded product with a small optical distortion, the range in which the molding conditions can be selected becomes narrow, and there is a problem that productivity is lowered.

  Accordingly, it is preferable that the β-ferrandylene polymer used in the present invention has a small photoelastic coefficient, and it is more preferable that the photoelastic coefficient is small even at a temperature equal to or higher than the glass transition temperature Tg. By using a β-ferrandylene polymer with low photoelasticity, an optical disk substrate with little optical distortion can be obtained.

A suitable photoelastic coefficient at a temperature equal to or higher than Tg (for example, Tg + 20 ° C.) of the β-ferrandylene polymer to be used cannot be generally specified depending on the use, but is −3000 × 10 ^{−13 to} 3000 × 10 ⁻¹³ cm ² / dyn. Is preferable, and −1000 × 1000 ^{−13 to} 1000 × 10 ⁻¹³ cm ² / dyn is more preferable. By having a photoelastic coefficient in this range, an optical plastic film with small optical distortion can be obtained with high productivity. Note that 1 dyn = 10 ⁻⁵ N.

  The bending elastic modulus of the β-ferrandylene polymer used in the present invention is preferably 2500 MPa or more, and more preferably 2700 MPa or more. When the bending elastic modulus is within this range, deformation due to bending can be suppressed and the thickness of the optical disk substrate can be reduced. Here, the flexural modulus is a numerical value measured by a method based on ASTM D790. At this time, as the test piece, for example, a product obtained by molding the β-ferrandylene polymer into a shape recommended by the ASTM D790 standard can be used.

  The refractive index nD (25 ° C.) of the β-ferrandylene polymer used in the present invention is preferably in the range of 1.450 to 1.600. When the refractive index is within this range, an optical disk substrate can be formed in the same manner as a conventional transparent resin (PMMA has a refractive index of 1.49 and PC has a refractive index of 1.59). Here, the said refractive index nD (25 degreeC) is a numerical value measured by the method based on JIS-K-7142. At this time, as the test piece, the β-ferrandylene polymer formed into a plate or film having a size recommended by the JIS standard can be used, for example.

<Optical disk substrate>
The optical disk substrate of the present invention is an optical disk substrate in which the above-described β-ferrandylene polymer is contained in an amount of 50 to 100% by mass with respect to the total mass of the optical disk substrate.
The β-ferrandylene polymer constituting the optical disk substrate has a specific gravity of 0.85 or more and less than 1.0, and a light transmittance of an arbitrary wavelength in the wavelength range of 400 nm to 850 nm is 90% or more.

  The content of the β-ferrandylene polymer contained in the optical disk substrate of the present invention may be 60 to 100% by mass or 70 to 100% by mass with respect to the total mass of the optical disk substrate. 80-100 mass% may be sufficient, 90-100 mass% may be sufficient, 95-100 mass% may be sufficient, and 98-100 mass% may be sufficient.

  In order to improve the mechanical strength and heat resistance of the optical disk substrate of the present invention, the mechanical strength and heat resistance of the β-ferrandylene polymer which is the main component of the optical disk substrate may be improved. From the viewpoint of improving the mechanical strength and heat resistance of the β-ferrandylene polymer, the preferred Tg is preferably 100 to 350 ° C, more preferably 100 to 250 ° C, and still more preferably 100 to 200 ° C. From the same viewpoint, the preferred number average molecular weight Mn of the β-ferrandylene polymer is preferably as large as possible, preferably 40,000 or more, more preferably 60,000 or more, still more preferably 80,000 or more, and even more preferably 100,000 or more. Preferably, 120,000 or more is particularly preferable, and 140,000 or more is most preferable. The upper limit of the number average molecular weight Mn is not particularly limited, but is usually preferably 800,000 or less, more preferably 600,000 or less, and still more preferably 400,000 or less, from the viewpoint of improving moldability and workability.

Further, from the same viewpoint as described above, the preferred weight average molecular weight Mw of the β-ferrandylene polymer is preferably as large as possible, preferably 50,000 or more, more preferably 70,000 or more, still more preferably 90,000 or more, and 110,000 or more. Even more preferred is 130,000 or more, most preferred is 150,000 or more. The upper limit of the weight average molecular weight Mw is not particularly limited, but is usually preferably 1 million or less, more preferably 800,000 or less, and still more preferably 600,000 or less from the viewpoint of improving moldability and workability. The weight average molecular weight can be calculated from measurement data obtained by the same method as the number average molecular weight.
From the same viewpoint as described above, the Mw / Mn of the β-ferrandylene polymer is preferably 1 to 25, more preferably 1.05 to 20, and still more preferably 1.1 to 10.

  The specific gravity of the optical disk substrate of the present invention is such that the above-described β-ferrandylene polymer constitutes 50 to 100% by mass of the total mass of the optical disk substrate, more preferably 70 to 100% by mass. Usually, it can be in the range of 0.85 to 1.0. Since the β-ferrandylene polymer has a lighter specific gravity than conventional acrylic resins, PET resins, polyvinyl chloride resins, etc., the optical disk substrate according to the present invention having the β-ferrandylene polymer as a main component is used for these conventional resins. It is more lightweight than the optical disk substrate made of.

  From the viewpoint of improving the heat resistance of the optical disk substrate of the present invention, it is preferable that at least a part of the olefinic carbon-carbon double bond of the β-ferrandylene polymer used in the present invention is hydrogenated.

  The total light transmittance of the optical disk substrate of the present invention is preferably as high as the properties usually required for its use, preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. For example, as an example of the optical disk substrate of the present invention, when a flat test piece having a thickness of about 1.0 mm is measured, the total light transmittance is preferably 80% or more, more preferably 85% or more. Preferably, it is more preferably 90% or more, and most preferably 95% or more. Here, the total light transmittance is a value measured in accordance with JIS-K-7361: 1997 (ISO13468-1: 1996).

The light transmittance of an arbitrary wavelength in the wavelength range of 400 nm to 850 nm of the optical disk substrate of the present invention is preferably as high as the properties usually required for its use, preferably 90% or more, more preferably 95% or more, 98% or more is more preferable. For example, as an example of the optical disk substrate of the present invention, when a flat test piece having a thickness of about 1.0 mm is measured, the light transmittance at an arbitrary wavelength in the wavelength range is preferably 90% or more, and 95% More preferably, it is more preferably 98% or more.
Here, the light transmittance of the said wavelength is a numerical value measured using the spectrophotometer similarly to the measuring method of the light transmittance of (beta) ferrandylene polymer mentioned above.

The water absorption rate of the optical disk substrate of the present invention is more preferably 70 to 100% by mass when the β-ferrandylene polymer constitutes 50 to 100% by mass of the total mass of the optical disk substrate. In this case, when the optical disk substrate is placed in an atmosphere of 60 ° C. and 90% RH (relative humidity) for 24 hours, the change in mass is measured as a saturated water absorption, preferably 0.2% or less, and 0.1% or less Is more preferable, and 0.05% or less is more preferable. Here, the water absorption is a numerical value measured according to JIS-K-7209: 2000.
Since β-ferrandylene polymer has lower water absorption than conventional acrylic resins, the optical disk substrate of the present invention having β-ferrandylene polymer as a main component is more dimensionally stable than conventional optical disk substrates made of acrylic resin. Excellent in properties.

  The photoelastic coefficient of the optical disk substrate of the present invention is such that, when the β-ferrandylene polymer described above constitutes 95 to 100% by mass of the total mass of the optical disk substrate, a suitable photoelasticity of the β-ferrandylene polymer described above. Can be equivalent to the coefficient.

  The bending elastic modulus of the optical disk substrate of the present invention is such that when the β-ferrandylene polymer described above constitutes 95 to 100% by mass of the total mass of the optical disk substrate, the above-described β-ferrandylene polymer is suitable for bending elasticity. Can be equal to the rate.

  The refractive index of the optical disk substrate of the present invention is such that when the β-ferrandylene polymer mentioned above constitutes 95 to 100% by mass of the total mass of the optical disk substrate, Can be equivalent.

  In the β-ferrandylene polymer for molding the optical disk substrate of the present invention, various known compounding agents may be used alone or in combination of two or more, if necessary, within the range not impairing the object of the present invention. Or may be mixed.

  The compounding agent is not particularly limited as long as it is usually used in the conventional resin industry. For example, an antioxidant, an ultraviolet absorber, a light stabilizer, a near infrared absorber, a colorant such as a dye or a pigment. , Lubricants, plasticizers (softening agents), antistatic agents, fluorescent brighteners, fillers and the like.

  Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, and the like. Among these antioxidants, phenolic antioxidants are preferable, and alkyl-substituted phenolic antioxidants are particularly preferable.

  Examples of the phenolic antioxidant include 2-t-butyl-6- (3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2,4-di-t- Acrylate compounds such as amyl-6- (1- (3,5-di-t-amyl-2-hydroxyphenyl) ethyl) phenyl acrylate; octadecyl-3- (3,5-di-t-butyl-4- Hydroxyphenyl) propionate, 2,2′-methylene-bis (4-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ′, 5′-di-) -Butyl-4'-hydroxyphenylpropionate) methane [i.e. pentaerythrimethyl-tetrakis (3- (3,5-di-t-butyl-4-hydroxyphenylpropionate)], triethylene glycol bis (3- Alkyl-substituted phenolic compounds such as (3-t-butyl-4-hydroxy-5-methylphenyl) propionate); 6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bisoctyl Thio-1,3,5-triazine, 4-bisoctylthio-1,3,5-triazine, 2-octylthio-4,6-bis- (3,5-di-t-butyl-4-oxyanilino)- Examples include triazine group-containing phenol compounds such as 1,3,5-triazine.

  Examples of the phosphorus antioxidant include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4- Di-t-butylphenyl) phosphite, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, etc. Monophosphite compounds; 4,4′-butylidene-bis (3-methyl-6-tert-butylphenyl-di-tridecylphosphite), 4,4′-isopropylidene-bis (phenyl-di-alkyl ( And diphosphite compounds such as C12 to C15) phosphite). Among these, monophosphite compounds are preferable, and tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite and the like are particularly preferable.

  Examples of the sulfur antioxidant include dilauryl 3,3-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3-thiodipropionate, lauryl stearyl 3,3-thio. Dipropionate, pentaerythritol-tetrakis- (β-lauryl-thiopropionate), 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane Etc.

  The said antioxidant can be used individually or in combination of 2 or more types, respectively. The blending amount of the antioxidant may be appropriately determined as long as the object of the present invention is not impaired, for example, about 0.001 to 5 parts by weight with respect to 100 parts by weight of the β-ferrandylene polymer, Preferably it can be used in the range of 0.01 to 1 part by weight.

  Examples of the ultraviolet absorber include 2- (2-hydroxy-5-methylphenyl) 2H-benzotriazole, 2- (3-tert-butyl-2-hydroxy-5-methylphenyl) -5-chloro-2H. -Benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -5-chloro-2H-benzotriazole, 2- (3,5-di-t-butyl-2-hydroxyphenyl) -2H-benzotriazole, 5-chloro-2- (3,5-di-t-butyl-2-hydroxyphenyl) -2H-benzotriazole, 2- (3,5-di-t-amyl-2-hydroxy Benzotriazole ultraviolet absorbers such as phenyl) -2H-benzotriazole; 4-t-butylphenyl-2-hydroxybenzoate, phenyl-2-hydroxybenzoate Zoate, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate, 2- (2H- Benzotriazol-2-yl) -4-methyl-6- (3,4,5,6-tetrahydrophthalimidylmethyl) phenol, 2- (2-hydroxy-5-t-octylphenyl) -2H-benzotriazole Benzoate ultraviolet absorbers such as 2- (2-hydroxy-4-octylphenyl) -2H-benzotriazole; 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxybenzophenone -5-sulfonic acid trihydrate, 2-hydroxy-4-octyloxybenzophenone, 4- Benzophenone ultraviolet rays such as decyloxy-2-hydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2,2 ′, 4,4′-tetrahydroxybenzophenone, 2,2′-dihydroxy-4,4′-dimethoxybenzophenone Absorber; acrylate ultraviolet absorber such as ethyl-2-cyano-3,3-diphenyl acrylate, 2′-ethylhexyl-2-cyano-3,3-diphenyl acrylate; [2,2′-thiobis (4-t -Octylphenolate)] A metal complex ultraviolet absorber such as 2-ethylhexylamine nickel can be used.

  Examples of the light stabilizer include 2,2,6,6-tetramethyl-4-piperidylbenzoate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, and bis (1,2, 2,6,6-pentamethyl-4-piperidyl) -2- (3,5-di-tert-butyl-4-hydroxybenzyl) -2-n-butylmalonate, 4- (3- (3,5- Di-t-butyl-4-hydroxyphenyl) propionyloxy) -1- (2- (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy) ethyl) -2,2,6 And hindered amine light stabilizers such as 1,6-tetramethylpiperidine.

  Examples of the near-infrared absorber include cyanine-based near-infrared absorbers; pyrylium-based near-infrared absorbers; squarylium-based near-infrared absorbers; croconium-based near-infrared absorbers; Dithiol metal complex near infrared absorbers; naphthoquinone near infrared absorbers; anthraquinone near infrared absorbers; indophenol near infrared absorbers; As commercially available near infrared absorbers, SIR-103, SIR-114, SIR-128, SIR-130, SIR-132, SIR-152, SIR-159, SIR-162 (above, Mitsui Toatsu Dye Co., Ltd.) Company-made), Kayasorb IR-750, Kayasorb IRG-002, Kayasorb IRG-003, Kayasorb IR-820B, Kayasorb IRG-022, Kayasorb IRG-023, Kayasorb CY-2, Kayasorb CY-2 , Manufactured by Nippon Kayaku Co., Ltd.).

  The dye is not particularly limited as long as it is uniformly dispersed or dissolved in the β-ferrandylene polymer to be used. For example, an oil-soluble dye (various C.I. Solvent dyes). Specific examples of the oil-soluble dye include, for example, “Color Index” published by The Society of Dyers and Colorists, Vol. 3. Various C.I. I. Solvent dyes may be mentioned.

  Among the pigments, organic pigments include, for example, diarylide pigments such as Pigment Red 38; azo lake pigments such as Pigment Red 48: 2, Pigment Red 53, and Pigment Red 57: 1; Pigment Red 144 and Pigment Red 166. Pigment Red 220, Pigment Red 221 and Pigment Red 248; condensed azo pigments such as Pigment Red 171, Pigment Red 175, Pigment Red 176, Pigment Red 185 and Pigment Red 208; Pigment Red 122 and the like Quinacridone pigments; perylene pigments such as Pigment Red 149, Pigment Red 178, and Pigment Red 179; and anthraquinone pigments such as Pigment Red 177. Examples of inorganic pigments include titanium oxide, carbon black, red pepper, chrome red, molybdenum red, resurge, and iron oxide.

  When the optical disk substrate of the present invention needs to be colored, any of the dyes and pigments can be used within the scope of the present invention. For example, in applications that require consideration of micro optical properties, coloring with dyes is preferred. In addition, the ultraviolet absorber may visually show a yellow to red color, and the near-infrared absorber may visually show a black color. Therefore, these light absorbers and the dyes and pigments are strictly used. There is no need to distinguish between them. Moreover, you may use combining these light absorption materials, the said dye, and a pigment.

Examples of the lubricant include organic compounds such as aliphatic alcohol esters, polyhydric alcohol esters, and partial esters, and inorganic fine particles.
Examples of the organic compound include glycerol monostearate, glycerol monolaurate, glycerol distearate, pentaerythritol monostearate, pentaerythritol distearate, pentaerythritol tristearate, and the like.
Examples of the inorganic fine particles include oxides, sulfides, hydroxides, nitrides, halides, carbonates, sulfates, acetates of Group 1, Group 2, Group 4, and Group 6-14 elements of the Periodic Table. Examples thereof include fine particles such as phosphates, phosphites, organic carboxylates, silicates, titanates, borates, and hydrates thereof, complex compounds centered on them, and natural compounds.

  Examples of the plasticizer include tricresyl phosphate, trixylenyl phosphate, triphenyl phosphate, triethylphenyl phosphate, diphenyl cresyl phosphate, monophenyl dicresyl phosphate, diphenyl monoxylenyl phosphate Phosphoric acid triester plasticizers such as monophenyldixylenyl phosphate, tributyl phosphate, triethyl phosphate; dimethyl phthalate, dibutyl phthalate, diheptyl phthalate, di-n-octyl phthalate, di-2 phthalate -Phthalic acid ester plasticizers such as ethylhexyl, diisononyl phthalate, octyldecyl phthalate, and butylbenzyl phthalate; fatty acid monobasic acid esters such as butyl oleate and glycerol monooleate System plasticizers; dihydric alcohol ester-based plasticizers; oxy ester plasticizer and the like. Among these, phosphate triester plasticizers are preferable, and tricresyl phosphate and trixylenyl phosphate are particularly preferable.

  Other specific examples of the plasticizer include squalane (C30H62, Mw = 422.8), liquid paraffin (white oil, ISO VG10, ISO VG15, ISO VG32, ISO VG68, ISO VG100 as defined in JIS-K-2231. ISO VG8 and ISO VG21), polyisobutene, hydrogenated polybutadiene, hydrogenated polyisoprene and the like. Among these, squalane, liquid paraffin, and polyisobutene are preferable.

  Examples of the antistatic agent include long-chain alkyl alcohols such as stearyl alcohol and behenyl alcohol, fatty acid esters of polyhydric alcohols such as glycerin monostearate and pentaerythritol monostearate, and stearyl alcohol and behenyl alcohol are particularly preferable.

  The said compounding agent can be used individually or in mixture of 2 or more types. The mixing ratio is appropriately selected as long as the object of the present invention is not impaired. The amount of each compounding agent is appropriately selected within a range that does not impair the object of the present invention. The amount of each compounding agent is usually 0. It is preferable to use in the range of about 001 to 5 parts by weight, preferably 0.01 to 1 part by weight.

  The β-ferrandylene polymer for molding the optical disk substrate according to the present invention can be blended with other polymer components as needed within the range not impairing the object of the present invention.

The shape of the optical disk substrate of the present invention is a disk shape (disk shape). The thickness is not particularly limited, and is preferably about 30 μm to 3000 μm, more preferably about 50 μm to 1000 μm, and further preferably about 70 μm to 300 μm. When these thicknesses are suitable, mechanical strength such as rigidity is sufficient, and a lightweight optical display substrate can be obtained.
The diameter of the optical disk substrate of the present invention is not particularly limited and can be appropriately adjusted according to the application. For example, an optical disk substrate having a diameter of about 10 mm to 200 mm can be given.

The thickness variation of the optical disk substrate of the present invention is preferably 3.0% or less of the thickness, more preferably 2.4% or less. When the variation in thickness is so small, the rotation accuracy of the optical disk of the present invention can be improved.
Here, as a method for measuring the film thickness, there are a radiation method (β-ray, γ-ray, χ-ray, fluorescent χ-ray, etc.), optical interference method, laser method, capacitance method, microwave method, contact method, and the like. However, it is not particularly limited. In the case of the contact method, it is preferable to conform to JIS-K-7130: 1999.

  The optical disk of the present invention can be obtained by forming a signal recording surface on at least one surface of the optical disk substrate of the present invention. Specific examples of such an optical disc include, for example, a CD, DVD, Blu-ray disc, video disc, write-once optical disc, rewritable optical disc, magneto-optical disc, etc., in which recording layers are laminated by a known method. Can be mentioned.

  The configuration of the optical disk substrate of the present invention can be used as a single-plate type optical disk in which a signal (information) recording surface composed of uneven pits and a functional film, which will be described later, is formed on at least a part of one surface of the optical disk substrate. Further, the two optical disk substrates constituting the single-plate optical disk can be used as a double-sided optical disk in which both surfaces are signal recording surfaces by being bonded via an adhesive layer. Signals recorded on these optical disks are usually read by irradiating with laser light. Although details are not described here, writing of signals (information) to the optical disc of the present invention can be performed by a known method.

  The ratio of the optical disk substrate in the optical disk of the present invention is not particularly limited, and can be configured to occupy, for example, 5 to 95% by mass with respect to the total mass of the optical disk.

<Optical disk substrate, optical disk manufacturing method>
The production (molding) method of the optical disk substrate of the present invention is not particularly limited, and examples thereof include a known injection molding method, hot press molding method, extrusion molding method, and cutting method. Of these production methods, an injection molding method, a hot press molding method, and an extrusion molding method are preferable from the viewpoint of increasing productivity.

  The method for producing an optical disk of the present invention is not particularly limited, and a known method for producing an optical disk using a conventional transparent resin can be applied. As an example, there is a method of forming concave and convex pits on which a predetermined signal (information) is recorded on one side of the optical disk substrate according to the first aspect of the present invention. As a first method for forming the concave and convex pits, a known ultraviolet curable resin or thermosetting resin is applied on the optical disk substrate by a method similar to the conventional method, and then a predetermined signal is recorded. There is a method in which a stamper having uneven pits is pressure-bonded and then the resin is cured by ultraviolet rays or heat. In addition, as a second method for forming the concave / convex pits, there is a method in which the concave / convex pits are formed on the substrate by directly pressing a stamper on the optical disk substrate.

A well-known functional film such as a reflective film, a recording film, or a dielectric film is formed on the uneven pits formed on the optical disk substrate as described above. The material constituting the functional coating is not particularly limited, and may be formed of an inorganic compound or an organic compound.
Examples of the constituent material of the reflective film include metals having high reflectivity such as Ni, Al, Au, and Pt.
Examples of the constituent material of the recording film include a Tb—Fe alloy, a Dy—Fe alloy, a Cd—Tb alloy, a Cd—Tb—Dy—Fe alloy, a Cd—C alloy, and a Tb—Fe—Co. rare earth such as system alloy - transition metal amorphous alloy, Ge-Te, Sb-Te-based, phase-change recording material such as _{in-Sb, Te-CS 2} , Pb-Te-Se, Te-C, TeO 2, Sb Write-once recording materials such as Se and Bi-Te, methine / polymethine series, quinones, naphthoquinones, anthraquinones, phthalocyanine series, dithiol series, tetrahydrocholines, dioxanes, dithiazines, thiabililiums, porphyrins, etc. And organic materials.
Examples of the constituent material of the dielectric film include compounds such as CdS, ZnS, ZnSe, SiO ₂ , Si, Si ₃ N ₄ , AlN, TiO ₂ , TaO ₂ , and MgF ₂ .
The method for forming the functional film is not particularly limited, and examples thereof include known film formation methods such as vapor deposition, sputtering, ion plating, dipping, and spin coating.

The optical disk substrate of the present invention is derived from petroleum such as polyolefin resin, acrylic resin, carbonate resin, etc. with respect to light transmittance, heat resistance, chemical resistance, water absorption, light resistance, photoelastic coefficient and mechanical strength. Compared to conventional resins, it has the same or better physical properties. In addition, since the specific gravity is lighter than many conventional resins, it is excellent in lightness.
In addition, the optical disk substrate made of a conventionally known β-pinene polymer has excellent lightness equivalent to that of the optical disk substrate of the present invention, but in the mechanical strength such as tensile strength, the β-ferrandylene polymer of the present invention is used. The constructed optical disk substrate is superior. As one of the factors, it can be considered that β-ferrandylene tends to form a polymer having a large number average molecular weight and easily forms an optical disk substrate having excellent mechanical strength.
Therefore, by using the aforementioned β-ferrandylene polymer, it is possible to produce a thin and lightweight optical disc having the same strength.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by these examples.

[Synthesis Example 1]
As a material for the optical disk substrate according to the present invention, a hydrogenated product of β-ferrandylene polymer was synthesized as follows.
[Production of β-ferrandylene polymer]
In a dried glass flask, 68 parts by weight of hexane (manufactured by Kanto Chemical Co., Inc.) was added and cooled to 0 ° C. A Lewis acid catalyst EtAlCl ₂ (ethylaluminum dichloride) (17% hexane solution, about 1 mol / L, manufactured by Tokyo Chemical Industry Co., Ltd.), 0.37 parts by weight, was dispersed well and obtained by chemical synthesis. Then, 5.1 parts by weight of β-ferrandolene (purity 83.3%) was slowly added dropwise. After 1 minute, 8 parts by weight of methanol was added to stop the polymerization reaction. After the reaction solution was transferred to a separatory funnel, 20 parts by weight of 1% sodium hydroxide solution was added and stirred well, and then the aqueous phase was separated and removed. Next, the organic solvent phase was slowly evaporated by an evaporator, and the reaction solution was concentrated. About 40 parts by weight of the concentrated reaction solution was slowly added dropwise to 240 parts by weight of methanol to reprecipitate the polymer. The resulting precipitate was separated from the solution by filtration and sufficiently dried to obtain a β-ferrandylene polymer. The reaction rate of the monomer during the reaction was 100%.

  The obtained β-ferrandylene polymer had a number average molecular weight of 105,300 and a glass transition temperature of 85 ° C.

[Hydrogenation]
In a pressure vessel sufficiently purged with nitrogen, 61 parts by weight of dehydrated hexane and 4 parts by weight of the obtained β-ferrandrene polymer were charged and sufficiently dissolved. Next, 10 parts by weight of a palladium / alumina catalyst (Pd: 5%, manufactured by Wako Pure Chemical Industries, Ltd.) was added, and a hydrogenation reaction was performed at 120 ° C. for 10 hours in an 8 MPa hydrogen atmosphere. The reaction solution is filtered using a filter made of Teflon (registered trademark) with a pore size of 1 μm, and after removing the catalyst, it is reprecipitated with methanol, the precipitate is sufficiently dried, and a hydrogenated product of β-ferrandylene polymer 4.5 parts by weight were obtained.

The hydrogenation proportion of the resulting β-phellandrene polymer was calculated by ^{1 H-NMR} spectrum measurement, it was 99.9%. The number average molecular weight of the polymer was 104,000, the glass transition temperature was 130 ° C., and the specific gravity was 0.93.

<Measurement method for polymer>

(Reaction yield)
By the method using o-dichlorobenzene as an internal standard, it was calculated from the reduction rate of the signal area of the signal of 5.5 to 6.5 ppm derived from the conjugated double bond of β-ferrandolene monomer.

(Number average molecular weight)
It was measured in terms of standard polystyrene. As the apparatus, an LC-20AD liquid feeding unit manufactured by Shimadzu Corporation and a RID-10 differential refractive index detector were used. Two columns, Shodex KF803, manufactured by Showa Denko KK were used. As the solvent, THF (40 ° C.) was used.

(Hydrogen addition rate)
Deuterated chloroform was used as the solvent. A 0 ppm correction was made with TMS. The H-NMR spectrum was measured using an NMR device manufactured by JEOL Ltd., JNM-ECX400 (400 MHz). The measurement was performed at room temperature.
The reduction rate of the peak of 5.0 to 6.0 ppm due to the unsaturated bond in the spectrum before hydrogenation was determined. At this time, the ratio A / B of the integral value A of the signal derived from the proton of the olefinic double bond of 5.0 to 6.0 ppm and the integral value B of the signal derived from the proton of the saturated hydrocarbon of 0.5 to 2.5 ppm is Using. The hydrogenation rate (%) was calculated by (A / B (Before) −A / B (After)) × 100 / A / B (Before).

(Total light transmittance)
A 1 mm-thick test piece made of the hydrogenated β-ferrandrene polymer prepared above was molded by the melt extrusion method, and the total light transmittance was measured using this as a measurement sample.
The total light transmittance was measured according to JIS-K-7361: 1997 (ISO13468-1: 1996). As a measuring device, a haze meter TC-H3DPK / II manufactured by Tokyo Denshoku Co., Ltd. was used.

(Light transmittance)
A 1 mm-thick test piece made of the hydrogenated β-ferrandylene polymer prepared above was formed by melt extrusion, and this was used as a measurement sample for light transmittance (transmitted light intensity / incident light intensity) of 400 to 850 nm. The percentage of each of the measured values was calculated and evaluated. As a measuring device, “UVmini-1240” manufactured by Shimadzu Corporation was used.
A: 90% or more B: Less than 90%

(Glass-transition temperature)
According to JIS-K-7121-1987 “Plastic Transition Temperature Measuring Method”, the glass transition temperature Tg of the hydrogenated β-ferrandylene polymer prepared above was measured using a differential calorimeter. As the apparatus, DSC-60 manufactured by Shimadzu Corporation was used.

(Water absorption rate)
A plate having a length of 140 mm, a width of 60 mm, and a thickness of 0.8 mm was press-molded using the β-ferrandylene polymer hydrogenated product prepared above. This plate was placed in an atmosphere of 60 ° C. and 90% RH for 10 days, the ratio of the mass increased from the initial mass was calculated by the following formula, and the water absorption rate was determined.
Water absorption rate (%) = increase in mass x 100 / initial mass

(Light resistance)
A 1.0 mm thick test piece made of the hydrogenated β-ferrandrene polymer prepared above was molded by melt extrusion, and the light resistance was evaluated using this as a measurement sample.
The test piece was placed in an ultraviolet exposure test apparatus and subjected to an accelerated exposure test for 100 hours, and the yellowing degree (ΔYI) before and after the YI (yellow index) test was measured. YI was measured according to ASTM-G53 and evaluated according to the following criteria.
ΔYI = (YI after 100 hours of UV exposure) − (YI before UV exposure)
A: ΔYI ≦ 1 ... Long-term light resistance is very good
B: 1 <ΔYI: long-term light resistance is poor

(Photoelastic coefficient)
A 0.2 mm-thick test piece made of the hydrogenated β-ferrandrene polymer prepared above was molded by melt extrusion, and the photoelastic coefficient was evaluated using this as a measurement sample.
The test piece (thickness: 200 μm) was annealed overnight at a temperature 20 ° C. lower than Tg, and then subjected to a tensile stress in the major axis direction at a temperature 20 ° C. higher than Tg. , Measured by an ellipsometer M220 (manufactured by JASCO Corporation), and the photoelastic coefficient was calculated from the amount of change in retardation with respect to stress. The calculated changes were classified according to the following criteria.
The absolute value of the change amount is A: less than 1000. The change amount is small and very good.
B: 1000 or more and less than 3000 ... The amount of change is within an allowable range, which is good.
C: 3000 or more: The amount of change is large and it is defective.
The unit is [× 10 ⁻¹³ cm ² / dyn].

(Flexural modulus)
In accordance with ASTM D790, the flexural modulus of each sample was measured. The results were judged according to the following criteria.
The thickness of the sample was 3.2 mm.
A: 2500 MPa or more: Good
B: Less than 2500 MPa ... poor

(Izod impact strength)
A 3.2 mm-thick tabular test piece made of the hydrogenated β-ferrandrene polymer produced above was molded, and the Izod impact strength was measured under notched conditions in accordance with ASTM D256. . A universal impact tester (manufactured by Yasuda Seiki Seisakusho) was used as a measuring device.

<Method for measuring physical properties of optical disk substrate>

(specific gravity)
The specific gravity of the optical disk substrate produced by the method described later was measured according to A method of JIS-K-7112: 1999, and evaluated according to the following criteria.
A: Specific gravity <1.0 ... Specific gravity is light and good.
B: 1.0 ≦ specific gravity <1.1 ... The specific gravity is heavy and it is defective.
C: 1.1 ≦ specific gravity: The specific gravity is heavier and poor.

(Moisture resistance)
The optical disk substrate produced by the method described later was subjected to a durability test for 1000 hours under the conditions of 80 ° C. and 90% RH, and the appearance change was visually observed. Judgment was made according to the following criteria.
A: There was no visual change and a good appearance was maintained.
B: Cloudiness or deformation was observed, and the appearance was deteriorated.

(Water absorption rate)
The optical disk substrate produced by the method described later was placed in an atmosphere of 60 ° C. and 90% RH for 10 days, the ratio of the increased mass from the initial mass was calculated by the following formula, and the water absorption rate was obtained.
Water absorption rate (%) = increase in mass x 100 / initial mass

<Manufacture of optical disk substrate>
[Example 1]
An optical disk substrate having a thickness of 1 mm made of the hydrogenated β-ferrandrene polymer obtained in Synthesis Example 1 was manufactured by an injection molding method. The evaluation results are shown in the following table.

[Comparative Example 1]
The pellets of the alicyclic polyolefin resin (ZEONOR 1060R manufactured by Nippon Zeon Co., Ltd., glass transition temperature: 102 ° C.) were dried at 80 ° C. for 4 hours using a hot air dryer. Next, using the same apparatus as in Example 1, the dried pellets were injection molded at 260 ° C. to form an optical disk substrate. Each physical property of the manufactured optical disk substrate was measured in the same manner as in Example 1. The evaluation results are shown in Table 1.

[Comparative Example 2]
The pellets of polymethyl methacrylate resin (Acrypet TF-8, manufactured by Mitsubishi Rayon Co., Ltd.) were dried at 85 ° C. for 6 hours using a hot cloth drier. Next, using the same apparatus as in Example 1, the dried pellets were injection molded at 220 ° C. to form an optical disk substrate. Each physical property of the manufactured optical disk substrate was measured in the same manner as in Example 1. The evaluation results are shown in Table 1.

[Comparative Example 3]
Polycarbonate resin (Mitsubishi Engineering Plastics, Iupilon H-3000)
Was injection molded at 280 ° C. to form an optical disk substrate. Each physical property of the manufactured optical disk substrate was measured in the same manner as in Example 1. The evaluation results are shown in Table 1.

  From the above results, it is clear that the optical disk substrate of Example 1 is an optical disk substrate having high light transmittance, heat resistance and light resistance, low water absorption, and excellent photoelasticity and lightness. It is understood that the optical disk substrate of Example 1 has an excellent balance of physical properties as compared with the optical disk substrates of Comparative Examples 1 to 3, and is advantageous in the use of the optical disk substrate.

  The configurations and combinations thereof in the embodiments described above are examples, and the addition, omission, replacement, and other modifications of the configurations can be made without departing from the spirit of the present invention. Further, the present invention is not limited by each embodiment, and is limited only by the scope of the claims.

  The present invention can be widely used as recording media for music, movies, video games, personal computer software, and the like.

Claims (8)

An optical disk substrate,
A β-ferrandylene polymer having a specific gravity of 0.85 or more and less than 1.0 and a transmittance of light having a wavelength of 400 nm to 850 nm of 90% or more is 50 to 100 based on the total mass of the optical disk substrate. An optical disk substrate comprising: mass%. 2. The optical disk substrate according to claim 1, wherein the β-ferrandlene polymer is formed by polymerizing at least one of β-ferrandolene represented by the following chemical formulas (I) and (II).

The β ferrandylene polymer contains a total of 50 mass% or more of β ferrandylene units represented by the following chemical formulas (I-1), (I-2), (II-1) and (II-2). The optical disk substrate according to claim 1, wherein the optical disk substrate is provided.

The optical disk substrate according to any one of claims 1 to 3, wherein the β-ferrandylene polymer has a number average molecular weight Mn of 40,000 or more. The optical disk substrate according to any one of claims 1 to 4, wherein at least a part of the olefinic carbon-carbon double bond of the β-ferrandylene polymer is hydrogenated. 6. The optical disk substrate according to claim 5, wherein a hydrogenation rate of the β-ferrandylene polymer is 70% or more. In the accelerated exposure test for 100 hours in accordance with ASTM-G53 on the plate having a thickness of 1.0 mm, the β-ferrandrene polymer has a yellowing degree (ΔYI) before and after the YI (yellow index) test. The optical disk substrate according to claim 1, wherein the optical disk substrate has a characteristic that is 1.0 or less. An optical disc comprising the optical disc substrate according to claim 1, wherein a signal recording surface is formed on at least one side of the optical disc substrate.