JP2002025108A - Optical disk substrate consisting of alicyclic polyolefin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk substrate having a high light transmittance, little haze, low water absorption and a low index of double refraction. SOLUTION: The optical disk substrate consists of an alicyclic polyolefin obtained by hydrogenating an aromatic polyolefin in the presence of a hydrogenation catalyst and satisfying the following conditions (1)-(4); (1) the rate of hydrogenation of aromatic rings is 90-99.5%, (2) the alicyclic polyolefin does not show a peak and does not substantially show a signal in the range of 6.3-6.8 ppm in its IH-NMR spectrum measured in heavy chloroform at room temperature, (3) the reduction viscosity (in toluene, 0.5g/dl, 30 deg.C) is >=0.2 and (4) the thermal deformation temperature is >=80 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for an optical disk comprising an alicyclic transparent polyolefin excellent in transparency, heat resistance and moldability.

[0002]

2. Description of the Related Art Plastics used for optical materials such as optical disk substrates and optical lenses include, in addition to transparency, optical isotropy (low birefringence), dimensional stability, weather resistance, thermal stability, etc. Various characteristics are required. Conventionally, polycarbonate or polymethyl methacrylate has been mainly used for these optical applications.However, polycarbonate has a large intrinsic birefringence and tends to cause optical anisotropy in molded products, and polymethyl methacrylate has a high water absorption. Is extremely high, so that dimensional stability is poor and heat resistance is low. Currently, polycarbonate is used for the optical disk substrate, but in recent years, the recording density has been increased, as represented by the increase in the capacity of a magneto-optical recording disk (MOD), the development of a digital versatile disk, and the development of a blue laser. With the progress of the above, there is a growing concern that the size of the birefringence of such a polycarbonate and the warpage of the disk due to moisture absorption will occur.

[0003] Under these circumstances, alicyclic polyolefin resins called amorphous polyolefins have recently been actively developed as substitutes for polycarbonate. As an example of these, hydrogenated polystyrene having a polyvinylcyclohexane structure by hydrogenating an aromatic ring of polystyrene by hydrogenation has been proposed (for example, Japanese Patent Publication No. 7-1140).
No. 30). Such a resin has a great advantage that it can be produced at a lower cost than other amorphous polyolefins. In order to improve the toughness of hydrogenated polystyrene, a styrene-conjugated diene block copolymer obtained by block copolymerizing styrene with conjugated diene such as isoprene and butadiene to introduce a rubber component was used for optical disc substrates and other products. There are also reports of examples of use for optical applications (Japanese Patent No. 2730053, Patent No. 27
No. 25402). Originally, in order to maintain high transparency of these hydrogenated styrene-based aromatic hydrocarbon polymers, it is preferable to completely hydrogenate the hydrogenated styrene-based aromatic hydrocarbon polymers by 100%. However, since the hydrogenation is rapidly delayed as the reaction proceeds, in consideration of the operating costs, the reaction must be stopped before the hydrogenation reaction is completed to 100% in industrial practice. The incompletely hydrogenated styrene-based aromatic hydrocarbon polymerization thus obtained often has a low transparency due to a high haze value, and is problematic for use as an optical disk substrate. .

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an excellent optical disk substrate having high light transmittance, low haze, low water absorption, and low birefringence.

[0005]

In view of the above prior art, the present inventors aimed at improving the above-mentioned drawbacks of an optical resin useful as an optical disk substrate, and in particular, aimed at improving the aromatic resin having a radial structure. The present inventors have focused on alicyclic polyolefins obtained by hydrogenating aromatic polyolefins and have conducted intensive studies on improving transparency, and as a result, have completed the present invention. That is, even when the hydrogenation reaction is 100% or less, a signal having an apex peak in a region of 6.3 to 6.8 ppm in a ¹ H-NMR spectrum measured in deuterated chloroform at room temperature is not substantially exhibited. It has been found that an alicyclic polyolefin having a radial structure has high transparency.

That is, the present invention is obtained by hydrogenating an aromatic polyolefin in the presence of a hydrogenation catalyst.
(4) (1) Aromatic hydrogenation rate is 90 to 99.5% (2) In a ¹ H-NMR spectrum measured at room temperature in deuterated chloroform, a peak peak is substantially present in a region of 6.3 to 6.8 ppm. (3) Reduced viscosity (0.5 g / dl in toluene, 30 ° C.)
) Is 0.2 or more. (4) An optical disk substrate made of an alicyclic polyolefin satisfying a heat distortion temperature of 80 ° C. or more.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The aromatic polyolefin in the present invention refers to an aromatic polyolefin, an aromatic olefin-conjugated diene copolymer, and a blend of both.

[0008] The aromatic polyolefin is a polymer of an aromatic olefin. Examples of the aromatic olefin include styrene, α-methylstyrene, 4-methylstyrene,
-Methylstyrene, vinylnaphthalene and the like. Of these, styrene is particularly preferred in terms of price. These may be used alone or in combination of two or more. The aromatic polyolefin can be synthesized from these aromatic olefins by a conventionally known method such as radical polymerization, anionic polymerization, or cationic polymerization. In the aromatic olefin-conjugated diene copolymer, examples of the conjugated diene include isoprene, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, and 1,3-butadiene.
Examples include pentadiene and 1,3-hexadiene. Among these, isoprene and 1,3-butadiene are preferred from the viewpoint of polymerization activity and economy. These may be used alone or in combination of two or more. The proportion of the conjugated diene component in the copolymer is preferably in the range of 1 to 30% by weight. From the viewpoint of improving mechanical properties such as impact resistance, it is better to have as many conjugated diene components as possible, but too much conjugated diene tends to cause aggregation, crystallization, lower transparency, and also lower heat resistance. Not preferred. If the conjugated diene component is less than 1% by weight, the effect of improving toughness cannot be obtained, which is not preferable. More preferably, the conjugated diene component is 2 to 25% by weight.

Examples of the type of the copolymer include a random copolymer, a complete block copolymer, and a tapered copolymer. The random copolymer is a copolymer in which an aromatic olefin component and a conjugated diene component are randomly bonded. The complete block copolymer is a copolymer of an aromatic olefin and a conjugated diene having a block structure. The tapered copolymer is a copolymer having a structure in which the copolymerization ratio of an aromatic olefin and a conjugated diene changes intermittently. Among them, a perfect block copolymer and a taper copolymer are preferable in consideration of impact resistance, heat resistance and the like.

The aromatic olefin-conjugated diene copolymer can be synthesized using an aromatic olefin and a conjugated diene as monomers using a conventionally known method such as anionic polymerization, cationic polymerization, or radical polymerization. It is preferable to use an anionic polymerization technique because the state of copolymerization can be strictly controlled.

In such a synthesis method, the polymerization reaction is usually carried out using a hydrocarbon solvent. Specifically, pentane, hexane, heptane, octane, aliphatic hydrocarbons such as decane, cyclopentane, cyclohexane, methylcyclohexane, alicyclic hydrocarbons such as cyclooctane, aromatic hydrocarbons such as benzene, toluene, xylene, etc. Can be mentioned. Among these hydrocarbon solvents, cyclohexane or methylcyclohexane is preferably used in terms of solubility and reactivity.

In addition to the above-mentioned hydrocarbon solvents, a polar solvent may be used for the purpose of controlling the polymerization reaction, controlling the microstructure of the conjugated diene portion, and the like. Examples of such polar solvents include ethers such as tetrahydrofuran, dioxane, diethylene glycol dimethyl ether, diethyl ether, methyl ethyl ether, and methyl tert-butyl ether; amines such as triethylamine and tetraethylethylene diamine; and phosphines.

As the anionic polymerization initiator used in the anionic polymerization, an organic lithium compound is generally used, and specifically, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium,
c-butyllithium, tert-butyllithium and the like. Among these, n-butyllithium or sec-
Butyl lithium is preferably used. When an organic lithium compound is used, the polymerization temperature is usually -20 ° C to 1 ° C.
20 ° C, preferably in the range of 10 ° C to 100 ° C. If the reaction temperature is too low, the polymerization rate will be slow, and if the reaction temperature is too high, the organolithium compound will be crushed. The polymerization must be performed under an inert atmosphere such as nitrogen or argon in order to prevent deactivation of the catalyst and the active polymer terminal during the polymerization. Although the polymerization reaction depends on the concentration and type of the initiator used, it is usually completed within several minutes to several hours, and a copolymer can be obtained quantitatively almost according to the charged monomer ratio.

The structure of the copolymer can be controlled by a conventionally known method such as a method of adding an aromatic olefin or a conjugated diene as a monomer to a polymerization solution, selection of a solvent, and the like. For example, in the case of styrene-isoprene-styrene-triblock copolymer, styrene is first polymerized by anionic polymerization in an aliphatic hydrocarbon solvent, and isoprene is introduced into the reaction system when styrene is almost completely consumed. After the isoprene has been almost completely consumed, styrene can be introduced again to cause a reaction.

The aromatic polyolefin to be subjected to the hydrogenation reaction mainly has a radial structure, and an aromatic polyolefin having at least 70% by weight of a radial structure is preferred. Here, the radial structure refers to a structure having a core and a branched chain extending linearly from the core. Therefore, the aromatic polyolefin having a radial structure is a star polymer. The number of branched chains extending from the core is at least three or more, depending on the type of the applied core. Of course, it is theoretically possible to obtain a star-shaped polymer having a larger number of branched chains by using a polyfunctional coupling agent as the core, but synthesis generally becomes more difficult as the number of branched chains increases. Considering such a synthetic surface from an industrial viewpoint, the aromatic polyolefin having a radial structure is preferably a star polymer having three or four branches, and more preferably a four-branch. These may be a mixture of three branches and four branches. Further, it may be inevitable that a low-molecular-weight one-branched component is generated in the synthesis, and a small amount of one-branched component may be contained. The content of the one branch component is 30% by weight.
Or less, and more preferably 25% by weight or less. If the amount of one branch component is 30% by weight or more, the fluidity of the resin increases but the molded product becomes brittle.

The production method of the radial type aromatic polyolefin is not particularly limited. For example, an aromatic polyolefin whose terminal is in an active state is synthesized by anionic polymerization.
It can be synthesized by adding a coupling agent thereto and coupling the polymers. As the coupling agent used here, tetrachlorosilane, methyltrichlorosilane, phenyltrichlorosilane,
1,2-bis (trichlorosilyl) ethane, 1,2-bis (trichlorosilyl) hexane, 1,2-bis (trichlorosilyl) methane, 1,2-bis (trichlorosilyl) octane, hexachlorodisilane, hexachlorodisiloxane Such as chlorosilanes, tetramethoxysilane, tetraethoxysilane, tetraphenoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, propyltrimethoxysilane, phenyltrimethoxysilane,
Methyltriethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, phenyltriethoxysilane, bis (trimethoxysilyl) methane, bis (trimethoxysilyl) ethane, hexamethoxydisiloxane, bis (triethoxysilyl) methane, bis Alkoxysilanes such as (triethoxysilyl) ethane and hexaethoxydisiloxane, dimethyl oxalate, dimethyl malonate, dimethyl succinate, dimethyl glutarate, dimethyl adipate, dimethyl phthalate, dimethyl isophthalate, dimethyl terephthalate, etc. Esters,
Examples include olefins such as divinylbenzene. Among these, alkoxysilanes are preferred in terms of high coupling efficiency and easy handling. The coupling reaction is usually carried out at -20 ° C to 120 ° C, preferably at 10 ° C.
C. to 100.degree. If the reaction temperature is too low, the coupling rate will be low, and if the polymerization temperature is too high, the active terminal will be crushed. The coupling reaction is usually completed within several minutes to several hours, depending on the type of the coupling agent used.

In the present invention, the aromatic polyolefin is hydrogenated in the presence of a hydrogenation catalyst to obtain an alicyclic polyolefin. Here, hydrogenation refers to hydrogenation of an aromatic ring and an unsaturated double bond between carbon atoms contained in the aromatic polyolefin. The hydrogenation catalyst used here is a solid catalyst capable of hydrogenating such an aromatic ring and an unsaturated double bond between carbon atoms, for example, a noble metal such as nickel, palladium, platinum, cobalt, ruthenium, and rhodium or an oxide thereof, Examples include solid catalysts in which compounds such as salts and complexes are supported on a porous carrier such as carbon, alumina, silica, and silica-alumina diatomaceous earth. Among them, those in which nickel, palladium, and platinum are supported on alumina, silica, and silica-alumina diatomaceous earth are preferably used because of their high reactivity. Such a hydrogenation catalyst is used in an amount of 0.5 to 40% by weight, preferably 1.0 to 30% by weight, based on the aromatic polyolefin, depending on its catalytic activity.

The hydrogenation reaction is usually carried out in the presence of a solvent under a hydrogen pressure of 30 to 250 kgf / cm ² (2.9 MPa to 24.5).
MPa) at a reaction temperature of 70 to 250 ° C.
If the reaction temperature is too low, the reaction does not easily proceed, and if the reaction temperature is too high, the molecular weight tends to decrease due to molecular chain breakage, which is not preferable. In order to prevent a decrease in molecular weight due to molecular chain breakage and promote the reaction smoothly, the hydrogenation reaction is carried out at an appropriate temperature and hydrogen pressure appropriately determined by the type and concentration of the catalyst used, the solution concentration of the copolymer, the molecular weight, etc. Is preferably performed.

As the solvent used in the hydrogenation reaction, it is preferable to select a solvent that does not poison the catalyst of the hydrogenation catalyst, and it is preferable to use a saturated aliphatic hydrocarbon such as cyclohexane and methylcyclohexane used as a solvent in the polymerization reaction. Can be listed. In addition, a polar solvent such as ethers such as tetrahydrofuran, dioxane, and methyl t-butyl ether, an ester, and an alcohol are dissolved in the polymer to dissolve the polymer for the purpose of increasing the activity of the reaction or suppressing a decrease in the molecular weight due to molecular chain cleavage. It may be added to the above-mentioned solvent within a range that does not hinder the property. In the present invention, it is preferable to carry out hydrogenation without isolating the copolymer in a solution state after the polymerization and the coupling reaction, and therefore, the solvent as it is after the polymerization reaction or as a solvent to which a necessary polar solvent is further added. A method of performing a hydrogenation reaction in a system is exemplified.

In the present invention, it is preferable to carry out the hydrogenation reaction in the above solvent system at a polymer concentration of 3 to 50% by weight, preferably 5 to 30% by weight. If the concentration of the polymer is less than 3% by weight, it is not preferable from the viewpoint of productivity and economy, and if it exceeds 50% by weight, the solution viscosity becomes too high, which is not preferable from the viewpoint of handling and reactivity.

The alicyclic polyolefin in the present invention is obtained by hydrogenating an aromatic polyolefin having a radial structure, and has the following (1) to (4) (1) an aromatic ring hydrogenation rate of 90 to 90: (2) In a ¹ H-NMR spectrum measured in deuterated chloroform at room temperature, a peak peak is not substantially observed in a region of 6.3 to 6.8 ppm (3) Reduced viscosity (in toluene 0.5 g / dl, 30 ° C
) Is 0.2 or more. (4) The heat distortion temperature is 80 ° C or more.

The hydrogenation rate of the aromatic ring refers to the hydrogenation rate of the aromatic ring contained in the aromatic polyolefin as the raw material. Derived by comparing ¹ H-NMR spectra of polyolefins. If the aromatic ring hydrogenation rate is lower than 90%, the transparency is significantly reduced, which is inconvenient as an optical disk substrate. If the degree of hydrogenation is higher than 99.5%, the transparency is satisfactory, but the reaction takes time, and the decomposition reaction may proceed to cause a decrease in the molecular weight. The aromatic ring hydrogenation rate is preferably 93 to 99.5%, more preferably 96 to 99.5%. When the aromatic polyolefin as a raw material is a copolymer of an aromatic olefin and a conjugated diene, it contains an unsaturated double bond between carbon atoms in addition to the aromatic ring. Since the double bond is much more easily hydrogenated than the aromatic ring, it can be considered that the hydrogenation is complete when the hydrogenation ratio of the aromatic ring is 90% or more.

The alicyclic polyolefin of the present invention does not substantially show a signal having an apex peak in a chemical shift range of 6.3 to 6.8 ppm in a ¹ H-NMR spectrum measured in deuterated chloroform at room temperature. . The fact that the peak peak is not substantially exhibited in the region of 6.3 to 6.8 ppm of chemical shift means that the sum of the integrated intensities of the signals including the peak peak in the region of 6.3 to 6.8 ppm is 0.0.
It means that it is 0.5% or less with respect to the total integrated intensity of peaks existing from ppm to 2.0 ppm. 0.5
%, The light transmittance is reduced even in a resin having a hydrogenation ratio of, for example, 96%, and the
The light transmittance in nm is greatly reduced to 40%. In addition, the peak resulting from 0.0 ppm to 2.0 ppm is a peak of an alicyclic polyolefin. 6.3 to 6.8
The signals present in the ppm range are assigned to unhydrogenated aromatic olefin chains spanning about 10 or more long chains (N. Kato et al., Analytical Science, 7 (suppl).
ement), 1605 (1991)). An alicyclic polyolefin that shows a signal having a peak peak in such a region tends to have significantly lower transparency even when the above-mentioned aromatic ring hydrogenation ratio is high. Generally, in the case of a hydrogenation reaction of a polymer using a homogeneous catalyst, the hydrogenation reaction proceeds randomly. Therefore,
When the degree of hydrogenation is as high as 90% or more, it is unlikely that the chain of the unhydrogenated aromatic olefin extends over a long chain. on the other hand,
It is known that when a solid catalyst is used, the hydrogenation reaction does not occur randomly and the polymer tends to be hydrogenated one molecule at a time (FSBates, J. Am. Chem. Soc, 110, 3).
542 (1988)). Regarding the hydrogenation reaction of the aromatic polyolefin in the present invention, the aromatic polyolefin tends to be hydrogenated one molecule at a time. As a result, even if the aromatic ring hydrogenation rate is high, unhydrogenated aromatic It is quite possible that the chain of the system olefin remains.

The above hydrogenation rate and the chain length of the unhydrogenated aromatic ring
Factors governing the reaction are the type of solid catalyst,
Medium, reaction temperature, reaction time, hydrogen pressure, stirring speed
Which reaction conditions, polymer structure such as linear type and radial type
Manufacturing, batch, and continuous reaction methods
Can be. Especially for radial type polymers, even if the hydrogenation rate is high,
¹A field showing the above-mentioned signal in the H-NMR spectrum
The hydrogenation rate and the signal strength as in the present invention.
Transparency is high by stipulating that no
A low haze polymer is obtained.

The alicyclic polyolefin of the present invention thus obtained has a tendency that a part of the polymer chain is broken by the hydrogenation reaction, and that the proportion of the one-branched component in the alicyclic polyolefin increases. is there. In the present invention, the radial structure in the alicyclic polyolefin is preferably 50% by weight or more, and the ratio of the one-branch component is preferably 50% by weight or less.

It is also necessary to grasp the reduced viscosity measured in a dilute solution as an index of the molecular weight. In the present invention, in a toluene solution having a concentration of 0.5 g / dL, 30 ° C.
When expressed in terms of the reduced viscosity η _sp / _c measured in the above, it is 0.2 or more, preferably 0.2 to 10 dL / g, more preferably 0.3 to 3 dL / g. If it is less than 0.2 dL / g, the mechanical strength of the molded product is insufficient. Also 10dL
If it is larger than / g, the moldability during molding tends to deteriorate. The molecular weight of the alicyclic polyolefin is determined by considering the mechanical strength of the molded product and the moldability during molding.
Number average molecular weight (Mn) in terms of polystyrene measured by PC (gel permeation chromatography)
And preferably in the range of 20,000 to 1,000,000, more preferably 30,000 to 800,000.
0, more preferably 30,000 to 50
It is in the range of 000. Number average molecular weight is 20,
If it is lower than 000, the mechanical strength is insufficient, and 1,000,000
If it is higher than 00, the melt viscosity is too high and molding becomes difficult, which is not preferable.

The alicyclic polyolefin used in the present invention has a heat distortion temperature (HDT) of 80 ° C. or higher, preferably 100 ° C. or higher, in which the land-groove structure and pits of the optical disk must be kept stable. There is.
One of the reasons for this is that road information is recorded on an optical disk substrate due to the rapid spread of car navigation systems in recent years. However, since the temperature inside a car may rise to a high temperature of about 80 ° C., at least this temperature is required. It is necessary to have the above heat deformation temperature.

The light transmittance of the alicyclic polyolefin in the present invention is desirably 85% or more.
Here, the light transmittance is a value obtained by measuring the total light transmittance of a molded plate having a thickness of 2 mm in accordance with JIS K7105-1981 (measurement method A). When the light transmittance is less than 85%,
Since light is absorbed in the resin, it is not suitable as an optical disk substrate.

The haze of the alicyclic polyolefin in the present invention is desirably 5% or less. Here, the haze is a value obtained by measuring the haze of a molded plate having a thickness of 2 mm according to JISK7105. If the haze is larger than 5%, the light is scattered, so that it is not suitable as an optical disk substrate.

After the completion of the hydrogenation reaction, the catalyst can be removed by a known post-treatment method such as centrifugation or filtration. In the present invention used for optical material applications, the residual catalytic metal component in the resin must be as small as possible, and the amount of the residual catalytic metal is preferably 10 ppm or less, more preferably 1 ppm or less. From the polymer solution from which the hydrogenation catalyst has been removed, the target hydrogenated copolymer can be obtained by a method such as evaporation of the solvent, stripping or reprecipitation.

In the case of high-density recording of an optical disk, the requirement for transferability of a stamper shape becomes more and more severe as in the case of a DVD. In addition, a single disk substrate itself can be reduced from 1.2 mm of a conventional CD to 0.6 mm of a DVD. It is shifting to something thinner as it goes to things. The optical disk substrate of the present invention has a thickness of 1.2 mm or less and can be used in a wide variety of optical disk fields. The optical disk substrate of the present invention can be manufactured using optical disk molding equipment such as a conventionally known injection compression molding machine. In the injection compression molding method for an optical disk substrate, molding conditions greatly depend on the substrate thickness and the recording density, and need to be optimized according to the material used. The melting temperature during molding largely depends on the glass transition temperature of the alicyclic polyolefin (glass transition temperature + 150), although it largely depends on the degree of polymerization of the resin material used.
C .- (glass transition temperature + 210) .degree. C. is preferred. If the melting temperature is lower than (glass transition temperature + 150) ° C,
Since the melt viscosity of the resin is too high, good transferability cannot be realized. In the case of molding at a resin temperature of (glass transition temperature + 210) ° C. or higher, thermal degradation during melting is so severe that the toughness is insufficient, and there is a possibility that the resin may be broken at the time of removal from the mold. Normally, hindered phenol-based stabilizers are severely thermally degraded during melting, and therefore it is preferable to use a resin containing a hindered phenol group-containing acrylate compound or a benzofuranone-based stabilizer as a heat stabilizer.

The mold temperature during molding is preferably in the range of (glass transition temperature -40 ° C.) to (glass transition temperature -10 ° C.) of the alicyclic polyolefin used. If the mold temperature is lower than (glass transition temperature −40 ° C.), good transfer cannot be achieved with a high-density stamper. When the mold temperature is higher than (glass transition temperature −10 ° C.), the transferability itself is improved, but the temperature is too close to the glass transition temperature of the polymer. The mold temperature is selected within a range that satisfies the required transferability.

The optical disk substrate of the present invention is provided with a recording layer, a reflective layer, a protective layer, and the like according to the purpose, and then bonded as necessary to be used as an optical disk.

[0034]

According to the present invention, the transparency is extremely high,
In addition, since an aliphatic polyolefin having excellent optical isotropy, dimensional stability, and heat resistance is used, an optical disk substrate having good transparency can be provided.

[0035]

The embodiments of the present invention will be described below with reference to examples, but these examples do not limit the present invention.

Cyclohexane, methyl t-butyl ether (solvent), styrene and isoprene were all purified by distillation and sufficiently dried.

N-butyllithium and sec-butyllithium were supplied by Kanto Chemical Co., Ltd. at a concentration of 1.57 M, respectively.
A 1.00 M n-hexane solution was purchased and used as it was.

Tetramethoxysilane was purchased from Shin-Etsu Chemical Co., Ltd., and bis (trimethoxysilyl) ethane was purchased from Aldrich, each having a concentration of 3.0% by weight.
Was prepared, and molecular sieve 4A was put into the solution and sufficiently dehydrated.

The Ni / silica-alumina catalyst (Ni loading 65% by weight) and the Pd / alumina catalyst (Pd loading 1% by weight) were purchased from Aldrich and used as they were.

Various physical property measurements performed in Examples and Reference Examples were performed by the following methods. Heat distortion temperature (HDT): Performed according to JIS K7207. Specimen shape: width 4.0mm, height 12mm, length 110mm, load 181.3 (N
/ cm ² ) Reduced viscosity: 30% of a toluene solution having a concentration of 0.5 g / dL
The reduced viscosity η _sp / _c at ° C. was measured.

Number average molecular weight, degree of branching: Gel permeation chromatography (GPC, S by Showa Denko KK)
With THF system as a solvent, the molecular weight and the degree of branching in terms of polystyrene were measured by a H.O.D. System-11).

Hydrogenation rate: JEOL JNM-A-400
It was quantified by ¹ H-NMR measurement using a nuclear magnetic resonance absorption apparatus.

Total light transmittance and haze: Measured using an automatic digital haze meter UDH-20D manufactured by Nippon Denshoku Industries Co., Ltd.

Disc molding: After synthesizing such an alicyclic polyolefin and providing a recording layer, a reflective layer, a protective layer and the like, an injection molding machine (trade name “MO40D” manufactured by Nissei Plastic Industrial Co., Ltd.)
3H "), using a mold for DVD and a stamper (capacity: 2.6 GB) having a land-groove structure,
A 0.6 mm thick disk substrate was molded into a DVD disk by injection compression molding while controlling the cylinder temperature and the injection mold temperature.

Example 1 The inside of a stainless steel autoclave having a capacity of 5 L was sufficiently dried, and after purging with nitrogen, 3350 g of cyclohexane and 539 g of styrene were charged. Subsequently, 10.5 mmol of s-butyllithium was added to initiate polymerization. After stirring at a temperature of 40 ° C. for 2.0 hours to completely react styrene, 60 g of isoprene was added and reacted at 50 ° C. for 2.0 hours. Further, an amount corresponding to 2.3 mmol of tetramethoxysilane was added and reacted at 50 ° C. for 2.0 hours. Thereafter, 5 ml of ethanol was added to obtain a radial type styrene-isoprene block copolymer. Ni / silica-alumina catalyst (Ni loading 65% by weight)
Was added, and 530 g of methyl-t-butyl ether was added. The hydrogen pressure was 100 kgf / cm ² (9.8 MPa), and the temperature was 180 °.
A hydrogenation reaction was performed at 6 ° C. for 6 hours. The stirring speed was 800 rpm. After the temperature was returned to room temperature and the atmosphere was sufficiently replaced with nitrogen, the solution was taken out of the autoclave, and a membrane filter having a pore size of 0.1 μm (Fluoropore manufactured by Sumitomo Electric Industries, Ltd.)
When filtration under pressure was performed using, a colorless and transparent solution was obtained. GPC measurement showed that the mixture contained about 40% of a component having a number average molecular weight of 40,000 corresponding to one branched chain. Irga is added as a stabilizer to this solution.
Nox1010 (manufactured by Ciba Geigy) was added to the polymer in an amount of 0.5% by weight, and then concentrated and flushed under reduced pressure to distill off the solvent to obtain a massive colorless and transparent hydrogenated styrene-isoprene copolymer. 0.5 g of such a polymer
/ DL reduced viscosity η measured at 30 ° C in toluene solution
_sp / c was 0.41 dL / g. ^{When the} degree of hydrogenation was determined by ¹ H-NMR spectrum measurement, it was 98%.
The ¹ H-NMR spectrum shows 6.3 ppm to 6.8.
A signal having a peak peak at ppm could not be recognized. HDT was 108 ° C. Table 1 shows the properties of this polymer. Further, using this resin, the cylinder temperature is set to 335 ° C.
The temperature was set to 111 ° C. and the movable side was set to 111 ° C. to mold a DVD-RAM disk.

Example 2 The amount of the monomer used for polymerization was adjusted to 547 g of styrene and 63 g of isoprene, and 10.5 mmol of sec-butyl lithium added as a polymerization initiator was added.
Polymerization, coupling and hydrogenation were carried out in the same manner as in Example 3 except that 2.5 g of bis (trimethoxysilyl) ethane was added as a coupling agent to obtain a hydrogenated styrene-isoprene copolymer. Was. The reduced viscosity η _sp / c measured at 30 ° C. in a toluene solution having a concentration of 0.5 g / dL of the obtained hydrogenated styrene-isoprene copolymer was 0.68 dL / g. ^{When the} degree of hydrogenation was determined by ¹ H-NMR spectrum measurement, it was 99%. The ¹ H
No signal having an apex peak at 6.3 ppm to 6.8 ppm was observed in the NMR spectrum. GPC measurement showed that the four-branched component was 55% by weight or more, and was a mixture containing about 26% of a component having a number average molecular weight of 46,000 corresponding to one branched chain.
The glass transition temperature measured by DSC was 145 ° C. HDT was 105 ° C. Table 1 shows the properties of this polymer. Using this resin, cylinder temperature 3
The DVD-RAM disk was molded at 35 ° C., the injection mold temperature was 109 ° C. on the fixed side, and 111 ° C. on the movable side.

[0047]

[Table 1]

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kaoru Iwata 2-1 Hinodecho, Iwakuni-shi, Yamaguchi Prefecture Teijin Co., Ltd. Inside the Iwakuni Research Center (72) Inventor Shunichi Matsumura 2-1 Hinodecho, Iwakuni-shi, Yamaguchi Prefecture Teijin Shares F-term in the Iwakuni Research Center (reference) 4F071 AA12 AA22 AA78 AA88 AF30 AF31 AF45 AF45Y AG07 AH19 BB05 BC01 4J100 AB00P AB02P AB03P AS01Q AS02Q AS03Q AS04Q CA01 CA04 CA31 DA01 DA09 DA22 HA05 HB02 HB17 HC14 HC03 KA12

Claims (2)

[Claims] 1. An aromatic polyolefin having a radial structure, which is obtained by hydrogenation in the presence of a hydrogenation catalyst, and having the following (1) to (4) (1) an aromatic ring hydrogenation rate of 90 to 99.5% (2) ¹ H-NMR measured in deuterated chloroform at room temperature
In the spectrum, substantially no signal having a peak peak in a region of 6.3 to 6.8 ppm is exhibited. (3) Reduced viscosity (in toluene, 0.5 g / dl, 30 ° C.)
) Is 0.2 or more. (4) An optical disk substrate made of an alicyclic polyolefin satisfying a heat distortion temperature (HDT) of 80 ° C. or more. 2. The optical disk substrate according to claim 1, wherein the aromatic polyolefin is a copolymer of styrene and a conjugated diene.