JP2000169521A - Hydrogenated polymer, resin composition, and molding material for information recording medium substrate - Google Patents

Abstract

(57) [Summary] A molding material capable of obtaining an information recording medium substrate having both a sufficiently small birefringence value and excellent mechanical strength, and a substrate excellent in moisture resistance can be obtained. Provided are a hydrogenated polymer and a resin composition as a molding material having excellent moldability and the like, and an information recording medium substrate formed by molding the hydrogenated polymer and a composition of the hydrogenated polymer. Kind Code: A1 A hydrogenation rate of an aromatic ring obtained by hydrogenating an aromatic vinyl polymer is 97% or more, and a ratio (Mw / M) between a weight average molecular weight (Mw) and a number average molecular weight (Mn) is obtained.
n) is 2.0 or less, the weight average molecular weight (Mw) is 100,
000-300,000 and a molecular weight (M) of 10,000
A resin composition containing a hydrogenated polymer having a component of 00 or less in an amount of 2% by weight or less based on the total weight of the polymer, and a clouding inhibitor is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a hydrogenated aromatic vinyl polymer, a resin composition containing the hydrogenated polymer, and a substrate for an information recording medium. The present invention relates to a substrate for an information recording medium which is small in size and excellent in mechanical strength, a resin composition excellent in moisture resistance and molding processability, and a hydrogenated aromatic vinyl polymer which is suitable for obtaining these.

[0002]

2. Description of the Related Art Conventionally, a hydrogenated polymer obtained by hydrogenating an aromatic ring of an aromatic vinyl polymer such as polystyrene has been known as a molding material for an information recording medium substrate having a small birefringence. For example, JP-A-63-43910 discloses that a vinylcyclohexane component is contained in a molecular chain at 30% by weight.
It has been proposed to use the polymer contained above as a molding material for an optical disc substrate. Specifically, the hydrogenation rate of the aromatic ring portion is 97%, and the weight average molecular weight (Mw) is 92,000.
0, a hydrogenated aromatic vinyl polymer having a molecular weight distribution (Mw / Mn) of 1.84, and a hydrogenation rate of an aromatic ring portion of 8
An example is disclosed in which an optical disk substrate is formed using a hydrogenated aromatic vinyl polymer having a 5% weight average molecular weight (Mw) of 150,000 and a molecular weight distribution (Mw / Mn) of 1.87. . However, although it has been confirmed that these optical disc substrates have a high light transmittance, a low water absorption, and a relatively low birefringence value, the mechanical strength of the substrate is not sufficient, and the birefringence value is also insufficient. Had problems such as not being at a satisfactory level or having insufficient reliability such as long-term heat resistance.

Japanese Patent Application Laid-Open No. 1-318015 discloses an optical disk substrate made of a polyvinylcyclohexane resin having a number average molecular weight of 50,000 or more and a softening point of 150 ° C. or more. Has a hydrogenation ratio of the aromatic ring portion of 99%, a weight average molecular weight of 160,
Although an example in which an optical disk substrate is formed using 2,000 polyvinyl cyclohexane is disclosed, this optical disk has not been able to reduce the birefringence value to a satisfactory level. In view of the above, there is a demand for a molding material having a sufficiently small birefringence value, excellent mechanical strength, and a substrate in which various characteristics required for the substrate are highly balanced.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a molding material capable of obtaining an information recording medium substrate having a sufficiently small birefringence value and excellent mechanical strength. Another object of the present invention is to obtain a substrate having a sufficiently small birefringence value, excellent mechanical strength, and excellent moisture resistance, and a hydrogenation weight as a molding material excellent in molding workability and the like. It is an object of the present invention to provide an information recording medium substrate obtained by molding a united and resin composition, and a hydrogenated polymer and a composition of the hydrogenated polymer.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, they have a specific range of molecular weight and a narrow molecular weight distribution, and the aromatic ring portion is highly hydrogenated. It has been found that a substrate for an information recording medium molded using the specified hydrogenated polymer has not only sufficiently small birefringence but also excellent mechanical strength, and further has a molecular weight (M) of 10,000. The following component content is a certain amount or less of the hydrogenated polymer, or a resin composition containing the hydrogenated polymer and a specific compounding agent, in addition to the above properties, anti-white turbidity in a high temperature and high humidity environment It has been found that it can be molded into a molded article having excellent moisture resistance and surface smoothness, and that the molded article is suitable as an optical component material, and is particularly suitable as a material for an information recording medium substrate. . The present inventors have completed the present invention based on these findings.

Thus, according to the present invention, (1) a compound obtained by hydrogenating an aromatic vinyl polymer,
Hydrogenation rate of aromatic ring is 97% or more, ratio of weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw / Mn)
Is 2.0 or less and the weight average molecular weight (Mw) is 100,00
0 to 300,000 and a molecular weight (M) of 10,000
There is provided a hydrogenated polymer wherein the following components are 2% by weight or less based on the total weight of the polymer. According to the present invention, there is provided a resin composition comprising the hydrogenated polymer according to (2) and (1) and an anti-clouding agent. According to the present invention, (3) the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) obtained by hydrogenating an aromatic vinyl polymer and having a hydrogenation rate of an aromatic ring of 97% or more. (Mw / Mn) is 2.0 or less,
Weight average molecular weight (Mw) of 100,000 to 300,0
A molding material for an information recording medium substrate, comprising a hydrogenated polymer of No. 00. According to the present invention, there is provided (4) a molding material comprising the hydrogenated polymer described in (1) or the resin composition described in (2). According to the present invention, (5) (3)
Or (4) An information recording medium substrate formed by molding the molding material according to any one of (4) and (4).

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Molding material for information recording medium substrate The molding material for an information recording medium substrate of the present invention has a hydrogenation rate of an aromatic ring obtained by hydrogenating an aromatic vinyl polymer. 97% or more, the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 2.0 or less, and the weight average molecular weight (Mw) is 100,000 to 30
(2) a hydrogenated polymer of the above (1) wherein the component having a molecular weight (M) of 10,000 or less is 2% by weight or less based on the total weight of the polymer, or (3) )
It consists of any of the resin compositions obtained by blending the anti-clouding agent with the hydrogenated polymer of (2).

Hydrogenated Polymer The hydrogenated polymer of the present invention is obtained by hydrogenating an aromatic ring of an aromatic vinyl polymer.

The hydrogenation rate of the aromatic ring of the hydrogenated polymer of the present invention is 97% or more, preferably 98% or more, more preferably 99% or more of the total aromatic rings of the aromatic vinyl polymer. If the hydrogenation rate of the aromatic ring is too small, the birefringence increases, which is not preferable. In addition, the hydrogenation rate of the aromatic ring can be determined by ¹ H-NMR measurement.

In the present invention, the weight average molecular weight (Mw) of the hydrogenated aromatic vinyl polymer is 100,000 to 100,000 in terms of polystyrene measured by GPC.
300,000, preferably 100,000-270,
000, more preferably 100,000 to 250,000.
0, and the molecular weight distribution is determined by weight average molecular weight (Mw) and number average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography (GPC).
It is important that the ratio (Mw / Mn) to n) be 2.0 or less, preferably 1.7 or less, more preferably 1.3 or less. Mw / M of hydrogenated aromatic vinyl polymer
If n is excessively large, there will be problems in that the mechanical strength is inferior and a sufficient molded product cannot be obtained, and that the birefringence increases. On the other hand, if the weight average molecular weight (Mw) is excessively small, the resulting molded article is inferior in mechanical strength and a sufficient molded article cannot be obtained.

Further, a hydrogenated product suitable in the present invention is such that the content of components having a molecular weight (M) of 10,000 or less in the hydrogenated polymer is 2% by weight or less, preferably 1.5% by weight based on the total weight of the polymer. %, More preferably 1% by weight or less. By adjusting the content of the component having a molecular weight (M) of 10,000 or less to the above range, the smoothness of the surface of a molded product molded by using the polymer hydrogenated product is improved, and the optical component, in particular, information recording is improved. Excellent performance as a medium substrate.

The aromatic vinyl compound used as a raw material is
The ratio (Mw / Mn) between the weight average molecular weight (Mw) and the number average molecular weight (Mn) is usually 2.0 or less, and the weight average molecular weight (Mw) is 100,000 to 400,000, preferably 100,000 to 300,000, more preferably 1
00,000 to 280,000. If the weight average molecular weight (Mw) of the aromatic vinyl polymer as the raw material is excessively large, the hydrogenation reaction of the aromatic ring becomes difficult,
When the hydrogenation reaction is forcibly advanced to about%, the molecular chain distribution reaction, which is a competitive reaction, proceeds and the molecular weight distribution increases, and the strength characteristics and heat resistance decrease due to the increase of low molecular weight components. If it is excessively small, it is inferior in strength properties and a sufficient molded product cannot be molded, and both are not preferred.

[0013] The aromatic vinyl polymer used as a raw material is not particularly limited in the production method, but a preferred method is, for example, an aromatic vinyl compound or an aromatic vinyl compound and a copolymerizable with the aromatic vinyl compound. Monomer and
It is obtained by (co) polymerization in a hydrocarbon solvent.

(Aromatic Vinyl Compound) The aromatic vinyl compound is not particularly limited as long as it is a compound having an aromatic ring and a polymerizable vinyl group. As a representative example of the aromatic vinyl compound,

[0015]

Embedded image

(In the chemical formula 1, R1 represents a hydrogen atom or an alkyl group, and R2 to R6 each independently represent a hydrogen atom, an alkyl group or a halogen atom.)

## STR1 ## R in Chemical Formula 1
The 1 alkyl group is preferably a lower alkyl group having 1 to 5 carbon atoms, and specifically, a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, Examples include a tert-butyl group and an amyl group. R2 to R6 are preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or a lower alkyl group similar to R1. R2
Examples of the halogen atom for R6 include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Specific examples of the aromatic vinyl compound include, for example, styrene, α-methylstyrene, α-ethylstyrene, α-propylstyrene, α-isopropylstyrene, α-t-butylstyrene, 2-methylstyrene,
-Methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-
Examples thereof include t-butylstyrene, 5-t-butyl-2-methylstyrene, monochlorostyrene, dichlorostyrene, and monofluorostyrene.

Among these, styrene, α-methylstyrene, α-ethylstyrene, α-propylstyrene,
α-isopropylstyrene, α-t-butylstyrene,
2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-diisopropylstyrene, 2,4-
Dimethylstyrene, 4-t-butylstyrene, 5-t-
Butyl-2-methylstyrene and the like are preferable, and styrene, α-methylstyrene, α-ethylstyrene, α-propylstyrene, α-isopropylstyrene, α-t-
Butylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-t-butylstyrene are particularly preferred.

These aromatic vinyl compounds can be used alone or in combination of two or more.

(Copolymerizable Monomer) Examples of the monomer copolymerizable with the aromatic vinyl compound include those which can be copolymerized with the aromatic vinyl compound in a polymerization method such as radical polymerization, anionic polymerization, or cationic polymerization. Is not particularly limited as long as it is 1,3-butadiene, isoprene, 2,3-
Conjugated diene monomers such as dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene;
Nitrile monomers such as acrylonitrile, methacrylonitrile and α-chloroacrylonitrile; (meth) acrylate monomers such as methyl methacrylate and methyl acrylate; acrylic acid, methacrylic acid, maleic anhydride, etc. Unsaturated fatty acid-based monomers;
Polyolefins such as ethylene and propylene; and phenylmaleimide. Monomers copolymerizable with these aromatic vinyl compounds are each independently,
Alternatively, two or more kinds can be used in combination.

The amount of the aromatic vinyl compound used to obtain the aromatic vinyl polymer is appropriately selected according to the purpose of use, but is usually 50% by weight or more based on all monomers.
Preferably 70% by weight or more, more preferably 90% by weight
As described above, the content is most preferably 100% by weight. As the proportion of the aromatic vinyl compound in the aromatic vinyl polymer increases, the birefringence of the hydrogenated product becomes sufficiently small.

Examples of the initiator used in this polymerization include those composed of an organic alkali metal and those composed of a combination of an organic alkali metal and a Lewis base. In order to narrow the molecular weight distribution, an organic alkali metal is used. Those comprising a combination of and a Lewis base are preferred. As the organic alkali metal, for example, n-butyl lithium, se
Monoorganic lithium compounds such as c-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; dilithiomethane, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5- Polyfunctional organic lithium compounds such as trilithiobenzene; sodium naphthalene, potassium naphthalene and the like; Among these, organolithium compounds are preferred, and monoorganic lithium compounds are particularly preferred.

These organic alkali metals can be used alone or in combination of two or more. The amount of the organic alkali metal used is appropriately selected depending on the required molecular weight of the produced polymer.
0.05 to 100 mmol, preferably 0.10 to 50 mmol, more preferably 0.15 to 2 per 100 parts by weight.
The range is 0 mmol.

The Lewis base is useful for obtaining an aromatic vinyl polymer having a narrow molecular weight distribution. The Lewis base is not particularly limited as long as it is commonly used in solution polymerization, and examples thereof include an ether compound; a tertiary amine compound such as tetramethylethylenediamine, trimethylamine, triethylamine, and pyridine; potassium-t-amyloxide; Alkali metal alkoxide compounds such as potassium-t-butyl oxide; phosphine compounds such as triphenylphosphine; and the like. Among them, ether compounds are particularly preferable because the molecular weight distribution (Mw / Mn) of the obtained aromatic vinyl polymer can be sufficiently narrowed.

The ether compound is not particularly limited, but usually has 2 to 100 carbon atoms, preferably 4 to 50 carbon atoms.
More preferably, those having 4 to 20 are suitably used. Specific examples include, for example, dimethyl ether, diethyl ether, diisopropyl ether, dibutyl ether,
Aliphatic monoethers such as diamyl ether, diisoamyl ether, methyl ethyl ether, methyl propyl ether, methyl isopropyl ether, methyl butyl ether, methyl isoamyl ether, ethyl propyl ether, ethyl isopropyl ether, ethyl butyl ether; anisole, phenetole, diphenyl ether , Dibenzyl ethers and other aromatic monoethers; tetrahydrofurans, tetrahydropyrans and other cyclic monoethers;

Ethylene glycol dimethyl ether, ethylene glycol methyl ethyl ether, ethylene glycol diethyl ether, ethylene glycol dipropyl ether, ethylene glycol dibutyl ether, ethylene glycol diamyl ether, ethylene glycol dioctyl ether, propylene glycol dimethyl ether, propylene glycol dimethyl ether, propylene glycol Alkylene glycol dialkyl ethers such as diethyl ether, propylene glycol dibutyl ether, isopropylene glycol dimethyl ether, isopropylene glycol diethyl ether, butylene glycol dimethyl ether, butylene glycol diethyl ether, butylene glycol dibutyl glycol; Alkylene glycol alkyl aryl ethers such as glycol methyl ether, alkylene glycol diaryl ethers such as ethylene glycol diphenyl ether, alkylene glycol di aralkyl ethers such as ethylene glycol dibenzyl ether; and the like.

Each of these Lewis bases, alone,
Alternatively, two or more kinds can be used in combination.
These Lewis bases are used in an amount of 0.001 to 10.0 mmol, preferably 0.01 to 5.0 mmol, more preferably 0.1 to 2.0 mmol, per 1 mol of the organic alkali metal used as the initiator. The range is 0 mmol.

The hydrocarbon solvent used in the polymerization is not particularly limited as long as it can dissolve the polymer and does not deactivate the initiator. For example, n-butane, n-pentane, iso-pentane, n-hexane,
aliphatic hydrocarbons such as n-heptane and iso-octane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane and decalin; aromatic hydrocarbons such as benzene and toluene; No. Among these, the use of aliphatic hydrocarbons and alicyclic hydrocarbons is preferable because the hydrogenation reaction can be carried out as it is. These hydrocarbon solvents are used singly or in combination of two or more kinds, and are usually used in a ratio such that the monomer concentration becomes 1 to 30% by weight.

The polymerization reaction may be either an isothermal reaction or an adiabatic reaction, usually at 0 to 150 ° C., preferably at 20 to 12 ° C.
It is carried out in a polymerization temperature range of 0 ° C. The polymerization time is 0.01
-20 hours, preferably 0.1-10 hours.

After the polymerization reaction, the polymer can be recovered by a known method such as a steam stripping method, a direct desolvation method, or an alcohol coagulation method. In the present invention, when a solvent inert to the hydrogenation reaction is used during the polymerization, the polymer can be directly used for the hydrogenation step without recovering the polymer from the polymerization solution.

The hydrogenation method of the aromatic vinyl polymer is not particularly limited as long as the hydrogenation rate of the aromatic ring is high and the polymer chain is hardly broken. For example, in an organic solvent, nickel, cobalt, iron, titanium,
A method using a hydrogenation catalyst containing at least one metal selected from rhodium, palladium, platinum, ruthenium and rhenium can be mentioned. Among the hydrogenation catalysts, a nickel catalyst is particularly preferable because a hydrogenated product having a small Mw / Mn can be obtained. The hydrogenation catalyst may be either a heterogeneous catalyst or a homogeneous catalyst.

The heterogeneous catalyst can be used as it is as a metal or a metal compound, or supported on a suitable carrier. Examples of the carrier include activated carbon, silica, alumina, calcium carbonate, titania, magnesia, zirconia, diatomaceous earth (diatomaceous earth), and silicon carbide.
Among them, the use of diatomaceous earth is preferable because the molecular weight distribution can be narrowed. In this case, the amount of the metal supported on the carrier is usually 0.01 to 80% by weight.
, Preferably in the range of 0.05 to 60% by weight.

As a homogeneous catalyst, nickel, cobalt,
A catalyst obtained by combining a compound of titanium or iron with an organic metal compound such as an organic aluminum compound or an organic lithium compound; an organic metal complex such as rhodium, palladium, platinum, ruthenium, or rhenium can be used. Examples of the nickel, cobalt, titanium or iron compound used for the homogeneous catalyst include acetylacetone salts, naphthenates, cyclopentadienyl compounds and cyclopentadienyl dichloro compounds of various metals. Examples of the organic aluminum compound include alkyl aluminum such as triethyl aluminum and triisobutyl aluminum; alkyl aluminum halide such as diethyl aluminum chloride and ethyl aluminum dichloride;
Alkyl aluminum hydride such as diisobutyl aluminum hydride; and the like. Examples of the organometallic complex include a γ-dichloro-π-pentene complex, a dichloro-tris (triphenylphosphine) complex, and a hydride-chloro-tris (triphenylphosphine) complex of each of the above metals.

Each of these hydrogenation catalysts can be used alone.
Alternatively, two or more kinds can be used in combination.
The amount of the hydrogenation catalyst to be used is generally 0.03 to 50 parts by weight, preferably 0.1 to 100 parts by weight, per 100 parts by weight of the aromatic vinyl polymer.
It is in the range of 16 to 33 parts by weight, more preferably 0.33 to 15 parts by weight.

Examples of the organic solvent used in the hydrogenation method include the above-mentioned aliphatic hydrocarbons; the above-mentioned alicyclic hydrocarbons; ethers such as tetrahydrofuran and dioxane; alcohols;
These organic solvents can be used alone or in combination of two or more. The amount of the organic solvent used is such that the concentration of the aromatic vinyl polymer is usually 1 to 50% by weight, preferably 3 to 40% by weight, more preferably 5 to 5% by weight.
It is used in the range of 30% by weight.

The hydrogenation reaction is usually carried out at a temperature of 10 to 25.
0 ° C, preferably 50-200 ° C, more preferably 80 ° C.
To 180 ° C. and the hydrogen pressure is usually 1 to 300
kg / cm ² , preferably 10 to 250 kg / cm ² ,
More preferably, it is performed in the range of 20 to 200 kg / cm ² .

Resin Composition The resin composition of the present invention has a molecular weight distribution of 2.0 or less and a molecular weight (M) of 10,000 or less among the above specific hydrogenated aromatic vinyl polymer polymers. The composition comprises 2% by weight or less of the total weight of the polymer and an anti-clouding agent. By using the resin composition as a molding material, it is possible to obtain a molded product excellent in white turbidity prevention effect and molding processability. The clouding prevention effect refers to a property that does not cause clouding of a molded product in a high-temperature and high-humidity environment or in a steam resistance test. Refers to the property of obtaining a molded article having excellent surface smoothness with few surface defects.

The cloudiness-inhibiting agent used in the present invention, when blended in a fixed amount with a hydrogenated aromatic vinyl polymer, has the above-mentioned effect of preventing cloudiness, that is, in a high-temperature high-humidity environment or a steam resistance test. And a substance capable of imparting a function of preventing white turbidity of a molded article comprising the hydrogenated polymer. Examples of such an anti-opacity agent include polymers other than the hydrogenated polymer,
Examples include at least one substance selected from the group consisting of a partial ether compound of a polyhydric alcohol, a partial ester compound of a polyhydric alcohol, and a fine particle filler.

(Polymer other than the hydrogenated polymer) In the present invention, the polymer other than the hydrogenated polymer which can be blended with the above-mentioned hydrogenated aromatic vinyl polymer is the aromatic polymer of the present invention. When blended with hydrogenated vinyl polymer,
There is no particular limitation as long as it is a polymer that imparts the clouding prevention effect, but in order to impart the moisture resistance, when blending the polymer with a hydrogenated aromatic vinyl polymer,
It is such that the shape of the polymer prior to compounding changes such that it can form, for example, a microdomain state and be dispersed in the hydrogenated polymer.

Examples of such polymers include soft polymers such as rubbery polymers and thermoplastic elastomers, and resins. Specific examples of the resin include polyethers or polythioethers such as polyphenylene sulfide and polyphenylene ether; polyester polymers such as aromatic polyester, polyarylate, polyethylene terephthalate, polybutylene terephthalate, polycarbonate and polyether ketone; polyethylene, polypropylene Polyolefin-based polymers such as polystyrene, poly-4-methyl-pentene-1, general-purpose transparent resins such as polymethyl methacrylate, cyclohexyl methacrylate and methyl methacrylate copolymer, polyacrylonitrile styrene (AS resin); acrylic resins; MS resins Liquid crystal plastics and the like;

The soft polymer used in the present invention is a polymer having a glass transition temperature of usually 40 ° C. or lower, and includes a usual rubbery polymer and a thermoplastic elastomer. When the glass transition temperature of a block copolymerized rubbery polymer or the like has two or more points, it can be used as a soft polymer if the lowest glass transition temperature is 40 ° C. or lower.

Specific examples of the rubbery polymer include isoprene rubber and its hydrogenated product; chloroprene rubber and its hydrogenated product; ethylene / propylene copolymer, ethylene / α-olefin copolymer, propylene / α-olefin Saturated polyolefin rubber such as copolymer; ethylene
Diene copolymers such as propylene / diene copolymer, α-olefin / diene copolymer, diene copolymer, isobutylene / isoprene copolymer, isobutylene / diene copolymer, and halides thereof, and the diene Acrylonitrile-butadiene copolymer and hydrogenated product thereof; vinylidene fluoride / ethylene trifluoride copolymer, vinylidene fluoride / propylene hexafluoride copolymer Fluorinated rubber such as vinylidene fluoride / propylene hexafluoride / ethylene tetrafluoride copolymer, propylene / tetrafluoroethylene copolymer; urethane rubber, silicone rubber, polyether rubber, acrylic rubber, chlorosulfonated polyethylene Rubber, epichlorohydrin rubber, propylene oxide rubber Special rubbers such as ethylene acrylic rubber; copolymers of norbornene monomers and ethylene or α-olefins; terpolymers of norbornene monomers and ethylene and α-olefins; norbornene monomers Ring-opening polymers, norbornene-based rubbery polymers such as hydrogenated ring-opening polymers of norbornene-based monomers; styrene-butadiene obtained by emulsion polymerization or solution polymerization;
Examples include random copolymers such as rubber and high styrene rubber, and hydrogenated products thereof.

Specific examples of the thermoplastic elastomer include styrene / butadiene / styrene / rubber, styrene / isoprene / styrene / rubber, and styrene / ethylene / styrene.
Styrene thermoplastic elastomers such as linear or radial block copolymers of aromatic vinyl monomers such as butadiene, styrene and rubber, and conjugated dienes, and hydrogenated products thereof; urethane thermoplastic elastomers; polyamide thermoplastic elastomers 1,2-polybutadiene-based thermoplastic elastomer; vinyl chloride-based thermoplastic elastomer; fluorine-based thermoplastic elastomer;

Among these, a copolymer of an aromatic vinyl monomer and a conjugated diene monomer and a hydrogenated product thereof are preferable because of good dispersibility of the hydrogenated aromatic vinyl polymer. The copolymer of the aromatic vinyl monomer and the conjugated diene monomer may be a block copolymer or a random copolymer. From the viewpoint of weather resistance, those in which a portion other than the aromatic ring is hydrogenated are more preferable. In particular,
Styrene / butadiene block copolymer, styrene / butadiene / styrene / block copolymer, styrene / isoprene / block copolymer, styrene / isoprene /
Styrene / block copolymers and their hydrogenated products, styrene / butadiene / random copolymers and their hydrogenated products, and the like.

The addition of the above polymers often leads to
A large number of dispersed microdomains are formed in the molded article.
Average particle size of microdomains observed by electron microscope (microdomain 1 randomly selected by electron microscope observation)
The major axis and minor axis of each of the 00 pieces were measured, and the measured values were used to calculate the microdomain diameter according to the formula [(major axis + minor axis) / 2], and the average of the calculated values was obtained. ) Is usually 0.
001 to 0.5 μm, preferably 0.005 to 0.3 μm
m, particularly preferably 0.01 to 0.2 μm. When such microdomains are formed, the transparency of the molded article and the effect of preventing white turbidity in a high-temperature and high-humidity environment are highly balanced, which is preferable.

(Partial ether compound and partial ester compound) The partial ether compound used in the present invention is a compound having at least one alcoholic hydroxyl group and at least one ether bond. An organic compound having one alcoholic hydroxyl group and at least one ester bond. By blending the partial ether compound or the partial ester compound with the hydrogenated aromatic vinyl polymer, it is possible to prevent cloudiness in a high-temperature and high-humidity environment, and to maintain high transparency. A compound having at least one alcoholic hydroxyl group and at least one ether bond includes at least one alcoholic hydroxyl group that is not a phenolic hydroxyl group and at least one etheric bond unit in the molecule.
There is no particular limitation as long as it has an organic compound. The partial ether compound is obtained by etherifying at least one of the hydroxyl groups in the polyhydric alcohol. The polyhydric alcohol has two or more, preferably three or more, more preferably three to eight hydroxyl groups.

The compound having at least one alcoholic hydroxyl group and at least one ester bond includes at least one alcoholic hydroxyl group other than a phenolic hydroxyl group and at least one ester bond unit in the molecule. There is no particular limitation as long as it has an organic compound. The partial ester compound is obtained by esterifying at least one of the hydroxyl groups in the polyhydric alcohol. The polyhydric alcohol has two or more, preferably three or more, more preferably three to eight hydroxyl groups.

Examples of the polyhydric alcohol include polyethylene glycol, glycerol, trimethylolpropane, pentaerythritol, diglycerol, triglycerol, dipentaerythritol, 1,6,7-trihydroxy-2,2-di (hydroxymethyl) -4-oxoheptane, sorbitol, 2-methyl-1,6,7
-Trihydroxy-2-hydroxymethyl-4-oxoheptane, 1,5,6-trihydroxy-3-oxohexanepentaerythritol, tris (2-hydroxyethyl) isocyanurate and the like. Trihydric or higher polyhydric alcohol,
Polyhydric alcohols having eight hydroxyl groups are preferred. When obtaining a partial ester compound, glycerol from which a partial ester compound containing α, β-diol can be synthesized,
Diglycerol, triglycerol and the like are preferred.

Specific examples of such partial ether compounds and partial ester compounds include glycerin monostearate, glycerin monolaurate, glycerin monobehenate, diglycerin monostearate, glycerin distearate, glycerin dilaurate, and pentaerythritol monoester. Etherified products and esterified products of polyhydric alcohols such as stearate, pentaerythritol monolaurate, pentaerythritol monobeherate, pentaerythritol peristearate, pentaerythritol dilaurate, pentaerythritol tristearate, and dipentaerythritol distearate ;

3- (octyloxy) -1,2-propanediol, 3- (decyloxy) -1,2-propanediol, 3- (lauryloxy) -1,2-propanediol, 3- (4-nonyl) Phenyloxy) -1,2
-Propanediol, 1,6-dihydroxy-2,2
-Di (hydroxymethyl) -7- (4-nonylphenyloxy) -4-oxoheptane, an ether compound obtained by reacting a condensate of p-nonylphenyl ether and formaldehyde with glycidol, and a compound of p-octylphenyl ether and formaldehyde Examples include ether compounds obtained by reacting a condensate with glycidol, and ether compounds obtained by reacting a condensate of p-octylphenyl ether and dicyclopentadiene with glycidol.

These partial ether compounds or partial ester compounds of polyhydric alcohols are used alone or in combination of two or more. Although the molecular weight of the partial ether compound or partial ester compound of these polyhydric alcohols is not particularly limited, those having a molecular weight of usually from 500 to 2,000, preferably from 800 to 1,500 are preferable because they do not decrease the transparency.

(Fine Particle Filler) Examples of the fine particle filler used in the present invention include organic and inorganic fillers, but are not particularly limited as long as they are commonly used in the polymer industry. These fine particle fillers do not change shape when blended into the hydrogenated polymer,
It is one that can be dispersed in the hydrogenated polymer in the form of fine particles before blending. Therefore, polymers other than the hydrogenated polymer described above, even if the composition is the same, those that can be dispersed in the hydrogenated polymer while maintaining the fine particle shape before blending are the fine particle fillers. .

As the organic filler, ordinary organic polymer particles or crosslinked organic polymer particles can be used.
Specifically, for example, polyethylene, polypropylene,
Polyolefins such as polymethyl-1-butene, poly-4-methyl-1-pentene and poly1-butene; halogen-containing vinyls such as polyvinyl chloride, polyvinylidene chloride, polyvinyl fluoride, polyvinylidene fluoride, polychloroprene, and chlorinated rubber Polymers: α, β- such as polyarylate, polymethacrylate, polyacrylamide, polyacrylonitrile, acrylonitrile-butadiene-styrene copolymer, polyacrylonitrile, acrylonitrile-styrene-acrylate (co) polymer, etc.
(Co) polymers derived from unsaturated acids or their derivatives; polyvinyl alcohol, polyvinyl acetate, polyvinyl stearate, polyvinyl benzoate, polyvinyl maleate, polyvinyl bityral, polyallyl phthalate, polyallyl melamine, ethylene A polymer derived from an unsaturated alcohol and an amine or an acyl derivative or acetal thereof, such as a vinyl acetate copolymer;

A polymer derived from polyethylene oxide or bisglycidyl ether; polyphenylene oxide; polycarbonate; polysulfone; polyurethane; and urea resins; polyamides such as nylon 6, nylon 66, nylon 11, nylon 12, polyethylene terephthalate; Polyesters such as polybutylene terephthalate and poly 1,4-dimethylol / cyclohexane terephthalate; polyhydric compounds having a crosslinked structure derived from aldehydes such as phenol / formaldehyde resin, urea / formaldehyde resin, melamine / formaldehyde resin and phenol, urea or melamine Coalesce, for example, cellulose acetate, cellulose propionate, natural polymer compounds such as cellulose ethers; Mention may be made of the bridge particles.

Examples of the inorganic filler include Group 1 and Group 2 and 4
Tribe, 6th, 7th, 8th to 10th, 11th, 12th, 13th
Oxides, hydroxides, sulfides, nitrides, halides, carbonates, sulfates, acetates, phosphates, and salts of Group 14 and 14 elements
Phosphites, organic carboxylates, silicates, titanates, borates and their hydrated or complex compounds,
And natural mineral particles. Specifically, Group 1 element compounds such as lithium fluoride and borax (sodium borate hydrate); magnesium carbonate, magnesium phosphate, magnesium oxide, magnesium chloride, magnesium acetate, magnesium fluoride, magnesium titanate, magnesium silicate, and silicate Magnesium hydrate (talc), calcium carbonate, calcium phosphate, calcium phosphite, calcium sulfate (gypsum), calcium acetate, calcium terephthalate, calcium hydroxide, calcium silicate, calcium fluoride, calcium titanate, strontium titanate, carbonate Group 2 element compounds such as barium, barium phosphate, barium sulfate and barium phosphite;

Titanium dioxide (titania), titanium monoxide, titanium nitride, zirconium dioxide (zirconia),
Group 4 element compounds such as zirconium monoxide; Group 6 element compounds such as molybdenum dioxide, molybdenum trioxide, and molybdenum sulfide; Group 7 element compounds such as manganese chloride and manganese acetate; 8-10 such as cobalt chloride and cobalt acetate
Group 11 element compounds such as cuprous iodide; Group 12 element compounds such as zinc oxide and zinc acetate; aluminum oxide (alumina), aluminum fluoride, aluminosilicate (alumina silicate, kaolin, kaolinite), etc. Group 13 element compounds of silicon; silicon oxide (silica, silica gel), graphite, carbon, graphite, glass, etc.
Group 4 element compound; particles of natural minerals such as kernalite, kainite, mica (mica, kinmo) and virose ore.

The average particle diameter of the inorganic filler is 0.05 to 50 μm, preferably 0.1 to 30 μm, which is the average particle diameter measured from the diameter of 3000 to 5000 particles by an electron microscope or the like. . Spherical particles having a ratio of the length of the long side to the length of the short side (= major axis / minor axis) of 2 or less than the acicular particles are preferable. When the size of the filler is in this range, a high balance between transparency and the effect of preventing white turbidity in a high temperature and high humidity environment can be obtained.

Among these anti-opacity agents, soft polymers, partial ether compounds and partial ester compounds have a high balance of transparency, heat resistance, moldability, and anti-opacity effect under high temperature and high humidity environment. It can be preferred.

In the present invention, the above-mentioned anti-clouding agent is blended in an appropriate amount with the hydrogenated aromatic vinyl polymer. The amount is determined by the combination of the hydrogenated aromatic vinyl polymer and the anti-opacity agent. Generally, if the amount is too large,
The glass transition temperature and transparency of the resin composition are greatly reduced,
Unsuitable for use as an optical material. If the amount is too small, the molded product may become cloudy under high temperature and high humidity. The amount of the clouding inhibitor is usually 0.01 to 1 with respect to 100 parts by weight of the hydrogenated aromatic vinyl polymer.
0 parts by weight, preferably 0.02 to 5 parts by weight, particularly preferably 0.05 to 2 parts by weight. When the amount is within the above range, the heat resistance and transparency of the molded article and the effect of preventing white turbidity in a high-temperature and high-humidity environment are highly balanced, which is preferable.

An information recording medium substrate was formed by using a resin composition containing a partial ether compound or a partial ester compound among the above whitening preventing agents, and a recording film layer for information recording was formed on the substrate. In this case, in addition to the effect of preventing turbidity under high temperature and high humidity, it is effective because it can prevent the adhesion of the recording film layer under a high temperature and high humidity environment, a partial peeling phenomenon such as blister, corrosion of the recording film layer, and the like. .

(Antioxidant) The hydrogenated aromatic vinyl polymer of the present invention and the resin composition are used for the purpose of preventing deterioration, decomposition and the like due to oxidation during molding, and preventing oxidation and the like in a use environment. It is preferable to add an antioxidant. Examples of the antioxidant include a phenolic antioxidant, a phosphorus-based antioxidant, and a sulfur-based antioxidant. Among these, a phenol-based antioxidant is preferable, and an alkyl-substituted phenol-based antioxidant is particularly preferable. preferable.

As the phenolic antioxidant, those conventionally known can be used. For example, 2-t-butyl-6-
(3-t-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2,4-di-
t-Amyl-6- (1- (3,5-di-t-amyl-2)
-Hydroxyphenyl) ethyl) phenyl acrylate and the like.
Acrylate compounds described in 68643;
Octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2,2′-methylene-bis (4-methyl-6-t-butylphenol),
1,1,3-tris (2-methyl-4-hydroxy-5
-T-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4)
-Hydroxybenzyl) benzene, tetrakis (methylene-3- (3 ′, 5′-di-tert-butyl-4′-hydroxyphenylpropionate) methane [namely, pentaerythrimethyl-tetrakis (3- (3,5 -Di-t
-Butyl-4-hydroxyphenylpropionate)], triethylene glycol bis (3- (3-t
Alkyl-substituted phenolic compounds such as -butyl-4-hydroxy-5-methylphenyl) propionate);
6- (4-hydroxy-3,5-di-t-butylanilino) -2,4-bisoctylthio-1,3,5-triazine, 4-bisoctylthio-1,3,5-triazine, 2- Octylthio-4,6-bis- (3,5-di-
triazine group-containing phenolic compounds such as t-butyl-4-oxyanilino) -1,3,5-triazine;

The phosphorus-based antioxidant is not particularly limited as long as it is generally used in the general resin industry. For example, triphenylphosphite, diphenylisodecylphosphite, phenyldiisodecylphosphite, 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-
Monophosphite compounds such as 10-oxide;
4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-di-tridecyl phosphite), 4,
Diphosphite-based compounds such as 4′-isopropylidene-bis (phenyl-di-alkyl (C12-C15) phosphite); Among these, a monophosphite compound is 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-based antioxidants include dilauryl 3,3-thiodipropionate, dimyristyl 3,3′-thiodipropionate, distearyl 3,3-thiodipropionate, lauryl stearyl 3,3-thiodipropionate. Pionate, pentaerythritol-tetrakis- (β-lauryl-thio-propionate, 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro
[5,5] undecane and the like.

These antioxidants are each used alone,
Alternatively, two or more kinds can be used in combination.
The compounding amount of the antioxidant is appropriately selected within a range not to impair the object of the present invention. , Preferably in the range of 0.01 to 1 part by weight.

(Other Compounding Agents) The hydrogenated aromatic vinyl polymer and the resin composition of the present invention may contain, if necessary, an ultraviolet absorber, a light stabilizer, a near infrared absorber, a dye or a pigment. Other compounding agents such as coloring agents, lubricants, plasticizers, antistatic agents, fluorescent whitening agents and the like can be used alone or in combination of two or more, and the compounding amount does not impair the object of the present invention. It is appropriately selected within the range.

Information Recording Medium Substrate The information recording medium substrate of the present invention can be obtained by molding the above-mentioned information recording medium substrate molding material by a conventional molding method. Examples of the molding method that can be used include an injection molding method (injection compression molding method), a compression molding method, a press molding method, an extrusion molding method, a cast molding method, and the like. In order to obtain a substrate having excellent properties, it is preferable to use an injection molding method (including an injection compression molding method).

As a specific injection molding method, a method in which the molding material of the present invention is heated and melted using, for example, a heating cylinder or the like, and the molten molding material is filled in a mold and then cooled. Can be Inside the mold to be used,
A stamper is attached, and pits and grooves are transferred. The shape of the substrate is changed according to the standard of the substrate, the thickness is usually 0.05 to 10 mm, and the substrate diameter is usually 30.
mm to 300 mm. Molding conditions are not particularly limited, the cylinder set temperature of the molding machine 200 ~ 400 ℃,
Preferably 220-380 ° C, most preferably 240-
The mold temperature is preferably in the range of 360 ° C and the mold temperature is 50 to 180 ° C. If the temperature is too low, the transferability is lowered in any case, and the birefringence becomes large. If the temperature is too high, the molding cycle may be extended, burrs may occur, or the resin may be decomposed. Separate temperature of sprue,
For example, the temperature can be adjusted to 30 to 100 ° C.

At the time of the above molding, (A)
A method in which the inside of the cylinder and the mold is in a low oxygen concentration state and a method (B) of removing dissolved oxygen in the molding material before molding can be used, thereby further improving the surface smoothness of the molded product. I do. These molding methods have not only the hydrogenated aromatic vinyl polymer of the present invention and the composition, but also have an alicyclic structure such as conventionally known hydrogenated polystyrene, hydrogenated polyvinylcyclohexene, and polyvinylcyclohexane. Also applicable to polymers.

(A) (Method of Making Cylinder and Mold Inside Low Oxygen Concentration State during Molding) As a concrete method for making the cylinder and mold inside a low oxygen concentration state during molding, (1) molten resin The method of supplying the molding machine in a low oxygen concentration gas atmosphere,
(2) When the molten resin is supplied to the injection device for injection molding, a method in which the inside of the injection device is depressurized and the molten resin is melt-injected into a mold to produce a molded article can be exemplified. .

(1) Method of Supplying to Molding Machine in Low Oxygen Concentration Gas Atmosphere The method of supplying to the molding machine in a low oxygen concentration gas atmosphere is performed by using a hot-melt molding machine. In molding, the hydrogenated aromatic vinyl polymer resin is supplied to the molding machine in an atmosphere of a low oxygen concentration gas.
As a result, poor phenomena such as a decrease in molecular weight due to oxidation, decomposition, etc., coloring of molded products, generation of silver streaks, and peeling of the molded product surface due to adhesion of an aromatic vinyl polymer hydrogenated resin to a molding die. Is significantly improved. The low oxygen concentration gas is an inert gas with respect to the aromatic vinyl polymer hydrogenated resin, and usually contains 2% by volume or less, preferably 1% by volume or less of oxygen. Preferably 0.1% by volume or less, particularly preferably 0.0% by volume.
5% by volume or less, and specific examples include helium,
Neon, nitrogen, argon, xenon, krypton, carbon dioxide and the like.

Further, the inert gas used in the present invention desirably has a boiling point of -100 ° C. or less. That is, when an inert gas having a boiling point exceeding -100 ° C. is used, the inert gas is dissolved in the aromatic vinyl polymer hydrogenated resin, and the gas dissolved when producing a molded article is removed. By vaporization, the aromatic vinyl polymer hydrogenated resin may foam, and the molded article may have silver streaks or bubbles, so helium, neon, nitrogen, argon, and xenon are particularly preferable. preferable. The amount of the low oxygen concentration gas used is preferably a flow rate of 30 liters or more, more preferably 60 liters or more, particularly preferably 120 liters or more per 1 kg of the amount of the aromatic vinyl polymer hydrogenated resin supplied to the molding machine. To supply a low-oxygen-concentration gas to be in a low-oxygen-concentration gas atmosphere.

In the present invention, supplying the hydrogenated polymer in a low oxygen concentration gas atmosphere means that the aromatic vinyl polymer hydrogenated resin supplied to the heating cylinder of the molding machine is accompanied by air. In order to prevent heat melting, the air is replaced with a low oxygen concentration gas, and the amount of the air is reduced or eliminated as much as possible.

That is, the supply of the hydrogenated polymer to the molding machine in the present invention means the supply of the resin to a heating cylinder of a hot-melt molding machine. In order to replace the air accompanying the hydrogenated polymer with a low oxygen concentration gas, a method of creating a low oxygen concentration gas atmosphere includes, for example, an aromatic vinyl polymer hydrogenated resin attached to a molding machine. A low oxygen concentration gas is fed into the supply hopper, and the inside of the cylinder is set to a low oxygen concentration gas atmosphere. A method of inserting a low oxygen concentration gas into the cylinder from an arbitrary position to make the inside of the cylinder or the inside of the cylinder and the above hopper a low oxygen concentration gas atmosphere. A method of supplying the additive resin to the cylinder is exemplified. The hot-melt molding machine used in the method of molding in a low oxygen state is not particularly limited, and examples thereof include an injection molding machine and an extrusion molding machine.

(2) When supplying the molten resin to the injection device for injection molding, the inside of the injection device is depressurized to melt and inject the molten resin into a mold to produce a molded article. When supplying the vinyl polymer hydrogenated resin to the injection device for injection molding, the interior of the injection device is depressurized to melt and inject the aromatic vinyl polymer hydrogenated resin into the mold. Details of the method for producing the molded article are described below.

In the case of this method, first, the inside of the injection molding machine (cylinder) is depressurized by discharging gas from a vent hole provided in a rear portion of the cylinder of the injection device or a resin supply hopper portion. . The pressure inside the cylinder is usually 15 torr or less, preferably 8 to
The pressure is reduced to not more than rr, more preferably not more than 1 torr, particularly preferably not more than 0.5 torr. By melting and injecting the aromatic vinyl polymer hydrogenated resin resin under reduced pressure in this manner, for example, a gas component is generated from the aromatic vinyl polymer hydrogenated resin pellets, and drying of the pellets is not possible. Even if it is sufficient, the degradation of the molecular weight due to decomposition, the coloring of the molded product, the occurrence of silver streaks, the peeling of the surface of the molded product due to the adhesion of the aromatic vinyl polymer hydrogenated resin to the molding die, etc. In addition, the occurrence of defects in the appearance of the molded article can be suppressed.

Further, the air inside the injection device is discharged,
It is preferable to reduce the pressure after purging the inside of the hopper and the cylinder with the low oxygen concentration gas. By purging with a low oxygen concentration gas in this manner, optical properties such as transparency of the obtained molded body are further improved. The conditions for injection molding performed under reduced pressure as described above are the same when molding a polymer other than the hydrogenated polymer of the present invention.

(B) (Method for Removing Dissolved Oxygen in Molding Material Before Molding) As a pretreatment for the molding, the molding material is subjected to a heat treatment, a pressure reduction treatment, or a replacement under an inert gas atmosphere before the molding. By reducing the dissolved oxygen concentration in the molding material by using a method such as a treatment, and a combination treatment thereof, it is possible to prevent oxidation, decomposition, and the like of the molten molding material. The same effect as the processing can be obtained.

As a specific example of the method of lowering the dissolved oxygen concentration in the molding material, for example, the glass transition temperature (Tg−60) ° C. of the aromatic vinyl polymer hydrogenated resin and (Tg−5) ) 0.1 to 1 in the temperature range below ℃
For example, a method of subjecting an aromatic vinyl-based polymer hydrogenated resin to heat treatment for 00 hours, followed by melt molding. Heat treatment refers to placing the resin in an atmosphere in the above temperature range, and is not necessarily intended to remove moisture in the resin.

Although the amount of dissolved oxygen is reduced by maintaining the temperature within the above range, it is preferable to conduct the treatment in a low oxygen concentration atmosphere at the same time. The low oxygen concentration atmosphere means a low oxygen concentration gas atmosphere having an oxygen concentration of usually 5% by volume or less, preferably 3% by volume or less, more preferably 1% by volume or less, or usually 15 torr or less, preferably 8 torr or less, and Preferably, the pressure is reduced to 1 torr or less, or any method may be used.

The low oxygen concentration gas is a gas that is inert to the aromatic vinyl polymer hydrogenated resin,
For example, helium, neon, nitrogen, argon, xenon,
Examples thereof include krypton and carbon dioxide, and examples thereof include a diluted air atmosphere diluted with the inert gas so that the oxygen concentration is in the above range. The dryer used for the heat treatment is not particularly limited, and a hot air circulation-type shelf dryer, a hopper dryer, a shelf-type vacuum dryer, or a stirring-type vacuum dryer used for drying ordinary resin pellets can be used. .

It is desirable that the resin pellets after the heat treatment be promptly subjected to melt molding without any time. After heating and drying, the time until molding is usually within 12 hours,
Preferably within 6 hours, more preferably within 3 hours,
Particularly preferably, it is within one hour. In addition, it is preferable that the resin pellet is kept under a low oxygen concentration atmosphere during that time.

In addition to the heat treatment, it is more effective to store the resin pellets in a low oxygen concentration atmosphere before performing the heat treatment. That is, the oxygen concentration is usually 5% by volume or less, preferably 3% by volume or less, more preferably 1% by volume or less.
In a low oxygen concentration gas atmosphere of volume% or less, or
The storage is performed under a reduced pressure of 5 torr or less, preferably 8 torr or less, more preferably 1 torr or less, or a combination of these methods, and for example, dilute air diluted with a low oxygen concentration gas is stored under reduced pressure. The storage time under such a low oxygen concentration atmosphere is 1 hour or more, and more preferably 2 hours or more. It should be noted that the time for the low oxygen concentration atmosphere may be long without any problem.For example, after pellet production, when packing the resin, use a bag or a container with a small amount of oxygen permeation for the packaging, and then use the low oxygen concentration atmosphere The present invention includes filling, storing the package in a low oxygen concentration atmosphere for a long period of time, and drying it as it is.

As described above, the methods (A) and (B) are not limited to the molding of the specific hydrogenated aromatic vinyl polymer in the present invention, but may be any of the conventionally known aromatic vinyl polymer. When used for molding hydrogenated products or polymers having an alicyclic structure, reduction of molecular weight due to oxidation and decomposition of molding materials, coloring of molded products, generation of silver streaks, and aromatic vinyl-based molding molds This is effective because it is possible to prevent defective phenomena such as peeling of the molded product surface due to adhesion of the polymer hydrogenated resin. The effect is particularly remarkable when the information recording medium substrate is formed.

That is, a molding material containing (A) a hydrogenated polymer obtained by hydrogenating an aromatic vinyl polymer or a polymer of an unsaturated compound or a polymer of a saturated alicyclic vinyl compound, By using a molding method of molding under a low oxygen concentration atmosphere, a molding method of subjecting the molding material described in (B) or (A) to a heat treatment and / or a reduced pressure treatment, and then molding, the aromatic vinyl polymer Alternatively, it is formed by molding a material containing a hydrogenated polymer obtained by hydrogenating an unsaturated compound polymer or a polymer of a saturated alicyclic vinyl compound, and has a small birefringence, a high transmittance, and a
A molded article having a small number of surface defects by FM observation, preferably an information recording medium substrate is provided.

(Recording Film Layer) In the present invention, an information recording medium can be used by providing a recording film layer on an information recording medium substrate. The recording film layer is provided on the surface of the substrate obtained by the above method, an aluminum reflective film layer, or a film provided so that the reflectance of light can be locally changed irreversibly or reversibly. Is hundreds to thousands of angstros
The thickness is not more than 10,000 angstroms at most.

In a music CD, a CD-ROM, or the like, the information itself is cut on a stamper portion of a mold at the time of injection molding, and a fine groove corresponding to the information is formed on the substrate. If a reflective film layer such as aluminum or gold is formed on the surface by sputtering or the like, the groove and the reflective film layer form a recording film layer.

In a write-once type CD-R or a rewritable magneto-optical disk (MO), a recording film layer that reversibly or irreversibly changes light reflectance or transmittance, and a reflection film that reflects light. A film layer and a thin inorganic or organic protective film layer for protecting them and correcting optical distortion are formed. The information recording layer is formed by forming a single layer or a combination of these layers into a multilayer structure by a sputtering method, a gas layer growth method, a method using a chemical coating, or the like. For example, in a magneto-optical disk application, a magneto-optical recording medium (for example, Tb-Fe-Co, Pt-Tb-F) is used.
recording media such as e-Co); aluminum, gold or alloys thereof as a reflective layer; SiN, S as a thin protective film layer
An information recording layer in which iC or the like is laminated is used. In the case of a phase change type disc, Te-Ge-Sb, In-Sb-T
An information recording layer in which a reflective film layer similar to the above or a thin protective film layer is laminated on e, Te-Ge-Cr, Te-Ge-Zn, or an alloy thereof is used.

The thickness and formation method of these information recording layers differ depending on the type of each information recording medium substrate, and are formed according to a standard by a known method.

(Coat Layer) When the information recording medium substrate of the present invention is used as an information recording medium such as an optical disk, a coat layer for protecting the information recording layer from moisture and the like is usually used. I do.

(Coating Agent) The coating agent used for forming the coating layer may be a silicone coating agent or an organic coating agent. Silicone-based coating agents are partial hydrolysates of silane compounds. There is an ultraviolet curable coating agent that cures an ultraviolet-curable monomer or the like. An ultraviolet-curable coating agent is preferred because it can be cured under conditions in which the aromatic vinyl polymer hydrogenated resin is unlikely to be thermally deformed, and has sufficient hardness and weather resistance.

(Ultraviolet curable coating agent) The ultraviolet curable coating agent of the present invention contains a reactive monomer and / or a reactive oligomer, a photopolymerization initiator, and other additives.
Solvent-free or diluted with a solvent.

In the present invention, of the photopolymerizable monomers, those having an acrylate group are referred to as monofunctional acrylate monomers, difunctional acrylate monomers, and trifunctional acrylate monomers, depending on the number of acrylate groups. In the present invention, the acrylate group includes a methacrylate group, an ethacrylate group and the like in addition to the acrylate group in a narrow sense.

Examples of the monofunctional acrylate monomer include n-butyl acrylate, isoamyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 2-ethylhexyl methacrylate, phenoxyethyl acrylate, and phenoxypropyl acrylate. Above all,
In order to prevent the curing reaction from being inhibited by radical oxygen, those having only acrylate groups in a narrow sense without having a methacrylate group or the like are preferable. Those having a certain number of side chains are preferred.

In order to improve the adhesion to the hydrogenated aromatic vinyl polymer resin, it is also preferable to use a long-chain aliphatic monofunctional acrylate monomer or an alicyclic monofunctional acrylate monomer as described later. . The long-chain aliphatic monofunctional acrylate monomer preferably has 5 to 18 carbon atoms in the aliphatic portion, and more preferably 8 to 16 carbon atoms. If the carbon number is too small, the adhesiveness is poor, and if the carbon number is too large, crosslinking is difficult and the strength is poor. Specific examples of the long-chain aliphatic monofunctional acrylate monomer include lauryl acrylate, stearyl acrylate, octyl acrylate, isooctyl acrylate, decyl acrylate, and isodecyl acrylate. Specific examples of the alicyclic monofunctional acrylate monomer include tricyclo [5.2.1.0 ^2,6 ] decanyl acrylate, a hydrogenated product thereof, isobonyl acrylate,
Examples include cyclohexyl acrylate.

Examples of the bifunctional or trifunctional acrylate monomer include ethylene glycol, diethylene glycol, tripropylene glycol, butylene glycol, neopentyl glycol, hexanediol, tremethylolpropane, tetramethylolpropane, pentaerythritol, dipentaerythritol and the like. And a bisphenol F type epoxy acrylate which is obtained by esterifying two or three acrylic acids to the above polyols. Further, in order to improve the adhesiveness to the aromatic vinyl polymer hydrogenated resin, it is preferable to use an alicyclic bifunctional acrylate monomer as described later. Specific examples of the alicyclic bifunctional acrylate monomer include tricyclo [5.2.1.0 ^2,6 ] decanyl diacrylate, a hydrogenated product thereof, isobonyl diacrylate, and cyclohexyl diacrylate. You.

The acrylate monomer having four or more functional groups includes, for example, polyols such as tetramethylolpropane, pentaerythritol and dipentaerythritol.
Four or more, preferably four to eight acrylic acids are esterified. In particular, generally available 4- to 6-functional acrylate monomers are preferred.

Examples of the reactive oligomer include polyester acrylate having an acroyl group at the terminal, epoxy acrylate or polyurethane acrylate having an epoxy group in the molecular chain and an acroyl group at the terminal, unsaturated polyester having a double bond in the molecular chain, Examples thereof include 1,2-polybutadiene and other oligomers having an epoxy group or a vinyl ether group.

Examples of photopolymerization initiators include acetophenones such as 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone and chlorinated acetophenone; benzophenones: benzyl, methylorthobenzoylbenzoate, benzo Benzoins such as in alkyl ethers: azo compounds such as α, α′-azobisisobutyronitrile, 2,2′-azobispropane, hydrazone; organic peroxides such as benzoyl peroxide and ditertiary butyl peroxide Diphenyl disulfides such as diphenyl disulfide, dibenzyl disulfide and dibenzoyl disulfide; and the like.

The mixing ratio of the monofunctional acrylate monomer is usually 15 to 65% by weight, preferably 25 to 60% by weight, more preferably 30 to 60% by weight, based on the total weight of the acrylate monomer and the photopolymerization initiator. 55% by weight, 5 to 50% by weight of bifunctional or trifunctional acrylate monomer, preferably 6 to 40% by weight, more preferably 8 to 50% by weight.
30% by weight, 4-functional or higher acrylate monomer 10
60% by weight, preferably 12 to 50% by weight, more preferably 15 to 45% by weight, and the reactive oligomer is 0 to 60% by weight, preferably 10 to 50% by weight, more preferably 2% by weight.
0 to 40% by weight. If the amount of the reactive oligomer is too large, curing shrinkage becomes large and adhesion becomes poor. If the amount is too small, the viscosity may decrease, and it may be difficult to form a uniform film, or it may take time to cure.

The amount of the photopolymerization initiator is 1 to 10% by weight, preferably 2 to 6% by weight. If the amount of the acrylate monomer having four or more functional groups is too large, the curing shrinkage increases. If the amount is too small, the hardness of the cured layer decreases and the curing speed decreases. When the amount of the monofunctional acrylate monomer is small, the viscosity becomes high and the workability is poor. In addition, when the amount of the monofunctional acrylate monomer is large, the curing shrinkage decreases, and in addition, the amount of the bifunctional or trifunctional acrylate monomer decreases, which lowers the flexibility of the cured layer and causes cracks. In order to improve the adhesiveness, the amount of the bifunctional or trifunctional acrylate monomer is preferably large.

The ultraviolet-curable coating agent of the present invention comprises
It preferably contains at least 40% by weight of one or more monomers selected from long-chain aliphatic monofunctional acrylate monomers, alicyclic monofunctional acrylate monomers, and alicyclic bifunctional acrylate monomers, and contains at least 45% by weight. It is more preferable that the content be 50% by weight or more. The higher the content of one or more monomers selected from long-chain aliphatic monofunctional acrylate monomers, alicyclic monofunctional acrylate monomers, and alicyclic bifunctional acrylate monomers, the more the aromatic vinyl-based UV-curable coating agent is used. The adhesion to the polymer hydrogenated resin is improved.

As long as the adhesiveness and hardness of the cured layer are not impaired, a suitable additive may be added to the ultraviolet curable coating agent. For example, by adding a fluorine-based nonionic surfactant, the wettability with the base sheet and the surface smoothness after curing can be improved. In addition, by adding a suitable thermoplastic resin, the viscosity can be adjusted and the adhesiveness can be improved. Examples of the thermoplastic resin for improving the adhesiveness include an aromatic vinyl polymer hydrogenated resin or a resin having a structure similar thereto, such as a ring-opened polymer of a norbornene monomer, a dicyclopentadiene-based resin, and a diene-based resin. , Aliphatic and water white petroleum resins and hydrogenated products thereof.

(Antistatic Agent) The ultraviolet curable coating agent is
Particularly when used as a protective coating agent, it is preferable to add an antistatic agent in order to prevent the cured layer from being charged.
The antistatic agent is not particularly limited, and may be a general antistatic agent, but the nonionic antistatic agent is preferably an acrylate monomer. The nonionic antistatic agent has excellent compatibility with the acrylate monomer, and a uniform ultraviolet curable composition can be obtained.

When it is necessary to prevent the cured layer from being charged, the cured layer has a surface electric resistance of 5 × 10 ¹³ Ω or less, preferably 2 × 10 ¹³ Ω or less.
10 ¹³ Ω or less, more preferably 10 ¹³ Ω or less. For this purpose, the amount of the antistatic agent to be added is 1 to 7% by weight, preferably 1.5 to 5% by weight. Even if an antistatic agent is added to an ultraviolet curable coating agent in an amount sufficient to lower the surface electric resistance value, it has a practically acceptable adhesion to a molded article made of a hydrogenated aromatic vinyl polymer resin. A cured layer can be formed. If the adhesion becomes insufficient, it is preferable to form a primer layer using a primer composition as described below.

The above-mentioned coating agent can be used as it is, but depending on the necessity of operability or the like, an aromatic hydrocarbon solvent such as toluene, xylene and chloropentene; an alicyclic hydrocarbon such as cyclohexane and methylcyclohexane. System solvent: methyl isobutyl ketone, methyl ethyl ketone,
Ketone solvents such as acetone; ether solvents such as n-butyl ether, diethyl ether, etc .; ester solvents, cellosolve solvents, chloro solvents, etc .; It may be a curable coating agent.

(Formation of Primer and Primer Layer) In the present invention, a specific ultraviolet curable coating agent is applied to the surface of a molded article such as an optical disk, and the ultraviolet curable coating agent is cured by irradiating ultraviolet rays. A protective coat layer is formed, but a primer is applied before the application of the ultraviolet curable coating agent in order to further strengthen the adhesion between the aromatic vinyl polymer hydrogenated resin and the protective coat layer. Is also good. As the primer, a halogenated hydrocarbon polymer is preferable. Such a halogenated hydrocarbon polymer, ethylene, propylene, butadiene, isoprene, halogenated hydrocarbon polymer obtained by polymerizing or copolymerizing a hydrocarbon monomer such as styrene, or, Examples thereof include those obtained by polymerizing or copolymerizing a halogen-containing monomer such as vinyl chloride, vinylidene chloride, and chloroprene. Among them, those obtained by chlorinating a hydrocarbon polymer are preferable, and chlorinated polypropylene is particularly preferable.

The molecular weight of the halogenated hydrocarbon polymer is generally 5,000 to 200,000, preferably 10,000.
00 to 150,000, more preferably 20,000 to
100,000. If the molecular weight is too small, the strength of the primer layer will be low, and if it is too large, the viscosity will be too high and coating workability will be poor. The halogen content of the halogenated hydrocarbon polymer is usually 15 to 55% by weight, preferably 20 to 45% by weight, more preferably 25 to 35% by weight.
It is. Even if the content of halogen is too small or too large,
Adhesion between the protective coat layer and the surface of the molded article is deteriorated.

To the primer, a photopolymerizable monomer or a photopolymerizable oligomer described later may be added as a reactive diluent.
Addition at a ratio of 0% by weight is preferable because the adhesion between the protective coat layer and the primer layer and between the primer layer and the surface of the resin molded product is improved, and the protective coat layer is hardly peeled off from the molded product. . The primer is preferably dissolved in a solvent and used as a primer solution. The solvent is not particularly limited as long as it is a substantially poor solvent for the hydrogenated aromatic vinyl polymer resin. For example, toluene is a good solvent for an aromatic vinyl polymer hydrogenated resin, but when diluted to 70% by weight or less with methyl isobutyl ketone, it can be applied to an aromatic vinyl polymer hydrogenated resin molded article. However, since erosion is reduced, it can be used as a primer solvent.

Monofunctional acrylates such as n-butyl methacrylate and isoamyl methacrylate are also poor solvents for the aromatic vinyl polymer hydrogenated resin and, as described above, have an effect as a photopolymerizable monomer added to the primer. Is a reactive diluent having the formula: The solid concentration of the primer solution is usually 1 to 30% by weight, preferably 1.5 to 20% by weight,
More preferably, it is 2 to 10% by weight. The primer layer is formed by applying the primer solution to the surface of the aromatic vinyl-based polymer hydrogenated resin molded article and sufficiently removing the volatile components in the primer solution. However,
When only the reactive diluent as described above is used as the solvent for the primer, the operation of removing volatile components is not required.

The method for applying the primer solution to the coated surface is not particularly limited, and for example, spray, dipping, spin coating, roll coater and the like can be employed. The method for removing volatile components in the primer solution is not particularly limited. The volatilization temperature and time required to substantially remove the solvent of the primer solution vary depending on the type of solvent used, the amount of the primer solution applied, and the shape of the molded product on the application surface, but the aromatic vinyl polymer The conditions may be determined so that the hydrogenated resin molded article does not undergo thermal deformation and is not more than about 100 ° C. and is sufficiently removed. Specifically, 60
It is appropriate to leave at 100 ° C. for about 3 to 60 minutes. After removing volatile components at high temperature, 10
It is preferable to perform cooling for about 10 seconds to about 10 minutes, and to cool to near room temperature.

The amount of the primer solution applied is not particularly limited, but is preferably about 1 to 10 μm, particularly about 2 to 5 μm. When it is necessary to remove the volatile components after the application of the primer solution, it is preferable to adjust the thickness to the above-mentioned thickness after sufficiently removing the volatile components. If the amount of the primer solution is small, the effect of the primer solution is small.

(Formation of Coat Layer) In the present invention, if necessary, a primer layer is formed on the surface of an aromatic vinyl-based polymer hydrogenated resin molded article, and the ultraviolet curable coating agent is applied thereon. , Irradiate with ultraviolet light and cure,
Form a coat layer. The aromatic vinyl polymer hydrogenated resin molded article may be a molded article of the resin alone, or may be a composite with another material or molded article.
The coat layer is formed on the surface of the aromatic vinyl-based polymer hydrogenated resin substrate and the recording film layer, and is formed on the entire surface or on the surface portion particularly requiring abrasion resistance and scratch resistance.

The method of application is not particularly limited, and for example, spraying, dipping, spin coating, roll coater and the like are possible. When a solvent is used, it is sufficiently dried after coating so that the solvent is not substantially contained. The drying method is not particularly limited.

The thickness of the ultraviolet curable coating agent is 2 to 300 μm for coating and 10 to 10 μm for bonding.
It is preferably about 400 μm. When a solvent is used, the thickness is adjusted to this thickness after drying. When the thickness is small, a hardened layer having high strength cannot be obtained, and a sufficient effect of improving surface hardness and adhesiveness cannot be obtained. When the thickness is too thick, drying and curing reactions take time, resulting in poor productivity. In addition, when the curing is insufficient and the hardness is low, the cured layer may lack flexibility and crack.

The painted surface needs to be sufficiently dried if necessary. If the coating is cured while containing a large amount of solvent, cracks are likely to be generated in the coating film, and it also becomes a cause that a coating film with high hardness cannot be obtained. The drying temperature and time required to substantially remove the solvent depends on the type of solvent used,
Although it depends on the shape of the bonding surface, the conditions may be determined so that the substrate is not more than 120 ° C. and sufficiently dried so that the substrate is not thermally deformed. Specifically, 60-1
Drying at 20 ° C. for about 3 to 60 minutes is common. After drying at a high temperature, it is preferable to perform cooling at room temperature for about 10 seconds to 10 minutes, and then cool to almost room temperature. In addition,
If no solvent is used, drying is not required.

Thereafter, by irradiating ultraviolet rays from a light source such as a high-pressure mercury lamp that efficiently generates ultraviolet rays, curing occurs in a short time, and a cured layer having high hardness is formed. The irradiation amount of the ultraviolet ray varies depending on the reactivity of the photopolymerizable monomer and the photopolymerization initiator, but usually, in the case of a high-pressure mercury lamp of 80 W / cm, curing can be performed in a short time of about 5 to 10 seconds.

The above-mentioned coat layers are not limited to use on the information recording medium substrate comprising the specific aromatic vinyl polymer hydrogenated product of the present invention. The provision of the article on the information recording medium substrate is preferable because the reliability of the information recording medium can be further improved. Furthermore, these coating agents have good slippage on the surface when applied to a molded product, have an excellent antistatic effect, and are excellent in effects such as being printable. It is also useful as a protective coating agent, a hard coating agent, and the like for general molded articles such as polymer hydrogenated products and other optical components using a vinyl cyclic hydrocarbon resin.

By adopting such a method, an information recording medium substrate having an unprecedented superior coating layer, that is, (1) a vinyl-based cyclic hydrocarbon resin, having an adhesion strength of 90% in a cross-cut peel test. And an information recording medium substrate having a protective coat layer having a surface hardness (pencil hardness) of 2H or more, and (2) a protective coat layer comprising a reactive monomer and a reactive monomer on the surface of the substrate. An information recording medium substrate according to (1), which is formed by applying and / or irradiating an ultraviolet ray curable coating agent comprising a reactive oligomer and a photopolymerization initiator, and (3) an ultraviolet ray curable coat The agent is a long-chain aliphatic monofunctional acrylate monomer, an alicyclic monofunctional acrylate monomer, and an alicyclic 2
The information recording medium substrate according to (1) or (2), which contains at least 40% by weight of at least one monomer selected from functional acrylate monomers.

(Surface Treatment) In the present invention, the main object of the present invention is to improve the adhesion of the recording film layer or the coat layer to the substrate by plasma treatment, corona discharge treatment, active gas treatment, or the like. Various conventionally known surface treatments such as a solvent etching treatment, a microsand blast treatment, and a chemical etching treatment may be performed.

(Other Steps) For example, in the case of a digital video disk or a laser disk, it is also possible to use two disks each having a half thickness and stick the disks together so that the recording film layer is on the inside. . It is also possible to print a label or the like on the coating agent by a screen printing method or the like. Further, the steps specified in the manufacturing process of the present invention need to be performed in order, but steps other than these steps can be added.

[0122] By the above processes the information recording medium, the information recording medium is manufactured.
Examples of the information recording medium according to the present invention include an optically readable information recording medium. Specifically, non-rewritable ones, such as music CDs, CD-ROMs, laser disks, etc., utilizing changes in reflected light due to minute irregularities, CD-Rs, WORM (write-once optical disks), MOs
(Rewritable optical disk; magneto-optical disk), MD
(Mini disk), DVD (digital video disk)
For example, there is a type which can be additionally written or rewritten using a change in reflectance due to a functional dye or a phase change. In particular,
For example, for an optical information recording medium disk having a conductive film layer made of aluminum, gold, iron or the like and a compound containing these metal atoms as a reflective film layer, a corona is formed after forming the conductive film layer. There was a danger of discharge when performing the discharge treatment, and such a treatment was impossible. However, by employing the manufacturing method of the present invention, there is no scorch or burn due to the discharge, and the adhesive strength between the respective layers is reduced. Can be improved, which is preferable.

Optical parts The molding material of the present invention has sufficiently small birefringence, excellent mechanical strength, and excellent moisture resistance and molding workability. It is suitable for all optical components that require the following. Examples of optical components that can be used for the molding material of the present invention include optical lenses, prisms, mirrors, medical test cells,
Optical components that can be formed of a conventionally known plastic, such as a light guide plate and an optical film, may be used. Specifically, all light-transmitting lenses such as an imaging lens of a camera, an imaging lens of a video camera, a microscope lens, an endoscope lens, a telescope lens, a binocular lens, an eyeglass lens, a magnifying lens, a CD,
CD-ROM, WORM (write-once optical disk), MO
(Rewritable optical disk; magneto-optical disk), MD
It is used for a wide range of applications, such as pickup lenses for optical disks such as (mini-discs), fθ lenses for laser beam printers, laser scanning lenses such as sensor lenses, and finder prism lenses for cameras. In addition, the aforementioned absorbents, dyes, and pigments are blended to mix optical lenses such as infrared sensor lenses, autofocus lenses, and bandpass filter lenses; optical mirrors; prisms; light guide plates such as liquid crystal displays, and blood test cells for medical use. Various inspection cells; examples include optical films such as polarizing films, retardation films, and light diffusion films.

The molded product of the present invention is also suitable as various medical transparent parts that require repeated steam sterilization under severer conditions. Specifically, liquid injection containers, ampules, prefilled Liquid or powder or solid drug containers such as syringes, infusion bags, solid drug containers, eye drop containers, and dropper containers; sample containers such as sampling test tubes for blood tests, blood sampling test tubes, and sample containers; syringes Medical instruments such as medical instruments; sterile containers used for sterilization of medical instruments and the like; medical optical components such as plastic lenses for medical tests and the like. The molding material of the present invention is also suitable for applications such as insulating materials and semiconductor processing equipment used in the field of electronic appliances.

[0125]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Production Examples, Examples, and Comparative Examples. Parts and percentages in these examples are on a weight basis unless otherwise specified. Various physical properties were measured according to the following methods. (1) The molecular weight was measured by GPC using toluene as a solvent, and the weight average molecular weight (Mw) in terms of standard polystyrene was determined. (2) The molecular weight distribution is measured by GPC using toluene as a solvent, and the weight average molecular weight (Mw) in terms of standard polystyrene.
And the number average molecular weight (Mn) are determined, and the weight average molecular weight (M
w) and the number average molecular weight (Mn) ratio (Mw / Mn) was calculated. (3) The amount of components having a molecular weight of 10,000 or less was measured by GPC using toluene as a solvent, and determined as the integrated amount of components having a molecular weight (M) of 10,000 or less in terms of standard polystyrene. (4) The hydrogenation rate of the aromatic ring was calculated by measuring ¹ H-NMR. (5) The birefringence value of the optical disk substrate was evaluated by the birefringence value at a position 25 mm from the center of the optical disk substrate having a diameter of 85 mm. The birefringence value was measured using a polarizing microscope (Nikon; 546n).
m Senalmon Compensator). Evaluation,
When the birefringence value is 5 nm or less, ◎
The case where it was 10 nm or less was evaluated as ○, and the case where it exceeded 10 nm was evaluated as x.

(6) The bending strength is 127 mm in length and 1 in width.
A 2.7 mm, 3 mm thick injection molded test piece
Based on STM D790, it was measured with a strograph (V10-B, manufactured by Toyo Seiki Seisaku-sho, Ltd.). The evaluation was ◎ when the yield point strength or breaking strength was 500 kgf / cm ² or more, and the breaking strength was less than 500 kgf / cm ² .
場合 when it is 00 kgf / cm ² or more, and the breaking strength is 40
A case of less than 0 kgf / cm ^{2 was} evaluated as x. (7) In observing the surface state of the optical disk substrate, the surface on the signal pattern side was observed with an optical microscope at a magnification of 100. (8) Observation of surface defects on the optical disk substrate was performed by examining the surface on the signal pattern side with an AFM (atomic force microscope; manufactured by Seiko Denshi Kogyo; SPI3700 / SPA-250).
Fifty μm × 5 μm surface portions were observed at 50 locations, and the number of concave defects having a length or width of 0.3 μm or more and a depth of 10 nm or more was measured. (9) In the high-temperature high-humidity test I, the optical disk substrate was kept in an environment of constant temperature and humidity at 50 ° C. and 80% relative humidity for 100 hours, and was rapidly taken out to a room temperature environment (outside the tester). After being left in a room for one hour, the light transmittance at a wavelength of 830 nm was measured. The results were determined by the difference in light transmittance between before and after holding at high temperature and high humidity. (10) High-temperature and high-humidity test II is a high-temperature and high-humidity test I by changing the conditions in a constant-temperature and constant-humidity tester to 60 ° C. and 90% relative humidity.
The same was done.

(Production Example 1) (Production of hydrogenated product A of aromatic vinyl polymer) In a stainless steel reactor equipped with a stirrer sufficiently dried and purged with nitrogen, 960 parts of dehydrated cyclohexane, styrene monomer 240 parts and 3.81 parts of dibutyl ether were charged, and 0.65 part of an n-butyllithium solution (15% hexane solution) was added with stirring at 40 ° C. to initiate polymerization. After polymerization for 3 hours under the same conditions, 1.26 parts of isopropyl alcohol was added to stop the reaction. When the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the produced aromatic vinyl polymer a were measured, Mw = 180,000, Mw / Mn = 1.04,
The content of components having a molecular weight of 10,000 or less was 0.0%. The component content of 0.0% indicates that the component content having a molecular weight of 10,000 or less is below the detection limit (the same applies hereinafter).

Next, 1200 parts of the polymerization solution containing the above-mentioned aromatic vinyl polymer a was transferred to a pressure-resistant reaction vessel equipped with a stirrer, and a nickel-diatomaceous earth catalyst (manufactured by Nikki Chemical Co., Ltd .;
N113, nickel carrying amount 40%) 24 parts were added and mixed. After completion of the charging, the inside of the reaction vessel was replaced with hydrogen gas, and hydrogen was supplied at 150 ° C. while stirring to obtain a pressure of 70%.
While maintaining the pressure at kg / cm ² , a hydrogenation reaction was performed for 6 hours. After the completion of the hydrogenation reaction, the hydrogenation catalyst was removed from the reaction solution by filtration. After adding and diluting 1200 parts of cyclohexane, the filtrate was further filtered through a filter having a pore size of 1 μm in an environment of a cleanliness class 1000 to remove foreign substances. This filtrate was filtered through a filter having a pore size of 1 μm under an environment of a cleanliness class of 1,000, 9000.
The mixture was poured into isopropanol to precipitate a hydrogenated product A of an aromatic vinyl polymer. After the hydrogenated product A was separated by filtration, the product was dried at 100 ° C. for 48 hours using a reduced-pressure drier to recover the hydrogenated product A of the aromatic vinyl polymer. The physical properties of the obtained hydrogenated product A were Mw = 153,000, Mw
/Mn=1.09, content of components having a molecular weight of 10,000 or less = 0.0%, and hydrogenation rate was 100.0%.

(Production Example 2) (Production of hydrogenated product B of aromatic vinyl polymer) 16.8 parts of nickel-diatomaceous earth catalyst, hydrogenation reaction temperature 160 ° C, pressure 60 kg / cm ² , reaction time Was carried out in the same manner as in Production Example 1 except that the reaction time was changed to 8 hours, to produce a hydrogenated aromatic vinyl polymer B. The obtained hydrogenated product B
Have physical properties Mw = 122,000 and Mw / Mn = 1.1.
7. The content of components having a molecular weight of 10,000 or less was 0.1%, and the degree of hydrogenation was 99.9%.

(Production Example 3) (Production of hydrogenated product C of aromatic vinyl polymer) Dibutyl ether was 3.36 parts, and n-butyllithium solution (hexane solution containing 15%) was 0.57 parts. Except for the above, an aromatic vinyl polymer c was produced in the same manner as in Example 1. When the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the aromatic vinyl polymer c were measured, Mw = 204,000, Mw / Mn = 1.10,
The content of components having a molecular weight of 10,000 or less was 0.0%.

Next, the obtained aromatic vinyl polymer c
1200 parts of the contained polymerization solution was transferred to the same reaction vessel as in Example 1, and the same nickel-diatomaceous earth catalyst 24 as in Example 1 was used.
Parts were added and mixed. Hydrogenated aromatic vinyl polymer C was produced in the same manner as in Production Example 1 except that the hydrogenation reaction temperature was 160 ° C. and the reaction time was 8 hours. The physical properties of the obtained hydrogenated product C were Mw = 152,000, Mw / Mn.
= 1.26, content of components having a molecular weight of 10,000 or less = 0.
The degree of hydrogenation was 99.4%.

(Production Example 4) (Production of hydrogenated product D of aromatic vinyl polymer) The pressure of the hydrogenation reaction was 50 kg / cm ² , and the reaction time was 1
A hydrogenated aromatic vinyl polymer D was produced in the same manner as in Production Example 3 except that the time was 0 hour. The physical properties of the obtained hydrogenated product D were Mw = 140,000 and Mw / Mn = 1.
67, the content of components having a molecular weight of 10,000 or less = 1.2%,
The hydrogenation rate was 99.9%.

(Production Example 5) (Production of hydrogenated product E of aromatic vinyl polymer) Nickel-alumina catalyst (manufactured by JGC Chemicals; N163, nickel carrying amount 40) instead of nickel-diatomaceous earth catalyst
% By weight), the hydrogenation reaction temperature was 230 ° C., and the pressure was 45 kg / cm ^2, and a hydrogenated aromatic vinyl polymer E was produced in the same manner as in Production Example 3. The physical properties of the obtained hydrogenated product E were Mw = 132,000, M
The w / Mn was 1.82, the content of components having a molecular weight of 10,000 or less was 2.1%, and the hydrogenation ratio was 99.0%.

(Production Example 6) (Production of hydrogenated product F of aromatic vinyl polymer) In the same reactor as in Example 1, dehydrated cyclohexane 280 was added.
Parts, 280 parts of dehydrated toluene and 240 parts of styrene monomer were charged, and while stirring at 40 ° C., 0.12 parts of azobisisobutyronitrile was added to initiate polymerization. The temperature of the reaction system was set to 70 ° C., and polymerization was performed for 24 hours. Weight average molecular weight of the aromatic vinyl polymer f produced after the reaction (M
w) and the molecular weight distribution (Mw / Mn) were measured.
w = 161,000, Mw / Mn = 2.30, and the content of components having a molecular weight of 10,000 or less = 0.8%.

The solution of the polymer f was added to dehydrated cyclohexane 40
0 part was added for dilution, and 28.8 parts of the same nickel-alumina catalyst as used in Production Example 5 was added and mixed. A hydrogenated aromatic vinyl polymer F was produced in the same manner as in Production Example 1 except that the hydrogenation reaction temperature was 230 ° C., the pressure was 45 kg / cm ² , and the reaction time was 8 hours. The physical properties of the obtained hydrogenated product F were Mw = 116,000 and Mw / Mn =
2.63, content of components having a molecular weight of 10,000 or less = 3.4
% And the hydrogenation rate were 98.1%.

(Production Example 7) (Production of hydrogenated product G of aromatic vinyl polymer) Except that 0.10 parts of azobisisobutyronitrile was used, the reaction temperature was 60 ° C, and the reaction time was 48 hours. In the same manner as in Production Example 6, an aromatic vinyl polymer g was produced. When the weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the aromatic vinyl polymer g were measured, Mw = 195,00
0, Mw / Mn = 1.80, content of components having a molecular weight of 10,000 or less = 0.5%.

A ruthenium-carbon catalyst (manufactured by NE Chemcat) in place of the nickel-alumina catalyst;
(Amount of ruthenium supported: 5%) was added and mixed, and a hydrogenated aromatic vinyl polymer G was produced in the same manner as in Production Example 6 except that the hydrogenation reaction temperature was 170 ° C. and the reaction time was 10 hours. did. The physical properties of the obtained hydrogenated product G were Mw =
79,000, Mw / Mn = 1.65, molecular weight 10.0
Component content of not more than 00 = 1.9%, hydrogenation rate 98.5%
Met.

(Production Example 8) (Production of hydrogenated product H of aromatic vinyl polymer) The hydrogenation reaction temperature was set at 160 ° C, and the pressure was 30 kg / cm.
^The hydrogenation was performed in the same manner as in Production Example 5 except that the reaction time was increased to 5 hours, the reaction time was increased to 60 kg / cm ² and the reaction time was increased to 5 hours to produce a hydrogenated aromatic vinyl polymer H. did. The physical properties of the obtained hydrogenated product H were Mw = 10
6,000, Mw / Mn = 1.58, molecular weight 10,000
The component content of 0 or less = 2.4%, and the hydrogenation rate was 99.6%.

(Production Example 9) (Production of hydrogenated product I of aromatic vinyl polymer) Hydrogenation was carried out in the same manner as in Production Example 2 except that the hydrogenation reaction temperature was changed to 5 hours. Polymer hydride I was prepared. The physical properties of the obtained hydrogenated product I were Mw = 1.
37,000, Mw / Mn = 1.12, molecular weight 10.0
Component content of 00 or less = 0.1%, hydrogenation rate is 95.0%
Met.

Table 1 shows the physical properties of the hydrogenated polymer obtained in the above Production Examples.

[0141]

[Table 1]

(Examples 1 to 4) A soft polymer (manufactured by Asahi Kasei Corporation; Tuftec H1052) was added to 100 parts of each of the aromatic vinyl polymer hydrogenated products A to D produced in Production Examples 1 to 4.
0.1 parts and 0.1 part of an antioxidant (Ciba Geigy; Irganox 1010) were added, and a twin screw kneader (Toshiba Machine; TEM-35B, screw diameter 37 mm, L / L
D = 32, screw rotation speed 150 rpm, resin temperature 2
The mixture was kneaded at 40 ° C. at a feed rate of 15 kg / hour) and extruded into strands. This was cooled with water, cut with a pelletizer, and pelletized.

The obtained four types of pellets were dried at 70 ° C. for 2 hours using a hot-air drier through which air was circulated to remove water, and were injected with an injection molding machine (Sumitomo Heavy Industries, Ltd .; DISC).
Using -3), injection molding was performed at a resin temperature of 300 ° C. and a mold temperature of 100 ° C. using a mold having an optical disk stamper attached thereto to obtain an 85 mmφ optical disk substrate.

Each of the obtained optical disk substrates had a birefringence value of 5 nm or less, and the evaluation was ◎. Microscopic observation of the surface on which the signal pattern was formed by the stamper revealed no abnormality. When the surface on which the signal pattern was formed was observed by AFM, no concave defect having a length or width of 0.3 μm or more and a depth of 10 nm or more was found. The optical disc substrate was subjected to high temperature and high humidity tests I and II to measure the change in light transmittance, but no change was observed. Table 2 summarizes the evaluation results.

Using the above four types of pellets, an injection molding machine (manufactured by FANUC; AUTOSHOTO MODEL)
30A), resin temperature 300 ° C., mold temperature 100 ° C.
11. Injection molding was performed with a length of 127 mm and a width of 12.
A test piece having a thickness of 7 mm and a thickness of 3 mm was formed. The bending strength of the test piece was 500 kgf / cm ² or more, and the evaluation was ◎.
Table 2 shows the evaluation results.

(Example 5) A poly (oxy) reacting as a partial ether compound at a ratio of two molecules of nonylphenol to two molecules of glycidol per 100 parts of the hydrogenated product A of the aromatic vinyl polymer produced in Production Example 1 -2-hydroxyl trimethylene) nonylphenyl ether HO
[CH ₂ CH (OH) CH ₂ O] _n C ₆ H ₄ C ₉ H ₁₉
(N is a natural number, the average n of all molecules is 2) 0.5 part,
Anti-aging agent (Irganox 101 manufactured by Ciba-Geigy)
0) 0.1 part was added and kneaded with a twin-screw kneader in the same manner as in Example 1, extruded and pelletized.

The same evaluation as in Example 1 was performed using the obtained pellets. The birefringence value of the obtained optical disk substrate was 5 nm or less, and the evaluation was ◎. No abnormalities were observed by microscopic observation of the surface. No defects were found by AFM observation. High temperature and high humidity test I and I
No change in light transmittance due to I was observed. The bending strength of the test piece was 500 kgf / cm ² or more, and the evaluation was ◎. Table 2 shows the results.

(Example 6) A poly (nonylphenol) molecule reacting as a partial ether compound at a ratio of 2.5 molecules of glycidol per 100 parts of the hydrogenated product B of the aromatic vinyl polymer produced in Production Example 2 was used. (Oxy-2
- hydroxyl trimethylene) nonylphenyl ether _{HO [CH 2 CH (OH)} CH 2 O] n C 6 H 4 C 9 H
₁₉ (n is a natural number, the average n of all molecules is 2.5)
0.5 part and 0.1 part of an antioxidant (Irganox 1010 manufactured by Ciba Geigy) were added, and the mixture was kneaded with a twin-screw kneader in the same manner as in Example 1, extruded and pelletized.

The same evaluation as in Example 1 was performed using the obtained pellets. The birefringence value of the obtained optical disk substrate was 5 nm or less, and the evaluation was ◎. No abnormalities were observed by microscopic observation of the surface. No defects were found by AFM observation. High temperature and high humidity test I and I
No change in light transmittance due to I was observed. The bending strength of the test piece was 500 kgf / cm ² or more, and the evaluation was ◎. Table 2 shows the results.

Example 7 One molecule of behenic acid and one molecule of glycerol were used as a partial ester compound per 100 parts of the hydrogenated product C of the aromatic vinyl polymer produced in Production Example 3.
Behenic acid monoglyceride [CH ₃ (CH ₂ ) ₂₀ COOCH ₂ (CHOH) CH reacting at a molecular rate
₂ OH] 0.5 parts were added an antioxidant (manufactured by Ciba-Geigy Irganox 1010) 0.1 parts were kneaded in the same biaxial kneader as in Example 1, extruded, and pelletized.

The same evaluation as in Example 1 was performed using the obtained pellets. The birefringence value of the obtained optical disk substrate was 5 nm or less, and the evaluation was ◎. No abnormalities were observed by microscopic observation of the surface. No defects were found by AFM observation. High temperature and high humidity test I and I
No change in light transmittance due to I was observed. The bending strength of the test piece was 500 kgf / cm ² or more, and the evaluation was ◎. Table 2 shows the results.

(Example 8) Per 100 parts of hydrogenated product D of the aromatic vinyl polymer produced in Production Example 4, one molecule of stearic acid was reacted as a partial ester compound at a ratio of one molecule of pentaerythritol. Pentaerythritol monostearate [CH ₃ (CH ₂ ) ₁₆ COO
0.7 parts of CH ₂ C (CH ₂ OH) ₄ ] and 0.1 parts of an antioxidant (Irganox 1010 manufactured by Ciba Geigy) were added, kneaded with a twin-screw kneader in the same manner as in Example 1, and extruded. Pelletized.

The same evaluation as in Example 1 was performed using the obtained pellets. The birefringence value of the obtained optical disk substrate was 5 nm or less, and the evaluation was ◎. No abnormalities were observed by microscopic observation of the surface. No defects were found by AFM observation. High temperature and high humidity test I and I
No change in light transmittance due to I was observed. The bending strength of the test piece was 500 kgf / cm ² or more, and the evaluation was ◎. Table 2 shows the results.

(Examples 9 to 12) The hydrogenated products A of the aromatic vinyl polymers produced in Production Examples 1, 2, 5 and 8
For each 100 parts of B, E and H, only 0.1 part of an antioxidant (Irganox 1010 manufactured by Ciba Geigy) was added, and kneaded with a twin-screw kneader in the same manner as in Example 1.
Extruded and pelletized.

The same evaluation as in Example 1 was performed using the obtained pellets. Table 2 shows the results.

(Comparative Examples 1 to 3) Antioxidants (manufactured by Ciba Geigy Co., Ltd.) were added to 100 parts of each of the hydrogenated products F, G and I of the aromatic vinyl polymers produced in Production Examples 6, 7 and 9. Irganox 1010) Only 0.1 part was added, kneaded with a twin-screw kneader in the same manner as in Example 1, and extruded.
Pelletized.

The same evaluation as in Example 1 was performed using the obtained pellets. The birefringence value of the obtained optical disk substrate was 8 nm in Comparative Example 1 and 5 nm or less in Comparative Example 2, and the evaluation was お よ び and ◎. In Comparative Example 3, the evaluation was 12 nm and the evaluation was ×. Microscopic observation of the surface showed no abnormality. No defects were found in Comparative Examples 2 and 3 by AFM observation, but five defects were found in Comparative Example 1. No change in light transmittance was observed in the high-temperature and high-humidity test I, but a decrease in light transmittance of 9 to 20% was observed in the more severe high-temperature and high-humidity test II. Comparative Example 3
Was 500 kgf / cm ² or more, and the evaluation was 、. However, in Comparative Examples 1 and 2, both evaluations were less than 400 kgf / cm ² and the evaluation was ×. Table 2 shows the results.

[0158]

[Table 2]

(Example of molding by special molding method) In the present invention, as a molding method of the molding material described in the above detailed description, a method of molding a substrate with a low oxygen concentration in an injection molding machine at the time of molding, A method of forming a substrate after performing a process for reducing the concentration of dissolved oxygen in a molding material before molding can be used. Examples will be described below.

(Example 13) (Molding in Nitrogen Gas Atmosphere) Nitrogen gas having an oxygen concentration of 0.1% by volume or less was supplied at a rate of 10 liter / min. An optical disk substrate was obtained in the same manner as in Example 12, except that the supply was carried out at a flow rate of. The results of evaluating the properties of the obtained optical disk substrate are shown below. The evaluation was performed using the same evaluation method as in Examples 1 to 12, and the description of the evaluation results was also based on the same criteria as in Examples 1 to 12. (The same applies to Examples 14 to 16 below.) The mechanical strength (bending strength) was [［]. -The result of microscopic observation was [no abnormality]. The result of AFM observation was the number of defects [0/50]. Further, while the molecular weight of the resin of the optical disk substrate after molding in Example 12 was Mw = 55,000 and Mw / Mn = 2.08, in the case of this Example, even after molding, Mw = 55,000.
The molecular weight distribution was 78,000, and the molecular weight distribution was Mw / Mn = 1.82, and the decrease in molecular weight after molding was small.

(Example 14) (Preliminary drying under a nitrogen atmosphere) The resin pellets before molding were filled with an oxygen concentration of 0.1% by volume.
Using a hot air dryer filled with the following nitrogen gas, 100
An optical disc substrate was obtained in the same manner as in Example 12 except that the resin pellets were dried at 3 ° C. for 3 hours, and allowed to cool in the air at room temperature for 1 hour and then supplied to a hopper of a molding machine. . -The mechanical strength (bending strength) was [［]. -The result of microscopic observation was [no abnormality]. The result of AFM observation was the number of defects [0/50]. The molecular weight of the resin of the optical disk substrate after molding is Mw =
76,000, and the molecular weight distribution was Mw / Mn = 1.82.

(Example 15) (Preliminary drying under reduced pressure) The resin pellets before molding were subjected to 1 ton using a vacuum dryer.
The optical disc substrate was dried in the same manner as in Example 12 except that the resin pellets were dried at rr and 100 ° C. for 2 hours, allowed to cool in air at room temperature for 1 hour, and then supplied to a hopper of a molding machine. I got -The mechanical strength (bending strength) was [［]. -The result of microscopic observation was [no abnormality]. The result of AFM observation was the number of defects [0/50]. The molecular weight of the resin of the optical disk substrate after molding is Mw =
79,000, molecular weight distribution Mw / Mn = 1.78.

(Example 16) (Pre-drying under nitrogen + molding under nitrogen) The resin pellets before molding were prepared such that the inside had an oxygen concentration of 0.1% by volume.
Using a hot air dryer filled with the following nitrogen gas, 100
C. for 3 hours, immediately supply the resin pellets taken out of the dryer to a hopper of a molding machine, and further feed a nitrogen gas having an oxygen concentration of 0.1% by volume or less to the hopper of the injection molding machine at a rate of 10 · / min. An optical disk substrate was obtained in the same manner as in Example 12, except that the supply was carried out at a flow rate of. -The mechanical strength (bending strength) was [［]. -The result of microscopic observation was [no abnormality]. The result of AFM observation was the number of defects [0/50]. The molecular weight of the resin of the optical disk substrate after molding is Mw =
91,000, molecular weight distribution Mw / Mn = 1.65.

(Example of use of coating agent) In the present invention,
When using the obtained substrate as an information recording medium, it is preferable to use a protective coating agent. Hereinafter, an example in which the above-mentioned preferable protective coating agent is used for the optical disk substrate of the present invention will be described together with comparative examples. The method for evaluating the protective coat film is described below.

(11) Surface electric resistance value is JIS K-6
911. (12) The evaluation of curing shrinkage is performed by applying a protective coating agent to one side of the disk substrate, drying the coating, irradiating the substrate with ultraviolet light, and curing the disk substrate. When fixed, the angle between the horizontal plane and the straight line connecting the outermost periphery of the substrate and the center of the substrate was measured, and the degree of cure shrinkage was indicated by the angle. (13) Surface hardness (pencil hardness) is JIS K-5400
Was measured at a load of 1 kg. (14) Adhesion evaluation (cross-cut peeling test): 11 cuts each in the vertical and horizontal directions were made at intervals of 1 mm with a cutter knife from the top of the protective coat layer formed on the substrate surface to obtain a 1-mm square cross-cut of 100. Make individual pieces and attach cellophane adhesive tape (Sekisui Chemical Co., Ltd.). Next, the adhesive tape was peeled off in the direction of 90 °, and the number of eyes where the protective coat layer was not peeled was%.
Indicated by (15) The high-temperature and high-humidity test is performed in a constant temperature and humidity tester 65
After leaving the optical disk for 500 hours in an environment of 90 ° C. and 90% relative humidity, the optical disk was taken out of the tester, and the state of the metal recording film was observed and evaluated.

Example 17 n-butyl acrylate 1
0 parts by weight. 28 parts by weight of isoamyl acrylate, 30 parts by weight of trimethylolpropane triacrylate, 42 parts by weight of dipentaerythritol hexaacrylate, and a photopolymerization initiator (manufactured by Ciba Geigy, Irgacure 65
1) 5 parts by weight are mixed, and 2 parts by weight of a nonionic antistatic agent (manufactured by Toho Kagaku, Anstics SA-300); and a fluorinated nonionic surfactant (Fluorad FC-171, manufactured by Sumitomo 3M) Was added so as to be 500 ppm to prepare an ultraviolet curable coating agent.

On the substrate obtained in Example 1, a recording film layer was formed using ILC-3000 manufactured by Nidec Anelva. The configuration of the recording film layer is SiN 100 nm, TbFe
Co is 30 nm, SiN is 40 nm, and Al is 40 nm. The recording film layer was not provided with a width of 1.0 mm at the outermost periphery and a width of 2.0 mm outside the groove at the inner periphery.

The obtained ultraviolet curable coating agent was applied to the substrate obtained above using a spin coater (5000 rpm, 10 seconds), left at room temperature for 10 minutes, and dried sufficiently. The thickness of the dried ultraviolet curable coating agent film was 6 μm. The substrate was irradiated with ultraviolet light from a high-pressure mercury lamp of 80 mW (peak irradiation intensity on the substrate surface: 150 mW / cm).
² , integrated light amount 1500 mJ / cm ² , irradiation time 10 seconds)
To cure the ultraviolet curable coating agent to form a hard coat layer.

The surface electric resistance was 9.1 × 10 ¹² Ω. The degree of cure shrinkage was 3 milliradians, and the hardness of the coated substrate surface was 3H in pencil hardness. As a result of the warp stress test, no crack was generated. The result of the cross-cut peel test was 98%, and was 94% even after a high-temperature high-humidity endurance test at 80 ° C., 90% RH and 500 hours. No abnormality was observed in the recording film layer after the high temperature and high humidity test.

(Example 18) n-butyl acrylate 5
Parts by weight. 32 parts by weight of isoamyl acrylate, 20 parts by weight of neopentyl glycol diacrylate, 48 parts by weight of dipentaerythrol hexaacrylate, and 5 parts by weight of a photopolymerization initiator (Irgacure 651 manufactured by Ciba Geigy) were mixed, and further, a fluorine-based nonion was mixed. 5 surfactant (Sumitomo 3M, Florade FC-171)
Add to 00ppm, adjust the coating agent,
A coat layer was formed in the same manner as in Example 16 using the ultraviolet curable coating agent. Surface electric resistance value is 3.3 × 1
0 ¹⁵ Ω. The curing shrinkage was 4 milliradians, and the hardness of the coated substrate surface was 3H in pencil hardness. No crack was generated when a warp stress was applied to the substrate. The result of the cross-cut peel test was 95%, 80 ° C, 9
0% RH, 94% even after high-temperature, high-humidity endurance test for 500 hours
Met. No abnormality was observed in the recording film layer after the high temperature and high humidity test.

Comparative Example 4 A coat layer was formed on a substrate in the same manner as in Example 16 except that a commercially available acrylic coating agent (SD-17, manufactured by Dainippon Ink and Chemicals, Inc.) was used as the ultraviolet-curing coating agent. did.

The surface electric resistance was 5.3 × 10 ¹⁵ Ω. The curing shrinkage was 3 milliradians, and the hardness of the coated substrate surface was 2H in pencil hardness. As a result of the warp stress test, no crack was generated on the substrate. The result of the cross-cut peel test was 61%, and further, 80 ° C., 90% RH, 500%
After 21 hours of high temperature and high humidity endurance test, it was 21%. After the high-temperature and high-humidity test, it was confirmed that corrosion occurred in the recording film layer.

[0173]

According to the present invention, there is provided a molding material which exhibits a sufficiently small birefringence and is suitable as an information recording medium substrate having excellent mechanical strength, and an information recording medium substrate formed by molding the molding material. You. In addition, it can exhibit a sufficiently small birefringence, and is excellent in mechanical strength, and can be formed into a molded article excellent in moisture resistance such as prevention of white turbidity and durability of a recording film in a high temperature and high humidity environment, surface smoothness, and the like. A novel aromatic vinyl polymer hydrogenated product suitable as a molding material for an information recording medium substrate having excellent moldability and a resin composition comprising the aromatic vinyl polymer hydrogenated product are provided. The information recording medium substrate of the present invention has a small birefringence, mechanical strength,
It is particularly useful as a substrate for a magneto-optical disk, a digital video disk (DVD), or the like in the field of an information recording medium that requires moisture resistance and moldability. Further, the novel substance of the present invention has excellent properties as a molding material, so that it can be used not only in the information recording medium field but also in the optical field, (medical products,
It is also useful in the container field (for cosmetics, etc.), electrical insulation and other fields.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Toshihide Murakami 1-2-1 Yoko, Kawasaki-ku, Kawasaki-shi, Kanagawa F-term in the Zeon Corporation General Development Center 4J002 BB033 BB123 BB173 BC031 BC051 BC061 BC063 BC071 BC081 BC091 BC111 BD043 BE023 BE063 BF023 BG103 BG133 CH022 CH023 CH052 DD036 DE096 DE136 DE236 DF016 DG046 DH046 DK006 FD013 FD016 FD202 FD203 FD206 4J100 AA02Q AA03Q AB02P AB03P AB04P AB07P AJ02Q AK32Q AL03Q AM02Q AM03Q AM48Q AS01Q AS02Q AS03Q AS04Q BB01P BB01Q BB07P CA04 CA31 DA01 DA04 FA03 HA05 HB17 HC84 HC89 HC90 5D029 KA13 KC07

Claims (5)

[Claims] An aromatic vinyl polymer obtained by hydrogenating an aromatic vinyl polymer has a hydrogenation rate of an aromatic ring of 97% or more, and a ratio (Mw / Mw) between a weight average molecular weight (Mw) and a number average molecular weight (Mn).
Mn) is 2.0 or less and the weight average molecular weight (Mw) is 10
000-300,000 and a molecular weight (M) of 1
A hydrogenated polymer having a content of not more than 000 and not more than 2% by weight based on the total weight of the polymer. 2. A resin composition comprising the hydrogenated polymer according to claim 1 and an anti-clouding agent. 3. A hydrogenation rate of an aromatic ring obtained by hydrogenating an aromatic vinyl-based polymer is 97% or more, and a ratio (Mw / Mw) between a weight average molecular weight (Mw) and a number average molecular weight (Mn) is obtained.
A molding material for an information recording medium substrate comprising a hydrogenated polymer having a Mn of 2.0 or less and a weight average molecular weight (Mw) of 100,000 to 300,000. 4. A molding material comprising the hydrogenated polymer according to claim 1 or the resin composition according to claim 2. 5. An information recording medium substrate obtained by molding the molding material according to claim 3 or 4.