JP2002308923A - Isotactic polystyrene polymer, its hydrogenated product and their manufacturing methods - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an isotactic polystyrene polymer having isotacticity simply and highly controlled, its hydrogenated product and their manufacturing methods. SOLUTION: The method for manufacturing the isotactic polystyrene polymer comprises polymerizing styrene and, if required, a conjugated diene in the presence of an anionic polymerization initiator and a compound represented by formula (I) (wherein (n) is 1 or 2; R is hydrogen atom, a 1-12C aliphatic hydrocarbyl group or a 6-12C aromatic hydrocarbyl group; and M is an alkali metal other than lithium and beryllium or an alkaline earth metal).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an isotactic polystyrene-based polymer, a hydride thereof, and a method for producing the same. More particularly, the present invention relates to an isotactic polystyrene polymer whose degree of isotacticity is easily and highly controlled, a hydride thereof, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, development relating to stereoregular polymerization of polyolefins such as polystyrene and polypropylene has been actively carried out. This is because various physical properties such as heat resistance, toughness and moldability of the polymer can be drastically changed by controlling the three-dimensional structure.
Generally, dyad (two-chain steric structure of units derived from monomers) is used as an index to indicate the stereoregularity of polyolefin
Is used, the degree of isotacticity is represented by isotactic dyad (m), and the degree of syndiotacticity is represented by syndiotactic dyad (r). m and r have a relationship of m + r = 100%, and m> 50%
(R <50%) if isotactic, r> 50%
(M <50%) if syndiotactic, m = r =
If it is 50%, it is called atactic.

[0003] To date, the stereoregularity of polystyrene can be controlled to some extent by polymerization methods. For example, ordinary radical polymerization, cationic polymerization, or anionic polymerization yields about r to 55% polystyrene. In coordination polymerization using a Ziegler-Natta catalyst, m> 90% polystyrene (Natta, Maclom)
ol. Chem. 16, 213 (1955)). Further, in coordination polymerization using a metallocene catalyst, r>
90% polystyrene (Ishihara et al., Macl
omolecules, 21, 3356 (198
8)) is obtained. However, synthesis methods for isotactic polystyrene in which 90%>m> 50% are extremely limited. Specifically, the following methods have been proposed so far.

A method of polymerizing styrene at −30 ° C. using an initiator consisting of butyllithium and lithium hydroxide (Worsfold et al., Macromol. Chem.
65, 245 (1963)). A method of polymerizing styrene at −30 ° C. using an initiator consisting of butyllithium and lithium-t-butoxide (C
azzaniga et al., Macromolecules,
22, 4125 (1989)). A method of polymerizing styrene at 0 ° C. or lower using an initiator composed of lithium diphenylalkyl and lithium alkoxide (JP-A-11-80267). Polymerization of styrene using potassium naphthalene as an initiator (Uryu et al., J. Polym. Sci., P
oly. Chem. Ed. , Vol. 17, 2019 (197
9)).

[0005] Of these, the reaction at a low temperature is necessary, and as a result, the polymerization rate is extremely low.
Low productivity. In addition, the initiator is an extremely reactive reagent, and it is difficult to carry out industrially in terms of concentration determination and handling. Therefore, there is no practical method for synthesizing the above-mentioned isotactic polystyrene in the prior art, and its development has been desired. Conventionally, the degree of stereoregularity has depended on the type of initiator, and it has been impossible to freely control the degree, and development of such a method has been desired.

On the other hand, recently, it has been disclosed in Japanese Patent Publication No. 7-114030, that a hydride of a polystyrene-based polymer obtained by hydrogenating a polystyrene-based polymer can be suitably used as an engineering material such as an optical disk. 26
No. 68945, Japanese Patent No. 2730053, and the like. This resin is characterized by high light transmittance and very low birefringence and water absorption as compared with conventionally used polycarbonates. Although the three-dimensional structure of the polystyrene-based polymer hydride is mostly atactic, syndiotactic hydrogenated polystyrene (74% ≧ r ≧ 50.1%) and isotactic hydrogenated polystyrene (74% ≧ r ≧ 50) .1%) also in WO99 / 32528 and WO00 / 4905, respectively.
7 is disclosed.

[0007] Of these, there have been few methods for producing isotactic polystyrene as described above. Therefore, production of isotactic hydrogenated polystyrene is extremely difficult, and development of a simple production method has been desired.

[0008]

As is apparent from the prior art, an object of the present invention is to provide a simple method for producing an isotactic polystyrene-based polymer and a hydride thereof.

[0009]

In view of the prior art, the present inventors have paid attention to basic alkali metal compounds and alkaline earth metal compounds. Some of these compounds are, for example, WO
Although it is described in JP-A-00 / 34340 as one of Lewis bases capable of narrowing the molecular weight distribution during anionic polymerization, there is no example examined in detail. The present inventors have conducted intensive studies on the effect, and unlike other bases described as Lewis bases, basic alkali metal compounds and alkaline earth metal compounds have the effect of narrowing the molecular weight distribution. Did not. However, they have found that an isotactic polystyrene-based polymer can be obtained by adding a basic alkali metal compound or alkaline earth metal compound. Furthermore, the degree of isotacticity can be controlled by the amount of addition, the hydrogenation of the obtained isotactic polystyrene-based polymer yields a hydrogenated isotactic polystyrene-based polymer, The inventors have found that they have excellent properties and toughness and can be suitably used as optical materials such as optical disks, and have completed the present invention.

That is, the present invention provides an anionic polymerization initiator comprising a compound represented by the following formula (I):

[0011]

Embedded image

Wherein n is 1 or 2, R is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and M is Styrene and, if necessary, a conjugated diene in the presence of a compound represented by the formula (I), which is an alkali metal or an alkaline earth metal excluding lithium and beryllium): It is.

[0013] The present invention further includes: The process according to the invention, wherein M is potassium. 2. 3. A method for producing a hydrogenated isotactic polystyrene polymer, comprising hydrogenating the isotactic polystyrene polymer according to the invention or 1 in the presence of a hydrogenation catalyst. 3. The isotactic dyad of the styrene polymerization portion obtained by the production method according to the invention or 1 is 5 or less.
0.1% to 80% of an isotactic polystyrene-based polymer. 4. 50.1% of an isotactic dyad of a hydrogenated styrene polymerization part obtained by the production method described in 2
-80% isotactic polystyrene polymer hydride. 5. 5. An optical material mainly comprising the hydride of the isotactic polystyrene-based polymer according to 4. 4. An optical disk substrate mainly composed of the hydride of the isotactic polystyrene-based polymer described in 4.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

(Isotactic polystyrene-based polymer) The isotactic polystyrene-based polymer in the present invention is conjugated with styrene and, if necessary, conjugated with anionic polymerization initiator in the presence of the compound represented by the above formula (I). It is produced by polymerizing a diene.

The anionic polymerization initiator in the present invention is a metal belonging to Groups 1 and 2 of the periodic table and their organometallic compounds. Specifically, lithium, sodium, potassium, rubidium, cesium, francium, magnesium, calcium, strontium, barium, radium, methyllithium, ethyllithium, n-propyllithium,
iso-propyllithium, n-butyllithium, i
So-butyl lithium, sec-butyl lithium, cyclopentadienyl lithium, phenyl lithium, cyclohexyl lithium, methyl sodium, ethyl sodium, n-propyl sodium, iso-propyl sodium, n-butyl sodium, cyclopentadienyl sodium, dimethyl Examples include magnesium, dibutylmagnesium, bis (cyclopentadienyl) magnesium, dimethylcalcium, bis (cyclopentadienyl) calcium and the like. Of these, organolithium compounds and organomagnesium compounds are preferable from the viewpoint of availability and operability, and n-butyllithium and sec.
-Butyllithium, dibutylmagnesium are particularly preferred. These may be used alone or in combination of two or more.

Further, the above initiator is further activated,
An electron donating compound may be added for the purpose of improving the reaction rate, increasing the molecular weight, and preventing anion deactivation. The electron donating compound is a compound that can donate electrons to the metal of the initiator without impairing the function of the initiator, and is a compound containing an oxygen atom, a nitrogen atom, a sulfur atom, and a phosphorus atom. Specifically, ethers such as furan, tetrahydrofuran, diethyl ether, anisole, diphenyl ether, methyl-t-butyl ether, dioxane, dioxolane, dimethoxyethane, diethoxyethane, and the like; trimethylamine, triethylamine, tributylamine, tetramethylmethylenediamine, tetramethyl Ethylenediamine,
Tetraethylmethylenediamine, tetraethylethylenediamine, tetramethyl1,3-propanediamine, tetramethylphenylenediamine, diazabicyclo [2,
Tertiary amines such as 2,2] octane; thioethers such as dimethylsulfide, thiophene and tetrahydrothiophene; trimethylphosphine, triethylphosphine, tri-n-butylphosphine, triphenylphosphine, dimethylphosphinomethane, dimethylphosphinoethane; Tertiary phosphines such as dimethylphosphinopropane, diphenylphosphinomethane, diphenylphosphinoethane, and diphenylphosphinopropane can be exemplified. Of these, particularly preferred are tetrahydrofuran, dimethoxyethane, tetramethylethylenediamine, and diazabicyclo [2,2,2] octane. These may be used alone or in combination of two or more.

The amount of the electron-donating compound depends on the type of the initiator and the electron-donating compound.
0.1 to 100 mol, preferably 0.2 to 100 mol
It is 50 mol, more preferably 0.3 to 10 mol. If the amount is too small, the activating effect cannot be obtained, and if the amount is too large, the activating effect does not increase, and the electron donating compound is wasted.
However, this does not apply when an electron donating compound is used as a solvent.

In the present invention, an anionic polymerization initiator is represented by the following formula (I):

[0020]

Embedded image

(Wherein n is 1 or 2, R is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms or an aromatic hydrocarbon group having 6 to 12 carbon atoms, and M is Which is an alkali metal or alkaline earth metal excluding lithium and beryllium). R in the above formula (I) is preferably a hydrogen atom; a chain or cyclic group having 1 to 12 carbon atoms which may be substituted with an aliphatic or aromatic hydrocarbon group having 1 to 6 carbon atoms. Aliphatic hydrocarbon group; examples thereof include an optionally substituted aromatic hydrocarbon group having 6 to 12 carbon atoms.

Specifically, R is preferably a hydrogen atom; for example, a methyl group, an ethyl group, an n-propyl group, is
o-propyl group, n-butyl group, iso-butyl group, s
ec-butyl group, t-butyl group, n-pentyl group, 2-
It may be substituted with an aliphatic or aromatic hydrocarbon group having 1 to 6 carbon atoms such as a methyl-2-butyl group, an n-hexyl group, a cyclohexyl group, a 1-adamantyl group, a 2-adamantyl group, and a benzyl group. Examples thereof include a chain or cyclic alkyl group having 1 to 10 carbon atoms. Alternatively, R is preferably 1 to 3 heteroatoms such as phenyl, tolyl, ethylphenyl, propylphenyl, dimethylphenyl, diethylphenyl, dipropylphenyl, and methoxyphenyl. (Oxygen atom,
Examples thereof include a phenyl group which may be substituted with an aliphatic hydrocarbon group having 1 to 6 carbon atoms which may contain a sulfur atom and / or a nitrogen atom).

Suitable examples of M include sodium, potassium, rubidium, cesium, francium, magnesium, calcium, strontium, barium, and radium. Of these,
Since isotactic polystyrene can be produced with a smaller amount, M is more preferably potassium.

That is, the compounds represented by the above formula (I) of the present invention are more specifically potassium hydroxide, potassium methoxide, potassium ethoxide, potassium-n-
Propoxide, potassium-iso-propoxide, potassium-n-butoxide, potassium-sec-butoxide, potassium-iso-butoxide, potassium-t-butoxide, potassium-n-pentoxide, potassium-2
-Methyl-2-butoxide, potassium-n-hexoxide, potassium-cyclohexoxide, potassium-1-adamantoxide, potassium-2-adamantoxide, potassium-phenylmethoxide, potassium phenoxide and the like are preferable, and potassium-t- Butoxide, potassium-2
-Methyl-2-butoxide is more preferred. These may be used alone or in combination of two or more.

The amount of the compound represented by the above formula (I) depends on the type of the compound and the type of the anionic polymerization initiator, but is usually 0.1 mol to 10 mol per 1 mol of the initiator.
0 mol, preferably 0.2 mol to 50 mol, more preferably 0.3 mol to 10 mol. If the amount is too small, no steric control effect can be obtained, and if it is too large, the effect does not increase, but the compound is wasted, which is not preferable. In the present invention, the degree of isotacticity can be controlled by the molar ratio between the anionic polymerization initiator and the compound.

In the present invention, styrene and, if necessary, a conjugated diene are polymerized in the presence of the anionic polymerization initiator and the compound represented by the formula (I). As the conjugated diene, 1,3-cyclopentadiene, 1,3-cyclohexadiene, 1,3-cycloheptadiene, 1,3
Cyclic conjugated dienes such as cyclooctadiene and derivatives thereof; 1,3-butadiene, isoprene, 1,3-
Chain conjugated dienes such as pentadiene, 1,3-hexadiene and 2,3-dimethyl-1,3-butadiene can be mentioned. Of these, butadiene and isoprene are preferred, and isoprene is more preferred, in terms of high reactivity and easy availability. These may be used alone or in combination of two or more. By adding a conjugated diene, an effect of improving toughness can be expected. The addition amount of the conjugated diene is not particularly limited, but is preferably 1% by weight or more and 30% by weight or less, more preferably 2% by weight or more and 25% by weight or less, still more preferably 3% by weight or more and 20% by weight or less based on styrene. It is. If the conjugated diene is more than 30% by weight, the effect of improving toughness is large,
It is not preferable because the heat distortion temperature is lowered. On the other hand, if the conjugated diene is less than 1% by weight, the effect of improving the toughness by introducing the conjugated diene is not obtained, which is not preferable. In the present invention, both styrene and conjugated dienes have high reactivity and can be converted to a polymer almost quantitatively.

As a method of polymerizing styrene and a conjugated diene, a method of sequentially polymerizing styrene and isoprene to produce a block copolymer, a method of performing polymerization in the presence of both styrene and a conjugated diene, Although a method of producing a coalesced or random copolymer can be mentioned, it is preferable to use a block copolymer in order to introduce a conjugated diene at a minimum and to exert the effect of improving toughness to the maximum.

As a component other than styrene and conjugated diene, another monomer capable of being anionically polymerized may be introduced in an amount of about 5% by weight or less of the whole polymer. Other monomers capable of anionic polymerization include o-methylstyrene, m-methylstyrene, p-methylstyrene and α-methylstyrene.
Styrene-based monomers such as methylstyrene, vinylnaphthalene and α-methyl-vinylnaphthalene can be exemplified. These may be used alone or in combination of two or more.

In the polymerization in the present invention, a solution polymerization technique can be suitably applied. The solvent used in the solution polymerization is not particularly limited as long as it dissolves the polymer and does not deactivate the active terminal at the time of polymerization, but preferred examples include butane, n-pentane, n-hexane, Aliphatic hydrocarbons having 4 to 12 carbon atoms such as n-heptane; and 4-1 carbon atoms such as cyclobutane, cyclopentane, methylcyclopentane, cyclohexane, methylcyclohexane, cycloheptane, cyclooctane and decalin
2, alicyclic hydrocarbons; benzene, toluene, xylene,
Mesitylene, ethylbenzene, diethylbenzene, cumene, tetralin, naphthalene and other aromatic hydrocarbons having 6 to 12 carbon atoms, diethyl ether, tetrahydrofuran,
Examples thereof include ethers having 4 to 12 carbon atoms such as methyl-t-butyl ether. Of these, aliphatic hydrocarbons, alicyclic hydrocarbons, and ethers are preferred, and cyclohexane, methylcyclohexane, and methyl-t-butyl ether are particularly preferred.

The reaction conditions in the polymerization are not particularly limited because they differ depending on the polymerization method and the like, but preferable conditions are a temperature of -50 ° C to 150 ° C, preferably -30 ° C to 100 ° C, more preferably 0 ° C to 70 ° C,
The reaction time is 5 minutes to 20 hours, preferably 10 minutes to 15 hours, more preferably 20 minutes to 10 hours. In addition, since the active end may be very sensitive to water, oxygen, etc. during the polymerization reaction, the reaction is carried out under an inert atmosphere such as nitrogen or argon, and in an environment where reagents, solvents, and inert gases are sufficiently dehydrated. Is preferred.

The isotactic polystyrene-based polymer thus obtained is subjected to isotactic dyad.
1% to 80%. Isotactic dyads are described, for example, in Inoue et al., Macromol. Chem. , 156
Volume, page 256 (1972), and can be derived by analyzing a nuclear magnetic resonance spectrum.

The terminal of the isotactic polystyrene polymer in the present invention is anionized immediately after polymerization. Therefore, by adding a coupling agent that forms a bond with a terminal anion, a copolymer in which the copolymer is bonded in a chain or star-shaped branch can be synthesized. Examples of the coupling agent used herein include halogenated silanes such as dimethyldichlorosilane, methyltrichlorosilane, tetrachlorosilane, and tetrabromosilane; dimethyldimethoxysilane, methyltrimethoxysilane, tetramethoxysilane, bis (trimethoxysilyl) methane, Bis (trimethoxysilyl) ethane,
Alkoxysilanes such as dimethyldiethoxysilane, methyltriethoxysilane, tetraethoxysilane, bis (triethoxysilyl) methane, bis (triethoxysilyl) ethane and tetraphenoxysilane, allyloxysilanes; α, α'-dichloro Halides such as xylene, α, α'-dibromoxylene, tetrakis (chloromethyl) benzene and tetrakis (bromolomethyl) benzene; esters such as dimethyl oxalate, dimethyl succinate, dimethyl glutarate, dimethyl phthalate and dimethyl terephthalate And the like.

(Styrene-based polymer hydride) In the present invention, the above-mentioned isotactic polystyrene-based polymer is hydrogenated in the presence of a hydrogenation catalyst to produce a hydrogenated isotactic polystyrene-based polymer. .

The hydrogenation catalyst is not particularly limited as long as it can hydrogenate the aromatic ring and the carbon-carbon double bond contained in the copolymer. Specific examples of preferred hydrogenation catalysts include nickel, palladium, platinum and platinum. Examples include solid catalysts in which a noble metal such as cobalt, ruthenium, and rhodium or an oxide, salt, or complex thereof is supported on a porous carrier such as carbon, alumina, silica, silica alumina, and diatomaceous earth.
Among them, those in which nickel, palladium, platinum, and ruthenium are supported on alumina, silica, silica alumina, and diatomaceous earth exhibit high reactivity and are preferably used. Specifically, nickel / silica, nickel / alumina, nickel / silica alumina, nickel / diatomaceous earth, palladium / silica, palladium / alumina, palladium / silica alumina, palladium / diatomaceous earth, platinum / silica, platinum / alumina, platinum / silica alumina , Platinum / diatomaceous earth, ruthenium / silica, ruthenium / alumina, ruthenium / silica-alumina, ruthenium / diatomaceous earth, etc., among which nickel / silica, nickel /
Alumina, nickel / silica alumina, palladium / silica, palladium / alumina, palladium / silica alumina are preferred. Such a hydrogenation catalyst is preferably used in the range of 0.5% by weight to 40% by weight based on the copolymer, depending on the catalytic activity.

The hydrogenation is achieved by hydrogenating the aromatic ring and the carbon-carbon double bond contained in the isotactic polystyrene-based polymer. The hydrogenation reaction may be performed after once isolating the polymer after the polymerization reaction, but it is also possible to use the reaction mixture after the polymerization as it is or to add a necessary solvent. Such a solvent is preferably selected in consideration of the hydrogenation catalytic ability, the presence or absence of side reactions such as molecular chain scission, the solubility of the polymer before and after the hydrogenation reaction, and the like. Specifically, butane, n-pentane, C4-12 aliphatic hydrocarbons such as n-hexane and n-heptane; cyclobutane, cyclopentane, methylcyclopentane,
C4-12 alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, cycloheptane, cyclooctane and decalin; and C4-12 ethers such as diethyl ether, tetrahydrofuran and methyl-t-butyl ether. Of these, cyclohexane, methylcyclohexane, and methyl-t-butyl ether are particularly preferred, though depending on the type of catalyst. In addition, polar solvents such as esters and alcohols are added to the above-mentioned solvents within a range not hindering the solubility of the polymer, for the purpose of increasing the activity of the reaction, or suppressing the molecular weight reduction due to molecular chain breakage due to hydrogenolysis. You may.

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

The hydrogenation reaction conditions depend on the catalyst used, but are usually 3 to 25 MPa in hydrogen pressure and 70 to 220 in reaction temperature.
It is performed within the range of ° C. If the reaction temperature is too low, the reaction hardly proceeds, and if the reaction temperature is too high, the molecular weight is likely to be reduced by hydrogenolysis, which is not preferable. In order to prevent a decrease in molecular weight due to molecular chain breakage and promote the reaction smoothly, hydrogenation is carried out at an appropriate temperature and hydrogen pressure, which is appropriately determined according to the type and concentration of the catalyst used, the concentration of the polymer solution, the molecular weight, and the like. It is preferred to carry out the reaction.

When the isotactic polystyrene polymer of the present invention is used as an optical material, the hydrogenation rate is preferably 90 to 100%, more preferably 95 to 100%, and still more preferably 98 to 100%. 100%
It is. If the hydrogenation rate is too low, the transparency and heat distortion temperature of the copolymer decrease, which is not preferable. Here, the hydrogenation rate refers to the total hydrogenation rate of the aromatic ring and the double bond in the copolymer, replacing the aromatic ring with the number of moles corresponding to the double bond. . For example, unhydrogenated styrene sites are calculated as 3 moles of double bonds. Usually, the double bond derived from the conjugated diene is much more easily hydrogenated than the aromatic ring, and is almost completely hydrogenated in the present invention. On the other hand, when the aromatic ring is not hydrogenated, most of the ring remains the aromatic ring, but there are cases where the hydrogenation is partially hydrogenated to form a double bond. .

After the completion of the hydrogenation reaction, the catalyst can be removed by a known post-treatment method such as centrifugation or filtration. In the present invention used for engineering material applications, it is necessary to reduce the residual catalyst metal component in the resin as much as possible, and the amount of such residual metal catalyst is preferably 10 ppm or less, more preferably 1 ppm or less, and even more preferably 5 ppm or less.
00 ppb or less. In particular, in the present invention, among the residual metal catalysts, it is preferable to use a polymer having a transition metal content of 10 ppm or less, more preferably 5 ppm or less. From the polymer solution from which the hydrogenation catalyst has been removed, the desired isotactic polystyrene-based polymer can be obtained by a method such as evaporation of the solvent, stripping, or reprecipitation.

In the hydrogenated isotactic polystyrene polymer thus obtained, the isotactic dyad of the hydrogenated styrene polymerized portion is preferably 50.1% to 80%. 8 isotactic diads
If it is more than 0%, the crystallinity is increased and the transparency is reduced, so that it cannot be suitably used for engineering materials such as the present invention, and is not preferred. If it is less than 50.1%, the toughness is undesirably reduced. More preferably, the isotactic dyad is 60% to 80% or less, more preferably 70% to 80%, even more preferably 75% to 80%. Isotactic dyads are described in Ros et al., Int. J. Polym. Anal. C
haract. 4, p. 39 (1997), it can be estimated by measuring the nuclear magnetic resonance spectrum of the polymer. Further, since the three-dimensional structures of the styrene polymerized portion and the hydrogenated styrene polymerized portion do not change before and after hydrogenation, the values estimated for the polymer before hydrogenation can be applied as they are.

The number average molecular weight of the hydride of the isotactic polystyrene polymer in the present invention is preferably a molecular weight in terms of polystyrene obtained by gel permeation chromatography (GPC) of preferably 30,0.
00 to 200,000, more preferably 50,000 to
180,000, more preferably 60,000 to 16
It is in the range of 0000. If the number average molecular weight is larger than that, the hydrogenation reaction becomes difficult, and the melt viscosity of the hydrogenated copolymer becomes too high, making melt molding difficult, which is not preferable. If it is less than this, the hydrogenation reaction becomes easy and the melt viscosity of the hydrogenated copolymer decreases, but the toughness decreases, which is not preferable.

The reduced viscosity measured in a dilute solution is also an important measure for grasping the molecular weight. In the present invention, the reduced viscosity is preferably from 0.1 dL / g to 5 dL / g, and more preferably from 0 to 5 dL / g, expressed in terms of reduced viscosity ηsp / c measured at 30 ° C. in a toluene solution having a concentration of 0.5 g / dL. .2 dL / g to 2 dL / g.

The weight ratio of units derived from hydrogenated styrene / units derived from hydrogenated conjugated diene in the hydrogenated isotactic polystyrene polymer of the present invention is 70/30.
The range of 範 囲 100/0 is preferred. The weight ratio is 70 /
If it is smaller than 30, the toughness is improved, but the heat deformation temperature is remarkably lowered, so that it cannot be suitably used as an optical material such as an optical disk, which is not preferable. A more preferable range of the weight ratio is 80/20 to 100/0, and further preferably 85/15 to 100/0. Such a weight ratio can be obtained by measuring a proton nuclear magnetic resonance spectrum of the hydrogenated copolymer, estimating a molar ratio of a unit derived from hydrogenated styrene and a unit derived from a hydrogenated conjugated diene, and converting to a weight ratio. it can.

The hydride of the isotactic polystyrene polymer obtained in the present invention may be used as a blend of the copolymer having a different molecular weight or a composition with another polymer according to the purpose. The mixing ratio is not particularly limited and may be appropriately determined in consideration of the physical properties of the composition. Usually, the weight ratio of the hydride of the isotactic polystyrene-based polymer / the polymer to be mixed is 1/99 to 99. / 1 is more preferable, 20/80 to 80/20 is more preferable, and 40/60 to 60/40 is more preferable. Examples of other polymers include a hydrogenated styrene-based polymer described in JP-A-63-4391 and a hydrogenated styrene-based hydrocarbon-conjugated diene-based hydrocarbon copolymer described in JP-A-10-116442. Coalescence and the like.

The hydride of the isotactic polystyrene-based polymer of the present invention contains Irganox 1010 and 1076 (manufactured by Ciba-Geigy) in order to improve thermochemical stability during melt molding or to prevent autoxidation. Hindered phenol stabilizer such as Irgafos 16
It is preferable to add a phosphine stabilizer such as No. 8 (manufactured by Ciba Geigy) or an acrylic hindered phenol stabilizer such as Sumilizer GM or Sumilizer GS (manufactured by Sumitomo Chemical). Also, if necessary, long-chain aliphatic alcohols, release agents such as long-chain aliphatic esters, other lubricants,
Additives such as a plasticizer, an ultraviolet absorber, and an antistatic agent can be added.

The hydride of the isotactic polystyrene polymer of the present invention can be molded by a known method such as injection molding, injection compression molding, extrusion molding, and solution casting. In particular, it can be suitably used for manufacturing optical disk substrates or optical lenses by injection molding or injection compression molding. In such molding, the resin temperature is 250 to 360.
° C, preferably 270-350 ° C, more preferably 2 ° C
The range of 80 to 340 ° C is used, and the mold temperature is 60 to 1
A range of 40 ° C, preferably 70 to 130 ° C, more preferably 80 to 125 ° C is used.

[0047]

According to the present invention, a method for producing an isotactic polystyrene-based polymer and a hydride thereof is provided. By using the method of the present invention, an isotactic polystyrene-based polymer can be synthesized even at a temperature of about room temperature, and as a result, the polymerization rate can be increased. The value of the isotactic dyad can be controlled by changing the ratio of the compound represented by the formula (I) to the anionic polymerization initiator. Isotactic polystyrene-based polymer hydride has high transparency, and is excellent in toughness, heat resistance, and moldability, and thus can be suitably used as an optical material such as an optical disk substrate.

[0048]

The present invention will be described below in detail with reference to examples. However, the present invention is not limited to these examples.

(Reagents and Solvents) Styrene and isoprene were purified by distillation from calcium hydride and used after being sufficiently dried. Cyclohexane and methyl-t-butyl ether were purchased in a dehydrated grade, and used after further contacting with 4A molecular sieve or basic alumina and sufficiently drying.

An n-butyllithium-hexane solution, potassium-t-butoxide, and tetramethylethylenediamine were purchased from Kanto Chemical Co., and used as they were.

The di (n-butyl) magnesium-heptane solution was purchased from Aldrich and used as is.

Potassium-2-methyl-2-butoxide was purchased from Azmax Co., Ltd. as a cyclohexane solution and used as it was.

(Measurement of physical properties) Number average molecular weight (Mn), weight average molecular weight (Mw): gel permeation chromatography (GPC, Syodex S, manufactured by Showa Denko KK)
ystem-11) using tetrahydrofuran as a solvent, and was determined from the molecular weight in terms of polystyrene at 40 ° C.

Molecular weight distribution: The ratio Mw / Mn of the number average molecular weight (Mn) to the weight average molecular weight (Mw) was calculated.

Isotactic Dyad: JEOL
Using a JNM-alpha600 type nuclear magnetic resonance absorption apparatus, Inoue et al., Macromol. Chem. , 156
Winding, in accordance with 256 pages (1972), the before hydrogenation of the polymer dissolved in orthodichlorobenzene -d _4, at 140 ° C. ¹³
It was calculated by measuring C-NMR.

Hydrogenation rate: JEOL JNR-EX270
The hydrogenation rate was determined by ¹ H-NMR measurement using a nuclear magnetic resonance absorption apparatus.

Weight ratio of units derived from hydrogenated styrene to units derived from hydrogenated isoprene: JEOLJNM-alpha
¹ H-NMR measurement of the hydrogenated copolymer in deuterated chloroform at 55 ° C. was performed using a 600-type nuclear magnetic resonance absorption apparatus, and the integral ratio of hydrogenated styrene-derived signals appearing at 1.6 to 2.0 ppm was estimated. Was calculated.

Molding of molded pieces: Molded pieces were molded by an injection molding machine (M50B manufactured by Meiki Seisakusho Co., Ltd.).

Total light transmittance, haze: JIS K71
The measurement was performed using a 2 mm-thick disk-shaped molded piece in accordance with Example No. 05.

Glass transition point: TA Instrument
s Model 2920 DSC was used and the heating rate was 20 ° C /
Measured in minutes.

Thermal deformation temperature: Measured according to JIS K 7207 under a load of 181.3 N / cm ² .

Izod impact strength: JIS K 7110
UFIMPACT TES manufactured by Kamishima Seisakusho
An impact test was performed without notch using TER and measured.

[Comparative Example 1] 320 g of styrene and 1600 g of cyclohexane were charged into a metal autoclave which was sufficiently dried and purged with nitrogen. After heating the solution to 40 ° C., a 1.6 M n-butyllithium-hexane solution 1.
5 mL was added, and the mixture was reacted for 1 hour. After completion of the reaction, 0.7 g of isopropanol was added to obtain polystyrene. The isotactic diad was 45%. The number average molecular weight was 180,000 and the molecular weight distribution was 1.25.

Example 1 In a metal autoclave sufficiently dried and purged with nitrogen, 320 g of styrene, 1600 g of cyclohexane and 255 mg of potassium tert-butoxide were placed.
Was charged. After heating the solution to 40 ° C., 1.5 mL of 1.6 M n-butyllithium-hexane solution was added,
The reaction was performed for 1 hour. After completion of the reaction, isopropanol was added.
7 g was added to obtain isotactic polystyrene. The isotactic diad was 76%. The number average molecular weight was 235,000, and the molecular weight distribution was 1.42. Therefore, it was found that potassium-t-butoxide had no effect of reducing the molecular weight distribution and was effective in controlling the stereoregularity.

[Comparative Example 2] 270 mg of tetramethylethylenediamine was used instead of potassium-t-butoxide.
The same operation as in Example 1 was performed except for (2.3 mmol) to obtain polystyrene. The isotactic diad was 45%. The number average molecular weight is 170,00
0, molecular weight distribution was 1.02. Therefore, it was found that tetramethylethylenediamine had an effect of reducing the molecular weight distribution, but had no effect of controlling the stereoregularity.

Example 2 Isotactic polystyrene was obtained in the same manner as in Example 1 except that the amount of potassium-t-butoxide charged was changed to 96 mg. The isotactic diad was 55%. The number average molecular weight was 230,000 and the molecular weight distribution was 1.45.

Example 3 Isotactic polystyrene was prepared in the same manner as in Example 1 except that 2.4 mL of a 1.0 M di (n-butyl) magnesium-heptane solution was used instead of n-butyllithium. I got The isotactic diad was 72%. The number average molecular weight was 150,000, and the molecular weight distribution was 1.02.

Example 4 Instead of potassium t-butoxide, 200 m of potassium-2-methyl-2-butoxide was used.
An isotactic polystyrene was obtained in the same manner as in Example 1 except that g was used. The isotactic diad was 78%. The number average molecular weight is 220,00
0, molecular weight distribution was 1.48.

Example 5 190 g of styrene, 745 g of cyclohexane, and 360 mg of potassium tert-butoxide were charged into a metal autoclave which had been sufficiently dried and purged with nitrogen. Further, 2.2 mL of a 1.6 M n-butyllithium-hexane solution was added, and the mixture was heated to 50 ° C. and reacted for 2 hours. Next, 50 g of isoprene was added as a cyclohexane solution, and the mixture was further reacted for 2 hours. Subsequently, 220 g of styrene and 890 g of cyclohexane were added and reacted for 2 hours. After the completion of the reaction, 0.7 g of isopropanol was added to obtain an isotactic styrene-isoprene-styrene block copolymer. The isotactic dyad of the styrene polymerization portion was 77%. Also,
The number average molecular weight is 110,000 and the molecular weight distribution is 1.67.
was. The weight ratio of the unit derived from styrene / the unit derived from isoprene was 93/7.

Example 6 1300 g of cyclohexane and 70% of methyl tert-butyl ether were added to the solution obtained in Example 1.
0g nickel / silica alumina 50g, hydrogen pressure 1
The hydrogenation reaction was performed at 0 MPa and a temperature of 180 ° C. for 5 hours.
After removing the solution from the autoclave, the hydrogenation catalyst was removed by filtration. 2700 ppm of Sumilizer GS as a stabilizer was added to the resulting solution, and the solvent was distilled off to obtain a hydrogenated styrene-isoprene copolymer. The hydrogenation rate was over 99%. Also, GP
The number average molecular weight determined from C was 140,000 and the molecular weight distribution was 1.43. A molded piece was prepared using the hydrogenated copolymer, and various physical properties were measured. Total light transmittance is 9
It was as high as 2.0%. The glass transition point is 140 ° C,
Thermal deformation temperature is 111 ° C, Izod impact strength is 7.3J /
m ² was a sufficient value.

Example 7 1300 g of cyclohexane and 70% of methyl-t-butyl ether were added to the solution obtained in Example 5.
0g nickel / silica alumina 50g, hydrogen pressure 1
The hydrogenation reaction was performed at 0 MPa and a temperature of 180 ° C. for 5 hours.
After removing the solution from the autoclave, the hydrogenation catalyst was removed by filtration. 2700 ppm of Sumilizer GS as a stabilizer was added to the resulting solution, and the solvent was distilled off to obtain a hydrogenated styrene-isoprene copolymer. The hydrogenation ratio was 99% or more, and the weight ratio of units derived from hydrogenated styrene / units derived from hydrogenated isoprene was 93/7. The number average molecular weight determined by GPC was 90,000, and the molecular weight distribution was 1.70. A molded piece was prepared using the hydrogenated copolymer, and various physical properties were measured. The total light transmittance was as high as 91.6%. Also,
Glass transition point is 135 ° C, heat deformation temperature is 101 ° C, Iz
The od impact strength showed a sufficient value of 8.5 J / m ² .

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J015 DA02 DA03 DA33 4J100 AA20P AB02P CA01 CA11 CA31 FA03 FA08 HA05 HB02 HB17 HB36 HB61 HC13 JA32 JA36 5D029 KA13

Claims (7)

[Claims] 1. An anionic polymerization initiator and a compound represented by the following formula (I): (In the formula, n is 1 or 2, and R is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 12 carbon atoms, or 6 to 6 carbon atoms.
Styrene and, if necessary, conjugated diene in the presence of a compound represented by the formula (12), wherein M is an alkali metal or alkaline earth metal excluding lithium and beryllium: A method for producing an isotactic polystyrene polymer. 2. The method according to claim 1, wherein M is potassium. 3. A method for producing a hydrogenated isotactic polystyrene polymer, comprising hydrogenating the isotactic polystyrene polymer according to claim 1 or 2 in the presence of a hydrogenation catalyst. 4. An isotactic polystyrene-based polymer obtained by the production method according to claim 1 or 2, wherein the styrene polymerized portion has an isotactic dyad of 50.1% to 80%. 5. A hydrogenated isotactic polystyrene polymer having an isotactic dyad of 50.1% to 80% in a hydrogenated styrene polymerized portion obtained by the production method according to claim 3. 6. An optical material mainly comprising the hydride of the isotactic polystyrene-based polymer according to claim 5. 7. An optical disk substrate mainly comprising the hydride of the isotactic polystyrene-based polymer according to claim 5.