JP2000119337A - Transparent aromatic vinyl compound-ethylene copolymer and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a transparent styrene-ethylene copolymer having high transparency, stereoregularity and a styrene chain structure of head-tail, and to provide its producing method. SOLUTION: This transparent aromatic vinyl compound-ethylene copolymer satisfies the following conditions. (1) A content of the aromatic vinyl compound is 1-30 mol %. (2) A stereoregularity of phenyl group of an alternate structure of an aromatic vinyl compound and ethylene contained in the copolymer measured as isotactic diad fraction (m) is larger than 0.75. (3) In a molded material having 1.0 mm thickness, haze is lower than 40%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a transparent aromatic vinyl compound-ethylene copolymer having high transparency and a method for producing the same.

[0002]

2. Description of the Related Art There are known several styrene-ethylene copolymers obtained by using a so-called homogeneous Ziegler-Natta catalyst system comprising a transition metal catalyst component and an organoaluminum compound, and a method for producing the same. JP-A-3-16308
No. 8, JP-A-7-53618 discloses a styrene-ethylene copolymer having no normal styrene chain, which is obtained by using a complex having a so-called constrained geometric structure.
So-called pseudo-random copolymers are described. Note that a normal St chain refers to a chain of head-tail bonds. In addition, styrene may be described as St below. The phenyl group having an alternating styrene-ethylene structure present in the pseudorandom copolymer has no stereoregularity. Also, due to the absence of normal styrene chains, the styrene content cannot exceed 50 mol%.

JP-A-6-49132 and Pol
ymer Preprints, Japan, 42 , 2
292 (1993) describes a method for producing a similar styrene-ethylene copolymer having no normal St chain, that is, a so-called pseudo-random copolymer using a catalyst composed of a bridged metallocene Zr complex and a cocatalyst. I have. Poly
mer Preprints, Japan, 42 , 22
According to N.92 (1993), the phenyl group having an alternating styrene-ethylene structure present in the pseudorandom copolymer has no substantial stereoregularity. Also, as in the case of complexes having a constrained geometry, the absence of normal styrene chains prevents the styrene content from exceeding 50 mol%. The activity is also insufficient for practical use. More recently, certain bridged bisindenyl Zr complexes, ie, rac [ethylenebis (indenyl) z
A styrene-ethylene copolymer close to an alternating copolymer having stereoregularity under cryogenic (-25 ° C.) conditions has been reported using irconium dichloride (racemic [ethylenebis (indenyl) zirconium dichloride]). . (Macromol. Che
m. , Rapid Commun. , 17 , 745 (1
996). However, it is clear from the published 13 C-NMR spectrum and the description of the article that there is no head-tail styrene linkage in this copolymer. Further, when copolymerization is carried out at a polymerization temperature of room temperature or higher using this complex, only a copolymer having low styrene content and low molecular weight can be obtained. Further, the styrene-ethylene copolymer obtained using each of the above catalyst systems has poor transparency, particularly in a relatively low styrene content range. This is thought to be due to the non-uniformity of the copolymer, that is, the presence of many components having a styrene content significantly lower or higher than the average.

Japanese Patent Application Laid-Open No. 9-309925 discloses that a styrene content of 1 to 55 mol%, obtained by using a polymerization catalyst comprising a zirconocene complex having an indenyl group cross-linked with an isopropylidene group and a cocatalyst, is used. Ethylene alternating structure has isotactic stereoregularity,
A novel ethylene-styrene copolymer having an alternating degree of copolymer (λ value in the present specification) of 70 or less is described.
However, this catalyst system has a low ability to form a head-tail styrene chain, and it is difficult to observe the head-tail styrene chain structure in a styrene content region of substantially 30 mol% or less. It is described that this copolymer can have a head-tail styrene chain structure in a styrene content range of 20 mol% or more.

[0005] WO 98/09999 discloses a specific zirconocene complex {rac-dimethylsilylen.
ebis (2-methyl, 4-phenyl-1-
indenyl) zirconium dichlori
Styrene-ethylene copolymers obtained using de｝ are described. The copolymer has a wide molecular weight distribution and a large composition distribution. Copolymers with a styrene content of the order of 10 mol% also contain a polyethylene component and are therefore opaque copolymers.

[0006]

SUMMARY OF THE INVENTION The present invention overcomes these disadvantages of the prior art and has high transparency, stereoregularity, and a transparent styrene-ethylene copolymer having a head-to-tail styrene chain structure. An object of the present invention is to provide a combination and a method for producing the same.

[0007]

The present invention is a transparent aromatic vinyl compound-ethylene copolymer having high transparency and satisfying the following conditions. (1) Aromatic vinyl compound content 1 mol% or more and 30 mol%
The content is particularly preferably from 5 mol% to 20 mol%, more preferably from 5 mol% to 15 mol%. (2) The stereoregularity of the phenyl group in the alternating structure of the aromatic vinyl compound represented by the following general formula (1) and ethylene contained in the copolymer structure is 0.75 in isotactic dyad fraction m. Greater, preferably greater than 0.85, particularly preferably greater than 0.95.

[0008]

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Wherein Ph is an aromatic group such as a phenyl group;
x represents the number of repeating units and represents an integer of 2 or more. (3) Haze is 40% in a molded product having a thickness of 1.0 mm.
Or less, particularly preferably 25% or less.

Further, the copolymer of the present invention is an aromatic vinyl compound-ethylene copolymer obtained by a homopolymerization of styrene using a catalyst capable of producing polystyrene having isotactic stereoregularity. including.
The present invention includes an aromatic vinyl compound-ethylene copolymer having a molecular weight distribution of 3.0 or less, obtained by using this type of catalyst. Further, the copolymer of the present invention may contain two or three copolymers.
An aromatic vinyl compound-ethylene copolymer having a head-tail chain structure of at least two aromatic vinyl compound units is included. Its structure is determined by nuclear magnetic resonance (NMR). The copolymer of the present invention has main peaks at the following positions in 13C-NMR based on TMS. Peaks derived from main chain methylene and main chain methine carbon were around 24 to 25 ppm, around 27 ppn, 30
around ppm, 34-37 ppm, 40-41 ppm
Near and around 42 to 46 ppm, and peaks derived from five carbons of the phenyl group which are not bonded to the polymer main chain were around 126 ppm and 128 ppm,
The peak derived from one carbon atom bonded to the polymer main chain among the phenyl groups is shown at around 146 ppm.

The copolymer of the present invention has an aromatic vinyl compound content of 1 mol% to 30 mol%, preferably 5 mol% to 20 mol%, more preferably 5 mol% to 15 mol%. The stereoregularity of the phenyl group of the alternating structure of the aromatic vinyl compound represented by the following general formula (1) and ethylene contained in the copolymer structure is greater than 0.75 in isotactic dyad fraction m. , Preferably greater than 0.85, particularly preferably greater than 0.95.

[0012]

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(Wherein Ph is an aromatic group such as a phenyl group,
x represents the number of repeating units and represents an integer of 2 or more. When the aromatic vinyl compound is styrene, the isotactic dyad fraction m of the alternating copolymer structure of ethylene and styrene has a peak area Ar derived from an r structure of a methylene carbon peak appearing at around 25 ppm, and an m structure From the peak area Am derived from the following formula (ii). m = Am / (Ar + Am) Formula (ii) The appearance position of the peak may be slightly shifted depending on the measurement conditions and the solvent. For example, using deuterated chloroform as a solvent,
Based on TMS, the peak derived from the r structure is
The peak derived from the m-structure appears around 25.4 to 25.5 ppm, and around 25.2 to 25.3 ppm. Also,
When heavy tetrachloroethane is used as a solvent and the center peak (73.89 ppm) of the triplet of heavy tetrachloroethane is used as a reference, the peak derived from the r structure is 25.3 to 2
Around 5.4 ppm, the peak derived from the m-structure was 25.
Appears around 1-25.2 ppm. Note that the m structure represents a meso diad structure, and the r structure represents a racemic diad structure. In the styrene-ethylene random copolymer of the present invention, the peak attributed to the r structure in the alternating copolymer structure of ethylene and styrene is not substantially observed.

[0014] Transparency is obtained by molding, preferably a film,
It is represented by the haze value of the sheet and is 40% or less, preferably 2% or less.
5% or less. Further, the aromatic vinyl compound-ethylene copolymer of the present invention can have a head-tail chain structure of two or more aromatic vinyl compounds represented by the following structure.

[0015]

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Here, n is an arbitrary integer of 2 or more. Ph
Represents an aromatic group such as a phenyl group.

The styrene-ethylene copolymer which is an example of the aromatic vinyl compound-ethylene copolymer of the present invention will be described below. However, the present invention is not limited to a styrene-ethylene copolymer. The present invention
According to 13C-NMR measurement based on TMS, 40 to
A styrene-ethylene copolymer characterized by having a styrene chain structure attributed to a peak observed at 45 ppm, preferably 42.3 to 43.1.
ppm, 43.7-44.5 ppm, 40.5-41.
0 ppm, a styrene-ethylene copolymer having a chain structure of styrene units attributed to peaks observed at 43.0 to 43.6 ppm, more preferably 42.3 to 43.1 ppm, 4
It is a transparent styrene-ethylene copolymer having a chain structure of styrene units assigned by peaks observed at 3.7 to 44.5 ppm.

Further, in the present invention, the amount of the aromatic vinyl compound unit derived from the head-tail chain structure of the aromatic vinyl compound unit is preferably 0.1% of the total amount of the aromatic vinyl compound unit contained in the copolymer. % Or more, particularly preferably 1% or more, most preferably 5% or more. The aromatic vinyl compound-olefin random copolymer is characterized in that the aromatic vinyl compound unit contained in the copolymer is The ratio χ of the amount of aromatic vinyl compound units derived from the head-tail chain structure to the total amount of aromatic vinyl compound units can be determined by the following formula. χ = χa / χb × 100 χa; Sum of peak areas derived from main chain methine carbon in a head-tail chain structure of two or more aromatic vinyl compound units. For example, 1 based on TMS
In 3C-NMR measurement, 40.5 to 41.0 ppm
Peak (n) observed at 42.3-44.5 ppm
The sum of the peaks (j) observed in the above. χb: The sum of the peak areas derived from the main chain methine carbon of the whole aromatic vinyl compound unit contained in the copolymer.

Further, the copolymer of the present invention is preferably a copolymer represented by the following formula (i) wherein the copolymer has an alternating structure index λ of less than 70 and greater than 0.1, and λ is preferably More preferably, the copolymer is smaller than 30 and larger than 0.1. λ = A3 / A2 × 100 Formula (i) Here, A3 is three kinds of peaks a and b derived from a styrene-ethylene alternating structure represented by the following general formula (1 ′) and obtained by 13 C-NMR measurement. , C is the sum of the areas. A2 is 13C-NM based on TMS.
It is the total sum of the areas of peaks derived from main chain methylene and main chain methine carbon observed in the range of 0 to 50 ppm by R.

[0020]

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(In the formula, Ph represents a phenyl group, x represents the number of repeating units, and represents an integer of 2 or more.)

[0022]

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(Wherein Ph is an aromatic group such as a phenyl group,
x represents the number of repeating units and represents an integer of 2 or more. )

Further, in the styrene-ethylene copolymer of the present invention, the stereoregularity of the phenyl group in the chain structure of the styrene unit is preferably isotactic. Isotacticity of the stereoregularity of the phenyl group in the chain structure of the styrene unit means that the isotactic dyad fraction ms (or the meso dyad fraction) is 0.5.
It refers to a structure showing a larger, preferably 0.7 or more, more preferably 0.8 or more. The stereoregularity of the chain structure of the styrene unit is determined by the peak position of methylene carbon and the peak area intensity ratio around 43 to 44 ppm observed by 13 C-NMR, and / or the peak of the main chain proton observed by 1 H-NMR. It is determined by the position and the peak area intensity ratio. In addition, the present copolymer is expressed as a styrene-ethylene copolymer having a head-tail styrene chain structure obtained by using a metallocene catalyst capable of producing isotactic polystyrene by homopolymerization of styrene. You can also.

Further, the copolymer has a weight average molecular weight in terms of polystyrene of 10,000 or more, preferably 50,000 or more, particularly preferably 80,000 or more, and a molecular weight distribution (Mw / M
n) is a styrene-ethylene copolymer having 6 or less, preferably 4 or less, and more preferably 3 or less. In consideration of the moldability of the copolymer, the weight average molecular weight is preferably 1,000,000 or less, more preferably 500,000 or less. Here, the weight average molecular weight refers to a molecular weight in terms of polystyrene obtained by using GPC with standard polystyrene.
The same applies to the following description.

On the other hand, in the case of a conventionally known so-called pseudo-random copolymer, a head-tail chain structure of styrene cannot be found even at a maximum styrene content of around 50 mol%. Further, even if homopolymerization of styrene is attempted using a catalyst for producing a pseudorandom copolymer, no polymer can be obtained. A very small amount of atactic styrene homopolymer may be obtained depending on the polymerization conditions, etc., which is understood to be formed by cationic polymerization by coexisting methylalumoxane or alkylaluminum mixed therein, or by radical polymerization. Should. Depending on the polymerization conditions and the like, the atactic polystyrene homopolymer may be contained in the copolymer of the present invention, but its amount is small, usually 10 to 5% by weight or less. As long as the transparency does not deviate from the gist of the present invention, it may be used as it is. In addition, such an atactic polystyrene homopolymer is obtained by solvent separation or the like.
It can be easily separated and removed.

The peak of the methylene carbon of the structure derived from the hetero-bond of styrene in the conventional pseudorandom copolymer having no stereoregularity is 34.0 to 34.5 ppm and 34.5.
It is known to be in two regions of ~ 35.2 ppm. (For example, Polymer Preprints,
Japan, 42 , 2292 (1993)) The styrene-ethylene copolymer of the present invention can also have a similar structure. In this case, the peak attributed to the methylene carbon of the heterogeneous bond structure derived from styrene is 34.5.
~ 35.2 ppm, but 34.0-3.
It is hardly observed at 4.5 ppm. This indicates one of the features of the copolymer of the present invention, and indicates that the phenyl group has a high stereoregularity even in a heterogeneous bond structure derived from styrene as shown in the following formula.

[0028]

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Further, the styrene-ethylene copolymer of the present invention comprises an alternating structure of ethylene and styrene having a high stereoregularity, an ethylene chain of various lengths, a heterogeneous bond of styrene, and a styrene of various lengths. It has a feature that it has various structures such as a chain of. In the styrene-ethylene copolymer of the present invention, the ratio of the alternating structure can be variously changed in the range of greater than 0.1 and less than 70 in the λ value obtained by the above formula, depending on the content of styrene in the copolymer. It is.

Since this stereoregular alternating structure is a crystallizable structure, the copolymer of the present invention can be made non-crystalline, by controlling the crystallinity by controlling the St content or by controlling the crystallinity by an appropriate method. It is possible to provide various properties such as a polymer having a partially crystalline structure. It is important that the λ value is less than 70 to keep the crystallinity of the copolymer at a low level. Therefore, the copolymer is
It is characterized by exhibiting properties as a partially crystalline or microcrystalline or non-crystalline polymer.

The copolymer of the present invention has a higher St content and a different degree of crystallinity compared to conventional styrene-ethylene copolymers having no stereoregularity and having no styrene chain. Initial tensile modulus, hardness, breaking strength,
It has improved properties such as solvent resistance, and exhibits properties characteristic of a novel part or a low-crystalline resin, a thermoplastic elastomer, or a transparent soft resin. The styrene-ethylene copolymer itself of the present invention, which does not essentially contain an elutable plasticizer or a halogen, has a basic feature of high safety.

In a copolymer having a low styrene content of 30 mol% or less, a chain structure of styrene is observed by ordinary 13 C-NMR measurement or by using styrene enriched with carbon 13. In the copolymer main chain having a low styrene content, the copolymer in which styrene chains are randomly and uniformly present has an initial modulus, breaking strength,
It has the feature of high transparency. Styrene content 1
Mol% to 15 mol%, particularly preferably 5 mol%
Not less than 15 mol%, most preferably not less than 5 mol% and not more than 10 mol%.
If it is less than mol%, the initial elastic modulus of the copolymer is high, and it is useful as a substitute for transparent soft vinyl chloride. The styrene-ethylene copolymer has been described above, but the copolymer of the present invention is not limited to this. As the aromatic vinyl compound used in the present invention, styrene and various substituted styrenes, for example, p-methylstyrene, m-methylstyrene, o-methylstyrene, ot-butylstyrene, m
-T-butylstyrene, pt-butylstyrene, p-
Examples thereof include chlorostyrene, o-chlorostyrene, α-methylstyrene and the like, and also compounds such as divinylbenzene having a plurality of vinyl groups in one molecule. Industrially, styrene, p-methylstyrene, p
-Chlorostyrene, particularly preferably styrene, is used.

In the copolymer of the present invention, olefins, conjugated or non-conjugated dienes may be added as a third component. For example, the olefins may have 3 to 2 carbon atoms.
Α-olefins of 0, ie, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene, 1-octene and cyclic olefins, ie, cyclopentene and norbornene, are preferably used, but propylene is preferably used. Examples of conjugated or non-conjugated dienes include butadiene, isoprene, 1,4-hexadiene, 1,5-hexadiene, ethylidene norbornene, dicyclopentadiene, norbornadiene, 4-vinyl-1cyclohexene, 3-vinyl-1cyclohexene, and 2-vinyl. -1 cyclohexene, 1-vinyl-1 cyclohexene, particularly preferably various vinylcyclohexenes are used.
These non-conjugated dienes introduce a cross-linking point without impairing the basic physical properties of the aromatic vinyl compound-olefin copolymer, preferably the aromatic vinyl compound-ethylene copolymer, which is the basis of the present invention. Therefore, the copolymerized amount is preferably as small as possible within a range where a practical crosslinking point density can be obtained. Preferably, 0.
01 to 20 mol% or less, more preferably 0.01 to 1
0 mol% or less, most preferably 0.01 to 3 mol% or less. When an olefin other than ethylene is used for the copolymer, a styrene-ethylene-propylene copolymer, a styrene-ethylene-1-hexene copolymer,
Styrene-ethylene-1-octene copolymer is preferred.

The copolymer is synthesized from an aromatic vinyl compound and an olefin monomer using a polymerization catalyst comprising a crosslinked metallocene compound and a cocatalyst. As the bridged metallocene compound to be used, preferably, a metallocene compound represented by the following general formula (1) is used.

[0035]

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In the formula, A and B represent an unsubstituted or substituted cyclopentaphenanthryl group (Chemical Formulas 10 and 11) and an unsubstituted or substituted benzoindenyl group (Chemical Formulas 12, 13 and 1).
4), an unsubstituted or substituted cyclopentadienyl group (Formula 15), an unsubstituted or substituted indenyl group (Formula 1)
6) or an unsubstituted or substituted fluorenyl group
7) wherein at least one of A and B is a group selected from an unsubstituted or substituted cyclopentaphenanthryl group or an unsubstituted or substituted benzoindenyl group, and A and B are Not the same structure.

[0037]

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[0038]

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[0039]

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[0040]

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[0041]

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[0042]

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[0043]

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[0044]

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(In the above formulas (10) to (17), R1 to R
Each of the eight groups is hydrogen, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkylaryl group having 7 to 20 carbon atoms, a halogen atom, an OSiR ₃ group, a SiR ₃ group, or a PR ₂ group (R Each represents a hydrocarbon group having 1 to 10 carbon atoms), and R1s, R2s, R3s,
R4, R5, R6, R7, and R8 may be the same or different. In particular, A is a group selected from an unsubstituted or substituted benzoindenyl group, and B is a group selected from an unsubstituted or substituted cyclopentaphenanthryl group, an unsubstituted or substituted indenyl group or an unsubstituted or substituted fluorenyl group. Is particularly preferable for producing a copolymer excellent in transparency having a styrene content of 1 mol% or more and 10 mol% or less of the present invention.

Specific examples of the unsubstituted cyclopentaphenanthryl group include a 3-cyclopenta [c] phenanthryl group and a 1-cyclopenta [l] phenanthryl group. As an unsubstituted benzoindenyl group, 4,
5-benzo-1-indenyl, (also known as benzo (e) indenyl), 5,6-benzo-1-indenyl, 6,7-
Benzo-1-indenyl is an example of a substituted benzoindenyl group such as an α-acenaphth-1-indenyl group.

The unsubstituted cyclopentadienyl group is cyclopentadienyl, and the substituted cyclopentadienyl group is 4-aryl-1-cyclopentadienyl,
5-diaryl-1-cyclopentadienyl, 5-alkyl-4-aryl-1-cyclopentadienyl, 4-
Alkyl-5-aryl-1-cyclopentadienyl,
4,5-dialkyl-1-cyclopentadienyl, 5-
Trialkylsilyl-4-alkyl-1-cyclopentadienyl, 4,5-dialkylsilyl-1-cyclopentadienyl and the like can be mentioned.

The unsubstituted indenyl group is 1-indenyl, and the substituted indenyl group is 4-alkyl-1-indenyl, 4-aryl-1-indenyl, 4,5-dialkyl-1-indenyl, 4,6-dialkyl -1-
Indenyl, 5,6-dialkyl-1-indenyl,
4,5-diaryl-1-indenyl, 5-aryl-
1-indenyl, 4-aryl-5-alkyl-1-indenyl, 2,6-dialkyl-4-aryl-1-indenyl, 5,6-diaryl-1-indenyl, 4,
5,6-triaryl-1-indenyl and the like. Examples of the unsubstituted fluorenyl group include a 9-fluorenyl group, and examples of the substituted fluorenyl group include a 7-methyl-9-fluorenyl group and a benzo-9-fluorenyl group.

In the above general formula (2), Y represents A, B
And carbon or silicon having a substituent and hydrogen or a methylene group having a hydrocarbon group having 1 to 15 carbon atoms. The substituents may be different or the same. Y may have a cyclic structure such as a cyclohexylidene group and a cyclopentylidene group. Preferably, Y is a substituted methylene group having a bond with A and B and substituted with hydrogen or a hydrocarbon group having 1 to 15 carbon atoms. Examples of the hydrocarbon substituent include an alkyl group, an aryl group, a cycloalkyl group, and a cycloaryl group. The substituents may be different or the same. Particularly preferably, Y _{is, -CH 2 -, - CMe 2} -, - CEt
₂ -, - CPh ₂ -, cyclohexylidene, a cyclopentylidene group. Here, Me represents a methyl group, Et represents an ethyl group, and Ph represents a phenyl group. X is hydrogen, halogen, an alkyl group having 1 to 15 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkylaryl group having 8 to 12 carbon atoms, a silyl group having a hydrocarbon substituent having 1 to 4 carbon atoms, Carbon number 1
An alkoxy group having 10 to 10 or a dialkylamide group having an alkyl substituent having 1 to 6 carbon atoms. Chlorine, bromine and the like as halogen, methyl group as alkyl group,
Ethyl group and the like; aryl group and the like; phenyl group and the like; alkylaryl group and the like; benzyl group; silyl group and the like; trimethylsilyl group and the like; alkoxy group and methoxy group, ethoxy group and isopropyl group and the like; Examples of the amide group include a dimethylamide group. M is zirconium, hafnium, or titanium. Particularly preferred is zirconium. As for the complex in which a racemic body or a meso body exists, a racemic body is preferably used, but a racemic body, a mixture of meso bodies, or a meso body may be used. Further, d-form or 1-form may be used. As for the complex in which a pseudo-racemic body or a pseudo-meso form is present, a pseudo-racemic form is preferably used, but a pseudo-racemic form, a mixture of the pseudo-meso form, or a pseudo-meso form may be used.

Examples of the transition metal catalyst component include the following compounds. For example, dimethylmethylene (4,5-benzo-1-indenyl) (3-cyclopenta [c] phenanthryl) zirconium dichloride, dimethylmethylene (5,6-benzo-1-indenyl)
(3-cyclopenta [c] phenanthryl) zirconium dichloride, dimethylmethylene (6,7-benzo-1
-Indenyl) (3-cyclopenta [c] phenanthryl) zirconium dichloride, dimethylmethylene (cyclopentadienyl) (3-cyclopenta [c] phenanthryl) zirconium dichloride, dimethylmethylene (1-indenyl) (3-cyclopenta [c] phenanthryl ) Zirconium dichloride, dimethylmethylene (1-fluorenyl) (3-cyclopenta [c] phenanthryl) zirconium dichloride, dimethylmethylene (4-phenyl-1-indenyl) (3-cyclopenta [c] phenanthryl) zirconium dichloride, dimethylmethylene (4 -Naphthyl-1-indenyl) (3-
Cyclopenta [c] phenanthryl) zirconium dichloride, dimethylmethylene (3-cyclopenta [c] phenanthryl) (4,5-naphth-1-indenyl) zirconium dichloride, dimethylmethylene (3-cyclopenta [c] phenanthryl) (α-acenaphtho- 1-
Indenyl) zirconium dichloride, dimethylmethylene (4,5-benzo-1-indenyl) (1-cyclopenta [l] phenanthryl) zirconium dichloride,
Dimethylmethylene (5,6-benzo-1-indenyl)
(1-cyclopenta [l] phenanthryl) zirconium dichloride, dimethylmethylene (6,7-benzo-1
-Indenyl) (1-cyclopenta [l] phenanthryl) zirconium dichloride, dimethylmethylene (cyclopentadienyl) (1-cyclopenta [l] phenanthryl) zirconium dichloride, dimethylmethylene (1-indenyl) (1-cyclopenta [l] phenanthryl) ) Zirconium dichloride, dimethylmethylene (1-fluorenyl) (1-cyclopenta [l] phenanthryl) zirconium dichloride, dimethylmethylene (4-phenyl-1-indenyl) (1-cyclopenta [l] phenanthryl) zirconium dichloride, dimethylmethylene (4 -Naphthyl-1-indenyl) (1-
Cyclopenta [l] phenanthryl) zirconium dichloride, dimethylmethylene (1-cyclopenta [l] phenanthryl) (4,5-naphth-1-indenyl) zirconium dichloride, dimethylmethylene (1-cyclopenta [l] phenanthryl) (α-acenaphtho- 1-
Indenyl) zirconium dichloride, dimethylmethylene (1-cyclopenta [l] phenanthryl) (3-cyclopenta [c] phenanthryl) zirconium dichloride, dimethylmethylene (cyclopentadienyl)
(4,5-benzo-1-indenyl) zirconium dichloride, dimethylmethylene (1-indenyl) (4,5
-Benzo-1-indenyl) zirconium dichloride {also known as isopropylidene (1-indenyl) (4,5-
Benzo-1-indenyl) zirconium dichloride
Dimethylmethylene (1-fluorenyl) (4,5-benzo-1-indenyl) zirconium dichloride, dimethylmethylene (4-phenyl-1-indenyl) (4,5
-Benzo-1-indenyl) zirconium dichloride,
Dimethylmethylene (4-naphthyl-1-indenyl)
(4,5-benzo-1-indenyl) zirconium dichloride, dimethylmethylene (5,6-benzo-1-indenyl) (1-indenyl) zirconium dichloride,
Dimethylmethylene (6,7-benzo-1-indenyl)
(1-indenyl) zirconium dichloride, dimethylmethylene (1-indenyl) (4,5-benzo-1-indenyl) zirconium bis (dimethylamide) and the like.

In particular, A is a group selected from unsubstituted or substituted benzoindenyl groups, and B is a group selected from substituted cyclopentaphenanthryl groups, unsubstituted or substituted indenyl groups or unsubstituted or substituted fluorenyl groups. Particularly preferred examples of certain transition metal catalyst components include the following compounds. Dimethylmethylene (1-indenyl) (4,5-benzo-1-indenyl) zirconium dichloride, dimethylmethylene (1-fluorenyl) (4,5-benzo-1-indenyl) zirconium dichloride, dimethylmethylene (3-cyclopenta [c ] Phenanthryl) (4,5-benzo-1-indenyl) zirconium dichloride, dimethylmethylene (1
-Cyclopenta [l] phenanthryl) (4,5-benzo-1-indenyl) zirconium dichloride, dimethylmethylene (1-indenyl) (4,5-benzo-1-
Indenyl) zirconium bis (dimethylamide), diphenylmethylene (1-indenyl) (4,5-benzo-1-indenyl) zirconium dichloride. Although the zirconium complex has been exemplified above, the same compounds as described above are preferably used for the titanium and hafnium complexes. Further, a mixture of a racemic body and a meso body may be used. Preferably, racemic or pseudo-racemic is used. In these cases, a D-form or an L-form may be used.

As the co-catalyst used in the present invention, a co-catalyst conventionally used in combination with a transition metal catalyst component can be used. As such a co-catalyst, an aluminoxane (or alumoxane) or a co-catalyst is used. Elemental compounds are preferably used. Furthermore, the present invention is a process for producing an aromatic vinyl compound-olefin copolymer in which the cocatalyst used in this case is an aluminoxane (or alumoxane) represented by the following general formulas (5) and (6).

[0053]

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In the formula, R is an alkyl group having 1 to 5 carbon atoms, an aryl group having 6 to 10 carbon atoms, or hydrogen, and m is 2 to 10 carbon atoms.
It is an integer of 0. Each R may be the same or different.

[0055]

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In the formula, R ′ is an alkyl group having 1 to 5 carbon atoms;
An aryl group having 6 to 10 carbon atoms or hydrogen, and n is 2 to 1
It is an integer of 00. Each R 'may be the same or different. As the aluminoxane, methylalumoxane, ethylalumoxane and triisobutylalumoxane are preferably used, and methylalumoxane is particularly preferably used. If necessary, a mixture of these different alumoxanes may be used. These alumoxanes may be used in combination with alkylaluminums, for example, trimethylaluminum, triethylaluminum, triisobutylaluminum, and alkylaluminums containing halogen, for example, dimethylaluminum chloride. The addition of the alkyl aluminum is effective for removing a polymerization inhibitor such as a polymerization inhibitor in styrene, styrene, water in a solvent, and other substances that inhibit polymerization, and rendering the polymerization reaction harmless. However, by pre-distilling styrene, solvent, etc., bubbling with a dry inert gas, or reducing these amounts to a level that does not affect the polymerization by a known method such as passing through a molecular sieve,
Alternatively, slightly increase the amount of alumoxane used,
Alternatively, if it is added, it is not always necessary to add the alkyl aluminum during the polymerization. In the present invention, a boron compound can be used as a promoter together with the above transition metal catalyst component.

The boron compound used as a cocatalyst is
Triphenylcarbenium tetrakis (pentafluorophenyl) borate {trityltetrakis (pentafluorophenyl) borate}, lithium tetra (pentafluorophenyl) borate, tri (pentafluorophenyl) borane, trimethylammonium tetraphenylborate, triethylammonium tetraphenylborate , Tripropylammonium tetraphenylborate, tri (n-butyl) ammonium tetraphenylborate, tri (n-butyl) ammoniumtetra (p-
Tolyl) phenyl borate, tri (n-butyl) ammonium tetra (p-ethylphenyl) borate, tri (n-butyl) ammonium tetra (pentafluorophenyl) borate, trimethylammonium tetra (p
-Tolyl) borate, trimethylammonium tetrakis-3,5-dimethylphenylborate, triethylammonium tetrakis-3,5-dimethylphenylborate, tributylammonium tetrakis-3,5-dimethylphenylborate, tributylammonium tetrakis-2,4-dimethyl Phenyl borate, anilium tetrakis pentafluorophenyl borate, N,
N′-dimethyl anilium tetraphenyl borate,
N, N'-dimethylanilium tetrakis (p-tolyl) borate, N, N'-dimethylanilium tetrakis (m-tolyl) borate, N, N'-dimethylanilium tetrakis (2,4-dimethylphenyl) borate , N, N'-dimethylanilium tetrakis (3,5
-Dimethylphenyl) borate, N, N'-dimethylaniliumtetrakis (pentafluorophenyl) borate, N, N'-diethylanilliumtetrakis (pentafluorophenyl) borate, N, N'-2,4,5-
Pentamethylanilinium tetraphenylborate,
N, N'-2,4,5-pentaethylanilinium tetraphenylborate, di- (isopropyl) ammonium tetrakispentafluorophenylborate, di-cyclohexylammonium tetraphenylborate, triphenylphosphonium tetraphenylborate, tri (methylphenyl) ) Phosphonium tetraphenylborate, tri (dimethylphenyl) phosphonium tetraphenylborate, triphenylcarbenium tetrakis (p-tolyl) borate, triphenylcarbenium tetrakis (m-tolyl) borate, triphenylcarbenium tetrakis (2,4- Dimethylphenyl) borate, triphenylcarbeniumtetrakis (3,5-dimethylphenyl) borate, tropyliumtetrakispentafluorophenyl Borate, tropylium tetrakis (p-tolyl) borate, tropylium tetrakis (m-tolyl) borate, tropylium tetrakis (2,4-dimethylphenyl) borate, tropylium tetrakis (3,5-dimethylphenyl) borate and the like. . These boron compounds and the above-mentioned organoaluminum compounds may be used simultaneously. In particular, when a boron compound is used as a co-catalyst, the addition of an alkyl aluminum compound such as triisobutyl aluminum is effective for removing impurities such as water contained in the polymerization system that adversely affect the polymerization.

In producing the copolymer of the present invention, ethylene and an aromatic vinyl compound are brought into contact with a transition metal catalyst component, which is a metal complex, and a cocatalyst. Can be used. In producing the aromatic vinyl compound polymer of the present invention, the aromatic vinyl compound exemplified above, the transition metal catalyst component which is a metal complex, and the cocatalyst are brought into contact with each other. Can be used. As a method of the above copolymerization or polymerization, a method of polymerizing in a liquid monomer without using a solvent, or pentane, hexane, heptane, cyclohexane, benzene, toluene, ethylbenzene, xylene,
There is a method in which a saturated aliphatic or aromatic hydrocarbon such as chloro-substituted benzene, chloro-substituted toluene, methylene chloride, chloroform or the like or a halogenated hydrocarbon is used alone or in a mixed solvent. If necessary, a method such as batch polymerization, continuous polymerization, batch polymerization, slurry polymerization, preliminary polymerization, or gas phase polymerization can be used. Conventionally, when styrene is used as a monomer component, gas-phase polymerization cannot be adopted because of its low vapor pressure. However, when a catalyst composed of the transition metal catalyst component for polymerization of the present invention and a co-catalyst is used, the copolymerization ability of styrene is extremely high, so that copolymerization is possible even at a low styrene monomer concentration. That is, olefin and ethylene can be copolymerized even under a low styrene partial pressure under gas phase polymerization conditions.
In this case, the transition metal catalyst component for polymerization and the cocatalyst may be used by being supported on a suitable known carrier.

The copolymerization or polymerization temperature is suitably from -78 ° C to 200 ° C. A polymerization temperature lower than -78 ° C is industrially disadvantageous, and a temperature higher than 200 ° C is not suitable because decomposition of the metal complex occurs. Furthermore, industrially preferably, it is 0 ° C to 160 ° C, particularly preferably 30 ° C to 160 ° C.
It is. The pressure at the time of copolymerization is suitably from 0.1 to 100 atm, preferably from 1 to 30 atm, and particularly preferably from 1 to 10 atm for industrial use. When an organoaluminum compound is used as a cocatalyst, the aluminum atom / complex metal atom ratio is 0.1 to 10 with respect to the metal of the complex.
0000, preferably in a ratio of 10 to 10,000. If it is less than 0.1, the metal complex cannot be activated effectively, and if it exceeds 100,000, it is economically disadvantageous. When a boron compound is used as a promoter, a boron atom /
The complex metal is used in an atomic ratio of 0.01 to 100, preferably 0.1 to 10, particularly preferably 1. If it is less than 0.01, the metal complex cannot be activated effectively, and if it exceeds 100, it is economically disadvantageous. The metal complex and the cocatalyst may be mixed and prepared outside the polymerization tank, or may be mixed in the tank during polymerization.

The styrene-ethylene copolymer which is an example of the aromatic vinyl compound-olefin copolymer of the present invention will be described below. However, the present invention relates to styrene-
It is not limited to the ethylene copolymer.

[0061]

The present invention will be described below with reference to examples.
The present invention is not limited to the following examples. In the following description, Cp is a cyclopentadienyl group, In
d is a 1-indenyl group, BInd is 4,5-benzo-1
-Indenyl group, Flu represents a 9-fluorenyl group, Me represents a methyl group, Et represents an ethyl group, tBu represents a tertiary-butyl group, and Ph represents a phenyl group.

The copolymers obtained in each of the examples and comparative examples were analyzed by the following means. The 13C-NMR spectrum was measured using a heavy chloroform solvent or a heavy 1,1,2,2-tetrachloroethane solvent using α-500 manufactured by JEOL Ltd. with reference to TMS. Here, the measurement based on TMS is as follows.
First, the triple line 1 of tetrachloroethane based on TMS
The shift value of the center peak of the 3C-NMR peak was determined.
Next, the copolymer was dissolved in tetrachloroethane to obtain 13C.
-The NMR was measured, and each peak shift value was calculated based on the triplet center peak of tetrachloroethane. The shift value of the triplet center peak of tetrachloroethane is 73.
It was 89 ppm. Quantification of peak area 13C-
The NMR spectrum measurement was performed by a proton gate decoupling method in which NOE was eliminated, using a pulse of 45 ° pulse width and a repetition time of 5 seconds as a standard. By the way, under the same conditions, except that the repetition time was changed to 1.5 seconds, the measurement was performed.
The result was consistent with the case of the repetition time of 5 seconds within the range of the measurement error.
Determination of the styrene content in the copolymer was performed by 1H-NMR, and the equipment used was α-500 manufactured by JEOL Ltd. and AC-250 manufactured by BRUKER. Deuterated chloroform solvent or
A peak derived from a phenyl group proton (6.5) with reference to TMS using heavy 1,1,2,2-tetrachloroethane.
-7.5 ppm) and the intensity of the proton peak derived from the alkyl group (0.8-3 ppm). For the molecular weight in the examples, a weight average molecular weight in terms of standard polystyrene was determined using GPC (gel permeation chromatography). The copolymer soluble in THF at room temperature is THF
Was used as a solvent, and measurement was performed using HLC-8020 manufactured by Tosoh Corporation. The copolymer insoluble in THF at room temperature can be obtained from Waters, Inc. using 1,2,4-trichlorobenzene as a solvent.
It measured at 135 degreeC using the 0CV apparatus. The DSC measurement was performed at a temperature rising rate of 10 ° C./min under a stream of N ₂ using DSC200 manufactured by Seiko Denshi Co., Ltd. As a sample for evaluating transparency, a sheet having a thickness of 1.0 mm formed by a hot press method (temperature: 180 ° C., time: 3 minutes, pressure: 50 kg / cm ² ) was used. Hayes uses this sheet as JIS-K-
According to 7361-1, Nippon Denshoku Turbidity Meter NDH-200
0 was measured.

Example 1 <Synthesis of Copolymer> As a transition metal compound, rac-dimethylmethylene (1-indenyl) (4,5-benzo-1
-Indenyl) zirconium dichloride, Table 2
Under the conditions shown in the above, the measurement was performed as follows.

[0064]

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Polymerization was carried out using a polymerization vessel having a capacity of 150 L, a stirrer and a jacket for heating and cooling. 80 L of dehydrated cyclohexane and 5 L of dehydrated styrene were charged and heated and stirred at an internal temperature of about 40 ° C. 84 mmol of triisobutylaluminum and 840 mmol of methylalumoxane (MMAO-3A, manufactured by Tosoh Akzo) were added based on Al. Immediately, ethylene was introduced, and a pressure of 1.0 MPa (9
After stabilizing at Kg / cm ² G), the catalyst obtained in the synthesis A of the above-mentioned transition metal catalyst component, rac-dimethyl methylene (1-indenyl)
About 100 ml of a toluene solution of (4,5-benzo-1-indenyl) zirconium dichloride (84 μmol) and 2 mmol of triisobutylaluminum were added to the polymerization vessel. Heat generation started immediately, and cooling water was introduced into the jacket. The internal temperature is up to 7 about 10 minutes after the start of polymerization.
After the temperature rose to 1 ° C., polymerization was carried out for 3.0 hours while maintaining the temperature at about 70 ° C. and maintaining the pressure at 1.0 MPa. After completion of the polymerization, the obtained polymerization solution was degassed, and then treated by the crumb forming method as described below to recover the polymer. A dispersant (Pluronic:
Was added to 300 L of heated water at 85 ° C. over 1 hour. Then, after stirring at 97 ° C. for 1 hour, hot water containing crumbs was poured into cold water to collect crumbs.
The crumb was air-dried at 50 ° C. and then vacuum degassed at 80 ° C. to obtain 7.5 kg of a polymer having a crumb shape of about several mm and having a good shape. In addition, a part of the polymerization solution was withdrawn from the polymerization vessel as it was, and was poured little by little into excess vigorously stirred methanol to precipitate the produced polymer.
It was dried under reduced pressure at 80 ° C. until no change in weight was observed. The polymer recovered by this method was press-molded and the haze was measured.

Example 2 <Synthesis of copolymer> As a transition metal compound, rac-dimethylmethylene (1-indenyl) (4,5-benzo-1
-Indenyl) zirconium dichloride, Table 2
Under the conditions shown in the above, the measurement was performed as follows. Polymerization was carried out using an autoclave having a capacity of 10 L, a stirrer and a jacket for heating and cooling. 4000 ml of dehydrated toluene and 800 ml of dehydrated styrene were charged and heated and stirred at an internal temperature of 50 ° C. The system was purged by bubbling about 100 L of nitrogen, and 8.4 mmol of triisobutylaluminum was further added.
l, Methylalumoxane (Tosoh Akzo Co., Ltd., MMA
O) was added in an amount of 84 mmol based on Al. Immediately introduce ethylene, pressure 1.1MPa (10Kg / cm ² G)
Then, about 50 ml of a toluene solution of 8.4 μmol of a transition metal compound and 0.84 mmol of triisobutylaluminum was added to the autoclave from a catalyst tank installed on the autoclave. 50 internal temperature
Polymerization was carried out for 2 hours while maintaining the pressure at 1.1 ° C. and a temperature of 1.1 MPa. After the completion of the polymerization, the resulting polymerization solution was poured little by little into excess methanol which was vigorously stirred to precipitate the produced polymer. The polymer was dried under reduced pressure at 80 ° C. until no change in weight was observed. As a result, 700 g of a polymer was obtained.

Example 3 <Synthesis of styrene polymer>
Polymerization was carried out using -dimethylmethylene (1-indenyl) (4,5-benzo-1-indenyl) zirconium dichloride under the following conditions. In a glove box, 10 ml of styrene, 1 mmol of TIBA, MM were placed in a 120 ml glass container (with a magnetic stirrer).
8.4 mmol of AO was charged. 16 ml of toluene containing 4.6 μmol of the transition metal compound was added to this solution,
Stir at room temperature for 3 hours. The polymer solution was added little by little into a large excess of hydrochloric acid-methanol to precipitate the produced polymer. As a result, about 0.5 g of a polymer was obtained. 13C-NM
As a result of R, DSC, and XRD measurements, it was confirmed to be isotactic polystyrene. The weight average molecular weight (Mw) obtained by GPC measurement was 20,000, and the molecular weight distribution (Mw / Mn) was 1.9. 1,1,
13C-N determined with reference to the center peak (73.89 ppm) of the triplet of 2,2-tetrachloroethane-d2
The peak shift values of MR were as follows.

[0068]

[Table 1]

The melting point obtained by DSC measurement was 220 ° C.
Met.

Comparative Examples 1 to 5 Using the following transition metal compounds and under the conditions shown in Table 2,
Polymerization was carried out in the same manner as in Example 2. CGCT (constrained geometric structure) type Ti complex (tertiary butylamide) dimethyl (tetramethyl-η5-cyclopentadienyl) silane titanium dichloride, rac-ethylenebis (1-indenyl) zirconium dichloride, rac-dimethylsilylenebis (2 -Methyl-4-phenyl-1-indenyl) zirconium dichloride, diphenylmethylene (fluorenyl) (cyclopentadienyl) zirconium dichloride.

Table 2 shows the polymerization conditions and results of each example.

[0072]

[Table 2]

Table 3 shows the composition of the obtained polymer, the molecular weight determined by GPC, and the results of the glass transition point and melting point determined by DSC.

[0074]

[Table 3]

FIG. 1 shows a GP of the copolymer obtained in Example 2 as a typical example of the styrene-ethylene copolymer of the present invention.
The C chart is shown. The peak obtained was a single peak having a single peak. In the GPC measurement of the polymer obtained in each example, as shown in FIG. 1, different detectors (RI and U) were used.
The fact that the GPC curves obtained in V) coincide with each other within the error range of the experiment indicates that the present copolymer is a very uniform copolymer having a small composition distribution. The single glass transition point obtained by DSC in Table 3 also indicates a uniform composition of the copolymer of the present invention.

The transparent styrene-ethylene copolymer of the present invention is specifically a copolymer mainly containing a typical structure represented by the following general formula at an arbitrary ratio. 13C-NM
The methine and methylene carbon regions of the R spectrum show peaks that can be assigned to the following. a to o are symbols indicating carbons shown in the following chemical structural formulas of Chemical Formulas 21 to 30.
The central peak of the triplet of heavy tetrachloroethane (73.8
The following peaks are shown based on 9 ppm). (1) Alternating structure of styrene and ethylene

[0077]

Embedded image

(In the formula, Ph represents a phenyl group, x represents the number of repeating units, and represents an integer of 2 or more.)

That is, a structure consisting of a methine carbon connected to a Ph group and three methylene carbons sandwiched between the methine carbons, which can be represented by the following formula, is shown.

[0080]

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General formula (for simplicity, hydrogen atom is omitted.) (2) Chain structure of ethylene

[0082]

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(3) Structure consisting of an ethylene chain and one unit of styrene

[0084]

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(4) Structure composed of styrene unit inversion (tail-to-tail structure)

[0086]

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(5) a structure comprising an ethylene unit or a head-tail chain of two ethylene chains and two styrene units;

[0088]

Embedded image

Or a structure in which a styrene unit and a styrene-ethylene alternate structural unit are randomly bonded.

[0090]

Embedded image

Alternating structure unit

[0092]

Embedded image

[0093]

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(6) Structure comprising a head-tail chain of three or more styrene units

[0095]

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25.1 to 25.2 ppm (c) 36.4 to 36.5 ppm (b) 44.8 to 45.4 ppm (a) 29.4 to 29.9 ppm (g) 36.5 to 36.8 ppm (E) 27.2 to 27.6 ppm (f) 45.4 to 46.1 ppm (d, h) 34.5 to 34.9 ppm (i) 42.3 to 43.1 ppm (j) 43.7 to 44 5.5 ppm (k) 35.6-36.1 ppm (l) 24.0-24.9 ppm (m) 40.5-41.0 ppm (n) 43.0-43.6 ppm (o) A slight shift, a microstructure of a peak, or a peak shoulder may occur due to the influence of measurement conditions, a solvent, or the like, or a long-range effect from an adjacent structure.

These peaks were assigned by Macromo
recules, 13 , 849 (1980), Stu
f. Surf. Sci. Catal. , 517,199
0, J.P. Appl. Polymer Sci. , 53 ,
1453 (1994); Polymer Phys
s. Ed. , 13 , 901 (1975), Macrom.
olecules, 10 , 773 (1977), European Patent 416815, Japanese Patent Application Laid-Open No. 4-130114, 13C-NMR Inadequate method,
DEPT method and 13C-NMR database STN
(Specinfo) peak shift prediction.

[0098]

[Table 4]

The structural index λ of the copolymer obtained in each Example
And the isotactic dyad fraction m value of the styrene unit-ethylene unit alternating structure were determined according to the above formulas (i) and (ii), respectively. It is shown in Table 4.

Table 5 shows the haze values of the copolymers obtained in the examples and comparative examples. It can be seen that all of the copolymers of the present invention show a low haze value and have high transparency.

[0101]

[Table 5]

[0102]

According to the present invention, a low haze value is obtained,
A transparent aromatic vinyl compound-ethylene copolymer having high transparency can be obtained.

[Brief description of the drawings]

FIG. 1 shows a GPC chart of the copolymer obtained in Example 2 as a typical example of the styrene-ethylene copolymer of the present invention.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4J028 AA01A AB00A AB01A AC01A AC08A AC09A AC10A AC26A AC27A AC28A BA00A BA01B BA02B BA03B BB00A BB01B BB02B BC12B BC15B BC16B BC25B CB64B CB65 EB13 EB65 EB13 EB04 EC02 EC04 FA01 FA04 FA07 GA01 GA06 GA14 GA19 4J100 AA02P AB02Q CA04 CA11 DA04 DA62 FA10

Claims (5)

[Claims] 1. A transparent aromatic vinyl compound-ethylene copolymer satisfying the following conditions. (1) The content of the aromatic vinyl compound is from 1 mol% to 30 mol%. (2) The stereoregularity of the phenyl group in the alternating structure of the aromatic vinyl compound represented by the following general formula (1) and ethylene contained in the copolymer structure is 0.75 in isotactic dyad fraction m. Greater than. Embedded image (In the formula, Ph represents an aromatic group such as a phenyl group, and x represents the number of repeating units and represents an integer of 2 or more.) (3) A molded article having a thickness of 1.0 mm has a haze of 40%.
Less than. 2. The transparent aromatic vinyl compound according to claim 1, which is obtained by a homopolymerization of styrene using a catalyst capable of producing polystyrene having isotactic stereoregularity. -An ethylene copolymer. 3. The transparent aromatic vinyl compound-ethylene copolymer according to claim 2, wherein the molecular weight distribution (Mw / Mn) is 3 or less. 4. The transparent aromatic vinyl compound according to claim 1, which has a head-tail chain structure of two or more aromatic vinyl compound units.
Ethylene copolymer. 5. The method according to claim 1, wherein the aromatic vinyl compound and ethylene are polymerized using a polymerization catalyst comprising a transition metal compound represented by the following general formula (2) and a co-catalyst. 3. The method for producing a transparent aromatic vinyl compound-ethylene copolymer according to claim 1. Embedded image In the formula, A and B represent an unsubstituted or substituted cyclopentaphenanthryl group, an unsubstituted or substituted benzoindenyl group,
A group selected from an unsubstituted or substituted cyclopentadienyl group, an unsubstituted or substituted indenyl group or an unsubstituted or substituted fluorenyl group, wherein at least one of A and B is an unsubstituted or substituted cyclopentaphenanthryl group Or a group selected from an unsubstituted or substituted benzoindenyl group, and A and B are not the same structure. Y is a methylene or silylene group or an ethylene group which has a bond with A and B and additionally has hydrogen or a hydrocarbon group having 1 to 15 carbon atoms. The substituents may be different or the same. Y may have a cyclic structure such as a cyclohexylidene group and a cyclopentylidene group. X is hydrogen, halogen, an alkyl group having 1 to 15 carbon atoms, an aryl group having 6 to 10 carbon atoms, an alkylaryl group having 8 to 12 carbon atoms, a silyl group having a hydrocarbon substituent having 1 to 4 carbon atoms, An alkoxy group having 1 to 10 carbon atoms or a dialkylamide group having an alkyl substituent having 1 to 6 carbon atoms. M is zirconium, hafnium, or titanium.