JP2810098B2 - Styrene-based copolymer and its production method - Google Patents

Description

The present invention relates to a styrenic copolymer and a method for producing the same,
More specifically, the present invention relates to a copolymer having a specific steric structure composed of a styrene-based monomer and a diene-based monomer, and an efficient production method thereof.

[Problems to be solved by conventional technology and invention]

Conventionally, a styrene-based polymer produced by a radical polymerization method or the like has a three-dimensional structure having an atactic structure, and various molding methods such as injection molding, extrusion molding, hollow molding, vacuum molding, and injection molding. Depending on the method, it is formed into various shapes and widely used as household electrical appliances, office equipment, household goods, packaging containers, toys, furniture, synthetic paper and other industrial materials.

However, such a styrenic polymer having an atactic structure has a disadvantage that heat resistance and chemical resistance are inferior.

By the way, the group of the present inventors has recently succeeded in developing a styrene-based polymer having high syndiotacticity, and further developed a styrene-based polymer obtained by copolymerizing this styrene monomer and other components ( JP-A-62-10
Nos. 4818 and 63-241009). These syndiotactic polymers or copolymers have heat resistance,
It is excellent in chemical resistance and electrical specialty, and is expected to be applied in various fields.

However, the above polymers, especially syndiotactic polystyrene, have a glass transition temperature of 90 to 100 ° C and a melting point of 250 to
It is a polymer of 275 ° C, and its characteristics cannot be fully obtained unless the injection molding temperature is set high.There is also room for improvement in the flexibility of molded products molded with high-temperature molds. Have been.

By the way, in order to improve the properties of styrenic polymers having a syndiotactic structure, it has been proposed to combine them with other thermoplastic resins and inorganic fillers. However, the adhesiveness and compatibility of their interfaces are still improved. Room was left.

Thus, the present inventors have improved the glass transition temperature while maintaining the heat resistance and chemical resistance of syndiotactic polystyrene, and enabled low-temperature injection molding, and also with other resins and inorganic fillers. Intensive research was conducted to develop a copolymer having improved compatibility and adhesion, improved wettability, and an efficient production method thereof.

[Means for solving the problem]

As a result, when a styrene-based monomer and a diene-based monomer are copolymerized in the presence of a specific catalyst, a copolymer having a structure in which a diene component is copolymerized with a styrene-based repeating unit chain having a syndiotactic structure is generated. The copolymer is excellent in heat resistance, chemical resistance, etc., and has a low glass transition temperature, enabling low-temperature injection molding, and exhibits good wettability, and can achieve the desired modification. I found that. The present invention has been completed based on such findings.

That is, the present invention provides a compound represented by the general formula [I]: [Wherein R ¹ is a hydrogen atom, a halogen atom or
Or less hydrocarbon groups, and m represents an integer of 1 to 3.
When m is plural, each R ¹ may be the same or different. A styrene-based repeating unit [I] and a diene-based repeating unit [II], wherein the diene-based repeating unit [I
I] of 0.1 to 50% by weight and 1,2,4-
Intrinsic viscosity measured in trichlorobenzene is 0.07-20dl
/ g, and a styrenic copolymer characterized in that the stereoregularity of the styrenic repeating unit chain is mainly a syndiotactic structure. Wherein R ¹ and m are the same as above. ] The styrene-based monomer and diene-based monomer represented by the formula are copolymerized in the presence of a catalyst comprising a titanium compound and an alkylaluminoxane.

The styrene-based copolymer of the present invention comprises the repeating unit [I] represented by the general formula [I] and the diene-based repeating unit [II] as described above, wherein the repeating unit represented by the general formula [I] is used. Is derived from the styrenic monomer represented by the general formula [I ']. In the formula, R ¹ is a hydrogen atom, a halogen atom (eg, chlorine, bromine, fluorine, iodine)
Alternatively, a hydrocarbon group having 20 or less carbon atoms, preferably having 10 to 1 carbon atoms (eg, a methyl group, an ethyl group, a propyl group,
A saturated hydrocarbon group (especially an alkyl group) such as a butyl group, a pentyl group, and a hexyl group; or an unsaturated hydrocarbon group such as a vinyl group. Specific examples of the repeating unit [I] represented by the general formula [I] include styrene units; p-methylstyrene units; m-methylstyrene units; o-methylstyrene units; 2,4-dimethylstyrene units; 3,4-dimethylstyrene unit; 3,5-dimethylstyrene unit; 3,5-dimethylstyrene unit; p-ethylstyrene unit; m-ethylstyrene unit; alkylstyrene units such as p-tert-butylstyrene unit, p- Divinylbenzene unit; m-divinylbenzene unit; trivinylbenzene unit; p-chlorostyrene unit; m-chlorostyrene unit; o-chlorostyrene unit; p-bromostyrene unit; m-bromostyrene unit; o
-Bromostyrene unit; p-fluorostyrene unit; m-fluorostyrene unit; o-fluorostyrene unit; halogenated styrene unit such as o-methyl-p-fluorostyrene unit, or a mixture of two or more of these. can give.

On the other hand, the diene-based repeating unit [II] is derived from various diene-based monomers. Here, the diene monomer is not particularly limited, but can be broadly classified into a conjugated linear diene monomer, a non-conjugated linear diene monomer, a conjugated cyclic diene monomer, and a non-conjugated cyclic diene monomer. Of these, the conjugated linear diene monomer has the general formula [In the formula, R ² and R ³ each represent a hydrogen atom, an alkyl group, an aryl group or a halogen atom, and R ⁴ represents a hydrogen atom or a saturated hydrocarbon group having 6 or less carbon atoms. ], Specifically, 1,3-butadiene and isoprene; alkyl-substituted butadienes such as 1,3-pentadiene, 1- or 2-aryl-1,3-butadiene; 1-
Or 2-phenyl-1,3-butadiene; 2-phenyl-
Aryl-substituted butadienes such as 3-methyl-1,3-butadiene, 2-chloro-1,3-butadiene; 2-fluoro-
There are halogen-substituted butadienes such as 1,3-butadiene, and the non-conjugated linear diene-based monomers include 1,4-pentadiene; 1,5-hexadiene; and 1,7-octadiene. As diene monomers,
1,3-cyclohexadiene; 1,3-cyclooctadiene;

Examples of the non-conjugated cyclic diene-based monomer include norbornane; 1,5-cyclooctadiene; and 5-vinylnorbornene.

Among them, it is desirable to use a conjugated linear diene monomer and a non-conjugated cyclic diene monomer.

In the copolymer of the present invention, the diene-based monomer is polymerized to form a diene-based repeating unit, and the diene-based repeating unit is, for example, a conjugated linear diene-based monomer represented by the general formula (II ′). If it consists of 1,2 polymerization type and general formula There is a 1,4 polymerization type represented by

In the polymerization, from the 1,2 polymerization type, this diene-based repeating unit is either syndiotactic, isotactic, or atactic, or a mixture thereof. Cis-type and trans-type monomers are obtained, and in the polymerization of non-conjugated cyclic diene-based monomers, there is a transannular three-dimensional structure. However, in the present invention, the diene-based repeating unit [II] may have any three-dimensional structure as long as the syndiotacticity of the styrene chain is not affected.

In the copolymer of the present invention, the repeating unit [I] may be composed of two or more kinds of components. In this respect, the same applies to the repeating unit [II]. Therefore, it becomes possible to synthesize a binary, ternary or quaternary copolymer. The content of the repeating unit [II] is usually 0.1 to 50% by weight, preferably 1.0 to 20% by weight of the whole copolymer.
% By weight. If the repeating unit [II] is less than 0.1% by weight, the desired improvement effects of the present invention, such as a decrease in glass transition temperature and an improvement in flexibility, cannot be achieved. On the other hand, if it exceeds 50% by weight, the crystallization is inhibited, the chemical resistance characteristic of the styrene-based polymer having a syndiotactic structure is impaired, and the polymer becomes brittle and has the same physical properties as ordinary diene-based polymers. Defects develop.

The molecular weight of this copolymer generally has an intrinsic viscosity of 0.07 as measured in a 1,2,4-trichlorobenzene solution (135 ° C.).
2020 dl / g, preferably 0.3 to 10 dl / g. If the intrinsic viscosity is less than 0.07 dl / g, the mechanical properties are low and cannot be put to practical use. When the intrinsic viscosity exceeds 20 dl / g, ordinary melt molding becomes difficult.

In the present invention, a third component may be added within a range that does not significantly impair the properties of the obtained copolymer or the syndiotactic structure in the chain of the repeating unit [I]. Examples of such compounds include vinyl siloxanes, α-olefins, unsaturated carboxylic esters, acrylonitriles, N-substituted maleimides, and the like.

The styrenic copolymer of the present invention has a repeating unit (I),
That is, a chain of styrene-based repeating units mainly has a syndiotactic structure. Here, mainly the syndiotactic structure in the styrene-based polymer is
The stereochemical structure is mainly a syndiotactic structure, that is, a stereostructure in which a phenyl group or a substituted phenyl group which is a side chain with respect to a main chain formed from carbon-carbon bonds is alternately located in the opposite direction, Its tacticity is quantified by nuclear magnetic resonance ( ¹³ C-NMR) using isotope carbon. Tacticity measured by the ¹³ C-NMR method can be represented by the abundance ratio of a plurality of continuous structural units, for example, a dyad for two, a triad for three, and a pentad for five. However, the styrenic copolymer mainly having a syndiotactic structure referred to in the present invention is usually 75% or more, preferably 85% or more as a dyad in a chain of styrene-based repeating units, or pentad (racemic pentad) Indicates a substance having a syndiotacticity of 30% or more, preferably 50% or more. However, the degree of syndiooctity varies slightly depending on the type of the substituent and the content of the repeating unit [II].

The copolymer of the present invention as described above has a repeating unit [I],
An embodiment having desired stereoregularity and reactive substituents by copolymerization of a monomer corresponding to [II], and by applying a separation, blending or organic synthesis method using the obtained copolymer as a raw material. Can be manufactured.

Among them, according to the production method of the present invention described above, a styrene-based copolymer with higher efficiency and higher quality can be obtained.

The raw material monomers used in the production method of the present invention are a styrene monomer and a diene monomer represented by the general formula [I ']. The styrene-based monomer and the diene-based monomer are copolymerized to form a repeating unit [I],
Construct [II]. Therefore, specific examples of the styrene-based monomer and diene-based monomer include those corresponding to the specific examples of the above-mentioned repeating units [I] and [II].

In the method of the present invention, these styrene-based monomers and diene-based monomers are used as raw materials and copolymerized in the presence of a catalyst containing (A) a titanium compound and (B) an alkylaluminoxane as main components. The catalyst used is as described in detail in JP-A-63-241009. First, there are various titanium compounds as the component (A), but preferably, the general formula TiR ⁵ _a R ⁶ _b R ⁷ _c R ⁸ _{4- (a + b + c)} (α) or TiR ⁵ _d R ⁶ _e R ⁷ _{3- (d + e} ) (β) wherein R ⁵ , R ⁶ , R ⁷ and R ⁸ are each hydrogen and have 1 to 1 carbon atoms.
20 alkyl groups, C1-20 alkoxy groups, C6-20 aryl groups, alkylaryl groups, arylalkyl groups, C1-20 acyloxy groups, cyclopentadienyl groups, substituted cyclopentadiene It represents an enyl group, an indenyl group or a halogen. a, b, c are each 0 to 4
And d and e each represent an integer of 0 to 3. And at least one compound selected from the group consisting of titanium compounds and titanium chelate compounds.

R ⁵ , R ⁶ , R ⁷ and R ^{8 in the} general formula (α) or (β)
Represents a hydrogen atom and an alkyl group having 1 to 20 carbon atoms (specifically, methyl, ethyl, propyl, butyl, amyl, isoamyl, isobutyl, octyl, 2-
An ethylhexyl group, etc.), an alkoxy group having 1 to 20 carbon atoms (specifically, methoxy, ethoxy, propoxy,
A butoxy group, an amyloxy group, a hexyloxy group, a 2-ethylhexyloxy group, an aryloxy group having 6 to 20 carbon atoms (such as a phenoxy group), an aryl group having 6 to 20 carbon atoms, an alkylaryl group, an arylalkyl group ( Specifically, a phenyl group, a tolyl group, a xylyl group, a benzyl group, etc.), an acyloxy group having 1 to 20 carbon atoms (specifically, a heptadecylcarbonyloxy group, etc.), a cyclopentadienyl group, a substituted cyclopentadienyl Groups (specifically, methylcyclopentadienyl group, 1,2-dimethylcyclopentadienyl group, pentamethylcyclopentadienyl group, etc.), indenyl group, and halogen (chlorine, bromine, iodine or fluorine). These R ⁵ , R ⁶ , R ⁷ and R ⁸ may be the same or different. And a, b,
c represents an integer of 0 to 4, and d and e each represent 0
Represents an integer of 1 to 3.

More preferably, the general formula TiRXYZ (γ) wherein R represents a cyclopentadienyl group, a substituted cyclopentadienyl group or an indenyl group, X, Y and Z each independently represent a hydrogen atom, An alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 20 carbon atoms, an aryloxy group having 6 to 20 carbon atoms, an arylalkyl group having 6 to 20 carbon atoms or a halogen atom. Show. ] It is a titanium compound represented by these. The substituted cyclopentadienyl group represented by R in the formula has, for example, 1 to 1 carbon atoms.
A cyclopentadienyl group substituted by one or more alkyl groups, specifically, a methylcyclopentadienyl group,
-Dimethylcyclopentadienyl group, pentamethylcyclopentadienyl group and the like. X, Y and Z each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms (specifically, a methyl group, an ethyl group, a propyl group, an n-butyl group,
Isobutyl, amyl, isoamyl, octyl, 2,
-Ethylhexyl group), an alkoxy group having 1 to 12 carbon atoms (specifically, a methoxy group, an ethoxy group, a propoxy group,
Butoxy group, amyloxy group, hexyloxy group, octyloxy group, 2-ethylhexyloxy group, etc., aryl group having 6 to 20 carbon atoms (specifically, phenyl group, naphthyl group, etc.), aryl having 6 to 20 carbon atoms It represents an oxy group (specifically, a phenoxy group or the like), an arylalkyl group having 6 to 20 carbon atoms (specifically, a benzyl group) or a halogen atom (specifically, chlorine, bromine, iodine or fluorine).

Specific examples of the titanium compound represented by the general formula (γ) include cyclopentadienyltrimethyltitanium, cyclopentadienyltriethyltitanium, cyclopentadienyltripropyltitanium, cyclopentadienyltributyltitanium, methylcyclo Pentadienyltrimethyltitanium, 1,2-dimethylcyclopentadienyltrimethyltitanium, pentamethylcyclopentadienyltrimethyltitanium, pentamethylcyclopentadienyltriethyltitanium, pentamethylcyclopentadienyltripropyltitanium, pentamethylcyclopenta Dienyltributyltitanium, cyclopentadienylmethyltitanium dichloride, cyclopentadienylethyltitanium dichloride, pentamethylcyclopentadienylmethyltitanium dichloride, pentamethyl Cyclopentadienylethyl titanium dichloride, cyclopentadienyl dimethyl titanium monochloride, cyclopentadienyl diethyl titanium monochloride, cyclopentadienyl titanium trimethoxide, cyclopentadienyl titanium triethoxide, cyclopentadienyl titanium trichloride Propoxide, cyclopentadienyl titanium triphenoxide, pentamethylcyclopentadienyl titanium trimethoxide, pentamethylcyclopentadienyl titanium triethoxide, pentamethylcyclopentadienyl titanium tripropoxide, pentamethylcyclopentadienyl Titanium tributoxide, pentamethylcyclopentadienyl titanium triphenoxide, cyclopentadienyl titanium trichloride,
Pentamethylcyclopentadienyl titanium trichloride, cyclopentadienyl methoxy titanium dichloride,
Cyclopentadienyldimethoxytitanium chloride, pentamethylcyclopentadienylmethoxytitanium dichloride, cyclopentadienyltribenzyltitanium, pentamethylcyclopentadienylmethyldiethoxytitanium,
Examples include indenyl titanium trichloride, indenyl titanium trimethoxide, indenyl titanium triethoxide, indenyl trimethyl titanium, indenyl tribenzyl titanium and the like.

Among these titanium compounds, compounds containing no halogen atom are preferable, and in particular, titanium compounds having one π-electron ligand as described above are preferable.

On the other hand, the alkylaluminoxane, which is the component (B) used together with the titanium compound, is a reaction product of an alkylaluminum compound and water, and specifically has a general formula [In the formula, n represents a degree of polymerization, a number of 2 to 50, and R ⁹ represents an alkyl group having 1 to 8 carbon atoms. A chain alkylaluminoxane represented by the general formula And a cyclic alkylaluminoxane having a repeating unit represented by

In general, a contact product of an alkyl laminoxane such as a trialkylaluminum and water is mixed with the above-described chain alkylaluminoxane or cyclic alkylaluminoxane, unreacted trialkylaluminum, a mixture of various condensation products, and furthermore, Are complexly associated molecules, and these are various products depending on the contact conditions between the trialkylaluminum and water.

The reaction between the alkyl aluminum and water at this time is not particularly limited, and may be performed according to a known method. For example, a method of dissolving an alkyl aluminum in an organic solvent and bringing it into contact with water, a method of initially adding an alkyl aluminum during polymerization, and a method of adding water later,
Further, there is a method in which water of crystallization contained in a metal salt or the like, or water adsorbed on an inorganic substance or an organic substance is reacted with alkyl aluminum. The above water contains ammonia,
Amines such as ethylamine, sulfur compounds such as hydrogen sulfide, and phosphorus compounds such as phosphite may be contained up to about 20%.

As the alkylaluminoxane used as the component (B), when a hydrated compound or the like is used after the above-mentioned contact reaction, the solid residue is separated by filtration, and the filtrate is subjected to a temperature of 30 to 200 ° C. under normal pressure or reduced pressure. It is preferable that the mixture is heat-treated at a temperature of preferably 40 ° C to 150 ° C for 20 minutes to 8 hours, preferably 30 minutes to 5 hours while distilling off the solvent. In this heat treatment, the temperature may be appropriately determined depending on various conditions, but is usually in the above range. In general, when the temperature is lower than 30 ° C., no effect is exhibited. When the temperature is higher than 200 ° C., thermal decomposition of aluminoxane itself occurs, which is not preferable. Depending on the treatment conditions of the heat treatment, the reaction product is obtained as a colorless solid or solution. The product thus obtained can be dissolved or diluted with a hydrocarbon solvent, if necessary, and used as a catalyst solution.

A preferred example of such an alkylaluminoxane has a high magnetic field component of 50% or less in a methyl proton signal region based on an aluminum-methyl group (Al-CH ₃ ) bond observed by proton nuclear magnetic resonance absorption. . That is, when the above contact product is observed for proton nuclear magnetic resonance ( ¹ H-NMR) spectrum in a toluene solvent at room temperature, the methyl proton signal based on Al—CH ₃ is based on tetramethylsilane (TMS). In the range of 1.0 to -0.5 ppm. TMS proton signal (0 ppm) is Al-C
Because of the methyl protons observation area based on H _3, the Al-
The methyl proton signal based on CH ₃ was measured with reference to 2.35 ppm of the methyl proton signal of toluene based on TMS, and a high magnetic field component (ie, −0.1 to −0.5 ppm) and another magnetic field component (that is, 1.0 to −0.5 ppm) were measured. 0.1ppm)
Those having a high magnetic field component of 50% or less, preferably 45 to 5% of the whole can be suitably used as the component (B) of the catalyst of the present invention.

The catalyst used in the method of the present invention comprises the above-mentioned components (A) and (B) as main components. In addition to the above, other catalyst components, for example, a general formula AlR ¹⁰ ₃ [wherein R ¹⁰ represents an alkyl group having 1 to 8 carbon atoms. ], Or other organometallic compounds represented by the formula (1).

In using this catalyst, the ratio of the component (A) to the component (B) in the catalyst depends on the type of each component and the styrene-based monomer and the diene-based monomer represented by the general formula [I '] as a raw material. Although it depends on the kind and other conditions and cannot be unambiguously determined, usually, the ratio of aluminum in the component (B) to titanium in the component (A), that is, aluminum / titanium (molar ratio) is 1 to 10 ^6. , Preferably 10
~ 10 ⁴ .

In the method of the present invention, the styrene-based monomer and the diene-based monomer represented by the above general formula [I '] are copolymerized in the presence of a catalyst containing the above-mentioned components (A) and (B) as main components. This copolymerization can be carried out by various methods such as bulk polymerization, solution polymerization and suspension polymerization. Solvents that can be used in the copolymerization include aliphatic hydrocarbons such as pentane, hexane and heptane, alicyclic hydrocarbons such as cyclohexane and aromatic hydrocarbons such as benzene, toluene and xylene. The polymerization temperature is not particularly limited, but is usually 0 to 100 ° C., preferably 10 to 100 ° C.
~ 70 ° C. The polymerization time is 5 minutes to 24 hours, preferably 1 hour or more.

Further, in order to adjust the molecular weight of the obtained styrenic copolymer, it is effective to carry out the copolymerization reaction in the presence of hydrogen.

The styrenic copolymer obtained by the method of the present invention has high syndiotacticity of a styrenic repeating unit chain, but after polymerization, if necessary, is subjected to deashing treatment with a washing solution containing hydrochloric acid or the like, After washing and drying under reduced pressure, the residue is washed with a solvent such as methyl ethyl ketone to remove soluble components, and a high-purity styrene-based copolymer having extremely large syndiotacticity can be obtained.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

Example 1 (1) of methylaluminoxane toluene 200ml glass vessel was purged with argon internal volume 500ml of hydrochloric copper pentahydrate _{(CuSO 4 · 5H 2 O)} 17.7g (71 mmol) and trimethyl aluminum 24 ml (250 mmol ) Was added and reacted at 40 ° C. for 8 hours. Thereafter, the solid component was removed, and toluene was further distilled off from the resulting solution under reduced pressure to obtain 6.7 g of a contact product. Its molecular weight measured by the freezing point depression method was 610.

Also, when the proton nuclear magnetic resonance spectrum of a high magnetic field component by the above-mentioned ¹ H-NMR measurement, that is, its proton nuclear magnetic resonance spectrum is observed in a toluene solution at room temperature, the methyl proton signal based on the (Al—CH ₃ ) bond is found to be tetramethylsilane. It is found in the range of 1.0 to -0.5 ppm by standard. For proton signal of tetramethylsilane which is (0 ppm) is in the observation area of the methyl proton based on the Al-CH ₃ bonds, this
The methyl proton signal based on the Al-CH ₃ bond was measured with reference to 2.35 ppm of the methyl proton signal of toluene based on tetramethylsilane, and the high magnetic field component (i.e., -0.1 to -0.5 ppm) and other magnetic field components (i.e., 1.0 ~
-0.1 ppm), the high magnetic field component
%Met.

(2) Production of styrene-1,3-butadiene copolymer 100 ml of styrene was placed in a reaction vessel having an internal volume of 1.0 and equipped with a stirrer.
And 6.0 mmol of the methylaluminoxane obtained in the above (1) as an aluminum atom was added.
For a minute. Next, 56.3 g of 1,3-butadiene was sampled into a stainless steel catalyst charging tube which had been sufficiently purged with nitrogen in advance, and was added to the reaction system.At the same time, pentamethylcyclopentadienyl titanium trimethoxide was converted to titanium atoms.
0.03 mmol was added, and polymerization was carried out at 40 ° C. for 5 hours with stirring. After completion of the reaction, methanol was injected to stop the reaction. Further, a catalyst component to which a methanol-hydrochloric acid mixture was added was decomposed, and then methanol washing was repeated three times. The yield of the styrene-1,3-butadiene copolymer obtained here was 41.4 g. The intrinsic viscosity measured at 135 ° C. in a 1,2,4-trichlorobenzene solution was 1.63 dl / g.

It is proved from the results of a differential scanning calorimeter (DSC) and a nuclear magnetic resonance spectrum (NMR) that the styrene chain part of the styrene-1,3-butadiene copolymer has a syndiotactic structure.

(A) Measurement by DSC After sufficiently drying the styrenic copolymer obtained in Example 1, 10 mg was put in a sample for DSC, and 50 to 300 ° C.
After the temperature was increased at a rate of 20 ° C./min, the temperature was maintained at 300 ° C. for 5 minutes, and the temperature was lowered from 300 ° C. to 50 ° C. at a rate of 20 ° C./min. The heat absorption and exothermic pattern when this sample was heated again from 50 ° C. to 300 ° C. at a rate of 20 ° C./min was observed. The apparatus used was DSC-II manufactured by PerkinElmer.

As a result, the copolymer had a glass transition temperature (Tg) of 82.
° C and melting temperature (Tm) 269 ° C.

Conventional atactic polystyrene has no melting temperature, and isotactic polystyrene has a melting temperature of 23.
0 ° C., and the melting temperature of the copolymer does not become higher than the higher one of the melting temperatures of the respective homopolymers.
From these facts, it can be seen that the styrene chain portion of this copolymer has a syndiotactic structure, and that the copolymer is crystalline.

(B) Measurement by ¹³ C-NMR As a result of measuring the styrene-based copolymer in a 1,2,4-trichlorobenzene solution at 135 ° C., the aromatic signal was 145.1.
ppm and 145.9 ppm. This confirmed that the styrene chain had a syndiotactic structure. Further, peaks derived from a butadiene chain were observed at 22.3 ppm and 27.5 ppm. The content of the 1,3-butadiene chain in the copolymer was 8.0% by weight. The used apparatus was FX-200 manufactured by JEOL Ltd.

(C) Morphology of molded article This copolymer was injection molded at a melting temperature of 300 ° C and a mold temperature of 100 ° C. Observation of the cross section of this injection-molded product showed a very good dispersion state that could not be observed with a normal incompatible mixture, and only fine domains were dispersed. The Izod impact value of this molded product was measured according to JIS-K7110.

Table 1 shows the obtained results. Further, when the gloss was visually confirmed, it was found that the gloss of the molded article was improved by copolymerization.

From the above results, it was found that this copolymer was a crystalline styrene-butadiene copolymer containing a styrene chain having a syndiotactic structure. In addition, it was found that the moldability was improved by lowering the Tg, the impact was improved by imparting flexibility, and the gloss was also improved.

Examples 2 to 4 and Comparative Examples 1 to 3 A styrene-butadiene copolymer or a styrene-isoprene copolymer was prepared in the same manner as in Example 1 using the raw materials, catalysts, and polymerization conditions shown in Table 1 below. Obtained. Table 1 shows the properties of the obtained copolymer together with the results of Example 1.

a) pentamethylcyclopentadienyltitanium trimethoxide b) cyclopentadienyltitanium trichloride c) methylaluminoxane d) measured in 1,2,4-trichlorobenzene at 135 ° C. e) visual judgment ◎ very good ○ Good △ Poor [Effect of the Invention] The styrenic copolymer of the present invention has the heat resistance and chemical resistance of syndiotactic polystyrene, but has a low glass transition temperature, so that low-temperature injection molding becomes possible, and gloss is obtained. And flexibility has been greatly improved.

Therefore, the styrenic copolymer of the present invention is useful as various structural materials and compatibilizers. Such a copolymer can be efficiently produced by the method of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C08F 4/64-4/70 C08F 12/06-12/12 C08F 212/06-212/12 C08F 36 / 04-36/08 C08F 236/04-236/08

Claims (3)

(57) [Claims] 1. A compound of the formula [I] [Wherein R ¹ is a hydrogen atom, a halogen atom or
Or less hydrocarbon groups, and m represents an integer of 1 to 3.
When m is plural, each R ¹ may be the same or different. ] And a diene-based repeating unit [II] represented by the formula: wherein the diene-based repeating unit [I
I] of 0.1 to 50% by weight and 1,2,4-
Intrinsic viscosity measured in trichlorobenzene is 0.07-20dl
/ g, and the stereoregularity of the styrene repeating unit [I] chain is mainly a syndiotactic structure. 2. A compound of the general formula [I '] Wherein R ¹ and m are the same as above. A styrene monomer and a diene monomer represented by the general formula TiRXYZ wherein R represents a cyclopentadienyl group, a substituted cyclopentadienyl group or an indenyl group, and X, Y and Z each independently represent hydrogen. Atom, alkyl group having 1 to 12 carbon atoms, alkoxy group having 1 to 12 carbon atoms, aryl group having 6 to 20 carbon atoms, aryloxy group having 6 to 20 carbon atoms, arylalkyl group having 6 to 20 carbon atoms or halogen Indicates an atom. The method for producing a styrenic copolymer according to claim 1, wherein the copolymerization is carried out in the presence of a catalyst comprising a titanium compound represented by the formula (1) and an alkylaluminoxane. 3. The method according to claim 1, wherein the alkylaluminoxane is formed of an aluminum-methyl group (Al
The high magnetic field component (−0.1 to −0.5 ppm based on 2.35 ppm of the methyl proton of toluene under the measurement conditions of the toluene solvent) in the methyl proton signal region based on the —CH ₃ ) bond is 50.
3. The method for producing a styrenic copolymer according to claim 2, wherein the amount of methylaluminoxane is not more than 5%.