JP2746409B2 - Styrene copolymer and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a styrene-based copolymer and a method for producing the same, and more specifically, a copolymer having a specific stereostructure composed of a styrene-based monomer and an acrylonitrile-based monomer, and It relates to the efficient manufacturing method.

[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 has excellent chemical resistance and electrical properties, and is expected to be used in various fields.

However, the above polymers, especially syndiotactic polystyrene, were comparable in impact resistance to conventional atactic polystyrene. Therefore, it has been proposed to improve the impact resistance by adding other thermoplastic resins, rubbers, inorganic fillers and the like, but there is still room for improvement.

The present inventors have developed a copolymer having improved impact resistance while maintaining the heat resistance and chemical resistance of syndiotactic polystyrene, a copolymer having an adhesive property suitable for compounding for further improvement, and a copolymer thereof. In order to develop efficient manufacturing methods,
We continued our research.

[Means for solving the problem]

As a result, when a styrene-based monomer and an acrylonitrile-based monomer are copolymerized in the presence of a specific catalyst, a copolymer having a structure in which an acrylonitrile-based component is copolymerized with a styrene-based repeating unit chain having a syndiotactic structure is generated. It has been found that this copolymer has excellent heat resistance, chemical resistance, impact resistance and the like, and can achieve the desired modification. 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 represented by the general formula [II] [In the formula, R ² represents a hydrogen atom or a methyl group. The acrylonitrile-based repeating unit represented by the formula (1), containing 0.1 to 50% by weight of the acrylonitrile-based repeating unit and having an intrinsic viscosity of 0.07 to 20 dl / g measured in 1,2,4-trichlorobenzene at 135 ° C. A styrenic copolymer characterized by having a styrene-based repeating unit chain having a stereoregularity mainly in a syndiotactic structure; Wherein R ¹ and m are the same as above. A styrene monomer represented by the general formula [II ']: Wherein R ² is the same as described above. ] The acrylonitrile-based monomer represented by the formula is copolymerized in the presence of a catalyst comprising a titanium compound and an alkylaluminoxane.

The styrenic copolymer of the present invention comprises a repeating unit represented by the general formula [I] and a repeating unit represented by the general formula [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) or 20 or less carbon atoms, preferably 10 to 1 carbon atoms.
Hydrocarbon groups (for example, a saturated hydrocarbon group (especially an alkyl group) such as a methyl group, an ethyl group, a propyl group, 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 represented by the general formula (I) include styrene units; p-methylstyrene units; m-methylstyrene units; o-methylstyrene units; 2,4-dimethylstyrene units; 2,5- Dimethylstyrene unit; 3,4-dimethylstyrene unit; 3,5-dimethylstyrene unit; p-ethylstyrene unit; m-ethylstyrene unit; alkylstyrene unit 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 units; p-fluorostyrene units; m-fluorostyrene units; o-fluorostyrene units; halogenated styrene units such as o-methyl-p-fluorostyrene units, or a mixture of two or more of these. Can be

On the other hand, the repeating unit represented by the general formula [II] is derived from an acrylonitrile-based monomer represented by the general formula [II ']. Specific examples of the acrylonitrile-based monomer include acrylonitrile and methacrylonitrile.

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. When the content of the repeating unit [II] is less than 0.1% by weight, the effects of the present invention, such as imparting flexibility, cannot be sufficiently achieved. On the other hand, if it exceeds 50% by weight, crystallization is inhibited, the chemical resistance characteristic of styrenic polymers having a syndiotactic structure is impaired, and coloring (burning) tends to occur during molding. Defects in physical properties similar to those of the system polymer are exhibited.

The molecular weight of this copolymer is generally 0.07 as measured by a 1,2,4-trichlorobenzene solution (at a temperature of 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]. Such compounds include, for example, dienes,
Examples include vinyl siloxanes, unsaturated carboxylic esters, and olefins.

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 syndiotacticity slightly varies 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 represented by the general formula [I '] and an acrylonitrile monomer represented by the general formula [II']. The styrene monomer and the acrylonitrile monomer are copolymerized to form repeating units [I] and [II], respectively.
Is configured. Therefore, specific examples of the styrene-based monomer and acrylonitrile-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 acrylonitrile-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 ³ _a R ⁴ _b R ⁵ _c R ⁶ _{4- (a + b + c)} (α) or TiR ³ _d R ⁴ _e R ⁵ _{3- (d + e)} …… (β) [wherein R ³ , R ⁴ , R ⁵ and R ⁶ are each hydrogen and carbon number 1
Alkyl group having 20 to 20 carbon atoms, alkoxy group having 1 to 20 carbon atoms, aryl group having 6 to 20 carbon atoms, alkylaryl group, arylalkyl group, acyloxy group having 1 to 20 carbon atoms, cyclopentadienyl group, substituted cyclopentane It represents a dienyl group, an indenyl group or a halogen. a, b, c are each 0
4 represents an integer, 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 ³ , R ⁴ , R ⁵ and R ^{6 in the} general formula (α) or (β)
Each represents a hydrogen atom or 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, a methoxy group, an ethoxy group, a propoxy group,
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 ³ , R ⁴ , R ⁵ and R ⁶ 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, and X, Y and Z each independently represent a hydrogen atom, Represents 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. . ] 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 at least one alkyl group, for example, an ethylcyclopentadienyl 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 cyclopentadienyltrimethylmethane, cyclopentadienyltriethyltitanium, cyclopentadienyltripropyltitanium, cyclopentadienyltributyltitanium, methylcyclo Pentadienyltrimethyltitanium, 1,2-dimethylcyclopentadienyltrimethyltitanium, pentamethylcyclopentadienyltrimethyltitanium, pentamethylcyclopentadienyltriethyltitanium, pentamethylcyclopentadienyltripropyltitanium, pentamethylcyclopenta Dienyl tributyl titanium, cyclopentadienyl methyl titanium dichloride, cyclopentadienyl ethyl titanium dichloride, pentamethyl dichloropentadienyl methyl titanium 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 as the component (B) used together with the above 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 ⁷ 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, the contact product of an alkylaluminoxane such as a trialkylaluminum with water is a mixture of unreacted trialkylaluminum and various condensation products together with the above-described chain alkylaluminoxane and cyclic alkylaluminoxane, and furthermore, these are complex. 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 the high magnetic field component (ie, −0.1 to −0.5 ppm) and the other magnetic field components (that is, 1.0 to −0.5 ppm) were measured. 0.1 ppm), the high magnetic field component is 50% or less of the whole, preferably 45 to 5%.
% 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 components (A) and (B) as main components. In addition to the above, other catalyst components, for example, a general formula AlB ⁸ ₃ [wherein R ⁸ 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, the styrene monomer represented by the general formula [I '] as a raw material, and the general formula [II ']], Which depends on the type of the acrylonitrile-based monomer 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 to 10 ⁴ .

In the method of the present invention, the styrene monomer represented by the general formula [I '] and the styrene monomer represented by the general formula [II'] are used in the presence of a catalyst containing the above components (A) and (B) as main components. The acrylonitrile-based monomer is copolymerized, and this copolymerization can be performed 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 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 copper sulfate 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-acrylonitrile copolymer 120 ml of styrene and 10.0 mmol of methylaluminoxane obtained in the above (1) were added as aluminum atoms to a reaction vessel having an inner volume of 0.5 and equipped with a stirrer.
For a minute. Then, 0.05 mmol of pentamethylcyclopentadienyltitanium trimethoxide as a titanium atom was added, and 80 ml of acrylonitrile was further added. Thereafter, polymerization was carried out at 70 ° C. for 4 hours with stirring. After the reaction,
The reaction was stopped by injecting methol. Further, a methanol-hydrochloric acid mixture was added to decompose the catalyst component, and then washing with methanol was repeated three times. The yield of the styrene-acrylonitrile copolymer obtained here was 12.5 g. The intrinsic viscosity measured at 135 ° C. in a 1,2,4-trichlorobenzene solution was 1.48 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 portion of the styrene-acrylonitrile 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 raised 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 is DSC-II manufactured by PerkinElmer.

As a result, the copolymer had a glass transition temperature of 102 ° C and a melting temperature of 268 ° C.

Conventional atactic polystyrene has no melting temperature, and isotactic polystyrene has a melting temperature of 23.
0 ° C., the melting temperature of the copolymer will not be higher than the higher melting temperature of each homopolymer,
The styrene chain part of this copolymer has a syndiotactic structure, which indicates that the copolymer is crystalline.

(B) Measurement of infrared spectrum The styrene-based copolymer obtained in Example 1 was press-formed at a heater temperature of 300 ° C. using a mini press manufactured by Toyo Seiki Co., Ltd., and tested for 10 × 20 mm and 1.5 mm thickness. I got a piece. When this test piece was measured with an A-202 infrared spectrometer manufactured by JASCO Corporation, the characteristic absorption of the cyano group was found at 2250 cm ^-1 and 1603 cm ^-1.
And a peak at 1225 cm ^-1 based on crystalline polyolefin.

(C) Measurement by ¹³ C-NMR As a result of measuring the styrenic copolymer in a 1,2,4-trichlorobenzene solution at 135 ° C., the aromatic signal was 145.1.
ppm, 145.9 ppm. This confirmed that the styrene chain had a syndiotactic structure. The acrylonitrile chain content in the copolymer was 7.0% by weight. The equipment used was manufactured by JEOL Ltd.
FX-200.

(D) Measurement of Elongation The styrene copolymer was pelletized at a cylinder temperature of 300 ° C. using a twin-screw kneader. Using the obtained pellets, injection molding was performed at a cylinder temperature of 300 ° C. to obtain a test piece. The elongation of this test piece was 4.1% when measured according to JIS-K7113.

(E) Measurement of critical surface tension The styrene copolymer was melted at 300 ° C to prepare a press sheet. When the critical surface tension of this sheet was measured by a droplet shape method using ethyl benzoate / ethylene glycol / formalin / water, it was 37 dyne / cm, which was higher than that of syndiotactic polystyrene of 33 dyne / cm. Generally, the critical surface tension is regarded as an index of the adhesiveness of the resin, and it has been found that this copolymer has improved adhesiveness and compatibility.

From the above results, it was found that this copolymer was a crystalline styrene-acrylonitrile copolymer containing a styrene chain having a syndiotactic structure.

Comparative Examples 1 to 3 and Example 2 The same operation as in Example 1 was performed using the raw materials, catalysts and polymerization conditions shown in Table 1 below to obtain a styrene-acrylonitrile copolymer. Table 1 shows the properties of the obtained copolymer together with the results of Example 1.

Example 3 (a) Production of p-methylstyrene-acrylonitrile copolymer 30 ml of p-methylstyrene and a methylaluminoxane obtained in Example 1 (1) were placed in a reaction vessel having an inner volume of 0.5 and having a stirrer as aluminum atoms. 5.0 mmol was added, and the mixture was stirred at a polymerization temperature of 50 ° C. for 30 minutes. Next, 0.05 mmol of pentamethylcyclopentadienyltitanium trimethoxide as a titanium atom was added, and 8 minutes after the start of the reaction, 3.0 ml of acrylonitrile was further added. Thereafter, polymerization was carried out at 50 ° C. for 1 hour with stirring. After completion of the reaction, methanol was injected to stop the reaction. Further, a mixed solution of methanol and hydrochloric acid was added to decompose the catalyst component, and then washing with methanol was repeated three times.

The yield of the p-methylstyrene-acrylonitrile copolymer obtained here was 2.4 g. The intrinsic viscosity measured at 135 ° C in a 1,2,4-trichlorobenzene solution is
It was 0.57 dl / g.

(B) DSC measurement The p-methylstyrene obtained in Example 3 (a) above was used.
The acrylonitrile copolymer was measured under the same conditions as in Example 1 (2). As a result, the glass transition temperature of the copolymer was 109 ° C., but no melting peak was observed under the measurement conditions.

(C) Measurement of Infrared Spectra The p-methylstyrene-acrylonitrile copolymer was measured under the same conditions as in Example 1 (2). The characteristic absorption of the cyano group was found at 2250 cm ^-1 and the aromatic absorption at 1603 cm ^-1. A peak due to the ring was observed.

(D) Measurement by ¹³ C-NMR When the above p-methylstyrene-acrylonitrile copolymer was measured under the same conditions as in Example 1 (2), one sharp peak was observed in the range of 145.3 to 145.5 ppm. Was. From this, it was confirmed that the p-methyl chain had a syndiotactic structure. The acrylonitrile chain content in the copolymer was 3.5% by weight.

Example 4 A styrenic copolymer was obtained using the raw materials and monomers shown in Table 2 below. The copolymerization conditions were the same as in Example 3.

Example 5 A copolymerization was carried out by the same polymerization method as in Example 1 except that 50 ml of toluene was used as a solvent under the conditions shown in Table 2 below. The obtained copolymer was extracted by Soxhlet extraction in the order of methyl ethyl ketone and then dimethylformamide. In addition, about dimethylformamide, extraction was performed under reduced pressure so that a boiling point might be set to 100 degreeC. The extraction rate was 42.5%.

After the extraction residue was sufficiently dried, the same analysis as in Example 1 was performed. The results are shown in Table 2 together with the results of Examples 3 and 4.

[Effect of the Invention] The styrenic copolymer of the present invention has excellent impact resistance and flexibility while retaining heat resistance and chemical resistance of syndiotactic polystyrene. Such a copolymer can be efficiently produced by the method of the present invention.

Therefore, the styrenic copolymer of the present invention is useful as various structural materials and compatibilizers.

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. A styrene-based repeating unit represented by the general formula [II] [In the formula, R ² represents a hydrogen atom or a methyl group. An acrylonitrile-based repeating unit represented by the formula (1), containing 0.1 to 50% by weight of the acrylonitrile-based repeating unit, and having an intrinsic viscosity of 0.07 to 20 dl / g measured in 1,2,4-trichlorobenzene at 135 ° C. A styrene-based copolymer characterized in that the styrene-based repeating unit chain has a stereoregularity mainly in a syndiotactic structure. 2. A compound of the general formula [I '] Wherein R ¹ and m are the same as above. A styrene monomer represented by the general formula [II ']: Wherein R ² is the same as described above. And an acrylonitrile 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 a hydrogen atom or a carbon atom. It represents 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. 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%.