JP2744282B2 - Styrene copolymer and method for producing the same - Google Patents

Description

The present invention relates to a styrenic copolymer and a method for producing the same, and more particularly, to a styrenic monomer and maleimide or N-substituted maleimide (hereinafter simply referred to as "N-substituted maleimide"). The present invention relates to a copolymer having a specific three-dimensional structure consisting of a monomer of the formula (1) 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 62
JP-A-104818, JP-A-63-241009). These syndiotactic polymers or copolymers are excellent in heat resistance, chemical resistance and electrical properties, and are 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 ℃, and the heat distortion temperature under low load is high level near the melting point, but the heat distortion temperature under high load is near the glass transition temperature, which is almost different from that of conventional general-purpose polystyrene (GPPS) There is no. Further, the syndiotactic polystyrene has a decomposition onset temperature of around 320 ° C., and in this respect, there is no significant difference from ordinary GPPS.

In addition, to improve the properties of styrenic polymers with syndiotactic structure, we proposed to compound them with other thermoplastic resins, inorganic fillers, etc., but still improved the adhesiveness and compatibility of their interfaces. Room was left.

Therefore, the present inventors, while maintaining the heat resistance and chemical resistance of syndiotactic polystyrene, improve the glass transition temperature, that is, the heat deformation temperature under high load,
To improve the heat resistance by raising the thermal decomposition temperature, and to develop a copolymer having improved compatibility with other resins and inorganic fillers, good adhesion and improved wettability, and an efficient production method thereof. , Earnestly studied.

[Means for solving the problem]

As a result, when a styrene monomer and an N-substituted maleimide monomer are copolymerized in the presence of a specific catalyst, a copolymer having a structure in which an N-substituted maleimide component is copolymerized with a styrene-based repeating unit chain having a syndiotactic structure is obtained. The copolymer is excellent in heat resistance, chemical resistance, etc., has a high thermal deformation temperature under high load, a high thermal decomposition temperature, and shows good wettability. It was found that quality could be achieved. 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] [Wherein R ² is a hydrogen atom, a saturated hydrocarbon group having 20 or less carbon atoms, a saturated hydrocarbon group having 20 or less carbon atoms having at least one hydroxyl group, a benzyl group, a substituted benzyl group, a phenyl group or a substituted phenyl group; Represents a group. Comprising an N-substituted maleimide repeating unit represented by the formula:
It contains 0.1 to 50% by weight of the N-substituted maleimide repeating unit, has an intrinsic viscosity of 0.07 to 20 dl / g measured in 1,2,4-trichlorobenzene at 135 ° C., and has a styrene-based repeating unit chain. A styrenic copolymer characterized in that its stereoregularity is mainly a syndiotactic structure, and a compound represented by 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. ] The N-substituted maleimide monomer represented by this is copolymerized in presence of a catalyst which consists of a titanium compound and an alkylaluminoxane, The manufacturing method of the said styrene-type copolymer characterized by the above-mentioned.

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 unit: p-methylstyrene unit; m-methylstyrene unit; o-methylstyrene unit; 2,4-dimethylstyrene unit; 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 N-substituted maleimide monomer represented by the general formula [II ']. Specific examples of the N-substituted maleimide monomer include maleimide, N-methylmaleimide, N-ethylmaleimide, N-tert-butylmaleimide, N-
Phenylmaleimide and the like.

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 effects of the present invention such as improvement of the glass transition temperature, heat deformation temperature and thermal decomposition temperature cannot be sufficiently achieved. On the other hand, if it exceeds 50% by weight, crystallization is inhibited, the chemical resistance characteristic of the styrene-based polymer having a syndiotactic structure is impaired, and the polymer becomes brittle. Defects in physical properties appear.

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, α-olefins, unsaturated carboxylic esters, acrylonitrile, 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 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 [1 '] and an N-substituted maleimide monomer represented by the general formula [II']. The styrenic monomer and the N-substituted maleimide monomer are copolymerized to form repeating units [I] and [II], respectively.
Is configured. Accordingly, specific examples of the styrene monomer and the N-substituted maleimide 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 styrenic monomers and N-substituted maleimide 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 here is as described in detail in JP-A-63-241009. First, although there are various titanium compounds as the component (A), 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, an alkyl group having 1 to 20 carbon atoms, An alkoxy group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group, an arylalkyl group, an acyloxy group having 1 to 20 carbon atoms, a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group, or Shows halogen. a, b, c are each 0
And d and e each represent an integer of 0-3. And at least one compound selected from the group consisting of titanium compounds and titanium chelate compounds.

In the general formula (α) or (β), R ³ , R ⁴ , R ⁵ and
R ⁶ is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms (specifically, methyl, ethyl, propyl, butyl,
Amyl group, isoamyl group, isobutyl group, octyl group, 2
-Ethylhexyl group), an alkoxy group having 1 to 20 carbon atoms (specifically, methoxy group, ethoxy group, propoxy group, butoxy group, amyloxy group, hexyloxy group, 2
-Ethylhexyloxy group, etc.), 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) Group, benzyl group, etc.), acyloxy group having 1 to 20 carbon atoms (specifically, heptadecylcarbonyloxy group, etc.), cyclopentadienyl group, substituted cyclopentadienyl group (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. A, b, and c each represent an integer of 0 to 4, and d and e each represent an integer of 0 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 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 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. Preferably, a heat treatment is carried out at a temperature of 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 process of the present invention, the (A), are those composed mainly of component (B), in addition to further optionally other catalyst components of the, for example, the general formula AlR 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 [1 '] as a raw material, and the general formula [II] ']], Which depends on the type of the N-substituted maleimide monomer and other conditions and cannot be unambiguously determined, but is usually the ratio of aluminum in the component (B) to titanium in the component (A), that is, aluminum / as titanium (molar ratio), 1 to 10 ^6, preferably 10 to 10 ^4.

In the method of the present invention, the styrene monomer represented by the general formula [1 '] 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 N-substituted maleimide monomer to be used is copolymerized, and this copolymerization can be carried out by various methods such as bulk polymerization, solution polymerization or 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-N-phenylmaleimide copolymer 100 ml of styrene was placed in a reaction vessel having an inner volume of 0.5 l and having a stirrer.
And 6.0 mmol of the methylaluminoxane obtained in the above (1) as an aluminum atom was added.
Minutes. Then, 0.03 mmol of pentamethylcyclopentadienyltitanium trimethoxide as a titanium atom was added, and at the same time, 100 g of N-phenylmaleimide was dissolved in 300 ml of toluene.After sufficiently replacing with nitrogen, the solution was added and stirred. Polymerization was performed at 40 ° C for 5 hours. After completion of the reaction, methanol was injected to stop the reaction. 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-N-phenylmaleimide copolymer obtained here was 51.5%.
g. In addition, 13 in 1,2,4-trichlorobenzene solution
The intrinsic viscosity measured at 5 ° C. was 0.66 dl / g.

The differential scanning calorimeter (DSC) and nuclear magnetic resonance spectrum (NMR) show that the styrene chain part of this styrene-N-phenylmaleimide copolymer has a syndiotactic structure.
Prove from the results.

(A) Measurement by DSC After sufficiently drying the styrenic copolymer obtained in Example 1, 10 mg was put into a DSC sample container, and 50 ° C 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 equipment used was
It was DSC-II manufactured by PerkinElmer.

As a result, this copolymer had a glass transition temperature (Tg) of 115.
° C and melting temperature (Tm) 270 ° C.

Conventional atactic polystyrene has no melting temperature, and isotactic polystyrene has a melting temperature of 23.
At 0 ° C., the melting temperature of the copolymer will not be 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. Also, peaks derived from the N-phenylmaleimide chain were observed at 175.0 ppm and 176.5 ppm. The content of N-phenylmaleimide chains in the copolymer was 8.0% by weight. The used apparatus is FX-200 manufactured by JEOL Ltd.

(C) Measurement of heat distortion temperature (HDT) The styrene-based copolymer was pelletized at a cylinder temperature of 300 ° C using a twin-screw kneader. The obtained pellet was injection molded at a cylinder temperature of 300 ° C. to obtain a test piece. This test piece was heat-treated at 230 ° C. for 10 minutes. After that, JIS-K7
According to the measurement according to 207, HDT was 18.5 kg / cm ² at 11
9 ° C. and 235 ° C. at 4.6 kg / cm ² .

The HDT of syndiotactic polystyrene was found to be about 100 ° C., indicating that this was improved by copolymerization.

(C) Thermal decomposability Thermogravimetric analysis was performed to evaluate the thermal decomposability of the obtained copolymer. A 10 mg sample was placed in the measurement sample holder, and the temperature was increased at a rate of 20 ° C./min under a nitrogen atmosphere. The apparatus used was SSC / 560GH manufactured by Daini Seiko.
The decomposition start temperature (Td) of the copolymer obtained as a result of the measurement was 36.
It was 0 ° C.

From the above results, this copolymer is a crystalline styrene-N-phenylmaleimide copolymer containing a styrene chain having a syndiotactic structure, and a high load due to an increase in Tg.
The HDT was improved, and the value of (Td-Tm) became larger than that of the conventional syndiotactic polystyrene due to the improvement of Td. This means that the temperature setting range during molding has been broadened, and the moldability has been improved.

Comparative Examples 1 to 3 and Example 2 The same operation as in Example 1 was performed using the starting materials, catalysts and polymerization conditions shown in Table 1 below to obtain a styrene-phenylmaleimide copolymer. The properties of the obtained copolymer were determined in Example 1.
The results are shown in Table 1 below.

Example 3 To a reaction vessel equipped with a stirrer having an internal volume of 0.5 l, 30 ml of styrene and 5.0 mmol of the methylaluminoxane obtained in Example 1 (1) as aluminum atoms were added, and a polymerization temperature of 50 ml was added.
Stirred at C for 30 minutes. Next, with pentamethylcyclopentadienyl titanium trimethoxide as a titanium atom, 0.1.
05 mmol was added, and 8 minutes later, 20 ml of a toluene solution containing 1.1 g of N- (2-methylphenyl) -maleimide was 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 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-N-phenylmaleimide copolymer obtained here is:
2.4 g. The intrinsic viscosity measured at 135 ° C. in a 1,2,4-trichlorobenzene solution was 6.88 dl / g. The results are shown in Table 2.

Next, the obtained copolymer was subjected to Soxhlet extraction for 8 hours using methylene chloride, and was sufficiently dried. The extraction rate was 15.0%. In the infrared absorption spectrum of the copolymer remaining after extraction, absorption due to the carbonyl group of N- (2-methylphenyl) -maleimide was observed at around 1704 cm ^-1 . Further, in the measurement of ¹³ C-NMR, 145.1 and 1
An aromatic signal was observed at 45.0 ppm, confirming that the styrene chain had a syndiotactic structure.

Example 4 In the same manner as in Example 3 except that p-methylstyrene was used instead of styrene and N-phenylmaleimide was used instead of N- (2-methylphenyl) -maleimide. went. The results are shown in Table 2.

a) Pentamethylcyclopentadienyltitanium trimethoxide b) Tetraethoxytitanium c) Azoisobutyronitrile d) Methylaluminoxane e) Measured at 135 ° C. in 1,2,4-trichlorobenzene [Effect of the Invention] The present invention Styrene-based copolymers have the heat resistance and chemical resistance of syndiotactic polystyrene, but have increased glass transition temperature, heat deformation temperature, and thermal decomposition temperature,
Adhesion and wettability are significantly 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.

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] [Wherein R ² is a hydrogen atom, a saturated hydrocarbon group having 20 or less carbon atoms, a saturated hydrocarbon group having 20 or less carbon atoms having at least one hydroxyl group, a benzyl group, a substituted benzyl group, a phenyl group or a substituted phenyl group; Represents a group. And 0.1 to 50% by weight of the maleimide or N-substituted maleimide repeating unit.
A styrene-based material having an intrinsic viscosity of 0.07 to 20 dl / g measured in 1,2,4-trichlorobenzene at ℃ and a stereoregularity of a styrene-based repeating unit chain mainly having a syndiotactic structure. Copolymer. 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. A maleimide or an N-substituted maleimide monomer represented by the general formula Ti RXYZ 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, 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 Indicates 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%.