JP2761043B2 - Method for producing styrenic polymer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a styrene-based polymer, and particularly to efficiently produce a styrene-based polymer having a syndiotactic structure of 30% or more in racemic pentad. About the method.

[Problems to be solved by conventional technology and invention]

Conventionally, when styrene or a styrene derivative is polymerized to produce a styrene polymer, especially a styrene polymer having a syndiotactic structure of 30% or more in racemic pentad, (A) tetravalent or trivalent It is known to use a catalyst comprising a titanium compound and (B) a contact product of an organoaluminum and a condensing agent (JP-A-62-104818).
And JP-B-62-187708).

However, since the above-described catalyst contains a halogen, impurities derived from the halogen are likely to be mixed into the polymerization solvent, and at the same time, remain in the produced polymer,
There is a disadvantage that the polymer is deteriorated or discolored. In addition, since the transition metal compound in a high valence state and the organoaluminum are used in combination, they react with each other, and a mixture of many oxidation states is likely to be generated, and the oxidation state of the transition metal tends to be unstable. Therefore, the stability of the catalyst was lacking, and it was difficult to stably produce the polymer.

Accordingly, the present inventors have intensively studied to solve the above-mentioned drawbacks of the catalyst and to develop a catalyst which has no risk of introducing impurities into a polymerization reaction system or a produced polymer and has excellent stability and high polymerization activity. Was piled up.

[Means for solving the problem]

As a result, when styrene or a styrene derivative is polymerized using a titanium or zirconium compound having a ligand composed of a specific hydrocarbon as a component of the catalyst as a catalyst, a styrene-based polymer, in particular, ceramipentad It was found that a styrenic polymer having a syndiotactic structure of 30% or more can be efficiently produced. The present invention has been completed based on such findings.

That is, the present invention provides (a) a titanium or zirconium compound having a ligand consisting of a specific hydrocarbon,
And (b) a method for producing a styrene-based polymer, characterized in that styrene or a styrene derivative is polymerized in the presence of a catalyst whose main component is a contact product of a specific trialkylaluminum and water. is there.

The catalyst used in the method of the present invention comprises the above two components (a) and (b) as main components. Here, the titanium or zirconium compound having a ligand consisting of a specific hydrocarbon as the component (a) is represented by the general formula A ¹ A ² M [where A ¹ and A ² are cyclotriene, benzene,
Alternatively, it represents an alkylbenzene having 7 to 23 carbon atoms, and M represents titanium or zirconium. A ¹ and A ² may be the same or different. ] The compound of titanium or zirconium represented by these. Here, examples of the cyclotriene include cycloheptatriene and cyclooctatriene.

As the component (a) of the present invention, specifically, bis (benzene) titanium [(C ₆ H ₆ ) ₂ Ti], bis (toluene) titanium [(C ₆ H ₅ CH ₃ ) ₂ Ti], bis ( o-chylesin) titanium [(1,2- (CH ₃ ) ₂ C ₆ H ₄ ) ₂ Ti], bis (m-xylene) titanium [(1,3- (CH ₃ ) ₂ C ₆ H ₄ ) ₂ Ti ], Screw (p
- xylene) titanium _{[(1,4- (CH 3) 2 C} 6 H 4) 2 Ti ],
Bis (mesitylene) titanium [(1,3,5- (CH ₃ ) ₃ C ₆ H ₃ )
₂ Ti], bis (hemimeryten) titanium [(1,2,3- (C
H ₃ ) ₃ C ₆ H ₃ ) ₂ Ti], bis (pseudocumene) titanium [(1,2,4- (CH ₃ ) ₃ C ₆ H ₃ ) ₂ Ti], bis (prenitene) titanium [(1,2 , 3,4- (CH ₃ ) ₄ C ₆ H ₂ ) ₂ Ti], bis (isodulene) titanium [(1,2,3,5- (CH ₃ ) ₄ C ₆ H ₂ ) ₂ T
i], bis (pentamethylbenzene) titanium [C ₆ H (C
H ₃ ) ₅ ) ₂ Ti], bis (hexamethylbenzene) titanium
(C ₆ (CH ₃ ) ₆ ) Ti, and further bis (cycloheptatriene)
Titanium, bis (cycloheptatriene) zirconium, bis (cyclooctatriene) titanium, bis (cyclooctatriene) zirconium and the like can be mentioned.

Although there are various methods for synthesizing the component (a) of the present invention, for example, “MTAnthony, MLHGreen, D. Young;
J. Chem. Soc., Dalton Trans., 1975, 1419 ".

On the other hand, the other component of the catalyst used in the method of the present invention, (b) a contact product of a specific trialkylaluminum and water is the same as that described in JP-A-62-187708. is there. Details are as follows.

Here, the specific trialkylaluminum, that is, the trialkylaluminum of the present invention is represented by the general formula: AlR ₃ [wherein, R represents an alkyl group having 1 to 8 carbon atoms. And specific examples thereof include trimethylaluminum, triethylaluminum, and triisobutylaluminum, among which trimethylaluminum is most preferred.

The contact product of the trialkylaluminum of the present invention, which is the component (b), and water is specifically represented by a general formula: [In the formula, n represents 0 to 50, and R is the same as described above. Or a linear alkylaminoxan represented by the general formula [Wherein, R is the same as described above. And a cyclic alkylaluminoxane having a repeating unit represented by the formula (2 to 50 repeating units).

In general, the contact product of the trialkylaluminum and water of the present invention is, together with the above-mentioned chain alkylaluminoxane and cyclic alkylaluminoxane, an unreacted trialkylaluminum, a mixture of various condensation products, and furthermore, these are complex. These are associated molecules, which can be various products depending on the contact conditions between the trialkylaluminum and water.

At this time, the reaction between the trialkylaluminum of the present invention and water is not particularly limited, and may be performed according to a known method. For example, a method of dissolving the trialkylaluminum of the present invention in an organic solvent and bringing it into contact with water, a method of initially adding the trialkylaluminum of the present invention during polymerization, and then adding water, and further a metal salt For example, there is a method of reacting the water of crystallization and the water adsorbed on an inorganic substance or an organic substance with the trialkylaluminum of the present invention. This reaction proceeds in the absence of a solvent, but is preferably carried out in a solvent. Suitable solvents include aliphatic hydrocarbons such as hexane, heptane and decane and aromatic hydrocarbons such as benzene, toluene and xylene. Can be given.

The catalyst used in the method of the present invention includes the above (a) and (b)
And mainly composed of components, other further optionally other catalyst components of the, for example, the general formula AlR ¹ ₃ wherein, R ¹ represents an alkyl group having 1 to 8 carbon atoms. ], Or other organometallic compounds represented by the formula:

In using this catalyst, the ratio of the component (a) to the component (b) in the catalyst varies depending on the type of each component, the type of the monomer to be polymerized, and other conditions, and cannot be unambiguously determined. ⁶ to 10 as (b) the ratio of aluminum and (a) a transition metal in the component in the component (titanium or zirconium), i.e. aluminum / transition metal (mole ratio), preferably 10 to 10 ^4.

The method of the present invention involves polymerizing styrene or a styrene derivative in the presence of the above catalyst. Here, styrene derivatives include methylstyrene, ethylstyrene,
Alkylstyrenes such as butylstyrene, p-tert-butylstyrene, and dimethylstyrene; halogenated styrenes such as chlorostyrene, bromostyrene and fluorostyrene; halogen-substituted alkylstyrenes such as chloromethylstyrene; alkoxystyrenes such as methoxystyrene; Examples thereof include carboxymethyl styrene, alkyl ether styrene, alkyl silyl styrene, vinyl benzene sulfonic acid ester, and vinyl benzyl dialkoxy phosphide.

In the method of the present invention, the above-mentioned styrene or styrene derivative is used as a raw material, but these can be polymerized alone or in combination of two or more.

The polymerization reaction in the method of the present invention may be bulk polymerization, or may be an aliphatic hydrocarbon such as pentane, hexane or heptane; an alicyclic hydrocarbon such as cyclohexane; or an aromatic hydrocarbon solvent such as benzene, toluene or xylene. Alternatively, the reaction may be performed in a mixed solvent thereof.

Further, the polymerization temperature is not particularly limited, but is generally -30.
120120 ° C., preferably -10-100 ° C.

The styrenic polymer thus obtained has a syndiotactic structure of 30% or more in racemic pentad. Here, a syndiotactic structure of 30% or more of racemic pentad in a styrene-based polymer means that a stereochemical structure is mainly a syndiotactic structure,
That is, it means that a phenyl group or a substituted phenyl group which is a side chain with respect to a main chain formed from a carbon-carbon bond has a three-dimensional structure in which the phenyl group and the substituted phenyl group are alternately located in opposite directions, and the tacticity of the nucleus is determined by the nucleus of isotope carbon. Magnetic resonance method ( ^13C -NMR method)
Quantified by Tacticity measured by the ¹³ C-NMR method is the existence ratio of a plurality of continuous structural units,
For example, two can be indicated by a dyad, three can be indicated by a triad, and five can be indicated by a pentad. According to the present invention, "a racemic pentad has a styrene-based polymer having a syndiotactic structure of 30% or more.""Coalescing"
It is a styrene polymer having a syndiotacticity of 75% or more in dyad, and in this case, a polymer having 50% or more in racemic pentad or 85% or more in dyad is particularly preferable. In addition,
The styrene-based polymer of the present invention having a syndiotactic structure of 30% or more in racemic tat refers to polystyrene, poly (alkylstyrene), poly (halogenated styrene) having a syndiotacticity of 30% or more in racemic pentad. , Poly (alkoxystyrene), poly (vinyl benzoate) and a mixture thereof, or a copolymer containing these as a main component, where poly (alkylstyrene) is poly (methylstyrene), There are poly (ethyl styrene), poly (isopropyl styrene), poly (tertiary butyl styrene), etc., and poly (halogenated styrene) includes poly (chlorostyrene), poly (bromostyrene), poly (fluorostyrene), etc. The poly (alkoxystyrene) includes poly (Methoxystyrene), poly (ethoxystyrene), etc. Among these, particularly preferred styrene polymers are polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), poly (p-tertiary). Butylstyrene), poly (p-chlorostyrene), poly (m-chlorostyrene), poly (p
-Fluorostyrene), and a copolymer of styrene and p-methylstyrene.

Styrenic polymer produced by the method of the present invention,
Generally a weight average molecular weight of 5,000 or more, preferably 10,000 to
2,000,000, number average molecular weight 2,500 or more, preferably 5,000
~ 1,000,000 and high syndioctacycity as described above, but after polymerization, if necessary, deashed with a washing solution containing hydrochloric acid, etc., and further washed, dried under reduced pressure, and then washed with methyl ethyl ketone, etc. If the soluble matter is removed by washing with a solvent and the resulting insoluble matter is further treated with chloroform or the like, a highly pure styrene-based polymer 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) Preparation of (a) component (titanium compound) 800 mg of titanium metal (manufactured by Alfa Products Ltd., purity 99.6%, rod shape of 12.5 mm radius) was reduced under reduced pressure (about 5 × 10 ^-5 tor).
Under r), the mixture was vaporized at 1,750 ° C. for 2 hours and condensed with 90 cc of benzene (dehydrated with calcium hydride and distilled) onto the reactor wall cooled to 77 ° K with liquid nitrogen with liquid nitrogen. As a result, a condensate was obtained in a yield of about 1 g.

The obtained compound (condensate) elemental analysis values shown below, it was confirmed by proton nuclear magnetic resonance from ⁽¹ H-NMR) spectra and mass spectra bis (benzene) titanium.

Elemental analysis ^{Ti 24.1wt%, 1 H-NMR} 4.96ppm ( tetramethylsilane criteria) 4.87Ppm (tetramethylsilane criteria) Mass spectrum 204 [(H ₁₂ C ₁₂₎ ⁴⁸ Ti] ⁺ 126 [(H ₆ C ₆ ) Ti] ⁺ 48 ⁴⁸ Ti ⁺ The details of the apparatus, reaction conditions, and compounds obtained here are described in JCS Dalton Trans., 1975, 1419.

(2) (b) during the preparation reaction vessel component (aluminoxane), placed toluene 200 ml, further trimethylaluminum 47.4 ml (492 mmol) and copper sulfate pentahydrate _{(CuSO 4 · 5H 2 O)} 35.5g (142 mmol ) Was added and reacted at 20 ° C. for 24 hours under a stream of argon.

Copper sulfate was filtered off from the obtained reaction solution, and toluene was distilled off to obtain 12.4 g of methylaluminoxane.
The thus obtained methylaluminoxane had a molecular weight of 721 as measured by the freezing point depression method of benzene.

(3) Polymerization of styrene In a 100 ml internal volume reaction vessel, 10 ml of toluene, (1) above
0.025 mmol of bis (benzene) titanium obtained in the above and 15 mmol of methylaluminoxane obtained in the above (2) were added as aluminum atoms, and 50 ml of styrene was introduced into this reaction vessel at 50 ° C. to carry out a polymerization reaction for 4 hours. .

After completion of the reaction, the product was washed with a mixed solution of hydrochloric acid and methanol to remove the catalyst component by decomposition and dried to obtain 2.5 g of a polymer.

Next, the obtained polymer was subjected to Soxhlet extraction using methyl ethyl ketone as a solvent, and an extraction residue (MIP) of 95.9 w
t% was obtained. The weight average molecular weight (Mw) of the obtained polymer (MIP) was 177,000, the number average molecular weight was 79,800 (Mn), and the molecular weight distribution (Mw / Mn) was 2.21.

Further, based on the C ₁ carbon signal of the aromatic ring (phenyl group in polystyrene) by ¹³ C-NMR of this polymer, this polymer has a high syndiotacticity with a syndiooctacity of 90% or more in racemic pentad. It was found to be polystyrene with a tick structure. The results are shown in Table 1.
FIG. 1 shows the ¹³ C-NMR spectrum.

Examples 2 to 5 Polymerization of styrene was carried out in the same manner as in Example 1 (3) except that the catalyst and the polymerization conditions were changed as shown in Table 1. The results are shown in Table 1.

In each of the obtained polymers, the syndiotacticity of racemic pentad was 90% in the same manner as in Example 1.
It was found that the polystyrene had a high syndiotactic structure.

¹³ C-NMR spectra of the polymers obtained in Examples 2 to 5 are shown in FIGS.

[Effects of the Invention] As described above, the catalyst used in the method of the present invention is characterized in that the compound of component (a) titanium or zirconium does not contain halogen, sulfur, phosphorus, etc. Therefore, there is no contamination of the polymerization reaction system. Therefore, the treatment when the polymerization solvent is repeatedly used becomes easy, which is extremely advantageous in practical use. In addition, since the obtained polymer has no risk of contamination with impurities, problems such as deterioration, discoloration and odor hardly occur. Further, since the compound of titanium or zirconium is a compound having a valence of 0, the valence is not further reduced by a reducing agent such as trialkylaluminum, so that the compound is stable, and a polymer can be stably produced. .

Further, according to the method of the present invention, a styrenic polymer,
In particular, a styrenic polymer having high syndiotacticity can be efficiently produced. The styrene-based polymer having a syndiotactic structure thus obtained has excellent physical properties such as heat resistance and chemical resistance.

Therefore, the present invention is expected to be used effectively and widely in the field of polymer chemistry.

[Brief description of the drawings]

1 to 5 show ¹³ C-NMR spectra of the polymers obtained in Examples 1 to 5, respectively.

Claims (3)

(57) [Claims] (A) a general formula A ¹ A ² M wherein A ¹ and A ² are each a cyclotriene, benzene,
Alternatively, it represents an alkylbenzene having 7 to 23 carbon atoms, and M represents titanium or zirconium. A ¹ and A ² may be the same or different. And a compound of titanium or zirconium represented by the formula: and (b) a general formula AlR _{3 wherein} R represents an alkyl group having 1 to 8 carbon atoms. ] A method for producing a styrene-based polymer, characterized by polymerizing styrene or a styrene derivative in the presence of a catalyst containing a contact product of a trialkylaluminum and water represented by the following formula as a main component. 2. The process according to claim 1, wherein the contact product of (b) the trialkylaluminum with water is aluminoxane. 3. The styrenic polymer is a racemic pentad.
2. The method according to claim 1, wherein the styrene polymer has a syndiotactic structure of 30% or more.