JPH08208713A - Production of stereoregular polystyrene - Google Patents

Abstract

PURPOSE: To obtain a process for producing a stereoregular polystyrene whereby an almost syndiotactic polymer can be continuously produced efficeintly and stably by using a reactor having a specific structure. CONSTITUTION: An almost syndiotactic styrene polymer is continuously produced from styrene or a styrene deriv. using a reactor at a polymn. temp. of 120 deg.C or lower. The reactor is installed with an inclination and has a cylinder comprising a long twin-body case installed along the outermost periphery of a pair of shafts. Each shaft has many pairs of paddles of which sides facing to each other are mated slidably. The number of revolutions of the paddles is 100rpm or higher. An example of such a reactor is a known kneader.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for producing stereoregular polystyrene, and more particularly to a method for efficiently and stably producing stereoregular polystyrene.

[0002]

2. Description of the Related Art Recently, a styrene-based polymer having a stereoregular structure mainly having a syndiotactic structure has been developed and disclosed, for example, in JP-A-62-187708. This syndiotactic styrenic polymer has various reactors proposed in its production stage, because when the conversion rate increases, the entire system solidifies and the particle size expands and adheres. There is. For example, in JP-A-2-75607 and JP-A-2-75608, the shearing force is increased by changing the shape of the stirring blade of the batch reactor.

Further, Japanese Unexamined Patent Publication (Kokai) No. 2-191609 proposes continuous polymerization using a self-cleaning reactor, but it is necessary to provide a tank reactor or the like in the latter stage in order to obtain a sufficient conversion rate. is there.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a production method capable of continuously polymerizing a styrene-based polymer having a syndiotactic structure at a high conversion rate.

[0005]

Means for Solving the Problems Accordingly, the present inventors have:
As a result of earnest studies to develop a production method capable of continuously polymerizing a styrene-based polymer having a syndiotactic structure at a high conversion rate without requiring an additional device such as a tank reactor. Has reached the present invention. That is, the present invention is a method for continuously producing a styrene polymer mainly having a syndiotactic structure from a styrene or a styrene derivative monomer using a reactor, wherein the reactor has a pair of cylinders. A long cathedral-shaped case along the outermost edge of the shaft is used, and each of the shafts has a structure of a multi-pair paddle slidably engaged with opposite side surfaces, and the reactor has a tilt angle. Installed and set the paddle rotation speed to 10
A method for producing stereoregular polystyrene, which comprises polymerizing at 0 rpm or more and at a reaction temperature of 120 ° C. or less.

The present invention will be described in detail below. The stereoregular polystyrene referred to in the present invention mainly means a styrene-based polymer having a syndiotactic structure. The syndiotactic structure is a stereochemical structure mainly having a syndiotactic structure, that is, a stereo structure in which a phenyl group or a substituted phenyl group, which is a side chain to a main chain formed from carbon-carbon bonds, is alternately located in opposite directions. It means that it has a structure, and its tacticity is quantified by a nuclear magnetic resonance method ( ¹³ C-NMR method) using isotope carbon.

The tacticity measured by this nuclear magnetic resonance method is the existence ratio of a plurality of continuous constitutional units,
For example, two can be indicated by dyads, three can be indicated by triads, and five can be indicated by pentads. The styrene-based polymer mainly having a syndiotactic structure as used in the present invention is usually a diad of 75
% Or more, more preferably 85% or more, or pentad preferably 30% or more, more preferably 50%
Polystyrene, poly (alkylstyrene), poly (halogenated styrene), poly (alkoxystyrene), poly (vinylbenzoic acid), and mixtures thereof having the above syndiotacticity, or a copolymer containing these as the main components Means

The poly (alkylstyrene) includes poly (methylstyrene), poly (ethylstyrene), poly (isopropylstyrene), poly (tertiarybutylstyrene), etc., and the poly (halogenated styrene) is , Poly (chlorostyrene), poly (bromostyrene), poly (fluorostyrene), and the like. Examples of poly (alkoxystyrene) include poly (methoxystyrene) and poly (ethoxystyrene).

Of these, polystyrene, poly (p-methylstyrene), poly (m-methylstyrene), poly (p-tertiarybutylstyrene), poly (p-chlorostyrene), poly (m) are particularly preferred. -Chlorostyrene), poly (p-fluorostyrene), and further a copolymer of styrene and p-methylstyrene.

The styrene-based polymer produced by the present invention generally has a higher molecular weight as the reaction temperature is lower, but the weight average molecular weight is preferably 5,000 or more, more preferably 10,000 to 20,000,000, and the number average molecular weight is preferably 2,500 or more. , And more preferably 5000 to 10
After the polymerization, if necessary, a deashing treatment with an acid or alkali washing liquid, and further washing and drying treatment can give a styrene-based polymer having extremely high syndiotacticity.

The styrenic polymer mainly having a syndiotactic structure as described above is prepared, for example, in an inert hydrocarbon solvent or in the absence of a solvent, in the presence of a catalyst composed of a titanium compound and an alkylaluminoxane, a styrene monomer or / Also, it can be produced by polymerizing a substituted styrene monomer. There are various titanium compounds used as the above-mentioned catalyst, but the general formula Ti is preferable.
^{R 1 aR 2 bR 3 cX 1} 4 - (a + b + c) or TiR ¹ dR ² eX ¹ 3
-(d ₊ e) [wherein R ¹ , R ² and R ³ 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, alkyl It represents an aryl group, an arylalkyl group, an acyloxy group having 1 to 20 carbon atoms, a cyclopentadienyl group, a substituted cyclopentadienyl group or an indenyl group, and X ¹ represents halogen. a, b, and c each represent an integer of 0 to 4, and d and e
Each represents an integer of 0 to 3. ] It is at least 1 type of compound selected from the group which consists of a titanium compound and a titanium chelate compound represented by these.

The titanium compound may be used in the form of a complex with an ester or ether. On the other hand, the alkylaluminoxane, which constitutes the main component of the catalyst together with the titanium compound, is obtained by contacting various organoaluminum compounds with a condensing agent.

As the organoaluminum compound, various compounds can be used, but trialkylaluminum is usually used. Examples of the trialkylaluminum include trimethylaluminum, triethylaluminum, tri-i-butylaluminum and the like. Two or more kinds of these organoaluminum compounds may be used.
Water is typically used as the condensing agent, but any condensing agent that causes an organoaluminum compound to undergo a condensation reaction may be used. The reaction between the organoaluminum compound and water is not particularly limited and may be performed according to a known method.

Typical examples of the alkylaluminoxane obtained by the reaction of an organoaluminum compound and water include chain alkylaluminoxane and cyclic alkylaluminoxane. In addition, unreacted trialkylaluminum and various condensation products There are mixtures, as well as molecules with complex associations thereof, which result in different products depending on the contact conditions of the trialkylaluminum and water.

When the alkylaluminoxane is used as a catalyst, two or more of the above various products may be used, or an organoaluminum compound may be mixed. Further, other organometallic compounds may be mixed, or the alkylaluminoxane may be adsorbed on or supported by an inorganic substance. In the present invention, the reactor is composed of a long catamaran case substantially along the outermost edges of a pair of shafts, and has a large number of pairs of paddle structures in which the shafts are slidably engaged with their opposite side surfaces. Use something.

As such a reactor, a conventionally known reactor can be used. Examples thereof include the kneaders described in US Pat. No. 3,195,865 and US Pat. No. 3,198,491. Specifically, there is a kneader such as KRC Kneader manufactured by Kurimoto Iron Works or SCR manufactured by Mitsubishi Heavy Industries, Ltd. 1 and 2 are
It shows an example of the above-mentioned reactor. This reactor 1
Rotates in the same direction in a cylinder 2 with a cross section of eyebrows 2
A parallel shaft (rotating shaft) 3 is provided, and the rotating shaft 3
A large number of convex lens type paddles 4 are attached to the.
The paddle 4 is formed so that the protruding portion 4 a scrapes the inner wall of the cylinder 2, and the other rotating shaft 3
The paddles 4 are attached so that their phases are shifted by 90 degrees from the opposing paddles 4 attached to each other, and the projecting portions 4a are arranged so as to scrape off the surface of the paddle 4 on the other side.

Further, a raw material supply port 5 is opened at the upper end of one end of the cylinder 2 and a discharge port 6 is opened at the lower end of the other end, and the temperature of the cylinder 2 is controlled around the cylinder 2. A jacket 7 is provided for this purpose. The discharge port 6 can also be opened on the other end side. The raw material supply port 5 can be opened at one end lower part of the cylinder 2, and the discharge port 6 can be opened at the other end upper part or the other end side part.

Further, by arranging the phase of the paddle group in the axial direction in a spiral shape extending from the raw material supply port 5 of the cylinder 2 to the discharge port 6 or in a combination of the spiral shape and the orthogonal shape, a polymerization product or the like is discharged. It can be delivered towards the exit 6. Furthermore, by changing the thickness of the paddle 4 in the axial direction according to the arrangement position, it is possible to perform stirring suitable for stirring liquid and stirring powder.

In addition to the above convex lens-shaped paddle 4, as shown in FIG. 3A, a stepped portion 4b is formed at the tip of the protruding portion 4a of the convex lens-shaped paddle 4 for efficient scraping. The ones that were made possible, etc.
The rice ball-shaped paddle 8 and the like shown in (b) can be appropriately used. The method for producing stereoregular polystyrene of the present invention is characterized in that the reactor is tilted and used. It is preferable that the reactor shaft is not horizontal and the inclination angle is 15 degrees or less.

The inclination angle referred to here is, as shown in FIG. 4, an angle θ formed by the horizontal plane of the pedestal for fixing the reactor and the floor on which the reactor is installed. If the horizontal plane of the pedestal of the reactor exceeds 15 degrees and the inclination of the shaft is too large, mechanical load is applied to the shaft and the motor, resulting in damage to the equipment. More preferably, it is used in the range of 2 to 10 degrees. When used in this range, the retention amount and retention time required for the present invention can be set.

Considering the simplification of the polymer recovery process, the raw material supply port is provided above the reaction tank, the discharge port for the polymerization products and the like is provided below or beside the reaction tank, and the reaction is performed with the discharge port side facing upward. It is preferred to tilt the tank and polymerize. After the reaction is completed, the discharge is facilitated by tilting the discharge port side downward. In the method for producing stereoregular polystyrene of the present invention, it is desirable that the number of rotations of the paddle is set to a high speed so as not to burden the equipment. Paddle speed is 100 rpm
It is above, Preferably it is 100-500 rpm.
More preferably, it is 150 to 200 rpm. 100
If it is less than rpm, the stirring effect is not good and a sufficient reaction rate cannot be obtained. When the rotation speed of the paddle is too high, the inside of the reactor becomes nearly empty due to excessive stirring, and the retention time tends to be low and the reaction rate tends to decrease, so the retention time can be taken longer and the stirring conditions are good. It is essential to create conditions.

In the method for producing stereoregular polystyrene of the present invention, the reaction temperature needs to be 120 ° C. or lower. 12
If the temperature is higher than 0 ° C, the catalyst will be deactivated and deteriorated. If the reaction temperature is too low, the reaction time will be long. More preferably, it is 20 to 120 ° C. Particularly preferably 60 to 10
0 ° C.

[0023]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. As the reactor, KRC manufactured by Kurimoto Iron Works under the following specifications and trade name KRC was used. The internal volume is 8.6 liters,
Blade diameter is 100 mm, effective cylinder length is 1000
mm, the number of paddles is 44, and the clearance between the cylinder inner wall and the paddle is 1 mm.

[0024]

Example 1 The reactor was tilted 5 degrees and the internal temperature was 80 ° C.
The paddle rotation speed was set to 200 rpm.
While supplying styrene monomer at a rate of 1 liter / hour to this reactor, methylaluminoxane as a catalyst at a rate of 75 mmol / hour and pentamethylcyclopentadienyltitanium trimethoxide at a rate of 0.15 mmol / hour for 5 hours. Polymerization was carried out.

The obtained styrene polymer having a syndiotactic structure was 2950 g, and the reaction rate was 65.6.
%Met. The syndiotacticity of the polymer in racemic pentad was 97%.

[0026]

Example 2 The same operation as in Example 1 was carried out except that the inclination angle of the reactor was 2 degrees. The obtained styrene polymer having a syndiotactic structure was 1890 g, and the reaction rate was 42.0%. The syndiotacticity of the polymer in racemic pentad was 97%.

[0027]

Comparative Example 1 The same operation as in Example 1 was carried out except that the inclination angle of the reactor was set to 0 degree. The obtained styrene-based polymer having a syndiotactic structure was 833 g, and the reaction rate was 18.5%. The syndiotacticity of the polymer in racemic pentad was 96%.

[0028]

Comparative Example 2 The same operation as in Example 2 was carried out except that the number of revolutions of the paddle of the reactor was set to 60 rpm. The obtained styrene polymer having a syndiotactic structure was 1
It was 058 g and the reaction rate was 23.5%. The syndiotacticity of the polymer in racemic pentad is 9
It was 6%.

As described above, when the reactor is tilted and used, the reaction rate can be increased, and even if the other conditions are exactly the same, the tilt angle is 2 degrees, 5 degrees as compared with the case where the tilt angle is 0 degrees. The styrene-based polymers having a syndiotactic structure of 2.3 times and 3.5 times, respectively, can be obtained.

[0030]

EFFECTS OF THE INVENTION The method for producing stereoregular polystyrene of the present invention is capable of continuously producing a styrene polymer mainly having a syndiotactic structure in a high yield as compared with the conventional method. Expected as an effective manufacturing method.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an example of a reactor used in the present invention.

FIG. 2 is a cross-sectional view schematically showing an example of a twin-case type reactor.

FIG. 3 is a cross-sectional view of a case schematically showing an example of a front form of another paddle.

FIG. 4 is a side view schematically illustrating the inclination of the reactor.

[Explanation of symbols]

 1: Reactor 2: Cylinder 3: Rotating shaft 4: Paddle 4a: Projection part 4b: Step part 5: Raw material supply port 6: Discharge port 7: Jacket 8: Paddle 9: Floor θ: Inclination angle

Claims (1)

[Claims] 1. A method for continuously producing a styrene-based polymer mainly having a syndiotactic structure from a styrene or a styrene derivative monomer by using a reactor, wherein the reactor has a pair of cylinders as shafts. Of a long double-hulled case along the outermost edge of each of the shafts, and each shaft has a structure of a multi-pair paddle slidably engaged on opposite sides thereof, and the reactor has an inclination angle. Installed at a rotation speed of the paddle of 100 rpm or more and a reaction temperature of 120 ° C.
A method for producing stereoregular polystyrene, which comprises polymerizing as follows.