JP2803074B2 - Device and method for devolatilizing volatile components of elastomer polymerization solution - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solution polymerization method,
The present invention relates to a devolatilization apparatus used for devolatilization processing for removing volatile components such as a solvent and water from a polymerization solution after polymerization, and a devolatilization method using the devolatilization apparatus. The devolatilizing device of the present invention includes BR, SB
It is suitable for devolatilization of an elastomer obtained by a solution polymerization method such as R, IR, EPR, and EPDM.

[0002]

2. Description of the Related Art Generally, in a solution polymerization method, a polymerization solution after polymerization is washed with water or the like to decompose and remove a catalyst contained therein, and then subjected to a devolatilization treatment. Alternatively, a small amount of volatile components such as water are removed, and the polymer is recovered. Conventionally, in the devolatilization process, the polymerization solution is polymerized by a flash evaporation method or the like to a polymer concentration of 30% by weight.
It has been previously concentrated to a degree and then steam stripping has been performed.

However, the above method has a problem that the amount of steam consumed is enormous, and various devolatilization methods without using steam stripping have been studied. As one of such devolatilizing treatment methods, a method using a devolatilizing extruder such as a twin-screw extruder instead of steam stripping has been studied.

[0004]

[PROBLEMS TO BE SOLVED] The use of a devolatilizing extruder for the devolatilization process has significantly reduced the steam consumption, but the following problems occur when it is applied to a polymerization solution of an elastomer such as BR or SBR. I understand. In other words, these elastomers, unlike ordinary thermoplastic resins, have the property that not only the solution viscosity rises sharply when the polymer concentration in the polymerization solution increases, but also that the solution viscosity does not decrease much even when the temperature is increased. Therefore, in the devolatilization process,
As devolatilization proceeds and the polymer concentration of the polymerization solution increases,
The required power of the twin-screw extruder suddenly increased, causing a problem that the devolatilization efficiency decreased. For this reason, in these elastomers, even after the devolatilization treatment, a considerable amount of the polymerization solvent sometimes remained. In order to solve this problem, a vent outlet is provided in the twin-screw extruder (Japanese Patent Publication No. 54-12949, Japanese Patent Publication No. 57-47685, Japanese Patent Application Laid-Open No. 63-284203), Attempts have been made to perform devolatilization treatment by adding an agent (JP-B-57-41407, JP-B-63-442, JP-B-59-91101, JP-B-61-52163, and JP-B-60-29721). Have been. However, even with these improvements, sufficient devolatilization efficiency could not be obtained.

The present invention provides a devolatilizing apparatus using a devolatilizing extruder for a volatile component of an elastomer polymerization solution, which can obtain a sufficient devolatilizing efficiency. The aim is to solve the points.

[0006]

SUMMARY OF THE INVENTION According to the present invention, an elastomer obtained by solution polymerization is prepared from BR, SBR, IR, EPR and E.
A devolatilizing extruder in which a polymerization solution selected from PDM is connected in series with a concentrator 3, 2 or more devolatilizing extruders 1a, 1b, 1c,... The present invention relates to a device for devolatilizing volatile components of an elastomer polymerization solution, wherein a flash chamber 2 is provided between an extrusion port and a feed port of a devolatilizing extruder at a later stage.

Hereinafter, the devolatilization apparatus for volatile components of the elastomer polymerization solution according to the present invention will be described in detail.

[0008] In the devolatilizer for volatile components of the elastomer polymerization solution of the present invention, the elastomer obtained by solution polymerization is obtained by connecting two or more polymerization solutions selected from BR, SBR, IR, EPR and EPDM in series. A devolatilizing device comprising devolatilizing extruders 1a, 1b, 1c,...
A flash chamber 2 is provided between an elastomer extrusion port 5a of the former devolatilizing extruder and a feed port 4a of the latter devolatilizing extruder, and a concentrator is provided in front of the first devolatilizing extruder 1a. The present invention relates to a devolatilizer (hereinafter referred to as a devolatilizer) for volatile components of an elastomer polymerization solution, wherein the devolatilizer 3 is connected to the devolatilizer. The present invention relates to a devolatilizer and a devolatilization method for a polymerization solution in which an elastomer obtained by solution polymerization is selected from BR, SBR, IR, EPR and EPDM.

Next, each component of the devolatilizer of the present invention will be described.

The devolatilizing extruders 1a, 1b, 1c...
Any devolatilizing extruder can be used as long as it is usually used, but preferably a twin-screw extruder having two screws inside is used. It is particularly preferable to use a different direction rotary type in which two screws rotate in opposite directions in a twin screw extruder. And both the meshing type and the non-meshing type can be preferably used,
The non-mesh type is particularly preferable because the transfer of the polymerization solvent or the devolatilized polymer is easy. Further, in order to prevent bending of the screw, the L / D of the screw is desirably 10 or less. The devolatilizing extruders 1a, 1b, 1c,... May be provided with a jacket on the barrel so that heating or cooling can be performed through a heat medium such as steam, hot water, cold water, or heating oil. Also, dies 6a, 6b, and 5b are provided at extrusion ports 5a, 5b, 5c,... Of the devolatilizing extruders 1a, 1b, 1c,.
6c ... and pelletizers 7a, 7b, 7c ...
May be attached. In order to devolatilize the polymerization solution (or polymer) efficiently, the flash chambers 2a, 2b, 2c,.
This is because it is preferable to supply them in the form of pellets. The size of the pores of the die is preferably about 1 to 20 mm, particularly preferably 3 to 20 mm.

The flash chambers 2a, 2b,... Feed the polymerization solution (or polymer) supplied from the extrusion ports 5a, 5b,.
・ Shoot to be supplied to Flash room 2a, 2
b,... must have a smooth surface so that the polymerization solution (or polymer) does not adhere thereto, and is preferably coated with Teflon or the like. Further, it is necessary that the inside of the flash chambers 2a, 2b,. Devolatilizing extruder 1a, 1
This is for effectively removing the polymerization solvent, unreacted monomer, and a small amount of volatile components such as water from the polymerization solution (or polymer) supplied from b, 1c. Flash chamber 2a, 2b ... internal pressure is 50-100 to
A range of about rr is preferable.

The concentrator 3 is for preliminarily concentrating the polymerization solution. The concentrator 3 is attached to a feed port of the first-stage devolatilizing extruder 1a so that the concentration process and the devolatilization process can be performed continuously. It may be. As the concentrator 3, various types such as a vent extruder, a stirring tank, and a flash evaporator are used.

FIG. 1 shows an example of a devolatilizing apparatus according to the present invention in which the concentrator 3 is not provided.

[0014]

FIG.

FIG. 2 shows an example of an embodiment using a vent extruder for the concentrator 3.

[0016]

FIG. 2

FIG. 3 shows an example of an embodiment using a stirring tank type as the concentrator 3.

[0018]

FIG. 3

In these figures, thick arrows indicate the flow of the polymerization solution or the elastomer after devolatilization.

Hereinafter, a devolatilization method using the devolatilization apparatus of the present invention will be described. First, after the polymerization is completed, the polymerization solution from which the catalyst has been decomposed and removed by washing with water or the like is introduced into the concentrator 3 and concentrated. The polymer solution before concentration usually contains 1 elastomer.
About 0 to 30% by weight is contained, and the remainder is a volatile component. In the concentrator 3, the polymerization solution is concentrated until the amount of the volatile component becomes about 1 to 30% by weight. The polymerization solution concentrated in the concentrator 3 is introduced into the first-stage devolatilizing extruder 1a as shown in FIG. The polymerization solution introduced into the devolatilizing extruder 1a is heated by friction with the screw inside the devolatilizing extruder 1a, kneaded by the rotation of the screw, and extruded from the extrusion port 5a while the surface is renewed.
Then, the volatile components are devolatilized to the first flash chamber 2a. The polymerization solution extruded from the extrusion port 5a is introduced into the first flash chamber 2a, is further devolatilized, and an elastomer substantially free of volatile components is obtained. This elastomer, as shown by the thick arrows in FIGS.
It is introduced into the feed port of the devolatilizing extruder 1b at the stage. Second
A small amount of volatile components remaining in the elastomer is devolatilized and removed by the devolatilizing extruder 1b and the second flash chamber 2b at the stage. The elastomer from which volatile components have been further removed in the second-stage devolatilizing extruder 1b and the flash chamber 2b is supplied to a third devolatilizing extruder 1c as shown by a thick arrow in FIG. 1 or FIG. It will be updated further.

[0021]

[Effect] By using the devolatilizer of the present invention, the steam consumption can be greatly reduced as compared with the conventional steam stripping method. In addition, even in the polymerization solution of an elastomer such as BR or SBR, there is almost no problem that the devolatilization efficiency decreases and the required power of the screw of the devolatilizing extruder rapidly increases as the devolatilization proceeds, and volatile components are eliminated. The elastomer having an extremely low volatile component content of 100 ppm or less can be obtained.

[0022]

EXAMPLE An example in which a BR solution was devolatilized to recover BR using the devolatilizing apparatus of the present invention will be described below. In the following examples and comparative examples, the concentrator 3 has an inner diameter of 100 m.
m, a 990 mm screw length co-rotating vent extruder was used. The vent pressure was 50 torr, the jacket temperature was 120 ° C., and the rotation speed of the screw was 60 rpm.

[0023]

EXAMPLE 1 First, BR having a Mooney viscosity of 43 (Ube Industries, Ltd., UBEPOL ^{▲ R ▼} BR150) to 30 parts by weight was added to 70 parts by weight of n- hexane, 3 at stirring vessel
After stirring for an hour, an n-hexane solution of BR was prepared. This BR solution was supplied to the concentrator 3 at a rate of 10 kg / Hr to obtain a BR having an n-hexane concentration of 2.3% by weight. This BR was supplied to the devolatilizing apparatus of the present invention, and devolatilized. The devolatilizing apparatus used was of the type shown in FIG. 1, that is, a devolatilizing extruder 1a, 1b with a flash chamber 2a provided between these devolatilizing extruders 1a, 1b. The devolatilizing extruders 1a and 1b are twin-screw extruders having an inner diameter of 65 mm and a screw L / D of 2.
24 and a single screw having a screw pitch of 40 mm. Dies 6a, 6 each having 30 holes with an inner diameter of 3 mm are provided at the tips of these devolatilizing extruders 1a and 1b.
b and the pelletizers 7a and 7b were used.
The number of rotations of the screw was 40 rpm. The above-mentioned BR was supplied at a speed of 40 kg / Hr while rotating the screw of the first-stage devolatilizing extruder 1a of the above-mentioned devolatilizing apparatus, and after confirming that BR was extruded from the tip of the die 6a, Stop the rotation of the screw and flush the inside of the flash chamber 2a for 50t.
orr and the first and second devolatilizing extruders 1
The devolatilization operation was performed by rotating the screws a and 1b.
The BR pellets extruded from the die 6b of the second-stage devolatilizing extruder 1b were received in water and collected. The n-hexane concentration in the obtained BR pellet was 80 ppm.

[0024]

Comparative Example 1 First, an n-hexane solution of BR was prepared in the same manner as in Example 1, and concentrated by the concentrator 3 to obtain a BR having an n-hexane content of 2.3% by weight. This BR was devolatilized using a twin-screw three-stage vent extruder. The screw rotation speed of the twin screw vent extruder was 40 rpm, and the jacket temperature was 130 ° C. The pressure of each vent is 2-70t
orr. The supply amount of BR was 10 kg / Hr.
However, the n-hexane concentration in the obtained BR pellet was as high as 1,500 to 2,500 ppm.

[0025]

Comparative Example 2 A devolatilization treatment was performed in exactly the same manner as in Comparative Example 1 except that 0.5 to 2 parts by weight of water was supplied to the vent extruder with respect to 100 parts by weight of BR. The n-hexane concentration in the solution is 1,200 to 2,500 pp
m, and the devolatilization efficiency was almost the same as Comparative Example 1.

[Brief description of the drawings]

FIG. 1 is a flowchart showing an example of an embodiment without a concentrator 3 in the devolatilizing apparatus of the present invention.

FIG. 2 is a flowchart showing an example of an embodiment in which a vent extruder is used for the concentrator 3 in the devolatilizing apparatus of the present invention.

FIG. 3 is a flowchart showing an example of an embodiment using a stirring tank type concentrator 3 in the devolatilizing apparatus of the present invention.

[Description of Symbols in the Drawings] 1a, 1b, 1c,... Devolatilizing extruders 2a, 2b, 2c,. 5b, 5c, ... Extrusion port 6a, 6b, 6c, ... Die 7a, 7b, 7c, ... Pelletizer

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C08F ^6/ 00-6/12

Claims (2)

(57) [Claims] An elastomer obtained by solution polymerization is BR,
A devolatilizing apparatus comprising a concentrator 3, and two or more devolatilizing extruders 1a, 1b, 1c,... Connected in series, comprising a polymerization solution selected from SBR, IR, EPR and EPDM; A flash chamber 2 is provided between an elastomer extrusion port of the devolatilizing extruder and a feed port of a subsequent devolatilizing extruder, and a concentrator 3 is connected to a stage preceding the first devolatilizing extruder 1a. A method for devolatilizing volatile components of an elastomer polymerization solution, wherein the volatile components are removed. 2. BR, SBR, IR, EPR and EPDM
A devolatilization device for recovering an elastomer, wherein a volatile component is removed from a polymerization solution obtained by solution polymerization selected from the group consisting of: