KR101298858B1 - Method for recovering solvent and apparatus therefor - Google Patents

Abstract

The present invention, the first step of injecting a polymer solution containing a thermoplastic elastomer and a solvent into the kneader; A second step of separating the thermoplastic elastomer and the solvent in the kneader; And a third step of discharging the separated thermoplastic elastomer out of the kneader and the solvent recovery apparatus to which the method can be applied. According to the present invention, an effective solvent recovery process is possible while consuming significantly lower energy than conventional methods without causing degradation of physical properties and discoloration of the final product.

Thermoplastic elastomer, styrene-based polymer, butadiene rubber, solution polymerization, kneading machine

Description

Method for recovering solvent and apparatus therefor

The present invention relates to a solvent recovery method and a solvent recovery apparatus.

Thermoplastic elastomer (thermoplastic elastomer or thermoplastic rubber) is a concept that collectively polymer materials that can be thermally processed and exhibit the properties of the rubber.

Thermoplastic elastomers may be prepared using various polymerization methods such as bulk polymerization, suspension polymerization or solution polymerization.

By the way, the polymerization method for manufacturing a thermoplastic elastomer has the following problems, respectively.

For example, when a butadiene rubber (BR) or a styrene-based polymer (ex. SBS; styrene-butadiene-styrene), which is a representative thermoplastic elastomer, is prepared by bulk polymerization, the reactant may be reacted as the reaction proceeds. Has a disadvantage that the viscosity of is rapidly increased, causing a mechanical load increase and making it difficult to control the reaction temperature.

In addition, when suspension polymerization is applied to the preparation of the thermoplastic elastomer, since a dispersant is used, there is a disadvantage that the purity of the final product is lowered. In addition, in the case of solution polymerization, since a large amount of solvent (typically, 4 to 5 times higher than that of the monomer) must be used compared to the monomer to be input, in a process such as steam stripping and distillation to recover the solvent after polymerization, The disadvantage is that a large amount of energy is consumed.

1 is a schematic view illustrating a solvent recovery process performed in the production of a general thermoplastic elastomer. As shown in FIG. 1, in a conventional method, a polymer solution obtained by solution polymerization is transferred to a steam stripper to recover a solvent, in which a large amount of energy is consumed.

In addition, since the process is in contact with water (steam) and the polymerization liquid, a decanter and a solvent purification column for removing a small amount of water remaining after the solvent recovery process should be used. In this process, excess energy is consumed again. In addition, the thermoplastic elastomer, which has undergone the steam stripper, is converted into a crumb phase through an expeller, and made into a product through a drying process of removing water, which also uses energy during the drying process.

Considering the problems of the conventional solvent recovery process as described above, if it is possible to recover the solvent directly from the polymerization liquid without contact with moisture, it is expected that the energy cost can be significantly reduced.

However, when the solvent is directly recovered from the polymerization liquid containing the thermoplastic elastomer after the polymerization reaction, the viscosity of the polymerization liquid increases rapidly as the amount of solvent recovery increases, making it difficult to operate. In addition, thermoplastic elastomers such as butadiene rubber or styrene-based polymers have a property that is weak to temperature, including many double bonds. Therefore, when the product is exposed to high temperatures in the solvent recovery process, addition reactions such as crosslinking reactions proceed, and thus the final product is discolored or its physical properties deteriorate.

The present invention has been made in consideration of the above-described problems of the prior art, and provides a solvent recovery process that can significantly reduce energy consumption and does not cause discoloration or physical property change of the final product, and a solvent recovery apparatus that can be applied to the process. For the purpose of

The present invention as a means for solving the above problems, the first step of injecting a polymer solution containing a thermoplastic elastomer and a solvent into the kneader; A second step of separating the thermoplastic elastomer and the solvent in the kneader; And

It provides a solvent recovery method comprising a third step of discharging the separated thermoplastic elastomer to the outside of the kneader.

As another means for solving the above problems, the present invention provides an inlet port through which a polymerization liquid containing a thermoplastic elastomer and a solvent is introduced; A chamber separating the thermoplastic elastomer and the solvent from the introduced polymer solution; And

Provided is a solvent recovery apparatus including a kneader having a thermoplastic elastomer discharge port capable of discharging the separated thermoplastic elastomer in the chamber.

In the present invention, while directly recovering the solvent from the polymerization liquid without contact with moisture, it is possible to solve the problem of viscosity increase occurring during the progress of the polymerization reaction and / or the removal of the polymerization solvent. In addition, in the present invention, it is possible to perform an efficient solvent removal process while significantly reducing the amount of energy consumed. In particular, according to the present invention, it is possible to perform the process at a low temperature while dealing with a material of high viscosity to ultra high viscosity under reduced pressure, thereby preventing a phenomenon such as deterioration of physical properties or product discoloration due to the addition reaction of the double bond in the thermoplastic elastomer can do. In addition, according to the present invention, a separate process of purifying a small amount of water dissolved in the recovered product can be omitted, thereby obtaining an additional energy saving effect. In addition, according to the present invention, by simplifying the device used for solvent recovery, there is an advantage that can reduce the installation and maintenance costs, and also minimize the site use rate.

The present invention, the first step of injecting a polymer solution containing a thermoplastic elastomer and a solvent into the kneader; A second step of separating the thermoplastic elastomer and the solvent in the kneader; And

It relates to a solvent recovery method comprising a third step of discharging the separated thermoplastic elastomer to the outside of the kneader.

Hereinafter, the solvent recovery method of the present invention will be described in detail.

The solvent recovery method of the present invention introduces a kneader, for example a vacuum kneader, in the process of removing the solvent from the polymerization liquid after the polymerization process for producing the thermoplastic elastomer.

In this way, by introducing a kneader (ex. A high viscosity vacuum kneader) in the solvent recovery step, the solvent can be directly recovered therefrom without bringing the polymerized liquid into contact with water, thereby advancing the polymerization reaction and / or the polymerization solvent. It is possible to solve the problem of viscosity increase occurring during the removal of. Accordingly, in the present invention, an effective solvent removal process can be performed while significantly reducing the amount of energy consumed for solvent recovery. In particular, in the present invention, since the process can be performed at a low temperature while dealing with a high viscosity or ultra high viscosity material under reduced pressure, the double bond included in the thermoplastic elastomer may cause an addition reaction, resulting in deterioration or discoloration of the product. The phenomenon can be prevented.

In the present invention, the term "thermoplastic elastomer or thermoplastic rubber" may be used in a concept including a polymer or a mixture of polymers having both thermoplastic and elastomeric properties. Such thermoplastic elastomers include styrenic polymers, polyolefin blends, elastomeric alloys, thermoplastic polyurethanes, thermoplastic copolyesters and thermoplastic polyamides. However, it is not limited thereto.

The solvent recovery method of the present invention is effective in recovering the solvent from the polymerization liquid, especially after the polymerization process of butadiene rubber (BR) or styrene polymer (styrene thermoplastic elastomer), among the thermoplastic elastomers as described above. Can be introduced.

In the case of butadiene rubber or styrene-based polymer (ex. SBS), since the polymer itself contains a double bond, problems such as discoloration of the product and deterioration of physical properties may occur when the solvent recovery process is performed at high temperature. However, according to the present invention, since the solvent recovery process can proceed effectively even at low temperatures, it is possible to prevent the above side effects.

The method of the present invention also manufactures the thermoplastic elastomer through solution polymerization, and then removes the solvent from the polymerization liquid containing the elastic body (hereinafter sometimes referred to as "solution polymerization liquid"). It can be applied effectively to the process. In the case of solution polymerization, there is an advantage in that a high purity elastomer can be obtained, compared with other polymerization methods such as suspension polymerization, but a large amount of solvent is used in the polymerization process, and excessive energy is consumed to remove the solvent. Have.

However, when applying the method of the present invention, while using a small amount of energy from the solution polymerization solution containing a large amount of solvent, it is possible to remove the solvent efficiently without causing difficulties in operating due to the viscosity increase, etc. There is this.

In the first step of the present invention, the method of injecting the polymerization liquid into the kneader is not particularly limited. In the present invention, for example, after installing a suitable inlet port to be connected to the internal chamber of the kneader, it is possible to inject a polymer solution containing a thermoplastic elastomer and a solvent into the inlet port by means such as a pump. In the present invention, the outlet of the reactor in which the polymerization reaction, such as solution polymerization is carried out directly connected to the inlet port, while continuously performing the polymerization process, the discharged polymerization solution is continuously injected into the kneader to perform a solvent recovery process You may.

The second step of the invention is the step of separating the solvent from the polymerized liquid injected inside the kneader, more specifically inside the chamber of the kneader.

In the present invention, the chamber of the kneader, in which the separation of the solvent proceeds, may have one or more shafts driven by a motor, and may further include a pressure regulating device (eg, a vacuum pump) capable of adjusting pressure or temperature inside the chamber. Vacuum control equipment), temperature control devices (eg hot wire, steam or oil circulators) and / or condensers.

In the present invention, by removing the solvent in the kneader, it is possible to perform the solvent removal process effectively without causing problems such as difficulty in operation due to the viscosity rise. Specifically, since the kneader has a paddle, disk, spectacle, or lattice-blade type in the form of a shaft impeller, even if the viscosity of the polymerization liquid increases due to the removal of the solvent, the shear force The shear force can be kept low, and the solvent can be removed without denaturing the physical properties of the product. That is, for example, in the case of an extruder having an appearance similar to a kneader, since the impeller is of a screw type, when the solvent is removed using the above, the polymerization is performed by increasing the viscosity due to the removal of the solvent. The shear force applied to the liquid is sharply increased, which may adversely affect the physical properties of the product, but the kneader does not cause such a problem. In addition, in the kneader, as the solvent is removed, the polymerization liquid is converted from the paste phase to the crumble phase, and the viscosity is drastically reduced, so that the continuous operation until the solvent is removed to an appropriate level. This is possible, and compared with other equipment, such as an extruder, large-capacity processing is possible.

In addition, when the solvent is removed from the inside of the kneader and the polymer (thermoplastic elastomer) is present in the form of a crumb, operating conditions such as an internal structure having an impeller self-cleaning function, the shape of the impeller, and the rotational speed of the shaft By adjusting the, the size of the crumb can be adjusted to the optimum range, there is an advantage that no additional equipment (ex. Pelletizer) is required after the solvent recovery process.

When the solvent separation process is performed in the second step of the present invention, the temperature inside the kneader may be 30 ° C to 150 ° C, and the pressure may be 0 barg or less, preferably -0.5 barg or less. If the temperature is less than 30 ℃, there is a fear that effective solvent separation is not carried out, if the temperature exceeds 150 ℃, there is a fear that the physical properties deteriorate, such as discoloration of the final product. In addition, when the internal pressure in the second step exceeds 0 barg, there is a fear that an effective solvent recovery process is not made. In addition, in this invention, as long as a process pressure is 0 barg or less, the minimum in particular is not restrict | limited, For example, it can control suitably in the range of -1.0 barg or more.

In the second step of the present invention, the operating level in the separation process of the solvent may also be 5% to 60%, preferably 10% to 60% of the volume of the kneader chamber. If the operation level is less than 5%, the solvent recovery efficiency may be lowered. If the operating level is more than 60%, effective solvent recovery may not be achieved.

In the present invention, the operation time of the solvent separation process (second step) can also be adjusted to about 20 to 90 minutes. However, the operation time is only one example of the present invention. In the present invention, the operation time can be freely controlled in consideration of the desired solvent recovery efficiency.

In the present invention, by carrying out the solvent recovery process under the above conditions, for example, polymerization without causing problems such as difficulty in operation due to viscosity increase, discoloration of the product due to high temperature and high shear force and / or degradation of physical properties, etc. Stable operation is possible until the amount of solvent contained in the liquid is lowered to the desired level.

In the third step of the present invention, after performing the solvent recovery process in the chamber of the kneader, the method of discharging the separated polymer and the solvent, respectively, is not particularly limited. For example, after installing the appropriate discharge port through which the separated polymer and the solvent can be discharged, the components may be discharged by means of a pump or the like.

In the present invention, in order to perform a more efficient solvent removal process, two or more kneaders may be connected in series to perform continuous operation.

For example, the method of the present invention includes a fourth step of injecting the discharged thermoplastic elastomer into the second kneader; And

A fifth step of removing the solvent contained in the thermoplastic elastomer in the second kneader may be further included.

When the method of the present invention further comprises the above step, the solvent after the polymerization reaction (ex. Solution polymerization reaction) is carried out is the first to third steps of the present invention (hereinafter referred to as "first solvent recovery step"). The solvent is first applied to remove the solvent first, and then the polymerized liquid containing the discharged thermoplastic elastomer and the solvent is successively subjected to the fourth to fifth steps (hereinafter, referred to as a “second solvent recovery step”). May be referred to as ". &Quot;, and the solvent is further removed to enable more efficient operation.

In the present invention, when the continuous process as described above, the operating conditions in the first solvent recovery process, that is, the second step of the present invention is the temperature inside the kneader (chamber) is 30 ℃ to 150 ℃, pressure This can be 0 barg or less, preferably -0.5 barg or less, the second solvent recovery process, that is, the operating conditions in the fifth step of the present invention, the temperature inside the kneader (chamber) is 60 ℃ to 150 ℃ The pressure is preferably 0 barg or less, preferably -0.8 barg or less.

If the operating temperature of the first solvent recovery step is less than 30 ° C, there is a fear that the efficient solvent recovery process does not proceed, and if it exceeds 150 ° C, the physical properties of the final product may deteriorate. In addition, when the pressure of the first solvent recovery process exceeds 0 barg, there is a fear that effective solvent recovery is not achieved. On the other hand, the lower limit of the process pressure in the first solvent recovery process is not particularly limited, for example, can be appropriately controlled in the range of -1.0 barg or more, preferably -0.8 barg or more.

In addition, if the operating temperature of the second solvent recovery step is less than 60 ℃, there is a fear that the additional solvent recovery process does not proceed, if it exceeds 150 ℃, there is a fear that the overall physical properties such as discoloration of the product occurs. . Moreover, when the operation pressure of the said 2nd solvent collection process exceeds 0 barg, there exists a possibility that an efficient solvent collection process may not be performed. On the other hand, the lower limit of the process pressure in the second solvent recovery process is not particularly limited, for example, can be appropriately controlled in the range of -1.0 barg or more.

Also, in the present invention, when the solvent recovery process is continuously performed, the operation of the first solvent recovery process (ie, the second step of the present invention) and the second solvent recovery process (ie, the fifth step of the present invention) The level can be freely controlled respectively. In the present invention, for example, the operating level in the two processes can be controlled within the range of 5% to 60%, preferably 10% to 60% of the chamber volume. If the operation level is less than 5%, the solvent recovery process may be inefficient, and if it exceeds 60%, effective solvent recovery may not be achieved.

In the present invention, the operation time of each of the first solvent separation step (second step) and the second solvent separation step (step 5) can be adjusted to about 20 to 90 minutes. However, if the operation time is only one example of the present invention, the operation time can be freely controlled in the present invention in consideration of the desired solvent recovery efficiency.

In the present invention, when the solvent recovery process is continuously performed as described above, in the first solvent recovery process, about 70 wt% to 95 wt% of the solvent included in the polymerization liquid is recovered, and the second solvent recovery process is included. At least about 99.9 wt% of the solvent can be removed.

However, the solvent removal amount is only one aspect of the present invention, and in the present invention, the amount of solvent removed can be freely adjusted according to the desired product.

In the present invention, the dryer may be further installed to communicate with the thermoplastic elastomer discharge port installed in the kneader, and the process of drying the elastomer after the solvent separation process may be further performed. At this time, the temperature condition and / or time and the like, which is performed the drying process is not particularly limited, it may be appropriately selected according to the desired product.

The present invention also provides an inlet port through which a polymerization liquid containing a thermoplastic elastomer and a solvent is introduced; A chamber separating the thermoplastic elastomer and the solvent from the introduced polymer solution; And

A solvent recovery apparatus comprising a kneader having a thermoplastic elastomer discharge port capable of discharging the separated thermoplastic elastomer in the chamber.

The solvent recovery apparatus of the present invention as described above, for example, can be effectively applied to the solvent recovery process of the present invention described above. As mentioned above, the solvent recovery apparatus of the present invention can be effectively applied as a means for separating the solvent, in particular, in the polymerization liquid obtained by the solution polymerization method. In some cases, the inlet port of the solvent recovery apparatus may be directly connected to a polymerization reactor in which a polymerization reaction (eg, a solution polymerization reaction) is performed.

2 is a conceptual diagram showing one embodiment of the solvent recovery apparatus of the present invention. As shown in FIG. 2, the solvent recovery apparatus of the present invention includes an inlet port 2 into which the polymerization liquid is introduced, a chamber 4 separating the solvent from the introduced polymerization liquid, and a solvent separated in the chamber 4. It may have a solvent discharge port 3 to be discharged and a polymer discharge port 5 to discharge the polymer. Although FIG. 2 illustrates a kneader provided with one inlet port and one outlet port, in the present invention, one or more of the above ports may be provided. In addition, the chamber of the kneader of the present invention may comprise one or more shafts 6 and a motor 1 for driving the shafts 6.

In addition, in the present invention, the shape of the impeller of the shaft may be a paddle, a disk, a spectacle, or a lattice-blade type.

The chamber may also contain suitable condensers, pressure regulators (e.g. vacuum pumps and vacuum degree regulating equipment, etc.) and / or thermostats (e.g. hot wires) to enable processes such as depressurization or boosting, solvent recovery, heating and cooling. , Steam or oil circulators, etc.).

As described above, the volume of the chamber included in the solvent recovery apparatus of the present invention may be appropriately selected in consideration of the type and amount of the polymerization liquid, operation efficiency, and the like.

The solvent recovery apparatus of the present invention may further include a second kneader connected in series with the kneader (hereinafter sometimes referred to as "first kneader"). As such, when two or more kneaders are connected in series to perform continuous operation, further increase in the efficiency of the solvent separation process is possible. 3 is a conceptual diagram illustrating a solvent recovery apparatus in which two kneaders are connected in series according to an aspect of the present invention.

As shown in FIG. 3, when the solvent recovery apparatus includes a plurality of kneaders, the polymer discharge port 15 of the first kneader may be connected to the polymerization liquid inlet port of the second kneader. Accordingly, the polymer liquid that has been subjected to the solvent removal process in the first kneader may be introduced directly into the second kneader and undergoes an additional separation process, and then the elastic body may be discharged to the discharge port 25.

The solvent recovery apparatus of the present invention may further include a dryer in communication with the polymer discharge port of the kneader. As such, since the dryer is additionally included in the solvent recovery apparatus, as shown in FIG. 4, the polymer from which the solvent is removed may be added to the dryer to further remove the remaining solvent.

Hereinafter, the present invention will be described in more detail with reference to Examples according to the present invention, but the scope of the present invention is not limited to the Examples given below.

Examples 1 to 5

After preparing butadiene rubber by a conventional solution polymerization method, a solvent recovery process was performed under the conditions shown in Table 1 using the prepared solution polymerization solution. At this time, the residual solvent amount of the polymerization solution was 71.2 wt%, and the solvent was used hexane (n-hexane) during the polymerization reaction. The vacuum kneader used in the solvent recovery process was a LIST CRP 2.5 CONTI model, had two shafts, and the volume of the chamber was 3.28 L. In addition, the chamber of the kneader was connected to a condenser, a vacuum equipment (EDWARDS (manufactured)) and a temperature control equipment (Julabo 12, Jualbo) to enable reduced pressure, solvent recovery, heating and cooling.

[Table 1]

Example One 2 3 4 5 Chamber temperature (℃) 76 84 76 78 81 Chamber pressure (barg) -0.84 -0.85 -0.86 -0.82 -0.83 Driving time (minutes) 80 80 80 60 30 Operation level (%) 13 28 23 18 17

Comparative Examples 1 and 2

Butadiene rubber-containing polymer solution (BR1208, LG Chemical Co., Ltd.) prepared by a conventional method was dried in a vacuum oven (60 ° C., 24 h), and Comparative Example 1 and the solvent was removed by a method using a steam stripper, which is a conventional solvent recovery method. The recovered and dried commercialized product was set as Comparative Example 2, and the results were compared with the above Examples.

Test Example 1

The solvent recovery results of Examples 1 to 5 and Comparative Examples 1 and 2 were evaluated by measuring the residual solvent amount, Yellowness Index, Whiteness Index, Mooney viscosity, ETA, Ash and residual metal amount. At this time, the amount of residual solvent was measured by drying the result in a vacuum oven (60 ℃, 24 h), Yellowness Index and Whiteness Index was measured using a color difference meter (Color-Eye 3100, Gretag Macbeth), ETA, Ash and Residual metals and the like were analyzed by inductively coupled plasma spectroscopy (ICP).

The results measured as described above are summarized in Table 2 below.

[Table 2]

Example Comparative example One 2 3 4 5 One 2 Residual solvent
(wt%) 0.11 0.12 0.24 0.11 0.24 71.2 trace Yellowness
Index 4.965 5.562 4.421 4.405 - 2.255 - Whiteness
Index 16.631 14.903 18.183 18.293 - 22.805 - Monney
viscosity 45.2 44.6 - - - - 45.0 ETA (wt%) - 0.14 - - - - 0.35 Ash (wt%) - 0.14 - - - - 0.09 Residual metal
(ppm) - <380 - <345 - <345 <325

As can be seen from the results of Table 2, in the embodiment to which the solvent recovery process according to the present invention is applied, there are differences depending on conditions such as temperature, pressure, and operating time inside the chamber, and the process using a conventional steam stripper. In preparation, while comparable levels of solvent recovery were possible, it was possible to operate with low energy. In addition, yellowness index, whiteness index, mooney viscosity, ETA, ash and residual metal amount, which are related to physical properties of the product (butadiene rubber), were also confirmed to be maintained at the same or superior level compared to the comparative example.

Examples 6 to 8

The solvent recovery process was carried out in a similar manner as in Examples 1 to 5, but the two kneaders were connected in series, and the process was carried out in two steps. The conditions of the solvent recovery process of the second step were as shown in Table 3 below, specifically, the first solvent recovery process to maintain a relatively low temperature and pressure conditions, the second solvent recovery process to recover the solvent by increasing the temperature and vacuum degree. . The polymerization solution used in the experiment was a solution polymerization solution prepared after preparing butadiene rubber by solution polymerization by a conventional method, wherein the amount of residual solvent was 68.9 wt%, and the solvent was n-hexane during the polymerization reaction. ) Was used.

[Table 3]

Example 6 7 8 First solvent
Recovery process Chamber temperature (℃) 82.8 81.8 93.6 Chamber pressure (barg) -0.70 -0.70 -0.70 Second solvent
Recovery process Chamber temperature (℃) 101.3 107.0 120.9 Chamber pressure (barg) -0.90 -0.90 -0.90 Total running time (minutes) 40 60 40 Operation level (%) 18 17 26

Comparative Example 3

Butadiene rubber-containing polymer solution (BR1208, LG Chem) prepared in a conventional manner was dried in a vacuum oven (60 ° C., 24 h) in Comparative Example 3.

Test Example 2

The solvent recovery results of Examples 6 to 8 and Comparative Example 3 were dried in a vacuum oven (60 ° C., 24 h) in the same manner as in Test Example 1, and then the residual solvent amount, Yellowness Index, Whiteness Index and residual metal amount were measured. It was measured and evaluated, and the results are shown in Table 4 below.

[Table 4]

Example 6 Example 7 Example 8 Comparative Example 1 Residual solvent amount in the first solvent recovery process (wt%) 2.34 2.50 1.13 68.9 Residual solvent amount in the second solvent recovery process (wt%) 0.159 0.088 0.050 68.9 Yellowness index 9.105 14.462 8.479 11.090 Whiteness index 79.217 81.100 88.376 71.894 Residual metal (ppm) 286 297 280 290

As can be seen from the results of Table 4, when the solvent recovery process is performed in two steps, and the temperature and pressure conditions in each step are controlled, the amount of residual solvent is lowered up to about 0.05 wt%, It was confirmed that the deterioration of physical properties and discoloration phenomenon of.

Examples 9 to 16

After preparing a styrene / butadiene / styrene block copolymer (SBS; styrene content: 30 wt%) by a conventional solution polymerization method, a solvent recovery process was carried out under the conditions shown in Table 5 using the prepared solution polymerization solution. Was performed. At this time, the solvent contained in the polymerization solution was a mixed solvent of hexane (n-hexane) and cyclohexane (n-hexane: cyclohexane = 15 wt%: 85 wt%). The kneader used in the solvent recovery process was a CRP 2.5 CONTI model of LIST, which had two shafts and had a volume of 3.28 L. In addition, the chamber of the kneader was connected to a condenser, a vacuum equipment, and a temperature control equipment to reduce the pressure, recovery of the solvent, heating and cooling, and the operation time during solvent recovery was about 60 to 90 minutes.

[Table 5]

Chamber temperature (℃) Chamber pressure (barg) Operation level (%)


Example 9 70 -0.9 10 10 61 -0.61 15 11 69 -0.5 10 12 82 -0.89 10 13 86 -0.88 30 14 86 -0.85 20 15 83 -0.86 10 16 78 -0.87 30

Comparative Example 4

A conventional styrene / butadiene / styrene block copolymer (LG501, LG Chem), which recovered the solvent using a steam stripper, was set as Comparative Example 4, and the results were compared with the above examples.

Test Example 3

The solvent recovery results of Examples 8 to 15 and Comparative Example 4 were evaluated by measuring the residual solvent amount, Yellowness Index, Whiteness Index, molecular weight, 300% Modulus and Hardness. At this time, the amount of residual solvent was measured by drying the result in a vacuum oven (60 ℃, 24 h), Yellowness Index and Whiteness Index was evaluated in the same manner as in the case of Test Example 1.

The results measured as described above are summarized in Table 6 below.

TABLE 6

Residual solvent
(wt%) Yellowness
Index Whiteness
Index Molecular Weight
(kDa) 300% Modulus
(N / mm ² ) Hardness


Example 9 0.41 - - 114.0 - - 10 1.02 -5.253 60.275 103.8 0.38 73.8 11 0.99 -6.545 59.595 109.3 - 72.7 12 0.40 -10.316 65.057 110.1 - 71.8 13 2.63 -8.202 84.002 106.7 0.36 72.5 14 0.02 -8.287 54.876 105.2 - 72.2 15 0.03 -10.777 62.242 109.2 - 73.5 16 1.36 -5.661 46.032 111.2 - 72.2 Comparative Example 4 trace -7.158 51.282 111.0 0.42 72.3

As can be seen from the results of Table 6, in the case of the solvent recovery process according to the present invention, there is a difference depending on the conditions such as the temperature, pressure and operating time in the chamber, when compared with the process using a conventional steam stripper, While comparable levels of solvent recovery were possible, it was possible to operate with low energy. In addition, it was confirmed that yellowness index and whiteness index, which are numerical values related to the physical properties of the product (SBS), were also comparable to or superior to those of Comparative Example 4.

Test Example 4

The products (SBS) recovered in Examples 14 and 15 and Comparative Example 4 were classified by size using a sieve, and then prepared using PMA (Plastic modified asphalt), and then the physical properties thereof were compared. At this time, PMA was prepared by putting 5 phr of SBS into 100 phr of asphalt and mixing for 1 hour in a high shear mixer and a low shear mixer, respectively. For the PMA prepared as described above, average size, softening degree, temperature when the sample started to soften and the prescribed distance sag 25.4 mm when the sample was heated under the specified conditions. , Viscosity at 135 ° C, penetration degree (measured by 0.1 mm in length of needle penetrating within a predetermined time in a sample kept at a constant temperature in a constant temperature water bath) and elongation at 5 ° C The length of the sample was increased until the sample was broken when both ends of the sample were pulled at the specified temperature and speed. The results thus measured are shown in Table 7 below.

[Table 7]

Example 14 Example 15 Comparative Example 4 average size (mm) 2 5 2 Softening degree (℃) 75 75 75 viscosity (135 ℃) (cp) 1930 1893 1900 Penetration degree (mm) 52 53 53 elongation (5 ℃) (cm) 25 25 25

As can be seen from the results of Table 7, the product (SBS) obtained through the solvent recovery process of the present invention using less energy than the conventional method shows comparable physical properties compared to the product obtained by the conventional method. Could confirm.

1 is a view showing a progress of a solvent recovery process using a steam stripper.

2 is a conceptual diagram showing one aspect of a kneader that can be used in the present invention.

3 is a view showing a solvent recovery apparatus in which two kneaders are connected in series according to an aspect of the present invention.

4 is a view showing a driving state of a solvent recovery apparatus according to an aspect of the present invention.

&Lt; Description of reference numerals &

1, 11, 21: motor

2, 12: inlet port

3, 13, 23: solvent discharge port

4, 14, 24: chamber

5, 15, 25: polymer outlet port

6, 16, 26: shaft

Claims (14)

Injecting a solution polymer solution comprising a thermoplastic elastomer and a solvent into a kneader including a shaft having an impeller of a paddle, disc, spectacle or lattice blade type; Separating the thermoplastic elastomer and the solvent in the kneader; And And a third step of discharging the separated thermoplastic elastomer out of the kneader. The method of claim 1 wherein the thermoplastic elastomer is butadiene rubber or styrene polymer. delete The process of claim 1 wherein the temperature inside the kneader in the second step is 30 ° C. to 150 ° C. and the pressure is 0 barg or less. The method of claim 1 wherein the operating level in the second step is between 5% and 60% of the volume of the chamber of the kneader. The method of claim 1, further comprising: injecting the discharged thermoplastic elastomer into the second kneader; And And a fifth step of removing the solvent contained in the thermoplastic elastomer within the second kneader. The method of claim 6, wherein the temperature inside the kneader in the second step is 30 ℃ to 150 ℃, the pressure is 0 barg or less, The temperature inside the kneader in the fifth step is 60 ° C to 150 ° C and the pressure is 0 barg or less. The method of claim 1, further comprising drying the discharged thermoplastic elastomer. An inlet port through which a solution polymerization liquid containing a thermoplastic elastomer and a solvent is introduced; A chamber separating the thermoplastic elastomer and the solvent from the introduced polymer solution; A thermoplastic elastomer discharge port capable of discharging the separated thermoplastic elastomer in the chamber; And A solvent recovery apparatus comprising a kneader having a shaft having an impeller of a paddle, distress, spectacle or lattice blade type. 10. The apparatus of claim 9, wherein the inlet port is in communication with a polymerization reactor in which solution polymerization is performed. delete 10. The device of claim 9, further comprising at least one selected from the group consisting of condensers, pressure regulators and temperature regulators. 10. The apparatus of claim 9, further comprising a second kneader in communication with the thermoplastic elastomer outlet port. 10. The apparatus of claim 9 further comprising a dryer in communication with the thermoplastic elastomer outlet port.

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