Patent Application
20240042404
The present application claims priority to Japan Patent Application No. 2022-124785 filed Aug. 4, 2022, which is incorporated herein by reference in its entirety.
The present invention relates to a polymerization apparatus for performing anionic polymerization.
As a polymerization apparatus of this type, as shown in WO 2015/093611 A, there is known a polymerization apparatus in which a plurality of raw material containers containing a raw material monomer and a polymerization initiator and a reaction container for performing a polymerization reaction are connected by a pipe, and these raw materials are continuously supplied to the reaction container to perform a polymerization reaction to synthesize a polymer.
Patent Document 1: WO 2015/093611 A
When a monomer is polymerized using a conventional polymerization apparatus as described above, components (CO2, O2, H2O) in air unintentionally mixed in a pipe or a reaction container inhibit a polymerization reaction by deactivating a polymerization initiator or a growing terminal, and a polymer is not stably synthesized in some cases. Such a phenomenon is particularly remarkable when a polymer is synthesized by anionic polymerization using a polymerization apparatus.
The present invention has been made in view of the above problems, and a main object of the present invention is to provide a polymerization apparatus capable of reducing inhibition of polymerization reaction caused by the components in air and stably performing anionic polymerization.
The inventors of the present invention conducted intensive studies to solve the above problems, and as a result, they focused on the fact that in a polymerization apparatus, a plurality of valves such as a valve for closing a channel for container replacement and a valve for adjusting the supply amount of a raw material are provided in a pipe connecting a reaction container and a raw material container, and the pipe is configured by connecting a plurality of pipe members to provide such valves. As a result of further intensive studies by the inventors of the present invention, it has been found that in a conventional polymerization apparatus, a gasket seal made of resin having low airtightness is used for a joint portion of a pipe, and a valve having low airtightness is also used, and such a joint portion of the pipe and the valve become a main mixing channel of air, and thus, the present invention has been made.
A polymerization apparatus according to the present invention is for performing anionic polymerization, the polymerization apparatus including: a raw material container that contains a raw material; a reaction container that is connected to the raw material container via a raw material supply pipe and causes anionic polymerization of the raw material supplied; and a switching valve that is provided in the raw material supply pipe and opens and closes the raw material supply pipe, wherein the raw material supply pipe includes a joint portion sealed by using a metal gasket, and the switching valve is a gas valve.
Such a polymerization apparatus, in which the joint portion of the raw material supply pipe is sealed by using a metal gasket having high airtightness, and a gas valve having higher airtightness than a valve for liquid is used as the valve provided in the raw material supply pipe, can prevent components (O2, CO2, H2O, etc.) in air that inhibit anionic polymerization reaction from being mixed through the joint portion of the raw material supply pipe or the gap between the valves. As a result, anionic polymerization can be stably performed as compared with a case in which the joint portion is sealed by using a fluororesin gasket or in which a valve for liquid is used.
As a specific aspect of the switching valve, a switching valve having a leak rate of 4×10−9 std·cm3/s or less may be exemplified.
When the leak rate of the switching valve is in such a range, mixing of components (O2, CO2, H2O, etc.) in air can be further prevented, and anionic polymerization can be stably performed.
As a specific aspect of the joint portion in the raw material supply pipe, a joint portion having a leak rate of 4×10−11 std·cm3/s or less may be exemplified.
When the leak rate of the joint portion of the raw material supply pipe is in such a range, mixing of components (O2, CO2, H2O, etc.) in air can be further prevented, and anionic polymerization can be stably performed.
In the present specification, the “leak rate” means a value obtained by performing a test in accordance with Appendix 1 (normative) Vacuum spray method (spray method) of Method for helium leak testing of JIS Z 2331:2006 or an evaluation method corresponding to the method. Note that “std·cm3/s” means “standard cc/s”.
In the polymerization apparatus, the raw material supply pipe is preferably connected to the reaction container and the raw material container by welding joining.
This configuration, in which the raw material supply pipe is connected to the reaction container and the raw material container by welding joining, can eliminate an air mixing path at a connection portion. This makes it possible to further reduce components (O2, CO2, H2O, etc.) in air to be mixed, and to more stably perform anionic polymerization in the reaction container.
In order to further reduce components in air to be mixed through the raw material supply pipe, it is preferable that the polymerization apparatus includes: a plurality of the raw material containers; and a plurality of the raw material supply pipes respectively connecting the plurality of the raw material containers and the reaction container, and all the joint portions included in the plurality of the raw material supply pipes are sealed by using a metal gasket. For the same reason, in the polymerization apparatus, all the switching valves provided in the plurality of the raw material supply pipes are preferably gas valves, and all the plurality of the raw material supply pipes are preferably connected to the reaction container and the corresponding raw material containers by welding joining.
The polymerization apparatus preferably includes a stirring mechanism that stirs the raw material supplied to the reaction container, the stirring mechanism including a stirring blade accommodated in the reaction container, and a drive mechanism that is disposed outside the reaction container and rotates the stirring blade with magnetic force.
By using such a stirring mechanism, it is possible to provide the stirring blade and the drive mechanism separately inside and outside the reaction container without providing some components (for example, a shaft member or the like) of the stirring mechanism in such a manner as to penetrate the wall of the reaction container. This makes it possible to prevent mixing of air from an installation portion of the stirring mechanism.
As a specific aspect for feeding the raw material contained in the raw material container to the raw material supply pipe, the polymerization apparatus preferably includes a pressure feeding mechanism for feeding the raw material in the raw material container to the raw material supply pipe with pressure, the pressure feeding mechanism including a pressurized gas container that contains a pressurized gas, a pressurized gas supply pipe that connects the pressurized gas container and the raw material container, a valve for pressurized gas that opens and closes the pressurized gas supply pipe, a weighing device that measures a weight of the raw material container, and a control unit that adjusts an opening degree of the valve for pressurized gas based on the weight of the raw material container acquired by the weighing device.
With this configuration, the valve for pressurized gas is not operated manually by the user, but the opening degree of the valve for pressurized gas is adjusted by the control unit, and thus, a desired amount of raw material can be accurately fed.
In the polymerization apparatus, it is preferable that the pressurized gas supply pipe includes a joint portion sealed by using a metal gasket, the valve for pressurized gas is a gas valve, and the pressurized gas supply pipe is connected to the pressurized gas container and the raw material container by welding joining.
This configuration can reduce the amount of air to be mixed from the joint portion of the pressurized gas supply pipe and the valve for pressurized gas, and anionic polymerization can be more stably performed.
When the polymerization apparatus is for performing living anionic polymerization, the effects of the present invention can be more remarkably exhibited.
With the use of each of the polymerization apparatuses having high airtightness as described above, a block copolymer satisfying 1.024≤Mw/Mn≤1.094 can be synthesized in a yield of 90% or more in a range of 44,000≤Mw≤1,023,000. Here, Mw is a weight average molecular weight, and Mn is a number average molecular weight.
The polymerization apparatus of the present invention may be a polymerization apparatus for performing anionic polymerization, the polymerization apparatus including a raw material container that contains a raw material, a reaction container that is connected to the raw material container via a raw material supply pipe and causes anionic polymerization of the raw material supplied, and a switching valve that is provided in the raw material supply pipe and opens and closes the raw material supply pipe, wherein the raw material supply pipe includes a joint portion having a leak rate of 4×10−11 std·cm3/s or less, and the switching valve has a leak rate of 4×10−9 std·cm3/s or less.
Such a polymerization apparatus also can achieve the same effects as those of the polymerization apparatus described above.
According to the present invention configured as described above, it is possible to provide a polymerization apparatus capable of reducing inhibition of polymerization reaction caused by components in air and stably performing anionic polymerization.
Hereinafter, a polymerization apparatus 100 according to an embodiment of the present invention will be described with reference to the drawings.
The polymerization apparatus 100 of the present embodiment is used for performing anionic polymerization (specifically, living anionic polymerization). Specifically, as shown in
The raw material container 1 is a highly airtight container made of metal such as stainless steel. The polymerization apparatus 100 of the present embodiment includes, as the raw material container 1, a plurality of (here, three) monomer containers 11 that contain raw material monomers to be subjected to living anionic polymerization, and an initiator container 12 that contains a polymerization initiator. In each monomer container 11, styrene (St) and methyl methacrylate (MMA) as raw material monomers and 1,1-diphenylethylene (DPE) as a binder are contained. The initiator container 12 contains secondary butyl lithium (Sec-BuLi) as a polymerization initiator. The raw material monomer and the polymerization initiator contained in each container are not limited to these materials and may be appropriately changed according to the type of the target polymer. The raw material container 1 may include a stopper container (not illustrated) that contains a reaction stopper (MeOH) or the like for stopping the polymerization reaction.
The reaction container 2 is a highly airtight container made of metal such as stainless steel. When a raw material monomer (for example, styrene) and a polymerization initiator (for example, secondary butyl lithium) are supplied at a predetermined ratio into the reaction container 2, living anionic polymerization constituted by an initiation reaction and a growth reaction is performed as illustrated in
The reaction container 2 and each of the raw material containers 1 described above are connected via a raw material supply pipe Ps. Each raw material supply pipe Ps is configured by connecting a plurality of metal pipe members, and a joint portion between the pipe members is hermetically sealed by using a gasket. Specifically, the joint portion is sealed by sandwiching the gasket between flanges of continuous pipe members and fixing both flanges by bolting. Each raw material supply pipe Ps has an upstream end connected to the upper surface of the corresponding raw material container 1 and a downstream end connected to the upper surface of the reaction container 2. Each raw material supply pipe Ps is provided with one or a plurality of switching valves Vs (hereinafter, referred to as a raw material supply valve) for opening and closing the channel. The switching valve Vs is also connected to the pipe member via a joint portion, and the joint portion between the valve Vs and the pipe member is also hermetically sealed using a gasket.
The solvent container 3 is a highly airtight container made of metal such as stainless steel, for example, and is used for storing a polymerization solvent for performing solution polymerization therein and distilling the solvent for polymerization under reduced pressure. The temperature of the solvent container 3 is controlled by a temperature control mechanism 6 so that the solvent for polymerization stored therein is maintained at a predetermined temperature. The temperature control mechanism 6 includes, for example, a constant temperature water tank, and the temperature of the solvent container 3 is adjusted to about 40° C. by immersing the solvent container 3 in the constant temperature water tank. The solvent for polymerization of the present embodiment is obtained by adding benzophenone and sodium to tetrahydrofuran (THF) and dehydrating the mixture, but the solvent is not limited to this solvent.
The solvent container 3 and the reaction container 2 are connected via a solvent pipe Pc. The solvent pipe Pc is formed by connecting a plurality of metal pipe members, and a joint portion between the pipe members is hermetically sealed by using a gasket. The solvent pipe Pc has an upstream end connected to the upper surface of the reaction container 2 and a downstream end connected to the upper surface of the solvent container 3. The solvent pipe Pc is provided with one or a plurality of solvent valves Vc for opening and closing the channel.
The polymerization apparatus 100 also includes a pressure feeding mechanism 7 for feeding the raw material in each raw material container 1 to the raw material supply pipe Ps with pressure. The pressure feeding mechanism 7 includes a pressurized gas container 71 that stores a pressurized gas, a plurality of pressurized gas supply pipes 72 that connect the pressurized gas container 71 and each raw material container 1, a valve for pressurized gas 73 provided in each pressurized gas supply pipe 72, a weighing device 74 that measures a weight of each raw material container 1, and a control unit 75 that controls an amount of a raw material to be fed with pressure to each raw material supply pipe Ps.
The pressurized gas container 71 is, for example, a gas cylinder or the like that contains a pressurized gas made of an inert gas such as argon gas or nitrogen gas. The pressure of the pressurized gas is set to be higher than the pressure in each raw material container 1 and the pressure in the reaction container 2.
The pressurized gas supply pipe 72 is configured by connecting a plurality of metal pipe members, and a joint portion between the pipe members is hermetically sealed by using a gasket, as in the case of the raw material supply pipe Ps and the like. The downstream end of each pressurized gas supply pipe 72 is connected to the upper surface of the corresponding raw material container 1.
One or a plurality of valve for pressurized gass 73 are provided in each of the pressurized gas supply pipes 72 to open and close the channel of the corresponding pressurized gas supply pipe 72.
The weighing device 74 individually measures the weight of each raw material container 1 containing the raw material (that is, the sum of the weight of the raw material container 1 itself and the weight of the contained raw material), and transmits the measurement result to the control unit 75 as weight data. The weighing device 74 may use any measurement principle such as a spring scale, a load cell type scale, or an electromagnetic type scale as long as the weight of each raw material container 1 can be measured.
The control unit 75 is a general-purpose or dedicated computer incorporating a CPU, an internal memory, and the like. The control unit 75 at least exhibits functions as a setting reception unit 75a, a weight acquisition unit 75b, and a valve control unit 75c with the CPU and its peripheral devices cooperating with each other based on a predetermined program stored in the internal memory.
The setting reception unit 75a receives a set value of the weight of the raw material to be fed with pressure to each raw material supply pipe Ps from the user and stores the set value. The weight acquisition unit 75b constantly acquires weight data indicating the weight of each raw material container 1 from each weighing device 74 and transmits the weight data to the valve control unit 75c. The valve control unit 75c adjusts the opening degree of each valve for pressurized gas 73 based on the set value received by the setting reception unit 75a and the weight of each raw material container 1. Specifically, the valve control unit 75c calculates the weight of each raw material fed with pressure from each raw material container 1 based on the temporal change in the weight of each raw material container 1, and compares the value of the weight with the set value. When the value of the raw material fed with pressure reaches the set value, the valve control unit 75c closes the valve for pressurized gas 73 and stops feeding of the raw material with pressure.
The polymerization apparatus 100 also includes a degassing mechanism 8 that degasses the inside of the reaction container 2. The degassing mechanism 8 includes a degassing pipe 81 having an upstream end connected to the reaction container 2 and a vacuum pump (specifically, a molecular turbo pump) 82 connected to a downstream end of the degassing pipe 81. The degassing pipe 81 is configured by connecting a plurality of metal pipe members, and a joint portion between the pipe members is hermetically sealed by using a gasket, as in the case of the raw material supply pipe Ps and the like. An upstream end of the degassing pipe 81 is connected to the upper surface of the reaction container 2. The degassing pipe 81 is provided with one or a plurality of degassing valves 83 for opening and closing a degassing channel.
Thus, in the polymerization apparatus 100 of the present embodiment, at least the joint portion of the raw material supply pipe Ps is sealed by using a metal gasket, and the raw material supply valve Vs is configured using a gas valve to reduce inhibition of polymerization reaction caused by components in air.
The metal gasket is made of metal such as nickel, stainless steel, or copper, for example. In the polymerization apparatus 100 of the present embodiment, at least all the joint portions included in the raw material supply pipe Ps connecting the initiator container 12 and the reaction container 2 are sealed by using a metal gasket, and here, all the joint portions of all the plurality of raw material supply pipes Ps are sealed by using a metal gasket.
Here, an aspect of the joint portion of the raw material supply pipe Ps of the present embodiment is illustrated in
This joint portion has high airtightness with the use of a metal gasket. For example, the joint portion has a leak rate of 4×1011 std·cm3/s or less in a helium leak test performed in accordance with Appendix 1 (normative) Vacuum spray method (spray method) of Method for helium leak testing of JIS Z 2331:2006.
In the present specification, the gas valve means a valve having high airtightness (that is, having a low leak rate) suitable for semiconductor manufacturing, and it may control not only gas but also liquid. More specifically, this gas valve has a leak rate of 4×10−9 std·cm3/s or less in a helium leak test performed in accordance with Appendix 1 (normative) Vacuum spray method (spray method) of Method for helium leak testing of JIS Z 2331:2006. The gas valve may be either a diaphragm type valve or a bellows seal type valve. In the polymerization apparatus 100 of the present embodiment, at least all the raw material supply valves Vs provided in the raw material supply pipe Ps connecting the initiator container 12 and the reaction container 2 are configured using gas valves, and here, all the raw material supply valves Vs provided in all the plurality of raw material supply pipes Ps are configured using gas valves. An example of an internal configuration of a bellows seal type valve is illustrated in
Further, in the polymerization apparatus 100 of the present embodiment, not only in the raw material supply pipe Ps but also in all the pipes directly or indirectly connected to the raw material containers 1, the joint portion is sealed by using a metal gasket, and the valve for opening and closing the channel is configured using a gas valve.
Specifically, all the joint portions of the solvent pipe Pc, the degassing pipe 81, and the plurality of pressurized gas supply pipes 72 are sealed by using a metal gasket. All the valves provided in these pipes are configured using gas valves.
Of the pipes constituting the polymerization apparatus 100, a bellows seal type gas valve is preferably used for the pipe through which liquid flows (the raw material supply pipe Ps and the solvent pipe Pc), and a diaphragm type gas valve is preferably used for the pipe through which gas flows (the pressurized gas supply pipe 72 and the degassing pipe 81).
In the polymerization apparatus 100 of the present embodiment, at least the raw material supply pipes Ps are connected to the reaction container 2 and the raw material containers 1 by welding joining. More specifically, all the plurality of raw material supply pipes Ps are welded and joined to the reaction container 2 and the corresponding raw material containers 1. This configuration enhances the airtightness at the connection portion between the raw material supply pipe Ps and each container.
In the present embodiment, all the pipes other than the raw material supply pipe Ps are also connected to the corresponding containers by welding joining. Specifically, each of the plurality of pressurized gas supply pipes 72 is connected to the pressurized gas container 71 and the corresponding raw material container 1 by welding joining. The solvent pipe Pc is also connected to the reaction container 2 and the solvent container 3 by welding joining, and the degassing pipe 81 is also connected to the reaction container 2 by welding joining.
Further, in the present embodiment, to improve airtightness of the reaction container 2, the stirring mechanism 5 is configured such that its constituent members do not penetrate the wall of the reaction container 2. Specifically, the stirring mechanism 5 includes a stirring blade 51 accommodated in the reaction container 2 and a drive mechanism 52 that is disposed outside the reaction container 2 (near the outer surface of the reaction container 2) and rotates the stirring blade 51 with magnetic force.
The stirring blade 51 includes a magnet member 51a rotatably provided at a position facing the drive mechanism 52 across a wall in the vicinity of the inner surface of the reaction container 2, a shaft member 51b having a rod shape coupled to the magnet member 51a, and a blade member 51c coupled to the shaft member 51b. Then, the drive mechanism 52 generates a magnetic field by, for example, applying a current to a coil (not illustrated), and rotates the magnet member 51a in the reaction container 2 using the magnetic field, thereby rotating the shaft member 51b and the blade member 51c coupled to the magnet member 51a. The drive mechanism 52 and the magnet member 51a are preferably provided near the upper surface or near the bottom surface of the reaction container 2.
Next, the operation of the polymerization apparatus 100 of the present embodiment will be briefly described.
First, a vacuum pump 82 is started, and the inside of the reaction container 2 and the inside of the raw material supply pipe Ps connected to the reaction container 2 are degassed by the degassing mechanism 8. Next, the inside of the reaction container 2 is cooled to −70° C. or less by the cooling mechanism 4. After the inside of the reaction container 2 is sufficiently degassed and depressurized, the raw material supply valve Vs and the degassing valve 83 are closed. Next, the plurality of solvent valves Vc are sequentially opened from the downstream side (reaction container 2 side), and the polymerization solvent contained in the solvent container 3 is supplied into the reaction container 2. At this time, the polymerization solvent is supplied into the reaction container 2 in a state of being vaporized in the depressurized solvent pipe Pc, is cooled in the reaction container 2, and is liquefied again. Then, after the inside of the reaction container 2 is sufficiently cooled, the pressure feeding mechanism 7 is driven to feed the raw material from each raw material container 1 with pressure, and a polymerization initiator (Sec-BuLi), a first raw material monomer (styrene), a binder (1,1-diphenylethylene), and a second raw material monomer (methyl methacrylate) are sequentially supplied into the reaction container 2 to perform polymerization reaction. Here, every time each raw material is supplied to the reaction container 2, stirring is performed by the stirring mechanism 5. Finally, a reaction stopper such as methanol is supplied to the reaction container 2 to stop the polymerization reaction. A polystyrene-polymethyl methacrylate copolymer can be thus synthesized.
According to the polymerization apparatus 100 of the present embodiment configured as described above, all the joint portions included in each pipe are sealed by using a metal gasket having high airtightness, a gas valve having high airtightness is used as the valve provided in each pipe, each pipe and the container are connected by welding joining, and the stirring mechanism 5 does not penetrate the wall of the reaction container 2. Thus, the amount of components (O2, CO2, and H2O) in air to be mixed in each pipe and the reaction container 2 can be dramatically reduced. This makes it possible to prevent deactivation of the polymerization initiator and deactivation of the growing terminal caused by mixing of H2O, and to prevent stop of the anionic polymerization reaction during the initiation reaction and the growth reaction. As a result, anionic polymerization is stably performed, and a polymer having a small variation in molecular weight distribution can be synthesized. Further, by reducing the mixing amount of CO2 or O2, the composition of the polymer to be synthesized can be brought close to the theoretical value.
The present invention is not limited to the above embodiment.
For example, the polymerization apparatus 100 of the above embodiment supplies the raw material to the raw material supply pipe Ps using the pressure feeding mechanism 7, but the present invention is not limited to this configuration. As illustrated in
In the above embodiment, all the joint portions of all the pipes included in the polymerization apparatus 100 are sealed by using a metal gasket, but the present invention is not limited to this configuration. As long as at least some of the joint portions of some of the raw material supply pipes Ps are sealed by using a metal gasket, the other joint portions may be sealed by using a gasket other than metal, such as fluororesin.
Further, in the above embodiment, all the valves provided in all the pipes included in the polymerization apparatus 100 are gas valves, but the present invention is not limited to this configuration. As long as at least some of the raw material supply valves provided in some of the raw material supply pipes Ps are gas valves, the other valves do not have to be gas valves.
In another embodiment, each pipe and the container connected to the pipe do not have to be joined by welding. Further, although the stirring mechanism 5 is configured to rotate the stirring blade 51 with magnetic force, the present invention is not limited to this configuration. The stirring mechanism 5 may be configured such that some of the constituent members penetrate the wall of the reaction container 2.
Further, the polymerization apparatus 100 of the above embodiment is for performing living anionic polymerization, but the present invention is not limited to this configuration.
The present invention is not limited to the above embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.
<Effectiveness of Sealing Joint Portion of Pipe with Metal Gasket>
The inventors of the present invention checked the effectiveness of sealing a joint portion of a pipe with a metal gasket in a polymerization apparatus by performing experiments. Specifically, with the experimental model illustrated in
First, reagent containers individually containing a raw material monomer (styrene), a polymerization initiator (Sec-BuLi), and a reaction stopper (methanol), and a thermosensor were attached to a reaction container. The reaction container was immersed in a stainless steel container filled with methanol and dry ice, and then filled with THF (solvent) by distillation under reduced pressure. After filling with THF, it was confirmed that the temperature in the reaction container was −70° C. or less. Then, the polymerization initiator was added dropwise, and the mixture was stirred. After the lapse of time, the raw material monomer was added dropwise, and the mixture was stirred. After the lapse of time, the reaction stopper was added dropwise, and the mixture was stirred to obtain a reaction liquid.
Next, pure water was added to a beaker, and the reaction liquid obtained in the polymerization experiment was added dropwise at a predetermined speed while being stirred. After the dropwise addition, the mixture was stirred, washed, and filtered to obtain a white powder. The obtained powder was dried in a vacuum dryer.
After drying, the obtained polystyrene was diluted with THF, and the molecular weight was measured in terms of polystyrene by GPC. The analysis results are shown in
As can be seen from the table of
| Number | Date | Country | Kind |
|---|---|---|---|
| 2022-124785 | Aug 2022 | JP | national |
