JP5155372B2 - Polymerization reaction apparatus and polymer production method using the same - Google Patents

Description

  The present invention relates to a polymerization reaction apparatus used for producing a polymer and a method for producing a polymer using the same.

  For the production of polymers such as (meth) acrylic polymers, continuous bulk polymerization methods and continuous solution polymerization methods in which monomers and polymerization initiators are continuously added to the polymerization reaction tank for polymerization are employed. Yes. Among these, the continuous bulk polymerization method has an advantage that a polymer with less contamination of impurities can be obtained because the polymerization reaction is carried out in a homogeneous phase without using a solvent or a dispersant. However, since the viscosity of the reaction system is extremely high, care must be taken to remove heat from the reaction system and control the polymerization temperature. On the other hand, the continuous solution polymerization method has the advantage that a polymer with less contamination of impurities can be obtained and the problem of the continuous bulk polymerization method can be reduced because the viscosity of the reaction system is low. There is a problem that decreases.

  Further, in Patent Document 1, as a method for producing a methacrylic polymer by a continuous bulk polymerization method, a completely mixed reaction tank is used, and a polymerization reaction is performed in a full liquid state substantially free of a gas phase portion in the reaction tank. A method is described.

JP-A-7-126308

  In a polymerization reaction apparatus used for the production of such a polymer, a stirring blade attached to a shaft is disposed inside the polymerization reaction tank, thereby stirring a raw material mixture containing monomers and a polymerization initiator. A polymerization reaction is carried out. Here, one end portion of the shaft is attached to the drive device, and the shaft and the stirring blade rotate when the rotational drive force is transmitted from the drive device to the shaft. The shaft is supported by a shaft seal bearing between the driving device and the polymerization reaction tank. In this shaft seal bearing portion, a shaft seal portion is provided around the shaft so that the reaction mixture in the polymerization reaction tank does not reach the driving device.

  However, when the polymerization reaction is continuously performed using the above-described polymerization reaction apparatus, the monomer in the reaction mixture or the polymer thereof adheres to the shaft-seal bearing portion, resulting in poor rotation of the shaft and the stirring blade. Therefore, there is a problem that it is difficult to perform the polymerization reaction.

  The present invention has been made in view of the above-described problems of the prior art, and a polymerization reaction apparatus capable of suppressing the monomer in the reaction mixture and the polymer thereof from adhering to the shaft-seal bearing during operation, and It aims at providing the manufacturing method of a polymer using the same.

In order to achieve the above object, the present invention is attached to a polymerization reaction tank that performs a polymerization reaction of a raw material mixture containing a monomer, and a rotatable shaft that stirs the raw material mixture in the polymerization reaction tank. A polymerization reaction apparatus comprising a stirring blade and a shaft seal bearing portion that supports the shaft, wherein the shaft seal bearing portion includes a shaft seal portion (A), the shaft seal portion (A), and the polymerization reaction. A gap formed between the tank, a shaft seal (B) provided between the gap and the polymerization reaction tank, and a liquid for introducing a liquid containing a polymerization inhibitor into the gap It has constructed shaft seal portion from the inlet, and, the liquid introduced from the liquid introduction port is configured to be discharged into the polymerization reactor from the gap portion, the shaft seal part (B) is formed by a lip seal, the polymerization reaction To provide a location.

  In the conventional polymerization reaction apparatus, when the polymerization reaction is continuously performed for a long period of time, the monomer in the reaction mixture or the polymer thereof adheres to the vicinity of the shaft-seal bearing in the polymerization reaction apparatus, and the shaft and the stirring blade There was a problem of causing rotation failure. Such a problem is caused when the shaft-sealed bearing portion is provided at a position in contact with the reaction mixture in the polymerization reaction tank when performing the polymerization reaction in a state where the gas phase portion exists in the polymerization reaction tank, or in the polymerization reaction tank. This was particularly remarkable when the polymerization reaction was carried out in a full liquid state having substantially no gas phase portion therein because the reaction mixture easily reached the shaft-sealed bearing portion. In the polymerization reaction apparatus of the present invention, a liquid inlet for introducing liquid into the gap between the shaft seal part (A) in the shaft seal bearing part and the polymerization reaction tank is provided, and the introduced liquid is Then, it is discharged into the polymerization reaction tank through a gap between the inner wall surface of the shaft seal bearing portion and the shaft. Therefore, a liquid flow from the shaft-seal bearing portion toward the polymerization reaction tank is formed, and the monomer in the reaction mixture hardly reaches the vicinity of the shaft-seal bearing portion. In addition, since the liquid introduced into the polymerization reaction tank contains a polymerization inhibitor, the polymerization reaction of the monomer in the vicinity of the shaft seal bearing portion is also suppressed. Furthermore, since the shaft seal portion (B) is provided, the reaction mixture in the polymerization reaction tank is prevented from flowing back and entering the shaft seal bearing portion. The shaft seal bearing portion has a shaft seal portion composed of the shaft seal portion (A), the gap portion, the liquid inlet, and the shaft seal portion (B), and from the liquid inlet By being configured so that the liquid to be introduced is discharged from the void portion into the polymerization reaction tank, adhesion of the monomer and the polymer thereof to the vicinity of the shaft seal bearing portion is sufficiently suppressed, Even when a long-term operation is continuously performed, it is possible to sufficiently suppress the rotation failure of the shaft and the stirring blade.

  In the polymerization reaction apparatus of the present invention, the shaft seal part (A) is preferably formed by a mechanical seal. Thereby, there is no deterioration of a shaft seal part (A) even under high temperature, and long-term continuous operation can be performed stably.

  In the polymerization reaction apparatus of the present invention, the shaft seal portion (B) is preferably formed by a lip seal. Thereby, it is more sufficiently suppressed that the reaction mixture in the polymerization reaction tank flows backward and enters the shaft seal bearing portion.

  The present invention is also a method for producing a polymer using the polymerization reaction apparatus of the present invention, wherein the single liquid is introduced while introducing the liquid containing the polymerization inhibitor into the gap through the liquid inlet. Provided is a method for producing a polymer, which comprises a step of continuously supplying the raw material mixture containing a monomer into the polymerization reaction tank and performing a polymerization reaction.

  According to such a method for producing a polymer, by using the polymerization reaction apparatus of the present invention, a polymerization reaction is carried out while introducing a liquid containing a polymerization inhibitor from a liquid inlet, so that a single amount is provided in the vicinity of the shaft-seal bearing portion. It is possible to sufficiently suppress the adhesion of the body and the polymer thereof, and the polymer can be continuously produced over a long period of time without causing problems such as poor rotation of the shaft and the stirring blade.

  In the method for producing a polymer of the present invention, the liquid introduced from the liquid inlet is preferably a liquid obtained by dissolving the polymerization inhibitor in the monomer. In such a liquid, a monomer that is the same component as the monomer contained in the raw material mixture is used as a solvent for dissolving the polymerization inhibitor. Therefore, it can suppress that an impurity mixes in the polymer obtained compared with the case where another solvent is used.

  According to the present invention, it is possible to suppress the monomer in the reaction mixture and the polymer thereof from adhering to the shaft-sealed bearing portion during operation, and continuous operation over a long period of time without causing the problem of rotation failure of the shaft and the stirring blade. Can be provided, and a polymer production method using the same.

1 is a schematic configuration diagram of a polymerization reaction apparatus according to a preferred embodiment of the present invention. It is a fragmentary sectional view of a shaft seal bearing part of a polymerization reaction device concerning a suitable embodiment of the present invention.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a schematic configuration diagram of a polymerization reaction apparatus according to a preferred embodiment of the present invention. As shown in FIG. 1, a polymerization reaction apparatus 100 includes a polymerization reaction tank 10 that performs a polymerization reaction of a raw material mixture containing a monomer, and a rotatable shaft 20 that stirs the raw material mixture in the polymerization reaction tank 10. And a shaft sealing bearing portion 30 that supports the shaft 20. The polymerization reaction apparatus 100 also includes a raw material supply port 12 for supplying the raw material into the polymerization reaction tank 10 and a liquid (syrup-like) polymer composition containing the polymer produced by the polymerization reaction. 10 and a polymer composition outlet 14 for discharging to the outside. Further, the polymerization reaction apparatus 100 is provided with a jacket 16 for adjusting the temperature of the outer wall surface of the polymerization reaction tank 10.

  FIG. 2 is a partial cross-sectional view of a shaft seal bearing portion of a polymerization reaction apparatus according to a preferred embodiment of the present invention. As shown in FIG. 2, the shaft seal bearing portion 30 includes a shaft seal portion (A) 32, a gap portion 34 formed between the shaft seal portion (A) 32 and the polymerization reaction tank 10, and the gap portion 34. And a shaft seal portion (B) 38 provided between the polymerization reaction tank 10 and a shaft sealing portion 40 comprising a liquid inlet 36 for introducing a liquid containing a polymerization inhibitor into the gap portion 34. Have. The liquid containing the polymerization inhibitor introduced into the gap portion 34 is discharged from the gap portion 34 into the polymerization reaction tank 10. In the present embodiment, a shaft seal portion (B) 38 is provided between the gap portion 34 and the polymerization reaction tank 10. Examples of the shaft seal portion (B) 38 include a lip seal and a PTFE (polytetrafluoroethylene) bush. Among these, a lip seal is preferable. The shaft seal portion (B) 38 is preferably made of PTFE. By using the shaft seal part (B) 38 made of PTFE, it is possible to improve the chemical resistance against monomers and the like, and to maintain a good sealing property even if the shaft is shaken. Even when the operation is continuously performed, the sealing effect can be maintained. Further, a drive device (not shown) for rotating the shaft 20 is provided above the shaft seal portion (A) 32 (in the direction opposite to the polymerization reaction tank 10).

  The shaft seal portion (A) 32 only needs to be formed in the form of a known shaft seal, but problems such as poor sealing due to the influence of the liquid introduced into the gap portion 34 are unlikely to occur. As described above, it is preferably formed by a mechanical seal. The type of the mechanical seal is not particularly limited, and a known type of mechanical seal can be used. For example, as shown in FIG. 2, the mechanical seal includes a rotary ring 32a fixed to the shaft 20 side and a fixed ring 32b fixed to the shaft seal bearing body (casing) side, and a spring (not shown). The rotating ring 32a and the stationary ring 32b are pressed against each other with a constant force so as to be in close contact with each other. Moreover, in order to reduce the friction of the contact surface of the rotating ring 32a and the fixed ring 32b, the inside of a mechanical seal is filled with the mechanical seal liquid 32c. In FIG. 2, the structure by the mechanical seal which has two combinations of the rotating ring 32a and the fixed ring 32b, ie, a double mechanical seal, is shown. The mechanical seal liquid 32c is normally continuously supplied from a mechanical seal liquid inlet (not shown) using a pump or the like, and continuously discharged from a mechanical seal liquid outlet (not shown). The mechanical seal liquid is preferably circulated and supplied. The filling pressure is appropriately set depending on the size of the polymerization reaction apparatus 100, the polymerization conditions, and the like, but is set higher than the pressure of the liquid introduced into the gap 34.

  As the mechanical seal liquid 32c, a known mechanical seal liquid can be used without particular limitation. Specific examples include adipic acid esters, phthalic acid esters, diisobutyric acid esters, acetylated glycerides, and the like. Examples of adipic acid esters include bis (2-ethylhexyl) adipate, diisononyl adipate, diisodecyl adipate, and the like. Examples of the phthalic acid ester include bis (2-ethylhexyl) phthalate, diisononyl phthalate, diisodecyl phthalate, and the like. Examples of the diisobutyric acid ester include 2,2,4-trimethyl-1,3-pentanediol diisobutyrate. Examples of the acetylated glyceride include glycerin diacetomonolaurate, glycerin diacetomonostearate, glycerin diacetomonooleate, glycerin diacetomonolinoleate, glycerin diacetomono12-hydroxystearate, glycerin diacetomonomyristate, glycerin diacetomonopalmi Tate, glycerol diacetomonolaurate, glycerol monoacetomonostearate, glycerol monoacetomonomyristate, glycerol monoacetomonopalinate, glycerol monoacetomonoricinoleate, glycerol monoacetomono12-hydroxystearate, glycerol monoacetomonobe Henate, glycerol monoacetomonooleate, glycerol monoacetomonolaurate, glycerol monoacetate Oleate, glycerol mono acetic Jiri ricinoleate, glycerol mono-acetoacetate dicaprylate, glycerol mono-acetoacetate dilaurate, glycerin mono- acetonate distearate and the like. Among these, adipic acid esters and diisobutyric acid esters are preferable, and adipic acid esters are particularly preferable. In the case of producing a (meth) acrylic polymer, particularly polymethyl methacrylate (PMMA) as a polymer, adipic acid ester does not accelerate the monomer polymerization reaction even if mixed in the reaction mixture. There is an advantage that adverse effects such as causing coloration of the obtained polymer hardly occur.

  The material of the rotating ring 32a and the fixed ring 32b is not particularly limited as long as it is made of a known material. Examples of the material of the rotating ring 32a and the stationary ring 32b include carbon, silicone carbide, cemented carbide, and chromium oxide coating.

  The shaft seal portion (A) 32 may be formed by a gland packing, a Wilson seal, an oil seal, a labyrinth seal, an O-ring seal, a bellows seal, etc. in addition to a mechanical seal.

  The liquid introduced into the gap 34 from the liquid inlet 36 is a liquid containing a polymerization inhibitor, and is a liquid in which the polymerization inhibitor is dissolved in a solvent that does not promote the polymerization reaction of the monomers in the reaction mixture. Is preferred. Examples of the solvent include those contained in organic solvents such as toluene, xylene, ethylbenzene, methyl isobutyl ketone, methyl alcohol, ethyl alcohol, octane, decane, cyclohexane, decalin, butyl acetate, pentyl acetate, and raw material mixtures. The same monomers as those mentioned above are mentioned, and among them, the same monomers as those contained in the raw material mixture are preferably used. The monomer is usually liquid. When the said monomer is used as a solvent, it can suppress that an impurity mixes in the polymer obtained. In addition, since the said liquid contains the polymerization inhibitor, the polymerization reaction of the monomer which is a solvent is suppressed also in the said liquid.

  Examples of the polymerization inhibitor include hydroquinone, hydroquinone monomethyl ether, tert-butylcatechol, 4-methoxy-1-naphthol, 1,4-naphthoquinone, 2,4-dimethyl-6-tert-butylphenol, phenothiazine, benzo Examples include phenothiazine, dinitrobenzene, p-phenyldiamine, dimethyldithiocarbamate and the like. Among these, 2,4-dimethyl-6-tert-butylphenol is preferable from the viewpoint that even if it remains in the polymer, it is difficult to exert adverse effects such as coloring. The polymerization inhibitor to be used is appropriately selected according to the polymer to be produced and the monomer used as the raw material.

  The content of the polymerization inhibitor in the liquid is preferably 5 to 2000 ppm by mass, more preferably 10 to 500 ppm by mass based on the total amount of the liquid. When this content is larger than the above range, the ratio of the polymerization inhibitor contained in the polymer increases, and the polymer tends to be slightly colored. In addition, when the content is smaller than the above range, the effect of suppressing the polymerization reaction of the raw material monomer in the vicinity of the shaft-seal bearing portion 30 tends to be reduced, and when the monomer is used as a solvent. Tends to decrease the effect of suppressing the polymerization reaction of the monomer.

  The flow rate of the liquid to be introduced is appropriately set according to the size of the polymerization reaction apparatus 100, the polymerization conditions, and the like, but is usually 0.01 to 5 L / min, preferably 0.1 to 3 L / min. When the flow rate of the liquid is larger than the above range, the ratio of the polymerization inhibitor contained in the polymer is high, and the polymer tends to be slightly colored, and when the flow rate is smaller than the above range, the unreacted in the reaction mixture. There exists a tendency for the effect which suppresses a monomer and its polymer to penetrate | invade into the shaft seal bearing part 30 to fall. The polymerization reaction of the raw material mixture in the polymer reaction tank 10 is performed while continuously supplying the liquid from the liquid inlet 36 to the gap 34 at the above flow rate.

  In the polymerization reaction apparatus 100, the liquid introduction port 36 is provided in the gap portion 34, and the inside of the gap portion 34 is brought into a pressurized state by introduction of the liquid, so that the pressure is higher than that in the polymerization reaction tank 10. For this reason, it can fully suppress that a reaction mixture penetrate | invades into the shaft seal bearing part 30 from the polymerization reaction tank 10, and it functions as a shaft seal collectively. A suitable range of the pressure in the gap 34 is appropriately set according to the size of the polymerization reaction apparatus 100, the polymerization conditions, etc., but it is set higher than the pressure in the polymerization reaction tank 10 and mechanical seal liquid. It is preferable to make it lower than the filling pressure of 32c. It is preferable to install a safety device such as a relief valve in the liquid feed pump main body so that the pressure does not increase too much. Further, since the polymerization reaction apparatus 100 is provided with a pressure gauge and a safety valve according to the maximum operating pressure, the pressure in the gap 34 is set within a range where the safety valve does not operate. In FIG. 1, the shaft seal bearing part 30 is installed at the uppermost part of the reaction tank 10, but may be installed at the lower part of the reaction tank 10. When the polymerization reaction apparatus 100 includes the shaft-sealed bearing portion 30 having the above-described configuration, when the polymerization reaction is performed in a state where the gas phase portion is present in the polymerization reaction tank, the shaft-sealed bearing portion is a reaction mixture in the polymerization reaction tank. The shaft-sealed bearing part comes into contact with the reaction mixture in the polymerization reaction tank when the polymerization reaction is carried out in a full liquid state where there is substantially no gas phase part in the polymerization reaction tank. Even in this case, it is possible to sufficiently prevent the reaction mixture from entering the shaft seal bearing portion 30 from the polymerization reaction tank 10.

  The polymerization reaction apparatus 100 of the present embodiment is a continuous polymerization apparatus used for a continuous bulk polymerization method or a continuous solution polymerization method, and the polymerization reaction tank 10 has a substantially completely mixed state inside the reaction tank by a stirring blade 22. It can be done. As the shape of the stirring blade 22, Sumitomo Heavy Industries, Ltd. Max blend blade, paddle blade, double helical ribbon blade, MIG (Mig) blade, Shinko Pantech Co., Ltd. full zone blade, etc. are used. Not. In order to enhance the stirring effect, it is desirable to attach a baffle in the polymerization reaction tank 10.

It goes without saying that the higher the stirring efficiency of the polymerization reaction apparatus 100, the more preferable the stirring power is, which is not preferable because it only adds an extra amount of heat to the reaction vessel 10. Therefore, the stirring power is preferably 0.5 to 20 kW / m ³ , more preferably 1 to 15 kW / m ³ . The stirring power is preferably increased as the viscosity of the liquid content, that is, the polymer content increases.

  It is preferable that the inside of the polymerization reaction tank 10 is in a fully filled state with substantially no gas phase. By making the liquid full, adhesion and generation of the polymer on the inner wall surface of the gas phase portion and the gas-liquid interface can be suppressed, and deterioration in quality due to mixing into these products can be suppressed. In addition, since the entire volume of the polymerization reaction tank 10 can be effectively used, productivity can be improved.

  In order to fill the inside of the polymerization reaction tank 10, as shown in FIG. 1, the outlet of the polymer composition after the polymerization reaction (polymer composition outlet 14) is installed at the top of the reaction tank 10. Is the simplest. In this case, the raw material (initiator composition and monomer composition) supply port 12 is preferably provided in the lower part of the polymerization reaction tank 10 as shown in FIG. In addition, it is desirable not to generate the gas of the raw material monomer in the polymerization reaction tank 10, and for that purpose, the pressure in the polymerization reaction tank 10 is equal to or higher than the vapor pressure of the reaction mixture at the temperature in the reaction tank 10. It is preferable to use a pressure. This pressure is about 1.0 to 2.0 MPa in terms of gauge pressure.

  Moreover, it is preferable to make the inside of the polymerization reaction tank 10 into the heat insulation state from which the heat does not go in and out substantially from the outside. That is, it is preferable that the temperature in the reaction tank and the temperature on the outer wall surface side of the reaction tank are substantially the same. Specifically, for example, as shown in FIG. 1, a jacket 16 is installed on the outer wall surface side of the reaction tank, and the outer wall temperature of the reaction tank is made to follow the temperature in the reaction tank by using steam or other heating medium. This can be done by setting the temperature.

  The jacket 16 covers substantially the entire polymerization reaction tank 10, and a reaction medium is introduced by introducing a heat medium such as steam, hot water or an organic heat medium into the jacket 16 from a heat medium supply path (not shown). The tank 10 is appropriately heated or kept warm. The temperature of the jacket 16 can be appropriately adjusted depending on the temperature or pressure of the supplied heat medium. The heat medium introduced into the jacket 16 is removed from a heat medium discharge path (not shown).

  The reason why the polymerization reaction tank 10 is in an adiabatic state is that the polymer can be prevented from adhering to the inner wall surface of the reaction tank and the self-controllability that stabilizes the polymerization reaction and suppresses the runaway reaction is brought about. In addition, it is not preferable to make the temperature of the inner wall of the reaction tank too higher than the temperature of the inner solution because extra heat is applied to the reaction tank. Although it is preferable that the temperature difference between the inside of the reaction tank and the outer wall of the reaction tank is small, it may be adjusted within a range of a swing width of about ± 5 ° C.

  In the present embodiment, it is preferable to balance the heat generated in the polymerization reaction tank 10, that is, the polymerization heat and the stirring heat, with the amount of heat taken away by the liquid (syrup-like) polymer composition exiting the polymerization reaction tank 10. . The amount of heat carried away by the polymer composition is determined by the amount of the polymer composition, specific heat, and temperature (polymerization temperature).

  Although superposition | polymerization temperature is based also on the kind of radical polymerization initiator to be used, Preferably it is about 120-180 degreeC, More preferably, it is 130-180 degreeC. If this temperature is too high, the syndiotactic properties of the resulting polymer will be low, the amount of oligomer produced will increase, and the heat resistance of the resin will tend to be low.

  The average residence time of the raw material mixture in the polymerization reaction tank 10 is preferably 15 minutes to 2 hours, more preferably 20 minutes to 1.5 hours. If this time is longer than necessary, the amount of oligomers such as dimers and trimers increases, and the heat resistance of the product tends to decrease. The average residence time can be adjusted by changing the amount of monomer supplied per unit time.

  The raw material is supplied into the polymerization reaction tank 10 through an initiator supply path 51 and a monomer supply path 52 through an initiator composition containing a radical polymerization initiator and a monomer composition containing a monomer, respectively. It may be supplied separately from the supply port 12, or the initiator supply path 51 between the supply port 12 and the initiator supply pump 53, and the monomer between the supply port 12 and the monomer supply pump 54 The initiator composition and the monomer composition may be mixed and supplied from the supply port 12 by merging with the supply path 52, or a supply port (not shown) separate from the supply port 12 may be provided. Further, the initiator composition and the monomer composition may be supplied from separate supply ports. Here, the initiator composition is, for example, a mixture of a radical polymerization initiator, a monomer, and a chain transfer agent, and the monomer composition is, for example, a mixture of a monomer and a chain transfer agent. It is.

  The initiator composition is prepared in the initiator preparation tank 101. As shown in FIG. 1, the prepared initiator composition is continuously fed into the polymerization reaction tank 10 through the initiator supply path 51 that connects the initiator preparation tank 101 and the polymerization reaction tank 10 by the initiator supply pump 53. Supplied. On the other hand, the monomer composition is prepared in the monomer preparation tank 102. The prepared monomer composition is prepared by the monomer supply pump 54 as shown in FIG. Are continuously supplied into the polymerization reaction tank 10 through the monomer supply path 52 connecting the polymerization reaction tank 10 and the polymerization reaction tank 10.

  As the initiator compounding tank 101 and the monomer compounding tank 102 used in the present embodiment, a compounding tank provided with the same stirring device as the above-described polymerization reaction tank 10 can be used. In the initiator preparation tank 101, the radical polymerization initiator is completely dissolved in the monomer to obtain an initiator liquid. Moreover, the temperature in the initiator preparation tank 101 is maintained at a temperature at which the polymerization reaction does not proceed, and is preferably maintained at −20 to 10 ° C. On the other hand, the temperature in the monomer preparation tank 102 is maintained at a temperature at which the monomer does not volatilize, and is preferably maintained at −20 to 10 ° C.

  The initiator supply pump 53 and the monomer supply pump 54 are not particularly limited, but the supply flow rates of the initiator composition and the monomer composition into the polymerization reaction tank 10 can be set to constant amounts. A pump is preferred. Specifically, a multiple reciprocating pump is preferable, and a non-pulsating constant pump such as a double non-pulsating metering pump or a triple non-pulsating metering pump is more preferable.

  In addition, a heating / cooling device is connected to the initiator supply path 51 and the monomer supply path 52 that connect the initiator preparation tank 101 and the monomer preparation tank 102 and the polymerization reaction tank 10, thereby the polymerization reaction tank 10. You may adjust the temperature of the raw material supplied to.

  The amount of the initiator composition supplied from the initiator preparation tank 101 to the polymerization reaction tank 10 varies depending on the capacity of the polymerization reaction tank 10 and the like. For example, when the capacity of the polymerization reaction tank 10 is 10 L, it is preferably 0.1. -10 kg / hr, more preferably 0.5-5 kg / hr. Further, the amount of monomer composition supplied from the monomer preparation tank 102 to the polymerization reaction tank 10 varies depending on the capacity of the polymerization reaction tank 10 and the like, but preferably when the capacity of the polymerization reaction tank 10 is 10 L, for example. Is 4 to 40 kg / hr, more preferably 10 to 30 kg / hr.

  In addition, in order to prevent the influence of dissolved oxygen during monomer preparation, it is common to remove the dissolved oxygen by bubbling an inert gas in the monomer preparation tank 102 or by degassing under reduced pressure. However, in the method of this embodiment, it is not always necessary to remove it strictly, and the polymerization reaction can be carried out stably even if it is present at about 1.5 to 3 ppm. When supplying the prepared monomer composition to the polymerization reaction tank 10, it is possible to filter with a filter having a size according to the purpose in order to remove foreign matters, and when the obtained polymer is used as an optical device material, Particularly desirable.

  The polymer produced by the polymerization reaction using the polymerization reaction apparatus 100 is taken out from the polymer composition outlet 14 of the polymerization reaction tank 10 as a liquid (syrup-like) polymer composition, and the polymer composition is derived. It is transferred and collected via the path 55. Since this polymer composition contains unreacted raw material monomers, the polymer composition is heated if necessary to evaporate and separate volatile components mainly composed of unreacted raw material monomers. As a method for transferring the polymer composition, the method described in JP-B-4-48802 is suitable. Further, as a method for evaporating and separating the volatile matter, a method using a devolatilizing extruder is known. For example, Japanese Patent Publication No. 51-29914, Japanese Patent Publication No. 52-17555, Japanese Patent Publication No. 1-53682. The methods described in JP-A No. 62-89710, JP-A No. 3-49925 and the like are suitable.

  In addition, since the polymerization reaction tank 10 used in the present invention is a complete mixing type reaction tank, the polymerization rate converted from the raw material monomer to the polymer in the reaction tank is approximately the polymer composition. This corresponds to the polymer content in the product. In the present invention, the polymerization rate is not particularly limited, but is usually set to 40 to 70% by mass. The higher the polymerization rate, the higher the productivity of the polymer. However, the viscosity of the reaction system becomes high, and a large stirring power is required. Further, the lower the polymerization rate, the lower the productivity of the polymer and the greater the burden for recovering unreacted raw material monomers.

  The raw material monomer separated and recovered from the polymer composition is stored in the monomer recovery tank, and then supplied again to the monomer preparation tank 102 as necessary to be used for the polymerization reaction. be able to. For the recovered raw material monomer, a polymerization inhibitor is present at a ratio of 2 to 8 ppm so that the polymerization reaction does not proceed while it is stored in the monomer recovery tank, It is preferable that the oxygen concentration is set to 2 to 8% by volume and further stored in a cooled state, specifically at a low temperature of about 0 to 5 ° C., for example.

  In the present invention, the monomer, radical polymerization initiator and chain transfer agent are selected according to the polymer to be produced. Hereinafter, as a preferred embodiment, a (meth) acrylic polymer such as polymethyl methacrylate is used. The raw material for producing the polymer will be described. In the present specification, “(meth) acryl” means “acryl” and “methacryl” corresponding to it.

  Although it does not specifically limit as a monomer used as a raw material of a (meth) acrylic-type polymer, For example, (meth) acrylic acid alkyl (thing whose carbon number of an alkyl group is 1-4) is independent, or A mixture of 80% by mass or more of an alkyl (meth) acrylate (wherein the alkyl group has 1 to 4 carbon atoms) and 20% by mass or less of another vinyl monomer copolymerizable therewith. Examples of the alkyl (meth) acrylate alkyl (the alkyl group having 1 to 4 carbon atoms) include methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, and the like. Of the alkyl (meth) acrylates, methyl (meth) acrylate is preferred.

  Examples of the copolymerizable vinyl monomer include alkyl (meth) acrylates (alkyl group having 1 to 4 carbon atoms) such as benzyl (meth) acrylate and 2-ethylhexyl (meth) acrylate. (Meth) acrylic acid esters other than those above; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, maleic anhydride, itaconic anhydride, or acid anhydrides thereof; acrylic acid 2- Hydroxyl group-containing monomers such as hydroxyethyl, 2-hydroxypropyl acrylate, monoglycerol acrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, monoglycerol methacrylate; acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, di Acetone acrylic , Nitrogen-containing monomers such as dimethylaminoethyl methacrylate; allyl glycidyl ether, glycidyl acrylate, epoxy group-containing monomers such as glycidyl methacrylate; styrene, styrene monomers such as α- methyl styrene.

  When applying this invention to the production | generation of a (meth) acrylic acid ester type polymer, as a polymerization initiator supplied to a reaction tank, a radical polymerization initiator is mentioned, for example. Examples of the radical polymerization initiator include azobisisobutyronitrile, azobisdimethylvaleronitrile, azobiscyclohexanenitrile, 1,1′-azobis (1-acetoxy-1-phenylethane), dimethyl 2,2 ′. -Azo compounds such as azobisisobutyrate and 4,4'-azobis-4-cyanovaleric acid; benzoyl peroxide, lauroyl peroxide, acetyl peroxide, capryel peroxide, 2,4-dichlorobenzoyl peroxide, Isobutyl peroxide, acetylcyclohexylsulfonyl peroxide, t-butylperoxypivalate, t-butylperoxyneodecanoate, t-butylperoxyneoheptanoate, t-butylperoxy-2-ethylhexanoate , 1,1-di-t-butylperoxycyclohexane, 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane, 1,1-di-t-hexylperoxy-3,3,5 -Trimethylcyclohexane, isopropyl peroxydicarbonate, isobutyl peroxydicarbonate, s-butyl peroxydicarbonate, n-butyl peroxydicarbonate, 2-ethylhexyl peroxydicarbonate, bis (4-t-butylcyclohexyl) per Oxydicarbonate, t-amylperoxy-2-ethylhexaenoate, 1,1,3,3-tetramethylbutylperoxy-ethylhexanoate, 1,1,2-trimethylpropylperoxy-2-ethyl Hexanoate, t-butyl peroxyisopropyl mono -Bonate, t-amyl peroxyisopropyl monocarbonate, t-butyl peroxy-2-ethylhexyl carbonate, t-butyl peroxyallyl carbonate, t-butyl peroxyisopropyl carbonate, 1,1,3,3-tetramethylbutyl per Oxyisopropyl monocarbonate, 1,1,2-trimethylpropyl peroxyisopropyl monocarbonate, 1,1,3,3-tetramethylbutyl peroxyisononate, 1,1,2-trimethylpropyl peroxyisononate, t -Organic peroxides such as butyl peroxybenzoate. These polymerization initiators may be used alone or in a combination of two or more.

  Although it does not specifically limit as a compounding quantity of a radical polymerization initiator, Usually, it is 0.001-1 mass part with respect to 100 mass parts of monomers of a raw material. When two or more kinds of radical polymerization initiators are mixed and used, the total amount used may be within this range. The polymerization initiator supplied to the reaction vessel is selected according to the type of polymer to be generated and the raw material monomer to be used, and is not particularly limited in the present invention. As the initiator, those having a half-life at the polymerization temperature of 1 minute or less are preferable. If the half-life at the polymerization temperature exceeds 1 minute, the reaction rate becomes slow, which may make it unsuitable for a polymerization reaction in a continuous polymerization apparatus. The relationship between the temperature and the half-life of the radical polymerization initiator is described in various documents and technical data of the manufacturer for each type of radical polymerization initiator. In the present invention, values described in known product catalogs such as Wako Pure Chemical Industries, Ltd. or Kayaku Akzo Corporation were used.

  When the present invention is applied to the production of a (meth) acrylic acid ester polymer, a chain transfer agent can be blended in the reaction vessel in order to adjust the molecular weight of the polymer to be produced. The chain transfer agent may be any of monofunctional and polyfunctional chain transfer agents. Specifically, for example, propyl mercaptan, butyl mercaptan, hexyl mercaptan, octyl mercaptan, 2-ethylhexyl mercaptan, dodecyl mercaptan Alkyl mercaptans such as phenyl mercaptan and thiocresol; mercaptans having 18 or less carbon atoms such as ethylene thioglycol; ethylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripenta Polyhydric alcohols such as erythritol and sorbitol; hydroxyl group esterified with thioglycolic acid or 3-mercaptopropionic acid, 1,4-dihydronaphthalene , 1,4,5,8-tetrahydronaphthalene, beta-terpinene, terpinolene, 1,4-cyclohexadiene, and the like hydrogen sulfide. These may be used alone or in combination of two or more.

  The amount of chain transfer agent is not particularly limited because it varies depending on the type of chain transfer agent to be used. For example, when using a mercaptan, the raw material monomer is 100 mass. It is preferable that it is 0.01-3 mass parts with respect to a part, and it is more preferable that it is 0.05-1 mass part. A use amount within this range is preferable because it does not impair the mechanical properties of the polymer and maintains good thermal stability. When two or more kinds of chain transfer agents are used in combination, the total amount used may be within this range.

  In the present invention, the polymer polymerization method may be bulk polymerization without using a solvent or solution polymerization using a solvent, but bulk polymerization is particularly preferable.

  When the polymerization is carried out by the continuous solution polymerization method, the polymerization is carried out in the same manner as the continuous bulk polymerization method except that a solvent is used for the polymerization reaction. The solvent used for the polymerization reaction is appropriately set according to the raw material monomer of the continuous solution polymerization reaction and is not particularly limited. For example, toluene, xylene, ethylbenzene, methylisobutyl Examples include ketone, methyl alcohol, ethyl alcohol, octane, decane, cyclohexane, decalin, butyl acetate, and pentyl acetate. Of these, toluene, methanol, ethylbenzene, and butyl acetate are preferable. The solvent may be added to one or both of the initiator composition and the monomer composition, or may be directly supplied to the polymerization reaction tank 10. Although the ratio of a solvent is not specifically limited, 5-30 mass% of the whole raw material mixture is preferable, and 1-20 mass% is more preferable.

  In the polymerization reaction apparatus described above and the method for producing a polymer using the same, it is possible to sufficiently suppress the adhesion of the raw material monomer or the polymer thereof in the vicinity of the shaft seal bearing portion of the polymerization reaction apparatus. In addition, the polymer can be continuously produced over a long period without causing problems such as poor rotation of the stirring blade.

  The above-described polymerization reaction apparatus and the method for producing a polymer using the same can be suitably used for producing a (meth) acrylic polymer among polymers, and in particular, methyl (meth) acrylate as a main component. It can use suitably for manufacture of the (meth) acrylic-type polymer obtained by superposing | polymerizing the monomer mixture to perform.

  A polymer such as a (meth) acrylic polymer obtained by the above method can be suitably used in many fields such as lighting, a signboard, and a vehicle because excellent transparency and weather resistance are obtained. In particular, (meth) acrylic polymers are used for optical devices such as optical disk substrate materials, Fresnel lenses, lenticular lenses, light guide plates used in backlight systems for liquid crystal displays, diffusion plates, and protective front plates for liquid crystal displays. It can be suitably used for vehicle members such as materials, tail lamp covers, head lamp covers, visors, and meter panels.

  DESCRIPTION OF SYMBOLS 10 ... Polymerization reaction tank, 12 ... Raw material supply port, 14 ... Polymer composition discharge port, 16 ... Jacket, 20 ... Shaft, 22 ... Stirrer blade, 30 ... Shaft seal bearing part, 32 ... Shaft seal part (A), 34 ... Space part, 36 ... Liquid inlet, 38 ... Shaft seal part (B), 40 ... Shaft seal part, 100 ... Polymerization reactor, 101 ... Initiator preparation tank, 102 ... Monomer preparation tank.

Claims (4)

A polymerization reaction tank for performing a polymerization reaction of a raw material mixture containing monomers;
Stirring blades attached to a rotatable shaft for stirring the raw material mixture in the polymerization reaction tank;
A shaft seal bearing for supporting the shaft;
A polymerization reaction apparatus comprising:
The shaft seal bearing portion is provided between the shaft seal portion (A), a gap formed between the shaft seal portion (A) and the polymerization reaction tank, and between the gap portion and the polymerization reaction tank. The shaft seal portion (B), and the liquid that is introduced from the liquid introduction port, including a shaft seal portion that includes a liquid introduction port that introduces a liquid containing a polymerization inhibitor into the gap portion. Is configured to be discharged from the gap into the polymerization reaction tank ,
A polymerization reaction apparatus in which the shaft seal portion (B) is formed by a lip seal .   The polymerization reaction apparatus according to claim 1, wherein the shaft seal portion (A) is formed by a mechanical seal. A method for producing a polymer using the polymerization reaction apparatus according to claim 1 or 2 ,
A step of continuously supplying the raw material mixture containing the monomer into the polymerization reaction tank and performing a polymerization reaction while introducing the liquid containing the polymerization inhibitor into the gap from the liquid inlet. The manufacturing method of the polymer which has these. The method for producing a polymer according to claim 3 , wherein the liquid is a liquid obtained by dissolving the polymerization inhibitor in the monomer.

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