WO2015137103A1 - Method for producing polymer - Google Patents

Abstract

A method for producing a polymer, which comprises a ring-opening polymerization step for ring-opening polymerizing a ring-opening polymerizable monomer by bringing a starting material that contains the ring-opening polymerizable monomer into contact with a compressed fluid. An organic catalyst containing no metal atoms and a catalyst containing metal atoms are used in the ring-opening polymerization step.

Description

Polymer production method

The present invention relates to a polymer production method for producing a polymer by ring-opening polymerization of a ring-opening polymerizable monomer.

Conventionally, a method for producing a polymer by ring-opening polymerization of a ring-opening polymerizable monomer using a metal catalyst is known. For example, a method for producing polylactic acid by reacting a polymerization raw material mainly containing lactide as a ring-opening polymerization monomer in a molten state to produce polylactic acid is disclosed (for example, see Patent Document 1). According to the disclosed method, tin octylate is used as the metal catalyst, the reaction temperature is set to 195 ° C., and lactide is reacted and polymerized in a molten state.

However, when polylactic acid is produced by this production method, more than 2% by weight of lactide remains in the product. This is because in a ring-opening polymerization reaction system such as lactide, an equilibrium relationship between the ring-opening polymerizable monomer and the polymer is established, and the ring-opening polymerizable monomer is subjected to ring-opening polymerization at a high temperature such as the above reaction temperature. This is because a ring-opening polymerizable monomer is easily generated by a depolymerization reaction. Residual lactide functions as a hydrolysis catalyst for the product or reduces heat resistance.

As a method for ring-opening polymerization of the ring-opening polymerizable monomer at a low temperature, for example, a method of ring-opening polymerization of the ring-opening polymerizable monomer using a compressed gas solvent of hydrochlorofluorocarbon (HCFC-22) is disclosed. (For example, refer to Patent Document 2). According to the disclosed method, polylactide is obtained by using tin octoate as a catalyst, carrying out a polymerization at a reaction temperature of 100 ° C. and a pressure of 270 bar in a high pressure reactor for 2 hours.

However, when polylactide is produced by this production method, a large amount of catalyst tin octoate remains in the product. This is because the catalyst contains metal atoms and is not easily removed from the product. Residual tin octoate reduces the heat resistance and safety of the product.

As a method for polymerizing lactide using an organic catalyst containing no metal atom, for example, supercritical carbon dioxide is used as a solvent, and 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) is used as a catalyst. Has disclosed a method for ring-opening polymerization of the ring-opening polymerizable monomer by using (see, for example, Patent Document 3).

However, in this method, only a polymer having a number average molecular weight of about 20,000 was obtained, which was not satisfactory in practical use, and there was room for improvement.

Further, depending on the reaction conditions such as reaction temperature and reaction time, the type of catalyst, and the amount of catalyst used, there arises a problem that the polymer is colored.
Therefore, it has been desired to obtain a polymer that is not colored such as yellowing.

JP-A-8-259676 JP 2004-277698 A Japanese Patent No. 5182439

This invention makes it a subject to solve the said various problems in the past and to achieve the following objectives. That is, according to the present invention, a monomer residual ratio is small, a sufficiently high molecular weight polymer can be obtained even at a low temperature for a short time, and the metal atom content can be reduced by reducing the amount of catalyst used. And it aims at providing the manufacturing method of the polymer which can obtain the polymer without coloring.

Means for solving the problems are as follows. That is, the polymer production method of the present invention includes a ring-opening polymerization step of bringing a ring-opening polymerizable monomer into contact with a raw material containing a ring-opening polymerizable monomer and a compressive fluid, and ring-opening polymerization of the ring-opening polymerizable monomer.
In the ring-opening polymerization step, an organic catalyst containing no metal atom and a catalyst containing a metal atom are used.

According to the present invention, it is possible to solve the conventional problems and achieve the object, and to obtain a polymer having a sufficiently high molecular weight even with a low monomer residual rate and a low temperature, short time reaction. Further, it is possible to provide a method for producing a polymer that can reduce the content of metal atoms by reducing the amount of the catalyst used and obtain a polymer without coloring.

FIG. 1 is a general phase diagram showing the state of a substance with respect to temperature and pressure. FIG. 2 is a phase diagram for defining the range of the compressible fluid in the present embodiment. FIG. 3 is a system diagram showing an example of the polymerization process. FIG. 4 is a system diagram showing an example of the polymerization process. FIG. 5 is a system diagram showing an example of the polymerization process. FIG. 6A is a schematic diagram illustrating an example of a complex production system. FIG. 6B is a schematic diagram illustrating an example of a complex production system. FIG. 7 is a schematic diagram showing an example of a complex production system.

(Method for producing polymer)
The method for producing a polymer of the present invention includes at least a ring-opening polymerization step, and includes other steps as necessary.

<Ring-opening polymerization process>
The ring-opening polymerization step is a step of bringing the ring-opening polymerizable monomer into ring-opening polymerization by bringing a raw material containing the ring-opening polymerizable monomer into contact with a compressive fluid.
In the ring-opening polymerization step, the ring-opening polymerizable monomer is subjected to ring-opening polymerization using an organic catalyst containing no metal atom and a catalyst containing a metal atom.

As the catalyst, an organic catalyst that does not contain the metal atom and a catalyst that contains the metal atom are used. However, in order to obtain a higher quality polymer, research is being conducted to reduce the amount of catalyst used. In the situation, it is extremely rare to use both catalysts.
However, the present inventors in the ring-opening polymerization step of bringing the ring-opening polymerizable monomer into contact with the raw material containing the ring-opening polymerizable monomer and melting the ring-opening polymerizable monomer to perform ring-opening polymerization, When the organic catalyst containing no metal atom and the catalyst containing the metal atom are used in combination, the amount of use of both catalysts can be extremely suppressed, and even when these are added together, several steps from the amount of normal catalyst used. It has been found that a polymer having a sufficiently high molecular weight can be produced in a short time with a small amount.
Although the reason is not clear, when performing the ring-opening polymerization by melting the ring-opening polymerizable monomer, when both catalysts are used, the synergistic effect of the organic catalyst not containing the metal atom results in the catalyst containing the metal atom. It is speculated that this may be due to increased activity.
Further, in the ring-opening polymerization step, a treatment for removing at least one of the organic catalyst containing no metal atom and the catalyst containing the metal atom may be performed. Can be obtained.

<< Raw materials >>
In the present invention, the raw material refers to a material from which a polymer is produced and is a material constituting a polymer component. The raw material includes the ring-opening polymerizable monomer and, if necessary, polymerization initiation. Contains additives and additives.

-Ring-opening polymerizable monomer-
There is no restriction | limiting in particular as said ring-opening polymerizable monomer, Although it can select suitably according to the objective, What has an ester bond in a ring is preferable. Examples of such ring-opening polymerizable monomers include cyclic esters, cyclic carbonates, and cyclic amides.

There is no restriction | limiting in particular as said cyclic ester, Although it can select suitably according to the objective, The cyclic | annular form obtained by carrying out dehydration condensation of the L-form and / or D-form of the compound represented by following General formula (1) Dimers are preferred.
R—C * —H (—OH) (— COOH) General formula (1)
In the general formula (I), R represents an alkyl group having 1 to 10 carbon atoms, and “C *” represents an asymmetric carbon.

Examples of the compound represented by the general formula (1) include an enantiomer of lactic acid, an enantiomer of 2-hydroxybutanoic acid, an enantiomer of 2-hydroxypentanoic acid, and an enantiomer of 2-hydroxyhexanoic acid. , 2-hydroxyheptanoic acid enantiomer, 2-hydroxyoctanoic acid enantiomer, 2-hydroxynonanoic acid enantiomer, 2-hydroxydecanoic acid enantiomer, 2-hydroxyundecanoic acid enantiomer And enantiomers of 2-hydroxydodecanoic acid. Among these, enantiomers of lactic acid are particularly preferable from the viewpoint of reactivity or availability.
These cyclic dimers can be used alone or in admixture of several kinds.

In addition, examples of the cyclic ester include aliphatic lactones. Examples of the aliphatic lactone include β-propiolactone, β-butyrolactone, γ-butyrolactone, γ-hexanolactone, γ-octanolactone, δ eta-valerolactone, δ-hexalanolactone, δ- Examples include octanolactone, ε-caprolactone, δ-dodecanolactone, α-methyl-γ-butyrolactone, β-methyl-δ-valerolactone, glycolide, lactide, and p-dioxanone. Among these, ε-caprolactone is particularly preferable from the viewpoints of reactivity and availability.

The cyclic carbonate is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include ethylene carbonate and propylene carbonate.

The cyclic amide is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include ε-caprolactam and lauryl lactam.
These ring-opening polymerizable monomers may be used alone or in combination of two or more.

-Polymerization initiator-
The raw material may contain a polymerization initiator (hereinafter also referred to as an initiator) as necessary. The polymerization initiator is not particularly limited as long as it is an initiator that gives a branched structure to the polymer product, and can be appropriately selected according to the purpose. For example, any of monoalcohol, dialcohol, and polyhydric alcohol can be used. It may be either saturated alcohol or unsaturated alcohol.

Examples of the monoalcohol include methanol, ethanol, propanol, butanol, pentanol, hexanol, heptanol, nonanol, decanol, lauryl alcohol, myristyl alcohol, cetyl alcohol, and stearyl alcohol.
Examples of the dialcohol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexanediol, nonanediol, tetramethylene glycol, and polyethylene glycol. Etc.
Examples of the polyhydric alcohol include glycerol, sorbitol, xylitol, ribitol, erythritol, triethanolamine, and the like.
Examples of the unsaturated alcohol include methyl lactate and ethyl lactate.

Further, a polymer having an alcohol residue at the terminal, such as polycaprolactone diol or polytetramethylene glycol, may be used as the polymerization initiator. Thereby, a diblock or triblock copolymer is synthesized.

The amount of the polymerization initiator used is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 0.05 mol% or more and 5 mol% or less with respect to the ring-opening polymerizable monomer. In order to prevent the polymerization from starting unevenly, it is desirable that the initiator is well mixed with the monomer in advance before the monomer contacts the polymerization catalyst.

-Additive-
You may make the said raw material contain an additive as needed. Examples of the additive include surfactants, antioxidants, stabilizers, antifogging agents, ultraviolet absorbers, pigments, colorants, inorganic particles, various fillers, thermal stabilizers, flame retardants, crystal nucleating agents, and charging agents. Inhibitors, surface wetting improvers, incineration aids, lubricants, natural products, mold release agents, plasticizers, and the like.
There is no restriction | limiting in particular as the usage-amount of the said additive, Although it can select suitably according to the objective and the kind of additive, 0 to 5 mass parts is preferable with respect to 100 mass parts of polymer compositions.

As the surfactant, those that melt into the compressive fluid and have affinity for both the compressive fluid and the ring-opening polymerizable monomer are preferably used. By using such a surfactant, the polymerization reaction can be progressed uniformly, and a product having a narrow molecular weight distribution can be obtained, and effects such as easy to obtain a particulate polymer can be expected. When using a surfactant, it may be added to the compressive fluid or to the ring-opening polymerizable monomer. For example, when carbon dioxide is used as the compressive fluid, a surfactant having a parent carbon dioxide group and a parent monomer group in the molecule is used. Examples of such surfactants include fluorine-based surfactants and silicon-based surfactants.

As the stabilizer, for example, epoxidized soybean oil, carbodiimide and the like are used. As the antioxidant, for example, 2,6-di-t-butyl-4-methylphenol, butylhydroxyanisole and the like are used. Examples of the antifogging agent include glycerin fatty acid ester and monostearyl citrate. As the filler, for example, an ultraviolet absorber, a heat stabilizer, a flame retardant, an internal mold release agent, clay having an effect as a crystal nucleating agent, talc, silica, or the like is used. As the pigment, for example, titanium oxide, carbon black, ultramarine blue and the like are used.

<< Compressive fluid >>
The compressive fluid will be described with reference to FIGS. 1 and 2. FIG. 1 is a phase diagram showing the state of a substance with respect to temperature and pressure. FIG. 2 is a phase diagram for defining the range of the compressible fluid in the present embodiment.
The compressible fluid means a fluid in a state existing in one of the regions (1), (2), and (3) shown in FIG. 2 in the phase diagram shown in FIG. .

In such a region, it is known that the substance has a very high density and behaves differently from that at normal temperature and pressure. In addition, when a substance exists in the area | region of (1), it becomes a supercritical fluid. A supercritical fluid is a fluid that exists as a non-condensable high-density fluid in a temperature and pressure region that exceeds the limit (critical point) at which gas and liquid can coexist, and does not condense even when compressed. Further, when the substance is present in the region (2), it becomes a liquid, but in this embodiment, it is obtained by compressing a substance that is in a gaseous state at normal temperature (25 ° C.) and normal pressure (1 atm). Represents liquefied gas. Further, when the substance is present in the region (3), it is in a gaseous state, but in the present embodiment, it represents a high pressure gas whose pressure is 1/2 (1/2 Pc) or more of the critical pressure (Pc).

Examples of the substance constituting the compressive fluid include carbon monoxide, carbon dioxide, dinitrogen monoxide, nitrogen, methane, ethane, propane, 2,3-dimethylbutane, and ethylene. Among these, carbon dioxide is preferable in that it has a critical pressure of about 7.4 MPa and a critical temperature of about 31 ° C., can easily create a supercritical state, and is nonflammable and easy to handle. These compressive fluids may be used alone or in combination of two or more.

Since carbon dioxide reacts with basic and nucleophilic substances, it has traditionally been considered that it cannot be applied to living anion polymerization when supercritical carbon dioxide is used as a solvent ("Latest application of supercritical fluids" Technology ", page 173, March 15, 2004, issued by NTS Corporation). However, the present inventors overturned the conventional knowledge, and even in supercritical carbon dioxide, the organic catalyst having basicity and nucleophilicity is stably coordinated to the ring-opening monomer, and the ring-opening monomer is allowed to open the ring. The inventors have found that the polymerization reaction proceeds quantitatively in a short time, and as a result, the polymerization reaction proceeds in a living manner. Living as used herein means that the reaction proceeds quantitatively without side reactions such as transfer reaction and termination reaction, and the molecular weight distribution of the obtained polymer is relatively narrow and monodisperse.

<< Organic catalyst not containing metal atoms >>
The organic catalyst not containing a metal atom (hereinafter also referred to as an organic catalyst) is not particularly limited and may be appropriately selected depending on the purpose. For example, the organic catalyst does not contain a metal atom and What contributes to the ring-opening polymerization reaction and forms an active intermediate with the ring-opening polymerizable monomer and then desorbs and regenerates by reaction with an alcohol is preferable.

For example, when polymerizing a ring-opening polymerizable monomer having an ester bond, the organic catalyst is preferably a (nucleophilic) compound that functions as a basic nucleophile, and more preferably a compound containing a nitrogen atom. A cyclic compound containing a nitrogen atom is particularly preferred. There is no restriction | limiting in particular as said compounds, According to the objective, it can select suitably, For example, cyclic | annular monoamine, cyclic diamine (For example, cyclic diamine compound etc. which have amidine skeleton), cyclic triamine which has guanidine skeleton. Examples thereof include a compound, a heterocyclic aromatic organic compound containing a nitrogen atom, and N-heterocyclic carbene. A cationic organic catalyst is used for ring-opening polymerization. In this case, hydrogen is extracted from the polymer main chain (back-biting), so that the molecular weight distribution becomes wide and it is difficult to obtain a high molecular weight product.

Examples of the cyclic monoamine include quinuclidine.
Examples of the cyclic diamine include 1,4-diazabicyclo- [2.2.2] octane (DABCO), 1,5-diazabicyclo (4,3,0) -5-nonene.
Examples of the cyclic diamine compound having an amidine skeleton include 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) and diazabicyclononene.
Examples of the cyclic triamine compound having a guanidine skeleton include 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD), diphenylguanidine (DPG), and the like.
Examples of the heterocyclic aromatic organic compound containing a nitrogen atom include N, N-dimethyl-4-aminopyridine (DMAP), 4-pyrrolidinopyridine (PPY), pyrocholine, imidazole, pyrimidine, purine and the like. Can be mentioned.
Examples of the N-heterocyclic carbene include 1,3-di-tert-butylimidazol-2-ylidene (ITBU).
Among these, DABCO, DBU, DPG, TBD, DMAP, PPY, and ITBU are preferable because they are less affected by steric hindrance and have high nucleophilicity or have a boiling point that can be removed under reduced pressure.

Among these organic catalysts, for example, DBU is liquid at room temperature and has a boiling point. When such an organic catalyst is selected, the organic catalyst can be almost quantitatively removed from the polymer product by subjecting the obtained polymer product to a reduced pressure treatment. In addition, the kind of organic catalyst and the presence or absence of a removal process are determined according to the use purpose of a product, etc.

The type and amount of the organic catalyst vary depending on the combination of the compressive fluid and the ring-opening polymerizable monomer, and thus cannot be specified unconditionally. However, in terms of stability and coloring, the amount of the organic catalyst used is 45 ppm to 500 ppm is preferable, 45 ppm to 500 ppm is more preferable, and 50 ppm to 200 ppm is particularly preferable with respect to 1 part by mass of the ring-opening polymerizable monomer.

<< Catalyst Containing Metal Atom >>
The catalyst containing the metal atom (hereinafter also referred to as a metal catalyst) is not particularly limited and may be appropriately selected depending on the intended purpose. For example, a tin compound, an aluminum compound, a titanium compound, a zirconium compound Examples thereof include compounds and antimony compounds.
Examples of the tin compound include tin octylate, tin dibutyrate, and di (2-ethylhexanoic acid) tin.
Examples of the aluminum compound include aluminum acetylacetonate and aluminum acetate.
Examples of the titanium compound include tetraisopropyl titanate and tetrabutyl titanate.
Examples of the zirconium-based compound include zirconium isoprooxide.
Examples of the antimony compound include antimony trioxide.

The type and amount of the metal catalyst vary depending on the combination of the compressive fluid and the ring-opening polymerizable monomer, and thus cannot be specified unconditionally. However, in terms of stability and coloring, the amount of the metal catalyst used depends on the amount of the metal catalyst. 1 ppm to 200 ppm is preferable, 50 ppm to 200 ppm is more preferable, and 50 ppm to 100 ppm is particularly preferable with respect to 1 part by mass of the ring polymerizable monomer.

The combination of the organic catalyst and the metal catalyst is appropriately selected according to the purpose. A plurality of the organic catalyst and the metal catalyst may be mixed.
Moreover, it is preferable that at least one of the organic catalyst and the metal catalyst has basicity. The reactivity may be increased by having basicity.

The mass ratio of the amount used of the organic catalyst and the metal catalyst (organic catalyst: metal catalyst) is appropriately selected depending on the nature of the catalyst to be mixed, but in terms of safety, 50:50 to 99: 1 70:30 to 99: 1 are more preferable. The total amount used of the organic catalyst and the metal catalyst cannot be generally specified because it varies depending on the compressive fluid used in the production, the ring-opening polymerizable monomer, or the combination of catalysts to be mixed. In terms of coloring, 50 ppm to 500 ppm is preferable with respect to 1 part by mass of the ring-opening polymerizable monomer, and 50 ppm to 200 ppm is more preferable.

<< Polymerization reactor >>
Subsequently, an example of a polymerization reaction apparatus used in the method for producing a polymer of the present invention will be described with reference to FIGS. 3 to 5 are system diagrams showing an example of the polymerization process.

-Continuous polymerization reactor-
First, the continuous polymerization reaction apparatus 100 shown in FIG. 3 will be described. In the system diagram of FIG. 3, the polymerization reaction apparatus 100 includes a supply unit 100 a that supplies a raw material such as a ring-opening polymerizable monomer and a compressive fluid, and a continuous polymerization that polymerizes the ring-opening polymerizable monomer supplied by the supply unit 100 a. And a polymerization reaction apparatus main body 100b as an example of the apparatus. The supply unit 100a has a tank (1, 3, 5, 7, 11), a measuring feeder (2, 4), and a measuring pump (6, 8, 12). The polymerization reaction device main body 100b includes a melt mixing device 9, a liquid feed pump 10, a reaction vessel 13, a metering pump 14, and the other end of the polymerization reaction device main body 100b provided at one end of the polymerization reaction device main body 100b. And an extrusion die 15 provided on the surface. In the present invention, “melting” means a state in which a raw material or a produced polymer comes into contact with a compressive fluid and is plasticized or liquefied while swelling. In addition, the “melt mixing device” is a device that melts raw materials by bringing the compressive fluid into contact with the raw materials.

The tank 1 of the supply unit 100a stores a ring-opening polymerizable monomer. The ring-opening polymerizable monomer to be stored may be a powder or a molten state. The tank 3 stores a solid (powder or granular) one of the initiator and the additive. The tank 5 stores a liquid one of the initiator and the additive. The tank 7 stores a compressible fluid. In addition, the tank 7 may store a gas (gas) or a solid that becomes a compressible fluid in a process of being supplied to the melt mixing device 9 or heated or pressurized in the melt mixing device 9. . In this case, the gas or solid stored in the tank 7 is heated or pressurized, and the state of (1), (2), or (3) in the phase diagram of FIG. Become.

The measuring feeder 2 measures the ring-opening polymerizable monomer stored in the tank 1 and continuously supplies it to the melt mixing device 9. The weighing feeder 4 measures the solid stored in the tank 3 and continuously supplies it to the melt mixing device 9. The metering pump 6 measures the liquid stored in the tank 5 and continuously supplies it to the melt mixing device 9. The metering pump 8 continuously supplies the compressive fluid stored in the tank 7 to the melt mixing device 9 at a constant pressure and flow rate. In addition, in this embodiment, supplying continuously is a concept with respect to the method of supplying for every batch, and means supplying so that the polymer which carried out ring-opening polymerization may be obtained continuously. In other words, each material may be supplied intermittently or intermittently as long as the ring-opened polymer is continuously obtained. In addition, when both the initiator and the additive are solid, the polymerization reaction apparatus 100 may not include the tank 5 and the metering pump 6. Similarly, when both the initiator and the additive are liquid, the polymerization reaction apparatus 100 may not include the tank 3 and the metering feeder 4.

In this embodiment, each apparatus of the polymerization reaction apparatus main body 100b is connected as shown in FIG. 3 by a pressure-resistant piping 30 that transports raw materials, a compressive fluid, or a generated polymer. In addition, each of the melt mixing device 9, the liquid feeding pump 10, and the reaction vessel 13 of the polymerization reaction device has a tubular member through which the above raw materials and the like pass.

The melt mixing device 9 of the polymerization reaction device main body 100b includes raw materials such as ring-opening polymerizable monomers, initiators and additives supplied from the tanks (1, 3, 5), and a compressive fluid supplied from the tank 7. Is a device having a pressure-resistant container for melting the raw materials. In this embodiment, since the raw material such as the ring-opening polymerizable monomer and the compressive fluid can be continuously contacted at a constant concentration ratio, the raw material can be efficiently melted into the compressive fluid. it can.

The shape of the container of the melt mixing device 9 may be a tank type or a cylindrical type, but a cylindrical type in which raw materials are supplied from one end and the mixture is taken out from the other end is preferable. In the container of the melt mixing device 9, an inlet 9 a for introducing the compressive fluid supplied from the tank 7 by the metering pump 8 and an inlet for introducing the ring-opening polymerizable monomer supplied from the tank 1 by the metering feeder 2 are introduced. 9b, an inlet 9c for introducing the powder supplied from the tank 3 by the measuring feeder 4, and an inlet 9d for introducing the liquid supplied from the tank 5 by the measuring pump 6 are provided. In this embodiment, each inlet (9a, 9b, 9c, 9d) is comprised by the coupling which connects the container of the melt mixing apparatus 9, and each piping which conveys each raw material or compressive fluid. This joint is not particularly limited, and known joints such as reducers, couplings, Y-type joints, T-type joints, and outlets are used. Moreover, the melt mixing apparatus 9 has a heater for heating each supplied raw material and compressive fluid. Furthermore, the melt mixing device 9 may have a stirring device for stirring raw materials, compressive fluids, and the like. When the melt mixing device 9 has a stirrer, the stirrer includes a uniaxial screw, a biaxial screw meshing with each other, a biaxial mixer having a large number of meshing elements meshing with or overlapping each other, and a helical stirring element meshing with each other. A kneader, a static mixer or the like having the above is preferably used. In particular, a biaxial or multiaxial agitation device that meshes with each other is preferable because there is little adhesion of reactants to the agitation device or the container and there is a self-cleaning action. In the case where the melt mixing device 9 does not have a stirrer, a pressure resistant pipe is preferably used as the melt mixing device 9. In addition, when the melt mixing apparatus 9 does not have a stirring apparatus, in order to mix each material in the melt mixing apparatus 9 reliably, the ring-opening polymerizable monomer supplied to the melt mixing apparatus 9 is in a molten state. It is preferable.

The liquid feed pump 10 sends each raw material melted by the melt mixing device 9 to the reaction vessel 13. The tank 11 stores a catalyst. The metering pump 12 measures the catalyst stored in the tank 11 and supplies it to the reaction vessel 13. FIG. 3 shows an example in which one tank 11 is used. However, in this embodiment, two types of catalyst, ie, an organic catalyst and a metal catalyst are used. Therefore, after using an organic catalyst in the tank 11, the metal catalyst is inserted again. Alternatively, if a metal catalyst is used and then the organic catalyst is reinserted, the number of tanks 11 may be one. However, when both catalysts are used simultaneously or when both catalysts are stored in a tank, two or more tanks 11 can be used. In that case, piping for supplying the catalyst to the reaction vessel 13 via the metering pump 12 and the inlet 13b is provided for each number of tanks 11.

The reaction container 13 is a pressure-resistant container for mixing the melted raw materials fed by the liquid feed pump 10 and the catalyst supplied by the metering pump 12 to cause the ring-opening polymerizable monomer to undergo ring-opening polymerization. It is. The shape of the reaction vessel 13 may be a tank type or a cylindrical type, but a cylindrical type with little dead space is preferable.

The reaction vessel 13 has an introduction port 13a for introducing each material mixed by the melt mixing device 9 into the vessel, and an introduction port 13b for introducing the catalyst supplied from the tank 11 by the metering pump 12 into the vessel. Is provided. In this embodiment, each inlet (13a, 13b) is comprised by the coupling which connects the reaction container 13 and each piping which conveys each raw material. This joint is not particularly limited, and known joints such as reducers, couplings, Y-type joints, T-type joints, and outlets are used. The reaction vessel 13 may be provided with a gas outlet for removing the evaporated material. The reaction vessel 13 has a heater for heating the fed raw material.
Furthermore, the reaction vessel 13 may have a stirring device that stirs the raw materials, the compressive fluid, and the like. When the reaction vessel 13 has a stirrer, the polymer particles can be prevented from settling due to the difference in density between the raw material and the produced polymer, so that the polymerization reaction can proceed more uniformly and quantitatively. As a stirring device for the reaction vessel 13, a twin shaft having a screw which meshes with each other, a stirring element such as a 2-flight (oval) or a 3-flight (triangular shape), a disc or a multi-leaf type (clover-shaped) stirring blade. Or the thing of a multi-axis is preferable from a viewpoint of self-cleaning. In the case where the raw material containing the catalyst is sufficiently mixed in advance, a static mixer that performs multi-stage division and combination (merging) of the flow with a guide device can also be applied to the stirring device. As static mixers, those disclosed in Japanese Patent Publication Nos. 47-15526, 47-15527, 47-15528, 47-15533, etc. (multilayer mixer), and disclosed in JP-A-47-33166. And the like (Kenix type) and similar mixing devices without moving parts. When the reaction vessel 13 does not have a stirrer, pressure-resistant piping is preferably used as the reaction vessel 13.

FIG. 3 shows an example in which the number of reaction vessels 13 is one, but two or more reaction vessels 13 can also be used. When a plurality of reaction vessels 13 are used, the reaction (polymerization) conditions for each reaction vessel 13, that is, temperature, catalyst concentration, pressure, average residence time, stirring speed, etc. may be the same. It is preferable to select the optimum conditions. In order to increase the reaction time and complicate the apparatus, it is not a good idea to combine too many containers in multiple stages, and the number of stages is preferably 1 or more and 4 or less, particularly preferably 1 or more and 3 or less.

Generally, when polymerization is performed with only one reaction vessel, the degree of polymerization of the polymer obtained and the amount of residual monomer are unstable and easily fluctuate, and are not suitable for industrial production. This is considered to be caused by instability due to mixing of a polymerization raw material having a melt viscosity of several poise to several tens of poise and a polymerized polymer having a melt viscosity of about 1,000 poise in the same container. . On the other hand, in this embodiment, since the raw material and the produced polymer are melted (liquefied), it becomes possible to reduce the difference in viscosity in the reaction vessel 13 (also referred to as a polymerization system), so that the conventional polymerization Even if the number of stages is reduced as compared with the reactor, the polymer can be produced stably.

The metering pump 14 sends the polymer product P polymerized in the reaction vessel 13 out of the reaction vessel 13 from an extrusion die 15 as an example of a polymer discharge port. In addition, the polymer product P can be sent out from the reaction vessel 13 without using the metering pump 14 by utilizing the pressure difference between the inside and outside of the reaction vessel 13. In this case, in order to adjust the pressure in the reaction vessel 13 and the delivery amount of the polymer product P, the pressure adjusting valve 16 can be used as shown in FIG.

-Batch polymerization reactor-
Next, the batch type polymerization reaction apparatus 400 shown in FIG. 5 will be described. In the system diagram of FIG. 5, the polymerization reaction apparatus 400 includes a tank 407, a metering pump 408, an addition pot 411, a reaction vessel 413, and valves (421, 422, 423, 424, 425). . Each of the above devices is connected by a pressure resistant pipe 430 as shown in FIG. The pipe 430 is provided with joints (430a, 430b).

The tank 407 stores a compressible fluid. The tank 407 may store a gas (gas) or solid that is heated and pressurized in the supply path supplied to the reaction vessel 413 or the reaction vessel 413 to become a compressible fluid. In this case, the gas or solid stored in the tank 407 is heated or pressurized to be in the state (1), (2), or (3) in the phase diagram of FIG. .

The metering pump 408 supplies the compressive fluid stored in the tank 407 to the reaction vessel 413 at a constant pressure and flow rate.
The addition pot 411 stores a catalyst added to the raw material in the reaction vessel 413. The valves (421, 422, 423, 424) open and close each, thereby supplying a compressive fluid stored in the tank 407 to the reaction vessel 413 via the addition pot 411, and the addition pot 411. The route for supplying to the reaction vessel 413 without switching through is switched.
FIG. 5 shows an example in which the addition pot 411 is one. However, in this embodiment, since two types of catalyst, an organic catalyst and a metal catalyst, are used, if an organic catalyst is put in the addition pot 411, then a metal catalyst is added. If the metal catalyst is reinserted or the metal catalyst is used and then the organic catalyst is reinserted, the number of addition pots 411 may be one. However, when both catalysts are used simultaneously or when both catalysts are stored in a tank, two or more addition pots 411 can be used. In that case, piping for supplying the catalyst to the reactor 413 is provided for each number of the addition pots 411 through the joints (430a, 430b) and the valves (423, 424).

The reaction vessel 413 contains a ring-opening polymerizable monomer and an initiator in advance before starting the polymerization. As a result, the reaction vessel 413 is brought into contact with the ring-opening polymerizable monomer and initiator stored in advance, the compressive fluid supplied from the tank 407, and the catalyst supplied from the addition pot 411. It is a pressure-resistant container for ring-opening polymerization of a functional monomer. Note that the reaction vessel 413 may be provided with a gas outlet for removing evaporated substances. The reaction vessel 413 has a heater for heating the raw materials and the compressive fluid. Furthermore, the reaction vessel 413 includes a stirring device that stirs the raw materials and the compressive fluid. When the density difference between the raw material and the generated polymer occurs, the settling of the generated polymer can be suppressed by adding the stirring of the stirring device, so that the polymerization reaction can proceed more uniformly and quantitatively. The valve 425 is opened after the completion of the polymerization reaction to discharge the compressive fluid and the product (polymer) in the reaction vessel 413. The reaction vessel 413 may have a valve 432 for taking out the compressive fluid out of the reaction vessel in the middle of the polymerization process.

<< Continuous polymerization method and batch polymerization method >>
About the continuous polymerization method of the ring-opening polymerizable monomer in the present embodiment using the polymerization reactor 100, and the batch type polymerization method of the ring-opening polymerizable monomer in the present embodiment using the polymerization reactor 400, respectively. Will be described in detail.

-Continuous polymerization method-
First, a continuous polymerization method for ring-opening polymerizable monomers using the polymerization reaction apparatus 100 will be described. In the polymerization reaction apparatus 100, the raw material containing the ring-opening polymerizable monomer and the compressive fluid are continuously brought into contact with each other, and the ring-opening polymerizable monomer is subjected to ring-opening polymerization to continuously obtain a polymer.
First, each metering feeder (2, 4), the metering pump 6, and the metering pump 8 are operated, and the ring-opening polymerizable monomer, initiator, additive, compressive fluid in each tank (1, 3, 5, 7). Are continuously introduced into the container of the melt mixing device 9 from each inlet (9a, 9b, 9c, 9d). In addition, solid (powder or granular) raw materials may have lower measurement accuracy than liquid raw materials. In this case, the solid raw material may be previously melted and stored in the tank 5 in a liquid state, and introduced into the container of the melt mixing device 9 by the metering pump 6. The order in which each metering feeder (2, 4), metering pump 6 and metering pump 8 are operated is not particularly limited, but when the initial raw material is sent to the reaction vessel 13 without contacting the compressed fluid, it solidifies due to a decrease in temperature. Therefore, it is preferable to operate the metering pump 8 first.

Each feed rate of each raw material by the metering feeders (2, 4) and the metering pump 6 is adjusted to be a constant ratio based on a predetermined ratio of the ring-opening polymerizable monomer, the initiator, and the additive. The The total mass of raw materials supplied per unit time by the metering feeders (2, 4) and the metering pump 6 (raw material feed rate (feed amount), (g / min)) is the desired polymer properties and reaction time. It is adjusted based on etc. Similarly, the mass of the compressible fluid supplied per unit time by the metering pump 8 (supply rate of the compressible fluid (feed amount), (g / min)) is based on desired polymer physical properties, reaction time, and the like. Adjusted. The ratio of the feed rate of the raw material and the feed rate of the compressible fluid represented by the following inequality (hereinafter also referred to as feed ratio) is preferably 0.50 or more and less than 1.00, and is 0.65 or more and 0.99. Or less, more preferably 0.80 or more and 0.95 or less.

 

If the feed ratio is less than 0.5, the amount of the compressive fluid used is not economical, and the density of the ring-opening polymerizable monomer is lowered, so that the polymerization rate may decrease. Further, when the feed ratio is less than 0.5, the mass of the compressive fluid becomes larger than the mass of the raw material, so that the melt phase in which the ring-opening polymerizable monomer is melted and the ring-opening polymerizable monomer is in the compressive fluid The fluid phase dissolved in the coexistence may coexist and the reaction may not easily proceed.

By setting the feed ratio to 0.5 or more, when each raw material and the compressive fluid are sent to the reaction vessel 13, the reaction is performed in a state where the concentration of the raw material and the generated polymer (so-called solid content concentration) is high. proceed. The solid content concentration in the polymerization system at this time is the solid content concentration of the polymerization system when polymerizing by dissolving a small amount of ring-opening polymerizable monomer in an overwhelming amount of compressive fluid in the conventional production method. Are very different. In the production method of the present embodiment, the polymerization reaction proceeds efficiently and stably even in a polymerization system having a high solid content concentration. When the feed ratio exceeds 0.99, the ability of the compressive fluid to melt the ring-opening polymerizable monomer may be insufficient, and the target reaction may not proceed uniformly.

Since each raw material and compressive fluid are continuously introduced into the container of the melt mixing device 9, they are in continuous contact with each other. As a result, the raw materials such as the ring-opening polymerizable monomer, the initiator, and the additive are melted in the melt mixing device 9. When the melt mixing device 9 has a stirring device, the raw materials and the compressive fluid may be stirred. In order to prevent the introduced compressive fluid from turning into a gas, the temperature and pressure in the container of the reaction vessel 13 are controlled to a temperature and pressure at least above the triple point of the compressive fluid. This control is performed by adjusting the output of the heater of the melt mixing device 9 or the supply amount of the compressive fluid. In the present embodiment, the temperature at which the ring-opening polymerizable monomer is melted may be a temperature equal to or lower than the melting point at normal pressure of the ring-opening polymerizable monomer. This is considered to be due to the high pressure in the melt mixing device 9 in the presence of the compressive fluid, and the melting point of the ring-opening polymerizable monomer being lower than the melting point at normal pressure. For this reason, even when the amount of the compressive fluid with respect to the ring-opening polymerizable monomer is small, the ring-opening polymerizable monomer is melted in the melt mixing device 9.

The timing of applying heat and stirring to each raw material and compressive fluid may be adjusted by the melt mixing device 9 so that each raw material is efficiently melted. In this case, after bringing each raw material and the compressive fluid into contact, heat or stirring may be applied, or heat or stirring may be applied while bringing each raw material into contact with the compressive fluid. In order to melt more reliably, for example, the ring-opening polymerizable monomer and the compressive fluid may be brought into contact with each other after the ring-opening polymerizable monomer is previously melted by applying heat equal to or higher than the melting point. For example, in the case where the melt mixing device 9 is a biaxial mixing device, the above-described embodiments are arranged in an arrangement of screws, the arrangement of the inlets (9a, 9b, 9c, 9d), the temperature of the heater of the melt mixing device 9 This is realized by setting as appropriate.

In this embodiment, the additive is supplied to the melt mixing device 9 separately from the ring-opening polymerizable monomer, but the additive may be supplied together with the ring-opening polymerizable monomer. Moreover, you may supply an additive after a polymerization reaction. In this case, after taking out the polymer product obtained from the reaction vessel 13, the additive can be added while melt-kneading.

Each material melted by the melt mixing device 9 is fed by the feed pump 10 and supplied to the reaction vessel 13 from the inlet 13a. On the other hand, the catalyst in the tank 11 is measured by the metering pump 12 and supplied to the reaction vessel 13 through the introduction port 13b. In this embodiment, the catalyst is added after the raw material is melted in the compressive fluid because the catalyst can act at room temperature.
The catalyst may be added before or after contacting the ring-opening polymerizable monomer with the compressive fluid. The contact of the catalyst and the compressive fluid may be before or after the addition to the ring-opening polymerizable monomer.

Also, in this embodiment, two types of organic catalyst and metal catalyst are used. Even if the polymer intermediate is first produced using the organic catalyst and then the polymer product is produced using the metal catalyst, the metal catalyst is first produced. The catalyst may be used to produce a polymer intermediate followed by an organic catalyst to produce a polymer product, or simultaneously an organic catalyst and a metal catalyst to produce a polymer product. The order of addition of the catalyst is appropriately selected according to the purpose, but the raw material containing the ring-opening polymerizable monomer and the compressive fluid are brought into contact with each other in the presence of the organic catalyst not containing the metal atom. A method in which the ring-opening polymerizable monomer is subjected to ring-opening polymerization and then further polymerized in the presence of the metal atom-containing catalyst is more preferable from the viewpoint of improving the conversion rate.

The materials fed by the feed pump 10 and the catalyst supplied by the metering pump 12 are sufficiently stirred by the stirring device of the reaction vessel 13 as necessary, and heated to a predetermined temperature by the heater. Thereby, the ring-opening polymerizable monomer undergoes ring-opening polymerization in the presence of the catalyst in the reaction vessel 13 (polymerization step).

The lower limit of the temperature (polymerization reaction temperature) for ring-opening polymerization of the ring-opening polymerizable monomer is not particularly limited, but is preferably 40 ° C, more preferably 50 ° C, and particularly preferably 60 ° C. When the polymerization reaction temperature is less than 40 ° C., depending on the ring-opening polymerizable monomer species, it takes a long time to melt by the compressive fluid, the melting is insufficient, or the activity of the catalyst is lowered. As a result, the reaction rate tends to decrease during polymerization, and the polymerization reaction may not proceed quantitatively.

The upper limit of the polymerization reaction temperature is not particularly limited, but is 100 ° C. or 30 ° C. higher than the melting point of the ring-opening polymerizable monomer, whichever is higher. The upper limit of the polymerization reaction temperature is preferably 90 ° C. or the higher melting point of the ring-opening polymerizable monomer, and preferably 80 ° C. or 20 ° C. lower than the melting point of the ring-opening polymerizable monomer. Temperature is more preferred. When the polymerization reaction temperature exceeds 30 ° C. higher than the melting point of the ring-opening polymerizable monomer, the depolymerization reaction, which is the reverse reaction of the ring-opening polymerization, tends to occur in equilibrium, and the polymerization reaction is difficult to proceed quantitatively. When using a ring-opening monomer having a low melting point, such as a ring-opening polymerizable monomer that is liquid at room temperature, the polymerization reaction temperature may be 30 ° C. higher than the melting point in order to increase the activity of the catalyst. Even in this case, the polymerization reaction temperature is preferably 100 ° C. or lower. The polymerization reaction temperature is controlled by a heater provided in the reaction vessel 13 or heating from the outside of the reaction vessel 13. Moreover, when measuring polymerization reaction temperature, you may use the polymer product obtained by polymerization reaction.

In a conventional method for producing a polymer using supercritical carbon dioxide, since supercritical carbon dioxide has low polymer solubility, ring-opening polymerizable monomers were polymerized using a large amount of supercritical carbon dioxide. According to the polymerization method of the present embodiment, in the method for producing a polymer using a compressive fluid, the ring-opening polymerizable monomer is subjected to ring-opening polymerization at an unprecedented high concentration. In this case, the pressure in the reaction vessel 13 becomes high in the presence of the compressive fluid, and the glass transition temperature (Tg) of the produced polymer is lowered. As a result, the viscosity of the produced polymer is lowered, and the ring-opening polymerization reaction proceeds uniformly even when the concentration of the polymer product is high.

In the present embodiment, the polymerization reaction time (average residence time in the reaction vessel 13) is set according to the target molecular weight, but is usually preferably within 1 hour, more preferably within 45 minutes, and within 30 minutes. Is particularly preferred. According to the production method of the present embodiment, the polymerization reaction time can be set to 20 minutes or less. This is a short time that is unprecedented in the polymerization of ring-opening polymerizable monomers in a compressible fluid.

The pressure at the time of polymerization, that is, the pressure of the compressive fluid is such that the compressive fluid supplied from the tank 7 is a liquefied gas ((2) in the phase diagram of FIG. 2) or a high-pressure gas ((3) in the phase diagram of FIG. 2). The pressure that becomes the supercritical fluid ((1) in the phase diagram of FIG. 2) is preferable. By making the compressible fluid into a supercritical fluid state, melting of the ring-opening polymerizable monomer is promoted, and the polymerization reaction can be promoted uniformly and quantitatively. When carbon dioxide is used as the compressible fluid, the pressure is preferably 3.7 MPa or more, more preferably 5 MPa or more, and a critical pressure of 7.4 MPa or more, considering efficiency of the reaction, polymer conversion rate, and the like. Particularly preferred. Moreover, when using a carbon dioxide as a compressive fluid, it is preferable that the temperature is 25 degreeC or more for the same reason.

The water content in the reaction vessel 13 is preferably 4 mol% or less, more preferably 1 mol% or less, and particularly preferably 0.5 mol% or less with respect to the ring-opening polymerizable monomer. When the amount of water exceeds 4 mol%, the water itself contributes as an initiator, so that it may be difficult to control the molecular weight. In order to control the amount of water in the polymerization reaction system, an operation for removing water contained in the ring-opening polymerizable monomer and other raw materials may be added as a pretreatment as necessary.

The polymer product P that has completed the ring-opening polymerization reaction in the reaction vessel 13 is sent out of the reaction vessel 13 by the metering pump 14. The rate at which the metering pump 14 delivers the polymer product P is preferably constant in order to obtain a uniform polymerized product by operating at a constant pressure in the polymerization system filled with the compressive fluid. Therefore, the liquid feeding mechanism inside the reaction vessel 13 and the liquid feeding amount of the liquid feeding pump 10 are controlled so that the back pressure of the metering pump 14 is constant. Similarly, the feeding speed of the liquid feeding mechanism, the metering feeders (2, 4), and the metering pumps (6, 8) in the melt mixing device 9 are controlled so that the back pressure of the liquid pump 10 is constant. . The control method may be an ON-OFF type, that is, an intermittent feed type, but a continuous or step method in which the rotational speed of a pump or the like is gradually increased or decreased is often more preferable. In any case, a uniform polymer product can be stably obtained by such control.

-Batch polymerization method-
Next, a batch polymerization method for ring-opening polymerizable monomers using the polymerization reaction apparatus 400 will be described. In the polymerization reaction apparatus 400, a raw material containing a ring-opening polymerizable monomer and a compressive fluid are brought into contact with each other at a predetermined mixing ratio, and the ring-opening polymerizable monomer is subjected to ring-opening polymerization in the presence of a catalyst. In this case, first, the metering pump 408 is operated and the valves (421, 422) are opened, whereby the compressive fluid stored in the tank 407 is supplied to the reaction vessel 413 without going through the addition pot 411. As a result, the ring-opening polymerizable monomer and initiator stored in advance in the reaction vessel 413 come into contact with the compressive fluid supplied from the tank 407, and are stirred by the stirring device to be ring-opening polymerizable monomer. And other raw materials melt. In the polymerization step, the ring-opening polymerizable monomer is preferably melted by bringing a raw material containing the ring-opening polymerizable monomer into contact with a compressive fluid. When ring-opening polymerization is performed by melting the ring-opening polymerizable monomer, the reaction can proceed with a high ratio of raw materials, so that the efficiency of the reaction is improved.

In this case, the mass ratio between the raw material and the compressive fluid in the reaction vessel 413 (hereinafter also referred to as a mixing ratio) is not particularly limited, but is more preferably in the range of the following inequality.

 

In this embodiment, the raw material in the above formula includes a ring-opening polymerizable monomer and an initiator. There is no restriction | limiting in particular as said mixing ratio, Although it can select suitably according to the objective, 0.5 or more are preferable, 0.7 or more are more preferable, 0.85 or more are especially preferable. Further, the upper limit of the mixing ratio is preferably less than 1, and if the mixing ratio is less than 0.5, it is not economical because the amount of compressive fluid used increases, Since the density decreases, the polymerization rate may decrease. Further, if the mixing ratio is less than 0.5, the mass of the compressive fluid becomes larger than the mass of the raw material, so that the melt phase in which the ring-opening polymerizable monomer is melted and the ring-opening polymerizable monomer is in the compressive fluid The fluid phase dissolved in the coexistence may coexist and the reaction may not easily proceed.

The temperature and pressure at which the ring-opening polymerizable monomer is melted in the reaction vessel 413 is set to a temperature and pressure at least equal to or higher than the triple point of the compressive fluid in order to prevent the supplied compressive fluid from turning into a gas. Be controlled. This control is performed by adjusting the output of the heater of the reaction vessel 413 or the opening / closing degree of the valves (421, 422). In the present embodiment, the temperature at which the ring-opening polymerizable monomer is melted may be a temperature equal to or lower than the melting point at normal pressure of the ring-opening polymerizable monomer. This is because the pressure in the reaction vessel 413 becomes high in the presence of the compressive fluid, and the melting point of the ring-opening polymerizable monomer is lowered. For this reason, the ring-opening polymerizable monomer melts in the reaction vessel 413 even when the amount of the compressive fluid is small and the mixing ratio is large.

Also, the timing at which heat or agitation is applied to each raw material and compressive fluid in the reaction vessel 413 may be adjusted so that each raw material is efficiently melted. In this case, after bringing each raw material and the compressive fluid into contact, heat or stirring may be applied, or heat or stirring may be applied while bringing each raw material into contact with the compressive fluid. In addition, the ring-opening polymerizable monomer may be brought into contact with the compressive fluid after previously melting the ring-opening polymerizable monomer by applying heat equal to or higher than the melting point.

Subsequently, the valves (423 and 424) are opened, and the catalyst in the addition pot 411 is supplied into the reaction vessel 413. The catalyst supplied to the reaction vessel 413 is sufficiently stirred by a stirring device of the reaction vessel 413 as necessary, and heated to a predetermined temperature by a heater. As a result, in the reaction vessel 413, the ring-opening polymerizable monomer is subjected to ring-opening polymerization in the presence of a catalyst to produce a polymer.
Also, in this embodiment, two types of organic catalyst and metal catalyst are used. Even if the polymer intermediate is first produced using the organic catalyst and then the polymer product is produced using the metal catalyst, the metal catalyst is first produced. The catalyst may be used to produce a polymer intermediate followed by an organic catalyst to produce a polymer product, or simultaneously an organic catalyst and a metal catalyst to produce a polymer product. The order of addition of the catalyst is appropriately selected according to the purpose, but the raw material containing the ring-opening polymerizable monomer and the compressive fluid are brought into contact with each other in the presence of the organic catalyst not containing the metal atom. A method of further polymerizing the ring-opening polymerizable monomer in the presence of the metal catalyst after ring-opening polymerization of the ring-opening polymerizable monomer is more preferable in terms of improving the conversion.

The lower limit of the temperature (polymerization reaction temperature) for ring-opening polymerization of the ring-opening polymerizable monomer is preferably 50 ° C. lower than the melting point of the ring-opening polymerizable monomer, and 40 ° C. lower than the melting point. Is more preferable. The upper limit is preferably a temperature that is 50 ° C. higher than the melting point of the ring-opening polymerizable monomer, and more preferably a temperature that is 40 ° C. higher than the melting point. If the polymerization reaction temperature is less than 50 ° C. lower than the melting point of the ring-opening polymerizable monomer, the reaction rate tends to decrease, and the polymerization reaction may not proceed quantitatively. Further, when the polymerization reaction temperature exceeds 50 ° C. higher than the melting point of the ring-opening polymerizable monomer, the depolymerization reaction also occurs in equilibrium, so that the polymerization reaction is difficult to proceed quantitatively. However, depending on the combination of the compressive fluid, the ring-opening polymerizable monomer, and the catalyst, the ring-opening polymerizable monomer may be subjected to ring-opening polymerization at a temperature other than the above range. For example, in the case of using a ring-opening polymerizable monomer having a low melting point such as a ring-opening polymerizable monomer that is liquid at room temperature, the temperature may be higher than the above range in order to increase the activity of the catalyst. The polymerization reaction temperature is preferably 150 ° C. or lower, and more preferably 100 ° C. or lower.

In a conventional method for producing a polymer using supercritical carbon dioxide, since supercritical carbon dioxide has low polymer solubility, ring-opening polymerizable monomers were polymerized using a large amount of supercritical carbon dioxide. According to the polymerization method of the present embodiment, in the method for producing a polymer using a compressive fluid, the ring-opening polymerizable monomer is subjected to ring-opening polymerization at a high mixing ratio that has not been conventionally obtained. In this case, the inside of the reaction vessel 413 becomes a high pressure in the presence of the compressive fluid, and the glass transition temperature (Tg) of the produced polymer is lowered. As a result, the viscosity of the produced polymer is lowered, so that the ring-opening polymerization reaction proceeds even when the polymer concentration is high.

In this embodiment, the polymerization reaction time is set according to the target molecular weight. When the target weight average molecular weight is 3,000 to 500,000, the polymerization reaction time is completed within 2 hours.

The pressure at the time of polymerization, that is, the pressure of the compressive fluid is such that the compressive fluid supplied from the tank 407 is a liquefied gas ((2) in the phase diagram of FIG. 2) or a high-pressure gas ((3 in the phase diagram of FIG. 2). )) May be used, but a pressure which becomes a supercritical fluid ((1) in the phase diagram of FIG. 2) is preferable. By making the compressible fluid into a supercritical fluid state, melting of the ring-opening polymerizable monomer is promoted, and the polymerization reaction can be promoted uniformly and quantitatively. When carbon dioxide is used as the compressive fluid, the pressure is preferably 3.7 MPa or more, more preferably 5 MPa or more, and a critical pressure of 7.4 PMa or more in consideration of efficiency of the reaction, polymer conversion rate, and the like. Particularly preferred. Moreover, when using a carbon dioxide as a compressive fluid, it is preferable that the temperature is 25 degreeC or more for the same reason.

The amount of water in the reaction vessel 413 is preferably 4 mol% or less, more preferably 1 mol% or less, and particularly preferably 0.5 mol% or less with respect to the ring-opening polymerizable monomer. When the amount of water exceeds 4 mol%, the water itself contributes as an initiator, so that it may be difficult to control the molecular weight. In order to control the amount of water in the polymerization reaction system, an operation for removing water contained in the ring-opening polymerizable monomer and other raw materials may be added as a pretreatment as necessary.

It is also possible to introduce a urethane bond or an ether bond to the polymer obtained by polymerizing the ring-opening polymerizable monomer. This urethane bond or ether bond can be introduced by adding an isocyanate compound or a glycidyl compound and carrying out a polyaddition reaction in a compressive fluid, like the ring-opening polymerizable monomer. In this case, in order to control the molecular structure, a method in which the compound is added and reacted after completion of the polymerization reaction of the ring-opening polymerizable monomer is more preferable.

The isocyanate compound used in the polyaddition reaction is not particularly limited, and examples thereof include polyfunctional isocyanate compounds such as isophorone diisocyanate, hexamethylene diisocyanate, lysine diisocyanate, xylene diisocyanate, tolylene diisocyanate, diphenylmethane diisocyanate, and cyclohexane diisocyanate. The glycidyl compound is not particularly limited, and examples thereof include polyfunctional glycidyl compounds such as diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and diglycidyl terephthalate. .

The polymer P that has completed the ring-opening polymerization reaction in the reaction vessel 413 is discharged from the valve 425 and sent out of the reaction vessel 413.

-Other improvements-
As a further improvement of the method for producing the polymer of the present invention, the following treatment may be added.
When the ring-opening polymerizable monomer is subjected to ring-opening polymerization, at least one of an organic catalyst not containing the metal atom and a catalyst containing the metal atom may be held in the reaction vessel in advance.
That is, a reaction in which at least one of the organic catalyst containing no metal atom and the catalyst containing the metal atom is retained by bringing the raw material containing the ring-opening polymerizable monomer into contact with the compressive fluid. The ring-opening polymerizable monomer may be subjected to ring-opening polymerization in a container. More specifically, after bringing the raw material containing the ring-opening polymerizable monomer into contact with the compressive fluid, each raw material after melting in a reaction vessel in which a solid metal catalyst is applied in advance. An organic catalyst may be supplied to cause the ring-opening polymerizable monomer to undergo ring-opening polymerization.

In the polymer production method of the present invention, the ring-opening polymerization step may further include a treatment for removing at least one of the organic catalyst containing no metal atom and the catalyst containing the metal atom. Good.
The catalyst remaining in the polymer product obtained by the polymer production method is removed if necessary. The removal method is not particularly limited.For example, if it is a compound having a boiling point, it is distilled off under reduced pressure, or a method of removing the catalyst by using a substance that dissolves the catalyst as an entrainer, For example, a method of adsorbing and removing a catalyst by a column may be used. In this case, the method for removing the catalyst may be a batch method in which the polymer product is removed after being taken out from the reaction vessel, or a method in which the polymer product is continuously treated without being taken out. In the case of distilling off under reduced pressure, the reduced pressure condition is set based on the boiling point of the catalyst. For example, the temperature during decompression is 100 ° C. or higher and 120 ° C. or lower, and the catalyst can be removed at a temperature lower than the temperature at which the polymer product is depolymerized. When an organic solvent is used in this extraction operation, a step for removing the organic solvent after extraction of the catalyst may be required. For this reason, it is preferable to use a compressed fluid as a solvent also in extraction operation. As such an extraction operation, a known technique such as extraction of a fragrance can be diverted.
More specifically, the raw material containing the ring-opening polymerizable monomer is brought into contact with the compressive fluid to open the ring-opening polymerizable monomer in the presence of the organic catalyst not containing the metal atom. After the polymerization, the organic catalyst not containing the metal atom remaining in the produced polymer intermediate is removed, and then further polymerized in the presence of the catalyst containing the metal atom to obtain a polymer product. From the viewpoint of improving the conversion rate.

<< Polymer product >>
According to the method for producing a polymer of the present invention, the use of a compressive fluid enables a polymerization reaction at a low temperature as described above, so that the depolymerization reaction is greatly suppressed as compared with conventional melt polymerization. it can. Thereby, even in the case of a continuous process or a batch process, the polymer conversion rate can be 97 mol% or more, preferably 98 mol% or more. When the polymer conversion rate is less than 97 mol%, the thermal characteristics as the polymer product may be insufficient, and an operation for separately removing the ring-opening polymerizable monomer may be required. In the present embodiment, the polymer conversion rate means the ratio of the ring-opening polymerizable monomer that has contributed to the formation of the polymer with respect to the ring-opening polymerizable monomer as a raw material. The amount of the ring-opening polymerizable monomer that contributed to the production of the polymer can be obtained by subtracting the amount of the unreacted ring-opening polymerizable monomer (residual ring-opening polymerizable monomer) from the amount of the produced polymer.

The number average molecular weight of the polymer obtained by this embodiment can be adjusted by the amount of the initiator. Although not particularly limited, the number average molecular weight is generally from 12,000 to 200,000. When the number average molecular weight is larger than 200,000, it may not be economical due to a deterioration in productivity accompanying an increase in viscosity. When the number average molecular weight is less than 12,000, the strength as a polymer may be insufficient, which may not be preferable. The value obtained by dividing the weight average molecular weight of the polymer obtained by this embodiment by the number average molecular weight is preferably in the range of 1.0 to 2.5, and more preferably in the range of 1.0 to 2.0. When this value is larger than 2.0, there is a high possibility that the polymerization reaction is performed non-uniformly, and it is difficult to control the physical properties of the polymer.

Since the polymer product obtained by this embodiment is produced by a production method that does not use an organic solvent, the organic product is substantially free of an organic solvent, and the content of metal atoms can be reduced by using a very small amount of a metal catalyst. Since the amount of residual monomer is as low as 1000 ppm or less, it is excellent in safety and stability. Moreover, as a result of carrying out the polymerization reaction by reducing the amount of the catalyst used at a low temperature for a short time, a polymer product having no coloration is obtained, which is excellent in practicality. Therefore, the polymer product of the present embodiment is widely applied for uses such as daily necessities, pharmaceuticals, cosmetics, and electrophotographic toners. In the present embodiment, the organic solvent is an organic solvent used for ring-opening polymerization. The phrase “substantially free of organic solvent” means that the content of the organic solvent in the polymer product measured by the following measurement method is below the detection limit.

--Measurement method of residual organic solvent--
Add 2 parts by mass of 2-propanol to 1 part by mass of the polymer product to be measured, disperse with ultrasound for 30 minutes, and store in a refrigerator (5 ° C.) for 1 day or longer. Organic solvent in the polymer product To extract. The supernatant is analyzed by gas chromatography (GC-14A, SHIMADZU), and the organic solvent concentration is measured by quantifying the organic solvent and residual monomers in the polymer product. Measurement conditions at the time of such analysis are as follows.
Equipment: Shimadzu GC-14A
Column: CBP20-M 50-0.25
Detector: FID
Injection volume: 1 μL to 5 μL
Carrier gas: He 2.5 kg / cm ²
Hydrogen flow rate: 0.6 kg / cm ²
Air flow rate: 0.5 kg / cm ²
Chart speed: 5mm / min
Sensitivity: Range101 × Atten20
Column temperature: 40 ° C
Injection Temp: 150 ° C

-Uses of polymer products-
The polymer product obtained by the method for producing a polymer of the present invention is excellent in safety and stability because it has a small metal content and a small amount of residual monomer. Therefore, the polymer product obtained by the production method of the present embodiment is widely applied to various uses such as an electrophotographic developer, printing ink, architectural paint, cosmetics, and medical materials. At that time, various additives may be used for the purpose of improving moldability, secondary processability, decomposability, tensile strength, heat resistance, storage stability, crystallinity, weather resistance and the like.

-Effects of the polymer production method of the present invention-
According to the method for producing a polymer of the present invention, for the following reasons, it is possible to provide a polymer product that is excellent in terms of low cost, low environmental load, energy saving, and resource saving, and excellent in molding processability and thermal stability. .
(1) The reaction proceeds at a low temperature as compared with the melt polymerization method in which the reaction is performed at a high temperature (for example, 150 ° C. or higher).
(2) Since the reaction proceeds at a low temperature, almost no side reaction occurs, and a polymer product is obtained in a high yield with respect to the added ring-opening polymerizable monomer (that is, there are few unreacted ring-opening polymerizable monomers). . Thereby, a purification process such as removal of an unreacted ring-opening polymerizable monomer for obtaining a polymer excellent in molding processability and thermal stability can be simplified or omitted.
(3) In the polymerization method using an organic solvent, a step of removing the solvent is required in order to use the obtained polymer product as a solid. In the polymerization method of this embodiment, since a compressive fluid is used, no waste liquid or the like is generated, and a dried polymer product is obtained in a single step, so that the drying step can be simplified or omitted.
(4) Since a compressive fluid is used, the ring-opening polymerization reaction can be performed without using an organic solvent. The organic solvent means a liquid organic compound used for dissolving the ring-opening polymerizable monomer.
(5) When the ring-opening polymerizable monomer is melted in the compressive fluid and then the catalyst is added to cause ring-opening polymerization, the reaction proceeds uniformly. For this reason, it is suitably used when obtaining a copolymer with an optical isomer or other monomer species.

(Application example of the polymer production method of the present invention)
As an application example of one embodiment (also referred to as the first embodiment) described above as the method for producing the polymer of the present invention, another embodiment (also referred to as the second embodiment) will be described. In the production method of the first embodiment, the reaction proceeds quantitatively with almost no residual monomer. Therefore, in the second embodiment, a composite is synthesized by appropriately setting the timing of adding several types of ring-opening polymerizable monomers using the polymer product produced by the production method of the first embodiment. To do. In the present embodiment, the composite is obtained by polymerizing a copolymer or monomer having two or more polymer segments obtained by polymerizing monomers in a plurality of series. It means a mixture of two or more polymers. Hereinafter, as an example of the complex, two methods for synthesizing a stereo complex will be described.

<First method>
First, the first method will be described with reference to FIGS. 6A and 6B. 6A and 6B are schematic views showing a complex production system used in the first method. In the first method, a polymer is produced by the production method of the first embodiment in series 1 in the complex production system 200 of FIG. 6A, and the obtained polymer product P and the newly introduced second product are used. A composite product PP (final polymer product) is produced by contacting the ring-opening polymerizable monomer in series 2 and mixing continuously in the presence of a compressive fluid. In addition, the complex product PP which has a 3 or more types of segment can also be obtained by repeating the series similar to the series 2 in the complex manufacturing system 200 of FIG. 6A in series.

Next, a specific example of the complex manufacturing system 200 will be described with reference to FIG. 6B. The complex production system 200 includes a polymerization reaction device 100, tanks (21, 27), a metering feeder 22, a metering pump 28, a melt mixing device 29, and a reaction similar to those used in the first embodiment. A container 33 and a pressure adjusting valve 34 are provided.
In the complex production system 200, the polymer introduction port 33 a of the reaction vessel 33 is connected to the discharge port of the polymerization reaction apparatus 100 via the pressure resistant pipe 31. Here, the outlet of the polymerization reaction apparatus 100 means the outlet of the reaction vessel 13, the metering pump 14 (FIG. 3), or the pressure regulating valve 16 (FIG. 4). In any case, the polymer product P generated in each polymerization reaction apparatus 100 can be supplied to the reaction vessel 33 in a molten state without returning to normal pressure.

Tank 21 stores the second ring-opening polymerizable monomer. In the first method, the second ring-opening polymerizable monomer is an optical isomer of the ring-opening polymerizable monomer stored in the tank 1. The tank 27 stores a compressible fluid. The compressive fluid stored in the tank 27 is not particularly limited, but is preferably the same type as the compressive fluid stored in the tank 7 in order to advance the polymerization reaction uniformly. The tank 27 may store a gas (gas) or a solid that is a compressible fluid in the course of being supplied to the melt mixing device 29, or heated or pressurized in the melt mixing device 29. . In this case, the gas or solid stored in the tank 27 is heated or pressurized to be in the state of (1), (2), or (3) in the phase diagram of FIG. Become.

The metering feeder 22 measures the second ring-opening polymerizable monomer stored in the tank 21 and continuously supplies it to the melt mixing device 29. The metering pump 28 continuously supplies the compressive fluid stored in the tank 27 to the melt mixing device 29 at a constant pressure and flow rate. The melt mixing device 29 is a pressure-resistant container for continuously bringing the second ring-opening polymerizable monomer supplied from the tank 21 and the compressive fluid supplied from the tank 27 into contact with each other to melt the raw materials. It is a device that has. Into the container of the melt mixing device 29, the introduction port 29 a for introducing the compressive fluid supplied from the tank 27 by the metering pump 28 and the second ring-opening polymerizable monomer supplied from the tank 21 by the metering feeder 22 are introduced. And an introduction port 29b. In the present embodiment, as the melt mixing device 29, the same one as the melt mixing device 9 is used.

The reaction vessel 33 is obtained by polymerization in the polymerization reactor 100, and the polymer product P as an intermediate melted in the compressive fluid, and a second opening that is melted in the compressive fluid by the melt mixing device 29. It is a pressure-resistant container for polymerizing a ring polymerizable monomer. Into the reaction vessel 33, the inlet 33a for introducing the molten polymer product P as an intermediate into the vessel and the molten second ring-opening polymerizable monomer are introduced into the vessel. An introduction port 33b is provided. In the present embodiment, the same reaction vessel 33 as the reaction vessel 13 is used. The pressure adjusting valve 34 sends out the complex product PP polymerized in the reaction vessel 33 to the outside of the reaction vessel 33 by utilizing the pressure difference between the inside and outside of the reaction vessel 33.
In the first method, a ring-opening polymerizable monomer (for example, L-lactide) is polymerized in the reaction vessel 13 and the reaction is quantitatively terminated, and then an optical isomer as an example of the second ring-opening polymerizable monomer. The ring-opening polymerizable monomer (for example, D-lactide) is added to the reaction vessel 33, and the polymerization reaction is further performed. Thereby, a stereo block copolymer is obtained. This method is very useful because the reaction can proceed at a temperature below the melting point of the ring-opening polymerizable monomer with a small amount of residual monomer, so that racemization hardly occurs and the reaction is obtained in a one-step reaction.

<Second method>
Subsequently, the second method will be described with reference to FIG. FIG. 7 is a schematic diagram showing a complex production system used in the second method. In the second method, a composite product PP is produced by continuously mixing a plurality of polymer products produced by the production method of the first embodiment in the presence of a compressive fluid. The plurality of polymer products are obtained by polymerizing ring-opening polymerizable monomers of optical isomers to each other. The complex manufacturing system 300 includes a plurality of polymerization reaction devices 100, a mixing device 41, and a pressure adjustment valve 42.

In the complex production system 300, the polymer inlet 41 a of the mixing device 41 is connected to the outlet of each polymerization reaction device 100 via the pressure resistant pipe 31. Here, the outlet of the polymerization reaction apparatus 100 means the outlet of the reaction vessel 13, the metering pump 14 (FIG. 3), or the pressure regulating valve 16 (FIG. 4). In any case, the polymer product P generated in each polymerization reaction device 100 can be supplied to the mixing device 41 in a molten state without returning to normal pressure. As a result, each polymer product P has a reduced viscosity in the presence of the compressed fluid, so that the mixing device 41 can mix two or more types of polymer products P at a lower temperature. FIG. 7 shows an example in which the piping 31 has one joint 31a so that two polymerization reaction apparatuses 100 are provided in parallel. However, by providing a plurality of joints, the polymerization reaction apparatus 100 can be connected in three in parallel. You may have more than one.

The mixing device 41 is not limited as long as it can mix a plurality of polymer products supplied from the respective polymerization reaction devices 100, and includes a stirring device. As the agitation device, a uniaxial screw, a biaxial screw meshing with each other, a biaxial mixer having a large number of meshing elements meshing with each other or overlapping, a kneader having helical stirring elements meshing with each other, a static mixer, etc. are preferably used. . The temperature (mixing temperature) at which each polymer product is mixed by the mixing device 41 can be set similarly to the polymerization reaction temperature in the reaction vessel 13. The mixing device 41 may have a mechanism for supplying a compressive fluid separately to the polymer product to be mixed. The pressure adjusting valve 42 is a device for adjusting the flow rate of the composite product PP obtained by mixing the polymer product with the mixing device 41.

In the second method, L-type and D-type monomers (for example, lactide) are polymerized in advance in the compressive fluid in the polymerization reaction apparatus 100 in advance. Furthermore, the polymer product obtained by polymerization is blended in a compressive fluid to obtain a stereoblock copolymer. In general, polymers such as polylactic acid often decompose when heated and dissolved again, even when the residual monomer is extremely small. The second method is useful because, by blending low-viscosity polylactic acid melted with a compressive fluid at a melting point or lower, racemization and thermal degradation can be suppressed as in the first method.

In the first method and the second method, a case where a stereocomplex is produced by polymerizing ring-opening polymerizable monomers that are optical isomers to each other has been described. However, the ring-opening polymerizable monomers used in this embodiment do not need to be optical isomers. Moreover, it is also possible to mix the block copolymer which forms a stereocomplex by combining the 1st method and the 2nd method.

Hereinafter, the present embodiment will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. “Ppm” in each table indicates a mass fraction. The molecular weight, polymer conversion rate, YI value, and residual catalyst amount of the polymer products obtained in Examples and Comparative Examples were determined as follows.

<Measurement of molecular weight of polymer product>
The measurement was carried out under the following conditions by GPC (Gel Permeation Chromatography).
・ Device: GPC-8020 (manufactured by Tosoh Corporation)
Column: TSK G2000HXL and G4000HXL (manufactured by Tosoh Corporation)
・ Temperature: 40 ℃
-Solvent: 90 wt% / 10 wt% mixture of THF (tetrahydrofuran) and dichloromethane-Flow rate: 1.0 mL / min 1 mL of a polymer product having a concentration of 0.5 mass% was injected, and the polymer product measured under the above conditions The number average molecular weight Mn and the weight average molecular weight Mw of the polymer were calculated from the molecular weight distribution using a molecular weight calibration curve prepared with a monodisperse polystyrene standard sample. The molecular weight distribution is a value obtained by dividing Mw by Mn.

<Polymer conversion of monomer>
-Polymer conversion rate of lactide Using a nuclear magnetic resonance apparatus JNM-AL300 manufactured by JEOL Ltd., nuclear magnetic resonance measurement of the product polylactic acid was performed in deuterated chloroform. In this case, the ratio of the lactide-derived quadruple peak area (4.98 to 5.05 ppm) to the polylactic acid-derived quadruple peak area (5.10 to 5.20 ppm) was calculated and multiplied by 100. This was defined as an unreacted monomer amount (mol%) (residual ring-opening polymerizable monomer amount). The polymer conversion rate is a value obtained by subtracting the amount of unreacted monomer calculated from 100.
・ Conversion rate of polymers other than lactide Polymers other than lactide were measured in the same manner as described above, and the ratio of the quadruple peak area on the low magnetic field side from the monomer to the quadruple peak area on the high magnetic field side from the polymer was calculated. Then, 100 times this was taken as the amount of unreacted monomer (mol%). The polymer conversion rate is a value obtained by subtracting the amount of unreacted monomer calculated from 100.

<Measurement of YI value>
In order to investigate the yellowness and yellowing degree of the polymer product, the polymer product was adjusted to a thickness of 1 mm in a heat press machine heated to 180 ° C., and pressed for 1 minute to obtain a polymer sheet. It was. The YI value of the obtained sheet was determined according to JIS standard K7373.

<Remaining catalyst amount>
The amount of organic catalyst remaining in the polymer product (polylactic acid) is determined by uniformly dissolving the polymer product such as polylactic acid in dichloromethane and adding an acetone / cyclohexane mixed solution (mass ratio 1/1). The supernatant obtained by re-precipitation was subjected to a gas chromatograph (GC) with a hydrogen flame detector (FID), the remaining catalyst was separated, and the amount of the remaining catalyst in the polymer product was measured by quantifying by an internal standard method. . Gas chromatography (GC) measurement was performed under the following conditions.

-GC measurement conditions-
Column: capillary column Agilent J & W GC column-DB-17 ms (manufactured by Agilent Technologies, length 30 m × inner diameter 0.25 mm, film thickness 0.25 μm)
Internal standard: 2,6-dimethyl-γ pyrone Column flow rate: 1.8 mL / min Column temperature: 50 ° C., hold for 1 minute. The temperature is raised at a constant rate of 25 ° C./min and held at 320 ° C. for 5 minutes.
・ Detector: Flame ionization method (FID)

The metal catalyst was measured under the following conditions by ICP emission spectroscopy (high frequency inductively coupled plasma emission spectroscopy), and the amount of residual catalyst was determined based on the measurement results.
・ Device: ICP emission spectroscopic analyzer (ICP-OES / ICP-AES)
A sample (polymer product) made by SPS5100, SII Nanotechnology was decomposed by heating with sulfuric acid and nitric acid (heating temperature is 230 ° C.), and then the volume was measured with ultrapure water to prepare a test solution. Quantitative analysis of Sn in the test solution was performed by ICP-AES method.

Example 1
Ring-opening polymerization of L-lactide (purity 99.5 wt%) was performed using the polymerization reactor 100 of FIG. The structure of the polymerization reaction apparatus 100 is shown.
Tank 1, weighing feeder 2:
Plunger pump NP-S462 made by Nippon Seimitsu
Tank 1 was filled with molten lactide as a ring-opening polymerizable monomer.
Tank 3, weighing feeder 4:
Intelligent spectrometer pump (PU-2080) manufactured by JASCO
Tank 3 was filled with lauryl alcohol as an initiator.
Tank 5, metering pump 6: Not used in this example.
Tank 7: Carbon dioxide cylinder tank 11, metering pump 12:
Intelligent spectrometer pump (PU-2080) manufactured by JASCO
The tank 11 was filled with DBU (organic catalyst).
Melt mixing device 9: biaxial stirring device with screws that mesh with each other Cylinder inner diameter 30 mm
Cylinder set temperature 100 ℃
Two shafts rotating in the same direction Rotating speed 30rpm
Reaction vessel 13: Biaxial kneader Cylinder inner diameter 40mm
Cylinder set temperature Raw material supply part 100 ℃ Tip part 80 ℃
Two shafts rotating in the same direction Rotation speed 60rpm

The melt mixing device 9 and the reaction vessel 13 were operated under the above set conditions. The weighing feeder 2 quantitatively supplied the molten lactide in the tank 1 into the container of the melt mixing device 9. The measuring feeder 4 has 0.07 mol of lauryl alcohol in the tank 3 such that the amount of initiator relative to the ring-opening polymerizable monomer is 0.07 mol%, that is, 1 mol of lactide is supplied. Thus, a fixed amount was supplied into the container of the melt mixing apparatus 9. The metering pump 8 is placed in the pipe of the melt mixing device 9 so that the carbon dioxide (carbon dioxide) as a compressive fluid from the tank 7 becomes 10 parts by mass with respect to 90 parts by mass of the raw material supplied per unit time. Continuously fed. That is, the feed ratio was set to the feed rate of raw materials (g / min) / [feed rate of raw materials (g / min) + feed rate of compressible fluid (g / min)] = 90/100 = 0.9. Here, the raw materials are lactide which is a ring-opening polymerizable monomer and lauryl alcohol added as an initiator. The feed amount of the raw material was 10 g / min. It supplied so that the pressure in the container of the melt mixing apparatus 9 might be set to 15 MPa. As a result, the melt mixing device 9 continuously brings the raw materials of lactide and lauryl alcohol supplied from the tanks (1, 3, 7) and the compressive fluid into contact with each other and mixes them with a screw. Was melted.

Each material melted by the melt mixing device 9 was sent to the reaction vessel 13 by the liquid feed pump 10. The metering pump 12 supplied the organic catalyst (DBU) in the tank 11 to the raw material supply hole of the biaxial kneader as the reaction vessel 13 so as to be 200 ppm with respect to 1 part by mass of lactide.
In the reaction vessel 13, each material fed by the liquid feed pump 10 and DBU supplied by the metering pump 12 were mixed, and lactide was subjected to ring-opening polymerization.
Immediately after mixing with the organic catalyst, the tank 11 is filled with a metal catalyst (bis (2-ethylhexanoic acid) tin (II)), and the metering pump 12 is charged with metal catalyst (bis ( 2-Ethylhexanoic acid) tin (II)) was supplied to the raw material supply hole of the twin-screw kneader as the reaction vessel 13 so as to be 200 ppm.

In the reaction vessel 13, lactide was subjected to ring-opening polymerization in the presence of an organic catalyst, and then further polymerized in the presence of a metal catalyst.
At this time, the temperature of the melt mixing device 9 was increased to 150 ° C., and the temperature of the reaction vessel 13 was increased to 150 ° C. In this case, the average residence time of each material in the reaction vessel 13 was about 1,200 seconds.
A metering pump 14 and an extrusion cap 15 were attached to the tip of the reaction vessel 13. The feed rate of the polymer (polylactic acid) as the product of the metering pump 14 was 200 g / min. With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. The results are shown in Table 1.

(Example 2)
Ring-opening polymerization of L-lactide (purity 99.5 wt%) was performed using the polymerization reactor 100 of FIG. The structure of the polymerization reaction apparatus 100 is shown.
Tank 1, weighing feeder 2:
Plunger pump NP-S462 made by Nippon Seimitsu
Tank 1 was filled with molten lactide as a ring-opening polymerizable monomer.
Tank 3, weighing feeder 4:
Intelligent spectrometer pump (PU-2080) manufactured by JASCO
Tank 3 was filled with lauryl alcohol as an initiator.
Tank 5, metering pump 6: Not used in this example.
Tank 7: Carbon dioxide cylinder tank 11, metering pump 12:
Intelligent spectrometer pump (PU-2080) manufactured by JASCO
Tank 11 was filled with metal catalyst bis (2-ethylhexanoate) tin.
Melt mixing device 9: biaxial stirring device with screws that mesh with each other Cylinder inner diameter 30 mm
Cylinder set temperature 150 ℃
Two shafts rotating in the same direction Rotating speed 30rpm
Reaction vessel 13: Biaxial kneader Cylinder inner diameter 40mm
Cylinder set temperature Raw material supply part 150 ° C Tip part 80 ° C
Two shafts rotating in the same direction Rotation speed 60rpm

The melt mixing device 9 and the reaction vessel 13 were operated under the above set conditions. The weighing feeder 2 quantitatively supplied the molten lactide in the tank 1 into the container of the melt mixing device 9. The measuring feeder 4 quantitatively supplied the lauryl alcohol in the tank 3 into the container of the melt mixing device 9 so as to be 0.07 mol per mol of lactide supplied. The metering pump 8 is placed in the pipe of the melt mixing device 9 so that the carbon dioxide (carbon dioxide) as a compressive fluid from the tank 7 becomes 10 parts by mass with respect to 90 parts by mass of the raw material supplied per unit time. Continuously fed. That is, the feed ratio was set to the feed rate of raw materials (g / min) / [feed rate of raw materials (g / min) + feed rate of compressible fluid (g / min)] = 90/100 = 0.9. Here, the raw materials are lactide which is a ring-opening polymerizable monomer and lauryl alcohol added as an initiator. The feed amount of the raw material was 10 g / min. It supplied so that the pressure in the container of the melt mixing apparatus 9 might be set to 15 MPa. As a result, the melt mixing device 9 continuously brings the raw materials of lactide and lauryl alcohol supplied from the tanks (1, 3, 7) and the compressive fluid into contact with each other and mixes them with a screw. Was melted.

Each material melted by the melt mixing device 9 was sent to the reaction vessel 13 by the liquid feed pump 10. The metering pump 12 supplied the metal catalyst (bis (2-ethylhexanoic acid) tin) in the tank 11 to the raw material supply hole of the twin-screw kneader as the reaction vessel 13 so as to be 200 ppm with respect to 1 part by mass of lactide. .
In the reaction vessel 13, each material fed by the liquid feeding pump 10 and bis (2-ethylhexanoic acid) tin supplied by the metering pump 12 were mixed to perform ring-opening polymerization of lactide.
Immediately after mixing with the metal catalyst, the tank 11 is filled with DBU (organic catalyst), and the feed pump of the biaxial kneader as the reaction vessel 13 so that the metering pump 12 becomes 200 ppm of DBU with respect to 1 part by mass of lactide. Supplied.

In the reaction vessel 13, lactide was subjected to ring-opening polymerization in the presence of a metal catalyst, and then further polymerized in the presence of an organic catalyst.
At this time, the temperature of the melt mixing device 9 was lowered to 100 ° C., and the temperature of the reaction vessel 13 was lowered to 100 ° C. In this case, the average residence time of each material in the reaction vessel 13 was about 1,200 seconds.
A metering pump 14 and an extrusion cap 15 were attached to the tip of the reaction vessel 13. The feed rate of the polymer (polylactic acid) as the product of the metering pump 14 was 200 g / min. With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. The results are shown in Table 1.

(Example 3) to (Example 5)
Experiments were conducted in the same manner as in (Example 1) except that the catalyst type used in Example 1 was changed to the material shown in Table 1 instead of DBU. With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. The results are shown in Table 1.

(Example 6) to (Example 8)
In Example 2, the experiment was performed in the same manner as in (Example 2) except that the catalyst type used was changed to the material shown in Table 1 instead of DBU. With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. The results are shown in Table 1.

Example 9
Experiments were conducted in the same manner as in (Example 1) except that the amount of lauryl alcohol added in Example 1 was changed as shown in Table 1. With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. The results are shown in Table 1.

(Example 10) to (Example 23)
Experiments were conducted in the same manner as in (Example 1) except that the types of monomers used in Example 1 were changed as shown in Tables 1 to 3. For the combinations of the two types of monomers (Example 16) to (Example 23), each of the monomers was synthesized one by one and charged into the reaction vessel 100 of FIG. went. With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. Table 2 shows the results of Examples 10 to 18, and Table 3 shows the results of Examples 19 to 23.

(Example 24)
The experiment was performed in the same manner as in (Example 1) except that the order of the catalyst to be added was changed so as to be mixed at the same time in Example 1. With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. The results are shown in Table 3.

(Example 25)
In Example 1, the experiment was performed in the same manner as in (Example 1) except that the amount of the initiator to be added was 0.01 mol with respect to 1 mol of lactide. With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. The results are shown in Table 3.

(Example 26)
In Example 1, tin oxide (manufacturer name: Aldrich cat, no24, 464-3. Tin (ii)) which was previously sieved on the wall of the tube of the reaction vessel 13 in FIG. Oxide, 99-%) was applied uniformly to 1 g, and the same experiment as in Example 1 was conducted except that the metal catalyst (bis (2-ethylhexanoic acid) tin (II)) was not used. Went. With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. The results are shown in Table 3.

(Example 27)
Ring-opening polymerization of L-lactide was performed using the polymerization reaction apparatus 400 of FIG. The structure of the polymerization reaction apparatus 400 is shown.
Tank 407: Carbon dioxide cylinder addition pot 411: A 1/4 inch SUS316 pipe was sandwiched between valves 423 and 424 and used as an addition pot.
DBU was previously filled to 200 ppm with respect to 1 part by mass of lactide.
Reaction vessel 413: 100 mL pressure vessel made of SUS316 Preliminarily lactide in a liquid state as a ring-opening polymerizable monomer,
Mixture with lauryl alcohol as initiator (molar ratio 100/3)
108 g was charged.

By operating the metering pump 408 and opening the valves (421, 422), the carbon dioxide stored in the tank 407 was supplied to the reaction vessel 413 without going through the addition pot 411. After replacing the space in the reaction vessel 413 with carbon dioxide, carbon dioxide was charged until the pressure in the reaction vessel 413 reached 15 MPa. After the temperature in the reaction vessel 413 was raised to 100 ° C., the valve (423, 424) was opened, and the DBU in the addition pot 411 was supplied into the reaction vessel 413. Thereafter, a polymerization reaction of lactide was performed in the reaction vessel 413 for 1 hour.
During this time, a metal catalyst (bis (2-ethylhexanoic acid) tin (II)) was charged in the addition pot 411 so that the concentration was 200 ppm with respect to 1 part by mass of lactide.

After completion of the reaction, the metering pump 408 was operated and the valves (421, 422) were opened to supply the carbon dioxide stored in the tank 407 to the reaction vessel 413 without going through the addition pot 411. After replacing the space in the reaction vessel 413 with carbon dioxide, carbon dioxide was charged until the pressure in the reaction vessel 413 reached 15 MPa. After raising the temperature in the reaction vessel 413 to 150 ° C., the valve (423, 424) is opened, and the metal catalyst (bis (2-ethylhexanoic acid) tin (II)) in the addition pot 411 is placed in the reaction vessel 413. Supplied. Thereafter, a polymerization reaction of lactide was performed in the reaction vessel 413 for 1 hour.
After completion of the reaction, the valve 425 was opened, the temperature and pressure in the reaction vessel 413 were gradually returned to room temperature and normal pressure, and after 3 hours, the polymer product (polylactic acid) in the reaction vessel 413 was taken out.

Space volume of supercritical carbon dioxide: 100mL-108g / 1.27 (specific gravity of raw materials) = 15mL
Mass of supercritical carbon dioxide: 15 mL × 0.303 (specific gravity of carbon dioxide at 110 ° C. and 15 MPa) = 4.5
Mixing ratio: 108 g / (108 g + 4.5 g) = 0.96

The physical properties (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) of the obtained polymer product were determined by the above method. The results are shown in Table 4.

(Example 28)
Ring-opening polymerization of L-lactide was performed using the polymerization reaction apparatus 400 of FIG. The structure of the polymerization reaction apparatus 400 is shown.
Tank 407: Carbon dioxide cylinder addition pot 411: A 1/4 inch SUS316 pipe was sandwiched between valves 423 and 424 and used as an addition pot.
In advance, a metal catalyst (bis (2-ethylhexanoic acid) tin (II)) was charged to 200 ppm with respect to 1 part by mass of lactide.
Reaction vessel 413: 100 ml pressure vessel made of SUS316 Preliminarily liquid lactide as a ring-opening polymerizable monomer,
Mixture with lauryl alcohol as initiator (molar ratio 100/3)
108 g was charged.

The carbon dioxide stored in the tank 407 was supplied to the reaction vessel 413 without going through the addition pot 411 by operating the metering pump 408 and opening the valves (421, 422). After replacing the space in the reaction vessel 413 with carbon dioxide, carbon dioxide was charged until the pressure in the reaction vessel 413 reached 15 MPa. After raising the temperature in the reaction vessel 413 to 150 ° C., the valve (423, 424) is opened, and the metal catalyst (bis (2-ethylhexanoic acid) tin (II)) in the addition pot 411 is placed in the reaction vessel 413. Supplied to. Thereafter, a polymerization reaction of lactide was performed in the reaction vessel 413 for 1 hour.

During this time, DBU was charged in the addition pot 411 so that the amount became 200 ppm with respect to 1 part by mass of lactide.
After completion of the reaction, the metering pump 408 was operated and the valves (421, 422) were opened to supply the carbon dioxide stored in the tank 407 to the reaction vessel 413 without going through the addition pot 411. After replacing the space in the reaction vessel 413 with carbon dioxide, carbon dioxide was charged until the pressure in the reaction vessel 413 reached 15 MPa. After the temperature in the reaction vessel 413 was lowered to 100 ° C., the valve (423, 424) was opened, and the DBU in the addition pot 411 was supplied into the reaction vessel 413. Thereafter, a polymerization reaction of lactide was performed in the reaction vessel 413 for 1 hour.
After completion of the reaction, the valve 425 was opened, the temperature and pressure in the reaction vessel 413 were gradually returned to room temperature and normal pressure, and after 3 hours, the polymer product (polylactic acid) in the reaction vessel 413 was taken out.

Space volume of supercritical carbon dioxide: 100mL-108g / 1.27 (specific gravity of raw materials) = 15mL
Mass of supercritical carbon dioxide: 15 mL × 0.303 (specific gravity of carbon dioxide at 110 ° C. and 15 MPa) = 4.5
Mixing ratio: 108 g / (108 g + 4.5 g) = 0.96

The physical properties (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) of the obtained polymer product were determined by the above method. The results are shown in Table 4.

(Example 29)
In Example 27, an experiment was performed in the same manner as in (Example 27) except that the following catalyst extraction operation was performed after the addition of the catalyst.
<Catalyst extraction process>
In the reaction apparatus 413 of FIG. 5, supercritical carbon dioxide (100 ° C., 10 MPa, 332 kg / m ³ ) and 2 mL for 30 minutes with a metering pump 408 while the obtained polymer intermediate is kept at 100 ° C. And was discharged from the valve 432, and the operation was performed so as to keep the system at 10 MPa. The polymer intermediate comes into contact with the compressive fluid, and unreacted monomer and catalyst contained in the polymer intermediate are dissolved in the compressible fluid and removed through valve 432. After the supercritical carbon dioxide circulation is completed, the temperature in the reaction vessel is increased to 150 ° C., and the reaction is performed again by adding a metal catalyst in the same manner as in (Example 27). The pressure was restored, and the polymer product (polylactic acid) in the reaction vessel was taken out from the valve 425 to obtain a polymer product.

The physical properties (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) of the obtained polymer product were determined by the above method. The results are shown in Table 4.

(Example 30)
In Example 29, the experiment was performed in the same manner as in (Example 29) except that the time for circulating supercritical carbon dioxide was 60 minutes in the extraction step.
With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. The results are shown in Table 4.

(Comparative Example 1), (Comparative Example 3), (Comparative Example 5)
The experiment was performed in the same manner as in Example 1 except that no metal catalyst was used and the temperature was set as shown in Table 5.
With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. The results are shown in Table 5.

(Comparative Example 2), (Comparative Example 4), (Comparative Example 6)
The experiment was conducted in the same manner as in Example 2 except that no organic catalyst was used and the temperature was set as shown in Table 5.
With respect to the obtained polymer product, physical property values (Mn, Mw, polymer conversion rate, YI value, catalyst residual amount) were determined by the above method. The results are shown in Table 5.

 

 

 

 

 

Aspects of the present invention are as follows, for example.
<1> comprising a ring-opening polymerization step of bringing the ring-opening polymerizable monomer into contact with a raw material containing a ring-opening polymerizable monomer and a compressive fluid;
In the ring-opening polymerization step, an organic catalyst containing no metal atom and a catalyst containing a metal atom are used.
<2> The method for producing a polymer according to <1>, wherein the raw material containing the ring-opening polymerizable monomer is brought into contact with the compressive fluid at a mixing ratio of the following formula.

<3> The method for producing a polymer according to <1>, wherein the raw material containing the ring-opening polymerizable monomer is continuously brought into contact with the compressive fluid.
<4> The method for producing a polymer according to <3>, wherein the raw material containing the ring-opening polymerizable monomer and the compressive fluid are continuously supplied and contacted under the following conditions.

<5> Any one of <1> to <4>, wherein the total amount of the organic catalyst containing no metal atom and the catalyst containing the metal atom is 50 ppm to 500 ppm based on the ring-opening polymerizable monomer This is a method for producing the polymer.
<6> From the above <1> to <5>, wherein the mass ratio (organic catalyst: metal catalyst) of the organic catalyst containing no metal atom and the catalyst containing the metal atom is 50:50 to 99: 1 It is a manufacturing method of the polymer in any one.
<7> In the ring-opening polymerization step, the ring-opening polymerizable monomer is subjected to ring-opening polymerization in the presence of an organic catalyst not containing a metal atom, and then further polymerized in the presence of a catalyst containing a metal atom. A method for producing a polymer according to any one of <1> to <6>.
<8> Any one of <1> to <7>, wherein the ring-opening polymerization step is performed in a reaction vessel in which at least one of an organic catalyst containing no metal atom and a catalyst containing a metal atom is held. A method for producing the polymer described in 1. above.
<9> The method for producing a polymer according to any one of <1> to <8>, wherein the compressive fluid contains carbon dioxide.

1, 3, 5, 7, 11, 21, 27 Tanks 2, 4, 22 Metering feeders 6, 8, 12, 14, 28 Metering pumps 9, 29 Melting and mixing device 9a Inlet (an example of compressive fluid inlet)
9b Inlet (Example of monomer inlet)
10 Liquid feed pumps 13, 33 Reaction vessel 13a Inlet 13b Inlet (an example of a catalyst inlet)
15 Extrusion cap (Example of polymer discharge port)
16 Pressure adjusting valve 30, 31 Piping 33a, 41a Polymer inlet 34 Pressure adjusting valve (an example of a composite outlet)
42 Pressure adjustment valve (an example of a composite outlet)
41 Mixing device (an example of a composite continuous manufacturing device)
100 Polymerization Reaction Device 100a Supply Device 100b Polymerization Reaction Device Body (Example of Continuous Polymer Production Device)
200, 300 Composite production system 407 Tank 408 Metering pump 411 Addition pot 413 Reaction vessel 421, 422, 423, 424, 425, 432 Valve P Polymer product PP Complex product

Claims (9)

1. A ring-opening polymerization step of bringing the ring-opening polymerizable monomer into contact with a compressive fluid and bringing the ring-opening polymerizable monomer into contact with a raw material containing the ring-opening polymerizable monomer;
   In the ring-opening polymerization step, an organic catalyst containing no metal atom and a catalyst containing a metal atom are used.
2. The method for producing a polymer according to claim 1, wherein the raw material containing the ring-opening polymerizable monomer and the compressive fluid are contacted at a mixing ratio of the following formula.
   

   
3. The method for producing a polymer according to claim 1, wherein the raw material containing the ring-opening polymerizable monomer and the compressive fluid are continuously contacted.
4. The method for producing a polymer according to claim 3, wherein the raw material containing the ring-opening polymerizable monomer and the compressive fluid are continuously supplied and contacted under the following conditions.
   

   
5. The method for producing a polymer according to any one of claims 1 to 4, wherein the total amount of the organic catalyst containing no metal atom and the catalyst containing the metal atom based on the ring-opening polymerizable monomer is 50 ppm to 500 ppm.
6. The polymer according to any one of claims 1 to 5, wherein the mass ratio of the amount of the organic catalyst not containing a metal atom to the amount of the catalyst containing the metal atom (organic catalyst: metal catalyst) is 50:50 to 99: 1. Manufacturing method.
7. The ring-opening polymerization step is to perform ring-opening polymerization of a ring-opening polymerizable monomer in the presence of an organic catalyst not containing a metal atom, and then further polymerize in the presence of a catalyst containing a metal atom. A method for producing the polymer according to any one of 1 to 6.
8. The polymer production according to any one of claims 1 to 7, wherein the ring-opening polymerization step is performed in a reaction vessel in which at least one of an organic catalyst containing no metal atom and a catalyst containing a metal atom is held. Method.
9. The method for producing a polymer according to any one of claims 1 to 8, wherein the compressive fluid contains carbon dioxide.

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