JP2016132768A - Polyamide 4 composition and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyamide 4 composition having both of mechanical strength and molding processability.SOLUTION: There are provided a polyamide 4 composition having polymethyl methacrylate conversion weight average molecular weight measured by a gel permeation chromatography of 300,000 or more, remained monomer amount of 5,000 mass.ppm or less and content of carbonate of 0.01 to 0.10 mass% and a manufacturing method of the polyamide 4 composition for ring opening polymerization of 2-pyrrolidone in the presence of carbonate.SELECTED DRAWING: None

Description

  The present invention relates to a polyamide 4 composition and a method for producing the same.

  Since polyamide 4 has the same hygroscopicity as cotton, it is attracting attention in the same manner as polyamides (polyamide 6, polyamide 66, polyamide 11, polyamide 12, etc.) that are widely used. However, polyamide 4 has points to be improved in terms of mechanical strength, moldability, and the like, and many studies have been made from the viewpoint of increasing the molecular weight in order to improve these points.

  Polyamide 4 was manufactured in 1956 by William O. Ney et al. Synthesized for the first time by ring-opening polymerization of 2-pyrrolidone by an activated monomer mechanism using metal potassium as a basic catalyst and a compound containing an acyl group as an activator (for example, patents). Reference 1). Based on this method, technical developments such as novel catalyst systems and polymerization methods have been carried out for the purpose of intermittently increasing the molecular weight and simplifying the production process from the 1950s to the 1990s (for example, patent documents). 2-5).

  Further, a method of adding a salt to improve moldability is disclosed (for example, see Patent Document 6). In the technique disclosed in this disclosure, since the amount of salt added is large, the salt has to be added immediately before processing.

  Furthermore, with the above technique, it has not been possible to obtain a polyamide 4 composition having both mechanical strength and moldability.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide a polyamide 4 composition having both mechanical strength and moldability.

Means for solving the problems are as follows. That is,
The polyamide 4 composition of the present invention has a polymethylmethacrylate conversion weight average molecular weight of 300,000 or more as measured by gel permeation chromatography, a residual monomer amount of 5,000 mass ppm or less, and a carbonate content. The amount is 0.01% by mass or more and 0.10% by mass or less.

  According to the present invention, the conventional problems can be solved, and a polyamide 4 composition having both mechanical strength and moldability can be provided.

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 a polymerization process. FIG. 4 is a system diagram showing an example of a batch polymerization process.

(Polyamide 4 composition)
The polyamide 4 composition of the present invention has a polymethyl methacrylate-converted weight average molecular weight of 300,000 or more as measured by gel permeation chromatography.
The polyamide 4 composition contains a carbonate. The carbonate content is 0.01% by mass or more and 0.10% by mass or less.
The polyamide 4 composition has a residual monomer amount of 5,000 mass ppm or less.

When the weight average molecular weight is less than 300,000, the mechanical strength becomes insufficient.
The weight average molecular weight is preferably 500,000 or more, and more preferably 1,000,000 or more.

  When the content of the carbonate in the polyamide 4 composition is less than 0.01% by mass, the moldability deteriorates, and when it exceeds 0.10% by mass, the storage stability deteriorates. Here, the deterioration of storage stability means that the mechanical strength becomes insufficient when the stored polyamide 4 composition is molded.

  The carbonate also has an effect of lowering the melting point during processing of the polyamide 4 composition, and the molded article of the polyamide 4 composition having high strength can be obtained by reducing the decrease in molecular weight due to molding. Therefore, the content of the carbonate in the polyamide 4 composition is 0.01% by mass or more and 0.10% by mass or less and 0.05% by mass with respect to the polyamide 4 composition from the viewpoint of moldability. % Or more and 0.10% by mass or less is preferable.

  The weight average molecular weight of the polyamide 4 composition can be measured, for example, as follows.

<Measurement of molecular weight of polymer>
Measurement is performed under the following conditions by GPC (Gel Permeation Chromatography).
-Equipment: GPC-8020 (manufactured by Tosoh Corporation)
Column: GMH _HR- M (manufactured by Tosoh Corporation)
・ Temperature: 40 ℃
Solvent: HFIP (hexafluoroisopropanol)
Flow rate: 0.2 mL / min 1 mL of a polymer having a concentration of 0.05% by mass was injected, and using a molecular weight calibration curve prepared by a monodisperse polymethyl methacrylate standard sample from the molecular weight distribution of the polymer measured under the above conditions, The weight average molecular weight Mw of the polymer is calculated.

  The content of the carbonate in the polyamide 4 composition can be measured by, for example, ICP-AES.

  There is no restriction | limiting in particular as said carbonate, Although it can select suitably according to the objective, Sodium carbonate and potassium carbonate are preferable from the point of reactivity and a shaping | molding process, and potassium carbonate is more preferable.

The amount of residual monomers of the polyamide 4 composition is 5,000 mass ppm, preferably 4,000 mass ppm or less. There is no restriction | limiting in particular as a lower limit of the amount of said residual monomers, According to the objective, it can select suitably, For example, 1,000 mass ppm etc. are mentioned.
When the residual monomer amount exceeds 5,000 mass ppm, the mechanical strength decreases.
The amount of the residual monomer can be determined from the peak area ratio of the polymer and the monomer in the molecular weight measurement of the polymer.

The polyamide 4 composition may be a homopolymer or a copolymer. Examples of the homopolymer include a homopolymer of 2-pyrrolidone, and examples of the copolymer include a copolymer of 2-pyrrolidone and another lactam. Examples of the other lactam include 2-azetidinone (β-propiolactam) and ε-caprolactam.
The amount of 2-pyrrolidone as a constituent monomer in the constituent components of the polyamide 4 composition is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 50% by mass or more, and 90% by mass or more. More preferred.

  There is no restriction | limiting in particular as a manufacturing method of the said polyamide 4 composition, Although it can select suitably according to the objective, The following methods are preferable.

(Production method of polyamide 4 composition)
In the method for producing the polyamide 4 composition of the present invention, 2-pyrrolidone is subjected to ring-opening polymerization in the presence of a carbonate.
The method for producing the polyamide 4 composition is a method for producing the polyamide 4 composition of the present invention.

  When the polyamide 4 composition is produced, if the carbonate is present in an amount of 0.1% by mass or more, the molecular weight is improved. Therefore, in the method for producing the polyamide 4 composition, the amount of the carbonate is 0.01% by mass or more and 0.10% by mass or less with respect to the monomer (for example, 2-pyrrolidone) from the viewpoint of improving the molecular weight. Preferably, 0.05 mass% or more and 0.10 mass% or less are more preferable.

The ring-opening polymerization is preferably performed in the presence of an acyl compound from the viewpoint of reactivity.
Examples of the acyl compound include carboxylic acid halides, carboxylic acid anhydrides, and carboxylic acid esters. Of these, carboxylic acid halides and carboxylic acid esters are preferred.
Examples of the carboxylic acid halide include carboxylic acid chloride, carboxylic acid fluoride, carboxylic acid bromide, and the like. Among these, carboxylic acid chloride is preferable. Examples of the carboxylic acid chloride include benzoyl chloride.
Moreover, as said acyl compound, the carboxylic acid type compound containing the structure derived from 2-pyrrolidone is preferable. Examples of such acyl compounds include N-acyl-2-pyrrolidone. Examples of the N-acyl-2-pyrrolidone include 1-acetyl-2-pyrrolidone.

  There is no restriction | limiting in particular as the usage-amount of the said acyl compound in the said ring-opening polymerization, Although it can select suitably according to the objective, 0.001 mass% or more and 10 mass% or less are with respect to the said 2-pyrrolidone. Preferably, 0.01 mass% or more and 1 mass% or less are more preferable, and 0.03 mass% or more and 0.08 mass% or less are especially preferable.

  The ring-opening polymerization is preferably performed in the presence of a compressive fluid because the polymerization time can be shortened.

  As a result of intensive studies, the inventors have added a compressive fluid to the mixture of 2-pyrrolidone and polyamide 4 composition, so that the reaction proceeds uniformly, the reaction becomes faster, and the polyamide after the reaction 4 It has been found that the composition can be easily taken out.

  In the ring-opening polymerization, an additive may be added as necessary. Examples of additives include surfactants, antioxidants, stabilizers, antifogging agents, UV absorbers, pigments, colorants, inorganic particles, various fillers, thermal stabilizers, flame retardants, crystal nucleating agents, antistatic agents Agents, surface wetting improvers, incineration aids, lubricants, natural products, mold release agents, plasticizers, and the like. If necessary, a polymerization terminator (benzoic acid, hydrochloric acid, phosphoric acid, metaphosphoric acid, acetic acid, lactic acid, etc.) can be used after the polymerization reaction. Although the compounding quantity of the said additive changes with purposes and the kind of additive to add, Preferably it is 0 to 5 mass parts with respect to 100 mass parts of polymers.

As the stabilizer, epoxidized soybean oil, carbodiimide and the like are used.
Examples of the antioxidant include 2,6-di-t-butyl-4-methylphenol and butylhydroxyanisole.
Examples of the antifogging agent include glycerin fatty acid ester and monostearyl citrate.
As the filler, 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, titanium oxide, carbon black, ultramarine blue and the like are used.

  Further, a ring-opening polymerizable monomer other than 2-pyrrolidone (for example, other lactam) may be added to form a copolymer.

<Compressive fluid>
Next, the compressive fluid used in the manufacturing method of this embodiment 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” in the present embodiment is a fluid in the phase diagram represented in FIG. 1 when it exists in any one of the areas (1), (2), and (3) shown in FIG. Means.

  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. Note that when the fluid exists in the region (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. In addition, the liquid is formed when the fluid is present in the region (2). In the present embodiment, the fluid is obtained by compressing a substance in a gaseous state at normal temperature (25 ° C.) and normal pressure (1 atm). Represents liquefied gas. Further, when the fluid 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).

  The substance that can be used as the compressive fluid is not particularly limited, and examples thereof include a compressive fluid containing nitrogen dioxide, ether, or hydrocarbon, or nitrogen. Carbon dioxide is preferred in terms of reactivity. These compressive fluids may be used alone or in combination of two or more.

<Polymerization reactor>
Then, the polymerization reaction apparatus used for manufacture of the polyamide 4 composition in this embodiment is demonstrated using FIG.3 and FIG.4. First, the polymerization reaction apparatus 100 will be described with reference to FIG. FIG. 3 is a system diagram showing an example of a polymerization process. When 2-pyrrolidone is anionically polymerized by a conventional production method, the polymer product is solidified during the reaction, and thus the polymer cannot be produced continuously. According to the manufacturing method of this embodiment, for example, by using the polymerization reaction apparatus 100, a polymer can be continuously manufactured.

  The polymerization reaction apparatus 100 includes a supply unit 100a for supplying a raw material such as 2-pyrrolidone and a compressive fluid, and a polymerization reaction apparatus main body 100b as an example of a continuous polymerization apparatus for polymerizing 2-pyrrolidone supplied by the supply unit 100a. Have 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 is connected to the mixing device 9, the liquid feed pump 10, the reaction vessel 13, the 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. In the present embodiment, an apparatus for mixing a compressive fluid and raw materials or polymers to dissolve or melt the raw materials is referred to as a “mixing apparatus”. In the present embodiment, “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. Further, “dissolving” means that the raw material is dissolved in the compressive fluid.

  The tank 1 of the supply unit 100a stores 2-pyrrolidone. The tank 3 stores, for example, a solid (powder or granular) among acyl compounds, carbonates, and additives. The tank 5 stores, for example, a liquid one of acyl compounds, carbonates, and additives. The tank 7 stores a compressible fluid. The tank 7 may store a gas (gas) or a solid that becomes a compressible fluid in the course of being supplied to the mixing device 9 or heated or pressurized in the mixing device 9. In this case, the gas or solid stored in the tank 7 is heated or pressurized to be in the state (1), (2), or (3) in the phase diagram of FIG. .

  The measuring feeder 2 measures 2-pyrrolidone stored in the tank 1 and continuously supplies it to the mixing device 9. The weighing feeder 4 measures the solid stored in the tank 3 and continuously supplies it to the mixing device 9. The metering pump 6 measures the liquid stored in the tank 5 and continuously supplies it to the mixing device 9. The metering pump 8 continuously supplies the compressive fluid stored in the tank 7 to the 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. That is, each material may be supplied intermittently or intermittently as long as the ring-opened polymer is continuously obtained. Further, when the acyl compound, the carbonate, and the additive are all solid, the polymerization reaction apparatus 100 may not include the tank 5 and the metering pump 6. Similarly, when the acyl compound, the carbonate, and the additive are all 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. Moreover, each apparatus of the mixing apparatus 9 of the polymerization reaction apparatus, the liquid feed pump 10, and the reaction vessel 13 has a tubular member that allows the raw materials and the like to pass therethrough.

  The mixing device 9 of the polymerization reaction device main body 100b continuously feeds raw materials such as 2-pyrrolidone, carbonate, and additive supplied from each tank (1, 3, 5) and a compressive fluid supplied from the tank 7. It is an apparatus having a pressure resistant container for bringing the raw material into contact with each other. In the mixing device 9, the raw material is melted or dissolved by contacting the raw material and the compressive fluid. When 2-pyrrolidone is dissolved, a fluid phase is formed. When melted, a molten phase is formed. In order to proceed the reaction uniformly, it is preferable that either a molten phase or a fluid phase is formed. . Moreover, it is preferable to melt 2-pyrrolidone in order to advance the reaction in a state where the ratio of raw materials to the compressive fluid is high. In this embodiment, by continuously supplying the raw material and the compressive fluid, the raw material such as 2-pyrrolidone and the compressive fluid are continuously brought into contact at a constant concentration ratio in the mixing device 9. Can do. Thereby, the raw material can be efficiently dissolved or melted.

  The shape of the container of the mixing device 9 may be a tank type or a cylindrical shape, but a cylindrical shape 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 mixing device 9, an inlet 9 a for introducing the compressive fluid supplied from the tank 7 by the metering pump 8, an inlet 9 b for introducing 2-pyrrolidone supplied from the tank 1 by the metering feeder 2, An inlet 9c for introducing the powder supplied from the tank 3 by the metering feeder 4 and an inlet 9d for introducing the liquid supplied from the tank 5 by the metering pump 6 are provided. In this embodiment, each introduction port (9a, 9b, 9c, 9d) is comprised by the coupling which connects the container of the 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, T, and outlets are used. The mixing device 9 has a heater 9e for heating each supplied raw material and compressive fluid. Furthermore, the mixing device 9 may have a stirring device that stirs the raw materials, the compressive fluid, and the like. When the 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 each other or overlapping each other, and a helical stirring element meshing with each other. A kneader having a static mixer, a static mixer or the like 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 mixing device 9 does not have a stirring device, a pressure-resistant pipe is preferably used as the mixing device 9. In this case, it is possible to reduce the installation space of the polymerization reaction apparatus 100 or improve the layout flexibility by arranging the pressure-resistant piping in a spiral shape or by bending it. In addition, when the mixing apparatus 9 does not have a stirring apparatus, in order to mix each material in the mixing apparatus 9 reliably, it is preferable that 2-pyrrolidone supplied to the mixing apparatus 9 is liquefied beforehand.

  The liquid feed pump 10 sends each raw material dissolved or melted by the mixing device 9 to the reaction vessel 13. The tank 11 stores an acyl compound. The metering pump 12 measures the acyl compound stored in the tank 11 and supplies it to the reaction vessel 13.

  The reaction vessel 13 mixes each dissolved or melted raw material fed by the feed pump 10 and the acyl compound supplied by the metering pump 12 to continuously ring-open polymerization 2-pyrrolidone. This is a pressure-resistant container. 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 mixing device 9 into the vessel, and an introduction port 13b for introducing the acyl compound 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, T, and outlets are used. Note that the reaction vessel 13 may be provided with a gas outlet for removing evaporated substances. The reaction vessel 13 has a heater 13c 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 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. When the raw materials containing the catalyst are sufficiently mixed in advance, a static mixer that performs multi-stage splitting and combining (merging) of the flow by a guide device can also be applied to the stirring device. As static mixers, those disclosed in JP-B-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, the contents of which are hereby incorporated by reference.

  When the reaction vessel 13 does not have a stirrer, pressure-resistant piping is preferably used as the reaction vessel 13. In this case, it is possible to reduce the installation space of the polymerization reaction apparatus 100 or improve the layout flexibility by arranging the pressure-resistant piping in a spiral shape or by bending it.

  Although FIG. 3 shows an example in which one reaction vessel 13 is provided, two or more reaction vessels 13 may 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.

  In general, 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 seems to be due to the instability due to the mixing of the raw material having a melt viscosity of several poise to several tens of poise and the 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 dissolved or melted in the compressive fluid, it becomes possible to reduce the viscosity difference in the system, so the number of stages is reduced compared to the conventional polymerization reaction apparatus. It becomes possible.

The metering pump 14 sends the polymer product P 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, a pressure adjusting valve can be used instead of the metering pump 14.
Moreover, you may adjust the timing which adds heat and stirring to each raw material and a compressive fluid with the reaction container 13 so that each raw material may fuse | melt efficiently. In this case, after bringing each raw material and the compressive fluid into contact with each other, heat or stirring may be applied, or heat or stirring may be applied while bringing each raw material into contact with the compressive fluid. Alternatively, 2-pyrrolidone and the compressive fluid may be brought into contact after 2-pyrrolidone is melted by applying heat equal to or higher than the melting point.

  Next, a polymerization reaction apparatus 200 used in a batch process will be described with reference to FIG. FIG. 4 is a system diagram showing an example of a batch polymerization process. In the system diagram of FIG. 4, the polymerization reaction device 200 includes a tank 21, a metering pump 22, an addition pot 25, a reaction vessel 27, and valves (23, 24, 26, 28, 29). . Each of the above devices is connected as shown in FIG. Further, the pipe 30 is provided with joints (30a, 30b).

  The tank 21 stores a compressible fluid. The tank 21 may store a gas (gas) or a solid that becomes a compressible fluid by being heated and pressurized in a supply path supplied to the reaction container 27 or in the reaction container 27. In this case, the gas or solid stored in the tank 21 is heated or pressurized to be in the state (1), (2), or (3) in the phase diagram of FIG. .

  The metering pump 22 supplies the compressive fluid stored in the tank 21 to the reaction vessel 27 at a constant pressure and flow rate. The addition pot 25 stores carbonate added to the raw material in the reaction vessel 27. The valves (23, 24, 26, 29) open and close each of them, thereby supplying the compressive fluid stored in the tank 21 to the reaction vessel 27 via the addition pot 25 and the addition pot 25. The route for supplying the reaction vessel 27 without going through is switched.

  The reaction vessel 27 contains 2-pyrrolidone and an acyl compound in advance before starting the polymerization. In the reaction vessel 27, 2-pyrrolidone and acyl compound stored in advance, the compressive fluid supplied from the tank 21, and the catalyst supplied from the addition pot 25 are brought into contact with each other to cause ring-opening polymerization of 2-pyrrolidone. This is a pressure-resistant container. The reaction vessel 27 may be provided with a gas outlet for removing the evaporated material. The reaction vessel 27 has a heater for heating the raw materials and the compressive fluid. Furthermore, the reaction vessel 27 has a stirring device for stirring 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 28 is opened after completion of the polymerization reaction to discharge the polymer product P in the reaction vessel 27.

<< Polymer production method >>
Subsequently, the raw material, the compressive fluid, and a polymer production method using the polymerization reaction apparatus 100 will be described. According to the polymer production method of this embodiment, 2-pyrrolidone and a compressive fluid are brought into contact with each other to melt or dissolve 2-pyrrolidone, and then in the presence of the basic organometallic catalyst and the cocatalyst, Ring-opening polymerization of pyrrolidone.

  First, each metering feeder (2, 4), metering pump 6, metering pump 8 is activated, 2-pyrrolidone in each tank (1, 3, 5, 7), compressible fluid, carbonate and as needed The acyl compound, which is an optional component, and the additive are continuously fed to the mixing device 9. The raw material and the compressive fluid supplied from each device are continuously introduced into the pipe of the 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 melted in advance and stored in the tank 5 in a liquid state and introduced into the pipe of the 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 amount ratio of 2-pyrrolidone, acyl compound, carbonate, and additive. The The total mass (feed rate of raw material, (g / min)) of each raw material supplied per unit time by the measuring feeder (2, 4) and the measuring pump 6 is based on the desired polymer physical properties, reaction time, etc. Adjusted. Similarly, the mass of the compressive fluid supplied per unit time by the metering pump 8 (supply rate of compressive fluid, (g / min)) is adjusted based on desired polymer properties, reaction time, and the like. The ratio between the supply speed of the compressive fluid and the supply speed of the raw material (the supply speed of the raw material / the supply speed of the compressive fluid, the feed ratio) is not particularly limited and can be appropriately selected according to the purpose. 1 or more is preferable, 3 or more is more preferable, 5 or more is further preferable, and 10 or more is particularly preferable. Moreover, there is no restriction | limiting in particular about the upper limit of feed ratio, Although it can select suitably according to the objective, 1,000 or less are preferable, 100 or less are more preferable, and 50 or less are especially preferable.

  By setting the feed ratio to 1 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 product (so-called solid content concentration) is high. proceed. The solid content concentration in the polymerization system at this time is larger than the solid content concentration of the polymerization system when a small amount of 2-pyrrolidone is dissolved in the overwhelming amount of compressive fluid in the conventional production method for polymerization. Different. The production method of this embodiment is characterized in that the polymerization reaction proceeds efficiently and stably even in a polymerization system having a high solid content concentration. In this embodiment, the feed ratio may be less than 1. Even in this case, there is no problem in the quality of the polymer product to be obtained, but the economical efficiency is inferior. On the other hand, if the feed ratio exceeds 1,000, the compressive fluid may have insufficient ability to melt 2-pyrrolidone, and the intended reaction may not proceed uniformly.

  Each raw material and compressive fluid are continuously introduced into the tube of the mixing device 9 so that they are in continuous contact with each other. Thereby, in the mixing apparatus 9, raw materials, such as 2-pyrrolidone, an acyl compound, carbonate, an additive, are mixed, and 2-pyrrolidone melts or melt | dissolves. When the 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 tube of the reaction vessel 13 are preferably controlled to a temperature and pressure above the triple point of the compressive fluid. This pressure is controlled by, for example, the pump flow rate, pipe diameter, pipe length, pipe shape, and the like. This control is performed by adjusting the output of the heater 9e of the mixing device 9 or the supply speed of the compressive fluid.

  In this embodiment, the temperature at which 2-pyrrolidone is melted or dissolved may be a temperature equal to or lower than the melting point of 2-pyrrolidone at normal pressure. This is considered to be due to the high pressure in the mixing device 9 in the presence of the compressive fluid, and the melting point of 2-pyrrolidone being lower than the melting point at normal pressure. For this reason, even if the amount of compressive fluid relative to 2-pyrrolidone is small, 2-pyrrolidone melts or dissolves in the mixing device 9.

  You may adjust the timing which applies heat and stirring to each raw material and a compressive fluid with the mixing apparatus 9 so that each raw material may mix efficiently. 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. Moreover, in order to mix more reliably, for example, 2-pyrrolidone and the compressive fluid may be brought into contact after 2-pyrrolidone is heated in advance to a melting point or higher. In each of the above embodiments, for example, when the mixing device 9 is a biaxial mixing device, the screw arrangement, the arrangement of the inlets (9a, 9b, 9c, 9d), and the temperature of the heater 9e are appropriately set. Is realized.

  In this embodiment, an additive is supplied to the mixing device 9 separately from 2-pyrrolidone, but the additive may be supplied together with 2-pyrrolidone. Moreover, you may supply an additive after a polymerization reaction. In this case, after taking out the obtained polymer product from the reaction vessel 13, the additive can be added while kneading.

  The raw materials mixed by the mixing device 9 are fed by the feed pump 10 and supplied to the reaction vessel 13 from the inlet 13a.

  Each raw material is heated to a predetermined temperature (polymerization reaction temperature) by the heater 13c while being sufficiently stirred or fed by the stirring device of the reaction vessel 13 as necessary. Thereby, 2-pyrrolidone undergoes ring-opening polymerization in the reaction vessel 13 (polymerization step). The temperature at the time of ring-opening polymerization of 2-pyrrolidone (polymerization reaction temperature) is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 40 ° C. or higher and 200 ° C. or lower, preferably 50 ° C. or higher. More preferably, the temperature is 150 ° C. If the polymerization reaction temperature is lower than 40 ° C., the reaction rate may decrease. On the other hand, if the polymerization reaction temperature exceeds 200 ° C., side reactions may occur. However, depending on the combination of the compressive fluid, 2-pyrrolidone and acyl compound, 2-pyrrolidone may be subjected to ring-opening polymerization at a temperature other than the above range. The polymerization reaction temperature is controlled by, for example, a heater provided in the polymerization reaction apparatus or external heating.

  The polymer product P that has finished 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 operate at a constant pressure in the polymerization system filled with compressible fluid to obtain a uniform polymer product. 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 measuring feeders (2, 4), and the measuring pumps (6, 8) in the mixing device 9 are controlled so that the back pressure of the liquid feeding 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.

  The catalyst remaining in the polymer product obtained by this embodiment is removed as necessary. The removing method is not particularly limited, and examples thereof include distillation under reduced pressure and extraction using a compressible fluid. 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 35 ° C. or higher and 100 ° C. or lower, and the catalyst can be removed at a temperature lower than the temperature at which the polymer product is depolymerized. 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.

  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, the melting of 2-pyrrolidone is promoted, and the polymerization reaction can proceed uniformly and quantitatively. When dimethyl ether is used as a compressible fluid, the pressure is 2.7 MPa or more, preferably 5 MPa or more, more preferably 5.4 PMa or more of the critical pressure, considering the efficiency of the reaction, the polymer conversion rate, and the like. .

  In the production method of the present embodiment, the conversion rate obtained from GPC to the polyamide 4 composition by ring-opening polymerization such as 2-pyrrolidone is 50% or more, preferably 80% or more. In this embodiment, the conversion rate to the polyamide 4 composition refers to the monomer (for example, 2-pyrrolidone) that contributed to the generation of the polymer relative to the monomer (for example, 2-pyrrolidone) as a raw material and the cyclic oligomer of the by-product. Mean percentage of quantity. The amount of monomer that contributed to the production of the polyamide 4 composition is obtained by subtracting the amount of unreacted monomer (for example, 2-pyrrolidone) from the amount of the produced polyamide 4 composition.

  The weight average molecular weight of the polyamide 4 composition obtained by this embodiment is 300,000 or more.

Unreacted monomer can be removed by contacting with a supercritical fluid containing carbon dioxide.
By contacting with a supercritical fluid containing carbon dioxide, only unreacted monomers can be removed while the carbonate remains in the polyamide 4 composition.

<Amount of monomer and oligomer>
According to the manufacturing method of the present embodiment, by using a compressive fluid, as described above, a polymerization reaction at a low temperature is possible, so that the depolymerization reaction can be significantly suppressed as compared with the conventional melt polymerization. . Thereby, the monomer amount remaining in the polyamide 4 composition obtained by the production method of the present embodiment is 5,000 mass ppm or less, preferably 4,000 mass ppm or less. Examples of the method for measuring the residual monomer amount include the methods described in the examples below.

<< Use of polyamide 4 composition >>
The polyamide 4 composition obtained by the production method of the present embodiment is produced by a production method that does not use an organic solvent and has a small amount of residual monomer, and thus is excellent in safety and stability. The organic solvent refers to an organic compound that is liquid at normal temperature (25 ° C.) and normal pressure, and is different from a compressive fluid. The polyamide 4 composition obtained by the production method of the present embodiment is formed into, for example, particles, films, sheets, molded products, fibers, etc., for example, daily necessities, industrial materials, agricultural products, sanitary materials, pharmaceuticals, Widely used in applications such as cosmetics, electrophotographic toner, packaging materials, electrical equipment materials, home appliance housings, automotive materials.

<< Effects of Embodiment >>
In the polyamide 4 composition obtained by the conventional melt polymerization method, it was necessary to add a large amount of carbonate after polymerization to improve molding processability after removing unreacted monomers. According to the polymerization method of this embodiment, a polyamide 4 composition containing a small amount of carbonate can be obtained by polymerization in a compressive fluid.
In addition, it is possible to provide a polymer that is excellent in terms of low cost, low environmental load, energy saving, and resource saving and excellent in molding processability and thermal stability.
In the ring-opening polymerization of 2-pyrrolidone, a polymer (polyamide 4 composition) can be obtained continuously at a relatively low temperature (below the melting point of the produced polymer) and in a short time.
In the polymerization method using an organic solvent, in order to use the obtained polyamide 4 composition as a solid, a step of removing the solvent is required. In the polymerization method of this embodiment, since a compressive fluid is used, no waste liquid or the like is generated, and the dried polyamide 4 composition is obtained in a single step, so that the drying step can be simplified or omitted.

  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. In addition, the polymer obtained by the Example and the comparative example was evaluated as follows. The results are shown in Table 1-1 and Table 1-2.

<Measurement of molecular weight of polymer>
The measurement was carried out under the following conditions by GPC (Gel Permeation Chromatography).
-Equipment: GPC-8020 (manufactured by Tosoh Corporation)
Column: GMH _HR- M (manufactured by Tosoh Corporation)
・ Temperature: 40 ℃
Solvent: HFIP (hexafluoroisopropanol)
Flow rate: 0.2 mL / min 1 mL of a polymer having a concentration of 0.05% by mass was injected, and using a molecular weight calibration curve prepared by a monodisperse polymethyl methacrylate standard sample from the molecular weight distribution of the polymer measured under the above conditions, The weight average molecular weight Mw of the polymer is calculated.

<Measurement of residual monomer amount>
It calculated | required from the peak area ratio of a polymer and a monomer obtained at the time of the molecular weight measurement of a polymer.

<Polymer molding>
The obtained polymer composition was stored at a temperature of 22 ° C. and a humidity of 65% for 1 month, and then a film (100 μm) was formed by hot pressing (temperature 220 ° C., pressure 30 MPa, molding holding time 1 minute).

<Tensile strength>
The tensile strength was measured according to JIS K 7127. As the measurement sample, the molded film was used.

Example 1
The following materials were charged into a flask and reacted at 50 ° C. for 48 hours to obtain a polyamide 4 composition.
2-pyrrolidone: 20g
Potassium carbonate: 0.02g
1-acetyl-2-pyrrolidone: 0.01 g
The materials used were those manufactured by Junsei Chemical.

(Example 2)
Polymerization was performed using the polymerization reaction apparatus 200 of FIG. The structure of the polymerization reaction apparatus 200 is shown.
Tank 21: Carbon dioxide (CO ₂ ) gas cylinder Addition pot 25: A 1/4 inch SUS316 pipe was sandwiched between valves (24, 29) and used as an addition pot. In advance, potassium carbonate was charged as a catalyst.
Reaction vessel 27: 2-pyrrolidone as a ring-opening polymerizable monomer and 1-acetyl-2-pyrrolidone are mixed in advance in a 100 mL SUS316 pressure vessel [2-pyrrolidone: 1-acetyl-2-pyrrolidone = 20: 0.01 (mass ratio)].

By operating the metering pump 22 and opening the valves (23, 26), the CO ₂ stored in the tank 21 was supplied to the reaction vessel 27 without going through the addition pot 25. The internal temperature of the reaction vessel 27 was set to 30 ° C., and CO ₂ was charged until the pressure at that time reached 8 MPa to melt 2-pyrrolidone. When the inside of the reaction vessel 27 reaches 50 ° C., the valves (24, 29) are opened, and potassium carbonate in the addition pot 25 is 0.1 mass relative to 2-pyrrolidone in the reaction vessel 27. % Was supplied. Thereafter, the temperature was increased and the pressure was increased, and 2-pyrrolidone was polymerized in the reaction vessel 27 for 120 minutes after reaching 50 ° C. and 10 MPa. After completion of the reaction, the valve 28 was opened, and the polymer product (polyamide 4 composition) in the reaction vessel 27 was taken out.

Example 3
In Example 2, the amount of potassium carbonate in the reaction vessel was changed to 0.01% by mass with respect to 2-pyrrolidone, and the polymerization time was changed to 4 hours. A composition was prepared.

Example 4
In Example 2, polyamide 4 was changed in the same manner as in Example 2 except that the amount of potassium carbonate in the reaction vessel was changed to 0.05% by mass with respect to 2-pyrrolidone and the polymerization time was changed to 3 hours. A composition was prepared.

(Example 5)
In Example 4, a polyamide 4 composition was prepared in the same manner as in Example 4 except that potassium carbonate in the reaction vessel was changed to sodium carbonate.

(Example 6)
A polyamide 4 composition was prepared in the same manner as in Example 4 except that 2-pyrrolidone was changed to a mixture of 2-pyrrolidone and 2-azetidinone (mixing mass ratio = 1: 1) in Example 4.

(Comparative Example 1)
In Example 1, a polyamide 4 composition was produced in the same manner as in Example 1 except that the amount of potassium carbonate was changed to 0.04 g.

(Comparative Example 2)
In Example 2, the amount of potassium carbonate in the reaction vessel was changed to 0.005% by mass with respect to 2-pyrrolidone, and the polymerization time was changed to 4 hours. A composition was prepared.

(Comparative Example 3)
In Example 2, polyamide 4 was changed in the same manner as in Example 2 except that the amount of potassium carbonate in the reaction vessel was changed to 0.05% by mass with respect to 2-pyrrolidone and the polymerization time was changed to 1 hour. A composition was prepared.

(Comparative Example 4)
In Example 2, the amount of potassium carbonate in the reaction vessel was changed to 0.005% by mass with respect to 2-pyrrolidone, and the polymerization time was changed to 12 hours. A composition was prepared.

(Comparative Example 5)
In Example 2, the amount of potassium carbonate in the reaction vessel was changed to 0.05% by mass with respect to 2-pyrrolidone, and the polymerization time was changed to 2 hours. A composition was prepared.

  Since the polyamide 4 compositions of Comparative Examples 2 and 4 did not melt at 220 ° C., the film was formed at a hot press temperature of 250 ° C.

The amount of carbonate in Table 1-1 and Table 1-2 is the content (% by mass) of carbonate in the obtained resin (polyamide 4 composition).

Aspects of the present invention are as follows, for example.
<1> The polymethylmethacrylate conversion weight average molecular weight measured by gel permeation chromatography is 300,000 or more, the residual monomer amount is 5,000 mass ppm or less, and the carbonate content is 0.01 mass. % To 0.10% by mass of the polyamide 4 composition.
<2> The polyamide 4 composition according to <1>, wherein the carbonate is potassium carbonate.
<3> The polyamide 4 composition according to any one of <1> to <2>, wherein the polymethylmethacrylate conversion weight average molecular weight measured by gel permeation chromatography is 500,000 or more.
<4> A method for producing a polyamide 4 composition for producing the polyamide 4 composition according to any one of <1> to <3>,
It is a method for producing a polyamide 4 composition characterized by ring-opening polymerization of 2-pyrrolidone in the presence of a carbonate.
<5> The method for producing a polyamide 4 composition according to <4>, wherein the carbonate is potassium carbonate.
<6> The method for producing a polyamide 4 composition according to any one of <4> to <5>, wherein the ring-opening polymerization is performed in the presence of an acyl compound.
<7> The method for producing a polyamide 4 composition according to any one of <4> to <6>, wherein the ring-opening polymerization is performed in a compressive fluid.
<8> The method for producing a polyamide 4 composition according to <7>, wherein the compressive fluid is carbon dioxide.

1, 3, 5, 7, 11, Tank 2, 4, Metering feeder 6, 8, 12, 14, Metering pump 9, Mixing device 9a Inlet 9b Inlet 10 Feed pump 13 Reaction vessel 13a Inlet 13b Inlet 15 Extrusion cap 21 Tank 22 Metering pump 23 Valve 24 Valve 25 Addition pot 26 Valve 27 Pressure vessel 28 Valve 30 Pipe 100 Polymerization reactor 200 Polymerization reactor P Polymer product

US Pat. No. 2,739,959 Japanese Patent Publication No. 36-10843 Japanese Patent Publication No. 47-26678 JP-A-5-59167 JP 2002-265596 A International Publication No. 2012/157576 Pamphlet

Claims (8)

  The polymethylmethacrylate conversion weight average molecular weight measured by gel permeation chromatography is 300,000 or more, the residual monomer amount is 5,000 mass ppm or less, and the carbonate content is 0.01 mass% or more and 0. Polyamide 4 composition characterized by being 10% by mass or less.   The polyamide 4 composition according to claim 1, wherein the carbonate is potassium carbonate.   The polyamide 4 composition according to any one of claims 1 to 2, wherein the polymethylmethacrylate conversion weight average molecular weight measured by gel permeation chromatography is 500,000 or more. A method for producing a polyamide 4 composition for producing the polyamide 4 composition according to any one of claims 1 to 3,
A process for producing a polyamide 4 composition comprising ring-opening polymerization of 2-pyrrolidone in the presence of a carbonate.   The method for producing a polyamide 4 composition according to claim 4, wherein the carbonate is potassium carbonate.   The method for producing a polyamide 4 composition according to any one of claims 4 to 5, wherein the ring-opening polymerization is performed in the presence of an acyl compound.   The method for producing a polyamide 4 composition according to any one of claims 4 to 6, wherein the ring-opening polymerization is performed in a compressive fluid.   The method for producing a polyamide 4 composition according to claim 7, wherein the compressive fluid is carbon dioxide.