(METH)acrylic polymer regeneration apparatus, (METH)acrylic polymer regeneration method, and method for producing monomer having (METH)acrylic group

Abstract

To provide a (meth)acrylic polymer regeneration apparatus capable of recovering a monomer having a (meth)acryloyl group with high purity, a (meth)acrylic polymer regeneration method, and a production method for a (meth)acrylic acid ester.SOLUTION: A (meth)acrylic polymer regeneration apparatus comprises a pyrolysis section that performs pyrolysis of a (meth)acrylic polymer to obtain a pyrolysis gas, a collection section that collects impurities contained in the pyrolysis gas, and a gas treatment section that treats the pyrolysis gas after the impurities have been collected in the collection section, wherein the collection section collects impurities by at least one collection mechanism selected from inertial impaction, interception, diffusion, and electrostatic action.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an apparatus for recycling a (meth)acrylic polymer, a method for recycling a (meth)acrylic polymer, and a method for producing a monomer having a (meth)acrylic group. [Background technology]

[0002] (Meth)acrylic polymers obtained by polymerizing monomers having a (meth)acrylic group have excellent transparency and weather resistance, and are therefore widely used as materials for components constituting automobile parts, signboards, display devices, etc.

[0003] Along with the recent rise in resource prices and growing awareness of environmental issues, there has been a growing trend to collect and recycle products (molded articles) containing (meth)acrylic polymers used for various applications as described above.

[0004] Methods for recycling molded articles containing (meth)acrylic polymers include, for example, material recycling, in which recovered molded articles are subjected to a molding process again to produce new molded articles; chemical recycling, in which recovered molded articles are thermally decomposed (depolymerized) to recover monomers having (meth)acrylic groups, and new molded articles are produced using these monomers; and thermal recycling, in which recovered molded articles are combusted and the resulting combustion energy is used as a direct heat source or as electricity converted by a generator.

[0005] (Meth)acrylic polymers are suitable for chemical recycling because the pyrolysis product, the monomer, can be recovered in high yield by heating at a relatively low temperature of about 300 to 500°C.

[0006] For example, Patent Document 1 describes a method for recovering a monomer having a (meth)acrylic group, which comprises heating a resin product containing a (meth)acrylic polymer in a heating furnace to obtain a gaseous pyrolysate (hereinafter also referred to as pyrolysis gas) and then liquefying the gaseous pyrolysate by cooling and purifying the liquefied pyrolysate by distillation. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-321571 Summary of the Invention [Problem to be solved by the invention]

[0008] From the viewpoint of promoting the widespread use of a recycling system for (meth)acrylic polymers, one of the important issues is to increase the purity of monomers having a (meth)acrylic group recovered by recycling. In view of the above circumstances, an object of one embodiment of the present disclosure is to provide a (meth)acrylic polymer recycling device capable of recovering a monomer having a (meth)acrylic group with high purity, a (meth)acrylic polymer recycling method, and a (meth)acrylic acid ester manufacturing method. [Means for solving the problem]

[0009] Means for solving the above problems include the following embodiments. <1> a pyrolysis section that performs pyrolysis of a (meth)acrylic polymer to obtain a pyrolysis gas; a collection unit that collects impurities contained in the pyrolysis gas; a gas treatment unit that treats the pyrolysis gas after impurities have been collected by the collection unit, The (meth)acrylic polymer recycling device, wherein the collection section collects impurities by at least one collection mechanism selected from inertial impaction, interception, diffusion, and electrostatic action. <2> The pyrolysis gas supplied to the collection section is in a state in which droplets containing impurities are present in a gas containing a monomer having a (meth)acrylic group. <1> The playback device described in <3> The impurities collected in the collection section include components that condense at a temperature higher than that of the monomer having a (meth)acrylic group. <1> or <2> The playback device described in <4> Further provided is a partial condensation unit that condenses at least a portion of the impurities contained in the pyrolysis gas. <1> ~ <3> 10. The playback device according to claim 9, wherein: <5> The partial condensation section is disposed between the thermal decomposition section and the collection section. <4> The playback device described in <6> Further provided is a second collection section that collects impurities contained in the pyrolysis gas, The second collection section collects impurities by gravity. <1> ~ <5> 10. The playback device according to claim 9, wherein: <7> Further comprising a waste liquid treatment unit connected to the collection unit, <1> ~ <6> 10. The playback device according to claim 9, wherein: <8> The gas treatment unit includes at least one selected from the group consisting of a cooling unit that cools the pyrolysis gas and a purification unit that purifies the pyrolysis gas. <1> ~ <7> 10. The playback device according to claim 9, wherein: <9> a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a capturing step of capturing impurities contained in the pyrolysis gas; a gas treatment step for treating the pyrolysis gas after the impurities have been collected in the collection step, The method for regenerating a (meth)acrylic polymer, wherein the collection step involves collecting impurities by at least one collection mechanism selected from inertial impaction, interception, diffusion, and electrostatic action. <10> a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a capturing step of capturing impurities contained in the pyrolysis gas; a gas treatment step for treating the pyrolysis gas after the impurities have been collected in the collection step, A method for producing a monomer having a (meth)acrylic group, wherein the collection step collects impurities by at least one collection mechanism selected from inertial impaction, interception, diffusion, and electrostatic action. [Effects of the Invention]

[0010] According to the present disclosure, there are provided a (meth)acrylic polymer recycling device capable of recovering monomers having a (meth)acrylic group with high purity, a (meth)acrylic polymer recycling method, and a (meth)acrylic acid ester manufacturing method. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of a playback device. [Figure 2A] FIG. 2 is a schematic diagram showing an example of the configuration of a collection unit. [Figure 2B] FIG. 2 is a schematic diagram showing an example of the configuration of a collection unit. [Figure 2C] FIG. 2 is a schematic diagram showing an example of the configuration of a collection unit. DETAILED DESCRIPTION OF THE INVENTION

[0012] First Embodiment The first embodiment of the present disclosure is a pyrolysis section that performs pyrolysis of a (meth)acrylic polymer to obtain a pyrolysis gas; a collection unit that collects impurities contained in the pyrolysis gas; a gas treatment unit that treats the pyrolysis gas after impurities have been collected by the collection unit, The collection unit is a (meth)acrylic polymer regeneration device that collects impurities by at least one collection mechanism selected from inertial impaction, interception, diffusion, and electrostatic action.

[0013] The recycling device of this embodiment thermally decomposes a (meth)acrylic polymer supplied to the recycling device to recover a monomer having a (meth)acrylic group. That is, the recycling device of this embodiment is used for chemical recycling of a (meth)acrylic polymer. Since the (meth)acrylic polymer used as the raw material for chemical recycling may contain materials other than the (meth)acrylic polymer, the pyrolysis gas obtained in the pyrolysis section may contain components other than the monomer having a (meth)acrylic group as impurities. The regeneration device of the present disclosure is equipped with a collection section that collects impurities (more specifically, mist-formed impurities) contained in the pyrolysis gas obtained in the pyrolysis section, thereby enabling the recovery of monomers having (meth)acrylic groups with high purity.

[0014] Although one method for increasing the purity of a monomer having a (meth)acrylic group is to carry out a known purification process (such as distillation) in a gas treatment section that treats pyrolysis gas, it is desirable to reduce the amount of impurities contained in the pyrolysis gas before it is treated in the gas treatment section in order to reduce the energy consumption and equipment costs required for purification. Therefore, the regeneration device disclosed herein is useful from the viewpoint of reducing the amount of impurities contained in the pyrolysis gas before it is treated in the gas treatment section, and thus reducing the energy consumption and equipment costs required for treating the pyrolysis gas in the gas treatment section. Furthermore, impurities contained in the pyrolysis gas may cause blockage of the piping of the regeneration device. By providing the regeneration device with a collection unit, blockage of the piping due to impurities contained in the pyrolysis gas can be suppressed.

[0015] ((Meth)acrylic polymer) In the present disclosure, the term "(meth)acrylic polymer" refers to a polymer having structural units derived from a monomer having a (meth)acrylic group. In the present disclosure, "(meth)acrylic" includes acrylic, methacrylic, and combinations thereof.

[0016] The (meth)acrylic polymer may be a (meth)acrylic homopolymer or a (meth)acrylic copolymer. An example of the (meth)acrylic homopolymer is a (meth)acrylic homopolymer containing only monomer units derived from alkyl (meth)acrylate having an alkyl group having 1 to 4 carbon atoms. Examples of the (meth)acrylic copolymer include a (meth)acrylic copolymer in which the proportion of monomer units derived from alkyl (meth)acrylate having an alkyl group with 1 to 4 carbon atoms is 85% by mass or more and less than 100% by mass, and the proportion of monomer units derived from other vinyl monomers copolymerizable with the monomer units derived from alkyl (meth)acrylate having an alkyl group with 1 to 4 carbon atoms is more than 0% by mass and 15% by mass or less.

[0017] The "alkyl (meth)acrylate having an alkyl group with 1 to 4 carbon atoms" refers to a compound represented by, for example, CH2=C(CH3)COOR (wherein R is an alkyl group with 1 to 4 carbon atoms).

[0018] The vinyl monomer copolymerizable with an alkyl (meth)acrylate having an alkyl group with 1 to 4 carbon atoms is a monomer that is copolymerizable with an alkyl methacrylate having an alkyl group with 1 to 4 carbon atoms and has a vinyl group.

[0019] Examples of alkyl (meth)acrylates having an alkyl group of 1 to 4 carbon atoms include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, sec-butyl methacrylate, and isobutyl methacrylate. The alkyl methacrylate having an alkyl group of 1 to 4 carbon atoms is preferably methyl methacrylate.

[0020] Examples of vinyl monomers copolymerizable with alkyl (meth)acrylates having an alkyl group of 1 to 4 carbon atoms include methacrylate esters such as cyclohexyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, and monoglycerol methacrylate (excluding alkyl methacrylates having an alkyl group of 1 to 4 carbon atoms); methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, Examples of suitable monomers include acrylic acid esters such as 2-hydroxypropyl acrylate and monoglycerol acrylate; unsaturated carboxylic acids or anhydrides thereof such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, maleic anhydride and itaconic anhydride; nitrogen-containing monomers such as acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, diacetone acrylamide and dimethylaminoethyl methacrylate; epoxy group-containing monomers such as allyl glycidyl ether, glycidyl acrylate and glycidyl methacrylate; and styrene-based monomers such as styrene and α-methylstyrene.

[0021] The (meth)acrylic polymer may be polymethyl(meth)acrylate (PMMA or PMA), which is a polymer of methyl(meth)acrylate (MMA or MA).

[0022] The (meth)acrylic polymer supplied to the recycling device may be in the form of a molded product of the (meth)acrylic polymer. The type of molded product is not particularly limited and can be selected from known molded products such as cast molded products, extrusion molded products, and injection molded products.

[0023] The molded article of the (meth)acrylic polymer may consist of only the (meth)acrylic polymer, or may contain the (meth)acrylic polymer and a component different from the (meth)acrylic polymer. Examples of the component different from the (meth)acrylic polymer include polymers different from the (meth)acrylic polymer, such as polyvinyl chloride, polyolefin, and polyester, and additives. Examples of additives include fillers, colorants, ultraviolet inhibitors, and mold release agents.

[0024] The (meth)acrylic polymer supplied to the recycling device may be in the form of scrap or compressed material. In this disclosure, "scrap" refers to waste products collected after being used for a specific purpose, defective products and offcuts generated in the product manufacturing process, and pulverized waste products, defective products, and offcuts. "Compressed material" refers to a material obtained by compressing the material described as scrap. The scrap and compressed material may be adjusted in shape and size to be suitable for pyrolysis treatment.

[0025] The components included in the playback device of this embodiment will be described below.

[0026] (pyrolysis section) The regeneration device of this embodiment includes a thermal decomposition unit that thermally decomposes the (meth)acrylic polymer to convert it into a pyrolysis gas. In the present disclosure, the thermal decomposition of a (meth)acrylic polymer means decomposing the (meth)acrylic polymer into monomers by heating.

[0027] As the thermal decomposition section, any device having a function of thermally decomposing a (meth)acrylic polymer can be used without any particular limitation. Processes used for the thermal decomposition of (meth)acrylic polymers include a molten metal bath process, a kneader process, a fluidized bed process, a microwave process, an extruder process, and the like.

[0028] The material of the thermal decomposition section is not particularly limited, and any known material can be used without any particular limitation. When the (meth)acrylic polymer supplied to the thermal decomposition section contains chlorine and water, hydrochloric acid may be generated by the reaction between the chlorine and water. Therefore, the (meth)acrylic polymer in the thermal decomposition section or the portion that comes into contact with the thermal decomposition gas is preferably made of a material that is highly corrosion-resistant. Examples of materials that are highly corrosion-resistant include Ti, Zr, Ta, and Hastelloy (registered trademark).

[0029] The conditions for carrying out the thermal decomposition of the (meth)acrylic polymer in the thermal decomposition section are not particularly limited, and can be set in consideration of the properties, composition, etc. of the (meth)acrylic polymer to be treated.

[0030] When a microwave process is used as the thermal decomposition method, for example, microwaves are irradiated from outside the reactor to thermally decompose the (meth)acrylic polymer. Unlike conventional heating processes, the use of microwaves allows energy to be applied directly and selectively to the target object at the speed of light. Plastics such as (meth)acrylic polymers generally have low microwave absorption capacity. For this reason, a component with high microwave absorption capacity may be added to the (meth)acrylic polymer to promote thermal decomposition.

[0031] From the viewpoint of the efficiency of the thermal decomposition process, the thermal decomposition section is preferably an extruder. In this disclosure, "extruder" refers to a device equipped with a mechanism that rotates a screw arranged inside a cylindrical member (cylinder) to melt raw materials fed from the upstream side of the cylinder and transport them downstream.

[0032] The type of extruder is not particularly limited, and a known twin-screw extruder or single-screw extruder can be used. From the viewpoint of efficiently carrying out the thermal decomposition of the (meth)acrylic polymer, the extruder is preferably a twin-screw extruder such as a twin-screw co-rotating extruder or a twin-screw counter-rotating extruder. As components of the extruder such as a cylinder and a screw, known components can be used without any particular limitation.

[0033] The pressure of the extruder is preferably 0.005 MPa to 1.5 MPa, more preferably 0.01 MPa to 0.3 MPa, from the viewpoint of preventing air from leaking into the system and pyrolysis gas from leaking out of the system.

[0034] From the viewpoint of thermal decomposition efficiency, the temperature inside the cylinder of the extruder can usually be set to 400° C. to 500° C. When the target of thermal decomposition is a pure (meth)acrylic polymer, the temperature is preferably 450° C. to 470° C.

[0035] From the viewpoint of stable operation of the extruder, the screw rotation speed of the extruder can usually be set to 500 rpm to 1500 rpm. When the target of thermal decomposition is a pure (meth)acrylic polymer, it is preferably 500 rpm to 1000 rpm.

[0036] The amount of (meth)acrylic polymer fed to the extruder varies depending on the scale of the extruder, but is usually 10 kg / hour to 5,000 kg / hour. For example, when the diameter of the extruder cylinder is 47 mm, the amount is preferably 40 kg / hour to 90 kg / hour.

[0037] (Collection section) The regeneration device of this embodiment includes a collection unit. The collector captures impurities contained in the pyrolysis gas by at least one collection mechanism selected from inertial impaction, interception, diffusion, and electrostatic action. From the viewpoint of impurity capture efficiency, the collection mechanism of the collector preferably includes inertial impaction.

[0038] From the viewpoint of capturing impurities contained in the pyrolysis gas in the collection section by at least one capturing mechanism selected from inertial collision, interception, diffusion, and electrostatic action, the pyrolysis gas supplied to the collection section is preferably in the form of a mist. That is, the pyrolysis gas supplied to the collection section is preferably in a state in which it has been partially cooled and high condensation point components and the like have been liquefied to form a mist (a state in which droplets containing impurities are present in a gas containing a monomer having a (meth)acrylic group). The fact that the pyrolysis gas supplied to the collection section is in the form of a mist means that the impurities collected by the collection section include components that condense at temperatures similar to or higher than those of the monomer having a (meth)acrylic group (hereinafter also referred to as high condensation point components). In other words, this means that the collection section targets the high condensation point components contained in the pyrolysis gas. When the pyrolysis gas supplied to the collection section is in the form of a mist, the size of the droplets containing impurities may be 50 μm or less, 40 μm or less, or 30 μm or less, or 0.1 μm or more, 1 μm or more, or 5 μm or more.

[0039] The collection section may include a tank having an inlet and an outlet for the pyrolysis gas, and a collection device disposed inside the tank. The tank may house the collector and store components that do not pass through the collector (ie, impurities contained in the pyrolysis gas). The pyrolysis gas inlet and outlet may be positioned to allow the pyrolysis gas to pass through a collector within the tank.

[0040] The flow direction of the pyrolysis gas in the collection section is not particularly limited and may be the direction of gravity, horizontal, oblique, etc. The flow direction of the pyrolysis gas may be linear, or may involve rotation, bending, etc. From the viewpoint of the efficiency of capturing impurities, the flow direction of the pyrolysis gas is preferably from below to above in the direction of gravity. The positions of the inlet and outlet for the pyrolysis gas in the collection section are not particularly limited, and can be set depending on the flow direction of the pyrolysis gas. From the viewpoint of the efficiency of collecting impurities, it is preferable that the inlet for pyrolysis gas is disposed below the collector in the direction of gravity, and the outlet for pyrolysis gas is disposed above the collector in the direction of gravity.

[0041] The type of collector included in the collector is not particularly limited, and can be set depending on the state of the pyrolysis gas or impurities contained in the pyrolysis gas that is brought into contact with the collector (for example, the size of droplets of mist containing impurities).

[0042] The material of the collector is not particularly limited. From the viewpoint of heat resistance, corrosion resistance, and chemical resistance, the material of the collector is preferably metal, and more preferably stainless steel, nickel, titanium, or copper.

[0043] In some embodiments of the present disclosure, the collection unit may include a demister as a collection device. In this disclosure, a demister refers to an object (also called a wire mesh demister or mist separator) obtained by forming a wire mesh into a desired shape and size.

[0044] Collection of objects using a demister is accomplished, for example, by passing a gas containing the objects to be collected in droplet form through the demister. Specifically, droplets of the objects contained in the gas passing through the demister collide with the wires that make up the demister and are captured on the surface of the wires. When the objects repeatedly collide with the wires, the objects captured on the surface of the wires grow into larger droplets due to factors such as the aggregation of the objects due to surface tension and capillary action between the wires. Once the objects have grown to an appropriate size, they leave the surface of the demister and fall downward due to gravity. Through these processes, the components that pass through the demister are separated from the components that do not pass through the demister.

[0045] From the viewpoint of the collection efficiency by the collection section, it is preferable to partially cool the pyrolysis gas supplied to the collection section and liquefy the high condensation point components and the like into a mist. The method for turning the pyrolysis gas into a mist is not particularly limited, and the pyrolysis gas discharged from the pyrolysis section may be in a mist state, or the pyrolysis gas may be cooled to turn into a mist. The cooling method may be natural cooling of the pyrolysis gas or forced cooling of the pyrolysis gas. From the viewpoint of efficiently turning the pyrolysis gas into a mist, the step of turning the pyrolysis gas into a mist may be performed in a partial condensation section, which will be described later.

[0046] (Division part) The regeneration device may further comprise a partial condensation section. The partial condensation section cools the pyrolysis gas to a temperature equal to or higher than the condensation point of the monomer having a (meth)acrylic group and lower than the condensation point of the impurities contained in the pyrolysis gas. That is, the partial condensation section can convert the pyrolysis gas into a state in which droplets formed by condensation of impurities are present in a gas containing the monomer having a (meth)acrylic group.

[0047] The temperature of the pyrolysis gas after being cooled by the partial condensation section can be set depending on the types of components contained in the pyrolysis gas. For example, when the pyrolysis gas contains methyl (meth)acrylate as a monomer having a (meth)acrylic group, the temperature of the pyrolysis gas after being cooled by the partial condensation section is preferably 100°C to 420°C, more preferably 100°C to 300°C, and even more preferably 100°C to 200°C.

[0048] When the regeneration device includes a partial condensation section, the partial condensation section is preferably disposed between the pyrolysis section and the collection section. The partial condensation section may include, for example, a temperature adjustment mechanism for adjusting the temperature of the pyrolysis gas.

[0049] (Second collection section) The regenerator may further include a second collection unit that collects impurities contained in the pyrolysis gas by gravity. The pyrolysis gas supplied to the second collection section is preferably in a state (mist state) in which droplets containing impurities are present in a gas containing a monomer having a (meth)acrylic group. The second collection unit utilizes gravity to collect impurities, which is effective for collecting impurities that cannot be collected by at least one collection mechanism selected from inertial impaction, interception, diffusion, and electrostatic action (for example, impurities whose droplet size is too large).

[0050] The second collection unit may include, for example, a first temperature control mechanism for adjusting the temperature of the pyrolysis gas, a collection tank for introducing the pyrolysis gas, and a second temperature control mechanism for adjusting the temperature of the collected impurities. In this case, the pyrolysis gas before being introduced into the collection tank is cooled, kept warm, or heated by the first temperature control mechanism. When the pyrolysis gas whose temperature has been adjusted by the first temperature control mechanism is introduced into the collection tank, the flow rate of liquefied or solidified components contained as impurities in the pyrolysis gas decreases. This allows for more effective collection of impurities by gravity.

[0051] The temperature of the impurities collected in the collection tank is adjusted by a second temperature control mechanism to a temperature equal to or higher than the softening point of the (meth)acrylic polymer and lower than the ignition point of methyl (meth)acrylate, whereby the collected residue becomes liquid, and is separated as a liquid residue containing undecomposed components and stored in the collection tank.

[0052] (Gas processing unit) The regeneration device of the present disclosure may include a gas treatment section that treats the pyrolysis gas generated in the pyrolysis section. The method for treating the pyrolysis gas is not particularly limited and can be selected from known methods. As a means for treating the pyrolysis gas, known means such as a cooler for cooling and liquefying the pyrolysis gas, a purifier for increasing the purity of the monomer having a (meth)acrylic group contained in the pyrolysis gas, and a tank for storing the monomer having a (meth)acrylic group liquefied by cooling can be used in combination as needed without particular limitation. The gas treatment section preferably includes at least one selected from the group consisting of a cooling section that cools the pyrolysis gas and a purification section that purifies the pyrolysis gas.

[0053] (Raw material supply department) The recycling device of the present disclosure may further include a raw material supply section that supplies a (meth)acrylic polymer as a raw material to the pyrolysis section. The method for supplying the raw materials is not particularly limited and can be selected from known methods. The raw material supply unit may include a processing device for processing the raw material, such as crushing the raw material, a detector for detecting foreign matter contained in the raw material, a measuring device for controlling the amount of raw material fed in, and the like.

[0054] (Raw material drying section) The regeneration device of this embodiment may include a raw material drying section, which dries and removes water contained in the (meth)acrylic polymer supplied to the thermal decomposition section. Hereinafter, the treatment of removing water contained in the (meth)acrylic polymer by drying will also be referred to as "drying treatment of the (meth)acrylic polymer." In the present disclosure, the drying treatment of a (meth)acrylic polymer includes a treatment for partially removing water contained in the (meth)acrylic polymer and a treatment for completely removing water contained in the (meth)acrylic polymer.

[0055] The water content of the (meth)acrylic polymer before the drying treatment is not particularly limited. For example, when the water content of the (meth)acrylic polymer before the dehydration treatment is 5% by mass or more, 10% by mass or more, or 15% by mass or more, the effect of the drying treatment is greater. The drying treatment of the (meth)acrylic polymer is preferably carried out so that the water content of the (meth)acrylic polymer after the drying treatment is 1% by mass or less.

[0056] When drying the (meth)acrylic polymer, evaporation of water contained in the (meth)acrylic polymer may be promoted by adjusting one or more of the environmental conditions surrounding the (meth)acrylic polymer, such as temperature, relative humidity, airflow, and atmospheric pressure. From the viewpoint of easily controlling the moisture content of the (meth)acrylic polymer after drying, a method employing at least one of adjusting the temperature or airflow is preferred, and a method employing both adjusting the temperature and airflow may also be employed.

[0057] (Impurity gas treatment unit) The regeneration device of the present disclosure may include an impurity gas treatment section that treats the impurity gas generated in the thermal decomposition section. In the present disclosure, the term "impurity gas" refers to components other than the monomer having a (meth)acrylic group contained in the pyrolysis gas generated in the pyrolysis section. Examples of the impurity gas include chlorine gas and water vapor. The method for treating the impurity gas is not particularly limited and can be selected from known methods. As a means for treating impurity gases, known means such as adsorbents, absorbents, metal catalysts, filters, etc. can be used without any particular limitation, and can be combined as necessary. Specific examples of the adsorbent include alumina, calcium oxide, calcium carbonate, iron oxide, iron hydroxide, carbon, zeolite, a complex of iron oxide and / or metallic iron with carbon, a complex of calcium oxide and carbon, and a complex of iron oxide and / or metallic iron with calcium carbonate and / or calcium oxide and carbon. A specific example of the absorbent is an aqueous solution containing a reducing agent and a base. By contacting this aqueous solution with the pyrolysis gas, impurities in the pyrolysis gas can be absorbed. The base is preferably selected from the group consisting of sodium hydroxide, sodium carbonate, and sodium bicarbonate (NaHCO3). The reducing agent is preferably selected from the group consisting of sodium sulfite, hydrogen peroxide, sodium thiosulfate, and sodium bisulfite (or hydrogen sulfite) (NaHSO3). The adsorbent or absorbent used in the impurity gas treatment section may be one type or two or more types.

[0058] From the viewpoint of increasing the efficiency of removing impurity gases from pyrolysis gases, it is preferable that the adsorbent or absorbent has a large contact area with the pyrolysis gas, and from this viewpoint, the adsorbent or absorbent is preferably in particulate form.

[0059] (Residue storage area) The regeneration device of the present disclosure may further include a residue storage section that stores the residue discharged from the pyrolysis section. The method for storing the residue is not particularly limited and can be selected from known methods. The residue storage unit may include a processing device or the like that processes the residue into a disposable state. The method for storing the residue is not particularly limited and can be selected from known methods.

[0060] Second Embodiment A second embodiment of the present disclosure is a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a capturing step of capturing impurities contained in the pyrolysis gas; a gas treatment step for treating the pyrolysis gas after the impurities have been collected in the collection step, The collection step is a method for regenerating a (meth)acrylic polymer, in which impurities are collected by at least one collection mechanism selected from inertial impaction, interception, diffusion, and electrostatic action. The playback method of this embodiment may be implemented using the playback device of the first embodiment.

[0061] Details and preferred aspects of the pyrolysis step, the collection step and the gas treatment step are the same as the details and preferred aspects of the pyrolysis section, the collection section and the gas treatment section in the regeneration device of the first embodiment.

[0062] The regeneration method of this embodiment may further include a partial condensation step of condensing at least a portion of the impurities contained in the pyrolysis gas. When the regeneration method of the present embodiment includes a partial condensation step, the partial condensation step is preferably disposed between the thermal decomposition step and the collection step. Details and preferred aspects regarding the implementation of the partial condensation step are the same as the details and preferred aspects regarding the partial condensation section in the regeneration apparatus of the first embodiment.

[0063] The regeneration method of this embodiment may further include a second collection step of collecting impurities contained in the pyrolysis gas by gravity. Details and preferred aspects regarding the implementation of the second collection step are similar to the details and preferred aspects regarding the second collection section in the regeneration device of the first embodiment.

[0064] The regeneration method of the present embodiment may further include a raw material supplying step of supplying a (meth)acrylic polymer, a raw material drying step of drying the (meth)acrylic polymer, and / or an impurity gas treatment step of treating impurity gas generated in the thermal decomposition section. The details and preferred aspects of the raw material supplying step, raw material drying step, and impurity gas treating step are the same as the details and preferred aspects of the raw material supplying section, raw material drying section, and impurity gas treating section in the regeneration apparatus of the first embodiment.

[0065] According to the recycling method of the present embodiment, the (meth)acrylic polymer contained in the raw material is recycled into a monomer having a (meth)acrylic group by thermal decomposition. The reproduced monomer having a (meth)acrylic group is used, for example, as a raw material monomer for a (meth)acrylic polymer.

[0066] The monomer having a (meth)acrylic group obtained by the recycling method of this embodiment may contain methyl (meth)acrylate. The monomer having a (meth)acrylic group obtained by the recycling method of this embodiment may be a mixture of methyl (meth)acrylate and unavoidably contained monomers other than methyl (meth)acrylate (e.g., methyl isobutyrate, methyl propionate, methyl acrylate, etc.). In this case, the monomers other than methyl (meth)acrylate in the mixture may or may not be removed.

[0067] Third Embodiment A third embodiment of the present disclosure is a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a capturing step of capturing impurities contained in the pyrolysis gas; a gas treatment step for treating the pyrolysis gas after the impurities have been collected in the collection step, The collection step is a method for producing a monomer having a (meth)acrylic group, in which impurities are collected by at least one collection mechanism selected from inertial impaction, interception, diffusion, and electrostatic action. The manufacturing method of this embodiment may be carried out using the regenerating apparatus of the first embodiment.

[0068] Details and preferred aspects of the pyrolysis step, the collection step and the gas treatment step are the same as the details and preferred aspects of the pyrolysis section, the collection section and the gas treatment section in the regeneration device of the first embodiment.

[0069] The production method of this embodiment may further include a partial condensation step of condensing at least a portion of the impurities contained in the pyrolysis gas. When the production method of the present embodiment includes a partial condensation step, the partial condensation step is preferably disposed between the thermal decomposition step and the collection step. Details and preferred aspects regarding the implementation of the partial condensation step are the same as the details and preferred aspects regarding the partial condensation section in the regeneration apparatus of the first embodiment.

[0070] The manufacturing method of this embodiment may further include a second collection step of collecting impurities contained in the pyrolysis gas by gravity. Details and preferred aspects regarding the implementation of the second collection step are similar to the details and preferred aspects regarding the second collection section in the regeneration device of the first embodiment.

[0071] The production method of this embodiment may further include a raw material supplying step of supplying a (meth)acrylic polymer, a raw material drying step of drying the (meth)acrylic polymer, and / or an impurity gas treatment step of treating an impurity gas generated in the thermal decomposition section. The details and preferred aspects of the raw material supplying step, raw material drying step, and impurity gas treating step are the same as the details and preferred aspects of the raw material supplying section, raw material drying section, and impurity gas treating section in the regeneration apparatus of the first embodiment.

[0072] According to the production method of this embodiment, a monomer having a (meth)acrylic group is obtained as a thermal decomposition product of a (meth)acrylic polymer contained in the raw material. The monomer having a (meth)acrylic group obtained as a pyrolyzate is used, for example, as a raw material monomer for a (meth)acrylic polymer.

[0073] The monomer having a (meth)acrylic group obtained by the production method of this embodiment is used, for example, as a raw material monomer for a (meth)acrylic polymer.

[0074] The monomer having a (meth)acrylic group obtained by the production method of this embodiment may contain methyl (meth)acrylate. The monomer having a (meth)acrylic group obtained by the production method of this embodiment may be a mixture of methyl (meth)acrylate and a monomer other than methyl (meth)acrylate that may be inevitably contained (e.g., methyl isobutyrate, methyl propionate, methyl acrylate, etc.). In this case, the monomer other than methyl (meth)acrylate in the mixture may or may not be removed.

[0075] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the components shown in each drawing can be modified without departing from the scope of the present disclosure.

[0076] FIG. 1 is a diagram schematically illustrating an example of the configuration of a playback device according to the first embodiment. The regeneration device 10 shown in FIG. 1 includes a thermal decomposition section 11, a partial condensation section 12, a collection section 13, and a gas treatment section 14.

[0077] In the pyrolysis section 11, the (meth)acrylic polymer supplied to the regenerator 10 is pyrolyzed to obtain pyrolysis gas. In the partial condensation section 12, at least a part of the impurities contained in the pyrolysis gas obtained in the pyrolysis section 11 is condensed. In the collection section 13, impurities contained in the pyrolysis gas from which at least a portion of the impurities has been condensed in the partial condensation section 12 are collected. The gas processing section 14 processes the pyrolysis gas after the impurities have been collected in the collection section 13 .

[0078] 2A is a diagram schematically illustrating an example of the configuration of a collection unit included in the regeneration device of Embodiment 1. Arrows in the diagram indicate the flow direction of pyrolysis gas. 2A includes a tank 21 having an inlet 23 and an outlet 24 for pyrolysis gas, and a collector 22 disposed inside the tank 21. The inlet 23 and outlet 24 for pyrolysis gas are disposed so that the pyrolysis gas in the tank 21 passes through the collector 22 and the flow direction of the pyrolysis gas is the direction of gravity. Specifically, the inlet 23 for pyrolysis gas is disposed below the collector 22 in the direction of gravity, and the outlet 24 for pyrolysis gas is disposed above the collector 22.

[0079] The pyrolysis gas introduced into the tank 21 is in a state (mist state) where droplet-like impurities are contained in a gas containing a monomer having a (meth)acrylic group. The gaseous monomer having a (meth)acrylic group contained in the pyrolysis gas introduced into the tank 21 passes through a collector 22 and is discharged from an outlet 24 . Impurities 25 in the form of droplets contained in the pyrolysis gas introduced into the tank 21 are collected by the collector 22, and after the droplets grow in size, they fall and are stored in the tank 21. The impurities 25 stored in the tank 21 may be treated by a waste liquid treatment unit (not shown) connected to the tank 21.

[0080] 2B is a diagram schematically illustrating an example of the configuration of a collection unit included in the regeneration device of Embodiment 1. Collection unit 20 shown in Fig. 2B differs from collection unit 20 shown in Fig. 2A in that inlet 23 for pyrolysis gas is arranged above collection device 22 in the direction of gravity, and outlet 24 for pyrolysis gas is arranged below collection device 22.

[0081] Fig. 2C is a diagram schematically illustrating an example of the configuration of a collection unit included in the regeneration device of Embodiment 1. Collection unit 20 shown in Fig. 2C differs from collection unit 20 shown in Fig. 2A in that collection device 22, pyrolysis gas inlet 23, and pyrolysis gas outlet 24 are arranged so that the flow direction of the pyrolysis gas is horizontal. [Example]

[0082] Hereinafter, embodiments of the present disclosure will be described in detail based on examples, but the present disclosure is not limited to the following examples.

[0083] Example 1 Chemical recycling of a (meth)acrylic polymer was carried out, including the following steps (1) to (4): A colorless and transparent PMMA molded body was used as the (meth)acrylic polymer. The purity, content of high condensation point impurities, transparency, and coloration of the monomer (methyl methacrylate) obtained by chemical recycling were evaluated. The results are shown in Table 1.

[0084] (1) Pyrolysis process Using a twin-screw extruder (TEX-44, screw L / D: 60, manufactured by The Japan Steel Works, Ltd.), the (meth)acrylic polymer was pyrolyzed under the conditions of a screw rotation speed of 500 rpm, a cylinder temperature of 450°C, and a raw material supply rate of 50 kg / hour. (2) Decomposition process The temperature of the pyrolysis gas obtained from the twin-screw extruder (exit gas temperature) was adjusted to 100°C, and a mist-like pyrolysis gas containing droplets of impurities with condensation points higher than 100°C was obtained. (3) Collection process The impurities contained in the mist-like pyrolysis gas obtained in the partial condensation process were collected using a demister, which can capture 99% of droplets larger than 3 μm by inertial impaction. (4) Gas treatment process The pyrolysis gas from which the impurities had been collected in the collection step was cooled to obtain a liquid monomer.

[0085] <Comparative Example 1> Chemical recycling of the (meth)acrylic polymer was carried out in the same manner as in Example 1, except that step (3) was not carried out, and the resulting monomer was evaluated. The results are shown in Table 1.

[0086] <Comparative Example 2> Chemical recycling of a (meth)acrylic polymer was carried out in the same manner as in Example 1, except that steps (2) and (3) were not carried out, and the resulting monomer was evaluated. The results are shown in Table 1.

[0087] <Example 2> Chemical recycling of a (meth)acrylic polymer was carried out in the same manner as in Example 1, except that a colored PMMA molded body was used instead of a colorless and transparent PMMA molded body, and the resulting monomer was evaluated. The results are shown in Table 1.

[0088] <Comparative Example 3> Chemical recycling of the (meth)acrylic polymer was carried out in the same manner as in Example 2, except that step (3) was not carried out, and the resulting monomer was evaluated. The results are shown in Table 1.

[0089] <Comparative Example 4> Chemical recycling of the (meth)acrylic polymer was carried out in the same manner as in Example 2, except that steps (2) and (3) were not carried out, and the resulting monomer was evaluated. The results are shown in Table 1.

[0090] Example 3 Chemical recycling of a (meth)acrylic polymer was carried out in the same manner as in Example 1, except that the screw rotation speed of the twin-screw extruder in step (1) was changed to 500 rpm, the cylinder temperature to 430°C, and the raw material supply rate to 40 kg / h, and the resulting monomer was evaluated. The results are shown in Table 1.

[0091] [Table 1]

[0092] The purity and high condensation point impurity content of methyl methacrylate shown in Table 1 were measured using a gas chromatograph under the following conditions, using a monomer obtained by chemically recycling a (meth)acrylic polymer as a measurement sample.

[0093] (Measurement conditions) Equipment: GC-2010 Plus (manufactured by Shimadzu Corporation) Column: DB-1 (Agilent Technologies) Detector: FID 2010 Plus (Shimadzu Corporation) Column oven conditions Initial temperature: 40°C (hold time 1 minute) Heating rate: 8°C / min Intermediate temperature: 120℃ (hold time 0 minutes) Heating rate: 20°C / min Final temperature: 300°C (hold time 10 minutes) Sample vaporization conditions Vaporization chamber temperature: 300℃ Carrier gas: Helium Pressure: 50kPa Total flow rate: 220.1mL / min Column flow rate: 1.08 mL / min Linear speed: 31.1cm / sec Purge dose: 3.0mL / min Split ratio: 200 Detector conditions Detector temperature: 300℃ Sampling rate: 40msec Make-up gas: N2 Make-up flow rate: 30 mL / min H2 flow rate: 40mL / min Air flow rate: 400mL / min Autosampler conditions Injection volume: 1μL

[0094] The peak area (a1) corresponding to methyl methacrylate (retention time 4.13 minutes) and the total peak area (b1) detected when gas chromatography was performed under the above measurement conditions were measured. From these peak areas, the peak area ratio A (=a1 / b1) was calculated, and the purity of methyl methacrylate was calculated.

[0095] Furthermore, the sum of the peak areas from 4.13 minutes to 22 minutes (a2) was measured as the peak area corresponding to the high condensation point impurity. The peak area ratio B (= a2 / b1) was calculated from this peak area and b1, and the content of the high condensation point impurity was calculated.

[0096] The transparency shown in Table 1 was evaluated visually using a monomer obtained by chemically recycling a (meth)acrylic polymer as a measurement sample. Specifically, the light transmittance of the measurement sample placed in a 50 ml transparent glass sample bottle was evaluated according to the following criteria. A Transparent B Translucent C Opaque (opaque)

[0097] The coloring degree shown in Table 1 was evaluated visually using a monomer obtained by chemically recycling a (meth)acrylic polymer as a measurement sample. Specifically, the color observed when the measurement sample was placed in a 50 ml transparent glass sample bottle was evaluated.

[0098] As shown in Table 1, the monomers of the Examples obtained by carrying out the collection step in the chemical recycling of the (meth)acrylic polymer had higher MMA purity, lower contents of high condensation point impurities, and better visual evaluations of transparency and coloration than the monomers of the Comparative Examples obtained without carrying out the collection step in the chemical recycling of the (meth)acrylic polymer. [Explanation of symbols]

[0099] 10 Playback device 11 Pyrolysis section 12 Decomposition part 13 Collection section 14 Gas processing section 20 Collection section 21 Tank 22 Collection device 23 Pyrolysis gas inlet 24 Pyrolysis gas outlet 25 Impurities

Claims

1. a pyrolysis section for pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a collection unit that collects impurities contained in the pyrolysis gas; a gas treatment unit that treats the pyrolysis gas after impurities have been collected by the collection unit, The (meth)acrylic polymer regeneration device, wherein the collection section collects impurities by at least one collection mechanism selected from inertial impaction, interception, diffusion, and electrostatic action.

2. 2. The regenerating apparatus according to claim 1, wherein the pyrolysis gas supplied to the collection section is in a state in which droplets containing impurities are present in a gas containing a monomer having a (meth)acrylic group.

3. 3. The regenerating device according to claim 1, wherein the impurities collected by the collection unit include a component that condenses at a temperature higher than that of the monomer having a (meth)acrylic group.

4. 3. The regeneration device according to claim 1, further comprising a partial condensation section that condenses at least a portion of impurities contained in the pyrolysis gas.

5. The regeneration device according to claim 4 , wherein the partial condensation section is disposed between the thermal decomposition section and the collection section.

6. Further provided is a second collection section that collects impurities contained in the pyrolysis gas, 3. The regenerating device according to claim 1, wherein the second collection section collects impurities by gravity.

7. The regeneration device according to claim 1 or 2, further comprising a waste liquid treatment unit connected to the collection unit.

8. 3. The regeneration device according to claim 1, wherein the gas processing section includes at least one selected from the group consisting of a cooling section that cools the pyrolysis gas and a purification section that purifies the pyrolysis gas.

9. a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a capturing step of capturing impurities contained in the pyrolysis gas; a gas treatment step for treating the pyrolysis gas after the impurities have been collected in the collection step, The method for regenerating a (meth)acrylic polymer, wherein the capturing step captures impurities by at least one capturing mechanism selected from inertial impaction, interception, diffusion, and electrostatic action.

10. a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a capturing step of capturing impurities contained in the pyrolysis gas; a gas treatment step for treating the pyrolysis gas after the impurities have been collected in the collection step, A method for producing a monomer having a (meth)acrylic group, wherein the collection step collects impurities by at least one collection mechanism selected from inertial impaction, interception, diffusion, and electrostatic action.

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