WO2021230312A1 - Method for recycling waste polystyrene products - Google Patents

Method for recycling waste polystyrene products Download PDF

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Publication number
WO2021230312A1
WO2021230312A1 PCT/JP2021/018165 JP2021018165W WO2021230312A1 WO 2021230312 A1 WO2021230312 A1 WO 2021230312A1 JP 2021018165 W JP2021018165 W JP 2021018165W WO 2021230312 A1 WO2021230312 A1 WO 2021230312A1
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WIPO (PCT)
Prior art keywords
polystyrene
recycled
products
styrene monomer
waste polystyrene
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PCT/JP2021/018165
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French (fr)
Japanese (ja)
Inventor
衛 藤平
良 水口
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Dic株式会社
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Priority to KR1020227034841A priority Critical patent/KR20230013238A/en
Priority to CN202180033768.7A priority patent/CN115516016A/en
Priority to JP2022522191A priority patent/JP7318810B2/en
Publication of WO2021230312A1 publication Critical patent/WO2021230312A1/en

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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
    • B09B—DISPOSAL OF SOLID WASTE NOT OTHERWISE PROVIDED FOR
    • B09B3/00—Destroying solid waste or transforming solid waste into something useful or harmless
    • B09B3/50—Destroying solid waste or transforming solid waste into something useful or harmless involving radiation, e.g. electro-magnetic waves
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C15/00—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts
    • C07C15/40—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts substituted by unsaturated carbon radicals
    • C07C15/42—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts substituted by unsaturated carbon radicals monocyclic
    • C07C15/44—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts substituted by unsaturated carbon radicals monocyclic the hydrocarbon substituent containing a carbon-to-carbon double bond
    • C07C15/46—Styrene; Ring-alkylated styrenes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F12/00—Homopolymers and copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring
    • C08F12/02—Monomers containing only one unsaturated aliphatic radical
    • C08F12/04—Monomers containing only one unsaturated aliphatic radical containing one ring
    • C08F12/06—Hydrocarbons
    • C08F12/08—Styrene
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J11/00—Recovery or working-up of waste materials
    • C08J11/04—Recovery or working-up of waste materials of polymers
    • C08J11/10—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation
    • C08J11/12—Recovery or working-up of waste materials of polymers by chemically breaking down the molecular chains of polymers or breaking of crosslinks, e.g. devulcanisation by dry-heat treatment only
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2250/00—Layers arrangement
    • B32B2250/24—All layers being polymeric
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2272/00—Resin or rubber layer comprising scrap, waste or recycling material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
    • B32B2307/558—Impact strength, toughness
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2597/00—Tubular articles, e.g. hoses, pipes
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2325/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an aromatic carbocyclic ring; Derivatives of such polymers
    • C08J2325/02—Homopolymers or copolymers of hydrocarbons
    • C08J2325/04—Homopolymers or copolymers of styrene
    • C08J2325/06—Polystyrene
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/62—Plastics recycling; Rubber recycling
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
    • Y02W30/00—Technologies for solid waste management
    • Y02W30/50—Reuse, recycling or recovery technologies
    • Y02W30/82—Recycling of waste of electrical or electronic equipment [WEEE]

Definitions

  • the present invention relates to a method for recycling waste polystyrene products.
  • Material recycling is one of the recycling methods for waste polystyrene.
  • waste polystyrene is collected, washed, crushed, and pelletized, and then polystyrene products are manufactured again.
  • Patent Document 1 Various proposals have been made for material recycling of waste polystyrene (see, for example, Patent Document 1).
  • material recycling which manufactures polystyrene products by the remelting method, has a problem that the strength of polystyrene is lowered because the molecular weight of polystyrene is reduced by repeating melting of polystyrene.
  • naphtha-derived polystyrene formed by polymerizing naphtha-derived styrene monomer (hereinafter, also referred to as naphtha-derived polystyrene)
  • naphtha-derived polystyrene is compared with polystyrene produced by material recycling. It is necessary to add and reinforce.
  • waste polystyrene products so-called waste polystyrene products (hereinafter, also referred to as recycled polystyrene) becomes polystyrene having the same strength as polystyrene derived from naphtha.
  • waste polystyrene products hereinafter, also referred to as recycled polystyrene
  • An object of the present invention is to provide a method for recycling a waste polystyrene product, which can produce recycled polystyrene having higher strength than polystyrene produced by material recycling. Further, since material recycling of waste polystyrene products causes deterioration of the hue of polystyrene due to resin burning, it is an object of the present invention to provide a recycling method capable of suppressing deterioration of the hue of polystyrene.
  • the present invention includes the following aspects.
  • [1] A process of thermally decomposing a waste polystyrene product to obtain a recycled styrene monomer from the waste polystyrene.
  • a method of recycling waste polystyrene products characterized by containing.
  • [2] The method for recycling waste polystyrene products according to [1], wherein the waste polystyrene products include uncolored polystyrene products and colored polystyrene products.
  • [3] The method for recycling a waste polystyrene product according to [1] or [2], wherein the waste polystyrene product is crushed to obtain a crushed product of the waste polystyrene product, and the crushed product is thermally decomposed.
  • the step of obtaining the recycled styrene monomer is The process of pyrolyzing waste polystyrene products using a pyrolysis device, By supplying the steam generated by the thermal decomposition to the condenser, the gas flare component is removed from the thermal decomposition product in which the oil component containing the recycled styrene monomer and the gas flare component are mixed, and the oil component containing the recycled styrene monomer is removed.
  • the recycled styrene monomer contains at least one selected from the group consisting of an inorganic substance, an aromatic compound, a cyclohexadiene compound, and a cyclohexene compound, in addition to the styrene monomer, [1] to [6].
  • [8] Process of collecting waste polystyrene products The process of thermally decomposing the recovered waste polystyrene products to obtain recycled styrene monomer from the waste polystyrene, A step of polymerizing the recycled polystyrene monomer to obtain recycled polystyrene, and a step of obtaining a recycled polystyrene product made of the recycled polystyrene.
  • a method of recycling waste polystyrene products characterized by containing.
  • the present invention provides a method for recycling waste polystyrene products, which can produce recycled polystyrene in which deterioration of resin hue is suppressed. can do.
  • the method for recycling a waste polystyrene product of the present invention includes a step of thermally decomposing the waste polystyrene product to obtain a recycled styrene monomer from the waste polystyrene.
  • the recycling method of the present invention is a chemical recycling method for producing a styrene monomer, which is a raw material for polystyrene products, from waste polystyrene products.
  • Waste polystyrene is the waste of the recycled styrene monomer of the present invention, the polystyrene product made of petroleum-derived styrene monomer, or the polystyrene product obtained by material recycling.
  • a method for recycling waste polystyrene products including the following steps 1) to 4).
  • 1) Process of collecting waste polystyrene products (hereinafter, also referred to as recovery process) 2) A process of thermally decomposing the recovered waste polystyrene product to obtain recycled styrene monomer from the waste polystyrene (hereinafter, also referred to as a manufacturing process of recycled styrene monomer).
  • 3) A process of polymerizing recycled styrene monomer to obtain recycled polystyrene hereinafter, also referred to as a manufacturing process of recycled polystyrene).
  • the recycled styrene monomer means a recycled styrene monomer, that is, a styrene monomer obtained from waste polystyrene through a recycling step.
  • the recycled polystyrene refers to recycled polystyrene, that is, polystyrene obtained by polymerizing a recycled styrene monomer or polystyrene obtained by material recycling.
  • the recycled polystyrene products obtained in the step 4) above (hereinafter, also referred to as recycled polystyrene products) are supplied to the market. After that, the recycled polystyrene products that are no longer needed and the waste recycled polystyrene products such as the used recycled polystyrene products are collected again.
  • the recovered waste recycled polystyrene product is subjected to the thermal decomposition treatment in the step 2). As a result, the recycled styrene monomer can be produced again.
  • the recycled polystyrene products manufactured through the steps 1) to 4) are again subjected to the steps 1) to 4), and the recycled polystyrene products can be manufactured.
  • INDUSTRIAL APPLICABILITY According to the present invention, waste polystyrene products can be repeatedly manufactured into recycled polystyrene products, and a recycling system for waste polystyrene products can be established.
  • the waste polystyrene product 1 is recovered (recovery step A).
  • the recovered waste polystyrene product is subjected to various steps such as a thermal decomposition treatment step, an oil component acquisition step, and a distillation refining step to produce recycled monomer 2 (recycled styrene monomer manufacturing step B).
  • the manufactured recycled styrene monomer 2 is polymerized to produce recycled polystyrene 3 (recycled polystyrene manufacturing step C).
  • Various polystyrene products 4 are manufactured using the manufactured recycled polystyrene 3 (polystyrene product manufacturing process D).
  • waste polystyrene product 1 is the waste of the polystyrene product 4 obtained from the present invention, the polystyrene product containing petroleum-derived styrene monomer, or the polystyrene product obtained by material recycling.
  • FIG. 1 according to the recycling method of the present invention, it is possible to establish a recycling system for waste polystyrene products.
  • each of the above steps 1) to 4) will be described in detail.
  • waste polystyrene product refers to a discarded polystyrene product such as an unnecessary polystyrene product or a used polystyrene product.
  • the recovered waste polystyrene product is subjected to the thermal decomposition treatment in the step 2) above. 2) above
  • the waste polystyrene products used in the above step 2) do not need to be particularly sorted after recovery, and all the recovered waste polystyrene products can be subjected to the thermal decomposition treatment in the above step 2).
  • some polystyrene products are colored, but only uncolored polystyrene products can be used without any restrictions in material recycling.
  • Colored polystyrene products can only be recycled into products for specific purposes such as hangers.
  • colored polystyrene products for example, black polystyrene products
  • uncolored polystyrene products are not separated without separating colored polystyrene products (for example, black polystyrene products) from uncolored polystyrene products.
  • Uncolored recycled polystyrene products can be produced from waste polystyrene products, including polystyrene products.
  • both the uncolored polystyrene product and the colored (colored) polystyrene product can be subjected to the thermal decomposition treatment in the step 2) above in a mixed state.
  • the colored (colored) polystyrene product refers to a polystyrene product in which a colorant such as a pigment is combined in order to color the product in a colored manner. Examples of the combination include addition to a polystyrene base material, attachment of a colored laminated film, and the like. According to the present invention, it is not necessary to separate the products by color after collection, and not only uncolored polystyrene products but also colored polystyrene products can be recycled.
  • the present invention it is possible to reduce the labor involved in the sorting work after collection.
  • the recycling utilization rate of waste polystyrene products can be improved, and it can be expected that 100% of styrene of waste polystyrene products will be recycled.
  • a step of crushing the waste polystyrene product to obtain a crushed waste polystyrene product may be further provided, if necessary. That is, the waste polystyrene product may be crushed to obtain a crushed product of the waste polystyrene product, and the crushed product may be subjected to the thermal decomposition treatment in the step 2) above.
  • a condensable oil containing a styrene monomer (also referred to as a monomer oil component in the present invention) is obtained from a pyrolysis product produced by thermally decomposing polystyrene, and the condensable oil is purified. , Obtain recycled styrene monomer. The purity of styrene in the recycled styrene monomer differs depending on the purification method of the recycled styrene monomer.
  • the monomer oil component means an oil component containing a styrene monomer.
  • a preferred embodiment of the recycled styrene monomer production step B is as follows. Pyrolysis waste polystyrene products. As a result, a pyrolysis product in which the monomer oil component and the gas flare component are mixed is generated as steam. By condensing and separating the vapor, the gas flare component is removed and the monomer oil component is obtained. A styrene monomer is obtained by distilling and refining the monomer oil component. In this way, styrene monomer can be produced from waste polystyrene. That is, a preferred embodiment of the recycled styrene monomer manufacturing step B includes a manufacturing step including a thermal decomposition treatment step, an oil component acquisition step, and a distillation refining step. Further, in the present invention, it is more preferable that the manufacturing step includes a separation step after the thermal decomposition treatment step.
  • each step constituting the recycled styrene monomer manufacturing step B will be described in detail with reference to FIG. 2.
  • Thermal decomposition process The recovered waste polystyrene product 1 is thermally decomposed. As shown in FIG. 2, when the waste polystyrene product 1 is thermally decomposed by using the thermal decomposition apparatus a, steam (decomposition gas) 10 is generated.
  • This pyrolysis product obtained as steam contains a monomer oil component 14 and a gas flare component 15.
  • the gas flare component means a gas component or a coke component.
  • the type of the thermal decomposition apparatus is not particularly limited as long as a thermal decomposition product containing the monomer oil component 14 and the gas flare component 15 can be obtained from polystyrene as described above, but for example, thermal decomposition using a microwave is used. It is preferably a device.
  • microwave means an electromagnetic wave having a wavelength of 1 meter to 1 millimeter, or an electromagnetic wave having a frequency of 300 MHz (0.3 GHz) to 300 GHz.
  • the microwave suitable for use in the present invention is from about 915 MHz to about 2450 MH. It is an electromagnetic wave with a frequency of z.
  • the microwave source include a magnetron tube.
  • a catalyst to the waste polystyrene product to be subjected to the thermal decomposition treatment in order to initiate microwave thermal decomposition of the waste polystyrene product.
  • the catalyst is not particularly limited as long as it absorbs microwaves, transfers heat to the waste polystyrene product, and contributes to the thermal decomposition reaction of the waste polystyrene product, and can be appropriately selected depending on the intended purpose, for example.
  • a catalyst containing a compound having a high dielectric loss at microwave frequencies is preferable to add to the waste polystyrene product to be subjected to the thermal decomposition treatment in order to initiate microwave thermal decomposition of the waste polystyrene product.
  • the catalyst is not particularly limited as long as it absorbs microwaves, transfers heat to the waste polystyrene product, and contributes to the thermal decomposition reaction of the waste polystyrene product, and can be appropriately selected depending on the intended purpose, for example.
  • the catalyst may be a catalyst consisting of carbonaceous residues from a previous pyrolysis reaction, ceramic beads containing a microwave absorbing additive, pellets containing a microwave absorbing additive, or a combination thereof. May be good.
  • a microwave absorption additive For example, silicon carbide, boron nitride and the like can be mentioned.
  • the catalyst may be a catalyst composed of a carbon compound containing about 80% by mass to about 90% by mass of carbon, and examples thereof include graphite.
  • the catalyst is preferably contained in an amount of 0.5% by mass to 50% by mass, preferably 0.5% by mass to 5% by mass, in a raw material to be subjected to a thermal decomposition treatment in which the catalyst and the waste polystyrene product are combined. It is more preferable that it is contained in an amount of 0.5% by mass to 2.5% by mass.
  • the thermal decomposition treatment is preferably performed in a situation where oxygen is not added.
  • no oxygen is added means that no molecular oxygen (O 2 ) gas is added.
  • no molecular oxygen (O 2 ) gas is added, and the pyrolysis treatment is performed when the oxygen content in the pyrolysis apparatus is a residual amount suitable for proceeding with the pyrolysis. Is preferably started.
  • the desired content of oxygen remaining in the thermal decomposition apparatus is preferably about 10% by volume or less, and more preferably about 5% by volume or less.
  • the pyrolysis device may be provided with anaerobic means for purging the pyrolysis device.
  • the anaerobic means include the above-mentioned inert gas, fluid and the like.
  • the fluid may be water.
  • the inert gas include argon, nitrogen, steam and the like.
  • a vacuum source such as a vacuum pump or a Venturi tube can be mentioned.
  • the anaerobic means may be the above-mentioned inert gas, fluid, vacuum source, or a combination thereof.
  • the steam generated by the initial evaporation of water present in the product purges the atmosphere in the pyrolysis apparatus and enables anoxic pyrolysis. Therefore, in the present invention, it is preferable that the pyrolysis treatment is performed under steam purging. Alternatively, a predetermined amount of water may be added to the waste polystyrene product to ensure proper purging of air by evaporation of water. Molecular oxygen (O 2 ) gas is not added into the pyrolyzer, but the waste may contain large amounts of oxygen. In the present invention, the water is allowed to evaporate before the start of the thermal decomposition reaction.
  • the steam generated in the pyrolysis apparatus discharges the air present therein, so that the pyrolysis reaction may occur in a steam environment instead of air.
  • the pyrolyzer is sealed. In the present invention, it may be carried out by steam pyrolysis without introduction of additional oxygen, instead of the completely oxygen-free pyrolysis performed in a nitrogen or argon atmosphere, which is usually performed as an anaerobic means.
  • the product is heated and the polystyrene is decomposed.
  • the thermal decomposition treatment temperature of the waste polystyrene is preferably about 300 ° C. to about 650 ° C. More preferably, it is from about 300 ° C to about 450 ° C.
  • the thermal decomposition apparatus a when the waste polystyrene product is thermally decomposed by using the thermal decomposition apparatus a using microwaves, the above-mentioned steam (mixture of monomer oil component and gas flare component) 10 is generated.
  • the slurry component remains in the apparatus.
  • the steam 10 is separated into a monomer oil component 14 and a gas flare component 15 by being condensed and separated using a condenser c.
  • the thermal decomposition treatment by the thermal decomposition apparatus may be performed a plurality of times as shown in FIG.
  • the steam 10 may be obtained by providing the thermal decomposition treatment step a plurality of times (which is performed twice in FIG. 3).
  • thermal decomposition By performing thermal decomposition using microwaves, it is possible to efficiently apply heat uniformly from the inside to polystyrene in the thermal decomposition equipment, compared to a thermal decomposition furnace using a normal external heater.
  • the thermal decomposition rate is high, and the purity of the styrene monomer in the monomer oil component can be increased.
  • ⁇ Separation process it is preferable to perform a separation step on the slurry component 11 generated by the thermal decomposition treatment step. That is, for the slurry component generated by thermal decomposition, a light liquid such as styrene monomer, styrene oligomer, ethylbenzene, and benzene is separated from the slurry component by using a separation device, and a solid substance is separated from the charcoal or an inorganic substance. It is preferable that the clarified slurry from which the solid matter has been removed is thermally decomposed again using a thermal decomposition apparatus. For example, as shown in FIG.
  • the slurry component 11 generated in the apparatus is treated by using the separating apparatus b.
  • the clarified slurry 12 and the solid substance (char / inorganic substance) 13 are separated by the separating device b, and then the clarified slurry 12 is recharged into the heat separating device a.
  • the char refers to a carbonaceous by-product generated by thermal decomposition.
  • the step of obtaining the clarified slurry 12 from the slurry component 11 and charging the clarified slurry 12 into the thermal separation device a can be repeated.
  • the separating device b can remove impurities contained in the waste polystyrene product that are unnecessary for recycling.
  • impurities examples include pigments for coloring polystyrene products used in waste polystyrene products, molding components for producing products, and the like.
  • a separation step for removing these impurities for example, even if a colored polystyrene product is targeted for recycling, a recycled styrene monomer having a good hue and quality can be produced.
  • the separation step is effective in the recycling method of the present invention in which not only uncolored polystyrene products but also colored polystyrene products are to be recycled.
  • a recycled styrene monomer of good quality can be produced in high yield. Further, the accumulation of the solid matter 13 in the pyrolysis apparatus can be suppressed, the number of cleanings of the pyrolysis furnace can be reduced, and the monomer oil can be continuously produced.
  • Oil component acquisition process The pyrolysis product produced by thermally decomposing the waste polystyrene is condensed and separated by utilizing the difference in boiling point, and separated into the monomer oil component 14 and the gas flare component 15. Then, the monomer oil component 14 is subjected to the distillation refining step of the next step.
  • the steam 10 generated by the thermal decomposition treatment is supplied to the condenser c.
  • the condenser c is provided with a cooling pipe through which cooling water flows, and cools the steam (decomposition gas) discharged from the thermal decomposition apparatus a to condense and separate high boiling point components.
  • the separated monomer oil component 14 which is a high boiling point component is supplied to the first distillation column d, and the gas flare component 15 which is a low boiling point component that does not condense is discharged to the outside of the container of the condenser.
  • the monomer oil component 14 excluding the gas flare component 15 may be subjected to a step of being subjected to a thermal decomposition apparatus again before being subjected to a distillation refining step.
  • a monomer obtained by separating a dimer component from the monomer oil component 14 using a condenser and subjecting the dimer component to a thermal decomposition treatment using a thermal decomposition apparatus By adding the oil component to the remaining monomer oil component obtained by removing the dimer component from the previously obtained monomer oil component 14, the total monomer oil component can be provided to the first distillation column d. This makes it possible to increase the yield of the recycled styrene monomer.
  • the dimer component may contain an oligomer such as a trimer in addition to the dimer.
  • the monomer oil component 14 is separated into a styrene monomer and other components by performing distillation purification using a distillation column. For example, as shown in FIG. 2, two distillation columns are used. Then, in the first distillation column d, mainly benzene / toluene / ethylbenzene component 16 is separated from the monomer oil 14, and the remaining components are provided to the second distillation column e. Next, in the second distillation column e, the dimer component / other component 17 ( ⁇ -methylstyrene or the like) is separated to obtain a styrene monomer (so-called recycled styrene monomer 2).
  • the dimer component may contain an oligomer such as a trimer in addition to the dimer.
  • the recycled styrene monomer according to the present invention thus obtained is a styrene monomer having good quality. Therefore, the recycled polystyrene produced by using the recycled styrene monomer obtained in the present invention is a good recycled polystyrene showing the same strength and hue as the polystyrene derived from naphtha.
  • a step of subjecting the dimer component / other ( ⁇ -methylstyrene or the like) component 17 separated from the styrene monomer to the thermal decomposition apparatus again may be included. I do not care.
  • the dimer component / other ( ⁇ -methylstyrene or the like) component 17 is separated from the second distillation column e.
  • the separated dimer component / other component 17 ( ⁇ -methylstyrene or the like) is subjected to the thermal decomposition apparatus a again.
  • the dimer component / other component ( ⁇ -methylstyrene, etc.) 17 By performing the thermal decomposition treatment again, an additional recycled styrene monomer can be obtained.
  • the yield of the recycled styrene monomer can be further increased by summing up the additionally obtained recycled styrene monomer and the already obtained recycled styrene monomer 2 shown in FIG.
  • the recycled styrene monomer manufacturing step B which manufactures the recycled styrene monomer through the thermal decomposition treatment step, the oil component acquisition step, and the distillation refining step, is a manufacturing method in which CO 2 emissions are suppressed. Therefore, it can be said that the polystyrene product recycling method of the present invention is a manufacturing method having a high life cycle assessment (LCA) evaluation.
  • LCA life cycle assessment
  • the recycled styrene monomer obtained in the present invention is of good quality, but contains a small amount of impurities within a range that does not adversely affect practical use.
  • Impurities include toluene, benzene, cumene, dimer, trimer, ethylbenzene, ⁇ -Aromatic compounds such as methylstyrene, n-propylbenzene and phenylacetylene may not be completely removed and may be slightly contained in the recycled styrene monomer.
  • Inorganic substances such as silicon, copper, iron, titanium, and carbon may be contained as impurities.
  • 1,3-cyclohexadiene, 2-ethyl-1,3-cyclohexadiene, 2-vinyl-1,3-cyclohexadiene, 2-methyl-1,3-cyclohexadiene, 1,4-cyclo Hexadiene, 2-ethyl-1,4-cyclohexadiene, 2 -It may contain a small amount of compounds such as cyclohexadiene compounds such as vinyl-1,4-cyclohexadiene and 2-methyl-1,4-cyclohexadiene, and cyclohexene compounds such as cyclohexene and cyclohexenehexane. ..
  • the upper limit of the content of the above impurities in the recycled styrene monomer is usually 10. It may be 5% by mass or less, may be 3% by mass or less, may be 1% by mass or less, and the lower limit is not particularly limited, but is usually more than 0% by mass. These upper and lower limits may be any combination.
  • the content of impurities in the recycled styrene monomer is usually 0. It may be more than 0% by mass and 10% by mass or less, more than 0% by mass and 5% by mass or less, more than 0% by mass and 3% by mass or less, and more than 0% by mass and 1% by mass or less.
  • the upper limit of the content of the inorganic component in the recycled styrene monomer is usually 0.1% by mass or less, may be 0.01% by mass or less, may be 0.001% by mass or less, and the lower limit is particularly limited. Not done, but usually more than 0% by weight. These upper and lower limits may be any combination.
  • the content of inorganic components in recycled styrene monomers is usually 0. It may be more than 0.1% by mass and less than 0.1% by mass, more than 0% by mass and less than 0.01% by mass, more than 0% by mass and less than 0.001% by mass, and more than 0% by mass and less than 1% by mass. ..
  • the obtained recycled polystyrene monomer is polymerized to obtain recycled polystyrene.
  • the obtained recycled polystyrene is a recycled polystyrene having improved strength as compared with the polystyrene produced by material recycling.
  • the obtained recycled polystyrene is polystyrene in which deterioration of hue due to resin burning is suppressed.
  • the styrene monomer polymerization method include a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and a gas phase polymerization method, and any of these methods can be adopted.
  • the solution polymerization method is a method of mixing 5 to 20% of a solvent such as ethylbenzene or toluene having a boiling point of 130 ° C. to 200 ° C. with a styrene monomer and polymerizing the styrene monomer. It is a method of adding and heating to polymerize, and the suspension polymerization method is, for example, a method of dispersing a styrene monomer as particles in a large amount of water using a dispersant and polymerizing using a catalyst such as peroxide. ..
  • the embodiment of the recycled polystyrene obtained by polymerizing the recycled styrene monomer may include not only a polymer of styrene alone (styrene homopolymer) but also a copolymer of a styrene monomer and a monomer other than styrene (copolymer). It may also include rubber-modified polystyrene graft-polymerized in the presence of butadiene rubber or the like.
  • the obtained recycled polystyrene shows excellent strength when the strength is evaluated by the following measuring method.
  • the strength of polystyrene derived from naphtha is 100
  • the strength of polystyrene obtained by material recycling is about 90.
  • the lower limit of the strength of recycled polystyrene in the present invention is usually 90. It is higher than, preferably 95 or more, more preferably 97 or more, still more preferably 99 or more, and the upper limit is not particularly limited, but is usually 100 or less. These upper and lower limits may be any combination.
  • the strength of polystyrene derived from naphtha is 100
  • the strength of recycled polystyrene may be 100 or more.
  • Strength of polystyrene derived from naphtha is 1 When it is set to 00, the strength of the recycled polystyrene obtained by the present invention is usually larger than 90 and 100 or less, preferably 95 or more and 100 or less, more preferably 97 or more and 100 or less, and further preferably 99 or more and 100 or less.
  • the strength of polystyrene can be evaluated by, for example, tensile fracture stress according to JIS K 7161-1, or by bending strength according to JIS K 7171. Further, in the case of rubber-modified polystyrene, it can be evaluated by Charpy impact strength according to JIS K 711-1.
  • the obtained recycled polystyrene shows a good hue in which the yellowness is suppressed when the hue is evaluated by the following measuring method. Specifically, the hue is evaluated by the degree of yellowness (YI value) or the like. As for the YI value, the larger the positive side, the stronger the yellow color, and the larger the negative side, the stronger the blue color.
  • the YI value of the recycled polystyrene obtained in the present invention is lower than the YI value of the polystyrene obtained by material recycling, and the difference between the YI values is usually 0.1 or more, preferably 0.3 or more, more preferably 0.5 or more. More preferably, it is 1.0 or more. Y There is no particular upper limit to the difference in I values.
  • the hue of polystyrene can be measured, for example, according to JIS K 7373.
  • polystyrene products if recycled polystyrene is used, There are no particular restrictions, and it can be appropriately selected according to the purpose. For example, by producing a composition containing polystyrene and other components such as colorants, water, and organic solvents as needed, polystyrene products used as, for example, coating agents, inks, and adhesives can be produced. can do.
  • polystyrene products such as stretched sheets and foamed sheets can be manufactured by molding a composition containing recycled polystyrene into a sheet shape. Further, by molding a polystyrene sheet, a polystyrene product such as a food packaging container (for example, a food tray) can be manufactured.
  • polystyrene products for food containers such as cups and bottles can be manufactured by injection molding or injection blow molding of a composition containing recycled polystyrene.
  • material-recycled plastics are limited in their use because they cannot be brought into direct contact with food due to concerns about migration of the contents when used in food packaging containers.
  • the recycled plastic obtained by the present invention is obtained by decomposing waste polyplastic into a monomer, purifying it, and polymerizing it, it can come into direct contact with food and has no limitation on its use.
  • waste polystyrene can include these copolymers.
  • Example 1 Used polystyrene products were collected, then ground and pelletized. 1 ton of pelletized waste polystyrene was put into a thermal decomposition apparatus using microwaves. The reaction temperature in the pyrolysis device was set to 350 ° C, and 2% by mass with respect to waste polystyrene was used as a catalyst. The silicon carbide was subjected to a thermal decomposition treatment under steam purging. As a result, 600 kg of crude recycled styrene monomer was obtained (yield 60%). The purity of the recycled styrene monomer a after purification was less than 95%.
  • Example 2 In Example 1, crude recycled styrene was obtained in the same manner as in Example 1 except that the monomer oil component excluding the gas flare component was subjected to a step of being subjected to a thermal decomposition apparatus again before being subjected to a distillation refining step. Obtained a monomer. As a result, 840 kg of crude recycled styrene monomer was obtained (yield 84%). The purity of the recycled styrene monomer b after purification was a little over 99.8%.
  • Example 3 In Example 1, except that the step of subjecting the dimer component / other ( ⁇ -methylstyrene or the like) separated from the crude recycled styrene monomer to the thermal decomposition apparatus again in the second distillation column was added. , Recycled styrene monomer c was obtained in the same manner as in Example 1. As a result, another 240 kg of crude recycled styrene monomer was obtained from the dimer component / other ( ⁇ -methylstyrene or the like) component separated in Example 1. When combined with the recycled styrene monomer a obtained in Example 1, a total of 840 from Example 1 and Example 3 kg of crude recycled styrene monomer was obtained (yield 84%). The purity of the recycled styrene monomer c after purification was less than 95%.
  • Example 4 Using the recycled styrene monomers a to c obtained in Examples 1 to 3, respectively, a mixed solution consisting of 95 parts of styrene and 5 parts of toluene was prepared, and further, as an organic peroxide, 400 ppm of t-butylper with respect to styrene was prepared. Oxybenzoate was added and supplied to a connected tubular reactor at 120-160 ° C. for continuous bulk polymerization. The mixed solution obtained by polymerization was heated to 220 ° C. with a heat exchanger to remove volatile components under a reduced pressure of 50 mmHg, and then pelletized to obtain recycled polystyrenes A to C. The strength and hue of each of the obtained recycled polystyrenes A to C were evaluated by the methods described below.
  • Comparative Example 1 100 parts by mass of the used styrene resin composition was melt-kneaded at a cylinder temperature of 220 ° C. using a twin-screw kneading extruder, and the strands were water-cooled and then pelletized to obtain polystyrene D.
  • polystyrene D obtained by material recycling, by the method described below. Intensity and hue were evaluated.
  • the recycled polystyrenes A to C exhibited superior strength and hue as compared with the polystyrene D obtained by material recycling.
  • the measured values of the strength of polystyrene D obtained by material recycling were 45 MPa, whereas the measured values of the strength of the recycled polystyrenes A to C were all 50 MPa.
  • the YI value of polystyrene D obtained by material recycling was 1.0, whereas that of recycled polystyrenes A to C was 0.4.
  • the recycled styrene monomer when the recycled styrene monomer is produced from waste polystyrene by using the recycling method of the present invention, the recycled styrene monomer can be produced with high yield and high purity. According to the recycling method of the present invention, it was found that high-quality styrene monomer could be produced from waste polystyrene, and the recycled polystyrene obtained by polymerizing the recycled styrene monomer was excellent in strength and hue. INDUSTRIAL APPLICABILITY According to the present invention, a 100% recycled polystyrene recycling system can be established, which can be expected to recycle 100% of styrene of waste polystyrene products.

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Abstract

The present invention addresses the problem of providing a method for recycling waste polystyrene products that makes it possible to produce recycled polystyrene exhibiting the same strength as naphtha-derived polystyrene. The problem is solved by a method for recycling waste polystyrene products that includes a step for performing a pyrolysis treatment on waste polystyrene products to obtain recycled styrene monomers from the waste polystyrene. Preferably, the problem is solved by the method for recycling waste polystyrene products, wherein the waste polystyrene products include colorless polystyrene products and colored polystyrene products.

Description

廃ポリスチレン製品のリサイクル方法How to recycle waste polystyrene products
　本発明は、廃ポリスチレン製品のリサイクル方法に関する。 The present invention relates to a method for recycling waste polystyrene products.
　工場や家庭から排出されるプラスチック類には種々のプラスチックが存在するが、中で
もポリスチレンは、食品包装用トレイ、電化製品や情報機器のケース、断熱材、緩衝材な
ど多くの分野に利用されており、廃プラスチックに占める割合も多い。そのため大量に排
出される廃ポリスチレンを資源としてリサイクルすることは重要な技術的課題であり、そ
のため種々のリサイクル方法が提案されている。 There are various types of plastics discharged from factories and households, but polystyrene is used in many fields such as food packaging trays, cases for electrical appliances and information equipment, heat insulating materials, and cushioning materials. , It also accounts for a large proportion of waste plastic. Therefore, recycling waste polystyrene discharged in large quantities as a resource is an important technical issue, and various recycling methods have been proposed.
　廃ポリスチレンのリサイクル方法としてマテリアルリサイクルがある。マテリアルリサ
イクルでは、廃ポリスチレンを回収し、洗浄／粉砕／ペレット化の各工程を経て、再びポ
リスチレン製品を製造する。廃ポリスチレンのマテリアルリサイクルについて各種提案が
なされている（例えば、特許文献１参照）。 Material recycling is one of the recycling methods for waste polystyrene. In material recycling, waste polystyrene is collected, washed, crushed, and pelletized, and then polystyrene products are manufactured again. Various proposals have been made for material recycling of waste polystyrene (see, for example, Patent Document 1).
特開２０２０－７４２４号公報Japanese Unexamined Patent Publication No. 2020-7424
　しかし、再溶融法によりポリスチレン製品を製造するマテリアルリサイクルは、ポリス
チレンの溶融を繰り返すことでポリスチレンが低分子化するため、ポリスチレンの強度が
下がるという問題がある。ナフサ由来のスチレンモノマーを重合して形成されるポリスチ
レン（以下、ナフサ由来のポリスチレンともいう）と同等の強度を得るためには、例えば
、マテリアルリサイクルで製造されるポリスチレンに対して、ナフサ由来のポリスチレン
を加えて補強する必要がある。 However, material recycling, which manufactures polystyrene products by the remelting method, has a problem that the strength of polystyrene is lowered because the molecular weight of polystyrene is reduced by repeating melting of polystyrene. In order to obtain the same strength as polystyrene formed by polymerizing naphtha-derived styrene monomer (hereinafter, also referred to as naphtha-derived polystyrene), for example, naphtha-derived polystyrene is compared with polystyrene produced by material recycling. It is necessary to add and reinforce.
　そこで、使用済みのポリスチレン製品、いわゆる廃ポリスチレン製品をリサイクルして
得られるポリスチレン（以下、リサイクルポリスチレンともいう）が、ナフサ由来のポリ
スチレンと同等の強度を示すポリスチレンとなるようなリサイクルポリスチレンを製造で
きる、廃ポリスチレン製品の新しいリサイクル方法が望まれている。 Therefore, it is possible to produce recycled polystyrene in which the polystyrene obtained by recycling used polystyrene products, so-called waste polystyrene products (hereinafter, also referred to as recycled polystyrene) becomes polystyrene having the same strength as polystyrene derived from naphtha. A new recycling method for waste polystyrene products is desired.
　本発明は、マテリアルリサイクルで製造されるポリスチレンと比べて強度が向上したリ
サイクルポリスチレンを製造できる、廃ポリスチレン製品のリサイクル方法を提供するこ
とを目的とする。また、廃ポリスチレン製品をマテリアルリサイクルすることで樹脂焼け
によるポリスチレンの色相悪化が生じるため、ポリスチレンの色相悪化を抑制できるリサ
イクル方法を提供することを目的とする。 An object of the present invention is to provide a method for recycling a waste polystyrene product, which can produce recycled polystyrene having higher strength than polystyrene produced by material recycling. Further, since material recycling of waste polystyrene products causes deterioration of the hue of polystyrene due to resin burning, it is an object of the present invention to provide a recycling method capable of suppressing deterioration of the hue of polystyrene.
　本発明者は、上記課題を解決するために鋭意研究を重ねた結果、回収した廃ポリスチレ
ンから熱分解することにより、スチレンモノマーを再生するケミカルリサイクルを利用す
ることにより、上記課題を解決できることを見出し、本発明を完成するに至った。 As a result of intensive research to solve the above problems, the present inventor has found that the above problems can be solved by utilizing chemical recycling that regenerates styrene monomer by thermally decomposing the recovered waste polystyrene. , The present invention has been completed.
　すなわち、本発明は、以下の態様を包含するものである。
[１]廃ポリスチレン製品を熱分解処理して、廃ポリスチレンからリサイクルスチレンモノ
マーを得る工程、
　を含むことを特徴とする廃ポリスチレン製品のリサイクル方法。
[２]前記廃ポリスチレン製品が、無着色のポリスチレン製品と有色のポリスチレン製品と
を含む、[１]に記載の廃ポリスチレン製品のリサイクル方法。
[３]前記廃ポリスチレン製品を粉砕し、廃ポリスチレン製品の粉砕物を得て、前記粉砕物
を熱分解処理する、[１]又は[２]に記載の廃ポリスチレン製品のリサイクル方法。
[４]前記リサイクルスチレンモノマーを得る工程が、
　熱分解装置を用いて、廃ポリスチレン製品を熱分解する工程、
　前記熱分解により発生した蒸気を凝縮器に供することにより、リサイクルスチレンモノ
マーを含む油成分とガスフレア成分とが混合された熱分解生成物から、ガスフレア成分を
除去し、リサイクルスチレンモノマーを含む油成分を得る工程、及び
　前記リサイクルスチレンモノマーを含む油成分に対し、蒸留塔を用いて、リサイクルス
チレンモノマーを純度を向上させるために蒸留精製する工程、
　を含む、[１]から[３]のいずれかに記載の廃ポリスチレン製品のリサイクル方法。
[５]前記熱分解により生じたスラリー成分に対し、分離装置を用いて、前記スラリー成分
から固形物を除去する工程、及び
　前記固形物が除去された清澄スラリーに対し、前記熱分解装置を用いて、熱分解する工
程、
　をさらに含む、[４]に記載の廃ポリスチレン製品のリサイクル方法。
[６]前記熱分解装置が、マイクロ波を用いた熱分解装置である、[４]又は[５]に記載の廃
ポリスチレン製品のリサイクル方法。
[７]前記リサイクルスチレンモノマーは、スチレンモノマー以外に、無機物、芳香族化合
物、シクロヘキサジエン系化合物、及びシクロヘキセン系化合物からなる群から選択され
る少なくとも１種を含有する、[１]から[６]のいずれかに記載の廃ポリスチレン製品のリ
サイクル方法。
[８]廃ポリスチレン製品を回収する工程、
　回収された廃ポリスチレン製品を熱分解処理し、廃ポリスチレンからリサイクルスチレ
ンモノマーを得る工程、
　前記リサイクルスチレンモノマーを重合し、リサイクルポリスチレンを得る工程、及び
　前記リサイクルポリスチレンからなるリサイクルされたポリスチレン製品を得る工程、
　を含むことを特徴とする廃ポリスチレン製品のリサイクル方法。 That is, the present invention includes the following aspects.
[1] A process of thermally decomposing a waste polystyrene product to obtain a recycled styrene monomer from the waste polystyrene.
A method of recycling waste polystyrene products, characterized by containing.
[2] The method for recycling waste polystyrene products according to [1], wherein the waste polystyrene products include uncolored polystyrene products and colored polystyrene products.
[3] The method for recycling a waste polystyrene product according to [1] or [2], wherein the waste polystyrene product is crushed to obtain a crushed product of the waste polystyrene product, and the crushed product is thermally decomposed.
[4] The step of obtaining the recycled styrene monomer is
The process of pyrolyzing waste polystyrene products using a pyrolysis device,
By supplying the steam generated by the thermal decomposition to the condenser, the gas flare component is removed from the thermal decomposition product in which the oil component containing the recycled styrene monomer and the gas flare component are mixed, and the oil component containing the recycled styrene monomer is removed. The step of obtaining and the step of distilling and purifying the recycled styrene monomer in order to improve the purity of the oil component containing the recycled styrene monomer by using a distillation tower.
The method for recycling a waste polystyrene product according to any one of [1] to [3], which comprises.
[5] A step of removing a solid substance from the slurry component using a separating device for the slurry component generated by the thermal decomposition, and using the thermal decomposition device for the clarified slurry from which the solid substance has been removed. And the process of thermal decomposition,
The method for recycling waste polystyrene products according to [4], further comprising.
[6] The method for recycling a waste polystyrene product according to [4] or [5], wherein the pyrolysis device is a pyrolysis device using microwaves.
[7] The recycled styrene monomer contains at least one selected from the group consisting of an inorganic substance, an aromatic compound, a cyclohexadiene compound, and a cyclohexene compound, in addition to the styrene monomer, [1] to [6]. The method for recycling waste polystyrene products described in any of the above.
[8] Process of collecting waste polystyrene products,
The process of thermally decomposing the recovered waste polystyrene products to obtain recycled styrene monomer from the waste polystyrene,
A step of polymerizing the recycled polystyrene monomer to obtain recycled polystyrene, and a step of obtaining a recycled polystyrene product made of the recycled polystyrene.
A method of recycling waste polystyrene products, characterized by containing.
　本発明により、マテリアルリサイクルで製造されるポリスチレンと比べて強度が向上し
たリサイクルポリスチレンが製造できる、廃ポリスチレン製品のリサイクル方法を提供す
ることができる。
　また、廃ポリスチレン製品をマテリアルリサイクルすることで生じる樹脂焼けが本発明
では起きないことから、本発明により、樹脂の色相の悪化が抑制されたリサイクルポリス
チレンを製造できる、廃ポリスチレン製品のリサイクル方法を提供することができる。 INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for recycling a waste polystyrene product, which can produce recycled polystyrene having higher strength than polystyrene produced by material recycling.
Further, since resin burning caused by material recycling of waste polystyrene products does not occur in the present invention, the present invention provides a method for recycling waste polystyrene products, which can produce recycled polystyrene in which deterioration of resin hue is suppressed. can do.
本発明の廃ポリスチレン製品のリサイクル方法の一態様を示す概略図である。It is a schematic diagram which shows one aspect of the recycling method of the waste polystyrene product of this invention. 本発明の廃ポリスチレン製品のリサイクル方法におけるリサイクルスチレンモノマーの製造工程の一態様を示す概略図である。It is a schematic diagram which shows one aspect of the manufacturing process of the recycled styrene monomer in the method of recycling a waste polystyrene product of this invention. 本発明の廃ポリスチレン製品のリサイクル方法におけるリサイクルスチレンモノマーの製造工程の他の態様を示す概略図である。It is a schematic diagram which shows the other aspect of the manufacturing process of the recycled styrene monomer in the method of recycling a waste polystyrene product of this invention.
　以下、本発明の廃ポリスチレン製品のリサイクル方法について詳細に説明するが、以下
に記載する構成要件の説明は、本発明の一実施態様としての一例であり、これらの内容に
特定されるものではない。 Hereinafter, the method for recycling the waste polystyrene product of the present invention will be described in detail, but the description of the constituent requirements described below is an example as an embodiment of the present invention, and is not specified in these contents. ..
（本発明の廃ポリスチレン製品のリサイクル方法）
　本発明の廃ポリスチレン製品のリサイクル方法は、廃ポリスチレン製品を熱分解処理し
て、廃ポリスチレンからリサイクルスチレンモノマーを得る工程を含む。
　本発明のリサイクル方法は、廃ポリスチレン製品から、ポリスチレン製品の原料である
スチレンモノマーを製造するケミカルリサイクル方法である。
　廃ポリスチレンは、本発明のリサイクルスチレンモノマー、または石油由来のスチレン
モノマーからなるポリスチレン製品、または、マテリアルリサイクルにより得られたポリ
スチレン製品の廃棄物である。
　さらに、本発明の廃ポリスチレン製品のリサイクル方法の好ましい実施態様として、以
下の１）～４）の工程を含む廃ポリスチレン製品のリサイクル方法が挙げられる。
　１）廃ポリスチレン製品を回収する工程（以下、回収工程ともいう）
　２）回収された廃ポリスチレン製品を熱分解処理し、廃ポリスチレンからリサイクルス
チレンモノマーを得る工程（以下、リサイクルスチレンモノマーの製造工程ともいう）
　３）リサイクルスチレンモノマーを重合し、リサイクルポリスチレンを得る工程（以下
、リサイクルポリスチレンの製造工程ともいう）
　４）リサイクルポリスチレンからなるリサイクルされたポリスチレン製品を得る工程（
以下、ポリスチレン製品の製造工程ともいう）
　本発明において、リサイクルスチレンモノマーとは、リサイクルされたスチレンモノマ
ー、つまり廃ポリスチレンからリサイクル工程を経て得られたスチレンモノマーをいう。
　また、本発明において、リサイクルポリスチレンとは、リサイクルされたポリスチレン
、つまりリサイクルスチレンモノマーを重合して得られたポリスチレンまたは、マテリア
ルリサイクルにより得られたポリスチレンをいう。 (Method for recycling waste polystyrene products of the present invention)
The method for recycling a waste polystyrene product of the present invention includes a step of thermally decomposing the waste polystyrene product to obtain a recycled styrene monomer from the waste polystyrene.
The recycling method of the present invention is a chemical recycling method for producing a styrene monomer, which is a raw material for polystyrene products, from waste polystyrene products.
Waste polystyrene is the waste of the recycled styrene monomer of the present invention, the polystyrene product made of petroleum-derived styrene monomer, or the polystyrene product obtained by material recycling.
Further, as a preferred embodiment of the method for recycling waste polystyrene products of the present invention, there is a method for recycling waste polystyrene products including the following steps 1) to 4).
1) Process of collecting waste polystyrene products (hereinafter, also referred to as recovery process)
2) A process of thermally decomposing the recovered waste polystyrene product to obtain recycled styrene monomer from the waste polystyrene (hereinafter, also referred to as a manufacturing process of recycled styrene monomer).
3) A process of polymerizing recycled styrene monomer to obtain recycled polystyrene (hereinafter, also referred to as a manufacturing process of recycled polystyrene).
4) Process of obtaining recycled polystyrene products made of recycled polystyrene (
Hereinafter referred to as the manufacturing process of polystyrene products)
In the present invention, the recycled styrene monomer means a recycled styrene monomer, that is, a styrene monomer obtained from waste polystyrene through a recycling step.
Further, in the present invention, the recycled polystyrene refers to recycled polystyrene, that is, polystyrene obtained by polymerizing a recycled styrene monomer or polystyrene obtained by material recycling.
　上記４）の工程で得られたリサイクルされたポリスチレン製品（以下、リサイクルポリ
スチレン製品ともいう）は、市場に供給される。その後、不要となったリサイクルポリス
チレン製品、及び使用済みリサイクルポリスチレン製品等の廃リサイクルポリスチレン製
品は、再び回収される。
　再び回収された廃リサイクルポリスチレン製品は、２）の工程の熱分解処理に供される
。これにより、再びリサイクルスチレンモノマーを製造することができる。
　このように、１）～４）の工程を経て製造されたリサイクルポリスチレン製品は、再び
１）～４）の工程に供され、リサイクルポリスチレン製品を製造することができる。
　本発明により、廃ポリスチレン製品をリサイクルポリスチレン製品へ繰り返し製造する
ことができ、廃ポリスチレン製品の循環型リサイクルシステムの確立が可能となる。 The recycled polystyrene products obtained in the step 4) above (hereinafter, also referred to as recycled polystyrene products) are supplied to the market. After that, the recycled polystyrene products that are no longer needed and the waste recycled polystyrene products such as the used recycled polystyrene products are collected again.
The recovered waste recycled polystyrene product is subjected to the thermal decomposition treatment in the step 2). As a result, the recycled styrene monomer can be produced again.
As described above, the recycled polystyrene products manufactured through the steps 1) to 4) are again subjected to the steps 1) to 4), and the recycled polystyrene products can be manufactured.
INDUSTRIAL APPLICABILITY According to the present invention, waste polystyrene products can be repeatedly manufactured into recycled polystyrene products, and a recycling system for waste polystyrene products can be established.
　図１により、本発明のリサイクル方法の概要を説明する。
　廃ポリスチレン製品１は回収される（回収工程Ａ）。
　回収された廃ポリスチレン製品は、熱分解処理工程、油成分取得工程、及び蒸留精製工
程等の各工程が施され、リサイクルモノマー２が製造される（リサイクルスチレンモノマ
ーの製造工程Ｂ）。
　製造されたリサイクルスチレンモノマー２は重合され、リサイクルポリスチレン３が製
造される（リサイクルポリスチレンの製造工程Ｃ）。
　製造されたリサイクルポリスチレン３を利用して、各種ポリスチレン製品４が製造され
る（ポリスチレン製品の製造工程Ｄ）。
　製造されたポリスチレン製品４は、不要となった場合、廃ポリスチレン製品１として、
回収工程Ａに供することができる。
　廃ポリスチレン製品１は、本発明から得られたポリスチレン製品４、石油由来のスチレ
ンモノマーを含むポリスチレン製品、または、マテリアルリサイクルにより得られたポリ
スチレン製品の廃棄物である。
　図１で示されるように、本発明のリサイクル方法によれば、廃ポリスチレン製品の循環
型リサイクルシステムの確立が可能となる。
　以下、上記１）～４）の各工程について、詳しく説明する。 The outline of the recycling method of this invention will be described with reference to FIG.
The waste polystyrene product 1 is recovered (recovery step A).
The recovered waste polystyrene product is subjected to various steps such as a thermal decomposition treatment step, an oil component acquisition step, and a distillation refining step to produce recycled monomer 2 (recycled styrene monomer manufacturing step B).
The manufactured recycled styrene monomer 2 is polymerized to produce recycled polystyrene 3 (recycled polystyrene manufacturing step C).
Various polystyrene products 4 are manufactured using the manufactured recycled polystyrene 3 (polystyrene product manufacturing process D).
When the manufactured polystyrene product 4 is no longer needed, it is treated as waste polystyrene product 1.
It can be used for the recovery step A.
The waste polystyrene product 1 is the waste of the polystyrene product 4 obtained from the present invention, the polystyrene product containing petroleum-derived styrene monomer, or the polystyrene product obtained by material recycling.
As shown in FIG. 1, according to the recycling method of the present invention, it is possible to establish a recycling system for waste polystyrene products.
Hereinafter, each of the above steps 1) to 4) will be described in detail.
＜回収工程Ａ＞
　廃ポリスチレン製品を回収する。
　ここで、廃ポリスチレン製品とは、不要となったポリスチレン製品や使用済みポリスチ
レン製品等の廃棄されるポリスチレン製品をいう。
　回収された廃ポリスチレン製品は、上記２）の工程の熱分解処理に供される。上記２）
の工程に供される廃ポリスチレン製品は、回収後特に選別される必要はなく、回収された
全ての廃ポリスチレン製品を上記２）の工程の熱分解処理に供することができる。
　例えば、ポリスチレンの製品には、着色されている製品もあるが、マテリアルリサイク
ルにおいて何の制限もなく使用できるのは、無着色のポリスチレン製品だけである。着色
されたポリスチレン製品（例えば、黒色のポリスチレン製品）は、ハンガー等特定の用途
の製品にしかリサイクルできない。
　本発明のリサイクル方法によれば、着色されたポリスチレン製品（例えば、黒色のポリ
スチレン製品）と無着色のポリスチレン製品を分別することなく、着色されたポリスチレ
ン製品（例えば、黒色のポリスチレン製品）と無着色のポリスチレン製品とを含む廃ポリ
スチレン製品から、無着色のリサイクルポリスチレン製品を製造することができる。
　本発明のリサイクル方法によれば、無着色のポリスチレン製品も、着色された（有色の
）ポリスチレン製品も両方混在した状態で、上記２）の工程の熱分解処理に供することが
できる。
　ここで、着色された（有色の）ポリスチレン製品とは、有色に着色するために顔料等の
着色剤が組み合わされているポリスチレン製品をいう。組合せの態様は、例えば、ポリス
チレン基材への添加、着色されたラミネートフィルムの貼付などが挙げられる。
　本発明によれば、回収後、製品を色別に分別する作業を行う必要はなく、無着色のポリ
スチレン製品だけでなく、有色のポリスチレン製品もリサイクル対象とすることができる
。本発明により、回収後の分別作業に係る労力を削減することができる。また廃ポリスチ
レン製品のリサイクル利用率を向上させることができ、廃ポリスチレン製品のスチレンを
１００％リサイクルすることも期待できる。 <Recovery process A>
Collect waste polystyrene products.
Here, the waste polystyrene product refers to a discarded polystyrene product such as an unnecessary polystyrene product or a used polystyrene product.
The recovered waste polystyrene product is subjected to the thermal decomposition treatment in the step 2) above. 2) above
The waste polystyrene products used in the above step 2) do not need to be particularly sorted after recovery, and all the recovered waste polystyrene products can be subjected to the thermal decomposition treatment in the above step 2).
For example, some polystyrene products are colored, but only uncolored polystyrene products can be used without any restrictions in material recycling. Colored polystyrene products (eg, black polystyrene products) can only be recycled into products for specific purposes such as hangers.
According to the recycling method of the present invention, colored polystyrene products (for example, black polystyrene products) and uncolored polystyrene products are not separated without separating colored polystyrene products (for example, black polystyrene products) from uncolored polystyrene products. Uncolored recycled polystyrene products can be produced from waste polystyrene products, including polystyrene products.
According to the recycling method of the present invention, both the uncolored polystyrene product and the colored (colored) polystyrene product can be subjected to the thermal decomposition treatment in the step 2) above in a mixed state.
Here, the colored (colored) polystyrene product refers to a polystyrene product in which a colorant such as a pigment is combined in order to color the product in a colored manner. Examples of the combination include addition to a polystyrene base material, attachment of a colored laminated film, and the like.
According to the present invention, it is not necessary to separate the products by color after collection, and not only uncolored polystyrene products but also colored polystyrene products can be recycled. According to the present invention, it is possible to reduce the labor involved in the sorting work after collection. In addition, the recycling utilization rate of waste polystyrene products can be improved, and it can be expected that 100% of styrene of waste polystyrene products will be recycled.
＜＜粉砕工程＞＞
　回収した廃ポリスチレン製品を熱分解処理工程に供する前に、適宜必要に応じて、廃ポ
リスチレン製品を粉砕し、廃ポリスチレンの粉砕物を得る工程をさらに設けてもよい。
　つまり、廃ポリスチレン製品を粉砕し、廃ポリスチレン製品の粉砕物を得て、該粉砕物
を上記２）の工程の熱分解処理に供してもよい。 << Crushing process >>
Before the recovered waste polystyrene product is subjected to the thermal decomposition treatment step, a step of crushing the waste polystyrene product to obtain a crushed waste polystyrene product may be further provided, if necessary.
That is, the waste polystyrene product may be crushed to obtain a crushed product of the waste polystyrene product, and the crushed product may be subjected to the thermal decomposition treatment in the step 2) above.
＜リサイクルスチレンモノマーの製造工程Ｂ＞
　本発明では、ポリスチレンを熱分解することにより生じた熱分解生成物から、スチレン
モノマーを含む凝縮性オイル（本発明では、モノマー油成分ともいう）を得て、該凝縮性
オイルを精製することにより、リサイクルスチレンモノマーを得る。リサイクルスチレン
モノマーの精製方法によりリサイクルスチレンモノマー中のスチレンの純度は、異なる。
　本発明において、モノマー油成分とは、スチレンモノマーを含む油成分をいう。 <Manufacturing process B of recycled styrene monomer>
In the present invention, a condensable oil containing a styrene monomer (also referred to as a monomer oil component in the present invention) is obtained from a pyrolysis product produced by thermally decomposing polystyrene, and the condensable oil is purified. , Obtain recycled styrene monomer. The purity of styrene in the recycled styrene monomer differs depending on the purification method of the recycled styrene monomer.
In the present invention, the monomer oil component means an oil component containing a styrene monomer.
　リサイクルスチレンモノマー製造工程Ｂの好ましい実施態様としては、以下のとおりで
ある。
　廃ポリスチレン製品を熱分解処理する。これにより、モノマー油成分とガスフレア成分
とが混合された熱分解生成物が蒸気として発生する。その蒸気を凝縮分離することにより
、ガスフレア成分を除去し、モノマー油成分を得る。該モノマー油成分を蒸留精製するこ
とにより、スチレンモノマーを得る。このようにして、廃ポリスチレンからスチレンモノ
マーが製造できる。
　つまり、リサイクルスチレンモノマー製造工程Ｂの好ましい実施態様としては、熱分解
処理工程と、油成分取得工程と、蒸留精製工程とを含む製造工程が挙げられる。
　さらに、本発明では、熱分解処理工程の後に、分離工程を含む製造工程であるとより好
ましい。
　以下、リサイクルスチレンモノマー製造工程Ｂを構成する各工程について、図２を参照
しつつ、詳しく説明する。 A preferred embodiment of the recycled styrene monomer production step B is as follows.
Pyrolysis waste polystyrene products. As a result, a pyrolysis product in which the monomer oil component and the gas flare component are mixed is generated as steam. By condensing and separating the vapor, the gas flare component is removed and the monomer oil component is obtained. A styrene monomer is obtained by distilling and refining the monomer oil component. In this way, styrene monomer can be produced from waste polystyrene.
That is, a preferred embodiment of the recycled styrene monomer manufacturing step B includes a manufacturing step including a thermal decomposition treatment step, an oil component acquisition step, and a distillation refining step.
Further, in the present invention, it is more preferable that the manufacturing step includes a separation step after the thermal decomposition treatment step.
Hereinafter, each step constituting the recycled styrene monomer manufacturing step B will be described in detail with reference to FIG. 2.
＜＜熱分解処理工程＞＞
　回収された廃ポリスチレン製品１を熱分解処理する。
　図２で示すように、廃ポリスチレン製品１を熱分解装置ａを用いて、熱分解処理すると
、蒸気（分解ガス）１０が発生する。蒸気として得られるこの熱分解生成物には、モノマ
ー油成分１４とガスフレア成分１５とが含まれている。
　ここで、ガスフレア成分とは、ガス成分やコークス成分をいう。
　熱分解装置の種類としては、ポリスチレンから上述したようにモノマー油成分１４とガ
スフレア成分１５とを含む熱分解生成物を得ることができれば、特に制限はないが、例え
ば、マイクロ波を用いた熱分解装置であることが好ましい。 << Thermal decomposition process >>
The recovered waste polystyrene product 1 is thermally decomposed.
As shown in FIG. 2, when the waste polystyrene product 1 is thermally decomposed by using the thermal decomposition apparatus a, steam (decomposition gas) 10 is generated. This pyrolysis product obtained as steam contains a monomer oil component 14 and a gas flare component 15.
Here, the gas flare component means a gas component or a coke component.
The type of the thermal decomposition apparatus is not particularly limited as long as a thermal decomposition product containing the monomer oil component 14 and the gas flare component 15 can be obtained from polystyrene as described above, but for example, thermal decomposition using a microwave is used. It is preferably a device.
＜＜＜マイクロ波を用いた熱分解装置＞＞＞
　マイクロ波を用いた熱分解装置を用いてポリスチレンを熱分解する方法について、以下
説明する。
　「マイクロ波」という用語は、波長が１メートルから１ミリメートルの電磁波、または
周波数が３００ＭＨｚ（０．３ＧＨｚ）～３００ＧＨｚの電磁波を意味する。
　好ましくは、本発明での使用に適したマイクロ波は、約９１５ＭＨｚ～約２４５０ＭＨ
ｚの周波数の電磁波である。
　マイクロ波源としては、例えば、マグネトロン管が挙げられる。 <<< Thermal decomposition device using microwaves >>>
A method for thermally decomposing polystyrene using a thermal decomposition device using microwaves will be described below.
The term "microwave" means an electromagnetic wave having a wavelength of 1 meter to 1 millimeter, or an electromagnetic wave having a frequency of 300 MHz (0.3 GHz) to 300 GHz.
Preferably, the microwave suitable for use in the present invention is from about 915 MHz to about 2450 MH.
It is an electromagnetic wave with a frequency of z.
Examples of the microwave source include a magnetron tube.
　熱分解処理に供する廃ポリスチレン製品には、該廃ポリスチレン製品のマイクロ波熱分
解を開始するため、触媒を添加させることが好ましい。
　係る触媒としては、マイクロ波を吸収し、熱を廃ポリスチレン製品に伝達し、廃ポリス
チレン製品の熱分解反応に寄与すれば、特に制限はなく、目的に応じて適宜選択すること
ができるが、例えば、マイクロ波の周波数で高い誘電損失を有する化合物を含む触媒であ
ることが好ましい。
　あるいは、触媒としては、以前に行われた熱分解反応からの炭素質残留物、マイクロ波
吸収添加剤を含むセラミックビーズ、マイクロ波吸収添加剤を含むペレット、又はそれら
の組み合わせからなる触媒であってもよい。この場合、マイクロ波吸収添加剤としては、
例えば、炭化ケイ素、窒化硼素などが挙げられる。
　あるいは、触媒としては、約８０質量％～約９０質量％の炭素を含む炭素化合物からな
る触媒であってもよく、例えば、グラファイトが挙げられる。
　触媒は、触媒と廃ポリスチレン製品とを合わせた熱分解処理に供する原料中、０．５質
量％～５０質量％含まれていることが好ましく、０．５質量％～５質量％含まれているこ
とがより好ましく、０．５質量％～２．５質量％含まれていることがさらに好ましい。 It is preferable to add a catalyst to the waste polystyrene product to be subjected to the thermal decomposition treatment in order to initiate microwave thermal decomposition of the waste polystyrene product.
The catalyst is not particularly limited as long as it absorbs microwaves, transfers heat to the waste polystyrene product, and contributes to the thermal decomposition reaction of the waste polystyrene product, and can be appropriately selected depending on the intended purpose, for example. , Preferably a catalyst containing a compound having a high dielectric loss at microwave frequencies.
Alternatively, the catalyst may be a catalyst consisting of carbonaceous residues from a previous pyrolysis reaction, ceramic beads containing a microwave absorbing additive, pellets containing a microwave absorbing additive, or a combination thereof. May be good. In this case, as a microwave absorption additive,
For example, silicon carbide, boron nitride and the like can be mentioned.
Alternatively, the catalyst may be a catalyst composed of a carbon compound containing about 80% by mass to about 90% by mass of carbon, and examples thereof include graphite.
The catalyst is preferably contained in an amount of 0.5% by mass to 50% by mass, preferably 0.5% by mass to 5% by mass, in a raw material to be subjected to a thermal decomposition treatment in which the catalyst and the waste polystyrene product are combined. It is more preferable that it is contained in an amount of 0.5% by mass to 2.5% by mass.
　熱分解処理は、酸素が添加されない状況下で行われることが好ましい。
　ここで、「酸素を添加しない」とは、分子状酸素（Ｏ２）ガスを添加しないことを意味
する。
　本発明の熱分解反応では、分子状酸素（Ｏ２）ガスを添加させず、熱分解装置内の酸素
含有量が、熱分解を進行させるのに適した残量であるときに、熱分解処理が開始されるこ
とが好ましい。
　ここで、熱分解装置内に残留している酸素の所望の含有量としては、約１０体積％以下
であることが好ましく、約５体積％以下であることがより好ましい。 The thermal decomposition treatment is preferably performed in a situation where oxygen is not added.
Here, "no oxygen is added" means that no molecular oxygen (O 2 ) gas is added.
In the pyrolysis reaction of the present invention, no molecular oxygen (O 2 ) gas is added, and the pyrolysis treatment is performed when the oxygen content in the pyrolysis apparatus is a residual amount suitable for proceeding with the pyrolysis. Is preferably started.
Here, the desired content of oxygen remaining in the thermal decomposition apparatus is preferably about 10% by volume or less, and more preferably about 5% by volume or less.
　熱分解装置には、該熱分解装置をパージする嫌気性手段が設けられていてもよい。
　嫌気性手段としては、例えば、上述した不活性ガス、流体等が挙げられる。
　流体としては、水であってもよい。
　不活性ガスとしては、アルゴン、窒素、又は蒸気等が挙げられる。
　また、嫌気性手段として、真空ポンプやベンチュリー管等の真空源も挙げられる。
　嫌気性手段として、上述した不活性ガス、流体、真空源、またはそれらの組み合わせで
あってもよい。 The pyrolysis device may be provided with anaerobic means for purging the pyrolysis device.
Examples of the anaerobic means include the above-mentioned inert gas, fluid and the like.
The fluid may be water.
Examples of the inert gas include argon, nitrogen, steam and the like.
Further, as an anaerobic means, a vacuum source such as a vacuum pump or a Venturi tube can be mentioned.
The anaerobic means may be the above-mentioned inert gas, fluid, vacuum source, or a combination thereof.
　本発明において、製品に存在する初期の水の蒸発により生成される蒸気が、熱分解装置
内の雰囲気をパージして無酸素熱分解を可能にする。
　したがって、本発明では、蒸気パージ下で熱分解処理が行われることが好ましい。
　あるいは、水の蒸発による空気の適切なパージを確実にするために、所定量の水を廃ポ
リスチレン製品に添加してもよい。
　分子状酸素（Ｏ２）ガスは、熱分解装置内に加えられないが、廃棄物には大量の酸素が
含まれる場合がある。本発明において、熱分解反応の開始前に水分が蒸発するようにし、
温度が上昇すると熱分解装置内の生成された蒸気によりそこに存在する空気が排出される
ため、空気ではなく蒸気環境で熱分解反応が起こるようにしてもよい。空気が追い出され
、適切な温度および内部圧力に到達すると、熱分解装置は密閉される。本発明では、通常
嫌気性手段として行われる、窒素またはアルゴン雰囲気で行われる完全に酸素を含まない
熱分解ではなく、追加の酸素が導入されない蒸気熱分解で行われてもよい。 In the present invention, the steam generated by the initial evaporation of water present in the product purges the atmosphere in the pyrolysis apparatus and enables anoxic pyrolysis.
Therefore, in the present invention, it is preferable that the pyrolysis treatment is performed under steam purging.
Alternatively, a predetermined amount of water may be added to the waste polystyrene product to ensure proper purging of air by evaporation of water.
Molecular oxygen (O 2 ) gas is not added into the pyrolyzer, but the waste may contain large amounts of oxygen. In the present invention, the water is allowed to evaporate before the start of the thermal decomposition reaction.
When the temperature rises, the steam generated in the pyrolysis apparatus discharges the air present therein, so that the pyrolysis reaction may occur in a steam environment instead of air. When the air is expelled and reaches the proper temperature and internal pressure, the pyrolyzer is sealed. In the present invention, it may be carried out by steam pyrolysis without introduction of additional oxygen, instead of the completely oxygen-free pyrolysis performed in a nitrogen or argon atmosphere, which is usually performed as an anaerobic means.
　熱の発生を可能にするのに十分な時間のマイクロ波、及び触媒を使用して、熱分解装置
の内壁でのマイクロ波の吸収及び触媒のマイクロ波の吸収により、熱分解装置内で廃ポリ
スチレン製品が加熱され、ポリスチレンが分解される。
　廃ポリスチレンの熱分解処理温度は、約３００℃～約６５０℃であることが好ましく、
約３００℃～約４５０℃であることがより好ましい。 Waste polystyrene in the pyrolyzer by absorption of the microwave on the inner wall of the pyrolyzer and absorption of the microwave of the catalyst, using the microwave for a sufficient time to allow the generation of heat, and the catalyst. The product is heated and the polystyrene is decomposed.
The thermal decomposition treatment temperature of the waste polystyrene is preferably about 300 ° C. to about 650 ° C.
More preferably, it is from about 300 ° C to about 450 ° C.
　図２で示すように、マイクロ波を用いた熱分解装置ａを用いて廃ポリスチレン製品を熱
分解すると、上述した蒸気（モノマー油成分とガスフレア成分との混合物）１０が発生す
る。尚、装置内には、スラリー成分が残留する。蒸気１０は、凝縮器ｃを用いて、凝縮分
離されることで、モノマー油成分１４とガスフレア成分１５に分離される。
　尚、熱分解装置ａを用いて廃ポリスチレン製品を熱分解する際、図３で示すように、熱
分解装置による熱分解処理を複数回行ってもよい。熱分解処理工程を複数回設けることで
（図３では２回行っている）、蒸気１０を得るようにしてもよい。 As shown in FIG. 2, when the waste polystyrene product is thermally decomposed by using the thermal decomposition apparatus a using microwaves, the above-mentioned steam (mixture of monomer oil component and gas flare component) 10 is generated. The slurry component remains in the apparatus. The steam 10 is separated into a monomer oil component 14 and a gas flare component 15 by being condensed and separated using a condenser c.
When the waste polystyrene product is thermally decomposed by using the thermal decomposition apparatus a, the thermal decomposition treatment by the thermal decomposition apparatus may be performed a plurality of times as shown in FIG. The steam 10 may be obtained by providing the thermal decomposition treatment step a plurality of times (which is performed twice in FIG. 3).
　マイクロ波を用いた熱分解を行うことで、通常の外部ヒーターを用いた熱分解炉に比べ
、熱分解装置中のポリスチレンに内部から均一に熱を効率的に加えることが可能となり、
熱分解速度が速く、また、モノマー油成分中のスチレンモノマー純度を高くすることが可
能となる。 By performing thermal decomposition using microwaves, it is possible to efficiently apply heat uniformly from the inside to polystyrene in the thermal decomposition equipment, compared to a thermal decomposition furnace using a normal external heater.
The thermal decomposition rate is high, and the purity of the styrene monomer in the monomer oil component can be increased.
＜＜分離工程＞＞
　本発明では、熱分解処理工程により生じたスラリー成分１１に対して、分離工程を行う
ことが好ましい。
　つまり、熱分解により生じたスラリー成分に対し、分離装置を用いて、スラリー成分か
らスチレンモノマー、スチレンオリゴマー、エチルベンゼン、ベンゼンなどの軽液と、炭
化物（チャー）や無機物などを分離し、固形物を除去し、固形物が除去された清澄スラリ
ーに対し、再度熱分解装置を用いて、熱分解処理することが好ましい。
　例えば、図２で示すように、熱分解装置ａを用いてポリスチレンを熱分解した際、装置
内に生じるスラリー成分１１を、分離装置ｂを用いて処理する。分離装置ｂにより、清澄
スラリー１２と固形物（チャー／無機物）１３とに分離し、次に清澄スラリー１２を、熱
分離装置ａに再投入する。
　ここで、チャーとは、熱分解により発生した炭素質の副生成物をいう。
　尚、スラリー成分１１から清澄スラリー１２を得て、該清澄スラリー１２を熱分離装置
ａに投入する工程は、繰り返し行うことができる。
　分離装置ｂにより、廃ポリスチレン製品に含まれるリサイクルに不要な夾雑物を取り除
くことができる。夾雑物としては、例えば、廃ポリスチレン製品で使用されていたポリス
チレン製品を着色するための顔料や、製品を作製するための成形用成分等が挙げられる。
これら夾雑物を取り除く分離工程を取り入れることにより、例えば、有色のポリスチレン
製品をリサイクル対象としても、良好な色相と質のリサイクルスチレンモノマーを製造す
ることができる。無着色のポリスチレン製品だけでなく、有色のポリスチレン製品もリサ
イクル対象とする本発明のリサイクル方法においては、分離工程は有効である。
　分離工程を加えることで、良好な品質のリサイクルスチレンモノマーを収率高く製造す
ることができる。さらに、熱分解装置中に、固形物１３の堆積を抑制することができ、熱
分解炉の洗浄回数を減らすことができ、連続してモノマー油を生産することが可能となる
。 << Separation process >>
In the present invention, it is preferable to perform a separation step on the slurry component 11 generated by the thermal decomposition treatment step.
That is, for the slurry component generated by thermal decomposition, a light liquid such as styrene monomer, styrene oligomer, ethylbenzene, and benzene is separated from the slurry component by using a separation device, and a solid substance is separated from the charcoal or an inorganic substance. It is preferable that the clarified slurry from which the solid matter has been removed is thermally decomposed again using a thermal decomposition apparatus.
For example, as shown in FIG. 2, when polystyrene is thermally decomposed by using the thermal decomposition apparatus a, the slurry component 11 generated in the apparatus is treated by using the separating apparatus b. The clarified slurry 12 and the solid substance (char / inorganic substance) 13 are separated by the separating device b, and then the clarified slurry 12 is recharged into the heat separating device a.
Here, the char refers to a carbonaceous by-product generated by thermal decomposition.
The step of obtaining the clarified slurry 12 from the slurry component 11 and charging the clarified slurry 12 into the thermal separation device a can be repeated.
The separating device b can remove impurities contained in the waste polystyrene product that are unnecessary for recycling. Examples of impurities include pigments for coloring polystyrene products used in waste polystyrene products, molding components for producing products, and the like.
By incorporating a separation step for removing these impurities, for example, even if a colored polystyrene product is targeted for recycling, a recycled styrene monomer having a good hue and quality can be produced. The separation step is effective in the recycling method of the present invention in which not only uncolored polystyrene products but also colored polystyrene products are to be recycled.
By adding the separation step, a recycled styrene monomer of good quality can be produced in high yield. Further, the accumulation of the solid matter 13 in the pyrolysis apparatus can be suppressed, the number of cleanings of the pyrolysis furnace can be reduced, and the monomer oil can be continuously produced.
＜＜油成分取得工程＞＞
　廃ポリスチレンを熱分解処理することにより生成された熱分解生成物に対して、沸点の
違いを利用して凝縮分離を行い、モノマー油成分１４とガスフレア成分１５とに分離する
。そして、モノマー油成分１４を、次工程の蒸留精製工程へ供する。
　例えば、図２で示すように、熱分解処理により発生した蒸気１０を凝縮器ｃへ供する。
　凝縮器ｃは、冷却水が流通する冷却管を備え、熱分解装置ａから排出した蒸気（分解ガ
ス）を冷却して高沸点成分を凝縮分離するものである。凝縮器ｃにおいて、分離された高
沸点成分であるモノマー油成分１４は、第１の蒸留塔ｄに供給され、凝縮しない低沸点成
分のガスフレア成分１５は、凝縮器の容器外に排出される。 << Oil component acquisition process >>
The pyrolysis product produced by thermally decomposing the waste polystyrene is condensed and separated by utilizing the difference in boiling point, and separated into the monomer oil component 14 and the gas flare component 15. Then, the monomer oil component 14 is subjected to the distillation refining step of the next step.
For example, as shown in FIG. 2, the steam 10 generated by the thermal decomposition treatment is supplied to the condenser c.
The condenser c is provided with a cooling pipe through which cooling water flows, and cools the steam (decomposition gas) discharged from the thermal decomposition apparatus a to condense and separate high boiling point components. In the condenser c, the separated monomer oil component 14 which is a high boiling point component is supplied to the first distillation column d, and the gas flare component 15 which is a low boiling point component that does not condense is discharged to the outside of the container of the condenser.
　ガスフレア成分１５を除いたモノマー油成分１４に対して、蒸留精製工程へ供する前に
、再度、熱分解装置に供する工程を入れても構わない。
　例えば、モノマー油成分１４の中から、凝縮器を用いて、二量体成分を分離し、該二量
体成分に対して、熱分解装置を用いて熱分解処理を施すことにより得られたモノマー油成
分を、先に得られたモノマー油成分１４から二量体成分を除いた残りのモノマー油成分に
加えることにより、合計されたモノマー油成分を第１の蒸留塔ｄに供することができる。
これにより、リサイクルスチレンモノマーの収率を上げることができる。
　尚、本発明において、二量体成分には、二量体の他、三量体などのオリゴマーが含まれ
ていてもよい。 The monomer oil component 14 excluding the gas flare component 15 may be subjected to a step of being subjected to a thermal decomposition apparatus again before being subjected to a distillation refining step.
For example, a monomer obtained by separating a dimer component from the monomer oil component 14 using a condenser and subjecting the dimer component to a thermal decomposition treatment using a thermal decomposition apparatus. By adding the oil component to the remaining monomer oil component obtained by removing the dimer component from the previously obtained monomer oil component 14, the total monomer oil component can be provided to the first distillation column d.
This makes it possible to increase the yield of the recycled styrene monomer.
In the present invention, the dimer component may contain an oligomer such as a trimer in addition to the dimer.
＜＜蒸留精製工程＞＞
　モノマー油成分１４を蒸留塔を使用して蒸留精製を行うことにより、スチレンモノマー
と、それ以外の成分とに分離する。
　例えば、図２で示すように、蒸留塔を２つ使用する。そして、第１の蒸留塔ｄにおいて
、モノマー油１４から主にベンゼン／トルエン／エチルベンゼン成分１６を分離し、残り
の成分を第２の蒸留塔ｅに供する。次に、第２の蒸留塔ｅにおいて、二量体成分／その他
（α－メチルスチレン等）の成分１７を分離し、スチレンモノマー（いわゆるリサイクル
スチレンモノマー２）を得る。
　ここで、二量体成分には、上述したように、二量体の他、三量体などのオリゴマーが含
まれていてもよい。
　このようにして得られた本発明に係るリサイクルスチレンモノマーは、品質が良好なス
チレンモノマーである。したがって、本発明で得られたリサイクルスチレンモノマーを用
いて製造されたリサイクルポリスチレンは、ナフサ由来のポリスチレンと同等の強度、色
相を示す良好なリサイクルポリスチレンとなる。 << Distillation purification process >>
The monomer oil component 14 is separated into a styrene monomer and other components by performing distillation purification using a distillation column.
For example, as shown in FIG. 2, two distillation columns are used. Then, in the first distillation column d, mainly benzene / toluene / ethylbenzene component 16 is separated from the monomer oil 14, and the remaining components are provided to the second distillation column e. Next, in the second distillation column e, the dimer component / other component 17 (α-methylstyrene or the like) is separated to obtain a styrene monomer (so-called recycled styrene monomer 2).
Here, as described above, the dimer component may contain an oligomer such as a trimer in addition to the dimer.
The recycled styrene monomer according to the present invention thus obtained is a styrene monomer having good quality. Therefore, the recycled polystyrene produced by using the recycled styrene monomer obtained in the present invention is a good recycled polystyrene showing the same strength and hue as the polystyrene derived from naphtha.
　また、本発明では、第２の蒸留塔ｅにおいて、スチレンモノマーから分離された二量体
成分／その他（α－メチルスチレン等）の成分１７を、再度、熱分解装置に供する工程を
入れても構わない。
　例えば、図２で示すように、第２の蒸留塔ｅから、二量体成分／その他（α－メチルス
チレン等）の成分１７が分離される。
　分離された二量体成分／その他（α－メチルスチレン等）の成分１７を、再度、熱分解
装置ａに供する。このように、二量体成分／その他（α－メチルスチレン等）の成分１７
について、再度、熱分解処理を施すことにより、追加でリサイクルスチレンモノマーが得
られる。追加で得られたリサイクルスチレンモノマーと、すでに得られている図２で示す
リサイクルスチレンモノマー２とを合計すると、リサイクルスチレンモノマーの収率をさ
らに上げることができる。 Further, in the present invention, in the second distillation column e, a step of subjecting the dimer component / other (α-methylstyrene or the like) component 17 separated from the styrene monomer to the thermal decomposition apparatus again may be included. I do not care.
For example, as shown in FIG. 2, the dimer component / other (α-methylstyrene or the like) component 17 is separated from the second distillation column e.
The separated dimer component / other component 17 (α-methylstyrene or the like) is subjected to the thermal decomposition apparatus a again. As described above, the dimer component / other component (α-methylstyrene, etc.) 17
By performing the thermal decomposition treatment again, an additional recycled styrene monomer can be obtained. The yield of the recycled styrene monomer can be further increased by summing up the additionally obtained recycled styrene monomer and the already obtained recycled styrene monomer 2 shown in FIG.
　上述した、熱分解処理工程、油成分取得工程、及び蒸留精製工程を経てリサイクルスチ
レンモノマーを製造する、リサイクルスチレンモノマーの製造工程Ｂは、ＣＯ２の排出量
が抑えられた製造方法である。
　したがって、本発明のポリスチレン製品のリサイクル方法は、ライフサイクルアセスメ
ント（ＬＣＡ）評価の高い製造方法であるといえる。 The recycled styrene monomer manufacturing step B, which manufactures the recycled styrene monomer through the thermal decomposition treatment step, the oil component acquisition step, and the distillation refining step, is a manufacturing method in which CO 2 emissions are suppressed.
Therefore, it can be said that the polystyrene product recycling method of the present invention is a manufacturing method having a high life cycle assessment (LCA) evaluation.
＜＜リサイクルスチレンモノマーの特性＞＞
　本発明で得られたリサイクルスチレンモノマーは、質の良いものではあるが、実用上悪
影響のない範囲で、わずかに不純物が含まれている。
　不純物としては、トルエン、ベンゼン、クメン、二量体、三量体、エチルベンゼン、α
－メチルスチレン、ｎ－プロピルベンゼン、フェニルアセチレン等の芳香族化合物が除去
しきれずわずかにリサイクルスチレンモノマーに含まれている場合がある。
　また、不純物として、ケイ素、銅、鉄、チタン、カーボンなどの無機物が含まれている
場合もある。
　また、不純物として、１，３－シクロヘキサジエン、２－エチル－１，３－シクロヘキ
サジエン、２－ビニル－１，３－シクロヘキサジエン、２－メチル－１，３－シクロヘキ
サジエン、１，４－シクロヘキサジエン、２－エチル－１，４－シクロヘキサジエン、２
－ビニル－１，４－シクロヘキサジエン、２－メチル－１，４－シクロヘキサジエン等の
シクロヘキサジエン系化合物や、シクロヘキセン、シクロヘキセンヘキサン等のシクロヘ
キセン系化合物などの化合物がわずかに含まれている場合もある。
　リサイクルスチレンモノマーにおける上記不純物の含有量としては、上限が、通常１０
質量％以下であり、５質量％以下でもよく、３質量％以下でもよく、１質量％以下でもよ
く、また、下限は特に限定されないが、通常０質量％より多い。これらの上限と下限はい
かなる組合せでもよい。リサイクルスチレンモノマーにおける不純物の含有量は、通常０
質量％より多く１０質量％以下であり、０質量％より多く５質量％以下でもよく、０質量
％より多く３質量％以下でもよく、０質量％より多く１質量％以下でもよい。
　中でも、リサイクルスチレンモノマーにおける無機成分の含有量としては、上限は通常
０．１質量％以下であり、０．０１質量％以下でもよく、０．００１質量％以下でもよい
、また、下限は特に限定されないが、通常０質量％より多い。これらの上限と下限はいか
なる組合せでもよい。リサイクルスチレンモノマーにおける無機成分の含有量は、通常０
質量％より多く０．１質量％以下、０質量％より多く０．０１質量％以下でもよく、０質
量％より多く０．００１質量％以下でもよく、０質量％より多く１質量％以下でもよい。 << Characteristics of recycled styrene monomer >>
The recycled styrene monomer obtained in the present invention is of good quality, but contains a small amount of impurities within a range that does not adversely affect practical use.
Impurities include toluene, benzene, cumene, dimer, trimer, ethylbenzene, α
-Aromatic compounds such as methylstyrene, n-propylbenzene and phenylacetylene may not be completely removed and may be slightly contained in the recycled styrene monomer.
Inorganic substances such as silicon, copper, iron, titanium, and carbon may be contained as impurities.
As impurities, 1,3-cyclohexadiene, 2-ethyl-1,3-cyclohexadiene, 2-vinyl-1,3-cyclohexadiene, 2-methyl-1,3-cyclohexadiene, 1,4-cyclo Hexadiene, 2-ethyl-1,4-cyclohexadiene, 2
-It may contain a small amount of compounds such as cyclohexadiene compounds such as vinyl-1,4-cyclohexadiene and 2-methyl-1,4-cyclohexadiene, and cyclohexene compounds such as cyclohexene and cyclohexenehexane. ..
The upper limit of the content of the above impurities in the recycled styrene monomer is usually 10.
It may be 5% by mass or less, may be 3% by mass or less, may be 1% by mass or less, and the lower limit is not particularly limited, but is usually more than 0% by mass. These upper and lower limits may be any combination. The content of impurities in the recycled styrene monomer is usually 0.
It may be more than 0% by mass and 10% by mass or less, more than 0% by mass and 5% by mass or less, more than 0% by mass and 3% by mass or less, and more than 0% by mass and 1% by mass or less.
Among them, the upper limit of the content of the inorganic component in the recycled styrene monomer is usually 0.1% by mass or less, may be 0.01% by mass or less, may be 0.001% by mass or less, and the lower limit is particularly limited. Not done, but usually more than 0% by weight. These upper and lower limits may be any combination. The content of inorganic components in recycled styrene monomers is usually 0.
It may be more than 0.1% by mass and less than 0.1% by mass, more than 0% by mass and less than 0.01% by mass, more than 0% by mass and less than 0.001% by mass, and more than 0% by mass and less than 1% by mass. ..
＜リサイクルポリスチレンの製造工程Ｃ＞
　得られたリサイクルスチレンモノマーを重合し、リサイクルポリスチレンを得る。
　得られたリサイクルポリスチレンは、上述したように、マテリアルリサイクルで製造さ
れるポリスチレンと比べて強度が向上したリサイクルポリスチレンとなる。
　得られたリサイクルポリスチレンは、樹脂焼けによる色相の悪化が抑制されたポリスチ
レンとなる。
　スチレンモノマーの重合法としては、溶液重合法、塊状重合法、懸濁重合法、及び気相
重合法などがあり、いずれの方法も採用することができる。
　溶液重合法は、例えば、スチレンモノマーに沸点１３０℃～２００℃のエチルベンゼン
、トルエンなどの溶媒を５～２０％混合して重合する方法であり、塊状重合法は、例えば
、スチレンモノマーに触媒などを添加し加熱して重合する方法であり、懸濁重合法は、例
えば、大量の水に分散剤を用いてスチレンモノマーを粒子として分散させ、パーオキサイ
ドのような触媒を用いて重合する方法である。 <Manufacturing process C of recycled polystyrene>
The obtained recycled polystyrene monomer is polymerized to obtain recycled polystyrene.
As described above, the obtained recycled polystyrene is a recycled polystyrene having improved strength as compared with the polystyrene produced by material recycling.
The obtained recycled polystyrene is polystyrene in which deterioration of hue due to resin burning is suppressed.
Examples of the styrene monomer polymerization method include a solution polymerization method, a bulk polymerization method, a suspension polymerization method, and a gas phase polymerization method, and any of these methods can be adopted.
The solution polymerization method is a method of mixing 5 to 20% of a solvent such as ethylbenzene or toluene having a boiling point of 130 ° C. to 200 ° C. with a styrene monomer and polymerizing the styrene monomer. It is a method of adding and heating to polymerize, and the suspension polymerization method is, for example, a method of dispersing a styrene monomer as particles in a large amount of water using a dispersant and polymerizing using a catalyst such as peroxide. ..
　リサイクルスチレンモノマーを重合して得られるリサイクルポリスチレンの態様として
は、スチレン単独の重合体（スチレンホモポリマー）だけでなく、スチレンモノマーとス
チレン以外のモノマーとの共重合体（コポリマー）も含み得る。また、ブタジエンゴム等
の存在下でグラフト重合させたゴム変性ポリスチレンも含み得る。 The embodiment of the recycled polystyrene obtained by polymerizing the recycled styrene monomer may include not only a polymer of styrene alone (styrene homopolymer) but also a copolymer of a styrene monomer and a monomer other than styrene (copolymer). It may also include rubber-modified polystyrene graft-polymerized in the presence of butadiene rubber or the like.
　得られたリサイクルポリスチレンは、以下測定方法により強度を評価した場合に、優れ
た強度を示す。ナフサ由来のポリスチレンの強度を１００とした場合、マテリアルリサイ
クルで得られるポリスチレンの強度は９０程度である。ナフサ由来のポリスチレンの強度
を１００とした場合、本発明におけるリサイクルポリスチレンの強度は、下限が通常９０
よりも高く、好ましくは９５以上、より好ましくは９７以上、さらに好ましくは９９以上
であり、また、上限は特に限定されないが、通常１００以下である。これらの上限と下限
はいかなる組合せでもよい。ナフサ由来のポリスチレンの強度を１００とした場合、リサ
イクルポリスチレンの強度は１００以上でもよい。ナフサ由来のポリスチレンの強度を１
００とした場合、本発明により得られたリサイクルポリスチレンの強度は、通常９０より
大きく１００以下、好ましくは９５以上１００以下、より好ましくは９７以上１００以下
、さらに好ましくは９９以上１００以下である。 The obtained recycled polystyrene shows excellent strength when the strength is evaluated by the following measuring method. When the strength of polystyrene derived from naphtha is 100, the strength of polystyrene obtained by material recycling is about 90. When the strength of polystyrene derived from naphtha is 100, the lower limit of the strength of recycled polystyrene in the present invention is usually 90.
It is higher than, preferably 95 or more, more preferably 97 or more, still more preferably 99 or more, and the upper limit is not particularly limited, but is usually 100 or less. These upper and lower limits may be any combination. When the strength of polystyrene derived from naphtha is 100, the strength of recycled polystyrene may be 100 or more. Strength of polystyrene derived from naphtha is 1
When it is set to 00, the strength of the recycled polystyrene obtained by the present invention is usually larger than 90 and 100 or less, preferably 95 or more and 100 or less, more preferably 97 or more and 100 or less, and further preferably 99 or more and 100 or less.
　［ポリスチレン強度の測定方法］
　ポリスチレンの強度は、例えばＪＩＳ　Ｋ　７１６１－１，２に従って、引張破壊応力
で評価したり、ＪＩＳ　Ｋ　７１７１に従って、曲げ強さで評価することができる。また
、ゴム変性ポリスチレンの場合は、ＪＩＳ　Ｋ　７１１１－１に従ってシャルピー衝撃強
さで評価することもできる。 [Measurement method of polystyrene strength]
The strength of polystyrene can be evaluated by, for example, tensile fracture stress according to JIS K 7161-1, or by bending strength according to JIS K 7171. Further, in the case of rubber-modified polystyrene, it can be evaluated by Charpy impact strength according to JIS K 711-1.
　得られたリサイクルポリスチレンは、以下測定方法により色相を評価した場合に、黄色
度が抑制されるという良好な色相を示す。具体的には、黄色度（ＹＩ値）等で色相を評価
する。ＹＩ値はプラス側に大きくなるほど黄色が強く、マイナス側に大きくなるほど青色
が強いことを示す。本発明で得られるリサイクルポリスチレンのＹＩ値は、マテリアルリ
サイクルで得られるポリスチレンのＹＩ値より低く、ＹＩ値の差は通常０．１以上、好ま
しくは０．３以上、より好ましくは０．５以上、さらに好ましくは１．０以上である。Ｙ
Ｉ値の差は特に上限はない。 The obtained recycled polystyrene shows a good hue in which the yellowness is suppressed when the hue is evaluated by the following measuring method. Specifically, the hue is evaluated by the degree of yellowness (YI value) or the like. As for the YI value, the larger the positive side, the stronger the yellow color, and the larger the negative side, the stronger the blue color. The YI value of the recycled polystyrene obtained in the present invention is lower than the YI value of the polystyrene obtained by material recycling, and the difference between the YI values is usually 0.1 or more, preferably 0.3 or more, more preferably 0.5 or more. More preferably, it is 1.0 or more. Y
There is no particular upper limit to the difference in I values.
［ポリスチレンの色相の測定方法］
　ポリスチレンの色相は、例えば、ＪＩＳ　Ｋ　７３７３に従って測定することができる
。 [Measurement method of polystyrene hue]
The hue of polystyrene can be measured, for example, according to JIS K 7373.
＜ポリスチレン製品の製造工程Ｄ＞
　リサイクルポリスチレンからリサイクルポリスチレン製品を得る。
　得られたリサイクルポリスチレン製品は、上述したように、ナフサ由来のポリスチレン
と同等の強度、色相を示す良好なリサイクルポリスチレン製品となる。 <Manufacturing process D for polystyrene products>
Obtain recycled polystyrene products from recycled polystyrene.
As described above, the obtained recycled polystyrene product is a good recycled polystyrene product exhibiting the same strength and hue as naphtha-derived polystyrene.
　ポリスチレン製品の形態としては、リサイクルポリスチレンを利用したものであれば、
特に制限はなく、目的に応じて適宜選択することができる。
　例えば、ポリスチレンの他、必要に応じて、着色剤、水、有機溶剤などのその他の成分
を含有した組成物を作製することにより、例えば、コーティング剤、インキ、接着剤とし
て使用するポリスチレン製品を製造することができる。
　あるいは、リサイクルポリスチレンを含有する組成物をシート状に成形することにより
、延伸シートや発泡シート等のポリスチレン製品を製造することもできる。また、ポリス
チレンシートを成形することにより、食品包装容器（例えば、食品トレー）などのポリス
チレン製品を製造することもできる。
　さらには、リサイクルポリスチレンを含有する組成物を射出成形あるいはインジェクシ
ョンブロー成形することにより、カップやボトル等の食品容器用ポリスチレン製品を製造
することもできる。 As for the form of polystyrene products, if recycled polystyrene is used,
There are no particular restrictions, and it can be appropriately selected according to the purpose.
For example, by producing a composition containing polystyrene and other components such as colorants, water, and organic solvents as needed, polystyrene products used as, for example, coating agents, inks, and adhesives can be produced. can do.
Alternatively, polystyrene products such as stretched sheets and foamed sheets can be manufactured by molding a composition containing recycled polystyrene into a sheet shape. Further, by molding a polystyrene sheet, a polystyrene product such as a food packaging container (for example, a food tray) can be manufactured.
Furthermore, polystyrene products for food containers such as cups and bottles can be manufactured by injection molding or injection blow molding of a composition containing recycled polystyrene.
　また、一般的にマテリアルリサイクルされたプラスチックは、食品包装容器に用いる際
、内容物のマイグレーションなどが懸念され、直接食品に接触させることができないため
、用途が限定される。しかし、本発明により得られたリサイクルプラスチックは、廃ポリ
プラスチックをモノマーに分解、精製し、重合することで得られるため、直接食品に接触
することが可能となり、用途の限定がない。 In general, material-recycled plastics are limited in their use because they cannot be brought into direct contact with food due to concerns about migration of the contents when used in food packaging containers. However, since the recycled plastic obtained by the present invention is obtained by decomposing waste polyplastic into a monomer, purifying it, and polymerizing it, it can come into direct contact with food and has no limitation on its use.
　尚、上記実施態様では、廃ポリスチレンとしてホモポリマーを使用する場合について説
明したが、本発明はホモポリマーに限らず、コポリマー、すなわち廃スチレン共重合体に
も同様に適用できる。そのような廃スチレン共重合体としては、廃ゴム変性ポリスチレン
（廃ＨＩＰＳ）、廃スチレン－アクリル共重合体（廃ＡＳ樹脂）、廃スチレン－ブタジエ
ン－アクリル共重合体（廃ＡＢＳ樹脂）などがある。本発明で廃ポリスチレンとは、これ
ら共重合体を含めることができる。 In the above embodiment, the case where a homopolymer is used as the waste polystyrene has been described, but the present invention is not limited to the homopolymer and can be similarly applied to a copolymer, that is, a waste styrene copolymer. Examples of such waste styrene copolymers include waste rubber-modified polystyrene (waste HIPS), waste styrene-acrylic copolymer (waste AS resin), waste styrene-butadiene-acrylic copolymer (waste ABS resin), and the like. .. In the present invention, waste polystyrene can include these copolymers.
　以下に実施例を挙げて本発明を更に詳述するが、本発明の範囲はこれらの実施例に限定
されるものではない。 Hereinafter, the present invention will be described in more detail with reference to examples, but the scope of the present invention is not limited to these examples.
（実施例１）
　使用済みのポリスチレン製品を回収し、その後、粉砕しペレット化した。廃ポリスチレ
ンのペレット化物１ｔをマイクロ波を用いた熱分解装置に投入した。
　熱分解装置内の反応温度を３５０℃にし、触媒として廃ポリスチレンに対して２質量％
の炭化ケイ素を使用し、蒸気パージ下で、熱分解処理を行った。
　その結果、６００ｋｇの粗リサイクルスチレンモノマーが得られた（収率６０％）。精
製後のリサイクルスチレンモノマーａの純度は９５％弱であった。 (Example 1)
Used polystyrene products were collected, then ground and pelletized. 1 ton of pelletized waste polystyrene was put into a thermal decomposition apparatus using microwaves.
The reaction temperature in the pyrolysis device was set to 350 ° C, and 2% by mass with respect to waste polystyrene was used as a catalyst.
The silicon carbide was subjected to a thermal decomposition treatment under steam purging.
As a result, 600 kg of crude recycled styrene monomer was obtained (yield 60%). The purity of the recycled styrene monomer a after purification was less than 95%.
（実施例２）
　実施例１において、ガスフレア成分を除いたモノマー油成分に対して、蒸留精製工程へ
供する前に、再度、熱分解装置に供する工程を加えた以外は、実施例１と同様にして、粗
リサイクルスチレンモノマーを得た。
　その結果、８４０ｋｇの粗リサイクルスチレンモノマーが得られた（収率８４％）。精
製後のリサイクルスチレンモノマーｂの純度は９９．８％強であった。 (Example 2)
In Example 1, crude recycled styrene was obtained in the same manner as in Example 1 except that the monomer oil component excluding the gas flare component was subjected to a step of being subjected to a thermal decomposition apparatus again before being subjected to a distillation refining step. Obtained a monomer.
As a result, 840 kg of crude recycled styrene monomer was obtained (yield 84%). The purity of the recycled styrene monomer b after purification was a little over 99.8%.
（実施例３）
　実施例１において、第２の蒸留塔において、粗リサイクルスチレンモノマーから分離さ
れた二量体成分／その他（α－メチルスチレン等）の成分を、再度、熱分解装置に供する
工程を加えた以外は、実施例１と同様にして、リサイクルスチレンモノマーｃを得た。
　その結果、実施例１で分離された二量体成分／その他（α－メチルスチレン等）の成分
から、さらに２４０ｋｇの粗リサイクルスチレンモノマーが得られた。実施例１で得られ
たリサイクルスチレンモノマーａと合わせると、実施例１及び実施例３から、合計８４０
ｋｇの粗リサイクルスチレンモノマーが得られた（収率８４％）。精製後のリサイクルス
チレンモノマーｃの純度は９５％弱であった。 (Example 3)
In Example 1, except that the step of subjecting the dimer component / other (α-methylstyrene or the like) separated from the crude recycled styrene monomer to the thermal decomposition apparatus again in the second distillation column was added. , Recycled styrene monomer c was obtained in the same manner as in Example 1.
As a result, another 240 kg of crude recycled styrene monomer was obtained from the dimer component / other (α-methylstyrene or the like) component separated in Example 1. When combined with the recycled styrene monomer a obtained in Example 1, a total of 840 from Example 1 and Example 3
kg of crude recycled styrene monomer was obtained (yield 84%). The purity of the recycled styrene monomer c after purification was less than 95%.
（実施例４）
　実施例１～３で得られたリサイクルスチレンモノマーａ～ｃをそれぞれ用い、スチレン
９５部、トルエン５部からなる混合溶液を調整し、更に、有機過酸化物としてスチレンに
対し４００ｐｐｍのｔ－ブチルパーオキシベンゾエートを加え、１２０～１６０℃の連結
した管状反応器に供給して連続塊状重合を行った。重合させて得られた混合溶液を熱交換
器で２２０℃まで加熱し、５０ｍｍＨｇの減圧下で揮発性成分を除去した後、ペレット化
してリサイクルポリスチレンＡ～Ｃを得た。
　得られたそれぞれのリサイクルポリスチレンＡ～Ｃに対して、下記に記載の方法により
、強度及び色相を評価した。 (Example 4)
Using the recycled styrene monomers a to c obtained in Examples 1 to 3, respectively, a mixed solution consisting of 95 parts of styrene and 5 parts of toluene was prepared, and further, as an organic peroxide, 400 ppm of t-butylper with respect to styrene was prepared. Oxybenzoate was added and supplied to a connected tubular reactor at 120-160 ° C. for continuous bulk polymerization. The mixed solution obtained by polymerization was heated to 220 ° C. with a heat exchanger to remove volatile components under a reduced pressure of 50 mmHg, and then pelletized to obtain recycled polystyrenes A to C.
The strength and hue of each of the obtained recycled polystyrenes A to C were evaluated by the methods described below.
（比較例１）
　使用済みスチレン系樹脂組成物１００質量部を、二軸混練押出成形機を用い、シリンダ
ー温度２２０℃で溶融混練し、ストランドを水冷却後ペレタイズし、ポリスチレンＤを得
た。
　マテリアルリサイクルで得られたポリスチレンＤに対して、下記に記載の方法により、
強度及び色相を評価した。 (Comparative Example 1)
100 parts by mass of the used styrene resin composition was melt-kneaded at a cylinder temperature of 220 ° C. using a twin-screw kneading extruder, and the strands were water-cooled and then pelletized to obtain polystyrene D.
For polystyrene D obtained by material recycling, by the method described below.
Intensity and hue were evaluated.
　比較の結果、リサイクルポリスチレンＡ～Ｃは、マテリアルリサイクルで得られたポリ
スチレンＤと比較して優れた強度、及び色相を示すことが確認できた。マテリアルリサイ
クルで得られたポリスチレンＤの強度の測定値が４５ＭＰａであったのに対してリサイク
ルポリスチレンＡ～Ｃの強度の測定値は全て５０ＭＰａを示した。マテリアルリサイクル
で得られたポリスチレンＤのＹＩ値が１．０であったのに対してリサイクルポリスチレン
Ａ～Ｃは０．４を示した。 As a result of comparison, it was confirmed that the recycled polystyrenes A to C exhibited superior strength and hue as compared with the polystyrene D obtained by material recycling. The measured values of the strength of polystyrene D obtained by material recycling were 45 MPa, whereas the measured values of the strength of the recycled polystyrenes A to C were all 50 MPa. The YI value of polystyrene D obtained by material recycling was 1.0, whereas that of recycled polystyrenes A to C was 0.4.
　［ポリスチレン強度の測定方法］
　得られたペレットを用いて、射出成形機（成形温度２２０℃）にて評価用のダンベル成
形品を作製した。このダンベル成形品を用いて、引張試験を実施し、引張破壊応力を測定
した。 [Measurement method of polystyrene strength]
Using the obtained pellets, a dumbbell molded product for evaluation was produced by an injection molding machine (molding temperature 220 ° C.). A tensile test was carried out using this dumbbell molded product, and the tensile fracture stress was measured.
［ポリスチレンの色相の測定方法］
　得られたペレットを用いて、射出成形機（成形温度２２０℃）にて評価用のプレート成
形品を作製した。このプレート成形品を用いて、透過測定法によりＹＩ値を測定した。 [Measurement method of polystyrene hue]
Using the obtained pellets, a plate molded product for evaluation was produced by an injection molding machine (molding temperature 220 ° C.). Using this plate molded product, the YI value was measured by the permeation measurement method.
　本発明のリサイクル方法を用いて、廃ポリスチレンからリサイクルスチレンモノマーを
製造した場合、高収率かつ高純度でリサイクルスチレンモノマーを製造することができる
ことがわかった。
　本発明のリサイクル方法によると、廃ポリスチレンから、高品質なスチレンモノマーが
製造でき、そのリサイクルスチレンモノマーを重合して得られたリサイクルポリスチレン
は、強度及び色相に優れたものであることがわかった。
　本発明により、廃ポリスチレン製品のスチレンを１００％リサイクルすることが期待で
きる、１００％循環型ポリスチレンのリサイクルシステムが確立できる。 It was found that when the recycled styrene monomer is produced from waste polystyrene by using the recycling method of the present invention, the recycled styrene monomer can be produced with high yield and high purity.
According to the recycling method of the present invention, it was found that high-quality styrene monomer could be produced from waste polystyrene, and the recycled polystyrene obtained by polymerizing the recycled styrene monomer was excellent in strength and hue.
INDUSTRIAL APPLICABILITY According to the present invention, a 100% recycled polystyrene recycling system can be established, which can be expected to recycle 100% of styrene of waste polystyrene products.
１　　廃ポリスチレン製品
２　　リサイクルスチレンモノマー
３　　リサイクルポリスチレン
４　　ポリスチレン製品
１０　蒸気
１１　スラリー
１２　清澄スラリー
１３　固形物（チャー／無機物）
１４　モノマー油
１５　ガスフレア
１６　ベンゼン／トルエン／エチルベンゼン
１７　二量体／その他（α－メチルスチレン）
Ａ　　回収工程
Ｂ　　リサイクルスチレンモノマーの製造方法
Ｃ　　リサイクルポリスチレンの製造方法
Ｄ　　ポリスチレン製品の製造方法
ａ　　熱分解装置
ｂ　　分離装置
ｃ　　凝縮器
ｄ　　第一の蒸留塔
ｅ　　第二の蒸留塔 1 Waste polystyrene product 2 Recycled styrene monomer 3 Recycled polystyrene 4 Polystyrene product 10 Steam 11 Slurry 12 Clarified slurry 13 Solid (char / inorganic)
14 Monomer oil 15 Gas flare 16 Benzene / Toluene / Ethylbenzene 17 Dimer / Other (α-methylstyrene)
A Recovery process B Manufacturing method of recycled styrene monomer C Manufacturing method of recycled polystyrene D Manufacturing method of polystyrene product a Thermal decomposition device b Separation device c Condenser d First distillation column e Second distillation column

Claims (8)

  1. 　廃ポリスチレン製品を熱分解処理して、廃ポリスチレンからリサイクルスチレンモノマ
    ーを得る工程、
    　を含むことを特徴とする廃ポリスチレン製品のリサイクル方法。     The process of thermally decomposing waste polystyrene products to obtain recycled styrene monomer from waste polystyrene,
    A method of recycling waste polystyrene products, characterized by containing.
  2. 　前記廃ポリスチレン製品が、無着色のポリスチレン製品と有色のポリスチレン製品とを
    含む、請求項１に記載の廃ポリスチレン製品のリサイクル方法。     The method for recycling waste polystyrene products according to claim 1, wherein the waste polystyrene products include uncolored polystyrene products and colored polystyrene products.
  3. 　前記廃ポリスチレン製品を粉砕し、廃ポリスチレン製品の粉砕物を得て、前記粉砕物を
    熱分解処理する、請求項１又は２に記載の廃ポリスチレン製品のリサイクル方法。     The method for recycling a waste polystyrene product according to claim 1 or 2, wherein the waste polystyrene product is crushed to obtain a crushed product of the waste polystyrene product, and the crushed product is thermally decomposed.
  4. 　前記リサイクルスチレンモノマーを得る工程が、
    　熱分解装置を用いて、廃ポリスチレン製品を熱分解する工程、
    　前記熱分解により発生した蒸気を凝縮器に供することにより、リサイクルスチレンモノ
    マーを含む油成分とガスフレア成分とが混合された熱分解生成物から、ガスフレア成分を
    除去し、リサイクルスチレンモノマーを含む油成分を得る工程、及び
    　前記リサイクルスチレンモノマーを含む油成分に対し、蒸留塔を用いて、リサイクルス
    チレンモノマーを純度を向上させるために蒸留精製する工程、
    　を含む、請求項１から３のいずれか一項に記載の廃ポリスチレン製品のリサイクル方法
    。     The step of obtaining the recycled styrene monomer is
    The process of pyrolyzing waste polystyrene products using a pyrolysis device,
    By supplying the steam generated by the thermal decomposition to the condenser, the gas flare component is removed from the thermal decomposition product in which the oil component containing the recycled styrene monomer and the gas flare component are mixed, and the oil component containing the recycled styrene monomer is removed. The step of obtaining and the step of distilling and purifying the recycled styrene monomer in order to improve the purity of the oil component containing the recycled styrene monomer by using a distillation tower.
    The method for recycling a waste polystyrene product according to any one of claims 1 to 3, comprising the method.
  5. 　前記熱分解により生じたスラリー成分に対し、分離装置を用いて、前記スラリー成分か
    ら固形物を除去する工程、及び
    　前記固形物が除去された清澄スラリーに対し、前記熱分解装置を用いて、熱分解する工
    程、
    　をさらに含む、請求項４に記載の廃ポリスチレン製品のリサイクル方法。     A step of removing solids from the slurry component using a separation device for the slurry component generated by the thermal decomposition, and heat using the thermal decomposition device for the clarified slurry from which the solid substance has been removed. Disassembling process,
    The method for recycling a waste polystyrene product according to claim 4, further comprising.
  6. 　前記熱分解装置が、マイクロ波を用いた熱分解装置である、請求項４又は５に記載の廃
    ポリスチレン製品のリサイクル方法。     The method for recycling waste polystyrene products according to claim 4 or 5, wherein the pyrolysis device is a pyrolysis device using microwaves.
  7. 　前記リサイクルスチレンモノマーは、スチレンモノマー以外に、無機物、芳香族化合物
    、シクロヘキサジエン系化合物、及びシクロヘキセン系化合物からなる群から選択される
    少なくとも１種を含有する、請求項１から６のいずれか一項に記載の廃ポリスチレン製品
    のリサイクル方法。     One of claims 1 to 6, wherein the recycled styrene monomer contains at least one selected from the group consisting of an inorganic substance, an aromatic compound, a cyclohexadiene compound, and a cyclohexene compound in addition to the styrene monomer. How to recycle waste polystyrene products as described in.
  8. 　廃ポリスチレン製品を回収する工程、
    　回収された廃ポリスチレン製品を熱分解処理し、廃ポリスチレンからリサイクルスチレ
    ンモノマーを得る工程、
    　前記リサイクルスチレンモノマーを重合し、リサイクルポリスチレンを得る工程、及び
    　前記リサイクルポリスチレンからなるリサイクルされたポリスチレン製品を得る工程、
    　を含むことを特徴とする廃ポリスチレン製品のリサイクル方法。

          The process of collecting waste polystyrene products,
    The process of thermally decomposing the recovered waste polystyrene products to obtain recycled styrene monomer from the waste polystyrene,
    A step of polymerizing the recycled polystyrene monomer to obtain recycled polystyrene, and a step of obtaining a recycled polystyrene product made of the recycled polystyrene.
    A method of recycling waste polystyrene products, characterized by containing.
PCT/JP2021/018165 2020-05-15 2021-05-13 Method for recycling waste polystyrene products WO2021230312A1 (en)

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WO2023209180A1 (en) 2022-04-29 2023-11-02 Repsol, S.A. Method for styrene monomer production

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