Method for producing petrochemical composition, chemical recycling method, method for producing recycled chemical starting material, method for producing polymer, method for producing molded body, petrochemical composition, recycled chemical starting material, polymer, and molded body

Abstract

The following is provided as a method for producing a petrochemical composition having a low content ratio of oxygen-containing compounds.　A method for producing a petrochemical composition, said method comprising a step for thermally decomposing a resin composition containing: an ethylene-vinyl alcohol copolymer; and a nitrogen compound (A) having a density of 1.35-2.00 g / cm3 and a molecular weight of 50-1,000.

Description

Method for producing an oil-based composition, chemical recycling method, method for producing recycled chemical raw materials, method for producing a polymer, method for producing a molded article, oil-based composition, recycled chemical raw materials, polymer, and molded article

[0001] The present invention relates to a method for producing an oil-based composition, a chemical recycling method, a method for producing recycled chemical raw materials, a method for producing a polymer, a method for producing a molded article, an oil-based composition, recycled chemical raw materials, a polymer, and a molded article. More specifically, the present invention relates to a method for producing an oil-based composition, a chemical recycling method, a method for producing recycled chemical raw materials, a method for producing a polymer, a method for producing a molded article, an oil-based composition, recycled chemical raw materials, a polymer, and a molded article that reduces the content of impurities such as oxygen-containing compounds contained in the oil-based composition.

[0002] Ethylene-vinyl alcohol copolymer (hereinafter sometimes referred to as "EVOH resin") has excellent transparency, gas barrier properties such as oxygen, fragrance retention, solvent resistance, oil resistance, and mechanical strength, and is molded into films, sheets, bottles, etc., and is widely used as a packaging material for various products such as food packaging materials, pharmaceutical packaging materials, industrial chemical packaging materials, and agricultural chemical packaging materials.

[0003] In recent years, from the perspective of efficient resource utilization, there has been a growing demand for recycling used waste plastics, including EVOH resins. While thermal recycling, chemical recycling, and material recycling are known methods for recycling such waste plastics, thermal recycling accounts for the majority. However, since thermal recycling relies on recovering and utilizing the heat energy generated during incineration, there is a need for recycling methods that can reduce the environmental impact even further.

[0004] Unlike thermal recycling and material recycling, which reprocesses waste plastics into new products, chemical recycling is a method of returning high-molecular-weight plastics to a low-molecular-weight state (hydrocarbons) for reuse, and is expected to be a recycling method that can reduce the environmental impact even further. Furthermore, many polyolefins, which are commonly used in plastics, can now be recovered as naphtha raw materials (oil-based compositions) through chemical recycling.

[0005] For example, Patent Document 1 discloses a method for the chemical recycling of plastics, which involves thermally decomposing plastic waste containing olefin-based plastics and a specific amount of EVOH resin, catalytically decomposing the resulting thermal decomposition components, and recovering the decomposition oil or decomposition gas.

[0006] Japanese Patent Application Publication No. 5-345894

[0007] The present inventors have found that when plastic waste containing EVOH resin, as disclosed in Patent Document 1, is converted into an oil-based composition by thermal decomposition, not only the desired hydrocarbons are obtained, but also impurities such as oxygen-containing compounds formed from low-molecular-weight polymers of the plastic are mixed in. These impurities, such as oxygen-containing compounds, can cause corrosion of equipment or inhibit decomposition when the oil-based composition is subjected to naphtha cracking (decomposition). Therefore, we believe there is a need for an oil-based composition with a reduced content of impurities such as oxygen-containing compounds.

[0008] Therefore, the present invention provides a method for producing an oil-based composition that can reduce the content of oxygen-containing compounds contained in the oil-based composition, a chemical recycling method, a method for producing recycled chemical raw materials, a method for producing a polymer, a method for producing a molded article, an oil-based composition, recycled chemical raw materials, a polymer, and a molded article.

[0009] However, in view of these circumstances, the present inventors conducted extensive research and found that the above problem can be solved by a method for producing an oil-based composition comprising a step of thermally decomposing a resin composition containing an ethylene-vinyl alcohol copolymer and a specific nitrogen compound (A).

[0010] In other words, the present invention has the following aspects: [1] an ethylene-vinyl alcohol copolymer and a density of 1.35 to 2.00 g / cm³ ３[1] A method for producing an oil-based composition, comprising the step of thermally decomposing a resin composition containing a nitrogen compound (A) having a molecular weight of 50 to 1000. [2] The method for producing an oil-based composition according to [1], wherein the boiling point and / or decomposition point of the nitrogen compound (A) is 280°C or higher. [3] The method for producing an oil-based composition according to [1] or [2], wherein the nitrogen compound (A) contains ammonium chloride and / or histidine. [4] The method for producing an oil-based composition according to any one of [1] to [3], wherein the content of the nitrogen compound (A) is 0.1 to 10 parts by mass per 100 parts by mass of ethylene-vinyl alcohol copolymer. [5] A chemical recycling method using the method for producing an oil-based composition according to any one of [1] to [4]. [6] A method for producing a recycled chemical raw material, comprising naphtha containing the oil-based composition obtained by the method for producing an oil-based composition according to any one of [1] to [4], by naphtha cracking. [7] The method for producing a recycled chemical raw material according to [6], wherein the recycled chemical raw material contains ethylene and / or propylene. [8] A method for producing a polymer, comprising polymerizing a monomer composition containing a recycled chemical raw material obtained by the method for producing recycled chemical raw materials described in [6]. [9] A method for producing a molded article, comprising molding a resin composition containing a polymer obtained by the method for producing a polymer described in [8].

[10] An oily composition obtained by thermally decomposing a resin composition containing an ethylene-vinyl alcohol copolymer and a nitrogen compound (A), wherein the density of the nitrogen compound (A) is 1.35 to 2.00 g / cm³. ３ an oil-based composition having a molecular weight of 50 to 1000.

[11] A recycled chemical raw material obtained by naphtha containing the oil-based composition described in

[10] being subjected to naphtha cracking.

[12] A polymer obtained by polymerizing the recycled chemical raw material described in

[11] .

[13] A molded article obtained by molding a resin composition containing the polymer described in

[12] .

[0011] The present invention makes it possible to reduce the content of oxygen-containing compounds in the oil-based composition used in chemical recycling. The method for producing the oil-based composition, the chemical recycling method, the method for producing recycled chemical raw materials, the method for producing polymers, the method for producing molded articles, the oil-based composition, recycled chemical raw materials, polymers, and molded articles using this method can also reduce the content of oxygen-containing compounds in the oil-based composition.

[0012] The present invention will be described below based on examples of embodiments for carrying out the present invention. However, the present invention is not limited to the embodiments described below.

[0013] In this specification, "x and / or y (where x and y are any combination)" means at least one of x and y, and can mean x only, y only, or x and y. In this specification, when "X to Y" (where X and Y are any numbers) is used, unless otherwise specified, it includes the meaning of "greater than or equal to X and less than or equal to Y," as well as "preferably greater than X" or "preferably less than Y." In this specification, when "greater than or equal to X" (where X is any number) or "less than or equal to Y" (where Y is any number) is used, it also includes the meaning of "preferably greater than X" or "preferably less than Y." In this specification, for numerical ranges described in stages, the upper or lower limit of a numerical range in one stage can be arbitrarily combined with the upper or lower limit of a numerical range in another stage. Also, in numerical ranges described in this specification, the upper or lower limit of that numerical range can be replaced with the values ​​shown in the examples. In this specification, a preferred combination of embodiments is a more preferred embodiment. In this specification, all physical properties and characteristic values ​​are given at 23°C unless otherwise specified. When describing measurement methods, etc., based on standards in this specification, unless otherwise specified, the standards shall be those in effect as of the filing date of this application (or the priority date, if applicable). If the standards have been abolished by that date, the standards in effect as of the date of abolition shall be used.

[0014] In this specification, "main component" means a component that has a significant effect on the properties of the object unless otherwise specified, and the content of the component is usually 50% by mass or more in the object, preferably 55% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and may be 100% by mass.

[0015] A method for producing an oily composition according to one embodiment of the present invention (hereinafter sometimes referred to as "this production method") is a method for producing an oily composition comprising a step of thermally decomposing a resin composition containing an EVOH resin and a specific nitrogen compound (A), wherein the density of the nitrogen compound (A) is 1.35 to 2.00 g / cm³. ３ Furthermore, the method involves a molecular weight of 50 to 1000.

[0016] When a resin composition containing EVOH resin and a specific nitrogen compound (A) is thermally decomposed, the polymer contained in the resin composition undergoes thermal decomposition and becomes low-molecular-weight due to heating, generating oxygen-containing compounds and the like. These oxygen-containing compounds tend to cause corrosion of equipment and inhibit decomposition when naphtha containing the oil-based composition is subjected to naphtha cracking treatment. Therefore, in this manufacturing method, it has been found that heating the resin composition containing EVOH resin and a specific nitrogen compound (A) reduces the content of oxygen-containing compounds in the oil-based composition. Before describing this manufacturing method, the resin composition used in this manufacturing method will be described below.

[0017] <Resin Composition> The resin composition according to one embodiment of the present invention (hereinafter also referred to as "the resin composition") contains an EVOH resin and a specific nitrogen compound (A), and is not particularly limited as long as it contains these.

[0018] [EVOH resin] The EVOH resin used in this resin composition is typically obtained by saponifying an ethylene-vinyl ester copolymer, which is a copolymer of ethylene and vinyl ester monomers, and is a water-insoluble thermoplastic resin.

[0019] As the vinyl ester monomer, vinyl acetate is typically used due to its market availability and efficient impurity removal during manufacturing. Other vinyl ester monomers besides vinyl acetate include, for example, aliphatic vinyl esters such as vinyl formate, vinyl propionate, vinyl valerate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl caprate, vinyl laurate, vinyl stearate, and vinyl versatate, and aromatic vinyl esters such as vinyl benzoate. However, aliphatic vinyl esters having 3 to 20 carbon atoms, preferably 4 to 10 carbon atoms, and more preferably 4 to 7 carbon atoms are usually used. These are usually used individually, but multiple types may be used simultaneously as needed.

[0020] The polymerization method for copolymerizing the ethylene and vinyl ester monomer can be any known polymerization method, such as solution polymerization, suspension polymerization, or emulsion polymerization, but generally, solution polymerization using methanol as the solvent is used. Furthermore, the saponification of the obtained ethylene-vinyl ester copolymer can also be carried out by known methods. The EVOH resin produced in this way mainly consists of ethylene-derived structural units and vinyl alcohol structural units, and contains a small amount of vinyl ester structural units that remain unsaponified.

[0021] The content of ethylene structural units in the EVOH resin is preferably 20 to 60 mol%, more preferably 25 to 50 mol%, and even more preferably 25 to 35 mol%. The content of ethylene structural units can be controlled by the pressure of the ethylene when copolymerizing the vinyl ester monomer and ethylene. The content of ethylene structural units is usually, １ It is measured by 1H-NMR measurement. For example, １ 1H-NMR measurement was used, with DMSO-d as the measurement solvent. ６ A measurement method is used that employs a device and sets the measurement temperature to 50°C.

[0022] The saponification degree of the EVOH resin is preferably 90 to 100 mol%, more preferably 95 to 100 mol%, still more preferably 99 to 100 mol%. Said saponification degree can be controlled by the amount, temperature, time and other factors of the saponification catalyst (usually an alkaline catalyst such as sodium hydroxide is used) when saponifying the ethylene-vinyl ester copolymer. The saponification degree of such EVOH resin is usually １ measured by ¹H-NMR measurement. For example, １ ¹H-NMR measurement is used, DMSO-d ６ is used as the measurement solvent, and a measurement method with a measurement temperature of 50°C is employed.

[0023] The melt flow rate (MFR) (210°C, load 2160 g) of said EVOH resin is usually 0.5 to 100 g / 10 min, preferably 1 to 50 g / 10 min, more preferably 3 to 35 g / 10 min. Said MFR is an indicator of the degree of polymerization of the EVOH resin, and can be adjusted by the amount of polymerization initiator and the amount of solvent when copolymerizing ethylene and a vinyl ester monomer.

[0024] Furthermore, the EVOH resin may contain structural units derived from the following comonomers, to the extent that they do not impede the effects of the present invention (for example, 10 mol% or less of the EVOH resin).Examples of the comonomers include olefins such as propylene, 1-butene, and isobutene; hydroxyl group-containing α-olefins such as 3-buten-1-ol, 3-buten-1,2-diol, 4-penten-1-ol, and 5-hexene-1,2-diol, and their esterified and acylated derivatives; hydroxyalkylvinylidenes such as 2-methylenepropane-1,3-diol and 3-methylenepentane-1,5-diol; 1,3-diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, and 1,3-dibutyl Hydroxyalkylvinylidene diacetates such as ruoxy-2-methylenepropane; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, (anhydride) phthalic acid, (anhydride) maleic acid, (anhydride) itaconic acid, or their salts, or mono or dialkyl esters with 1 to 18 carbon atoms in the alkyl group; acrylamide, N-alkylacrylamide with 1 to 18 carbon atoms in the alkyl group, N,N-dimethylacrylamide, 2-acrylamidopropanesulfonic acid or its salts, acrylamidopropyldimethylamine or its salts or its quaternary salts Acrylamides such as: methacrylamide, N-alkylmethacrylamide with 1 to 18 C1 of the alkyl group, N,N-dimethylmethacrylamide, 2-methacrylamidepropanesulfonic acid or its salts, methacrylamidopropyldimethylamine or its salts or its quaternary salts, etc.; N-vinylamides such as N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, etc.; vinyl cyanides such as acrylonitrile, methacrylnitrile, etc.; alkyl vinyl ethers with 1 to 18 C1 of the alkyl group, hydroxyl Examples include vinyl ethers such as cyalkyl vinyl ethers and alkoxyalkyl vinyl ethers; vinyl halogenated compounds such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride, and vinyl bromide; vinyl silanes such as trimethoxyvinylsilane; allyl halogenated compounds such as allyl acetate and allyl chloride; allyl alcohols such as allyl alcohol and dimethoxyallyl alcohol; and comonomers such as trimethyl-(3-acrylamido-3-dimethylpropyl)-ammonium chloride and acrylamido-2-methylpropanesulfonic acid.These may be used alone or in combination of two or more kinds.

[0025] Further, as the EVOH resin, a "post-modified" EVOH resin obtained by esterification, urethanization, acetalization, cyanoethylation, oxyalkyleneation or the like may also be used.

[0026] Furthermore, the EVOH resin may be a mixture of EVOH resins different in the content ratio of ethylene structural units, degree of saponification, degree of polymerization, copolymerization component and the like.

[0027] The content ratio of the EVOH resin contained in the present resin composition is usually less than 100% by mass relative to the entire resin composition, preferably 99% by mass or less, more preferably 98% by mass or less. The lower limit is usually 0.01% by mass. The range of the content ratio is, for example, 0.01 to 99.9% by mass, etc.

[0028] [Nitrogen Compound (A)] The nitrogen compound (A) used in the present embodiment contains a nitrogen atom in its structure and has a density of 1.35 to 2.00 g / cm ３ , and is a compound having a molecular weight of 50 to 1000.

[0029] Examples of the nitrogen compound (A) include primary amino groups (-NH ２ ), secondary amino groups (-NH-), tertiary amino groups (see the following general formula (I)), and quaternary amino groups (see the following general formula (II)), amino compounds containing at least one of the foregoing, or ammonium salts. These may be used alone or in combination of two or more kinds.

[0030]

[0031] Among these, as the nitrogen compound (A), primary amino groups (-NH ２ )-containing amino compounds and / or ammonium salts are preferred.

[0032] The density of the nitrogen compound (A) is 1.35 to 2.00 g / cm ３ , and from the viewpoint of the effect of the present invention, it is preferably 1.38 to 1.90 g / cm ３ , more preferably 1.40 to 1.80 g / cm ３, more preferably 1.42 to 1.70 g / cm ３ , particularly preferably 1.44 to 1.60 g / cm ３ . The method for measuring density is not particularly limited as long as it is a conventionally known measurement method, and for example, density can be measured with reference to JIS K 0061:2022.

[0033] The molecular weight of the nitrogen compound (A) is 50 to 1000, preferably 55 to 800, more preferably 65 to 600, still more preferably 70 to 400, and particularly preferably 80 to 200. The molecular weight is the sum of the atomic weights of the elements constituting the compound, and is not particularly limited as long as it is a conventionally known measurement method; for example, it can be measured by a method using the freezing point depression method, or a method using liquid chromatography (HPLC) using a gel filtration column.

[0034] The boiling point and / or decomposition point of the nitrogen compound (A) is not particularly limited, but it is preferably 280°C or higher, more preferably 282 to 400°C, still more preferably 283 to 380°C, further preferably 284 to 360°C, and particularly preferably 285 to 340°C. When the boiling point and / or decomposition point is within the above range, the nitrogen compound (A) itself has improved reactivity upon heating and tends to exhibit a greater effect of reducing oxygen-containing compounds; furthermore, since it melts at the melt molding temperature of a resin (preferably EVOH resin), it tends to exhibit excellent effects.

[0035] Specific examples of the nitrogen compound (A) include amino acids such as inorganic amino compounds and organic amino compounds. These may be used alone or in combination of two or more thereof.

[0036] Examples of the inorganic amino compound include hydroxylamine, chloramine, ammonia, ammonium chloride, and the like.

[0037] Examples of the aforementioned organic amino compounds include aliphatic amines such as methanolamine, ethanolamine, dimethylamine, diethylamine, isopropylamine, butylamine, ethylenediamine, propylenediamine, diethylenetriamine, 1,2-diaminopropane, 1,3-diaminopropane, triethylenetetramine, tetraethylenepentamine, iminobispropylamine, hexamethylenediamine, 3-azahexane-1,6-diamine, 2-acrylamido-2-methylpropanesulfonic acid, 4,7-diazadecane-1,10-diamine; heterocyclic amines such as proline, hydroxyproline, ethyleneimine, morpholine, α-amino-ε-caprolactam, acetaldehyde ammonia; heterocyclic aromatic amines such as 2-undecylimidazole, pyrrolidine, piperidine, piperazine; urea, thiourea, etc. Examples include compounds containing urea bonds such as thylurea, ethylurea, dimethylurea, diethylurea, ethyleneurea (2-imidazolidinone), azodicarbonamide, glycolylurea, and acetylurea; compounds containing amide bonds such as formamide, acetamide, benzamide, oxamide, oxamic acid, succinamide, and malonamide; compounds containing imide bonds such as succinimide, phthalimide, maleimide, 1-methylol-5,5-dimethylhydantoin, and isocyanuric acid; amino acids such as alanine, valine, leucine, isoleucine, phenylalanine, tyrosine, thyroxine, methionine, cysteine, homocysteine, taurine, serine, threonine, asparagine, aspartic acid, glutamine, glutamic acid, and proline (L- and / or D-forms); and basic amino acids such as tryptophan and histidine. However, benzotriazole is not included.

[0038] Among these nitrogen compounds (A), it is preferable that the nitrogen compound (A) contains ammonium chloride and / or histidine, and more preferably that it contains ammonium chloride and / or histidine as the main component, in order to further reduce the amount of oxygen-containing compounds.

[0039] The content of nitrogen compound (A) is 0.1 to 10 parts by mass per 100 parts by mass of EVOH resin, preferably 0.3 to 8 parts by mass, more preferably 0.5 to 7 parts by mass, even more preferably 0.8 to 6 parts by mass, and particularly preferably 1 to 5 parts by mass. A content of nitrogen compound (A) above the lower limit tends to reduce the proportion of oxygen-containing compounds in the oil-based composition. Furthermore, a content below the upper limit tends to make it easier to control the nitrogen atom content in the resulting oil-based composition to a degree that prevents corrosion and decomposition inhibition of equipment during naphtha cracking.

[0040] The content of nitrogen compound (A) is typically 0.05 to 15% by mass of the entire resin composition, preferably 0.1 to 12% by mass, more preferably 0.3 to 10% by mass, even more preferably 0.5 to 8% by mass, and particularly preferably 0.8 to 5% by mass. Within this range, the content of oxygen-containing compounds tends to be effectively reduced. The method for measuring the nitrogen compound (A) content is not particularly limited as long as it is a conventionally known measurement method, but for example, the nitrogen compound (A) content is １４ The nitrogen content can be calculated by performing CHN analysis using a measurement method with N as the nucleus or by using an elemental analyzer.

[0041] This resin composition may contain thermoplastic resins and compounding agents other than EVOH resin and nitrogen compound (A). In other words, this resin composition may be a thermoplastic resin composition containing EVOH resin.

[0042] [Thermoplastic resins other than EVOH resin and nitrogen compound (A)] The thermoplastic resins other than EVOH resin and nitrogen compound (A) include known thermoplastic resins, such as polyethylene resins such as linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, high-density polyethylene, ethylene-propylene (block and random) copolymers, and ethylene-α-olefin (α-olefin with 4 to 20 carbon atoms) copolymers; polypropylene resins such as polypropylene and propylene-α-olefin (α-olefin with 4 to 20 carbon atoms) copolymers; (unmodified) polyolefin resins such as polybutene, polypentene, and polycyclic olefin resins (polymers having a cyclic olefin structure in at least one of the main chain and side chains); and these polyolefins Examples include polyolefin resins in a broad sense, such as modified olefin resins including unsaturated carboxylic acid-modified polyolefin resins obtained by grafting vinyl resins with unsaturated carboxylic acids or their esters, ionomers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers, polyester resins, polyamide resins (including copolymerized polyamides), polyvinyl chloride, polyvinylidene chloride, acrylic resins, polystyrene resins, vinyl ester resins, polyester elastomers, polyurethane elastomers, polystyrene elastomers, halogenated polyolefins such as chlorinated polyethylene and chlorinated polypropylene, aromatic or aliphatic polyketones, etc. These can be used individually or in combination of two or more. Among these, polyamide resins are preferred. Note that linear low-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, medium-density polyethylene, and high-density polyethylene are terms commonly used to describe types of polyethylene.

[0043] If the resin composition contains thermoplastic resins other than the EVOH resin and nitrogen compound (A), the proportion of these resins is usually 0.01 to 99% by mass, preferably 0.1 to 90% by mass, and more preferably 1 to 85% by mass, relative to the entire resin composition.

[0044] [Compounding Agents] Examples of compounding agents include those generally used in thermoplastic resins, such as inorganic double salts, plasticizers, oxygen absorbers, heat stabilizers, light stabilizers, ultraviolet absorbers, colorants, antistatic agents, surfactants, lubricants, antibacterial agents, antiblocking agents, fillers, compatibilizers, etc. These can be used individually or in combination of two or more.

[0045] Examples of the inorganic double salt include hydrotalcite. Examples of the plasticizer include ethylene glycol, glycerin, aliphatic polyhydric alcohols such as hexanediol. Examples of the oxygen absorber include inorganic oxygen absorbers such as aluminum powder and potassium sulfite, ascorbic acid, fatty acid esters and metal salts of ascorbic acid, polyhydric phenols such as gallic acid and hydroxyl group-containing phenol aldehyde resins, terpene compounds, blends of tertiary hydrogen-containing resins and transition metals (e.g., a combination of polypropylene and cobalt), blends of carbon-carbon unsaturated bond-containing resins and transition metals (e.g., a combination of polybutadiene and cobalt), photo-oxidative decomposition resins (e.g., polyketones), anthraquinone polymers (e.g., polyvinylanthraquinone), and polymeric oxygen absorbers such as those obtained by adding photoinitiators (such as benzophenone) or other antioxidants and deodorants (such as activated carbon) to these formulations.

[0046] If the resin composition contains a compounding agent, its content is usually 20% by mass or less of the total resin composition, preferably 15% by mass or less, and more preferably 10% by mass or less. The lower limit is 0% by mass, and the range of its content is, for example, 0 to 20% by mass.

[0047] [Shape of the resin composition] The shape of the resin composition is not particularly limited, but examples of preferred shapes include pellets, films, sheets, molded articles, and crushed materials, scraps, and irregularly shaped products obtained by crushing them.

[0048] The origin of the aforementioned pellets, films, sheets, molded articles, etc., is not particularly limited, but is preferably derived from post-consumer recycling (PCR) or post-industrial recycling (PIR).

[0049] When the resin composition is in the form of a molded article, the molded article may be a single-layer molded article consisting only of a layer containing EVOH resin (hereinafter referred to as the "EVOH resin layer"), or it may be a multilayer laminated molded article in which the EVOH resin layer and a base resin layer mainly composed of a thermoplastic resin other than EVOH resin (hereinafter, the resin used for the base material is referred to as the "base resin") are laminated together. Examples of the base resin include thermoplastic resins other than the aforementioned EVOH resin.

[0050] Furthermore, the multilayer laminate may have multiple EVOH resin layers and base resin layers, and an adhesive resin layer containing an adhesive resin may be interposed between the EVOH resin layer and the base resin layer as needed.

[0051] The adhesive resin is appropriately selected depending on the base resin, and typically includes modified polyolefin polymers containing carboxyl groups obtained by chemically bonding an unsaturated carboxylic acid or its anhydride to a polyolefin resin by addition reaction, graft reaction, or the like.

[0052] Examples of the modified polyolefin polymers containing the carboxyl group include maleic anhydride graft-modified polyethylene, maleic anhydride graft-modified polypropylene, maleic anhydride graft-modified ethylene-propylene (block and random) copolymer, maleic anhydride graft-modified ethylene-ethyl acrylate copolymer, maleic anhydride graft-modified ethylene-vinyl acetate copolymer, maleic anhydride-modified polycyclic olefin resin, and maleic anhydride graft-modified polyolefin resin. These can be used individually or in combination of two or more.

[0053] Furthermore, if the shape of the resin composition is a molded body, the molded body may be made of a single-layer film or a multi-layer film.

[0054] Furthermore, the resin composition may be subjected to cutting or pulverization before thermal decomposition. The methods for cutting and pulverization are not particularly limited. For example, a cutting method may be using a cutting machine such as a slitter or shredder. For example, a pulverization method may be using a pulverizer, or a method of pulverizing in stages using multiple pulverizers, such as coarsely pulverizing with a primary pulverizer and then further finely pulverizing with a secondary pulverizer. These cutting and pulverization processes may be used individually or in combination of two or more.

[0055] In this manufacturing method, the resin composition is first thermally decomposed to obtain the oil-based composition. However, if the resin composition contains a thermoplastic resin containing chlorine, such as polyvinyl chloride, it is preferable to perform a desalination treatment before thermal decomposition.

[0056] Examples of the desalination treatment methods include the known twin-screw extruder dechlorination method. The twin-screw extruder dechlorination method involves using a twin-screw extruder to melt the resin composition at 200 to 230°C, and then extruding it at approximately 350°C to separate hydrogen chloride. The desalination-treated resin composition is then subjected to thermal decomposition.

[0057] <This manufacturing method> This manufacturing method comprises a step of thermally decomposing the resin composition to obtain an oil-based composition. That is, EVOH resin and 1.35 to 2.00 g / cm³ ３ The method further includes a step of thermally decomposing a resin composition containing a nitrogen compound (A) having a molecular weight of 50 to 1000. The step of thermally decomposing the resin composition will be described below.

[0058] The temperature used for the thermal decomposition is preferably 240 to 800°C, more preferably 250 to 600°C, and even more preferably 300 to 500°C. When the heating temperature is within this range, there is a tendency to reduce the amount of oxygen-containing compounds contained in the oil-based composition.

[0059] The heating time is usually 10 minutes or more, preferably 0.2 hours or more, and more preferably 0.3 hours or more. There is no particular upper limit, but it should be carried out until the resin composition is completely thermally decomposed, but it is usually 24 hours or less, preferably 12 hours or less, and more preferably 6 hours or less. The range of the heating time is, for example, 10 minutes to 24 hours.

[0060] The apparatus used in the aforementioned pyrolysis process is not particularly limited, and examples include apparatus commonly used for the oil conversion of polyolefin resins, such as an apparatus equipped with a pyrolysis tank for gasifying the resin composition and a coagulation means for cooling the decomposition gas from the pyrolysis tank to produce oil.

[0061] Methods for thermally decomposing this resin composition include, for example, (i) decomposition by electric furnace, (ii) decomposition by iron acetate solution, and (iii) decomposition by fluid contact device. These methods can be used individually or in combination of two or more. These methods will be described below.

[0062] [(i) Method of decomposition using an electric furnace] The method of decomposition using an electric furnace involves filling an electric furnace (thermal decomposition chamber) equipped with a heater with the resin composition and heating it with the heater.

[0063] The heating temperature is typically 240 to 800°C, preferably 250 to 600°C, and more preferably 300 to 500°C. When the heating temperature is within the above range, there is a tendency to reduce the content of oxygen-containing compounds in the oil-based composition. Furthermore, when the temperature is above the lower limit, there is a tendency to shorten the decomposition time, and when the temperature is below the upper limit, there is a tendency to reduce the amount of wax contained in the resulting oil-based composition.

[0064] Furthermore, heating by the heater may be carried out in two or more temperature ranges from the viewpoint of decomposition efficiency. When heating in two or more temperature ranges, for example, it is preferable to heat at 240 to 450°C in the first stage to remove the resulting gas, and then raise the temperature to a higher temperature than the first stage, exceeding 400°C, to completely thermally decompose (second stage heating).

[0065] When decomposing the resin composition using the aforementioned electric furnace method, it is preferable to do so while injecting a carrier gas.

[0066] Examples of the carrier gas include noble gases such as helium, nitrogen, and carbon dioxide. Among these, helium and nitrogen are preferred, and helium is more preferred.

[0067] The flow rate of the carrier gas varies depending on the size of the pyrolysis vessel and is not particularly limited, but for example, if the capacity of the pyrolysis vessel is 500 mL, it is 0.05 to 0.5 L / min.

[0068] The aforementioned method of decomposition using an electric furnace may also involve catalytic decomposition using a catalyst.

[0069] Examples of the catalysts mentioned above include FCC catalysts and FCC waste catalysts. These can be used individually or in combination of two or more types.

[0070] The aforementioned FCC catalyst is a synthetic zeolite-based solid acid catalyst used in the fluid catalytic cracking (FCC) process of petroleum, and Al ２ O ３ The main component is [a certain substance], to which small amounts of Na, Fe, C, V, Ni, Sb, etc. are added. Furthermore, the FCC spent catalyst is a regenerated FCC catalyst. These FCC catalysts and FCC spent catalysts have an average specific gravity of 0.74 to 0.91, which is almost the same as the resin composition, and can therefore be thoroughly mixed with the resin composition in the pyrolysis tank.

[0071] The average particle size of the FCC catalyst and FCC waste catalyst is typically 40 to 80 μm. This average particle size can be measured using a laser diffraction particle size distribution analyzer or the like.

[0072] Furthermore, the amount of FCC catalyst and FCC waste catalyst used is usually 5 to 35 parts by mass, preferably 10 to 30 parts by mass, and more preferably 15 to 25 parts by mass, per 100 parts by mass of the resin composition.

[0073] In this way, the decomposed resin composition is gasified, generating decomposition gas. By recovering this decomposition gas, an oily composition can be obtained. The decomposition gas may also be recovered after being cooled to below its dew point and liquefied using known flocculation methods.

[0074] Furthermore, if the apparatus used in the decomposition method using an electric furnace is equipped with a cooler, it is also preferable to cool the obtained decomposition gas with the cooler. For example, it is also preferable to cool the gaseous oil composition obtained by the first heating, second heating, etc., with the cooler. The temperature of the cooler is usually 0 to 50°C, preferably 10 to 45°C, more preferably 20 to 40°C, and even more preferably 30 to 35°C. By cooling the gas obtained by the first heating, second heating, etc., with the cooler, gaseous components having a boiling point higher than the cooler temperature liquefy and return to the pyrolysis tank, thus tending to reduce the amount of impurities contained in the gas.

[0075] [(ii) Method of decomposition using iron acetate solution] As an example of a method of decomposition using iron acetate solution, the resin composition is brought into contact with the iron acetate solution heated at normal pressure and in the absence of air in a thermal decomposition tank to decompose the resin composition.

[0076] The wood acetic acid is the supernatant liquid produced when wood is dry-distilled, and the iron acetate solution is a liquid with a pH of 1.5 to 7 obtained by dissolving iron in wood vinegar. The wood vinegar contains wood-derived organic acids (such as acetic acid), alcohols, carbonyl compounds, and aromatic compounds (such as phenols and furans).

[0077] The temperature of the iron acetate solution is preferably 240 to 800°C, more preferably 300 to 500°C, even more preferably 400 to 480°C, and particularly preferably 410 to 430°C. When the heating temperature is within the above range, there is a tendency to reduce the content of oxygen-containing compounds in the oil-based composition. Furthermore, when the temperature is above the lower limit, there is a tendency to shorten the decomposition time, and when the temperature is below the upper limit, there is a tendency to reduce the amount of wax contained in the resulting oil-based composition.

[0078] The amount of the iron acetate solution is typically 10 to 40 parts by mass, preferably 15 to 35 parts by mass, and more preferably 20 to 25 parts by mass, per 100 parts by mass of the resin composition, from the viewpoint of thermal decomposition efficiency.

[0079] Furthermore, the amount of iron acetate solution is preferably 20 to 60% by volume relative to the internal volume of the pyrolysis tank. When the amount of iron acetate solution is above the lower limit, it is possible to ensure sufficient contact between the resin composition and the iron acetate solution, and the processing time tends to be shortened. When the amount is below the upper limit, it is not necessary to frequently discharge the iron acetate solution and decomposition residue, and the work tends to be simplified.

[0080] As mentioned above, the decomposition of the resin composition must be carried out in the absence of air. Therefore, it is preferable to decompose this resin composition while injecting a carrier gas.

[0081] Examples of the carrier gas include noble gases such as helium, nitrogen, and carbon dioxide. Among these, helium and nitrogen are preferred, and helium is more preferred.

[0082] The flow rate of the carrier gas varies depending on the size of the pyrolysis vessel and is not particularly limited, but for example, if the capacity of the pyrolysis vessel is 500 mL, it is 0.05 to 0.5 L / min.

[0083] In this way, the decomposed resin composition is gasified, generating decomposition gas. By recovering this decomposition gas, an oily composition can be obtained. Alternatively, the decomposition gas may be cooled to below its dew point and liquefied using known flocculation methods before being recovered.

[0084] Furthermore, the oily composition derived from the resin composition obtained by this method tends to be acidic because it contains components derived from iron acetate solution. Therefore, if the oily composition derived from the resin composition is acidic, it is preferable to neutralize it. Known methods can be used as the neutralization method.

[0085] [(iii) Decomposition method using a fluid contact apparatus] The fluid contact apparatus can be an apparatus commonly used in the field of petroleum refining, and basically comprises a reaction tower (reactor), a catalyst / product oil separator, a section for removing oil from the catalyst surface, and a catalyst regeneration tower as a single unit, with the catalyst circulating within this system.

[0086] The disassembly method using a fluid contact device is not particularly limited, but examples include the UOP type from UOP Corporation, the Ultra Orthoflow type from M. W. Kellogg Corporation, and the R2R type from IFP Corporation.

[0087] The processing conditions include a reactor temperature of typically 240 to 800°C, preferably 250 to 600°C, and more preferably 300 to 500°C. When the temperature is within this range, there is a tendency to reduce the content of oxygen-containing compounds in the oil-based composition.

[0088] Furthermore, other processing conditions typically used in fluid catalytic cracking of petroleum are applicable. For example, a reactor pressure of approximately 0.1 to 3.0 kg / cm². ２ G. Mass ratio of catalyst to EVOH resin (catalyst / EVOH resin): approximately 4-8; Catalyst regeneration tower temperature: approximately 500-800°C; Catalyst regeneration tower pressure: approximately 0.1-3.0 kg / cm² ２ It is G.

[0089] Examples of the catalyst include the aforementioned FCC catalyst and FCC waste catalyst. These can be used individually or in combination of two or more types.

[0090] These methods can be used to obtain an oily composition.

[0091] [Distillation Process] It is preferable to distill the obtained oily composition to remove impurities such as water and tar. In other words, it is preferable that this manufacturing method includes a distillation process in the process of obtaining the oily composition.

[0092] For example, the distillation conditions in the aforementioned distillation process include a pressure of 100 to 760 mmHg. The distillation temperature is preferably 70 to 250°C, more preferably 80 to 230°C, and even more preferably 90 to 210°C. When the distillation conditions are within the above range, there is a tendency to obtain an oil-based composition with fewer impurities.

[0093] Furthermore, the resulting oily composition may be subjected to centrifugation or other methods to remove impurities such as water and tar.

[0094] <Oil-based composition> In this way, an oil-based composition (hereinafter sometimes referred to as "this oil-based composition") which is one embodiment of the present invention is obtained.

[0095] This oil-based composition contains a low concentration of oxygen-containing compounds because the raw material resin composition contains a specific nitrogen compound (A). This is because, when the resin composition contains EVOH resin, the specific nitrogen compound (A) reacts with aldehydes and ketones contained in the thermal decomposition products derived from the EVOH resin, producing imines and water. It is presumed that removing the resulting water reduces the concentration of oxygen-containing compounds in the oil-based composition.

[0096] Furthermore, the resulting oil-based composition may be subjected to a hydrogenation reaction using a hydrogenation catalyst used in the catalytic hydrogenation of petroleum. By performing a hydrogenation reaction, it tends to be possible to adjust the content ratio of oxygen-containing compounds in the oil-based composition.

[0097] The oxygen-containing compound content in the oil-based composition can be considered as the oxygen atom content, which is preferably 80,000 ppm or less, and more preferably 70,000 ppm or less. The lower limit of the oxygen atom content is not particularly limited; the lower the amount, the better, but it is usually 10 ppm or more. The range of this content is, for example, 10 to 80,000 ppm. When the oxygen atom content is within this range, there is a tendency to further reduce the oxygen-containing compound content in the oil-based composition.

[0098] Furthermore, the nitrogen-containing compound content in the oil-based composition can be considered as the nitrogen atom content. From the viewpoint of preventing corrosion and decomposition inhibition of equipment during naphtha cracking, the nitrogen atom content is preferably less than 20,000 ppm, more preferably 15,000 ppm or less, and even more preferably 13,000 ppm or less relative to the oil-based composition. The lower limit of the nitrogen atom content is not particularly limited, and the lower the better, but it is usually 10 ppm or more. The range of this content is, for example, 10 ppm or more and less than 20,000 ppm.

[0099] The proportions of oxygen and nitrogen atoms can be determined, for example, by measuring them using an elemental analyzer.

[0100] This liquefied composition can be used as a naphtha raw material. Furthermore, recycled chemical raw materials can be obtained by subjecting naphtha containing the liquefied composition to a conventionally known naphtha cracking treatment.

[0101] This oil-based composition has a low content of oxygen-containing compounds and is less likely to cause corrosion of equipment or inhibit decomposition during naphtha cracking, thus enabling the stable production of recycled chemical raw materials. Examples of recycled chemical raw materials obtained from naphtha containing the oil-based composition include ethylene, propylene, 1-butene, butadiene, isoprene, benzene, toluene, xylene, styrene, and other unsaturated hydrocarbons that are useful as petrochemical raw materials. Among these, ethylene and / or propylene are preferred because they can be used as raw materials for a wide range of products. That is, the recycled chemical raw materials may contain ethylene and / or propylene, or they may contain a mixture thereof, but it is preferable that they contain ethylene and / or propylene as the main component. In addition, other unsaturated hydrocarbons may be contained to the extent that they do not impair the effects of the present invention. The above ethylene and / or propylene is more preferably ethylene or propylene, with ethylene being the most preferred.

[0102] The obtained recycled chemical raw material is preferably used as a monomer composition containing the recycled chemical raw material. The monomer composition contains the recycled chemical raw material as an essential component. The monomer composition may also contain other components as long as they do not impair the effects of the present invention. Examples of other components include monomers other than recycled chemical raw materials and compounding agents as described in the resin composition. Examples of monomers other than recycled chemical raw materials include monomers of petrochemical raw materials and monomers obtained by reacting recycled chemical raw materials. Examples of monomers obtained by reacting recycled chemical raw materials include ethylene vinyl acetate monomer.

[0103] Furthermore, the monomer composition may be polymerized to obtain a resin composition containing a polymer. Conventional polymerization methods may be used for polymerizing the monomer composition. Examples of the polymer include ethylene-vinyl acetate copolymers, and the obtained ethylene-vinyl acetate copolymer may be saponified to obtain an EVOH resin.

[0104] Furthermore, this resin composition may be molded to obtain a molded article. Conventional molding methods may be used for molding the resin composition.

[0105] Thus, the embodiments of the present invention allow for the production of an oil-based composition from a resin composition containing EVOH resin and a specific nitrogen-containing compound (A). Since the obtained oil-based composition has a low content of oxygen-containing compounds, it is possible to stably obtain recycled chemical raw materials, subsequent polymers, and molded articles, making it suitable as a chemical recycling method.

[0106] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. In the examples, "parts" and "%" refer to mass.

[0107] Prior to the examples, the following compounds and resins were prepared. First, the following nitrogen compound (A) was prepared: Nitrogen compound (A1): Ammonium chloride manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., density: 1.53 g / cm³ ３Molecular weight: 53 g / mol, decomposition point: 338°C. Nitrogen compound (A2): L-histidine, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., density: 1.45 g / cm³. ３ Molecular weight: 155 g / mol, decomposition point: 287°C. Nitrogen compound (A3): Pyridine manufactured by Fujifilm Wako Pure Chemical Industries, Density: 0.982 g / cm³ ３ Molecular weight: 79 g / mol, boiling point: 115.2°C. Nitrogen compound (A4): ε-caprolactam, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., density: 1.01 g / cm³. ３ Molecular weight: 113 g / mol, boiling point: 269°C. Nitrogen compound (A5): Urea manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., density: 1.32 g / cm³. ３ , molecular weight 60g / mol, decomposition point: 160°C

[0108] Next, the following resin was prepared: • EVOH resin: SoarnoL (registered trademark) DC3203RB, manufactured by Mitsubishi Chemical Corporation: Ethylene structural unit content 32 mol%, density 1.19 g / cm³ ３ , degree of saponification 99.9 mol%

[0109] <Example 1> 100 parts of EVOH resin pellets containing 32 mol% ethylene structural units were dry-blended with 5 parts of nitrogen compound (A1), and the mixture was melt-kneaded at 190°C for 2 minutes using a plastograph (Bravender) to obtain a resin composition. 0.5 mg of the obtained resin composition was placed in a Heartcut EGA-MS pyrosizer, and the decomposition gas generated when the temperature was raised using the following pyrosizer apparatus and conditions was cooled to -195°C and recovered as an oil composition. The oil composition was separated using the following GC / MS apparatus and conditions, and the proportion (ppm) of oxygen-containing compounds in the oil composition was measured. The results are shown in Table 1. [Pyrosizer equipment and conditions] ・Pyrolysis equipment: Frontier Labs multi-shot pyrosizer (EGA / PY-3030D) ・Pyrolysis conditions: 200°C (0 min) → heating at 10°C / min (30 min) → 500°C (0 min) Gas trap temperature: -195°C [GC / MS equipment and conditions] ・GC-MS analyzer: Agilent "GC7890A" / Agilent "MS5975C" ・Separation column: DB-Heavy WAX, length 60 m, inner diameter 0.25 mm, film thickness 0.50 μm ・Carrier gas: Helium ・Inlet temperature: 270°C ・Column temperature: 40°C (3 min) → 270°C (10 min), heating rate 10°C / min (23 min) ・Split ratio: 50:1 • Measurement mass range: 15 to 400

[0110] <Example 2> Except that nitrogen compound (A) was changed to L-histidine, nitrogen compound (A2), in the same manner as in Example 1, a resin composition and an oil-based composition were obtained, and the percentage of oxygen-containing compounds in the oil-based composition was measured. The results are shown in Table 1.

[0111] <Comparative Example 1> A resin composition and an oil-based composition were obtained in the same manner as in Example 1, except that nitrogen compound (A) was not used. The results of measuring the proportion of oxygen-containing compounds in the oil-based composition are shown in Table 1.

[0112] <Comparative Example 2> A resin composition and an oil-based composition were obtained in the same manner as in Example 1, except that nitrogen compound (A) was changed to pyridine, which is nitrogen compound (A3). The results of measuring the proportion of oxygen-containing compounds in the oil-based composition are shown in Table 1.

[0113] <Comparative Example 3> Except that nitrogen compound (A) was changed to ε-caprolactam, nitrogen compound (A4), in the same manner as in Example 1, a resin composition and an oil-based composition were obtained, and the percentage of oxygen-containing compounds in the oil-based composition was measured. The results are shown in Table 1.

[0114] <Comparative Example 4> Except that nitrogen compound (A) was changed to urea (nitrogen compound (A5)) in Example 1, a resin composition and an oil-based composition were obtained in the same manner as in Example 1, and the percentage of oxygen-containing compounds in the oil-based composition was measured. The results are shown in Table 1.

[0115]

[0116] From the results in Table 1, the liquefied compositions obtained from the resin compositions containing EVOH resin and nitrogen compound (A) in Examples 1 and 2 had a lower content of oxygen-containing compounds, which are thought to cause corrosion and decomposition inhibition of equipment during naphtha cracking, compared to Comparative Examples 1 to 4. Thus, by using this liquefied composition in which the content of impurities such as oxygen-containing compounds has been sufficiently reduced, it is possible to minimize the influence of impurities in the recycled chemical raw materials, polymers, and molded articles obtained therefrom, and this will greatly contribute to suppressing corrosion and decomposition inhibition of equipment during naphtha cracking.

[0117] While the above embodiments illustrate specific forms of the present invention, these embodiments are merely illustrative and should not be interpreted restrictively. Various modifications that are obvious to those skilled in the art are intended to fall within the scope of the present invention.

[0118] This manufacturing method and this oil-based composition can reduce the proportion of oxygen-containing compounds in the oil-based composition during chemical recycling. Therefore, they are less likely to cause corrosion or inhibit decomposition of equipment during naphtha cracking, making them suitable for use in chemical recycling.

Claims

1. Ethylene-vinyl alcohol copolymer with a density of 1.35–2.00 g / cm³ ３ A method for producing an oily composition, comprising the step of thermally decomposing a resin composition containing a nitrogen compound (A) having a molecular weight of 50 to 1000.

2. A method for producing the oily composition according to claim 1, wherein the boiling point and / or decomposition point of the nitrogen compound (A) is 280°C or higher.

3. A method for producing the oil-based composition according to claim 1, wherein the nitrogen compound (A) comprises ammonium chloride and / or histidine.

4. The method for producing the oily composition according to claim 1, wherein the content of the nitrogen compound (A) is 0.1 to 10 parts by mass per 100 parts by mass of the ethylene-vinyl alcohol copolymer.

5. A chemical recycling method using a method for producing an oil-based composition according to any one of claims 1 to 4.

6. A method for producing recycled chemical raw materials, comprising subjecting naphtha containing an oil-based composition obtained by the method for producing an oil-based composition according to any one of claims 1 to 4 to naphtha cracking to obtain recycled chemical raw materials.

7. The method for producing a recycled chemical raw material according to claim 6, wherein the recycled chemical raw material comprises ethylene and / or propylene.

8. A method for producing a polymer, comprising polymerizing a monomer composition containing a recycled chemical raw material obtained by the method for producing a recycled chemical raw material described in claim 6.

9. A method for producing a molded article, comprising molding a resin composition containing a polymer obtained by the polymer production method described in claim 8 to obtain a molded article.

10. An oily composition obtained by thermally decomposing a resin composition containing an ethylene-vinyl alcohol copolymer and a nitrogen compound (A), wherein the density of the nitrogen compound (A) is 1.35 to 2.00 g / cm³. ３ an oil-based composition having a molecular weight of 50 to 1000.

11. A recycled chemical raw material obtained by naphtha containing the oil-based composition described in claim 10, through naphtha cracking.

12. A polymer obtained by polymerizing the recycled chemical raw material described in claim 11.

13. A molded article obtained by molding a resin composition containing the polymer described in claim 12.

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