Method for processing resin sheet and method for producing recycled raw material

Abstract

The present disclosure provides a method for processing a resin sheet that has a base material and a resin coating film. The processing method comprises a separation step for separating the resin coating film from the base material using a cleaning solution. The cleaning solution contains an alcohol as the main component, and the 14C biomass degree of the cleaning solution is 88-100%.

Description

Method for treating resin sheets and method for producing recycled raw materials

[0001] The present disclosure relates to a method for treating a resin sheet and a method for producing recycled raw materials.

[0002] One approach to environmental issues is to reuse resources. For example, Patent Document 1 discloses a method for manufacturing a laminated ... ２ and a polyolefin resin layer in this order, in a release liquid to separate the polyolefin resin from the laminate; and a recovery step to recover the separated polyolefin resin.

[0003] Patent No. 7306552

[0004] A method for treating a resin sheet having a substrate and a resin coating film that places less of a burden on the environment is desired. The present disclosure has been made in view of the above-described circumstances, and a main object of the present disclosure is to provide a method for treating a resin sheet that can reduce the burden on the environment.

[0005] The present disclosure provides a method for treating a resin sheet having a substrate and a resin coating film, the method comprising a separation step of separating the resin coating film from the substrate using a cleaning liquid, the cleaning liquid containing alcohol as a main component, and １４ C. The biomass degree is 88% or more and 100% or less.

[0006] The present disclosure provides a method for producing recycled raw materials, which includes a recovery step of recovering the base material from the resin sheet using the above-described method for treating the resin sheet.

[0007] The present disclosure has an effect of providing a method for treating a resin sheet that can reduce environmental impact.

[0008] FIG. 1 is a flow diagram illustrating a method for treating a resin sheet according to the present disclosure. FIG. 2 is a schematic cross-sectional view illustrating a resin sheet according to the present disclosure. FIG. 3 is a schematic cross-sectional view illustrating a resin sheet according to the present disclosure. FIG. 4 is a schematic cross-sectional view illustrating a resin sheet according to the present disclosure. FIG. 5 is a schematic cross-sectional view illustrating a resin sheet according to the present disclosure. FIG. 6 is a schematic cross-sectional view illustrating a resin sheet according to the present disclosure. FIG. 7 is a schematic plan view illustrating a fractured piece according to the present disclosure.

[0009] Below, embodiments will be described with reference to the drawings. However, the present disclosure can be implemented in many different forms and is not limited to the description of the embodiments exemplified below. Furthermore, to clarify the description, the drawings may show the width, thickness, and shape of each part schematically compared to the actual form, but this is merely an example and should not be interpreted as limiting.

[0010] In this specification, when describing a mode in which another component is placed on a certain component, the term "above" or "below" is used, unless otherwise specified, to include both a case in which another component is placed directly above or below the certain component so as to be in contact with the component, and a case in which another component is placed above or below the certain component with another component interposed therebetween. Also, in this specification, when describing a mode in which another component is placed on the surface of a certain component, the term "on the surface" or "on the surface side" is used, unless otherwise specified, to include both a case in which another component is placed directly above or below the certain component so as to be in contact with the component, and a case in which another component is placed above or below the certain component with another component interposed therebetween.

[0011] Hereinafter, the method for treating a resin sheet and the method for producing recycled raw materials according to the present disclosure will be described in detail.

[0012] A. Resin Sheet Treatment Method Fig. 1 is a flow diagram illustrating a resin sheet treatment method according to the present disclosure. As shown in Fig. 1, the resin sheet treatment method according to the present disclosure includes a separation step of separating a resin coating film from a substrate using a cleaning liquid. As shown in Fig. 2, a resin sheet 10 is formed by separating a substrate 1 and a resin coating film R in a thickness direction D. ＴIn the separation step, the resin coating film R is separated from the substrate 1 using a cleaning liquid. The cleaning liquid in the present disclosure contains alcohol as a main component. １４ C. The biomass degree is 88% or more and 100% or less.

[0013] According to the present disclosure, １４ By using a cleaning solution with a high C biomass content (a cleaning solution containing a large amount of biological materials), it is possible to treat a resin sheet with a low environmental impact. Furthermore, since the cleaning solution contains alcohol as a main component, the resin coating film can be easily separated from the substrate, and the substrate can be recovered with little residual resin coating. Conventionally, resin sheets having a substrate and a resin coating film are discarded as industrial waste after use without being recycled. When reusing a resin sheet as a resource, it is desirable to separate the resin coating film from the substrate so that recycling destinations are not limited.

[0014] When a cleaning solution is used to separate a resin coating from a substrate, for example, if the cleaning solution contains a large amount of petroleum-derived materials, the cleaning solution itself places a burden on the environment. Typically, the amount of cleaning solution used is significantly greater than the amount of resin sheet processed, so the cleaning solution itself has a significant impact on the environment. In contrast, in the present disclosure, the cleaning solution contains a large amount of biological (particularly plant-derived) materials, allowing the resin sheet to be processed with a low environmental burden.

[0015] 1. Separation Step The separation step in the present disclosure is a step of separating the resin coating film from the substrate using a cleaning solution. The cleaning solution contains alcohol as a main component. １４ The C biomass degree is 88% or more and 100% or less. Furthermore, the separation in the present disclosure includes both peeling and separating the resin coating film from the substrate, and dissolving and separating the resin coating film from the substrate.

[0016] (1) Cleaning Solution The cleaning solution in this disclosure １４ C. The biomass degree is 88% or more and 100% or less. １４The C biomass content, also known as the biobased content, is an index that indicates the proportion of carbon-containing materials contained in the cleaning solution that are derived from living organisms. Carbon contains multiple isotopes, １２ C and １３ C is a stable isotope and accounts for the majority of carbon. １４ C is a radioisotope, １４ The carbon concentration is about 100 pMC (percent modern carbon). １４ The C concentration is maintained in equilibrium through life activities, but when life activities cease, １４ C undergoes beta decay １４ It changes to N, １４ The C concentration decreases over time (half-life: 5700 years). １４ The C concentration is about 100 pMC, but in petroleum-derived materials １４ The C concentration becomes zero.

[0017] For example, if 100% biological materials are used, the cleaning solution １４ On the other hand, if 100% petroleum-derived materials are used, the cleaning solution will have a biomass content of 100%. １４ In addition, if 50% of biologically derived materials and 50% of petroleum-derived materials are used (based on organic carbon), the cleaning solution will have a biomass content of 0%. １４ C The biomass ratio is 50%. １４ The biomass content is measured using AMS (Accelerator Mass Spectrometry) based on ASTM D6866 (bio-based content test standard). １４ The C biomass degree may be 90% or more, or 95% or more. １４ The C biomass degree may be 100% or less than 100%.

[0018] (i) Alcohol The cleaning solution in the present disclosure contains alcohol as a main component. The “main component” refers to the component with the largest mass among all components contained in the cleaning solution.

[0019] The cleaning solution according to the present disclosure contains a biologically-derived (particularly plant-derived) alcohol as the alcohol. The proportion of the biologically-derived alcohol in the total alcohol contained in the cleaning solution is, for example, 80% by mass or more, or may be 90% by mass or more, or may be 95% by mass or more. Meanwhile, the proportion may be 100% by mass or less than 100% by mass. The cleaning solution may contain only one type of biologically-derived alcohol, or two or more types.

[0020] The alcohol contained in the cleaning solution is not particularly limited. The number of carbon atoms of the alcohol is not particularly limited, but may be, for example, 1 or more, 5 or more, 7 or more, 10 or more, or 12 or more. When the number of carbon atoms of the alcohol is small, the boiling point of the alcohol tends to be low, and there is a possibility that the alcohol will volatilize from the cleaning solution. On the other hand, the number of carbon atoms of the alcohol is, for example, 25 or less, 20 or less, or 18 or less. When the number of carbon atoms of the alcohol is large, the viscosity of the cleaning solution tends to be high.

[0021] The number of hydroxyl groups contained in one molecule of alcohol is not particularly limited, and may be 1, 2, 3, or 4 or more. The molecular weight of the alcohol is also not particularly limited, and may be, for example, 32 to 250, or 90 to 220. The cleaning solution may contain only one type of alcohol, or two or more types of alcohol.

[0022] The boiling point of the alcohol contained in the cleaning solution is not particularly limited, and may be, for example, 60°C or higher, 80°C or higher, 100°C or higher, 120°C or higher, or 140°C or higher. On the other hand, the boiling point of the alcohol contained in the cleaning solution may be, for example, 380°C or lower, 360°C or lower, 340°C or lower, or 320°C or lower. The boiling point refers to the temperature at which the saturated vapor pressure of the liquid and the external pressure become equal, and corresponds to the temperature at which the liquid boils. In particular, it is preferable that the cleaning solution contains, as a main component, an alcohol having a boiling point of 120°C or higher.

[0023] The proportion of alcohol contained in the cleaning solution is, for example, 50% by mass or more, or may be 70% by mass or more, 80% by mass or more, 85% by mass or more, or 90% by mass or more. If the proportion of alcohol is too low, the resin coating film may not be able to be satisfactorily separated from the substrate. On the other hand, the proportion of alcohol contained in the cleaning solution may be 100% by mass or less than 100% by mass.

[0024] An example of the alcohol contained in the cleaning solution is an alcohol having a five-membered ring structure or a six-membered ring structure (hereinafter, may be referred to as alcohol A). The five-membered ring structure or the six-membered ring structure may have a monocyclic structure or a heterocyclic structure. The monocyclic structure is preferably a carbon monocyclic structure. The heterocyclic structure is preferably a heterocyclic structure having carbon and a heteroelement other than carbon. Examples of heteroelements other than carbon include oxygen, nitrogen, and sulfur. The five-membered ring structure or the six-membered ring structure may be a conjugated ring structure or a non-conjugated ring structure. The number of carbon atoms in alcohol A is not particularly limited, but may be, for example, 4 or more and 11 or less.

[0025] The boiling point of alcohol A is, for example, 60° C. or higher, and may be 80° C. or higher, 100° C. or higher, 120° C. or higher, 140° C. or higher, or 160° C. or higher. On the other hand, the boiling point of alcohol A is, for example, 300° C. or lower, 280° C. or lower, 260° C. or lower, or 240° C. The cleaning liquid may contain, as a main component, alcohol A having a boiling point within the above range.

[0026] Examples of alcohol A include benzyl alcohol, salicylic alcohol, benzenedimethanol, 4-(methoxymethyl)benzenemethanol, 3,4,5-trimethoxyphenylmethanol, phenethyl alcohol, cyclopentanol, cyclopentenol, cyclohexanol, methylcyclohexanol, 2-cyclohexen-1-ol, 1,4-cyclohexanediol, furfuryl alcohol, tetrahydrofurfuryl alcohol, tetrahydropyranmethanol, 4-morpholineethanol, 2-pyridinemethanol, 5-methyl-2-furanmethanol, and hydroxymethyl-γ-butyrolactone.

[0027] The alcohol A is preferably derived from a living organism (particularly from a plant). The cleaning solution may contain only one type of alcohol A, or two or more types. The proportion of alcohol A contained in the cleaning solution is not particularly limited, and may be, for example, 5% by mass or more, 10% by mass or more, 30% by mass or more, 50% by mass or more, or 70% by mass or more. Meanwhile, the proportion of alcohol A contained in the cleaning solution may be 100% by mass or less than 100% by mass.

[0028] Another example of the alcohol contained in the cleaning solution is an alcohol having 12 to 18 carbon atoms (hereinafter, may be referred to as alcohol B). Alcohol B may be a chain compound or a cyclic compound. The chain compound may have a linear structure or a branched chain structure. Alcohol B may have a 5-membered ring structure or a 6-membered ring structure, or may not have a 5-membered ring structure or a 6-membered ring structure. The 5-membered ring structure or the 6-membered ring structure is as described above.

[0029] The boiling point of alcohol B is, for example, 100°C or higher, and may be 120°C or higher, 140°C or higher, 160°C or higher, 180°C or higher, or 200°C or higher. On the other hand, the boiling point of alcohol B is, for example, 380°C or lower, 360°C or lower, 340°C or lower, or 320°C or lower. The boiling point of alcohol B may be higher than the boiling point of alcohol A. The cleaning liquid may contain alcohol B, whose boiling point is in the above range, as a main component.

[0030] Examples of alcohol B include 1-dodecanol, 1-tetradecanol, 1-hexadecanol, 1-octadecanol, 2-butyl-1-octanol, 2-pentyl-1-nonanol, 2-hexyl-1-decanol, 14-methyl-1-pentadecanol, 2-pentyl-1-dodecanol, 4-pentylcyclohexylmethanol, 3-(4-isopropylcyclohexyl)propanol, santalol, and 2-methyl-4-(2,2,3-trimethyl-3-cyclopenten-1-yl)-2-buten-1-ol.

[0031] The alcohol B is preferably derived from a living organism (particularly from a plant). The cleaning solution may contain only one type of alcohol B, or may contain two or more types. The proportion of the alcohol B contained in the cleaning solution is not particularly limited, and may be, for example, 5% by mass or more, 10% by mass or more, 30% by mass or more, 50% by mass or more, or 70% by mass or more. On the other hand, the proportion of the alcohol B contained in the cleaning solution may be 100% by mass or less than 100% by mass.

[0032] The cleaning solution of the present disclosure may contain both alcohol A and alcohol B. In this case, alcohol A and alcohol B are usually different compounds. The proportion of alcohol A relative to the total of alcohol A and alcohol B is not particularly limited, and may be, for example, 5% by mass or more, 10% by mass or more, 20% by mass or more, or 40% by mass or more. On the other hand, the proportion of alcohol A may be, for example, 95% by mass or less, 90% by mass or less, 80% by mass or less, or 60% by mass or less. Furthermore, the total proportion of alcohol A and alcohol B in the cleaning solution may be, for example, 50% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. On the other hand, the total proportion of alcohol A and alcohol B in the cleaning solution may be 100% by mass or less.

[0033] (ii) Other Components The cleaning solution according to the present disclosure may or may not contain water in addition to alcohol. The proportion of water contained in the cleaning solution is, for example, 40% by mass or less, or may be 30% by mass or less, or may be 15% by mass or less.

[0034] The cleaning solution of the present disclosure may or may not contain a nonionic surfactant in addition to alcohol. The use of a nonionic surfactant improves the separability of the resin coating film. The nonionic surfactant is preferably derived from a biological source (particularly a plant source).

[0035] An example of a nonionic surfactant is alkyl glucoxide. Alkyl glycosides are compounds in which sugars and higher alcohols are glycosidicly bonded. Examples of alkyl glycosides include decyl glucoside, lauryl glucoside, caprylyl glucoside, myristyl glucoside, undecyl glucoside, coconut oil alkyl glucoside, cetearyl glucoside, and isostearyl glucoside.

[0036] Other examples of nonionic surfactants include polyoxyalkylene alkyl ethers. Polyoxyalkylene alkyl ethers include, for example, CH ３ -(CH ２ ) ｍ -O-(C ２ H ４ O) ｎ It is preferable that the polyoxyalkylene alkyl ether has a composition represented by —H, where m is 11 or more and 15 or less, and n is 2 or more and 17 or less. Examples of polyoxyalkylene alkyl ethers include polyoxyethylene lauryl ether, polyoxyethylene myristyl ether, polyoxyethylene cetyl ether, and polyoxyalkylene lauryl ether.

[0037] The proportion of nonionic surfactants contained in the cleaning solution is, for example, 5% by mass or less, or may be 3% by mass or less, or may be 1% by mass or less. If the proportion of nonionic surfactants is too high, processing costs may increase. Furthermore, the cleaning solution of the present disclosure preferably does not contain inorganic metal salts such as sodium hydroxide. Furthermore, the cleaning solution of the present disclosure preferably does not contain petroleum-derived organic solvents.

[0038] (iii) Cleaning Liquid The boiling point of the cleaning liquid is not particularly limited, but may be, for example, 60° C. or higher, 80° C. or higher, 100° C. or higher, 120° C. or higher, or 140° C. or higher. On the other hand, the boiling point of the alcohol contained in the cleaning liquid may be, for example, 380° C. or lower, 360° C. or lower, 340° C. or lower, or 320° C. or lower.

[0039] (2) Resin Sheet The resin sheet in the present disclosure has a substrate and a resin coating film. As shown in FIG. 2, the resin sheet 10 has at least a substrate 1 and a resin coating film R. The substrate 1 and the resin coating film R are arranged in a thickness direction D. Ｔ are stacked along the

[0040] (i) Substrate The substrate is preferably a resin film. The resin used for the resin film is not particularly limited, but examples thereof include polyester, polyamide, polyolefin, vinyl resin, vinyl acetal resin, (meth)acrylic resin, imide resin, cellulose resin, styrene resin, polycarbonate, and ionomer.

[0041] Examples of the polyester include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylene dimethylene terephthalate, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer. Examples of the polyamide include nylon 6 and nylon 6,6. Examples of the polyolefin include polyethylene (PE), polypropylene (PP), and polymethylpentene. Examples of the vinyl resin include polyvinyl chloride, polyvinyl alcohol (PVA), polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, and polyvinylpyrrolidone (PVP).

[0042] Examples of the vinyl acetal resin include polyvinyl acetoacetal and polyvinyl butyral. Examples of the (meth)acrylic resin include poly(meth)acrylate. "(Meth)acrylic" includes both "acrylic" and "methacrylic", and "(meth)acrylate" includes both "acrylate" and "methacrylate". Examples of the imide resin include polyimide and polyetherimide. Examples of the cellulose resin include cellophane, cellulose acetate, nitrocellulose, cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB). Examples of the styrene resin include polystyrene (PS).

[0043] The substrate may be a laminate of resin films. The resin film may be a stretched film or an unstretched film. The thickness of the substrate varies depending on the type of resin sheet and is not particularly limited, but is, for example, 2.0 μm or more and 100 μm or less. The thickness of the substrate may be 2.0 μm or more and 10 μm or less, 2.5 μm or more and 8.0 μm or less, or 3.0 μm or more and 6.0 μm or less. The above range is a suitable range when the resin sheet has a relatively thin substrate. A specific example of a resin sheet having a relatively thin substrate is a thermal transfer sheet, which will be described later. On the other hand, the thickness of the substrate may be 30 μm or more and 100 μm or less, or 40 μm or more and 90 μm or less. The above range is a suitable range when the resin sheet has a relatively thick substrate.

[0044] (ii) Resin Coating Film: The resin coating film is a coating film containing a resin. The resin coating film may contain a thermoplastic resin or a cured product (crosslinked product) of a curable resin. The resin coating film may be a crosslinked resin coating film in which a diisocyanate compound is detected by pyrolysis GC / MS. The resin used in the resin coating film may be the resin described for each layer below. The resin sheet may have only one resin coating film, or may have two or more resin coating films. The resin coating film may be disposed on only one side of the substrate, or on both sides of the substrate. The coverage of the resin coating film with respect to the substrate is not particularly limited, but is preferably, for example, 80% or more and 100% or less. The resin coating film varies depending on the type of resin sheet. A typical example of a resin sheet having a resin coating film is described below using a thermal transfer sheet.

[0045] (a) Thermal Transfer Sheet FIG. 3 is a schematic cross-sectional view illustrating a resin sheet according to the present disclosure, specifically illustrating a resin sheet that is a thermal transfer sheet. As shown in FIG. 3(a), the resin sheet 10 that is a thermal transfer sheet may have a substrate 1 and a colorant layer 2. The colorant layer 2 in FIG. 3(a) corresponds to a resin coating film. As shown in FIG. 3(b), the resin sheet 10 that is a thermal transfer sheet may have a release layer 3 between the substrate 1 and the colorant layer 2. The colorant layer 2 and release layer 3 in FIG. 3(b) correspond to a resin coating film. As shown in FIG. 3(c), the resin sheet 10 that is a thermal transfer sheet may have a primer layer 4 between the substrate 1 and the colorant layer 2. The colorant layer 2 and primer layer 4 in FIG. 3(c) correspond to a resin coating film. As shown in FIG. 3(d), the resin sheet 10 that is a thermal transfer sheet may have a substrate 1 and a protective layer 5. The protective layer 5 in FIG. 3(d) corresponds to a resin coating film.

[0046] (a-1) Colorant Layer As shown in FIG. 3(a), the resin sheet 10, which is a thermal transfer sheet, may have a colorant layer 2. The colorant layer 2 contains a colorant and a binder. Examples of the hue of the colorant include magenta, yellow, cyan, and black.

[0047] The coloring material may be a pigment or a dye. Examples of the coloring material include carbon black, acetylene black, lamp black, black smoke, iron black, aniline black, silica, calcium carbonate, titanium oxide, cadmium red, cadmium phosphate red, chrome red, vermilion, red iron oxide, azo pigments, alizarin lake, quinacridone, cochineal lake perylene, yellow ochre, aureolin, cadmium yellow, cadmium orange, chrome yellow, zinc yellow, Naples yellow, nickel yellow, greenish yellow, ultramarine, rock ultramarine, cobalt, phthalocyanine, anthraquinone, indicoid, cinnabar green, cadmium green, chrome green, phthalocyanine, azomethine, perylene, and aluminum pigments.

[0048] The colorant may be a sublimable dye, such as a diarylmethane dye, a triarylmethane dye, a thiazole dye, a merocyanine dye, a pyrazolone dye, a methine dye, an indoaniline dye, an acetophenone azomethine dye, a pyrazoloazomethine dye, a xanthene dye, an oxazine dye, a thiazine dye, an azine dye, an acridine dye, an azo dye, a spiropyran dye, an indolinospiropyran dye, a fluoran dye, a naphthoquinone dye, an anthraquinone dye, or a quinophthalone dye.

[0049] The content of the colorant in the colorant layer is not particularly limited, but may be, for example, 5% by mass or more and 75% by mass or less, or 10% by mass or more and 50% by mass or less.

[0050] The colorant layer may be a melt-transfer type colorant layer in which a colorant such as a pigment or dye is dispersed in a heat-melting binder, or a sublimation transfer type colorant layer in which a sublimation dye is dissolved or dispersed in a binder. Examples of the binder include resins. Examples of resins include polyester, polyurethane, polyamide, polyimide, polycarbonate, polyolefin, (meth)acrylic resin, vinyl resin, styrene resin, cellulose resin, phenoxy resin, epoxy resin, and ionomer.

[0051] The melt-transfer colorant layer may contain a wax as a binder, such as microcrystalline wax, carnauba wax, paraffin wax, Fischer-Tropsch wax, polyethylene wax, Japan wax, beeswax, whale wax, Ibota wax, wool wax, shellac wax, candelilla wax, petrolactam, polyester wax, partially modified wax, fatty acid ester, and fatty acid amide.

[0052] The melt-transfer colorant layer may contain a cured (crosslinked) binder. Examples of curing agents for curing the binder include isocyanates and carbodiimides. The melt-transfer colorant layer may contain, as a binder, a cured (crosslinked) binder of at least one of an actinic radiation-curable monomer and an actinic radiation-curable oligomer. The actinic radiation-curable monomer and actinic radiation-curable oligomer refer to monomers and oligomers that polymerize (cure) when irradiated with actinic radiation. "Actinic radiation" refers to radiation that chemically reacts with the actinic radiation-curable monomer and actinic radiation-curable oligomer to promote polymerization. Examples of actinic radiation include visible light, ultraviolet light, X-rays, electron beams, α-rays, β-rays, and γ-rays.

[0053] Examples of actinic radiation-curable monomers include urethane acrylate, epoxy acrylate, polyester acrylate, polyether acrylate, polyethylene acrylate, silicone acrylate, and polyol acrylate. The number of functional groups in the actinic radiation-curable monomer is not particularly limited, but may be, for example, 2 or more, or may be 3 or more. On the other hand, examples of actinic radiation-curable oligomers include polymers or copolymers of the actinic radiation-curable monomers. The number of functional groups in the actinic radiation-curable oligomer is not particularly limited, but may be, for example, 2 or more, or may be 3 or more.

[0054] The thickness of the color material layer is not particularly limited, but may be, for example, 0.3 μm or more and 7 μm or less, or 1 μm or more and 6 μm or less.

[0055] (a-2) Release Layer As shown in FIG. 3(b), the resin sheet 10, which is a thermal transfer sheet, may have a release layer 3 between the substrate 1 and the colorant layer 2. The provision of the release layer 3 can improve transferability. The release layer 3 preferably contains a resin. Examples of such resins include (meth)acrylic resin, vinyl resin, styrene resin, cellulose resin, polyester, polyurethane, polyamide, polyimide, and polycarbonate. The release layer 3 may contain a cured (crosslinked) resin. Examples of curing agents for curing resins include isocyanate and carbodiimide. The release layer 3 may contain, as a resin, a cured (crosslinked) resin of at least one of an actinic radiation-curable monomer and an actinic radiation-curable oligomer. The release layer 3 may also contain additives such as a lubricant, an ultraviolet absorber, a light stabilizer, and an antioxidant.

[0056] (a-3) Primer Layer As shown in FIG. 3(c), the resin sheet 10, which is a thermal transfer sheet, may have a primer layer 4 between the substrate 1 and the colorant layer 2. By providing the primer layer 4, it is possible to improve the adhesion between the substrate 1 and the colorant layer 2. The primer layer 4 preferably contains a resin. Examples of the resin include polyester, vinyl resin, (meth)acrylic resin, styrene resin, polyamide, polyether, urethane resin, and cellulose resin.

[0057] (a-4) Protective Layer As shown in FIG. 3(d), the resin sheet 10, which is a thermal transfer sheet, may have a protective layer (OP layer) 5. The protective layer 5 is a transparent layer containing a resin. The resin used for the protective layer 5 is not particularly limited, but examples thereof include polyester, polystyrene, polyurethane, (meth)acrylic resin, (meth)acrylic urethane resin, and vinyl chloride-vinyl acetate copolymer. The resin may be, for example, a silicone-modified resin. Furthermore, the protective layer 5 may contain a coloring material such as a fluorescent whitening agent, or may not contain a coloring material.

[0058] (a-5) Specific Example of Thermal Transfer Sheet Figure 4 is a schematic cross-sectional view illustrating a resin sheet (thermal transfer sheet) in the present disclosure, specifically showing a melt-transfer type thermal transfer sheet. The release layer 3 shown in Figure 4 is usually transferred to the transfer recipient side as part of the transfer layer α during thermal transfer. The resin sheet 10 is oriented in the thickness direction D Ｔ In the resin sheet 10, a back layer 6 may be provided on the opposite side of the color material layer 2 with respect to the substrate 1. By providing the back layer 6, it is possible to suppress the occurrence of sticking caused by a thermal head. Ｔ In the above, an adhesive layer 7 may be provided on the side opposite to the substrate 1 with respect to the colorant layer 2. By providing the adhesive layer 7, it is possible to improve adhesion to the transfer target. Known configurations can be adopted for the release layer 3, back layer 6, and adhesive layer 7.

[0059] 5 is a schematic cross-sectional view illustrating a resin sheet (thermal transfer sheet) according to the present disclosure, specifically illustrating a sublimation transfer type thermal transfer sheet. The primer layer 4 shown in FIG. 5 improves the adhesion between the substrate 1 and the color material layer 2. The resin sheet 10 is formed in a thickness direction D. Ｔ In the resin sheet 10, a back surface layer 6 may be provided on the opposite side of the color material layer 2 with respect to the substrate 1. Ｔ In the above, a second primer layer 8 may be provided between the substrate 1 and the back surface layer 6. By providing the second primer layer 8, the adhesion between the substrate 1 and the back surface layer 6 is improved. Known configurations can be adopted for the primer layer 4, the back surface layer 6, and the second primer layer 8.

[0060] FIG. 6 is a schematic cross-sectional view illustrating a resin sheet (thermal transfer sheet) according to the present disclosure, specifically showing a thermal transfer sheet having a protective layer (OP layer). The primer layer 4 shown in FIG. 6 improves the adhesion between the protective layer 5 and the adhesive layer 7. The adhesive layer 7 according to the present disclosure may be a heat seal layer. The resin sheet 10 is also formed in a thickness direction D. Ｔ In the resin sheet 10, a back surface layer 6 may be provided on the opposite side of the color material layer 2 with respect to the substrate 1. ＴIn the above, a second primer layer 8 may be provided between the substrate 1 and the back surface layer 6. The primer layer 4, the back surface layer 6, and the second primer layer 8 may have a known configuration.

[0061] (b) Resin Sheets Other Than Thermal Transfer Sheets The resin sheet in the present disclosure is not limited to a thermal transfer sheet, and any sheet having a substrate and a resin coating can be used. The resin coating may be colored or uncolored. FIG. 7 is a schematic cross-sectional view illustrating an example of a resin sheet in the present disclosure. As shown in FIG. 7, the resin sheet may have a substrate 1 and a printing layer 9. The printing layer 9 contains, for example, a colorant (colorant) and a binder. The colorant and binder are the same as those described above.

[0062] (iii) Resin Sheet The resin sheet has the above-described substrate and resin coating film. The thickness of the resin sheet varies depending on the type of resin sheet and is not particularly limited, but may be, for example, 3.0 μm or more and 150 μm or less, or 3.0 μm or more and 100 μm or less. The thickness of the resin sheet may be 3.0 μm or more and 12 μm or less, 3.5 μm or more and 10 μm or less, or 4.0 μm or more and 8.0 μm or less. The above range is a suitable range when the resin sheet has a relatively thin substrate. On the other hand, the thickness of the resin sheet may be 30 μm or more and 150 μm or less, 35 μm or more and 120 μm or less, or 45 μm or more and 110 μm or less. The above range is a suitable range when the resin sheet has a relatively thick substrate.

[0063] In the separation step, the resin sheet is washed using a cleaning liquid to separate the resin coating film from the substrate. The resin sheet in the washing step may be in the form of crushed pieces 11, as shown in FIG. 8 . That is, a crushing step in which the resin sheet is crushed to produce crushed pieces may be performed before or simultaneously with the separation step. The crushed pieces are brought into contact with the cleaning liquid to separate the resin coating film from the substrate. By using the crushed pieces, a large amount of resin sheet can be washed. On the other hand, in the case of a thin resin sheet with little stiffness, such as a thermal transfer sheet, the crushed pieces tend to aggregate, and the cleaning liquid does not easily penetrate into areas where multiple crushed pieces aggregate, making it difficult to separate the resin coating film from the substrate. In contrast, in the present disclosure, by using the above-mentioned cleaning liquid, the cleaning liquid can penetrate into areas where multiple crushed pieces aggregate, and the resin coating film can be successfully separated from the substrate. The area of ​​the crushed pieces is, for example, 1 cm ２ More than 15cm ２ less than or equal to 1.5 cm ２ Above, 10cm ２ The area of ​​the crushed pieces is calculated as the average area of ​​a plurality of crushed pieces. On the other hand, the resin sheet in the cleaning treatment does not have to be crushed pieces.

[0064] When preparing crushed pieces, the size and shape of the crushed pieces are not particularly limited, but it is preferable that they are in an appropriate state so that the contact area between the cleaning solution and the object to be cleaned is increased. Examples of crushing devices for crushing the resin sheet include jaw crushers, impact crushers, cutter mills, stamp mills, ring mills, roller mills, jet mills, and hammer mills. The crushing conditions for the resin sheet are not particularly limited.

[0065] (3) Separation step The separation step is a step of separating the resin coating film from the substrate using a cleaning liquid. In the separation step, the mass (amount used) of the cleaning liquid relative to the mass (amount treated) of the resin sheet is, for example, 10 times or more, 20 times or more, 40 times or more, 100 times or more, 150 times or more, or 200 times or more. If the mass (amount used) of the cleaning liquid is too small, the resin coating film may not be separated well from the substrate. On the other hand, the mass (amount used) of the cleaning liquid relative to the mass (amount treated) of the resin sheet may be, for example, 600 times or less, 550 times or less, or 500 times or less. If the mass (amount used) of the cleaning liquid is too large, a large amount of cleaning liquid is required, which may reduce the processing efficiency.

[0066] The method for cleaning the resin sheet with the cleaning liquid is not particularly limited, but for example, a method of immersing the resin sheet in the cleaning liquid can be mentioned. The temperature of the cleaning liquid during immersion is not particularly limited, but may be, for example, 25° C. or higher and 100° C. or lower, or 30° C. or higher and 80° C. or lower. The immersion time is, for example, 1 minute or longer and 24 hours or shorter.

[0067] In the separation step, it is preferable to stir the cleaning solution in which the resin sheet is immersed. Stirring allows for better separation of the resin coating film from the substrate. When stirring the cleaning solution in which the resin sheet is immersed, media such as beads may be used, or no media may be used. In the former case, the media dispersed in the cleaning solution come into contact with the resin sheet, allowing for better separation of the resin coating film from the substrate. On the other hand, in the latter case, the generation of bubbles can be suppressed compared to the former. In addition, the cleaning agent may or may not contain additives such as activated carbon, anti-redeposition agents, and antifoaming agents. The separation step may be performed once or twice or more times. Examples of devices for separating the resin sheet include a mechanical mixer, a Henschel mixer, a tumbler mixer, and an ultrasonic device.

[0068] 2. Rinsing Step The resin sheet treatment method according to the present disclosure preferably includes a rinsing step for removing the cleaning liquid remaining on the substrate after the separation step. The rinsing step can also promote separation of the resin coating film and the substrate.

[0069] In the rinsing step, a rinse liquid is usually used to remove the cleaning liquid remaining on the substrate. An example of the rinse liquid is water. Among them, warm water is preferable as the rinse liquid. This is because the cleaning liquid remaining on the substrate can be efficiently removed. The temperature of the warm water is, for example, 35°C or higher and 60°C or lower. On the other hand, the rinse liquid may be an organic solvent. The rinse liquid may contain only one organic solvent, or may contain two or more organic solvents. In addition, the organic solvent is preferably derived from a living organism (particularly from a plant). The rinse liquid １４ The C biomass degree is preferably 88% or more and 100% or less. The boiling point of the organic solvent is, for example, less than 100°C, and may be 95°C or less, 90°C or less, or 85°C or less. On the other hand, the boiling point of the organic solvent is, for example, 40°C or more, and may be 50°C or more. Examples of organic solvents include alcohols such as ethanol and isopropyl alcohol, ketones such as acetone, and ethers such as tetrahydrofuran.

[0070] The rinse liquid may be water (including warm water), an organic solvent, or a mixture of water and an organic solvent. Here, a rinse liquid containing water as a main component is referred to as rinse liquid A. The proportion of water in rinse liquid A may be, for example, 50% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more. Meanwhile, the proportion of water in rinse liquid A may be 100% by mass or less. The boiling point of rinse liquid A may be, for example, 80°C or more and 120°C or less, or 90°C or more and 110°C or less.

[0071] A rinse liquid containing an organic solvent as a main component is referred to as rinse liquid B. The proportion of the organic solvent in rinse liquid B is, for example, 50% by mass or more, or may be 70% by mass or more, 80% by mass or more, or 90% by mass or more. On the other hand, the proportion of the organic solvent in rinse liquid B may be 100% by mass or less. The boiling point of rinse liquid B may be, for example, 40°C or more and less than 100°C, or 50°C or more and 85°C or less. The boiling point of rinse liquid B is preferably lower than the boiling point of rinse liquid A. The difference between the boiling points of rinse liquid A and rinse liquid B is, for example, 10°C or more, or may be 15°C or more, or may be 20°C or more. On the other hand, the difference between the boiling points of rinse liquid A and rinse liquid B is, for example, 60°C or less.

[0072] In the rinsing step, a removal treatment using a rinse liquid to remove the cleaning liquid remaining on the substrate may be performed once or twice or more times. When the removal treatment is performed twice or more times, the same rinse liquid may be used in each removal treatment, or different rinse liquids may be used. When the rinse liquid used in the nth (n is an integer of 1 or more) removal treatment is rinse liquid X and the rinse liquid used in the n+1th removal treatment is rinse liquid Y, it is preferable that the rinse liquid Y has a lower boiling point than the rinse liquid X. This is because the drying temperature in the subsequent drying step can be reduced. For example, when the rinse liquid X is water, it is preferable that the rinse liquid Y has a lower boiling point than water, i.e., a boiling point of less than 100°C. Examples of liquids with a boiling point lower than water include ethanol (boiling point 78.4°C) and isopropyl alcohol (boiling point 82.3°C). The liquid with a boiling point lower than water may also be the organic solvent described above.

[0073] The rinse liquid X may be the rinse liquid A described above, and the rinse liquid Y may be the rinse liquid B described above. That is, the rinsing process preferably includes a first rinsing process in which the rinse liquid A is used to remove the cleaning liquid remaining on the substrate, and a second rinsing process in which the rinse liquid B, which has a boiling point lower than that of the rinse liquid A, is used to remove the cleaning liquid remaining on the substrate after the first rinsing process. In particular, the boiling point of the rinse liquid B is preferably less than 100°C. If the boiling point of the rinse liquid B is too high, the drying residue is likely to remain, which may result in problems in subsequent processes such as molding. On the other hand, if the boiling point of the rinse liquid B is too low, the evaporation of the rinse liquid B may reduce production stability. In addition, examples of equipment used in the rinsing process include a mechanical mixer, a Henschel mixer, a tumbler mixer, and an ultrasonic device.

[0074] 3. Drying Step The resin sheet treatment method according to the present disclosure may include a drying step of drying the substrate separated from the resin coating film after the separation step. In addition, when the resin sheet treatment method includes the above-described rinsing step, the resin sheet treatment method may include a drying step after the rinsing step.

[0075] The drying temperature in the drying step is not particularly limited, and may be, for example, 80°C or higher, 90°C or higher, 100°C or higher, or 120°C or higher. On the other hand, the drying temperature in the drying step may be, for example, 160°C or lower, 150°C or lower, 140°C or lower, 120°C or lower, or 100°C or lower. If the drying temperature is too low, it may be difficult to sufficiently dry the substrate. On the other hand, if the drying temperature is too high, the processing efficiency may decrease. Furthermore, if the drying temperature is too low, the drying property may decrease, and if the drying temperature is too high, the dried material may be thermally damaged.

[0076] The drying time in the drying step is not particularly limited, but may be, for example, 30 minutes or more, 1 hour or more, or 2 hours or more. On the other hand, the drying time in the drying step may be, for example, 12 hours or less, 10 hours or less, 8 hours or less, or 5 hours or less. If the drying time is too short, it may be difficult to sufficiently dry the substrate. On the other hand, if the drying time is too long, the processing efficiency may decrease. Furthermore, if the drying time is too short, the drying property may be insufficient, and if the drying time is too long, the working efficiency may decrease.

[0077] The drying method in the drying step is not particularly limited, but examples thereof include reduced pressure heating drying, hot air drying, and pressurized compression drying. The above drying methods can be used alone or in combination.

[0078] B. Manufacturing Method of Recycled Raw Materials The manufacturing method of recycled raw materials in the present disclosure includes a recovery step of recovering the base material from the resin sheet using the treatment method described above in "A. Treatment method of resin sheet."

[0079] According to the present disclosure, by treating a resin sheet using the above-mentioned treatment method, recycled raw materials can be obtained while reducing the environmental load. The recovery process is the same as that described above in "A. Treatment method for resin sheet," and therefore will not be described here.

[0080] The method for producing recycled materials may include a pelletizing step of pelletizing the recovered substrate, as needed, to obtain recycled materials in the form of pellets.

[0081] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included within the technical scope of the present disclosure.

[0082] [Preparation of cleaning solution] Plant-derived tetrahydrofurfuryl alcohol (boiling point: 178°C), plant-derived 1-dodecanol (boiling point: 261°C), and water were mixed in a mass ratio of tetrahydrofurfuryl alcohol:1-dodecanol:water = 80.6:10.1:9.3 to obtain cleaning solution 1. Furthermore, the materials shown in Table 1 were mixed in the compositions shown in Table 1 to obtain cleaning solutions 2 to 4. In cleaning solutions 2 to 4, all of the materials containing carbon elements were plant-derived materials. Therefore, cleaning solutions 1 to 4 １４ The C biomass degree was 100% in all cases. Note that lauryl glucoxide and polyoxyethylene lauryl ether in Table 1 do not have boiling points.

[0083] On the other hand, water, sodium hydroxide, and plant-derived polyoxyalkylene lauryl ether were mixed in a mass ratio of water:sodium hydroxide:polyoxyalkylene lauryl ether = 97.7:2:0.3 to obtain cleaning solution 5. Furthermore, petroleum-derived toluene and petroleum-derived methyl ethyl ketone were mixed in a mass ratio of toluene:methyl ethyl ketone = 50:50 to obtain cleaning solution 6. １４ The C biomass content is almost 0%, and the cleaning solution 6 １４ The C biomass ratio was 0%.

[0084]

[0085] [Preparation of Resin Sheet] Resin sheet 1 was prepared as a dye-sublimation thermal transfer sheet having a crosslinked resin coating (containing a diisocyanate compound as a crosslinking component, thickness 0.5 μm) on one side of a substrate (PET, thickness 6.5 μm) and a dye-containing resin coating (thickness 0.5 μm) on the other side. Resin sheet 2 was prepared as a sheet (thickness 100 μm) having a resin coating (printed layer, thickness 8.0 μm) formed by gravure printing on a substrate (polyethylene, thickness 92 μm). Resin sheet 3 was prepared as a sheet (thickness 80 μm) having a resin coating (printed layer, thickness 8.0 μm) formed by gravure printing on a substrate (polyethylene, thickness 72 μm). Resin sheet 4 was prepared as a melt-type thermal transfer sheet having a resin coating (0.2 μm thick) on one side of a substrate (PET, 12 μm thick) and a resin coating (7.5 μm thick) containing resin and carbon black on the other side. Resin sheet 5 was prepared as a melt-type thermal transfer sheet having a resin coating (0.2 μm thick) on one side of a substrate (PET, 6.0 μm thick) and a resin coating (1.2 μm thick) containing resin and carbon black on the other side. Resin sheets 1 to 5 are summarized in Table 2.

[0086]

[0087] [Example 1] Resin sheet 1 was shredded using a ribbon shredder (device name: GRASYS BiT) to obtain shredded pieces. The cutting method was twisted micro-cutting, and the maximum shredding speed was 12 m / min. Then, cleaning solution 1 was added to a container and heated in a hot water bath until the temperature of cleaning solution 1 reached 50°C. Next, 1.0 g of the shredded pieces was placed in a 100 mL beaker, and 49 g of heated cleaning solution 1 was added. The mixture was stirred at room temperature at 300 rpm for 10 minutes. After stirring, the shredded pieces were collected using a sieve with 2 mm openings.

[0088] The recovered fragments were then placed in 49 g of hot water at 50°C and stirred at room temperature at 300 rpm for 5 minutes (rinsing step). After stirring, the fragments (substrate) were recovered using a sieve with 2 mm openings, drained, and dried with hot air in an oven at 140°C for 3 hours (drying step). This yielded washed fragments (substrate).

[0089] Examples 2 to 4 Cleaned crushed pieces (substrates) were obtained in the same manner as in Example 1, except that cleaning solutions 2 to 4 were used instead of cleaning solution 1.

[0090] Examples 5 to 8 Washed crushed pieces (substrates) were obtained in the same manner as in Example 1, except that resin sheets 2 to 5 were used instead of resin sheet 1.

[0091] Example 9 The same procedure as in Example 1 was carried out except that the hot water used in the rinsing step was changed to water at 25°C, and thus washed crushed pieces (substrate) were obtained.

[0092] Example 10 Cleaned crushed pieces (substrates) were obtained in the same manner as in Example 1, except that the oven temperature in the drying step was changed to 100°C.

[0093] [Example 11] The same procedure as in Example 1 was followed up to the rinsing step (first rinsing treatment). Next, after stirring, the crushed pieces (substrate) were collected using a sieve with 2 mm openings. Next, the crushed pieces were placed in 49 g of ethanol (EtOH, boiling point 78.4 ° C) at 25 ° C and stirred at 300 rpm for 5 minutes under room temperature conditions (second rinsing treatment). Next, after stirring, the crushed pieces (substrate) were collected using a sieve with 2 mm openings and dried with hot air in an oven at 100 ° C for 3 hours (drying treatment). This resulted in the crushed pieces (substrate) after washing.

[0094] [Examples 12 to 17] Crushed pieces (substrates) after washing were obtained in the same manner as in Example 11, except that the type of resin sheet, whether or not a first rinse treatment was performed, and the type of rinse liquid in the second rinse treatment were changed as shown in Table 4. In Table 4, IPA is isopropanol (boiling point 82.3°C), ACE is acetone (boiling point 56°C), and THF is tetrahydrofuran (boiling point 66°C).

[0095] [Comparative Example 1] Cleaned crushed pieces (substrates) were obtained in the same manner as in Example 1, except that cleaning solution 5 was used instead of cleaning solution 1 and the drying temperature in the drying step was changed from 140°C to 110°C.

[0096] Comparative Example 2 A washed crushed piece (substrate) was obtained in the same manner as in Comparative Example 1, except that Resin Sheet 5 was used instead of Resin Sheet 1.

[0097] [Comparative Example 3] Cleaned crushed pieces (substrates) were obtained in the same manner as in Example 1, except that cleaning solution 6 was used instead of cleaning solution 1 and the drying temperature in the drying step was changed from 140°C to 120°C.

[0098] [Evaluation] (Residual rate of resin coating film) The surface of the crushed pieces before and after cleaning was photographed using a microscope (magnification 20x). These images were captured using a scanner (CanoScan9000F) under the following conditions: resolution: 600 dpi, color mode: grayscale, color correction: none. The captured images were binarized using image analysis software (ImageJ), and the number of dots from 0 to 200 gradations was counted. The residual rate of resin coating film was calculated using the following formula: Residual rate of resin coating film (%) = (number of dots after cleaning) / (number of dots before cleaning) x 100

[0099] The remaining rate of the resin coating film was evaluated according to the following criteria. The results are shown in Tables 3 and 4. AA: The remaining rate of the resin coating film was less than 2%. A: The remaining rate of the resin coating film was 2% or more and less than 5%. B: The remaining rate of the resin coating film was 5% or more and less than 10%. C: The remaining rate of the resin coating film was 10% or more.

[0100] (Residual Rate of Cleaning Solution) The fragments after the rinsing process were measured using GC-MS (JMS-Q1500GC model and JMS-T1000CV model manufactured by JEOL Ltd.). Of the detected components, the total amount of tetrahydrofurfuryl alcohol and 1-dodecanol detected was calculated, and the residual rate of the cleaning solution was calculated using the following formula: Residual rate of cleaning solution (%) = {(Detected amount of tetrahydrofurfuryl alcohol) + (Detected amount of 1-dodecanol)} / (Mass of fragments) × 100

[0101] The residual rate of the cleaning liquid was evaluated according to the following criteria. The results are shown in Tables 3 and 4. A: The residual rate of the cleaning liquid was less than 0.12%. B: The residual rate of the cleaning liquid was 0.12% or more. C: Not detected.

[0102]

[0103]

[0104] As shown in Tables 3 and 4, in Examples 1 to 17, the residual rate of the resin coating film was low, and the resin coating film was successfully separated from the substrate. In particular, in Examples 13 and 15, the first rinse was performed with warm water, and the second rinse was performed with IPA, which has a boiling point lower than that of water, which resulted in an extremely low residual rate of the resin coating film. １４ The use of cleaning solutions 1 to 4, each with a high C biomass content, enabled a reduction in the environmental impact. Furthermore, in Examples 1 to 17, the residual rate of the resin coating film was low, and the residual rate of the cleaning solution was also low. In contrast, in Comparative Examples 1 to 3, the residual rate of the resin coating film was high, and the resin coating film could not be satisfactorily separated from the substrate.

[0105] Thus, the present disclosure provides, for example, the following inventions.

[0106] [1] A method for treating a resin sheet having a substrate and a resin coating film, the method comprising: a separation step of separating the resin coating film from the substrate using a cleaning liquid; the cleaning liquid contains alcohol as a main component; １４ C. A method for treating a resin sheet, wherein the biomass degree is 88% or more and 100% or less.

[0107] [2] The method for treating a resin sheet according to [1], wherein the cleaning solution contains, as the alcohol, an alcohol A having a five-membered ring structure or a six-membered ring structure.

[0108] [3] The method for treating a resin sheet according to [2], wherein the alcohol A is tetrahydrofurfuryl alcohol.

[0109] [4] The method for treating a resin sheet according to any one of [1] to [3], wherein the cleaning solution contains, as the alcohol, an alcohol B having 12 to 18 carbon atoms.

[0110] [5] The method for treating a resin sheet according to [4], wherein the alcohol B is 1-dodecanol.

[0111] [6] The method for treating a resin sheet according to any one of [1] to [5], wherein the cleaning solution contains an alkyl glucoxide having an alkyl group with 8 to 16 carbon atoms.

[0112] [7] The cleaning solution is CH ３ -(CH ２ ) ｍ -O-(C ２ H ４ O) ｎ The method for treating a resin sheet according to any one of [1] to [6], containing a polyoxyalkylene alkyl ether represented by —H (m is 11 or more and 15 or less, and n is 2 or more and 17 or less).

[0113] [8] The method for treating a resin sheet according to any one of [1] to [7], wherein the boiling point of the cleaning liquid is 120°C or higher.

[0114] [9] The method for treating a resin sheet according to any one of [1] to [8], wherein the thickness of the resin sheet is 3.0 μm or more and 150 μm or less.

[0115]

[10] The method for treating a resin sheet according to any one of [1] to [9], wherein the resin sheet has a thickness of 3.0 μm or more and 12 μm or less.

[0116]

[11] The method for treating a resin sheet according to any one of [1] to

[10] , wherein the coverage of the resin coating film with respect to the substrate is 80% or more and 100% or less.

[0117]

[12] The method for treating a resin sheet according to any one of [1] to

[11] , wherein the resin coating film is a crosslinked resin coating film in which a diisocyanate compound is detected by a pyrolysis GC / MS method.

[0118]

[13] The method for treating a resin sheet according to any one of [1] to

[12] , further comprising: a rinsing step of removing the cleaning liquid remaining on the substrate after the separating step; and a drying step of drying the substrate after the rinsing step.

[0119]

[14] The method for treating a resin sheet according to

[13] , wherein in the rinsing step, the cleaning liquid remaining on the substrate is removed using a rinsing liquid A containing water as a main component.

[0120]

[15] The method for treating a resin sheet according to

[13] or

[14] , wherein in the rinsing step, the cleaning liquid remaining on the substrate is removed using a rinsing liquid B containing an organic solvent as a main component and having a boiling point of less than 100°C.

[0121]

[16] The method for treating a resin sheet according to

[13] , wherein the rinsing step includes: a first rinsing treatment in which a rinsing liquid A containing water as a main component is used to remove the cleaning liquid remaining on the substrate; and, after the first rinsing treatment, a second rinsing treatment in which a rinsing liquid B containing an organic solvent as a main component and having a boiling point lower than that of the rinsing liquid A is used to remove the cleaning liquid remaining on the substrate.

[0122]

[17] The method for treating a resin sheet according to any one of [1] to

[16] , further comprising a crushing step of crushing the resin sheet to produce crushed pieces before or simultaneously with the separation step.

[0123]

[18] A method for producing recycled raw materials, comprising a recovery step of recovering the base material from a resin sheet using the method for treating a resin sheet according to any one of [1] to

[17] .

[0124] DESCRIPTION OF SYMBOLS 1... Substrate 2... Colorant layer 3... Release layer 4... Primer layer 5... Protective layer 6... Back layer 7... Adhesive layer 8... Second primer layer 9... Printed layer 10... Resin sheet 11... Shattered pieces

Claims

1. A method for treating a resin sheet having a substrate and a resin coating film, the method comprising: a separation step of separating the resin coating film from the substrate using a cleaning liquid; the cleaning liquid containing alcohol as a main component; １４ C. A method for treating a resin sheet, wherein the biomass degree is 88% or more and 100% or less.

2. The method for treating a resin sheet according to claim 1, wherein the cleaning solution contains, as the alcohol, an alcohol A having a five-membered ring structure or a six-membered ring structure.

3. The method for treating a resin sheet according to claim 2, wherein the alcohol A is tetrahydrofurfuryl alcohol.

4. The method for treating a resin sheet according to claim 1, wherein the cleaning solution contains alcohol B having 12 or more and 18 or less carbon atoms as the alcohol.

5. The method for treating a resin sheet according to claim 4, wherein the alcohol B is 1-dodecanol.

6. The method for treating a resin sheet according to claim 1, wherein the cleaning solution contains an alkyl glucoxide having an alkyl group with 8 to 16 carbon atoms.

7. The cleaning solution is CH ３ -(CH ２ ) ｍ -O-(C ２ H ４ O) ｎ 2. The method for treating a resin sheet according to claim 1, wherein the resin sheet contains a polyoxyalkylene alkyl ether represented by -H (m is 11 or more and 15 or less, and n is 2 or more and 17 or less).

8. The method for treating a resin sheet according to claim 1, wherein the boiling point of the cleaning liquid is 120°C or higher.

9. The method for treating a resin sheet according to claim 1, wherein the thickness of the resin sheet is 3.0 μm or more and 150 μm or less.

10. The method for treating a resin sheet according to claim 1, wherein the thickness of the resin sheet is 3.0 μm or more and 12 μm or less.

11. The method for treating a resin sheet according to claim 1, wherein the coverage of the resin coating film with respect to the substrate is 80% or more and 100% or less.

12. The method for treating a resin sheet according to claim 1, wherein the resin coating film is a crosslinked resin coating film in which a diisocyanate compound is detected by pyrolysis GC / MS.

13. The method for treating a resin sheet according to claim 1, further comprising: a rinsing step of removing the cleaning liquid remaining on the substrate after the separating step; and a drying step of drying the substrate after the rinsing step.

14. The method for treating a resin sheet according to claim 13, wherein in the rinsing step, the cleaning liquid remaining on the substrate is removed using a rinsing liquid A containing water as a main component.

15. A method for treating a resin sheet as described in claim 13, wherein in the rinsing step, the cleaning liquid remaining on the substrate is removed using rinsing liquid B, which contains an organic solvent as its main component and has a boiling point of less than 100°C.

16. A method for treating a resin sheet as described in claim 13, wherein the rinsing step comprises: a first rinsing treatment in which rinsing liquid A containing water as its main component is used to remove the cleaning liquid remaining on the substrate; and a second rinsing treatment, performed after the first rinsing treatment, in which rinsing liquid B containing an organic solvent as its main component and having a boiling point lower than that of rinsing liquid A is used to remove the cleaning liquid remaining on the substrate.

17. A method for treating a resin sheet according to claim 1, further comprising a crushing step of crushing the resin sheet to produce crushed pieces before or simultaneously with the separation step.

18. A method for producing recycled raw materials, comprising a recovery step of recovering the substrate from a resin sheet using the resin sheet treatment method described in any one of claims 1 to 17.

Images