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

Abstract

This disclosure provides a method for treating a resin sheet having a substrate and a resin coating, wherein the treatment method includes a separation step of separating the resin coating from the substrate using a cleaning solution, the cleaning solution mainly contains alcohol, and the 14C biomass content of the cleaning solution is 88% or more and 100% or less.

Description

[Technical Field]

[0001] This disclosure relates to a method for processing resin sheets and a method for producing recycled raw materials. [Background technology]

[0002] One approach to addressing environmental issues is resource recycling. For example, Patent Document 1 describes a material comprising at least a first base layer, polyethyleneimine, or polybutadiene, with a mass of 5 to 100 mg / m² per unit area. 2 A method for separating and recovering a laminate is disclosed, comprising a separation step of immersing a laminate having an adhesive layer and a polyolefin resin layer in this order in a desorption liquid to separate the polyolefin resin from the laminate, and a recovery step of recovering the separated polyolefin resin. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Patent No. 7306552 [Overview of the project] [Problems that the invention aims to solve]

[0004] There is a need for a treatment method for resin sheets having a substrate and a resin coating that has a low environmental impact. This disclosure has been made in view of the above circumstances, and its main purpose is to provide a treatment method for resin sheets that can reduce the environmental impact. [Means for solving the problem]

[0005] This disclosure relates to a method for processing a resin sheet having a substrate and a resin coating film, the processing method comprising a separation step of separating the resin coating film from the substrate using a cleaning solution, the cleaning solution containing alcohol as its main component, and the cleaning solution 14Provided is a method for treating a resin sheet, wherein the C biomass content is 88% or more and 100% or less.

[0006] In the present disclosure, provided is a method for producing a recycled raw material, which includes a recovery step of recovering the base material from the resin sheet by using the method for treating the resin sheet described above.

Advantages of the Invention

[0007] In the present disclosure, there is an effect that a method for treating a resin sheet capable of reducing the environmental load can be provided.

Brief Description of the Drawings

[0008] [Figure 1] It is a flowchart illustrating the method for treating a resin sheet in the present disclosure. [Figure 2] It is a schematic cross-sectional view illustrating the resin sheet in the present disclosure. [[ID=--]] [Figure 3] It is a schematic cross-sectional view illustrating the resin sheet in the present disclosure. [Figure 4] It is a schematic cross-sectional view illustrating the resin sheet in the present disclosure. [Figure 5] It is a schematic cross-sectional view illustrating the resin sheet in the present disclosure. [Figure 6] It is a schematic cross-sectional view illustrating the resin sheet in the present disclosure. [Figure 7] It is a schematic cross-sectional view illustrating the resin sheet in the present disclosure. [Figure 8] It is a schematic plan view illustrating the crushed pieces in the present disclosure.

Embodiments for Carrying Out the Invention

[0009] Embodiments will be described below with reference to the drawings. However, this disclosure can be implemented in many different ways and is not limited to the embodiments described below. In addition, the drawings may schematically represent the width, thickness, and shape of each part compared to the actual form in order to make the explanation clearer, but this is merely an example and should not be interpreted as limiting.

[0010] In this specification, when describing a configuration in which one member is placed on top of another member, the terms "on top" or "below" include, unless otherwise specified, both cases: when the other member is placed directly above or below the member in contact with it, and when the other member is placed above or below the member via yet another member. Similarly, when describing a configuration in this specification in which one member is placed on the surface of another member, the terms "on the surface" or "on the side of the surface" include, unless otherwise specified, both cases: when the other member is placed directly above or below the member in contact with it, and when the other member is placed above or below the member via yet another member.

[0011] The following describes in detail the method for processing resin sheets and the method for producing recycled raw materials as described in this disclosure.

[0012] A. Processing method for resin sheets Figure 1 is a flowchart illustrating a resin sheet processing method in this disclosure. As shown in Figure 1, the resin sheet processing method in this disclosure includes a separation step of separating the resin coating from the substrate using a cleaning solution. As shown in Figure 2, the resin sheet 10 has a substrate 1 and a resin coating R in the thickness direction D T In this, they are laminated. In the separation process, the resin coating film R is separated from the substrate 1 using a cleaning solution. The cleaning solution in this disclosure contains alcohol as its main component. 14 The C biomass content is between 88% and 100%.

[0013] According to this disclosure, 14By using a cleaning liquid with a high C biomass content (a cleaning liquid containing a large amount of bio-derived materials), the resin sheet can be processed with a low environmental impact. Furthermore, since the cleaning liquid contains alcohol as a main component, the resin coating can be well separated from the substrate, and a substrate with less residual resin coating can be recovered. Conventionally, resin sheets having a substrate and a resin coating have been discarded as industrial waste without being recycled after use. When the resin sheet is reused as a resource, it is desirable to separate the resin coating from the substrate so that the recycling destination is not limited.

[0014] When separating the resin coating from the substrate using a cleaning liquid, for example, if the cleaning liquid contains a large amount of petroleum-derived materials, the cleaning liquid itself imposes an environmental burden. Usually, since the amount of the cleaning liquid used is significantly larger than the processing amount of the resin sheet, the impact of the cleaning liquid itself on the environment is great. In contrast, in the present disclosure, since the cleaning liquid contains a large amount of bio-derived (particularly plant-derived) materials, the resin sheet can be processed with a low environmental impact.

[0015] 1. Separation step The separation step in the present disclosure is a step of separating the resin coating from the substrate using a cleaning liquid. The cleaning liquid contains alcohol as a main component, and the 14 C biomass content of the cleaning liquid is 88% or more and 100% or less. Also, the separation in the present disclosure includes both peeling and separating the resin coating from the substrate and dissolving the resin coating to separate it from the substrate.

[0016] (1) Cleaning liquid The 14 C biomass content of the cleaning liquid in the present disclosure is 88% or more and 100% or less. 14 The C biomass content is also referred to as the bio-based content, and is an index indicating the ratio of materials derived from organisms among the carbon-containing materials contained in the cleaning liquid. Carbon contains a plurality of isotopes, 12 C and 13 C are stable isotopes and account for most of the carbon. On the other hand, 14 C is a radioactive isotope, 14The concentration of C is approximately 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 concentration of C decreases over time (half-life 5700 years). Therefore, in bio-derived materials... 14 The C concentration is approximately 100 pMC, but in petroleum-derived materials... 14 The C concentration becomes 0.

[0017] For example, if 100% of the materials used are of biological origin, the cleaning solution 14 The biomass content will be 100%. On the other hand, if 100% petroleum-derived materials are used, the cleaning solution will be 14 The carbon biomass content will be 0%. Also, when using 50% bio-derived materials and 50% petroleum-derived materials (based on organic carbon standards), the cleaning solution 14 The C biomass content is 50%. 14 The C biomass content is measured using the AMS (Accelerator Mass Spectrometry) method in accordance with ASTM D6866 (Bio-Based Concentration Test Standard). 14 The C biomass content may be 90% or more, or 95% or more. On the other hand, the washing solution in this disclosure 14 The C biomass content may be 100% or less than 100%.

[0018] (i) alcohol The cleaning solution in this disclosure contains alcohol as its main component. "Main component" refers to the component that is present in the largest quantity by mass among all components contained in the cleaning solution.

[0019] The cleaning solution in this disclosure contains an alcohol of biological origin (particularly plant origin). Of all the alcohols contained in the cleaning solution, the proportion of the biologically derived alcohol is, for example, 80% by mass or more, may be 90% by mass or more, or 95% by mass or more. On the other hand, the above proportion may be 100% by mass or less than 100% by mass. Furthermore, the cleaning solution may contain only one type of biologically derived alcohol, or it may contain two or more types.

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

[0021] The number of hydroxyl groups in a single molecule of alcohol is not particularly limited; it may be one, two, three, or four or more. The molecular weight of the alcohol is also not particularly limited; for example, it may be between 32 and 250, or between 90 and 220. Furthermore, the cleaning solution may contain only one type of alcohol, or two or more types.

[0022] The boiling point of the alcohol contained in the cleaning solution is not particularly limited, but for example, it may be 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 380°C or lower, 360°C or lower, 340°C or lower, or 320°C or lower. The boiling point is the temperature at which the saturated vapor pressure of a liquid equals the external pressure, and corresponds to the temperature at which the liquid boils. In particular, it is preferable that the cleaning solution contains alcohol with a boiling point of 120°C or higher as its main component.

[0023] The proportion of alcohol in the cleaning solution may be, for example, 50% by mass or more, but may also 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, it may not be possible to properly separate the resin coating from the substrate. On the other hand, the proportion of alcohol in the cleaning solution may be 100% by mass or less than 100% by mass.

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

[0025] The boiling point of alcohol A may be, for example, 60°C or higher, 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 may be, for example, 300°C or lower, 280°C or lower, 260°C or lower, or 240°C or lower. The cleaning solution may contain alcohol A as its main component, with 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] Alcohol A is preferably of biological origin (particularly plant-derived). The cleaning solution may contain only one type of alcohol A, or two or more types. The proportion of alcohol A in the cleaning solution is not particularly limited, but 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 alcohol A in the cleaning solution may be 100% by mass or less than 100% by mass.

[0028] Other examples of alcohols contained in the cleaning solution include alcohols having 12 to 18 carbon atoms (hereinafter sometimes referred to as alcohol B). Alcohol B may be a linear compound or a cyclic compound. The linear compound may have a straight chain structure or a branched chain structure. Alcohol B may have a five-membered ring structure or a six-membered ring structure, or it may not have a five-membered ring structure or a six-membered ring structure. The five-membered ring structure and the six-membered ring structure are as described above.

[0029] The boiling point of alcohol B may be, for example, 100°C or higher, but may also 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 may be, for example, 380°C or lower, but may also be 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 solution may contain alcohol B as its main component, with a boiling point within the above range.

[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] Alcohol B is preferably of biological origin (particularly plant-derived). The cleaning solution may contain only one type of alcohol B, or two or more types. The proportion of alcohol B in the cleaning solution is not particularly limited, but 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 alcohol B in the cleaning solution may be 100% by mass or less than 100% by mass.

[0032] The cleaning solution in this 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 to the total of alcohol A and alcohol B is not particularly limited, but 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 above 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 ingredients The cleaning solution in this disclosure may or may not contain water in addition to alcohol. The proportion of water in the cleaning solution may be, for example, 40% by mass or less, 30% by mass or less, or 15% by mass or less.

[0034] The cleaning solution in this disclosure may or may not contain a nonionic surfactant in addition to alcohol. Using a nonionic surfactant improves the separation of resin coatings. The nonionic surfactant is preferably of biological origin (particularly plant-derived).

[0035] Examples of nonionic surfactants include alkyl glucoxides. Alkyl glycosides are compounds in which sugars and higher alcohols are linked by glycosidic bonds. 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 are, for example, CH3-(CH2) m -O-(C2H4O) n It is preferable to have a composition represented by -H (where m is between 11 and 15, and n is between 2 and 17). 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 in the cleaning solution is, for example, 5% by mass or less, but may also be 3% by mass or less, or 1% by mass or less. If the proportion of nonionic surfactants is too high, processing costs may increase. Furthermore, it is preferable that the cleaning solution in this disclosure does not contain inorganic metal salts such as sodium hydroxide. Furthermore, it is preferable that the cleaning solution in this disclosure does not contain petroleum-derived organic solvents.

[0038] (iii) Cleaning solution The boiling point of the cleaning solution 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 solution 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 this disclosure comprises a substrate and a resin coating. As shown in Figure 2, the resin sheet 10 comprises at least a substrate 1 and a resin coating R. The substrate 1 and the resin coating R are arranged in the thickness direction D T They are stacked along that line.

[0040] (i) Base material The base material is preferably a resin film. The resin used in the resin film is not particularly limited, but examples 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 polyesters mentioned above include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), 1,4-polycyclohexylenedimethylene terephthalate, and terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer. Examples of the polyamides mentioned above include nylon 6 and nylon 6,6. Examples of the polyolefins mentioned above include polyethylene (PE), polypropylene (PP), and polymethylpentene. Examples of the vinyl resins mentioned above include polyvinyl chloride, polyvinyl alcohol (PVA), polyvinyl acetate, vinyl chloride-vinyl acetate copolymer, and polyvinylpyrrolidone (PVP).

[0042] Examples of vinyl acetal resins include polyvinyl acetal and polyvinyl butyral. Examples of (meth)acrylic resins include poly(meth)acrylate. "(meth)acrylic" encompasses both "acrylic" and "methacrylic," and "(meth)acrylate" encompasses both "acrylate" and "methacrylate." Examples of imide resins include polyimide and polyetherimide. Examples of cellulose resins include cellophane, cellulose acetate, nitrocellulose, cellulose acetate propionate (CAP), and cellulose acetate butyrate (CAB). Examples of styrene resins 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 for example, it is 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 preferred range when the resin sheet has a relatively thin substrate. A specific example of a resin sheet with a relatively thin substrate is the thermal transfer sheet 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 preferred range when the resin sheet has a relatively thick substrate.

[0044] (ii) resin coating The resin coating is a coating film containing resin. The resin coating may contain a thermoplastic resin, or a cured product (crosslinked product) of a curable resin. The resin coating may be a crosslinked resin coating in which diisocyanate compounds can be detected by pyrolysis GC / MS. Furthermore, the resin used in the resin coating may be one of the resins described for each layer described later. The resin sheet may have only one resin coating, or it may have two or more resin coatings. The resin coating may be arranged on only one side of the substrate, or it may be arranged on both sides of the substrate. The coverage rate of the resin coating on the substrate is not particularly limited, but for example, it is preferably 80% or more and 100% or less. The resin coating varies depending on the type of resin sheet. A typical example of a resin sheet having a resin coating is a thermal transfer sheet, which will be described below.

[0045] (a) Heat transfer sheet Figure 3 is a schematic cross-sectional view illustrating a resin sheet in this disclosure, specifically showing a resin sheet that is a thermal transfer sheet. As shown in Figure 3(a), the resin sheet 10 that is a thermal transfer sheet may have a base material 1 and a colorant layer 2. The colorant layer 2 in Figure 3(a) corresponds to a resin coating film. Also, as shown in Figure 3(b), the resin sheet 10 that is a thermal transfer sheet may have a release layer 3 between the base material 1 and the colorant layer 2. The colorant layer 2 and the release layer 3 in Figure 3(b) correspond to a resin coating film. Also, as shown in Figure 3(c), the resin sheet 10 that is a thermal transfer sheet may have a primer layer 4 between the base material 1 and the colorant layer 2. The colorant layer 2 and the primer layer 4 in Figure 3(c) correspond to a resin coating film. Also, as shown in Figure 3(d), the resin sheet 10 that is a thermal transfer sheet may have a base material 1 and a protective layer 5. The protective layer 5 in Figure 3(d) corresponds to a resin coating film.

[0046] (a-1) Color material layer As shown in Figure 3(a), the resin sheet 10, which is a heat transfer sheet, may have a colorant layer 2. The colorant layer 2 contains a colorant and a binder. Examples of the colorant's hue include magenta, yellow, cyan, and black.

[0047] The above-mentioned colorants may be pigments or dyes. Examples of colorants include carbon black, acetylene black, lamp black, black soot, iron black, aniline black, silica, calcium carbonate, titanium dioxide, cadmium red, cadmopon 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 blue, cobalt, phthalocyanine, anthraquinone, indicoid, cinnabar green, cadmium green, chrome green, phthalocyanine, azomethine, perylene, and aluminum pigments.

[0048] The above-mentioned colorants may be sublimation dyes. Examples of sublimation dyes include diarylmethane dyes, triarylmethane dyes, thiazole dyes, merocyanine dyes, pyrazolone dyes, methine dyes, indoaniline dyes, acetophenoneazomethine dyes, pyrazoloazomethine dyes, xanthene dyes, oxazine dyes, thiazine dyes, azine dyes, acridine dyes, azo dyes, spiropyran dyes, indolinospiropyran dyes, fluorane dyes, naphthoquinone dyes, anthraquinone dyes, and quinophthalone dyes.

[0049] The colorant content 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 colorants such as pigments and dyes are dispersed in a heat-meltable binder, or it may be a sublimation-transfer type colorant layer in which sublimable dyes are 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 type colorant layer may contain wax as a binder. Examples of the above waxes include microcrystalline wax, carnauba wax, paraffin wax, Fischer-Tropsch wax, polyethylene wax, wood wax, beeswax, whale wax, privet wax, wool wax, shellac wax, candelilla wax, petrolactam, polyester wax, partially modified wax, fatty acid esters, and fatty acid amides.

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

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

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

[0055] (a-2) Detachment layer As shown in Figure 3(b), the resin sheet 10, which is a heat transfer sheet, may have a release layer 3 between the substrate 1 and the colorant layer 2. Providing a release layer 3 can improve transferability. The release layer 3 preferably contains a resin. Examples of the resin include (meth)acrylic resin, vinyl resin, styrene resin, cellulose resin, polyester, polyurethane, polyamide, polyimide, and polycarbonate. The release layer 3 may contain a cured product (crosslinked product) of the resin. Examples of curing agents for curing the resin include isocyanate and carbodiimide. The release layer 3 may contain a cured product (crosslinked product) of at least one of an active photocurable monomer and an active photocurable oligomer as the resin. The release layer 3 may also contain additives such as lubricants, ultraviolet absorbers, light stabilizers, and antioxidants.

[0056] (a-3) Primer layer As shown in Figure 3(c), the resin sheet 10, which is a heat transfer sheet, may have a primer layer 4 between the substrate 1 and the colorant layer 2. By providing the primer layer 4, the adhesion between the substrate 1 and the colorant layer 2 can be improved. 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 Figure 3(d), the resin sheet 10, which is a heat transfer sheet, may have a protective layer (OP layer) 5. The protective layer 5 is a transparent layer containing resin. The resin used in the protective layer 5 is not particularly limited, but examples include polyester, polystyrene, polyurethane, (meth)acrylic resin, (meth)acrylic urethane resin, and vinyl chloride-vinyl acetate copolymer. The above resin may be, for example, a silicone-modified resin. The protective layer 5 may also contain a colorant such as a fluorescent whitening agent, or it may not contain a colorant.

[0058] (a-5) Specific examples of heat transfer sheets Figure 4 is a schematic cross-sectional view illustrating a resin sheet (thermal transfer sheet) in this disclosure, specifically showing a melt transfer type thermal transfer sheet. The release layer 3 shown in Figure 4 is normally transferred to the object to be transferred as part of the transfer layer α during thermal transfer. The resin sheet 10 has a thickness direction D T In this configuration, the base material 1 may have a back layer 6 on the side opposite to the colorant layer 2. Providing the back layer 6 can suppress the occurrence of sticking by the thermal head. Similarly, the resin sheet 10 has a thickness direction D T In this configuration, the adhesive layer 7 may be provided on the side opposite to the substrate 1, with respect to the colorant layer 2. Providing the adhesive layer 7 can improve adhesion to the transfer object. Known configurations can be adopted for the release layer 3, back layer 6, and adhesive layer 7.

[0059] Figure 5 is a schematic cross-sectional view illustrating a resin sheet (thermal transfer sheet) in this disclosure, specifically showing a sublimation transfer type thermal transfer sheet. The primer layer 4 shown in Figure 5 improves the adhesion between the substrate 1 and the colorant layer 2. The resin sheet 10 has a thickness direction D T In this configuration, the base material 1 may have a back layer 6 on the side opposite to the colorant layer 2. Furthermore, the resin sheet 10 has a thickness direction D T In this configuration, a second primer layer 8 may be provided between the substrate 1 and the backing layer 6. Providing the second primer layer 8 improves the adhesion between the substrate 1 and the backing layer 6. Known configurations can be used for the primer layer 4, the backing layer 6, and the second primer layer 8.

[0060] Figure 6 is a schematic cross-sectional view illustrating a resin sheet (thermal transfer sheet) in this disclosure, specifically showing a thermal transfer sheet having a protective layer (OP layer). The primer layer 4 shown in Figure 6 improves the adhesion between the protective layer 5 and the adhesive layer 7. The adhesive layer 7 in this disclosure may be a heat seal layer. The resin sheet 10 has a thickness direction D T In this configuration, the base material 1 may have a back layer 6 on the side opposite to the colorant layer 2. Furthermore, the resin sheet 10 has a thickness direction D T In this configuration, a second primer layer 8 may be present between the substrate 1 and the back layer 6. Known configurations can be adopted for the primer layer 4, the back layer 6, and the second primer layer 8.

[0061] (b) Resin sheets other than heat transfer sheets The resin sheet in this 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 or may not be colored. Figure 7 is a schematic cross-sectional view illustrating an example of a resin sheet in this disclosure. As shown in Figure 7, the resin sheet may have a substrate 1 and a printing layer 9. The printing layer 9 contains, for example, a colorant and a binder. The colorant and binder are as described above.

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

[0063] In the separation process, the resin sheet is washed using a washing solution to separate the resin coating from the substrate. The resin sheet used in the washing process may be crushed pieces 11, as shown in Figure 8. That is, a crushing process may be performed before or simultaneously with the separation process to crush the resin sheet and produce crushed pieces. The washing solution is brought into contact with the crushed pieces to separate the resin coating from the substrate. By using crushed pieces, a large amount of resin sheet can be washed. On the other hand, in the case of thin, inflexible resin sheets such as thermal transfer sheets, the crushed pieces tend to aggregate, and the washing solution does not easily penetrate the areas where multiple crushed pieces have aggregated, making it difficult to separate the resin coating from the substrate. In contrast, in this disclosure, by using the washing solution described above, the washing solution can penetrate even the areas where multiple crushed pieces have aggregated, and the resin coating can be well separated from the substrate. The area of ​​the crushed pieces is, for example, 1 cm². 2 Above 15cm 2 The following is 1.5cm 2 More than 10cm 2 The following is also possible: The area of ​​the crushed fragments is determined as the average value of the areas of multiple crushed fragments. On the other hand, the resin sheet used in the washing process does not have to be a crushed fragment.

[0064] When producing crushed fragments, the size and shape of the fragments are not particularly limited, but it is preferable that they be in an appropriate state to increase the frequency of contact between the washing liquid and the object being washed. Examples of crushing devices for crushing resin sheets include jaw crushers, impact crushers, cutter mills, stamp mills, ring mills, roller mills, jet mills, and hammer mills. The conditions for crushing the resin sheet are not particularly limited.

[0065] (3) Separation process The separation process is a process of separating the resin coating from the substrate using a cleaning solution. In the separation process, the mass (amount used) of the cleaning solution relative to the mass (amount processed) of the resin sheet is, for example, 10 times or more, may be 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 solution is too small, the resin coating may not be able to be separated from the substrate properly. On the other hand, the mass (amount used) of the cleaning solution relative to the mass (amount processed) of the resin sheet is, for example, 600 times or less, may be 550 times or less, or 500 times or less. If the mass (amount used) of the cleaning solution is too large, a large amount of cleaning solution will be required, which may reduce the processing efficiency.

[0066] The method for cleaning the resin sheet using a cleaning solution is not particularly limited, but one example is immersing the resin sheet in the cleaning solution. The temperature of the cleaning solution during immersion is not particularly limited, but for example, it may be 25°C or higher and 100°C or lower, or 30°C or higher and 80°C or lower. The immersion time may be, for example, 1 minute or more and 24 hours or less.

[0067] In the separation process, it is preferable to agitate the cleaning solution in which the resin sheet is immersed. By agitating, the resin coating can be separated from the substrate more effectively. When agitating the cleaning solution in which the resin sheet is immersed, media such as beads may or may not be used. In the former case, the media dispersed in the cleaning solution comes into contact with the resin sheet, allowing for better separation of the resin coating from the substrate. On the other hand, in the latter case, foam generation can be suppressed compared to the former. The cleaning agent may or may not contain additives such as activated carbon, anti-re-adhesion agents, and defoaming agents. The separation process may be performed once or two 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 process The resin sheet processing method in this disclosure preferably includes a rinsing step to remove any remaining cleaning solution from the substrate after the separation step. The rinsing step can also facilitate the separation of the resin coating and the substrate.

[0069] In the rinsing process, a rinsing solution is usually used to remove any remaining cleaning solution from the substrate. Examples of rinsing solutions include water. Among these, warm water is preferred because it efficiently removes the remaining cleaning solution from the substrate. The temperature of the warm water is, for example, 35°C to 60°C. Alternatively, the rinsing solution may be an organic solvent. The rinsing solution may contain only one type of organic solvent, or two or more types. Furthermore, the organic solvent is preferably of biological origin (especially plant-derived). 14 The C biomass content 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 rinsing solution may be water (including hot water), an organic solvent, or a mixture of water and an organic solvent. Here, a rinsing solution containing water as the main component is referred to as rinsing solution A. The proportion of water in rinsing solution 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. On the other hand, the proportion of water in rinsing solution A may be 100% by mass or less than 100% by mass. The boiling point of rinsing solution A may be, for example, 80°C or higher and 120°C or lower, or 90°C or higher and 110°C or lower.

[0071] Let rinsing solution B be a rinsing solution mainly composed of an organic solvent. The proportion of the organic solvent in rinsing solution B is, for example, 50% by mass or more, may be 70% by mass or more, may be 80% by mass or more, or may be 90% by mass or more. On the other hand, the proportion of the organic solvent in rinsing solution B may be 100% by mass or less than 100% by mass. The boiling point of rinsing solution B is, for example, 40°C or higher and less than 100°C, or 50°C or higher and 85°C or lower. It is preferable that the boiling point of rinsing solution B is lower than the boiling point of rinsing solution A. The difference between the boiling point of rinsing solution A and the boiling point of rinsing solution B is, for example, 10°C or more, may be 15°C or higher, or may be 20°C or higher. On the other hand, the difference between the boiling point of rinsing solution A and the boiling point of rinsing solution B is, for example, 60°C or less.

[0072] In the rinsing process, a removal treatment to remove residual cleaning solution from the substrate using a rinsing solution may be performed once or two or more times. When the removal treatment is performed two or more times, the same rinsing solution may be used for each removal treatment, or different rinsing solutions may be used. If the rinsing solution used for the nth removal treatment (where n is an integer of 1 or more) is rinsing solution X, and the rinsing solution used for the (n+1)th removal treatment is rinsing solution Y, it is preferable that rinsing solution Y has a lower boiling point than rinsing solution X. This is because it is possible to reduce the drying temperature in the subsequent drying process. For example, if rinsing solution X is water, it is preferable that rinsing solution Y is a liquid with a lower boiling point than water, that is, a liquid with a boiling point of less than 100°C. Examples of liquids with a lower boiling point than water include ethanol (boiling point 78.4°C) and isopropyl alcohol (boiling point 82.3°C). Alternatively, the liquid with a lower boiling point than water may be one of the organic solvents mentioned above.

[0073] Rinsing solution X may be rinsing solution A as described above, and rinsing solution Y may be rinsing solution B as described above. That is, the rinsing process preferably includes a first rinsing treatment using rinsing solution A to remove the cleaning solution remaining on the substrate, and a second rinsing treatment after the first rinsing treatment using rinsing solution B, which has a lower boiling point than rinsing solution A, to remove the cleaning solution remaining on the substrate. In particular, the boiling point of rinsing solution B is preferably less than 100°C. If the boiling point of rinsing solution B is too high, drying residue is likely to occur, which may result in problems in subsequent processes such as molding. On the other hand, if the boiling point of rinsing solution B is too low, the volatilization of rinsing solution B may reduce production stability. Examples of equipment used in the rinsing process include mechanical mixers, Henschel mixers, tumbler mixers, and ultrasonic devices.

[0074] 3.Drying process The resin sheet processing method in this disclosure may include a drying step after the separation step in which the substrate separated from the resin coating is dried. Furthermore, if the resin sheet processing method includes the rinsing step described above, the resin sheet processing method may include a drying step after the rinsing step.

[0075] The drying temperature in the drying process is not particularly limited, but 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 process 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 dry the substrate sufficiently. On the other hand, if the drying temperature is too high, the processing efficiency may decrease. Also, if the drying temperature is too low, the drying performance may decrease, and if the drying temperature is too high, the dried material may suffer thermal damage.

[0076] The drying time in the drying process 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 process 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 dry the substrate sufficiently. On the other hand, if the drying time is too long, the processing efficiency may decrease. Also, if the drying time is too short, the drying may be insufficient, and if the drying time is too long, the work efficiency may decrease.

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

[0078] B. Method for manufacturing recycled raw materials The method for producing recycled raw materials in this disclosure includes a recovery step of recovering the base material from the resin sheet using the processing method described in "A. Processing method for resin sheet" above.

[0079] According to this disclosure, by processing the resin sheet using the processing method described above, it is possible to obtain recycled raw materials while reducing the environmental burden. The recovery process is the same as described in "A. Processing Method for Resin Sheets" above, so it is omitted here.

[0080] The method for producing recycled raw materials may, if necessary, include a pelletizing step in which the recovered base material is processed into pellets. This yields recycled raw materials in pellet form.

[0081] This disclosure is not limited to the embodiments described above. The embodiments described above are illustrative, and any configuration that is substantially identical to the technical idea described in the claims of this disclosure and achieves similar effects is included within the technical scope of this disclosure. [Examples]

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

[0083] Meanwhile, 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. (The following sentence is incomplete and cannot be translated.) 14The biomass content of C is almost 0%, and the washing solution 6 14 The C biomass content was 0%.

[0084] [Table 1]

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

[0086] [Table 2]

[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 microcut, and the shredding speed was set to a maximum of 12 m / min. Then, washing solution 1 was added to a container and heated in a water bath until the temperature of washing solution 1 reached 50°C. Next, 1.0 g of the shredded pieces was placed in a 100 mL beaker, and then 49 g of the heated washing 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 a mesh size of 2 mm.

[0088] Next, the recovered crushed fragments were placed in 49g of 50°C water and stirred at room temperature at 300 rpm for 5 minutes (rinsing step). After stirring, the crushed fragments (base material) were collected using a sieve with a mesh size of 2 mm, the water was removed, and the material was hot-air dried in an oven at 140°C for 3 hours (drying step). This yielded the washed crushed fragments (base material).

[0089] [Examples 2-4] The crushed fragments (substrate) after washing were obtained in the same manner as in Example 1, except that washing solutions 2 to 4 were used instead of washing solution 1.

[0090] [Examples 5-8] The washed crushed pieces (base material) 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 crushed fragments (base material) after washing were obtained in the same manner as in Example 1, except that the hot water used in the rinsing process was changed to 25°C water.

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

[0093] [Example 11] The rinsing process (first rinse) was carried out in the same manner as in Example 1. Next, after stirring, the crushed pieces (base material) were collected using a sieve with a mesh size of 2 mm. Next, the crushed pieces were placed in 49 g of ethanol (EtOH, boiling point 78.4°C) at 25°C and stirred at room temperature at 300 rpm for 5 minutes (second rinse). Next, after stirring, the crushed pieces (base material) were collected using a sieve with a mesh size of 2 mm and dried with hot air in an oven at 100°C for 3 hours (drying process). This obtained the washed crushed pieces (base material).

[0094] [Examples 12-17] The crushed fragments (substrate) after washing were obtained in the same manner as in Example 11, except that the type of resin sheet, the presence or absence of the first rinsing treatment, and the type of rinsing solution in the second rinsing 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] The crushed pieces (substrate) after washing were obtained in the same manner as in Example 1, except that washing solution 5 was used instead of washing solution 1, and the drying temperature in the drying process was changed from 140°C to 110°C.

[0096] [Comparative Example 2] The washed crushed pieces (base material) were 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] The crushed pieces (substrate) after washing were obtained in the same manner as in Example 1, except that washing solution 6 was used instead of washing solution 1, and the drying temperature in the drying process was changed from 140°C to 120°C.

[0098] [evaluation] (Remaining rate of resin coating) The surface of the crushed fragments before and after washing was photographed with a microscope (20x magnification). These images were scanned using a scanner (CanoScan9000F) with a resolution of 600 dpi, grayscale color mode, and no color correction. The scanned images were then binarized using image analysis software (ImageJ), and the number of dots from 0 to 200 gradations was counted. The remaining resin coating percentage was calculated using the following formula. Residual rate of resin coating (%) = (Number of dots after cleaning) / (Number of dots before cleaning) × 100

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

[0100] (Residual rate of cleaning solution) The crushed fragments after the rinsing process were measured using GC-MS (JEOL JMS-Q1500GC and JMS-T1000CV). The total amount of tetrahydrofurfuryl alcohol and 1-dodecanol detected was calculated, and the residual rate of the washing solution was determined using the following formula. Residual rate of the washing solution (%) = {(amount of tetrahydrofurfuryl alcohol detected) + (amount of 1-dodecanol detected)} / (mass of crushed fragments) × 100

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

[0102] [Table 3]

[0103] [Table 4]

[0104] As shown in Tables 3 and 4, in Examples 1 to 17, the residual rate of the resin coating was low, and the resin coating was successfully separated from the substrate. In particular, in Examples 13 and 15, the residual rate of the resin coating was extremely low by performing the first rinse with hot water and the second rinse with IPA, which has a lower boiling point than water. Also, in Examples 1 to 17, 14 Because cleaning solutions 1-4, which have a high C biomass content, were used, the environmental impact was reduced. Furthermore, in Examples 1-17, the residual rate of the resin coating was low, and the residual rate of the cleaning solution was also low. In contrast, in Comparative Examples 1-3, the residual rate of the resin coating was high, and the resin coating could not be properly separated from the substrate.

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

[0106] [1] A method for processing a resin sheet having a base material and a resin coating film, The above processing method includes a separation step of separating the resin coating from the substrate using a cleaning solution. The above cleaning solution contains alcohol as its main component, The above cleaning solution 14 A method for processing resin sheets, wherein the biomass content is between 88% and 100%.

[0107] [2] The above cleaning solution contains alcohol A having a 5-membered ring structure or a 6-membered ring structure as the above alcohol, as described in [1], for the treatment of a resin sheet.

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

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

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

[0111] [6] The above cleaning solution contains an alkyl glucoxide having an alkyl group with 8 to 16 carbon atoms, according to any one of [1] to [5].

[0112] [7] The above cleaning solution is CH3-(CH2) m -O-(C2H4O) n A method for processing a resin sheet according to any one of [1] to [6], comprising a polyoxyalkylene alkyl ether represented by -H (where m is 11 or more and 15 or less, and n is 2 or more and 17 or less).

[0113] [8] The boiling point of the above cleaning solution is 120°C or higher, a method for treating a resin sheet as described in any of [1] to [7].

[0114] [9] The resin sheet thickness is 3.0 μm or more and 150 μm or less, and the method for processing a resin sheet as described in any of [1] to [8].

[0115]

[10] The resin sheet thickness is 3.0 μm or more and 12 μm or less, and the method for processing a resin sheet as described in any of [1] to [9].

[0116]

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

[10] , wherein the coverage rate of the resin coating on the above substrate is 80% or more and 100% or less.

[0117]

[12] The above resin coating is a cross-linked resin coating in which diisocyanate compounds are detected by thermal decomposition GC / MS method, a method for treating a resin sheet according to any one of [1] to

[11] .

[0118]

[13] The above processing method is, After the above separation step, a rinsing step is performed to remove the cleaning solution remaining on the substrate. After the rinsing step described above, a drying step is performed to dry the substrate, A method for processing a resin sheet according to any one of [1] to

[12] , comprising [1].

[0119]

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

[13] , wherein in the rinsing step described above, a rinsing solution A containing water as the main component is used to remove the cleaning solution remaining on the substrate.

[0120]

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

[13] or

[14] , wherein in the rinsing step described above, the cleaning solution remaining on the substrate is removed using rinsing solution B, which contains an organic solvent as its main component and has a boiling point of less than 100°C.

[0121]

[16] The above rinsing process is, A first rinsing treatment is performed using rinsing solution A, which mainly contains water, to remove the cleaning solution remaining on the substrate. A method for treating a resin sheet according to

[13] , comprising: a second rinsing treatment in which, after the first rinsing treatment described above, a rinsing solution B containing an organic solvent as its main component and having a lower boiling point than the rinsing solution A is used to remove the cleaning solution remaining on the substrate.

[0122]

[17] The above processing method is a method for processing 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 above separation step.

[0123]

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

[17] . [Explanation of Symbols]

[0124] 1...Base material 2...color material layer 3... Exfoliation layer 4…Primer layer 5…Protective layer 6…Back layer 7...Adhesive layer 8…Second primer layer 9…Printing layer 10… Resin sheet 11... Fragments

Claims

1. A method for processing a resin sheet having a base material and a resin coating film, The processing method includes a separation step of separating the resin coating film from the substrate using a cleaning solution. The aforementioned cleaning solution contains alcohol as its main component, The cleaning solution contains alcohol A having a five-membered ring structure or a six-membered ring structure as the alcohol, The cleaning solution １４ A method for processing resin sheets, wherein the biomass content is between 88% and 100%.

2. The method for treating a resin sheet according to claim 1, wherein the alcohol A is tetrahydrofurfuryl alcohol.

3. A method for processing a resin sheet having a base material and a resin coating film, The processing method includes a separation step of separating the resin coating film from the substrate using a cleaning solution. The aforementioned cleaning solution contains alcohol as its main component, The cleaning solution contains alcohol B having 12 or more carbon atoms and 18 or fewer as the alcohol, The aforementioned alcohol B is 1-dodecanol, The cleaning solution １４ A method for processing resin sheets, wherein the biomass content is between 88% and 100%.

4. A method for processing a resin sheet having a base material and a resin coating film, The processing method includes a separation step of separating the resin coating film from the substrate using a cleaning solution. The aforementioned cleaning solution contains alcohol as its main component, The washing solution contains an alkyl glucoxide having an alkyl group with 8 to 16 carbon atoms. The cleaning solution １４ A method for processing resin sheets, wherein the biomass content is between 88% and 100%.

5. A method for processing a resin sheet having a base material and a resin coating film, The processing method includes a separation step of separating the resin coating film from the substrate using a cleaning solution. The aforementioned cleaning solution contains alcohol as its main component, The washing solution contains a polyoxyalkylene alkyl ether represented as CH3-(CH2)m-O-(C2H4O)n-H (where m is between 11 and 15, and n is between 2 and 17), The cleaning solution １４ A method for processing resin sheets, wherein the biomass content is between 88% and 100%.

6. The method for processing a resin sheet according to any one of claims 1 to 5, wherein the boiling point of the cleaning solution is 120°C or higher.

7. The method for processing a resin sheet according to any one of claims 1 to 5, wherein the thickness of the resin sheet is 3.0 μm or more and 150 μm or less.

8. The method for processing a resin sheet according to any one of claims 1 to 5, wherein the thickness of the resin sheet is 3.0 μm or more and 12 μm or less.

9. A method for processing a resin sheet according to any one of claims 1 to 5, wherein the coverage rate of the resin coating on the substrate is 80% or more and 100% or less.

10. The method for treating a resin sheet according to any one of claims 1 to 5, wherein the resin coating is a crosslinked resin coating in which a diisocyanate compound is detected by thermal decomposition GC / MS method.

11. The aforementioned processing method is: After the separation step, a rinsing step is performed to remove the cleaning solution remaining on the substrate, After the rinsing step, a drying step is performed to dry the substrate, A method for processing a resin sheet according to any one of claims 1 to 5, comprising:

12. The method for processing a resin sheet according to claim 11, wherein in the rinsing step, the cleaning solution remaining on the substrate is removed using a rinsing solution A which mainly contains water.

13. The method for treating a resin sheet according to claim 11, wherein in the rinsing step, the cleaning solution remaining on the substrate is removed using a rinsing solution B which mainly contains an organic solvent and has a boiling point of less than 100°C.

14. The rinsing process described above is: A first rinsing treatment is performed using rinsing solution A, which mainly contains water, to remove the cleaning solution remaining on the substrate. A method for processing a resin sheet according to claim 11, comprising: a second rinsing treatment, after the first rinsing treatment, using rinsing solution B which mainly contains an organic solvent and has a lower boiling point than rinsing solution A, to remove the cleaning solution remaining on the substrate.

15. The processing method for a resin sheet according to any one of claims 1 to 5, wherein the processing method comprises a crushing step of crushing the resin sheet to produce crushed pieces, either before or simultaneously with the separation step.

16. A method for producing recycled raw materials, comprising a recovery step of recovering the base material from the resin sheet using the resin sheet processing method described in any one of claims 1 to 5.

Images