Method for recycling resin body

Abstract

To provide a method for recycling a resin body which reduces environmental loads, and can stabilize quality.SOLUTION: A method for recycling a resin body includes the steps of: recovering a resin body in which at least 90% or more is a material of the same resin; crushing the recovered resin body; stirring the crushed resin body in water, and thereby removing a foreign substance from the resin body; drying and selecting the resin body from which the foreign substance is removed; crushing the selected resin body; melting the crushed resin body; molding a resin pellet 1 from the molten resin body; and cooling the resin pellet 1.SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present disclosure relates to a method for recycling a resin body. [Background technology]

[0002] Conventionally, tubular containers including aluminum foil have been known (for example, Patent Document 1). Patent Document 1 discloses a tubular container that can suppress the occurrence of wrinkles in the aluminum foil layer at the side seam portion when the side seam is made into a cylindrical body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2022-187819 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, such tube containers containing aluminum foil are generally incinerated without recycling the resin.

[0005] On the other hand, in recent years, there has been an increasing demand for the creation of a recycling-based society. For this reason, there is a demand to reduce the environmental load by recycling resins from tube containers and the like using various methods. In addition, when recycling resins, there is a demand to stabilize the quality of the recycled resins.

[0006] The present disclosure has been made in consideration of these points, and aims to provide a method for recycling resin bodies that can reduce the environmental load and stabilize the quality. [Means for solving the problem]

[0007] The embodiments of the present disclosure relate to the following [1] to [3].

[0008] [1] A method for recycling a resin body, comprising the steps of: recovering resin bodies, at least 90% of which are made of the same resin material; Crushing the recovered resin body; removing foreign matter from the resin body by stirring the crushed resin body in water; drying and sorting the resin body from which the foreign matter has been removed; A step of crushing the selected resin body; Melting the pulverized resin body; forming a resin pellet from the molten resin body; and cooling the resin pellets.

[0009] [2] The method for recycling a resin body according to [1], wherein in the step of removing foreign matter from the resin body, removal of foreign matter and cleaning of the resin body are carried out using a cleaning liquid containing a surfactant.

[0010] [3] The recycling method according to [1] or [2], wherein in the step of drying and sorting the resin body, the resin body from which the foreign matter has been removed is sorted by a specific gravity sorting method, a wind sorting method, or an electrostatic sorting method. Effect of the Invention

[0011] According to the present disclosure, it is possible to reduce the environmental impact and stabilize the quality of the recycled resin. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a perspective view showing a resin pellet according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view showing a resin film according to an embodiment. [Diagram 3] FIG. 3 is a cross-sectional view showing a laminate according to an embodiment. [Figure 4] FIG. 4 is a cross-sectional view showing a laminate according to an embodiment. [Diagram 5] FIG. 5 is a partial vertical cross-sectional view showing a tube container according to one embodiment. [Figure 6] FIG. 6 is a plan view of a bag according to one embodiment. [Figure 7] FIG. 7 is a flow chart illustrating a recycling method and a method for producing resin pellets according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] An embodiment will be described below with reference to the drawings. FIGS. 1 to 7 are diagrams showing an embodiment. Each of the figures shown below is a schematic diagram. Therefore, the size and shape of each part are appropriately exaggerated to facilitate understanding. In addition, the present invention can be modified appropriately within the scope of the technical concept. In each of the figures shown below, the same parts are given the same reference numerals, and some detailed explanations may be omitted. In addition, the numerical values ​​such as the dimensions of each member and the material names described in this specification are examples of an embodiment, and can be appropriately selected and used without being limited thereto. In this specification, terms that specify shapes and geometric conditions, such as parallel, orthogonal, and vertical, are interpreted to include substantially the same state in addition to their strict meanings.

[0014] <Resin pellets> As shown in Fig. 1, the resin pellet 1 is a resin lump with a maximum width of about 1 mm to 7 mm. In the illustrated example, the resin pellet 1 has a cylindrical shape. Although not shown, the resin pellet 1 may have a spherical shape. The resin pellet 1 is a resin lump produced by cutting extruded resin (strands) extruded in a string shape from a filter into granules in a pellet production device (not shown).

[0015] The resin pellets 1 contain recycled recycled resin. This can reduce the environmental load of the resin film 5 and the like produced from the resin pellets 1. In this specification, the term "recycled recycled resin" refers to a resin material obtained by removing foreign matter and dirt from the resin body. The resin body may be a resin product used in the market, or a material generated in a resin product manufacturing process before it is released to the market. In other words, the recycled resin may be a resin obtained by post-consumer recycling (PCR) or a resin obtained by post-industrial recycling (PIR). In addition, when the recycled resin is produced by post-consumer recycling (PCR), the recycled recycled resin may be a resin recycled from another tube container 40 or the like produced from the resin pellets 1 (the resin film 5, the laminate 10, 20, the tube container 40, or the packaging bag 70 described later). Furthermore, the recycled recycled resin may be a resin recycled from an item (for example, a plastic product collected at a retail store, or a plastic sorted by a collector) different from the tube container 40 or the like produced from the resin pellets 1.

[0016] When obtaining recycled regenerated resin, first, the resin body is sorted and crushed. Then, foreign matter is removed from the crushed resin body. As a result, flakes from which foreign matter has been removed are obtained. At this time, if necessary, the crushed resin body may be washed with water, hot water, a surfactant, an alkaline cleaning solution, or the like to remove dirt attached to the flakes. In this case, for example, an aqueous solution of a surfactant and an alkaline cleaning solution may be heated to about 80°C, and the crushed resin body may be washed with the aqueous solution. Then, the flakes are further treated at high temperature and reduced pressure for a certain period of time to obtain a resin material from which foreign matter and dirt have been removed (i.e., recycled regenerated resin).

[0017] At least 90% or more of the recycled resin (resin pellets 1) is a material of the same resin system. In this case, the recycled resin can be classified as a so-called mono-material material, and can be suitably used for producing a packaging container made of the same material (so-called mono-material packaging container). The recycled resin may also be produced from a mono-material packaging container. This makes it possible to easily increase the content of the material of the same resin system in the recycled resin (resin pellets 1). The material constituting the recycled resin may be polyethylene or polypropylene. In other words, the resin pellets 1 may contain polyethylene or polypropylene as a main component.

[0018] Here, for example, polyethylene includes high density polyethylene and linear low density polyethylene. These high density polyethylene and linear low density polyethylene are classified as "materials of the same resin system" in this specification. On the other hand, for example, polyethylene and polyester are not classified as materials of the same resin system.

[0019] The resin pellets 1 may further contain an ethylene-vinyl alcohol copolymer (EVOH). In the laminate constituting the body tube of the tube container, a layer containing an ethylene-vinyl alcohol copolymer may be provided as a barrier layer. Therefore, when the resin pellets 1 are produced from such a tube container, the resin pellets 1 contain an ethylene-vinyl alcohol copolymer. In this case, the content of the ethylene-vinyl alcohol copolymer in the resin pellets 1 may be 5% by weight or less.

[0020] Furthermore, the resin pellet 1 may further contain metal particles. In the laminate constituting the body tube of the tube container, a metal foil (e.g., aluminum foil, etc.) or a vapor-deposited film of a metal (e.g., aluminum, etc.) may be provided as a barrier layer. Therefore, when the resin pellet 1 is produced from such a tube container, the resin pellet 1 contains metal particles. In this case, the content of the metal particles in the resin pellet 1 may be 1% by weight or less.

[0021] The resin pellets 1 may be produced by a so-called hot cut method in which the molten resin is cut in a molten state without being cooled. Alternatively, the resin pellets 1 may be produced by a so-called cold cut method in which the molten resin is cut after being cooled. When cooling the molten resin in this way, a cooling method such as a water cooling method in which water is directly poured onto the molten resin, a mist cooling method in which water is turned into a mist and poured onto the molten resin, or an air cooling method in which air is blown onto the molten resin may be used.

[0022] Next, the resin film 5 will be described.

[0023] <Resin film> The resin film 5 shown in Fig. 2 is a film made from the above-mentioned resin pellets 1. The resin film 5 can be made, for example, by using the resin pellets 1 and an inflation method or other molding method. This resin film 5 contains recycled resin. In addition, at least 90% or more of the recycled resin is a material of the same resin system.

[0024] As described above, the resin film 5 is a film produced from the above-mentioned resin pellets 1. Therefore, the resin film 5 may further contain an ethylene-vinyl alcohol copolymer. In this case, the content of the ethylene-vinyl alcohol copolymer in the resin film 5 may be 5% by weight or less.

[0025] Furthermore, the resin film 5 may further contain metal particles. In this case, the content of the metal particles in the resin film 5 may be 1% by weight or less.

[0026] Furthermore, the resin film 5 may further contain virgin resin. Note that "virgin resin" refers to a resin material that has not been subjected to a recycling process. By containing virgin resin in the resin film 5 in this way, the hygiene of the resin film 5 can be improved.

[0027] Next, the laminates 10 and 20 including the above-mentioned resin film 5 will be described.

[0028] <Laminate> As shown in Fig. 3, the laminate 10 includes a first resin layer 11, a second resin layer 12, and a third resin layer 13, which are arranged in this order from an outer surface 101 to an inner surface 102. In the laminate 10 shown in Fig. 3, the first resin layer 11 constitutes the outer surface 101 of the laminate 10, and the third resin layer 13 constitutes the inner surface 102 of the laminate 10. In this case, at least one of the first resin layer 11 and the second resin layer 12 may have the above-mentioned resin film 5.

[0029] As shown in Fig. 4, the laminate 20 includes an outer layer 21 and an inner layer 22. In the laminate 20 shown in Fig. 4, the outer layer 21 constitutes an outer surface 201 of the laminate 20, and the inner layer 22 constitutes an inner surface 202 of the laminate 20. In this case, the outer layer 21 may include the resin film 5 described above.

[0030] Each layer of the laminates 10 and 20 will now be described.

[0031] <<First resin layer>> The first resin layer 11 is a layer for bonding the laminates 10 together, and is a so-called sealant layer. This first resin layer 11 is a layer that becomes the outermost layer when, for example, a tube container 40 described later is produced from the laminate 10. As described above, the first resin layer 11 may have a resin film 5. In addition to the above-mentioned resin film 5, a material that melts and fuses by heat may be used as a material constituting the first resin layer 11. For example, polyolefin may be used for the first resin layer 11. More specifically, the first resin layer 11 may be made of one or more resins such as low-density polyethylene (LDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), linear low-density polyethylene (LLDPE), polypropylene, acid-modified polyolefin resins such as polyethylene or polypropylene modified with acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, or other unsaturated carboxylic acids, polyvinyl acetate resins, polyester resins, polystyrene resins, polyacrylonitrile, saturated polyesters, or polyvinyl alcohol.

[0032] In addition, when the first resin layer 11 contains polyethylene or polypropylene, the polyethylene may be biomass polyethylene, and the polypropylene may be biomass polypropylene. Since the first resin layer 11 contains a resin derived from biomass, the amount of fossil fuel used can be reduced, and the environmental load of the laminate 10 can be reduced. In addition, biomass polyethylene is a monomer polymer containing ethylene derived from biomass. Since ethylene derived from biomass is used as the raw material monomer, the polyolefin obtained by polymerization is derived from biomass. The content of ethylene derived from biomass in the raw material monomer does not need to be 100% by mass, and is, for example, preferably 50% or more, more preferably 80% or more. The raw material monomer may contain ethylene derived from fossil fuel, and may contain α-olefin monomers such as butylene, hexene, and octene.

[0033] For example, biomass-derived ethylene can be produced using biomass-derived ethanol as a raw material. In particular, it is preferable to use biomass-derived fermented ethanol obtained from a plant raw material. The plant raw material is not particularly limited, and any conventionally known plant can be used. Examples of conventionally known plants include corn, sugarcane, beet, and manioc.

[0034] The material for the first resin layer 11 may be a material to which, for example, an antiblocking agent, a lubricant (fatty acid amide, etc.), a flame retardant, an inorganic or organic filler, etc. are optionally added.

[0035] In the present embodiment, the thickness of the first resin layer 11 is preferably not less than 50 μm and not more than 250 μm.

[0036] <<Second resin layer, outer layer>> The second resin layer 12 is, for example, a layer for supporting the first resin layer 11 and the third resin layer 13, etc., and for increasing the strength of the entire laminate 10. The outer layer 21 is, for example, a layer for supporting the inner layer 22, and for increasing the strength of the entire laminate 20. As described above, the second resin layer 12 and the outer layer 21 may have a resin film 5. In addition to the above-mentioned resin film 5, a resin film constituting a normal packaging material may be appropriately used as the second resin layer 12 and the outer layer 21. As a material for constituting the second resin layer 12 and the outer layer 21, for example, a polyester-based resin, a polyamide-based resin, a polyaramid-based resin, a polyolefin-based resin, a polycarbonate-based resin, a polyacetal-based resin, a fluorine-based resin, a film or sheet of other tough resin, and others may be used. As an example, the second resin layer 12 and the outer layer 21 may contain polyethylene terephthalate. When the second resin layer 12 and the outer layer 21 contain a polyester-based resin, the polyester-based resin may contain a biomass polyester. Biomass polyester refers to polyester obtained from raw materials containing monomers derived from biomass.

[0037] The resin film or sheet may be an unstretched film, or a uniaxially or biaxially stretched film, etc. Among these, in the present embodiment, a biaxially stretched polyester resin film is preferred because of its excellent printability.

[0038] In the present embodiment, the thickness of each of the second resin layer 12 and the outer layer 21 is preferably not less than 10 μm and not more than 25 μm.

[0039] <<Third resin layer, inner layer>> The third resin layer 13 is a layer for bonding the laminates 10 together, and is a so-called sealant layer. For example, the third resin layer 13 is a layer that becomes the innermost layer when a tube container 40 (described later) is produced from the laminate 10. The third resin layer 13 is preferably made of a virgin resin. In this way, the third resin layer 13 that becomes the innermost layer of the tube container 40 is made of a virgin resin, thereby improving the hygiene of the tube container 40.

[0040] The inner layer 22 is a layer for bonding the laminates 20 together, and is a so-called sealant layer. For example, the inner layer 22 is a layer that becomes the innermost layer when a packaging bag 70 (described later) is produced from the laminate 20. The inner layer 22 is preferably made of virgin resin. In this way, the inner layer 22 that becomes the innermost layer of the packaging bag 70 is made of virgin resin, and thus the hygiene of the packaging bag 70 can be improved.

[0041] The material constituting the third resin layer 13 and the inner layer 22 is a material that melts and fuses by heat. For example, polyolefin may be used for the third resin layer 13 and the inner layer 22. More specifically, for example, the third resin layer 13 and the inner layer 22 may be made of one or more resins such as low density polyethylene (LDPE), medium density polyethylene (MDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), polypropylene, acid-modified polyolefin resins obtained by modifying polyolefin resins such as polyethylene or polypropylene with acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, itaconic acid, or other unsaturated carboxylic acids, polyvinyl acetate resins, polyester resins, polystyrene resins, polyacrylonitrile, saturated polyesters, or polyvinyl alcohol. When the third resin layer 13 and the inner layer 22 contain polyethylene, the polyethylene may contain a biomass-derived component. Since the third resin layer 13 and the inner layer 22 contain a resin derived from biomass, the amount of fossil fuel used can be reduced, and the environmental load of the laminates 10, 20 can be reduced.

[0042] The material for the third resin layer 13 and the inner layer 22 may be a material to which, for example, an antiblocking agent, a lubricant (fatty acid amide, etc.), a flame retardant, an inorganic or organic filler, etc. are optionally added.

[0043] In the present embodiment, the thickness of each of the third resin layer 13 and the inner layer 22 is preferably not less than 50 μm and not more than 250 μm.

[0044] <<Other layers>> As other layers, a printed layer, a barrier layer, an intermediate layer, and the like may be further provided. The printed layer is a layer for enhancing the design of the packaging material, etc. This printed layer is a layer on which a picture such as a predetermined character, figure, pattern, or color coding is formed by ink. A known ink may be used as the ink. For example, the ink may contain at least one of an organic pigment and an inorganic pigment, and a binder resin, and may further contain various additives as necessary. The printed layer can be formed, for example, on the second resin layer 12 or the outer layer 21 by a known printing method, such as gravure printing, offset printing, letterpress printing, or screen printing.

[0045] The barrier layer is a layer for suppressing the permeation of oxygen gas, water vapor, etc. By providing the laminates 10 and 20 with a barrier layer, the permeation of oxygen gas, etc. can be suppressed, and weight loss and deterioration of the contents can be effectively suppressed.

[0046] The barrier layer may be, for example, a vapor-deposited film of an inorganic substance or an inorganic oxide, or a layer made of a gas barrier resin such as an ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polyvinyl alcohol, or MXD6, etc. The barrier layer may also be formed by a combination of the above-mentioned vapor-deposited films or layers made of gas barrier resins.

[0047] In order to ensure the visibility of the contents, the barrier layer is preferably transparent. In this case, a vapor deposition film of an inorganic oxide can be particularly preferably used as the barrier layer. The inorganic oxide forming the vapor deposition film may be an inorganic oxide that has transparency and gas barrier properties against oxygen gas, water vapor, and the like. Examples of such inorganic oxides include oxides such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, hafnium oxide, and barium oxide. Among these, aluminum oxide and silicon oxide can be particularly preferably used in terms of gas barrier properties and production efficiency.

[0048] The intermediate layer is a layer for increasing the strength of the entire laminate 10, 20. The intermediate layer is preferably made of a material having impact resistance and pinhole resistance. For example, a polyamide resin film such as a biaxially oriented nylon film may be used as the intermediate layer. The thickness of the intermediate layer may be appropriately determined depending on the application and function of the laminate 10, 20. The thickness of the intermediate layer may be, for example, about 15 μm or more and 25 μm or less.

[0049] The method for laminating the first resin layer 11, the second resin layer 12, the third resin layer 13, etc., may be, for example, a wet lamination method, a dry lamination method, a solventless dry lamination method, an extrusion lamination method, a co-extrusion lamination method, an inflation method, or any other method. In addition, when performing the above-mentioned lamination, the films constituting each layer may be subjected to a pretreatment such as a corona treatment or an ozone treatment.

[0050] The recycled resin content may be 20% by weight or more and 80% by weight or less in such laminates 10, 20. When the recycled resin content is 20% by weight or more, the environmental impact of the laminates 10, 20 can be effectively reduced. Furthermore, when the recycled resin content is 80% by weight or less, the hygienic properties of the tube container 40 or the packaging bag 70 made from the laminates 10, 20 can be improved.

[0051] Such laminates 10, 20 may be used to make, for example, tube containers 40 or packaging bags 70.

[0052] Next, a description will be given of a tube container 40 or a packaging bag 70 including the laminates 10, 20 according to the present embodiment. Here, the tube container 40 will be described.

[0053] 5, the tube container 40 includes a body tube 41, which is a laminated molded tube, and a head member 43 joined to one end 42 of the body tube 41. The body tube 41 has a generally cylindrical shape. The body tube 41 has a laminate 10. In this case, the body tube 41 may be configured such that an outer surface 101 of the laminate 10 faces away from the contents and an inner surface 102 faces the contents.

[0054] The body tube 41 has a body seal portion 44 that joins the laminates 10 together. This body seal portion 44 is formed along the longitudinal direction of the body tube 41. Such a body tube 41 may be obtained, for example, by rolling the laminate 10 into a cylindrical shape, overlapping opposing ends, and joining them together, for example, by heat sealing.

[0055] The body tube 41 also has a bottom seal portion 45 that joins the stacks 10 together. This bottom seal portion 45 is a portion where the stacks 10 are joined together near an opening (not shown) formed at the other end 46 of the body tube 41 after an appropriate amount of content C is filled into the container.

[0056] The head member 43 has a shoulder portion 47 and a mouth portion 48. A cap 49 is attached to the mouth portion 48. The head member 43 is molded by, for example, compression molding. The head member 43 is made of, for example, a resin material such as high density polyethylene (HDPE).

[0057] Next, a packaging bag 70 including the laminate 20 according to the present embodiment will be described.

[0058] 6, the packaging bag 70 may be a standing pouch formed using the above-mentioned laminate 20. In this case, the packaging bag 70 may be configured such that the outer surface 201 of the laminate 20 faces away from the contents and the inner surface 202 faces the contents.

[0059] The packaging bag 70 includes a pair of side seal portions 71, a bottom seal portion 72, and an upper seal portion 73. Of the pair of side seal portions 71, one of the side seal portions 71 is separated into an upper portion and a lower portion via an unsealed portion 74. A protruding seal portion 75 is formed to protrude into the storage space so as to be connected to the upper portion and the lower portion of the side seal portion 71. The unsealed portion 74 is formed from the outer edge of the packaging bag 70 toward the storage space, and separates the unsealed portion 74 from the storage space. The unsealed portion 74 is formed to protrude toward the storage space beyond the inner edge of one of the side seal portions 71.

[0060] In this packaging bag 70, a steam escape mechanism is formed by the protruding sealed portion 75 and the unsealed portion 74. When the packaging bag 70 is heated in a microwave oven, the protruding sealed portion 75 peels back and reaches the unsealed portion 74, allowing steam to escape from the unsealed portion 74, thereby reducing the internal pressure of the packaging bag 70. Note that the unsealed portion 74 may have a through portion such as a hole or a cut.

[0061] The packaging bag 70 may be produced by folding the laminate 20 in two or three. The packaging bag 70 may be produced by preparing two sheets of the laminate 20 and overlapping the inner layer 22 of the front laminate 20 with the inner layer 22 of the back laminate 20 facing each other. The packaging bag 70 may be produced as a gusset-type packaging bag by inserting the folded laminate 20 between the front laminate 20 and the back laminate 20 and heat sealing the laminate 20. The packaging bag 70 may be produced as a bag of various shapes by adopting a heat seal type such as a side seal type, a two-sided seal type, a three-sided seal type, a four-sided seal type, an envelope seal type, a grooving seal type (pillow seal type), a pleated seal type, a flat bottom seal type, or a square bottom seal type.

[0062] In the above, the heat sealing can be performed by a known method such as bar sealing, rotary roll sealing, belt sealing, impulse sealing, high frequency sealing or ultrasonic sealing.

[0063] Next, the operation of this embodiment having the above-mentioned configuration, that is, the method for recycling the resin body and the method for producing the resin pellets 1 will be described.

[0064] First, resin bodies that are at least 90% or more of the same resin material are collected (collection step, reference symbol S1 in FIG. 7). At this time, the resin bodies may be resin products that have been used on the market, or materials (such as the resin film 5 or laminates 10, 20) that are generated in a resin product manufacturing process before being released to the market. If the resin body is a resin product that has been used on the market, the resin body may be another tube container 40 or packaging bag 70 made from the resin pellets 1. The resin body may also be an item different from the tube container 40, etc. made from the resin pellets 1 (for example, a plastic product collected at a retail store, or plastics sorted by a collection company, etc.).

[0065] Next, the collected resin body is crushed (crushing step, reference symbol S2 in FIG. 7). The resin body may be crushed using, for example, a crusher (shredder), a crushing mill (hammer mill), a grinding machine (grinder), or the like. The resin body may also be crushed into pieces of, for example, about 10 mm x 10 mm in size.

[0066] Next, the crushed resin body is stirred in water to remove foreign matter from the resin body (foreign matter removal step, reference symbol S3 in FIG. 7). This results in resin flakes from which dirt and foreign matter adhering to the resin body have been removed. In the foreign matter removal step, foreign matter may be removed and the resin body may be washed using a washing solution containing an aqueous sodium hydroxide solution or other surfactants. In addition, a decontamination step for removing contaminants may be performed as necessary.

[0067] Next, the resin body (resin flakes) from which the foreign matter has been removed is dried and sorted (drying and sorting step, reference symbol S4 in FIG. 7). At this time, the resin body from which the foreign matter has been removed may be sorted by various sorting methods such as a specific gravity sorting method, a wind sorting method, or an electrostatic sorting method.

[0068] Next, the selected resin body is pulverized (pulverization step, reference symbol S5 in FIG. 7). The resin body may be pulverized using, for example, a pulverizer (shredder), a pulverizing mill (hammer mill), or a grinder (grinder). The resin body may be pulverized to a size of, for example, about 5 mm x 5 mm.

[0069] Next, the pulverized resin body is melted (melting step, reference numeral S6 in FIG. 7). The resin body is melted, for example, in a pellet producing device (not shown).

[0070] Next, the resin pellets 1 are molded from the molten resin body (molding step, reference symbol S7 in FIG. 7). At this time, the molten resin body is first extruded from a filter in a pellet making device (not shown). Then, the extruded resin body is cut into granules. In this way, the resin pellets 1 are molded.

[0071] Thereafter, the resin pellets are cooled (cooling step, reference numeral S8 in FIG. 7).

[0072] In this manner, the resin body is recycled, and resin pellets 1 containing the recycled regenerated resin are obtained.

[0073] Next, a method for producing the laminate 10 will be described.

[0074] For example, when producing the laminate 10 shown in Fig. 3, first, a first resin layer 11 and a second resin layer 12 are prepared. At this time, for example, resin pellets 1 produced by the method shown in Fig. 7 are used as the first resin layer 11 and the second resin layer 12, and a resin film 5 may be produced by, for example, an inflation method.

[0075] Furthermore, the third resin layer 13 is prepared. As the third resin layer 13, for example, a polyethylene film or the like may be used.

[0076] Next, the first resin layer 11, the second resin layer 12 and the third resin layer 13 are laminated together by a dry lamination method, etc. In this manner, the laminate 10 shown in FIG.

[0077] As described above, according to the present embodiment, the method for recycling resin bodies includes a step of recovering resin bodies in which at least 90% or more of the resin body is made of the same resin material, a step of crushing the recovered resin body, a step of removing foreign matter from the resin body by stirring the crushed resin body in water, a step of drying and selecting the resin body from which the foreign matter has been removed, a step of crushing the selected resin body, a step of melting the crushed resin body, a step of forming a resin pellet 1 from the melted resin body, and a step of cooling the resin pellet 1. As a result, the resin pellet 1 contains recycled recycled resin, and the environmental load of the laminates 10, 20, etc. made from the resin pellets 1 can be reduced. Furthermore, in the resin body for making the resin pellets 1, at least 90% or more of the recycled resin is made of the same resin material. As a result, the quality of the laminates 10, 20, etc. made from the resin pellets 1 can be stabilized. Furthermore, since at least 90% or more of the recycled resin is made of the same resin material, the laminates 10, 20, etc. made from the resin pellets 1 can be easily recycled again. EXAMPLES

[0078] Next, a specific example of the above embodiment will be described.

[0079] Example 1 As the first resin layer, a polyethylene film (thickness: 50 μm) was prepared.

[0080] In addition, a milky white high-density polyethylene film (thickness: 25 μm) was prepared as the second resin layer. Next, a print layer was formed on the milky white high-density polyethylene film.

[0081] A multilayer film having a polyethylene layer (thickness 75 μm) and an ethylene-vinyl alcohol copolymer layer (thickness 15 μm) was prepared as the first intermediate layer. A milky white polyethylene film (thickness 50 μm) was prepared as the second intermediate layer. Furthermore, a polyethylene film (thickness 50 μm) was prepared as the third resin layer.

[0082] Next, the first resin layer, the second resin layer, the first intermediate layer, the second intermediate layer, and the third resin layer were laminated together by a co-extrusion lamination method via a polyethylene adhesive resin layer. At this time, the thickness of the adhesive resin layer between the second intermediate layer and the third resin layer was 30 μm, and the thickness of each of the other adhesive resin layers was 20 μm. The layer structure of the obtained laminate is as follows: PE film / printed layer / milky HDPE film / multi-layer PE film / milky PE film / PE film In the above, "PE film" means polyethylene film (hereinafter the same). Also, "milky HDPE film" means milky high-density polyethylene film (hereinafter the same). Also, "multilayer PE film" means multilayer film having a polyethylene layer and an ethylene-vinyl alcohol copolymer layer (hereinafter the same). Also, "milky PE film" means milky polyethylene film (hereinafter the same).

[0083] Next, a tube container shown in Fig. 5 was produced from the obtained laminate. At this time, high density polyethylene (HDPE) was used as the material for the head member. The polyethylene content in the tube container was 95%.

[0084] Example 2 As the first resin layer, a polyethylene film (thickness: 80 μm) was prepared.

[0085] In addition, a high-density polyethylene film (thickness: 25 μm) was prepared as the second resin layer. Next, a print layer was formed on the high-density polyethylene film.

[0086] A multilayer film having a polyethylene layer (thickness 75 μm) and an ethylene-vinyl alcohol copolymer layer (thickness 15 μm) was prepared as an intermediate layer, and a polyethylene film (thickness 100 μm) was prepared as a third resin layer.

[0087] Next, the first resin layer, the second resin layer, the intermediate layer, and the third resin layer were laminated together by a co-extrusion lamination method via a polyethylene adhesive resin layer. At this time, the thickness of the adhesive resin layer between the intermediate layer and the third resin layer was 30 μm, and the thickness of each of the other adhesive resin layers was 20 μm. The layer structure of the obtained laminate is as follows: PE film / HDPE film / printed layer / multi-layer PE film / PE film In the above, "HDPE film" means high density polyethylene film (hereinafter the same).

[0088] Next, a tube container shown in Fig. 5 was produced from the obtained laminate. At this time, high density polyethylene (HDPE) was used as the material for the head member. The polyethylene content in the tube container was 95%.

[0089] Example 3 A polyethylene film (thickness: 75 μm) was prepared as the first resin layer. Next, a print layer was formed on the polyethylene film.

[0090] A polyethylene film (thickness 50 μm) provided with an aluminum vapor deposition film (barrier layer) was prepared as the second resin layer. A multilayer film having a polyethylene layer (thickness 75 μm) and an ethylene-vinyl alcohol copolymer layer (thickness 15 μm) was prepared as the intermediate layer. Furthermore, a polyethylene film (thickness 120 μm) was prepared as the third resin layer.

[0091] Next, the second resin layer, the intermediate layer, and the third resin layer were laminated together by co-extrusion lamination via polyethylene adhesive resin layers, each of which had a thickness of 15 μm.

[0092] Next, the first resin layer was laminated onto the second resin layer, the intermediate layer, and the third resin layer by dry lamination. The layer structure of the obtained laminate is as follows: Printing layer / PE film / aluminum vapor deposition film / PE film / multi-layer PE film / PE film

[0093] Next, a tube container shown in Fig. 5 was produced from the obtained laminate. At this time, high density polyethylene (HDPE) was used as the material for the head member. The polyethylene content in the tube container was 96%.

[0094] (Comparative Example) As the first resin layer, a polyethylene film (thickness: 80 μm) was prepared.

[0095] In addition, a polyethylene terephthalate film (thickness: 12 μm) was prepared as the second resin layer. Next, a print layer was formed on the polyethylene terephthalate film.

[0096] A milky white polyethylene film (thickness 100 μm) was prepared as the first intermediate layer, a polyethylene terephthalate film (thickness 12 μm) provided with a silicon oxide vapor deposition film (barrier layer) was prepared as the second intermediate layer, and a polyethylene film (thickness 80 μm) was prepared as the third resin layer.

[0097] Next, the first resin layer, the second resin layer, and the first intermediate layer were laminated together by a co-extrusion lamination method with a polyethylene adhesive resin layer interposed therebetween. Also, the second intermediate layer and the third resin layer were laminated together by a co-extrusion lamination method with a polyethylene adhesive resin layer interposed therebetween. At this time, the thickness of each adhesive resin layer was set to 25 μm.

[0098] Next, the second intermediate layer and the third resin layer were laminated on the first resin layer, the second resin layer, and the first intermediate layer by dry lamination. The layer structure of the obtained laminate is as follows: PE film / PET film / printed layer / milky PE film / silicon oxide deposition film / PET film / PE film In the above, "PET film" means polyethylene terephthalate film (the same applies below).

[0099] Next, a tube container shown in Fig. 5 was produced from the obtained laminate. At this time, high density polyethylene (HDPE) was used as the material for the head member. The polyethylene content in the tube container was 88%.

[0100] (1) Formability evaluation Next, moldability of the resin pellets was evaluated by producing resin pellets from the tube containers of Example 1 to Comparative Example by the method shown in FIG.

[0101] (2) Appearance evaluation Next, the appearance of the produced resin pellets was observed and evaluated.

[0102] The above results are shown in Table 1.

[0103] [Table 1]

[0104] In the "fluidity" column of Table 1, "good" means that the fluidity of the resin extruded from the filter of the pelletizer was good, while "bad" means that the fluidity of the resin was poor and pellets could not be made.

[0105] In the "Filter clogging" column in Table 1, "good" means that the filter of the pelletizing device was not clogged, and "bad" means that the resin clogged the filter and resin pellets could not be produced.

[0106] In the "strand appearance" column in Table 1, "good" means that the strand extruded in a string shape from the pelletizer had a good appearance, while "bad" means that the resin clogged the filter and no strands could be formed.

[0107] In the "pellet appearance" column in Table 1, "good" means that the resin pellet had a good appearance, and "bad" means that the resin pellet could not be produced.

[0108] As a result, as shown in Table 1, good results were obtained in all items for the tube containers according to Examples 1 to 3. Therefore, it was found that in this embodiment, it is possible to produce resin pellets containing recycled resin and to stabilize the quality of the resin pellets.

[0109] It is also possible to combine the multiple components disclosed in the above embodiments as necessary, or to delete some of the components disclosed in the above embodiments. [Explanation of symbols]

[0110] 1 Resin pellets 5. Resin film 10 Laminate 11 First resin layer 12 Second resin layer 13 Third resin layer 20 Laminate 21 Outer layer 22 Inner layer 40 Tube Container 41 Body tube 42 one end 43 Head parts 70 packaging bags 101 Exterior 102 Inside 201 Exterior 202 Inside

Claims

1. A method for recycling a resin body, comprising the steps of: A step of recovering resin bodies in which at least 90% or more of the resin body is made of a material of the same resin type; Crushing the recovered resin body; removing foreign matter from the resin body by stirring the crushed resin body in water; drying and sorting the resin body from which the foreign matter has been removed; A step of crushing the selected resin body; Melting the pulverized resin body; forming a resin pellet from the molten resin body; and cooling the resin pellets.

2. 2. The method for recycling a resin body according to claim 1, wherein in the step of removing foreign matter from the resin body, the removal of foreign matter and the washing of the resin body are carried out using a washing liquid containing a surfactant.

3. 3. The recycling method according to claim 1, wherein in the step of drying and sorting the resin body, the resin body from which the foreign matter has been removed is sorted by a specific gravity sorting method, a wind sorting method or an electrostatic sorting method.

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