Recycled film manufacturing method, derivation method, and control program

Abstract

To provide a recycled film manufacturing method, a derivation method, and a control program that enable appropriate management of a color of the recycled film.SOLUTION: A recycled film manufacturing method includes the steps of: obtaining recycled raw materials from recovered resin waste; deriving control information for managing a color of the recycled film manufactured using the recycled raw materials; and manufacturing the recycled film based on the control information. The step of deriving the control information includes the steps of: manufacturing multiple film samples with different recycled raw material contents; measuring the color of each of the multiple film samples; and deriving the control information based on results of the color measurements.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for manufacturing a recycled film, a method for extracting the recycled film, and a control program. [Background technology]

[0002] Japanese Patent No. 6849141 (Patent Document 1) discloses a method for producing a heat-shrinkable film. This heat-shrinkable film is produced using a resin composition containing at least one of fluff and re-pellets obtained from packaging material as a starting material. The packaging material, which is the starting material for the fluff and re-pellets, has a printed layer (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6849141 Summary of the Invention [Problem to be solved by the invention]

[0004] Many resin film products have patterns printed on them and contain colorants. Therefore, many resin waste materials, such as film waste, also contain colorants. When recycled film is manufactured using resin waste, the colorants contained in the resin waste affect the color of the recycled film. Depending on the amount of colorants contained in the recycled film, the color of the recycled film may not fall within the acceptable range for commercial use. The above-mentioned Patent Document 1 does not disclose a means for solving such problems.

[0005] The present invention has been made to solve such problems, and its purpose is to provide a manufacturing method, extraction method, and control program for recycled film that can properly manage the color of recycled film. [Means for solving the problem]

[0006] A method for manufacturing a recycled film according to one aspect of the present invention includes the steps of obtaining recycled raw materials from recovered waste resin, deriving control information for managing the color of the recycled film manufactured using the recycled raw materials, and manufacturing the recycled film based on the control information. The step of deriving the control information includes the steps of manufacturing multiple film samples with different recycled raw material contents, measuring the color of each of the multiple film samples, and deriving the control information based on the results of the color measurements.

[0007] In this recycled film manufacturing method, recycled films are manufactured based on the management information. Therefore, according to this recycled film manufacturing method, recycled films are manufactured taking into consideration the relationship between the content of recycled raw materials and the color of the film, so the color of the manufactured recycled film can be appropriately managed.

[0008] In the method for producing the recycled film, the color measurement may be performed by measuring at least one of the L* value, a* value, and b* value in the L*a*b* color space.

[0009] According to this method for producing recycled films, the relationship between the content of recycled raw materials and at least one of the L* value, a* value, and b* value is taken into consideration when producing recycled films, so the color of the recycled films produced can be appropriately controlled.

[0010] In the method for producing the recycled film, color measurement may be performed by further measuring haze.

[0011] According to this method for manufacturing recycled films, recycled films are manufactured taking into consideration the relationship between the content of recycled raw materials and haze, so the degree of haze of the manufactured recycled films can be appropriately controlled.

[0012] In the above-mentioned method for manufacturing recycled film, each of the multiple film samples may contain virgin raw materials and recycled raw materials, and in each of the multiple film samples, when the total weight of the virgin raw materials and recycled raw materials is 100 parts, the weight of the virgin raw materials may be 50 parts or more.

[0013] According to this method for producing recycled films, the weight of the virgin raw material is greater than the weight of the recycled raw material in each of the multiple film samples, so that haze can be measured appropriately for each of the multiple film samples.

[0014] In the above-described method for producing a recycled film, the management information may include a calibration curve showing the relationship between the content of recycled raw materials and the results of measurements related to color.

[0015] According to this method of manufacturing recycled film, recycled film is manufactured taking into consideration a calibration curve showing the relationship between the content of recycled raw materials and the results of color measurements, allowing for appropriate control of the color of the recycled film produced.

[0016] In the above-mentioned method for manufacturing a recycled film, the step of manufacturing the recycled film may include a step of determining the content of recycled raw materials based on a calibration curve, and a step of manufacturing the recycled film so that the content of recycled raw materials in the recycled film is the determined content of recycled raw materials.

[0017] According to this method of manufacturing recycled film, the recycled film is manufactured so that the content of recycled raw materials in the recycled film is the determined content of recycled raw materials, so the color of the recycled film manufactured can be appropriately controlled.

[0018] According to another aspect of the present invention, a method for deriving management information for managing the color of recycled films includes causing a computer to execute a process for deriving management information for managing the color of recycled films. The recycled films are manufactured using recycled materials obtained from recovered waste resin materials. The method includes the steps of causing a computer to execute a process for acquiring color information for each of multiple film samples having different recycled material content rates, and a process for deriving management information based on the color information.

[0019] In this method, management information is derived based on information about the color of each of a plurality of film samples with different recycled material content. Therefore, this method can derive management information that enables appropriate management of the color of recycled film. As a result, this method can appropriately manage the color of recycled film.

[0020] According to another aspect of the present invention, a control program causes a computer to execute a process for deriving management information for managing the color of recycled films. The recycled films are manufactured using recycled materials obtained from recovered waste resin materials. The control program causes the computer to execute a process for acquiring color information for each of multiple film samples having different recycled material content percentages, and a process for deriving management information based on the color information.

[0021] When this control program is executed, management information is derived based on information about the color of each of a plurality of film samples with different recycled material content. Therefore, this control program can derive management information that enables appropriate management of the color of recycled film. As a result, this control program can appropriately manage the color of recycled film. [Effects of the Invention]

[0022] According to the present invention, it is possible to provide a manufacturing method, extraction method, and control program for recycled film that can appropriately manage the color of recycled film. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram illustrating a resource circulation system. [Figure 2] FIG. 1 is a plan view schematically showing an example of a printed film. [Figure 3] FIG. 3 is a diagram schematically showing a cross section taken along line III-III in FIG. 2. [Figure 4] 1 is a flowchart showing an example of a manufacturing procedure for a recycled film. [Figure 5] 5 is a flowchart showing an example of a procedure for pre-processing performed in step S110 of FIG. 4. [Figure 6] 5 is a flowchart showing an example of a procedure for color management processing performed in step S130 of FIG. 4. [Figure 7] FIG. 1 is a diagram schematically showing an example of a calibration curve for a* values. [Figure 8] 5 is a flowchart showing an example of the procedure of the film forming process on the recycled film performed in step S140 of FIG. 4. [Figure 9] FIG. 2 is a diagram schematically illustrating a cross section of an example of a recycled film to be produced. [Figure 10] FIG. 10 is a diagram showing the relationship between the content of recycled raw materials and the a* value of lot No. 1 in the color sheet. [Figure 11] FIG. 10 is a diagram showing the relationship between the content of recycled raw materials and the b* value of lot No. 1 in the color sheet. [Figure 12] FIG. 10 is a diagram showing the relationship between the content of recycled raw materials and the L* value of lot No. 1 in the color sheet. [Figure 13] FIG. 10 is a diagram showing the relationship between the content of recycled raw materials and haze of lot No. 1 in the color sheet. [Figure 14]FIG. 10 is a diagram showing the relationship between the content of recycled raw materials and the a* value of lot No. 2 in the color sheet. [Figure 15] FIG. 10 is a diagram showing the relationship between the content of recycled raw materials and the b* value of lot No. 2 in the color sheet. [Figure 16] FIG. 10 is a diagram showing the relationship between the content of recycled raw materials and the L* value of lot No. 2 in the color sheet. [Figure 17] FIG. 10 is a diagram showing the relationship between the content of recycled raw materials and haze of lot No. 2 in the color sheet. DETAILED DESCRIPTION OF THE INVENTION

[0024] An embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") will be described in detail below with reference to the drawings. Note that the same or corresponding parts in the drawings are designated by the same reference numerals, and their description will not be repeated. Furthermore, for ease of understanding, each drawing is drawn schematically with objects appropriately omitted or exaggerated.

[0025] [1. Overview] In recent years, marine pollution caused by plastic waste has become a global problem, and resource recycling has been attracting attention as a means of addressing this issue.

[0026] FIG. 1 is a schematic diagram illustrating a resource circulation system S1 that uses a recycled film manufacturing method according to the present embodiment. Referring to FIG. 1, in the resource circulation system S1, for example, a resin film printed with a design (hereinafter also referred to as "printed film") is recycled to produce a new film. The design may be, for example, a pattern, letters, a symbol (e.g., a barcode), or a combination thereof. The printed film may be, for example, a heat-shrinkable film or a packaging bag that can be used for food, beverages, pharmaceuticals, medical supplies, cosmetics, toiletries, or industrial and agricultural products. The resource circulation target in the resource circulation system S1 does not necessarily have to be printed film. For example, it may be a resin film without a printed design, a resin container with a printed design, a resin container without a printed design, or a container with a printed film attached. In other words, the waste material recycled in the resource circulation system S1 is resin waste, and this includes film waste and resin containers. The following describes the recycling of film waste, a typical resin waste material.

[0027] FIG. 2 is a plan view schematically illustrating an example of a printed film. In this example, the printed film 10 is a heat-shrinkable film before heat shrinking. As shown in FIG. 2, the printed film 10 includes a product portion 100 and edge portions 110A and 110B. The edge portions 110 are located adjacent to both ends of the product portion 100 in the width direction. A design is printed on each of the product portion 100 and the edge portions 110. Hereinafter, the design printed on the product portion 100 will also be referred to as the "product portion design," and the design printed on the edge portion 110 will also be referred to as the "edge portion design." The ratio of the area of ​​the edge portion design to the area of ​​the edge portion 110 is 70% or less, preferably 50% or less, more preferably 30% or less, and even more preferably 15% or less. The ratio of the area of ​​the ear portion pattern to the area of ​​the ear portion 110 is smaller than the ratio of the area of ​​the product portion pattern to the area of ​​the product portion 100.

[0028] The product portion 100 is used to package plastic containers, glass containers, paper containers, etc. For example, much of the waste film collected through the market is heat-shrunk product portion 100. Each of the edge portions 110A, 110B is printed with information for checking the printing status of the product portion 100. That is, the edge portions 110 are used to check the printing status of the product portion 100. The edge portions 110 are cut off before the product portion 100 is shipped, and become waste film. The edge portion 110A is printed with a registration mark 112A and a color control mark 116. The edge portion 110B is printed with a registration mark 112B, a slit line 114, and a color bar 118.

[0029] Printing on the film is performed, for example, using a gravure plate. Registration marks 112 are used to align the gravure plate when printing the design. Slit lines 114 are used when cutting the edge portions 110 from the printed film 10. Color control marks 116 are composed of multiple triangles and are used to align the color plates. The color control marks 116 include a triangle for each color used in printing. Color bars 118 are used to check the quality of the density of each printed color.

[0030] Figure 3 is a schematic diagram showing the cross section taken along line III-III in Figure 2. As shown in Figure 3, the printed film 10 includes a resin layer 12 and a printing layer 14. The printing layer 14 is composed of a coloring component (colorant) such as ink that forms a pattern. In this example, the object to be packaged is placed on the printing layer 14 side. That is, when packaging is performed using the printed film 10, the printing layer 14 is located on the inside. An inner coat layer may be provided on the printing layer 14, and an overcoat layer may be provided on the resin layer 12.

[0031] The resin layer 12 may be composed of a single layer or multiple laminated layers. The resin layer 12 may include a layer containing a mixture of different types of resins, or multiple layers each containing a different type of resin. Each layer constituting the resin layer 12 may contain components other than resin. Each layer may contain metal components such as aluminum, antiblocking agents, additives, etc. Examples of additives include heat stabilizers, antioxidants, UV absorbers, light stabilizers, lubricants, antistatic agents, flame retardants, antibacterial agents, and fluorescent brighteners.

[0032] Examples of the resin contained in each layer include polyolefin-based resins, polystyrene-based resins, polyamide-based resins, and polyester-based resins. Examples of polyolefin-based resins include polypropylene-based, polyethylene-based, and cyclic polyolefin-based resins. Examples of polypropylene-based resins include binary or ternary random copolymers containing propylene as the main component and ethylene, butene, or an α-olefin as a copolymerization component. Specific examples of α-olefins include those composed of ethylene, 1-butene, 1-hexene, 1-octene, etc., and may contain two or more types of α-olefins. Furthermore, the polypropylene-based resin may be a mixture of different propylene-α-olefin random copolymers. Examples of polyethylene-based resins include branched low-density polyethylene resins, linear low-density polyethylene resins, high-density polyethylene resins, ethylene-vinyl acetate copolymers, ionomer resins, and mixtures thereof. Furthermore, copolymers of ethylene and α-olefins may be used. Examples of α-olefins include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene. The copolymer may be a random copolymer or a block copolymer. Examples of cyclic olefin resins include (a) copolymers of ethylene or propylene with cyclic olefins (e.g., norbornene and its derivatives, tetracyclododecene and its derivatives, etc.), (b) ring-opening polymers of the cyclic olefins or copolymers with α-olefins, (c) hydrogenated products of the polymers (b), and (d) graft-modified products of the above (a) to (c) with unsaturated carboxylic acids and their derivatives, etc. The cyclic olefin is not particularly limited, and specific examples thereof include norbornene, 6-methylnorbornene, 6-ethylnorbornene, 5-propylnorbornene, 6-n-butylnorbornene, 1-methylnorbornene, 7-methylnorbornene, 5,6-dimethylnorbornene, 5-phenylnorbornene, and 5-benzylnorbornene.Examples of polystyrene-based resins include styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-isoprene-butadiene copolymers, styrene-acrylic copolymers, acrylonitrile-butadiene-styrene copolymers, and acrylonitrile-styrene copolymers. Examples of polyamide-based resins include aliphatic polyamides, aromatic polyamides, amorphous polyamides, and polyamide elastomers. Examples of the aliphatic polyamide include aliphatic nylon and its copolymers, such as polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecaneamide (nylon-11), polylauryllactam (nylon-12), polyethylenediamineadipamide (nylon-2,6), polytetramethyleneadipamide (nylon-4,6), polyhexamethyleneadipamide (nylon-6,6), polyhexamethylenesebacamide (nylon-6,10), polyhexamethylenedodecamide (nylon-6,12), polyoctamethyleneadipamide (nylon-8,6), and polydecamethyleneadipamide (nylon-10,8). Examples of polyester resins include those obtained by condensation polymerization of a dicarboxylic acid component and a diol component. The type of the dicarboxylic acid component is not particularly limited, and examples include terephthalic acid, o-phthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octylsuccinic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, decamethylenecarboxylic acid, anhydrides thereof, and lower alkyl esters thereof.The type of the diol component is not particularly limited, and examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5- Examples include aliphatic diols such as hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, and polytetramethylene ether glycol; and alicyclic diols such as 2,2-bis(4-hydroxycyclohexyl)propane, alkylene oxide adducts of 2,2-bis(4-hydroxycyclohexyl)propane, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol.

[0033] Referring back to FIG. 1 , the resource circulation system S1 includes a pretreatment device D1, a resin raw material manufacturing device D2, a color management device D3, and a film manufacturing device D4. The pretreatment device D1 is configured to pretreat waste film collected from the market or factories. For example, the pretreatment device D1 performs foreign matter removal, material sorting, pulverization, and ink removal on the waste film. Details of each process will be explained later. The resin raw material manufacturing device D2 is configured to manufacture resin raw material using the pretreated waste film. Most waste film contains colorants. Therefore, when resin raw material manufactured from waste film is used to manufacture recycled film, the colorants contained in the waste film affect the color of the recycled film. From the perspective of promoting recycling, it is preferable to use a large amount of waste film as the raw material for recycled film. However, depending on the amount of colorants contained in the recycled film, the color of the recycled film may not be within the acceptable range for commercial use. The color management device D3 performs processing to manage the color of the recycled film so that the color of the recycled film falls within an acceptable range, as will be described in detail later. The film manufacturing device D4 is configured to manufacture recycled film using the resin raw material manufactured by the resin raw material manufacturing device D2 and taking into account the processing results of the color management device D3.

[0034] For example, the recycled film produced by the film production device D4 is printed again. That is, the printed film 10 is produced again. The product portion 100 of the produced printed film 10 is, for example, shipped and then collected again from the market. In addition, the edge portion 110 of the produced printed film 10 is, for example, cut off at a factory and then collected again. The collected product portion 100 and edge portion 110 are each used to produce new film. Resource circulation is achieved by repeating this cycle.

[0035] In this way, the resource circulation system S1 manages the color of recycled films, thereby preventing the production of recycled films whose color does not fall within the acceptable range for commercial products.

[0036] [2.Recycled film manufacturing procedure] FIG. 4 is a flowchart showing an example of a manufacturing procedure for recycled film. Referring to FIG. 4, first, waste film is collected (step S100). The waste film may be collected from the market or from a factory or the like. That is, the waste film may be PIR (Post Industrial Recycle) material or PCR (Post Consumer Recycle) material. The waste film may include various types of film with various types of printing. Note that the waste film does not necessarily have to include various types of film with various types of printing, and may include, for example, only one type of film. For example, only one specific type of film may be recycled as waste film from waste material collected from a factory or the like. The collected waste film is subjected to pre-processing (step S110).

[0037] Fig. 5 is a flowchart showing an example of the procedure of preprocessing performed in step S110 of Fig. 4. Each step shown in this flowchart is performed, for example, by a preprocessing device D1. The preprocessing device D1 may be configured by one device or may be configured by multiple devices. The preprocessing device D1 is realized, for example, by various known devices having each function.

[0038] Referring to FIG. 5, foreign matter removal is performed on the collected waste film (step S200). In step S200, foreign matter mixed in or attached to the collected waste film is removed. Methods for removing foreign matter include, for example, a method of removing metallic foreign matter using a metal detector, a method of separating foreign matter by utilizing the difference in specific gravity between the foreign matter and resin (specific gravity separation), a method of separating foreign matter by using wind power (winnowing separation), and a method of removing foreign matter attached to the surface of the film using water, detergent, chemical solution, etc. (washing). Removing foreign matter in step S200 can prevent equipment failure in subsequent processes and a decrease in the strength of the recycled film.

[0039] The collected film waste is subjected to material sorting (step S210). Methods for material sorting include, for example, a method of sorting materials using a near-infrared spectroscopic sensor, and a method of separating materials by utilizing differences in specific gravity between materials. For example, the desired materials obtained through material sorting are used to produce recycled raw materials. By performing material sorting in step S210, the purity of the recycled raw materials produced can be increased, and deterioration in the quality of the recycled film can be suppressed.

[0040] The collected waste film is subjected to a crushing process (step S220). In step S220, the waste film is crushed to a desired size. Either dry crushing or wet crushing may be used to crush the waste film. By adjusting the size of the waste film in step S220, the processing efficiency in subsequent processes is adjusted. For example, the smaller the size of the crushed waste film, the higher the loading rate of the waste film into the device in the ink removal process (deinking process) described below, thereby improving processing efficiency. Furthermore, for example, when melt granulation is performed in the granulation process described below, the smaller the size of the crushed waste film, the less likely it is that the waste film will be poorly engaged with the screw, thereby improving processing efficiency. Furthermore, for example, when the ink layer is removed by rubbing the printed surface in the ink removal process, the larger the size of the crushed waste film, the larger the area of ​​the scrap film that is rubbed against it, thereby improving processing efficiency.

[0041] The recovered waste film undergoes an ink removal process (deinking process) (step S230). In step S230, the printed layer is removed from the waste film. Methods for removing the printed layer include, for example, chemical removal and physical removal. In chemical removal, the waste film is immersed in a release agent, and the printed layer is peeled off or dissolved using a chemical reaction caused by the release agent. The release agent may contain, for example, an alkaline component, an alcoholic component, or a surfactant. Examples of alkaline components include inorganic hydroxides such as sodium hydroxide and calcium hydroxide, and amine compounds. Examples of alcoholic components include monohydric alcohols such as methanol, ethanol, isopropyl alcohol, and benzyl alcohol, as well as glycol-based alcohols. Examples of surfactants include neutral, cationic, anionic, and nonionic surfactants. In physical removal, the printed layer is removed by mechanical actions such as rubbing, scraping, or peeling. In step S230, for example, at least one of chemical removal and physical removal may be used, or both chemical removal and physical removal may be used. The ink removal process may not be performed, for example, if the majority of the recovered film waste is the edge portion 110. By performing the ink removal process in step S230 and producing recycled raw materials from the film waste after the ink removal process, more recycled raw materials can be used to produce recycled film.

[0042] Referring again to FIG. 4, when the pretreatment is completed in step S110, the pretreated waste film is granulated to produce recycled raw material (step S120). Step S120 is performed, for example, by a resin raw material manufacturing apparatus D2. The resin raw material manufacturing apparatus D2 can be realized, for example, by various known devices capable of granulating waste film. In step S120, the pretreated waste film is processed into granules. Examples of granulation methods include melt granulation and compression granulation. In melt granulation, the melt-kneaded waste film is extruded, and the extruded waste film is water-cooled and cut at the die outlet, thereby processing the waste film into granules. In compression granulation, the waste film is compression-molded to process the waste film into granules. In step S120, additives (e.g., heat stabilizers, antioxidants, UV absorbers, light stabilizers, lubricants, antistatic agents, flame retardants, antibacterial agents, fluorescent brighteners, virgin raw materials, antiblocking agents) may be added to the waste film. Granulation in step S120 increases the bulk density of the waste film, thereby reducing the space required for storage of the waste film. Once the recycled raw material is produced in step S120, processing is performed to manage the color of the recycled film (step S130).

[0043] FIG. 6 is a flowchart showing an example of the procedure for the color management process performed in step S130 of FIG. 4. Referring to FIG. 6, a plurality of film samples are produced (step S300). This process is performed, for example, by a film manufacturing apparatus D4. The film manufacturing apparatus D4 may be realized by various known apparatuses capable of producing films by extrusion molding, for example. In the film manufacturing apparatus D4, a laminated film is produced, for example, by co-extrusion.

[0044] Each of the multiple film samples is manufactured using a resin raw material that is a mixture of granular recycled raw materials and virgin raw materials. In this resin raw material, it is preferable that the weight of the virgin raw material is 50 parts or more when the total weight of the recycled raw materials and virgin raw materials is 100 parts. Furthermore, when the recycled film 20 described below is manufactured using the recycled raw materials, it is preferable that the virgin raw material is the same as the virgin raw material contained in the intermediate layer 22 of the recycled film 20 described below, or a virgin raw material of the same type that is close in color to the virgin raw material contained in the intermediate layer 22. When the recycled film 20 described below is manufactured using the recycled raw materials, it is preferable that the layer structure of each of the multiple film samples is the same as the layer structure of the recycled film 20. The recycled raw material content of the resin raw material differs among the multiple film samples.

[0045] After the multiple film samples are manufactured, the color of each film sample is measured (step S310). This step is performed by, for example, a color management device D3. The color management device D3 includes, for example, a computer and a color measurement device. The color measurement device is configured to measure, for example, each of the L* value, a* value, and b* value in the L*a*b* color space. The color measurement device is also configured to measure haze. The color measurement device may be configured as a single device or as a plurality of devices. Various known devices can be used as the color measurement device. In step S310, the L* value, a* value, b* value, and haze of each film sample are measured.

[0046] After the L* value, a* value, b* value, and haze of each film sample are measured, calibration curves (an example of "management information") for the L* value, a* value, b* value, and haze are derived (step S320). This process is performed, for example, by a computer in the color management device D3. Specifically, this process is performed by a CPU (Central Processing Unit) included in the computer acquiring information about the measured L* value, a* value, b* value, and haze, and executing a control program stored in a memory included in the computer.

[0047] FIG. 7 is a diagram showing an example of a calibration curve for the a* value. Referring to FIG. 7, the horizontal axis indicates the content of recycled materials in the resin raw material, and the vertical axis indicates the a* value. In this example, three film samples are produced in step S300. In FIG. 7, the a* value of each film is plotted. The calibration curve L1 is an approximate straight line obtained from the three plots. The computer of the color management device D3 derives the calibration curve L1 from the multiple plots.

[0048] Referring again to FIG. 4, once the calibration curves for the L* value, a* value, b* value, and haze are derived in step S130, a film-forming process for a recycled film is performed (step S140).

[0049] FIG. 8 is a flowchart showing an example of the procedure for the film formation process for recycled films performed in step S140 of FIG. 4. Referring to FIG. 8, the content of recycled materials in the resin raw material used for the recycled film is determined by referencing calibration curves for the L* value, a* value, b* value, and haze (step S400). Specifically, the content of recycled materials in the resin raw material is determined so that the L* value, a* value, b* value, and haze of the recycled film fall within desired ranges. This step is performed by a CPU included in a computer that references information on the desired ranges for the L* value, a* value, b* value, and haze, as well as the derived calibration curves, and executes a control program stored in a memory included in the computer.

[0050] A resin raw material is prepared in which the content of recycled raw materials has been adjusted to the content determined in step S400 (step S410). A recycled film is produced using the prepared resin raw material (step S420). This step is performed, for example, by film production apparatus D4. As a result, the color of the produced recycled film is adjusted to a desired range. The resin raw material used to produce the recycled film may also include other biomass-derived materials or chemically recycled materials.

[0051] [3. Examples of recycled film] FIG. 9 is a schematic diagram showing a cross section of an example of a manufactured recycled film. As shown in FIG. 9, the recycled film 20 includes an intermediate layer 22 and adjacent layers 21 and 23. In the recycled film 20, the intermediate layer 22 is sandwiched between the adjacent layers 21 and 23. In the recycled film 20, the intermediate layer 22 is made of a resin material containing virgin materials and recycled materials. Each of the adjacent layers 21 and 23 is made of virgin materials. Each of the adjacent layers 21 and 23 does not contain recycled materials. An adhesive layer may be provided between the intermediate layer 22 and the adjacent layers 21 and 23.

[0052] Examples of resins constituting the virgin raw materials contained in each layer include polyolefin-based resins, polystyrene-based resins, polyamide-based resins, and polyester-based resins. Examples of polyolefin-based resins include polypropylene-based, polyethylene-based, and cyclic polyolefin-based resins. Examples of polypropylene-based resins include binary or ternary random copolymers containing propylene as the main component and ethylene, butene, or an α-olefin as a copolymerization component. Specific examples of α-olefins include those composed of ethylene, 1-butene, 1-hexene, 1-octene, etc., and may contain two or more types of α-olefins. Furthermore, polypropylene-based resins may be mixtures of different propylene-α-olefin random copolymers. Examples of polyethylene-based resins include branched low-density polyethylene resins, linear low-density polyethylene resins, high-density polyethylene resins, ethylene-vinyl acetate copolymers, ionomer resins, and mixtures thereof. Furthermore, copolymers of ethylene and α-olefins may be used. Examples of α-olefins include 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, and 1-octene. The copolymer may be a random copolymer or a block copolymer. Examples of cyclic olefin resins include (a) copolymers of ethylene or propylene with cyclic olefins (e.g., norbornene and its derivatives, tetracyclododecene and its derivatives, etc.), (b) ring-opening polymers of the cyclic olefins or copolymers with α-olefins, (c) hydrogenated products of the polymers (b), and (d) graft-modified products of the above (a) to (c) with unsaturated carboxylic acids and their derivatives, etc. The cyclic olefin is not particularly limited, and specific examples thereof include norbornene, 6-methylnorbornene, 6-ethylnorbornene, 5-propylnorbornene, 6-n-butylnorbornene, 1-methylnorbornene, 7-methylnorbornene, 5,6-dimethylnorbornene, 5-phenylnorbornene, and 5-benzylnorbornene.Examples of polystyrene-based resins include styrene-butadiene copolymers, styrene-isoprene copolymers, styrene-isoprene-butadiene copolymers, styrene-acrylic copolymers, acrylonitrile-butadiene-styrene copolymers, and acrylonitrile-styrene copolymers. Examples of polyamide-based resins include aliphatic polyamides, aromatic polyamides, amorphous polyamides, and polyamide elastomers. Examples of the aliphatic polyamide include aliphatic nylon and its copolymers, such as polycapramide (nylon-6), poly-ω-aminoheptanoic acid (nylon-7), poly-ω-aminononanoic acid (nylon-9), polyundecaneamide (nylon-11), polylauryllactam (nylon-12), polyethylenediamineadipamide (nylon-2,6), polytetramethyleneadipamide (nylon-4,6), polyhexamethyleneadipamide (nylon-6,6), polyhexamethylenesebacamide (nylon-6,10), polyhexamethylenedodecamide (nylon-6,12), polyoctamethyleneadipamide (nylon-8,6), and polydecamethyleneadipamide (nylon-10,8). Examples of polyester resins include those obtained by condensation polymerization of a dicarboxylic acid component and a diol component. The type of the dicarboxylic acid component is not particularly limited, and examples include terephthalic acid, o-phthalic acid, isophthalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, octylsuccinic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, fumaric acid, maleic acid, itaconic acid, decamethylenecarboxylic acid, anhydrides thereof, and lower alkyl esters thereof.The type of the diol component is not particularly limited, and examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-butanediol, 2,3-butanediol, neopentyl glycol (2,2-dimethylpropane-1,3-diol), 1,2-hexanediol, 2,5- Examples include aliphatic diols such as hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, and polytetramethylene ether glycol; and alicyclic diols such as 2,2-bis(4-hydroxycyclohexyl)propane, alkylene oxide adducts of 2,2-bis(4-hydroxycyclohexyl)propane, 1,4-cyclohexanediol, and 1,4-cyclohexanedimethanol.

[0053] [4. Features] As described above, in the resource circulation system S1 according to the present embodiment, recycled films are produced based on a calibration curve that has been derived in advance. Therefore, the resource circulation system S1 produces recycled films taking into consideration the relationship between the content of recycled raw materials and the color of the recycled films, and therefore the color of the recycled films produced can be appropriately managed.

[0054] Furthermore, according to the resource circulation system S1 of this embodiment, recycled film is produced taking into consideration the relationship between the content of recycled raw materials and at least one of the L* value, a* value, and b* value, so that the color of the recycled film produced can be appropriately managed.

[0055] Furthermore, according to the resource circulation system S1 of this embodiment, recycled films are produced taking into consideration the relationship between the content of recycled raw materials and haze, so the degree of haze of the recycled films produced can be appropriately managed.

[0056] Furthermore, according to the resource circulation system S1 of the present embodiment, the weight of the virgin raw material is greater than the weight of the recycled raw material in each of the multiple film samples, so that haze measurements can be performed appropriately for each of the multiple film samples.

[0057] Furthermore, according to the resource circulation system S1 of this embodiment, the recycled film is manufactured so that the content of recycled raw materials in the recycled film is determined by referring to a calibration curve, and therefore the color of the recycled film manufactured can be appropriately managed.

[0058] [5. Experimental Example] <5-1. Various film samples> Film samples 1-9 were produced by coextrusion using an extruder. Film samples 1-4 were produced using a resin material (Lot No. 1) containing recycled and virgin raw materials manufactured using the product portion 100 of printed film 10. Film samples 5-9 were produced using a resin material (Lot No. 2) containing recycled and virgin raw materials manufactured using the edge portion 110 of printed film 10. Ink removal was performed during the manufacturing process for recycled raw materials using the product portion 100, while ink removal was not performed during the manufacturing process for recycled raw materials using the edge portion 110. Each film sample had a layer structure of adjacent layer / middle layer / adjacent layer. The resin material containing recycled raw materials was used for the middle layer. The recycled raw material content, film structure, and thickness of each film sample were as shown in Table 1 below. In Table 1, "PS" represents polystyrene-based resin and "PET" represents polyester-based resin. Films (sheets) corresponding to the middle layer of each film sample were also produced separately.

[0059] [Table 1]

[0060] <5-2. Various evaluations> (5-2-1. Color) The film (sheet) corresponding to the intermediate layer of each obtained film sample and each obtained film sample were cut into samples measuring MD 100 mm x TD 100 mm, and the L*, a*, and b* values ​​expressed in the L*a*b* color system were measured using a color difference meter (Spectrophotometer CM-600d manufactured by Konica Minolta Japan Inc.) (N=10), and the average values ​​were calculated.

[0061] (5-2-2. Hayes) The haze value was measured using a haze meter (NDH5000, manufactured by Nippon Denshoku Industries Co., Ltd.) at a temperature of 23°C according to a method in accordance with JIS Z7136. The haze value was measured for the film (sheet) corresponding to the intermediate layer of each film sample and for each of the obtained film samples at shrinkage rates of 0%, 10%, and 20%. The haze value was measured using four samples, and the average value was calculated. <5-3. Evaluation Results> The results of the various measurements are shown in Table 2 below.

[0062] [Table 2]

[0063] The "Color Sheet" item in Table 2 shows the results of color measurement of a single-layer film (single-layer configuration with an intermediate layer (including recycled materials) shown in Table 1). The "Haze Sheet" item in Table 2 shows the results of haze measurement of a single-layer film (single-layer configuration with an intermediate layer (including recycled materials) shown in Table 1). The "Color Film" item in Table 2 shows the results of color measurement of a laminated film (lamination configuration (adjacent layer / intermediate layer / adjacent layer) shown in Table 1). The "Haze Film" item in Table 2 shows the results of haze measurement of a laminated film (lamination configuration (adjacent layer / intermediate layer / adjacent layer) shown in Table 1).

[0064] FIG. 10 is a diagram showing the relationship between the recycled material content of lot No. 1 and the a* value in the color sheet. FIG. 11 is a diagram showing the relationship between the recycled material content of lot No. 1 and the b* value in the color sheet. FIG. 12 is a diagram showing the relationship between the recycled material content of lot No. 1 and the L* value in the color sheet. FIG. 13 is a diagram showing the relationship between the recycled material content of lot No. 1 and the haze in the color sheet. FIG. 14 is a diagram showing the relationship between the recycled material content of lot No. 2 and the a* value in the color sheet. FIG. 15 is a diagram showing the relationship between the recycled material content of lot No. 2 and the b* value in the color sheet. FIG. 16 is a diagram showing the relationship between the recycled material content of lot No. 2 and the L* value in the color sheet. FIG. 17 is a diagram showing the relationship between the recycled material content of lot No. 2 and the haze in the color sheet.

[0065] 10-17, it can be seen that there is a strong correlation between the recycled material content and the L* value, a* value, b* value, and haze for each of Lots 1 and 2. In other words, it can be seen that by deriving a calibration curve in advance, recycled film of the desired color can be produced.

[0066] 6. Other Embodiments The concept of the above embodiment is not limited to the embodiment described above. An example of another embodiment to which the concept of the above embodiment can be applied will be described below.

[0067] <6-1> In the above embodiment, some of the steps S200-S230 shown in Fig. 5 may not be performed. Furthermore, steps S200-S230 may be performed in any order. Furthermore, in addition to steps S200-S230, color sorting of the waste film may be performed. For example, a method of sorting based on images captured by a camera may be used as the color sorting method.

[0068] <6-2> In the above embodiment, the pre-treated film waste does not necessarily have to be granulated, in which case the pre-treated film waste may be used as a recycled raw material.

[0069] <6-3> In the above embodiment, each of the multiple film samples manufactured to derive the calibration curve does not necessarily have to be a laminate film. Each of the multiple film samples manufactured to derive the calibration curve may be a monolayer film. The L* value, a* value, b* value, and haze of the laminate film may be estimated from the L* value, a* value, b* value, and haze of the monolayer film, respectively. In this case, the relationship between the L* value, a* value, b* value, and haze of the monolayer film and the L* value, a* value, b* value, and haze of the laminate film may be investigated in advance through experiments, and the L* value, a* value, b* value, and haze of the laminate film may be estimated based on the investigation results.

[0070] <6-4> In the above embodiments, the parameters measured regarding color do not necessarily have to be the L* value, the a* value, and the b* value. The parameters measured regarding color may be, for example, the L* value, the C* value, and the h value in the L*C*h space. Furthermore, in the above embodiments, it is not necessary to measure each of the L* value, the a* value, and the b* value; it is sufficient to measure at least one of the L* value, the a* value, and the b* value. Furthermore, in the above embodiments, it is not necessary to measure haze. When only one of the L* value, the a* value, and the b* value is measured, it is less of a problem if, for example, the weight of virgin raw material in the resin raw material used to manufacture multiple film samples is less than 50 parts (the weight of recycled raw material is 50 parts or more).

[0071] The above describes exemplary embodiments of the present invention. That is, the detailed description and the accompanying drawings are disclosed for the purpose of illustrative explanation. Therefore, some of the components described in the detailed description and the accompanying drawings may be non-essential components for solving the problems. Therefore, just because these non-essential components are described in the detailed description and the accompanying drawings, it should not be immediately recognized that these non-essential components are essential.

[0072] Furthermore, the above-described embodiment is merely an example of the present invention in all respects. Various improvements and modifications can be made to the above-described embodiment within the scope of the present invention. In other words, when implementing the present invention, specific configurations can be appropriately adopted depending on the embodiment. [Explanation of symbols]

[0073] 10 printed film, 12 resin layer, 14 printing layer, 20 recycled film, 21, 23 adjacent layers, 22 intermediate layer, 100 product part, 110 edge part, 112 registration mark, 114 slit line, 116 color control mark, 118 color bar, D1 pretreatment device, D2 resin raw material manufacturing device, D3 color management device, D4 ​​film manufacturing device, L1 calibration curve, S1 resource circulation system.

Claims

1. Obtaining recycled raw materials based on the recovered resin waste; deriving management information for managing the color of recycled films produced using the recycled raw materials; and manufacturing the recycled film based on the management information, deriving the management information producing a plurality of film samples with different recycled content; making color measurements on each of the plurality of film samples; and deriving the control information based on the results of the color measurements.

2. 2. The method for producing a recycled film according to claim 1, wherein the color measurement is performed by measuring at least one of the L* value, the a* value, and the b* value in the L*a*b* color space.

3. The method for producing recycled film according to claim 2 , wherein the color measurement is performed by further measuring haze.

4. each of the plurality of film samples comprises virgin material and the recycled material; 4. The method for producing recycled film according to claim 3, wherein in each of the plurality of film samples, the weight of the virgin raw material is 50 parts or more when the total weight of the virgin raw material and the recycled raw material is 100 parts.

5. The method for producing a recycled film according to claim 1 , wherein the management information includes a calibration curve showing the relationship between the content of the recycled raw material and the result of the measurement regarding the color.

6. The step of producing the recycled film includes: determining the content of the recycled raw material based on the calibration curve; The method for producing a recycled film according to claim 5, further comprising the step of producing the recycled film so that the content of the recycled material in the recycled film is the determined content of the recycled material.

7. A method for causing a computer to execute a process for deriving management information for managing the color of recycled film, the method comprising: The recycled film is produced by using recycled raw materials obtained from recovered resin waste materials, acquiring color information for each of the plurality of film samples with different recycled content percentages; and deriving the management information based on the information about the color.

8. A control program for causing a computer to execute a process for deriving management information for managing the color of recycled film, comprising: The recycled film is produced by using recycled raw materials obtained from recovered resin waste materials, acquiring color information for each of the plurality of film samples with different recycled content percentages; and deriving the management information based on the information about the color.

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