Recycling methods for used PET film, pellets, and resin molded products

Abstract

This makes it possible to further expand the uses of used PET film by recycling it with ceramics attached to its surface. [Solution] The method for recycling used PET film includes the steps of mechanically removing ceramics adhering to the surface of the used PET film (step S2), cleaning the surface of the used PET film from which the ceramics have been removed (step S3), processing the used PET film with the cleaned surface into flakes (step S4), processing the flakes into first pellets (step S5), adding an additive to the first pellets (step S6), processing the first pellets with the additive added into second pellets (step S7), and molding a resin molded product using the second pellets (step S8), and adding an additive to the first pellets to adjust the IV value of the second pellets to a value within a predetermined range.

Description

[Technical Field]

[0001] The present invention relates to a method for recycling used PET film, pellets, and resin molded articles, and more particularly to a method for recycling used PET film having ceramics attached to its surface, pellets, and resin molded articles. [Background technology]

[0002] In recent years, there has been a demand for the reuse of materials as a measure to conserve environmental resources. For example, PET film is used as a carrier film in the intermediate process of manufacturing multilayer electronic components such as multilayer ceramic capacitors, and there is a demand for the reuse of used PET film as well. For example, Patent Document 1 discloses a method for recycling used PET film, in which foreign matter adhering to the surface of the PET film is washed with a cleaning solution containing an organic solvent, and the cleaning solution adhering to the surface of the PET film is removed, thereby converting the used PET film into new PET film for recycling. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-291690 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the method for recycling used PET film disclosed in Patent Document 1 is limited to recycling used PET film into new PET film, and the applications in which used PET film can be reused are limited.

[0005] The present invention has been made in view of the above circumstances, and has an object to make it possible to further expand the uses of used PET film having ceramics attached to its surface by recycling it. [Means for solving the problem]

[0006] A method for recycling used PET film according to one aspect of the present invention is a method for recycling used PET film having ceramics attached to its surface, the method comprising: a removal step of mechanically removing the ceramics attached to the surface of the used PET film from the used PET film; a flake processing step of processing the used PET film after the ceramics attached to the surface have been removed in the removal step into flakes; a first pellet processing step of processing the flakes produced in the flake processing step into first pellets; an addition step of adding an additive to the first pellets produced in the first pellet processing step; a second pellet processing step of processing the first pellets to which the additive has been added in the addition step into second pellets; and a molding step of molding a resin molded product using the second pellets processed in the second pellet processing step, wherein in the addition step, the additive is added to the first pellets to adjust the IV value of the second pellets to a value within a predetermined range.

[0007] Pellets according to one aspect of the present invention are pellets produced using used PET film having ceramics attached to its surface, the ceramics attached to the surface of the used PET film being mechanically removed from the used PET film, the used PET film from which the ceramics attached to the surface have been removed being processed into flakes, the flakes being processed into first pellets, an additive being added to the first pellets to adjust the IV value of the pellets to a value within a predetermined range, and the first pellets to which the additive has been added being processed to produce pellets.

[0008] A resin molded article according to one aspect of the present invention is a resin molded article molded using the above-described pellets.

[0009] Another aspect of the present invention relates to a method for recycling used PET film having ceramics attached to its surface, and the method includes the steps of: a removal step of mechanically removing the ceramics attached to the surface of the used PET film from the used PET film; a flake processing step of processing the used PET film after the ceramics attached to the surface have been removed in the removal step into flakes; an addition step of adding an additive to the flakes produced in the flake processing step; a pellet processing step of processing the flakes to which the additive has been added in the addition step into pellets; and a molding step of molding a resin molded product using the pellets processed in the pellet processing step, wherein in the addition step, the additive is added to the flakes to adjust the IV value of the pellets to a value within a predetermined range.

[0010] Another aspect of the present invention provides pellets manufactured using used PET film having ceramics attached to its surface, the ceramics attached to the surface of the used PET film being mechanically removed from the used PET film, the used PET film from which the ceramics attached to the surface have been removed being processed into flakes, an additive being added to the flakes to adjust the IV value of the pellets to a value within a predetermined range, and the flakes to which the additive has been added being processed to manufacture the pellets.

[0011] A resin molded article according to another aspect of the present invention is a resin molded article molded using the above-described pellets. [Effects of the Invention]

[0012] According to the present invention, by adding an additive to the first pellets or flakes so that the IV value of the second pellets or pellets used to form a resin molded product falls within a predetermined range, the uses of recycled PET film can be expanded to include resin molded products, rather than just as new PET film. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram showing an outline of a manufacturing process for a multilayer ceramic capacitor, illustrating that ceramics are attached to the surface of a used PET film used in a method for recycling a used PET film according to a first embodiment of the present invention. [Figure 2] 1A to 1C are diagrams illustrating steps in a method for recycling used PET films according to a first embodiment. [Figure 3] 3 is a diagram showing an outline of products etc. in the process of the method for recycling used PET film shown in FIG. 2. [Figure 4] 3 is an explanatory diagram for explaining the mechanism for removing ceramics adhered to the surface from a used PET film in the ceramic removal step of FIG. 2. FIG. [Figure 5] 10A to 10C are diagrams showing steps of a method for recycling used PET films according to a second embodiment. [Figure 6] 6A to 6C are diagrams showing an outline of products etc. in the process of the method of recycling used PET film shown in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0014] First Embodiment Hereinafter, a method for recycling used PET films according to a first embodiment of the present invention will be described with reference to the drawings.

[0015] First, we will explain about used PET film with ceramics attached to its surface.

[0016] PET film is used in the intermediate process of manufacturing multilayer electronic components such as multilayer ceramic capacitors. When PET film is used in the intermediate process of manufacturing multilayer electronic components, ceramics adhere to the surface of the PET film. When the multilayer electronic components are removed from the PET film in the intermediate process, the used PET film with the ceramics remaining on its surface becomes eligible for recycling.

[0017] The PET film is, for example, long and contains at least PET (polyethylene terephthalate) and silicone resin. The PET film has, for example, a PET content of 98% and a silicone resin content of 2% (for example, a PET content of 98% and a silicone resin content of 2%), and its chemical properties (structural formula) is (-CO-[C6H4]-CO-O-(CH2)2-O-)n. The used PET film is a PET film that has been used in the manufacture of laminated electronic components, and the ceramics described above remain and adhere to the surface of the used PET film.

[0018] Next, the adhesion of ceramics to the surface of a PET film will be described with reference to Fig. 1. Fig. 1 is a diagram showing an outline of the manufacturing process of a multilayer ceramic capacitor, to explain the adhesion of ceramics to the surface of a PET film used in a method for recycling used PET film.

[0019] The PET film 1 is, for example, long and includes at least PET and a silicone resin, and has a base film and a release layer formed on one side of the base film. The base film contains PET, and the release layer contains a silicone resin. By including the silicone resin in the release layer, the release layer can be made to have excellent release properties, and the amount of ceramic residue remaining on the surface of the release layer after removing the ceramic green sheet described below can be reduced.

[0020] As shown in Fig. 1(A), a slurry containing a dielectric ceramic powder, a binder, an organic solvent, etc. is applied in sheet form to the surface of a release layer constituting a PET film 1 by a doctor blade method or the like, and the organic solvent component is dried and removed to form a ceramic green sheet 2. The binder material is, for example, polyvinyl butyral (PVB) resin, etc. The organic solvent material is, for example, ethanol, toluene, etc.

[0021] 1(B), electrode patterns 3A to 3F are formed by screen-printing an electrode paste containing, for example, nickel on the surface of the ceramic green sheet 2. In FIG. 1, for the sake of simplicity, each of the electrode patterns 3A to 3F is represented by a square (□).

[0022] The ceramic green sheet 2 on which the electrode patterns 3A to 3F are formed is cut into rectangles, and the cut rectangular portions are peeled off from the PET film 1 to produce parts 4A to 4F of the multilayer ceramic capacitor (for one layer) as shown in Figure 1(C).

[0023] Furthermore, when the cut rectangular portion is peeled off from the PET film 1, a remnant 5 of the ceramic green sheet 2 remains on the used PET film 100, as shown in Figure 1(C). In this way, a used PET film 100 with ceramics attached to its surface is produced.

[0024] A predetermined number of parts for one layer of the multilayer ceramic capacitor are laminated. For example, as shown in Fig. 1(D), three parts 4A to 4C for one layer of the multilayer ceramic capacitor are laminated as the predetermined number, and an electrode pattern is formed on the outer surface of the laminated body to manufacture the multilayer ceramic capacitor 6.

[0025] The above-mentioned used PET film with ceramics attached to its surface is one example, and in the first embodiment, any used PET film with ceramics attached to its surface is eligible for recycling, regardless of how the ceramics became attached to the surface of the used PET film.

[0026] Next, the steps of the method for recycling used PET film having ceramics attached to its surface will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a diagram showing the steps of the method for recycling used PET film according to the first embodiment. Fig. 3 is a diagram showing an outline of the products and the like in the steps of the method for recycling used PET film shown in Fig. 2.

[0027] First, a used PET film having ceramics attached to its surface is prepared (preparation of used PET film: step S1). The used PET film contains at least PET and silicone resin. The used PET film has, for example, a PET content of 98% and a silicone resin content of 2% (for example, a PET content of 98% and a silicone resin content of 2%) and a chemical characteristic (structural formula) of (-CO-[CH]-CO-O-(CH)-O-). The used PET film 100 prepared in the preparation of used PET film in step S1 has ceramics 102 attached to a surface 101 of the used PET film 100, as shown in FIG. 3(A). Note that FIG. 3(A) shows the used PET film 100 rolled up.

[0028] The ceramics adhering to the surface of the used PET film are mechanically removed from the used PET film (ceramics removal step: step S2). For example, in the ceramics removal step of step S2, as shown in Fig. 4, the used PET film 100 is unwound by rollers 150, 155, and the used PET film is rewound by rollers 150, 155 while a blade 200 is in contact with the surface 101 of the used PET film 100 to which the ceramics 102 are adhered. During the rewinding of the used PET film 100, the blade 200 contacts the ceramics 102 adhering to the surface 101 of the used PET film 100, thereby peeling and removing the ceramics 102 from the surface 101 of the used PET film 100. Note that a known method can be used for mechanically removing the ceramics in the ceramics removal step (step S2). By the ceramic removal process of step S2, the used PET film 100 having the ceramics 102 attached to the surface 101, the appearance of which is shown in Figure 3(A), becomes the used PET film 100 having the ceramics 102 attached to the surface 101 removed, the appearance of which is shown in Figure 3(B).

[0029] In the ceramic removal process (step S2), the silicone resin contained in the used PET film is left behind, and the ceramics attached to the surface are mechanically removed.In the ceramic removal process (step S2), the silicone resin is left behind when the ceramics attached to the surface are mechanically removed.

[0030] The surface 101 of the used PET film 100 from which the ceramics have been mechanically removed in the ceramics removal step (step S2) is washed (washing step: step S3). This washing is performed using, for example, an organic solvent.

[0031] In the first embodiment, the used PET film 100 after the ceramics 102 adhering to the surface 101 have been removed in the ceramic removal step (step S2) is processed into flakes (flake processing step: step S4). In the flake processing step (step S4), a known method can be used, for example, to crush the used PET film 100 using a known crusher (having a known structure and performing a known operation) to a size that can be fed into a known extruder (having a known structure and performing a known operation). In the flake processing step of step S4, flakes 110 shown in FIG. 3(C) are produced.

[0032] The flakes produced in the flake processing step (step S4) are processed into first pellets (first pellet processing step: step S5). In the first pellet processing step (step S5), a known method can be used, for example, by feeding the flakes produced in the flake processing step (step S4) into a known extruder, thermally melting them in the extruder, and producing first pellets of an easily processable size. In the first pellet processing step of step S5, first pellets 115 shown in FIG. 3(D) are produced.

[0033] An additive is added to the first pellets produced in the first pellet processing step (step S5) (addition step: step S6). In the addition step, the additive is added to the first pellets to adjust the IV (intrinsic viscosity) value of the second pellets produced in the second pellet processing step (step S7) described below to a value within a predetermined range. The IV value represents the inherent viscosity of a material such as PET resin, and the higher the IV value, the more viscous the material. The additive is used to change the IV value of the second pellets produced in the second pellet processing step (step S7) described below.

[0034] For example, when a resin molded product is molded by one of the injection molding processes in the molding process (step S8) described below, an additive is added to the first pellet in the adding process (step S6) to adjust the IV value of the second pellet produced in the second pellet processing process (step S7) described below to a value between 0.4 and 0.8.

[0035] Also, for example, when a resin molded product is molded using two processes, injection molding and blow molding after the injection molding, in the molding process (step S8) described below, an additive is added to the first pellets in the adding process (step S6) to adjust the IV value of the second pellets produced in the second pellet processing process (step S7) described below to a value between 0.6 and 0.8.

[0036] The IV value of the second pellet (an IV value of 0.4 or more and 0.8 or less) when a resin molded product is molded by one injection molding method, and the IV value of the second pellet (an IV value of 0.6 or more and 0.8 or less) when a resin molded product is molded by both injection molding and blow molding after the injection molding, as shown above, are particularly suitable values ​​when using, for example, a PET film (used PET film) with a PET content of 98% and a silicone resin content of 2% (for example, a PET content of 98% and a silicone resin content of 2%) and a chemical property (structural formula) of (-CO-[C6H4]-CO-O-(CH2)2-O-)n.

[0037] In the adding process of step S6, for example, an operator adds the additive 120 to the first pellets 115 as shown in FIG. 3(E), and mixes the first pellets 115 and the additive 120 so that they are evenly dispersed.

[0038] The first pellets to which the additives have been added in the adding step (step S6) are processed into second pellets (second pellet processing step: step S7). In the second pellet processing step (step S7), a known method can be used, such as the method exemplified in the first pellet processing step (step S5) above. In the second pellet processing step of step S7, second pellets 125 shown in FIG. 3(F) are produced.

[0039] The second pellets produced in the second pellet processing step (step S7) are used to mold a resin molded product (molding step: step S8). Methods for molding resin molded products include, for example, known injection molding and known blow molding. Injection molding, sometimes called injection molding, is a molding method in which, for example, heated and molten resin is injected and filled at high temperature and pressure into a set of concave and convex molds, and then cooled and solidified. Blow molding, sometimes called hollow molding, is a molding method in which, for example, heated and molten resin is extruded into a pipe shape (called a parison), the parison is sandwiched between a pair of concave and concave molds, compressed air is blown into the molten parison to inflate it and make it adhere to the inside of the mold, and then cooled and solidified. Resin molded products can also be molded as follows. Heated and molten resin is injected and filled into a mold at high temperature and pressure, and then cooled and solidified to create a preform (injection molding). The heated and molten preform is then sandwiched between molds, and compressed air or the like is blown into the molten preform to inflate it and make it stick to the inside of the mold. The preform is then cooled and solidified (blow molding) to form a resin molded product. In other words, resin molded products are formed using two processes: injection molding and blow molding after injection molding.

[0040] For example, when a resin molded product is molded by one of injection molding in the molding process (step S8), the second pellets having an IV value of 0.4 or more and 0.8 or less are used. The resin molded product molded by one of injection molding is, for example, an exterior cover of an image forming device.

[0041] Furthermore, when a resin molded product is molded by both injection molding and blow molding after the injection molding, the second pellets having an IV value of 0.6 or more and 0.8 or less are used. An example of a resin molded product molded by both injection molding and blow molding after the injection molding is a toner container bottle 130 for an image forming apparatus, the external appearance of which is shown in Figure 3(G).

[0042] As described above, in the ceramic removal step (step S2), the silicone resin contained in the used PET film is left behind, and the ceramics attached to the surface are mechanically removed. By leaving the silicone resin in this way, the resin molded product contains silicone resin. Therefore, the resin molded product molded in the molding step (step S8) is, for example, a sliding part, and the sliding part may be a sliding part of an image forming device or a sliding part other than an image forming device. An example of a sliding part of an image forming device is a toner container bottle 130 of an image forming device that requires sliding properties, which includes gears that require sliding properties.

[0043] The resin molded product molded in the molding process (step S8) (for example, a resin molded product molded by a single injection molding method, a resin molded product molded by a single blow molding method, a resin molded product molded by a combination of injection molding and blow molding after injection molding, etc.) may be, for example, a sliding part of the image forming device described above, a sliding part of a product other than the image forming device described above, a part other than the sliding part of an image forming device, a part other than the sliding part of a product other than an image forming device, or a product (a product requiring sliding properties, a product not requiring sliding properties).

[0044] According to the first embodiment described above, by adding an additive to the first pellets and processing the first pellets with the additive added into second pellets to be used in molding a resin molded product in the molding process of step S8, it becomes possible to produce second pellets having an IV value suitable for the molding process of step S8 (for example, a molding process that performs one type of injection molding, or a molding process that performs two types of injection molding and blow molding after the injection molding), and the uses of recycled used PET film can be expanded to include resin molded products, rather than just as new PET film.

[0045] Furthermore, by processing the first pellets containing the additive to produce second pellets with an IV value of 0.4 or more and 0.8 or less, it is possible to provide second pellets suitable for molding a resin molded product using one of the injection molding methods, and to smoothly mold the resin molded product using one of the injection molding methods. In particular, the IV value of the second pellets of 0.4 or more and 0.8 or less is a value suitable for use with a PET film (used PET film) having a PET content of 98% and a silicone resin content of 2% (for example, a PET content of 98% and a silicone resin content of 2%) and a chemical property (structural formula) of (-CO-[CH]-CO-O-(CH)-O-).

[0046] Furthermore, by adjusting the IV value of the second pellets obtained by processing the second pellets containing the additive to a value of 0.6 to 0.8, it is possible to provide second pellets suitable for molding a resin molded product that involves both injection molding and post-injection molding, thereby enabling smooth molding of the resin molded product that involves both injection molding and post-injection molding. In particular, the IV value of the second pellets of 0.6 to 0.8 is a value suitable for use with, for example, a PET film (used PET film) that contains 98% PET and 2% silicone resin (e.g., 98% PET and 2% silicone resin) and has the chemical property (structural formula) (-CO-[CH]-CO-O-(CH)-O-).

[0047] Second Embodiment A second embodiment of the method for recycling used PET film according to the present invention will be described below with reference to the drawings. The first embodiment of the method for recycling used PET film involves adding additives to first pellets produced by processing flakes, whereas the second embodiment of the method for recycling used PET film involves adding additives to flakes.

[0048] In the second embodiment, similarly to the first embodiment, a used PET film having ceramics attached to its surface is the target for recycling. The PET film is, for example, long and contains at least PET and silicone resin. The PET film has, for example, a PET content of 98% and a silicone resin content of 2% (for example, a PET content of 98% and a silicone resin content of 2%), and has the chemical characteristics (structural formula) of (-CO-[C6H4]-CO-O-(CH2)2-O-)n. The used PET film has been used in the manufacture of laminated electronic components, and the ceramics remain and adhere to the surface of the used PET film.

[0049] Next, steps of a method for recycling used PET film having ceramics attached to its surface will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a diagram showing steps of a method for recycling used PET film according to a second embodiment. Fig. 6 is a diagram showing an outline of products etc. in the steps of the method for recycling used PET film shown in Fig. 5.

[0050] First, a used PET film having ceramics attached to its surface is prepared (preparation of used PET film: step S11). The used PET film contains at least PET and silicone resin. The used PET film has, for example, a PET content of 98% and a silicone resin content of 2% (for example, a PET content of 98% and a silicone resin content of 2%) and has the chemical properties (structural formula) of (-CO-[CH]-CO-O-(CH)-O-). The used PET film 100 prepared in the preparation of used PET film in step S11 has ceramics 102 attached to a surface 101 of the used PET film 100, as shown in FIG. 6(A).

[0051] The ceramics adhering to the surface of the used PET film are mechanically removed from the used PET film (ceramics removal step: step S12). In the ceramics removal step (step S12), a known method can be used, such as the method exemplified in the ceramics removal step (step S2) of the first embodiment. By the ceramics removal step of step S12, the used PET film 100 having the ceramics 102 adhering to the surface 101, the appearance of which is shown in FIG. 6(A), becomes the used PET film 100 having the ceramics 102 adhering to the surface 101 removed, the appearance of which is shown in FIG. 6(B).

[0052] In the ceramic removal process (step S12), the silicone resin contained in the used PET film is left behind, and the ceramics attached to the surface are mechanically removed.In the ceramic removal process (step S12), the silicone resin is left behind when the ceramics attached to the surface are mechanically removed.

[0053] The surface 101 of the used PET film 100 from which the ceramics have been mechanically removed in the ceramics removal step (step S12) is cleaned (cleaning step: step S13) by, for example, a method similar to the cleaning step (step S3) of the first embodiment.

[0054] The used PET film 100 after the ceramics 102 adhering to the surface 101 have been removed in the ceramic removal step (step S12), or in the second embodiment, the used PET film 100 whose surface has been cleaned in the cleaning step (step S13), is processed into flakes (flake processing step: step S14). In the flake processing step (step S14), a known method can be used, such as the method exemplified in the frame processing step (step S4) of the first embodiment. In the flake processing step of step S14, flakes 110 shown in FIG. 6(C) are produced.

[0055] An additive is added to the flakes produced in the flake processing step (step S14) (addition step: step S15). For example, the additive may be the same as the additive added to the first pellets in the addition step (step S6) of the first embodiment. In the addition step, the additive is added to the flakes to adjust the IV value of the pellets produced in the pellet processing step (step S16) described below to a value within a predetermined range.

[0056] For example, when a resin molded product is molded by one of the injection molding processes in the molding process (step S17) described below, an additive is added to the flakes in the adding process (step S15) to adjust the IV value of the pellets produced in the pellet processing process (step S16) described below to a value between 0.4 and 0.8.

[0057] Also, for example, when a resin molded product is molded using two processes, injection molding and blow molding after the injection molding, in the molding process (step S17) described below, an additive is added to the flakes in the adding process (step S15) to adjust the IV value of the pellets produced in the pellet processing process (step S16) described below to a value of 0.6 or more and 0.8 or less.

[0058] The IV value of the pellets when a resin molded product is molded by one of the injection molding methods (IV value of 0.4 or more and 0.8 or less) and the IV value of the pellets when a resin molded product is molded by both injection molding and blow molding after the injection molding (IV value of 0.6 or more and 0.8 or less) shown above are particularly suitable when using, for example, a PET film (used PET film) with a PET content of 98% and a silicone resin content of 2% (for example, a PET content of 98% and a silicone resin content of 2%) and a chemical property (structural formula) of (-CO-[C6H4]-CO-O-(CH2)2-O-)n.

[0059] In the adding step S15, for example, an operator adds the additive 120 to the flakes 110 as shown in FIG. 6(D), and mixes the flakes 110 and the additive 120 so that they are evenly dispersed.

[0060] The flakes to which the additives have been added in the adding step (step S15) are processed into pellets (pellet processing step: step S16). In the pellet processing step (step S16), a known method can be used, such as the method exemplified in the first pellet processing step (step S5) of the first embodiment. In the pellet processing step of step S16, pellets 127 shown in FIG. 6(E) are produced.

[0061] The pellets produced in the pellet processing step (step S16) are used to mold a resin molded product (molding step: step S17). Methods for molding resin molded products include known injection molding and known blow molding. In addition, resin molded products can be molded by two methods: injection molding and blow molding after injection molding.

[0062] For example, when a resin molded product is molded by one of injection molding in the molding process (step S17), pellets having an IV value of 0.4 or more and 0.8 or less are used. The resin molded product molded by one of injection molding is, for example, an exterior cover of an image forming device.

[0063] Furthermore, when a resin molded product is formed by both injection molding and blow molding after the injection molding, pellets having an IV value of 0.6 to 0.8 are used. An example of a resin molded product formed by both injection molding and blow molding after the injection molding is a toner container bottle 130 for an image forming device, the external appearance of which is shown in Figure 6(F).

[0064] As described above, in the ceramic removal step (step S12), the silicone resin contained in the used PET film is left behind, and the ceramics adhering to the surface are mechanically removed. By leaving the silicone resin in this way, the resin molded product contains silicone resin. Therefore, the resin molded product molded in the molding step (step S17) is, for example, a sliding part, and the sliding part may be a sliding part of an image forming device or a sliding part other than an image forming device. An example of a sliding part of an image forming device is a toner container bottle 130 of an image forming device that is equipped with gears and other components that require sliding properties.

[0065] The resin molded product molded in the molding process (step S17) (for example, a resin molded product molded by a single injection molding method, a resin molded product molded by a single blow molding method, a resin molded product molded by a combination of injection molding and blow molding after injection molding, etc.) may be, for example, a sliding part of the image forming device described above, a sliding part of a product other than the image forming device described above, a part other than the sliding part of an image forming device, a part other than the sliding part of a product other than an image forming device, or a product (a product requiring sliding properties, a product not requiring sliding properties).

[0066] According to the second embodiment described above, by adding additives to flakes and processing the flakes with the added additives into pellets to be used in molding resin molded products in the molding process of step S17, it becomes possible to produce pellets having an IV value suitable for the molding process of step S17 (for example, a molding process that performs one type of injection molding, or a molding process that performs two types of injection molding and blow molding after the injection molding), and the uses of recycled used PET film can be expanded to include resin molded products rather than just as new PET film.

[0067] Furthermore, by adjusting the IV value of the pellets obtained by processing the additive-added flakes to a value of 0.4 or more and 0.8 or less, pellets suitable for molding a resin molded product using one of the injection molding methods can be provided, and molding of a resin molded product using one of the injection molding methods can be smoothly performed. In particular, the IV value of the pellets of 0.4 or more and 0.8 or less is a value suitable for use with, for example, a PET film (used PET film) having a PET content of 98% and a silicone resin content of 2% (for example, a PET content of 98% and a silicone resin content of 2%) and a chemical property (structural formula) of (-CO-[CH]-CO-O-(CH)-O-).

[0068] Furthermore, by adjusting the IV value of the pellets obtained by processing the additive-added flakes to a value of 0.6 or more and 0.8 or less, pellets suitable for molding a resin molded product that involves both injection molding and post-injection molding can be provided, and molding of a resin molded product that involves both injection molding and post-injection molding can be smoothly performed. In particular, the IV value of the pellets of 0.6 or more and 0.8 or less is a value suitable for use with, for example, a PET film (used PET film) that contains 98% PET and 2% silicone resin (for example, 98% PET and 2% silicone resin) and has the chemical property (structural formula) (-CO-[CH]-CO-O-(CH)-O-).

[0069] In addition, in the second embodiment, the pellet processing step is one of the pellet processing steps in step S16, so the number of steps from the ceramic removal step (step S12) to the molding step (step S17) can be reduced, making it possible to reduce the manufacturing costs of resin molded products.

[0070] The present invention is not limited to the configurations of the above-described embodiments or modified examples, and various modifications are possible. Furthermore, the configuration and steps shown in the first embodiment using Figures 1 to 4 and the configuration and steps shown in the second embodiment using Figures 5 to 6 are merely one embodiment of the present invention, and are not intended to limit the present invention to these configurations and steps. [Explanation of symbols]

[0071] S1 Preparing used PET film S2 Ceramics removal process S3 Cleaning process S4 Flake processing process S5 First pellet processing process S6 addition process S7 Second pellet processing process S8 Molding process S11 Preparation of used PET film S12 Ceramics removal process S13 Cleaning process S14 Flake processing process S15 Addition process S16 Pellet processing process S17 Molding process

Claims

1. A method for recycling used PET film having ceramics attached to its surface, comprising the steps of: a removing step of mechanically removing the ceramics adhering to the surface of the used PET film from the used PET film; a flake processing step of processing the used PET film into flakes after the ceramics attached to the surface have been removed in the removing step; a first pellet processing step of processing the flakes produced in the flake processing step into first pellets; an adding step of adding an additive to the first pellets produced in the first pellet processing step; a second pellet processing step of processing the first pellets to which the additive has been added in the adding step into second pellets; a molding step of molding a resin molded product using the second pellets processed in the second pellet processing step; Equipped with In the adding step, the additive is added to the first pellets to adjust the IV value of the second pellets to a value within a predetermined range. How to recycle used PET film.

2. 2. The method for recycling used PET film according to claim 1, wherein, when the resin molded product is molded by one of injection molding in the molding step, the additive is added to the first pellets in the adding step to adjust the IV value of the second pellets to a value of 0.4 or more and 0.8 or less.

3. 2. The method for recycling used PET film according to claim 1, wherein, when the molding step involves molding the resin molded product by two steps, namely, injection molding and blow molding after the injection molding, the adding step involves adding the additive to the first pellets to adjust the IV value of the second pellets to a value of 0.6 or more and 0.8 or less.

4. The used PET film contains at least PET and a silicone resin, 2. The method for recycling used PET film according to claim 1, wherein in the ceramic removing step, the ceramic adhering to the surface is mechanically removed while leaving the silicone resin.

5. The method further includes a cleaning step, which is performed between the removing step and the flake processing step, of cleaning the surface of the used PET film from which the ceramics have been mechanically removed in the removing step; The used PET film used in the flake processing step is the used PET film whose surface has been cleaned. The method for recycling used PET film according to any one of claims 1 to 4.

6. A method for recycling used PET film having ceramics attached to its surface, comprising the steps of: a removing step of mechanically removing the ceramics adhering to the surface of the used PET film from the used PET film; a flake processing step of processing the used PET film into flakes after the ceramics attached to the surface have been removed in the removing step; an adding step of adding an additive to the flakes produced in the flake processing step; a pellet processing step of processing the flakes to which the additives have been added in the adding step into pellets; a molding step of molding a resin molded product using the pellets processed in the pellet processing step; Equipped with In the adding step, the additive is added to the flakes to adjust the IV value of the pellets to a value within a predetermined range. How to recycle used PET film.

7. 7. The method for recycling used PET film according to claim 6, wherein, when the molding step is performed to mold the resin molded product by one of injection molding, the adding step adds the additive to the flakes to adjust the IV value of the pellets to a value of 0.4 or more and 0.8 or less.

8. 7. The method for recycling used PET film according to claim 6, wherein, when the molding step involves molding the resin molded product by two steps, injection molding and blow molding after the injection molding, the adding step involves adding the additive to the flakes to adjust the IV value of the pellets to a value of 0.6 or more and 0.8 or less.

9. The used PET film contains at least PET and a silicone resin, 7. The method for recycling used PET film according to claim 6, wherein in the ceramic removing step, the ceramic adhering to the surface is mechanically removed while leaving the silicone resin.

10. The method further includes a cleaning step, which is performed between the removing step and the flake processing step, of cleaning the surface of the used PET film from which the ceramics have been mechanically removed in the removing step; The used PET film used in the flake processing step is the used PET film whose surface has been cleaned. The method for recycling used PET film according to any one of claims 6 to 9.

11. A pellet manufactured using a used PET film having ceramics attached to its surface, The ceramics adhering to the surface of the used PET film are mechanically removed from the used PET film; The used PET film after the ceramics attached to the surface are removed is processed into flakes; the flakes are processed into first pellets; adding an additive to the first pellet to adjust the IV value of the pellet to a value within a predetermined range; Pellets produced by processing the first pellets to which the additives have been added.

12. The pellet according to claim 11, wherein when the pellet is used to form a resin molded product by injection molding, the additive is added to the first pellet to set the IV value of the pellet to a value of 0.4 or more and 0.8 or less.

13. The pellet according to claim 11, wherein, when a resin molded product is molded using the pellets by two processes, injection molding and blow molding after the injection molding, the additive is added to the first pellets to set the IV value of the pellets to a value of 0.6 or more and 0.8 or less.

14. The pellet according to claim 11, wherein the used PET film contains at least PET and a silicone resin, and when the ceramics attached to the surface are mechanically removed, the silicone resin remains.

15. A pellet manufactured using a used PET film having ceramics attached to its surface, The ceramics adhering to the surface of the used PET film are mechanically removed from the used PET film; The used PET film after the ceramics attached to the surface are removed is processed into flakes; adding an additive to the flakes to bring the IV value of the pellets to a predetermined range; Pellets are produced by processing the flakes to which the additives have been added.

16. 16. The pellet according to claim 15, wherein when the pellet is used to form a resin molded product by injection molding, the additive is added to the flakes to set the IV value of the pellet to a value of 0.4 or more and 0.8 or less.

17. 16. The pellet according to claim 15, wherein, when the pellet is used to form a resin molded product by two processes, injection molding and blow molding after the injection molding, the additive is added to the flakes to set the IV value of the pellet to a value of 0.6 or more and 0.8 or less.

18. The pellet according to claim 15, wherein the used PET film contains at least PET and a silicone resin, and when the ceramics attached to the surface are mechanically removed, the silicone resin remains.

19. A resin molded product molded using the pellet according to any one of claims 11 to 18.

20. 20. The resin molded product according to claim 19, wherein the resin molded product is a sliding part molded using the pellet according to claim 14 or 18.

21. The resin molded product according to claim 20, wherein the sliding part is a sliding part of an image forming apparatus.

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