Tray or carrier tape for conveying electronic component, method for manufacturing same, and method for recycling same

Abstract

Provided are: a conveyance tray or carrier tape for an electronic component, the conveyance tray or carrier tape being capable of recycling and reusing a substrate; and a method for recycling same.　This conveyance tray or carrier tape for an electronic component comprises: a substrate layer which is a plastic sheet; a conductive ink layer disposed on at least one surface of the substrate layer; and an intermediate layer which is disposed between the substrate layer and the conductive ink layer and allows the conductive ink layer to be removed in an alkaline solution, wherein the surface resistance value on the conductive ink layer is 1×103 to 1×1013 Ω / □.

Description

Tray or carrier tape for transporting electronic components, and manufacturing method and recycling method thereof

[0001] The present invention relates to a carrier tray or carrier tape for electronic components, and a method for manufacturing and recycling the same.

[0002] BACKGROUND ART In response to the demand for smaller, lighter, and more functional electronic devices incorporating electronic components, electronic components are transported on trays or carrier tapes and incorporated into electronic device products during the manufacture of electronic devices.

[0003] An electronic component transport tray is a tray made of synthetic resin that has multiple storage compartments for storing electronic components, such as semiconductor chips, liquid crystal modules, and hard disk components, formed to fit the shape of the components using vacuum molding or other methods, and carrier tapes are also used to transport and mount the electronic components. Electronic component transport trays are stacked one on top of another with electronic components inserted in the storage compartments, and are wound up on carrier tapes together with the electronic components for transport and storage.

[0004] With such transport trays or carrier tapes for electronic components, static electricity can be generated during transport, storage, or other handling due to friction between the transport tray or carrier tape and the electronic components, or between the transport trays or carrier tapes themselves.This static electricity can cause problems, so it is necessary to impart conductivity to the transport trays or carrier tapes for electronic components to suppress the generation of static electricity.

[0005] To suppress the generation of static electricity, methods have been considered in the past, such as coating the surface of a synthetic resin sheet that has rigidity, formability, shape retention, etc., and that serves as the base material for trays or carrier tapes for transporting electronic components, with carbon nanotubes (Patent Document 1) or a conductive ink containing a conductive polymer.

[0006] Currently, conductive ink-coated transport trays or carrier tapes for electronic components are discarded after use because the conductive ink cannot be easily removed. However, plastic recycling is required as an important initiative to realize a carbon-free society and curb global warming.

[0007] Conventionally, as a technique for removing a printed layer from a printed plastic sheet, a method has been proposed in which an intermediate layer made of a release ink containing a resin composition that can swell or dissolve in an alkaline solution is provided between the plastic sheet and the printed layer, and the printed plastic sheet is treated in an alkaline solution to release and remove the printed layer and release layer (Patent Documents 2 to 6).

[0008] Patent No. 6656450 Patent No. 3934292 Patent No. 6388131 Patent No. 6631964 Patent No. 6928766 Patent No. 7100750

[0009] However, transport trays or carrier tapes for electronic components need to be made conductive to suppress the generation of static electricity, and there is a problem that if an intermediate layer that allows the conductive ink layer to be removed in an alkaline solution is provided, the conductive ink layer does not have the desired conductivity.

[0010] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a transport tray or carrier tape for electronic components whose base material can be recycled and reused, as well as a manufacturing method and a recycling method thereof.

[0011] Although ink that can be removed with an alkaline solution is an existing technology, combining it with a conductive ink layer has not been considered. The reason why the conductive ink layer does not have the desired conductivity when an intermediate layer is provided is thought to be due to the unevenness of the intermediate layer and stretching due to vacuum molding, etc. Therefore, the present inventors conducted extensive research and found that a conductive tray that achieves both conductivity and releasability can be obtained by adjusting the thickness of the conductive ink layer, thereby completing the present invention. That is, the transport tray or carrier tape for electronic components of the present invention comprises a base layer that is a plastic sheet; a conductive ink layer provided on at least one side of the base layer; and an intermediate layer provided between the base layer and the conductive ink layer that removes the conductive ink layer in an alkaline solution, and the surface resistance of the conductive ink layer side is 1×10 3 ~×1×10 13The electronic component carrier tray or carrier tape is preferably a molded product obtained by stretching a laminate sheet of the substrate layer, conductive ink layer, and intermediate layer. The electronic component carrier tray or carrier tape preferably has a thickness such that, when the laminate sheet of the substrate layer, conductive ink layer, and intermediate layer is stretched to a stretch ratio of 2, calculated from the ratio of the thicknesses before and after stretching, the resistance increase rate of the stretched portion is 80 times or less. The electronic component carrier tray or carrier tape preferably has an intermediate layer containing a resin composition that is swellable or soluble in an alkaline solution. The method for producing a carrier tray or carrier tape for electronic components of the present invention is characterized by comprising a step of stretching and molding the laminate sheet of the substrate layer, conductive ink layer, and intermediate layer. The method for recycling a carrier tray or carrier tape for electronic components of the present invention is characterized by comprising the steps of: immersing the carrier tray or carrier tape for electronic components in an alkaline solution to swell or dissolve the intermediate layer provided between the base layer and the conductive ink layer, and removing at least the conductive ink layer from the carrier tray or carrier tape for electronic components; and recycling the base layer from which the conductive ink layer has been removed as a molding material.

[0012] According to the present invention, by providing an intermediate layer between the conductive ink layer and the substrate layer, which allows the conductive ink layer to be removed in an alkaline solution, the tray or carrier tape for transporting electronic components can be immersed in an alkaline solution to remove the conductive ink layer and the intermediate layer, and the substrate layer can be returned to an unprinted state, thereby making it possible to recycle and reuse the substrate.

[0013] Fig. 1 is a longitudinal cross-sectional view schematically showing the layer structure of a carrier tray or carrier tape for electronic components of the present invention. Fig. 2 is a graph showing the relationship between coating thickness and resistance value for test pieces in which the coating thickness of conductive ink was changed without providing an intermediate layer (release ink). Fig. 3 is a graph of a conformability test showing the relationship between the stretch ratio in vacuum molding and resistance value for test pieces in which the coating thickness of conductive ink was changed. Fig. 4 is a graph showing the results of a conformability test in an example. Fig. 5 is a graph showing the results of a conformability test in a comparative example.

[0014] Hereinafter, an embodiment of the present invention will be described.

[0015] The carrier tray or carrier tape for electronic components of the present invention comprises a base layer that is a plastic sheet, a conductive ink layer provided on at least one side of the base layer, and an intermediate layer provided between the base layer and the conductive ink layer that allows the conductive ink layer to be removed in an alkaline solution. Figure 1 is a longitudinal cross-sectional view schematically showing the layer structure of the carrier tray or carrier tape for electronic components of the present invention. In this example, an intermediate layer 3 is provided between the base layer 1 and a conductive ink layer 2 provided on one side thereof, and allows the conductive ink layer 2 to be removed in an alkaline solution. Note that the intermediate layer 3 and the conductive ink layer 2 may be provided on both sides of the base layer 1.

[0016] The substrate layer is a long plastic sheet that imparts rigidity, moldability, shape retention, and the like to the carrier tray or carrier tape for electronic components. A moldable resin material can be used for the substrate layer. Examples of resin materials include synthetic resins, and thermoplastic resins are preferred. Specific examples include polyester resins such as amorphous polyethylene terephthalate resin (A-PET), polyolefin resins such as polypropylene resin, polystyrene resin, polyamide resin, polyvinyl chloride resin, polycarbonate resin, and acrylonitrile-butadiene-styrene copolymer resin (ABS resin). Other components, such as known additives typically incorporated into resin materials, can be incorporated into the substrate layer within a range that does not impair the effects of the present invention.

[0017] In the case of a carrier tray for electronic components, the thickness of the base layer is preferably 0.2 to 2.0 mm, more preferably 0.4 to 1.4 mm, from the viewpoints of strength and formability. In the case of a carrier tape for electronic components, the thickness of the base layer is preferably 0.1 to 1.0 mm, more preferably 0.2 to 0.4 mm, from the viewpoints of strength and formability.

[0018] The conductive ink layer is formed by applying and drying a conductive ink. The conductive ink is a dispersion in which a conductive material is dispersed in a liquid. The conductive ink contains the conductive material and a solvent such as water or an organic solvent, and may also contain other components such as a binder resin. For example, known conductive inks or commercially available conductive inks can be used. Examples of conductive materials include conductive carbon materials, conductive polymers, metal particles, and conductive oxide particles. Examples of conductive carbon materials include conductive carbon black, carbon nanotubes, graphene, graphite, and conductive carbon fibers. Examples of conductive polymers include polythiophenes, polypyrroles, polyanilines, polyazulenes, polyindoles, polycarbazoles, polyacetylenes, polyfurans, polyparaphenylene vinylenes, polyazulenes, polyparaphenylenes, polyparaphenylene sulfides, polyisothianaphthenes, and polythiazyls. Examples of polythiophenes include PEDOT / PSS (poly(styrene sulfonate)) containing PEDOT (poly(3,4-ethylenedioxythiophene)). Examples of metals or alloys include gold, platinum, silver, copper, nickel, rhodium, palladium, magnesium, chromium, titanium, iron, and alloys thereof. Examples of conductive oxide particles include indium tin oxide (ITO), indium zinc oxide (IZO), and the like.

[0019] The thickness of the conductive ink layer is preferably such that, when a laminate sheet of the substrate layer, conductive ink layer, and intermediate layer is stretched to a stretch ratio of 2, calculated from the ratio of the thicknesses before and after stretching, the resistance increase rate of the stretched portion is within 80 times, more preferably within 50 times, and even more preferably within 20 times. Here, the laminate sheet is a dried laminate sheet in which a release ink is printed on the substrate and a conductive ink is overprinted on the release ink, thereby providing an intermediate layer and a conductive ink layer on the substrate. The substrate may be a substrate for a transport tray or carrier tape for electronic components actually manufactured. However, as a standard, the resistance increase rate may be measured using a 0.5 mm thick amorphous polyethylene terephthalate resin (A-PET) or polypropylene resin (PP). The stretching method used to measure the resistance increase rate is not particularly limited, but it can be performed, for example, by processing the substrate by vacuum molding.

[0020] If the thickness of the conductive ink layer is within the above range, the increase in resistance value due to stretching can be suppressed, and the resistance value will not increase significantly from the target value when the conductive ink is applied to the substrate without providing an intermediate layer to form the conductive ink layer.

[0021] The thickness of the conductive ink layer is preferably thicker than usual to reduce the rate of increase in resistance and to reduce the resistance value after stretching. However, if the thickness is too thick, drying takes a long time, resulting in reduced productivity. The required thickness of the conductive ink varies depending on the type, shape, size, and original conductivity of the conductive material. However, depending on the type of conductive material, it is preferably within a range of 1.5 to 3.0 times the standard thickness at which the target resistance value is obtained when applied to a substrate without an intermediate layer. For example, when the conductive material is a carbon nanotube ink, the thickness of the conductive ink layer is preferably within a range of 1.5 to 3.0 times the standard thickness of 0.3 μm. When the conductive material is a conductive polymer ink, the thickness of the conductive ink layer is preferably within a range of 1.5 to 3.0 times the standard thickness of 1.0 μm.

[0022] The intermediate layer uses a release ink, which is a conventional technique for removing and stripping a printed layer from a printed substrate layer. Patent documents 2 to 6 disclose such release inks, and their descriptions are incorporated herein by reference. This release ink allows the primer layer printed with the ink and the printed layer printed thereon to be easily removed from the substrate layer using an alkaline solution. Note that "release" includes both cases in which the intermediate layer peels off from the substrate without dissolving and cases in which it dissolves and peels off. The ink swells or dissolves in the alkaline solution, thereby allowing the conductive ink layer to be removed from the substrate layer. By providing an intermediate layer of release ink on the surface of the substrate layer of a plastic sheet, during recycling, the intermediate layer on which the conductive ink layer is formed is peeled off from the substrate layer by the alkaline solution, and the upper conductive ink layer (ink coating) peels off together with the intermediate layer without breaking into small pieces, facilitating post-processing. Neutralization with an alkaline solution allows the treatment liquid to reach the intermediate layer, which becomes hydrophilic as a result of neutralization, or loses its adhesiveness to the base layer as a result of swelling.The intermediate layer, together with the conductive ink layer, spontaneously falls off from the base layer in a film or lump state, making post-processing such as separation of the detached material easier.

[0023] The intermediate layer contains a resin composition that can swell or dissolve in an alkaline solution. The resin composition of the intermediate layer has, for example, acidic functional groups or hydroxyl groups whose charge characteristics change depending on the pH, and the acid value and hydroxyl value are adjusted taking into consideration the releasability in an alkaline solution and the substrate adhesion, etc., so that the conductive ink layer and the substrate layer adhere to each other while swell or dissolve in the alkaline solution, thereby separating them. The acidic functional group refers to a functional group that can be neutralized with potassium hydroxide when measuring the acid value. Specific examples include a carboxyl group and a sulfonic acid group, and the carboxyl group is preferred.

[0024] Examples of resin skeletons that swell or dissolve in alkaline solutions include polyester resins, polyacrylic resins, acrylic-modified polyester resins, polyurethane resins, acrylic-modified polyurethane resins, polyolefin resins, rosin resins, and styrene-maleic acid copolymer resins. These may be used alone or in combination of two or more. The acidic functional group or hydroxyl group is introduced into these resin skeletons by, for example, homopolymerization or copolymerization using a polymerizable monomer having an acidic functional group or hydroxyl group. Furthermore, the intermediate layer may be formed by mixing a low-molecular-weight compound having an acidic functional group with a resin that is film-forming at room temperature, or may contain a resin having an ester structure that is easily decomposed in alkaline solutions.

[0025] The intermediate layer release ink can be produced by dissolving and / or dispersing a resin composition that is swellable or soluble in an alkaline solution in an aqueous or solvent-based solvent, and may contain other components such as known additives, if necessary.

[0026] The thickness of the intermediate layer is preferably 1.5 to 4.0 μm, more preferably 2.0 to 3.0 μm, from the viewpoint of releasability and followability of the conductive ink.

[0027] In the carrier tray or carrier tape for electronic components of the present invention, an intermediate layer and a conductive ink layer can be provided on the substrate, for example, by printing a release ink on the substrate and then printing a conductive ink on top of the release ink. Printing may be on either one side or both sides. The printing method is not particularly limited, but for example, a gravure printer, reverse gravure printer, comma coater, lip coater, etc. can be used. The release ink and the conductive ink can be printed and then dried to form the intermediate layer and the conductive ink layer.

[0028] The surface resistance value of the surface on which the conductive ink layer is formed is set to 1×10 in view of the conductivity required for the transport tray or carrier tape for electronic components and printability with a short drying time of the ink. 3 ~×1×10 13 Ω / □ is preferred, and 1×10 4 ~×1×10 12 Ω / □ is more preferable, and 1×105 ~×1×10 11 Ω / □ is more preferred.

[0029] The carrier tray or carrier tape for electronic components of the present invention is preferably a molded product that involves stretching of a laminated sheet of a base layer, a conductive ink layer, and an intermediate layer. The molding method that involves stretching is not particularly limited, and known methods such as vacuum molding, press molding, pressure molding, and vacuum pressure molding can be used. Among these, the carrier tray or carrier tape for electronic components of the present invention is preferably processed by vacuum molding.

[0030] A carrier tray for electronic components is made by molding a sheet to form numerous pocket-like storage sections that correspond to the size and shape of the electronic components to be placed on it. For example, electronic components, such as semiconductor elements, are inserted into the storage sections of the carrier tray for electronic components. The trays are stacked in multiple layers and transported to the required location, stored, and then picked up from the trays for use in a subsequent process.

[0031] Carrier tapes for electronic components are made by molding a sheet to form numerous pocket-like storage compartments that fit the size and shape of the electronic components to be mounted. For example, electronic components, such as semiconductor elements, are inserted into the storage compartments, sealed with cover tape, and then wound onto a reel, transported to a required location, stored, and then picked up from the tape for use in a subsequent process.

[0032] (Method for recycling carrier trays or carrier tapes for electronic components) The carrier trays or carrier tapes for electronic components of the present invention can be recycled by a method including the following steps A and B. (Step A) A step of immersing the carrier trays or carrier tapes for electronic components in an alkaline solution to swell or dissolve the intermediate layer provided between the base layer and the conductive ink layer, thereby removing at least the conductive ink layer from the carrier trays or carrier tapes for electronic components. (Step B) A step of recycling the base layer from which the conductive ink layer has been removed as a molding material.

[0033] In step A, the intermediate layer of the anchor coat swells or dissolves in the alkaline solution, causing the intermediate layer and the conductive ink layer to detach from the substrate. This includes both cases where the intermediate layer detaches due to neutralization and swelling, and cases where the intermediate layer detaches due to dissolution.

[0034] Since the purpose is to obtain the substrate after detachment as a recycled substrate, it is preferable to remove as much of the intermediate layer and conductive ink layer as possible from the substrate. Specifically, it is preferable that at least 50% by mass or more of the intermediate layer (100% by mass) is detached in the area and film thickness direction. More preferably, it is 60% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more.

[0035] The alkaline compound used in the alkaline solution is not particularly limited, and examples thereof include sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonia, barium hydroxide, and sodium carbonate. Sodium hydroxide and potassium hydroxide are preferred. The solvent for the alkaline solution is not particularly limited, but a solvent mainly containing water is preferred. In order to maintain sufficient basicity to swell or dissolve the intermediate layer and detach the substrate, the alkaline solution preferably contains 0.5 to 20% by mass of the alkaline compound relative to the entire solution, more preferably 1 to 15% by mass, and even more preferably 3 to 15% by mass.

[0036] The alkaline solution penetrates the edge of the laminate sheet of the substrate layer, intermediate layer, and conductive ink layer, contacts the intermediate layer, and swells or dissolves it, thereby separating the substrate layer from the intermediate layer and conductive ink layer. Therefore, to efficiently proceed with the removal process, it is preferable that the transport tray or carrier tape for electronic components is cut or crushed so that the intermediate layer is exposed on the cross section when immersed in the alkaline solution. In this case, the substrate layer can be removed in a shorter time.

[0037] The temperature of the alkaline solution when the carrier tray or carrier tape for electronic components is immersed is preferably 25 to 120°C, more preferably 30 to 120°C, and even more preferably 30 to 80°C. The immersion time in the alkaline solution is preferably 1 minute to 24 hours, more preferably 1 minute to 12 hours, and even more preferably 1 minute to 6 hours. In order to improve the desorption efficiency, it is preferable to stir or circulate the alkaline solution.

[0038] In step B, the substrate layer from which the intermediate layer and conductive ink layer have been removed is recycled as a molding material. The intermediate layer is peeled off from the substrate layer together with the conductive ink layer, and the substrate is detached and recovered. The alkaline aqueous solution is then removed by washing the substrate with water. A drying step may be further included as necessary. This allows the recycled substrate to be obtained.

[0039] The resulting recycled substrate can be processed into pellets using an extruder or the like and reused as recycled resin. Specifically, this process includes, for example, melting and recycling the substrate layer from which the intermediate layer and conductive ink layer have been removed. Various additives can be added as needed, and the resulting resin composition can be mixed or melt-kneaded using a kneader, extruder, or the like to obtain a resin composition in the form of pellets, powder, granules, beads, or the like. Furthermore, a masterbatch can be mixed with the recycled resin to form a molding material. The masterbatch is not particularly limited as long as it is compatible with the recycled resin, and various thermoplastic resins can be used. The masterbatch may be mixed with known additives, such as colorants, including inorganic pigments and organic pigments. The resulting molding material can be molded by, for example, injection molding, extrusion molding, blow molding, compression molding, or the like to obtain a molded product. This molding material not only has a high recycling rate, but also has moldability, and since the recycled resin is light in color, it is possible to provide molded bodies that are uniformly colored from light to dark colors regardless of the molding method mentioned above, and it can be used to recycle transport trays or carrier tapes for electronic components, as well as other molded products.

[0040] The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to these examples.

[0041] (Base Material) Amorphous polyethylene terephthalate resin (A-PET) or polypropylene resin (PP) having a thickness of 0.5 mm was used as the plastic sheet.

[0042] (Conductive ink) CNT ink 32 g of multi-walled carbon nanotubes (NC7000 manufactured by Nanocyl Corporation) and 100 g of dispersant were added dropwise to 2400 g of a mixed solvent of pure water and isopropanol at a ratio of 5:1, and then dispersed for 130 minutes using an ultrasonic disperser to prepare a CNT dispersion. 1620 g of an aqueous dispersion of thermoplastic saturated polyester resin (Pesresin A-645GH manufactured by Takamatsu Oil & Fat Co., Ltd.) was mixed with this CNT dispersion to obtain a CNT ink.

[0043] Aniline Ink: 9 g of polymethyl methacrylate resin (PMMA, Fujifilm Wako Pure Chemical Industries) was dissolved in 51 g of a 1:1 toluene:methyl ethyl ketone mixed solvent to prepare a PMMA solution. 225 g of ion-exchanged water and 103 g of ammonium persulfate were added dropwise to a mixture of 120 g of ion-exchanged water, 15 g of dodecylbenzenesulfonic acid, 34 g of aniline, and 3 g of sulfuric acid, and the water was then removed to prepare a polyaniline pigment. This polyaniline pigment and PMMA solution were mixed and dispersed using a high-speed stirrer for 30 minutes to obtain an aniline ink.

[0044] (Release Ink) The following release inks were used. Release Ink 1: Oil-based anchor coating agent manufactured by Toyo Ink Co., Ltd. Release Ink 2: Water-based anchor coating agent manufactured by Toyo Ink Co., Ltd. Release Ink 3: PESRESIN A-680 (water dispersion of thermoplastic saturated polyester resin) manufactured by Takamatsu Yushi Co., Ltd.

[0045] (Preparation of Test Piece) The release ink was printed on a substrate using a bar coater, and then the conductive ink was printed on top of the release ink using the bar coater to prepare a test piece.

[0046] Test method: Releasability 3 g of sodium hydroxide was added to 197 g of pure water and stirred with a magnetic stirrer to dissolve, preparing a 1.5% sodium hydroxide solution as an alkaline solution. The test piece was stirred in the alkaline solution under the following conditions, and the ink releasability was confirmed. The evaluation criteria were as follows: the color difference ΔE*ab between the raw paper and the test piece from which the ink had been removed was measured using a spectrophotometer (Nippon Denshoku Industries Co., Ltd.), and a ΔE*(ab) of less than 3 was evaluated as ◯, and a ΔE*(ab) of 3 or more was evaluated as ×. <Releasability test conditions> Test piece: 2.5 cm square Stirring method: Magnetic stirrer Test temperature: 70°C Test time: 10 minutes

[0047] After vacuum molding using a cylindrical mold, the resistance and thickness of each stretched portion were measured. The resistance was measured using a surface resistance measuring device ULTRA MEGOHMMETER SM 8220 (manufactured by DKK-TOA Corporation), and the thickness was measured using a DIGIMATIC MICROMETER (manufactured by Mitutoyo Corporation). The stretching ratio was calculated from the ratio of the thickness before and after stretching. The evaluation criteria were as follows: a substrate with a thickness of 0.5 mm was processed by vacuum molding, and the portion stretched to 0.25 mm was stretched twice; if the resistance increase rate after 2 times stretching was within 50 times, it was evaluated as ◯; if the resistance increase rate was more than 50 times and less than 80 times, it was evaluated as △; and if the resistance increase rate exceeded 80 times, it was evaluated as ×.

[0048] Productivity: Judgment was made based on factors such as printability (e.g., ink drying speed) when printing on a production machine, as well as cost.

[0049] Evaluation of recycled pellets After the alkali release test, each test piece was cut into small pieces, extruded using a single-screw extruder, and quenched with water to produce pellets. The color difference ΔE*ab between the produced pellets and pellets produced from the raw roll was measured using a spectrophotometer (Nippon Denshoku Industries Co., Ltd.) to confirm whether the pellets could be recycled to the state of the raw roll. The evaluation criteria were as follows: ∘ if ΔE*(ab) was less than 3, and × if 3 or more.

[0050] (1) Reference thickness of conductive ink CNT ink was used as the conductive ink, and the resistance value was measured by changing the thickness of the conductive ink applied to the substrate using bar coaters No. 2 to No. 24. The results are shown in Figure 2. The resistance value decreases as the thickness of the conductive ink applied increases. The resistance value of the transport tray or carrier tape using CNT ink was 1 x 10 7 The thickness of the bar coater No. 4, which provides a sufficient resistance value, was used as the reference coating thickness.

[0051] (2) Detachable Ink Coating Thickness The above-mentioned detachable ink coating tests were conducted by changing the coating thickness of detachable inks 1 and 2 by changing the bar coater No. 2 to No. 24 used to coat the detachable ink on the substrate. The results are shown in Table 1. If the coating thickness of the detachable ink is thin, the film stress of the detachable ink layer is weak, resulting in some parts not being cleanly detachable as a film (Table 1 lists the color difference between the areas where the ink has not been detached and the areas where it has been detached). However, if the coating thickness is too thick, the detachable ink will not stretch during sheet molding, resulting in poor tracking and impairing the conductivity of the electronic component carrier tray or carrier tape. Based on these results, the coating thickness of the detachable ink was set within the range of 1.5 to 4.0 μm, and the ink coating thickness in the following tests was set to 2.0 μm.

[0052] (3) Conductive Ink Coating Thickness with an Intermediate Layer (Released Ink) The above-mentioned conformability test was conducted using CNT ink as the conductive ink, varying the thickness of the conductive ink coating by changing the bar coater No. 4 to No. 12 used to coat the conductive ink on the substrate. The results are shown in Figure 3. When conductive ink was applied on top of the released ink, conformability worsened compared to when conductive ink was applied alone. Increasing the thickness of the conductive ink coating improved conformability. Because the surface of the released ink applied to the substrate surface is uneven, if the conductive ink is thin, the conductive ink bonds are likely to break due to the unevenness when stretched, resulting in a decrease in conductivity. On the other hand, if the conductive ink is thick, the conductive ink bonds remain even when stretched, preventing a decrease in conductivity. However, if the conductive ink is applied too thick, it takes a long time for the ink to dry. From these points, it became clear that, taking into consideration the required resistance value and productivity for transport trays or carrier tapes for electronic components, it is preferable that the coating thickness of the conductive ink be within 1.5 to 3.0 times the normal thickness. Normally, bar coater No. 4 is used as the standard coating thickness, but based on the above results, bar coater No. 6 was used as the standard in the following tests.

[0053] Example 1 Desorption ink 1 was printed on a 0.5 mm thick A-PET substrate using a bar coater to a thickness of 2 μm, and then dried for 30 minutes at 60° C. CNT ink was printed on top of the desorption ink 1 using a bar coater as a conductive ink to a thickness of 0.3 μm, and then dried for 30 minutes at 60° C. to prepare a test piece.

[0054] Example 2 A test piece was prepared in the same manner as in Example 1, except that the conductive ink was changed to aniline ink and printed to a thickness of 1.0 μm.

[0055] Example 3 A test piece was prepared in the same manner as in Example 1, except that the substrate was changed to a PP substrate.

[0056] Example 4 A test piece was prepared in the same manner as in Example 1, except that the release ink was changed to release ink 2.

[0057] Example 5 A test piece was prepared in the same manner as in Example 1, except that the release ink was changed to release ink 3.

[0058] Example 6 A test piece was prepared in the same manner as in Example 1, except that the thickness of the conductive ink was changed from 0.3 μm to 0.4 μm.

[0059] Example 7 A test piece was prepared in the same manner as in Example 1, except that the thickness of the conductive ink was changed from 0.3 μm to 0.6 μm.

[0060] Comparative Example 1 A test piece was prepared in the same manner as in Example 1, except that the conductive ink was printed directly on the substrate to a thickness of 0.2 μm without printing the release ink.

[0061] Comparative Example 2 A test piece was prepared in the same manner as in Example 2, except that the conductive ink was printed directly on the substrate to a thickness of 0.67 μm without printing the release ink.

[0062] Comparative Example 3 A test piece was prepared in the same manner as in Example 1, except that the thickness of the conductive ink was changed from 0.3 μm to 0.2 μm.

[0063] Comparative Example 4 A test piece was prepared in the same manner as in Example 1, except that the thickness of the conductive ink was changed from 0.3 μm to 1.2 μm.

[0064] Test pieces of the above-mentioned Examples and Comparative Examples were subjected to tests for release property and tracking property, and productivity was confirmed. The results are shown in Table 2. FIG. 4A is a graph showing the results of the tracking property test for the Examples, and FIG. 4B is a graph showing the results of the tracking property test for the Comparative Examples. Table 3 shows the color difference values ​​measured using a spectrophotometer in the release test for the Examples and Comparative Examples. Table 4 also shows the color difference values ​​measured using a spectrophotometer as a result of evaluation of the recycled pellets.

[0065]

[0066]

[0067]

[0068] Comparative Examples 1 and 2 had good tracking and productivity but no ink release. Furthermore, in the evaluation of recycled pellets, the ink did not release, resulting in a larger color difference compared to recycled A-PET. Comparative Example 3 had good releasability and productivity, but poor tracking. On the other hand, Examples 1 and 2 had good releasability and productivity, and by increasing the thickness of the conductive ink to 1.5 times the standard, tracking also improved. Furthermore, in the evaluation of recycled pellets, the color difference with recycled A-PET was small, suggesting that recycling can be carried out without problems. Examples 3 to 5 also had good releasability, tracking, and printability. In Example 6, the tracking was even better than in Example 1 because the conductive ink thickness was 2.0 times the standard, and in Example 7, the tracking was even better than in Example 6 because the conductive ink thickness was 3.0 times the standard. In Comparative Example 4, the releasability was good, but the tracking ability did not change significantly even though the thickness of the conductive ink was twice as thick as in Example 7. In addition, because the thickness of the conductive ink was too thick, the ink took a long time to dry, which could lead to the risk of cracking, resulting in poor productivity.

[0069] 1 Base layer 2 Conductive ink layer 3 Intermediate layer

Claims

1. A substrate layer which is a plastic sheet; a conductive ink layer provided on at least one side of the substrate layer; and an intermediate layer provided between the substrate layer and the conductive ink layer, which allows the conductive ink layer to be removed in an alkaline solution. The conductive ink layer side has a surface resistance of 1×10 3 ~×1×10 13 A carrier tray or carrier tape for electronic components having a resistance of Ω / □.

2. A carrier tray or carrier tape for electronic parts as described in claim 1, which is a molded product involving the stretching of a laminated sheet of the base material layer, conductive ink layer, and intermediate layer.

3. A transport tray or carrier tape for electronic components as described in claim 1, wherein the thickness of the conductive ink layer is such that when a laminate sheet of the base layer, the conductive ink layer, and the intermediate layer is stretched to a stretch ratio of 2, calculated from the ratio of the thicknesses before and after stretching, the resistance value increase rate of the stretched portion is within 80 times.

4. A transfer tray or carrier tape for electronic components according to claim 1, wherein the intermediate layer contains a resin composition that is swellable or soluble in an alkaline solution.

5. A method for producing a transport tray or carrier tape for electronic components according to any one of claims 1 to 4, comprising a step of stretching and molding a laminated sheet of the base material layer, the conductive ink layer, and the intermediate layer.

6. A method for recycling a carrier tray or carrier tape for electronic components, comprising the steps of: immersing the carrier tray or carrier tape for electronic components described in any one of claims 1 to 4 in an alkaline solution to swell or dissolve the intermediate layer provided between the base layer and the conductive ink layer, and removing at least the conductive ink layer from the carrier tray or carrier tape for electronic components; and recycling the base layer from which the conductive ink layer has been removed, as a molding material.

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