JP2014031287A - Method for processing expanded graphite sheet - Google Patents

Abstract

Provided is a method for processing an expanded graphite sheet, which can easily remove burrs generated when the expanded graphite sheet is punched, and can reduce adhesion of powder generated during the punching process to the expanded graphite sheet. To do.
A processing method of an expanded graphite sheet 1 is that an exfoliated graphite sheet 1 is adhered to one side of the expanded graphite sheet 1 and a blade 9 is caused to enter from a surface 1a on which the exfoliated film 2 is not adhered. The sheet 1 is punched into a predetermined shape, and the re-peeling film 2 is peeled from the punched expanded graphite sheet 1.
[Selection] Figure 1

Description

  The present invention relates to a method for processing an expanded graphite sheet by punching.

  In addition to the inherent properties of graphite, such as heat resistance, chemical resistance, lubricity, thermal conductivity, and electrical conductivity, graphite sheets have properties such as low density, high elasticity, and flexibility. Yes. Therefore, for example, using high elasticity as a sealing material for gaskets and packing, as a release material using lubricity and surface smoothness, as a heat conduction material and heat dissipation material using high thermal conductivity As a sealing material for a conductive connector using electrical conductivity and high elasticity, it is used as a flexible heater using electrical conductivity and flexibility. And according to these various uses, it is processed into various shapes.

  As a processing method of the expanded graphite sheet, punching with high mass productivity is common. By punching the expanded graphite sheet using a punching die such as a Thomson mold or a mold, the outer shape of the expanded graphite sheet can be processed into various shapes according to the shape of the mold. A hole can be drilled.

  However, generation of burrs has been a problem in punching of expanded graphite sheets. In particular, in an expanded graphite sheet having a thickness of 0.5 mm or more, burrs generated by punching are large, and labor and time are required for removing the burrs.

  Further, in the punching process of the expanded graphite sheet, the powder of the expanded graphite sheet generated along with the process adheres to the cut surface and the vicinity thereof. Therefore, conventionally, a cleaning process for removing the adhering powder from the expanded graphite sheet after punching is necessary. This process was performed, for example, by irradiating the expanded graphite sheet after punching with ultrasonic waves in a state immersed in water or alcohol to release the powder, and then drying the expanded graphite sheet (patent) Reference 1). For this reason, a plurality of steps are required for cleaning to remove the powder from the expanded graphite sheet after the punching process, which requires labor and time.

  Therefore, in view of the above situation, the present invention can easily remove burrs generated when punching an expanded graphite sheet, and reduce the adhesion of powder generated during punching to the expanded graphite sheet. An object of the present invention is to provide a method for processing an expandable graphite sheet.

  In order to solve the above-mentioned problems, a method for processing an expanded graphite sheet according to the present invention (hereinafter sometimes simply referred to as “processing method”) is as follows. The blade is advanced from the surface where the release film is not attached, the expanded graphite sheet is punched into a predetermined shape, and the re-release film is released from the punched expanded graphite sheet.

  "Expanded graphite sheet" is a graphite sheet obtained by treating graphite with sulfuric acid, nitric acid, etc. to form an intercalation compound, rapidly heating it to gasify the material between the layers, expanding the layer spacing, and then rolling. .

  The “removable film” is a film that is formed by laminating a pressure-sensitive adhesive on a base film, and can be peeled off after being used after being adhered to an adherend. As the base film, polyethylene such as low density polyethylene, high density polyethylene, linear low density polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polyester, polypropylene, polyvinyl chloride, poly A plastic film such as vinylidene chloride, polymethylpentene, polycarbonate, polyvinyl alcohol, cellulose acetate, polyamide, polyimide, polycarbodiimide, or a film in which a plurality of these plastics are laminated can be used.

  Moreover, as an adhesive laminated on the base film, ethylene vinyl acetate, vinyl acetate, acrylic, styrene acrylic, urethane, epoxy, polyester, cyanoacrylate, polyester, polyvinyl alcohol, It is possible to use an isocyanate-based, natural rubber-based, synthetic rubber-based, silicon-based pressure-sensitive adhesive, or a pressure-sensitive adhesive obtained by mixing these.

  In the re-peeling film, the pressure-sensitive adhesive layer may be laminated on the base film via an intermediate layer such as a layer that imparts elasticity to the re-peeling film.

  As the “blade” for punching the expanded graphite sheet, a Thomson die or a die for punching can be used. Here, the Thomson type has a predetermined groove formed on a wood or resin plate by laser processing, etc., and a metal blade that matches the shape of the groove is embedded in the groove so that the cutting edge protrudes from the groove Type.

  According to the processing method of this structure, a re-peeling film is stuck on the expanded graphite sheet in advance, and the blade is inserted from the surface where the re-peeling film is not stuck to punch the expanded graphite sheet. The burrs that are inevitably generated at the time of punching are generated so as to protrude in the advancing direction of the blade on the cut surface of the expanded graphite sheet, so that the burrs bite into the re-peeling film. Thereby, when peeling a re-peeling film, the burr | flash of the state which bite into the re-peeling film can be removed simultaneously. Therefore, according to the present invention, it is possible to remove burrs without requiring labor and time with a simple operation of only peeling the re-peeling film.

  In addition, the expanded graphite sheet powder generated when the expanded graphite sheet is punched with a blade is near the cut surface and is not the surface into which the blade enters, in other words, the blade that has entered the expanded graphite sheet. It adheres mainly to the surface through which it penetrates. On the other hand, in this invention, since the re-peeling film is previously affixed on the surface where powder tends to adhere, it is prevented that an expanded graphite sheet adheres to this surface. Therefore, unlike the conventional processing method, it is possible to reduce the necessity of a cleaning step for removing the powder from the expanded graphite sheet after punching.

  The processing method of the expanded graphite sheet according to the present invention is as described above, wherein “the re-peeling film is peeled at an angle of 180 degrees from an acrylic plate in which an ethylene vinyl acetate pressure-sensitive adhesive is laminated on a polyethylene base film. It is a film having an adhesive strength of 0.10 N / 25 mm width to 0.15 N / 25 mm width.

  By adopting this configuration, at the stage of punching out the expanded graphite sheet with the blade, the re-peeled film is firmly adhered to the expanded graphite sheet without peeling, and after the punching is finished, the re-peeled film is easily expanded. It can be peeled from the graphite sheet.

  The processing method of the expanded graphite sheet according to the present invention is, in the above-described configuration, "the blade enters only halfway through the thickness of the re-peeling film, and the re-peeling film leaves an uncut portion without being punched". it can.

  According to this configuration, even if the expanded graphite sheet is punched into a predetermined shape and divided into a plurality of portions, the re-peeling film is not punched and is connected at the uncut portion. Thereby, the whole re-peeling film can be easily peeled by a single peeling operation.

  In addition, conventionally, when the expanded graphite sheet is punched with a blade, the generated expanded graphite sheet powder is scattered, so that the scattered powder may contaminate the working environment and remove the scattered powder from the environment. Work was necessary. On the other hand, in this structure, since the re-peeling film exists also in the part from which the expanded graphite sheet was cut, the powder generated by punching adheres to the re-peeling film without scattering. Thereby, contamination of the working environment due to scattering of the powder of the expanded graphite sheet can be prevented. In addition, since the attached powder can be removed by peeling the re-peeling film, the work of removing the powder from the environment becomes unnecessary.

  As described above, as an effect of the present invention, burrs generated when punching an expanded graphite sheet can be easily removed, and adhesion of powder generated during punching to the expanded graphite sheet can be reduced. A method for processing an expanded graphite sheet can be provided.

It is a schematic diagram of the processing method of one Embodiment of this invention. It is a schematic diagram of the punching process of the conventional expanded graphite sheet.

  Hereinafter, the processing method of the expanded graphite sheet 1 which is one Embodiment of this invention is demonstrated using FIG. The processing method of this embodiment includes a step of attaching the re-peeling film 2 to one side of the expanded graphite sheet 1 (referred to as “sticking step”), and the blade 9 from the side where the re-peeling film 2 is not stuck. And a step of punching the expanded graphite sheet 1 into a predetermined shape (referred to as “punching step”) and a step of peeling the re-peeling film 2 from the punched expanded graphite sheet 1 (referred to as “peeling step”). doing. Hereinafter, of the front and back surfaces of the expanded graphite sheet 1, the surface into which the blade 9 enters is referred to as “upper surface 1 a”, and the other surface is referred to as “bottom surface 1 b”.

  More specifically, in the attaching step, the re-peeling film 2 is attached to the bottom surface 1b of the expanded graphite sheet 1 prior to punching the expanded graphite sheet 1 (see FIG. 1 (a)). The processing method of the present embodiment is suitable for processing the expanded graphite sheet 1 having a thickness of 0.1 mm to 2.0 mm, and the expanded graphite having a thickness of 0.5 mm or more that causes a large burr in the conventional processing method. This is particularly effective for processing the sheet 1. Note that FIG. 1 does not accurately illustrate the relationship between the thickness of the expanded graphite sheet 1 and the re-peeling film 2.

  The re-peeling film 2 is a film in which a pressure-sensitive adhesive is laminated on a base film, and is adhered by bringing the pressure-sensitive adhesive layer side into contact with the bottom surface 1 b of the expanded graphite sheet 1. The re-peeling film 2 is required to have a characteristic that it does not peel from the expanded graphite sheet 1 at the stage of punching and can be easily peeled off from the expanded graphite sheet 1 after punching. In this embodiment, the re-peeling film 2 laminated | stacked by the coextrusion method is used using low density polyethylene as a base film and using ethylene vinyl acetate copolymer as an adhesive. Here, the base film has a thickness of 30 μm to 60 μm, and the adhesive layer has a thickness of 10 μm to 20 μm. Moreover, the adhesive strength of the re-peeling film 2 is 0.10 N / 25 mm width to 0.15 N / 25 mm width as the adhesive strength when peeling from the acrylic plate at an angle of 180 degrees.

  Next, in the punching step, the blade 9 is entered from the upper surface 1a side where the re-peeling film 2 is not adhered to the expanded graphite sheet 1, and the expanded graphite sheet 1 is punched into a predetermined shape (FIGS. 1A and 1B). )reference). At this time, the penetration of the blade 9 is limited to the middle of the thickness of the re-peeling film 2, and the re-peeling film 2 is not punched and leaves an uncut portion 2a. In FIG. 1, a case where a Thomson type is used as the blade 9 is illustrated.

  By the above punching process, the expanded graphite sheet 1 is punched into a predetermined shape according to the shape of the blade 9, and a burr 11 is generated in the vicinity of the cut surface. Since the burr 11 is generated in the traveling direction of the blade 9 at the time of punching, it protrudes from the bottom surface 1b side end portion of the cut surface and bites into the re-peeling film 2 attached to the bottom surface 1b of the expanded graphite sheet 1 (FIG. 1 ( b)). In the cut surface obtained by punching, generally, the corner portion formed when the blade 9 first enters is smoothly curved, and the flat portion formed by shearing as the blade 9 further advances. Further, the non-uniform surface formed by peeling off the workpiece material continues to the burr 11, but the shape of the cut surface is not shown in FIG.

  In the conventional punching process in which the re-peeling film 2 is not attached to the expanded graphite sheet 1, as shown in FIG. 2B, the powder 12 of the expanded graphite sheet 1 generated in the punching process is a cut surface and its vicinity. Adhere to. At this time, the powder 12 adheres mainly to the vicinity of the burr 11 on the bottom surface 1 b of the expanded graphite sheet 1. On the other hand, in the processing method of this embodiment, since the re-peeling film 2 is stuck on the bottom surface 1b of the expanded graphite sheet 1, the powder 12 does not adhere to the bottom surface 1b.

  Moreover, in the conventional punching process in which the re-peeling film 2 is not adhered to the expanded graphite sheet 1, as shown in FIG. 2B, the powder 12 of the expanded graphite sheet 1 generated in the punching process is scattered. . On the other hand, in the processing method of this embodiment, the re-peeled film 2 attached to the bottom surface 1b of the expanded graphite sheet 1 is connected by the uncut portion 2a without being punched, and the expanded graphite sheet 1 is cut. The re-peeling film 2 exists also in the part. Thereby, as shown in FIG.1 (b), the powder 12 which generate | occur | produced at the punching process of the expanded graphite sheet 1 adheres to the re-peeling film 2 without scattering. Therefore, the possibility that the work environment is contaminated by the scattered powder 12 can be reduced. In FIGS. 1 and 2, the sizes of the burr 11 and the powder 12 are exaggerated.

  In the peeling step, the re-peeling film 2 is peeled from the expanded graphite sheet 1. As a result, the burrs 11 biting into the re-peeling film 2 are removed together with the re-peeling film 2. Therefore, the burr 11 inevitably generated in the punching process can be removed without requiring labor and time by a simple operation only by peeling the re-peeling film 2.

  In addition, the powder 12 of the expanded graphite sheet 1 adhering to the re-peeling film 2 is also removed together with the re-peeling film 2. Thereby, the powder 12 inevitably generated in the punching process can be removed without requiring labor and time by a simple operation of simply peeling the re-peeling film 2.

  Moreover, since the re-peeling film 2 is connected by the uncut portion 2a without being punched, even if the expanded graphite sheet 1 is punched and divided into a large number of portions, the entire re-peeling film 2 can be obtained by a single operation. Can be peeled from the expanded graphite sheet 1.

  Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the above-described embodiments, and various improvements and design changes can be made without departing from the scope of the present invention. It is.

  For example, in the above embodiment, the Thomson type is illustrated as the blade for punching the expanded graphite sheet. However, the present invention is not limited to this, and a punching die can be used.

  Further, in the above embodiment, the case where the expanded graphite sheet is a single layer is illustrated by way of illustration, but the present invention is not limited to this, and a laminated type expanded graphite sheet in which a plurality of expanded graphite sheets are bonded via a binder. In contrast, the present invention can be applied.

DESCRIPTION OF SYMBOLS 1 Expanded graphite sheet 2 Removable film 2a Uncut part 9 Blade 11 Burr 12 Powder

JP 2009-51730 A

Claims (3)

A re-peeling film is stuck on one side of the expanded graphite sheet, a blade is entered from the side where the re-peeling film is not stuck, and the expanded graphite sheet is punched into a predetermined shape. A method for processing an expanded graphite sheet, characterized by peeling. The re-peeling film has a polyethylene base film laminated with an ethylene vinyl acetate pressure-sensitive adhesive, and has an adhesive strength when peeled from an acrylic plate at an angle of 180 degrees from 0.10 N / 25 mm width to 0.15 N / The expanded graphite sheet processing method according to claim 1, wherein the expanded graphite sheet is a 25 mm wide film. The method for processing an expanded graphite sheet according to claim 1 or 2, wherein the penetration of the blade is stopped halfway through the thickness of the re-peeled film, and the re-peeled film is left uncut without being punched out.

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