JP5757181B2 - Method for producing metallized film - Google Patents

Description

The present invention relates to a method for manufacturing metallized film constituting a metallized film capacitor.

  A conventional metallized film capacitor formed by winding a metallized film or a laminated metallized film capacitor formed by laminating a metallized film has internal electrodes (metallized film pillars) of the metallized film wound or laminated. A metal sprayed part (or metallicon, metallized electrode) is formed on the two electrode extraction surfaces at both ends of the body, and an external lead terminal is soldered to these two metal sprayed parts.

  The internal electrode of the metallized film capacitor is formed by vapor-depositing a metal such as aluminum or zinc on one side of a dielectric film made of polypropylene (PP) or polyvinylidene fluoride (PVDF). The dielectric film is damaged by the heat of the film, the film is deformed by being heated under tension to run the film, or the film generates gas and is taken into the deposited film. Therefore, vapor deposition is performed while cooling the dielectric film. In addition, Patent Document 1 discloses a method for manufacturing an internal electrode of a metallized film capacitor by performing metal vapor deposition while cooling a dielectric film.

  However, when vapor deposition is performed on one side of the dielectric film while cooling the dielectric film, the deposited metal often grows in an island shape. And when a vapor deposition metal grows in island shape, the film thickness required for conduction | electrical_connection increases, and since many grain boundaries and lattice defects exist, it will become a thing with high electrical resistivity. This is because in the vacuum deposition method, atoms evaporated from the molten metal adhere to the dielectric film that is the base material and deposit to form a deposited film, but the atoms that arrive at the dielectric film are subject to the substrate temperature. As a result, the deposited metal G is formed in an island shape (island block GM) on the surface of the substrate F cooled by the cooling roll CR as shown in FIG. 5a. Presumed to grow. Then, as shown in FIG. 5b, in the deposited layer K of vapor deposited metal deposited between the island blocks GM, recovery of grain boundaries and lattice defects and recrystallization hardly occur, and the deposited film has many lattice defects and grain boundaries. It will be included. Such lattice defects and crystal grain boundaries are conspicuous at the time of cooling vapor deposition, but there are not a few defects in the vapor deposition film even when it is not cooled or when vapor deposition is performed with weak cooling.

  As described above, when the deposited film includes lattice defects and crystal grain boundaries, the electrical resistivity increases and heat is generated. It has been found that 90% or more of the calorific value of the film capacitor is due to the contribution from the vapor deposition film constituting the internal electrode. For this reason, it is necessary to reduce the resistance of the vapor deposition film.

  It is common for those skilled in the art to reduce the resistance of the deposited film by increasing the thickness of the deposited film.

  However, it is inevitable that the thickness of the vapor deposition film increases the size of the capacitor, so that the size cannot be reduced and the material cost also increases.

JP 2009-224444 A

The present invention has been made in view of the above-mentioned problems, and is intended to reduce the grain interfacial area in the deposited film deposited on the surface of the dielectric film and repair the lattice defects, thereby reducing the metal resistivity of the metalized film capacitor. It aims at providing the manufacturing method of the metallized film which comprises this internal electrode.

  In order to achieve the above object, a method for producing a metallized film according to the present invention comprises producing a metallized film comprising a dielectric film constituting a metallized film capacitor and an internal electrode layer disposed on the surface of the dielectric film. In this method, a metal is vapor-deposited on the surface of the dielectric film to form a metal vapor-deposited film, and a working strain is introduced into the crystal of the metal vapor-deposited film by cold working, and the dielectric film and the working strain are introduced. A first step for producing an intermediate comprising a metal vapor-deposited film; heat treating the intermediate; recrystallizing at least a portion of the metal vapor-deposited film to form an internal electrode layer; and a metal comprising a dielectric film and an internal electrode layer It consists of the 2nd step which manufactures a chemical film.

  The method for producing a metallized film according to the present invention is a method for producing a metallized film serving as an internal electrode constituting a metallized film capacitor. The metallized film is deposited while cooling the dielectric film. In order to eliminate the lattice defects and grain boundaries of the deposited metal film, which are thought to be caused by abrupt cooling on the film surface, cold work is performed to introduce work strain into the deposited metal, which is then heat treated. As a result, it is possible to recrystallize the deposited metal, repair defects generated during the metal deposition, and enlarge the crystal grains. If recrystallization is not applied with processing strain, the driving force for recrystallization is weak, and therefore the temperature needs to be raised. However, when the temperature is raised, the film may be damaged. On the other hand, since the effect is small even if heat treatment for recrystallization is performed without imparting processing strain, it is essential to impart processing strain in order to recrystallize while avoiding thermal damage to the dielectric film.

  When the metal is deposited on the surface of the dielectric film in the first step, the dielectric film is placed on a cooling roll of, for example, about several tens of degrees Celsius so that the dielectric film is not damaged by the heat during the deposition. Metal deposition is carried out while transporting.

  Here, the dielectric film can be formed from polypropylene (PP), polyvinylidene fluoride (PVDF), polyphenylene sulfide (PPS), or the like, and a metal such as molten aluminum or zinc is deposited on the surface of the dielectric film.

  Once the metal is deposited on the surface of the dielectric film, the metal is further continuously conveyed. For example, cold working is performed through the dielectric film and the metal deposited on the surface between the upper and lower rolling rolls. Processing strain is introduced into the crystal to form a metal vapor-deposited film, and an intermediate composed of a dielectric film and a metal vapor-deposited film is produced.

  Next, in the second step, the intermediate produced in the first step is heat-treated, and a metallized film (internal electrode) comprising a dielectric film and an internal electrode layer is formed by using a metal vapor deposition film as an internal electrode layer. To manufacture.

  Here, in the second step, it is not always necessary that the metal is recrystallized completely. Even if the recrystallization is incomplete, the internal electrode layer is formed with a part of the recrystallization. Can be done. Needless to say, it is preferable that the metal is recrystallized completely.

  Here, as an embodiment of the heat treatment in the second step, the following two forms can be mentioned.

  One of them is a method in which the intermediate is placed in a heating furnace having a temperature higher than the recrystallization temperature of the metal and lower than the melting point of the dielectric film, and heat treatment is performed. After the intermediate is placed in the heating furnace, a predetermined temperature is preferably maintained until recrystallization is completed.

  The other method is a method in which heat treatment is performed by energizing the metal vapor deposition film to cause self-heating. For example, the intermediate produced in the first step is wound up into a roll shape, and both ends thereof are sandwiched between metal plates and energized. The metal vapor deposition film is recrystallized by Joule heat generated during the energization.

  The time required for recrystallization varies depending on the temperature condition, rolling rate, and the like maintained at a high temperature, and the higher the temperature and the higher the rolling rate, the shorter the time until recrystallization is completed. However, as described above, it is not always necessary to perform recrystallization completely, and it is sufficient that recrystallization is achieved to the extent that a desired resistivity is obtained.

  According to the method for producing a metallized film of the present invention described above, the metallization for forming the internal electrode having a low electric resistance can be achieved by eliminating the defects of the metal particles generated in the process of depositing the metal particles while cooling the dielectric film. A film can be produced.

  The present invention also extends to a metallized film, which is a metallized film comprising a dielectric film constituting a metallized film capacitor and an internal electrode layer disposed on the surface of the dielectric film. A film in which the internal electrode layer has a recrystallized structure of a deposited metal deposited on the surface of the dielectric film.

  The internal electrode layer has a recrystallized structure of the deposited metal deposited on the surface of the dielectric film, so that defects generated during metal deposition are repaired, resulting in large crystal grains and a reduced grain interface area. Thus, a metalized film capacitor having a low electric resistivity is obtained.

  As can be understood from the above description, according to the method for producing a metallized film of the present invention, after metal is deposited on the surface of the dielectric film, this is cold worked to introduce work strain into the deposited metal, and then heat treatment is performed. By recrystallizing the deposited metal, the lattice defects generated when the deposited metal is deposited on the surface of the dielectric film can be repaired, and the grain boundary area can be reduced. A metallized film used for a low-performance, high-performance metallized film capacitor can be produced.

It is a schematic diagram explaining the 1st step of the manufacturing method of the metallized film of this invention. (A), (b) is both the schematic diagrams explaining embodiment of a 2nd step. It is a schematic diagram explaining the manufactured metallized film. It is a longitudinal cross-sectional view explaining the metallized film capacitor which uses a metallized film for an internal electrode. It is a schematic diagram explaining the manufacturing method of the conventional metallized film.

  Hereinafter, embodiments of the method for producing a metallized film of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram for explaining a first step of the method for producing a metallized film of the present invention, and FIGS. 2a and 2b are schematic diagrams for explaining an embodiment of the second step.

  In the illustrated manufacturing method, as a first step, the dielectric film 1 wound around the winding roll MR1 is unwound by rotating the winding roll MR1 (X1 direction), and the dielectric film is unwound. In the process of transporting 1, the vacuum container SY in which the vapor deposition apparatus DP is accommodated is passed (X2 direction).

  Here, the dielectric film 1 is formed from polypropylene (PP), polyvinylidene fluoride (PVDF), polyphenylene sulfide (PPS), or the like.

  In the vacuum vessel SY, a deposited metal 2 ″ such as aluminum or zinc melted from the deposition apparatus DP is deposited on the lower surface of the dielectric film 1 to be transported.

  In the vacuum vessel SY, the deposited metal 2 ″ is deposited while being cooled by a cooling roll CR (adjusted to a temperature of about minus several tens of degrees Celsius) where the upper surface of the dielectric film 1 rotates in the transport direction (X3 direction). It is.

  The dielectric film 1 that has passed through the vacuum vessel SY and on which the vapor-deposited metal 2 ″ has been deposited is then rolled in the process of passing through a pair of upper and lower rotatable (X4 direction) rolling rolls FR, FR.

  In this rolling process, the rolling roll FR is adjusted to a temperature of 25% or less of the melting point of the vapor-deposited metal 2 ″, and the dielectric film 1 and the vapor-deposited metal 2 deposited on its surface in the process of passing through the rolls FR and FR. "Is cold worked. By this cold working, working strain is introduced into the crystal of the deposited metal 2 ″.

  The temperature in the vacuum vessel SY is also preferably adjusted to a temperature of 25% or less of the melting point of the vapor deposition metal 2 ″.

  For example, when the vapor deposition metal 2 ″ is aluminum, its melting point is 933K, so the temperature in the vacuum vessel SY during vapor deposition and the temperature of the rolling roll FR during cold working are about 233K (−40 ° C.). Adjusted to

  By being cold-worked, an intermediate body 3 made of a dielectric film 1 and a metal vapor-deposited film 2 ′ formed by rolling on the surface thereof is manufactured, and this intermediate body 3 is wound up by a winding roll MR2. (X5 direction).

  Next, the process proceeds to the second step. This second step has two methods shown in FIGS. 2a and 2b.

  In one embodiment of the second step, as shown in FIG. 2a, the intermediate 3 is placed in a heating furnace TR not lower than the metal recrystallization temperature and not higher than the melting point of the dielectric film, and heat-treated with a heater. (Heat heat H) to recrystallize the metal vapor-deposited film 2 ′, and as shown in FIG. 3, the internal electrode layer 2 is formed from the metal vapor-deposited film 2 ′, and the internal electrode layer is formed on the surface of the dielectric film 1. The metallized film 4 in which 2 is laminated is manufactured. Here, when the metal is 99.999% purity aluminum, the recrystallization temperature is about 80 ° C., and when the dielectric film is PP, the melting point is about 165 ° C. Therefore, when these materials are applied A heat treatment temperature of about 80 ° C. or higher and 165 ° C. or lower is applied.

  Here, the time required for recrystallization in the heating furnace TR differs depending on the temperature conditions in the heating furnace TR, the rolling rate during cold working, etc., but the recrystallization does not necessarily have to be performed completely. Recrystallization should just be achieved to such an extent that the internal electrode layer 2 having a desired electrical resistivity can be obtained.

  On the other hand, as shown in FIG. 2b, another embodiment of the second step is a method in which both ends of the rolled intermediate body 3 are sandwiched between metal plates S, S, and this energization is performed. The metal deposition film 2 ′ is recrystallized by self-heating (Joule heat) at the time to form the internal electrode layer 2, and the metallized film 4 is manufactured.

  The internal electrode layer 2 constituting the metallized film 4 shown in FIG. 3 is recrystallized due to the introduction of processing strain in the first step and the heat treatment in the second step due to lattice defects formed in the deposited metal during metal deposition. The internal electrode layer 2 is repaired by the conversion and has an extremely low electrical resistivity.

  FIG. 4 shows a metallized film capacitor 10 constructed using the metallized film 4 produced by the production method shown in FIGS.

  The metallized film capacitor 10 shown in the figure includes a metallized film column 5 in which a metallized film 4 is wound, and metal sprayed portions 7 and 7 (metallicon electrodes) formed on two electrode extraction surfaces at both ends thereof. The external spraying terminals 8b and 8b (bus bars) connected to the metal sprayed portions 7 and 7 via the solder layers 8a and 8a, the case 9a for accommodating them, and the metallization formed in the case 9a. It is generally composed of a mold resin body 9b in which the film column 5 is embedded.

  A specific configuration of the metallized film column 5 is as follows. The internal electrode layer 2 is formed on one side surface of the dielectric film 1 to form a metallized film 4, and two metallized films 4 are laminated. (Two pairs of metallized films), and the two pairs of metallized films 4 are wound.

  Here, the internal electrode layer 2 formed on one side surface of one dielectric film 1 of the set of metallized films 4 has one end along the longitudinal direction thereof in close contact with one metal sprayed portion 7, The other end along the longitudinal direction is provided with an insulation margin m (see FIG. 3) of about 2 mm, for example, so as to be insulated from the other metal sprayed portion 7. Further, the end portion of the internal electrode layer 2 that is in close contact with the metal sprayed portion 7 is a so-called heavy edge h (see FIG. 3) that is thicker than other portions in order to ensure electrode contact. For example, when the general part of the metal vapor-deposited film is about 30 nm, the heavy edge is adjusted to about double 60 nm.

  An outer film 6 made of polyethylene terephthalate (PET) or the like is wound around the metallized film column 5 other than the electrode lead-out surface, for example, several tens of times to cover the peripheral surface.

  The metallized film capacitor 10 shown in the figure is a high-performance metallized film capacitor because the electrical resistivity of the internal electrode layer 2 that is a constituent member thereof is extremely low.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Dielectric film, 2 ... Internal electrode layer, 2 '... Metal vapor deposition film, 2 "... Metal vapor deposition, 3 ... Intermediate, 4 ... Metallized film, 5 ... Metallized film pillar, 6 ... Exterior film, 7 ... Metal sprayed portion (metallicon electrode), 8a ... solder layer, 8b ... external lead terminal (bus bar), 9a ... case, 9b ... molded resin body, 10 ... metallized film capacitor

Claims (2)

A method for producing a metallized film comprising a dielectric film constituting a metallized film capacitor and an internal electrode layer disposed on the surface of the dielectric film,
The metal film is vapor-deposited on the surface of the dielectric film to form a metal vapor-deposited film, which is composed of the dielectric film and a metal vapor-deposited film in which the work strain is introduced by introducing a work strain into the crystal of the metal vapor-deposited film by cold working. A first step of producing an intermediate;
A metallized film consisting of a dielectric film and an internal electrode layer is formed by conducting a heat treatment to energize the self-heating of the metal deposited film constituting the intermediate and recrystallizing at least a part of the deposited metal film as an internal electrode layer. The manufacturing method of the metallized film which consists of a 2nd step which manufactures. The method for producing a metallized film according to claim 1 , wherein in the second step, recrystallization of the metal is completely performed to form an internal electrode layer.

Images