JP2009181938A - Plastic film static eliminator and heating carrier device for plastic film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a static eliminator capable of easily eliminating static electricity of a plastic film charged with the static electricity while it is conveyed, and to provide a heating carrier device with the same. <P>SOLUTION: In a vacuum vessel with a vacuum exhaust means 3c, a plastic film static eliminator eliminates static electricity which is charged on a plastic film F while carrying that F in roll to roll toward a take-up device 8 from a winding-off device 6. In the vicinity of a take-up part of the take-up device 8, a gas blow-off means 10 for blowing off gas toward the plastic film in the vacuum vessel which is vacuumed, is provided. During static elimination, the pressure inside the vacuum vessel is preferably set with an absolute pressure from 1.33 Pa to 1.33 kPa (1×10<SP>-2</SP>Torr to 10 Torr). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a plastic film static eliminator that neutralizes charges charged on a plastic film, and a plastic film heating and conveying apparatus including the same.

  Polyimide has excellent heat resistance, and is not inferior to other plastic materials in mechanical, electrical and chemical properties. For example, printed wiring board (PWB), flexible printed wiring board (FPC) It is widely used as an insulating substrate material for electronic parts such as tape automatic bonding tape (TAB) and chip-on-film (COF). Such PWB, FPC, TAB, and COF can be obtained by processing a metal-coated polyimide substrate in which at least one surface of a polyimide film is mainly coated with copper as a metal conductor layer.

  Metal-coated polyimide substrates include a three-layer copper polyimide substrate obtained by bonding a polyimide film and a copper foil via an adhesive, and a two-layer copper polyimide substrate obtained by directly forming a copper layer on the polyimide film. In addition, for a two-layer copper polyimide substrate, a casting substrate in which polyimide is formed on a commercially available copper foil, a method of performing electroplating after sputtering on a commercially available polyimide film, and / or electroless plating on a commercially available polyimide film. There is a two-layer copper polyimide substrate by a plating method in which metals are directly laminated by a method.

  Recently, metal-coated polyimide substrates have been widely used as TAB and COF materials for large liquid crystal panels used for liquid crystal monitors and the like in addition to notebook PCs. On the other hand, as these electronic devices become smaller and thinner, TAB and COF are also required to be smaller and thinner, that is, higher density. As a result, the wiring pitch (wiring width / space width) is becoming narrower, but with the two-layer copper polyimide substrate by the above plating method, the thickness of the polyimide film or conductor layer (copper coating) can be reduced or the thickness can be freely set. Since it can be controlled, it has been attracting particular attention.

  By the way, the manufacturing process of the two-layer copper polyimide substrate by the said plating method includes the process of processing a polyimide film in a vacuum. In general, the vacuum treatment process includes a film drying process, a plasma treatment process, and a sputtering film formation process. While the polyimide film is conveyed from the unwinding roller to the take-up roller by a roll-to-roll, Processed in the process.

  The polyimide film conveyed by roll-to-roll may be charged with static electricity due to friction with the roller. In particular, as the polyimide film becomes thinner, wrinkles occur in the polyimide film due to electrostatic charging, defects occur in the polyimide film due to electrostatic discharge from the polyimide film, scratches occur on the polyimide film, It has been found that there is a high possibility that various problems such as entanglement in a roll will occur.

  Conventionally, when static electricity charged on a plastic film is removed in a vacuum, a self-discharge that discharges the corona discharge at the tip of the brush by bringing a grounded thin brush-like conductive material close to the film to be removed. In other words, a static electricity removal device is used, or a voltage application static electricity removal device such as an alternating current type or a direct current type is employed that applies a high voltage to a needle-like electrode brought close to a film to generate a corona discharge. In addition, a plasma static eliminator, an ultraviolet static eliminator, a soft X-ray static eliminator, and the like are sometimes used.

  The principle of static elimination of the conventional static eliminator using the above corona discharge is to generate positive or negative ions by corona discharge at the electrodes, and charge the ions of the opposite polarity to the polarity of the electrostatic charge of a charged body such as an insulating sheet. The static electricity of the charged body is neutralized by being attracted by an electric field caused by the charge of the body.

  For example, Japanese Patent Publication No. 05-015040 (Patent Document 1) discloses a film static elimination method and a static elimination apparatus for neutralizing a charged body such as a plastic film that travels while traveling using corona discharge. This technique is characterized by performing neutralization in two stages of high-frequency neutralization and direct current neutralization and feedback control of the direct current neutralizer in order to eliminate reverse charging due to excessive neutralization.

  Specifically, after the charged traveling object is neutralized by high-frequency corona discharge with a high-frequency static eliminator, the residual potential and polarity of the traveling object after the high-frequency neutralization is detected by a potential detector, and the detected residual By automatically controlling the DC static eliminator according to the electric potential and polarity, the DC static eliminator generates a DC corona discharge having a polarity opposite to the residual potential and strong enough to cancel the residual potential. is doing.

  However, some types of plastic film, which is an insulating sheet, have high surface resistivity and volume resistivity. Due to the discharge, invisible and very complicated charged patterns composed of innumerable small positive and negative charged portions mixed randomly are formed on both the front and back surfaces of the plastic film according to the discharge mode. In such a case, the electric lines of force close in the charged parts with different polarities, so the electric field becomes very weak at a position slightly away from the charged body, and ions necessary for static elimination cannot be attracted. In some cases, the charge on the insulating sheet cannot be neutralized.

  On the other hand, in Japanese Patent Application Laid-Open No. 07-263173 (Patent Document 2), an ion attracting electrode having a surface extending in a traveling direction of a charged body such as a traveling film and a direction orthogonal thereto is used for generating positive and negative ions. Place the charged object across the charge removal electrode, and alternately or simultaneously generate positive and negative ions from the positive and negative ion generation charge removal electrode, alternately applying high voltage with positive and negative polarity to the ion attraction electrode, There has been disclosed a static elimination method and a static elimination apparatus characterized in that positive and negative ions generated by a static elimination electrode for generating positive and negative ions are attracted by an ion attraction electrode to forcibly irradiate a charged object.

  In addition to inducing a potential in the charged body, this technology ensures that negative ions react positively in the positively charged part and positive ions react in the negatively charged part. Even if the surface of the charged body is microscopically neutralized by a complicated charging pattern formed by innumerable small positive and negative charged portions, the positive and negative charged portions can be separately and strongly charged. In addition, since the ion attracting electrode has a surface that extends in the traveling direction of the charged object and the direction orthogonal thereto, local unevenness in the ion attracting force does not occur, and positive and negative ions are equally attracted. As a result, it is possible to reduce static electricity unevenness.

Japanese Patent Publication No. 05-015040 JP 07-263173 A

  However, the techniques related to static elimination described in Patent Documents 1 and 2 are limited in the degree of vacuum that can be used, and thus may not be applied to a vacuum processing step for producing a metal-coated polyimide substrate. Furthermore, since the static elimination apparatus of patent document 1 and 2 is complicated in apparatus structure and control, it was difficult to use it simply.

  In view of the above-described problems of the prior art, the present invention provides a plastic film static eliminator capable of easily removing static electricity charged on a plastic film conveyed by roll-to-roll while conveying the film, and the same It aims at providing the heating conveyance apparatus for plastic films provided with.

  The inventor paid attention to how charging occurs when transporting a plastic film, and measured the surface potential of the polyimide film using a surface potential meter installed on each of the unwinding side and the winding side of the polyimide film. However, it was found that the surface potential of the polyimide film was almost zero after the plasma treatment step and after the sputtering film formation step. This is because in the plasma treatment process and the sputtering film forming process, there are positively charged particles and negatively charged particles in the plasma space, so even though the polyimide film is charged, it passes through the plasma space. This is presumed to be because the charge is eliminated during the period.

  On the other hand, when the polyimide film is transported in a vacuum where there is no plasma space as in the film drying step, it has been found that once the surface of the polyimide film is charged, it cannot be easily removed. That is, in the drying process in which no plasma space exists, it is considered that the above-described problems caused by the charging of the polyimide film are particularly likely to occur.

  Furthermore, the present inventor found that there was a correlation between the degree of vacuum and the surface potential of the charged plastic film when trying many experiments regarding charging when transporting the plastic film. Therefore, a detailed study was repeated, and a take-up device and a take-up device for transporting a plastic film by roll-to-roll were provided in a vacuum vessel equipped with a vacuum pump for evacuating the entire vacuum vessel. In the vicinity of the device, a gas blowing device capable of blowing gas toward the plastic film was provided.

  Under such a configuration, first, the surface of the plastic film was charged in a state where the inside of the vacuum vessel was kept at atmospheric pressure and the conveyance of the plastic film was stopped. Thereafter, the conveyance of the plastic film was started, the inside of the vacuum vessel was evacuated while blowing gas from the gas blowing device to the film, and the relationship between the pressure in the vacuum vessel and the surface potential of the film was measured.

  As a result, as shown in FIG. 1, it was found that the surface potential of the film approaches zero as the pressure in the vacuum vessel decreases due to exhaust. In this way, while maintaining the pressure in the vacuum vessel within a specific range of vacuum, by blowing out gas to the plastic film in the vacuum vessel, it is effective without leaving almost any static electricity charged in the plastic film. The present inventors have found that it is possible to remove static electricity and have arrived at the present invention.

  In other words, the plastic film static eliminator provided by the present invention is charged on the plastic film while transporting the plastic film by roll-to-roll from the unwinding device to the winding device in a vacuum vessel equipped with a vacuum exhaust means. A plastic film static eliminator for eliminating static electricity, having a gas blowing means introduced from the outside of the vacuum vessel in the vicinity of the winding portion of the winding apparatus, and vacuum drawn by the gas blowing means It is characterized by discharging electricity by blowing gas toward the plastic film in the container.

As is clear from FIG. 1, the plastic film static eliminator has an absolute pressure of 1.33 Pa to 1.33 kPa (1 × 10 ⁻² Torr to 10 Torr) when discharging the gas by discharging gas. ) Is preferable.

  Further, the present invention provides a plastic film heating / conveying device in which a plastic film is taken up in a winding chamber provided in a winding chamber from a winding device provided in the unwinding chamber in a vacuum vessel provided with a vacuum exhaust means. A plastic film static eliminator is provided that removes static electricity that is dried in a drying chamber equipped with a heating device and charged on the plastic film while being conveyed toward the apparatus while being conveyed. The plastic film static eliminator has a gas blowing means for blowing out gas introduced from the outside of the vacuum vessel toward the plastic film in a evacuated winding chamber.

In the above-mentioned plastic film heating and conveying apparatus, as is clear from FIG. 1, the pressure in the take-up chamber is 1.33 Pa to 1.33 kPa (1 × 10 ^{−2) in} absolute pressure when the gas is discharged by discharging the gas. Torr to 10 Torr) is preferable.

  According to the present invention, when a plastic film is transported by roll-to-roll, static electricity charged on the plastic film can be almost eliminated while transporting, and the charge generated during transport of the plastic film can be eliminated. It has become possible. Further, since the gas blown out toward the plastic film is quickly exhausted out of the vacuum container after the charge of the plastic film is removed, it does not adversely affect the drying process of the plastic film.

  The plastic film static eliminator of the present invention conveys the plastic film charged with static electricity on the plastic film conveyed by roll-to-roll from the unwinding device to the winding device in a vacuum vessel equipped with a vacuum exhaust means. While neutralizing the static electricity. This plastic film static eliminator has a gas blowing means for blowing out a gas introduced from the outside of the vacuum container toward the plastic film in the vacuumed vacuum container. The arrangement of the gas blowing means is not particularly limited, but in the vicinity of the unwinding portion of the unwinding device, that is, the position immediately after the plastic film is unwound by the unwinding device, or in the vicinity of the winding portion of the winding device. That is, the plastic film can be disposed at a position immediately before being wound up by the winding device.

  The above plastic film static eliminator can be applied to, for example, a plastic film heating and conveying apparatus. The heat transfer device for plastic film rolls to roll the plastic film from the unwinding device provided in the unwinding chamber toward the winding device provided in the unwinding chamber in the vacuum vessel provided with the vacuum exhaust means. In the drying chamber having a heating device disposed between the unwinding chamber and the winding chamber, the substrate is dried. The plastic film static eliminator provided in the plastic film heating / conveying device has a gas blowing means for blowing out the gas introduced from the outside of the vacuum vessel toward the plastic film in the evacuated unwinding chamber or the winding chamber. Have.

The pressure in the vacuum container to be evacuated, for example, in the case of a plastic film heating and conveying apparatus, the pressure in the winding chamber is 1.33 Pa to 1.33 kPa (1 ×) in absolute pressure when the gas is discharged by discharging the gas. 10 ⁻² Torr to 10 Torr) is preferable.

  Next, the plastic film static eliminator of the present invention will be described below with reference to FIG. 2, taking as an example a plastic film heating / conveying device to which it is specifically applied.

  FIG. 2 shows a schematic view of the plastic film heating and conveying apparatus 20. The plastic film heating / conveying device 20 includes a drying chamber 1a located in the center, and an unwinding chamber 1b and a winding chamber 1c disposed on both sides of the drying chamber 1a. The drying chamber 1a, the unwinding chamber 1b, and the winding chamber 1c are partitioned by the partition plate 2 so that substantially individual vacuum degrees can be maintained.

  The partition plate 2 is provided with an opening 2a through which a plastic film F conveyed by an unwinding device 6 and a winding device 8 described later passes. The drying chamber 1a, the unwinding chamber 1b, and the winding chamber 1c are provided with evacuation means 3a, 3b, and 3c such as a vacuum pump, respectively. As a result, the drying chamber 1a, the unwinding chamber 1b, and the winding chamber 1c are each evacuated to a predetermined degree of vacuum. The drying chamber 1a, the unwinding chamber 1b, and the winding chamber 1c may be provided with pressure measuring devices 4a, 4b, and 4c such as pressure gauges for measuring the degree of vacuum in the chamber.

  A heating device 5 is provided in the drying chamber 1a. The heating device 5 has heating means 5 a and 5 b such as heaters facing each other so as to sandwich the front and back of the plastic film F conveyed from the unwinding device 6. Thereby, the plastic film F is continuously heat-dried under vacuum. A temperature measuring device (not shown) such as a thermocouple may be provided in the vicinity of the heating device 5. Thereby, it becomes possible to control the heating temperature of the heating apparatus 5 appropriately.

  The unwinding chamber 1b is provided with an unwinding device 6 such as an unwinding roller that is rotatable about the rotation shaft. The plastic film F unwound from the unwinding device 6 is conveyed toward the drying chamber 1a through the guide rollers 7a and 7b. On the other hand, the take-up chamber 1c is provided with a take-up device 8 such as a take-up roller that is rotatable about the rotation axis. The plastic film F, which has been dried in the drying chamber 1a and then conveyed through the guide rollers 9a and 9b, is wound on the winding device 8. With these configurations, the plastic film F is continuously dried in the vacuumed drying chamber 1a while being conveyed from the unwinding device 6 to the winding device 8 by roll-to-roll.

  As shown in FIG. 2, the plastic film heating and conveying apparatus 20 is provided with a gas blowing means 10 in a winding chamber 1c that is evacuated by a vacuum exhausting means 3c. The gas introduced from the outside through the 20 container walls is blown out to the plastic film F. Specifically, the gas blowing means 10 is configured to supply gas from a gas supply source (not shown) to a gas blowing unit 10a such as a nozzle that blows gas toward the plastic film F passing through the gas blowing unit 10a. A gas supply line 10b to be supplied and a valve 10c for adjusting a gas flow rate provided on the gas supply line 10b are provided. In addition, although the kind of gas used for the above-mentioned blowing is not specifically limited, inert gas, such as helium, argon, nitrogen, is preferable.

When discharging with the plastic film discharging device, the pressure in the space where the gas is blown out, for example, as shown in FIG. 2, when gas is blown out in the winding chamber 1c, The absolute pressure is preferably 1.33 Pa to 1.33 kPa (1 × 10 ⁻² Torr to 10 Torr) in absolute pressure. By controlling the pressure within this range, it is possible to perform static elimination more effectively as can be seen from FIG. The above pressure control is performed by adjusting the amount of gas released toward the plastic film F, for example, by adjusting the opening of the valve 10c, the exhaust amount of the vacuum exhaust means 3c, and the like. Can do.

  The gas released toward the plastic film F is preferably discharged to the outside immediately after the charge on the surface of the plastic film F is removed. Thereby, the influence which it has on a drying process can be suppressed. For example, when gas is blown out in the take-up chamber 1c, the gas is sucked using the vacuum exhaust means 3c provided in the take-up chamber 1c and quickly discharged to the outside of the take-up chamber 1c. It is preferable. Thereby, since the gas released into the winding chamber 1c is less likely to enter the drying chamber 1a, the plastic film F can be dried almost without being affected by the released gas.

  In addition, as shown in FIG. 2, the surface potential of the plastic film F can be measured by providing a surface potential meter 12 at a position along the path of the plastic film F. As a result, the charge amount of the plastic film F can be accurately grasped, so that an optimal charge removal process can be performed. The position of the surface potential meter 12 is not limited to the position shown in FIG. 2 as long as the surface potential of the plastic film can be measured appropriately.

  In the description of the plastic film heating / conveying device 20 described above, it is assumed that the plastic film F is unwound from the unwinding device 6 and wound by the winding device 8 as shown by the arrows in FIG. Yes. However, it is also possible to rotate the unwinding device 6 and the winding device 8 forward and backward, respectively, so as to perform conveyance in the direction opposite to the arrow direction in addition to the conveyance in the arrow direction shown in FIG. In this way, the unwinding and unwinding are performed in the unwinding chamber 1b, and the unwinding and unwinding are performed in the unwinding chamber 1c. It is preferable to provide the gas blowing means 11 and the surface potential meter 13.

[Example]
The static elimination effect of the static elimination apparatus of this invention was investigated using the heating conveyance apparatus for plastic films shown in FIG. Here, Upilex (registered trademark) -S film (thickness 12.5 μm) manufactured by Ube Industries, Ltd. is used as the plastic film F, and roll-to-roll from the unwinding device 6 toward the winding device 8. It was conveyed by. During this conveyance, the unwinding device 6 and the winding device 8 were provided with a differential speed, and the plastic film F was charged by friction between the plastic film F and the unwinding device 6 and the like generated thereby. The differential speed condition was changed to 0%, 1%, 5% and 10%.

Argon gas was blown out from the gas blowing means 10 toward the plastic film F being conveyed under each of the above differential speed conditions. At the same time, the vacuum evacuation means 3c is activated, and the pressure in the winding chamber 1c is 1.33 × 10 ⁻² Pa to 1.33 × 10 ⁵ Pa (1 × 10 ⁻⁴ Torr to 1 × 10 ³⁾ in absolute pressure. Torr). The surface potential of the plastic film F was measured with a surface potential meter (KSD-0103 manufactured by Kasuga Electric Co., Ltd.) 12 in the winding chamber 1c. The heating device 5 was set so that the thermocouple temperature provided on the surface of the heater was 300 ° C. Moreover, the conveyance speed of the plastic film F was 3 m / min.

  The relationship between the pressure in the winding chamber 1c measured as described above and the surface potential of the plastic film F is shown in FIGS. 3 to 6 for the differential speeds of 0%, 1%, 5%, and 10%, respectively. .

At a differential speed of 10%, the pressure in the winding chamber 1c is 1.29 × 10 ⁻¹ Pa (condition a), 1.99 × 10 ⁻¹ Pa (condition b), 2.93 × 10 ⁻¹ Pa. When (Condition c), 1.33 Pa (Condition d), and 1.33 × 10 ³ Pa (Condition e), the surface potential of the plastic film F was measured, and the results are shown in Table 1 below.

From these results, at a differential speed of 0%, as shown in FIG. 3, there was almost no charging due to friction, and the surface potential was almost zero at any of the above pressures. At a differential speed of 1%, as shown in FIG. 4, charging was recognized on the pressure side lower than 1.33 Pa (1 × 10 ⁻² Torr). Further, as can be seen from FIGS. 5 and 6, it was found that as the differential speed increased from 5% to 10%, the charge amount increased and the absolute value of the surface potential increased.

In addition, when the differential speed was 5% and 10%, the absolute value of the surface potential was higher on the pressure side higher than 1.33 kPa (10 Torr) as well as the lower pressure side lower than 1.33 Pa. . That is, in the range of 1.33 Pa to 1.33 kPa (1 × 10 ⁻² Torr to 10 Torr), the surface potential is almost zero in any of the cases of FIGS. I understood it.

[Comparative example]
As a comparative example, the surface potential of the plastic film F was measured by performing a drying process in the same manner as in the case of the differential speed of 10% in the above example except that no gas was blown out. At that time, the pressure in the winding chamber 1c was set to 0.046 Pa. The obtained results are shown in Table 2 below.

  From this result, it was found that when the gas was not blown out, a good charge removal effect could not be obtained.

It is a graph which shows the relationship between the exhaust time, the surface potential of a plastic film, and a pressure when static elimination is carried out with the static elimination apparatus of this invention. It is the schematic which shows the heating conveyance apparatus for plastic films which concerns on the Example of this invention. It is a graph which shows the relationship between the pressure and surface potential when the plastic film conveyed by 0% of differential speed is neutralized with the static elimination apparatus of this invention. It is a graph which shows the relationship between the pressure and surface potential when the plastic film conveyed by 1% of differential speed is neutralized with the static elimination apparatus of this invention. It is a graph which shows the relationship between the pressure and surface potential when the plastic film conveyed by 5% of differential speed is neutralized with the static elimination apparatus of this invention. It is a graph which shows the relationship between the pressure and surface potential when the plastic film conveyed by differential speed | rate 10% is neutralized with the static elimination apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a Drying chamber 1b Unwinding chamber 1c Winding chamber 3a, 3b, 3c Vacuum exhaust means 5 Heating device 6 Unwinding device 8 Winding device 10, 11 Gas blowing means 12, 13 Surface potential meter 20 Heating and conveying device F for plastic film Plastic film

Claims (4)

  In a vacuum vessel equipped with a vacuum exhaust means, a plastic film static eliminator that neutralizes static electricity charged on the plastic film while conveying the plastic film with a roll-to-roll from the unwinding device to the winding device, There is a blowing means for the gas introduced from the outside of the vacuum vessel in the vicinity of the take-up portion of the winding device, and the gas blowing means blows out the gas toward the plastic film in the vacuumed vacuum vessel. A plastic film static eliminator characterized by: The pressure in the vacuum vessel is set to 1.33 Pa to 1.33 kPa (1 × 10 ⁻² Torr to 10 Torr) in absolute pressure when discharging the gas and discharging electricity. The plastic film static elimination apparatus of description.   In a vacuum vessel equipped with a vacuum evacuation means, the plastic film is transferred from the unwinding device provided in the unwinding chamber to the winding device provided in the take-up chamber by a roll-to-roll, and the heating device is operated. A heating and conveying device for a plastic film that dries in a drying chamber provided with a plastic film static eliminator that neutralizes static electricity charged on the plastic film while conveying the plastic film. A heating / conveying device for a plastic film, comprising gas blowing means for blowing out gas introduced from the outside of the vacuum vessel toward the plastic film in a vacuumed winding chamber. The pressure in the take-up chamber is 1.33 Pa to 1.33 kPa (1 × 10 ⁻² Torr to 10 Torr) in absolute pressure when the gas is blown out to remove static electricity. The heating conveyance apparatus for plastic films as described.

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