JP2016030769A - Method and apparatus for treating surface of film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and an apparatus for treating the surface of a film, in each of which the surface of the film to be treated, which film comprises a fluorine-based resin, is modified chemically to obtain stable adhesive performance.SOLUTION: The method for treating the surface of the film comprises: (a conveyance step of) conveying the film 9 to be treated, which film comprises the fluorine-based resin, in the treatment space 1a, which is formed between a pair of electrodes 21, 11 and has the pressure close to atmospheric pressure; (a gas supply step of) supplying a hydrogen-containing process gas to the treatment space 1a; and (a discharge generation step of) impressing voltage between the pair of electrodes 21, 11 to generate a discharge in the treatment space 1a. The voltage Vp to be impressed between the electrodes is set to be the insulation withstand voltage or higher of the film 9 to be treated.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method and apparatus for surface-treating a film to be treated, and more particularly to a film surface treatment method and apparatus for improving the adhesion by surface-modifying a film to be treated made of a fluororesin.

While the fluorine-based resin is excellent in weather resistance, chemical resistance, and the like, it has poor adhesiveness and is difficult to adhere to an adherend. Therefore, various surface treatment methods have been proposed in order to improve the adhesiveness of the fluororesin.
In Patent Document 1, a fluorine-based resin is subjected to flame treatment or metal sodium treatment.
In Patent Document 2, the surface of the fluorine-based resin is etched with, for example, vacuum plasma in an H ₂ / N ₂ mixed gas atmosphere, and the surface is further irradiated with an excimer laser.
In Patent Document 3, after the surface of a fluorine-based resin is sputter-etched, atmospheric pressure plasma treatment is performed in an atmosphere containing an unsaturated hydrocarbon such as acetylene.

Japanese Patent Publication No. 63-10176 Japanese Patent Laid-Open No. 06-220228 JP 2000-129015 A

In the flame treatment and metal sodium treatment of Patent Document 1, not only environmental problems become large, but also the modified portion becomes weak against ultraviolet rays and heat.
In the vacuum plasma etching and excimer laser processing of Patent Document 2, the equipment becomes large, and the equipment cost increases.
The sputter etching and atmospheric pressure plasma treatment with unsaturated hydrocarbons of Patent Document 3 mainly obtain a physical anchor effect, and the chemical modification effect on the surface of the fluororesin itself is small. Moreover, unsaturated hydrocarbons are easily pulverized and productivity is poor.
In view of the above circumstances, an object of the present invention is to obtain a stable adhesive performance by chemically modifying the surface of a film to be treated made of a fluororesin.

In order to solve the above-mentioned problems, the method of the present invention is a method for surface-treating a film to be treated comprising a fluororesin,
A transporting step of passing the film to be processed through a processing space near the atmospheric pressure formed between a pair of electrodes;
A gas supply step of supplying a process gas containing hydrogen and a discharge product gas to the processing space;
A discharge generation step of generating a discharge in the processing space by applying a voltage equal to or higher than an insulation withstand voltage of the film to be processed between the pair of electrodes;
It is characterized by including.
As a result, the surface of the hardly-adhesive fluororesin can be chemically modified, and stable adhesive performance can be obtained.

The hydrogen content in the process gas is preferably 0.5 vol% to 4 vol%.
As a result, the required processing performance (adhesiveness) can be reliably obtained, and safety can be ensured.

Supplying energy to the electrode from a power source in the discharge generation step, it is preferable that the unit area per 115kJ ^{/ m 2} ~1000kJ ^/ m 2 of the treated film.
Thereby, required processing performance (adhesiveness) can be obtained reliably.

The apparatus of the present invention is an apparatus for surface-treating a film to be processed made of a fluororesin,
A pair of electrodes that define a processing space near atmospheric pressure between each other and generate a discharge in the processing space by applying a voltage;
A transport mechanism for passing the film to be processed through the processing space;
A process gas nozzle for introducing a process gas containing hydrogen and a discharge product gas into the processing space;
The voltage applied between the electrodes is equal to or higher than the dielectric strength voltage of the film to be processed.
As a result, the surface of the hardly-adhesive fluororesin can be chemically modified, and stable adhesive performance can be obtained.

The surface treatment of the present invention is preferably performed near atmospheric pressure. Here, the vicinity of the atmospheric pressure refers to a range of 1.013 × 10 ^{4 to} 50.663 × 10 ⁴ Pa, and considering the ease of pressure adjustment and the simplification of the apparatus configuration, 1.333 × 10 ⁴ to 10.664 × 10 ⁴ Pa is preferable, and 9.331 × 10 ^{4 to} 10.9797 × 10 ⁴ Pa is more preferable.

  The fluorine-based resin refers to a resin containing a fluorine atom, or a resin in which part or all of hydrogen is substituted with fluorine. Specifically, as the fluororesin, polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polyvinyl fluoride (PVF), tetrafluoroethylene / hexafluoropropylene copolymer Examples include coalesce (FEP), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene / ethylene copolymer (ETFE), chlorotrifluoroethylene / ethylene copolymer (ECTFE), and polyvinylidene fluoride (PVDF). .

  ADVANTAGE OF THE INVENTION According to this invention, the surface of a hard-to-adhere fluororesin can be chemically modified and stable adhesive performance can be obtained.

FIG. 1 is an explanatory side view showing a schematic configuration of a film surface treatment apparatus according to an embodiment of the present invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a surface treatment apparatus 1 for a film 9 to be treated. The to-be-processed film 9 consists of fluorine resin. Hereinafter, the film to be treated 9 is appropriately referred to as “fluorine resin film 9”. While the fluorine-based resin is excellent in weather resistance, chemical resistance, and the like, it has low affinity with a general adhesive such as an epoxy resin-based adhesive and is hardly adhesive.

  By surface-modifying the above-mentioned fluorine-based resin film 9 with the surface treatment apparatus 1, the adhesion of the fluorine-based resin film 9 to an adherend (not shown) is enhanced. There is no limitation in particular as a to-be-adhered member. For example, the material of the adherend member may be resin, rubber, or other material. The shape of the adherend member may be a film shape, a plate shape, a cylindrical shape, or other shapes.

  The film surface treatment apparatus 1 includes a roll electrode 11 and a plasma head 20. The roll electrode 11 has a cylindrical shape, and its axis is orthogonal to the paper surface of FIG. At least the outer peripheral portion of the roll electrode 11 is made of metal, and the outer peripheral surface is covered with a solid dielectric layer (not shown). The metal part of the roll electrode 11 is electrically grounded. Thus, the roll electrode 11 constitutes a ground electrode. The film 9 to be processed is wound around the outer circumference of the roll electrode 11 and is in contact with the roll electrode 11. The width direction of the film 9 is directed parallel to the axis of the roll electrode 11 in a direction perpendicular to the paper surface of FIG. Hereinafter, a direction orthogonal to the paper surface of FIG. 1 is referred to as a “processing width direction”.

  A rotation drive unit 12 such as a motor is connected to the roll electrode 11. The roll electrode 11 is rotated, for example, clockwise in FIG. As the roll electrode 11 rotates, the film to be processed 9 is conveyed in the direction indicated by the arrow a in FIG. The roll electrode 11 and the rotation drive unit 12 constitute a transport mechanism 13 for the film 9 to be processed.

  Furthermore, the roll electrode 11 is provided with temperature adjusting means 16. The temperature adjustment means 16 includes a temperature adjustment medium flow path 16 a in the roll electrode 11. A temperature control medium such as water is adjusted to a predetermined temperature and then passed through the temperature control medium flow path 16a. Thereby, the film 9 to be processed is temperature-controlled (cooled) via the roll electrode 11.

  A plasma head 20 is provided on one side of the roll electrode 11 (right side in FIG. 1). The plasma head 20 includes a flat plate electrode 21 and a dielectric member 22. The plate electrode 21 is made of metal and has a long plate shape extending in the processing width direction orthogonal to the paper surface of FIG. The flat plate electrode 21 is connected to the high frequency power source 2. The high frequency power source 2 converts direct current power into high frequency alternating current and supplies it to the plate electrode 21. Thus, the plate electrode 21 is a voltage application electrode.

  The plate electrode 21 is provided with temperature adjusting means 26. The temperature adjustment means 26 includes a temperature adjustment medium channel 26 a in the flat plate electrode 21. A temperature control medium such as water is adjusted to a predetermined temperature and then passed through the temperature control medium flow path 26a. Thereby, the temperature of the plate electrode 21 is adjusted.

  The roll electrode 11 and the plate electrode 21 are opposed to each other in a facing direction (left-right direction in FIG. 1) orthogonal to the processing width direction, thereby forming a pair of electrodes. A surface of the flat plate electrode 21 facing the roll electrode 11 constitutes a discharge surface 21a. The discharge surface 21a is a plane in which the longitudinal direction is directed in the processing width direction (the direction orthogonal to the paper surface in FIG. 1), and the short side direction is directed in the longitudinal direction (up and down in FIG. 1) orthogonal to the processing width direction and the opposing direction. ing.

  A dielectric member 22 is provided on the discharge surface 21 a of the plate electrode 21. The dielectric member 22 is made of, for example, ceramic (dielectric material) and has a flat plate shape having a larger area than the discharge surface 21a. The entire discharge surface 21 a is covered with the dielectric member 22.

  A processing space 1a is defined in the narrowest portion between the dielectric member 22 and the roll electrode 11 and its peripheral portion. The processing space 1a extends in the processing width direction (the direction perpendicular to the plane of FIG. 1), and both ends in the vertical direction (up and down in FIG. 1) communicate with the external atmosphere. The pressure in the processing space 1a is almost atmospheric pressure. A projected area (discharge area) when the processing space 1a is viewed from the opposing direction of the electrodes 21 and 11 (left and right sides in FIG. 1) is substantially equal to the area of the discharge surface 21a. The thickness along the facing direction of the narrowest part of the processing space 1a is preferably about 0.6 mm to 2.0 mm, more preferably about 1 mm. If it is smaller than 0.6 mm, it is difficult to pass the film 9 to be processed having the maximum thickness (generally about 0.5 mm). If it is larger than 2.0 mm, the discharge is not stable.

An electric field is applied between the electrodes 21 and 11 by supplying power from the high-frequency power source 2. As a result, a discharge is generated in the processing space 1a, and the processing space 1a becomes a discharge space. As will be described in detail later, the applied voltage Vp between the electrodes 21 and 11 is set to a relatively high voltage corresponding to the dielectric strength voltage of the film 9 to be processed.
A portion of the film 9 to be processed that is wound around the roll electrode 11 is disposed in the processing space 1a.

  A nozzle unit 30 is attached to one side of the plasma head 20 in the vertical direction (upper side in FIG. 1). The nozzle unit 30 extends in the processing width direction orthogonal to the paper surface of FIG. The nozzle unit 30 is provided with a process gas nozzle 31 and a curtain gas nozzle 34. The process gas nozzle 31 is opened obliquely toward the processing space 1a. A process gas supply source 3 is connected to the nozzle 31. The process gas supply source 3 supplies process gas to the nozzle 31. This process gas is blown out from the nozzle 31 and flows toward the processing space 1a. The blow-out flow of the process gas is made uniform in the process width direction.

The process gas contains hydrogen and a discharge product gas (or dilution gas). The discharge generated gas is a gas for generating a stable plasma discharge in the processing space 1a, and an inert gas is preferably used. Examples of the inert gas include nitrogen (N ₂ ) and rare gases such as argon (Ar) and helium (He). Here, nitrogen (N ₂ ) is used as the discharge product gas from the viewpoint of cost and the like. The volume content of hydrogen in the process gas is preferably about H ₂ x100 / (N ₂ + H ₂ ) = 0.5 vol% to 4 vol%. If the hydrogen content is too low, it becomes difficult to obtain a desired effect. If the hydrogen content is too high, safety issues arise. The upper limit (4 vol%) of the hydrogen content range corresponds to the explosion limit concentration of hydrogen in the atmosphere.

A curtain gas nozzle 34 is arranged outside the process gas nozzle 31 in the nozzle unit 30 (on the side opposite to the plate electrode 21). The curtain gas nozzle 34 is opened toward the roll electrode 11. The curtain gas supply source 4 is connected to the nozzle 34. The curtain gas supply source 4 supplies curtain gas to the nozzle 34. For example, nitrogen (N ₂ ) is used as the curtain gas. When this curtain gas is blown out from the nozzle 34, a gas curtain is formed between the nozzle 34 and the roll electrode 11.

  A shielding wall 25 is provided on the side of the plasma head 20 opposite to the nozzle unit 30 (lower side in FIG. 1). The shielding wall 25 protrudes from the dielectric member 22 to the roll electrode 11 side.

A method for surface-treating the film 9 made of a fluororesin by the film surface treatment apparatus 1 will be described.
<Conveying process>
The film 9 to be processed is wound around the roll electrode 11. Then, the roll electrode 11 is rotated clockwise in FIG. 1, and the film 9 to be processed is conveyed at a predetermined speed in the direction of arrow a. This processed film 9 is passed through the processing space 1a in the vertical direction.

<Gas supply process>
In parallel with the conveyance of the film 9 to be processed, the process gas (N ₂ + H ₂ ) from the process gas supply source 3 is blown out from the process gas nozzle 31 and supplied to the processing space 1a.
<Gas curtain formation process>
Further, curtain gas (N ₂ ) from the curtain gas supply source 4 is blown out from the curtain gas nozzle 34 to form a gas curtain on the upstream side in the transport direction near the processing space 1a.

<Discharge generation process>
In parallel, a high frequency voltage is applied between the high frequency power source 2 and the electrodes 21 and 11. Thereby, a discharge is generated in the processing space 1a, and the process gas is turned into plasma. This plasma is irradiated to the film 9 to be processed in the processing space 1a.

<Applied voltage setting>
Here, the magnitude of the voltage applied between the electrodes 21 and 11 is set in accordance with the insulation withstand voltage V _9S of the film 9 to be processed. Specifically, the voltage applied between the electrodes 21 and 11 (preferably the peak voltage Vp) is set to an insulation withstand voltage V _9S or higher of the film 9 to be processed (Vp ≧ V _9S ). When the applied voltage is too low, the degree of surface modification of the film 9 to be processed becomes insufficient. Further, the upper limit of the applied voltage is appropriately set according to the capability of the film surface treatment apparatus 1 to such an extent that the film 9 to be treated is not damaged.

  The dielectric strength voltage of the film 9 to be processed depends on the material and thickness of the film 9 to be processed. For example, when the film 9 is made of polytetrafluoroethylene (PTFE), the dielectric strength voltage per unit thickness is about 19 kV / mm. When the to-be-processed film 9 consists of a tetrafluoroethylene perfluoroalkyl vinyl ether copolymer (PFA), the insulation withstand voltage per unit thickness is about 20 kV / mm. When the film 9 to be treated is made of a tetrafluoroethylene / hexafluoropropylene copolymer (FEP), the dielectric strength voltage per unit thickness is about 22 kV / mm. When the to-be-processed film 9 consists of polychlorotrifluoroethylene (PCTFE), the dielectric strength voltage per unit thickness is about 22 kV / mm. When the film 9 to be treated is made of tetrafluoroethylene / ethylene copolymer (ETFE), the dielectric strength voltage per unit thickness is about 16 kV / mm. When the film 9 to be treated is made of chlorotrifluoroethylene / ethylene copolymer (ECTFE), the dielectric strength voltage per unit thickness is about 20 kV / mm. When the to-be-processed film 9 consists of polyvinylidene fluoride (PVDF), the dielectric strength voltage per unit thickness is about 11 kV / mm.

<Supply energy setting>
More preferably, set to be the supply energy from the power source 2 to 115kJ ^{/ m 2} ~1000kJ ^/ m 2 approximately per unit area of the processed film 9. If the supplied energy is below the above numerical range, it may be difficult to obtain desired processing performance. When the supplied energy exceeds the above numerical range, the processing speed is too slow to ensure productivity, the required power exceeds the power supply capacity, or the film 9 to be processed is damaged. There is a fear. The supplied energy is defined by the product of the supplied power and the processing time at each location of the film 9 to be processed. A value obtained by dividing this supply energy by the discharge area (equivalent to the area of the discharge surface 21a) is the supply energy per unit area of the film 9 to be processed. The supply power can be defined by the DC supply power before high-frequency conversion in the power supply 2. Moreover, the processing time of each part of the to-be-processed film 9 respond | corresponds with the time when each said part passes the process space 1a, the conveyance speed of the to-be-processed film 9, and the vertical direction (FIG. 1 in the vertical direction).

<Temperature control process>
At the same time, temperature-controlled water is caused to flow through the temperature-control medium flow path 16 a in the roll electrode 11. The temperature of the temperature-controlled water is preferably about room temperature (for example, 23 ° C.) to about 40 ° C., more preferably about 30 ° C. Thereby, the film 9 to be processed can be temperature-controlled (cooled) via the roll electrode 11. Therefore, even if the film 9 to be processed is exposed to high voltage and high energy in the processing space 1a and temporarily becomes high temperature (for example, 100 ° C. or higher), it can be immediately cooled. Therefore, it can suppress or prevent that the to-be-processed film 9 brings about a thermal deformation.
Moreover, the temperature of the flat plate electrode 21 can be controlled by flowing the temperature-controlled water through the temperature adjusting medium channel 26 a in the flat plate electrode 21, and thermal deformation of the flat plate electrode 21 can be suppressed or prevented.

According to this surface treatment method, the surface of the fluororesin film 9 can be chemically modified. In particular, by using a hydrogen-containing gas as the process gas and setting the applied voltage Vp to a high voltage equal to or higher than the insulation withstand voltage _V9S of the film 9 to be processed, the chemical modification can be surely expressed.
Specifically, it is considered that the C—F bond of the surface molecule of the fluorine-based resin film 9 is cut to form a C—H bond, a C—OH bond, or the like. These C—H bonds, C—OH bonds, and the like have high affinity with general adhesives such as epoxy resin adhesives. Thereby, the adhesiveness of the fluorine resin film 9 can be enhanced. The oxygen atoms in the C—OH bond are derived from oxygen in the ambient atmosphere (air) of the film surface treatment apparatus 1.
Since the film surface treatment apparatus 1 performs treatment under atmospheric pressure, a large-scale vacuum facility or the like is unnecessary, and facility costs can be suppressed.
Further, since the process gas does not contain a polymerizable component such as an unsaturated hydrocarbon, it can be prevented from being pulverized. Therefore, the yield can be improved and the production efficiency can be increased.

<Adhesion process>
An adhesive such as an epoxy resin adhesive is applied to the fluorine resin film 9 subjected to the above surface treatment. As described above, the surface of the fluororesin film 9 is easily attached with an adhesive because the affinity with the adhesive is enhanced by chemical modification. Thereby, the fluororesin film 9 can be reliably bonded to the adherend.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, the pair of electrode structures is not limited to the pair of the roll electrode 11 and the flat plate electrode 21 but may be formed of a pair of roll electrodes or a pair of flat plate electrodes.
The supply energy from the power source 2 may be set in consideration of transmission loss, may be less than the above numerical range, or may be above the above numerical range.

Examples will be described. The present invention is not limited to the following examples.
In Example 1, the surface treatment of the film to be treated 9 made of a fluorine-based resin was performed using the same apparatus as the film surface treatment apparatus 1 shown in FIG. That is, while the film to be processed 9 is wound around the roll electrode 11 and conveyed (conveying process), process gas is supplied from the process gas nozzle 31 to the processing space 1a (gas supply process), and an electric field is applied between the electrodes 21 and 11. Thus, an atmospheric pressure plasma discharge was generated (discharge generation process).

<Film to be processed>
The material of the film 9 to be treated was polytetrafluoroethylene (PTFE).
The thickness t _{9 of the} film 9 to be processed was t ₉ = 250 μm.
As described above, since the dielectric strength voltage per unit thickness of polytetrafluoroethylene (PTFE) is 19 kV / mm, the dielectric strength voltage V _9S of the film to be processed 9 of Example 1 is V _9S = 4. It was 75 kV.

<Device configuration>
The length of the electrodes 21, 11 and the processing space 1a in the processing width direction (the direction perpendicular to the plane of FIG. 1) was 640 mm.
The dimension in the longitudinal direction (vertical direction in FIG. 1) of the flat electrode 21 and the processing space 1a was 30 mm.
Therefore, the discharge area of the processing space 1a (the area of the discharge surface 21a) was 19200 mm ² (= 0.0192 m ² ).
The thickness of the narrowest part of the processing space 1a was 1 mm.

<Processing speed>
The processing speed (conveying speed of the film 9 to be processed) was 0.3 m / min. Therefore, the processing time (time for passing through the processing space 1a) of each part of the processed film 9 was 6 seconds.
<Set temperature>
The set temperature of the roll electrode 11 and thus the film 9 to be treated was 30 ° C.
The set temperature of the plate electrode 21 was 30 ° C.

<Process gas, etc.>
A mixed gas of N ₂ and H ₂ was used as the process gas.
The overall flow rate of process gas was 50 slm.
Among them, the flow rate of N ₂ was 48 slm, and the flow rate of H ₂ was ₂ slm.
Thus, _{H 2} content in the process gas _{was H 2 x100 / (N 2 +} H 2) = 4vol%.
The flow rate of curtain gas (N ₂ ) was 25 slm.

<Supply energy>
In the high frequency power source 2, commercial AC power was converted into DC, and this DC power was converted into high frequency and supplied to the plate electrode 21.
The supplied DC voltage was 600V.
The supplied direct current was 2A.
Therefore, the supplied power was 1200W.
The supply energy per unit area of the film 9 to be processed based on this supply power was (supply power) × (treatment time) / (discharge area) = 375 kJ / m ² .

<Applied voltage>
The applied voltage (peak voltage Vp) between the electrodes 21 and 11 was Vp = 7.5 kV. That is, it was set higher than the dielectric strength voltage (V _9S = 4.75 kV) of the film 9 to be processed (Vp ≧ V _9S ).
The peak-to-peak voltage Vpp was Vpp = 15 kV.
The frequency of the applied voltage was 40 kHz.

<Adhesion process>
A sample piece was cut out from the film 9 to be surface-treated as described above, and an adhesive was applied thereto. As the adhesive, a room temperature curing epoxy resin was used.
Another sample piece was stacked on the sample piece to which the adhesive was applied and pressed. The applied pressure was 10 MPa and the pressing time was 3 hours.

<Evaluation>
A peeling test based on 1999 JIS K6854 was performed on the sample thus produced, and the peeling force (adhesive strength) at the time of peeling of both sample pieces was measured.
The measurement result was 4.4 N / inch per inch of sample width, and a sufficiently large adhesive strength could be obtained.

In Example 2, the composition of the process gas was as follows.
N ₂ 49slm
H _{2 1} slm
Total flow rate 50 slm
Therefore, the hydrogen content in the process gas was 2 vol%.
Other processing conditions and processing procedures were the same as in Example 1. The sample preparation and evaluation procedures after the treatment were also the same as in Example 1.
As a result, the adhesive strength was 3.7 N / inch.

In Example 3, the composition of the process gas was as follows.
N ₂ 49.5 slm
H ₂ 0.5 slm
Total flow rate 50 slm
Therefore, the hydrogen content in the process gas was 1 vol%.
Other processing conditions and processing procedures were the same as in Example 1. The sample preparation and evaluation procedures after the treatment were also the same as in Example 1.
As a result, the adhesive strength was 3.1 N / inch.

In Example 4, the composition of the process gas was as follows.
N ₂ 49.75 slm
H ₂ 0.25 slm
Total flow rate 50 slm
Therefore, the hydrogen content in the process gas was 0.5 vol%.
Other processing conditions and processing procedures were the same as in Example 1. The sample preparation and evaluation procedures after the treatment were also the same as in Example 1.
As a result, the adhesive strength was 2.1 N / inch.
From the above examples, it was confirmed that if the hydrogen content in the process gas is 0.5 vol% or more, the required adhesion performance (processing performance) can be obtained. The higher the hydrogen content in the process gas was within the explosion limit, the higher the adhesion performance.

Table 1 summarizes the processing conditions and evaluation results of Examples 1 to 4.

In Example 5, the conveyance speed (processing speed) of the to-be-processed film 9 was 0.5 m / min. Therefore, the processing time of each part of the to-be-processed film 9 was 3.6 seconds. The supply energy from the power source 2 was (supply power) × (processing time) / (discharge area) = 225 kJ / m ² per unit area of the film 9 to be processed.
Other processing conditions and processing procedures were the same as in Example 1. The sample preparation and evaluation procedures after the treatment were also the same as in Example 1.
As a result, the adhesive strength was 3.4 N / inch.

In Example 6, the conveyance speed (processing speed) of the to-be-processed film 9 was 1 m / min. Therefore, the processing time of each part of the to-be-processed film 9 was 1.8 second. Further, the supply energy from the power source 2 was (supply power) × (processing time) / (discharge area) = 112.5 kJ / m ² per unit area of the film 9 to be processed.
Other processing conditions and processing procedures were the same as in Example 1. The sample preparation and evaluation procedures after the treatment were also the same as in Example 1.
As a result, the adhesive strength was 2.3 N / inch.
From Examples 1, 5, and 6, it was confirmed that the processing performance was also affected by the supplied energy. If the supply energy from the power source 2 is 115 kJ / m ² or more per unit area of the film to be processed 9 in consideration of measurement variations, sufficient processing performance (adhesiveness) can be secured.

Table 2 summarizes the processing conditions and evaluation results of Examples 5 and 6.

[Comparative Example 1]
As Comparative Example 1, the withstand voltage of the film to be processed 9 was increased by increasing the thickness of the film 9 to be processed made of polytetrafluoroethylene (PTFE). Specifically, the thickness t _{9 of the} film 9 to be processed was set to t ₉ = 500 μm, which is twice that of Example 1. Therefore, the withstand voltage V _9S of the film to be processed ₉ was V _9S = 9.5 kV. For this reason, the applied voltage (Vp = 7.5 kV) between the electrodes 21 and 11 was lower than the insulation withstand voltage V _{9S of the} film 9 to be processed (Vp <V _9S ).
Furthermore, the supply DC power of the power source 2 was 600 V, the supply DC current was 1.6 A, and the supply DC power was 960 W. Therefore, the supply energy per unit area of the film 9 to be processed based on the supplied DC power was about (supply power) × (treatment time) / (discharge area) = 300 J / m ² .
Other processing conditions and processing procedures were the same as in Example 1. The sample preparation and evaluation procedures after the treatment were also the same as in Example 1.
As a result, the adhesive strength was 0.8 N / inch.

[Comparative Example 2]
As Comparative Example 2, the thickness t _{9 of the} film 9 made of polytetrafluoroethylene (PTFE) was set to t ₉ = 400 μm. Therefore, the withstand voltage V _9S of the film 9 to be processed was V _9S = 7.6 kV.
The applied voltage (peak voltage Vp) between the electrodes 21 and 11 was set to Vp = 6.5 kV.
Therefore, the applied voltage Vp was lower than the insulation withstand voltage V _{9S of the} film 9 to be processed (Vp <V _9S ).
Furthermore, the supply DC power of the power source 2 was set to 600 V, the supply DC current was set to 1.67 A, and the supply DC power was set to 1000 W. Therefore, the supply energy per unit area of the film 9 to be processed based on the supplied DC power was (supply power) × (processing time) / (discharge area) = 312.5 J / m ² .
Other processing conditions and processing procedures were the same as in Example 1. The sample preparation and evaluation procedures after the treatment were also the same as in Example 1.
As a result, the adhesive strength was 0.8 N / inch.
From Example 1 and Comparative Examples 1 and 2 were found to affect the treated film 9 of the insulating withstand voltage V _9S relationship process between the applied voltage Vp between the electrodes 21, 11 performance (bonding strength). That is, if the applied voltage Vp is a high voltage equal to or higher than the withstand voltage V _9S (Vp ≧ V _9S ), desired processing performance can be obtained, while the applied voltage Vp is lower than the withstand voltage V _9S of the film 9 to be processed. The degree (Vp <V _9S ) makes it difficult to obtain desired processing performance.

[Comparative Example 3]
In Comparative Example 3, the process gas was 100% N _{2 and} 50 slm. That is, the H ₂ content in the process gas was set to 0 vol%.
Other processing conditions and processing procedures were the same as in Example 1. The sample preparation and evaluation procedures after the treatment were also the same as in Example 1.
As a result, the adhesive strength was 0.7 N / inch.
According to Example 1 and Comparative Example 3, it was confirmed that it was important to include hydrogen in the process gas in order to obtain a desired processing performance.

Table 3 summarizes the processing conditions and evaluation results of Comparative Examples 1 to 3.

  From the results of the above examples and comparative examples, by using a process gas containing hydrogen and applying a voltage Vp that is equal to or higher than the dielectric strength voltage of the film to be processed 9 between the electrodes 21 and 11, It was confirmed that the adhesiveness can be improved.

  The present invention can be applied to improve the adhesiveness of a film made of a fluororesin such as polytetrafluoroethylene (PTFE) and adhere it to an adherend.

DESCRIPTION OF SYMBOLS 1 Film surface treatment apparatus 1a Processing space 2 Power supply 3 Process gas supply source 9 Fluorine resin film (film to be processed)
11 Roll electrode (ground electrode)
13 Transport mechanism 21 Flat plate electrode (voltage application electrode)
21a Discharge surface 31 Process gas nozzle

Claims (4)

A method for surface-treating a film to be treated made of a fluororesin,
A transporting step of passing the film to be processed through a processing space near the atmospheric pressure formed between a pair of electrodes;
A gas supply step of supplying a process gas containing hydrogen and a discharge product gas to the processing space;
A discharge generation step of generating a discharge in the processing space by applying a voltage equal to or higher than an insulation withstand voltage of the film to be processed between the pair of electrodes;
A film surface treatment method comprising:   The film surface treatment method according to claim 1, wherein a hydrogen content in the process gas is 0.5 vol% to 4 vol%. Said discharge generation and supply energy from the power source in step to the electrode, the film surface treatment according to claim 1 or 2, characterized in that the 115kJ ^/ m ² ~1000kJ / m 2 per unit area of the processed film Method. An apparatus for surface-treating a film to be processed made of a fluorine-based resin,
A pair of electrodes that define a processing space near atmospheric pressure between each other and generate a discharge in the processing space by applying a voltage;
A transport mechanism for passing the film to be processed through the processing space;
A process gas nozzle for introducing a process gas containing hydrogen and a discharge product gas into the processing space;
And the applied voltage between the electrodes is equal to or higher than the dielectric strength voltage of the film to be processed.

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