JP6510774B2 - Film surface treatment method and apparatus - Google Patents

Description

  The present invention relates to a method and apparatus for surface treatment of a film to be treated, and more particularly to a film surface treatment method and apparatus for surface modification of a film to be treated made of a fluorine resin to improve adhesion.

The fluorine-based resin is excellent in weather resistance, chemical resistance and the like, but the adhesion of the adhesive is poor, and it is difficult to adhere to the member to be adhered. Therefore, various surface treatment methods have been proposed to improve the adhesiveness of the fluorine-based resin.
In Patent Document 1, a fluorine-based resin is subjected to flame treatment or metal sodium treatment.
In Patent Document 2, for example, the surface of a fluorine-based resin is etched by 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 sputter-etching the surface of a fluorine-based resin, atmospheric pressure plasma treatment is performed in an atmosphere containing an unsaturated hydrocarbon such as acetylene.

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

In the flame treatment and metal sodium treatment of Patent Document 1, not only environmental problems become serious, but also the reformed portion becomes weak to ultraviolet light and heat.
In the vacuum plasma etching and excimer laser processing of Patent Document 2, the equipment cost is increased because the equipment becomes large.
The sputter etching and the atmospheric pressure plasma treatment with unsaturated hydrocarbon of Patent Document 3 mainly obtain a physical anchor effect, and the chemical modification effect of the surface of the fluorine resin itself is small. In addition, unsaturated hydrocarbons are easily pulverized and the productivity is poor.
An object of this invention is to chemically modify the surface of the to-be-processed film which consists of fluorine-type resin, and to acquire the stable adhesion performance in view of the said situation.

In order to solve the above problems, the method of the present invention is a method of surface treating a film to be treated comprising a fluorine-based resin,
Conveying 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 generating step of generating a discharge in the processing space by applying a voltage higher than the insulation withstand voltage of the film to be processed between the pair of electrodes;
It is characterized by including.
By this, the surface of the poorly adhesive fluorocarbon resin 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.
By this, the required processing performance (adhesiveness) can be reliably obtained.

The apparatus according to the present invention is an apparatus for surface treating a film to be treated made of a fluorine-based resin,
A pair of electrodes defining a processing space near atmospheric pressure between each other and generating 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 insulation withstand voltage of the film to be treated.
By this, the surface of the poorly adhesive fluorocarbon resin 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 means a range of 1.013 × 10 ^{4 to} 50.663 × 10 ⁴ Pa, and in consideration of facilitation of pressure adjustment and simplification of the device configuration, 1.333 × 10 ⁴ to 10.664 × ¹⁰ 4 Pa, and more preferably from ^{9.331 × 10 4 ~10.397 × 10 4} Pa.

  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 a fluorine-based resin, polytetrafluoroethylene (PTFE), tetrafluoroethylene / perfluoroalkylvinylether copolymer (PFA), polyvinyl fluoride (PVF), tetrafluoroethylene / hexafluoropropylene copolymer, etc. Combined (FEP), polychlorotrifluoroethylene (PCTFE), tetrafluoroethylene / ethylene copolymer (ETFE), chlorotrifluoroethylene / ethylene copolymer (ECTFE), polyvinylidene fluoride (PVDF), etc. may be mentioned. .

  According to the present invention, the surface of the poorly adhesive fluorocarbon resin 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 to-be-processed film 9 is suitably called "the fluorine resin film 9". A fluorine-based resin is excellent in weather resistance, chemical resistance and the like, but has low affinity with common adhesives such as epoxy resin-based adhesives and is difficult to bond.

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

  The film surface processing 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 portion of the roll electrode 11 is electrically grounded. The roll electrode 11 thereby constitutes a ground electrode. The film 9 to be treated is wound around about a half circumference of the outer periphery of the roll electrode 11 and is in contact with the roll electrode 11. The width direction of the film 9 to be processed is oriented parallel to the axis of the roll electrode 11 in the direction perpendicular to the paper surface of FIG. Hereinafter, the direction orthogonal to the paper surface of FIG. 1 is referred to as “processing width direction”.

  A rotational 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. 1 by the rotation drive unit 12. With the rotation of the roll electrode 11, the film 9 to be treated is conveyed in the direction shown 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.

  Further, the roll electrode 11 is provided with temperature control means 16. The temperature control means 16 includes a temperature control medium channel 16 a in the roll electrode 11. A temperature control medium such as water is passed through the temperature control medium channel 16a after being adjusted to a predetermined temperature. Thus, the film 9 to be treated is temperature-controlled (cooled) through the roll electrode 11.

  A plasma head 20 is provided on one side (right in FIG. 1) of the roll electrode 11. The plasma head 20 includes a flat plate electrode 21 and a dielectric member 22. The flat 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 supply 2. The high frequency power supply 2 converts direct current power into high frequency alternating current and supplies it to the flat plate electrode 21. Thus, the flat plate electrode 21 is a voltage application electrode.

  A temperature control means 26 is provided on the flat plate electrode 21. The temperature control means 26 includes a temperature control medium channel 26 a in the flat plate electrode 21. A temperature control medium such as water is passed through the temperature control medium channel 26a after being adjusted to a predetermined temperature. The temperature of the flat plate electrode 21 is adjusted by this.

  The roll electrode 11 and the flat plate electrode 21 constitute a pair of electrodes by facing each other in the opposing direction (left and right direction in FIG. 1) orthogonal to the processing width direction. The surface of the flat plate electrode 21 facing the roll electrode 11 constitutes a discharge surface 21 a. The discharge surface 21a is a plane in which the longitudinal direction is directed to the treatment width direction (the direction orthogonal to the sheet of FIG. 1) and the short direction is directed to the treatment width direction and the vertical direction (up and down in FIG. ing.

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

  A processing space 1a is defined at the narrowest portion between the dielectric member 22 and the roll electrode 11 and the periphery thereof. The processing space 1a extends in the processing width direction (the direction orthogonal to the paper surface of FIG. 1), and both ends in the vertical direction (upper and lower in FIG. 1) communicate with the external atmosphere. The pressure in the processing space 1a is approximately atmospheric pressure. The projected area (discharge area) when the processing space 1a is viewed from the opposing direction (left and right sides in FIG. 1) of the electrodes 21 and 11 is substantially equal to the area of the discharge surface 21a. The thickness along the opposite direction of the narrowest portion of the processing space 1a is preferably about 0.6 mm to 2.0 mm, and more preferably about 1 mm. If it is smaller than 0.6 mm, it is difficult to pass the to-be-processed film 9 of 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 the power supply 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 described later in detail, the applied voltage Vp between the electrodes 21 and 11 is set to a relatively high voltage according to the insulation withstand voltage of the film 9 to be processed.
The part wound around the roll electrode 11 in the to-be-processed film 9 is arrange | positioned in the processing space 1a.

  A nozzle unit 30 is attached to one side (upper side in FIG. 1) of the plasma head 20 in the longitudinal direction. The nozzle unit 30 extends as long as the plasma head 20 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 obliquely opened toward the processing space 1a. The process gas supply source 3 is connected to the nozzle 31. The process gas supply source 3 supplies a process gas to the nozzle 31. The process gas is blown out of the nozzle 31 and flows toward the processing space 1a. The flow of the process gas is uniformed in the process width direction.

The process gas contains hydrogen and a discharge product gas (or a dilution gas). The discharge generated gas is a gas for generating a stable plasma discharge in the processing space 1a, and preferably an inert gas is used. As the inert gas, in addition to nitrogen (N ₂ ), rare gases such as argon (Ar) and helium (He) can be mentioned. Here, nitrogen (N ₂ ) is used as the discharge generated gas from the viewpoint of cost and the like. Volume content of hydrogen in the process gas _{is, H 2 x100 / (N 2} + H 2) = about 0.5vol% ~4vol% is preferred. If the hydrogen content is too low, it will be difficult to obtain the 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 explosive limit concentration of hydrogen in the atmosphere.

A curtain gas nozzle 34 is disposed outside the process gas nozzle 31 in the nozzle unit 30 (opposite to the flat 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. The curtain gas is blown out from the nozzle 34 to form a gas curtain 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 to the roll electrode 11 side more than the dielectric member 22.

The method to surface-treat the to-be-processed film 9 which consists of fluorine resin by said film surface treatment apparatus 1 is demonstrated.
<Transporting process>
The film 9 to be treated is wound around the roll electrode 11. Then, the roll electrode 11 is rotated clockwise in FIG. 1 to convey the film 9 to be processed in the direction of arrow a at a predetermined speed. The film 9 to be processed is passed in the longitudinal direction in the processing space 1a.

<Gas supply process>
At the same time as the transport 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 1 a.
<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 1 a.

<Discharge generation process>
Further in parallel, a high frequency voltage is applied between the electrodes 21 and 11 from the high frequency power supply 2. As a result, a discharge is generated in the processing space 1a to plasmify the process gas. This plasma is irradiated to the to-be-processed film 9 in the processing space 1a.

<Application 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 _{9 S} of the film 9 to be processed. Specifically, the applied voltage (preferably the peak voltage Vp) between the electrodes 21 and 11 is set to the insulation withstand voltage V _{9S of the} film 9 to be processed or more (Vp V V _9S ). When the applied voltage is too low, the degree of surface modification of the film 9 to be treated becomes insufficient. Moreover, the upper limit of the applied voltage is suitably set according to the capability of the film surface processing apparatus 1 to such an extent that the to-be-processed film 9 is not damaged.

  The insulation withstand voltage of the film 9 to be treated depends on the material and thickness of the film 9 to be treated. For example, when the to-be-processed film 9 consists of polytetrafluoroethylene (PTFE), the insulation withstand voltage per unit thickness is about 19 kV / mm. When the to-be-processed film 9 consists of a tetrafluoroethylene perfluoro alkyl vinyl ether copolymer (PFA), the insulation withstand voltage per unit thickness is about 20 kV / mm. When the to-be-processed film 9 consists of a tetrafluoroethylene hexafluoropropylene copolymer (FEP), the insulation withstand voltage per unit thickness is about 22 kV / mm. When the to-be-processed film 9 consists of polychloro trifluoro ethylene (PCTFE), the insulation withstand voltage per unit thickness is about 22 kV / mm. When the to-be-processed film 9 consists of a tetrafluoroethylene ethylene copolymer (ETFE), the insulation withstand voltage per unit thickness is about 16 kV / mm. When the to-be-processed film 9 consists of a chloro trifluoro ethylene ethylene copolymer (ECTFE), the insulation withstand voltage per unit thickness is about 20 kV / mm. When the to-be-processed film 9 consists of polyvinylidene fluoride (PVDF), the insulation withstand 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 less than the above numerical range, it may be difficult to obtain the desired processing performance. If 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 is damaged. There is a fear. The supplied energy is defined by the product of the supplied power and the processing time of each portion of the film 9 to be processed. The value obtained by dividing the supplied energy by the discharge area (equivalent to the area of the discharge surface 21 a) is the supplied energy per unit area of the film 9 to be treated. The supplied power can be defined by the DC supplied power before high frequency conversion in the power supply 2. The processing time of each part of the film 9 corresponds to the time when each part passes through the processing space 1a, the transport speed of the film 9 to be processed, and the longitudinal direction of the processing space 1a and thus the discharge surface 21a (see FIG. It can be adjusted by the dimension of 1).

<Temperature control process>
Further, temperature control water is allowed to flow through the temperature control medium channel 16 a in the roll electrode 11. The temperature of the temperature-controlled water is preferably about normal temperature (for example, 23 ° C.) to about 40 ° C., and more preferably about 30 ° C. Thus, the film 9 to be processed can be temperature-controlled (cooled) through the roll electrode 11. Therefore, even if the film 9 to be treated is exposed to high voltage and high energy in the treatment space 1a and temporarily becomes high temperature (for example, 100 ° C. or more), it can be cooled immediately. Therefore, it can suppress or prevent that the to-be-processed film 9 causes a thermal deformation.
Further, by flowing temperature-controlled water through the temperature control medium channel 26 a in the flat plate electrode 21, the temperature of the flat plate electrode 21 can be controlled, and thermal deformation of the flat plate electrode 21 can be suppressed or prevented.

According to this surface treatment method, the surface of the fluorine-based resin 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 V _{9 S} of the film 9 to be processed, chemical modification can be reliably developed.
Specifically, it is considered that the C—F bond of the surface molecule of the fluorine-based resin film 9 is broken to form a C—H bond, a C—OH bond, and the like. These C—H bonds, C—OH bonds, and the like have high affinity with common adhesives such as epoxy resin adhesives. By this, the adhesiveness of the fluorine resin film 9 can be improved. In addition, the oxygen atom in a C-OH bond originates in the oxygen in the ambient atmosphere (air) of the film surface processing apparatus 1. FIG.
Since the film surface processing apparatus 1 performs processing under atmospheric pressure, large-scale vacuum equipment and the like are unnecessary, and equipment cost can be suppressed.
In addition, since the process gas does not contain a polymerizable component such as unsaturated hydrocarbon, powderization can be prevented. Therefore, the yield can be improved and the production efficiency can be improved.

Bonding process
An adhesive such as an epoxy resin adhesive is applied to the fluorine-based resin film 9 subjected to the above surface treatment. As described above, since the surface of the fluorine-based resin film 9 is enhanced in affinity with the adhesive by the chemical modification, the adhesive is easily attached. By this, the fluorine-based resin film 9 can be reliably adhered to the adherend member.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the scope of the 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 and may be configured by a pair of roll electrodes or may be configured by a pair of flat plate electrodes.
The energy supplied 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, using the apparatus substantially the same as the film surface treatment apparatus 1 shown in FIG. That is, while the film 9 to be treated is wound around the roll electrode 11 and conveyed (conveying process), the 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 Then, an atmospheric pressure plasma discharge was generated (discharge generation step).

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

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

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

<Process gas etc.>
A mixed gas of N ₂ and H ₂ was used as a process gas.
The total flow rate of the 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 the curtain gas _{(N 2)} was 25 slm.

<Supply energy>
Commercial AC power is DC converted in the high frequency power supply 2, and this DC power is converted to high frequency and supplied to the flat plate electrode 21.
The supplied DC voltage was 600V.
The supplied direct current was 2A.
Therefore, the power supply was 1200 W.
The supplied energy per unit area of the to-be-processed film 9 based on the supplied power was (supplied 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, the insulation withstand voltage (V _{9 S} = 4.75 kV) of the film 9 to be processed was set higher (VpVV _9S ).
The peak-to-peak voltage Vpp was Vpp = 15 kV.
The frequency of the applied voltage was 40 kHz.

Bonding process
The sample piece was cut out from the to-be-processed film 9 surface-treated as mentioned above, and the adhesive agent was apply | coated to this. As an adhesive, a room temperature curing epoxy resin was used.
Another sample piece was overlaid on the adhesive-coated sample piece and pressed. The pressure was 10 MPa, and the pressure time was 3 hours.

<Evaluation>
The thus-produced samples were subjected to a peeling test based on fiscal 1999 JIS K6854 to measure the peeling force (adhesive strength) at peeling of both sample pieces.
The measurement result was 4.4 N / inch per inch of the 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 49 slm
H ₂ 1slm
Overall flow rate 50slm
Therefore, the hydrogen content in the process gas was 2 vol%.
The other processing conditions and procedures were the same as in Example 1. The procedures for preparation and evaluation of the sample after 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
Overall flow rate 50slm
Therefore, the hydrogen content in the process gas was 1 vol%.
The other processing conditions and procedures were the same as in Example 1. The procedures for preparation and evaluation of the sample after 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
Overall flow rate 50slm
Therefore, the hydrogen content in the process gas was 0.5 vol%.
The other processing conditions and procedures were the same as in Example 1. The procedures for preparation and evaluation of the sample after 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 has been confirmed that the required adhesion performance (treatment performance) can be obtained if the hydrogen content in the process gas is 0.5 vol% or more. The higher the hydrogen content in the process gas within the explosive limits, the better 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 film 9 to be processed was 3.6 seconds. Further, the energy supplied from the power source 2 was (supply power) × (treatment time) / (discharge area) = 225 kJ / m ² per unit area of the film 9 to be treated.
The other processing conditions and procedures were the same as in Example 1. The procedures for preparation and evaluation of the sample after treatment were also the same as in Example 1.
As a result, the adhesive strength was 3.4 N / inch.

In Example 6, the transport speed (processing speed) of the film 9 to be processed was 1 m / min. Therefore, the processing time of each part of the to-be-processed film 9 was 1.8 second. Further, the energy supplied from the power supply 2 was (supply power) × (treatment time) / (discharge area) = 112.5 kJ / m ² per unit area of the film 9 to be treated.
The other processing conditions and procedures were the same as in Example 1. The procedures for preparation and evaluation of the sample after 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 is also affected by the supplied energy. If the energy supplied from the power source 2 is 115 kJ / m ² or more per unit area of the film 9 to be treated, sufficient processing performance (adhesiveness) can be secured in consideration of the variation in measurement.

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

Comparative Example 1
As Comparative Example 1, the insulation withstand voltage of the film 9 to be treated was increased by increasing the thickness of the film 9 to be treated made of polytetrafluoroethylene (PTFE). Specifically, the thickness t _{9 of the} film 9 to be treated was set to t ₉ = 500 μm which is twice that of Example 1. Therefore, the insulation withstand voltage V _{9 S} of the film 9 to be processed was V _{9 S} = 9.5 kV. Therefore, the voltage applied between the electrodes 21,11 (Vp = 7.5kV) is lower than the insulating withstand voltage _{V 9S} of the processed film 9 _{(Vp <V} 9S).
Furthermore, the supply DC voltage of the power supply 2 is set to 600 V, and the supply DC current is set to 1.6 A, so that the supply DC power is set to 960 W. Therefore, the supplied energy per unit area of the film 9 to be processed based on the supplied DC power was about (supplied power) × (processing time) / (discharge area) = 300 J / m ² .
The other processing conditions and procedures were the same as in Example 1. The procedures for preparation and evaluation of the sample after 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 to be treated made of polytetrafluoroethylene (PTFE) was t ₉ = 400 μm. Therefore, the insulation withstand voltage V _{9 S} of the film 9 to be processed was V _{9 S} = 7.6 kV.
Further, 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 _{V9S of the} film 9 to be processed (Vp < _V9S ).
Furthermore, the supply DC power of the power supply 2 was set to 1000 W by setting the supply DC voltage of the power supply 2 to 600 V and the supply DC current to 1.67 A. Therefore, the energy supplied per unit area of the film 9 to be processed based on the supplied DC power was (supply power) × (treatment time) / (discharge area) = 312.5 J / m ² .
The other processing conditions and procedures were the same as in Example 1. The procedures for preparation and evaluation of the sample after 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 insulation withstand voltage _V9S (Vp ≧ _V9S ), the desired processing performance can be obtained, while the applied voltage Vp falls below the insulation withstand voltage _V9S of the film 9 to be processed. To the extent (Vp <V _{9 S} ), it was difficult to obtain the 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 is set to 0 vol%.
The other processing conditions and procedures were the same as in Example 1. The procedures for preparation and evaluation of the sample after treatment were also the same as in Example 1.
As a result, the adhesive strength was 0.7 N / inch.
From Example 1 and Comparative Example 3, it was confirmed that it is important to contain hydrogen in the process gas in order to obtain the 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 higher than the insulation withstand voltage of the film 9 to be processed between the electrodes 21 and 11, It has been confirmed that adhesion can be improved.

  The present invention can be applied, for example, to improve the adhesion of a film made of a fluorine-based resin such as polytetrafluoroethylene (PTFE) and to bond it to a member to be adhered.

1 film surface treatment apparatus 1a treatment space 2 power supply 3 process gas supply source 9 fluorine resin film (film to be treated)
11 Roll electrode (ground electrode)
13 Transport mechanism 21 Flat plate electrode (voltage application electrode)
21a Discharged Surface 31 Process Gas Nozzle

Claims (3)

A method of surface treating a film to be treated comprising a fluorine-based resin,
Conveying 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 generating step of generating a discharge in the processing space by applying a voltage higher than the insulation withstand voltage of the film to be processed between the pair of electrodes;
Cutting the C—F bond of the surface molecules of the film to be treated by the gas supply step and the discharge generation step to form a C—H bond;
Only containing, hydrogen content of the process gas is, the film surface treatment method which is a 0.5vol% ~4vol%. Supplying energy to the electrode from a power source in the discharge generation step, the film surface treatment method according to claim 1, characterized in that the 115kJ ^/ m ² ~1000kJ / m 2 per unit area of the processed film. An apparatus for surface treating a film to be treated comprising a fluorine-based resin,
A pair of electrodes defining a processing space near atmospheric pressure between each other and generating 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 insulation withstand voltage of the film to be treated, breaking the C—F bonds of surface molecules of the film to be treated to form C—H bonds, in the process gas hydrogen content of the film surface treatment apparatus according to claim der Rukoto 0.5vol% ~4vol%.

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