JP2019061869A - Plasma surface processing method and plasma surface treatment device - Google Patents

Abstract

To provide a plasma surface processing method and a plasma surface treatment device which are suitable for a surface treatment on an inner face of a tubular workpiece, and particularly enable an easy and reliable surface treatment on an inner face of an elongated workpiece or a workpiece of a small inner diameter.SOLUTION: A plasma surface processing method for performing a surface treatment on an inner face of a tubular workpiece W comprises the step of putting the workpiece W between opposing electrodes 2 with a high-frequency power put therebetween while introducing a process gas into the tube of the workpiece W. In the method, a gas easier to glow discharge than a gas interposed between the opposing electrodes 2 is used as the process gas; the glow discharge is caused only in the tube of the workpiece W without causing discharge between the opposing electrodes 2. In this way, the process gas in the tube is turned to plasma which is brought into contact with the inner face of the workpiece W, thereby performing the surface treatment on the inner face of the workpiece W.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a plasma surface treatment method and a plasma surface treatment apparatus, and more particularly to a technique for applying a surface treatment to the inner surface of a tubular object to be treated.

  Recently, for the purpose of improving various performances such as hydrophilicity and water repellency of the object to be treated, a surface treatment method has been proposed by contacting the surface of the object to be treated with plasmad (plasma activated) treatment gas. (See, for example, Patent Document 1).

  By the way, when performing surface treatment on the inner surface of a tubular object to be treated such as a pipe or tube using such a surface treatment method, conventionally, a method of introducing a processing gas converted into plasma from one end of the object into the tube Is used.

Japanese Patent Application Publication No. 2002-237480

However, such surface treatments have the following problems, and their improvement has been desired.
That is, according to the method of introducing the processing gas which has been plasmatized into the tube from one end of the object to be treated, the processing gas excited by the plasmatization is introduced into the tube and contacts the inner surface (inner wall surface) inside the tube. Although the inner surface of the treatment body is subjected to surface treatment, for example, components having a short life, such as oxygen radicals in the treatment gas, disappear at a relatively short distance from the end of the tube, There is a problem that it can not be applied to the surface treatment of the inner surface of a long object to be treated. For example, when the pipe length is several meters or more, it has been difficult to apply a surface treatment to the entire surface of the pipe.

  Moreover, in the conventional method, even when the inner diameter of the object to be treated W is small, the surface treatment of the inner surface is difficult. That is, for example, in the case of a tube such as a catheter, there is one having an inner diameter of several mm or less (for example, 0.5 mm or 1 mm). There is a tendency for the route to introduce it to be longer. Therefore, at the time when the processing gas converted into plasma is introduced into the tube, many components (for example, oxygen radicals etc.) effective for surface treatment may have already been lost, and a sufficient surface treatment effect can not be obtained. There was a thing.

  The present invention has been made in view of such problems, and the object of the present invention is suitable for surface treatment of the inner surface of a tubular object to be treated, and in particular, a long object to be treated and a small inner diameter. It is an object of the present invention to provide a plasma surface treatment method and a plasma surface treatment apparatus capable of reliably and easily performing the surface treatment of the inner surface of an object to be treated.

  In order to achieve the above object, a plasma surface treatment method according to the present invention is a plasma surface treatment method for subjecting the inner surface of a tubular object to be treated to a surface treatment, wherein a treatment gas is introduced into a tube of the object. By disposing the object between the opposing electrodes to which high frequency power is applied, the processing gas present in the tube of the object is plasmatized to be in contact with the inner surface of the object, The surface treatment is applied to the inner surface of the object to be treated.

  And as a preferred embodiment thereof, the processing gas is characterized by using a gas which is more likely to be plasmatized by the application of high frequency power than the gas interposed between the counter electrodes.

  In another preferred embodiment, air is interposed between the counter electrodes, and helium or a mixed gas of helium and another gas is used as the processing gas.

  In another preferred embodiment, a mixed gas in which air is interposed between the counter electrodes and helium is mixed with a fluorine-based gas is used as the processing gas.

  Further, as another preferred embodiment, by continuously introducing the object to be processed in a state in which the processing gas is introduced into the tube between the counter electrodes, the inner surface of the long object is continuous. Surface treatment.

  Further, a plasma surface treatment apparatus according to the present invention is a plasma surface treatment apparatus for subjecting the inner surface of a tubular object to be treated to a surface treatment, the counter electrode to which high frequency power is applied, and a tube of the object to be treated. And a carrier means for carrying the processing object, into which the processing gas has been introduced, between the counter electrodes.

  According to the present invention, the object to be treated in a state in which the process gas is introduced into the tube is disposed between the opposing electrodes to which the high frequency power is applied. The inner surface of the object to be treated is subjected to surface treatment while being in contact with the inner surface of the object to be treated.

  As described above, in the present invention, since the processing gas is plasmatized in the tube of the object to be treated, components effective for surface treatment contained in the processing gas are allowed to act on the inner surface of the object before disappearing due to the life. be able to. Therefore, it is possible to reliably and easily carry out surface treatment on the inner surface of a long object to be treated or an object having a small inner diameter without leakage.

It is the perspective view which showed typically an example of schematic structure of the plasma surface treatment apparatus which concerns on this invention. FIG. 2 is a cross-sectional view schematically showing a cross section of the plasma surface treatment apparatus. It is explanatory drawing which shows an example of the point which glow discharge generate | occur | produces by application of high frequency electric power. It is the perspective view which showed typically another example of the plasma surface treatment apparatus.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.
Embodiment 1
1 and 2 show an example of a plasma surface treatment apparatus 1 according to the present invention. The plasma surface treatment apparatus 1 shown in these figures is a surface treatment apparatus suitable for surface treatment of the inner surface of a tubular object to be treated W.

  Specifically, in the plasma surface treatment method according to the present invention, the treatment gas is introduced into the tube of the treatment object W during the treatment of the treatment object W, and the treatment is performed between the opposing electrodes to which the high frequency power is applied. By arranging the body W, the processing gas present in the tube of the object W is plasmatized and brought into contact with the inner surface of the object W, whereby the inner surface of the object W is subjected to surface treatment The plasma surface treatment apparatus 1 is configured as an apparatus for carrying out the plasma surface treatment method.

  Here, as a tubular object to be treated W to be subjected to surface treatment using the plasma surface treatment apparatus 1 according to the present invention, for example, a hollow tube such as a pipe or a tube is exemplified. Moreover, as a material of the to-be-processed object W, what was comprised with insulators, such as resin, such as a natural resin and a synthetic resin, and inorganic dielectric materials, such as glass and ceramics, is used.

  The plasma surface treatment apparatus 1 is an apparatus mainly used under the atmospheric pressure or a pressure environment near the atmospheric pressure, and supplies the processing gas into the counter electrode 2 to which high frequency power is applied and the tube of the object W to be processed. A gas supply means 3 is provided as a main part.

  The counter electrode 2 is an electrode for applying high frequency power to the object to be processed W into which the processing gas is introduced into the tube, and is electrically grounded with the voltage application electrode 2a to which the high frequency power source 4 is connected. And the ground electrode 2b. In the present embodiment, a parallel plate type electrode in which both electrode facing surfaces of the high frequency electrode 4 and the ground electrode 5 are formed in a flat plate shape is adopted as the counter electrode 2. The distance between the opposing electrodes 2 (the distance between the opposing electrodes 2) is appropriately set in relation to the high frequency power applied to the opposing electrodes 2. That is, as described later, in the present invention, since glow discharge is generated in the tube of the object to be processed W disposed between the opposing electrodes 2, the distance between the opposing electrodes 2 is a high frequency applied between the opposing electrodes 2 It is set to the sense that glow discharge can occur at least in the tube of the object to be treated W in relation to the electric power (applied voltage or the like).

  Here, in the present invention, as described above, the object to be treated W is made of an insulator, so in the plasma surface treatment apparatus 1 shown in the present embodiment, both the voltage application electrode 4 and the ground electrode 5 are provided. The electrode opposing surface adopts an electrode having a structure in which the metal constituting the electrode is exposed. Of course, the electrode facing surface of either or both of the voltage application electrode 4 and the ground electrode 5 may be covered with a dielectric such as ceramic or glass.

  The gas supply means 3 is a means for supplying the processing gas into the pipe from the opening of the pipe end of the body W to be processed, and more specifically, it is a supply source of the processing gas such as a gas cylinder or the like. It comprises an inlet for guiding the introduction of processing gas into the opening.

  Here, the processing gas will be described. The treatment gas to be used is appropriately selected according to the content of the surface treatment (for example, hydrophilization treatment, water repellent treatment, etc.), but in the present invention, it is more plasmatized than at least the gas interposed between the counter electrodes 2. An easy gas is used as the processing gas.

  As described above, in the present invention, the processing gas is plasmatized in the tube by arranging the object W in a state in which the processing gas is introduced into the tube between the opposing electrodes to which the high frequency power is applied. It is necessary to generate glow discharge in the tube prior to the space between the electrodes 2. Therefore, as the processing gas, by applying high frequency power between the opposing electrodes 2, a gas which generates glow discharge in the tube earlier than the gas interposed between the opposing electrodes 2, ie, intervenes between the opposing electrodes 2 A gas is used that is more likely to cause plasma formation associated with glow discharge than gas.

  FIG. 3 exemplifies the generation point of the glow discharge accompanying the application of the high frequency power, according to the type of gas (gas type). It is known that when high frequency power is applied between electrodes in which a gas intervenes, as shown in FIG. 3, the point (applied power) at which glow discharge occurs is different for each gas. That is, as illustrated, when helium (He), argon (Ar), and air (Air) are compared, helium glows at the lowest power (that is, it is most likely to cause glow discharge), and then , Argon, and finally, air is known to glow (the air is the most difficult to glow). In the present invention, focusing on the difference in the generation point of the glow discharge for each gas, the gas that generates the glow discharge in the tube earlier than the gas interposed between the counter electrodes 2 is adopted as the processing gas. .

  Specifically, for example, when air intervenes between the counter electrodes 2, helium, argon, helium or the like and other gases (such as helium or argon) are introduced as the processing gas introduced into the tube of the object W For example, a mixed gas with air such as CDA or nitrogen) is used. Incidentally, when a mixed gas is used as the processing gas, a mixed gas containing the largest amount of helium or argon is used so that glow discharge is generated in the tube before the space between the counter electrodes 2.

In addition, when the treatment gas is classified based on the contents of the surface treatment, for example, when performing a hydrophilization treatment, helium, argon, or these helium etc. and other gases (eg air such as CDA or nitrogen) as the treatment gas Etc.) is used. In contrast, when performing the water repellent treatment, helium mentioned above, a mixed gas of argon or these and other gases, the fluorine-based gas (e.g., tetrafluoromethane (CF _4), hexafluoroarsenate A mixed gas of fluorinated ethane (C ₂ F ₆ ), propane octafluoride (C ₃ F ₈ ) and trifluoromethane (CHF ₃ )) is used. Even in the case of mixing a fluorine-based gas, a mixed gas containing most helium or argon is used.

  Next, the surface treatment procedure of the inner surface Wc of the object to be treated W using the plasma surface treatment apparatus 1 will be described with reference to FIGS. 1 and 2.

  FIG. 1 shows the case where surface treatment is performed in a state in which a long workpiece W is wound in a spiral shape. Moreover, in this embodiment, the case where plasma surface treatment apparatus 1 is used under atmospheric pressure (normal pressure) environment is shown. Therefore, the space between the opposing electrodes 2 is filled with air.

  As shown in FIG. 1, the object to be processed W is disposed such that its tip and base end are located outside of the space between the opposing electrodes 2 and the other portion is located between the opposing electrodes 2. FIG. 2 is a cross-sectional view showing the state of the object to be treated W disposed between the counter electrodes 2. As shown in this figure, in the present embodiment, the object to be treated W is placed on the ground electrode 2b. Be done. In the present embodiment, the case where the object to be treated W is placed on the ground electrode 2b (in a contact state) is shown, but if the object to be treated W is disposed between the counter electrodes 2, the voltage It may be arranged in a floating state between the opposing electrodes 2 without being in contact with the application electrode 2a or in contact with both the voltage application electrode 2a and the ground electrode 2b.

  Then, in this state, the gas supply unit 3 is connected to the base end Wb of the object to be processed W, and the processing gas is introduced from the gas supply unit 3 into the pipe of the object to be processed W. At this time, the process gas is introduced so as to fill the entire tube of the object W to be treated. That is, in the object W to be processed, the processing gas is introduced such that the air in the tube is replaced with the processing gas at least in a portion disposed between the counter electrodes 2. In the present embodiment, helium is used alone as the processing gas.

  When the tube of the object to be treated W is filled with the treatment gas, next, high frequency power is applied between the counter electrodes 2. In applying the high frequency power, the high frequency power is applied so that glow discharge occurs only in the tube of the object to be treated W. Specifically, according to the processing gas to be used, the glow discharge occurrence point (applied power) is previously obtained by measurement or calculation, and power of the glow discharge occurrence point or more is applied to Generate glow discharge in the tube. The power applied between the opposing electrodes 2 at this time may be equal to or higher than the glow discharge occurrence point, but the upper limit is set so that arcing does not occur at least between the opposing electrodes 2. That is, glow discharge is generated only in the tube of the object W without generating arc discharge between the counter electrodes 2.

  In this way, when glow discharge occurs in the tube of the object W, the processing gas is plasmified along with the glow discharge, and the processing gas converted into plasma contacts the Wc in the tube of the object W, The surface treatment is applied to the inner surface Wc of the object W to be treated.

  As described above, according to the present invention, the surface gas is treated on the inner surface Wc of the object to be treated W by plasmatizing the treatment gas in the tube of the object to be treated W. Can act on the inner surface Wc of the object to be treated before it disappears due to the life. Therefore, even with a long workpiece W or a workpiece W with a small inner diameter, surface treatment can be carried out easily and reliably without leaking the inner surface Wc by filling the tube with the processing gas. It can be applied.

  In the embodiment described above, helium is used as the processing gas. However, argon may be used as the processing gas instead of or together with helium. It is also possible to use a mixture of other gases. Further, as described above, in the case of performing the water repellent treatment, a processing gas to which a fluorine-based gas such as helium is added is used.

Embodiment 2
Next, another embodiment of the present invention will be described based on FIG.
FIG. 4 shows the case where the surface treatment is performed while continuously introducing a long object W to be processed between the counter electrodes, and the plasma surface treatment apparatus 1 shown in FIG. The configuration other than the configuration including the not shown) is common to the first embodiment described above. Therefore, the same reference numerals are given to the parts having the same configuration and the description is omitted.

  In this embodiment, the object to be processed W is introduced between the opposite electrodes 2 from one end side (left side in the drawing) of the opposite electrode 2 and discharged out of the opposite electrode 2 from the other end side (right side in the drawing). The conveyance means (not shown) of the to-be-processed object W is provided, and it is comprised by this conveyance means so that the to-be-processed object W can be continuously introduced between the counter electrodes 2.

  The gas supply means 3 is connected to the base end Wb of the object W to be treated, and the processing gas is introduced from the gas supply means 3 into the pipe of the object W to be treated.

  In the plasma surface treatment apparatus 1 shown in the present embodiment configured as described above, in the surface treatment of the inner surface Wc of the object to be treated W, first, the processing gas in the tube of the object to be treated W from the base end Wb of the object to be treated W Is introduced. Then, when the processing gas is filled in the tube of the object to be processed W, high frequency power is applied between the counter electrodes 2, and the object to be processed W filled with the processing gas is continuously fed between the counter electrodes 2. As a result, when the object W passes between the counter electrodes 2, glow discharge occurs in the tube, and the surface treatment of the inner surface Wc of the object W with the processing gas converted to plasma is performed. It will be discharged.

  That is, in the present embodiment, the surface treatment of the inner surface Wc of the object to be processed W is continuously performed by continuously feeding the object to be processed W in a state in which the processing gas is filled in the pipe between the opposing electrodes 2. It becomes possible. Therefore, for example, the surface treatment of the inner surface Wc can be efficiently performed on a long object to be treated W which exceeds several meters or ten and several meters.

  The embodiment described above is merely a preferred embodiment of the present invention, and the present invention is not limited to these, and various design changes can be made within the scope thereof.

  For example, in the embodiment described above, a parallel plate type electrode is adopted as the counter electrode 2 as the configuration of the plasma surface treatment apparatus 1, but a configuration in which the object W to be processed can be disposed between the counter electrodes 2 The shape of the electrode may not be flat. For example, it is also possible to use an electrode having a shape in which the electrode facing surface is curved.

  In the embodiment described above, the counter electrode 2 is used in the state of being released to the atmosphere. However, for example, a cover that covers both of the counter electrode 2 is provided, and the counter electrode 2 is accommodated in the cover It is also possible to configure. That is, by covering the counter electrode 2 with a cover, it is possible to adopt a method of interposing a gas other than air between the counter electrodes 2, or reducing the pressure between the counter electrodes 2. In that case, it is a matter of course to provide an inlet / outlet for carrying in / out the object W on the cover.

  Moreover, in Embodiment 2 mentioned above, although the case where the to-be-processed object W introduce | transduced between the counter electrodes 2 was one was illustrated, two or more to-be-processed objects W are arranged in parallel, and surface treatment is performed simultaneously in multiple stripes. It is also possible to configure.

DESCRIPTION OF SYMBOLS 1 Plasma surface treatment apparatus 2 Counter electrode 2a Voltage application electrode 2b Grounding electrode 3 Gas supply means W Object to be processed

Claims (6)

It is a plasma surface treatment method of subjecting the inner surface of a tubular object to be treated to a surface treatment,
The processing gas existing in the tube of the object to be treated is converted into plasma by disposing the object to be treated between the opposing electrodes to which the high frequency power is applied while introducing the processing gas into the tube of the object to be treated. A plasma surface treatment method comprising bringing the inner surface of the object to be treated into contact with the inner surface of the object to be treated, thereby treating the inner surface of the object to be treated.   The plasma surface treatment method according to claim 1, wherein the processing gas is a gas that is more easily converted to a plasma by application of high frequency power than the gas interposed between the counter electrodes.   The plasma surface treatment method according to claim 1 or 2, wherein air is interposed between the counter electrodes, and helium or a mixed gas of helium and another gas is used as the processing gas.   The plasma surface treatment method according to claim 1, wherein air is interposed between the counter electrodes, and a mixed gas in which a fluorine-based gas is mixed with helium is used as the processing gas.   The surface treatment is continuously performed on the inner surface of a long object to be treated by continuously introducing the object to be treated in a state in which a processing gas is introduced into the tube between the counter electrodes. The plasma surface treatment method according to any one of claims 1 to 4. A plasma surface processing apparatus for performing surface processing on the inner surface of a tubular object to be treated, comprising:
A counter electrode to which high frequency power is applied;
A gas supply unit for supplying a processing gas into a pipe of the object to be processed;
And a transfer unit configured to transfer the processing object into which the processing gas has been introduced between the counter electrodes.

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