JPS5986633A - Process and apparatus for plasma treatment - Google Patents

Abstract

PURPOSE:To make it possible to carry out the simultaneous and uniform treatment of a number of objects to be treated, which is carried out as a prepainting treatment of large resin parts of complicated shapes, by irradiating the objects with both radiowave discharge plasma and microwave discharge plasma in a plasma reaction chamber. CONSTITUTION:A number of objects to be treated (e.g., polypropylene molded parts) are set within a reaction chamber 11. A plasma generating gas (e.g., O2) introduced from gas inlets 13-1-3, 14-1-3, and 15-1-3 is excited by the high-frequency energy generated between an electrode plate 12 connected to a high-frequency electric power source and the wall of the reaction chamber and generates radiowave discharge plasma, with which the surfaces of objects near the electrode plate 12 are treated uniformly. On the other hand, the high- frequency waves generated in a microwave oscillator causes a gas (e.g., O2) to generate plasma in a plasma generating tube. This plasma is led to the inlets of the reaction chamber 16-1-3 and 17-1-3, and distributed through shower tubes 31-1-3 and 32-1-3 and is used to treat parts which are distant from the electrode plate 12 or which the radiowave discharge plasma can hardly reach because of interruption by objects.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to resins, such as polypropylene (PP).
), polyethylene (PE), etc., and relates to a method and apparatus for subjecting the surfaces of these resins to plasma treatment in order to modify the surfaces thereof. The present invention can be effectively used as a pretreatment for painting a relatively large and complicatedly shaped resin part.

In recent years, for example, there has been a trend toward using resins for automobile parts, which are lightweight and have excellent designs, but relatively inexpensive PP
When using , PE, etc., for example as a vehicle outer panel, it is known that the adhesion between the resin surface and the coating film is poor, resulting in problems such as delamination. One way to solve this problem is to expose the entire surface of the object to be coated (PP, PE, etc.) to glow, corona, radio waves, or fibrous discharge before painting to oxidize (introduce polar groups) or etch (introduce polar groups) the surface. Plasma treatment technology that improves the anchoring effect is known.

By the way, when performing plasma processing, in order to improve the processing effect (2) (lengthen the life of the plasma), it is necessary to reduce the volume of the reaction chamber or to place it in a vacuum state.

In order to maintain this state, patch processing is currently the mainstream.

In order to introduce this processing method into the mass production process of manufacturing automobile parts, it is necessary to reach a vacuum state in a short time and to plasma-process a large number of objects at one time.

Taking these points into consideration, we have developed relatively large and complex-shaped resin parts (polypropylene: PP) used in automobile parts.
'e, radio wave discharge plasma treatment and microwave number 'K
When various f-lasma treatments were used separately, the following points became clear.

A. Radio frequency electric plasma processing [Processing apparatus] Figure 5 shows an apparatus for radio wave discharge plasma processing. Due to the high frequency energy generated between the electrode plate 22 in the reaction chamber 21 connected to the high frequency power supply 25 and the grounded wall of the reaction chamber 21, the plasma generation gas introduced from the gas inlet ports 23-1 to 23-3, e.g. The oxygen is excited and becomes radio frequency discharge plasma 30. In Fig. 5, 24H vacuum degree adjustment pulp is shown, and 26-1 to 7 are resin treated objects (pp).
It is.

Furthermore, a, b, and c are surfaces (parts) of each object to be processed. The processing conditions are as follows.

[Processing conditions]

Reaction chamber size: 1900 mm diameter x 1900 mm Soar wave frequency: 13.56 MH2 output
: 500W True pressure : 0.5 Torr processing gas (amount)
: Oxygen (500OW min) treatment time
The results of such radio wave discharge plasma treatment for 30 seconds are shown in FIGS. 6 and 7. In addition, the contact angle measurement method and the treatment object temperature measurement method are as follows.

[Contact angle measurement method]

5 μ of deionized water was dropped onto the plasma-treated PP surface, and the contact angle was measured using a contact angle measuring device (Model CA-A, manufactured by Kyowa Kagaku) (20° C., 50-60 μm atmosphere).

Each point in FIG. 6 represents each part a of each workpiece 26-1 to 70,
It is an average value of five measurements of the contact angle in b and c.

[Workpiece temperature measurement method]

Using Temp Grate (W, manufactured by WAHI, Inc.), the temperature at which the PPfi surface rose to the maximum during plasma treatment was measured.

〔Strong Points〕

Since the plasma concentration generated at the electrode plate 22 in the reaction chamber 21 is relatively uniform, objects to be processed, such as 26-1t26-z*26-3e26-s, are placed near the electrode plate 22.

26-6126-7, as shown in FIG. 6 as a region surrounded by a broken line, there is little difference in processing depending on the placement position.

[Disadvantages]

a) The distance between the glazma generation site and the surface to be treated is the 6th
As shown in the workpiece 26-4 in the figure, increasing the output (up to 100 OW as shown in Figure 7) to correct items b) and a) has a large effect on processability. There is a concern that the temperature of the object to be processed near the plasma generating part will increase, and that the resin will be thermally deformed.

B. Microwave Discharge Plasma Treatment [Processing Apparatus] FIG. 8 shows an apparatus for microwave discharge plasma processing. High frequency waves generated by a microwave oscillator (not shown) are introduced into a plasma generation tube (not shown) to turn gas, such as oxygen, supplied from another route (not shown) into plasma.

Plasma generated in a generation tube (not shown) passes through a quartz tube (not shown), is introduced into an inlet 26 of the reaction chamber, and is irradiated into the reaction chamber through a Java tube 27. In Figure 8, 2
8 is a valve for adjusting the degree of vacuum, and 29-1 to 7 are resin objects to be processed (pp). Also, a, b.

C is a surface (part) of each object to be processed.

[Processing conditions]

Reaction chamber size: 1900mm diameter x 1900wm
Long microwave frequency: 2450MH2 output
: 500W Vacuum pressure: 0.5 Torr Processing gas (amount): Oxygen (50oW min) Processing time
The results of such microwave discharge plasma treatment for =30 seconds are shown in FIG. Note that the contact angle measuring method is the same as in the case of the radio wave discharge plasma treatment described above. Each point in FIG. 9 represents each part a of each object to be processed 29-1 to 29-7.

It is an average value of five measurements of the contact angle in b and e.

〔Strong Points〕

a) As shown by the object to be treated 29-4 in FIG. 9, the distance between the irradiation site and the surface to be treated in the plasma irradiation direction has a small influence on the plasma processability.

b) From this, it is possible to selectively target and treat areas that are difficult to treat with radio wave discharge 1 plasma.

[Disadvantages]

a) As shown by the broken line in Figure 9, the plasma has poor diffusion, and in order to uniformly treat all the objects in the reaction chamber, the number of plasma introduction ports and irradiation areas must be increased. This is necessary.

b), Workpiece 29-5 +29-5t29- in Fig. 9
As shown by 6t29-7, the processability is poor in the shaded areas of the irradiation area due to the shielding effect of the object to be processed.

As described above, it has been found that plasma processing of either radio waves or microwaves at 10,000 times is not sufficient to simultaneously process a large number of relatively large resin parts with complex shapes.

The purpose of the present invention is to apply plasma treatment to a relatively large resin part made of resin, such as polypropylene (PP) or chiliethylene (PE), and to treat a large number of parts to be treated before painting. To provide a method and apparatus for performing grain size processing, which can ensure uniform processing performance for each object to be processed even if the objects are processed simultaneously. In particular, the present invention provides a plasma processing method and apparatus that can take advantage of the advantages of both radio wave discharge plasma processing and microwave discharge plasma processing.

The plasma treatment method of the present invention that achieves the above purpose includes (7) radio wave discharge plasma and microwave discharge plasma in a method of treating the surface of a workpiece by irradiating plasma in a plasma reaction chamber. It is characterized by irradiating the object to be treated.

In addition, the apparatus for performing plasma processing of the present invention is an apparatus for irradiating plasma onto the surface of an object to be treated in a plasma reaction chamber. It is characterized in that an introduction port for introducing microwave discharge plasma into the reaction chamber is provided, and an introduction port for introducing microwave discharge plasma into the reaction chamber is provided at an arbitrary position of the pond.

In this case, it is desirable that the introduction port for the microwave discharge plasma be installed toward a region that cannot be sufficiently reached by the radio wave discharge plasma.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 to 3 show an apparatus for applying glazma treatment according to the present invention. The reaction chamber 11 is a substantially cylindrical sealed container, and a substantially cylindrical electrode plate 12 is provided adjacent to the inner wall of the reaction chamber 11 , and this electrode plate 12 is connected to a high frequency power source 20 .

The electrode plate 12 is formed of a mesh (8) or a perforated plate in order to circulate the glazization gas inside the reaction chamber 11. Three gas inlet ports 13-1 to 13-3 for radio wave discharge plasma generation are provided at equal intervals in the axial direction on the wall of the reaction chamber 11, and the same three gas inlet ports 13-1 to 3-3 are provided at positions rotated by 90 degrees. Gas inlets 14-1 to 3t and 15-1 to 15-3 for radio wave frequency electricity are provided. In addition, these gas inlet ports 13-1 to 3 for radio wave discharge
．． 14-1 to 30 questions and 14-1 to 3.15-1 to 3
In between are respective microwave discharge plasma introduction ports 16.
-1 to g and 17-1 to 3 are provided. Java tubes 31-1 to 5*32-1 to 3 are connected to these introduction ports 16-1 to 16-1 to 17-1 to 3, respectively. 18-
1 to 3. 19-1 to 5+20-1 to 3 are valves for adjusting the degree of vacuum, and maintain the inside of the reaction chamber 11 in a reduced pressure state during the reaction process. Although the objects to be treated (polycropylene molded parts) in the reaction chamber 11 are not shown, they can be arranged in the same manner as the objects to be treated shown in FIG. 5 or FIG. 8. Due to the high frequency energy generated between the electrode plate 12 in the reaction chamber 11 connected to the high frequency power supply 20 and the wall of the reaction chamber 11 which is grounded,
The plasma-forming gas, such as oxygen, introduced from -1 to g and 15-1 to 3 is excited and becomes radio wave discharge plasma. The purpose of this discharge method treatment is to
The purpose is to uniformly treat the surface of the nearby object to be treated, that is, the general surface of the product.

10,000, high frequency waves generated by a microwave oscillator (not shown) are introduced into a plasma generation tube (not shown), and are passed through a separate route (
A gas, such as oxygen, supplied from a source (not shown) is glazed. Glazma generated in the generation tube (not shown) is
Pass through a quartz tube (not shown) and enter the reaction chamber inlet 16-1~
3.17-1 to 3, and Java tubes 31-1 to 3.
32-1 to 32-5. The purpose of this discharge method treatment is to shield areas that have not been sufficiently treated by the radio wave discharge plasma treatment, in other words, to cover and shield objects that are far away from the electrode plate 12 in the reaction chamber 11. The aim is to treat areas that are difficult for discharge plasma to reach.

[Processing conditions]

Reaction chamber size: 1900m diameter x 1900m length (
Material) (Made of SUS 304) [Radio wave discharge plasma treatment] Laso wave frequency: 13.56MH2 output
: 500W Vacuum pressure : 0.5 Torr processing capacity (amount)
: Oxygen (5000 yen) treatment time
:30 seconds [Microwave discharge plasma treatment] Microwave frequency: 2450MH.

Output: 500W Vacuum pressure: 0.5 Torr processing gas (
Amount): Oxygen (5000ν minutes) treatment time
: The results of actual processing under processing conditions such as 30 seconds or more are shown in the fourth section.
As shown in the figure. The arrangement of the objects to be processed (pp) is the same as that shown in FIG. 5, and each object to be processed is indicated by 26-1 to 26-7. Each point in FIG. 4 is the average value of five measurements of the contact angle at each part a, b, and c of each workpiece. Further, the method for measuring the contact angle is the same as that described above. As is clear from the results in FIG. 4, the workpiece 2 was subjected to both radio wave discharge plasma treatment and microwave discharge plasma treatment according to the present invention
It can be seen that in samples 6-1 to 6-7, the variation in processability among the objects to be processed or between the parts a, b, and e of the same object to be processed was reduced.

In addition, in the treatment of the above example, microwave discharge plasma treatment is performed after Lanau wave discharge plasma treatment, and the results are shown as preliminary results.
Even if the processing order is changed or the processing is performed simultaneously, the effect remains the same. Therefore, as long as it does not depart from the spirit of the present invention, the embodiments of fll+ that can be conceived based on the knowledge of those skilled in the art may also be adopted as appropriate.

[Brief explanation of drawings]

FIG. 1 is a side view of an apparatus for performing plasma processing according to the present invention, FIG. 2 is a sectional view thereof, and FIG.
A side view of the apparatus of the present invention when rotated by 0°, Figure 4 is a diagram showing the quality (contact angle) of the object to be treated when treated according to the present invention, and Figure 5 is a diagram showing only radio frequency electroplasma treatment. A cross-sectional view of the device, FIGS. 6 and 7 are diagrams showing the quality (contact angle) of the processed material and the temperature of the processed material when processed using the device shown in FIG. 5, respectively, and FIG. FIG. 9 is a cross-sectional view of an apparatus that performs only microwave discharge plasma treatment, and is a diagram showing the quality contact angle of the object to be treated when treated with the apparatus of FIG. 8. 11... Reaction chamber, 12... Electrode plate, 13-1 to 5.1
4-1~3゜15-1~3...Lasso wave discharge plasma inlet 116-1~3, 17-1~3...Microwave discharge plasma inlet, 31-1~3 .32-1
~3...Glass tube. Patent Applicant Toyota Motor Corporation Patent Application Agent Akira Aoki Patent Attorney Kazuyuki Nishidate Patent Attorney Soto Higuchi Patent Attorney Akira Yamaguchi
■Round powder

Claims (1)

[Claims] 1. A method of treating the surface of a workpiece by irradiating plasma in a plasma reaction chamber, characterized in that the workpiece is irradiated with radio wave discharge plasma and microwave discharge plasma. , a method of applying plasma treatment. 2. In an apparatus that processes a surface of a workpiece by irradiating plasma in a reaction chamber, an inlet for introducing a radio wave discharge plasma gas into the reaction chamber is provided at an arbitrary position in the reaction chamber, and An apparatus for performing plasma processing, comprising an inlet for introducing microwave discharge plasma into the reaction chamber at any other position. 3. The apparatus according to claim 2, wherein the introduction port for the microwave discharge plasma is installed toward a region where the radio wave discharge plasma cannot sufficiently reach. (1).