JPH0315531Y2 - - Google Patents

Description

[Detailed explanation of the idea]

[Industrial Application Field] The present invention relates to a plasma processing apparatus for resin molded products. [Prior Art] Molded products made of olefin resins such as polypropylene and polyethylene are inferior in paint film adhesion due to their non-polar properties. Therefore, these resin molded products are subjected to surface modification by irradiating them with so-called cold plasma, which is obtained by exciting gases such as air, oxygen, argon, helium, etc. using microwaves. There is. The plasma processing is performed by storing the object to be processed in a chamber, reducing the pressure inside the chamber, introducing plasma from a plasma generator into the chamber, and irradiating the object to be processed. There is a problem in that when the process is carried out with the object stationary in the chamber, the process becomes uneven. Therefore, (1) a method in which multiple plasma shower tubes are installed and plasma irradiation is performed from multiple directions, (2) a method in which multiple exhaust pipes are installed and plasma irradiation is diffused by the suction force on the exhaust side, (3) A method in which the object to be treated is mounted in an appropriate frame and irradiated with plasma while the object to be treated revolves and/or rotates within the chamber (see Japanese Patent Laid-Open No. 58-208326); and (4)
A method has been proposed in which a fan is provided in the chamber and plasma is diffused through the fan. (Problems to be solved by the invention) However, among the above methods, (1) the method of installing multiple plasma shower pipes and (2) the method of installing multiple exhaust pipes each have the problem that the piping becomes complicated. In addition, (3) the method of rotating the object to be processed requires a rotation drive device, which complicates the device, and (4) the method of diffusing the plasma with a fan requires the plasma to flow into the fan. There is a problem that the plasma becomes lifeless due to the collision. SUMMARY OF THE INVENTION In view of the above-mentioned points, the present invention provides a plasma processing apparatus capable of uniformly processing a workpiece with a simple configuration. [Means for solving the problem] The present invention is a plasma processing apparatus for surface modification of a resin molded product housed in a vacuum chamber by irradiating plasma with a rotating type that generates turbulence in the vacuum chamber. The present invention relates to a plasma processing apparatus characterized in that it is provided with a plasma shower tube. [Example] Next, the apparatus of the present invention will be explained based on the drawings. Fig. 1 is a schematic explanatory diagram showing an embodiment of the plasma processing apparatus of the present invention, Fig. 2 is an enlarged sectional view taken along the line X-X of Fig. 1, and Fig. 3 is a rotational diagram used in the plasma processing apparatus of the present invention. 1 is a plan view of an embodiment of a type plasma shower tube. In FIG. 1, 1 is a vacuum chamber for processing a workpiece. 3 is a gas cylinder for air, oxygen, argon, helium, etc., and the gas is sent from the cylinder 3 through a pipe 4 to a plasma generator 5, where it is excited by microwaves from a microwave generator 6 and becomes a plasma state. The generated plasma is introduced into the chamber from the plasma discharge port 8 of the rotating plasma shower tube 7 and irradiated onto the object 9 to be processed. Reference numeral 10 denotes an exhaust port provided in the vacuum chamber 1, which is connected to a vacuum pump for maintaining the inside of the chamber 1 at a predetermined degree of vacuum. 2 is a drive device for rotating the plasma shower tube 7. In the plasma processing apparatus, plasma is irradiated from a rotating plasma shower tube 7 provided in the upper part of the vacuum chamber 1. At this time, the rotation of the plasma shower tube 7 generates turbulence within the vacuum chamber 1 and diffuses the plasma, so that the object to be processed is uniformly irradiated. This can be made more effective by providing an exhaust port 10 at a position facing the plasma shower tube 7 and generating an airflow across the vacuum chamber 1. The plasma shower tube 7 may be rotated in one direction, or may be rotated alternately in forward and reverse directions. The rotation conditions for generating turbulence vary depending on the position and number of plasma discharge ports 8, but a rough guideline is 60 to 80 rotations/minute. In addition, the number of branches at the tip of the plasma shower tube 7 is
In addition to the four-branch type shown in FIG. 3, a three-branch type, a five-branch type, etc. can be used as appropriate. Next, the results of a test on the adhesion of the resulting coating film, which was performed by coating a treated object that had been subjected to plasma treatment using the apparatus of the present invention, will be shown. EXAMPLE A bumper cover having a substantially U-shaped cross section was molded from polypropylene and subjected to plasma treatment using the apparatus shown in FIG. The processing conditions are as follows. Number of branch pipes of plasma shower tube: 4 branches Number of plasma discharge ports per branch pipe: 5 Vacuum chamber pressure: 1.0 Torr Gas: O ₂ gas flow rate: 400 to 600 ml/min Microwave generation output: 0.5 KW Processing time: 10 seconds Urethane paint (R-263, manufactured by Nippon B Chemical Co., Ltd.) was applied to the outer surface of the plasma-treated bumper cover, and baked at 80° C. for 1 hour to form a coating film with a thickness of 35 μm. The adhesion of the resulting coating film was examined by a cross-cut peel test (JIS K 5400). The results are shown in Table 1. In Table 1, the front, upper, and lower surfaces respectively refer to the front, upper, and lower surfaces of the bumper cover, which has a generally U-shaped cross section. Comparative Example Plasma treatment was performed in the same manner as in the example except that the plasma shower tube 7 was not rotated, and then painting was performed, and the adhesion of the resulting paint film was examined. The results are shown in Table 1.

〔effect〕

As explained above, the present invention has the effect that the object to be treated is uniformly treated by the turbulence generated by the rotation of the plasma shower tube.

[Brief explanation of the drawing]

Fig. 1 is a schematic explanatory diagram showing an embodiment of the plasma processing apparatus of the present invention, Fig. 2 is an enlarged sectional view taken along the line X-X of Fig. 1, and Fig. 3 is a rotational diagram used in the plasma processing apparatus of the present invention. 1 is a plan view of an embodiment of a type plasma shower tube. Main symbols in the drawing: 1: Vacuum chamber, 2: Drive device, 5: Plasma generator, 7: Plasma shower tube, 9: Processed object, 10: Exhaust port.

Claims (1)

[Scope of utility model registration request] A plasma processing apparatus for surface modification of a resin molded article housed in a vacuum chamber by irradiating it with plasma, characterized in that a rotating plasma shower tube is provided to generate turbulence in the vacuum chamber. Device.