JPS62256840A - Electrode for corona discharge - Google Patents

Abstract

PURPOSE:To perform the corona discharge treatment of an object in high productivity while making allowance for a dispersion of dimensional accuracy, by using a corona discharge electrode constructed by providing a plurality of branches each having a discharge point on its end and extending from a base in parallel with each other. CONSTITUTION:A corona discharge electrode 50 is constructed by planting a plurality of cylindrical branches 52 each having a discharge point 52a on its end and having the same length on the lower surface of the branch base member 51b of a base 51 formed of a cylindrical base body 51a which is connected with a leadwire extending from a high-frequency application means and the plate branch base member 51b joined with the branches at an angle normal thereto so that the branches may be in parallel with each other and may be spaced at approximately equal intervals. A molding 1 such as an automobile interior trim made of PP resin is set on a counter electrode means D, a vacuum means F is operated, the transfer means 20 of an electrode transfer means C is set in the starting position of corona discharge treatment by means of a control unit E and the surface of the molding 1 is irradiated with corona discharge from the discharge point 52a of said electrode 50 by means of the high-frequency application means B to perform corona discharge treatment.

Description

[Detailed Description of the Invention] Purpose of the Invention (Industrial Field of Application) This invention relates to a corona discharge electrode (hereinafter simply referred to as an electrode).
It is related to the structure of

(Prior Art) Polyolefin resins such as polyethylene and polypropylene have few polar groups, so paints, adhesives, printing agents, etc. are difficult to adhere to their surfaces.

Therefore, in order to modify the surface of resin molded products (hereinafter referred to as molded products) made from polyolefin resins, etc. to make them easier to paint, adhere, or print, it has been known to modify polyolefin films, etc. Application of surface modification methods such as the corona discharge treatment method may be considered.

(Problems to be Solved by the Invention) However, when the corona discharge treatment method was directly applied to the surface treatment method for molded articles, it was found that the following problems occurred.

As shown in FIG. 10, a rod-shaped electrode 100 is used in the corona discharge treatment method, and the distance between this electrode 100 and the surface of the molded product 101 can only be about 3 mm; if the distance is longer than that, Corona discharge does not occur on the surface to be treated of the molded product 101, or even if it occurs, it is weak, so that only a small treatment area can be obtained.

Therefore, the productivity of corona discharge treatment decreases.

Therefore, we had no choice but to carry out corona discharge treatment by bringing the tip of the electrode (*100) as close as possible to the surface of the molded product 101!
! However, if the tip of the electrode 100 is brought too close to the molded product 101, the dimensional accuracy may be up to 5 mm depending on the molded product 101.
Since the electrode 100 also varies, there is a problem that the electrode 100 comes into contact with the surface of the molded article 101 and damages the molded article 101, making it impossible to continue the corona discharge treatment smoothly.

In the present invention, even if contact between the molded product and the electrode due to variations in the dimensional accuracy of the molded product is prevented by increasing the distance between the molded product and the electrode, the productivity of corona discharge treatment does not decrease) rF5 It is intended to provide 12 artificial electrodes.

Five-groove structure of the invention (Means for solving the problems) In order to solve the above-mentioned problems, the present invention is composed of a base and a plurality of branch parts branching from the base and extending substantially parallel to each other. , an electrode configuration is adopted in which a discharge end for corona discharge toward the surface of the object to be treated is formed at the branch portion.

(Function) Since the tips of the plurality of branch parts branching from the base are provided with discharge ends that discharge corona toward the surface of the object to be treated, the distance of corona discharge increases. Therefore, it is possible to increase the distance between the discharge end and the object to be treated.

Since a plurality of branch portions are provided, the productivity of corona discharge treatment can be increased by arranging the branch portions laterally with respect to the direction of relative movement between the electrode and the object to be treated.

(First Embodiment) Next, a first embodiment embodying the present invention will be described based on FIGS. 1 to 6.

As shown in FIG. 1, the electric current 150 of this embodiment is formed from one base 51 and a branch 52 branching from the end of the base 51. As shown in FIG.

The base 51 includes a cylindrical base main body 51a that is connected to a lead wire extending from a high frequency application means to be described later, and a plate-shaped base main body 51a that is joined to the tip of the base main body 51a so as to be perpendicular to the base main body 51a. It is formed from a branch base member 51b.

A plurality of cylindrical branch portions 52 having the same length are planted on the lower surface of the branch base member 51b in parallel with each other and at approximately constant intervals.

Therefore, the discharge end 52a is located approximately on a straight line.

The tip of the branching portion 52 is formed with a conical sharp end 52 that emits a corona discharge toward the surface of the molded product 10 as the object to be processed.
a are arranged so as to be separated from the lower surface of the branch base member 51 by the same distance.

The electrode 50 is made of durable special steel, such as stainless steel.

Next, the molded product and the corona discharge treatment device will be explained.

[Molded product 1] As shown in FIG. 2, molded product 1 is a type of automobile interior part molded from polypropylene resin, and four grooves 2 are formed on the surface to be subjected to corona discharge treatment.

In addition, the length of this molded product is 1200 m.
m, width is 40mm, thickness is 3mm, depth of groove 2 is 0.1
mm, the groove width was 0.4 mm, and variations in dimensional accuracy of up to 5 mm were observed.

After the molded article 1 has been subjected to a corona discharge treatment, a skin made of polyvinyl chloride resin is adhered to its surface.

[Corona discharge treatment device] As shown in FIGS. 3 and 4, a corona discharge treatment device is installed on the base A and at 41110 on the side of the base A in order to cause the electrode 50 to cause corona discharge. a high-frequency applying means B, an electrode moving means C installed on the second stage of the base A for three-dimensionally moving the electrode 50, and an electrode moving means C installed below the electrode 50 and facing it. and a counter electrode means.

In addition, on the side to the base (on the right side in FIG. 3), there are control units 1 to 3 for controlling the electrode moving means C, and on the inner lower part of the base A, a corona discharge treatment is provided. Exhaust means are provided for exhausting gases such as ozone that are generated at times.

The high frequency port 7]0 means B is composed of an oscillator 11 that generates a high frequency, and a high voltage transformer (not shown) that boosts the high frequency generated there and applies a high voltage to the electrode 50. As the oscillator 11, for example, 20 to 30K
H2, a Tantic product (product name 1-IVO5-2) that generates high frequency waves with a maximum output of 350 W, is used, and a Tantic product (product name Super C) is also used as the high voltage transformer.

Electric power (the small moving means C is connected to the X-axis (
An X-axis moving means 20 for moving in the left/right> direction, a Y-axis moving means 30 for moving in the Y-axis (back and forth) direction, also indicated by arrow Y, and a Z-axis (up and down) direction, also indicated by arrow Z. Z to move to! 1g1l moving means 40.

In the axis input moving means 20, two guide rods 28 are fixed on the base A in parallel and horizontal direction.

A turntable 26 for supporting the Y-axis moving means 30 is provided on the guide rod 28 so as to be slidable in the X-axis direction. Note that a threaded portion 29 is provided on the bottom surface of the turntable 26.
A supporting member 23 with a
The two guide irons 28 are inserted through.

Further, one screw shaft 27 is screwed into the threaded portion 29 between the two guide rods 28, and a gear 21 is attached to one end of the screw shaft 27. This gear 21 meshes with the gear 22 of the rotating shaft 24 of the servo motor 25, and the rotation of the servo motor 25 is caused by the rotation of the screw shaft 27.
It is intended to be transmitted to

In this way, the rotation of the servo motor 25 is converted into a displacement of the turntable 26, and the Y-axis moving means 30 is moved in the X-axis direction.

As shown in FIG. 5, two bearings 35 are provided on both sides of the turntable 26 in the Y-axis moving means 30, and two screw shafts 31 are rotatably attached to these bearings 35. It is attached so that it cannot move forward or backward, and both shafts 31 extend parallel to each other and in the horizontal direction. A gear 36 is attached to one end side of each of these screw shafts 31, and these gears 36 mesh with a gear 37 attached to the rotating shaft 3B of the servo motor 32.

The two screws N31 have a threaded member 34 spanning the same axis 31.
are screwed together, and one end of a Y-axis arm 33 extending forward is attached to the center of the screwing member 34. At the other end of the Y-axis arm 33, there is a Z@ moving means 4.
0 is fixed.

In this way, even if J3 is in the Y-axis moving means 30, the rotation of the servo motor 320 is transmitted to the gear 37.36, the screw 10% 31, and the threaded member 34, so that the X-axis moving means 40 moves in the Y-axis direction. It has become.

In the X-axis moving means 40, a plate-shaped fixed table 41 is vertically fixed to the other end of the Y-axis arm 33. Two guide rods 42 are fixed to the front side of the fixed table 41 in parallel and vertically, and a sliding member 44 is slidably attached to both the guide rods 42 so as to straddle them.

A screw splitter 46 extending upward is screwed into a screw (not shown) provided at the center of the sliding member 44, and the screw shaft 46 is connected to a rotating shaft 47 of a servo motor 45 installed on the top of the fixed table 41. Directly connected.

On the other hand, the upper end of a downwardly extending Z-axis arm 43 is fixed to the central part of the sliding vj member 44, and the electric current 1i is fixed to the lower part 41 of the Z-axis arm 43.
5 Q is being grasped. The base end of the base 51 of this electrode 50 is connected to the oscillator 11 via a transformer.

In this way, when the servo motor 45 is rotated, the screw III 146 rotates and the Z
The shaft arm 43 and the electrode 50 move up and down.

In addition, the control unit E includes an 11 control circuit (not shown) using a microcomputer, etc., and the control circuit includes X, Y,
A motion program for controlling the operation of the Z-axis moving means 20, 30, 40 and a program for controlling the start and stop of the operation of the high frequency application means B are written.

[Counter electrode] As shown in FIG. 6, the counter electrode means includes an electrode stand 61 framed on the base A, and an electrode stand 61 formed on the electrode stand 61 so as to match the shape of the back side of the molded product 1. A counter electrode 62 is provided, and the back surface of the molded product 1 is brought into contact with the upper surface of the counter electrode 62.

Next, the functions and effects of this embodiment will be described.

The corona discharge treatment apparatus has a branch base member 51b having a length of 5Qmm and a length up to the sharp end 52a of 6mm.
, an electrode 50 having nine branches 52 each having a diameter of Q and 5 mm was attached.

Next, the molded product 1 is cleaned with a special solvent, set on the counter electrode means, and the back surface of the molded product 1 and the counter electrode 62 are cleaned.
and were brought into contact.

After operating the exhaust means E, turn on the control unit E, and set the X, Y, and Z axis moving means 20, 30, and 40 of the electrode moving means B to the start position of the corona discharge treatment. High frequency application means B was activated. At this time, the distance H between the sharp end 52a of the electrode 50 and the molded product 1 is 10 mm, and the distance H between the electrode 50 and the counter electrode 63 is 28 mm.
A high frequency of KV was applied. Then, the surface of the molded product 10 was irradiated with corona discharge from the sharp end 52a of the electrode 50.

The X, Y, and Z axis moving means 20, 30, 40 are moved by the rotation of a servo motor 25, 32, 45 based on a signal from the control unit E, and the electrode 50 is moved at a rate of 1 to 250 cm/sec near the surface of the molded product 1. moved at a speed of Then, when the electrode 50 was moved back and forth once near the surface of the molded product 1, the surface treatment of the molded product 1 was completed.

In this way, the corona discharge treatment of the molded product 1 is completed in about 50 seconds, which is more noticeable than in the case of similar treatment using the conventional electrode (diameter 2 mm, length 50 mm) shown in Fig. 10. was able to improve productivity.

On the surface of the molded article 1 that has been subjected to the corona discharge treatment, some of the bonds between carbon and hydrogen in the polypropylene molecules are broken, and the molecules are ionized or oxidized and activated.
When a polyvinyl chloride resin skin was bonded to the surface of the material, its adhesion was improved.

With this embodiment, even if the distance between the sharp end 52a of the electrode 50 and the surface of the molded product 1 is separated by a distance greater than the range of variation in the dimensional accuracy of the molded product 1, the productivity of corona discharge treatment can be improved. The results were as follows.

(Second Embodiment) As shown in FIG. 7, eight branch parts 52 are planted substantially parallel to each other at regular intervals on a branch base member 51a of the base 51 of the electrode 50.

However, the electrodes 50 of this embodiment are different from those of the first embodiment in that their lengths are not all the same, only the three on the left are almost the same, and the others are all different.

Furthermore, a spherical curved body 52b is provided at the tip of each branch portion 52. As shown in FIG. 8, the curved body 52b
The lower half of the surface has a pointed portion 5 pointing outward.
2a emits corona discharge.

Therefore, the electrode 50 having this structure is particularly effectively used for a molded product 1 whose surface to be treated is curved or inclined (see FIG. 7). In this case, the counter electrode 62 in the counter electrode means is placed on the molded product 1 on the electrode stand 61.
It is made by forming a metal layer on an electrode base 63 made of epoxy resin or the like that is molded to match the shape of the back surface of the electrode.

In this embodiment, since a plurality of branch parts 52 are provided, not only high productivity can be achieved as in the case of the first embodiment, but also the electrode stand 61 can be used in a curved molded product 1 or in an inclined state.
It is effectively used for the corona discharge treatment of the molded product 1 set in the.

Although the present invention has been described in detail with reference to the above embodiments, the present invention is not limited to these embodiments. For example, as shown in FIG. Branch base members 52b are arranged in the vertical and horizontal directions.
The electrode 50 can also be formed by combining the branch portion 52 and the branch portion 52 in a triangular shape.

In this embodiment, the discharge end 52a is connected to the branch base member 52.
(at a level a certain distance away from b).

Further, the curved body 52b in the second embodiment may be an elliptical body of revolution, and the discharge end 52a may have a simple angular shape instead of a conical sharp end.

Effects of the Invention As detailed above, in the present invention, a plurality of branch parts are branched in parallel at the base of the electrode, and a discharge end for corona discharge is formed at the tip of the branch part. Corona discharge can be performed at a large distance from the surface of the object to be treated. As a result, variations in dimensional accuracy can be absorbed and the workpiece can be subjected to corona discharge treatment with high productivity.

[Brief explanation of drawings]

Figures 1 to 9 are drawings according to the present invention, in which Figure 1 is a perspective view of the first embodiment above the object to be treated, Figure 2 is a perspective view of the object to be treated, and Figure 3 is a corona discharge treatment apparatus. 4 is a partially cutaway side view of the corona discharge treatment device, FIG. 5 is a plan view of the Y-axis moving means, FIG. 6 is a partially longitudinal side view of the electrode stand, and FIG. 7 is a partially cutaway side view of the corona discharge treatment device. FIG. 8 is a side view of the second embodiment, FIG. 8 is an enlarged view of the section 5, FIG. FIG. 2 is a perspective view of the technique. Base portion 51, branch portion 52, discharge end 52a, curved body 2b Patent applicant Toyoda Gosei Co., Ltd. Figure 2 Figure 6 Figure 3

Claims (1)

[Claims] 1. Consisting of a base (51) and a plurality of branch parts (52) that branch from the base (51) and extend substantially parallel to each other, and at the tip of the branch part (52). An electrode for corona discharge, characterized in that it is provided with a discharge end (52a) that discharges corona toward the surface of the object to be treated (1). 2. The corona discharge electrode according to claim 1, wherein the discharge ends (52a) are aligned substantially in a straight line or flush. 3. The corona discharge electrode according to claim 1, wherein the discharge end (52a) is a pointed end. 4. The corona discharge electrode according to claim 1, wherein the branch portions (52) are aligned so as to be substantially flush with each other, and the discharge end (52a) is a sharp point. 5. The branch part (52) has a curved body (52b) at its tip.
), and the curved body (52b) is provided with a discharge end (52a). 6. The corona discharge electrode according to claim 5, wherein the discharge end (52a) is a pointed end.