JPS62174234A - Counter electrode for corona discharge treatment - Google Patents

Abstract

PURPOSE:To obtain the title counter electrode which can generate a corona discharge uniformly and exactly, by disposing a counter electrode fitted with a means for close adhesion of a molding to be subjected to corona discharge treatment on the back of the molding. CONSTITUTION:An electrode base 62 of a shape coinciding with the three- dimensional shape of the back of a molding 1 to be subjected to corona discharge treatment is supported on the top of a hollow electrode mount 61 placed on a bse. A thin film electroconductive layer 63 is formed as a coating on the surface of that part of the base 62 which coincides with the back of the molding 1 to form a counter electrode 60 consisting of the base 62 and the electroconductive layer 63. A suction pipe 65 communicating with the main suction pipe 64 formed in the inside of the electrode mount 61 is buried in the inside of the part coinciding with the back of the molding 1, an vacuum holes 67 communicating with the surface of the electroconductive layer 63 are formed in the suction pipe 65 at predetermined intervals.

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) This invention relates to a counter electrode used in corona discharge treatment of resin molded articles.

(Prior Art) Since polyolefin resins such as polypropylene have few polar groups, they have the characteristic that paints, adhesives, printing, etc. are difficult to adhere to their surfaces. Therefore, paint on the surface of the resin,
When performing adhesion, printing, etc., it is necessary to perform a modification treatment on the surface as a pretreatment to improve the adhesion.

Conventionally, flame treatment (flame treatment) and acid solution treatment using dichromic acid solution have been used as modification treatments for three-dimensional resin molded products made of polyolefin resin, but recently plasma treatment has also been used. It started to be done. The plasma treatment can activate almost the entire surface of the resin molded product at once, so it can be used for automobile bumpers,
It has achieved great results in pre-treatment for painting and adhesion of moldings, etc.

(Problems to be Solved by the Invention) However, since the plasma processing requires a reduced pressure plasma gas atmosphere, it requires costly and expensive equipment such as a vacuum chamber, vacuum pump, valve device, and carrier gas. However, there is a problem in that it takes time to reduce the pressure inside the vacuum chamber. In addition, since the process inevitably requires batch processing, it is difficult to automate the process, and there is also the problem that the vacuum is broken after each process and it takes time for the next depressurization.

Therefore, the present inventors have focused on corona discharge treatment performed as a modification treatment for resin films, but there are many difficulties in adopting this treatment method for modification treatment of three-dimensional resin molded products. One of them is that when molded products have various three-dimensional shapes, conventional roll-shaped or flat-shaped counter electrodes create a large air space between them and the resin, and the discharge electrode The problem is that corona discharge no longer occurs because the distance between the two becomes large.

Therefore, it has been considered to narrow the gap between the counter electrode and the discharge electrode by forming the counter electrode in almost the same shape as the back surface of the three-dimensional resin molded product. A resin mold having the same shape as the back surface of the resin molded product is formed, and a thin conductive layer is coated on this surface to form a counter electrode.

However, even when this method is used, the following problems may occur.

That is, the resin molded product is warped or bent due to heat shrinkage after molding, and the molded product is deformed. The manner in which this deformation occurs varies depending on each molded product, and when a plurality of molded products are compared, the manner in which this deformation occurs is not uniform as a whole, and variations occur. Therefore, depending on the molded product,
There may be a portion where the back surface and the counter electrode do not come into close contact with each other, and a gap may be created between the two to serve as an insulating layer.

When the number of gaps becomes 511 or more, the discharge output of corona discharge decreases, and the modified area of the discharge electrode decreases.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention is arranged on the back side of the surface to be treated of a molded article for corona discharge treatment, and connected to a discharge electrode through the molded article. A means is employed in which the opposing electrodes are provided with molded article contact means for bringing the molded article for corona discharge treatment into close contact with the opposed electrodes, at least in part thereof.

(Function) The molded product adhesion means provided on the counter electrode ensures that the entire back surface of the molded product placed on one surface of the counter electrode is firmly attached to the surface of the counter electrode, regardless of deformation of the individual molded products. Closely attached. Therefore, no gap is generated between the back surface of the molded product and the counter electrode, and it is possible to prevent a decrease in the discharge output of the corona discharge treatment and a decrease in the modified area due to the gap.

(First Embodiment) A first embodiment embodying the present invention will be described below with reference to FIGS. 1 to 7.

First, the molded product to be subjected to corona discharge treatment in this example is an automobile instrument panel pad (hereinafter abbreviated as instrument panel pad) 1 as shown in FIGS. The instrument panel is constructed by adhering a skin sheet made of (vinyl chloride) resin.

The instrument panel pad l has a boundary between its top surface 2 and front surface 3;
It has a convex corner portion 5 at the boundary between the top surface 2 and the side surface 4, etc.

Furthermore, two shallow dish portions 6.7 are provided on both left and right sides of the upper surface 2 of the instrument panel pad. Therefore, as shown in FIG. 2, concave corner portions 9 are present at the bottom edges of the dish portions 6 and 7, respectively.

Next, a device for subjecting the instrument panel pad 1 to corona discharge treatment will be described.

This corona discharge treatment device is mounted on a base 80 formed of two stages, front and back, with a metal frame, and the device can be divided into two parts: A: instrument panel pad 1 is fixed, and a counter electrode is contacted to the back surface of the instrument panel pad 1; In order to do this, the first stage of the base 80 has a counter electrode means A grounded, and B: a corona discharge treatment and a moving means for three-dimensionally moving this. Discharge electrode means B arranged on the second stage; C: High frequency application means C arranged on the shelf 14 on the left side of the base 80 for applying high frequency between the electrodes; D= Electrode moving means B The control unit D is grounded on the right side of the base 80 in order to control the operation.

Hereinafter, the details of each part A to D will be explained in order.

[Counter electrode means A]

1st. 2. 4. As shown in FIG. 5, a hollow electrode stand 61 is installed on the first stage of the base 80, and the upper part of the electrode stand 61 is made of epoxy resin to form a three-dimensional shape on the back surface of the instrument panel pad 1. An electrode base material 62 formed in a matching shape is supported to support the instrument panel pad 1 from the back surface. This electrode base material 62 is formed by pouring an epoxy resin onto the back surface of the instrument panel pad 1 and curing it by reaction.

A thin conductive layer 63 is coated on the surface of the electrode base material 62 at a portion corresponding to the back surface of the instrument panel pad 1 by metal plating, and the electrode base material 62 and the conductive layer 63 are opposite to each other. An electrode 60 is configured.

As shown in FIG. 1, an intake pipe that communicates with an intake main pipe 64 formed inside the electrode base 61 is provided inside a portion of the electrode base material 62 that corresponds to the back surface of the instrument panel pad 1. 65 is bent into a shape that matches the external shape of the instrument panel pad 1 and embedded therein. A plurality of the intake pipes 65 are embedded at predetermined intervals in the longitudinal direction (left and right in FIG. 4) of the electrode base material 62, and each intake pipe 6
A vacuum hole 67 communicating with the surface of the conductive layer 63 is formed in the conductive layer 5 . The vacuum holes 67 are formed at predetermined intervals in the intake pipe 65, and are particularly formed in large numbers in portions corresponding to the corner portions 5, 8.9 of the instrument panel pad 1.

Further, the suction main pipe 64 formed in the electrode stand 61 has its base end connected to a vacuum suction device (not shown).
When the vacuum suction device is operated, vacuum suction is performed through the vacuum hole 67 that communicates with the intake pipe 65.

As mentioned above, the counter electrode 60 of this embodiment is not only formed to have the same shape as the back surface of the three-dimensional resin molded product, but also the entire back surface of the instrument panel pad 1 is attached to the surface of the counter electrode 60 by the molded product adhering means described above. It is formed so that it can be forcefully brought into close contact. Therefore, this counter electrode 6
0 allows the entire back surface of the instrument panel pad 1 to be brought into close contact with the counter electrode 60 regardless of deformation of each molded product during molding of the instrument panel pad 1.

[Discharge electrode means B]

As shown in FIGS. 4 to 6, the discharge electrode means B includes a corona discharge electrode 50, an X-axis moving means 20 for moving this in the X-axis (left and right) direction, and a Y-axis means (front and rear). Y-axis moving means for moving and also Z-axis (up and down)
It is composed of a two-axis moving means 40 for moving in the direction.

In the X-axis moving means 20, two guide rods 28 extending in parallel in the horizontal direction are attached to the base 80. A turntable 26 for supporting the next Y-axis moving means 30 is provided on the guide rod 28 so as to be slidable in the X-axis direction. That is, a support member 23 is attached to the lower surface of the turntable 26, and both guide rods 28 are inserted through the support member 23, so that the turntable 26 can be slid.

Further, the support member 23 on the lower surface of the turntable 26
A screw portion 29 is attached to the left and right sides of the screw portion 29, and one screw shaft 27 is screwed into and retractably from the screw portion 29. A gear 21a is attached to the right end of the screw shaft 27, and the gear 21a meshes with a gear 21b of a servo motor 25 attached to the right end of the base 80.

Therefore, when the servo motor 25 rotates, the gear 213 .
Since the screw shaft 27 rotates via the screw shaft 21ba, the turntable 26 moves in the X-axis direction together with the threaded portion 29 screwed onto the screw shaft 27.

Next, in the Y-axis moving means 30, the turntable 2'
Two bearings 35 are provided on each side of the upper surface of the bearing 6. Two screw shafts 31 are rotatably but immovably attached between the left and right bearings 35, and both shafts 31 extend in parallel in the horizontal direction.

A gear 36a is attached to the front and rear of each screw shaft 31,
Each gear 36a is meshed with a gear 36b of a servo motor 32 attached to the rear end of the base 80.

A threaded member 34 spanning both shafts 31 is threaded onto the two screw shafts 31, and a Y-axis arm 33 extending forward is attached to the center of the threaded member 34. Y
The next Z-axis moving means 40 is fixed to the front end of the shaft arm 33.

Therefore, also in the Y-axis moving means 30, the servo motor 32
The rotation of the gear 36, screw shaft 31 and threaded member 34
The Z-axis moving means 40 is moved in the Y-axis direction.

Next, in the Z-axis moving means 40, a fixed table 41 is fixed to the front end of the Y-axis arm 33 so as to stand vertically. Two guide rods 42 are provided at the front end of the fixed table 41.
are fixed, and both rods 42 extend in parallel in the vertical direction.

A sliding member 44 that spans both guide rods 42 is slidably attached thereto, and a female thread (not shown) is formed in the center of the sliding member 44 . A screw shaft 46 extending upward is screwed into the female thread, and the screw shaft 46 is directly connected to a rotation shaft 47 of a servo motor 45 attached to the upper part of the fixed table 41.

On the other hand, a downwardly extending Z-axis arm 43 is fixed at its upper end to the center of the sliding member 44.
A discharge electrode 50 for corona discharge is always held in a substantially vertical position at the lower end of the discharge electrode 3 .

Therefore, when the servo motor 45 is rotated, the screw shaft 46 rotates and the Z-axis arm 43 is rotated via the sliding member 44.
And the discharge electrode 50 is moved up and down.

The discharge electrode 50 placed in the atmosphere includes a gripped part 51 made of stainless steel and having a diameter of about 211 mm, and a gripped part 51 made of stainless steel and attached to the tip of the gripped part 51 with a diameter of about 6 mm. It consists of a spherical discharge tip 52. As described above, the gripped part 51 is gripped by the Z-axis arm 43 in a substantially vertical state at all times, and each of the moving means 20, 30, 40
It is designed so that it does not tilt even when it is moved.

As shown in FIG. 7, it is desirable to provide a mesh-shaped shield cylinder 53 made of stainless steel or the like around the discharge electrode 50. This is because the shield tube 53 can prevent radiation of high frequency noise during corona discharge.

[High frequency application means C]

As shown in FIG. 4.7, the conductive layer 63 and the discharge electrode 5
0 is connected to high frequency application means C consisting of a high frequency oscillator 16 and a sound pressure transformer 17, and the conductive layer 63 is grounded. Further, as a countermeasure against high frequency noise, the high frequency oscillator 16 is also directly grounded.

High frequency oscillator 16 has 20~30KH2, maximum output 35
Tantic's product (product name H) that generates 0W high frequency
VO5-2) is used.

The high voltage transformer 17 is for boosting the high frequency output of the high frequency oscillator 16 and applying a high voltage between the conductive layer 63 and the discharge electrode 50.
The product name Spar C) is used.

[Control unit D]

A control circuit (not shown) using a computer or the like is incorporated in the control unit D, and the control circuit includes X, Y, and Z axes in order to move the discharge electrode 50 near the surface of the instrument panel pad L. A motion program for controlling the operation of the moving means 20.degree. 30.40, a program for controlling the start and stop of the operation of the high frequency application means C, etc. are written therein.

This control unit D and the high frequency application means C are arranged at a considerable distance with the base 80 in between, and are powered separately and independently.

This is to prevent the computer of the control unit D from malfunctioning due to high frequency noise leaking from the high frequency applying means C. Furthermore, for the same reason, the cord connecting the high frequency oscillator 16, high voltage transformer 17 and discharge electrode 50 must be reliably shielded.

As shown in FIG. 5, an exhaust means E for exhausting gas such as ozone generated during the corona discharge treatment is disposed at a position behind the counter electrode means A on the base 80. ing.

Now, a method for corona discharge treatment of the instrument panel pad 1 using the corona discharge treatment apparatus configured as described above will be described.

First, if molded instrument panel pad 1 has dirt, etc. caused by a mold release agent or manual labor attached to it, it is desirable to perform a pretreatment to clean the dirt with an organic solvent such as trichloroethane. This is to ensure that corona discharge treatment is performed.

However, if there is no mold release agent or dirt, or if it is only slight, there is no need to perform pretreatment.

Next, as shown in FIGS. 1.2 and 4.5, the instrument panel pad 1 is placed on the counter electrode 60 of the counter electrode means A. At this time, if the vacuum suction device is operated to draw suction from the vacuum hole 67 on the surface of the conductive layer 63, the suction force will forcibly attract the back surface of the instrument panel pad 1 to the counter electrode 60, and the counter electrode 50 surface and is firmly adhered to the surface.

Therefore, all parts of the conductive layer 63 of the counter electrode 60 and the back surface of the instrument panel pad 1 can be brought into close contact with each other irrespective of deformation such as warping or bending of the instrument panel pad 1.

Therefore, almost the entirety of the instrument panel pad 1 formed of dielectric PP resin is electrically and effectively coupled to the Hiden Ji 63, and the distance between the conductive layer 63 and the discharge electrode 50 can be kept small. It becomes possible. As a result, the discharge electrode 5
Corona discharge is likely to occur from zero.

Now, hypothetically, the interior of the instrument panel pad 1 and the counter electrode 60
If there is no close contact with the surface and an air layer is formed between them, this air layer acts as an insulating layer, making it difficult for corona discharge to occur and reducing the corona discharge output and modification range. In this embodiment, this air layer is eliminated by the vacuum suction to achieve the electrical connection.

Next, after operating the exhaust means E, the control unit I-D is turned on, and the moving means 20, 30, 40 of each axis in the discharge electrode means B are set to the start position of the corona discharge treatment. At this time, (1) the gripped portion 51 of the discharge electrode 50 is always supported vertically, and (2) the discharge tip 52 is located about 1 inch above the left end of the front edge of the instrument panel I.
They are located at intervals of 0fi■.

Then, when the high frequency oscillator 16 of the high frequency applying means C is activated, its high frequency output is boosted by the high voltage transformer 17, and a high frequency of 28 KV is applied between the conductive layer 63 and the discharge electrode 50. Then, corona discharge occurs in the atmosphere between the portion of the discharge tip 52 facing the upper surface 2 and the upper surface 2, and corona discharge treatment of the upper surface 2 is started.

The X, Y, and Z axis moving means 20.30.40 are moved in each direction by the rotation of a servo motor 25.32.45 operated based on a control signal from the control unit ID,
The discharge electrode 50 moves near the surface of the instrument panel pad l.

Note that the moving speed of the discharge electrode 50 can be arbitrarily set within the range of 1 to 250 sec/sec under the discharge conditions, but in this example, sufficient corona discharge treatment effect and treatment time can be set. Considering the shortening of 15.
On■/sec.

The entire surface of the instrument panel pad 1 is subjected to the corona discharge treatment with the above-described reciprocating movement, thereby improving the adhesion of adhesives and the like. The improvement in wettability due to the corona discharge treatment in this example is similar to that achieved by conventional flame treatment (flame treatment).
It is about the same.

In addition, since the corona discharge spreads from the discharge tip 52 in an extremely uniform discharge pattern as shown in FIG. fully processed.

As described above, the counter electrode 60 of this embodiment has a contact means formed so that its back surface always comes into close contact with the front surface of the counter electrode 60 regardless of various deformations and shapes of the instrument panel pad 1. There is no gap between the back surface of the instrument panel pad 1 and the surface of the counter electrode 60, and a reliable corona discharge can be generated.

Further, this embodiment is effective because many of the vacuum holes 67 are provided in the portions facing the corner portions 5, 8, and 9 where voids are generally likely to be formed.

Furthermore, since the entire back surface of the instrument panel pad l is in close contact with the counter electrode 60, it is possible to prevent unevenness in the modified state due to partially generated voids.

Moreover, according to the corona discharge treatment apparatus of this embodiment, not only can the equipment cost and equipment space be significantly reduced compared to conventional plasma processing, but also the processing time can be shortened.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. This embodiment differs from the first embodiment only in that the pressure is changed to .

That is, as shown in FIG. 8, the instrument panel pad 1
A rod-shaped press rod 71 is arranged at the upper and lower ends of the instrument panel pad 1 in a shape that matches the product shape of the instrument panel pad 1 so as not to widen the distance between the discharge electrode 50 and the molded product. The fixing hole 7 formed in the electrode base material 62 is inserted into the fixing hole 7 formed in the electrode base material 62.
3, the instrument panel pad 1 is fixed in a pressed state toward the counter electrode 60 side.

Therefore, this embodiment also exhibits the same effects as the first embodiment, and does not require relatively expensive equipment such as a vacuum device, so it can be implemented in a conventional corona discharge treatment device at low cost. I can do it.

Note that the present invention is not limited to the above embodiments,
For example, it is also possible to implement the following modifications.

(1) The means for adhering the molded product formed on the counter electrode 60 is not limited to the vacuum suction or the pressing member 70 of each of the above embodiments, but any means that can bring the molded product into close contact with the counter electrode 60 can be used. Any method may be used, and for example, double-sided adhesive tape may be attached to the surface of the counter electrode 60 to serve as the means for adhering the molded product.

(2) The structure of the X, Y, and Z axis moving means 20, 30, and 40 in the discharge electrode means B may be changed, or an articulated robot or the like may be used instead. Further, a three-dimensional movement mechanism may be provided in the counter electrode means B to move the instrument panel pad 1 to bring it closer to the discharge electrode 50.

(3) In addition to the instrument panel pad 1, the present invention can be used as a counter electrode for all three-dimensional resin molded products that require painting, adhesion, printing, etc. after molding, such as automobile bumpers, automobile moldings, etc. In addition, it can also be used as a counter electrode for a two-dimensional resin molded product.

Effects of the Invention As detailed above, the counter electrode for corona discharge treatment of the present invention is equipped with a molded article adhesion means for forcibly bringing the molded article to be subjected to corona discharge treatment into close contact with the surface of the counter electrode. Even if the individual molded products are deformed, they can be pressed and brought into close contact, and it is possible to prevent gaps from forming between the molded products and the counter electrode, which would reduce the corona discharge output and the modified area. This results in an excellent effect in that uniform and reliable corona discharge can be generated.

[Brief explanation of drawings]

1 to 7 show a first embodiment embodying the present invention, FIG. 1 is a sectional view showing the instrument panel pad and counter electrode means cut back and forth, and FIG. 2 is a cross-sectional view showing the instrument panel pad and counter electrode means cut sideways. 3 is a perspective view of the instrument panel pad, 4 is a front view of the corona discharge treatment device, 5 is a right side view, and 6 is a sectional view.
The figure is a plan view of the Y-axis moving means, FIG. 7 is a schematic diagram showing the connection between the discharge electrode and the high frequency application means, and FIG. 8 shows the second embodiment, in which the instrument panel pad and the counter electrode means are cut back and forth. FIG. Molded product for corona discharge treatment...l Discharge electrode...50 Counter electrode...60 Patent applicant Toyoda Gosei Co., Ltd. Agent
Patent Attorney On 1) Hironobu Figure 8

Claims (1)

[Claims] 1. A counter electrode (60) disposed on the back side of the surface to be treated of the molded article (1) for corona discharge treatment and facing the discharge electrode (50) through the molded article (1). A counter electrode for corona discharge treatment, characterized in that at least a part of the molded article (1) is provided with molded article adhesion means for bringing the molded article (1) into close contact with the counter electrode (60). electrode. 2. The molded product adhering means is for molded products for corona discharge treatment (1
), wherein a plurality of vacuum holes (67) are provided through the surface of the counter electrode (60). Counter electrode for corona discharge treatment. 3. The molded product adhering means is bolted (72) to the end of the counter electrode (60), and the molded product for corona discharge treatment (
1) is a pressing rod (71) made of an insulator so as to press the counter electrode (60) against the counter electrode (60). .