JPS62178322A - Counter electrode for corona discharge treatment - Google Patents

Abstract

PURPOSE:To prevent a void from generating among a molded article and counter electrodes, by forming at least parts of the counter electrodes with which the backside of a molded article comes into contact are formed of a deformable material. CONSTITUTION:At least a part of an electrode with which the backside of a molded article 1 comes into contact is formed of a deformable material, in the counter electrodes 60 arranged on the backside of the surface to be treated of the material 1 for corona discharge treatment and opposed to a discharge electrode 50 through the molded article 1. The deformable material is sponge or synthetic rubber made of polyester resin. As the part where the molded article 1 for corona discharge treatment of the counter electrodes 60 is arranged is formed of the deformable material, when the molded article 1 is arranged on that part, a deformation is generated on the counter electrodes 60 through empty weight of the molded article 1 and follows after a form of the backside of the molded article 1. Therefore, the molded article 1 for the corona discharge treatment and the counter electrodes 60 are stuck to each other reliably irrespective of various deformations of the each individual molded article.

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 large-scale and expensive equipment such as a vacuum chamber, a vacuum pump, a valve device, and a 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 the surface thereof 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 this gap becomes large, 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 adopts a means in which at least the part of the counter electrode that contacts the back surface of the molded product is made of a deformable material. are doing.

(Function) The part of the counter electrode where the molded product for corona discharge treatment is placed is made of a deformable material, so when the molded product is placed in that part, the counter electrode will be deformed by the weight of the molded product. It is deformed and follows the shape of the back surface of the molded product. For this reason, the molded article for corona discharge treatment and the counter electrode are firmly attached to each other regardless of various deformations of the molded article.

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

First, to briefly explain the molded product subjected to the corona discharge treatment in this example, this molded product is a three-dimensional resin molded product having three-dimensional irregularities. Furthermore, the resin referred to here particularly refers to a synthetic resin that is a dielectric material.

As shown in Figures 1 to 3, this is an automobile instrument panel pad (hereinafter referred to as an instrument panel pad) made of PP resin, which is a dielectric material, and the surface of which is made of PVC (polyvinyl chloride). The instrument panel is constructed by bonding resin skin sheets.

The instrument panel pad 1 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.

Further, two shallow dish portions 6 and 7 are provided on both left and right sides of the upper surface 2 of the instrument panel pad. Accordingly, as shown in FIG. 2, a concave corner 9 is present at the bottom edge of each pan 6.7.

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 a gold mud frame in two stages, front and back, and the device is 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 of the sections A to D will be explained in order.

[Counter electrode means A]

As shown in FIGS. 1.2 and 4.5, a hollow electrode stand 61 is installed on the first stage of the base 80.

An electrode base material 62 is fixed to the upper part of the electrode base 61, which is made of a sponge made of polyester resin, which is an elastically deformable material, and formed to match the three-dimensional shape of the back surface of the instrument panel pad 1. 1 is supported from the back side.

This electrode base material 62 is formed by pouring molten polyester resin mixed with a foaming material onto the back surface of the instrument panel pad 1 and causing it to react and harden.

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 a gold plating method. An electrode 60 is configured.

In this embodiment, the polyester resin sponge is foamed to about 5 times to 10 times, and the total thickness is about 5 am, which is about twice the thickness of the instrument panel pad L. has been done. Further, the conductive layer 6
For No. 3, Hastelloy

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 is entirely made of an elastically deformable material, so that the instrument panel pad 1 is When placed, it easily undergoes elastic deformation due to its own weight and follows the shape of the molded product, and returns to its original shape when the instrument panel pad 1 is removed. Therefore, this counter electrode 60 can bring the entire back surface of the instrument panel pad 1 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)
and X-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 X-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 slide.

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 21a,
Since the screw shaft 27 rotates via the screw shaft 21b, the turntable 26 moves in the X-axis direction together with the threaded portion 29 screwed onto the screw shaft 27.

Next, in the X-axis moving means 30, the turntable 26
Two bearings 35 are provided on each side of the top surface. 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 having a diameter of about 211 mm and made of stainless steel, and a gripped part 51 having a diameter of about 611 m attached to the tip of the gripped part 51 also made of stainless steel. 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, 30.4
0 so that it does not tilt even when 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 a high frequency applying means C consisting of a high frequency oscillator 16 and a high voltage 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
Tante Risha'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 electrodes 63 and 50.
) 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 a discharge electrode 5.
x to move 0 near the surface of instrument panel pad 1
, y, and z-axis moving means 20°30.40, a program for controlling the start and stop of 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 l using the corona discharge treatment apparatus configured as described above will be described.

First, if the molded instrument panel pad l has dirt, etc. caused by a mold release agent or manual work attached to it, it is desirable to perform a pretreatment of cleaning 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 the dirt is slight, there is no need to perform pretreatment.

Next, the first. 2. 4. As shown in FIG. 5, the instrument panel pad 1 is placed on the counter electrode 60 of the counter electrode means A. At this time, since the counter electrode 60 is entirely formed of a sponge made of polyester resin, which is an elastically deformable material, the instrument panel pad 1 sinks into the counter electrode 60 due to its own weight, and the whole is brought into contact with the counter electrode 60.

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 conductive layer 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 50
corona discharge is likely to occur.

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 elastic deformation of the counter electrode 60 itself, and the electrical coupling is realized.

Next, after operating the exhaust means E, the control unit 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 approximately 10 mm above the left end of the front edge of the instrument panel pad 1.
Located at fin intervals.

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 28 KVO high frequency 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 the respective directions by the rotation of servo motors 25, 32.45 that operate based on control signals from the control unit)D, and the discharge electrode 50 is moved in the respective directions. It moves near the surface of the pad 1.

Note that the moving speed of the discharge electrode 50 can be arbitrarily set within the range of 1 to 250 dragons/sec under the discharge conditions, but in this example, sufficient corona discharge treatment effect and treatment time are required. Considering the shortening of 150
m1+/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.

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

As described above, since the counter electrode 60 of this embodiment is entirely formed of a sponge made of polyester resin as an elastically deformable material, the instrument panel pad l placed on the counter electrode 60 sinks due to its own weight. The entire back surface can be brought into contact with the counter electrode 60. Therefore, even if the instrument panel pad 1 is deformed in various ways, the counter electrode 60
can follow the deformation, so no gap is created between the back surface of the instrument panel pad l and the surface of the counter electrode 60, and a reliable corona discharge can be generated. This counter electrode 60 is connected to the instrument panel pad 1.
When removed, it returns to its original shape, so even if another instrument panel pad 1 with a different deformed portion is placed, the entire back surface of the molded product can be brought into close contact with the counter electrode 60 in the same way.

Furthermore, since the entire counter electrode 60 is formed in advance to have the same shape as the back surface of the instrument panel pad 1,
Followability in individual deformations can be further improved.

Further, since the conductive layer 63 is formed into a thin film, the counter electrode 6
The elastic deformation of the whole 0 is not affected.

Furthermore, since the entire back surface of the instrument panel pad I 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 it includes the following.

That is, as shown in FIG. 8, the electrode base 61 has a hollow thin electrode base material 7 made of synthetic or natural rubber.
1 is placed in a fixed position, and sodium chloride as an electrolytic solution 72 is placed inside it.

Furthermore, by attaching an electrode to the electrolytic solution 72,
The electrolytic solution 72 is used as the conductive layer in the first embodiment.

Therefore, this example also exhibits the same effect as the first example, and since it is not necessary to match the shape of the back surface of the molded product to be subjected to corona discharge treatment in advance, it can be used as a general-purpose counter electrode for corona discharge treatment. .

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

(1) As the elastically deformable material used for the counter electrode 60, in addition to the polyester resin sponge of this embodiment, a sponge made of urethane resin, polyethylene resin, etc. may be used, or a foamed material may be used. Synthetic rubber or a mixture of both may be used.

(2) The metal used for the conductive layer 63 may be a highly conductive metal such as copper, silver, or gold, in addition to the Hastelloy X of this embodiment.

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

(4) In addition to the instrument panel pad 1, the present invention can also be applied to automobile bumpers, automobile moldings, motorcycle mudguard fenders, various industrial equipment, household goods, etc., which require painting, adhesion, printing, etc. after molding. It can be used as a counter electrode for all three-dimensional resin molded products, and can also be used as a counter electrode for two-dimensional resin molded products.

Effects of the Invention As detailed above, the counter electrode for corona discharge treatment of the present invention is made of a deformable material, so even if the molded product undergoes various deformations, it will deform to follow the deformation. However, it is possible to prevent a gap from forming between the molded product and the counter electrode. Therefore, it is possible to prevent a decrease in the corona discharge output and the reformed area caused by the voids, and as a result, it is possible to produce a uniform and reliable corona discharge, which is an excellent effect.

[Brief explanation of drawings]

1 to 7 show a first embodiment embodying the present invention, FIG. 1 is a cross-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...1 Discharge electrode...50 Counter electrode...60 Patent applicant Toyoda Gosei Co., Ltd. Agent
Patent Attorney On 1) Hiroki Figure 1 Drawing Part 1 Figure 8 Drawing Part 3 Figure 8 Drawing Part 6 Figure 6 Drawing Part 1

Claims (1)

[Claims] 1. A discharge electrode (50) is placed on the back side of the surface to be treated of the molded product (1) for corona discharge treatment, and is connected to the discharge electrode (50) through the molded product (1).
A counter electrode for corona discharge treatment, characterized in that, in the counter electrode (60) facing the molded article (1), at least a portion in contact with the back surface of the molded article (1) is formed of a deformable material. 2. The counter electrode for corona discharge treatment according to claim 1, wherein the deformable material is a polyester resin sponge or synthetic rubber.