JPH0313255B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing 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 property that paints, adhesives, printing, etc. are difficult to adhere to their surfaces. Therefore,
When applying paint, adhesion, printing, etc. to the surface of the resin, 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. Since the plasma treatment can activate almost the entire surface of a resin molded product at once, it has achieved great results in pre-painting and adhesion treatment of automobile bumpers, moldings, etc.

However, since the plasma processing requires a plasma gas atmosphere under reduced pressure, it requires large-scale and expensive equipment such as a vacuum chamber, vacuum pump, valve device, carrier gas, etc., and it takes time to reduce the pressure inside the vacuum chamber. There was a problem that it took a while. Furthermore, 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
When molded products have various three-dimensional shapes, conventional roll-shaped or flat counter electrodes create a large air space between them and the resin, and the distance between them and the discharge electrode increases. Therefore, the problem is that no corona discharge occurs.

Therefore, it has been considered to form the counter electrode in almost the same shape as the back surface of the three-dimensional resin molded product. The counter electrode is formed by forming a material and coating the surface with a thin conductive layer.

(Problems to be Solved by the Invention) However, when a three-dimensional resin molded product is placed on the counter electrode formed by the above method, the following problems may occur.

That is, when the three-dimensional resin molded product is provided with a penetrating portion such as a through hole or a notch, the conductive layer is exposed from that portion to the discharge electrode side. Therefore, if a discharge electrode undergoing corona discharge is located on the penetrating portion, the corona discharge may be disturbed and sufficient corona discharge treatment may not be performed. For this reason, it is necessary to provide a dielectric buffer plate at a portion opposite to the penetrating portion of the counter electrode, which requires an extra manufacturing process.

Structure of the Invention (Means for Solving the Problems) Therefore, in order to solve the above-mentioned problems, the method for manufacturing a counter electrode of the present invention provides a method for manufacturing a three-dimensional molded product that has a surface to be subjected to corona discharge treatment. a step of forming a front-side electrode base material by filling a molten resin into the surface, a step of providing a conductive layer on the front-side electrode base material, a step of forming a back-side electrode base material by filling a molten resin onto the conductive layer. The method consists of a step of forming, and a step of removing the front-side electrode base material, the conductive layer, and the back-side electrode base material from the molded product.

(Function) The method for manufacturing a counter electrode of the present invention comprises an electrode base material formed by transfer to be the same or substantially the same as the back surface of the molded product for corona discharge treatment itself, and a conductive layer formed inside the electrode base material. Therefore, a counter electrode can be obtained in which the entire surface of the counter electrode can be reliably brought into contact with the entire back surface of the molded product.

(Example) Hereinafter, an example embodying the present invention will be described with reference to the drawings.

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, the three-dimensional resin molded product subjected to corona discharge treatment in this example is an automobile instrument panel pad (hereinafter referred to as an instrument panel pad) made of PP resin as a dielectric material. (abbreviated as ) 1, and an instrument panel is constructed by adhering a skin sheet made of PVC (polyvinyl chloride) resin to the surface thereof.

The instrument panel pad 1 has a convex corner portion 5 at the boundary between the top surface 2 and the front surface 3, the boundary between the top surface 2 and the side surface 4, and the like.

In addition, there are 2
Two shallow pans 6, 7 are provided. Therefore,
As shown in FIG. 2, concave corner portions 9 are present at the bottom edges of the dish portions 6 and 7, respectively. In addition, a side defroster air outlet 10 is provided at the left end of the upper surface 2.
However, two ventilation/air conditioning air outlets 11 and 12 are formed on the left and right sides of the front surface 3, respectively. Each outlet 10, 11, 12 has a substantially square shape, and rounded corner portions 13 are formed at the edges and four corners.

As mentioned above, the instrument panel pad 1 is a three-dimensional resin molded product, and has many corner parts 5, 8,
It is characterized by having numbers 9 and 13.

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

This corona discharge treatment device is placed on a base 80 formed of two stages, front and back, made of a metal frame, and the device can be divided into two parts: A: An instrument panel pad 1 is fixed, and a counter electrode is attached to the back surface of the base 80. A counter electrode means A is grounded to the first stage of the base 80 in order to make contact with the base 80. Discharge treatment 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 In order to control the base 80
The control unit D is grounded on the right side of the control unit D.

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, 4, and 5, a hollow electrode stand 61 is arranged on the first stage of the base 80, and an instrument panel pad is placed above the electrode stand 61. A counter electrode 62 formed to match the three-dimensional shape of the interior of the instrument panel pad 1 is provided to support the instrument panel pad 1 from the inside.

This counter electrode 62 is composed of an epoxy resin electrode base material 63 formed in the same three-dimensional shape as the back surface of the instrument panel pad 1, and a thin film-like conductive layer 64 formed inside the electrode base material 63.

Therefore, even if the instrument panel pad 1 is placed on the counter electrode 62, the air outlets 10, 11,
The conductive layer 64 from 12 is not exposed to the discharge electrode 50 side. Therefore, the discharge electrode 5 during corona discharge
Even when the corona discharge is located above the air outlet 10, 11, 12, the corona discharge is not disturbed, and furthermore, the corona discharge goes around to the back side of the air outlet 10, 11, 12 and is subjected to corona discharge treatment. It is becoming more and more like this.

The method for manufacturing the counter electrode 62 will be explained in detail.

In order to accurately transfer the shape of the back surface of the instrument panel pad 1, this counter electrode 62 is formed by filling the back surface with molten epoxy resin to a thickness of approximately 5 mm to form a front electrode base material 101, and then forming the front electrode base material 101. A conductive layer 6 is formed by spraying paint (dotite) containing silver powder as a conductor onto the base material 101.
4 and then filled with the same molten epoxy resin as above to form the back electrode base material 102.

In addition, the electrode base material 63 is comprised from the said front side electrode base material 101 and the back side electrode base material 102.

After the back electrode base material 102 is formed in this manner, it is removed from the back surface of the instrument panel pad 1 as a molded product, thereby forming the counter electrode 62.

As mentioned above, since the counter electrode 62 of this embodiment has the conductive layer 64 provided inside the electrode base material 63, it is possible to prevent the corona discharge from being disturbed at the air outlet 10, 11, and 12 portions, as in the conventional case. Therefore, it is not necessary to provide a dielectric buffer plate in the portion of the counter electrode facing the air outlets 10, 11, 12 to block the air outlets 10, 11, 12. 62 itself can be formed easily and inexpensively, which is effective in reducing equipment costs and improving reproducibility.

[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
It is composed of a Y-axis moving means for moving in the axial direction (back and forth) and a Z-axis moving means 40 for moving in the Z-axis (up and down) 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, the support member 23 is provided on the bottom surface of the turntable 26.
is attached, and both guide rods 28 are inserted through the support member 23, so that the turntable 2
6 is now slidable.

Further, a threaded part 29 is attached to the left and right sides of the support member 23 on the lower surface of the turntable 26, and one screw shaft 27 is threaded into the threaded part 29 so that it can be screwed in and out. There is. 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 screw shaft 27 rotates via the gears 21a and 21b, so the turntable 26 moves in the X-axis direction together with the threaded portion 29 screwed onto the screw shaft 27. It's becoming like that.

Next, in the Y-axis moving means 30, two bearings 35 are provided on each side of the upper surface of the turntable 26. Two screw shafts 31 are rotatably but non-moveably attached between the left and right bearings 35, and both shafts 31 extend parallel to each other in the horizontal direction.
Gears 36a are attached to the front and rear of each screw shaft 31, and 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.
A Y-axis arm 33 extending forward is attached to the central portion of 4. The next Z-axis moving means 40 is fixed to the front end of the Y-axis arm 33.

Therefore, in the Y-axis moving means 30 as well, the rotation of the servo motor 32 is transmitted to the gear 36, the screw shaft 31, and the threaded member 34 in this order, so that the Z-axis moving means 40 moves 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 fixed to the front end of the fixed table 41, and both rods 42
extend parallel to the vertical direction.

A sliding member 44 is slidably attached to both guide rods 42 and extends over them.
A female thread (not shown) is formed in the center of the connector. The female screw has a screw shaft 46 extending upward.
The screw shaft 46 is directly connected to a rotating 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 held at the lower end of the Z-axis arm 43 in a substantially vertical state at all times.

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

The discharge electrode 50 placed in the atmosphere has a rod-shaped gripped portion 5 made of stainless steel with a diameter of approximately 2 mm.
1, the gripped part 5 is also made of stainless steel.
1 and a spherical discharge tip 52 with a diameter of about 6 mm attached to the tip of the discharge tip. As described above, the gripped part 51 is always held in a substantially vertical state by the Z-axis arm 43, and is not tilted even when moved by each of the moving means 20, 30, and 40.

Note that, as shown in FIG. 7, the discharge electrode 50
It is desirable to provide a mesh-shaped shield cylinder 53 made of stainless steel or the like around the . 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 FIGS. 4 and 7, a high frequency applying means C consisting of a high frequency oscillator 16 and a high voltage transformer 17 is connected to the opposing electrode 62 and the discharge electrode 50. Further, as a countermeasure against high frequency noise, the high frequency oscillator 16 is also directly grounded.

High frequency oscillator 16 has 20~30KHZ, maximum output
A product from Tantetsu (trade name: HV05-2) that generates a 350W high frequency 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, and is also a product of Tantec Co., Ltd. (trade name: Super C).

[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 axis moving means 20 for moving the discharge electrode 50 near the surface of the instrument panel pad 1.
an exercise program that controls the operations of 30 and 40;
A program for controlling the start and stop of the high frequency application means C is written therein.

The 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. Also, for the same reason, the high frequency oscillator 16, the high voltage transformer 17 and the discharge electrode 5
The cord connecting 0 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 explained.

First, if the molded instrument panel pad 1 is contaminated with mold release agent or dirt caused by manual work, it is desirable to perform 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 release agent or dirt, or if there is only slight dirt, there is no need to perform pretreatment.

Next, as shown in FIGS. 1, 2, 4, and 5, the instrument panel pad 1 is fitted onto the counter electrode 62 of the counter electrode means A. At this time, since the surface or the entire surface of the counter electrode 62 is formed in substantially the same three-dimensional shape as the back surface of the instrument panel pad 1, the entire surface of the counter electrode 62 reliably contacts the entire back surface of the instrument panel pad 1.

Therefore, almost the entirety of the instrument panel pad 1 made of dielectric PP resin is electrically and effectively coupled to the counter electrode 62, and the distance between the counter electrode 62 and the discharge electrode 50 can be kept small. It becomes possible. As a result, corona discharge is likely to occur from the discharge electrode 50.

Now, if the surface of the counter electrode 62 and the back surface of the instrument panel pad 1 do not come into contact with each other, an air layer is formed between them. This air layer acts as an insulating layer, making it difficult for corona discharge to occur. In this embodiment, this air layer is reliably eliminated to achieve the electrical connection.

Next, after operating the exhaust means E, the control unit D is turned on, and the discharge electrode means B is turned on.
The moving means 20, 30, 40 of each axis are set at the starting position of the corona discharge treatment. At this time, the gripped portion 51 of the discharge electrode 50 is always supported vertically, and the discharge tip 52 is positioned above the left end of the front edge of the instrument panel pad 1 at an interval of about 10 mm.

Next, when the high frequency oscillator 16 of the high frequency applying means C is activated, the high frequency output is transmitted to the high voltage transformer 1.
7, and a high frequency of 28 KV is applied between the counter electrode 62 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,
Corona discharge treatment of the upper surface 2 is started.

The X, Y, and Z axis moving means 20, 30, and 40 are moved in each direction by the rotation of servo motors 25, 32, and 45 that operate based on control signals from the control unit D, and the discharge electrode 50 is It moves near the surface of the instrument panel pad 1.

Note that the moving speed of the discharge electrode 50 can be arbitrarily set within the range of 1 to 250 mm/sec under the discharge conditions, but in this embodiment, sufficient corona discharge treatment effect and shortening of treatment time can be achieved. Taking these into consideration, we decided to set it to 150mm/sec.

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

Further, as shown in FIG. 2, when the discharge electrode 50 passes above the air outlets 10, 11, 12 and the trays 6, 7, the discharge electrode 50 is moved downward by the difference in height. At this time, the counter electrode 62
Since the conductive layer 64 is not exposed in the portion facing the air outlet 10, 11, 12, the corona discharge is not disturbed. Therefore, the air outlet 10,1
The inner surfaces and back surfaces of the plates 6 and 12, the bottoms of the plates 6 and 7, the corner portions 9 and 13, etc. are also reliably and uniformly treated with corona discharge. Furthermore, when adhering the skin sheet, the skin sheet is attached to the air outlet 10,
Even if you wrap it up to the back side of 11 and 12 and glue it,
Corona discharge treatment is applied to the back side, so
Both can be reliably bonded.

The phenomenon of the corona discharge treatment is that a large amount of electron flow caused by the discharge is caused by a synthetic resin (in this example,
It is thought that this is because the impact energy partially breaks the bond between carbon and hydrogen, oxidizes and ionizes the synthetic resin surface, and activates it.

Furthermore, since the corona discharge spreads from the discharge tip 52 in an extremely uniform discharge pattern as shown in FIG.
The surface treatment range is quite wide, and a circle with a diameter of 50 to 60 mm can be sufficiently treated. This is the discharge tip 52
This is because the corona discharge is spherical (curved), so the corona discharge is uniformly dispersed without being concentrated at one point (a sharp part or corner).

As described above, the corona discharge treatment apparatus of this embodiment eliminates the need for large-scale equipment such as a vacuum chamber, vacuum pump, valve mechanism, and carrier gas, as well as the preparation time required to depressurize the vacuum chamber, in conventional plasma processing. Simply by generating corona discharge treatment in the atmosphere using the discharge electrode 50 and moving it,
The surface of the PP resin instrument panel pad 1 can be modified. Therefore, not only can equipment costs and equipment space be significantly reduced, but processing time can also be shortened.

Furthermore, since the discharge electrode 51, at least the discharge tip of which is curved, is moved along the surface of the instrument panel pad 1, the corner portions 5, 8, 9, and 13 can also be treated reliably.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified and embodied as shown below, for example.

(1) The conductive layer 64 of the counter electrode 62 may be made of any metal such as Au, Cu, Al, or Zn, in addition to the conductive paint of the above embodiment.

(2) The conductive layer 64 may be formed by any method such as spray coating in the above embodiments, brush coating, vacuum evaporation, sputtering, etc.

(3) Changing the structure of the X, Y, Z axis moving means 20, 30, 40 in the discharge treatment means B,
Instead of these, an articulated robot or the like may also be used. Further, counter electrode means B
A three-dimensional movement mechanism may be provided to move the instrument panel pad 1 to bring it closer to the discharge electrode 50.

(4) In addition to the above-mentioned instrument panel pad 1, the present invention is applicable to automobile bumpers, automobile moldings, motorcycle mudguard fenders, and various industrial equipment, household goods, etc. that 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 method for manufacturing a counter electrode for corona discharge treatment of the present invention includes an electrode base material formed by transfer to be the same or substantially the same as the back surface of a molded article for corona discharge treatment itself, Since the conductive layer is formed on a conductive layer, it is possible to obtain a counter electrode that can ensure that the entire surface of the counter electrode is in contact with the entire back surface of the molded product. Almost the entirety of the electrode is electrically and effectively coupled to the counter electrode, so that the distance between the counter electrode and the discharge electrode can be kept small. Therefore, in the counter electrode manufactured by this manufacturing method, corona discharge is likely to occur from the discharge electrode,
Even if the molded product has a penetrating part such as a through hole or notch, corona discharge will not be disturbed at the penetrating part.
This provides an excellent effect in that corona discharge treatment can be performed uniformly on any part.

[Brief explanation of the drawing]

1 to 7 show an 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 same cut left and right. , Figure 3 is a perspective view of the instrument panel pad, Figure 4 is a front view of the corona discharge treatment device, Figure 5 is a right side view, Figure 6 is a plan view of the Y-axis moving means, and Figure 7 is a diagram of the discharge electrode and FIG. 3 is a schematic diagram showing a connection with high frequency application means. Instrument panel pad...1, Discharge electrode...50, Counter electrode...62, Electrode base material...63, Conductive layer...
64.

Claims (1)

[Scope of Claims] 1. A step of forming a front-side electrode base material 101 by filling the back side of a three-dimensional molded product having a surface to be subjected to corona discharge treatment with molten resin; a step of providing a conductive layer 64 on the conductive layer 64; a step of forming a back side electrode base material 102 by filling the conductive layer 64 with molten resin; the front side electrode base material 101, the conductive layer 64, and the back side electrode base material 102. A method for manufacturing a counter electrode for corona discharge treatment, comprising the step of removing the electrode from the molded product. 2. The method for manufacturing a counter electrode for corona discharge treatment according to claim 1, wherein the conductive layer 64 is formed of a conductive paint.