JPH0463094B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) This invention relates to a molded article subjected to corona discharge treatment.

(Prior Art) Polyolefin resins such as polypropylene have few polar groups, so they have the characteristic 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.

(Problems to be Solved by the Invention) 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, a vacuum pump, a valve device, and a carrier gas. There was a problem that it took time to reduce the pressure inside the vacuum chamber. 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 chamber 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, but in this case, a resin mold having the same shape as the back surface of the three-dimensional resin molded product is This requires multiple manufacturing steps, as the surface must be coated with a thin conductive layer to serve as a counter electrode.
The work was extremely tedious.

In addition, if the shapes of the counter electrode formed by the above method and the back surface of the three-dimensional resin molded product do not match accurately, a gap is created between the counter electrode and the three-dimensional resin molded product, and this void In some cases, it became an insulating layer, making it difficult for corona discharge to occur.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention employs a method in which a conductive layer 10 is formed on the back side of the molding for corona discharge treatment.

(Function) Since the molded article of the present invention is subjected to conductive treatment on the back surface which is not subjected to corona discharge treatment, if this conductive treated part is grounded, it can serve as a conventional counter electrode. Therefore, there is no need to separately provide a counter electrode that matches the shape of the back surface of the molded product in the corona discharge treatment apparatus as in the past, and no matter what shape the molded product is formed, There is no gap between the counter electrode and the
Corona discharge can be generated reliably.

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

First, the molded article to be subjected to the corona discharge treatment in this example will be described. This molded article is a three-dimensional resin molded article and has 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, an automobile instrument panel pad (hereinafter abbreviated as an instrument panel pad) 1 made of PP resin as a dielectric material
The instrument panel is constructed by adhering a PVC (polyvinyl chloride) resin skin sheet to its surface.
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.

A conductive paint containing an inductive powder is spray applied to the back surface of the instrument panel pad 1, which is a portion not subjected to corona discharge treatment, to form a thin conductive layer 10. This conductive layer 10 is formed on the entire back surface of the instrument panel pad 1, and by grounding a portion thereof, it functions as a counter electrode used in conventional corona discharge treatment. Therefore, this instrument panel pad 1 can prevent the formation of a gap between the counter electrode and the back surface of the molded product, which occurs in the conventional case, thereby making it difficult for corona discharge to occur. In addition,
In the embodiment, silver powder is used as the conductive powder, and the thickness of the conductive layer 10 is 45 mμ or more.

As mentioned above, the instrument panel pad 1 is a three-dimensional resin molded product, and has many corner parts 5, 8, 9.
The device is characterized in that a conductive layer 10 serving as a counter electrode is provided on the back surface.

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

This corona discharge treatment device is mounted on a base 80 formed of a metal frame in two stages, front and back.The device is divided into two parts: A: A base 80 is used to fix the instrument panel pad 1.
0, and B: a corona discharge treatment and a moving means for three-dimensionally moving the corona discharge treatment; Discharge electrode means B and C: High frequency application means C disposed on the shelf 14 on the left side of the base 80 in order to apply high frequency between the electrode means B and the conductive layer 10 on the back surface of the instrument panel pad 1; : In order to control the electrode moving means B, 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.

[Support means A]

As shown in FIGS. 2 to 5, a hollow support 61 is installed on the first stage of the base 80, and the upper part of the support 61 is shaped to match the three-dimensional shape inside the instrument panel pad 1. A receiving member 62 formed as
is provided to support the instrument panel pad 1 from the inside.

This receiving member 62 can be easily molded by pouring epoxy resin onto the back surface of the instrument panel pad 1 and curing it by reaction.

Therefore, the entire receiving member 62 including its surface is formed to have approximately the same three-dimensional shape as the back surface of the instrument panel pad 1, and the conductive layer 1 serving as the counter electrode
The instrument panel pad 1 on which 0 is formed can be securely fixed.

[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 (vertical) 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 that the turntable 26 moves in the X-axis direction together with the threaded portion 29 screwed onto the screw shaft 27. It's getting old.

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.
are screwed together, and the medicine 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 portion 51 is always gripped in a substantially vertical state by the Z-axis arm 43, and is not tilted even when moved by 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 application means C consisting of a high frequency oscillator 16 and a high voltage transformer 17 is connected to the conductive layer 10 on the back surface of the instrument panel pad 1 and the discharge electrode 50, and the conductive layer 10 is grounded. has been done. In addition, for high frequency noise countermeasures,
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 conductive layers 10 and 50, and is also a product of Tantek 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 interposed therebetween, and have separate and independent power supplies. 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 arranged at a position behind the support means A in the base 80. There is.

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

Next, as shown in FIGS. 2 to 5, the instrument panel pad 1 is fitted into the receiving member 62 of the support means A. At this time, since the entire receiving member 62 is formed in substantially the same three-dimensional shape as the back surface of the instrument panel pad 1, the instrument panel pad 1 can be securely fixed.

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.

The high frequency oscillator 16 of the high frequency applying means C
When 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 10 and the discharge electrode 50. Then, corona discharge occurs in the atmosphere between the part 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.

At this time, since a conductive layer 10 serving as a counter electrode is formed on the back surface of the instrument panel pad 1,
Almost the entire instrument panel pad 1 is electrically and effectively coupled to the conductive layer 10, and the distance between the conductive layer 10 and the discharge electrode 50 can also be reduced.
As a result, corona discharge is reliably generated from the discharge electrode 50.

Suppose that a counter electrode is formed on the surface of the receiving member 62 and the instrument panel pad 1 is placed on the counter electrode, but if the counter electrode is not formed exactly in the same shape as the back surface of the instrument panel pad 1, There is a possibility that a gap may be formed between the counter electrode and the instrument panel pad 1. Since this void acts as an insulating layer, corona discharge treatment is less likely to occur. In this embodiment, since the conductive layer 10 serving as a counter electrode is formed on the back surface of the instrument panel pad 1 itself, the gap can be eliminated and the electrical connection can be achieved.

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 was comparable to that of conventional flame treatment.

Further, as shown in FIG. 7, the corona discharge spreads from the discharge tip 52 in an extremely uniform discharge pattern, and a circle with a diameter of 50 to 60 mm is treated at once.

As described above, if the instrument panel pad 1 of this embodiment is used, it is not necessary to form a resin mold having the same shape as the back surface of the instrument panel pad 1 in the corona discharge treatment apparatus and coat the surface with a conductive layer to serve as a counter electrode. Therefore, the troublesome work described above can be omitted, and the support means A can be manufactured at low cost.

Further, since the supporting means A may be any device to which the instrument panel pad 1 is fixed, it is not necessarily necessary to have the same shape as the back surface of the instrument panel pad 1 as in this embodiment, and therefore only the operating program of the discharge electrode 50 is changed. As a result, the corona discharge treatment apparatus itself can easily be used for corona discharge treatment of other molded products, and the corona discharge treatment apparatus can also be used as a general-purpose machine.

Furthermore, since the instrument panel pad 1 of this embodiment only needs to be coated with the conductive layer 10 on the back surface of the conventionally used instrument panel pad 1, it can not only be realized easily and inexpensively, but also can be implemented easily and inexpensively. It is also possible to prevent corona discharge from occurring due to the formation of voids between the molded product and the molded product.

Moreover, according to the corona discharge treatment apparatus of this embodiment, equipment costs and equipment space can be significantly reduced compared to conventional plasma processing, and processing time can also be shortened.

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 method for attaching the conductive layer 10 may be vacuum deposition, sputtering, ion plating, electron beam, ion implantation, etc. in addition to the spray coating of the conductive paint of this embodiment. A conductive material formed on the surface may be attached.

(2) As the conductive metal, in addition to silver in this embodiment, gold, copper, aluminum, brass, etc. may be used, carbon black may be used, or a mixture of both may be used. You can use

(3) In this embodiment, the conductive layer 10 is formed on the entire back surface of the instrument panel pad 1, but it does not necessarily need to be formed on the entire surface, and may be formed only on the back surface of the portion to be subjected to corona discharge treatment.

(4) In this embodiment, the electrode base material 62 is formed to have almost the same shape as the back surface of the instrument panel pad 1, but this is not necessarily necessary, and any shape may be used as long as the shape allows the instrument panel pad 1 to be fixed.

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

(6) In addition to the above-mentioned instrument panel pad 1, the molded product of the present invention can also be used for automobile bumpers, automobile moldings, motorcycle mudguard fenders, various industrial equipment, household goods, etc. after being molded, such as painting, adhesion, printing, etc. It is possible to materialize it into all necessary three-dimensional resin molded products, and it is also necessary to materialize it into two-dimensional resin molded products.

Effects of the Invention As detailed above, since the molded article for corona discharge treatment of the present invention has a conductive layer formed on the back surface that is not subjected to corona discharge treatment, a resin mold is formed in the corona discharge treatment apparatus and the surface is conductive. Not only does it not require the troublesome work of covering layers and forming a counter electrode, it also prevents the formation of gaps between the conductive layer that will become the counter electrode and the molded product, ensuring corona discharge. It has the excellent effect of being able to

[Brief explanation of the drawing]

1 to 7 show an embodiment embodying the present invention, FIG. 1 is a perspective view of an instrument panel pad, FIG. 2 is a sectional view showing the instrument panel pad and counter electrode means cut horizontally, and FIG. 3 is a cross-sectional view of the instrument panel pad and counter electrode means. 4 is a front view of the corona discharge treatment device, FIG. 5 is a right side view, FIG. 6 is a plan view of the Y-axis moving means, and FIG. 7 is a diagram showing the discharge electrode. FIG. 3 is a schematic diagram showing a connection with high frequency application means. Conductive layer...10, instrument panel pad...1.

Claims (1)

[Claims] 1. A molded article for corona discharge treatment, characterized in that a conductive layer 10 is formed on the back surface. 2. The molded article for corona discharge treatment according to claim 1, wherein the conductive layer 10 is formed by spray coating a conductive paint. 3. The molded article for corona discharge treatment according to claim 1, wherein the conductive layer 10 is formed on the entire back surface of the molded article.