JPH0359095B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a counter electrode for corona discharge treatment used for corona discharge treatment of various products such as synthetic resins and glass.

(Prior Art) Various products made of polyolefin-based synthetic resins have few polar groups in the polyolefin-based synthetic resin, so paints, adhesives,
It has the characteristic that printing etc. are difficult to adhere to. Therefore, when applying paint, adhesion, printing, etc. to the surface of the product, it is necessary to perform a modification treatment on the surface as a pretreatment to improve the adhesion.

As a modification treatment for products made of polyolefin-based synthetic resins, the applicant has focused on corona discharge treatment, which is performed as a modification treatment for resin films. There are many difficulties in applying it.

One of these is that when products have various three-dimensional shapes, conventional roll-shaped or flat-shaped counter electrodes for corona discharge treatment (hereinafter simply referred to as "counter electrodes") may This is problematic in that a large air layer is created between the two, and the distance between the discharge electrode and the discharge electrode becomes large, making it impossible for corona discharge to occur.

Therefore, it has been considered to form the counter electrode in substantially the same shape as the back surface of the three-dimensional resin product, and in this case, an electrode base material having the same shape as the back surface of the three-dimensional resin product is formed. This surface is coated with a thin conductive layer.

(Problems to be Solved by the Invention) However, the following problems can be considered with the counter electrode formed by the above method.

That is, when the three-dimensional resin product is provided with an opening such as a through hole or a notch, the conductive layer is exposed from that part to the discharge electrode side. Therefore, when a discharge electrode undergoing corona discharge is located in the opening, intense sparks will be created between the discharge electrode and the conductive layer to disturb the corona discharge, and the surface adjacent to this opening will be sufficiently corona-discharged. Discharge treatment may not be possible.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a protective layer that comes into contact with the back side of the surface to be treated of a product to be subjected to corona discharge treatment, and a protective layer on the back side of the protective layer. In the counter electrode for corona discharge treatment constituted by the formed conductive layer, the portion of the protective layer exposed through the opening formed in the product is covered with a heat-resistant resin.

(Function) By employing the above means, the present invention functions as follows.

During corona discharge treatment, if the corona discharge electrode moving above the product is located above or close to the opening formed in the product, the opening and the counter electrode will directly oppose each other. Since a protective layer covering the conductive layer is formed on the counter electrode, it is possible to reliably prevent corona discharge from being disturbed in this portion.

Further, since a coating layer with excellent heat resistance is formed on the protective layer facing the opening, thermal deformation of this coating layer is reliably prevented even if corona discharge is repeated.

(Example) This invention will be described below as a three-dimensional synthetic resin product for an automobile instrument panel pad (hereinafter referred to as
An embodiment in which a counter electrode for corona discharge treatment is applied to an instrument panel pad will be described with reference to FIGS. 1 and 2.

First, the instrument panel pad 2 that is placed on the surface of the counter electrode 1 of the present invention and subjected to corona discharge treatment will be described.

The instrument panel pad 2 has a substantially horizontal U-shape in cross section, and is formed into a three-dimensional shape from a front surface 3, an upper surface 5 having two through holes 4, and a rear surface 6. After discharge treatment, PVC (polyvinyl chloride) is applied to the surfaces of these surfaces 3, 5, and 6.
A resin skin sheet (not shown) is attached.

Next, an apparatus for performing corona discharge treatment on the surface of the instrument panel pad 2 will be explained.

The corona discharge treatment apparatus used in this method includes a high frequency application means B, an electrode moving means C, a corona discharge electrode 18 whose tip is a spherical ball electrode attached to the tip of the electrode moving means C, and a corona discharge electrode 18 whose tip is a spherical ball electrode. It is comprised of a counter electrode means D provided to face the electrode 18, and a control unit E for controlling the high frequency application means B and electrode moving means C.

The counter electrode means D is in contact with the back surface of the instrument panel pad 2, and has a counter electrode 1 formed of a protective layer 11 having a constant thickness and a conductive layer 12 formed on the back surface of the protective layer 11 by metal spraying. , and an electrode base material 13 formed on the back surface of the conductive layer 12 so as to cover the conductive layer 12.

Of the protective layer 11, the instrument panel pad 2
A coating layer 10 made of a heat-resistant epoxy resin with excellent heat resistance is formed only on the portion exposed from the through hole 4 . This prevents the conductive layer 12 and the corona discharge electrode 18 from directly opposing each other, and also prevents thermal deformation due to corona discharge because the coating layer is made of a heat-resistant epoxy resin.

The synthetic resin with excellent heat resistance refers to a synthetic resin having a softening temperature of 100°C or higher, preferably a melting temperature of 180°C or higher.

As shown in FIG. 2, the conductive layer 12 is formed by spraying a highly conductive metal melted by arc spraying from a thermal spraying machine 14 onto the entire back surface of the protective layer 11. It is formed by twisting. The arc spraying method generates an arc between two metal wires by applying a high DC voltage between the two metal wires, and converts the metal melted by the arc into microparticles on the order of μm. This is a method of spraying using high-pressure compressed air, and the thermal spray machine 14 sprays fine particles on the order of μm.

In this embodiment, Cu, which is a highly conductive metal, is sprayed to a thickness of about 6 μm to 20 μm, so that the overall resistance of the conductive layer 12 is 10 Ω/□. Therefore, this conductive layer 12 follows the three-dimensional shape of the back surface of the protective layer 11, is formed to have a substantially uniform thickness in all parts, and has extremely high conductivity. Further, one end of the conductive layer 12 is grounded and connected to a high voltage transformer 20, which will be described later.

The electrode base material 13 is made of ordinary epoxy resin so that the conductive layer 12 is not exposed to the outside. This is to prevent severe sparks from being generated between the exposed portion and the corona discharge electrode 18 during corona discharge if the conductive layer 12 is exposed.

The high frequency applying means B is composed of a high frequency oscillator 19 that generates high frequency waves, and a high voltage transformer 20 that boosts the high frequency waves generated therein. As the high frequency oscillator 19, for example, 20 to 30K
Hz, a product manufactured by Tantetsu Co., Ltd. (product name HV05-2) that generates high frequency waves with a maximum output of 350 W is used, and the high voltage transformer 20 is also a product made by Tantech Co., Ltd. (product name Super C). Therefore, a high frequency of 0 to 350 W is applied between the corona discharge electrode 18 and the conductive layer 12.

The electrode moving means C is constituted by a moving mechanism (not shown) for moving the corona discharge electrode 18 to an arbitrary position in a three-dimensional direction, and is connected to the control unit E. The control unit E is constituted by a microcomputer or the like, and has a motion program for operating the control means C and a program for controlling the start and stop of operation of the high frequency application means B being written therein.

Next, in order to subject the surface of the instrument panel pad 2 to corona discharge treatment using the corona discharge treatment apparatus configured as described above, the instrument panel pad 2 is placed on the surface of the protective layer 11, and the switch of the control unit E is turned on. Turn on.

Then, the electrode moving means C uses the moving mechanism to move the corona discharge electrode 18 to a position close to the edge of the rear surface 6 of the instrument panel pad 2 (indicated by the two-dot chain line in FIG. 1), which is the starting position of the corona discharge treatment.
Move to. Thereafter, the high frequency application means B is activated, and the gap between the corona discharge electrode 18 and the conductive layer 12 is
While applying a high frequency of 28 KV, it moves three-dimensionally along the shape of the surface of the instrument panel pad 2 (as shown by the dashed-dotted arrow in FIG. 1). Therefore, corona discharge occurs between the corona discharge electrode 18 and the surface of the instrument panel pad 2, and these surfaces 3, 5, 6
A corona discharge treatment is performed.

At this time, when the corona discharge electrode 18 is located above the through hole 4, the corona discharge electrode 18 moves downward in order to uniformly apply corona discharge treatment to the through hole 4 and the side wall. Therefore, the protective layer 1
1 and a corona discharge electrode 18 are in close proximity to each other, and corona discharge is performed directly to this counter electrode 1. However, since the counter electrode 1 has a protective layer 11 covering the conductive layer 12 formed on its surface, this This can prevent violent sparks from occurring in some areas and disrupting corona discharge. Therefore, the entire instrument panel pad 2 can be uniformly subjected to the corona discharge treatment.

Furthermore, since the coating layer 10 made of a heat-resistant epoxy resin with excellent heat resistance is formed on the portion of the protective layer 11 that is exposed through the through hole 4 of the instrument panel pad 2, this portion can be prevented from being deformed by heat. As a result, the life of the counter electrode 1 itself can be extended. Furthermore, the amount of relatively expensive heat-resistant epoxy resin used can be reduced, and even if there are air bubbles in the protective layer 11, sparks can be prevented in these areas.

Further, the back surface of the protective layer 11 is made of highly conductive Cu.
Since the conductive layer 12 is formed by depositing by a metal spraying method, the conductivity of the conductive layer 12 can be increased, and the discharge efficiency in corona discharge can be increased. Furthermore, since the conductive layer 12 is formed by metal spraying, even if the protective layer 11 has a complicated three-dimensional shape,
The Cu can be easily formed to have a uniform thickness on each part of the back surface of the protective layer 11. Therefore, uniform corona discharge can be generated in any part of the instrument panel pad 2.

Further, since a ball electrode with a spherical tip is used as the corona discharge electrode 18, corona discharge can be uniformly emitted from the ball electrode to the side surfaces of each through hole 4, and corona discharge treatment can be performed efficiently.

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) As the electrode moving means C, it is also possible to use the device described in the application previously filed by the present application (Patent Application No. 61-282596).

(2) In each of the above embodiments, a device for performing corona discharge treatment on the instrument panel pad 2 was used. In addition, a device used as a pre-treatment process for the painting process of mudguards and side moldings, and a hair-planting process for roof headers and front pillars are also used. It can be embodied in an apparatus or the like used as a pretreatment process.

(3) In the above embodiment, the present invention was embodied in the counter electrode 1 for corona discharge treatment of a synthetic resin product.
It can also be embodied as a counter electrode 1 for corona discharge treatment on glass products.

(4) In the above embodiment, arc spraying, which is an electric spraying method, was used as the metal spraying method, but other methods include plasma spraying, wire blast spraying, and
Flame spraying and explosion spraying can be used as gas spraying methods.

(5) If the protective layer 11 is made of a material with low adhesion to the metal to be thermally sprayed, a primer layer may be provided.

(6) The metal forming the conductive layer 12 is the metal of this embodiment.
In addition to Cu, metals such as Au, Ag, Zn, and Al, and alloys with high conductivity can be used.

(7) The method of forming the conductive layer 12 includes, in addition to the metal spraying method of this embodiment, pasting conductive aluminum foil, forming a metal layer by vapor deposition, and applying conductive paint. It may be used for methods such as

Effects of the Invention As detailed above, in the present invention, when corona discharge treatment is performed on a product having an opening, the corona discharge electrode and the conductive layer are prevented from directly facing each other even in the opening, so Corona discharge treatment can be applied uniformly to the entire surface, and since the portion exposed from the opening is a protective layer of heat-resistant resin, thermal deformation due to corona discharge does not occur, and as a result, the life of the counter electrode itself is shortened. It gets longer,
Furthermore, since only the portion exposed from the opening is made of heat-resistant resin, various excellent effects such as less use of expensive heat-resistant resin can be achieved.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is an explanatory view showing a method of forming a conductor on the back surface of an electrode base material by metal spraying. DESCRIPTION OF SYMBOLS 1... Counter electrode, 2... Product subjected to corona discharge treatment, 11... Protective layer, 12... Conductive layer, 13...
...Electrode base material.

Claims (1)

[Scope of Claims] 1. A product for corona discharge treatment that is composed of a protective layer 11 that comes into contact with the back side of the surface to be treated of the product 2 to be subjected to corona discharge treatment, and a conductive layer 12 formed on the back side of the protective layer 11. A counter electrode for corona discharge treatment, wherein a portion of the protective layer 11 exposed from an opening formed in the product 2 is covered with a heat-resistant resin 10. 2 The heat-resistant synthetic resin is a heat-resistant epoxy resin,
The counter electrode for corona discharge treatment according to claim 1, characterized in that it is a fluororesin, a silicone resin, a nylon resin, a polyester resin, or a polyphenylene oxide resin.