JPH0312571B2 - - Google Patents

Description

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

(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.

Traditionally, flame treatment (fire 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 and are thick, conventional counter electrodes placed on the back of the molded product require a wide gap between the counter electrode and the discharge electrode. This has the disadvantage that corona discharge is less likely to occur.

Structure of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a method of corona discharge treating the surface of a resin molded product having a conductive insert member inside. The treatment is performed using the member as a counter electrode of a corona discharge electrode.

(Function) In the present invention, if a part of the conductive insert member is grounded, it can function as a conventional counter electrode. Therefore, the distance between this insert member and the discharge electrode that generates corona discharge on the surface of the molded product can be made much narrower than the distance when a counter electrode is placed on the back surface of the molded product, and it is possible to corona discharge becomes possible.

(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.

As shown in FIG. 1, inside the instrument panel pad 1, a conductive insert member 10 formed in substantially the same shape as the outer shape of the instrument panel pad 1 is embedded at approximately the midpoint between the upper and lower thicknesses. This insert member 10 is formed by bending a conductive metal plate to have substantially the same external shape as the instrument panel pad 1.

Further, as shown in FIG. 4, the instrument panel pad 1 is produced by placing the insert member 10 as an insert in a pair of upper and lower injection molds composed of an upper mold 11a and a lower mold 11b, and molding the PP by injection molding. It is formed by coating with resin.

Since the instrument panel pad 1 is formed by injection molding using the insert member 10 as an insert, the support pin 1 that holds the insert member 10 is inevitably placed in a part of the mold for molding.
2 is required, and a hole 1a for the support pin 12 is formed on the back surface of the instrument panel pad 1 after molding. Therefore, by inserting a grounding pin 13 into the hole 1a and grounding its base end, it can function as a counter electrode used in conventional corona discharge treatment.

Therefore, in this instrument panel pad 1, the distance between the insert member 10 and the discharge electrode that generates corona discharge on the surface of the molded product is
The thickness of the dielectric portion electrically coupled to can be reduced to about half. Therefore, compared to the conventional case where a counter electrode is placed on the back surface of a molded product, the distance between the discharge electrode and the counter electrode can be narrowed regardless of the thickness of the instrument panel pad 1 itself, and corona discharge is reliably produced on the surface of the instrument panel pad 1. It is starting to occur. In this embodiment, an iron plate is used as the conductive metal plate.

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 it is provided with an insert member 10 serving as a counter electrode inside.

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; 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 discharge electrode means B and the insert member 10 inside the instrument panel pad 1; , D: 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. 1, 2, 4, and 5, a hollow support stand 61 is installed on the first stage of the base 80, and the upper part of the support stand 61 has a three-dimensional structure inside the instrument panel pad 1. A receiving member 62 formed to match the shape 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 substantially the same three-dimensional shape as the back surface of the instrument panel pad 1, and reliably fixes the instrument panel pad 1 in which the insert member 10 serving as the counter electrode is embedded. It is now possible to do so.

[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 21ba, 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.
A gear 36a is attached to the front and rear of each screw shaft 31, and each gear 36a meshes with a gear 36b of a servo motor 32 attached to the rear end of the direction 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 conductive insert member 10 and the discharge electrode 50 inside the instrument panel pad 1. The insert member 10 is connected to the ground pin 13 through a hole 1a formed on the back surface of the insert member 10.
As a result, the high frequency applying means C is applied and is also grounded. 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 used to boost the high-frequency output of the high-frequency oscillator 16 and apply a high voltage between the insert member 10 and the discharge electrode 50, and is also used by a product manufactured by Tantech (trade name Spar C). has been done.

[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, in order to move 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. 6, 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 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 mold release agent or dirt, or if the dirt is only mild, there is no need to perform pretreatment.

Next, as shown in FIGS. 1, 2, 5, and 6, the instrument panel pad 1 is placed on the receiving member 62 of the support means A. At this time, since the entire receiving member 62 is formed to have almost 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 insert member 10 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.

At this time, since a conductive insert member 10 serving as a counter electrode is formed inside the instrument panel pad 1, the upper part of the instrument panel pad 1 than the insert member 10 is connected to the insert member 10.
electrically and effectively coupled to the discharge electrode 50
A corona discharge occurs.

If 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, if a three-dimensional and thick molded product is selected, the counter electrode and the discharge The distance from the electrode 50 may become wider, making it difficult for corona discharge to occur on the surface of the instrument panel pad 1. However, in this embodiment, since the insert member 10 serving as a counter electrode is formed in the center of the inside of the instrument panel pad 1, the distance can be narrowed by approximately half the thickness of the instrument panel pad 1. Therefore, the distance between the discharge electrode 50 and the insert member 10 is narrowed regardless of the thickness and shape of the instrument panel pad 1, thereby making the corona discharge reliable and strong.

In other words, the distance between the discharge electrode 50 and the surface of the instrument panel pad 1 can only be narrowed to a certain distance due to molding errors of the instrument panel pad 1. , and its position was moved closer to the discharge ground 50 side.

The X, Y, and Z axis moving means 20, 30, and 40 are moved in respective directions by the rotation of servo motors 25, 32, and 45 that operate based on control signals from the control unit D, and the discharge ground 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 account, 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 (fire 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 about 50 to 60 mm is sufficiently treated.

As described above, in this embodiment, the instrument panel pad 1
has an insert member 10 serving as a counter electrode inside it.
is formed, the insert member 10
The distance between the molded product and the discharge electrode 50 can be narrowed regardless of the thickness of the molded product itself, and corona discharge can be reliably generated.

Further, since there is no need to provide a counter electrode in the corona discharge treatment device as in the conventional case, the corona discharge treatment device can be manufactured at low cost.

Similarly, the supporting means A may have any shape as long as the instrument panel pad 1 is fixed thereto.
By changing only the operating program of the discharge electrode 50, the corona discharge treatment apparatus can be used as a general-purpose machine.

Further, since a metal plate is used as the insert member 10, the strength of the instrument panel pad 1 itself can be increased.

Further, since the instrument panel pad 1 has an insert member 10 formed therein as a counter electrode, corona discharge treatment can be performed on either the front or back surface.

Furthermore, the corona discharge treatment apparatus of this embodiment can significantly reduce equipment costs and equipment space and shorten processing time compared to conventional plasma processing.

Furthermore, since a metal plate is used as the conductive insert member 10 formed within the instrument panel pad 1, it is also possible to improve the strength of the instrument panel pad 1 itself.

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

(1) For the conductive insert member 10, in addition to the metal plate of this embodiment, a powder or liquid material may be used as long as it is conductive.

(2) As the material for the conductive insert member 10, in addition to iron in this embodiment, gold, silver, copper, etc. may be used, carbon black, etc. may be used, or both may be used. A mixture may also be used.

(3) The embedded portion of the insert member 10 is not limited to the approximately central portion of the upper and lower thicknesses of this embodiment, but may be placed at a portion close to the corona discharge treated surface depending on the thickness of the molded product.

(4) In this embodiment, the insert member 1
0 is formed on the entire inside of the instrument panel pad 1, but it is not necessarily necessary to form it on the whole, and it is sufficient to form it only on the inside of the part to be subjected to the corona discharge treatment.

(5) 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.

(6) 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.

(7) In addition to the instrument panel pad 1, the molded product of the present invention can also be used for automobile bumpers, automobile moldings, motorcycle mudguard fenders, and various industrial equipment.
It can be applied to all three-dimensional resin molded products that require painting, adhesion, printing, etc. after molding, such as household goods, and can also be applied to two-dimensional resin molded products. It is. Furthermore, it is effective to incorporate the insert member 10 into a portion that also serves as a reinforcing material.

Effects of the Invention As detailed above, in the corona discharge treatment method of the present invention, the conductive insert member inserted into the molded article for corona discharge treatment is used as a counter electrode of the corona discharge electrode. The conductive insert can be used as a counter electrode as it is, and unlike conventional techniques, a complicated counter electrode (jig) is not required. Furthermore, regardless of the thickness and shape of the molded product, it is possible to narrow the distance between the discharge electrode that generates corona discharge and the counter electrode,
This has the excellent effect of reliably generating corona discharge.

[Brief explanation of the drawing]

1 to 8 show an embodiment embodying the present invention, FIG. 1 is a sectional view showing the instrument panel pad and counter electrode cut in the front and back, and FIG. 2 is a sectional view showing the instrument panel pad and the counter electrode means cut in the left and right directions. 3 is a perspective view of the instrument panel pad, FIG. 4 is a sectional view showing the manufacturing method of the instrument panel pad, and FIG.
The figure is a front view of the corona discharge treatment device, FIG. 6 is a right side view, FIG. 7 is a plan view of the Y-axis moving means, and FIG. 8 is a schematic diagram showing the connection between the discharge electrode and the high-frequency application means. . Insert member...10, Instrument panel pad...
1.

Claims (1)

[Claims] 1. A method for corona discharge treatment of the surface of a resin molded product having a conductive insert member inside, characterized in that the treatment is performed using the conductive insert member as a counter electrode of a corona discharge electrode. Corona discharge treatment method. 2. The corona discharge treatment method according to claim 1, wherein the insert member 10 is formed by bending a conductive metal plate into the shape of a molded product. 3. The corona discharge treatment method according to claim 1, wherein the molded article for corona discharge treatment is formed by injection molding into which the insert member 10 is inserted.