JPS62179531A - Molding for corona discharge treatment - Google Patents

Abstract

PURPOSE:To obtan a high effect of modification, by adding an electroconductive substance to a polyolefin resin before performing midification, such as improvement in adhesion of a printing ink, of a polyolefin resin molding by subjecting it to corona discharge treatment. CONSTITUTION:About 0.1-9pts.wt. electroconductive substance, such as a carbon black powder, is added to 100pts.wt. polyolefin resin such as a polypropylene resin, and the obtained mixture is molded into any desired shape. The obtained molding 1 is placed on a counter electrode 61 and subjected to modification by applying a corona discharge from a discharge electrode 50 to the surface to be treated. In this way, a strong corona discharge can be generated because the electroconductive substance contained in the polyolefin resin forms an electrically contacted chain-like structure and functions as a counter electrode, which is equivalent to shortening of the distance between the counter electrode 6 and the discharge electrode 50. Therefore, a high effect of modification can be attained.

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) 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.

Corona discharge treatment is one of the methods for modifying this polyolefin resin. This corona discharge treatment has traditionally been used as a modification treatment method for resin films, but
No prior art applicable to the present invention has been found.

(Problems to be Solved by the Invention) Therefore, an object of the present invention is to provide a molded article for corona discharge treatment that can obtain a high modification effect by corona discharge treatment.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention is arranged on a counter electrode and performs corona discharge treatment on the surface to be treated by corona discharge from the discharge electrode. It is a molded article for corona discharge treatment, and is made of a material containing a conductive substance in a polyolefin resin.

(Function) Since the molded article of the present invention is made of a material containing a conductive substance in a polyolefin resin, the conductive substance inside the molded article acts as follows to generate strong corona discharge.

■The conductive material forms an electrical chain contact structure and serves as a counter electrode placed on the back of the molded product.

Therefore, the distance between the opposing electrode and the discharge electrode becomes substantially short (as if it were shortened), and a strong corona discharge can be generated.

(2) The inclusion of the conductive substance reduces the proportion of the polyolefin resin which is the dielectric substance in the whole.

Therefore, the thickness of the dielectric becomes substantially thinner, and a strong corona discharge occurs.

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

First, the molded product to be subjected to corona discharge treatment in this example is an automobile instrument panel pad (hereinafter abbreviated as instrument panel pad) as shown in Figs. The instrument panel is constructed by adhering a skin sheet made of (vinyl chloride) resin.

The instrument panel pad l is made of polyolefin resin P.
It is formed by melting and injection molding a material in which P (polypropylene) resin powder 11 contains carbon black powder 12, which is a conductive substance. In this example, the carbon black powder 12 is contained to the extent that it does not change the physical properties of the PP resin serving as the base material, and the carbon black powder 12 is contained in the PP resin 10 with an average particle diameter of about lθ to 100 mμ.
It is contained in 4 parts to 4.5 parts with respect to 0 parts. Further, the content of the carbon blank powder 12 was set to 4 parts to 4.5 parts in this example, but preferably 0.1 parts to 9 parts.
Department. This means that the carbon black content is 0.
．． If it is less than 1 part, the conductivity effect will not be improved, and if it is more than 9 parts, the physical properties of the molded product itself will deteriorate.

As the carbon black, flake powder of acetylene carbon black, which has the best conductivity, is used, but it is used as a pigment for synthetic resins, etc. Conductive carbon black (
Ketjenblack) may also be used.

Incidentally, when the content of the carbon blank is increased, the rigidity improves, but the impact resistance decreases, so an impact resistance improver (rubber, elastomer, etc.) may be added as appropriate.

Therefore, by including carbon black, which is the conductive substance, the surface of the instrument panel pad 1 can be improved even when a corona discharge treatment device with the same high frequency output is used, compared to a conventional molded product that does not contain a conductive substance. A strong corona discharge occurs between the electrode and the discharge electrode, which will be described later, and a high reforming effect can be obtained.

The instrument panel pad l 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.

Furthermore, two shallow dish portions 6.7 are provided on both left and right sides of the upper surface 2 of the instrument panel band. 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 described above, the instrument panel pad 1 is characterized by being a three-dimensional resin molded product made of a polyolefin resin containing a conductive substance.

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

This corona discharge treatment device is placed on a base 80 formed of two stages, front and back, with a metal frame.The device is divided into two parts: A: An instrument panel pad l is fixed, and a counter electrode is contacted to the back surface of the instrument panel pad l. In order to do this, the counter electrode means A is disposed on the first stage of the base 80, and the counter electrode means B is provided with a corona discharge treatment and a moving means for three-dimensionally moving the corona discharge treatment. C: In order to apply a high frequency between the discharge electrode means B and the insert member 10 inside the instrument panel pad 1, the discharge electrode means B is arranged on the second stage. It is composed of a high frequency applying means C arranged, and a control unit D grounded on the right side of the base 80 in order to control the electrode moving means B.

Hereinafter, the details of each of the sections A to D will be explained in order.

[Counter electrode means A]

As shown in Figures 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 formed to match the three-dimensional shape of the back surface of the instrument panel pad 1 is provided on the top of the instrument panel pad 1.
The instrument panel pad 1 is supported from the back side.

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

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 full bend plating method, and the electrode base material 62 and the conductive layer 63 are opposed to each other. An electrode 60 is configured. Therefore, the entire counter electrode 60 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 surface of the conductive layer 63 is in contact with the back surface of the instrument panel pad 1. It has become.

[Discharge electrode means B]

As shown in FIGS. 4 to 6, the discharge electrode means B includes a corona discharge bridge 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 back). The Y-axis moving means to move the
Z-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 Y-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 2
6 is slidable.

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 Y-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 portion of the cough threaded member 34. Y
A 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.

Both guide rods 42 have one sliding member 44 spanning them.
The sliding member 44 is mounted so as to be movable, and a female thread (not shown) is formed in the center of the sliding member 44 . A screw shaft 46 extending upward is engaged with the female thread, and 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 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 has a rod-shaped gripped part 51 made of stainless steel with a diameter of about 2 l, and a gripped part 51 made of stainless steel with a diameter attached to the tip of the gripped part 5. It consists of a spherical discharge tip 52 of about six fins. 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, 40
It is designed so that it does not tilt even when it is 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, 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 63 on the surface of the counter electrode 60 and the discharge electrode 50. It 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
Tantic'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 insert member IO and the discharge electrode 50, and is also used by Tantic's product (trade name Spar C). has been done.

[Control unit p]

A control circuit (not shown) using a computer or the like is incorporated in the aflll 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 L. An exercise program for controlling the operation of the .30.40, a program for controlling the start and stop of the 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 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 of all, if the molded instrument panel pad l is contaminated with mold release agents or dirt caused by manual work, it is desirable to perform pretreatment to clean it with an organic solvent such as trichloroethane. This is to perform corona discharge treatment.

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 entire counter electrode 60 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 movable element 1' of each axis in the discharge electrode means B is moved! 20. Set 30.40 at the start position of 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 positioned above the left end of the front edge of the instrument panel pad 1 at an interval of approximately IQms.

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 high frequency of 28 KV 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 each direction by the rotation of a servo motor 25, 32, 45 operated based on a control signal from the control unit D, and the discharge electrode 50 is 10 moving near the surface.

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

The entire surface of the instrument panel pad 1 is corona discharge treated by the corona discharge treatment accompanied by the above-described reciprocating movement, and the adhesion of adhesives and the like is improved. 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.

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

As described above, according to this embodiment, the instrument panel pad 1 is made of a material in which carbon black powder 12 is contained in the PP resin powder 11 serving as the base material, so that strong corona discharge can be achieved with the same high frequency output as the conventional one. can be generated, and an extremely high reforming effect can be obtained.

The reason why this high reforming effect is obtained is considered to be due to the following.

(2) The carbon black powders 12 come close to each other to form an electrical chain contact structure and serve as the conductive layer 63, so that the distance between the conductive layer 63 and the discharge electrode 50 is substantially reduced. This is the same as narrowing down to . Therefore, a strong corona discharge is generated, and a high reforming effect can be obtained.

■Containing the carbon black powder 12 substantially reduces the amount of PP resin that serves as a dielectric, so the proportion of the dielectric portion in the entire molded product decreases, and the thickness of the molded product becomes substantially thinner. It will be similar. Therefore, similar to (2), a strong corona discharge is generated, and a high reforming effect can be obtained.

As described above, if the instrument panel pad 1 of this embodiment is used, a stronger corona discharge can be generated even if the same high-frequency output as the conventional one is used, so that a high reforming effect can be obtained. Therefore, the corona discharge treatment can be carried out in a short time, the cost of the treatment can be reduced, and the cost of assembling the molded product as a whole can also be reduced.

In addition, carbon black powder 1 contained in the molded product itself
Since the modification effect on the surface of the molded product can be changed by changing the content of The discharge treatment time can be set freely.

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

(1) In addition to the carbon black powder 12 of this embodiment, the conductive material may be metal powder such as gold, silver, or copper, or fully bent fiber, or may be an alloy such as Hastelloy.

(2) The carbon black powder 12 is not only the acetyl carbon blank of this example but also SA which is hard carbon.
F, 15AF, HAF, soft carbon FET
, HMF, GPF, etc. may also be used.

(3) As the polyolefin resin, in addition to the PP resin of this embodiment, polyethylene resin, polystyrene resin, polyester resin, etc. may be used.

(4) 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.

(5) In addition to the above-mentioned instrument panel pad 1, the molded product of the present invention can be used for automobile bumpers, automobile moldings, motorcycle mudguard fenders, various industrial equipment, household goods, etc. After molding, painting, adhesion, printing, etc. The present invention can be applied to all three-dimensional resin molded products that require the following, and can also be applied to two-dimensional resin molded products such as resin glass and resin films.

Effects of the Invention As detailed above, since the molded article for corona discharge treatment of the present invention is made of a material containing a conductive substance in a polyolefin resin, it can generate strong corona discharge, In addition to obtaining a high reforming effect, by adjusting the content of the conductive substance, it is possible to control the modification state of the surface to be treated, which is related to the high frequency output of the corona discharge treatment device. play.

[Brief Description of the Drawings] Figures 1 to 7 show an embodiment embodying the present invention.
The figure is a cross-sectional view showing the instrument panel pad and the counter electrode means cut front and back, Figure 2 is a cross-sectional view similarly cut left and right, Figure 4 is a front view of the corona discharge treatment device, and Figure 5 is the same right side. 6 is a plan view of the Y-axis moving means, and FIG. 7 is a schematic diagram showing the connection between the discharge electrode and the high frequency application means. Instrument panel pad...l Discharge electrode...50 Counter electrode...60 Patent applicant Toyoda Gosei Co., Ltd. Agent Patent attorney On 1) Hironobu Figure 8 Figure 6

Claims (1)

[Claims] 1. A discharge electrode (50) disposed on the counter electrode (60);
A molded article for corona discharge treatment (1) in which a surface to be treated is subjected to corona discharge treatment by corona discharge from the mold, and is characterized by being made of a material containing a conductive substance in a polyolefin resin. Molded products for corona discharge treatment. 2. The polyolefin resin is a polypropylene resin, and the conductive substance is carbon black powder (12)
and this carbon black powder (12) is contained in a ratio of 0.1 part to 9 parts with respect to 100 parts of the polypropylene resin.
A molded article for corona discharge treatment as described in .