KR890004070B1 - Surface treatment method of polyolefin molding - Google Patents

Abstract

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Description

Surface treatment method of polyolefin molding

1 is a perspective view of an installation panel pad.

2 is a front view of the corona discharge treatment apparatus.

3 is a partially broken side view of the corona discharge treatment apparatus.

4 is a plan view of the Y-axis moving means.

5 is a front side view of the corona discharge electrode used in the first embodiment.

6 is a sectional view of the counter electrode means.

7 is a sectional view of the cleaning apparatus.

Fig. 8 is a perspective view showing the front end of the pedestal and corona discharge electrode of the second embodiment.

* Explanation of symbols for the main parts of the drawings

1: mounting panel pad 81: stand

50,82: corona discharge electrode 71: cleaning tank

The present invention relates to a surface treatment method of a polyolefin-based molding in which painting, printing ink or adhesive is applied to the surface.

In the prior art, polyolefin-based synthetic resins such as polypropylene (PP) and polyethylene (PE), or polyolefin-based synthetic rubbers such as ethylene-propylene-diene terpolymer copolymer rubber (EPOM) and ethylene-propylene copolymer rubber (EPM) are polar groups in the molecule. The adhesiveness is insufficient even when a coating material, a printing ink or an adhesive is applied to the surface of the molded article made of the resin or rubber.

Therefore, in the case of coating, adhering, printing or the like on the surface of the molded article, it is necessary to improve the adhesion by applying a modification treatment on the surface as a pretreatment.

As the modification treatment of the above-mentioned polyolefin-based molding, conventionally, a chemical modification treatment such as physical modification treatment such as plasma treatment or corona discharge treatment or dichromic acid-converted mixed mixture treatment or trichloro-ethylene washing has been adopted.

The plasma treatment is performed by introducing plasma gas into a vacuum chamber, so that almost the entire surface of the molded article can be modified at once, and is used as a pretreatment for automobile shock absorbers, pedestals, and the like.

In addition, the corona discharge treatment is used only for the modification treatment of thin film-shaped moldings, because the molded articles can be modified by pushing the molded articles between adjacent electrodes.

However, there is no conventional technique for corona discharge treatment of a molded article having a three-dimensional shape.

Unlike plasma treatment, corona discharge treatment can be performed in the air without the need for a vacuum chamber, and thus, a large amount of the workpiece can be processed in a short time.

However, the conventional corona discharge treatment has a problem that the three-dimensional molded article having a three-dimensional effect cannot be pushed because the distance between the electrodes is extremely narrow, about 3 to 4 mm.

In particular, polyolefin-based moldings are difficult to adhere to paints, printing inks or adhesives, as described above, and thus, when the chemical reforming treatment and the corona discharge treatment are used together, the three-dimensional shape can be achieved despite the effective reforming treatment in a short time. In the case of the prepared polyolefin-based molded article, a technique for corona discharge treatment was not found. Therefore, the surface treatment method using the above chemical reforming treatment and the corona discharge treatment is not currently employed.

Therefore, the present invention cleans the surface of a polyolefin-based molded article having a three-dimensional shape with an organic solvent, and then, while the corona discharge electrode having the shape of a discharge portion is a sphere, a rod, or a surface while generating a corona discharge in the vicinity of the molded article, The above problems are solved by adopting the surface treatment method of the polyolefin-based molded product, which is relatively moved according to the surface shape.

In addition, the polyolefin-based molded article having a three-dimensional shape to be modified by the present invention is a molded article made of polyolefin-based synthetic resin such as PP or PE, or polyolefin-based synthetic rubber such as EPOM or EPM. It has a dimensional uneven shape.

By cleaning the surface of the polyolefin-based molded product with an organic solvent, oils and the like are first removed, and the surface is smoothed by the organic solvent and is easily modified by corona discharge treatment.

Then, the corona discharge treatment is performed using an electrode whose shape of the discharge portion is suitable for the surface shape of the polyolefin-based molded article such as spheres, rods or faces, thereby making it possible to uniformly and quickly modify the surface thereof.

Hereinafter, a first embodiment in which the present invention is embodied will be described with reference to FIGS.

As shown in FIG. 1, the polyolefin molded article surface-treated by the present embodiment is an installation panel pad (hereinafter, referred to as an installation panel) of an automobile formed of PP resin (1), and vinyl chloride (PVC) on this surface. The resin skin sheet is bonded to form a mounting panel product.

The installation panel 1 has a protruding corner portion 5 at the boundary between the upper surface 2 and the front surface 3, the boundary between the upper surface 2 and the side surface 4, and R of the corner portion 5 is approximately. 6mm.

In addition, two shallow dish parts 6 and 7 are provided on the right side of the upper surface 2 of the mounting panel 1. Accordingly, convex corners 8 are formed at the upper edges of the shallow plates 6 and 7, and concave corners 9 are formed at the lower edges of the shallow plates 6 and 7, respectively. R is about 6mm.

In addition, two ventilation and air conditioning air outlets 11 and 12 are formed at the left and right sides of the front surface 3, and a side frost removal air outlet 10 is formed at the left end of the upper surface 2, respectively. . The temporary outlets 10, 11, and 12 have a substantially rectangular shape, and corners 13 of which R is 6 to 15 mm are formed at the edges and four corners thereof.

Next, the surface treatment apparatus used in the present embodiment will be described.

7 is a manufacturing apparatus used in the present embodiment, the bottom of the cross-sectional rectangular metal washing tank 71 is the installation panel 1, i.e., an organic solvent 72 having a solubility parameter equal to or similar to that of the PP resin. (Trichloroethylene in this example) is filled

In the organic solvent 72, a heater for temperature control function is deposited so that the organic solvent 72 is maintained at a large boiling temperature (87 ° C in the case of trichloroethyllan).

In the cleaning tank 71, a metal net 74 is provided in the center of the cleaning tank 71 for mounting the workpiece, and a cooling tube having a hole therein for circulating the cooling water therein. 75 is provided, and the vapor | steam of the said organic solvent 72 cools in the surface of this cooling pipe 75, and falls to the bottom in the washing tank 71. As shown in FIG.

The organic solvent filled in the cleaning tank 71 is preferably selected to have a solubility parameter that is equal to or close to the solubility parameter of the polyolefin which is the base member of the object to be processed.

That is, when treating the same PP resin (solubility parameter = 8.0) as in this example, trichloroethylhen (solubility parameter = 9.2), trichloro ethane (9.6), cyclochloroethylene (9.1), ethyl chloride (9.2), pentachloro ethylene (9.4) tetrachloro ethylene (9.3), ethylene chloride (9.7). Chlorinated organic solvents such as ethylene sichloride (9.8) and acetyl chloride (9.5), aromatic organic solvents such as benzene (9.2), toluene (8.9) xylene (8.8), chlorotoluene (8.8), and chlorobenzene (9.5) This is suitable.

As shown in Figs. 2 to 4, the electric discharge treatment apparatus used in the present embodiment is constituted by the following means, and the means are provided on a two-stage scaffolding base A and divided into its side parts.

In other words, the corona discharge treatment apparatus is the second of the high frequency applying means (B) and the base (A), which are composed of a high frequency oscillator (16) and a high frequency transformer (not shown) provided on the left shelf (14) of the base (A). Opposite electrode means (D) fixed to the first stage of the base A so as to face the electrode movement means (C) arranged at the stage and the discharge electrode (50) held by the electrode movement means (C). ) And a control unit E provided on the right side of the base A to control the electrode movement means C.

In the high frequency application means B, the high frequency oscillator 16 uses the product of Dantec Inc. (brand name "HV-05-2") which produces a high frequency of 20-30 KHz and a maximum output of 350W.

In addition, since the high voltage transformer boosts the high frequency from the high frequency oscillator 16 and applies a high voltage to the electrode for corona discharge, the product of Dantec Corporation (brand name "Super-C") is used.

The electrode moving means C is similarly shown by the arrow Y to the X axis moving means 20 for moving the corona discharge electrode 50 in the X axis (left and right) directions shown by the arrow X. Y-axis moving means 30 for moving in the Y-axis (front and rear) direction, and Z-axis moving means 40 for moving in the Z-axis (up and down) direction shown by arrow Z.

In the X-axis moving means 20, two guide rods 28 are fixed on the base table A in parallel and horizontal directions.

The guide rod 28 is provided with a turntable 26 for holding the Y axis moving means 30 so as to be slidable in the X axis direction. In addition, a support member 23 having a screw fitting portion 29 is provided on the lower surface of the turntable 26, and the two guide rods 28 are pushed into the support member 23.

In addition, one screw shaft 2 is screwed into the screw fitting portion 29 between the two guide rods 24, and a gear 21a is provided at one end thereof. The gear 21a is engaged with the gear 21b of the rotation shaft 22 of the servo motor 25, and the rotation of the servo motor 25 is transmitted to the spiral shaft 27.

Therefore, the rotation of the servo motor 25 is converted to the displacement of the turntable 26 and the Y-axis moving means 30 moves in the X-axis direction.

As shown in FIG. 4, two bearings 35 are provided on both sides of the turntable 26 in the Y-axis moving means 30, and two spiral shafts 31 are provided on the bearings 35, respectively. It is rotatable and at the same time impossible to advance, and both shafts 31 are parallel to each other and extend in the horizontal direction. Gears 36 are provided at one end of the spiral shaft 31 and are connected to the rotary shaft 37 of the servo motor 32.

The two screw shafts 31 are screwed with a screwing member 34 that extends over the same shaft 31, and the lower end of the Y-axis arm 33 extending forward is installed at the center of the screwing member 34. It is. In addition, the Z-axis moving means 40 is fixed to the other end of the Y-axis arm 33.

Therefore, even in the Y-axis moving means 30, the rotation of the servo motor 32 is transmitted to the gear 36, the spiral shaft 31, and the screwing member 34, and the Z-axis moving means 40 moves in the Y-axis direction. It becomes active.

In the Z-axis moving means 40, a plate-shaped fixing table 41 is fixed vertically to the other end of the Y-axis arm 33. In addition, two guide rods 42 are fixed to the front side of the fixed table 41 in parallel and up and down directions, and sliding members 44 covering the guide rods 42 are slidably movable on both guide rods 42.

A screw shaft 46 extending upward is screwed into a screw (not shown) provided in the central portion of the sliding member 44, and the spiral shaft 46 is a servo motor 45 provided on an upper portion of the fixed table 41. Is directly connected to the rotating shaft 47.

On the other hand, the upper end of the Z-axis arm 43 extending downward is fixed to the center part of the sliding member 44, and the corona discharge electrode 50 is hold | maintained at the lower end.

Therefore, when the servo motor 45 is rotated, the spiral shaft 46 rotates so that the Z-axis arm 43 and the corona discharge electrode 50 are raised and lowered via the sliding member 44.

A control circuit (not shown) using a microcomputer or the like is assembled in the control unit E, and the control circuit E includes X, Y, and the like in order to move the corona discharge electrode 50 near the surface of the installation panel 1. An exercise program for controlling the operation of the Z-axis moving means 20, 30, 40 and a program for controlling the start and stop of the operation of the high frequency applying means B are written.

Moreover, the exhaust means F for discharging gas, such as ozone which arises at the time of a corona discharge process, is provided in the inner lower part of the base A.

The corona discharge electrode 50 held at the tip of the Z-axis arm 43 is connected to the high frequency oscillator 16. The electrode 50 is made of stainless steel, and as shown in FIG. 5, a rod-shaped gripping portion 51 having a diameter of about 2 mm and a tip of the gripping portion 51 having a radius of about 2.5 mm are formed. It is comprised from the discharge front part 52. As shown in FIG.

As shown in FIG. 5, a number of hemispherical protrusions 53 are formed on the surface S of this discharge tip portion 52 for the purpose of improving current collection efficiency.

Next, the counter electrode means D is provided below the corona discharge electrode 50 at an upper surface of the first stage of the base A. As shown in FIG.

In this counter electrode means D, a ladder-shaped electrode stand is provided on the base A as shown in FIG. The counter electrode base 62 is formed on the electrode stand 61 so as to conform to the shape of the rear surface of the mounting panel 1, and the counter electrode 63 is metal plated, vacuum deposited, sputtered, conductive paint coated on the surface thereof. And coating are formed by means such as aluminum foil adhesion.

The back surface of the mounting panel 1 is brought into contact with the upper surface of the counter electrode 63, but each outlet 10, 11, 12 of the mounting panel 1 is placed with a buffer plate 15 such as rubber from the back surface thereof. The counter electrode 63 is not exposed.

In addition, the counter electrode base material 62 can be obtained by, for example, using an installation panel 1 as a molding die and injecting an epoxy resin into the back surface thereof to cure the reaction.

The method of modifying the surface of the installation panel 1 using the washing | cleaning apparatus and corona discharge treatment apparatus comprised as mentioned above is demonstrated.

First, the installation panel 1 is mounted on the net 74 in the cleaning tank 71. The washing tank 71 is filled with steam of trichloroethylene so that the trichloroethylene is warmed to its boiling temperature in advance, and the surface of the installation panel 1 is free of dust, oil, and the like, which are cleaned by the medium. At the same time, the surface is smooth by trichloroethylene and is in a state of being easily modified by the corona discharge treatment described later.

After removing the installation panel 1 cleaned in the cleaning tank 71 for about 30 seconds, trichloroethylene attached to the surface was evaporated by heating and drying. Next, as shown in FIG. 2 and FIG. 3 and FIG. 6, the mounting panel 1 is fitted over the counter electrode means D so that the back surface of the counter electrode 63 and the mounting pin 1 come into contact with each other. It was.

By operating the exhaust means (F), the control unit (E) is switched on, and the X, Y, Z axis movement means (20, 30, 40) of the electrode movement means (B) are set to the start position of the corona discharge treatment. The high frequency application means B was then activated. In this case, the distance between the tip of the corona discharge electrode 50 and the installation panel 1 is 10 mm, and a high frequency of 28 KV is applied between the corona discharge electrode 50 and the counter electrode 63.

The corona discharge treatment is started in which the corona discharge is scanned from the discharging tip 52 of the corona discharge electrode 50 to the installation panel 1. The X, Y and Z axis moving means 20, 30 and 40 move by the rotation of the servo motors 25, 32 and 45 based on the signal from the control unit E, and the corona discharge electrode 50 The installation panel 1 is moved from the right end to the left end at a speed of 1 to 25 cm / sec.

The corona discharge electrode 50 reciprocates in the transverse direction several times near the surface of the installation panel 1.

On the surface of the corona discharge-treated installation panel 1, the carbon and hydrogen bonds of the polypropylene molecules are partially destroyed, and the molecules are ionized or oxidized to be activated.

Therefore, when the skin or the like is adhered to the surface of the corona discharge-treated mounting panel 1, the surface modification effect such as the adhesion is improved.

In addition, in this embodiment, since the whole discharge tip part 52 is formed in the spherical curved surface S, corona discharge generate | occur | produces uniformly, without concentrating to one point.

In addition, since the corona discharge is generated even when the interval between the corona discharge electrode 50 and the counter electrode 63 is relatively large, the present invention method is also applied to a molded article having a three-dimensional shape in which a practical effect is not recognized by the corona discharge treatment. I can do it

In addition, since a large number of hemispherical protrusions 53 are formed at the discharging tip 52 of the corona discharge electrode 50 of this embodiment, corona discharge occurs in all directions, and the discharge reach distance is also long.

Therefore, the corona discharge electrode 50 of this embodiment can fully obtain the discharge treatment effect even if the movement speed of the corona discharge electrode 50 is increased, and has a great effect in improving the productivity.

In addition, unlike the plasma treatment, the corona discharge treatment of the present embodiment does not require a vacuum chamber, a vacuum pump, a piping system, a carrier gas, and the like, so that the process can be automated.

The second embodiment will now be described. FIG. 8 shows a side protection support for a vehicle (hereinafter simply referred to as a pedestal) surface treated by the present embodiment 81 and a corona for corona discharge treatment of the pedestal 81. FIG. The corona discharge electrode 82 held by the front-end | tip of the Z-axis arm 43 of a discharge processing apparatus is shown.

The pedestal 81 is obtained by extruding EPOM, and a tetra-film consisting of a polyvinyl fluoride-polyester-vinyl chloride three-layer film is adhered to the bottom of the EPOM to form a pedestal product.

The electrode 82 is formed of stainless steel and has a rod-shaped gripping portion 83 having a diameter of about 2 mm and a discharge electrode 84 as a rod-shaped discharge portion having the same diameter as the gripping portion 83 at its tip. Consists of. The isoelectric discharge electrode 84 is bent to have a shape substantially the same as that of the cross section of the pedestal 81. Therefore, by using the electrode 82, it is possible to perform a uniform corona discharge treatment on each surface of the pedestal 81.

The pedestal 51 was mounted on the net 74 in the cleaning tank 71 used in the first embodiment, left for 30 seconds, the surface was washed with trichloroethane vapor, and the pedestal 81 was heated and dried. Trichloroethane attached to the surface was evaporated.

Thereafter, the corona discharge treatment on the surface of the pedestal 81 was performed in the same manner as in the first embodiment using the corona discharge treatment device provided with the rod-shaped discharge electrode 84.

Since the discharge electrode 84 of the present embodiment is formed by bending an elongated rod-shaped electrode into a shape substantially the same as the cross-sectional shape of the pedestal 81, it is possible to uniformly corona discharge the respective surfaces of the pedestal 81, and at the same time, the discharge reach distance. Is also long.

Therefore, the corona discharge electrode 82 of this embodiment is the same as the case of the first embodiment, and even if the movement speed thereof is increased, a sufficient discharge treatment effect can be obtained, and it has a great effect on productivity improvement.

In addition, this invention is not limited to the said Example, For example, it can also be embodied as shown below.

(1) The corona discharge electrode is not limited to the spherical or rod-shaped one, and it is also possible to use a cross-sectional electrode, a pin electrode, or the like depending on the shape of the polyolefin-based molding.

(2) The apparatus is not limited to the apparatus of the present embodiment, and an industrial robot or the like may be used.

(3) The polyolefin-based molding is not limited to the injection molding of the first embodiment or the extrusion molding of the second embodiment, and the moldings obtained by various molding methods such as blow molding and transfer molding are also subject to the present invention.

As described above, according to the present invention, the surface of the polyolefin-based molding is washed with an organic solvent to make the surface easy to be modified, and then the shape of the discharge portion is suitable for the surface shape of the polyolefin-based molding such as sphere, rod, or cotton. The corona discharge treatment is performed by using.

Therefore, the invention exhibits an excellent effect of uniformly and quickly modifying the surface of a polyolefin-based molding to which paint, printing ink or adhesive is to be applied.

Claims (2)

When the corona discharge electrode having the shape of the entire rear portion of the polyolefin-based molded article having the three-dimensional shape with the organic solvent is spherical, rod or face is generated corona discharge in the vicinity of the molded article, the corona discharge electrode is relatively formed according to the surface shape of the molded article. A method of surface treatment of a polyolefin-based molded product, characterized by moving. The surface treatment method according to claim 1, wherein the organic solvent has a solubility parameter that is the same as or close to that of the polyolefin.

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