JP5787306B2 - Corona treatment method - Google Patents

Description

  The present invention relates to a method for corona-treating the surface of a film-like object to be corona-treated.

Patent Documents 1 and 2 describe that the surface of a polarizing film or the like is activated by corona treatment. Corona treatment usually generates a corona discharge by applying a high-frequency / high-voltage output supplied by a high-frequency power source between a discharge electrode provided in the corona treatment device and an earth roll, and a polarizing film under this corona discharge It is performed by passing a processed object such as corona.
However, when the corona treatment is performed for a long period of time, there is a problem that the crystal foreign matter adheres to the corona-treated material and the yield decreases.

  On the other hand, it is known that ozone and nitrogen oxides (NOx) are generated by corona discharge (see, for example, Patent Document 3). In patent document 3, the generation amount of ozone and nitrogen oxide (NOx) is reduced by using a corona treatment apparatus having a predetermined structure.

  However, the corona treatment apparatus described in Patent Document 3 is not always satisfactory in that it suppresses the adhesion of crystalline foreign matters when the above-described corona treatment is performed over a long period of time. Further, Patent Document 3 has a problem that the corona treatment cannot be easily performed in that the corona treatment device needs to have a predetermined structure.

JP 2005-213314 A JP 2009-8860 A Japanese Patent No. 4194766

  An object of the present invention is to provide a method capable of performing corona treatment stably over a long period of time.

  As a result of intensive studies to solve the above problems, the present inventors have found the following findings. That is, as a result of analyzing the crystalline foreign matter adhering to the corona-treated material, the crystalline foreign matter was oxalic acid, oxalate, ammonium oxalate, aluminum nitrate, ammonium nitrate, and the like.

  The present inventors have repeatedly investigated the origin of these crystalline foreign substances. As a result, it was found that these crystalline foreign substances were accumulated in the corona treatment apparatus as corona discharge was performed, and dropped and adhered to the corona treatment object. And as a result of further earnest research based on this knowledge, if the corona treatment device is arranged so that the opening of the electrode cover provided in the corona treatment device is in a specific direction, the crystalline foreign matter accumulated in the corona treatment device Has been found to be able to suppress falling and adhering to the corona-treated material, and the present invention has been completed.

That is, the corona treatment method of the present invention has the following configuration.
(1) Corona discharge is generated between a discharge electrode provided in a corona treatment apparatus and an earth roll, and a film-like object to be treated is passed through the earth roll under the corona discharge, and the object to be corona treated is passed through. The corona treatment device further includes an electrode cover that covers the discharge electrode and has an opening on the ground roll side, and the opening of the electrode cover is laterally or upward. The corona treatment method is characterized by disposing the corona treatment device.
(2) The corona treatment method according to (1), wherein the corona treatment device is formed of a corrosion-resistant member.
(3) The corona treatment method according to (1) or (2), wherein the surface of the corona treatment device is subjected to corrosion resistance treatment.
(4) The corona treatment method according to any one of (1) to (3), wherein the electrode cover is made of a transparent member.
(5) The corona treatment method according to any one of (1) to (4), wherein the film-like corona-treated product is at least one selected from an optical film and a protective film.
(6) The corona treatment method according to any one of (1) to (5), wherein a length of the film-like corona treatment product is 10,000 m or more.

The “earth roll” in the present invention may have any function as long as it has a function of generating corona discharge between the discharge electrodes and passing the film-like corona-treated material under the corona discharge. What is called a roll, a back roll, etc. are also included.
The “film shape” in the present invention is not limited to a film shape, and is a concept including a film shape or a sheet shape as long as the effects of the present invention are not impaired.

  According to the present invention, the crystalline foreign matter accumulated in the corona treatment apparatus can be prevented from dropping and adhering to the corona treatment object, and therefore the corona treatment can be performed stably over a long period of time. effective. And since the corona treatment apparatus which has a general structure is employable, a corona treatment can be performed easily.

It is a schematic explanatory drawing which shows the corona treatment apparatus concerning one Embodiment of this invention. (A)-(c) is a schematic explanatory drawing explaining the arrangement | positioning state of the corona treatment apparatus shown in FIG. (A), (b) is a schematic explanatory drawing explaining the arrangement | positioning state of the corona treatment apparatus shown in FIG. It is a schematic explanatory drawing which shows the corona treatment method concerning one Embodiment of this invention.

  Hereinafter, an embodiment of a corona treatment method according to the present invention will be described in detail with reference to FIGS. The corona treatment method of this embodiment is performed using the corona treatment apparatus 1 shown in FIG.

  The corona treatment apparatus 1 includes a discharge electrode 2, an earth roll 3 disposed opposite to the discharge electrode 2, an electrode cover 4 covering the discharge electrode 2, and an electrode holder holding the discharge electrode 2. 5 and an exhaust pipe 6 located on the other end face 4b side opposite to the one end face 4a located on the earth roll 3 side of the electrode cover 4.

  The discharge electrode 2 has a substantially rod shape, and a tip end portion 2 a thereof is positioned inward of the electrode cover 4 with respect to one end face 4 a of the electrode cover 4, and a rear end portion 2 b is held by the electrode holder 5. The shape of the discharge electrode 2 is not limited to a substantially rod shape as long as discharge is possible, and may be another shape such as a needle shape, a plate shape, or a column shape.

  The ground roll 3 is grounded, and is disposed opposite to the discharge electrode 2 with a predetermined interval between the tip end 2 a of the discharge electrode 2. The earth roll 3 is connected to a rotation driving means such as a motor (not shown), and is configured to be rotatable at a predetermined peripheral speed.

  The electrode cover 4 has an opening 4c that opens to one end face 4a located on the ground roll 3 side. The electrode cover 4 has a pair of side surfaces 4d and 4d. The pair of side surfaces 4d, 4d extend from the one end surface 4a toward the other end surface 4b so as to be substantially parallel to each other.

The exhaust pipe 6 communicates with a part of its outer periphery surrounded by the electrode cover 4, and an exhaust pipe outlet (not shown) is connected to suction means such as a vacuum pump. Thereby, the gas in the space surrounded by the electrode cover 4 can be sucked through the exhaust pipe 6 and exhausted to the outside of the corona treatment apparatus 1. Therefore, ozone generated by the corona treatment can be exhausted to the outside of the corona treatment apparatus 1 through the exhaust pipe 6. The air volume at the exhaust pipe outlet of the exhaust pipe 6 is preferably 0.1 m ³ / second or more in order to reliably exhaust ozone.

  The corona treatment method of the present embodiment performed using the above-described corona treatment apparatus 1 applies a high frequency / high voltage output supplied by a high frequency power source (not shown) between the discharge electrode 2 and the earth roll 3. In this method, a corona discharge is generated between them, and the film-like processed object 10 is passed through the earth roll 3 under the corona discharge, whereby the surface of the processed object 10 is corona-treated. .

  As the corona treatment strength, a desired strength may be adopted according to the corona treatment object 10 and is not particularly limited, but is usually about 200 to 2000 W. If the corona treatment strength is too low, it tends to be difficult to obtain a stable corona discharge over the entire width of the corona treated product 10, and if it is too high, it occurs although there is a difference depending on the heat resistance characteristics of the corona treated product 10. This is not preferable because wrinkles and the like tend to occur in the object to be corona treated 10 due to heat.

  Here, in the corona treatment method of the present embodiment, as shown in FIGS. 2A to 2C, the corona treatment apparatus 1 is arranged so that the opening 4c of the electrode cover 4 described above is laterally or upward. . Thereby, it can suppress that the crystalline foreign material accumulate | stored in the corona treatment apparatus 1 falls and adheres to the to-be-corona-treated object 10, and can perform a corona treatment stably over a long period of time. On the other hand, as shown in FIGS. 3A and 3B, when the corona treatment device 1 is disposed so that the opening 4c of the electrode cover 4 is inclined downward or downward rather than laterally, the corona treatment device 1 is arranged. The accumulated crystalline foreign matter falls on the corona-treated object 10.

  On the other hand, a general corona treatment apparatus often employs aluminum as a member constituting an electrode holder, an exhaust pipe, or the like, but a large amount of crystalline foreign matter tends to adhere to a member composed of aluminum. Therefore, the corona treatment apparatus 1 according to the present embodiment is preferably composed of a member other than aluminum, and more preferably composed of a corrosion-resistant member. Examples of the corrosion resistant member include ceramics and stainless steel (SUS). Further, instead of configuring the corona treatment apparatus 1 itself with a corrosion-resistant member, the same effect can be obtained by covering the surface of the corona treatment apparatus 1 with a corrosion-resistant member or subjecting the surface to a corrosion-resistant treatment. it can. Examples of the corrosion resistance treatment include alumite treatment. The application of the corrosion-resistant member and the corrosion-resistant treatment described above may be applied to the entire corona treatment apparatus 1 or may be applied to a member or a region of the corona treatment apparatus 1 where crystalline foreign matters are likely to adhere. Good.

  Moreover, it is preferable to comprise the electrode cover 4 with a transparent member. Thereby, since the electrode cover 4 becomes transparent, the states of the discharge electrode 2, the electrode holder 5, and the like can be visually confirmed through the electrode cover 4. As a transparent member, acrylic resin etc. are mentioned, for example. The inner side of the side surface 4d of the electrode cover 4 is preferably configured in a shape without grooves or irregularities in which crystalline foreign matters are easily accumulated.

  As the corona-treated object 10 to be corona-treated by the corona treatment apparatus 1, a desired film-like material that requires corona treatment can be adopted, and is not particularly limited. For example, an optical film such as a polarizing film And a protective film for protecting the optical film, a film provided with an adhesive layer and an adhesive layer, and the like. Examples of the polarizing film include those obtained by adsorbing and orienting a dichroic dye on a polyvinyl alcohol film, and examples of the protective film include acetylcellulose-based resin films such as triacetylcellulose and diacetylcellulose, and cycloolefin-based films. Resin film etc. are mentioned.

  The length of the corona treated object 10 (hereinafter referred to as “treatment amount”) is preferably 10,000 m or more, more preferably 30,000 m or more, and 40,000 m to 60,000 m. More preferably. When the conventional corona treatment is performed on such a treatment amount, the crystalline foreign matter tends to adhere to the treated object 10. According to the corona treatment method of this embodiment capable of performing corona treatment stably over a long period of time, corona treatment can be performed stably even for the above-described treatment amount. In addition, the to-be-corona-treated object 10 which has the processing amount mentioned above may be drawn out from one original fabric roll formed by winding a long to-be-treated object to be rolled, A plurality of corona processed products having a predetermined processing amount may be added.

  The thickness of the corona-treated material 10 is usually about 10 to 300 μm, and the width of the corona-treated material 10 is usually about 300 to 2500 mm, but is not limited thereto.

  Next, a case where a polarizing film and a protective film are used as the object to be treated 10 will be described as an example, and an embodiment in which the corona treatment of the present invention is performed on these surfaces will be described in detail with reference to FIG. To do.

  As shown in the figure, first, the two corona treatment devices 1 and 1 are arranged at predetermined positions so that the opening 4c of the electrode cover 4 is oriented horizontally.

  Next, the polarizing film 11 and the protective film 12 are conveyed in the directions of arrows A and B via the pre-corona-treated guide rolls 15a and 15b, respectively. At this time, the polarizing film 11 and the protective film 12 are conveyed so that the respective surfaces are in contact with the pre-corona-treated guide rolls 15a and 15b.

  A high frequency / high voltage output supplied from a high frequency power source (not shown) is applied between the discharge electrode 2 and the earth roll 3 to generate a corona discharge between them, and the earth roll under the corona discharge. The polarizing film 11 and the protective film 12 are passed through 3. Thereby, while each surface of the polarizing film 11 and the protective film 12 can be corona-treated, since the corona treatment apparatus 1 is arrange | positioned so that the opening part 4c of the electrode cover 4 may turn sideways, a corona treatment apparatus 1 can be prevented from falling and adhering to the polarizing film 11 and the protective film 12, and therefore corona treatment can be performed stably over a long period of time.

  On the other hand, in order to reduce costs, it is preferable to transport an inexpensive film as a lead film before transporting the polarizing film 11 and the protective film 12 and then transport the polarizing film 11 and the protective film 12. At that time, it is preferable not to generate corona discharge during the lead film conveyance, but to generate corona discharge when the polarizing film 11 and the protective film 12 pass over the earth roll 3.

  The corona-treated polarizing film 11 and the protective film 12 are conveyed in the directions of arrows C and D via the corona-treated guide rolls 16a and 16b, respectively. Here, when the surfaces of the polarizing film 11 and the protective film 12 activated by the corona treatment contact the guide rolls 16a and 16b after the corona treatment, the guide rolls 16a and 16b after the corona treatment tend to be contaminated. The reason for this is that oxalic acid or the like produced by corona treatment is present on the surfaces of the polarizing film 11 and the protective film 12 after corona treatment, which adheres to the guide rolls 16a and 16b after corona treatment. It is guessed. Therefore, in this embodiment, the polarizing film 11 and the protective film 12 after corona treatment are conveyed so that the back surface opposite to the surface activated by the corona treatment is in contact with the guide rollers 16a and 16b after corona treatment.

  And the mutual surfaces activated by the corona treatment are bonded by a pair of left and right bonding rolls 17a and 17b, and taken in the direction of arrow E to obtain a polarizing plate 13. The layer configuration of the polarizing plate 13 is a two-layer configuration in which the protective film 12 is bonded to the surface of the polarizing film 11, but the protective film 12 is bonded to the back surface of the polarizing film 11 to have a three-layer configuration. It is good. Moreover, the bonding of the polarizing film 11 and the protective film 12 can be performed using, for example, an adhesive, a pressure-sensitive adhesive (pressure-sensitive pressure-sensitive adhesive), and the like, and is not particularly limited.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated in detail, this invention is not limited only to a following example.

  The corona treatment apparatus 1 shown in FIG. 1 was used to corona-treat the surface of the object to be treated 10. And the presence or absence of the crystalline foreign material adhering to the to-be-corona-treated object 10 was evaluated by visual observation. The structure of the corona treatment apparatus 1 used, the corona treatment object 10 and the corona treatment conditions are shown below, and the results are shown in Table 1.

(Configuration of corona treatment device 1)
-Electrode holder 5 and exhaust pipe 6: Aluminum whose surface is anodized (corrosion-resistant treatment)-Electrode cover 4: Transparent acrylic resin-Direction of opening 4c of electrode cover 4: diagonally upward (FIG. 2 (b) reference)

(Corona treated product 10 and corona treatment conditions)
-Corona-treated product 10: a polarizing film, a cycloolefin film and a triacetyl cellulose film each having a predetermined treatment amount- Corona treatment strength: 600W
・ Processing amount: 49654m

[Comparative example]
The surface of the object to be corona treated 10 is corona treated in the same manner as in the above embodiment except that the opening 4c of the electrode cover 4 is directed downward (see FIG. 3B) and the treatment amount is 49747m. The presence / absence of adhesion of crystalline foreign matter to the corona treated product 10 was evaluated by visual observation. The results are shown in Table 1.

  As is apparent from Table 1, the embodiment in which the direction of the opening 4c of the electrode cover 4 is obliquely upward can perform corona treatment stably over a longer period than the comparative example in which the direction of the opening 4c is downward. I can see that

DESCRIPTION OF SYMBOLS 1 Corona treatment apparatus 2 Discharge electrode 3 Ground roll 4 Electrode cover 4a One end surface 4b Other end surface 4c Opening part 4d Side surface 5 Electrode holder 6 Exhaust pipe 10 Corona-treated object 11 Polarizing film 12 Protective film 13 Polarizing plates 15a and 15b Before corona treatment Guide rolls 16a, 16b Guide rolls 17a, 17b after corona treatment

Claims (6)

A corona discharge is generated between the discharge electrode and the earth roll provided in the corona treatment device, and the film-like object to be treated is passed through the earth roll under the corona discharge, and the surface of the object to be corona treated is passed through. A method of corona treatment,
The corona treatment device further includes an electrode cover that covers the discharge electrode and has an opening on the ground roll side,
As the opening of the electrode cover is obliquely upper direction or upward, corona treatment method characterized by placing the corona treatment apparatus.   The corona treatment method according to claim 1, wherein the corona treatment device is made of a corrosion-resistant member.   The corona treatment method according to claim 1 or 2, wherein a surface of the corona treatment device is subjected to corrosion resistance treatment.   The corona treatment method according to claim 1, wherein the electrode cover is made of a transparent member.   The corona treatment method according to any one of claims 1 to 4, wherein the film-like object to be corona-treated is at least one selected from an optical film and a protective film.   The corona treatment method according to any one of claims 1 to 5, wherein a length of the film-like corona treatment product is 10,000 m or more.

Images