TWI601618B - Method of corona treatment and method for manufacturing polarizing plate - Google Patents

Description

Corona treatment method and method for manufacturing polarizing plate

The present invention relates to a method of performing corona treatment on the surface of a film-like corona treated article.

Patent Documents 1 and 2 describe that the surface of a polarizing film or the like is subjected to corona treatment to activate the surface. The corona treatment is usually performed by applying a high frequency/high voltage output provided by a high frequency power source between a discharge electrode and a grounding roll provided in the corona treatment device to generate a corona discharge under the corona discharge. The film (such as a corona-treated material) such as a polarizing film is passed through.

However, if the corona treatment is applied for a long period of time, there is a problem that the crystal foreign matter adheres to the film (corona treated material) to cause a decrease in yield.

On the other hand, it is known that corona discharge causes generation of ozone and nitrogen oxides (NOx) (for example, refer to Patent Document 3). In Patent Document 3, the production of ozone and nitrogen oxides (NOx) is reduced by using a corona treatment device having a predetermined structure.

However, the corona treatment device described in Patent Document 3 is not necessarily sufficiently satisfactory in suppressing the adhesion of the crystal foreign matter during the long-term corona treatment. Further, Patent Document 3 has a problem that the corona treatment device must have a predetermined structure, and the corona treatment cannot be easily performed.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2005-213314

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2009-8860

[Patent Document 3] Japanese Patent No. 4194766

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

In order to solve the above problems, the inventors of the present invention have repeatedly conducted intensive studies and found the following findings.

That is, as a result of analyzing the crystal foreign matter adhering to the corona-treated film (corona treated material), it was found that the crystal foreign matter was oxalic acid, oxalate, ammonium oxalate, aluminum nitrate, ammonium nitrate or the like.

The inventors of the present invention have repeatedly reviewed the sources of such crystalline foreign substances. As a result, it was found that the crystal foreign matter was accumulated in the corona treatment device as it was progressed by the corona discharge, and was dropped and adhered to the film (corona treated material). Then, based on this finding, it is found that the corona treatment device is disposed in a specific direction in the opening of the electrode cover provided in the corona treatment device, and the accumulation in the corona treatment can be suppressed. The crystal foreign matter of the device is dropped and adhered to the film (corona treated material), thus completing the present invention.

That is, the corona treatment method of the present invention is constituted by the following constitution.

(1) A corona treatment method in which a corona discharge is generated between a discharge electrode and an earth roll provided in a corona treatment device, and a corona discharge is performed via a ground roller under the corona discharge Passing through the object, performing a corona treatment on the surface of the corona-treated material, the electricity The halo processing apparatus further includes an electrode cover that covers the discharge electrode and has an opening on the ground roller side, and the corona treatment device is disposed such that the opening of the electrode sleeve faces in the lateral direction or upward.

(2) The corona treatment method according to (1) above, wherein the corona treatment device is formed of a corrosion-resistant member.

(3) The corona treatment method according to (1) or (2) above, wherein the surface of the corona treatment device is subjected to a corrosion resistance treatment.

(4) The corona treatment method according to any one of (1) to (3), wherein the electrode sheath is formed of a transparent member.

(5) The corona treatment method according to any one of (1) to (4), wherein the film-like corona-treated material is at least one selected from the group consisting of an optical film and a protective film.

(6) The corona treatment method according to any one of (1) to (5), wherein the film-like corona-treated material has a length of 10,000 m or more.

In addition, the "grounding roller" of the present invention may have a function of causing a corona discharge to be generated between the discharge electrode and a corona-like corona treatment to be passed through the corona discharge. Or a back roll or the like.

The concept of the "film shape" of the present invention is not limited to a film shape, and it may be in the form of a film or a sheet as long as the effects of the present invention are not impaired.

The invention of the other aspect is a method for performing a corona treatment on a surface of a film, comprising: a step of generating a corona discharge between the discharge electrode and the ground roller; and moving the film on the ground roller under the corona discharge step, The discharge electrode is covered with an electrode sleeve, and the electrode sleeve has an opening on the ground roller side, and the opening of the electrode sleeve faces in the lateral direction, obliquely upward or upward.

Here, it is preferable that at least one of the discharge electrode, the grounding roller, and the electrode sleeve has a corrosion-resistant material.

Further, preferably, the surface of at least one of the discharge electrode, the grounding roller, and the electrode sleeve is subjected to a corrosion resistance treatment.

Further, it is preferable that the gas system in the space surrounded by the electrode sleeve is exhausted via an exhaust pipe having a corrosion-resistant material or a surface of the exhaust pipe subjected to corrosion resistance treatment.

Further, preferably, the discharge electrode is held by an electrode holder, and the electrode holder has a corrosion-resistant material or the surface of the electrode holder is subjected to a corrosion-resistant treatment.

Further, the electrode sleeve is preferably transparent.

Further, the film is preferably at least one selected from the group consisting of an optical film and a protective film.

Further, the length of the film is preferably 10,000 meters or more.

According to the present invention, it is possible to suppress the crystal foreign matter accumulated in the corona treatment device from falling and adhering to the film (corona treated material), so that the corona treatment can be stably performed for a long period of time. Further, a corona treatment device having a general configuration can be employed, so that corona treatment can be easily performed.

Hereinafter, an embodiment of the corona treatment method of the present invention will be described in detail with reference to Figs. 1 to 4 . The corona treatment method of this embodiment is used The corona treatment device 1 shown in Fig. 1 is implemented.

The corona treatment apparatus 1 includes a discharge electrode 2, a ground roller 3 disposed opposite the discharge electrode 2, an electrode sheath 4 covering the discharge electrode 2, an electrode holder 5 holding the discharge electrode 2, and a grounding electrode located at the electrode sleeve 4. One end face 4a on the side of the roller 3 is the exhaust pipe 6 on the other end face 4b side on the opposite side.

The discharge electrode 2 has a substantially rod shape, and its front end portion 2a is located on the inner side of the electrode sleeve 4 than the end surface 4a of the electrode sleeve 4, and the rear end portion 2b is held by the electrode holder 5. Further, the shape of the discharge electrode 2 is not limited to a rod shape, and may be other shapes such as a needle shape, a plate shape, or a column shape.

The ground roller 3 is disposed at a predetermined interval from the tip end portion 2a of the discharge electrode 2 while being grounded, and is disposed to face the discharge electrode 2. The ground roller 3 is connected to a turning drive means such as a motor (not shown), and can be configured to be rotated at a predetermined peripheral speed.

The electrode sleeve 4 has an opening portion 4c that is open at one end surface 4a of the ground roller 3 side. Further, the electrode sleeve 4 has a pair of side faces 4d, 4d. The pair of side faces 4d, 4d extend slightly parallel to each other from one end face 4a toward the other end face 4b.

A portion of the periphery of the exhaust pipe 6 passes through the space surrounded by the electrode sleeve 4, and an exhaust pipe outlet (not shown) is connected to a suction means such as a vacuum pump. Thereby, the gas in the space surrounded by the electrode sheath 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 device 1 via the exhaust pipe 6. The air volume of the exhaust pipe outlet of the exhaust pipe 6 is preferably 0.1 m ³ /sec or more in the exhaust gas which is surely subjected to ozone.

The corona treatment method of the present embodiment is performed by the corona treatment apparatus 1 described above, and a high-frequency high-voltage output supplied from a high-frequency power source (not shown) is applied between the discharge electrode 2 and the ground roller 3 to Corona discharge is generated, and the film-like corona-treated material 10 is passed through the ground roller 3 under corona discharge, whereby the surface of the corona-treated material 10 is subjected to a corona treatment. That is, under corona discharge, the film is moved on the aforementioned grounding roller, whereby the surface of the film is subjected to corona treatment.

The corona treatment strength is not particularly limited as long as it is a desired strength in response to the film (corona treated material) 10, but is usually about 200 to 2000 W. When the corona treatment strength is too low, it is difficult to obtain a corona discharge in which the film (corona treated material) 10 is completely wide and stable, and when it is too high, the heat resistance of the film (corona treated material) 10 is high. However, there is a difference, but the generated heat tends to cause wrinkles and the like in the film (corona treated material) 10, which is not preferable.

Here, in the corona treatment method of the present embodiment, as shown in FIGS. 2(a) to 4(c), the corona treatment device 1 can be disposed in the opening portion 4c of the electrode sheath 4 in the lateral direction or the upward direction. That is, the opening portion 4c of the electrode sheath 4 faces the lateral direction, the obliquely upper side, or the upper side. Thereby, it is possible to suppress the crystal foreign matter accumulated in the corona treatment device 1 from falling and adhering to the film (corona treated material) 10, and it is possible to perform the corona treatment for a long period of time. On the other hand, as shown in FIGS. 3( a ) and 3 ( b ), the corona treatment device 1 is disposed so that the opening 4 c of the electrode sheath 4 is disposed obliquely below or even below the lateral direction, and is accumulated in the corona treatment device 1 . The crystal foreign matter is dropped to the film (corona treated).

On the other hand, a general corona treatment device constitutes an electrode holder 5 or a row Most of the members such as the gas pipe 6 are made of aluminum, and many of the crystal foreign materials tend to adhere to members made of aluminum. Therefore, the corona treatment apparatus 1 of the present embodiment (for example, at least one of a discharge electrode, a grounding roller, an electrode sleeve, an electrode holder, and an exhaust pipe) is preferably made of a member other than aluminum, and more preferably is corrosion-resistant. Constructed by sexual components. The corrosion resistant member may, for example, be ceramic or stainless steel (SUS). Further, the corona treatment apparatus 1 itself is formed of a corrosion-resistant member which is changed into a corona treatment apparatus 1 (for example, at least one of a discharge electrode, a grounding roller, an electrode sleeve, an electrode holder, and an exhaust pipe) by a corrosion-resistant member. The same effect can be obtained by coating or by subjecting the surface to corrosion resistance. The corrosion resistant treatment may, for example, be an alumite treatment or the like. The application of the above-described corrosion-resistant member or the corrosion-resistant treatment can be applied to the entire corona treatment apparatus 1, and can be applied to a member or a region where the crystal foreign matter easily adheres to the corona treatment device 1.

Further, the electrode sheath 4 is preferably made of a transparent member. As a result, the electrode sheath 4 becomes transparent, so that the state of the discharge electrode 2, the electrode holder 5, and the like can be visually confirmed through the electrode sheath 4. The transparent member may, for example, be an acrylic resin. Transparent means transparent to visible light (for example 390 to 750 nm).

The inner side of the side surface 4d of the electrode sheath 4 is preferably formed in a shape that does not have a groove or irregularities that easily accumulate crystal foreign matter.

The film (corona treated material) 10 subjected to corona treatment by the corona treatment device 1 can be a desired film shape requiring corona treatment, and is not particularly limited, and may be, for example, an optical film such as a polarizing film. A protective film of an optical film, a film of an adhesive layer or an adhesive layer, or the like. The polarizing film may, for example, be one in which a dichroic dye is oriented and adsorbed on a polyvinyl alcohol-based film, and the protective film may, for example, be as follows. A cellulose acetate resin film, a cycloolefin resin film, or the like of cellulose triacetate or cellulose diacetate.

The length of the film (corona treated material) 10 (hereinafter referred to as "treatment amount") is preferably 10,000 meters or more, more preferably 30,000 meters or more, and more preferably 40,000 meters to 60,000 meters. ruler. When the corona treatment of the conventional method is performed on such a treatment amount, there is a tendency that crystal foreign matter tends to adhere to the film (corona treated material) 10 . According to the corona treatment method of the present embodiment which can perform corona treatment for a long period of time, the corona treatment can be stably performed for the above treatment amount. Further, the film (corona treated material) 10 having the above-described treatment amount may be taken out from one raw material roll which is wound into a roll shape from a long film (corona treated material), or may be each A plurality of films (corona treated) of a predetermined throughput are connected.

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

Next, an embodiment in which the polarizing film and the protective film are used as the film (corona treated material) 10 will be described with reference to Fig. 4, and an embodiment of the corona treatment of the present invention will be described in detail.

As shown in the same figure, first, the two corona treatment apparatuses 1, 1 are placed at predetermined positions in the lateral direction of the opening 4c of the electrode sheath 4.

Next, the polarizing film 11 and the protective film 12 are conveyed in the directions of arrows A and B via corona treatment 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 may be in contact with the corona-treated front rollers 15a and 15b.

Then, a high-frequency high-voltage output supplied from a high-frequency power source (not shown) is applied between the discharge electrode 2 and the ground roller 3, and a corona discharge is generated between the two, and under the corona discharge, via the ground roller 3 The polarizing film 11 and the protective film 12 are passed.

By this, the surface of each of the polarizing film 11 and the protective film 12 can be subjected to a corona treatment, and since the corona treatment device 1 is disposed in the lateral direction of the opening 4c of the electrode can 4, the crystal accumulated in the corona treatment device 1 can be suppressed. The foreign matter is dropped and adheres to the polarizing film 11 and the protective film 12, so that the corona treatment can be performed stably for a long period of time.

On the other hand, in order to reduce the cost, it is preferable to carry a cheap film as a lead film before transporting the polarizing film 11 and the protective film 12, and thereafter, the polarizing film 11 and the protective film 12 are carried. At this time, it is preferable that corona discharge is not generated when the guide film is conveyed, and corona discharge is generated when the polarizing film 11 and the protective film 12 pass through the ground roller 3.

The polarizing film 11 and the protective film 12 after the corona treatment are conveyed in the directions of arrows C and D through the corona-treated guide rolls 16a and 16b, respectively. Here, if the surfaces of the polarizing film 11 and the protective film 12 activated by the corona treatment are in contact with the corona-treated guide rolls 16a, 16b, the corona-treated guide rolls 16a, 16b are contaminated. tendency. The reason for this is that oxalic acid or the like generated by corona treatment is present on the surfaces of the polarizing film 11 and the protective film 12 after the corona treatment, and these are attached to the corona-treated guide rolls 16a and 16b. Therefore, in the present embodiment, the polarizing film 11 and the protective film 12 after the corona treatment are conveyed so that the back surface opposite to the surface activated by the corona treatment comes into contact with the corona-treated guide rolls 16a and 16b.

Then, the surfaces activated by the corona treatment are bonded to each other by the pair of left and right bonding rolls 17a, 17b, and are taken as the polarizing plate 13 in the direction of the arrow E. In addition, the layer structure of the polarizing plate 13 is configured by laminating the protective film 12 on the surface of the polarizing film 11, and the protective film 12 may be bonded to the back surface of the polarizing film 11 to form a three-layer structure.

Further, the bonding of the polarizing film 11 and the protective film 12 can be carried out, for example, by using an adhesive, an adhesive (pressure-sensitive adhesive), or the like, and is not particularly limited.

The following examples are given to illustrate the invention in detail, but the invention is not limited to the following examples.

(Example)

The surface of the film (corona treated material) 10 was subjected to corona treatment using the corona treatment device 1 shown in Fig. 1 described above. Then, whether or not the crystal foreign matter adhered to the film (corona treated material) 10 was visually observed and evaluated. The configuration of the corona treatment device 1 to be used, the film (corona treated material) 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 surface treated with alumite treatment (corrosion resistant treatment)

. Electrode sleeve 4: made of transparent acrylic resin

. The direction of the opening 4c of the electrode sleeve 4: obliquely upward (refer to Fig. 2(b)) (film (corona treated) 10 and corona treatment conditions)

. Film (corona treated material) 10: a polarizing film, a cycloolefin film, and a cellulose triacetate film each having a predetermined treatment amount are connected

. Corona treatment strength: 600W

. Processing capacity: 49654m

[Comparative example]

The surface of the film (corona treated material) 10 was corona as in the above-described embodiment except that the direction of the opening 4c of the electrode sheath 4 was downward (refer to FIG. 3(b)) and the treatment amount was 49,747 m. The treatment was carried out by visually observing whether or not a crystal foreign matter adhered to the film (corona treated material) 10 for evaluation. The results are shown in Table 1.

As is apparent from Table 1, in the embodiment in which the direction of the opening 4c of the electrode sheath 4 is obliquely upward, a long-term and stable corona treatment can be performed in a comparative example in which the direction of the opening 4c is downward.

1‧‧‧Corona treatment device

2‧‧‧Discharge electrode

2a‧‧‧ front end

2b‧‧‧ back end

3‧‧‧ Grounding roller

4‧‧‧electrode sleeve

4a‧‧‧One end

4b‧‧‧Other end face

4c‧‧‧ openings

4d‧‧‧ side

5‧‧‧electrode clip

6‧‧‧Exhaust pipe

10‧‧‧film (corona treated)

11‧‧‧ polarizing film

12‧‧‧Protective film

13‧‧‧Polar plate

15a, 15b‧‧‧Corona treatment front roller

16a, 16b‧‧‧Corona treatment guide roller

17a, 17b‧‧‧ affixing rolls

Fig. 1 is a schematic view showing a corona treatment apparatus according to an embodiment of the present invention.

Fig. 2 (a) to (c) are views showing the arrangement state of the corona treatment apparatus shown in Fig. 1.

Fig. 3 (a) and (b) are views showing the arrangement state of the corona treatment apparatus shown in Fig. 1.

Fig. 4 is a view showing a corona treatment method according to an embodiment of the present invention.

1‧‧‧Corona treatment device

2‧‧‧Discharge electrode

2a‧‧‧ front end

2b‧‧‧ back end

3‧‧‧ Grounding roller

4‧‧‧electrode sleeve

4a‧‧‧One end

4b‧‧‧Other end face

4c‧‧‧ openings

4d‧‧‧ side

5‧‧‧electrode clip

6‧‧‧Exhaust pipe

10‧‧‧film (corona treated)

Claims (10)

A corona treatment method for performing a corona treatment on a surface of a film, comprising: a step of generating a corona discharge between a discharge electrode and a ground roller; and performing a corona discharge on the ground roller under the corona discharge, a step of performing a corona treatment on the surface of the polarizing film; and a step of transporting the polarizing film after the corona treatment so that the back surface opposite to the surface of the polarizing film activated by the corona treatment is in contact with the guide roller And a step of bonding the aforementioned surface of the polarizing film activated by corona treatment to the protective film by using an adhesive or an adhesive; the discharge electrode is covered with an electrode sleeve, and the electrode sleeve has an opening on the ground roller side In the portion, the opening of the electrode sleeve is inclined upward or upward. A corona treatment method for performing a corona treatment on a surface of a film, comprising: a step of generating a corona discharge between the discharge electrode and the ground roller; and moving the protective film on the ground roller under the corona discharge, a step of performing a corona treatment on the surface of the protective film; and a step of transporting the protective film after the corona treatment so that the back surface opposite to the surface of the protective film activated by the corona treatment is in contact with the guide roller And a step of bonding the aforementioned surface of the protective film activated by corona treatment to the polarizing film by using an adhesive or an adhesive; the discharge electrode is covered with an electrode sleeve, and the electrode sleeve has an opening on the ground roller side unit, The opening of the electrode sleeve is inclined upward or upward. A corona treatment method for performing a corona treatment on a surface of a film, comprising: a step of generating a corona discharge between a discharge electrode and a ground roller; and performing a corona discharge on the ground roller under the corona discharge, a step of performing a corona treatment on the surface of the polarizing film; a step of generating a corona discharge between the discharge electrode and the grounding roller; and moving the protective film on the grounding roller under the corona discharge to the surface of the protective film a step of performing a corona treatment; a step of transporting the polarizing film after the corona treatment in such a manner that a back surface opposite to the surface of the polarizing film activated by the corona treatment is in contact with the guide roller; a step of carrying the corona-treated protective film in a manner in which the opposite surface of the protective film activated by the corona treatment is in contact with the guide roller, and an adhesive or an adhesive is used by corona treatment a step of abutting the aforementioned surface of the polarizing film activated and the aforementioned surface of the protective film activated by corona treatment, wherein the discharge electrode is an electrode Cover, the sleeve having an opening portion at an electrode the ground roller side, the electrode opening sleeve portion based obliquely upward, or over. The corona treatment method according to any one of claims 1 to 3, wherein the discharge electrode, the grounding roller, and the electric At least one of the pole sets has a corrosion resistant member. The corona treatment method according to any one of claims 1 to 3, wherein the surface of at least one of the discharge electrode, the grounding roller, and the electrode sleeve is subjected to corrosion resistance treatment. The corona treatment method according to any one of claims 1 to 3, wherein the gas system in the space surrounded by the electrode sleeve is exhausted via an exhaust pipe having a corrosion resistant member or The surface of the aforementioned exhaust pipe is subjected to corrosion resistance treatment. The corona treatment method according to any one of claims 1 to 3, wherein the discharge electrode is held by an electrode holder, the electrode holder has a corrosion-resistant member or the surface of the electrode holder is corrosion-resistant Processor. The corona treatment method according to any one of claims 1 to 3, wherein the electrode sleeve is transparent. The corona treatment method according to any one of claims 1 to 3, wherein the length of the polarizing film and the protective film are each 10,000 meters or more. A method of producing a polarizing plate, which comprises the corona treatment method according to any one of claims 1 to 9.