JP5006951B2 - Film surface treatment equipment - Google Patents

Description

  The present invention relates to an apparatus for surface treatment of a continuous film, for example, a film surface treatment apparatus suitable for a treatment for improving the adhesion of a protective film of a polarizing plate.

  For example, a polarizing plate is incorporated in a liquid crystal display device. The polarizing plate is obtained by bonding a protective film made of a resin film containing triacetate cellulose (TAC) as a main component to a polarizing film made of a resin film containing polyvinyl alcohol (PVA) as a main component using an adhesive. As the adhesive, water-based adhesives such as polyvinyl alcohol and polyether are used. PVA films have good adhesion to these adhesives, but TAC films do not have good adhesion. As a means for improving the adhesion of the TAC film, a saponification treatment is generally used. In the saponification treatment, the TAC film is immersed in a high-temperature, high-concentration alkaline solution. Therefore, problems of workability and waste liquid treatment have been pointed out.

  As an alternative technique, Patent Document 1 describes that a polymerizable monomer is coated on the surface of the protective film and irradiated with atmospheric pressure plasma before the bonding step. In the atmospheric pressure plasma irradiation apparatus, one roll electrode is accommodated in a sealed container, and a plurality of plate electrodes are arranged at intervals along the outer periphery of the roll electrode. The protective film coated with the polymerizable monomer is wound around the roll electrode. And discharge gas, such as nitrogen, is introduce | transduced in an airtight container, and it plasmifies between a roll electrode and each flat plate electrode. As a result, the polymerizable monomer is polymerized, the hydrophilicity of the protective film is increased, and the aqueous adhesive is easily adapted to the protective film.

  The plasma processing apparatus of Patent Document 2 has a pair of roll electrodes and a processing gas blowing nozzle. The blowing nozzle faces the gap between the roll electrodes. A continuous film is wound around a pair of roll electrodes, and plasma treatment is performed in the gap between the roll electrodes. A pair of roll electrodes rotate in synchronization with each other to convey a continuous film.

JP 2009-25604 A JP 2009-035724 A

  In the above-mentioned Patent Document 1, the roll electrode of the plasma irradiation apparatus is covered with a protective film, but the flat plate electrode is directly exposed to plasma. For this reason, dirt composed of a polymer of a polymerizable monomer or the like tends to adhere to the plate electrode. This dirt component causes particles and causes a decrease in yield.

On the other hand, in patent document 2, since the to-be-processed film covers both roll electrodes, there is little dirt of an electrode. However, in the electrode structure composed of a pair of roll electrodes, the effective discharge region is limited to the narrowest portion between the roll electrodes and the vicinity thereof. For this reason, it is conceivable that the plasma reaction does not proceed sufficiently, and the processing efficiency cannot be sufficiently secured, or unreacted reaction components remain on the surface of the film. When the reaction component is acrylic acid or the like, an odor is generated from the film if the reaction is not sufficient.
In view of the above circumstances, the present invention activates a reactive component such as a polymerizable monomer and plasma-treats a film to be treated such as a protective film for a polarizing plate while preventing the contamination of the electrode while reacting the reactive component. The purpose is to ensure sufficient and enhance treatment effects such as adhesion.

In order to solve the above problems, the present invention is a film surface treatment apparatus that activates a reaction component to react on the surface of the film to be treated while conveying a continuous film to be treated,
A main processing unit disposed relatively upstream in the transport direction; and a reactivation unit disposed relatively downstream in the transport direction;
The main processing part is arranged in parallel so as to form a main discharge space near atmospheric pressure between each other, and the transport direction from the main discharge space in the film to be processed, the first roll electrode and the second roll electrode And a nozzle that blows out a reaction gas containing the reaction component toward the main discharge space or the main discharge space, the film to be processed being wound around the first roll electrode, and the main discharge space The first roll electrode and the second roll electrode are rotated around their own axes and in the same direction, thereby being turned around the second roll electrode. The treated film is conveyed from the first roll electrode to the second roll electrode,
The reactivation unit includes a pair of rear electrodes in which a redischarge space near atmospheric pressure is formed between each other, and a gas supply unit that supplies a discharge generation gas that does not contain the reaction component between the rear electrodes. The film to be processed is passed through the re-discharge space, and the opposing surfaces of the pair of subsequent electrodes are flat surfaces, a flat surface and a convex cylindrical surface, or a concave cylindrical surface and a convex cylindrical surface, To do.

In the main processing unit, reaction components are reacted to some extent by plasma irradiation in the main discharge space. At this time, it can prevent that a to-be-processed film covers a 1st roll electrode and a 2nd roll electrode, and a dirt adheres to a 1st, 2nd roll electrode. As a result, generation | occurrence | production of a particle can be prevented and a yield can be improved.
Thereafter, the film to be treated is again irradiated with plasma in the re-discharge space between the pair of subsequent electrodes of the reactivation unit. The opposing surfaces of the pair of subsequent electrodes are configured by planes, or one opposing surface is configured as a plane and the other opposing surface is configured as a convex cylindrical surface, or one opposing surface is configured as a concave cylindrical surface and the other opposing surface. Is configured with a convex cylindrical surface, the path length along the transport direction of the re-discharge space can be made longer than the path length along the transport direction of the main discharge space. Therefore, sufficient energy can be imparted to the surface molecules and reaction components of the film to be treated in the reactivation part, and preferably greater energy than in the main treatment part. Thereby, even if the reaction is insufficient only by the processing in the main processing unit, a sufficient degree of reactivity can be obtained by passing through the reactivation unit, and the processing effect can be enhanced.
When the reaction component is a polymerizable monomer, a polymerization reaction can be sufficiently caused, and an odor caused by an unpolymerized polymerizable monomer can be prevented from being generated from a treated film after processing. When the said to-be-processed film is a protective film of a polarizing plate, an adhesive promotion layer can be reliably formed in this protective film, and adhesiveness with a polarizing film can be improved.
Since the reaction product is not included in the discharge product gas of the reactivation part, it is possible to prevent the dirt from adhering to the electrode in the reactivation part and to prevent generation of particles. Therefore, the yield can be improved reliably.

One of the pair of post-stage electrodes of the reactivation unit has an opposing surface formed of a flat surface or a concave cylindrical surface and is opposed to the second roll electrode, and the second roll electrode is formed of the reactivation unit. It is preferably provided as the other latter-stage electrode.
The outer peripheral surface of the second roll electrode constitutes an opposing surface composed of the convex cylindrical surface. By combining the second roll electrode of the main processing unit as the electrode element of the reactivation unit, the device structure can be simplified and the manufacturing cost can be reduced.

It is preferable that the power supplied to the reactivation unit is larger than the power supplied to the main processing unit.
Thereby, the reactivity in the reactivation part can fully be raised.

The present invention is a film surface treatment apparatus that activates a reaction component to react on the surface of the film to be treated while conveying a continuous film to be treated,
A main processing unit disposed relatively upstream in the transport direction; and a reactivation unit disposed relatively downstream in the transport direction;
The main processing part is arranged in parallel so as to form a main discharge space near atmospheric pressure between each other, and the transport direction from the main discharge space in the film to be processed, the first roll electrode and the second roll electrode And a nozzle that blows out a reaction gas containing the reaction component toward the main discharge space or the main discharge space, the film to be processed being wound around the first roll electrode, and the main discharge space The first roll electrode and the second roll electrode are rotated around their own axes and in the same direction, thereby being turned around the second roll electrode. The treated film is conveyed from the first roll electrode to the second roll electrode,
The reactivation unit, and a second feature that is not claimed that the including light energy irradiating means for irradiating light energy to be processed film.

In the main processing unit, reaction components are reacted to some extent by plasma irradiation. At this time, it can prevent that a to-be-processed film covers a 1st roll electrode and a 2nd roll electrode, and a dirt adheres to a 1st, 2nd roll electrode. As a result, generation | occurrence | production of a particle can be prevented and a yield can be improved.
Then, a to-be-processed film is irradiated with light energy from a light energy irradiation means. Thereby, even if the reaction is insufficient only by the processing in the main processing section, a sufficient degree of reactivity can be obtained through the light energy irradiation means, and the processing effect can be enhanced.
When the reaction component is a polymerizable monomer, a polymerization reaction can be sufficiently caused, and an odor caused by an unpolymerized polymerizable monomer can be prevented from being generated from a treated film after processing. When the said to-be-processed film is a protective film of a polarizing plate, an adhesive promotion layer can be reliably formed in this protective film, and adhesiveness with a polarizing film can be improved. As light energy, it is preferable to use ultraviolet light energy or infrared light energy.

The surface treatment is preferably performed near atmospheric pressure. Here, the vicinity of the atmospheric pressure refers to a range of 1.013 × 10 ^{4 to} 50.663 × 10 ⁴ Pa, and considering the ease of pressure adjustment and the simplification of the apparatus configuration, 1.333 × 10 ⁴ to 10.664 × 10 ⁴ Pa is preferable, and 9.331 × 10 ^{4 to} 10.9797 × 10 ⁴ Pa is more preferable.

INDUSTRIAL APPLICABILITY The present invention is suitable for processing difficult-to-adhere optical resin films. In adhering the hardly-adhesive optical resin film to an easily-adhesive optical resin film, the adhesiveness of the hardly-adhesive optical resin film is improved. It is suitable for improving.
Examples of the main component of the hardly adhesive optical resin film include triacetate cellulose (TAC), polypropylene (PP), polyethylene (PE), cycloolefin polymer (COP), cycloolefin copolymer (COC), and polyethylene terephthalate. (PET), polymethyl methacrylate (PMMA), polyimide (PI) and the like.

  Examples of the main component of the easily adhesive optical resin film include polyvinyl alcohol (PVA) and ethylene vinyl acetate copolymer (EVA).

In the surface treatment for improving the adhesion of the hardly adhesive optical resin film, it is preferable to use a polymerizable monomer as the reaction component.
Examples of the polymerizable monomer include monomers having an unsaturated bond and a predetermined functional group. The predetermined functional group is preferably selected from a hydroxyl group, a carboxyl group, an acetyl group, a glycidyl group, an epoxy group, an ester group having 1 to 10 carbon atoms, a sulfone group, and an aldehyde group. A hydrophilic group is preferred.

Examples of the monomer having an unsaturated bond and a hydroxyl group include ethylene glycol methacrylate, allyl alcohol, and hydroxyethyl methacrylate.
Examples of the monomer having an unsaturated bond and a carboxyl group include acrylic acid, methacrylic acid, itaconic acid, maleic acid, 2-methacryloylpropionic acid and the like.
Examples of the monomer having an unsaturated bond and an acetyl group include vinyl acetate.
Examples of the monomer having an unsaturated bond and a glycidyl group include glycidyl methacrylate.
Monomers having an unsaturated bond and an ester group include methyl acrylate, ethyl acrylate, butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid. Examples include butyl, t-butyl methacrylate, isopropyl methacrylate, and 2-ethyl methacrylate.
Examples of the monomer having an unsaturated bond and an aldehyde group include acrylic aldehyde and crotonaldehyde.

Preferably, the polymerizable monomer is a monomer having an ethylenically unsaturated double bond and a carboxyl group. Examples of such monomers include acrylic acid (CH ₂ ═CHCOOH) and methacrylic acid (CH ₂ ═C (CH ₃ ) COOH). The polymerizable monomer is preferably acrylic acid or methacrylic acid. Thereby, the adhesiveness of a hardly-adhesive resin film can be improved reliably. More preferably, the polymerizable monomer is acrylic acid.

The polymerizable monomer may be conveyed by a carrier gas. The carrier gas is preferably selected from an inert gas such as nitrogen, argon or helium. From the economical viewpoint, it is preferable to use nitrogen as the carrier gas.
Many polymerizable monomers such as acrylic acid and methacrylic acid are in a liquid phase at normal temperature and pressure. Such a polymerizable monomer may be vaporized in a carrier gas such as an inert gas. As a method of vaporizing the polymerizable monomer into the carrier gas, a method of extruding a saturated vapor on the surface of the polymerizable monomer solution with the carrier gas, a method of bubbling the carrier gas into the polymerizable monomer solution, a polymerizable monomer solution For example, a method of promoting evaporation by heating can be used. Extrusion and heating, or bubbling and heating may be used in combination.

  When heating and vaporizing, it is preferable to select a polymerizable monomer having a boiling point of 300 ° C. or less in consideration of the burden on the heater. Moreover, it is preferable to select a polymerizable monomer that does not decompose (chemically change) by heating.

According to the present invention, when the reactive component is activated and the film to be processed is plasma-treated, the reaction of the reactive component can be sufficiently ensured while preventing contamination of the electrode, and the processing effect is improved. Can be increased.

It is an explanatory side view showing a schematic structure of a film surface treatment apparatus according to the first embodiment of the present invention. It is a perspective view of the principal part of the said film surface treatment apparatus. It is explanatory side view which shows schematic structure of the film surface treatment apparatus which concerns on 2nd Embodiment of this invention. It is explanatory side view which shows schematic structure of the film surface treatment apparatus which concerns on 3rd Embodiment of this invention. It is a description side view which shows schematic structure of the film surface treatment apparatus which concerns on 4th Embodiment of this invention. It is an explanatory side view which shows the modification of the electrode structure of the reactivation part. It is a description side view which shows the other modification of the electrode structure of a reactivation part.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a first embodiment of the present invention. The film 9 to be processed has a continuous sheet shape. Here, a protective film for a polarizing plate is applied as the film 9 to be processed. The protective film 9 contains triacetate cellulose (TAC) as a main component. The components of the film 9 are not limited to TAC, but polypropylene (PP), polyethylene (PE), cycloolefin polymer (COP), cycloolefin copolymer (COC), polyethylene terephthalate (PET), polymethyl methacrylate (PMMA), polyimide (PI), or the like may be used. The thickness of the film 9 is, for example, about 100 μm.

  A polarizing film made of a PVA film and a protective film are bonded together with an adhesive to constitute a polarizing plate. As the adhesive, an aqueous adhesive such as an aqueous PVA solution is used. Prior to the bonding step, the protective film is surface-treated by the film surface treatment apparatus 1 to improve the adhesion of the protective film.

  As shown in FIGS. 1 and 2, the film surface treatment apparatus 1 includes a main treatment unit 10 and a reactivation unit 30. The protective film 9 to be processed is conveyed in a substantially right direction with the width direction orthogonal to the paper surface in FIG. The main processing unit 10 is arranged on the upstream side (left side in FIG. 1) of the film 9 to be processed, and the reactivation unit 30 is arranged on the downstream side (right side in FIG. 1) of the film 9 to be processed. ing.

  The main processing unit 10 includes a pair of electrodes 11 and 12 and gas nozzles 21, 22 and 23. The electrodes 11 and 12 have a roll shape (cylindrical shape). Roll electrodes 11 and 12 are arranged in parallel to each other with their respective axes oriented in a horizontal direction perpendicular to the paper surface of FIG. Hereinafter, a direction along the axis of the electrodes 11 and 12 is appropriately referred to as a “process width direction” (see FIG. 2). In FIG. 1, the left first roll electrode 11 is connected to a power source 18. In FIG. 1, the second roll electrode 12 on the right side is electrically grounded. The power supply 18 supplies, for example, pulsed power to the electrode 11. As a result, a plasma discharge is generated between the electrodes 11 and 12 under a pressure near atmospheric pressure. A space between the portions of the roll electrodes 11 and 12 facing each other becomes a main discharge space 19 near atmospheric pressure. Specifically, the narrowest portion between the roll electrodes 11 and 12 and the space in the vicinity thereof become the main discharge space 19. Since the main discharge space 19 is defined by the outer peripheral surfaces formed by the convex cylindrical surfaces of the roll electrodes 11 and 12, the path length in the vertical direction is short. For example, when the diameter of the roll electrodes 11 and 12 is about 310 mm, the vertical path length of the main discharge space 19 is about 40 mm.

  A film 9 to be processed is wound around the upper peripheral surface of the first roll electrode 11 about a half turn. The film to be processed 9 is passed through the main discharge space 19 along the peripheral surface of the first roll electrode 11, is hung below the main discharge space 19, and is folded up by the guide rolls 16 and 16. Further, the film 9 to be processed is passed through the main discharge space 19 along the peripheral surface of the second roll electrode 12, and is wound around the upper peripheral surface of the second roll electrode 12 about a half turn. About half a circumference including a portion defining the main discharge space 19 of both roll electrodes 11 and 12 is covered with the film 9 to be processed.

  Although not shown, a rotation mechanism is connected to each of the roll electrodes 11 and 12. The rotation mechanism includes a drive unit such as a motor and a transmission unit that transmits the driving force of the drive unit to the shafts of the roll electrodes 11 and 12. The transmission means is constituted by, for example, a belt / pulley mechanism or a gear train. As shown by the white arc-shaped arrow in FIG. 1, the roll electrodes 11 and 12 are rotated around their own axes and in the same direction (clockwise in FIG. 1) in synchronization with each other by the rotation mechanism. . Thereby, the to-be-processed film 9 is conveyed from the 1st roll electrode 11 to the 2nd roll electrode 12. FIG.

  Each roll electrode 11, 12 incorporates temperature control means (not shown). The temperature adjusting means is constituted by a temperature adjusting path formed in the roll electrodes 11 and 12, for example. The temperature of the roll electrodes 11 and 12 can be controlled by flowing a temperature-controlled medium such as water through the temperature control path. As a result, the to-be-processed film 9 on the peripheral surface of the roll electrodes 11 and 12 can be temperature-controlled.

  Discharge generation gas nozzles 21 and 22 are respectively disposed above and below the main discharge space 19 between the roll electrodes 11 and 12. A discharge generated gas supply source 24 is connected to each of the nozzles 21 and 22. The upper nozzle 21 extends long in the processing width direction, and a cross section perpendicular to the extending direction tapers downward. The outlet at the lower end (tip) of the nozzle 21 faces the main discharge space 19. The upper end of the main discharge space 19 is blocked to some extent by the nozzle 21. A rectifying unit (not shown) is provided on the upper side of the nozzle 21, and discharge generated gas is made uniform in the processing width direction and introduced into the nozzle 21. This discharge generated gas is blown out from the blowout port at the lower end of the nozzle 21 into the main discharge space 19. The discharge flow of the discharge product gas is a uniformly distributed flow in the processing width direction.

  The lower nozzle 22 has a shape obtained by inverting the upper nozzle 21 up and down. That is, the lower nozzle 22 extends long in the processing width direction, and a cross section perpendicular to the extending direction tapers upward. An outlet at the upper end (tip) of the nozzle 22 faces the main discharge space 19. The lower end portion of the main discharge space 19 is blocked to some extent by the nozzle 22. A rectifying unit (not shown) is provided at the lower end of the nozzle 22, and discharge generated gas is made uniform in the processing width direction and introduced into the nozzle 22. This discharge generated gas is blown out from the outlet of the nozzle 22 into the main discharge space 19. The discharge flow of the discharge product gas is a uniformly distributed flow in the processing width direction.

  The discharge generated gas may be blown out from the upper and lower nozzles 21 and 22 at the same time. The gas is blown out from only one of the upper and lower nozzles 21 and 22, and the other nozzle is used as a closing member for closing the upper end or the lower end of the main discharge space 19. It may be used. For example, the discharge generated gas may be blown out only from the lower nozzle 22 and the gas may not be blown out from the upper nozzle 21.

An inert gas is used as the discharge product gas. Although nitrogen (N ₂₎ can be mentioned as an inert gas for discharge product gas, not limited to this, Ar, may be used a noble gas such as He.

  A reactive gas nozzle 23 is disposed above the first roll electrode 11 so as to face the electrode 11. The reactive gas nozzle 23 is separated from the main discharge space 19 along the circumferential direction of the first roll electrode 11 by about a quarter of the turn in the electrode rotation direction and thus upstream in the film transport direction. The reactive gas nozzle 23 faces the film 9 to be processed on the electrode 11 on the upstream side in the transport direction from the main discharge space 19. The reactive gas nozzle 23 extends long in the processing width direction and has a certain width in the circumferential direction of the first roll electrode 11 (left and right in FIG. 1). Although not shown in detail, a rectification unit is incorporated in the reaction gas nozzle 23. An outlet is provided on the lower surface of the reactive gas nozzle 23. The outlets are formed so as to be distributed over a wide range (the processing width direction and the electrode circumferential direction) of the lower surface of the nozzle 23.

  A reactive gas supply source 20 is connected to the nozzle 23. The reaction gas from the supply source 20 is supplied to the nozzle 23. The reaction gas is made uniform by the rectifying unit and blown out from the blowout port on the lower surface of the nozzle 23. The blow-out flow of the reaction gas is a flow that is uniformly distributed in the processing width direction.

The reaction gas contains a polymerizable monomer as a reaction component. Here, acrylic acid AA is used as the polymerizable monomer. Acrylic acid has an acetic acid-like odor and has explosive properties, and therefore requires appropriate management. The polymerizable monomer is not limited to acrylic acid, and may be methacrylic acid, itaconic acid, maleic acid, or the like. The reaction gas further includes a carrier gas in addition to the reaction component (polymerizable monomer). An inert gas is used as the carrier gas. Here, nitrogen (N ₂ ) is used as the inert gas for the carrier gas, but the present invention is not limited to this, and a rare gas such as Ar or He may be used.

The reactive gas supply source 20 is constituted by a vaporizer. Acrylic acid AA is stored in the vaporizer as a polymerizable monomer in a liquid state. Nitrogen (N ₂ ) is introduced into the vaporizer as a carrier gas. Acrylic acid is vaporized and mixed with this carrier gas (N ₂ ) to generate a reaction gas (acrylic acid AA + N ₂ ). The carrier gas may be introduced above the liquid acrylic acid level in the vaporizer, or may be introduced into the liquid acrylic acid and bubbled. A part of the carrier gas may be introduced into the vaporizer and the remaining part may not be passed through the vaporizer, and the part of the carrier gas and the remaining part may be merged on the downstream side of the vaporizer. The acrylic acid concentration in the reaction gas can be adjusted according to the temperature of the vaporizer and the distribution ratio of the part and the remainder of the carrier gas.
The reaction gas supply line from the reaction gas supply source 20 to the nozzle 23 is temperature-controlled by a reaction gas temperature adjusting means (not shown) such as a ribbon heater.

  A shielding member 40 is provided above the first roll electrode 11. The shielding member 40 has a curved plate shape extending in the processing width direction substantially the same length as the electrode 11 and having a cross section orthogonal to the extending direction forming an arc shape along the circumferential direction of the first roll electrode 11. The shielding member 40 covers the upper peripheral surface of the first roll electrode 11 to some extent. The reaction gas nozzle 23 is connected to the central portion of the shielding member 40 in the arc direction (left and right in FIG. 1). Both ends of the shielding member 40 in the arc direction extend from the nozzle 23 in the circumferential direction of the electrode 11. The end of the shielding member 40 on the nozzle 21 side (right side in FIG. 1) is abutted against and connected to the side of the nozzle 21.

  A shielding space 41 is formed between the shielding member 40 and the peripheral surface of the first roll electrode 11. The shielding space 41 is along the upper peripheral surface of the first roll electrode 11. The outlet on the lower surface of the reactive gas nozzle 23 penetrates the shielding member 40 and communicates with the shielding space 41. An end portion of the shielding space 41 on the nozzle 21 side (right side in FIG. 1) is connected to the main discharge space 19 through a space between the nozzle 21 and the peripheral surface of the first roll electrode 11. The end of the shielding space 41 opposite to the nozzle 21 (left side in FIG. 1) is open to the outside.

  In the film surface treatment apparatus 1, a reactivation unit 30 is provided in addition to the main treatment unit 10. The reactivation unit 30 is disposed downstream of the main discharge space 19 in the transport direction of the film 9 to be processed. The reactivation unit 30 includes one or a plurality of (two in the drawing) rear electrodes 31. The rear electrode 31 has a flat plate shape extending in the processing width direction. Each subsequent-stage electrode 31 is disposed above the second roll electrode 12 and faces the peripheral surface on the upper side of the second roll electrode 12. A plurality of subsequent electrodes 31, 31 are arranged at intervals in the circumferential direction of the second roll electrode 12.

  The length of each rear electrode 31 in the processing width direction is substantially equal to the axial length of the second roll electrode 12. The dimension along the circumferential direction of the electrode 12 of each rear electrode 31 is, for example, about 20 mm to 40 mm. The arrangement pitch of the adjacent rear electrodes 31 and 31 is, for example, about 20 mm to 40 mm.

  The lower surface of each rear electrode 31 is a surface 31 a facing the second roll electrode 12. The facing surface 31a is a flat surface. A solid dielectric 32 is provided on the facing surface 31a. The solid dielectric 32 is configured by a flat plate made of ceramic such as alumina, but may be a film coated on the opposing surface 31a by thermal spraying or the like. The solid dielectric 32 is not limited to ceramic but may be other dielectrics such as resin.

  Each post-stage electrode 31 is connected to a reactivation power supply 38. The power supply 38 supplies, for example, pulsed power to each electrode 31. As a result, an electric field is applied between the grounded second roll electrode 12 and each subsequent electrode 31 to generate a plasma discharge near atmospheric pressure. A space between the solid dielectric 32 and the second roll electrode 12 of each rear electrode 31 becomes a re-discharge space 39 near atmospheric pressure.

  The second roll electrode 12 is provided as the other rear electrode that is paired with the rear electrode 31 in the reactivation unit 30. In addition, one second roll electrode 12 is paired with a plurality of electrodes 31, 31.

  The opposing surface 31a of one rear electrode 31 constituting the reactivation unit 30 is a flat surface, and the opposing surface of the other rear electrode 12 is a convex cylindrical surface. Therefore, the path length along the circumferential direction of the electrode 12 in each redischarge space 39 is larger than the path length of the main discharge space 19. The total path length of the plurality of re-discharge spaces 39 of the reactivation unit 30 is naturally larger than the path length of the main discharge space 19.

  The power supplied to the reactivation unit 30 is larger than the power supplied to the main processing unit 10. Here, the power supplied to the reactivation unit 30 refers to the total power supplied to the plurality of electrodes 31 and 31. The power supplied to the reactivation unit 30 is, for example, 1.5 to 2.0 times the power supplied to the main processing unit 10.

  A gas supply unit 33 is connected to each re-discharge space 39. The gas supply unit 33 supplies the discharge generated gas to the redischarge space 39. Although detailed illustration is omitted, the gas supply unit 33 includes a rectification unit and a nozzle. The nozzle of the supply unit 33 faces the re-discharge space 39 and extends in the processing width direction. The discharge generated gas is made uniform in the processing width direction by the rectifying unit of the supply unit 33 and then blown out from the nozzle to the re-discharge space 39. The discharge flow of the discharge product gas is uniformly distributed in the processing width direction.

Nitrogen (N ₂ ) is used as the discharge product gas of the gas supply unit 33. An inert gas other than nitrogen (for example, a rare gas such as Ar or He) may be used as the discharge generation gas of the gas supply unit 33. The discharge generated gas of the gas supply unit 33 does not contain a polymerizable monomer.
The discharge generated gas supply source of the gas supply unit 33 may be shared with the discharge generated gas supply source of the nozzles 21 and 22. A supply path extending from one discharge generation gas supply source may be branched and connected to the nozzles 21 and 22 and the gas supply unit 33.

A method for surface-treating the film 9 to be processed by the film surface treatment apparatus 1 having the above configuration will be described.
The film to be treated 9 is wound around the roll electrodes 11 and 12.
The roll electrodes 11 and 12 are rotated clockwise in FIG. 1, and the film 9 to be processed is conveyed substantially rightward in FIG.
A reactive gas (acrylic acid + N ₂ ) is introduced from the supply source 20 into the nozzle 23 and blown out from the nozzle 23 into the shielding space 41. This reaction gas comes into contact with the film 9 to be processed on the upper peripheral surface of the first roll electrode 11, and acrylic acid (reaction component) in the reaction gas condenses and adheres to the film 9 to be processed.
By the shielding member 40, the reactive gas can be confined in the shielding space 41, and acrylic acid can be prevented or suppressed from leaking into the external atmosphere. As a result, the opportunity for acrylic acid to contact the film 9 to be processed can be increased, and acrylic acid can be reliably attached to the film 9 to be processed. In addition, atmospheric gas containing oxygen such as external air can be prevented from entering the shielded space 41.

The portion of the film 9 to which the acrylic acid adheres is introduced into the main discharge space 19 by the conveyance of the film 9 to be processed.
A discharge generated gas (N ₂ ) is supplied to the main discharge space 19 from the nozzle 21 or 22. In parallel, power is supplied to the electrode 11 to generate an atmospheric pressure plasma discharge in the main discharge space 19. As a result, in the main discharge space 19, the nitrogen of the discharge product gas is turned into plasma and nitrogen plasma is generated. The film 9 to be treated is irradiated with the nitrogen plasma or plasma light, and bonds such as C—C, C—O, and C—H of the surface molecules of the film 9 to be treated are cut. Furthermore, the acrylic acid on the surface of the film to be treated 9 is activated by the plasma, the double bond is cleaved, polymerized, etc., and the polymer of acrylic acid is bonded to the bond cutting portion of the film to be treated 9 (graft polymerization). Alternatively, it is considered that a COOH group decomposed from acrylic acid is bonded. Thereby, an adhesion promoting layer is formed on the surface of the film 9 to be processed.
Since the shielding member 40 can prevent the outside atmosphere from entering, it is possible to prevent or suppress the reaction in the main discharge space 19 from being hindered by oxygen in the outside atmosphere.

  The film 9 to be processed passes through the main discharge space 19 in contact with the first roll electrode 11, is turned back by the guide roll 16, and passes through the main discharge space 19 again in contact with the second roll electrode 12. Therefore, the film to be processed 9 is processed twice in the main discharge space 19.

Subsequently, the film 9 to be processed moves in the circumferential direction of the second roll electrode 12 and is introduced into the redischarge space 39 of the reactivation unit 30.
A discharge generated gas (N ₂ ) is supplied from the gas supply unit 33 to the re-discharge space 39. In parallel, power is supplied to the electrode 31 to generate an atmospheric pressure plasma discharge in the redischarge space 39. As a result, nitrogen in the discharge generated gas is turned into plasma in the redischarge space 39 to generate nitrogen plasma. The By irradiating the film to be processed 9 with this nitrogen plasma or plasma light, the bond molecules such as C—C, C—O, and C—H of the surface molecules of the film to be processed 9 again occur. Furthermore, unpolymerized acrylic acid on the surface of the film 9 to be processed and acrylic acid having a low degree of polymerization are activated, and polymerization proceeds. It is considered that this polymer of acrylic acid is bonded (graft polymerization) to the bond cutting portion of the film 9 to be processed, or a COOH group decomposed from acrylic acid is bonded.

  Since the path length of the re-discharge space 39 is larger than the path length of the main discharge space 19, the film to be processed 9 and the acrylic acid on the surface thereof can be exposed to the plasma for a longer time than the main discharge space 19. Sufficient energy can be imparted to the surface molecules and acrylic acid. Thereby, it can fully polymerize without remaining acrylic acid, and can form an adhesion promotion layer on the surface of the to-be-processed film 9 reliably. Accordingly, it is possible to prevent an acetic acid-like odor peculiar to acrylic acid from being processed. In the subsequent bonding step, the film to be processed 9 and the PVA film can be reliably bonded with the water-based adhesive, and an unbonded portion can be prevented from being formed. Therefore, a polarizing plate having good adhesive strength can be manufactured.

  Since the to-be-processed film 9 has covered especially the part which defines the discharge space 19 of each roll electrode 11 and 12, it can prevent that dirt adheres to these electrodes 11 and 12. FIG. Further, since acrylic acid (reaction component) is not supplied to the reactivation unit 30, contamination of the electrode 31 can be prevented or suppressed. Accordingly, generation of particles can be prevented or suppressed, and the yield can be improved.

By using the second roll electrode 12 as an electrode element of the reactivation unit 30, the number of parts can be reduced and the device configuration can be simplified. In addition, since one roll electrode 12 is paired with a plurality of subsequent electrodes 31, 31, the number of parts can be further reduced, and the apparatus configuration can be simplified.
Since the number of roll electrodes in the entire film surface treatment apparatus 1 is two and the electrode 31 can be composed of a metal flat plate or the like, an increase in manufacturing cost of the film surface treatment apparatus 1 can be suppressed.

Next, another embodiment of the present invention will be described. In the following embodiments, the same reference numerals are attached to the drawings for the same contents as those of the above-described embodiments, and the description thereof is omitted.
FIG. 3 shows a film surface treatment apparatus 1A according to the second embodiment of the present invention. The film surface treatment apparatus 1A of the second embodiment is different from the film surface treatment apparatus 1 (FIG. 1) of the first embodiment in that the reaction gas nozzle 23 and the shielding member 40 of the main processing unit 10 are omitted. A reactive gas supply source 20 is connected to the upper nozzle 21. The reactive gas supply source 20 may be connected to the lower nozzle 22 instead of the upper nozzle 21, or may be connected to both the upper nozzle 21 and the lower nozzle 22.

In the second embodiment, the reaction gas (acrylic acid AA + N ₂ ) is sent from the supply source 20 to the nozzle 21 and blown out from the nozzle 21 into the main discharge space 19. Therefore, the acrylic acid is sprayed onto the film 9 to be treated and the polymerization reaction is performed almost simultaneously, and an adhesion promoting layer is formed. The carrier gas (N ₂ ) in the reaction gas also serves as a discharge product gas and is converted into plasma in the main discharge space 19, thereby contributing to the formation of the adhesion promoting layer.

  FIG. 4 shows a film surface treatment apparatus 1B according to the third embodiment of the present invention. The film surface treatment apparatus 1B includes three roll electrodes 11, 12, and 34 as a whole. Three roll electrodes 11, 12, and 34 are arranged in a line in this order. A film to be processed 9 is wound around these roll electrodes 11, 12 and 34. Although not shown, the electrode rotation mechanism is connected to the third roll electrode 34 in addition to the first and second roll electrodes 11 and 12. The three roll electrodes 11, 12, and 34 rotate in synchronization with each other, and the film 9 to be processed is conveyed rightward in FIG. 4 in the order of the first roll electrode 11, the second roll electrode 12, and the third roll electrode 34.

  In the third embodiment, the power source 18 is connected not to the first roll electrode 11 but to the central second roll electrode 12. The first roll electrode 11 and the third roll electrode 34 are electrically grounded. Therefore, the ground electrode 11, the hot electrode 12, and the ground electrode 34 are arranged in this order along the transport direction of the film 9 to be processed. As in the first embodiment (FIG. 1), a main discharge space 19 is formed between the first and second roll electrodes 11 and 12. Furthermore, a discharge space is also formed between the second roll electrode 12 and the third roll electrode 34. A discharge generated gas such as nitrogen may be supplied also to the discharge space between the electrodes 12 and 34.

  The third roll electrode 34 constitutes the other rear electrode that forms a pair with the rear electrode 31 in the reactivation unit 30. One or a plurality of (two in the figure) rear electrodes 31 are disposed above the roll electrode 34 instead of the second roll electrode 12. A facing surface 31 a forming a flat surface of each electrode 31 faces a circumferential surface forming a convex cylindrical surface of the roll electrode 34. A redischarge space 39 is formed between each electrode 31 and the roll electrode 34.

In the third embodiment, after the film to be processed 9 is plasma-treated in the discharge space 19 between the first and second roll electrodes 11 and 12, the discharge between the second and third roll electrodes 12 and 34 is performed. Plasma treatment can be performed again in the space. Then, the to-be-processed film 9 can be introduce | transduced into the re-discharge space 39 of the reactivation part 30, and can further be plasma-processed. Thereby, acrylic acid can be more fully polymerized and an adhesion promoting layer can be reliably formed.
Since the to-be-processed film 9 has covered all (three) roll electrodes 11, 12, and 34, it can prevent that these electrodes 11, 12, and 34 become dirty.

FIG. 5 shows a film surface treatment apparatus 1C according to a fourth embodiment corresponding to the second unclaimed feature of the present invention. In the film surface treatment apparatus 1 </ b> C, a light energy irradiation unit 50 is provided as a reactivation unit subsequent to the main processing unit 10 in place of the plasma processing unit 30. The light energy irradiation means 50 is constituted by an infrared lamp or an ultraviolet lamp. The light energy irradiation means 50 is arranged to face the film 9 to be processed on the downstream side in the transport direction from the second roll electrode 12. The light emitting part of the light energy irradiation means 50 extends in the processing width direction (direction orthogonal to the paper surface of FIG. 5) for substantially the same length as the film 9.
The light energy irradiation means 50 may be disposed so as to face the peripheral surface of the second roll electrode 12.

  Infrared light or ultraviolet light 51 (light energy) from the light energy irradiation means 50 is irradiated almost uniformly in the processing width direction on the film 9 to be processed after passing through the main processing portion 10. Thereby, energy can be provided again to the surface molecules of the film to be processed 9 and acrylic acid, and the polymerization reaction of acrylic acid can be caused again. As a result, similar to the first embodiment, acrylic acid can be sufficiently polymerized to reliably form the adhesion promoting layer on the surface of the film 9 to be processed, and the adhesion can be improved.

The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the first to third embodiments, the number of the rear electrodes 31 of the reactivation unit 30 may be one or three or more.
The electrode structure of the reactivation unit 30 may be such that the path length of the redischarge space 39 is longer than the path length of the discharge space 19 of the electrodes 11 and 12 with the convex cylindrical surfaces of the main processing unit 10 facing each other. It is not limited to the combination of the electrode 31 and the electrodes 12 and 34 in which the plane and the convex cylindrical surface are opposed to each other. For example, as shown to Fig.6 (a), the reactivation part 30 may be comprised with the parallel plate electrode with which both electrodes 35 and 35 made plane 35a, 35a and each face each other. The film to be processed 9 is passed between the electrodes 35 and 35. Alternatively, as shown in FIG. 6B, the opposing surface of one electrode 36 of the reactivation unit 30 may be a concave cylindrical surface 36a, and the opposing surface of the other electrode 37 may be a convex cylindrical surface 37a. . The electrode 37 is preferably composed of a roll electrode. The film to be processed 9 is wound around the electrode 37. In the first to third embodiments, a concave cylindrical surface electrode 36 may be used instead of the flat plate electrode 31.

Only one of the nozzles 21 and 22 of the main processing unit 10 may be provided and the other may be omitted.
In the first, third, and fourth embodiments, the shielding member 40 may be omitted.
A plurality of embodiments may be combined with each other. For example, the structure of the main processing unit 10 of the second embodiment may be applied to the third to fourth embodiments.
The reactivation unit may include a plasma processing unit 30 including a pair of electrodes and a light energy irradiation unit 50.

The present invention is not limited to the surface treatment of the protective film for a polarizing plate, but can be applied to the surface treatment of various resin films. Furthermore, the present invention is not limited to plasma polymerization treatment of a polymerizable monomer, but can be applied to various plasma surface treatments such as plasma CVD, plasma cleaning, and plasma surface modification. In these various plasma surface treatments, a sufficient degree of treatment can be obtained, dirt can be prevented from adhering to the roll electrodes 11 and 12 of the main treatment unit 10, and the electrode 31 of the reactivation unit 30 and the like can be further prevented. Can be suppressed or prevented from being contaminated by the reaction component, and as a result, generation of particles can be prevented and yield can be improved.
The reaction component of the reaction gas is appropriately selected according to the processing content. For example, as a reaction component used in plasma CVD, TMOS (tetramethoxysilane), TEOS (tetraethoxysilane), and the like can be given.

Although an Example is described, this invention is not limited to a following example.
In Example 1, using the film surface treatment apparatus 1 shown in FIG. 1, following the plasma treatment by the main treatment unit 10, re-plasma treatment by the reactivation unit 30 was performed.
A TAC film was used as the film 9 to be processed. The width of the TAC film 9 was 330 mm.
The conveyance speed of the TAC film 9 was 15 m / min.
The temperature of the electrodes 11 and 12, and thus the temperature of the TAC film 9, was set to 25 ° C.
Acrylic acid was used as the polymerizable monomer for the reaction gas, and nitrogen was used as the carrier gas.
The temperature of the liquid acrylic acid in the vaporizer 20 was set to 70 ° C.
The flow rate of the carrier gas (N ₂ ), and hence the flow rate of the reaction gas (acrylic acid + N ₂ ), was 40 slm.
The discharge generated gas (N ₂ ) was blown out only from the lower nozzle 22 among the upper and lower nozzles 21, 22 and supplied to the main discharge space 19. The gas blowing width of the nozzle 22 was 325 mm. The N ₂ supply flow rate from the nozzle 22 was 20 slm.
The diameter of each roll electrode 11 and 12 was 320 mm. The axial length of each roll electrode 11 and 12 was 340 mm.
The narrowest gap (the thickness of the main discharge space 19) between the roll electrodes 11 and 12 was 1 mm.
The power supplied to the electrode 11 was 1100W.
The applied voltage between the electrodes 11 and 12 was Vpp = 18.0 kV.

The length of each post-stage electrode 31 in the processing width direction (dimension in the direction perpendicular to the plane of FIG. 1) was 340 mm. The dimension of the film conveyance direction (left-right direction of FIG. 1) of each back | latter stage electrode 31 was 20 mm.
The distance between the lower surface 31a of each electrode 31 and the outer peripheral surface of the second roll electrode 12 was 1 mm.
The thickness of the solid dielectric 32 was 1 mm.
The power supplied to each electrode 31 was 600W. Therefore, the total supply power of the two electrodes 31 was 1200 W.
The applied voltage between the electrodes 31 and 12 was Vpp = 18.0 kV.
The supply flow rate of the discharge generated gas (N ₂ ) to each redischarge space 39 was 20.0 L / min.

  The TAC film after the surface treatment did not give an acetic acid odor peculiar to acrylic acid. When pure water was dropped on the surface of the TAC film after the above treatment and the pH of the pure water was measured, pH = 7. For pH measurement, Testo Co., Ltd., model number TESTO230 was used. The above pH measurement results indicate that almost no acrylic acid remains as a monomer on the surface of the TAC film, and the polymerization reaction has been sufficiently performed.

  The to-be-treated TAC film 9 after the surface treatment was bonded to one side of the PVA film. As the adhesive, an aqueous solution obtained by mixing (A) a 5 wt% PVA aqueous solution with a polymerization degree of 500 and (B) a 2 wt% aqueous sodium carboxymethylcellulose solution was used. The mixing ratio of (A) and (B) was (A) :( B) = 20: 1. The adhesive was dried at 80 ° C. for 5 minutes. A saponified TAC film was bonded to the opposite surface of the PVA film with the same adhesive as described above. Thereby, a polarizing plate sample having a three-layer structure was produced. The width of the polarizing plate sample was 25 mm.

After the adhesive was cured, the adhesive strength between the treated TAC film 9 and the PVA film was measured by the floating roller method (JIS K6854).
As a result of the measurement, the adhesive strength was 9.8 N / 25 mm.

[Comparative Example 1]
As a comparative example, plasma processing of the TAC film 9 was performed using an apparatus having the same structure as the film surface processing apparatus 1 of FIG. 1 except that the reactivation unit 30 (electrode 31) was omitted. The processing conditions were the same as the processing conditions in the main processing unit 10 of Example 1.
The TAC film after the surface treatment had an acetic acid odor peculiar to acrylic acid. When the pH of the surface of the TAC film after the above treatment was measured by the same measuring means as in Example 1, it was pH = 4. The above pH measurement results indicate that the acrylic acid monomer still remains on the surface of the TAC film and the polymerization is insufficient.

Further, in the same manner as in Example 1, a polarizing plate sample was produced and the adhesive strength was measured.
As a result of the measurement, the adhesive strength was 8.5 N / 25 mm.
According to the device of the present invention, by providing the reactivation part 30 and performing the replasma treatment, the adhesive strength could be increased by 1 N / 25 mm or more compared to the case where the replasma treatment was not performed (Comparative Example 1).

In Example 2, the film surface treatment apparatus 1 </ b> C shown in FIG. 5 was used, and light irradiation by the light energy irradiation means 50 was performed following the plasma processing by the main processing unit 10.
The plasma processing conditions in the main processing unit 10 are the same as those in the first embodiment.
As the light energy irradiation means 50, an infrared lamp (manufactured by Hybek, model number HYP45) was used. The distance between the light exit surface of the light energy irradiation means 50 and the TAC film 9 was 10 mm. The wavelength of the irradiation light from the light energy irradiation means 50 was 0.8 μm, and the illuminance was 15 W / cm ² .
The TAC film after the surface treatment did not give an acetic acid odor peculiar to acrylic acid. When the pH of the surface of the TAC film after the above treatment was measured by the same measuring means as in Example 1, it was pH = 7. This result indicates that the acrylic acid remaining as a monomer is almost absent and the polymerization reaction is sufficiently performed.
Further, in the same manner as in Example 1, a sample was prepared and the adhesive strength was measured.
As a result of the measurement, the adhesive strength was 9.5 N / 25 mm.

  The present invention is applicable, for example, to the manufacture of flat panel display (FPD) polarizing plates and various semiconductor devices.

1, 1A, 1B, 1C Film surface treatment apparatus 9 Film to be treated 10 Main treatment section 11 First roll electrode 12 Second roll electrode 16 Guide roll 18 Power supply 19 Main discharge space 20 Reactive gas supply source (vaporizer)
21 upper discharge generation gas nozzle 22 lower discharge generation gas nozzle 23 reaction gas nozzle 24 discharge generation gas source 30 reactivation part 31 rear stage electrode 31a facing surface 32 solid dielectric 33 gas supply part 34 roll electrode 35 for reactivation parallel plate electrode 36 Recessed cylindrical surface electrode 37 Roll (convex cylindrical surface) electrode 38 Reactivation power source 39 Redischarge space 40 Shielding member 41 Shielding space 50 Light energy irradiation means 51 Irradiation light

Claims (4)

A film surface treatment apparatus that activates reaction components to react on the surface of the film to be treated while conveying a continuous film to be treated,
A main processing unit disposed relatively upstream in the transport direction; and a reactivation unit disposed relatively downstream in the transport direction;
The main processing part is arranged in parallel so as to form a main discharge space near atmospheric pressure between each other, and the transport direction from the main discharge space in the film to be processed, the first roll electrode and the second roll electrode And a nozzle that blows out a reaction gas containing the reaction component toward the main discharge space or the main discharge space, the film to be processed being wound around the first roll electrode, and the main discharge space The first roll electrode and the second roll electrode are rotated around their own axes and in the same direction, thereby being turned around the second roll electrode. The treated film is conveyed from the first roll electrode to the second roll electrode,
The reactivation unit includes a pair of rear electrodes in which a redischarge space near atmospheric pressure is formed between each other, and a gas supply unit that supplies a discharge generation gas that does not contain the reaction component between the rear electrodes. The film to be processed is passed through the re-discharge space, and the opposing surfaces of the pair of subsequent electrodes are flat surfaces, a flat surface and a convex cylindrical surface, or a concave cylindrical surface and a convex cylindrical surface. Surface treatment equipment. One of the pair of post-stage electrodes of the reactivation unit has an opposing surface formed of a flat surface or a concave cylindrical surface and is opposed to the second roll electrode, and the second roll electrode is formed of the reactivation unit. The film surface treatment apparatus according to claim 1, wherein the film surface treatment apparatus is provided as the other latter-stage electrode. The film surface treatment apparatus according to claim 1, wherein the power supplied to the reactivation unit is larger than the power supplied to the main processing unit. The reaction components, the film surface treatment apparatus according to any one of claim 1 to 3, characterized in that a polymerizable monomer.