TW201302877A - Method and apparatus for treating film surface - Google Patents

Abstract

To improve adhesive strength of a polymethylmethacrylate (PMMA) film. In this film surface treatment method, a first reaction gas containing an acrylic acid is blown out from a first reaction gas nozzle (23), and is brought into contact with the PMMA film (first contact step). Then, in a gap (14) between a first roll electrode (11) and a second roll electrode (12), the PMMA film is irradiated with argon plasma (first irradiation step). Then, a second reaction gas containing the acrylic acid is blown out from a second reaction gas nozzle (43), and is brought into contact with the PMMA film (second contact step). Then, in a gap (15) between the second roll electrode (12) and a third roll electrode (13), the PMMA film is irradiated with the argon plasma (second irradiation step).

Description

Membrane surface treatment method and device

The present invention relates to a method and apparatus for treating the surface of an optical resin film, and more particularly to a resin film suitable for improving polymethylmethacrylate (hereinafter referred to as "PMMA") as a main component (hereinafter A surface treatment method and apparatus called "PMMA film".

For example, in Patent Documents 1 and 2, in order to improve the adhesion of the protective film of the polarizing plate, a gas containing a polymerizable monomer is brought into contact with the protective film and irradiated with plasma. As the polymerizable monomer, for example, acrylic acid is used. An example of the protective film is a PMMA film. An example of the gas for plasma generation is argon. The protective film which has been subjected to the treatment is bonded to the polarizing film via an adhesive to form a polarizing plate. As the adhesive, a water-based adhesive such as polyvinyl alcohol (hereinafter referred to as "PVA", polyvinyl alcohol) or a polyether-based adhesive can be used. As the polarizing film, a resin film containing PVA as a main component (hereinafter referred to as "PVA film") can be used.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2010-150372 (0013, 0017) [Patent Document 2] Japanese Patent Laid-Open Publication No. 2010-150373 (0011, 0018)

However, the PMMA film is extremely difficult to bond to the film. Although the corona discharge treatment or the adhesion of the adhesive was carried out to improve the adhesion, the adhesion was not sufficient in the treatment.

The method of the present invention is characterized in that it is a film surface treatment method for treating the surface of a PMMA film; and includes the following steps: a first contacting step of first reacting a gas obtained by vaporizing acrylic acid in a carrier gas Contacting the PMMA film; the first irradiation step is performed after the first contacting step or simultaneously with the first contacting step, irradiating the argon plasma generated near the atmospheric pressure to the PMMA film; and the second contacting step After the first irradiation step, the second reaction gas obtained by vaporizing acrylic acid in the carrier gas is brought into contact with the PMMA film; and the second irradiation step is performed after the second contact step or the second contact At the same time, an argon plasma generated under the vicinity of atmospheric pressure is irradiated to the above PMMA film.

By the first contacting step, the first condensed layer of acrylic acid can be formed on the surface of the PMMA film. Next, the first condensation layer is plasma-polymerized by the first irradiation step to form a first plasma polymerization film of polyacrylic acid. Next, a second condensed layer of acrylic acid can be formed on the first plasma polymer film by the second contacting step. Next, the second condensation layer is plasma-polymerized by the second irradiation step to form a second plasma polymerization film of polyacrylic acid on the first plasma polymerization film. The first and second plasma polymerization membranes are formed It is an adhesion promoting layer of the PMMA film. Thereby, the adhesion strength of the PMMA film which is difficult to bond can be improved, and the adhesion durability can be sufficiently improved. Here, the term "adhesive durability" refers to the extent to which the subsequent object is exposed to a high-humidity, high-temperature moist heat environment, and then the strength is not lowered.

The apparatus of the present invention is characterized in that it is a film surface treatment apparatus for treating the surface of a PMMA film; and includes: first, second, and third roller electrodes which are arranged in parallel with each other and adjacent to each other a discharge is generated in the vicinity of the atmospheric pressure in the gap; the first reaction gas nozzle faces the peripheral surface of the first roller electrode to eject a first reaction gas containing acrylic acid; and the first discharge gas nozzle ejects argon to the first roller electrode a second reaction gas nozzle that discharges a second reaction gas containing acrylic acid toward a circumferential surface of the second roller electrode; and a second discharge gas nozzle that ejects argon into the gap between the second roller electrode and the second roller electrode a gap between the second roller electrode and the third roller electrode; and the PMMA film is wound around the first, second, and third roller electrodes, and the first, second, and third roller electrodes are The PMMA film is transferred in the order of the first roller electrode, the second roller electrode, and the third roller electrode in the order of rotation.

While the PMMA film is being transferred in the order of the first roller electrode, the second roller electrode, and the third roller electrode, the first reaction gas is sprayed from the first reaction gas nozzle onto the PMMA film on the circumferential surface of the first roller electrode. Thereby, the first condensed layer of acrylic acid can be formed on the surface of the PMMA film. Then, at the first and second roller electrodes The PMMA film was irradiated with argon plasma in the gap therebetween. Thereby, the first condensation layer can be plasma-polymerized to form a first plasma polymerization film of polyacrylic acid. Then, the second reaction gas is sprayed from the second reaction gas nozzle onto the PMMA film on the circumferential surface of the second roller electrode. Thereby, the second condensed layer of acrylic acid can be formed on the first plasma polymer film. Thereafter, the PMMA film was irradiated with argon plasma in the gap between the second and third roll electrodes. Thereby, the second condensation layer can be plasma-polymerized to form a second plasma polymerization film of polyacrylic acid on the first plasma polymerization film. As a result, the adhesion strength of the PMMA film which is difficult to bond can be improved, and the adhesion durability can be sufficiently improved. The first, second, and third roller electrodes also serve as a support mechanism and a transport mechanism for the PMMA film.

Preferably, the carrier gas of the first and second reaction gases is argon. Thereby, even if the carrier gas flows into the space where the first and second irradiation steps are performed (for example, the gap between the roller electrodes), the discharge state can be prevented from changing. Further, in order to reduce the running cost, the carrier gas may be nitrogen.

The above surface treatment is preferably carried out in the vicinity of atmospheric pressure. Here, the vicinity of the atmospheric pressure means a range of 1.013 × 10 ⁴ to 50.663 × 10 ⁴ Pa, and in consideration of ease of pressure adjustment or simplification of the device configuration, it is preferably 1.333 × 10 ⁴ to 10.664 × 10 ⁴ Pa. More preferably, it is 9.331 × 10 ⁴ ~ 10.397 × 10 ⁴ Pa.

According to the present invention, the adhesion strength of the PMMA film which is difficult to bond can be improved, and the adhesion durability can be sufficiently improved.

Hereinafter, embodiments of the present invention will be described based on the drawings.

Fig. 1 shows a first embodiment of the present invention. The object to be treated is a PMMA film 9 serving as a protective film for a polarizing plate. The PMMA film 9 contains PMMA as a main component and is extremely difficult to bond. Here, the term "containing PMMA as a main component" means that the ratio of PMMA in the film 9 is 60 wt% to 100 wt%. In other words, it means that the ratio of methyl methacrylate (MMA) in the film raw material is 60 wt% to 100 wt%. Examples of the component other than PMMA of the film 9 include an ultraviolet absorber, a stabilizer, a lubricant, a processing aid, a plasticizer, an impact-resistant auxiliary, a foaming agent, a filler, a colorant, and a matting agent.

As shown in FIGS. 1 and 2, the film surface treatment apparatus 1 includes an electrode structure 10 and gas supply mechanisms 20 to 50. The electrode structure 10 includes a first roller electrode 11 , a second roller electrode 12 , and a third roller electrode 13 . The roller electrodes 11 to 13 are cylindrical bodies having the same diameter and the same axial length. At least the outer peripheral portion of the roller electrodes 11 to 13 includes a metal, and a peripheral surface of the outer periphery of the metal is covered with a solid dielectric layer. The axis of each of the roller electrodes 11, 12, and 13 is oriented in a horizontal direction orthogonal to the plane of the paper of Fig. 1 (hereinafter referred to as "processing width direction"). The three roller electrodes 11, 12, 13 are arranged in this order and in parallel. In FIG. 1, the first gap 14 between the first roller electrode 11 on the left side and the second roller electrode 12 in the center is the second gap between the second roller electrode 12 at the center and the third roller electrode 13 at the right side. The thicknesses and the like of 15 are equal to each other. The thickness of the narrowest portion of the gaps 14, 15 is preferably about 0.5 mm to 1.0 mm.

Although not shown, the power source is connected to the center roller electrode 12, and the left and right roller electrodes 11, 13 are electrically grounded. Instead, you can also connect the power supply to the left. The right roller electrodes 11, 13 and the central roller electrode 12 are electrically grounded. The power supply outputs, for example, a pulse wave of high frequency power. By this power supply, a plasma discharge is generated between the roller electrode 11 on the left side and the roller electrode 12 on the center at a pressure near atmospheric pressure, and the gap 14 becomes the first discharge space in the vicinity of the atmospheric pressure. Further, by the power supply, a plasma discharge is generated between the center roller electrode 12 and the right roller electrode 13 at a pressure near atmospheric pressure, and the gap 15 becomes a second discharge space in the vicinity of the atmospheric pressure. The applied voltage between the gaps 14 and 15 is preferably about Vpp = 6.0 kV to 7.0 kV. The frequency of the above high frequency power is preferably about 50 kHz to 70 kHz. The rise time and fall time of the above pulse are preferably 10 μsec or less. The duration of the above pulses is preferably from 1 to 1000 μsec. The high frequency is not limited to a pulse wave, and may be a continuous wave.

A plurality of (two in the drawing) front guide rollers 16, 16 are disposed below the roller electrodes 11, 12. A plurality of (two in the figure) rear guide rolls 17, 17 are disposed below the roller electrodes 12, 13.

The continuous sheet-shaped PMMA film 9 has a width direction which faces the processing width direction (the direction perpendicular to the paper surface of FIG. 1), and is wound around the circumferential surface of the upper side of the three roller electrodes 11, 12, 13 in about half a week. Approximately half of the circumferential surface including the upper surface of each of the roller electrodes 11, 12, and 13 and the portion where the gaps 14 and 15 are formed is covered by the PMMA film 9.

The PMMA film 9 between the roller electrodes 11 and 12 is suspended downward from the gap 14 and wound around the guide rolls 16 and 16. The PMMA film 9 between the gap 14 and the guide rolls 16, 16 forms a folded-back portion 9a.

The PMMA film 9 between the roller electrodes 12 and 13 hangs downward from the gap 15 And wound around the guide rolls 17, 17. The PMMA film 9 between the gap 15 and the guide rolls 17, 17 forms a folded-back portion 9b.

Although not shown in the drawings, each of the roller electrodes 11, 12, and 13 is connected to a rotating mechanism. The rotation mechanism includes a drive unit such as a motor or an internal combustion engine, and a transmission mechanism that transmits the driving force of the drive unit to the shafts of the roller electrodes 11, 12, and 13. The transmission mechanism includes, for example, a pulley mechanism or a gear train. As shown by the hollow arc-shaped arrow in Fig. 1, the roller electrodes 11, 12, 13 are respectively rotated in the same direction around the respective axes by the rotation mechanism (clockwise in Fig. 1). ) Rotate. Thereby, the PMMA film 9 is conveyed in the substantially right direction in the order of the first roller electrode 11, the second roller electrode 12, and the third roller electrode 13.

The electrode structure 10 has a function as a support mechanism for supporting the PMMA film 9 and a transport mechanism for transporting the PMMA film 9.

A temperature adjustment mechanism (not shown) is provided in each of the roller electrodes 11, 12, and 13. The temperature adjustment mechanism includes, for example, a temperature regulation path formed in the roller electrodes 11, 12, and 13. The roller electrodes 11, 12, 13 can be tempered by flowing a medium such as tempered water through a temperature regulating path. Even the PMMA film 9 on the circumferential surface of the roller electrodes 11, 12, 13 can be tempered. The set temperature of the roller electrodes 11, 12, 13 is preferably lower than the condensation temperature of the polymerizable monomer (acrylic acid). The set temperature of the PMMA film 9 is preferably about 25 ° C to 45 ° C.

The first reaction gas supply mechanism 20 includes a supply source 21 of the first reaction gas and a first reaction gas nozzle 23 . The first reaction gas contains a polymerizable monomer and a carrier gas. Acrylic acid (AA) is used as the polymerizable single system. Nitrogen (N ₂ ) is used as the carrier gas system. The first reaction gas contains a mixed gas of acrylic acid and nitrogen.

Although the detailed illustration is omitted, the first reaction gas supply source 21 includes a vaporizer. In the gasifier, the liquid acrylic acid is vaporized in the carrier gas. Gasification can be either foaming or extrusion. The first reaction gas is produced by mixing the vaporized acrylic acid with a carrier gas. Here, the foaming method refers to a method in which a carrier gas is injected into a liquid acrylic liquid in a vaporizer to vaporize acrylic acid in a bubble of a carrier gas. The extrusion method refers to a method in which a carrier gas is introduced into a space portion on the upper side of a liquid surface of a liquid acrylic acid in a vaporizer, and a saturated acrylic vapor in the space portion is mixed with a carrier gas and extruded.

The first reaction gas supply source 21 is connected to the first reaction gas nozzle 23 via the gas path 22 . The first reaction gas nozzle 23 is disposed above the first roller electrode 11 . The first reaction gas nozzle 23 extends long in the processing width direction and has a certain width in the circumferential direction of the first roller electrode 11 (left and right in FIG. 1). A discharge port is provided on a lower surface of the first reaction gas nozzle 23. The discharge port is formed to be distributed over a wide range (process width direction and roll circumferential direction) of the lower surface of the first reaction gas nozzle 23. The discharge surface (lower surface) of the first reaction gas nozzle 23 faces the PMMA film 9 on the first roller electrode 11. The first reaction gas from the first reaction gas supply source 21 is supplied to the first reaction gas nozzle 23, and is uniformed by a rectifying unit (not shown) in the first reaction gas nozzle 23, and thereafter, from the first The discharge port of the reaction gas nozzle 23 is ejected. The discharge gas stream of the first reaction gas is a gas stream uniformly distributed in the treatment width direction.

A temperature adjustment mechanism (not shown) is provided in the gas path 22 and the first reaction gas nozzle 23. The temperature regulating mechanism of the gas path 22 includes a heating belt or the like. First reaction gas The temperature regulating mechanism of the body nozzle 23 includes a temperature regulating path through which the temperature-regulating water passes. The set temperatures of the gas path 22 and the first reaction gas nozzle 23 are higher than the condensation temperature of acrylic acid. Thereby, the acrylic acid can be prevented from being condensed before being ejected. The set temperature of the gas path 22 and the first reaction gas nozzle 23 is preferably about 60 to 80 °C.

A shielding member 24 is provided on both sides of the bottom of the first reaction gas nozzle 23. The shielding member 24 is formed in an arcuate cross section along the circumferential direction of the first roller electrode 11, and has a curved plate shape extending in substantially the same length as the roller electrode 11 in the processing width direction. The shielding member 24 extends in the circumferential direction of the first roller electrode 11 from the first reaction gas nozzle 23 . In Fig. 1, the left end portion of the shielding member 24 on the left side is open. In FIG. 1, the right end portion of the shielding member 24 on the right side abuts or approaches the nozzle 34 described below.

A first spray space 25 is formed between the first reaction gas nozzle 23 and the first roller electrode 11. The first spray space 25 is a space having a circular arc shape along the circumferential surface of the upper side of the first roller electrode 11. By the shielding member 24, the first injection space 25 is extended toward both sides in the circumferential direction of the first roller electrode 11 from the first reaction gas nozzle 23. In Fig. 1, the left end portion of the first spray space 25 is connected to the outer space of the left side (the side opposite to the roll electrode 12 side) of the roller electrode 11. In FIG. 1, the end portion on the right side of the first spray space 25 is connected to the gap 14 via a gap between the nozzle 34 and the roller electrode 11 described below.

The first discharge gas supply mechanism 30 includes a first discharge gas supply source 31 and first discharge gas nozzles 33 and 34. Argon (Ar) is stored in the gas supply source 31 as the first discharge generating gas.

The gas path 32 from the gas supply source 31 is connected to the first discharge gas nozzles 33 and 34. The first discharge gas nozzles 33 and 34 are vertically moved up and down via the gap 14 In a pair. The lower first discharge gas nozzle 33 is disposed inside the folded-back portion 9a of the PMMA film 9. The upper first discharge gas nozzle 34 is disposed between the roller electrodes 11 and 12 on the upper side of the gap 14. The first discharge gas nozzles 33 and 34 extend long in the processing width direction, and the cross sections orthogonal to the extending direction are tapered toward the opposite sides of each other. The discharge port at the front end of each of the first discharge gas nozzles 33, 34 faces the gap 14. The argon gas from the gas supply source 31 is uniformed in the processing width direction by the rectifying portion (not shown) in the first discharge gas nozzles 33 and 34, and is discharged from the first discharge gas nozzles 33 and 34. It is ejected to the gap 14. The jet stream is a gas stream uniformly distributed in the width direction of the treatment.

A temperature control path (not shown) is provided in the first discharge gas nozzles 33 and 34. The temperature control medium such as water passes through the temperature adjustment path in the first discharge gas nozzles 33, 34. Thereby, the first discharge gas nozzles 33 and 34 can be tempered, and the discharge temperature of the argon gas (first discharge gas) can be adjusted. The set temperatures of the first discharge gas nozzles 33 and 34 are preferably about 25 to 45 °C.

The second reaction gas supply mechanism 40 includes a supply source 41 of the second reaction gas and a second reaction gas nozzle 43. The second reaction gas contains the same gas as the first reaction gas. That is, the second reaction gas contains a polymerizable monomer and a carrier gas. Acrylic acid (AA) is used as a polymerizable single system. Nitrogen (N ₂ ) is used as the carrier gas system. The second reaction gas contains a mixed gas of acrylic acid and nitrogen.

Although the detailed illustration is omitted, the second reaction gas supply source 41 includes a vaporizer. In the gasifier, the liquid acrylic acid is vaporized in the carrier gas. Gasification can be either foaming or extrusion. The second reaction gas is produced by mixing the vaporized acrylic acid with a carrier gas. The first reaction gas supply source 21 and The second reaction gas supply source 41 may also include a common acrylic acid supply source.

The second reaction gas supply source 41 is connected to the second reaction gas nozzle 43 via the gas path 42 . The second reaction gas nozzle 43 is disposed above the second roller electrode 12. The second reaction gas nozzle 43 extends long in the processing width direction and has a certain width in the circumferential direction of the second roller electrode 12 (left and right in FIG. 1). A discharge port is provided on a lower surface of the second reaction gas nozzle 43. The discharge port is formed to be distributed over a wide range (process width direction and roll circumferential direction) of the lower surface of the second reaction gas nozzle 43. The discharge surface (lower surface) of the second reaction gas nozzle 43 faces the PMMA film 9 on the second roller electrode 12. The second reaction gas from the second reaction gas supply source 41 is supplied to the second reaction gas nozzle 43 and is uniformized by a rectifying unit (not shown) in the second reaction gas nozzle 43. Thereafter, the second reaction gas is supplied from the second reaction gas nozzle 43. The discharge port of the reaction gas nozzle 43 is ejected. The discharged gas stream of the second reaction gas is a gas stream uniformly distributed in the processing width direction.

A temperature adjustment mechanism (not shown) is provided in the gas path 42 and the second reaction gas nozzle 43. The temperature regulating mechanism of the gas path 42 includes a heating belt or the like. The temperature adjustment mechanism of the second reaction gas nozzle 43 includes a temperature adjustment path through which the temperature control water passes. The set temperatures of the gas path 42 and the second reaction gas nozzle 43 are higher than the condensation temperature of acrylic acid. Thereby, the acrylic acid can be prevented from being condensed before being ejected. The set temperature of the gas path 42 and the second reaction gas nozzle 43 is preferably about 60 to 80 °C.

A shielding member 44 is provided at the bottom of the second reaction gas nozzle 43. The shielding member 44 is formed in an arcuate cross section along the circumferential direction of the second roller electrode 12, and is substantially the same length as the roller electrode 12 in the processing width direction. The curved plate is extended. The shielding member 44 extends further in the circumferential direction of the second roller electrode 12 than the second reaction gas nozzle 43. In FIG. 1, the left end portion of the shield member 44 on the left side abuts or approaches the side portion of the first discharge gas nozzle 34. In FIG. 1, the right end portion of the shielding member 44 on the right side abuts or approaches the nozzle 54 described below.

A second spray space 45 is formed between the shield member 44 and the second roller electrode 12. The second injection space 45 is a space having an arcuate cross section along the circumferential surface of the upper side of the second roller electrode 12. By the shielding member 44, the second injection space 45 is extended toward both sides in the circumferential direction of the second roller electrode 12 from the second reaction gas nozzle 43. In FIG. 1, the end portion on the left side of the second spray space 45 is connected to the first discharge space 14 via a gap between the first discharge gas nozzle 34 and the roller electrode 12. In FIG. 1, the end portion on the right side of the second spray space 45 is connected to the gap 15 via a gap between the nozzle 54 and the roller electrode 12 described below.

The second discharge gas supply mechanism 50 includes a second discharge gas supply source 51 and second discharge gas nozzles 53 and 54. Argon (Ar) is stored as the second discharge generating gas in the second discharge gas supply source 51. The first discharge gas supply source 31 and the second discharge gas supply source 51 may also include a common argon gas supply source.

The gas path 52 from the gas supply source 51 is connected to the second discharge gas nozzles 53, 54. The second discharge gas nozzles 53 and 54 are vertically formed in a pair with a gap 15 interposed therebetween. The lower second discharge gas nozzle 53 is disposed inside the folded-back portion 9b of the PMMA film 9. The upper second discharge gas nozzle 54 is disposed between the roller electrodes 11 and 12 on the upper side of the gap 15. The second discharge gas nozzles 53 and 54 extend long in the processing width direction, and the cross sections orthogonal to the extending direction are tapered toward the opposite sides of each other. Each second discharge gas The discharge ports at the front ends of the nozzles 53, 54 face the gap 15. The argon gas from the gas supply source 51 is uniformed in the processing width direction by the rectifying portion (not shown) in the second discharge gas nozzles 53, 54, and is discharged from the second discharge gas nozzles 53, 54. It is ejected to the gap 15. The jet stream is a gas stream uniformly distributed in the width direction of the treatment.

A temperature control path (not shown) is provided in the second discharge gas nozzles 53, 54. The temperature control medium such as water passes through the temperature adjustment path in the second discharge gas nozzles 53, 54. Thereby, the second discharge gas nozzles 53, 54 can be tempered, and the discharge temperature of the argon gas (second discharge gas) can be adjusted. The set temperature of the second discharge gas nozzles 53, 54 is preferably about 25 ° C to 45 ° C.

A method of surface-treating the PMMA film 9 by the film surface treatment apparatus 1 configured as described above, or a method of manufacturing a polarizing plate will be described.

[Support steps, transfer steps]

The continuous sheet-shaped PMMA film 9 is wound around the roll electrodes 11 to 13 and the guide rolls 16, 17.

The roller electrodes 11 to 13 are rotated clockwise in FIG. 1, and the PMMA film 9 is conveyed in the substantially right direction in FIG. 1 in the order of the first roller electrode 11, the second roller electrode 12, and the third roller electrode 13. The transport speed is preferably from about 1 m/min to about 30 m/min.

[1st contact step]

In the first reaction gas supply unit 20, acrylic acid (AA) is vaporized in a carrier gas (N ₂ ) to generate a first reaction gas (AA+N ₂ ). The volume concentration of acrylic acid in the first reaction gas is preferably from 2% to 8%. This first reaction gas is discharged from the reaction gas nozzle 23 to the first spray space 25. The first reaction gas is brought into contact with the surface of the PMMA film 9 in the first spray space 25. Thereby, the acrylic monomer in the first reaction gas is condensed and adhered to the PMMA film 9, and a first condensed layer containing an acrylic monomer is formed on the surface of the PMMA film 9.

[First irradiation step]

As the first roller electrode 11 rotates, the portion of the PMMA film 9 that has passed through the first contact step is transported to the first discharge space 14 which is the gap 14. In the first discharge gas supply mechanism 30, argon is discharged as the first discharge gas from the first discharge gas nozzles 33 and 34 to the first discharge space 14. Argon may be ejected from the first and second first discharge gas nozzles 33 and 34, or argon may be ejected from only one of the first discharge gas nozzles 33 or 34. Preferably, argon is ejected from the lower first discharge gas nozzle 33. At the same time, electric power is supplied to the roller electrode 12, and a discharge in the vicinity of the atmospheric pressure is generated in the first discharge space 14, thereby argonizing the argon (first discharge gas). The argon plasma is brought into contact with the surface of the PMMA film 9 in the first discharge space 14. Thereby, the acrylic monomer of the first condensation layer is plasma-polymerized to form a first plasma polymerization film containing polyacrylic acid on the surface of the PMMA film 9. It is considered that the plasma density can be increased by using argon as a discharge gas, and the degree of polymerization of the first plasma polymerization film can be improved. The PMMA film 9 is folded back by the guide roller 16, whereby it reciprocates in the first discharge space 14, and is processed twice by the first discharge gas supply mechanism 30.

[2nd contact step]

Thereafter, the portion of the PMMA film 9 that has passed through the first irradiation step is transported to the second spray space 45 along with the second roller electrode 12. In the second reaction gas supply mechanism 40, acrylic acid (AA) is vaporized in the carrier gas (N ₂ ) to generate a second reaction gas (AA+N ₂ ). The volume concentration of acrylic acid in the second reaction gas is preferably from 2% to 8%. The acrylic acid concentration of the second reaction gas may be the same as the acrylic acid concentration of the first reaction gas, or may be higher than the acrylic acid concentration of the first reaction gas, or may be lower than the acrylic acid concentration of the first reaction gas. This second reaction gas is discharged from the second reaction gas nozzle 43 to the second injection space 45. The second reaction gas is brought into contact with the surface of the PMMA film 9 in the second spray space 45. The acrylic monomer in the second reaction gas is condensed and adhered to the PMMA film 9, and a second condensed layer containing an acrylic monomer is further formed on the first plasma polymerization film.

[2nd irradiation step]

As the second roller electrode 12 rotates, the portion of the PMMA film 9 that has passed through the second contact step is transported to the second discharge space 15 which is the gap 15. In the second discharge gas supply mechanism 50, argon is discharged as a second discharge gas from the second discharge gas nozzles 53 and 54 to the second discharge space 15. Argon may be ejected from the upper and lower second discharge gas nozzles 53, 54 or may be ejected from only one of the second discharge gas nozzles 53 or 54. Preferably, argon is ejected from the lower second discharge gas nozzle 53. In the second discharge space 15, a discharge near the atmospheric pressure is generated by the supply of electric power to the roller electrode 12, and argon (second discharge gas) is plasma-formed. The argon plasma is brought into contact with the surface of the PMMA film 9 in the second discharge space 15. Thereby, the polymerization degree of the first plasma polymerization film is further increased, and the acrylic monomer of the second condensation layer is plasma-polymerized to form a second layer containing polyacrylic acid on the first plasma polymerization film. Plasma polymer film. The adhesion promoting layer is formed by the first and second plasma polymerization films. The first plasma polymerization film not only promotes polymerization by the first irradiation step but also promotes polymerization by the second irradiation step, so the polymerization degree is higher than that of the second plasma polymerization. membrane. It is considered that the plasma density in the second discharge space 15 can be increased by using argon as the discharge gas in the second irradiation step, and the degree of polymerization of the first and second plasma polymerization films can be improved. The PMMA film 9 is folded back by the guide roller 16, thereby reciprocating in the second discharge space 15, and is processed twice by the second discharge gas supply mechanism 50. The PMMA film 9 reciprocated in the second discharge space is carried along the third roller electrode 13 and carried out from the apparatus 1.

The surface-treated PMMA film 9 was then passed through a PVA-based adhesive to a PVA film to prepare a polarizing plate. By performing the above surface treatment before the subsequent step, the adhesion strength of the PMMA film 9 and the PVA adhesive which are difficult to adhere can be improved, and the PMMA film 9 or the polarizing plate can be sufficiently improved when exposed to a high temperature and high humidity environment. The durability of the joint. In particular, by using a polymerizable monomer using acrylic acid as a reaction component and using argon as a discharge gas, the above-mentioned bonding strength and even durability can be surely improved. Regarding the durability, if the PMMA film is exposed to a high-temperature and high-humidity environment, the adhesion strength can be increased more than before the exposure (see Examples 1 to 4 below). Thereby, peeling of a polarizing plate can be prevented, and quality can be improved.

The present invention is not limited to the above embodiments, and various changes can be made without departing from the spirit and scope of the invention.

For example, the carrier gas of the first and second reaction gases is not limited to nitrogen (N ₂ ), and may be argon (Ar). The carrier gas may be the same component as the first and second discharge generating gases. In this case, even if the carrier gas (Ar) flows into the discharge spaces 14 and 15, the discharge state can be prevented from changing, and stable discharge can be maintained. Further, the carrier gas may be other rare gases such as helium or neon.

The first contact step and the first irradiation step can also be performed simultaneously. Can also omit gas The body nozzle 23 discharges the first reaction gas containing acrylic acid and argon from the gas nozzles 33 and 34 to the first discharge space 14. This argon also serves as a carrier gas for the first reaction gas and a first discharge generating gas.

The second contact step and the second irradiation step can also be performed simultaneously. The gas nozzle 43 may be omitted, and the second reaction gas containing acrylic acid and argon may be ejected from the gas nozzles 53, 54 to the second discharge space 15. This argon also serves as a carrier gas for the second reaction gas and a second discharge generation gas.

In the manufacturing steps of the polarizing plate, the PMMA film can also be exposed to a high temperature and high humidity environment. Thereby, the adhesion durability of the PMMA film can be improved.

It is also possible to arrange four or more roller electrodes, and perform three or more injections of a reaction gas containing acrylic acid and argon plasma irradiation. In this case, in the case of the reaction gas spray containing acryl and the argon plasma irradiation for two consecutive times, the first reaction gas containing acrylic acid is sprayed as the "first contact step", and the first argon plasma irradiation is "the first In the "irradiation step", the reaction gas containing acrylic acid is then sprayed as "second contact step", and the subsequent argon plasma irradiation is "second irradiation step".

[Example 1]

The examples are described below, but the present invention is not limited to the following examples.

An optical film (OP-PMMA) was used as the PMMA film 9. The width of the film 9 is 320 mm.

As a pretreatment, a mixed gas of N ₂ and O ₂ is plasma-treated and irradiated onto the PMMA film 9 to wash the surface of the film 9 (removal of organic impurities).

Next, the configuration is substantially the same as that of the surface treatment apparatus 1 of FIG. In the apparatus, the first contact step, the first irradiation step, the second contact step, and the second irradiation step are sequentially performed on the PMMA film 9. The dimensional configuration and processing conditions of the surface treatment apparatus 1 are as follows.

The axial length of the roller electrodes 11, 12, 13 in the processing width direction: 390 mm The diameter of the roller electrodes 11, 12, 13: 310 mm The power supplied to the roller electrode 12: 250 W (DC voltage 120 V × DC current 2.1 A) High-frequency conversion) Supply frequency: 50 kHz between the roller electrodes 11, 12 and between the roller electrodes 12, 13: Vpp = 6.5 kV PMMA film 9 transport speed: 20 m / min PMMA film 9 set temperature: 40 °C discharge temperature of first reaction gas (AA+N ₂ ): 75 ° C Flow rate of first reaction gas (AA+N ₂ ): 30 slm Volume concentration of acrylic acid in the first reaction gas: 7.8% from the first discharge gas Argon flow rate of the nozzle 33: 15 slm Argon flow rate from the first discharge gas nozzle 34: 0 slm Second reaction gas (AA+N ₂ ) ejection temperature: 75 ° C Flow rate of the second reaction gas (AA + N ₂ ): Volume concentration of acrylic acid in the 30 slm second reaction gas: 7.8% Argon flow rate from the second discharge gas nozzle 53: 15 slm Argon flow rate from the second discharge gas nozzle 54: 0 slm

A PVA-based adhesive was applied to the surface to be treated of the PMMA film 9 after the surface treatment, and bonded to the PVA film. As a PVA-based adhesive, use (A) An aqueous solution of a PVA 5 wt% aqueous solution having a degree of polymerization of 500 and (B) a sodium carboxymethylcellulose 2 wt% aqueous solution. The mixing ratio of (A) and (B) is set to (A): (B) = 20:1. The drying conditions of the subsequent agent were set to 80 ° C for 5 minutes.

Further, acrylic acid was sprayed on the TAC film, and N ₂ plasma was irradiated. The TAC film was bonded to the opposite side of the PVA film by the same PVA-based adhesive as described above. Thereby, a plurality of polarized plate samples having a three-layer structure were produced. The width of the polarizer sample is set to 25 mm.

[Initial strength]

After the PVA-based adhesive was cured, the adhesion strength of the PMMA film 9 and the PVA film (referred to as "initial adhesion strength") was measured for the polarizing plate sample which was not subjected to the wet heat treatment described below. The measurement method is based on the floating roll method (JIS K6854). As a result, the average is 2.9 N/inch.

[durable bonding strength]

For the remaining polarizer samples, after the PVA adhesive was hardened, a wet heat treatment was performed. The inside of the wet heat treatment tank was set to a high temperature and high humidity environment of 60 ° C and 95% RH, and the polarizing plate sample was left in the wet heat treatment tank for 1 hour. Thereafter, the polarizing plate sample was taken out from the wet heat treatment tank and cooled at room temperature for 3 minutes. Then, the bonding strength (referred to as "durable bonding strength") of the PMMA film 9 and the PVA film was measured by a floating roll method (JIS K6854) having the same initial adhesion strength as described above. As a result, the material broke at 8.4 N/inch. Therefore, the PMMA film is exposed to a hot and humid environment and the strength is instead increased.

Further, in Example 1, the surface treatment of the PMMA film 9, the preparation of the polarizing plate sample, and the evaluation (initial strength measurement and durability bonding strength measurement) were all performed on the same day.

[Embodiment 2]

In Example 2, the acrylic acid concentration in the first reaction gas was 5.8%, and the acrylic acid concentration in the second reaction gas was 5.8%. The other conditions are the same as in the first embodiment. The procedure for preparing the polarizing plate sample after the surface treatment, and the measurement procedure for the initial adhesion strength and the durability bonding strength were the same as in the first embodiment. The initial strength was an average of 1.8 N/inch. The material broke at 8.4 N/inch in the measurement of durable bond strength.

[Example 3]

In Example 3, the transport speed of the PMMA film 9 was set to 10 m/min. The other conditions are the same as in the second embodiment. The procedure for preparing the polarizing plate sample after the surface treatment and the measurement procedure for the initial adhesion strength and the durability bonding strength were the same as in Examples 1 and 2. The initial strength was 2.9 N/inch on average. The material fractured at 8.7 N/inch in the measurement of durable bond strength.

According to the results of Examples 1 to 3, it was confirmed that the initial adhesion strength can be adjusted by setting the acrylic acid concentration in the first and second reaction gases or setting the transport speed. That is, the initial adhesion strength can be improved by increasing the concentration of acrylic acid or retarding the conveyance speed. Moreover, the durability adhesive strength can be sufficiently improved regardless of the acrylic acid concentration and the transport speed.

[Example 4]

In Example 4, the surface treatment of PMMA film 9 (OP-PMMA) was carried out under the same conditions as in Example 1. The surface-treated PMMA film 9 was wound into a roll and left at room temperature for 38 days. Then, a polarizing plate sample was prepared in the same procedure as in Example 1, and the initial bonding strength and durability were measured. Strength. The initial strength was 2.8 N/inch on average. The material was broken at 9.9 N/inch in the measurement of durable bond strength.

It was confirmed that the change with time after the surface treatment was hardly produced.

Table 1 summarizes the main processing conditions and evaluations of Examples 1 to 4.

[Comparative Example 1]

As Comparative Example 1, a polarizing plate sample was prepared for the PMMA film 9 (OP-PMMA) which was not subjected to the above surface treatment, and the initial adhesion strength and the durability bonding strength were measured. The procedure for preparing the polarizing plate sample and the measurement procedure for the initial adhesion strength and the durability bonding strength were the same as in the first embodiment. The initial strength was an average of 0.4 N/inch. The durability strength is an average of 0.5 N/inch.

[Comparative Example 2]

In Comparative Example 2, in the surface treatment of the PMMA film 9 (OP-PMMA), the second contact step and the second irradiation step were omitted, and only the first contact step and the first irradiation step were performed. The surface treatment conditions, the preparation procedure of the polarizing plate sample, and the measurement procedure of the initial adhesion strength and the durability bonding strength were the same as in the first embodiment. The initial strength was an average of 1.2 N/inch. The durable bond strength averaged 2.7 N/inch.

According to the results of the above embodiments and Comparative Example 2, it can be confirmed that by repeating Acrylic spray and argon plasma irradiation can improve initial adhesion strength and durability.

[Comparative Example 3]

As Comparative Example 3, nitrogen (N ₂ ) was used as the first and second discharge generating gases. The surface treatment conditions other than the above include the flow rates of the first and second discharge generating gases, and are the same as in the first embodiment. The procedure for preparing the polarizing plate sample and the measurement procedure for the initial adhesion strength and the durability bonding strength were the same as in the first embodiment. The initial strength was an average of 1.3 N/inch. The durability strength is 6.3 N/inch on average.

From the results of the above examples and Comparative Example 3, it was confirmed that the initial adhesion strength and the durable bonding strength can be improved by using argon as the discharge generating gas.

[Comparative Example 4]

In Comparative Example 4, the second contact step and the second irradiation step in Comparative Example 3 were omitted, and only the first contact step and the first irradiation step were performed. The surface treatment conditions, the procedure for preparing the polarizing plate sample, and the measurement procedure for the initial adhesion strength and the durability bonding strength were the same as in Comparative Example 3. The initial strength was an average of 1.2 N/inch. The durability strength is an average of 1.6 N/inch.

[Comparative Example 5]

In the above Examples 1 to 4 and Comparative Examples 1 to 4, OP-PMMA was used as the PMMA film. However, in the following Comparative Examples 5 to 7, OS-PMMA manufactured by Sekisui Chemical Co., Ltd. was used as the PMMA film. In Comparative Example 5, a PMMA film (OS-PMMA manufactured by Sekisui Chemical Co., Ltd.) which was not subjected to surface treatment was used to prepare a polarizing plate sample, and the initial measurement was performed. Then strength and durability followed by strength. The procedure for preparing the polarizing plate sample and the measurement procedure for the initial adhesion strength and the durability bonding strength were the same as in the first embodiment. The initial strength was an average of 0.4 N/inch. The durability strength is an average of 0.5 N/inch.

[Comparative Example 6]

In the surface treatment of the PMMA film (OS-PMMA manufactured by Sekisui Chemical Co., Ltd.), the second contact step and the second irradiation step were omitted, and only the first contact step and the first irradiation were performed. step. The surface treatment conditions, the preparation procedure of the polarizing plate sample, and the measurement procedure of the initial adhesion strength and the durability bonding strength were the same as in the first embodiment. The initial strength was an average of 2.7 N/inch. The durable bond strength averaged 4.8 N/inch.

[Comparative Example 7]

In Comparative Example 7, nitrogen (N ₂ ) was used as the first discharge generating gas in Comparative Example 6. The processing conditions other than the above include the flow rate of the first discharge generating gas as in Comparative Example 6. The procedure for preparing the polarizing plate sample and the measurement procedure for the initial adhesion strength and the durability bonding strength were the same as in the first embodiment. The initial strength was an average of 2.7 N/inch. The durable bond strength averaged 4.8 N/inch.

Table 2 summarizes the main processing conditions and evaluations of Comparative Examples 1 to 7. The "single" in the column of "processing number" in Table 2 indicates that only the first contact step and the first irradiation step are performed as the surface treatment step, and "twin" indicates that the first contact step and the first irradiation step are performed, and The second contact step and the second irradiation step serve as a surface treatment step.

[Industrial availability]

The present invention can be applied to a polarizing plate such as a flat panel display (FPD).

1‧‧‧ Film surface treatment device

9‧‧‧Processed film (PMMA film)

10‧‧‧Electrode construction

11‧‧‧1st roller electrode

12‧‧‧2nd roller electrode

13‧‧‧3rd roller electrode

14‧‧‧ gap, first discharge space

15‧‧‧ gap, second discharge space

16‧‧‧guide roller

17‧‧‧guide roller

20‧‧‧1st reaction gas supply mechanism

21‧‧‧1st reactive gas supply source

22‧‧‧ gas road

23‧‧‧1st reaction gas nozzle

24‧‧‧Shielding members

25‧‧‧1st spray space

30‧‧‧1st discharge gas supply mechanism

31‧‧‧1st discharge gas supply source

32‧‧‧ gas road

33‧‧‧1st discharge gas nozzle on the lower side

34‧‧‧1st discharge gas nozzle on the upper side

40‧‧‧2nd reaction gas supply mechanism

41‧‧‧2nd reactive gas supply source

42‧‧‧ gas road

43‧‧‧2nd reaction gas nozzle

44‧‧‧Shielding members

45‧‧‧2nd spray space

50‧‧‧2nd discharge gas supply mechanism

51‧‧‧2nd discharge gas supply source

52‧‧‧ gas road

53‧‧‧2nd discharge gas nozzle on the lower side

54‧‧‧Second discharge gas nozzle on the upper side

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

Fig. 2 is a perspective view showing an electrode portion and a nozzle portion of the surface treatment apparatus.

1‧‧‧ Film surface treatment device

9‧‧‧Processed film (PMMA film)

9a‧‧‧Return part

9b‧‧‧return part

10‧‧‧Electrode construction

11‧‧‧1st roller electrode

12‧‧‧2nd roller electrode

13‧‧‧3rd roller electrode

14‧‧‧ gap, first discharge space

15‧‧‧ gap, second discharge space

16‧‧‧guide roller

17‧‧‧guide roller

20‧‧‧1st reaction gas supply mechanism

21‧‧‧1st reactive gas supply source

22‧‧‧ gas road

23‧‧‧1st reaction gas nozzle

24‧‧‧Shielding members

25‧‧‧1st spray space

30‧‧‧1st discharge gas supply mechanism

31‧‧‧1st discharge gas supply source

32‧‧‧ gas road

33‧‧‧1st discharge gas nozzle on the lower side

34‧‧‧1st discharge gas nozzle on the upper side

40‧‧‧2nd reaction gas supply mechanism

41‧‧‧2nd reactive gas supply source

42‧‧‧ gas road

43‧‧‧2nd reaction gas nozzle

44‧‧‧Shielding members

45‧‧‧2nd spray space

50‧‧‧2nd discharge gas supply mechanism

51‧‧‧2nd discharge gas supply source

52‧‧‧ gas road

53‧‧‧2nd discharge gas nozzle on the lower side

54‧‧‧Second discharge gas nozzle on the upper side

Claims (2)

A film surface treatment method for treating a surface of a resin film containing polymethyl methacrylate as a main component (hereinafter referred to as "PMMA film"); and comprising the following steps: a first contacting step of contacting the first reaction gas obtained by vaporizing acrylic acid in a carrier gas into contact with the PMMA film; and the first irradiation step is performed after the first contacting step or simultaneously with the first contacting step The argon plasma generated near the atmospheric pressure is irradiated to the PMMA film, and the second contacting step is performed after the first irradiation step, and the second reaction gas obtained by vaporizing acrylic acid in the carrier gas contacts the PMMA. And a second irradiation step of irradiating the PMMA film to the PMMA film after the second contacting step or simultaneously with the second contacting step, the argon plasma generated under the atmospheric pressure. A film surface treatment apparatus characterized in that it processes a surface of a PMMA film; and comprises: first, second, and third roller electrodes arranged in parallel with each other and in a gap between adjacent ones a discharge is generated in the vicinity of the internal atmospheric pressure; the first reaction gas nozzle faces the peripheral surface of the first roller electrode to eject a first reaction gas containing acrylic acid; and the first discharge gas nozzle ejects argon to the first roller electrode and a second reaction gas nozzle that discharges a second reaction gas containing acrylic acid toward a circumferential surface of the second roller electrode; and a second reaction gas nozzle; a second discharge gas nozzle that ejects argon into a gap between the second roller electrode and the third roller electrode; and the PMMA film is wound around the first, second, and third roller electrodes, and The PMMA film is transferred in the order of the first roller electrode, the second roller electrode, and the third roller electrode in synchronization with the rotation of the first, second, and third roller electrodes.