JP4603348B2 - Method for hydrophilic treatment of polymer film surface, polymer film obtained thereby, and polarizing plate using the same - Google Patents

Description

  The present invention relates to a method for hydrophilizing a polymer film surface used for, for example, a protective film for a polarizing plate of a liquid crystal display, a polymer film obtained thereby, and a polarizing plate obtained using the same. is there.

  In recent years, liquid crystal displays have been used in various fields, and accordingly, high reliability has been demanded for polarizing plates constituting liquid crystal displays.

  As such a polarizing plate, a protective film is laminated on both surfaces of a polarizing film obtained by coloring and stretching a polyvinyl alcohol (PVA) film with iodine or the like, and further, On one side of the protective film, one having a hard coat layer formed for the purpose of increasing the surface hardness against the outside and protecting the polarizing plate is used. As the protective film, for example, a triacetyl cellulose (TAC) film has been widely used.

However, since the TAC film exhibits so-called hydrophobicity, there is a problem of poor adhesion between the protective film and the adhesive layer when adhering to the polarizing film via the adhesive layer. This is one of the causes of decline. From such a viewpoint, in order to improve the adhesion to the adhesive layer, the surface of the protective film is hydrophilized. For example, a method of modifying the film surface by applying a solvent to the surface of the protective film, or applying a solvent to the surface of the protective film, or applying an electron beam irradiation treatment to the surface of the protective film, followed by a chemical alkali treatment (saponification treatment) There has been proposed a modification method for making the surface of the protective film hydrophilic by carrying out the process (see Patent Document 1). Furthermore, a method of hydrophilizing the surface of the protective film by plasma treatment in an oxygen gas-containing atmosphere has been proposed (see Patent Document 2).
JP 2004-109713 A JP 2002-226616 A

  However, in the method of applying a solvent to the surface of the protective film, there arises a problem that the flatness of the protective film is deteriorated due to the influence of drying unevenness after the solvent is applied. Moreover, the method of performing the chemical alkali treatment (saponification treatment) after the electron beam irradiation treatment requires a long time for the treatment process, resulting in poor productivity, and a large amount of treatment waste liquid is generated, causing an environmental burden. Have problems such as. And, in the method of plasma treatment under the above oxygen gas-containing atmosphere, the surface of the protective film is made hydrophilic to some extent, but it has not reached the level to satisfy the recent high reliability requirement, The reality is that a higher level of satisfaction is required.

  The present invention has been made in view of such circumstances, and a method for hydrophilizing a polymer film surface capable of imparting excellent adhesion by hydrophilizing the surface, a polymer film obtained thereby, and the same It is an object to provide a highly reliable polarizing plate using

In order to achieve the above-described object, the present invention provides a device in which an object to be processed is disposed between opposing electrodes, and a polymer film is disposed in an atmospheric pressure plasma generator that performs treatment with atmospheric pressure plasma. The surface of the polymer film is hydrophilized by atmospheric pressure plasma generated therein, wherein the polymer film is a triacetyl cellulose film, and the F ₂ gas concentration is 0.1% of the total atmospheric gas. 2.0 There line treatment with atmospheric pressure plasma in an atmosphere gas within a range of volume%, the hydrophilic treatment method of a polymer film surface water contact angle of the surface to obtain a polymer film is 25 ° or less first It is set as the summary of 1.

  Moreover, this invention makes the 2nd summary the polymer film by which the film surface is hydrophilized by the said hydrophilic treatment method of the polymer film surface.

  Furthermore, the present invention is a polarizing plate in which a protective film is laminated on both surfaces of a polarizing film via an adhesive layer, and the protective film is a polarizing plate in which the polymer film is the third gist. .

That is, the present inventors have repeated a series of studies on a method that can impart excellent adhesion by hydrophilizing a conventionally used polymer film surface that exhibits hydrophobicity. As a result, when the surface of the polymer film is treated with atmospheric pressure plasma in an atmospheric gas containing a specific concentration of F ₂ gas, the surface of the polymer film is highly hydrophilized, and the adhesive layer forming material, etc. It has been found that the adhesion with the object to be adhered is improved and the adhesion to the polymer film is excellent, and the present invention has been achieved.

As described above, according to the method for hydrophilizing a polymer film surface of the present invention, the polymer is generated by atmospheric pressure plasma generated in an atmospheric pressure plasma generator under an atmospheric gas containing F ₂ gas at a specific concentration. The film surface is highly hydrophilized. As a result, the adhesion with the object to be adhered is improved. For example, when a polymer film is laminated as a protective film on a polarizing film via a water-soluble adhesive layer during the production of a polarizing plate, Excellent adhesion will be imparted. Accordingly, a highly reliable polarizing plate obtained by laminating the polymer film, which is a protective film having improved adhesion and improved hydrophilicity, can be obtained. The polymer film obtained by hydrophilizing the polymer film surface according to the present invention is useful in various forms of use of the polymer film in various fields. In addition to the polarizing plate protective film, the polymer film is flexible. It is applied to various films such as films for printed wiring boards.

Then, to set the F ₂ gas concentration in the range of 0.1 to 2.0% by volume of the total atmosphere gas, even more hydrophilic advanced polymer film surface is made improvement in adhesion to implement.

Moreover, since a TAC film is used as the polymer film, the hydrophilization effect becomes more prominent.

  Next, embodiments of the present invention will be described in detail.

In the hydrophilic treatment method of the polymer film surface of the present invention, the film material to be hydrophilized, in consideration of the characteristics of such parent hydration treatment effect, Ru is used is TAC film.

  Next, the method for hydrophilizing the polymer film surface of the present invention will be described with reference to the drawings.

  FIG. 1 shows an embodiment of a method for hydrophilizing a polymer film surface according to the present invention. In this embodiment, the polymer film G is placed in an atmospheric pressure plasma generator, atmospheric pressure plasma is generated in the device, and the surface of the polymer film G is hydrophilized by the atmospheric pressure plasma. I am doing so. In addition, in this invention, the atmospheric pressure in an atmospheric pressure plasma generator specifically means the pressure of 60000-210000Pa. In particular, in the atmospheric pressure plasma generation apparatus of the present invention, it is preferable to set the pressure in the apparatus during the hydrophilization treatment to a range of 93,000 to 107000 Pa.

  More specifically, the atmospheric pressure plasma generator includes an electrode that is a pair of a high voltage electrode 1 and a low voltage electrode 2 facing each other with a space therebetween, and a space between the high voltage electrode 1 and the low voltage electrode 2. The polymer film G can be disposed on at least a part of the film. The high-voltage electrode 1 and the low-voltage electrode 2 are usually made of metal, and it is necessary to provide dielectrics 5 on at least one of these opposing surfaces in order to sustain discharge in a stable state. As the metal forming the high-voltage electrode 1 and the low-voltage electrode 2, general-purpose metals such as silver, platinum, stainless steel, aluminum, and iron are used. The dielectric 5 is usually provided by coating a metal, and the materials thereof are silicate glass, borate glass, phosphate glass, germanate glass, telluric acid. Salt glass, aluminate glass, vanadate glass, or the like can be used. The high-voltage electrode 1 and the low-voltage electrode 2 are both flat-plate electrodes in FIG. 1. However, the present invention is not limited to this. For example, one or both electrodes may be cylindrical electrodes, square electrodes, You may use the shape of a columnar electrode and a roll-shaped electrode. The atmospheric pressure plasma generator includes an inlet 3 for filling a gas used for the atmospheric plasma and an outlet 4 for discharging the gas used therefor.

In the present invention, as the gas used for the atmospheric pressure plasma, an atmospheric gas (mixed gas) containing F ₂ gas as an essential component is used. As a mixed gas containing the F ₂ gas as an essential component, for example, the F ₂ gas as essential components, consisting of helium, neon, argon, krypton, xenon, radon and nitrogen as the base gas to which the generating plasma A mixed gas in which at least one inert gas selected from an inert gas group is mixed is used. Among these, from the viewpoints of handleability and discharge stability, it is particularly preferable to use an atmosphere gas (mixed gas) composed of He and F ₂ using He together with F ₂ gas.

Furthermore, the F ₂ gas concentration in the atmospheric gas is set in a range of 0.1 to 2.0% by volume of the entire atmospheric gas. Particularly preferred is 0.1 to 1.0% by volume of the whole atmospheric gas. That is, if it is less than 0.1% by volume, the F ₂ gas concentration is too low, and the hydrophilic treatment on the surface of the polymer film G is not sufficiently performed, and it is difficult to obtain a desired effect (improvement of adhesion). This is because when the amount exceeds 2.0% by volume, a tendency of water repellency is observed.

For this reason, as an atmospheric gas containing F ₂ gas as an essential component, specifically, He / F ₂ (volume%) = 98/2 to 99.9 / 0.1 is set. It is particularly preferable to use a mixed gas of

And the said polymer film G can be hydrophilized as follows, for example. That is, the polymer film G is prepared, and first, dust or the like on the surface of the polymer film G is removed by blowing air on the surface of the polymer film G as necessary. Next, the polymer film G is disposed in a space between the high-pressure electrode 1 and the low-pressure electrode 2 of the atmospheric pressure plasma generator, and filled with a mixed gas (atmospheric gas) containing the F ₂ gas as an essential component. Next, a voltage is applied between the high voltage electrode 1 and the low voltage electrode 2 to generate atmospheric pressure plasma. And this atmospheric pressure plasma introduce | transduces a fluorine atom into the surface of the said polymer film G, and the new functional group peculiar to a fluorine is formed (XPS analysis, the XIS-HSi apparatus made from KRATOS). In this way, the surface of the polymer film G is hydrophilized, and as a result, the adhesion is improved.

  In the generation of the atmospheric pressure plasma, the voltage applied between the high voltage electrode 1 and the low voltage electrode 2 is not particularly limited as long as the atmospheric pressure plasma is generated, but is usually in the range of 1 kV to 10 kV. Further, the frequency of the power source is not particularly limited as long as atmospheric pressure plasma is generated, but it is usually in the range of 1 kHz to 150 MHz, but may be a higher GHz band. However, the range of 1 kHz to 500 kHz is preferable in consideration of the influence of heat of the workpiece.

The time for generating atmospheric pressure plasma (the time for hydrophilization treatment) is usually 3 seconds or more, although it depends on other conditions such as the concentration of F ₂ gas in the atmospheric gas containing F ₂ gas as an essential component. It is preferable to set to be in the range of 3 to 180 seconds.

  In the present invention, as a result of the hydrophilic treatment of the surface of the polymer film G by atmospheric pressure plasma as described above, the film surface is modified to have a water contact angle of 25 ° or less, for example. In the hydrophilization treatment of the present invention, the lower limit value of the water contact angle after the hydrophilization treatment for the polymer film G is 1 °. The water contact angle is one of characteristic values indicating the degree of hydrophobicity of the polymer film G that is a solid, and is a value measured according to JIS R32576. For example, the contact angle measuring device Is measured. Therefore, the smaller this value is, the more hydrophilic it is. For example, when used as a protective film for a polarizing plate, the adhesiveness with an adhesive layer described later, and further the adhesiveness with a hard coat layer. Means good.

  Therefore, for example, when preparing a polarizing plate using the polymer film G as a protective film for a polarizing plate, when the protective film as the polymer film G is adhesively laminated on both surfaces of the polarizing film via an adhesive layer, the polymer Adhesiveness between the protective film as the film G and the adhesive layer is improved. As a result, the adhesiveness to the polarizing film is improved and a highly reliable polarizing plate is obtained. In addition, a hard coat layer is usually formed on one side of the protective film to be laminated, and even when this hard coat layer is formed, the adhesion of both is improved by the hydrophilic treatment of the polymer film that is the protective film. Become. In addition, the hydrophilic treatment by atmospheric pressure plasma of the present invention does not require a chemical solution treatment step as in the prior art, so the process is not complicated and productivity is improved, and there is also a problem of environmental burden due to generation of waste liquid. Does not occur.

  Moreover, in the said embodiment, although the hydrophilic treatment by atmospheric pressure plasma arranged the polymer film G between the high voltage electrode 1 and the low voltage electrode 2 which oppose, it is not limited to this, Hydrophilic treatment by a method (remote plasma) in which atmospheric pressure plasma generated between the electrodes is blown out to a predetermined portion of the surface of the polymer film G arranged outside the electrodes by the action of gas flow, electric field arrangement or magnetism May be.

  As an example of the embodiment of the polymer film G having a hydrophilic surface as described above, a case where it is used for a protective film for a polarizing plate will be described. That is, by using as a protective film for a polarizing plate (hereinafter referred to as “protective film”), adhesion with an object is improved and a highly reliable polarizing plate is produced. An example of the configuration of the polarizing plate in the present invention will be described with reference to the drawings. That is, as shown in FIG. 2, the polarizing plate 15 is formed by laminating a protective film G (polymer film G subjected to hydrophilic treatment) on both surfaces of the polarizing film 11 with the adhesive layer 12 interposed therebetween. . A primer layer (not shown) is appropriately provided on one surface of the protective film G, and a hard coat layer 14 is further formed through the primer layer.

  Although it does not specifically limit as said polarizing film 11, A PVA-type film, an ethylene vinyl alcohol-type film, a cellulose-type film, a polycarbonate-type film etc. are mention | raise | lifted, Especially, a PVA-type film is suitable.

  The PVA is usually produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate, but is not necessarily limited thereto, and a small amount of unsaturated carboxylic acid (including salt, ester, amide, nitrile, etc.) Further, it may contain a component copolymerizable with vinyl acetate such as olefins, vinyl ethers and unsaturated sulfonates. The average saponification degree in the PVA is practically 85 to 100 mol%. Moreover, although arbitrary things can be used as an average degree of polymerization of the said PVA, 1500-5000 are advantageous.

  The material for forming the adhesive layer 12 is not particularly limited and may be a conventionally known material such as PVA resin (including PVA modified with acetoacetyl group, sulfonic acid group, carboxyl group, oxyalkylene group, etc.). ), An aqueous solution of a boron compound or the like is appropriately employed, and among them, a PVA resin, particularly an aqueous solution of PVA is preferably used. As this PVA, those having an average degree of polymerization of 500 to 4000 and a degree of saponification of 90.0 to 99.9 mol% are preferably used. Further, the concentration of the aqueous solution is preferably about 0.1 to 15% by weight.

  The material for forming the primer layer provided between the hard coat layer 14 and the protective film G when forming the hard coat layer 14 is not particularly limited, and various conventionally known materials such as (meth) acrylic Polymers, styrene polymers, polyesters and the like are preferably used. The monomer unit that can be used is not particularly limited. Specifically, the (meth) acrylic polymer includes (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, butyl. (Meth) acrylate, (meth) allyl acrylate, (meth) urethane acrylate, 2-hydroxyethyl (meth) acrylate, and the like. Examples of the styrenic polymer include styrene, divinylbenzene, vinyltoluene, α-methylstyrene, and the like. Examples of the polyester include condensates of ethylene glycol, propylene glycol, diethylene glycol and phthalic anhydride, phthalic acid, terephthalic acid, maleic anhydride, maleic acid, and the like.

  The material for forming the hard coat layer 14 is not particularly limited, and various conventionally known materials such as ultraviolet rays (UV) such as acrylate-based paints, urethane-acrylate-based paints, epoxy-acrylate-based paints, and polyester acrylate-based paints. Examples thereof include thermosetting paints such as curable paints, urethane paints, alkyd paints, and melamine paints, and silicone paints.

  The manufacturing method of the polarizing plate 15 having such a configuration will be specifically described.

  The polarizing film 11 can be obtained, for example, by casting and forming a stock solution in which PVA is dissolved in a solvent, followed by stretching, dyeing, and boron compound treatment.

  Examples of the solvent used for preparing the stock solution include water, dimethyl sulfoxide (DMSO), N-methylpyrrolidone, glycerin, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylolpropane, and the like. Solvents such as polyhydric alcohols and amines such as ethylenediamine and diethylenetriamine are used. These may be used alone or in combination of two or more. For example, a small amount of water of 5 to 30% by weight may be contained in the solvent. Moreover, as a density | concentration of PVA in a stock solution, 5 to 20 weight% is practical.

  The method for forming the stock solution is not particularly limited, and examples thereof include arbitrary methods such as a casting method and an extrusion method. Specifically, it is not performed by a dry / wet film-forming method, that is, by discharging the stock solution from the base slit into the air or an inert atmosphere such as nitrogen, helium, or argon, and then introducing it into a coagulation bath. A stretched film is obtained. In addition, the film-forming stock solution discharged from the die may be partially dried on a roller, a belt conveyor or the like and then introduced into the coagulation bath. In addition, a so-called gel film forming method in which a PVA undiluted solution is introduced into a coagulation bath to form a film can be performed.

  The solvent used in the coagulation bath is not particularly limited as long as it is miscible with the PVA solvent, and examples thereof include alcohols such as methanol, ethanol, propanol, and butanol, acetone, benzene, toluene, and the like. It is done.

  Next, the PVA unstretched film obtained as described above is subjected to stretching, dyeing, and boron compound treatment. In this case, stretching, dyeing, and boron compound treatment may be performed separately or simultaneously. For example, the PVA unstretched film is stretched and immersed in an aqueous solution of iodine or dichroic dye and dyed, or stretched and dyed simultaneously, or dyed with iodine or dichroic dye and stretched. Thereafter, a method of treating with a boron compound can be mentioned. In addition, there is a method of stretching in a solution of a boron compound after dyeing, etc., which can be appropriately selected and used.

  The stretching is preferably performed 3.5 to 10 times in a uniaxial direction. At this time, the film may be slightly stretched in the direction perpendicular to the above (stretching to prevent the axial shrinkage or more). The temperature condition at the time of stretching is usually appropriately selected within the range of 40 to 130 ° C. Furthermore, the stretching ratio may be finally set within the above range, and the stretching operation may be performed not only in one stage but also in any stage of the manufacturing process.

  The stretching is preferably performed so that the film thickness of the stretched film is 20 μm or less, particularly preferably 15 to 20 μm.

  In addition, as a raw film of PVA before extending | stretching, the film thickness is 30-100 micrometers normally, Preferably it is 50-90 micrometers. That is, if it is less than 30 μm, it may be impossible to stretch, while if it exceeds 100 μm, the film thickness accuracy may be lowered and may be inappropriate.

  The iodine dyeing of the film is usually performed by bringing an iodine-potassium iodide aqueous solution into contact with the film. In this case, the iodine concentration is suitably 0.1-2 g / l, the potassium iodide concentration is 10-50 g / l, and the iodine / potassium iodide weight ratio is suitably iodine / potassium iodide = 20-100. . The dyeing time is practically about 30 to 500 seconds, and the temperature of the treatment bath is preferably 5 to 50 ° C. In addition to the aqueous solution, a small amount of an organic solvent compatible with water may be contained. As the contact means, any means such as dipping, coating, spraying and the like can be applied.

  The film thus dyed is then treated with a boron compound such as boric acid or borax. The boron compound is used in the form of an aqueous solution or a water-organic solvent mixture at a concentration of about 0.5 to 2 mol / liter, and it is practically preferable that a small amount of potassium iodide coexists in the solution. The concentration of potassium iodide is set to about 30 to 70 g / liter. The treatment method is preferably an immersion method, but of course, an application method and a spray method can also be carried out. Furthermore, the temperature during the treatment is preferably about 40 to 70 ° C., and the treatment time is preferably about 5 to 20 minutes.

  On the other hand, the adhesive layer 12 forming material is applied so as to form a uniform film on one surface of the protective film G whose surface is hydrophilized, and the adhesive layer 12 is formed to form the protective film G. Two types of film-like bodies having the adhesive layer 12 formed on one side are produced. At this time, a primer layer is applied and formed on one film-like body on the surface opposite to the surface on which the adhesive layer 12 is formed, and then the hard coat layer 14 is formed. In application using the adhesive layer 12 forming material, it is practical that the thickness after drying is 0.01 to 10 μm. That is, when the thickness is less than 0.01 μm, the adhesive strength is insufficient. On the other hand, when the thickness exceeds 10 μm, the effect does not increase for the amount used, and the appearance deteriorates and is not practical. Application | coating operation is not necessarily limited to the application means using a roll etc., Means, such as a spray method and a dipping method, are applicable.

  Next, each protective film G in which the adhesive layer 12 is formed using the adhesive layer 12 forming material is bonded and bonded to both surfaces of the polarizing film 11 obtained by the above-described treatment via the adhesive layer 12. Then, the polarizing plate 15 which the protective film G adhered firmly to both surfaces of the polarizing film 11 by performing heat processing for 1 to 20 minutes at 40-100 degreeC is obtained. In this way, a polarizing plate 15 as shown in FIG. 2 can be obtained.

  As the polarizing plate 15 of the present invention thus obtained, the thickness of the polarizing film 11 is preferably 50 to 300 μm. The thickness of the adhesive layer 12 is preferably 0.01 to 10 μm. Further, the thickness of the protective film G is preferably 10 to 200 μm. Further, the thickness of the hard coat layer 14 is preferably 0.5 to 15 μm.

  Next, examples will be described together with comparative examples.

In the same manner as in the above embodiment (see FIG. 1), a TAC film (Konica Corporation, Konicatak 4UX) to be a polymer film G is converted into an atmospheric pressure plasma processing apparatus (Air Water, AP-70TF-SI). Was hydrophilized with atmospheric pressure plasma. In this hydrophilization treatment, the size of the TAC film G for hydrophilizing the surface was 70 mm wide × 40 μm thick. Further, a mixed gas consisting of He / F ₂ (volume%) = 99.9 / 0.1 was used as the atmospheric gas used for the atmospheric pressure plasma. The conditions in the atmospheric pressure plasma generator include an AC power source having a frequency of 30 kHz as a power source, a voltage of 10 kV applied between the high voltage electrode 1 and the low voltage electrode 2 (distance between electrodes: 3 mm), and atmospheric pressure plasma. The hydrophilization treatment step was performed for 30 seconds. The pressure in the atmospheric pressure plasma generator was 102000 Pa.

As the atmospheric gas used for the atmospheric pressure plasma, a mixed gas consisting of He / F ₂ (volume%) = 99.7 / 0.3 was used. Moreover, the hydrophilization treatment process by atmospheric pressure plasma was made into 3 second. Other than that, it was the same as in Example 1 above.

As the atmospheric gas used for the atmospheric pressure plasma, a mixed gas consisting of He / F ₂ (volume%) = 99.7 / 0.3 was used. Moreover, the hydrophilization treatment process by atmospheric pressure plasma was made into 30 seconds. Other than that, it was the same as in Example 1 above.

As the atmospheric gas used for atmospheric pressure plasma, a mixed gas consisting of He / F ₂ (volume%) = 99.0 / 1.0 was used. Moreover, the hydrophilization treatment process by atmospheric pressure plasma was made into 3 second. Other than that, it was the same as in Example 1 above.

As the atmospheric gas used for atmospheric pressure plasma, a mixed gas consisting of He / F ₂ (volume%) = 99.0 / 1.0 was used. Moreover, the hydrophilization treatment process by atmospheric pressure plasma was made into 30 seconds. Other than that, it was the same as in Example 1 above.

As the atmospheric gas used for atmospheric pressure plasma, a mixed gas consisting of He / F ₂ (volume%) = 99.0 / 1.0 was used. Moreover, the hydrophilization treatment process by atmospheric pressure plasma was made into 180 second. Other than that, it was the same as in Example 1 above.

As the atmospheric gas used for atmospheric pressure plasma, a mixed gas consisting of He / F ₂ (volume%) = 98.0 / 2.0 was used. Moreover, the hydrophilization treatment process by atmospheric pressure plasma was made into 30 seconds. Other than that, it was the same as in Example 1 above.

[Comparative Example 1]
As an atmospheric gas used for atmospheric pressure plasma, a mixed gas of Ar / He / CO ₂ / CH ₄ (volume%) = 47.5 / 47.5 / 1.1 / 3.9 was used. Other than that, it was the same as in Example 1 above.

[Comparative Example 2]
As the atmospheric gas used for the atmospheric pressure plasma, a mixed gas consisting of He / NF ₃ (volume%) = 99.0 / 1.0 was used. Other than that, it was the same as in Example 1 above.

[Comparative Example 3]
As the atmospheric gas used for the atmospheric pressure plasma, a mixed gas consisting of He / CF ₄ / O ₂ (volume%) = 89/9/2 was used. Other than that, it was the same as in Example 1 above.

[Comparative Example 4]
As the atmospheric gas used for atmospheric pressure plasma, a mixed gas consisting of He / CF ₄ (volume%) = 90/10 was used. Other than that, it was the same as in Example 1 above.

(Measurement of water contact angle)
And about each polymer film G hydrophilized by the said Examples 1-7 and Comparative Examples 1-4, the contact angle by the water of the film surface is made into a contact angle measuring apparatus (GL-700SQ made from Elma). It was measured by. In the present invention, it was evaluated that a water contact angle of 25 ° or less was sufficiently hydrophilized. The results are shown in Table 1 below together with the composition ratio of the atmospheric gas and the treatment time.

From the above results, all of the example products hydrophilized by atmospheric pressure plasma using a mixed gas containing F ₂ gas have a water contact angle of 22 ° or less, and a remarkable effect is obtained in the hydrophilization treatment. I understand that. In particular, in Examples 5 and 6, it is clear that the water contact angle was very small as less than 5 °, and the hydrophilization treatment was performed more effectively.

On the other hand, the comparative example 1 product hydrophilized by atmospheric pressure plasma using a mixed gas composed of Ar / He / CO ₂ / CH ₄ without using F ₂ gas has a water contact angle of 43.0 °. It was inferior to the hydrophilization treatment as compared with the example product. Similarly, Comparative Examples 3 and 4 which were hydrophilized by atmospheric pressure plasma using a mixed gas that did not use F ₂ gas had water contact angles of 47.0 ° and 44.0 °, respectively, so that they could be hydrophilized. It was inferior. Further, the comparative example 2 product hydrophilized by atmospheric pressure plasma using a mixed gas containing NF ₃ which is a fluorine-based gas has a water contact angle as large as 41.7 °, which is more hydrophilic than the example product. It was inferior to the chemical treatment.

  A polarizing plate was produced by a conventionally known method using the polymer film as the product of Example 1 thus obtained as a protective film. That is, first, two protective films were prepared, and an adhesive layer having a thickness of 0.1 μm was formed on each side using a PVA adhesive. On the other hand, a primer layer forming material prepared by dissolving methyl methacrylate resin in a mixed solvent of methyl ethyl ketone and cyclohexanone is prepared, and one of the two protective films is on the surface opposite to the adhesive layer forming surface. A primer layer was formed using the primer layer forming material. Furthermore, a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate is dissolved in a mixed solvent of methyl ethyl ketone and cyclohexanone, and a photopolymerization initiator (Irgacure 907, manufactured by Ciba Geigy) is added to prepare a hard coat layer forming material. did. Then, a hard coat layer was formed on the primer layer forming surface using the hard coat layer forming material. And the polarizing plate (refer FIG. 2) was obtained by adhere | attaching and laminating | stacking the said protective film with an adhesive layer on both surfaces of a polarizing film through an adhesive layer. The polarizing plate thus obtained had high reliability because the protective film was satisfactorily bonded through the adhesive layer. Furthermore, as a result of producing a polarizing plate in the same manner as described above using the polymer film of Examples 2 to 10 as a protective film, the protective film is well adhered as in the case of Example 1 A highly reliable one was obtained.

It is explanatory drawing which shows typically one Embodiment of the hydrophilization treatment method of the polymer film surface of this invention. It is sectional drawing which shows typically the structure of the polarizing plate comprised using the polymer film obtained by the hydrophilic treatment method of the polymer film surface of this invention as a protective film.

1 High voltage electrode 2 Low voltage electrode G Polymer film

Claims (8)

A polymer film is disposed in an atmospheric pressure plasma generator that disposes an object to be processed between opposing electrodes and performs treatment with atmospheric pressure plasma, and the polymer film is generated by the atmospheric pressure plasma generated in the apparatus. A method of hydrophilizing the surface, wherein the polymer film is a triacetyl cellulose film, and the F ₂ gas concentration is in the range of 0.1 to 2.0% by volume of the whole atmosphere gas. in have line treatment with atmospheric pressure plasma, hydrophilic treatment method of a polymer film surface water contact angle of the surface is characterized by obtaining a polymer film is 25 ° or less. The atmospheric gas is composed of He and _{F 2,} He / _{F 2} polymer film of claim 1 wherein (volume percent) = 98/2 to 99.9 / 0.1 mixture gas is set in a range of Surface hydrophilization treatment method. The method for hydrophilizing a polymer film surface according to claim 1 or 2 , wherein the time for generating the atmospheric pressure plasma is 3 to 180 seconds .   The said polymer film is a protective film for polarizing plates, The hydrophilic treatment method of the polymer film surface as described in any one of Claims 1-3.   The polymer film by which a film surface is hydrophilized by the hydrophilic treatment method of the polymer film surface as described in any one of Claims 1-4.   The polymer film according to claim 5, wherein a water contact angle on the surface of the polymer film subjected to hydrophilic treatment is 25 ° or less.   The polymer film according to claim 5 or 6, wherein the polymer film is a protective film for a polarizing plate.   It is a polarizing plate by which a protective film is laminated | stacked through the adhesive bond layer on both surfaces of a polarizing film, Comprising: The said protective film is a polymer film as described in any one of Claims 5-7 characterized by the above-mentioned. A polarizing plate.

Images