JP2007245454A - Manufacturing method of laminated film and optical film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a laminated film, which is enhanced in the adhesion between a transparent base material film and a functional layer or between functional layer and another functional layer laminated on the functional layer in a case that the continuously running long and wide transparent base material film is used as a support, using more simplified equipment. <P>SOLUTION: In the laminated film wherein the transparent base material film is used as the support, the functional layer is provided on the surface of the support and at least one kind of another functional layer different in composition from the functional layer is applied or laminated to the functional layer, plasma treatment and ultraviolet treatment are successively applied to the surface of the functional layer to be laminated under atmospheric pressure. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a laminated film that improves adhesion between a transparent substrate film and a functional layer, or between a functional layer and another functional layer having a different composition.

  In the production of a so-called optical film produced by using a transparent substrate film as a support and providing a functional layer on the surface, or further laminating another functional layer on the surface of the functional layer, the support When a functional layer is provided on the substrate, or when another functional layer is laminated on the functional layer, if the compositions differ greatly, it is often impossible to obtain sufficient adhesion.

  For example, the surface of various displays typified by liquid crystal displays is provided with a hard coat layer having a scratch resistance function on a transparent substrate film, in order to prevent contrast degradation and image reflection due to reflection of external light. The antireflection layer is laminated on the hard coat layer. In this case, when the composition differs greatly between the hard coat layer and the antireflection layer, sufficient adhesion cannot be obtained.

  In the case of a polarizing plate in which a protective film for polarizing plate is bonded with a polyvinyl alcohol film in which iodine or a dye is adsorbed and oriented, improvement in adhesion between the protective film and the polyvinyl alcohol film becomes a problem.

  For this reason, it has been conventionally attempted to improve the adhesion by soaking the surface to be laminated or intimately in a strong alkaline solution and saponifying the surface. For example, as in Patent Document 1, it is known that saponification of cellulose triacetate is effective for improving adhesion when laminating an optically anisotropic layer on cellulose triacetate. .

  Further, as a technique for improving the adhesion, there is a corona-treated surface or UV ozone treatment. For example, as in Patent Document 2, it is known to perform corona treatment or UV ozone treatment in order to improve the adhesion between the polarizer protective film and the polarizer film.

  Further, as in Patent Document 3, a surface modification method characterized by subjecting a fluororesin surface to a low-temperature plasma treatment and then subjecting it to excimer laser light or ArF excimer laser light irradiation treatment is known.

JP-A-8-94838 JP 2002-328224 A Japanese Patent Laid-Open No. 6-220228

  However, with regard to the alkali treatment, there are safety problems due to the environmental load such as waste liquid and the use of a high concentration alkaline solution. Moreover, since an independent large-sized installation is needed, there exists a fault that a process becomes complicated.

  In addition, surface treatment by UV ozone treatment or corona treatment has relatively few problems such as alkali treatment, such as environmental and safety problems and complicated processes. However, with respect to UV ozone treatment, the treatment time is slow, and with respect to corona treatment, high-speed running treatment is possible, but there is a drawback that the effect is weak.

  In addition, when excimer laser light or ArF excimer laser light irradiation treatment is performed under reduced pressure after low-temperature plasma treatment, a large apparatus is required because low-temperature plasma treatment is performed in a vacuum atmosphere. Uniform processing is difficult. Both are unsuitable for uniformly processing a long and wide film that runs continuously.

  Therefore, the present invention has an object to improve the adhesion between a long and wide transparent substrate film that runs continuously and a functional layer, or between the functional layer and another functional layer laminated on the functional layer. It was.

  The present invention has been made in view of the above problems, and improves adhesion between a long and wide transparent substrate film that travels and a functional layer, or another functional layer having a composition different from that of the functional layer. Therefore, it is an object to perform uniform surface modification at a high speed with a simplified equipment and continuously.

The invention according to claim 1 is a method for producing a laminated film in which a transparent substrate film is used as a support, and a functional layer is provided on the support surface.
A method for producing a laminated film comprising applying a functional layer to a surface of the support after applying a plasma treatment to the surface of the support under an atmospheric pressure and then an ultraviolet treatment under an atmospheric pressure. .

The invention according to claim 2 uses a transparent base film as a support, the functional layer 2 is provided on the surface of the support, and one or two other functional layers 3 having different compositions are provided on the surface of the functional layer 2. In the manufacturing method of the laminated film laminated above,
After subjecting the surface of the functional layer 2 to plasma treatment under atmospheric pressure and then ultraviolet treatment under atmospheric pressure, another functional layer 3 having a different composition is applied to the surface of the functional layer 2 by coating or bonding. Or it is a manufacturing method of the laminated | multilayer film characterized by laminating | stacking 2 or more types.

  The invention according to claim 3 is the method for producing a laminated film according to claim 1 or 2, wherein, in the plasma treatment, the energy of the active species generated by the plasma discharge is larger than the irradiation energy of ultraviolet rays.

  Invention of Claim 4 is a manufacturing method of the laminated | multilayer film in any one of Claims 1-3 which performs glow discharge and corona discharge as said plasma processing under the atmospheric pressure.

  The invention according to claim 5 is characterized in that, in the plasma treatment under atmospheric pressure, oxygen, air, ozone, carbon dioxide, carbon monoxide, water vapor, one or more of nitrogen or an inert gas, One type or two or more types of hydrogen peroxide are added, It is a manufacturing method of the laminated film in any one of Claims 1-4 characterized by the above-mentioned.

  The invention according to claim 6 is the method for producing a laminated film according to any one of claims 1 to 5, wherein an excimer ultraviolet ray having a wavelength of 172 nm is irradiated as the ultraviolet ray treatment under the atmospheric pressure.

  The invention according to claim 7 is one or two or more of nitrogen, inert gas, oxygen, ozone, carbon dioxide, carbon monoxide, water vapor, and hydrogen peroxide in the ultraviolet treatment under atmospheric pressure. It is a manufacturing method of the laminated | multilayer film in any one of Claims 1-6 characterized by the above-mentioned.

  Invention of Claim 8 is the optical film manufactured by the manufacturing method of the laminated | multilayer film in any one of Claims 1-7.

  By using the method of the present invention, the adhesion between a long and wide transparent substrate film that travels and the functional layer, or the functional layer and another functional layer having a different composition, can be further simplified. Moreover, the effect of improving by performing uniform surface modification at a high speed continuously is exhibited.

  Surface treatment is performed in the following order in order to improve the adhesion between the long and wide transparent base film that travels and the functional layer, or between the functional layer and another functional layer laminated on the functional layer. It is good to do.

  First, plasma treatment such as glow discharge or corona discharge is preferably performed. The active species such as radicals, ions, and electrons generated by glow discharge or corona discharge can cut the main chain bond on the treated surface along with the cleaning effect on the treated surface, thereby forming irregularities on the surface. It is.

  In order to further improve the adhesion, it is desirable to add one or more of oxygen, ozone, carbon dioxide, carbon monoxide, water vapor, and hydrogen peroxide to the plasma gas. Thereby, at the same time as the bond is broken, the oxygen content on the treated surface is increased, and more hydrophilic groups such as hydroxyl groups, carbonyl groups, and carboxyl groups can be introduced.

  Second, it is better to perform ultraviolet treatment. By irradiating with ultraviolet rays, ozone is generated from oxygen in the atmosphere, and oxygen radicals separated from the ozone are introduced into the main chain of the treatment surface. Here, plasma treatment or corona treatment is performed before ultraviolet treatment, and the treatment surface is cleaned and the bond of the main chain of the treatment surface is broken, so that the oxygen content of the treatment surface can be increased efficiently. Become.

  Regarding the order of the treatment, it is preferable to firstly perform a plasma treatment which is a high-energy treatment, and secondly, an ultraviolet treatment which can introduce oxygen into surface molecules with high efficiency. On the other hand, if the ultraviolet treatment is first and the plasma treatment is second, sufficient adhesion may not be obtained. Here, it is preferable that the energy of the active species generated by the plasma discharge is larger than the irradiation energy of ultraviolet rays. This has the effect of increasing the surface modification speed.

  In order to introduce oxygen atoms into the treatment surface more efficiently, excimer ultraviolet light may be used. The wavelength of the excimer ultraviolet light is 172 nm, and oxygen radicals are efficiently generated from oxygen, so that the oxygen content on the treated surface can be increased efficiently.

  In order to generate oxygen radicals more efficiently, one or more gases among nitrogen, inert gas, oxygen, ozone, carbon dioxide, carbon monoxide, water vapor, and hydrogen peroxide may be added. An atmosphere containing nitrogen that absorbs less ultraviolet light and oxygen that has a high reforming effect is preferable.

  Since the plasma treatment and the ultraviolet treatment are performed under atmospheric pressure, a decompression device is unnecessary, which can contribute to simplification of equipment. Moreover, since continuous processing is possible, it is suitable for processing a long and wide film.

FIG. 1 shows an example of an optical film.
Examples of the transparent substrate film 1 include cellulose films such as acetyl cellulose and triacetyl cellulose, polyester films such as polyethylene terephthalate and polyethylene naphthalate, and acrylic films such as polymethyl methacrylate, but are not limited thereto. It is not a thing.

  The functional layer to be laminated (including the functional layer 2 or 3) has, for example, functions such as high hardness, antireflection, anti-glare, and polarization, and the composition thereof is polyester, acrylic, urethane, amide. System, polyvinyl alcohol system, epoxy system, silicone system and the like, but are not limited thereto. The functional layer may contain fine particles such as silica and titanium dioxide, dichroic substances such as iodine and dichroic dyes, and those to which a fluorine-based material is added.

Here, as a method of laminating a functional layer on the surface of the transparent substrate film, a method by coating or bonding may be mentioned. Similarly, as a method of providing the functional layer 2 on the surface of the transparent substrate film and further laminating another functional layer 3 having a different composition on the surface of the functional layer 2, a method by coating or bonding may be mentioned.
Examples of the coating method include curtain coating, gravure coating, slot coating, and rod coating, but are not limited thereto. In addition, an adhesive or the like may be used for bonding.

  The optical film 4 is a film that exhibits functions such as high hardness, antireflection, antiglare, and polarization by laminating one or more functional layers on the transparent base film 1.

  By using triacetyl cellulose with a thickness of 80 μm for the transparent substrate film, applying a coating solution for hard coat whose main component is an ultraviolet curable acrylic resin, drying at 70 ° C. for 1 minute, and then curing with ultraviolet rays, A hard coat layer was formed.

  The surface of the hard coat layer formed on the film was first subjected to plasma treatment by glow discharge, and then irradiated with excimer ultraviolet rays.

  After applying the above-mentioned treatment, a low-refractive index coating solution containing tetraethoxysilane as a main component and 1.0N-HCl as a catalyst is applied to the surface of the hard coat layer and dried at 120 ° C. for 5 minutes. Formed.

  For the plasma treatment by glow discharge, ADMASTER-350b (manufactured by E-Square Co., Ltd.) was used, and plasma gas (nitrogen and clean dry air, ratio 4000: 3) was allowed to flow under atmospheric pressure. Moreover, the conveyance speed of the film was 1.5 m / min.

  Excimer ultraviolet treatment used UEEX503 (made by Iwasaki Electric Co., Ltd.), and set the distance between the lamp irradiation surface and the film to 3 mm in the atmosphere. Moreover, the conveyance speed of the film was 1.5 m / min.

<Comparative Example 1>
Except that the surface of the hard coat layer formed on the film was first irradiated with excimer ultraviolet light and then subjected to plasma treatment by glow discharge, the same as in Example 1.

<Comparative example 2>
The same as Example 1 except that the surface of the hard coat layer formed on the film was only subjected to plasma treatment by glow discharge.

<Comparative Example 3>
The same as Example 1 except that the surface of the hard coat layer formed on the film was only irradiated with excimer ultraviolet rays.

<Comparative example 4>
Example 1 is the same as Example 1 except that the surface of the hard coat layer formed on the film is subjected to alkali treatment.

  In the alkali treatment, the film was immersed in a 1.5N NaOH solution at 40 ° C. for 5 minutes, then washed with water and dried.

  In the optical films produced in Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 3 and Comparative Example 4, the physical properties of the hard coat layer surface and the evaluation of the adhesion between the hard coat layer and the antireflection layer are as follows. The method of was used.

  The surface of the hard coat layer subjected to the above treatment was measured for water droplet contact angle with a contact angle meter (manufactured by Kyowa Interface Science Co., Ltd.) to evaluate the hydrophilicity of the hard coat surface.

  Regarding adhesion, steel wool (# 0000) was rubbed 10 reciprocally at a load of 250 g, and the scratching was visually evaluated. The method of scratching was evaluated according to the following four levels. ：: Scratches cannot be confirmed, ○: Several scratches can be confirmed, △: Dozens of scratches can be confirmed, ×: Many scratches can be confirmed.

  From the above results, the surface to be laminated with the functional layer is first subjected to plasma treatment under atmospheric pressure and secondly excimer ultraviolet treatment, so that adhesion to other functional layers to be laminated on the functional layer is improved. I found it to improve. In addition, because it can achieve the same level of adhesion as alkali treatment, it can solve the environmental load and safety problems associated with alkali treatment, and it can perform uniform surface modification with more simplified equipment. It becomes possible.

It is an example of an optical film.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent base film 2 Functional layer 3 Functional layer whose composition is different from 2 4 Optical film

Claims (8)

In the method for producing a laminated film in which a transparent base film is used as a support and a functional layer is provided on the support surface
A method for producing a laminated film, wherein the support surface is subjected to plasma treatment under atmospheric pressure and then subjected to ultraviolet treatment under atmospheric pressure, and then a functional layer is applied or bonded to the surface of the support. A method for producing a laminated film in which a transparent base film is used as a support, the functional layer 2 is provided on the surface of the support, and one or more other functional layers 3 having different compositions are laminated on the surface of the functional layer 2 In
After subjecting the surface of the functional layer 2 to plasma treatment under atmospheric pressure and then ultraviolet treatment under atmospheric pressure, another functional layer 3 having a different composition is applied to the surface of the functional layer 2 by coating or bonding. Or the manufacturing method of the laminated | multilayer film characterized by laminating | stacking 2 or more types.   The method for producing a laminated film according to claim 1 or 2, wherein in the plasma treatment, the energy of active species generated by plasma discharge is greater than the irradiation energy of ultraviolet rays.   The method for producing a laminated film according to claim 1, wherein glow discharge or corona discharge is performed as the plasma treatment under atmospheric pressure.   In the plasma treatment under atmospheric pressure, one or more of oxygen, air, ozone, carbon dioxide, carbon monoxide, water vapor, and hydrogen peroxide may be added to one or more of nitrogen or an inert gas. 2 or more types are added, The manufacturing method of the laminated | multilayer film in any one of Claims 1-4 characterized by the above-mentioned.   The method for producing a laminated film according to claim 1, wherein excimer ultraviolet light having a wavelength of 172 nm is irradiated as the ultraviolet treatment under atmospheric pressure.   In the ultraviolet treatment under the atmospheric pressure, one or more kinds of gases among nitrogen, inert gas, oxygen, ozone, carbon dioxide, carbon monoxide, water vapor, and hydrogen peroxide are added. The manufacturing method of the laminated | multilayer film in any one of Claims 1-6.   The optical film manufactured by the manufacturing method of the laminated | multilayer film in any one of Claims 1-7.

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