JP2014205126A - Gravure roll and production method of laminated film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gravure roll capable of reducing thickness fluctuation of a coating layer when coating widely, and suppressing generation of a streaky defect, and to provide a production method of a laminated film using the gravure roll.SOLUTION: In a gravure roll, a cell is formed on the peripheral surface of a cylindrical base material roll. In the gravure roll, the outer diameter of the gravure roll is 150 mm or less, the length of the gravure roll is 1,100 mm or longer, and the material of the base material roll is ceramic.

Description

  The present invention relates to a gravure roll and a method for producing a laminated film using the gravure roll. Specifically, in the production of a laminated film in which a coating layer is laminated on a base film using a gravure roll, a gravure roll and a laminated film that can suppress fluctuations in the coating layer thickness in the coating width direction and occurrence of streak-like defects It relates to the manufacturing method.

  A coating method using a gravure roll is generally known, and is particularly suitable for coating a thin film. The gravure roll is a roll in which cells are formed on the peripheral surface of the roll. After the coating liquid supplied to the gravure roll is once held in the cell, the gravure roll comes into contact with the substrate film to be continuously conveyed, thereby bringing the gravure roll into contact with the substrate film. A coating solution is applied onto the substrate film.

  As the gravure roll, a gravure roll in which cells are formed by engraving or the like on a peripheral surface of a metal base material roll made of carbon steel or stainless steel is generally known.

  Also known is a gravure roll in which a cell forming layer made of ceramic is provided on the peripheral surface of a metal base material roll made of carbon steel or stainless steel, and a cell is formed on the cell forming layer by a laser or the like (patent) References 1, 2). In patent document 1 and patent document 2, what provided the cell formation layer which consists of ceramics in the surrounding surface of such a metal base material roll is called the ceramic gravure roll. However, the ceramic gravure rolls disclosed in Patent Document 1 and Patent Document 2 do not use a base material roll made of ceramic.

  On the other hand, an optical film having functions such as an antireflection function, an antiglare function, a hard coat function, a conductive function, an antistatic function, and a color correction function is used for an image display surface and a display device (touch panel). ) Is used inside.

  Various functional layers constituting these optical films (for example, an antireflection layer, an antiglare layer, a hard coat layer, a conductive layer, an antistatic layer, a color correction layer, etc.) have high film thickness accuracy (thickness Small variation) is required. When the variation in the thickness of these functional layers (thickness variation) becomes large, there may be inconveniences such as interference fringes and color unevenness becoming conspicuous.

  Furthermore, these optical films are required to have few defects such as stripes and unevenness.

JP 2001-104852 A JP 2003-260393 A

  The coating method using a gravure roll is suitable for thin film coating as described above, and a gravure roll having a relatively small outer diameter (for example, an outer diameter of 150 mm or less) is particularly suitable for thin film coating.

  Further, in the production of a laminated film in which a coating layer having various functions is laminated (coated) on a base film, it is effective to increase the coating width in order to increase productivity.

  However, in a coating method using a gravure roll having a relatively small outer diameter, when the coating width is increased in order to increase productivity (for example, when the coating width is 1100 mm or more), the thickness variation of the coating layer in the coating width direction ( There is a problem that (variation) becomes large.

  Moreover, since the gravure roll coating method is a coating method in which the coating layer is applied while the base film and the gravure roll are in contact with each other, there is a problem that streak-like defects are likely to occur. It has been found that this streak-like defect is likely to occur when coating is performed with a wide width (for example, an application width of 1100 mm or more) using a gravure roll having a relatively small outer diameter (for example, an outer diameter of 150 mm or less).

  Accordingly, an object of the present invention is to reduce the variation in the thickness of the coating layer when applying with a gravure roll having a relatively small outer diameter to increase the coating width, and to suppress the occurrence of streak-like defects. It is in providing the gravure roll which can be manufactured, and the manufacturing method of the laminated film using this gravure roll.

The above object of the present invention has been basically achieved by the following invention.
[1] A gravure roll in which cells are formed on the peripheral surface of a cylindrical base material roll, the outer diameter of the gravure roll being 150 mm or less, the length of the gravure roll being 1100 mm or more, and the material of the base material roll A gravure roll, characterized in that is a ceramic.
[2] The gravure roll according to 1 above, wherein the outermost surface of the peripheral surface of the gravure roll is coated with diamond-like carbon.
[3] In the method for producing a laminated film in which a coating layer is laminated on a base film using a gravure roll, the gravure roll is a gravure roll in which cells are formed on the peripheral surface of a cylindrical base material roll. A method for producing a laminated film, wherein an outer diameter of the gravure roll is 150 mm or less, a length of the gravure roll is 1100 mm or more, and a material of the base material roll is ceramic.
[4] The method for producing a laminated film as described in 3 above, wherein the outermost surface of the peripheral surface of the gravure roll is coated with diamond-like carbon.
[5] The method for producing a laminated film as described in 3 or 4 above, wherein the coating width is 1100 mm or more.

  According to the present invention, it is possible to suppress the problems associated with the widening of the coating width, that is, the variation in thickness (variation) of the coating layer in the coating width direction and the occurrence of streak-like defects. The gravure roll of the present invention and the method for producing a laminated film using the gravure roll are particularly suitable for an optical film production method that requires high thickness accuracy of the coating layer and low occurrence of streak-like defects. is there.

FIG. 1 is a side view of a gravure roll of the present invention. FIG. 2 is a perspective view of a base material roll constituting the gravure roll of the present invention. FIG. 3 is a partial schematic cross-sectional view of the gravure roll of the present invention. In order to explain the range of the bank portion in FIG. 3, the bank portion is indicated by a solid line, and the cell is indicated by a dotted line. FIG. 4 is a schematic view showing an example of a reverse gravure coating apparatus used in the present invention. FIG. 5 is a schematic view for explaining the contact angle between the base film and the gravure roll.

[Gravure roll]
The gravure roll of the present invention is a gravure roll in which cells are formed on the peripheral surface of a cylindrical base material roll made of ceramic. The outer diameter of the gravure roll is 150 mm or less and the length is 1100 mm or more.

  FIG. 1 is a side view (schematic diagram) of a gravure roll of the present invention. The outer diameter (maximum diameter) of the gravure roll 10 is a dimension indicated by a symbol D, and the length (surface length) of the gravure roll is a dimension indicated by a symbol L.

  The gravure roll of the present invention has an outer diameter (D) of 150 mm or less and a length (L) of 1100 mm or more. That is, the gravure roll of the present invention is a gravure roll having a relatively small outer diameter and a relatively long length. Such a gravure roll generally has a large amount of deflection due to its own weight. When the amount of bending of the gravure roll increases, the thickness variation (variation) of the coating layer in the coating width direction tends to increase, and stripe-like defects tend to occur. The amount of flexure of the gravure roll is the dimension indicated by the symbol V in FIG.

  In the present invention, the base material roll of the gravure roll is made of ceramic and cylindrical, so that even if the outer diameter of the gravure roll is 150 mm or less and the length is 1100 mm or more, the amount of flexure of the gravure roll is small. As a result, it has been found that the thickness variation (variation) of the coating layer in the coating width direction is reduced and the occurrence of streak-like defects is suppressed.

  In thin film coating using a gravure roll, it is important to stably form a bead of a coating liquid sandwiched between the base film and the gravure roll. For this purpose, the contact area between the base film and the gravure roll is to be reduced. It is effective to make it smaller. In order to reduce the contact area between the base film and the gravure roll, it is effective to reduce the outer diameter of the gravure roll.

  That is, the outer diameter of the gravure roll is preferably 150 mm or less in order to realize a stable and uniform thin film coating. From this viewpoint, the outer diameter of the gravure roll is preferably 120 mm or less, more preferably 100 mm or less, and particularly preferably 90 mm or less. The lower limit of the outer diameter of the gravure roll is preferably more than 20 mm, more preferably more than 30 mm, and particularly preferably more than 50 mm from the viewpoint of reducing the amount of bending of the gravure roll.

  The length of the gravure roll is preferably as large as possible from the viewpoint of increasing productivity by increasing the coating width. Specifically, 1300 mm or more is preferable, 1500 mm or more is more preferable, and 1600 mm or more is preferable. The upper limit of the length of the gravure roll is preferably 3000 mm or less, more preferably 2500 mm or less, and particularly preferably 2300 mm or less from the viewpoint of keeping the amount of bending of the gravure roll small.

  In the gravure roll of the present invention, cells are formed on the peripheral surface of a cylindrical base material roll made of ceramic.

  FIG. 2 is a perspective view of a base material roll constituting the gravure roll of the present invention. The gravure roll of the present invention has a cell (not shown) formed on the peripheral surface of the base material roll 1. The base material roll 1 is a cylindrical hollow roll made of ceramic. By making the base material roll into a cylindrical roll, the amount of bending of the gravure roll is reduced.

  The ratio (di / do) of the outer diameter (do) [mm] and the inner diameter (di) [mm] of the base material roll 1 is 0.50 to 0.90 from the viewpoint of reducing the amount of bending of the gravure roll. The range is preferable, the range of 0.55 to 0.85 is more preferable, and the range of 0.60 to 0.80 is particularly preferable.

  The thickness (t) of the base material roll 1 is preferably in the range of 3 to 25 mm, more preferably in the range of 5 to 20 mm, and particularly preferably in the range of 7 to 15 mm from the viewpoint of workability of the base material roll.

  In the gravure roll of the present invention, cells are formed on the peripheral surface of the base material roll, but the cells may be formed directly on the base material roll, or the cell forming layer is provided on the peripheral surface of the base material roll. And a cell may be formed in the cell formation layer. In the gravure roll of the present invention, it is preferable to provide the latter cell forming layer and form cells in the cell forming layer.

  FIG. 3 is a partial schematic cross-sectional view of an example of the gravure roll of the present invention. A cell forming layer 2 is provided on the peripheral surface of the base material roll 1, and cells 3 are formed on the cell forming layer 2. The cell 3 is partitioned by the bank portion 4. Here, if the range of the bank part 4 is demonstrated using FIG. 3A, the part shown as the continuous line in FIG. 3A is a bank part.

  The depth of the cell 3 is suitably in the range of 5 to 100 μm, and preferably in the range of 10 to 50 μm. The thickness of the cell forming layer 2 for forming such a cell is preferably in the range of 10 to 500 μm, more preferably in the range of 20 to 300 μm, and particularly preferably in the range of 30 to 150 μm.

  The shape of the cell formed on the peripheral surface of the gravure roll is not particularly limited, and for example, a generally known oblique line type, lattice type (rectangular shape), honeycomb type (tortoise shell type), pyramid type, etc. are adopted. be able to. Among the above cells, a hatched cell is particularly preferable.

  The gravure roll of the oblique line type cell is a gravure roll generally formed in a gravure coating method, in which a cell having a spiral oblique line groove is formed on the peripheral surface of the roll.

  The number of hatched cells is preferably in the range of 30 to 300 lines per inch (25.4 mm), more preferably in the range of 50 to 250 lines, and particularly preferably in the range of 80 to 200 lines. The depth of the cell is preferably in the range of 20 to 300 μm, more preferably in the range of 30 to 200 μm, and particularly preferably in the range of 40 to 100 μm. Further, the inclination angle of the oblique cell (angle relative to the rotation axis direction of the gravure roll) is generally in the range of 30 to 70 degrees, and preferably in the range of 40 to 60 degrees.

  The cell forming layer is preferably formed by spraying ceramic on the peripheral surface of the base material roll. For example, plasma spraying may be used for ceramic spraying. As a method of forming cells in such a cell formation layer, a laser ablation method can be given.

  A known ceramic can be used as the ceramic constituting the base material roll. For example, ceramics such as alumina, silicon nitride, aluminum nitride, silicon carbide, zirconia, titania, cermet, and sapphire can be used.

  Ceramics have a higher Young's modulus and lower specific gravity than metals such as carbon steel and stainless steel, so gravure rolls using a base metal roll made of ceramic are gravure using a conventional metal base roll. Compared with a roll, the amount of bending of a gravure roll can be reduced.

  Therefore, in the gravure roll having an outer diameter (D) of 150 mm or less and a length (L) of 1100 mm or more, the base material roll is made of ceramic, thereby reducing the bending amount of the gravure roll. Becomes larger.

  From the viewpoint of reducing the bending amount of the gravure roll, a ceramic having a high Young's modulus is preferable as the ceramic constituting the base material roll. For example, a ceramic having a Young's modulus of 250 GPa or more is preferable, and a ceramic having a Young's modulus of 300 GPa or more is more preferable. Examples of such a high Young's modulus ceramic include alumina, silicon nitride, aluminum nitride, silicon carbide, cermet, and sapphire. Among these, alumina is particularly preferably used.

  As the ceramic constituting the cell forming layer, a known ceramic can be used. For example, ceramics such as chromium oxide, alumina, silicon nitride, aluminum nitride, zirconia, and titania are preferably used.

  The amount of bending in the length direction of the gravure roll (V: maximum amount of bending due to its own weight) is preferably 0.1 mm or less, more preferably 0.08 mm or less, and particularly preferably 0.06 mm or less. For example, when the inner diameter (di) of the base material roll is 45 mm, the outer diameter (D) of the gravure roll is 60 mm, and the length (L) of the gravure roll is 1800 mm, the bending of the gravure roll made of stainless steel is the base material roll material. The amount is 0.14 to 0.16 mm, but the bending amount of the gravure roll whose base material roll is ceramic (alumina) is 0.04 to 0.05 mm.

  The amount of bending (V) of the gravure roll is set, for example, by horizontally installing the shaft portions 11 at both ends of the gravure roll 10 on an installation table (not shown), and the amount of bending (maximum amount of bending) V due to the gravure roll 10's own weight is, for example, It can be measured with a laser displacement meter.

  In the gravure roll of the present invention, the outermost surface of the roll peripheral surface is preferably coated with diamond-like carbon (hereinafter referred to as “DLC”). This further suppresses the thickness variation of the coating layer in the coating width direction and the occurrence of streak-like defects. Here, the outermost surface of the peripheral surface of the gravure roll being covered with DLC means that at least the bank portion 4 of the gravure roll 1 is covered in FIGS. 3 and 3A.

  The application method using the gravure roll is a method in which the peripheral surface of the gravure roll is applied (contacted) against the base film, and the bank portion which is a contact portion with the base film in the gravure roll is a DLC coating. It is preferable to coat with.

  In the present invention, only the bank portion may be covered with the DLC coating, or both the bank portion and the inside of the cell may be covered with the DLC coating. From the viewpoint of improving the wear resistance of the gravure roll, it is preferable that both the bank portion and the inside of the cell are covered with the DLC film. That is, it is preferable that the entire exposed portion of the peripheral surface of the gravure roll is covered with the DLC film.

  The DLC film can be coated on the peripheral surface of the gravure roll by sputtering or plasma CVD. By covering the roll peripheral surface with the DLC film by sputtering or plasma CVD, the bank portion of the roll peripheral surface and the inside of the cell are usually coated together with the DLC film.

  The thickness of the DLC film is preferably 0.1 μm or more, more preferably 0.5 μm or more, and particularly preferably 1 μm or more. The upper limit thickness is preferably 15 μm or less, more preferably 10 μm or less, and particularly preferably 5 μm or less.

[Manufacturing method of laminated film using gravure roll]
The manufacturing method of the laminated film which laminates | stacks an application layer on a base film using a gravure roll is demonstrated below.

  As a coating method using a gravure roll, it is preferable to adopt a reverse gravure coating method. In such a reverse gravure coating method, a gravure roll that is rotated in a direction opposite to the transport direction of a continuously transported base film is pressed against the base film, thereby being supplied to the gravure roll (which constitutes a coating layer). ) A coating method in which a coating solution is applied to a substrate film. Usually, before the coating liquid supplied to the gravure roll is applied to the base film, the excess is scraped off by a doctor blade to adjust the coating amount.

  The reverse gravure coating method will be described below. FIG. 4 is a schematic diagram illustrating an example of a reverse gravure coating apparatus. This reverse gravure coating apparatus is a kiss system, and includes a gravure roll 10, a coating liquid supply means 20, a doctor blade 30, and a pair of transport rollers 41 and 42. Here, the kiss method is a method in which a back roll is not disposed at a position facing the gravure roll 10 with the substrate film 50 interposed therebetween, and the substrate is conveyed while being supported by a pair of conveying rollers 41 and 42. In this method, the gravure roll 10 is pressed against the film 50 and applied.

  The gravure roll 10 is driven and rotated in the direction of arrow y by a rotation driving means (not shown). The coating liquid supply means 20 includes a coating liquid storage container 21 and a coating liquid 22 accommodated in the coating liquid storage container 21. The pair of transport rollers 41 and 42 are arranged at predetermined intervals on both sides of the gravure roll 10, and the base film 50 is transported in the direction of arrow z with the gravure roll 10 being pressed.

  The gravure roll 10 is arranged so that the lower part thereof is immersed in the coating liquid 22 in the coating liquid storage container 21. By rotating the gravure roll 10, the coating liquid is supplied to the cells formed on the peripheral surface of the gravure roll 10, and the surplus coating liquid on the peripheral surface of the gravure roll 10 is scraped off by the doctor blade 30, and the amount of the coating liquid is reduced. Adjusted. The gravure roll 10 is pressed against the base film 50 while rotating the gravure roll 10 in the direction opposite to the conveying direction of the base film 50 (direction of arrow z) (direction of arrow y). The coating solution in the cell is applied to the base film 50.

  The material of the doctor blade is not particularly limited, but a doctor base material made of stainless steel, carbon steel or the like in which the contact portion with the gravure roll is coated with a fluororesin is preferably used.

  In the present invention, a wider coating width is preferable from the viewpoint of improving productivity. Specifically, the coating width is preferably 1100 mm or more, more preferably 1300 mm or more, and particularly preferably 1500 mm or more. The upper application width is about 3000 mm.

  When the coating width is increased in this way, the thickness variation (variation) of the coating layer in the coating width direction is likely to increase, and streak-like defects are likely to occur, but the coating width is widened by using the gravure roll of the present invention. Even if it is a case, the fluctuation | variation of the coating layer thickness in a coating width direction and generation | occurrence | production of a stripe-shaped defect can be suppressed.

  The coating solution for forming the coating layer is preferably a coating solution having a relatively low viscosity. Specifically, the viscosity (23 ° C.) of the coating solution is preferably 50 mPa · s or less, more preferably 30 mPa · s or less, and particularly preferably 10 mPa · s or less. The lower limit viscosity of the coating solution is about 0.3 mPa · s.

  The dry thickness of the coating layer is suitably in the range of 0.01 to 10 μm, and preferably in the range of 0.02 to 5 μm. The dry thickness of the coating layer can be controlled by adjusting the solid content concentration of the coating liquid (composition) for forming the coating layer, and selecting and adjusting the shape and cell volume of the gravure roll cell.

  The present invention has a feature that even if the dry thickness of the coating layer is a thin film, variation in the thickness of the coating layer in the coating width direction and streak-like defects can be effectively suppressed. Therefore, the method for producing a laminated film using the gravure roll of the present invention is effective when the dry thickness of the coating layer is less than 3 μm, more effective when it is less than 1 μm, and particularly effective when it is less than 0.5 μm. And is most effective when the thickness is less than 0.2 μm.

  In the above reverse gravure coating method, it is preferable to reduce the contact angle (holding angle) between the gravure roll and the substrate film from the viewpoint of further suppressing the occurrence of streak-like defects.

  The contact angle (holding angle) between the gravure roll and the base film will be described with reference to FIG. The base film 50 transported in the direction of the arrow is first separated from the straight line connecting the first contact point of the gravure roll 10 and the center point of the gravure roll 10 and the base film 50 transported while contacting the gravure roll 10 for the first time. The angle θ formed by the contact and the straight line connecting the center point of the gravure roll 10 is the contact angle (holding angle) between the gravure roll and the base film.

  In the present invention, the contact angle (holding angle) θ between the gravure roll and the base film is preferably 5 degrees or less, more preferably 3 degrees or less, particularly preferably 2 degrees or less, and most preferably 1 degree or less. The lower limit of the contact angle (holding angle) is preferably 0.1 degree or more.

[Laminated film]
The method for producing a laminated film using the gravure roll of the present invention is suitable for the method for producing an optical film. The optical film is used inside an image display surface such as an image display device or a touch panel or a display device (touch panel). As an optical film, for example, an antireflection film, a hard coat film, a transparent conductive film, a laminated film before laminating a conductive layer of a transparent conductive film for an electrode of a touch panel (color adjustment or electrode pattern of the conductive layer described above) For example, a laminated film for preventing the appearance of bones (a pattern can be seen) can be used.

  These optical films are obtained by laminating coating layers having various functions on a base film. Details of the coating layer will be described later.

[Base film]
As the base film used in the present invention, polyester resin film, cellulose resin film, polyolefin resin film, acrylic resin film, polycarbonate resin film, cyclic olefin resin film, epoxy resin film, polyimide resin film, polyetherimide resin film, polyamide Examples thereof include a resin film, a polysulfone resin film, a polyphenylene sulfide resin film, and a polyether sulfone resin film. Among these resin films, polyester resin films are preferable, and among polyester resin films, polyethylene terephthalate films are preferable because of their excellent physical properties (strength, wear resistance, etc.) and solvent resistance.

  The thickness of the base film is suitably in the range of 10 to 300 μm, preferably in the range of 20 to 250 μm, particularly preferably in the range of 20 to 200 μm.

  The base film may be provided with an easy adhesion layer, a base layer, a primer layer, and the like in advance.

[Coating layer]
The composition and function of the coating layer are not particularly limited, and are appropriately selected according to the use of the laminated film. For example, when the laminated film is an antireflection film, the antireflection layer (high refractive index layer, medium refractive index layer, low refractive index, etc.) is the coating layer, and when the laminated film is a hard coat film, the hard coat layer is coated. Become a layer.

  Moreover, when a laminated film is a transparent conductive film, a conductive layer becomes a coating layer. As this conductive layer, conductive materials such as conductive fibers such as silver nanowires and carbon nanotubes, π-conjugated conductive polymers such as polythiophene and polyaniline, and cationic polymers such as quaternary ammonium salt polymers The thing containing is mentioned.

  Moreover, the transparent conductive film used for the electrode of the touch panel has a specific refractive index on the surface on which the conductive layer is laminated in order to adjust the color of the conductive layer and prevent bone appearance of the electrode pattern (the pattern can be seen). An intermediate layer or a hard coat layer may be provided. The laminated film obtained by the production method of the present invention is also suitable as a laminated film provided with an intermediate layer or a hard coat layer before the conductive layer of the transparent conductive film is laminated. In this case, the intermediate layer or the hard coat layer becomes the coating layer.

  Examples of the intermediate layer include a high refractive index layer having a refractive index of 1.60 to 1.80 and a low refractive index layer having a refractive index of 1.30 to 1.50. Examples of the hard coat layer include a general hard coat layer having a refractive index of 1.48 to 1.54 or a high refractive index hard coat layer having a refractive index of 1.55 to 1.80.

  In the present invention, the coating layer includes a hard coat layer, an antireflection layer, an antiglare layer, a conductive layer, an antistatic layer, a refractive index adjusting layer (the above-described high refractive index layer and low refractive index layer), a color tone adjusting layer and an antireflection layer. It is preferably any one functional layer selected from the group consisting of dirty layers.

  The coating layer is preferably a thermosetting resin layer or an active energy ray curable resin layer, and particularly preferably an active energy ray curable resin layer.

  The thermosetting resin layer is a resin that is polymerized or cross-linked by heat, such as acrylic resin, polyester resin, polyurethane resin, polycarbonate resin, polystyrene resin, polyolefin resin, fluorine resin, polyimide resin, etc. It is a layer that is cured by heating after applying a composition (coating liquid) containing a curable resin.

  The active energy ray-curable resin layer is applied with a composition (coating liquid) containing an active energy ray-curable resin that is polymerized and cured with active energy rays such as ultraviolet rays and electron beams, and then irradiated with active energy rays. It is a layer hardened by.

  As the active energy ray-curable resin, a monomer or oligomer having at least one ethylenically unsaturated group in the molecule is preferably used. Here, examples of the ethylenically unsaturated group include an acryloyl group, a methacryloyl group, a vinyl group, and an allyl group.

  Examples of monomers having at least one ethylenically unsaturated group in the molecule include methyl (meth) acrylate, lauryl (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, methoxytriethylene glycol (meth) acrylate, Phenoxyethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 2-hydroxy-3-phenoxy (meth) acrylate Monofunctional acrylates such as neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, Ritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, Multifunctional acrylates such as tripentaerythritol tri (meth) acrylate, tripentaerythritol hexa (meth) triacrylate, trimethylolpropane (meth) acrylic acid benzoate, trimethylolpropane benzoate, glycerin di (meth) acrylate hexa Urethane acrylates such as methylene diisocyanate, pentaerythritol tri (meth) acrylate hexamethylene diisocyanate Mention may be made of a door or the like.

  Examples of oligomers having at least one ethylenically unsaturated group in the molecule include polyester (meth) acrylate, polyurethane (meth) acrylate, epoxy (meth) acrylate, polyether (meth) acrylate, and alkit (meta ) Acrylate, melamine (meth) acrylate, silicone (meth) acrylate and the like.

  The above-mentioned monomers and oligomers having at least one ethylenically unsaturated group in the molecule may be used alone or in combination. It is preferable to use at least a trifunctional or higher polyfunctional monomer or polyfunctional oligomer.

  When the coating layer is a high refractive index layer or a high refractive index hard coat layer, the active energy ray curable composition (coating liquid) containing the above active energy ray curable resin further contains metal oxide particles. As such metal oxide particles, zirconium oxide and titanium oxide are preferably used.

  The content of the metal oxide particles in the active energy ray-curable composition is preferably 20% by mass or more, more preferably 30% by mass or more, based on 100% by mass of the total solid content of the active energy ray-curable composition. Mass% or more is particularly preferable, and 50 mass% or more is most preferable. The upper limit is preferably 95% by mass or less, more preferably 90% by mass or less, and particularly preferably 85% by mass or less.

  The active energy ray-curable composition preferably contains a photopolymerization initiator. Specific examples of such a photopolymerization initiator include acetophenone, 2,2-diethoxyacetophenone, p-dimethylacetophenone, p-dimethylaminopropiophenone, benzophenone, 2-chlorobenzophenone, 4,4′-dichloro. Benzophenone, 4,4′-bisdiethylaminobenzophenone, Michler's ketone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, methylbenzoyl formate, p-isopropyl-α-hydroxyisobutylphenone, α-hydroxyisobutylphenone, Carbonyl compounds such as 2,2-dimethoxy-2-phenylacetophenone and 1-hydroxycyclohexyl phenyl ketone, tetramethylthiuram monosulfide, Sulfur compounds such as tetramethylthiuram disulfide, thioxanthone, 2-chlorothioxanthone, and 2-methylthioxanthone can be used.

  Moreover, generally the photoinitiator is marketed and they can be used. For example, Irgacure 184, 907, Irgacure 379, Irgacure 819, Irgacure 127, Irgacure 500, Irgacure 754, Irgacure 250, Irgacure 1800, Irgacure 1870, Irgacure OXE01, DAROCURT, POROCURUR, manufactured by Ciba Specialty Chemicals Co., Ltd. SPEEDCURE MBB, SPEEDCURE PBZ, SPEEDCURE ITX, SPEEDCURE CTX, SPEEDCURE EDB, YK AC, Y K-AC, ACC RE DMBI etc. are mentioned.

  These photopolymerization initiators may be used alone or in combination of two or more.

  The content of the photopolymerization initiator is suitably in the range of 0.1 to 10% by mass, and in the range of 0.5 to 8% by mass with respect to 100% by mass of the total solid content of the active energy ray-curable composition. preferable.

  When the coating layer is a low refractive index layer, instead of the metal oxide particles in the active energy ray-curable composition forming the high refractive index layer, low refractive index particles such as silica and magnesium fluoride, or A fluorine compound is used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by these Examples. The measurement method, evaluation method, and materials used in this example are shown below.

[Measurement method and evaluation method]
(1) Measurement of coating layer thickness (dry thickness) The cross-section of the laminated film was cut into ultra-thin sections, and 50,000 times to 300,000 times at an accelerating voltage of 100 kV using a transmission electron microscope (H-7100FA type manufactured by Hitachi). The cross section of the laminated film was observed at a magnification, and the thickness of the coating layer was measured. In addition, the thickness was measured by dividing the coating width direction into five at regular intervals and averaging at each location.

(2) Measurement of refractive index of coating layer A coating film (dry thickness of about 2 μm) formed by applying a composition for forming a coating layer on a silicon wafer with a spin coater was measured under a temperature condition of 25 ° C. The refractive index of 589 nm was measured with a phase difference measuring device (Nikon Corporation: NPDM-1000).

(3) Measurement of coating layer thickness (dry thickness) variation in the coating width direction On the surface of the laminated film on which the coating layer is laminated, the optical film thickness is measured at intervals of 100 mm in the coating width direction. From the thickness, the thickness variation (%) of the coating layer in the coating width direction was determined by the following formula 1.

The coating length was 2000 m each, and the thickness variation of the coating layer was measured at two places, a coating start portion (portion where 100 m was applied) and a coating end portion (portion where 2000 m was applied).
{(Tmax−Tmin) / Ta} × 100 Equation 1
In Equation 1, Tmax represents the maximum thickness [μm], Tmin represents the minimum thickness [μm], and Ta represents the average thickness [μm].

<Measurement of optical film thickness>
The base film surface opposite to the surface on which the coating layer of the laminated film is laminated is uniformly scratched with a water resistant sandpaper of # 320 to 400, and then black oil-based ink (Magic Ink (registered trademark)) is applied. The reflection spectrum of the coating layer surface (450 to 600 nm) using a spectrophotometer UV-3150 manufactured by Shimadzu Corporation, with the coating completely removed from the surface opposite to the coating layer. Was measured, and the optical film thickness was obtained from the obtained reflection spectrum and the refractive index of the coating layer using dedicated software incorporated in the spectrophotometer UV-3150.

(4) Evaluation of streaky defects The surface on which the coating layer of the laminated film was laminated was irradiated with an LED lamp, and the streaky defects were visually observed. Three healthy men in their 20s were observed and examined for the number of streaky defects that could be visually recognized, and the number was averaged. Each observation area is 30 m ² . The evaluation criteria are shown below.
G1; the number of stripe-like defects is less than 0.5 / m ² G2; the number of stripe-like defects is 0.5 / m ² or more and less than 1.0 / m ² G3; the number of stripe-like defects is 1.0 / m ² or more 1.5 / ^{m 2} less than G4; striped defects number is 1.5 / ^{m 2} or more and 3.0 pieces / ^{m 2} less than G5; striped defects number is 3.0 pieces / ^{m 2} or more 5 less than .0 pieces / ^{m 2} G6; striped defects number is 5.0 pieces / ^{m 2} or more.

[Gravure roll]
<Gravure roll a>
A ceramic (chromium oxide) sprayed coating was provided as a cell forming layer on the peripheral surface of a base material roll made of ceramic (alumina), and a hatched cell was formed in this cell forming layer.

Outer diameter of base material roll (do): 60 mm
Inner diameter (di) of base material roll: 45 mm
Cell forming layer thickness: 50 μm
Gravure roll outer diameter (D); 60.1 mm
Gravure roll length (L): 1300mm
<Gravure roll b>
A DLC film (thickness: 2 μm) was further coated on the peripheral surface where the gravure roll a cell was formed by a plasma CVD method.

<Gravure roll c>
A ceramic (chromium oxide) sprayed coating was provided as a cell forming layer on the peripheral surface of a base material roll made of stainless steel, and a hatched cell was formed on this cell forming layer.

Outer diameter of base material roll (do): 60 mm
Inner diameter (di) of base material roll: 45 mm
Cell forming layer thickness: 50 μm
Gravure roll outer diameter (D); 60.1 mm
Gravure roll length (L): 1300mm
<Gravure roll d>
A ceramic (chromium oxide) sprayed coating was provided as a cell forming layer on the peripheral surface of a base material roll made of ceramic (alumina), and a hatched cell was formed in this cell forming layer.

Outer diameter of base material roll (do): 60 mm
Inner diameter (di) of base material roll: 45 mm
Cell forming layer thickness: 50 μm
Gravure roll outer diameter (D); 60.1 mm
Gravure roll length (L): 1800mm
<Gravure roll e>
A DLC film (thickness 2 μm) was further coated on the peripheral surface on which the gravure roll d cells were formed by a plasma CVD method.

<Gravure roll f>
A ceramic (chromium oxide) sprayed coating was provided as a cell forming layer on the peripheral surface of a base material roll made of stainless steel, and a hatched cell was formed on this cell forming layer.

Outer diameter of base material roll (do): 60 mm
Inner diameter (di) of base material roll: 45 mm
Cell forming layer thickness: 50 μm
Gravure roll outer diameter (D); 60.1 mm
Gravure roll length (L): 1800mm
[Composition for forming coating layer]
<Active energy ray-curable composition for forming coating layer a>
95 parts by mass of active energy ray-curable resin (including dipentaerythritol hexaacrylate and urethane acrylate oligomer (“Art Resin UN901T” manufactured by Negami Kogyo Co., Ltd.) at a mass ratio of 3: 7), and a photopolymerization initiator (Ciba -5 parts by mass of “Irgacure (registered trademark) 184” manufactured by Specialty Chemicals Co., Ltd. was dispersed or dissolved in an organic solvent (methyl ethyl ketone / methyl isobutyl ketone = 30/70 (mass ratio)). This composition had a viscosity (23 ° C.) of 7.0 mPa · s and a refractive index of 1.51.

<Active energy ray-curable composition for forming coating layer b>
Active energy ray curable resin (dipentaerythritol pentaacrylate) 50 parts by mass, fluorine compound (fluorine resin “AR110” manufactured by Daikin Industries, Ltd.) 45 parts by mass, photopolymerization initiator (Ciba Specialty Chemicals Irgacure 184) It was prepared by dispersing or dissolving 5 parts by mass in an organic solvent (a mixed solvent of methyl isobutyl ketone and propylene glycol monoethyl ether having a mass ratio of 1: 1). This composition had a viscosity (23 ° C.) of 2.0 mPa · s and a refractive index of 1.43.

[Example 1]
A laminated film was produced in the following manner.
<Lamination of coating layer>
Using the reverse gravure coating apparatus and gravure roll a of FIG. 4, an active energy ray-curable composition for forming the coating layer a was applied to a polyethylene terephthalate film (“Lumirror U48” manufactured by Toray Industries, Inc.). After drying at 90 ° C., UV rays were applied to cure at 400 mJ / cm ² to form a coating layer (hard coat layer) having a thickness of 2.5 μm. The coating width is 1200 mm.

[Examples 2 to 4 and Comparative Examples 1 to 2]
In Example 1, each laminated film was produced in the same manner as in Example 1 except that the type of gravure roll and the coating width were changed as shown in Table 1.

[Example 5]
A laminated film was produced in the same manner as in Example 1 except that the coating layer a was changed to the coating layer b and the thickness (dry thickness) of the coating layer b was changed to 0.1 μm. The coating layer b is an antireflection layer (low refractive index layer).

[Examples 6 to 8 and Comparative Examples 3 to 4]
In Example 5, each laminated film was produced in the same manner as in Example 5 except that the type of gravure roll and the coating width were changed as shown in Table 1.

[Evaluation]
About the laminated film manufactured by said Example and comparative example, the fluctuation | variation of the coating layer thickness in a coating width direction and a stripe-shaped defect were evaluated. The results are shown in Table 1.

DESCRIPTION OF SYMBOLS 1 Base material roll 2 Cell formation layer 3 Cell 4 Bank part 10 Gravure roll 11 Shaft part of gravure roll 20 Coating liquid supply means 21 Coating liquid storage container 22 Coating liquid 30 Doctor blade 41, 42 A pair of conveyance roller 50 Base film D Gravure roll outer diameter L Gravure roll length V Gravure roll deflection (maximum deflection due to its own weight)
do Outer diameter of base material roll inner diameter of base material roll t Thickness of base material roll

Claims (5)

  A gravure roll in which cells are formed on the peripheral surface of a cylindrical base material roll, the outer diameter of the gravure roll is 150 mm or less, the length of the gravure roll is 1100 mm or more, and the material of the base material roll is ceramic A gravure roll characterized by that.   The gravure roll according to claim 1, wherein the outermost surface of the peripheral surface of the gravure roll is coated with diamond-like carbon.   In the method for producing a laminated film in which a coating layer is laminated on a base film using a gravure roll, the gravure roll is a gravure roll in which cells are formed on the peripheral surface of a cylindrical base material roll, and the gravure roll A method for producing a laminated film, wherein the outer diameter of the substrate is 150 mm or less, the length of the gravure roll is 1100 mm or more, and the material of the base material roll is ceramic.   The manufacturing method of the laminated | multilayer film of Claim 3 with which the outermost surface of the surrounding surface of the said gravure roll is coat | covered with the diamond-like carbon.   The manufacturing method of the laminated | multilayer film of Claim 3 or 4 whose application width | variety is 1100 mm or more.

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