WO2012133390A1

WO2012133390A1 - Mold release treatment method, and antireflective film production method

Info

Publication number: WO2012133390A1
Application number: PCT/JP2012/057896
Authority: WO
Inventors: 箕浦　潔; 彰信石動
Original assignee: シャープ株式会社
Priority date: 2011-03-30
Filing date: 2012-03-27
Publication date: 2012-10-04

Abstract

A mold release treatment method which can be employed suitably for a mold having a porous alumina layer on the surface thereof. The mold release treatment method comprises the steps of: (a) preparing a mold release agent comprising a fluorine-containing compound having a mold release property and a solvent and a mold (100A) having a porous alumina layer (14) on the surface thereof; (b) applying the mold release agent onto the surface of the mold (100A); (c) removing the solvent contained in the mold release agent on the surface of the mold (100A); and (d), subsequent to the step (c), performing the steps (b) and (c).

Description

Mold release processing method and manufacturing method of antireflection film

The present invention relates to a mold release processing method and an antireflection film manufacturing method. The “mold” here includes molds used in various processing methods (stamping and casting), and is sometimes referred to as a stamper. It can also be used for printing (including nanoprinting).

2. Description of the Related Art An optical element such as a display device or a camera lens used for a television or a mobile phone is usually provided with an antireflection technique in order to reduce surface reflection and increase light transmission. For example, when light passes through the interface of a medium with a different refractive index, such as when light enters the interface between air and glass, the amount of transmitted light is reduced due to Fresnel reflection, etc., and visibility is reduced. is there.

In recent years, attention has been paid to a method for forming a fine uneven pattern on a substrate surface, in which the period of unevenness is controlled to a wavelength of visible light (λ = 380 nm to 780 nm) or less as an antireflection technique (see Patent Documents 1 to 4). reference). The two-dimensional size of the convex portions constituting the concavo-convex pattern exhibiting the antireflection function is 10 nm or more and less than 500 nm.

This method utilizes the principle of a so-called moth-eye structure, and the refractive index for light incident on the substrate is determined from the refractive index of the incident medium along the depth direction of the irregularities, to the refractive index of the substrate. The reflection in the wavelength region that is desired to be prevented from being reflected is suppressed by continuously changing the wavelength.

The moth-eye structure has an advantage that it can exhibit an antireflection effect with a small incident angle dependency over a wide wavelength range, can be applied to many materials, and can form an uneven pattern directly on a substrate. As a result, a low-cost and high-performance antireflection film (or antireflection surface) can be provided.

As a method for producing a moth-eye structure, a method using an anodized porous alumina layer obtained by anodizing aluminum is attracting attention (Patent Documents 2 to 4).

Here, the anodized porous alumina layer obtained by anodizing aluminum will be briefly described. Conventionally, a method for producing a porous structure using anodization has attracted attention as a simple method capable of forming regularly ordered nano-sized cylindrical pores (fine concave portions). When a substrate is immersed in an acidic or alkaline electrolyte such as sulfuric acid, oxalic acid, or phosphoric acid, and a voltage is applied using this as an anode, oxidation and dissolution proceed simultaneously on the surface of the substrate, and pores are formed on the surface. An oxide film having the following can be formed. These cylindrical pores are oriented perpendicular to the oxide film and exhibit self-organized regularity under certain conditions (voltage, type of electrolyte, temperature, etc.). Is expected.

The porous alumina layer formed under specific conditions takes an array in which almost regular hexagonal cells are two-dimensionally filled with the highest density when viewed from the direction perpendicular to the film surface. Each cell has a pore in the center, and the arrangement of the pores has periodicity. The cell is formed as a result of local dissolution and growth of the film, and dissolution and growth of the film proceed simultaneously at the bottom of the pores called a barrier layer. At this time, it is known that the distance between adjacent pores (center-to-center distance) corresponds to approximately twice the thickness of the barrier layer and is approximately proportional to the voltage during anodization. In addition, although the diameter of the pore depends on the type, concentration, temperature, etc. of the electrolyte, it is usually 1 / th of the cell size (the length of the longest diagonal of the cell when viewed from the direction perpendicular to the film surface). It is known to be about 3. The pores of such porous alumina have an arrangement with high regularity (having periodicity) under a specific condition, an arrangement with irregularity to some extent or an irregularity (having no periodicity) depending on the conditions. ).

Patent Document 2 discloses a method of forming an antireflection film (antireflection surface) using a stamper having an anodized porous alumina film on the surface.

Further, Patent Document 3 discloses a technique for forming a tapered concave portion in which the pore diameter continuously changes by repeating anodization of aluminum and pore diameter enlargement processing.

The present applicant discloses, in Patent Document 4, a technique for forming an antireflection film using an alumina layer in which fine concave portions have stepped side surfaces.

Further, as described in Patent Documents 1, 2, and 4, an antireflection film (antireflection surface) is provided by providing a concavo-convex structure (macro structure) larger than the moth eye structure in addition to the moth eye structure (micro structure). ) Can be given an anti-glare (anti-glare) function. The two-dimensional size of the projections that form the projections and depressions that exhibit the antiglare function is 1 μm or more and less than 100 μm. The entire disclosures of Patent Documents 1, 2, and 4 are incorporated herein by reference.

By using the anodized porous alumina film, a mold for forming a moth-eye structure on the surface (hereinafter referred to as “moth-eye mold”) can be easily manufactured. In particular, as described in Patent Documents 2 and 4, when the surface of an anodized aluminum film is used as it is as a mold, the effect of reducing the manufacturing cost is great. The surface structure of the moth-eye mold that can form the moth-eye structure is referred to as an “inverted moth-eye structure”.

As a method for producing an antireflection film using a moth-eye mold, a method using a photocurable resin is known. First, a photocurable resin is applied on the substrate. Subsequently, the uneven surface of the surface of the moth-eye mold is filled with the photocurable resin by pressing the uneven surface of the moth-eye mold subjected to the release treatment against the photocurable resin in a vacuum. Subsequently, the photocurable resin in the concavo-convex structure is irradiated with ultraviolet rays to cure the photocurable resin. Thereafter, by separating the moth-eye mold from the substrate, a cured product layer of a photocurable resin to which the concavo-convex structure of the moth-eye mold is transferred is formed on the surface of the substrate. A method for producing an antireflection film using a photocurable resin is described in Patent Document 4, for example.

As a mold release process having a porous alumina layer used for manufacturing an antireflection film, for example, Patent Document 5 describes performing a mold release process by applying a fluorine-based mold release agent by a spray coating method. Has been.

In addition, in Patent Document 6, when a lens is manufactured by a casting method, in order to uniformly apply a release agent to a mold, a release agent diluted with a solvent is applied only once, and then only a solvent is added. It is described that the thickness of the layer of the release agent can be made uniform throughout by providing the above.

JP-T-2001-517319 Special Table 2003-531962 JP 2005-156695 A International Publication No. 2006/059686 International Publication No. 2008/001847 JP 2005-270801 A International Publication No. 2011-111669

The present applicant has developed a method for efficiently producing an antireflection film by a roll-to-roll method using a roll-shaped moth-eye mold (for example, Patent Document 7). Fluorine-based release agents have better release properties than other release agents, such as silicone release agents, but the release properties are degraded in continuous production processes using the roll-to-roll method. However, it was found that it becomes a factor that hinders the improvement of mass production efficiency.

Here, the problem of the prior art has been described by exemplifying a roll-shaped moth-eye mold for an antireflection film, but the problem of low sustainability of mold release is a porous having a fine concave portion of submicron order. This is a problem common to molds having an alumina layer on the surface.

An object of the present invention is to improve the sustainability of mold releasability of a mold having a porous alumina layer on the surface.

A mold release treatment method according to an embodiment of the present invention includes (a) a step of preparing a mold release agent containing a fluorine compound having a mold release property and a solvent, and a mold having a porous alumina layer on the surface; ) Providing the mold release agent on the surface of the mold; (c) removing the solvent contained in the mold release agent on the surface of the mold; The step (b) and the step (c) are further included after the step (c).

In one embodiment, the method further includes the step (b) and the step (c) after the step (d). From the viewpoint of sustainability of releasability, it is preferable to perform the step (b) and the step (c) three times or more in total. Even if the step (b) and the step (c) are performed 4 times or more in total, the number of times is not particularly different from the case of 3 times, so 3 times is most preferable from the viewpoint of throughput and / or material cost. Finally, it is preferable to include a step of heating at a temperature of 50 ° C. or higher for 10 minutes or longer.

In one embodiment, the concentration of the fluorine compound contained in the release agent does not exceed 0.002 mol / L. When the concentration of the fluorine compound exceeds 0.002 mol / L, unevenness is likely to occur, and the effect of improving the releasability does not increase. On the other hand, the concentration of the fluorine compound is preferably 0.0004 mol / L or more. If the concentration of the fluorine compound is less than 0.0004 mol / L, sufficient releasability may not be obtained.

In one embodiment, the fluorine compound having releasability is perfluoropolyether-modified silane.

In one embodiment, the perfluoropolyether-modified silane is an alkoxysilane. For example, alkoxysilane is trimethoxysilane, and the fluorine-based compound has one or two or more trimethoxysilane in one molecule. The molecular weight of the fluorine-based compound is preferably 1000 or more and 10,000 or less.

In one embodiment, the mold is in a roll shape and has the porous alumina layer on the outer peripheral surface of the mold.

An antireflection film manufacturing method according to an embodiment of the present invention includes a step of preparing a mold subjected to a release treatment by any one of the above methods, a step of preparing a workpiece, the mold, A step of curing the photocurable resin by irradiating the photocurable resin with light in a state where the photocurable resin is provided between the surface of the workpiece and the photocurable resin obtained by curing the mold. And a step of peeling from the formed antireflection film.

In one embodiment, the workpiece is a roll film, and is performed in a roll-to-roll manner.

In one embodiment, the film includes a base film and a hard coat layer formed on the base film, and the antireflection film is formed on the hard coat layer.

According to the embodiment of the present invention, it is possible to improve the sustainability of mold releasability of a mold having a porous alumina layer on the surface. In addition, for example, mass production efficiency in manufacturing an antireflection film using a moth-eye mold can be increased.

It is a flowchart of the process in the mold release processing method of embodiment by this invention. (A)-(e) is a figure which shows the process of the manufacturing method of the type | mold which has a porous alumina layer. (A)-(e) is a figure which shows the process of the manufacturing method of the roll type | mold using a metal sleeve. It is sectional drawing which shows typically the structure of the type | mold 100A which has the metal sleeve 72m. It is a schematic diagram for demonstrating the manufacturing method of the antireflection film of embodiment by this invention. It is a figure which shows typically the process of forming an anti-reflective film in the film which has the base film 42a and the hard-coat layer 42b. It is a graph which shows the relationship between the frequency | count of transcription | transfer, and a contact angle about the type | mold from which the frequency | count of a mold release process (coat number) differs. It is a graph which shows the relationship between the frequency | count of transcription | transfer and a contact angle about the type | mold from which the frequency | count of a mold release process (coat number) and the type of mold release agent differ. (A) to (c) show SEM images of the surface of the mold subjected to the mold release treatment.

The mold release processing method according to the embodiment of the present invention will be described with reference to the drawings. Hereinafter, a moth-eye mold for producing an antireflection film will be described as an example.

FIG. 1 is a flowchart of steps in a mold release processing method according to an embodiment of the present invention. As shown in FIG. 1, the mold release processing method of embodiment by this invention is a process which prepares the mold release agent containing the fluorine-type compound and solvent which have mold release property, and the type | mold which has a porous alumina layer on the surface. (A), a step (b) of applying a release agent on the surface of the mold, a step (c) of removing a solvent contained in the release agent on the surface of the mold, and a step (c) Thereafter, the method further includes a step (b) of applying a release agent on the surface of the mold and a step (c) of removing a solvent contained in the release agent on the surface of the mold. In FIG. 1, “−1st” is added to the first step (b) and step (c), and “−−st” is added to the second step (b) and step (c) performed after the first step (c), respectively. 2nd ". Step (b) -2nd is typically performed under the same conditions as step (b) -1st, but the conditions may be changed. Similarly, step (c) -2nd is typically performed under the same conditions as step (c) -1st, but the conditions may be changed.

Further, as described later, step (b) -3rd and step (c) -3rd may be performed after step (b) -2nd and step (c) -2nd. Step (b) -3rd is typically the same step as step (b) -1st, similar to step (b) -2nd, but step (b) -1st and / or step (b) -2nd Different conditions may be used. Step (c) -3rd is typically the same step as step (c) -1st, similar to step (c) -2nd, but step (c) -1st and / or step (c) -2nd Different conditions may be used. From the viewpoint of sustainability of releasability, it is preferable to perform step (b) and step (c) three times or more (1st to 3rd) in total. However, even if the step (b) and the step (c) are performed 4 times or more in total, the number of times is not particularly different from the case of 3 times, so 3 times is most preferable from the viewpoint of throughput and / or material cost.

In this specification, a fluorine-based mold release agent refers to a mixture containing a releasable fluorine-based compound (fluorine-containing organic compound) and a solvent, and is generally a fluorine-based coating agent or a fluorine-based surface. Widely includes those marketed under names such as treatment agents. As the solvent for the fluorine-based mold release agent, a fluorine-based solvent is widely used, and the fluorine-based solvent is also a fluorine-based compound. A fluorine-based compound used as a fluorine-based solvent has low chemical activity, a relatively low molecular weight, and high volatility. In contrast, a fluorine-based compound having releasability has a hydrolyzable group such as alkoxylane, and generates a silanol group (SiOH) by hydrolysis. The silanol group has an affinity for the surface of the oxide and generates a bond such as a hydrogen bond. Silanol groups form a cross-linked structure by dehydration condensation to form a resin film of a fluorine-based compound. In order to distinguish the fluorine-based compound having releasability contained in the fluorine-based release agent from the fluorine-based solvent, it may be referred to as a fluorine-based release component.

As the fluorine-based releasable component, perfluoropolyether-modified silane is preferable, and alkoxysilane is particularly preferable. For example, it is preferable that the alkoxysilane is trimethoxysilane, and the fluorine-based releasable component has one or more trimethoxysilanes per molecule at the end of the molecule. The molecular weight of the fluorine-based releasable component is preferably 1000 or more and 10,000 or less.

According to the mold release processing method of the present embodiment, the sustainability of mold release can be greatly improved as will be shown later in an experimental example. The mechanism is considered as follows. The following mechanism is a consideration by the present inventor and does not limit the present invention.

Ideally, a monomolecular layer of a fluorine-based releasable component is formed on the surface of the mold by performing a mold release treatment on the surface of the mold. In addition, the fluorine-type mold release component which has trimethoxysilane at the terminal of a molecule | numerator can form a crosslinked structure after forming a monomolecular layer. For example, when perfluoropolyether-modified trimethoxysilane is used as the fluorine-based release component, ideally, the fluorine-based release component has the trimethoxylane end directed to the surface side of the mold, A monomolecular layer is formed with the polyether group facing the air side. However, in reality, the releasable components facing various directions aggregate and adhere to the surface of the mold as a lump. Here, “attachment” means that the solvent contained in the release agent is removed and the releasable component remains on the surface of the mold. When the releasable component aggregates, it cannot be densely attached to the fine recesses (or protrusions) formed on the surface of the porous alumina layer. In the second and subsequent release agent application steps, the solvent contained in the release agent removes the excessively attached (aggregated) release component from the surface, and the exposed mold surface. A mold release component adheres to the surface. In this way, by performing the step of applying the release agent twice or more, the releasable component can be more precisely attached to the surface of the porous alumina layer. When the concentration of the releasable component is increased, the releasable component easily aggregates. Therefore, the concentration of the releasable component is preferably not too high, and adjusted so as not to exceed 0.002 mol / L. Is preferred. In order to obtain sufficient releasability, the concentration of the fluorine-based releasable component is preferably 0.0004 mol / L or more.

As described in Patent Document 5, conventionally, a fluorine-based mold release agent has been widely used since it has excellent mold release properties and relatively high sustainability. Further, when the releasability is insufficient, the concentration of the fluorine-based releasable component in the release agent is increased. However, according to the study of the present inventor, as will be shown later in the experimental example, even if the concentration of the fluorine-based mold release component is increased, the effect of improving the sustainability of the mold release is scarce, rather, unevenness (non-uniformity) ) Occurs. Moreover, as described in Patent Document 6, even if only the solvent is applied after the release agent is applied, the sustainability of the release property is not improved. As in this embodiment, a porous alumina layer having a large number of fine recesses is used as a mold, and as shown in an experimental example using a roll mold, when it is used repeatedly continuously, the separation is performed at a higher level than before. It is considered that the persistence of type is required.

The mold according to the embodiment of the present invention is suitably used for manufacturing an antireflection film (antireflection surface). The cross-sectional shape of the fine recesses (pores) of the porous alumina layer used for manufacturing the antireflection film is generally conical. It is preferable that the two-dimensional size (opening portion diameter: D _p ) of the fine recess is 10 nm or more and less than 500 nm and the depth (D _depth ) is about 10 nm or more and less than 1000 nm (1 μm). Moreover, it is preferable that the bottom part of a fine recessed part is sharp (the bottom is a point). Furthermore, it is preferable that the fine recesses are closely packed, and assuming that the shape of the fine recesses when viewed from the normal direction of the porous alumina layer is a circle, the adjacent circles overlap each other, and the adjacent fine It is preferable that a flange is formed between the concave portions. When the substantially conical minute recesses are adjacent so as to form a collar portion, the two-dimensional size D _p of the minute recess is assumed to be equal to the average adjacent distance D _int . Therefore, the moth-eye type porous alumina layer for producing the antireflection film has a dense concave portion with D _p = D _int of 10 nm or more and less than 500 nm and D _depth of 10 nm or more and less than 1000 nm (1 μm). It is preferable to have a regularly arranged structure. Since the shape of the opening of the fine recesses is not a circle strictly, D _p is preferably determined from the SEM image of the surface. The thickness t _p of the porous alumina layer is about 1 μm or less.

The mold according to the embodiment of the present invention can be formed by using an aluminum film deposited on a substrate, or can be formed by using an aluminum bulk material (for example, an aluminum substrate, an aluminum cylinder or a cylinder). it can. The mold is, for example, a roll and has a porous alumina layer on the outer peripheral surface of the mold. The roll-shaped mold has an advantage that the surface structure of the mold can be continuously transferred to a workpiece (an object having a surface on which an antireflection film is formed) by rotating the roll-shaped mold around an axis. is there.

An antireflection film manufacturing method according to an embodiment of the present invention includes a step of preparing a mold that has been subjected to a mold release treatment by any of the above methods, a step of preparing a workpiece, and a mold and a workpiece. A mold is formed from a step of curing the photocurable resin by irradiating the photocurable resin with light in a state where the photocurable resin is applied between the surface and the antireflection film formed of the cured photocurable resin. And a peeling step.

When a roll-shaped film is used as a workpiece, an antireflection film can be produced by a roll-to-roll method. The film preferably has a base film and a hard coat layer formed on the base film, and the antireflection film is preferably formed on the hard coat layer. As the base film, for example, a TAC (triacetyl cellulose) film can be suitably used. As the hard coat layer, for example, an acrylic hard coat material can be used.

The following is an experimental example.

For the experiment, a small plate type and a roll type were prepared.

The small plate type is a 5 cm × 5 cm square, and a substrate obtained by depositing an aluminum film having a thickness of about 1 μm by sputtering on a glass substrate (Corning Corporation 1737) having a thickness of 0.7 mm is used as a base material. As described above, it was produced by alternately repeating anodic oxidation and etching. An example of a method for manufacturing a mold having a porous alumina layer will be described with reference to FIGS.

First, as shown in FIG. 2A, a mold base 10 is prepared. The mold base 10 has a support (not shown), an insulating layer 16 formed on the support, and an aluminum layer 18 deposited on the insulating layer 16. An aluminum alloy layer may be used in place of the aluminum layer 18.

Next, as shown in FIG. 2B, the porous alumina layer 14 having a plurality of pores 14p (fine concave portions) is formed by anodizing the surface of the substrate 10 (the surface 18s of the aluminum layer 18). To do. The porous alumina layer 14 has a porous layer having pores 14p and a barrier layer. The porous alumina layer 14 is formed, for example, by anodizing the surface 18s in an acidic electrolytic solution. The electrolytic solution used in the step of forming the porous alumina layer 14 is an aqueous solution containing an acid selected from the group consisting of oxalic acid, tartaric acid, phosphoric acid, chromic acid, citric acid, and malic acid, for example. By adjusting the anodic oxidation conditions (for example, the type of electrolytic solution and the applied voltage), the pore spacing, pore depth, pore shape, and the like can be adjusted. The thickness of the porous alumina layer 14 can be changed as appropriate. The aluminum layer 18 may be fully anodized.

Next, as shown in FIG. 2 (c), the porous alumina layer 14 is brought into contact with an alumina etchant and etched by a predetermined amount to enlarge the pore diameter of the pores 14p. Here, by employing wet etching, the pore walls and the barrier layer can be etched almost isotropically. The amount of etching (that is, the size and depth of the pores 14p) can be controlled by adjusting the type / concentration of the etching solution and the etching time. As the etching solution, for example, an aqueous solution of 10% by mass of phosphoric acid, an organic acid such as formic acid, acetic acid or citric acid, or a mixed solution of chromium phosphoric acid can be used.

Next, as shown in FIG. 2D, the aluminum layer 18 is partially anodized again to grow the pores 14p in the depth direction and to thicken the porous alumina layer 14. Here, the growth of the pores 14p starts from the bottom of the already formed pores 14p, so that the side surfaces of the pores 14p are stepped.

Thereafter, if necessary, the porous alumina layer 14 is further etched by bringing it into contact with an alumina etchant to further expand the pore diameter of the pores 14p. As the etchant, it is preferable to use the above-described etchant, and in practice, the same etch bath may be used.

As described above, by repeating the above-described anodizing step and etching step, a moth-eye mold 100A having a porous alumina layer 14 having a desired concavo-convex shape is obtained as shown in FIG.

For example, a porous alumina layer having D _int = D _p = 180 nm, D _depth = 300 nm, t _p = 400 nm, and a barrier layer thickness t _b of about 100 nm can be formed as follows.

An aluminum layer (thickness: about 1 μm) deposited on a glass substrate was anodized for 60 seconds at a formation voltage of 80 V using 0.1 M oxalic acid aqueous solution (18 ° C.) as an electrolytic solution, and then 2 masses as an etching solution. The anodic oxidation layer formed by the previous anodic oxidation process is removed by immersing in a phosphoric acid aqueous solution (30 ° C.) for 90 minutes. Since the fine concavo-convex structure of the initially formed porous alumina layer is often not constant, the porous alumina layer may be formed again after removing the initially formed porous alumina layer in order to improve reproducibility. preferable.

Thereafter, the anodizing step (5 times) and the etching step (4 times) are alternately repeated using the above electrolytic solution (the temperature is the same) and the etching solution (the same temperature). Here, the cycle in which anodization and etching are alternately performed ends with the anodization step. The time of one anodic oxidation process is 25 seconds, and the time of one etching process is 19 minutes.

The roll mold was prepared by the method described in International Publication No. 2011/105206 by the applicant. Here, a stainless steel or nickel metal sleeve was used. The metal sleeve refers to a metal cylinder having a thickness of 0.02 mm to 1.0 mm. The entire disclosure of WO 2011/105206 is incorporated herein by reference.

A roll type manufacturing method using a metal sleeve used in the experiment will be briefly described with reference to FIG.

First, as shown in FIG. 3A, a metal sleeve 72m and a curable resin (not shown) are prepared.

Next, as shown in FIG. 3B, a curable resin layer 16 'is formed by applying a curable resin on the outer peripheral surface of the metal sleeve 72m. As the curable resin, for example, a resin containing polyamic acid can be used.

Next, the curable resin layer 16 ′ is cured to form the insulating layer 16 on the outer peripheral surface of the metal sleeve 72 m as shown in FIG. For example, when thermosetting polyamic acid is used as the curable resin, the insulating layer 16 made of polyimide resin is formed by heating to about 300 ° C.

The insulating layer 16 can also be formed by, for example, an electrodeposition method. As the electrodeposition method, for example, a known electrodeposition coating method can be used. For example, first, the metal sleeve 72m is cleaned. Next, the metal sleeve 72m is immersed in an electrodeposition tank in which an electrodeposition liquid containing an electrodeposition resin is stored. Electrodes are installed in the electrodeposition tank. When the insulating resin layer is formed by cationic electrodeposition, the metal sleeve 72m is used as a cathode, the electrode installed in the electrodeposition tank is used as an anode, a current is passed between the metal sleeve 72m and the anode, and the metal sleeve 72m is used. An insulating resin layer is formed by depositing an electrodeposition resin on the outer peripheral surface of the film. When the insulating resin layer is formed by anion electrodeposition, the insulating resin layer is formed by flowing an electric current with the metal sleeve 72m as an anode and the electrode installed in the electrodeposition tank as a cathode. Thereafter, the insulating layer 16 is formed by performing a cleaning process, a baking process, and the like. As the electrodeposition resin, for example, a polyimide resin, an epoxy resin, an acrylic resin, a melamine resin, a urethane resin, or a mixture thereof can be used.

In addition to the electrodeposition method, the insulating layer 16 can be formed by forming an insulating resin layer using various coating methods and curing as necessary. The insulating layer 16 formed using an organic resin has a high effect of flattening the surface, and can suppress the surface scratches of the metal sleeve 72 m and the like from being reflected on the surface shape of the aluminum layer 18.

Further, for example, the insulating layer 16 having a surface having antiglare property can be formed by mixing a matting agent with the electrodeposition resin. For example, by mixing a matting agent with an acrylic melamine resin, for example, a two-dimensional spread (substantially circular) when viewed from the normal direction of the layer is approximately 20 μm, and a convex portion having a height of less than 1 μm is formed. A formed surface can be obtained.

Next, as shown in FIG. 3D, an aluminum layer 18 is formed by depositing aluminum on the insulating layer 16 by a thin film deposition method.

Subsequently, as shown in FIG. 3 (e), by alternately repeating anodic oxidation and etching on the surface of the aluminum layer 18, the porous alumina layer 14 having a plurality of fine recesses is formed. The mold 100a is obtained.

Since the metal sleeve 72m is easily deformed, it is difficult to use the mold 100a as it is. Therefore, as shown in FIG. 4, by inserting the core material 50 into the metal sleeve 72m of the mold 100a, a mold 100A that can be used in a roll-to-roll antireflection film manufacturing method is obtained. In the mold 100 </ b> A, the core material 50, the metal sleeve 72 m, and the insulating layer 16 function as the support 12.

Next, with reference to FIG. 5, a method of manufacturing the antireflection film according to the embodiment of the present invention will be described. FIG. 5 is a schematic cross-sectional view for explaining a method for producing an antireflection film by a roll-to-roll method.

First, the roll-shaped moth-eye mold 100A shown in FIG. 4 is prepared.

Next, as illustrated in FIG. 5, the ultraviolet curable resin 32 ′ is irradiated with ultraviolet rays (UV) in a state where the workpiece 42 having the ultraviolet curable resin 32 ′ applied to the surface thereof is pressed against the moth-eye mold 100 </ b> A. As a result, the ultraviolet curable resin 32 'is cured. As the ultraviolet curable resin 32 ′, for example, an acrylic resin can be used. The workpiece 42 is, for example, a TAC (triacetyl cellulose) film. The workpiece 42 is unwound from an unillustrated unwinding roller, and then an ultraviolet curable resin 32 ′ is applied to the surface by, for example, a slit coater. The workpiece 42 is supported by

support rollers

62 and 64 as shown in FIG. The

support rollers

62 and 64 have a rotation mechanism and convey the workpiece 42. The roll-shaped moth-eye mold 100A is rotated in the direction indicated by the arrow in FIG. 5 at a rotation speed corresponding to the conveyance speed of the workpiece 42.

Thereafter, by separating the moth-eye mold 100A from the workpiece 42, a cured product layer 32 to which the uneven structure (inverted moth-eye structure) of the moth-eye mold 100A is transferred is formed on the surface of the workpiece 42. . The workpiece 42 having the cured product layer 32 formed on the surface is wound up by a winding roller (not shown).

Here, as shown in FIG. 6, when a film having a base film 42a made of a TAC film and a hard coat layer 42b formed on the TAC film 42a is used as the workpiece 42, the hard coat layer 42b is used. And the mold 100A may come into contact with each other. According to experiments, the mold 100A is in contact with the hard coat layer (cured simultaneously with the ultraviolet curable resin 32 ′) 42b as well as the portion in contact with the ultraviolet curable resin 32 ′ for forming the antireflection layer. Even in the portion, there was a defect that the porous alumina layer 14 of the mold 100A was peeled off.

Therefore, in the following experiment, not only the releasability with respect to the ultraviolet curable resin for the antireflection film but also the releasability with respect to the ultraviolet curable resin for the hard coat were evaluated together.

As the photocurable resin for forming the antireflection film, an ultraviolet curable acrylic resin containing (1% by mass) a fluorine-based lubricant having a perfluoro group having 6 or less carbon atoms was used. Further, as a resin for forming the hard coat layer, an ultraviolet curable acrylic resin for hard coat was used.

As the fluorine-based mold release agent, a product containing a trade name Fluorosurf FG-5010 (fluorine-based mold release component) manufactured by Fluoro Technology and ZV (also referred to as a solvent or diluent) manufactured by Fluoro Technology was used. . The concentration of the fluorine-based mold release agent was appropriately adjusted from 0.1% by mass to 1.0% by mass. The number average molecular weight of the fluoro-type releasable component of Fluorosurf FG-5010 used here was about 4000 to about 5000. When the specific gravity of the solution is 1.5 and the molecular weight of the fluorine number releasable component is 4000 g, 0.1% by mass corresponds to 0.0004 mol / L.

The mold release process was performed as follows.

(1) With the mold 100a shown in FIG. 3 (e) (cylinder diameter 300 mm, cylindrical axial length 100 cm or 150 cm) held vertically, a mold release agent is applied using a washing bottle. A mold release agent is sprayed as needed to keep the surface of the mold 100a wet for 5 minutes.

(2) Next, the solvent is removed. The mold 100a to which the release agent is applied is dried from the end by air blow while rotating around the axis of the cylinder.

After this, repeat the above (1) and (2) once, twice or four times as necessary.

Finally, blow hot air over the entire surface with an industrial dryer for 30 minutes. At this time, the surface of the mold 100a is about 50 ° C. to about 60 ° C. at the maximum.

In this way, molds coated with the release agent once, twice, three times and five times were prepared. Here, the mold 100a has an insulating layer 16 formed by electrodeposition using a material obtained by adding a matting agent to an acrylic melamine resin, and the surface of the porous alumina layer is viewed from the normal direction of the layer. A mold having a convex portion with a two-dimensional spread of about 20 μm and a height of less than 1 μm was used. When this mold is used, an antireflection film having antiglare properties can be formed.

Evaluation of mold releasability was performed as follows.

The contact angle of the mold surface with water was measured using a contact angle meter DropMaster 500 manufactured by Kyowa Interface Chemical Co., Ltd. The amount of water dropped was 3.0 microliters. With 3.0 microliters of water droplet held on the needle tip of the microsyringe, the water droplet was brought into contact with the surface of the mold, and then the needle was retracted, so that the water droplet adhered and remained on the surface of the mold. The contact angle of water droplets remaining on the surface of the mold was measured with the above contact angle meter.

Using the mold 100A including the mold 100a subjected to the above-described mold release treatment, an antireflection film was continuously formed by a roll-to-roll method, and the sustainability of the mold release property was evaluated. The change in contact angle of the mold surface with water relative to the number of times of transfer (the number of rotations of the roll-shaped mold) was determined. Table 1 and FIG. 7 show the results when an ultraviolet curable acrylic resin for forming an antireflection film is used as the photocurable resin. The concentration of the releasable component is 0.1% by mass.

As apparent from Table 1 and FIG. 7, compared to the one-time coating type, both the two-time coating type, the three-time coating type, and the five-time coating type have a small decrease in the contact angle with an increase in the number of transfer times. It can be seen that the durability of releasability can be improved by coating more than once.

Similarly, the evaluation results of the ultraviolet curable acrylic resin for hard coat are shown in Table 2 below. Table 3 shows the results of evaluating the amount (area) of the adhesive remaining on the surface of the mold after the scotch tape (trade name 313) was attached to the surface of the mold and peeled off.

Referring to Table 2, when the number of times of transfer is about 10, there is no difference in releasability between the once-coated type, the twice-coated type, and the three-time coated type. However, as can be seen from Table 3, the remaining amount of the adhesive after the 10th transfer has a clear difference between the 1st coat type, the 2nd coat type, and the 3rd coat type. Later, the three-time coat type has excellent releasability.

As can be seen from the above results, it can be seen that the sustainability of releasability can be improved by applying the release agent twice or more (Table 1 etc.). Moreover, it turns out that the sustainability of a mold release property can be improved further by giving a mold release agent 3 times (Table 3).

In FIG. 8, a fluorine-based mold release agent containing 0.1% by mass of an optool made by Daikin Industries, Ltd. is prepared. The result of having evaluated sex is shown. The mold release process was performed as follows.

(1) A mold release agent is applied with a spoid while the small plate type is held almost vertically.

(2) Then, leave it for 3 minutes and remove the solvent by natural drying. During natural drying, it was visually observed that the boundary line between the part where the solvent was removed and the part where the solvent remained moved from the upper end to the lower end of the small plate type.

After this, repeat the above (1) and (2) twice as necessary.

Finally, the small plate type is placed on a hot plate and heated at 100 ° C. for 15 minutes.

In this way, a mold coated with a release agent once and three times was produced.

As can be seen from FIG. 8, when the OPTOOL is used, the three-time coating type has higher releasability than the one-time coating type.

The concentration of the releasable component of the release agent used in the above experimental example was 0.1% by mass (0.0004 mol / L). A mold release agent having a concentration of the release agent component (Fluorosurf FG-5010) of 0.1% by mass, 0.5% by mass, 0.7% by mass, and 1.0% by mass is used with respect to the above-described small plate type. Then, the mold release treatment was performed in the same manner as described above, and the surface state of the mold and the sample of the antireflection film produced using each mold was visually evaluated. A sample of the antireflection film was prepared by applying an ultraviolet curable acrylic resin for the antireflection film to the surface of the mold, then extending the acrylic resin using a roller with a PET film placed on top, and then fusion D Using a lamp, ultraviolet rays of 100 mW / cm ² (wavelength 365 nm) were irradiated for 15 seconds.

As a result of the above experiment, when the concentration of the releasable component was 0.7% by mass or more, unevenness was observed on both the surface of the mold and the surface of the antireflection film sample. When the antireflection film sample was attached to the black acrylic plate and observed, unevenness was more easily observed in the antireflection film sample than in the mold. In addition, when the concentration of the releasable component is 0.7% by mass or more, the above-mentioned unevenness is generated even if the release agent is applied and left for 3 minutes and then washed with a solvent contained in the release agent. It could not be prevented. 9 (a) to 9 (c) show SEM images of the surface of a mold coated three times with a mold release agent containing 1.0% by mass of a mold release component. The unevenness seen in FIGS. 9 (a) to 9 (c) seems to be due to the aggregation and uneven distribution of the releasable components.

On the other hand, when a release agent having a release component concentration of 0.1% by mass and 0.5% by mass was used, no unevenness was observed even when coating was performed three times. From this, it can be said that the concentration of the releasable component in the release agent is preferably not more than 0.5% by mass (0.002 mol / L). The lower limit is appropriately set, but it is considered that the concentration of the releasable component is preferably 0.1% by mass (0.0004 mol / L) or more.

The present invention is suitably used for producing a mold having a porous alumina layer and an antireflection film using the same.

12 Support 14 Porous Alumina Layer 14p Pore (Fine Concave)
16 Insulating layer 18 Aluminum layer or aluminum alloy layer 18s Surface of aluminum layer 32 'UV curable resin 32 Cured material layer 42 Work piece 42a Base film 42b Hard coat layer 50

Core material

100a, 100A Moss eye mold

Claims

(A) preparing a mold release agent containing a fluorine-based compound having a releasability and a solvent, and a mold having a porous alumina layer on the surface;
(B) providing the mold release agent on the surface of the mold;
(C) removing the solvent contained in the release agent on the surface of the mold;
(D) A mold release processing method further including the step (b) and the step (c) after the step (c).
The mold release processing method according to claim 1, further comprising the step (b) and the step (c) after the step (d).
The mold release treatment method according to claim 1 or 2, wherein the concentration of the fluorine compound contained in the mold release agent does not exceed 0.002 mol / L.
The mold release treatment method according to any one of claims 1 to 3, wherein the fluorine-based compound having releasability is perfluoropolyether-modified silane.
The mold release treatment method according to claim 4, wherein the perfluoropolyether-modified silane is an alkoxysilane.
Preparing a mold subjected to a mold release treatment by the method according to claim 1;
A step of preparing a workpiece;
Curing the photocurable resin by irradiating the photocurable resin with light in a state where the photocurable resin is applied between the mold and the surface of the workpiece;
A method for producing an antireflection film, comprising a step of peeling the fluorine-based mold release component formed of a cured photocurable resin.