JP2015052724A - Micro concavo-convex film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a micro concavo-convex film which has an anti-reflection property, reduces visibility of scratches making them less obvious, and can be used on display panels, touch panels, and optical members.SOLUTION: A micro concavo-convex film 40 has a portion 1 with a micro concavo-convex structure on a surface thereof and a plurality of flat and smooth portions 2, where the proportion of the flat and smooth portions 2 to a total surface area is greater than 10% and no greater than 50%. The flat and smooth portions 2 preferably have height that is similar to height of valleys in the portion 1 with the micro concavo-convex structure, and an area of each flat and smooth portion 2 is preferably no greater than 0.01 mm.

Description

  The present invention relates to a film having a fine uneven shape on the surface.

In recent years, for the purpose of imparting antireflection properties, antifogging properties, antifouling properties, water repellency, and the like, molded bodies such as functional films having a fine concavo-convex structure on the surface have been proposed. In particular, it is known that a fine concavo-convex structure called a Moth-Eye structure exhibits excellent antireflection properties.
As a method for forming a fine concavo-convex structure on the surface of a molded body, a method for directly processing the surface of a material, a transfer method for transferring the structure using a stamper (mold) having an inverted structure corresponding to the fine concavo-convex structure, etc. The latter method is superior in terms of productivity and economy. As a method for forming an inversion structure on a stamper, an electron beam drawing method, a laser beam interference method, and the like are known. However, as a method for forming an inversion structure more easily in recent years, the surface of an aluminum substrate is anodized. The method is drawing attention.

Anodized alumina formed by anodizing the surface of an aluminum substrate is an aluminum oxide film (alumite) and has a fine concavo-convex structure consisting of a plurality of recesses (pores) whose period is not more than the wavelength of visible light Have
In addition, a molded body having a fine concavo-convex structure on its surface is excellent in antireflection properties, but slight defects such as chipping and scratches on the surface of the molded body may be noticeable. Forming bodies with higher pillars have also been proposed. For example, Patent Document 1 discloses a structure in which an AR lattice in which a large number of fine protrusions are periodically formed and protective pillars that are scattered between the protrusions and are higher than the height of the protrusions are disclosed. .
However, since the molded article described in Patent Document 1 has columns higher than the fine concavo-convex structure, the fine concavo-convex structure is not in direct contact and has excellent scratch resistance, but when used as the outermost surface, the pillar itself Defects in the molded product such as chipping and scratches on the surface were sometimes noticeable.

Japanese Patent No. 4262944

  The present invention provides a fine concavo-convex film having an antireflection property and being less noticeable of scratches by having a portion having a fine concavo-convex structure and a smooth portion.

As a result of intensive studies, the present inventors have found that by having a smooth portion at a position equivalent to the bottom of the valley portion of the portion having a fine concavo-convex structure, the visibility of the scratches is lowered, making it difficult to stand out. It came to complete.
That is, the fine uneven film of the present invention has a portion having a fine uneven structure on the surface and a smooth portion, and the ratio of the area of the smooth portion to the total surface area is more than 10% and less than 50%. It is a fine uneven film.
Moreover, it is a fine uneven | corrugated film characterized by the height of the said smooth part being a position equivalent to the valley bottom part of the part which has the said fine uneven structure.
Moreover, it is a fine uneven | corrugated film characterized by the area per one said smooth part being 0.01 mm < ² > or less.
The fine concavo-convex structure preferably includes a plurality of convex portions having an average height of 80 to 500 nm and a period of 20 to 400 nm.
Furthermore, it is the article | item provided with the said fine uneven | corrugated film, and the manufacturing method of the said fine uneven | corrugated film.

  ADVANTAGE OF THE INVENTION According to this invention, the fine uneven | corrugated film and articles | goods which have antireflective property and are not conspicuous of a damage | wound are obtained.

It is a cross-sectional schematic diagram of an example of the fine uneven | corrugated film of this invention. It is a schematic diagram of the manufacturing process of an example of the stamper which uses the fine uneven | corrugated film of this invention for manufacture. It is a schematic diagram of an example of the fine uneven structure of the stamper used for this invention. It is a cross-sectional schematic diagram of an example of the stamper surface which uses the fine uneven | corrugated film of this invention for manufacture. It is a schematic diagram of an example of the apparatus for manufacturing the fine uneven | corrugated film of this invention.

  Hereinafter, the present invention will be described in detail with reference to the drawings. 1 to 5, each member has a different scale so that each member has a size that can be recognized on the drawing. In the present specification, “(meth) acrylate” means acrylate and methacrylate. “(Co) polymer” means a polymer and a copolymer.

[Fine uneven film]
The fine uneven film of the present invention has a portion having a fine uneven structure on the surface and a plurality of smooth portions, and the ratio of the area of the smooth portion to the total surface area is greater than 10% and 50% or less. If the ratio of the area of the smooth part with respect to the total surface area is larger than 10%, the scratches on the fine uneven film become inconspicuous. On the other hand, if the area ratio is 50% or less, the antireflection performance is good and the visibility is improved. Preferably they are 15% or more and 40% or less.
It is preferable that the fine uneven | corrugated film of this invention is a position where the height of a smooth part is a height equivalent to the valley bottom part of the part which has a fine uneven structure. Since the smooth portion is at the same height as the valley bottom portion of the portion having the fine concavo-convex structure, damage to the smooth portion can be suppressed.
Moreover, it is preferable that the fine uneven | corrugated film of this invention is 0.01 mm < ² > or less per one area of a smooth part. Area per flat part one, in that it is not the size of it is visible, preferably 0.01 mm ² or less, 0.0025 mm ² or less being more preferred.

The fine concavo-convex structure of the fine concavo-convex film of the present invention preferably comprises a plurality of convex portions having an average height of 80 to 500 nm and a period of 20 to 400 nm. If the period of the fine concavo-convex structure (the average (average interval) of the intervals P ′ from the center of the convex part 41 in FIG. 1 to the convex part 41 adjacent thereto) is not more than the wavelength of visible light, that is, 400 nm or less, An effective antireflection function can be exhibited. Moreover, if the height of the convex portion 41 (the vertical distance H from the tip of the convex portion 41 in FIG. 1 to the bottom portion of the adjacent concave portion 42) is 80 to 500 nm, the reflectance is further reduced.
The fine concavo-convex structure may be provided on the entire surface of the fine concavo-convex film 40 or may be provided on a part of the surface. The entire surface of one surface of the fine uneven film 40 may be provided with a transfer surface, or may be provided on a part of one surface. Further, the transfer surface may or may not be provided on the other surface.

The smooth part of the fine concavo-convex film of the present invention is a part which does not have a convex part having a height as in the fine concavo-convex structure. The height of the smooth portion is preferably at the same position as the valley bottom of the portion having the fine concavo-convex structure. Specifically, the height of the smooth portion from the valley bottom of the portion having the fine concavo-convex structure is preferably 50 nm or less, more preferably 10 nm or less, and particularly preferably 0.1 nm or less.
As shown in the smooth portion 2 of FIG. 1, the length of the smooth portion 2 when the fine uneven film is viewed from the cross section is preferably 0.1 mm or less, and more preferably 0.05 mm or less. The shape of the smooth portion is not particularly limited.
The fine concavo-convex film of the present invention described above can produce an article having antireflection properties, low visibility of scratches, and inconspicuousness.

[Manufacturing method of stamper]
Although the manufacturing method of the fine uneven | corrugated film of this invention does not have a restriction | limiting in particular, It is preferable to use the stamper by which the fine uneven structure was formed on the aluminum base material by anodic oxidation from a viewpoint of antireflection performance and productivity.
In the present invention, the “period” of the concavo-convex structure is the average (average interval) of the distance from the center of the concave portion (or convex portion) constituting the concavo-convex structure to the concave portion (or convex portion) adjacent thereto. is there.

<Aluminum substrate>
As the aluminum substrate, an aluminum substrate having a work surface on which a fine concavo-convex structure is formed, which is used for manufacturing a stamper having a fine concavo-convex structure on its surface, is used. The surface to be processed is a surface that comes into contact with the body of the molded body when the surface of the stamper is transferred to the surface of the body of the molded body.
The purity of the aluminum substrate 10 is preferably 98% by mass or more, more preferably 99% by mass or more, and further preferably 99.9% by mass or more. When the purity is less than 98% by mass, there is a tendency that pores are not formed during anodization, or the shape of the pores is not vertical even if formed. A stamper manufactured from such an aluminum substrate having a purity of less than 98% by mass is not suitable for manufacturing an antireflection article, for example.
The aluminum substrate may be mirror-finished by a method such as mechanical polishing, feather polishing, or electrolytic polishing before being used for manufacturing a stamper described later.

<Manufacture of stampers>
In the present invention, the above-described aluminum substrate is used, and after masking a region of more than 10% and less than 50% of the processed surface of the aluminum substrate, the treated surface is anodized to obtain a fine uneven structure and a smooth surface. A stamper is manufactured by forming a structure in which is formed on the surface of an aluminum substrate.
Hereinafter, each step will be described in detail.

(Masking process)
As a method for masking the aluminum substrate, a known method can be adopted, and specifically, an ink jet or the like can be used.
By masking the aluminum base material, as shown in FIG. 4, the area ratio of the aluminum base material 10 to the masked processed surface is greater than 10% and less than 50%, and the area per one is A region 17 that is 0.01 mm ² or less is formed. If the area ratio is larger than 10%, the scratches on the fine uneven film become inconspicuous. On the other hand, if the area ratio is less than 50%, the antireflection performance is good and the visibility is improved. Area, in that it is not the size of it is visible, preferably 0.01 mm ² or less, 0.0025 mm ² or less being more preferred.

(anodization)
As a method of anodizing the treated surface of the aluminum substrate, a method of sequentially performing the following steps is preferable.
First oxide film forming step (a);
The treated surface of the aluminum substrate is anodized in an electrolytic solution to form an oxide film on the treated surface (hereinafter also referred to as step (a)).
Oxide film removal step (b);
The oxide film is removed, and pore generation points for anodic oxidation are formed on the treated surface (hereinafter also referred to as step (b)).
Second oxide film forming step (c);
The treated surface of the aluminum base material on which the pore generation point is formed is anodized again in the electrolytic solution to form an oxide film having pores corresponding to the pore generation point on the surface to be processed (hereinafter, step ( Also referred to as c)).
Pore diameter expansion treatment step (d);
The diameter of the pores is enlarged (hereinafter also referred to as step (d)).
Repeating step (e);
If necessary, the second oxide film forming step (c) and the pore diameter expansion treatment step (d) are repeated (hereinafter also referred to as step (e)).

Step (a):
In the step (a), the treated surface of the aluminum base material is anodized under a constant voltage in an electrolytic solution, and the treated surface of the aluminum base material 10 is oxidized with pores 11 as shown in FIG. 2 (a). A film 12 is formed. Examples of the electrolytic solution include sulfuric acid, an oxalic acid aqueous solution, and a phosphoric acid aqueous solution.
Step (b):
In the step (b), by removing the oxide film 12 formed in the step (a), as shown in FIG. 2B, it corresponds to the bottom of the removed oxide film 12 (referred to as a barrier layer). Periodic depressions, that is, pore generation points 13 are formed. By forming the pore generation points 13 for anodization, the regularity of the pores finally formed can be improved.
Examples of the method for removing the oxide film 12 include a method in which aluminum is not dissolved but is removed with a solution that selectively dissolves alumina. Examples of such a solution include a chromic acid / phosphoric acid mixed solution.

Step (c):
In the step (c), the aluminum base material 10 on which the pore generation points 13 are formed is anodized again under a constant voltage in the electrolytic solution, and an oxide film is formed again. Thereby, as shown in FIG.2 (c), the oxide film 15 in which the cylindrical pore 14 was formed can be formed. Examples of the electrolytic solution include the same as in step (a).
Step (d):
In the step (d), a pore diameter enlargement process is performed to enlarge the diameter of the pores 14 formed in the step (c), and as shown in FIG. ) To expand the diameter.
As a specific method of the pore diameter expansion treatment, a method of immersing in a solution dissolving alumina and expanding the diameter of the pores formed in the step (c) by etching can be mentioned. Examples of such a solution include a phosphoric acid aqueous solution of about 5% by mass. The longer the time of step (d), the larger the pore diameter.
Step (e):
In the step (e), the step (c) is performed again, and the shape of the pores 14 is changed to a two-stage cylindrical shape having different diameters, as shown in FIG. 2 (e), and then the step (d) is performed again. I do. By repeating the step (c) and the step (d) as described above, as shown in FIG. 2 (f), the pores having a shape in which the diameter continuously decreases in the depth direction from the opening as shown in FIG. 2 (f). Thus, a stamper 20 having anodized alumina (a porous oxide film (alumite) of aluminum) having 14 is obtained.

By appropriately setting the conditions of the step (c) and the step (d), for example, the time for anodization and the time for the pore size expansion treatment, pores having various shapes can be formed. Therefore, these conditions may be appropriately set according to the use of the fine uneven film to be manufactured from the stamper. In addition, when this stamper is for manufacturing an antireflection article such as an antireflection film, the period and depth of the pores can be arbitrarily changed by appropriately setting the conditions in this way, so that the optimum It is also possible to design a refractive index change.
Specifically, when step (c) and step (d) are repeated under the same conditions, conical pores 14 as shown in FIG. 3 are formed.
As the number of repetitions in the step (e), the larger the number, the more smoothly tapered pores can be formed, and the total of the step (c) and the step (d) is preferably 3 times or more, more preferably 5 times or more. . When the number of repetitions is 2 or less, the diameter of the pores tends to decrease discontinuously, and when an antireflection article such as an antireflection film is produced from such a stamper, the reflectance reduction effect is insufficient. There is a possibility.

The stamper 20 manufactured in this way has a so-called Moth-Eye structure when the period of the fine concavo-convex structure is less than or equal to the wavelength of visible light, that is, 400 nm or less, and the fine concavo-convex film to which the surface structure of the stamper is transferred is an effective reflection. Preventive function can be expressed.
As shown in FIG. 3, the period is the average of the interval (p in the figure) from the center of the fine pore (concave) 14 of the fine concavo-convex structure to the center of the pore (concave) 14 adjacent thereto.
The period of the pores (recesses) 14 is preferably not more than the wavelength of visible light, that is, not more than 400 nm, more preferably not more than 250 nm, and particularly preferably not more than 200 nm. When the period is larger than 400 nm, visible light is likely to be scattered, and the fine uneven film to which the surface structure of the stamper is transferred tends to make it difficult to exhibit a sufficient antireflection function. The period of the pores (recesses) 14 is preferably 20 nm or more.

Moreover, 80-500 nm is preferable, as for the depth of the pore (recessed part) 14, 100-400 nm is more preferable, and 130-300 nm is especially preferable. If the depth of the pores (recesses) 14 is 80 nm or more, the reflectance of the surface of the fine uneven film to which the surface structure of the stamper is transferred, that is, the transfer surface is lowered. As shown in FIG. 3, the depth of the pores (recesses) 14 is the distance (Dep in the figure) from the opening to the deepest part of the pores (recesses) 14 having a fine concavo-convex structure.
The shape of the pores (recesses) 14 is not limited to the conical shape shown in FIG. 3, and may be, for example, a pyramid shape, a cylindrical shape, an inverted bell shape, or the like. A shape in which the pore cross-sectional area in the direction orthogonal to the vertical direction continuously decreases from the outermost surface in the depth direction is preferable. The shape of the stamper 20 may be a flat plate or a roll.

Further, the surface of the stamper 20 on which the fine concavo-convex structure is formed may be treated with a release agent so as to facilitate release. Examples of the treatment method include a method of coating a silicone resin or a fluorine-containing polymer, a method of depositing a fluorine-containing compound, and a method of coating a fluorine-containing silane compound.
The ink used for masking can be washed away with a solvent or the like.
Although a fine uneven film can be directly produced from the stamper obtained by the above-described production method, a replica may be first produced using the stamper as a prototype, and the fine uneven film may be produced from this replica. Alternatively, a replica may be produced again using this replica as a prototype, and a fine uneven film may be produced from the replica.
As a method for producing a replica, for example, a thin film made of nickel, silver, or the like is formed on a master by electroless plating, sputtering, or the like, and then electroplating (electroforming) is performed using the thin film as an electrode. Examples of the method include a method in which the nickel layer is peeled off from the original mold after being deposited to form a replica.

In the stamper manufacturing method of the present invention described above, the ratio of the area of the smooth portion as shown in FIG. 4 is 10 by anodizing the aluminum substrate after masking the aluminum substrate. A stamper 20 is obtained in which a structure in which a region of greater than 50% and 50% or less and an area of 0.01 mm ² or less is formed on the surface of the aluminum base 10 is obtained. Then, by transferring the concavo-convex structure on the surface of the stamper manufactured by the above-described manufacturing method to the surface of the film, a fine concavo-convex film having antireflection properties, low visibility of scratches, and scratches that are not noticeable can be obtained.

[Production method of fine uneven film]
The manufacturing method of the fine uneven | corrugated film of this invention is a method of transcribe | transferring the surface structure formed in the surface of the above-mentioned stamper to the surface of a molded object main body.
In the fine uneven film manufactured by transferring the surface structure of the stamper, the inverted structure of the surface structure of the stamper is transferred to the surface in a relationship between the key and the keyhole.
As a manufacturing method of a fine uneven | corrugated film, the following method is mentioned, for example.
(1) An active energy ray-curable resin composition is filled between a stamper and a light-transmitting substrate (molded body), and the active energy ray-curable resin composition is in contact with the stamper and the active energy The active energy ray-curable resin composition is irradiated with active energy rays to cure the active energy ray-curable resin composition, and then the stamper is peeled off, and the active energy ray-curable resin composition is formed on the surface of the light-transmitting substrate. A method for obtaining a fine concavo-convex film having a surface structure made of a cured product (that is, forming a cured product in which the surface structure of a stamper is transferred to the surface of a light-transmitting substrate).
(2) The active energy ray-curable resin composition is filled between the stamper and the light-transmitting substrate, the surface structure of the stamper is transferred to the active energy ray-curable resin composition, the stamper is peeled off, The active energy ray-curable resin composition is irradiated with active energy rays to cure the active energy ray-curable resin composition, and the active energy ray-curable resin composition is cured on the surface of the light-transmitting substrate. A method for obtaining a fine concavo-convex film having a surface structure formed thereon (that is, forming a cured product in which the surface structure of a stamper is transferred to the surface of a light-transmitting substrate).

Hereinafter, the method (1) will be described in detail.
The stamper and the light-transmitting substrate are opposed to each other, and the active energy ray-curable resin composition is filled and disposed between them. At this time, the surface on which the stamper surface structure is formed (the surface of the stamper) is made to face the light-transmitting substrate. Next, active energy rays (heat rays such as visible rays, ultraviolet rays, electron beams, plasma, infrared rays) are applied to the filled active energy ray-curable resin composition via a light-transmitting substrate, for example, a high-pressure mercury lamp or a metal halide lamp. To cure the active energy ray-curable resin composition. Thereafter, the stamper is peeled off. As a result, a fine concavo-convex film in which a surface concavo-convex structure made of a cured product of the active energy ray-curable resin composition is formed on the surface of the light transmissive substrate is obtained. At this time, if necessary, the active energy ray may be irradiated again after the stamper is peeled off.
The irradiation amount of an active energy ray should just be the energy amount which hardening progresses, and is 100-10000mJ / cm < ² > normally.

For example, if a manufacturing apparatus as shown in FIG. 5 is used, a fine uneven | corrugated film can be manufactured continuously. An example of the manufacturing method of the fine uneven | corrugated film using the manufacturing apparatus 30 shown in FIG. 5 is demonstrated.
The active energy from the tank 33 is between the surface of the roll-shaped stamper 31 having a fine concavo-convex structure on the surface and the band-like light-transmitting base material (molded body) 32 that moves along the surface of the stamper 31. A linear curable resin composition 34 is supplied.
The transparent base material 32 and the active energy ray curable resin composition 34 are nipped between the stamper 31 and the nip roll 36 whose nip pressure is adjusted by the pneumatic cylinder 35, and the active energy ray curable resin composition 34 is optically irradiated. While spreading uniformly between the permeable base material 32 and the stamper 31, the pores (recesses) of the stamper 31 are also filled.
While the stamper 31 is rotated, an active energy ray irradiation device 37 installed below the stamper 32 in a state where the active energy ray curable resin composition 34 is sandwiched between the stamper 31 and the light transmissive substrate 32. The active energy ray-curable resin composition 34 is irradiated with active energy rays from the light-transmitting substrate 32 side to cure the active energy ray-curable resin composition 34, thereby A cured product 38 having the multi-concave structure of the stamper 31 transferred on the surface is formed.
The fine uneven film 40 is obtained by peeling the transparent substrate 32 having the cured product 38 formed on the surface from the stamper 31 by the peeling roll 39.

The material of the light transmissive substrate (molded body) may be any material that does not significantly inhibit the irradiation of active energy rays. For example, polyethylene terephthalate (PET), methyl methacrylate (co) polymer, polycarbonate, styrene ( Co) polymer, methyl methacrylate-styrene copolymer, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, polyester, polyamide, polyimide, polyether sulfone, polysulfone, polypropylene, polymethylpentene, polyvinyl chloride, polyvinyl acetal , Polyether ketone, polyurethane, cycloolefin polymer, glass, quartz, quartz and the like.
The shape of the light-transmitting transparent substrate can be appropriately selected according to the fine uneven film to be produced. For example, when the use of the fine uneven film is an antireflection article such as an antireflection film, a sheet form or a film form is preferable. . The surface of the light-transmitting substrate is subjected to, for example, various coatings, corona discharge treatment, etc. in order to improve adhesion to the active energy ray-curable resin composition, antistatic properties, scratch resistance, weather resistance, etc. It may be.

(Active energy ray resin composition)
The active energy ray-curable resin composition used in the present invention can contain a polymerizable compound and a polymerization initiator.
Examples of the polymerizable compound include monomers, oligomers, and reactive polymers having a radical polymerizable bond and / or a cationic polymerizable bond in the molecule.
The active energy ray-curable resin composition may contain a non-reactive polymer and an active energy ray sol-gel reactive composition.

Examples of the monomer having a radical polymerizable bond include a monofunctional monomer and a polyfunctional monomer.
Monofunctional monomers include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, s-butyl (meth) acrylate, t- Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, alkyl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, cyclohexyl (meth) acrylate, benzyl (meth) acrylate, Phenoxyethyl (meth) acrylate, isobornyl (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, allyl (meth) acrylate, 2-hydroxyethyl ( )) (Meth) acrylate derivatives such as acrylate, hydroxypropyl (meth) acrylate, 2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate; (meth) acrylic acid, (meth) acrylonitrile; styrene, α -Styrene derivatives such as methylstyrene; (meth) acrylamide derivatives such as (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide and the like. These may be used alone or in combination of two or more.

Polyfunctional monomers include ethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, isocyanuric acid ethylene oxide modified di (meth) acrylate, triethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate , Neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, 1,5-pentanediol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, polybutylene glycol di (Meth) acrylate, 2,2-bis (4- (meth) acryloxypolyethoxyphenyl) propane, 2,2-bis (4- (meth) acryloxyethoxyphenyl) propane, 2,2-bis (4- (3- ( Ta) acryloxy-2-hydroxypropoxy) phenyl) propane, 1,2-bis (3- (meth) acryloxy-2-hydroxypropoxy) ethane, 1,4-bis (3- (meth) acryloxy-2-hydroxypropoxy) ) Butane, dimethylol tricyclodecane di (meth) acrylate, ethylene oxide adduct di (meth) acrylate of bisphenol A, propylene oxide adduct di (meth) acrylate of bisphenol A, neopentyl glycol di (meth) hydroxypivalate Bifunctional monomers such as acrylate, divinylbenzene, and methylenebisacrylamide; pentaerythritol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, trimethylolpropane ethylene oxide Functional tri (meth) acrylate, trimethylolpropane propylene oxide modified triacrylate, trimethylolpropane ethylene oxide modified triacrylate, isocyanuric acid ethylene oxide modified tri (meth) acrylate and other trifunctional monomers; succinic acid / trimethylolethane / acrylic acid 4 or more functional monomers such as dipentaerystol hexa (meth) acrylate, dipentaerystol penta (meth) acrylate, ditrimethylolpropane tetraacrylate, tetramethylolmethanetetra (meth) acrylate; bifunctional or more Urethane acrylates, bifunctional or higher functional polyester acrylates, and the like. These may be used alone or in combination of two or more.
Examples of the monomer having a cationic polymerizable bond include monomers having an epoxy group, an oxetanyl group, an oxazolyl group, a vinyloxy group, and the like, and a monomer having an epoxy group is particularly preferable.

Examples of the oligomer or reactive polymer include unsaturated polyesters such as a condensate of unsaturated dicarboxylic acid and polyhydric alcohol; polyester (meth) acrylate, polyether (meth) acrylate, polyol (meth) acrylate, epoxy (meth) Examples thereof include acrylates, urethane (meth) acrylates, cationic polymerization type epoxy compounds, homopolymers of the above-described monomers having a radical polymerizable bond in the side chain, and copolymerized polymers.
Examples of non-reactive polymers include acrylic resins, styrene resins, polyurethanes, cellulose resins, polyvinyl butyral, polyesters, thermoplastic elastomers, and the like.
Examples of the active energy ray sol-gel reactive composition include alkoxysilane compounds and alkyl silicate compounds.
As an alkoxysilane compound, the compound of following formula (1) is mentioned.
R ¹¹ _x Si (OR ¹² ) _y (1).
^However, R ^{11, R 12} each represent an alkyl group having 1 to 10 carbon atoms, x, y represents an integer satisfying the relation of x + y = 4.

Examples of the alkoxysilane compound include tetramethoxysilane, tetra-i-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-t-butoxysilane, methyltriethoxysilane, Examples include methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, trimethylmethoxysilane, trimethylpropoxysilane, and trimethylbutoxysilane.
Examples of the alkyl silicate compound include a compound of the following formula (2).
R ²¹ O [Si (OR ²³ ) (OR ²⁴ ) O] _z R ²² (2).
^However, R 21 ^{to R 24} each represent an alkyl group having 1 to 5 carbon atoms, z is an integer of 3 to 20. Examples of the alkyl silicate compound include methyl silicate, ethyl silicate, isopropyl silicate, n-propyl silicate, n-butyl silicate, n-pentyl silicate, acetyl silicate and the like.

  When using a photocuring reaction, examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, benzyl, benzophenone, p-methoxybenzophenone, 2,2-diethoxy. Acetophenone, α, α-dimethoxy-α-phenylacetophenone, methylphenylglyoxylate, ethylphenylglyoxylate, 4,4′-bis (dimethylamino) benzophenone, 2-hydroxy-2-methyl-1-phenylpropane- Carbonyl compounds such as 1-one; sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, benzoyl Examples include diethoxyphosphine oxide. These may be used alone or in combination of two or more.

  When using an electron beam curing reaction, examples of the polymerization initiator include benzophenone, 4,4-bis (diethylamino) benzophenone, 2,4,6-trimethylbenzophenone, methyl orthobenzoylbenzoate, 4-phenylbenzophenone, t- Thioxanthone such as butylanthraquinone, 2-ethylanthraquinone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone; diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl Dimethyl ketal, 1-hydroxycyclohexyl-phenyl ketone, 2-methyl-2-morpholino (4-thiomethylphenyl) propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholy Phenyl) -butanone and other acetophenones; benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether and other benzoin ethers; 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2,6-dimethoxybenzoyl)- Acylphosphine oxides such as 2,4,4-trimethylpentylphosphine oxide and bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide; methylbenzoylformate, 1,7-bisacridinylheptane, 9-phenyl Examples include acridine. These may be used alone or in combination of two or more.

When utilizing a thermosetting reaction, examples of the thermal polymerization initiator include methyl ethyl ketone peroxide, benzoyl peroxide, dicumyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, t-butyl peroxy octoate, organic peroxides such as t-butylperoxybenzoate and lauroyl peroxide; azo compounds such as azobisisobutyronitrile; N, N-dimethylaniline, N, N-dimethyl-p- Examples thereof include a redox polymerization initiator combined with an amine such as toluidine.
The active energy ray-curable resin composition may contain an antistatic agent, a release agent, an additive such as a fluorine compound for improving the antifouling property, fine particles, and a small amount of a solvent, if necessary.

[Articles with fine uneven film]
The article provided with the fine uneven film of the present invention includes, for example, an image display device such as a touch panel, a liquid crystal display device, a plasma display panel, an electroluminescence display, and a cathode tube display device, a lens, a show window, a spectacle lens, 1/2 Affixed to the surface of an object such as a wave plate or a low-pass filter.
When the article has a three-dimensional shape, a transparent article having a shape corresponding to the application can be manufactured in advance and used as a member constituting the surface of the object.
When the object is an image display device, not only the surface thereof, but also a fine uneven film may be attached to the front plate, or the front plate itself can be composed of a fine uneven film. .
Other uses of the fine concavo-convex film include optical uses (optical waveguides, relief holograms, lenses, polarized light separation elements, crystal devices, etc.), cell culture sheets, super water-repellent films, super hydrophilic films, and the like. The super water-repellent film can be used by being attached to windows of automobiles, railway vehicles, etc., and can be used for preventing snow accretion and icing for headlamps, lighting and the like.

Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.
<Various measurements and evaluation methods>
(Stamper pores, smooth surface dimensions)
Platinum was deposited on the longitudinal section or surface of the stamper for 1 minute, and the surface of the stamper was observed using a scanning electron microscope (“JSM-7400F” manufactured by JEOL Ltd.) under an acceleration voltage of 3.00 kV. From the obtained image, the period of the fine pores (concave portions) of the fine concavo-convex structure made of anodized alumina, the depth of the pores, and the dimension of the smooth surface were measured at 10 locations, and the average value was obtained.
(Convex part of fine uneven film, dimensions of smooth surface)
Platinum is vapor-deposited for 5 minutes on the longitudinal section or surface of the fine uneven film on which the transfer surface is formed, and is fine under the condition of acceleration voltage: 3.00 kV using a scanning electron microscope (“JSM-7400F” manufactured by JEOL Ltd.). The transfer surface of the uneven film was observed. From the obtained image, the period of the convex part derived from the fine concavo-convex structure of the stamper formed on the transfer surface, the height of the convex part, and the dimension of the smooth part were measured at ten points, and the average value was obtained.

(Evaluation of antireflection (reflectance))
A spectrophotometer ("U-4100", manufactured by Hitachi, Ltd.) was prepared by attaching an acrylic adhesive to the back of the fine uneven film (the surface on which the stamper's surface structure was not transferred) and attaching it to a black acrylic plate. Was used to measure the relative reflectance of the surface of the fine concavo-convex film (transfer surface onto which the surface structure of the stamper was transferred) at an incident angle of 5 ° and a wavelength of 380 nm to 780 nm.

(Evaluation of scratch resistance)
The surface of the fine concavo-convex film was strongly rubbed 10 times with gauze to bring the gauze and the surface of the fine concavo-convex film into strong contact. The samples before and after the test were compared with each other by shining light in a dark room and confirmed from the front, and it was confirmed whether there was a change in appearance due to scratches. A case where no change was observed was evaluated as ◯, and a case where a change was observed was evaluated as x.

(Evaluation of quality)
The fine concavo-convex film was visually confirmed by illuminating light in a dark room from the front, and the smooth portion was visually confirmed to confirm that there was no adverse effect on the quality. The case where the smooth part could not be confirmed and there was no problem in the quality was evaluated as ○, and the case where the smooth part could be confirmed and there was a problem in the quality was evaluated as ×.

[Example 1]
<Manufacture of stampers>
A region in which an ink is uniformly dispersed at a rate of 15% with respect to the entire area of the base material using an inkjet apparatus on an aluminum base material having a purity of 99.3% by mass, and the area per one is 0.0025 mm ² Was processed to be masked.
Next, the masked aluminum substrate was anodized in a 0.3 M oxalic acid aqueous solution under conditions of bath temperature: 16 ° C. and direct current: 40 V to form an oxide film (step (a)). . The formed oxide film was once dissolved and removed in a 6% by mass phosphoric acid and 1.8% by mass chromic acid mixed aqueous solution (step (b)), and then again under the same conditions as in step (a). Anodized for 2 seconds to form an oxide film (step (c)). Thereafter, the substrate was immersed in a 5% by mass phosphoric acid aqueous solution (30 ° C.) for 8 minutes, and subjected to a pore diameter expansion treatment (step (d)) for expanding the pores of the oxide film. Further, the step (c) and the step (d) were repeated, and these were performed a total of 5 times (step (e)) to form anodized alumina on the aluminum base material. Next, the masking ink is removed with acetone, immersed in a 0.1% by weight diluted solution of OPTOOL DSX (manufactured by Daikin Industries) for 10 minutes, air-dried for 24 hours, and the surface of the anodized alumina is removed with a release agent. The stamper was obtained by processing.
In addition, when the surface of the obtained stamper was observed with a scanning electron microscope, as shown in FIG. 3, fine irregularities composed of conical tapered pores (concave portions) having a period p: 100 nm and a depth D _ep : 210 nm. Structure 16 was formed on the surface. Further, the smooth portion 17 having a fine area of 0.0025 mm ² per area and having no fine irregularities was formed at a rate of 20% with respect to the entire area of the stamper surface.

<Preparation of active energy ray-curable resin composition>
45 parts by weight of a condensation reaction mixture of succinic acid / trimethylolethane / acrylic acid molar ratio 1: 2: 4,
45 parts by mass of 6-hexanediol diacrylate (manufactured by Osaka Organic Chemical Industry),
10 parts by mass of radical polymerizable silicone oil (manufactured by Shin-Etsu Chemical Co., Ltd., “X-22-1602”),
3 parts by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, “Irgacure 184”),
0.2 parts by mass of bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide (manufactured by BASF, “Irgacure 819”),
Were mixed to obtain an active energy ray-curable resin composition.

<Manufacture of fine uneven film>
A few drops of the active energy ray-curable resin composition is dropped on the surface of the stamper, and a polyethylene terephthalate film (A-4300, manufactured by Toyobo Co., Ltd.) having a thickness of 188 μm is formed thereon as a molded body (light-transmitting substrate). ) Was spread while being spread, and then the active energy ray-curable resin composition was photocured by irradiating ultraviolet rays with an energy of 1600 mJ / cm ² from the film side. Thereafter, the film and the stamper were peeled off to obtain a fine uneven film.
On the surface (transfer surface) of the obtained fine uneven film, the surface structure of the stamper was transferred. Note that convex portions having a period P ′: 100 nm and a height H: 190 nm as shown in FIG. 1 were formed on the transfer surface. Further, the smooth portion without fine unevenness is at a ratio of 15% with respect to the entire area of the surface (transfer surface) of the fine uneven film at a position equivalent to the valley bottom of the portion having the fine uneven structure, and The area per one was formed with a size of 0.0025 mm ² .
The obtained fine uneven film was evaluated for antireflection properties, scratch resistance, and quality. The results are shown in Table 1.

[Example 2]
A stamper was manufactured in the same manner as in Example 1 except that the masked area was 40% of the entire stamper area. Using the obtained stamper, a fine uneven film was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[Example 3]
A stamper was manufactured in the same manner as in Example 1 except that the area per masking was set to 0.081 mm ² . Using the obtained stamper, a fine uneven film was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[Comparative Example 1]
A stamper was manufactured in the same manner as in Example 1 except that the masked area was set to 5% of the entire stamper area. Using the obtained stamper, a fine uneven film was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[Comparative Example 2]
A stamper was manufactured in the same manner as in Example 1 except that the masked area was 60% of the entire stamper area. Using the obtained stamper, a fine uneven film was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[Comparative Example 3]
A stamper was manufactured in the same manner as in Example 1 except that the area per masking was set to 0.03 mm ² . Using the obtained stamper, a fine uneven film was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.
[Comparative Example 4]
A stamper was manufactured in the same manner as in Example 1 except that processing was performed without performing masking. Using the obtained stamper, a fine uneven film was produced and evaluated in the same manner as in Example 1. The results are shown in Table 1.

As is clear from Table 1, the fine uneven films obtained in Examples 1 to 3 were excellent in antireflection properties, scratch resistance and quality.
On the other hand, the fine concavo-convex film obtained in Comparative Example 1 had inferior scratch resistance because the area of the smooth portion was as small as 5%.
The fine concavo-convex film obtained in Comparative Example 2 was inferior in antireflection performance because the area of the smooth part was as large as 60%, and the smooth part could be visually confirmed, and there was a problem in quality.
Since the fine concavo-convex film obtained in Comparative Example 3 had a large area per smooth part of 0.03 mm ² , the smooth surface could be visually confirmed and there was a problem in quality.
The fine concavo-convex film obtained in Comparative Example 4 was not masked before anodic oxidation, so there was no smooth portion, and although the antireflection performance was good, the scratch resistance performance was poor.

DESCRIPTION OF SYMBOLS 1 Part which has fine concavo-convex structure 2 Smooth part 10 Aluminum base material 11, 14 Pore (concave part)
12, 15 Oxide film 13 Pore generation point 16 Part having fine uneven structure (stamper)
17 Smooth part (stamper)
20, 30 Stamper 32 Light transmissive substrate (molded body)
38 Cured product 40 Fine uneven film 41 Convex part 42 Concave part

Claims (6)

  A fine concavo-convex film having a portion having a fine concavo-convex structure on the surface and a plurality of smooth portions, wherein the ratio of the area of the smooth portion to the total surface area is greater than 10% and 50% or less.   2. The fine uneven film according to claim 1, wherein the height of the smooth portion is at a height equivalent to a valley bottom of the portion having the fine uneven structure. The fine uneven film according to claim 1, wherein an area per one of the smooth portions is 0.01 mm ² or less.   The fine concavo-convex film according to claim 1, wherein the fine concavo-convex structure includes a plurality of convex portions having an average height of 80 to 500 nm and a period of 20 to 400 nm.   An article comprising the fine uneven film according to claim 1.   A stamper having a portion having a fine concavo-convex structure on the surface and a plurality of smooth portions, the ratio of the area of the smooth portion to the total surface area being greater than 10% and 50% or less is opposed to the light-transmitting substrate. The active energy ray-curable resin composition is filled between them, and then the active energy ray-curable resin composition filled is irradiated with active energy rays via a light-transmitting substrate to activate the active energy ray-curable resin composition. The manufacturing method of the fine uneven | corrugated film of Claim 1 to 4 which peels a stamper after hardening | curing an energy-beam curable resin composition.