JP6900688B2 - A method for manufacturing a mold with a protective film and an article having an uneven structure - Google Patents

Description

The present invention relates to a mold with a protective film and a method for manufacturing an article having an uneven structure.

Articles having a concavo-convex structure such as a prism sheet and a moth-eye film are generally manufactured by transferring from a mold having an inverted structure of the concavo-convex structure. From the time after the production of the mold having the inverted structure of the uneven structure to the start of the production of the article having the uneven structure, the process of transporting and storing the mold is performed. During these steps, a protective film is often applied to the surface of the mold for the purpose of preventing the application of foreign matter such as dust and dirt on the surface of the mold and the prevention of scratches on the surface of the mold.

In particular, since moth-eye film may impair the original performance of antireflection performance based on foreign matter and scratches on the surface of the mold, more advanced prevention of foreign matter and scratches is required on the surface of the mold. Has been done.

As a method for protecting a mold, for example, Patent Document 1 discloses a method using a protective sheet in which a polypropylene sheet and an aluminum foil are laminated.

Japanese Unexamined Patent Publication No. 2010-228347

However, the protection method using the protective sheet disclosed in Patent Document 1 has a problem that foreign matter generated during the manufacture of the mold remains as it is until the manufacture of the article having the uneven structure.

In addition, the general method of protecting with an adhesive film, in which the adhesive adheres to the adherend by adapting to the adherend, can remove foreign substances generated during the manufacture of a mold having an inverted structure having an uneven structure when the adhesive film is peeled off. When the adhesive film is applied for a long period of time, the adhesive strength changes depending on the storage conditions such as location, period, temperature, and load, and there is a problem that the adhesive remains on the surface of the mold.

Therefore, the present invention is to solve these problems and provide a mold having an inverted structure having a concavo-convex structure that suppresses foreign matter adhering to the surface. Another object of the present invention is to provide an article having an uneven structure in which surface defects are suppressed.

The present invention has the following aspects.
[1] A mold with a protective film including a mold and a protective film applied to the surface of the mold, wherein the mold is a mold for forming an uneven structure by transfer.
Protective film, I self-adhesive film der which the adhesive force increases with an increase in temperature,
A mold with a protective film in which the adhesive strength of the self-adhesive film to the acrylic plate at 23 ° C. is 0.3 N / 25 mm or less.
[2] The mold with a protective film according to [1], wherein the uneven structure is a moth-eye structure.
[3] The mold with a protective film according to [1] or [2], wherein the mold is in a roll shape.
[4] The mold with a protective film according to any one of [1] to [3] , wherein the self-adhesive film has an adhesive force of 0.4 N / 25 mm or more on an acrylic plate at 75 ° C.
[ 5 ] The mold with a protective film according to any one of [1] to [4 ], wherein the pressure-sensitive adhesive of the self-adhesive film is an elastomer.
[6] The method for manufacturing a mold with a protective film according to any one of [1] to [5], which comprises the following step A.
Step A: A step of applying the self-adhesive film as a protective film to the surface of a mold for forming an uneven structure by transfer in an environment of 0 ° C. to 40 ° C.
[7] A method for producing an article having a concavo-convex structure, which comprises the following steps B to C in sequence.
Step B: A step of raising the temperature of the mold obtained by the manufacturing method described in [6] to 50 ° C. to 90 ° C. and peeling the protective film from the mold.
Step C: A step of supplying the active energy ray-curable composition to the surface of the mold and curing the active energy ray-curable composition.
[8] The method for producing an article having a concavo-convex structure according to [7], wherein the concavo-convex structure is a moth-eye structure.
[9] The method for producing an article having a concavo-convex structure according to [7] or [8], wherein the mold is in a roll shape.
[10] The method for producing an article having an uneven structure according to any one of [7] to [9], wherein the pressure-sensitive adhesive of the self-adhesive film is an elastomer.
[11] The method for producing an article having an uneven structure according to any one of [7] to [10], wherein the article having an uneven structure is an antireflection film.

The mold with a protective film of the present invention can suppress foreign matter adhering to the surface of a mold having an inverted structure having an uneven structure after the protective film is peeled off.
In addition, the method for producing an article having an uneven structure of the present invention can suppress surface defects of the obtained article having an uneven structure.

It is a schematic cross-sectional view which shows an example of the method of applying a protective film to the surface of a mold. It is a schematic cross-sectional view which shows an example of the manufacturing apparatus used in the manufacturing method of the article which has an uneven structure. It is a graph which shows the adhesive force of the protective film used in Example and comparative example with respect to an acrylic plate at 23 degreeC to 75 degreeC.

(Mold with protective film)
The mold with a protective film of the present invention includes a mold and a protective film applied to the surface of the mold.

(Mold)
The mold is not particularly limited as long as it is a mold for forming a concavo-convex structure by transfer.
Examples of the mold include a mold for a prism sheet, a mold for a microlens sheet, a mold for a moth-eye film, and the like. Among these molds, the mold for moth-eye film is preferable because the effect of suppressing foreign substances, which is the effect of the present invention, is more required.

Examples of the shape of the mold include a roll shape, a belt shape, a flat plate shape, and the like. Among these mold shapes, a roll shape and a belt shape are preferable, and a roll shape is more preferable, because the product having an uneven structure is excellent in productivity.

Examples of the mold manufacturing method include a method of providing an inverted structure of an uneven structure on the surface by a lithography method, a method of providing an inverted structure of an uneven structure on the surface by laser processing, and a method of providing anodized porous alumina having a plurality of pores on the surface. Examples thereof include a method of forming the shavings and a method of duplicating from a mother die having an uneven structure by an electroplating method or the like. Among these mold manufacturing methods, since the productivity of articles having a concavo-convex structure is excellent, a method of providing an inverted structure of the concavo-convex structure on the surface by laser processing and anodized porous alumina having a plurality of pores are applied to the surface. Since the method of forming is preferable and the productivity of the moth-eye film which more requires the effect of suppressing foreign substances, which is the effect of the present invention, is excellent, the method of forming anodized porous alumina having a plurality of pores on the surface is more preferable. preferable.

Examples of the lithography method include an electron beam lithography method and a laser interference lithography method.
As a method of providing an inverted structure of an uneven structure on the surface by a lithography method, for example, a photoresist film is applied to the surface of a base material, exposed to an ultraviolet laser, an electron beam, an X-ray, or the like, and developed to obtain a resist pattern. A method of forming a concavo-convex structure composed of the above on the surface, a method of selectively etching a base material through the resist pattern by dry etching or the like, removing the resist pattern, and directly forming the concavo-convex structure on the surface of the base material, etc. Can be mentioned.

Examples of the method of forming anodized porous alumina having a plurality of pores on the surface include a method of anodizing aluminum at a predetermined voltage using oxalic acid, sulfuric acid, phosphoric acid or the like as an electrolytic solution.
According to the method of anodizing aluminum at a predetermined voltage using oxalic acid, sulfuric acid, phosphoric acid, etc. as an electrolytic solution, high-purity aluminum is anodized at a constant voltage for a long time, and then all or part of the oxide film is once. By removing and re-anodizing, it is possible to form anodized porous alumina in which very highly regular pores are self-assembled, which is preferable. Further, by combining the anodizing treatment and the pore diameter expanding treatment in the second anodizing step, it is possible to form pores having a triangular or bell-shaped cross section instead of a rectangular cross section. Further, the angle of the innermost part of the pores can be sharpened by appropriately adjusting the time, number of times, conditions and the like of the anodizing treatment and the pore diameter expanding treatment.
Specific examples of the method for forming anodized porous alumina having a plurality of pores on the surface include the methods described in JP-A-2015-129706.

(Protective film)
The protective film is a self-adhesive film whose adhesive strength increases as the temperature rises. Specifically, the adhesive strength of the self-adhesive film to the acrylic plate at 23 ° C. is 0.3 N / 25 mm or less, and the adhesive strength of the self-adhesive film to the acrylic plate at 75 ° C. is 0.4 N / 25 mm or more. It is a self-adhesive film.

The adhesive strength of the self-adhesive film to the acrylic plate at 23 ° C. is preferably 0.3 N / 25 mm or less, more preferably 0.01 N / 25 mm to 0.3 N / 25 mm, and 0.05 N / 25 mm to 0.25 N / 25 mm or less. Is more preferable. When the adhesive strength of the self-adhesive film to the acrylic plate at 23 ° C. is 0.01 N / 25 mm or more, the adhesiveness between the mold and the protective film is excellent. Further, when the adhesive force of the self-adhesive film to the acrylic plate at 23 ° C. is 0.3 N / 25 mm or less, the residual adhesive on the surface of the mold can be suppressed even if the adhesive film is applied for a long period of time. ..

The adhesive force of the self-adhesive film to the acrylic plate at 75 ° C. is preferably 0.4 N / 25 mm or more, more preferably 0.4 N / 25 mm to 2 N / 25 mm, and further preferably 0.5 N / 25 mm to 1 N / 25 mm or less. When the adhesive force of the self-adhesive film to the acrylic plate at 75 ° C. is 0.4 N / 25 mm or more, foreign matter generated during the production of a mold having an inverted structure having an uneven structure can be removed when the adhesive film is peeled off. Further, when the adhesive force of the self-adhesive film to the acrylic plate at 75 ° C. is 2N / 25 mm or less, the residual adhesive on the surface of the mold can be suppressed.

The adhesive strength of the self-adhesive film is preferably 0.4 N / 25 mm or more at each temperature of 50 ° C. to 90 ° C. The adhesive strength of the self-adhesive film to the acrylic plate at each temperature of 50 ° C. to 90 ° C. is preferably 0.4 N / 25 mm or more, more preferably 0.4 N / 25 mm to 2 N / 25 mm, and 0.5 N / 25 mm to 1 N /. 25 mm or less is more preferable. When the adhesive force of the self-adhesive film to the acrylic plate at each temperature of 50 ° C. to 90 ° C. is 0.4 N / 25 mm or more, foreign matter generated during the manufacture of a mold having an inverted structure of an uneven structure is removed when the adhesive film is peeled off. can do. Further, when the adhesive force of the self-adhesive film to the acrylic plate at each temperature of 50 ° C. to 90 ° C. is 2N / 25 mm or less, the residual adhesive on the surface of the mold can be suppressed.

The adhesive of the self-adhesive film has an adhesive force of the self-adhesive film on the acrylic plate at 23 ° C. of 0.3 N / 25 mm or less, and an adhesive force of the self-adhesive film on the acrylic plate at 75 ° C. of 0.4 N / 25 mm. The above is not particularly limited, but the adhesive strength of the self-adhesive film to the acrylic plate at 23 ° C. is 0.3 N / 25 mm or less, and the adhesive strength of the self-adhesive film to the acrylic plate at 75 ° C. is 0.4 N / 25 mm. Elastomers are preferred because they achieve the above.

The self-adhesive film should have an adhesive force of the self-adhesive film to the acrylic plate at 23 ° C. of 0.3 N / 25 mm or less and an adhesive force of the self-adhesive film to the acrylic plate at 75 ° C. of 0.4 N / 25 mm or more. For example, a commercially available self-adhesive film may be used. Specifically, for example, "FSA-010M", "FSA-020M", "FSA-010C", "FSA-010B", "FSA-020B" (trade name) manufactured by Futamura Chemical Co., Ltd. are mentioned. Be done.

(Manufacturing method of articles having an uneven structure)
The method for producing an article having a concavo-convex structure of the present invention sequentially includes the following steps A to C.
Step A: The surface of the mold for forming an uneven structure by transfer in an environment of 0 ° C to 40 ° C.
In addition, as a protective film, a self-adhesive fill whose adhesive strength increases as the temperature rises.
The process of giving
Step B: The temperature of the mold is raised to 50 ° C. to 90 ° C., and the protective film is peeled off.
Process.
Step C: The active energy ray-curable composition is supplied to the surface of the mold, and the active energy is used.
A step of curing a ghee wire curable composition.

(Step A)
Step A is a step of applying a self-adhesive film as a protective film, whose adhesive strength increases as the temperature rises, to the surface of a mold for forming an uneven structure by transfer in an environment of 0 ° C. to 40 ° C.
Since the step A can suppress foreign matter adhering to the surface of the mold, it is preferable to perform the step A immediately after the production of the mold having the inverted structure of the uneven structure.

The environment in which the protective film is applied is preferably a temperature at which self-adhesiveness of the self-adhesive film does not occur, preferably 0 ° C to 40 ° C, and more preferably 5 ° C to 35 ° C.

The method of applying the protective film to the surface of the mold is preferable because it can protect the mold and the protective film can be easily peeled off. Hereinafter, a method of applying the protective film to the surface of the mold will be described with reference to FIG. 1, but the method of applying the protective film to the surface of the mold is not limited to FIG.

In the method of applying the protective film to the surface of the mold shown in FIG. 1, the protective film 13 is wound from the upstream side in the rotational direction to the downstream side in the rotational direction of the roll-shaped mold 11, and the rear end 13a of the protective film is wound. Is arranged so as to come into contact with the protective film 13, and the tip 13b of the protective film is arranged so as to overlap a part of the protective film 23 and come into contact with the outer peripheral surface of the protective film 23.

The length of the protective film is preferably longer than the outer peripheral length of the roll-shaped mold because it can protect the mold and the protective film can be easily peeled off. .5 times or more is preferable.

The tip of the protective film does not necessarily have to be adhered to the outer peripheral surface of the protective film, and it is sufficient that the tip of the protective film is held to such an extent that it does not unintentionally come off from the roll-shaped mold.

(Step B)
Step B is a step of raising the temperature of the mold to 50 ° C. to 90 ° C. and peeling off the protective film.
Since the step B can suppress foreign matter adhering to the surface of the mold, it is preferable to perform the step B immediately before the production of the article having the uneven structure (step C).

The environment for peeling the protective film is preferably a temperature at which self-adhesiveness of the self-adhesive film occurs, preferably 50 ° C. to 90 ° C., and more preferably 55 ° C. to 85 ° C.

(Step C)
Step C is a step of supplying the active energy ray-curable composition to the surface of the mold and curing the active energy ray-curable composition.
The method of supplying the active energy ray-curable composition to the surface of the mold and curing the active energy ray-curable composition is excellent in transferability of the concavo-convex structure and productivity of the article having the concavo-convex structure. After curing the active energy ray-curable composition with the active energy ray-curable composition sandwiched between the mold having the inverted structure of the above and the base material, the cured product and the mold are separated. The method is preferred.

The active energy ray-curable composition is a composition in which a polymerization reaction proceeds by irradiating with active energy rays and the composition is cured.
Examples of the active energy ray include visible light, ultraviolet light, electron beam, plasma, heat ray (infrared ray, etc.) and the like. Among these active energy rays, ultraviolet rays and electron beams are preferable, and ultraviolet rays are more preferable, because the active energy ray-curable composition is excellent in curability.

The active energy ray-curable composition preferably contains a polymerizable compound, a polymerization initiator, and, if necessary, other additives.

Examples of the polymerizable compound include monomers, oligomers, and reactive polymers containing at least one of a radically polymerizable bond and a cationically polymerizable bond in the molecule. These polymerizable compounds may be used alone or in combination of two or more.

Examples of the monomer having a radically polymerizable bond include a monofunctional monomer having a (meth) acryloyl group, a vinyl group and the like, a polyfunctional monomer having a (meth) acryloyl group, a vinyl group and the like. As these monomers having a radically polymerizable bond, one type may be used alone, or two or more types may be used in combination.
As used herein, (meth) acrylic refers to acrylic, methacryl, or both.

Examples of the monomer having a cationically polymerizable bond include a monomer having an epoxy group, an oxetanyl group, an oxazolyl group, a vinyloxy group and the like. As these monomers having a cationically polymerizable bond, one type may be used alone, or two or more types may be used in combination.

Examples of the oligomer or reactive polymer containing at least one of radically polymerizable bonds and cationically polymerizable bonds in the molecule include unsaturated polyester compounds such as a condensate of unsaturated dicarboxylic acid and polyhydric alcohol; polyester (meth). ) Acrylic; Polyester (meth) acrylate; Polyester (meth) acrylate; Epoxy (meth) acrylate; Urethane (meth) acrylate; Cationic polymerization type epoxy compound; Monomer having the radically polymerizable bond in the side chain alone or copolymerization Examples include polymers. As the oligomer or reactive polymer containing at least one of a radical polymerizable bond and a cationically polymerizable bond in these molecules, one type may be used alone, or two or more types may be used in combination.

Examples of the polymerization initiator include known photopolymerization initiators, known electron beam polymerization initiators, known thermal polymerization initiators, and the like. These polymerization initiators may be used alone or in combination of two or more.

Other additives include, for example, non-reactive polymers, antioxidants, mold release agents, lubricants, plasticizers, antioxidants, light stabilizers, flame retardants, flame retardants, polymerization inhibitors, UV absorbers. Examples thereof include agents, fillers, silane coupling agents, reinforcing agents, inorganic fillers, impact resistance modifiers and the like. These other additives may be used alone or in combination of two or more.

When water repellency is imparted to the surface of the concavo-convex structure (specifically, the contact angle between the concavo-convex structure and water is 90 ° or more), as an active energy ray-curable composition capable of forming a hydrophobic material, It is preferable to use a fluorine-containing compound or a silicone-based compound.

When hydrophilicity is imparted to the surface of the concavo-convex structure (specifically, the contact angle between the concavo-convex structure and water is 25 ° or less), as an active energy ray-curable composition capable of forming a hydrophilic material, It is preferable to use a tetrafunctional or higher polyfunctional (meth) acrylate and a bifunctional or higher hydrophilic (meth) acrylate in combination.

Specific examples of the composition of the active energy ray-curable composition include the compositions described in JP2013-175733A and JP2015-129497A.

As a method of sandwiching the active energy ray-curable composition between the mold and the base material, for example, the mold and the base have the active energy ray-curable composition arranged between the mold and the base material. Examples thereof include a method of injecting the active energy ray-curable composition into the uneven structure of the mold by pressing the material.

(Base material)
Examples of the material of the base material include acrylic resin such as polymethylmethacrylate; polycarbonate resin; styrene resin such as polystyrene and methylmethacrylate-styrene copolymer; cellulose resin such as cellulose diacetate, cellulose triacetate and cellulose acetate butyrate; Polyester resin such as polyethylene terephthalate; polyamide resin; polyimide resin; polyether sulfone resin; polysulfone resin; polyolefin resin such as polypropylene, polymethylpentene, alicyclic polyolefin; vinyl chloride resin such as polyvinyl chloride; polyvinyl acetal resin; Polyether ketone resin; polyurethane resin; glass and the like can be mentioned. Among these base material materials, acrylic resin, polycarbonate resin, polyester resin, and cellulose resin are preferable, and polyester resin and cellulose resin are more preferable, because they are excellent in light transmission and handleability.

Examples of the form of the base material include known forms such as films and sheets. Among these forms of the base material, films and sheets are preferable because they are excellent in productivity and handleability of articles having an uneven structure.

Examples of the method for producing the base material include known production methods such as an injection molding method, an extrusion molding method, and a cast molding method. Among these methods for producing a base material, an extrusion molding method and a cast molding method are preferable because they are excellent in productivity.

The surface of the base material may be coated, corona-treated, or the like for the purpose of improving properties such as adhesion, antistatic property, scratch resistance, and weather resistance.

The difference in refractive index between the cured product of the active energy ray-curable composition and the substrate can suppress the reflection of light at the interface between the layer of the cured product of the active energy ray-curable composition and the substrate, and the reflection can be suppressed. Since it is excellent in optical performance such as prevention performance, it is preferably 0.3 or less, and more preferably 0.1 or less.

(Process B / Process C)
In steps B and C, the protective film can be easily peeled off, foreign matter adhering to the surface of the mold after the protective film is peeled off can be suppressed without leaving an adhesive on the surface of the mold, and the mold has an uneven structure. It is preferable to use the manufacturing apparatus shown in FIG. 2 because the productivity of the article is excellent and surface defects of the article having an uneven structure can be suppressed. Hereinafter, the process B and the process C will be specifically described using the manufacturing apparatus shown in FIG. 2, but the process B and the process C are not limited to the method using the manufacturing apparatus shown in FIG.

The flow of the process B and the process C using the manufacturing apparatus shown in FIG. 2 is as follows.
A roll-shaped mold 11 having a protective film 13 on its surface is attached to a manufacturing apparatus, and the temperature of the mold is raised within the range of 50 ° C. to 90 ° C. to increase the adhesive strength of the protective film 13 which is a self-adhesive film. The base material 29 is bridged over the nip roll 25, the roll-shaped mold 11, and the peeling roller 27. Since the protective film 13 is attached to the roll-shaped mold 11 when the base material 29 is bridged, scratches on the surface of the mold 11 due to rubbing or the like are prevented.
Next, the nip roll 25 and the peeling roller 27 are brought close to the roll-shaped mold 11, and the base material 29 is pressed against the roll-shaped mold 11. Here, if the adhesive force between the protective film 13 and the base material 29 is greater than the adhesive force between the protective film 13 and the roll-shaped mold 11, the tip 13b of the protective film is folded back and the protective film 13 at the tip 13b of the protective film is folded back. The protective film 23 is attached to the base material 29 by the adhesive force of the above, and the protective film 23 is peeled off from the roll-shaped mold 11 while running the base material 29. If the adhesive strength between the protective film 13 and the base material 29 is smaller than the adhesive strength between the protective film 13 and the roll-shaped mold 11, the tip 13b of the protective film and the base material 29 are attached with adhesive tape or the like, and the base material is attached. While running 29, the protective film 23 is peeled off from the roll-shaped mold 11.
Next, the active energy ray-curable composition is supplied from the tank 21 between the roll-shaped mold 11 and the base material 29, pressed by the nip roll 25, and the base material 29 is run while being driven by the active energy ray irradiation device 23. The active energy ray-curable composition is cured by irradiating with active energy rays to obtain an article having an uneven structure.

The base material may be continuously run between the steps B and C, or the running of the base material may be temporarily stopped.

(Concave and convex structure)
The uneven structure is composed of a plurality of convex portions and a concave portion formed between the plurality of convex portions.
The average spacing (pitch) between adjacent convex portions of the concavo-convex structure is not particularly limited, but when the article having the concavo-convex structure is a moth-eye film, it is excellent in antireflection performance, so that it is below the wavelength of visible light, that is, 400 nm or less. Is preferable, and 380 nm or less is more preferable.

When the article having the concavo-convex structure is a moth-eye film, the average spacing between adjacent convex portions of the concavo-convex structure is preferably 20 nm to 300 nm, more preferably 80 nm to 200 nm. When the average distance between adjacent convex portions of the concave-convex structure is 20 nm or more, the convex portions are likely to be formed when a plurality of pores of the anodized porous alumina are transferred to form the convex portions. Further, when the average spacing between adjacent convex portions of the concave-convex structure is 300 nm or less, a voltage for increasing the pore spacing when transferring a plurality of pores of anodized porous alumina to form convex portions. It is possible to suppress the above, and it is easy to industrially produce anodized porous alumina.

In the present specification, the average spacing between adjacent convex portions is the interval between adjacent convex portions (distance from the center of the convex portion to the center of the adjacent convex portion) at random 10 using electron microscope observation. Point measurement is performed and these values are averaged.

When the article having the uneven structure is a moth-eye film, the average height of the convex portion is preferably 60 nm to 400 nm, more preferably 90 nm to 350 nm. When the average height of the convex portion is 60 nm or more, it is possible to suppress an increase in the minimum reflectance and the reflectance at a specific wavelength, and the antireflection performance is excellent. Further, when the average height of the convex portion is 400 nm or less, the convex portion is easily formed and the convex portion is excellent in scratch resistance.

In the present specification, the average height of the convex portion is obtained by randomly measuring the vertical distance between the top of the convex portion and the bottom of the adjacent concave portion at 10 points using electron microscope observation. Is the average value.

When the article having the uneven structure is a moth-eye film, the aspect ratio of the convex portions (average height of the convex portions / average spacing between adjacent convex portions) is preferably 0.8 to 5.0, and 1.2 to 4 .0 is more preferable, and 1.5 to 3.0 is even more preferable. When the aspect ratio of the convex portion is 0.8 or more, the antireflection performance is excellent. Further, when the aspect ratio of the convex portion is 5.0 or less, the convex portion is easily formed and the convex portion is excellent in scratch resistance.

When the article having the uneven structure is a moth-eye film, examples of the shape of the convex portion include a conical shape, a pyramid shape, a bell shape, a cylindrical shape, and the like. As for the shape of these convex portions, one type may be used alone, or two or more types may be used in combination. Among these convex shapes, it is possible to continuously increase the refractive index from the air to the surface of the material forming the concave-convex structure to exhibit antireflection performance that achieves both low reflectance and low wavelength dependence. Therefore, a shape in which the cross-sectional area of the convex portion in the direction orthogonal to the height direction continuously increases from the top in the depth direction is preferable, and a conical shape, a pyramid shape, and a bell shape are more preferable.
The convex portion may be one in which a plurality of fine convex portions are united to form one convex portion.

The obtained article having an uneven structure can be suitably used for a prism sheet, a microlens sheet, and a moth-eye film, and is particularly preferably used for a moth-eye film which more requires the effect of suppressing foreign substances, which is the effect of the present invention. be able to.
The moth-eye film can be suitably used as an antireflection film.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.

(Measurement of adhesive strength of protective film against acrylic plate)
For the protective film used in Examples and Comparative Examples, a peeling tester (model name "IPT-200-50N", manufactured by Imada Co., Ltd.) was used, and the peeling speed was 300 mm / min at 23 ° C to 75 ° C. The adhesive strength of the protective film to the acrylic plate (trade name "Acrylite L001", manufactured by Mitsubishi Rayon Co., Ltd.) was measured.
The evaluation results are shown in Table 1 and FIG.

[Production Example 1] Manufacture of a mold An aluminum ingot with a purity of 99.99% is cut into an outer diameter of 200 mm, an inner diameter of 155 mm, and a length of 350 mm, and a cylindrical aluminum base material having no rolling marks is subjected to a feather cloth polishing treatment. After that, electropolishing was performed in a mixed solution of perchloric acid / ethanol (volume ratio = 1/4) to make a mirror surface.
The obtained aluminum base material was anodized in a 0.3 M aqueous oxalic acid solution under the conditions of a direct current of 40 V and a temperature of 16 ° C. for 10 minutes. Then, the aluminum base material was immersed in a 6 mass% phosphoric acid / 1.8 mass% chromic acid mixed aqueous solution to remove the oxide film.
The obtained aluminum base material was anodized in a 0.3 M aqueous oxalic acid solution under the conditions of a direct current of 40 V and a temperature of 16 ° C. for 30 seconds.
The obtained aluminum base material on which the oxide film was formed was immersed in a 5% by mass phosphoric acid aqueous solution at 30 ° C. for 8 minutes to perform a pore size enlargement treatment (pore size enlargement treatment step). Then, the aluminum base material was anodized in a 0.3 M aqueous oxalic acid solution under the conditions of a direct current of 40 V and a temperature of 16 ° C. for 30 seconds (oxide film growth step). This pore size expansion treatment step and oxide film growth treatment step are repeated a total of four times, and finally the pore size expansion treatment step is performed to obtain anodized alumina having substantially conical pores with an average interval of 100 nm and a depth of 200 nm. A roll-shaped mold formed on the surface was obtained.

[Production Example 2] Preparation of active energy ray-curable composition 20 parts by mass of a mixture of dipentaerythritol pentaacrylate and dipentaerythritol hexaacrylate, 19 parts by mass of a mixture of pentaerythritol triacrylate and pentaerythritol tetraacrylate, polyethylene glycol. 40 parts by mass of diacrylate and 20 parts by mass of dimethylacrylamide are mixed, and 1 part by mass of a first photopolymerization initiator (trade name "Irgacure 184", manufactured by BASF) and a second photopolymerization initiator (trade name) are further mixed. Add 0.5 parts by mass of "Irgacure 819" (manufactured by BASF) and 0.1 parts by mass of an internal mold release agent (trade name "TDP-2", manufactured by Nikko Chemicals Co., Ltd.) and mix them to cure active energy rays. A sex composition was prepared.

[Example 1]
A protective film (trade name "FSA-020M", manufactured by Futamura Chemical Co., Ltd., width 350 mm) was placed around the roll-shaped mold obtained in Production Example 1. The protective film was wound from the upstream side in the rotation direction of the roll-shaped mold to the downstream side in the rotation direction, and the length of the protective film was twice the outer peripheral length of the roll-shaped mold.
Next, a roll-shaped mold having a protective film on the surface was attached to the manufacturing apparatus shown in FIG. 2, the temperature of the mold was raised to 75 ° C., and the base material (trade name "Cosmo Shine A4300", Toyobo Co., Ltd.) , Polyethylene terephthalate base material, thickness 75 μm) was bridged over a nip roll, a roll-shaped mold and a peeling roller.
Next, the nip roll and the peeling roller were brought close to the roll-shaped mold, and the base material was pressed against the roll-shaped mold. The tip of the protective film and the base material were attached with an adhesive tape or the like, and the protective film was peeled off from a roll-shaped mold while running the base material.
Next, the active energy ray-curable composition obtained in Production Example 2 is supplied from the tank between the roll-shaped mold and the base material, pressed by a nip roll, and the base material is run while running the active energy ray irradiation device. The active energy ray-curable composition was cured by irradiating with ultraviolet rays, and the obtained cured product was peeled off from the mold to obtain an article having an uneven structure.
As a result, when the protective film is peeled off, the adhesive does not remain on the surface of the mold, and foreign matter generated during the manufacture of the mold can be removed, and an article (moss eye film) having a defect-free uneven structure can be obtained. I was able to get it.

[Comparative Example 1]
The same operation as in Example 1 was carried out except that a self-adhesive film (trade name “FSA-100M”, manufactured by Futamura Chemical Co., Ltd.) was used as the protective film.
As a result, when the protective film was peeled off, the adhesive remained on the surface of the mold, and it was not possible to obtain an article having an uneven structure without defects.

[Comparative Example 2]
The same operation as in Example 1 was carried out except that a self-adhesive film (trade name "FSA-150M", manufactured by Futamura Chemical Co., Ltd.) was used as the protective film.
As a result, when the protective film was peeled off, the adhesive remained on the surface of the mold, and it was not possible to obtain an article having an uneven structure without defects.

[Comparative Example 3]
The same operation as in Example 1 was carried out except that a film in which a polypropylene film (thickness 25 μm) and an aluminum foil (thickness 12 μm) were laminated was used as the protective film.
As a result, when the protective film was peeled off, foreign matter generated during the manufacture of the mold remained on the surface of the mold, and it was not possible to obtain an article having an uneven structure without defects.

11 Mold 13 Protective film 13a Protective film rear end 13b Protective film tip 21 Tank 23 Active energy ray irradiator 25 Nip roll 27 Peeling roller 29 Base material

Claims (6)

A method for producing an article having a concavo-convex structure, which comprises the following steps A to C in sequence. Step A: A self-adhesive film that increases the adhesive strength as a protective film on the surface of a mold for forming an uneven structure by transfer in an environment of 0 ° C to 40 ° C, and is acrylic at 23 ° C. A step of applying the self-adhesive film having an adhesive force of the self-adhesive film to a plate of 0.3 N / 25 mm or less. Step B: A step of raising the temperature of the mold with a protective film obtained in the step A to 50 ° C. to 90 ° C. and peeling the protective film from the mold. Step C: A step of supplying the active energy ray-curable composition to the surface of the mold and curing the active energy ray-curable composition. The method for manufacturing an article having a concavo-convex structure according to claim 1 , wherein the concavo-convex structure is a moth-eye structure. The method for producing an article having a concavo-convex structure according to claim 1 or 2 , wherein the mold is in a roll shape. The method for producing an article having an uneven structure according to any one of claims 1 to 3, wherein the adhesive force of the self-adhesive film to the acrylic plate at 75 ° C. is 0.4 N / 25 mm or more. The method for producing an article having an uneven structure according to any one of claims 1 to 4 , wherein the pressure-sensitive adhesive of the self-adhesive film is an elastomer. The method for producing an article having an uneven structure according to any one of claims 1 to 5 , wherein the article having an uneven structure is an antireflection film.

Images