JP2013224015A - Light transmissive film and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for continuously manufacturing a light transmissive film having fine uneven structures with different heights on a surface from a single mold, and to provide the light transmissive film.SOLUTION: In a method for manufacturing a light transmissive film 40, a cured resin layer 44 where reversed structures of a mold are transferred is formed on a surface of a base film 42 so that fine uneven structures having different heights are formed in the longitudinal direction F of the film while repeating: a holding step of holding a fine uneven structure raw material containing a mold dissolving ingredient between the mold having a reversed structure of the fine uneven structure on its surface and the base film 42; a transferring step of obtaining the light transmissive film 40 where the cured resin layer 44 in which the reversed structure of the mold is transferred is formed on the surface of the base film 42 by heating and/or curing the fine uneven structure raw material; and a separating step of separating the light transmissive film 40 and the mold. In the light transmissive film 40, heights of the fine uneven structures are different in the longitudinal direction F of the film.

Description

  The present invention relates to a light transmissive film having a fine concavo-convex structure on its surface and a method for producing the same.

  In recent years, it has been known that an article such as a light transmissive film having a fine concavo-convex structure with a period equal to or less than the wavelength of visible light on the surface exhibits an antireflection effect, a lotus effect, and the like. In particular, it is known that a concavo-convex structure called a moth-eye structure is an effective antireflection means by continuously increasing the refractive index from the refractive index of air to the refractive index of the material of the article.

As a method for producing a light transmissive film having a fine concavo-convex structure on its surface, for example, a method having the following steps (i) to (iii), that is, a photo nanoimprint method is known (Patent Document 1).
(I) A step of sandwiching an active energy ray-curable composition between a mold having an inverted structure of a fine concavo-convex structure on the surface and a base film serving as a main body of the light transmissive film.
(Ii) The active energy ray-curable composition is irradiated with active energy rays such as ultraviolet rays, and the active energy ray-curable composition is cured to form a cured resin layer having a fine concavo-convex structure; Obtaining step.
(Iii) A step of separating the light transmissive film and the mold.

  Also known is a thermal nanoimprint method in which a thermoplastic resin is used instead of the active energy ray-curable composition, the mold is heated to a temperature at which the thermoplastic resin flows, and the fine concavo-convex structure is transferred (Patent Document 2). .

JP 2007-076089 A JP 2001-26052 A

By the way, the optimum value of the height of the fine concavo-convex structure of the light transmissive film varies depending on the pitch of the fine concavo-convex structure and the use of the light transmissive film. For example, when compared at the same pitch, the higher the fine concavo-convex structure, the higher the aspect ratio, and the higher antireflection performance can be obtained. However, when the height of the fine concavo-convex structure is too high, problems such as a decrease in scratch resistance also occur.
Therefore, the optimum height of the fine concavo-convex structure varies depending on the use of the light transmissive film.

However, in the optical nanoimprint method described in Patent Document 1 and the thermal nanoimprint method described in Patent Document 2, the shape (height) of the fine concavo-convex structure transferred from one mold is usually one type, and different heights. It is not possible to obtain a light transmissive film to which the fine concavo-convex structure is transferred.
Therefore, in order to manufacture a light-transmitting film according to each application, it is necessary to prepare a mold having an inverted structure of a fine concavo-convex structure having a height optimal for the application.

  The present invention provides a method for continuously producing a light transmissive film having a fine concavo-convex structure with different heights on a surface from a single mold, and a light transmissive film.

  As a result of intensive studies, the present inventors have incorporated a component that dissolves the mold surface into an active energy ray-curable composition or a fine concavo-convex structure raw material such as a thermoplastic resin to dissolve the mold surface during shaping. Thus, the surface shape of the mold was changed, and as a result, it was found that a light transmissive film having a fine concavo-convex structure with a different height on the surface was obtained, and the present invention was completed.

That is, the method for producing a light transmissive film of the present invention is a method for producing a light transmissive film in which a cured resin layer having a fine concavo-convex structure is formed on the surface of a base film, and the fine concavo-convex on the surface. A sandwiching step of sandwiching a fine concavo-convex structure raw material containing a mold-dissolving component between a mold having an inverted structure of the structure and a substrate film, heating the fine concavo-convex structure raw material, and / or fine concavo-convex structure raw material A transfer process for obtaining a light transmissive film in which a cured resin layer having a reverse structure of the mold transferred thereon is formed on the surface of the base film by irradiating with active energy rays and curing, and the obtained light transmissive film And a separation step for separating the mold, and while repeating the sandwiching step, the transfer step, and the separation step, fine uneven structures having different heights are formed in the longitudinal direction of the film. So that the, and forming a cured resin layer inversion structure is transferred in the mold to the substrate film surface.
Here, as the pinching process, the transfer process, and the separation process are repeated, the inversion structure of the mold is transferred so that a fine concavo-convex structure whose height continuously changes in the longitudinal direction of the film is formed. It is preferable to form a resin layer on the substrate film surface.
Moreover, it is preferable that the inverted structure of the fine concavo-convex structure on the mold surface is made of anodized alumina.
Furthermore, it is preferable that the mold dissolving component is a phosphate ester compound that satisfies the following condition (a).
Condition (a): The mold mass after dipping the mold in a phosphoric acid ester compound at 50 ° C. for 22 hours is reduced by 0.01% or more compared with that before dipping.

  Moreover, it is preferable that the said phosphate ester compound is a polyoxyethylene alkyl phosphate ester compound represented by following formula (1).

  In Formula (1), R1 is an alkyl group, m is 1-20, and n is 1-3.

The light transmissive film of the present invention is a light transmissive film in which a cured resin layer having a fine concavo-convex structure is formed on the surface of a base film, and the fine concavo-convex structure is a fine concavo-convex structure on a mold surface. The height of the fine concavo-convex structure is different in the longitudinal direction of the film.
Here, it is preferable that the height of the fine concavo-convex structure continuously changes in the longitudinal direction of the film.

  ADVANTAGE OF THE INVENTION According to this invention, the method of manufacturing continuously the light transmissive film which has the fine concavo-convex structure in which height differs from a single mold on the surface, and a light transmissive film can be provided.

It is sectional drawing which shows the manufacturing process of the mold which has an anodized alumina on the surface. It is a block diagram which shows an example of the manufacturing apparatus of a light transmissive film. It is sectional drawing which shows an example of the fixed area | region part of the light transmissive film of this invention. It is sectional drawing which shows an example of the light transmissive film of this invention manufactured continuously. It is a figure explaining the other manufacturing method of a light transmissive film. It is a scanning electron microscope image of the mold surface before an immersion test.

Hereinafter, the present invention will be described in detail.
In the present specification, “(meth) acrylate” means acrylate and methacrylate, and “light-transmitting” means that light having a wavelength of at least 400 to 1170 nm is transmitted. "Means visible light, ultraviolet light, electron beam, plasma, heat ray (infrared ray, etc.) and the like.

[Method for producing light transmissive film]
The manufacturing method of the light transmissive film of this invention is a method of manufacturing the light transmissive film by which the cured resin layer which has a fine concavo-convex structure was formed in the surface of a base film by the nanoimprint method.
The nanoimprint method used in the present invention may be an optical nanoimprint method or a thermal nanoimprint method, but the optical nanoimprint method is preferably used from the viewpoint of transferability and productivity. Hereinafter, the present invention will be described in detail along an example of an optical nanoimprint method.
Moreover, the fine concavo-convex structure of the light-transmitting film obtained by the present invention may be convex or concave. The convex mold has the advantage of easily removing dirt adhered to the surface, and the concave mold has the advantage of excellent scratch resistance. Therefore, an appropriate mold can be selected according to the use of the light-transmitting film. The following example demonstrates an example of the manufacturing method of the light transmissive film which has a convex-shaped fine uneven structure.

The manufacturing method of the light transmissive film of this invention has the following process (i)-(iii).
(I) A sandwiching step of sandwiching a fine concavo-convex structure raw material containing a mold dissolution component between a mold having a reverse structure of a fine concavo-convex structure on the surface and a base film.
(Ii) Irradiating active energy rays to the fine concavo-convex structure raw material, curing the fine concavo-convex structure raw material, and obtaining a light-transmitting film in which a cured resin layer to which the inverted structure of the mold is transferred is formed on the surface of the base film Transfer process.
(Iii) A separation step of separating the obtained light transmissive film and the mold.

In the method for producing a light transmissive film of the present invention, the mold inversion structure is formed so that a fine concavo-convex structure having different heights is formed in the longitudinal direction of the film while the pinching process, the transfer process, and the separation process are repeated. The transferred cured resin layer is formed on the substrate film surface.
Here, the “longitudinal direction of the film” is the production direction of the light transmissive film.
Further, the “height of the fine concavo-convex structure” means the height of the convex portion constituting the fine concavo-convex structure when the fine concavo-convex structure is convex, and the fine concavo-convex structure when the fine concavo-convex structure is concave. It is the depth of the recessed part which comprises a structure.

That is, in the present invention, as the light-transmitting film is manufactured, the cured resin layer to which the reversal structure of the mold is transferred is used as the base film so that the height of the fine uneven structure changes, specifically, the height decreases. Form on the surface. At this time, it is preferable to form a cured resin layer on the surface of the base film so that a fine uneven structure whose height continuously changes in the longitudinal direction of the film is formed. It is particularly preferable to form the cured resin layer on the surface of the base film so that a fine concavo-convex structure in which the height continuously decreases for each certain region while the concavo-convex structure is formed. If a fine concavo-convex structure having a uniform height is formed in a certain region, the performance of the obtained light-transmitting film is easily stabilized. In particular, it is preferable that a fine concavo-convex structure having a uniform height is formed in a region of 0.5 cm 2 or more, and a region of 1.0 cm 2 or more is more preferable. The upper limit of the certain region is not particularly limited, and may be set according to the use of the light transmissive film.

In the present invention, the “fine concavo-convex structure having a uniform height” refers to a state in which the difference in height of the fine concavo-convex structure is 10 nm or less.
In addition, when the pitch of the fine concavo-convex structure is the same, the reflectance varies depending on the height of the fine concavo-convex structure, and thus the reflectance of the light transmissive film can be used as an index of the height of the fine concavo-convex structure. In the present invention, the case where the unevenness of reflectance at a wavelength of 550 nm is within 0.5% is defined as a state in which the height of the fine concavo-convex structure is uniform.

As described above, the method for producing a light-transmitting film of the present invention uses a fine concavo-convex structure raw material containing a mold-dissolving component in the transfer step, and repeats the sandwiching step, the transfer step, and the separation step. A cured resin layer to which the inverted structure of the mold is transferred is formed on the surface of the base film so that fine uneven structures having different heights in the longitudinal direction are formed. By using a material with fine concavo-convex structure containing a mold-dissolving component, the mold surface dissolves due to the mold-dissolving component while manufacturing the light-transmitting film, and the mold reversal structure (fine concavo-convex structure) changes. Will decrease. As a result, a light-transmitting film having a fine concavo-convex structure with different heights on the surface in the longitudinal direction of the film can be continuously obtained from a single mold.
Hereinafter, the fine concavo-convex structure raw material, the base film, the mold, and the manufacturing apparatus used in the present invention will be specifically described.

<Fine uneven structure material>
When producing a light-transmitting film by the optical nanoimprint method, an active energy ray-curable composition is used as the fine concavo-convex structure raw material.
The active energy ray-curable composition (hereinafter simply referred to as “curable composition”) contains a mold-dissolving component, a polymerizable compound, and a polymerization initiator.

(Mold melting component)
The mold dissolving component is not particularly limited as long as it can dissolve the mold, and is appropriately selected according to the material of the mold to be used. Examples of the material of the mold include metals (including those having an oxide film formed on the surface), quartz, glass, resin, ceramics, and the like, but it is preferable to use anodized alumina as described later.
As a mold dissolution component suitable for anodized alumina, phosphoric acid or a phosphoric acid ester compound containing phosphoric acid is suitable. Although it does not specifically limit as another function of a phosphate ester compound, For example, it can use as an internal mold release agent.
Hereinafter, the case where a fine concavo-convex structure made of anodized alumina is formed on the surface as a mold and the case where phosphoric acid is used as a mold dissolution component will be described in more detail.

  Alumina is known to dissolve in acids and alkalis, and among them, phosphoric acid has a high dissolving power (see non-patent literature (Air Conditioning / Hygiene Engineering, Vol. 79, No. 9, p70)). When the mold surface is melted and the reversal structure (fine concavo-convex structure) of the mold is changed, fine concavo-convex structures having different heights can be continuously transferred from a single mold.

Therefore, when using a mold having a fine concavo-convex structure made of anodized alumina, it is preferable to use a curable composition containing phosphoric acid as a mold dissolving component. As the mold dissolving component, phosphoric acid itself may be added to the curable composition, but it is difficult to uniformly dissolve phosphoric acid in the curable composition, or the phosphoric acid is added to the curable composition. There is a possibility of water mixing. Therefore, it is preferable to add a phosphate ester compound containing phosphoric acid to the curable composition. Furthermore, in order to uniformly dissolve the phosphate ester compound, the phosphate ester compound and other components (such as a polymerizable compound and a polymerization initiator described later) are mixed in the stage of preparing the curable composition. Is preferred.

It is essential for the phosphate ester compound used in the present invention to dissolve the mold surface. Whether or not the mold is dissolved is affected by the amount of phosphoric acid contained in the phosphate ester compound, but it is preferable to actually immerse the mold in the phosphate ester compound and examine the mass change for judgment.
There exists a tendency for a mold to melt | dissolve early, during manufacture of a light transmissive film, so that a dissolving power is large. When the dissolving power is low, the mold surface is not melted and the fine uneven structure of the mold is difficult to change, so the height of the fine uneven structure transferred to the cured resin layer is also difficult to change. On the other hand, if the dissolving power is too large, the mold surface will be excessively dissolved, and the fine concavo-convex structure of the mold will change drastically (the height will become extremely small), which is large in the fine concavo-convex structure transferred to the cured resin layer. Spots are likely to occur.

Therefore, in the present invention, it is preferable to use a phosphate ester compound that satisfies the following condition (a), which serves as an index of dissolving power, as a mold dissolving component.
Condition (a): The mold mass after dipping the mold in a phosphoric acid ester compound at 50 ° C. for 22 hours is reduced by 0.01% or more compared with that before dipping.

Whether the condition (a) is satisfied can be determined as follows.
That is, after the mold was immersed in a phosphoric ester compound at 50 ° C. for 22 hours and subjected to the immersion test, the mold was taken out and washed, and the mass of the mold before and after the immersion test was measured. Find the rate. If the reduction rate is 0.01% or more, it is determined that the condition (a) is satisfied.
Reduction rate (%) = {(Mass of mold before immersion−Mass of mold after washing) / Mass of mold before immersion} × 100

If the reduction rate is 0.01% or more, the phosphate ester compound has an appropriate dissolving power, so the mold surface is easily dissolved at an appropriate speed while repeating the sandwiching process, the transfer process and the separation process. Become. Therefore, it becomes easy to obtain a light-transmitting film in which a cured resin layer to which a fine concavo-convex structure having a different height in the longitudinal direction of the film is transferred is formed on the surface of the base film. The reduction rate is preferably 0.1% or more.
On the other hand, the upper limit of the reduction rate is preferably 1% or less, more preferably 0.7% or less, from the viewpoint of suppressing excessive dissolution of the mold surface.

  In addition, what is necessary is just to immerse a mold as it is, when a phosphoric acid ester compound is a liquid. On the other hand, when the phosphate ester compound is solid, the phosphate ester compound is heated or depressurized to form a liquid, or the phosphate ester compound is dissolved in a solvent that does not affect the mold as a solution. What is necessary is just to immerse a mold in. In particular, when the phosphate ester compound is dissolved in the solvent, the higher the concentration of the phosphate ester compound as possible, the quicker the determination of the solubility of the phosphate ester compound in the mold can be made.

  As the phosphate ester compound, those satisfying the condition (a) are preferable, and among them, a polyoxyethylene alkyl phosphate compound represented by the following formula (1) (hereinafter referred to as “compound (1)”) is particularly preferable. Is preferably used because it also exhibits an effect as a release agent.

In formula (1), R1 is an alkyl group. R1 is preferably an alkyl group having 3 to 18 carbon atoms.
Moreover, in Formula (1), m shows the average addition mole number of ethylene oxide, is 1-20, and 1-10 are preferable. On the other hand, n is 1-3.

  Compound (1) may be a monoester, a diester, or a triester. Moreover, when it is a diester body or a triester body, several polyoxyethylene alkyl residues in 1 molecule may each differ.

  If compound (1) is used as a mold-dissolving component, the releasability between the cured resin layer, which is a cured product of the curable composition, and the mold is further improved, and it is suitable for forming a fine concavo-convex structure. Moreover, since the load at the time of releasing from a mold becomes very low, the light transmissive film in which the fine concavo-convex structure with few defects was transferred can be obtained with high productivity. Furthermore, the release performance can be maintained for a long time by using the compound (1).

Among the compounds (1), a compound that satisfies the above-mentioned condition (a) and can be used as a mold dissolving component can be obtained as a commercial product. For example, “TDP-10”, “TDP-8”, “TDP-6”, “TDP-2”, “DDP-10”, “DDP-8”, “DDP-6” manufactured by Nikko Chemicals Corporation, “DDP-4”, “DDP-2”; “INT-1856” manufactured by Accel Corporation; “JP506-H” manufactured by Johoku Chemical Industry Co., Ltd.
A compound (1) may be used individually by 1 type, and may use 2 or more types together.

By the way, the mold dissolution rate depends on the content of the mold-dissolving component in the curable composition, the amount of the mold-dissolving component oozing out (bleed out) on the surface in contact with the mold during the transfer process, and the like. . Therefore, in order to transfer the fine uneven structure having different heights to the cured resin layer while repeating the sandwiching process, the transfer process, and the separation process, the content of the mold dissolving component and the amount of bleed out are important.
The amount of bleed out depends on the compatibility of the polymerizable compound and the mold dissolving component. Since the amount of bleed out increases as the compatibility is poor, the mold is likely to melt. In particular, when a phosphoric acid ester compound containing phosphoric acid is used as a mold dissolving component, the amount of bleed out changes significantly depending on the compatibility with the polymerizable compound. Therefore, the dissolution rate of the mold can be controlled by adjusting the combination of the phosphoric acid ester compound containing phosphoric acid and the polymerizable compound.

  As a method for confirming the compatibility of the phosphoric acid ester compound containing phosphoric acid, a method may be considered in which the phosphoric acid ester compound is added to the curable composition and judged by transparency when stirred. The higher the compatibility, the higher the transparency of the curable composition. Examples of the evaluation of transparency include a method of measuring transmittance using light scattering or a spectrophotometer. Moreover, when there is little addition amount of the phosphoric acid ester compound containing an actual phosphoric acid, it may be added more experimentally and a compatibility may be judged. For example, when the transparency is judged by the transmittance, if the transmittance at a wavelength of 500 nm when adding 3 parts by mass of a phosphate ester compound containing phosphoric acid to the curable composition and stirring is 95% or more, the compatibility Therefore, the amount of bleed-out is suppressed and mold dissolution is difficult to occur. On the other hand, a transmittance of less than 95% is preferable because the compatibility is poor and the bleed-out is likely to occur and the mold melts easily. In order to efficiently transfer the fine concavo-convex structure having different heights to the cured resin layer while repeating the sandwiching process, the transfer process, and the separation process, the transmittance is more preferably 50% or less.

0.01 mass part or more is preferable with respect to 100 mass parts of polymeric compounds mentioned later, and, as for content of a mold melt | dissolution component, 0.5 mass part or more is more preferable. The dissolution rate tends to increase as the content of the mold dissolution component increases. However, if the mold dissolving component is contained more than necessary, the mold surface is excessively dissolved, and the fine concavo-convex structure may be lost, or the fine concavo-convex structure having a desired height may not be transferred. Therefore, the content of the mold dissolving component is preferably 3 parts by mass or less.
On the other hand, the bleed-out amount varies depending on the compatibility between the polymerizable compound and the mold-dissolving component, and the bleed-out amount increases as the compatibility becomes worse, so that the dissolution rate tends to increase. In particular, the amount of bleed out of the phosphate ester compound varies significantly depending on the compatibility with the polymerizable compound. Therefore, the dissolution rate of the mold can be controlled by adjusting the combination of the phosphate ester compound and the polymerizable compound.

(Polymerizable compound)
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.

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.

(Polymerization initiator)
When utilizing 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) carbonyl compounds such as benzophenone and 2-hydroxy-2-methyl-1-phenylpropan-1-one; sulfur compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; 2,4,6-trimethylbenzoyldiphenyl Examples include phosphine oxide and benzoyldiethoxyphosphine 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.

  As for content of a polymerization initiator, 0.1-10 mass parts is preferable with respect to 100 mass parts of polymeric compounds. When the content of the polymerization initiator is less than 0.1 parts by mass, the polymerization is difficult to proceed. On the other hand, when the content of the polymerization initiator exceeds 10 parts by mass, the cured resin layer may be colored or the mechanical strength may be lowered.

(Other ingredients)
If necessary, the curable composition of the present invention comprises a non-reactive polymer, an active energy ray sol-gel reactive composition, an ultraviolet absorber and / or a light stabilizer, a lubricant, a plasticizer, an antistatic agent, and a flame retardant. , Flame retardant aids, polymerization inhibitors, fillers, silane coupling agents, colorants, reinforcing agents, inorganic fillers, additives such as fluorine compounds to improve antifouling properties, fine particles, impact modifiers And the like, and may contain a small amount of a solvent.

Non-reactive polymer:
Examples of non-reactive polymers include acrylic resins, styrene resins, polyurethanes, cellulose resins, polyvinyl butyral, polyesters, thermoplastic elastomers, and the like.

Active energy ray sol-gel reactive composition:
Examples of the active energy ray sol-gel reactive composition include alkoxysilane compounds and alkyl silicate compounds.
Examples of the alkoxysilane compound include a compound represented by the following formula (2) (hereinafter referred to as “compound (2)”).
R2xSi (OR3) y (2)
However, in Formula (2), R2 and R3 represent a C1-C10 alkyl group, respectively, and x and y are integers which satisfy | fill the relationship of x + y = 4.

  Specific examples of the compound (2) include tetramethoxysilane, tetra-i-propoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-t-butoxysilane, Examples include methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, trimethylmethoxysilane, trimethylpropoxysilane, and trimethylbutoxysilane.

Examples of the alkyl silicate compound include a compound represented by the following formula (3) (hereinafter referred to as “compound (3)”).
R4O [Si (OR6) (OR7) O] zR5 (3)
However, in formula (3), R4 to R7 each represents an alkyl group having 1 to 5 carbon atoms, and z represents an integer of 3 to 20.

  Specific examples of the compound (3) include methyl silicate, ethyl silicate, isopropyl silicate, n-propyl silicate, n-butyl silicate, n-pentyl silicate, acetyl silicate and the like.

UV absorber and / or light stabilizer:
The ultraviolet absorber and / or the light stabilizer plays a role of imparting weather resistance such as suppression of yellowish color and suppression of increase in haze.
Examples of ultraviolet absorbers and / or light stabilizers include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, benzoate ultraviolet absorbers, and hindered amine light stabilizers. Commercially available products include UV absorbers such as “Tinuvin 400”, “Tinubin 479” and “Tinubin 109” manufactured by Ciba Specialty Chemicals Co., Ltd .; Examples thereof include light stabilizers such as “Tinuvin 152” and “Tinuvin 292” manufactured by the company.
A ultraviolet absorber and / or a light stabilizer may be used individually by 1 type, and may use 2 or more types together.

The content of the ultraviolet absorber and / or the light stabilizer is preferably 0.01 to 5 parts by weight, more preferably 0.01 to 3 parts by weight, and 0.01 to 1 part by weight with respect to 100 parts by weight of the polymerizable compound. Part is more preferable, and 0.01 to 0.5 part by mass is particularly preferable. When these contents are 0.01 parts by mass or more, it is easy to obtain an effect of improving weather resistance such as suppression of yellowish color and suppression of increase in haze. On the other hand, if these content is 5 mass parts or less, since a curable composition will fully harden | cure, it is easy to suppress the abrasion-resistant fall of a cured resin layer. Moreover, the fall of the fingerprint wiping property in a weather resistance test can also be suppressed.

(Hydrophobic material)
In order to set the water contact angle of the surface of the fine uneven structure of the cured resin layer to 90 ° or more, a composition containing a fluorine-containing compound or a silicone compound is used as the curable composition capable of forming a hydrophobic material. It is preferable.

Fluorine-containing compounds:
As the fluorine-containing compound, a compound having a fluoroalkyl group represented by the following formula (4) is preferable.
-(CF2) q-X (4)
However, in Formula (4), X represents a fluorine atom or a hydrogen atom, q represents an integer greater than or equal to 1, 1-20 are preferable, 3-10 are more preferable, and 4-8 are especially preferable.

  Examples of the fluorine-containing compound include a fluorine-containing monomer, a fluorine-containing silane coupling agent, a fluorine-containing surfactant, and a fluorine-containing polymer.

Examples of the fluorine-containing monomer include a fluoroalkyl group-substituted vinyl monomer and a fluoroalkyl group-substituted ring-opening polymerizable monomer.
Examples of the fluoroalkyl group-substituted vinyl monomer include fluoroalkyl group-substituted (meth) acrylates, fluoroalkyl group-substituted (meth) acrylamides, fluoroalkyl group-substituted vinyl ethers, and fluoroalkyl group-substituted styrenes.
Examples of the fluoroalkyl group-substituted ring-opening polymerizable monomer include fluoroalkyl group-substituted epoxy compounds, fluoroalkyl group-substituted oxetane compounds, and fluoroalkyl group-substituted oxazoline compounds.

As the fluorine-containing monomer, a fluoroalkyl group-substituted (meth) acrylate is preferable, and a compound represented by the following formula (5) is particularly preferable.
CH2 = C (R8) C (O) O- (CH2) p- (CF2) q-X (5)
However, in formula (5), R8 represents a hydrogen atom or a methyl group, X represents a hydrogen atom or a fluorine atom, p represents an integer of 1 to 6, preferably 1 to 3, and more preferably 1 or 2. , Q represents an integer of 1 to 20, preferably 3 to 10, and more preferably 4 to 8.

As the fluorine-containing silane coupling agent, a fluoroalkyl group-substituted silane coupling agent is preferable, and a compound represented by the following formula (6) is particularly preferable.
(R9) aR10bSiYc (6)
However, in Formula (6), R9 represents a C1-C20 fluorine-substituted alkyl group which may contain one or more ether bonds or ester bonds. Examples of R9 include 3,3,3-trifluoropropyl group, tridecafluoro-1,1,2,2-tetrahydrooctyl group, 3-trifluoromethoxypropyl group, 3-trifluoroacetoxypropyl group and the like. .
R10 represents an alkyl group having 1 to 10 carbon atoms. Examples of R10 include a methyl group, an ethyl group, and a cyclohexyl group.

Y represents a hydroxyl group or a hydrolyzable group.
Examples of the hydrolyzable group include an alkoxy group, a halogen atom, and R11C (O) O (wherein R11 represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms).
Examples of the alkoxy group include methoxy group, ethoxy group, propyloxy group, i-propyloxy group, butoxy group, i-butoxy group, t-butoxy group, pentyloxy group, hexyloxy group, cyclohexyloxy group, heptyloxy group, Examples include octyloxy group, 2-ethylhexyloxy group, nonyloxy group, decyloxy group, 3,7-dimethyloctyloxy group, lauryloxy group, and the like.
Examples of the halogen atom include Cl, Br, I and the like.
Examples of R11C (O) O include CH3C (O) O, C2H5C (O) O, and the like.

  a, b, and c are integers satisfying a + b + c = 4 and satisfying a ≧ 1, c ≧ 1, and preferably a = 1, b = 0, and c = 3.

  Fluorine-containing silane coupling agents include 3,3,3-trifluoropropyltrimethoxysilane, 3,3,3-trifluoropropyltriacetoxysilane, dimethyl-3,3,3-trifluoropropylmethoxysilane, Examples include decafluoro-1,1,2,2-tetrahydrooctyltriethoxysilane.

Examples of the fluorine-containing surfactant include a fluoroalkyl group-containing anionic surfactant and a fluoroalkyl group-containing cationic surfactant.
Examples of the fluoroalkyl group-containing anionic surfactant include a fluoroalkylcarboxylic acid having 2 to 10 carbon atoms or a metal salt thereof, perfluorooctanesulfonyl glutamate disodium, 3- [omega-fluoroalkyl (C6-C11) oxy]- Sodium 1-alkyl (C3-C4) sulfonate, sodium 3- [omega-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonate, fluoroalkyl (C11-C20) carboxylic acid or its metal Salt, perfluoroalkylcarboxylic acid (C7 to C13) or metal salt thereof, perfluoroalkyl (C4 to C12) sulfonic acid or metal salt thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- (2-hydroxy Ethyl) full Looctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Can be mentioned.

  Examples of fluoroalkyl group-containing cationic surfactants include aliphatic quaternary ammonium salts such as fluoroalkyl group-containing aliphatic primary, secondary or tertiary amine acids, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salts. Benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt and the like.

  Fluorine-containing polymers include polymers of fluoroalkyl group-containing monomers, copolymers of fluoroalkyl group-containing monomers and poly (oxyalkylene) group-containing monomers, and copolymers of fluoroalkyl group-containing monomers and crosslinking reactive group-containing monomers. A polymer etc. are mentioned. The fluorine-containing polymer may be a copolymer with another copolymerizable monomer.

As the fluorine-containing polymer, a copolymer of a fluoroalkyl group-containing monomer and a poly (oxyalkylene) group-containing monomer is preferable.
As the poly (oxyalkylene) group, a group represented by the following formula (7) is preferable.
-(OR12) r -... (7)
However, in Formula (7), R12 represents a C2-C4 alkylene group, r represents an integer greater than or equal to 2. Examples of R12 include -CH2CH2-, -CH2CH2CH2-, -CH (CH3) CH2-, -CH (CH3) CH (CH3)-and the like.

The poly (oxyalkylene) group may be composed of the same oxyalkylene unit (OR12) or may be composed of two or more oxyalkylene units (OR12). The arrangement of two or more oxyalkylene units (OR12) may be a block or random.

Silicone compounds:
Examples of the silicone compound include (meth) acrylic acid-modified silicone, silicone resin, silicone silane coupling agent and the like.
Examples of the (meth) acrylic acid-modified silicone include silicone (di) (meth) acrylate.

(Hydrophilic material)
In order to make the water contact angle on the surface of the fine uneven structure of the cured resin layer 25 ° or less, it is preferable to use a composition containing at least a hydrophilic monomer as a curable composition capable of forming a hydrophilic material. . From the viewpoint of scratch resistance and imparting water resistance, those containing a cross-linkable polyfunctional monomer are more preferable. In addition, the same (namely, hydrophilic polyfunctional monomer) may be sufficient as the polyfunctional monomer which can be bridge | crosslinked with a hydrophilic monomer. Furthermore, the curable composition may contain other monomers.

As the curable composition capable of forming a hydrophilic material, it is more preferable to use a composition containing the following polymerizable compound.
10 to 50% by mass of a tetrafunctional or higher polyfunctional (meth) acrylate,
30-80% by weight of bifunctional or higher hydrophilic (meth) acrylate,
A polymerizable compound comprising a total of 100% by mass of 0 to 20% by mass of a monofunctional monomer.

Examples of tetrafunctional or higher polyfunctional (meth) acrylates include ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, pentaerythritol ethoxytetra (meth) acrylate, dipentaerythritol hydroxypenta (meth) acrylate, di Pentaerythritol hexa (meth) acrylate, condensation reaction mixture of succinic acid / trimethylolethane / acrylic acid in a molar ratio of 1: 2: 4, urethane acrylates ("EBECRYL220", "EBECRYL1290", "manufactured by Daicel-Cytec Corporation", " EBECRYL1290K ”,“ EBECRYL5129 ”,“ EBECRYL8210 ”,“ EBECRYL8301 ”,“ KRM8200 ”), polyether acrylates ( "EBECRYL81" manufactured by Issel Cytec Co., Ltd.), modified epoxy acrylates ("EBECRYL3416" manufactured by Daicel Cytech Co., Ltd.), polyester acrylates ("EBECRYL450", "EBECRYL657" manufactured by Daicel Cytec Co., Ltd., "EBECRYL800") ”,“ EBECRYL 810 ”,“ EBECRYL 811 ”,“ EBECRYL 812 ”,“ EBECRYL 1830 ”,“ EBECRYL 845 ”,“ EBECRYL 846 ”,“ EBECRYL 1870 ”), and the like.
These may be used alone or in combination of two or more.
The polyfunctional (meth) acrylate having 4 or more functional groups is more preferably a polyfunctional (meth) acrylate having 5 or more functional groups.

  The content of the tetrafunctional or higher polyfunctional (meth) acrylate is preferably 10 to 50% by mass in 100% by mass of the polymerizable compound, and more preferably 20 to 50% by mass from the viewpoint of water resistance and chemical resistance. 30-50 mass% is especially preferable. On the other hand, if the content of the tetrafunctional or higher polyfunctional (meth) acrylate is 10% by mass or more, the elastic modulus is increased and the scratch resistance is improved. If the content of the tetrafunctional or higher polyfunctional (meth) acrylate is 50% by mass or less, it is difficult for small cracks to be formed on the surface and poor appearance.

As bifunctional or more hydrophilic (meth) acrylates, “Aronix M-240” and “Aronix M260” manufactured by Toagosei Co., Ltd .; “NK Ester AT-20E” and “NK Ester” manufactured by Shin-Nakamura Chemical Co., Ltd. Examples thereof include polyfunctional acrylates having a long-chain polyethylene glycol such as “ATM-35E”, polyethylene glycol dimethacrylate, and the like.
These may be used alone or in combination of two or more.

  In the polyethylene glycol dimethacrylate, the total of the average repeating units of the polyethylene glycol chain present in one molecule is preferably 6 to 40, more preferably 9 to 30, and particularly preferably 12 to 20. If the average repeating unit of the polyethylene glycol chain is 6 or more, the hydrophilicity is sufficient and the antifouling property is improved. If the average repeating unit of the polyethylene glycol chain is 40 or less, the compatibility with a polyfunctional (meth) acrylate having 4 or more functional groups is good, and the curable composition is difficult to separate.

  30-100 mass% is preferable in 100 mass% of polymeric compounds, and, as for content of bifunctional or more hydrophilic (meth) acrylate, 40-70 mass% is more preferable. If content of bifunctional or more hydrophilic (meth) acrylate is 30 mass% or more, hydrophilicity will become sufficient and antifouling property will improve. On the other hand, if the content of the bifunctional or higher functional hydrophilic (meth) acrylate is 80% by mass or less, the elastic modulus is increased and the scratch resistance is improved.

As the monofunctional monomer, a hydrophilic monofunctional monomer is preferable.
Examples of the hydrophilic monofunctional monomer include monofunctional (meth) acrylates having a polyethylene glycol chain in an ester group such as “M-20G”, “M-90G”, and “M-230G” manufactured by Shin-Nakamura Chemical Co., Ltd. Cationic monomers such as monofunctional (meth) acrylates having a hydroxyl group in the ester group such as hydroxyalkyl (meth) acrylate, monofunctional acrylamides, methacrylopropylpropyltrimethylammonium methylsulfate, methacryloyloxyethyltrimethylammonium methylsulfate, etc. It is done.
Moreover, as a monofunctional monomer, you may use viscosity modifiers, such as acryloyl morpholine and vinyl pyrrolidone, adhesive improvement agents, such as acryloyl isocyanates which improve the adhesiveness to a base film.

  The content of the monofunctional monomer is preferably 0 to 20% by mass and more preferably 5 to 15% by mass in 100% by mass of the polymerizable compound. By using a monofunctional monomer, the adhesion between the base film and the cured resin layer is improved. If the content of the monofunctional monomer is 20% by mass or less, antifouling property or scratch resistance can be obtained without a shortage of polyfunctional (meth) acrylate having 4 or more functional groups or hydrophilic (meth) acrylate having 2 or more functional groups. Fully express.

  The monofunctional monomer may be blended in the curable composition in an amount of 0 to 35 parts by mass as a low-polymerization polymer obtained by (co) polymerizing one type or two or more types. As a polymer having a low polymerization degree, a monofunctional (meth) acrylate having a polyethylene glycol chain in an ester group such as “M-230G” manufactured by Shin-Nakamura Chemical Co., Ltd., and methacrylamide propyltrimethylammonium methyl sulfate 40/60 copolymer oligomer (for example, “MG polymer” manufactured by MRC Unitech Co., Ltd.) and the like.

Since the curable composition demonstrated above contains a mold melt | dissolution component, it is easy to dissolve a mold surface moderately. As a result, the mold surface dissolves and the surface shape (fine concavo-convex structure) changes with the manufacture of the light transmissive film, so that the fine concavo-convex structure of different heights can be transferred continuously from a single mold. .
Moreover, since the phosphate ester compound also serves as a mold release agent, the mold release property between the mold and the cured resin layer can be maintained for a long time.

<Base film>
As the base film, a film having high light transmittance is preferable because active energy ray irradiation is performed through the film. For example, an acrylic film, a PET (polyethylene terephthalate) film, a polycarbonate film, a TAC (triacetyl cellulose) film, or the like is used. be able to.

<Mold>
Examples of the material for the mold include metals (including those having an oxide film formed on the surface), quartz, glass, resin, ceramics, and the like.
The mold used in the present invention can be produced by, for example, the following methods (I) and (II). Among them, the method (I) is particularly preferable from the viewpoint that the area can be increased and the production is simple.
(I) A method of forming anodized alumina having a plurality of pores (recesses) on the surface of an aluminum substrate.
(II) A method of forming a fine relief structure on the surface of a substrate by lithography.

The method (I) preferably includes the following steps (a) to (e).
(A) A step of forming an oxide film on the surface of an aluminum substrate by anodizing the aluminum substrate in an electrolytic solution under a constant voltage.
(B) A step of removing the oxide film and forming anodic oxidation pore generation points on the surface of the aluminum substrate.
(C) A step of anodizing the aluminum substrate again in the electrolytic solution to form an oxide film having pores at the pore generation points.
(D) A step of enlarging the diameter of the pores.
(E) A step of repeatedly performing steps (c) and (d) to obtain a mold in which anodized alumina having a plurality of pores is formed on the surface of an aluminum substrate.

Step (a):
As shown in FIG. 1, when the aluminum substrate 10 is anodized, an oxide film 14 having pores 12 is formed.
Examples of the shape of the aluminum substrate include a roll shape, a circular tube shape, a flat plate shape, and a sheet shape.
The aluminum base material is preferably polished by mechanical polishing, feather polishing, chemical polishing, electrolytic polishing treatment (etching treatment) or the like in order to smooth the surface state. Moreover, since the oil used when processing an aluminum base material in a defined shape may adhere, it is preferable to degrease in advance before anodizing.

The purity of aluminum is preferably 99% or more, more preferably 99.5% or more, and particularly preferably 99.8% or more. When the purity of aluminum is low, when anodized, an uneven structure having a size to scatter visible light may be formed due to segregation of impurities, or the regularity of pores obtained by anodization may be lowered.
Examples of the electrolytic solution include sulfuric acid, oxalic acid, and phosphoric acid.

When using oxalic acid as electrolyte:
The concentration of oxalic acid is preferably 0.7 M or less. When the concentration of oxalic acid exceeds 0.7M, the current value becomes too high, and the surface of the oxide film may become rough.
When the formation voltage is 30 to 60 V, anodized alumina having highly regular pores with an average interval of 100 nm can be obtained. Regardless of whether the formation voltage is higher or lower than this range, the regularity tends to decrease.
The temperature of the electrolytic solution is preferably 60 ° C. or lower, and more preferably 45 ° C. or lower. When the temperature of the electrolytic solution exceeds 60 ° C., a so-called “burn” phenomenon occurs, and the pores may be broken, or the surface may melt and the regularity of the pores may be disturbed.

When using sulfuric acid as the electrolyte:
The concentration of sulfuric acid is preferably 0.7M or less. If the concentration of sulfuric acid exceeds 0.7M, the current value may become too high to maintain a constant voltage.
When the formation voltage is 25 to 30 V, anodized alumina having highly regular pores with an average interval of 63 nm can be obtained. The regularity tends to decrease whether the formation voltage is higher or lower than this range.
The temperature of the electrolytic solution is preferably 30 ° C. or less, and more preferably 20 ° C. or less. When the temperature of the electrolytic solution exceeds 30 ° C., a so-called “burn” phenomenon occurs, and the pores may be broken or the surface may melt and the regularity of the pores may be disturbed.

Step (b):
As shown in FIG. 1, the regularity of the pores can be improved by removing the oxide film 14 once and using it as the pore generation points 16 for anodic oxidation. In addition, when not so high regularity is required, you may remove at least one part of the oxide film 14, and you may perform the process (d) mentioned later after a process (a).
Examples of the method for removing the oxide film include a method in which aluminum is not dissolved but is dissolved in a solution that selectively dissolves the oxide film and removed. Examples of such a solution include a chromic acid / phosphoric acid mixed solution.

Step (c):
As shown in FIG. 1, when the aluminum substrate 10 from which the oxide film has been removed is anodized again, an oxide film 14 having cylindrical pores 12 is formed.
Anodization may be performed under the same conditions as in step (a). Deeper pores can be obtained as the anodic oxidation time is lengthened.

Step (d):
As shown in FIG. 1, a process for expanding the diameter of the pores 12 (hereinafter referred to as a pore diameter expansion process) is performed. The pore diameter expansion treatment is a treatment for expanding the diameter of the pores obtained by anodic oxidation by immersing in a solution dissolving the oxide film. Examples of such a solution include a phosphoric acid aqueous solution of about 5% by mass.
The longer the pore diameter expansion processing time, the larger the pore diameter.

Step (e):
As shown in FIG. 1, when the anodization in the step (c) and the pore diameter expansion process in the step (d) are repeated, the pores 12 have a shape in which the diameter continuously decreases in the depth direction from the opening. An oxide film 14 is formed, and a mold body 18 having anodized alumina (aluminum porous oxide film (alumite)) on the surface of the aluminum substrate 10 is obtained.

  The total number of repetitions is preferably 3 times or more, and more preferably 5 times or more. When the number of repetitions is 2 times or less, the diameter of the pores decreases discontinuously. Therefore, the reflectance reduction effect of the fine uneven structure (moth eye structure) formed using anodized alumina having such pores is It is insufficient.

  Examples of the shape of the pore 12 include a substantially conical shape, a pyramid shape, a cylindrical shape, and the like, and a cross-sectional area of the pore in a direction orthogonal to the depth direction such as a conical shape and a pyramid shape has a depth from the outermost surface. A shape that continuously decreases in the direction is preferred.

The average interval between the pores 12 is not more than the wavelength of visible light, that is, not more than 400 nm. Pore 1
The average distance between the two is preferably 20 nm or more.
The average interval between the pores 12 was measured by measuring the distance between adjacent pores 12 (distance from the center of the pore 12 to the center of the adjacent pore 12) by electron microscope observation, and averaging these values. It is a thing.

When the average interval is 100 nm, the depth of the pores 12 is preferably 80 to 500 nm, more preferably 120 to 400 nm, and particularly preferably 150 to 300 nm.
The depth of the pore 12 is a value obtained by measuring the distance between the bottom of the pore 12 and the top of the convex portion existing between the pores 12 when observed with an electron microscope at a magnification of 30000 times. It is.
The aspect ratio of the pores 12 (depth of pores / average interval between pores) is preferably 0.8 to 5.0, more preferably 1.2 to 4.0, and 1.5 to 3.0. Is particularly preferred.

Other processes:
In the present invention, the mold body 18 obtained in the step (e) may be used as a mold as it is. However, the surface of the mold body 18 on which the fine uneven structure is formed is formed with a release agent (external release agent). It may be processed.
As the release agent, those having a functional group capable of forming a chemical bond with the anodized alumina of the aluminum substrate are preferable. Specifically, silicone resin, fluororesin, fluorine compound and the like can be mentioned. From the viewpoint of excellent releasability and excellent adhesion to the mold body, it is preferable to have a silanol group or a hydrolyzable silyl group. Among these, a fluorine compound having a hydrolyzable silyl group is particularly preferable.
Commercially available fluorine compounds having hydrolyzable silyl groups include fluoroalkyl silane, “KBM-7803” manufactured by Shin-Etsu Chemical Co., Ltd .; “OPTOOL” series manufactured by Daikin Industries, Ltd .; “manufactured by Sumitomo 3M Limited” Novec EGC-1720 "and the like.

Examples of the treatment method using a release agent include the following Method 1 and Method 2, and Method 1 is particularly preferable because the surface of the mold body on which the fine concavo-convex structure is formed can be treated with a release agent without unevenness. .
Method 1: A method in which a mold body is immersed in a dilute solution of a release agent.
Method 2: A method in which a release agent or a diluted solution thereof is applied to the surface of the mold body on the side where the fine relief structure is formed.

As the method 1, a method having the following steps (f) to (j) is preferable.
(F) A step of washing the mold main body with water.
(G) A step of blowing water on the mold body to remove water droplets attached to the surface of the mold body.
(H) A step of immersing the mold body in a diluted solution obtained by diluting a fluorine compound having a hydrolyzable silyl group with a solvent.
(I) A step of slowly lifting the immersed mold body from the solution.
(J) A step of drying the mold body.

Step (f):
Since the chemical | medical agent (Phosphate aqueous solution etc. which were used for the pore diameter expansion process), impurities (dust etc.), etc. which were used when forming a porous structure are adhering to a mold main body, this is removed by water washing.

Step (g):
Air is blown onto the mold body to remove almost all visible water droplets.

Step (h):
As a solvent for dilution, a known solvent such as a fluorine-based solvent or an alcohol-based solvent may be used. Among these, a fluorine-based solvent is preferable because it has appropriate volatility, wettability, and the like, and can be applied uniformly with an external release agent solution. Examples of the fluorine-based solvent include hydrofluoropolyether, perfluorohexane, perfluoromethylcyclohexane, perfluoro-1,3-dimethylcyclohexane, dichloropentafluoropropane, and the like.
As for the density | concentration of the fluorine compound which has a hydrolyzable silyl group, 0.01-0.2 mass% is preferable in a diluted solution (100 mass%).
The immersion time is preferably 1 to 30 minutes.
As for immersion temperature, 0-50 degreeC is preferable.

Step (i):
When the soaked mold body is pulled up from the solution, it is preferable to pull up at a constant speed using an electric puller or the like to suppress swinging during the pulling. This can reduce coating unevenness.
The pulling speed is preferably 1 to 10 mm / second.

Step (j):
In the step of drying the mold body, the mold body may be air-dried or forcibly heated and dried with a dryer or the like.
The drying temperature is preferably 30 to 150 ° C.
The drying time is preferably 5 to 300 minutes.

  In addition, it can confirm that the surface of the mold main body was processed with the mold release agent by measuring the water contact angle of the surface of the mold main body. The water contact angle on the surface of the mold body treated with the release agent is preferably 60 ° or more, and more preferably 90 ° or more. When the water contact angle is 60 ° or more, the surface of the mold body is sufficiently treated with a release agent, and the release property is improved.

<Manufacturing equipment>
The method for producing a light-transmitting film of the present invention uses the above-described curable composition containing a mold-dissolving component, and repeatedly performs a sandwiching step, a transfer step, and a separation step.
Each process is performed as follows, for example using the manufacturing apparatus shown in FIG.

  The curable composition 38 is supplied from the tank 22 between the roll-shaped mold 20 having a fine concavo-convex structure (not shown) on the surface and the strip-shaped base film 42 that moves along the surface of the roll-shaped mold 20. .

  The base film 42 and the curable composition 38 are nipped between the roll-shaped mold 20 and the nip roll 26 whose nip pressure is adjusted by the pneumatic cylinder 24, and the curable composition 38 is rolled with the base film 42. At the same time, it is uniformly distributed between the mold 20 and the concave portion of the fine concavo-convex structure of the roll-shaped mold 20 is filled.

By irradiating the active energy ray to the curable composition 38 through the base film 42 from the active energy ray irradiating device 28 installed below the roll-shaped mold 20 to cure the curable composition 38, the roll-shaped mold is obtained. The cured resin layer 44 to which the fine concavo-convex structure on the surface of 20 is transferred is formed.
By peeling the base film 42 having the cured resin layer 44 formed on the surface thereof from the roll-shaped mold 20 by the peeling roll 30, a surface having a uniform fine concavo-convex structure having a uniform height as shown in FIG. A light-transmitting film 40 is obtained.
Then, by repeating the sandwiching step, the transfer step, and the separation step, as shown in FIG. 4, a light transmissive film 40 having a different fine concavo-convex structure height in the longitudinal direction F of the film is obtained.

  As the active energy ray irradiation device 28, a high-pressure mercury lamp, a metal halide lamp, or the like is preferable. In this case, the amount of light irradiation energy is preferably 100 to 10,000 mJ / cm 2.

<Effect>
According to the method for producing a light-transmitting film of the present invention described above, a curable composition containing a mold-dissolving component is used, and the height in the longitudinal direction of the film is repeated while repeating the sandwiching process, the transfer process, and the separation process. The cured resin layer to which the reversal structure of the mold is transferred is formed on the surface of the base film so that the fine concavo-convex structures having different sizes are formed. When the sandwiching step, the transfer step, and the separation step are repeated in this manner, the mold surface is appropriately dissolved by the mold dissolving component. As a result, the mold surface dissolves and the surface shape (fine concavo-convex structure) changes with the manufacture of the light-transmitting film. It can be formed on the surface of a film.
Therefore, if it is this invention, the light transmissive film which has the fine concavo-convex structure from which a height differs in the surface from a single mold can be manufactured continuously. Thus, for example, a light transmissive film having a fine concavo-convex structure in which the balance between antireflection performance and scratch resistance is changed according to the use of the light transmissive film can be efficiently produced from a single mold. There is no need to prepare a plurality of molds having different structure heights.

  In particular, the mold surface dissolution rate can be controlled by adjusting the mold dissolution component content and bleed-out amount in the curable composition, or by using a phosphate ester compound with an adjusted reduction rate in condition (a). Therefore, as shown in FIG. 4, the cured resin layer is formed so that a fine concavo-convex structure having a uniform height is formed in a certain region, and a fine concavo-convex structure in which the height continuously decreases in each constant region. Can be formed on the substrate film surface.

<Other embodiments>
The manufacturing method of the light transmissive film of this invention is not limited to the method mentioned above. In the method described above, the manufacturing apparatus shown in FIG. 2 is used to manufacture the light transmissive film 40 by irradiating the base film 42 with active energy rays. For example, the base film supported by the support film is used. The light transmissive film may be manufactured as follows.
That is, as shown in FIG. 5, the curable composition 38 is supplied between the surface of the base film 42 supported from the back surface side by the support film 48 and the roll-shaped mold 20, and cured through the support film 48. The active composition 38 is irradiated with active energy rays to produce a light transmissive film 40 in which a cured resin layer 44 having a fine concavo-convex structure is formed on the surface of the base film 42. The light transmissive film 40 thus obtained is supported by the support film 48, and the support film 48 is peeled off from the light transmissive film 40 as necessary.
The support film 48 is not particularly limited as long as it is a peelable film, and examples thereof include a PET film and a polycarbonate film.
The support film 48 may be a single layer film or a multilayer film.

  Moreover, although the method mentioned above is the method using the optical nanoimprint method, you may use the thermal nanoimprint method. In this case, instead of the curable composition described above, a thermoplastic resin containing a mold-dissolving component is used, the mold is heated to a temperature at which the thermoplastic resin flows, and the inverted structure of the mold is transferred to the cured resin layer. .

[Light transmissive film]
3 and 4 are cross-sectional views showing an example of the light transmissive film of the present invention. In addition, FIG. 3 is a figure which shows the fixed area | region part in the longitudinal direction of a film, and FIG. 4 is a figure which shows the transparent film manufactured continuously.
In the light transmissive film 40 shown in FIGS. 3 and 4, a cured resin layer 44 having a fine concavo-convex structure is formed on the surface of a base film 42.

  The base film 42 is a film having optical transparency. Examples of the material for the base film include an acrylic film, a PET film, a polycarbonate film, and a TAC film.

The cured resin layer 44 is a film made of a cured product of the curable composition described above, and has a fine uneven structure on the surface.
The fine concavo-convex structure on the surface of the light-transmitting film 40 when an anodized alumina mold is used is formed by transferring the fine concavo-convex structure on the surface of the anodized alumina, and is a cured product of the curable composition. A plurality of convex portions 46 are formed.

  As the fine concavo-convex structure, a so-called moth-eye structure in which a plurality of protrusions (convex portions) having a substantially conical shape or a pyramid shape are arranged is preferable. It is known that the moth-eye structure in which the distance between the protrusions is less than or equal to the wavelength of visible light is an effective anti-reflection measure by continuously increasing the refractive index from the refractive index of air to the refractive index of the material. It has been.

The average interval between the convex portions is not more than the wavelength of visible light, that is, not more than 400 nm. When the convex portions are formed using an anodized alumina mold, the average distance between the convex portions is about 100 to 200 nm, and is particularly preferably 250 nm or less.
Further, the average interval between the convex portions is preferably 20 nm or more from the viewpoint of easy formation of the convex portions.
The average interval between the convex portions is obtained by measuring 50 intervals between adjacent convex portions (distance from the center of the convex portion to the center of the adjacent convex portion) by electron microscope observation, and averaging these values. .

  In the light transmissive film of the present invention, it is preferable that the height of the fine concavo-convex structure continuously changes in the longitudinal direction of the film, and more preferably, as shown in FIG. It is preferable that the height continuously decreases for each predetermined region while a uniform fine uneven structure is formed. In particular, it is preferable that a fine uneven structure having a uniform height is formed in a region of 0.5 cm 2 or more, and more preferably a region of 1.0 cm 2 or more. The upper limit of the certain region is not particularly limited, and may be set according to the use of the light transmissive film.

The height of the convex portion is not particularly limited as long as it is different in the longitudinal direction F of the film. However, when the average interval between the convex portions is 100 nm, 80 to 500 nm is preferable, 120 to 400 nm is more preferable, and 150 to 300 nm. Is particularly preferred. If the height of the convex portion is 80 nm or more, the reflectance is sufficiently low and the wavelength dependency of the reflectance is small. If the height of a convex part is 500 nm or less, the scratch resistance of a convex part will become favorable.
The height of the convex portion is a value obtained by measuring the distance between the topmost portion of the convex portion and the bottommost portion of the concave portion existing between the convex portions when observed with an electron microscope at a magnification of 30000 times.

  Moreover, 0.8-5.0 are preferable, as for the aspect ratio (height of a convex part / average interval between convex parts) of a convex part, 1.2-4.0 are more preferable, and 1.5-3. 0 is particularly preferred. If the aspect ratio of the convex portion is 0.8 or more, the reflectance is sufficiently low. If the aspect ratio of the convex portion is 5.0 or less, the scratch resistance of the convex portion is good.

The shape of the convex part is a shape in which the convex sectional area in the direction perpendicular to the height direction continuously increases in the depth direction from the outermost surface, that is, the sectional shape in the height direction of the convex part is a triangle, trapezoid, A shape such as a bell shape is preferred.

  The difference between the refractive index of the cured resin layer 44 and the refractive index of the base film 42 is preferably 0.2 or less, more preferably 0.1 or less, and particularly preferably 0.05 or less. When the refractive index difference is 0.2 or less, reflection at the interface between the cured resin layer 44 and the base film 42 is suppressed.

  When the surface has a fine concavo-convex structure, if the surface is made of a hydrophobic material, super water repellency can be obtained by the lotus effect, and if the surface is made of a hydrophilic material, super hydrophilicity can be obtained. It is known that

  When the material of the cured resin layer 44 is hydrophobic, the water contact angle on the surface of the fine concavo-convex structure is preferably 90 ° or more, more preferably 110 ° or more, and particularly preferably 120 ° or more. If the water contact angle is 90 ° or more, water stains are less likely to adhere, so that sufficient antifouling properties are exhibited. Moreover, since water does not adhere easily, anti-icing can be expected.

  When the material of the cured resin layer 44 is hydrophilic, the water contact angle on the surface of the fine uneven structure is preferably 25 ° or less, more preferably 23 ° or less, and particularly preferably 21 ° or less. If the water contact angle is 25 ° or less, the dirt adhering to the surface is washed away with water and oil dirt is less likely to adhere, so that sufficient antifouling properties are exhibited. The water contact angle is preferably 3 ° or more from the viewpoint of suppressing the deformation of the fine concavo-convex structure due to water absorption of the cured resin layer 44 and the accompanying increase in reflectance.

<Effect>
The light-transmitting film of the present invention described above is obtained from a single mold, and the height of the fine concavo-convex structure is different in the longitudinal direction of the film. Therefore, the film suitable for various uses can be obtained from one film by cutting the light transmissive film of the present invention for each region having a height suitable for each use.

  Applications of light transmissive films include antireflective articles, antifogging articles, antifouling articles, water repellent articles, more specifically antireflection films for displays, automobile meter covers, automobile mirrors, automobile windows, organic or Examples include inorganic electroluminescence light extraction efficiency improving members, solar cell members, and the like.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto.

(Measurement of average interval and depth of mold pores)
A portion of the anodized alumina is shaved, platinum is deposited on the cross section for 1 minute, and a field emission scanning electron microscope (“JSM-7400F”, manufactured by JEOL Ltd.) is used at an acceleration voltage of 3.00 kV. The cross section was observed, and the average interval between the pores and the depth of the pores were measured. Each measurement was performed for 5 points, and the average value was obtained.

(Measurement of average distance and height of convex parts of light-transmitting film)
Platinum is deposited on the fracture surface of the light transmissive film for 10 minutes, and the cross section is observed under the condition of acceleration voltage: 3.00 kV using a field emission scanning electron microscope (“JSM-7400F” manufactured by JEOL Ltd.). Then, the average interval between the convex portions and the height of the convex portions were measured. Each measurement was performed for 5 points, and the average value was obtained.

(Measurement of reduction rate due to mold dissolution)
The immersion test was conducted by immersing the mold in a phosphate ester compound at 50 ° C. for 22 hours. After the immersion test, the mold was taken out and washed with acetone and chloroform. The mass of the mold before immersion and after cleaning was measured, and the reduction rate was obtained from the following formula. Further, the cleaned mold was observed with a scanning electron microscope.
Reduction rate (%) = {(Mass of mold before immersion−Mass of mold after washing) / Mass of mold before immersion} × 100

(Compatibility evaluation of mold melting component and polymerizable compound: measurement of transmittance)
A spectrophotometer U-3300 (Co., Ltd.) was prepared by adding 3 parts by mass of a mold-dissolving component to 100 parts by mass of a polymerizable compound mixture and stirring the mixture, and filling the quartz cell with the reference as an empty quartz cell. Hitachi, Ltd.) was used to measure the transmittance under conditions of a wavelength of 200 to 800 nm and a scan speed of 300 nm / min.

(Measurement of reflectance)
For a light-transmitting film in which the surface on which the fine uneven structure is not formed is painted black, using a spectrophotometer (“U-4100”, manufactured by Hitachi, Ltd.), a wavelength of 380 nm under the condition of an incident angle of 5 °. The relative reflectance between ˜780 nm was measured.

(Mold production)
After forging a 99.9% pure aluminum ingot, applying a blanket polishing treatment to a cylindrical aluminum prototype with a diameter of 200 mm and a length of 350 mm, and an average crystal grain size without rolling marks: 40 μm Then, this was electropolished in a perchloric acid / ethanol mixed solution (volume ratio: 1/4) and mirror-finished and used as an aluminum substrate.
Step (a):
The aluminum prototype was anodized in a 0.3 M oxalic acid aqueous solution for 30 minutes under conditions of a direct current of 40 V and a temperature of 16 ° C.
Step (b):
The aluminum prototype on which the oxide film having a thickness of 3 μm was formed was immersed in a 6% by mass phosphoric acid / 1.8% by mass chromic acid mixed aqueous solution for 2 hours to remove the oxide film.
Step (c):
The aluminum prototype was anodized for 30 seconds in a 0.3 M oxalic acid aqueous solution under the conditions of a direct current of 40 V and a temperature of 16 ° C.
Step (d):
The aluminum prototype 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 carry out pore size expansion treatment.
Step (e):
The step (c) and the step (d) are repeated a total of 5 times, and a roll-shaped mold body having anodized alumina having substantially conical pores with an average interval of 100 nm and a depth of 160 nm formed on the surface is provided. Obtained.

Step (f):
The phosphoric acid aqueous solution on the surface of the mold main body was gently washed away using a shower, and then the mold main body was immersed in running water for 10 minutes.
Step (g):
Air was blown from the air gun to the mold body to remove water droplets adhering to the surface of the mold body.
Step (h):
The mold body was immersed for 10 minutes at room temperature in a solution obtained by diluting OPTOOL DSX (manufactured by Daikin Chemicals Sales Co., Ltd.) to 0.1% by mass with a diluent HD-ZV (manufactured by Harves Co., Ltd.). Step (i):
The mold body was slowly pulled up from the diluted solution at 3 mm / second.
Step (j):
The mold body was air-dried overnight to obtain a mold treated with a release agent.

A scanning electron microscope image of the obtained mold is shown in FIG.
For evaluation of mold solubility, an aluminum plate (purity 99.99%) having a size of 50 mm × 50 mm × thickness 0.3 mm was used as the aluminum base material, and the ones implemented up to the step (c) were used.

[Example 1]
<Preparation of curable composition>
As a polymerizable compound, 20 parts by mass of polyethylene glycol diacrylate (“Aronix M260” manufactured by Toa Gosei Co., Ltd.) and a condensation reaction product of trimethylolethane / acrylic acid / succinic anhydride (manufactured by Osaka Organic Chemical Industry Co., Ltd., “TAS”) “) 70 parts by mass, 3 parts by mass of hydroxyethyl acrylate (Osaka Organic Chemical Co., Ltd.) and 7 parts by mass of methyl acrylate (Mitsubishi Chemical Co., Ltd.) were mixed to prepare a mixed solution.
In this mixed solution, 1.0 part by mass of 1-hydroxycyclohexyl-phenylketone (manufactured by Ciba Specialty Chemicals Co., Ltd., “IRGACURE184”) as a polymerization initiator and bis (2,4,6-trimethylbenzoyl) -phenyl 0.1 parts by mass of phosphine oxide (manufactured by Ciba Specialty Chemicals Co., Ltd., IRGACURE819), 0.3 parts by mass of a phosphoric acid ester compound (manufactured by Accel Corp., “INT-1856”) as a mold dissolving component, and an ultraviolet absorber (Kyodo Pharmaceutical Co., Ltd., “Viosorb110”) was added in an amount of 0.2 parts by mass to prepare a curable composition.
In addition, about the phosphate ester compound used as a mold melt | dissolution component, it was 0.41% when the reduction rate by mold melt | dissolution was measured.
Furthermore, in order to investigate the compatibility of the polymerizable compound of the mold-dissolving component, the transmittance at 500 nm of the mixed liquid obtained by adding 3 parts by mass of INT-1856 to 100 parts by mass of the mixed liquid of the polymerizable compound was measured. The transmittance was 47%, and the result was that the compatibility between the internal mold release agent and the polymerizable compound was poor and bleeding was easy.

<Manufacture of light transmissive film>
Using the production apparatus shown in FIG. 4, a light transmissive film was produced as follows.
As the roll-shaped mold 20, the previously produced mold was used.
As the base film 42, an acrylic film (manufactured by Mitsubishi Rayon Co., Ltd., “Acryprene HBS010”, thickness: 100 μm) is used. On the back surface thereof, a PET film with an adhesive as a support film 48 (manufactured by Sanei Kaken Co., Ltd. SAT-116T ", thickness: 38 [mu] m).

The curable composition 38 is transferred from the tank 22 between the roll-shaped mold 20 and the belt-shaped base film 42 supported from the back side by the belt-shaped support film 48 that moves along the surface of the roll-shaped mold 20. Supplied.
Next, the active energy ray irradiation device 28 installed below the roll-shaped mold 20 irradiates the curable composition 38 from the support film 48 side through the base film 42 with ultraviolet light having an accumulated light amount of 800 mJ / cm 2, and is curable. By curing the composition 38, the cured resin layer 44 to which the fine uneven structure on the surface of the roll-shaped mold 20 was transferred was formed.
By peeling the base film 42 having the cured resin layer 44 formed on the surface thereof from the roll-shaped mold 20 together with the support film 48 by the release roll 30, the light transmissive film 40 supported by the support film 48 was obtained.

As a result, a 10,000 m light transmissive film could be produced continuously and stably.
In the obtained light-transmitting film, the average distance between convex portions in the vicinity of 900 m after the start of production was 100 nm, the height of the convex portions was 160 nm, and the reflectance at a wavelength of 550 nm was 0.1%. It was.
The average interval between the convex portions near 2700 m was 100 nm, the height of the convex portions was 130 nm, and the reflectance at a wavelength of 550 nm was 0.2%.
The average interval between the convex portions in the vicinity at 4500 m was 100 nm, the height of the convex portions was 100 nm, and the reflectance at a wavelength of 550 nm was 0.4%.
The average interval between the convex portions near 6300 m was 100 nm, the height of the convex portions was 95 nm, and the reflectance at a wavelength of 550 nm was 0.8%.
The average interval between the protrusions near 7200 m was 100 nm, the height of the protrusions was 90 nm, and the reflectance at a wavelength of 550 nm was 1.2%.
The average interval between the convex portions near 10000 m was 100 nm, the height of the convex portions was 70 nm, and the reflectance at a wavelength of 550 nm was 2.6%.
In addition, within 1 cm 2 in each of the measured vicinity, spots with a height of the convex portion exceeding 10 nm and a reflectance exceeding 0.5% were not confirmed.

  From the above results, in the case of Example 1, the light having the fine concavo-convex structure on the surface, in which the fine concavo-convex structure having a uniform height is formed in the constant region, and the height continuously decreases in each constant region. A permeable film could be produced from a single mold.

[Comparative Example 1]
As a polymerizable compound, a condensation reaction product of trimethylolethane / acrylic acid / succinic anhydride (manufactured by Osaka Organic Chemical Industry Co., Ltd., “TAS”) 45 parts by mass, 1,6-hexanediol diacrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) ) And 10 parts by mass of radical polymerizable silicone oil (X-22-1602, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed to prepare a mixed solution.
In this mixed solution, 3.0 parts by mass of 1-hydroxycyclohexyl-phenylketone (manufactured by Ciba Specialty Chemicals Co., Ltd., “IRGACURE184”) as a polymerization initiator and bis (2,4,6-trimethylbenzoyl) -phenyl 0.2 parts by mass of phosphine oxide (manufactured by Ciba Specialty Chemicals, IRGACURE 819) and 0.1 parts by mass of a phosphoric acid ester compound (manufactured by Axel, “INT-1856”) as a mold dissolving component, A curable composition was prepared.
Further, the transmittance at 500 nm of a mixture obtained by adding 3 parts by mass of INT-1856 to 100 parts by mass of the mixture of polymerizable compounds and stirring the mixture was measured, and the transmittance was 95%. Therefore, the compatibility between the mold-dissolving component and the polymerizable compound was good, and the result that bleeding was difficult was obtained.

A light-transmissive film having a thickness of 10,000 m was produced in the same manner as in Example 1 except that the obtained curable composition was used.
As a result, from the start of production to 10000 m, the average period between the protrusions is 100 nm, the height of the protrusions is 150 nm, and the reflectance at a wavelength of 550 nm is 0.1%, neither of which has changed. It was.
From the above results, in the case of Comparative Example 1, the content of the phosphate ester compound in the curable composition was small, and further, the amount of bleedout of the phosphate ester compound was small, so that the mold surface did not dissolve. It is done. Therefore, it was not possible to produce a light transmissive film having a fine concavo-convex structure with different heights on the surface from a single mold.

14 Anodized alumina 20 Roll mold 38 Active energy ray curable composition 40 Light transmissive film 42 Base film 44 Cured resin layer F Longitudinal direction

Claims (7)

A method for producing a light-transmitting film in which a cured resin layer having a fine concavo-convex structure is formed on the surface of a base film,
A sandwiching step of sandwiching a fine concavo-convex structure raw material containing a mold melting component between a mold having a reverse structure of the fine concavo-convex structure on the surface and a base film,
By heating the fine concavo-convex structure raw material and / or curing the fine concavo-convex structure raw material by irradiating active energy rays, a cured resin layer to which the inverted structure of the mold is transferred is formed on the base film surface. A transfer process to obtain a light transmissive film;
A separation step of separating the obtained light transmissive film and the mold,
While repeating the sandwiching step, the transfer step, and the separation step, the cured resin layer to which the inverted structure of the mold is transferred is formed on the surface of the base film so that a fine uneven structure having a different height is formed in the longitudinal direction of the film. A method for producing a light transmissive film.   The cured resin layer to which the reversal structure of the mold is transferred is formed so that a fine uneven structure whose height continuously changes in the longitudinal direction of the film is formed while repeating the sandwiching process, the transfer process, and the separation process. The manufacturing method of the light transmissive film of Claim 1 formed in the base film surface.   The method for producing a light transmissive film according to claim 1, wherein the inverted structure of the fine concavo-convex structure on the mold surface is made of anodized alumina. The manufacturing method of the light transmissive film as described in any one of Claims 1-3 whose said mold melt | dissolution component is a phosphate ester compound which satisfy | fills the following conditions (a).
Condition (a): The mold mass after dipping the mold in a phosphoric acid ester compound at 50 ° C. for 22 hours is reduced by 0.01% or more compared with that before dipping. The manufacturing method of the light transmissive film of Claim 4 whose said phosphate ester compound is a polyoxyethylene alkyl phosphate ester compound represented by following formula (1).

[In Formula (1), R1 is an alkyl group, m is 1-20, and n is 1-3. ] A light-transmitting film in which a cured resin layer having a fine concavo-convex structure is formed on the surface of a base film,
The fine uneven structure is formed by transferring the fine uneven structure on the mold surface,
A light transmissive film in which the height of the fine concavo-convex structure is different in the longitudinal direction of the film.   The light transmissive film according to claim 6, wherein a height of the fine concavo-convex structure continuously changes in a longitudinal direction of the film.