CN110885469A

CN110885469A - Antifouling film and polymerizable composition

Info

Publication number: CN110885469A
Application number: CN201910832094.1A
Authority: CN
Inventors: 芝井康博; 田口登喜生
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2018-09-05
Filing date: 2019-09-04
Publication date: 2020-03-17
Also published as: JP2020038324A

Abstract

The invention provides an antifouling film which can maintain high antifouling property even if the film is continuously produced for a long time. The antifouling film of the present invention comprises: a substrate; and a polymer layer disposed on the surface of the substrate and having a concavo-convex structure in which a plurality of convex portions are provided at a pitch equal to or less than the wavelength of visible light, wherein the polymer layer is a cured product of a polymerizable composition containing, in terms of active ingredients, 2.5 to 12.5 wt% of a fluorine-based oligomer having a (meth) acryloyl group and 1 to 10 wt% of a block copolymer including a fluorine segment and a non-fluorine segment, and the fluorine-based oligomer is at least one of a perfluoropolyether-based oligomer and a perfluoroalkyl-based oligomer.

Description

Antifouling film and polymerizable composition

Technical Field

The present invention relates to a stain resistant film and a polymerizable composition.

Background

Various studies have been made on optical films having antireflection properties (for example, see patent documents 1 to 3). In particular, an optical film having a nano-sized uneven structure (nanostructure) is known to have excellent antireflection properties. According to such an uneven structure, since the refractive index changes continuously from the air layer to the base material, reflected light can be reduced significantly.

Documents of the prior art

Patent document

Patent document 1: japanese unexamined patent publication No. 9-145903

Patent document 2: japanese laid-open patent publication No. 2007-178724

Patent document 3: japanese laid-open patent publication No. 2018-59047

Disclosure of Invention

Problems to be solved by the invention

However, although such an optical film has excellent antireflection properties, on the other hand, due to the uneven structure of the surface thereof, when dirt such as fingerprints (sebum) adheres, the adhered dirt tends to spread, and it may be difficult to wipe off dirt that has entered between the convex portions. In addition, the attached dirt is easily visible because its reflectance is greatly different from that of the optical film. Therefore, a functional film (antifouling film) having a nano-sized uneven structure on the surface and excellent in dirt-wiping properties (e.g., fingerprint-wiping properties), i.e., antifouling properties, has been required.

In view of the above, the present inventors have studied and found that when a fluorine-based compound is added as a constituent component to a polymer layer constituting an uneven structure of an optical film, the antifouling property is improved.

However, the inventors of the present invention have further studied and found that when a mold is used for forming the uneven structure of the polymer layer, the mold releasability of the mold tends to decrease with an increase in the number of times of transfer of the mold, and as a result, the stain-proofing property of the resulting stain-proofing film tends to decrease.

As described above, conventionally, there has been a problem of realizing an antifouling film which can maintain a high antifouling property even when continuously produced for a long time. However, a solution to the above problem has not yet been found. For example, patent documents 1 to 3 do not describe reduction in the stain-proofing property of a stain-proofing film due to long-term continuous production, and do not solve the above-mentioned problems.

The present invention has been made in view of the above-mentioned situation, and an object thereof is to provide a stain-resistant film capable of maintaining high stain resistance even in continuous production for a long period of time, and a polymeric composition capable of forming a polymer layer of the stain-resistant film.

Means for solving the problems

One aspect of the present invention may be an antifouling film comprising: a substrate; and a polymer layer disposed on the surface of the substrate and having a concavo-convex structure in which a plurality of convex portions are provided at a pitch equal to or less than the wavelength of visible light, wherein the polymer layer is a cured product of a polymerizable composition containing, in terms of active ingredients, 2.5 to 12.5 wt% of a fluorine-based oligomer having a (meth) acryloyl group and 1 to 10 wt% of a block copolymer including a fluorine segment and a non-fluorine segment, the fluorine-based oligomer including at least one of a perfluoropolyether-based oligomer and a perfluoroalkyl-based oligomer.

Another aspect of the present invention may be a polymerizable composition containing, in terms of active ingredients, 2.5 to 12.5 wt% of a fluorine-based oligomer having a (meth) acryloyl group, the fluorine-based oligomer including at least one of a perfluoropolyether-based oligomer and a perfluoroalkyl-based oligomer, and 1 to 10 wt% of a block copolymer including a fluorine segment and a non-fluorine segment.

Effects of the invention

The present invention provides a stain-resistant film which can maintain a high stain resistance even when continuously produced for a long period of time, and a polymerizable composition which can form a polymer layer of the stain-resistant film.

Drawings

Fig. 1 is a schematic cross-sectional view showing an antifouling film according to an embodiment.

Fig. 2 is a schematic perspective view illustrating the polymer layer of fig. 1.

Fig. 3 is a schematic view showing the form of the fluorine-based compound present on the surface of the polymer layer in fig. 1.

Fig. 4A is a schematic cross-sectional view for explaining an example of the method for producing the antifouling film according to the embodiment.

Fig. 4B is a schematic cross-sectional view for explaining an example of the method for producing the antifouling film according to the embodiment.

Fig. 4C is a schematic cross-sectional view for explaining an example of the method for producing the antifouling film according to the embodiment.

Fig. 4D is a schematic cross-sectional view for explaining an example of the method for producing the antifouling film according to the embodiment.

Fig. 4E is a schematic cross-sectional view for explaining an example of the method for producing the antifouling film according to the embodiment.

Description of the reference numerals

1: antifouling film

2: base material

3: polymer layer

4: convex part

5: die set

6: polymerizable composition

7: mold release agent

10: fluorine-based oligomer (R)

20: block copolymer (S)

21: fluorine segment

22: non-fluorine segments

P: pitch of the convex part

H: height of the convex part

T: the thickness of the polymer layer.

Detailed Description

The present invention will be described in more detail below with reference to the accompanying drawings by way of examples, but the present invention is not limited to these examples. The configurations of the embodiments may be appropriately combined or modified within a range not departing from the gist of the present invention.

In the present specification, "X to Y" mean "X or more and Y or less".

[ embodiment ]

The antifouling film of the embodiment is described below. Fig. 1 is a schematic cross-sectional view showing an antifouling film according to an embodiment. Fig. 2 is a schematic perspective view illustrating the polymer layer of fig. 1.

The antifouling film 1 has a base material 2 and a polymer layer 3 disposed on the surface of the base material 2.

< substrate >

Examples of the material of the substrate 2 include resins such as triacetyl cellulose (TAC), polyethylene terephthalate (PET), and Methyl Methacrylate (MMA). The base material 2 may contain additives such as a plasticizer in addition to the above materials.

The surface of the substrate 2 (the surface on the polymer layer 3 side) may be subjected to an easy-adhesion treatment (e.g., undercoating treatment), and for example, a triacetyl cellulose film subjected to an easy-adhesion treatment can be used. The surface of the substrate 2 (the surface on the polymer layer 3 side) may be subjected to saponification treatment, and for example, a saponified triacetyl cellulose film may be used.

In the case where the antifouling film 1 is attached to a display device (for example, a liquid crystal display device) having a polarizing plate, the base material 2 may constitute a part of the polarizing plate.

From the viewpoint of ensuring transparency and workability, the thickness of the substrate 2 is preferably 50 to 100 μm.

< Polymer layer >

The polymer layer 3 has an uneven structure in which a plurality of convex portions (protrusions) 4 are provided at a pitch P (distance between apexes of adjacent convex portions 4) of 780nm or less of the wavelength of visible light, that is, a moth-eye structure (eye-shaped structure of moth). Therefore, the stain-resistant film 1 can exhibit excellent antireflection properties (low reflectance) based on the moth-eye structure.

The thickness T of the polymer layer 3 is preferably small from the viewpoint of allowing fluorine atoms in a fluorine-based compound to be incorporated into a polymerizable composition described later to be biased at a high concentration on the surface (surface on the opposite side from the substrate 2) of the polymer layer 3. Specifically, the thickness T of the polymer layer 3 is preferably 5 to 20 μm, and more preferably 8 to 12 μm.

Examples of the shape of the plurality of convex portions 4 include a shape (bell shape) including a columnar lower portion and a hemispherical upper portion, a shape (cone shape ) tapered toward the tip (cone shape), and the like. In fig. 1, the bottom side of the gap between adjacent projections 4 is inclined, but may be horizontal instead of inclined.

From the viewpoint of sufficiently preventing the occurrence of optical phenomena such as moire and rainbow unevenness, the average pitch of the plurality of projections 4 is preferably 100 to 400nm, more preferably 100 to 200 nm. The average pitch of the plurality of projections 4 is specifically an average value of pitches (P in fig. 1) of all adjacent projections in a region of 1 μm square in a plan photograph taken with a scanning electron microscope.

From the viewpoint of satisfying a preferable average aspect ratio of the plurality of projections 4 described later, the average height of the plurality of projections 4 is preferably 50 to 600nm, and more preferably 100 to 300 nm. The average height of the plurality of projections 4 is specifically an average value of the heights (H in fig. 1) of 10 projections arranged in series in a cross-sectional photograph taken with a scanning electron microscope. However, when 10 convex portions are selected, the convex portions having a portion where a defect or deformation occurs (a portion where a deformation occurs when a measurement sample is prepared, or the like) are excluded.

The average aspect ratio of the plurality of projections 4 is preferably 0.8 to 1.5, more preferably 1.0 to 1.3. When the average aspect ratio of the plurality of protrusions 4 is less than 0.8, the occurrence of optical phenomena such as moire and rainbow unevenness cannot be sufficiently prevented, and thus an excellent antireflection property may not be obtained. When the average aspect ratio of the plurality of convex portions 4 is larger than 1.5, the workability of the concave-convex structure is lowered, blocking may occur, or the transfer state at the time of forming the concave-convex structure may be deteriorated (the mold 5 described later may be clogged or entangled). The average aspect ratio of the plurality of projections 4 is a ratio (height/pitch) of the average height of the plurality of projections 4 to the average pitch.

The plurality of projections 4 may be arranged randomly or periodically (regularly). When the plurality of projections 4 are arranged periodically, unnecessary diffracted light may be generated due to the periodicity, and therefore, it is preferable that the plurality of projections 4 are arranged randomly as shown in fig. 2.

The polymer layer 3 is a cured product of the polymerizable composition. Examples of the polymer layer 3 include a cured product of an active energy ray-curable polymerizable composition, a cured product of a thermosetting polymerizable composition, and the like. In the present specification, the "active energy ray" refers to ultraviolet rays, visible rays, infrared rays, plasma, and the like. The polymer layer 3 is preferably a cured product of an active energy ray-curable polymerizable composition, and more preferably a cured product of an ultraviolet ray-curable polymerizable composition.

The polymerizable composition constituting the polymer layer 3 contains the following fluorine-based compound: a fluorine-based oligomer (R) having a (meth) acryloyl group; and a block copolymer (S) comprising a fluorine segment (segment) and a non-fluorine segment. In the present specification, "(meth) acryloyl" means acryloyl or methacryloyl.

(fluorine-containing oligomer (R))

The fluorine-based oligomer (R) has a (meth) acryloyl group, for example, a structure in which a (meth) acryloyl group is disposed at the terminal of a fluorine-containing hydrocarbon chain. In the fluorine-based oligomer (R), the (meth) acryloyl group functions as a polymerizable functional group that reacts with other components by external energy such as light or heat.

Since the fluorine-based oligomer (R) is blended in the polymerizable composition, fluorine atoms derived from the fluorocarbon chain are offset to the surface of the polymer layer 3 (the surface on the opposite side from the base material 2), and the surface free energy of the polymer layer 3 is reduced, so that the antifouling property of the antifouling film 1 is improved. On the other hand, the fluorine-based oligomer having no (meth) acryloyl group does not crosslink in the polymerizable composition, and therefore the stain-proofing property of the stain-proofing film 1 cannot be maintained for a long time.

The polymerizable composition contains 2.5 to 12.5 wt% of the fluorine-based oligomer (R), preferably 5 to 10 wt% of the fluorine-based oligomer (R) in terms of the active ingredient. When the content of the fluorine-based oligomer (R) in the polymerizable composition is less than 2.5% by weight in terms of active ingredient, the amount of fluorine atoms offset from the surface of the polymer layer 3 (the surface on the side opposite to the base material 2) is reduced, and the antifouling property of the antifouling film 1 is reduced. If the content of the fluorine-based oligomer (R) in the polymerizable composition is more than 12.5% by weight in terms of active ingredient, the compatibility with other components in the polymerizable composition is lowered, and as a result, the transparency of the stain-resistant film 1 (polymer layer 3) is lowered (whitened). When the polymerizable composition contains a plurality of fluorine-containing oligomers (R), the total content of the plurality of fluorine-containing oligomers (R) may be 2.5 to 12.5% by weight in terms of the active ingredient. In the present specification, the "active ingredient" of the polymerizable composition means a component which becomes a constituent of the polymer layer after curing, and a component (for example, a solvent) which does not contribute to the curing reaction (polymerization reaction) is excluded.

The fluorine-based oligomer (R) includes at least one of a perfluoropolyether-based oligomer (R1) and a perfluoroalkyl-based oligomer (R2). In the present specification, "perfluoropolyether oligomer" refers to a fluorine oligomer having a perfluoropolyether group. In the present specification, "perfluoroalkyl oligomer" refers to a fluorine oligomer having a perfluoroalkyl group. In particular, when the perfluoropolyether oligomer (R1) that is the fluorine oligomer (R) is blended, the smoothness of the surface (the surface on the side opposite to the substrate 2) of the polymer layer 3 is easily improved due to the easy mobility thereof, and as a result, the abrasion resistance is easily improved.

Known examples of the perfluoropolyether oligomer (R1) include Fomblin (registered trademark) MT70, Fluorolink (registered trademark) AD1700, Fluorolink MD700, KY-1203E, KY-1211, KY-1207, available from shin-Etsu chemical industries, and Optool DAC-HP, available from Dajin industries, available from Sorvey.

Known examples of the perfluoroalkyl oligomer (R2) include "Megafac (registered trademark) RS-90", "Megafac RS-75", "Megafac RS-76-NS" manufactured by DIC, "Ebecryl (registered trademark) 8110" manufactured by Daicel-Allnex, and "Ftergent (registered trademark) 601ADH 2" manufactured by Neos.

(Block copolymer (S))

The block copolymer (S) is a copolymer comprising a fluorine segment and a non-fluorine segment. In the present specification, the "fluorine segment" refers to a cured product (polymer) of a monomer containing a fluorine-based monomer as a main component. The fluorine-based monomer is not particularly limited as long as it is a monomer capable of radical polymerization containing a fluorine atom. In the present specification, the "non-fluorine segment" refers to a cured product (polymer) of a monomer containing a non-fluorine-based monomer as a main component. The non-fluorine-containing monomer is not particularly limited as long as it is a monomer capable of radical polymerization without containing a fluorine atom.

The proportion of the fluorine segment in the block copolymer (S) is preferably 10 to 90% by weight, more preferably 35 to 65% by weight. When the proportion of the fluorine segment in the block copolymer (S) is less than 10% by weight, the performance as the fluorine segment, that is, antifouling property (for example, water repellency and oil repellency) may not be sufficiently obtained. When the proportion of the fluorine segment in the block copolymer (S) is more than 90% by weight, the compatibility with other components in the polymerizable composition is lowered, and as a result, the transparency of the antifouling film 1 (polymer layer 3) may be lowered (whitened).

The number average molecular weight of the block copolymer (S) is preferably 5000 to 1000000, more preferably 10000 to 300000, and still more preferably 10000 to 100000. When the number average molecular weight of the block copolymer (S) is less than 5000, the fluorine segment becomes short, and the antifouling property (e.g., water repellency and oil repellency) which is the performance thereof may not be sufficiently obtained. When the number average molecular weight of the block copolymer (S) is more than 1000000, the compatibility with other components in the polymerizable composition is lowered, and as a result, the transparency of the stain-resistant film 1 (polymer layer 3) may be lowered (whitened).

Since the block copolymer (S) is blended in the polymerizable composition, the non-fluorine segment functions as a compatible segment having compatibility with other components in the polymerizable composition, while the fluorine segment (fluorine atom derived from the fluorine segment) is offset to the surface of the polymer layer 3 (surface on the side opposite to the substrate 2). Therefore, the surface free energy of the polymer layer 3 is reduced, and the antifouling property of the antifouling film 1 is improved.

The block copolymer (S) is preferably a perfluoroalkyl copolymer. In the present specification, the term "perfluoroalkyl copolymer" refers to a fluorine copolymer having a perfluoroalkyl group. In the case where the block copolymer (S) is a perfluoroalkyl copolymer, the fluorine segments are likely to be offset from the surface of the polymer layer 3 (the surface on the side opposite to the base material 2) (are likely to be arranged so that rigid molecular chains stand up), and therefore the fluorine atoms are likely to be densely distributed on the surface of the polymer layer 3 (the surface on the side opposite to the base material 2), and as a result, the antifouling property of the antifouling film 1 is likely to be improved.

The block copolymer (S) may not have a (meth) acryloyl group which functions as a polymerizable functional group. Since the non-fluorine segment of the block copolymer (S) has compatibility with other components in the polymerizable composition, it is easily fixed in the polymer layer 3 even if it does not have a (meth) acryloyl group as a polymerizable functional group.

The polymerizable composition contains 1 to 10 wt% of the block copolymer (S), preferably 3 to 8 wt% of the block copolymer (S), in terms of the active ingredient. When the content of the block copolymer (S) in the polymerizable composition is less than 1% by weight in terms of active ingredient, the amount of fluorine atoms offset from the surface of the polymer layer 3 (the surface on the opposite side to the base material 2) is reduced, and the antifouling property of the antifouling film 1 is reduced. When the content of the block copolymer (S) in the polymerizable composition is more than 10% by weight in terms of active ingredient, the compatibility with other components in the polymerizable composition is lowered, and as a result, the transparency of the stain-resistant film 1 (polymer layer 3) is lowered (whitened). When the polymerizable composition contains a plurality of block copolymers (S), the total content of the plurality of block copolymers (S) may be 1 to 10% by weight in terms of the active ingredient.

Examples of known block copolymers (S) include "Modiper (registered trademark) F606", "Modiper F206", and "Modiper F3636" manufactured by japan oil corporation.

In the present embodiment, since the fluorine-based oligomer (R) and the block copolymer (S) are used together as the fluorine-based compound, fluorine atoms are more biased to the surface of the polymer layer 3 (the surface on the opposite side from the base material 2), and the antifouling property of the antifouling film 1 is significantly improved. The inventors of the present invention considered that the mechanism of such improvement in the stain-proofing property of the stain-proofing film 1 is as follows.

Fig. 3 is a schematic view showing the form of the fluorine-based compound present on the surface of the polymer layer in fig. 1. As shown in fig. 3, the fluorine-based oligomer (R)10 is a soft segment, and is arranged so as to extend along the surface (surface on the opposite side of the base material 2) of the polymer layer 3 (so that the molecular chain falls). On the other hand, since the block copolymer (S)20 is a hard segment, the fluorine segment 21 is arranged closer to the surface of the polymer layer 3 (the surface on the opposite side from the substrate 2) than the non-fluorine segment 22 (arranged such that the molecular chain stands up). In this state, the block copolymer (S)20 is arranged between the fluorine-based oligomers (R)10, and thus fluorine atoms are densely distributed on the surface (surface on the opposite side to the base material 2) of the polymer layer 3, and therefore, for example, the antifouling property of the antifouling film 1 is significantly improved as compared with the case where only the fluorine-based oligomers (R)10 or the block copolymer (S)20 is used.

The polymerizable composition may further contain a monofunctional amide monomer. In the present specification, "monofunctional amide monomer" means a monomer having an amide group and 1 acryloyl group per 1 molecule. When the monofunctional amide monomer is blended in the polymerizable composition, the compatibility with the fluorine-based compound is improved, and therefore, fluorine atoms in the fluorine-based compound are likely to be biased to the surface of the polymer layer 3 (the surface on the opposite side from the base material 2), and the antifouling property of the antifouling film 1 is further improved. In addition, the shrinkage of the polymerizable composition during curing can be suppressed, and the cohesive force with the base material 2 can be improved, so that the adhesion between the polymer layer 3 and the base material 2 is improved.

The polymerizable composition preferably contains 1 to 15 wt% of the monofunctional amide monomer, more preferably 5 to 10 wt% of the monofunctional amide monomer, in terms of the active ingredient. When the content of the monofunctional amide monomer in the polymerizable composition is less than 1% by weight in terms of the active ingredient, the adhesion between the polymer layer 3 and the substrate 2 may not be sufficiently improved. When the content of the monofunctional amide monomer in the polymerizable composition is more than 15% by weight in terms of the active ingredient, the crosslinking density of the polymer layer 3 is not increased, and as a result, the abrasion resistance may be lowered. When the polymerizable composition contains a plurality of monofunctional amide monomers, the total content of the plurality of monofunctional amide monomers is preferably within the above range in terms of the active ingredient.

Examples of the monofunctional amide monomer include N-acryloylmorpholine, N-dimethylacrylamide, N-diethylacrylamide, N- (2-hydroxyethyl) acrylamide, diacetone acrylamide, N-N-butoxymethylacrylamide, and the like.

Examples of known N-acryloylmorpholine include "ACMO (registered trademark)" manufactured by KJ Chemicals, Inc. Examples of known N, N-dimethylacrylamide include "DMAA (registered trademark)" manufactured by KJ CHEMICALS corporation. Examples of known N, N-diethylacrylamide include "DEAA (registered trademark)" manufactured by KJ Chemicals corporation. Examples of known N- (2-hydroxyethyl) acrylamide include "HEAA (registered trademark)" manufactured by KJ CHEMICALS, Inc. Examples of the diacetone acrylamide include "DAAM (registered trademark)" manufactured by japan chemical company. Examples of known N-N-butoxymethylacrylamide include "NBMA" manufactured by MRC Unitech corporation.

The polymerizable composition may further contain a polyfunctional acrylate. In the present specification, "polyfunctional acrylate" means an acrylate having 2 or more acryloyl groups per 1 molecule. When a polyfunctional acrylate is blended in the polymerizable composition, the crosslinking density of the polymer layer 3 is increased, and appropriate elasticity (hardness) is imparted, so that the abrasion resistance is improved.

Preferably, the multifunctional acrylate comprises at least one multifunctional acrylate having an oxirane group. This imparts appropriate elasticity (hardness) to the polymer layer 3, thereby further improving the abrasion resistance.

The polymerizable composition may preferably contain 50 to 96 wt% of the polyfunctional acrylate, more preferably 60 to 90 wt% of the polyfunctional acrylate, in terms of the active ingredient. When the content of the polyfunctional acrylate in the polymerizable composition is less than 50% by weight in terms of the active ingredient, the polymer layer 3 is hardened, and as a result, the abrasion resistance may be lowered. When the content of the polyfunctional acrylate in the polymerizable composition is more than 96% by weight in terms of the active ingredient, the crosslinking density of the polymer layer 3 is not increased, and as a result, the abrasion resistance may be lowered. When the polymerizable composition contains a plurality of kinds of polyfunctional acrylates, the total content of the plurality of kinds of polyfunctional acrylates is preferably within the above range in terms of the effective component.

Examples of the polyfunctional acrylate include polyethylene glycol (200) diacrylate and trimethylolpropane triacrylate.

Examples of known polyethylene glycol (200) diacrylate include "MIRAMER (registered trademark) M282" manufactured by MIWON corporation. Examples of the trimethylolpropane triacrylate include "MIRAMER M300" manufactured by MIWON corporation.

The polymerizable composition may further contain a polymerization initiator. When a polymerization initiator is added to the polymerizable composition, the curability of the polymerizable composition is improved.

Examples of the polymerization initiator include a photopolymerization initiator and a thermal polymerization initiator, and among them, a photopolymerization initiator is preferable. The photopolymerization initiator is a polymerization initiator that is active against active energy rays.

Examples of the photopolymerization initiator include a radical polymerization initiator, an anionic polymerization initiator, and a cationic polymerization initiator. Examples of such photopolymerization initiators include acetophenones such as p-tert-butyltrichloroacetophenone, 2' -diethoxyacetophenone, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; ketones such as benzophenone, 4' -bisdimethylaminobenzophenone, 2-chlorothioxanthone, 2-methylthioxanthone, 2-ethylthioxanthone and 2-isopropylthioxanthone; benzoin ethers such as benzoin, benzoin methyl ether, benzoin isopropyl ether, and benzoin isobutyl ether; benzyl ketals such as benzyl dimethyl ketal and hydroxycyclohexyl phenyl ketone; acylphosphine oxides such as 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide and bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide; and alkylbenzophenones such as 1-hydroxy-cyclohexyl-phenyl-ketone.

Examples of known 2,4, 6-trimethylbenzoyl-diphenyl-phosphine oxide include "LUCIRIN (registered trademark) TPO" and "IRGACURE (registered trademark) TPO" manufactured by IGM Resins, Inc. Examples of the known bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide include "IRGACURE 819" manufactured by IGM Resins, inc. Examples of known 1-hydroxy-cyclohexyl-phenyl-ketone compounds include "IRGACURE 184" manufactured by IGM Resins, Inc.

The polymerizable composition may further contain a solvent. In this case, the solvent may be contained in each component of the polymerizable composition together with the active ingredient, or may be contained independently of each component.

Examples of the solvent include alcohols (having 1 to 10 carbon atoms, e.g., methanol, ethanol, n-or isopropanol, n-or tert-butanol, benzyl alcohol, octanol, etc.), ketones (having 3 to 8 carbon atoms, e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, dibutyl ketone, cyclohexanone, etc.), esters or ether esters (having 4 to 10 carbon atoms, e.g., ethyl acetate, butyl acetate, ethyl lactate, etc.), γ -butyrolactone, ethylene glycol monomethyl acetate, propylene glycol monomethyl acetate, ethers (having 4 to 10 carbon atoms, e.g., EG monomethyl ether (methyl cellosolve), EG monoethyl ether (ethyl cellosolve), diethylene glycol monobutyl ether (butyl cellosolve), propylene glycol monomethyl ether, etc.), aromatic hydrocarbons (having 6 to 10 carbon atoms, e.g., benzene, toluene, xylene, etc.), amides (having 3 to 10 carbon atoms, e.g., dimethylformamide, dimethylacetamide, N-methylpyrrolidone, etc.), halogenated hydrocarbons (carbon number 1 to 2: for example, methylene chloride, dichloroethane, etc.), petroleum solvents (for example, petroleum ether, naphtha, etc.), and the like.

From the viewpoint of stain resistance, the contact angle of water is preferably 120 ° or more, the contact angle of hexadecane is 30 ° or more, more preferably 140 ° or more, the contact angle of hexadecane is 70 ° or more, still more preferably 150 ° or more, and the contact angle of hexadecane is 90 ° or more, with respect to the surface of the polymer layer 3 (the surface on the side opposite to the base material 2).

The application of the antifouling film 1 is not particularly limited as long as it utilizes the excellent antifouling property, and for example, it may be an optical film application such as an antireflection film. Such an antireflection film is attached to the inside or outside of the display device, and thus contributes to improvement of visibility.

The antifouling property of the antifouling film 1 may mean that the dirt attached to the surface of the polymer layer 3 (the surface on the opposite side to the base material 2) can be easily removed, or that the dirt is not easily attached to the surface of the polymer layer 3 (the surface on the opposite side to the base material 2). Further, according to the stain-resistant film 1, the effect of the moth-eye structure can provide higher stain resistance than a conventional stain-resistant film (for example, a fluorine-containing film) having a normal surface such as a flat surface.

The antifouling film 1 can be produced by the following production method, for example. Fig. 4A, 4B, 4C, 4D, and 4E are schematic cross-sectional views for explaining an example of the method for producing the antifouling film according to the embodiment.

(A) Mold release treatment of mold

As shown in fig. 4A, a mold release agent 7 is applied to the surface of the mold 5.

Examples of the method of applying the release agent 7 include a method of applying by a spray coating method, a gravure printing method, a slit die method, a bar coating method, a potting (potting) method, and the like.

(B) Application of polymerizable composition

As shown in fig. 4B, the polymerizable composition 6 is applied to the surface of the base material 2.

Examples of the method of applying the polymerizable composition 6 include a method of applying by a spray coating method, a gravure printing method, a slot die method, a bar coating method, and the like. Among them, a method of coating by a gravure printing method or a slit die method is preferable from the viewpoint of making the film thickness uniform and improving productivity.

The polymerizable composition 6 contains the fluorine-containing oligomer (R) and the block copolymer (S) as the fluorine-containing compound at the above-mentioned predetermined ratio. Here, when the polymerizable composition 6 further contains a solvent, a heating treatment (drying treatment) for removing the solvent may be performed after the application of the polymerizable composition 6. The heat treatment is preferably performed at a temperature of the boiling point of the solvent or higher.

The above (a) and (B) may be performed at the same timing or at different timings.

(C) Formation of relief structure

The base material 2 is pressed against the surface of the mold 5 to which the release treatment agent 7 is applied, with the polymerizable composition 6 interposed therebetween. As a result, as shown in fig. 4C, an uneven structure is formed on the surface (the surface on the opposite side from the substrate 2) of the polymerizable composition 6.

(D) Formation of polymer layer

The polymerizable composition 6 is cured. As a result, as shown in fig. 4D, the polymer layer 3 is formed.

Examples of the method for curing the polymerizable composition 6 include irradiation with active energy rays, heating, and the like. The curing of the polymerizable composition 6 is preferably performed by irradiation with active energy rays, and more preferably by irradiation with ultraviolet rays. The irradiation with the active energy ray may be performed from the side of the substrate 2 of the polymerizable composition 6, or may be performed from the side of the mold 5 of the polymerizable composition 6. The number of irradiation of the polymerizable composition 6 with the active energy ray may be only 1 time, or may be plural times.

The above (C) and (D) may be performed at the same timing or at different timings.

(E) Stripping of the mold

As shown in fig. 4E, the mold 5 is peeled off from the polymer layer 3. As a result, the antifouling film 1 is completed.

In the present specification, the series of steps such as the above (B) to (E) is also referred to as "mold transfer". In the present production method example, when the antifouling film 1 is continuously produced, the above (a) may be performed at least 1 time in the first stage (before the 1 st transfer), and then the above (B) to (E) may be repeated. For example, the above (a) may not be performed every time the transfer is performed for the 2 nd and subsequent transfers as in the order of (a), (B), (C), (D), (E), and …. Further, as in the order of (a), (B), (C), (D), (E), (a), (B), (C), (D), (E), and …, (a) may be appropriately performed at the time of the 2 nd and subsequent transfers (at the time of the 3 rd transfer in this example). In the transfer of the mold, for example, if the substrate 2 is formed into a roll shape, the above-described (B) to (E) can be continuously and efficiently performed.

< mold >

As the mold 5, for example, a mold manufactured by the following method can be used. First, aluminum, which is a material of the mold 5, is formed on the surface of the support base material by sputtering. Next, anodization and etching are alternately repeated on the aluminum layer after the film formation, whereby a negative mold (mold 5) having a moth-eye structure can be produced. At this time, the time for performing the anodic oxidation and the time for performing the etching are adjusted, whereby the uneven structure of the mold 5 can be changed.

Examples of the material of the supporting base include: glass; metals such as stainless steel and nickel; polyolefin resins such as polypropylene, polymethylpentene, and cyclic olefin polymers (typically, "ZEONOR (registered trademark)" manufactured by japanese ruisane corporation and "ARTON (registered trademark)" manufactured by JSR corporation, which are norbornene resins); a polycarbonate resin; resins such as polyethylene terephthalate, polyethylene naphthalate and triacetyl cellulose. In addition, instead of forming aluminum on the surface of the support base, a base made of aluminum may be used.

Examples of the shape of the mold 5 include a flat plate shape and a roll shape.

< mold release treating agent >

The release agent 7 is used for the purpose of releasing the surface of the mold 5. The mold release agent 7 improves the mold release property (e.g., hydrophobicity) of the mold 5, and the mold 5 can be easily peeled from the polymer layer 3. Further, since the surface free energy of the mold 5 is low, when the substrate 2 is pressed against the mold 5, the fluorine atoms in the fluorine-based compound blended in the polymerizable composition 6 can be uniformly distributed on the surface of the polymerizable composition 6 (the surface on the side opposite to the substrate 2). Further, the fluorine atoms can be prevented from being separated from the surface (the surface on the opposite side from the base material 2) of the polymerizable composition 6 before the polymerizable composition 6 is cured. As a result, in the antifouling film 1, the fluorine atoms can be uniformly distributed on the surface of the polymer layer 3 (the surface on the opposite side to the base material 2).

Examples of the release agent 7 include a fluorine-based release agent, a silicon-based release agent, and a phosphate-based release agent, and among them, a fluorine-based release agent is preferable. As the fluorine-based mold release agent, a perfluoropolyether-based mold release agent is preferably used, and known examples thereof include "Optool (registered trademark) DSX", "Optool ud 509", and "Optool AES 4" manufactured by seikagaku industries.

In the present manufacturing method example, the mold release property of the mold 5 may be reduced with an increase in the number of times of transfer of the mold 5. This is because the release agent 7 deteriorates or components in the polymerizable composition 6 adhere (accumulate) on the surface of the mold 5 (the surface coated with the release agent 7). When the mold release property of the mold 5 is lowered in this way, the stain-proofing property of the obtained stain-proofing film 1 is lowered as far as the conventional one. On the other hand, in the present embodiment, as already described with reference to fig. 3, the interaction between the fluorine-based oligomer (R) and the block copolymer (S) blended in the polymerizable composition 6 causes the fluorine atoms to be densely distributed on the surface of the polymer layer 3 (the surface on the side opposite to the base material 2), and therefore, even if the number of times of transfer of the mold 5 is increased (even if the mold is continuously manufactured for a long time), the stain-proofing property of the resulting stain-proofing film 1 can be maintained at a high level.

[ examples and comparative examples ]

The present invention will be described more specifically below with reference to examples and comparative examples, but the present invention is not limited to these examples.

In examples and comparative examples, materials used for producing antifouling films are as follows.

< substrate >

"TAC-TD 80U" manufactured by Fuji photo film company was used, and its thickness was 80 μm.

< mold >

A mold manufactured by the following method was used. First, aluminum, which is a material of a mold, was formed on a 10cm square glass substrate by a sputtering method. The thickness of the aluminum layer after film formation was 1.0. mu.m. Next, by alternately repeating anodization and etching of the aluminum layer after the film formation, an anodized layer having a plurality of minute holes (the distance between the bottom points of adjacent holes (recesses) is equal to or less than the wavelength of visible light) is formed. Specifically, by sequentially performing anodization, etching, anodization (5 times, 4 times), a plurality of minute holes (recesses) having a shape (tapered shape) tapered toward the inside of the aluminum layer are formed, and as a result, a mold having an uneven structure is obtained. The anodic oxidation was carried out using oxalic acid (concentration: 0.03% by weight) under conditions of a liquid temperature of 5 ℃ and an applied voltage of 80V. The time for 1 anodization was 25 seconds. The etching was carried out using phosphoric acid (concentration: 1mol/l) at a liquid temperature of 30 ℃. The time for 1 etching was set to 25 minutes. The mold was observed with a scanning electron microscope, and the depth of the concave portion was 290 nm.

< mold release treating agent >

"Optool DSX" manufactured by Dajin industries, Inc. was used, and the concentration of the effective ingredient was 0.1% by weight.

< polymerizable composition >

Polymerizable compositions A1 to A13 and B1 to B9 having the compositions (effective component amounts) shown in tables 1 to 5 were used. The outline of each component is as follows.

(perfluoropolyether oligomer (R1))

·“MT70”

"Fomblin MT 70" manufactured by Solvay "

The concentration of the effective components: 80% by weight

·“1203E”

"KY-1203E" manufactured by shin-Etsu chemical industries, Ltd "

The concentration of the effective components: 20% by weight

(perfluoroalkyl oligomer (R2))

·“RS-90”

"Megafac RS-90" manufactured by DIC corporation "

The concentration of the effective components: 10% by weight

·“E8110”

"Ebecryl 8110" manufactured by Daicel-Allnex corporation "

The concentration of the effective components: about 50% by weight

(Block copolymer (S))

·“F606”

Modiper F606 manufactured by Nichisu oil Co "

The concentration of the effective components: 100% by weight

Perfluoroalkyl group: has the advantages of

(meth) acryloyl group: does not have

(perfluoroalkyl monomer)

·“FAAC-6”

CHEMINOX FAAC-6 manufactured by Unimatec "

The concentration of the effective components: 100% by weight

(monofunctional amide monomer)

·“AC”

"ACMO" manufactured by KJ CHEMICALS corporation "

The concentration of the effective components: 100% by weight

(polyfunctional acrylate)

·“M282”

"MIRAMER M282" manufactured by MIWON Corp "

The concentration of the effective components: 100% by weight

Number of ethylene oxide groups: 4 per 1 molecule

·“M300”

"MIRAMER M300" manufactured by MIWON Corp "

The concentration of the effective components: 100% by weight

Number of ethylene oxide groups: 0 number of

(polymerization initiator)

·“TPO”

IRGACURE TPO manufactured by IGM Resins "

The concentration of the effective components: 100% by weight

[ Table 1]

[ Table 2]

[ Table 3]

[ Table 4]

[ Table 5]

The content ratios (in terms of effective components) of the respective components in the polymerizable compositions a1 to a13 and B1 to B9 are shown in tables 6 to 10.

[ Table 6]

[ Table 7]

[ Table 8]

[ Table 9]

[ Table 10]

< example 1 >

The antifouling film of example 1 was produced by the following method.

(A) Mold release treatment of mold

A mold release treatment agent is applied to the surface of the mold. The thickness of the release treatment agent was 5 nm. The contact angle (static contact angle) of water with respect to the surface of the mold to which the release treatment agent is applied is 160 ° or more.

(B) Application of polymerizable composition

The polymerizable composition a1 was applied to the surface of the substrate. The thickness of the polymerizable composition A1 was 35 μm.

(C) Formation of relief structure

The base material was pressed against the surface of the mold to which the release treatment agent was applied, with the polymerizable composition a1 being sandwiched therebetween. As a result, an uneven structure was formed on the surface (surface on the opposite side to the substrate) of the polymerizable composition a 1.

(D) Formation of polymer layer

The polymerizable composition A1 was irradiated with ultraviolet light from the substrate side (dose: 1J/cm)²) And allowed to cure. As a result, a polymer layer is formed.

(E) Stripping of the mold

The mold is peeled away from the polymer layer. As a result, the antifouling film was completed. The thickness of the polymer layer was 12 μm.

The surface specifications of the antifouling film are as follows.

Shape of the convex portion: suspended bell shape

Average pitch of convex portions: 200nm

Average height of convex portion: 200nm

Average aspect ratio of convex portion: 1.0

The surface specification of the antifouling film was evaluated by using a scanning electron microscope "S-4700" manufactured by hitachi high and new technologies. In addition, for evaluation, an osmium coating machine "Neoc-ST" manufactured by Meiwafosis was used, and Fuji film and osmium oxide VIII (thickness: 5nm) manufactured by Wako chemical industries were coated on the surface (surface on the opposite side of the base material) of the polymer layer.

Then, the mold transfer was repeated 500 times (the series of steps (B) to (E) above). Hereinafter, the case where the number of times of mold transfer is 1 st is referred to as "specification 1", the case where the number of times of mold transfer is 200 th is referred to as "specification 2", and the case where the number of times of mold transfer is 500 th is referred to as "specification 3". That is, the stain-resistant film obtained by the 1 st transfer of the mold is referred to as a "standard 1 stain-resistant film", the stain-resistant film obtained by the 200 th transfer of the mold is referred to as a "standard 2 stain-resistant film", and the stain-resistant film obtained by the 500 th transfer of the mold is referred to as a "standard 3 stain-resistant film".

< examples 2 to 13 and comparative examples 1 to 9 >

Antifouling films of each example were produced in the same manner as in example 1, except that the production conditions shown in tables 11 to 15 were changed.

[ evaluation ]

The following evaluations were made for each example. The results are shown in tables 11 to 15.

< transparency >

As the transparency, the transparency of the polymerizable composition was evaluated. Specifically, the polymerizable composition was placed in a transparent test tube, and the state was visually observed under an environment of an illuminance of 100lx (fluorescent lamp). The criteria for determination are as follows.

○ transparent or slightly cloudy.

△ little white turbidity, and no precipitate was observed even after leaving for 1 day.

X: turbid white, and a precipitate was observed after standing for 1 day.

Here, it is judged that the higher the transparency of the polymerizable composition is, the higher the compatibility of the respective components in the polymerizable composition is.

< anti-reflection >

As the antireflection property, the reflectance of the antifouling film was measured. Specifically, first, a black acrylic plate "Acrylite (registered trademark) EX-502" manufactured by mitsubishi corporation was attached to the surface of the antifouling film having a specification of 1 to 3, respectively, on the side opposite to the polymer layer of the base material through an optical adhesive layer. In the antifouling films of each specification, the surface of the polymer layer (the surface opposite to the base material) was irradiated with light from a C light source from an azimuth of a polar angle of 5 °, and the reflectance (normal reflectance, unit:%) at an incident angle of 5 ° was measured. The reflectance was measured in the wavelength region of 250 to 850nm using a spectrophotometer "V-560" manufactured by Japan Spectroscopy. In this evaluation, the reflectance (visual reflectance: Y value) at a wavelength of 750nm was used as an evaluation index of the antireflection property. The criteria for determination are as follows.

◎, the reflectivity is less than or equal to 0.1

○, reflectivity is less than or equal to 0.3 when the reflectivity is more than 0.1

△ the reflectivity is less than or equal to 0.5 when the reflectivity is more than 0.3

X: "reflectance" > 0.5

Here, the case of determination of ◎, ○, or △ was determined to be excellent in antireflection properties.

< antifouling Property >

As the antifouling property, the hydrophobic property, oil repellency, and fingerprint erasure property of the antifouling film were evaluated.

(hydrophobicity)

For each of the antifouling films having the specifications of 1 to 3, water (droplets of about 10 μ l) was dropped on the surface (surface on the opposite side to the base material) of the polymer layer, and the contact angle (static contact angle) after 1 second from dropping was measured. In tables 11 to 15, "no dripping" indicates a state where the contact angle is very large (for example, 160 ° or more) and the hydrophobicity is very high.

(oil repellency)

Hexadecane (about 10 μ l of a droplet) was dropped on the surface (surface on the opposite side to the base material) of each of the antifouling films having the specifications of 1 to 3, and the contact angle (static contact angle) after 1 second from dropping was measured.

The contact angle is an average value of contact angles at 3 sites measured by θ/2 method (θ/2 ═ arctan (h/r), θ: contact angle, r: radius of droplet, h: height of droplet) using a portable contact angle meter "PCA-1" manufactured by kyowa scientific corporation. Here, the measurement point of the 1 st site is selected from the central portion of the antifouling film, and the measurement points of the 2 nd site and the 3 rd site are selected from 2 points which are 20mm or more away from the measurement point of the 1 st site and are in positions point-symmetrical to each other with respect to the measurement point of the 1 st site.

(fingerprint erasability)

First, a black acrylic plate "acryl EX-502" manufactured by mitsubishi yang corporation was attached to the surface of the base material opposite to the polymer layer via an optical adhesive layer, for each of the antifouling films having the specifications of 1 to 3. Next, as a conceivable fingerprint substance, 0.1ml of an artificial stain solution manufactured by ituita corporation was immersed in "BEMCOT (registered trademark) S-2" manufactured by asahi chemical fiber corporation, and then attached to a finger wearing a rubber glove. Then, the surface of the polymer layer (the surface opposite to the base material) of the antifouling film of each specification was attached with a finger to an artificial staining solution, and after 10 minutes, the surface was wiped with "BEMCOTS-2" manufactured by asahi chemical fiber company for 10 cycles, and whether or not the artificial staining solution was wiped off was visually observed under an environment of an illuminance of 100lx (fluorescent lamp). The criteria for determination are as follows.

○ the artificially contaminated liquid was completely wiped off and no wiping residue was visible.

△ the artificially contaminated liquid was not noticeable, but a small amount of wiping residue was visible when illuminated with a fluorescent lamp.

X: the artificially contaminated liquid was not erased at all.

Here, the case where the fingerprint was judged to be ○ or △ was judged to be excellent in fingerprint erasability.

[ Table 11]

[ Table 12]

[ Table 13]

[ Table 14]

[ Table 15]

As shown in tables 11 to 13, in examples 1 to 13, even if the number of times of transfer of the mold was increased (even if the mold was continuously manufactured for a long time), the antifouling property of the antifouling film was maintained at a high level. In examples 1 to 13, even if the number of times of transfer of the mold was increased (even in the case of continuous production for a long period of time), the anti-reflection property of the anti-fouling film was still excellent.

On the other hand, as shown in tables 14 and 15, in comparative examples 1 to 9, if the number of times of transfer of the mold is increased, it is impossible to produce a stain-resistant film having excellent stain resistance.

In comparative example 1, since no fluorine-based compound was added to the polymerizable composition, the antifouling property of the antifouling film was low at the stage of standard 1. Further, if the number of times of mold transfer is increased, the mold is less likely to peel off from the polymer layer in the 50 th mold transfer, and the production of the antifouling film is difficult, and therefore, the subsequent evaluation is suspended.

In comparative example 2, the antifouling film whitens (the antireflection property is lowered) at the stage of standard 2. Therefore, the subsequent evaluation is suspended. The inventors of the present invention considered that the mechanism of whitening of the antifouling film was as follows. In comparative example 2, as the fluorine-based compound, in addition to the fluorine-based oligomer (R) (perfluoropolyether-based oligomer (R1)), a perfluoroalkyl-based monomer "FAAC-6" was blended in the polymerizable composition instead of the block copolymer (S). "FAAC-6" is a low molecule and therefore, when transferring to a mold, it migrates to the surface of the mold (the surface coated with a release agent) and accumulates in a polymerized state. When the number of times of transfer of the mold is increased in this state, a part of the polymer derived from "FAAC-6" accumulated on the surface of the mold is transferred to the surface of the polymer layer (the surface on the opposite side of the base material), and as a result, the antifouling film is whitened.

In comparative example 3, the antifouling film whitens (the antireflection property is lowered) at the stage of standard 2. Therefore, the subsequent evaluation is suspended. The inventors of the present invention considered that the mechanism of whitening of the antifouling film was the same as in comparative example 2.

In comparative example 4, since only the fluorine-based oligomer (R) (perfluoropolyether-based oligomer (R1)) was blended as the fluorine-based compound in the polymerizable composition, the antifouling property of the antifouling film was hardly improved, and when the number of times of transfer of the mold was increased, the antifouling property of the antifouling film was reduced.

In comparative example 5, since only the fluorine-based oligomer (R) (perfluoroalkyl oligomer (R2)) was added as the fluorine-based compound to the polymerizable composition, the stain-proofing property of the stain-proofing film was hardly improved, and when the number of transfers of the mold was increased, the stain-proofing property of the stain-proofing film was lowered.

In comparative example 6, since the content of the fluorine-based oligomer (R) (perfluoropolyether-based oligomer (R1)) in the polymerizable composition was higher than 12.5% by weight in terms of active ingredient, the compatibility with other components in the polymerizable composition was lowered, and the antifouling film was whitened at the stage of standard 1 (the antireflection property was lowered). Therefore, the subsequent evaluation is suspended.

In comparative example 7, the content of the fluorine-based oligomer (R) (perfluoropolyether-based oligomer (R1)) in the polymerizable composition was less than 2.5% by weight in terms of active ingredient, and therefore, when the number of transfers of the mold was increased, the stain-proofing property of the stain-proofing film was lowered.

In comparative example 8, since the content of the block copolymer (S) in the polymerizable composition was more than 10% by weight in terms of active ingredient, the compatibility with other components in the polymerizable composition was lowered, and the antifouling film was whitened at the stage of standard 1 (the antireflection property was lowered). Therefore, the subsequent evaluation is suspended.

In comparative example 9, the content of the block copolymer (S) in the polymerizable composition was less than 1% by weight in terms of active ingredient, and therefore, when the number of transfers of the mold was increased, the stain-proofing property of the stain-proofing film was lowered.

[ remarks ]

One aspect of the present invention may be an antifouling film comprising: a substrate; and a polymer layer disposed on the surface of the substrate and having a concavo-convex structure in which a plurality of convex portions are provided at a pitch equal to or less than the wavelength of visible light, wherein the polymer layer is a cured product of a polymerizable composition containing, in terms of active ingredients, 2.5 to 12.5 wt% of a fluorine-based oligomer having a (meth) acryloyl group and 1 to 10 wt% of a block copolymer including a fluorine segment and a non-fluorine segment, the fluorine-based oligomer including at least one of a perfluoropolyether-based oligomer and a perfluoroalkyl-based oligomer. According to this aspect, an antifouling film which can maintain high antifouling property even when continuously produced for a long period of time can be realized.

In one aspect of the present invention, the polymerizable composition may contain 5 to 10 wt% of the fluorine-based oligomer in terms of an active ingredient. This further improves the stain-proofing property of the stain-proofing film. Further, since the compatibility with other components in the polymerizable composition is improved, the transparency of the stain-resistant film (polymer layer) is further improved as a result.

In one aspect of the present invention, the polymerizable composition may contain 3 to 8 wt% of the block copolymer in terms of an active ingredient. This further improves the stain-proofing property of the stain-proofing film. Further, since the compatibility with other components in the polymerizable composition is improved, the transparency of the stain-resistant film (the polymer layer) is further improved as a result.

In one aspect of the present invention, the polymerizable composition may further contain a monofunctional amide monomer. This improves the compatibility with the fluorine-based compound containing the fluorine-based oligomer and the block copolymer, and hence fluorine atoms in the fluorine-based compound are likely to be displaced on the surface of the polymer layer (the surface on the opposite side from the base material), thereby further improving the antifouling property of the antifouling film. In addition, since the shrinkage of the polymerizable composition during curing can be suppressed and the cohesive force with the base material can be improved, the adhesion between the polymer layer and the base material can be improved.

In one aspect of the present invention, the polymer layer may have a thickness of 5 to 20 μm. Thus, the fluorine atoms in the fluorine-based compound including the fluorine-based oligomer and the block copolymer are biased at a higher concentration to the surface of the polymer layer (the surface on the opposite side from the base material).

In one aspect of the present invention, the average pitch of the plurality of projections may be 100 to 400 nm. This can sufficiently prevent the occurrence of optical phenomena such as moire and rainbow unevenness.

In one aspect of the present invention, the average height of the plurality of projections may be 50 to 600 nm. This makes it possible to achieve the desired average aspect ratio of the plurality of projections.

In one aspect of the present invention, an average aspect ratio of the plurality of projections may be 0.8 to 1.5. This can sufficiently prevent the occurrence of optical phenomena such as moire and rainbow unevenness, and can realize excellent antireflection properties. Further, the occurrence of blocking and the deterioration of the transfer state in forming the uneven structure, which are caused by the deterioration of the workability of the uneven structure, can be sufficiently prevented.

Another aspect of the present invention may be a polymerizable composition containing, in terms of active ingredients, 2.5 to 12.5 wt% of a fluorine-based oligomer having a (meth) acryloyl group, the fluorine-based oligomer including at least one of a perfluoropolyether-based oligomer and a perfluoroalkyl-based oligomer, and 1 to 10 wt% of a block copolymer including a fluorine segment and a non-fluorine segment. According to this aspect, a polymerizable composition capable of constituting the polymer layer of the stain-resistant film of one aspect of the present invention can be realized.

In another aspect of the present invention, the polymerizable composition may contain 5 to 10 wt% of the fluorine-based oligomer in terms of an active ingredient.

In another aspect of the present invention, the polymerizable composition may contain 3 to 8 wt% of the block copolymer in terms of an active ingredient.

In another aspect of the present invention, the polymerizable composition may further contain a monofunctional amide monomer.

Claims

1. An antifouling film comprising:

a substrate; and

a polymer layer disposed on the surface of the base material, the polymer layer having a concavo-convex structure in which a plurality of convex portions are provided at a pitch equal to or less than the wavelength of visible light on the surface, the antifouling film being characterized in that,

the polymer layer is a cured product of the polymerizable composition,

the polymerizable composition contains 2.5 to 12.5 wt% of a fluorine-based oligomer having a (meth) acryloyl group and 1 to 10 wt% of a block copolymer comprising a fluorine segment and a non-fluorine segment in terms of active ingredients,

the fluorine-based oligomer includes at least one of a perfluoropolyether-based oligomer and a perfluoroalkyl-based oligomer.

2. The antifouling film according to claim 1,

the polymerizable composition contains 5 to 10 wt% of the fluorine-based oligomer in terms of an active ingredient.

3. The antifouling film according to claim 1 or 2,

the polymerizable composition contains 3 to 8 wt% of the block copolymer in terms of active ingredient.

4. The antifouling film according to any one of claims 1 to 3,

the polymerizable composition further contains a monofunctional amide monomer.

5. The antifouling film according to any one of claims 1 to 4,

the polymer layer has a thickness of 5 to 20 μm.

6. The antifouling film according to any one of claims 1 to 5,

the average pitch of the plurality of projections is 100 to 400 nm.

7. The antifouling film according to any one of claims 1 to 6,

the average height of the plurality of projections is 50 to 600 nm.

8. The antifouling film according to any one of claims 1 to 7,

the average aspect ratio of the plurality of projections is 0.8 to 1.5.

9. A polymerizable composition characterized by containing, as a main component,

the fluorine-containing oligomer having a (meth) acryloyl group is contained in an amount of 2.5 to 12.5 wt% in terms of active ingredient, and the block copolymer includes a fluorine segment and a non-fluorine segment in an amount of 1 to 10 wt%,