KR20230118816A - optical film - Google Patents

Abstract

The optical film (F) of the present invention includes a composite film portion 100 including a transparent substrate 10 and an optical function layer 20 in this order, and an optical function layer 20 in the transparent substrate 10 and a pressure-sensitive adhesive layer 101 in contact with the opposite side. The peel strength X (N/25 mm) between the transparent base material 10 and the pressure-sensitive adhesive layer 101 and the water vapor transmission rate Y (g/m 2 24 h) of the composite film portion 100 are 26.6 X + Y ≥ 502 satisfies

Description

optical film

The present invention relates to an optical film.

A transparent optical film provided with a layer having a predetermined optical function (optical function layer) may be formed on the outer surface on the visual side of a display such as a liquid crystal display. As an optical film, an antireflection film, a transparent conductive film, an electromagnetic wave shielding film, etc. are mentioned. The optical film includes, for example, a transparent substrate, an optical function layer located on one side of the substrate, and an adhesive layer for sticking located on the other side of the transparent substrate. About the technology related to such an optical film, it describes, for example in patent document 1 below.

Japanese Unexamined Patent Publication No. 2011-145443

In an optical film, air bubbles may be formed at the interface between the transparent substrate and the pressure-sensitive adhesive layer depending on the storage environment and use environment after production. For example, bubbles large enough to be visually recognized may be formed in an optical film formed on an on-vehicle display and an outdoor display used under an environment with a high amount of ultraviolet irradiation. Formation of air bubbles in the optical film is undesirable because it may impair the appearance of the adherend on which the film is formed. Formation of air bubbles in the optical film formed on the surface of the display is undesirable because it may affect image display by the display.

The present invention provides an optical film suitable for suppressing the formation of air bubbles at the interface between a transparent substrate and an adhesive layer.

The present invention [1] is provided with a composite film portion comprising a transparent substrate and an optical function layer in this order, and an adhesive layer in contact with the opposite side of the optical function layer in the transparent substrate, wherein the transparent substrate and the above An optical film in which the peel strength X (N/25 mm) between the pressure-sensitive adhesive layers and the water vapor transmission rate Y (g/m 2 *24 h) of the composite film portion satisfy 26.6 X + Y ≥ 502.

This invention [2] includes the optical film as described in said [1] in which the said optical function layer is an antireflection layer.

This invention [3] includes the optical film described in [2] above, wherein the antireflection layer alternately includes a high refractive index layer having a relatively large refractive index and a low refractive index layer having a relatively small refractive index.

This invention [4] contains the optical film in any one of said [1]-[3] in which the said adhesive layer contains an acrylic polymer as a base polymer.

The present invention [5] includes the optical film according to any one of [1] to [4] above, wherein the transparent substrate is a triacetyl cellulose film.

The present invention [6] includes the optical film according to any one of [1] to [5], wherein the composite film part further includes a hard coat layer between the transparent substrate and the optical function layer.

This invention [7] includes the optical film as described in said [6] in which the said hard-coat layer contains metal oxide microparticles|fine-particles.

This invention [8] includes the optical film described in [7] above, wherein the metal oxide fine particles are nanosilica particles.

This invention [9] includes the optical film as described in any one of said [6]-[8] in which the surface by the side of the said optical function layer in the said hard-coat layer was corona-treated.

In the optical film of the present invention, the peel strength X (N/25 mm) between the transparent substrate and the pressure-sensitive adhesive layer and the moisture permeability Y (g/m 2 24 h) of the composite film portion satisfy 26.6 X + Y ≥ 502 , it is suitable for suppressing the formation of bubbles at the interface between the transparent substrate and the pressure-sensitive adhesive layer.

1 is a cross-sectional schematic diagram of an embodiment of an optical film of the present invention.
2 shows the peel strength (peel strength between the transparent substrate and the pressure-sensitive adhesive layer) and moisture permeability (water vapor permeability of the composite film portion) measured for each optical film of Examples 1 to 14 and Comparative Examples 1 to 10 as x-coordinate and y-coordinate represents a plot of

1 is a cross-sectional schematic diagram of an optical film (F) that is an embodiment of an optical film of the present invention. The optical film F is provided with a composite film portion 100 and an adhesive layer 101 sequentially in the thickness direction, and is an antireflection film in the present embodiment.

The composite film unit 100 includes at least a transparent substrate 10 and an optical function layer 20 . The transparent substrate 10 has a first surface 11 and a second surface 12 opposite to the first surface 11 . The optical function layer 20 is located on the side of the first surface 11 of the transparent substrate 10 . The pressure-sensitive adhesive layer 101 is in contact with the second surface 12 of the transparent substrate 10 (ie, the side opposite to the optical function layer 20 in the transparent substrate 10).

The composite film unit 100 includes a transparent substrate 10, a hard coat layer 31, an adhesive layer 32, an optical function layer 20, and an antifouling layer 33 toward one side in the thickness direction. You may provide in this order. Preferably, the composite film part 100 consists of the transparent substrate 10, the hard coat layer 31, the adhesive layer 32, the optical function layer 20, and the antifouling layer 33.

The transparent substrate 10 is, for example, a transparent resin film having flexibility. As the material of the resin film, a thermoplastic resin having both transparency and strength is preferably used. Examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, and acrylic resins. , norbornene resins, polyarylate resins, polystyrene resins, and polyvinyl alcohol resins. These thermoplastic resins may be used independently, or two or more types may be used together. The transparent substrate 10 is preferably a cellulose film, more preferably a triacetyl cellulose film, from the viewpoint of ensuring transparency and strength as well as moisture permeability.

The resin film may contain one type or two or more types of additives. As an additive, a ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring agent, a flame retardant, an antistatic agent, a pigment, and a coloring agent are mentioned, for example.

The thickness of the transparent substrate 10 is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 20 μm or more, from the viewpoint of strength. The thickness of the transparent substrate 10 is preferably 300 μm or less, more preferably 200 μm or less, from the viewpoint of handleability.

The visible light transmittance of the transparent substrate 10 is preferably 80% or more, more preferably 90% or more, from the viewpoint of transparency. The visible light transmittance of the transparent substrate 10 is, for example, 100% or less.

The hard coat layer 31 is an element for improving mechanical properties such as hardness in the optical function layer 20, for example. The hard coat layer 31 is located on the first surface 11 (one surface in the thickness direction) of the transparent substrate 10 . The hard coat layer 31 is a cured product of curable resin composition. Curable resin composition contains curable resin at least.

Examples of curable resins include polyester resins, acrylic resins, urethane resins, acrylic urethane resins, amide resins, silicone resins, epoxy resins, and melamine resins. These curable resins may be used independently, or two or more types may be used together. From the viewpoint of ensuring high hardness, as the curable resin, an acrylic urethane resin is preferably used.

Moreover, as a curable resin, an ultraviolet curable resin and a thermosetting resin are mentioned, for example, Since it can be hardened without heating at a high temperature, from a viewpoint of being useful for productivity improvement of the optical film (F), Preferably ultraviolet rays are used. A curable resin is used. The ultraviolet curable resin includes at least one selected from the group consisting of ultraviolet curable monomers, ultraviolet curable oligomers, and ultraviolet curable polymers.

The hard coat layer 31 is preferably a hard coat layer having anti-glare properties (anti-glare hard coat layer). The hard coat layer 31 as an anti-glare hard coat layer is a cured product of a curable resin composition containing a curable resin (matrix resin) and fine particles (anti-glare fine particles) for expressing anti-glare properties. Examples of the anti-glare fine particles include metal oxide fine particles and organic fine particles. Examples of the material of the metal oxide fine particles include silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Examples of materials for the organic fine particles include polymethyl methacrylate, polystyrene, polyurethane, acrylic-styrene copolymer, benzoguanamine, melamine, and polycarbonate. These microparticles|fine-particles may be used independently, and 2 or more types may be used together. From the viewpoint of expressing good anti-glare properties in the hard coat layer 31, nano-silica particles are preferably used as the anti-glare fine particles.

The average particle diameter of the fine particles is, for example, 10 μm or less, preferably 8 μm or less, and, for example, 1 nm or more. When nanoparticles are used as the fine particles, the average particle diameter of the fine particles is, for example, 100 nm or less, preferably 70 nm or less, and, for example, 1 nm or more. The average particle diameter of the fine particles is obtained as a D50 value (cumulative 50% median diameter) based on a particle size distribution obtained by, for example, a particle size distribution measurement method in a laser scattering method.

The refractive index of the matrix resin (after curing) is, for example, 1.46 or higher, preferably 1.49 or higher, more preferably 1.50 or higher, still more preferably 1.51 or higher. The refractive index is, for example, 1.60 or less, preferably 1.59 or less, more preferably 1.58 or less, still more preferably 1.57 or less.

The refractive index of the fine particles may be higher or lower than the refractive index of the matrix resin. When the refractive index of the fine particles is higher than that of the matrix resin, the refractive index of the fine particles is, for example, 1.62 or less, preferably 1.60 or less, more preferably 1.59 or less, still more preferably 1.50 or less. When the refractive index of the fine particles is lower than that of the matrix resin, the refractive index of the fine particles is, for example, 1.40 or higher, preferably 1.42 or higher, and more preferably 1.44 or higher.

The content of the fine particles in the hard coat layer 31 is preferably 1 part by mass or more, more preferably 3 parts by mass or more with respect to 100 parts by mass of the matrix resin. The content of the fine particles in the hard coat layer 31 is preferably 30 parts by mass or less, and more preferably 20 parts by mass or less with respect to 100 parts by mass of the matrix resin.

The thickness of the hard coat layer 31 is preferably 0.5 μm or more, more preferably 1 μm or more, from the viewpoint of securing the hardness of the copper layer. The thickness of the hard coat layer 31 is 10 micrometers or less, for example.

The surface on the side of the adhesion layer 32 in the hard coat layer 31 may be subjected to surface modification treatment. Examples of the surface modification treatment include plasma treatment, corona treatment, ozone treatment, primer treatment, gloss treatment, and coupling agent treatment. From the viewpoint of ensuring high adhesion between the hard coat layer 31 and the adhesion layer 32, the surface on the side of the adhesion layer 32 in the hard coat layer 31 (that is, the surface on the side of the optical function layer 20) ) is preferably corona treated.

The adhesive layer 32 is a layer for ensuring the adhesion between the transparent substrate 10 or, when the hard coat layer 31 is formed, the hard coat layer 31 and the optical function layer 20 . The adhesive layer 32 is located on one surface of the hard coat layer 31 in the thickness direction. Examples of the material of the adhesive layer 32 include metals such as silicon, nickel, chromium, aluminum, tin, gold, silver, platinum, zinc, titanium, tungsten, zirconium, indium, and palladium, and two types of these metals. The above alloys and oxides of these metals are exemplified. Coexistence of adhesion to both the organic layer (specifically, the transparent substrate 10 or the hard coat layer 31) and the oxide layer (specifically, the first high refractive index layer 21), and the transparency of the adhesive layer 32 From this point of view, as a material for the adhesive layer 32, silicon oxide (SiOx) or indium tin oxide (ITO) is preferably used. When silicon oxide is used as the material of the adhesive layer 32, SiOx having a smaller oxygen content than the stoichiometric composition is preferably used, and more preferably SiOx having an x of 1.2 or more and 1.9 or less is used.

The thickness of the adhesive layer 32 is, for example, 1 nm or more from the viewpoint of ensuring the adhesive force between the transparent substrate 10 and the optical function layer 20 and the transparency of the adhesive layer 32, and For example, it is 10 nm or less.

The optical function layer 20 is located on one surface of the adhesive layer 32 in the thickness direction. In the present embodiment, the optical function layer 20 has a high refractive index layer with a relatively large refractive index and a low refractive index layer with a relatively small refractive index alternately in the thickness direction as an antireflection layer for suppressing the reflected intensity of external light. . In the antireflection layer, the net intensity of the reflected light is attenuated by utilizing interference between reflected light at a plurality of interfaces in a plurality of thin layers (high refractive index layer and low refractive index layer) included therein. Further, in the antireflection layer, an interference effect of attenuating the reflected light intensity can be developed by adjusting the optical film thickness (product of refractive index and thickness) of each thin layer. In this embodiment, the optical function layer 20 as such an antireflection layer specifically includes the first high refractive index layer 21, the first low refractive index layer 22, and the second high refractive index layer 23 and the second low refractive index layer 24 in order toward one side in the thickness direction.

The first high refractive index layer 21 and the second high refractive index layer 23 are each made of a high refractive index material having a refractive index of preferably 1.9 or more at a wavelength of 550 nm. From the viewpoint of coexistence of high refractive index and low absorption of visible light, examples of the high refractive index material include niobium oxide (Nb ₂ O ₅ ), titanium oxide, zirconium oxide, tin-doped indium oxide (ITO), and antimony-doped tin oxide. (ATO), and niobium oxide is preferably used.

The optical film thickness (product of the refractive index and the thickness) of the first high refractive index layer 21 is, for example, 20 nm or more and, for example, 55 nm or less. The optical film thickness of the second high refractive index layer 23 is, for example, 60 nm or more and, for example, 330 nm or less.

The first low refractive index layer 22 and the second low refractive index layer 24 are each made of a low refractive index material having a refractive index of preferably 1.6 or less at a wavelength of 550 nm. From the viewpoint of coexistence of low refractive index and low absorption of visible light, as a low refractive index material, for example, silicon dioxide (SiO ₂ ) and magnesium fluoride, preferably silicon dioxide. As the material of the second low refractive index layer 24, silicon dioxide is preferably used also from the viewpoint of securing the adhesion between the second low refractive index layer 24 and the antifouling layer 33.

The optical film thickness of the first low refractive index layer 22 is, for example, 15 nm or more and, for example, 70 nm or less. The optical film thickness of the second low refractive index layer 24 is, for example, 100 nm or more and, for example, 160 nm or less.

In addition, in the optical function layer 20, the thickness of the first high refractive index layer 21 is, for example, 1 nm or more, preferably 5 nm or more, and, for example, 30 nm or less, preferably 20 nm or less. The thickness of the first low refractive index layer 22 is, for example, 10 nm or more, preferably 20 nm or more, and, for example, 50 nm or less, preferably 30 nm or less. The thickness of the second high refractive index layer 23 is, for example, 50 nm or more, preferably 80 nm or more, and, for example, 200 nm or less, preferably 150 nm or less. The thickness of the second low refractive index layer 24 is, for example, 60 nm or more, preferably 80 nm or more, and, for example, 150 nm or less, preferably 100 nm or less.

The antifouling layer 33 is a layer having an antifouling function in the optical film F, and is located on one surface of the optical function layer 20 in the thickness direction. The antifouling function of the antifouling layer 33 includes a function of suppressing adhesion of contaminants such as resin to the exposed surface of the optical film F (the surface on the opposite side to the pressure-sensitive adhesive layer 101), and adhered contamination. Features that make it easier to remove the substance are included.

As a material of the antifouling|fouling|fouling layer 33, the organic compound containing a fluorine group is mentioned, for example. As an organic compound containing a fluorine group, the alkoxysilane compound which has a perfluoro polyether group is mentioned, for example. As an alkoxysilane compound which has a perfluoropolyether group, the compound represented by the following general formula (1) is mentioned, for example.

R ¹ -R ² -O-(CH ₂ ) _m -Si(OR ³ ) ₃ (1)

In general formula (1), R ¹ represents a linear or branched fluoroalkyl group in which one or more hydrogen atoms in the alkyl group are substituted with fluorine atoms (carbon number is 1 or more and 20 or less), preferably Preferably, it represents a perfluoroalkyl group in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms.

R ² represents a structure containing at least one repeating structure of a perfluoropolyether (PFPE) group, preferably a structure containing two repeating structures of a PFPE group. Examples of the repeating structure of the PFPE group include a repeating structure of a linear PFPE group and a repeating structure of a branched PFPE group. As a repeating structure of the linear PFPE group, for example, a structure represented by -(OC _n F _2n ) _p - (n represents an integer of 1 or more and 20 or less, and p is an integer of 1 or more and 50 or less The same below) can be mentioned. Examples of the repeating structure of the branched PFPE group include a structure represented by -(OC(CF ₃ ) ₂ ) _p - and a structure represented by -(OCF ₂ CF(CF ₃ )CF ₂ ) _p -. can The repeating structure of the PFPE group is preferably a repeating structure of a linear PFPE group, more preferably -(OCF ₂ ) _p - and -(OC ₂ F ₄ ) _p -.

R ³ represents an alkyl group having 1 or more and 4 or less carbon atoms, preferably a methyl group.

m represents an integer of 1 or greater. In addition, m is preferably an integer of 20 or less, more preferably 10 or less, still more preferably 5 or less.

Among the alkoxysilane compounds having such a perfluoropolyether group, compounds represented by the following general formula (2) are preferably used.

CF _3- (OCF ₂ ) _q- (OC ₂ F ₄ ) _r -O-(CH ₂ ) ₃ -Si(OCH ₃ ) ₃ (2)

In general formula (2), q represents an integer of 1 or more and 50 or less, and r represents an integer of 1 or more and 50 or less.

As the alkoxysilane compound having a perfluoropolyether group, you may use a commercial item. As a commercially available product, for example, Optool UD509 (a compound represented by the above general formula (2), manufactured by Daikin Industry Co., Ltd.) is exemplified. Moreover, the alkoxysilane compound which has a perfluoropolyether group may be used independently, and 2 or more types may be used together.

The thickness of the antifouling layer 33 is preferably 1 nm or more, more preferably 2 nm or more, still more preferably 3 nm or more. The thickness of the antifouling layer 33 is preferably 100 nm or less, more preferably 50 nm or less, still more preferably 30 nm or less.

From the viewpoint of exhibiting high antifouling function in the antifouling layer 33, the pure contact angle of the antifouling layer 33 is preferably 100 degrees or more, more preferably 102 degrees or more, still more preferably 105 degrees or more. The pure contact angle is, for example, 120 degrees or less. The pure contact angle is obtained by forming a water droplet having a diameter of 2 mm or less on the surface of the antifouling layer 33 and measuring the contact angle of the water droplet with respect to the surface of the antifouling layer 33.

The pressure-sensitive adhesive layer 101 is a layer formed of a resin composition and has light transmission properties. The pressure-sensitive adhesive layer 101 is located on the other surface (second surface 12) of the transparent substrate 10 in the thickness direction. The resin composition contains at least a base polymer that causes the pressure-sensitive adhesive layer 101 to develop adhesiveness. Examples of the base polymer include acrylic polymers, rubber-based polymers, silicone-based polymers, urethane-based polymers, polyester-based polymers, and polyamide-based polymers. From the viewpoint of realizing both the adhesive strength and high transparency required for the pressure-sensitive adhesive layer of the optical film (F), an acrylic polymer is preferably used as the base polymer.

The acrylic polymer is a polymer containing the largest amount of monomer units derived from (meth)acrylic acid alkyl esters in mass ratio, and is obtained by polymerizing a monomer component containing, for example, (meth)acrylic acid alkyl esters in a proportion of 50% by mass or more. it is a polymer "(meth)acrylic acid" shall mean acrylic acid and/or methacrylic acid.

As an alkyl (meth)acrylate, the (meth)acrylic acid alkylester which has a linear or branched C1-C20 alkyl group is mentioned, for example. Examples of such alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, isopropyl (meth)acrylate, ( Isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, (meth)acrylate ) Heptyl acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, (meth)acrylic acid Isodecyl, undecyl (meth)acrylate, dodecyl (meth)acrylate, isotridodecyl (meth)acrylate, tetradecyl (meth)acrylate, isotetradecyl (meth)acrylate, pentadecyl (meth)acrylate, (meth)acrylate ) Hexadecyl acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isooctadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. (meth)acrylic-acid alkyl ester may be used independently, and 2 or more types may be used together. As the (meth)acrylic acid alkyl ester, an acrylic acid alkyl ester having an alkyl group of 2 to 8 carbon atoms is preferably used, and 2-ethylhexyl acrylate is more preferably used.

The ratio of the (meth)acrylic acid alkyl ester in the monomer component is preferably 55% by mass or more, more preferably 60% by mass or more, from the viewpoint of appropriately expressing basic properties such as adhesiveness in the pressure-sensitive adhesive layer (101). , More preferably, it is 65 mass % or more. Further, the ratio of the (meth)acrylic acid alkyl ester in the monomer component is preferably 90% by mass or less, more preferably 85% by mass or less, still more preferably 80% by mass or less.

The monomer component may contain one or two or more functional group-containing vinyl monomers copolymerizable with (meth)acrylic acid alkyl ester. The functional group-containing vinyl monomer is useful for modifying the acrylic polymer, such as securing the cohesive force of the acrylic polymer and introducing a crosslinking point into the acrylic polymer. The proportion of the functional group-containing vinyl monomer in the monomer component is, for example, 5% by mass or more, preferably 10% by mass or more, more preferably 15% by mass or more, still more preferably 20% by mass or more. The proportion of the functional group-containing vinyl monomer in the monomer component is preferably 45% by mass or less, more preferably 40% by mass or less, still more preferably 35% by mass or less.

Examples of the functional group-containing vinyl monomer include a hydroxyl group-containing vinyl monomer, a nitrogen atom-containing vinyl monomer, a carboxyl group-containing vinyl monomer, and an acid anhydride vinyl monomer. The functional group-containing vinyl monomer may be used alone or in combination of two or more.

Examples of the hydroxyl group-containing vinyl monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 3-hydroxypropyl (meth)acrylate. , (meth)acrylate 4-hydroxybutyl, (meth)acrylate 6-hydroxyhexyl, (meth)acrylate 8-hydroxyoctyl, (meth)acrylate 10-hydroxydecyl, (meth)acrylate 12-hydroxyl uryl, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate.

Examples of the nitrogen atom-containing vinyl monomer include N-vinyl cyclic amides. Examples of the N-vinyl cyclic amide include N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-morpholinone, and N-vinyl-2-caprolactam. , N-vinyl-1,3-oxazin-2-one, and N-vinyl-3,5-morpholinedione.

Examples of the carboxy group-containing vinyl monomer include acrylic acid, methacrylic acid, 2-carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

Examples of acid anhydride vinyl monomers include maleic anhydride and itaconic anhydride.

The pressure-sensitive adhesive composition may contain a polyfunctional (meth)acrylate as a copolymerizable crosslinking agent. Examples of the polyfunctional (meth)acrylate include 1,6-hexanedioldi(meth)acrylate, butanedioldi(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly) Propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethyl All-propane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl(meth)acrylate, and vinyl(meth)acrylate are mentioned. These polyfunctional (meth)acrylates may be used independently, or two or more types may be used together. In this embodiment, trimethylolpropane triacrylate is preferably used.

The content of the polyfunctional (meth)acrylate in the pressure-sensitive adhesive composition is preferably 0.01 part by mass or more, more preferably 0.02 part by mass or more, still more preferably 0.03 part by mass or more with respect to 100 parts by mass of the acrylic polymer. . The copper content is preferably 1 part by mass or less, more preferably 0.5 part by mass or less with respect to 100 parts by mass of the acrylic polymer.

The pressure-sensitive adhesive composition preferably contains a silane coupling agent. Examples of the silane coupling agent include γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, and N-phenyl-aminopropyltrimethoxysilane. Toxysilane may be mentioned, and γ-glycidoxypropyltrimethoxysilane is preferably used.

The content of the silane coupling agent in the pressure-sensitive adhesive composition is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, still more preferably 0.2 parts by mass or more with respect to 100 parts by mass of the acrylic polymer. The copper content is preferably 1 part by mass or less, more preferably 0.5 part by mass or less with respect to 100 parts by mass of the acrylic polymer. This structure regarding the content of the silane coupling agent is preferable for realizing high adhesiveness under humid conditions, particularly high adhesiveness to glass, in the pressure-sensitive adhesive layer 101 .

The pressure-sensitive adhesive composition preferably contains a photopolymerization initiator. A photoinitiator accelerates the crosslinking reaction of polyfunctional (meth)acrylate. As a photoinitiator, a photoradical initiator is mentioned, for example. Examples of the photoradical initiator include hydroxyketones such as 1-hydroxycyclohexylphenyl ketone, benzyldimethylketals, aminoketones, acylphosphine oxides, benzophenones, and triazine derivatives containing a trichloromethyl group. can be heard These photoinitiators may be used independently, or two or more types may be used together.

The content of the photopolymerization initiator in the pressure-sensitive adhesive composition is, for example, 0.01 part by mass or more, preferably 0.02 part by mass or more, more preferably 0.05 part by mass or more with respect to 100 parts by mass of the acrylic polymer. The copper content is, for example, 1 part by mass or less, and preferably 0.5 part by mass or less.

If necessary, the pressure-sensitive adhesive layer 101 further contains additives such as tackifying resins, anti-aging agents, fillers, colorants such as pigments and dyes, antioxidants, chain transfer agents, plasticizers, softeners, surfactants, and antistatic agents. You can do it.

The thickness of the pressure-sensitive adhesive layer 101 is preferably 5 μm or more, more preferably 10 μm or more, and still more preferably 15 μm, from the viewpoint of realizing sufficient adhesive force to the adherend in the optical film (F). More than that. From the viewpoint of ensuring transparency, the thickness of the pressure-sensitive adhesive layer 101 is preferably 300 μm or less, more preferably 200 μm or less, still more preferably 100 μm or less.

In the optical film (F), the peel strength X (N/25 mm) between the transparent substrate 10 and the pressure-sensitive adhesive layer 101, and the water vapor transmission rate Y (g/m 2 24 h) of the composite film portion 100 satisfies 26.6 X + Y ≥ 502, preferably 26.6 X + Y ≥ 527. Such a configuration is suitable for suppressing the formation of air bubbles at the interface between the transparent substrate 10 and the pressure-sensitive adhesive layer 101 . Specifically, it is as showing, for example, in Examples and Comparative Examples to be described later. Suppression of bubble formation in the optical film (F) is suitable for ensuring a good appearance in the adherend (G) (shown in FIG. 1 ) on which the optical film (F) is formed. Specifically, suppression of bubble formation in the optical film (F) formed on the outer surface on the visual side of a display such as a liquid crystal display is suitable for avoiding or reducing the effect on image display by the display. do.

The optical film F can be manufactured, for example, by bonding the composite film part 100 and the pressure-sensitive adhesive layer 101 together after producing the composite film part 100 and the pressure-sensitive adhesive layer 101, respectively. can

In the composite film unit 100, for example, in a roll-to-roll system, a hard coat layer 31, an adhesive layer 32, an optical function layer 20, and an antifouling layer 33 are formed on the transparent substrate 10 ) can be produced by sequentially stacking them. The optical function layer 20 includes a first high refractive index layer 21, a first low refractive index layer 22, a second high refractive index layer 23, and a second low refractive index layer 24 on the adhesive layer 32. ) can be formed by sequentially stacking.

The hard coat layer 31 is formed by applying a curable resin composition containing a curable resin and optionally anti-glare fine particles to the first surface 11 of the transparent substrate 10 to form a coating film, and then curing the coating film. can be formed by When the curable resin composition contains an ultraviolet curable resin, the coating film is cured by ultraviolet irradiation. When the curable resin composition contains a thermosetting resin, the coating film is cured by heating.

The exposed surface of the hard coat layer 31 formed on the transparent substrate 10 is subjected to surface modification treatment as needed. In the case of plasma treatment as a surface modification treatment, argon gas is used as an inert gas, for example. In addition, the discharge power in the plasma treatment is, for example, 100 W or more and, for example, 500 W or less.

The adhesive layer 32, the first high refractive index layer 21, the first low refractive index layer 22, the second high refractive index layer 23, and the second low refractive index layer 24 are formed by dry coating. It can be formed by forming a film. As a dry coating method, a sputtering method, a vacuum deposition method, and CVD are mentioned, for example, and sputtering method is used preferably.

In the sputtering method, a negative voltage is applied to a target disposed on a cathode while gas is introduced into the sputtering chamber under vacuum conditions. Thereby, a glow discharge is generated to ionize gas atoms, and the gas ions collide with the target surface at high speed to eject the target material from the target surface, and the protruding target material is deposited on a predetermined surface. In order to form a metal oxide layer, reactive sputtering is preferable from the viewpoint of film formation speed. In reactive sputtering, a metal target is used as a target, and a mixed gas of an inert gas such as argon and oxygen (reactive gas) is used as the gas described above. The ratio of oxygen contained in the metal oxide layer to be formed can be adjusted by adjusting the flow rate ratio (sccm) of the inert gas and oxygen.

As a power supply for implementing the sputtering method, a DC power supply, an AC power supply, an RF power supply, and an MFAC power supply (an AC power supply having a frequency band of several tens to hundreds of MHz) are exemplified. The discharge voltage in the sputtering method is, for example, 100 V or more and, for example, 1000 V or less. In addition, the film formation pressure in the sputtering chamber where the sputtering method is performed is, for example, 0.1 Pa or more and, for example, 1 Pa or less.

The antifouling layer 33 can be formed by forming a film of, for example, a fluorine group-containing organic compound on the optical function layer 20 . As a method for forming the antifouling layer 33, a wet coating method and a dry coating method are exemplified. As a wet coating method, the gravure coat method, the reverse coat method, and the die coat method are mentioned, for example. As a dry coating method, a vacuum deposition method, a sputtering method, and CVD are mentioned, for example, The vacuum deposition method is used preferably.

The pressure-sensitive adhesive layer 101 can be formed, for example, as follows. First, a monomer component for forming an acrylic polymer, a photopolymerization initiator, and other components added as necessary are mixed, and then the mixture is exposed to ultraviolet rays under a nitrogen atmosphere to partially cause a photopolymerization reaction. In this way, a solution (partial polymer solution) containing a partially polymerized monomer component is obtained. Next, at least a polyfunctional (meth)acrylate is added to this partial polymer solution, a silane coupling agent is added as needed, and these are mixed to obtain an acrylic pressure-sensitive adhesive composition. Next, on the first peeling liner, an acrylic pressure-sensitive adhesive composition is applied to form a coating film. Next, the exposed surface of the pressure-sensitive adhesive coating film on the first peeling liner is covered with the second peeling liner. Next, the pressure-sensitive adhesive coating film between the first and second peeling liners is cured by ultraviolet irradiation. In this way, the pressure-sensitive adhesive layer 101 coated on both sides with the release liner is obtained.

And after peeling the one-sided peeling liner from the obtained adhesive layer 101, the surface of the adhesive layer 101 exposed by this peeling is 2nd of the transparent base material 10 of the composite film part 100 mentioned above. By bonding with the surface 12, the optical film (F) can be manufactured.

The above-mentioned optical film (F) may be another optical film other than the antireflection film. As another optical film, a transparent conductive film and an electromagnetic wave shielding film are mentioned, for example.

When the optical film F is a transparent conductive film, the optical function layer 20 of the optical film F includes, for example, a first dielectric thin film, a transparent electrode film such as an ITO film, and a second dielectric film. It is provided sequentially in the thickness direction. In the optical function layer 20 having such a laminated structure, visible light transmittance and conductivity are compatible.

When the optical film F is an electromagnetic wave shielding film, the optical functional layer 20 of the optical film F includes, for example, a metal thin film having electromagnetic wave reflecting ability and a metal oxide film alternately in the thickness direction. In the optical functional layer 20 having such a laminated structure, both shielding against electromagnetic waves of a specific wavelength and visible light transmittance are compatible.

[Example]

The present invention will be described in detail by showing examples below, but the present invention is not limited to the examples. In addition, the specific numerical values such as the compounding amount (content), physical property values, and parameters described below are the compounding amounts (content), physical property values, and parameters corresponding to those described in the above-mentioned “Specific Content for Carrying Out the Invention”. etc., can be replaced with the upper limit (a numerical value defined as “below” or “less than”) or lower limit (a numerical value defined as “above” or “exceeding”).

[Example 1]

First, an acrylic monomer composition containing nano-silica particles (trade name "NC035", average primary particle diameter of nano-silica particles is 40 nm, solid content concentration is 50%, and the ratio of nano-silica particles in solid content is 60% by mass, manufactured by Arakawa Chemical Industry Co., Ltd.) Mixed composition M was obtained by mixing 67 parts by mass (in terms of solid content) and 33 parts by mass of an ultraviolet curable polyfunctional acrylate (trade name "binder A", solid content concentration: 100%, manufactured by Arakawa Chemical Industry Co., Ltd.). In the mixed composition M in this example, the amount of nano-silica particles relative to the total amount of 100 parts by mass of the acrylic resin component (acrylic monomer in "NC035" and polyfunctional acrylate in "binder A") and nano-silica particles was 40 mass It is wealth. Next, 100 parts by mass of this mixed composition M (in terms of solid content) and polymethyl methacrylate particles as anti-glare fine particles (trade name "Techpolymer", average particle diameter of 3 µm, refractive index of 1.525, manufactured by Sekisui Chemical Industry Co., Ltd.) 3 1.5 parts by mass of silicon particles as anti-glare fine particles (trade name "Toss Pearl 130", average particle diameter of 3 μm, refractive index of 1.42, manufactured by Momentive Performance Materials Japan Co., Ltd.), and thixotropy imparting agent (trade name " 1.5 parts by mass of "Lucentite SAN", a synthetic smectite that is an organic clay, manufactured by Corp Chemical Co., Ltd.), 3 parts by mass of a photopolymerization initiator (trade name "OMNIRAD907", manufactured by BASF), and a leveling agent (trade name "LE303", manufactured by Kyoeisha) Chemical company make) 0.15 mass part and toluene were mixed, and the composition (varnish) of 45 mass % of solid content concentration was prepared. For mixing, an ultrasonic disperser was used. Next, the composition was applied to one side of a triacetyl cellulose (TAC) film (thickness: 80 μm) as a transparent resin film to form a coating film. Next, after curing this coating film by ultraviolet irradiation, it was dried by heating. In the ultraviolet irradiation, a high-pressure mercury lamp was used as a light source, an ultraviolet ray with a wavelength of 365 nm was used, and the cumulative irradiation light amount was 200 mJ/cm 2 . In addition, the heating time was 60°C and the heating temperature was 60 seconds. Thus, an anti-glare hard coat (HC) layer having a thickness of 7 μm was formed on the TAC film.

Next, the HC layer surface of the HC layer-forming TAC film was subjected to plasma treatment in a vacuum atmosphere of 1.0 Pa by a roll-to-roll type plasma processing apparatus. In this plasma treatment, argon gas was used as an inert gas, and the discharge electric power was 300 W.

Next, an adhesion layer and an antireflection layer were sequentially formed on the HC layer of the HC layer-formed TAC film after plasma treatment (sputter film formation process). Specifically, an indium tin oxide (ITO) layer having a thickness of 1.5 nm as an adhesive layer and a first high refractive index layer as an adhesive layer are formed on the HC layer of the TAC film after plasma treatment by using a roll-to-roll sputter film formation apparatus. A Nb ₂ O ₅ layer with a thickness of 12 nm as the first low refractive index layer, a SiO ₂ layer with a thickness of 28 nm as the first low refractive index layer, a Nb ₂ O ₅ layer with a thickness of 100 nm as the second high refractive index layer, and a second low refractive index layer. SiO ₂ layers with a thickness of 85 nm were sequentially formed. In the formation of the adhesion layer, an ITO target was used, argon gas as an inert gas, and oxygen gas as a reactive gas of 10 parts by volume with respect to 100 parts by volume of the argon gas were used, the discharge voltage was set to 400 V, and the atmospheric pressure in the film formation chamber ( The film formation air pressure) was set to 0.2 Pa, and the ITO layer was formed by MFAC sputtering. In the formation of the first high refractive index layer, a Nb target was used, 100 parts by volume of argon gas and 5 parts by volume of oxygen gas were used, the discharge voltage was set to 415 V, the deposition atmospheric pressure was set to 0.42 Pa, and MFAC sputtering was performed. A Nb ₂ O ₅ layer was formed. In the formation of the first low refractive index layer, a Si target is used, 100 parts by volume of argon gas and 30 parts by volume of oxygen gas are used, the discharge voltage is set to 350 V, the deposition pressure is set to 0.3 Pa, and MFAC sputtering is performed. A SiO ₂ layer was deposited. In the formation of the second high refractive index layer, a Nb target was used, 100 parts by volume of argon gas and 13 parts by volume of oxygen gas were used, the discharge voltage was set to 460 V, the film formation atmospheric pressure was set to 0.5 Pa, and MFAC sputtering was performed. A Nb ₂ O ₅ layer was formed. In the formation of the second low refractive index layer, a Si target is used, 100 parts by volume of argon gas and 30 parts by volume of oxygen gas are used, the discharge voltage is set to 340 V, the deposition atmospheric pressure is set to 0.25 Pa, and MFAC sputtering is performed. A SiO ₂ layer was deposited. As described above, antireflection layers (a first high refractive index layer, a first low refractive index layer, a second high refractive index layer, and a second low refractive index layer) are laminated on the HC layer of the TAC film with an HC layer, with an adhesive layer interposed therebetween. formed.

Next, an antifouling layer was formed on the formed antireflection layer. Specifically, a predetermined alkoxysilane compound-containing solution (trade name "Optul UD509", an alkoxysilane compound containing a perfluoropolyether group represented by the above general formula (2), manufactured by Daikin Kogyo Co., Ltd.) is applied onto the antireflection layer, After forming the coating film, the coating film was dried at 60°C to form an antifouling layer having a thickness of 8 nm.

Next, an adhesive layer was formed on the exposed second surface (surface opposite to the HC layer) of the TAC film in which the above-described HC layer to the antifouling layer were laminated. Specifically, first, 67 parts by mass of 2-ethylhexyl acrylate (2EHA), 15 parts by mass of N-vinyl-2-pyrrolidone (NVP), 3 parts by mass of hydroxyethyl acrylate (HEA), 15 parts by mass of 4-hydroxybutyl acrylate (4HBA), 0.05 parts by mass of a first photopolymerization initiator (trade name "Irgacure 184", manufactured by BASF), and a second photopolymerization initiator (trade name "Irgacure 651") 」, manufactured by BASF) 0.05 part by mass was mixed in the reaction vessel. Next, by exposing the obtained mixture to ultraviolet rays in a nitrogen atmosphere, a photopolymerization reaction was caused to partially occur, and a solution containing a partial polymer having a polymerization rate of about 10% by mass (partial polymer solution) was obtained. Next, to this partial polymer solution, 5 parts by mass of acrylic polymer P (prepared as described later), 0.04 part by mass of trimethylolpropane triacrylate, and 0.3 part by mass of a silane couple with respect to 100 parts by mass of the partial polymer in the solution. A ring agent (trade name "KBM-403", γ-glycidoxypropyltrimethoxysilane, manufactured by Shin-Etsu Silicone Co., Ltd.) was added and mixed to obtain an acrylic adhesive composition. Next, an acrylic pressure-sensitive adhesive composition was applied onto the release-treated surface of a polyester film (first release liner) having a thickness of 38 μm, one side of which had been subjected to silicone release treatment, to form a coating film. Next, the exposed surface of the pressure-sensitive adhesive coating film on the first release liner was coated with a polyester film (second release liner) having a thickness of 38 μm, one side of which was subjected to silicone release treatment, so that the release-treated surface of the second release liner was applied to the adhesive coating film. Covered to contact. Next, the adhesive coating film between the 1st and 2nd peeling liner was irradiated with the ultraviolet-ray of 5 mW/cm<2> of illuminance for 360 second by the black light lamp. Thus, a pressure-sensitive adhesive sheet coated on both sides with the release liner was obtained. Next, a corona treatment is applied to the second surface of the TAC film on which the above-described adhesive layer to the antireflection layer is laminated, and after peeling the first release liner from the pressure-sensitive adhesive sheet, a laminator is used to remove the TAC film. One side of the pressure-sensitive adhesive sheet (the side exposed by peeling of the first release liner) was bonded to the two sides.

As described above, the optical film of Example 1 was produced. The optical film of Example 1 includes a composite film portion (transparent substrate, HC layer, adhesive layer, antireflection layer, antifouling layer) and an adhesive layer in contact with the transparent substrate of the composite film portion.

<Preparation of Acrylic Polymer P>

First, 100 parts by mass of toluene, 60 parts by mass of dicyclopentanyl methacrylate (DCPMA) (trade name "FA-513M", manufactured by Hitachi Chemical Industry Co., Ltd.), 40 parts by mass of methyl methacrylate (MMA), and as a chain transfer agent The mixture of 3.5 parts by mass of α-thioglycerol (TGR) in the reaction vessel was stirred at 70°C for 1 hour under a nitrogen atmosphere. Next, after adding 0.2 mass part of azobisisobutyronitrile as a thermal polymerization initiator to this mixture, the polymerization reaction was advanced at 70 degreeC for 2 hours, and then the polymerization reaction was advanced at 80 degreeC for 2 hours. Thereafter, the reaction liquid was dried in a temperature atmosphere of 130°C to remove toluene, chain transfer agent, and unreacted monomers. Thus, a solid acrylic polymer P was obtained.

[Examples 2 to 4]

Except for changing the discharge power in the plasma treatment of the surface of the HC layer to 300 W to 500 W (Example 2), 700 W (Example 3) or 1000 W (Example 4), the optics of Example 1 In the same manner as the film, each optical film of Examples 2 to 4 was produced.

[Examples 5 to 9]

In the preparation of the mixed composition M in the process of forming the HC layer, the "NC035" and the "binder A" were mixed so that the amount of nano-silica particles was 30 parts by mass based on the total amount of 100 parts by mass of the acrylic resin and nano-silica particles. And, the discharge power in the plasma treatment for the surface of the HC layer is 100 W (Example 5), 300 W (Example 6), 500 W (Example 7), 700 W (Example 8) or 1000 W Except having set it as W (Example 9), it carried out similarly to the optical film of Example 1, and produced each optical film of Examples 5-9.

[Examples 10 to 14]

The discharge power in the plasma treatment of the surface of the HC layer was 100 W (Example 10), 300 W (Example 11), 500 W (Example 12), 700 W (Example 13) or 1000 W (Example 11). 14), and in the sputtering method for forming the first low refractive index layer and the second low refractive index layer, the film formation pressure was set to 0.5 Pa, and the second surface of the TAC film was not corona treated. Each optical film of Examples 10 to 14 was produced in the same manner as the optical film of .

[Comparative Examples 1 to 5]

In each sputtering method for forming the first high refractive index layer and the second high refractive index layer, the film formation pressure is set to 0.3 Pa, and in the sputtering method for forming the first low refractive index layer and the second low refractive index layer, the film formation pressure is Except having set it as 0.2 Pa, it carried out similarly to the optical film of Examples 10-14, and produced the optical film of Comparative Examples 1-5.

[Comparative Examples 6 to 10]

In each sputtering method for forming the first high refractive index layer and the second high refractive index layer, the film formation pressure was set to 0.3 Pa, and the optics of Examples 5 to 9 except that the second surface of the TAC film was not subjected to corona treatment. Optical films of Comparative Examples 6 to 10 were produced in the same manner as the film.

<permeability>

The water vapor transmission rate of the composite film part (the adhesive layer was not bonded) of each optical film of Examples 1-14 and Comparative Examples 1-10 was investigated. Specifically, in accordance with JIS K 7129:2008, the water vapor transmission rate (g/m 2 ·24 h) of the composite film portion was measured in an atmosphere at a temperature of 40°C and a relative humidity of 90%. The results are shown in Table 1.

<Peel strength>

In each of the optical films of Examples 1 to 14 and Comparative Examples 1 to 10, the peel strength between the transparent substrate and the pressure-sensitive adhesive layer was investigated. Specifically, first, the second peeling liner was peeled off from the pressure-sensitive adhesive layer of the optical film, and a back grind tape (trade name "BT-315", manufactured by Nitto Electric Co., Ltd.) was bonded to the exposed surface of the pressure-sensitive adhesive layer thus exposed. Next, a test piece (width 25 mm x length 100 mm) was cut out from the back grind optical film. Next, about the test piece, the adhesive force between the transparent substrate and the pressure-sensitive adhesive layer was measured as peel strength (N/25 mm) with a tensile tester (trade name "Autograph AGS-J", manufactured by Shimadzu Corporation). In this measurement, the measurement temperature was 23°C, the relative humidity was 50%, the tensile angle was 180°, and the tensile speed was 300 mm/min. Table 1 shows the measurement results.

<Bubble evaluation test>

For each optical film of Examples 1 to 14 and Comparative Examples 1 to 10, the presence or absence of air bubbles at the interface between the transparent substrate and the pressure-sensitive adhesive layer was investigated after the weather resistance test.

Specifically, first, after peeling off the second peeling liner from the pressure-sensitive adhesive layer in the optical film, the pressure-sensitive adhesive layer of the optical film is subjected to a crimping operation in which a 2 kg hand roller is reciprocated once with respect to a glass plate having a thickness of 5 mm. It was bonded together to produce a sample. Next, the sample (glass plate with optical film) was placed in a test chamber of a weather resistance tester (trade name "I SPA SUV-W161", manufactured by Iwasaki Electric Co., Ltd.), and a weather resistance test with ultraviolet irradiation was conducted. In this test, the temperature was 80°C, the relative humidity was 45%, the irradiation intensity of ultraviolet rays was 150 mW/cm 2 , and the sample still time was 32.5 hours.

And in the sample after the test, the presence or absence of air bubbles at the interface between the transparent substrate and the pressure-sensitive adhesive layer was observed. In the observation, visual observation and optical microscope observation were used together. As a result, in the optical films of Examples 1 to 4 and 7 to 14, bubbles were not observed either by visual observation or optical microscope observation (in Table 1, it is described as "no" as an observation result). In the optical films of Examples 5 and 6, although not confirmed by visual observation, bubbles with a maximum diameter of 100 μm or less were observed by optical microscopic observation (in Table 1, it is described as “smile” as an observation result). In the optical films of Comparative Examples 1 to 10, bubbles were observed by visual observation, and the maximum diameter of the bubbles was about several millimeters (in Table 1, it is described as "existent" as an observation result).

Further, on the two-dimensional coordinate plane defined by the horizontal axis representing peel strength (N/25 mm) and the vertical axis representing moisture permeability (g/m2 24 h), the value of peel strength measured for each optical film is expressed as x-coordinate. In addition, the value of the moisture permeability was plotted as the y coordinate. The results are shown in FIG. 2 .

[evaluation]

On the two-dimensional coordinate plane shown in FIG. 2, the plots of each light-transmitting film of Comparative Examples 1 to 10 are located in a region below the straight line L1 indicated by Y = -26.6 X + 502. That is, for each of the light-transmitting films of Comparative Examples 1 to 10, the peel strength X (N/25 mm) between the transparent substrate and the pressure-sensitive adhesive layer and the water vapor transmission rate Y (g/m 2 24 h) of the composite film portion were 26.6 X + Y ≥ 502 is not satisfied.

On the other hand, on the two-dimensional coordinate plane shown in FIG. 2, the plots of each light-transmitting film of Examples 1 to 14 are located within a region equal to or greater than the straight line L1 indicated by Y = -26.6 X + 502. That is, each of the light-transmitting films of Examples 1 to 14 had a peel strength X (N/25 mm) between the transparent substrate and the pressure-sensitive adhesive layer and a water vapor transmission rate Y (g/m 2 24 h) of the composite film portion of 26.6 X + It satisfies Y ≥ 502. Each of the light-transmitting films of Examples 1 to 14 having such a configuration is suitable for suppressing the formation of air bubbles at the interface between the transparent substrate and the pressure-sensitive adhesive layer.

In addition, on the two-dimensional coordinate plane shown in FIG. 2, the plots of each light-transmitting film of Examples 1 to 4 and 7 to 14 are located within the region equal to or greater than the straight line L2 indicated by Y = -26.6 X + 527. That is, each of the light-transmitting films of Examples 1 to 4 and 7 to 14 had peel strength X (N/25 mm) between the transparent substrate and the pressure-sensitive adhesive layer and moisture permeability Y (g/m 2 24 h) of the composite film portion. , 26.6 X + Y ≥ 527. Each of the light-transmitting films of Examples 1 to 4 and 7 to 10 having such a configuration is particularly suitable for suppressing the formation of air bubbles at the interface between the transparent substrate and the pressure-sensitive adhesive layer.

The embodiment described above is an illustration of the present invention, and the present invention should not be interpreted limitedly by the embodiment. Modifications of the present invention clear by those skilled in the art are included in the claims described later.

The optical film of the present invention can be applied to an antireflection film, a transparent conductive film, and an electromagnetic wave shielding film.

F: optical film
100: composite film unit
10: transparent substrate
20: optical functional layer
21: first high refractive index layer
22: first low refractive index layer
23: second high refractive index layer
24: second low refractive index layer
31: hard coat layer
32: adhesion layer
33: antifouling layer
101: adhesive layer

Claims (9)

A composite film portion comprising a transparent substrate and an optical function layer in this order;
An adhesive layer in contact with the opposite side to the optical function layer in the transparent substrate is provided,
The peel strength X (N/25 mm) between the transparent substrate and the pressure-sensitive adhesive layer and the moisture permeability Y (g/m 2 24 h) of the composite film portion satisfy 26.6 X + Y ≥ 502, characterized in that , optical film. According to claim 1,
An optical film characterized in that the optical function layer is an antireflection layer. According to claim 2,
The optical film, characterized in that the antireflection layer alternately includes a high refractive index layer having a relatively high refractive index and a low refractive index layer having a relatively small refractive index. According to claim 1,
The optical film characterized in that the pressure-sensitive adhesive layer contains an acrylic polymer as a base polymer. According to claim 1,
An optical film, characterized in that the transparent substrate is a triacetyl cellulose film. According to claim 1,
The optical film characterized in that the composite film portion further includes a hard coat layer between the transparent substrate and the optical function layer. According to claim 6,
An optical film characterized in that the hard coat layer contains metal oxide fine particles. According to claim 7,
The optical film, characterized in that the metal oxide fine particles are nano-silica particles. According to claim 6,
An optical film characterized in that a surface of the hard coat layer on the side of the optical function layer is corona treated.