Optical laminate with surface protective film

Abstract

To provide an optical laminate with a surface protective film capable of suppressing generation of air bubbles and adhesive residue while improving antifouling properties.SOLUTION: An optical laminate 10 comprises a transparent film substrate 11, an antifouling layer 12 and a surface protective film 13 in this order. The surface protective film 13 includes a substrate layer 14 and a pressure-sensitive adhesive layer 15. The antifouling layer 12 and the pressure-sensitive adhesive layer 15 are in contact with each other. Surface hardness of a main surface 15a of the pressure-sensitive adhesive layer 15 on the antifouling layer 12 side has surface hardness of 0.01 MPa or more and 0.05 MPa or less, or 0.30 MPa or more and 3.00 MPa or less. A water contact angle of the main surface 12a of the antifouling layer 12 on the adhesive layer 15 side is 115° or more. Adhesion strength between the antifouling layer 12 and the pressure-sensitive adhesive layer 15 is 0.01 N / 50 mm or more and 0.15 N / 50 mm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical laminate with a surface protective film. [Background technology]

[0002] Antireflection films placed on the outermost surfaces of image display devices, position detection films for touch panels, window films attached to window panes or show windows, and the like are used in a state where they can be touched from the outside, and are therefore susceptible to contamination by fingerprints, finger marks, dust, etc. Therefore, an antifouling layer is provided for the purpose of preventing contamination from the external environment and facilitating the removal of adhered contaminants.

[0003] In order to prevent these optical films (optical laminates) from being scratched or contaminated before use during processing, transportation, etc., a surface protective film is temporarily attached to the surface of the optical laminate (more specifically, the surface of the antifouling layer) (see, for example, Patent Document 1). Hereinafter, an optical laminate to which a surface protective film is temporarily attached may be referred to as an "optical laminate with a surface protective film" or simply as an "optical laminate."

[0004] In the optical laminate with a surface protective film (laminated plastic film for optical filters) described in Patent Document 1, an adhesive layer made of a pressure-sensitive adhesive and a release film (release liner) are laminated in this order on the side opposite the surface protective film. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-151996 Summary of the Invention [Problem to be solved by the invention]

[0006] When an image display device is manufactured using the optical laminate described in Patent Document 1, for example, after peeling off the release liner of the optical laminate, the exposed adhesive layer is attached to an image display panel, and a process (high-temperature, high-pressure process) is carried out in which the image display panel and the adhesive layer are allowed to blend under high temperature and high pressure. The high-temperature, high-pressure process is usually carried out with a surface protection film temporarily attached.

[0007] On the other hand, the antifouling layer tends to have poor adhesion to the surface protective film due to its tendency to easily repel moisture and oil. For this reason, air bubbles may form between the antifouling layer and the surface protective film (more specifically, the adhesive layer of the surface protective film) during the high-temperature, high-pressure process. Air bubbles formed between the antifouling layer and the surface protective film may be judged to result in poor appearance. Hereinafter, the defect of air bubbles forming between the antifouling layer and the surface protective film (more specifically, the adhesive layer of the surface protective film) under high temperature and high pressure may be simply referred to as "air bubble formation."

[0008] Furthermore, if the adhesive strength of the pressure-sensitive adhesive layer of the surface protection film is increased in order to improve the adhesion between the antifouling layer and the surface protection film, adhesive residue may remain on the surface of the antifouling layer when the surface protection film is peeled off from the antifouling layer.

[0009] It is difficult to suppress the occurrence of bubbles and adhesive residue while improving the stain-resistant properties of the stain-resistant layer using only the technique described in Patent Document 1.

[0010] The present invention has been made in view of the above circumstances, and its object is to provide an optical laminate with a surface protective film that can suppress the generation of bubbles and adhesive residue while improving antifouling properties. [Means for solving the problem]

[0011] <Aspects of the present invention> The present invention includes the following aspects.

[0012] [1] An optical laminate with a surface protective film, comprising a transparent film substrate, an antifouling layer, and a surface protective film in this order, the surface protection film has a base layer and a pressure-sensitive adhesive layer, the antifouling layer and the pressure-sensitive adhesive layer are in contact with each other, the surface hardness of the main surface of the pressure-sensitive adhesive layer on the antifouling layer side is 0.01 MPa or more and 0.05 MPa or less, or 0.30 MPa or more and 3.00 MPa or less; the water contact angle of the main surface of the antifouling layer on the side of the pressure-sensitive adhesive layer is 115° or more; An optical laminate with a surface protective film, wherein the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer is 0.01 N / 50 mm or more and 0.15 N / 50 mm or less.

[0013] [2] The optical laminate with a surface protective film according to [1], wherein the surface hardness of the main surface of the pressure-sensitive adhesive layer on the antifouling layer side is 0.30 MPa or more and 3.00 MPa or less.

[0014] [3] The optical laminate with a surface protective film according to [1] or [2], wherein the antifouling layer is a vacuum-deposited film.

[0015] [4] The optical laminate with a surface protective film according to any one of [1] to [3] above, wherein the thickness of the pressure-sensitive adhesive layer is 5 μm or more and 50 μm or less.

[0016] [5] The transparent film substrate includes a transparent film and a hard coat layer provided on a first main surface side of the transparent film, The optical laminate with a surface protective film according to any one of [1] to [4] above, wherein the antifouling layer is provided on the hard coat layer side of the transparent film substrate.

[0017] [6] The optical laminate with a surface protective film according to any one of [1] to [5] above, further comprising an antireflection layer provided between the transparent film substrate and the antifouling layer.

[0018] [7] The optical laminate with a surface protective film according to [6], further comprising a primer layer provided between the transparent film substrate and the antireflection layer. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide an optical laminate with a surface protective film that can suppress the generation of bubbles and adhesive residue while improving antifouling properties. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a cross-sectional view showing an example of an optical laminate with a surface protective film according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] Preferred embodiments of the present invention will be described in detail below, but the present invention is not limited thereto. In addition, all academic and patent documents described in this specification are incorporated herein by reference.

[0022] First, the terms used in this specification will be explained. "Refractive index" refers to the refractive index for light with a wavelength of 550 nm in an atmosphere at a temperature of 23°C. The "main surface" of a layered product (more specifically, a pressure-sensitive adhesive layer, a transparent film substrate, an antifouling layer, a surface protective film, a transparent film, a hard coat layer, a primer layer, an antireflection layer, a substrate layer, an optical laminate with a surface protective film, etc.) refers to the surface perpendicular to the thickness direction of the layered product. The "first main surface" of a layered product refers to one of the two main surfaces of the layered product. The "second main surface" of a layered product refers to the main surface of the layered product opposite to the first main surface. The "solid content" refers to non-volatile components in the composition, such as components other than the solvent.

[0023] Unless otherwise specified, the numerical value for the "thickness (film thickness)" of a layered material is the arithmetic mean value of 10 measured values obtained by observing a cross section of the layered material cut in the thickness direction with an electron microscope, randomly selecting 10 measurement points from the cross section image, and measuring the thickness of the selected 10 measurement points.

[0024] Unless otherwise specified, the number average primary particle diameter of particles is the number average value of the equivalent circle diameters (Heywood diameter: diameter of a circle having the same area as the projected area of a primary particle) of 100 primary particles measured using a scanning electron microscope and image processing software (for example, "ImageJ" manufactured by the National Institutes of Health, USA).

[0025] Hereinafter, the compound and its derivatives may be collectively referred to by adding "based" after the compound name. Furthermore, when the compound name is followed by "based" to represent the name of a polymer, unless otherwise specified, it means that the repeating unit of the polymer is derived from the compound or its derivative. Furthermore, acrylic and methacrylic may be collectively referred to as "(meth)acrylic." Furthermore, acrylate and methacrylate may be collectively referred to as "(meth)acrylate."

[0026] Unless otherwise specified, the components, functional groups, etc. exemplified in this specification may be used alone or in combination of two or more kinds.

[0027] The drawings referred to in the following description mainly show each component in a schematic manner for ease of understanding, and the size, number, shape, etc. of each component shown may differ from the actual size due to the convenience of creating the drawings.

[0028] <Optical laminate with surface protection film> The optical laminate with a surface protective film according to this embodiment (hereinafter sometimes referred to as "optical laminate A") comprises, in this order, a transparent film substrate, an antifouling layer, and a surface protective film. The surface protective film has a substrate layer and a pressure-sensitive adhesive layer. The antifouling layer and the pressure-sensitive adhesive layer are in contact with each other. The surface hardness of the main surface of the pressure-sensitive adhesive layer facing the antifouling layer is 0.01 MPa or more and 0.05 MPa or less, or 0.30 MPa or more and 3.00 MPa or less. The water contact angle of the main surface of the antifouling layer facing the pressure-sensitive adhesive layer is 115° or more. The adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer is 0.01 N / 50 mm or more and 0.15 N / 50 mm or less.

[0029] The methods for measuring "surface hardness," "water contact angle," and "adhesion strength" are all the same as or similar to the measurement methods in the examples described below.

[0030] Hereinafter, the surface hardness of the main surface of the pressure-sensitive adhesive layer facing the antifouling layer may be simply referred to as the "surface hardness of the pressure-sensitive adhesive layer." The water contact angle of the main surface of the antifouling layer facing the pressure-sensitive adhesive layer may be simply referred to as the "water contact angle of the antifouling layer." The numerical ranges of surface hardness, "0.01 MPa or more and 0.05 MPa or less" and "0.30 MPa or more and 3.00 MPa or less," may be referred to as the "first range" and the "second range," respectively.

[0031] The optical laminate A has the above-described configuration, and therefore can improve the antifouling properties while suppressing the occurrence of bubbles and adhesive residue. The reason for this is presumed to be as follows.

[0032] In the optical laminate A, the water contact angle of the antifouling layer is 115° or more, which reduces the influence of contamination from the external environment (fingerprints, dirt, dust, etc.) during use of the optical laminate A (after the surface protective film is peeled off from the antifouling layer), and also makes it easy to remove contaminants adhering to the surface of the antifouling layer. Therefore, the optical laminate A can improve antifouling properties.

[0033] On the other hand, if the water contact angle of the antifouling layer is 115° or more, the adhesion between the antifouling layer and the surface protection film is usually low, and air bubbles are likely to form between the pressure-sensitive adhesive layer of the surface protection film and the antifouling layer during high-temperature, high-pressure processing. In contrast, in the optical laminate A, the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer is maintained at 0.01 N / 50 mm or more, while the surface hardness of the pressure-sensitive adhesive layer is within the first or second range, thereby suppressing the formation of air bubbles. Specifically, when the surface hardness of the pressure-sensitive adhesive layer is within the first range (0.01 MPa or more and 0.05 MPa or less), the pressure-sensitive adhesive layer easily conforms to the surface shape of the antifouling layer, thereby suppressing the formation of air bubbles between the pressure-sensitive adhesive layer and the antifouling layer. On the other hand, when the surface hardness of the pressure-sensitive adhesive layer is within the second range (0.30 MPa or more and 3.00 MPa or less), deformation of the pressure-sensitive adhesive layer is suppressed, thereby suppressing the formation of air bubbles between the pressure-sensitive adhesive layer and the antifouling layer.

[0034] In addition, in the optical laminate A, the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer is 0.15 N / 50 mm or less, so when the surface protection film is peeled off from the antifouling layer, the occurrence of adhesive residue on the surface of the antifouling layer can be suppressed.

[0035] In this embodiment, when the surface hardness of the adhesive layer is within the first range, in order to further suppress the generation of bubbles, the surface hardness of the adhesive layer is preferably 0.01 MPa or more and 0.04 MPa or less, more preferably 0.01 MPa or more and 0.03 MPa or less, and even more preferably 0.01 MPa or more and 0.02 MPa or less.

[0036] In this embodiment, when the surface hardness of the pressure-sensitive adhesive layer is within the second range, in order to further suppress bubble generation, the surface hardness of the pressure-sensitive adhesive layer is preferably 0.40 MPa or more, more preferably 0.50 MPa or more, even more preferably 0.60 MPa or more, and even more preferably more than 0.60 MPa, and may be 0.61 MPa or more, 0.62 MPa or more, 0.63 MPa or more, 0.64 MPa or more, 0.65 MPa or more, 0.66 MPa or more, 0.67 MPa or more, 0.68 MPa or more, 0.69 MPa or more, or 0.70 MPa or more. Furthermore, in this embodiment, when the surface hardness of the pressure-sensitive adhesive layer is within the second range, in order to easily adjust the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer to 0.01 N / 50 mm or more, the surface hardness of the pressure-sensitive adhesive layer is preferably 2.50 MPa or less, more preferably 2.00 MPa or less.

[0037] In this embodiment, in order to further suppress the occurrence of bubbles and adhesive residue, the surface hardness of the pressure-sensitive adhesive layer is preferably within the second range.

[0038] In this embodiment, to further enhance the antifouling properties, the water contact angle of the antifouling layer is preferably 116° or more, more preferably 117° or more, and even more preferably 118° or more. Furthermore, in this embodiment, to easily adjust the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer to 0.01 N / 50 mm or more, the water contact angle of the antifouling layer is preferably 125° or less, and more preferably 120° or less.

[0039] In this embodiment, in order to further suppress the generation of bubbles, the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer is preferably 0.02 N / 50 mm or more, more preferably 0.03 N / 50 mm or more, and even more preferably 0.04 N / 50 mm or more. In addition, in this embodiment, in order to further suppress the generation of adhesive residue, the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer is preferably 0.14 N / 50 mm or less, more preferably 0.13 N / 50 mm or less, and even more preferably 0.12 N / 50 mm or less.

[0040] The optical laminate A will be described in detail below with reference to the drawings as appropriate. Figure 1 is a cross-sectional view showing an example of the optical laminate A (optical laminate 10).

[0041] The optical laminate 10 shown in FIG. 1 includes a transparent film substrate 11, an antifouling layer 12, and a surface protective film 13, in this order. The surface protective film 13 includes a substrate layer 14 and a pressure-sensitive adhesive layer 15. The antifouling layer 12 and the pressure-sensitive adhesive layer 15 are in contact with each other. The surface hardness of the main surface 15a of the pressure-sensitive adhesive layer 15 facing the antifouling layer 12 is 0.01 MPa or more and 0.05 MPa or less, or 0.30 MPa or more and 3.00 MPa or less. The water contact angle of the main surface 12a of the antifouling layer 12 facing the pressure-sensitive adhesive layer 15 is 115° or more. The adhesion strength between the antifouling layer 12 and the pressure-sensitive adhesive layer 15 is 0.01 N / 50 mm or more and 0.15 N / 50 mm or less.

[0042] The surface hardness of the main surface 15a of the pressure-sensitive adhesive layer 15 facing the antifouling layer 12 can be adjusted, for example, by changing at least one of the formulation of the pressure-sensitive adhesive composition used to form the pressure-sensitive adhesive layer 15 (e.g., the type of base polymer, the type of crosslinking agent, the amount of crosslinking agent, etc.) and the thickness of the pressure-sensitive adhesive layer 15. The water contact angle of the main surface 12a of the antifouling layer 12 facing the antifouling layer 12 can be adjusted, for example, by changing at least one of the type of antifouling agent used to form the antifouling layer 12, the method for forming the antifouling layer 12, and the thickness of the antifouling layer 12. The adhesion strength between the antifouling layer 12 and the pressure-sensitive adhesive layer 15 can be adjusted, for example, by changing at least one of the formulation of the pressure-sensitive adhesive composition used to form the pressure-sensitive adhesive layer 15 (e.g., the type of base polymer, the type of crosslinking agent, the amount of crosslinking agent, etc.), the thickness of the pressure-sensitive adhesive layer 15, the type of antifouling agent used to form the antifouling layer 12, the method for forming the antifouling layer 12, and the thickness of the antifouling layer 12.

[0043] The surface protective film 13 has a base layer 14 and a pressure-sensitive adhesive layer 15 laminated on the antifouling layer 12 side of the base layer 14. The surface protective film 13 is releasably attached to the antifouling layer 12 by the pressure-sensitive adhesive layer 15. The main surface of the base layer 14 opposite to the pressure-sensitive adhesive layer 15 side may be subjected to an antistatic treatment.

[0044] The transparent film substrate 11 includes a transparent film 16 and a hard coat layer 17 provided on the first main surface 16a side of the transparent film 16. The antifouling layer 12 is provided on the hard coat layer 17 side of the transparent film substrate 11. An adhesive layer (not shown) made of a pressure-sensitive adhesive may be provided on the second main surface 16b side of the transparent film 16. When an adhesive layer is provided on the second main surface 16b side of the transparent film 16, a release liner (not shown) may be temporarily attached to the adhesive layer.

[0045] The optical laminate 10 also includes an antireflection layer 20 between the transparent film substrate 11 and the antifouling layer 12. The optical laminate 10 also includes a primer layer 25 between the transparent film substrate 11 and the antireflection layer 20. The optical laminate 10 functions as an antireflection film, for example, when attached to the surface of an image display panel (not shown).

[0046] The antireflection layer 20 has four layers, namely, a high refractive index layer 21, a low refractive index layer 22, a high refractive index layer 23, and a low refractive index layer 24, in this order from the primer layer 25 side. Details of the high refractive index layer and the low refractive index layer will be described later. The antireflection layer is not limited to a four-layer structure like the antireflection layer 20, and may have a two-layer structure, a three-layer structure, a five-layer structure, or a stacked structure of six or more layers. The antireflection layer is preferably an alternating laminate of two or more high refractive index layers and two or more low refractive index layers. In order to reduce reflection at the air interface, it is preferable that the outermost layer of the antireflection layer (the layer farthest from the primer layer) be a low refractive index layer.

[0047] In the example shown in Fig. 1, the transparent film substrate has a hard coat layer, but the transparent film substrate usable in the present invention is not limited to the above example. For example, the transparent film substrate usable in the present invention does not have to have a hard coat layer. When the transparent film substrate does not have a hard coat layer, for example, a transparent film (transparent film 16 in the example shown in Fig. 1) can be used as the transparent film substrate.

[0048] Next, each layer included in the optical laminate 10 will be described in detail.

[0049] [Transparent Film 16] The transparent film 16 is, for example, a flexible, transparent resin film. Examples of materials constituting the transparent film 16 include polyester resin, polyolefin resin, polystyrene resin, acrylic resin, polycarbonate resin, polyethersulfone resin, polysulfone resin, polyamide resin, polyimide resin, cellulose resin, norbornene resin, polyarylate resin, and polyvinyl alcohol resin. Examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate. Examples of polyolefin resins include polyethylene, polypropylene, and cycloolefin polymer (COP). Examples of cellulose resins include triacetyl cellulose (TAC). These materials may be used alone or in combination. From the viewpoints of transparency and strength, the material of the transparent film 16 is preferably one selected from the group consisting of polyester resin, polyolefin resin, and cellulose resin, more preferably one selected from the group consisting of PET, COP, and TAC, and even more preferably TAC. In other words, as the transparent film 16, a type of film selected from the group consisting of polyester resin film, polyolefin resin film, and cellulose resin film is preferred, a type of film selected from the group consisting of PET film, COP film, and TAC film is more preferred, and a TAC film is even more preferred.

[0050] From the viewpoint of strength, the thickness of the transparent film 16 is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 20 μm or more. From the viewpoint of handleability, the thickness of the transparent film 16 is preferably 300 μm or less, and more preferably 200 μm or less.

[0051] One or both main surfaces of the transparent film 16 may be subjected to a surface modification treatment, such as a corona treatment, a plasma treatment, an ozone treatment, a primer treatment, a glow treatment, or a coupling agent treatment.

[0052] From the viewpoint of improving the transparency of the optical laminate 10, the total light transmittance (JIS K 7375-2008) of the transparent film 16 is preferably 80% or more, more preferably 90% or more, and even more preferably 95% or more and 100% or less.

[0053] [Hard coat layer 17] The hard coat layer 17 is a layer that enhances the mechanical properties, such as hardness and elastic modulus, of the optical laminate 10. The hard coat layer 17 is made of, for example, a cured product of a curable resin composition (a composition for forming a hard coat layer). Examples of the curable resin contained in the curable resin composition include polyester resin, acrylic resin, urethane resin, urethane acrylate resin, amide resin, silicone resin, epoxy resin, and melamine resin. These curable resins may be used alone or in combination of two or more. From the viewpoint of enhancing the hardness of the hard coat layer 17, the curable resin is preferably one or more selected from the group consisting of acrylic resin and urethane acrylate resin, and more preferably urethane acrylate resin.

[0054] Examples of the curable resin composition include an ultraviolet-curable resin composition and a thermosetting resin composition. From the viewpoint of improving the productivity of the optical laminate 10, the curable resin composition is preferably an ultraviolet-curable resin composition. The ultraviolet-curable resin composition contains one or more selected from the group consisting of an ultraviolet-curable monomer, an ultraviolet-curable oligomer, and an ultraviolet-curable polymer. A specific example of the ultraviolet-curable resin composition is a composition for forming a hard coat layer described in JP 2016-179686 A.

[0055] The curable resin composition may also contain particles having a number-average primary particle diameter of 1.0 μm or more (hereinafter, sometimes referred to as "microparticles"). That is, the hard coat layer 17 may contain microparticles. Blending microparticles into the curable resin composition makes it possible to adjust the hardness, surface roughness, refractive index, and antiglare properties of the hard coat layer 17. Examples of microparticles include metal (or semi-metal) oxide particles, glass particles, and organic particles. Examples of materials for metal (or semi-metal) oxide particles include silica, alumina, titania, zirconia, calcium oxide, tin oxide, indium oxide, cadmium oxide, and antimony oxide. Examples of materials for organic particles include silicone, polymethyl methacrylate, polystyrene, polyurethane, (meth)acrylate compound-styrene copolymer, benzoguanamine, melamine, polymethylsilsesquioxane, and polycarbonate.

[0056] To easily adjust the antiglare properties of the hard coat layer 17, the number average primary particle diameter of the microparticles is preferably 1.0 μm or more and 5.0 μm or less, and more preferably 2.0 μm or more and 4.0 μm or less.

[0057] In order to easily adjust the antiglare properties of the hard coat layer 17, the amount of microparticles in the hard coat layer 17 is preferably 0.5 parts by weight or more relative to 100 parts by weight of the curable resin. The upper limit of the amount of microparticles in the hard coat layer 17 is, for example, 90 parts by weight, preferably 80 parts by weight, and may be 70 parts by weight relative to 100 parts by weight of the curable resin.

[0058] When the hard coat layer 17 contains microparticles, irregularities are formed on the surface of the hard coat layer 17, and the irregular shape tends to be reflected on the surface of the antifouling layer 12. When the irregular shape of the surface of the hard coat layer 17 is reflected on the surface of the antifouling layer 12, air bubbles are usually more likely to be generated between the pressure-sensitive adhesive layer 15 and the antifouling layer 12 during a high-temperature, high-pressure process. In contrast, in the optical laminate 10, the adhesion strength between the antifouling layer 12 and the pressure-sensitive adhesive layer 15 is ensured to be 0.01 N / 50 mm or more, and the surface hardness of the pressure-sensitive adhesive layer 15 is within the first range or the second range, so that the generation of air bubbles is suppressed.

[0059] The curable resin composition may also contain particles having a number-average primary particle diameter of less than 1.0 μm (hereinafter, these may be referred to as "nanoparticles"). That is, the hard coat layer 17 may contain nanoparticles. When the hard coat layer 17 is made of a cured product of a curable resin composition containing nanoparticles, fine irregularities are formed on the surface of the hard coat layer 17, which tends to improve adhesion between the hard coat layer 17 and a layer formed thereon (for example, the primer layer 25).

[0060] From the viewpoint of forming a fine uneven shape that contributes to improving adhesion, the number average primary particle diameter of the nanoparticles is preferably 20 nm or more and 80 nm or less, more preferably 25 nm or more and 70 nm or less, and even more preferably 30 nm or more and 60 nm or less.

[0061] As a material for the nanoparticles, inorganic oxides are preferred. Examples of inorganic oxides include oxides of metals (or semimetals) such as silicon oxide (silica), titanium oxide, aluminum oxide, zirconium oxide, niobium oxide, zinc oxide, tin oxide, cerium oxide, and magnesium oxide. The inorganic oxide may also be a composite oxide of multiple (semi)metals. Among the exemplified inorganic oxides, silicon oxide is preferred because of its high effect of improving adhesion. In other words, silicon oxide particles (silica particles) are preferred as nanoparticles. Functional groups such as acrylic groups and epoxy groups may be introduced onto the surfaces of inorganic oxide particles as nanoparticles in order to improve adhesion and affinity with resins.

[0062] The amount of nanoparticles in the hard coat layer 17 is preferably 5 parts by weight or more, and may be 10 parts by weight or more, 20 parts by weight or more, or 30 parts by weight or more, relative to 100 parts by weight of the curable resin. If the amount of nanoparticles is 5 parts by weight or more, it is possible to further improve adhesion to a layer formed on the hard coat layer 17. The upper limit of the amount of nanoparticles in the hard coat layer 17 is, for example, 90 parts by weight, preferably 80 parts by weight, and may be 70 parts by weight, relative to 100 parts by weight of the curable resin.

[0063] The thickness of the hard coat layer 17 is preferably 1 μm or more, more preferably 2 μm or more, from the viewpoint of increasing the hardness of the hard coat layer 17. The thickness of the hard coat layer 17 is preferably 50 μm or less, more preferably 40 μm or less, even more preferably 35 μm or less, and still more preferably 30 μm or less, from the viewpoint of ensuring the flexibility of the optical laminate 10.

[0064] The main surface of the hard coat layer 17 opposite to the transparent film 16 side may be subjected to a surface modification treatment. Examples of surface modification treatments include plasma treatment, corona treatment, ozone treatment, primer treatment, glow treatment, and coupling agent treatment. In order to improve adhesion between the hard coat layer 17 and a layer (e.g., the primer layer 25 described below) provided on the side opposite to the transparent film 16 side of the hard coat layer 17, it is preferable that the main surface of the hard coat layer 17 opposite to the transparent film 16 side be plasma treated.

[0065] (Method of forming hard coat layer 17) The hard coat layer 17 is formed, for example, by applying a curable resin composition (composition for forming a hard coat layer) to the first main surface 16a of the transparent film 16, and then removing the solvent and curing the resin as necessary. The composition for forming a hard coat layer contains, for example, the above-mentioned curable resin and a polymerization initiator (e.g., a photopolymerization initiator), and, as necessary, a solvent capable of dissolving or dispersing these components.

[0066] In addition to the above components, the composition for forming a hard coat layer may contain additives such as microparticles, nanoparticles, leveling agents, viscosity modifiers (thixotropic agents, thickeners, etc.), antistatic agents, antiblocking agents, dispersants, dispersion stabilizers, antioxidants, ultraviolet absorbers, antifoaming agents, surfactants, and lubricants.

[0067] The hard coat layer-forming composition can be applied by any suitable method, such as bar coating, roll coating, gravure coating, rod coating, slot orifice coating, curtain coating, fountain coating, or comma coating. The drying temperature of the coating film after application may be set appropriately depending on the composition of the hard coat layer-forming composition, and is, for example, 50°C or higher and 150°C or lower. When the resin component in the hard coat layer-forming composition is a thermosetting resin, the coating film is cured by heating. When the resin component in the hard coat layer-forming composition is a photocurable resin, the coating film is cured by irradiating it with active energy rays such as ultraviolet light. The integrated light intensity of the irradiated light is preferably 100 mJ / cm. 2 More than 500mJ / cm 2 The following is the result.

[0068] [Primer layer 25] To improve adhesion between the transparent film substrate 11 (hard coat layer 17) and the anti-reflection layer 20, a primer layer 25 is preferably provided between the transparent film substrate 11 and the anti-reflection layer 20. Examples of materials for the primer layer 25 include metals (or semi-metals) such as silicon, nickel, chromium, tin, gold, silver, platinum, zinc, titanium, indium, tungsten, aluminum, zirconium, and palladium; alloys of these metals (or semi-metals); and oxides, fluorides, sulfides, and nitrides of these metals (or semi-metals). The oxide constituting the primer layer 25 may be a composite oxide such as indium tin oxide (ITO). Among these, inorganic oxides are preferred as the material for the primer layer 25, with silicon oxide, indium oxide, or ITO being more preferred, and SiOx (x<2) being even more preferred.

[0069] In order to improve the adhesion between the transparent film substrate 11 and the antireflection layer 20 while ensuring the light transmittance of the primer layer 25, the thickness of the primer layer 25 is preferably 0.5 nm or more and 20 nm or less, more preferably 0.5 nm or more and 10 nm or less, and even more preferably 1.0 nm or more and 10 nm or less.

[0070] (Method of forming primer layer 25) The method for forming (depositing) the primer layer 25 is not particularly limited, and may be either a wet coating method or a dry coating method. Dry coating methods such as vacuum deposition, CVD, and sputtering are preferred because they can form a thin film with a uniform thickness. Furthermore, from the viewpoint of improving productivity, a method for depositing the primer layer 25 using a roll-to-roll sputtering deposition device (roll-to-roll sputtering method) is preferred.

[0071] In the roll-to-roll sputtering method, for example, a primer layer 25 and an anti-reflection layer 20 can be continuously formed while transporting a long film (e.g., a transparent film substrate 11) in the longitudinal direction (MD direction). In the sputtering method, film formation is performed while introducing an inert gas such as argon, and optionally a reactive gas such as oxygen, into a film formation chamber. When forming an oxide layer as the primer layer 25, the oxide layer can be formed by sputtering using either an oxide target or reactive sputtering using a metal (or semi-metal) target.

[0072] Examples of power sources for performing the sputtering method include DC power sources, AC power sources, RF power sources, and MFAC power sources (AC power sources with a frequency band of several kHz to several MHz). The power density when performing the sputtering method is, for example, 0.1 W / cm. 2 More than 20W / cm 2 less than or equal to 1 W / cm 2 More than 15W / cm 2The surface temperature of the film-forming roll when sputtering is performed is, for example, −25° C. or higher and 25° C. or lower, and preferably −20° C. or higher and 0° C. or lower. The pressure in the film-forming chamber when sputtering is performed is preferably 0.01 Pa or higher and 10 Pa or lower, more preferably 0.05 Pa or higher and 5 Pa or lower, and even more preferably 0.1 Pa or higher and 1 Pa or lower.

[0073] [Anti-reflection layer 20] The antireflection layer 20 preferably comprises two or more thin films with different refractive indices. Generally, the optical film thickness (product of refractive index and thickness) of the thin films in the antireflection layer is adjusted so that the reversed phases of incident light and reflected light cancel each other out. By making the antireflection layer a multilayer stack of two or more thin films with different refractive indices, it is possible to reduce the reflectance over a wide wavelength range of visible light.

[0074] Examples of thin film materials that constitute the antireflection layer 20 include metal (or semi-metal) oxides, nitrides, fluorides, etc. The antireflection layer 20 is preferably an alternate laminate of high refractive index layers and low refractive index layers.

[0075] The high-refractive index layer has a refractive index of, for example, 1.9 or more, preferably 2.0 or more. Examples of materials for the high-refractive index layer include titanium oxide, niobium oxide (e.g., Nb2O5), zirconium oxide, tantalum oxide, zinc oxide, indium oxide, ITO, and antimony-doped tin oxide (ATO). Among these, at least one material selected from the group consisting of titanium oxide and niobium oxide is preferred. The low-refractive index layer has a refractive index of, for example, 1.6 or less, preferably 1.5 or less. Examples of materials for the low-refractive index layer include silicon oxide (e.g., SiO2), titanium nitride, magnesium fluoride, barium fluoride, calcium fluoride, hafnium fluoride, and lanthanum fluoride. Among these, silicon oxide is preferred. It is particularly preferred to alternately stack niobium oxide thin films as the high-refractive index layer and silicon oxide thin films as the low-refractive index layer. In addition to the low-refractive index layer and the high-refractive index layer, a medium-refractive index layer having a refractive index greater than 1.6 and less than 1.9 may be provided.

[0076] The thickness of each of the high refractive index layer and the low refractive index layer is preferably 5 nm to 200 nm, more preferably 10 nm to 150 nm. The thickness of each layer may be designed depending on the refractive index, layer structure, etc., so that the reflectance of visible light is low.

[0077] When the antireflection layer 20 is a four-layer alternating laminate in which niobium oxide thin films as high refractive index layers and silicon oxide thin films as low refractive index layers are alternately laminated, the antireflection layer 20 may be configured to have, from the hard coat layer 17 side, a niobium oxide thin film having a thickness of 5 nm to 20 nm, a silicon oxide thin film having a thickness of 10 nm to 40 nm, a niobium oxide thin film having a thickness of 65 nm to 120 nm, and a silicon oxide thin film having a thickness of 60 nm to 100 nm, in this order.

[0078] To obtain an antireflection layer 20 with excellent flex resistance, the thickness of the antireflection layer 20 is preferably 140 nm or more and 280 nm or less, more preferably 170 nm or more and 280 nm or less, even more preferably 180 nm or more and 260 nm or less, and even more preferably 190 nm or more and 250 nm or less. In this specification, the "thickness of the antireflection layer" refers to the sum of the thicknesses of the layers constituting the antireflection layer (total thickness).

[0079] (Method of forming antireflection layer 20) The antireflection layer 20 is formed (deposited) on, for example, the primer layer 25 by a wet coating method or a dry coating method. Dry coating methods such as vacuum deposition, CVD, and sputtering are preferred because they can form a thin film with a uniform thickness. From the viewpoint of improving productivity, roll-to-roll sputtering is preferred as a method for depositing the antireflection layer 20. When using the sputtering method, the deposition conditions can be appropriately set, for example, within the conditions explained above in (Method for forming the primer layer 25).

[0080] [Anti-fouling layer 12] The antifouling layer 12 is provided for the purposes of preventing contamination from the external environment and facilitating the removal of adhered contaminants. In order to prevent a decrease in the antireflection performance of the antireflection layer 20, it is preferable that the antifouling layer 12 has a small difference in refractive index from the outermost layer (e.g., a silicon oxide layer) of the antireflection layer 20. The refractive index of the antifouling layer 12 is preferably 1.6 or less, and more preferably 1.55 or less.

[0081] The antifouling layer 12 preferably contains, as an antifouling agent, a fluorine-containing compound having a terminal structure represented by the chemical formula CFO- (more specifically, CF3-O-). Fluorine-containing compounds having a terminal structure represented by the chemical formula CFO- can contribute to a lower refractive index while providing excellent antifouling properties. Among these, alkoxysilane compounds containing a perfluoropolyether skeleton are preferred as the fluorine-containing compound because they are capable of exhibiting excellent water repellency and high antifouling properties. Examples of alkoxysilane compounds containing a perfluoropolyether skeleton include compounds represented by the following general formula: CF3-(OCF2) m -(OC2F4) n -O-(CH2)3-Si(OCH3)3

[0082] In the above general formula, m represents an integer of 1 or more and 51 or less, and n represents an integer of 1 or more and 50 or less.

[0083] The fluorine-containing compound having a terminal structure represented by the chemical formula CFO- may be used alone or in combination of two or more. When the alkoxysilane compound is used as the fluorine-containing compound, the alkoxysilane compound may be present in the antifouling layer 12 in a state in which the terminal alkoxy groups are reacted (crosslinked).

[0084] The thickness of the antifouling layer 12 is, for example, 2 nm or more and 50 nm or less. The thicker the antifouling layer 12, the more improved the antifouling properties tend to be. The thickness of the antifouling layer 12 is preferably 5 nm or more, more preferably 6 nm or more, and even more preferably 7 nm or more. On the other hand, in order to further suppress reflection of external light, the thickness of the antifouling layer 12 is preferably 30 nm or less, more preferably 20 nm or less, and even more preferably 15 nm or less.

[0085] (Method of forming antifouling layer 12) The antifouling layer 12 is formed, for example, on the antireflection layer 20 by a wet coating method (application method) or a dry coating method. When a fluorine-containing compound is used as the material, the antifouling layer 12 is preferably formed by a dry coating method in order to form a uniform film of the fluorine-containing compound. Examples of dry coating methods include vacuum deposition, sputtering, and CVD, with vacuum deposition being preferred. In particular, in order to easily adjust the water contact angle of the antifouling layer 12 to 115° or more, it is preferred to form the antifouling layer 12 by a vacuum deposition method. That is, in order to easily adjust the water contact angle of the antifouling layer 12 to 115° or more, it is preferred that the antifouling layer 12 be a vacuum deposition film.

[0086] [Base material layer 14] The substrate layer 14 is formed, for example, of any appropriate film. Examples of materials for the film include polyester resins such as polyethylene terephthalate resins, polycycloolefin resins such as polynorbornene resins, polyolefin resins such as polypropylene, polyamide resins, polycarbonate resins, and copolymer resins thereof. To increase the hardness of the substrate layer 14, polyester resins are preferred as the material for the substrate layer 14. The thickness of the substrate layer 14 is, for example, 10 μm or more and 200 μm or less, and preferably 20 μm or more and 150 μm or less. The substrate layer 14 may also be a laminate of two or more layers.

[0087] [Adhesive layer 15] In order to increase the adhesive strength to the antifouling layer 12 having a large water contact angle and to further suppress the generation of bubbles, the thickness of the pressure-sensitive adhesive layer 15 is preferably 5 μm or more, and more preferably 10 μm or more. In order to further suppress the generation of adhesive residue, the thickness of the pressure-sensitive adhesive layer 15 is preferably 50 μm or less, more preferably 40 μm or less, and even more preferably 35 μm or less.

[0088] The composition of the adhesive constituting the adhesive layer 15 is not particularly limited, and an adhesive having a base polymer such as an acrylic polymer, a silicone polymer, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate / vinyl chloride copolymer, modified polyolefin, epoxy-based, fluorine-based, natural rubber, synthetic rubber, etc. is suitably selected and used. In particular, an acrylic adhesive having an acrylic polymer as a base polymer is preferably used because of its excellent adhesiveness and optical transparency.

[0089] As the acrylic base polymer of the acrylic pressure-sensitive adhesive, one having a (meth)acrylic acid alkyl ester monomer unit as the main skeleton is suitably used.

[0090] As the (meth)acrylic acid alkyl ester, a (meth)acrylic acid alkyl ester having an alkyl group with 1 to 20 carbon atoms is preferably used. Examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (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, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, Examples of such acrylates include isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, isotridodecyl (meth)acrylate, tetradecyl (meth)acrylate, isotetradecyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isooctadecyl (meth)acrylate, and nonadecyl (meth)acrylate.

[0091] The content of (meth)acrylic acid alkyl ester units is preferably 40% by weight or more, more preferably 50% by weight or more, and even more preferably 60% by weight or more, based on the total amount of monomer units constituting the acrylic polymer. The acrylic polymer may be a copolymer of multiple types of (meth)acrylic acid alkyl esters. The arrangement of the constituent monomer units may be random or block.

[0092] The acrylic pressure-sensitive adhesive preferably contains a monomer component having a crosslinkable functional group as a copolymerization component. Examples of the monomer having a crosslinkable functional group include a hydroxyl group-containing monomer and a carboxyl group-containing monomer. Of these, it is preferable to contain a hydroxyl group-containing monomer as a copolymerization component. The hydroxyl group and the carboxyl group serve as reaction sites with the crosslinking agent described below. By introducing a crosslinked structure into the base polymer, the cohesive strength of the pressure-sensitive adhesive is improved, the pressure-sensitive adhesive exhibits appropriate adhesive strength to the adherend (the antifouling layer 12), and the surface protective film 13 is easily peeled from the adherend, which tends to suppress contamination caused by adhesive residue, etc.

[0093] Examples of the hydroxy group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, etc. Examples of the carboxy group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, etc.

[0094] In addition to the above, the acrylic pressure-sensitive adhesive may contain, as a copolymerizable monomer component, an acid anhydride group-containing monomer, a caprolactone adduct of acrylic acid, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, or the like. In addition, as the modifying monomer, vinyl monomers such as vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methyl vinylpyrrolidone, vinylpyridine, vinyl piperidone, vinyl pyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, styrene, α-methylstyrene, N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; glycol-based acrylic ester monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth)acrylate, and acrylic acid ester monomers such as 2-methoxyethyl acrylate can also be used.

[0095] The ratio of copolymerizable monomer components in the acrylic pressure-sensitive adhesive is not particularly limited, but for example, when a hydroxyl group-containing monomer or a carboxyl group-containing monomer is used as a copolymerizable monomer component for the purpose of introducing crosslinking points, the total content of the hydroxyl group-containing monomer and the carboxyl group-containing monomer is preferably 1% by weight or more and 20% by weight or less, and more preferably 2% by weight or more and 15% by weight or less, of the total amount of monomer components constituting the acrylic polymer.

[0096] The above monomer components are polymerized by various known methods such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization to obtain an acrylic polymer. Solution polymerization is preferred from the viewpoints of cost and the balance of adhesive strength, holding power, and other properties of the pressure-sensitive adhesive. Ethyl acetate, toluene, or the like is used as the solvent for solution polymerization. The solution concentration is, for example, 5% by weight or more and 80% by weight or less. Various known polymerization initiators, such as azo-based and peroxide-based initiators, can be used. A chain transfer agent may be used to adjust the molecular weight. The reaction temperature is, for example, 50°C or more and 100°C or less, and the reaction time is, for example, 1 hour or more and 15 hours or less.

[0097] The molecular weight of the acrylic polymer is adjusted appropriately so that the pressure-sensitive adhesive layer 15 has the desired adhesive strength, and the weight-average molecular weight in terms of polystyrene is, for example, from 50,000 to 2,000,000, preferably from 70,000 to 1,800,000, more preferably from 100,000 to 1,500,000, and even more preferably from 200,000 to 1,000,000. When a crosslinked structure is introduced into the acrylic base polymer, it is preferable that the molecular weight of the polymer before the introduction of the crosslinked structure is within the above range.

[0098] When introducing a crosslinked structure into an acrylic-based polymer, for example, a crosslinking agent is added to the acrylic polymer solution after polymerization, followed by heating as necessary to introduce the crosslinked structure. Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, and metal chelate-based crosslinking agents. Among these, one or more crosslinking agents selected from the group consisting of isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred because they have high reactivity with the hydroxy groups and carboxy groups of the acrylic polymer and facilitate the introduction of crosslinked structures. These crosslinking agents react with functional groups such as hydroxy groups and carboxy groups introduced into the polymer to form crosslinked structures.

[0099] The isocyanate crosslinking agent used is a polyisocyanate having two or more isocyanate groups per molecule. Examples of the isocyanate crosslinking agent include lower aliphatic polyisocyanate compounds such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanate compounds such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate; aromatic isocyanate compounds such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate; and isocyanate adducts such as a tolylene diisocyanate trimer adduct of trimethylolpropane, a hexamethylene diisocyanate trimer adduct of trimethylolpropane, a xylylene diisocyanate trimethylolpropane adduct, and an isocyanurate of hexamethylene diisocyanate.

[0100] The epoxy crosslinking agent is a polyfunctional epoxy compound having two or more epoxy groups in one molecule, and the epoxy group of the epoxy crosslinking agent may be a glycidyl group. Examples of epoxy crosslinking agents include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, and bisphenol-S-diglycidyl ether. As the epoxy-based crosslinking agent, commercially available products such as "Denacol" manufactured by Nagase ChemteX Corporation, "Tetrad X" manufactured by Mitsubishi Gas Chemical Company, Inc., and "Tetrad C" manufactured by Mitsubishi Gas Chemical Company, Inc. may be used.

[0101] When a crosslinking agent is added to the acrylic polymer after polymerization to introduce a crosslinked structure, the amount of crosslinking agent used can be adjusted appropriately depending on the polymer composition, molecular weight, desired adhesive properties, etc. In order to provide the pressure-sensitive adhesive with an appropriate cohesive strength and adjust the peel force when peeling the protective film from the adherend within an appropriate range, the amount of crosslinking agent used is preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, and even more preferably 2 parts by weight or more, per 100 parts by weight of the acrylic polymer. Furthermore, in order to provide appropriate adhesion to the adherend, the amount of crosslinking agent used is preferably 15 parts by weight or less, more preferably 14 parts by weight or less, per 100 parts by weight of the acrylic polymer.

[0102] The surface hardness of the pressure-sensitive adhesive layer 15 tends to increase as the amount of crosslinking agent used increases, but if the amount of crosslinking agent used is increased too much, the amount of unreacted crosslinking agent tends to increase. Because the unreacted crosslinking agent functions as a plasticizer, if the amount of crosslinking agent used is increased too much, the surface hardness of the pressure-sensitive adhesive layer 15 tends to decrease.

[0103] To achieve a surface hardness of the pressure-sensitive adhesive layer 15 within the first or second range and to prevent contamination of the antifouling layer 12 caused by the crosslinking agent, it is preferable to adjust the ratio of the crosslinkable functional groups of the acrylic polymer to the reactive functional groups of the crosslinking agent within an appropriate range. The amount of crosslinking agent added is preferably adjusted so that the molar equivalent of the reactive functional groups of the crosslinking agent is 0.2 to 1.2 times the molar equivalent of the crosslinkable functional groups of the acrylic polymer. For example, when an isocyanate-based crosslinking agent is used, it is preferable to adjust the amount of crosslinking agent so that the molar equivalent of the isocyanate groups is 0.2 to 1.2 times the molar equivalent of the hydroxy groups of the acrylic polymer. When an epoxy-based crosslinking agent is used, it is preferable to adjust the amount of crosslinking agent so that the molar equivalent of the epoxy groups is 0.2 to 1.2 times the molar equivalent of the carboxy groups of the acrylic polymer. The molar equivalent of the reactive functional groups of the crosslinking agent is more preferably 0.2 to 1.0 times the molar equivalent of the crosslinkable functional groups of the acrylic polymer.

[0104] The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 15 contains a base polymer and, if necessary, a crosslinking agent and a solvent. The pressure-sensitive adhesive composition may contain additives such as a polymerization catalyst, a crosslinking catalyst, a silane coupling agent, a tackifier, a plasticizer, a softener, an antidegradant, a filler, a colorant, an ultraviolet absorber, an antioxidant, a surfactant, and an antistatic agent, within a range that does not impair the properties of the present invention.

[0105] The pressure-sensitive adhesive composition is applied to a film that will become the base layer 14 by roll coating, kiss roll coating, gravure coating, reverse coating, roll brush, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, die coating, or the like, and the solvent is dried and removed as necessary to form the pressure-sensitive adhesive layer 15. Any appropriate drying method can be used. The drying temperature is preferably 40°C or higher and 200°C or lower, more preferably 50°C or higher and 180°C or lower. The drying time is preferably 5 seconds or higher and 20 minutes or lower, more preferably 5 seconds or higher and 10 minutes or lower.

[0106] When the pressure-sensitive adhesive composition contains a crosslinking agent, it is preferable to promote crosslinking by heating or aging simultaneously with or after drying of the solvent. When the pressure-sensitive adhesive composition contains a constituent monomer component of the base polymer, it is preferable to carry out polymerization by heating or aging. The heating temperature and heating time are appropriately set depending on the type of monomer or crosslinking agent used, and for example, the heating temperature is in the range of 20°C to 160°C, and the heating time is in the range of 1 minute to 7 days. The heating for drying and removing the solvent may also serve as the heating for polymerization or crosslinking.

[0107] [Preferred embodiment of optical laminate A] In this embodiment, in order to enhance the antifouling properties while further suppressing the generation of air bubbles and adhesive residue, it is preferable that the optical laminate A satisfies the following condition 1, more preferably the following condition 2, and even more preferably the following condition 3. Condition 1: The surface hardness of the main surface of the pressure-sensitive adhesive layer on the side of the antifouling layer is 0.30 MPa or more and 3.00 MPa or less, and the antifouling layer is a vacuum-deposited film. Condition 2: The above condition 1 is satisfied, and the thickness of the adhesive layer is 5 μm or more and 50 μm or less. Condition 3: The above condition 2 is satisfied, and the surface hardness of the main surface of the pressure-sensitive adhesive layer on the antifouling layer side is greater than 0.60 MPa.

[0108] [Other embodiments] Although the optical laminate with a surface protective film according to this embodiment has been described above, the present invention is not limited to the above-described embodiment. For example, the optical laminate with a surface protective film according to the present invention may not include a primer layer and an antireflection layer. Furthermore, the optical laminate with a surface protective film according to the present invention may include an optical functional layer different from the layers included in the above-described configuration. [Example]

[0109] Examples of the present invention will be described below, but the present invention is not limited to the following examples.

[0110] <Preparation of Optical Laminate of Example 1> Hereinafter, a description will be given of a method for producing the optical laminate of Example 1. First, a method for producing the antireflection film will be described.

[0111] [Preparation of anti-reflection film] (Hard Coat Layer Forming Process) 100 parts by weight (solid content equivalent) of a urethane acrylate-based ultraviolet-curable resin composition containing silica particles with a number-average primary particle diameter of 50 nm ("Beamset 577" manufactured by Arakawa Chemical Industries, Ltd.), 0.4 parts by weight of silicone resin particles ("Tospearl 130" manufactured by Momentive Performance Materials Japan, Inc., average particle diameter: 3.0 μm, refractive index: 1.43, true specific gravity: 1.32), 0.5 parts by weight of cross-linked polymethyl methacrylate (PMMA) particles ("Techpolymer SSX-103" manufactured by Sekisui Plastics Co., Ltd., average particle diameter: 3.0 μm, refractive index: 1.50, true specific gravity: 1.20), 2.0 parts by weight of a thixotropic agent ("Sumecton SAN" manufactured by Kunimine Industries Co., Ltd., a synthetic smectite which is an organic clay), and a photopolymerization initiator (IGM 1.5 parts by weight of a silicone leveling agent ("Omnirad127" manufactured by Resins Co., Ltd.) and 0.15 parts by weight of a silicone leveling agent ("Polyflow LE303" manufactured by Kyoeisha Chemical Co., Ltd.) were mixed and diluted with butyl acetate to obtain a hard coat layer-forming composition HC1 with a solids concentration of 42% by weight. Next, the hard coat layer-forming composition HC1 obtained by the above procedure was applied to one main surface of a transparent TAC film ("Fujitac TG60UL" manufactured by Fujifilm Corporation, thickness: 60 μm) to form a coating film. Next, this coating film was dried by heating at a temperature of 60°C for 60 seconds, and then cured by ultraviolet irradiation. For ultraviolet irradiation, a high-pressure mercury lamp was used as the light source, with ultraviolet light of 365 nm and an integrated light dose of 300 mJ / cm. 2 As a result, a hard coat layer with a thickness of 6 μm was formed on the TAC film.

[0112] (Surface modification process of hard coat layer) Next, the surface of the hard coat layer was plasma treated using a roll-to-roll plasma treatment device while transporting the TAC film (transparent film substrate) on which the hard coat layer had been formed, in a vacuum atmosphere of 0.5 Pa. During the plasma treatment, argon gas was used as the inert gas, and the effective power density was 0.02 W·min / cm. 2·m. As a result, a laminate (hereinafter, sometimes referred to as "optical film F1") comprising a TAC film and a plasma-treated hard coat layer was obtained. The effective power density is the power density (W / cm 2 ) divided by the film transport speed (m / min) using the roll-to-roll method.

[0113] Next, the primer layer forming process and the anti-reflection layer forming process will be described. In the primer layer forming process and the anti-reflection layer forming process, when forming (depositing) the oxide film, argon gas and oxygen gas were introduced into the film forming chamber. When forming (depositing) the oxide film, the pressure was kept constant by adjusting the introduction and exhaustion amounts of argon gas, and the introduction amount of oxygen gas was adjusted by plasma emission monitoring (PEM) control so that the film formation mode remained in the transition region.

[0114] (Primer layer formation process) The optical film F1 obtained by the above procedure was introduced into a roll-to-roll sputtering deposition apparatus, and the deposition chamber was filled with 1×10 -4 The pressure was reduced to 10 Pa. Next, while transporting the optical film F1, the surface temperature of the film-forming roll was reduced to -8°C, and a 3.5 nm thick SiOx layer (x<2) was formed (deposited) as a primer layer on one main surface of the hard coat layer by reactive sputtering. A Si target was used as the target material for forming the primer layer.

[0115] (Anti-reflection layer formation process) Following the formation of the primer layer, a roll-to-roll sputtering deposition apparatus was used to transport the optical film F1 after the primer layer formation. The following layers were then deposited, in this order, on one main surface of the primer layer by reactive sputtering: a first layer: a 10.1 nm thick niobium oxide layer (refractive index: 2.33), a second layer: a 27.5 nm thick silicon oxide layer (refractive index: 1.46), a third layer: a 105.0 nm thick niobium oxide layer, and a fourth layer: an 83.5 nm thick silicon oxide layer. A Si target was used to deposit the silicon oxide layer, and a Nb target was used to deposit the niobium oxide layer. This resulted in a four-layer antireflection layer (consisting of a first layer, a second layer, a third layer, and a fourth layer) on one main surface of the primer layer.

[0116] (Anti-fouling layer formation process) A coating agent ("SHIN-ETSU SUBELYN KY1903-1" manufactured by Shin-Etsu Chemical Co., Ltd., active ingredient (antifouling agent): an alkoxysilane compound containing a perfluoropolyether skeleton) was dried and solidified and used as a vapor deposition source. The vapor deposition source was heated to a temperature of 260°C, and an 8-nm-thick antifouling layer was formed on the antireflection layer by vacuum vapor deposition. This resulted in an antireflection film AR1 comprising, in this order, a TAC film, a hard coat layer, a primer layer, an antireflection layer, and an antifouling layer.

[0117] [Preparation of surface protection film] (Preparation of Pressure-Sensitive Adhesive Composition PS1) A reaction vessel equipped with a thermometer, stirrer, condenser, and nitrogen gas inlet tube was charged with 100 parts by weight of 2-ethylhexyl acrylate as monomer components, 80 parts by weight of vinyl acetate, and 5 parts by weight of acrylic acid, as well as 0.3 parts by weight of a polymerization initiator (NOF Corporation's "Niper BW") and 2,400 parts by weight of toluene. The contents of the vessel were maintained at a temperature of 23°C, and nitrogen gas was introduced while stirring to perform nitrogen substitution. The temperature of the contents of the vessel was then maintained at 65°C, and a polymerization reaction was carried out for 6 hours. The temperature of the contents of the vessel was then raised to 95°C and maintained at 95°C for 8 hours. The contents of the vessel were then cooled to obtain a solution of an acrylic polymer with a weight-average molecular weight of 470,000 (solids concentration: 38% by weight). To 100 parts by weight (solids content) of the resulting acrylic polymer solution, 2 parts by weight of a tetrafunctional epoxy compound ("Tetrad C" manufactured by Mitsubishi Gas Chemical Company, Inc.) was added as a crosslinking agent, and the mixture was diluted with methyl ethyl ketone to obtain PSA composition PS1 with a solids content of 20% by weight. The molar equivalent of the epoxy groups in the crosslinking agent in PSA composition PS1 was 0.29 times the molar equivalent of the carboxyl groups in the polymer.

[0118] (Formation of adhesive layer) The pressure-sensitive adhesive composition PS1 was applied to the second main surface of a 38 μm-thick PET film (Diafoil T100G38, manufactured by Mitsubishi Chemical Corporation) whose first main surface had been antistatically treated, and dried for 2 minutes at 130° C. to form a 13 μm-thick pressure-sensitive adhesive layer. The release-treated surface of a release liner (a 25 μm-thick PET film with one side release-treated with a silicone-based release agent) was then attached to the exposed surface of the pressure-sensitive adhesive layer, to obtain a surface protection film SP1 protected by the release liner.

[0119] [Laminating surface protection film and anti-reflection film] After peeling the release liner from the surface protective film SP1, the pressure-sensitive adhesive layer of the surface protective film SP1 was attached to the surface of the antifouling layer of the antireflection film AR1 using a roll laminator, thereby obtaining the optical laminate of Example 1 (optical laminate with a surface protective film).

[0120] <Preparation of Optical Laminates of Examples 2 to 7> The optical laminates of Examples 2 to 7 were obtained in the same manner as in Example 1, except that the amount of a tetrafunctional epoxy compound ("Tetrad C" manufactured by Mitsubishi Gas Chemical Company, Inc.) added when preparing the adhesive composition was changed as follows relative to 100 parts by weight of the polymer. Note that, hereinafter, the adhesive compositions used in Examples 2 to 7 may be referred to as adhesive compositions PS2 to PS7, respectively.

[0121] [Addition amount of tetrafunctional epoxy compound in Examples 2 to 7] Example 2 (adhesive composition PS2): 4 parts by weight Example 3 (adhesive composition PS3): 6 parts by weight Example 4 (adhesive composition PS4): 8 parts by weight Example 5 (adhesive composition PS5): 10 parts by weight Example 6 (adhesive composition PS6): 12 parts by weight Example 7 (adhesive composition PS7): 14 parts by weight

[0122] <Preparation of Optical Laminate of Example 8> An optical laminate of Example 8 was obtained in the same manner as in Example 1, except that pressure-sensitive adhesive composition PS8 was used instead of pressure-sensitive adhesive composition PS1 and the thickness of the pressure-sensitive adhesive layer was changed to 23 μm. The pressure-sensitive adhesive composition PS8 was prepared as follows.

[0123] [Preparation of Pressure-Sensitive Adhesive Composition PS8] A reaction vessel equipped with a thermometer, stirrer, condenser, and nitrogen gas inlet tube was charged with 96 parts by weight of 2-ethylhexyl acrylate and 4 parts by weight of 2-hydroxyethyl acrylate as monomer components, 0.2 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator, and 150 parts by weight of ethyl acetate. The contents of the vessel were maintained at a temperature of 23°C, and nitrogen gas was introduced while stirring to replace the atmosphere. The temperature of the contents of the vessel was then maintained at 65°C, allowing the polymerization reaction to proceed for 6 hours, yielding an acrylic polymer solution (solids concentration: 40% by weight). 250 parts by weight of the resulting acrylic polymer solution (100 parts by weight of polymer) was diluted to a concentration of 30% by weight with 73 parts by weight of toluene and 10 parts by weight of acetylacetone. To this solution was added 1.3 parts by weight (1.0 part by weight as solids) of a 75% by weight ethyl acetate solution of tolylene diisocyanate trimer adduct of trimethylolpropane ("Coronate L" manufactured by Tosoh Corporation) as a crosslinking agent, and 4 parts by weight (0.02 part by weight as solids) of a 0.5% by weight solution of dioctyltin laurate ("Envirizer OL-1" manufactured by Tokyo Fine Chemical Co., Ltd.) as a crosslinking catalyst, followed by stirring to obtain PSA composition PS8. The molar equivalent of the isocyanate groups in the crosslinking agent in PSA composition PS8 was 0.69 times the molar equivalent of the hydroxyl groups in the polymer.

[0124] <Preparation of Optical Laminate of Comparative Example 1> An optical laminate of Comparative Example 1 was obtained in the same manner as in Example 8, except that pressure-sensitive adhesive composition PS9 was used instead of pressure-sensitive adhesive composition PS8. Pressure-sensitive adhesive composition PS9 was obtained in the same manner as pressure-sensitive adhesive composition PS8, except that the amount of crosslinking agent (75 wt % ethyl acetate solution of tolylene diisocyanate trimer adduct of trimethylolpropane) added was changed to 5.3 parts by weight (4.0 parts by weight as solid content).

[0125] <Preparation of Optical Laminate of Comparative Example 2> An optical laminate of Comparative Example 2 was obtained in the same manner as in Example 8, except that pressure-sensitive adhesive composition PS10 was used instead of pressure-sensitive adhesive composition PS8 and the thickness of the pressure-sensitive adhesive layer was changed to 21 μm. Pressure-sensitive adhesive composition PS10 was obtained in the same manner as pressure-sensitive adhesive composition PS8, except that the crosslinking agent and the amount thereof added were changed to 17.58 parts by weight of an isocyanurate of hexamethylene diisocyanate ("Coronate HX" manufactured by Tosoh Corporation).

[0126] <Preparation of Optical Laminate of Comparative Example 3> An optical layered body of Comparative Example 3 was obtained in the same manner as in Example 8, except that the antifouling layer forming step was changed as follows.

[0127] [Anti-fouling layer forming step of Comparative Example 3] A coating agent ("SHIN-ETSU SUBELYN KY1903-1" manufactured by Shin-Etsu Chemical Co., Ltd., active ingredient (antifouling agent): alkoxysilane compound containing a perfluoropolyether skeleton) was applied to the antireflection layer to form a coating film. The coating film was then dried by heating at 60°C for 60 seconds, forming an 8 nm thick antifouling layer on the antireflection layer.

[0128] <Preparation of Optical Laminate of Comparative Example 4> An optical layered body of Comparative Example 4 was obtained in the same manner as in Comparative Example 1, except that the antifouling layer forming step was changed to the same method as in the above [Antifouling layer forming step of Comparative Example 3].

[0129] <Measurement and evaluation methods> The following describes the methods for measuring the surface hardness of the pressure-sensitive adhesive layer of the surface protection film used to prepare each optical laminate, the physical properties of each optical laminate, and the evaluation methods for each optical laminate. The measurements and evaluations described below were carried out in an environment of a temperature of 23°C and a relative humidity of 50%, unless otherwise specified.

[0130] [Surface hardness of adhesive layer] After peeling off the release liner, each surface protection film was fixed with the adhesive layer facing upward on the stage of a nanoindenter (Bruker TI950 TriboIndenter). Next, a Berkovich (triangular pyramid) diamond indenter (tip curvature radius: 0.1 μm) was used to gradually apply a load to the main surface of the adhesive layer (the surface to be bonded to the antifouling layer). The indentation hardness (indentation load / projected contact area between the indenter and the sample) was calculated when the indenter was pressed to a depth of 4000 nm, and the resulting value was used as the surface hardness of the adhesive layer. The projected contact area between the indenter and the sample was calculated using the method described in JP 2005-195357 A.

[0131] [Water contact angle] Using a contact angle measuring device ("DMo-701" manufactured by Kyowa Interface Science Co., Ltd.), 4.0 μL of water was dropped onto the surface of the antifouling layer of each optical laminate (the main surface to which the surface protective film was to be attached) before the surface protective film was attached, and the angle between the antifouling layer surface and the tangent to the end of the droplet was measured 2 seconds after the dropping.

[0132] [Oleic acid sliding test] First, a weight was attached above the sliding part of a linear abrasion tester ("5800" manufactured by Taber Industries) so that the total load during sliding was 2.5 kg. Next, the main surface of each optical laminate (before the surface protective film was attached) on the transparent film substrate side was attached to a glass plate, and 1 mL of oleic acid (manufactured by Hayashi Pure Chemical Industries, Ltd.) was dropped onto the antifouling layer. Next, the position of the sliding part, to which a paper towel ("C-Fold Paper Towels" manufactured by Kimberly-Clark) was attached, was adjusted so that the tip of the sliding part came into contact with the area on the antifouling layer surface where the oleic acid had been dropped. Next, an oleic acid sliding test was performed, with the sliding distance (one way in reciprocating motion) of the tip of the sliding part on the antifouling layer surface set to 40 mm, the sliding speed of the tip of the sliding part set to 60 reciprocations / min, and the number of reciprocating motions of the tip of the sliding part against the antifouling layer surface set to 1,000. Next, the water contact angle of the antifouling layer surface (sliding surface) after the oleic acid sliding test was measured using the method described above in the section "Water Contact Angle." If the water contact angle after the oleic acid sliding test was 90° or more, it was evaluated as A (excellent antifouling property). On the other hand, if the water contact angle after the oleic acid sliding test was less than 90°, it was evaluated as B (not excellent antifouling property).

[0133] [Autoclave test] The main surface of each optical laminate on the transparent film substrate side was attached to a glass plate, and then treated for 15 minutes in an autoclave set at a temperature of 50°C and a pressure of 0.5 MPa. Each optical laminate was then left to stand for 30 minutes in an environment of a temperature of 23°C and a relative humidity of 50%, and the presence or absence of bubbles at the interface between the surface protective film and the antifouling layer was visually confirmed. If no bubbles were observed, the result was evaluated as A (bubble generation suppressed). On the other hand, if bubbles were observed, the result was evaluated as B (bubble generation not suppressed).

[0134] [Adhesion strength] Each optical laminate was cut into a width of 50 mm and a length of 100 mm, and left to stand for 30 minutes in an environment of 23°C and 50% relative humidity, after which the main surface of each optical laminate on the transparent film substrate side was attached to an acrylic plate using double-sided adhesive tape to obtain a measurement sample. Next, the surface protection film at one end of the measurement sample in the longitudinal direction was peeled off, and a peel test was performed under conditions of a peel angle of 180° and a tensile speed of 0.3 m / min, and the obtained peel strength was defined as the adhesion strength between the antifouling layer and the adhesive layer (unit: N / 50 mm).

[0135] <Result> For the optical laminates of Examples 1 to 8 and Comparative Examples 1 to 4, the type of pressure-sensitive adhesive composition used, the surface hardness of the pressure-sensitive adhesive layer, the thickness of the pressure-sensitive adhesive layer, the method for forming the antifouling layer, the water contact angle, the evaluation results of the oleic acid sliding test, the evaluation results of the autoclave test, and the adhesion strength are shown in Table 1. In Table 1, "water contact angle" means the water contact angle of the antifouling layer before the oleic acid sliding test. In Table 1, "adhesion strength" means the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer.

[0136] [Table 1]

[0137] As shown in Table 1, in Examples 1 to 8, the surface hardness of the pressure-sensitive adhesive layer was 0.01 MPa or more and 0.05 MPa or less, or 0.30 MPa or more and 3.00 MPa or less. In Examples 1 to 8, the water contact angle of the antifouling layer before the oleic acid sliding test was 115° or more. In Examples 1 to 8, the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer was 0.01 N / 50 mm or more and 0.15 N / 50 mm or less.

[0138] As shown in Table 1, in Examples 1 to 8, the evaluation results of the oleic acid sliding test were A. Therefore, the optical laminates of Examples 1 to 8 were excellent in antifouling property. In Examples 1 to 8, the evaluation results of the autoclave test were A. Therefore, the optical laminates of Examples 1 to 8 were suppressed in the generation of bubbles.

[0139] As shown in Table 1, the surface hardness of the PSA layer was greater than 0.05 MPa and less than 0.30 MPa in Comparative Examples 1, 2, and 4. In Comparative Examples 3 and 4, the water contact angle of the antifouling layer before the oleic acid sliding test was less than 115°.

[0140] As shown in Table 1, the evaluation results of the oleic acid sliding test for Comparative Examples 3 and 4 were B. Therefore, the optical laminates of Comparative Examples 3 and 4 did not have excellent antifouling properties. The evaluation results of the autoclave test for Comparative Examples 1 and 2 were B. Therefore, the optical laminates of Comparative Examples 1 and 2 did not suppress bubble generation.

[0141] Regarding the optical laminates of Examples 1 to 8 and Comparative Examples 1 to 4, when the surfaces of the antifouling layers were visually inspected after measuring the adhesion strength, no adhesive residue was found on the surfaces of the antifouling layers.

[0142] The above results demonstrate that the present invention can provide an optical laminate with a surface protective film that can improve antifouling properties while suppressing the generation of bubbles and adhesive residue. [Explanation of symbols]

[0143] 10: Optical laminate 11: Transparent film substrate 12: Antifouling layer 13: Surface protection film 14: Base material layer 15: Adhesive layer 16:Transparent film 17: Hard coat layer 20: Anti-reflection layer 25: Primer layer

Claims

1. An optical laminate with a surface protective film, comprising a transparent film substrate, an antifouling layer, and a surface protective film in this order, the surface protection film has a base layer and a pressure-sensitive adhesive layer, the antifouling layer and the pressure-sensitive adhesive layer are in contact with each other, the surface hardness of the main surface of the pressure-sensitive adhesive layer on the antifouling layer side is 0.01 MPa or more and 0.05 MPa or less, or 0.30 MPa or more and 3.00 MPa or less; the water contact angle of the main surface of the antifouling layer on the pressure-sensitive adhesive layer side is 115° or more; An optical laminate with a surface protective film, wherein the adhesion strength between the antifouling layer and the pressure-sensitive adhesive layer is 0.01 N / 50 mm or more and 0.15 N / 50 mm or less.

2. 2. The optical laminate with a surface protective film according to claim 1, wherein the surface hardness of the main surface of the pressure-sensitive adhesive layer on the antifouling layer side is 0.30 MPa or more and 3.00 MPa or less.

3. The optical laminate with a surface protective film according to claim 1 , wherein the antifouling layer is a vacuum-deposited film.

4. The optical laminate with a surface protective film according to claim 1 , wherein the pressure-sensitive adhesive layer has a thickness of 5 μm or more and 50 μm or less.

5. the transparent film substrate includes a transparent film and a hard coat layer provided on a first main surface side of the transparent film; The optical laminate with a surface protective film according to claim 1 , wherein the antifouling layer is provided on the hard coat layer side of the transparent film substrate.

6. The optical laminate with a surface protective film according to claim 1 , further comprising an antireflection layer provided between the transparent film substrate and the antifouling layer.

7. The optical laminate with a surface protective film according to claim 6 , further comprising a primer layer provided between the transparent film substrate and the antireflection layer.

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