Laminate, laminated film, image display device, and foldable device

Abstract

The present invention addresses the problem of providing a laminate capable of exhibiting sufficient bendability without using a compound corresponding to PFAS. [Solution] A laminate according to the present disclosure has a base material and a hard coat layer laminated on at least one surface of the base material, the hard coat layer does not contain a compound corresponding to PFAS, and the laminate is characterized by having a minimum bendable radius of 5 mm or less in a cylindrical mandrel test in which the surface of the hard coat layer of the laminate is bent so as to be convex. In addition, the number of actions of the hard coating layer until the hard coating layer cracks in a bending durability test is preferably 10,000 or more.

Description

Technical Field

[0001] The present disclosure relates to a laminate, a laminated film, an image display device, and a foldable device. Background Art

[0002] As a covering material used on the outermost surface of displays such as televisions, personal computers, and smartphones, and electronic materials, a configuration in which a hard coat is laminated to prevent damage is known. In particular, in order to make such a hard coat exhibit abrasion resistance, a UV-curable resin containing a crosslinkable fluorine compound (PFAS) has been conventionally used (for example, Patent Document 1).

[0003] On the other hand, PFAS lacks degradability, and the problems of long-term residue and toxicity in the environment have been widely discussed. From the viewpoint of reducing the environmental load, a hard coat not containing PFAS is required.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2016-11365 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] However, in a hard coat that does not use PFAS, the flexibility is insufficient, and it is difficult to produce a hard coat that exhibits the same flexibility as a product containing PFAS.

[0009] The present disclosure has been made to solve the above problems, and an object thereof is to provide a laminate that can exhibit sufficient flexibility without using a compound equivalent to PFAS.

[0010] Means for Solving the Problems

[0011] The inventors of the present disclosure have found that as long as it is a laminate having a substrate and a hard coat laminated on at least one surface of the substrate, the hard coat does not contain a compound equivalent to PFAS, and satisfies specific physical property values, sufficient flexibility can be exhibited without using a fluorine compound. The present disclosure has been completed based on these insights.

[0012] The present disclosure provides a laminate having a substrate and a hard coat laminated on at least one surface of the substrate, the hard coat not containing a compound equivalent to PFAS, and in a cylindrical mandrel test in which the laminate is bent in such a manner that the surface of the hard coat of the laminate becomes convex, the minimum radius at which it can be bent is 5 mm or less.

[0013] Preferably, in the following bending durability test of the above laminate, the number of operations until cracks occur in the hard coat is 10,000 or more. By having the above configuration, the bending durability can be made more excellent.

[0014] Bending durability test:

[0015] Starting from the state after stretching the laminate, the laminate is bent 180° in such a way that the bending radius is 4.0 mm in the direction where the surface of the hard coat becomes convex, the laminate is stretched again, and this operation is defined as one time, and the operation is performed at a speed of 30 to 60 times per minute.

[0016] Preferably, for the above laminate, while applying a load of 750 g / cm with #0000 steel wool on the above hard coat, the surface of the above hard coat is reciprocally rubbed 1000 times in the wire wool resistance test, and no damage is visually observed. By having the above configuration, the scratch resistance can be made more excellent. 2 Preferably, for the above laminate, the haze of the above hard coat is 1.0% or less.

[0017] Preferably, for the above laminate, the haze of the above laminate is 7% or less.

[0018] In addition, preferably, the above hard coat is a cured product of a curable composition containing one or more curable compounds, and polyorganosilsesquioxane is included as the above curable compound.

[0019] In addition, preferably, the above curable composition contains a compound having one or more cationic polymerizable groups and one or more radical polymerizable groups in the molecule.

[0020] Preferably, the above curable composition further contains a curing catalyst.

[0021] Preferably, the above curing catalyst contains a cationic polymerization initiator.

[0022] Preferably, the above curing catalyst contains a radical polymerization initiator.

[0023] Preferably, the above curable composition further contains a radically curable polyorganosiloxane.

[0024] Preferably, the above curable composition further contains an aliphatic compound having two or more cationic polymerizable groups in the molecule.

[0025] Preferably, the above substrate is a transparent substrate.

[0026] Preferably, the above laminate has a surface protective film on at least one surface.

[0027] Preferably, the above laminate has a surface protective film on at least one surface.

[0028] Preferably, the above laminate has the above hard coat on one surface of the above substrate and an adhesive layer on the other surface.

[0029] In addition, the present disclosure provides an image display device including the above laminate.

[0030] Preferably, the above image display device is a foldable display.

[0031] Preferably, the above image display device is an organic electroluminescent display device.

[0032] In addition, the present disclosure provides a foldable device including the above image display device.

[0033] Advantageous Effects of the Invention

[0034] The laminate of the present disclosure can exhibit sufficient flexibility without using a compound equivalent to PFAS. Detailed Description of Embodiments

[0035] It should be noted that in the present disclosure, the "compound equivalent to PFAS" is a general term for perfluoroalkyl compounds and polyfluoroalkyl compounds.

[0036] [Laminate]

[0037] The laminate of the present disclosure has a substrate and a hard coat laminated on at least one surface of the above substrate. The above hard coat does not contain a compound equivalent to PFAS. In the cylindrical mandrel test in which the laminate is bent in such a manner that the surface of the hard coat of the laminate becomes convex, the minimum radius at which it can be bent is 5 mm or less. The laminate of the present disclosure having the above configuration can exhibit sufficient flexibility without containing a compound equivalent to PFAS.

[0038] The above laminate may also have other layers in addition to the above substrate and the above hard coat. Examples of the above other layers include a surface protective film, an adhesive layer, a primer layer for bonding the substrate and the hard coat, an antireflection layer, an antiglare layer, a fingerprint-resistant layer, an antifouling layer, a friction-resistant fingerprint layer, an antibacterial layer, a bonding layer, a polarizing layer, etc. The above other layers may be formed only on one surface (single-sided) of the above substrate, or may be formed on both surfaces (double-sided). In addition, when the above other layers are formed on both surfaces of the above substrate, the same layers may be laminated respectively, or layers having different thicknesses and compositions may be laminated respectively.

[0039] The above surface protective film is a film for protecting the surface of the above hard coat. The laminate preferably has a surface protective film on at least one surface. In addition, in the case where the hard coat is formed on both surfaces of the above substrate, etc., the laminate may also have the above surface protective film on both surfaces of the laminate.

[0040] As the above-mentioned surface protective film, a publicly known or commonly used surface protective film can be used, and there is no particular limitation. For example, a surface protective film having an adhesive layer on the surface of a plastic film can be used. As the above-mentioned plastic film, for example, those formed of plastic materials such as polyester (polyethylene terephthalate, polyethylene naphthalate, etc.), polyolefin (polyethylene, polypropylene, cyclic polyolefin, etc.), polystyrene, acrylic resin, polycarbonate, epoxy resin, fluororesin, silicone resin, diacetate resin, triacetate resin, polyarylate, polyvinyl chloride, polysulfone, polyethersulfone, polyetheretherimide, polyimide, polyamide, etc. can be cited. As the above-mentioned adhesive layer, for example, an adhesive layer formed of one or more of publicly known or commonly used adhesives such as acrylic adhesives, silicone adhesives, natural rubber adhesives, synthetic rubber adhesives, ethylene-vinyl acetate copolymer adhesives, ethylene-(meth)acrylate copolymer adhesives, styrene-isoprene block copolymer adhesives, styrene-butadiene block copolymer adhesives, etc. can be cited. In the above-mentioned adhesive layer, various additives (for example, antistatic agents, slip agents, etc.) can be contained. It should be noted that the plastic film and the adhesive layer can each have a single-layer structure or can each have a multi-layer (plural-layer) structure. In addition, the thickness of the surface protective film is not particularly limited and can be appropriately selected.

[0041] As the above-mentioned surface protective film, for example, the following commercially available products can be obtained: products of the trade name "SUNYTECT" series (manufactured by Sun A Kaken Co., Ltd.), products of the trade name "E-MASK" series (manufactured by Nitto Denko Corporation), products of the trade name "MASTACK" series (manufactured by Fujimori Kogyo Co., Ltd.), products of the trade name "HITALEX" series (manufactured by Hitachi Chemical Co., Ltd.), products of the trade name "ALPHAN" series (manufactured by Oji F-Tex Co., Ltd.), etc.

[0042] The above-mentioned adhesive layer is preferably laminated on the surface of the above-mentioned substrate opposite to the surface on which the hard coat is laminated in the above-mentioned laminate. That is, when the above-mentioned laminate has the above-mentioned adhesive layer, it is preferable that the above-mentioned hard coat is provided on one surface of the above-mentioned substrate and the above-mentioned adhesive layer is provided on the other surface. In addition, it is more preferable that the above-mentioned laminate has the above-mentioned adhesive layer on the surface of one side.

[0043] As the adhesive constituting the above-mentioned adhesive layer, the same adhesives as those exemplified in the above-mentioned surface protective film can be used. Among them, from the viewpoints of good transparency and sufficient adhesiveness even when thin, acrylic adhesives and silicone adhesives are preferred, and acrylic adhesives are particularly preferred. It should be noted that the above-mentioned adhesive can be used alone or two or more kinds can be used.

[0044] The thickness of the above-mentioned adhesive layer is, for example, 0.1 to 50 μm, preferably 1 to 45 μm, more preferably 2 to 40 μm, and further preferably 5 to 35 μm.

[0045] The above-mentioned adhesive layer can be obtained by applying the above-mentioned adhesive to at least one surface of the substrate and curing it.

[0046] In the cylindrical mandrel test conducted in accordance with JIS K5600-5-1, where the hard coat surface is convex, the minimum bending diameter without cracks in the above-mentioned laminate is in the range of 5 mm or less, preferably 4 mm or less. By having the minimum bending diameter of 5 mm or less, sufficient bendability can be exhibited. It should be noted that in the case where hard coats are laminated on both sides of the above-mentioned laminate, it is sufficient if at least one surface satisfies the above range.

[0047] Similarly, in the cylindrical mandrel test conducted in accordance with JIS K5600-5-1, where the hard coat surface is concave, the minimum bending diameter without cracks in the above-mentioned laminate is preferably in the range of 5 mm or less, more preferably 4 mm or less, and further preferably 2 mm or less. By having the minimum bending diameter of 5 mm or less, sufficient bendability can be exhibited. It should be noted that in the case where hard coats are laminated on both sides of the above-mentioned laminate, it is sufficient if at least one surface satisfies the above range.

[0048] The pencil hardness of the above-mentioned laminate measured in accordance with JIS K5600-5-4 is preferably F or higher, more preferably H or higher. By making the pencil hardness F or higher, the surface hardness of the laminate becomes sufficient, and abrasion resistance is easily exhibited. It should be noted that in the case where hard coats are laminated on both sides of the above-mentioned laminate, it is sufficient if at least one surface satisfies the above range.

[0049] In the bending durability test of the above-mentioned laminate, the number of operations until cracks occur in the hard coat is preferably 10,000 times or more, more preferably 30,000 times or more without cracks. Bending durability test: Starting from the state after stretching the laminate, the laminate is bent 180° in the direction where the hard coat surface is convex with a bending radius of 4.0 mm, the laminate is stretched again, and this operation is defined as one time, and the above operation is performed at a speed of 30 to 60 times per minute. By having the above configuration, sufficient bending durability can be exhibited. It should be noted that in the case where hard coats are laminated on both sides of the above-mentioned laminate, it is sufficient if at least one surface satisfies the above range.

[0050] In addition, the above-mentioned laminate preferably shows no damage on the hard coat surface when #0000 steel wool reciprocates 1000 times on the hard coat surface with a load of 750 g / cm 2 By having the above configuration, abrasion resistance can be exhibited.

[0051] The haze value of the above-mentioned laminate is preferably 7% or less, more preferably 5% or less, still more preferably 3% or less, and particularly preferably 1.5% or less. It should be noted that the lower limit of the haze is, for example, 0.1%. By setting the haze to 7% or less, there is a tendency to be suitable for applications requiring high transparency. It should be noted that in this specification, the haze can be measured according to JIS K7136.

[0052] The total light transmittance of the above-mentioned laminate is preferably 85% or more, more preferably 90% or more. By setting the total light transmittance to 85% or more, there is a tendency to be suitable for applications requiring high transparency. It should be noted that in this specification, the total light transmittance can be measured according to JIS K7361-1.

[0053] The thickness of the above-mentioned laminate is preferably 10 to 1000 μm, more preferably 30 to 500 μm, and particularly preferably 50 to 300 μm. By the thickness of the above-mentioned laminate being 10 μm or more, it is easy to make the surface hardness sufficient. In addition, by the thickness being 1000 μm or less, it is easy to exhibit sufficient flexibility.

[0054] <Substrate>

[0055] As the substrate in the laminate of the present disclosure, known or conventional substrates such as plastic substrates, metal substrates, ceramic substrates, semiconductor substrates, glass substrates, paper substrates, wood substrates (wooden substrates), substrates with a painted surface, etc. can be used. Among them, the above-mentioned substrate is preferably a transparent substrate, and preferably a plastic substrate. In addition, the above-mentioned substrate can have a single-layer structure or a multi-layer structure, can be composed of one material, or two or more materials can be used.

[0056] The plastic material constituting the above-mentioned plastic substrate is not particularly limited, and examples include: polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyimides; polycarbonates; polyamides; polyacetals; polyphenylene ethers; polyphenylene sulfides; polyethersulfones; polyetheretherketones; homopolymers of norbornene monomers (addition polymers, ring-opening polymers, etc.), copolymers of norbornene monomers and olefin monomers such as copolymers of norbornene and ethylene (addition polymers, ring-opening polymers, etc., such as cyclic olefin copolymers), and their derivatives such as cyclic polyolefins; vinyl polymers (such as acrylic resins such as polymethyl methacrylate (PMMA), polystyrene, polyvinyl chloride, acrylonitrile-styrene-butadiene resins (ABS resins), etc.); vinylidene polymers (such as polyvinylidene chloride, etc.); cellulose-based resins such as triacetyl cellulose (TAC); epoxy resins; phenolic resins; melamine resins; urea resins; maleimide resins; various plastic materials such as silicone.

[0057] Among them, as the above-mentioned plastic substrate, a substrate with excellent transparency and bending durability is preferably used, more preferably a polyester film (especially PET, PEN), a polyimide film, a cyclic olefin film, a polycarbonate film, a TAC film, a PMMA film, and further preferably a polyester film (especially PET, PEN), a polyimide film.

[0058] The above-mentioned substrate may contain other additives such as antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers, crystal nucleating agents, flame retardants, flame retardant aids, fillers, plasticizers, impact resistance improvers, reinforcing agents, dispersants, antistatic agents, foaming agents, antibacterial agents, etc. as needed. It should be noted that only one kind of additive may be used, or two or more kinds may be used.

[0059] Roughening treatment, adhesion promotion treatment, antistatic treatment, sandblasting treatment (sand cushion treatment), corona discharge treatment, plasma treatment, chemical etching treatment, water cushion treatment, flame treatment, acid treatment, alkali treatment, oxidation treatment, ultraviolet irradiation treatment, silane coupling agent treatment, etc., which are well-known or commonly used surface treatments, may be performed on a part or all of the surface of the above-mentioned substrate on the side where the hard coat is laminated. It should be noted that the above-mentioned plastic substrate may be an unstretched film, or a stretched film such as a uniaxially stretched film or a biaxially stretched film. It should be noted that as the substrate, commercially available products may also be used.

[0060] The thickness of the above-mentioned substrate is preferably, for example, 1 to 1000 μm, more preferably 5 to 500 μm, further preferably 10 to 400 μm, and particularly preferably 10 to 300 μm.

[0061] <Hard coat>

[0062] The above-mentioned hard coat preferably suppresses the generation of cracks in the above-mentioned laminate and has sufficient surface hardness even when it is formed on only one surface (single side) of the above-mentioned substrate in the above-mentioned laminate. In addition, the above-mentioned hard coat may also be formed on both surfaces (double sides) of the above-mentioned substrate, but when the above-mentioned laminate has the above-mentioned adhesive layer, it is preferably formed on only one surface of the above-mentioned substrate. It should be noted that when the hard coat is formed on both sides of the above-mentioned substrate, as long as the physical property values of the following hard coat are satisfied on at least one surface, the hard coats may be laminated with the same layers respectively, or layers with different thicknesses and compositions may be laminated respectively. In addition, a hard coat may be formed on one surface of the above-mentioned substrate, and the above-mentioned other layer may be formed on the other surface. From the viewpoint of suppressing the generation of cracks, preferably, the above-mentioned hard coat is formed on at least one surface of the above-mentioned substrate, and the above-mentioned hard coat or the above-mentioned other layer is formed on the other surface.

[0063] The above hard coat is preferably formed from a cured product of a curable composition containing one or more curable compounds. That is, the above curable composition preferably contains one or more curable compounds. The above curable compounds may be used alone or in combination of two or more.

[0064] Examples of the above curable compounds include: (meth)acrylate compounds, curable silicone compounds, epoxy compounds, melamine compounds, vinyl ether compounds, oxetane compounds, etc. Among them, a curable silicone compound is preferably included. As the above curable silicone compound, a silsesquioxane is particularly more preferably included, and a polyorganosilsesquioxane is particularly preferably included. By including the above polyorganosilsesquioxane, the above curable composition is less likely to shrink during curing, and thus a hard coat with more excellent abrasion resistance can be formed. In addition, examples of the above silsesquioxane include a free-radical polymerizable silsesquioxane, a cationic polymerizable silsesquioxane, etc. Among them, a cationic polymerizable silsesquioxane is preferably used, and the above cationic polymerizable silsesquioxane is more preferably a photo cationic polymerizable silsesquioxane.

[0065] The above free-radical polymerizable silsesquioxane has a free-radical polymerizable functional group in the molecule. Examples of the above free-radical polymerizable functional group include (meth)acryloyl, (meth)acrylamide group, vinyl, vinylthio group, etc.

[0066] The above cationic polymerizable silsesquioxane has a cationic polymerizable functional group in the molecule. Examples of the above cationic polymerizable functional group include epoxy group, oxetanyl group, vinyl ether group, vinylphenyl group, etc. Among them, from the viewpoint of being able to further improve the surface hardness of the hard coat, an epoxy group is preferred.

[0067] Examples of the above group containing an epoxy group include known or conventional groups having an ethylene oxide ring, and there is no particular limitation. From the viewpoints of the curability of the curable composition and the heat resistance of the hard coat, a group represented by the following formula (1a), a group represented by the following formula (1b), a group represented by the following formula (1c), and a group represented by the following formula (1d) are preferred, and a group represented by the following formula (1a) and a group represented by the following formula (1c) are more preferred, and a group represented by the following formula (1a) is further preferred.

[0068] [Chemical formula 1]

[0069]

[0070] [Chemical formula 2]

[0071]

[0072] [Chemical formula 3]

[0073]

[0074] [Chemical Formula 4]

[0075]

[0076] In the above formula (1a), R 1a represents a linear or branched alkylene group. Examples of the linear or branched alkylene group include linear or branched alkylene groups having 1 to 10 carbon atoms such as methylene, methylmethylene, dimethylmethylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, hexamethylene, and decamethylene. Among them, as R 1a , from the viewpoint of the curability of the curable composition, a linear alkylene group having 1 to 4 carbon atoms or a branched alkylene group having 3 or 4 carbon atoms is preferred, and ethylene, trimethylene, and propylene are more preferred, and ethylene and trimethylene are further preferred.

[0077] In the above formula (1b), R 1b represents a linear or branched alkylene group, and groups similar to R 1a can be exemplified. Among them, as R 1b , from the viewpoint of the curability of the curable composition, a linear alkylene group having 1 to 4 carbon atoms or a branched alkylene group having 3 or 4 carbon atoms is preferred, and ethylene, trimethylene, and propylene are more preferred, and ethylene and trimethylene are further preferred.

[0078] In the above formula (1c), R 1c represents a linear or branched alkylene group, and groups similar to R 1a can be exemplified. Among them, as R 1c , from the viewpoint of the curability of the curable composition, a linear alkylene group having 1 to 4 carbon atoms or a branched alkylene group having 3 or 4 carbon atoms is preferred, and ethylene, trimethylene, and propylene are more preferred, and ethylene and trimethylene are further preferred.

[0079] In the above formula (1d), R 1d represents a linear or branched alkylene group, and groups similar to R 1a can be exemplified. Among them, as R 1d , from the viewpoint of the curability of the curable composition, a linear alkylene group having 1 to 4 carbon atoms or a branched alkylene group having 3 or 4 carbon atoms is preferred, and ethylene, trimethylene, and propylene are more preferred, and ethylene and trimethylene are further preferred.

[0080] As R 1 in the formula (1), the one represented by the above formula (1a) and R1a A group that is an ethylene group [wherein, 2-(3,4-epoxycyclohexyl)ethyl].

[0081] As the above-mentioned cationically polymerizable sesquisiloxane, for example, a compound having a structural unit represented by the following formula (1) can be cited.

[0082] [R 1 SiO 3 / 2 (1)

[0083] The structural unit represented by the above formula (1) is usually a sesquisiloxane structural unit (so-called T unit) represented by [RSiO 3 / 2 . It should be noted that R in the above formula represents a hydrogen atom or a monovalent organic group, and the same applies hereinafter. The structural unit represented by the above formula (1) is formed by hydrolysis and condensation reaction of the corresponding hydrolyzable trifunctional silane compound. It should be noted that in this specification, a compound having the structural unit represented by the above formula (1) is sometimes referred to as "sesquisiloxane (X)". R in formula (1) 1 represents a group (monovalent group) containing the above-mentioned cationically polymerizable functional group.

[0084] Sesquisiloxane (X) may have only one kind of the structural unit represented by the above formula (1), or may have two or more kinds of the structural units represented by the above formula (1).

[0085] In sesquisiloxane (X), in addition to having the structural unit represented by the above formula (1) as the sesquisiloxane structural unit [RSiO 3 / 2 , it may also have the structural unit represented by the following formula (2) as the sesquisiloxane structural unit [RSiO 3 / 2 .

[0086] [R 2 SiO 3 / 2 (2)

[0087] The structural unit represented by the above formula (2) is usually a sesquisiloxane structural unit (T unit) represented by [RSiO 3 / 2 . That is, the structural unit represented by the above formula (2) is formed by hydrolysis and condensation reaction of the corresponding hydrolyzable trifunctional silane compound.

[0088] R in the above formula (2) 2Represents a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted cycloalkyl group, or a substituted or unsubstituted alkyl group. As the above-mentioned aryl group, for example, phenyl, tolyl, naphthyl, etc. can be cited. As the above-mentioned aralkyl group, for example, benzyl, phenethyl, etc. can be cited. As the above-mentioned cycloalkyl group, for example, cyclobutyl, cyclopentyl, cyclohexyl, etc. can be cited. As the above-mentioned alkyl group, for example, linear or branched alkyl groups such as methyl, ethyl, propyl, n-butyl, isopropyl, isobutyl, sec-butyl, tert-butyl, isopentyl, etc. can be cited.

[0089] As the above-mentioned substituted aryl group, substituted aralkyl group, substituted cycloalkyl group, and substituted alkyl group, those in which a hydrogen atom or a part or all of the main chain skeleton in each of the above-mentioned aryl group, aralkyl group, cycloalkyl group, and alkyl group is substituted with at least one selected from the group consisting of an alkyl group (especially a linear or branched alkyl group having 1 to 10 carbon atoms), an ether group, an ester group, a carbonyl group, a siloxanyl group, a halogen atom (such as a fluorine atom), a mercapto group, an amino group, and a hydroxyl group can be cited.

[0090] Among them, as R 2 , it is preferably a substituted or unsubstituted aryl group or a substituted or unsubstituted alkyl group, more preferably a substituted or unsubstituted aryl group, and further preferably a phenyl group.

[0091] The ratio of each of the above-mentioned silsesquioxane structural units (the structural unit represented by formula (1) and the structural unit represented by formula (2)) in the silsesquioxane (X) can be appropriately adjusted according to the composition of the raw materials (hydrolyzable trifunctional silanes) used for forming these structural units.

[0092] Among them, the silsesquioxane (X) preferably contains at least R 1 as the structural unit represented by the above formula (1) in which the group contains an alicyclic epoxy group, and R 2 as the structural unit represented by the above formula (2) in which the group is an aryl group that may have a substituent. In this case, there is a tendency for the surface hardness, flexibility, processability, and flame retardancy of the hard coat to be more excellent.

[0093] Alternatively, the silsesquioxane (X) may further have at least one siloxane structural unit selected from the group consisting of the structural unit represented by [R3SiO 1 / 2 (so-called M unit), the structural unit represented by [R2SiO 2 / 2 (so-called D unit), and the structural unit represented by [SiO 4 / 2 (so-called Q unit) in addition to the structural unit represented by the above formula (1) and the structural unit represented by the above formula (2) which are used as T units. It should be noted that R in the above M unit and the above D unit can be cited as the same as R in the structural unit represented by the above formula (1). 1and R in the structural unit represented by the above formula (2) 2 are the same group. As the silsesquioxane structural units other than the structural units represented by the above formula (1) and the structural units represented by the above formula (2), for example, the structural units represented by the following formula (3) etc. can be cited.

[0094] [HSiO 3 / 2 (3)

[0095] The silsesquioxane (X) contains the structural unit (T3 body) represented by the following formula (I). Moreover, it may also contain the structural unit (T2 body) represented by the following formula (II).

[0096] [R a SiO 3 / 2 (I)

[0097] [R b SiO 2 / 2 (OR c )](II)

[0098] It should be noted that if the structural unit represented by the above formula (I) is described in more detail, it is represented by the following formula (I'). In addition, if the structural unit represented by the above formula (II) is described in more detail, it is represented by the following formula (II'). The three oxygen atoms bonded to the silicon atom shown in the structure represented by the following formula (I') are respectively bonded to other silicon atoms (silicon atoms not shown in the formula (I')). On the other hand, the two oxygen atoms located above and below the silicon atom shown in the structure represented by the following formula (II') are respectively bonded to other silicon atoms (silicon atoms not shown in the formula (II')). That is, both the above T3 body and T2 body are structural units (T units) formed by the hydrolysis and condensation reaction of the corresponding hydrolyzable trifunctional silane compound.

[0099] [Chemical formula 5]

[0100]

[0101] [Chemical formula 6]

[0102]

[0103] R in the above formula (I) a (R in the formula (I') a is also the same) and R in the formula (II) b (R in the formula (II') b is also the same) respectively represent a group containing a cationic polymerizable functional group, a substituted or unsubstituted aryl group, a substituted or unsubstituted aralkyl group, a substituted or unsubstituted cycloalkyl group, a substituted or unsubstituted alkyl group, or a hydrogen atom. As R a and Rb Specific examples of which may include R in the above formula (1) 1 and R in the above formula (2) 2 The same groups. It should be noted that R in formula (I) a and R in formula (II) b are respectively groups derived from the groups bonded to the silicon atom in the hydrolyzable trifunctional silane compound used as the raw material of the silsesquioxane (X) (groups other than alkoxy groups and halogen atoms), or, for example, when the above cationic polymerizable functional group is an epoxy group, they are groups obtained by epoxidizing the groups bonded to the silicon atom in the hydrolyzable trifunctional silane compound used as the raw material of the silsesquioxane (X) (groups other than alkoxy groups and halogen atoms).

[0104] R in the above formula (II) c (R in formula (II') is the same) c represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of the alkyl group having 1 to 4 carbon atoms include linear or branched alkyl groups having 1 to 4 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, and isobutyl. Among them, methyl and ethyl are preferred, and methyl is more preferred. The alkyl group in R in formula (II) c usually originates from the alkyl group of the alkoxy group in the hydrolyzable silane compound used as the raw material of the silsesquioxane (X).

[0105] The molar ratio of the structural unit (T3 body) represented by the above formula (I) to the structural unit (T2 body) represented by the above formula (II) in the silsesquioxane (X) [structural unit represented by formula (I) / structural unit represented by formula (II)] (sometimes referred to as "T3 body / T2 body") is not particularly limited, preferably 5 or more, more preferably 5 to 20, further preferably 5 to 18, further preferably 6 to 16, further preferably 7 to 15, and particularly preferably 8 to 14. By setting the above molar ratio [T3 body / T2 body] to 5 or more, there is a tendency for the surface hardness of the hard coat to be further improved.

[0106] The above molar ratio [T3 body / T2 body] in the silsesquioxane (X) can be determined, for example, by 29 Si-NMR spectrum measurement. In the 29 Si-NMR spectrum, the silicon atoms in the structural unit (T3 body) represented by the above formula (I) and the silicon atoms in the structural unit (T2 body) represented by the above formula (II) show signals (peaks) at different positions (chemical shifts). Therefore, by calculating the integration ratio of these respective peaks, the above molar ratio [T3 body / T2 body] is determined. Specifically, for example, when the silsesquioxane (X) has the formula (1) represented above, R 1When it is a structural unit of 2-(3,4-epoxycyclohexyl)ethyl, the signal of the silicon atom in the structure (T3 form) represented by the above formula (I) appears at -64 to -70 ppm, and the signal of the silicon atom in the structure (T2 form) represented by the above formula (II) appears at -54 to -60 ppm. Therefore, in this case, the molar ratio [T3 form / T2 form] can be obtained by calculating the integral ratio of the signal at -64 to -70 ppm (T3 form) to the signal at -54 to -60 ppm (T2 form).

[0107] For the silsesquioxane (X) 29 The Si-NMR spectrum can be measured, for example, by the following apparatus and conditions.

[0108] Measuring apparatus: Trade name “JNM-ECA500 NMR” (manufactured by JEOL Ltd.).

[0109] Solvent: Deuterochloroform.

[0110] Number of integration times: 1800 times.

[0111] Measuring temperature: 25 °C.

[0112] The fact that the molar ratio [T3 form / T2 form] of the silsesquioxane (X) is 5 or more means that there is a certain amount or more of the T2 form relative to the T3 form in the silsesquioxane (X). Examples of such T2 forms include the structural unit represented by the following formula (4), the structural unit represented by the following formula (5), the structural unit represented by the following formula (6), etc. R in the following formula (4) 1 and R in the following formula (5) 2 are the same as R in the above formula (1) 1 and R in the above formula (2) 2 respectively. R in the following formulas (4) to (6) c is the same as R in formula (II) c and represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0113] [R 1 SiO 2 / 2 (OR c )](4)

[0114] [R 2 SiO 2 / 2 (OR c )](5)

[0115] [HSiO 2 / 2 (OR c )](6)

[0116] The cationically polymerizable sesquioxane (especially sesquioxane (X)) can be a sesquioxane having a cage shape (cage-type sesquioxane). The cage-type sesquioxane includes a complete cage-type sesquioxane and an incomplete cage-type sesquioxane, and among them, the incomplete cage-type sesquioxane is preferred.

[0117] Generally, the complete cage-type sesquioxane is a polyorganosiloxane composed only of T3 units, and there is no T2 unit in the molecule. That is, it is implied that the above molar ratio [T3 unit / T2 unit] is 5 or more, and the sesquioxane having an inherent absorption peak at around 1100 cm -1 as described later has an incomplete cage-type sesquioxane structure.

[0118] Whether the sesquioxane (X) has a cage-type (incomplete cage-type) sesquioxane structure can be confirmed by FT-IR spectrum [Reference: R.H. Raney, M. Itoh, A. Sakakibara and T. Suzuki, Chem. Rev. 95, 1409 (1995)]. Specifically, in the FT-IR spectrum, when there are no inherent absorption peaks at around 1050 cm -1 and around 1150 cm -1 respectively, and there is an inherent absorption peak at around 1100 cm -1 , the sesquioxane (X) is identified as having a cage-type (incomplete cage-type) sesquioxane structure. In contrast, when there are inherent absorption peaks at around 1050 cm -1 and around 1150 cm -1 respectively in the FT-IR spectrum, it is identified as having a ladder-type sesquioxane structure. It should be noted that the FT-IR spectrum of the sesquioxane (X) can be measured, for example, by the following apparatus and conditions.

[0119] Measuring apparatus: Trade name "FT-720" (manufactured by Horiba, Ltd.).

[0120] Measuring method: Transmission method.

[0121] Resolution: 4 cm -1 .

[0122] Measuring wavenumber range: 400 - 4000 cm -1 .

[0123] Integration times: 16 times.

[0124] The proportion (total amount) of the structural unit having a cationic polymerizable functional group (such as the structural unit represented by the above formula (1), the structural unit represented by the above formula (4), etc.) in the cationic polymerizable silsesquioxane relative to the total amount of the siloxane structural units [all siloxane structural units; the total amount of M unit, D unit, T unit and Q unit] (100 mol%) is not particularly limited, and is preferably 50 mol% or more (for example, 50 to 100 mol%), more preferably 55 to 100 mol%, still more preferably 65 to 99.9 mol%, further preferably 80 to 99 mol%, and particularly preferably 90 to 98 mol%. If the above proportion is 50 mol% or more, the curability of the curable composition is improved, or the surface hardness of the coating is significantly increased. It should be noted that the proportion of each siloxane structural unit in the cationic polymerizable silsesquioxane can be calculated, for example, from the composition of the raw materials and NMR spectrum measurement.

[0125] The proportion of the structural unit (T3 body) represented by the above formula (I) in the silsesquioxane (X) relative to the total amount of the siloxane structural units [all siloxane structural units; the total amount of M unit, D unit, T unit and Q unit] (100 mol%) is not particularly limited, and is preferably 50 mol% or more, more preferably 60 to 99 mol%, still more preferably 70 to 98 mol%, further preferably 80 to 95 mol%, and particularly preferably 85 to 92 mol%. It is speculated that by setting the proportion of the structural unit of the T3 body to 50 mol% or more, it is easy to form an incomplete cage shape with an appropriate molecular weight, but there is a tendency that the surface hardness of the hard coating is further increased.

[0126] The proportion (total amount) of the structural unit represented by the above formula (2) and the structural unit represented by the above formula (5) in the silsesquioxane (X) relative to the total amount of the siloxane structural units [all siloxane structural units; the total amount of M unit, D unit, T unit and Q unit] (100 mol%) is not particularly limited, and is preferably 0 to 50 mol%, more preferably 0 to 40 mol%, still more preferably 0 to 30 mol%, and particularly preferably 1 to 15 mol%. By setting the above proportion to 50 mol% or less, the proportion of the structural unit having a cationic polymerizable functional group can be relatively increased, so that the curability of the curable composition is improved, and there is a tendency that the surface hardness of the hard coating becomes higher.

[0127] The ratio (total amount) of the structural unit represented by the above formula (I) and the structural unit represented by the above formula (II) in the silsesquioxane (X) with respect to the total amount of the siloxane structural units [total siloxane structural units; total amount of M unit, D unit, T unit, and Q unit] (100 mol%) (total amount) (especially the total ratio of T3 body and T2 body) is not particularly limited, preferably 60 mol% or more (for example, 60 - 100 mol%), more preferably 70 mol% or more, further preferably 80 mol% or more, and particularly preferably 90 mol% or more. It is speculated that by setting the above ratio to 60 mol% or more, it is easy to form an incomplete cage shape with an appropriate molecular weight, but there is a tendency for the surface hardness of the hard coat to be further improved. Particularly preferably, the ratio (total amount) of the structural unit represented by the above formula (1), the structural unit represented by the above formula (2), the structural unit represented by the above formula (4), and the structural unit represented by the above formula (5) is within the above range.

[0128] The number average molecular weight (Mn) in terms of standard polystyrene obtained by gel permeation chromatography of the silsesquioxane (X) is not particularly limited, preferably 1000 - 3000, more preferably 1000 - 2800, further preferably 1100 - 2600, and particularly preferably 1500 - 2500. By setting the number average molecular weight to 1000 or more, there is a tendency for the surface hardness of the hard coat to be further improved. Or there is a tendency for the heat resistance and abrasion resistance of the hard coat to be improved. On the other hand, by setting the number average molecular weight to 3000 or less, there is a tendency for the compatibility with other components in the curable composition to be improved and the heat resistance of the hard coat to be improved.

[0129] The molecular weight dispersity (Mw / Mn) in terms of standard polystyrene based on gel permeation chromatography of the silsesquioxane (X) is not particularly limited, preferably 1.0 - 3.0, more preferably 1.1 - 2.0, further preferably 1.2 - 1.9, further preferably 1.3 - 1.8, and particularly preferably 1.45 - 1.80. By setting the molecular weight dispersity to 3.0 or less, there is a tendency for the surface hardness of the hard coat to become higher. On the other hand, by setting the molecular weight dispersity to 1.0 or more (especially 1.1 or more), there is a tendency for it to be easily in a liquid state and the operability to be improved.

[0130] It should be noted that the number average molecular weight and molecular weight dispersity of the silsesquioxane (X) can be measured by the following apparatus and conditions.

[0131] Measuring apparatus: Trade name "LC - 20AD" (manufactured by Shimadzu Corporation).

[0132] Chromatographic column: Shodex KF - 801 × 2 pieces, KF - 802, and KF - 803 (manufactured by Showa Denko K.K.).

[0133] Measurement temperature: 40 °C.

[0134] Eluent: THF, sample concentration 0.1 - 0.2 mass%.

[0135] Flow rate: 1 mL / min.

[0136] Detector: UV-VIS detector (trade name "SPD-20A", manufactured by Shimadzu Corporation).

[0137] Molecular weight: in terms of standard polystyrene.

[0138] The cationic polymerizable silsesquioxane can be produced by a known or conventional method for producing silsesquioxane, and is not particularly limited. For example, it can be produced by hydrolyzing and condensing one or more hydrolyzable silane compounds.

[0139] The content ratio of the polyorganosilsesquioxane in the above curable composition is not particularly limited. Relative to the total amount (100 mass%) of the curable compounds, it is preferably more than 50 mass% (for example, more than 50 mass% and 98 mass% or less), more preferably 60 - 96 mass%, further preferably 70 - 95 mass%, and particularly preferably 80 - 93 mass%. If the above content ratio is more than 50 mass%, the surface hardness of the hard coat tends to be further improved. If the above content ratio is 98 mass% or less, other components can be contained in the curable composition, and the effects obtained by containing them tend to be further improved. In addition, a curing catalyst can be contained in the curable composition, and thus there is a tendency that the curing of the curable composition can be carried out more efficiently.

[0140] The above curable composition preferably contains a compound having one or more cationic polymerizable groups and one or more radical polymerizable groups in the molecule (hereinafter sometimes referred to as "compound (A)"). By containing compound (A), the above curable composition can effectively increase the crosslinking density when forming a cured product, easily impart high surface hardness, excellent flexibility and flexural durability to the hard coat, and can prevent the antifouling performance from being easily reduced. It should be noted that only one kind of compound (A) can be used, or two or more kinds can be used.

[0141] Examples of the "cationic polymerizable group" possessed by compound (A) include an epoxy group, an oxetanyl group, a vinyl ether group, a hydroxyl group, etc. From the viewpoint of suppressing the reduction of the surface hardness, flexibility and flexural durability of the hard coat, an epoxy group is preferred. It should be noted that when compound (A) has two or more cationic polymerizable groups, these cationic polymerizable groups can be the same or different from each other.

[0142] Examples of the "radical polymerizable group" possessed by the compound (A) include (meth)acryloyl group, vinyl group, etc. From the viewpoints of the surface hardness and bending durability of the hard coat, the (meth)acryloyl group is preferred. It should be noted that when the compound (A) has two or more radical polymerizable groups, these radical polymerizable groups may be the same or different from each other.

[0143] The number of cationic polymerizable groups possessed by the compound (A) in one molecule is preferably 1 or more, and there is no particular limitation. It is preferably 1 to 5, more preferably 1 to 3, and further preferably 1 or 2. In addition, the number of radical polymerizable groups possessed by the compound (A) in one molecule is preferably 1 or more, and there is no particular limitation. For example, it is preferably 1 to 5, more preferably 1 to 3, and further preferably 1 or 2.

[0144] The functional group equivalent of the cationic polymerizable group of the compound (A) is not particularly limited, preferably 50 to 500, more preferably 80 to 480, and further preferably 120 to 450. If the above functional group equivalent is 50 or more, it is easy to sufficiently improve the bending durability of the hard coat. If the above functional group equivalent is 500 or less, the surface hardness of the hard coat can be made sufficient. It should be noted that the functional group equivalent of the cationic polymerizable group of the compound (A) can be calculated by the following formula.

[0145] [Functional group equivalent of cationic polymerizable group] = [Molecular weight of compound (A)] / [Number of cationic polymerizable groups possessed by compound (A)]

[0146] The functional group equivalent of the radical polymerizable group of the compound (A) is not particularly limited, preferably 50 to 500, more preferably 80 to 480, and further preferably 120 to 450. If the above functional group equivalent is 50 or more, it is easy to sufficiently improve the bending durability of the hard coat. If the above functional group equivalent is 500 or less, the surface hardness of the hard coat can be made sufficient. It should be noted that the functional group equivalent of the radical polymerizable group of the compound (A) can be calculated by the following formula.

[0147] [Functional group equivalent of radical polymerizable group] = [Molecular weight of compound (A)] / [Number of radical polymerizable groups possessed by compound (A)]

[0148] As the compound (A), specifically, for example, the following can be mentioned: 3,4-epoxycyclohexylmethyl (meth)acrylate, glycidyl (meth)acrylate, dipropylene glycol diglycidyl ether di(meth)acrylate (a compound obtained by reacting two epoxy groups of dipropylene glycol diglycidyl ether with (meth)acrylic acid), dipropylene glycol diglycidyl ether semi(meth)acrylate (a compound obtained by reacting one epoxy group of dipropylene glycol diglycidyl ether with (meth)acrylic acid), bisphenol A epoxy di(meth)acrylate (a compound obtained by reacting two epoxy groups of bisphenol A diglycidyl ether with (meth)acrylic acid), bisphenol A epoxy semi(meth)acrylate (a compound obtained by reacting one epoxy group of bisphenol A diglycidyl ether with (meth)acrylic acid or its derivative), bisphenol F epoxy di(meth)acrylate, bisphenol F epoxy semi(meth)acrylate, bisphenol S epoxy di(meth)acrylate, bisphenol S epoxy semi(meth)acrylate, etc., which are compounds having an epoxy group and a (meth)acryloyl group in one molecule; 3-oxetanylmethyl (meth)acrylate, 3-methyl-3-oxetanylmethyl (meth)acrylate, 3-ethyl-3-oxetanylmethyl (meth)acrylate, 3-butyl-3-oxetanylmethyl (meth)acrylate, 3-hexyl-3-oxetanylmethyl (meth)acrylate, etc., which are compounds having an oxetanyl group and a (meth)acryloyl group in one molecule; 2-vinyloxyethyl (meth)acrylate, 3-vinyloxypropyl (meth)acrylate, 1-methyl-2-vinyloxyethyl (meth)acrylate, 2-vinyloxypropyl (meth)acrylate, 4-vinyloxybutyl (meth)acrylate, 1-methyl-3-vinyloxypropyl (meth)acrylate, 1-vinyloxymethylpropyl (meth)acrylate, 2-methyl-3-vinyloxypropyl (meth)acrylate, 1,1-dimethylethyl 2-vinyloxyethyl ether, 3-vinyloxybutyl (meth)acrylate, 1-methyl-2-vinyloxypropyl (meth)acrylate, 2-vinyloxybutyl (meth)acrylate, 4-vinyloxycyclohexyl (meth)acrylate, 6-vinyloxyhexyl (meth)acrylate, 4-vinyloxymethylcyclohexylmethyl (meth)acrylate, 3-vinyloxymethylcyclohexylmethyl (meth)acrylate, 2-vinyloxycyclohexylmethyl (meth)acrylate, p-vinyloxymethylphenyl (meth)acrylate, m-vinyloxymethylphenyl (meth)acrylate, o-vinyloxymethylphenyl (meth)acrylate, 2-(vinyloxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxy)propyl (meth)acrylate, 2-(vinyloxyethoxy)isopropyl (meth)acrylate, 2-(vinyloxyisopropoxy)propyl (meth)acrylate, 2-(vinyloxyisopropoxy)isopropyl (meth)acrylate, 2-(vinyloxyethoxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyisopropoxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyisopropoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxyethoxy)propyl (meth)acrylate, 2-(vinyloxyethoxyisopropoxy)propyl (meth)acrylate, 2-(vinyloxyisopropoxyethoxy)propyl (meth)acrylate, 2-(vinyloxyisopropoxyisopropoxy)propyl (meth)acrylate, 2-(vinyloxyethoxyethoxy)isopropyl (meth)acrylate, 2-(vinyloxyethoxyisopropoxy)isopropyl (meth)acrylate, 2-(vinyloxyisopropoxyethoxy)isopropyl (meth)acrylate, 2-(vinyloxyisopropoxyisopropoxy)isopropyl (meth)acrylate, 2-(vinyloxyethoxyethoxyethoxy)ethyl (meth)acrylate, 2-(vinyloxyethoxyethoxyethoxyethoxy)ethyl (meth)acrylate, 2-(isopropenyloxyethoxy)ethyl (meth)acrylate, 2-(isopropenyloxyethoxyethoxy)ethyl (meth)acrylate, 2-(isopropenyloxyethoxyethoxyethoxy)ethyl (meth)acrylate, 2-(isopropenyloxyethoxyethoxyethoxyethoxy)ethyl (meth)acrylate, polyethylene glycol mono vinyl ether (meth)acrylate, polypropylene glycol mono vinyl ether (meth)acrylate and other compounds having a vinyl ether group and a (meth)acryloyl group in one molecule, etc.,

[0149] From the viewpoints of the bending durability and surface hardness of the hard coat, as the compound (A), a compound having an epoxy group as a cationic polymerizable group and a (meth)acryloyl group as a radical polymerizable group in one molecule is preferred. Specifically, methyl 3,4-epoxycyclohexyl (meth)acrylate, glycidyl (meth)acrylate, dipropylene glycol diglycidyl ether hemis (meth)acrylate, bisphenol A epoxy hemis (meth)acrylate, bisphenol F epoxy hemis (meth)acrylate, bisphenol S epoxy hemis (meth)acrylate, etc. are preferred.

[0150] The compound (A) can be produced by a known method. For example, it can be obtained by reacting a part of the above-mentioned cationic polymerizable groups of a compound having two or more cationic polymerizable groups (such as an epoxy group) in one molecule with a carboxylic acid having a radical polymerizable group (such as acrylic acid, methacrylic acid, etc.) or its derivative. In addition, as the above-mentioned compound (A), for example, commercially available products such as the trade names "LIGHTESTER G", "EPOXYESTER 200PA", "EPOXYESTER 200PA-E5" (manufactured by Kyoeisha Chemical Co., Ltd.), and the trade name "NK OLIGO EA1010N" (manufactured by Shin-Nakamura Chemical Co., Ltd.) can also be used.

[0151] The content ratio of the compound (A) in the above-mentioned curable composition is not particularly limited. Relative to the total amount (100% by mass) of the curable compounds, it is preferably 0.05 to 8% by mass, more preferably 0.1 to 5% by mass, and further preferably 0.2 to 3% by mass. If the above content ratio is within the above range, the sebum adhesion resistance of the surface of the hard coat is more excellent.

[0152] The content (mixing amount) of the compound (A) in the above-mentioned curable composition is not particularly limited. As a solid component, relative to 100 parts by mass of the above-mentioned polyorganosilsesquioxane, it is preferably 1 to 100 parts by mass, more preferably 1.5 to 75 parts by mass, and further preferably 2 to 50 parts by mass. By setting the content of the compound (A) to 1 part by mass or more, the bending property and bending durability of the hard coat tend to be further improved. On the other hand, by setting the content of the compound (A) to 100 parts by mass or less, the surface hardness of the hard coat tends to be maintained.

[0153] In addition, the above-mentioned curable composition preferably contains an aliphatic compound having two or more cationic polymerizable groups in the molecule (hereinafter sometimes referred to as compound (B)). By containing the compound (B), flexibility can be imparted to the hard coat, and bending and bending durability can be easily exhibited. It should be noted that the compound (B) is a compound that does not correspond to the above-mentioned polyorganosilsesquioxane and compound (A). As the compound (B), only one kind can be used, or two or more kinds can be used.

[0154] As the above-mentioned cationic polymerizable group, the same groups as those exemplified in compound (A) can be mentioned. For example, an epoxy group, an oxetanyl group, a vinyl ether group, etc. can be mentioned. From the viewpoint of exhibiting the surface hardness, flexibility, and flexural durability of the above-mentioned hard coat, an epoxy group is preferred, and from the viewpoint of reactivity, a glycidyl group is more preferred. It should be noted that the two or more cationic polymerizable groups possessed by compound (B) may be the same or different respectively.

[0155] The number of cationic polymerizable groups possessed by compound (B) in one molecule is preferably 2 or more, and there is no particular limitation. For example, it is preferably 2 to 5, more preferably 2 to 3, and further preferably 2.

[0156] The functional group equivalent of the cationic polymerizable group of compound (B) is not particularly limited, and is preferably 50 to 500, more preferably 80 to 480, and further preferably 120 to 450. If the above-mentioned functional group equivalent is 50 or more, the flexural durability of the hard coat is likely to be sufficient. If the above-mentioned functional group equivalent is 500 or less, the surface hardness of the hard coat can be made sufficient. It should be noted that the functional group equivalent of the cationic polymerizable group of compound (B) can be calculated by the following formula.

[0157] [Functional group equivalent of cationic polymerizable group] = [Molecular weight of compound (B)] / [Number of thermally polymerizable functional groups possessed by compound (B)]

[0158] The "aliphatic compound" in compound (B) refers to an aliphatic compound that does not have a cyclic structure other than the above-mentioned cationic polymerizable group. As compound (B), for example, glycidyl ethers of dihydric or higher alcohols without a cyclic structure; glycidyl esters of dihydric or higher carboxylic acids [such as adipic acid, sebacic acid, maleic acid, itaconic acid, etc.] can be mentioned. As the above-mentioned dihydric or higher alcohols without a cyclic structure, for example, dihydric alcohols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol; polyhydric alcohols with 3 or more hydroxyl groups such as glycerol, diglycerol, erythritol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol, etc. In addition, the dihydric or higher alcohols can be polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, etc.

[0159] In addition, compound (B) is preferably a compound having cationic polymerizable groups at both ends thereof, and specifically, an aliphatic glycidyl ether type epoxy compound is preferred.

[0160] As the above-mentioned aliphatic glycidyl ether type epoxy compound, for example, there can be mentioned: (poly)alkylene glycol diglycidyl ethers such as ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, triethylene glycol diglycidyl ether, etc., and diol diglycidyl ethers such as 1,6-hexanediol diglycidyl ether. As commercially available products of the aliphatic glycidyl ether type epoxy compound, there can be mentioned: trade names "Epolight40E", "Epolight 100E", "Epolight 200E", "Epolight 400E", "Epolight1600N" (manufactured by Kyoeisha Chemical Co., Ltd.), trade name "YH-300" (manufactured by Nippon Steel Chemical & Material Co., Ltd.), etc.

[0161] The content ratio of the compound (B) in the above-mentioned curable composition is not particularly limited, and is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and further preferably 3 to 10% by mass with respect to the total amount (100% by mass) of the curable compounds. If the above content ratio is within the above range, the flexibility and bending resistance of the hard coat become more appropriate.

[0162] The content of the compound (B) is not particularly limited, and is preferably 1 to 20 parts by mass, more preferably 2 to 15 parts by mass, and further preferably 3 to 10 parts by mass with respect to 100 parts by mass of the above-mentioned polyorganosilsesquioxane. If the above content is within the above range, the flexibility and bending resistance of the hard coat become more appropriate.

[0163] Preferably, the above-mentioned curable composition contains a curing catalyst. The above-mentioned curing catalyst is a compound capable of initiating or promoting the polymerization reaction of curable compounds such as the above-mentioned polyorganosilsesquioxane, compound (A), and compound (B). The above-mentioned curing catalyst can be used alone or in combination of two or more.

[0164] As the above-mentioned curing catalyst, it is selected according to the type of curable functional group possessed by the above-mentioned curable compound, and among them, a cationic polymerization initiator and / or a radical polymerization initiator are preferred. The above-mentioned cationic polymerization initiator is a compound that generates cation species by heat or active energy ray irradiation and initiates the curing reaction of the curable compound.

[0165] As the above-mentioned cationic polymerization initiator, there can be mentioned a photo cationic polymerization initiator (photoacid generator) and a thermal cationic polymerization initiator (thermal acid generator).

[0166] As the above-mentioned photo cationic polymerization initiator, known or commonly used photo cationic polymerization initiators can be used. For example, the following can be cited: sulfonium salts (salts formed by sulfonium ions and anions), iodonium salts (salts formed by iodonium ions and anions), selenonium salts (salts formed by selenonium ions and anions), ammonium salts (salts formed by ammonium ions and anions), phosphonium salts (salts formed by phosphonium ions and anions), salts formed by transition metal complex ions and anions, and the like.

[0167] As the above-mentioned sulfonium salts, for example, the following can be cited: triaryl sulfonium salts such as triphenyl sulfonium salts, tri-p-tolyl sulfonium salts, tri-o-tolyl sulfonium salts, tris(4-methoxyphenyl) sulfonium salts, 1-naphthyldiphenyl sulfonium salts, 2-naphthyldiphenyl sulfonium salts, tris(4-fluorophenyl) sulfonium salts, tri-1-naphthyl sulfonium salts, tri-2-naphthyl sulfonium salts, tris(4-hydroxyphenyl) sulfonium salts, diphenyl[4-(phenylthio)phenyl] sulfonium salts, 4-(p-tolylthio)phenyl di-(p-phenyl) sulfonium salts; diaryl sulfonium salts such as diphenyl benzoylmethyl sulfonium salts, diphenyl 4-nitrobenzoylmethyl sulfonium salts, diphenyl benzyl sulfonium salts, diphenyl methyl sulfonium salts; monoaryl sulfonium salts such as phenyl methyl benzyl sulfonium salts, 4-hydroxyphenyl methyl benzyl sulfonium salts, 4-methoxyphenyl methyl benzyl sulfonium salts; trialkyl sulfonium salts such as dimethyl benzoylmethyl sulfonium salts, benzoylmethyl tetrahydrothiophenium salts, dimethyl benzyl sulfonium salts, and the like.

[0168] As the above-mentioned diphenyl[4-(phenylthio)phenyl] sulfonium salts, for example, the following can be cited: diphenyl[4-(phenylthio)phenyl] sulfonium tetrakis(pentafluorophenyl) borate, diphenyl[4-(phenylthio)phenyl] sulfonium hexafluorophosphate, and the like. In addition, commercially available products such as the product named "CPI-100P" (manufactured by San-Apro Ltd., 50% propylene carbonate solution of diphenyl[4-(phenylthio)phenyl] sulfonium hexafluorophosphate) can also be used.

[0169] As the above-mentioned iodonium salts, for example, the following can be cited: the product named "RHODORSIL PHOTOINITIATOR 2074" (manufactured by Rhodia Japan Ltd., tetrakis(pentafluorophenyl) borate = [(1-methylethyl)phenyl](methylphenyl) iodonium), the product named "WPI-124" (manufactured by Wako Pure Chemical Industries, Ltd.), diphenyl iodonium salts, di-p-tolyl iodonium salts, bis(4-dodecylphenyl) iodonium salts, bis(4-methoxyphenyl) iodonium salts, and the like.

[0170] As the above-mentioned selenonium salts, for example, the following can be cited: triaryl selenonium salts such as triphenyl selenonium salts, tri-p-tolyl selenonium salts, tri-o-tolyl selenonium salts, tris(4-methoxyphenyl) selenonium salts, 1-naphthyldiphenyl selenonium salts; diaryl selenonium salts such as diphenyl benzoylmethyl selenonium salts, diphenyl benzyl selenonium salts, diphenyl methyl selenonium salts; monoaryl selenonium salts such as phenyl methyl benzyl selenonium salts; trialkyl selenonium salts such as dimethyl benzoylmethyl selenide salts, and the like.

[0171] As the above-mentioned ammonium salts, examples thereof include: tetraalkylammonium salts such as tetramethylammonium salt, ethyltrimethylammonium salt, diethyldimethylammonium salt, triethylmethylammonium salt, tetraethylammonium salt, trimethyl-n-propylammonium salt, trimethyl-n-butylammonium salt; pyrrolonium salts such as N,N-dimethylpyrrolonium salt, N-ethyl-N-methylpyrrolonium salt; imidazolinium salts such as N,N'-dimethylimidazolinium salt, N,N'-diethylimidazolinium salt; tetrahydropyrimidinium salts such as N,N'-dimethyltetrahydropyrimidinium salt, N,N'-diethyltetrahydropyrimidinium salt; morpholinium salts such as N,N-dimethylmorpholinium salt, N,N-diethylmorpholinium salt; piperidinium salts such as N,N-dimethylpiperidinium salt, N,N-diethylpiperidinium salt; pyridinium salts such as N-methylpyridinium salt, N-ethylpyridinium salt; imidazolium salts such as N,N'-dimethylimidazolium salt; quinolinium salts such as N-methylquinolinium salt; isoquinolinium salts such as N-methylisoquinolinium salt; thiazolium salts such as benzylbenzothiazolium salt; acridinium salts such as benzylacridinium salt, etc.

[0172] As the above-mentioned phosphonium salts, examples thereof include: tetraarylphosphonium salts such as tetraphenylphosphonium salt, tetrakis(p-tolyl)phosphonium salt, tetrakis(2-methoxyphenyl)phosphonium salt; triarylphosphonium salts such as triphenylbenzylphosphonium salt; tetraalkylphosphonium salts such as triethylbenzylphosphonium salt, tributylbenzylphosphonium salt, tetraethylphosphonium salt, tetrabutylphosphonium salt, triethylbenzoylmethylphosphonium salt, etc.

[0173] As the salts of the above-mentioned transition metal complex ions, examples thereof include: salts of chromium complex cations such as (η 5 -cyclopentadienyl)(η 6 -toluene)Cr + , (η 5 -cyclopentadienyl)(η 6 -xylene)Cr + ; salts of iron complex cations such as (η 5 -cyclopentadienyl)(η 6 -toluene)Fe + , (η 5 -cyclopentadienyl)(η 6 -xylene)Fe + , etc.

[0174] As the anions constituting the above-mentioned salts, examples thereof include PF6 - , BF4 - , (C6F5)4B - , (C6F5)4Ga -, sulfonate anions (trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, methanesulfonate anion, benzenesulfonate anion, p-toluenesulfonate anion, etc.), perhalate anions, halogenated sulfonate anions, sulfate anions, carbonate anions, aluminate anions, carboxylate anions, arylborate anions, thiocyanate anions, nitrate anions, etc.

[0175] Examples of the above-mentioned thermal cationic polymerization initiators include arylsulfonium salts, aryl iodonium salts, allene-ion complexes, quaternary ammonium salts, aluminum chelates, boron trifluoride amine complexes, etc. In addition, examples of the anions constituting the above salts include the same anions as those in the photo cationic polymerization initiators.

[0176] Examples of the above-mentioned arylsulfonium salts include pentafluorophenyl borate, hexafluorophosphate, etc. In the curable composition of the present disclosure, for example, commercially available products such as "SP-66", "SP-77" (manufactured by ADEKA Corporation); "San-Aid SI-150L", "San-Aid SI-110", "San-Aid SI-360", "San-Aid SI-300", "San-Aid SI-B4", "San-Aid SI-B5", "San-Aid SI-B3", "San-Aid SI-B3A", "San-Aid SI-B7", "San-Aid SI-B2A" (manufactured by Sanshin Chemical Industry Co., Ltd.) can be used. Examples of the above-mentioned aluminum chelates include ethyl acetoacetate aluminum diisopropylate, tris(ethylacetoacetato)aluminum, etc. In addition, examples of the above-mentioned boron trifluoride amine complexes include boron trifluoride monoethylamine complex, boron trifluoride imidazole complex, boron trifluoride piperidine complex, etc.

[0177] The above-mentioned radical polymerization initiator is a compound that generates radicals by heat or irradiation with active energy rays and initiates the curing reaction of the curable compound.

[0178] Examples of the above-mentioned radical polymerization initiators include photo radical polymerization initiators and thermal radical polymerization initiators. Examples of the above-mentioned photo radical polymerization initiators include alkylbenzophenone-based photo radical polymerization initiators, acylphosphine oxide-based photo radical polymerization initiators, oxime ester-based photo radical polymerization initiators, α-hydroxyketone-based photo radical polymerization initiators, etc.

[0179] Examples of the above-mentioned alkyl phenyl ketone-based photo radical polymerization initiators include: 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-[4-(4-morpholinyl)phenyl]-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, benzophenone, methylbenzophenone, o-benzoylbenzoic acid, benzoyl ethyl ether, 2,2-diethoxyacetophenone, 2,4-diethylthioxanthone, diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl-(2,4,6-trimethylbenzoyl)phenylphosphonate, 4,4'-bis(diethylamino)benzophenone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, oligomers of 2-hydroxy-1-(4-isopropenylphenyl)-2-methylpropan-1-one, etc.

[0180] Examples of the above-mentioned acylphosphine oxide-based photo radical polymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, etc.

[0181] Examples of the above-mentioned oxime ester-based photo radical polymerization initiators include 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyloxy), 1-[6-(2-methylbenzoyl)-9-ethyl-9H-carbazol-3-yl]ethanone O-acetyl oxime, etc.

[0182] Examples of the above-mentioned α-hydroxy ketone-based photo radical polymerization initiators include: benzoin, benzoin methyl ether, benzoin butyl ether, 1-hydroxycyclohexyl phenyl ketone, 1-phenyl-2-hydroxy-2-methylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone, 1-hydroxycyclohexyl phenyl ketone, etc.

[0183] The content (blending amount) of the above-mentioned curing catalyst in the above-mentioned curable composition is not particularly limited, and is preferably 0.01 to 10 parts by mass, more preferably 0.03 to 5 parts by mass, and still more preferably 0.05 to 3 parts by mass, based on 100 parts by mass of the total amount of the curable compound. When the content of the curing catalyst is 0.01 part by mass or more, the curing reaction can be carried out efficiently and sufficiently, and there is a tendency for the surface hardness of the hard coat to be further improved. On the other hand, when the content of the curing catalyst is 10 parts by mass or less, the storage stability of the curable composition is improved, and the coloring of the cured product is suppressed.

[0184] The content (mixing amount) of the cationic polymerization initiator in the above curable composition is not particularly limited, and is preferably 0.005 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, still more preferably 0.015 to 3 parts by mass, and particularly preferably 0.02 to 2 parts by mass, based on 100 parts by mass of the total amount of the curable compound. If the above content is 0.005 parts by mass or more, the curing reaction can be carried out efficiently and sufficiently, and there is a tendency for the surface hardness of the cured product to be further improved. If the above content is 10 parts by mass or less, there is a tendency for the storage stability of the curable composition to be improved and the coloring of the cured product to be suppressed.

[0185] The content (mixing amount) of the radical polymerization initiator in the above curable composition is not particularly limited, and is preferably 0.01 to 5 parts by mass, more preferably 0.03 to 3 parts by mass, still more preferably 0.05 to 2 parts by mass, based on 100 parts by mass of the total amount of the curable compound. If the above content is 0.01 parts by mass or more, the curing reaction can be carried out efficiently and sufficiently, and there is a tendency for the surface hardness of the cured product to be further improved. If the above content is 5 parts by mass or less, there is a tendency for the storage stability of the curable composition to be improved and the coloring of the cured product to be suppressed.

[0186] Preferably, the above curable composition contains a radical-curable polyorganosiloxane as a leveling agent. By using the above radical-curable polyorganosiloxane, the smoothness of the hard coat surface can be improved, and flexibility and flexural durability can be exhibited. In addition, preferably, the above radical-curable polyorganosiloxane is not equivalent to PFAS. In this case, the above effects can be exhibited without being equivalent to PFAS. The above radical-curable polyorganosiloxane may be used alone or in combination of two or more.

[0187] The above radical-curable polyorganosiloxane has a radical-polymerizable functional group in the molecule. Examples of the above radical-polymerizable functional group include a photo-radical-polymerizable functional group.

[0188] Examples of the above photo-radical-polymerizable functional group include (meth)acryloyl, (meth)acrylamide, vinyl, vinylthio group, etc. Among them, (meth)acryloyl is preferred.

[0189] As the polyorganosiloxane in the above radical-curable polyorganosiloxane, linear polyorganosiloxane is preferred from the viewpoint of further exerting the effect as a leveling agent.

[0190] The content of the above free-radical curable polyorganosiloxane is not particularly limited, and is preferably 0.01 to 5 parts by mass, more preferably 0.03 to 3 parts by mass, and still more preferably 0.05 to 2 parts by mass with respect to 100 parts by mass of the above polyorganosilsesquioxane.

[0191] Preferably, the above curable composition contains an antioxidant. By including an antioxidant in the above curable composition, there is a tendency for the storage stability of the hard coat to be further improved. As the above antioxidant, only one kind may be used, or two or more kinds may be used.

[0192] As the antioxidant, known or conventional antioxidants can be used, and there is no particular limitation. For example, phenolic antioxidants, hindered amine antioxidants, phosphorus antioxidants, sulfur antioxidants, etc. can be cited.

[0193] As the above phenolic antioxidant, for example, monophenols such as 2,6-di-tert-butyl-p-cresol, butylated hydroxyanisole, 2,6-di-tert-butyl-p-ethylphenol, stearyl-β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate, etc.; bisphenols such as 2,2'-methylenebis(4-methyl-6-tert-butylphenol), 2,2'-methylenebis(4-ethyl-6-tert-butylphenol), 4,4'-thiobis(3-methyl-6-tert-butylphenol), 4,4'-butylidenebis(3-methyl-6-tert-butylphenol), 3,9-bis[1,1-dimethyl-2-{β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionyloxy}ethyl] 2,4,8,10-tetraoxaspiro[5.5]undecane, etc.; polymeric phenols such as 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tetra[methylene-3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate]methane, bis[3,3'-bis-(4'-hydroxy-3'-tert-butylphenyl)butyric acid] ethylene glycol ester, 1,3,5-tris(3',5'-di-tert-butyl-4'-hydroxybenzyl)-s-triazine-2,4,6-(1H,3H,5H)trione, tocopherol, etc. can be cited.

[0194] As the above hindered amine antioxidant, for example, bis(1,2,2,6,6-pentamethyl-4-piperidyl) [[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl] malonate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl-1,2,2,6,6-pentamethyl-4-piperidyl sebacate, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, etc. can be cited.

[0195] Examples of the above-mentioned phosphorus-based antioxidants include: phosphite esters such as triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris(nonylphenyl) phosphite, diisodecyl pentaerythritol diphosphite, tris(2,4-di-tert-butylphenyl) phosphite, cyclopentanetetraylbis(octadecyl) phosphite, cyclopentanetetraylbis(2,4-di-tert-butylphenyl) phosphite, cyclopentanetetraylbis(2,4-di-tert-butyl-4-methylphenyl) phosphite, bis[2-tert-butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl] hydrogen phosphite; oxaphosphaphenanthrene oxides such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 10-(3,5-di-tert-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, etc.

[0196] Examples of the above-mentioned sulfur-based antioxidants include: dodecyl mercaptan, dilauryl 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3'-thiodipropionate, etc.

[0197] When the above-mentioned curable composition contains an antioxidant, the content of the antioxidant is not particularly limited. Relative to the total amount (100 parts by mass) of the curable compound, it is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 1 part by mass. If the content of the antioxidant is 0.05 part by mass or more, sufficient stability can be achieved. In addition, if the content of the antioxidant is 5 parts by mass or less, coloring of the hard coat can be suppressed.

[0198] When the above-mentioned curable composition contains an antioxidant, the content of the antioxidant is not particularly limited. Relative to 100 parts by mass of the polyorganosilsesquioxane, it is preferably 0.05 to 5 parts by mass, more preferably 0.1 to 3 parts by mass. If the content of the antioxidant is 0.05 part by mass or more, sufficient stability can be achieved. In addition, if the content of the antioxidant is 5 parts by mass or less, coloring of the hard coat can be suppressed.

[0199] The above-mentioned curable composition may further contain a solvent. As the solvent, there is no particular limitation as long as it can dissolve the above-mentioned polyorganosilsesquioxane and additives used as required and does not hinder the polymerization. The above-mentioned solvent may be used alone or in combination of two or more.

[0200] Preferably, the above solvent is a solvent that can impart fluidity suitable for coating on a hard coat and can be easily removed by heating at a temperature capable of suppressing polymerization. A solvent having a boiling point (under one atmosphere) of 170°C or lower is preferably used (for example, aromatic solvents such as toluene, xylene, and mesitylene, esters such as butyl acetate, ketones such as methyl isobutyl ketone and cyclohexanone, ethers such as propylene glycol monomethyl ether and propylene glycol monomethyl ether acetate, etc.).

[0201] From the aspect of excellent coatability, preferably, the above solvent is used in the range where the concentration of the non-volatile components contained in the curable composition is, for example, preferably 5 to 100% by mass, more preferably 10 to 80% by mass, and particularly preferably 20 to 70% by mass. However, the addition amount should be selected as the optimal addition amount to adjust the viscosity to achieve an appropriate film thickness, and is not limited to the above range. That is, if the amount of the solvent used is excessive, the viscosity of the curable composition decreases, and there is a tendency that it is difficult to form a coating film with an appropriate film thickness. On the other hand, if the amount of the solvent used is too small, the viscosity of the curable composition becomes too high, and there is a tendency that it is difficult to coat the substrate uniformly.

[0202] The above curable composition may further contain the following conventional additives as other components: precipitated silica, wet silica, fumed silica, calcined silica, titanium oxide, alumina, glass, quartz, aluminosilicate, iron oxide, zinc oxide, calcium carbonate, carbon black, silicon carbide, silicon nitride, boron nitride and other inorganic fillers, and inorganic fillers obtained by treating these fillers with organosilicon compounds such as organohalosilanes, organoalkoxysilanes, and organosilazanes; organic resin fine powders such as silicone resins, epoxy resins, and fluororesins; fillers such as conductive metal powders of silver, copper, etc., curing aids, stabilizers (light stabilizers, heat stabilizers, heavy metal passivators, etc.), ultraviolet absorbers (triazine-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, oxybenzophenone-based ultraviolet absorbers, salicylate-based ultraviolet absorbers, cyanoacrylate-based ultraviolet absorbers), flame retardants (phosphorus-based flame retardants, halogen-based flame retardants, inorganic-based flame retardants, etc.), flame retardant aids, reinforcing materials (other fillers, etc.), nucleating agents, coupling agents (silane coupling agents, etc.), lubricants, waxes, plasticizers, mold release agents, impact resistance improvers, hue improvers, clarifying agents, rheology modifiers (flowability improvers, etc.), processability improvers, colorants (dyes, pigments, etc.), antistatic agents, dispersants, surface modifiers (slip agents, etc.), matting agents, defoaming agents, foam suppressants, degassing agents, antibacterial agents, preservatives, viscosity modifiers, tackifiers, photosensitizers, foaming agents, etc. The above other components may be used singly or in combination of two or more. The content of the above other components is not particularly limited, and is preferably 100 parts by mass or less, more preferably 30 parts by mass or less (for example, 0.01 to 30 parts by mass), and still more preferably 10 parts by mass or less (for example, 0.1 to 10 parts by mass) relative to 100 parts by mass of the total amount of the curable compound.

[0203] In addition, the above curable composition does not contain a compound equivalent to PFAS. With the above configuration, without using PFAS, it can become a product compliant with PFAS restrictions.

[0204] The above curable composition is not particularly limited and can be prepared by stirring / mixing the above components at room temperature or while heating as needed. It should be noted that the above curable composition can be used in the form of a one-component system composition in which the components are pre-mixed and maintained in that state, or for example, it can also be used in the form of a multi-component system (for example, a two-component system) composition in which two or more components stored separately are mixed at a specified ratio before use.

[0205] The above-mentioned curable composition is not particularly limited, and is preferably a liquid at normal temperature (about 25°C). More specifically, for the above-mentioned curable composition, the viscosity of the liquid diluted to 20% with a solvent [in particular, a curable composition solution with a proportion of 20% by mass of methyl isobutyl ketone] at 25°C is preferably 300 to 20,000 mPa·s, more preferably 500 to 10,000 mPa·s, and further preferably 1,000 to 8,000 mPa·s. By setting the above viscosity to 300 mPa·s or more, there is a tendency for the cured product (coating film) to be further improved. On the other hand, by setting the above viscosity to 20,000 mPa·s or less, the preparation and treatment of the curable composition become easy, and in addition, there is a tendency for air bubbles not to remain in the cured product (coating film). It should be noted that the viscosity of the above-mentioned curable composition is measured using a viscometer (trade name "MCR301", manufactured by Anton Paar) under the conditions of a swing angle of 5%, a frequency of 0.1 to 100 (1 / s), and a temperature of 25°C.

[0206] As a method for manufacturing the above-mentioned hard coat, it can be manufactured according to a publicly known or conventional method for manufacturing a hard coat, and the manufacturing method is not particularly limited. For example, it can be manufactured by coating the above-mentioned curable composition on at least one surface of the above-mentioned substrate, and removing the solvent by drying as needed, and then curing the above-mentioned curable composition (curable composition layer). The coating method of the curable composition and the conditions during curing are not particularly limited, and can be appropriately selected from the following conditions, for example.

[0207] As a method for coating and curing the above-mentioned hard coat, a usual coating method can be used. For example, known methods such as dipping method, roll coating, gravure coating, reverse coating, air knife coating, comma coating, die coating, screen printing method, spraying, offset gravure printing method, and organic vapor deposition method can be used. As a curing method, for example, light irradiation using a mercury lamp, xenon lamp, carbon arc lamp, metal halide lamp, sunlight, electron beam source, laser light source, LED light source, etc. can be cited. It should be noted that when ultraviolet rays are irradiated during the curing of the above-mentioned hard coat, for example, the cumulative irradiation amount is preferably about 1 to 5000 mJ / cm 2 or so.

[0208] As specific curing conditions, there is no particular limitation. For example, the above-mentioned curable composition can first be subjected to a heat treatment (pre-baking) preferably at 60°C or higher, more preferably at 120°C or higher, and further preferably at 150°C or higher for preferably 10 seconds or more, more preferably 30 seconds or more, and further preferably 60 seconds or more. Then, ultraviolet rays are irradiated (irradiation conditions (irradiation amount): preferably 300 mJ / cm 2 or more; irradiation intensity: 100 mW / cm 2Thereafter, finally, heat treatment (aging) is preferably performed at 120°C or higher for 0.5 hours or longer to cure it. However, the curing conditions are not limited to this range, and the pre-baking temperature, time, aging temperature, and time can be appropriately selected according to the solvent used. In addition, the ultraviolet irradiation conditions can also be appropriately selected according to the curing agent used.

[0209] As described above, the above curable composition can form a hard coat having high surface hardness and toughness through coating and curing. The laminate including the hard coat thus produced is excellent in bendability and bend durability, and can improve the surface hardness of the hard coat.

[0210] In order to further improve the recoatability of the above hard coat, surface treatments such as corona discharge treatment, plasma discharge treatment, ozone exposure treatment, and excimer treatment for surface modification by corona discharge irradiation can be performed on the surface of the above hard coat. Among them, corona discharge treatment is more preferable in terms of being able to easily improve the recoatability.

[0211] Corona discharge treatment is a treatment for processing the surface of a hard coat by generating an uneven electric field around a sharp electrode (needle electrode) to generate continuous discharge. Plasma discharge treatment is a treatment for processing the surface of a hard coat by discharging in the atmosphere to generate activated positive and negative charged particles. Ozone exposure treatment is, for example, a treatment for processing the surface of a hard coat by generating ozone through ultraviolet irradiation using a low-pressure mercury lamp or the like in the presence of oxygen. Excimer treatment is a treatment for processing the surface of a hard coat by ultraviolet irradiation or laser irradiation using an excimer lamp in a vacuum state.

[0212] The haze of the above hard coat is preferably 1% or less, more preferably 0.7% or less, and further preferably 0.5% or less. It should be noted that the lower limit of the haze is, for example, 0.1%. By setting the haze to 1% or less, there is a tendency to be suitable for applications requiring high transparency.

[0213] The thickness of the above hard coat is preferably 5 to 100 μm, more preferably 10 to 70 μm. By the thickness of the hard coat being 5 μm or more, sufficient surface hardness can be exhibited. In addition, by the thickness of the hard coat being 100 μm or less, bendability is easily exhibited. In addition, when the above hard coat is formed on both sides of the above substrate, the thickness of at least one hard coat is preferably 5 μm or more, more preferably 10 μm or more. In addition, from the viewpoint of exhibiting bendability, the thicknesses of the two hard coats are each preferably 60 μm or less, more preferably 50 μm or less.

[0214] [Image display device]

[0215] As an embodiment of the present disclosure, an image display device having the above-described laminate can be cited. In the image display device, the above-described laminate is arranged, for example, such that the above-described hard coat forms the surface on the visible side. The above-described image display device is not particularly limited, and examples thereof include display devices such as an organic electroluminescence display device, an inorganic electroluminescence display device, and a liquid crystal display device. Since the surface of the above-described hard coat has sufficient surface hardness, the surface is not easily damaged and has excellent touch properties. In addition, since the above-described image display device has excellent flexibility and bending durability, it can also be used as a foldable display that can be wound or the like. Moreover, since it has sufficient surface hardness, flexibility, and bending durability, it can also be preferably used as a foldable device including the above-described image display device.

[0216] Each aspect disclosed in this specification can also be combined with any other feature disclosed in this specification. In addition, each configuration and the combination of each configuration in each embodiment are examples, and additional, omission, and other changes of the configuration can be appropriately made without departing from the gist of the present disclosure. The present disclosure is not limited by the embodiments but is limited only by the claims.

[0217] [Examples]

[0218] Hereinafter, an embodiment of the present disclosure will be described in more detail based on examples.

[0219] Production Example 1

[0220] (Production of polyorganosilsesquioxane)

[0221] Into a 1000 ml flask (reaction vessel) equipped with a thermometer, a stirring device, a reflux condenser, and a nitrogen inlet tube, 277.2 mmol (68.30 g) of 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3.0 mmol (0.56 g) of phenyltrimethoxysilane, and 275.4 g of acetone were charged under a nitrogen stream, and the temperature was raised to 50°C. To the mixture thus obtained, 7.74 g of a 5% aqueous potassium carbonate solution (2.8 mmol as potassium carbonate) was added over 5 minutes, and then 2800.0 mmol (50.40 g) of water was added over 20 minutes. It should be noted that no significant temperature rise occurred during the addition. Thereafter, the temperature was maintained at 50°C, and a polycondensation reaction was carried out for 5 hours under a nitrogen stream.

[0222] Thereafter, while cooling the reaction solution, 137.70 g of methyl isobutyl ketone and 100.60 g of 5% brine were added. The solution was transferred to a 1-L separatory funnel, and 137.70 g of methyl isobutyl ketone was added again for washing with water. After liquid separation, the aqueous layer was drawn out and washed with water until the lower layer liquid became neutral. After separating the upper layer liquid, the solvent was distilled off from the upper layer liquid under the conditions of 1 mmHg and 50 °C to obtain 75.18 g of a colorless, transparent, and liquid product containing 23% by mass of methyl isobutyl ketone (epoxy group-containing low-molecular-weight polyorganosilsesquioxane: the silsesquioxane of Production Example 1).

[0223] It should be noted that the product was analyzed, and as a result, the number average molecular weight was 2235, and the molecular weight dispersity was 1.54. The ratio of T2 body to T3 body [T3 body / T2 body] calculated from the 29 Si-NMR spectrum of the above product was 11.9. The obtained epoxy group-containing low-molecular-weight polyorganosilsesquioxane was confirmed by 1 H-NMR, 29 Si-NMR.

[0224] It should be noted that the molecular weight of the product was measured using a pump: Shimadzu LC-20AD, a detector: ShodexRI-504, a chromatographic column: Shodex GPC KF-602, KF-603, a guard column: Shodex GPC KF-G, a solvent: THF, and measurement conditions: 40 °C. In addition, the ratio of T2 body to T3 body [T3 body / T2 body] in the product was measured by 29 Si-NMR spectrum measurement using JEOLECA500 (500 MHz).

[0225] (Preparation of Hard Coating Agent)

[0226] In the above silsesquioxane, each material was mixed so as to achieve the composition ratios shown in Table 1 to prepare hard coating agents for Examples and Comparative Examples. It should be noted that the content ratios shown in the table are the mixing ratios of the respective components. For the silsesquioxane of Production Example 1 (active ingredient 77% by mass) and RS-57 (active ingredient 20% by mass), they are values for solutions, and for the other components, they are values for active ingredients.

[0227] [Table 1]

[0228] Table 1

[0229]

[0230] Regarding each component used in Table 1, details are described below.

[0231] 200PA-E5: Trade name "EPOXYESTER 200PA-E5", manufactured by Kyoeisha Chemical Co., Ltd. (a compound having one or more cationic polymerizable groups and one or more free radical polymerizable groups in the molecule).

[0232] Epolight 1600N: Trade name "Epolight 1600N", manufactured by Kyoeisha Chemical Co., Ltd.

[0233] (An aliphatic compound having two or more cationic polymerizable groups in the molecule).

[0234] Omnirad127: Trade name "Omnirad127", manufactured by IGM Resins B.V. (a free radical polymerization initiator).

[0235] Salt of triarylsulfonium and tetrakis(pentafluorophenyl)gallium: A photo cationic polymerization initiator.

[0236] ADEKA STAB AO-02: Trade name "ADEKA STAB AO-02", manufactured by ADEKA Corporation (an antioxidant).

[0237] KY1203: Trade name "KY1203", containing a compound equivalent to PFAS, manufactured by Shin-Etsu Chemical Co., Ltd. (a leveling agent).

[0238] RS-57: Trade name "RS-57", a silicone resin without a compound equivalent to PFAS, manufactured by DIC Corporation (a leveling agent).

[0239] MIBK: Methyl isobutyl ketone (a solvent).

[0240] MEK: Methyl ethyl ketone (a solvent).

[0241] Examples 1 and 2

[0242] Using a wire bar #12 and #22 respectively, the hard coat agents of the above examples were applied to a PET substrate (trade name "TA069", manufactured by Toyobo Co., Ltd.) so that the cured thickness became 10 μm and 20 μm, and then placed in an oven at 80 °C for 1 minute and in an oven at 120 °C for 2 minutes. Then, using a high-pressure mercury lamp, ultraviolet rays were irradiated at an illuminance of 300 mJ / cm 2 to form a hard coat. Then, it was placed in an oven at 120 °C for 60 minutes to produce the laminates of Examples 1 to 2.

[0243] Comparative Examples 1 and 2

[0244] Using winding rods #12 and #22 respectively, the hard coat agent of the above comparative example was applied to a PET substrate (trade name "TA069", manufactured by Toyobo Co., Ltd.) such that the cured thickness became 10 μm and 20 μm. Except for this, the laminates of Comparative Examples 1 and 2 were produced in the same manner as the laminates of Examples 1 and 2.

[0245] [Evaluation]

[0246] The following evaluations were performed on the laminates produced in the examples and comparative examples, and the results are shown in Table 2.

[0247] (1) Haze

[0248] For the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, the haze value (%) was measured using a haze meter (trade name "NDH-5000W", manufactured by Nippon Denshoku Industries Co., Ltd.). This measurement was carried out in accordance with JIS K7136.

[0249] (2) Total light transmittance

[0250] For the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, the total light transmittance (%) was measured using a total light transmittance meter (trade name "NDH-5000W", manufactured by Nippon Denshoku Industries Co., Ltd.). This measurement was carried out in accordance with JIS K7105.

[0251] (3) Pencil hardness

[0252] For the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, the pencil hardness of the hard coat surface was evaluated in accordance with JIS K 5600-5-4 (750 g load).

[0253] (4) Abrasion resistance

[0254] For the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, #0000 steel wool was reciprocated 1000 times with a load of 750 g / cm 2 against the surface of the hard coat, and the presence or absence of damage on the hard coat surface was confirmed.

[0255] (5) Flexibility

[0256] For the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, using a cylindrical mandrel bending tester (trade name "Bending Tester (Cylindrical Mandrel Method)", manufactured by TP Giken Co., Ltd.), the flexibility was measured for both cases where the hard coat was on the inside and the outside by the cylindrical mandrel method in accordance with JISK5600-5-1 (1999).

[0257] (6) Continuous bending durability

[0258] For the laminates of Example 1, Example 2, Comparative Example 1, and Comparative Example 2, the continuous bending durability was measured using a flat body unloaded U-shaped stretching and bending tester (trade name “Z-044”, manufactured by Yuasa System Equipment Co., Ltd.). In the measurement, the surface of the hard coat was set as the convex side, the laminate was bent 180° such that the bending radius became 4.0 mm, the laminate was stretched again, and this action was defined as one cycle. The above action was performed 10,000 times at a speed of 30 to 60 cycles per minute, and the presence or absence of cracks in the hard coat and the PET substrate was confirmed.

[0259] [Table 2]

[0260] Table 2

[0261]

[0262] It was confirmed that the laminate of the example exhibited the same hardness and bendability as the laminate of the comparative example using a compound equivalent to PFAS, and exhibited sufficient abrasion resistance and bendability without using a fluorine compound.

[0263] Hereinafter, modifications of the invention of the present disclosure will be described.

[0264] [Supplementary Note 1]

[0265] A laminate having a substrate and a hard coat laminated on at least one surface of the substrate, wherein the hard coat does not contain a compound equivalent to PFAS, and in a cylindrical mandrel test in which the laminate is bent such that the surface of the hard coat of the laminate becomes convex, the minimum bendable radius of the laminate is 5 mm or less.

[0266] [Supplementary Note 2]

[0267] The laminate according to Supplementary Note 1, wherein the number of actions until cracks occur in the hard coat is 10,000 or more in the following bending durability test.

[0268] Bending durability test:

[0269] Starting from the state after stretching the laminate, the laminate is bent 180° such that the bending radius becomes 4.0 mm in the direction in which the surface of the hard coat becomes convex, the laminate is stretched again, and this action is defined as one cycle. The above action is performed at a speed of 30 to 60 cycles per minute.

[0270] [Supplementary Note 3]

[0271] The laminate according to Supplementary Note 1 or 2, wherein in a steel wool resistance test in which a load of 750 g / cm 2 is applied to the surface of the hard coat with #0000 steel wool and the surface of the hard coat is reciprocally rubbed 1,000 times, no damage is visually observed.

[0272] [Supplementary Note 4]

[0273] The laminate according to any one of Supplementary Notes 1 to 3, wherein the haze of the hard coat is 1.0% or less.

[0274] [Supplementary Note 5]

[0275] The laminate according to any one of Supplementary Notes 1 to 4, wherein the haze of the laminate is 7% or less.

[0276] [Supplementary Note 6]

[0277] The laminate according to any one of Supplementary Notes 1 to 5, wherein the hard coat is a cured product of a curable composition containing one or more curable compounds, and the curable compound contains polyorganosilsesquioxane.

[0278] [Supplementary Note 7]

[0279] The laminate according to Supplementary Note 6, wherein the curable composition contains a compound having one or more cationic polymerizable groups and one or more radical polymerizable groups in the molecule.

[0280] [Supplementary Note 8]

[0281] The laminate according to Supplementary Note 6 or 7, wherein the curable composition further contains a curing catalyst.

[0282] [Supplementary Note 9]

[0283] The laminate according to Supplementary Note 8, wherein the curing catalyst contains a cationic polymerization initiator.

[0284] [Supplementary Note 10]

[0285] The laminate according to Supplementary Note 8 or 9, wherein the curing catalyst contains a radical polymerization initiator.

[0286] [Supplementary Note 11]

[0287] The laminate according to any one of Supplementary Notes 6 to 10, wherein the curable composition further contains a radically curable polyorganosiloxane.

[0288] [Supplementary Note 12]

[0289] The laminate according to any one of Supplementary Notes 6 to 11, wherein the curable composition further contains an aliphatic compound having two or more cationic polymerizable groups in the molecule.

[0290] [Supplementary Note 13]

[0291] The laminate according to any one of Appendices 1 to 12, wherein the substrate is a transparent substrate.

[0292] [Appendix 14]

[0293] The laminate according to any one of Appendices 1 to 13, wherein the laminate has a surface protective film on at least one surface.

[0294] [Appendix 15]

[0295] The laminate according to any one of Appendices 1 to 14, wherein the laminate has the hard coat on one surface of the substrate and an adhesive layer on the other surface.

[0296] [Appendix 16]

[0297] An image display device including the laminate according to any one of Appendices 1 to 15.

[0298] [Appendix 17]

[0299] The image display device according to Appendix 16, wherein the image display device is a foldable display.

[0300] [Appendix 18]

[0301] The image display device according to Appendix 16 or 17, wherein the image display device is an organic electroluminescent display device.

[0302] [Appendix 19]

[0303] A foldable device including the image display device according to any one of Appendices 16 to 18.

Claims

1. A laminate having a substrate and a hard coat laminated on at least one surface of the substrate, wherein the hard coat does not contain a compound equivalent to PFAS, and in a cylindrical mandrel test in which the surface of the hard coat of the laminate is convex, the minimum bendable radius of the laminate is 5 mm or less.

2. The laminate according to claim 1, wherein in the following bend durability test, the number of operations until cracks occur in the hard coat is 10,000 times or more, Bend durability test: Starting from the state after stretching the laminate, bend 180° in such a way that the bending radius becomes 4.0 mm in the direction in which the surface of the hard coat is convex, stretch the laminate again, and set the above operation as one time, and perform the operation at a speed of 30 to 60 times per minute.

3. The laminate according to claim 1 or 2, wherein The hard coating is subjected to a steel wool test in which a load of 750 g / cm is applied with #0000 steel wool on one side and the surface of the hard coating is reciprocally rubbed 1000 times, and no damage is visually observed. 2 ​ 4. The laminate according to claim 1 or 2, wherein the haze of the hard coat is 1.0% or less.

5. The laminate according to claim 1 or 2, wherein the haze of the laminate is 7% or less.

6. The laminate according to claim 1 or 2, wherein the hard coat is a cured product of a curable composition containing one or more curable compounds, and contains polyorganosilsesquioxane as the curable compound.

7. The laminate according to claim 6, wherein the curable composition contains a compound having one or more cationic polymerizable groups and one or more radical polymerizable groups in the molecule.

8. The laminate according to claim 6, wherein the curable composition further contains a curing catalyst.

9. The laminate according to claim 8, wherein the curing catalyst contains a cationic polymerization initiator.

10. The laminate according to claim 8, wherein the curing catalyst contains a radical polymerization initiator.

11. The laminate according to claim 6, wherein the curable composition further contains a radically curable polyorganosiloxane.

12. The laminate according to claim 6, wherein the curable composition further contains an aliphatic compound having two or more cationic polymerizable groups in the molecule.

13. The laminate according to claim 1 or 2, wherein the substrate is a transparent substrate.

14. The laminate according to claim 1 or 2, wherein the laminate has a surface protective film on at least one surface.

15. The laminate according to claim 1 or 2, wherein the laminate has the hard coat on one surface of the substrate and an adhesive layer on the other surface.

16. An image display device comprising the laminate according to claim 1 or 2.

17. The image display device according to claim 16, wherein the image display device is a foldable display.

18. The image display device according to claim 16, wherein the image display device is an organic electroluminescent display device.

19. A foldable device including the image display device according to claim 16.

Images