Laminated bodies, laminated films, image display devices, foldable devices

Abstract

[Problem] This invention provides a laminate capable of exhibiting sufficient flexibility without using compounds belonging to PFAS (per- and polyfluoroalkyl substances). [Solution] The laminate system of this invention comprises a substrate and a hard coating layer laminated on at least one side of the substrate, wherein the hard coating layer does not contain compounds belonging to PFAS; characterized in that: in a cylindrical mandrel test in which the surface of the hard coating layer of the laminate is bent in a convex manner, the minimum bending radius is 5 mm or less. Furthermore, it is preferable that the hard coating layer undergoes at least 10,000 cycles in a bending durability test until cracks appear in the hard coating layer.

Description

Technical Field

[0001] This invention relates to laminates, laminated films, image display devices, and foldable devices. Prior Technology

[0002] As a cover material for the outermost surface of displays or electronic materials used in televisions, computers, smartphones, etc., it is known to have a hard coating layer deposited to prevent damage. In particular, to achieve wear resistance, such hard coatings have conventionally used UV-curing resins incorporating cross-linked fluorine compounds (PFAS, per- and polyfluoroalkyl substances) (for example, Patent Document 1).

[0003] On the other hand, PFAS lacks biodegradability, and its long-term residue in the environment and toxicity have raised concerns. From the perspective of reducing environmental impact, the industry requires hard coatings that do not contain PFAS. [Previous Technical Documents] [Non-patent literature]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2016-11365 Summary of the Invention

[0005] [The problem that the invention aims to solve] However, in hard coatings that do not use PFAS, the flexibility is insufficient, making it difficult to produce hard coatings that exhibit the same flexibility as those containing PFAS.

[0006] The present invention addresses the aforementioned problems and aims to provide a laminate that can achieve sufficient flexibility without using compounds belonging to PFAS. [Technical means to solve the problem]

[0007] The inventors of this invention have discovered that a laminate having "a substrate and a hard coating layer deposited on at least one side of the substrate, wherein the hard coating layer does not contain compounds belonging to PFAS and satisfies specific physical property values" can achieve sufficient flexibility without the use of fluorine compounds. This invention was made based on these insights.

[0008] The present invention provides a laminate having a substrate and a hard coating layer laminated on at least one side of the substrate, wherein the hard coating layer does not contain a compound belonging to PFAS; and in a test of a cylindrical mandrel in which the hard coating layer of the laminate is bent in a manner that makes it convex, the minimum bending radius is 5 mm or less.

[0009] The aforementioned laminate is preferably a hard coating that, in the following bending durability test, undergoes more than 10,000 cycles until cracks appear in the hard coating. By having the above-described structure, it can achieve superior bending durability. Bending durability test: One repetition is defined as bending the laminate from its flattened state toward the surface of the hard coating at a bending radius of 4.0 mm by 180° and then flattening it again. This repetition is performed at a speed of 30 to 60 times per minute.

[0010] The aforementioned laminate is preferably one in which the hard coating, when subjected to a steel wool resistance test with a load of 750 g / cm² applied using #0000 steel wool and simultaneously rubbed back and forth 1000 times, shows no visible damage. With the above-described structure, it can achieve superior scratch resistance.

[0011] The aforementioned laminate is preferably characterized by a haze of 1.0% or less for the aforementioned hard coating.

[0012] The aforementioned laminated body preferably has a haze of 7% or less.

[0013] Furthermore, it is preferable that the above-mentioned hard coating is a hardened composition comprising one or more hardening compounds, and that the hardened composition comprises a polyorganosilsesquioxane as the hardening compound.

[0014] Furthermore, it is preferable that the aforementioned curing composition comprises a compound having one or more cationic polymeric groups and one or more free radical polymeric groups within its molecule.

[0015] Preferably, the aforementioned hardening composition further includes a hardening catalyst.

[0016] Preferably, the aforementioned hardening catalyst contains a cationic polymerization initiator.

[0017] Preferably, the aforementioned hardening catalyst contains a free radical polymerization initiator.

[0018] Preferably, the aforementioned curing composition further includes a free radical curing polyorganosiloxane.

[0019] Preferably, the aforementioned curing component is further contained within an aliphatic compound having two or more cationic polymeric groups.

[0020] Preferably, the aforementioned substrate is a transparent substrate.

[0021] The aforementioned laminate preferably has a surface protective film on at least one surface.

[0022] The aforementioned laminate preferably has the aforementioned hard coating on one side of the aforementioned substrate and an adhesive layer on the other side.

[0023] Furthermore, the present invention provides an image display device having the above-described laminate.

[0024] The aforementioned image display device is preferably a foldable display.

[0025] The aforementioned image display device is preferably an organic electroluminescent display device.

[0026] Furthermore, the present invention provides a foldable device that includes the above-described image display device. [Effects of the Invention]

[0027] The laminate of this invention can achieve sufficient flexibility without using compounds belonging to PFAS. Implementation

[0028] Furthermore, in this invention, "compounds belonging to PFAS" is a general term for perfluoroalkyl compounds and polyfluoroalkyl compounds.

[0029] [Laminated body] The laminated system of the present invention has a substrate and a hard coating layer laminated on at least one side of the substrate, wherein the hard coating layer does not contain any PFAS compounds. In a test on a cylindrical mandrel in which the hard coating surface of the laminated body is bent in a convex manner, the minimum bending radius is 5 mm or less. The laminated body of the present invention having the above-described structure can exhibit sufficient flexibility without containing any PFAS compounds.

[0030] The aforementioned laminate may have layers other than the aforementioned substrate and hard coating. Examples of such other layers include: a surface protective film, an adhesive layer, a primer layer for bonding the substrate and the hard coating, an anti-reflective layer, an anti-glare layer, a fingerprint-resistant layer, a stain-resistant layer, a scratch-resistant fingerprint layer, an antibacterial layer, a bonding layer, and a polarizing layer. These other layers may be formed on only one side (single-sided) of the aforementioned substrate, or on both sides (double-sided). Furthermore, when these other layers are formed on both sides of the aforementioned substrate, the same layer may be laminated separately, or layers of different thicknesses or compositions may be laminated separately.

[0031] The aforementioned surface protective film protects the surface of the aforementioned hard coating, and the aforementioned laminate preferably has a surface protective film on at least one surface. Furthermore, when the aforementioned hard coating is formed on both sides of the aforementioned substrate, the aforementioned surface protective film may be present on both surfaces of the aforementioned laminate.

[0032] As the aforementioned surface protective film, any known or conventional surface protective film can be used without particular limitation; for example, it can be used on the surface of a plastic film having an adhesive layer. Examples of such plastic films include those formed from polyester (polyethylene terephthalate, polyethylene naphthalate, etc.), polyolefins (polyethylene, polypropylene, cyclic polyolefins, etc.), polystyrene, acrylic resin, polycarbonate, epoxy resin, fluororesin, polysiloxane resin, diacetate resin, triacetate resin, polyarylate, polyvinyl chloride, polyurethane, polyether ether etherimide, polyimide, polyamide, and other plastic materials. Examples of adhesive layers include those formed from one or more well-known or conventional adhesives such as acrylic adhesives, polysiloxane adhesives, natural rubber adhesives, synthetic rubber adhesives, ethylene-vinyl acetate copolymer adhesives, ethylene-(meth)acrylate copolymer adhesives, styrene-isoprene block copolymer adhesives, and styrene-butadiene block copolymer adhesives. These adhesive layers may contain various additives (e.g., antistatic agents, slip agents, etc.). Furthermore, the plastic film and adhesive layer may each have a single-layer or multi-layer (multi-layer) structure. Also, the thickness of the surface protective film is not particularly limited and can be appropriately selected.

[0033] As for the aforementioned surface protective film, commercially available products such as the "SUNYTECT" series (manufactured by Sun A. Kaken Co., Ltd.), the "E-MASK" series (manufactured by Nitto Denko Co., Ltd.), the "MASTACK" series (manufactured by Fujimori Kogyo Co., Ltd.), the "HITALEX" series (manufactured by Hitachi Chemical Co., Ltd.), and the "ALPHAN" series (manufactured by Oji F-Tex Co., Ltd.) are available from the market.

[0034] Preferably, the adhesive layer is deposited on the side of the substrate opposite to the side with the hard coating layer in the laminate. That is, when the laminate has the adhesive layer, it is preferable that the hard coating layer is present on one side of the substrate and the adhesive layer is present on the other side. Furthermore, it is more preferable that the adhesive layer is present on one surface of the laminate.

[0035] As the adhesive constituting the aforementioned adhesive layer, the same adhesive as that exemplified in the aforementioned surface protective film can be used. Among these, acrylic adhesives and polysiloxane adhesives are preferred in terms of good transparency and sufficient adhesion even when the layer is relatively thin; acrylic adhesives are particularly preferred. Furthermore, only one type of adhesive may be used, or two or more types may be used.

[0036] The thickness of the aforementioned adhesive layer is, for example, 0.1 to 50 μm, preferably 1 to 45 μm, more preferably 2 to 40 μm, and even more preferably 5 to 35 μm.

[0037] The adhesive layer described above can be obtained by applying the adhesive to at least one side of a substrate and then curing it.

[0038] In a cylindrical mandrel test conducted according to JISK 5600-5-1, where the hard-coated surface is bent in a convex manner, the minimum bending diameter that will not produce cracks is 5 mm or less, preferably 4 mm or less. Sufficient flexibility can be achieved by using a minimum bending diameter of 5 mm or less. Furthermore, when the hard coating is present on both sides of the laminate, it is sufficient to satisfy the above-mentioned range on at least one side.

[0039] The aforementioned laminate is preferably designed to withstand a minimum bending diameter of 5 mm or less, more preferably 4 mm or less, and even more preferably 2 mm or less, without cracking during a cylindrical mandrel test performed in accordance with JISK 5600-5-1, by bending the hard-coated surface in a concave manner. Sufficient flexibility is achieved by limiting the minimum bending diameter to 5 mm or less. Furthermore, when the laminate has a hard coating on both sides, satisfying the above-mentioned range is sufficient for at least one side.

[0040] The aforementioned laminate preferably has a pencil hardness of F or higher, as measured according to JIS K5600-5-4, and more preferably H or higher. With a pencil hardness of F or higher, the surface hardness of the laminate becomes sufficient, making it easier to achieve wear resistance. Furthermore, when the double-sided surface layer of the aforementioned laminate has a hard coating, it is sufficient to satisfy the above-mentioned range on at least one side.

[0041] Preferably, the aforementioned laminate undergoes at least 10,000 cycles of bending durability testing until cracks appear in the hard coating layer, and more preferably at least 30,000 cycles without cracking. The bending durability test involves bending the laminate from a flattened state towards the hard coating layer with a bending radius of 4.0 mm at a direction of 180°, followed by flattening it again, as one cycle. This process is performed at a speed of 30-60 cycles per minute. With this configuration, sufficient bending durability can be achieved. Furthermore, when the laminate has a hard coating layer on both sides, meeting the above requirements on at least one side is sufficient.

[0042] Furthermore, the aforementioned laminate is preferably one in which no damage is detected on the surface of the hard coating when #0000 steel wool is applied back and forth 1000 times under a load of 750 g / cm². By having the above-mentioned structure, wear resistance can be achieved.

[0043] The haze value of the aforementioned laminate is preferably 7% or less, more preferably 5% or less, further preferably 3% or less, and even more preferably 1.5% or less. Furthermore, the lower limit of haze is, for example, 0.1%. By achieving a haze of 7% or less, it tends to be suitable for applications requiring high transparency. Moreover, in this specification, haze can be measured according to JIS K7136.

[0044] The total light transmittance of the aforementioned laminate is preferably 85% or higher, and more preferably 90% or higher. Achieving a total light transmittance of 85% or higher makes it suitable for applications requiring high transparency. Furthermore, in this specification, the total light transmittance can be measured according to JIS K7361-1.

[0045] The thickness of the aforementioned laminate is preferably 10 to 1000 μm, more preferably 30 to 500 μm, and even more preferably 50 to 300 μm. By making the thickness of the aforementioned laminate 10 μm or more, it becomes easier to achieve sufficient surface hardness. Furthermore, by making the thickness 1000 μm or less, it becomes easier to achieve sufficient flexibility.

[0046] <Substrate> As the substrate in the laminate of the present invention, known or conventional substrates such as plastic substrates, metal substrates, ceramic substrates, semiconductor substrates, glass substrates, paper substrates, wood substrates (wood-based substrates), and substrates with a coated surface can be used. Preferably, the substrate is a transparent substrate, and more preferably a plastic substrate. Furthermore, the substrate may be a single-layer structure or a multi-layer structure, and may be composed of one material or using two or more materials.

[0047] The plastic materials constituting the above-mentioned plastic substrates are not particularly limited, but may include: polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyimide; polycarbonate; polyamide; polyacetal; polyphenylene ether; polyphenylene sulfide; polyether ether; polyether ether ketone; homopolymers of nobornene monomers (addition polymers or ring-opening polymers, etc.); copolymers of nobornene monomers and olefin monomers such as copolymers of nobornene and ethylene (addition polymers or ring-opening polymers, etc., cyclic olefin copolymers). Cyclic polyolefins, such as polymers and their derivatives; vinyl polymers (e.g., acrylic resins such as polymethyl methacrylate (PMMA), polystyrene, polyvinyl chloride, acrylonitrile-styrene-butadiene resin (ABS resin), etc.); vinylidene polymers (e.g., polyvinylidene chloride, etc.); cellulose resins such as triacetyl cellulose (TAC); epoxy resins; phenolic resins; melamine resins; urea resins; maleimide resins; polysiloxane and other various plastic materials.

[0048] Among them, the plastic substrate is preferably a substrate with excellent transparency and bending durability, more preferably a polyester film (especially PET, PEN), polyimide film, cyclic polyolefin film, polycarbonate film, TAC film, PMMA film, and even more preferably a polyester film (especially PET, PEN) or polyimide film.

[0049] The aforementioned substrate may, as needed, contain antioxidants, ultraviolet absorbers, light stabilizers, heat stabilizers, nucleating agents, flame retardants, flame retardant additives, fillers, plasticizers, impact modifiers, reinforcing agents, dispersants, antistatic agents, foaming agents, antibacterial agents, and other additives. Furthermore, only one type of additive may be used, or two or more types may be used.

[0050] The surface of the substrate with the hard coating layer can be subjected to roughening treatment, adhesion enhancement treatment, antistatic treatment, sandblasting (grinding), corona discharge treatment, plasma treatment, chemical etching treatment, water mat treatment, flame treatment, acid treatment, alkali treatment, oxidation treatment, ultraviolet irradiation treatment, silane coupling agent treatment, and other known or conventional surface treatments. Furthermore, the plastic substrate can be an unstretched film, or a uniaxially stretched film, biaxially stretched film, or other stretched film. Moreover, commercially available products can be used as the substrate.

[0051] The thickness of the aforementioned substrate is preferably 1 to 1000 μm, more preferably 5 to 500 μm, even more preferably 10 to 400 μm, and even more preferably 10 to 300 μm.

[0052] Hard coating The aforementioned hard coating is preferably formed on one side (single-sided) of the laminate, which suppresses cracking of the laminate and simultaneously possesses sufficient surface hardness. Furthermore, the hard coating may also be formed on both sides (double-sided) of the substrate, but when the laminate has the aforementioned adhesive layer, it is preferable to form it on only one side of the substrate. Moreover, when a hard coating is formed on both sides of the substrate, it is sufficient that the following physical properties of the hard coating are satisfied on at least one side. Each hard coating may be laminated with the same layer, or with different thicknesses or compositions. Alternatively, a hard coating may be formed on one side of the substrate, and the other layers may be formed on the other side. From the viewpoint of suppressing cracking, it is preferable to form the hard coating on at least one side of the substrate, and the hard coating or the other layers on the other side.

[0053] The aforementioned hard coating is preferably formed from a hardened material comprising one or more hardening compounds. That is, the aforementioned hardening composition preferably comprises one or more hardening compounds. Only one type of hardening compound may be used, or two or more types may be used.

[0054] Examples of curing compounds include (meth)acrylate compounds, curing polysiloxane compounds, epoxy compounds, melamine compounds, vinyl ether compounds, and oxetane compounds. Preferably, the compound includes a curing polysiloxane, and more preferably, it includes a silsesquioxane, especially a polyorganosilsesquioxane. By including the polyorganosilsesquioxane, the curing composition is less prone to shrinkage during curing, thereby forming a hard coating with superior wear resistance. Furthermore, examples of silsesquioxanes include free radical polymerizable silsesquioxanes and cationic polymerizable silsesquioxanes, with cationic polymerizable silsesquioxanes being more preferred, and photocationic polymerizable silsesquioxanes being even more desirable.

[0055] The aforementioned free radical polymerizable silsesquioxanes possess intramolecular free radical polymerizable functional groups. Examples of such free radical polymerizable functional groups include (meth)acrylyl, (meth)acrylamine, vinyl, and vinyl thioyl.

[0056] The aforementioned cationic polymerizable silsesquioxane has a cationic polymerizable functional group within its molecule. Examples of such cationic polymerizable functional groups include epoxy groups, oxetane groups, vinyl ether groups, and vinylphenyl groups. Among these, epoxy groups are preferred from the viewpoint of enabling higher surface hardness of the hard coating.

[0057] As a group containing the above-mentioned epoxy group, well-known or conventional groups having an ethylene oxide ring can be cited as examples, and there is no particular limitation. From the viewpoint of the curability of the curable composition and the heat resistance of the hard coating, it is preferred to be a group represented by the following formula (1a), a group represented by the following formula (1b), a group represented by the following formula (1c), a group represented by the following formula (1d), more preferably a group represented by the following formula (1a), a group represented by the following formula (1c), and even more preferably a group represented by the following formula (1a).

[0058] In formula (1a) above, R1a represents a straight-chain or branched alkyl group. Examples of straight-chain or branched alkyl groups include methylene, methylmethylene, dimethylmethylene, ethyl alkyl group, propyl alkyl group, trimethylene, tetramethylene, pentamethylene, hexamethylene, decamethylene, and other straight-chain or branched alkyl groups with 1 to 10 carbon atoms. Among these, from the viewpoint of the curability of the curable composition, R1a is preferably a straight-chain alkyl group with 1 to 4 carbon atoms, or a branched alkyl group with 3 or 4 carbon atoms, more preferably ethyl alkyl group, trimethylene group, or propyl alkyl group, and even more preferably ethyl alkyl group or trimethylene group.

[0059] In formula (1b) above, R1b represents a straight-chain or branched alkyl group, which can be exemplified by the same group as R1a. Among them, as R1b, from the viewpoint of the curability of the curable composition, it is more preferably a straight-chain alkyl group with 1 to 4 carbons, a branched alkyl group with 3 or 4 carbons, more preferably ethyl, trimethylene, or propyl, and even more preferably ethyl or trimethylene.

[0060] In the above formula (1c), R1c represents a straight-chain or branched alkyl group, which can be exemplified by the same group as R1a. Among them, as R1c, from the viewpoint of the curability of the curable composition, it is more preferably a straight-chain alkyl group with 1 to 4 carbons, a branched alkyl group with 3 or 4 carbons, more preferably ethyl, trimethylene, or propyl, and even more preferably ethyl or trimethylene.

[0061] In the above formula (1d), R1d represents a straight-chain or branched alkyl group, which can be exemplified by the same group as R1a. Among them, as R1d, from the viewpoint of the curability of the curable composition, it is more preferably a straight-chain alkyl group with 1 to 4 carbons, a branched alkyl group with 3 or 4 carbons, more preferably ethyl, trimethylene, or propyl, and even more preferably ethyl or trimethylene.

[0062] R1 in formula (1) is preferably represented by the above formula (1a) and R1a is an ethyl group [wherein, 2-(3,4-epoxycyclohexyl)ethyl].

[0063] Examples of cationic polymerizable silsesquioxanes include compounds having structural units represented by the following formula (1). [R1SiO3 / 2] (1)

[0064] The structural unit represented by the above formula (1) is usually represented by the silsesquioxane structural unit (so-called T unit) represented by [RSiO3 / 2]. Furthermore, R in the above formula represents a hydrogen atom or a monobasic organic group, and the same applies below. The structural unit represented by the above formula (1) is formed by the hydrolysis and condensation reaction of the corresponding hydrolyzable trifunctional silane compound. Furthermore, in this specification, a compound having the structural unit represented by the above formula (1) is sometimes referred to as "silsesquioxane (X)". R1 in formula (1) represents a group containing the above-mentioned cationic polymerizable functional group (monobasic group).

[0065] Silsesquioxane (X) may have only one structural unit represented by the above formula (1), or it may have two or more structural units represented by the above formula (1).

[0066] As a silsesquioxane structural unit [RSiO3 / 2], in addition to the structural unit represented by the above formula (1), silsesquioxane (X) may also have a structural unit represented by the following formula (2). [R2SiO3 / 2] (2)

[0067] The structural unit represented by the above formula (2) is usually a silsesquioxane structural unit (T unit) represented by [RSiO3 / 2]. That is, the structural unit represented by the above formula (2) is formed by the hydrolysis and condensation reaction of the corresponding hydrolytic trifunctional silane compound.

[0068] In formula (2) above, R2 represents 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. Examples of aryl groups include phenyl, tolyl, and naphthyl. Examples of aralkyl groups include benzyl and phenethyl. Examples of cycloalkyl groups include cyclobutyl, cyclopentyl, and cyclohexyl. Examples of alkyl groups include straight-chain or branched alkyl groups such as methyl, ethyl, propyl, n-butyl, isopropyl, isobutyl, secondary butyl, tertiary butyl, and isopentyl.

[0069] As for the aforementioned substituted aryl, substituted aralkyl, substituted cycloalkyl, and substituted alkyl groups, examples can be given where the hydrogen atom or part or all of the main chain backbone of each of the aforementioned aryl, aralkyl, cycloalkyl, and alkyl groups is replaced by at least one group selected from the group consisting of alkyl (especially straight-chain or branched alkyl with 1 to 10 carbon atoms), ether, ester, carbonyl, siloxyalkyl, halogen atom (fluorine atom, etc.), mercapto, amino, and hydroxyl (hydroxyl).

[0070] R2 is preferably a substituted or unsubstituted aryl group, a substituted or unsubstituted alkyl group, more preferably a substituted or unsubstituted aryl group, and even more preferably a phenyl group.

[0071] The ratio of the aforementioned silsesquioxane structural units (the structural units represented by formula (1) and the structural units represented by formula (2)) in silsesquioxane (X) can be appropriately adjusted by the composition of the raw materials (hydrolyzable trifunctional silanes) used to form these structural units.

[0072] The silsesquioxane (X) is preferably a structural unit comprising at least R1, which is a group containing an alicyclic epoxy group, represented by formula (1) above, and R2, which is an aryl group that may have substituents, represented by formula (2) above. In this case, the hard coating tends to have better surface hardness, flexibility, processability, and flame retardancy.

[0073] In addition to the structural units represented by equation (1) and equation (2) above, which are T units, silsesquioxanes (X) may further have at least one siloxane structural unit selected from the group consisting of structural units represented by [R3SiO1 / 2] (so-called M unit), structural units represented by [R2SiO2 / 2] (so-called D unit), and structural units represented by [SiO4 / 2] (so-called Q unit). Furthermore, R in the above-mentioned M unit and D unit may be the same as R1 in the structural unit represented by equation (1) above and R2 in the structural unit represented by equation (2) above. As for silsesquioxane structural units other than the structural units represented by equation (1) and equation (2) above, for example, the structural unit represented by the following equation (3) can be cited. [HSiO3 / 2] (3)

[0074] The silsesquioxane (X) comprises a structural unit (T3 body) represented by formula (I) below. It may further comprise a structural unit (T2 body) represented by formula (II) below. [RaSiO3 / 2] (I) [RbSiO2 / 2(ORc)] (II)

[0075] Furthermore, if the structural unit represented by the above formula (I) is described in more detail, it is represented by the following formula (I'). Also, 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 bonded to other silicon atoms (silicon atoms not shown in 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 bonded to other silicon atoms (silicon atoms not shown in formula (II')). That is, both the above-mentioned T3 and T2 bodies are structural units (T units) formed by the hydrolysis and condensation reactions of the corresponding hydrolyzable trifunctional silane compounds.

[0076] In formula (I) above, Ra (the same applies to Ra in formula (I') and in formula (II) above, Rb (the same applies to Rb in formula (II')) 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 specific examples of Ra and Rb, those identical to R1 in formula (1) above and R2 in formula (2) above can be shown. Furthermore, Ra in formula (I) and Rb in formula (II) are respectively derived from the groups (excluding alkoxy and halogen atoms) of the silicon atom in the hydrolytic trifunctional silane compound used as a raw material for silsesquioxane (X), or, for example, in the case where the above-mentioned cationic polymerizable functional group is an epoxy group, the groups are obtained by epoxidation of the groups (excluding alkoxy and halogen atoms) of the silicon atom in the hydrolytic trifunctional silane compound used as a raw material for silsesquioxane (X).

[0077] In formula (II) above, Rc (and Rc in formula (II') represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Examples of alkyl groups having 1 to 4 carbon atoms include straight-chain or branched alkyl groups with 1 to 4 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, and isobutyl. Among these, methyl and ethyl are preferred, and methyl is even more preferred. The alkyl group in Rc of formula (II) is usually derived from the alkyl group of the alkoxy group in the hydrolyzable silane compound used as a raw material for silsesquioxane (X).

[0078] The molar ratio [structure unit represented by formula (I) / structure unit represented by formula (II)] (sometimes referred to as "T3 body / T2 body") of the structural unit (T3 body) represented by formula (II) in the silsesquioxane (X) is not particularly limited, but is 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 especially preferably 8 to 14. By making the above molar ratio [T3 body / T2 body] 5 or more, there is a tendency to further improve the surface hardness of the hard coating.

[0079] The molar ratio [T3 body / T2 body] in silsesquioxane (X) can be determined, for example, by 29Si-NMR spectroscopy. In the 29Si-NMR spectrum, silicon atoms in the structural unit (T3 body) represented by formula (I) and silicon atoms in the structural unit (T2 body) represented by formula (II) show signals (peaks) at different positions (chemical shifts). Therefore, the molar ratio [T3 body / T2 body] can be determined by calculating the integral ratio of these peaks. Specifically, for example, when a silsesquioxane (X) has a structural unit represented by formula (1) above and R1 is a 2-(3,4-epoxycyclohexyl)ethyl, the signal of silicon atoms in the structure represented by formula (I) above (T3 body) appears at -64 to -70 ppm, and the signal of silicon atoms in the structure represented by formula (II) above (T2 body) appears at -54 to -60 ppm. Therefore, in this case, by calculating the integral ratio of the signal at -64 to -70 ppm (T3 body) and the signal at -54 to -60 ppm (T2 body), the above molar ratio [T3 body / T2 body] can be obtained.

[0080] The 29Si-NMR spectrum of silsesquioxane (X) can be determined, for example, by means of the following apparatus and conditions. Measurement device: Trade name "JNM-ECA500NMR" (manufactured by Japan Electronics Corporation) Solvent: deuterium chloroform Total number of times: 1800 Measurement temperature: 25℃

[0081] A molar ratio [T3 body / T2 body] of 5 or more for silsesquioxane (X) means that, relative to the T3 body, there is a fixed amount or more of T2 body in silsesquioxane (X). Examples of such T2 body include: structural units represented by the following formula (4), structural units represented by the following formula (5), and structural units represented by the following formula (6). R1 ​​in the following formula (4) and R2 in the following formula (5) are the same as R1 in the following formula (1) and R2 in the following formula (2), respectively. Rc in the following formulas (4) to (6) are the same as Rc in formula (II), representing hydrogen atoms or alkyl groups having 1 to 4 carbon atoms. [R1SiO2 / 2(ORc)] (4) [R2SiO2 / 2(ORc)] (5) [HSiO2 / 2(ORc)] (6)

[0082] Cationic polymerizable silsesquioxanes (especially silsesquioxane (X)) can be silsesquioxanes with a cage-like shape (cage-like silsesquioxanes). Cage-like silsesquioxanes include fully cage-like silsesquioxanes and incompletely cage-like silsesquioxanes, wherein incompletely cage-like silsesquioxanes are preferred.

[0083] Typically, a fully cage-like silsesquioxane is a polyorganosilsesquioxane composed solely of the T3 phase, with no T2 phase present in the molecule. This implies that silsesquioxanes with a molar ratio [T3 / T2] of 5 or higher, and exhibiting an intrinsic absorption peak near 1100 cm⁻¹ in the FT-IR spectrum as described below, possess an incomplete cage-like silsesquioxane structure.

[0084] Whether silsesquioxane (X) possesses a cage-like (incomplete cage-like) silsesquioxane structure can be confirmed using FT-IR spectroscopy [Reference: RHRaney, M. Itoh, A. Sakakibara and T. Suzuki, Chem. Rev. 95, 1409 (1995)]. Specifically, in the FT-IR spectrum, the presence of no intrinsic absorption peaks near 1050 cm⁻¹ and 1150 cm⁻¹, and a single intrinsic absorption peak near 1100 cm⁻¹, indicates that silsesquioxane (X) possesses a cage-like (incomplete cage-like) silsesquioxane structure. In contrast, the presence of intrinsic absorption peaks near 1050 cm⁻¹ and 1150 cm⁻¹ in the FT-IR spectrum typically indicates a ladder-like silsesquioxane structure. Furthermore, the FT-IR spectrum of silsesquioxane (X) can be determined, for example, by means of the following apparatus and conditions. Measuring device: Product name "FT-720" (manufactured by Horiba Manufacturing Co., Ltd.) Measurement method: Penetration method Resolution: 4 cm⁻¹ Wavenumber range: 400~4000 cm⁻¹ Total number of times: 16

[0085] The ratio (total) of structural units having cationic polymerizable functional groups (e.g., structural units represented by formula (1) above, structural units represented by formula (4) above, etc.) to the total amount of siloxane structural units in the cationic polymerizable silsesquioxane [total amount of all siloxane structural units; M units, D units, T units and Q units] (100 mol%) is not particularly limited, but is preferably 50 mol% or more (e.g., 50 to 100 mol%), more preferably 55 to 100 mol%, more preferably 65 to 99.9 mol%, and even more preferably 80 to 99 mol%, particularly preferably 90 to 98 mol%. By having the above ratio of 50 mol% or more, the curability of the curable composition is improved, or the surface hardness of the hard coating is significantly increased. Furthermore, the ratio of each siloxane structural unit in cationic polymerizable silsesquioxanes can be calculated, for example, by means of the composition of the raw materials or by NMR spectroscopy.

[0086] The ratio of the structural unit (T3 body) represented by the above formula (I) to the total amount of siloxane structural units in the silsesquioxane (X) [total amount of all siloxane structural units; M units, D units, T units and Q units] (100 mol%) is not particularly limited, but is preferably 50 mol% or more, more preferably 60 to 99 mol%, and even more preferably 70 to 98 mol%, even more preferably 80 to 95 mol%, and even more preferably 85 to 92 mol%. It is speculated that by making the ratio of the structural unit of the T3 body 50 mol% or more, it becomes easier to form an incomplete cage shape with an appropriate molecular weight, and therefore there is a tendency to further improve the surface hardness of the hard coating.

[0087] The ratio (total) of the structural unit represented by equation (2) and the structural unit represented by equation (5) above relative to the total amount of siloxane structural units in silsesquioxane (X) [total amount of all siloxane structural units; M units, D units, T units and Q units] (100 mol%) is not particularly limited, but is preferably 0 to 50 mol%, more preferably 0 to 40 mol%, and even more preferably 0 to 30 mol%, and even more preferably 1 to 15 mol%. By making the above ratio 50 mol% or less, the ratio of structural units with cationic polymerizable functional groups can be relatively increased, thus improving the hardening properties of the hardening composition and tending to further increase the surface hardness of the hard coating.

[0088] The ratio (total amount) of the structural unit represented by formula (I) and the structural unit represented by formula (II) above relative to the total amount of siloxane structural units in the silsesquioxane (X) [total amount of all siloxane structural units; M units, D units, T units and Q units] (100 mol%) (especially the combined ratio of T3 body and T2 body) is not particularly limited, but preferably 60 mol% or more (e.g., 60~100 mol%), more preferably 70 mol% or more, further preferably 80 mol% or more, and especially preferably 90 mol% or more. It is speculated that by making the above ratio 60 mol% or more, it becomes easier to form an incomplete cage shape with an appropriate molecular weight, and therefore there is a tendency to further improve the surface hardness of the hard coating. It is particularly desirable that 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.

[0089] The number average molecular weight (Mn) of silsesquioxane (X) converted from standard polystyrene using gel permeation chromatography is not particularly limited, but is preferably 1000-3000, more preferably 1000-2800, even more preferably 1100-2600, and especially preferably 1500-2500. By having a number average molecular weight of 1000 or higher, there is a tendency to further improve the surface hardness of the hard coating. Alternatively, there is a tendency to improve the heat resistance and abrasion resistance of the hard coating. On the other hand, by having a number average molecular weight of 3000 or lower, there is a tendency to improve compatibility with other components in the curing composition, and thus improve the heat resistance of the hard coating.

[0090] The molecular weight dispersion (Mw / Mn) of silsesquioxane (X) converted from standard polystyrene using gel permeation chromatography is not particularly limited, but is preferably 1.0 to 3.0, more preferably 1.1 to 2.0, even more preferably 1.2 to 1.9, even more preferably 1.3 to 1.8, and particularly preferably 1.45 to 1.80. By achieving a molecular weight dispersion of 3.0 or less, there is a tendency to further increase the surface hardness of the hard coating. On the other hand, by achieving a molecular weight dispersion of 1.0 or more (especially 1.1 or more), there is a tendency to easily form a liquid, thus improving processability.

[0091] Furthermore, the number-average molecular weight and molecular weight dispersion of silsesquioxane (X) can be determined using the following apparatus and conditions. Measuring device: Trade name "LC-20AD" (manufactured by Shimadzu Corporation) Tube Strings: 2 Shodex KF-801, KF-802 and KF-803 (manufactured by Showa Denko Co., Ltd.) Measurement temperature: 40℃ Solution: THF, sample concentration 0.1~0.2% by mass Flow rate: 1 mL / min Detector: UV-VIS detector (trade name "SPD-20A", manufactured by Shimadzu Corporation) Molecular weight: Conversion to standard polystyrene

[0092] Cationic polymerizable silsesquioxanes can be manufactured using well-known or conventional methods for manufacturing silsesquioxanes without particular limitation. For example, they can be manufactured by hydrolyzing and condensing one or more hydrolyzable silane compounds.

[0093] The content ratio of the polyorganosilicone silsesquioxane in the aforementioned curing composition is not particularly limited, but relative to the total amount of the curing compound (100% by mass), it is preferably more than 50% by mass (e.g., more than 50% by mass and less than 98% by mass), more preferably 60-96% by mass, further preferably 70-95% by mass, and even more preferably 80-93% by mass. When the above content ratio exceeds 50% by mass, there is a tendency to further improve the surface hardness of the hard coating. When the above content ratio is less than 98% by mass, there is a tendency to include other components, thereby further improving the effects obtained by including them. Furthermore, there is a tendency to include a curing catalyst, thereby enabling more efficient curing of the curing composition.

[0094] The aforementioned curing component is preferably a compound containing one or more cationic polymeric groups and one or more free radical polymeric groups within its molecule (hereinafter, sometimes referred to as "compound A"). By including compound A in the aforementioned curing component, the crosslinking density during the preparation of the cured material can be effectively increased, making it easier to impart higher surface hardness, excellent flexibility and flexural durability to the hard coating, and preventing the antifouling performance from being reduced. Furthermore, only one type of compound A may be used, or two or more types may be used.

[0095] Compound A may contain "cationic polymerizable groups" such as epoxy, oxobutyl, vinyl ether, and hydroxyl groups. From the viewpoint of suppressing the reduction of surface hardness, flexibility, and flexural durability of the hard coating, epoxy groups are preferred. Furthermore, when compound A has two or more cationic polymerizable groups, these cationic polymerizable groups may be the same or different.

[0096] Compound A may contain "free radical polymerizable groups" such as (meth)acrylyl or vinyl groups. From the viewpoint of surface hardness and flexural durability of the hard coating, (meth)acrylyl is preferred. Furthermore, when compound A has two or more free radical polymerizable groups, these free radical polymerizable groups may be the same or different.

[0097] The number of cationic polymerizable groups in one molecule of compound A is not particularly limited, but preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 or 2. Similarly, the number of free radical polymerizable groups in one molecule of compound A is not particularly limited, but preferably 1 to 5, more preferably 1 to 3, and even more preferably 1 or 2.

[0098] The functional group equivalent of the cationic polymerizable group of compound A is not particularly limited, but is preferably 50 to 500, more preferably 80 to 480, and even more preferably 120 to 450. When the functional group equivalent is 50 or more, it becomes easier to achieve sufficient flexural durability of the hard coating. When the functional group equivalent is 500 or less, sufficient surface hardness of the hard coating can be achieved. Furthermore, the functional group equivalent of the cationic polymerizable group of compound A can be calculated by the following formula. [Functional equivalent of cationic polymerizable groups] = [Molecular weight of compound A] / [Number of cationic polymerizable groups in compound A]

[0099] The functional group equivalent of the free radical polymerizable group of compound A is not particularly limited, but is preferably 50 to 500, more preferably 80 to 480, and even more preferably 120 to 450. When the functional group equivalent is 50 or more, it becomes easier to achieve sufficient flexural durability of the hard coating. When the functional group equivalent is 500 or less, sufficient surface hardness of the hard coating can be achieved. Furthermore, the functional group equivalent of the free radical polymerizable group of compound A can be calculated by the following formula. [Functional group equivalent of free radical polymerizability] = [Molecular weight of compound A] / [Number of free radical polymerizability groups possessed by compound A]

[0100] Specifically, examples of compound A include: 3,4-epoxycyclohexyl methyl methacrylate, glycidyl methacrylate, tripropylene glycol diglycidyl ether di(meth)acrylate (a compound obtained by reacting (meth)acrylate with two epoxy groups of tripropylene glycol diglycidyl ether), tripropylene glycol diglycidyl ether hemi(meth)acrylate (a compound obtained by reacting (meth)acrylate with one epoxy group of tripropylene glycol diglycidyl ether), bisphenol A epoxy di(meth)acrylate (a compound obtained by reacting (meth)acrylate with two epoxy groups of bisphenol A diglycidyl ether), bisphenol A epoxy hemi(meth)acrylate (a compound obtained by reacting (meth)acrylate or its derivatives with one epoxy group of bisphenol A diglycidyl ether), bisphenol F epoxy di(meth)acrylate, bisphenol F epoxy hemi(meth)acrylate, bisphenol S epoxy di(meth)acrylate, bisphenol S epoxy hemi(meth)acrylate, and bisphenol S epoxy hemi(meth)acrylate. Acrylic esters are compounds containing an epoxy group and a (meth)acrylic acid group within one molecule; 3-oxetane butyl methyl methacrylate, 3-methyl-3-oxetane methyl methacrylate, 3-ethyl-3-oxetane methyl methacrylate, 3-butyl-3-oxetane methyl methacrylate, 3-hexyl-3-oxetane methyl methacrylate are compounds containing an oxetane butyl group and a (meth)acrylic acid group within one molecule; 2-ethyleneoxyethyl methacrylate, 3-ethyleneoxypropyl methacrylate, 1-methyl-2-ethyleneoxyethyl methacrylate, 2-ethyleneoxypropyl methacrylate, 4-ethyleneoxybutyl methacrylate, 1-methyl-3-ethyleneoxypropyl methacrylate, 1-ethyleneoxymethylpropyl methacrylate, 2-methyl-3-ethyleneoxypropyl methacrylate, 1,1-Dimethyl-2-ethyleneoxyethyl ester, 3-ethyleneoxybutyl acrylate, 1-methyl-2-ethyleneoxypropyl acrylate, 2-ethyleneoxybutyl acrylate, 4-ethyleneoxycyclohexyl acrylate, 6-ethyleneoxyhexyl acrylate, 4-ethyleneoxymethylcyclohexyl acrylate, 3-ethyleneoxymethylcyclohexyl acrylate, 2-ethyleneoxycyclohexyl acrylate, p-ethyleneoxymethylphenyl acrylate, m-ethyleneoxymethylphenyl acrylate, o-ethyleneoxymethylphenyl acrylate 2-(ethoxyethoxy)ethyl methacrylate, 2-(ethoxyisopropoxy)ethyl methacrylate, 2-(ethoxyethoxy)propyl methacrylate, 2-(ethoxyethoxy)isopropyl methacrylate, 2-(ethoxyisopropoxy)propyl methacrylate, 2-(ethoxyisopropoxy)isopropyl methacrylate, 2-(ethoxyethoxyethoxy)ethyl methacrylate, 2-(ethoxyethoxyisopropoxy)ethyl methacrylate, 2-(ethoxyisopropoxyethoxy)ethyl methacrylate, 2-(ethoxyethoxyethoxy)ethyl methacrylate, 2-(ethoxyethoxy)isopropoxyethoxy)ethyl methacrylate, 2-(ethoxyethoxy)ethyl methacrylate 2-(ethyleneoxyethoxyethoxy)propyl acrylate, 2-(ethyleneoxyethoxyethoxy)propyl acrylate, 2-(ethyleneoxyethoxyisopropoxy)propyl acrylate, 2-(ethyleneoxyisopropoxyethoxy)propyl acrylate, 2-(ethyleneoxyisopropoxyisopropoxy)propyl acrylate, 2-(ethyleneoxyethoxyethoxy)isopropyl acrylate, 2-(ethyleneoxyethoxyisopropoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyethoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyethoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyisopropoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyisopropoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyisopropoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyisopropoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyisopropoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyisopropoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyisopropoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyisopropoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyisopropoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxyisopropoxy)isopropyl acrylate, 2-(ethyleneoxyisopropoxy) ... Compounds containing both an vinyl ether group and a (meth)acrylic acid group within one molecule include 2-(vinyloxyethoxyethoxyethoxy)ethyl acrylate, 2-(vinyloxyethoxyethoxyethoxy)ethyl acrylate, 2-(isopropenyloxyethoxyethoxy)ethyl acrylate, 2-(isopropenyloxyethoxyethoxyethoxy)ethyl acrylate, 2-(isopropenyloxyethoxyethoxyethoxyethoxy)ethyl acrylate, polyethylene glycol monovinyl ether of methacrylic acid, and polyethylene glycol monovinyl ether of methacrylic acid.

[0101] From the viewpoint of the bending durability and surface hardness of the hard coating, compound A is preferably a compound that has an epoxy group as a cationic polymerizable group within one molecule and a (meth)acrylic group as a free radical polymerizable group. Specifically, it is preferably 3,4-epoxycyclohexyl methyl methacrylate, glycidyl methacrylate, tripropylene glycol diglycidyl ether hemi(meth)acrylate, bisphenol A epoxy hemi(meth)acrylate, bisphenol F epoxy hemi(meth)acrylate, bisphenol S epoxy hemi(meth)acrylate, etc.

[0102] Compound A can be manufactured by well-known methods, such as by reacting a portion of the cationic polymerizable group (e.g., epoxy group) of a compound having two or more cationic polymerizable groups within one molecule with a carboxylic acid (e.g., acrylic acid, methacrylic acid, etc.) or its derivative having a free radical polymerizable group. Furthermore, as the aforementioned compound A, commercially available products under trade names such as "LIGHT ESTER G", "EPOXYESTER 200PA", "EPOXYESTER 200PA-E5" (manufactured by Kyoei Chemical Co., Ltd.), and "NK OLIGO EA1010N" (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) can also be used.

[0103] The content ratio of compound A in the above-mentioned curing composition is not particularly limited, but it is preferably 0.05 to 8% by mass, more preferably 0.1 to 5% by mass, and even more preferably 0.2 to 3% by mass, relative to the total amount of curing compound (100% by mass). When the above content ratio is within the above range, the surface of the hard coating has better resistance to sebum adhesion.

[0104] The content (admixture amount) of compound A in the aforementioned hardening composition is not particularly limited. As a solid component, it is preferably 1 to 100 parts by mass relative to 100 parts by mass of the aforementioned polyorganosilicone silsesquioxane, more preferably 1.5 to 75 parts by mass, and even more preferably 2 to 50 parts by mass. By making the content of compound A 1 part by mass or more, there is a tendency to further improve the flexibility and flexural durability of the hard coating. On the other hand, by making the content of compound A 100 parts by mass or less, there is a tendency to maintain the surface hardness of the hard coating.

[0105] Furthermore, the aforementioned curing component is preferably an aliphatic compound (hereinafter, sometimes referred to as compound (B)) containing two or more cationic polymeric groups within its molecule. By including compound B, the hard coating can be given flexibility, making it easier to achieve bendability and flexural durability. Moreover, compound (B) is a compound that does not belong to the aforementioned polyorganosilicone silsesquioxane and compound (A). As compound (B), only one type may be used, or two or more types may be used.

[0106] As the aforementioned cationic polymerizable group, examples can be the same as those exemplified in compound (A). Examples include epoxy, oxobutyl, and vinyl ether groups. From the viewpoint of achieving the surface hardness, flexibility, and flexural durability of the aforementioned hard coating, epoxy is preferred; from the viewpoint of reactivity, epoxypropyl is more preferred. Furthermore, the two or more cationic polymerizable groups in compound B can be identical or different.

[0107] The number of cationic polymerizable groups in one molecule of compound B is two or more, and there is no particular limitation. For example, it is preferred to have two to five, more preferably two to three, and even more preferably two.

[0108] The functional group equivalent of the cationic polymerizable group of compound B is not particularly limited, but is preferably 50 to 500, more preferably 80 to 480, and even more preferably 120 to 450. When the functional group equivalent is 50 or more, it becomes easier to achieve sufficient flexural durability of the hard coating. When the functional group equivalent is 500 or less, sufficient surface hardness of the hard coating can be achieved. Furthermore, the functional group equivalent of the cationic polymerizable group of compound B can be calculated by the following formula. [Functional group equivalent of cationic polymerizable group] = [Molecular weight of compound B] / [Number of thermopolymerizable functional groups possessed by compound B]

[0109] The "aliphatic compound" in compound B refers to an aliphatic compound that does not have a cyclic structure, excluding the aforementioned cationic polymerizable groups. Examples of compound B include: glycidyl ether of a di- or higher alcohol that does not have a cyclic structure; glycidyl ester of a di- or higher carboxylic acid [e.g., adipic acid, sebacic acid, maleic acid, itaconic acid, etc.]. Examples of the aforementioned di- or higher alcohols that do not have a cyclic structure include: 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, etc.; and tri- or higher polyols such as glycerol, diglycerol, erythritol, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol, etc. Furthermore, alcohols with two or more components can also be polyether polyols, polyester polyols, polycarbonate polyols, polyolefin polyols, etc.

[0110] Furthermore, compound B is preferably a compound having cationic polymerizable groups at both ends, specifically, it is preferably an aliphatic epoxy propylene ether type epoxy compound.

[0111] Examples of aliphatic epoxy ether type epoxy compounds include: ethylene glycol diepoxide ether, diethylene glycol diepoxide ether, triethylene glycol diepoxide ether, etc. (poly)alkyl glycol diepoxide ethers; 1,6-hexanediol diepoxide ether, etc. Commercially available aliphatic epoxy ether type epoxy compounds include: trade names "EPOLIGHT 40E", "EPOLIGHT 100E", "EPOLIGHT 200E", "EPOLIGHT 400E", "EPOLIGHT 1600N" (manufactured by Kyoei Chemical Co., Ltd.), and trade name "YH-300" (manufactured by Nippon Steel Chemical & Material Co., Ltd.).

[0112] The content ratio of compound (B) in the above-mentioned curing composition is not particularly limited, but it is preferably 1 to 20% by mass, more preferably 2 to 15% by mass, and even more preferably 3 to 10% by mass, relative to the total amount of curing compound (100% by mass). When the above-mentioned content ratio is within the above range, the flexibility and bending resistance of the hard coating become more suitable.

[0113] The content of compound (B) is not particularly limited, but is preferably 1 to 20 parts by mass relative to 100 parts by mass of the above-mentioned polyorganosilicone silsesquioxane, more preferably 2 to 15 parts by mass, and even more preferably 3 to 10 parts by mass. When the above content is within the above range, the flexibility and bending resistance of the hard coating become more suitable.

[0114] The aforementioned curing component preferably includes a curing catalyst. The curing catalyst is a compound capable of initiating or promoting the polymerization reaction of the aforementioned polyorganosilicon silsesquioxane, compound (A), and compound (B), etc., of the curing compounds. Only one type of curing catalyst may be used, or two or more types may be used.

[0115] As the aforementioned curing catalyst, it can be selected according to the type of curing functional groups possessed by the curing compound, among which, cationic polymerization initiators and / or free radical polymerization initiators are preferred. The aforementioned cationic polymerization initiator is a compound that generates cationic species by irradiation with heat or active energy lines, thereby initiating the curing reaction of the curing compound.

[0116] Examples of cationic polymerization initiators include photocationic polymerization initiators (photoacid generators) and thermal cationic polymerization initiators (thermal acid generators).

[0117] As the aforementioned photocationic polymerization initiator, well-known or conventional photocationic polymerization initiators can be used, such as: strontium salts (salts of strontium ions and anions), ferrous salts (salts of ferrous ions and anions), selenium salts (salts of selenium ions and anions), ammonium salts (salts of ammonium ions and anions), phosphonium salts (salts of phosphonium ions and anions), salts of transition metal complex ions and anions, etc.

[0118] Examples of strontium salts mentioned above include: triphenylstrontium salt, tri-p-tolylstrontium salt, tri-o-tolylstrontium salt, tris(4-methoxyphenyl)strontium salt, 1-naphthyldiphenylstrontium salt, 2-naphthyldiphenylstrontium salt, tris(4-fluorophenyl)strontium salt, tri-1-naphthylstrontium salt, tri-2-naphthylstrontium salt, tris(4-hydroxyphenyl)strontium salt, diphenyl[4-(phenylthio)phenyl]strontium salt, and 4-(p-tolylthio)phenyldi-( Triaryl strontium salts such as p-phenyl strontium salt; diaryl strontium salts such as diphenylbenzylmethyl strontium salt, diphenyl-4-nitrobenzylmethyl strontium salt, diphenylbenzyl strontium salt, and diphenylmethyl strontium salt; monoaryl strontium salts such as phenylmethylbenzyl strontium salt, 4-hydroxyphenylmethylbenzyl strontium salt, and 4-methoxyphenylmethylbenzyl strontium salt; and trialkyl strontium salts such as dimethylbenzylmethyl strontium salt, benzomethyltetrahydrothiophenonium salt, and dimethylbenzyl strontium salt.

[0119] Examples of diphenyl[4-(phenylthio)phenyl]sulphine salts include diphenyl[4-(phenylthio)phenyl]sulphine tetra(pentafluorophenyl)borate and diphenyl[4-(phenylthio)phenyl]sulphine hexafluorophosphate. Alternatively, commercially available products such as "CPI-100P" (manufactured by SAN-APRO Co., Ltd., 50% propylene carbonate solution of diphenyl[4-(phenylthio)phenyl]sulphine hexafluorophosphate) can also be used.

[0120] Examples of the aforementioned monoxide salts include: trade name "RHODORSIL PHOTOINITIATOR 2074" (manufactured by RHODIA JAPAN Co., Ltd., tetra(pentafluorophenyl)borate-[(1-methylethyl)phenyl](methylphenyl)monoxide), trade name "WPI-124" (manufactured by Wako Pure Chemical Industries Co., Ltd.), diphenyl monoxide, di-p-tolyl monoxide, bis(4-dodecylphenyl) monoxide, bis(4-methoxyphenyl) monoxide, etc.

[0121] Examples of the aforementioned selenium salts include: triphenylselenate, tri-p-tolylselenate, tri-o-tolylselenate, tris(4-methoxyphenyl)selenate, 1-naphthyldiphenylselenate, and other triaryl selenium salts; diphenylbenzylselenate, diphenylbenzylselenate, diphenylmethylselenate, and other diaryl selenium salts; monoaryl selenium salts such as phenylmethylbenzylselenate; and trialkylselenates such as dimethylbenzylselenate.

[0122] Examples of the aforementioned ammonium salts include: tetramethylammonium salt, ethyltrimethylammonium salt, diethyldimethylammonium salt, triethylmethylammonium salt, tetraethylammonium salt, trimethyl-n-propylammonium salt, trimethyl-n-butylammonium salt, and other tetraalkylammonium salts; pyrrolidone onium salts such as N,N-dimethylpyrrolidone onium salt and N-ethyl-N-methylpyrrolidone onium salt; imidazoline onium salts such as N,N'-dimethylimidazoline onium salt and N,N'-diethylimidazoline onium salt; and N,N'-dimethyltetrahydropyrimidine onium salt and N,N'-diethyltetrahydropyrimidine onium salt. Tetrahydropyrimidine onion salts, such as pyrimidine onion salts; N,N-dimethylpyridine onion salts, N,N-diethylpyridine onion salts, and other pyridine onion salts; N,N-dimethylpiperidine onion salts, N,N-diethylpiperidine onion salts, and other piperidine onion salts; N-methylpyridine onion salts, N-ethylpyridine onion salts, and other pyridine onion salts; N,N'-dimethylimidazolium onion salts, and other imidazolium onion salts; N-methylquinoline onion salts, and other quinoline onion salts; N-methylisoquinoline onion salts, and other isoquinoline onion salts; benzylbenzothiazolium onion salts, and other thiazolium onion salts; benzyl acridine onion salts, and other acridine onion salts, etc.

[0123] Examples of the aforementioned phosphonium salts include tetraphenylphosphonium salts, tetra-p-tolylphosphonium salts, tetra(2-methoxyphenyl)phosphonium salts, and other tetraarylphosphonium salts; triphenylbenzylphosphonium salts, and other triarylphosphonium salts; and tetraalkylphosphonium salts such as triethylbenzylphosphonium salts, tributylbenzylphosphonium salts, tetraethylphosphonium salts, tetrabutylphosphonium salts, and triethylbenzomethylphosphonium salts.

[0124] Examples of salts of the aforementioned transition metal complex ions include: salts of chromium complex cations such as (η5-cyclopentadienyl)(η6-toluene)Cr+ and (η5-cyclopentadienyl)(η6-xylene)Cr+; and salts of iron complex cations such as (η5-cyclopentadienyl)(η6-toluene)Fe+ and (η5-cyclopentadienyl)(η6-xylene)Fe+.

[0125] Examples of anions that constitute the above salts include: PF6-, BF4-, (C6F5)4B-, (C6F5)4Ga-, sulfonate anions (trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, methanesulfonate anion, benzenesulfonate anion, p-toluenesulfonate anion, etc.), perhalate anions, halosulfonate anions, sulfate anions, carbonate anions, aluminate anions, carboxylate anions, arylborate anions, thiocyanate anions, nitrate anions, etc.

[0126] Examples of initiators for the aforementioned thermo-cationic polymerization include: aryl strontium salts, aryl styrene salts, aromatic hydrocarbon-ion complexes, quaternary ammonium salts, aluminum chelates, and boron trifluoride amine complexes. Furthermore, examples of anions constituting the aforementioned salts include those identical to the anions in photo-cationic polymerization initiators.

[0127] Examples of the aforementioned aryl strontium salts include pentafluorophenyl borate and hexafluorophosphate. In the curing composition of the present invention, commercially available products such as "SP-66" and "SP-77" (manufactured by ADEKA Co., Ltd.), "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", and "SAN-AID SI-B2A" (manufactured by Sanshin Chemical Industry Co., Ltd.) can be used. Examples of the aforementioned aluminum chelates include ethyl aluminum acetate diisopropyl ester and tris(ethyl) aluminum acetate. Examples of the aforementioned boron trifluoride amine complexes include boron trifluoride monoethylamine complexes, boron trifluoride imidazole complexes, and boron trifluoride piperidine complexes.

[0128] The aforementioned free radical polymerization initiators are compounds that generate free radicals through heat or active energy line irradiation, thereby initiating the hardening reaction of the hardening compound.

[0129] Examples of free radical polymerization initiators include photoradical polymerization initiators and thermal free radical polymerization initiators. Examples of photoradical polymerization initiators include: alkyl phenyl ketone-based photoradical polymerization initiators, acetylsphin oxide-based photoradical polymerization initiators, oxime ester-based photoradical polymerization initiators, and α-hydroxyketone-based photoradical polymerization initiators.

[0130] Examples of alkyl benzophenone-based photoradical polymerization initiators include 2-hydroxy-2-methyl-1-phenylpropane-1-one, 2-benzyl-2-dimethylamino-1-(4-hydroxylinylphenyl)-1-butanone, 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-[4-(4-hydroxylinyl)phenyl]-1-butanone, 2-methyl-1-[4-(methylthio)phenyl]-2-hydroxylinylpropane-1-one, benzophenone, methylbenzophenone, o-benzoylbenzoic acid, benzoyl ethyl ether, 2,2-diethoxyacetophenone, and 2,4-diethyl-9-oxothiophene. Oligomers of diphenyl-(2,4,6-trimethylbenzoyl)phosphine oxide, ethyl-(2,4,6-trimethylbenzoyl)phenyl hypophosphite, 4,4'-bis(diethylamino)benzophenone, 1-hydroxycyclohexylphenyl ketone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propane-1-one, and 2-hydroxy-1-(4-isopropenylphenyl)-2-methylpropane-1-one, etc.

[0131] Examples of phosphine oxide photoradical polymerization initiators include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0132] Examples of photoradical polymerization initiators for the aforementioned oxime esters include 1-[4-(phenylthio)phenyl]-1,2-octanedione 2-(O-benzoyl oxime) and 1-[6-(2-methylbenzoyl)-9-ethyl-9H-carbazole-3-yl]acetone O-acetylgoxime.

[0133] Examples of α-hydroxy ketone photoradical polymerization initiators include: benzoin, benzoin methyl ether, benzoin butyl ether, 1-hydroxycyclohexylphenyl ketone, 1-phenyl-2-hydroxy-2-methylpropane-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-one, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl) ketone, and 1-hydroxycyclohexylphenyl ketone.

[0134] The content (admixture amount) of the curing catalyst in the aforementioned curing composition is not particularly limited, but is preferably 0.01 to 10 parts by mass relative to 100 parts by mass of the total amount of the curing compound, more preferably 0.03 to 5 parts by mass, and even more preferably 0.05 to 3 parts by mass. When the content of the curing catalyst is 0.01 parts by mass or more, the curing reaction tends to proceed efficiently and sufficiently, and the surface hardness of the hard coating is further improved. On the other hand, when the content of the curing catalyst is 10 parts by mass or less, the retention of the curing composition tends to be improved, and the coloring of the cured product tends to be suppressed.

[0135] The content (admixture amount) of the aforementioned cationic polymerization initiator in the curing composition is not particularly limited, but is preferably 0.005 to 10 parts by mass relative to 100 parts by mass of the total amount of the curing compound, more preferably 0.01 to 5 parts by mass, further preferably 0.015 to 3 parts by mass, and even more preferably 0.02 to 2 parts by mass. When the above content is 0.005 parts by mass or more, the curing reaction tends to proceed efficiently and sufficiently, and the surface hardness of the cured product is further improved. When the above content is 10 parts by mass or less, the retention of the curing composition tends to be improved, and the coloring of the cured product tends to be suppressed.

[0136] The content (admixture amount) of the free radical polymerization initiator in the aforementioned curing composition is not particularly limited, but is preferably 0.01 to 5 parts by mass relative to 100 parts by mass of the total curing compound, more preferably 0.03 to 3 parts by mass, and even more preferably 0.05 to 2 parts by mass. When the above content is 0.01 parts by mass or more, the curing reaction tends to proceed efficiently and sufficiently, and the surface hardness of the cured product is further improved. When the above content is 5 parts by mass or less, the retention of the curing composition tends to be improved, and the coloring of the cured product tends to be suppressed.

[0137] The aforementioned curing component preferably contains a free radical curable polyorganosiloxane as a leveling agent. By using the aforementioned free radical curable polyorganosiloxane, the smoothness of the hard coating surface is improved, and simultaneously, flexibility and flexural durability are achieved. Furthermore, the aforementioned free radical curable polyorganosiloxane is preferably not a PFAS. In this case, although it is not a PFAS, the aforementioned effects can still be achieved. Only one type of the aforementioned free radical curable polyorganosiloxane may be used, or two or more types may be used.

[0138] The aforementioned radical-curing polyorganosiloxanes possess intramolecular radical polymerizable functional groups. Examples of such radical-curing functional groups include photoradical polymerizable functional groups.

[0139] Examples of photoradical polymerizable functional groups include (meth)acrylyl, (meth)acrylamide, vinyl, and vinyl thioyl. Among these, (meth)acrylyl is preferred.

[0140] From the viewpoint that the above-mentioned free radical curable polyorganosiloxanes are preferably linear polyorganosiloxanes, which are preferred as leveling agents.

[0141] The content of the above-mentioned free radical curable polyorganosiloxane is not particularly limited, but is preferably 0.01 to 5 parts by mass relative to 100 parts by mass of the above-mentioned polyorganosiloxane, more preferably 0.03 to 3 parts by mass, and even more preferably 0.05 to 2 parts by mass.

[0142] The aforementioned curing component preferably contains an antioxidant. By including an antioxidant in the aforementioned curing component, the durability of the hard coating tends to be further improved. Only one type of antioxidant may be used, or two or more types may be used.

[0143] As an antioxidant, any well-known or commonly used antioxidant can be used without particular limitation. Examples include phenolic antioxidants, hindered amine antioxidants, phosphorus antioxidants, and sulfur antioxidants.

[0144] Examples of phenolic antioxidants include monophenols such as 2,6-di-tertiary butyl-p-cresol, butylated hydroxymethoxybenzene, 2,6-di-tertiary butyl-p-ethylphenol, and stearate β-(3,5-di-tertiary butyl-4-hydroxyphenyl)propionate; 2,2'-methylenebis(4-methyl-6-tertiary butylphenol), 2,2'-methylenebis(4-ethyl-6-tertiary butylphenol), 4,4'-thiobis(3-methyl-6-tertiary butylphenol), 4,4'-butylenebis(3-methyl-6-tertiary butylphenol), and 3,9-bis[1,1-dimethyl-2-{β-(3-tertiary butyl-4-hydroxy-5-methylphenyl)propoxy} Bisphenols such as ethyl[2,4,8,10-tetraoxaspiro[5.5]undecane; 1,1,3-trimethyl-2-methyl-4-hydroxy-5-tert-butylphenyl)butane, 1,3,5-trimethyl-2,4,6-trimethyl-3,5-di-tert-butyl-4-hydroxybenzyl)benzene, tetramethyl[3-(3',5'-di-tert-butyl-4'-hydroxyphenyl)propionate methane]methane, bis[3,3'-bis-(4'-hydroxy-3'-tert-butylphenyl)butyrate]diol ester, 1,3,5-trimethyl-3',5-di-tert-butyl-4'-hydroxybenzyl)symmetric tris(2,4,6-(1H,3H,5H)trione, tocopherol, and other high molecular weight phenols.

[0145] Examples of hindered amine antioxidants include, for example, bis(1,2,2,6,6-pentamethyl-4-piperidinyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl] butyl malonate, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, methyl-1,2,2,6,6-pentamethyl-4-sebacate piperidinyl ester, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, etc.

[0146] Examples of phosphorus-based antioxidants include: triphenyl phosphite, diphenyl isodecanyl phosphite, phenyl diisodecyl phosphite, nonylphenyl phosphite, pentaerythritol diisodecyl phosphite, 2,4-di-tertiary butylphenyl phosphite, cyclic neopentanetetrayl bis(octadecyl) phosphite, cyclic neopentanetetrayl bis(2,4-di-tertiary butylphenyl) phosphite, and cyclic neopentanetetrayl bis(2,4-di-tertiary butylphenyl) phosphite. Phosphites such as tri-butyl-4-methylphenyl phosphite and bis[2-tri-butyl-6-methyl-4-{2-(octadecyloxycarbonyl)ethyl}phenyl]hydrogen phosphite; oxaphosphaphenanthrene oxides such as 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and 10-(3,5-di-tri-butyl-4-hydroxybenzyl)-9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0147] Examples of sulfur-based antioxidants include: dodecyl mercaptan, dilaurate 3,3'-thiodipropionate, dimyristyl 3,3'-thiodipropionate, and distearate 3,3'-thiodipropionate.

[0148] When the aforementioned curing component contains an antioxidant, the content ratio of the antioxidant is not particularly limited, but is preferably 0.05 to 5 parts by mass relative to the total amount of the curing compound (100 parts by mass), and more preferably 0.1 to 1 part by mass. When the antioxidant content is 0.05 parts by mass or more, sufficient stability can be achieved. Furthermore, when the antioxidant content is 5 parts by mass or less, the coloring of the hard coating can be suppressed.

[0149] When the aforementioned curing component contains an antioxidant, its content is not particularly limited, but it is preferably 0.05 to 5 parts by weight, and more preferably 0.1 to 3 parts by weight, relative to 100 parts by weight of the polyorganosilicone sesquioxane. When the antioxidant content is 0.05 parts by weight or more, sufficient stability can be achieved. Furthermore, when the antioxidant content is 5 parts by weight or less, the coloring of the hard coating can be suppressed.

[0150] The aforementioned curable composition may further contain a solvent. There are no particular limitations as long as the solvent is capable of dissolving the aforementioned polyorganosilicone silsesquioxane and, as needed, additives, and does not hinder polymerization. Only one solvent may be used, or two or more may be used.

[0151] The solvents mentioned above are preferably solvents that can impart fluidity suitable for coating to a hard coating layer and can be easily removed by heating to a temperature that can inhibit the polymerization process. It is more preferably solvents with a boiling point (at 1 atmosphere) of 170°C or below (e.g., aromatic solvents such as toluene, xylene, and 1,3,5-trimethylbenzene; 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).

[0152] Regarding excellent coatability, the solvent is preferably used in a concentration of non-volatile components in the curing composition that is, for example, preferably 5-100% by mass, more preferably 10-80% by mass, and even more preferably 20-70% by mass. However, the amount added is not limited to the above range, and the optimal amount should be selected to adjust the viscosity to achieve an appropriate film thickness. That is, when the amount of solvent used is excessive, the viscosity of the curing composition tends to decrease, making it difficult to form a coating film of appropriate thickness. On the other hand, when the amount of solvent used is insufficient, the viscosity of the curing composition tends to be too high, making it difficult to coat the substrate uniformly.

[0153] As other components, the aforementioned curing composition may further include: inorganic fillers such as precipitated silica, wet silica, fuming silica, calcined silica, titanium dioxide, alumina, glass, quartz, aluminosilicate, iron oxide, zinc oxide, calcium carbonate, carbon black, silicon carbide, silicon nitride, and boron nitride; inorganic fillers prepared by treating such fillers with organohalosilanes, organoalkoxysilanes, organosilazanes, or other organosilane compounds; fine powders of organic resins such as polyoxyethylene resin, epoxy resin, and fluororesin; fillers, curing aids, stabilizers (light stabilizers, heat stabilizers, heavy metal deactivators, etc.) and ultraviolet absorbers (triazine-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers) of conductive metal powders such as silver and copper. Benzophenone-based UV absorbers, oxybenzophenone-based UV absorbers, salicylate-based UV absorbers, cyanoacrylate-based UV absorbers, flame retardants (phosphorus-based flame retardants, halogen-based flame retardants, inorganic flame retardants, etc.), flame retardant additives, reinforcing materials (other fillers, etc.), nucleating agents, coupling agents (silane coupling agents, etc.), lubricants, waxes, plasticizers, mold release agents, impact modifiers, color modifiers, transparent agents, rheology modifiers (flow modifiers, etc.), processability modifiers, colorants (dyes, pigments, etc.), antistatic agents, dispersants, surface modifiers (slip agents, etc.), matting agents, defoamers, foam inhibitors, defoaming agents, antibacterial agents, preservatives, viscosity modifiers, tackifiers, photosensitizers, foaming agents, and other commonly used additives. Only one of the above-mentioned components may be used, or two or more may be used. The content of the other components mentioned above is not particularly limited, but is preferably less than 100 parts by mass relative to the total amount of the curing compound, more preferably less than 30 parts by mass (e.g., 0.01 to 30 parts by mass), and even more preferably less than 10 parts by mass (e.g., 0.1 to 10 parts by mass).

[0154] Furthermore, the aforementioned curing components do not contain compounds that are PFAS. By having the above-mentioned composition, it is possible to produce a substance that does not use PFAS and complies with PFAS restrictions.

[0155] The aforementioned curing composition is not particularly limited and can be prepared by heating and stirring the components at room temperature or as needed. Furthermore, the aforementioned curing composition can be used as a liquid composition in which the components are premixed for direct use, or as a multi-liquid composition (e.g., a two-liquid composition) in which two or more components stored separately are mixed in a specific ratio before use.

[0156] The aforementioned curing composition is not particularly limited, but it is preferably a liquid at room temperature (approximately 25°C). More specifically, regarding the aforementioned curing composition, the viscosity at 25°C as a liquid diluted to 20% solvent [especially a curing composition solution with a methyl isobutyl ketone ratio of 20% by mass] is preferably 300~20000 mPa·s, more preferably 500~10000 mPa·s, and even more preferably 1000~8000 mPa·s. By achieving a viscosity of 300 mPa·s or higher, there is a tendency to further improve the curing effect (coating film). On the other hand, by achieving a viscosity of 20000 mPa·s or lower, it becomes easier to prepare or process the curing composition, and there is a tendency for air bubbles to be less likely to remain in the curing effect (coating film). Furthermore, the viscosity of the aforementioned hardening components was measured using a viscometer (trade name "MCR301", manufactured by Anton Paar) under the following conditions: oscillation angle of 5%, frequency of 0.1~100 (1 / s), and temperature of 25°C.

[0157] As a method for manufacturing the aforementioned hard coating, it can be manufactured according to well-known or conventional methods for manufacturing hard coatings. The manufacturing method is not particularly limited. For example, it can be manufactured by coating at least one surface of the substrate with the aforementioned curable composition, removing the solvent by drying as needed, and then curing the aforementioned curable composition (curable composition layer). The coating method of the curable composition or the conditions for curing are not particularly limited; for example, the following conditions may be appropriately selected.

[0158] As for the coating and curing methods of the aforementioned hard coating, general coating methods can be used. For example, well-known methods such as dip coating, roller coating, gravure coating, reverse coating, air knife coating, comma coating, mold coating, screen printing, spraying, gravure offset coating, and organic vapor deposition can be used. As for curing methods, examples include irradiation with mercury lamps, xenon lamps, carbon arc lamps, metal halide lamps, sunlight, electron beam sources, laser sources, and LED sources. Furthermore, when irradiating the aforementioned hard coating with ultraviolet light, it is preferable to have a cumulative irradiation dose of approximately 1 to 5000 mJ / cm².

[0159] There are no particular limitations on the specific hardening conditions. For example, hardening can be carried out as follows: First, the above-mentioned hardening components are subjected to heat treatment (pre-baking) at a temperature preferably above 60°C, more preferably above 120°C, and even more preferably above 150°C, for at least 10 seconds, more preferably at least 30 seconds, and even more preferably at least 60 seconds. Then, they are irradiated with ultraviolet light (irradiation conditions (irradiation dose): preferably above 300 mJ / cm2; irradiation intensity: above 100 mW / cm2). Finally, they are hardened by heat treatment (aging) at a temperature preferably above 120°C, and preferably at least 0.5 hours. However, the hardening conditions are not limited to this range. The pre-baking temperature, time, and aging temperature and time can be appropriately selected according to the solvent used. Furthermore, the ultraviolet irradiation conditions can also be appropriately selected according to the hardener used.

[0160] As described above, the aforementioned hardening components, through coating and hardening, can form a hard coating with high surface hardness and toughness. The laminate containing the hard coating produced in this manner exhibits excellent flexibility and flexural durability, and simultaneously enhances the surface hardness of the hard coating.

[0161] To further improve the recoatability of the aforementioned hard coating, surface treatments such as corona discharge treatment, plasma discharge treatment, ozone exposure treatment, and excimer laser treatment can be applied to the surface of the hard coating to modify its surface through corona discharge irradiation. Among these, corona discharge treatment is preferred in terms of easily improving recoatability.

[0162] Corona discharge treatment is a process that hardens coating surfaces by generating a continuous discharge through a non-uniform electric field around a sharp electrode (needle electrode). Plasma discharge treatment is a process that hardens coating surfaces by generating activated positive and negative charged particles through discharge in the atmosphere. Ozone exposure treatment is a process that hardens coating surfaces by generating ozone through ultraviolet irradiation using a low-pressure mercury lamp, for example, in the presence of oxygen. Excimer laser treatment is a process that hardens coating surfaces in a vacuum state by using ultraviolet irradiation or laser irradiation with an excimer lamp.

[0163] The haze of the aforementioned hard coating is preferably below 1%, more preferably below 0.7%, and even more preferably below 0.5%. Furthermore, the lower limit of haze is, for example, 0.1%. By achieving a haze of below 1%, it tends to be suitable for applications requiring high transparency.

[0164] The thickness of the aforementioned hard coating is preferably 5 to 100 μm, more preferably 10 to 70 μm. A thickness of 5 μm or more allows for sufficient surface hardness. Furthermore, a thickness of 100 μm or less facilitates flexibility. When the aforementioned hard coating is formed on both sides of the substrate, it is preferable that at least one hard coating has a thickness of 5 μm or more, more preferably 10 μm or more. Also, from the viewpoint of achieving flexibility, it is preferable that the thicknesses of the two hard coatings are each 60 μm or less, more preferably 50 μm or less.

[0165] [Image display device] As one embodiment of the present invention, an image display device having the above-described laminate can be cited as an example. In the image display device, the laminate is configured, for example, to form the viewing surface of the hard coating layer. The image display device is not particularly limited, and examples include organic light-emitting diode (OLED) display devices, inorganic light-emitting diode (INED) display devices, liquid crystal display devices, and the like. Because the surface of the hard coating layer in the above-described display device has sufficient surface hardness, the surface is not easily damaged, resulting in excellent touchability. Furthermore, because the above-described image display device has excellent flexibility and bending durability, it can also be used as a rollable or foldable display. Moreover, because it has sufficient surface hardness, flexibility, and bending durability, it can also be suitably used as a foldable device including the above-described image display device.

[0166] The various configurations disclosed in this specification can be combined with any other features disclosed in this specification. Furthermore, the various components and combinations thereof in each embodiment are examples, and appropriate additions, omissions, and other modifications to the configuration can be made without departing from the spirit of the invention. This invention is not limited to the embodiments, but only to the scope of the claims. [Example]

[0167] The following describes one embodiment of the present invention in more detail based on examples.

[0168] Manufacturing Example 1 (Manufacturing of polyorganosilicon silsesquioxanes) 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 added to a 1000 mL flask (reaction vessel) equipped with a thermometer, stirrer, reflux condenser, and nitrogen inlet tube under a nitrogen atmosphere, and the mixture was heated to 50°C. 7.74 g of a 5% potassium carbonate aqueous solution (2.8 mmol based on potassium carbonate) was added to the mixture over 5 minutes, followed by the addition of 2800.0 mmol (50.40 g) of water over 20 minutes. No significant temperature rise occurred during the addition. The polymerization reaction was then carried out at 50°C under a nitrogen atmosphere for 5 hours. Subsequently, the reaction solution was cooled, and 137.70 g of methyl isobutyl ketone and 100.60 g of 5% saline solution were added simultaneously. The solution was transferred to a 1 L separatory funnel, and another 137.70 g of methyl isobutyl ketone was added, followed by washing with water. After separation, the aqueous layer was removed and washed with water until the lower layer became neutral. The upper layer was then separated, and the solvent was removed by distillation at 1 mmHg and 50°C to obtain 75.18 g of a colorless, transparent, liquid product (a low molecular weight polyorganosilsesquioxane containing epoxy groups: the silsesquioxane of Manufacturing Example 1) containing 23% by mass of methyl isobutyl ketone. Furthermore, the analysis of the product showed a number average molecular weight of 2235 and a molecular weight dispersion of 1.54. The ratio of T2 to T3 phases [T3 / T2] calculated from the 29Si-NMR spectrum of the product was 11.9. This was confirmed by 1H-NMR and 29Si-NMR of the obtained epoxy-containing low molecular weight polyorganosilsesquioxane. Furthermore, the molecular weight of the product was determined using the following method: pump: Shimadzu LC-20AD; detector: Shodex RI-504; column: Shodex GPC KF-602, KF-603; guard column: Shodex GPC KF-G; solvent: THF; measurement conditions: 40℃. Also, the ratio of T2 to T3 components in the product [T3 / T2] was determined using 29Si-NMR spectroscopy on a JEOL ECA500 (500 MHz) spectrometer.

[0169] (Preparation of hard coating agent) The materials were mixed with the aforementioned silsesquioxane to achieve the composition ratios shown in Table 1, and the hard coatings of the Examples and Comparative Examples were prepared. Furthermore, the proportions shown in the table are the blending ratios of each component. For the silsesquioxane (77% by mass of active ingredient) and RS-57 (20% by mass of active ingredient) in Example 1, these are values ​​for the solution; for the other components, these are values ​​for the active ingredient.

[0170] ◎[Table 1] Table 1 Material Name Example Comparative example Composition ratio (parts by mass) Composition ratio (parts by mass) hardening compounds Manufacturing Example 1: Silsesquioxane 66.8 66.8 200PA-E5 1.5 1.5 EPOLIGHT 1600N 6.2 6.2 free radical polymerization initiators Omnirad 127 0.2 0.2 cationic polymerization initiator Salts of triarylstrom and tetrapentafluorophenyl gallium 0.5 0.5 antioxidants ADK STAB AO-20 0.12 0.12 Leveling agent KY1203 - 0.4 RS-57 0.4 - solvent MIBK 8.4 8.4 MEK 15.8 15.8

[0171] The components used in Table 1 are described in detail below. 200PA-E5: Trade name "EPOXYESTER 200PA-E5", manufactured by Kyoei Chemical Co., Ltd. (a compound having one or more cationic polymerizable groups and one or more free radical polymerizable groups within the molecule). EPOLIGHT 1600N: Trade name "EPOLIGHT 1600N", manufactured by Kyoei Chemical Co., Ltd. (an aliphatic compound having two or more cationic polymerizable groups within its molecule). Omnirad 127: Trade name "Omnirad 127", manufactured by IGM Resins BV (free radical polymerization initiator). Salts of triarylstrom and tetra-pentafluorophenyl gallium: photocationic polymerization initiators ADK STAB AO-02: Trade name "ADK STAB AO-02", manufactured by ADEKA Corporation (antioxidant). KY1203: Trade name "KY1203", contains compounds belonging to PFAS, manufactured by Shin-Etsu Chemical Co., Ltd. (leveling agent). RS-57: Trade name "RS-57", a polysiloxane resin that does not contain PFAS compounds, manufactured by DIC Corporation (leveling agent). MIBK: Methyl isobutyl ketone (solvent) MEK: Methyl ethyl ketone (solvent)

[0172] Examples 1 and 2 The hardening agent described in the above embodiments was applied to a PET substrate (trade name "TA069", manufactured by TOYOBO Co., Ltd.) using No. 12 and No. 22 wire rods to achieve hardened thicknesses of 10 μm and 20 μm, respectively. The substrate was then placed in an oven at 80°C for 1 minute and in an oven at 120°C for 2 minutes. Subsequently, the substrate was irradiated with ultraviolet light using a high-pressure mercury lamp at an illuminance of 300 mJ / cm² to form a hard coating. Afterward, the substrate was placed in an oven at 120°C for 60 minutes to produce the laminates of Examples 1 and 2.

[0173] Comparative Examples 1 and 2 The hard coating agent of the above comparative examples was applied to a PET substrate (trade name "TA069", manufactured by TOYOBO Co., Ltd.) using No. 12 and No. 22 wire rods respectively, so that the hard coating agent after hardening was 10 μm and 20 μm respectively. Otherwise, the laminates of comparative examples 1 and 2 were made in the same way as the laminates of examples 1 and 2.

[0174] [evaluate] The laminates produced in the examples and comparative examples were evaluated as follows, and the results are recorded in Table 2.

[0175] (1) Haze For the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, the haze value (%) was measured using a haze measuring device (trade name "NDH-5000W", manufactured by Nippon Denshoku Kogyo Co., Ltd.). This measurement was performed in accordance with JIS K7136.

[0176] (2) Total light transmittance 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 measuring device (trade name "NDH-5000W", manufactured by Nippon Denshoku Kogyo Co., Ltd.). This measurement was performed in accordance with JIS K7105.

[0177] (3) Pencil hardness For the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, the pencil hardness of the hard coating surface was evaluated according to JIS K5600-5-4 (750 g load).

[0178] (4) Wear resistance For the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, the surface of the hard coating was subjected to 1000 cycles of #0000 steel wool with a load of 750 g / cm2 to check for any damage to the surface of the hard coating.

[0179] (5) Flexibility For the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, a cylindrical mandrel bending tester (trade name "Bending Tester (Cylindrical Mandrel Method)" manufactured by TP Tech Co., Ltd.) was used to determine the bending properties when the hard coating was set as the inner side and when it was set as the outer side, according to the cylindrical mandrel method of JIS K5600-5-1 (1999).

[0180] (6) Continuous bending durability For the laminates of Examples 1 and 2 and Comparative Examples 1 and 2, continuous bending durability tests were performed using a planar unloaded U-shaped stretch tester (trade name "Z-044", manufactured by YUASA SYSTEM Machinery Co., Ltd.). The test involved bending the hard coating surface with the convex side at a radius of 4.0 mm 180° and then flattening it again, which was defined as one cycle. This was performed 10,000 times at a speed of 30-60 cycles / minute to check for cracks in the hard coating and the PET substrate.

[0181] [Table 2] Table 2 Comparative Example 1 Comparative Example 2 Example 1 Example 2 Optical properties Film thickness (μm) 10 20 10 20 Haze (%) 0.4 0.5 0.4 0.5 Total light transmittance (%) 91.4 91.3 91.6 91.4 Pencil hardness 750 g load H 3H H 3H Abrasion resistance After a 750 g load and 1000 round trips No damage No damage No damage No damage Bending Hard coating inside 2 mmϕ 2 mmϕ 2 mmϕ 2 mmϕ hard coating outer side 3 mmϕ 4 mmϕ 4 mmϕ 4 mmϕ Flexural durability hard coating outer side No cracks No cracks No cracks No cracks

[0182] It was confirmed that, compared with the laminates of the comparative example that used compounds belonging to PFAS, the laminates of the examples exhibited the same hardness and flexibility, and achieved sufficient wear resistance and flexibility without the use of fluorine compounds.

[0183] The following describes variations of the invention disclosed herein. [Postscript 1] A laminate comprising a substrate and a hard coating layer deposited on at least one side of the substrate, and The aforementioned hard coating does not contain any laminates of compounds belonging to PFAS; and In a test of a cylindrical mandrel in which the surface of the hard coating of the above-mentioned laminate is bent in a way that makes it convex, the minimum bending radius is 5 mm or less. [Postscript 2] As described in Appendix 1, the hard coating undergoes more than 10,000 cycles in the following bending durability test until cracks appear in the hard coating. Bending durability test: One repetition is defined as bending the laminate from its flattened state toward the surface of the hard coating at a bending radius of 4.0 mm by 180° and then flattening it again. This repetition is performed at a speed of 30 to 60 times per minute. [Postscript 3] As described in Appendix 1 or 2, the hard coating material, in a steel wool resistance test in which a load of 750 g / cm2 is applied using #0000 steel wool and the surface of the hard coating material is rubbed back and forth 1000 times, shows no visible damage. [Postscript 4] As described in any of Notes 1 to 3, the haze of the aforementioned hard coating is less than 1.0%. [Postscript 5] For example, the haze of the laminar bodies described in any of Notes 1 to 4 is less than 7%. [Postscript 6] As described in any of Appendix 1 to 5, the aforementioned hard coating is a hardened material comprising a hardening composition of one or more hardening compounds, and includes a polyorganosilsesquioxane as the aforementioned hardening compound. [Postscript 7] As described in Appendix 6, the laminate contains a compound having one or more cationic polymeric groups and one or more free radical polymeric groups within its molecule. [Postscript 8] As described in Appendix 6 or 7, the laminated body further comprises a hardening catalyst. [Postscript 9] As described in Appendix 8, the laminate contains a cationic polymerization initiator. [Postscript 10] As described in Appendix 8 or 9, the laminated body, wherein the aforementioned hardening catalyst contains a free radical polymerization initiator. [Postscript 11] As described in any of Appendix 6 to 10, the laminate further comprises a free radical curing polyorganosiloxane polysiloxane resin. [Postscript 12] As described in any of Appendix 6 to 11, the aforementioned curing component further comprises an aliphatic compound having two or more cationic polymeric groups within its molecule. [Postscript 13] As described in any of Notes 1 to 12, the substrate is a transparent substrate. [Postscript 14] As described in any of Notes 1 to 13, the laminate has a surface protective film on at least one surface. [Postscript 15] The laminate described in any of Appendix 1 to 14 has the hard coating on one side of the substrate and an adhesive layer on the other side. [Postscript 16] An image display device having a laminate as described in any one of Appendix 1 to 15. [Postscript 17] The image display device described in Appendix 16 is a foldable display. [Postscript 18] The image display device described in Appendix 16 or 17 is an organic electroluminescent display device. [Postscript 19] A foldable device comprising the image display device described in any one of Appendices 16 to 18.

Claims

1. A laminate having a substrate and a hard coating layer laminated on at least one side of the substrate, wherein the hard coating layer is free of compounds belonging to PFAS (per- and polyfluoroalkyl substances), wherein the hard coating layer is a hardened material comprising a hardening composition containing one or more hardening compounds, wherein the hardening composition comprises an aliphatic compound having two or more cationic polymeric groups within its molecule; and in a test of a cylindrical mandrel in which the surface of the hard coating layer of the laminate is bent in a convex manner, the minimum bending radius is 5 mm or less.

2. As in request item 1, the stacked volume, wherein, In the following bending durability test, the hard coating is subjected to more than 10,000 cycles until cracks appear in the hard coating. Bending durability test: The stack is bent 180° from its flattened state toward the surface of the hard coating with a bending radius of 4.0 mm and then flattened again. This action is defined as 1 cycle. The above action is performed at a speed of 30 to 60 cycles / minute.

3. As in request item 1 or 2, the stacked volume, wherein, The aforementioned hard coating showed no visible damage in a steel wool resistance test, in which a load of 750 g / cm2 was applied using #0000 steel wool while the surface of the hard coating was rubbed back and forth 1000 times.

4. As in request item 1 or 2, wherein, The haze of the above-mentioned hard coating is less than 1.0%.

5. For the laminates requested in item 1 or 2, the haze is less than 7%.

6. As in request item 1 or 2, the stacked volume, wherein, The aforementioned hard coating contains a polyorganosilyl sesquioxane as the aforementioned curing compound.

7. As in request item 6, the stacked volume, wherein, The aforementioned hardening components comprise compounds having one or more cationic polymeric groups and one or more free radical polymeric groups within their molecules.

8. As in request item 6, the stacked volume, wherein, The aforementioned hardening components further include a hardening catalyst.

9. As in request item 8, the layered body, wherein, The aforementioned hardening catalyst contains a cationic polymerization initiator.

10. As in request item 8, the stacked volume, wherein, The aforementioned hardening catalyst contains a free radical polymerization initiator.

11. As in request item 6, the stacked volume, wherein, The aforementioned curing components further include free radical curing polyorganosiloxanes.

12. As in request item 1 or 2, the stacked volume, wherein, The aforementioned substrate is a transparent substrate.

13. The laminate of claim 1 or 2, having a surface protective film on at least one surface.

14. The laminate of claim 1 or 2, having the hard coating on one side of the substrate and an adhesive layer on the other side.

15. An image display device having a laminate of claim 1 or 2.

16. The image display device of claim 15 is a foldable display.

17. The image display device of claim 15 is an organic electroluminescent display device.

18. A foldable device comprising the image display device of claim 15.