Curable composition for forming hard coat layer

Abstract

Provided is a curable composition for forming a hard coat layer, which has excellent wear resistance, excellent sliding properties, and excellent elastic modulus. The curable composition for forming a hard coat layer contains (a) a polyfunctional (meth) acrylate monomer, (b) a surface modifier, (c) a polymerization initiator, and (d) a conductive polymer material, wherein the content of the (d) conductive polymer material is 5.5-15 parts by mass per 100 parts by mass of the (a) polyfunctional (meth) acrylate monomer. A hard coat layer, which is a cured product of the curable composition for forming a hard coat layer, has a surface water contact angle of 90 degrees or more after a wear resistance test, a dynamic friction coefficient of 0.30 or less on the surface, a surface energy of 35 dyne / cm or less, and a surface thickness of 30 [mu] m or less. When the surface of the hard coat layer is measured by a nanoindentation method, the indentation hardness is 0.25 GPa or more and less than 0.45 GPa, and the indentation elastic modulus measured by the nanoindentation method is 3 GPa or more.

Description

Technical Field

[0001] This invention relates to curable compositions that can be used as forming materials for hard coatings applicable to the surfaces of various display devices, such as flexible displays. More specifically, it relates to curable compositions capable of forming hard coatings exhibiting excellent wear resistance, excellent slip properties, and excellent elastic modulus. Background Technology

[0002] In recent years, touch panels, which allow users to operate the display with their fingers or pens while viewing the screen, have become increasingly popular in portable information terminals such as mobile phones and tablets, home appliances such as computers and televisions, and automotive display panels. Typically, to prevent damage to the display, protective glass or plastic films with scratch-resistant hard coatings are applied to the surface of the touch panel.

[0003] Since touch panels are operated using human fingers or pens, they require stain resistance (e.g., hydrophobicity and oleophobicity) to prevent moisture from sweat and oil from sebum from adhering to the surface, as well as smooth writing performance. However, repeated contact with fingers and pens causes friction that wears down the hard coating, and even with sufficient initial stain resistance, this function often diminishes over time. Therefore, it is desirable for the hard coating to have extremely high abrasion resistance to maintain its initial stain resistance.

[0004] A common method for forming hard coatings is as follows: a hard coating liquid containing a multifunctional acrylate as a main agent, a photopolymerization initiator for curing the multifunctional acrylate through free radical polymerization based on active energy rays, and an organic solvent for diluting the acrylate to impart coatability is applied to a substrate. The organic solvent is removed by heating and drying, and then the hard coating is obtained by curing based on active energy rays. However, multifunctional acrylate materials are prone to becoming charged, which can lead to dust adhesion during operation or use.

[0005] To address this problem, a method has been proposed to impart antistatic properties to hard coatings by adding various conductive materials (Patent Document 1).

[0006] According to reports, the hard coating described in Patent Document 1 exhibits excellent antifouling properties by including a compound with fluorine-containing UV-curable functional groups, a conductive polymer, and a solvent in the hard coating layer. The surface roughness (Ra) of the hard coating, measured using AFM (Atomic Force Microscope) (measurement conditions: Non-Contact Mode, Scan Size: 1μm × 1μm, Scan Rate: 1.0Hz), is less than 1 nm. However, the mechanical properties of the single layer of the hard coating, such as the sliding properties of the hard coating expressed as the coefficient of kinetic friction and the elastic modulus of the hard coating expressed as the indentation elastic modulus, have not been sufficiently studied.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2021-056515 Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] The purpose of this invention is to provide a curable composition for forming a hard coating that has excellent wear resistance, excellent sliding properties and excellent elastic modulus.

[0012] Problem-solving methods

[0013] To achieve the above objectives, the inventors conducted repeated and in-depth research, and as a result discovered a curable composition for forming a hard coating that can form a hard coating with excellent wear resistance, excellent sliding properties, and excellent elastic modulus, thus completing the present invention. The curable composition for forming the hard coating comprises (a) a polyfunctional (meth)acrylate monomer, (b) a surface modifier, (c) a polymerization initiator, and (d) a conductive polymer material, wherein the content of the conductive polymer material is 5.5 to 15 parts by weight relative to 100 parts by weight of the polyfunctional (meth)acrylate monomer (a). For the hard coating that is the cured product of the curable composition for forming the hard coating, the water contact angle of the surface after the abrasion resistance test is 90 degrees or more, the dynamic friction coefficient of the surface of the hard coating is 0.30 or less, the surface energy of the hard coating is 35 dyne / cm or less, the indentation hardness when the surface of the hard coating is measured by nanoindentation is 0.25 GPa or more and less than 0.45 GPa, and the indentation elastic modulus measured by nanoindentation is 3 GPa or more.

[0014] The first aspect of the present invention relates to a curable composition for forming a hard coating, comprising (a) a polyfunctional (meth)acrylate monomer, (b) a surface modifier, (c) a polymerization initiator, and (d) a conductive polymer material, wherein the content of the conductive polymer material is 5.5 to 15 parts by mass relative to 100 parts by mass of the polyfunctional (meth)acrylate monomer. For the hard coating as a cured product of the curable composition for forming the hard coating, after an abrasion resistance test, the water contact angle of the surface is 90 degrees or more, the coefficient of kinetic friction of the surface of the hard coating is 0.30 or less, the surface energy of the hard coating is 35 dyne / cm or less, the indentation hardness when the surface of the hard coating is measured by nanoindentation is 0.25 GPa or more and less than 0.45 GPa, and the indentation elastic modulus measured by nanoindentation is 3 GPa or more.

[0015] The conductive polymeric materials mentioned above (d) include, for example, poly(3,4-ethylenedioxythiophene).

[0016] The conductive polymeric materials mentioned above (d) include, for example, poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonic acid.

[0017] The content of the conductive polymer material in (d) above is, for example, 5.5 to 10 parts by mass relative to 100 parts by mass of the polyfunctional (meth)acrylate monomer in (a) above.

[0018] The surface modifier described above (b) may include, for example, a perfluoropolyether, wherein the perfluoropolyether has at least two (meth)acryloyloxy groups at the end of a molecular chain containing a poly(oxyperfluoroalkylene) group as shown in the following formula [1] via urethane bonds.

[0019]

[0020] In the above formula [1], PFPE represents a poly(oxy-perfluoroalkylene) group having at least one of repeating units -(CF2CF2O)- and repeating units -(CF2O)-, and these repeating units are bonded by block bonding, random bonding, or block bonding and random bonding. This indicates the bonding site of the -O- group to the above-mentioned urethane bond.

[0021] The surface modifier described above (b) may include, for example, a perfluoropolyether, wherein the perfluoropolyether has, at the end of the molecular chain containing the poly(oxyperfluoroalkylene) group shown in Formula [1], a group shown in Formula [A1] or Formula [A2], respectively, bonded by the above-described urethane bond.

[0022]

[0023] In the above equations [A1] and [A2], R 1 and R 2 Each atom independently represents a hydrogen atom or a methyl group, and the black dots represent the bonding sites of the -NH- groups of the above-mentioned carbamate bonds.

[0024] The curable composition for forming a hard coating according to the present invention may further contain (e) a solvent.

[0025] A second aspect of the present invention is a hard coating film having a hard coating layer on at least one surface of a film substrate, the hard coating layer being a cured product of the aforementioned hard coating forming curable composition.

[0026] A third aspect of the present invention is a display device having the above-described hard coating.

[0027] Invention Effects

[0028] According to the present invention, a curable composition useful for forming a hard coating having excellent wear resistance, excellent sliding properties, and excellent elastic modulus can be provided. Furthermore, according to the present invention, a hard coating film having the hard coating obtained from the above-described curable composition applied to its surface can be provided, which can provide a hard coating film having excellent wear resistance, excellent sliding properties, and excellent elastic modulus. Additionally, according to the present invention, a display device having the above-described hard coating film can be provided, which can provide a display device having excellent wear resistance, excellent sliding properties, and excellent elastic modulus.

[0029] Specific embodiments of the invention

[0030] <Curing compositions for hard coating formation>

[0031] The curable composition for forming a hard coating of the present invention (hereinafter also simply referred to as the "curable composition") is a curable composition for forming a hard coating comprising (a) a polyfunctional (meth)acrylate monomer, (b) a surface modifier, (c) a polymerization initiator, and (d) a conductive polymer material. Furthermore, the content of the conductive polymer material (d) is 5.5 to 15 parts by weight relative to 100 parts by weight of the polyfunctional (meth)acrylate monomer (a).

[0032] [Hard coating]

[0033] As a hard coating of the cured product of the curable composition for forming a hard coating according to the present invention, the surface of the hard coating has a water contact angle of 90 degrees or more after an abrasion resistance test. The surface of the hard coating has a dynamic friction coefficient of less than 0.30. The surface energy of the hard coating is below 35 dyne / cm. When the surface of the hard coating is measured using the nanoindentation method, the indentation hardness is greater than or equal to 0.25 GPa and less than 0.45 GPa, and the indentation elastic modulus measured using the nanoindentation method is greater than or equal to 3 GPa.

[0034] The abrasion resistance test is evaluated by, for example, an eraser test in which the hard coating surface is subjected to more than 3000 reciprocating rubbing cycles with an eraser, and the water contact angle of the hard coating surface is 90 degrees or more. If the water contact angle is 90 degrees or more, the hard coating is deemed to have excellent abrasion resistance and also excellent antifouling properties. The water contact angle is preferably 95 degrees or more, and more preferably 98 degrees or more.

[0035] The eraser test was used because the friction of an eraser is similar to that of a stylus, making the eraser test a more accurate assessment of the stylus's abrasion resistance. It should be noted that the abrasion resistance of hard coatings has traditionally been evaluated by rubbing steel wool against the surface of the hard coating. However, steel wool consists of fine metal threads, which are significantly different from a stylus. Therefore, the abrasion resistance of styluses, in particular, cannot be evaluated using the steel wool test.

[0036] The above-mentioned eraser-based test involves mounting a cylindrical eraser [Minoan Rubber Stick (Φ6.0mm)] with a clamp on a reciprocating abrasion testing machine (TRIBOGEAR TYPE: 30H, manufactured by Shin-To Science & Technology Co., Ltd.). While simultaneously evaluating the chemical resistance of the hard coating, ethanol is dropped onto the hard coating surface under a load of 3.54 kg / cm². 2 The eraser was used to perform more than 3000 reciprocating rubs on the surface of the hard coating under the conditions of a scanning speed of 0.5 m / min and a single-pass scanning distance of 15 mm (reciprocating scanning distance of 30 mm). In the eraser test, an A4-sized hard coating film with a hard coating formed on the thin film substrate described later was used. Then, 3 μL of water was applied to the rubbed area after the eraser test, and the water contact angle θ was measured 5 times after 5 seconds. The average value was taken as the water contact angle value.

[0037] The coefficient of kinetic friction of the hard coating surface of the cured product of the curable composition of the present invention is 0.30 or less. The coefficient of kinetic friction is an indicator of the sliding properties of the hard coating surface. When the coefficient of kinetic friction is 0.30 or less, the sliding properties of the hard coating surface become good, and the wear resistance is also superior. The smaller the coefficient of kinetic friction, the better the sliding properties and wear resistance. More preferably, it is 0.25 or less, and even more preferably, it is 0.20 or less.

[0038] The coefficient of dynamic friction of the aforementioned hard coating is determined, for example, by the following method. That is, using a load-variable friction and wear testing system (TRIBOGEAR (registered trademark) TYPE: HHS2000 manufactured by Shin-To Science Co., Ltd., probe: 0.6mmR sapphire needle, load: 200g), after sliding twice under the conditions of scanning speed: 2mm / second and scanning distance: 10mm, the measurement value of the third sliding is obtained.

[0039] The surface energy of the hard coating of the cured product of the curable composition of the present invention is 35 dyne / cm or less. Surface energy is an indicator of stain resistance; if the surface energy is 35 dyne / cm or less, the stain resistance becomes good, and consequently, the wear resistance is also excellent. The lower the surface energy, the better the wear resistance; more preferably, it is 30 dyne / cm or less, and even more preferably, it is 25 dyne / cm or less.

[0040] The surface energy of the aforementioned hard coating is determined, for example, by the following method: using a contact angle meter (DropMaster DM-501 manufactured by Kyowa Interface Science Co., Ltd.), 3 μL of water or 1 μL of diiodomethane is applied to the surface of the hard coating, and the contact angle θ is measured five times after 5 seconds. The surface energy of the hard coating is calculated from the average contact angle of these solvents.

[0041] For the hard coating of the cured product of the curable composition of the present invention, when its surface is measured by nanoindentation, the indentation hardness is 0.25 GPa or more and less than 0.45 GPa, and the indentation elastic modulus measured by nanoindentation is 3 GPa or more. When the indentation hardness and indentation elastic modulus of the hard coating surface are within the above range, the hard coating has excellent hardness and elastic modulus. The indentation hardness is more preferably 0.30 GPa or more and 0.40 GPa or less. Furthermore, the indentation elastic modulus is more preferably 4 GPa or more.

[0042] Examples of indenters used in nanoindentation include triangular pyramid indenters (Berkovich type), square pyramid indenters (Vickers type), conical indenters, and ball indenters. Among these indenters, the triangular pyramid indenter (Berkovich type) is preferred because it allows for more precise control in areas with shallow indentation depth.

[0043] The indentation hardness and indentation modulus of the above-mentioned hard coating surface are obtained by nanoindentation, for example, by the following method: The hard coating is brought into contact with a triangular pyramid indenter (Berkovich type), and a nanoindenter (iNano nanoindenter manufactured by Toyo Technica Co., Ltd.) is used to indent the triangular pyramid indenter (Berkovich type) at 23°C with a load holding time of 1 second until the maximum indentation load of 50mN or the maximum indentation depth of 1500nm is reached. The load unloading curve (force curve) is measured, and the indentation hardness and indentation modulus of elasticity are determined based on ISO14577.

[0044] <Curing compositions for hard coating formation>

[0045] The curable composition for forming a hard coating of the present invention comprises (a) a multifunctional (meth)acrylate monomer, (b) a surface modifier, (c) a polymerization initiator and (d) a conductive polymer material.

[0046] [(a) Multifunctional (meth)acrylate monomers]

[0047] The polyfunctional (meth)acrylate monomer that can be used as component (a) of the curable composition of the present invention is a monomeric compound having two or more (meth)acryloyloxy groups per molecule. This polyfunctional (meth)acrylate monomer undergoes a polymerization reaction by irradiation with active energy rays such as ultraviolet light, thereby curing it. It should be noted that in the present invention, (meth)acrylate compounds include both acrylate compounds and methacrylate compounds; for example, (meth)acrylic acid includes acrylic acid and methacrylic acid.

[0048] Preferred polyfunctional (meth)acrylate monomers for the curable compositions of the present invention include monomers selected from polyfunctional (meth)acrylate compounds without urethane bonds, polyfunctional urethane (meth)acrylate compounds, and lactone-modified polyfunctional (meth)acrylate compounds. In the present invention, one or more of the above-mentioned polyfunctional (meth)acrylate compounds may be used alone or in combination as the (a) polyfunctional (meth)acrylate monomer.

[0049] Additionally, (a) the polyfunctional (meth)acrylate monomer can be an oxoalkylene-modified polyfunctional (meth)acrylate monomer. Examples of such oxoalkylene modification include oxomethylene modification, oxoethylene modification (also known as EO modification), and oxopropylene modification. Examples of such oxoalkylene-modified polyfunctional monomers include compounds that have undergone oxoalkylene modification in the aforementioned polyfunctional (meth)acrylate compounds or polyfunctional urethane (meth)acrylate compounds. The aforementioned oxoalkylene-modified polyfunctional monomers can also be used alone or in combination of two or more.

[0050] Furthermore, as a preferred (a) polyfunctional (meth)acrylate monomer in this invention, examples include polyfunctional (meth)acrylate monomers having at least 3 (meth)acryloyl groups per molecule, for example, having at least 4 (meth)acryloyl groups per molecule. In this invention, as a (a) polyfunctional (meth)acrylate monomer, monomers selected from oxoalkylene-modified polyfunctional (meth)acrylate compounds having at least 3 (meth)acryloyl groups per molecule can be listed.

[0051] Examples of polyfunctional (meth)acrylate compounds that do not possess urethane bonds include trimethylolpropane tri(meth)acrylate, di(trimethylolpropane)tetra(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerol tri(meth)acrylate, 1,3-propanediol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, and 1,6-hexanediol di(meth)acrylate. Acrylates, 2-methyl-1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, bis(2-hydroxyethyl) isocyanurate di(meth)acrylate, tri(2-hydroxyethyl) isocyanurate tri(meth)acrylate, tricyclic [5.2.1.0] 2,6Decanediol di(meth)acrylate, dioxanediol di(meth)acrylate, 2-hydroxy-1-acryloyloxy-3-methacryloyloxypropane, 2-hydroxy-1,3-di(meth)acryloyloxypropane, 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene, bis[4-(meth)acryloylthiophenyl]sulfide, bis[2-(meth)acryloylthioethyl]sulfide, 1,3-adamantanediol di(meth)acrylate, 1,3-adamantanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate. Among these, preferred polyfunctional (meth)acrylate compounds without urethane bonds include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

[0052] Examples of the aforementioned oxoalkylene-modified polyfunctional (meth)acrylate compounds include, for example, (meth)acrylate compounds of polyols modified with oxoalkylene. Examples of such polyols include glycerol, diglycerol, triglycerol, tetraglycerol, pentaglycerol, hexaglycerol, decaglycerol, polyglycerol, trimethylolpropane, di(trimethylolpropane), pentaerythritol, dipentaerythritol, and bisphenol A. Examples of the aforementioned oxoalkylene-modified polyol (meth)acrylate compounds include, for example, EO-modified trimethylolpropane tri(meth)acrylate, EO-modified pentaerythritol tetra(meth)acrylate, EO-modified dipentaerythritol hexa(meth)acrylate, EO-modified glycerol tri(meth)acrylate, EO-modified diglycerol (meth)acrylate, and EO-modified bisphenol A di(meth)acrylate.

[0053] The aforementioned polyfunctional urethane (meth)acrylate compounds are compounds having multiple acryloyl or methacryloyl groups per molecule and having one or more urethane bonds [-NHC(=O)O-], and may further have urea bonds [-NHC(=O)NH-]. Examples of such polyfunctional urethane (meth)acrylate compounds include, for instance, compounds obtained by reacting a polyfunctional isocyanate with a hydroxyl-containing (meth)acrylate, and compounds obtained by reacting a polyfunctional isocyanate with a hydroxyl-containing (meth)acrylate and a polyol; however, the polyfunctional urethane (meth)acrylate compounds used in this invention are not limited to these exemplary varieties.

[0054] It should be noted that examples of the aforementioned polyfunctional isocyanates include, for example, toluene diisocyanate, isophorone diisocyanate, phenylene diisocyanate, and hexamethylene diisocyanate. Additionally, examples of the aforementioned hydroxyl-containing (meth)acrylates include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and tripentaerythritol hepta(meth)acrylate. Furthermore, examples of the aforementioned polyols include, for example, diols such as ethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and dipropylene glycol; polyester polyols as reaction products of these diols with aliphatic dicarboxylic acids or dicarboxylic anhydrides such as succinic acid, maleic acid, and adipic acid; polyether polyols; and polycarbonate diols.

[0055] (a) The polyfunctional (meth)acrylate monomer can be a lactone-modified polyfunctional (meth)acrylate compound, and ε-caprolactone is preferred as the lactone to be modified. Examples of the above-mentioned lactone-modified polyfunctional (meth)acrylate compounds include, for example, ε-caprolactone-modified pentaerythritol tri(meth)acrylate, ε-caprolactone-modified pentaerythritol tetra(meth)acrylate, ε-caprolactone-modified dipentaerythritol penta(meth)acrylate, and ε-caprolactone-modified dipentaerythritol hexa(meth)acrylate.

[0056] Among the aforementioned polyfunctional (meth)acrylate monomers, particularly preferred polyfunctional (meth)acrylate monomers include pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, EO-modified pentaerythritol tetra(meth)acrylate, EO-modified dipentaerythritol hexa(meth)acrylate, and EO-modified diglycerol (meth)acrylate. By using these particularly preferred polyfunctional (meth)acrylate compounds, both superior wear resistance and superior hardness and elastic modulus can be simultaneously achieved.

[0057] [(b) Surface modifiers]

[0058] (b) There are no particular limitations on the surface modifier, but it is preferred to be a perfluoropolyether with an active energy-ray polymerizable group at the end of the molecular chain containing the poly(oxy-perfluoroalkylene) group. Hereinafter, this perfluoropolyether will also be referred to as "(b1) perfluoropolyether". The end of the molecular chain containing the poly(oxy-perfluoroalkylene) group with the active energy-ray polymerizable group can be any one of the entire end and part of the end of the molecular chain. When the molecular chain is linear, the entire end and part of the end of the molecular chain are respectively the two ends and one end of the linear molecular chain. For (b1) perfluoropolyether, it is preferred to have an active energy-ray polymerizable group at the end of the molecular chain containing the poly(oxy-perfluoroalkylene) group via a urethane bond. As such a (b1) perfluoropolyether, it is preferred to have at least two (meth)acryloyloxy groups at the end of the molecular chain containing the poly(oxy-perfluoroalkylene) group as shown in the following formula [1] via a urethane bond.

[0059]

[0060] In the above formula [1], PFPE represents a poly(oxy-perfluoroalkylene) group having at least one of repeating units -(CF2CF2O)- and repeating units -(CF2O)-, and these repeating units are bonded by block bonding, random bonding, or block bonding and random bonding. This indicates the bonding site of the -O- group to the above-mentioned urethane bond.

[0061] As for the aforementioned poly(oxyperfluoroalkylene) groups, from the perspective of obtaining a hard coating with good wear resistance and scratch resistance, groups having both -[CF2O]-(oxyperfluoromethylene) and -[CF2CF2O]-(oxyperfluoroethylene) as repeating units are preferred. In this case, the bonding of these oxyperfluoroalkyl groups can be either block bonding or random bonding.

[0062] (b1) Perfluoropolyether, more preferably a perfluoropolyether comprising the following, wherein the molecular chain containing poly(oxy-perfluoroalkylene) groups shown in the above formula [1] is bonded to the end of the molecular chain by the above urethane bond with groups shown in formula [A1] or formula [A2].

[0063]

[0064] In the above equations [A1] and [A2], R 1 and R 2 Each atom independently represents a hydrogen atom or a methyl group, and the black dots represent the bonding sites of the -NH- groups of the above-mentioned carbamate bonds.

[0065] (b1) Perfluoropolyether, from the viewpoint of obtaining a hard coating with good wear resistance and scratch resistance, is more preferably provided with active energy-emitting polymerizable groups at both ends of the molecular chain containing poly(oxy-perfluoroalkylene) groups, and even more preferably, the number of such active energy-emitting polymerizable groups per molecule is large. The number of such polymerizable groups is preferably two or more at each end of the molecular chain containing poly(oxy-perfluoroalkylene) groups, more preferably three or more.

[0066] In the curable composition of the present invention, the content of the surface modifier (b) is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, and even more preferably 0.1 to 3 parts by weight, relative to 100 parts by weight of the polyfunctional (meth)acrylate monomer (a). By making the content of the surface modifier (b) 0.05 parts by weight or more, sufficient wear resistance and sliding properties can be imparted to the hard coating. In addition, by making the content of the surface modifier (b) 10 parts by weight or less, a hard coating with sufficient compatibility with the polyfunctional (meth)acrylate monomer (a) and less turbidity can be obtained.

[0067] (b) The surface modifier may be used alone or in combination of two or more. In the case of combination of two or more, it may contain a perfluoropolyether having an active energy-emitting polymerizable group at one end (one end) of a molecular chain containing a poly(oxy-perfluoroalkylene) group via a urethane bond, and a hydroxyl group at the other end (another end) of the molecular chain.

[0068] (c) Polymerization initiator

[0069] Preferred polymerization initiators in the curable compositions of the present invention are, for example, polymerization initiators that generate free radicals by active energy rays such as electron beams, ultraviolet rays, and X-rays, especially by ultraviolet irradiation.

[0070] Examples of polymerization initiators for (c) above include benzoin derivatives, alkylbenzene derivatives, thioxanone derivatives, azo derivatives, azido derivatives, diazo derivatives, o-quinone diazido derivatives, acylphosphine oxide derivatives, oxime esters, organic peroxides, benzophenone derivatives, dicumarol derivatives, diimidazole derivatives, titanium oxide derivatives, thiols, halogenated hydrocarbons, trichloromethyltriazine derivatives, and ononium salts such as iodonium salts and sulfonium salts. They can be used alone or in combination of two or more. In this invention, considering transparency, surface curing properties, internal curing properties, and film curing properties, it is preferable to use alkylbenzene derivatives or acylphosphine oxide derivatives alone or in combination of two or more as polymerization initiators for (c). By using alkylbenzene derivatives or acylphosphine oxide derivatives, a hard coating with further improved wear resistance can be obtained.

[0071] Examples of the aforementioned alkyl phenyl ketones include, for instance, α-hydroxyalkyl phenyl ketones such as 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 2-hydroxy-1-(4-(2-hydroxyethoxy)phenyl)-2-methylpropane-1-one, and 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropanoyl)benzyl)phenyl)-2-methylpropane-1-one; α-aminoalkyl phenyl ketones such as 2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropane-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one; 2,2-dimethoxy-1,2-diphenylethane-1-one; and methyl phenylglyoxylate.

[0072] Examples of the aforementioned acylphosphine oxides include diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0073] In the curable composition of the present invention, the content of (c) polymerization initiator is preferably 1 to 20 parts by mass, more preferably 2 to 10 parts by mass, relative to 100 parts by mass of the polyfunctional (meth)acrylate monomer described above. By setting the content of (c) polymerization initiator to 1 to 20 parts by mass, the hard coating can be endowed with sufficient hardness and elastic modulus.

[0074] [(d) Conductive polymer materials]

[0075] Conductive polymeric materials refer to conductive materials that can impart antistatic properties to hard coatings obtained from the curable compositions of the present invention.

[0076] Examples of conductive polymer materials described in (d) above are not particularly limited, and examples include poly(3,4-ethylenedioxythiophene) (PEDOT), poly-3,4-ethylenedioxythiophene (PEDOT:PSS) doped with poly-4-styrene sulfonate, and other polythiophene, oligothiophene, polyacetylene, polyaniline, polypyrrole, poly(p-phenylene), polyfluorene, poly(p-phenylene vinylene), and polythiophene vinylene. Among the examples of conductive polymer materials described in (d) above, polythiophene materials are preferred, poly(3,4-ethylenedioxythiophene) (PEDOT) and poly-3,4-ethylenedioxythiophene (PEDOT:PSS) doped with poly-4-styrene sulfonate are more preferred, and poly-3,4-ethylenedioxythiophene (PEDOT:PSS) doped with poly-4-styrene sulfonate is particularly preferred. In the case of (d) the conductive polymer material being a polythiophene, it maintains a stable structure even under high temperature and high humidity conditions, thus possessing the advantage of retaining excellent wear resistance. Here, doping refers to the process of electron donation and acceptance between the conductive polymer chains through charge transfer interactions, or the infiltration or forced addition of a compound (dopant) that facilitates inter-chain movement of charge carriers into the conductive polymer.

[0077] Examples of commercially available conductive polymer materials, such as Denatolon (registered trademark) F-120CD, P-502RG, P-557C, P-200HC, P-801, P-800SL, P-500NT, P-400MP-A, P-560ST, SP-801, SV4stab, SP-548AH, PT-432MF, PT-436, PT-557MF, PT-200HC, PT-432MFT, PT-432NT [made by Nagasecex Co., Ltd.], and Orgacon (registered trademark) ICP1010, ICP102 0, ICP1021, ICP1030, ICP1050, S300, S315, S305plus, EL-P3145, EL-P3155, EL-P3165, EL-P5015, HIL-1005, S305, N-1005, DRY [manufactured by Japan Agford Materials Co., Ltd.], Secureda (registered trademark) AS-D, AS-H, AS-M, AS-Q, AS-S, HC-A, HC-R, SAS-P, SAS-F, ASZ-A, ASZ-B, ASZ-C, ASZ-D, OC-AE, OCK [manufactured by Shin-Etsu Polymer Co., Ltd.] Clevios (registered trademark) PT2, F020, F010, FAS, FAS8, F141M, FEHO, FELO, PT4, PSB6, PH1000, F100T, FET, SV3, SV3STAB, SV4, SV4STAB, PJetOLED, PJet700N, PJet700 [manufactured by Heleus Co., Ltd.], Velasol (registered trademark) WED-S, WED-SM, ED-0130-M, ED-BF4, AN-S03-T [manufactured by Soken Chemical Co., Ltd.], SELFTRON (registered trademark) S standard grade, H high conductivity grade, organic solvent Dosage grades [manufactured by Higashi Sou Co., Ltd.], PEDOT-PSS (product number) 483095, 560596, 655201, 739316, 900181, 768650, 739332, 739324, 768618, 649805, 687316, 649805, 736295, 736309, 736287, 687316, 649813, 649821, 678392, 675288, 483028, 687553, 759791, 660485, 660523, 669210 [manufactured by Sigma-Aldrich Co., Ltd.], etc.

[0078] In the curable composition of the present invention, the content of (d) conductive polymer material is 5.5 to 15 parts by mass, preferably 5.5 to 10 parts by mass, relative to 100 parts by mass of (a) polyfunctional (meth)acrylate monomer. By making the content of (d) conductive polymer material 5.5 to 15 parts by mass relative to 100 parts by mass of (a) polyfunctional (meth)acrylate monomer, the hard coating can be endowed with more sufficient wear resistance, slip properties, and elastic modulus.

[0079] [(e) solvent]

[0080] The curable composition of the present invention may further include (e) a solvent, i.e., it can be formulated into the form of a varnish (film-forming material). As for the solvent (e) mentioned above, it may be appropriately selected as long as it can dissolve or uniformly disperse the components (a) to (d) mentioned above, and takes into account the workability during coating, drying properties before and after curing, etc., which are involved in forming a hard coating as described later. Examples include aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and tetrahydronaphthalene; aliphatic or alicyclic hydrocarbons such as n-hexane, n-heptane, mineral oil, and cyclohexane; halides such as chloromethane, bromomethane, iodomethane, dichloromethane, chloroform, carbon tetrachloride, trichloroethylene, perchloroethylene, and o-dichlorobenzene; esters or ester ethers such as ethyl acetate, propyl acetate, butyl acetate, methoxybutyl acetate, methyl cellosolve acetate, ethyl cellosolve acetate, and propylene glycol monomethyl ether acetate (PGMEA); and diethyl ether, tetrahydrofuran (THF), 1,4-dioxane, methyl cellosolve, ethyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether (PGMEA). Ethers such as propylene glycol monoethyl ether (ME), propylene glycol mono-n-propyl ether, propylene glycol monoisopropyl ether, and propylene glycol mono-n-butyl ether; ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), di-n-butyl ketone, cyclopentanone, and cyclohexanone; alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, 2-ethylhexanol, benzyl alcohol, and ethylene glycol; amides such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methyl-2-pyrrolidone (NMP); sulfoxides such as dimethyl sulfoxide (DMSO); and solvents formed by mixing two or more of these solvents.

[0081] The amount of solvent used in (e) of the curable composition of the present invention is not particularly limited, for example, it is used at a concentration that makes the solids concentration in the curable composition of the present invention 1% to 70% by mass, preferably 5% to 50% by mass. Here, solids concentration (also referred to as non-volatile component concentration) means the content of solids (the substance after removing the solvent component from all components) of the curable composition of the present invention relative to the total mass (total mass) of components (a) to (e) above (and other additives used as needed).

[0082] [Other Additives]

[0083] In addition, in the curable composition of the present invention, as long as the effect of the present invention is not impaired, commonly added additives may be appropriately added as needed, such as polymerization accelerators, polymerization inhibitors, photosensitizers, leveling agents, surfactants, adhesion enhancers, plasticizers, ultraviolet absorbers, light stabilizers, antioxidants, storage stabilizers, conductive additives, inorganic fillers, light diffusing agents, pigments, dyes, defoamers, deaerators, etc.

[0084] <Hard Coating>

[0085] Using the curable composition of the present invention, a hard coating film having a hard coating layer on at least one side (surface) of a film substrate can be manufactured. This hard coating film is also the subject of the present invention, and is suitable for protecting the surface of various display panels such as touch panels and liquid crystal displays.

[0086] The hard coating layer in the hard coating film of the present invention can be formed, for example, by the following method, which includes a step of applying the curable composition of the present invention to a film substrate to form a coating film, a step of removing the solvent by heating if necessary, and a step of curing the coating film by irradiating the coating film with active energy rays such as ultraviolet light.

[0087] As the aforementioned film substrate, various transparent resin films suitable for optical applications can be used. Preferred resin films include, for example, polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), as well as polyurethane, thermoplastic polyurethane (TPU), polycarbonate, polymethacrylate, polystyrene, polyolefin, polyamide, polyimide, and triacetyl cellulose (TAC).

[0088] The aforementioned film substrate can be formed by laminating multiple layers. For example, layers different from the resin film, such as a base coating, an ultraviolet absorption layer, an infrared absorption layer, a near-infrared absorption layer, an electromagnetic wave absorption layer, a color correction layer, a refractive index adjustment layer, a weather-resistant layer, an anti-reflective layer, an anti-static layer, an anti-discoloration layer, an air barrier layer, a water vapor barrier layer, a light scattering layer, and an electrode layer, can be laminated on the surface of the resin film as lower layers of the hard coating. Multiple lower layers of the hard coating can also be laminated. There are no particular limitations on the layers laminated on the surface of the resin film, as long as they do not impair the effects of the present invention.

[0089] It should be noted that, in the laminate, there is a laminate having one or more hard coating layers on at least one side (surface) of the above-mentioned membrane substrate, and a laminate having a lower layer with a further hard coating layer between the membrane substrate and the hard coating layer.

[0090] The coating method for coating the above-mentioned film substrate can appropriately include casting coating, spin coating, doctor blade coating, dip coating, roller coating, spray coating, bar coating, mold coating, inkjet coating, and printing methods (relief printing, gravure printing, offset printing, screen printing, etc.). Among these, roll-to-roll coating is suitable. Furthermore, considering the coating properties of the film, relief printing, especially gravure coating, is preferred. It should be noted that it is preferable to filter the curable composition beforehand using a filter with a pore size of approximately 0.2 μm to 5 μm before coating. It should also be noted that, during coating, a solvent may be added to the curable composition if necessary to form a varnish. Various solvents listed in [(e) Solvents] above can be used as solvents in this case.

[0091] After forming a coating film by coating the curable composition onto the aforementioned film substrate, the coating film is pre-dried by heating means such as a heating plate or oven to remove the solvent (solvent removal process), if necessary. The heating and drying conditions at this time are preferably set to approximately 40°C to 120°C for 30 seconds to 10 minutes. After drying, the coating film is cured by irradiation with active energy rays such as ultraviolet light. Examples of active energy rays include ultraviolet light, electron beams, and X-rays, with ultraviolet light being particularly preferred. The light source used for ultraviolet irradiation can be sunlight, chemical lamps, low-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, xenon lamps, UV-LEDs, electrodeless lamps, etc. Furthermore, polymerization can be completed by post-baking, specifically by heating with means such as a heating plate or oven.

[0092] The thickness of the aforementioned hard coating is, for example, 1 μm to 20 μm, 1 μm to 15 μm, or 1 μm to 10 μm. When the thickness of the hard coating meets the above range, it exhibits both excellent hardness and flexibility, thus being advantageous for application in flexible display devices. It offers the advantages of being able to manufacture hard coatings that are thin, possess excellent wear resistance, excellent sliding properties, and excellent elastic modulus. The thickness of the aforementioned hard coating also includes the thickness after curing.

[0093] [Display device]

[0094] Using the hard coating film of the present invention, a display device having a hard coating film on at least one side (surface) of a display panel can be manufactured. This display device is also the subject of the present invention, and is suitable for protecting the surfaces of various display devices such as liquid crystal displays, plasma displays, organic light-emitting diode devices, flexible displays, etc. Furthermore, the above-described display device is not limited to the examples described above, and all applicable display devices known in the art can be exemplified.

[0095] Example

[0096] The present invention will be described in more detail below with examples, but the present invention is not limited to the following examples.

[0097] It should be noted that the apparatus and conditions used in the preparation of the samples and the analysis of their physical properties in the embodiments are as follows.

[0098] (1) Coating is performed using a bar coater.

[0099] Device: Automatic Film Applicator AB3125 manufactured by TQC Sheen

[0100] Rod: A-Bar OSP-22, manufactured by Irotron Co., Ltd., maximum wet film thickness 22μm (equivalent to wire rod #9)

[0101] Rod: A-Bar OSP-30, manufactured by Irotron Co., Ltd., maximum wet film thickness: 30 μm (equivalent to wire rod #12)

[0102] Rod: A-Bar OSP-42, manufactured by Irotron Co., Ltd., maximum wet film thickness 42 μm (equivalent to wire rod #16)

[0103] Coating speed: 4m / min

[0104] (2) Oven

[0105] Equipment: Sanji Keiso (Co., Ltd.) 2-layer cleanroom drying oven (top and bottom type) PO-250-45-D

[0106] (3) UV curing

[0107] Device: CV-110QC-G manufactured by Hiroshima Co., Ltd.

[0108] Lamp: H-bulb electrodeless lamp manufactured by Herus Corporation

[0109] (4) Gel permeation chromatography (GPC)

[0110] Device: HLC-8420GPC manufactured by Toseo Co., Ltd.

[0111] Pillar: TSKgel (registered trademark) manufactured by Higashi Sou Co., Ltd. G2000HXL, G3000HXL

[0112] Column temperature: 40℃

[0113] Eluent: Tetrahydrofuran

[0114] Detector: UV

[0115] (5) Abrasion resistance test

[0116] Apparatus: TriboGear Type: 30H reciprocating wear testing machine manufactured by Shin-Tung Science Co., Ltd.

[0117] Scanning speed: 0.5 m / min

[0118] Scanning distance: 15mm

[0119] (6) Contact angle measurement, surface energy

[0120] Device: DropMaster DM-501 manufactured by Kyowa Interface Science Co., Ltd.

[0121] Measurement temperature: 23℃

[0122] Solvents: water, diiodomethane

[0123] (7) Surface resistance measurement

[0124] Device: High resistivity meter Haikou-UP MCP-HT450 manufactured by Nitto Seiko Amanita Co., Ltd. (formerly Mitsubishi Chemical Amanita Co., Ltd.)

[0125] Probe: URS probe

[0126] Applied voltage: 100V

[0127] (8) Determination of dynamic friction coefficient

[0128] Apparatus: TRIBOGEAR (registered trademark), a load-variable friction and wear testing system manufactured by Shin-Tung Science Co., Ltd. TYPE: HHS2000

[0129] Probe: 0.6mmR sapphire needle

[0130] Load capacity: 200g

[0131] Scanning speed: 2mm / second

[0132] Scanning distance: 10mm

[0133] (9) Indentation hardness

[0134] Device: iNano Nano Indenter manufactured by Toyo Technica Co., Ltd.

[0135] Indenter: Triangular pyramid indenter Berkovich

[0136] Measurement temperature: 23℃

[0137] Maximum indentation load: 50mN

[0138] Maximum indentation depth: 1500nm

[0139] Load holding time: 1 second

[0140] In addition, the abbreviations have the following meanings.

[0141] Ac1: Multifunctional acrylate [Toa Synthetic Co., Ltd. Aronics (Registered Trademark) MT-3010]

[0142] Ac2: Ethylene oxide modified polyfunctional acrylate [Daiichi Kogyo Pharmaceutical Co., Ltd. New France (registered trademark) MF-001]

[0143] Ac3: Polyfunctional carbamate acrylate [Kenjo Kogyo Co., Ltd. Art Regimen (Registered Trademark) UN-908]

[0144] C1: PEDOT / PSS aqueous dispersion [Sigma-Aldrich PEDOT / PSS 3.0%~4.0% by mass aqueous dispersion, high conductivity grade, product number 655201]

[0145] P1: PEDOT / PSS Granules [Sigma-Aldrich PEDOT / PSS Product No. 768618]

[0146] PFPE1: A perfluoropolyether with the following structure [Fomblin (registered trademark) T4, manufactured by Solebes Petroleum Corporation, which has two hydroxyl groups at each end of the molecular chain containing a poly(oxy-perfluoroalkylene) group instead of poly(oxy-perfluoroalkylene) group]

[0147] In the above formula, m represents the number of repeating units -(CF2CF2O)- and n represents the number of repeating units -(CF2O)-, and satisfies 5≤(m+n)≤40, where m and n each independently represent integers greater than 0.

[0148] BEI: 1,1-Bis(acryloyloxymethyl)ethyl isocyanate [Rezonak Corporation (registered trademark) BEI]

[0149] DOTDD: Dioctyltin dineodecaate [Nitto Kasei Corporation Neostar (Registered Trademark) U-830]

[0150] O2959: 2-Hydroxy-1-(4-(2-hydroxyethoxy)phenyl)-2-methylpropane-1-one [Omnirad (registered trademark) 2959 manufactured by IGM Resins]

[0151] S2: A perfluoropolyether containing a total of four active energy-emitting polymerizable groups at both ends of a molecular chain containing a poly(oxy-perfluoroalkylene) group [Fluorolink (registered trademark) AD-1700 manufactured by Solbeys Corporation, 70% by mass solution of non-volatile components, weight-average molecular weight (Mw) of 3973, dispersity (Mw / Mn) of 2.1, and fluorine content of 29% by mass in the perfluoropolyether compound as determined by combustion ion chromatography].

[0152] HBM: Methyl 2-hydroxyisobutyrate

[0153] PGME: Propylene Glycol Monomethyl Ether

[0154] PGMEA: Propylene Glycol Monomethyl Ether Acetate

[0155] EtOH: Ethanol

[0156] [Manufacturing Example 1] Manufacturing of a perfluoropolyether (S1) with four acryloyl groups attached to both ends of a molecular chain containing poly(oxy-perfluoroalkyl) groups via urethane bonds.

[0157] 1.19 g (0.5 mmol) of PFPE1, 0.52 g (2.2 mmol) of BEI, 0.017 g of DOTDD (0.01 times the total mass of PFPE1 and BEI), and 1.67 g of PGMEA were added to a threaded tube. The mixture was stirred with a stir bar at room temperature (approximately 23 °C) for 24 hours to obtain a 50% by mass PGMEA solution of the target compound S1. The obtained S1 had a weight-average molecular weight (Mw) of 2,300 and a dispersion (Mw / Mn) of 1.0, determined by GPC and converted to polystyrene.

[0158] [Manufacturing Example 2] Preparation of Conductive Polymer Material C2

[0159] Add water to 1.00g of P1, dilute with EtOH to make the solid concentration 1% by mass and the water concentration 5% by mass, and prepare conductive polymer material C2.

[0160] [Examples 1 to 6, Comparative Examples 1 to 6]

[0161] A curable composition having the solids concentration described in Table 1 is prepared by mixing the components listed in Table 1. It should be noted that solids here refer to components other than the solvent. Furthermore, in Table 1, [parts] indicates [parts by mass], and [%] indicates [% by mass].

[0162] Multifunctional (meth)acrylate monomers: 100 parts by weight of the multifunctional (meth)acrylate monomers listed in Table 1

[0163] Surface modifiers: The surface modifiers listed in Table 1 shall be used in the amounts listed in Table 1 (converted to solids).

[0164] Polymerization initiator: 3 parts by weight of O2959

[0165] Conductive polymer materials: The conductive polymer materials listed in Table 1 shall be used in the quantities listed in Table 1 (converted to solids).

[0166] ※C1 is a 3.5% by mass aqueous dispersion, converted according to solids content.

[0167] Solvent: The solvents listed in Table 1, in the amounts listed in Table 1.

[0168]

[0169] A curable composition was applied using a rod coater onto an A4-sized PET film [Toray Industries, Inc., Lumira (registered trademark) U403 (also known as U40), 50 μm thick], on which an easy-bonding primer was formed on both sides, to obtain a coating film. The coating film was dried in an oven at 60°C for 3 minutes to remove the solvent. The resulting film was then irradiated with an exposure dose of 700 mJ / cm² under a nitrogen atmosphere. 2 The film is exposed to UV light to form a hard coating (cured film) with a thickness of about 5 μm.

[0170] The homogeneity of the curable composition, as well as the hydrophobicity, surface energy, coefficient of kinetic friction, indentation hardness, indentation modulus, abrasion resistance, chemical resistance, and antistatic properties of the resulting hard coating were evaluated. The evaluation procedures for hydrophobicity, surface energy, coefficient of kinetic friction, indentation hardness, indentation modulus, abrasion resistance, chemical resistance, and antistatic properties are shown below. The results are presented in Table 2.

[0171] [Composition homogeneity]

[0172] Visually inspect the appearance of each prepared curable composition and evaluate it according to the following criteria.

[0173] A: Clear solution (no suspended matter, sediment, or phase separation)

[0174] C: Any one of the following exists: suspended solids, settled solids, and phase separation.

[0175] [Hydrophobicity]

[0176] Apply 3 μL of water to the surface of the hard coating and measure the contact angle θ after 5 seconds a total of 5 times. The average value is evaluated according to the following criteria.

[0177] A: θ > 105 degrees

[0178] B: 100 degrees ≤ θ ≤ 105 degrees

[0179] C: θ < 100 degrees

[0180] Surface energy

[0181] Apply 3 μL of water or 1 μL of diiodomethane to the surface of the hard coating and measure the contact angle θ after 5 seconds five times. Calculate the surface energy from the average contact angle of these solvents.

[0182] [Coefficient of kinetic friction]

[0183] The dynamic friction coefficient μk of the hard coating surface was determined using the above-mentioned friction and wear test system.

[0184] [Indentation hardness, indentation elastic modulus]

[0185] The indentation hardness and indentation elastic modulus of the hard coating surface were measured using the nanoindenter described above.

[0186] [Abrasion Resistance]

[0187] The hard-coated surface was rubbed 10,000 times with a cylindrical rubber eraser [Minoan Rubber Stick, Φ6.0mm] mounted on the aforementioned reciprocating abrasion tester under a load of 1 kg. 3 μL of water was applied to the rubbed area, and the contact angle θ after 5 seconds was measured five times. The average value was evaluated according to the following criteria.

[0188] A: θ > 95 degrees

[0189] B: 90 degrees ≤ θ ≤ 95 degrees

[0190] C: θ < 90 degrees

[0191] Chemical resistance

[0192] After adding ethanol to the hard coating surface, a 1 kg load was applied using a cylindrical eraser [Minoan Rubber Stick, Φ6.0 mm] mounted on the aforementioned reciprocating abrasion tester, and the surface was rubbed back and forth 3000 times. 3 μL of water was then applied to the rubbed area, and the contact angle θ after 5 seconds was measured five times. The average value was evaluated according to the following criteria.

[0193] A: θ > 95 degrees

[0194] B: 90 degrees ≤ θ ≤ 95 degrees

[0195] C: θ < 90 degrees

[0196] [Antistatic properties]

[0197] A hard coating was placed on the Teflon (registered trademark) surface of the resistivity test stage (レジテーブル) UFL (accompanying the above-mentioned high resistivity meter), and the probe was pressed onto the surface of the hard coating. The surface resistance value was measured 5 times after 10 seconds, and the average value was calculated.

[0198]

[0199] As shown in Table 2, the hard coatings obtained from curable compositions containing 5.5 to 15 parts by mass of conductive polymer material relative to 100 parts by mass of polyfunctional (meth)acrylate monomers exhibit superior antistatic and wear resistance properties compared to hard coatings obtained from curable compositions without conductive polymer material (Comparative Example 1). These hard coatings (Examples 1 to 6) have a water contact angle of 90 degrees or more, a dynamic friction coefficient of 0.30 or less, a surface energy of 35 dyne / cm or less, an indentation hardness of 0.25 GPa or more and less than 0.45 GPa, and an indentation elastic modulus of 3 GPa or more.

[0200] The curable composition of Comparative Example 2 contains the same type of conductive polymer as the curable compositions of Examples 1 to 4, but with a lower content of conductive polymer. The surface resistivity of the hard coating obtained from the curable composition of Comparative Example 2 is 1 × 10⁻⁶. 14 The surface resistivity is above Ω / □, resulting in poor wear resistance. The curable composition of Comparative Example 3 has poor homogeneity due to the excessive content of conductive polymer material. The hard coating obtained from the curable composition of Comparative Example 4 has a surface resistivity of 1×10⁻⁶. 11 It exhibits antistatic properties with an Ω / □ coating, but due to the lack of surface modifiers, it suffers from poor hydrophobicity, high surface energy, and poor antifouling properties. Furthermore, it results in a high coefficient of kinetic friction and poor sliding properties.

Claims

1. A curable composition for forming a hard coating, comprising: (a) Multifunctional (meth)acrylate monomers, (b) Surface modifiers, (c) Polymerization initiators and (d) Conductive polymer materials, The content of the conductive polymer material in (d) is 5.5 to 15 parts by mass relative to 100 parts by mass of the polyfunctional (meth)acrylate monomer in (a); For the hard coating that is the cured product of the curable composition for forming the hard coating, the water contact angle of the surface after the abrasion resistance test is 90 degrees or more. The coefficient of dynamic friction on the surface of the hard coating is below 0.

30. The surface energy of the hard coating is below 35 dyne / cm. When the surface of the hard coating is measured using the nanoindentation method, the indentation hardness is greater than or equal to 0.25 GPa and less than 0.45 GPa, and the indentation elastic modulus measured using the nanoindentation method is greater than or equal to 3 GPa.

2. The curable composition for forming a hard coating according to claim 1, wherein the (d) conductive polymer material comprises poly(3,4-ethylenedioxythiophene).

3. The curable composition for forming a hard coating according to claim 2, wherein the (d) conductive polymeric material comprises poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonic acid.

4. The curable composition for forming a hard coating according to claim 1, wherein the content of the conductive polymer material (d) is 5.5 to 10 parts by weight relative to 100 parts by weight of the polyfunctional (meth)acrylate monomer (a).

5. The curable composition for forming a hard coating according to claim 1, wherein the (b) surface modifier comprises a perfluoropolyether having at least two (meth)acryloyloxy groups at the ends of a molecular chain containing a poly(oxy-perfluoroalkylene) group as shown in formula [1] via urethane bonds. In the above formula [1], PFPE represents a poly(oxy-perfluoroalkylene) group having at least one of repeating units -(CF2CF2O)- and repeating units -(CF2O)-, and these repeating units are bonded by block bonding, random bonding, or block bonding and random bonding. This indicates the bonding site of the -O- group to the urethane bond.

6. The curable composition for forming a hard coating according to claim 5, wherein the (b) surface modifier comprises a perfluoropolyether, wherein the perfluoropolyether has, at the end of the molecular chain containing the poly(oxyperfluoroalkylene) group shown in formula [1], a group represented by formula [A1] or formula [A2], respectively, bonded by the urethane bond. In the above equations [A1] and [A2], R 1 and R 2 Each element independently represents a hydrogen atom or a methyl group, and the black dots represent the bonding sites of the -NH- group to the urethane bond.

7. The curable composition for forming a hard coating according to claim 1, further comprising (e) a solvent.

8. A hard coating film having a hard coating layer on at least one surface of a film substrate, wherein the hard coating layer is a cured product of the hard coating forming curable composition according to any one of claims 1 to 7.

9. A display device comprising the hard coating of claim 8.

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