Curable composition for forming a hard coat layer comprising urethane (meth)acrylate and surface-modified silica particles

Abstract

[Problem] To provide a material for forming a hard coat layer that has both excellent abrasion resistance and excellent stretchability, which are usually in a trade-off relationship. [Solution] A curable composition according to the present invention, which contains (a) 100 parts by mass of a urethane (meth)acrylate, (b) from 5 parts by mass to 70 parts by mass of silica particles which are surface-modified with a silane coupling agent that has at least one nitrogen-containing proton-donating group selected from the group consisting of an amino group, an amide group, a urea group, a thiourea group, a thiourethane group, a ureido group and a thioureido group, (c) from 0.05 part by mass to 10 parts by mass of a perfluoropolyether which has an active energy ray-polymerizable group at an end of a molecular chain that contains a poly(oxyperfluoroalkylene) group, and (d) from 1 part by mass to 20 parts by mass of a polymerization initiator which generates radicals by means of an active energy ray.

Description

[Technical field]

[0001] The present invention relates to a curable composition useful as a material for forming a hard coat layer applied to the surface of various display elements such as flexible displays, and relates to a curable composition capable of forming a hard coat layer that is excellent in abrasion resistance and stretchability and can also be imparted with antistatic properties. [Background technology]

[0002] Smartphones have now become the most common form of mobile phone and have become indispensable in our daily lives. A cover glass is used on the surface of a smartphone to prevent the display from being scratched. In recent years, bendable displays, so-called flexible displays, have been developed as the above-mentioned displays. Flexible displays are expected to have a wide range of applications as displays that can be deformed by bending and rolling up, etc. However, glass is generally hard and difficult to bend back, so it cannot be applied to flexible displays. Therefore, instead of glass, attempts have been made to apply a plastic film with a hard coat layer having scratch resistance to the surface of a flexible display to prevent scratches. When a flexible display having a plastic film with a hard coat layer applied to its surface is curved with the display side facing outward (i.e., with the hard coat layer facing outward), a stress in the tensile direction is generated in the hard coat layer on the outermost surface, so the hard coat layer is required to have a certain degree of extensibility.

[0003] In addition, a method for imparting scratch resistance to a hard coat layer generally involves, for example, forming a high-density crosslinked structure, i.e., forming a crosslinked structure with low molecular mobility to increase surface hardness and provide resistance to external forces. Currently, the most commonly used material for forming these hard coat layers is a multifunctional acrylate-based material that undergoes three-dimensional crosslinking by radicals. However, due to its high crosslinking density, multifunctional acrylate-based materials usually have poor stretchability. Thus, there is a trade-off between the stretchability and scratch resistance of the hard coat layer, and the challenge is to achieve both properties at the same time.

[0004] As one of the methods to improve scratch resistance, a method of adding a silicone or fluorine-based surface modifier to the curable composition forming the hard coat layer to impart slipperiness to the cured film surface has been known. In addition, a technology for hard coat layers that aims to achieve both scratch resistance and stretchability by combining a multifunctional acrylate with highly hard silica particles has been reported (Patent Document 1).

[0005] On the other hand, when a hard coat film is used as a front protective material for a display, it is sometimes required to have antistatic properties in order to prevent adhesion of dust and other particles due to static electricity generated during lamination and to prevent malfunction of the display. 10 It is desirable for the resistance to be on the order of Ω / □. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2011-131409 A Summary of the Invention [Problem to be solved by the invention]

[0007] In the hard coat layer containing silica fine particles proposed so far in Patent Document 1, the physical interaction between the polyfunctional acrylate and the silica fine particles is weak, making it difficult to obtain sufficient scratch resistance, and the stretchability is also not at a satisfactory level. The present invention aims to provide a curable composition capable of forming a hard coat layer that is compatible with scratch resistance and stretchability and can further impart antistatic properties. [Means for solving the problem]

[0008] A first aspect of the present invention is a curable composition comprising: (a) 100 parts by mass of a urethane (meth)acrylate; (b) 5 to 70 parts by mass of silica particles surface-modified with a silane coupling agent having at least one nitrogen-containing proton-donating group selected from the group consisting of an amino group, an amide group, a urea group, a thiourea group, a thiourethane group, a ureido group, and a thioureido group; (c) 0.05 to 10 parts by mass of a perfluoropolyether having an active energy ray-polymerizable group at an end of a molecular chain containing a poly(oxyperfluoroalkylene) group; and (d) 1 to 20 parts by mass of a polymerization initiator that generates radicals when exposed to active energy rays.

[0009] The (a) urethane (meth)acrylate is, for example, a reaction product of (a1) a (meth)acrylate compound having at least one hydroxy group and (a2) an isocyanate compound having at least two isocyanate groups. The (a2) isocyanate compound is, for example, at least one compound selected from the group consisting of compounds represented by the following formulas [1] to [4]. [ka] (In the above formula, R 1 , R 2 , R 3 and R 4 each represents a hydrocarbon group having 4 to 12 carbon atoms; R 0 represents a residue of a monohydric alcohol, and R 5 represents a hydrocarbon group having 2 to 6 carbon atoms, and m represents 2, 3, or 4.

[0010] The (a) urethane (meth)acrylate is, for example, at least one of urethane (meth)acrylates having any one of the partial structures represented by the following formulae [1'] to [4']. [ka] (In the above formula, R 1 , R 2 , R 3 and R 4 each represents a hydrocarbon group having 4 to 12 carbon atoms; R 0 represents a residue of a monohydric alcohol, and R 5 represents a hydrocarbon group having 2 to 6 carbon atoms, and m represents 2, 3, or 4.

[0011] The (b) silica particles are obtained by modifying the surfaces of fine silica particles having an average particle size of, for example, 40 nm to 500 nm with a silane coupling agent having the nitrogen-containing proton-donating group.

[0012] The nitrogen-containing proton-donating group is preferably at least one group selected from the group consisting of a urea group, a thiourea group, and a ureido group.

[0013] The (c) perfluoropolyether has an active energy ray-polymerizable group at the end of the molecular chain containing the poly(oxyperfluoroalkylene) group, for example via a urethane bond.

[0014] The (c) perfluoropolyether has at least two active energy ray-polymerizable groups at the terminals of the molecular chain containing the poly(oxyperfluoroalkylene) group, for example via a urethane bond.

[0015] The (c) perfluoropolyether has at least two active energy ray-polymerizable groups at each of both ends of the molecular chain containing the poly(oxyperfluoroalkylene) group, for example via a urethane bond.

[0016] The poly(oxyperfluoroalkylene) group of the perfluoropolyether (c) may be, for example, a repeating unit -[CF 2 O]- and / or repeating unit-[CF 2 CF 2 When the repeating unit has both repeating units, the repeating units are bonded in a block manner, a random manner, or a combination of a block bond and a random bond.

[0017] The molecular chain containing the poly(oxyperfluoroalkylene) group has, for example, a structure represented by the following formula [5]. [ka] (In the above formula [5], n represents the repeating unit -[CF 2 CF 2 O]- and the number of repeating units -[CF 2 and the total number of the repeating units -[CF 2 CF 2 O]- and the repeating unit -[CF 2 O]- are bonded in a block bond, a random bond, or a block bond and a random bond.

[0018] The curable composition of the present invention may further include an antistatic agent (e). The antistatic agent (e) includes, for example, metal oxide particles. The metal oxide particles include, for example, an oxide of at least one element selected from the group consisting of tin, zinc, and indium. The metal oxide particles include, for example, tin oxide to which a dopant may be added. The metal oxide particles include, for example, at least one of phosphorus-doped tin oxide and tin oxide whose surface is coated with antimony pentoxide.

[0019] The curable composition of the present invention may further comprise (f) a solvent.

[0020] A second aspect of the present invention is a cured film obtained from the curable composition of the present invention.

[0021] A third aspect of the present invention is a hardcoat film comprising a hardcoat layer on at least one surface of a film substrate, the hardcoat layer being made of a cured film obtained from the curable composition of the present invention.

[0022] The hard coat layer is formed, for example, by a method including a step of applying the curable composition of the present invention onto a film substrate to form a coating film, and a step of irradiating the coating film with active energy rays to cure it.

[0023] The hard coat layer is formed, for example, by a method including a step of applying the curable composition of the present invention onto a film substrate to form a coating film, a step of removing the solvent from the coating film by heating, and a step of irradiating the coating film with active energy rays to cure it.

[0024] The hard coat layer has a thickness of, for example, 1 μm to 20 μm.

[0025] A fourth aspect of the present invention is a method for producing a laminate, comprising the steps of applying the curable composition of the present invention onto a film substrate to form a coating film, and irradiating the coating film with active energy rays to cure it. Effect of the Invention

[0026] According to the present invention, it is possible to provide a curable composition useful for forming a cured film and a hard coat layer that have both excellent scratch resistance and high stretchability even in a thin film having a thickness of 1 μm to 20 μm. In addition, according to the present invention, it is possible to provide a hard coat film having a cured film obtained from the curable composition or a hard coat layer made of the cured film, and it is possible to provide a hard coat film having excellent scratch resistance and stretchability, which are in a trade-off relationship. Furthermore, according to the present invention, it is possible to provide a curable composition useful for forming a cured film and a hard coat layer that is imparted with antistatic properties in addition to the above-mentioned scratch resistance and stretchability, and a hard coat film having a hard coat layer that is excellent in these three properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] <Curable composition> Each component of the curable composition of the present invention will be described below. [(a) Urethane (meth)acrylate] In the curable composition of the present invention, the (a) urethane (meth)acrylate is not particularly limited as long as it is a compound having at least two (meth)acryloyl groups and at least one urethane bond [-NH-C(=O)O-] in one molecule. The (a) urethane (meth)acrylate is, for example, a reaction product obtained by reacting (a1) a (meth)acrylate compound having at least one hydroxyl group with (a2) an isocyanate compound having at least two isocyanate groups by a known method.

[0028] Examples of the (a1) (meth)acrylate compound having at least one hydroxy group include 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate, 2-(2-hydroxyethoxy)ethyl acrylate, 2-(2-hydroxyethoxy)ethyl methacrylate, glycerin diacrylate, glycerin dimethacrylate, pentaerythritol triacrylate, pentaerythritol trimethacrylate, dipentaerythritol pentaacrylate, and dipentaerythritol pentamethacrylate.

[0029] Examples of the (a2) isocyanate compound having at least two isocyanate groups include tetramethylene diisocyanate, pentamethylene diisocyanate, hexamethylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, 2,4'-diisocyanate, 2,6'-diisocyanate, 1,3-xylylene diisocyanate, 1,4'-diisocyanate, 2,6'-diisocyanate, 1,5'-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, dicyclohexylmethane 4,4'-diisocyanate, 2,4'-diisocyanate, 2,6'-diisocyanate, 2,6'-diisocyanate, 2,7'-diisocyanate, 2,7'-diisocyanate, 2,8'-diisocyanate, 2,9'-diisocyanate, 2,8'-diisocyanate, 2,9'-diisocyanate, 2,10'-diisocyanate, 2,10'-diisocyanate, 2,11'-diisocyanate, 2,12'-diisocyanate, 2,13'-diisocyanate, 2,14'-diisocyanate, 2,15'-diisocyanate, 2,16'-diisocyanate, 2,17'-diisocyanate, 2,18'-diisocyanate , 2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, and the allophanate polyisocyanates represented by the formula [1], the biuret polyisocyanate represented by the formula [2], the adduct polyisocyanate represented by the formula [3], and the isocyanurate polyisocyanate represented by the formula [4], which are obtained by polymerizing these diisocyanates, are listed.

[0030] In the above formulas [1] to [4], R 1 , R 2 , R 3 and R 4 is a group obtained by removing two isocyanate groups from the above diisocyanate, and an example of this is a hexamethylene group. 0 is a group obtained by removing an OH group from a monohydric alcohol that reacts with the above diisocyanate to form a urethane bond. 5 is a group obtained by removing all OH groups from a dihydric alcohol, trihydric alcohol or tetrahydric alcohol which reacts with the above diisocyanate to form a urethane bond.

[0031] (a) As the urethane (meth)acrylate, a commercially available product can be used. For example, Art Resin (registered trademark) UN-3320HA, UN-3320HC, UN-3320HS, UN-904, UN-906S, UN-901T, UN-905, and UN-952 (all manufactured by Negami Chemical Industries, Ltd.), EBECRYL (registered trademark) 220, 284, 4683, 4858, 8807, 4220, 4738, 4820, 8311, 8465, 9260, 8701, 4265, 4666, 1290, 5129, K Examples of such compounds include RM8667, RM8200, RM8200AE, RM8530, RM8904, RM8531BA, and RM8452 (all manufactured by Daicel-Allnex Co., Ltd.), UA-306H, UA-306T, UA-306I, UA-510H, and UF-8001G (all manufactured by Kyoeisha Chemical Co., Ltd.), Aronix (registered trademark) M-1100 and Aronix M-1200 (all manufactured by Toagosei Co., Ltd.), and U-6LPA, U-10HA, U-10PA, UA-1100H, U-15HA, UA-53H, UA-33H, and UA-122P (all manufactured by Shin-Nakamura Chemical Co., Ltd.).

[0032] The urethane (meth)acrylate (a) in the curable composition of the present invention may be used alone or in combination of two or more.

[0033] [(b) Silica particles] In the curable composition of the present invention, the (b) silica particles are surface-modified with a silane coupling agent having at least one nitrogen-containing proton-donating group selected from the group consisting of amino, amide, urea, thiourea, thiourethane, ureido, and thioureido groups. In addition, the (b) silica particles can be imparted with extensibility without impairing scratch resistance by interaction with the (a) urethane (meth)acrylate.

[0034] The shape of the silica particles (hereinafter referred to as "unmodified silica particles") before the surface is modified with the silane coupling agent having the above-mentioned nitrogen-containing proton-donating group is not particularly limited, and may be, for example, approximately spherical like beads or may be amorphous like powder, but approximately spherical particles are preferred, approximately spherical particles having an aspect ratio of 1.5 or less are more preferred, and truly spherical particles are most preferred.

[0035] The average particle size of the unmodified silica particles is in the range of 40 nm to 500 nm, for example, 40 nm to 350 nm, preferably 60 nm to 250 nm, or 70 nm to 250 nm. Here, the average particle size (nm) is the 50% volume diameter (median diameter) obtained by measuring by a laser diffraction / scattering method based on the Mie theory. By setting the average particle size of the (b) silica particles within the above numerical range, a cured film having excellent scratch resistance can be obtained. The particle size distribution of the (b) silica particles is not particularly limited, but it is preferable that the particles are monodispersed fine particles with a uniform particle size. Furthermore, it is preferable to select the average particle size of the (b) silica particles so that the thickness of the cured film obtained from the curable composition of the present invention described later satisfies the range of average particle size b / film thickness a=0.01 to 1.0.

[0036] As the unmodified silica particles, for example, colloidal silica having the above average particle size can be suitably used, and as the colloidal silica, silica sol can be used.As the silica sol, aqueous silica sol produced by a known method using an aqueous sodium silicate solution as a raw material, and organosilica sol obtained by replacing the water, which is the dispersion medium of the aqueous silica sol, with an organic solvent can be used.In addition, silica sol obtained by hydrolyzing and condensing alkoxysilane such as methyl silicate and ethyl silicate in an organic solvent such as alcohol in the presence of a catalyst (for example, an alkali catalyst such as ammonia, an organic amine compound, sodium hydroxide), or organosilica sol obtained by solvent-substitution of the silica sol with another organic solvent can also be used.

[0037] Examples of the organic solvent in the organosilica sol include lower alcohols such as methanol, ethanol, and 2-propanol; ketones such as methyl ethyl ketone (MEK) and methyl isobutyl ketone (MIBK); linear amides such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMAc); cyclic amides such as N-methyl-2-pyrrolidone (NMP); ethers such as γ-butyrolactone; glycols such as ethyl cellosolve and ethylene glycol; and acetonitrile. The replacement of water, which is the dispersion medium of the aqueous silica sol, with an organic solvent and the replacement with another organic solvent of interest can be carried out by a conventional method such as distillation or ultrafiltration. The viscosity of the organosilica sol is, for example, 0.6 mPa·s to 100 mPa·s at 20°C.

[0038] Commercially available products of the above aqueous silica sol and organosilica sol include, for example, the SeaHostar (registered trademark) KE series (manufactured by Nippon Shokubai Co., Ltd.) and the Snowtex (registered trademark) series (manufactured by Nissan Chemical Industries, Ltd.).

[0039] Examples of the nitrogen-containing proton donating group include an amino group, an amide group (-C(=O)NH- group), a urea group (-NHC(=O)NH- group), a thiourea group (-NHC(=S)NH- group), a thiourethane group (-NHC(=S)S- group), a ureido group (-NHC(=O)NH 2 group) and thioureido group (-NHC(=S)NH 2 Among these nitrogen-containing proton donating groups, amino group, urea group, thiourea group and ureido group are preferred, and in consideration of the transparency of the cured film, urea group, thiourea group and ureido group are particularly preferred. The silane coupling agent used for surface modification of the unmodified silica particles may have one or more of the above nitrogen-containing proton donating groups, or may have multiple kinds of nitrogen-containing proton donating groups.

[0040] (b) Silica particles can be prepared by mixing the silane coupling agent having the nitrogen-containing proton donating group with unmodified silica particles in the presence of water or alcohol. The silane coupling agent having the nitrogen-containing proton donating group generates a silanol group by hydrolysis, and bonds with the silanol group present on the surface of the unmodified silica particles by condensation reaction. As a result, it is considered that silica particles whose surface is modified with the silane coupling agent having the nitrogen-containing proton donating group are formed. Specifically, for example, a colloidal solution (silica sol) of unmodified silica particles and the silane coupling agent having the nitrogen-containing proton donating functional group can be mixed to prepare silica particles whose surface is modified with the silane coupling agent. The colloidal solution and the silane coupling agent are mixed at room temperature or while heating. From the viewpoint of reaction efficiency, it is preferable to mix while heating, and when mixing while heating, the heating temperature can be appropriately selected according to the type of solvent. The heating temperature can be, for example, 30°C or higher. The mixing ratio of the silane coupling agent having the nitrogen-containing proton-donating functional group to the unmodified silica particles depends on the size of the unmodified silica particles and the type of the nitrogen-containing proton-donating functional group. For example, 2 ) the number of molecules of the silane coupling agent is 0.01 to 5, preferably 0.05 to 2, and more preferably 0.1 to 1. Here, the surface area of ​​the unmodified silica particles is calculated from the specific surface area measured by the nitrogen adsorption method (BET method).

[0041] In the curable composition of the present invention, the content of the (b) silica particles is 5 to 70 parts by mass, for example 10 to 60 parts by mass, and preferably 10 to 50 parts by mass, based on 100 parts by mass of the (a) urethane (meth)acrylate. The (b) silica particles may be used alone or in combination of two or more kinds.

[0042] [(c) Perfluoropolyether] The (c) perfluoropolyether preferred in the curable composition of the present invention has an active energy ray polymerizable group at the end of the molecular chain containing a poly(oxyperfluoroalkylene) group via a urethane bond. The end of the molecular chain of the perfluoropolyether may be all ends or some ends of the molecular chain. When the molecular chain of the perfluoropolyether is linear, all ends and some ends of the molecular chain are both ends and one end of the linear molecular chain, respectively. Examples of the linking group between the poly(oxyperfluoroalkylene) group and the urethane bond include a hydrocarbon group having an ether bond, and at least one of the hydrogen atoms of the hydrocarbon group may be substituted with a fluorine atom. In the curable composition of the present invention, the (c) perfluoropolyether plays a role as a surface modifier in the hard coat layer formed from the curable composition of the present invention. In addition, the (c) perfluoropolyether has excellent compatibility with the (a) urethane (meth)acrylate, so that it is possible to form a hard coat layer that is suppressed from becoming cloudy and has a transparent appearance.

[0043] From the viewpoint of obtaining a cured film having good scratch resistance, the poly(oxyperfluoroalkylene) group is -[CF 2 O]-(oxyperfluoromethylene group) and -[CF 2 CF 2 A group having both of the repeating units, i.e., oxyperfluoroethylene group and oxyperfluoroalkylene group, is preferred. In this case, the bond of these oxyperfluoroalkylene groups may be either block bond or random bond. The number of repeating units of the oxyperfluoroalkylene group is preferably in the range of 5 to 30, more preferably in the range of 7 to 21, as the total number of repeating units.

[0044] The molecular chain containing the poly(oxyperfluoroalkylene) group preferably has a structure represented by the following formula [5]. [ka] In formula [5], n represents the repeating unit -[CF2 CF 2 O]- and the number of repeating units -[CF 2 O]-, and is preferably an integer in the range of 5 to 30, more preferably an integer in the range of 7 to 21. 2 CF 2 O]- and the number of repeating units -[CF 2 The ratio of the number of repeating units to the number of repeating units is preferably in the range of 2:1 to 1:2, and more preferably in the range of about 1:1. The bonds of these repeating units may be either block bonds or random bonds.

[0045] Examples of the active energy ray polymerizable group include (meth)acryloyl group and vinyl group. (c) Perfluoropolyether is not limited to those having one active energy ray polymerizable group at the end of the molecular chain containing poly(oxyperfluoroalkylene) group, but may have two or more active energy ray polymerizable groups. Examples of the end structure containing active energy ray polymerizable group include the structures of formulas [A1] to [A5] shown below, and structures in which the acryloyl group in these structures is replaced with a methacryloyl group. Among these structures, the structures of formulas [A3], [A4] and [A5] having two or more active energy ray polymerizable groups, and structures in which the acryloyl group in these structures is replaced with a methacryloyl group are preferred. [ka]

[0046] In the curable composition of the present invention, the content of (c) perfluoropolyether is 0.05 to 10 parts by mass, preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the (a) urethane (meth)acrylate. When the content of (c) perfluoropolyether is 0.05 parts by mass or more, sufficient scratch resistance can be imparted to the hard coat layer, and when the content of (c) perfluoropolyether is 10 parts by mass or less, the hard coat layer is sufficiently compatible with (a) urethane (meth)acrylate, and less cloudy can be obtained.

[0047] In addition, (c) perfluoropolyether can be used alone or in combination of two or more. When combining two or more, perfluoropolyether may be included that has an active energy ray polymerizable group via urethane bond at one end (one end) of molecular chain containing poly(oxyperfluoroalkylene) group, and has a hydroxyl group at the other end (other end) of the molecular chain. In addition, (c) perfluoropolyether can be added with the condition that it does not have a poly(oxyalkylene) group between the poly(oxyperfluoroalkylene) group and the urethane bond, and between the poly(oxyperfluoroalkylene) group and the hydroxyl group.

[0048] [(d) Polymerization initiator] The (d) polymerization initiator preferred in the curable composition of the present invention is, for example, a polymerization initiator that generates radicals when exposed to active energy rays such as electron beams, ultraviolet rays, and X-rays, particularly when exposed to ultraviolet rays.

[0049] Examples of the (d) polymerization initiator include benzoins, alkylphenones, thioxanthones, azos, azides, diazos, o-quinone diazides, acylphosphine oxides, oxime esters, organic peroxides, benzophenones, biscoumarins, bisimidazoles, titanocenes, thiols, halogenated hydrocarbons, trichloromethyltriazines, and onium salts such as iodonium salts and sulfonium salts. These polymerization initiators may be used alone or in combination of two or more. In the present invention, from the viewpoints of transparency, surface curability, and thin film curability, it is preferable to use alkylphenones as the (d) polymerization initiator. By using alkylphenones, a cured film with improved scratch resistance can be obtained.

[0050] Examples of the alkylphenones include α-hydroxyalkylphenones such as 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2-hydroxy-1-(4-(2-hydroxyethoxy)phenyl)-2-methylpropan-1-one, and 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one; α-aminoalkylphenones such as 2-methyl-1-(4-(methylthio)phenyl)-2-morpholinopropan-1-one and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butan-1-one; 2,2-dimethoxy-1,2-diphenylethan-1-one; and methyl phenylglyoxylate.

[0051] In the curable composition of the present invention, the content of the polymerization initiator (d) is 1 to 20 parts by mass, preferably 2 to 10 parts by mass, based on 100 parts by mass of the urethane (meth)acrylate (a).

[0052] [(e) Antistatic agent] The curable composition of the present invention may contain an optional component (e) an antistatic agent. Examples of the antistatic agent (e) include an antistatic agent containing an organic conductive polymer such as PEDOT / PSS or metal oxide particles. As the metal oxide particles, fine particles having a primary particle diameter of 4 nm to 100 nm can be used. By setting the primary particle diameter of the metal oxide particles within the above numerical range, antistatic properties can be imparted without affecting scratch resistance and extensibility, and a cured film that leads to the realization of transparency can be obtained. In the present invention, the primary particle diameter of the metal oxide particles refers to the particle diameter of each particle observed using a transmission electron microscope.

[0053] The metal oxide particles may include, for example, an oxide of at least one element selected from the group consisting of tin, zinc, and indium. Specifically, tin oxide (SnO 2), tin-doped indium oxide (ITO), fluorine-doped tin oxide (FTO), antimony-doped tin oxide (ATO), phosphorus-doped tin oxide (PTO), gallium-doped zinc oxide (GZO), aluminum-doped zinc oxide (AlZO), antimony-doped zinc oxide (AZO), indium-doped zinc oxide or zinc oxide-doped indium oxide (IZO), and indium gallium zinc oxide (IGZO). Among these, oxides of the above elements to which a dopant has been added are preferred as the antistatic agent, and phosphorus-doped tin oxide (PTO) is particularly preferred.

[0054] The above-mentioned metal oxide particles can also include surface-coated metal oxide particles having a metal oxide core and the surface of which is coated with an acidic or basic oxide. Examples of the core can include the above-mentioned metal oxide particles such as tin oxide, as well as titanium oxide, titanium oxide-tin oxide complex, zirconium oxide-tin oxide complex, tungsten oxide-tin oxide complex, and titanium oxide-zirconium oxide-tin oxide complex. Examples of the acidic or basic oxide can include antimony pentoxide, silicon oxide-antimony pentoxide complex, and silicon oxide-tin oxide complex.

[0055] In the present invention, when the (e) antistatic agent is contained, the content thereof is preferably 10 to 100 parts by mass, more preferably 10 to 90 parts by mass, based on 100 parts by mass of the (a) urethane (meth)acrylate. The (e) antistatic agent may be used alone or in combination of two or more kinds.

[0056] [(f) Solvent] The curable composition of the present invention may contain a solvent (f) as an optional component, i.e., may be in the form of a varnish. The solvent (f) may be appropriately selected in consideration of the solubility and dispersibility of the components (a) to (d) and the optional component (e), as well as the workability during application of the curable composition for forming a cured film (hard coat layer) described below, drying properties before and after curing, etc.

[0057] Examples of the solvent (f) include aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, and tetralin; aliphatic or alicyclic hydrocarbons such as n-hexane, n-heptane, mineral spirits, and cyclohexane; halides such as methyl chloride, methyl bromide, methyl iodide, 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); diethyl ether, tetrahydrofuran (THF), 1,4-dioxane, methyl cellosolve, ethyl cellosolve, butyl cellosolve, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and the like. Examples of the solvent include ethers such as polypropylene glycol ether (PGME), 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, and cyclohexanone; alcohols such as methanol, ethanol, n-propanol, isopropyl alcohol, n-butanol, isobutyl alcohol, tert-butyl alcohol, 2-ethylhexyl alcohol, benzyl alcohol, and ethylene glycol; amides such as N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), and N-methyl-2-pyrrolidone (NMP); and sulfoxides such as dimethyl sulfoxide (DMSO), as well as mixtures of two or more of these solvents.

[0058] In addition, a high boiling point solvent can be used for the purpose of controlling the dispersibility of the (b) silica particles during drying after application of the curable composition. Examples of such solvents include cyclohexyl acetate, propylene glycol diacetate, 1,3-butylene glycol diacetate, 1,4-butanediol diacetate, 1,6-hexanediol diacetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, dipropylene glycol methyl ether acetate, 3-methoxybutyl acetate, ethylene glycol, diethylene glycol, propylene glycol, 1,3-butylene glycol, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, 3-methoxybutanol, dipropylene glycol dimethyl ether, and dipropylene glycol methylpropyl ether.

[0059] In the curable composition of the present invention, the content of the (f) solvent is not particularly limited, but is, for example, a concentration such that the solid content concentration of the curable composition of the present invention is 1% by mass to 70% by mass, preferably 5% by mass to 50% by mass. Here, the solid content concentration (also referred to as non-volatile content concentration) represents the content of the solid content (all components excluding the solvent component) relative to the total mass (total mass) of the (a) to (d) components of the curable composition of the present invention, and the (e) component, which is an optional component, the (f) component, and other additives.

[0060] [Other additives] Furthermore, to the curable composition of the present invention, generally added additives such as a polymerization inhibitor, a photosensitizer, a leveling agent, a surfactant, an adhesion imparting agent, a plasticizer, an ultraviolet absorber, a storage stabilizer, an inorganic filler, a pigment, a dye, etc. may be appropriately blended, if necessary, either alone or in combination of two or more kinds, as long as the effects of the present invention are not impaired.

[0061] <Cured film> The curable composition of the present invention can be applied (coated) on a substrate to form a coating film, and the coating film can be polymerized (cured) by irradiating the coating film with active energy rays to form a cured film, which is also the subject of the present invention. In addition, the above-mentioned cured film can be used as a hard coat layer in a hard coat film described later.

[0062] Examples of the substrate include various resins (polycarbonate, polymethacrylate, polystyrene, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyurethane, thermoplastic polyurethane (TPU), polyolefin, polyamide, polyimide, epoxy resin, melamine resin, triacetyl cellulose (TAC), acrylonitrile-butadiene-styrene copolymer (ABS), acrylonitrile-styrene copolymer (AS), norbornene resin), metal, wood, paper, glass, and slate. The shape of these substrates may be a plate, a film, or a three-dimensional molded body. In addition, on the surface of the substrate, for example, a primer layer, an ultraviolet absorbing layer, an infrared absorbing layer, a near infrared absorbing layer, an electromagnetic wave absorbing layer, a color correction layer, a refractive index adjusting layer, a weather-resistant layer, an antireflection layer, an antistatic layer, a discoloration prevention layer, a gas barrier layer, a water vapor barrier layer, a light scattering layer, an electrode layer, etc. may be formed as a lower layer of the hard coat layer, and a plurality of lower layers of these hard coat layers may be laminated. The layer formed on the surface of the substrate is not particularly limited as long as it does not impair the effects of the present invention.

[0063] The coating method on the substrate may be appropriately selected from cast coating, spin coating, blade coating, dip coating, roll coating, spray coating, bar coating, die coating, inkjet printing, printing (letterpress printing, intaglio printing, lithographic printing, screen printing, etc.), among which the roll-to-roll method can be used. From the viewpoint of thin film coating, it is preferable to use letterpress printing, particularly gravure coating. It is preferable to filter the curable composition of the present invention using a filter having a pore size of about 0.2 μm before coating. When coating, a solvent may be further added to the curable composition as necessary. Examples of the solvent in this case include various solvents listed in [(f) Solvent] above.

[0064] After the curable composition of the present invention is applied onto a substrate to form a coating film, the coating film is pre-dried with a heating means such as a hot plate or oven as necessary to remove the solvent (solvent removal step). The conditions for the heat drying at this time are preferably, for example, 40°C to 120°C and about 30 seconds to 10 minutes. After drying, the coating film is cured by irradiating it with active energy rays such as ultraviolet rays. Examples of active energy rays include ultraviolet rays, electron beams, and X-rays, and ultraviolet rays are particularly preferred. Examples of light sources used for ultraviolet irradiation include sunlight, chemical lamps, low-pressure mercury lamps, high-pressure mercury lamps, metal halide lamps, xenon lamps, and UV-LEDs. Furthermore, the polymerization may be completed by performing post-baking, specifically by heating using a heating means such as a hot plate or oven.

[0065] The thickness of the cured film formed after drying and curing is usually 0.1 to 50 μm, preferably 0.5 to 20 μm.

[0066] <Hard coat film> The curable composition of the present invention can be used to produce a hard coat film having a hard coat layer on at least one side (surface) of a film substrate. The hard coat film is also an object of the present invention, and the hard coat film is suitably used to protect the surfaces of various display elements such as touch panels and liquid crystal displays.

[0067] The hard coat layer in the hard coat film of the present invention can be formed by a method including a step of applying the curable composition of the present invention onto a film substrate to form a coating film, a step of removing the solvent by heating as necessary, and a step of irradiating the coating film with active energy rays such as ultraviolet rays to cure the coating film. A method for producing a hard coat film having a hard coat layer on at least one side of a film substrate, including these steps, is also within the scope of the present invention.

[0068] As the film substrate, various transparent resin films usable for optical applications among the substrates listed in the above-mentioned <cured film> are used. Preferred resin films include, for example, polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), polyurethane, thermoplastic polyurethane (TPU), polycarbonate, polymethacrylate, polystyrene, polyolefin, polyamide, polyimide, and triacetyl cellulose (TAC). The film substrate may be formed by laminating a plurality of layers. For example, a layer different from the resin film, such as a primer layer, an ultraviolet absorbing layer, an infrared absorbing layer, a near infrared absorbing layer, an electromagnetic wave absorbing layer, a color correction layer, a refractive index adjustment layer, a weather-resistant layer, an antireflection layer, an antistatic layer, a discoloration prevention layer, a gas barrier layer, a water vapor barrier layer, a light scattering layer, or an electrode layer, may be laminated on the surface of the resin film as a lower layer of the hard coat layer, or a plurality of lower layers of the hard coat layer may be laminated. The layer to be laminated on the surface of the resin film is not particularly limited as long as it does not impair the effects of the present invention.

[0069] The method for applying the curable composition of the present invention onto the film substrate (coating film forming step) and the method for irradiating the coating film with active energy rays (curing step) can be the methods listed in the above-mentioned <cured film>. When the curable composition of the present invention contains a solvent (in the form of a varnish), the coating film may be dried to remove the solvent after the coating film forming step, if necessary. In this case, the method for drying the coating film (solvent removal step) listed in the above-mentioned <cured film> can be used.

[0070] The thickness (film thickness) of the hard coat layer thus obtained is preferably set to be 1 to 100 times the average particle diameter of the (b) silica particles. For example, the film thickness of the hard coat layer is, for example, 1 μm to 20 μm, preferably 1 μm to 10 μm. EXAMPLES

[0071] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. In the examples, the apparatus and conditions used for preparing samples and analyzing physical properties are as follows.

[0072] (1) Coating with a bar coater Equipment: PM-9050MC manufactured by SMT Co., Ltd. Bar: OSG System Products Co., Ltd. A-Bar OSP-22, maximum wet film thickness 22μm (equivalent to wire bar #9) Coating speed: 4m / min (2) Oven Equipment: Sanki Instruments Co., Ltd. 2-layer clean oven (upper and lower type) PO-250-45-D (3)UV curing Equipment: Heraeus CV-110QC-G Lamp: Heraeus H-bulb electrodeless lamp (4) Gel Permeation Chromatography (GPC) Equipment: Tosoh Corporation HLC-8220GPC Column: Shodex (registered trademark) GPC K-804L, GPC K-805L manufactured by Showa Denko K.K. Column temperature: 40℃ Eluent: Tetrahydrofuran Detector: RI (5) Scratch resistance test Equipment: Reciprocating wear tester TRIBOGEAR TYPE:30S manufactured by Shinto Scientific Co., Ltd. Scanning speed: 5,000 mm / min Scanning distance: 50mm (6) Tensile test Equipment: Shimadzu Corporation, tabletop precision universal testing machine Autograph AGS-10kNX Grip: 1kN manual screw type flat grip Grip teeth: High-strength rubber-coated grip teeth Pulling speed: 10mm / min Measurement temperature: 23℃ (7) Surface resistance measurement Equipment: High resistivity meter Hiresta UP MCP-HT450 manufactured by Nitto Seiko Analytech Co., Ltd. (formerly Mitsubishi Chemical Analytech Co., Ltd.) Probe: URS probe Cashier table: UFL Applied voltage: 10V

[0073] The abbreviations have the following meanings: Polyfunctional acrylate having one hydroxy group (a1-1): Dipentaerythritol pentaacrylate / hexaacrylate mixture [Aronix (registered trademark) M-403 manufactured by Toagosei Co., Ltd., pentaacrylate ratio 50% to 60% (catalog value), estimated hydroxyl value = 63.3 mg KOH / g (calculated assuming pentaacrylate 55% and hexaacrylate 45%)] Allophanate polyisocyanates (a2-1): Allophanate modified hexamethylene diisocyanate [Duranate (registered trademark) A201H, Asahi Kasei Chemicals Corporation, isocyanate group content = 17.2 mass%, bifunctional] Biuret polyisocyanate (a2-2): Biuret modified hexamethylene diisocyanate [Duranate (registered trademark) 24A-100, Asahi Kasei Chemicals Corporation, isocyanate group content = 23.5 mass%, trifunctional] Isocyanurate polyisocyanates (a2-3): Isocyanurate modified hexamethylene diisocyanate [Duranate (registered trademark) TLA-100, Asahi Kasei Chemicals Corporation, isocyanate group content = 23.3 mass%, trifunctional] Adduct polyisocyanate (a2-4): Adduct modified product of hexamethylene diisocyanate [Duranate (registered trademark) P301-75E, manufactured by Asahi Kasei Chemicals Corporation, isocyanate group content = 12.5 mass%, trifunctional] UA5: Urethane acrylate [Art Resin (registered trademark) UN-904 (number of functional groups: 10, weight average molecular weight Mw: 4900) manufactured by Negami Chemical Industries, Ltd.] Silica microparticles s-1: Silica particles with an average particle size of 80 nm [Nissan Chemical Co., Ltd., organosilica sol MA-ST-ZL (solid content concentration 30% by mass, methanol dispersion)] Silica microparticles s-2: Silica particles with an average particle size of 200 nm [Nissan Chemical Co., Ltd., organosilica sol MEK-ST-2040 (solid content concentration 40% by mass, methyl ethyl ketone dispersion)] Silica microparticles S-3: Silica particles with an average particle size of 40 nm [Nissan Chemical Co., Ltd., Organosilica sol MA-ST-L (solid content concentration 30% by mass, methanol dispersion)] Silane coupling agent Si-1: Trimethoxysilane with thiourea group [X-12-1116, manufactured by Shin-Etsu Chemical Co., Ltd.] Silane coupling agent Si-2: Trimethoxysilane with urea group [X-12989MS manufactured by Shin-Etsu Chemical Co., Ltd.] Silane coupling agent Si-3: 3-Ureidopropyltriethoxysilane [Tokyo Chemical Industry Co., Ltd., solids concentration 50% by mass, alcohol solution] Silane coupling agent Si-4: Trimethoxysilane with a hexyl group [KBM-3063, manufactured by Shin-Etsu Chemical Co., Ltd.] Silane coupling agent Si-5: Trimethoxysilane with acryloyl group [KBM-5103, Shin-Etsu Chemical Co., Ltd.] PFPE: Perfluoropolyether having two hydroxyl groups at each end of a molecular chain containing a poly(oxyperfluoroalkylene) group, without a poly(oxyalkylene) group in between [Fomblin (registered trademark) T4, manufactured by Solvay Specialty Polymers] BEI: 1,1-bis(acryloyloxymethyl)ethyl isocyanate [Karenz (registered trademark) BEI, manufactured by Showa Denko K.K.] DOTDD: Dioctyltin dineodecanoate [Neostan (registered trademark) U-830, manufactured by Nitto Kasei Co., Ltd.] SM2: Perfluoropolyether urethane acrylate having a total of four acryloyl groups at both ends of a molecular chain containing a poly(oxyperfluoroalkylene) group [FLUOROLINK (registered trademark) AD-1700, manufactured by Solvay Specialty Polymers, 70% by weight non-volatile solution] SM3: Polydimethylsiloxane having a methacryloyl group at one end [Silaplane (registered trademark) FM-0721, manufactured by JNC Corporation] O2959: 2-hydroxy-1-(4-(2-hydroxyethoxy)phenyl)-2-methylpropan-1-one [OMNIRAD (registered trademark) 2959, manufactured by IGM Resins] MEK: Methyl ethyl ketone MeOH: Methanol Antistatic agent E-1: Phosphorus-doped tin oxide 20% by mass dispersion sol in isopropyl alcohol [Nissan Chemical Co., Ltd., Celnax (registered trademark) CX-S204IP, primary particle diameter: 5 nm to 20 nm, secondary particle diameter: 10 nm to 20 nm] *The primary particle size and secondary particle size here refer to the average particle size measured by observation with a transmission electron microscope. The particle size was measured by dropping the sol onto a copper mesh, drying it, and observing it with a transmission electron microscope (JEM-1020, manufactured by JEOL Ltd.) at an accelerating voltage of 100 kV, and averaging the measurements of 100 particles to obtain the average primary particle size. Antistatic agent E-2: A 30% by mass methanol dispersion sol of core-shell particles with a primary particle diameter of 30 to 40 nm, in which the core is made of tin oxide and the surface is coated with antimony pentoxide [Nissan Chemical Co., Ltd., Celnax (registered trademark) HX-307M1]

[0074] [Production Example 1] Production of surface modifier SM1 In a screw tube, 1.19g (0.5mmol) of PFPE, 0.52g (2.0mmol) of BEI, 0.017g of DOTDD (0.01 times the total mass of PFPE and BEI), and 1.67g of MEK were charged. The resulting mixture was stirred for 72 hours at room temperature (approximately 23°C) using a stirrer tip to obtain a 50% by mass MEK solution of the target compound, surface modifier SM1. The weight average molecular weight Mw of the resulting SM1 measured in terms of polystyrene by GPC was 3,000, and the dispersity (weight average molecular weight Mw / number average molecular weight Mn) was 1.2.

[0075] [How to determine the amount of polyisocyanate to be charged when manufacturing urethane acrylate] When a polyfunctional acrylate (a1-1) having one hydroxy group is reacted with various polyisocyanates (a2-1) to (a2-4) to produce a urethane acrylate, the amount of the polyisocyanate to be charged was calculated using [hydroxyl value of (a1-1) / 561]×(42×100 / isocyanate group content)×[amount of (a1-1) / 100]×(number of NCO groups / number of OH groups).

[0076] [Production Example 2] Production of urethane acrylate UA1 In a screw tube, 10 g of (a1-1) and 2.76 g of allophanate polyisocyanate (a2-1) were charged so that the number of OH groups / the number of NCO groups = 1, and 0.13 g of DOTDD [0.01 times the total mass of (a1-1) and (a2-1)] and 3.22 g of MEK were further charged. The resulting mixture was stirred at room temperature (approximately 23°C) using a stirrer tip until it reached the 2260 cm3 value indicating the isocyanate group. -1 After stirring until the infrared absorption spectrum of disappeared, an 80 mass % MEK solution of the target compound, urethane acrylate UA1, was obtained.

[0077] [Production Example 3] Production of urethane acrylate UA2 In a screw tube, 10 g of (a1-1) and 3.02 g of biuret polyisocyanate (a2-2) were charged so that the number of OH groups / the number of NCO groups was 2 / 3, and 0.13 g of DOTDD [0.01 times the total mass of (a1-1) and (a2-2)] and 2.96 g of MEK were further charged. The resulting mixture was stirred using a stirrer tip at room temperature (approximately 23°C) for about 3 hours, after which 0.33 g of MeOH was charged to eliminate the remaining isocyanate groups, and the 2260 cm3 indicating the isocyanate groups was measured at room temperature (approximately 23°C). -1 After stirring until the infrared absorption spectrum of the above disappeared, an 80 mass % MEK / MeOH solution of the target compound, urethane acrylate UA2, was obtained.

[0078] [Production Example 4] Production of urethane acrylate UA3 In a screw tube, 10 g of (a1-1) and 3.05 g of isocyanurate polyisocyanate (a2-3) were charged so that the number of OH groups / the number of NCO groups was 2 / 3, and 0.13 g of DOTDD [0.01 times the total mass of (a1-1) and (a2-3)] and 2.97 g of MEK were further charged. The resulting mixture was stirred using a stirrer tip at room temperature (approximately 23°C) for about 3 hours, after which 0.33 g of MeOH was charged to eliminate the remaining isocyanate groups, and the 2260 cm3 indicating the isocyanate groups was measured at room temperature (approximately 23°C). -1After stirring until the infrared absorption spectrum of the above disappeared, an 80 mass % MEK / MeOH solution of the target compound, urethane acrylate UA3, was obtained.

[0079] [Production Example 5] Production of urethane acrylate UA4 In a screw tube, 10 g of (a1-1) and 3.73 g of adduct polyisocyanate (a2-4) were charged so that the number of OH groups / the number of NCO groups = 1, and 0.14 g of DOTDD [0.01 times the total mass of (a1-1) and (a2-4)] and 3.47 g of MEK were further charged. The resulting mixture was stirred at room temperature (approximately 23°C) using a stirrer tip until it reached the 2260 cm3 value indicating the isocyanate group. -1 After stirring until the infrared absorption spectrum of disappeared, an 80 mass % MEK solution of the target compound, urethane acrylate UA4, was obtained.

[0080] [Production Example 6] Production of silica fine particles s-4 whose surfaces are modified with a silane coupling agent having a thiourea group In a four-neck flask, 35g of silica fine particles s-1, 0.17g of silane coupling agent Si-1, and 0.18g of water were charged. The mixture obtained was stirred at 65°C for 3 hours using a stirrer tip to obtain a 30% by mass MeOH dispersion of the target compound, silica fine particles s-4, with an average particle size of 80nm, whose surface was modified with a silane coupling agent having a thiourea group.

[0081] [Production Example 7] Production of silica fine particles s-5 whose surfaces are modified with a silane coupling agent having a urea group In a four-neck flask, 30 g of silica fine particles s-1, 0.15 g of silane coupling agent Si-2, and 0.21 g of water were charged. The mixture obtained was stirred for 3 hours at room temperature of 65°C using a stirrer tip to obtain a 30 mass% MeOH dispersion of the target compound, silica fine particles s-5, with an average particle size of 80 nm, whose surface was modified with a silane coupling agent having a urea group.

[0082] [Production Example 8] Production of silica fine particles s-6 whose surfaces are modified with a silane coupling agent having a ureido group In a four-neck flask, 30 g of silica fine particles s-1, 0.27 g of silane coupling agent Si-3, and 0.21 g of water were charged. The mixture obtained was stirred at 65°C for 3 hours using a stirrer tip to obtain a 30 mass% MeOH dispersion of the target compound, silica fine particles s-6, with an average particle size of 80 nm, whose surface was modified with a silane coupling agent having a ureido group.

[0083] [Production Example 9] Production of silica fine particles s-7 whose surfaces are modified with a silane coupling agent having a thiourea group In a four-neck flask, 60 g of silica fine particles s-2, 0.16 g of silane coupling agent Si-1, and 0.55 g of water were charged. The mixture obtained was stirred at 65°C for 3 hours using a stirrer tip to obtain a 40% by mass MEK dispersion of the target compound, silica fine particles s-7, whose surface was modified with a silane coupling agent having a thiourea group and had an average particle size of 200 nm.

[0084] [Production Example 10] Production of silica fine particles s-8 whose surfaces are modified with a silane coupling agent having a thiourea group In a four-neck flask, 35 g of silica fine particles s-3, 0.35 g of silane coupling agent Si-1, and 0.18 g of water were charged. The mixture obtained was stirred at 65°C for 3 hours using a stirrer tip to obtain a 30 mass% MeOH dispersion of the target compound, silica fine particles s-8, modified with a silane coupling agent having a thiourea group and having an average particle size of 40 nm.

[0085] [Production Example 11] Production of silica fine particles s-9 whose surfaces are modified with a silane coupling agent having an acryloyl group In a four-neck flask, 30 g of silica fine particles s-1, 0.12 g of silane coupling agent Si-5, and 0.21 g of water were charged. The mixture obtained was stirred for 3 hours at 65°C using a stirrer tip to obtain a 30 mass% MeOH dispersion of the target compound, silica fine particles s-9, with an average particle size of 80 nm and surface-modified with a silane coupling agent having an acryloyl group.

[0086] [Production Example 12] Production of silica fine particles s-10 whose surfaces are modified with a silane coupling agent having a hexyl group In a four-neck flask, 30 g of silica fine particles s-1, 0.11 g of silane coupling agent Si-4, and 0.21 g of water were charged. The mixture obtained was stirred at 65°C for 3 hours using a stirrer tip to obtain a 30 mass% MeOH dispersion of the target compound, silica fine particles s-10, whose surface was modified with a silane coupling agent having a hexyl group and whose average particle size was 80 nm.

[0087] [Examples 1 to 11, Comparative Examples 1 to 10] The components shown in Table 1 were mixed to prepare a curable composition having the solid content concentration shown in Table 1. The solid content here refers to components other than the solvent and the dispersion medium. In Table 1, [parts] refers to [parts by mass] and [%] refers to [% by mass]. In Table 1, the urethane acrylate, silica fine particles, and surface modifier each refer to a solid content.

[0088] Table 1 [Table 1]

[0089] These curable compositions were applied by a bar coater onto an A4-sized PET film [Lumirror (registered trademark) U403 (also known as U40), manufactured by Toray Industries, Inc., thickness 100 μm] on which a primer layer had been formed by easy-adhesion treatment on both sides, to obtain a coating film. This coating film was dried in an oven at 80° C. for 3 minutes to remove the solvent. The obtained film was then exposed to light at an exposure dose of 300 mJ / cm under a nitrogen atmosphere. 2A hard coat film having a hard coat layer (cured film) was produced by exposing the film to UV light.

[0090] The homogeneity of each curable composition, and the scratch resistance and stretchability of the obtained hard coat film were evaluated. The evaluation procedures are shown below. The results are also shown in Table 2. [Composition homogeneity] The appearance of the curable composition was visually inspected 2 hours after preparation and evaluated according to the following criteria. A: Clear solution (no floating matter or sediment) C: Both floating matter and sediment are present [Scratch resistance] The surface of the hard coat layer of the obtained hard coat film was rubbed 10 times with steel wool [BONSTAR (registered trademark) #0000 (ultrafine)] attached to a reciprocating abrasion tester, with a stroke of 60 mm, and the load shown in Table 2. Thereafter, the degree of damage in the area excluding the range of 5 mm width at both ends of the stroke of 60 mm was visually confirmed and evaluated according to the following criteria A, B, and C. Note that, when assuming actual use as a hard coat layer, at least B is required, and A is preferable. A: No scratches (0 scratches) B: Scratches (1 to 4 scratches, 1 to 9 mm long) C: Scratches (5 or more scratches measuring 1 to 9 mm in length, or 1 or more scratches measuring 1 cm or longer) [Stretchability] The obtained hard coat film was cut into a rectangle with a length of 60 mm and a width of 10 mm to prepare a test piece. The test piece was attached to the grip of a universal testing machine so that 20 mm was gripped from both ends in the longitudinal direction, and a tensile test was performed at 1% intervals so that the stretch ratio (= (increase in the distance between the grippers) ÷ (distance between the grippers) × 100) was 4%, 5%, and 6%. The hard coat film after the tensile test was visually observed to confirm the maximum stretch ratio at which no cracks occurred in the hard coat layer of the test piece. Thereafter, the stretchability improvement rate was calculated using the stretch ratio of the hard coat film prepared using the curable composition (Comparative Example 1, Comparative Example 7, Comparative Example 8, Comparative Example 9, and Comparative Example 10) without silica fine particles as the standard (= 100%), and the value was evaluated as the stretchability according to the following criteria A, B, and C. In addition, when assuming actual use as a hard coat layer, it is required to be at least B, and it is preferable to be A. A: 125% or more B: More than 100% but less than 125% C: 100% or less

[0091] Table 2 [Table 2]

[0092] As shown in Table 1, the curable compositions of Examples 1 to 7 include urethane acrylate UA1 having an allophanate structure, silica fine particles s-4, s-5, s-6, s-7 or s-8 in which the surface of silica fine particles having an average particle size of 40 nm, 80 nm or 200 nm is modified with a silane coupling agent having a nitrogen-containing proton-donating functional group, and perfluoropolyether SM1 or SM2 having an acryloyl group at each end of the molecular chain via a urethane bond as a surface modifier.And as shown in Table 2, the hard coat film having a hard coat layer obtained from the curable composition of Examples 1 to 7 showed better scratch resistance and stretchability than the hard coat film having a hard coat layer obtained from the curable composition of Comparative Example 1 to which silica fine particles were not added.

[0093] On the other hand, the curable composition of Comparative Example 2 contains urethane acrylate UA1, silica fine particles s-1 with unmodified surface, and surface modifier SM1. The hard coat film having a hard coat layer obtained from the curable composition of Comparative Example 2 has inferior scratch resistance compared to the hard coat film having a hard coat layer obtained from the curable composition of Examples 1 to 7 containing urethane acrylate UA1, silica fine particles s-4, s-5 or s-6 surface-modified with a silane coupling agent having a thiourea group, urea group or ureido group, and surface modifier SM1 or SM2. This result suggests that the interaction between the urethane acrylate UA1 and the silica fine particles s-1 is weak.

[0094] Further, the curable composition of Comparative Example 3 contains urethane acrylate UA1, silica fine particles s-9 surface-modified with a silane coupling agent having an acryloyl group, and a surface modifier SM1, and the curable composition of Comparative Example 4 contains urethane acrylate UA1, silica fine particles s-10 surface-modified with a silane coupling agent having a hexyl group, and a surface modifier SM1. The hard coat film having a hard coat layer obtained from the curable composition of Comparative Example 3 showed a strong interaction between the urethane acrylate UA1 and the silica fine particles s-9, excellent in abrasion resistance, but poor in stretchability. In addition, the hard coat film having a hard coat layer obtained from the curable composition of Comparative Example 4 showed a weak interaction between the urethane acrylate UA1 and the silica fine particles s-10, and poor in abrasion resistance.

[0095] On the other hand, in the case of the curable composition of Comparative Example 5, which contains urethane acrylate UA1, silica fine particles s-4 surface-modified with a silane coupling agent having a thiourea group, and polydimethylsiloxane SM3 having a methacryloyl group at one end as a surface modifier, the compatibility of the surface modifier SM3 is poor, and a good composition without floating matter or sedimentation could not be obtained.Furthermore, the hard coat film having a hard coat layer obtained from the curable composition of Comparative Example 6, which does not contain silica fine particles and a surface modifier, was shown to have poor scratch resistance.

[0096] The hard coat film having a hard coat layer obtained from the curable composition of Example 8 containing urethane acrylate UA2 having a biuret structure, silica microparticles s-4, and surface modifier SM1 exhibited superior scratch resistance and stretchability compared to the hard coat film having a hard coat layer obtained from the curable composition of Comparative Example 7 to which no silica microparticles were added.

[0097] The hard coat film having a hard coat layer obtained from the curable composition of Example 9 containing urethane acrylate UA3 having an isocyanurate structure, silica microparticles s-4, and surface modifier SM1 exhibited superior scratch resistance and stretchability compared to the hard coat film having a hard coat layer obtained from the curable composition of Comparative Example 8 to which no silica microparticles were added.

[0098] The hard coat film having a hard coat layer obtained from the curable composition of Example 10 containing urethane acrylate UA4 having an adduct structure, silica microparticles s-4, and surface modifier SM1 exhibited superior scratch resistance and stretchability compared to the hard coat film having a hard coat layer obtained from the curable composition of Comparative Example 9 to which no silica microparticles were added.

[0099] In addition, the hard coat film having a hard coat layer obtained from the curable composition of Example 11 containing the commercially available urethane acrylate UA5, silica fine particles s-4, and surface modifier SM1 showed the same excellent scratch resistance and better stretchability as the hard coat film having a hard coat layer obtained from the curable composition of Comparative Example 10 to which no silica fine particles were added. From the above results, it was suggested that it is possible to improve both scratch resistance and stretchability, which are in a trade-off relationship, by adding silica fine particles s-4 surface-modified with a silane coupling agent having a thiourea group, regardless of the type of urethane acrylate.

[0100] [Examples 12 to 14] The components shown in Table 3 were mixed to prepare a curable composition having a solid content concentration shown in Table 3. The solid content here refers to components other than the solvent and the dispersion medium. In Table 3, [parts] refers to [parts by mass] and [%] refers to [% by mass]. In Table 3, the urethane acrylate, silica fine particles, surface modifier, and antistatic agent each refer to a solid content.

[0101] Table 3 [Table 3]

[0102] These curable compositions were applied by a bar coater onto an A4-sized PET film [Lumirror (registered trademark) U403 (also known as U40) manufactured by Toray Industries, Inc., thickness 100 μm] on which a primer layer had been formed by performing an easy-adhesion treatment on both sides, to obtain a coating film. This coating film was dried in an oven at 60° C. for 3 minutes to remove the solvent. The obtained film was then exposed to light at a dose of 300 mJ / cm under a nitrogen atmosphere. 2 By exposing the film to UV light, a hard coat film having a hard coat layer (cured film) with a layer thickness (film thickness) of approximately 4 μm was produced.

[0103] The obtained hard coat film was evaluated for the above-mentioned [scratch resistance] and [stretchability], as well as for the surface resistance. The procedure for evaluating the surface resistance is shown below. The results are shown in Table 4. [Surface resistance] The hard coat film was placed on the register table of the high resistivity meter with the hard coat layer surface facing up, and the probe was pressed against the hard coat film (hard coat layer). The value after 10 seconds was measured three times, and the average value was taken as the surface resistance value [Ω / □].

[0104] Table 4 [Table 4]

[0105] As shown in Tables 3 and 4, the hard coat films having a hard coat layer obtained from the curable compositions of Examples 12 to 14 using antistatic agents e-1 or e-2 exhibited excellent scratch resistance and stretchability, as well as antistatic properties.

Claims

1. (a) 100 parts by mass of urethane (meth)acrylate, (b) 5 to 70 parts by mass of silica particles surface-modified with a silane coupling agent having at least one nitrogen-containing proton-donating group selected from the group consisting of a urea group, a thiourea group, a ureido group, and a thioureido group; (c) 0.05 to 10 parts by mass of a perfluoropolyether having an active energy ray-polymerizable group at the end of a molecular chain containing a poly(oxyperfluoroalkylene) group, and (d) 1 to 20 parts by mass of a polymerization initiator that generates radicals when exposed to active energy rays 1. A curable composition comprising:

2. The curable composition according to claim 1, wherein the (a) urethane (meth)acrylate is a reaction product of (a1) a (meth)acrylate compound having at least one hydroxy group and (a2) an isocyanate compound having at least two isocyanate groups.

3. The curable composition according to claim 2, wherein the (a2) isocyanate compound is at least one compound selected from the group consisting of compounds represented by the following formulas [1] to [4]: 【Chemistry 1】 (In the above formula, R １ , R ２ , R ３ and R ４ each represents a hydrocarbon group having 4 to 12 carbon atoms; R ０ represents a residue of a monohydric alcohol, R ５ represents a hydrocarbon group having 2 to 6 carbon atoms, and m represents 2, 3, or 4.

4. The curable composition according to claim 1 or 2, wherein the (a) urethane (meth)acrylate is at least one of urethane (meth)acrylates having any one of partial structures represented by the following formulas [1'] to [4']: 【Chemistry 2】 (In the above formula, R １ , R ２ , R ３ and R ４ each represents a hydrocarbon group having 4 to 12 carbon atoms; R ０ represents a residue of a monohydric alcohol, R ５ represents a hydrocarbon group having 2 to 6 carbon atoms, and m represents 2, 3, or 4.

5. The curable composition according to any one of claims 1 to 4, wherein the (b) silica particles are silica fine particles having an average particle diameter of 40 nm to 500 nm, the surfaces of which are modified with a silane coupling agent having the nitrogen-containing proton donating group.

6. The curable composition according to claim 1 , wherein the nitrogen-containing proton-donating group is at least one group selected from the group consisting of a urea group, a thiourea group, and a ureido group.

7. The curable composition according to claim 1 , wherein the (c) perfluoropolyether has an active energy ray-polymerizable group at an end of a molecular chain containing the poly(oxyperfluoroalkylene) group via a urethane bond.

8. The curable composition according to any one of claims 1 to 7, wherein the (c) perfluoropolyether has at least two active energy ray-polymerizable groups via urethane bonds at an end of a molecular chain containing the poly(oxyperfluoroalkylene) group.

9. The curable composition according to any one of claims 1 to 7, wherein the (c) perfluoropolyether has at least two active energy ray-polymerizable groups via urethane bonds at each of both ends of a molecular chain containing the poly(oxyperfluoroalkylene) group.

10. The poly(oxyperfluoroalkylene) group of the perfluoropolyether (c) is a repeating unit -[CF ２ O]- and / or repeating unit -[CF ２ CF ２ 10]-, and when both repeating units are present, the repeating units are bonded by block bonds, random bonds, or both block bonds and random bonds. The curable composition according to any one of claims 1 to 9,

11. The curable composition according to claim 10, wherein the molecular chain containing the poly(oxyperfluoroalkylene) group has a structure represented by the following formula [5]: 【Chemistry 3】 (In the above formula [5], n represents the repeating unit -[CF ２ CF ２ O]- and the number of repeating units -[CF ２ The total number of the repeating units -[CF ２ CF ２ O]- and the repeating unit -[CF ２ O]- is bonded by block bonds, random bonds, or block bonds and random bonds.

12. The curable composition of claim 1 , further comprising: (e) an antistatic agent.

13. The curable composition of claim 12 , wherein the (e) antistatic agent comprises metal oxide particles.

14. 14. The curable composition of claim 13, wherein the metal oxide particles comprise an oxide of at least one element selected from the group consisting of tin, zinc, and indium.

15. 15. The curable composition of claim 14, wherein the metal oxide particles comprise optionally doped tin oxide.

16. 16. The curable composition according to claim 13, wherein the metal oxide particles include at least one of phosphorus-doped tin oxide and tin oxide having a surface coated with antimony pentoxide.

17. The curable composition of claim 1 , further comprising: (f) a solvent.

18. A cured film obtained from the curable composition according to any one of claims 1 to 17.

19. A hard coat film comprising a hard coat layer on at least one surface of a film substrate, the hard coat layer comprising the cured film according to claim 18.

20. A hard coat film having a hard coat layer on at least one surface of a film substrate. The hard coat layer is formed by a method including the steps of: applying the curable composition according to any one of claims 1 to 17 onto a film substrate to form a coating film; and irradiating the coating film with active energy rays to cure it.

21. 20. A hard coat film comprising a hard coat layer on at least one surface of a film substrate, the hard coat layer being formed by a method including the steps of: applying the curable composition according to claim 17 onto a film substrate to form a coating film; removing the solvent from the coating film by heating; and irradiating the coating film with active energy rays to cure the coating film.

22. 22. The hard coat film according to claim 19, wherein the hard coat layer has a thickness of 1 μm to 20 μm.

23. A method for producing a laminate, comprising: applying the curable composition according to claim 1 onto a film substrate to form a coating film; and irradiating the coating film with active energy rays to cure the coating film.

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