Curable composition for forming hard coat layer

Abstract

[Problem] To provide a curable composition capable of forming a hard coat layer having excellent chemical resistance. [Solution] This curable composition for forming a hard coat layer comprises (a) a polyfunctional (meth)acrylate monomer, (b) a surface modifier, and (c) a polymerization initiator, and also comprises, as (d) at least one solvent, (d1) a solvent having a standard boiling point higher than 150°C but not higher than 205°C. (d1) The solvent having a standard boiling point higher than 150°C but not higher than 205°C is contained in an amount of 10-150 parts by mass with respect to 100 parts by mass of (a) the polyfunctional (meth)acrylate monomer, and is contained in an amount of 4-50 parts by mass with respect to 100 parts by mass of the curable composition for forming a hard coat layer.

Description

Curable composition for forming hard coat layer

[0001] The present invention relates to a curable composition useful as a material for forming a hard coat layer, and particularly to a curable composition capable of forming a hard coat layer having excellent chemical resistance.

[0002] Plastic materials such as acrylic resin, polycarbonate resin, ABS resin, etc. have well-balanced mechanical properties as well as excellent moldability, light weight, and transparency, and taking advantage of these characteristics, they are widely used in housings and packaging materials for electronic devices and cosmetics, as well as optical applications such as lenses, etc. In order to improve the various properties of such plastic materials, such as surface hardness, barrier properties, antifouling properties, flame retardancy, and heat resistance, a widely used method is to form a hard coat layer on the surface of the material by UV curing using a multifunctional acrylate containing a photopolymerization initiator.

[0003] In addition, development of bendable displays, so-called flexible displays, is underway for use in smartphones and other devices. Flexible displays can be deformed, for example, by bending and rolling, and are expected to have a wide range of applications as portable displays. Typically, a cover glass is used on the surface of a smartphone or other device to prevent scratches on the display. However, glass is generally rigid and cannot be bent back, making it difficult to apply to flexible displays. Therefore, instead of glass, attempts have been made to apply plastic films with hard coat layers that have scratch resistance to the surface of flexible displays to prevent scratches. Hard coat layers used in such smartphone displays are required to have scratch resistance to prevent scratches on the display surface caused by fingernails or other objects when operating the device, as well as anti-fouling properties (water and oil repellency) to prevent fingerprints from adhering to the display.

[0004] As a material for forming the hard coat layer (hard coat film), for example, a hard coat film-forming composition containing a polyfunctional polymerizable monomer, organic fine particles having an average primary particle diameter of 80 nm or more and 500 nm or less, and a solvent has been proposed as a hard coat film that combines scratch resistance with transparency and anti-blocking properties (Patent Document 1). Furthermore, a coating composition containing inorganic oxide fine particles, a hydrolyzable group-containing organosilicon compound, water or an acid aqueous solution, a curing catalyst, and a solvent has been disclosed as a composition for forming a hard coat film that suppresses appearance defects such as interference patterns on high refractive index lenses and has good weather-resistant adhesion (Patent Document 2). Furthermore, a coating composition containing (A) composite metal oxide particles, (B') a hydrolyzate of a hydrolyzable organosilicon compound, (C) water, (D) a water-soluble organic solvent, and (E) a curing catalyst has been disclosed as a composition for forming a hard coat layer that has excellent adhesion and scratch resistance even after weather resistance testing (Patent Document 3).

[0005] Patent Document 1: JP 2013-256562 A, International Publication No. 2019 / 151311, International Publication No. 2010 / 082566

[0006] In recent years, due to the spread of new viral infections, wiping the screens of smartphones and other devices with disinfectant alcohol has become more common and habitual. Although there have been studies on improving transparency, scratch resistance, adhesion, and stain resistance in hard coat layers, the chemical resistance has not been at a satisfactory level.

[0007] As a result of extensive research to achieve the above object, the present inventors have found that the chemical resistance of the resulting hard coat layer can be improved by using a high-boiling point solvent having a boiling point of 150° C. or higher and 205° C. or lower as the solvent used in a composition for forming a hard coat layer, and have completed the present invention. Note that the above-mentioned patent documents describe that the use of a high-boiling point solvent or the combined use of two solvents with different boiling points makes it easier to form a hard coat layer and enables the formation of a smooth hard coat film and a thick film, but do not discuss chemical resistance.

[0008] That is, in a first aspect, the present invention relates to a curable composition for forming a hard coat layer, comprising: (a) a polyfunctional (meth)acrylate monomer; (b) a surface modifier; (c) a polymerization initiator; and (d) a solvent, wherein the (d) solvent includes (d1) a solvent having a standard boiling point of greater than 150°C and not greater than 205°C, and the (d1) solvent having a standard boiling point of greater than 150°C and not greater than 205°C is included in an amount of 10 to 150 parts by mass per 100 parts by mass of the (a) polyfunctional (meth)acrylate monomer and 4 to 50 parts by mass per 100 parts by mass of the curable composition for forming a hard coat layer. In a second aspect, the present invention relates to the curable composition for forming a hard coat layer according to the first aspect, wherein the (d) solvent further includes (d2) a solvent having a standard boiling point of 150°C or less.

[0013] As a third aspect, the present invention relates to the curable composition for forming a hard coat layer according to the first or second aspect, wherein the (d1) solvent having a normal boiling point of more than 150°C and not more than 205°C is selected from the group consisting of propylene glycol monobutyl ether, diethylene glycol ethyl methyl ether, γ-butyrolactone, 3-methoxy-1-butanol, propylene glycol, and hexylene glycol. As a fourth aspect, the present invention relates to the curable composition for forming a hard coat layer according to the first or second aspect, which does not contain inorganic particles or organic particles. As a fifth aspect, the present invention relates to the curable composition for forming a hard coat layer according to the first or second aspect, which further contains (e) a conductive polymer material. As a sixth aspect, the present invention relates to the composition for forming a hard coat layer according to the first or second aspect, in which the (b) surface modifier is a perfluoropolyether containing a poly(oxyperfluoroalkylene) group, represented by the following formula [2], and the composition contains 0.05 parts by mass to 10 parts by mass of the perfluoropolyether containing a poly(oxyperfluoroalkylene) group per 100 parts by mass of the (a) polyfunctional (meth)acrylate monomer: (In formula [2], A represents a structure represented by the following formula [A3] or a structure in which the acryloyl group in the structure is substituted with a methacryloyl group, and PFPE represents the poly(oxyperfluoroalkylene) group (wherein L １The side directly bonded to is an oxy end, and the side bonded to the oxygen atom is a perfluoroalkylene end. １ represents an alkylene group having 2 or 3 carbon atoms substituted with 1 to 3 fluorine atoms, each m independently represents an integer of 1 to 5, and the partial structure (A-NHC(═O)O) ｍ L ２ - represents a structure represented by the following formula [B3]. As a seventh aspect, the present invention relates to a hard coat film comprising a hard coat layer on at least one surface of a film substrate, the hard coat layer being a cured product of the hard coat layer-forming curable composition according to the first aspect or the second aspect. As an eighth aspect, the present invention relates to a display device comprising the hard coat film according to the seventh aspect.

[0009] According to the present invention, it is possible to provide a curable composition for forming a hard coat layer that has excellent chemical resistance while maintaining properties such as scratch resistance, stretchability, and water repellency. Furthermore, according to the present invention, it is possible to provide a hard coat film having a surface provided with a hard coat layer formed from the curable composition, and it is possible to provide a hard coat film that has excellent chemical resistance.

[0010] <Curable Composition for Forming Hard Coat Layer> The curable composition for forming a hard coat layer (hereinafter also simply referred to as the curable composition) of the present invention comprises: (a) a polyfunctional (meth)acrylate monomer; (b) a surface modifier; (c) a polymerization initiator; and (d) a solvent, wherein the (d) solvent includes at least (d1) a solvent having a standard boiling point of greater than 150°C and not greater than 205°C, wherein the (d1) solvent having a standard boiling point of greater than 150°C and not greater than 205°C is contained in an amount of 10 to 150 parts by mass per 100 parts by mass of the (a) polyfunctional (meth)acrylate monomer and 4 to 50 parts by mass per 100 parts by mass of the curable composition for forming a hard coat layer. Hereinafter, each of the components (a) to (d) will be described.

[0011] [(a) Polyfunctional (meth)acrylate Monomer] In the curable composition of the present invention, examples of the (a) polyfunctional (meth)acrylate monomer include monomers selected from the group consisting of polyfunctional (meth)acrylate compounds described below, as well as monomers selected from the group consisting of polyfunctional urethane (meth)acrylate compounds, oxyalkylene-modified products thereof (oxyalkylene-modified polyfunctional monomers), and monomers selected from the group consisting of lactone-modified polyfunctional (meth)acrylate compounds. The (a) polyfunctional (meth)acrylate monomer can be used alone or in combination of two or more from the group consisting of the various (meth)acrylate compounds described above. In the present invention, the term "(meth)acrylate compound" includes both acrylate compounds and methacrylate compounds; for example, "(meth)acrylic acid" includes acrylic acid and methacrylic acid. Furthermore, in the present invention, the term "(meth)acryloyl group" includes both acryloyl groups and methacryloyl groups.

[0012] In the present invention, preferred examples of the (a) polyfunctional (meth)acrylate monomer include polyfunctional monomers having at least two (meth)acryloyl groups in one molecule, more preferably polyfunctional monomers having at least three, for example, 3 to 6, (meth)acryloyl groups in one molecule, or monomers selected from the group consisting of oxyalkylene-modified polyfunctional (meth)acrylate compounds having at least three (meth)acryloyl groups in one molecule.

[0013] Among the (a) polyfunctional (meth)acrylate monomers, examples of the polyfunctional (meth)acrylate compounds (but compounds having no urethane bond) include: Trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, glycerin tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, ethoxylated dipentaerythritol hexa(meth)acrylate, ethoxylated glycerin tri(meth)acrylate, ethoxylated bisphenol A di(meth)acrylate, 1,3-propanediol di(meth)acrylate, 1,3-butanediol di(meth)acrylate acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 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, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, tricyclo[5.2.1.0 ２，６] decanedimethanol di(meth)acrylate, dioxane glycol 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-adamantanedimethanol di(meth)acrylate, polyethylene glycol di(meth)acrylate, and polypropylene glycol di(meth)acrylate can be mentioned. Among these, preferred polyfunctional (meth)acrylate compounds include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and mixtures of two or more thereof.

[0014] The polyfunctional urethane (meth)acrylate compound is a compound having a plurality of acryloyl groups or methacryloyl groups in one molecule and having one or more urethane bonds [—NHC(═O)O—], and may further have a urea bond [—NHC(═O)NH—]. Examples of the polyfunctional urethane (meth)acrylate compound include a compound obtained by reacting a polyfunctional isocyanate with a (meth)acrylate having a hydroxy group, and a compound obtained by reacting a polyfunctional isocyanate with a (meth)acrylate having a hydroxy group, and a polyol, but the polyfunctional urethane (meth)acrylate compound that can be used in the present invention is not limited to these examples.

[0015] Examples of the polyfunctional isocyanate include tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, and hexamethylene diisocyanate. Examples of the (meth)acrylate having a hydroxy group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and tripentaerythritol hepta(meth)acrylate. Examples of the polyol include diols such as ethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and dipropylene glycol; polyester polyols that are 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.

[0016] In the oxyalkylene-modified product (oxyalkylene-modified polyfunctional monomer), examples of the oxyalkylene-modified include oxymethylene-modified, oxyethylene-modified, and oxypropylene-modified. Examples of the oxyalkylene-modified polyfunctional monomer include oxyalkylene-modified compounds of the polyfunctional (meth)acrylate compounds or polyfunctional urethane (meth)acrylate compounds. The oxyalkylene-modified polyfunctional monomers can also be used alone or in combination of two or more. Examples of the oxyalkylene-modified polyfunctional (meth)acrylate compounds include (meth)acrylate compounds of polyols modified with oxyalkylene. Examples of the polyols include glycerin, diglycerin, triglycerin, tetraglycerin, pentaglycerin, hexaglycerin, decaglycerin, polyglycerin, trimethylolpropane, ditrimethylolpropane, pentaerythritol, and dipentaerythritol.

[0017] In the lactone-modified polyfunctional (meth)acrylate compound, the lactone used for the lactone modification can be ε-caprolactone. Examples of the lactone-modified polyfunctional (meth)acrylate compound include 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.

[0018] [(b) Surface Modifier] As the (b) surface modifier used in the curable composition of the present invention, a fluorine-based surface modifier can be used. Specific examples of the fluorine-based surface modifier include perfluoropolyethers containing a poly(oxyperfluoroalkylene) group.

[0019] The number of carbon atoms in the alkylene group in the poly(oxyperfluoroalkylene) group is not particularly limited, but preferably is 1 to 4. That is, the poly(oxyperfluoroalkylene) group refers to a group having a structure in which divalent fluorocarbon groups having 1 to 4 carbon atoms and oxygen atoms are alternately linked, and the oxyperfluoroalkylene group refers to a group having a structure in which divalent fluorocarbon groups having 1 to 4 carbon atoms and oxygen atoms are linked. Specifically, -[OCF ２ ]-(oxyperfluoromethylene group), -[OCF ２ CF ２ ]-(oxyperfluoroethylene group), -[OCF ２ CF ２ CF ２ ]-(oxyperfluoropropane-1,3-diyl group), -[OCF ２ C (CF ３ )F]-(oxyperfluoropropane-1,2-diyl group). The oxyperfluoroalkylene groups may be used singly or in combination of two or more, in which case the bonding of the multiple types of oxyperfluoroalkylene groups may be either block bonding or random bonding.

[0020] Among these, from the viewpoint of obtaining a cured film having good stain resistance, scratch resistance, and chemical resistance, the poly(oxyperfluoroalkylene) group is preferably —[OCF ２ ]-(oxyperfluoromethylene group) and -[OCF ２ CF ２ It is preferable to use a group having both the repeating unit: -[OCF ]-(oxyperfluoroethylene group). ２ ]-と-[OCF ２ CF ２ ]- and in a molar ratio of [repeating unit: -[OCF ２ ]-]: [Repeating unit: −[OCF ２ CF ２

[0033] Preferably, it is a group containing the repeating units in a ratio of 1:1 to 2:1, more preferably a group containing the repeating units in a ratio of approximately 1:1. The bonding of these repeating units may be either block bonding or random bonding. The total 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. The weight average molecular weight (Mw) of the poly(oxyperfluoroalkylene) group measured in polystyrene equivalent by gel permeation chromatography is 1,000 to 5,000, preferably 1,500 to 3,000.

[0021] In the present invention, as component (b), a perfluoropolyether containing a poly(oxyperfluoroalkylene) group can be used, which has an active energy ray polymerizable group at the end of its molecular chain via a urethane bond (hereinafter simply referred to as "perfluoropolyether having a polymerizable group at the end of its molecular chain"). The end of the molecular chain of the perfluoropolyether can be either all or some of the ends of the molecular chain. When the molecular chain of the perfluoropolyether is linear, all or some of the ends of the molecular chain can be both ends and one end of the linear molecular chain, respectively. The perfluoropolyether having a polymerizable group at the end of the molecular chain can exclude perfluoropolyethers having a poly(oxyalkylene) group between the poly(oxyperfluoroalkylene) group and the urethane bond. In addition, the perfluoropolyether having a polymerizable group at the end of the molecular chain has excellent compatibility with component (a), which prevents the hard coat layer from becoming cloudy, allowing the formation of a hard coat layer with a transparent appearance.

[0022] Examples of the active energy ray polymerizable group include a (meth)acryloyl group and a vinyl group.

[0023] The perfluoropolyether having a polymerizable group at the end of the molecular chain is not limited to one having one active energy ray-polymerizable group at the end of the molecular chain, but may be one having two or more active energy ray-polymerizable groups at the end of the molecular chain. For example, examples of terminal structures containing an active energy ray-polymerizable group include structures of the following formulae [A1] to [A5], and structures in which the acryloyl group in these structures is substituted with a methacryloyl group.

[0024]

[0025] An example of such perfluoropolyether having a polymerizable group at the end of the molecular chain is a compound represented by the following formula [2]: (In formula [2], A represents one of the structures represented by formulas [A1] to [A5] and structures in which an acryloyl group in these structures is substituted with a methacryloyl group, and PFPE represents the poly(oxyperfluoroalkylene) group (wherein L １ The side directly bonded to is an oxy end, and the side bonded to the oxygen atom is a perfluoroalkylene end. １ represents an alkylene group having 2 or 3 carbon atoms substituted with 1 to 3 fluorine atoms, each m independently represents an integer of 1 to 5, L ２ represents an (m+1)-valent residue obtained by removing OH from an (m+1)-valent alcohol.

[0026] The alkylene group having 2 or 3 carbon atoms and substituted with 1 to 3 fluorine atoms includes —CH ２ CHF-, -CH ２ CF ２ -, -CHFCF ２ -, -CH ２ CH ２ CHF-, -CH ２ CH ２ CF ２ -, -CH ２ CHFCF ２ -, etc., -CH ２ CF ２ - is preferred.

[0027] Partial structure (A-NHC(=O)O) in the compound represented by the above formula [2] ｍ L ２ Examples of - include structures represented by the following formulas [B1] to [B12]. (In formulas [B1] to [B12], A represents one of the structures represented by formulas [A1] to [A5] and structures in which an acryloyl group in these structures is substituted with a methacryloyl group.) Among the structures represented by formulas [B1] to [B12], formulas [B1] and [B2] correspond to the case where m = 1, formulas [B3] to [B6] correspond to the case where m = 2, formulas [B7] to [B9] correspond to the case where m = 3, and formulas [B10] to [B12] correspond to the case where m = 5. Of these, the structure represented by formula [B3] is preferred, and the combination of formula [B3] and formula [A3] is particularly preferred.

[0028] Among the perfluoropolyethers having a polymerizable group at the end of the molecular chain, particularly preferred are compounds having a partial structure represented by the following formula [1]: The partial structure represented by formula [1] corresponds to the portion of the compound represented by formula [2] excluding A-NHC(=O). n in formula [1] represents the repeating unit -[OCF ２ CF ２ ]- and the number of repeating units -[OCF ２ ]-, 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 ]- and the number of repeating units -[OCF 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 bonding of these repeating units may be either block bonding or random bonding.

[0029] In the present invention, the perfluoropolyether having a polymerizable group at the molecular chain end is used in a proportion of 0.05 to 10 parts by mass, preferably 0.1 to 5 parts by mass, and more preferably 0.1 to 1 part by mass, per 100 parts by mass of the (a) polyfunctional (meth)acrylate monomer. By using 0.05 parts by mass or more of the perfluoropolyether having a polymerizable group at the molecular chain end, sufficient stain resistance, scratch resistance, and chemical resistance can be imparted to the hard coat layer. Furthermore, by using 10 parts by mass or less of the perfluoropolyether having a polymerizable group at the molecular chain end, sufficient compatibility with the (a) polyfunctional (meth)acrylate monomer can be achieved, resulting in a hard coat layer with less opacity.

[0030] The perfluoropolyether having a polymerizable group at the end of the molecular chain is, for example, a perfluoropolyether represented by the following formula [3]: (In formula [3], PFPE, L １ , L ２ and m have the same meaning as in the formula [2] above.) with an isocyanate compound having a polymerizable group, that is, a compound in which an isocyanato group is bonded to a bond in the structure represented by the formulas [A1] to [A5] above or in a structure in which the acryloyl group in these structures is substituted with a methacryloyl group (for example, 2-(meth)acryloyloxyethyl isocyanate, 1,1-bis((meth)acryloyloxymethyl)ethyl isocyanate, etc.), to form a urethane bond.

[0031] In addition, the perfluoropolyether containing poly (oxyperfluoroalkylene) group, which is a specific example of the (b) component: surface modifier in the curable composition of the present invention, is a perfluoropolyether containing poly (oxyperfluoroalkylene) group, and has an active energy ray polymerizable group at one end (one end) of its molecular chain via a urethane bond, and has a hydroxyl group at the other end (other end) of its molecular chain, or a perfluoropolyether containing poly (oxyperfluoroalkylene) group as represented by the above formula [3], and has a hydroxyl group at both ends of its molecular chain [compound that does not have an active energy ray polymerizable group].It is possible to add the condition that there is no poly (oxyalkylene) group between the poly (oxyperfluoroalkylene) group and the urethane bond, and between the poly (oxyperfluoroalkylene) group and the hydroxyl group.

[0032] [(c) Polymerization Initiator] Examples of polymerization initiators used in the curable composition of the present invention include polymerization initiators that generate radicals when irradiated with active energy rays such as electron beams, ultraviolet rays, and X-rays, particularly ultraviolet rays. Examples of the (c) polymerization initiator include benzoins, alkylphenones, thioxanthones, azo compounds, azides, diazo compounds, o-quinonediazides, 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 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 (c) polymerization initiator. The use of alkylphenones makes it possible to obtain a cured film with improved scratch resistance.

[0033] 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.

[0034] In the present invention, the (c) polymerization initiator is used in a proportion of 1 to 20 parts by mass, preferably 1 to 10 parts by mass, and more preferably 1 to 5 parts by mass, per 100 parts by mass of the (a) polyfunctional (meth)acrylate monomer.

[0035] [(d) Solvent] The curable composition of the present invention contains a (d) solvent, i.e., it can be used in the form of a varnish (film-forming material). In the curable composition of the present invention, the (d) solvent is characterized in that it essentially contains a (d1) solvent having a normal boiling point of more than 150°C and not more than 205°C (hereinafter also referred to as a (d1) solvent). This promotes the migration of the (b) surface modifier to the surface of the cured film when the curable composition is used to form a cured film (during curing), and is expected to improve chemical resistance in particular.

[0036] The (d1) solvent having a normal boiling point of more than 150°C and not more than 205°C is, for example, selected from the group consisting of propylene glycol monobutyl ether (170°C), diethylene glycol ethyl methyl ether (176°C), γ-butyrolactone (204°C), 3-methoxy-1-butanol (158°C), propylene glycol (188°C), and hexylene glycol (196°C). These may be used alone or in combination of two or more. Other examples of the (d1) solvent include diacetone alcohol (166°C), acetonylacetone (192°C), methyl acetoacetate (180°C), ethyl acetoacetate (180°C), ethyl lactate (154°C), 1,2-butanediol (192°C), 1,2-ethanediol (ethylene glycol) (197°C), tetralin (208°C), o-dichlorobenzene (180°C), 3-methoxybutyl acetate (171°C), ethyl cellosolve acetate (156°C), ethyl cellosolve (197°C), butyl cellosolve (171°C), di-n-butyl ketone (186°C), cyclohexanone (155°C), 2-ethylhexyl alcohol (184°C), benzyl alcohol Coal (205°C), N,N-dimethylformamide (DMF) (153°C), N,N-dimethylacetamide (DMAc) (165°C), N-methyl-2-pyrrolidone (NMP) (202°C), dimethyl sulfoxide (DMSO) (189°C), cyclohexyl acetate (172°C), propylene glycol diacetate (191°C), ethylene glycol monobutyl ether acetate (192°C), diethylene glycol monoethyl ether (202°C), dipropylene glycol monomethyl ether (190°C), dipropylene glycol dimethyl ether (175°C), dipropylene glycol methyl propyl ether (203°C), and the like can also be used.

[0037] Furthermore, in the present invention, in addition to the solvent (d1), the composition may further contain a solvent (d2) having a normal boiling point of 150° C. or less (hereinafter also referred to as solvent (d2)). The solvent (d2) is compatible with the solvent (d1), and can dissolve and disperse the components (a) to (c), the conductive polymer material (e) described below, if desired, and other additives. The solvent (d2) can be selected in consideration of the workability during application for forming a cured film (hard coat layer) described below, drying properties before and after curing, and the like. For example, water; aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; 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, and perchloroethylene; esters or ester ethers such as ethyl acetate, propyl acetate, butyl acetate, methyl 2-hydroxyisobutyrate, methyl cellosolve acetate, and propylene glycol monomethyl ether acetate (PGMEA); diethyl ether, tetrahydrofuran (THF), 1, Examples of suitable solvents include ethers such as 4-dioxane, methyl cellosolve, propylene glycol monomethyl ether (PGME), propylene glycol monoethyl ether (PGEE), propylene glycol mono-n-propyl ether, and propylene glycol monoisopropyl ether; ketones such as acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), and cyclopentanone; alcohols such as methanol, ethanol, n-propanol, isopropyl alcohol, n-butanol, isobutyl alcohol, and tert-butyl alcohol; and mixtures of two or more of these solvents.

[0038] In the curable composition of the present invention, the (d1) solvent having a standard boiling point of greater than 150°C and equal to or less than 205°C is contained in an amount of 10 to 150 parts by mass relative to 100 parts by mass of the (a) polyfunctional (meth)acrylate monomer, and is contained in an amount of 4 to 50 parts by mass relative to 100 parts by mass of the curable composition for forming a hard coat layer. Furthermore, the (d) solvents (the sum of (d1) solvents having a standard boiling point of greater than 150°C and equal to or less than 205°C and (d2) solvents having a standard boiling point of equal to or less than 150°C) are used in a concentration such that the solids concentration in the curable composition of the present invention is, for example, 1% to 70% by mass, preferably 5% to 50% by mass. Here, the solids concentration (also referred to as non-volatile content concentration) refers to the content of the solids (all components excluding the solvent component) relative to the total mass (total mass) of the (a) to (c) components (and, if desired, the (e) component described below and other additives) of the curable composition of the present invention.

[0039] (e) Conductive Polymer Material The curable composition of the present invention may also contain (e) a conductive polymer material, which has excellent charge transport properties and can thereby impart antistatic properties to the hard coat layer.

[0040] The (e) conductive polymer material is not particularly limited, but examples thereof include polymers containing repeating units derived from thiophene, carbazole, phenylene, vinylene, acetylene, aniline, phenylenediamine, and pyrrole monomers, viologen derivatives, phenothiazine, and tetrathiafulvalene, and these may be used alone or in combination of two or more.

[0041] More specifically, examples of the conductive polymer include polythiophene-based polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonic acid) (PEDOT-PSS), polyacetylene-based polymers, polyaniline-based polymers, and polypyrrole-based polymers.

[0042] In the present invention, when the conductive polymer material (e) is contained, the conductive polymer material can be contained in an amount of 0.1 to 20 parts by mass, preferably 1 to 10 parts by mass, relative to 100 parts by mass of the polyfunctional (meth)acrylate monomer (a). The conductive polymer material (e) can be blended in the form of a dispersion containing the conductive polymer material, for example, in the form of an aqueous dispersion, into the curable composition of the present invention.

[0043] [Other Additives] Furthermore, the curable composition of the present invention may contain, as needed, one or more of the following additives that are commonly added as needed, as long as they do not impair the effects of the present invention: polymerization accelerators, polymerization inhibitors, photosensitizers, leveling agents, surfactants, adhesion promoters, plasticizers, UV absorbers, light stabilizers, antioxidants, storage stabilizers, antistatic agents, inorganic fillers, pigments, dyes, etc., either alone or in combination. It is preferable that the curable composition of the present invention does not contain inorganic particles or organic particles. However, even in embodiments that do not contain these inorganic particles or organic particles, it is acceptable for these particles to be present at the impurity level.

[0044] <Cured Film (Hard Coat Layer)> The curable composition of the present invention can be applied (coated) onto a substrate to form a coating film, and then irradiated with active energy rays to polymerize (cure) the coating film, thereby forming a cured film. Furthermore, the hard coat layer in the hard coat film described below can be made of the cured film. In this case, examples of the substrate include various resins (polyesters such as polycarbonate, polymethacrylate, polystyrene, 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), polyvinyl chloride (PVC), polypropylene (PP), norbornene-based resin, etc.), metal, wood, paper, glass, and slate. The shape of these substrates may be a plate, a film, or a three-dimensional molded object.

[0045] The method for applying the composition to the substrate can be appropriately selected from, for example, cast coating, spin coating, blade coating, dip coating, roll coating, spray coating, bar coating, die coating, inkjet printing, and printing methods (such as relief printing, intaglio printing, lithographic printing, and screen printing). Among these methods, a roll-to-roll method can be used. From the viewpoint of thin-film coating properties, relief printing, particularly gravure coating, is preferred. It is preferable to filter the curable composition of the present invention before application using a filter having a pore size of approximately 0.2 μm or the like. If necessary, a solvent may be added to the curable composition of the present invention during application. As the solvent, the various solvents listed above under [(d) Solvent] can be used. After applying the curable composition of the present invention to a substrate to form a coating film, the coating film is pre-dried, if necessary, using a heating means such as a hot plate or oven to remove the solvent (solvent removal step). The heat drying conditions are preferably, for example, 40°C to 120°C and 30 seconds to 10 minutes. After drying, the coating film is cured by irradiating it 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. 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. The polymerization may then be completed by post-baking, specifically by heating using a heating means such as a hot plate or oven. The thickness of the cured film formed after drying and curing can typically be 0.01 μm to 50 μm, for example, 0.05 μm to 20 μm, preferably 1 μm to 20 μm, and more preferably 3 μm to 15 μm.

[0046] <Hard Coat Film> Using the curable composition of the present invention, a hard coat film having a hard coat layer on at least one side (surface) of a film substrate can be produced. The hard coat film is also within the scope 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.

[0047] The hard coat layer in the hard coat film of the present invention can be formed by a method including the steps of applying the above-described curable composition of the present invention onto a film substrate to form a coating film, and irradiating the coating film with active energy rays such as ultraviolet rays to cure the coating film.

[0048] The film substrate may be any of the various transparent resin films usable for optical applications, selected from the substrates listed in the above section <Cured Film (Hard Coat Layer)>. Preferred resin films include, for example, polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene naphthalate (PEN), polyurethanes, thermoplastic polyurethanes (TPU), polycarbonates, polymethacrylates, polystyrenes, polyolefins, polyamides, polyimides, triacetyl cellulose (TAC), acrylonitrile-butadiene-styrene copolymers (ABS), acrylonitrile-styrene copolymers (AS), polyvinyl chloride (PVC), and polypropylene (PP). The method for applying the curable composition to the film substrate (coating film forming step) and the method for irradiating the coating film with active energy rays (curing step) can be the same as those listed in the above section <Cured Film (Hard Coat Layer)>. After the coating film forming step, a step of drying the coating film to remove the solvent may be included, if necessary. In this case, the coating drying method (solvent removal step) described above in <Cured Film (Hard Coat Layer)> can be used. The thickness (film thickness) of the hard coat layer thus obtained can be, for example, 0.01 μm to 100 μm, or 0.01 μm to 50 μm, or 0.05 μm to 20 μm, or 0.1 μm to 20 μm, etc.

[0049] The hard coat film of the present invention can be used as a hard coat film for displays and polarizing plates, and displays and polarizing plates provided with the hard coat film are also within the scope of the present invention.

[0050] 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 sample preparation and physical property analysis are as follows.

[0051] (1) Coating by bar coater Apparatus: Automatic Film Applicator AB3125 manufactured by TQC Sheen Co., Ltd. Bar: A-Bar OSP-25 manufactured by OSG System Products Co., Ltd., maximum wet film thickness 25 μm (equivalent to wire bar #10) Bar: A-Bar OSP-35 manufactured by OSG System Products Co., Ltd., maximum wet film thickness 35 μm (equivalent to wire bar #14) Coating speed: 4 m / min (2) Oven Apparatus: Two-layer clean oven (top and bottom type) PO-250-45-D manufactured by Sanki Keiso Co., Ltd. (3) UV curing Apparatus: CV-110QC-G manufactured by Heraeus Co., Ltd. Lamp: Electrodeless lamp H-bulb manufactured by Heraeus Co., Ltd. (4) Gel permeation chromatography (GPC) Apparatus: HLC-8420GPC manufactured by Tosoh Corporation Column: TSKgel (registered trademark) G2000HXL, G3000HXL manufactured by Tosoh Corporation Column temperature: 40°C Eluent: Tetrahydrofuran Detector: UV (5) Abrasion resistance test Apparatus: Reciprocating abrasion tester TRIBOGEAR TYPE: 30H manufactured by Shinto Scientific Co., Ltd. Scanning speed: 0.5 m / min Scanning distance: 15 mm (6) Contact angle measurement Apparatus: DropMaster DM-501 manufactured by Kyowa Interface Science Co., Ltd. Measurement temperature: 23°C Solvent: Water, methylene iodide

[0052] The abbreviations have the following meanings: Ac1: polyfunctional acrylate [Aronix (registered trademark) MT-3010, manufactured by Toagosei Co., Ltd.] C1: PEDOT / PSS aqueous dispersion [PEDOT (poly(3,4-ethylenedioxythiophene) / PSS (polystyrene sulfonic acid) 3.0 mass % to 4.0 mass % aqueous dispersion, high conductivity grade, product number 655201, manufactured by Sigma-Aldrich] PFPE1: perfluoropolyether having the following structure, which has two hydroxy groups at each end of a molecular chain containing a poly(oxyperfluoroalkylene) group, without a poly(oxyalkylene) group interposed therebetween [Fomblin (registered trademark) T4, manufactured by Solvay Specialty Polymers] １９ F-NMR and １ Number average molecular weight calculated from H-NMR analysis results: 2200 (In the above formula, m represents the repeating unit -(CF ２ CF ２ O)-, and n is the number of repeating units -(CF ２ The number of repeating units (m+n)- satisfies 5≦(m+n)≦40, and m and n each independently represent an integer of 0 or more. When both repeating units are present, these repeating units are bonded by block bonds, random bonds, or block bonds and random bonds. ) BEI: 1,1-bis(acryloyloxymethyl)ethyl isocyanate [Karenz (registered trademark) BEI, manufactured by Resonac Corporation] DOTDD: dioctyltin dineodecanoate [Neostan (registered trademark) U-830, manufactured by Nitto Kasei Co., Ltd.] O2959: 2-hydroxy-1-(4-(2-hydroxyethoxy)phenyl)-2-methylpropan-1-one [Omnirad (registered trademark) 2959, manufactured by IGM Resins] PB: propylene glycol monobutyl ether HBM: methyl 2-hydroxyisobutyrate PGME: propylene glycol monomethyl ether PGMEA: propylene glycol monomethyl ether acetate EDM: diethylene glycol ethyl methyl ether GBL: γ-butyrolactone MB: 3-methoxy-1-butanol PG: propylene glycol HG: Hexylene glycol IPA: Isopropyl alcohol

[0053] [Production Example 1] Production of perfluoropolyether (S1) having four acryloyl groups via urethane bonds at each end of a molecular chain containing a poly(oxyperfluoroalkylene) group. 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 charged into a screw tube. This mixture was stirred at room temperature (approximately 23 ° C.) for 24 hours using a stirrer tip to obtain a 50 wt% PGMEA solution of the target compound S1. The weight average molecular weight (Mw) of the obtained S1 measured in polystyrene equivalent by GPC was 2,300, and the dispersity (Mw (weight average molecular weight) / Mn (number average molecular weight)) was 1.0.

[0054] [Examples 1 to 8, Comparative Examples 1 to 5] The following components listed in Table 1 were mixed to prepare curable compositions having the solid content concentrations listed in Table 1. Here, the solid content refers to components other than the solvent. In Table 1, [parts] represents [parts by mass] and [%] represents [% by mass]. Polyfunctional (meth)acrylate monomer: 100 parts by mass of the polyfunctional (meth)acrylate monomer listed in Table 1. Surface modifier: 0.8 parts by mass of a 50% by mass PGMEA solution of S1 (S1 solid content 0.4 parts by mass, solvent 3: PGMEA 0.4 parts by mass). Polymerization initiator: 2.5 parts by mass of O2959. Conductive polymer material: The conductive polymer material listed in Table 1 (as a 3.0% to 4.0% by mass aqueous dispersion) was used in the amount listed in Table 1. Solvent: The solvent listed in Table 1 was used in the amount listed in Table 1.

[0055]

[0056] The curable composition was applied with a bar coater onto an A4-sized PET film [Lumirror (registered trademark) U403 (also known as U40) manufactured by Toray Industries, Inc., thickness 50 μm] on both sides of which a primer layer had been formed by easy-adhesion treatment, to obtain a coating film. The bar coater used was OSP-25 in Example 1 and Comparative Examples 1 to 4, which had a solids concentration of 20%, and OPS-35 in Examples 2 to 8 and Comparative Example 5, which had a solids concentration of 30%. The 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 an exposure dose of 700 mJ / cm under a nitrogen atmosphere.２ The film was exposed to UV light of 1000 kJ / cm 2 , thereby producing a hard coat film having a hard coat layer (cured film) with a thickness of approximately 5 μm.

[0057] The homogeneity of the curable composition, and the water repellency and chemical resistance of the resulting hard coat film having a hard coat layer were evaluated. The procedures for evaluating the homogeneity, water repellency, and chemical resistance of the cured composition are shown below. The results are also shown in Table 2.

[0058] [Composition Homogeneity] Immediately after preparation, the appearance of each curable composition was visually inspected and evaluated according to the following criteria. A: Transparent solution (no floating matter, sediment, or phase separation) C: Presence of floating matter, sediment, or phase separation [Water Repellency] 3 μL of water was applied to the surface of the hard coat layer, and the contact angle θ was measured five times after 5 seconds. The average value was used to evaluate the water repellency according to the following criteria: A: θ > 105 degrees B: 100 degrees ≦ θ ≦ 105 degrees C: θ < 100 degrees [Chemical Resistance] Ethanol was dropped onto the surface of the hard coat layer, and then a cylindrical eraser [Minoan Rubber Stick, φ6.0 mm] attached to the reciprocating abrasion tester was rubbed 4,000 times with a load of 1 kg. 3 μL of water was applied to the rubbed area, and the contact angle θ was measured five times after 5 seconds. The average value was used to evaluate the water repellency according to the following criteria. A: θ>95 degrees B: 90 degrees≦θ≦95 degrees C: θ<90 degrees

[0059]

[0060] As shown in Table 2, the hard coat layers of Examples 1 and 2 to 8 obtained using a curable composition containing a solvent having a normal boiling point of 158°C or higher had a water contact angle of more than 95° after the surface chemical resistance test, and it was revealed that they had superior chemical resistance compared to the hard coat layers (Comparative Examples 1 to 5) obtained using a curable composition whose solvent component was composed only of a solvent having a normal boiling point of 146°C or lower.

Claims

1. A curable composition for forming a hard coat layer, comprising: (a) a polyfunctional (meth)acrylate monomer; (b) a surface modifier; (c) a polymerization initiator; and (d) a solvent, wherein the (d) solvent comprises (d1) a solvent having a standard boiling point of greater than 150°C and not greater than 205°C, and the (d1) solvent having a standard boiling point of greater than 150°C and not greater than 205°C is contained in an amount of 10 to 150 parts by mass per 100 parts by mass of the (a) polyfunctional (meth)acrylate monomer, and 4 to 50 parts by mass per 100 parts by mass of the curable composition for forming a hard coat layer.

2. The curable composition for forming a hard coat layer according to claim 1, wherein the solvent (d) further contains a solvent (d2) having a normal boiling point of 150°C or less.

3. The curable composition for forming a hard coat layer according to claim 1 or 2, wherein the (d1) solvent having a standard boiling point of more than 150°C and not more than 205°C is selected from the group consisting of propylene glycol monobutyl ether, diethylene glycol ethyl methyl ether, γ-butyrolactone, 3-methoxy-1-butanol, propylene glycol, and hexylene glycol.

4. The curable composition for forming a hard coat layer according to claim 1 or 2, which does not contain inorganic particles or organic particles.

5. The curable composition for forming a hard coat layer according to claim 1 or 2, further comprising (e) a conductive polymer material.

6. The composition for forming a hard coat layer according to claim 1 or 2, wherein the (b) surface modifier is a perfluoropolyether containing a poly(oxyperfluoroalkylene) group represented by the following formula [2], and the composition contains 0.05 to 10 parts by mass of the perfluoropolyether containing a poly(oxyperfluoroalkylene) group per 100 parts by mass of the (a) polyfunctional (meth)acrylate monomer. (In formula [2], A represents a structure represented by the following formula [A3] or a structure in which the acryloyl group in the structure is substituted with a methacryloyl group, and PFPE represents the poly(oxyperfluoroalkylene) group (wherein L １ The side directly bonded to is an oxy end, and the side bonded to the oxygen atom is a perfluoroalkylene end. １ represents an alkylene group having 2 or 3 carbon atoms substituted with 1 to 3 fluorine atoms, each m independently represents an integer of 1 to 5, and the partial structure (A-NHC(═O)O) ｍ L ２ - represents a structure represented by the following formula [B3].

7. A hard-coated film having a hard-coat layer on at least one surface of a film substrate, the hard-coat layer being a cured product of the hard-coat layer-forming curable composition according to claim 1 or 2.

8. A display device equipped with the hard coat film according to claim 7.

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