Urethane (meth)acrylate resin, active energy ray curable composition, cured coating film, and hard coat film

Abstract

The present invention provides a urethane (meth)acrylate resin capable of forming a cured coating film with high coating hardness and excellent curl resistance, an active energy ray curable composition containing the same, a cured coating film, and a hard coat film. [Solution] A urethane (meth)acrylate resin which is a reaction product of an isocyanate compound (A), an isocyanurate ethylene oxide modified (meth)acrylate compound (B), and a polyfunctional (meth)acrylate compound (C) having a hydroxyl group.

Description

[Technical Field]

[0001] The present invention relates to a urethane (meth)acrylate resin, an active energy ray curable composition containing the same, a cured coating film, and a hard coat film. [Background technology]

[0002] Plastic films manufactured using polyethylene terephthalate resin (PET), acrylic resin, polycarbonate resin, acetylated cellulose resin, etc., are widely used in industrial applications such as polarizing plate protective films incorporated inside flat panel displays and surface protective films for touch panels. These plastic films alone have shortcomings in performance, such as being easily scratched, having poor processability, and being prone to cracking and fissures. Therefore, they are usually used with a hard coat layer made of an active energy ray curable composition or the like applied to the surface to compensate for these performance issues.

[0003] Hard coat layers used in optical films require high hardness to provide scratch resistance. Generally, it is known that the hardness of the hard coat layer can be increased by improving the crosslinking density using polyfunctional monomers (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2019-006897 [Overview of the project] [Problems that the invention aims to solve]

[0005] However, resin compositions with improved crosslinking density, such as those described in Patent Document 1, exhibit high coating hardness and excellent scratch resistance, but they also tend to experience significant curing shrinkage in the hard coat layer, causing the resin film to warp strongly on all four sides. Excessive warping (curling) of the cured resin film can lead to problems such as reduced yield during manufacturing. Furthermore, excessive curling can make processing difficult when laminating circular polarizing plates to the hard coat layer.

[0006] Therefore, there was a need for a material that could form a cured coating film with high coating hardness and excellent curl resistance.

[0007] The present invention was made to solve the above-mentioned problems, and aims to provide a urethane (meth)acrylate resin capable of forming a cured coating film having high coating hardness and excellent curl resistance, an active energy ray curable composition containing the same, a cured coating film, and a hard coat film. [Means for solving the problem]

[0008] As a result of diligent research to solve the above problems, the present inventors have found that by mainly including an isocyanurate ethylene oxide modified (meth)acrylate compound (B), a urethane (meth)acrylate resin capable of forming a cured coating film with high coating hardness and excellent curl resistance can be obtained, and have completed the present invention.

[0009] In other words, the present invention encompasses the following embodiments. [1] A urethane (meth)acrylate resin which is a reaction product of an isocyanate compound (A), an ethylene oxide isocyanurate-modified (meth)acrylate compound (B), and a polyfunctional (meth)acrylate compound having a hydroxyl group (C). [2] The urethane (meth)acrylate resin according to [1], wherein the isocyanate compound (A) is at least one compound selected from the group consisting of isocyanurate group-containing polyisocyanates, aliphatic isocyanates, aromatic isocyanates, and alicyclic structure-containing isocyanates. [3] The urethane (meth)acrylate resin according to [1] or [2], wherein the isocyanurate ethylene oxide modified (meth)acrylate compound (B) is a compound represented by the following formula (1). [ka] [In formula (I), R 1 This represents a hydrogen atom or -COCH=CH2. [4] The urethane (meth)acrylate resin according to any one of [1] to [3], wherein the polyfunctional (meth)acrylate compound (C) is at least one compound selected from the group consisting of glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, 2-hydroxy-3-methacrylpropyl(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. [5] The urethane (meth)acrylate resin according to any one of [1] to [4], wherein the (meth)acrylic group concentration of the urethane (meth)acrylate resin is 4.0 to 8.0 mmol / g. [6] The urethane (meth)acrylate resin according to any one of [1] to [5], wherein the urethane bond concentration of the urethane (meth)acrylate resin is 1.0 to 3.0 mmol / g. An active energy ray curable composition containing a urethane (meth)acrylate resin as described in any of [7][1] to [6] and a photopolymerization initiator. A cured coating film which is a cured reaction product of the active energy ray curable composition described in [8][7]. A hard coat film comprising the cured coating film and substrate described in [9][8]. [Modes for carrying out the invention]

[0010] The following describes in detail the urethane (meth)acrylate resin, active energy ray curable composition, cured coating film, and hard coat film of the present invention. However, the description of the constituent elements described below is an example (representative example) of one embodiment of the present invention and is not limited to these contents.

[0011] In the following explanation, "(meth)acryloyl" means acryloyl and / or methacryloyl. "(meth)acrylate" means acrylate and / or methacrylate. Furthermore, "(meth)acrylic" means acrylic and / or methacrylic.

[0012] (Urethane (meth)acrylate resin) The urethane (meth)acrylate resin of the present invention is a reaction product obtained by reacting an isocyanate compound (A), an ethylene oxide isocyanurate-modified (meth)acrylate compound (B), and a polyfunctional (meth)acrylate compound having a hydroxyl group (C). To our surprise, the inventors have discovered that a urethane (meth)acrylate resin having the above configuration can form a cured coating film that has high coating hardness and excellent curl resistance.

[0013] The mechanism by which the above effects are achieved by the configuration of the present invention is presumed to be as follows.

[0014] As described above, generally, in order to improve the hardness of a coating film, it is important to use a polyfunctional monomer and increase the number of crosslinking points. In the above Patent Document 1, it is described that a polyfunctional monomer is used to improve the hardness of a coating film. In contrast, the urethane (meth)acrylate resin of the present invention uses an ethylene oxide-modified isocyanuric acid (meth)acrylate compound (B) together with a polyfunctional monomer. Here, since the ethylene oxide-modified isocyanuric acid (meth)acrylate compound (B) has a low double bond concentration, it is considered that the crosslinking density becomes low in the curing process. As a result, it is presumed that when the ethylene oxide-modified isocyanuric acid (meth)acrylate compound (B) is used together with a polyfunctional monomer, a urethane (meth)acrylate resin capable of forming a cured coating film excellent in curl resistance can be obtained as compared with the case where only a polyfunctional monomer is used.

[0015] On the other hand, in a cured coating film, a tendency is observed that the hardness of the coating film decreases along with the decrease in curl. Here, since the ethylene oxide-modified isocyanuric acid (meth)acrylate compound (B) has a cyclic structure of isocyanuric acid, it is considered that when an external impact is applied to the cured coating film, the external impact is absorbed by the cyclic structure. As a result, it is presumed that when the ethylene oxide-modified isocyanuric acid (meth)acrylate compound (B) is used together with a polyfunctional monomer, a urethane (meth)acrylate resin capable of forming a cured coating film excellent in curl resistance while maintaining a high coating film hardness can be obtained.

[0016] Therefore, the present invention can provide a urethane (meth)acrylate resin capable of forming a cured coating film having a high coating film hardness and excellent in curl resistance, an active energy ray-curable composition containing the same, a cured coating film, and a hard coat film.

[0017] <Isocyanate compound (A)> The isocyanate compound (A) is a compound having at least one isocyanate group in the molecule. The isocyanate compound (A) used in the present invention is preferably at least one compound selected from the group consisting of isocyanurate group-containing polyisocyanates, aliphatic isocyanates, aromatic isocyanates, and alicyclic structure-containing isocyanates. These isocyanate compounds (A) can be used alone or in combination of two or more. Modified forms of these isocyanate compounds (A), such as isocyanurate modified forms, biuret modified forms, and allophanate modified forms, can also be used.

[0018] Isocyanurate group-containing polyisocyanates are compounds having at least one isocyanurate group and two or more isocyanate groups in their molecule. Generally, isocyanurate group-containing polyisocyanates are obtained by polymerizing and trimerizing a polyisocyanate compound in the presence of a catalyst. The polyisocyanate compound used for polymerization is a compound having two or more isocyanate groups in its molecule, and may be an isocyanate compound included in aliphatic isocyanates, aromatic isocyanates, and alicyclic structure-containing isocyanates, or a mixture thereof. Examples of catalysts include phosphines, phospholine derivatives, amine alkali salts, metal compounds, and Mannich bases.

[0019] Examples of aliphatic isocyanates include ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate, 1,6,11-undecane triisocyanate, 1,3,6-hexamethylene triisocyanate, xylylene diisocyanate (XDI), tetramethylxylylene diisocyanate (TMXDI), and trimethylhexamethylene diisocyanate.

[0020] Examples of aromatic isocyanates include phenylenediisocyanate, 2,4-tolylenediisosoanate, 2,6-tolylenediisocyanate, 2,2'-diphenylmethanediisocyanate, 4,4'-diphenylmethanediisocyanate, 4,4'-toluidinediisocyanate, 4,4'-diphenyletherdiisocyanate, 4,4'-diphenyldiisocyanate, 1,5-naphthalenediisocyanate, xylylenediisocyanate, methylenebis-4-phenylisocyanate, and p-phenylenediisocyanate.

[0021] Examples of isocyanates containing alicyclic structures include 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-bisisocyanatomethylcyclohexane, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, and hydrogenated tetramethylxylylene diisocyanate.

[0022] Commercially available isocyanate compound (A) can be used. Examples of commercially available isocyanate compound (A) include "Duranate 24A-100" and "Duranate 50M-HDI" from Asahi Kasei Corporation, "Barnock D800," "Barnock DN980," and "DN902S" from DIC Corporation, and "Takenate® 500" and "Takenate® 600" from Mitsui Chemicals, Inc.

[0023] <Isocyanurate ethylene oxide modified (meth)acrylate compound (B)> The isocyanurate ethylene oxide modified (meth)acrylate compound (B) used in the present invention is preferably an isocyanurate ethylene oxide modified di or tri(meth)acrylate represented by the following general formula (I).

[0024] [ka] [In formula (I), R 1 This represents a hydrogen atom or -COCH=CH2.

[0025] These isocyanurate ethylene oxide-modified (meth)acrylate compounds (B) can be used alone or in combination of two or more.

[0026] Commercially available isocyanurate ethylene oxide-modified (meth)acrylate compound (B) can be used. Examples of commercially available isocyanurate ethylene oxide-modified diacrylate include "Aronics® M-215" manufactured by Toagosei Co., Ltd. Examples of mixtures of isocyanurate ethylene oxide-modified diacrylate and isocyanurate ethylene oxide-modified triacrylate include "Aronics® M-313" (30-40% by weight) and "Aronics® M-315" (3-13% by weight) manufactured by Toagosei Co., Ltd. Note that the percentages in parentheses above are catalog values ​​for the content of isocyanurate ethylene oxide-modified diacrylate in the mixture.

[0027] The amount of isocyanurate ethylene oxide modified (meth)acrylate compound (B) is not particularly limited, but it is preferably 20% by mass or more, and more preferably 30% by mass or more, based on the total 100% by mass (solid content ratio) of the reaction raw materials (A) to (C). Furthermore, the above amount is preferably 80% by mass or less, and more preferably 70% by mass or less. When the above amount is within the above range, it is easy to obtain a urethane (meth)acrylate resin that can form a cured coating film with high coating hardness and excellent curl resistance.

[0028] <Polyfunctional (meth)acrylate compound (C) containing a hydroxyl group> A polyfunctional (meth)acrylate compound (C) having hydroxyl groups is a compound having one or more hydroxyl groups and two or more (meth)acryloyl groups in its molecule. In the curing reaction when obtaining a cured coating film, the polyfunctional (meth)acrylate (C) having hydroxyl groups involves multiple (meth)acryloyl groups, forming a good crosslinked structure and enabling good physical properties such as surface hardness and scratch resistance. A polyfunctional (meth)acrylate compound (C) having hydroxyl groups can be used alone or in combination of two or more types.

[0029] Polyfunctional (meth)acrylate compounds (C) having hydroxyl groups include, for example, mono(meth)acrylates of dihydric alcohols such as ethylene glycol mono(meth)acrylate, propylene glycol mono(meth)acrylate, butanediol mono(meth)acrylate, pentanediol mono(meth)acrylate, hexanediol mono(meth)acrylate, diethylene glycol mono(meth)acrylate, dipropylene glycol mono(meth)acrylate, triethylene glycol mono(meth)acrylate, tripropylene glycol mono(meth)acrylate, tetraethylene glycol mono(meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth)acrylate, neopentyl glycol mono(meth)acrylate, ethoxylated neopentyl glycol mono(meth)acrylate, hydroxypivalate neopentyl glycol mono(meth)acrylate, and 2-hydroxy-3-methacrylpropyl(meth)acrylate;

[0030] Monoacrylates or di(meth)acrylates of trivalent alcohols such as trimethylolpropane mono(meth)acrylate, ethoxylated trimethylolpropane mono(meth)acrylate, propoxylated trimethylolpropane mono(meth)acrylate, tris(2-hydroxyethyl) isocyanurate mono(meth)acrylate, glycerin mono(meth)acrylate, trimethylolpropane di(meth)acrylate, ethoxylated trimethylolpropane di(meth)acrylate, propoxylated trimethylolpropane di(meth)acrylate, tris(2-hydroxyethyl) isocyanurate di(meth)acrylate, and glycerin di(meth)acrylate; and mono or di(meth)acrylates obtained by modifying some of the hydroxyl groups of these alcohols with alkyl groups or ε-caprolactone;

[0031] Examples include polyfunctional (meth)acrylates of tetravalent or higher alcohols having hydroxyl groups, such as pentaerythritol mono(meth)acrylate, dipentaerythritol mono(meth)acrylate, ditrimethylolpropane mono(meth)acrylate, pentaerythritol di(meth)acrylate, dipentaerythritol di(meth)acrylate, ditrimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, dipentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and ditrimethylolpropane hexa(meth)acrylate, as well as polyfunctional (meth)acrylates having hydroxyl groups obtained by modifying some of the hydroxyl groups of these alcohols with alkyl groups or ε-caprolactone.

[0032] Furthermore, mixtures containing polyfunctional (meth)acrylate compounds having hydroxyl groups may be used, for example, a mixture of pentaerythritol tri(meth)acrylate and pentaerythritol tetra(meth)acrylate; a mixture of dipentaerythritol penta(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol tri(meth)acrylate, dipentaerythritol di(meth)acrylate and dipentaerythritol hexa(meth)acrylate; a mixture of trimethylolpropane di(meth)acrylate and trimethylolpropane tri(meth)acrylate, etc.

[0033] Among these, the polyfunctional (meth)acrylate compound (C) having a hydroxyl group is preferably at least one compound selected from the group consisting of glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, 2-hydroxy-3-methacrylpropyl(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate. If the above compound is used, it is easier to obtain a urethane (meth)acrylate resin that has high coating hardness and can form a cured coating film with excellent curl resistance.

[0034] The hydroxyl value of the polyfunctional (meth)acrylate compound (C) having hydroxyl groups is not particularly limited, but is preferably 30 mg KOH / g or more, more preferably 50 mg KOH / g or more, preferably 300 mg KOH / g or less, and more preferably 200 mg KOH / g or less. If the above hydroxyl value is above the above lower limit, the content of the polyfunctional (meth)acrylate compound that does not react with the isocyanate will be small, so curing shrinkage during curing will be small and curling will be suppressed. Also, if the above hydroxyl value is below the above upper limit, the molecular weight of the resulting urethane (meth)acrylate resin will not be too large and will tend to be easier to handle.

[0035] A commercially available polyfunctional (meth)acrylate compound (C) having a hydroxyl group can be used. Examples of commercially available polyfunctional (meth)acrylate compounds (C) having a hydroxyl group include "Aronix® MT-3545", "Aronix® M-920", and "Aronix® M-933" manufactured by Toagosei Co., Ltd., and "Viscote® 300" manufactured by Osaka Organic Chemical Industry Co., Ltd.

[0036] <Other optional reaction materials> The urethane (meth)acrylate resin of the present invention may include any other reaction materials in addition to reaction materials (A) to (C) as needed. The other reaction materials are not particularly limited, but examples include polyol compounds other than reaction materials (A) to (C).

[0037] Examples of polyol compounds include polyol monomers such as ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 3-methyl-1,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, glycerin, glycerin mono(meth)acrylate, trimethylolethane, trimethylolmethane mono(meth)acrylate, trimethylolpropane, trimethylolpropane mono(meth)acrylate, pentaerythritol mono(meth)acrylate, and pentaerythritol di(meth)acrylate; and the above polyol monomers and succinic acid, adipic acid, azelaic acid, and sebacic acid. Examples include polyester polyols obtained by co-condensation with dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, tetrahydrophthalic acid, hexahydrophthalic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, and 1,4-cyclohexanedicarboxylic acid; lactone-type polyester polyols obtained by polycondensation reactions of the above polyol monomers with various lactones such as ε-caprolactone, δ-valerolactone, and 3-methyl-δ-valerolactone; and polyether polyols obtained by ring-opening polymerization of the above polyol monomers with cyclic ether compounds such as ethylene oxide, propylene oxide, tetrahydrofuran, ethyl glycidyl ether, and propyl glycidyl ether. These polyol compounds can be used individually or in combination of two or more.

[0038] Furthermore, when other optional reaction materials are used, the effects of the present invention are fully realized. Therefore, the amount (solid content mass) of other optional reaction materials is preferably 50% by mass or less, more preferably 30% by mass or less, and particularly preferably 10% by mass or less, in the total reaction materials of the urethane (meth)acrylate resin of the present invention.

[0039] (Method for manufacturing urethane (meth)acrylate resin) The method for producing the urethane (meth)acrylate resin of the present invention is not particularly limited, and conventionally known methods can be used. Examples of urethane reactions of isocyanate compound (A), isocyanurate ethylene oxide modified (meth)acrylate compound (B), and polyfunctional (meth)acrylate compound having a hydroxyl group (C) include a method in which isocyanate compound (A), isocyanurate ethylene oxide modified (meth)acrylate compound (B), and polyfunctional (meth)acrylate compound having a hydroxyl group (C) are reacted simultaneously, or a method in which isocyanate compound (A) is reacted after isocyanurate ethylene oxide modified (meth)acrylate compound (B) and polyfunctional (meth)acrylate compound having a hydroxyl group (C).

[0040] The urethane reaction is preferably carried out under conditions such as 20°C to 120°C and 2 to 30 hours, with an organic solvent mixed in as needed. Although the urethane reaction can be carried out without a catalyst, it is preferable to carry it out in the presence of a catalyst to accelerate the reaction.

[0041] Examples of catalysts include organometallic compounds such as dibutyltin dilaurate, dibutyltin diacetate, trimethyltin hydroxide, tetra-n-butyltin, zinc bisacetylacetonate, zirconium tris(acetylacetonate)ethylacetoacetate, zirconium tetraacetylacetonate, tin octoate, zinc hexanoate, zinc octoate, zinc stearate, zirconium 2-ethylhexanoate, cobalt naphthenate, stannous chloride, stannous chloride, potassium acetate, triethylamine, triethylenediamine, benzyldiethylamine, 1,4-diazabicyclo[2,2,2]octane, 1,8-diazabicyclo[5,4,0]undecene, N,N, Examples of bismuth catalysts include amine catalysts such as N',N'-tetramethyl-1,3-butanediamine, N-methylmorpholine, and N-ethylmorpholine; bismuth nitrate, bismuth bromide, bismuth iodide, and bismuth sulfide; organic bismuth compounds such as dibutylbismuth dilaurate and dioctylbismuth dilaurate; and bismuth-based catalysts such as bismuth 2-ethylhexanoate, bismuth naphthenate, bismuth isodecanate, bismuth neodecanoate, bismuth laurylate, bismuth maleate, bismuth stearate, bismuth oleate, bismuth linoleate, bismuth acetate, bismuth lybisneodecanoate, bismuth disalicylate, and bismuth digallate. These can be used individually or in combination of two or more.

[0042] Any organic solvent that does not have a functional group that reacts with isocyanate groups can be used as the organic solvent in the urethane reaction. For example, esters such as ethyl acetate, butyl acetate, and 2-methoxy-1-methylethyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatics such as toluene and xylene can be used.

[0043] The urethane reaction may further involve the use of polymerization inhibitors. Conventionally known polymerization inhibitors can be used, such as quinones including p-benzoquinone, naphthoquinone, tolquinone, and 2,5-diphenyl-p-benzoquinone; and phenols including hydroquinone, 2,5-di-t-butylhydroquinone, methylhydroquinone, mono-t-butylhydroquinone, 4-methoxyphenol, 2,6-di-t-butylcéchol, and pt-butylcatechol. These can be used individually or in combination of two or more.

[0044] When reacting each reaction material, the molar ratio (NCO / OH ratio) of total isocyanate groups to total hydroxyl groups in each reaction material (A) to (C) is not particularly limited, but is preferably 0.5 or higher, and preferably 2.0 or lower. When the above NCO / OH ratio is within the above range, the number-average molecular weight of the urethane (meth)acrylate composition tends to be within the desired range, making it easier to obtain a urethane (meth)acrylate resin with good compatibility with various solvents and active energy ray polymerizable monomers.

[0045] The weight-average molecular weight (Mw) of the urethane (meth)acrylate resin is not particularly limited, but is preferably 1,000 or more, and preferably 80,000 or less. When the weight-average molecular weight is above the lower limit, a cured coating film with high hardness is easily obtained, and when it is below the upper limit, it tends to have a moderate viscosity and be easy to handle.

[0046] The (meth)acrylic group concentration of the urethane (meth)acrylate resin is preferably 4.0 to 8.0 mmol / g, more preferably 4.2 to 7.5 mmol / g, and particularly preferably 4.5 to 7.0 mmol / g. If the (meth)acrylic group concentration is within the range of 4.0 to 8.0 mmol / g, a urethane (meth)acrylate resin capable of forming a cured coating film with high hardness can be obtained. The (meth)acrylic group concentration refers to the amount of (meth)acrylic groups (mmol) per gram of urethane (meth)acrylate resin. The (meth)acryloyl group concentration is a value calculated theoretically from the reaction raw materials.

[0047] The urethane bond concentration of the urethane (meth)acrylate resin is preferably 1.0 to 3.0 mmol / g, more preferably 1.02 to 2.80 mmol / g, and particularly preferably 1.05 to 2.50 mmol / g. If the urethane bond concentration is within the range of 1.00 to 3.00 mmol / g, a urethane (meth)acrylate resin capable of forming a cured coating film with excellent curl resistance can be obtained. The urethane bond concentration refers to the amount of urethane bonds (mmol) per gram of urethane (meth)acrylate resin. Furthermore, the urethane bond concentration is a value calculated theoretically from the reaction raw materials.

[0048] The sum of the (meth)acrylic group concentration and the urethane bond concentration of the urethane (meth)acrylate resin ((meth)acrylic group concentration (mmol / g) + urethane bond concentration (mmol / g)) is preferably 5.0 to 11.0 mmol / g, more preferably 5.22 to 10.3 mmol / g, and particularly preferably 5.55 to 9.50 mmol / g. When the sum of the above concentrations is within the range of 5.0 to 11.0 mmol / g, there is a tendency to obtain a urethane (meth)acrylate resin that can form a cured coating film with high coating hardness and excellent curl resistance.

[0049] (Active energy ray curable composition) The active energy ray curable composition of the present invention (hereinafter also simply referred to as "the composition") contains the urethane (meth)acrylate resin of the present invention and a photopolymerization initiator.

[0050] <Photopolymerization initiator> The type of photopolymerization initiator used in the composition of the present invention is not particularly limited, and conventionally known photopolymerization initiators can be used.

[0051] Examples of photopolymerization initiators include various benzophenones such as benzophenone, 3,3′-dimethyl-4-methoxybenzophenone, 4,4′-bisdimethylaminobenzophenone, 4,4′-bisdiethylaminobenzophenone, 4,4′-dichlorobenzophenone, Michlar's ketone, and 3,3′,4,4′-tetra(t-butylperoxycarbonyl)benzophenone;

[0052] Xanthones, thioxanthones, 2-methylthioxanthone, 2-chlorothioxanthone, 2,4-diethylthioxanthone, and other xanthones and thioxanthones; various acyloin ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether;

[0053] α-diketones such as benzyl and diacetyl; sulfides such as tetramethylthiuram disulfide and p-tolyl disulfide; various benzoic acids such as 4-dimethylaminobenzoic acid and ethyl 4-dimethylaminobenzoate;

[0054] 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one,3,3′-carbonyl-bis(7-diethylamino)coumarin,1-hydroxycyclohexylphenyl ketone,2,2′-dimethoxy-1,2-diphenylethane-1-one,2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one,2-H Droxy-2-methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-(4-dodecylphenyl)-2-hydroxy-2 -Methylpropan-1-one, 4-benzoyl-4′-methyldimethyl sulfide, 2,2′-diethoxyacetophenone, benzyldimethyl ketal, benzyl-β-methoxyethyl acetal, o-benzoylmethyl benzoate, bis(4-dimethylaminophenyl) ketone, p-dimethylaminoacetophenone, α,α-dichloro-4-phenoxyacetophenone, pentyl-4-dimethylaminobenzoate, 2-(o-chlorophenyl)-4,5-di Examples include phenylimidazolyl dimer, 2,4-bis-trichloromethyl-6-[di-(ethoxycarbonylmethyl)amino]phenyl-S-triazine, 2,4-bis-trichloromethyl-6-(4-ethoxy)phenyl-S-triazine, 2,4-bis-trichloromethyl-6-(3-bromo-4-ethoxy)phenyl-S-triazine anthraquinone, 2-t-butylanthraquinone, 2-amylanthraquinone, and β-chloranthraquinone. These photopolymerization initiators can be used alone or in combination of two or more.

[0055] Furthermore, among the above photopolymerization initiators, it is preferable to use one or more mixed systems selected from the group consisting of 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, thioxanthone and thioxanthone derivatives, 2,2′-dimethoxy-1,2-diphenylethane-1-one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, and 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one, as these exhibit activity to a wider range of wavelengths of light and can improve the curability of the cured coating film of the above active energy ray curable composition.

[0056] Commercially available photopolymerization initiators include, for example, IGM's "Omnirad-1173", "Omnirad-184", "Omnirad-127", "Omnirad-2959", "Omnirad-369", "Omnirad-379", "Omnirad-907", "Omnirad-4265", "Omnirad-1000", "Omnirad-651", "Omnirad-TPO", "Omnirad-819", "Omnirad-2022", "Omnirad-2100", "Omnirad-754", "Omnirad-784", and "Omnirad Examples include "-500", "Omnirad-81", "KayaCure-DETX", "KayaCure-MBP", "KayaCure-DMBI", "KayaCure-EPA", and "KayaCure-OA" from Nippon Kayaku Co., Ltd., "VyCure-10" and "VyCure-55" from Stoufa Chemical, "Trigonal P1" from Akzo, "Sandoz-1000" from Sandoz, "Deep" and "Quantacure-PDO" from Apjohn, "Quantacure-ITX" and "Quantacure-EPD" from Wardbrenkinsop, and "Runtecure(registered trademark)-1104" from Runtec.

[0057] The amount of photopolymerization initiator added is preferably an amount that can fully exhibit its function as a photopolymerization initiator, and is within a range that does not cause crystal precipitation or deterioration of the coating film properties. Specifically, it is preferably in the range of 0.05 to 20 parts by mass, and more preferably in the range of 0.1 to 10 parts by mass, per 100 parts by mass of urethane (meth)acrylate resin.

[0058] Furthermore, since the active energy ray curable composition can improve the curability of the cured coating film, it may also contain a photosensitizer.

[0059] Examples of photosensitizers include amine compounds such as aliphatic amines and aromatic amines, urea compounds such as o-tolylthiourea, and sulfur compounds such as sodium diethyldithiophosphate and s-benzylisothironium-p-toluenesulfonate.

[0060] (Other optional additives) The active energy ray curable composition of the present invention may further contain, in addition to the urethane (meth)acrylate resin, other photocurable compounds, organic solvents, ultraviolet absorbers, antioxidants, silicone-based additives, fluorine-based additives, silane coupling agents, phosphate ester compounds, organic beads, inorganic fine particles, inorganic fillers, rheology control agents, defoaming agents, antifogging agents, colorants, and the like as additives.

[0061] Other photocurable compounds include, for example, various (meth)acrylate monomers, other urethane (meth)acrylate resins other than the urethane (meth)acrylate resins mentioned above, epoxy (meth)acrylate resins, dendrimer-type (meth)acrylate resins, and (meth)acryloyl group-containing acrylic resins.

[0062] (Meth)acrylate monomers include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, glycidyl (meth)acrylate, acryloylmorpholine, N-vinylpyrrolidone, tetrahydrofurfluryl acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, isode Syl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, benzyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phosphate (meth)acrylate, ethylene oxide-modified phosphate (meth)acrylate, phenoxy (meth)acrylate, ethylene oxide-modified phenoxy (meth)acrylate, propylene oxide-modified phenoxy (meth)acrylate, nonylphenol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, propylene oxide-modified nonylphenol (meth)acrylate, methoxydiethylene glycol (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypropylene glycol (meth)acrylate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, 2-(meth)acryloyloxy Ethyl hydrogen phthalate, 2-(meth)acryloyloxypropyl hydrogen phthalate, 2-(meth)acryloyloxypropyl hexahydrohydrogen phthalate, 2-(meth)acryloyloxypropyl tetrahydrohydrogen phthalate, dimethylaminoethyl (meth)acrylate, trifluoroethyl (meth)acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropropyl (meth)acrylate, octafluoropropyl (meth)acrylate,Mono(meth)acrylates such as adamantyl mono(meth)acrylate;

[0063] Di(meth)acrylates such as butanediol di(meth)acrylate, hexanediol di(meth)acrylate, ethoxylated hexanediol di(meth)acrylate, propoxylated hexanediol di(meth)acrylate, diethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, ethoxylated neopentyl glycol di(meth)acrylate, hydroxypivalate neopentyl glycol di(meth)acrylate, glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol di(meth)acrylate, etc.

[0064] Trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, glycerin tri(meth)acrylate, ditrimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol tri(meth)acrylate, and other tri(meth)acrylates;

[0065] Examples include (meth)acrylates with four or more functions, such as pentaerythritol tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, ditrimethylolpropane penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and ditrimethylolpropane hexa(meth)acrylate; and (meth)acrylates in which some or all of the above-mentioned polyfunctional (meth)acrylates are modified with polyoxyalkylene chains or polyester chains.

[0066] Other urethane (meth)acrylate resins include, for example, urethane (meth)acrylate resins using isocyanate compounds other than the isocyanate compound (A) mentioned above.

[0067] Examples of epoxy (meth)acrylate resins include those obtained by reacting various epoxy resins, such as bisphenol-type epoxy resins and novolac-type epoxy resins, with (meth)acrylic acid or its derivatives to produce (meth)acrylates.

[0068] Dendrimer-type (meth)acrylate resins are resins that have a regularly branched structure with a (meth)acryloyl group at the end of each branched chain. They are also called hyperbranched polymers or star polymers. Examples of such compounds include those represented by the structural formulas (2-1) to (2-8) below, but are not limited to these. Any resin that has a regularly branched structure with a (meth)acryloyl group at the end of each branched chain can be used.

[0069] [ka] (R in the formula 3 R is a hydrogen atom or a methyl group, 4 (This refers to a hydrocarbon group with 1 to 4 carbon atoms.)

[0070] [ka] (R in the formula 3 R is a hydrogen atom or a methyl group, 4 (This refers to a hydrocarbon group with 1 to 4 carbon atoms.)

[0071] Examples of such dendrimer-type (meth)acrylate resins include "Biscote #1000" [weight-average molecular weight (Mw) 1,500-2,000, average number of (meth)acryloyl groups per molecule 14], "Biscote 1020" [weight-average molecular weight (Mw) 1,000-3,000], and "SIRIUS501" [weight-average molecular weight (Mw) 15,000-23,000] from Osaka Organic Chemical Co., Ltd., and "SP-1106" [weight-average molecular weight (Mw) 1,630, average number of (meth)acryloyl groups per molecule 1] from MIWON Corporation. 8] Commercially available products such as SARTOMER's "CN2301", "CN2302" [average number of (meth)acryloyl groups per molecule: 16], "CN2303" [average number of (meth)acryloyl groups per molecule: 6], "CN2304" [average number of (meth)acryloyl groups per molecule: 18], Nippon Steel & Sumitomo Metal Chemical Co., Ltd.'s "Esdrimer HU-22", Shin Nakamura Chemical Co., Ltd.'s "A-HBR-5", Daiichi Kogyo Seiyaku Co., Ltd.'s "New Frontier R-1150", and Nissan Chemical Corporation's "Hypertech UR-101" may also be used.

[0072] The weight-average molecular weight (Mw) of the dendrimer-type (meth)acrylate resin is preferably in the range of 1,000 to 30,000. Furthermore, the average number of (meth)acryloyl groups per molecule is preferably in the range of 5 to 30.

[0073] Examples of acrylic resins containing (meth)acryloyl groups include those obtained by polymerizing an acrylic resin intermediate obtained by polymerizing an acrylic resin intermediate having a reactive functional group such as a hydroxyl group, carboxyl group, isocyanate group, or glycidyl group, and then further reacting it with an acrylic resin intermediate having a reactive functional group that can react with these functional groups, thereby introducing a (meth)acryloyl group.

[0074] Examples of (meth)acrylate monomers (α) having reactive functional groups include hydroxyl group-containing (meth)acrylate monomers such as hydroxyethyl (meth)acrylate and hydroxypropyl (meth)acrylate; carboxyl group-containing (meth)acrylate monomers such as (meth)acrylic acid; isocyanate group-containing (meth)acrylate monomers such as 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate, and 1,1-bis(acryloyloxymethyl)ethyl isocyanate; and glycidyl group-containing (meth)acrylate monomers such as glycidyl (meth)acrylate and 4-hydroxybutyl acrylate glycidyl ether. These (meth)acrylate monomers (α) can be used alone or in combination of two or more.

[0075] The acrylic resin intermediate may be copolymerized with other polymerizable unsaturated group-containing compounds as needed, in addition to the (meth)acrylate monomer (α) mentioned above. Examples of other polymerizable unsaturated group-containing compounds include alkyl (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; cyclo-ring-containing (meth)acrylates such as cyclohexyl (meth)acrylate, isobolonyl (meth)acrylate, and dicyclopentanyl (meth)acrylate; aromatic-ring-containing (meth)acrylates such as phenyl (meth)acrylate, benzyl (meth)acrylate, and phenoxyethyl acrylate; silyl-ring-containing (meth)acrylates such as 3-methacryloxypropyltrimethoxysilane; and styrene derivatives such as styrene, α-methylstyrene, and chlorostyrene. These polymerizable unsaturated group-containing compounds can be used individually or in combination of two or more. Furthermore, among these, alkyl (meth)acrylates are preferred.

[0076] When the acrylic resin intermediate is obtained by copolymerizing the above-mentioned (meth)acrylate monomer (α) with the above-mentioned other polymerizable unsaturated group-containing compound, the reaction ratio of the two is such that the resulting acrylic resin contains (meth)acryloyl groups and exhibits excellent curability. Therefore, the ratio of the above-mentioned (meth)acrylate monomer (α) to the total of the two is preferably in the range of 20 to 70% by mass, and more preferably in the range of 30 to 60% by mass.

[0077] Acrylic resin intermediates can be manufactured in the same manner as general acrylic resins. For example, they can be manufactured by polymerizing various monomers in the presence of a polymerization initiator at a temperature range of 60 to 150°C. Examples of polymerization methods include bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. Examples of polymerization modes include random copolymers, block copolymers, and graft copolymers. When using the solution polymerization method, it is preferable to use ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone, or glycol ether solvents such as propylene glycol monomethyl ether, propylene glycol dimethyl ether, propylene glycol monopropyl ether, and propylene glycol monobutyl ether.

[0078] The (meth)acrylate monomer (β) is not particularly limited as long as it can react with the reactive functional group of the (meth)acrylate monomer (α), but from the viewpoint of reactivity, the following combinations are preferred. That is, when the hydroxyl group-containing (meth)acrylate is used as the (meth)acrylate monomer (α), it is preferable to use an isocyanate group-containing (meth)acrylate as the (meth)acrylate monomer (β). When the carboxyl group-containing (meth)acrylate is used as the (meth)acrylate monomer (α), it is preferable to use a glycidyl group-containing (meth)acrylate as the (meth)acrylate monomer (β). When the isocyanate group-containing (meth)acrylate is used as the (meth)acrylate monomer (α), it is preferable to use a hydroxyl group-containing (meth)acrylate as the (meth)acrylate monomer (β). When the above-mentioned glycidyl group-containing (meth)acrylate is used as the (meth)acrylate monomer (α), it is preferable to use the above-mentioned carboxyl group-containing (meth)acrylate as the (meth)acrylate monomer (β).

[0079] The reaction between the acrylic resin intermediate and the above-mentioned (meth)acrylate monomer (β) can be carried out, for example, in the case of an esterification reaction, at a temperature range of 60 to 150°C using an appropriate esterification catalyst such as triphenylphosphine. In the case of a urethane reaction, a method can be carried out at a temperature range of 50 to 120°C while adding the above-mentioned (meth)acrylate monomer (α) dropwise to the acrylic resin intermediate.

[0080] The weight-average molecular weight (Mw) of the (meth)acryloyl group-containing acrylic resin is preferably in the range of 5,000 to 80,000. Furthermore, the equivalent weight of the (meth)acryloyl group is preferably in the range of 100 to 500 g / equivalent.

[0081] These other photocurable compounds may be used individually or in combination of two or more. When using these other photocurable compounds, it is preferable that the urethane (meth)acrylate resin of the present invention be used in a proportion of 5 parts by mass or more, more preferably 20 parts by mass or more, and particularly preferably 80 parts by mass or more, out of a total of 100 parts by mass of the urethane (meth)acrylate resin of the present invention and the other photocurable compounds.

[0082] Examples of organic solvents include ketone solvents such as methyl ethyl ketone, acetone, and isobutyl ketone; cyclic ether solvents such as tetrahydrofuran and dioxolane; ester solvents such as methyl acetate, ethyl acetate, and butyl acetate; aromatic solvents such as toluene and xylene; alicyclic solvents such as cyclohexane and methylcyclohexane; alcohol solvents such as carbitol, cellosolve, methanol, isopropanol, butanol, and propylene glycol monomethyl ether; and glycol ether solvents such as alkylene glycol monoalkyl ether, dialkylene glycol monoalkyl ether, and dialkylene glycol monoalkyl ether acetate. These organic solvents can be used individually or in combination of two or more. These organic solvents are mainly used to adjust the viscosity of the composition, and it is generally preferable to adjust the non-volatile content to be in the range of 10 to 80% by mass.

[0083] Examples of UV absorbers include triazine derivatives such as 2-[4-{(2-hydroxy-3-dodecyloxypropyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine and 2-[4-{(2-hydroxy-3-tridecyloxypropyl)oxy}-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2'-xanthen carboxy-5'-methylphenyl)benzotriazole, 2-(2'-o-nitrobenzyloxy-5'-methylphenyl)benzotriazole, 2-xanthen carboxy-4-dodecyloxybenzophenone, and 2-o-nitrobenzyloxy-4-dodecyloxybenzophenone. These UV absorbers can be used individually or in combination of two or more.

[0084] Examples of antioxidants include hindered phenol antioxidants, hindered amine antioxidants, organosulfur antioxidants, and phosphate ester antioxidants. These antioxidants can be used individually or in combination of two or more.

[0085] Examples of silicon-based additives include polyorganosiloxanes having alkyl or phenyl groups, such as dimethylpolysiloxane, methylphenylpolysiloxane, cyclic dimethylpolysiloxane, methylhydrogenpolysiloxane, polyether-modified dimethylpolysiloxane copolymer, polyester-modified dimethylpolysiloxane copolymer, fluorine-modified dimethylpolysiloxane copolymer, and amino-modified dimethylpolysiloxane copolymer; polydimethylsiloxane having polyether-modified acrylic groups; and polydimethylsiloxane having polyester-modified acrylic groups. These silicon-based additives can be used individually or in combination of two or more types.

[0086] Examples of fluorine-based additives include the "Megaface" series manufactured by DIC Corporation. These fluorine-based additives can be used individually or in combination of two or more types.

[0087] Examples of silane coupling agents include vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3 -Vinyl-based silane coupling agents such as aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-3-aminopropyltrimethoxysilane, hydrochloride salt of N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane, special aminosilanes, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatetopropyltriethoxysilane, allyltrichlorosilane, allyltriethoxysilane, allyltrimethoxysilane, diethoxymethylvinylsilane, trichlorovinylsilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane;

[0088] Epoxy-based silane coupling agents such as diethoxy(glycidyloxypropyl)methylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyltriethoxysilane;

[0089] Styrene-based silane coupling agents such as p-styryltrimethoxysilane;

[0090] (Meth)acryloxy-based silane coupling agents such as 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 3-methacryloxypropyltriethoxysilane;

[0091] Amino-based silane coupling agents such as N-2(aminoethyl)3-aminopropylmethyldimethoxysilane, N-2(aminoethyl)3-aminopropyltrimethoxysilane, N-2(aminoethyl)3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutylidene)propylamine, and N-phenyl-3-aminopropyltrimethoxysilane;

[0092] Ureidopropyltriethoxysilane and other ureidopropyl silane coupling agents;

[0093] Chloropropyl silane coupling agents such as 3-chloropropyltrimethoxysilane;

[0094] Mercaptopropyl silane coupling agents such as 3-mercaptopropylmethyldimethoxysilane and 3-mercaptopropyltrimethoquinsilane;

[0095] Sulfide-based silane coupling agents such as bis(triethoxysilylpropyl)tetrasulfide;

[0096] Examples include isocyanate-based silane coupling agents such as 3-isocyanate-propyltriethoxysilane. These silane coupling agents can be used individually or in combination of two or more.

[0097] Examples of phosphate ester compounds include those having a (meth)acryloyl group in their molecular structure. Commercially available examples include "Kayama PM-2" and "Kayama PM-21" from Nippon Kayaku Co., Ltd., "Light Ester P-1M," "Light Ester P-2M," and "Light Acrylate P-1A(N)" from Kyoeisha Chemical Co., Ltd., "SIPOMER PAM 100," "SIPOMER PAM 200," "SIPOMER PAM 300," and "SIPOMER PAM 4000" from SOLVAY, "Viscote #3PA" and "Viscote #3PMA" from Osaka Organic Chemical Industry Co., Ltd., and "New Frontier S-23A" from Daiichi Kogyo Seiyaku Co., Ltd.; and "SIPOMER PAM 5000" from SOLVAY, which is a phosphate ester compound having an allyl ether group in its molecular structure.

[0098] Examples of organic beads include polymethyl methacrylate beads, polycarbonate beads, polystyrene beads, polyacrylic styrene beads, silicone beads, glass beads, acrylic beads, benzoguanamine resin beads, melamine resin beads, polyolefin resin beads, polyester resin beads, polyamide resin beads, polyimide resin beads, polyfluoroethylene resin beads, and polyethylene resin beads. These organic beads can be used individually or in combination of two or more types. The average particle size of these organic beads is preferably in the range of 1 to 10 μm.

[0099] Examples of inorganic nanoparticles include silica, alumina, zirconia, titania, barium titanate, and antimony trioxide. These inorganic nanoparticles can be used individually or in combination of two or more types. The average particle size of these inorganic nanoparticles is preferably in the range of 95 to 250 nm, and more preferably in the range of 100 to 180 nm.

[0100] When inorganic fine particles are included, a dispersion aid can be used. Examples of the above dispersion aid include isopropyl acid phosphate, triisodecyl phosphite, ethylene oxide-modified phosphate dimethacrylate and other phosphate ester compounds. These dispersion aids can be used alone or in combination of two or more. Examples of commercially available dispersion aids include "Kayama PM-21" and "Kayama PM-2" manufactured by Nippon Kayaku Co., Ltd., and "Light Ester P-2M" manufactured by Kyoeisha Chemical Co., Ltd.

[0101] (cured coating) The cured coating film of the present invention is a cured reaction product obtained by curing the active energy ray curable composition of the present invention.

[0102] Methods for curing active energy ray-curable compositions include, for example, heating and irradiation with active energy rays such as ultraviolet light.

[0103] The material can be cured by heating it in a temperature range of 60-200°C for 0.5-60 minutes.

[0104] Furthermore, as a method of irradiating with active energy rays, for example, in the case of ultraviolet light, curing can be achieved by using ultraviolet lamps such as low-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, gallium lamps, metal halide lamps, sunlight, and LEDs as ultraviolet light sources.

[0105] As the active energy rays, in addition to the above-mentioned ultraviolet rays, for example, ionizing radiations such as electron beams, α-rays, β-rays, γ-rays, etc. can also be used.

[0106] The irradiation amount of the active energy rays is preferably in the range of 0.05 to 5 J / cm 2 more preferably in the range of 0.1 to 3 J / cm 2 even more preferably in the range of 0.1 to 1 J / cm 2 and particularly preferably in the range of 0.1 to 1 J / cm. The above-mentioned ultraviolet ray irradiation amount is based on the value measured in the wavelength range of 300 to 390 nm using a UV checker UVR-N1 (manufactured by Nippon Denchi Co., Ltd.).

[0107] (Hard coat film) The hard coat film of the present invention contains the cured coating film of the present invention and a substrate. More specifically, the hard coat film of the present invention has a layer made of the cured coating film of the present invention on the substrate.

[0108] As a method for manufacturing the hard coat film of the present invention, for example, a method of applying an active energy ray curable composition to at least one surface of a substrate and then irradiating it with active energy rays can be mentioned.

[0109] Examples of the substrate include a metal substrate, a plastic substrate, a glass substrate, a paper substrate, a wood substrate, a fibrous substrate, etc. Among these substrates, a plastic substrate is preferable because of its excellent adhesion to the active energy ray curable composition.

[0110] Examples of the material of the plastic substrate include polyester, acrylic resin (such as polymethyl methacrylate), polycarbonate, acrylonitrile-butadiene-styrene copolymer (ABS resin), a composite resin of ABS resin and polycarbonate, polystyrene, polyurethane, epoxy resin, polyvinyl chloride, polyamide, polyolefin (such as polyethylene, polypropylene, polycycloolefin (COP), etc.), triacetyl cellulose (TAC), polyimide, etc.

[0111] Examples of plastic substrates include plastic molded products such as mobile phones, home appliances, automotive interior and exterior materials, and office automation equipment. Film substrates made from plastic can also be used.

[0112] Methods for applying the active energy ray-curable composition include, for example, application methods using a gravure coater, roll coater, comma coater, knife coater, air knife coater, curtain coater, kiss coater, shower coater, flow coater, spin coater, dipping, screen printing, spray, brush application, applicator, bar coater, etc.

[0113] The film thickness of the coating formed using the active energy ray curable composition can be adjusted as appropriate depending on the application, but is generally preferably in the range of 0.01 to 50 μm.

[0114] The hard coat film of the present invention may have a functional film layer such as an anti-reflective film, a diffusion film, or a polarizing film, in addition to the substrate and the layer made of the cured product.

[0115] The hard coat film of the present invention has a cured coating with excellent hardness, scratch resistance, flexibility, and curl resistance, and can therefore be used as a protective coating layer for the surface of a substrate. For example, it can be suitably used for front panels of liquid crystal displays and organic EL displays.

[0116] Furthermore, examples of articles having the hard coat film of the present invention include plastic molded products such as mobile phones, home appliance casings, automobile bumpers, and office automation equipment. [Examples]

[0117] 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. Unless otherwise specified, "parts," "%," etc., in the examples refer to mass-based measurements.

[0118] [Raw materials] The raw materials used in the examples and comparative examples are as follows:

[0119] <Isocyanate compound (A)> <a1>1,6-Hexamethylene diisocyanate biuret (product name: Duranate 24A-100, manufactured by Asahi Kasei Corporation) <a2>Isocyanurate group-containing polyisocyanate (product name: DN902S, manufactured by DIC Corporation) <a3>1,3-Bis(isocyanatomethyl)cyclohexane (Trade name: Takenate® 600, manufactured by Mitsui Chemicals, Inc.) <a4>1,6-Hexamethylene diisocyanate (Product name: Duranate 50M-HDI, manufactured by Asahi Kasei Corporation)

[0120] <Isocyanurate ethylene oxide (EO) modified (meth)acrylate compound (B)> <b1>Isocyanuric acid EO-modified di and triacrylates (di-isomer:tri-isomer = 3:7, trade name: Aronics® M-313, hydroxyl value 44 mg KOH / g, manufactured by Toagosei Co., Ltd.) <b2>Isocyanuric acid EO-modified diacrylate (Trade name: Aronics® M-215, hydroxyl value 127 mg KOH / g, manufactured by Toagosei Co., Ltd.)

[0121] <Polyfunctional (meth)acrylate compound (C) containing a hydroxyl group> <c1>High hydroxyl value dipentaerythritol acrylate (product name: Aronics® MT-3545, hydroxyl value 123 mg KOH / g, manufactured by Toagosei Co., Ltd.) <c2>High hydroxyl value pentaerythritol acrylate (product name: Aronics® M-933, hydroxyl value 271 mg KOH / g, manufactured by Toagosei Co., Ltd.) <c3>Glycerin diacrylate (Product name: Aronics® M-920, hydroxyl value 235 mg KOH / g, manufactured by Toagosei Co., Ltd.) The above hydroxyl value was measured in accordance with JIS K0070-1992, which means it is the number of milligrams of potassium hydroxide required to neutralize the acetic acid bonded to the hydroxyl group when acetylating 1 g of polyfunctional (meth)acrylate.

[0122] Table 1 below shows a list of the above raw materials. [Table 1]

[0123] <Photocurable compound> <d1>High hydroxyl value dipentaerythritol acrylate (product name: Aronics® MT-3545, hydroxyl value 123 mg KOH / g, manufactured by Toagosei Co., Ltd.)

[0124] <Additives> <e1>A fluorine-based compound with polymerizable groups (product name: KY-1203, manufactured by Shin-Etsu Chemical Co., Ltd.) <e2>Silicone-modified acrylate (product name: TEGO® Rad 2200, manufactured by Evonik)

[0125] <Photopolymerization initiator> <f1>2-Methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (Trade name: OMNIRAD 907, manufactured by IGM Resins)

[0126] Table 2 below shows a list of the above raw materials. [Table 2]

[0127] The urethane (meth)acrylate resin was prepared as follows: (Manufacturing example 1: Manufacturing of urethane (meth)acrylate resin (1)) In a flask equipped with a stirring rod, temperature sensor, and water-cooled condenser, 30.00 parts by mass of methyl ethyl ketone, 41.08 parts by mass of Aronics M-313 (isocyanuric acid EO-modified triacrylate, hydroxyl value 44 mg KOH / g, manufactured by Toagosei Co., Ltd.), 18.67 parts by mass of Aronics MT-3545 (high hydroxyl value dipentaerythritol acrylate, hydroxyl value 123 mg KOH / g, manufactured by Toagosei Co., Ltd.), 0.01 parts by mass of methoquinone, 0.1 parts by mass of dibutylhydroxytoluene, and 0.03 parts by mass of Zn-octoate were charged and mixed with a stirring blade, and the temperature was raised to 60°C while blowing in dry air. 6.54 parts by mass of Duranate 24A-100 (biuret form of 1,6-hexamethylene diisocyanate, manufactured by Asahi Kasei Corporation) and 3.55 parts by mass of Takenate 600 (1,3-bis(isocyanatomethyl)cyclohexane, manufactured by Mitsui Chemicals, Inc.) were added dropwise, taking care to avoid exothermic reactions, to carry out the urethane formation reaction. After the dropwise addition was complete, the temperature was raised to 80°C and the reaction was continued. After confirming that the isocyanate weight% had fallen to 0.20% or less, the mixture was cooled to obtain a urethane acrylate with a resin solids content of 70%. The (meth)acrylic group concentration of the urethane (meth)acrylate resin (1), calculated from the raw material charging ratio, was 6.20 mmol / g, the urethane bond concentration was 1.09 mmol / g, and the combined concentration of (meth)acrylic group concentration and urethane bond concentration was 7.29 mmol / g.

[0128] (Manufacturing Examples 2-11: Manufacturing of urethane (meth)acrylate resin (2)-(11)) Urethane (meth)acrylate resins (2) to (11) were obtained using the same method as in Example 1 with the compositions and formulations shown in Table 3.

[0129] [Table 3]

[0130] (Manufacturing examples 12-21: Manufacturing of urethane (meth)acrylate resin (R1)-(R10)) Urethane (meth)acrylate resins (R1) to (R10) were obtained using the same method as in Production Example 1 with the compositions and formulations shown in Table 4.

[0131] [Table 4]

[0132] Note that all values ​​for parts by mass in Tables 3 and 4 represent solid content.

[0133] The hard coat film was prepared as follows: (Example 1: Preparation of hard coat film (1)) An active energy ray-curable composition was obtained by blending 100 parts by mass of the urethane (meth)acrylate resin (1) obtained in Production Example 1, 2.0 parts by mass of OMNIRAD 907 (2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, manufactured by IGM Resins), and an arbitrary soluble solvent. The obtained active energy ray-curable composition was then coated onto a 50 μm thick polyethylene terephthalate film (hereinafter abbreviated as "PET film") using a bar coater and dried at 90°C for 1 minute. Then, under a nitrogen atmosphere, ultraviolet light at 100 mJ / cm² was applied using an 80 W high-pressure mercury lamp. 2 Irradiation was performed to obtain a hard coat film (1) having a cured coating film with a thickness of 7 μm on a PET film with a thickness of 50 μm.

[0134] (Examples 2 and 3: Preparation of hard coat films (2) and (3)) Using the urethane (meth)acrylate resins (2) and (3) obtained in Production Examples 2 and 3, hard coat films (2) and (3) were obtained in the same manner as the production of hard coat film (1) in Example 1.

[0135] (Example 4: Preparation of hard coat film (4)) An active energy ray-curable composition was obtained by blending 100 parts by mass of the urethane (meth)acrylate resin (3) obtained in Production Example 3, 0.1 parts by mass of KY-1203 (a fluorine-based compound having polymerizable groups, manufactured by Shin-Etsu Chemical Co., Ltd.), 2.0 parts by mass of OMNIRAD 907 (2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, manufactured by IGM Resins), and any soluble solvent. The obtained active energy ray-curable composition was then coated onto a 50 μm thick polyethylene terephthalate film (hereinafter abbreviated as "PET film") using a bar coater and dried at 90°C for 1 minute. Then, under a nitrogen atmosphere, ultraviolet light at 100 mJ / cm² was applied using an 80 W high-pressure mercury lamp. 2 Irradiation was performed to obtain a hard coat film (4) having a cured coating film with a thickness of 7 μm on a PET film with a thickness of 50 μm.

[0136] (Example 5: Preparation of hard coat film (5)) A hard coat film (5) was obtained in the same manner as the hard coat film (4) of Example 4, except that TEGO Rad 2200 (silicon-modified acrylate, manufactured by Evonik) was used instead of KY-1203 (a polymerizable fluorine compound, manufactured by Shin-Etsu Chemical Co., Ltd.).

[0137] (Examples 6-13: Preparation of hard coat films (6)-(13)) Using the urethane (meth)acrylate resins (4) to (11) obtained in manufacturing examples 4 to 11, hard coat films (6) to (13) were obtained in the same manner as the production of hard coat film (1) in Example 1.

[0138] (Example 14: Preparation of hard coat film (14)) An active energy ray-curable composition was obtained by blending 80 parts by mass of the urethane (meth)acrylate resin (3) obtained in Production Example 3, 20 parts by mass of Aronics MT-3545 (high hydroxyl value dipentaerythritol acrylate, hydroxyl value 123 mg KOH / g, manufactured by Toagosei Co., Ltd.), 2.0 parts by mass of OMNIRAD 907 (2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, manufactured by IGM Resins), and an arbitrary soluble solvent. The obtained active energy ray-curable composition was then coated onto a 50 μm thick polyethylene terephthalate film (hereinafter abbreviated as "PET film") using a bar coater and dried at 90°C for 1 minute. Then, under a nitrogen atmosphere, ultraviolet light at 100 mJ / cm² was applied using an 80 W high-pressure mercury lamp. 2 Irradiation was performed to obtain a hard coat film (14) having a cured coating film with a thickness of 7 μm on a PET film with a thickness of 50 μm.

[0139] (Example 15: Preparation of hard coat film (15)) A hard coat film (15) was obtained in the same manner as the hard coat film (14) of Example 14, except that the urethane (meth)acrylate resin (1) obtained in Production Example 1 was used instead of the urethane (meth)acrylate resin (3) obtained in Production Example 3.

[0140] (Comparative Examples 1-10: Preparation of hard coat films (R1)-(R10)) Using the active energy ray curable compositions (R1) to (R10) obtained in Production Examples 12 to 21, hard coat films (R1) to (R10) were obtained in the same manner as the production of hard coat film (1) in Example 1.

[0141] The hard coat films obtained in the above examples and comparative examples were used for the following evaluations. [Method for evaluating coating hardness] In the hard coat films obtained in the examples and comparative examples, the hardness of the cured coating surface of the active energy ray curable composition was measured under a 500g load condition in accordance with JIS K5600-5-4 [Scratch hardness (pencil method)]. Six measurements were taken for each hardness, and the hardness for which no scratches occurred in four or more measurements was defined as the hardness of the cured coating. The hardness of pencils, from hardest to hardest, is 2H, H, F, HB, and B.

[0142] [Method for evaluating curl resistance] Test specimens were obtained by cutting out 10 cm square coatings from the hard coat films obtained in the examples and comparative examples. The lift from the horizontal at the four corners of each test specimen was measured, and the average value (mm) was used for evaluation. A smaller value indicates less curl and superior curl resistance.

[0143] Tables 5 and 6 show the evaluation results.

[0144] [Table 5]

[0145] [Table 6]

[0146] Examples 1 to 15 shown in Table 5 are examples of hard coat films using the urethane (meth)acrylate resin of the present invention. The formed cured coating film exhibited excellent coating hardness, and it was confirmed that the hard coat film had excellent curl resistance.

[0147] On the other hand, Comparative Examples 1 to 4 are examples in which a polyfunctional (meth)acrylate compound (C) having a hydroxyl group was not used as a reaction raw material for the urethane (meth)acrylate resin, but it was confirmed that the formed cured coating film had insufficient coating hardness. Furthermore, Comparative Examples 5 to 10 are examples in which an isocyanurate ethylene oxide modified (meth)acrylate compound (B) was not used as a reaction raw material for the urethane (meth)acrylate resin, but although some of the formed cured coating films had excellent coating hardness, it was confirmed that the hard coat films had significantly insufficient curl resistance.

Claims

1. A urethane (meth)acrylate resin, which is a reaction product of an isocyanate compound (A), an ethylene oxide isocyanurate-modified (meth)acrylate compound (B), and a polyfunctional (meth)acrylate compound (C) having a hydroxyl group.

2. The urethane (meth)acrylate resin according to claim 1, wherein the isocyanate compound (A) is at least one compound selected from the group consisting of isocyanurate group-containing polyisocyanates, aliphatic isocyanates, aromatic isocyanates, and alicyclic structure-containing isocyanates.

3. The urethane (meth)acrylate resin according to claim 1, wherein the isocyanurate ethylene oxide modified (meth)acrylate compound (B) is a compound represented by the following formula (1). 【Chemistry 1】 [In formula (I), R １ is a hydrogen atom or -COCH=CH ２ [This indicates...]

4. The urethane (meth)acrylate resin according to claim 1, wherein the polyfunctional (meth)acrylate compound (C) is at least one compound selected from the group consisting of glycerin di(meth)acrylate, trimethylolpropane di(meth)acrylate, pentaerythritol tri(meth)acrylate, 2-hydroxy-3-methacrylpropyl(meth)acrylate, dipentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

5. The urethane (meth)acrylate resin according to claim 1, wherein the (meth)acrylic group concentration of the urethane (meth)acrylate resin is 4.0 to 8.0 mmol / g.

6. The urethane (meth)acrylate resin according to claim 1, wherein the urethane bond concentration of the urethane (meth)acrylate resin is 1.0 to 3.0 mmol / g.

7. An active energy ray curable composition comprising a urethane (meth)acrylate resin according to any one of claims 1 to 6 and a photopolymerization initiator.

8. A cured coating film which is a cured reaction product of the active energy ray curable composition described in claim 7.

9. A hard coat film comprising a cured coating film and a substrate as described in claim 8.

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