JP6845586B2 - Active energy ray-curable coating agent - Google Patents

Description

The present invention relates to an active energy ray-curable coating agent containing a mixture of urethane acrylates synthesized from pentaerythritol having different hydroxyl values.

In recent years, resins such as polyethylene terephthalate (PET) resin, polycarbonate (PC) resin, and polymethyl methacrylate (PMMA) resin have been used in many devices such as liquid crystal televisions, mobile phones, communication devices, office devices, and daily life devices, and their parts. Films and molded products are widely used in place of glass substrates and molded products. Although these resins are lighter in weight and easier to process than glass, they are inferior in weather resistance and the surface is easily scratched, so that a protective layer is generally provided. For this reason, the protective layer is required to have hardness and scratch resistance, but it is also used for bent parts such as molded products and displays, and in recent years, it has begun to be used for fortable or rollable portable display devices. Therefore, high flexibility is required. Further, when the coating agent is applied onto the film and cured, it is also required that curling is unlikely to occur due to curing shrinkage.

Conventionally, an active energy ray-curable coating agent has been used as a coating agent for a resin base material, and coating agents having various compositions have been proposed.

For example, it has one or more hydroxyl groups and an inorganic oxide selected from the group consisting of titanium oxide, zirconia, and alumina for the purpose of providing a cured product having excellent flexibility, scratch resistance, and transparency, and has an average of one or more hydroxyl groups. An active energy ray-curable resin composition containing an unsaturated monomer having a hydroxyl value of 250 to 700 mgKOH / g and having 1 to 2 (meth) acryloyl groups has been proposed (Patent Document 1).

Further, for the purpose of forming a coating film having excellent coatability and having high hardness and scratch resistance on the surface of various base materials, two or more (meth) acryloyl groups are provided in the molecule. A curable composition containing a compound, a photoradical polymerization initiator, a multi-branched polymer, and an organic solvent has been proposed (Patent Document 2).

Further, various reports have been made on an active energy ray-curable resin composition containing urethane acrylate as a coating film component and a coating film formed by using the active energy ray-curable resin composition.
For example, for the purpose of providing a cured coating film having high hardness, transparency, and less curl, a polymerizable monomer containing a monomer having a reactive double bond and an isocyanate group is polymerized. A coating active energy ray-curable resin composition containing a polymer obtained by reacting a obtained isocyanate group-containing polymer with a compound having a hydroxyl group and a (meth) acryloyl group has been proposed (Patent Document 3). ).
Further, for the purpose of simultaneously satisfying the three properties of scratch resistance, transparency and conductivity, an ultraviolet curable hard containing a conductive powder containing tin oxide as a main component and an ultraviolet curable urethane (meth) acrylate. A coating agent has been proposed (Patent Document 4).

Further, a hard coating agent containing a polyfunctional urethane acrylate having an acryloyl group, which is obtained by adding diisocyanate to a specific acrylate for the purpose of forming a coating film having excellent surface hardness, flexibility and adhesion. Is also provided (Patent Document 5).

Further, for the purpose of providing an antireflection film or sheet having excellent steel wool resistance and achieving a pencil hardness of 3H to 4H, the elastic modulus of the hard coat layer below the fracture strain is 0.7 GPa to 5 It is proposed to set it in the range of .5 GPa, and as a specific example, the hard coat layer is an ultraviolet curable resin composition composed of dipentaerythritol hexaacrylate, trimethylolpropane triacrylate and 1-hydroxycyclohexylphenyl ketone. Is disclosed (Patent Document 6).

Further, for the purpose of providing a hard coat film having less optical distortion due to a printing step, less residual air bubbles, and less denting even when a load is applied, it is hard on one surface of the transparent resin film. It has a coat layer, and a non-colored or chromatic color frame and / or an icon print layer is formed on the other surface, and the upper part of the other surface where the print layer is not formed, and A hard coat film has been proposed in which a pressure-sensitive adhesive layer obtained by curing a photocurable resin composition is laminated on the upper part of a printing layer, and a release-treated release film is bonded onto the pressure-sensitive adhesive layer. As the photocurable resin composition, a urethane acrylic photocurable pressure-sensitive adhesive composition containing a main agent composed of a urethane acrylic polymer and / or urethane acrylic, an acrylic monomer, a cross-linking agent, and a photopolymerization initiator. The use of is disclosed (Patent Document 7).

As described above, the compositions of Patent Documents 1 and 2 do not contain urethane acrylic as a coating film component. Further, the hard coating agents or resin compositions of Patent Documents 2, 3, 4, 6 and 7 do not have a problem of forming a coating film excellent in terms of flexibility, and a cured coating film excellent in this property can be obtained. It does not propose a composition for forming. Further, in the hard coating agent of Patent Document 5, since the urethane acrylate contained therein is obtained from a specific acrylate, the molecular weight thereof is usually 2700 to 4000, and the coating layer becomes thick as 15 μm or more, so that in terms of cost. Not always satisfying. Further, none of the documents deals with the technical matter of preparing a urethane acrylic by controlling the hydroxyl value of the acrylate and thereby imparting desired properties to the cured coating film.

On the other hand, urethane (meth) acrylate capable of forming a cured coating film having small curing shrinkage and being hard to curl without adding inorganic fine particles or increasing the molecular weight of the urethane (meth) acrylate compound. It is obtained by reacting the hydroxyl group of the (meth) acrylic acid adduct of pentaerythritol having a hydroxyl value of 130 mgKOH / g or more with the isocyanate group of a polyhydric isocyanate compound for the purpose of providing a resin composition containing the above. A resin composition containing a urethane (meth) acrylate is provided (Patent Document 8).
However, the cured coating film obtained from this resin composition does not have sufficient curl resistance and flexibility when pentaerythritol (meth) acrylate having a relatively low hydroxyl value is used. In addition, the hardness of the cured coating film is small, and the scratch resistance is not sufficient.

Further, when a cured coating film is formed, the activity containing urethane (meth) acrylate, which is difficult to curl due to its small curing shrinkage and can form a coating film having excellent hardness, flexibility and scratch resistance. For the purpose of providing an energy ray-curable resin composition, a pentaerythritol triacrylate having a hydroxyl value of 200 mgKOH / g or more, a dipentaerythritol pentaacrylate having a hydroxyl value of 40 mgKOH / g or more, and a polyhydric isocyanate are reacted. An active energy ray-curable resin composition containing the obtained urethane (meth) acrylate is provided (Patent Document 9). However, in the compositions of this document, pentaerythritol diacrylate and dipentaerythritol pentaacrylate are reacted together with polyvalent isocyanate to synthesize urethane (meth) acrylate, so that pentaerythritol di (meth) is relatively present. ) The content of acrylate is low, and the repeated reaction of pentaerythritol (meth) acrylate and polyhydric isocyanate is not sufficient, so only urethane acrylate with low molecular weight is produced, making it difficult to achieve both hardness and flexibility, which is fully satisfactory. I can't get the characteristics to do.

Japanese Unexamined Patent Publication No. 2018-115318 Japanese Unexamined Patent Publication No. 2009-286924 JP-A-2010-77292 Japanese Unexamined Patent Publication No. 62-170331 Japanese Unexamined Patent Publication No. 9-296152 Japanese Unexamined Patent Publication No. 2001-194504 Japanese Unexamined Patent Publication No. 2015-96333 Japanese Unexamined Patent Publication No. 2012-229412 Japanese Unexamined Patent Publication No. 2018-178094

At the above technical level, the present invention provides an active energy ray-curable coating agent capable of forming a coating layer that has both high hardness and high flexibility, is hard to curl, and has excellent transparency and scratch resistance. The purpose is to do.

The present inventors have studied an active energy ray-curable coating agent containing urethane acrylate as a coating film component, synthesized urethane acrylate from pentaerythritol acrylate having different hydroxyl values, and mixed the obtained urethane acrylate with a composition. As a result, they have found that the above-mentioned problems can be solved by a combination of specific urethane acrylates, and have reached the present invention.
That is, the present invention
[1] Urethane (meth) acrylate obtained by the reaction of pentaerythritol (meth) acrylate (a1) having a hydroxyl value of 200 to 300 mgKOH / g, polyhydric isocyanate (a2), and optionally a low-molecular-weight polyol (a3). A) and
With pentaerythritol (meth) acrylate (b1) having a hydroxyl value of 90 to 180 mgKOH / g, polyvalent isocyanate (b2), and urethane (meth) acrylate (B) obtained by the reaction of optionally a low molecular weight polyol (b3). ,
An active energy ray-curable coating agent containing inorganic fine particles (C).
[2] The active energy ray-curable coating agent according to [1], wherein the pentaerythritol (meth) acrylate having a hydroxyl value of 200 to 300 mgKOH / g contains 20 to 40% of pentaerythritol di (meth) acrylate.
[3] The urethane (meth) acrylate (A) has a molecular weight of 2,000 to 20,000, and the urethane (meth) acrylate (B) has a molecular weight of 1,000 to 5,000. [1] Alternatively, the active energy ray-curable coating agent according to [2].
[4] Of [1] to [3], the mass ratio (A / B) of the urethane (meth) acrylate (A) to the urethane (meth) acrylate (B) is 70/30 to 10/90. The active energy ray-curable coating agent according to any one.
[5] The active energy ray according to any one of [1] to [4], wherein the inorganic fine particles (C) contain reactive silica fine particles surface-treated with a silane coupling agent having a (meth) acryloyl group. Curable coating agent.
[6] The mass ratio (C / (A + B)) of the inorganic fine particles (C) to the urethane (meth) acrylate (A) and the urethane (meth) acrylate (B) is 30/100 to 350/100. The active energy ray-curable coating agent according to [5].
[7] The active energy ray-curable coating agent according to [5] or [6], wherein the inorganic fine particles (C) are contained in the active energy ray-curable coating agent in an amount of 10 to 35% by mass.
[8] The urethane (meth) acrylate (A) is contained in the active energy ray-curable coating agent in an amount of 1 to 13% by mass, and the urethane (meth) acrylate (B) is the active energy ray-curable coating agent. The active energy ray-curable coating agent according to any one of [4] to [7], which contains 4 to 13% by mass.
[9] The active energy ray-curable coating agent according to any one of [1] to [8], wherein the inorganic fine particles (C) have a particle size of 10 to 20 nm.
[10] Dipentaerythritol mono (meth) acrylate, dipentaerythritol di (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate and dipenta The following one of [1] to [9], which does not contain erythritol hexa (meth) acrylate and urethane (meth) acrylate obtained by reacting at least one of these (meth) acrylates with polyvalent isocyanate. Active energy ray-curable coating agent.
[11] The active energy ray-curable coating agent according to any one of [1] to [10], which is used for an optical film.
[12] A coating layer obtained by curing the coating agent according to any one of [1] to [10].
[13] An optical film or display device having the coating layer according to [12].
[14] A method for forming a coating layer, wherein the coating agent according to any one of [1] to [10] is applied to a target product and cured by irradiating it with active energy rays.
[15] Urethane (meth) acrylate obtained by the reaction of pentaerythritol (meth) acrylate (a1) having a hydroxyl value of 200 to 300 mgKOH / g, polyhydric isocyanate (a2), and optionally a low-molecular-weight polyol (a3). A) and
With pentaerythritol (meth) acrylate (b1) having a hydroxyl value of 90 to 180 mgKOH / g, polyvalent isocyanate (b2), and urethane (meth) acrylate (B) obtained by the reaction of optionally a low molecular weight polyol (b3). ,
A method for producing an active energy ray-curable coating agent, which is mixed with inorganic fine particles (C).

The coating layer obtained by the coating agent according to the present invention can achieve both high hardness and high flexibility, is hard to curl, and is excellent in transparency and scratch resistance.

Here, the main terms used in the present invention are defined.
The term "pentaerythritol (meth) acrylate" as used herein refers to pentaerythritol mono (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, and pentaerythritol tetra (meth) acrylate. It is used generically and includes any one of these compounds or a mixture of two or more of these compounds.
In addition, the term "dipentaerythritol (meth) acrylate" in the present specification refers to dipentaerythritol mono (meth) acrylate, dipentaerythritol di (meth) acrylate, dipentaerythritol tri (meth) acrylate, and dipentaerythritol. It is used as a generic term for tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, and dipentaerythritol hexa (meth) acrylate, and includes any one of these compounds or a mixture of two or more thereof. ..
The "hydroxyl value" in the present specification means the number of mg of potassium hydroxide corresponding to the hydroxyl group in 1 g of the sample, and the sample is phthal anhydride according to the polyether test method for polyurethane described in Japanese Industrial Standard (JIS) K1557. It is determined by esterifying with a pyridine solution of the acid and titrating the excess reagent with a sodium hydroxide solution. The terms "pentaerythritol (meth) acrylate" and "dipentaerythritol (meth) acrylate" in the present specification are a mixture of two or more kinds of pentaerythritol (meth) acrylate or a mixture of dipentaerythritol (meth) acrylate, respectively. Therefore, when referring to "pentaerythritol (meth) acrylate" or "dipentaerythritol (meth) acrylate" in the present specification, the term "hydroxyl value" means the hydroxyl value as an average value. To do. The same applies to other compounds containing hydroxyl groups.
Further, the "multivalent isocyanate" means a compound having two or more isocyanate groups in one molecule.
Further, the “isocyanate (NCO) amount” in the present specification means a value measured by a potentiometric titration device according to the JIS K 1603-1B method.
Further, the “molecular weight” in the present specification means a weight average molecular weight, and in the present specification, it means a value measured by gel permeation chromatography (GPC).
Further, the “particle size” in the present specification means a volume average particle size (Dv), and in the present specification, it means a value measured by a light scattering particle size distribution measuring device.
Further, the “viscosity” in the present specification means a value measured by a BM type viscometer according to JIS Z 8803.

Hereinafter, embodiments of the present invention will be specifically described. However, the present invention is not limited to the embodiments described below.

The coating agent of the present invention is an active energy ray-curable coating agent and contains urethane acrylate as a coating film component. In the present invention, this urethane acrylate is a urethane acrylate having a different structure (particularly, the ratio of urethane bonds in one molecule and the molecular weight are different) obtained from pentaerythritol (meth) acrylates having different high hydroxyl value and low hydroxyl value. It is characterized by being a mixture.
More specifically, urethane (meth) obtained by the reaction of pentaerythritol (meth) acrylate (a1) having a hydroxyl value of 200 to 300 mgKOH / g, polyhydric isocyanate (a2) and optionally a low molecular weight polyol (a3). Urethane (meth) obtained by the reaction of acrylate (A) with pentaerythritol (meth) acrylate (b1) having a hydroxyl value of 90 to 180 mgKOH / g, polyhydric isocyanate (b2) and optionally a low molecular weight polyol (b3). It contains a mixture with acrylate (B), which causes the above-mentioned coating properties to be exhibited.

The pentaerythritol (meth) acrylate (a1) having a hydroxyl value of 200 to 300 mgKOH / g contains a relatively high proportion of pentaerythritol di (meth) acrylate represented by the following formula (1), which is a preferred embodiment. Then, it contains 20 to 40% by mass of pentaerythritol di (meth) acrylate represented by the following formula (1).

Further, in an example of this embodiment, the pentaerythritol (meth) acrylate (a1) contains 0 to 10% by mass of pentaerythritol mono (meth) acrylate, 20 to 40% by mass of pentaerythritol di (meth) acrylate, and pentaerythritol. It contains 40 to 60% by mass of tri (meth) acrylate and 10 to 30% by mass of pentaerythritol tetra (meth) acrylate.
When the content of pentaerythritol di (meth) acrylate is high as described above, pentaerythritol (meth) acrylate and polyvalent isocyanate are repeatedly reacted to obtain urethane acrylate having a high molecular weight and a large number of urethane bonds in one molecule. It is possible to form a coating layer that is easy to be sewn and has high hardness but is particularly excellent in flexibility. When the content of pentaerythritol mono (meth) acrylate is high, more repeated reactions of pentaerythritol (meth) acrylate and multivalent isocyanate occur, but gelation is likely to occur, so this (meth) acrylate The content of is preferably small.

On the other hand, the pentaerythritol (meth) acrylate (b1) having a hydroxyl value of 90 to 180 mgKOH / g is a pentaerythritol tri (meth) acrylate represented by the following formulas (2) and (3) and / or pentaerythritol tetra (meth). ) Acrylate is contained in a relatively high proportion, and in one preferable embodiment, pentaerythritol tetra (meth) acrylate represented by the following formula (4) is contained in an amount of 30 to 50% by mass.

Further, in an example of this embodiment, the pentaerythritol (meth) acrylate (b) contains 0 to 5% by mass of pentaerythritol mono (meth) acrylate, 0 to 10% by mass of pentaerythritol di (meth) acrylate, and pentaerythritol. It contains 50 to 70% by mass of tri (meth) acrylate and 30 to 50% by mass of pentaerythritol tetra (meth) acrylate. When the content of pentaerythritol di (meth) acrylate is low as described above, the cross-linking density of the cured coating film becomes high because the pentaerythritol (meth) acrylate and the polyhydric isocyanate do not repeatedly react and the molecular weight does not increase. A coating layer having excellent hardness can be formed.

As the pentaerythritol (meth) acrylate (b1), pentaerythritol (meth) acrylate having a hydroxyl value of 100 to 170 mgKOH / g is more preferable, and pentaerythritol (meth) acrylate having a hydroxyl value of 110 to 160 mgKOH / g is particularly preferable. However, depending on the mixing ratio of the urethane acrylates (A) and (B) derived from these pentaerythritol (meth) acrylates (a1) and (b1), which will be described later, the pentaerythritol (meth) acrylates (a1) and (b1) The hydroxyl value of is adjusted.

The polyvalent isocyanate (a2) or (b2) is not particularly limited in the present invention, and examples thereof include aliphatic, alicyclic or aromatic isocyanates and polyisocyanates. Specifically, isophorone diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, triene diisocyanate, polypeptide MDI, naphthalene diisocyanate, tetramethylxylylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate methyl ester, hydrogenated xylylene diisocyanate. Isocyanate, hydrogenated diphenylmethane diisocyanate, diphenylmethane diisocyanate, methylenebis (4,1-cyclohexylene) -diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, tolylene diisocyanate (eg 2,4-tolylene diisocyanate), phenylenediisocyanate (1,4-phenylenediocyanate), diphenyldiisocyanate (eg, 4,4-diphenyldiisocyanate, 3,3-dimethyl-4,4-diphenylenediisocyanate), diphenylmethane diisocyanate (4,4-diphenylmethane diisocyanate), dicyclohexyl Methylene diisocyanate, naphthalenediocyanate (for example, 1,5-naphthalenediocyanate), xylylene diisocyanate, adduct form of diisocyanate compound and polyol compound such as trimethylolpropane, isocyanate derivatives such as biuret form and isocyanurate form of diisocyanate compound, etc. Can be mentioned. Of these, polyisocyanate derived from hexamethylene diisocyanate is preferable from the viewpoint of suppressing yellowing of the coating film. Commercial products include Duranate D-201, TPA-100, TKA-100, 24A-100, 22A-75P, P301-75E, etc. manufactured by Asahi Kasei Corporation, Coronate HX, 2715, etc. manufactured by Tosoh Corporation, Mitsui Chemicals, Inc. Company-made Takenate D160N, D-170N, D-170HN, D-172N, D-177N and the like can be used. These may be used alone or in combination of two or more.

Urethane (meth) acrylates (A) and (B) are multivalent by adding a small molecule polyol (a3) or (b3) together with pentaerythritol (meth) acrylate (a1) or (b1) as needed. It may be synthesized by reacting with isocyanate (a2) or (b2).
The polyol preferably has a solubility in water at 25 ° C. of 3.0 g / L or more, more preferably 3.5 g / L or more, more preferably 4.0 g / L or more, and in any ratio with water. Those that can be dissolved are particularly preferable.
Examples of the polyol include dihydric alcohols, trihydric alcohols, and condensates thereof. Specific examples thereof include divalents such as ethylene glycol, propylene glycol, 1,3-propanediol, and 1,3-butanediol. Alcohols such as alkylene glycols; polyalkylene glycols which are condensates of dihydric alcohols such as diethylene glycol, dipropylene glycol, polyethylene glycol and polypropylene glycol; glycerin and glycerin condensates such as glycerin, diglycerin and triglycerin; 1, Examples thereof include triols such as 2,4-butanetriol, 1,2,5-pentanetriol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, and trimethylolpropane. .. In polyethylene glycol and polypropylene glycol, the average molecular weight is preferably 2000 or less, more preferably 1000 or less, and further preferably 400 or less. Among them, ethylene glycol, propylene glycol, 1,3-butanediol, dipropylene glycol, polyethylene glycol (molecular weight 400 or less), glycerin and diglycerin are more preferable, and propylene glycol, 1,3-butanediol, dipropylene glycol and polyethylene. Glycol (molecular weight 400 or less) and glycerin are preferable.
In the present invention, a polyol having a low molecular weight (specifically, a molecular weight of 100 or less, preferably a molecular weight of 50 to 100) is preferable because it does not affect hardness and flexibility.
The content of each component in the reaction composition is not particularly limited, but is composed of pentaerythritol (meth) acrylate (a1) or (b1), polyhydric isocyanate (a2) or (b2), and a low-molecular-weight polyol (a3). ) Or (b3) is usually 40 to 82: 12 to 52.4: 0 to 9.1 ((a1) or (b1): (a2) or (b2): (a3) or ( b3)), preferably 45-80: 15-50: 0-8 ((a1) or (b1): (a2) or (b2) :( a3) or (b3)).

The reaction of pentaerythritol (meth) acrylate (a1) or (b1), polyhydric isocyanate (a2) or (b2), and optionally low-molecular-weight polyol (a3) or (b3) is a normal urethanization reaction. For example, after dissolving these compounds in an organic solvent, a catalyst, a polymerization inhibitor or the like can be appropriately added, and the reaction can be carried out by heating.
Examples of the organic solvent include aromatic hydrocarbons such as metylene, xylene and ethylbenzene; and esters or ether esters such as ethyl acetate, butyl acetate and methoxybutyl acetate; for example, monoethyl ether of diethyl ether, tetrahydrofuran and ethylene glycol. , Esters such as ethylene glycol monobutyl ether, propylene glycol monomethyl ether and diethylene glycol monoethyl ether; eg ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-butyl ketone and cyclohexanone; eg dimethyl formamide, dimethyl acetamide. , N-Methylpyrrolidone and the like; for example, sulfoxide such as dimethyl sulfoxide and the like.
Examples of the catalyst include inorganic bismuth, dioctyl tin, dibutyl tin dichloride, dibutyl tin oxide, dibutyl tin dibromide, dibutyl tin dimalate, dibutyl tin dilaurate (DBTDL), dibutyl tin diacetate, dibutyl tin sulfide, tributyl tin sulfide, and tributyl. Organic tin compounds such as tin oxide, tributyltin acetate, triethyltinethoxydo, tributyltinethoxydo, dioctyltin oxide, tributyltin chloride, tributyltin trichloroacetate, tin 2-ethylhexanoate, triethylamine, triethylenediamine, 1,8- Examples thereof include tertiary amine compounds such as diazabicyclo (5,4,0) -undecene-7 (DBU). Of these, inorganic bismuth is particularly preferable from the viewpoint of not containing tin.
From the viewpoint of preventing the C = C bond from reacting and gelling, a polymerization inhibitor may be added, for example, phenothiline, tri-p-nitrophenylmethyl, di-p-fluorophenylamine, diphenylpicri. Luhydrazil, N- (3-N-oxyanilino-1,3-dimethylbutylidene) aniline oxide, benzoquinone, hydroquinone, methylinone, butylcatechol, nitrosobenzene, picric acid, dithiobenzoyl disulfide, cuperon, copper (II) chloride And other polymerization inhibitors can be used. Metquinone is preferable from the viewpoint of the polymerization inhibitory effect. These polymerization inhibitors may be used alone or in combination of two or more.
The reaction temperature varies depending on the catalyst, but is usually 50 to 120 ° C.

In the coating agent of the present invention, the molecular weight of urethane (meth) acrylate (A) is preferably 2,000 to 20,000, more preferably 3,000 to 18,000, from the viewpoint of achieving both hardness and flexibility.
Further, from the viewpoint of compatibility with urethane acrylate (A) and hardness, the molecular weight of urethane (meth) acrylate (B) is preferably 1,000 to 5,000, more preferably 1,200 to 4,000.

The coating agent of the present invention is characterized by containing a mixture of urethane (meth) acrylate (A) and urethane (meth) acrylate (B). Urethane acrylate (A), which has a large number of urethane bonds in one molecule having a high molecular weight, has particularly excellent flexibility while having high hardness, and urethane acrylate (B), which has a low molecular weight, has a high crosslink density of a cured coating film and has a high hardness. By preparing a coating agent by mixing such urethane acrylates, it is possible to achieve both hardness and flexibility.
The mass ratio (A / B) of urethane (meth) acrylate (A) and urethane (meth) acrylate (B) is preferably 70/30 to 10/90 from the viewpoint of achieving both strength and flexibility, and is 65 /. 35 to 35/65 is more preferable, and 60/40 to 40/60 is particularly preferable.

The content of urethane (meth) acrylate (A) in the coating agent can vary over a relatively wide range, but is usually 1 to 13% by mass, preferably 8 to 12% by mass, from the viewpoint of achieving both hardness and flexibility. %. From the same point of view, the content of urethane (meth) acrylate (B) in the coating agent is usually 4 to 13% by mass, preferably 8 to 12% by mass.

The coating agent of the present invention may contain other organic coating film components as long as the effects of the present invention are not impaired.
Other organic coating components include, for example, hydroxy C _1-10 alkyl acrylate such as hydroxyethyl acrylate and polyethylene glycol (meth) clearate (n = 1 to 10) such as polyethylene glycol dimethacrylate (n = 2 to 6). ), Etc., a hydroxyl group-containing (meth) acrylate other than pentaerythritol mono, di or tri (meth) acrylate, and a urethane acrylate obtained by reacting with a polyhydric isocyanate. Commercially available products of such urethane acrylate include, for example, 8UX-145A manufactured by Taisei Fine Chemicals Co., Ltd. (adduct body obtained by reacting 2-hydroxyethyl acrylate with isophorone diisicianate).

In addition, glycerin tri (meth) acrylate, EO-modified trimethyl propantriacrylate, stearyl acrylate, ethoxy-diethylene glycol acrylate, methoxy-triethylene glucol acrylate, 2-ethylhexyl-diglucol acrylate, methoxy-polyethylene glycol acrylate, 2-ethylhexyl. -Diglucol acrylate, methoxy-polyethylene glycol acrylate, methoxydipropylene glycol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxy-polyethylene glycol acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2- Hydroxybutyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, 2-acryloyloxyethyl-succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl-phthalic acid, 2-acryloyloxy Ethyl-2-hydroxyethyl-phthalic acid, neopentyl glycol-acrylic acid-benzoic acid ester, 2-acryloyloxyethyl acid phosphate, triethylene glycol diacrylate, polyethylene glycol diacrylate, polytetramethylene glycol diacrylate , Neopentyl glycol diacrylate, 3-methyl-1.5 pentandiol diacrylate, 1.6-hexanediol diacrylate, 1.9-nonanediol diacrylate, dimethylol-tricyclodecanediacrylate, ethylene oxide addition of bisphenol A It may contain (meth) acrylate compounds such as diacrylates, propylene oxide adducts of bisphenol A diacrylates, neopentyl glycol acrylic acid adducts of hydroxypivalate, and 2-hydroxy-3-acryloyloxypropyl methacrylate. In particular, a diacrylate compound is preferable in that a cured coating film having a high crosslink density can be obtained. Examples of commercially available products of such (meth) acrylate compounds include light acrylate DCP-A (dimethylol-tricyclodecanediacrylate) manufactured by Kyoeisha Chemical Co., Ltd.

However, in a preferred embodiment of the present invention, the content of the other urethane acrylate described above is based on 100 parts by mass of the total mass of the urethane (meth) acrylate (A) and the urethane (meth) acrylate (B). , 40 parts by mass or less, preferably 36 parts by mass or less, 25% by mass or less, preferably 20% by mass or less in the coating agent. Similarly, in a preferred embodiment of the present invention, the content of the (meth) acrylate compound described above is 100 parts by mass in total, which is the mass of the urethane (meth) acrylate (A) and the urethane (meth) acrylate (B). On the other hand, it is 45 parts by mass or less, preferably 40 parts by mass or less, 30% by mass or less in the coating agent, and preferably 25% by mass or less.

In a preferred embodiment of the present invention, dipentaerythritol mono (meth) acrylate, dipentaerythritol di (meth) acrylate, dipentaerythritol tri (meth) acrylate, and dipenta are used from the viewpoint of achieving both flexibility and coating strength. It does not contain erythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, and urethane acrylate obtained from the reaction of these (meth) acrylates with polyvalent isocyanate.

The coating agent of the present invention preferably contains inorganic fine particles (C) from the viewpoint of increasing the strength of the coating film and the scratch resistance.
Examples of the inorganic fine particles (C) include silica, an organic silicic acid compound, titanium oxide, zirconia, alumina, zinc oxide and a mixture thereof. From the viewpoint of coating film strength and scratch resistance, silica, an organic silicic acid compound, zirconia or alumina is preferable, and silica, an organic silicic acid compound or alumina is preferable.
Among them, the reactive silica fine particles or the organic silicic acid compound particles surface-treated with a silane coupling agent having a (meth) acryloyl group are polymerized with urethane (meth) acrylate and coated while maintaining a high level of flexibility. It is preferable in that the film strength and scratch resistance can be increased.

Examples of such a silane coupling agent include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, and 8. -Methyloxyoctyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, etc. can be mentioned, and commercially available products include organosilica sol (MEK-AC-2140Z, MEK-AC-4130Y, MEK) manufactured by Nissan Chemical Industry Co., Ltd. -AC-5140Z, PGM-AC-2140Y, PGM-AC-4130Y, MIBK-AC-2140Z, etc.), Adeleite AT manufactured by ADEKA, ELCOM V-8802, V-8804, etc. manufactured by Nikki Catalyst Kasei Co., Ltd. .. One type of silane coupling agent may be used alone, or two or more types may be used in combination.

Examples of the organic silicon compound include hexamethyldisiloxane (HMDSO), tetramethyldisiloxane (TMDSO), 1,3-divinyltetramethyldisiloxane (DVTMDSO), hexavinyldisiloxane (HVDSO), and allyltrimethylsilane (ATMS). Allyltrimethoxysilane (ATMOS), tetraethyl orthosilicate (TEOS), trimethylsilane (TMS), triisopropylsilane (TiPS), trivinyl-trimethyl-cyclotrisiloxane (V3D3), tetravinyl-tetramethyl-cyclotetrasiloxane (V4D4) ), Tetramethylcyclotetrasiloxane (TMCS), Octamethylcyclotetrasiloxane (OMCTS), Hexamethyldisilazane (HMDSN), 2,4,6-trimethyl-2,4,6-trivinylcyclotrisilazane, Dimethylamino -Trimethylsilane (DMATMS), bis (dimethylamino) dimethylsilane (BDMAMS), tris (dimethylamino) methylsilane (TDMAMS) and the like can be mentioned.

As a commercially available product of the reactive silica fine particles, MEK-AC-2140Z (reactive silica fine particles surface-treated with a silane coupling agent having a methacryloyl group, particle diameter 10 to 20 nm, active ingredient 45%) manufactured by Nissan Chemical Co., Ltd. is used. Can be mentioned. Examples of commercially available organic silicic acid compound particles include TSUV-011A (a condensate of tetraethyl orthosilicate (TEOS) and 3-acryloxypropyltrimethoxysilane) manufactured by Taisei Fine Chemicals Co., Ltd.

The particle size (volume average particle size (Dv)) of the inorganic fine particles (C), particularly the reactive silica fine particles, is preferably 1 to 50 nm, more preferably 10 to 20 nm from the viewpoint of transparency.

The content of the inorganic fine particles (C) in the coating agent can also vary over a relatively wide range, but is usually 10 to 35% by mass, preferably 15 to 30% by mass, from the viewpoint of achieving both hardness and flexibility. Is. From the same point of view, the mass ratio (C / (A + B)) of the inorganic fine particles (C) to the urethane (meth) acrylate (A) and the urethane (meth) acrylate (B) is usually 30/100 to 350 /. It is 100, preferably 50/100 to 320/100. The content of the inorganic fine particles (C) in the total solid component of the coating agent is usually 25% by mass to 80% by mass, preferably 30% by mass to 75% by mass.

The coating agent of the present invention usually contains each of the above-mentioned components in an organic solvent.
The solvent is not particularly limited as long as it can dissolve the resin component in the coating agent of the present invention, and various organic solvents can be used. Specific examples include, for example, aromatic hydrocarbons such as toluene, xylene and ethylbenzene; eg esters or ether esters such as ethyl acetate, butyl acetate and methoxybutyl acetate; eg monoethyl ether of diethyl ether, tetrahydrofuran, ethylene glycol. , Esters such as ethylene glycol monobutyl ether, propylene glycol monomethyl ether and diethylene glycol monoethyl ether; eg, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-butyl ketone and cyclohexanone; eg, methanol, ethanol, n -And alcohols such as i-propanol, n-, i-, sec- and t-butanol, 2-ethylhexyl alcohol and benzyl alcohol; eg amides such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone; eg dimethylsulfoxide Such as sulfoxide, a mixed solvent of two or more of these, and a mixed solvent of one or more of these with water.
Of these, ethers, esters, ketones and alcohols having a boiling point of 70 to 150 ° C. are preferable from the viewpoint of storage stability and productivity, and propylene glycol monomethyl ether, ethyl acetate, methyl ethyl ketone, i-propanol and mixtures thereof are more preferable. More preferred.

The content of the solvent can vary over a wide range, but is usually 40 to 80% by mass, preferably 50 to 70% by mass in the coating agent. Further, it is usually 67 parts by mass to 400 parts by mass, preferably 100 parts by mass to 233 parts by mass with respect to 100 parts by mass of the organic coating film component. The viscosity of the coating agent is usually 5 to 500 mPa · s, preferably 10 to 100 mPa · s at the temperature at the time of use (usually 15 to 30 ° C.).
The coating agent may be diluted with a solvent in order to adjust the viscosity to an appropriate level at the time of coating, and the content of the solvent after dilution is usually 55 to 85% by mass in the coating agent, preferably 70. ~ 80% by mass.

If necessary, the coating agent of the present invention may contain other components such as a photopolymerization initiator, a leveling agent, an antioxidant and an ultraviolet absorber.

Examples of the photopolymerization initiator include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, and 2-methyl-1- (4-methylthiophenyl). ) -2-Molphorinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone, 1,2- (dimethylamino) -2-[(4-methylphenyl) Methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy -2-Methyl-1-phenyl-propane-1-one, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propane-1-one, 2-hirodoxy- 1- {4- [4- (2-Hydroxy-2-methyl-propionyl) -benzyl] phenyl} -2-methyl-propan-1-one, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, 1, 2 -Octanedione-1- (4- [phenylthio) -2- (O-benzoyloxime)], Etanone-1- (9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl]- 1- (0-acetyloxime), bis (η5-2,4-cyclopentadiene-1-yl) -bis (2,6-difluoro-3- (1H-pyrrole-1-yl) -phenyl) titanium, etc. From the viewpoint of curability, 1-hydroxy-cyclohexyl-phenyl-ketone is preferable.
The photopolymerization initiator is preferably contained in the coating agent of the present invention in the range of 0.5 to 5% by mass, more preferably in the range of 1 to 2% by mass.

Examples of the leveling agent include polydimethylsiloxane, a copolymer thereof, an acrylic polymer having a polydimethylsiloxane skeleton, a urethane polymer having a polydimethylsiloxane skeleton, and an acryloyl group or a methacryloyl group introduced therein into an active energy ray reaction. Examples thereof include silicon-based leveling agents such as compounds having imparted properties, and fluorine-based leveling agents such as perfluoroalkyl sulfonic acid, perfluoroalkyl carboxylic acid, fluorine telomer alcohol, and derivatives thereof. Examples of commercially available products include Futergent 602A manufactured by Neos Co., Ltd.
The leveling agent is preferably contained in the coating agent of the present invention in the range of 0 to 0.5% by mass, and more preferably in the range of 0.1 to 0.3% by mass.

Examples of the antioxidant include di-t-butylhydroxytoluene and 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) -1,3. 5-Triazine, pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,2-thio-diethylenebis [3- (3,5-di-t) -Butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3-( 3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N-hexamethylenebis (3, 5-di-t-butyl-4-hydroxy-hydrocinnamamide), 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene , Tris- (3,5-di-t-butyl-4-hydroxybenzyl) -isocyanurate, octylated diphenylamine, 2,4-bis [(octylthio) methyl] -O-cresol, isooctyl-3- (3) , 5-Di-t-butyl-4-hydroxyphenyl) propionate, dibutylhydroxytoluene and the like.
The antioxidant is preferably contained in the coating agent of the present invention in the range of 0 to 0.5% by mass.

Examples of the ultraviolet absorber include 2- (2-hydroxy-5-methyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, and the like. 2- (2-Hydroxy-5-t-butylphenyl) benzotriazole, 2- (2-hydroxy-3-t-butyl-5-methylphenyl) benzotriazole, 2- (2-hydroxy-3,5-t) -Butylphenyl) benzotriazole, 2- (2-hydroxy-3,5-t-butylphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazole-2-yl) -4,6-bis (1) -Methyl-1-phenylethyl) phenol, 2- (2-hydroxy-3,5-t-pentylbenzotriazole, 2- [2-hydroxy-5- (1,1,3,3, -tetramethylbutyl)) ] Bentriazole, 2- (2-hydroxy-3-s-butyl-5-t-butylbenzotriazole, 2- (2-hydroxy-3-dodecyl-5-methylbenzotriazole, 2- (2-hydroxy-3) -T-Butyl-5-methylphenyl) -5-chlorobenzotriazole, 2- (2-hydroxy-5-methylphenyl) benzotriazole, 2,2-methylenebis [4- (1,1,3,3-tetra) Methylbutyl)] -6- (2H-benzotriazole-2-yl) phenol], 3- [3- (2H-benzotriazole-2-yl) -5-t-butyl-4-hydroxyphenyl] propionate and polyethylene Glycol and the like can be mentioned.
The ultraviolet absorber is preferably contained in the coating agent of the present invention in the range of 0 to 2.0% by mass.

The coating agent of the present invention is an active energy ray-curable type, and is applied to a base material, dried if necessary, and then irradiated with active energy rays to be cured to form a coating layer.

The amount of the coating agent of the present invention applied is, for example, an amount such that the weight after drying on the substrate is 0.1 to 30 g / m ² , preferably 1 to 10 g / m ² .

The method for applying the coating agent of the present invention is not particularly limited, and a known method can be used. For example, bar coater coating, Mayer bar coating, air knife coating, gravure coating, reverse gravure coating, offset printing, flexographic printing, screen printing method and the like can be mentioned.

The active energy ray is also not particularly limited, and examples thereof include ultraviolet rays and electron beams.
When irradiating ultraviolet rays, an ultraviolet irradiation device equipped with a light source such as a high-pressure mercury lamp or a metal halide lamp can be used. The dose of ultraviolet rays is preferably an illuminance 30~2,000mW / cm ^2, a 100~1000mJ / cm ² as the accumulated light quantity. The curing atmosphere may be either an air atmosphere or an inert gas (for example, nitrogen, argon) atmosphere. A commercially available electron beam irradiation device can also be used when irradiating the electron beam, and the irradiation amount of the electron beam is preferably 1 to 10 mad.

The coating agent of the present invention can be used for various base materials, for example, polycarbonate, polymethylmethacrylate, polystyrene, polyester, polyolefin, polycycloolefin, polyimide, epoxy resin, melamine resin, triacetylcellulose resin, ABS resin. , AS resin, norbornene-based resin and the like.

With the coating agent of the present invention, the coating layer can be formed with a small coating amount as described above, and the thickness of the coating layer is usually less than 15 μm, preferably 10 μm or less, and more preferably 7 μm or less.

Further, the coating layer formed by the coating agent of the present invention is less likely to cause curl when cured by active energy rays, and is preferably applied to a film-like substrate. Further, since it is excellent in flexibility, even the coating layer existing at the corner of the molded product is unlikely to be damaged or peeled off. Therefore, it can be used for molded products having various shapes. Moreover, since it is transparent, it is particularly useful for use in molded products for optics. In particular, it is possible to achieve both high hardness and high flexibility, and by taking advantage of its excellent transparency and scratch resistance, it is a display device such as a fortable or rollable smartphone or an optical film used for such a device. Can be used for.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples. In addition, each part and% in each example is based on mass. Hereinafter, all the conditions left at room temperature unless otherwise specified are 23 ° C./55% RH.

<Preparation of urethane acrylate composition>
[Synthesis Example 1] Urethane Acrylate (A-1)
34 g of isophorone diisocyanate (a2-1) (EVENTANAT®, IPDI) manufactured by Ebonic, and a hydroxyl value of 280 mgKOH / in a 5-port flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. g pentaerythritol acrylate (a1-1) (MT-3548, manufactured by Toa Synthetic Co., Ltd., pentaerythritol diacrylate content 30%, petane erythritol monoacrylate content 5%, pentaerythritol triacrylate content Is 50%, pentaerythritol tetraacrylate content is 15%), 66 g, methyl ethyl ketone as a solvent, 0.05 g as a polymerization inhibitor, and inorganic bismuth as a catalyst (Neostan U-600, manufactured by Nitto Kasei Co., Ltd.) 0.05 g was charged and reacted at 70 ° C., and the reaction was terminated when the residual isocyanate group became 0.1% to obtain a urethane acrylate composition (solid content 70%). The weight average molecular weight of the obtained urethane acrylate (A-1) was 4800. The viscosity of the urethane acrylate composition at 25 ° C. was 400 mPa · S.

[Synthesis Example 2] Urethane Acrylate (A-2)
Hexamethylene diisocyanate (a2-2) (HDI manufactured by Tosoh Corporation) in a five-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet, and a pentaerythritol acrylate having a hydroxyl value of 280 mgKOH / g. A urethane acrylate composition was obtained in the same manner as in Synthesis Example 1 except that 72 g of (a1-1) (Tosoh MT-3548, manufactured by Asynthesis Co., Ltd.) and pentaerythritol diacrylate (content of 30%) was charged. (Solid content 70%). The weight average molecular weight of the obtained urethane acrylate (A-2) was 5,200. The viscosity of the urethane acrylate composition at 25 ° C. was 450 mPa · S.

[Synthesis Example 3] Urethane Acrylate (A-3)
A thermometer, a stirrer, a water-cooled condenser, five-necked flask equipped with a nitrogen gas blowing opening, dicyclohexylmethane diisocyanate (a2-3) (manufactured by Tokyo Chemical Industry Co., Ltd. _H 12 MDI) and 37g, hydroxyl value 280mgKOH / g The urethane acrylate composition was prepared in the same manner as in Synthesis Example 1 except that 63 g of pentaerythritol acrylate (a1-1) (MT-3548, manufactured by Toa Synthetic Co., Ltd., content of pentaerythritol diacrylate was 30%) was charged. Obtained (solid content 70%). The weight average molecular weight of the obtained urethane acrylate (A-3) was 5,500. The viscosity of the urethane acrylate composition at 25 ° C. was 360 mPa · S.

[Synthesis Example 4] Urethane Acrylate (A-4)
A bifunctional hexamethylene diisocyanate (HDI) -based prepolymer (a2-4) (Duranate D201, manufactured by Asahi Kasei Co., Ltd.) is placed in a five-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. Same as Synthesis Example 1 except that 45 g of pentaerythritol acrylate (a1-1) (MT-3548, manufactured by Toa Synthetic Co., Ltd., content of pentaerythritol diacrylate: 30%) having a hydroxyl value of 280 mgKOH / g was charged. A urethane acrylate composition was obtained (solid content 70%). The weight average molecular weight of the obtained urethane acrylate (A-4) was 15,000. The viscosity of the urethane acrylate composition at 25 ° C. was 460 mPa · S.

[Synthesis Example 5] Urethane Acrylate (A-5)
27 g of isophoron diisocyanate (a2-1) (EVENTANAT®, IPDI) manufactured by Ebonic, and a hydroxyl value of 200 mgKOH / in a 5-port flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. g pentaerythritol acrylate (a1-2) (MT-3533, manufactured by Toa Synthetic Co., Ltd., pentaerythritol diacrylate content 20%, petanerythritol monoacrylate content 5%, pentaerythritol triacrylate content A urethane acrylate composition was obtained in the same manner as in Synthesis Example 1 (solid content 70%), except that 73 g of pentaerythritol tetraacrylate was charged. The weight average molecular weight of the obtained urethane acrylate (A-5) was 4,000. The viscosity of the urethane acrylate composition at 25 ° C. was 200 mPa · S.

[Synthesis Example 6] Urethane Acrylate (A-6)
A bifunctional hexamethylene diisocyanate (HDI) -based prepolymer (a2-4) (Duranate D201, manufactured by Asahi Kasei Co., Ltd.) is placed in a five-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. Same as Synthesis Example 1 except that 54 g of pentaerythritol acrylate (a1-2) (MT-3533, manufactured by Toa Synthetic Co., Ltd., content of pentaerythritol diacrylate is 20%) having a hydroxyl value of 200 mgKOH / g was charged. A urethane acrylate composition was obtained (solid content 70%). The weight average molecular weight of the obtained urethane acrylate (A-6) was 10,000. The viscosity of the urethane acrylate composition at 25 ° C. was 400 mPa · S.

The outline of each of the above synthesis examples 1 to 6 is summarized in the table below.

Hydroxyl value 280 mgKOH / g PEA: manufactured by Toagosei Co., Ltd., MT-3548, pentaerythritol diacrylate content 30%
Hydroxyl value 200 mgKOH / g PEA: Toagosei Co., Ltd., MT-3533, pentaerythritol diacrylate content 20%
IPDI (NCO%: 37.7%): Evonik's VESTANAT (registered trademark), IPDI, isophorone diisocyanate (isocyanate amount 37.7%)
HDI (NCO%: 50%): HDI manufactured by Tosoh Corporation, hexamethylene diisocyanate (isocyanate amount 50%)
H ₁₂ MDI (NCO%: 32%): Dicyclohexylmethane diisocyanate (isocyanate amount 32%) manufactured by Tokyo Chemical Industry Co., Ltd.
D-201 (NCO%: 15.8%): Bifunctional hexamethylene diisocyanate (HDI) -based prepolymer (C-4) (Duranate D201, manufactured by Asahi Kasei Corporation)

[Synthesis Example 7] Urethane Acrylate (B-1)
17 g of isophorone diisocyanate (b2-1) (EVENTANAT®, IPDI) manufactured by Ebonic, and a hydroxyl value of 115 mgKOH / in a 5-port flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. g pentaerythritol acrylate (b1-1) (Aronix M-305, manufactured by Toa Synthetic Co., Ltd., pentaerythritol diacrylate content 0%, petane erythritol monoacrylate content 0%, pentaerythritol triacrylate content 83 g of pentaerythritol tetraacrylate (40% content), 43 g of methyl ethyl ketone as a solvent, 0.05 g of methquinone as a polymerization inhibitor, and inorganic bismuth (Neostan U-600, Nitto Kasei Co., Ltd.) as a catalyst. (Manufactured) was charged and reacted at 70 ° C., and the reaction was terminated when the residual isocyanate group became 0.1% to obtain a urethane acrylate composition (solid content 70%). The weight average molecular weight of the obtained urethane acrylate (B-1) was 1,200. The viscosity of the urethane acrylate composition at 25 ° C. was 110 mPa · S.

[Synthesis Example 8] Urethane Acrylate (B-2)
Pentaerythritol acrylate with 14 g of hexamethylene diisocyanate (b2-2) (HDI manufactured by Tosoh Corporation) and 115 mgKOH / g hydroxyl value in a 5-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. A urethane acrylate composition was obtained in the same manner as in Synthesis Example 7 (solid content 70%) except that 86 g of (b1-1) (Aronix M-305, manufactured by Toa Synthetic Co., Ltd.) was charged. The weight average molecular weight of the obtained urethane acrylate (B-2) was 1,200. The viscosity of the urethane acrylate composition at 25 ° C. was 108 mPa · S.

[Synthesis Example 9] Urethane Acrylate (B-3)
A thermometer, a stirrer, a water-cooled condenser, five-necked flask equipped with a nitrogen gas blowing opening, dicyclohexylmethane diisocyanate (b2-3) (Tokyo Chemical Industry Co., Ltd. _H 12 MDI) and 20g, hydroxyl value 115mgKOH / g A urethane acrylate composition was obtained in the same manner as in Synthesis Example 7 (solid content 70%), except that 80 g of pentaerythritol acrylate (b1-1) (Aronix M-305, manufactured by Toa Synthetic Co., Ltd.) was charged. The weight average molecular weight of the obtained urethane acrylate (B-3) was 1,200. The viscosity of the urethane acrylate composition at 25 ° C. was 110 mPa · S.

[Synthesis Example 10] Urethane Acrylate (B-4)
A bifunctional hexamethylene diisocyanate (HDI) -based prepolymer (b2-4) (Duranate D201, manufactured by Asahi Kasei Co., Ltd.) is placed in a five-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. A urethane acrylate composition was obtained in the same manner as in Synthesis Example 7 except that 67 g of pentaerythritol acrylate (b1-1) (Aronix M-305, manufactured by Toa Synthetic Co., Ltd.) having a hydroxyl value of 115 mgKOH / g was charged. Solid content 70%). The weight average molecular weight of the obtained urethane acrylate (B-4) was 3,800. The viscosity of the urethane acrylate composition at 25 ° C. was 320 mPa · S.

[Synthesis Example 11] Urethane acrylate (B-5)
22 g of isophoron diisocyanate (b2-1) (EVENTANAT®, IPDI) manufactured by Ebonic, and a hydroxyl value of 160 mgKOH / in a 5-port flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. g Pentaerythritol acrylate (b1-2) (Aronix M-306, manufactured by Toa Synthetic Co., Ltd., pentaerythritol diacrylate content 5%, petanerythritol monoacrylate content 0%, pentaerythritol triacrylate content A urethane acrylate composition was obtained in the same manner as in Synthesis Example 7 (solid content 70%) except that 78 g of pentaerythritol tetraacrylate (content of 70%) was charged. The weight average molecular weight of the obtained urethane acrylate (B-5) was 1,400. The viscosity of the urethane acrylate composition at 25 ° C. was 140 mPa · S (BM type).

[Synthesis Example 12] Urethane Acrylate (B-6)
Hexamethylene diisocyanate (b2-2) (HDI manufactured by Tosoh Corporation) in a 5-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet, and a pentaerythritol acrylate having a hydroxyl value of 160 mgKOH / g A urethane acrylate composition was obtained in the same manner as in Synthesis Example 7 (solid content 70%) except that 82 g of (b1-2) (Aronix M-306, manufactured by Toa Synthetic Co., Ltd.) was charged. The weight average molecular weight of the obtained urethane acrylate (B-6) was 1,500. The viscosity of the urethane acrylate composition at 25 ° C. was 130 mPa · S (BM type).

[Synthesis Example 13] Urethane Acrylate (B-7)
A thermometer, a stirrer, a water-cooled condenser, five-necked flask equipped with a nitrogen gas blowing opening, dicyclohexylmethane diisocyanate (b2-3) (Tokyo Chemical Industry Co., Ltd. _H 12 MDI) and 8g, hydroxyl value 160mgKOH / g The urethane acrylate composition was prepared in the same manner as in Synthesis Example 7 except that 82 g of pentaerythritol acrylate (b1-2) (Aronix M-306, manufactured by Toa Synthetic Co., Ltd., content of pentaerythritol diacrylate was 5%) was charged. Was obtained (solid content 70%). The weight average molecular weight of the obtained urethane acrylate-based composition (B-7) was 1,500. The viscosity of the urethane acrylate composition at 25 ° C. was 130 mPa · S.

The outlines of each of the above synthesis examples 7 to 13 are summarized in the table below.

Hydroxyl value 115 mgKOH / g PEA: Toagosei Co., Ltd., Aronix M-305, pentaerythritol diacrylate content 0%
Hydroxyl value 160 mgKOH / g PEA: Toagosei Co., Ltd., Aronix M-306, pentaerythritol diacrylate content 5%
IPDI (NCO%: 37.7%): Evonik's VESTANAT (registered trademark), IPDI, isophorone diisocyanate (isocyanate amount 37.7%)
HDI (NCO%: 50%): HDI manufactured by Tosoh Corporation, hexamethylene diisocyanate (isocyanate amount 50%)
H12MDI (NCO%: 32%): Dicyclohexylmethane diisocyanate (isocyanate amount 32%) manufactured by Tokyo Chemical Industry Co., Ltd.
D-201 (NCO%: 15.8%): Bifunctional hexamethylene diisocyanate (HDI) -based prepolymer (C-4) (Duranate D201, manufactured by Asahi Kasei Corporation)

[Comparative Synthesis Example 1] Urethane Acrylate (D-1)
Isophorone diisocyanate (d2-1) (Ebonic VESTANAT®, IPDI) in a 5-port flask equipped with a thermometer, agitator, water-cooled condenser, and nitrogen gas inlet, 10 g, hydroxyl value 63 mgKOH / 90 g of pentaerythritol acrylate (d1-5) (NK ester A-TMM3, manufactured by Shin-Nakamura Chemical Industry Co., Ltd., content of pentaerythritol diacrylate of 5% or less), 43 g of methyl ethyl ketone as a solvent, and methquinone as a polymerization inhibitor. , And 0.05 g of inorganic bismuth (Neostan U-600, manufactured by Nitto Kasei Co., Ltd.) as a catalyst, and the reaction was carried out at 70 ° C., and the reaction was terminated when the residual isocyanate group became 0.1%. Then, a urethane acrylate composition was obtained (solid content 70%). The weight average molecular weight of the obtained urethane acrylate (D-1) was 1,000. The viscosity of the urethane acrylate composition at 25 ° C. was 110 mPa · S.

[Comparative Synthesis Example 2] Urethane Acrylate (D-2)
A pentaerythritol acrylate containing 10 g of hexamethylene diisocyanate (d2-2) (HDI manufactured by Tosoh Corporation) and a hydroxyl value of 63 mgKOH / g in a five-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. Urethane acrylate composition in the same manner as in Comparative Synthesis Example 1 except that 90 g of (d1-5) (NK ester A-TMM3, manufactured by Shin-Nakamura Chemical Industry Co., Ltd., content of pentaerythritol diacrylate of 5% or less) was charged. A product was obtained (solid content 70%). The weight average molecular weight of the obtained urethane acrylate (D-2) was 1,000. The viscosity of the urethane acrylate composition at 25 ° C. was 105 mPa · S.

[Comparative Synthesis Example 3] Urethane Acrylate (D-3)
_{12 g of cyclohexylmethane diisocyanate (d2-3) (H 12} MDI manufactured by Tokyo Kasei Kogyo Co., Ltd.) and 63 mg KOH / g of hydroxyl value in a five-necked flask equipped with a thermometer, agitator, a water-cooled condenser, and a nitrogen gas inlet. The same as in Comparative Synthesis Example 1 except that 88 g of pentaerythritol acrylate (d1-5) (NK ester A-TMM3, manufactured by Shin-Nakamura Chemical Industry Co., Ltd., content of pentaerythritol diacrylate of 5% or less) was charged. Urethane acrylate composition was obtained (solid content 70%). The weight average molecular weight of the obtained urethane acrylate (D-3) was 1,100. The viscosity of the urethane acrylate composition at 25 ° C. was 110 mPa · S.

[Comparative Synthesis Example 4] Urethane Acrylate (D-4)
15 g of isophorone diisocyanate (d2-1) (EVENTANAT®, IPDI) manufactured by Ebonic, and a hydroxyl value of 95 mgKOH / A urethane acrylate composition was obtained in the same manner as in Comparative Synthesis Example 1 except that 85 g of dipentaerythritol acrylate (d1-6) (Aronix M-403, manufactured by Toa Synthetic Co., Ltd.) was charged (solid content 70%). ). The weight average molecular weight of the obtained urethane acrylate (D-4) was 1,800. The viscosity of the urethane acrylate composition at 25 ° C. was 160 mPa · S.

The outlines of the above comparative synthesis examples 1 to 4 are summarized in the table below.

Hydroxyl value 63 mgKOH / g PEA: Shin-Nakamura Chemical Industry Co., Ltd., NK ester A-TMM3, pentaerythritol diacrylate content 5% or less Hydroxyl value 95 mgKOH / g DPEA: Toagosei Co., Ltd., Aronix M-403
IPDI (NCO%: 37.7%): Evonik's VESTANAT (registered trademark), IPDI, isophorone diisocyanate (isocyanate amount 37.7%)
HDI (NCO%: 50%): HDI manufactured by Tosoh Corporation, hexamethylene diisocyanate (isocyanate amount 50%)
H ₁₂ MDI (NCO%: 32%): Dicyclohexylmethane diisocyanate (isocyanate amount 32%) manufactured by Tokyo Chemical Industry Co., Ltd.
D-201 (NCO%: 15.8%): Bifunctional hexamethylene diisocyanate (HDI) -based prepolymer (C-4) (Duranate D201, manufactured by Asahi Kasei Corporation)

[Comparative Synthesis Example 5] Urethane Acrylate (D-5)
26 g of isophorone diisocyanate (d2-1) (EVENTANAT®, IPDI) manufactured by Ebonic, and a hydroxyl value of 280 mgKOH / in a 5-port flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. 37 g of pentaerythritol acrylate (d1-1) (Aronix MT-3548, manufactured by Toa Synthetic Co., Ltd.) and pentaerythritol acrylate (d1-4) (Aronix M-305, manufactured by Toa Synthetic Co., Ltd.) having a hydroxyl value of 115 mgKOH / g. ), 43 g of methyl ethyl ketone as a solvent, 0.05 g of methquinone as a polymerization inhibitor, and 0.05 g of inorganic bismuth (Neostan U-600, manufactured by Nitto Kasei Co., Ltd.) as a catalyst, reacted at 70 ° C. The reaction was terminated when the isocyanate group became 0.1% to obtain a urethane acrylate composition (solid content 70%). The weight average molecular weight of the obtained urethane acrylate (D-5) was 2,400. The viscosity of the urethane acrylate composition at 25 ° C. was 180 mPa · S.

[Comparative Synthesis Example 6] Urethane Acrylate (D-6)
In a five-necked flask equipped with a thermometer, agitator, a water-cooled condenser, and a nitrogen gas inlet, 28 g of isophorone diisocyanate (d2-1) (VESTANAT®, IPDI manufactured by Ebonic) and a hydroxyl value of 280 mgKOH / 36 g of pentaerythritol acrylate (d1-1) (Aronix MT-3548, manufactured by Toa Synthetic Co., Ltd.) and pentaerythritol acrylate (d1-3) (Aronix M-306, manufactured by Toa Synthetic Co., Ltd.) having a hydroxyl value of 160 mgKOH / g. ) Was charged, and a urethane acrylate composition was obtained in the same manner as in Comparative Synthesis Example 5 (solid content 70%). The weight average molecular weight of the obtained urethane acrylate (D-6) was 2,500. The viscosity of the urethane acrylate composition at 25 ° C. was 180 mPa · S.

[Comparative Synthesis Example 7] Urethane Acrylate (D-7)
In a five-necked flask equipped with a thermometer, agitator, a water-cooled condenser, and a nitrogen gas inlet, 22 g of isophorone diisocyanate (d2-1) (VESTANAT®, IPDI manufactured by Ebonic) and a hydroxyl value of 200 mgKOH / 39 g of pentaerythritol acrylate (d1-2) (Aronix MT-3533, manufactured by Toa Synthetic Co., Ltd.) and pentaerythritol acrylate (d1-4) (Aronix M-305, manufactured by Toa Synthetic Co., Ltd.) having a hydroxyl value of 115 mgKOH / g. ) Was charged, and a urethane acrylate composition was obtained in the same manner as in Comparative Synthesis Example 5 (solid content 70%). The weight average molecular weight of the obtained urethane acrylate (D-7) was 2,000. The viscosity of the urethane acrylate composition at 25 ° C. was 150 mPa · S.

[Comparative Synthesis Example 8] Urethane Acrylate (D-8)
In a five-necked flask equipped with a thermometer, agitator, a water-cooled condenser, and a nitrogen gas inlet, 25 g of isophorone diisocyanate (d2-1) (VESTANAT®, IPDI manufactured by Ebonic), hydroxyl value 200 mgKOH / 37.5 g of pentaerythritol acrylate (d1-2) (Aronix MT-3533, manufactured by Toa Synthetic Co., Ltd.) and pentaerythritol acrylate (d1-3) with a hydroxyl value of 160 mgKOH / g (Aronix M-306, Toa Synthetic Co., Ltd.) A urethane acrylate composition was obtained in the same manner as in Comparative Synthesis Example 5 (solid content 70%), except that 37.5 g (manufactured by the company) was charged. The weight average molecular weight of the obtained urethane acrylate (D-8) was 2,200. The viscosity of the urethane acrylate composition at 25 ° C. was 150 mPa · S.

The outlines of the above comparative synthesis examples 5 to 8 are summarized in the table below.

Hydroxyl value 280 mgKOH / g PEA: manufactured by Toagosei Co., Ltd., MT-3548, pentaerythritol diacrylate content 30%
Hydroxyl value 200 mgKOH / g PEA: Toagosei Co., Ltd., MT-3533, pentaerythritol diacrylate content 20%
Hydroxyl value 160 mgKOH / g PEA: Toagosei Co., Ltd., Aronix M-306, pentaerythritol diacrylate content 5%
Hydroxyl value 115 mgKOH / g PEA: Toagosei Co., Ltd., Aronix M-305, pentaerythritol diacrylate content 0%
IPDI (NCO%: 37.7%): Evonik's VESTANAT (registered trademark), IPDI, isophorone diisocyanate (isocyanate amount 37.7%)
HDI (NCO%: 50%): HDI manufactured by Tosoh Corporation, hexamethylene diisocyanate (isocyanate amount 50%)
H ₁₂ MDI (NCO%: 32%): Dicyclohexylmethane diisocyanate (isocyanate amount 32%) manufactured by Tokyo Chemical Industry Co., Ltd.
D-201 (NCO%: 15.8%): Bifunctional hexamethylene diisocyanate (HDI) -based prepolymer (C-4) (Duranate D201, manufactured by Asahi Kasei Corporation)

<Preparation of active energy ray-curable coating agent>
(Example 1)
Obtained in [Synthesis Example 7] with 100 g of the urethane acrylate composition obtained in [Synthesis Example 1] so that the mass ratio of urethane acrylate (A-1) / urethane acrylate (B-1) is 70/30. Reactive silica fine particles (particle size 10 to 20 nm, MEK-AC-2140Z manufactured by Nissan Chemical Co., Ltd.), which was surface-treated with a silane coupling agent having a methacryloyl group, while 43.0 g of the urethane acrylate composition was placed in a beaker and stirred. 222 g (active ingredient 45%) was added and mixed, and after 10 minutes, 10.0 g of 1-hydroxycyclohexyl-phenylketone (Omnirad 184 manufactured by IGM) was added as a photopolymerization initiator, and a fluorine-based surfactant (Neos) was used as a leveling agent. 2.0 g of Futergent 602A manufactured by Co., Ltd., active ingredient 50%) was added, and stirring was continued. After confirming that the mixture was uniformly dissolved, 150.5 g of 1-methoxy-2-propanol (PGM) was added as a diluent to prepare a coating agent having a solid content of 40.0%.
At the time of coating, 289.5 g of PGM was further added to adjust the viscosity as a coating agent having a solid content of 25.8%. The coating agent was applied to a PET film (A4300 manufactured by Toyobo Co., Ltd.) with a bar coater and pre-dried at 80 ° C. for 1 minute. Next, UV irradiation was performed under air using an ultraviolet irradiation device (Light Hammer 10 manufactured by ^{Heleus Co., Ltd.) so that the irradiation amount was 500 mJ / cm 2} (illuminance 1,500 mW / cm ² ), and the PET film was subjected to ultraviolet irradiation. A coating layer having a thickness of 5 μm was prepared.

(Examples 2 to 7)
The urethane acrylate composition obtained in [Synthesis Example 1] and the urethane acrylate composition obtained in [Synthesis Example 7] were obtained so as to have the mass ratio of urethane acrylate (A-1) / urethane acrylate (B-1) shown in Table 5. Coating agents were prepared in the same manner as in Example 1 except that the urethane acrylate composition was mixed. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

Synthesis Example 1 (A-1) Composition: Urethane acrylate composition Synthesis Example 7 (A1-1) obtained by reacting isophorone diisocyanate (a2-1) with pentaerythritol acrylate (a1-1) having a hydroxyl value of 280 mgKOH / g. B-1): Urethane acrylate composition reactive silica fine particles (C-1) obtained by reacting isophorone diisocyanate (b2-1) with pentaerythritol acrylate (b1-1) having a hydroxyl value of 115 mgKOH / g: MEK-AC-2140Z (manufactured by Nissan Chemical Co., Ltd., particle size 10 to 20 nm, active ingredient 45%)
Photopolymerization initiator: 1-hydroxycyclohexyl-phenylketone (Omnirad 184 manufactured by IGM, 5 parts by mass added to 100 parts by mass of solid content)
Leveling agent: Fluorine-based surfactant (manufactured by Neos Co., Ltd., Futergent 602A, 50% active ingredient)
Diluent: 1-methoxy-2-propanol (PGM)
Silica fine particles (mass%): Content of silica fine particles with respect to the total amount (mass) of all solid components of the composition

(Examples 8 to 14)
Examples except that the urethane acrylate composition obtained in [Synthesis Example 1] and the urethane acrylate composition obtained in any of [Synthesis Example 8] to [Synthesis Example 13] were mixed in the mass ratio shown in Table 6. Coating agents were prepared in the same manner as in 1. Using the obtained coating agent, a coating film having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

Synthesis Example 1 (A-1) Composition: Urethane acrylate composition Synthesis Example 8 (A1-1) obtained by reacting isophorone diisocyanate (a2-1) with pentaerythritol acrylate (a1-1) having a hydroxyl value of 280 mgKOH / g. B-2) Composition: Urethane acrylate composition synthesis example 9 (B-3) obtained by reacting hexamethylene diisocyanate (b2-2) with pentaerythritol acrylate (b1-1) having a hydroxyl value of 115 mgKOH / g. Composition: Urethane acrylate composition synthetic example 10 (B-4) composition obtained by reacting dicyclohexylmethane diisocyanate (b2-3) with pentaerythritol acrylate (b1-1) having a hydroxyl value of 115 mgKOH / g: 2 Urethane Acrylate Composition Synthesis Example 11 (B-5) obtained by reacting a functional hexamethylene diisocyanate (b2-4) (HDI) -based prepolymer with a pentaerythritol acrylate (b1-1) having a hydroxyl value of 115 mgKOH / g. Composition: Urethane acrylate composition synthetic example 12 (B-6) composition obtained by reacting isophorone diisocyanate (b2-1) with pentaerythritol acrylate (b1-2) having a hydroxyl value of 160 mgKOH / g: Urethane acrylate composition obtained by reacting hexamethylene diisocyanate (b2-2) with pentaerythritol acrylate (b1-2) having a hydroxyl value of 160 mgKOH / g Composition Example 13 (B-7) Composition: Dicyclohexylmethane diisocyanate ( Urethane acrylate composition reactive silica fine particles (C-1) obtained by reacting b2-3) with pentaerythritol acrylate (b1-2) having a hydroxyl value of 160 mgKOH / g: MEK-AC-2140Z (Nissan Chemical Co., Ltd.) Made by the company, particle size 10 to 20 nm, active ingredient 45%)
Photopolymerization initiator: 1-hydroxycyclohexyl-phenylketone (Omnirad 184 manufactured by IGM, 5 parts by mass added to 100 parts by mass of solid content)
Leveling agent: Fluorine-based surfactant (manufactured by Neos Co., Ltd., Futergent 602A, 50% active ingredient)
Diluent: 1-methoxy-2-propanol (PGM)
Silica fine particles (mass%): Content of silica fine particles with respect to the total amount (mass) of all solid components of the composition

(Examples 15 to 18)
[Synthesis Example 2] so that the mass ratio of urethane acrylate (A-2) / urethane acrylate (B-1), (B-3), (B-6) or (B-7) is 50/50. 71.4 g of the urethane acrylate composition obtained in the above was mixed with 71.4 g of the urethane acrylate composition obtained in [Synthesis Example 7], [Synthesis Example 9], [Synthesis Example 12] or [Synthesis Example 13]. A coating agent was prepared in the same manner as in Example 1 except for the above. Using each of the obtained coating agents, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

(Example 19)
71.4 g of the urethane acrylate composition obtained in [Synthesis Example 3] and [Synthesis Example 7] so that the mass ratio of urethane acrylate (A-3) / urethane acrylate (B-1) is 50/50. A coating agent was prepared in the same manner as in Example 1 except that 71.4 g of the obtained urethane acrylate composition was mixed. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

(Example 20)
71.4 g of the urethane acrylate composition obtained in [Synthesis Example 4] and [Synthesis Example 8] so that the mass ratio of urethane acrylate (A-4) / urethane acrylate (B-2) is 50/50. A coating agent was prepared in the same manner as in Example 1 except that 71.4 g of the obtained urethane acrylate composition was mixed. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

(Example 21)
71.4 g of the urethane acrylate composition obtained in [Synthesis Example 5] and [Synthesis Example 9] so that the mass ratio of urethane acrylate (A-5) / urethane acrylate (B-3) is 50/50. A coating agent was prepared in the same manner as in Example 1 except that 71.4 g of the obtained urethane acrylate composition was mixed. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

(Example 22)
71.4 g of the urethane acrylate composition obtained in [Synthesis Example 6] and [Synthesis Example 10] were used so that the mass ratio of urethane acrylate (A-6) / urethane acrylate (B-4) was 50/50. A coating agent was prepared in the same manner as in Example 1 except that 71.4 g of the obtained urethane acrylate composition was mixed. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.
The outlines of Examples 15 to 22 are summarized below.

Synthesis Example 2 (A-2) Composition: Urethane acrylate composition Synthesis Example 3 (A1-2) obtained by reacting hexamethylene diisocyanate (a2-2) with pentaerythritol acrylate (a1-1) having a hydroxyl value of 280 mgKOH / g. A-3) Composition: Urethane acrylate composition synthesis example 4 (A-4) obtained by reacting dicyclohexamethylene diisocyanate (a2-3) with pentaerythritol acrylate (a1-1) having a hydroxyl value of 280 mgKOH / g. Composition: Urethane acrylate composition synthesis example 5 obtained by reacting a bifunctional hexamethylene diisocyanate (HDI) -based prepolymer (a2-4) with a pentaerythritol acrylate (a1-1) having a hydroxyl value of 280 mgKOH / g. (A-5) Composition: Urethane acrylate composition synthesis example 6 (A-6) obtained by reacting isophoron diisocyanate (a2-1) with pentaerythritol acrylate (a1-2) having a hydroxyl value of 200 mgKOH / g. ) Composition: An example of synthesizing a urethane acrylate composition obtained by reacting a bifunctional hexamethylene diisocyanate (HDI) -based prepolymer (a2-4) with a pentaerythritol acrylate (a1-2) having a hydroxyl value of 200 mgKOH / g. 7 (B-1) Composition: Urethane Acrylate Composition Synthesis Example 8 (B-) obtained by reacting isophorone diisocyanate (b2-1) with pentaerythritol acrylate (b1-1) having a hydroxyl value of 115 mgKOH / g. 2) Composition: Composition of Urethane Acrylate Composition Synthesis Example 9 (B-3) obtained by reacting hexamethylene diisocyanate (b2-2) with pentaerythritol acrylate (b1-1) having a hydroxyl value of 115 mgKOH / g. : Urethane acrylate composition obtained by reacting dicyclohexylmethane diisocyanate (b2-3) with pentaerythritol acrylate (b1-1) having a hydroxyl value of 115 mgKOH / g Composition Example 10 (B-4) Composition: Bifunctional Composition of Urethane Acrylate Composition Synthesis Example 11 (B-5) obtained by reacting hexamethylene diisocyanate (b2-4) (HDI) -based prepolymer with pentaerythritol acrylate (b1-1) having a hydroxyl value of 115 mgKOH / g. Product: Obtained by reacting isophoron diisocyanate (b2-1) with pentaerythritol acrylate (b1-2) having a hydroxyl value of 160 mgKOH / g. Urethane Acrylate Composition Synthesis Example 12 (B-6) Composition: Urethane acrylate obtained by reacting hexamethylene diisocyanate (b2-2) with pentaerythritol acrylate (b1-2) having a hydroxyl value of 160 mgKOH / g. Composition Synthesis Example 13 (B-7) Composition: Urethane acrylate composition reactivity obtained by reacting dicyclohexylmethane diisocyanate (b2-3) with pentaerythritol acrylate (b1-2) having a hydroxyl value of 160 mgKOH / g. Silica fine particles (C-1): MEK-AC-2140Z (manufactured by Nissan Chemical Co., Ltd., particle size 10 to 20 nm, active ingredient 45%)
Photopolymerization initiator: 1-hydroxycyclohexyl-phenylketone (Omnirad 184 manufactured by IGM, 5 parts by mass added to 100 parts by mass of solid content)
Leveling agent: Fluorine-based surfactant (manufactured by Neos Co., Ltd., Futergent 602A, 50% active ingredient)
Diluent: 1-methoxy-2-propanol (PGM)
Silica fine particles (mass%): Content of silica fine particles with respect to the total amount (mass) of all solid components of the composition

(Example 23)
411 g of reactive silica fine particles (C-1) (particle size 10 to 20 nm, dispersed in methyl ethyl ketone, MEK-AC-2140Z manufactured by Nissan Chemical Co., Ltd., active ingredient 45%) surface-treated with a silane coupling agent having a methacryloyl group. In addition, 174 g of 1-methoxy-2-propanol (PGM) was added to prepare a coating agent having a solid content of 40.0%, and at the time of coating, 407 g of PGM was further added to prepare a coating agent having a solid content of 25.8%. A coating agent was prepared in the same manner as in Example 3 except that the viscosity was adjusted as the coating agent of. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on the PET film in the same manner as in Example 1.

(Example 24)
Add 667 g of reactive silica fine particles (C-1) (MEK-AC-2140Z, manufactured by Nissan Chemical Co., Ltd., particle size 10 to 20 nm, dispersed in methyl ethyl ketone) surface-treated with a silane coupling agent having a methacryloyl group, and 1-. 206 g of methoxy-2-propanol (PGM) was developed to prepare a coating agent having a solid content of 40.0%, and at the time of coating, 565 g of PGM was further added to prepare a coating agent having a solid content of 25.8%. A coating agent was prepared in the same manner as in Example 3 except that the viscosity was adjusted. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

(Example 25)
Reactive silica fine particles (C-2) surface-treated with a silane coupling agent having a methacryloyl group (PGM-AC-2140Y, manufactured by Nissan Chemical Industries, Ltd., dispersed in 1-methoxy-2-propanol, particle diameter 10 to 20 nm) A coating agent was prepared in the same manner as in Example 3 except that 222 g was added. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

(Example 26)
Tetraethyl orthosilicate with 111 g of reactive silica fine particles (C-1) (MEK-AC-2140Z, manufactured by Nissan Chemical Co., Ltd., particle size 10 to 20 nm, dispersed in methyl ethyl ketone) surface-treated with a silane coupling agent having a methacryloyl group. A coating agent was prepared in the same manner as in Example 3 except that 111 g of a condensate of (TEOS) and 3-acryloxypropyltrimethoxysilane (TSUV-011A manufactured by Taisei Fine Chemicals Co., Ltd.) was added. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

(Example 27)
With 71.4 g of the urethane acrylate composition of [Synthesis Example 1] and 71.4 g of the urethane acrylate composition of [Synthesis Example 7], an adduct of 2 hydroxyethyl acrylate and isophorone diisocyanate (manufactured by Taisei Fine Chemical Co., Ltd., 8UX-145A) ) 50 g is placed in a beaker, 225 g of 1-methoxy-2-propanol (PGM) is added to prepare a coating agent having a solid content of 40.0%, and 359 g of PGM is further added at the time of coating to solidify. A coating agent was prepared in the same manner as in Example 3 except that the viscosity was adjusted as a coating agent having a portion of 25.8%. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on the PET film in the same manner as in Example 1.

(Example 28)
Dimethylol-tricyclodecanediacrylate (Light Acrylate DCP-A, manufactured by Kyoeisha Chemical Co., Ltd.) 50 g together with 71.4 g of the urethane acrylate composition of [Synthesis Example 1] and 71.4 g of the urethane acrylate composition of [Synthesis Example 7]. To prepare a coating agent having a solid content of 40.0% by adding 225 g of 1-methoxy-2-propanol (PGM) to a beaker, and further adding 359 g of PGM at the time of coating to have a solid content of 25. The coating agent was adjusted in the same manner as in Example 3 except that the viscosity was adjusted as an 8% coating agent. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on the PET film in the same manner as in Example 1.
The outlines of Examples 23 to 28 are summarized in the table below.

Synthesis Example 1 (A-1) Composition: Urethane acrylate composition Synthesis Example 7 (A1-1) obtained by reacting isophorone diisocyanate (a2-1) with pentaerythritol acrylate (a1-1) having a hydroxyl value of 280 mgKOH / g. B-1) Composition: Urethane acrylate composition obtained by reacting isophorone diisocyanate (b2-1) with pentaerythritol acrylate (b1-1) having a hydroxyl value of 115 mgKOH / g Bifunctional urethane acrylate: 8UX-145A , Taisei Fine Chemical Co., Ltd. Dimethylol-Tricyclodecanediacrylate: Light Acrylate DCP-A, Kyoeisha Chemical Co., Ltd.)
Reactive silica fine particles (C-1): MEK-AC-2140Z (particle diameter 10-20 nm, manufactured by Nissan Chemical Industries, Ltd., active ingredient 45%)
Reactive silica fine particles (C-2): PGM-AC-2140Y (particle diameter 10-20 nm, manufactured by Nissan Chemical Industries, Ltd., active ingredient 45%)
Reactive silica fine particles (C-3): TSUV-011A (condensate of TEOS manufactured by Taisei Fine Chemicals Co., Ltd. and KBM-5103 (3-acryloxypropyltrimethoxysilane), active ingredient 45%)
Silica fine particles (mass%): Content of silica fine particles with respect to the total amount (mass) of all solid components of the composition

(Comparative Example 1)
The urethane acrylate composition obtained in [Synthesis Example 1] and the urethane acrylate composition obtained in [Synthesis Example 7] were obtained so that the mass ratio of urethane acrylate (A-1) / urethane acrylate (B-1) was 90/10. A coating agent was prepared in the same manner as in Example 1 except that the urethane acrylate composition was mixed. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

(Comparative Example 2)
The urethane acrylate composition obtained in [Synthesis Example 1] and the urethane acrylate composition obtained in [Synthesis Example 7] were obtained so that the mass ratio of urethane acrylate (A-1) / urethane acrylate (B-1) was 80/20. A coating agent was prepared in the same manner as in Example 1 except that the urethane acrylate composition was mixed. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on the PET film in the same manner as in Example 1.

(Comparative Examples 3 to 6)
The same as in Example 1 except that the urethane acrylate composition obtained in [Synthesis Example 1] and the urethane acrylate composition obtained in any of [Comparative Synthesis Example 1] to [Comparative Synthesis Example 4] were mixed. , A coating agent was prepared. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

(Comparative Example 7)
Dipentaerythritol hexaacrylate (A-, manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) together with 71.4 g of the urethane acrylate composition obtained in [Synthesis Example 1] and 71.4 g of the urethane acrylate composition obtained in [Synthesis Example 7]. 50 g of DPH) is mixed, and 225 g of 1-methoxy-2-propanol (PGM) is added to prepare a coating agent having a solid content of 40.0%. At the time of coating, an additional 359 g of PGM is added to solidify. A coating agent was prepared in the same manner as in Example 1 except that the viscosity was adjusted as a coating agent having a portion of 25.8%. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

(Comparative Example 8)
44 g (45% active ingredient) of reactive silica fine particles (C-1) (MEK-AC-2140Z, manufactured by Nissan Chemical Co., Ltd., particle diameter 10 to 20 nm) surface-treated with a silane coupling agent having a methacryloyl group are mixed. , 1-methoxy-2-propanol (PGM) was added in an amount of 128 g to prepare a coating agent having a solid content of 40.0%, and at the time of coating, 379 g of PGM was further added to have a solid content of 25.8%. A coating agent was prepared in the same manner as in Example 3 except that the viscosity was adjusted as the coating agent. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on the PET film in the same manner as in Example 1.

(Comparative Example 9)
Prepared without adding reactive silica fine particles (C-1) (MEK-AC-2140Z, manufactured by Nissan Chemical Co., Ltd., particle diameter 10 to 20 nm) surface-treated with a silane coupling agent having a methacryloyl group, 1-methoxy. -2-propanol (PGM) was added in an amount of 123 g to prepare a coating agent having a solid content of 40.0%, and at the time of coating, 153 g of PGM was further added to prepare a coating agent having a solid content of 25.8%. A coating agent was prepared in the same manner as in Example 3 except that the above was adjusted. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on the PET film in the same manner as in Example 1.

(Comparative Example 10)
Other than using 142.8 g of the urethane acrylate composition obtained in [Synthesis Example 5] instead of the urethane acrylate composition obtained in [Synthesis Example 1] and the urethane acrylate composition obtained in [Synthesis Example 7]. Prepared a coating agent in the same manner as in Example 1. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

(Comparative Example 11)
Other than using 142.8 g of the urethane acrylate composition obtained in [Synthesis Example 11] instead of the urethane acrylate composition obtained in [Synthesis Example 1] and the urethane acrylate composition obtained in [Synthesis Example 7]. Prepared a coating agent in the same manner as in Example 1. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.
The outlines of Comparative Examples 1 to 11 are summarized below.

Synthesis Example 1 (A-1) Composition: Urethane acrylate composition synthesis example 5 (A1-1) obtained by reacting isophorone diisocyanate (a2-1) with pentaerythritol acrylate (a1-1) having a hydroxyl value of 280 mgKOH / g. A-5) Composition: Urethane acrylate composition synthesis example 7 (B-1) obtained by reacting isophorone diisocyanate (a2-1) with pentaerythritol acrylate (a1-2) having a hydroxyl value of 200 mgKOH / g. : Isophoron diisocyanate (b2-1) is reacted with pentaerythritol acrylate (b1-1) having a hydroxyl value of 115 mgKOH / g to obtain a urethane acrylate composition Synthesis Example 11 (B-5): Isophoron diisocyanate (b2). Comparative Synthesis Example 1 (D-1): Isophoron diisocyanate (d2-1) of a urethane acrylate composition obtained by reacting -1) with a pentaerythritol acrylate (b1-2) having a hydroxyl value of 160 mgKOH / g. Comparative Synthesis Example 2 (D-2): Hexamethylene diisocyanate (d2-2) of a urethane acrylate composition obtained by reacting with a pentaerythritol acrylate (d1-1) having a hydroxyl value of 63 mgKOH / g, and a hydroxyl value of 63 mgKOH / g. Comparative Synthesis Example 3 (D-3): Cyclohexylmethane Diisocyanate (d2-3) obtained by reacting g pentaerythritol acrylate (d1-1) with pentaerythritol acrylate having a hydroxyl value of 63 mgKOH / g. Comparative Synthesis Example 4 (D-4) of Urethane Acrylate Composition Obtained by Reacting with (d1-1): Isophoron diisocyanate (d2-1) was mixed with dipentaerythritol acrylate (d1-2) having a hydroxyl value of 95 mgKOH / g. ), A urethane acrylate composition obtained by reacting with dipentaerythritol hexaacrylate: NK ester DPH (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.)
Reactive silica fine particles (C-1): MEK-AC-2140Z (manufactured by Nissan Chemical Industries, Ltd., particle size 10 to 20 nm, active ingredient 45%)
Photopolymerization initiator: 1-hydroxycyclohexyl-phenylketone (Omnirad 184 manufactured by IGM, 5 parts by mass added to 100 parts by mass of solid content)
Leveling agent: Fluorine-based surfactant (manufactured by Neos Co., Ltd., Futergent 602A, 50% active ingredient)
Diluent: 1-methoxy-2-propanol (PGM)
Silica fine particles (mass%): Content of silica fine particles with respect to the total amount (mass) of all solid components of the composition

(Comparative Examples 12 to 15)
It was obtained in any of [Comparative Synthesis Example 5] to [Comparative Synthesis Example 8] instead of the urethane acrylate composition obtained in [Synthesis Example 1] and the urethane acrylate composition obtained in [Synthesis Example 7]. A coating agent was prepared in the same manner as in Example 1 except that 142.8 g of the urethane acrylate composition was used. Using the obtained coating agent, a coating layer having a film thickness of 5 μm was prepared on each PET film in the same manner as in Example 1.

Comparative Synthesis Example 5 (D-5) Composition: Isophorone diisocyanate (d1-1) having a hydroxyl value of 280 mgKOH / g and pentaerythritol acrylate (d1-4) having a hydroxyl value of 115 mgKOH / g are used together. Comparative Synthesis Example 6 (D-6) Composition of Urethane Acrylate Composition Obtained by Reacting with a2-1): Pentaerythritol acrylate (d1-1) having a hydroxyl value of 280 mgKOH / g and penta with a hydroxyl value of 160 mgKOH / g Urethane acrylate composition comparative synthesis example 7 (D-7) obtained by reacting erythritol acrylate (d1-3) together with isophorone diisocyanate (a2-1): pentaerythritol acrylate having a hydroxyl value of 200 mgKOH / g ( Comparative Synthesis Example 8 (D-) of a urethane acrylate composition obtained by reacting d1-2) and pentaerythritol acrylate (d1-4) having a hydroxyl value of 115 mgKOH / g together with isophorone diisocyanate (a2-1). 8): Obtained by reacting pentaerythritol acrylate (d1-2) having a hydroxyl value of 200 mgKOH / g and pentaerythritol acrylate (d1-3) having a hydroxyl value of 160 mgKOH / g together with isophorone diisocyanate (a2-1). Urethane Acrylate Composition Reactive Silica Fine Particles (C-1): MEK-AC-2140Z (manufactured by Nissan Chemical Co., Ltd., particle size 10 to 20 nm, active ingredient 45%)
Photopolymerization initiator: 1-hydroxycyclohexyl-phenylketone (Omnirad 184 manufactured by IGM, 5 parts by mass added to 100 parts by mass of solid content)
Leveling agent: Fluorine-based surfactant (manufactured by Neos Co., Ltd., Futergent 602A, 50% active ingredient)
Diluent: 1-methoxy-2-propanol (PGM)
Silica fine particles (mass%): Content of silica fine particles with respect to the total amount (mass) of all solid components of the composition

<Evaluation of physical properties of cured coating film>
The following physical property evaluations were carried out for the coating layers prepared in each Example and Comparative Example.

[1. Pencil hardness of cured coating film]
In accordance with JIS K 5600-5-4 (1999), a pencil scratch test was carried out on the coated surface of the base material on which the coating layer was formed under a load of 750 g, and the evaluation was made according to the following criteria.
4H or more ◎
3H 〇 2H △
H or less ×

[2. Flexibility of the cured coating film]
Flexibility was evaluated using a cylindrical mandrel bending tester according to JIS K 5600-5-1.
When the cured coating film for evaluation was wound around a test rod so that the coating film surface was on the outside, the maximum diameter (integer value, mm) at which cracking or peeling occurred was measured. The smaller the value, the higher the flexibility of the coating film.
6 or more -10 mm or less ◎
10 or more -14 mm or less 〇 15 or more -20 mm or less △
20 mm or more ×

[3. SW resistance of cured coating film]
Using steel wool (Bonster # 0000, manufactured by Nippon Steel Wool Co., Ltd.), the surface of the cured coating film was reciprocated 10 times while applying a load of 500 g, and then the degree of damage to the surface was visually observed.
◎ No change in appearance 〇Several scratches △ 10 scratches × Whitening

[4. Transparency of cured coating film]
The haze value of the substrate with a coating film was measured using a haze meter (NDH-5000, manufactured by Nippon Denshoku Industries Co., Ltd.) in accordance with JIS K 7136 (2000).
◎ Less than 0.1% 〇 0.1% or more and less than 0.5% △ 0.5% or more and less than 1%

[5. Curling resistance of cured coating film]
The film on which the coating layer was formed was cut into 10 cm squares and evaluated by the total floating of the four corners.
◎ 0 to less than 10 mm 〇 10 to less than 20 mm △ 20 to less than 30 mm x 30 mm or more

The evaluation results are summarized below.

As can be understood from the results shown in Table 11, the composition of urethane acrylate (A-1 to A-6) having a relatively high molecular weight synthesized from pentaerythritol triacrylate having a high hydroxyl value (200 mgKOH / g or 280 mgKOH / g). Examples 1 to 1 in which a composition of urethane acrylate having a relatively low molecular weight (B-1 to B-7) synthesized from pentaerythritol triacrylate having a hydroxyl value of 115 or 160 mgKOH / g and reactive silica fine particles are mixed. The coating layer formed of the coating agent of No. 28 formed a transparent cured coating film having low curing shrinkage and no curling, achieving both high flexibility and high hardness, and excellent scratch resistance.
On the other hand, the coating layer formed with the coating agents of Comparative Examples 1 and 2 having a high mass ratio of urethane acrylate synthesized from pentaerythritol triacrylate having a high hydroxyl value (200 mgKOH / g or 280 mgKOH / g) was inferior in hardness. became. Further, the coating layer formed with the coating agents of Comparative Examples 3 to 5 containing the urethane acrylate obtained from pentaerythritol acrylate (d1-5) having a hydroxyl value of 63 mgKOH / g had a high crosslink density and deteriorated flexibility. A coating layer formed with a coating agent of Comparative Example 6 containing a urethane acrylate obtained from dipentaerythritol pentaacrylate (d1-6) having a hydroxyl value of 95 mgKOH / g, and a coating of Comparative Example 7 containing dipentaerythritol hexaacrylate. In both of the coating layers formed with the agent, the crosslink density was high and the flexibility was deteriorated. The transparency of the coating layer formed with the coating agent of Comparative Example 8 in which the amount of the reactive silica fine particles was significantly reduced was deteriorated. It is presumed that the compatibility between the reactive silica fine particles and the urethane acrylate-based composition deteriorated. Further, the coating layer formed with the coating agent of Comparative Example 9 which did not contain the reactive silica fine particles did not have sufficient hardness. The coating agent of Comparative Example 10 containing only urethane acrylate (A-5) synthesized from pentaerythritol triacrylate having a high hydroxyl value (200 mgKOH / g) as an organic coating film component has a crosslink density because it is only urethane acrylate having a relatively high molecular weight. The result was that the hardness and SW resistance were inferior. The coating agent of Comparative Example 11 containing only urethane acrylate (B-5) synthesized from pentaerythritol triacrylate having a hydroxyl value (160 mgKOH / g) as an organic coating film component has a large curing shrinkage because it is only urethane acrylate having a low molecular weight. The result was that the flexibility and curl resistance were inferior.
Obtained by reacting pentaerythritol acrylates having two different hydroxyl values (any two of 280 mgKOH / g, 115 mgKOH / g, 200 mgKOH / g, and 160 mgKOH / g) with isophorone diisocyanate (a2-1). The coating layer formed by the coating agents of Comparative Examples 12 to 15 containing the urethane acrylate was not satisfactory in pencil hardness, mandrel flexibility, SW resistance, and curl resistance. Although not bound by theory, in these coating agents, urethane acrylates are synthesized by reacting petane erythritol with different hydroxyl values together, so the resulting urethane acrylate is relatively pentaerythritol di (meth). Since the content of urethane acrylate obtained from acrylate is low and the repeated reaction between pentaerythritol (meth) acrylate and polyhydric isocyanate is not sufficient, only urethane acrylate with low molecular weight is produced, making it difficult to achieve both hardness and flexibility. It is presumed that it became.

The coating layer obtained by the coating agent according to the present invention is less likely to cause curl, can achieve both high hardness and high flexibility, and is also excellent in transparency and scratch resistance. Therefore, it is a coating for hard coating of various products. It is useful as an agent, especially as a coating agent for optical films. In particular, it is expected to be used in display devices such as fortable or rollable smartphones. It is also useful as a paint, ink, resist and the like.

Claims (14)

With pentaerythritol (meth) acrylate (a1) having a hydroxyl value of 200 to 300 mgKOH / g, polyhydric isocyanate (a2), and urethane (meth) acrylate (A) obtained by the reaction of optionally a low molecular weight polyol (a3). ,
With pentaerythritol (meth) acrylate (b1) having a hydroxyl value of 90 to 180 mgKOH / g, polyvalent isocyanate (b2), and urethane (meth) acrylate (B) obtained by the reaction of optionally a low molecular weight polyol (b3). ,
And a inorganic fine particles (C),
An active energy ray-curable coating agent having a mass ratio (A / B) of the urethane (meth) acrylate (A) to the urethane (meth) acrylate (B) of 70/30 to 10/90. The active energy ray-curable coating agent according to claim 1, wherein the pentaerythritol (meth) acrylate having a hydroxyl value of 200 to 300 mgKOH / g contains 20 to 40% of pentaerythritol di (meth) acrylate. Claim 1 or 2, wherein the urethane (meth) acrylate (A) has a molecular weight of 2,000 to 20,000, and the urethane (meth) acrylate (B) has a molecular weight of 1,000 to 5,000. The active energy ray-curable coating agent described. The active energy ray-curable coating agent according to any one of claims 1 to 3 , wherein the inorganic fine particles (C) contain reactive silica fine particles surface-treated with a silane coupling agent having a (meth) acryloyl group. .. Claimed that the mass ratio (C / (A + B)) of the inorganic fine particles (C) to the urethane (meth) acrylate (A) and the urethane (meth) acrylate (B) is 30/100 to 350/100. Item 4. The active energy ray-curable coating agent according to Item 4. The active energy ray-curable coating agent according to claim 4 or 5 , wherein the inorganic fine particles (C) are contained in the active energy ray-curable coating agent in an amount of 10 to 35% by mass. The urethane (meth) acrylate (A) is contained in the active energy ray-curable coating agent in an amount of 1 to 13% by mass, and the urethane (meth) acrylate (B) is contained in the active energy ray-curable coating agent (4). The active energy ray-curable coating agent according to any one of claims 1 to 6 , which contains ~ 13% by mass. The active energy ray-curable coating agent according to any one of claims 1 to 7 , wherein the inorganic fine particles (C) have a particle size of 10 to 20 nm. Dipentaerythritol mono (meth) acrylate, dipentaerythritol di (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, dipentaerythritol hexa ( The active energy ray curing according to any one of claims 1 to 8 , which does not contain a meta) acrylate and a urethane (meth) acrylate obtained by reacting at least one of these (meth) acrylates with a polyvalent isocyanate. Mold coating agent. The active energy ray-curable coating agent according to any one of claims 1 to 9 , which is used for an optical film. A coating layer obtained by curing the coating agent according to any one of claims 1 to 9. An optical film or display device having the coating layer according to claim 11. A method for forming a coating layer, wherein the coating agent according to any one of claims 1 to 9 is applied to a target product and cured by irradiating the target product with active energy rays. With pentaerythritol (meth) acrylate (a1) having a hydroxyl value of 200 to 300 mgKOH / g, polyhydric isocyanate (a2), and urethane (meth) acrylate (A) obtained by the reaction of optionally a low molecular weight polyol (a3). ,
With pentaerythritol (meth) acrylate (b1) having a hydroxyl value of 90 to 180 mgKOH / g, polyvalent isocyanate (b2), and urethane (meth) acrylate (B) obtained by the reaction of optionally a low molecular weight polyol (b3). ,
A method for producing an active energy ray-curable coating agent that mixes with inorganic fine particles (C).
A method in which the mass ratio (A / B) of the urethane (meth) acrylate (A) to the urethane (meth) acrylate (B) is 70/30 to 10/90 .