TW201636380A - Active-energy-ray-curable composition, active-energy-ray-curable adhesive composition, adhesive, adhesive sheet, and novel urethane (meth)acrylate - Google Patents

Abstract

The purpose of the present invention is to provide an active-energy-ray-curable composition containing a urethane (meth)acrylate having a low dielectric constant and excellent compatibility. The present invention relates to an active-energy-ray-curable composition containing a urethane (meth)acrylate (A) which is a product of reaction of a polyester-based polyol (a1), a polyisocyanate (a2), and a hydroxyl-group-containing (meth)acrylate (a3), the dielectric constant of the urethane (meth)acrylate (A) being 7.0 or less.

Description

Active energy ray-curable composition, active energy ray-curable adhesive composition, adhesive and adhesive sheet, and novel urethane (meth) acrylate

The present invention relates to an active energy ray-curable composition, an active energy ray-curable pressure-sensitive adhesive composition containing the same, and a binder and a pressure-sensitive adhesive sheet using the active energy ray-curable pressure-sensitive adhesive composition. Specifically, the active energy ray-curable composition contains a urethane (meth) acrylate having a low dielectric constant and excellent compatibility.

Moreover, the invention also relates to novel urethane (meth) acrylates.

In the adhesive, there are various types of adhesives such as a strong adhesive which is strongly bonded to the adherend for a long period of time, or a peeling type adhesive which is premised on peeling off from the adhered body. The form is used for individually designing the most suitable adhesive for various fields.

Conventionally, as a binder for a display member, an electronic component, and an optical material, for example, an aminocarboxylic acid obtained by reacting a polyol with a polyisocyanate and a hydroxyl group-containing (meth) acrylate is known. An ester (meth) acrylate, which is cured by irradiation with an active energy ray. As the polyol, a polyester-based polyol obtained by condensing a polyvalent carboxylic acid with a polyvalent alcohol is known, and adipic acid is used as the carboxylic acid (for example, see Patent Document 1).

In recent years, in particular, in optical component applications, and more particularly in touch panel applications, in addition to adhesiveness and heat and humidity resistance, in order to suppress malfunction of the touch panel caused by noise generated by the display member and other peripheral components, A binder with a low dielectric constant is required.

For example, a resin composition for an ultraviolet curable adhesive is disclosed as a binder having a low dielectric constant, which comprises a reaction of a hydrogenated polybutadiene polyol, a polyisocyanate, and a hydroxyl group-containing (meth) acrylate. A urethane (meth) acrylate (for example, refer to Patent Document 2).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1]: Japanese Patent Laid-Open Publication No. 2011-162770

[Patent Document 2]: Japanese Patent Laid-Open Publication No. 2002-309185

However, the urethane (meth) acrylate obtained by reacting a polyester-based polyol of adipic acid, a polyisocyanate, and a hydroxyl group-containing (meth) acrylate disclosed in the above Patent Document 1 The electric constant is usually as high as 8.0, and the required performance cannot be satisfied in the case where the optical component is applied to suppress the malfunction of the touch panel.

Further, the urethane (meth) acrylate obtained by reacting a hydrogenated polybutadiene polyol, a polyisocyanate, and a hydroxyl group-containing (meth) acrylate described in Patent Document 2 has a low dielectric constant. To the extent of 3.0, however, due to the low polarity of the hydrogenated polybutadiene polyol, the resulting urethane (methyl) Since the acrylate itself has a low polarity and is incompatible with other monomers or resins, it has a problem that the degree of freedom in material selection is small and handling is difficult.

In view of the above, it is an object of the present invention to provide an active energy ray-curable composition containing a urethane (meth) acrylate having a low dielectric constant and excellent compatibility. Further, an active energy ray-curable adhesive composition containing the active energy ray-curable composition, a binder, a binder sheet, and a novel urethane (meth) acrylate are also provided.

However, the inventors of the present invention have found in an active energy ray-curable composition containing a urethane (meth) acrylate obtained by reacting a polyester-based polyol, as a result of repeated efforts in view of the above. The present invention can be obtained by obtaining a binder having a low dielectric constant and excellent compatibility by setting the dielectric constant of the urethane (meth) acrylate to a specific value or less.

That is, the gist of the present invention is as follows.

[1] An active energy ray-curable composition comprising a urethane of a reaction product of a polyester-based polyol (a1), a polyisocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3) The (meth) acrylate (A) and the urethane (meth) acrylate (A) have a dielectric constant of 7.0 or less.

[2] The active energy ray-curable composition according to the above [1], wherein the content X of the oxygen atom in the repeating structural unit of the polyester-based polyol (a1) is 0.35 or less. The content rate X is a value represented by the following formula (1).

X=16c/(12a+b+16c)...(1)

a: the number of carbon atoms in the repeating structural unit of the polyester-based polyol (a1)

b: the number of hydrogen atoms in the repeating structural unit of the polyester-based polyol (a1)

c: number of oxygen atoms in the repeating structural unit of the polyester-based polyol (a1)

[3] The active energy ray-curable composition according to [1], wherein the polyester-based polyol (a1) is a polyvalent carboxylic acid containing an alkylene group having 5 to 20 carbon atoms. A polycondensate of a polyvalent carboxylic acid component and a polyvalent alcohol component.

[4] The active energy ray-curable composition according to any one of [1] to [3] wherein the polyester-based polyol (a1) has a number average molecular weight of 500 to 12,000.

[5] The active energy ray-curable composition according to any one of [1], wherein the urethane (meth) acrylate (A) has a weight average molecular weight of 1,000 to 100,000. .

[6] The active energy ray-curable composition according to any one of [1] to [5] further comprising an ethylenically unsaturated monomer (B) (wherein the aforementioned urethane (methyl) ) except for acrylate (A).

[7] An active energy ray-curable adhesive composition, which comprises the active energy ray-curable composition according to any one of [1] to [6].

[8] A binder which is an adhesive obtained by curing the active energy ray-curable adhesive composition according to [7].

[9] A bonded sheet in which a binder as described in [8] is laminated on a substrate sheet.

[10] A urethane (meth) acrylate which is a polycondensate of a polyvalent carboxylic acid component and a polyvalent alcohol component of a polyvalent carboxylic acid having an alkylene group having 5 to 20 carbon atoms A reaction product of a polyester-based polyol (a1), a polyisocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3).

According to the active energy ray-curable composition of the present invention, a binder composition having a low dielectric constant and excellent compatibility can be obtained, and these cured binders are useful as binders for optical members, and are particularly suitable for use. Touch panel use, etc.

The invention is described in detail below.

Further, in the present invention, (meth)acrylic acid means acrylic acid and/or methacrylic acid, and (meth)acrylic acid (meth)acrylic acid (meth)acrylic acid (meth)acrylic acid and/or methacrylic acid group, (methyl) The meth acryloyl represents an acryl fluorenyl group and/or a methacryl fluorenyl group, and the (meth) acrylate means an acrylate and/or a methacrylate. Further, the acrylic resin is a resin obtained by polymerizing at least one (meth) acrylate monomer alone, or a resin obtained by polymerizing a polymerization component containing at least one (meth) acrylate monomer.

Further, in the present specification, the "~" of the numerical range is used, and the numerical values described before and after are included in the meaning including the lower limit and the upper limit.

The active energy ray-curable composition of the present invention is an amine group containing a reaction product obtained by reacting a polyester polyol (a1), a polyisocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3). An acid ray curable composition having a dielectric constant of 7.0 or less of the formate (meth) acrylate (A) and the urethane (meth) acrylate (A).

Here, the dielectric constant means a value of the degree of polarization of the substance to which the electric field is applied.

In the present invention, the dielectric constant of the urethane (meth) acrylate is for mixing 1-hydroxy-cyclohexyl-phenyl with respect to 100 parts by weight of the urethane (meth) acrylate. The cured film obtained by curing the active energy ray-curable composition of 4 parts by weight of the ketone and the solvent was measured, and specifically, the value of the dielectric constant was measured by the following method.

(test methods)

An active energy ray-curable composition containing 4 parts by weight of a photopolymerization initiator 1-hydroxy-cyclohexyl-phenyl-ketone and a solvent, based on 100 parts by weight of the urethane (meth) acrylate, The film thickness after curing was 150 μm, and it was applied to an untreated polyethylene terephthalate (PET) film (thickness: 50 μm) using an applicator, and left in a dryer at 60° C. for 10 minutes to make a solvent. Volatile. Thereafter, a polyethylene terephthalate (PET) film (thickness: 50 μm) was laminated from above to the surface of the active energy ray-curable composition, and a table UV irradiation device (manufactured by EYE GRAPHICS Co., Ltd., "Conveyor Belt" Conveyor-type tabletop irradiation device") Cured cured film by irradiating ultraviolet rays from the laminate side under conditions of 80 W/cm (high-pressure mercury lamp) × 18 cmH × 2.04 m/min × 3 Pass (accumulated irradiation amount: 2,400 mJ/cm ² ) The test piece was cut into 7 cm × 7 cm as a dielectric constant measurement.

In the test piece for measuring the dielectric constant, an HP4284A Precision LCR Meter (manufactured by Agilent) was used to sandwich the test piece between the electrodes, and an electric field was applied at a frequency of 1 MHz to measure the capacitance, and the capacitance between the electrodes was changed to calculate the activity. The dielectric constant of the energy ray-curable composition.

The urethane (meth) acrylate (A) used in the present invention is a reaction of a polyester polyol (a1), a polyisocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3). The resulting reaction product.

The polyester-based polyol (a1) of the present invention includes, for example, a condensation polymer (polycondensate) of a polyvalent alcohol component and a polyvalent carboxylic acid component, and ring-opening polymerization of a cyclic ester (lactone) component. A reactant derived from three kinds of components of a polyvalent alcohol component, a polyvalent carboxylic acid component, and a cyclic ester component.

Examples of the polyvalent alcohol component include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,4-tetramethylene glycol, and 1,3-tetramethylene. Glycol, 2-methyl-1,3-trimethylene glycol, 1,5-pentamethylene glycol, neopentyl glycol, 1,6-hexamethylene glycol, 3-methyl 1,5-pentamethylene glycol, 2,4-diethyl-1,5-pentamethylene glycol, 1,9-nonanediol, cyclohexanediol (1, a divalent alcohol such as 4-cyclohexanediol or the like; a bisphenol (such as bisphenol A); a trivalent alcohol such as glycerin, trimethylolpropane or trimethylolethane; and a sugar alcohol (wood) Sugar alcohol, sorbitol, etc. Among these, a divalent alcohol is preferred from the viewpoint of excellent generality, and particularly preferred are ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, and 1,4-tetramethylene. Glycol, 2-methyl-1,3-trimethylene glycol, neopentyl glycol.

These may be used alone or in combination of two or more.

Examples of the polyvalent carboxylic acid component include malonic acid, maleic acid, fumaric acid, succinic acid, glutaric acid, adipic acid, suberic acid, sebacic acid, sebacic acid, and twelve. An aliphatic dicarboxylic acid such as an alkanoic acid; an alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid; terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalene An aromatic dicarboxylic acid such as dicarboxylic acid, terephthalic acid or trimellitic acid. Some of these Among them, from the viewpoint of less yellowing, an aliphatic dicarboxylic acid is preferred, and succinic acid, adipic acid, and sebacic acid are particularly preferred.

These may be used alone or in combination of two or more.

Examples of the cyclic ester component include propiolactone, β-methyl-δ-valerolactone, and ε-caprolactone.

In the present invention, as the polyester-based polyol (a1), the content ratio X of oxygen atoms in the repeating structural unit of the polyester-based polyol (a1) is preferably 0.35 or less. The content rate X is a value represented by the following formula (1).

X=16c/(12a+b+16c)...(1)

a: the number of carbon atoms in the repeating structural unit of the polyester-based polyol (a1)

b: the number of hydrogen atoms in the repeating structural unit of the polyester-based polyol (a1)

c: number of oxygen atoms in the repeating structural unit of the polyester-based polyol (a1)

For example, in the case where the polyester-based polyol (a1) is a copolymer of ethylene glycol and adipic acid, the repeating structural unit is represented by the following structural formula. In the formula, n represents the number of repetitions of the repeating structural unit.

In this case, in the above formula (1), a content of the oxygen atom in the repeating structural unit represented by the above formula (1) is X=0.37, since a=8, b=1, and c=4.

Further, from the viewpoint of low dielectric properties, as the polyvalent carboxylic acid component constituting the polyester polyol (a1), it is preferred to contain an alkylene having a carbon number of 5 to 20. The polyvalent carboxylic acid of the group is more preferably a polyvalent carboxylic acid having a carbon number of 6 to 18, particularly preferably an alkylene group having 7 to 16 carbon atoms. The polyester-based polyol (a1) is more preferably a condensed polymer containing a polyvalent carboxylic acid component and a polyvalent alcohol component of a polyvalent carboxylic acid having an alkylene group having 5 to 20 carbon atoms.

When the number of carbon atoms of the alkylene group of the polyvalent carboxylic acid is too small, the dielectric constant tends to be high, and when the carbon number is too large, the crystallinity becomes high and handling tends to be difficult.

Specific examples of the polyvalent carboxylic acid having an alkylene group having 5 to 20 carbon atoms include pimelic acid, suberic acid, sebacic acid, sebacic acid, dodecanoic acid, eicosanoic acid, and isophthalic acid. Eicosanic acid.

In the case of using the polyvalent carboxylic acid having an alkylene group having 5 to 20 carbon atoms, from the viewpoint of low dielectric properties, it is preferably contained in an amount of 10 to 100 mol% based on the entire polyvalent carboxylic acid component. It is 20% to 100% by mole, especially contains 25 to 100%, and especially preferably contains 30 to 100%.

When the content ratio of the polyvalent carboxylic acid having an alkylene group having 5 to 20 carbon atoms is too small relative to the entire polyvalent carboxylic acid, the dielectric constant tends to be high.

Further, the number of hydroxyl groups contained in the polyester-based polyol (a1) is preferably 2 to 5, more preferably 2 to 3, still more preferably 2 per molecule. When the number of hydroxyl groups is too large, gelation tends to occur easily during the reaction.

The number average molecular weight of the polyester-based polyol (a1) is preferably 500 to 12,000, more preferably 600 to 10,000, and particularly preferably 700 to 8,000.

When the number average molecular weight is too large, the viscosity tends to be high and the workability tends to be lowered. When the number average molecular weight is too small, it tends to be difficult to obtain sufficient adhesion.

Further, the above number average molecular weight is a value obtained by the following.

Further, the number of functional groups (F) in the formula represents the number of hydroxyl groups contained in one molecule.

The valence of the hydroxyl group of the polyester-based polyol (a1) is preferably from 10 to 400 mgKOH/g, particularly preferably from 20 to 300 mgKOH/g, still more preferably from 30 to 250 mgKOH/g. When the valence of the hydroxy group is too high, the urethane (meth) acrylate tends to have a low molecular weight and the adhesiveness is lowered. When the valence is too low, the viscosity tends to be high and the workability tends to be lowered.

The above hydroxyl value can be measured based on JIS K 0070-1992.

Examples of the polyisocyanate (a2) include methylphenyl diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, and benzodimethyl diisocyanate. An aromatic polyisocyanate such as tetramethyl dimethyl diisocyanate, phenyl diisocyanate or naphthalene diisocyanate; pentamethylene diisocyanate, hexamethylene diisocyanate, trimethyl hexamethylene diisocyanate An aliphatic polyisocyanate such as lysine diisocyanate or lysine triisocyanate; hydrogenated diphenylmethane diisocyanate, hydrogenated dimethyl diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1 , an alicyclic polyisocyanate such as 3-bis(isocyanatemethyl)cyclohexane, or a ternary compound or a polyvalent compound of such polyisocyanate, an allophanate type polyisocyanate, a biuret type Polyisocyanate, water-dispersible polyisocyanate, and the like.

Among these, from the viewpoint of excellent stability of the reaction, a diisocyanate is preferred, and it is particularly preferred to use pentamethylene diisocyanate or hexamethylene diiso. An aliphatic polyisocyanate such as cyanate ester, trimethylhexamethylene diisocyanate or lysine diisocyanate; hydrogenated diphenylmethane diisocyanate, hydrogenated dimethyl diisocyanate, isophorone diisocyanate, An alicyclic polyisocyanate such as norbornene diisocyanate or 1,3-bis(isocyanatemethyl)cyclohexane, and more preferably a hydrogenated benzodimethyl group from the point of excellent reactivity and versatility. Isocyanate, isophorone diisocyanate.

Further, the above polyisocyanate may be used singly or in combination of two or more kinds.

Examples of the hydroxyl group-containing (meth) acrylate (a3) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxy (meth) acrylate. a (meth)acrylic acid hydroxyl group having an alkyl group such as butyl ester, 4-hydroxybutyl (meth)acrylate or 6-hydroxyhexyl (meth)acrylate having a carbon number of 2 to 20 (preferably 2 to 18) Alkyl ester, 2-hydroxyethyl propylene sulfhydryl sulfate, 2-(methyl) propylene methoxyethyl 2-hydroxypropyl phthalate, caprolactone modified (meth) acrylate 2-hydroxyethyl ester, dipropylene glycol (meth) acrylate, fatty acid modified-glycidyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate a (meth) acrylate containing one ethylenically unsaturated group such as 2-hydroxy-3-(meth)acryloxypropyl (meth) acrylate; glycerol di(meth) acrylate, (meth)acrylate containing two ethylenically unsaturated groups, such as 2-hydroxy-3-propenyl-methoxypropyl methacrylate; pentaerythritol tri(meth)acrylate, caprolactone modification Pentaerythritol tri(meth)acrylate Ethylene oxide modified pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol penta (meth) acrylate, ethylene oxide modified dipentaerythritol five ( Methyl) acrylate or the like contains 3 or more B An ethylenically unsaturated group (meth) acrylate. The hydroxy group-containing (meth) acrylate (a3) may be used singly or in combination of two or more kinds.

Among these, from the viewpoint of excellent flexibility of the adhesive layer, a hydroxyl group-containing (meth) acrylate containing one ethylenically unsaturated group is preferred, and 2-hydroxyethyl (meth) acrylate is more preferred. (methyl) 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, etc. The hydroxyalkyl acrylate is preferably 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate from the viewpoint of excellent reactivity and general versatility.

In the present invention, the urethane (meth) acrylate (A) can be produced as follows.

For example, (1) a method in which a polyester-based polyol (a1), a polyisocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3) are added to a reactor or separately, and reacted ( 2) A method of reacting a hydroxyl group-containing (meth) acrylate (a3) in a reaction product obtained by previously reacting a polyester-based polyol (a1) and a polyisocyanate (a2).

Further, the urethane (meth) acrylate (A) is preferably a polycondensation of a polyvalent carboxylic acid component and a polyvalent alcohol component of a polyvalent carboxylic acid having an alkylene group having 5 to 20 carbon atoms. a reaction product of a polyester-based polyol (a1), a polyisocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3), which is a urethane (meth) acrylate of the reaction product Esters are novel compounds regardless of their dielectric constant.

For the production of the urethane (meth) acrylate (A), the polyester polyol (a1) and the polyisocyanate (a2) are pre-reacted. In the obtained reaction product, a method of reacting a hydroxyl group-containing (meth) acrylate (a3) will be described.

A known reaction means can be used for the reaction of the polyester-based polyol (a1) with the polyisocyanate (a2). In this case, for example, the molar ratio of the hydroxyl group in the isocyanate group of the polyisocyanate (a2) to the polyester polyol (a1) is usually 2n: (2n-2) (n is an integer of 2 or more) To the extent that the terminal isocyanate group-containing urethane (meth) acrylate remaining in the isocyanate group can be obtained, and the compound can be added to the hydroxyl group-containing (meth) acrylate (a3). Into a reaction.

The reaction product obtained by previously reacting the polyester polyol (a1) with the polyisocyanate (a2) and the addition reaction with the hydroxyl group-containing (meth) acrylate (a3) can be carried out by using a known reaction means. .

The molar ratio of the reaction product to the hydroxyl group-containing (meth) acrylate (a3) is, for example, two of the isocyanate groups of the reaction product, and the hydroxyl group of the (meth) acrylate (a3) having a hydroxyl group. In the case of one, the reaction product: the hydroxyl group-containing (meth) acrylate (a3) is 1:2, the reaction product has three isocyanate groups, and the hydroxyl group-containing (meth) acrylate ( When the hydroxyl group of a3) is one, the reaction product: the hydroxyl group-containing (meth)acrylate (a3) is about 1:3.

In the addition reaction of the reaction product with the hydroxyl group-containing (meth) acrylate (a3), the reaction is completed by setting the residual isocyanate group content of the reaction system to 0.3% by weight or less to obtain an amine group. Formate (meth) acrylate (A).

Such a polyester-based polyol (a1) and a polyisocyanate (a2) In the reaction and further reaction of the reaction product with the hydroxyl group-containing (meth) acrylate (a3), it is preferred to use a catalyst for the purpose of promoting the reaction. Examples of such a catalyst include dibutyltin dilaurate, dibutyltin diacetate, trimethyltin peroxide, tetra-n-butyltin, zinc acetoacetate, and zirconium triacetate. An organometallic compound such as ethyl acetoacetate or zirconium tetraacetate, zinc octenoate, zinc hexanoate, zinc octate, zinc stearate, zirconium 2-ethylhexanoate, naphthenic acid a metal salt of cobalt, stannous chloride, tin chloride, potassium acetate, etc., triethylamine, triethylenediamine, benzyldiethylamine, 1,4-diazabicyclo[2,2,2 Octane, 1,8-diazabicyclo[5,4,0]undecane, N,N,N',N'-tetramethyl-1,3-butanediamine, N-methyl An amine-based catalyst such as morpholine or N-ethylmorpholine, cerium nitrate, cerium bromide, cerium iodide, cerium sulfide, etc., dibutyl cerium dilaurate, dioctyl hydrazine dilaurate, etc. Organic bismuth compound, or bismuth 2-ethylhexanoate, bismuth naphthenate, bismuth isodecanoate, bismuth neodecanoate, bismuth laurate, strontium maleate, strontium stearate , oleic acid strontium salt, linoleic acid strontium salt, strontium acetate bismuth, bismuth bismuth citrate, bismuth subsalicylate, two galls Organic acid salts of bismuth such as bismuth salts such as bismuth-based catalyst and the like, which is preferably dibutyl tin dilaurate, 1,8-diazabicyclo [5.4.0] undecane. These may be used alone or in combination of two or more.

Further, in the reaction of the polyester-based polyol (a1) with the polyisocyanate (a2) and further the reaction product with the hydroxyl group-containing (meth) acrylate (a3), it is also possible to use a non-isocyanate if necessary. Examples of the organic solvent of the functional group for the radical reaction include esters such as ethyl acetate and butyl acetate, ketones such as methyl ethyl ketone and methyl isobutyl ketone, and aromatics such as toluene and xylene. An organic solvent such as a group or an ethylenically unsaturated monomer (for example, an ethylenically unsaturated monomer (B) as described later).

Further, the reaction temperature is usually from 30 to 90 ° C, preferably from 40 to 80 ° C, and the reaction time is usually from 2 to 10 hours, preferably from 3 to 8 hours.

The urethane (meth) acrylate (A) thus obtained has a dielectric constant of 7.0 or less, and is preferably 6.5 or less, and more preferably 6.0 or less from the viewpoint of suppressing malfunction of the touch panel. Also, the lower limit of the dielectric constant is usually 1.0.

When the dielectric constant is too high, the electrostatic capacitance between the electrodes mounted on the touch panel tends to increase, which may cause a malfunction. When the dielectric constant is too low, the electrostatic capacitance decreases, and the detection sensitivity tends to decrease.

The urethane (meth) acrylate (A) of the present invention preferably has a weight average molecular weight of 1,000 to 100,000, particularly preferably 5,000 to 90,000, more preferably 10,000 to 80,000. When the weight average molecular weight is too small, the adhesive strength tends to decrease, and if it is too large, the viscosity tends to be too high and coating tends to be difficult.

Further, the weight average molecular weight is a weight average molecular weight obtained by converting the molecular weight of the standard polystyrene, and is used in a high-speed liquid chromatography ("Shodex GPC system-11 type" manufactured by Showa Denko Co., Ltd.), using a column: Shodex GPC KF -806L (excluding the limit molecular weight: 2 × 10 ⁷ , separation range: 100 ~ 2 × 10 ⁷ , theoretical plate number 10,000 plates / support, filler material: styrene - divinyl benzene copolymer, filler particle size: 10 μm The values measured in series of 3 branches.

Further, regarding the viscosity of the urethane (meth) acrylate (A) of the present invention, the viscosity at 60 ° C is preferably 1,000 to 1,000,000 mPa. s, especially good is 2,000~900,000mPa. s, more preferably 3,000~800,000mPa. s. When the viscosity is too high, handling tends to be difficult. When the viscosity is too low, film thickness control during coating tends to be difficult.

Also, the viscosity is measured by an E-type viscometer.

The active energy ray-curable composition of the present invention preferably further contains an ethylenically unsaturated monomer (B) in addition to the aforementioned urethane (meth) acrylate (A) (wherein the urethane) (except for (meth) acrylate (A)).

The ethylenically unsaturated monomer (B) used in the present invention may, for example, be a monofunctional monomer, a bifunctional monomer or a trifunctional or higher monomer.

Examples of the monofunctional monomer include styrene monomers such as styrene, vinyltoluene, chlorostyrene, and α-methylstyrene, and methyl (meth)acrylate and (meth)acrylic acid. Ethyl ester, acrylonitrile, 2-methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate Ester, 4-hydroxybutyl (meth)acrylate, phenoxyethyl (meth)acrylate, 2-phenoxy-2-hydroxypropyl (meth)acrylate, 2-hydroxy-(meth)acrylate- 3-phenoxypropyl ester, 3-chloro-2-hydroxypropyl (meth)acrylate, glycerol mono(meth)acrylate, glycidyl (meth)acrylate, lauric acid (meth)acrylate, Cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, tricyclodecyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl (meth)acrylate Ethyl ester, dicyclopentanyl (meth)acrylate, (2-methyl-2-ethyl-1,3-dioxolan-4-yl)-methyl (meth)acrylate, (A) Base) Cyclohexanespirol-2-(1,3-dioxol-4-yl)-methyl acrylate, (methyl) propyl 3-ethyl-3-oxetanylcarboxylate, γ-caprolactone (meth)acrylate, n-butyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate , octyl (meth) acrylate, decyl (meth) acrylate, (methyl) Ethyl acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, n-stearate (meth)acrylate, benzyl (meth)acrylate, phenol oxirane ( n=2) (meth) acrylate, nonylphenol propylene oxide modified (n=2.5) (meth) acrylate, 2-(meth) propylene oxiranyl ethyl acid phosphate, 2-( Semi-(meth) acrylate of phthalic acid derivatives such as methyl propylene oxy-2-hydroxypropyl phthalate, furyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate , carbitol (meth)acrylate, benzyl (meth)acrylate, butoxyethyl (meth)acrylate, allyl (meth)acrylate, (meth)acryloylmorpholine, polyoxygen a (meth) acrylate monomer such as a vinylidene alkyl ether acrylate, 2-hydroxyethyl acrylamide, N-methylol methacrylate, N-vinyl pyrrolidone, 2-vinylpyridine, vinyl acetate, and the like.

Examples of the bifunctional monomer include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and polyethylene. Alcohol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, butanediol di(meth)acrylate, new Pentanediol di(meth)acrylate, ethylene oxide modified bisphenol A di(meth)acrylate, propylene oxide modified bisphenol A di(meth)acrylate, cyclohexane Methanol di(meth)acrylate, ethoxycyclohexanedimethanol di(meth)acrylate, dimethylol dicyclopentane di(meth)acrylate, tricyclodecane dimethanol di(methyl) Acrylate, 1,6-hexanediol di(meth)acrylate, di(meth)acrylate, pentaerythritol di(meth)acrylate, ethylene glycol diglycidyl ether di(methyl) Acrylate, diethylene glycol diglycidyl ether di(methyl) Acrylate, diglycidyl phthalate di(meth) acrylate, hydroxytrimethylacetic acid modified neopentyl glycol di(meth) acrylate, isocyanuric acid oxirane modified diacrylate Wait.

Examples of the trifunctional monomer include trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol penta(methyl). Acrylate, dipentaerythritol hexa(meth) acrylate, tris(meth) propylene oxiranoxy trimethylolpropane, glycerol polyglycidyl ether poly(meth) acrylate, isocyanuric acid epoxy B Alkyl modified triacrylate, caprolactone modified dipentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate, caprolactone modified pentaerythritol tri (meth) acrylate , caprolactone modified pentaerythritol tetra (meth) acrylate, ethylene oxide modified dipentaerythritol penta (meth) acrylate, ethylene oxide modified dipentaerythritol hexa (meth) acrylate, epoxy B The alkene is modified with pentaerythritol tri(meth)acrylate, ethylene oxide modified pentaerythritol tetra(meth)acrylate, epoxidized glycerin triacrylate, and the like.

Further, a Michael adduct of acrylic acid or a 2-propenyloxyethyl dicarboxylic acid monoester may be used in combination, and the Mickel addition of the acrylic acid may, for example, be an acrylic acid binary or methacrylic acid. Binary body, acrylic ternary body, methacrylic acid ternary body, acrylic acid quaternary body, methacrylic acid quaternary body, and the like.

The 2-propylene oxirane ethyl dicarboxylic acid monoester is a carboxylic acid having a specific substituent, and examples thereof include 2-propenyl oxyethyl succinic acid monoester and 2-methyl propylene oxy oxyethyl ester. Succinic acid monoester, 2-propenyl oxiranyl phthalate monoester, 2-methylpropenyl oxyethyl phthalate monoester, 2-propenyl oxiranyl hexahydrophthalic acid monoester , 2-methylpropenyl oxiranyl hexahydrophthalic acid monoester, and the like. Yet Further, other oligoester acrylates can also be mentioned.

The content of the ethylenically unsaturated monomer (B) is preferably from 5 to 900 parts by weight, particularly preferably from 10 to 600 parts by weight, per 100 parts by weight of the urethane (meth) acrylate (A). More preferably, it is 15 to 400 parts by weight. When the content is too large, the viscosity tends to be low, and the adhesive strength tends to be lowered. When the content is too small, the viscosity tends to be high and the coatability tends to be lowered.

In the present invention, it is preferred that the active energy ray-curable composition further contains a photopolymerization initiator (C), and as the photopolymerization initiator (C), as long as a radical can be generated by light action, Specially limited. For example, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, benzyl dimethyl acetal, 4-(2-hydroxyethoxy) Phenyl-(2-hydroxy-2-propyl)one, 1-hydroxycyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl -1-propan-1-one, 2-methyl-2-morpholinyl (4-thiomethylphenyl)propan-1-one, 2-benzyl-2-dimethylamino-1- Acetophenones such as 4-morpholinylphenyl)butanone and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]acetone oligomer; benzoin, Benzoin such as benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether; benzophenone, methyl phthalate; 4-phenylbenzophenone, 4-benzylidene-4'-methyl-diphenyl sulfide, 3,3',4,4'-tetrakis(t-butylperoxycarbonyl)diphenyl Methyl ketone, 2,4,6-trimethylbenzophenone, 4-benzylidene-N,N-dimethyl-N-[2-(1-keto(oxo)-2-propenyloxy) Benzophenones such as ethyl] benzammonium bromide and (4-benzylidenebenzyl)trimethylammonium chloride; 2-isopropylthioxanthone, 4-isopropylthiophene Tons of ketone, 2,4-diethylthioxanthone 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thio Thiophenone, 9-ketomethyl chloride, etc. Tons of ketones; 2,4,6-trimethylbenzylidene-diphenylphosphine oxide, bis(2,6-dimethoxybenzylidene)-2,4,4-trimethyl- a mercaptophosphine oxide such as pentylphosphine oxide or bis(2,4,6-trimethylbenzylidene)-phenylphosphine oxide; In addition, these photopolymerization initiators may be used alone or in combination of two or more.

Further, as an auxiliary agent of such a photopolymerization initiator (C), triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (michlerone), 4 may be used in combination. , 4'-diethylaminobenzophenone, 2-dimethylaminoethyl benzoate, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoic acid (n-butyl) Oxy)ethyl ester, isoamyl 4-dimethylaminobenzoate, 2-ethylhexyl 4-dimethylaminobenzoate, 2,4-diethylthioxanthone, 2,4- Diisopropyl thioxanthone and the like. These additives may be used alone or in combination of two or more.

The content of the photopolymerization initiator (C) is urethane with respect to the urethane (meth) acrylate (A) (in the case where the ethylenically unsaturated monomer (B) is further contained) The total of the ester (meth) acrylate (A) and the ethylenically unsaturated monomer (B) is 100 parts by weight, preferably 1 to 10 parts by weight, particularly preferably 2 to 5 parts by weight. When the content is too small, the curing speed tends to decrease. When the content is too large, the curability does not increase and the economical property tends to decrease.

In addition to the urethane (meth) acrylate (A), the ethylenically unsaturated monomer (B), and the photopolymerization initiator (C), the active energy ray-curable composition of the present invention is also It can be combined with antioxidants, flame retardants, antistatic agents, fillers, levelers, stabilizers, reinforcing agents, bleaching agents, etc. Further, as the crosslinking agent, a compound having a crosslinking action due to heat can be used, and specifically, an epoxy compound, an aziridine compound, a melamine compound, an isocyanate compound, or a chelate compound can be used. Moreover, as a hydrolysis inhibitor, A carbodiimide can also be used.

Further, in the active energy ray-curable composition of the present invention, if necessary, in order to adjust the viscosity at the time of coating, an alcohol such as methanol, ethanol, propanol, n-butanol or isobutanol for dilution may be used; Ketones such as acetone, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone; celecoxibs such as ethyl serotonin; aromatics such as toluene and xylene; propylene glycol monomethyl ether An alcohol ether; an acetate such as methyl acetate, ethyl acetate or butyl acetate; or a diluent solvent such as a diketone; however, it is preferably based on the residual solvent in the coating film or the possibility of volatilization of the solidified component during drying. It is essentially free of solvents.

In addition, the content of the active energy ray-curable composition is usually 1% by weight or less, preferably 0.5% by weight or less, and more preferably 0.1% by weight or less based on the total amount of the active energy ray-curable composition.

The active energy ray-curable composition of the present invention can be used as a coating composition for various substrate films, and can be used as a binder composition for bonding or surface-protecting sheets of various members, but as an active energy. Radiation-curable adhesive compositions are particularly useful.

Furthermore, the active energy ray-curable pressure-sensitive adhesive composition of the present invention may contain an adhesion-imparting agent such as a polythiol from the viewpoint of suppressing the unreacted component and improving the adhesion.

The polythiol compound is preferably a compound having 2 to 6 thiol groups in the molecule, and examples thereof include aliphatic polythiols such as an alkanedithiol having a carbon number of 2 to 20; and benzylidene; An aromatic polythiol such as a dithiol, a polythiol substituted with a thiol group in a halogen atom of an alcoholic halo alcohol addition product, or a hydrogen sulfide reaction product of a polyepoxide compound. Polythiol; 2 to 6 in the molecule a polythiol composed of a polyvalent alcohol of a hydroxyl group and an esterified product of thioglycolic acid, β-thiol propionic acid or β-thiol butyric acid, and the like may be used alone or in combination of two. the above.

The content of the above-mentioned polythiol compound is a urethane relative to the urethane (meth) acrylate (A) (in the case of further containing the ethylenically unsaturated monomer (B)) The total amount of the methyl acrylate (A) and the ethylenically unsaturated monomer (B) is 100 parts by weight, preferably 10 parts by weight or less, and particularly preferably 0.01 to 5 parts by weight.

The active energy ray-curable adhesive composition of the present invention is preferably a cured adhesive. Specifically, it is usually applied to a substrate sheet or the like as a binder sheet or the like for practical use, and after being applied to a substrate sheet or the like, it is a crosslinked binder by irradiation with an active energy ray. And found adhesion.

Further, in the case where it is not particularly specified, the adhesive sheet is intended to include an adhesive film or an adhesive tape, and is characterized in that a binder obtained by curing the active energy ray-curable pressure-sensitive adhesive composition of the present invention is laminated.

Further, in the present invention, the bonded sheet can be bonded to the adherend (component), and the separator can be separated from the surface layer of the adhesive for the purpose of protecting the adhesive from contamination.

The base material sheet may, for example, be a polyester resin such as polyethylene terephthalate or polybutylene terephthalate; or a polyethylene, a polypropylene or an ethylene-propylene copolymer. Olefin resin; polycarbonate, urethane resin, acrylic resin, polystyrene resin, ethylene-vinyl acetate copolymer, polyvinyl chloride, polybutene, polyester, polymethylpentene, acrylonitrile A resin sheet such as a butadiene styrene copolymer (ABS) or a glass plate. Can also It is used for surface treatment of various substrate sheets through anchoring layer, corona treatment, plasma treatment and the like.

As the above-mentioned separation sheet, a resin sheet as exemplified above as a base material sheet, or a substrate such as paper, cloth, or nonwoven fabric can be used as a release film.

When a binder layer is formed on a base material sheet, a direct coating method in which an active energy ray-curable pressure-sensitive adhesive composition is directly applied to a substrate sheet, or an active energy ray-curable adhesive may be mentioned. The composition is applied to a transfer coating method or the like which is applied to a substrate sheet after being separated into a sheet.

The active energy ray-curable adhesive composition is usually applied after being adjusted to a viscosity suitable for coating with a solvent. The method of applying the active energy ray-curable pressure-sensitive adhesive composition to the substrate sheet or the separation sheet is not particularly limited, and examples thereof include spray coating, shower coating, dip coating, roll coating, spin coating, and curtain. Wet coating methods such as coating, flow coating, slit coating, die coating, gravure printing, dot printing, screen printing, inkjet printing, printing by a dispenser, and the like.

When the coated active energy ray-curable composition contains a solvent, it is dried after application, and as a drying condition, it is sufficient to sufficiently evaporate the solvent in the applied active energy ray-curable composition. Drying temperature and drying time can be used. The drying temperature is usually 40 to 100 ° C, and particularly preferably 50 to 90 ° C. As the drying time, it is preferably 1 to 60 minutes in consideration of production suitability.

Further, in the case where the active energy ray-curable adhesive composition is a solid or a high-viscosity liquid, the active energy ray-curable composition may be heated without adjusting the viscosity by a solvent, and the viscosity may be lowered to be coated by the above method. Hot melt method of cloth.

The active energy ray-curable pressure-sensitive adhesive composition of the present invention is applied to a substrate sheet and dried, and then becomes an adhesive sheet by irradiation with an active energy ray to form a crosslinked binder.

In the direct coating method, the active energy ray-curable adhesive composition may be applied to a substrate sheet, heated and dried, and then irradiated with an active energy ray, and then the separated sheet may be bonded thereto. After applying the active energy ray-curable adhesive composition to the base material sheet and heating and drying, the separated sheet is bonded, and then the active energy ray is irradiated. On the other hand, in the transfer coating method, the active energy ray-curable pressure-sensitive adhesive composition may be applied to the separation sheet, heated and dried, and then irradiated with an active energy ray, and then bonded to the substrate sheet, or The separation sheet is coated with an active energy ray-curable pressure-sensitive adhesive composition, heated and dried, and then bonded to a substrate sheet, and then irradiated with an active energy ray.

As the active energy ray, electromagnetic waves such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, and infrared rays, and electromagnetic waves such as X-rays and gamma rays can be used, and electron beams, proton wires, neutral beams, or the like can be used, and the curing speed and the irradiation device can be obtained. In terms of easiness, price, etc., it is preferred to cure by ultraviolet irradiation. Further, when electron beam irradiation is performed, it can be cured without using a photopolymerization initiator (C).

The method of curing by ultraviolet irradiation can use a high-pressure mercury lamp, an ultra-high pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a chemical lamp, an electrodeless discharge lamp, an LED lamp, etc., which emits light in the wavelength range of 150 to 450 nm, to 30~ Irradiation at a strength of about 5,000 mJ/cm ² .

After ultraviolet irradiation, it can also be heated as needed to achieve curing. complete.

Further, the thickness of the above-mentioned binder layer formed on the substrate sheet after irradiation with the active energy ray can be appropriately set depending on the application, and is usually 5 to 300 μm, preferably 10 to 250 μm. When the thickness of the adhesive layer is too small, the adhesive property tends to be difficult to be stabilized, and if it is too thick, the adhesive tends to be likely to remain.

The adhesive of the present invention thus obtained has a dielectric constant of 7.0 or less, and is preferably 6.5 or less, and more preferably 6.0 or less, from the viewpoint of suppressing malfunction of the touch panel. Also, the lower limit of the dielectric constant is usually 1.0.

When the dielectric constant is too high, the electrostatic capacitance between the electrodes mounted on the touch panel tends to increase, which tends to cause malfunction. When the dielectric constant is too low, the electrostatic capacitance decreases, and the detection sensitivity tends to decrease.

Further, the adhesive force of the adhesive sheet of the present invention is usually 0.1 to 100 N/25 mm, preferably 0.5 to 75 N/25 mm, more preferably 1 to 50 N/25 mm, and even more preferably 10 to 50 N/25 mm. Good for 17.5~50N/25mm.

Since the urethane (meth) acrylate of the present invention has a low dielectric constant, the active energy ray-curable composition of the present invention containing the same has a low dielectric constant, and the active energy ray-curable composition is contained. The active energy ray-curable adhesive composition or the cured adhesive thereof is useful as an adhesive for optical members such as an optical device such as a touch panel or an optical recording medium, and particularly, a touch panel is suitably used. The bonding use of the structural member or the organic electroluminescence display sealing use or the like.

Example

The present invention will be more specifically described below by way of examples, as long as it is not When it exceeds the gist of the present invention, it is not limited to the following examples. In addition, in the examples, "parts" and "%" are based on weight.

<Example 1>

[Synthesis of urethane acrylate (A-1)]

In a four-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet, 12.6 g (0.057 mol) of isophorone diisocyanate and a bifunctional polyester polyol (hydroxyl value: 60.3 mgKOH/g, number average) were added. The molecular weight is 2,000, the content of oxygen atoms in the repeating structural unit is X = 0.26, the polyvalent carboxylic acid component: 100% by mole of sebacic acid is contained, 84.7 g (0.046 mol), and dibutyltin laurate as a reaction catalyst. 0.02 g, after reacting at 80 ° C for 6 hours, 2.7 g (0.023 mol) of 2-hydroxyethyl acrylate and 0.04 g of 2,6-di-t-butyl cresol as a polymerization inhibiting agent were added, and reacted at 60 ° C for 3 hours. The reaction was terminated at a time point when the residual isocyanate group became 0.3% to obtain a urethane acrylate (A-1) (weight average molecular weight (Mw); 30,000).

The obtained urethane acrylate (A-1) was evaluated as follows.

<Dielectric constant>

With respect to 100 parts by weight of the urethane acrylate (A-1), 43 parts by weight of ethyl acetate was uniformly mixed with 1-hydroxy-cyclohexyl-phenyl-one as a photopolymerization initiator (BASF JAPAN Co., Ltd.) "IRGACURE 184") 4 parts were uniformly mixed to obtain an active energy ray-curable composition.

(Production of test piece for measuring dielectric constant)

The active energy ray-curable composition obtained above was applied to an untreated polyethylene terephthalate (PET) film (thickness: 50 μm) by an applicator so as to have a film thickness of 150 μm after curing. It was allowed to stand in a dryer at 60 ° C for 10 minutes to evaporate the solvent. Thereafter, an untreated polyethylene terephthalate (PET) film (thickness: 50 μm) was laminated on the active energy ray-curable composition side from above, and a table type UV irradiation apparatus (manufactured by EYE GRAPHICS Co., Ltd., "Conveyor Belt The table top irradiation device" is irradiated with ultraviolet rays from the laminate side under conditions of 80 W/cm (high pressure mercury lamp) × 18 cmH × 2.04 m/min × 3 Pass (accumulated irradiation amount: 2,400 mJ/cm ² ), and the cured cured film is cut into 7 cm × 7 cm to obtain a test piece for measuring the dielectric constant.

(test methods)

The obtained test piece was sandwiched between the electrodes by an HP4284A Precision LCR Meter (manufactured by Agilent), and an electric field was applied at a frequency of 1 MHz to measure the capacitance, and the capacitance of the active energy ray-curable composition was calculated from the change in capacitance between the electrodes. The electric constant was evaluated as follows. Further, the dielectric constant of the active energy ray-curable pressure-sensitive adhesive composition can be regarded as the dielectric constant of the urethane (meth) acrylate contained in the active energy ray-curable pressure-sensitive adhesive composition.

(evaluation benchmark)

○; below 7.0

×; greater than 7.0

<Compatibility>

The urethane acrylate (A-1) and the following ethylenically unsaturated monomer were individually blended in a weight ratio of 1:1, and after thorough mixing, the appearance of the compounding liquid was observed as follows. Evaluation.

(B-1) Aliphatic monomer: butyl acrylate

(B-2) Aromatic monomer: phenoxyethyl acrylate

(B-3) Hydroxyl-containing monomer: 4-hydroxybutyl acrylate

(evaluation benchmark)

○; the compounding liquid is uniform.

×; The compounding liquid is uneven.

Next, the adhesiveness of the active energy ray-curable adhesive composition containing the urethane acrylate (A-1) was evaluated.

<Adhesion>

81 parts of phenoxyethyl acrylate as the ethylenically unsaturated monomer (B) as a photopolymerization initiator 1-hydroxy-ring relative to 100 parts of the urethane acrylate (A-1) 7.2 parts of hexyl-phenyl-ketone ("IRGACURE 184" manufactured by BASF JAPAN Co., Ltd.) was uniformly mixed to obtain an active energy ray-curable adhesive composition.

(Production of adhesive sheet for measuring adhesion)

The obtained active energy ray-curable pressure-sensitive adhesive composition was applied to an easily adhered polyethylene terephthalate (PET) film (thickness: 125 μm) by an applicator so that the film thickness after curing was 175 μm. , a desktop type UV irradiation device ("Easy belt type table irradiation device" manufactured by EYE GRAPHICS Co., Ltd.) is 80 W/cm (high pressure mercury lamp) × 18 cmH × 2.04 m / min × 3 Pass (accumulated irradiation amount 2,400 mJ/cm ² ) Under the conditions, ultraviolet rays were irradiated and cured, whereby an adhesive sheet for measuring adhesion was obtained.

<experiment method>

After the obtained adhesive sheet was cut into 25 mm × 100 mm, the glass sheet as the adherend was pressed twice by a 2 kg rubber roller at 23 ° C and a relative humidity of 50% to prepare a test sheet. . The test sheet is in the same ring After leaving for 30 minutes, the 180-degree peeling test was performed by a peeling speed of 0.3 m/min, and the adhesive force (N/25 mm) was measured and evaluated by the following criteria.

(evaluation benchmark)

○; 17.5N/25mm or more

△; 10N/25mm or more, and less than 17.5N/25mm

×; less than 10N/25mm

<Example 2>

[Synthesis of urethane acrylate (A-2)]

In a 4-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet, 11.9 g (0.054 mol) of a isophorone diisocyanate and a bifunctional polyester polyol (hydroxyl value 56.0 mgKOH/g, number average) were added. The molecular weight is 2,000, the content of oxygen atoms in the repeating structural unit is X = 0.34, the polyvalent carboxylic acid component: 35 mol% of sebacic acid is contained, 85.6 g (0.043 mol), and dibutyltin laurate as a reaction catalyst 0.02 g, after reacting at 80 ° C for 6 hours, 2.5 g (0.022 mol) of 2-hydroxyethyl acrylate and 0.04 g of 2,6-di-t-butyl cresol as a polymerization inhibiting agent were added, and reacted at 60 ° C for 3 hours. The reaction was terminated at a time point when the residual isocyanate group became 0.3% to obtain a urethane acrylate (A-2) (weight average molecular weight (Mw); 38,000).

The dielectric properties and compatibility of the obtained urethane acrylate (A-2) were evaluated in the same manner as in Example 1. Further, the active energy ray-curable pressure-sensitive adhesive composition containing the urethane acrylate (A-2) was evaluated for the same adhesion as in Example 1.

<Comparative Example 1>

[Synthesis of urethane acrylate (A'-1)]

11.8 g (0.053 mol) of isophorone diisocyanate and a bifunctional polyester polyol (hydroxyl value 55.4 mgKOH/g, number average) were placed in a 4-neck flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet. The molecular weight is 2,000, the content of oxygen atoms in the repeating structural unit is X = 0.37, the polyvalent carboxylic acid component: 100 mol% of adipic acid is contained, 85.7 g (0.042 mol), and dibutyltin laurate as a reaction catalyst. 0.02 g, after reacting at 80 ° C for 6 hours, 2.5 g (0.022 mol) of 2-hydroxyethyl acrylate and 0.04 g of 2,6-di-t-butyl cresol as a polymerization inhibiting agent were added, and reacted at 60 ° C for 3 hours. The reaction was terminated at a time point when the residual isocyanate group became 0.3% to obtain a urethane acrylate (A'-1) (weight average molecular weight (Mw); 26,000).

The dielectric properties and compatibility of the obtained urethane acrylate (A'-1) were evaluated in the same manner as in Example 1. Further, the active energy ray-curable pressure-sensitive adhesive composition containing the urethane acrylate (A'-1) was evaluated for the same adhesion as in Example 1.

<Comparative Example 2> [Synthesis of urethane acrylate (A'-2)]

In a 4-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen gas inlet, 10.1 g (0.045 mol) of isophorone diisocyanate and a bifunctional hydrogenated polybutadiene polyol (hydroxyl value of 48.3 mgKOH/g) were added. , a number average molecular weight of 2,000) 87.7 g (0.038 mol), 0.02 g of dibutyltin laurate as a reaction catalyst, after reacting at 80 ° C for 6 hours, adding 2.2 g (0.015 mol) of 4-hydroxybutyl acrylate, 0.04 g of 2,6-di-t-butyl cresol as a polymerization inhibiting agent was reacted at 60 ° C for 3 hours, and the reaction was terminated when the residual isocyanate group became 0.3% to obtain a urethane acrylate (A'-2). (weight average molecular weight) (Mw); 49,000).

The dielectric properties and compatibility of the obtained urethane acrylate (A'-2) were evaluated in the same manner as in Example 1.

Next, 69 parts by weight of isodecyl acrylate as the ethylenically unsaturated monomer (B), as a photopolymerization initiator, was added to 100 parts by weight of the urethane acrylate (A'-2). 6.8 parts of hydroxy-cyclohexyl-phenyl-ketone ("IRGACURE 184" manufactured by BASF JAPAN Co., Ltd.) was uniformly mixed to obtain an active energy ray-curable pressure-sensitive adhesive composition, and the adhesion was evaluated in the same manner as in Example 1.

The above evaluation results are shown in Table 1 below.

According to the above evaluation, the urethane acrylates of Examples 1 and 2 having a dielectric constant of 7.0 or less have a good appearance and a good compatibility with a mixture of various ethylenically unsaturated monomers. Further, it was found that the active energy ray-curable adhesive compositions of Examples 1 and 2 containing the urethane acrylate exhibited excellent adhesion.

On the other hand, the urethane (meth) acrylate of Comparative Example 1 having a dielectric constant of more than 7.0 is excellent in compatibility, but has a high dielectric constant and is difficult to apply to an adhesive for optical members.

Further, the urethane acrylate of Comparative Example 2 in which the polybutadiene-based polyol is substituted for the polyester-based polyol has a dielectric constant of 7.0 or less, but the urethane acrylate is carried out. The case is poor in compatibility.

While the present invention has been described with respect to the embodiments of the present invention, the invention may be modified or modified without departing from the spirit and scope of the invention. The present application is based on Japanese Patent Application No. 2014-233837, filed on Nov.

[Industrial availability]

The active energy ray-curable composition of the present invention has a low dielectric constant, and the active energy ray-curable adhesive composition and the binder of the present invention containing the same are used as an optical device or an optical record such as a touch panel. An optical member such as a medium is useful as a binder, and in particular, it is suitable for use in a bonding use of a touch panel structural member or an organic electroluminescence display sealing application.

Claims (10)

An active energy ray-curable composition containing a polyester-based polyol (a1), a polyisocyanate (a2), and a urethane of a reaction product of a hydroxyl group-containing (meth) acrylate (a3) (methyl group) The acrylate (A) and the urethane (meth) acrylate (A) have a dielectric constant of 7.0 or less. The active energy ray-curable composition according to the first aspect of the invention, wherein the content X of the oxygen atom in the repeating structural unit of the polyester-based polyol (a1) is 0.35 or less, and the content ratio X is The value represented by the following formula (1): X = 16c / (12a + b + 16c) (1) a: the number of carbon atoms in the repeating structural unit of the polyester-based polyol (a1); b : the number of hydrogen atoms in the repeating structural unit of the polyester-based polyol (a1); c: the number of oxygen atoms in the repeating structural unit of the polyester-based polyol (a1). The active energy ray-curable composition according to claim 1 or 2, wherein the polyester-based polyol (a1) is a multivalent valence of a polyvalent carboxylic acid having an alkylene group having 5 to 20 carbon atoms. A condensed polymer of a carboxylic acid component and a polyvalent alcohol component. The active energy ray-curable composition according to any one of claims 1 to 3, wherein the polyester-based polyol (a1) has a number average molecular weight of 500 to 12,000. The active energy ray-curable composition according to any one of claims 1 to 4, wherein the urethane (meth) acrylate (A) has a weight average molecular weight of 1,000 to 100,000. The active energy ray-curable composition according to any one of claims 1 to 5, further comprising an ethylenically unsaturated monomer (wherein the aforementioned urethane (meth) acrylate (A) except). An active energy ray-curable adhesive composition comprising the active energy ray-curable composition according to any one of claims 1 to 6. A binder which is obtained by curing an active energy ray-curable adhesive composition according to claim 7 of the patent application. An adhesive sheet which is laminated on a substrate sheet and has a binder as described in claim 8 of the patent application. A urethane (meth) acrylate, a polyester-based polyol comprising a polyvalent carboxylic acid component of a polyvalent carboxylic acid having a carbon number of 5 to 20 and a polyvalent alcohol component (a1), a reaction product of a polyisocyanate (a2) and a hydroxyl group-containing (meth) acrylate (a3).