TWI665228B - Active energy ray-curable composition, active energy ray-curable adhesive composition, adhesive and adhesive sheet, and novel urethane (meth) acrylate - Google Patents

Abstract

An object of the present invention is to provide an urethane (meth) acrylate-containing active energy ray-curable composition having a low dielectric constant and excellent compatibility. The present invention relates to an active energy ray-curable composition containing a urethane of a reaction product of a polyester polyol (a1), a polyisocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3). The dielectric constant of the (meth) acrylate (A) and the urethane (meth) acrylate (A) is 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 adhesive composition containing the same, an adhesive using the aforementioned active energy ray-curable adhesive composition, and an adhesive sheet. Specifically, this active energy ray-curable composition contains a urethane (meth) acrylate having a low dielectric constant and excellent compatibility.

The invention also relates to novel urethane (meth) acrylates.

Among the adhesives, there are various adhesives with strong adhesiveness for the purpose of sticking firmly to the adherend for a long time, or various types of adhesives in the form of peeling on the premise of peeling from the adherend after the adhesion. The form is designed to be used for the most suitable adhesive for each field.

Conventionally, as adhesives for display parts, electronic parts, and optical materials, for example, urethanes known to contain polyols, polyisocyanates, and (meth) acrylates containing hydroxyl groups are reacted. An ester (meth) acrylate, and an adhesive that is cured by irradiation with active energy rays. As the polyol, a polyester polyol obtained by condensing a polyvalent carboxylic acid and a polyvalent alcohol is known, and among them, adipic acid is used as the carboxylic acid (for example, refer to Patent Document 1).

In recent years, in particular for optical component applications, and more particularly for touch panel applications, in addition to adhesion and moisture and heat resistance, in order to suppress malfunction of the touch panel due to noise generated by display components and other peripheral components, , Requires a low dielectric constant adhesive.

For example, a resin composition for an ultraviolet curable adhesive is disclosed as a low-dielectric-constant adhesive containing a hydrogenated polybutadiene polyol, a polyisocyanate, and a hydroxyl group-containing (meth) acrylate. Urethane (meth) acrylate (for example, refer to patent document 2).

[Prior technical literature] [Patent Literature]

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

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

However, as disclosed in the above Patent Document 1, a urethane (meth) acrylate obtained by reacting an adipic acid-based polyester polyol, a polyisocyanate, and a hydroxyl-containing (meth) acrylate is used. The electric constant is usually as high as 8.0, and it is not suitable for optical components to suppress the malfunction of the touch panel and cannot meet the required performance.

Further, the urethane (meth) acrylate, which is formed by reacting a hydrogenated polybutadiene polyol, a polyisocyanate, and a hydroxyl group-containing (meth) acrylate, described in Patent Document 2, generally has a low dielectric constant. Up to 3.0, but because the hydrogenated polybutadiene polyol has low polarity, the resulting urethane (methyl) Acrylate itself is also low in polarity and has insufficient compatibility with other monomers or resins, and therefore has disadvantages such as a lack of freedom in material selection, and difficulty in handling.

Under the circumstances, the present invention aims to provide an urethane (meth) acrylate-containing active energy ray-curable composition having a low dielectric constant and excellent compatibility. Furthermore, an active energy ray-curable adhesive composition containing the active energy ray-curable composition, and an adhesive, an adhesive sheet using the same, and a novel urethane (meth) acrylate are also provided.

However, as a result of intensive studies by the present inventors in view of the foregoing, the inventors have found that in an active energy ray-curable composition containing a urethane (meth) acrylate obtained by reacting a polyester polyol When the dielectric constant of the urethane (meth) acrylate is equal to or less than a specific value, an adhesive having a low dielectric constant and excellent compatibility is obtained, and the present invention is obtained.

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

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

[2] The active energy ray-curable composition according to [1], wherein the content X of the oxygen atom in the repeating structural unit of the polyester polyol (a1) is 0.35 or less. The content ratio 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 polyol (a1)

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

c: Number of oxygen atoms in the repeating structural unit of the polyester polyol (a1)

[3] The active energy ray-curable composition according to [1] or [2], wherein the polyester polyol (a1) is a polyvalent carboxylic acid containing an alkylene group having 5 to 20 carbon atoms A polycondensation polymer 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 number average molecular weight of the polyester polyol (a1) is 500 to 12,000.

[5] The active energy ray-curable composition according to any one of [1] to [4], wherein the weight average molecular weight of the urethane (meth) acrylate (A) is 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 urethane (methyl ) Except acrylate (A)).

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

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

[9] An adhesive sheet, wherein the adhesive according to [8] is laminated on a base material sheet.

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

For example, the active energy ray-curable composition according to the present invention can obtain an adhesive composition having a low dielectric constant and excellent compatibility. These cured adhesives are useful as adhesives for optical components, and are particularly suitable for Touch panel applications.

Hereinafter, the present invention will be described in detail.

Moreover, in the present invention, (meth) acrylic acid means acrylic acid and / or methacrylic acid, (meth) acryl group ((meth) acryl) represents acrylic acid group and / or methacrylic acid group, and (meth) (Meth) acryloyl means acryl and / or methacryl, and (meth) acrylate means acrylate and / or methacrylate. 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.

In this specification, "~" is used to indicate a numerical range, and numerical values described before and after are used to include a lower limit value and an upper limit value.

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 active energy ray-curable composition having a formate (meth) acrylate (A) and a dielectric constant of the urethane (meth) acrylate (A) of 7.0 or less.

Here, the above-mentioned dielectric constant indicates a value of the degree of polarization of a substance to which an electric field is applied.

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

(test methods)

An active energy ray-curable composition containing 4 parts by weight of 1-hydroxy-cyclohexyl-phenyl-ketone as a photopolymerization initiator and 100 parts by weight of a urethane (meth) acrylate as a photopolymerization initiator, and The cured film thickness is 150 μm. Use an applicator to apply to an untreated polyethylene terephthalate (PET) film (thickness 50 μm). Leave the solvent in a dryer at 60 ° C for 10 minutes to allow the solvent to pass through. Volatile. Thereafter, a polyethylene terephthalate (PET) film (thickness: 50 μm) was laminated from the top to the surface of the active energy ray-curable composition, and a desk UV irradiation device (manufactured by EYE GRAPHICS, "conveyor belt ( conveyor type desktop irradiation device ") under the conditions of 80W / cm (high-pressure mercury lamp) x 18cmH x 2.04m / min x 3Pass (cumulative exposure of 2,400mJ / cm ² ), the cured cured film is irradiated with ultraviolet rays from the buildup side A test piece for measuring the dielectric constant was cut into 7 cm × 7 cm.

For the test piece for measuring the dielectric constant, an HP4284A Precision LCR Meter (manufactured by Agilent) was used to measure the capacitance by sandwiching the test piece between electrodes and applying an electric field at a frequency of 1 MHz. The change in capacitance between the electrodes was used 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.

Examples of the polyester polyol (a1) of the present invention include a condensation polymer (condensation polymer) of a polyvalent alcohol component and a polyvalent carboxylic acid component, and ring-opening polymerization of a cyclic ester (lactone) component. Substances, and reactants caused by three types of components: 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. Ethylene 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, cyclohexanediols (1, 4-cyclohexanediol, etc.), bisphenols (bisphenol A, etc.), divalent alcohols; glycerol, trimethylolpropane, trimethylolethane, and other trivalent alcohols; sugar alcohols (wood Sugar alcohol, sorbitol) and the like. Among these, a divalent alcohol is preferred from the viewpoint of excellent versatility, and particularly preferred are ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, and 1,4-tetramethylene. Diol, 2-methyl-1,3-trimethylene glycol, neopentyl glycol.

These can 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, azelaic acid, sebacic acid, and twelve Aliphatic dicarboxylic acids such as mandelic acid; alicyclic dicarboxylic acids such as 1,4-cyclohexanedicarboxylic acid; terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalene Aromatic dicarboxylic acids such as dicarboxylic acid, terephthalic acid, trimellitic acid, and the like. These Among them, from the viewpoint of less yellowing, aliphatic dicarboxylic acids are preferred, and succinic acid, adipic acid, and sebacic acid are particularly preferred.

These can 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, from the viewpoint of low dielectric properties, as the polyester polyol (a1), it is preferred that the content ratio X of the oxygen atom in the repeating structural unit of the polyester polyol (a1) is 0.35 or less. The content ratio 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 polyol (a1)

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

c: Number of oxygen atoms in the repeating structural unit of the polyester polyol (a1)

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

In this case, since the formula (1) is a = 8, b = 112, and c = 4, the oxygen atom content rate X = 0.37 in the repeating structural unit represented by the formula (1).

From the viewpoint of low dielectric properties, it is preferred that the polyvalent carboxylic acid component constituting the polyester polyol (a1) contains an alkylene having 5 to 20 carbon atoms. A group of polyvalent carboxylic acids having a carbon number of 6 to 18 is more preferred, and a group of polyvalent carboxylic acids having an alkylene group of 7 to 16 is particularly preferred. The polyester polyol (a1) is more preferably a polycondensation polymer of a polyvalent carboxylic acid component and a polyvalent alcohol component containing a polyvalent carboxylic acid having an alkylene group having 5 to 20 carbon atoms.

When the number of carbons of the alkylene group of the polyvalent carboxylic acid is too small, the dielectric constant tends to be high. When the number of carbons is too large, the crystallinity is high, and the operation is difficult.

Specific examples of the polyvalent carboxylic acid having an alkylene group having 5 to 20 carbon atoms include pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanoic acid, eicosanoic acid, and iso Eicosanoic 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 dielectricity, it is preferable to contain 10 to 100 mol% with respect to the entire polyvalent carboxylic acid component. The best is 20 to 100 mol%, the particularly good is 25 to 100 mol%, and the particularly good is 30 to 100 mol%.

When the content ratio of the polyvalent carboxylic acid having an alkylene group having 5 to 20 carbon atoms is too small with respect to the entire polyvalent carboxylic acid as a whole, the dielectric constant tends to increase.

The number of hydroxyl groups contained in the polyester polyol (a1) is preferably 2 to 5, more preferably 2 to 3, and even more preferably 2 per molecule. When the number of hydroxyl groups is too large, gelation tends to be easily caused during the reaction.

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

If the number average molecular weight is too large, the viscosity tends to be high and the handleability tends to decrease. If the number average molecular weight is too small, it tends to be difficult to obtain sufficient adhesion.

In addition, the said number average molecular weight is a value calculated | required by the following.

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

The hydroxyl value of the polyester polyol (a1) is preferably 10 to 400 mgKOH / g, particularly preferably 20 to 300 mgKOH / g, and even more preferably 30 to 250 mgKOH / g. When the hydroxyl value is too high, the urethane (meth) acrylate tends to have a lower molecular weight and the adhesiveness tends to decrease, and when it is too low, it tends to have a higher viscosity and lower operability.

The 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, xylylene diisocyanate, Aromatic polyisocyanates such as tetramethylxylylene diisocyanate, phenylene diisocyanate, naphthalene diisocyanate; pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate Aliphatic polyisocyanates such as lysine diisocyanate, lysine triisocyanate; hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1 Alicyclic polyisocyanates such as 1,3-bis (isocyanatemethyl) cyclohexane, or the ternary or multimeric compounds of these polyisocyanates, urethane-type polyisocyanates, biuret-type Polyisocyanate, water-dispersible polyisocyanate, etc.

Among these, from the viewpoint of excellent reaction stability, diisocyanate is preferred, and pentamethylene diisocyanate and hexamethylene diisocyanate are particularly preferred. Aliphatic polyisocyanates such as cyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate; hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, Aliphatic polyisocyanates such as norbornene diisocyanate and 1,3-bis (isocyanatemethyl) cyclohexane are more preferably hydrogenated xylylene dimethide from the point of excellent reactivity and versatility. Isocyanate, isophorone diisocyanate.

Moreover, the said polyisocyanate can be used individually by 1 type or in combination of 2 or more types.

Examples of the hydroxyl-containing (meth) acrylate (a3) include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 2-hydroxy (meth) acrylate (Meth) acrylic acid hydroxyl groups having 2 to 20 (preferably 2 to 18) carbon atoms in alkyl groups such as butyl ester, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate Alkyl ester, 2-hydroxyethylpropenylsulfonate, 2- (meth) propenyloxyethyl-2-hydroxypropyl phthalate, caprolactone modified (meth) acrylic acid 2-hydroxyethyl ester, dipropylene glycol (meth) acrylate, fatty acid modification-glycidyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate , 2-hydroxy-3- (meth) acryloxypropyl (meth) acrylate and other (meth) acrylates containing one ethylenically unsaturated group; glycerol di (meth) acrylate, 2-hydroxy-3-propenyl-oxypropyl methacrylate and other (meth) acrylates containing two ethylenically unsaturated groups; pentaerythritol tri (meth) acrylate, caprolactone modified Pentaerythritol tri (meth) acrylate Ethylene oxide modified pentaerythritol tri (meth) acrylate, dipentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol penta (tetramethyl) acrylate, ethylene oxide modified dipentaerythritol pentaerythritol five ( Containing 3 or more ethyl meth) acrylates Ethylene unsaturated (meth) acrylate. The said (meth) acrylate (a3) which has a hydroxyl group can be used individually by 1 type or in combination of 2 or more types.

Among these, from the viewpoint of excellent flexibility of the adhesive layer, a hydroxyl-containing (meth) acrylate containing one ethylenically unsaturated group is preferred, and 2-hydroxyethyl (meth) acrylate is more preferred (Meth) such as 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, etc. It is preferable to use 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate especially from a viewpoint that hydroxyalkyl acrylate is excellent also in reactivity and versatility.

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

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 reacted together, ( 2) A method of reacting a hydroxyl group-containing (meth) acrylate (a3) in a reaction product obtained by reacting a polyester polyol (a1) and a polyisocyanate (a2) in advance.

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

When producing a urethane (meth) acrylate (A), a polyester polyol (a1) and a polyisocyanate (a2) are reacted in advance. A method for reacting the hydroxyl group-containing (meth) acrylate (a3) in the obtained reaction product will be described.

For the reaction of the polyester polyol (a1) and the polyisocyanate (a2), a known reaction means can be used. In this case, for example, the molar ratio of the isocyanate group in the polyisocyanate (a2) to the hydroxyl group in the polyester polyol (a1) is usually 2n: (2n-2) (n is an integer of 2 or more) To the extent that an isocyanate group-containing urethane (meth) acrylate containing a terminal isocyanate group can be obtained. After the compound is obtained, addition to the hydroxyl group-containing (meth) acrylate (a3) can be performed.成 反应。 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 performed by a known reaction means. .

The molar ratio of the reaction product between the reaction product and the hydroxyl group-containing (meth) acrylate (a3) is, for example, that the reaction product has two isocyanate groups and the hydroxyl group (meth) acrylate (a3) contains a hydroxyl group. In the case of one reaction product, the hydroxyl group-containing (meth) acrylate (a3) is approximately 1: 2, the reaction product has three isocyanate groups, and the hydroxyl group-containing (meth) acrylate ( When there is one hydroxyl group in a3), the reaction product: (meth) acrylic acid ester (a3) containing a hydroxyl group is about 1: 3.

In the addition reaction between the reaction product and the hydroxyl group-containing (meth) acrylate (a3), the reaction is completed when the content of the residual isocyanate group in the reaction system becomes 0.3% by weight or less, and an amine group is obtained. Formate (meth) acrylate (A).

The polyester polyol (a1) and polyisocyanate (a2) In the reaction, and further the reaction between the reaction product and the hydroxyl group-containing (meth) acrylate (a3), it is preferred that a catalyst be used for the purpose of promoting the reaction. Examples of such a catalyst include dibutyltin dilaurate, dibutyltin diacetate, trimethyltin peroxide, tetra-n-butyltin, zinc diethylpyreneacetone, and zirconium triacetate ) Organometallic compounds such as ethyl acetoacetate, zirconium acetoacetate, zirconium acetoate, zinc hexanoate, zinc octoate, zinc stearate, zirconium 2-ethylhexanoate, naphthenic acid Metal salts 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 In addition to amine catalysts such as morpholine and N-ethylmorpholine, bismuth nitrate, bismuth bromide, bismuth iodide, bismuth sulfide, etc., dibutylbismuth dilaurate, dioctylbismuth dilaurate, etc. Organic bismuth compound, or bismuth 2-ethylhexanoate, bismuth naphthenate, bismuth isodecanoate, bismuth neodecanoate, bismuth laurate, bismuth maleate, bismuth stearate , Bismuth oleate, bismuth linoleate, bismuth acetate, bis (bis neodecanoate), bismuth salicylate, digalloate 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 can be used individually by 1 type or in combination of 2 or more types.

In addition, in the reaction between the polyester polyol (a1) and the polyisocyanate (a2), and in the reaction between the reaction product and the hydroxyl group-containing (meth) acrylate (a3), it is also possible to use a resin having no isocyanate as required. The organic solvent of the functional group having a radical reaction is, for example, 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 family or an ethylenically unsaturated monomer (for example, an ethylenically unsaturated monomer (B) as described below) may be mentioned.

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

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

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

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

The weight average molecular weight is a weight average molecular weight obtained by converting the molecular weight of standard polystyrene into a high-speed liquid chromatography (manufactured by Showa Denko, "Shodex GPC system-11") using a column: Shodex GPC KF -806L (Excluding limiting molecular weight: 2 × 10 ⁷ , separation range: 100 ~ 2 × 10 ⁷ , theoretical plate number 10,000 plates / piece, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm ) The value measured in series of three.

Moreover, as for the viscosity of the urethane (meth) acrylate (A) of the present invention, a viscosity at 60 ° C. of 1,000 to 1,000,000 mPa is preferred. s, especially good for 2,000 ~ 900,000mPa. s, more preferably 3,000 to 800,000 mPa. s. If the viscosity is too high, handling tends to be difficult, and if it is too low, control of film thickness during coating tends to be difficult.

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

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

Examples of the ethylenically unsaturated monomer (B) used in the present invention include a monofunctional monomer, a bifunctional monomer, and a trifunctional or higher monomer.

Examples of the monofunctional monomer include styrene-based 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, 3-chloro-2-hydroxypropyl (meth) acrylate, glyceryl mono (meth) acrylate, glycidyl (meth) acrylate, laurate (meth) acrylate, Cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, tricyclodecyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxy (meth) acrylate Ethyl ester, dicyclopentyl (meth) acrylate, (2-methyl-2-ethyl-1,3-dioxolane-4-yl) -methyl (meth) acrylate, (methyl Propyl) cyclohexanespiro-2- (1,3-dioxolane-4-yl) -methyl, (meth) propane 3-ethyl-3-oxetanyl enoate, γ-caprolactone (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate , Octyl (meth) acrylate, nonyl (meth) acrylate, (meth) Decyl acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, n-stearate (meth) acrylate, benzyl (meth) acrylate, phenol oxide modification ( (n = 2) (meth) acrylate, nonylphenol propylene oxide modified (n = 2.5) (meth) acrylate, 2- (meth) acryloxyethyl acid phosphate, 2- ( Hemi (meth) acrylate, furyl (meth) acrylate, tetrahydrofuran (meth) acrylate Carbitol (meth) acrylate, benzyl (meth) acrylate, butoxyethyl (meth) acrylate, allyl (meth) acrylate, (meth) acrylfluorenylmorpholine, polyoxyl (Meth) acrylic acid ester-based monomers such as vinyl vinyl secondary alkyl ether acrylate, 2-hydroxyethylacrylamide, N-hydroxymethyl (meth) acrylamide, N-vinylpyrrolidone, 2-vinylpyridine, vinyl acetate, etc.

Examples of the bifunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and polyethylene glycol. Alcohol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butanediol di (meth) acrylate, new Pentylene glycol di (meth) acrylate, ethylene oxide modified bisphenol A type di (meth) acrylate, propylene oxide modified bisphenol A type di (meth) acrylate, cyclohexanedi Methanol di (meth) acrylate, ethoxylated cyclohexane dimethanol di (meth) acrylate, dimethylol dicyclopentane di (meth) acrylate, tricyclodecane dimethanol bis (methyl) ) Acrylate, 1,6-hexanediol di (meth) acrylate, glyceryl di (meth) acrylate, pentaerythritol di (meth) acrylate, ethylene glycol diglycidyl ether bis (methyl) Acrylate, diethylene glycol diglycidyl ether di (methyl) Acrylate, diglycidyl phthalate di (meth) acrylate, hydroxytrimethylacetic acid modified neopentyl glycol di (meth) acrylate, isocyanuric acid ethylene oxide 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, tri (meth) acryloxyethoxytrimethylolpropane, glycerol polyglycidyl ether poly (meth) acrylate, isocyanuric acid ethylene oxide Alkane 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, ethylene oxide Alkanes modified pentaerythritol tri (meth) acrylate, ethylene oxide modified pentaerythritol tetra (meth) acrylate, epoxidized glycerol triacrylate, and the like.

In addition, a Michael adduct of acrylic acid or a 2-propenyloxyethyl dicarboxylic acid monoester may also be used in combination. Examples of the Michael adduct of acrylic acid include acrylic acid binary and methacrylic acid. Binary bodies, acrylic ternary bodies, methacrylic ternary bodies, acrylic quaternary bodies, methacrylic quaternary bodies, and the like.

Examples of the 2-propenyloxyethyl dicarboxylic acid monoester are carboxylic acids having specific substituents, and examples include 2-propenyloxyethyl succinic acid monoester and 2-methacrylic acid oxyethyl Succinic acid monoester, 2-acrylic acid ethyl phthalate monoester, 2-methacrylic acid ethyl phthalate monoester, 2-acrylic acid ethyl hexahydrophthalic acid monoester , 2-methacrylic acid oxyethyl hexahydrophthalic acid monoester, and the like. Yet In addition, other oligoester acrylates may be mentioned.

The content of the ethylenically unsaturated monomer (B) is preferably 5 to 900 parts by weight, particularly preferably 10 to 600 parts by weight, based on 100 parts by weight of the urethane (meth) acrylate (A). Still more preferably, it is 15 to 400 parts by weight. When the content is too large, the viscosity tends to decrease and the adhesive force tends to decrease, and when it is too small, the viscosity tends to increase and the coatability tends to decrease.

In the present invention, it is preferred that the active energy ray-curable composition further contains a photopolymerization initiator (C), and the photopolymerization initiator (C) may be any one that can generate free radicals due to the action of light. Specially limited. Examples include diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1-one, benzyldimethylacetal, and 4- (2-hydroxyethoxy) Phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenyl ketone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl -1-propane-1-one, 2-methyl-2-morpholinyl (4-thiomethylphenyl) propane-1-one, 2-benzyl-2-dimethylamino-1- ( Acetophenones such as 4-morpholinylphenyl) butanone, 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] acetone oligomers; benzoin, Benzoin methyl ether, Benzoin ethyl ether, Benzoin isopropyl ether, Benzoin isobutyl ether and other benzoin; benzophenone, o-benzoyl methyl benzoate, 4-phenylbenzophenone, 4-benzylidene-4'-methyl-diphenylsulfide, 3,3 ', 4,4'-tetrakis (third butylperoxycarbonyl) diphenyl Methyl ketone, 2,4,6-trimethylbenzophenone, 4-benzylidene-N, N-dimethyl-N- [2- (1-keto (oxo) -2-propenyloxy (Ethyl) ethyl] benzyl ammonium bromide, (4-benzylidene benzyl) trimethylammonium chloride and other benzophenones; 2-isopropylthioxanthone, 4-isopropylthio Tonone, 2,4-diethylthioxanthone 2,4-dichlorothioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy) -3,4-dimethyl-9H-thio Tonone-9-ketomethyl chloride, etc. Ton ketones; 2,4,6-trimethylbenzylidene-diphenylphosphine oxide, bis (2,6-dimethoxybenzylidene) -2,4,4-trimethyl- Phenylphosphine oxides such as pentylphosphine oxide, bis (2,4,6-trimethylbenzylfluorenyl) -phenylphosphine oxide, etc .; etc. Moreover, these photopolymerization initiators may be used individually by 1 type, and may use 2 or more types together.

Moreover, as an auxiliary agent of these photopolymerization initiators (C), triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Michlerone), 4 , 4'-Diethylaminobenzophenone, 2-dimethylaminoethyl benzoate, ethyl 4-dimethylaminobenzoate, 4-dimethylaminobenzoic acid (n-butyl (Oxy) ethyl ester, 4-dimethylaminobenzoic acid isoamyl ester, 4-dimethylaminobenzoic acid 2-ethylhexyl ester, 2,4-diethylthioxanthone, 2,4- Diisopropylthioxanthone and the like. These additives may be used alone or in combination of two or more.

The content of the photopolymerization initiator (C) is carbamic acid relative to the urethane (meth) acrylate (A) (in the case where the ethylenically unsaturated monomer (B) is further contained). 100 parts by weight of the ester (meth) acrylate (A) and the ethylenically unsaturated monomer (B)), preferably 1 to 10 parts by weight, and particularly preferably 2 to 5 parts by weight. If the content is too small, the curing rate tends to decrease, and if it is too large, the curing property will not be improved but the economy will tend to decrease.

The active energy ray-curable composition of the present invention is not only a urethane (meth) acrylate (A), an ethylenically unsaturated monomer (B), a photopolymerization initiator (C), etc., but also Antioxidants, flame retardants, antistatic agents, fillers, leveling agents, stabilizers, reinforcing agents, bleaching agents, etc. can be added. Further, as the crosslinking agent, a compound having a crosslinking effect due to heat can be used, and specifically, an epoxy compound, an aziridine compound, a melamine compound, an isocyanate compound, and a chelate compound can be used. Moreover, as a hydrolysis inhibitor, Carbodiimide can also be used.

Moreover, according to the active energy ray-curable composition of the present invention, in order to adjust the viscosity at the time of coating, alcohols such as methanol, ethanol, propanol, n-butanol, and isobutanol, etc. may be used for dilution; Acetone, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone and other ketones; ethyl cyrus and other cyrus; aromatics such as toluene and xylene; propylene glycol monomethyl ether and the like Alcohol ethers; Acetic esters such as methyl acetate, ethyl acetate, butyl acetate; Dilution solvents such as diketol, but based on the possibility of the solvent remaining in the coating film or the possibility of volatilization of the curing component during drying, it is preferred It is essentially free of solvents.

In addition, the fact that the solvent is not substantially contained means that it 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 entire active energy ray-curable composition.

The active energy ray-curable composition of the present invention can be used as a coating agent composition for various substrate films, and can be used as an adhesive composition for bonding various components or a surface protection sheet, but it can be used as active energy. The radiation-curable adhesive composition is particularly useful.

Furthermore, the active energy ray-curable adhesive composition of the present invention may contain an adhesion-imparting agent such as polythiol from the viewpoints of suppression of unreacted components and improvement of 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 alkane dithiols having a carbon number of 2 to 20; xylylene Aromatic polythiols such as dithiols, polythiols in which the halogen atom of an alcoholic halogenated alcohol adduct is substituted with a thiol group; a hydrogen sulfide reaction product of a polyepoxide compound Polythiols; 2 to 6 in the molecule Polythiols composed of hydroxy polyhydric alcohols and esterified products of thioglycolic acid, β-thiol propionic acid, or β-thiol butyric acid, etc. These can be used alone or in combination. the above.

The content in the case where the polythiol compound is contained is based on the urethane (meth) acrylate (A) (in the case where the ethylenically unsaturated monomer (B) is further contained, the urethane ( The total of (meth) acrylate (A) and 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 base material sheet or the like as an adhesive sheet for practical use. After being applied to a base material sheet or the like, it is irradiated with active energy rays to become a crosslinked adhesive. And found adhesion.

In addition, in the case where it is not particularly specified, the adhesive sheet includes an adhesive film and an adhesive tape, and is characterized in that the active energy ray-curable adhesive composition of the present invention is laminated with an adhesive.

Further, in the present invention, until the adhesive sheet is attached to the adherend (part), the separator may be separated from the surface area layer of the adhesive for the purpose of contaminating the adhesive.

Examples of the substrate sheet include polyester resins such as polyethylene terephthalate and polybutylene terephthalate; and polymers such as polyethylene, polypropylene, and ethylene-propylene copolymers. Olefin resin; polycarbonate, polyurethane resin, acrylic resin, polystyrene resin, ethylene-vinyl acetate copolymer, polyvinyl chloride, polybutene, polyester, polymethylpentene, acrylonitrile Resin sheets such as butadiene styrene copolymer (ABS), or glass plates. Can also It is used for surface treatment of various substrate sheets through anchoring layer, corona treatment, plasma treatment, etc.

As the above-mentioned separation sheet, a resin sheet or a substrate such as paper, cloth, nonwoven fabric, or the like as described above, which is a base material sheet, may be subjected to a release treatment.

When an adhesive layer is formed on a base material sheet, a direct coating method in which an active energy ray-curable adhesive composition is directly applied to the base material sheet, or an active energy ray-curable adhesive is exemplified. A transfer coating method or the like in which the composition is applied to a separation sheet and then adhered to a substrate sheet.

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

When the coated active energy ray-curable composition contains a solvent, the coated active energy ray-curable composition is dried after coating. The drying conditions are set to be sufficient to sufficiently volatilize the solvent in the coated active energy ray-curable composition. The drying temperature and drying time are sufficient. The drying temperature is usually 40 to 100 ° C, and particularly preferably 50 to 90 ° C. The drying time is preferably 1 to 60 minutes in consideration of production suitability.

In addition, when the active energy ray-curable adhesive composition is a solid or a highly viscous liquid, the active energy ray-curable composition can be heated without adjusting the viscosity with a solvent to reduce the viscosity and then coated by the above method. Hot melt method of cloth.

After the active energy ray-curable adhesive composition of the present invention is applied to a substrate sheet and dried, the active energy ray is irradiated with active energy rays to become a crosslinked adhesive, and further becomes an adhesive sheet.

Regarding the irradiation of active energy rays, in the direct coating method, an active energy ray-curable adhesive composition may be coated on a substrate sheet and heated and dried. Then, the active energy rays may be irradiated, and then the separation sheet may be bonded. After the base material sheet is coated with an active energy ray-curable adhesive composition and heated and dried, the separation sheet is attached, and then the active energy ray is irradiated. On the other hand, in the transfer coating method, an active energy ray-curable adhesive composition may be coated on a separation sheet and heated and dried, and then the active energy ray may be irradiated and then bonded to a base material sheet. After the separation sheet is coated with an active energy ray-curable adhesive composition and dried by heating, it is attached to a base material sheet, and thereafter, the active energy ray is irradiated.

As the active energy rays, far-ultraviolet rays, ultraviolet rays, near-ultraviolet rays, infrared rays, and other electromagnetic waves, X-rays, and γ-rays can be used. In addition, electron beams, proton rays, and neutral beams can also be used to obtain them from curing speed and irradiation devices In consideration of easiness, price, etc., curing by ultraviolet irradiation is preferred. When electron beam irradiation is performed, curing can be performed without using a photopolymerization initiator (C).

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

After UV irradiation, it can also be heated if necessary to seek curing. complete.

In addition, the thickness of the adhesive layer formed on the base material sheet after irradiating active energy rays can be appropriately set according to the application, and is usually 5 to 300 μm, preferably 10 to 250 μm. If the thickness of the adhesive layer is too thin, the adhesiveness tends to be difficult to stabilize, and if it is too thick, the adhesive tends to be easily left.

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

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

Moreover, 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. It is preferably 17.5 ~ 50N / 25mm.

Since the dielectric constant of the urethane (meth) acrylate of the present invention is low, the dielectric constant of the active energy ray-curable composition of the present invention containing it is also low, and the active energy ray-curable composition containing the same The active energy ray-curable adhesive composition or its cured adhesive is useful as an adhesive for optical components such as optical devices such as touch panels or optical recording media, and is particularly suitable for use with touch panels. Application of structural members, organic electroluminescence display sealing, etc.

Examples

The following examples illustrate the present invention more specifically, as long as it is not The case beyond the gist of the present invention is not limited to the following examples. In addition, "part" and "%" are based on weight in the example.

<Example 1>

[Synthesis of Urethane Acrylate (A-1)]

In a 4-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen blowing inlet, 12.6 g (0.057 mol) of isophorone diisocyanate, and a bifunctional polyester polyol (hydroxyl value 60.3 mgKOH / g, quantity average) were added. Molecular weight 2,000, content of oxygen atom in repeating structural unit X = 0.26, polyvalent carboxylic acid component: 100 mole% of sebacic acid) 84.7 g (0.046 mole), dibutyltin laurate as a reaction catalyst 0.02g, reacted at 80 ° C for 6 hours, then added 2.7g (0.023 moles) of 2-hydroxyethyl acrylate and 0.04g of 2,6-di-tert-butylcresol as a polymerization inhibitor, and reacted at 60 ° C for 3 hours. The reaction was completed when the residual isocyanate group became 0.3%, and a urethane acrylate (A-1) (weight average molecular weight (Mw); 30,000) was obtained.

About the obtained urethane acrylate (A-1), the following evaluations were performed.

<Dielectric constant>

Based on 100 parts by weight of urethane acrylate (A-1), 43 parts by weight of ethyl acetate was uniformly mixed as 1-hydroxy-cyclohexyl-phenyl-one as a photopolymerization initiator (BASF JAPAN Co., Ltd. ("IRGACURE184") 4 parts were uniformly mixed to obtain an active energy ray-curable composition.

(Production of a test piece for measuring the dielectric constant)

The active energy ray-curable composition obtained above was applied to an untreated polyethylene terephthalate (PET) film (thickness 50 μm) with an applicator so that the film thickness after curing became 150 μm, and The solvent was left in the dryer at 60 ° C for 10 minutes. Thereafter, an untreated polyethylene terephthalate (PET) film (thickness: 50 μm) was laminated from above on the side of the active energy ray-curable composition, and a desktop UV irradiation device (manufactured by Eye Graphics Corporation, Type desktop irradiation device '') under the conditions of 80W / cm (high-pressure mercury lamp) × 18cmH × 2.04m / min × 3Pass (cumulative irradiation amount 2,400mJ / cm ² ), the ultraviolet light is irradiated from the build-up side, and the cured cured film is cut into 7 cm x 7 cm to obtain a test piece for measuring the dielectric constant.

(test methods)

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

(Evaluation criteria)

○; below 7.0

×; greater than 7.0

<Compatibility>

The urethane acrylate (A-1) and the following ethylenically unsaturated monomers are individually mixed in such a manner that the weight ratio becomes 1; 1, and after thorough mixing, the appearance of the compound solution is 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 criteria)

○; The mixing solution is uniform.

×; The mixing solution was uneven.

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

<Adhesiveness>

With respect to 100 parts of the urethane acrylate (A-1), 81 parts of phenoxyethyl acrylate as the ethylenically unsaturated monomer (B) are used as the 1-hydroxy-ring of the photopolymerization initiator. 7.2 parts of hexyl-phenyl-one (manufactured by BASF JAPAN Co., Ltd .; "IRGACURE184") were uniformly mixed to obtain an active energy ray-curable adhesive composition.

(Production of Adhesive Sheets for Measuring Adhesion)

The obtained active energy ray-curable adhesive composition was applied to an easily-adhesive polyethylene terephthalate (PET) film (thickness 125 μm) with an applicator so that the cured film thickness became 175 μm. A desktop UV irradiation device (produced by EYE GRAPHICS, "conveyor-type desktop irradiation device") at 80 W / cm (high-pressure mercury lamp) x 18 cmH x 2.04 m / min x 3 Pass (cumulative exposure 2,400 mJ / cm ² ) UV rays were irradiated and cured under the conditions described above, thereby obtaining an adhesive sheet for measuring adhesive force.

<experiment method>

The obtained bonded sheet was cut into 25 mm × 100 mm, and then pressed back and forth twice with a 2 kg rubber roller in a glass plate as a to-be-adhered body at 23 ° C. and a relative humidity of 50% to produce a test sheet. . Place this test sheet in the same ring After being left to stand for 30 minutes in an environment, a 180-degree peel test was performed at a peel speed of 0.3 m / min, and the adhesive force (N / 25 mm) was measured and evaluated by the following criteria.

(Evaluation criteria)

○; above 17.5N / 25mm

△; 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 blowing inlet, 11.9 g (0.054 mol) of isophorone diisocyanate, a bifunctional polyester polyol (hydroxyl value 56.0 mgKOH / g, quantity average) Molecular weight 2,000, content of oxygen atoms in repeating structural unit X = 0.34, polyvalent carboxylic acid component: 35 mole% of sebacic acid) 85.6 g (0.043 mole), dibutyltin laurate as a reaction catalyst 0.02g, reacted at 80 ° C for 6 hours, then added 2.5g (0.022 mole) of 2-hydroxyethyl acrylate and 0.04g of 2,6-di-tert-butylcresol as a polymerization inhibitor, and reacted at 60 ° C for 3 hours. The reaction was completed when the residual isocyanate group became 0.3%, and the urethane acrylate (A-2) was obtained (weight average molecular weight (Mw); 38,000).

The obtained urethane acrylate (A-2) was evaluated for dielectric properties and compatibility in the same manner as in Example 1. The active energy ray-curable adhesive composition containing a urethane acrylate (A-2) was evaluated in the same manner as in Example 1.

<Comparative Example 1>

[Synthesis of Urethane Acrylate (A'-1)]

In a 4-necked flask equipped with a thermometer, a stirrer, a water-cooled condenser, and a nitrogen blowing inlet, 11.8 g (0.053 mol) of isophorone diisocyanate, and a bifunctional polyester polyol (hydroxyl value 55.4 mgKOH / g, quantity average) were added. Molecular weight 2,000, content of oxygen atoms in repeating structural unit X = 0.37, polyvalent carboxylic acid component: 100 mole% of adipic acid) 85.7g (0.042 mole), dibutyltin laurate as a reaction catalyst 0.02g, reacted at 80 ° C for 6 hours, then added 2.5g (0.022 mole) of 2-hydroxyethyl acrylate and 0.04g of 2,6-di-tert-butylcresol as a polymerization inhibitor, and reacted at 60 ° C for 3 hours. The reaction was completed when the residual isocyanate group became 0.3%, and a urethane acrylate (A'-1) (weight average molecular weight (Mw); 26,000) was obtained.

The obtained urethane acrylate (A'-1) was evaluated for dielectric properties and compatibility in the same manner as in Example 1. The active energy ray-curable adhesive composition containing a urethane acrylate (A'-1) was evaluated in the same manner 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 blowing port, 10.1 g (0.045 mol) of isophorone diisocyanate and a bifunctional hydrogenated polybutadiene polyol (hydroxyl value 48.3 mgKOH / g) were added. , Number average molecular weight 2,000) 87.7 g (0.038 mol), 0.02 g of dibutyltin laurate as a reaction catalyst, and after reacting at 80 ° C for 6 hours, 2.2 g of 4-hydroxybutyl acrylate (0.015 mol), 0.04 g of 2,6-di-tert-butylcresol as a polymerization inhibitor was reacted at 60 ° C for 3 hours, and the reaction was terminated at the time when the residual isocyanate group became 0.3% to obtain a urethane acrylate (A'-2 ) (Weight average molecular weight (Mw); 49,000).

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

Next, based on 100 parts by weight of the urethane acrylate (A'-2), 69 parts by weight of isodecyl acrylate as the ethylenically unsaturated monomer (B) was used as 1- 6.8 parts of hydroxy-cyclohexyl-phenyl-one (manufactured by BASF JAPAN Co., Ltd .; "IRGACURE184") were uniformly mixed to obtain an active energy ray-curable adhesive composition, and the adhesiveness was evaluated in the same manner as in Example 1.

The above evaluation results are shown in Table 1 below.

Based on the above evaluation, the urethane acrylates of Examples 1 and 2 having a dielectric constant of 7.0 or less were found to have good appearance and excellent compatibility with the various liquids containing ethylenically unsaturated monomers. In addition, 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, although the urethane (meth) acrylate of Comparative Example 1 having a dielectric constant exceeding 7.0 has excellent compatibility, it has a high dielectric constant and is difficult to apply to an adhesive for optical components.

In addition, the urethane acrylate of Comparative Example 2 in which a polybutadiene-based polyol was used instead of a polyester-based polyol and reacted had a dielectric constant of 7.0 or less. The cases were poorly compatible.

Although the present invention is described with reference to detailed or specific embodiments, various changes or modifications can be made without departing from the spirit and scope of the present invention, which are matters known to those skilled in the art. This application is based on the JP Patent application (Japanese Patent Application No. 2014-233837) for which it applied on November 18, 2014, The content is taken in here as a reference.

[Industrial availability]

Since the active energy ray-curable composition of the present invention has a low dielectric constant, the active energy ray-curable adhesive composition and the adhesive containing the same according to the present invention are used as an optical device or an optical record of a touch panel, for example. Adhesives for optical components such as media are useful, and in particular, they are suitable for use in bonding touch panel structural members, organic electroluminescent display sealing, and the like.

Claims (8)

An active energy ray-curable composition containing a urethane (methyl group) of a reaction product of a polyester polyol (a1), a polyisocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3) ) Acrylate (A), the urethane (meth) acrylate (A) has a dielectric constant of 7.0 or less, a weight average molecular weight of 30,000 to 100,000, and a repeating structure of the polyester polyol (a1) The content X of the oxygen atom in the unit is 0.26 to 0.35; however, the foregoing content 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: the polyester-based polyol (a1) ) The number of oxygen atoms in the repeating structural unit. The active energy ray-curable composition according to item 1 of the patent application range, wherein the polyester polyol (a1) is a polyvalent carboxylic acid containing a polyvalent carboxylic acid having an alkylene group having 5 to 20 carbon atoms. Polycondensation of ingredients and polyvalent alcohol ingredients. The active energy ray-curable composition according to item 1 or 2 of the scope of patent application, wherein the number average molecular weight of the polyester polyol (a1) is 500 to 12,000. The active energy ray-curable composition according to item 1 or 2 of the patent application scope, which further contains an ethylenically unsaturated monomer (B) (except for the aforementioned urethane (meth) acrylate (A) ). An active energy ray-curable adhesive composition containing the active energy ray-curable composition according to any one of claims 1 to 4 of the scope of patent application. A kind of adhesive, such as the adhesive made by curing the active energy ray-curable adhesive composition described in item 5 of the scope of patent application. The invention relates to an adhesive sheet, which is laminated on the base sheet with the adhesive as described in item 6 of the scope of patent application. A urethane (meth) acrylate, a polyester polyol containing a polyvalent carboxylic acid component of a polyvalent carboxylic acid having an alkylene group of 5 to 20 carbon atoms and a polyvalent alcohol component (a1), a reaction product of a polyisocyanate (a2), and a hydroxyl group-containing (meth) acrylate (a3), the weight average molecular weight of which is 30,000 to 100,000, and that of the repeating structural unit of the polyester polyol (a1) The content ratio X of the oxygen atom is 0.26 to 0.35; however, the content ratio X is a value represented by the following formula (1): X = 16c / (12a + b + 16c) ... (1) a: polyester Number of carbon atoms in the repeating structural unit of the polyol (a1); b: Number of hydrogen atoms in the repeating structural unit of the polyester polyol (a1); c: Repetition of the polyester polyol (a1) The number of oxygen atoms in the structural unit.