KR102245657B1 - Active energy ray-curable pressure sensitive adhesive composition, and pressure sensitive adhesive and pressure sensitive adhesive sheet using same - Google Patents

Abstract

Polyvalent isocyanate compound (a1), a hydroxyl group-containing (meth)acrylate compound (a2), and a polyol compound (a3) are reacted to form a urethane (meth)acrylate compound having a weight average molecular weight of 20,000 to 120,000 ( A), and an ethylenically unsaturated monomer (B) (however, except for a urethane (meth) acrylate compound (A)) is an active energy ray-curable pressure-sensitive adhesive composition, and as an ethylenically unsaturated monomer (B), a heterocycle The containing monomer (b1) and the hydroxyl-containing monomer (b2) are contained, and the content ratio (weight ratio) of the heterocyclic-containing monomer (b1) and the hydroxyl-containing monomer (b2) is (b1): (b2) = 25:75 to 80 : An active energy ray-curable pressure-sensitive adhesive composition characterized in that it is 20.

Description

Active energy ray-curable pressure sensitive adhesive composition, pressure sensitive adhesive comprising same, and pressure sensitive adhesive sheet {Active energy ray-curable pressure sensitive adhesive composition, and pressure sensitive adhesive and pressure sensitive adhesive sheet using same}

The present invention relates to an active energy ray-curable pressure-sensitive adhesive composition containing a urethane (meth)acrylate-based compound, a pressure-sensitive adhesive containing the same, and a pressure-sensitive adhesive sheet.

There are various types of pressure-sensitive adhesives, such as a strong-adhesive pressure-sensitive adhesive for the purpose of firmly attaching an adherend for a long period of time, and a peel-type pressure-sensitive adhesive that presupposes peeling from the adherend after sticking. It is designed and used.

Further, for example, in an adhesive used in an optical device such as a touch panel or an optical member such as an optical recording medium, in addition to adhesive strength, transparency, particularly excellent transparency under high temperature and high humidity conditions is required.

As a pressure-sensitive adhesive used for an optical member, for example, Patent Document 1 discloses that a resin composition for an ultraviolet-curable pressure-sensitive adhesive containing a urethane (meth)acrylate resin is excellent in balance between adhesion to a substrate and a holding force.

Patent Document 1 JP 2012-136557 A

By the way, it was difficult to say that the adhesive force of the resin composition for an adhesive of Patent Document 1 was sufficient. In addition, although this resin composition for pressure-sensitive adhesives achieves good heat yellowing resistance, this effect is achieved by adding additives such as stabilizers and antioxidants, and the performance of moisture-and-heat resistance is improved by the pressure-sensitive adhesive resin composition itself. It was not.

Accordingly, it is an object of the present invention to provide a pressure-sensitive adhesive composition for obtaining a pressure-sensitive adhesive that is excellent in balance between adhesive strength and heat-and-moisture resistance under such a background.

However, the inventors of the present invention have conducted extensive research in consideration of such circumstances, and as a result, in an active energy ray-curable pressure-sensitive adhesive composition containing a urethane (meth)acrylate-based compound having a relatively high molecular weight and an ethylenically unsaturated monomer, In the present invention, it was found that by using an active energy ray-curable pressure-sensitive adhesive composition containing a heterocycle-containing monomer (b1) and a hydroxyl group-containing monomer (b2) in a predetermined content ratio, it is possible to obtain a pressure-sensitive adhesive having excellent adhesion and heat-and-moisture resistance in a balance. Completed.

That is, the gist of the present invention is formed by reacting a polyvalent isocyanate compound (a1), a hydroxyl group-containing (meth)acrylate compound (a2), and a polyol compound (a3), and has a weight average molecular weight of 20,000 to 120,000. An active energy ray-curable pressure-sensitive adhesive composition containing a (meth)acrylate-based compound (A) and an ethylenically unsaturated monomer (B) (except for a urethane (meth)acrylate-based compound (A)). The heterocycle-containing monomer (b1) and the hydroxyl group-containing monomer (b2) are contained as the unsaturated monomer (B), and the content ratio (weight ratio) of the heterocycle-containing monomer (b1) and the hydroxyl group-containing monomer (b2) is (b1):( It relates to an active energy ray-curable pressure-sensitive adhesive composition characterized in that b2) = 25:75 to 80:20.

In the present invention, there is also provided a pressure-sensitive adhesive comprising curing the active energy ray-curable pressure-sensitive adhesive composition, and a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed by curing the active energy-ray-curable pressure-sensitive adhesive composition.

According to the active energy ray-curable pressure-sensitive adhesive composition of the present invention, it is possible to obtain a pressure-sensitive adhesive with excellent balance of adhesion and moisture-heat resistance, that is, a pressure-sensitive adhesive that exhibits high adhesion and does not deteriorate transparency even when exposed to moist heat conditions. For example, it is useful as an adhesive used for optical devices such as touch panels and optical members such as optical recording media. The reason why such an effect is obtained is not clear, but it is thought that the use of a urethane (meth)acrylate-based compound (A) having a relatively high molecular weight improves the adhesive strength by increasing the flexibility of the pressure-sensitive adhesive layer. In addition, by combining a heterocycle-containing monomer (b1) and a hydroxyl group-containing monomer (b2) as ethylenically unsaturated monomers (B) in a specific ratio, the balance of cohesion and hydrophilicity can be controlled, so that adhesion and heat resistance to moisture are balanced. It is thought that an excellent adhesive is obtained.

Hereinafter, although this invention is demonstrated in detail, these show an example of a preferable embodiment.

In addition, in the present invention, (meth)acrylic acid is acrylic acid or methacrylic acid, (meth)acrylic is acrylic or methacrylic, (meth)acryloyl is acryloyl or methacryloyl, (meth)acrylate Means acrylate or methacrylate, respectively. In addition, the acrylic resin is a resin obtained by polymerizing a polymerization component containing at least one (meth)acrylate-based monomer.

The active energy ray-curable pressure-sensitive adhesive composition of the present invention contains a urethane (meth)acrylate-based compound (A) and an ethylenically unsaturated monomer (B).

[Urethane (meth) acrylate compound (A)]

The urethane (meth)acrylate compound (A) used in the present invention is formed by reacting a polyvalent isocyanate compound (a1), a hydroxyl group-containing (meth)acrylate compound (a2), and a polyol compound (a3). .

Examples of the polyvalent isocyanate compound (a1) include tolylene diisocyanate, diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, xylene diisocyanate, tetramethylxylene diisocyanate, and phenylene diisocyanate. , Aromatic polyisocyanates such as naphthalene diisocyanate; aliphatic polyisocyanates such as pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, lysine diisocyanate, and lysine triisocyanate; alicyclic diisocyanates (for example, Alicyclic polyisocyanates such as isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, norbornene diisocyanate), or trimeric compounds or multimer compounds of these polyisocyanates; allophanate poly An isocyanate, a biuret-type polyisocyanate, etc. are mentioned.

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

Among these, from the viewpoint of less yellowing, aliphatic diisocyanates such as pentamethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, and lysine diisocyanate; hydrogenated diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, and isocyanate Alicyclic diisocyanates such as porone diisocyanate and norbornene diisocyanate are preferably used, and particularly preferably, from the viewpoint of small curing shrinkage, alicyclic diisocyanate (particularly, isophorone diisocyanate, hydrogenated diphenylmethanedi Isocyanate, hydrogenated xylene diisocyanate) are used, and more preferably, from the viewpoint of excellent reactivity and versatility, hydrogenated xylene diisocyanate and isophorone diisocyanate are used.

Examples of the hydroxyl group-containing (meth)acrylate-based compound (a2) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylic. Hydroxyalkyl (meth)acrylates such as acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate; 2-hydroxyethylacryloyl phosphate, 2-(meth)acrylic Royloxyethyl-2-hydroxypropylphthalate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, dipropylene glycol (meth)acrylate, fatty acid-modified glycidyl (meth)acrylate, polyethylene glycol mono( Meth)acrylate, polypropylene glycol mono(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl(meth)acrylate, glycerindi(meth)acrylate, 2-hydroxy-3 -Acryloyl-oxypropyl methacrylate, 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 (meth)acrylate, ethylene oxide-modified dipentaerythritol penta (meth)acrylate, and the like.

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

Among these, a hydroxyl group-containing (meth)acrylate compound having one ethylenically unsaturated group is preferable from the viewpoint of excellent flexibility of the pressure-sensitive adhesive layer, and more preferably, 2-hydroxyethyl (meth)acrylate, 2- Hydroxyalkyl (meth)acryl, such as hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate It is a rate, and it is particularly preferable to use 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate from the viewpoint of excellent reactivity and versatility.

Examples of the polyol-based compound (a3) include polyether-based polyols, polyester-based polyols, polycarbonate-based polyols, polyolefin-based polyols, (meth)acrylic polyols, and polysiloxane-based polyols.

Examples of polyether-based polyols include polyether-based polyols containing alkylene structures such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polybutylene glycol, and polyhexamethylene glycol, and random polyalkylene glycols. Or a block copolymer is mentioned.

Examples of polyester-based polyols include polycondensation reaction products of polyhydric alcohols and polyhydric carboxylic acids, ring-opening polymerization products of cyclic esters (lactones), polyhydric alcohols, reaction products of polyhydric carboxylic acids and cyclic esters. Can be mentioned.

Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,4-tetramethylenediol, 1,3-tetramethylenediol, 2-methyl-1,3 -Trimethylenediol, 1,5-pentamethylenediol, neopentyl glycol, 1,6-hexamethylenediol, 3-methyl-1,5-pentamethylenediol, 2,4-diethyl-1,5-pentamethylene Diol, glycerin, trimetalolpropane, trimethylolethane, cyclohexanediol (1,4-cyclohexanediol, etc.), bisphenols (bisphenol A, etc.), sugar alcohols (xylitol, sorbitol, etc.), and the like. .

Examples of the polyhydric carboxylic acid include aliphatic dicarboxylic acids such as malonic acid, maleic acid, fumaric acid, succinic acid, glutal acid, adipic acid, suberic acid, azeric acid, sebacic acid, and dodecanedioic acid; 1 Alicyclic dicarboxylic acids such as ,4-cyclohexanedicarboxylic acid; aromatics such as terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalenedicarboxylic acid, paraphenylenedicarboxylic acid, trimellitic acid, etc. Dicarboxylic acid, etc. are mentioned.

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

Examples of the polycarbonate-based polyol include a reaction product of a polyhydric alcohol and phosgene, and a ring-opening polymer of a cyclic carbonate ester (alkylene carbonate, etc.).

Examples of the polyhydric alcohol include polyhydric alcohols exemplified in the description of the polyester polyol, and examples of the alkylene carbonate include ethylene carbonate, trimethylene carbonate, tetramethylene carbonate, and hexamethylene carbonate. I can.

In addition, the polycarbonate polyol may be a compound having a carbonate bond in the molecule and a hydroxyl group at the terminal thereof, or may have an ester bond together with a carbonate bond.

Examples of the polyolefin-based polyol include those having a homopolymer or copolymer such as ethylene, propylene, and butene as a saturated hydrocarbon skeleton, and having a hydroxyl group at the molecular terminal thereof. For example, polyisoprene-based polyol, polybutadiene-based polyol, nitrile butadiene-based polyol, styrene butadiene-based polyol, and the like can be mentioned.

The polyolefin-based polyol may be a hydrogenated polyolefin-based polyol in which all or part of the ethylenically unsaturated groups contained in the structure is hydrogenated.

Examples of the (meth)acrylic polyol include those having at least two hydroxyl groups in the molecule of the polymer or copolymer of the (meth)acrylic acid ester, and examples of such (meth)acrylic acid ester include (meth) Methyl acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylate-2-ethylhexyl, (meth) decyl acrylate, ( And (meth)acrylic acid alkyl esters such as meth)acrylic acid dodecyl and (meth)acrylic acid octadecyl.

Examples of the polysiloxane-based polyol include dimethylpolysiloxane polyol and methylphenylpolysiloxane polyol.

Among these, polyester-based polyols and polyether-based polyols are preferred, and polyester-based polyols are particularly preferred from the viewpoint of versatility.

Further, the number of hydroxyl groups contained in the polyol-based compound (a3) is preferably 2 to 5, particularly preferably 2 to 3, and more preferably 2. When the number of hydroxyl groups is too large, gelation tends to occur during the reaction.

In the present invention, the weight average molecular weight of the polyol-based compound (a3) is preferably 1,000 to 20,000, particularly preferably 2,000 to 18,000, and still more preferably 3,000 to 16,000. When such a weight average molecular weight is too small, the adhesive strength of the pressure-sensitive adhesive layer tends to decrease, and when too large, the reactivity with the polyvalent isocyanate compound (a1) tends to decrease.

In addition, the above weight average molecular weight is a weight average molecular weight in terms of standard polystyrene molecular weight, and in high performance liquid chromatography (Showa Dengo, "Shodex GPC system-11 type"), column: Shodex GPC KF-806L ( Exclusion limit molecular weight: 2×10 ⁷ , separation range: 100 to 2×10 ⁷ , number of theoretical plates: 10,000 stages/piece, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm) Is measured by

The hydroxyl value of the polyol-based compound (a3) is preferably 10 to 300 mg KOH/g, particularly preferably 15 to 150 mg KOH/g, and more preferably 20 to 120 mg KOH/g. If such a hydroxyl value is too high, the urethane (meth)acrylate-based compound (A) tends to have a low molecular weight, resulting in a decrease in adhesive strength, and if it is too low, there is a tendency that the workability decreases due to high viscosity.

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

For example, (1) a method in which the above polyvalent isocyanate compound (a1), a hydroxyl group-containing (meth)acrylate compound (a2), and a polyol compound (a3) are put into a reactor collectively or separately to react, (2) ) A method of reacting a hydroxyl group-containing (meth)acrylate-based compound (a2) to a reaction product obtained by reacting a polyol-based compound (a1) and a polyol-based compound (a3) in advance. From the viewpoint of reduction of by-products and the like, the method (2) is preferred.

Known reaction means can be used for the reaction of the polyhydric isocyanate compound (a1) and the polyol compound (a3). At this time, for example, by setting the molar ratio of the isocyanate group in the polyvalent isocyanate compound (a1) to the hydroxyl group in the polyol compound (a3) about 2n: (2n-2) (n is an integer of 2 or more), the isocyanate group remains The resulting urethane (meth)acrylate-based compound containing a terminal isocyanate group can be obtained, and after obtaining the compound, an addition reaction with a hydroxyl-containing (meth)acrylate-based compound (a2) is allowed.

Known reaction means can also be used for the addition reaction of the reaction product obtained by reacting the polyhydric isocyanate compound (a1) and the polyol compound (a3) in advance with the hydroxyl group-containing (meth)acrylate compound (a2).

The reaction molar ratio of the reaction product and the hydroxyl group-containing (meth)acrylate-based compound (a2) is, for example, two isocyanate groups of the polyvalent isocyanate-based compound (a1), and the hydroxyl group-containing (meth)acrylate-based compound (a2). In the case of one hydroxyl group, the reaction product: a hydroxyl group-containing (meth)acrylate-based compound (a2) is about 1:2, the polyvalent isocyanate-based compound (a1) has three isocyanate groups, and a hydroxyl group-containing (meth)acrylate-based compound (a2) When the compound (a2) has one hydroxyl group, the reaction product: a hydroxyl group-containing (meth)acrylate-based compound (a2) is about 1:3.

In the addition reaction of this reaction product and the hydroxyl group-containing (meth)acrylate-based compound (a2), the reaction is terminated when the content of the residual isocyanate group in the reaction system becomes 0.2% by weight or less. Compound (A) is obtained.

In the reaction of such a polyhydric isocyanate compound (a1) and a polyol compound (a3), and in the reaction of the reaction product and a hydroxyl group-containing (meth)acrylate compound (a2), a catalyst for the purpose of accelerating the reaction It is also preferable to use.

Examples of such catalysts include dibutyltin dilaurate, dibutyltin diacetate, trimethyltin hydroxide, tetra-n-butyltin, bisacetylacenatozinc, zirconium tris (acetylacetate) ethylacetate, Organometallic compounds such as zirconium tetraacetylacetate; tin octenate, zinc hexanoate, zinc octenate, zinc stearate, zirconium 2-ethylhexanoate, cobalt naphthenate, stannous chloride, stannous chloride, potassium acetate, etc. Metal salt of; Triethylamine, triethylenediamine, benzyldiethylamine, 1,4-diazabicyclo[2,2,2]octane, 1,8-diazabicyclo[5,4,0]undecene, N Amine catalysts such as ,N,N',N'-tetramethyl-1,3-butanediamine, N-methylmorpholine, and N-ethylmorpholine; Bismuth nitrate, bismuth bromide, bismuth iodide, bismuth sulfide, etc. , Organic bismuth compounds such as dibutyl bismuth dilaurate and dioctyl bismuth dilaurate, bismuth 2-ethylhexanoic acid, bismuth naphthenic acid, bismuth isodecanoic acid, bismuth neodecanoic acid, bismuth lauryl acid Bismuth catalysts such as organic acid bismuth salts such as salts, bismuth maleate, bismuth stearate, bismuth oleic acid, bismuth linoleic acid, bismuth acetate, bismuth bisneodecanoate, bismuth disalicylate, bismuth dimol acid salt, etc Among them, dibutyltin dilaurate and 1,8-diazabicyclo[5,4,0]undecene are very suitable. These can be used alone or in combination of two or more.

In addition, in the reaction of the polyol-based compound (a1) and the polyol-based compound (a3), and the reaction of the reaction product and the hydroxyl-containing (meth)acrylate-based compound (a2), if necessary, the reaction with respect to an isocyanate group Organic solvents that do not have such functional groups, 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 may also be used. .

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.

In addition, when producing a urethane (meth) acrylate compound (A) by reacting a polyvalent isocyanate compound (a1), a hydroxyl group-containing (meth) acrylate compound (a2), and a polyol compound (a3), described later A mixture of a urethane (meth)acrylate-based compound (A) and an ethylenically unsaturated monomer (B) can also be prepared by making the ethylenically unsaturated monomer (B) present in the reaction system.

For example, a urethane (meth)acrylate compound by reacting a hydroxyl group-containing (meth)acrylate compound (a2) to a reaction product obtained by reacting a polyvalent isocyanate compound (a1) and a polyol compound (a3) in advance. In the method for producing (A), when reacting the polyhydric isocyanate compound (a1) and the polyol compound (a3), an ethylenically unsaturated monomer (B) may be present in the reaction system.

The weight average molecular weight of the urethane (meth)acrylate compound (A) is 20,000 to 120,000, preferably 21,000 to 100,000, particularly preferably 22,000 to 90, 000, and more preferably 25,000 to 80,000. If such a weight average molecular weight is too low, the adhesive strength of the pressure-sensitive adhesive layer tends to decrease, and if it is too high, the viscosity of the urethane (meth)acrylate-based compound (A) tends to become too high and handling becomes difficult.

In addition, the above weight average molecular weight is a weight average molecular weight in terms of standard polystyrene molecular weight, and in high performance liquid chromatography (Showa Denko Corporation, "Shodex GPC system-11 type"), column: Shodex GPC KF-806L (Exclusion limit molecular weight: 2×10 ⁷ , separation range: 100 to 2×10 ⁷ , number of theoretical plates: 10,000 stages/piece, filler material: styrene-divinylbenzene copolymer, filler particle size: 10 μm) It is measured by using.

In addition, about the viscosity of the urethane (meth)acrylate compound (A), the viscosity at 60°C is preferably 1,000 to 1,000,000 mPa·s, particularly preferably 2,000 to 800,000 mPa·s, and more preferably Is 3,000 to 600,000 mPa·s. If such a viscosity is too high, handling tends to become difficult, and if it is too low, control of the film thickness at the time of coating tends to become difficult.

In addition, the method of measuring the viscosity follows the E-type viscometer.

(Ethylenically unsaturated monomer (B))

The active energy ray-curable pressure-sensitive adhesive composition of the present invention is an ethylenically unsaturated monomer (B) (except for the urethane (meth) acrylate compound (A)) (hereinafter, described as ``ethylenically unsaturated monomer (B)''). It also contains) as a heterocycle-containing monomer (b1) and a hydroxyl-containing monomer (b2).

Examples of the heterocycle-containing monomer (b1) include (meth)acryloylmorpholine, tetramethylpiperidinyl (meth)acrylate, pentamethylpiperidinyl (meth)acrylate, and maleimide (meth)acrylic. Heterocyclic-containing monomers having nitrogen atoms such as rate, ethylene oxide isocyanurate-modified di(meth)acrylate, ethylene oxide isocyanurate-modified tri(meth)acrylate, N-vinylpyrrolidone, and 2-vinylpyridine; Glycidyl (meth)acrylate, 3-ethyl-3-oxetanylmethyl (meth)acrylate, furfuryl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, (2-methyl-2- Ethyl-1,3-dioxolan-4-yl)methyl(meth)acrylate, cyclohexanespiro-2-(1,3-dioxolan-4-yl)methyl(meth)acrylate, γ-butylol Heterocycle-containing monomers having oxygen atoms such as lactone (meth)acrylate and trimethylolpropane (formal) (meth)acrylate; containing heterocycles having two or more heteroatoms such as oxazolidone (meth)acrylate And monomers. Among these, a heterocycle-containing monomer (b1) having one ethylenically unsaturated group is preferred from the viewpoint of excellent flexibility of the pressure-sensitive adhesive layer, and more preferably, a heterocycle containing one ethylenic unsaturated group and a nitrogen atom is contained. The monomer is preferable from the viewpoint of excellent cohesion of the pressure-sensitive adhesive layer, and (meth)acryloylmorpholine is particularly preferable.

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

When obtaining the active energy ray-curable pressure-sensitive adhesive composition of the present invention, the heterocycle-containing monomer (b1) may be contained in the synthesized urethane (meth)acrylate-based compound (A), or a urethane (meth)acrylate-based compound ( It can also be used as a diluent during the synthesis reaction of A). In order to suppress an increase in viscosity, the heterocycle-containing monomer (b1) is preferably used as a diluent during the synthesis reaction of the urethane (meth)acrylate compound (A).

When the heterocycle-containing monomer (b1) is used as a diluent during the synthesis reaction of the urethane (meth)acrylate compound (A), it is usually (A):(b1)=50:50 to 95:5 (weight ratio). , Preferably (A):(b1)=60:40 to 90:10 (weight ratio), particularly preferably (A):(b1)=70:30 to 90:10 (weight ratio).

Examples of the hydroxyl group-containing monomer (b2) include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl Hydroxyalkyl (meth)acrylates such as (meth)acrylate and 6-hydroxyhexyl (meth)acrylate, 2-hydroxyethylacryloyl phosphate, 2-(meth)acryloyloxyethyl-2- Hydroxypropylphthalate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, dipropylene glycol (meth)acrylate, fatty acid-modified glycidyl (meth)acrylate, polyethylene glycol mono (meth)acrylate, polypropylene Glycol mono(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl(meth)acrylate, glycerin mono(meth)acrylate, glycerin di(meth)acrylate, ethylene glycol diglycy Dyl ether di (meth) acrylate, diethylene glycol diglycidyl ether di (meth) acrylate, phthalic acid diglycidyl ester di (meth) acrylate, 2-hydroxy-3-acryloyloxypropyl meth Crylate, pentaerythritol di(meth)acrylate, 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 (meth) acrylate, ethylene oxide modified dipentaerythritol penta (meth) acrylate, N-methylol ( Meth)acrylamide and the like.

Among these, a hydroxyl group (meth)acrylate-based compound having one ethylenically unsaturated group is preferred from the viewpoint of excellent flexibility of the pressure-sensitive adhesive layer, and further, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth) )Hydroxyalkyl (meth)acrylates such as acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate are excellent in versatility. It is preferable from a viewpoint, and it is particularly preferable to use 4-hydroxybutyl (meth)acrylate from the viewpoint of high adhesion of the pressure-sensitive adhesive layer and low skin irritation.

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

When obtaining the active energy ray-curable pressure-sensitive adhesive composition of the present invention, the hydroxyl group-containing monomer (b2) may be contained in the synthesized urethane (meth)acrylate compound (A), or the urethane (meth)acrylate compound (A ) Can also be used as a diluent during the synthesis reaction and as a hydroxyl group-containing (meth)acrylate (a2).

In the present invention, the content ratio (weight ratio) of the heterocycle-containing monomer (b1) and the hydroxyl group-containing monomer (b2) is (b1):(b2)=25:75 to 80:20, preferably (b1):( b2)=25:75 to 75:25, particularly preferably (b1):(b2)=30:70 to 70:30, more preferably (b1):(b2)=30:70 to 60:40 to be.

If the ratio of the heterocycle-containing monomer (b1) to the hydroxyl group-containing monomer (b2) is too high, the coating film becomes hard and the adhesive strength of the pressure-sensitive adhesive layer tends to decrease, and the heterocycle-containing monomer (b1) to the hydroxyl group-containing monomer (b2) If the ratio of is too low, the adhesive strength of the pressure-sensitive adhesive layer decreases due to insufficient cohesion, and the viscosity at the time of manufacture tends to become too high, making it difficult to manufacture.

As the ethylenically unsaturated monomer (B), in addition to the heterocycle-containing monomer (b1) and the hydroxyl group-containing monomer (b2), other monomers (b3) such as a monofunctional monomer, a bifunctional monomer, and a trifunctional or higher functional monomer may also be included.

Examples of such monofunctional monomers include styrene monomers such as styrene, vinyltoluene, chlorostyrene, and α-methylstyrene, methyl (meth)acrylate, ethyl (meth)acrylate, acrylonitrile, and 2-meth. Toxoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, lauryl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, tricyclodecanyl (meth)acrylate , Dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, n-butyl (meth) acrylate, hexyl (meth) acrylate, heptyl ( Meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, dodecyl (meth) acrylate, n-stearyl (meth) acrylic Rate, benzyl (meth)acrylate, phenol ethylene oxide modified (n=2) (meth)acrylate, nonylphenol propylene oxide modified (n=2.5) (meth)acrylate, 2-(meth)acryloyloxyethyl Half (meth)acrylate, ethylcarbitol (meth)acrylate, benzyl (meth)acrylate, butoxyethyl (meth)acrylate, aryl (meth)acrylate, polyoxyethylene derivatives of phthalic acid derivatives such as acid phosphate (Meth)acrylate-based monomers such as secondary alkyl ether acrylate, vinyl acetate, and the like.

As such a bifunctional monomer, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene Glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, ethylene Oxide modified bisphenol A type di(meth)acrylate, propylene oxide modified bisphenol A type di(meth)acrylate, cyclohexanedimethanoldi(meth)acrylate, ethoxylated cyclohexanedimethanoldi(meth)acrylate, dimethyl Alldicyclopentanedi(meth)acrylate, tricyclodecanedimethanoldi(meth)acrylate, 1,6-hexanedioldi(meth)acrylate, etc. are mentioned.

Examples of such trifunctional or higher functional monomers include trimethylolpropane tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and tri(meth)acrylic. Royloxyethoxytrimethylolpropane, glycerin polyglycidyl ether poly(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, caprolactone modified pentaerythritol tetra(meth)acrylate , Ethylene oxide-modified dipentaerythritol hexa(meth)acrylate, ethylene oxide-modified pentaerythritol tetra(meth)acrylate, and ethoxylated glycerin tri(meth)acrylate.

In addition, a Michael adduct of acrylic acid or a 2-acryloyloxyethyldicarboxylic acid monoester can also be used in combination, and examples of the Michael adduct of acrylic acid include, for example, an acrylic acid dimer, a methacrylic acid dimer, an acrylic acid trimer, Methacrylic acid trimmer, acrylic acid tetramer, methacrylic acid tetramer, etc. are mentioned.

The 2-acryloyloxyethyldicarboxylic acid monoester is a carboxylic acid having a specific substituent, for example, 2-acryloyloxyethylsuccinic acid monoester, 2-methacryloyloxyethylsuccinic acid monoester Ester, 2-acryloyloxyethylphthalic acid monoester, 2-methacryloyloxyethylphthalic acid monoester, 2-acryloyloxyethylhexahydrophthalic acid monoester, 2-methacryloyloxyethylhexahydrophthalic acid mono Ester, etc. are mentioned. Moreover, other oligoester acrylates are also mentioned.

When containing other monomers (b3) in addition to the heterocycle-containing monomer (b1) and the hydroxyl group-containing monomer (b2) as the ethylenically unsaturated monomer (B), other monomers (b3) in the ethylenically unsaturated monomer (B) The ratio of) is not particularly limited, but is usually 30% by weight or less, preferably 25% by weight or less, and particularly preferably 20% by weight or less.

The content ratio (weight ratio) of the urethane (meth)acrylate-based compound (A) and the ethylenically unsaturated monomer (B) is usually (A):(B)=80:20 to 20:80, preferably ( A):(B)=75:25 to 30:70, particularly preferably (A):(B)=70:30 to 40:60, more preferably (A):(B)=65:35 It is -50:50. When there is too much ethylenically unsaturated monomer (B) for the urethane (meth)acrylate compound (A), the viscosity of the pressure-sensitive adhesive composition tends to be too low, making it difficult to paint thickly, and if too small, the viscosity of the pressure-sensitive adhesive composition is too low There is a tendency to become high and difficult to handle.

In this way, the active energy ray-curable pressure-sensitive adhesive composition of the present invention is obtained. In the present invention, it is preferable to further contain a photopolymerization initiator in the active energy ray-curable pressure-sensitive adhesive composition.

The photoinitiator is not particularly limited as long as it generates a radical by the action of light, and examples include diethoxyacetphenone, 2-hydroxy-2-methyl-1-phenyl propan-1-one, benzyldimethylketal, 4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexylphenylketone, 2-methyl-2-morpholino(4-thiomethylphenyl)propane- 1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butanone, 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanol oligomer , 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-｛4-[4-(2 Acetphenones such as -hydroxy-2-methylpropionyl)-benzyl]-phenyl}-2-methyl-propan-1-one; benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether , Benzoins such as benzoin isobutyl ether; benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenylsulfide, 3,3',4,4'-tetra (t-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, 4-benzoyl-N,N-dimethyl-N-[2-(1-oxo-2-propenyloxy)ethyl] Benzophenones such as benzene metanaminium bromide and (4-benzoylbenzyl) trimethylammonium chloride; 2-isopropyl thioxanthone, 4-isopropyl thioxanthone, 2,4-diethyl thioxanthone, 2 ,4-dichlorothioxanthone, 1-chloro-4-propoxycytoxanthone, 2-(3-dimethylamino-2-hydroxy)-3,4-dimethyl-9H-thioxanthone-9-onemeso Thioxanthones such as chloride; 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethyl-pentylphosphine oxide, bis(2 Acyl phosphone oxides, such as ,4,6-trimethylbenzoyl)-phenylphosphine oxide; etc. are mentioned. Moreover, these photoinitiators can be used individually or can use 2 or more types together.

In addition, as preparations of these photopolymerization initiators, for example, triethanolamine, triisopropanolamine, 4,4'-dimethylaminobenzophenone (Mihiraketone), 4,4'-diethylaminobenzophenone, 2-dimethylaminoethyl Benzoic acid, 4-dimethylamino ethyl benzoate, 4-dimethylamino benzoic acid (n-butoxy) ethyl, 4-dimethylamino benzoic acid isoamyl, 4-dimethylamino benzoic acid 2-ethylhexyl, 2,4-diethylthioxanesone, It is also possible to use 2,4-diisopropylthioxane and the like in combination. These preparations can also be used alone or in combination of two or more.

The content of such a photoinitiator is preferably 1 to 10 parts by weight, particularly preferably 2, based on 100 parts by weight in total of the urethane (meth)acrylate compound (A) and the ethylenically unsaturated monomer (B). It is -5 parts by weight. If such a content is too small, the curing rate tends to decrease, and even if it is too large, the curability does not improve and the economy tends to decrease.

In the active energy ray-curable pressure-sensitive adhesive composition of the present invention, in addition to the urethane (meth)acrylate-based compound (A), ethylenically unsaturated monomer (B), and photopolymerization initiator, antioxidants, flame retardants, antistatic agents, fillers, labeling agents, stabilizers, It is also possible to contain a reinforcing agent, a matting agent, and the like. Further, as a crosslinking agent, a compound having an action of causing crosslinking by heat, specifically an epoxy compound, an aziridine compound, a melamine compound, an isocyanate compound, a chelate compound, and the like can also be used.

Further, the active energy ray-curable pressure-sensitive adhesive composition of the present invention may contain a polythiol compound from the viewpoint of suppressing unreacted components and improving adhesive strength.

The polythiol compound is not particularly limited, but a compound having 2 to 6 mercapto groups in the molecule is preferable. For example, aliphatic polythiols such as alkanedithiol having 2 to 20 carbon atoms, xylenedithiol Aromatic polythiols such as, etc., polythiols obtained by substituting a halogen atom of a halohydrin adduct of alcohols with a mercapto group, polythiols consisting of a hydrogen sulfide reaction product of a polyepoxide compound, 2 to 6 hydroxyl groups in the molecule And polythiols composed of polyhydric alcohols having thioglycolic acid, β-mercaptopropionic acid, or esterified products of β-mercaptobutanoic acid, and these may be used alone or in combination of two or more. I can.

The content of the polythiol compound is preferably 0.01 to 10 parts by weight or less, and 0.1 to 5 parts by weight or less, based on 100 parts by weight of the total of the urethane (meth) acrylate compound (A) and the ethylenically unsaturated monomer (B). It is particularly preferred.

In addition, the active energy ray-curable pressure-sensitive adhesive composition of the present invention, if necessary, in order to adjust the viscosity at the time of coating, alcohols such as methanol, ethanol, propanol, n-butanol, i-butanol; acetone, methyl isobutyl ketone , Ketones such as methyl ethyl ketone and cyclohexanone; cellosolves such as ethyl cellosolve; aromatics such as toluene and xylene; glycol ethers such as propylene glycol monomethyl ether; methyl acetate, ethyl acetate, butyl acetate A dilute solvent such as acetic acid esters; diacetone alcohol or the like can also be used, but since there is a possibility that the solvent remains in the coating film or the cured component volatilizes during drying, it is preferable that the solvent is not substantially contained.

In addition, substantially no solvent refers to usually 1% by weight or less, preferably 0.5% by weight or less, and more preferably 0.1% by weight or less with respect to the entire active energy ray-curable pressure-sensitive adhesive composition.

The active energy ray-curable pressure-sensitive adhesive composition of the present invention is usually applied to a base sheet or the like, and is often provided for practical use as a pressure-sensitive adhesive sheet (an adhesive sheet is a meaning including an adhesive film and an adhesive tape when not specifically mentioned), and the like. , After application to the base sheet, it is crosslinked by irradiation with active energy rays to become a pressure-sensitive adhesive, and adhesiveness is expressed.

Examples of the base sheet include polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyolefin resins such as polyethylene, polypropylene and ethylene-propylene copolymers, polycarbonate resins, polyurethane resins, and acrylic resins. Resin sheets such as resin, polystyrene resin, ethylene-vinyl acetate copolymer, polyvinyl chloride, polybutene, polybutadiene, polymethylpentene, acrylonitrile butadiene styrene copolymer (ABS), and glass plates. For various substrate sheets, those subjected to surface treatment such as an anchor layer, corona treatment, or plasma treatment may also be used.

The coating method of the active energy ray-curable pressure-sensitive adhesive composition is not particularly limited, and examples thereof include a wet coating method such as spray, shower, dipping, roll, spin, screen printing, inkjet printing, and dispenser.

In the case of containing a solvent, drying is performed after application, but drying conditions may be set to a drying temperature and drying time sufficient to volatilize the solvent, and the drying temperature is usually 40 to 100°C, particularly 50 to 90°C. desirable.

The drying time may be any time in which the solvent in the coating film can be completely volatilized during drying, but it is preferably 1 to 60 minutes in consideration of production appropriateness.

After the active energy ray-curable pressure-sensitive adhesive composition of the present invention is applied to a base sheet and dried, it is cured (crosslinked) by irradiating with an active energy ray to obtain a pressure-sensitive adhesive and an adhesive sheet.

Further, until the pressure-sensitive adhesive sheet of the present invention is attached to the adherend (member), for the purpose of protecting the pressure-sensitive adhesive from contamination, a separator can be laminated on the surface of the pressure-sensitive adhesive. As the separator, a resin sheet exemplified above, or a material obtained by a release treatment of a substrate such as paper, cloth, or nonwoven fabric can be used.

In installing the pressure-sensitive adhesive composition on the base sheet, usually, as a solution of the active energy ray-curable pressure-sensitive adhesive composition, the viscosity is adjusted to a suitable viscosity for application with a solvent as needed, and then applied to the base sheet and dried. As a method of application, a direct coating method in which an active energy ray-curable pressure-sensitive adhesive composition in the form of a solution is directly applied to a substrate sheet, or a transfer coating method in which an active energy-ray-curable pressure-sensitive adhesive composition in a solution form is applied to the separator and then pasted onto the substrate sheet. Can be lifted.

In the direct coating method, a method of applying an active energy ray-curable pressure-sensitive adhesive composition to a base sheet and drying by heating, irradiating an active energy ray, and then attaching a separator, or applying an active energy-ray-curable pressure-sensitive adhesive composition to the base sheet and heating it. After drying, after attaching a separator, a method of irradiating an active energy ray, etc. are mentioned. Coating is performed by a method such as roll coating, die coating, gravure coating, comma coating, screen printing, and printing coating with a dispenser.

On the other hand, in the transfer coating method, a method of applying an active energy ray-curable pressure-sensitive adhesive composition to a separator, heat-drying, and then irradiating an active energy ray, and then attaching a base sheet, or applying an active energy-ray-curable pressure-sensitive adhesive composition to the separator. After heating and drying, after attaching the base sheet, a method of irradiating an active energy ray, etc. are mentioned. About the coating method, the same method as direct coating can be used.

As the above-mentioned active energy rays, rays such as far ultraviolet rays, ultraviolet rays, near ultraviolet rays, infrared rays, electromagnetic waves such as X-rays and γ rays, electron rays, phloton rays, neutron rays, etc. can be used. It is advantageous to cure by UV irradiation because of its ease of use and price. In addition, when performing electron beam irradiation, curing can be performed even without using a photoinitiator.

As a method of curing by ultraviolet irradiation, a high-pressure mercury lamp emitting light in a wavelength range of 150 to 450 nm, 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, etc. are used. You can irradiate about 30~3000mJ/㎠.

After UV irradiation, heating may be performed as necessary to achieve complete curing.

Further, the thickness of the pressure-sensitive adhesive layer formed on the base sheet after irradiation with active energy rays is appropriately set depending on the application, but is usually 5 to 300 µm, and preferably 10 to 250 µm. If the thickness of the pressure-sensitive adhesive layer is too thin, the adhesive properties tend to be difficult to stabilize, and if the thickness of the pressure-sensitive adhesive layer is too thick, there is a tendency that adhesion residues tend to occur.

(Example)

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless the gist of the present invention is exceeded. In addition, in Examples, "part" and "%" mean a weight basis.

As follows, urethane (meth)acrylate compounds (A-1) to (A-7) were prepared as urethane (meth)acrylate compounds (A).

<Production of urethane (meth)acrylate compound (A-1)>

In a 4-neck flask equipped with a thermometer, stirrer, water cooling condenser, and nitrogen gas inlet, isophorone diisocyanate (a1) 12.2 g (0.055 mol), bifunctional polyester polyol (a3-1) (weight average molecular weight (Mw) =7,000) 85.2 g (0.044 mol), dibutyltin dilaurate 0.02 g was added as a reaction catalyst, and after reacting at 60° C. for 8 hours, 2.6 g (0.022 mol) of 2-hydroxyethyl acrylate (a2), As a polymerization inhibitor, 0.04 g of 2,6-di-tert-butylcresol was added and reacted at 60°C for 6 hours. When the residual isocyanate group became 0.3%, the reaction was terminated, and a urethane (meth)acrylate-based compound (A-1) (Mw; 34,000) was obtained.

<Production of urethane (meth)acrylate compound (A-2)>

In a 4-neck flask equipped with a thermometer, stirrer, water cooling condenser, and nitrogen gas inlet, isophorone diisocyanate (a1) 8.5 g (0.038 mol), bifunctional polyester polyol (a3-1) (Mw=7,000) 53.9 g (0.027 mol), bifunctional polyester polyol (a3-2) (Mw=12,000) 15.7 g (0.004 mol), acryloylmorpholine (b1-1) 20.0 g, dibutyltin dilaurate 0.02 as a reaction catalyst g, 0.04 g of 2,6-di-tert-butylcresol was added as a polymerization inhibitor, reacted at 60° C. for 8 hours, and 1.8 g (0.015 mol) of 2-hydroxyethyl acrylate (a2) was added to 60° C. Reacted for 6 hours. When the residual isocyanate group reached 0.3%, the reaction was terminated, and a mixture of a urethane (meth)acrylate-based compound (A-2) (Mw; 35,000) and acryloylmorpholine (b1-1) (urethane (meth)) The acrylate compound concentration: 80%) was obtained.

<Production of urethane (meth)acrylate compound (A-3)>

In a 4-neck flask equipped with a thermometer, stirrer, water cooling condenser, and nitrogen gas inlet, isophorone diisocyanate (a1) 7.8 g (0.035 mol), bifunctional polyester polyol (a3-1) (Mw=7,000) 42.0 g (0.021 mol), bifunctional polyester polyol (a3-2) (Mw=12,000) 28.6 g (0.007 mol), acryloylmorpholine (b1-1) 20.0 g, dibutyltin dilaurate 0.02 as a reaction catalyst g was added and reacted at 60° C. for 8 hours, and then 1.7 g (0.015 mol) of 2-hydroxyethyl acrylate (a2) and 0.04 g of 2,6-di-tert-butylcresol as polymerization inhibitor were added to 60° C. Reacted for 6 hours. When the residual isocyanate group reached 0.3%, the reaction was terminated, and a mixture of a urethane (meth)acrylate compound (A-3) (Mw; 36,000) and acryloylmorpholine (b1-1) (urethane (meth)) The acrylate compound concentration: 80%) was obtained.

<Production of urethane (meth)acrylate compound (A-4)>

In a 4-neck flask equipped with a thermometer, stirrer, water cooling condenser, and nitrogen gas inlet, isophorone diisocyanate (a1) 26.4 g (0.119 mol), bifunctional polyester polyol (a3-3) (Mw=1, 300) 51.4 g (0.109 mol), acryloylmorpholine (b1-1) 20.0 g, dibutyltin dilaurate 0.02 g as a reaction catalyst, reacted at 60° C. for 8 hours, and then 2-hydroxyethyl acrylate (a2) 2.2 g (0.019 mol) and 0.04 g of 2,6-di-tert-butylcresol were added as a polymerization inhibitor and reacted at 60° C. for 6 hours. When the residual isocyanate group reached 0.3%, the reaction was terminated, and a mixture of a urethane (meth)acrylate-based compound (A-4) (Mw; 36,000) and acryloylmorpholine (b1-1) (urethane (meth)) The acrylate compound concentration: 80%) was obtained.

<Production of urethane (meth)acrylate compound (A-5)>

In a 4-neck flask equipped with a thermometer, stirrer, water cooling condenser, and nitrogen gas inlet, isophorone diisocyanate (a1) 11.4 g (0.051 mol), bifunctional polyether polyol (a3-4) (Mw=7,000) 86.5 g (0.044 mol), 0.02 g of dibutyltin dilaurate was added as a reaction catalyst, and after reacting at 60° C. for 8 hours, 2.2 g (0.019 mol) of 2-hydroxyethyl acrylate (a2), 2 as a polymerization inhibitor 0.04 g of ,6-di-tert-butyl cresol was added and reacted at 60°C for 6 hours. When the residual isocyanate group became 0.3%, the reaction was terminated, and a urethane (meth)acrylate-based compound (A-5) (Mw; 38,000) was obtained.

<Production of urethane (meth)acrylate compound (A-6)>

In a 4-neck flask equipped with a thermometer, stirrer, water cooling condenser, and nitrogen gas inlet, isophorone diisocyanate (a1) 14.0 g (0.063 mol), bifunctional polyester polyol (a3) (Mw=7,000) 81.0 g (0.042) Mol), 0.02 g of dibutyltin dilaurate was added as a reaction catalyst, and after reacting at 60°C for 4 hours, 5.0 g (0.043 mol) of 2-hydroxyethyl acrylate (a2), 2,6 as a polymerization inhibitor -Di-tert-butylcresol 0.04g was added and reacted at 60°C for 3 hours. When the residual isocyanate group became 0.3%, the reaction was terminated, and a urethane (meth)acrylate-based compound (A-6) (Mw; 18,000) was obtained.

<Production of urethane (meth)acrylate compound (A-7)>

In a 4-neck flask equipped with a thermometer, stirrer, water cooling condenser, and nitrogen gas inlet, isophorone diisocyanate (a1) 16.4 g (0.074 mol), bifunctional polyether polyol (a3) (Mw=7,000) 72.7 g (0.037) Mol), 0.02 g of dibutyltin dilaurate was added as a reaction catalyst, and after reacting at 60°C for 4 hours, 10.9 g (0.094 mol) of 2-hydroxyethyl acrylate (a2), 2,6 as a polymerization inhibitor -Di-tert-butylcresol 0.04g was added and reacted at 60°C for 3 hours. When the residual isocyanate group became 0.3%, the reaction was terminated, and a urethane (meth)acrylate-based compound (A-7) (Mw; 13,000) was obtained.

<Ethylenically unsaturated monomer (B)>

The following were prepared as ethylenically unsaturated monomers (B).

(b1-1): Acryloylmorpholine

(b2-1): 4-hydroxybutyl acrylate

(b3-1): Normal butyl acrylate

[Example 1]

The urethane (meth)acrylate resin (A-1) prepared above 55.2 parts, ethylenically unsaturated monomer (b1-1) 13.8 parts, (b2-1) 31 parts (content ratio (weight ratio) is (b1-1) ):(B2-1)=31:69), 4-hydroxy-cyclohexyl-phenyl-ketone (manufactured by BASF Japan; "Irgacure 184") as a photoinitiator, 4 parts uniformly mixed, and an active energy ray-curable adhesive The composition was obtained.

[Example 2]

In Example 1, the ethylenically unsaturated monomer (b1-1) 22.4 parts, (b2-1) 22.4 parts (the content ratio (weight ratio) was changed to (b1-1): (b2-1) = 50: 50) Except for the thing, it carried out similarly, and obtained the active energy ray-curable adhesive composition.

[Example 3]

In Example 1, 31.4 parts of ethylenically unsaturated monomers (b1-1), (b2-1) 13.4 parts (content ratio (weight ratio) was changed to (b1-1):(b2-1)=70:30) Except for the thing, it carried out similarly, and obtained the active energy ray-curable adhesive composition.

[Example 4]

69 parts of a mixture of the urethane (meth)acrylate-based resin (A-2) and acryloylmorpholine (b1-1) prepared above (urethane (meth)acrylate-based compound (A-2) 55.2 parts, acrylic Roylmorpholine (b1-1) 13.8 parts), ethylenically unsaturated monomer (b2-1) 31 parts, 1-hydroxy-cyclohexyl-phenyl-ketone as a photoinitiator (manufactured by BASF Japan; "Irgacure 184") 4 parts were mixed uniformly to obtain an active energy ray-curable pressure-sensitive adhesive composition (the content ratio (weight ratio) of the ethylenically unsaturated monomer was (b1-1):(b2-1)=31:69).

[Example 5]

69 parts of a mixture of the urethane (meth)acrylate-based resin (A-3) and acryloylmorpholine (b1-1) prepared above (urethane (meth)acrylate-based compound (A-3) 55.2 parts, acrylic Roylmorpholine (b1-1) 13.8 parts), ethylenically unsaturated monomer (b2-1) 31 parts, 1-hydroxy-cyclohexyl-phenyl-ketone as a photoinitiator (manufactured by BASF Japan; "Irgacure 184") 4 parts were mixed uniformly to obtain an active energy ray-curable pressure-sensitive adhesive composition (the content ratio (weight ratio) of the ethylenically unsaturated monomer was (b1-1):(b2-1)=31:69).

[Example 6]

69 parts of a mixture of the urethane (meth)acrylate-based resin (A-4) and acryloylmorpholine (b1-1) prepared above (urethane (meth)acrylate-based compound (A-4) 55.2 parts, acrylic Roylmorpholine (b1-1) 13.8 parts), ethylenically unsaturated monomer (b2-1) 31 parts, 1-hydroxy-cyclohexyl-phenyl-ketone as a photoinitiator (manufactured by BASF Japan; "Irgacure 184") 4 parts were mixed uniformly, and the active energy ray-curable adhesive composition was obtained (the content ratio (weight ratio) of an ethylenically unsaturated monomer is (b1-1):(b2-1)=31:69).

[Example 7]

In Example 1, an active energy ray-curable pressure-sensitive adhesive composition was obtained in the same manner except that the urethane (meth)acrylate-based resin (A-1) was changed to a urethane (meth)acrylate-based resin (A-5).

[Comparative Example 1]

In Example 1, the ethylenically unsaturated monomer (b1-1) 2.2 parts, (b2-1) 42.6 parts (content ratio (weight ratio) was changed to (b1-1): (b2-1) = 5:95) Except for the thing, it carried out similarly, and obtained the active energy ray-curable adhesive composition.

[Comparative Example 2]

In Example 1, the ethylenically unsaturated monomer (b1-1) 4.5 parts, (b2-1) 40.3 parts (content ratio (weight ratio) was changed to (b1-1): (b2-1) = 10: 90) Except for the thing, it carried out similarly, and obtained the active energy ray-curable adhesive composition.

[Comparative Example 3]

In Example 1, 9 parts of ethylenically unsaturated monomers (b1-1), (b2-1) 35.9 parts (content ratio (weight ratio) was changed to (b1-1):(b2-1)=20:80) Except for the thing, it carried out similarly, and obtained the active energy ray-curable adhesive composition.

[Comparative Example 4]

In Example 1, 40.3 parts of ethylenically unsaturated monomers (b1-1) and 4.5 parts of (b2-1) (the content ratio (weight ratio) was changed to (b1-1):(b2-1)=90:10). Except for the thing, it carried out similarly, and obtained the active energy ray-curable adhesive composition.

[Comparative Example 5]

In Example 1, an active energy ray-curable pressure-sensitive adhesive composition was obtained in the same manner except that the urethane (meth)acrylate-based resin (A-1) was changed to a urethane (meth)acrylate-based resin (A-6).

[Comparative Example 6]

In Example 1, an active energy ray-curable pressure-sensitive adhesive composition was obtained in the same manner except that the urethane (meth)acrylate-based resin (A-1) was changed to a urethane (meth)acrylate-based resin (A-7).

[Comparative Example 7]

In Example 1, an active energy ray-curable pressure-sensitive adhesive composition was obtained in the same manner except that the ethylenically unsaturated monomer (b2-1) was changed to the ethylenically unsaturated monomer (b3-1).

<Preparation of adhesive sheet for measuring adhesive force>

The active energy ray-curable pressure-sensitive adhesive compositions obtained in Examples 1 to 7 and Comparative Examples 1 to 7 were applied to a polyethylene terephthalate (PET) film (thickness of 125 μm) with reverse adhesion treatment so that the film thickness after curing became 175 μm. Apply using an applicator, and use 80W/cm (high pressure mercury lamp) x 18cmH x 2.04m/min x 3Pass (cumulative 2,400 mJ/cm2) with a tabletop UV irradiation device (manufactured by Iwasaki Denki, "Conveyor-type desk irradiation device") ) Under the conditions of UV irradiation and curing to obtain a pressure-sensitive adhesive sheet for measuring adhesion.

<Test method>

The obtained adhesive sheet for measuring adhesive strength was cut into 25 mm×100 mm, and then pressed against a glass plate as an adherend by reciprocating twice using a 2 kg rubber roller in an atmosphere of 23° C. and 50% relative humidity to prepare a test piece. After allowing this test piece to stand for 30 minutes in the same atmosphere, a 180 degree peel test was performed at a peel rate of 0.3 m/min, and initial adhesive strength (N/25 mm) was measured and evaluated according to the following criteria.

(Evaluation standard)

○···10N/25mm or more

×...less than 10N/25mm

<Preparation of pressure-sensitive adhesive sheet for heat resistance test>

The active energy ray-curable pressure-sensitive adhesive composition obtained in Examples 1 to 7 and Comparative Examples 1 to 7 was applied to an anti-adhesion polyethylene terephthalate (PET) film (thickness 125 μm) so that the film thickness after curing became 175 μm. And laminated with a release polyethylene terephthalate film (thickness 50 μm), 80 W/cm (high-pressure mercury lamp)×18 cmH×2.04 with a tabletop UV irradiation device (manufactured by Iwasaki Denki, “Conveyor-type tabletop irradiation device”) A pressure-sensitive adhesive sheet for a moisture and heat resistance test was obtained by irradiating and curing UV rays under conditions of m/min×3 Pass (integrated 2,400 mJ/cm 2 ).

<Test method>

After cutting the obtained pressure-sensitive adhesive sheet for a moisture and heat resistance test into 25 mm x 40 mm, it was pressed onto a glass plate as an adherend to prepare a test piece.

The obtained test piece was put in an environment of 80°C and 90%RH for 100 hours, and b* immediately after the end of the test was measured with a color difference meter to evaluate the moisture and heat resistance (transparency of the adhesive layer). The evaluation criteria are as follows.

(Evaluation standard)

○...3 or less

Greater than ×...3

<Preparation of samples for Shoa E measurement>

The active energy ray-curable pressure-sensitive adhesive composition obtained in Examples 1 to 7 and Comparative Examples 1 to 7 was poured into a container made of polyethylene, and was 80 W/ By irradiating and curing UV rays under conditions of cm (high pressure mercury lamp) x 18 cmH x 2.04 m/min x 5 Pass (integrated 4,000 mJ/cm 2 ), a sample for Shoa E measurement having a thickness of about 8 mm was obtained.

<Test method>

A pressure-sensitive adhesive layer formed by curing the active energy ray-curable pressure-sensitive adhesive composition by pressing the pressing surface of the Asuka rubber hardness tester C type (manufactured by Kobunshi Keiki Co., Ltd.) on the surface of the obtained Shoa E measurement sample and measuring the value after 15 seconds Evaluated its flexibility.

(Evaluation standard)

○...70 or less

△... greater than 70 and less than 90

×...greater than 90

Table 1 summarizes the content of the urethane (meth)acrylate resin (A) in Examples 1 to 7 and Comparative Examples 1 to 7, and its weight average molecular weight (Mw), and ethylenically unsaturated monomer (B). , The above evaluation results are put together in Table 2. In addition, "-" in a table indicates that a component is not contained.

From the above evaluation results, it can be seen that the pressure-sensitive adhesive sheets of Examples 1 to 7 according to the present invention are excellent in balance between adhesive strength and heat-and-moisture resistance, and that the pressure-sensitive adhesive layers obtained from Examples 1 to 7 have excellent flexibility.

On the other hand, in Comparative Examples 1 to 4 in which the content ratio of the heterocycle-containing monomer (b1) and the hydroxyl group-containing monomer (b2) is outside the specified range of the present invention, it can be seen that the moisture and heat resistance is good, but the adhesive strength is insufficient. In addition, in Comparative Example 4, it is also understood that the obtained pressure-sensitive adhesive layer is inferior in flexibility.

In addition, in Comparative Examples 5 and 6 using a urethane (meth)acrylate-based compound whose weight average molecular weight is less than the lower limit of the present invention, the moisture and heat resistance is good, but Comparative Example 5 has insufficient adhesive strength, and Comparative Example 6 It can be seen that the adhesive force is too low to be measured. In addition, it can be seen that the pressure-sensitive adhesive layer obtained in Comparative Example 6 is inferior in flexibility.

In addition, in Comparative Example 7, in which another ethylenically unsaturated monomer (b3-1) was used in place of the hydroxyl group-containing monomer (b2), it was found that both the adhesive strength and the moist heat resistance were insufficient.

Since the pressure-sensitive adhesive formed by curing the active energy ray-curable pressure-sensitive adhesive composition of the present invention is excellent in a balance between adhesive strength and moisture-heat resistance, it is also used as a pressure-sensitive adhesive in an electronic component fixing sheet (tape) or an electronic component label sheet (tape). It is useful as an adhesive for sticking in a display body or a touch sensor. For example, bonding of optical display panel and touch panel, bonding of optical display panel and protection panel, bonding of touch panel and protection panel, bonding of optical display panel and optical display panel, bonding of optical display panel and parallax barrier It can be used as a pressure-sensitive adhesive for attaching with.

In addition, since the pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive of the present invention is excellent also in flexibility, it is excellent in the ability to follow the step difference between members. Therefore, such a pressure-sensitive adhesive layer can be suitably used for attaching an optical member having a step difference by, for example, formation of an ITO transparent electrode or printing, and also for a touch panel comprising these optical members. It can also be used very suitably.

Further, the pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed by curing the active energy ray-curable pressure-sensitive adhesive composition of the present invention can be used in various fields in addition to the electronic components and optical members described above.

Although more specific forms of the present invention have been described with reference to the above examples, the above examples are only mere illustrations and are not intended to be interpreted as limiting. It is clear that various modifications and corrections apparent to those skilled in the art are within the scope of the present invention.

[Related application]

This application enjoys the benefit of priority based on the Japanese patent application (Japanese Patent Application No. 2014-149296) for which it applied on July 22, 2014, and all these content are taken in here by reference.

Claims (7)

Polyvalent isocyanate compound (a1), a hydroxyl group-containing (meth)acrylate compound (a2), and a polyol compound (a3) are reacted to form a urethane (meth)acrylate compound having a weight average molecular weight of 20,000 to 120,000 ( A), and
It is an active energy ray-curable pressure-sensitive adhesive composition containing an ethylenically unsaturated monomer (B) (except for a urethane (meth) acrylate-based compound (A)),
The content ratio (weight ratio) of the urethane (meth)acrylate-based compound (A) and the ethylenically unsaturated monomer (B) is (A):(B)=80:20 to 20:80,
The ethylenically unsaturated monomer (B) contains a heterocycle-containing monomer (b1) and a hydroxyl group-containing monomer (b2), and the content ratio (weight ratio) of the heterocycle-containing monomer (b1) and a hydroxyl group-containing monomer (b2) is (b1) :(B2)=25:75-80:20, The active energy ray-curable adhesive composition characterized by the above-mentioned. The method according to claim 1,
An active energy ray-curable pressure-sensitive adhesive composition, wherein the polyvalent isocyanate compound (a1) is an alicyclic polyisocyanate. The method according to claim 1 or 2,
An active energy ray-curable pressure-sensitive adhesive composition, characterized in that the number of unsaturated groups in the hydroxyl-containing (meth)acrylate-based compound (a2) is one. The method according to claim 1 or 2,
The polyol-based compound (a3) is an active energy ray-curable pressure-sensitive adhesive composition, characterized in that it is a polyether-based polyol or a polyester-based polyol. delete A pressure-sensitive adhesive comprising curing the active energy ray-curable pressure-sensitive adhesive composition according to claim 1 or 2. An adhesive sheet having an adhesive layer formed by curing the active energy ray-curable adhesive composition according to claim 1 or 2.