JP2020105277A - Adhesive and laminate - Google Patents

Abstract

To provide an adhesive which can cure sufficiently even with a small amount of irradiation and form a laminate having excellent initial adhesive strength as well as adhesive strength at a deformed region after high-temperature storage and low-temperature storage.SOLUTION: Provided is an adhesive which comprises a (meth)acrylate oligomer (A), a mono(meth)acrylate (B) containing an alicyclic ring, a mono(meth)acrylate (C) having a hydroxyl group and no amide group, and a (meth)acrylate (D) having a hydroxyl group and an amide group and may comprise a radically polymerizable component (E) other than the above (A) to (D), where, among a total of 100 mass% of the above (A) to (E), monomers containing a hydroxyl group account for 40 to 80 mass%.SELECTED DRAWING: None

Description

The present invention relates to adhesives and laminates.

A display such as a liquid crystal display or an organic EL display is used as a laminated body in which optical members such as an antireflection film, a retardation film, a polarizing plate, a liquid crystal cell (or an organic EL layer), and a touch panel are attached with an adhesive or an adhesive. Has been done.

In these optical applications such as display devices such as displays, the active energy ray-polymerizable adhesive has a high polymerization rate, and since it can generally be used without a solvent, it has excellent workability, and further the energy required during polymerization is extremely high. It is widely used because it has excellent properties such as low. As the active energy ray-polymerizable adhesive, a radical polymerizable active energy ray-polymerizable adhesive and a cationically polymerizable active energy ray-polymerizable adhesive are generally known.

In addition to being used as TVs and monitors, displays are widely used in mobile terminals such as smartphones and tablet terminals, and in-vehicle applications such as car navigation systems by providing a transparent electrode layer, etc. on the surface and having a touch input function. It is used.
In a smartphone or the like, a so-called curved display is used in which the display is extended to the thickness portion of the outer periphery of the smartphone in order to expand the display area in a limited size. In addition, smartphones are increasingly used in automobiles as car navigation utilizing apps by taking advantage of their high functionality.

As an adhesive used for a display device, an active energy ray-curable adhesive containing isocyanuric acid ethylene oxide-modified polyfunctional acrylate, benzyl metalylate, 2-hydroxyethyl methacrylate and the like (Patent Document 1) is disclosed.

Patent Document 2 discloses an active energy ray-curable adhesive containing a polyfunctional urethane acrylate, orthophenylphenol acrylate, hydroxybutyl acrylate, and hydroxyethyl methacrylate.

Patent Document 3 discloses an active energy ray-curable adhesive containing an acrylate having a heterocycle, an acrylate having a ring other than the heterocycle, and an acrylate having a hydroxyl group.

International Publication No. 2011/145524 International Publication No. 2006/118078 JP, 2017-137395, A

Typical displays for in-vehicle use are directly affected by temperature changes in winter and summer. However, the adhesives used for laminating each optical member and each optical member constituting the display device have different dimensional change rates due to temperature changes, so that after bonding, floating or peeling may occur. .. In the case of a curved display, the stress due to the difference in the dimensional change rate concentrates on the thickness portion of the outer periphery of the display, which is the deformed portion, so that the deformed portion is likely to be lifted or peeled. Further, when an active energy ray-polymerizable adhesive is applied to a substrate at a high speed in order to improve the productivity of the display, there is a problem that the irradiation amount of the active energy ray is insufficient and the adhesive strength is insufficient. If an attempt is made to increase the polymerization rate by using an adhesive containing more polyfunctional monomers and to sufficiently cure even with a small irradiation dose, the stress due to curing shrinkage will increase and the optical members will float between the deformed parts. Peeling may occur.

It is an object of the present invention to provide an adhesive which can be sufficiently cured even at a low irradiation dose and can form a laminate having not only initial adhesive strength but also excellent adhesive strength after high temperature storage and low temperature storage at a deformed portion.

The present inventors have completed the present invention as a result of intensive studies to solve the above problems.
That is, the present invention is an adhesive containing a (meth)acrylate oligomer (A) having a weight average molecular weight of 1000 or more and a (meth)acrylate monomer having a weight average molecular weight of less than 1000, wherein the (meth)acrylate monomer is , Mono(meth)acrylate (B) having an alicyclic structure, mono(meth)acrylate (C) having a hydroxyl group and not having an amide group, (meth)acrylate monomer (D) having a hydroxyl group and having an amide group And an adhesive which further comprises a radically polymerizable component (E) other than the above (A) to (D),
The present invention relates to an adhesive containing 40 to 80 mass% of a monomer having a hydroxyl group in the total 100 mass% of (A) to (E).

The (meth)acrylate oligomer (A) is preferably a polyurethane (meth)acrylate oligomer (A1), and the polyurethane (meth)acrylate oligomer (A1) is a polyurethane (meth)acrylate having a polyether skeleton. It is preferably an oligomer (A1-1).

Further, in the present invention, it is preferable that the (meth)acrylate monomer (D) having a hydroxyl group and an amide group is contained in an amount of 5 to 30% by mass in a total of 100% by mass of (A) to (E). ..
Further, in the present invention, it is preferable that the (meth)acrylate oligomer (A) is contained in an amount of 1 to 30% by mass based on 100% by mass of the total of (A) to (E).

The present invention also relates to an adhesive further containing a photoinitiator.

Furthermore, the present invention relates to a laminate including a first base material, a resin layer that is a cured product of the adhesive of the present invention, and a second base material.

According to the present invention, it is possible to provide an adhesive which can be sufficiently cured even with a low irradiation dose and can exhibit an excellent adhesive force at a deformed portion in a wide temperature range from high temperature to low temperature.

Hereinafter, embodiments of the present invention will be described.
<Adhesive>
First, terms used in this specification will be described. The term “active energy ray” means an energy ray in a broad sense including an ultraviolet ray, a visible ray, an infrared ray, an electron beam (EB), and a radiation, which can provide energy necessary for activation for causing a chemical reaction. The active energy ray-curable adhesive of the present invention undergoes a polymerization reaction upon irradiation with the active energy ray to form a cured product such as an adhesive layer.
Further, “(meth)acryloyl” includes “acryloyl and methacryloyl”. “(Meth)acrylic acid” includes “acrylic acid and methacrylic acid”. “(Meth)acrylate” includes “acrylate and methacrylate”. “(Meth)acryloyloxy” includes “acryloyloxy and methacryloyloxy”. “(Meth)allyl” includes “allyl and methallyl”. "Monomer" is "monomer containing ethylenically unsaturated bond".
The radically polymerizable monomer is, for example, a monomer having a radically polymerizable functional group such as a vinyl group or an acryloyl group.
Polyfunctional means that the number of functional groups of the ethylenically unsaturated group is 2 or more in one molecule, and bifunctional or trifunctional means that the number of functional groups of the ethylenically unsaturated group is 2 in one molecule, It also indicates that the number is three.

As described above, the adhesive of the present specification is an adhesive containing a (meth)acrylate oligomer (A) having a weight average molecular weight of 1000 or more and a (meth)acrylate monomer having a weight average molecular weight of less than 1000, wherein The (meth)acrylate monomer includes a mono(meth)acrylate (B) having an alicyclic structure, a mono(meth)acrylate (C) having a hydroxyl group and not an amide group, and a amide group having a hydroxyl group (meth). ) An adhesive which contains an acrylate monomer (D) and can further contain a radical polymerizable component (E) other than the above (A) to (D), in a total of 100% by mass of the above (A) to (E). And 40 to 80% by mass of a monomer having a hydroxyl group.

The adhesive of the present specification is preferably cured by active energy rays and used for forming an adhesive layer for bonding the first base material and the second base material together. Further, it is preferable that at least one of the base materials is a base material having a transparent conductive layer.

<(Meth)acrylate oligomer (A)>
The (meth)acrylate oligomer (A) has a weight average molecular weight of 1,000 or more, preferably 100,000 or less, and more preferably 1500 to 50,000. The (meth)acrylate oligomer (A) preferably has an average of two or more (meth)acryloyl groups per molecule.
Examples of the (meth)acrylate oligomer (A) include a polyurethane (meth)acrylate oligomer (A1), a polyester (meth)acrylate oligomer (A2), and an epoxy (meth)acrylate oligomer (A3). By using the (meth)acrylate oligomer (A), it is possible to obtain an active energy ray-polymerizable adhesive having excellent room temperature adhesive strength and high temperature suitability.
The weight average molecular weight in the present specification is a value measured by gel permeation chromatography (GPC) using polystyrene having a known weight average molecular weight as a standard substance.

The (meth)acrylate oligomer (A) is selected from the group consisting of a polyurethane (meth)acrylate oligomer (A1), a polyester (meth)acrylate oligomer (A2), and an epoxy (meth)acrylate oligomer (A3). It is preferably at least one species.

The polyurethane-based (meth)acrylate oligomer (A1) is a compound having a urethane bond and a radically polymerizable functional group. The polyurethane-based (meth)acrylate oligomer (A1) is, for example, a compound having an isocyanate group at the terminal obtained by reacting a compound having two or more isocyanate groups with a compound having a hydroxyl group, and having a (meth)acryloyl group having a hydroxyl group. It can be obtained by reacting a group. Alternatively, it can be synthesized by reacting a compound having a hydroxyl group with a compound having an isocyanate group and a (meth)acrylate group.
The polyurethane (meth)acrylate oligomer (A1) includes those having a polyether skeleton (A1-1), those having a polyester skeleton (A1-2), etc., and has an initial adhesive strength, high temperature suitability, and adhesive aging. A polyurethane-based (meth)acrylate (A1-1) having a polyether skeleton is preferable in terms of excellent stability. By using a compound having a polyether skeleton or a polyester skeleton as the compound having a hydroxyl group, a compound having a polyether skeleton (A1-1) or a compound having a polyester skeleton (A1-2) can be obtained.

Examples of the compound having two or more isocyanate groups include aromatic isocyanates such as 4,4′-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, and 1,4-phenylene bismethylene diisocyanate; 3-isocyanate methyl-3 Aliphatic isocyanates such as 5,5,5-trimethylcyclohexyl isocyanate and hexamethylene diisocyanate are exemplified.

The polyurethane (meth)acrylate oligomer (A1) is, for example, an aromatic polyurethane oligomer such as EBECRYL210, EBECRYL220 (all manufactured by Daicel Ornex Co., Ltd.), CN9782, CN9783 (all manufactured by SARTOMER); Aliphatic polyurethane oligomers such as 3000B, Shikotsu 3300B (above, manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), EBECRYL230, EBECRYL270, EBECRYL8402, EBECRYL8701 (above manufactured by Daicel Ornex) are mentioned.

The polyester (meth)acrylate oligomer (A2) is a compound having an ester bond and a radically polymerizable functional group. The compound (A2) is obtained by, for example, esterifying a hydroxyl group of a polyester synthesized by polycondensing a polybasic acid and a polyhydric alcohol, and a (meth)acrylate having a carboxyl group (for example, (meth)acrylic acid). It can be synthesized by reaction.

The polybasic acid is an aliphatic polybasic acid such as oxalic acid, malonic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, suberic acid, maleic acid, fumaric acid, itaconic acid, succinic anhydride, and maleic anhydride. Acids; examples thereof include alicyclic compounds such as dimer acid and cyclohexanedicarboxylic acid, and aromatic compounds such as isophthalic acid, terephthalic acid and biphenyldicarboxylic acid.

Polyhydric alcohols include, for example, polyethylene glycol, propylene glycol, etc., having a number average molecular weight (Mn) of 50 to 500, a polyol having a number average molecular weight (Mn) of 500 to 30,000, and trimethylolpropane, glycerin, pentaerythritol. Etc.

The polyester-based (meth)acrylate oligomer (A2) is an aromatic polyester oligomer such as CN296, CN2203, CN2259, CN2261 (above, manufactured by SARTOMER); CN294, CN2270, CN2271 (above, manufactured by SARTOMER) under the trade name. And aliphatic polyester oligomers.

The epoxy (meth)acrylate oligomer (A3) is a compound having a radically polymerizable functional group obtained by reacting an epoxy group of a compound having an epoxy group with a compound having a carboxyl group or a hydroxyl group. In the epoxy (meth)acrylate oligomer (A3), a small amount of epoxy groups may remain.

The epoxy type (meth)acrylate oligomer (A3) is, when it is referred to as a trade name, an aromatic epoxy oligomer such as CN104, CN110 (above, manufactured by SARTOMER), EBECRYL600, EBECRYL3701 (above, manufactured by Daicel Ornex), CN111, or the like. Aliphatic epoxy oligomers such as CN113 (above, manufactured by SARTOMER) and EBECRYL860 (manufactured by Daicel Ornex) are mentioned.

The (meth)acrylate oligomer (A) is contained in an amount of 1 to 30% by mass in a total of 100% by mass of the (meth)acrylate oligomer (A) (A) and the (meth)acrylate monomers (B) to (E) described later. Is preferably contained, and more preferably 2 to 20% by mass. The adhesive preferably contains 1% by mass or more of the (meth)acrylate oligomer (A) from the viewpoint of room temperature adhesive strength and high temperature suitability at a deformed site due to improvement in cohesive strength of the adhesive layer, and viscosity and coating suitability. From this point, it is preferable to contain 30% by weight or less of the acrylate oligomer (A).

<Mono(meth)acrylate (B) having an alicyclic structure>
As the mono(meth)acrylate (B) having an alicyclic structure (hereinafter, also referred to as an alicyclic monomer (B) or a compound (B)), one aliphatic hydrocarbon ring and (meth)acryloyl group are used. It is a monomer that has. By containing the compound (B), an active energy ray-polymerizable adhesive having excellent adhesive strength at high temperature can be obtained. The compound (B) has no amide group.

Examples of the compound (B) include cyclohexyl (meth)acrylate, 3,3,5-trimethylcyclohexanol (meth)acrylate, 4-tert-butyl-cyclohexyl (meth)acrylate, and 3,3-dicyclopropyl (meth)acrylate. , Dicyclopentenyl(meth)acrylate, dicyclopentenyloxyethyl-(meth)acrylate, dicyclopentanyl(meth)acrylate, isobornyl(meth)acrylate, 2-methyl-2-adamantyl(meth)acrylate, 2-ethyl Examples thereof include (meth)acrylate compounds having a condensed ring aliphatic hydrocarbon ring such as -2-adamantyl (meth)acrylate and 2-propyl-2-adamantyl (meth)acrylate.

As the compound (B), 3,3,5-trimethylcyclohexanol acrylate, dicyclopentenyl acrylate, dicyclopentenyl oxyethyl acrylate, dicyclopentanyl acrylate, isobornyl acrylate, from the viewpoint of excellent adhesive strength at high temperature. Are preferred, and isobornyl acrylate and 4-tert-butyl-cyclohexyl acrylate are particularly preferred.

The compound (B) is preferably 1 to 50% by mass, and 10 to 40% by mass in 100% by mass of the total of (A), (B), and (meth)acrylate monomers (C) to (E) described later. More preferable. When the compound (B) is used in an appropriate amount, the high temperature suitability at the deformed site is improved.

<Mono(meth)acrylate (C) having a hydroxyl group and no amide group>
Mono(meth)acrylate (C) having a hydroxyl group and having no amide group (hereinafter, also referred to as compound (C)) is a monomer having one hydroxyl group and one (meth)acryloyl group and no amide group. Is. The compound (C) has a high affinity with the base material and improves the adhesiveness, thereby contributing to the improvement of the adhesive force. In addition, since the compound (C) is less susceptible to oxygen inhibition and has excellent sensitivity to active energy rays, it contributes to the improvement of polymerizability at low irradiation.

The compound (C) is, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, (meth ) 6-Hydroxyhexyl acrylate, 8-hydroxyoctyl (meth)acrylate, cyclohexanedimethanol mono(meth)acrylate, 12-hydroxylauryl (meth)acrylate, ethyl (meth)acrylate-α-(hydroxy) Monofunctional glycerol (meth)acrylates such as methyl);
Fatty acid ester-based (meth)acrylic acid ester such as glycidyl lauric acid ester (meth)acrylic acid;

Cyclic rings such as cyclohexanedimethanol mono(meth)acrylate, cyclohexanediethanol mono(meth)acrylate, 2-hydroxy-3-phenoxypropyl(meth)acrylate, 2-a(meth)acryloyloxyethyl-2-hydroxyethyl-phthalic acid (Meth)acrylic acid ester;
A (meth)acrylic acid ester having a hydroxyl group at the molecular end synthesized by ring-opening addition of ε-caprolactone to these mono(meth)acrylates having a hydroxyl group;
Aliphatic (meth)acrylic acid esters and the like of alkylene oxide addition (meth)acrylic acid esters and the like in which alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide are repeatedly added to these mono(meth)acrylates having a hydroxyl group are included. ..
Note that cyclohexanedimethanol mono(meth)acrylate and cyclohexanediethanol mono(meth)acrylate are mono(meth)acrylates having an alicyclic structure, but those having a hydroxyl group and no amide group mono(meth)acrylate ( It is classified into C).

Among them, the compound (C) is suitable for low temperature and has excellent adhesiveness under low illuminance. 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxy (meth)acrylate. Propyl and 4-hydroxybutyl (meth)acrylate are preferred. The compound (C) can be used alone or in combination of two or more kinds.

The compound (C) is preferably 10 to 80% by mass in 100% by mass of the total of (A) to (C) and (meth)acrylate monomers (D) to (E) described later, and 20 to 70% by mass is preferable. More preferable. When the compound (C) is used in an appropriate amount, the polymerizability under low illuminance and the low temperature suitability at the deformed part are improved.

<(Meth)acrylate monomer (D) having a hydroxyl group and an amide group>
The (meth)acrylate monomer (D) having a hydroxyl group and an amide group (hereinafter, also referred to as compound (D)) is a monomer having a hydroxyl group and an amide group. The compound (D) does not have an alicyclic structure. The compound (D) has a high affinity with the base material and improves the adhesiveness, thereby contributing to the improvement of the adhesive force. Further, by having both a hydroxyl group and an amide group, the hydrogen bond strength is improved and the high temperature suitability is improved. Furthermore, since the compound (D) is less susceptible to oxygen inhibition and has excellent sensitivity to active energy rays, it contributes to the improvement of polymerizability under low irradiation. The amide group is preferably an aliphatic amide group.

Examples of the compound (D) having a hydroxyl group and an aliphatic amide group include N-hydroxyethyl (meth)acrylamide, N-hydroxypropyl (meth)acrylamide, N-hydroxybutyl (meth)acrylamide and N-hydroxy. Examples include hydroxyl group-containing (meth)acrylamides such as hexyl (meth)acrylamide, N-hydroxyoctyl (meth)acrylamide, and N-(4-hydroxyphenyl)(meth)acrylamide.

Among them, the compound (D) is preferably N-hydroxyethyl acrylamide because of its excellent adhesive strength and adhesive strength at low illuminance. Further, the compound (D) can be used alone or in combination of two or more kinds.

The compound (D) is preferably contained in an amount of 5 to 30% by mass, and preferably 8 to 25% by mass in a total of 100% by mass of (A) to (D) and a (meth)acrylate monomer (E) described later. Is more preferable. When the compound (D) is used in an appropriate amount, the high temperature suitability at the deformed portion and the polymerizability under low illuminance are improved, and the adhesive force is improved.

The adhesive of the present invention comprises a monomer having a hydroxyl group, that is, a compound (B) and a compound (C) in a total of 100% by mass of (A) to (D) and a (meth)acrylate monomer (E) described later. Is preferably contained in a total of 40 to 80% by mass, and more preferably 40 to 70% by weight. Use of an appropriate amount of a monomer having a hydroxyl group improves low temperature suitability, high temperature suitability, and polymerizability under low illuminance at a deformed portion.

The adhesive of the present invention may further contain a radical-polymerizable component (E) other than (B) to (D) (hereinafter, also referred to as compound (E)).

By containing the compound (E) in an appropriate amount that does not deteriorate the physical properties of the adhesive, the viscosity of the adhesive is lowered to improve the coatability, and the degree of crosslinking after curing is increased to improve the high temperature suitability. be able to.

The compound (E) may be a mono(meth)acrylate compound or a polyfunctional (meth)acrylate compound.
The compound (E) can be used alone or in combination of two or more kinds. Two or more mono(meth)acrylate compounds may be used in combination, two or more polyfunctional (meth)acrylate compounds may be used in combination, and a mono(meth)acrylate compound and polyfunctional (meth) may be used. ) It is also possible to use an acrylate compound together.

Examples of the mono(meth)acrylate compound include methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, n-hexyl acrylate, lauryl acrylate, and stearyl acrylate. (Meth)acrylic acid alkyl ester;

(Meth)acrylic acid perfluoroalkyl esters such as perfluoromethyl (meth)acrylate, 2-perfluoroethyl-ethyl (meth)acrylate, and 2-perfluorohexadecylethyl (meth)acrylate;
(Methoxycarbonyl)methyl (meth)acrylate, 2-(ethoxycarbonyloxy)hexyl (meth)acrylate, 2-(propoxycarbonyloxy)ethyl (meth)acrylate, and 2-(octyl) (meth)acrylate An aliphatic (meth)acrylic acid ester having one carbonyl group such as oxycarbonyloxy)butyl;
2-Oxobutanoylethyl (meth)acrylate, 3-oxobutanoylpropyl (meth)acrylate, 2,3-di(oxobutanoyl)butyl (meth)acrylate, 2,3-(meth)acrylate Aliphatic (meth)acrylic acid ester having two carbonyl groups such as di(oxobutanoyl)hexyl;

2-Methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-propoxyethyl (meth)acrylate, 3-propoxyethyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, Alkoxy group-containing (meth)acrylic acid ester such as 3-butoxyethyl (meth)acrylate and 4-butoxyethyl (meth)acrylate;
An alkylene oxide-containing (meth)acrylic acid derivative such as an alkylene oxide adduct of (meth)acrylic acid;

(Meth)acrylamide, N-methyl(meth)acrylamide, N-ethyl(meth)acrylamide, N-propyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-butyl(meth)acrylamide, N-propyl(meth ) Acrylamide, N-tert-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-octyl(meth)acrylamide, N-nonyl(meth)acrylamide, N-tricosyl(meth)acrylamide, N-nonadecyl(meth) ) Acrylamide, N-docosyl(meth)acrylamide, N-methylene(meth)acrylamide, N-tridecyl(meth)acrylamide, N-(5,5-dimethylhexyl), N,N-dimethyl(meth)acrylamide, N, Does not have a hydroxyl group such as N-diethyl-(meth)acrylamide, N-[3-(N',N'-dimethylamino)propyl]-(meth)acrylamide, N-(dibutylaminomethyl)(meth)acrylamide. Aliphatic (meth)acrylamides;

N-methoxymethyl (meth)acrylamide, N-methoxyethyl (meth)acrylamide, N-methoxypropyl (meth)acrylamide, N-methoxybutyl (meth)acrylamide, N-methoxyhexyl (meth)acrylamide, N-methoxyoctyl ( (Meth)acrylamide, N-methoxydecyl (meth)acrylamide, N-methoxydodecyl (meth)acrylamide, N-methoxyoctadecyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, N-ethoxyethyl (meth)acrylamide, N -Ethoxypropyl (meth)acrylamide, N-ethoxybutyl (meth)acrylamide, N-ethoxyhexyl (meth)acrylamide, N-ethoxyoctyl (meth)acrylamide, N-isopropoxymethyl (meth)acrylamide, N-isopropoxyethyl It has a hydroxyl group such as (meth)acrylamide, N-isopropoxypropyl(meth)acrylamide, N-isopropoxybutyl(meth)acrylamide, N-isopropoxyhexyl(meth)acrylamide, N-isopropoxyoctyl(meth)acrylamide. Examples include N-alkoxy group-containing (meth)acrylamides.

Examples of polyfunctional (meth)acrylate compounds include di(meth)acrylate, alkyleneoxy group-containing di(meth)acrylate, and polyol ester-based di(meth)acrylate. Examples of the trifunctional radically polymerizable monomer include tri(meth)acrylate. Examples of the tetrafunctional or higher functional radically polymerizable monomer include a tetrafunctional or higher functional (meth)acrylate.

Examples of the di(meth)acrylate include pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 2,2-dimethylpropane-1, Examples thereof include 3-diol di(meth)acrylate, hexanediol di(meth)acrylate, heptanediol di(meth)acrylate, nonanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate and the like.
Examples of the alkyleneoxy group-containing di(meth)acrylate include ethylene oxide-modified pentanediol di(meth)acrylate, propylene oxide-modified pentanediol di(meth)acrylate, tetramethylene oxide-modified pentanediol di(meth)acrylate, ethylene oxide-modified 2,2-Dimethylpropane-1,3-diol di(meth)acrylate, propylene oxide-modified 2,2-dimethylpropane-1,3-diol di(meth)acrylate, tetramethylene oxide-modified 2,2-dimethylpropane-1, 3-diol di(meth)acrylate, ethylene oxide-modified hexanediol di(meth)acrylate, propylene oxide-modified hexanediol di(meth)acrylate, tetramethylene oxide-modified hexanediol di(meth)acrylate, ethylene oxide-modified heptanediol di(meth) ) Acrylate, propylene oxide-modified heptanediol di(meth)acrylate, tetramethylene oxide-modified heptanediol di(meth)acrylate, ethylene glycol-propylene glycol di(meth)acrylate, diethylene glycol-propylene glycol di(meth)acrylate, diethylene glycol-di Propylene glycol di(meth)acrylate, poly(ethylene glycol-tetramethylene glycol) di(meth)acrylate, isocyanuric acid ethylene oxide modified di(meth)acrylate, isocyanuric acid propylene oxide modified di(meth)acrylate, isocyanuric acid butyl oxide modified Examples thereof include di(meth)acrylate and isocyanuric acid butyl oxide-modified di(meth)acrylate.
Examples of the polyol ester-based di(meth)acrylate include neopentyl glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate. ) Acrylate, tetramethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate and the like.

Examples of tri(meth)acrylate include trimethylolpropane tri(meth)acrylate, ethylene oxide-modified trimethylolpropane tri(meth)acrylate, propylene oxide-modified trimethylolpropane tri(meth)acrylate, and tetramethylene oxide-modified trimethylolpropane tri. (Meth)acrylate, propylene oxide 2 mol modified 2,2-dimethylpropane-1, ethylene oxide 3 mol modified trimethylolpropane tri(meth)acrylate, propylene oxide 3 mol modified trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth) Acrylate, propylene oxide 3 mol modified glycerin (meth)acrylate, isocyanuric acid ethylene oxide modified tri(meth)acrylate, isocyanuric acid propylene oxide modified tri(meth)acrylate, isocyanuric acid butyl oxide modified tri(meth)acrylate, isocyanuric acid butyl oxide modified Examples thereof include tri(meth)acrylate.

Examples of tetrafunctional or higher (meth)acrylates include dimethylolpropane tetra(meth)acrylate, ethylene oxide-modified dimethylolpropane tetra(meth)acrylate, prolene oxide-modified dimethylolpropane tetra(meth)acrylate, and tetramethylene oxide-modified. Examples thereof include dimethylolpropane tetra(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate, and dipentaerythritol hexa(meth)acrylate.

<Photopolymerization initiator (G)>
The photopolymerization initiator (G) is a compound that triggers a polymerization reaction by an active energy ray, and examples thereof include a photoradical polymerization initiator, a photocationic polymerization initiator, and a photoanionic polymerization initiator. The photopolymerization initiator (G) can be used alone or in combination of two or more kinds.
Commercially available photoradical polymerization initiators include, for example, OMNIRAD 184, 907, 651, 1700, 1800, 819, 369, 261, TPO (above, manufactured by IGM Resin Co., Ltd.), Darocur-1173 (manufactured by Merck Co., Ltd.), and Esacure. -KIP150, TZT (manufactured by Nippon Siber Hegna), Kayacure BMS, Kayacure DMBI, (above, manufactured by Nippon Kayaku Co., Ltd.) and the like.

Examples of commercially available photocationic polymerization initiators include UVACURE1590 (manufactured by Daicel Cytec), sulfonium salts such as CPI-110P (manufactured by San-Apro), OMINICAT250 (manufactured by IGM Resin), WPI-113 (Wako Pure). Iodonium salts such as Rp-2074 (produced by Rhodia Japan) and Yp Kogyo Co., Ltd. are listed.

Commercially available photoanion polymerization initiators include, for example, WPBG-165, WPBG-018, WPBG-172, WPBG-140, WPBG-166, WPBG-027, WPBG-082, WPBG-167, WPBG-168, WPBG-266 (above, Wako Pure Chemical Industries Ltd. make) etc. are mentioned.

The photopolymerization initiator (G) is preferably contained in an amount of 0.1 to 15 parts by mass, more preferably 0.5 parts by mass or more and 10 parts by mass with respect to 100 parts by mass in total of (A) to (E).

The adhesive of the present invention may further contain a photosensitizer, an amine-based catalyst, a phosphorus-based catalyst, a filler, an antistatic agent, an antioxidant, an antioxidant, a tackifier, an antiblocking agent, and a defoaming agent, if necessary. Agents, plasticizers, silane coupling agents, titanium coupling agents and the like can be contained.

The adhesive of the present invention preferably contains substantially no organic solvent, and more preferably contains no organic solvent at all. It is particularly preferable that the adhesive does not contain toluene. However, since the photopolymerization initiator (G) is difficult to dissolve in the monomer or oligomer, a small amount of organic solvent may be included in order to dissolve the photopolymerization initiator (G). In that case, the content of the organic solvent in the adhesive is preferably 5% by mass or less.

The adhesive of the present invention can contain other additives as long as the problems can be solved. Other additives include, for example, photosensitizers, amine-based catalysts, phosphorus-based catalysts, fillers, antistatic agents, antioxidants, antioxidants, tackifiers, antiblocking agents, defoamers, plasticizers, etc. Can be mentioned.

The adhesive of the present specification preferably has a viscosity at 25° C. of 1 to 2000 mPa·s, more preferably 10 to 1500 mPa·s, in order to improve the smoothness of the surface of the adhesive layer and facilitate the thickness control. It is preferably 20 to 1000 mPa·s and more preferably 20 mPa·s. The viscosity is a value measured 1 minute after the start of rotation, which was measured with an E-type corn rotor viscometer at 1°34'×R24 rotor at 10 rotations/minute.

The adhesive of the present specification can be prepared by mixing the materials described above and stirring.

When the adhesive is used as the adhesive layer of the optical laminate, the thickness of the adhesive layer is preferably 0.1 to 6 μm, more preferably 0.1 to 3 μm. When the thickness of the adhesive layer is within the above range, the adhesive strength is further improved.

A known coating device can be used for coating the adhesive with the base material. For example, wire bar, applicator, brush, sprayer, roller, gravure coater, die coater, micro gravure coater, lip coater, comma coater, Carter coater, knife coater, river coater, spin coater and the like can be mentioned.

The active energy ray used for curing the adhesive is preferably light including ultraviolet rays, and the wavelength in that case is preferably 150 to 550 nm. Examples of the light source of active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, LED lamps, xenon lamps, and metal halide lamps. ..

The irradiation intensity of the active energy ray is preferably 10 to 500 mW/cm ² . Integrated irradiation dose, expressed as the product of the irradiation intensity and the irradiation time is preferably ^{10~5000mJ / cm 2, 30~4000mJ / cm} 2 is more preferable.

The laminate of the present invention includes a first base material, an adhesive layer formed from the adhesive of the present invention, and a second base material.

The polymerization reaction of the adhesive proceeds when the adhesive is applied or when laminating, and further by irradiating with active energy rays after further laminating, but after laminating the base material, irradiating with active energy rays. It is preferable to proceed the polymerization reaction. At this time, in order to proceed the polymerization reaction by irradiation with active energy rays, at least one of the first base material and the second base material is preferably composed of a material that easily transmits active energy rays, Specifically, a transparent film, a plastic lens, a transparent glass plate, etc. are preferable. For example, if a transparent film or a transparent glass plate is used as the first base material, a base material that is difficult for active energy rays to pass through as the second base material, for example, wood, a metal plate, a plastic plate, a processed paper product, etc. You may use it.

In the laminate of the present invention, it is preferable to use a film-shaped substrate as the substrate. Examples of the film-shaped substrate include cellophane, various plastic films, paper and the like. Above all, it is preferable to use various transparent plastic films. Further, the film-shaped substrate may have a single layer or a multi-layered structure in which a plurality of substrates are laminated as long as the film is transparent.

Hereinafter, more specific embodiments of the optical layered body of the present invention will be described by taking a case where a transparent film is used as a substrate as an example.

The laminate of the present invention is a sheet-like product obtained by laminating a plurality of transparent films such as transparent film/adhesive layer/transparent film or transparent film/adhesive layer/transparent film/adhesive layer/transparent film. It is a multilayer film. Further, it is also preferable that the sheet-shaped multilayer film is adhered to another optical member such as glass or an optical sheet. The laminate can be obtained by curing the adhesive layer by irradiating the active energy ray-polymerizable adhesive for optics with an active energy ray from one side or both sides of the film to polymerize and cure the adhesive.

Examples of the transparent film include a polyvinyl alcohol film, a polytriacetyl cellulose film, polypropylene, polyethylene, polycycloolefin, and a polyolefin-based film such as ethylene-vinyl acetate copolymer; a polyester-based film such as polyethylene terephthalate and polybutylene terephthalate. A polycarbonate film, a polynorbornene film, a polyarylate film, a polyacrylic film, a polyphenylene sulfide film, a polystyrene film, a polyvinyl film, a polyamide film, a polyimide film, and a polyoxirane film. ..
When a transparent film is used as the substrate, the laminate of the present invention can be suitably used for optical applications.

The thickness of the transparent film can be appropriately determined, but in general, 1 to 500 μm is preferable, 1 to 300 μm is more preferable, and 5 to 200 μm, from the viewpoint of film strength, workability, thin layer property and the like. More preferable. When used for optical applications, the thickness of the transparent film is preferably 5 to 150 μm.

As an example of the embodiment of the optical layered body of the present invention, the layered body for optical elements, it is preferable to use an optical film mainly used for optical applications as a transparent film.

The optical film includes, for example, a hard coat film, an antistatic coat film, an antiglare coat film, a polarizing film, a retardation film, an elliptically polarizing film, an antireflection film, a light diffusing film, a brightness improving film, a prism film (prism film). -Also referred to as a sheet), a decorative film (including a filling sheet for a touch panel), a light guide film (also referred to as a light guide plate), a touch sensor film (a film having a transparent conductive layer), and the like.

The active energy ray-polymerizable adhesive for optics of the present invention can be used to form a laminate of a liquid crystal display device, a PDP module, a touch panel module, an organic EL module or the like.

<Weight average molecular weight>
The weight average molecular weight was measured by using Showa Denko GPC (gel permeation chromatography) “Shodex GPC System-21” as a measuring device, using Showa Denko SHODX GPC LF-604 as a column, and using tetrahydrofuran (Development Solvent) as a developing solvent. THF), a flow rate of 0.6 ml/min, and a column temperature of 40°C. The weight average molecular weight was determined by a calibration curve prepared by using polystyrene having a known weight average molecular weight as a standard substance and having a monodisperse molecular weight.

[Example 1]
<Production example of adhesive>
In a light-shielded glass bottle with a capacity of 300 mL, 15 parts of UV3300B (polyether skeleton urethane acrylate oligomer, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name Shikko UV3300B) as (meth)acrylate oligomer (A), and isobornyl as compound (B) 20 parts of acrylate, 55 parts of 4-hydroxybutyl acrylate as compound (C), 10 parts of N-hydroxyethylacrylamide as compound (D), 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide 3 as compound (G) Parts were added, and the mixture was thoroughly stirred and defoamed to obtain an active energy ray-polymerizable adhesive.

<Example of manufacturing laminated body>
As the transparent film, an acrylic film HBD-022 (thickness 50 μm, manufactured by Mitsubishi Rayon Co., Ltd.) and a polynorbornene-based film containing no ultraviolet absorber (thickness 100 μm manufactured by ZEON CORPORATION) were used. Corona treatment was performed on one surface of each of the two transparent films at a discharge rate of 300 W·min/m ² . Within 1 hour after that, the obtained adhesive was applied on the corona-treated surface of the acrylic film HBD-022 by using a wire bar coater so that the thickness was 2 μm to form an adhesive layer. Further, a polynorbornene-based film containing no ultraviolet absorber was layered, and the four sides were fixed to the tin plate with cellophane tape so that the acrylic film was in contact with the tin plate.

Using an active energy ray irradiation device (high pressure mercury lamp manufactured by Toshiba Corp.), under the condition of a maximum illuminance of 200 mW/cm ² , from the polynorbornene-based film side that does not contain the above-mentioned ultraviolet absorber, an integrated light amount of 600 mJ/cm ² of ultraviolet light is emitted. Then, the laminate 1 was created by storing it in an environment of 25°C-50% for 1 day or more. A layered product 2 was prepared in the same manner except that the integrated light amount was changed to 300 mJ/cm ² .
Regarding the obtained laminates 1 and 2, the initial adhesive strength, the adhesive strength after high temperature storage at the deformed portion, and the adhesive strength after low temperature storage at the deformed portion were evaluated. The results are shown in Tables 1 to 3.

<Initial adhesion test>
The adhesive force was measured according to JIS K6854-4 Adhesive-Peeling Adhesive Strength Test Method-Part 4: Floating Roller Method.
That is, the obtained laminated bodies 1 and 2 were cut into a size of width 25 mm×length 150 mm using a cutter to prepare a measurement sample. A double-sided pressure-sensitive adhesive tape (DF8712S manufactured by Toyochem Co., Ltd.) was attached to one surface of the sample, and the sample was adhered onto a metal plate using a laminator. The measurement laminate is provided with a peeling maker in advance between the transparent films, and the measurement laminates 1 and 2 are 300 mm/min at a temperature of 23° C. and a relative humidity of 50%. The adhesive strength was measured at an angle of 90°. The adhesive force was measured by peeling off the acrylic film HBD-022. The adhesive strength was evaluated according to the following four grades. It should be noted that the evaluation criteria are practically no problem if the evaluation criteria are ⊚, ◯ and Δ.
A: Peeling force is 4.0 (N/25 mm) or more (very good)
◯: Peeling force is 2.0 (N/25 mm) or more and less than 4.0 (N/25 mm) (good)
Δ: Peel force is 1.0 (N/25 mm) or more and less than 2.0 (N/25 mm) (usable)
X: Peeling force is less than 1.0 (N/25 mm) (cannot be used)

<<Bending deformation Adhesion test after storage at high temperature>>
High temperature suitability was evaluated by the following adhesive strength.
In a state where the obtained laminated body 1 of the obtained laminated body 1 was wound so as to be in contact with the polynorbornene-based film containing no ultraviolet absorber, and the end portion of the laminated body 1 was fixed with cellophane tape. After being stored at 80° C. and a relative humidity of 50% RH for 1 month, the laminated body 1 was removed from the metal cylinder, and the adhesive force of the laminated body 1 was measured and evaluated. The laminate 2 was also measured and evaluated in the same manner as the laminate 1.
The measuring method and the evaluation standard of the adhesive force are the same as those of the initial adhesive force.

《Adhesion test after bending deformation low temperature storage》
The low temperature suitability was evaluated by the following adhesive strength.
Adhesive strength was measured in the same manner as in the adhesive strength test after curved deformation high temperature storage, except that the laminated bodies 1 and 2 wound and fixed on a metal cylinder were stored at -20°C for 1 month. It was evaluated by.

[Examples 2 to 19], [Comparative examples 1 to 5]
According to the compositions shown in Tables 1 and 2, adhesives were obtained in the same manner as in Example 1 to form laminates 1 and 2 and evaluated in the same manner.

The materials used in Examples and Comparative Examples and their abbreviations are shown below.
<(Meth)acrylate oligomer (A)>
UV3300B: Polyurethane-based polyurethane-based acrylate oligomer, weight average molecular weight 13000, (Nippon Gosei Kagaku Kogyo Co., Ltd., trade name Shikko UV3300B)

UV3000B: Polyurethane-based polyurethane acrylate oligomer, weight average molecular weight 18000, (Nippon Gosei Kagaku Kogyo Co., Ltd., trade name Shikko UV3300B)

EBECRYL884: Polyester-based acrylate oligomer Weight average molecular weight 3000 (manufactured by Daicel Ornex)

EBECRYL 860: Epoxy acrylate oligomer, weight average molecular weight 1200
(Manufactured by Daicel Ornex),

<Compound (B)>
IBXA: Isobornyl acrylate, manufactured by Osaka Organic Chemical Industry, trade name IBXA
SR217: 4-tert-butylcyclohexanol acrylate manufactured by SARTOMER

<Compound (C)>
4-HBA: 4-hydroxybutyl acrylate HPA: 2-hydroxypropyl acrylate HEA: 2-hydroxyethyl acrylate

<Compound (D)>
HEAA: N-hydroxyethylacrylamide (manufactured by KJ Chemicals)

<Compound (E)>
A-NOD-N: Nonanediol diacrylate (Shin-Nakamura Chemical Co., Ltd.)
DMAA: N,N-dimethylacrylamide (manufactured by KJ Chemicals)

<Photopolymerization initiator (G)>
OMNIRAD TPO: 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (manufactured by IGM Resins)

<Sensitizer>
DETX-S: 2,4-diethylthioxanthone (Nippon Kayaku Co., Ltd.)

As shown in Tables 1 and 2, the adhesives of Examples 1 to 19 are excellent in not only the initial adhesive force but also the adhesive force after the bending deformation high temperature storage and after the bending deformation low temperature storage even when the integrated light amount is small. Can form a body.

Claims (7)

An adhesive containing a (meth)acrylate oligomer (A) having a weight average molecular weight of 1000 or more and a (meth)acrylate monomer having a weight average molecular weight of less than 1000, comprising:
The (meth)acrylate monomer has a monocyclic (meth)acrylate (B) having an alicyclic structure, a mono(meth)acrylate (C) having a hydroxyl group and no amide group, and a hydroxyl group and an amide group ( An adhesive which contains a (meth)acrylate (D) and can further contain a radically polymerizable component (E) other than the above (A) to (D),
40% to 80% by mass of a monomer having a hydroxyl group is contained in the total 100% by mass of (A) to (E).
adhesive. The adhesive according to claim 1, wherein the (meth)acrylate oligomer (A) is a polyurethane-based (meth)acrylate oligomer (A1). The adhesive according to claim 2, wherein the polyurethane-based (meth)acrylate oligomer (A1) is a polyurethane-based (meth)acrylate oligomer (A1-1) having a polyether skeleton. 4. The (meth)acrylate monomer (D) having a hydroxyl group and an amide group is contained in an amount of 5 to 30% by mass in 100% by mass of the total of (A) to (E). The adhesive described in. The adhesive according to any one of claims 1 to 4, wherein the (meth)acrylate oligomer (A) is contained in an amount of 1 to 30% by mass based on 100% by mass of the total of (A) to (E). The adhesive according to claim 1, further comprising a photopolymerization initiator. A laminate comprising a first substrate, an adhesive layer that is a cured product of the adhesive according to any one of claims 1 to 6, and a second substrate.