JP7398203B2 - Adhesive sheet for image display devices - Google Patents

Description

The present invention relates to an adhesive sheet for an image display device and an adhesive sheet laminate for an image display device.

BACKGROUND ART In recent years, adhesive sheets such as those described in Patent Document 1, for example, have been used to bond and laminate cover films, electrode films, casings, etc. that constitute touch panel displays used in smartphones and the like.

Japanese Patent Application Publication No. 2012-025808

Incidentally, in recent years, some image display devices such as touch panel displays have curved or bent surfaces, and are often bent repeatedly. You need to follow it and paste it. However, when a cover film is attached to such a curved surface, there is a risk that the cover film may crack or peel, and an improvement has been desired. The present invention has been made to solve the above problems, and provides an adhesive for image display devices that can prevent cracking or peeling of the cover film when attaching the cover film to the image display device. An object of the present invention is to provide a sheet and an adhesive sheet laminate for an image display device.

Item 1. (meth)acrylic acid ester copolymer as the main component,
An isocyanate crosslinking agent,
Rosin ester tackifier resin,
Contains
For an image display device comprising 1 to 40 parts by weight of the rosin ester tackifying resin based on 100 parts by weight of the (meth)acrylic acid ester copolymer, and comprising an adhesive layer containing a crosslinked adhesive composition. An adhesive sheet,
The adhesive layer has a maximum value of tan δ at 1 Hz of −20° C. or less,
The adhesive layer is an adhesive sheet for an image display device, and the storage elastic modulus at 1 Hz and 25° C. is 1.0×10 ⁵ Pa or less.

Item 2. The pressure-sensitive adhesive sheet for an image display device according to item 1, which has a storage modulus of 1.0×10 ⁵ Pa or less at -20° C. and 1.1 Hz.

Item 3. Item 2. The pressure-sensitive adhesive sheet for an image display device according to Item 1 or 2, having a thickness of 5 to 100 μm.

Item 4. A base sheet for peeling, which is attached to at least one surface of the adhesive sheet for an image display device according to any one of Items 1 to 3;
An adhesive sheet laminate for image display devices, comprising:

According to the adhesive sheet according to the present invention, it is possible to prevent the cover film from cracking or peeling off when the cover film is attached to an image display device.

FIG. 1 is a cross-sectional view of a pressure-sensitive adhesive sheet laminate according to an embodiment of the present invention. FIG. 3 is a cross-sectional view of a test piece for a bending test. It is a figure showing the method of a bending test.

Hereinafter, one embodiment of the adhesive sheet according to the present invention will be described. This adhesive sheet is an adhesive sheet for attaching cover films, electrode films, casings, etc. that make up image display devices such as touch panel displays, and is especially used for attaching cover films to displays with curved or bent surfaces. Suitably used. This adhesive sheet is a crosslinked adhesive composition containing a (meth)acrylic acid ester copolymer as a main component, an isocyanate crosslinking agent, and a rosin ester tackifying resin. This will be explained in detail below.

<1. (Meth)acrylic acid ester copolymer>
(Meth)acrylic acid ester polymer is made by combining (meth)acrylic acid alkyl ester whose alkyl group has 2 to 20 carbon atoms and a monomer having a reactive functional group in the molecule (reactive functional group-containing monomer). It is preferable to contain it as a monomer unit. Thereby, preferable adhesiveness can be developed.

(Meth)acrylic acid alkyl esters whose alkyl group has 2 to 20 carbon atoms are those whose glass transition temperature (Tg) as a homopolymer is -40°C or lower (hereinafter sometimes referred to as "specific acrylates"). is preferred. By containing such a specific acrylate as a constituent monomer unit, it becomes easy to set the maximum value of tan δ of the pressure-sensitive adhesive sheet according to this embodiment within the range described below.

Specific acrylates include, for example, n-butyl acrylate (Tg-55°C), n-octyl acrylate (Tg-65°C), isooctyl acrylate (Tg-58°C), and 2-ethylhexyl acrylate (Tg-70°C). ), isononyl acrylate (Tg - 58°C), isodecyl acrylate (Tg - 60°C), isodecyl methacrylate (Tg - 41°C), n-lauryl methacrylate (Tg - 65°C), tridecyl acrylate (Tg -55°C), tridecyl methacrylate (-40°C), etc. are preferably used. Among them, from the viewpoint of more effectively reducing the storage modulus, it is more preferable that the homopolymer has a Tg of -45°C or less, and preferably -50°C or less as the specific acrylate. Particularly preferred. Specifically, n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferred. These may be used alone or in combination of two or more. Note that the alkyl group in the (meth)acrylic acid alkyl ester having an alkyl group having 2 to 20 carbon atoms refers to a linear, branched, or cyclic alkyl group.

The (meth)acrylic acid ester polymer preferably contains 60% by mass or more of the specific acrylate as a monomer unit, more preferably 80% by mass or more, and particularly preferably 90% by mass or more. By containing the above specific acrylate in an amount of 60% by mass or more, it becomes easier to set the maximum value of tan δ of the pressure-sensitive adhesive sheet according to the present embodiment within the range described below.

Further, the (meth)acrylic acid ester polymer preferably contains 99.9% by mass or less, more preferably 99% by mass or less, and preferably 98% by mass or less of the specific acrylate as a monomer unit. is particularly preferred. By containing the above specific acrylate at 99.9% by mass or less, a suitable amount of other monomer components (especially reactive functional group-containing monomers) can be introduced into the (meth)acrylic acid ester polymer.

By containing a reactive functional group-containing monomer as a monomer unit, the (meth)acrylic acid ester polymer reacts with the crosslinking agent described below via the reactive functional group derived from the reactive functional group-containing monomer, As a result, a crosslinked structure (three-dimensional network structure) is formed, and a pressure-sensitive adhesive sheet having a desired cohesive force is obtained.

The reactive functional group-containing monomers contained in the (meth)acrylic acid ester polymer as monomer units include monomers having a hydroxyl group in the molecule (hydroxyl group-containing monomer), monomers having an amino group in the molecule (amino group-containing monomer), ) etc. are preferred. Among these, hydroxyl group-containing monomers are particularly preferred. Many of the hydroxyl group-containing monomers have a glass transition temperature (Tg) of 0° C. or lower, and it is easy to set the maximum value of tan δ of the adhesive sheet according to the present embodiment within the range described below.

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, and ) 3-hydroxybutyl acrylate, 4-hydroxybutyl (meth)acrylate, and other hydroxyalkyl (meth)acrylates. Among them, 2-hydroxyethyl acrylate is preferred in terms of glass transition temperature (Tg), reactivity of the hydroxyl group in the obtained (meth)acrylic acid ester polymer with a crosslinking agent, and copolymerizability with other monomers. , 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, and 4-hydroxybutyl acrylate. These may be used alone or in combination of two or more.

The hydroxyl value of the (meth)acrylic acid ester copolymer is not particularly limited, but from the viewpoint of suppressing peeling from the adherend when the adhesive sheet is repeatedly bent while in close contact with the adherend, the lower limit is set. Regarding the amount, preferably 5 mgKOH/g or more, more preferably 10 mgKOH/g or more. On the other hand, the upper limit is preferably 100 mgKOH/g or less, more preferably 90 mgKOH/g or less.

The (meth)acrylic acid ester polymer preferably contains a reactive functional group-containing monomer in a monomer unit of 0.1% by mass or more, more preferably 0.5% by mass or more, and 1% by mass. It is particularly preferable to contain the above amount. The (meth)acrylic acid ester polymer preferably contains a reactive functional group-containing monomer as a monomer unit at 30% by mass or less, more preferably at most 20% by mass, and more preferably at most 8% by mass. It is particularly preferable to do so.

However, the (meth)acrylic acid ester polymer according to the present embodiment does not contain a carboxy group-containing monomer, especially acrylic acid, as a monomer unit. Carboxy groups are acid components, so by not containing a carboxy group-containing monomer, the adhesive sheet can be attached to objects that may cause problems due to acids, such as transparent conductive films such as tin-doped indium oxide (ITO), metal films, etc. Even when a metal mesh or the like is present, problems caused by acid (corrosion, change in resistance value, etc.) can be suppressed.

The polymerization mode of the (meth)acrylic acid ester polymer may be a random copolymer or a block copolymer.

The lower limit of the weight average molecular weight of the (meth)acrylic acid ester polymer is preferably 200,000 or more, more preferably 300,000 or more, and particularly preferably 400,000 or more. When the lower limit of the weight average molecular weight of the (meth)acrylic acid ester polymer is equal to or higher than the above value, problems such as oozing of the adhesive during processing of the adhesive sheet are suppressed. Note that the weight average molecular weight in this specification is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

Further, the upper limit of the weight average molecular weight of the (meth)acrylic acid ester polymer is preferably 1,000,000 or less, more preferably 900,000 or less, and particularly preferably 800,000 or less. When the upper limit of the weight average molecular weight of the (meth)acrylic acid ester polymer is below the above range, the adhesive strength and storage elastic modulus of the resulting pressure-sensitive adhesive sheet to the adherend tend to fall within the preferred range described below.

In addition, in the adhesive according to this embodiment, one type of (meth)acrylic acid ester polymer mentioned above may be used alone, or two or more types may be used in combination.

<2. Isocyanate crosslinking agent>
When the adhesive composition according to this embodiment is heated, the isocyanate-based crosslinking agent crosslinks the (meth)acrylic acid ester polymer to form a three-dimensional network structure. This improves the cohesive force of the resulting pressure-sensitive adhesive sheet.

The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, and alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate. and their biuret forms, isocyanurate forms, and adduct forms which are reactants with low-molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil. Among these, trimethylolpropane-modified aromatic polyisocyanates, particularly trimethylolpropane-modified tolylene diisocyanate and trimethylolpropane-modified xylylene diisocyanate, are preferred from the viewpoint of reactivity with hydroxyl groups.

The content of the isocyanate crosslinking agent in the adhesive composition is preferably 0.01 parts by mass or more, particularly 0.05 parts by mass or more, based on 100 parts by weight of the (meth)acrylic acid ester polymer. The amount is preferably 0.1 part by mass or more, and more preferably 0.1 part by mass or more. Further, the content is preferably 10 parts by mass or less, particularly preferably 8 parts by mass or less, and further preferably 5 parts by mass or less.

<3. Rosin ester tackifier resin>
The rosin ester tackifying resin according to the present embodiment includes gum rosin, wood rosin, tall oil rosin, etc., which have resin acids such as abietic acid, parastophosphoric acid, neoabietic acid, pimaric acid, isopimaric acid, and dehydroabietic acid as a main component. This is a rosin ester tackifying resin that is an ester of a rosin tackifying resin and various alcohols.

The content of the rosin ester tackifying resin in the adhesive composition is preferably 1 to 40 parts by weight, and 1.5 to 35 parts by weight, based on 100 parts by weight of the (meth)acrylic acid ester polymer. 1 part by weight, and even more preferably 2 to 30 parts by weight. When the content is 1 part by weight or more, the bending resistance when the cover film is attached to an image display device using an adhesive sheet is improved. On the other hand, by controlling the content to 40 parts by weight or less, clouding of the pressure-sensitive adhesive sheet can be suppressed.

<4. Additive>
The adhesive composition may optionally contain various additives commonly used in acrylic adhesives, such as silane coupling agents, ultraviolet absorbers, antistatic agents, tackifiers, antioxidants, Light stabilizers, softeners, fillers, refractive index modifiers, etc. can be added. Note that the polymerization solvent and dilution solvent described below are not included in the additives constituting the adhesive composition.

<5. Physical properties of adhesive sheet>
<5-1. Adhesive sheet thickness>
The thickness of the adhesive sheet is preferably 5 to 100 μm, more preferably 10 to 50 μm. This is because if the thickness is less than 5 μm, the cover film may easily peel off. On the other hand, if the thickness exceeds 100 μm, the cover film will sink when pressed, which may reduce the pencil hardness.

<5-2. Storage modulus and tan δ>
The adhesive sheet according to this embodiment has a maximum value of tan δ (glass transition temperature) of -20°C or less at 1 Hz, and a storage modulus of 1.0 x 10 ⁵ Pa or less at 1 Hz and 25°C. The lower the maximum value of tan δ, the lower the storage modulus and the softer the adhesive sheet. Therefore, the maximum value of tan δ of the adhesive sheet at 1 Hz is preferably -30°C or less, more preferably -50°C or less. The storage modulus of the adhesive sheet at 1 Hz and 25° C. is preferably lower, preferably 1.0×10 ⁵ Pa or less, more preferably 8.0×10 ⁴ Pa or less, 5. It is more preferably 0×10 ⁴ Pa or less, particularly preferably 3.0×10 ⁴ Pa or less. In addition, in order to maintain softness even at low temperatures, the storage elastic modulus of the adhesive sheet at 1 Hz and -20°C is preferably 1.0 x 10 ⁵ Pa or less, and 7.0 x 10 ⁴ Pa or less. is more preferable, and particularly preferably 5.5×10 ⁴ Pa or less.

The maximum value of tan δ can be measured using, for example, "Discovery HR-3" manufactured by TA Instruments, and the storage modulus can be measured by a method in accordance with JIS K7244-6. be able to.

<6. Adhesive sheet manufacturing method>
The method for manufacturing the adhesive sheet according to the present embodiment is not particularly limited, but can be performed as follows, for example.

First, a (meth)acrylic acid ester polymer, an isocyanate crosslinking agent, and a rosin ester tackifying resin are mixed, and the above-mentioned additives are added as necessary.

The (meth)acrylic acid ester polymer can be produced by polymerizing a mixture of monomers constituting the polymer using a conventional radical polymerization method. The (meth)acrylic acid ester polymer is preferably polymerized by a solution polymerization method using a polymerization initiator if necessary. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, and methyl ethyl ketone, and two or more of them may be used in combination.

Examples of the polymerization initiator include azo compounds and organic peroxides, and two or more types may be used in combination. Examples of azo compounds include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane 1-carbonitrile), 2 ,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl 2,2'-azobis(2-methylpropionate) , 4,4'-azobis(4-cyanovaleric acid), 2,2'-azobis(2-hydroxymethylpropionitrile), 2,2'-azobis[2-(2-imidazolin-2-yl) Propane], etc.

Examples of organic peroxides include benzoyl peroxide, t-butyl perbenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di(2-ethoxyethyl)peroxy Examples include dicarbonate, t-butyl peroxyneodecanoate, t-butyl peroxy bivalate, (3,5,5-trimethylhexanoyl) peroxide, dipropionyl peroxide, diacetyl peroxide and the like.

In the above polymerization step, the weight average molecular weight of the resulting polymer can be adjusted by incorporating a chain transfer agent such as 2-mercaptoethanol.

Once the (meth)acrylic ester polymer is obtained, an isocyanate crosslinking agent, a rosin ester tackifier resin, and optionally additives and a diluting solvent are added to the solution of the (meth)acrylic ester polymer, By thoroughly mixing, a solvent-diluted adhesive composition (coating solution) is obtained.

In addition, if any of the above components is used in solid form, or if precipitation occurs when mixed with other components in an undiluted state, that component alone must be diluted with a diluting solvent in advance. It may be mixed with other components after being dissolved or diluted.

Examples of the diluent include aliphatic hydrocarbons such as hexane, heptane, and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride, and ethylene chloride, methanol, ethanol, propanol, butanol, Alcohols such as 1-methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone, esters such as ethyl acetate and butyl acetate, and cellosolve solvents such as ethyl cellosolve are used.

The concentration and viscosity of the coating solution thus prepared may be within a range that allows coating, and can be appropriately selected depending on the situation. For example, the adhesive composition can be diluted to a concentration of 10 to 60% by mass. In addition, when obtaining a coating solution, addition of a diluting solvent and the like is not a necessary condition, and as long as the adhesive composition has a viscosity that allows coating, it is not necessary to add a diluting solvent. In this case, the adhesive composition becomes a coating solution using the polymerization solvent of the (meth)acrylic acid ester polymer as a diluting solvent.

Crosslinking of the above-mentioned adhesive composition can usually be carried out by heat treatment. Note that this heat treatment can also serve as a drying treatment when evaporating the diluting solvent and the like from the coating film of the adhesive composition applied to the desired object.

The heating temperature of the heat treatment is preferably 50 to 150°C, more preferably 70 to 120°C. Further, the heating time is preferably, for example, 10 seconds to 10 minutes, and more preferably 50 seconds to 2 minutes.

After the heat treatment, if necessary, a curing period of about 1 to 2 weeks can be provided at room temperature (for example, 23° C., 50% RH). If this curing period is necessary, the adhesive sheet is formed after the curing period has elapsed. On the other hand, if a curing period is not required, an adhesive sheet is formed after the heat treatment is completed.

By the above heat treatment (and curing), the (meth)acrylic acid ester polymer is sufficiently crosslinked via the isocyanate crosslinking agent to form a crosslinked structure, and a pressure-sensitive adhesive sheet is obtained.

<7. Adhesive sheet laminate＞
Next, the adhesive sheet laminate according to this embodiment will be explained. As shown in FIG. 1, the adhesive sheet laminate according to the present embodiment includes a first release sheet 1, an adhesive layer 2 laminated on the first release sheet 1, and an adhesive layer 2 disposed on the adhesive layer 2. A second release sheet 3 is provided. The first and second release sheets 1 and 3 are known release sheets, and have a release surface on at least one of them.

This adhesive sheet laminate can be manufactured, for example, as follows. First, the first release sheet 1 is fed out from a feed roll that has wound up the first release sheet 1. Then, a coating liquid of the above-described adhesive composition is applied to the release surface of the first release sheet 1, and heat treatment is performed to thermally crosslink the adhesive composition, thereby forming the adhesive layer 2. This adhesive layer 2 corresponds to the adhesive sheet of the present invention. Thereafter, a second release sheet 3 is attached so as to cover this adhesive layer 2. At this time, the release surface of the second release sheet 3 is brought into contact with the adhesive layer 2. In this way, a pressure-sensitive adhesive sheet laminate as shown in FIG. 1 is formed.

<8. Cover film>
The cover film to be attached to the image display device via the above-mentioned adhesive sheet is not particularly limited, and any known cover film can be used. There are various methods for attaching the above-mentioned adhesive sheet to the cover film. For example, after peeling off the first or second release sheet of the adhesive sheet laminate described above, the exposed adhesive layer can be transferred to the cover film, thereby attaching it to the cover film. Alternatively, an adhesive layer (adhesive sheet) can be formed by applying the above-mentioned adhesive composition coating solution to one side of the cover film and heat-treating the adhesive composition to thermally crosslink the adhesive composition. can.

<9. Features>
Since the adhesive sheet according to the present invention has a low storage modulus and contains a rosin ester adhesive resin, a cover film provided with this adhesive sheet is pasted along an image display device having a bent portion. At this time, stress acting on the cover film due to bending can be alleviated by the adhesive sheet. Therefore, it is possible to prevent cracks and peeling from occurring when the cover film is bent.

Next, examples of the present invention will be described. However, the present invention is not limited to the following examples.

<1. Preparation of Examples and Comparative Examples>
Adhesive sheets according to Examples 1 to 7 and Comparative Examples 1 to 4 were prepared. Furthermore, a cover film was attached to the target film using each adhesive sheet to produce a laminate as shown in FIG. 2. The cover film and target film are as follows.
(1) Cover film: Acrylic resin film that does not crack at R = 3.0 mm in a 100 μm thick bending test.
(2) Target film: 30 μm thick polyimide resin film Note that the target film is intended for an image display device to which a cover film is attached.

The compositions of the adhesives according to Examples 1 to 7 and Comparative Examples 1 to 4 are as follows. Coronate L-55E constituting the isocyanate-based crosslinking agent is manufactured by Tosoh Corporation, BXX8515 is manufactured by Toyo Ink Company, and Duranate TPA-100 is manufactured by Asahi Kasei Corporation. Moreover, Pine Crystal ME-GH constituting the rosin ester tackifying resin is manufactured by Arakawa Chemical Industry Co., Ltd. For acrylic ester copolymers, weight average molecular weight and hydroxyl value are shown.

The physical property values of the pressure-sensitive adhesive sheets according to Examples 1 to 7 and Comparative Examples 1 to 4 are as follows.

The storage modulus and loss tangent tan δ of the adhesive sheet were measured using "Discovery HR-3" manufactured by TA Instruments. The measurement conditions are as follows.
(Measurement condition)
Measurement mode: shear mode Strain: 0.1%
Measurement frequency: 1Hz
Measurement temperature: -60 to 25℃ (temperature increase 5℃/min)
Measurement sample: The adhesive layers of each adhesive sheet were stacked to have a total thickness of about 1 mm, and the measurement was made.

Further, for each adhesive sheet, the total light transmittance and haze rate were measured in a laminated structure of glass/adhesive sheet/PET film. The total light transmittance was measured according to JIS K7136-1, and the haze was measured according to JIS K7136. The results are shown in Table 3.

Furthermore, a bending test was conducted on the laminate shown in FIG. 2 using each pressure-sensitive adhesive sheet. For the bending test, a no-load U-shaped testing machine shown in FIG. 3 was used. This testing machine has two rotatable movable plates, and the rotating axes of the movable plates are arranged close to each other so that the rotating axes of the movable plates are parallel to each other. Then, the laminate, which was a sample piece, was placed on the horizontal movable plate shown in FIG. 3(a). At this time, the laminate was arranged so that the cover film surface of the laminate was in contact with the movable plate. Subsequently, as shown in FIG. 3(b), both movable plates were turned 90 degrees to bend the sample piece into a U-shape. Such bending was repeated at room temperature at a test speed of 0.85 seconds/time. After the test, it was confirmed whether or not cracks occurred in the cover film of the sample piece, and the bending resistance was evaluated using the following criteria (1) to (3). The test was conducted so that the bending diameter R of the sample piece was 2.5 mm and 3.0 mm, and the results were tested to see if any of the following (1) to (3) was met.
(1) R = 2.5 mm, no cracks occurred after bending over 100,000 times (R = 2.5 mm, no cracks),
(2) A crack occurred when R = 2.5 mm and the number of bends was less than 100,000 times, but no crack occurred when R = 3.0 mm and the number of times of bending was 100,000 times or more (R = 3.0 mm, no crack);
(3) R = 3.0mm, cracks occurred after bending less than 100,000 times (R = 3.0mm cracks occurred)

According to Table 3, in Examples 1 to 7, no cracks occurred in the cover film when R = 2.5 mm or 3.0 mm and after bending 100,000 times or more, but in Comparative Examples 1 to 4, R = 3.0 mm. 0 mm, cracks occurred when the number of bends was less than 100,000 times. In Example 6, cracks occurred when R=2.5 mm and the number of bends was less than 100,000 times, but this is thought to be because the content of the rosin ester tackifying resin was small.

Comparative Examples 1 to 4 all have high 25°C storage modulus, and therefore are considered to have low bending resistance. In addition, since Comparative Example 2 had a high storage modulus as described above, it is considered that the bending resistance was low even though the rosin ester tackifier resin was contained.

1 First release sheet 2 Adhesive sheet (adhesive layer)
3 Second release sheet

Claims (3)

(meth)acrylic acid ester copolymer as the main component,
An isocyanate crosslinking agent,
Rosin ester tackifier resin,
Contains
The adhesive layer contains 5 parts by weight or more and 30 parts by weight or less of the rosin ester tackifying resin based on 100 parts by weight of the (meth)acrylic acid ester copolymer, and consists only of an adhesive layer containing a crosslinked adhesive composition. An adhesive sheet for an image display device,
The adhesive layer has a maximum value of tan δ (glass transition temperature) of −20° C. or less at 1 Hz,
The adhesive layer has a storage elastic modulus of 1.0 x 10 ⁵ Pa or less at 1 Hz and 25°C, and a storage elastic modulus of 4.6 x 10 ⁴ Pa or less at 1 Hz and -20°C of 5.4 x 10 ⁴ Pa. An adhesive sheet for an image display device, which is as follows. The adhesive sheet for an image display device according to claim 1, having a thickness of 5 to 100 μm. A peeling base sheet attached to at least one surface of the adhesive sheet for an image display device according to claim 1 or 2;
An adhesive sheet laminate for image display devices, comprising: