JP2021175796A - Double-sided adhesive tape - Google Patents

Abstract

To provide a double-sided adhesive tape that has excellent shock absorbency across a wide temperature range, in particular in a low temperature range.SOLUTION: This double-sided adhesive tape has an adhesive layer on both surface sides of a base material layer, where the storage modulus E' of the entire double-sided adhesive tape, when measured at a frequency of 1 Hz at -25°C to 120°C, is within the range of 1.0×105 Pa-1.0×108 Pa.SELECTED DRAWING: Figure 1

Description

The present invention relates to a double-sided adhesive tape.

A device with a display has a problem that the display screen is cracked when an impact is applied due to dropping or the like.

Therefore, for the purpose of absorbing such an impact, the adoption of a double-sided adhesive tape having excellent impact absorption has been proposed (for example, Patent Document 1).

However, in all of the wide temperature range, especially in the low temperature region, the conventional shock-absorbing adhesive tape has a problem that the shock-absorbing property is lowered.

Japanese Unexamined Patent Publication No. 2014-94575

An object of the present invention is to provide a double-sided adhesive tape having excellent shock absorption in all of a wide temperature range, particularly in a low temperature region.

The double-sided adhesive tape of the present invention
A double-sided adhesive tape having an adhesive layer on both sides of the base material layer.
The storage elastic modulus E'measured at a frequency of 1 Hz at −25 ° C. to 120 ° C. of the entire double-sided adhesive tape is in the range of ^{1.0 × 10 5} Pa to 1.0 × 10 ^{8 Pa.}

In one embodiment, the storage elastic modulus E'of the substrate layer measured at a frequency of 1 Hz at −25 ° C. to 120 ° C. is within the range of ^{1.0 × 10 5 Pa to 1.0 × 10 8 Pa.} Is.

In one embodiment, the maximum value of the storage elastic modulus G'of the pressure-sensitive adhesive layer measured at a frequency of 1 Hz at −25 ° C. to 120 ° C. is 1.0 × 10 ¹⁰ Pa or less.

In one embodiment, the pressure-sensitive adhesive layer has an adhesive force of 5 N / 20 mm or more on a SUS plate at a tensile speed of 300 mm / min and a 180-degree peel at 23 ° C. and 50% RH.

In one embodiment, the substrate layer comprises at least one polar functional group-containing polymer selected from condensation polymers and polyadditive polymers.

In one embodiment, the polar functional group-containing polymer is at least one selected from polyamide, polyurethane, and polyurea.

In one embodiment, the polar functional group-containing polymer has at least one selected from ether and ester bonds.

In one embodiment, the pressure-sensitive adhesive layer contains at least one selected from an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and a urethane-based pressure-sensitive adhesive.

In one embodiment, the adhesive tape of the present invention is a shock absorbing tape for a display.

According to the present invention, it is possible to provide a double-sided adhesive tape having excellent shock absorption in all of a wide temperature range, especially in a low temperature region.

FIG. 1 is a schematic cross-sectional view showing one embodiment of the double-sided adhesive tape of the present invention.

≪≪Double-sided adhesive tape≫≫
The double-sided adhesive tape according to the embodiment of the present invention is an adhesive tape having an adhesive layer on both sides of the base material layer. That is, as shown in FIG. 1, the double-sided adhesive tape 1000 according to the embodiment of the present invention is a double-sided adhesive tape having adhesive layers 200a and 200b on both sides of the base material layer 100.

The pressure-sensitive adhesive layer 200a and the pressure-sensitive adhesive layer 200b may be pressure-sensitive adhesive layers having the same composition as each other, or may be pressure-sensitive adhesive layers having different compositions.

The pressure-sensitive adhesive layer 200a and the pressure-sensitive adhesive layer 200b may have the same thickness or different thicknesses from each other.

The base material layer may be one layer or two or more layers. The base material layer is preferably one layer in that the effects of the present invention can be more exhibited.

The pressure-sensitive adhesive layer may be one layer or two or more layers. The pressure-sensitive adhesive layer is preferably one layer in that the effects of the present invention can be more exhibited.

The double-sided adhesive tape according to the embodiment of the present invention may have any suitable other layer other than the base material layer and the pressure-sensitive adhesive layer as long as the effects of the present invention are not impaired.

The double-sided adhesive tape according to the embodiment of the present invention may be provided with an arbitrary suitable release liner on the surface of the pressure-sensitive adhesive layer on the opposite side of the base material layer for protection until use or the like.

Examples of the release liner include a release liner in which the surface of a base material (liner base material) such as paper or plastic film is treated with silicone, and a polyolefin resin on the surface of a base material (liner base material) such as paper or plastic film. Examples include a laminated release liner. Examples of the plastic film as the liner base material include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, and polybutylene terephthalate film. Examples thereof include a polyurethane film and an ethylene-vinyl acetate copolymer film.

The thickness of the release liner is preferably 1 μm to 500 μm, more preferably 3 μm to 450 μm, further preferably 5 μm to 400 μm, and particularly preferably 10 μm to 300 μm.

It is preferable that at least one surface of the release liner is subjected to a mold release treatment. As the mold release treatment, any appropriate mold release treatment can be adopted as long as the effects of the present invention are not impaired.

The double-sided adhesive tape according to the embodiment of the present invention has a total thickness d of preferably 1 μm to 500 μm, more preferably 5 μm to 450 μm, further preferably 10 μm to 400 μm, and particularly preferably 15 μm to 350 μm. Most preferably, it is 30 μm to 300 μm. When the total thickness d of the double-sided adhesive tape according to the embodiment of the present invention is within the above range, the effect of the present invention can be further exhibited.

The double-sided adhesive tape according to the embodiment of the present invention has a storage elastic modulus E'measured at a frequency of 1 Hz at −25 ° C. to 120 ° C. of the entire double-sided adhesive tape of 1.0 × 10 ⁵ Pa to 1.0 × 10. It is within the range of ^{8 Pa.} The storage elastic modulus ^{E'is preferably in the range of 3.0 × 10 5} Pa to 1.0 × 10 ⁸ Pa, and more preferably in the range of 5 × 10 ⁵ Pa to 1.0 × 10 ^{8 Pa.} It is more preferably in ^{the range of 8.0 × 10 5} Pa to 9.9 × 10 ⁷ Pa, and particularly preferably in the range of 1.0 × 10 ⁶ Pa to 9.85 × 10 ^{7 Pa.} .. When the storage elastic modulus E'of the entire double-sided adhesive tape is within the above range, it is possible to provide a double-sided adhesive tape having excellent shock absorption in all of a wide temperature range, particularly in a low temperature region.

Double-sided pressure-sensitive adhesive tape according to an embodiment of the present invention, the whole double-sided adhesive tape, the storage modulus E 'measured at frequencies 1Hz at -25 ° C., it is preferably 1.0 × 10 8 ^Pa or less, more preferably It is 9.9 × 10 ⁷ Pa or less, more preferably 9.75 × 10 ⁷ Pa or less, and particularly preferably 9.6 × 10 ⁷ Pa or less. The lower limit of the storage modulus E 'measured at frequencies 1Hz in the -25 ° C. is preferably 5.0 × ¹⁰ 6 Pa or more. If the storage elastic modulus E'measured at a frequency of 1 Hz at the above-mentioned -25 ° C. of the entire double-sided adhesive tape is within the above range, the double-sided adhesive tape is more excellent in shock absorption in all of the wide temperature range, especially in the low temperature region. Tape can be provided.

Double-sided pressure-sensitive adhesive tape according to an embodiment of the present invention, the whole double-sided adhesive tape, the storage modulus E 'measured at frequencies 1Hz at 23 ° C., it is preferably 1.0 × 10 8 ^Pa or less, more preferably 3 It is 0.0 × 10 ⁶ Pa or less, more preferably 2.5 × 10 ⁶ Pa or less, and particularly preferably 2.3 × 10 ⁶ Pa or less. The lower limit of the storage modulus E 'measured at frequencies 1Hz at the 23 ° C. is preferably 5.0 × ¹⁰ 5 Pa or more. If the storage elastic modulus E'measured at the frequency of 1 Hz at the above 23 ° C. of the entire double-sided adhesive tape is within the above range, the double-sided adhesive tape is more excellent in shock absorption in all of the wide temperature range, especially in the low temperature region. Can be provided.

Double-sided pressure-sensitive adhesive tape according to an embodiment of the present invention, the whole double-sided adhesive tape, the storage modulus was measured at a frequency 1Hz at 80 ° C. E 'is, preferably 1.0 × 10 8 ^Pa or less, more preferably 3 It is 0.0 × 10 ⁶ Pa or less, more preferably 2.9 × 10 ⁶ Pa or less. The lower limit of the storage modulus E 'measured at frequencies 1Hz at the 80 ° C. is preferably 5.0 × ¹⁰ 5 Pa or more. If the storage elastic modulus E'measured at the frequency of 1 Hz at the above 80 ° C. of the entire double-sided adhesive tape is within the above range, the double-sided adhesive tape is more excellent in shock absorption in all of the wide temperature range, especially in the low temperature region. Can be provided.

In the double-sided adhesive tape according to the embodiment of the present invention, the ratio of the storage elastic modulus E'measured at a frequency of 1 Hz at −25 ° C. to the storage elastic modulus E'measured at a frequency of 1 Hz at 0 ° C. of the entire double-sided adhesive tape. (Storage modulus E'(-25 ° C.) / Storage modulus E'(80 ° C.)) is preferably 40.0 or less, more preferably 35.0 or less, still more preferably 30.0 or less. It is particularly preferably 18.0 or less. The lower limit of the above ratio (storage elastic modulus E'(-25 ° C.) / storage elastic modulus E'(80 ° C.)) is preferably 1.0 or more. The ratio of the storage elastic modulus E'measured at a frequency of 1 Hz at -25 ° C to the storage elastic modulus E'measured at a frequency of 1 Hz at 0 ° C for the entire double-sided adhesive tape (storage elastic modulus E'(-25 ° C) / When the storage elastic modulus E'(80 ° C.)) is within the above range, it is possible to provide a double-sided adhesive tape having better shock absorption in all of a wide temperature range, particularly in a low temperature region.

The double-sided adhesive tape according to the embodiment of the present invention has a storage elastic modulus E'of the base material layer measured at a frequency of 1 Hz at −25 ° C. to 120 ° C., preferably 1.0 × 10 ⁵ Pa to 1.0 × 10. ^{It is in the range of 8} Pa, more preferably in the range of 3.0 × 10 ⁵ Pa to 8.0 × 10 ⁷ Pa, and more preferably in the range of 5.0 × 10 ⁵ Pa to 5.0 × 10 ^{7 Pa. It is in the range of 1.0 × 10 6} Pa to 2.0 × 10 ⁷ Pa, and particularly preferably in the range of 1.0 × 10 6 Pa to 2.0 × 10 7 Pa. When the storage elastic modulus E'of the base material layer is within the above range, it is possible to provide a double-sided adhesive tape having better shock absorption in all of a wide temperature range, particularly in a low temperature region.

In the double-sided adhesive tape according to the embodiment of the present invention, the maximum value of the storage elastic modulus G'of the pressure-sensitive adhesive layer measured at a frequency of 1 Hz at −25 ° C. to 120 ° C. is preferably 1.0 × 10 ¹⁰ Pa or less. , More preferably in ^{the range of 1.0 × 10 2} Pa to 5.0 × 10 ⁹ Pa, and even more preferably in the range of 5.0 × 10 ² Pa to 1.0 × 10 ⁹ Pa, in particular. It is preferably in the range ^{of 1.0 × 10 3} Pa to 7.0 × 10 ^{8 Pa.} When the maximum value of the storage elastic modulus G'of the pressure-sensitive adhesive layer is within the above range, it is possible to provide a double-sided pressure-sensitive adhesive tape having better shock absorption in all of a wide temperature range, especially in a low temperature region. ..

The double-sided adhesive tape according to the embodiment of the present invention has an adhesive force of the pressure-sensitive adhesive layer at 23 ° C., 50% RH, a tensile speed of 300 mm / min, and a 180-degree peel, preferably 5 N / 20 mm or more. Yes, more preferably 5N / 20mm to 100N / 20mm, further preferably 5N / 20mm to 50N / 20mm, particularly preferably 5N / 20mm to 30N / 20mm, and most preferably 5N / 20mm to 20N /. It is 20 mm. If the adhesive force of the pressure-sensitive adhesive layer on the SUS plate at a tensile speed of 300 mm / min and 180-degree peel at 23 ° C. and 50% RH is within the above range, all of the wide temperature range, especially in the low temperature region. , A double-sided adhesive tape having better shock absorption can be provided.

≪Base material layer≫
The thickness of the base material layer is preferably 1 μm to 500 μm, more preferably 2 μm to 400 μm, further preferably 3 μm to 300 μm, and particularly preferably 5 μm to 200 μm. When the thickness of the base material layer is within the above range, it is possible to provide a double-sided adhesive tape having excellent shock absorption in all of a wide temperature range, particularly in a low temperature region.

As the material of the base material, any suitable material can be adopted as long as the effect of the present invention is not impaired. Such materials preferably include at least one polar functional group-containing polymer selected from condensation polymers and polyaddition polymers. That is, the substrate layer preferably contains at least one polar functional group-containing polymer selected from condensation polymers and polyaddition polymers.

The content ratio of at least one polar functional group-containing polymer selected from the condensation type polymer and the polyaddition type polymer in the base material layer is preferably 50% by weight to 100% by weight in that the effects of the present invention can be more exhibited. It is% by weight, more preferably 70% by weight to 100% by weight, further preferably 90% by weight to 100% by weight, particularly preferably 95% by weight to 100% by weight, and most preferably 98% by weight. ~ 100% by weight.

At least one polar functional group-containing polymer selected from the condensation polymer and the polyadditive polymer has a polar functional group such as a carbonyl group in the polymer main chain, and has a stronger intermolecular force than the radical polymerization polymer. Can work and have a network structure that does not depend on covalent bonds. A polymer having a large number of covalently bonded reticulated structures may have too high elasticity and a decrease in unevenness followability. In the condensed polymer and the heavy addition polymer having a network structure that does not depend on the covalent bond, the intermolecular force due to the polar functional group is weaker than the intermolecular force generated by the covalent bond, and the energy (work done by stress etc.) is smaller. It is easy to relieve stress due to deformation etc. In all cases, especially in the low temperature region, it is possible to provide a double-sided adhesive tape having better shock absorption.

The polar functional group-containing polymer is preferably at least one selected from polyamide, polyurethane, and polyurea. A polymer containing a hydrogen-bonding polar functional group (more accurately, a hydrogen-bonding polar functional group having a hydrogen donor property) such as polyamide, polyurethane, and polyurea has an intermolecular force of about 1/10 of that of a covalent bond. It is said that it can be cleaved by (the combination of hydrogen-bonding functional groups that generate intermolecular force changes), and it is effectively affected by the heat energy given at about room temperature and the energy generated by work such as stress generated by bending. Intermolecular force cleavage can occur. Therefore, it is possible to provide a double-sided adhesive tape having better shock absorption in all of a wide temperature range, especially in a low temperature region.

The base material layer more preferably contains a polar functional group-containing polymer which is a polyaddition polymer. In the polyaddition polymer, monomers having various functional groups can be adopted, the operation of converting the monomer to the polymer is easy, and various properties are imparted to the polyaddition polymer by taking advantage of these characteristics. It becomes possible.

The polar functional group-containing polymer, which is a polyaddition polymer, may have at least one selected from an ether bond and an ester bond. The ether bond can be introduced by adopting a monomer having an ether bond in obtaining the polyaddition polymer. The ester bond can be introduced by adopting a monomer having an ester bond when obtaining the polyaddition polymer. For example, when polyurethane is adopted as the polar functional group-containing polymer, examples of the polyurethane having an ether bond include ether-based polyurethane. Examples of polyurethanes having an ester bond include ester-based polyurethanes.

Examples of the ether-based polyurethane include urethane acrylate resin. The urethane acrylate resin is made of, for example, an oligomer obtained by polymerizing a precursor containing a polyether segment, a (meth) acrylic segment and a urethane segment in a situation where the molecular weight can be controlled, and then various additives are added thereto to form a resin. A coating composition for forming a film can be prepared, coated on a supporting base material, and crosslinked to obtain a urethane acrylate resin film on the supporting base material. More specifically, a compound containing a polyether polyol and an isocyanate group and a hydroxyalkyl (meth) acrylate, a compound containing an acrylic-modified polyether polyol and an isocyanate group, and the like are polymerized in advance to form a urethane acrylate oligomer. Additives are appropriately added to this to prepare a coating composition for forming a resin film, which can be applied and crosslinked on a supporting base material to obtain a urethane acrylate resin film on the supporting base material.

Examples of the polyether polyol include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol, and various derivatives thereof.

Examples of the hydroxyalkyl (meth) acrylate include hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate.

Examples of the isocyanate group-containing compound include a resin containing an isocyanate group, an oligomer containing an isocyanate group, and a monomer containing an isocyanate group. Examples of the isocyanate group-containing compound include methylenebis-4-cyclohexylisocyanate, trimethyllopropane adduct body of tolylene diisocyanate, trimethylolpropane adduct form of hexamethylene diisocyanate, trimethylol propane adduct form of isophorone diisocyanate, and tolylene diisocyanate. Isocyanurates, isocyanurates of hexamethylene diisocyanates, (poly) isocyanates such as biurets of hexamethylene diisocyanates, and blocks of these isocyanates.

Examples of the ester-based polyurethane include adipate-based (ester-based) polyurethane and polycaprolactone-based (ester-based) polyurethane.

If a monomer having an ether bond is used in obtaining the polyaddition polymer, the elasticity of the polyaddition polymer can be weakened and molecular flexibility can be imparted. If a monomer having an ester bond is used in obtaining the polyaddition polymer, rigidity can be imparted to the polyaddition polymer. Therefore, for example, when obtaining a polyadditive polymer, the elasticity and rigidity of the polyadditive polymer can be adjusted by appropriately combining a monomer having an ether bond and a monomer having an ester bond, or by adopting them alone. It is possible to provide a double-sided adhesive tape having better shock absorption in all of a wide temperature range, especially in a low temperature region.

When polyurethane (preferably ether-based polyurethane or ester-based polyurethane) is used as the polar functional group-containing polymer, a hydroxyl group-containing monomer may be used when obtaining polyurethane. When a hydroxyl group-containing monomer is used to obtain polyurethane, the isocyanate monomer used in the polyaddition reaction to obtain polyurethane reacts with the hydroxyl group-containing monomer to introduce a covalent network structure. Further, the hydroxyl group-containing monomer can be collectively applied as a raw material for polyurethane, and the labor of adding the raw material for polyurethane after preparation can be simplified.

As the polar functional group-containing polymer, polyurethane (preferably ether-based polyurethane or ester-based polyurethane) is preferable because the effects of the present invention can be more exhibited. Polyurethane is a polymer compound synthesized by subjecting a polyol (for example, diol) and a polyisocyanate (for example, diisocyanate) to a polyaddition reaction at a predetermined ratio.

Examples of polyurethanes (preferably ether-based polyurethanes and ester-based polyurethanes) include thermoplastic polyurethanes (TPUs) and thermosetting polyurethanes, which are more excellent in shock absorption in all of a wide temperature range, especially in a low temperature region. In addition, thermosetting polyurethane is preferable because it can provide a double-sided adhesive tape. The thermosetting polyurethane is preferably at least one selected from the group consisting of thermosetting ether-based polyurethanes and thermosetting ester-based polyurethanes, and more preferably, from the viewpoint that the effects of the present invention can be more exhibited. It is at least one selected from a thermosetting urethane acrylate resin and a thermosetting polycaprolactone-based (ester-based) polyurethane resin.

Examples of polyols that can be used in the synthesis of polyurethane include ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, and 1,6-hexanediol. , 1,8-octanediol, polyoxytetramethylene glycol, diethylene glycol, polyethylene glycol, polypropylene glycol and other diols; polyester which is a polycondensate of the above diol and dicarboxylic acid (for example, adipic acid, azelaic acid, sebacic acid). Polycols; carbonate diols such as polyalkylene carbonate diols; and the like. These may be only one kind or two or more kinds.

Examples of the polyisocyanate that can be used in the synthesis of polyurethane include aromatic, aliphatic, and alicyclic diisocyanates, and multimers (for example, dimers and trimers) of these diisocyanates. Examples of the diisocyanate include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, and 1,3-phenylenedi isocyanate. , 1,4-phenylenediocyanate, butane-1,4-diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4-diisocyanate, dicyclohexylmethane-4 , 4-Diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexane diisocyanate, m-tetramethylxylylene diisocyanate and the like. These may be only one kind or two or more kinds.

In addition to the polyol and polyisocyanate, other copolymerization components may be introduced into the polyurethane. Examples of other copolymerization components include monocarboxylic acids and dicarboxylic acids, trifunctional or higher polycarboxylic acids, hydroxycarboxylic acids, alkoxycarboxylic acids, and derivatives thereof. The other copolymerization component may be only one kind or two or more kinds. The content of the other copolymerization component in the polyurethane is preferably less than 30% by weight, more preferably less than 10% by weight, still more preferably less than 5% by weight.

≪Adhesive layer≫
The thickness of the pressure-sensitive adhesive layer is preferably 1 μm to 500 μm, more preferably 3 μm to 300 μm, further preferably 5 μm to 200 μm, and particularly preferably 10 μm to 120 μm. When the thickness of the pressure-sensitive adhesive layer is within the above range, it is possible to provide a double-sided pressure-sensitive adhesive tape having better shock absorption in all of a wide temperature range, particularly in a low temperature region.

The pressure-sensitive adhesive layer contains a base polymer. The base polymer may be only one kind or two or more kinds. The content ratio of the base polymer in the pressure-sensitive adhesive layer is preferably 30% by weight to 95% by weight, more preferably 40% by weight to 90% by weight, and further, in that the effects of the present invention can be more exhibited. It is preferably 50% by weight to 80% by weight.

As the base polymer, at least one selected from an acrylic polymer, a rubber polymer, a silicone polymer, and a urethane polymer is preferable because the effects of the present invention can be more exhibited. That is, the pressure-sensitive adhesive layer is preferably composed of an acrylic pressure-sensitive adhesive containing an acrylic polymer, a rubber-based pressure-sensitive adhesive containing a rubber-based polymer, a silicone-based pressure-sensitive adhesive containing a silicone-based polymer, and a urethane-based pressure-sensitive adhesive containing a urethane-based polymer. Includes at least one selected. In the following, as a typical example, an acrylic pressure-sensitive adhesive will be described in detail.

<Acrylic adhesive>
The acrylic pressure-sensitive adhesive contains an acrylic polymer as a base polymer. The acrylic pressure-sensitive adhesive may contain a pressure-imparting resin. The acrylic pressure-sensitive adhesive may contain a cross-linking agent.

When the acrylic pressure-sensitive adhesive contains an acrylic polymer, a tackifier resin, and a cross-linking agent, the content ratio of the total amount of the acrylic polymer, the pressure-imparting resin, and the cross-linking agent to the total amount of the acrylic pressure-sensitive adhesive is determined by the present invention. It is preferably 95% by weight or more, more preferably 97% by weight or more, and further preferably 99% by weight or more in that the effect can be more exhibited.

(Acrylic polymer)
As the acrylic polymer, a polymer having a monomer component containing an alkyl (meth) acrylate as a main monomer and further containing a submonomer having copolymerizability with the main monomer is preferable. Here, the main monomer means a component that accounts for more than 50% by weight of the total monomer component.

As the alkyl (meth) acrylate, for example, a compound represented by the following formula (1) can be preferably used.
CH ₂ = C (R ¹ ) COOR ² (1)

^{Here, R 1} in the above formula (1) is a hydrogen atom or a methyl group, and R ² is a chain alkyl group having 1 to 20 carbon atoms (hereinafter, such a range of carbon atoms is defined as “C1-”. It may be expressed as "20"). From the viewpoint of storage modulus of the pressure-sensitive adhesive layer, R ² is preferably a chain alkyl group of C1-14, more preferably a chain alkyl group having C2-10, more preferably of C4-8 It is a chain alkyl group. Here, the chain shape means to include a linear shape and a branched shape.

Examples of the alkyl (meth) acrylate in which R ² is a chain alkyl group of C1-20 include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and n-butyl. (Meta) acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, 2-ethylhexyl (meth) acrylate , Octyl (meth) acrylate, Isooctyl (meth) acrylate, Nonyl (meth) acrylate, Isononyl (meth) acrylate, Decyl (meth) acrylate, Isodecyl (meth) acrylate, Undecyl (meth) acrylate, Lauryl (meth) acrylate, Tridecyl (Meta) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate, nonadecil (meth) acrylate, ecocil ( Meta) acrylate and the like can be mentioned. These alkyl (meth) acrylates may be only one kind or two or more kinds.

Examples of the alkyl (meth) acrylate include n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) in that the effects of the present invention can be more exhibited.

The content ratio of the alkyl (meth) acrylate in all the monomer components used in the synthesis of the acrylic polymer is preferably 55% by weight or more, more preferably 60% by weight, in that the effect of the present invention can be more exhibited. It is more preferably 65% by weight or more, further preferably 70% by weight or more, particularly preferably 85% by weight or more, and most preferably 90% by weight or more. The upper limit of the content ratio of the alkyl (meth) acrylate is preferably 99.5% by weight or less, and more preferably 99% by weight or less. However, the acrylic polymer may be obtained by polymerizing substantially only an alkyl (meth) acrylate.

When R ² using the alkyl (meth) acrylate is a linear alkyl group of C4-8, alkyl R ² is a linear alkyl group of C4-8 among alkyl (meth) acrylates contained in the monomer components The proportion of the (meth) acrylate is preferably 50% by weight or more, more preferably 70% by weight or more, still more preferably 90% by weight or more, and particularly, in that the effect of the present invention can be more exhibited. It is preferably 95% by weight or more, and most preferably 99% by weight to 100% by weight.

As one embodiment (I) of the acrylic polymer, an acrylic polymer in which 80% by weight or more of all the monomer components are n-butyl acrylate (BA) can be mentioned. In this case, the content ratio of n-butyl acrylate (BA) in all the monomer components is preferably 82% by weight to 99% by weight, preferably 85% by weight or more, in that the effect of the present invention can be more exhibited. It is 98% by weight, more preferably 87% by weight to 97% by weight, particularly preferably 89% by weight to 96% by weight, and most preferably 91% by weight to 95% by weight.

Another embodiment (II) of the acrylic polymer is an acrylic polymer in which 50% by weight or more and less than 80% by weight of all monomer components is n-butyl acrylate (BA). In this case, the content ratio of n-butyl acrylate (BA) in all the monomer components is preferably 52% by weight to 80% by weight or less, more preferably 55% by weight, in that the effect of the present invention can be more exhibited. % To 80% by weight, more preferably 60% to 80% by weight, particularly preferably 63% to 80% by weight, and most preferably 65% to 80% by weight. In this embodiment, the total monomer component may further contain 2-ethylhexyl acrylate (2EHA) in a smaller proportion than n-butyl acrylate (BA).

Another embodiment (III) of the acrylic polymer is an acrylic polymer in which less than 50% by weight of the total monomer component is 2-ethylhexyl acrylate (2EHA). In this case, the content ratio of 2-ethylhexyl acrylate (2EHA) in all the monomer components is preferably more than 0% by weight and 48% by weight or less, more preferably 5 in that the effect of the present invention can be more exhibited. It is from% to 45% by weight, more preferably 10% to 43% by weight, particularly preferably 15% to 40% by weight, and most preferably 20% to 35% by weight. The total monomer component may further contain n-butyl acrylate (BA) in a larger proportion than 2-ethylhexyl acrylate (2EHA).

As another embodiment (IV) of the acrylic polymer, 50% by weight or more of all monomer components is n-butyl acrylate (BA), and less than 50% by weight of all monomer components is 2-ethylhexyl acrylate (2EHA). Acrylic polymer which is. In this case, the content ratio of n-butyl acrylate (BA) in all the monomer components is preferably 52% by weight to 80% by weight or less, more preferably 55% by weight, in that the effect of the present invention can be more exhibited. % To 80% by weight, more preferably 60% to 80% by weight, particularly preferably 63% to 80% by weight, and most preferably 65% to 80% by weight. Further, in this case, the content ratio of 2-ethylhexyl acrylate (2EHA) in all the monomer components is preferably more than 0% by weight and 48% by weight or less in that the effect of the present invention can be more exhibited, which is more preferable. Is 5% by weight to 45% by weight, more preferably 10% by weight to 43% by weight, particularly preferably 15% by weight to 40% by weight, and most preferably 20% by weight to 35% by weight.

The acrylic polymer may be copolymerized with another monomer (A) as long as the effects of the present invention are not impaired. The other monomer (A) may be only one type or two or more types. The other monomer (A) can be used, for example, for the purpose of adjusting the glass transition temperature (Tg) of the acrylic polymer, adjusting the adhesive performance, and the like. Examples of the other monomer (A) capable of improving the cohesiveness and heat resistance of the pressure-sensitive adhesive include a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, a cyano group-containing monomer, vinyl esters, and an aromatic vinyl compound. Therefore, vinyl esters are preferable. Specific examples of vinyl esters include vinyl acetate (VAc), vinyl propionate, vinyl laurate, and the like, with vinyl acetate (VAc) being preferred.

The content ratio of the other monomer (A) in all the monomer components is preferably 0.001% by weight to 40% by weight, more preferably 0.01% by weight to 40% by weight, still more preferably 0.1. It is from% by weight to 20% by weight, particularly preferably 0.5% by weight to 10% by weight, and most preferably 1% by weight to 5% by weight.

The acrylic polymer may be copolymerized with another monomer (B) as long as the effects of the present invention are not impaired. The other monomer (B) may be only one type or two or more types. The other monomer (B) is another monomer that can introduce a functional group that can serve as a cross-linking base point into the acrylic polymer or contribute to the improvement of the adhesive force. For example, a hydroxyl group (OH group) -containing monomer, a carboxy group-containing monomer, and the like. Examples thereof include an acid anhydride group-containing monomer, an amide group-containing monomer, an amino group-containing monomer, an imide group-containing monomer, an epoxy group-containing monomer, (meth) acryloylmorpholine, and vinyl ethers.

One embodiment of the acrylic polymer is an acrylic polymer in which a carboxy group-containing monomer is copolymerized as another monomer (B). Examples of the carboxy group-containing monomer include acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. Can be mentioned. Among these, acrylic acid (AA) and methacrylic acid (MAA) are preferably mentioned as the carboxy group-containing monomer, and acrylic acid (AA) is more preferable, because the effects of the present invention can be more exhibited. be.

When a carboxy group-containing monomer is adopted as the other monomer (B), the content ratio of the other monomer (B) in all the monomer components is preferably 0.1% by weight to more in that the effect of the present invention can be more exhibited. It is 10% by weight, more preferably 0.2% by weight to 8% by weight, further preferably 0.5% by weight to 5% by weight, and particularly preferably 0.7% by weight to 4% by weight. Most preferably, it is 1% by weight to 3% by weight.

The acrylic polymer may be copolymerized with another monomer (C) as long as the effects of the present invention are not impaired. The other monomer (C) may be only one type or two or more types. Examples of the other monomer (C) include a hydroxyl group-containing monomer. Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate. ) Hydroxyalkyl (meth) acrylates such as acrylates; polypropylene glycol mono (meth) acrylates; N-hydroxyethyl (meth) acrylamides; and the like. Among these, as the hydroxyl group-containing monomer, hydroxyalkyl (meth) acrylate in which the alkyl group is linear with 2 to 4 carbon atoms is preferable because the effect of the present invention can be more exhibited. Examples thereof include 2-hydroxyethyl acrylate (HEA) and 4-hydroxybutyl acrylate (4HBA).

When a hydroxyl group-containing monomer is used as the other monomer (C), the content ratio of the other monomer (C) in all the monomer components is preferably 0.001% by weight to 10% by weight in that the effects of the present invention can be more exhibited. It is% by weight, more preferably 0.01% by weight to 5% by weight, further preferably 0.02% by weight to 2% by weight, and particularly preferably 0.03% by weight to 1% by weight. Most preferably, it is 0.04% by weight to 0.5% by weight.

The Tg of the base polymer can be, for example, −80 ° C. or higher in that the effects of the present invention can be more exhibited. The base polymer (preferably an acrylic polymer) is designed so that the Tg is preferably −15 ° C. or lower from the viewpoint of increasing the deformability of the pressure-sensitive adhesive layer in the shearing direction. In some embodiments, the Tg of the base polymer is, for example, preferably −25 ° C. or lower, more preferably −40 ° C. or lower, and even more preferably −50 ° C. or lower. The Tg of the base polymer is designed so that, for example, the Tg is preferably −70 ° C. or higher (more preferably −65 ° C. or higher, further preferably −60 ° C. or higher) from the viewpoint of enhancing cohesiveness and shape restoration. Has been done.

The Tg of the base polymer is derived from the Fox formula based on the Tg of the homopolymer of each monomer constituting the base polymer and the weight fraction (copolymerization ratio based on the weight) of the monomer. The required value. As shown below, the Fox formula is a relational expression between the Tg of the copolymer and the glass transition temperature Tgi of the homopolymer in which each of the monomers constituting the copolymer is homopolymerized.
1 / Tg = Σ (Wi / Tgi)

In the Fox formula, Tg is the glass transition temperature (unit: K) of the copolymer, Wi is the weight fraction of the monomer i in the copolymer (copolymerization ratio based on the weight), and Tgi is the homopolymer of the monomer i. Represents the glass transition temperature (unit: K) of. As the Tg of the homopolymer, the value described in the publicly known material shall be adopted.

As the Tg of the homopolymer, for example, the following values can be specifically used.
2-Ethylhexyl acrylate-70 ° C
n-Butyl acrylate -55 ° C
Acrylic acid 106 ℃
2-Hydroxyethyl acrylate -15 ° C
4-Hydroxybutyl acrylate-40 ° C

For Tg of homopolymers other than those exemplified above, the numerical values described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) can be used. When a plurality of numerical values are described in the above "Polymer Handbook", the conventional value is adopted. For monomers not described in the above "Polymer Handbook", the catalog values of the monomer manufacturing companies are adopted. As the Tg of the homopolymer of the monomer which is not described in the above "Polymer Handbook" and the catalog value of the monomer manufacturing company is not provided, the value obtained by the measuring method described in JP-A-2007-51271 is used. do.

As a method for obtaining the acrylic polymer, for example, various polymerization methods known as synthetic methods for the acrylic polymer, such as a solution polymerization method, an emulsion polymerization method, a massive polymerization method, and a suspension polymerization method, are appropriately adopted. Can be done. Among these polymerization methods, the solution polymerization method can be preferably used. As a monomer supply method for solution polymerization, a batch charging method, a continuous supply (dropping) method, a divided feeding (dropping) method, or the like in which the entire amount of the monomer components is supplied at one time can be appropriately adopted. The polymerization temperature can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, etc., and is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, still more preferably 40 ° C. The above is preferably 170 ° C. or lower, more preferably 160 ° C. or lower, and further preferably 140 ° C. or lower. As a method for obtaining an acrylic polymer, photopolymerization performed by irradiating light such as UV (typically performed in the presence of a photopolymerization initiator) or radiation such as β-rays and γ-rays is irradiated. Active energy ray irradiation polymerization such as radiation polymerization may be adopted.

The solvent (polymerization solvent) used for solution polymerization can be appropriately selected from any suitable organic solvent. Examples thereof include aromatic compounds such as toluene (typically aromatic hydrocarbons), acetate esters such as ethyl acetate, and aliphatic or alicyclic hydrocarbons such as hexane and cyclohexane.

The initiator (polymerization initiator) used for the polymerization can be appropriately selected from any suitable polymerization initiator depending on the type of the polymerization method. The polymerization initiator may be only one kind or two or more kinds. Examples of such a polymerization initiator include an azo-based polymerization initiator such as 2,2'-azobisisobutyronitrile (AIBN); a persulfate such as potassium persulfate; benzoyl peroxide, hydrogen peroxide and the like. Peroxide-based initiators; substituted ethane-based initiators such as phenyl-substituted ethane; aromatic carbonyl compounds; and the like. Another example of the polymerization initiator is a redox-based initiator that is a combination of a peroxide and a reducing agent.

The amount of the polymerization initiator used is preferably 0.005 parts by weight to 1 part by weight, more preferably 0.01 parts by weight to 1 part by weight, based on 100 parts by weight of all the monomer components.

Mw of the acrylic polymer is preferably ^{10 × 10 4 ~500 × 10 4} , more preferably from ^{10 × 10 4 ~150 × 10 4} , more preferably be 20 × ^{10 4} ~75 × ¹⁰ 4 , Particularly preferably 35 × 10 ^{4 to} 65 × 10 ⁴ . Here, Mw refers to a standard polystyrene-equivalent value obtained by GPC (gel permeation chromatography). As the GPC apparatus, for example, a model name "HLC-8320GPC" (column: TSKgel GMH-H (S), manufactured by Tosoh Corporation) can be used.

(Adhesive-imparting resin)
The acrylic pressure-sensitive adhesive may include a pressure-imparting resin in that the effects of the present invention can be more exhibited. Examples of the tackifying resin include a rosin-based tackifying resin, a terpene-based tackifying resin, a hydrocarbon-based tackifying resin, an epoxy-based tackifying resin, a polyamide-based tackling resin, an elastomer-based tackifying resin, and a phenol-based tackifying resin. , Ketone-based adhesive-imparting resin and the like. The tackifier resin may be of only one type or of two or more types.

The amount of the tackifier resin used is preferably 5 parts by weight to 70 parts by weight, more preferably 10 parts by weight to 60 parts by weight, based on 100 parts by weight of the base polymer, in that the effects of the present invention can be more exhibited. It is, more preferably 15 parts by weight to 50 parts by weight, further preferably 20 parts by weight to 45 parts by weight, and particularly preferably 25 parts by weight to 40 parts by weight.

The tackifier resin preferably contains a tackifier resin TL having a softening point of less than 105 ° C. in that the effects of the present invention can be more exhibited. The tackifier resin TL can effectively contribute to the improvement of the deformability of the pressure-sensitive adhesive layer in the surface direction (shearing direction). From the viewpoint of obtaining a higher deformability improving effect, the softening point of the tackifier resin used as the tackifier resin TL is preferably 50 ° C. to 103 ° C., more preferably 60 ° C. to 100 ° C., and further preferably. It is 65 ° C. to 95 ° C., particularly preferably 70 ° C. to 90 ° C., and most preferably 75 ° C. to 85 ° C.

The softening point of the tackifier resin is defined as a value measured based on the softening point test method (ring ball method) specified in JIS K5902 and JIS K2207. Specifically, the sample is melted as quickly as possible at the lowest possible temperature, and the ring placed on a flat metal plate is carefully filled to prevent bubbles. After cooling, use a slightly heated sword to cut off the raised part from the flat surface including the upper end of the ring. Next, a support (ring stand) is placed in a glass container (heating bath) having a diameter of 85 mm or more and a height of 127 mm or more, and glycerin is poured until the depth becomes 90 mm or more. Next, the steel ball (diameter 9.5 mm, weight 3.5 g) and the ring filled with the sample are immersed in glycerin without contacting each other, and the temperature of glycerin is kept at 20 ° C. plus or minus 5 ° C. for 15 minutes. .. Next, a steel ball is placed in the center of the surface of the sample in the ring and placed in place on the support. Next, the distance from the upper end of the ring to the glycerin surface is kept at 50 mm, a thermometer is placed, the center of the mercury bulb of the thermometer is set to the same height as the center of the ring, and the container is heated. The flame of the Bunsen burner used for heating should be between the center and the edge of the bottom of the container to equalize the heating. The rate at which the bath temperature rises after reaching 40 ° C. after the start of heating must be 5.0 plus or minus 0.5 ° C. per minute. The temperature at which the sample gradually softens and flows down from the ring and finally comes into contact with the bottom plate is read, and this is used as the softening point. Two or more softening points are measured at the same time, and the average value is adopted.

The amount of the tackifier resin TL used is preferably 5 parts by weight to 50 parts by weight, more preferably 10 parts by weight, based on 100 parts by weight of the base polymer, in that the effects of the present invention can be more exhibited. It is 45 parts by weight, more preferably 15 parts by weight to 40 parts by weight, particularly preferably 20 parts by weight to 35 parts by weight, and most preferably 25 parts by weight to 32 parts by weight.

As the tackifier resin TL, one or more of the tackifier resins exemplified above, which are appropriately selected from those having a softening point of less than 105 ° C., can be adopted. The tackifier resin TL preferably contains a rosin-based resin.

Examples of the rosin-based resin that can be preferably used as the tackifier resin TL include rosin esters such as unmodified rosin ester and modified rosin ester. Examples of the modified rosin ester include hydrogenated rosin ester.

The tackifier resin TL preferably contains a hydrogenated rosin ester in that the effects of the present invention can be more exhibited. The hydrogenated rosin ester preferably has a softening point of less than 105 ° C., more preferably 50 ° C. to 100 ° C., and even more preferably 60 ° C. to 90 ° C. in that the effects of the present invention can be more exhibited. It is particularly preferably 70 ° C. to 85 ° C., and most preferably 75 ° C. to 85 ° C.

The tackifier resin TL may contain a non-hydrogenated rosin ester. Here, the non-hydrogenated rosin ester is a concept that comprehensively refers to the above-mentioned rosin esters other than the hydrogenated rosin ester. Examples of the non-hydrogenated rosin ester include unmodified rosin ester, disproportionated rosin ester, and polymerized rosin ester.

As the non-hydrogenated rosin ester, the softening point is preferably less than 105 ° C., more preferably 50 ° C. to 100 ° C., still more preferably 60 ° C. to 90 ° C. in that the effect of the present invention can be more exhibited. ° C., particularly preferably 70 ° C. to 85 ° C., and most preferably 75 ° C. to 85 ° C.

The tackifier resin TL may contain other tackifier resins in addition to the rosin-based resin. As the other tackifier resin, one or more of the tackifier resins exemplified above, which are appropriately selected from those having a softening point of less than 105 ° C., may be adopted. The tackifier resin TL may contain, for example, a rosin-based resin and a terpene resin.

The content ratio of the rosin-based resin in the entire tackifier resin TL is preferably more than 50% by weight, more preferably 55% by weight to 100% by weight, still more preferably, in that the effect of the present invention can be more exhibited. Is 60% by weight to 99% by weight, particularly preferably 65% by weight to 97% by weight, and most preferably 75% by weight to 97% by weight.

The tackifier resin may contain a combination of the tackifier resin TL and the tackifier resin TH having a softening point of 105 ° C. or higher (preferably 105 ° C. to 170 ° C.) in that the effects of the present invention can be more exhibited. good.

As the tackifier resin TH, one or more of the tackifier resins exemplified above, which are appropriately selected from those having a softening point of 105 ° C. or higher, can be adopted. The tackifier resin TH may include at least one selected from rosin-based tackifier resins (eg, rosin esters) and terpene-based tackifier resins (eg, terpene phenolic resins).

(Crosslinking agent)
The acrylic pressure-sensitive adhesive may contain a cross-linking agent. The cross-linking agent may be only one kind or two or more kinds. By using a cross-linking agent, an appropriate cohesive force can be imparted to the acrylic pressure-sensitive adhesive. Crosslinkers can also help control shift and return distances in retention tests. An acrylic pressure-sensitive adhesive containing a cross-linking agent can be obtained, for example, by forming a pressure-sensitive adhesive layer using a pressure-sensitive adhesive composition containing the cross-linking agent. The cross-linking agent may be contained in the acrylic pressure-sensitive adhesive in a form after the cross-linking reaction, a form before the cross-linking reaction, a form partially cross-linked, an intermediate or a composite form thereof, and the like. The cross-linking agent is typically contained in the acrylic pressure-sensitive adhesive exclusively in the form after the cross-linking reaction.

The amount of the cross-linking agent used is preferably 0.005 parts by weight to 10 parts by weight, more preferably 0.01 parts by weight, based on 100 parts by weight of the base polymer, in that the effects of the present invention can be more exhibited. It is ~ 7 parts by weight, more preferably 0.05 parts by weight to 5 parts by weight, particularly preferably 0.1 parts by weight to 4 parts by weight, and most preferably 1 part by weight to 3 parts by weight.

Examples of the cross-linking agent include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, silicone-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, silane-based cross-linking agents, alkyl etherified melamine-based cross-linking agents, and metal chelate-based cross-linking agents. , Crosslinking agents such as peroxides, etc. are preferable, and isocyanate-based cross-linking agents and epoxy-based cross-linking agents are preferable, and isocyanate-based cross-linking agents are more preferable, in that the effects of the present invention can be more exhibited. ..

As the isocyanate-based cross-linking agent, a compound having two or more isocyanate groups (including an isocyanate regenerated functional group in which the isocyanate group is temporarily protected by a blocking agent or quantification) in one molecule can be used. Examples of the isocyanate-based cross-linking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate; aliphatic isocyanates such as isophorone diisocyanate; and aliphatic isocyanates such as hexamethylene diisocyanate.

More specifically, as the isocyanate-based cross-linking agent, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; 2 , 4-Tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, polymethylenepolyphenyl isocyanate and other aromatic diisocyanates; trimethylolpropane / tolylene diisocyanate trimer adduct (eg, manufactured by Toso Co., Ltd., Product name: Coronate L), Trimethylol propane / hexamethylene diisocyanate trimeric adduct (for example, manufactured by Toso Co., Ltd., trade name: Coronate HL), isocyanurate of hexamethylene diisocyanate (for example, manufactured by Toso Co., Ltd., product name: Isocyanate adduct such as Coronate HX); Trimethylol propane adduct of xylylene diisocyanate (for example, manufactured by Mitsui Chemicals, trade name: Takenate D110N), Trimethylol propane adduct of xylylene diisocyanate (eg, manufactured by Mitsui Chemicals Co., Ltd., Product name: Takenate D120N), Trimethylol propane adduct of isophorone diisocyanate (for example, manufactured by Mitsui Chemicals, trade name: Takenate D140N), Trimethylol propane adduct of hexamethylene diisocyanate (for example, manufactured by Mitsui Chemicals, trade name: Takenate D160N); polyether polyisocyanates, polyester polyisocyanates, and additions of these to various polyols; polyisocyanates polyfunctionalized with isocyanurate bonds, burette bonds, allophanate bonds, and the like; and the like. Among these, aromatic isocyanates and alicyclic isocyanates are preferable because they can achieve both deformability and cohesive force in a well-balanced manner.

The amount of the isocyanate-based cross-linking agent used is preferably 0.005 parts by weight to 10 parts by weight, more preferably 0.01 parts by weight, based on 100 parts by weight of the base polymer, in that the effects of the present invention can be more exhibited. It is 7 parts by weight to 7 parts by weight, more preferably 0.05 parts by weight to 5 parts by weight, particularly preferably 0.1 parts by weight to 4 parts by weight, and most preferably 1 part to 3 parts by weight. be.

When the monomer component constituting the acrylic polymer contains a hydroxyl group-containing monomer, the weight ratio of the isocyanate-based cross-linking agent / hydroxyl group-containing monomer is preferably more than 20 and less than 50 in that the effect of the present invention can be more exhibited. It is more preferably 22 to 45, further preferably 25 to 40, particularly preferably 27 to 40, and most preferably 30 to 35.

When the acrylic pressure-sensitive adhesive contains a pressure-sensitive adhesive resin TL having a softening point of 105 ° C. or lower, the weight ratio of the pressure-sensitive adhesive resin TL / isocyanate-based cross-linking agent preferably exceeds 2 in that the effects of the present invention can be more exhibited. It is less than 15, more preferably 5 to 13, still more preferably 7 to 12, and particularly preferably 7 to 11.

As the epoxy-based cross-linking agent, a polyfunctional epoxy compound having two or more epoxy groups in one molecule can be used. Examples of the epoxy-based cross-linking agent include N, N, N', N'-tetraglycidyl-m-xylene diamine, diglycidyl aniline, 1,3-bis (N, N-diglycidyl aminomethyl) cyclohexane, 1, 6-Hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, penta Ellisritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipate diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris (2-hydroxyethyl) isocyanurate, Examples thereof include resorcin diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. Examples of commercially available epoxy-based cross-linking agents include trade names "Tetrad C" and "Tetrad X" manufactured by Mitsubishi Gas Chemical Company.

The amount of the epoxy-based cross-linking agent used is preferably 0.005 parts by weight to 10 parts by weight, more preferably 0.01 parts by weight, based on 100 parts by weight of the base polymer, in that the effects of the present invention can be more exhibited. It is 5 parts by weight to 5 parts by weight, more preferably 0.015 parts by weight to 1 part by weight, further preferably 0.015 parts by weight to 0.5 parts by weight, and particularly preferably 0.015 parts by weight to 1 part by weight. It is 0.3 parts by weight, most preferably 0.15 parts by weight to 0.3 parts by weight.

(Other ingredients)
Acrylic adhesives include colorants (pigments, dyes, etc.), leveling agents, cross-linking aids, plasticizers, softeners, fillers, antistatic agents, anti-aging agents, UV absorbers, and antioxidants, as needed. It may contain various additives that are common in the field of pressure-sensitive adhesives, such as agents and light stabilizers. As for such various additives, conventionally known ones can be used by a conventional method.

When a colorant (pigment, dye, etc.) is used as the other component, the amount used is preferably 0.001 part by weight to 10 parts by weight, more preferably 0, based on 100 parts by weight of the base polymer. It is 0.01 parts by weight to 5 parts by weight, more preferably 0.05 parts by weight to 1 part by weight, and particularly preferably 0.1 parts by weight to 1 part by weight.

≪≪Use≫≫
The double-sided adhesive tape according to the embodiment of the present invention has excellent shock absorption in all of a wide temperature range, especially in a low temperature region. Taking advantage of this feature, the double-sided adhesive tape according to the embodiment of the present invention can be used as, for example, a shock absorbing tape for a display.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited thereto. In the following description, "part" and "%" are based on weight unless otherwise specified.

<Measurement of storage elastic modulus E'of the entire double-sided adhesive tape>
Using RSA-G2 (TA Instruments Japan Co., Ltd.) as a dynamic viscoelasticity measuring device, a sample with a sheet width of 10 mm was placed on the measuring device tension jig at a measurement interval of 20 mm, and the measurement start temperature was reached. The measurement environment oven was changed. After confirming that the temperature in the measurement environment was stable, the temperature was raised at a temperature rise rate of 5 ° C./min from the lower limit of the temperature in the predetermined temperature range for measurement. The frequency at the time of measurement was 1 Hz, and tensile deformation was applied, and the amount of deformation strain was calculated as the storage elastic modulus E'while controlling the amount of deformation strain in the region where the sheet was not permanently deformed.

<Measurement of storage elastic modulus E'of the substrate layer>
Using RSA-G2 (TA Instruments Japan Co., Ltd.) as a dynamic viscoelasticity measuring device, a sample with a sheet width of 10 mm was placed on the measuring device tension jig at a measurement interval of 20 mm, and the measurement start temperature was reached. The measurement environment oven was changed. After confirming that the temperature in the measurement environment was stable, the temperature was raised at a temperature rise rate of 5 ° C./min from the lower limit of the temperature in the predetermined temperature range for measurement. The frequency at the time of measurement was 1 Hz, and tensile deformation was applied, and the amount of deformation strain was calculated as the storage elastic modulus E'while controlling the amount of deformation strain in the region where the sheet was not permanently deformed.

<Measurement of storage elastic modulus G'of the adhesive layer>
Using ARES-G2 (TA Instruments Japan Co., Ltd.) as a dynamic viscoelasticity measuring device, a sample with a sheet thickness of 1 mm to 2 mm is placed on a predetermined measuring device jig, and the measurement environment is set to the measurement start temperature. I changed the oven. After confirming that the temperature in the measurement environment was stable, the temperature was raised at a temperature rise rate of 5 ° C./min from the lower limit of the temperature in the predetermined temperature range for measurement. Shear deformation was applied at a frequency of 1 Hz at the time of measurement, and the amount of deformation strain was calculated as the storage elastic modulus G'while controlling the amount of deformation strain in a region where the sheet was not permanently deformed.

<Adhesive strength>
Adhesive strength refers to 180 degree peeling strength (180 degree peeling adhesive strength) with respect to a stainless steel sheet. For 180 degree peeling strength, a single-sided adhesive tape (trade name "No. 31B", manufactured by Nitto Denko Co., Ltd., total thickness 50 μm) was attached to the surface of one of the two adhesive layers of the adhesive sheet. After that, for the measurement sample obtained by cutting the adhesive sheet into a size of 20 mm in width and 100 mm in length, the adhesive surface of the above measurement sample was placed on the surface of a stainless steel plate (SUS304BA plate) at 2 kg in an environment of 23 ° C. and 50% RH. The roll was reciprocated once and crimped. After leaving this in the same environment for 30 minutes, using a universal tensile compression tester, the peel strength (N /) under the conditions of a tensile speed of 300 mm / min and a peeling angle of 180 degrees according to JIS Z 0237: 2000. 20 mm) was measured. As the universal tensile compression tester, the product name "Autograph AG-10G type tensile tester" manufactured by Shimadzu Corporation was used.

<Shock absorption>
Impact absorption is indicated by the pressure at which the iron ball is dropped. A double-sided adhesive tape cut to 70 mm x 70 mm with the center aligned is placed on a stainless steel plate (SUS plate: 10 mm x 150 mm x 150 mm), and a 70 mm x 70 mm pressure measuring film (manufactured by Fujifilm) with the center aligned on it. , Prescale (type MS)) was placed on it, and a stainless steel plate (SUS plate: 5 mm × 70 mm × 70 mm) was placed on the stainless steel plate (SUS plate: 5 mm × 70 mm × 70 mm), and the iron ball (96 g) was dropped from a height of 40 cm. Next, the pressure measuring film was taken out, the image was captured by the pressure image analyzer scanner GT-F740 (manufactured by Fujifilm), and the pressure was analyzed by the prescale pressure image analysis system FPD-8010J (manufactured by Fujifilm).

[Example 1]
In a reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, and a cooler, n-butyl acrylate (BA) as a monomer component: 68 parts, 2-ethylhexyl acrylate (2EHA): 29 parts, acrylic acid (AA). ): 3 parts, and 4-hydroxybutyl acrylate (4HBA): 0.04 parts, 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator: 0.07 parts, as a polymerization solvent. To obtain 151 parts of the acrylic polymer (A), solution polymerization was carried out at 65 ° C. for 5 hours and further at 80 ° C. for 2 hours to obtain a toluene solution of the acrylic polymer (A). The weight average molecular weight of this acrylic polymer (A) was 440,000.
Acrylic polymer (A) contained in the toluene solution: 100 parts, tackifier resin (manufactured by Harima Chemicals, hydrogenated rosin lycelin ester, trade name "Haritac SE10"): 30 parts, isocyanate-based cross-linking agent (Tosoh) Co., Ltd., trade name "Coronate L"): 3 parts were added to prepare an adhesive composition (A).
Two commercially available release liners (manufactured by Mitsubishi Chemical Corporation, trade name "Diafoil MRF # 50" (biaxially stretched polyester film-based release liner with single-sided release treatment layer, thickness 50 μm)) were prepared. The pressure-sensitive adhesive composition (A) was applied to one surface (peeling surface) of each release liner so that the thickness after drying was 50 μm, and dried at 120 ° C. for 5 minutes. In this way, the pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer and second pressure-sensitive adhesive layer) having a thickness of 50 μm, which is composed of the acrylic pressure-sensitive adhesive (A) corresponding to the pressure-sensitive adhesive composition (A), is formed in the above 2 It was formed on the peeling surface of each of the peeling liners.
As a base material layer, a thermosetting polyurethane resin film having a thickness of 100 μm (manufactured by Toray Industries, Inc., a polycaprolactone-based (ester-based) polyurethane resin film having a thickness of 100 μm (100% modulus = 1.8 MPa)) was prepared. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer formed on the above two release liners were bonded to the first and second surfaces of the base material layer. The release liner was left as it was on the pressure-sensitive adhesive layer and used to protect the surface (adhesive surface) of the pressure-sensitive adhesive layer. The obtained structure was passed once through a laminator (0.3 MPa, speed 0.5 m / min) at 80 ° C., and then aged in an oven at 50 ° C. for 3 days. In this way, the adhesive tape (1) was obtained.
The results are shown in Table 1.

[Example 2]
In a reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, and a cooler, n-butyl acrylate (BA) as a monomer component: 100 parts, vinyl acetate (VAc): 5 parts, acrylic acid (AA): 3 parts, 2-hydroxyethyl acrylate (HEA): 0.1 parts, 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator: 0.25 parts, and toluene as a polymerization solvent. : 200 parts were charged and solution-polymerized at 60 ° C. for 6 hours and further at 75 ° C. for 3 hours to obtain a toluene solution of the acrylic polymer (B). The weight average molecular weight of this acrylic polymer (B) was 550,000.
Acrylic polymer (B) contained in the toluene solution: 100 parts, tackifier resin (manufactured by Harima Kasei Co., Ltd., polymerized rosin ester, trade name "Haritac PCJ"): 10 parts, tackifier resin (manufactured by Harima Kasei Co., Ltd.) , Hydrogenated Rosing Riserin Ester, Product Name "Haritac SE10"): 10 parts, Adhesive-imparting Resin (Rika Hercules, Product Name "Harcolin D"): 5 Parts, Phenol-modified Rosin (Sumitomo Bakelite, Product Name " Sumilite PR12603N "): 15 parts and an isocyanate-based cross-linking agent (manufactured by Toso Co., Ltd., trade name" Coronate L "): 2 parts were added to prepare a pressure-sensitive adhesive composition (B).
Two commercially available release liners (manufactured by Mitsubishi Chemical Corporation, trade name "Diafoil MRF # 50" (biaxially stretched polyester film-based release liner with single-sided release treatment layer, thickness 50 μm)) were prepared. The pressure-sensitive adhesive composition (B) was applied to one surface (peeling surface) of each release liner so that the thickness after drying was 50 μm, and dried at 120 ° C. for 5 minutes. In this way, the pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer and second pressure-sensitive adhesive layer) having a thickness of 50 μm composed of the acrylic pressure-sensitive adhesive (B) corresponding to the pressure-sensitive adhesive composition (B) is formed in the above 2 It was formed on the peeling surface of each of the peeling liners.
As a base material layer, a thermosetting polyurethane resin film (manufactured by Toray Industries, Inc., a polycaprolactone-based (ester-based) polyurethane resin film having a thickness of 100 μm (100% modulus = 1.8 MPa)) was prepared. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer formed on the above two release liners were bonded to the first and second surfaces of the base material layer. The release liner was left as it was on the pressure-sensitive adhesive layer and used to protect the surface (adhesive surface) of the pressure-sensitive adhesive layer. The obtained structure was passed once through a laminator (0.3 MPa, speed 0.5 m / min) at 80 ° C., and then aged in an oven at 50 ° C. for 3 days. In this way, the adhesive tape (2) was obtained.
The results are shown in Table 1.

[Example 3]
In a reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, and a cooler, n-butyl acrylate (BA) as a monomer component: 100 parts, vinyl acetate (VAc): 3 parts, acrylic acid (AA): 2 parts, 2-hydroxyethyl acrylate (HEA): 0.2 parts, 2,2'-azobisisobutyronitrile (AIBN) as a polymerization initiator: 0.25 parts, and toluene as a polymerization solvent. : 200 parts were charged and solution-polymerized at 60 ° C. for 6 hours and further at 75 ° C. for 3 hours to obtain a toluene solution of the acrylic polymer (C). The weight average molecular weight of this acrylic polymer (C) was 600,000.
Acrylic polymer (C) contained in the toluene solution: 100 parts, tackifier resin (manufactured by Harima Kasei Co., Ltd., polymerized rosin ester, trade name "Haritac PCJ"): 10 parts, tackifier resin (manufactured by Harima Kasei Co., Ltd.) , Water-added rosing ricerin ester, trade name "Haritac SE10"): 10 parts, adhesive-imparting resin (manufactured by Rika Hercules, trade name "Harcoline D"): 5 parts, phenol-modified rosin (manufactured by Sumitomo Bakelite), trade name " Sumilite PR12603N "): 15 parts, isocyanate-based cross-linking agent (manufactured by Toso Co., Ltd., trade name" Coronate L "): 2 parts, black pigment (manufactured by Dainichi Seika Kogyo," NAF-5091 Black "): 0.2 parts In addition, the pressure-sensitive adhesive composition (C) was prepared.
Two commercially available release liners (manufactured by Mitsubishi Chemical Corporation, trade name "Diafoil MRF # 50" (biaxially stretched polyester film-based release liner with single-sided release treatment layer, thickness 50 μm)) were prepared. The pressure-sensitive adhesive composition (C) was applied to one surface (peeling surface) of each release liner so that the thickness after drying was 50 μm, and dried at 120 ° C. for 5 minutes. In this way, the pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer and second pressure-sensitive adhesive layer) having a thickness of 50 μm composed of the acrylic pressure-sensitive adhesive (C) corresponding to the pressure-sensitive adhesive composition (C) is formed in the above 2 It was formed on the peeling surface of each of the peeling liners.
Toluene: 50 parts, Polytetramethylene glycol (Mitsubishi Chemical Co., Ltd., PTMG2000): 330 parts, Hexamethylene diisocyanate: 50 parts, Hexamethylene diisocyanate isocyanurate-modified type (Mitsui Chemicals Co., Ltd., Takenate (registered trademark) D- 170N): 2 parts, dibutyltin laurate: 0.02 parts, hydroquinone monomethyl ether: 0.02 parts, 2-hydroxyethyl acrylate: 11 parts were mixed, held at 70 ° C. for 5 hours, and then diluted with toluene. A toluene solution having a solid content concentration of 60% by weight of oligomer A was obtained. Solid content concentration of the obtained oligomer (P) 60% by weight toluene solution: 100 parts, hindered phenolic antioxidant (manufactured by BASF Japan Ltd., IRGANOX1010): 5 parts, photopolymerization initiator (manufactured by BASF Japan Ltd.) , IRGACURE184): 1.5 parts were mixed and diluted with methyl ethyl ketone to obtain a coating composition (Q) for forming a resin film having a solid content concentration of 40% by weight.
A 50 μm-thick polyester film (manufactured by Toray Co., Ltd., trade name “Lumilar® R75X”) with a release layer is used as the support base material, and a resin film is used using a continuous coating device using a slot die coater. The forming coating composition (Q) is applied onto the release layer of the supporting base material by adjusting the discharge flow rate so that the thickness of the cured resin film is 100 μm, dried and cured, and the supporting group is formed. The resin film was peeled off from the material to obtain a thermosetting urethane acrylate resin film (R) (100% modulus = 2.0 MPa) having a thickness of 100 μm. The drying temperature was 80 ° C., and the curing conditions for ultraviolet rays (UV rays) were an irradiation output of 400 mW / cm ² and an integrated light intensity of 1200 mJ / cm ² .
The obtained thermosetting urethane acrylate resin film (R) is used as a base material layer, and the first pressure-sensitive adhesive layer and the first pressure-sensitive adhesive layer formed on the above two release liners are formed on the first and second surfaces of the base material layer. The second pressure-sensitive adhesive layer was laminated. The release liner was left as it was on the pressure-sensitive adhesive layer and used to protect the surface (adhesive surface) of the pressure-sensitive adhesive layer. The obtained structure was passed once through a laminator (0.3 MPa, speed 0.5 m / min) at 80 ° C., and then aged in an oven at 50 ° C. for 3 days. In this way, the adhesive tape (3) was obtained.
The results are shown in Table 1.

[Example 4]
An adhesive tape (4) was obtained in the same manner as in Example 3 except that the blending amount of the black pigment (“NAF-5091 Black” manufactured by Dainichiseika Kogyo Co., Ltd.) was changed to 0.6 parts.
The results are shown in Table 1.

[Example 5]
Same as Example 3 except that the base material layer was replaced with a thermosetting polyurethane resin film (manufactured by Toray Industries, Inc., 100 μm thick polycaprolactone-based (ester-based) polyurethane resin film (100% modulus = 1.8 MPa). To obtain an adhesive tape (5).
The results are shown in Table 1.

[Example 6]
An adhesive tape (6) was obtained in the same manner as in Example 5 except that the blending amount of the black pigment (“NAF-5091 Black” manufactured by Dainichiseika Kogyo Co., Ltd.) was changed to 0.6 parts.
The results are shown in Table 1.

[Comparative Example 1]
An adhesive tape (C1) was obtained in the same manner as in Example 1 except that a thermoplastic polyurethane resin film having a thickness of 100 μm (manufactured by Okura Industrial Co., Ltd., urethane elastomer film, trade name “Silklon”) was used as the base material layer. rice field.
The results are shown in Table 1.

[Comparative Example 2]
An adhesive tape (C2) was obtained in the same manner as in Example 2 except that a thermoplastic polyurethane resin film having a thickness of 100 μm (manufactured by Okura Industrial Co., Ltd., urethane elastomer film, trade name “Silklon”) was used as the base material layer. rice field.
The results are shown in Table 1.

[Comparative Example 3]
In a reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, and a cooler, n-butyl acrylate (BA) as a monomer component: 95 parts, acrylic acid (AA): 5 parts by weight, and as a polymerization initiator. 2,2'-Azobisisobutyronitrile (AIBN): 0.25 part and ethyl acetate as a polymerization solvent: 234 parts were charged and solution-polymerized at 65 ° C. for 9 hours to obtain an acrylic polymer (D). A solution of ethyl acetate was obtained. The weight average molecular weight of this acrylic polymer (D) was 600,000.
Acrylic polymer (D) contained in the toluene solution: 100 parts, tackifier resin (manufactured by Yasuhara Chemical Co., Ltd., terpenphenol resin, trade name "YS Polystar S145"): 30 parts, isocyanate-based cross-linking agent (manufactured by Toso Co., Ltd.) , Trade name "Coronate L"): 2 parts, Epoxy-based cross-linking agent (manufactured by Mitsubishi Gas Chemicals, trade name "Tetrad C"): 0.01 part was added to prepare a pressure-sensitive adhesive composition (D).
Two commercially available release liners (manufactured by Mitsubishi Chemical Corporation, trade name "Diafoil MRF # 50" (biaxially stretched polyester film-based release liner with single-sided release treatment layer, thickness 50 μm)) were prepared. The pressure-sensitive adhesive composition (D) was applied to one surface (peeling surface) of each release liner so that the thickness after drying was 50 μm, and dried at 120 ° C. for 5 minutes. In this way, the pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer and second pressure-sensitive adhesive layer) having a thickness of 50 μm composed of the acrylic pressure-sensitive adhesive (D) corresponding to the pressure-sensitive adhesive composition (D) is formed in the above 2 It was formed on the peeling surface of each of the peeling liners.
As a base material layer, a thermosetting polyurethane resin film having a thickness of 100 μm (manufactured by Toray Industries, Inc., a caprolactam-based (ester-based) polyurethane resin film having a thickness of 100 μm (100% modulus = 1.8 MPa)) was prepared. The first pressure-sensitive adhesive layer and the second pressure-sensitive adhesive layer formed on the above two release liners were bonded to the first and second surfaces of the base material layer. The release liner was left as it was on the pressure-sensitive adhesive layer and used to protect the surface (adhesive surface) of the pressure-sensitive adhesive layer. The obtained structure was passed once through a laminator (0.3 MPa, speed 0.5 m / min) at 80 ° C., and then aged in an oven at 50 ° C. for 3 days. In this way, an adhesive tape (C3) was obtained.
The results are shown in Table 1.

The double-sided adhesive tape according to the embodiment of the present invention has excellent shock absorption in all of a wide temperature range, especially in a low temperature region. Taking advantage of this feature, the double-sided adhesive tape according to the embodiment of the present invention can be used as, for example, a shock absorbing tape for a display.

1000 Double-sided adhesive tape 100 Base material layer 200a Adhesive layer 200b Adhesive layer

Claims (9)

A double-sided adhesive tape having an adhesive layer on both sides of the base material layer.
The storage elastic modulus E'measured at a frequency of 1 Hz at −25 ° C. to 120 ° C. of the entire double-sided adhesive tape is in the range of ^{1.0 × 10 5} Pa to 1.0 × 10 ^{8 Pa.}
Double-sided adhesive tape. According to claim 1, the storage elastic modulus E'of the base material layer measured at a frequency of 1 Hz at −25 ° C. to 120 ° C. is in the range of ^{1.0 × 10 5 Pa to 1.0 × 10 8 Pa.} The described double-sided adhesive tape. The double-sided adhesive tape according to claim 1 or 2, wherein the maximum value of the storage elastic modulus G'of the pressure-sensitive adhesive layer measured at a frequency of 1 Hz at −25 ° C. to 120 ° C. is 1.0 × 10 ^{10 Pa or less.} .. 7. Double-sided adhesive tape. The double-sided adhesive tape according to any one of claims 1 to 4, wherein the base material layer contains at least one polar functional group-containing polymer selected from a condensation polymer and a polyaddition polymer. The double-sided adhesive tape according to claim 5, wherein the polar functional group-containing polymer is at least one selected from polyamide, polyurethane, and polyurea. The double-sided adhesive tape according to claim 5 or 6, wherein the polar functional group-containing polymer has at least one selected from an ether bond and an ester bond. The double-sided adhesive tape according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive layer contains at least one selected from an acrylic pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, and a urethane-based pressure-sensitive adhesive. The double-sided adhesive tape according to any one of claims 1 to 8, which is a shock absorbing tape for a display.

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