JP7260999B2 - double sided adhesive tape - Google Patents

Description

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

Conventionally, double-sided adhesive tapes have been used to fix components in electronic devices (e.g., Patent Documents 1 and 2), and double-sided adhesive tapes have also been used to fix components in relatively large display panels such as televisions and monitors. there is Specifically, for example, each panel or film constituting the display panel is bonded together by double-sided adhesive tape. Such double-sided adhesive tapes are required to have appropriate flexibility to release stress from the viewpoint of impact resistance and obtaining excellent display performance. High-quality double-sided adhesive tape is often used.

JP 2009-242541 A JP 2009-258274 A

In recent years, so-called bezel-narrowing or bezel-less, in which the width of the peripheral portion of a display panel is narrowed, is progressing in order to increase the size or design the display panel. For this reason, from a structural point of view, it is difficult to fix by conventional fitting or screwing, and fixing by double-sided adhesive tape is expected.

However, in such a case, since the double-sided adhesive tape is used with a narrow width, the force for fixing the parts may not be sufficient. In particular, when bonding heavy parts such as large display panels, a large load is applied to the double-sided adhesive tape in a direction parallel to the adhesive interface, which may cause interlayer breakage of the foam base material or cause damage to the adherend. There is a problem that the double-sided adhesive tape is peeled off at the interface with. Conventional double-sided pressure-sensitive adhesive tapes that use a foam base material to enhance stress relaxation tend to suffer interlaminar breakage when a large load is applied, and it is difficult to achieve both stress relaxation and load holding power.

SUMMARY OF THE INVENTION An object of the present invention is to provide a double-sided pressure-sensitive adhesive tape having a foam base material and having high stress relaxation properties and yet having excellent holding power.

The present invention provides a double-sided pressure-sensitive adhesive tape having a foam substrate and pressure-sensitive adhesive layers containing an acrylic copolymer laminated on both sides of the foam substrate, wherein the breaking point is measured by the following shear tensile test. The double-sided adhesive tape has a strength of 12N or more.
(Shear tensile test)
Two SUS plates each having a size of 125 mm×50 mm and a thickness of 2 mm are attached to each other using a test piece of double-sided adhesive tape having a size of 25 mm×4 mm to prepare a sample for a shear tensile test. After fixing one SUS plate of the sample for the shear tensile test, pull the upper one of the other SUS plate in the shear direction at 0.1 mm / min under the condition of 23 ° C. When the test piece breaks Measure the force (strength at break) applied to the test piece.
The present invention will be described in detail below.

The present inventors investigated a double-sided pressure-sensitive adhesive tape having a foam substrate and pressure-sensitive adhesive layers containing an acrylic copolymer laminated on both sides of the foam substrate. The present inventors have found that by adjusting the strength at break measured by a specific shear tensile test of the double-sided pressure-sensitive adhesive tape within a specific range, the double-sided pressure-sensitive adhesive tape having a foam base material and high stress relaxation property can be retained. The present inventors have found that a double-sided pressure-sensitive adhesive tape having excellent strength can be obtained, and have completed the present invention.

The double-sided pressure-sensitive adhesive tape of the present invention has a foam substrate and pressure-sensitive adhesive layers containing an acrylic copolymer laminated on both sides of the foam substrate.
By having the foam base material, the double-sided pressure-sensitive adhesive tape of the present invention can have appropriate flexibility to release stress. This increases the impact resistance of the double-sided pressure-sensitive adhesive tape of the present invention. Further, when the double-sided pressure-sensitive adhesive tape of the present invention is used for fixing parts on a display panel, display unevenness on the display panel can be suppressed.

The double-sided pressure-sensitive adhesive tape of the present invention has a strength at break of 12 N or more as measured by the following shear tensile test.
(Shear tensile test)
Two SUS plates each having a size of 125 mm×50 mm and a thickness of 2 mm are attached to each other using a test piece of double-sided adhesive tape having a size of 25 mm×4 mm to prepare a sample for a shear tensile test. After fixing one SUS plate of the shear tensile test sample, pull one upper side of the other SUS plate in the shear direction at 0.1 mm / min under conditions of 23 ° C. When the test piece breaks Measure the force (strength at break) applied to the test piece.

The above shear tensile test will be described in detail.
FIG. 1 shows a schematic diagram showing a shear tensile test of a double-sided pressure-sensitive adhesive tape. First, a double-sided adhesive tape test piece 18 having a size of 25 mm×4 mm and two SUS plates 19 having a size of 125 mm×50 mm and a thickness of 2 mm are laminated as shown in FIG. After this laminate is crimped using a weight of 5 kg for 10 seconds, it is allowed to stand still for 24 hours, and a sample for a shear tensile test is prepared by laminating two SUS plates 19 via a test piece 18. . After fixing one of the SUS plates 19 of this shear tensile test sample, under the condition of 23° C., the upper one of the other SUS plate 19 is applied in the shear direction (the direction of the arrow in the figure) at 0.1 mm/min. The force applied to the test piece 18 when it is pulled and the test piece 18 breaks is measured (strength at break). Also, the displacement until the test piece 18 breaks is measured, and this is defined as the peeling stroke. Note that the breakage of the test piece 18 means that the foam substrate undergoes interlaminar failure.

If the breaking point strength is 12 N or more, even when a large load is applied to the double-sided adhesive tape in a direction parallel to the adhesive interface, the foam substrate will not be delaminated and the adherend will not be separated. It is possible to suppress peeling of the double-sided adhesive tape at the interface. From the viewpoint of further suppressing delamination of the foam base material and peeling of the double-sided adhesive tape at the interface with the adherend, the preferred lower limit of the strength at break is 15N, and the more preferred lower limit is 20N.
Although the upper limit of the strength at break is not particularly limited, a preferable upper limit is 60N, and a more preferable upper limit is 40N, from the viewpoint of not impairing the stress relaxation property of the double-sided pressure-sensitive adhesive tape.

The method of adjusting the strength at break within the above range is not particularly limited, but a method of adjusting the composition, density, 25% compressive strength, glass transition point (Tg), etc. of the foam substrate is preferable. A method of reducing the content of low molecular weight components in the acrylic copolymer, a method of reducing the molecular weight distribution (Mw/Mn) of the acrylic copolymer, and the like can also be used. These methods may be used alone or in combination of two or more.

The foam substrate may have a single-layer structure or a multi-layer structure.
The foam substrate is not particularly limited, and examples thereof include polyurethane foams, polyolefin foams, acrylic foams, and the like. Among them, polyurethane foam is preferable because it improves the stress relaxation property of the double-sided adhesive tape.

Examples of the polyurethane foam include a polyurethane foam made of a urethane resin composition containing polyisocyanate and polyol. Such a polyurethane foam can be produced by heat curing the urethane resin composition.
The polyisocyanate is not particularly limited, and includes aromatic polyisocyanate or aliphatic polyisocyanate used for general polyurethane foams. Among them, aromatic diisocyanates or aliphatic diisocyanates having two isocyanate groups in one molecule are preferable from the viewpoint of being able to increase the flexibility of the polyurethane foam.

When the polyisocyanate is the aromatic diisocyanate or the aliphatic diisocyanate, the degree of cross-linking of the polyurethane foam is not excessively increased, and the glass transition point (Tg) of the polyurethane foam is relatively low, so that the foam can be easily stretched. As a result, the strength at break of the double-faced pressure-sensitive adhesive tape is sufficiently increased without impairing the flexibility of the polyurethane foam, and both the stress relaxation property and holding power of the double-faced pressure-sensitive adhesive tape can be easily achieved.
Specific examples of the aromatic diisocyanate or aliphatic diisocyanate include 4,4′-diphenylmethane diisocyanate, tolylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,5-naphthalene diisocyanate, paraphenylene diisocyanate, 2,2 ,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, m-xylene diisocyanate, hexamethylene diisocyanate, hydrogenated MDI, isophorone diisocyanate and the like. 4,4′-diphenylmethane diisocyanate is also generally called “MDI” or “binuclear monomeric MDI”. Among them, 4,4'-diphenylmethane diisocyanate (MDI) is preferable because it is easy to obtain a polyurethane foam having excellent flexibility. These aromatic diisocyanates or aliphatic diisocyanates may be used alone or in combination of two or more.

The above polyisocyanate may have three or more isocyanate groups in one molecule. Examples of such polyisocyanates include polymeric MDI. Examples of the polyisocyanate further include urethane prepolymers having isocyanate groups. These polyisocyanates may be used alone or in combination of two or more.

The above polyol is not particularly limited, and includes polyols used for general polyurethane foams. Specific examples include polyether polyols, polyester polyols, polyether ester polyols, and the like. Moreover, trifunctional polyether polyol, glycerin, trimethylolpropane, etc. are mentioned as said polyol. These polyols may be used alone or in combination of two or more.
The polyether polyol is not particularly limited, and examples thereof include polypropylene glycol (PPG), diethylene glycol, 1,5-pentanediol, 1,6-hexamethylenediol and neopentyl glycol. The polyester polyol is not particularly limited, and a polyester polyol composed of a polyol component and an acid component can be used.

The polyol preferably contains a short-chain diol. By containing the short-chain diol in the polyol, the strength at break of the double-sided pressure-sensitive adhesive tape is sufficiently increased without impairing the flexibility of the polyurethane foam, and the stress relaxation and holding power of the double-sided pressure-sensitive adhesive tape are improved. are more likely to be compatible.
Examples of the short-chain diol include 1,5-pentanediol, 1,6-hexamethylenediol, neopentyl glycol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol and the like. These short-chain diols may be used alone or in combination of two or more. The diol preferably has 1 to 20 carbon atoms, more preferably 2 to 15 carbon atoms, still more preferably 3 to 10 carbon atoms, and more preferably 3 to 10 carbon atoms, from the viewpoint of achieving both high flexibility and strength in a substrate made of a polyurethane foam. more preferably 4 to 8, particularly preferably 5 to 6. Among them, 1,5-pentanediol or 1,6-hexamethylenediol is preferable because it is easy to obtain a high-strength polyurethane foam.

The weight average molecular weight of the polyol is not particularly limited, but the preferred lower limit is 500 and the preferred upper limit is 5,000. When the weight average molecular weight of the polyol is 500 or more, the polyurethane foam can have appropriate flexibility. If the weight average molecular weight of the polyol is 5000 or less, the strength at break will be sufficiently high. A more preferable lower limit of the weight average molecular weight of the polyol is 700, a more preferable upper limit is 2000, a still more preferable lower limit is 800, and a further preferable upper limit is 1500, from the viewpoint of easy control of the flexibility of the foam.
Incidentally, the weight average molecular weight of the polyol, for example, after preparing a tetrahydrofuran solution of the sample, using a GPC apparatus (for example, manufactured by Tosoh Corporation, product name "HLC-8220", column: TSKgelSuper HZM-N (4)). can be measured by

Although the isocyanate index of the polyisocyanate in the urethane resin composition is not particularly limited, the preferred lower limit is 70 and the preferred upper limit is 120.
The isocyanate index is an index related to the isocyanate equivalent in the reaction between an isocyanate and an active hydrogen-containing compound. When the isocyanate index is less than 70, the reactive groups such as hydroxyl groups are in excess of the isocyanate groups, and when the isocyanate index exceeds 120, the isocyanate groups are in excess of the reactive groups such as hydroxyl groups.
When the isocyanate index is 70 or more, cross-linking by the polyisocyanate is sufficient, and the polyurethane foam can have an appropriate density. When the isocyanate index is 120 or less, the degree of cross-linking of the polyurethane foam is not excessively increased, and the glass transition point (Tg) is relatively low, resulting in an easily stretchable foam. In either case, the stress relaxation property and holding power of the double-sided pressure-sensitive adhesive tape are likely to be compatible. From the viewpoint of further achieving both stress relaxation and holding power of the double-sided adhesive tape, the lower limit of the isocyanate index of the polyisocyanate is preferably 75, the upper limit is 110, the upper limit is 80, and the upper limit is 100. be.

Although the content of the polyisocyanate in the urethane resin composition is not particularly limited, the preferred lower limit is 5 parts by weight and the preferred upper limit is 15 parts by weight with respect to 100 parts by weight of the polyol. When the content of the polyisocyanate is 5 parts by weight or more, the polyisocyanate is sufficiently cross-linked, and the polyurethane foam can have an appropriate density. When the content of the polyisocyanate is 15 parts by weight or less, the degree of cross-linking of the polyurethane foam is not excessively increased, and the glass transition point (Tg) is relatively low, resulting in a foam that is easily stretched. In either case, the stress relaxation property and holding power of the double-sided pressure-sensitive adhesive tape are likely to be compatible. From the viewpoint of further achieving both stress relaxation and holding power of the double-sided adhesive tape, the content of the polyisocyanate in the urethane resin composition is preferably 7 parts by weight, and a more preferable upper limit is 7 parts by weight with respect to 100 parts by weight of the polyol. is 13 parts by weight.

The urethane resin composition may contain a catalyst, if necessary.
Examples of the catalyst include organic tin compounds, organic zinc compounds, organic nickel compounds, organic iron compounds, metal catalysts, tertiary amine catalysts, and organic acid salts. Among them, organic tin compounds are preferred. These catalysts may be used alone or in combination of two or more.
The amount of the catalyst added is not particularly limited, but the preferred lower limit is 0.05 parts by weight, the preferred upper limit is 5.0 parts by weight, and the more preferred upper limit is 4.0 parts by weight, per 100 parts by weight of the polyol.

Examples of the organic tin compounds include stannus octoate, dibutyltin diacetate, dibutyltin dilaurate, and the like. Examples of the organic zinc compound include zinc octylate. Examples of the organic nickel compound include nickel acetylacetoate and nickel diacetylacetoate. Examples of the organic iron compound include iron acetylacetoate. Examples of the metal catalyst include alkoxides and phenoxides of alkali metals such as sodium acetate or alkaline earth metals. Examples of the tertiary amine catalyst include triethylamine, triethylenediamine, N-methylmorpholinedimethylaminomethylphenol, imidazole, 1,8-diazabicyclo[5.4.0]undecene and the like.

The urethane resin composition may contain a foaming agent, if necessary.
Examples of the foaming agent include foaming agents used for general polyurethane foams. Specific examples include water, pentane, cyclopentane, hexane, cyclohexane, dichloromethane, carbon dioxide gas, and the like.
The amount of the foaming agent to be added is not particularly limited, and may be an appropriate amount. be.

The urethane resin composition may contain a foam stabilizer, if necessary.
Examples of the foam stabilizer include silicone-based foam stabilizers such as dimethylsiloxane, polyetherdimethylsiloxane, and phenylmethylsiloxane. Among them, polyetherdimethylsiloxane is preferred. Among polyetherdimethylsiloxanes, block copolymers of dimethylpolysiloxane and polyether are more preferred. These foam stabilizers may be used alone or in combination of two or more.
The amount of the foam stabilizer added is not particularly limited, but the preferred lower limit is 0.2 parts by weight, the preferred upper limit is 7 parts by weight, the more preferred lower limit is 0.4 parts by weight, and the more preferred upper limit is 100 parts by weight of the polyol. is 5 parts by weight.

The urethane resin composition may optionally contain additives commonly used in the production of polyurethane foams, such as ultraviolet absorbers, antioxidants, organic fillers, inorganic fillers, and colorants. good.

As a method for producing the polyurethane foam, for example, a urethane resin composition (liquid) that is mechanically mixed with air, nitrogen, etc. and foamed is applied to the surface of a release liner or a resin film, and the urethane resin composition is applied. A method of producing a foam by heating and curing (mechanical froth method). In addition, a method of reacting the polyisocyanate with the raw material for forming the polyurethane foam to generate a gas (chemical foaming method), and the like. Among them, the mechanical floss method is preferred. A polyurethane foam obtained by a mechanical froth method tends to have a higher density than a polyurethane foam obtained by a chemical foaming method, and tends to have a fine and uniform cell structure.

Examples of the polyolefin foams include foams made of resins such as polyethylene-based resins, polypropylene-based resins, and polybutadiene-based resins. Among these, polyethylene-based resins are preferable because flexible polyolefin foams can be easily obtained.

The density of the foam substrate is not particularly limited, but the preferred lower limit is 100 kg/m ³ and the preferred upper limit is 1000 kg/m ³ . When the density of the foam base material is 100 kg/m ³ or more, the strength at break is sufficiently high, and the dust resistance and water resistance of the foam base material are easily ensured. When the density of the foam base material is 1000 kg/m ³ or less, the foam base material can have appropriate flexibility. From the viewpoint of further improving the strength at break, dustproofness and waterproofness of the foam substrate, a more preferable lower limit of the density of the foam substrate is 110 kg/m ³ , and a more preferable lower limit is 120 kg/m ³ . . From the viewpoint of easy control of the flexibility of the foam substrate, the upper limit of the density of the foam substrate is more preferably 800 kg/m ³ , still more preferably 700 kg/m ³ , and particularly preferably 600 kg/m ³ . be.
Among others, when the foam substrate is the polyurethane foam, the density of the polyurethane foam has a preferable lower limit of 170 kg/m ³ , a preferable upper limit of 650 kg/m ³ , and a more preferable lower limit of 280 kg/m ³ . A more preferred upper limit is 500 kg/m ³ , and a still more preferred lower limit is 450 kg/m ³ .
The density can be measured using an electronic hydrometer (for example, "ED120T" manufactured by Mirage) in compliance with JIS K 6401 (when using polyurethane) and JIS K 6767 (when using polyethylene).

The 25% compressive strength of the foam base material is not particularly limited, but the preferred lower limit is 20 kPa and the preferred upper limit is 85 kPa. When the 25% compressive strength of the foam base material is 20 kPa or more, the strength at break is sufficiently high. When the 25% compressive strength of the foam base material is 85 kPa or less, the foam base material can have appropriate flexibility, and the double-sided adhesive tape can be satisfactorily crimped. From the viewpoint of improving the flexibility of the foam substrate and the pressure-bonding property of the double-sided adhesive tape, a more preferable lower limit of the 25% compressive strength of the foam substrate is 23 kPa, and a more preferable upper limit thereof is 50 kPa.
Among them, when the foam base material is the polyurethane foam, the preferable lower limit of the 25% compressive strength of the polyurethane foam is 25 kPa, the preferable upper limit is 40 kPa, and the more preferable lower limit is 30 kPa.
In addition, 25% compressive strength can be calculated|required by measuring based on JISK6254.

When the foam substrate is the polyurethane foam, at least the density of the polyurethane foam is 450 kg/m ³ or more and the 25% compressive strength of the polyurethane foam is 30 kPa or more. It is preferable to satisfy one. By adjusting in this way, the double-sided pressure-sensitive adhesive tape can exhibit high holding power.

The glass transition point of the foam substrate is not particularly limited, but the preferred lower limit is -30°C and the preferred upper limit is 30°C. When the glass transition point of the foam base material is -30°C or higher, the foam base material exhibits good low resilience and can relieve stress. If the glass transition point of the foam base material is 30° C. or less, the foam base material can have appropriate flexibility, and the foam base material can be stretched easily and the strength at break is sufficiently high. Become. A more preferable lower limit of the glass transition point of the foam substrate is -25°C, and a more preferable upper limit thereof is 20°C.
The glass transition point is measured using a viscoelasticity measuring device (for example, "Rheometrics Dynamic Analyze RDA-700" manufactured by Rheometrics Co., Ltd.) at a measurement temperature of -30 to 100 ° C., a temperature increase rate of 3 ° C./min, and a frequency of 1 Hz. It can be obtained under certain conditions.

The thickness of the foam base material is not particularly limited, but the preferred lower limit is 100 µm and the preferred upper limit is 2000 µm. When the thickness of the foam base material is 100 μm or more, the foam base material can have appropriate flexibility. If the thickness of the foam base material is 2000 μm or less, sufficient adhesion and fixation can be achieved with the double-sided adhesive tape. From the viewpoint that the pressure-sensitive adhesive tape can suppress excessive deformation in the shear direction, the lower limit of the thickness of the foam substrate is more preferably 150 μm, more preferably 200 μm, particularly preferably 250 μm, and particularly preferably 360 μm. From the viewpoint that the pressure-sensitive adhesive tape can reduce deformation in the shear direction, the upper limit of the thickness of the foam substrate is more preferably 1800 μm, more preferably 1600 μm, particularly preferably 1400 μm, and particularly preferably 1200 μm.
The thickness of the foam substrate can be measured using a dial thickness meter (eg, "ABS Digimatic Indicator" manufactured by Mitutoyo).

In another embodiment of the present invention, in the above double-sided tape, a resin sheet may be laminated on one or both surfaces of the foam substrate. That is, when a resin sheet is laminated on one or both surfaces of the foam base material, the foam base material and the resin sheet may be integrated. The double-sided pressure-sensitive adhesive tape of the present invention may further have a resin sheet integrated with the foam substrate. By using the resin sheet, it is possible to prevent the foam base material from being stretched and broken during handling, and to impart reworkability to the double-sided pressure-sensitive adhesive tape.
The resin constituting the resin sheet is not particularly limited. polyester, polycarbonate and the like. Among them, polyethylene-based resins, polypropylene-based resins, and polyester-based resins are preferable because of their excellent flexibility. Among polyester resins, polyethylene terephthalate is preferred. Among acrylic resins, methacrylic acid esters (methyl methacrylate, ethyl methacrylate, etc.) and acrylic acid esters (methyl acrylate, butyl acrylate, etc.) are used because they can be easily bonded to foam substrates. Block copolymers are preferred.

In the double-sided pressure-sensitive adhesive tape of the present invention, when resin sheets are laminated on both surfaces of the foam substrate, the tensile modulus of at least one of the resin sheets is preferably 0.1 MPa or more, more preferably 1 MPa or more. , more preferably 10 MPa or more, preferably 200 MPa or less, more preferably 150 MPa or less, still more preferably 100 MPa or less. When resin sheets are laminated on both surfaces of the foam base material, the reworkability of the double-sided pressure-sensitive adhesive tape can be enhanced if the bending resistance of at least one of the resin sheets is equal to or higher than the above lower limit. When resin sheets are laminated on both surfaces of the foam base material, if the bending resistance of at least one of the resin sheets is equal to or less than the above upper limit, the double-sided adhesive tape can be rolled into a double-sided tape. It is suitable because wrinkles are less likely to occur.

In addition, in this specification, the tensile modulus means the mechanical properties of the resin layer, and can be measured by a method according to JIS K 7161.
Specifically, for example, a test piece is produced by punching out a dumbbell from the above-mentioned resin sheet using a punching blade “tensile No. 1 dumbbell shape” manufactured by Kobunshi Keiki Co., Ltd., or the like. The obtained test piece is measured at a tensile speed of 100 mm/min using, for example, "Autograph AGS-X" manufactured by Shimadzu Corporation, and the test piece is broken.
The tensile modulus is calculated from the slope of the tensile strength between strains of 1-3%.

In the double-sided pressure-sensitive adhesive tape of the present invention, when a resin sheet is laminated on one or both surfaces of a foam base material and the foam base material and the resin sheet are integrated, the integration method is not particularly limited. For example, the foam base material and the resin sheet may be joined with an adhesive, or may be joined by thermocompression bonding. Moreover, the laminate of the foam base material and the resin sheet may be manufactured by integral molding. When bonding the foam base material and the resin sheet with an adhesive, the adhesive is not particularly limited, and an acrylic adhesive, a urethane adhesive, or the like can be used. Among others, it is preferable to integrate the foam base material and the resin sheet by integral molding.

When a resin sheet is laminated on one or both surfaces of the foam substrate, the thickness of the resin sheet is not particularly limited, but the preferred lower limit is 10 µm and the preferred upper limit is 100 µm. If the thickness of the resin sheet is 10 μm or more, the resin sheet is less likely to break even when the resin sheet is pulled, and reworkability after the double-sided pressure-sensitive adhesive tape is attached to an adherend can be improved. can. When the thickness of the resin sheet is 100 μm or less, it is possible to suppress deterioration of conformability to adherends. From the viewpoint of further improving the reworkability of the double-sided pressure-sensitive adhesive tape, the thickness of the resin sheet is more preferably 20 µm or more, and still more preferably 30 µm or more. From the viewpoint of further suppressing the deterioration of conformability to the adherend, the thickness is more preferably 80 μm or less, still more preferably 60 μm or less.

The resin sheet may be colored (for example, black). By coloring the resin sheet, the double-sided pressure-sensitive adhesive tape can be provided with a light-shielding property.
The method of coloring the resin sheet is not particularly limited, and examples include a method of kneading particles such as carbon black or titanium oxide or fine air bubbles into the resin constituting the resin sheet, and a method of applying ink to the surface of the resin sheet. methods and the like.

The double-sided pressure-sensitive adhesive tape of the present invention has pressure-sensitive adhesive layers containing an acrylic copolymer laminated on both sides of the foam substrate. The pressure-sensitive adhesive layers laminated on both sides of the foam substrate may have the same composition, or may have different compositions.

The acrylic copolymer is obtained by copolymerizing a monomer mixture.
In order to obtain the acrylic copolymer by copolymerizing the monomer mixture, the monomer mixture is subjected to a radical reaction in the presence of a polymerization initiator. As a method of radically reacting the monomer mixture, that is, a polymerization method, a conventionally known method is used, and examples thereof include solution polymerization (boiling point polymerization or constant temperature polymerization), emulsion polymerization, suspension polymerization, bulk polymerization, and the like. Examples of the reaction method for radically reacting the monomer mixture include living radical polymerization and free radical polymerization. Among them, living radical polymerization is preferred. That is, the acrylic copolymer is preferably an acrylic copolymer obtained by living radical polymerization.

Living radical polymerization is polymerization in which molecular chains grow without being hindered by side reactions such as termination reactions or chain transfer reactions. In the living radical polymerization, the reaction proceeds without deactivating the propagating terminal radical and without generating new radical species during the reaction. In the middle of the reaction, all molecular chains are uniformly polymerized while reacting with the monomer, and the composition of all molecular chains approaches uniformity.
Therefore, according to living radical polymerization, a copolymer having a more uniform molecular weight and composition can be obtained as compared with free radical polymerization, and the generation of low molecular weight components can be suppressed. power increases. This makes it easier to achieve both stress relaxation and holding power of the double-sided adhesive tape.

On the other hand, in free-radical polymerization, radical species are continuously generated during the reaction and added to the monomer to proceed the polymerization. Therefore, in the free radical polymerization, a molecular chain is formed by inactivation of the growing terminal radical during the reaction, or a molecular chain grown by radical species newly generated during the reaction.
Therefore, according to free radical polymerization, the composition of the copolymer becomes non-uniform compared to living radical polymerization, and a relatively low molecular weight copolymer is also included, so the above adhesive layer aggregates compared to living radical polymerization. Power tends to be low. However, if the breaking point strength can be adjusted within the above range, for example, by adjusting the composition of the acrylic copolymer, an acrylic copolymer obtained by free radical polymerization can be used as the acrylic copolymer. may

The acrylic copolymer obtained by the living radical polymerization is obtained by copolymerizing a monomer mixture containing 2-ethylhexyl acrylate from the viewpoint of increasing the wettability of the pressure-sensitive adhesive layer (adhesive strength at the interface with the adherend). The resulting acrylic copolymer is preferred.
In this case, the preferred content of 2-ethylhexyl acrylate in the total monomer mixture is 80-98% by weight. When the content of 2-ethylhexyl acrylate is 80% by weight or more, the glass transition point of the acrylic copolymer is lowered, and the wettability of the pressure-sensitive adhesive layer (adhesive strength at the interface with the adherend) is increased. When the content of 2-ethylhexyl acrylate is 98% by weight or less, the pressure-sensitive adhesive layer has appropriate hardness and sufficient cohesion. A more preferable lower limit to the content of 2-ethylhexyl acrylate is 90% by weight, and a more preferable upper limit is 97% by weight.

The acrylic copolymer obtained by the free radical polymerization is preferably an acrylic copolymer obtained by copolymerizing a monomer mixture containing butyl acrylate and 2-ethylhexyl acrylate.
In this case, the preferred content of butyl acrylate in the total monomer mixture is 40-80% by weight. When the content of butyl acrylate is 40% by weight or more, the pressure-sensitive adhesive layer has an appropriate hardness, sufficient cohesive force, and high adhesive force. When the content of butyl acrylate is 80% by weight or less, it is possible to prevent the pressure-sensitive adhesive layer from becoming too hard and lowering the wettability (adhesive strength at the interface with the adherend). The preferred content of 2-ethylhexyl acrylate in the total monomer mixture is 10-40% by weight. When the content of 2-ethylhexyl acrylate is 10% by weight or more, the pressure-sensitive adhesive layer has sufficient adhesive strength. When the content of 2-ethylhexyl acrylate is 40% by weight or less, it is possible to prevent the pressure-sensitive adhesive layer from becoming too soft and reducing the cohesion.

The above monomer mixture may contain other copolymerizable monomers other than butyl acrylate and 2-ethylhexyl acrylate, if desired.
Examples of other polymerizable monomers that can be copolymerized include (meth)acrylic acid alkyl esters in which the alkyl group has 1 to 3 carbon atoms, (meth)acrylic acid alkyl esters in which the alkyl group has 13 to 18 carbon atoms, functional monomers and the like.

Examples of (meth)acrylic acid alkyl esters having 1 to 3 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, and (meth)acrylic acid. isopropyl and the like. Examples of (meth)acrylic acid alkyl esters in which the alkyl group has 13 to 18 carbon atoms include tridecyl methacrylate and stearyl (meth)acrylate. Examples of the functional monomers include hydroxyalkyl (meth)acrylate, glycerin dimethacrylate, glycidyl (meth)acrylate, 2-methacryloyloxyethyl isocyanate, (meth)acrylic acid, itaconic acid, maleic anhydride, crotonic acid, maleic acid, fumaric acid and the like.

Various polymerization methods may be employed in the living radical polymerization. For example, the TERP method, the RAFT method, the NMP method and the like can be mentioned. An organic tellurium compound is used in the TERP method, a RAFT agent in the RAFT method, and a nitroxide compound in the NMP method, and if necessary, a radical polymerization initiator is used in combination. Among them, organic tellurium polymerization initiators are preferable as polymerization initiators for initiating living radical polymerization. By using the organotellurium polymerization initiator, it is possible to polymerize with the same initiator without protecting any functional monomer having a polar functional group such as a hydroxyl group or a carboxyl group, thereby obtaining a copolymer having a uniform molecular weight and composition. A polymer can be obtained.

The organic tellurium polymerization initiator is not particularly limited as long as it is generally used for living radical polymerization. Chloro-4-(methyltheranyl-methyl)benzene, 1-hydroxy-4-(methyltheranyl-methyl)benzene, 1-phenoxycarbonyl-4-(2-methyltheranyl-propyl)benzene and the like.
RAFT agents such as S-cyanomethyl-S-dodecyltrithiocarbonate, 2-cyano-2-propyl dithiobenzoate, S-(2-cyano-2-propyl)-S-dodecyltrithiocarbonate, 2-methyl -2-[(dodecylsulfanylthiocarbonyl)sulfanyl]propanoic acid.
Examples of nitroxide compounds include di-tert-butyl-nitroxide, 4-carboxy-2,2,6,6-tetramethylpiperidine-1-oxyl, tetramethyl-isoindoline-1-oxyl, tetraethyl-isoindoline-1- oxyl, N-tert-butyl-N-[1-diethylphosphono-(2,2-dimethylpropyl)] nitroxide, 2,2,5-trimethyl-4-phenyl-3-azahexane-3-nitroxide and the like. be done.
These compounds may be used alone or in combination of two or more.

Examples of radical polymerization initiators used according to need include organic peroxides and azo compounds. Also in the living radical polymerization, an azo compound may be used as a polymerization initiator for the purpose of accelerating the polymerization rate within a range that does not impair the effects of the present invention.

Examples of the organic peroxide include 1,1-bis(t-hexylperoxy)-3,3,5-trimethylcyclohexane, t-hexylperoxypivalate, t-butylperoxypivalate, 2,5 -dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, t-hexylperoxy-2-ethylhexanoate, t-butylperoxy-2-ethylhexanoate, t-butylperoxy isobutyrate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxylaurate and the like.
The azo compound is not particularly limited as long as it is generally used for radical polymerization. Examples of the azo compound include 2,2'-azobis(isobutyronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobis(2,4-dimethylvaleronitrile) , 2,2′-azobis(4-methoxy-2,4-dimethylvaleronitrile), 1,1-azobis(cyclohexane-1-carbonitrile), 1-[(1-cyano-1-methylethyl)azo] formamide, 4,4'-azobis(4-cyanovaleric acid), dimethyl-2,2'-azobis(2-methylpropionate), dimethyl-1,1'-azobis(1-cyclohexanecarboxylate), 2 , 2′-azobis{2-methyl-N-[1,1′-bis(hydroxymethyl)-2-hydroxyethyl]propionamide}, 2,2′-azobis[2-methyl-N-(2-hydroxy ethyl)propionamide], 2,2′-azobis[N-(2-propenyl)-2-methylpropionamide], 2,2′-azobis(N-butyl-2-methylpropionamide), 2,2′ -azobis(N-cyclohexyl-2-methylpropionamide), 2,2'-azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis{2-[1- (2-Hydroxyethyl)-2-imidazolin-2-yl]propane}dihydrochloride, 2,2′-azobis[2-(2-imidazolin-2-yl)propane], 2,2′-azobis(2 -amidinopropane) dihydrochloride, 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] tetrahydrate, 2,2'-azobis(1-imino-1-pyrrolidino- 2-methylpropane) dihydrochloride, 2,2′-azobis(2,4,4-trimethylpentane) and the like.
These polymerization initiators may be used alone or in combination of two or more.

A dispersion stabilizer may be used when radically reacting the monomer mixture. Examples of the dispersion stabilizer include polyvinylpyrrolidone, polyvinyl alcohol, methylcellulose, ethylcellulose, poly(meth)acrylic acid, poly(meth)acrylic acid ester, polyethylene glycol and the like.

When a polymerization solvent is used for the radical reaction of the monomer mixture, the polymerization solvent is not particularly limited. Nonpolar solvents such as hexane, cyclohexane, octane, toluene, and xylene can be used as the polymerization solvent. As the polymerization solvent, for example, highly polar solvents such as water, methanol, ethanol, propanol, butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, dioxane, and N,N-dimethylformamide can be used. These polymerization solvents may be used alone or in combination of two or more. The polymerization temperature is preferably 0 to 110° C. from the viewpoint of polymerization rate.

The weight average molecular weight (Mw) of the acrylic copolymer has a preferred lower limit of 400,000 and a preferred upper limit of 1,500,000. When the weight-average molecular weight is 400,000 or more, the pressure-sensitive adhesive layer has an appropriate hardness, sufficient cohesive force, and high adhesive force. When the weight-average molecular weight is 1,500,000 or less, the pressure-sensitive adhesive layer has sufficient adhesive strength. A more preferable lower limit of the weight average molecular weight is 500,000, and a more preferable upper limit thereof is 1,400,000. In order to adjust the weight average molecular weight to the above range, polymerization conditions such as polymerization initiator and polymerization temperature may be adjusted.

The preferred upper limit of the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the acrylic copolymer (molecular weight distribution, Mw/Mn) is 10. If Mw/Mn is 10 or less, the content of low-molecular-weight components and the like is low, so that the cohesive force and wettability (adhesive strength at the interface with the adherend) of the pressure-sensitive adhesive layer are increased. This makes it easier to achieve both stress relaxation and holding power of the double-sided adhesive tape. A more preferable upper limit of Mw/Mn is 8, a still more preferable upper limit is 5, and a particularly preferable upper limit is 3. In order to adjust Mw/Mn to the above range, it is sufficient to select the reaction system of the radical reaction or adjust the polymerization conditions such as the polymerization initiator and the polymerization temperature. The molecular weight distribution (Mw/Mn) of the acrylic copolymer is usually 1 or more.
The number average molecular weight (Mn) and weight average molecular weight (Mw) are weight average molecular weights in terms of standard polystyrene by GPC (Gel Permeation Chromatography). For GPC, for example, 2690 Separations Model (manufactured by Waters) can be used. Using a UV detector (detection wavelength 254 nm) as a detector and tetrahydrofuran (THF) as a mobile phase, GPC measurement is performed under the conditions of a sample flow rate of 1 mL / min and a column temperature of 40 ° C. to measure the molecular weight distribution of polystyrene equivalent molecular weight. . As a column, for example, two "GPC KF-806L" manufactured by shodex are connected in series and used.

The preferred upper limit of the ratio (molecular weight distribution, Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the sol content of the adhesive layer is 8. If Mw/Mn is 8 or less, the content of low-molecular-weight components and the like is small, so that the cohesive force and wettability (adhesive strength at the interface with the adherend) of the pressure-sensitive adhesive layer are increased. This makes it easier to achieve both stress relaxation and holding power of the double-sided adhesive tape. A more preferable upper limit of Mw/Mn is 7, a still more preferable upper limit is 5, and a particularly preferable upper limit is 3. In order to adjust Mw/Mn to the above range, it is sufficient to select the reaction system of the radical reaction or adjust the polymerization conditions such as the polymerization initiator and the polymerization temperature. The molecular weight distribution (Mw/Mn) of the gel content of the pressure-sensitive adhesive layer is usually 1 or more.
The molecular weight distribution of the sol content of the pressure-sensitive adhesive layer can be measured by the following method. First, 0.05 g of the adhesive layer is taken out from the adhesive tape, made into a solution having a concentration of 0.1% by weight or less using tetrahydrofuran (THF), and immersed with shaking at room temperature for 24 hours. Thereafter, the immersion liquid is filtered through a 200-mesh filter, and the obtained filtrate is used as a sample solution containing the sol of the pressure-sensitive adhesive layer. The resulting sample solution is supplied to a gel permeation chromatograph (GPC, e.g. Waters "e2695") equipped with a UV detector (detection wavelength 254 nm), using tetrahydrofuran (THF) as the mobile phase, GPC measurement is performed under the conditions of a sample flow rate of 1 mL/min and a column temperature of 40° C. to measure the molecular weight distribution of polystyrene equivalent molecular weight. As a column, for example, two "GPC KF-806L" manufactured by shodex are connected in series and used.

The pressure-sensitive adhesive layer may contain a tackifying resin.
Examples of the tackifying resin include rosin ester-based resins, hydrogenated rosin-based resins, terpene-based resins, terpene phenol-based resins, coumarone-indene-based resins, alicyclic saturated hydrocarbon-based resins, C5-based petroleum resins, and C9-based resins. petroleum resins, C5-C9 copolymer petroleum resins, and the like. These tackifying resins may be used alone or in combination of two or more.

The content of the tackifying resin is not particularly limited, but the preferred lower limit is 10 parts by weight and the preferred upper limit is 60 parts by weight with respect to 100 parts by weight of the acrylic copolymer. When the content of the tackifying resin is 10 parts by weight or more, the adhesive strength of the adhesive layer increases. When the content of the tackifying resin is 60 parts by weight or less, it is possible to prevent the pressure-sensitive adhesive layer from becoming too hard and the pressure-sensitive adhesive strength or wettability (adhesive strength at the interface with the adherend) from deteriorating. can.

The pressure-sensitive adhesive layer has a crosslinked structure formed between the main chains of the resin (for example, the acrylic copolymer, the tackifier resin, etc.) constituting the pressure-sensitive adhesive layer by adding a cross-linking agent. is preferred.
The cross-linking agent is not particularly limited, and examples thereof include an isocyanate-based cross-linking agent, an aziridine-based cross-linking agent, an epoxy-based cross-linking agent, and a metal chelate-type cross-linking agent. Among them, an isocyanate-based cross-linking agent is preferable. By adding an isocyanate-based cross-linking agent to the pressure-sensitive adhesive layer, the isocyanate group of the isocyanate-based cross-linking agent and the alcohol in the resin (for example, the acrylic copolymer, the tackifier resin, etc.) constituting the pressure-sensitive adhesive layer and reactive hydroxyl groups to loosen the cross-linking of the pressure-sensitive adhesive layer. Therefore, the pressure-sensitive adhesive layer can disperse intermittently applied peeling stress, thereby further improving the pressure-sensitive adhesive strength of the double-sided pressure-sensitive adhesive tape.
The amount of the cross-linking agent to be added is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 7 parts by weight, per 100 parts by weight of the acrylic copolymer.

The degree of cross-linking of the pressure-sensitive adhesive layer is preferably 5 to 60% by weight, more preferably 10 to 55% by weight, because it may become easy to peel off from the adherend when a large stress is applied, whether it is too high or too low. More preferably, 15 to 50% by weight is particularly preferred.
The degree of cross-linking of the pressure-sensitive adhesive layer was measured by collecting W ₁ (g) of the pressure-sensitive adhesive layer, immersing the pressure-sensitive adhesive layer in ethyl acetate at 23°C for 24 hours, and filtering the insoluble matter through a 200-mesh wire mesh. Then, the residue on the wire mesh is vacuum-dried, and the weight W ₂ (g) of the dried residue is measured and calculated by the following formula (1).
Degree of cross-linking (% by weight) = 100 x _W2 / _W1 (1)

The pressure-sensitive adhesive layer may contain a silane coupling agent for the purpose of improving the adhesive strength. The silane coupling agent is not particularly limited, and examples thereof include epoxysilanes, acrylsilanes, methacrylsilanes, aminosilanes, isocyanatesilanes and the like. The amount of the additive added is preferably 0.01 to 10 parts by weight, more preferably 0.02 to 5% by weight, and particularly preferably 0.05 to 3 parts by weight, relative to 100 parts by weight of the acrylic copolymer. .

The pressure-sensitive adhesive layer may contain a coloring material for the purpose of imparting light-shielding properties. The coloring material is not particularly limited, and examples thereof include carbon black, aniline black, titanium oxide, and the like. Among them, carbon black is preferable because it is relatively inexpensive and chemically stable.

The thickness of the pressure-sensitive adhesive layer is not particularly limited, but the preferred lower limit of the thickness of the pressure-sensitive adhesive layer on one side is 20 µm, and the preferred upper limit is 100 µm. When the thickness of the pressure-sensitive adhesive layer is 20 µm or more, the pressure-sensitive adhesive layer has sufficient adhesive strength. When the thickness of the pressure-sensitive adhesive layer is 100 μm or less, the stress relaxation property of the foam base material can sufficiently contribute to the stress relaxation property of the double-sided pressure-sensitive adhesive tape as a whole. A more preferable lower limit of the thickness of the pressure-sensitive adhesive layer is 30 μm, and a more preferable upper limit thereof is 80 μm.
The thickness of the pressure-sensitive adhesive layer can be measured using a dial thickness meter (eg, "ABS Digimatic Indicator" manufactured by Mitutoyo).

The 180° adhesive strength of the double-sided pressure-sensitive adhesive tape of the present invention is not particularly limited, but the preferred lower limit is 3N/25mm, and the preferred upper limit is 35N/25mm. If the 180° adhesive strength is 3 N/25 mm or more, the adhesive strength of the double-sided adhesive tape is sufficient. If the 180° adhesive strength is 35 N/25 mm or less, the reworkability of the double-sided pressure-sensitive adhesive tape is enhanced, and re-adhesion becomes possible.
The 180° adhesive strength can be obtained by measuring according to JIS Z 0237.

The double-sided pressure-sensitive adhesive tape of the present invention preferably has a peeling time of 1000 minutes or longer at 60° C. and 90% relative humidity as measured by a constant load peeling test. When the peeling time is 1000 minutes or more, the adhesive strength at the interface with the adherend can be increased, and the peeling of the double-sided pressure-sensitive adhesive tape at the interface with the adherend can be suppressed to increase the holding power. . More preferably, the peeling time is 2000 minutes or longer. The upper limit of the peeling time is not particularly limited.
The peeling time can be lengthened by increasing the adhesive strength or wettability of the pressure-sensitive adhesive layer (adhesive strength at the interface with the adherend), more specifically, for example, the composition of the acrylic copolymer can be lengthened by adjusting , adding a tackifying resin, or the like.

The above constant load peel test will be described in detail.
FIG. 2 shows a schematic diagram showing a constant load peeling test of the double-sided pressure-sensitive adhesive tape. First, one surface (surface) of a strip-shaped test piece 14 of double-sided adhesive tape having a size of 25 mm×50 mm is attached to a glass plate 15 . At this time, the contact area between the test piece 14 and the glass plate 15 is 25 mm×25 mm. Next, a polyethylene terephthalate film (not shown) having a thickness of 23 μm is adhered to the other surface (back surface) of the test piece 14 . After reciprocating a 2 kg rubber roller once on the back surface of the test piece 14 at a speed of 300 mm/min, it was left in an environment of 23° C. and a relative humidity of 50% for 24 hours to prepare a sample for constant load peeling test. do. At 60° C. and a relative humidity of 90%, this sample for constant load peeling test is placed so that the surface of the glass plate 15 to which the test piece 14 is bonded faces downward and is in a horizontal state. One end of the tape is pulled by a 500 g weight 16 in a direction perpendicular to the sticking surface. The time (peeling time) until the test piece 14 falls from the glass plate 15 is measured.

The thickness of the double-sided pressure-sensitive adhesive tape of the present invention is not particularly limited, but the preferred lower limit is 0.3 mm and the preferred upper limit is 2 mm. If the thickness is 0.3 mm or more, even when a large load is applied to the double-sided adhesive tape in a direction parallel to the adhesive interface, the peeling of the double-sided adhesive tape at the interface with the adherend is further suppressed. can do. If the thickness is 2 mm or less, sufficient adhesion and fixation can be achieved with the double-sided adhesive tape. A more preferable upper limit of the thickness is 1.5 mm.

Examples of the method for producing the double-sided pressure-sensitive adhesive tape of the present invention include the following methods.
First, a solvent is added to an acrylic copolymer, a tackifying resin, a cross-linking agent, etc. as necessary to prepare a solution of adhesive A, and this solution of adhesive A is applied to the surface of a foam base material, The solvent in the solution is completely removed by drying to form an adhesive layer A. Next, a release film is overlaid on the formed pressure-sensitive adhesive layer A so that the release-treated surface faces the pressure-sensitive adhesive layer A. As shown in FIG.
Next, prepare a release film different from the above release film, apply a solution of the adhesive B to the release treatment surface of this release film, and completely dry and remove the solvent in the solution. A laminate film is produced in which the pressure-sensitive adhesive layer B is formed on the surface of the mold film. The laminated film thus obtained is superimposed on the back surface of the foam substrate on which the adhesive layer A is formed so that the adhesive layer B faces the back surface of the foam substrate to prepare a laminate. Then, the laminate is pressed by a rubber roller or the like. As a result, it is possible to obtain a double-sided pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both sides of the foam base material and having the surface of the pressure-sensitive adhesive layer covered with the release film.

In addition, two sets of laminated films are prepared in the same manner, and these laminated films are laminated on both sides of the foam base material in such a manner that the pressure-sensitive adhesive layer of the laminated film faces the foam base material. A body may be produced and this laminate may be pressed by a rubber roller or the like. As a result, it is possible to obtain a double-sided pressure-sensitive adhesive tape having pressure-sensitive adhesive layers on both sides of the foam base material and having the surface of the pressure-sensitive adhesive layer covered with the release film.

The use of the double-sided pressure-sensitive adhesive tape of the present invention is not particularly limited, and for example, it is used for fixing parts in electronic equipment. The electronic device is not particularly limited, and examples thereof include televisions, monitors, portable electronic devices, and vehicle-mounted electronic devices.
Among others, the double-sided pressure-sensitive adhesive tape of the present invention is suitably used for bonding each panel or film constituting a display panel in relatively large display panels such as televisions and monitors. The double-sided pressure-sensitive adhesive tape of the present invention is a double-sided pressure-sensitive adhesive tape having a foam base material with high stress relaxation and excellent holding power. Even when fixing parts with an adhesive tape, it is preferably used. In particular, when the width of the frame portion of the display is narrow (for example, 1000 μm to 10000 μm, particularly 1500 μm to 5000 μm, especially 1800 μm to 4000 μm), the double-sided adhesive tape can be used advantageously. The double-sided pressure-sensitive adhesive tape of the present invention may have a narrow width, and the width is not particularly limited. 1800 μm, and a more preferable upper limit is 4000 μm. Even if the width of the double-sided pressure-sensitive adhesive tape of the present invention is within the above range, high holding power and stress relaxation properties can be exhibited. The shape of the double-sided pressure-sensitive adhesive tape of the present invention for these uses is not particularly limited, but examples thereof include rectangular, frame-shaped, parallelogram, circular, elliptical, donut-shaped and the like. When the shape of the double-sided pressure-sensitive adhesive tape of the present invention is rectangular, the length of the short side (width) is preferably 1000 μm as a lower limit, preferably 10000 μm as an upper limit, more preferably 1500 μm as a lower limit, and more preferably 5000 μm as an upper limit. A preferred lower limit is 1800 μm, and a more preferred upper limit is 4000 μm. When the double-faced pressure-sensitive adhesive tape of the present invention has a rectangular shape, high holding power and stress relaxation properties can be exhibited even when the length of the short side is within the above range.
Moreover, the double-sided pressure-sensitive adhesive tape of the present invention may be used for interiors of vehicles, interiors and exteriors of home appliances (for example, TVs, air conditioners, refrigerators, etc.).

According to the present invention, it is possible to provide a double-sided pressure-sensitive adhesive tape that has a foam base material and is highly stress-relaxing and yet has excellent holding power.

It is a schematic diagram which shows the shear tension test of a double-sided adhesive tape. It is a schematic diagram which shows the constant load peeling test of a double-sided adhesive tape. It is a schematic diagram which shows the holding power test of a double-sided adhesive tape.

EXAMPLES The present invention will be described in more detail with reference to Examples below, but the present invention is not limited to these Examples.

(Production of Polyurethane Foam 1 (PU1))
As the polyol, 90 parts by weight of polypropylene glycol (PPG) (weight average molecular weight: 1000) and 10 parts by weight of 1,5-pentanediol (molecular weight: 1000) were used.
To a total of 100 parts by weight of polyol, 0.7 parts by weight of an amine catalyst (Dabco LV33, manufactured by Sankyo Air Products) and 1 part by weight of a foam stabilizer (SZ5740M, manufactured by Dow Corning Toray) were added and stirred. A polyisocyanate (binuclear monomeric MDI, manufactured by Tosoh Corporation) was adjusted to an isocyanate index of 100 and added thereto. After that, the solution was mixed with nitrogen gas and stirred so as to have a concentration of 0.2 g/cm ³ to obtain a solution containing fine bubbles. The solution was applied to a predetermined thickness on a PET separator (manufactured by Nippa, V-2) having a thickness of 50 μm using an applicator, and the foam raw materials were reacted to obtain a polyurethane foam.
The glass transition point (Tg), density, 25% compressive strength and thickness of the resulting polyurethane foam were determined.

(Production of polyurethane foams 2 (PU2), 3 (PU3), and 5 (PU5))
A polyurethane foam was obtained in the same manner as polyurethane foam 1 (PU1) except that the type of polyol and/or the isocyanate index were changed as shown in Table 1.
In the production of polyurethane foam 3 (PU3), 90 parts by weight of polypropylene glycol (PPG) (weight average molecular weight: 1000) and 10 parts by weight of 1,6-hexamethylenediol (molecular weight: 1000) were used as polyols. For the polyurethane foam 2 (PU2), by adjusting the amount of nitrogen gas mixed therein, foamed sheets with thicknesses of 0.24 mm, 0.35 mm, 0.5 mm and 1.1 mm were also produced.

(Production of Polyurethane Foam 4 (PU4))
As polyols, polypropylene glycol (PPG) and ε-caprolactam were used (polyether component/polyester component mixing ratio (weight ratio)=8:1).
To a total of 100 parts by weight of polyol, 0.7 parts by weight of an amine catalyst (Dabco LV33, manufactured by Sankyo Air Products) and 1 part by weight of a foam stabilizer (SZ5740M, manufactured by Dow Corning Toray) were added and stirred. Polyisocyanate (Polymeric MDI, manufactured by Tosoh Corporation) was adjusted to have an isocyanate index of 100 and added thereto. After that, the solution was mixed with nitrogen gas and stirred so as to have a concentration of 0.2 g/cm ³ to obtain a solution containing fine bubbles. The solution was applied to a predetermined thickness on a PET separator (manufactured by Nippa, V-2) having a thickness of 50 μm using an applicator, and the foam raw materials were reacted to obtain a polyurethane foam.
The glass transition point (Tg), density, 25% compressive strength and thickness of the resulting polyurethane foam were determined.

(Production of polyurethane foams 6 (PU6), 7 (PU7), and 8 (PU8))
A polyurethane foam was obtained in the same manner as polyurethane foam 4 (PU4) except that the type of polyol and/or the isocyanate index were changed as shown in Table 1. For the polyurethane foam 7 (PU7), foamed sheets with thicknesses of 0.24 mm and 1.5 mm were also produced by adjusting the amount of nitrogen gas mixed therein.

(Polyethylene foam 1 (PE1), 2 (PE2))
A polyethylene foam having the density, 25% compressive strength and thickness shown in Table 2 was used.
IF08008 (manufactured by Sekisui Chemical Co., Ltd.) was used as the polyethylene foam 1 (PE1).
A foam obtained as follows was used as the polyethylene foam 2 (PE2).
First, 100 parts by weight of low-density polyethylene as a polyolefin resin, 4.5 parts by weight of azocarbonamide as a thermal decomposition foaming agent, 1 part by weight of zinc oxide as a decomposition temperature regulator, and 2 parts by weight as an antioxidant. ,6-di-t-butyl-p-cresol was supplied to an extruder and melt-kneaded at 130°C. A long sheet-like foam composition having a thickness of about 0.2 mm was extruded from the extruder. As the low-density polyethylene, "UBE polyethylene F420" manufactured by Ube Maruzen Polyethylene Co., Ltd. with a density of 0.920 g/cm ³ was used. Next, both sides of the long sheet-shaped foam composition were crosslinked by irradiating 4.5 Mrad of electron beams at an acceleration voltage of 500 kV. After that, the long sheet-shaped foam composition is continuously fed into a foaming furnace maintained at 250° C. by hot air and an infrared heater to heat and foam it, and to stretch it to a thickness of 0.8 mm. A foam sheet was obtained. At the time of stretching, the MD (Machine Direction (sheet feed direction)) draw ratio was set to 3.0 times, and the TD (Transverse Direction (sheet width direction)) draw ratio was set to 3.0 times.

(Production of adhesive A (living radical polymerization))
Tellurium (40 mesh, metallic tellurium, manufactured by Aldrich) 6.38 g (50 mmol) was suspended in 50 mL of tetrahydrofuran (THF), and a 1.6 mol/L n-butyllithium/hexane solution (manufactured by Aldrich) 34 .4 mL (55 mmol) was slowly added dropwise at room temperature. The reaction solution was stirred until metallic tellurium disappeared completely. To this reaction solution, 10.7 g (55 mmol) of ethyl-2-bromo-isobutyrate was added at room temperature and stirred for 2 hours. After completion of the reaction, the solvent was concentrated under reduced pressure and then distilled under reduced pressure to obtain ethyl 2-methyl-2-n-butylteranyl-propionate as a yellow oil.

In an argon-substituted glove box, 19 μL of the produced ethyl 2-methyl-2-n-butyltheranyl-propionate, V-60 (2,2′-azobisisobutyronitrile, Wako Pure Chemical Industries, Ltd. 1.4 mg (manufactured by Co., Ltd.) and 1 mL of ethyl acetate were added, the reaction vessel was sealed, and the reaction vessel was taken out from the glove box. Subsequently, while flowing argon gas into the reaction vessel, a total of 100 g of the monomer mixture and 66.5 g of ethyl acetate as a polymerization solvent were charged into the reaction vessel, and the polymerization reaction was performed at 60 ° C. for 20 hours to obtain an acrylic copolymer. A containing solution was obtained. As a monomer mixture, 97 parts by weight of 2-ethylhexyl acrylate (2EHA), 3 parts by weight of acrylic acid (AAc), and 0.1 part by weight of 2-hydroxyethyl acrylate (2HEA) were used.
The resulting acrylic copolymer-containing solution was diluted 50-fold with tetrahydrofuran (THF), and the diluted solution obtained was filtered through a filter (material: polytetrafluoroethylene, pore diameter: 0.2 μm). The obtained filtrate was supplied to a gel permeation chromatograph (manufactured by Waters, 2690 Separations Model), and GPC measurement was performed under the conditions of a sample flow rate of 1 ml/min and a column temperature of 40°C, and the polystyrene conversion of the acrylic copolymer was performed. The molecular weight was measured to obtain the molecular weight distribution (Mw/Mn). GPC KF-806L (manufactured by Showa Denko KK) was used as the column, and a differential refractometer was used as the detector. Table 2 shows the results.

Ethyl acetate is added to 100 parts by weight of the non-volatile content of the obtained acrylic copolymer-containing solution and stirred, and a total of 30 parts by weight of a tackifying resin is added and stirred to obtain an adhesive having a non-volatile content of 30% by weight. rice field. As the tackifying resin, 10 parts by weight of hydrogenated rosin resin, 10 parts by weight of rosin ester resin, and 10 parts by weight of terpene phenolic resin were used.

(Production of adhesive B (free radical polymerization))
A reactor equipped with a thermometer, a stirrer and a cooling tube was charged with 52 parts by weight of ethyl acetate, and after the atmosphere was replaced with nitrogen, the reactor was heated to initiate reflux. After 30 minutes from the boiling of ethyl acetate, 0.08 part by weight of azobisisobutyronitrile was added as a polymerization initiator. The monomer mixture was dropped uniformly and gradually over 1 hour and 30 minutes to react. The monomer mixture includes 60 parts by weight of butyl acrylate (BA), 36.9 parts by weight of 2-ethylhexyl acrylate (2EHA), 3 parts by weight of acrylic acid (AAc), and 2-hydroxyethyl acrylate (2HEA ) 0.1 part by weight was used. After 30 minutes from the end of dropping, 0.1 part by weight of azobisisobutyronitrile was added, and the polymerization reaction was continued for 5 hours. got
The molecular weight distribution (Mw/Mn) of the acrylic copolymer was determined in the same manner as above.

Ethyl acetate is added to 100 parts by weight of the non-volatile content of the obtained acrylic copolymer-containing solution and stirred, and a total of 30 parts by weight of a tackifying resin is added and stirred to obtain an adhesive having a non-volatile content of 30% by weight. rice field. As the tackifying resin, 10 parts by weight of hydrogenated rosin resin, 10 parts by weight of rosin ester resin, and 10 parts by weight of terpene phenolic resin were used.

(Production of adhesive C (free radical polymerization))
40 parts by weight of 2-ethylhexyl acrylate (2EHA), 25 parts by weight of butyl acrylate (BA), 30 parts by weight of methyl acrylate (MMA), and 5 parts by weight of vinyl acetate (VAc) were used as a monomer mixture. Except for this, an acrylic copolymer-containing solution was obtained in the same manner as in the production of adhesive B.
The molecular weight distribution (Mw/Mn) of the acrylic copolymer was determined in the same manner as above.

Ethyl acetate is added to 100 parts by weight of the non-volatile content of the obtained acrylic copolymer-containing solution and stirred, and a total of 30 parts by weight of a tackifying resin is added and stirred to obtain an adhesive having a non-volatile content of 30% by weight. rice field. As the tackifying resin, 10 parts by weight of hydrogenated rosin resin, 10 parts by weight of rosin ester resin, and 10 parts by weight of terpene phenolic resin were used.

(Example 1)
(1) Production of double-sided adhesive tape Prepare a release paper with a thickness of 150 μm, apply adhesive A to the release treatment surface of this release paper, and dry at 100 ° C. for 5 minutes to obtain an adhesive with a thickness of 0.05 mm. formed a layer. This adhesive layer was attached to the surface of polyurethane foam 1 (PU1). Then, in the same manner, the same pressure-sensitive adhesive layer as described above was adhered to the opposite surface of this polyurethane foam 1 (PU1) after peeling off the PET separator. After that, curing was performed by heating at 40° C. for 48 hours. As a result, a double-sided adhesive tape covered with release paper having a thickness of 150 μm was obtained.

(2) Measurement of Molecular Weight Distribution of Sol Content of Adhesive Layer Take out 0.05 g of the adhesive layer from the obtained double-sided adhesive tape, make a solution with tetrahydrofuran (THF) to a concentration of 0.1% by weight, and dissolve at room temperature for 24 hours at room temperature. A time shaking soak was performed. Thereafter, the immersion liquid was filtered through a 200-mesh filter, and the resulting filtrate was used as a sample solution containing the sol content of the pressure-sensitive adhesive layer. The resulting sample solution is supplied to a gel permeation chromatograph (GPC) equipped with a UV detector (detection wavelength 254 nm), using tetrahydrofuran (THF) as the mobile phase, sample flow rate 1 mL / min, column temperature GPC measurement was performed at 40°C. The molecular weight distribution (Mw/Mn) of the sol content of the pressure-sensitive adhesive layer was obtained from the obtained polystyrene-equivalent molecular weight. Two columns were used by connecting them in series. The following GPC and columns were used.
GPC: e2695 manufactured by Waters
Column: GPC KF-806L manufactured by shodex

(3) Shear Tensile Test FIG. 1 shows a schematic diagram showing a shear tensile test of the double-sided adhesive tape. First, a test piece 18 of double-sided adhesive tape having a size of 25 mm×4 mm and two SUS plates 19 having a size of 125 mm×50 mm and a thickness of 2 mm were laminated as shown in FIG. This laminate was crimped using a weight of 5 kg for 10 seconds and then allowed to stand still for 24 hours to prepare a sample for a shear tensile test in which two SUS plates 19 were bonded together with a test piece 18 interposed therebetween. . After fixing one of the SUS plates 19 of this shear tensile test sample, under the condition of 23° C., the upper one of the other SUS plate 19 is applied in the shear direction (the direction of the arrow in the figure) at 0.1 mm/min. The force (strength at break) applied to the test piece 18 when it was pulled and the test piece 18 broke was measured. Further, the displacement until the test piece 18 was broken was measured, and this was taken as the peeling stroke.

(4) Constant Load Peeling Test FIG. 2 shows a schematic diagram showing the constant load peeling test of the double-sided adhesive tape. First, one surface (front surface) of a strip-shaped test piece 14 of double-sided adhesive tape having a size of 25 mm×50 mm was attached to a glass plate 15 . At this time, the contact area between the test piece 14 and the glass plate 15 was 25 mm×25 mm. Next, a polyethylene terephthalate film (not shown) having a thickness of 23 μm was attached to the other surface (rear surface) of the test piece 14 . After reciprocating a 2 kg rubber roller once from the back side of the test piece 14 at a speed of 300 mm/min, it was left in an environment of 23° C. and a relative humidity of 50% for 24 hours to prepare a sample for constant load peeling test. bottom. At 60° C. and a relative humidity of 90%, this sample for constant load peeling test is placed so that the surface of the glass plate 15 to which the test piece 14 is bonded faces downward and is in a horizontal state. One end of the tape was pulled by a weight 16 of 500 g in a direction perpendicular to the sticking surface. The time (peeling time) until the test piece 14 fell from the glass plate 15 was measured.

(Examples 2 to 13, Comparative Examples 1 to 5)
A double-sided adhesive tape was obtained in the same manner as in Example 1 except that the type and thickness of the foam substrate and the type of the adhesive layer were as shown in Tables 2 and 3, and the sol content of the adhesive layer. The molecular weight distribution, the above shear tensile test and the above constant load peel test were conducted.

(Example 14)
(1) Preparation of first resin layer As the first resin layer, a polyethylene terephthalate (PET) sheet (manufactured by Toray Industries, Inc., X30) having a thickness of 50 µm was prepared. The PET sheet had a tensile modulus of 4360 MPa when measured according to JIS K 7161.

(2) Production of Double-sided Adhesive Tape The obtained first resin layer was laminated on a substrate made of polyurethane foam 2 (PU2) having a thickness of 800 μm to form a substrate laminate.
The solution of the above adhesive A is applied to the release-treated surface of a release liner made of polyethylene (PE)/free paper/polyethylene (PE) that has been subjected to release treatment to a thickness of 100 μm, and dried at 100° C. for 5 minutes. A first pressure-sensitive adhesive layer having a thickness of 50 μm was formed.
On the other hand, the solution of the adhesive A was applied to the release-treated surface of another release liner made of polyethylene (PE)/wooden paper/polyethylene (PE) that had been subjected to a release treatment to a thickness of 100 μm, and the solution was applied at 100° C. for 5 minutes at 100° C. A second pressure-sensitive adhesive layer having a thickness of 50 μm was formed by drying for minutes.
Next, the obtained first pressure-sensitive adhesive layer is superimposed on the first resin layer side surface of the substrate laminate, and the obtained second pressure-sensitive adhesive layer is superimposed on the foam substrate side. , a tape laminate consisting of the first pressure-sensitive adhesive layer/first resin layer/PU foam substrate/second pressure-sensitive adhesive layer was obtained. Then, by pressing the obtained tape laminate with a rubber roller, it has a first adhesive layer / first resin layer / PU foam substrate / second adhesive layer, and each adhesive A double-sided pressure-sensitive adhesive tape having a layer surface covered with a release film was obtained. The obtained double-sided pressure-sensitive adhesive tape was subjected to the molecular weight distribution of the sol content of the pressure-sensitive adhesive layer, the shear tensile test and the constant load peel test.

(Example 15)
(1) Preparation of first resin layer As the first resin layer, a polyethylene terephthalate (PET) sheet (manufactured by Toray Industries, Inc., X30) having a thickness of 50 µm was prepared. The PET sheet had a tensile modulus of 4360 MPa when measured by a method according to JIS K 7161.

(2) Preparation of Second Resin Layer As the second resin layer, a sheet (LA2250, manufactured by Kuraray Co., Ltd.) of acrylic triblock copolymer a (acrylic TPE-a) having a thickness of 50 μm was prepared.
The tensile modulus of the acrylic TPE-a sheet was 10.1 MPa when measured by a method according to JIS K 7161.

(3) Production of double-sided adhesive tape A first resin layer similar to that of Example 14 was formed on one side of a substrate made of polyurethane foam 2 (PU2) having a thickness of 800 µm, and a second resin layer was formed on the other side. A sheet made of the acrylic triblock copolymer a was laminated and thermally laminated at 80 ° C. to form a base laminate consisting of the first resin layer / foam base / second resin layer. .
The solution of the above adhesive A is applied to the release-treated surface of a release liner made of polyethylene (PE)/free paper/polyethylene (PE) that has been subjected to release treatment to a thickness of 100 μm, and dried at 100° C. for 5 minutes. A first pressure-sensitive adhesive layer having a thickness of 50 μm was formed.
On the other hand, the solution of the adhesive A was applied to the release-treated surface of another release liner made of polyethylene (PE)/wooden paper/polyethylene (PE) that had been subjected to a release treatment to a thickness of 100 μm, and the solution was applied at 100° C. for 5 minutes at 100° C. A second pressure-sensitive adhesive layer having a thickness of 50 μm was formed by drying for minutes.
Next, the obtained first pressure-sensitive adhesive layer is applied to the first resin layer side surface of the substrate laminate consisting of the first resin layer / foam substrate / second resin layer. The second pressure-sensitive adhesive layer is superimposed on the second resin layer side, and consists of the first pressure-sensitive adhesive layer/first resin layer/foam substrate/second resin layer/second pressure-sensitive adhesive layer A tape laminate was obtained. Then, by pressing the obtained tape laminate with a rubber roller, it has a first adhesive layer/first resin layer/foam substrate/second resin layer/second adhesive layer, In addition, a double-sided pressure-sensitive adhesive tape was obtained in which the surface of each pressure-sensitive adhesive layer was covered with a release film. The obtained double-sided pressure-sensitive adhesive tape was subjected to the molecular weight distribution of the sol content of the pressure-sensitive adhesive layer, the shear tensile test and the constant load peel test.

<Evaluation>
The double-sided pressure-sensitive adhesive tapes obtained in Examples and Comparative Examples were evaluated as follows. The results are shown in Tables 2 and 3. In addition, Examples 14 and 15 were evaluated for reworkability.

(1) Holding power test FIG. 3 shows a schematic diagram showing a holding power test of the double-sided adhesive tape. First, one side (front side) of a test piece 1 having a double-sided adhesive tape size of 25 mm × 25 mm was pasted to a glass plate 2, and a 2 kg rubber roller was applied from the other side (back side) of the test piece 1 at a speed of 300 mm/min. made one round trip with Next, the aluminum plate 3 was pasted on the back surface of the test piece 1, and after pressing for 10 seconds with a weight of 5 kg from the aluminum plate 3 side and crimping, the test piece was kept in an environment of 23°C and a relative humidity of 50% for 24 hours. It was left to stand to prepare a sample for holding power test. A weight 4 of 1.5 kg or 3 kg was attached to one end of the aluminum plate 3 so as to apply a horizontal load to the test piece 1 and the aluminum plate 3 at 60° C. and a relative humidity of 90%. , the time until the weight 4 falls (peeling time) was measured. When the peeling time was 500 hours or more, it was indicated as ◯. The peeled surface was also observed, and the case where the peeling occurred at the interface with the adherend was indicated as "interface", and the case where the interlayer failure of the foam substrate was indicated as "interlayer".

(2) Evaluation of Reworkability The double-faced adhesive tapes obtained in Examples 14 and 15 were cut into a size of 5 mm wide×100 mm long to prepare a 5 mm wide sample.
The release film on the first adhesive layer side of the obtained sample was peeled off, the first adhesive layer side was attached to a 2 mm thick glass plate (width 50 mm, length 125 mm), and 2 kg was applied onto the double-sided adhesive tape. After reciprocating once at a speed of 300 mm/min, the rubber roller was allowed to stand for 24 hours in an environment of 23° C. and a relative humidity of 50%. Next, the layers of the foam substrate are torn apart, the second adhesive layer, the second resin layer, and part of the foam substrate are removed from the double-sided adhesive tape, and then the remaining double-sided adhesive tape is placed horizontally. The double-sided adhesive tape was peeled off from the glass plate by pulling at a speed of 300 mm/min in an angle direction of 30° from the direction. The reworkability of the first pressure-sensitive adhesive layer side was evaluated according to the following criteria. The same evaluation was performed on the second pressure-sensitive adhesive layer side.
◯: The double-sided adhesive tape could be removed.
x: The double-sided adhesive tape could not be removed.

According to the present invention, it is possible to provide a double-sided pressure-sensitive adhesive tape that has a foam base material and is highly stress-relaxing and yet has excellent holding power.

1 Double-sided adhesive tape size 25 mm × 25 mm test piece 2 Glass plate 3 Aluminum plate 4 Weight (1.5 kg or 3 kg)
14 Strip-shaped test piece of size 25 mm × 50 mm of double-sided adhesive tape 15 Glass plate 16 Weight (500 g)
18 Double-sided adhesive tape size 25 mm × 4 mm test piece 19 Size 125 mm × 50 mm, thickness 2 mm SUS plate

Claims (9)

A double-sided pressure-sensitive adhesive tape having a foam substrate and adhesive layers containing an acrylic copolymer laminated on both sides of the foam substrate,
The strength at break measured by the following shear tensile test is 12 N or more,
The pressure-sensitive adhesive layer has a sol content molecular weight distribution of 8 or less,
The foam substrate is a polyurethane foam
A double-sided adhesive tape characterized by:
(Shear tensile test)
Two SUS plates each having a size of 125 mm×50 mm and a thickness of 2 mm are attached to each other using a test piece of double-sided adhesive tape having a size of 25 mm×4 mm to prepare a sample for a shear tensile test. After fixing one SUS plate of the sample for the shear tensile test, pull the upper one of the other SUS plate in the shear direction at 0.1 mm / min under the condition of 23 ° C. When the test piece breaks Measure the force (strength at break) applied to the test piece. 2. The double-sided pressure-sensitive adhesive tape according to claim 1, wherein the acrylic copolymer has a molecular weight distribution of 8 or less. 3. The double-sided pressure-sensitive adhesive tape according to claim 1 , wherein the foam substrate has a 25% compressive strength of 20 kPa or more. The double-sided pressure-sensitive adhesive tape according to claim 1, 2 or 3, wherein the polyurethane foam has a density of 170 kg/m ³ or more. The polyurethane foam is a polyurethane foam made of a urethane resin composition containing polyisocyanate and polyol, and the content of the polyisocyanate in the urethane resin composition is 15 parts by weight or less with respect to 100 parts by weight of the polyol. 5. The double-sided pressure-sensitive adhesive tape according to claim 1, 2, 3 or 4, characterized in that: 6. The double-sided pressure-sensitive adhesive tape according to claim 1 , wherein the polyurethane foam has a 25% compressive strength of 40 kPa or less. 7. The double-sided pressure-sensitive adhesive tape according to claim 1, 2, 3, 4, 5 or 6 , wherein the foam substrate has a thickness of 100 [mu]m or more and 2000 [mu]m or less. 8. The double-sided pressure-sensitive adhesive tape according to claim 1, wherein a resin sheet is laminated on one or both surfaces of the foam substrate. 9. The double-sided pressure-sensitive adhesive tape according to claim 1, 2, 3, 4, 5, 6, 7 or 8, having a width of 1000 [mu]m or more and 10000 [mu]m or less.

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