Adhesive tape

Abstract

To provide an adhesive tape which is excellent in conformity and adhesion with respect to an adherend, particularly, a hard adherend so that when the adhesive tape is peeled, it is not required to be embrittled by being heated or by using an organic solvent or the like and does not remain on the adherend, and can be peeled by being horizontally stretched.SOLUTION: The present invention relates to the adhesive tape which is an adhesive tape comprising an adhesive layer having a thickness of greater than 150 μm and less than 1,500 μm, an elongation at break point of 600-3,000%, and a stress at break point of 2.5-80.0 MPa. The adhesive tape is excellent in conformity and adhesion with respect to an adherend, particularly, a hard adherend so that when the adhesive tape is peeled, it is not required to be embrittled by being heated or by using an organic solvent or the like and does not remain on the adherend, and can be peeled by being horizontally stretched.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an adhesive tape. [Background technology]

[0002] Adhesive tapes are widely used in situations such as fixing components constituting electronic devices. Specifically, the adhesive tapes are used for fixing sheet metals constituting relatively large electronic devices such as flat-screen televisions, home appliances, and office automation equipment, fixing exterior parts to housings, and fixing rigid parts such as exterior parts and batteries to relatively small electronic devices such as mobile electronic terminals, cameras, and personal computers. These rigid parts may have uneven shapes or distortions, and adhesive tapes are required to have the ability to follow these surface shapes while exhibiting strong adhesive strength.

[0003] Furthermore, in the field of office automation equipment such as flat-screen televisions, home appliances, printers, and copiers, reusable parts used in products are increasingly being disassembled and reused after use for the purpose of saving resources from an environmental perspective. In this case, if adhesive tape is used, it is necessary to peel off the adhesive tape attached to the parts, but there are problems with this, such as the adhesive remaining on the adherend, the adhesive tape being torn, or the double-sided adhesive tape being destroyed between the nonwoven fabric layers.

[0004] In addition, when conventional adhesive tapes are used to firmly bond hard materials such as metals and plastics together, it is necessary to heat them to soften the adhesive components and peel them off, but in this case, the metal or plastic of the adherend that you want to reuse will also be affected by deterioration due to heat. Similarly, adhesive tapes can be embrittled using organic solvents and peeled off, but this causes the same problem of deterioration of the adherend as in the case of heating.

[0005] In response to the above problems, a pressure-sensitive adhesive sheet strip consisting of three layers has been proposed, each of which is made of a transparent adhesive based on a hydrogenated vinyl aromatic block copolymer and a tackifier resin (Patent Document 1). However, when three layers based on a hydrogenated vinyl aromatic block copolymer and a tackifier are laminated, sufficient initial adhesive performance may not be obtained, and there are problems such as a decrease in adhesive strength when bonding hard adherends with large distortion together.

[0006] There is also a method of utilizing commonly used adhesive tapes with strong adhesive strength, but this method does not provide sufficient removability, which is an issue. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2004-162064 A Summary of the Invention [Problem to be solved by the invention]

[0008] The problem that the present invention aims to solve is to provide an adhesive tape that has excellent conformability and adhesion to an adherend, particularly to a hard adherend, and that has excellent removability, which means that when the adhesive tape is peeled off, there is no need to embrittle the adhesive tape by heating, organic solvents, etc., and the adhesive does not remain on the adherend, and the adhesive tape can be peeled off by stretching it in the horizontal direction. [Means for solving the problem]

[0009] As a result of extensive research, the present inventors have completed the present invention to solve the above problems. The present invention provides an adhesive tape having an adhesive layer, the adhesive tape having a thickness greater than 150 μm and less than 1500 μm, an elongation at break of 600 to 3000%, and a stress at break of 2.5 to 80.0 MPa. Effect of the Invention

[0010] The adhesive tape of the present invention has excellent conformability and can firmly bond even when hard adherends such as metals and plastics are bonded together, and when peeling the two apart, there is no need to embrittle the adhesive tape by heating or organic solvents, and no adhesive residue is left on the adherends, so the tape can be peeled off cleanly by stretching it horizontally, making it possible to reuse the adherends. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The configuration of the pressure-sensitive adhesive tape of the present invention will be described in more detail below.

[0012] <Adhesive tape> The pressure-sensitive adhesive tape of the present invention has a thickness of more than 150 μm and less than 1500 μm, an elongation at break of 600 to 3000%, and a stress at break of 2.5 to 80.0 MPa.

[0013] The thickness of the adhesive tape is preferably greater than 150 μm, more preferably 170 μm or more, more preferably 200 μm or more, and particularly preferably 250 μm or more. The thickness of the adhesive tape is preferably less than 1500 μm, more preferably 1400 μm or less, more preferably 1300 μm or less, and particularly preferably 1200 μm or less. The thickness of the adhesive tape is within the above range, which makes it easy to follow the distortion of the adherend and easily obtain excellent adhesive strength, and is preferable because the stress required when stretching the adhesive tape in the horizontal direction and peeling it off again does not become too large. The adhesive tape of the present invention is also assumed to be a case where the adherend is a hard one such as metal or plastic but has a large area. In general, the larger the adherend is, the more difficult it is to suppress the distortion and mold it. By making the adhesive tape follow the distortion of such an adherend, it is possible to more accurately complete a precise mechanism such as an electronic device.

[0014] The elongation at break of the pressure-sensitive adhesive tape is preferably 600 to 3000%, more preferably 650 to 2800%, even more preferably 700 to 2700%, and even more preferably 750 to 2600%. As described above, the pressure-sensitive adhesive tape of the present invention is a relatively thick pressure-sensitive adhesive tape having a thickness of more than 150 and less than 1500 μm, and has strong adhesive strength. When the strongly bonded pressure-sensitive adhesive tape of the present invention is stretched and peeled off, the elongation at break range allows the pressure-sensitive adhesive tape to be peeled off with an appropriate tensile stress even if the pressure-sensitive adhesive tape is firmly attached to the adherend, and the pressure-sensitive adhesive tape can be easily peeled off without excessive stretching in the peeling process.

[0015] The stress at break of the adhesive tape is preferably 2.5 to 80.0 MPa, more preferably 3.0 to 60.0 MPa, even more preferably 3.5 to 30.0 MPa, and even more preferably 4.0 to 20.0 MPa. When the stress at break of the adhesive tape is within the above range, the adhesive tape does not tear even when it is stretched and peeled off, and the adhesive tape is easily stretched suitably, so that the peeling operation is easy. In addition, the force required to stretch and deform the adhesive tape also depends on the thickness of the adhesive tape. For example, when an adhesive tape with a large thickness and a high stress at break is stretched and peeled off, it cannot be stretched sufficiently and cannot be peeled off.

[0016] The stress at 25% elongation of the adhesive tape is preferably 0.05 to 10.0 MPa, more preferably 0.1 to 5.0 MPa, even more preferably 0.15 to 3.0 MPa, and even more preferably 0.2 to 2.0 MPa. When the stress at 25% elongation of the adhesive tape is within the above range, the adhesive tape can have a suitable adhesive strength, and can be peeled off relatively easily even in the re-peeling process. If the stress is below the above range, there is a concern that the adhesive tape may peel off when a load is applied in the shear direction of the adhesive tape while the hard adherends are fixed together. Also, if the stress exceeds the above range, the force required to elongate the adhesive tape in the peeling process of the adhesive tape becomes excessively large.

[0017] The stress at 50% elongation of the adhesive tape is preferably 0.05 to 10.5 MPa, more preferably 0.1 to 5.5 MPa, even more preferably 0.15 to 3.5 MPa, and even more preferably 0.2 to 2.5 MPa. When the stress at 50% elongation of the adhesive tape is within the above range, the adhesive tape can have a suitable adhesive strength, and can be peeled off relatively easily even in the peeling step. If the stress is below the above range, there is a concern that the adhesive tape may peel off when a load is applied in the shear direction of the adhesive tape while the hard adherends are fixed together. Also, if the stress exceeds the above range, the force required to elongate the adhesive tape in the peeling step of the adhesive tape becomes excessively large.

[0018] The stress of the pressure-sensitive adhesive tape at 50% elongation is preferably 100 to 160% of the stress at 25% elongation, more preferably 103 to 150%, even more preferably 105 to 140%, and even more preferably 110 to 130%. By having the stress of the adhesive tape at 50% elongation be within the above range relative to the stress of the adhesive tape at 25% elongation, it is possible to stabilize the stress required for peeling during the re-peeling process of the adhesive tape.

[0019] The storage modulus E'(23°C) of the pressure-sensitive adhesive tape at 23°C is 1.0×10 4 ~1.0×10 8 Pa, preferably 5.0×10 4 ~5.0×10 7 Pa is more preferably 1.0×10 5 ~1.0×10 7 More preferably, the temperature is 3.0×10 Pa. 5 ~8.0×10 6 It is more preferable that the stress at break of the adhesive tape is in the above range, so that the adhesive tape can easily follow the distortion of the adherend and can easily obtain excellent adhesive strength, and the dimensional stability of the adhesive tape can be ensured, so that suitable application workability can be obtained. As described above, the adhesive tape of the present invention is also assumed to be a hard adherend such as metal or plastic, but has a large area. In general, the larger the adherend, the more difficult it is to mold the tape while suppressing distortion. If the adhesive tape has the above storage modulus range, the adhesive tape can follow the distortion of the adherend as described above, and suitable adhesive strength can be obtained.

[0020] The 180° peel adhesive strength of the pressure-sensitive adhesive tape is preferably 5N / 20mm or more, more preferably 7N / 20mm or more, even more preferably 9N / 20mm or more, and even more preferably 12N / 20mm or more. When the 180° peel adhesive strength of the pressure-sensitive adhesive tape is within the above range, excellent adhesiveness is easily obtained even when the adherends are rigid bodies. In the case of a pressure-sensitive adhesive tape having elongation as in the present invention, if the 180° peel adhesive strength falls below the above range, it is suggested that the interfacial adhesive strength to the adherend is low. Therefore, when used to bond rigid bodies together, there is a concern that sufficient adhesive behavior will not be obtained.

[0021] <Adhesive layer>

[0022] The adhesive tape of the present invention includes an adhesive layer. As the adhesive layer, a conventionally known adhesive can be used.

[0023] The thickness of the adhesive layer is changed depending on the configuration of the adhesive tape of the present invention. Provided that the thickness range of the adhesive tape of the present invention is satisfied, it is preferably larger than 150 μm, more preferably 170 μm or more, more preferably 200 μm or more, and particularly preferably 250 μm or more. The thickness of the adhesive tape is preferably less than 1500 μm, preferably 1400 μm or less, more preferably 1300 μm or less, and particularly preferably 1200 μm or less. When a substrate is provided in the adhesive tape of the present invention, the thickness of the substrate layer is preferably 1 / 2 to 1 / 500, more preferably 1 / 3 to 1 / 300, even more preferably 1 / 5 to 1 / 200, and even more preferably 1 / 10 to 1 / 50. When the thickness ratio of the adhesive layer to the substrate layer of the adhesive tape is within the above range, the adhesive tape can have excellent adhesion and removability. In the pressure-sensitive adhesive tape of the present invention, the cohesive strength of the pressure-sensitive adhesive layer is lower than that of the substrate, so if the pressure-sensitive adhesive layer is thicker than the above range, there is a possibility that only the pressure-sensitive adhesive layer will remain on the adherend in the re-peeling process of the pressure-sensitive adhesive tape. Also, if the pressure-sensitive adhesive layer is thinner than the above range, there is a concern that the pressure-sensitive adhesive layer cannot follow the uneven surface of the adherend, resulting in a significant decrease in adhesive strength.

[0024] The stress at break of the adhesive layer is preferably 0.5 to 25.0 MPa, more preferably 0.8 to 20.0 MPa, even more preferably 1.0 to 17.0 MPa, and even more preferably 1.2 to 15.0 MPa. When the stress at break of the adhesive layer is within the above range, excellent adhesiveness can be exhibited, and it is preferable that the adhesive component is unlikely to remain on the adherend when the adhesive tape of the present invention is stretched in the horizontal direction and peeled off.

[0025] Examples of the adhesive used in the adhesive layer include acrylic adhesives, urethane adhesives, rubber adhesives such as synthetic rubber adhesives and natural rubber adhesives, and silicone adhesives.

[0026] (Acrylic adhesive) The acrylic adhesive may contain an acrylic polymer and, if necessary, additives such as a tackifier resin and a crosslinking agent.

[0027] The acrylic polymer can be produced, for example, by polymerizing a monomer mixture containing a (meth)acrylic monomer. As the (meth)acrylic monomer, for example, an alkyl (meth)acrylate having an alkyl group having 1 to 12 carbon atoms can be used. For example, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, n-hexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, etc. can be used alone or in combination of two or more kinds. As the alkyl(meth)acrylate having an alkyl group of 1 to 12 carbon atoms, it is preferable to use an alkyl(meth)acrylate having an alkyl group of 4 to 12 carbon atoms, it is more preferable to use an alkyl(meth)acrylate having an alkyl group of 4 to 8 carbon atoms, and it is particularly preferable to use n-butyl acrylate in order to ensure excellent adhesion to the adherend.

[0028] The alkyl (meth)acrylate having an alkyl group having 1 to 12 carbon atoms is preferably used in a range of 80% by mass to 98.5% by mass, and more preferably 90% by mass to 98.5% by mass, based on the total amount of monomers used in the production of the acrylic polymer.

[0029] As the monomers usable in the production of the acrylic polymer, in addition to the above-mentioned ones, highly polar vinyl monomers can be used as necessary. As the highly polar vinyl monomer, for example, (meth)acrylic monomers such as a (meth)acrylic monomer having a hydroxyl group, a (meth)acrylic monomer having a carboxyl group, and a (meth)acrylic monomer having an amide group can be used alone or in combination of two or more kinds.

[0030] Examples of the vinyl monomer having a hydroxyl group that can be used include (meth)acrylic monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxyhexyl (meth)acrylate.

[0031] As the vinyl monomer having a carboxyl group, (meth)acrylic monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, (meth)acrylic acid dimer, crotonic acid, and ethylene oxide modified succinic acid acrylate can be used, and among them, it is preferable to use acrylic acid.

[0032] As the vinyl having an amide group, a (meth)acrylic monomer such as N-vinylpyrrolidone, N-vinylcaprolactam, acryloylmorpholine, acrylamide, or N,N-dimethylacrylamide can be used.

[0033] As the highly polar vinyl monomer, in addition to those mentioned above, vinyl acetate, ethylene oxide modified succinic acid acrylate, 2-acrylamido-2-methylpropanesulfonic acid and other sulfonic acid group-containing monomers can be used.

[0034] The highly polar vinyl monomer is preferably used in the range of 1.5% by mass to 20% by mass, more preferably 1.5% by mass to 10% by mass, and even more preferably 2% by mass to 8% by mass, relative to the total amount of monomers used in producing the acrylic polymer, since this allows for the formation of a pressure-sensitive adhesive layer that is well balanced in terms of cohesive strength, holding power, and adhesiveness.

[0035] Among the highly polar vinyl monomers, the vinyl monomer having a hydroxyl group is preferably used when the adhesive contains an isocyanate-based crosslinking agent.Specifically, the vinyl monomer having a hydroxyl group is preferably 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, or 6-hydroxyhexyl (meth)acrylate. The vinyl monomer having a hydroxyl group is preferably used in an amount of 0.01% by mass to 1.0% by mass, and more preferably 0.03% by mass to 0.3% by mass, based on the total amount of monomers used in the production of the acrylic polymer.

[0036] The acrylic polymer can be produced by polymerizing the monomers by a known polymerization method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, or an emulsion polymerization method, and is preferably produced by a solution polymerization method or a bulk polymerization method. In the polymerization, a peroxide-based thermal polymerization initiator such as benzoyl peroxide or lauroyl peroxide, an azo thermal polymerization initiator such as azobisisobutylnitrile, an acetophenone-based photopolymerization initiator, a benzoin ether-based photopolymerization initiator, a benzyl ketal-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, a benzoin-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, or the like can be used as necessary.

[0037] The weight average molecular weight of the acrylic polymer obtained by the above method is preferably 300,000 to 3,000,000, and more preferably 500,000 to 2,500,000, as calculated in terms of standard polystyrene as measured by gel permeation chromatography (GPC).

[0038] Here, the molecular weight is measured by the GPC method using a GPC apparatus (HLC-8329GPC) manufactured by Tosoh Corporation, and is expressed as a standard polystyrene equivalent value. The measurement conditions are as follows. Sample concentration: 0.5% by mass (tetrahydrofuran solution) Sample injection volume: 100 μL Eluent:THF Flow rate: 1.0mL / min Measurement temperature: 40℃ Main column: TSKgel GMHHR-H(20) x 2 Guard column: TSKgel HXL-H Detector: Differential refractometer Standard polystyrene molecular weight: 10,000 to 20 million (Tosoh Corporation)

[0039] As the acrylic pressure-sensitive adhesive, it is preferable to use one that contains a tackifier resin in order to improve the adhesion to the adherend and the surface adhesive strength. Examples of the tackifier resin that can be used include rosin-based tackifier resins, polymerized rosin-based tackifier resins, polymerized rosin ester-based tackifier resins, rosin phenol-based tackifier resins, stabilized rosin ester-based tackifier resins, disproportionated rosin ester-based tackifier resins, hydrogenated rosin ester-based tackifier resins, terpene-based tackifier resins, terpene phenol-based tackifier resins, petroleum resin-based tackifier resins, and (meth)acrylate-based tackifier resins.

[0040] Among these, as the tackifier resin, it is preferable to use disproportionated rosin ester tackifier resins, polymerized rosin ester tackifier resins, rosin phenol tackifier resins, hydrogenated rosin ester tackifier resins, (meth)acrylate resins, and terpene phenol resins alone or in combination of two or more thereof.

[0041] The tackifier resin preferably has a softening point of 30° C. to 180° C., and more preferably has a softening point of 70° C. to 140° C., in order to form a pressure-sensitive adhesive layer with high adhesive performance. When a (meth)acrylate tackifier resin is used, it is preferable to use one having a glass transition temperature of 30° C. to 200° C., and more preferably to use one having a glass transition temperature of 50° C. to 160° C.

[0042] The tackifier resin is preferably used in the range of 5 parts by mass to 65 parts by mass per 100 parts by mass of the acrylic polymer, and more preferably in the range of 8 parts by mass to 55 parts by mass, since this makes it easier to ensure adhesion to the adherend.

[0043] The acrylic adhesive preferably contains a crosslinking agent in order to further improve the cohesive strength of the adhesive layer. The crosslinking agent may be an isocyanate crosslinking agent, an epoxy crosslinking agent, a metal chelate crosslinking agent, an aziridine crosslinking agent, etc. Among them, the crosslinking agent is preferably a type of crosslinking agent that is mixed with the acrylic polymer after production to promote a crosslinking reaction, and is preferably an isocyanate crosslinking agent or an epoxy crosslinking agent that is highly reactive with the acrylic polymer.

[0044] Examples of the isocyanate crosslinking agent include tolylene diisocyanate, naphthylene-1,5-diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, and trimethylolpropane-modified tolylene diisocyanate. Particularly preferred is a trifunctional polyisocyanate compound. Examples of the trifunctional isocyanate compound include tolylene diisocyanate and its trimethylolpropane adduct, and triphenylmethane isocyanate.

[0045] As an index of the degree of crosslinking, the gel fraction value obtained by measuring the insoluble portion after immersing the pressure-sensitive adhesive layer in toluene for 24 hours is used. The gel fraction of the pressure-sensitive adhesive layer is preferably 10% by mass to 70% by mass, more preferably 25% by mass to 65% by mass, and even more preferably 35% by mass to 60% by mass in order to obtain a pressure-sensitive adhesive layer having both good cohesiveness and adhesiveness.

[0046] The gel fraction refers to a value measured by the following method. The adhesive composition is coated on a release sheet so that the thickness after drying is 50 μm, dried at 100 ° C for 3 minutes, and aged at 40 ° C for 2 days, and cut into 50 mm squares to be used as samples. Next, the mass (G1) of the above sample before immersion in toluene is measured in advance, and the toluene-insoluble portion of the sample after immersion in a toluene solution at 23 ° C for 24 hours is separated by filtering with a 300 mesh wire net, and the mass (G2) of the residue after drying at 110 ° C for 1 hour is measured, and the gel fraction is calculated according to the following formula. The weight (G3) of the conductive fine particles in the sample is calculated from the mass (G1) of the sample and the composition of the adhesive. Gel fraction (mass%)=(G2-G3) / (G1-G3)×100

[0047] (Rubber adhesive) As the rubber-based adhesive, a rubber material that can generally be used as an adhesive can be used, but in a particularly preferred embodiment, a block copolymer of a polyaromatic vinyl compound and a conjugated diene compound can be suitably used, and in particular, a styrene-based resin such as a styrene-isoprene-styrene copolymer, a styrene-butadiene-styrene copolymer, a styrene-ethylene-butylene copolymer, or a styrene-ethylene-propylene copolymer can be used.

[0048] The styrene-based resin used in the adhesive of the adhesive tape of the present invention may be a styrene-isoprene copolymer or / and a styrene-isoprene-styrene copolymer or / and a mixture of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer. The styrene-based resin composed of these components gives the adhesive tape of the present invention excellent adhesive properties and holding power.

[0049] The styrene-based resin preferably contains 10% to 80% by mass of the structural unit represented by the following chemical formula (1) relative to the total mass of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer, more preferably 12% to 60% by mass, even more preferably 15% to 40% by mass, and even more preferably 17% to 35% by mass, thereby obtaining excellent adhesiveness and heat resistance.

[0050] [ka]

[0051] The styrene-based resin used may contain two or more copolymers having different structures, and may contain a combination of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer. The styrene-based resin preferably contains the styrene-isoprene copolymer in a range of 0% by mass to 80% by mass, more preferably 0% by mass to 77% by mass, even more preferably 0% by mass to 75% by mass, and even more preferably 0% by mass to 70% by mass, based on the total mass of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer. By using the styrene-based resin in the above range, it is possible to achieve both excellent adhesive performance and heat durability in the pressure-sensitive adhesive tape of the present invention.

[0052] The styrene-isoprene copolymer preferably has a weight average molecular weight measured in terms of standard polystyrene using gel permeation chromatography (GPC) (gel permeation chromatography, Tosoh Corporation SC-8020, high molecular weight column TSKgelGMHHR-H, solvent: tetrahydrofuran) in the range of 10,000 to 800,000, more preferably in the range of 30,000 to 500,000, and even more preferably in the range of 50,000 to 300,000. By being in the above range, it is possible to ensure heat flowability and compatibility when diluted with a solvent, and therefore it is more preferable to obtain an adhesive tape that has good workability in the manufacturing process and heat durability.

[0053] The styrene resin may have a single structure such as a linear structure, a branched structure, or a multi-branched structure, but it is also possible to use a mixture of resins with different structures. When a styrene resin rich in linear structures is used in the adhesive layer, it gives the adhesive tape of the present invention excellent adhesive performance. On the other hand, a branched or multi-branched structure in which a styrene block is arranged at the molecular end can have a pseudo-crosslinked structure and can provide excellent cohesive strength, thereby providing high holding power. It is preferable to use these resins in a mixture according to the required characteristics.

[0054] The method for producing the styrene-isoprene-styrene copolymer is not particularly limited, and any conventionally known production method can be applied, and the copolymer can be produced by the same method as described for the substrate.

[0055] In addition, a tackifier resin can be used for the rubber-based adhesive, and among them, it is preferable to use a tackifier resin with a softening point of 80°C or higher. This makes it possible to obtain an adhesive and an adhesive tape with excellent initial adhesion and heat durability. The softening point refers to a value measured by the method (dry bulb method) specified in JIS K2207.

[0056] As the tackifier resin, it is preferable to use one that is solid at room temperature (23°C), for example. 5petroleum resin, C 5 Series / C 9 Petroleum resins such as styrene-based petroleum resins and alicyclic petroleum resins can be used. The petroleum resins are easily compatible with the polyisoprene structure constituting the styrene-based resin, and as a result, the initial adhesive strength and heat durability of the pressure-sensitive adhesive and pressure-sensitive adhesive tape can be further improved. Said C 5 Examples of the petroleum resin that can be used include aliphatic petroleum resins, such as Escoretz 1202, 1304, and 1401 (manufactured by Tonen Chemical Co., Ltd.), Wingtack 95 (manufactured by The Goodyear Tire & Rubber Company), Quinton K100, R100, and F100 (manufactured by Zeon Corporation), Picotack 95, and Picopal 100 (manufactured by Rika Hercules). Said C 5 Series / C 9 As the petroleum resin, the above-mentioned C 5 Petroleum resin and C 9 Copolymers with petroleum resins such as Escoretz 2101 (Tonex), Quinton G115 (Zeon), and Hercotac 1149 (Rika Hercules) can be used. The alicyclic petroleum resin may be any of the above-mentioned C 9 These are obtained by hydrogenating petroleum resins, and examples of such resins that can be used include Escolez 5300 (manufactured by Tonex), Alcon P-100 (manufactured by Arakawa Chemical Industries), and Regalite R101 (manufactured by Rika Finetech).

[0057] The tackifier resin having a softening point of 80° C. or more is 5 petroleum resin, C 5 Series / C 9 In addition to the petroleum resins and alicyclic petroleum resins, for example, polymerized rosin resins, C 9 Examples of resins that can be used include petroleum resins, terpene resins, rosin resins, terpene-phenol resins, styrene resins, coumarone-indene resins, xylene resins, and phenol resins. Among them, the tackifier resin having a softening point of 80° C. or more is 5It is preferable to use a combination of a petroleum-based resin and a polymerized rosin-based resin in order to achieve both better initial adhesiveness and better heat durability. The tackifier resin having a softening point of 80°C or higher is preferably used in a range of 3% by mass to 100% by mass, more preferably 5% by mass to 80% by mass, relative to the total amount of the styrene-based resin, and more preferably 5% by mass to 80% by mass. Using the resin in a range of 5% by mass to 80% by mass is even more preferable in order to obtain a pressure-sensitive adhesive and pressure-sensitive adhesive tape that combine even better adhesion and better heat durability.

[0058] In addition, for the purpose of obtaining application property and initial adhesion in a constant temperature environment, a tackifier resin having a softening point of -5° C. or lower can be used in combination with the tackifier resin having a softening point of 80° C. or higher. The pour point refers to a value measured by a method in accordance with the method specified in JIS K2269. It is preferable to use a tackifier resin that is liquid at room temperature as the tackifier resin having a softening point of −5° C. or less. Such a tackifier resin that is liquid at room temperature is preferably selected from the above-mentioned known tackifier resins. Examples of the tackifier resin having a softening point of -5°C or less include process oil, polyester, and liquid rubber such as polybutene. Of these, the use of polybutene is preferred in order to achieve even better initial adhesion. The tackifier resin having a softening point of -5°C or less is preferably used in the range of 0% by mass to 40% by mass, and more preferably 0% by mass to 30% by mass, based on the total amount of the tackifier resin. The tackifier resin having a softening point of -5°C or less is preferably used in a range of 0% by mass to 40% by mass relative to the total amount of the styrene-based resin, and using it in a range of 0% by mass to 30% by mass can improve the initial adhesive strength, provide good adhesion, and obtain sufficient heat durability.

[0059] The mass ratio of the tackifier resin having a softening point of 80°C or higher and the tackifier resin having a softening point of -5°C or lower is preferably in the range of 5 to 50, and more preferably in the range of 10 to 30, in order to obtain a pressure-sensitive adhesive and pressure-sensitive adhesive tape that combines excellent initial adhesion and excellent holding power.

[0060] The styrene resin and the tackifier resin are preferably used in combination in a range of 0.5 to 10.0 in a mass ratio represented by [styrene resin / tackifier resin], and using in a range of 0.6 to 9.0 can improve the initial adhesive strength and obtain excellent heat durability. In addition, the mass ratio [styrene resin / tackifier resin] is preferably greater than 1 in order to prevent peeling caused by the repulsive force of the adhesive tape when it is applied to, for example, a curved surface of an adherend (repulsion resistance).

[0061] As the antiaging agent, those that can be generally used for pressure sensitive adhesives can be used, and examples thereof include those described in the section on the base material.

[0062] The pressure-sensitive adhesive layer can be produced by a casting method using extrusion molding, a uniaxial stretching method, a sequential secondary stretching method, a simultaneous biaxial stretching method, an inflation method, a tube method, a calendar method, a solution method, etc. Among these, a casting method using extrusion molding or a solvent method can be preferably used, and the method may be selected according to the compatibility of the thickness control of the pressure-sensitive adhesive layer and the lamination method with the substrate. In the case of the solvent method, a method of directly applying the adhesive to a substrate with a roll coater or the like, or a method of forming an adhesive layer on a release liner and then peeling it off before use is used.

[0063] Examples of the release liner that can be used include paper such as kraft paper, glassine paper, and wood-free paper; resin films such as polyethylene, polypropylene (OPP, CPP), and polyethylene terephthalate; laminated paper in which the above-mentioned paper and a resin film are laminated together; and paper that has been sealed with clay, polyvinyl alcohol, or the like and then treated with a release agent such as a silicone-based resin on one or both sides.

[0064] (Filler) The adhesive layer of the adhesive tape of the present invention may contain a filler.

[0065] The filler constituting the adhesive tape of the present invention can be one or more fillers selected from the group consisting of various inorganic fillers such as metals, metal hydroxides, metal oxides, silicates, carbon, and silica, and organic beads. Examples of the metal that can be used include aluminum, magnesium, zirconium, calcium, barium, tin, nickel, titanium, copper, silver, and gold. As the metal hydroxide, for example, aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, calcium hydroxide, barium hydroxide, etc. can be used. As the metal oxide, for example, silicon oxide, magnesium oxide, zinc oxide, titanium oxide, zirconium oxide, iron oxide, aluminum oxide, calcium oxide, etc. can be used. As the silicate, for example, talc and mica can be used.

[0066] The type of the filler can be selected based on the performance required for the adhesive tape. For example, when coloring, hiding property, and weather resistance are to be imparted, it is preferable to use carbon.

[0067] The shape of the filler may be either regular or irregular, but it is preferable to use one having a non-plate-like or non-scale-like shape. The non-plate-like or non-scale-like shape refers to one having an aspect ratio of about 1 to 10. Among them, one having an aspect ratio of 1 to 10 is preferable, one having an aspect ratio of 1 to 9 is more preferable, and one having an aspect ratio of 1 to 8 is even more preferable.

[0068] The filler preferably has an average particle diameter of 0.01 μm to 70 μm, and more preferably has an average particle diameter of 0.02 μm to 50 μm. In particular, when carbon is used, the average particle diameter is preferably 0.02 μm to 2 μm, more preferably 0.03 μm to 1 μm, even more preferably 0.03 μm to 0.5 μm, and even more preferably 0.05 μm to 0.1 μm. The carbon used forms aggregates in which a large number of primary particles are gathered, and the degree of development of the aggregates (structure) is indicated by the oil absorption. The oil absorption of the carbon as the filler is preferably 50 to 200 cc / 100 g, more preferably 55 to 150 cc / 100 g, even more preferably 60 to 120 cc / 100 g, and even more preferably 65 to 100 cc / 100 g.

[0069] In order to obtain excellent removability and adhesiveness, the filler is preferably used in the range of 1% by mass to 50% by volume, more preferably 2% by volume to 40% by volume, even more preferably 3% by volume to 30% by volume, and even more preferably 5% by volume to 25% by volume, based on the total mass of the components constituting the adhesive layer of the adhesive tape. By using the filler in the above range, both excellent adhesive performance and excellent removability can be achieved. (Other additives) As additives for the adhesive layer, as necessary, within the scope that does not impair the properties, additives such as other polymer components, crosslinking agents, antioxidants, ultraviolet absorbers, fillers, polymerization inhibitors, surface conditioners, antistatic agents, defoamers, viscosity modifiers, light stabilizers, weather stabilizers, heat stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, plasticizers, softeners, flame retardants, metal deactivators, silica beads, organic beads, etc.; and inorganic fillers such as silicon oxide, aluminum oxide, titanium oxide, zirconia, and antimony pentoxide can be used. <Base material> In a preferred embodiment of the pressure-sensitive adhesive tape of the present invention, a substrate is provided in addition to the pressure-sensitive adhesive layer for adhering the pressure-sensitive adhesive tape to the adherend. The pressure-sensitive adhesive layer may be provided on one side or both sides of the substrate, but is preferably provided on both sides. When the substrate is provided, the thickness is preferably 100 to 1490 μm, more preferably 120 to 1390 μm, even more preferably 150 to 1290 μm, and even more preferably 200 μm to 1190 μm. When the thickness of the substrate is within the above range, the pressure-sensitive adhesive tape can easily follow the distortion of the adherend and can easily obtain high adhesive strength, and the stress required for re-peeling the pressure-sensitive adhesive tape while stretching it in the horizontal direction is not too large, which is preferable.

[0070] The elongation at break of the substrate of the pressure-sensitive adhesive tape is preferably 600 to 3000%, more preferably 650 to 2800%, even more preferably 700 to 2700%, and even more preferably 750 to 2600%. By having the elongation at break of the substrate be equal to or greater than the lower limit of the range, even if the pressure-sensitive adhesive tape is firmly attached to the adherend, the stress for stretching the tape in the horizontal direction when the pressure-sensitive adhesive tape is peeled off is not too large, and the pressure-sensitive adhesive tape can be easily peeled off without excessive stretching in the peeling process. In addition, by having the elongation at break of the substrate be equal to or less than the upper limit of the range, the stretching distance in the horizontal direction of the tape when the pressure-sensitive adhesive tape is peeled off is not too long, which is preferable since it allows work in a small space.

[0071] The breaking stress of the substrate is preferably 2.5 to 80.0 MPa, more preferably 3.0 to 60.0 MPa, even more preferably 3.5 to 30.0 MPa, and even more preferably 4.0 to 20.0 MPa. When the breaking stress of the substrate is within the above range, the adhesive tape can be prevented from tearing even when the adhesive tape is stretched and peeled off, and the load for stretching the adhesive tape is not excessive, so that the peeling operation is easy. In addition, the force required for stretching and deforming the adhesive tape also depends on the thickness of the adhesive tape. For example, when an adhesive tape with a large thickness and a high breaking stress is stretched and peeled off, it cannot be stretched sufficiently and cannot be peeled off.

[0072] The stress at 25% elongation of the substrate is preferably 0.15 to 10.0 MPa, more preferably 0.25 to 7.0 MPa, even more preferably 0.35 to 5.0 MPa, and even more preferably 0.45 to 2.0 MPa. When the stress at 25% elongation of the adhesive tape is within the above range, the adhesive tape can have a suitable adhesive strength, and can be peeled off relatively easily even in the peeling step. If the stress is below the above range, there is a concern that the adhesive tape may peel off when a load is applied in the shear direction of the adhesive tape while the hard adherends are fixed together. Also, if the stress exceeds the above range, the force required to elongate the adhesive tape becomes excessive in the peeling step of the adhesive tape.

[0073] The stress at 50% elongation of the substrate is preferably 0.15 to 10.0 MPa, more preferably 0.25 to 7.0 MPa, even more preferably 0.35 to 5.0 MPa, and even more preferably 0.50 to 2.0 MPa. When the stress at 50% elongation of the adhesive tape is within the above range, the adhesive tape can have a suitable adhesive strength, and can be relatively easily peeled off even in the peeling step. If the stress is below the above range, there is a concern that the adhesive tape may peel off when a load is applied in the shear direction of the adhesive tape while the hard adherends are fixed together. Also, if the stress exceeds the above range, the force required to elongate the adhesive tape becomes excessive in the peeling step of the adhesive tape.

[0074] The stress of the base material of the pressure-sensitive adhesive tape at 50% elongation is preferably 100 to 160% of the stress at 25% elongation, more preferably 103 to 150%, even more preferably 105 to 140%, and even more preferably 110 to 130%. By having the stress of the adhesive tape at 50% elongation be within the above range relative to the stress of the adhesive tape at 25% elongation, it is possible to stabilize the stress required for peeling during the re-peeling process of the adhesive tape.

[0075] The storage modulus E'(23°C) of the substrate at 23°C is 1.0×10 4 ~1.0×10 8 Pa, preferably 5.0×10 4 ~5.0×10 7 Pa is more preferably 1.0×10 5 ~1.0×10 7 More preferably, the temperature is 3.0×10 Pa. 5 ~8.0×10 6It is more preferable that the stress at break of the substrate is in the above range, and therefore the adhesive tape can easily follow the distortion of the adherend and obtain excellent adhesive strength, and the dimensional stability of the adhesive tape can be ensured, so that suitable application workability can be obtained. As described above, the adhesive tape of the present invention is assumed to be a large-area adherend, even though it is a hard one such as metal or plastic. Generally, the larger the adherend, the more difficult it is to suppress distortion and mold it, but if the adhesive tape has the above storage modulus range, the adhesive tape can follow the distortion of the adherend as described above, and suitable adhesive strength can be obtained.

[0076] The material constituting the substrate of the pressure-sensitive adhesive tape of the present invention may be any material that can exhibit the above-mentioned characteristics, and for example, a block copolymer of a polyaromatic vinyl compound and a conjugated diene compound can be used, and in particular, styrene-based resins such as styrene-isoprene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-ethylenebutylene copolymer, and styrene-ethylenepropylene copolymer can be used. In addition, polyurethane resins such as ester-based polyurethane and ether-based polyurethane; polyolefin resins such as polyethylene and polypropylene; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polystyrene, polycarbonate, polymethylpentene, polysulfone, polyether ether ketone, polyether sulfone, polyether imide, polyimide film, fluorine resin, nylon, acrylic resin, etc. can also be used. Among these, styrene-based resins such as styrene-isoprene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-ethylene-butylene copolymer, and styrene-ethylene-propylene copolymer; and polyurethane resins such as ester-based polyurethane and ether-based polyurethane are preferably used because suitable elongation at break and stress at break can be easily obtained. In particular, styrene-based resins such as styrene-isoprene-styrene copolymer, styrene-butadiene-styrene copolymer, styrene-ethylene-butylene copolymer, and styrene-ethylene-propylene copolymer are preferably used.

[0077] As described above, as the base material of the pressure-sensitive adhesive tape of the present invention, a styrene-based resin film in which the main component of the resin component is a styrene-based resin is preferable. However, as the styrene-based resin film, those in which the styrene-based resin occupies more than 50% of the resin component ratio can be comprehensively used. Since the styrene-based resin is a resin exhibiting thermoplasticity, it has excellent moldability such as extrusion molding and injection molding, and thus it is easy to mold the base material for constituting the pressure-sensitive adhesive tape of the present invention. Further, the styrene-based resin is particularly likely to obtain an excellent elongation at break among resin groups generally called thermoplastic resins, and can be suitably used as the base material of the pressure-sensitive adhesive tape of the present invention.

[0078] The ratio of the styrene-based resin in the resin component contained in the styrene-based resin film is preferably 50 to 100%, more preferably 60 to 100%, still more preferably 65 to 100%, and even more preferably 70 to 100%. By being within this range, it is possible to obtain excellent elongation at break and breaking point stress of the styrene-based resin film. Further, as the materials other than the styrene-based resin contained in the styrene-based resin film, various thermoplastic resins such as polyolefin and polycarbonate can be used, and one kind or a plurality of kinds can be used simultaneously.

[0079] As one aspect for producing the pressure-sensitive adhesive tape of the present invention, the styrene-based resin used for the base material of the pressure-sensitive adhesive tape is a styrene-isoprene copolymer and / or a styrene-isoprene-styrene copolymer and / or a mixture of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer. The pressure-sensitive adhesive tape having particularly preferable elongation at break and breaking point stress can be produced from the styrene-based resin composed of the said components.

[0080] As the styrene resin, it is preferable to use one having a structural unit represented by the following chemical formula (2) in the range of 13% by mass to 60% by mass, more preferably in the range of 15% to 50% by mass, still more preferably in the range of 16% to 45% by mass, and even more preferably in the range of 17% to 35% by mass, based on the total mass of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer. Thereby, it becomes easier to obtain the elongation at break and the stress at break in a suitable range.

[0081]

Chemical formula

[0082] As the styrene resin, one containing two or more copolymers having different structures can be used, and one containing a combination of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer can be used. As the styrene resin, it is preferable to use one containing the styrene-isoprene copolymer in the range of 0% by mass to 80% by mass, more preferably in the range of 0% by mass to 70% by mass, still more preferably in the range of 0% by mass to 50% by mass, and even more preferably in the range of 0% by mass to 30% by mass, based on the total mass of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer. By setting it within the above range, it is possible to achieve both heat durability while maintaining excellent elongation at break and stress at break.

[0083] The styrene-isoprene copolymer preferably has a weight average molecular weight measured in terms of standard polystyrene using gel permeation chromatography (GPC) (gel permeation chromatography, Tosoh Corporation SC-8020, high molecular weight column TSKgelGMHHR-H, solvent: tetrahydrofuran) in the range of 10,000 to 800,000, more preferably in the range of 30,000 to 500,000, and even more preferably in the range of 50,000 to 300,000. By being in the above range, it is possible to ensure heat flowability and compatibility when diluted with a solvent, and therefore it is more preferable to obtain an adhesive tape that has good workability in the manufacturing process and heat durability.

[0084] The styrene resin may have a single structure such as a linear structure, a branched structure, or a multi-branched structure, but it is also possible to use a mixture of resins with different structures. Styrene resins rich in linear structures provide the adhesive tape of the present invention with excellent elongation at break. On the other hand, those having a branched or multi-branched structure but with styrene blocks at the molecular end can form a pseudo-crosslinked structure and provide excellent cohesive strength. For this reason, it is preferable to use a mixture according to the required mechanical properties.

[0085] The method for producing the styrene-isoprene-styrene copolymer is not particularly limited, and a conventionally known production method can be applied. For example, there is a method for sequentially polymerizing a styrene block and an isoprene block by an anionic living polymerization method, or a method for producing a block copolymer having a living active end, and then reacting it with a coupling agent to produce a coupled block copolymer.

[0086] The method for producing the styrene-isoprene copolymer is not particularly limited, and any conventionally known production method can be used, for example, a method in which a styrene block and an isoprene block are sequentially polymerized by an anionic living polymerization method.

[0087] The method for producing the mixture of the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer is not particularly limited, and a conventionally known production method can be applied. For example, there is a method in which the styrene-isoprene copolymer and the styrene-isoprene-styrene copolymer produced above are mixed and used. It is also possible to produce them as a mixture simultaneously in one polymerization step. In a more specific embodiment, the anionic living polymerization method is carried out by first polymerizing a styrene monomer using an anionic polymerization initiator in a polymerization solvent to form a polystyrene block having a living active end. Then, secondly, isoprene is polymerized from the living active end of the polystyrene block to obtain a styrene-isoprene diblock copolymer having a living active end. Subsequently, thirdly, a part of the styrene-isoprene diblock copolymer having the living active end is reacted with a coupling agent to form a coupled styrene-isoprene-styrene block copolymer. Then, fourthly, the remaining part of the styrene-isoprene diblock copolymer having the living active end is deactivated with a polymerization terminator to form a styrene-isoprene diblock copolymer.

[0088] In addition, a tackifier resin can be used in the substrate for the purpose of increasing adhesion to the adhesive layer and increasing heat resistance. Among them, a tackifier resin having a softening point of 80° C. or more can be preferably used, more preferably a softening point of 90° C. or more, even more preferably a softening point of 100° C. or more, and even more preferably a softening point of 110° C. or more. The softening point refers to a value measured by the method (dry bulb method) specified in JIS K2207.

[0089] As the tackifier resin, it is preferable to use, for example, one that is solid at room temperature (23° C.). 5 petroleum resin, C 5 Series / C 9 Petroleum resins such as cyclic petroleum resins and alicyclic petroleum resins can be used. The petroleum resin is highly compatible with the polyisoprene structure constituting a styrene-isoprene copolymer or a styrene-isoprene-styrene copolymer, and as a result, the initial adhesive strength and heat durability of the pressure-sensitive adhesive tape can be further improved. Said C 5 Examples of the petroleum resin that can be used include aliphatic petroleum resins, such as Escoretz 1202, 1304, and 1401 (manufactured by Tonen Chemical Co., Ltd.), Wingtack 95 (manufactured by The Goodyear Tire & Rubber Company), Quinton K100, R100, and F100 (manufactured by Zeon Corporation), Picotack 95, and Picopal 100 (manufactured by Rika Hercules). Said C 5 Series / C 9 As the petroleum resin, the above-mentioned C 5 Petroleum resin and C 9 Copolymers with petroleum resins such as Escoretz 2101 (Tonex), Quinton G115 (Zeon), and Hercotac 1149 (Rika Hercules) can be used. The alicyclic petroleum resin may be any of the above-mentioned C 9 These are obtained by hydrogenating petroleum resins, and examples of such resins that can be used include Escolez 5300 (manufactured by Tonex), Alcon P-100 (manufactured by Arakawa Chemical Industries), and Regalite R101 (manufactured by Rika Finetech).

[0090] The tackifier resin may be any of the above-mentioned C 5 petroleum resin, C 5 Series / C 9 In addition to the petroleum resins and alicyclic petroleum resins, for example, polymerized rosin resins, C 9 Examples of resins that can be used include petroleum resins, terpene resins, rosin resins, terpene-phenol resins, styrene resins, coumarone-indene resins, xylene resins, and phenol resins. Among them, the tackifier resin is preferably the above-mentioned C 5 It is preferable to use a combination of a petroleum-based resin and a polymerized rosin-based resin in order to achieve both better initial adhesiveness and better heat durability.

[0091] The tackifier resin is preferably used in the range of 0% to 100% by mass, more preferably 0% to 70% by mass, even more preferably 0% to 50% by mass, and even more preferably 0% to 30% by mass, based on the total amount of the styrene-isoprene copolymer or styrene-isoprene-styrene copolymer. By using the tackifier resin in the above range, it becomes easier to achieve both excellent elongation at break and heat durability of the adhesive tape while increasing the interfacial adhesion between the adhesive layer and the base layer.

[0092] In addition, the base material may contain additives such as other polymer components, crosslinking agents, antioxidants, ultraviolet absorbers, fillers, polymerization inhibitors, surface conditioners, antistatic agents, defoamers, viscosity modifiers, light resistance stabilizers, weather resistance stabilizers, heat resistance stabilizers, antioxidants, leveling agents, organic pigments, inorganic pigments, pigment dispersants, silica beads, and organic beads; and inorganic fillers such as silicon oxide, aluminum oxide, titanium oxide, zirconia, and antimony pentoxide, as necessary, within the scope of not impairing the properties.

[0093] As the antiaging agent, for example, it is preferable to use a phenol-based antiaging agent, since it can effectively improve the heat resistance stability of a styrene-isoprene copolymer or the like, and as a result, it is possible to obtain a pressure-sensitive adhesive and pressure-sensitive adhesive tape that maintain good initial adhesion and have even better heat durability. The phenolic antioxidant is generally a phenolic compound having a steric hindrance group, and is typically a monophenolic type, a bisphenolic type, or a polyphenolic type.Specific examples include 2,6-di-t-butyl-4-methylphenol, 2,2'-methylenebis(4-methyl-6-t-butylphenol), 2,2'-methylenebis(4-ethyl-6-t-butylphenol), 4,4'-thiobis(6-t-butyl-3-methylphenol), 4,4'-butylidenebis(3-methyl-6-t-butylphenol), tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane, and n-octadecyl-3-(4'-hydroxy-3'5'-di-t-butylphenyl)propionate, which can be used alone or in combination of two or more. The phenol-based anti-aging agent is preferably used in a range of 0.1 parts by mass to 5 parts by mass relative to 100 parts by mass of the styrene-isoprene block copolymer. Using the phenol-based anti-aging agent in a range of 0.5 parts by mass to 3 parts by mass can effectively improve the heat resistance stability of the styrene-isoprene copolymer, and as a result, a pressure-sensitive adhesive can be obtained that maintains good initial adhesion and has even better heat durability. The antiaging agent may be a combination of the phenolic antiaging agent and other antiaging agents such as phosphorus-based antiaging agents (also called processing stabilizers), amine-based antiaging agents, imidazole-based antiaging agents, etc., and in particular, the combination of the phenolic antiaging agent and the phosphorus-based antiaging agent can maintain good initial adhesion and obtain an adhesive with even better heat durability. Note that the phosphorus-based antiaging agent may slightly discolor (yellowing) over time in a high-temperature environment, so the amount of the antiaging agent used is preferably set appropriately in consideration of the balance between the initial adhesion, heat durability, and discoloration prevention.

[0094] Polyurethane can also be suitably used as a material for the substrate of the pressure-sensitive adhesive tape of the present invention. As the polyurethane, a reaction product of polyol (b1-1) and polyisocyanate (b1-2) can be suitably used. As the polyol (b1-1), for example, polyether polyol, polyester polyol, polycarbonate polyol, etc. can be used. Among them, as the polyol (b1-1), polyester polyol and polyether polyol can be used alone or in combination of two or more kinds in order to obtain the mechanical properties of the substrate. When the adhesive tape requires heat resistance, it is preferable to use polyester polyol, and when the adhesive tape requires water resistance and biodegradability, it is preferable to use polyether polyol.

[0095] Examples of the polyester polyol that can be used for the polyol (b1-1) include those obtained by an esterification reaction between a low molecular weight polyol and a polycarboxylic acid, polyesters obtained by a ring-opening polymerization reaction of a cyclic ester compound such as ε-caprolactone, and copolymer polyesters thereof. Examples of the low molecular weight polyol that can be used include aliphatic alkylene glycols having a molecular weight of about 50 to 300, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, neopentyl glycol, and 1,3-butanediol, and cyclohexanedimethanol.

[0096] Examples of the polycarboxylic acid that can be used in the production of the polyester polyol include aliphatic dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid; and anhydrides or esters thereof.

[0097] The polyol (b1-1) may be a polyether polyol. For example, the polyether polyol may be one obtained by addition polymerization of an alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator.

[0098] As the polyol (b1-1), a polycarbonate polyol can be used, for example, a polycarbonate polyol obtained by reacting a carbonate ester and / or phosgene with a low molecular weight polyol described later can be used. As the carbonate ester, for example, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclocarbonate, diphenyl carbonate, etc. can be used.

[0099] Examples of low molecular weight polyols that can react with the carbonate ester or phosgene include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 2,5-hexanediol, 1,7-heptanediol, 1,8 octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,4-cyclohexanedimethanol, hydroquinone, resorcinol, bisphenol A, bisphenol F, 4,4'-biphenol, and the like can be used.

[0100] In addition to the above-mentioned polyols, other polyols may be used as the polyol (b1-1). Examples of the other polyols include acrylic polyols.

[0101] As the polyisocyanate (b1-2), alicyclic polyisocyanates, aliphatic polyisocyanates, aromatic polyisocyanates, etc. can be used, and it is preferable to use alicyclic polyisocyanates.

[0102] Examples of the alicyclic polyisocyanate include isophorone diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, 4,4'-dicyclohexylmethane diisocyanate, 2,4- and / or 2,6-methylcyclohexane diisocyanate, cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, bis(2-isocyanatoethyl)-4-cyclohexylene-1,2-dicarboxylate, and 2,5- and / or 2,6-norbornane diisocyanate, dimer acid diisocyanate, and bicycloheptane triisocyanate, which may be used alone or in combination of two or more.

[0103] Examples of the method for producing polyurethane (b1) by reacting the polyol (b1-1) with the polyisocyanate (b1-2) include a method in which the polyol (b1-1) charged in a reaction vessel is heated under normal pressure or reduced pressure conditions to remove moisture, and then the polyisocyanate (b1-2) is supplied all at once or in portions and reacted.

[0104] The reaction of the polyol (b1-1) with the polyisocyanate (b1-2) is preferably carried out in such a manner that the equivalent ratio of the isocyanate groups in the polyisocyanate (b1-2) to the hydroxyl groups in the polyol (b1-1) (hereinafter referred to as the [NCO / OH equivalent ratio]) is in the range of preferably 1.0 to 20.0, more preferably 1.1 to 13.0, even more preferably 1.2 to 5.0, and particularly preferably 1.5 to 3.0.

[0105] The reaction conditions (temperature, time, etc.) of the polyol (b1-1) and the polyisocyanate (b1-2) may be appropriately set in consideration of various conditions such as safety, quality, and cost, and are not particularly limited. For example, the reaction temperature is preferably in the range of 70 to 120°C, and the reaction time is preferably in the range of 30 minutes to 5 hours. When reacting the polyol (b1-1) with the polyisocyanate (b1-2), a catalyst such as a tertiary amine catalyst or an organometallic catalyst may be used as necessary.

[0106] The reaction may be carried out in a solvent-free environment or in the presence of an organic solvent. Examples of the organic solvent include ester solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate, ketone solvents such as acetone, methyl ethyl ketone, methyl butyl ketone, and cyclohexanone, ether ester solvents such as methyl cellosolve acetate and butyl cellosolve acetate, aromatic hydrocarbon solvents such as toluene and xylene, and amide solvents such as dimethylformamide and dimethylacetamide, which can be used alone or in combination. The organic solvent may be removed during or after the production of the polyurethane (b1) by an appropriate method such as heating under reduced pressure or drying at normal pressure.

[0107] The polyurethane (b1) obtained by the above method preferably has a softening temperature of 40° C. or higher, and more preferably has a softening temperature of 50° C. or higher. The softening temperature refers to a value measured in accordance with JIS K 2207. The upper limit of the softening temperature is preferably 100° C. or lower.

[0108] The substrate may be provided with a primer layer for the purpose of further improving adhesion to the pressure-sensitive adhesive layer, or may be subjected to a surface treatment such as a sandblasting method, a solvent treatment method, or a corona discharge treatment, a chromic acid treatment, a flame treatment, a hot air treatment, an ozone treatment, an ultraviolet irradiation treatment, or an oxidation treatment.

[0109] The method for producing the substrate includes a casting method by extrusion molding, a uniaxial stretching method, a successive secondary stretching method, a simultaneous biaxial stretching method, an inflation method, a tube method, a calendar method, a solution method, etc. Among them, the casting method by extrusion molding, the uniaxial stretching method, the successive secondary stretching method, the simultaneous biaxial stretching method, the inflation method, and the tube method can be suitably used, and may be selected according to the mechanical strength required for the pressure-sensitive adhesive tape of the present invention.

[0110] The substrate may be a single layer structure, or a multi-layer structure having two or three layers or more. In the case of a multi-layer structure, it is preferable that at least one layer has the resin composition described above, since it is easy to exhibit the required mechanical properties. In addition, a substrate having a three-layer structure can be obtained by, for example, co-extruding a thermoplastic resin such as polypropylene and the styrene-isoprene-styrene copolymer. This may be used as a suitable configuration for the adhesive tape of the present invention, for example, when it is desired to provide the tape with appropriate dimensional stability and stiffness. EXAMPLES

[0111] The present invention will be explained in more detail below with reference to examples, but is not limited thereto.

[0112] [Preparation of Adhesive (1)] In a reaction vessel equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel, and a nitrogen gas inlet, 60 parts by mass of n-butyl acrylate, 35.95 parts by mass of 2-ethylhexyl acrylate, 4.0 parts by mass of acrylic acid, 0.05 parts by mass of 4-hydroxybutyl acrylate, and 0.2 parts by mass of 2,2'-azobisisobutylnitrile as a polymerization initiator were dissolved in a mixed solvent of 50 parts by mass of ethyl acetate and 20 parts by mass of n-hexane, and the mixture was polymerized at 70°C for 8 hours to obtain an acrylic copolymer solution (1) having a weight average molecular weight of 700,000. Next, 20 parts by mass of polymerized rosin ester resin (D-125, manufactured by Arakawa Chemical Industries, Ltd.) and 10 parts by mass of disproportionated rosin ester (A100, manufactured by Arakawa Chemical Industries, Ltd.) were added to 100 parts by mass of the solid content of the acrylic copolymer solution (1) having a weight average molecular weight of 700,000, and the solid content concentration was adjusted to 45% by mass using ethyl acetate to obtain an acrylic pressure-sensitive adhesive composition (1). Next, 100 parts by mass (solid content 45 parts by mass) of the acrylic adhesive composition (1) and 2.0 parts by mass of a crosslinking agent (BURNOC NC-40, isocyanate-based crosslinking agent, solid content 40% by mass, ethyl acetate solution, manufactured by DIC Corporation) were mixed, and the mixture was mixed for 10 minutes using a dispersion stirrer to obtain an adhesive (1).

[0113] [Preparation of Adhesive (2)] A reaction vessel equipped with a stirrer, reflux condenser, nitrogen inlet tube, and thermometer was charged with 75.94 parts by mass of n-butyl acrylate, 5 parts by mass of 2-ethylhexyl acrylate, 15 parts by mass of cyclohexyl acrylate, 4 parts by mass of acrylic acid, 0.06 parts by mass of 4-hydroxybutyl acrylate, and 200 parts by mass of ethyl acetate, and the mixture was heated to 65°C while stirring and blowing in nitrogen. Next, 4 parts by mass of 2,2'-azobisisobutyronitrile solution (solid content 2.5% by mass) dissolved in ethyl acetate was added to the mixture, and the mixture was held at 65°C for 10 hours while stirring. Next, the mixture was diluted with 98 parts by mass of ethyl acetate and filtered through a 200-mesh wire net to obtain an acrylic copolymer solution (2) with a weight average molecular weight of 1.6 million. Next, 100 parts by mass of the solid content of the acrylic copolymer solution (2) having a weight average molecular weight of 1.6 million was mixed and stirred with 5 parts by mass of polymerized rosin ester-based tackifier resin D-125 (Arakawa Chemical Industries, Ltd.) and 15 parts by mass of petroleum-based tackifier resin FTR6125 (Mitsui Chemicals, Inc.), and then the solid content concentration was adjusted to 31% by mass using ethyl acetate to obtain an acrylic adhesive composition (2). Next, 100 parts by mass of the acrylic adhesive composition (2) (solid content 31 parts by mass) and 1.3 parts by mass of a crosslinking agent (DIC Corporation, Burnock NC-40, isocyanate-based crosslinking agent, solid content 40% by mass, ethyl acetate solution) were mixed and mixed for 10 minutes using a dispersion stirrer to obtain adhesive (2).

[0114] [Preparation of Adhesive (3)] Resin composition (2) (a mixture of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer, the structural unit derived from styrene represented by the chemical formula (1) is 24% by mass, and the ratio of the styrene-isoprene copolymer to the total amount of the resin composition (2) is 67% by mass) 100 parts by mass of Quinton G115 (C 5 Series / C 9 A pressure-sensitive adhesive (3) was obtained by mixing 40 parts by mass of a tertiary ester resin (based petroleum resin, softening point 115°C), 30 parts by mass of Pencel D-160 (polymerized rosin ester resin manufactured by Arakawa Chemical Industries Co., Ltd., softening point 150°C to 165°C), 5 parts by mass of Nippon Oil Polybutene HV-50 (polybutene manufactured by JX Nippon Oil & Energy Corporation, pour point -12.5°C), and 1 part by mass of an antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) and dissolving the mixture in 100 parts by mass of toluene as a solvent.

[0115] [Preparation of Adhesive (4)] Resin composition (1) (a mixture of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer, the structural unit derived from styrene represented by the chemical formula (1) is 25% by mass, and the ratio of the styrene-isoprene copolymer to the total amount of the resin composition 1 is 17% by mass) 100 parts by mass of Quinton G115 (C 5 Series / C 9A pressure-sensitive adhesive (4) was obtained by mixing 16 parts by mass of a tertiary ester resin (based petroleum resin, softening point 115°C), 12 parts by mass of Pencel D-160 (polymerized rosin ester resin manufactured by Arakawa Chemical Industries Co., Ltd., softening point 150°C to 165°C), 2 parts by mass of Nippon Oil Polybutene HV-50 (polybutene manufactured by JX Nippon Oil & Energy Corporation, pour point -12.5°C), and 1 part by mass of an antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) and dissolving the mixture in 100 parts by mass of toluene as a solvent.

[0116] [Preparation of Adhesive (5)] 100 parts by mass of the resin composition (1), Quinton G115 (C manufactured by Zeon Corporation) 5 Series / C 9 A pressure-sensitive adhesive (5) was obtained by mixing 8 parts by mass of a tertiary ester resin (based petroleum resin, softening point 115°C), 6 parts by mass of Pencel D-160 (polymerized rosin ester resin manufactured by Arakawa Chemical Industries Co., Ltd., softening point 150°C to 165°C), 1 part by mass of Nippon Oil Polybutene HV-50 (polybutene manufactured by JX Nippon Oil & Energy Corporation, pour point -12.5°C), and 1 part by mass of an antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) and dissolving the mixture in 100 parts by mass of toluene as a solvent.

[0117] [Preparation of Adhesive (6)] 100 parts by mass of the resin composition (1), Quinton G115 (C manufactured by Zeon Corporation) 5 Series / C 9 A pressure-sensitive adhesive (6) was obtained by mixing 24 parts by mass of a tertiary ester resin (based petroleum resin, softening point 115°C), 18 parts by mass of Pencel D-160 (polymerized rosin ester resin manufactured by Arakawa Chemical Industries Co., Ltd., softening point 150°C to 165°C), 3 parts by mass of Nippon Oil Polybutene HV-50 (polybutene manufactured by JX Nippon Oil & Energy Corporation, pour point -12.5°C) and 1 part by mass of an antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) and dissolving the mixture in 100 parts by mass of toluene as a solvent.

[0118] [Preparation of Adhesive (7)] 100 parts by mass of the resin composition (2), Quinton G115 (C manufactured by Zeon Corporation) 5 Series / C 9 A pressure-sensitive adhesive (7) was obtained by mixing 16 parts by mass of a tertiary ester resin (based petroleum resin, softening point 115°C), 12 parts by mass of Pencel D-160 (polymerized rosin ester resin manufactured by Arakawa Chemical Industries Co., Ltd., softening point 150°C to 165°C), 2 parts by mass of Nippon Oil Polybutene HV-50 (polybutene manufactured by JX Nippon Oil & Energy Corporation, pour point -12.5°C) and 1 part by mass of an antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) and dissolving the mixture in 100 parts by mass of toluene as a solvent.

[0119] [Preparation of Adhesive (8)] 100 parts by mass of SK Dyne 909A (manufactured by Soken Chemical & Engineering Co., Ltd., acrylic adhesive, solid content 24.5% by mass), 1 part by mass of MA220 (manufactured by Mitsubishi Chemical, carbon black), and 0.7 parts by mass of Coronate L-45 (manufactured by Nippon Polyurethane Industry Co., Ltd., isocyanate crosslinking agent, solid content 45% by mass) were mixed and stirred for 15 minutes to prepare an adhesive (8).

[0120] [Preparation of Adhesive (9)] Resin composition (4) (a mixture of a styrene-isoprene copolymer and a styrene-isoprene-styrene copolymer, the structural unit derived from styrene represented by the chemical formula (1) is 15% by mass, and the ratio of the styrene-isoprene copolymer to the total amount of the resin composition 4 is 78% by mass) 100 parts by mass of Quinton G115 (C 5 Series / C 9 A pressure-sensitive adhesive (9) was obtained by mixing 40 parts by mass of a tertiary ester resin (based petroleum resin, softening point 115°C), 30 parts by mass of Pencel D-160 (polymerized rosin ester resin manufactured by Arakawa Chemical Industries Co., Ltd., softening point 150°C to 165°C), 5 parts by mass of Nippon Oil Polybutene HV-50 (polybutene manufactured by JX Nippon Oil & Energy Corporation, pour point -12.5°C), and 1 part by mass of an antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) and dissolving the mixture in 100 parts by mass of toluene as a solvent.

[0121] Example 1 The pressure-sensitive adhesive (1) was applied onto a release liner using an applicator so that the thickness after drying would be 5 μm, and dried at 80° C. for 3 minutes to prepare a pressure-sensitive adhesive layer (1). The resin composition (1) was heat pressed (pressure 0.5 MPa, press plate temperature 130°C, press time 2 minutes) to prepare a substrate having a thickness of 200 μm. The adhesive layer (1) prepared above was attached to both sides of the substrate and laminated under pressure of 0.2 MPa to prepare an adhesive tape.

[0122] Example 2 An adhesive tape was produced in the same manner as in Example 1, except that the thickness of the resin composition (1) was 400 μm.

[0123] Example 3 An adhesive tape was produced in the same manner as in Example 1, except that the thickness of the resin composition (1) was set to 1000 μm.

[0124] Example 4 The resin composition (2) was heat pressed (pressure 0.5 MPa, press plate temperature 130°C, press time 2 minutes) to prepare a substrate having a thickness of 200 μm. The adhesive layer (1) prepared above was attached to both sides of the substrate, and the substrate was laminated under pressure of 0.2 MPa to prepare an adhesive tape.

[0125] Example 5 An adhesive tape was produced in the same manner as in Example 4, except that the thickness of the resin composition (2) was set to 1000 μm.

[0126] Example 6 The pressure-sensitive adhesive (1) was applied onto a release liner using an applicator so that the thickness after drying would be 25 μm, and dried at 80° C. for 3 minutes to prepare a pressure-sensitive adhesive layer (2). Next, the adhesive layer (2) prepared above was attached to both sides of a sheet-like resin composition (3) (ester-based polyurethane compound) having a thickness of 100 μm, and laminated under a pressure of 0.2 MPa to prepare an adhesive tape.

[0127] Example 7 The adhesive (2) was applied to the surface of a release liner using a bar coater so that the adhesive layer would have a thickness of 5 μm after drying, and then dried at 85° C. for 3 minutes to produce an adhesive layer (3). The resin composition (1) was heat pressed (pressure 0.5 MPa, press plate temperature 130°C, press time 2 minutes) to prepare a substrate having a thickness of 200 μm. The adhesive layer (3) prepared above was attached to both sides of the substrate, and the substrate was laminated under pressure of 0.2 MPa to prepare an adhesive tape.

[0128] Example 8 The adhesive (3) was applied onto release paper using an applicator so that the thickness after drying would be 5 μm, and dried at 80° C. for 3 minutes to prepare an adhesive layer (4). The resin composition (1) was heat pressed (pressure 0.5 MPa, press plate temperature 130°C, press time 2 minutes) to prepare a substrate having a thickness of 200 μm. The adhesive layer (4) prepared above was attached to both sides of the substrate, and the substrate was laminated under pressure of 0.2 MPa to prepare an adhesive tape.

[0129] Example 9 The pressure-sensitive adhesive (3) was applied onto a release liner using an applicator so that the thickness after drying would be 25 μm, and dried at 80° C. for 3 minutes to prepare a pressure-sensitive adhesive layer (5). Next, the resin composition (1) was heat pressed (pressure 0.5 MPa, press plate temperature 130°C, press time 2 minutes) to prepare a substrate having a thickness of 200 μm. The adhesive layer (5) prepared above was attached to both sides of the substrate, and the substrate was laminated under pressure of 0.2 MPa to prepare an adhesive tape.

[0130] Example 10 The pressure-sensitive adhesive (4) was applied onto a release paper using an applicator so that the thickness after drying would be 200 μm, and then dried at 80° C. for 3 minutes to prepare a pressure-sensitive adhesive tape.

[0131] Example 11 The pressure-sensitive adhesive (5) was applied onto a release paper using an applicator so that the thickness after drying would be 200 μm, and then dried at 80° C. for 3 minutes to prepare a pressure-sensitive adhesive tape.

[0132] Example 12 The pressure-sensitive adhesive (6) was applied onto a release paper using an applicator so that the thickness after drying would be 200 μm, and then dried at 80° C. for 3 minutes to prepare a pressure-sensitive adhesive tape.

[0133] Example 13 The pressure-sensitive adhesive (7) was applied onto a release paper using an applicator so that the thickness after drying would be 450 μm, and then dried at 80° C. for 3 minutes to prepare a pressure-sensitive adhesive tape.

[0134] Example 14 An adhesive tape was produced in the same manner as in Example 13, except that the thickness of the adhesive (7) was 750 μm.

[0135] Example 15 An adhesive tape was produced in the same manner as in Example 13, except that the thickness of the adhesive (7) was 300 μm.

[0136] Example 16 The pressure-sensitive adhesive (8) was applied onto a release liner using an applicator so that the thickness after drying would be 50 μm, and dried at 80° C. for 3 minutes to produce a pressure-sensitive adhesive layer (6). Resin composition (1) (a mixture of styrene-isoprene copolymer and styrene-isoprene-styrene copolymer, 25% by mass of the structural unit derived from styrene represented by the above chemical formula (1), and 17% by mass of the styrene-isoprene copolymer relative to the total amount of the above resin composition 1) was heat pressed (pressure 0.5 MPa, press plate temperature 130°C, press time 2 minutes) to prepare a substrate having a thickness of 250 μm. The above-prepared adhesive layer (6) was attached to both sides of this substrate, and the substrate was laminated under pressure of 0.2 MPa to prepare an adhesive tape.

[0137] Example 17 An adhesive tape was produced in the same manner as in Example 16, except that 1 part by mass of BLACK PEARLS 120 (carbon black, manufactured by Cabot Corporation) was blended into the resin composition (1).

[0138] Comparative Example 1 An adhesive tape was produced in the same manner as in Example 1, except that a PET film having a thickness of 188 μm was used as the substrate instead of the resin composition (1).

[0139] Comparative Example 2 The resin composition (4) was heat pressed (pressure 0.5 MPa, press plate temperature 130°C, press time 2 minutes) to prepare a substrate having a thickness of 200 μm. The adhesive layer (1) prepared above was attached to both sides of the substrate and laminated under pressure of 0.2 MPa to prepare an adhesive tape.

[0140] Comparative Example 3 The adhesive layer (1) prepared above was attached to both sides of the sheet-like resin composition 3 having a thickness of 100 μm, and laminated under a pressure of 0.2 MPa to prepare an adhesive tape.

[0141] Comparative Example 4 The pressure-sensitive adhesive (1) was applied onto a release liner with an applicator so that the thickness after drying would be 200 μm, and then dried at 65° C. for 10 minutes to prepare a pressure-sensitive adhesive tape.

[0142] Comparative Example 5 The pressure-sensitive adhesive (8) was applied onto a release paper using an applicator so that the thickness after drying would be 200 μm, and then dried at 65° C. for 10 minutes to prepare a pressure-sensitive adhesive tape.

[0143] Comparative Example 6 The pressure-sensitive adhesive (3) was applied onto a release liner with an applicator so that the thickness after drying would be 200 μm, and then dried at 80° C. for 3 minutes to prepare a pressure-sensitive adhesive tape.

[0144] Comparative Example 7 An adhesive tape was produced in the same manner as in Example 1, except that the thickness of the resin composition (1) was 100 μm.

[0145] The pressure-sensitive adhesive tapes, substrates, and pressure-sensitive adhesive layers prepared in Examples 1 to 17 and Comparative Examples 1 to 7 were tested by the methods described below, and the evaluation results are shown in Tables 1 and 2.

[0146] [Stress at break, elongation at break, stress at 25% elongation, stress at 50% elongation of adhesive tape, substrate, and adhesive] The stress at break, elongation at break, stress at 25% elongation, and stress at 50% elongation of the adhesive tape were measured by punching out the adhesive tape into a dumbbell shape with a gauge length of 20 mm and a width of 10 mm, and pulling it in the lengthwise direction at a tensile speed of 300 mm / min using a Tensilon tensile testing machine under measurement atmosphere conditions of 23°C and 50% RH.

[0147] [Storage modulus E' of adhesive tape and substrate] The pressure-sensitive adhesive tapes obtained in the Examples and Comparative Examples were punched out using a dumbbell cutter into the shape of a JIS K 7127 test piece type 5 to prepare test pieces. The test piece was used for measurement using a dynamic viscoelasticity measuring device RSA-II (manufactured by Rheometrics, Inc.) (frequency 1 Hz, heating rate 3° C. / min) to obtain a storage modulus E′ at 23° C.

[0148] [Storage modulus G' of adhesive layer] The storage modulus G' in the present invention is a value measured by sandwiching a viscoelastic tester, Ares 2kSTD manufactured by Rheometrics, between parallel plates having a diameter of 7.9 mm, and at a frequency of 1 Hz, using a pressure sensitive adhesive laminated to a thickness of 2 mm as a test piece.

[0149] [180° peel adhesive strength] A 20 mm wide adhesive tape sample was attached to a stainless steel plate at 23°C and pressed with a 2 kg roller once. After leaving it to stand at 23°C for 1 hour, it was pulled in a 180° direction at a pulling speed of 300 mm / min using a Tensilon tensile tester to measure the adhesive strength.

[0150] [Method of evaluating holding power] One adhesive surface of the adhesive tape was backed with a 25 μm thick polyethylene terephthalate film, and the tape was cut to a size of 20 mm wide x 100 mm long. The tape was then placed on the surface of a clean, smooth stainless steel plate (hairline polished with #360 waterproof abrasive paper) in an atmosphere of 23°C and 50% RH so that the adhesive area was 20 mm x 20 mm. A 2 kg roller was rolled back and forth over the top surface of the plate to press them together, and the tape was left to stand for 1 hour in an environment of 23°C to prepare a test specimen. With the stainless steel plate constituting the test piece fixed, a load of 1 kg was applied to the adhesive tape in an environment of 70° C., and the time until the adhesive tape fell from the stainless steel plate was measured. If the adhesive tape did not fall after 24 hours or more, it was recorded as “>24”.

[0151] [Method of evaluating shear adhesive strength] The adhesive tape was cut to a size of 20 mm width x 20 mm length and attached to the surface of a clean, smooth-surfaced stainless steel plate 1 (hairline polished with No. 360 waterproof abrasive paper) in an atmosphere of 23°C and 50% RH so that the adhesion area was 20 mm x 20 mm, and the opposite side was attached to the surface of a clean, smooth-surfaced stainless steel plate 2 (hairline polished with No. 360 waterproof abrasive paper) so that the adhesion area was 20 mm x 20 mm. After that, they were pressed together by rolling them back and forth once with a 5 kg roller, and left in an environment of 23°C for 24 hours to prepare a test specimen. With the stainless steel plate 1 constituting the test piece fixed, the stainless steel plate 2 was pulled in the shear direction of the adhesive tape at a speed of 300 mm / min using a Tensilon tensile tester in an atmosphere of 23°C and 50% RH to measure the shear adhesive strength.

[0152] [Method for evaluating splitting adhesive strength] The adhesive tape was cut to a size of 20 mm width x 20 mm length and attached to the surface of a clean, smooth aluminum plate 1 (A1050) in an atmosphere of 23°C and 50% RH so that the adhesion area was 20 mm x 20 mm. The opposite side was attached to the surface of a clean, smooth aluminum plate 2 (A1050) in an area of ​​20 mm x 20 mm, and then the two were pressed together by rolling them back and forth with a 5 kg roller. The test pieces were then left to stand in an environment of 23°C for 24 hours to prepare test pieces. With the aluminum plate 1 constituting the test piece fixed, the aluminum plate 2 was pulled in the cleavage direction of the adhesive tape at a speed of 300 mm / min using a Tensilon tensile tester in an atmosphere of 23°C and 50% RH to measure the cleavage adhesive strength.

[0153] [Removability] The adhesive tape, 10 mm wide x 60 mm long, was attached to a clean, smooth-surfaced stainless steel plate with a 10 mm wide x 10 mm long grip protruding from it, and then the other side was attached to a clean, smooth-surfaced stainless steel plate and pressed with a roller once while applying a load of 2 kg to prepare a test piece. After attachment, the tape was left for 3 days in an atmosphere of 23°C and 50% RH, and the grip part of the adhesive tape was stretched by hand at a speed of approximately 300 mm / min in the horizontal direction of the adhesive tape at 23°C and 50% RH. The test was conducted three times, and the degree of breakage of the adhesive tape and the degree of adhesive remaining on the adherend after the adhesive tape was peeled off were visually evaluated according to the following criteria.

[0154] (evaluation) ◎: The film was peeled off cleanly all three times. ○: The tape was peeled off cleanly twice, but broke once. The area of ​​the adhesive tape that remained without stretching was 1 / 5 or less of the initial applied area. △: The tape was peeled off cleanly twice, but broke once. The area of ​​the adhesive tape that remained without stretching was 1 / 5 or more of the initial applied area. ×: The adhesive tape could not be peeled off, or the tape broke two or more times.

[0155] [Rigid body following] The adhesive tape, 20 mm wide x 20 mm long, was attached to a transparent acrylic plate, 30 mm wide x 30 mm long, and then another transparent acrylic plate, 30 mm wide x 30 mm long, was attached to the other side of the adhesive tape to prepare a test piece. After attachment, the test piece was left for 24 hours in an atmosphere of 23°C and 50% RH, and the ratio of the area where the adhesive tape and the acrylic plate were in close contact (attached area) to the area of ​​the adhesive tape was evaluated by visual inspection through the acrylic plate.

[0156] (evaluation) ◎: The application area is 100-60% of the adhesive tape area ○: The adhesive area is 60-40% of the adhesive tape area △: The applied area is 40-30% of the adhesive tape area ×: The applied area is less than 30% of the adhesive tape area.

[0157] [Table 1]

[0158] [Table 2]

[0159] [Table 3]

[0160] [Table 4]

[0161] The above results show that in Examples 1 to 17 of the present invention, all of them had excellent adhesion and conformability to hard adherends, and could be easily peeled off without leaving any adhesive residue by stretching the pressure-sensitive adhesive tape horizontally, and had excellent removability. On the other hand, Comparative Examples 1 to 7 were unable to simultaneously satisfy the above-mentioned adhesion, conformability, and removability.

Claims

1. The adhesive tape has an adhesive layer on at least one surface of a substrate and is stretchable and peelable. The thickness of the adhesive tape is greater than 150 μm and less than 1500 μm, the material constituting the substrate is a styrene-based resin or a polyurethane-based resin, The storage modulus E' (23°C) of the substrate is 1.41 × 10 ６ ~1.12 x 10 ７ Pa, The adhesive tape has a breaking elongation of 600 to 3000%, The adhesive tape has a breaking stress of 2.5 to 80.0 MPa; The stress at 50% elongation of the pressure-sensitive adhesive tape is 110 to 160% of the stress at 25% elongation, The elongation at break and the stress at break are values ​​measured by punching out the adhesive tape into a dumbbell shape having a gauge length of 20 mm and a width of 10 mm, and pulling the adhesive tape in the length direction at a tensile speed of 300 mm / min using a Tensilon tensile tester under measurement atmosphere conditions of 23°C and 50% RH.

2. 2. The pressure-sensitive adhesive tape according to claim 1, wherein the stress at 25% elongation of the pressure-sensitive adhesive tape is 0.05 to 10 MPa.

3. The pressure-sensitive adhesive tape according to any one of claims 1 to 2, wherein the pressure-sensitive adhesive tape has a 180° peel adhesive strength of 5 N / 20 mm or more.

4. The adhesive tape according to any one of claims 1 to 3, wherein the thickness of the adhesive layer relative to the thickness of the substrate (adhesive layer / substrate) is 1 / 2 to 1 / 500.

5. The adhesive tape according to any one of claims 1 to 4, wherein the adhesive layer contains a filler.

6. The adhesive tape according to claim 5 , wherein the filler is carbon.

7. The adhesive tape has a splitting adhesive strength of 320 N / 4 cm ２ The pressure-sensitive adhesive tape according to any one of claims 1 to 6, wherein

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