Adhesive tapes and adhesives

Abstract

To provide a pressure sensitive adhesive tape and a pressure sensitive adhesive each having excellent adhesive force particularly to a polyolefin-based foam.SOLUTION: A pressure sensitive adhesive tape is provided, having a pressure sensitive adhesive layer containing a styrene-isoprene block copolymer (A) and a tackifying resin (B), wherein the styrene-isoprene block copolymer (A) contains a styrene-isoprene diblock copolymer (a1) and a styrene-isoprene triblock copolymer (a2), a content of the tackifying resin (B) is 75 pts.mass or more with respect to 100 pts.mass of the styrene-isoprene block copolymer (A), the tackifying resin (B) contains a petroleum resin (b1) and a rosin-based resin (b2), and a blending ratio (b1:b2) of the petroleum resin (b1) to the rosin-based resin (b2) is within a range of 2:1 to 10:1. A pressure sensitive adhesive enabling formation of the pressure sensitive adhesive layer is also provided.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an adhesive and an adhesive tape that can be used to fasten components that constitute, for example, electronic devices. [Background technology]

[0002] Rubber-based pressure-sensitive adhesives containing styrene-isoprene block copolymers have good initial adhesive strength to adherends such as polyethylene and polypropylene, and are therefore suitable for use, for example, in fastening components constituting electronic devices and interior and exterior components of automobiles.

[0003] For example, Patent Document 1 discloses an adhesive tape using a rubber-based adhesive, such as a double-sided adhesive tape having rubber-based adhesive layers on both sides of a substrate, the rubber-based adhesive layers being made of a styrene-based resin and a specified tackifier resin.

[0004] Although the double-sided adhesive tape is disclosed as being capable of exhibiting good adhesion to members containing polyolefin resins, there is still room for further improvement in adhesion. In particular, when bonding foam members or rigid members, which tend to disperse stress, it is difficult to apply sufficient pressure during bonding, making it difficult to obtain sufficient adhesion between the adhesive tape and the member, and there is concern about poor adhesion such as the tendency for interfacial peeling to occur between the adhesive tape and the member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2019-52280 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide an adhesive tape and an adhesive having excellent adhesive strength to adherends containing polyolefin resins such as polyethylene and polypropylene, particularly polyolefin foams. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention provides a pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer comprising a styrene-isoprene block copolymer (A) and a tackifier resin (B), wherein the styrene-isoprene block copolymer (A) contains a styrene-isoprene diblock copolymer (a1) and a styrene-isoprene triblock copolymer (a2), the content of the tackifier resin (B) is 75 parts by mass or more per 100 parts by mass of the styrene-isoprene block copolymer (A), the tackifier resin (B) contains a petroleum resin (b1) and a rosin-based resin (b2), and the blending ratio (b1:b2) of the petroleum resin (b1) to the rosin-based resin (b2) is within the range of 2:1 to 10:1.

[0008] The present invention also provides a pressure-sensitive adhesive capable of forming the pressure-sensitive adhesive layer. Effect of the Invention

[0009] The pressure-sensitive adhesive tape and pressure-sensitive adhesive of the present invention have excellent adhesive strength to adherends containing polyolefin resins such as polyethylene and polypropylene, in particular to polyolefin foams. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The pressure-sensitive adhesive tape of the present invention has a pressure-sensitive adhesive layer having a predetermined composition. The pressure-sensitive adhesive tape of the present invention and the pressure-sensitive adhesive used in forming the pressure-sensitive adhesive layer will be described below.

[0011] 1. Adhesive layer The adhesive layer of the adhesive tape of the present invention is composed of an adhesive containing a styrene-isoprene block copolymer (A) containing a styrene-isoprene diblock copolymer (a1) and a styrene-isoprene triblock copolymer (a2), and a tackifier resin (B). The adhesive layer and the adhesive constituting the adhesive layer in the present invention are characterized in that the content of the tackifier resin (B) is 75 parts by mass or more per 100 parts by mass of the styrene-isoprene block copolymer (A). The tackifier resin (B) is further characterized in that it contains a petroleum resin (b1) and a rosin-based resin (b2), and the compounding ratio (b1:b2) of the petroleum resin (b1) to the rosin-based resin (b2) is within the range of 2:1 to 10:1.

[0012] The pressure-sensitive adhesive layer and the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer contain a specific tackifier resin (B) in a predetermined blend amount together with a specific styrene-based resin (A), thereby enabling the layer to exhibit high adhesive (cohesive) strength to adherends primarily composed of polyolefin-based resins, in particular polyolefin-based foams which tend to dissipate stress and for which sufficient adhesion is difficult to obtain.

[0013] Furthermore, by having the specific composition described above, the adhesive layer and the adhesive constituting the adhesive layer not only have high adhesion to polyolefin foams, but also are less likely to undergo interfacial peeling over time, even when used in an environment exposed to heat, can exhibit high holding power, and have excellent thermal durability.

[0014] -Styrene-isoprene block copolymer (A)- The styrene-isoprene block copolymer (A) contained in the pressure-sensitive adhesive layer and the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer in the present invention has a structural unit represented by the following chemical formula (1). Specifically, the structural unit is preferably a structure derived from styrene.

[0015] The styrene-isoprene block copolymer (A) preferably has a structural unit represented by the following chemical formula (1) in the range of 10% by mass to 80% by mass, more preferably 12% by mass to 60% by mass, even more preferably 15% by mass to 40% by mass, and even more preferably 17% by mass to 35% by mass, based on the total mass of the styrene-isoprene block copolymer (A). This is because a pressure-sensitive adhesive layer can be obtained that has high adhesion to adherends mainly composed of polyolefin resins such as polyolefin materials and polyester materials, especially polyolefin foams, and can exhibit even better initial adhesion. In addition, the pressure-sensitive adhesive layer can be obtained that has excellent heat durability.

[0016]

number

[0017] The amount of the structural unit refers to the mass ratio of the structure represented by the above formula (1) to the total mass of the styrene-isoprene block copolymer (A).

[0018] In the present invention, the styrene-isoprene block copolymer (A) contains the styrene-isoprene diblock copolymer (a1) and the styrene-isoprene triblock copolymer (a2). The styrene-isoprene block copolymer (A) is preferably a mixture of the styrene-isoprene diblock copolymer (a1) and the styrene-isoprene triblock copolymer (a2). The styrene-isoprene block copolymer (A), which is a mixture of the (a1) and (a2), can be produced by a method of separately producing the (a1) and (a2) and then mixing them, or by a method of separately polymerizing styrene and isoprene to produce polystyrene and polyisoprene, and then reacting them to obtain a mixture of the (a1) and (a2).

[0019] The proportion of the styrene-isoprene diblock copolymer (a1) relative to the total amount of the styrene-isoprene block copolymer (A) is preferably in the range of 10% by mass to 80% by mass, more preferably in the range of 15% by mass to 75% by mass, even more preferably in the range of 20% by mass to 70% by mass, and still more preferably in the range of 25% by mass to 65% by mass. In addition, in the mixture of the styrene-isoprene block copolymer (A) consisting of the styrene-isoprene diblock copolymer (a1) and the styrene-isoprene triblock copolymer (a2), the styrene-isoprene block copolymer (A) preferably contains the styrene-isoprene diblock copolymer (a1) in the range of 10% by mass to 80% by mass, more preferably 15% by mass to 75% by mass, more preferably 20% by mass to 70% by mass, and even more preferably 25% by mass to 65% by mass, based on the total mass of the styrene-isoprene diblock copolymer (a1) and the styrene-isoprene triblock copolymer (a2). This is because the pressure-sensitive adhesive layer has high adhesion to adherends mainly composed of polyolefin resins such as polyolefin materials and polyester materials, especially polyolefin foams, and can exhibit even better initial adhesion. In addition, the pressure-sensitive adhesive layer has excellent heat durability.

[0020] In addition, as the styrene-isoprene block copolymer (A), it is preferable to use one having 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, while having good workability in the manufacturing process, it is more preferable to obtain an adhesive layer that has excellent adhesion and high initial adhesion to an adherend mainly composed of a polyolefin resin, especially a polyolefin foam, and further has excellent heat durability.

[0021] The styrene-isoprene block copolymer (A) 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 different structures. When a styrene-based 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 in a mixture according to the required properties.

[0022] The styrene-isoprene block copolymer (A) can be produced by a conventional method, such as a method of separately polymerizing styrene and isoprene to produce polystyrene and polyisoprene, and then reacting them, or a method of polymerizing styrene to obtain a polymer, and then reacting the polymer with isoprene.

[0023] -Tackifying resin (B)- The tackifier resin (B) used in the adhesive layer and the adhesive constituting the adhesive layer in the present invention is characterized in that it contains a petroleum resin (b1) and a rosin-based resin (b2), and the blending ratio (b1:b2) of the petroleum resin (b1) and the rosin-based resin (b2) is within the range of 2:1 to 10:1. The content of the tackifier resin (B) is 75 parts by mass or more per 100 parts by mass of the styrene-isoprene block copolymer (A). This allows for a pressure-sensitive adhesive layer that has high adhesion to adherends mainly composed of polyolefin resins, especially polyolefin foams, and can exhibit even better initial adhesion, when used in combination with the specific styrene-based resin (A) described above.

[0024] The tackifier resin (B) may have a compounding ratio (b1:b2) of the petroleum resin (b1) to the rosin resin (b2) in the range of 2:1 to 10:1, preferably in the range of 3:1 to 8:1, more preferably in the range of 3:1 to 6:1, and even more preferably in the range of 4:1 to 6:1. This is because it can increase the adhesive strength to an adherend mainly composed of a polyolefin resin, especially a polyolefin foam. The compounding ratio (b1:b2) of the petroleum resin (b1) to the rosin resin (b2) is a mass ratio.

[0025] The content of the tackifier resin (B) contained in the adhesive layer and the adhesive constituting the adhesive layer may be 75 parts by mass or more relative to 100 parts by mass of the styrene-isoprene block copolymer (A), and is preferably used in the range of 80 parts by mass to 200 parts by mass, more preferably used in the range of 90 parts by mass to 180 parts by mass, and even more preferably used in the range of 100 parts by mass to 160 parts by mass. By setting the blending amount of the tackifier resin (B) relative to 100 parts by mass of the styrene-isoprene block copolymer (A) within the above range, it is possible to obtain an adhesive layer that has high adhesion to an adherend mainly composed of a polyolefin resin, especially a polyolefin foam, and can exhibit even better initial adhesion. In addition, it is possible to obtain an adhesive layer that has excellent heat durability.

[0026] =Petroleum resin(b1)= The softening point of the petroleum resin (b1) is preferably 80°C or higher, more preferably in the range of 80°C to 160°C, more preferably in the range of 90°C to 150°C, and more preferably in the range of 100°C to 130°C from the viewpoint of better adhesion and better heat resistance. When the softening point of the petroleum resin (b1) is in the above range, the adhesiveness can be improved while maintaining the cohesive force of the adhesive layer and the adhesive constituting the adhesive layer, and therefore better adhesiveness can be exhibited to an adherend mainly composed of a polyolefin resin, especially a polyolefin foam. The softening point refers to a value measured by the method (dry bulb method) specified in JISK2207.

[0027] As the petroleum resin (b1), it is preferable to use one that is solid at room temperature (23°C), and petroleum resins such as aliphatic petroleum resins, aromatic petroleum resins, aliphatic-aromatic copolymer petroleum resins, hydrogenated products thereof (e.g. alicyclic petroleum resins, aliphatic-alicyclic petroleum resins), coumarone resins, and coumarone-indene resins can be used. Among them, it is preferable that the petroleum resin (b1) is at least one selected from the group consisting of aliphatic petroleum resins, aromatic petroleum resins, and aliphatic-aromatic copolymer petroleum resins. This is because it has high compatibility with the styrene-isoprene block copolymer (A) and can exhibit excellent adhesion to adherends mainly composed of polyolefin resins, especially polyolefin foams. In addition, it is because the pressure-sensitive adhesive can ensure excellent storage stability in solution before the pressure-sensitive adhesive layer is formed.

[0028] As the pre-aliphatic petroleum resin, C5-based petroleum resins obtained from pentene, pentadiene, isoprene, etc. can be preferably used. For example, Escoretz 1202, 1304, 1401 (manufactured by Tonen Chemical Co., Ltd.), Wingtack 95 (manufactured by The Goodyear Tire & Rubber Company), Quinton K100, R100, F100 (manufactured by Zeon Corporation), Picotack 95, Picopal 100 (manufactured by Rika Hercules), etc. can be used.

[0029] As the aromatic petroleum resin, C9 petroleum resins obtained from indene, methylindene, vinyltoluene, styrene, α-methylstyrene, β-methylstyrene, and the like can be preferably used.

[0030] As the aliphatic / aromatic copolymer petroleum resin, a C5 / C9 petroleum resin which is a copolymer of the above-mentioned C5 petroleum resin and C9 petroleum resin can be preferably used. For example, Escoretz 2101 (manufactured by Tonex), Quinton G115 (manufactured by Zeon Corporation), Hercotac 1149 (manufactured by Rika Hercules Corporation), etc. can be used.

[0031] The alicyclic petroleum resin can be obtained by hydrogenating the above-mentioned C9 petroleum resin, and examples of such resins that can be used include Escoretz 5300 (manufactured by Tonex), Alcon P-100 (manufactured by Arakawa Chemical Industries), and Regalite R101 (manufactured by Rika Finetech).

[0032] The petroleum resin (b1) in the pressure-sensitive adhesive layer and in the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be contained alone or in combination of two or more kinds.

[0033] The petroleum resin (b1) is preferably contained in the largest amount in the tackifier resin (B) while satisfying the blending ratio with the rosin resin (b2), and the content of the petroleum resin (b1) is preferably 60 mass% or more, more preferably 75 mass% or more, and even more preferably 80 mass% or more, of the total amount (100 mass%) of the tackifier resin (B). By containing the petroleum resin (b1), which has high compatibility with the styrene-isoprene block copolymer (A), in the above-mentioned range, excellent adhesion can be exhibited to adherends mainly composed of polyolefin resins, especially polyolefin foams. Furthermore, before the pressure-sensitive adhesive layer is formed, the pressure-sensitive adhesive can ensure excellent storage stability in solution.

[0034] = Rosin-based resin (b2) = Examples of the rosin resin (b2) include resins having a rosin skeleton, such as rosin resin, unsaturated acid-modified rosin modified with unsaturated acids such as (meth)acrylic acid, fumaric acid, and maleic acid, rosin phenol modified with phenols such as phenol and alkylphenol, disproportionated rosin resin obtained by disproportionating rosin resin, and polymerized rosin resin obtained by polymerizing rosin resin; rosin ester resin which is an ester of the above rosin resin and alcohol; hydrogenated rosin resin or hydrogenated rosin ester resin obtained by hydrogenating rosin resin or rosin ester resin; etc. Among them, polymerized rosin resin is preferred in that it enhances the cohesive force of the pressure-sensitive adhesive layer and exhibits excellent adhesive performance to adherends mainly composed of polyolefin resin, especially polyolefin foam.

[0035] The rosin resin (b2) preferably has a softening point of 80° C. or higher, more preferably in the range of 90° C. to 200° C., more preferably in the range of 100° C. to 180° C., and even more preferably in the range of 110° C. to 160° C. When the rosin resin (b2) has a softening point within the above range, the adhesive layer has an increased cohesive force and exhibits excellent adhesive performance to adherends mainly composed of polyolefin resins, especially polyolefin foams. The softening point refers to a value measured by the method (dry bulb method) specified in JIS K2207.

[0036] The rosin-based resin (b2) in the pressure-sensitive adhesive layer and in the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer may be contained alone or in combination of two or more kinds.

[0037] =Other tackifying resins (b3)= The adhesive layer and the adhesive constituting the adhesive layer in the present invention contain at least a petroleum resin (b1) and a rosin-based resin (b2) as a tackifier resin (B), but may contain a resin (b3) other than the resin (b1) and the resin (b2). Examples of the resin (b3) include known tackifier resins, such as terpene resins, phenolic resins, and ketone resins. The content of the resin (b3) is preferably 20% by mass or less of the total amount (100% by mass) of the tackifier resin (B), more preferably 10% by mass or less, and even more preferably 1% by mass or less, and particularly preferably 0% by mass, i.e., the tackifier resin (B) is substantially composed of one or more petroleum resins (b1) and one or more rosin-based resins (b2).

[0038] -Optional ingredients- In addition to the above-mentioned components, the adhesive layer of the present invention and the adhesive constituting the adhesive layer may contain, as necessary, other polymer components, crosslinking agents, additives such as antioxidants, UV absorbers, fillers, pigments, thickeners, etc. that can be generally used in adhesives, within the range that does not impair the effects of the present invention. Among them, it is preferable to contain an antioxidant in order to further improve heat durability.

[0039] As the antiaging agent, for example, it is preferable to use a phenol-based antiaging agent, since this can effectively improve the heat resistance stability of the styrene-isoprene block copolymer (A), 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.

[0040] The above-mentioned 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.

[0041] The phenol-based anti-aging agent is preferably used in a range of 0.1 parts by mass to 5 parts by mass per 100 parts by mass of the styrene-isoprene block copolymer (A). 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 block copolymer, and as a result, a pressure-sensitive adhesive and pressure-sensitive adhesive tape can be obtained that maintain good initial adhesion and have even better heat durability.

[0042] The antioxidant may be a combination of the phenolic antioxidant and other antioxidants such as phosphorus-based antioxidants (also called processing stabilizers), amine-based antioxidants, and imidazole-based antioxidants, and in particular, the combination of the phenolic antioxidant and phosphorus-based antioxidant can maintain good initial adhesion and obtain an adhesive and adhesive tape with even better heat durability. Note that the phosphorus-based antioxidant may slightly discolor (yellowing) over time in a high-temperature environment, so the amount of the antioxidant used is preferably set appropriately in consideration of the balance between the initial adhesion, heat durability, and discoloration prevention.

[0043] -Adhesive layer- The adhesive layer used in the present invention preferably has a thickness of 5 μm to 300 μm after drying, and more preferably has a thickness of 10 μm to 200 μm in order to obtain an adhesive tape having even better initial adhesive strength to an adherend mainly composed of a polyolefin resin, in particular a polyolefin foam.

[0044] 2.Other -Composition and properties of adhesive tape- The adhesive tape of the present invention may have the above-mentioned adhesive layer, and specific embodiments include a single-sided adhesive tape or double-sided adhesive tape in which an adhesive layer is laminated directly or via another layer on one or both sides of a substrate (core), and a so-called substrate-less double-sided adhesive tape consisting only of an adhesive layer.

[0045] The substrate may be any known material, such as plastic films, such as polyester films, polypropylene films, polyethylene films, polyimide films, etc., foams, such as urethane, polyethylene, and rubber-based foams, nonwoven fabrics, cloth, metal foils, paper, etc. Among these, the use of nonwoven fabrics is preferred, since it improves adhesion to the uneven surface of the adherend, thereby enabling the production of a pressure-sensitive adhesive tape that can exhibit excellent initial adhesive strength.

[0046] The nonwoven fabric may preferably be made of fibers such as pulp, rayon, Manila hemp, acrylonitrile, nylon, polyester, etc. In order to improve the tensile strength, the nonwoven fabric may be subjected to a treatment such as impregnation treatment using a thermoplastic resin such as viscose as a binder.

[0047] The nonwoven fabric has a basis weight of 5 g / m 2 ~150g / m 2 It is preferable to use a material having a thickness in the range of 10 g / m 2 ~100g / m 2 It is more preferable to use a material having a thickness in the range of 15 g / m 2 ~50g / m 2It is more preferable to use one in the range since the tensile strength of the adhesive tape can be improved and the ease of application can be improved.

[0048] The above-mentioned substrate is preferably 10 μm to 300 μm thick, more preferably 30 μm to 200 μm thick, and more preferably 50 μm to 150 μm thick, since this improves the tensile strength of the adhesive tape and improves the ease of application.

[0049] The pressure-sensitive adhesive tape of the present invention may have a release liner on the surface of the pressure-sensitive adhesive layer. As the release liner, any known release liner can be used.

[0050] The pressure-sensitive adhesive tape of the present invention preferably has a total thickness in the range of 10 μm to 400 μm, and more preferably has a total thickness in the range of 50 μm to 300 μm in order to obtain a pressure-sensitive adhesive tape with even better initial adhesive strength. Note that the total thickness of the pressure-sensitive adhesive tape does not include the thickness of the release liner.

[0051] The pressure-sensitive adhesive tape of the present invention can be used in the form of a product such as a sheet or a roll.

[0052] When the pressure-sensitive adhesive tape of the present invention is measured for its T-peel adhesive strength to a polyolefin foam by the following measurement method, it is preferable that the polyolefin foam undergoes material failure and peels off. Moreover, the pressure-sensitive adhesive tape of the present invention preferably has a T-peel adhesive strength to a polyolefin foam measured under the following measurement conditions of 15 (N / 20 mm) or more, more preferably 18 (N / 20 mm) or more, and even more preferably 20 (N / 20 mm) or more. This is because the pressure-sensitive adhesive tape can exhibit excellent adhesive strength to adherends mainly composed of polyolefin resins, particularly polyolefin foams.

[0053] (Measurement method) A polyolefin foam adherend was attached to both sides of the adhesive tape cut to 20 mm wide x 100 mm long, and then the top surface was pressed by rolling a 2 kg roller back and forth once, and left in an environment at 60°C for 24 hours to prepare a test piece. In an environment at 23°C, one end of the adherend of one of the test pieces was fixed to the lower chuck of the tension device of a Tensilon tensile tester, and one end of the other adherend was fixed to the upper chuck of the tension device of the Tensilon tensile tester, and the upper chuck was pulled at a speed of 50 mm / min to measure the T-peel adhesive strength.

[0054] To describe the measurement method in more detail, the T-peel adhesive strength of the adhesive tape can be measured by cutting the adhesive tape to a width of 20 mm and a length of 100 mm, laminating polyethylene (PE) foam as an adherend to both sides of the adhesive tape in an atmosphere of 23°C and 50% RH with one reciprocating pressure roller of a 2 kg roller, and then leaving the adhesive tape and the PE foam in an environment of 60°C for 24 hours to bring the adhesive tape and the PE foam into close contact with each other, and fixing one end of the adherend of one of the test pieces to the lower chuck of the tension device of a Tensilon tensile tester in an environment of 23°C and fixing the other end of the adherend to the upper chuck of the tension device of the Tensilon tensile tester, and pulling the upper chuck at a speed of 50 mm / min, thereby obtaining a measured adhesive strength (T-peel adhesive strength).

[0055] The adhesive tape of the present invention can exhibit high adhesive (sticky) strength, particularly to polyolefin foams, which tend to disperse stress and to which sufficient adhesion is difficult to obtain, but it can also exhibit high adhesive strength to a variety of adherends, not limited to polyolefin foams, that contain polyolefin resins as their main component.

[0056] In addition to the above-mentioned effects, the pressure-sensitive adhesive tape of the present invention can also exhibit excellent heat durability. More specifically, the pressure-sensitive adhesive tape of the present invention preferably has a drop-off time of 24 hours or more as measured by the following measurement method.

[0057] (Measurement method) One adhesive surface of the adhesive tape is backed with a 25 μm thick polyethylene terephthalate film, and the tape is cut to a size of 25 mm wide x 100 mm long. The tape is placed on the surface of a clean, smooth stainless steel plate (hairline polished with No. 360 waterproof abrasive paper) in an atmosphere of 23°C and 50% RH so that the adhesive area is 25 mm x 25 mm. A 2 kg roller is rolled back and forth over the top surface of the tape to press the tape together, and the tape is left in an environment of 23°C for 1 hour to prepare a test piece. With the stainless steel plate that constitutes the test piece fixed, a load of 0.5 kg is applied to the adhesive tape in an environment of 40°C, and the time from when the adhesive tape falls from the stainless steel plate is measured.

[0058] -Method of manufacturing adhesive tape- The manufacturing method of the pressure-sensitive adhesive tape of the present invention can be appropriately selected according to the lamination structure. For example, the manufacturing method includes a method of manufacturing by coating one or both sides of the above-mentioned substrate with an adhesive containing at least the above-mentioned styrene-isoprene block copolymer (A) and tackifier resin (B) and drying to form an adhesive layer, a method of manufacturing an adhesive layer by coating a release liner with the above-mentioned adhesive and drying it, and transferring it to one or both sides of the substrate, a method of manufacturing an adhesive layer by coating a release liner with the above-mentioned adhesive and drying it, and laminating another release liner on the surface of the above-mentioned adhesive layer, etc.

[0059] The pressure-sensitive adhesive contains a styrene-isoprene block copolymer (A) and a tackifier resin (B), the styrene-isoprene block copolymer (A) contains a styrene-isoprene diblock copolymer (a1) and a styrene-isoprene triblock copolymer (a2), the content of the tackifier resin (B) is 75 parts by mass or more per 100 parts by mass of the styrene-isoprene block copolymer (A), the tackifier resin (B) contains a petroleum resin (b1) and a rosin-based resin (b2), and the blending ratio (b1:b2) of the petroleum resin (b1) to the rosin-based resin (b2) is within the range of 2:1 to 10:1. Details of the composition of the pressure-sensitive adhesive are as described above in the section "1. Pressure-sensitive adhesive layer."

[0060] Examples of the method for applying the pressure-sensitive adhesive include a method using a roll coater, a die coater, or the like.

[0061] The pressure-sensitive adhesive may contain an organic solvent to ensure good coating workability. The type of the organic solvent is not particularly limited, and organic solvents commonly used for rubber-based pressure-sensitive adhesives and the like can be used. The organic solvent contained in the pressure-sensitive adhesive is preferably used in the range of 40 parts by mass to 400 parts by mass per 100 parts by mass of the total of the styrene-isoprene block copolymer (A) and the tackifier resin (B). The pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape is composed of the pressure-sensitive adhesive excluding the organic solvent.

[0062] -Applications- The pressure-sensitive adhesive tape of the present invention can be suitably used in the manufacturing of home appliances such as televisions, refrigerators, air conditioners, rice cookers, air purifiers, washing machines, vacuum cleaners, microwave ovens, personal computers, etc., and office automation equipment such as copiers, printers, etc. Specifically, the pressure-sensitive adhesive tape of the present invention can be used to fix components such as housings constituting the above-mentioned home appliances or office automation equipment to shock-absorbing or cushioning materials such as foams, felts, rubbers, etc., and to fix components such as the housings together, etc.

[0063] The components such as the housing may be made of, for example, polyolefin resin, polyester resin, etc. The shock-absorbing or cushioning material may be made of, for example, polyolefin foam, polyester foam, felt, nonwoven fabric, etc.

[0064] Examples of the shock-absorbing or cushioning material include anti-slip materials (grip members) that are placed between the home appliances or OA equipment and the installation surface such as a floor, and materials that suppress micro-vibrations of various parts.

[0065] The pressure-sensitive adhesive tape of the present invention can also be suitably used for fixing automobile interior components such as instrument panels, roof linings, and door trims to shock-absorbing or cushioning materials such as foams and felts.

[0066] Examples of the shock-absorbing or cushioning material include rubber materials for filling gaps in doors and windows, sound-absorbing materials, vibration-proofing materials, and anti-slip materials.

[0067] Furthermore, the pressure-sensitive adhesive tape of the present invention can also be suitably used for fixing, for example, the cushioned middle sole and upper member of sports shoes.

[0068] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and any embodiment that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included in the technical scope of the present disclosure. EXAMPLES

[0069] The present invention will now be described in more detail with reference to examples.

[0070] [Example 1] (Preparation of Adhesive A) 100 parts by mass of styrene-isoprene block copolymer composition (A1) (a mixture of styrene-isoprene diblock copolymer and styrene-isoprene triblock copolymer, 24% by mass of styrene-derived structural units represented by the above chemical formula (1), 40% by mass of styrene-isoprene diblock copolymer relative to the total amount of the above composition (A1)), 80 parts by mass of Quinton G115 (C5 / C9 petroleum resin manufactured by Nippon Zeon Co., Ltd., softening point 115°C) as tackifier resin (b1), 20 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) as tackifier resin (b2), and 1 part by mass of antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain adhesive A.

[0071] The above adhesive A was applied onto release paper using an applicator so that the thickness after drying would be 300 μm, and then dried at 80° C. for 5 minutes to prepare an adhesive tape A.

[0072] [Example 2] (Preparation of Adhesive B) 100 parts by mass of styrene-isoprene block copolymer composition (A1) (a mixture of styrene-isoprene diblock copolymer and styrene-isoprene triblock copolymer, 24% by mass of styrene-derived structural units represented by the above chemical formula (1), 40% by mass of styrene-isoprene diblock copolymer relative to the total amount of the above composition (A1)), 120 parts by mass of Quinton G115 (C5-based / C9-based petroleum resin manufactured by Nippon Zeon Co., Ltd., softening point 115°C) as tackifier resin (b1), 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) as tackifier resin (b2), and 1 part by mass of antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain adhesive B.

[0073] The above-mentioned adhesive B was applied onto a release paper using an applicator so that the thickness after drying would be 300 μm, and then dried at 80° C. for 5 minutes to prepare an adhesive tape B.

[0074] [Example 3] (Preparation of Adhesive C) Styrene-isoprene block copolymer composition (A2) (a mixture of styrene-isoprene diblock copolymer and styrene-isoprene triblock copolymer, 24% by mass of styrene-derived structural unit represented by the above chemical formula (1), 60% by mass of styrene-isoprene diblock copolymer to the total amount of the above composition (A2) 100 parts by mass, Quinton G115 (C5-based / C9-based petroleum resin manufactured by Nippon Zeon Co., Ltd., softening point 115 ° C.) as tackifier resin (b1) 80 parts by mass, Pencel D-160 (polymerized rosin ester resin manufactured by Arakawa Chemical Industries Co., Ltd., softening point 150 ° C. to 165 ° C.) as tackifier resin (b2) 20 parts by mass, and 1 part by mass of antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain adhesive C.

[0075] The above pressure-sensitive adhesive C was applied onto a release paper using an applicator so that the thickness after drying would be 300 μm, and then dried at 80° C. for 5 minutes to prepare a pressure-sensitive adhesive tape C.

[0076] [Example 4] (Preparation of Adhesive D) 100 parts by mass of styrene-isoprene block copolymer composition (A2) (a mixture of styrene-isoprene diblock copolymer and styrene-isoprene triblock copolymer, 24% by mass of styrene-derived structural units represented by the above chemical formula (1), 60% by mass of styrene-isoprene diblock copolymer relative to the total amount of the above composition (A2)), 120 parts by mass of Quinton G115 (C5-based / C9-based petroleum resin manufactured by Nippon Zeon Co., Ltd., softening point 115°C) as tackifier resin (b1), 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) as tackifier resin (b2), and 1 part by mass of antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain adhesive D.

[0077] The above pressure-sensitive adhesive D was applied onto release paper using an applicator so that the thickness after drying would be 300 μm, and then dried at 80° C. for 5 minutes to prepare pressure-sensitive adhesive tape D.

[0078] [Example 5] (Preparation of Adhesive E) 100 parts by mass of styrene-isoprene block copolymer composition (A2) (a mixture of styrene-isoprene diblock copolymer and styrene-isoprene triblock copolymer, 24% by mass of styrene-derived structural units represented by the above chemical formula (1), 60% by mass of styrene-isoprene diblock copolymer relative to the total amount of the above composition (A2)), 90 parts by mass of Quinton G115 (C5 / C9 petroleum resin manufactured by Zeon Corporation, softening point 115°C) as tackifier resin (b1), 15 parts by mass of Pencel D-160 (polymerized rosin ester resin manufactured by Arakawa Chemical Industries, Ltd., softening point 150°C to 165°C) as tackifier resin (b2), and 1 part by mass of antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain adhesive E.

[0079] The above-mentioned adhesive E was applied onto a release paper using an applicator so that the thickness after drying would be 300 μm, and then dried at 80° C. for 5 minutes to prepare an adhesive tape E.

[0080] [Example 6] (Preparation of Adhesive F) 100 parts by mass of styrene-isoprene block copolymer composition (A2) (a mixture of styrene-isoprene diblock copolymer and styrene-isoprene triblock copolymer, 24% by mass of styrene-derived structural units represented by the above chemical formula (1), 60% by mass of styrene-isoprene diblock copolymer relative to the total amount of the above composition (A2)), 75 parts by mass of Quinton G115 (C5-based / C9-based petroleum resin manufactured by Nippon Zeon Co., Ltd., softening point 115°C) as tackifier resin (b1), 15 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) as tackifier resin (b2), and 1 part by mass of antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain adhesive F.

[0081] The above pressure-sensitive adhesive F was applied onto release paper with an applicator so that the thickness after drying would be 300 μm, and then dried at 80° C. for 5 minutes to prepare pressure-sensitive adhesive tape F.

[0082] [Comparative Example 1] (Preparation of Adhesive G) 100 parts by mass of styrene-isoprene block copolymer composition (A2) (a mixture of styrene-isoprene diblock copolymer and styrene-isoprene triblock copolymer, 24% by mass of styrene-derived structural units represented by the above chemical formula (1), 60% by mass of styrene-isoprene diblock copolymer relative to the total amount of the above composition (A2)), 70 parts by mass of Quinton G115 (C5 / C9 petroleum resin manufactured by Nippon Zeon Co., Ltd., softening point 115°C) as tackifier resin (b1), 5 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) as tackifier resin (b2), and 1 part by mass of antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain adhesive G.

[0083] The pressure-sensitive adhesive G was applied onto a release paper using an applicator so that the thickness after drying would be 300 μm, and then dried at 80° C. for 5 minutes to prepare a pressure-sensitive adhesive tape F.

[0084] [Comparative Example 2] (Preparation of Adhesive H) 100 parts by mass of a styrene-isoprene block copolymer composition (A2) (a mixture of a styrene-isoprene diblock copolymer and a styrene-isoprene triblock copolymer, 24% by mass of structural units derived from styrene represented by the above chemical formula (1), and the proportion of the styrene-isoprene diblock copolymer to the total amount of the above composition (A2) being 60% by mass), 75 parts by mass of Quinton G115 (a C5 / C9 petroleum resin manufactured by Nippon Zeon Co., Ltd., softening point 115°C) as a tackifier resin (b1), and 1 part by mass of an antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain an adhesive H.

[0085] The above adhesive H was applied onto a release paper using an applicator so that the thickness after drying would be 300 μm, and then dried at 80° C. for 5 minutes to prepare an adhesive tape H.

[0086] [Comparative Example 3] (Preparation of Adhesive I) 100 parts by mass of styrene-isoprene block copolymer composition (A2) (a mixture of styrene-isoprene diblock copolymer and styrene-isoprene triblock copolymer, 24% by mass of styrene-derived structural unit represented by the above chemical formula (1), 60% by mass of styrene-isoprene diblock copolymer relative to the total amount of the above composition (A2)), 40 parts by mass of Quinton G115 (C5-based / C9-based petroleum resin manufactured by Nippon Zeon Co., Ltd., softening point 115°C) as tackifier resin (b1), 40 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) as tackifier resin (b2), and 1 part by mass of antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain adhesive I.

[0087] The above pressure-sensitive adhesive I was applied onto release paper using an applicator so that the thickness after drying would be 300 μm, and then dried at 80° C. for 5 minutes to prepare pressure-sensitive adhesive tape I.

[0088] [Comparative Example 4] (Preparation of Adhesive J) 100 parts by mass of styrene-isoprene block copolymer composition (A2) (a mixture of styrene-isoprene diblock copolymer and styrene-isoprene triblock copolymer, 24% by mass of styrene-derived structural units represented by the above chemical formula (1), 60% by mass of styrene-isoprene diblock copolymer relative to the total amount of the above composition a), 40 parts by mass of Quinton G115 (C5 / C9 petroleum resin manufactured by Zeon Corporation, softening point 115°C) as tackifier resin (b1), 10 parts by mass of Pencel D-160 (polymerized rosin ester resin manufactured by Arakawa Chemical Industries, Ltd., softening point 150°C to 165°C) as tackifier resin (b2), and 1 part by mass of antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain adhesive J.

[0089] The above pressure-sensitive adhesive J was applied onto release paper using an applicator so that the thickness after drying would be 300 μm, and then dried at 80° C. for 5 minutes to prepare pressure-sensitive adhesive tape J.

[0090] [Comparative Example 5] (Preparation of Adhesive K) 100 parts by mass of a styrene-isoprene block copolymer composition (A2) (a mixture of a styrene-isoprene diblock copolymer and a styrene-isoprene triblock copolymer, 24% by mass of the structural unit derived from styrene represented by the above chemical formula (1), and the ratio of the styrene-isoprene diblock copolymer to the total amount of the above composition (A2) is 60% by mass), 75 parts by mass of Pencel D-160 (a polymerized rosin ester resin manufactured by Arakawa Chemical Industries, Ltd., softening point 150°C to 165°C) as a tackifier resin (b2), and 1 part by mass of an antioxidant (tetrakis-[methylene-3-(3'5'-di-t-butyl-4-hydroxyphenyl)propionate]methane) were mixed and dissolved in 100 parts by mass of toluene as a solvent to obtain an adhesive K.

[0091] The above adhesive K was applied onto a release paper using an applicator so that the thickness after drying would be 300 μm, and dried at 80° C. for 5 minutes to prepare an adhesive tape K.

[0092] [Method of measuring T-peel adhesive strength] The above adhesive tape was cut into a size of 20 mm wide x 100 mm long, and a polyethylene (PE) foam (Softlon S#0502, manufactured by Sekisui Chemical Co., Ltd., apparent density 200 kg / m) was applied to both sides of the cut piece. 3 After bonding the two pieces (2.0 mm thick) together, a 2 kg roller was rolled back and forth once on the top surface to press them together, and the result was left in a 60°C environment for 24 hours to ensure sufficient adhesion with the PE foam, thereby producing a test specimen.

[0093] In an environment of 23°C, one end of the adherend of the above test piece was fixed to the lower chuck of the tension device of a Tensilon tensile tester, and the other end of the adherend was fixed to the upper chuck of the tension device of the Tensilon tensile tester, and the upper chuck was pulled at a speed of 50 mm / min to measure the adhesive strength (T-peel adhesive strength).

[0094] [T-peel determination method] The overall judgement of the T-peel measurement was as follows: If the adhesive strength is 20N / 20mm or more and the PE foam breaks and peels off: YES If the adhesive strength is less than 20N / 20mm and the PE foam breaks and peels off: △ If peeling occurs at the interface between the adhesive layer and the PE foam: ×

[0095] [Method of evaluating holding power] One adhesive surface of the above adhesive tape was backed with a 25 μm thick polyethylene terephthalate film, and the tape was cut to a size of 25 mm wide x 100 mm long. This 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 25 mm x 25 mm. A 2 kg roller was rolled back and forth over the top surface 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.

[0096] With the stainless steel plate constituting the test piece fixed, a load of 0.5 kg was applied to the adhesive tape in an environment of 40° 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” in Tables 1 and 2.

[0097] The compositions and evaluation results of the pressure-sensitive adhesive sheets of the Examples and Comparative Examples are shown in the table below.

[0098] [Table 1]

[0099]

Table 2

Claims

1. Contains a styrene-isoprene block copolymer (A) and a tackifier resin (B), The styrene-isoprene block copolymer (A) contains a styrene-isoprene diblock copolymer (a1) and a styrene-isoprene triblock copolymer (a2), The styrene-isoprene block copolymer (A) contains a structural unit represented by the following chemical formula (1) in an amount of 24 to 80 mass %, [0010] The content of the tackifier resin (B) is 75 parts by mass or more based on 100 parts by mass of the styrene-isoprene block copolymer (A), The tackifier resin (B) contains a petroleum resin (b1) and a rosin-based resin (b2), The adhesive tape is characterized in that it has an adhesive layer in which the blending ratio (b1:b2) of the petroleum resin (b1) to the rosin-based resin (b2) is within the range of 2:1 to 10:

1.

2. 2. The pressure-sensitive adhesive tape according to claim 1, wherein the content of said petroleum resin (b1) is 60% by mass or more in 100% by mass of said tackifier resin (B).

3. The pressure-sensitive adhesive tape according to any one of claims 1 to 2, wherein the petroleum resin (b1) is at least one selected from the group consisting of aliphatic petroleum resins, aromatic petroleum resins, and aliphatic / aromatic copolymer petroleum resins.

4. The pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the rosin-based resin (b2) is a polymerized rosin-based resin.

5. The pressure-sensitive adhesive tape according to any one of claims 1 to 4, wherein the proportion of the styrene-isoprene diblock copolymer (a1) relative to the total amount of the styrene-isoprene block copolymer (A) is 10% by mass to 80% by mass.

6. The pressure-sensitive adhesive tape according to any one of claims 1 to 5, which peels off due to material failure of the polyolefin foam when a T-peel adhesive strength to the polyolefin foam is measured by the following measurement method. (Measurement method) An adherend made of a polyolefin foam was attached to each side of the adhesive tape cut to 20 mm width x 100 mm length, and then the upper surface was pressed by rolling a 2 kg roller back and forth once, and left in an environment at 60°C for 24 hours to prepare a test piece. In an environment at 23°C, one end of the adherend of one of the test pieces was fixed to the lower chuck of the tension device of a Tensilon tensile tester, and one end of the adherend of the other test piece was fixed to the upper chuck of the tension device of the Tensilon tensile tester, and the upper chuck was pulled at a speed of 50 mm / min to measure the T-peel adhesive strength.

7. The pressure-sensitive adhesive tape according to any one of claims 1 to 6, which has a T-peel adhesive strength to a polyolefin foam of 15 N / 20 mm or more, as measured by the following measuring method. (Measurement method) An adherend made of a polyolefin foam was attached to each side of the adhesive tape cut to 20 mm width x 100 mm length, and then the upper surface was pressed by rolling a 2 kg roller back and forth once, and left in an environment at 60°C for 24 hours to prepare a test piece. In an environment at 23°C, one end of the adherend of one of the test pieces was fixed to the lower chuck of the tension device of a Tensilon tensile tester, and one end of the adherend of the other test piece was fixed to the upper chuck of the tension device of the Tensilon tensile tester, and the upper chuck was pulled at a speed of 50 mm / min to measure the T-peel adhesive strength.

8. Contains a styrene-isoprene block copolymer (A) and a tackifier resin (B), The styrene-isoprene block copolymer (A) contains a styrene-isoprene diblock copolymer (a1) and a styrene-isoprene triblock copolymer (a2), The styrene-isoprene block copolymer (A) contains a structural unit represented by the following chemical formula (1) in an amount of 24 to 80 mass %, [0010] The content of the tackifier resin (B) is 75 parts by mass or more based on 100 parts by mass of the styrene-isoprene block copolymer (A), The tackifier resin (B) contains a petroleum resin (b1) and a rosin-based resin (b2), The pressure-sensitive adhesive has a compounding ratio (b1:b2) of the petroleum resin (b1) to the rosin-based resin (b2) within a range of 2:1 to 10:1.

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