adhesive tape

Abstract

To provide an adhesive tape which exhibits an improved service life even in such a form that the adhesive tape is stuck onto a rough surface and strong stress is frequently applied on the rough surface.SOLUTION: An adhesive tape includes a base material having a first surface and a second surface, and an adhesive layer arranged on the first surface of the base material. The base material includes at least an A layer that is a layer composed of a resin composition (a) and constitutes the first surface, and a B layer that is a layer composed of a resin composition (b) and is arranged on a side closer to the second surface than the A layer. The resin composition (a) contains 50 wt.% or more of a filler. The adhesive tape has tensile strength FT of 35 N / 15 mm or more and 145 N / 15 mm or less.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Generally, adhesives (also referred to as pressure-sensitive adhesives; the same applies hereinafter) are in a soft solid (viscoelastic) state at temperatures around room temperature and have the property of easily adhering to an adherend when pressure is applied. Utilizing these properties, adhesives are widely used in a variety of fields, typically in the form of adhesive tapes having an adhesive layer on a substrate, for purposes such as joining, fixing, surface protection, masking, and marking. Generally, adhesive marking tapes are used, for example, as line tapes for marking divisions, markers, information, etc. on the floors of factories, gymnasiums, etc., and as tapes for forming tiger patterns (yellow and black stripes) to draw attention at construction sites, etc. Patent Document 1 is an example of a technical document related to adhesive marking tapes. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-279202 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional marking adhesive tapes are prone to peeling or damage (tears, chips, etc.) when used in a manner that involves being attached to a rough surface and repeatedly subjecting the adhesive tape to strong stress from its backside (specifically, when used in a harsh manner, such as when the tape is attached to an outdoor paved surface and vehicles frequently pass over it). If the period during which the above-mentioned adhesive tape can properly perform its functions (use life) could be improved, it would be beneficial from the perspective of maintaining a good appearance for a longer period of time where the adhesive tape is attached, and reducing the frequency of replacing the tape with new adhesive tape, thereby reducing the workload and saving resources.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an adhesive tape that exhibits an improved service life even when applied to a rough surface and subjected to frequent high stresses from above. [Means for solving the problem]

[0006] The pressure-sensitive adhesive tape provided by this specification comprises a substrate having a first side and a second side, and a pressure-sensitive adhesive layer disposed on the first side of the substrate. The substrate comprises at least a layer A composed of a resin composition (a) constituting the first side, and a layer B composed of a resin composition (b) disposed closer to the second side than the layer A. Here, the resin composition (a) contains 50% by weight or more of a filler. The pressure-sensitive adhesive tape has a tensile strength F measured as the maximum tensile load [N / 15 mm] when a 15 mm wide test piece is stretched to break using a tensile tester under conditions of 23°C and 50% RH, with a chuck distance of 15 mm and a pulling rate of 300 mm / min. T However, it is between 35N / 15mm and 145N / 15mm.

[0007] In the adhesive tape having the above-mentioned configuration, the resin composition (a) constituting the layer A (i.e., the layer disposed on the adhesive layer side) of the substrate contains 50% by weight or more of a filler, which is advantageous from the viewpoint of enhancing plastic deformability to a shape that conforms to irregularities that may exist on the surface of the adherend (for example, irregularities on a rough surface such as a paved surface). In addition, the tensile strength F of the adhesive tape T Since the tensile strength F is limited to 145N / 15mm or less, the effect of making the entire adhesive tape conform well to the irregularities of the adherend surface can be adequately exhibited by utilizing the plastic deformability of the A layer. An adhesive tape that conforms well to the irregularities of the adherend surface (adhesion) is preferred because it is easy to prevent lifting or peeling from the adherend. The adhesive tape has a tensile strength F of 35N / 15mm or more. TTherefore, even in a case where the adhesive tape is attached to a rough surface and is frequently subjected to strong stress from above, the adhesive tape having the above-mentioned configuration can be prevented from lifting or peeling off from the rough surface or from being damaged, thereby improving the service life of the adhesive tape.

[0008] In some embodiments of the pressure-sensitive adhesive tape disclosed herein, the pressure-sensitive adhesive tape preferably has a sag of 55 mm or more as measured by the following method: A pressure-sensitive adhesive tape having a sag of 55 mm or more can more effectively utilize the plastic deformability of Layer A to allow the entire pressure-sensitive adhesive tape to conform well to the irregularities of the adherend surface. [Sagging measurement] In an environment of 23°C and 50% RH, a test piece 50 mm wide and 300 mm long is held cantilevered on a horizontal holding stand with the adhesive layer side facing downwards so that a 100 mm length from one end of the test piece extends outward from the holding stand, and after leaving it to stand for 10 minutes, the difference in height between the top surface of the holding stand and one end of the test piece is measured.

[0009] The resin composition (a) constituting the layer A of the substrate preferably contains an elastomer as a base resin. The pressure-sensitive adhesive tape disclosed herein can be suitably implemented in an embodiment including a substrate having a layer A constituted by a resin composition (a) containing an elastomer as a base resin and 50 wt % or more of a filler.

[0010] In some preferred embodiments, the resin composition (b) constituting Layer B of the substrate may be a composition containing a polyolefin resin as a base resin. For example, in a pressure-sensitive adhesive tape in which the second surface of the substrate is constituted by Layer B and the second surface also serves as the back surface of the pressure-sensitive adhesive tape, it may be advantageous from the viewpoint of the antifouling properties of the back surface of the pressure-sensitive adhesive tape that the resin composition (b) is a composition containing a polyolefin resin as a base resin.

[0011] In some embodiments, the substrate has a thickness T B [μm] vs. the thickness T of the above A layer A [μm] ratio (T A / T B ) is preferably 0.5 or more and 10 or less. A / T B ) in the above range, it is easy to realize an adhesive tape that satisfies both the conformability to rough surfaces (e.g., paved surfaces) and durability to stress from the back surface of the adhesive tape (e.g., stress associated with the passage of vehicles).

[0012] In some preferred embodiments, the total thickness of the adhesive tape is 2000 μm or less. Not having an excessively large total thickness of the adhesive tape is advantageous from the viewpoint of reducing the step that occurs on the adherend (e.g., paved surface) when the adhesive tape is applied.

[0013] In some embodiments of the adhesive tape disclosed herein, the thickness T P [μm] and the thickness T of the above A layer A [μm] and the total thickness (T P +T A The total thickness of the adhesive layer and layer A (T P +T A ) is 150 μm or more, is preferred because even if the adherend is a rough surface such as a paved surface, the adhesive tape can be easily adapted to the rough surface by utilizing the easy deformability of the adhesive layer and the plastic deformability of Layer A.

[0014] In some embodiments of the pressure-sensitive adhesive tape disclosed herein, an acrylic pressure-sensitive adhesive layer can be preferably used as the pressure-sensitive adhesive layer of the pressure-sensitive adhesive tape. For pressure-sensitive adhesive tapes intended for outdoor use (for example, use in a form in which the tape is attached to an outdoor pavement), it is particularly preferred that the pressure-sensitive adhesive layer be an acrylic pressure-sensitive adhesive layer from the viewpoints of weather resistance, heat resistance, etc.

[0015] The adhesive tape disclosed herein can achieve a good balance between conformability to rough surfaces and durability against backside stress, and is therefore suitable as an adhesive tape to be attached to outdoor pavement surfaces. In particular, the application effects of the technology disclosed herein can be preferably exhibited in applications where the tape is attached to outdoor pavement surfaces over which vehicles frequently pass.

[0016] The adhesive tape disclosed herein can be preferably used, for example, as a marking adhesive tape. Thus, according to this specification, there is provided an adhesive tape for marking comprising any of the adhesive tapes disclosed herein.

[0017] Appropriate combinations of the elements described in this specification may also be included within the scope of the invention for which patent protection is sought by this patent application. [Brief explanation of the drawings]

[0018] [Figure 1] 1 is a cross-sectional view schematically illustrating a pressure-sensitive adhesive tape according to an embodiment. [Figure 2] FIG. 2 is an explanatory diagram schematically showing a method for measuring sagging. DETAILED DESCRIPTION OF THE INVENTION

[0019] Preferred embodiments of the present invention will be described below. Matters necessary for carrying out the present invention other than those specifically mentioned in this specification can be understood by those skilled in the art based on the teachings on carrying out the invention described in this specification and the common general technical knowledge at the time of filing. The present invention can be carried out based on the contents disclosed in this specification and the common general technical knowledge in the relevant field. In the following drawings, components and parts having the same function may be denoted by the same reference numerals, and redundant explanations may be omitted or simplified. The embodiments shown in the drawings are schematic in order to clearly explain the present invention, and do not necessarily accurately represent the size or scale of the actual product.

[0020] <Adhesive tape structure example> The adhesive tape disclosed herein includes a substrate and an adhesive layer disposed on a first surface of the substrate. The concept of "adhesive tape" in this specification may include what is called an "adhesive sheet." The adhesive tape disclosed herein typically has a shape in which the longitudinal dimension is larger than the width dimension, and is preferably configured in a strip shape in which the longitudinal dimension is larger than the width dimension. In an adhesive tape having a substrate configured to include a resin film, the machine direction (MD) of the resin film generally corresponds to the longitudinal direction of the adhesive tape.

[0021] FIG. 1 shows a schematic diagram of an example of the configuration of an adhesive tape according to one embodiment. This adhesive tape 1 includes a sheet-like substrate 10 having a first side 10A and a second side 10B, and an adhesive layer 20 disposed on the first side 10A. The substrate 10 has a laminated structure (a two-layer structure or a three-layer structure; in this embodiment, a two-layer structure) including at least Layer A and Layer B, each having a different composition. Layer A constitutes the first side 10A of the substrate 10 and is composed of a resin composition (a) containing 50% or more by weight of a filler. Layer B is disposed closer to the second side 10B of the substrate 10 than Layer A and is composed of a resin composition (b) having a different composition from the resin composition (a). In the example shown in FIG. 1, the substrate 10 is a two-layer resin film in which Layer A 12, which constitutes the first side 10A, and Layer B 14, which constitutes the second side 10B, are laminated in direct contact with each other. The second surface 10B of the substrate 10 also serves as the back surface of the pressure-sensitive adhesive tape 1 (the surface opposite to the adhesive surface 20A). The substrate 10 may further include an auxiliary layer (not shown) as an optional component. The A layer 12 may be a resin layer containing an elastomer as a base resin and 50% by weight or more of a filler. The B layer 14 may be a resin layer containing a polyolefin resin and / or an ethylene-vinyl acetate copolymer as a base resin. The B layer 14 may or may not contain a filler.

[0022] Before use (i.e., before application to an adherend), the adhesive tape 1 may be in the form of an adhesive tape roll, for example, wound longitudinally so that the adhesive layer 20 abuts against the second surface 10B of the substrate (which may also serve as the back surface of the adhesive tape), thereby protecting its surface (adhesive surface) 20A. Alternatively, the adhesive tape before use may be in a form in which the surface of the adhesive layer is protected by a release liner that is separate from the adhesive tape and at least the side facing the adhesive layer serves as a release surface. Any known or commonly used release liner can be used without any particular limitation. For example, a release liner having a release-treated layer on the surface of a substrate such as a plastic film or paper, or a release liner made of a low-adhesion material such as a fluorine-based polymer (e.g., polytetrafluoroethylene) or a polyolefin-based resin (e.g., polyethylene or polypropylene), can be used.

[0023] <Base material> The substrate of the adhesive tape disclosed herein has a first side, which is the surface on which the adhesive layer is disposed, and a second side, which is the surface opposite to the first side. The substrate includes at least Layer A, which constitutes the first side, and Layer B, which is disposed closer to the second side than Layer A. Hereinafter, Layer A may be referred to as the "inner layer" and Layer B may be referred to as the "outer layer" based on their relative positions when attached to an adherend.

[0024] (Layer A (inner layer)) Layer A of the substrate is a layer composed of a resin composition (a) containing 50% by weight or more of a filler. The filler may be an organic filler, an inorganic filler, or an organic-inorganic composite filler. The filler may be subjected to a known or conventional surface treatment. From the viewpoints of cost and availability, inorganic fillers are preferably used.

[0025] Examples of inorganic fillers include calcium carbonate, magnesium carbonate, aluminum hydroxide, magnesium hydroxide, zirconium hydroxide, calcium hydroxide, potassium hydroxide, barium hydroxide, zirconium oxide, magnesium oxide, zinc oxide, titanium oxide, molybdenum oxide, hydrotalcite, smectite, zeolite, zinc borate, anhydrous zinc borate, zinc metaborate, barium metaborate, antimony oxide, antimony trioxide, antimony pentoxide, red phosphorus, talc, alumina, silica, boehmite, bentonite, sodium silicate, calcium silicate, calcium sulfate, carbon black, etc. Among these, calcium carbonate, magnesium carbonate, hydrotalcite, talc, alumina, silica, calcium silicate, and calcium sulfate are preferred, and calcium carbonate is more preferred.

[0026] The average particle size of the filler is not particularly limited and may be, for example, about 0.1 μm to 100 μm. In some embodiments, from the viewpoints of handleability, dispersibility, and the like, the average particle size of the filler is preferably 0.5 μm or more, and may be 1 μm or more, or may be 3 μm or more. Furthermore, in some embodiments, from the viewpoint of easily imparting appropriate plastic deformability to layer A, the average particle size of the filler is suitably 70 μm or less, and is preferably 50 μm, and may be 30 μm or less, 20 μm or less, 15 μm or less, or 10 μm or less (e.g., 7 μm or less). Unless otherwise specified, the term "average particle size" in this specification refers to the particle size at 50% of the integrated value in the particle size distribution measured using a particle size distribution measuring device based on the laser diffraction scattering method (50% volume average particle size).

[0027] The filler content in resin composition (a) (which typically corresponds to the filler content in layer A) is not particularly limited and can be appropriately set within a range of 50% by weight or more and less than 100% by weight. In some embodiments, the filler content in layer A may be, for example, 95% by weight, 90% by weight or less, less than 90% by weight, 88% by weight or less, 85% by weight or less, 80% by weight or less, or 75% by weight or less, from the viewpoint of ease of molding layer A and ease of manufacturing the substrate. Furthermore, the filler content in layer A may be, for example, more than 50% by weight, 52% by weight or more, 55% by weight or more, 60% by weight or more, or 65% by weight or more, from the viewpoint of easily imparting appropriate brittleness (which may also be understood as low plastic deformability or toughness) to layer A.

[0028] The base resin of the resin composition (a) can be appropriately selected from various resins that can be used for the substrate of a pressure-sensitive adhesive tape. In some preferred embodiments, an elastomer is used as the base resin. Non-limiting examples of the elastomer include ethylene-vinyl acetate copolymer (EVA), ethylene-propylene rubber, thermoplastic polyolefin elastomer (TPO), thermoplastic polyurethane elastomer (TPU), thermoplastic polyester elastomer (TPEE), polyvinyl chloride, (meth)acrylate-butadiene-styrene copolymer (e.g., methyl methacrylate-butadiene-styrene copolymer), acrylonitrile-butadiene-styrene copolymer, acrylonitrile-butadiene copolymer (NBR), styrene-butadiene copolymer, styrene-butadiene-styrene copolymer, and other synthetic rubbers (isoprene rubber, butadiene rubber, etc.). These can be used alone or in appropriate combinations of two or more. Among these, EVA is a preferred base resin. For example, EVA having a vinyl acetate content of about 5 to 50% by weight (preferably about 10 to 47% by weight, e.g., about 15 to 45% by weight) can be used. Commercially available EVA products include Ultrathene series (trade name) manufactured by Tosoh and Evaflex series (trade name) manufactured by Mitsui Dow Polychemicals. The base resin of Layer A refers to the resin component that constitutes Layer A. The same applies to the base resin of Layer B, which will be described later.

[0029] A layer thickness (T A ) is suitably approximately 50 μm or more, advantageously 100 μm or more, preferably 150 μm or more, more preferably 200 μm or more, and may be 300 μm or more, 400 μm or more, 500 μm or more, 600 μm or more, or even 700 μm or more, from the viewpoint of adhesion to irregularities that may exist on the surface of the adherend (for example, irregularities on a rough surface such as a paved surface). Furthermore, from the viewpoint of reducing the height of steps that occur on the adherend when the pressure-sensitive adhesive tape is applied, the thickness of layer A is suitably approximately 1800 μm or less, preferably 1600 μm or less, may be 1400 μm or less, 1200 μm or less, 1000 μm or less, or may be 900 μm or less.

[0030] (B layer (outer layer)) Layer B of the substrate is a layer composed of resin composition (b). The base resin of resin composition (b) can be appropriately selected from various resins that can be used as resin materials for forming substrates of pressure-sensitive adhesive tapes. Suitable examples of base resins that can form pressure-sensitive adhesive tapes that combine durability with conformability to rough surfaces such as road surfaces include polyolefin resins and ethylene-vinyl acetate copolymers (EVA). Other examples of materials that can be used as the base resin of resin composition (b) include the materials exemplified as base resins that can be used in resin composition (a). The base resin of resin composition (b) can be used alone or in appropriate combination of two or more. Among these, polyolefin resins are preferred. Using a polyolefin resin as the base resin of resin composition (b) can be advantageous from the perspective of the stain resistance of the pressure-sensitive adhesive tape. This is particularly significant, for example, in a configuration in which layer B forms the other surface of the substrate, and the other surface also serves as the back surface of the pressure-sensitive adhesive tape.

[0031] The polyolefin resin can be a single polyolefin or a combination of two or more polyolefins. Examples of the polyolefin include homopolymers of α-olefins, copolymers of two or more α-olefins, and copolymers of one or more α-olefins with other vinyl monomers. Specific examples include polyethylene (PE), polypropylene (PP), ethylene-propylene copolymers such as poly-1-butene, poly-4-methyl-1-pentene, and ethylene-propylene rubber (EPR), ethylene-propylene-butene copolymers, ethylene-butene copolymers, ethylene-vinyl alcohol copolymers, and ethylene-ethyl acrylate copolymers. Examples of PE include linear low-density polyethylene (LLDPE), low-density polyethylene (LDPE), medium-density polyethylene, and high-density polyethylene. Suitable examples of PE include LLDPE and LDPE. Among these, LLDPE is preferred.

[0032] In some embodiments, a polyolefin-based resin containing a combination of PE and an α-olefin copolymer can be preferably used as the base resin of resin composition (b). Specific examples include a polyolefin-based resin containing LLDPE and an α-olefin copolymer, a polyolefin-based resin containing LDPE and an α-olefin copolymer, and a polyolefin-based resin containing LLDPE, LDPE, and an α-olefin copolymer. The weight ratio of PE to the α-olefin copolymer may be, for example, 5 / 95 to 95 / 5, preferably 10 / 90 to 95 / 5, more preferably 25 / 75 to 90 / 10, 30 / 70 to 90 / 10, 30 / 70 to 85 / 20, 40 / 60 to 80 / 20, or 40 / 60 to 60 / 40.

[0033] The resin composition (b) may contain a filler in addition to the base resin. Examples of the filler include the same materials as those described above as fillers that can be used in the resin composition (a). The average particle size of the filler used in the resin composition (b) can be appropriately selected from the same range as the average particle size of the filler used in the resin composition (a).

[0034] By appropriately setting the filler content in resin composition (b) (which usually corresponds to the filler content in layer B), it is possible to adjust the tensile strength of layer B, the tensile strength of the pressure-sensitive adhesive tape, and the sagging of the pressure-sensitive adhesive tape, as described below. The filler content in layer B can be appropriately set within a range greater than 0% by weight, and may be, for example, 10% by weight or more, 15% by weight or more, 20% by weight or more, or more than 20% by weight, 25% by weight or more, 30% by weight or more, 40% by weight or more, 50% by weight or more, 60% by weight or more, or 65% by weight or more. Furthermore, from the viewpoint of the strength and durability of layer B, the filler content in layer B is suitably 95% by weight or less, advantageously 90% by weight or less, preferably less than 90% by weight, more preferably 88% by weight or less, or may be 85% by weight or less, less than 85% by weight, 80% by weight or less, or 75% by weight or less. For example, in embodiments in which the base resin of resin composition (b) is a polyolefin resin, EVA, or a mixture thereof, the filler content described above can be preferably employed. Also, in some embodiments in which EVA is used as the base resin of resin composition (b), the filler content of layer B is advantageously, for example, 60% by weight or less, preferably 50% by weight or less or less than 50% by weight, or may be 45% by weight or less, 40% by weight or less, or 35% by weight or less.

[0035] B layer thickness (T B) is suitably 20 μm or more, advantageously 50 μm or more, preferably 75 μm or more, more preferably 100 μm or more, and may be 150 μm or more, 200 μm or more, 300 μm or more, 350 μm or more, or 380 μm or more, from the viewpoint of easily setting one or more of the tensile strength of Layer B, the tensile strength of the adhesive tape, and the sagging of the adhesive tape within an appropriate range. Furthermore, from the viewpoint of reducing the height of steps that occur on the adherend when the adhesive tape is applied, the thickness of Layer B is suitably approximately 1600 μm or less, preferably 1400 μm or less, or may be 1200 μm or less, 1000 μm or less, 800 μm or less, 60 μm or less, or 500 μm or less.

[0036] The thickness of the entire substrate including Layer A and Layer B is not particularly limited and can be selected depending on the purpose and mode of use of the pressure-sensitive adhesive tape. The thickness of the substrate can be selected, for example, from the range of about 70 μm to about 1900 μm. From the viewpoint of making it easier to extend the service life of the pressure-sensitive adhesive tape, in some embodiments, the total thickness of the substrate is suitably 100 μm or more, preferably 200 μm or more, more preferably 250 μm or more, and may be, for example, 400 μm or more, 600 μm or more, 800 μm or more, 1000 μm or more, or 1100 μm or more. Furthermore, from the viewpoint of reducing the height of steps that occur on the adherend when the pressure-sensitive adhesive tape is applied, in some embodiments, the thickness of the substrate may be, for example, 1980 μm or less, suitably 1950 μm or less, preferably 1900 μm or less, or may be 1800 μm or less, 1600 μm or less, 1500 μm or less, 1400 μm or less, or may be 1450 μm or less.

[0037] In some embodiments, the thickness T of the B layer B [μm] vs. A layer thickness T A Thickness ratio (T A / T B) may be, for example, about 0.2 to 50, and preferably about 0.5 to 10. From the viewpoint of easily exhibiting good conformability to the irregularities on the adherend surface, in some embodiments, the above ratio (T A / T B ) is suitably 0.7 or more, advantageously 1.0 or more or more than 1.0, preferably 1.2 or more, more preferably 1.5 or more, may be 1.6 or more, or may be 1.8 or more. In addition, from the viewpoint of easily obtaining good durability while avoiding an excessive increase in the total thickness of the pressure-sensitive adhesive tape, the above ratio (T A / T B ) is suitably 8.0 or less, advantageously 6.0 or less, preferably 4.0 or less, may be 3.0 or less, or may be 2.5 or less.

[0038] From the viewpoint of durability, the substrate of the adhesive tape disclosed herein can be preferably implemented in an embodiment in which at least the A layer and the B layer are both non-porous resin layers. Here, a non-porous resin layer typically means a resin layer that is substantially bubble-free (for example, a void-free resin layer in which the proportion of bubbles in the apparent volume of the substrate is less than 3% by volume, preferably less than 1% by volume). It is preferable that the entire substrate is non-porous.

[0039] The resin material constituting each layer of the substrate may contain known additives such as light stabilizers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), slip agents, antiblocking agents, etc., as needed, within the range that does not significantly impair the effects of the present invention. The amount of additives to be added is not particularly limited, and can be appropriately set so as to achieve the desired effect when used.

[0040] The method for producing the substrate is not particularly limited, and can be produced by known methods such as co-extrusion molding of the resin materials constituting each layer, thermal lamination or lamination with an adhesive of resin films individually formed from each resin material, extrusion lamination of a resin material constituting a layer onto a resin film constituting another layer, combinations or repetitions of these, etc. The resin film can be produced by conventionally known general resin film molding methods such as extrusion molding, inflation molding, T-die casting molding, calendar roll molding, calendar processing, etc.

[0041] The substrate of the pressure-sensitive adhesive tape disclosed herein may be configured to include at least Layer A and Layer B, and may be a substrate with a two-layer structure consisting of Layer A and Layer B, or a substrate with a structure further including one or more layers (hereinafter also referred to as optional layers) different from Layer A and Layer B. In some embodiments using a substrate with a structure including optional layers, from the viewpoint of easily and favorably exhibiting the effects of including Layer A and Layer B, the total thickness of Layer A and Layer B is preferably 80% or more, more preferably 90% or more or 95% or more (e.g., 98% or more) of the total thickness of the substrate.

[0042] The optional layer may be, for example, an optical property adjusting layer (e.g., a colored layer or an antireflection layer), a printed layer or a laminate layer for imparting a desired appearance to the substrate, an antistatic layer, a hard coat layer provided for the purpose of improving the durability of the substrate (scratch resistance, abrasion resistance, stain resistance, etc.), a release layer for imparting releasability to the back surface of the pressure-sensitive adhesive tape (the surface opposite to the adhesive surface), an undercoat layer (primer layer) provided for the purpose of improving the anchoring property of the pressure-sensitive adhesive layer to the substrate or improving the adhesion between the substrate and the hard coat layer, etc. As the hard coating agent for forming the hard coating layer, known materials such as acrylic, urethane, urethane acrylate, and silicone materials can be appropriately used. The thickness of the hard coating layer is not particularly limited and can be appropriately set depending on the purpose. In some embodiments, the thickness of the hard coating layer may be, for example, about 0.1 μm to 100 μm, or about 1 μm to 50 μm. As the release treatment agent for forming the release layer, known materials such as silicone-based, long-chain alkyl-based, fluorine-based, molybdenum sulfide, etc. can be appropriately used. The thickness of the release layer is not particularly limited and can be appropriately set depending on the purpose. In some embodiments, the thickness of the release layer may be, for example, about 0.01 μm to 5 μm, or about 0.05 μm to 3 μm. The composition of the primer used to form the undercoat layer is not particularly limited and can be appropriately selected from known primers. The thickness of the undercoat layer is not particularly limited and can be appropriately set depending on the purpose. In some embodiments, the thickness of the undercoat layer may be, for example, about 0.01 μm to 1 μm, or about 0.1 μm to 1 μm.

[0043] The optional layer may be disposed on the surface of Layer A (between Layer A and the pressure-sensitive adhesive layer), may constitute the second surface of the substrate (the surface on the back side of the pressure-sensitive adhesive tape), or may be disposed between Layer A and Layer B. Furthermore, the optional layer may be provided over the entire area of ​​the substrate, or may be provided partially.

[0044] The first surface of the substrate may be subjected to a conventionally known surface treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, or alkali treatment, as necessary. Such a surface treatment may be a treatment for improving the anchoring ability of the pressure-sensitive adhesive layer to the substrate. The above surface treatments may be applied alone or in combination.

[0045] <Adhesive layer> The adhesive layer of the adhesive tape disclosed herein can be composed of one or more types of adhesives appropriately selected from various types of adhesives. Examples of such adhesives include, but are not limited to, acrylic adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, rubber adhesives, polyether adhesives, silicone adhesives, and fluorine-based adhesives. Here, an acrylic adhesive refers to an adhesive having an acrylic polymer as the base polymer. Similarly, a polyester adhesive refers to an adhesive having a polyester as the base polymer. The same applies to rubber adhesives and other adhesives. Furthermore, the base polymer of an adhesive refers to the main component of the rubber-like polymer (a polymer that exhibits rubber elasticity at temperatures around room temperature) contained in the adhesive, and typically refers to a component that accounts for more than 50 wt % (e.g., 70 wt % or more, or even 90 wt % or more) of the polymer components. The adhesive tape disclosed herein can be preferably implemented, for example, in an embodiment having an adhesive layer (acrylic adhesive layer) formed using an acrylic adhesive.

[0046] In this specification, the term "acrylic polymer" refers to a polymer containing monomer units derived from (meth)acrylic monomers in the polymer structure, typically a polymer containing more than 50% by weight of monomer units derived from (meth)acrylic monomers. Furthermore, a (meth)acrylic monomer refers to a monomer having at least one (meth)acryloyl group in one molecule. Here, the term "(meth)acryloyl group" refers to both acryloyl and methacryloyl groups. Therefore, the term "(meth)acrylic monomer" as used herein encompasses both monomers having an acryloyl group (acrylic monomers) and monomers having a methacryloyl group (methacrylic monomers). Similarly, in this specification, the term "(meth)acrylic acid" refers to both acrylic acid and methacrylic acid, and the term "(meth)acrylate" refers to both acrylate and methacrylate.

[0047] (acrylic polymer) The acrylic polymer serving as the base polymer of the acrylic pressure-sensitive adhesive is preferably a polymer of a monomer raw material that contains, for example, an alkyl(meth)acrylate as a main monomer and may further contain a secondary monomer copolymerizable with the main monomer, where the main monomer is a component that accounts for more than 50% by weight of all the monomer components in the monomer raw material.

[0048] As the alkyl(meth)acrylate, for example, a compound represented by the following formula (1) can be suitably used. CH2=C(R 1 )COOR 2 (1) Here, R in the above formula (1) 1 is a hydrogen atom or a methyl group. 2 is a chain alkyl group having 1 to 20 carbon atoms (hereinafter, this range of carbon atoms is referred to as "C 1-20 From the viewpoint of the storage modulus of the adhesive, R 2 C 1-14 (For example, C 2-10 , typically C 4-9 ), alkyl (meth)acrylates in which R 1 is a hydrogen atom and R 2 C 4-9 Alkyl acrylate, which is a chain alkyl group, is more preferred.

[0049] R 2 C 1-20Examples of alkyl(meth)acrylates, which are chain alkyl groups, include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, isopropyl(meth)acrylate, n-butyl(meth)acrylate, isobutyl(meth)acrylate, s-butyl(meth)acrylate, pentyl(meth)acrylate, isopentyl(meth)acrylate, hexyl(meth)acrylate, heptyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, octyl(meth)acrylate, and isooctyl(meth)acrylate. Examples of alkyl (meth)acrylates include butyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. These alkyl (meth)acrylates can be used alone or in combination of two or more. Particularly preferred alkyl (meth)acrylates include n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA). BA and 2EHA can be used alone or in combination.

[0050] The blending ratio of the main monomer in the total monomer components is preferably about 70% by weight or more (for example, about 85% by weight or more, typically about 90% by weight or more), and usually about 99.5% by weight or less (for example, about 99% by weight or less). 4-9 When alkyl acrylate is used, C among the alkyl (meth)acrylates contained in the monomer component 4-9The proportion of alkyl acrylate is preferably about 70% by weight or more, more preferably about 90% by weight or more, and even more preferably about 95% by weight or more (typically about 99% by weight or more and about 100% by weight or less). In a preferred embodiment, the monomer component includes at least one of BA and 2EHA. The technology disclosed herein can be preferably implemented, for example, in an embodiment in which the total amount of BA and 2EHA accounts for about 50% by weight or more (typically about 70% by weight or more, e.g., about 90% by weight or more) of the total monomer components.

[0051] A secondary monomer copolymerizable with the alkyl (meth)acrylate main monomer can be useful for introducing crosslinking points into the acrylic polymer or for increasing the cohesive strength of the acrylic polymer. Examples of the secondary monomer include one or more functional group-containing monomers, such as carboxyl group-containing monomers, hydroxyl group-containing monomers, acid anhydride group-containing monomers, amide group-containing monomers, amino group-containing monomers, keto group-containing monomers, monomers having a nitrogen atom-containing ring, alkoxysilyl group-containing monomers, imide group-containing monomers, and epoxy group-containing monomers. From the viewpoint of improving cohesive strength, acrylic polymers in which a carboxyl group-containing monomer and / or a hydroxyl group-containing monomer is copolymerized as the secondary monomer are preferred. Suitable examples of the carboxyl group-containing monomer include acrylic acid and methacrylic acid. Suitable examples of the hydroxyl group-containing monomer include hydroxyalkyl (meth)acrylates, such as 2-hydroxyethyl acrylate and 4-hydroxybutyl acrylate.

[0052] The amount of the secondary monomer is not particularly limited and may be appropriately selected so as to achieve the desired cohesive strength. From the viewpoint of achieving a good balance between adhesive strength and cohesive strength, the amount of the secondary monomer is usually about 0.5% by weight or more, preferably about 1% by weight or more, of the total monomer components of the acrylic polymer. Furthermore, the amount of the secondary monomer is usually about 30% by weight or less, preferably about 15% by weight or less (e.g., about 10% by weight or less), of the total monomer components.

[0053] The acrylic polymer may be copolymerized with a monomer (other monomer) other than those mentioned above. The other monomer can be used, for example, to adjust the glass transition temperature of the acrylic polymer, adjust the adhesive performance (e.g., releasability), etc. Examples of monomers that can improve the cohesive strength of the adhesive include sulfonic acid group-containing monomers, phosphate group-containing monomers, cyano group-containing monomers, vinyl esters (vinyl acetate, vinyl propionate, vinyl laurate, etc.), aromatic vinyl compounds, etc. The other monomers may be used alone or in combination of two or more. The content of the other monomers is preferably about 30% by weight or less (e.g., about 10% by weight or less) of the total monomer components, and can be, for example, about 0.01% by weight or more (typically about 0.1% by weight or more).

[0054] The method for obtaining the acrylic polymer is not particularly limited, and the polymer can be obtained by applying various polymerization methods commonly used as a synthesis method for acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, etc. The acrylic polymer may be a random copolymer, a block copolymer, a graft copolymer, etc. From the viewpoint of productivity, etc., a random copolymer is usually preferred.

[0055] (Crosslinking agent) A crosslinking agent may be used in the pressure-sensitive adhesive layer (e.g., an acrylic pressure-sensitive adhesive layer) as needed. Examples of the crosslinking agent include, but are not limited to, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, silicone-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, silane-based crosslinking agents, alkyl-etherified melamine-based crosslinking agents, and metal chelate-based crosslinking agents. The crosslinking agents may be used alone or in combination of two or more. In some embodiments, an epoxy-based crosslinking agent may be preferably used as the crosslinking agent. An epoxy-based crosslinking agent may also be used in combination with another crosslinking agent.

[0056] The amount of a crosslinking agent used is not particularly limited, and may be an amount greater than 0 parts by weight relative to 100 parts by weight of the solid content of the adhesive (e.g., an acrylic adhesive) to which the crosslinking agent is added, and may be an amount that adequately exhibits the effects of use. For example, the amount of crosslinking agent used may be appropriately set within the range of approximately 0.005 to 15 parts by weight (preferably 1 to 5 parts by weight) relative to 100 parts by weight of the adhesive, based on the solid content (non-volatile content). In some embodiments, the amount of crosslinking agent used may be, for example, 0.005 parts by weight or more, preferably 0.010 parts by weight or more (e.g., 0.015 parts by weight or more), based on 100 parts by weight of the adhesive, based on the solid content (non-volatile content). It may also be 0.1 parts by weight or more, more than 0.5 parts by weight, 0.7 parts by weight or more, more than 1.0 parts by weight, more than 1.2 parts by weight, more than 1.5 parts by weight, or more than 2.0 parts by weight. In some embodiments, the amount of crosslinking agent used is suitably, for example, 15 parts by weight or less, based on the solid content (non-volatile content) of the adhesive, relative to 100 parts by weight of the adhesive, and may be 10 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, 1 part by weight or less, 0.5 parts by weight or less, or 0.1 parts by weight or less (e.g., 0.05 parts by weight or less). Using an amount of crosslinking agent that is not too large can be advantageous, for example, from the viewpoint of the adhesiveness of the adhesive tape to the adherend (which, in the case of an adherend having an uneven surface, can also be understood as the ability to penetrate into the unevenness).

[0057] (tackifier) The pressure-sensitive adhesive layer may contain a tackifier, if necessary. The use of a tackifier can improve adhesion to an adherend. Examples of preferred tackifiers include tackifier resins such as rosin resins, terpene resins, petroleum resins, phenolic resins, alkylphenol resins, xylene resins, coumarone-indene resins, alkyd resins, epoxy resins, and hydrogenated versions thereof. One tackifier can be used alone, or two or more tackifiers can be used in appropriate combination. When a tackifier is used, its amount can be determined so as to achieve the desired effect, and is not particularly limited. The amount of tackifier used can be, for example, 5 wt% or more, 10 wt% or more, or 15 wt% or more of the total weight of the pressure-sensitive adhesive layer. The amount of tackifier used can be, for example, 60 wt% or less, 40 wt% or less, or 30 wt% or less of the total weight of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive tape disclosed herein can also be preferably implemented in an embodiment in which a tackifier is substantially not used.

[0058] The pressure-sensitive adhesive layer may contain appropriate components (additives) that are acceptable for inclusion in the pressure-sensitive adhesive layer, as needed. Examples of such additives include antistatic agents, colorants (including pigments, dyes, etc.), fillers, antioxidants, and light stabilizers (including radical scavengers, UV absorbers, etc.). These additives may be used alone or in combination of two or more. The amount of each additive may be approximately the same as the amount typically used in the field of pressure-sensitive adhesive tapes.

[0059] (Formation of adhesive layer) The form of the PSA composition used to form the PSA layer in the technology disclosed herein is not particularly limited. The PSA layer may be formed, for example, from a water-dispersible PSA composition, a solvent-based PSA composition, a hot-melt PSA composition, or an active energy ray-curable PSA composition. The PSA layer can be formed in accordance with known methods for forming PSA layers in PSA tapes. For example, a method (direct method) in which the PSA composition is directly applied (typically coated) to a substrate and dried, or a method (transfer method) in which the PSA composition is applied to a surface with good releasability (e.g., the surface of a release liner, the backside of a release-treated substrate, etc.) and dried to form a PSA layer on the surface, and then the PSA layer is transferred to the substrate, can be used.

[0060] The thickness of the adhesive layer is not particularly limited and can be selected depending on the purpose and mode of use of the adhesive tape. The thickness of the adhesive layer can be appropriately set, for example, in the range of 10 μm to 800 μm. In the case of an adhesive tape that is expected to be attached to an adherend having an uneven surface (e.g., a paved surface), from the viewpoint of adhesion to the adherend (ability to penetrate into the unevenness), the thickness of the adhesive layer is suitably 20 μm or more, preferably 30 μm or more, more preferably 50 μm or more, and may be 70 μm or more, 80 μm or more, or 90 μm or more. Furthermore, from the viewpoint of productivity of the adhesive tape and suppression of blocking at the edge faces of the adhesive tape (particularly the edge faces along the longitudinal direction), in some embodiments, the thickness of the adhesive layer is suitably 500 μm or less, preferably 400 μm or less, and may be 300 μm or less, 200 μm or less, or 150 μm or less.

[0061] <Adhesive tape> The thickness of the pressure-sensitive adhesive tape disclosed herein is not particularly limited and can be selected depending on the purpose and mode of use of the pressure-sensitive adhesive tape. From the viewpoint of easily achieving both good conformability to rough surfaces such as road surfaces and durability, in some embodiments, the thickness of the pressure-sensitive adhesive tape may be, for example, 80 μm or more, suitably 120 μm or more, preferably 150 μm or more, or may be 250 μm or more, 450 μm or more, 650 μm or more, 850 μm or more, 1000 μm or more, or 1100 μm or more. The thickness of the pressure-sensitive adhesive tape may be, for example, 2500 μm or less. From the viewpoint of reducing the height of steps that occur on the adherend when the pressure-sensitive adhesive tape is applied, in some embodiments, the thickness of the pressure-sensitive adhesive tape is suitably 2000 μm or less, preferably 1800 μm or less, or may be 1600 μm or less, 1500 μm or less, or 1400 μm or less. Reducing the height of the step is also advantageous from the viewpoint of preventing chipping of the edge of the adhesive tape when it is attached to an adherend. For example, in a use mode in which a vehicle passes over an adhesive tape attached to a rough surface (such as a paved surface), it is beneficial to prevent chipping of the adhesive tape by reducing the height of the step to a predetermined level or less.

[0062] In some embodiments of the adhesive tape disclosed herein, the thickness T of the adhesive layer P [μm] and the thickness of the A layer, T A [μm] and the total thickness (T P +T A ) may be, for example, 60 μm or more, advantageously 100 μm or more, preferably 150 μm or more, more preferably 300 μm or more, may be 500 μm or more, may be 700 μm or more, or may be 800 μm or more. P +T A ), even if the adherend is a rough surface such as a paved surface, the adhesive tape tends to be easily adapted to the rough surface by utilizing the easy deformability of the adhesive layer and the plastic deformability of the A layer. Also, from the viewpoint of suppressing the height of the step that occurs on the adherend when the adhesive tape is applied, in some embodiments, P +TA ) is suitably 1800 μm or less, preferably 1500 μm or less, and may be 1300 μm or less, 1100 μm or less, or 1000 μm or less. From the viewpoint of suppressing blocking of the pressure-sensitive adhesive tape while exhibiting good conformability to a rough surface, in some embodiments, the thickness T P [μm] vs. A layer thickness T A [μm] ratio (T A / T P ) is preferably 1 or more, more preferably 3 or more, may be 5 or more, may be 6 or more, or may be 7 or more. From the viewpoint of increasing the 90-degree peel strength of the adhesive tape, the above ratio (T A / T P ) is suitably 30 or less, preferably 20 or less, may be 15 or less, may be 12 or less, or may be 10 or less.

[0063] (Tensile strength F T ) The adhesive tape disclosed herein has a tensile strength F T In some embodiments, the tensile strength F is 35 N / 15 mm or more and 145 N / 15 mm or less, for example, 40 N / 15 mm or more and 130 N / 15 mm or less. T is advantageously 40N / 15mm or more, preferably 45N / 15mm or more, more preferably 50N / 15mm or more, and may be 55N / 15mm or more, 60N / 15mm or more, 65N / 15mm or more, 70N / 15mm or more, or even 75N / 15mm or more. T is suitably 110N / 15mm or less, preferably 100N / 15mm or less or less than 100N / 15mm, and may be 95N / 15mm or less, 90N / 15mm or less, or 85N / 15mm or less. TIt is advantageous that the tensile strength F is not too high in order to effectively utilize the plastic deformation property of the A layer and improve the conformability of the adhesive tape as a whole to rough surfaces (e.g., paved surfaces). T can be adjusted by selecting the structure of the substrate, the composition of each layer, the method of manufacturing the substrate, etc.

[0064] Tensile strength of adhesive tape F T is measured based on JIS K 7127:1999. Specifically, the tensile strength F T The tensile strength F is measured by stretching a 15 mm wide test piece using a tensile tester under conditions of 23°C and 50% RH, with a chuck distance of 15 mm and a pulling speed of 300 mm / min until it breaks, and the maximum tensile load [N / 15 mm] at that time is measured. The test piece can be prepared, for example, by appropriately cutting the pressure-sensitive adhesive tape to be evaluated. The test piece has a tensile strength F T It is desirable to adjust the test piece so that the stretching direction of the test piece during measurement is the longitudinal direction of the adhesive tape (typically the machine direction (MD)). As a tensile tester, an "Autograph AGS-J" manufactured by Shimadzu Corporation can be used. The length of the test piece may be any length that can be set in the tensile tester with a chuck distance of 15 mm, and it is appropriate to set it to, for example, about 50 mm. A similar measurement method is also used in the examples described below.

[0065] Although not particularly limited, in the adhesive tape disclosed herein, the tensile strength F T The tensile strength F is measured by stretching the test piece in a direction perpendicular to the stretching direction of the test piece (typically, the width direction (TD) of the adhesive tape) until the test piece breaks. t can be, for example, 15 N / 15 mm or more (advantageously, 20 N / 15 mm or more). t is the tensile strength F except in the direction of extension of the test piece during measurement. T From the viewpoint of improving the durability of the pressure-sensitive adhesive tape, in some embodiments, the tensile strength F tis preferably 25N / 15mm or more, more preferably 30N / 15mm or more, may be 35N / 15mm or more, may be 40N / 15mm or more, may be 48N / 15mm or more, may be 50N / 15mm or more, or may be 55N / 15mm or more. t may be, for example, 200N / 15mm or less, and from the viewpoint of conformability etc., it is appropriate that it is 150N / 15mm or less, advantageously 140N / 15mm or less, preferably 120N / 15mm or less, more preferably 110N / 15mm or less, may be 100N / 15mm or less or less than 100N / 15mm, may be 95N / 15mm or less, may be 90N / 15mm or less, may be 85N / 15mm or less, may be 80N / 15mm or less, or may be 75N / 15mm or less. t can be adjusted by selecting the structure of the substrate, the composition of each layer, the method of manufacturing the substrate, etc.

[0066] Tensile strength F T [N / 15mm] and tensile strength F t Absolute value of the difference from [N / 15mm], i.e. |F T -F t is not particularly limited, but it is advantageous that it is not too large from the viewpoint of reducing the direction dependency in the plane direction and improving the performance stability. T -F t is preferably 20N / 15mm or less, more preferably 15N / 15mm or less, may be 11N / 15mm or less, or may be 9.0N / 15mm or less. T -F t Theoretically, the lower limit of |F is 0.0 N / 15 mm. From the practical viewpoint of productivity, cost, etc., in some embodiments, T -F t | may be, for example, 0.1 N / 15 mm or more, 0.2 N / 15 mm or more, 0.5 N / 15 mm or more, 1.0 N / 15 mm or more, 3.0 N / 15 mm or more, or 5.0 N / 15 mm or more. T and Ft The relative magnitude relationship with F T >F t F T =F t F T <F t In some preferred embodiments, F T ≧F t (Typically F T >F t The pressure-sensitive adhesive tapes according to the examples (Examples 1 to 8) described below all have F T -F t was in the range of 5.0 to 15N / 15mm.

[0067] (Tensile strength F B ) In some embodiments of the pressure-sensitive adhesive tape disclosed herein, the tensile strength F of layer B constituting the substrate of the pressure-sensitive adhesive tape B The tensile strength F is suitably 15N / 15mm or more, preferably 18N / 15mm or more, more preferably 20N / 15mm or more, may be 25N / 15mm or more, may be 28N / 15mm or more, or may be 30N / mm or more. B The layer B exhibiting the tensile strength F B The tensile strength F may be, for example, 75N / 15mm or less, and is suitably 70N / 15mm or less or less than 70N / 15mm from the viewpoint of avoiding impairing the plastic deformability of layer A, is advantageously 65N / 15mm or less, is preferably 60N / 15mm or less, and more preferably 58N / 15mm or less, and may be 55N / 15mm or less, or may be 50N / 15mm or less. B can be adjusted by selecting the composition, thickness, and formation method of the B layer.

[0068] Tensile strength of layer B F Bis measured as follows. That is, a single-layer resin film consisting of the B layer of the substrate is prepared. For example, a single-layer resin film having the same thickness as the B layer of the substrate is produced using the resin composition (b) that constitutes the B layer of the substrate. This resin film is the object of evaluation, and the tensile strength F of the adhesive tape is also measured. T Similarly, the tensile strength of layer B, F B The same measurement method is also used in the examples described below.

[0069] Although not particularly limited, the layer B constituting the substrate of the adhesive tape disclosed herein has the above tensile strength F B The tensile strength F is measured by stretching the test piece in a direction perpendicular to the direction in which the test piece is stretched (typically TD) until the test piece breaks. b may be, for example, 5.0 N / 15 mm or more (advantageously, 8.0 N / 15 mm or more). b is the tensile strength F except in the direction of extension of the test piece during measurement. B From the viewpoint of improving the durability of the pressure-sensitive adhesive tape, in some embodiments, the tensile strength F b is preferably 10N / 15mm or more, more preferably 15N / 15mm or more, may be 18N / 15mm or more, may be 20N / 15mm or more, may be 23N / 15mm or more, or may be 25N / 15mm or more. b may be, for example, 75N / 15mm or less, or 70N / 15mm or less, and from the viewpoint of conformability etc., it is advantageous to be 65N / 15mm or less, preferably 60N / 15mm or less or less than 60N / 15mm, more preferably 55N / 15mm or less, and may be 50N / 15mm or less, 48N / 15mm or less, or 46N / 15mm or less. b can be adjusted by selecting the composition, thickness, and formation method of the B layer.

[0070] Tensile strength F B [N / 15mm] and tensile strength F bAbsolute value of the difference from [N / 15mm], i.e. |F B -F b is not particularly limited. In order to reduce the direction dependency in the plane direction, in some embodiments, |F B -F b is preferably 10N / 15mm or less, more preferably 8.0N / 15mm or less, may be 6.0N / 15mm or less, may be 5.0N / 15mm or less, or may be 4.0N / 15mm or less. B -F b Theoretically, the lower limit of |F is 0 N / 15 mm. From the practical viewpoint of productivity, cost, etc., in some embodiments, B -F b | may be, for example, 0.1 N / 15 mm or more, 0.5 N / 15 mm or more, 1.0 N / 15 mm or more, 1.5 N / 15 mm or more, 2.0 N / 15 mm or more, 2.5 N / 15 mm or more, or 3.0 N / 15 mm or more. B and F b The relative magnitude relationship with F B >F b F B =F b F B <F b In some preferred embodiments, F B ≧F b (Typically F B >F b The layer B constituting the substrate of the pressure-sensitive adhesive tape according to the examples (Examples 1 to 8) described later is F. B -F b was in the range of 2.0 to 5.0 N / 15 mm.

[0071] In some embodiments of the adhesive tape disclosed herein, the adhesive tape satisfies the following inequality (1): (F B / T B )>(F T / T S ) (1); In the above inequality (1), it is preferable that T B is the thickness of the B layer [μm], and T S is the thickness of the substrate [μm]. That is, the tensile strength of layer B, F B [N / 15mm] is the thickness of layer B, T B The value divided by [μm] is the tensile strength F of the adhesive tape. B [N / 15mm] is the thickness of the substrate T S It is preferable that the value is larger than the value obtained by dividing by [μm]. B is the numerical part of the thickness of the B layer expressed in μm, and T B It is a dimensionless number with no unit. F in the above inequality (1) T , T B , T S The same is true for (1). Furthermore, the reason why the denominator on the right-hand side of the above inequality (1) is the thickness of the substrate rather than the thickness of the adhesive tape is because, in general, the tensile strength of the adhesive layer is significantly smaller than the tensile strength of the substrate, and therefore the tensile strength of the adhesive tape can be understood as an approximation of the tensile strength of the substrate. In other words, the above inequality (1) shows that when the tensile strength of the substrate (approximate to the tensile strength of the adhesive tape) and the tensile strength of Layer B are each converted to a value per thickness, the presence of Layer B increases the tensile strength of the entire substrate.

[0072] (sagging) In some embodiments of the pressure-sensitive adhesive tape disclosed herein, the pressure-sensitive adhesive tape preferably has a sag of 55 mm or more. Higher sag of a pressure-sensitive adhesive tape indicates that the pressure-sensitive adhesive tape is more easily deformed. Therefore, a pressure-sensitive adhesive tape with a sag of 55 mm or more can effectively conform the entire pressure-sensitive adhesive tape to the irregularities of the adherend surface by utilizing the plastic deformability of Layer A of the substrate. The sag is more preferably 58 mm or more, even more preferably 60 mm or more or more than 60 mm, and may be 62 mm or more or 64 mm or more. On the other hand, from the viewpoint of the durability of the pressure-sensitive adhesive tape, it is advantageous for the sag not to be too high. From this viewpoint, in some embodiments, the sag is suitably 80 mm or less, advantageously 78 mm or less or 75 mm or less, preferably less than 75 mm, and may be 73 mm or less, 70 mm or less, or 68 mm or less. The sag can be adjusted by selecting the structure of the substrate, the composition of each layer, the method of manufacturing the substrate, the thickness of the pressure-sensitive adhesive tape, etc.

[0073] The sagging of a pressure-sensitive adhesive tape is measured as follows. Specifically, in an environment of 23°C and 50% RH, a test piece 50 mm wide and 300 mm long is cantilevered on a horizontal holder with the pressure-sensitive adhesive layer side facing downwards (the adhesive surface) so that a 100 mm length from one end of the test piece extends outward from the holder, and after leaving the test piece standing for 10 minutes, the difference in height between the top surface of the holder and one end of the test piece is measured. The test piece can be prepared, for example, by appropriately cutting the pressure-sensitive adhesive tape to be evaluated. It is desirable to prepare the test piece so that the longitudinal direction of the test piece coincides with the longitudinal direction of the pressure-sensitive adhesive tape. 2, a test piece 32 having a width of 50 mm and a length of 300 mm is attached to the upper surface of the holding table 30 so that a 100 mm length from one end 32A of the test piece 32 extends outward from the horizontal holding table 30, perpendicular to the outer edge of the table 30, and a 200 mm length from the other end 32B of the test piece 32 is attached thereto, and a weight 34 is placed on top of the test piece 32 to hold the test piece 32 cantilevered on the holding table 30. After leaving the test piece 32 to stand for 10 minutes, the difference in height (sagging height) L1 between the upper surface of the holding table 32 and one end 32A of the test piece 32 is measured, and this value is taken as the measurement value of sagging [mm].

[0074] (90 degree peel strength) In some embodiments of the pressure-sensitive adhesive tape disclosed herein, the pressure-sensitive adhesive tape suitably has a 90-degree peel strength from a stainless steel plate (hereinafter also simply referred to as "90-degree peel strength") of 5.0 N / 20 mm or more, advantageously 7.0 N / 20 mm or more, and preferably 10.0 N / 20 mm or more. From the viewpoint of improving peel resistance, in some embodiments, the 90-degree peel strength of the pressure-sensitive adhesive tape may be 13.0 N / 20 mm or more, 15.0 N / 20 mm or more, or even 18.0 N / 20 mm or more. The upper limit of the 90-degree peel strength is not particularly limited, and may be, for example, 80 N / 20 mm or less. In some embodiments, from the viewpoint of ease of peeling when peeling a pressure-sensitive adhesive tape attached to an adherend from the adherend and replacing it with a new pressure-sensitive adhesive tape, the 90-degree peel strength may be, for example, 45 N / 20 mm or less, 30 N / 20 mm or less, or 25 N / 20 mm or less.

[0075] The 90-degree peel strength of an adhesive tape is measured as follows. Specifically, a measurement sample cut into a 20 mm wide strip is pressed against the surface of a stainless steel plate (SUS 304BA plate) by rolling a 2 kg roller back and forth once under an environment of 23°C and 50% RH. After leaving the sample in the same environment for 30 minutes, the peel strength (N / 20 mm) is measured using a tensile tester in accordance with JIS Z 0237:2000 at a pulling speed of 300 mm / min and a peel angle of 90°. As a tensile tester, for example, the "Autograph AGS-J" manufactured by Shimadzu Corporation can be used. Measurements are also made in the examples described below using a similar method.

[0076] <Application> The adhesive tape disclosed herein can be preferably used in an embodiment in which it is attached to a rough surface such as a paved surface (particularly an outdoor paved surface) by taking advantage of its feature of being able to improve the service life even in an embodiment in which the adhesive tape is attached to a rough surface and is frequently subjected to strong stress from above. The paved surface can be, for example, an asphalt pavement, a concrete pavement, a concrete block pavement, or the like. The application effects of the technology disclosed herein can be suitably exhibited in an embodiment in which vehicles (e.g., passenger cars, trucks, forklifts, reach stackers, etc.) pass across the adhesive tape attached to the paved surface. Furthermore, taking advantage of the above-mentioned features, the adhesive tape disclosed herein can be preferably used, for example, as an adhesive tape for marking, which is suitable for applications such as being stuck on factory premises or roads to indicate no-entry zones or pallet storage areas, marking markers such as vehicle stopping positions or parking lot boundaries, marking information such as destination signs, and forming tiger patterns to attract attention at construction sites or train stations. Furthermore, the adhesive tape disclosed herein is not limited to applications in which it is attached to paved surfaces, but is also useful for applications in which it is attached to, for example, indoor or outdoor mortar-coated surfaces, block walls, brick walls, stone walls, stone-paved roads, etc.

[0077] Several examples of the present invention will be described below, but it is not intended that the present invention be limited to those shown in these examples. In the following description, "parts" and "%" are by weight unless otherwise specified.

[0078] <Materials used> The materials used to prepare the adhesive tapes in the following experiments are as follows. PET: Polyethylene terephthalate (PET) film available from Nisshin Chemicals, trade name "Diafoil S100". EVA: Tosoh's "Ultrathene 636" (ethylene-vinyl acetate copolymer, vinyl acetate content 19%) and Mitsui Dow Polychemical's "Evaflex EV40LX" (ethylene-vinyl acetate copolymer, vinyl acetate content 41%) were used in a 1:1 weight ratio. Polyolefin resin: Polyethylene (linear low-density polyethylene manufactured by Tosoh Corporation, product name "Nipolon-L F21") and α-olefin copolymer (ethylene-α-olefin copolymer manufactured by Mitsui Chemicals, product name "Tafmer A 4070S") were used in a 1:1 weight ratio. In Table 1, this is abbreviated as "polyolefin." Filler: Calcium carbonate (manufactured by Takehara Chemical Industry, average particle size 4.5 μm). Adhesive composition: Toyochem's two-component curing acrylic solvent-based adhesive. Just before use, mix 0.02 parts of epoxy crosslinking agent as a curing agent with 100 parts of base material containing 40-50% acrylate ester copolymer and 5-15% tackifying resin in organic solvent (both on a non-volatile basis).

[0079] Example 1 Using the raw material for Layer A, which contained 50% EVA and 50% filler, and the raw material for Layer B, which contained 67% polyolefin resin and filler, a two-layer resin film (substrate) consisting of an 800 μm thick Layer A and a 400 μm thick Layer B was produced by calendaring. A release liner was prepared, with one side of a 38 μm-thick PET film being a release surface made of a silicone-based release agent. The above-mentioned adhesive composition was applied to the release surface of this release liner and dried at 100° C. for 2 minutes to form an adhesive layer with a thickness of 100 μm. This adhesive layer was attached to the first side (the surface on the Layer A side) of the resin film to obtain an adhesive tape according to this example.

[0080] <Examples 2 to 5, Comparative Example 1> The adhesive tapes according to each example were produced in the same manner as in Example 1, except that the compositions of the raw materials for the A layer and the B layer used to produce the substrate were as shown in Table 1.

[0081] <Comparative Examples 2 and 3> A T-die film molding machine was used to melt-knead and extrude the raw materials for Layer A having the composition shown in Table 1 below to produce a 1200 μm-thick resin film having a single-layer structure consisting of Layer A. Pressure-sensitive adhesive tapes according to each example were produced in the same manner as in Example 1, except that the above resin film was used as the substrate.

[0082] <Comparative Example 4> An adhesive tape according to this example was produced in the same manner as in Example 1, except that a 205 μm thick PET film (Nisshin Chemical Industries, trade name "Diafoil S100") was used as the substrate.

[0083] <Comparative Example 5> A two-layer resin film (substrate) was produced by melt-kneading the raw materials for Layer A having the composition shown in Table 1, and extrusion-laminated the 800 μm thick Layer A onto one side of a 38 μm thick PET film (Nisshin Chemicals, product name "Diafoil S100") serving as Layer B. The pressure-sensitive adhesive tape of this example was produced in the same manner as in Example 1, except that this resin film was used as the substrate.

[0084] <Examples 6 to 8, Comparative Example 6> The adhesive tapes according to each example were produced in the same manner as in Example 3, except that the composition of the raw material for layer A used to produce the substrate was as shown in Table 2.

[0085] <Measurement and Evaluation> The tensile strength F of the obtained adhesive tape was measured by the above-mentioned method. T [N / 15mm], sag [mm], and tensile strength F of layer B B The results are shown in Tables 1 and 2.

[0086] (Road compatibility test) The adhesive tape according to each example was applied to an outdoor asphalt-paved road surface (road surface) in a size of 50 mm wide and 3 m long while the road surface was dry. Specifically, the adhesive tape was placed on the road surface and lightly pressed by hand, then struck from above (i.e., from the backside of the adhesive tape) with a hammer, and then a vehicle (Toyota L&F electric forklift, model number 8FBR15, made one round trip at approximately 2 km / h) was driven to adhere the tape to the road surface. The degree of penetration (conformity) of the adhesive tape into the unevenness of the road surface was then observed, and the road surface conformability was evaluated using the following three criteria. The results are shown in Tables 1 and 2. AA: It is clear from the back of the tape that the adhesive tape conforms to the unevenness (undulations) of the road surface (excellent conformability). A: When you rub the back of the adhesive tape with your hand, you can feel the unevenness of the road surface (good conformability). B: When the back of the adhesive tape is rubbed with the hand, the unevenness of the road surface cannot be felt (poor conformability).

[0087] (Durability test) In the same manner as in the road surface conformability test, adhesive tapes of each example were applied to an outdoor asphalt-paved road surface in a width of 50 mm and a length of 3 m. After leaving the tape for one month in an environment where approximately 20 trucks per day passed across the tape, the degree of damage to the tape was observed and durability was evaluated using the following three levels. The results are shown in Tables 1 and 2. AA: No obvious tears or chips in the adhesive tape (excellent durability) A: There is some chipping on the side edge of the adhesive tape, but the marking function is still sufficient (good durability). B: The adhesive tape is torn and the marking function is clearly impaired (poor durability)

[0088] The 90-degree peel strength of the pressure-sensitive adhesive tape of Example 3 was 20.6 N / 20 mm, and the 90-degree peel strengths of the pressure-sensitive adhesive tapes of the other Examples were approximately the same.

[0089] [Table 1]

[0090] [Table 2]

[0091] As shown in Tables 1 and 2, all of the pressure-sensitive adhesive tapes of Examples 1 to 8 exhibited good road conformability and good durability. The pressure-sensitive adhesive tapes of Examples 2 to 4, 7, and 8 showed particularly good results. Furthermore, the Examples using a polyolefin resin as the base resin of Layer B exhibited better antifouling properties in visual observation after the durability test. On the other hand, Comparative Examples 1 and 6, in which the filler content of Layer A was too low, exhibited poor road conformability. Furthermore, a comparison of Examples 2 and 3 with Comparative Example 5, in which the composition and thickness of Layer A are the same, reveals that the road conformability of Layer A is impaired depending on the selection of Layer B. The pressure-sensitive adhesive tapes of Comparative Examples 2 to 4, which used a substrate with a single-layer structure, were insufficient in either or both of road conformability and durability. Furthermore, when a pressure-sensitive adhesive tape was produced using a 1,200 μm-thick single-layer structure substrate formed from the raw material for Layer A of Example 3 instead of the substrate (two-layer structure substrate) of the pressure-sensitive adhesive tape of Example 3, the durability was evaluated in the same manner as above, and it was confirmed that the durability was insufficient (evaluation result: B).

[0092] Although specific examples of the present invention have been described above in detail, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and alterations of the specific examples exemplified above. [Explanation of symbols]

[0093] 1 adhesive tape 10 Base material 10A 1st side 10B 2nd side (back) 12 A layer 14 B layer 20 adhesive layer 20A surface (adhesive surface) 30 Holding stand 32 test specimens 32A one end 32B other end 34 Weight L1 Hanging height

Claims

1. An adhesive tape comprising: a substrate having a first surface and a second surface; and an adhesive layer disposed on the first surface of the substrate; The substrate includes at least a layer A made of a resin composition (a) and constituting the first surface, and a layer B made of a resin composition (b) and arranged closer to the second surface than the layer A, The resin composition (a) contains an ethylene-vinyl acetate copolymer as a base resin, The resin composition (a) contains 50% by weight or more of a filler, The adhesive tape has a tensile strength F measured as the maximum tensile load [N / 15 mm] when a 15 mm wide test piece is stretched to break using a tensile tester under conditions of a chuck distance of 15 mm and a tensile speed of 300 mm / min under an environment of 23°C and 50% RH. Ｔ An adhesive tape having a strength of 35N / 15mm or more and 145N / 15mm or less.

2. The pressure-sensitive adhesive tape according to claim 1 , wherein the pressure-sensitive adhesive tape has a sag of 55 mm or more as measured by the following method. [Sagging measurement] In an environment of 23°C and 50% RH, a test piece having a width of 50 mm and a length of 300 mm is held in a cantilever on a horizontal holding stand with the side having the adhesive layer facing downwards so that a range from one end of the test piece to a length of 100 mm extends outward from the holding stand, and after leaving it to stand for 10 minutes, the difference in height between the upper surface of the holding stand and one end of the test piece is measured.

3. The pressure-sensitive adhesive tape according to claim 1 or 2, wherein the resin composition (a) contains an elastomer as a base resin.

4. The pressure-sensitive adhesive tape according to any one of claims 1 to 3, wherein the resin composition (b) contains a polyolefin resin as a base resin.

5. The thickness T of the B layer Ｂ [μm] to the thickness T of the A layer Ａ [μm] ratio (T Ａ / T Ｂ 5. The pressure-sensitive adhesive tape according to claim 1, wherein the value of (a) is 0.5 or more and 10 or less.

6. The pressure-sensitive adhesive tape according to any one of claims 1 to 5, wherein the thickness of the pressure-sensitive adhesive tape is 2000 µm or less.

7. The thickness T of the pressure-sensitive adhesive layer Ｐ [μm] and the thickness T of the A layer Ａ [μm] and the total thickness (T Ｐ +T Ａ 7. The pressure-sensitive adhesive tape according to claim 1, wherein the thickness of the adhesive tape is 150 μm or more.

8. The pressure-sensitive adhesive tape according to any one of claims 1 to 7, wherein the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer.

9. The pressure-sensitive adhesive tape according to any one of claims 1 to 8, which is used by being attached to an outdoor paved surface.

10. An adhesive tape described in any one of claims 1 to 9, wherein the vinyl acetate content of the ethylene-vinyl acetate copolymer is 5 to 50% by weight.

11. A marking adhesive tape comprising the adhesive tape according to any one of claims 1 to 10.

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