JP2015003944A - Adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive sheet, with both surfaces of an adhesive layer in an adhesive sheet made to be rough without using a conventional method for adjusting surface roughness of the adhesive layer, so as to allow a control of an initial adhesive force of both surfaces of the adhesive layer.SOLUTION: An adhesive sheet includes an acrylic adhesive layer (B), a release layer (A1) formed on one side of the acrylic adhesive layer (B), and a release layer (A2) formed on the other side of the acrylic adhesive layer (B). Each of the release layer (A1) and the release layer (A2) contains 0.1-20 wt.% fine particles (P) whose average particle diameter is 4-25 μm.

Description

  The present invention relates to an adhesive sheet. More specifically, the present invention relates to an adhesive sheet having release layers on both sides of the adhesive layer.

  In recent years, in the pressure sensitive adhesive sheet, it is desired to adjust the surface roughness of the pressure sensitive adhesive layer and the back surface layer in accordance with the purpose (particularly, control of initial adhesive strength and appearance adjustment).

  As a method for adjusting the surface roughness, there is known a T-die extrusion touch roll forming method, that is, a method in which a molten resin extruded by a T-die is brought into contact with a metal roll having an uneven pattern, and the uneven pattern is transferred to the resin surface. (For example, Patent Documents 1 and 2).

  However, in the T-die extrusion touch roll molding method, if high-speed molding is performed, there is a problem of processing failure such that the molten resin is wound around the metal roll due to insufficient cooling of the resin, or the uneven pattern of the metal roll is sufficiently transferred to the resin. The problem that it is not done arises.

  Examples of methods for adjusting the surface roughness other than the T-die extrusion touch roll molding method include a T-die air knife molding method and an inflation air cooling molding method. However, in these methods, since unevenness is formed only by flow deformation from when the resin is melted to when it is cooled and solidified, it is difficult to form precise unevenness.

JP 2001-234146 A JP 2002-97238 A

  The present invention has been made to solve the above-described conventional problems, and the object of the present invention is to use the conventional method for adjusting the surface roughness of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet, without using the conventional method. An object of the present invention is to provide a pressure-sensitive adhesive sheet in which the surfaces on both sides of the pressure-sensitive adhesive layer are roughened, and thus the initial pressure-sensitive adhesive force on the surfaces on both sides of the pressure-sensitive adhesive layer can be controlled.

  The present inventor has studied to solve the above-mentioned problems, and makes a pressure-sensitive adhesive sheet having a release layer on both sides of the pressure-sensitive adhesive layer, and contains a specific amount of fine particles with a specific content in the release layer. Thus, it was found that the above problems can be solved.

The pressure-sensitive adhesive sheet of the present invention is
Acrylic pressure-sensitive adhesive layer (B), a release layer (A1) provided on one side of the acrylic pressure-sensitive adhesive layer (B), and a release layer provided on the other side of the acrylic pressure-sensitive adhesive layer (B) A pressure-sensitive adhesive sheet having (A2),
The release layer (A1) and the release layer (A2) each contain 0.1% to 20% by weight of fine particles (P) having an average particle diameter of 4 μm to 25 μm.

  In a preferred embodiment, the arithmetic average surface roughness Ra1 of the interface between the release layer (A1) and the acrylic pressure-sensitive adhesive layer (B), and the release layer (A2) and the acrylic pressure-sensitive adhesive layer (B) The arithmetic average surface roughness Ra2 of the interface is 0.15 μm to 0.60 μm, respectively.

  In preferable embodiment, the said acrylic adhesive layer (B) contains the acrylic block copolymer containing an acrylate block structure and a methacrylic ester block structure.

  In a preferred embodiment, the acrylic block copolymer has a weight average molecular weight of 30,000 to 300,000.

  In a preferred embodiment, the release layer (A1) and the release layer (A2) each contain a polyolefin resin.

  In a preferred embodiment, the pressure-sensitive adhesive sheet of the present invention is integrated by coextrusion molding.

  According to the present invention, the surface on both sides of the pressure-sensitive adhesive layer is roughened without using a conventional method for adjusting the surface roughness of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet. It is possible to provide an adhesive sheet in which the initial adhesive force on the surfaces on both sides of the layer can be controlled.

It is a schematic sectional drawing of the adhesive sheet by preferable embodiment of this invention. It is the schematic which shows another adhesive sheet by preferable embodiment of this invention. It is the schematic which shows another adhesive sheet by preferable embodiment of this invention.

≪≪Adhesive sheet≫≫
The pressure-sensitive adhesive sheet of the present invention comprises an acrylic pressure-sensitive adhesive layer (B), a release layer (A1) provided on one side of the acrylic pressure-sensitive adhesive layer (B), and the other of the acrylic pressure-sensitive adhesive layer (B). It is an adhesive sheet having a release layer (A2) provided on one side. The pressure-sensitive adhesive sheet of the present invention comprises an acrylic pressure-sensitive adhesive layer (B), a release layer (A1) provided on one side of the acrylic pressure-sensitive adhesive layer (B), and the other of the acrylic pressure-sensitive adhesive layer (B). As long as it is a pressure-sensitive adhesive sheet having a release layer (A2) provided on one side, it may have any other appropriate layer as long as the effects of the present invention are not impaired. The release layer (A1) may be only one layer or may be composed of two or more layers. The release layer (A2) may be only one layer or may be composed of two or more layers. The acrylic pressure-sensitive adhesive layer (B) may be only one layer or may be composed of two or more layers.

  FIG. 1 is a schematic cross-sectional view of an adhesive sheet according to a preferred embodiment of the present invention. The pressure-sensitive adhesive sheet 100 shown in FIG. 1 includes an acrylic pressure-sensitive adhesive layer (B) 20, a release layer (A1) 11 provided on one side of the acrylic pressure-sensitive adhesive layer (B) 20, and the acrylic pressure-sensitive adhesive layer (B ) 20 and the release layer (A2) 12 provided on the other side. The release layer (A1) 11 includes fine particles (P) 50. The release layer (A2) 12 includes fine particles (P) 50. Thus, the pressure-sensitive adhesive sheet according to a preferred embodiment of the present invention includes an acrylic pressure-sensitive adhesive layer (B), a release layer (A1) provided on one side of the acrylic pressure-sensitive adhesive layer (B), and the acrylic sheet. It consists of a peeling layer (A2) provided on the other side of the pressure-sensitive adhesive layer (B). The fine particles (P) contained in the release layer (A1) 11 and the fine particles (P) contained in the release layer (A2) 12 may be the same kind of fine particles or different kinds of fine particles. Further, the fine particles (P) 50 contained in the release layer (A1) 11 may be only one kind or two or more kinds. Further, the fine particles (P) 50 contained in the release layer (A2) 12 may be only one type or two or more types.

  FIG. 2 is a schematic cross-sectional view of another pressure-sensitive adhesive sheet according to a preferred embodiment of the present invention. 2 includes an acrylic pressure-sensitive adhesive layer (B) 20, a release layer (A1) 11 provided on one side of the acrylic pressure-sensitive adhesive layer (B) 20, and the acrylic pressure-sensitive adhesive layer (B ) And a release layer (A2) 12 provided on the other side of 20, and another release layer (A1) on the opposite side of the release layer (A1) 11 from the acrylic pressure-sensitive adhesive layer (B) 20. ') It has 31. The release layer (A1) 11 includes fine particles (P) 50. The release layer (A2) 12 includes fine particles (P) 50. In the pressure-sensitive adhesive sheet 100 shown in FIG. 2, the release layer (A1) 11 has only one separate release layer (A1 ′) 31 on the opposite side of the acrylic pressure-sensitive adhesive layer (B) 20. The layer (A1 ′) 31 may have two or more layers. Thus, another pressure-sensitive adhesive sheet according to a preferred embodiment of the present invention includes an acrylic pressure-sensitive adhesive layer (B), a release layer (A1) provided on one side of the acrylic pressure-sensitive adhesive layer (B), A release layer (A2) provided on the other side of the acrylic pressure-sensitive adhesive layer (B) and another release provided on the opposite side of the release layer (A1) from the acrylic pressure-sensitive adhesive layer (B) Layer (A1 ′). The fine particles (P) contained in the release layer (A1) 11 and the fine particles (P) contained in the release layer (A2) 12 may be the same kind of fine particles or different kinds of fine particles. Further, the fine particles (P) 50 contained in the release layer (A1) 11 may be only one kind or two or more kinds. Further, the fine particles (P) 50 contained in the release layer (A2) 12 may be only one type or two or more types.

  FIG. 3 is a schematic cross-sectional view of still another pressure-sensitive adhesive sheet according to a preferred embodiment of the present invention. The pressure-sensitive adhesive sheet 100 shown in FIG. 3 includes an acrylic pressure-sensitive adhesive layer (B) 20, a release layer (A1) 11 provided on one side of the acrylic pressure-sensitive adhesive layer (B) 20, and the acrylic pressure-sensitive adhesive layer (B ) And a release layer (A2) 12 provided on the other side of 20, and another release layer (A1) on the opposite side of the release layer (A1) 11 from the acrylic pressure-sensitive adhesive layer (B) 20. ') 31 and another release layer (A2') 32 on the opposite side of the release layer (A2) 12 from the acrylic pressure-sensitive adhesive layer (B) 20. The release layer (A1) 11 includes fine particles (P) 50. The release layer (A2) 12 includes fine particles (P) 50. In the pressure-sensitive adhesive sheet 100 shown in FIG. 3, the release layer (A1) 11 has only one release layer (A1 ′) 31 on the opposite side of the acrylic pressure-sensitive adhesive layer (B) 20. The layer (A1 ′) 31 may have two or more layers. 3 has only one release layer (A2 ′) 32 on the opposite side of the release layer (A2) 12 from the acrylic adhesive layer (B) 20. The release layer (A2 ′) 32 may have two or more layers. Thus, another pressure-sensitive adhesive sheet according to a preferred embodiment of the present invention includes an acrylic pressure-sensitive adhesive layer (B), a release layer (A1) provided on one side of the acrylic pressure-sensitive adhesive layer (B), A release layer (A2) provided on the other side of the acrylic pressure-sensitive adhesive layer (B) and another release provided on the opposite side of the release layer (A1) from the acrylic pressure-sensitive adhesive layer (B) It consists of a layer (A1 ′) and another release layer (A2 ′) provided on the opposite side of the release layer (A2) from the acrylic pressure-sensitive adhesive layer (B). The fine particles (P) contained in the release layer (A1) 11 and the fine particles (P) contained in the release layer (A2) 12 may be the same kind of fine particles or different kinds of fine particles. Further, the fine particles (P) 50 contained in the release layer (A1) 11 may be only one kind or two or more kinds. Further, the fine particles (P) 50 contained in the release layer (A2) 12 may be only one type or two or more types.

  In the pressure-sensitive adhesive sheet of the present invention, the arithmetic average surface roughness Ra1 of the interface between the release layer (A1) and the acrylic pressure-sensitive adhesive layer (B), and the interface between the release layer (A2) and the acrylic pressure-sensitive adhesive layer (B) The arithmetic average surface roughness Ra2 is preferably 0.15 μm to 0.60 μm, more preferably 0.20 μm to 0.60 μm, and still more preferably 0.25 μm to 0.60 μm. By adjusting the arithmetic average surface roughness Ra1 and Ra2 within the above range, the surfaces on both sides of the acrylic pressure-sensitive adhesive layer (B) can be effectively roughened, and the acrylic pressure-sensitive adhesive layer (B It is possible to provide a pressure-sensitive adhesive sheet that can effectively control the initial pressure-sensitive adhesive strength of the surfaces on both sides.

  The thickness of the pressure-sensitive adhesive sheet of the present invention can be set to any appropriate thickness depending on the application. The thickness of the pressure-sensitive adhesive sheet of the present invention is preferably 2 μm to 500 μm, more preferably 5 μm to 300 μm, and still more preferably 10 μm to 200 μm.

<< Peeling layer (A1) and peeling layer (A2) >>
In the pressure-sensitive adhesive sheet of the present invention, the release layer (A1) is provided on one side of the acrylic pressure-sensitive adhesive layer (B). The release layer (A2) is provided on the other side of the acrylic pressure-sensitive adhesive layer (B) in the pressure-sensitive adhesive sheet of the present invention.

  The release layer (A1) and the release layer (A2) are typically non-tacky at 23 ° C., respectively.

  The release layer (A1) and the release layer (A2) are preferably each a layer that can function as a release liner for the acrylic pressure-sensitive adhesive layer (B). For example, it is preferable that the release layer (A1) and the release layer (A2) can be peeled from the acrylic pressure-sensitive adhesive layer (B), respectively. Moreover, it is preferable that the peeling layer (A1) and the peeling layer (A2) can be continuously peeled off from the acrylic pressure-sensitive adhesive layer (B) without tearing or breaking in the middle.

  Arbitrary appropriate thickness can be employ | adopted for the thickness of a peeling layer (A1) and a peeling layer (A2) according to a use. The thicknesses of the release layer (A1) and the release layer (A2) are preferably 3 μm to 300 μm, more preferably 5 μm to 200 μm, still more preferably 7 μm to 100 μm, and particularly preferably 10 μm to 50 μm. is there. If the release layer (A1) and the release layer (A2) are too thin, the surface of the acrylic pressure-sensitive adhesive layer (B) may not be sufficiently roughened. If the release layer (A1) and the release layer (A2) are too thick, for example, it may be difficult to obtain the pressure-sensitive adhesive sheet of the present invention integrally by coextrusion molding.

  Each of the release layer (A1) and the release layer (A2) may be composed of only one layer, or may be composed of two or more layers. When the release layer (A1) and the release layer (A2) are composed of only one layer, coextrusion molding can be facilitated. When the release layer (A1) and the release layer (A2) are composed of two or more layers, the functions can be divided by each layer.

  Each of the release layer (A1) and the release layer (A2) preferably contains a polyolefin resin as a resin component. Any appropriate polyolefin resin can be adopted as the polyolefin resin as long as it can be co-extruded. The content ratio of the polyolefin resin in the resin component of the release layer (A1) is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, and further preferably 90% by weight to 100% by weight, particularly preferably 95% by weight to 100% by weight, and most preferably substantially 100% by weight. The content ratio of the polyolefin resin in the resin component of the release layer (A2) is preferably 50% by weight to 100% by weight, more preferably 70% by weight to 100% by weight, and still more preferably 90% by weight or more. 100% by weight, particularly preferably 95% by weight to 100% by weight, and most preferably substantially 100% by weight.

  The polyolefin resin is preferably an α-olefin homopolymer, a copolymer of two or more α-olefins, block polypropylene, random polypropylene, one or more α-olefins and other vinyl monomers. A copolymer is mentioned. Examples of the form of the copolymer include a block form and a random form.

  More specifically, the polyolefin resin is more preferably polyethylene (PE), homopolypropylene (PP), block polypropylene, or random polypropylene.

  The α-olefin is preferably an α-olefin having 2 to 12 carbon atoms. Examples of such α-olefins include ethylene, propylene, 1-butene, 4-methyl-1-pentene and the like.

  Examples of the α-olefin homopolymer include polyethylene (PE), homopolypropylene (PP), poly (1-butene), poly (4-methyl-1-pentene), and the like.

  Examples of polyethylene (PE) include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), medium density polyethylene, and high density polyethylene (HDPE).

  The structure of homopolypropylene may be any of isotactic, atactic and syndiotactic.

  Examples of the copolymer of two or more kinds of α-olefins include, for example, an ethylene / propylene copolymer, an ethylene / 1-butene copolymer, an ethylene / propylene / 1-butene copolymer, and an ethylene / carbon atom number of 5 to 5. 12 α-olefin copolymers, propylene / α-olefin copolymers having 5 to 12 carbon atoms, and the like.

  Examples of the copolymer of one or more α-olefins and other vinyl monomers include, for example, ethylene / vinyl acetate copolymer, ethylene / acrylic acid alkyl ester copolymer, and ethylene / methacrylic acid alkyl ester copolymer. And an ethylene-nonconjugated diene copolymer.

  When the release layer (A1) and the release layer (A2) each contain a polyolefin resin, the polyolefin resin may be only one type or two or more types. When each of the release layer (A1) and the release layer (A2) contains two or more types of polyolefin resins, examples of the form include blend and copolymerization.

  A commercially available product may be used as the polyolefin resin.

  The release layer (A1) and the release layer (A2) can each contain any appropriate additive as necessary. Examples of additives that can be contained in the release layer (A1) and release layer (A2) include a mold release agent, an ultraviolet absorber, a heat stabilizer, a filler, a lubricant, a colorant (such as a dye), and an antioxidant. , Anti-scratch agent, anti-blocking agent, foaming agent, polyethyleneimine and the like. The kind, number, and amount of additives contained in the release layer (A1) and release layer (A2) can be appropriately set depending on the purpose.

  Examples of the release agent include fatty acid amide release agents, silicone release agents, fluorine release agents, long chain alkyl release agents, and the like. From the viewpoint of being able to form a release layer with a better balance between releasability and contamination due to bleed-out, a fatty acid amide release agent is preferred, and a saturated fatty acid bisamide is more preferred. Arbitrary appropriate content can be employ | adopted for content of a mold release agent. Typically, when a release agent is contained in the release layer (A1), it is preferably 0.01% by weight to 5% by weight, and when a release agent is contained in the release layer (A2), preferably 0. 0.01% to 5% by weight.

  Examples of the ultraviolet absorber include benzotriazole compounds, benzophenone compounds, benzoate compounds, and the like. Any appropriate content can be adopted as the content of the ultraviolet absorber as long as it does not bleed out during molding. Typically, when the release layer (A1) contains an ultraviolet absorber, it is preferably 0.01% by weight to 5% by weight, and when the release layer (A2) contains an ultraviolet absorber, preferably 0%. 0.01% to 5% by weight.

  Examples of the heat resistance stabilizer include hindered amine compounds, phosphorus compounds, and cyanoacrylate compounds. Any appropriate content can be adopted as the content of the heat-resistant stabilizer as long as it does not bleed out during molding. Typically, when the heat-resistant stabilizer is included in the release layer (A1), preferably 0.01 wt% to 5 wt%, and preferably when the heat-resistant stabilizer is included in the release layer (A2). Is 0.01 wt% to 5 wt%.

  Examples of the filler include inorganic fillers such as talc, titanium oxide, calcium oxide, magnesium oxide, zinc oxide, titanium oxide, calcium carbonate, silica, clay, mica, barium sulfate, whisker, and magnesium hydroxide. The average particle diameter of the filler is preferably 0.1 μm to 10 μm. The content of the filler is preferably 1% by weight to 200% by weight when the filler is contained in the release layer (A1), and preferably 1% by weight when the filler is contained in the release layer (A2). ~ 200% by weight.

  The release layer (A1) and the release layer (A2) each contain 0.1% by weight to 20% by weight of fine particles (P) having an average particle diameter of 4 μm to 25 μm. Each of the release layer (A1) and the release layer (A2) contains fine particles (P) having such a specific size in a specific content ratio, so that the release layer is in the vicinity of the surface of the release layer (A1). Fine particles (P) that can form moderate irregularities such that the arithmetic average surface roughness Ra1 of the interface between (A1) and the acrylic pressure-sensitive adhesive layer (B) can be adjusted in the range of 0.15 μm to 0.60 μm. In the vicinity of the surface of the release layer (A2), the arithmetic average surface roughness Ra2 of the interface between the release layer (A2) and the acrylic pressure-sensitive adhesive layer (B) is in the range of 0.15 μm to 0.60 μm. Fine particles (P) that can form moderate irregularities that can be adjusted can be present. Therefore, when the peeling layer (A1) is peeled from the acrylic pressure-sensitive adhesive layer (B), the arithmetic average surface roughness Ra1 of the peeling surface on the peeling layer (A1) side of the acrylic pressure-sensitive adhesive layer (B) is 0. When the release layer (A2) is peeled from the acrylic pressure-sensitive adhesive layer (B), the release surface of the acrylic pressure-sensitive adhesive layer (B) on the release layer (A2) side can be adjusted to a range of 15 μm to 0.60 μm. The arithmetic average surface roughness Ra2 can be adjusted to a range of 0.15 μm to 0.60 μm, and the initial adhesive force on the surfaces on both sides of the acrylic pressure-sensitive adhesive layer (B) can be appropriately controlled. The fine particles (P) contained in the release layer (A1) and the fine particles (P) contained in the release layer (A2) may be the same kind of fine particles or different kinds of fine particles. Further, the fine particles (P) contained in the release layer (A1) may be only one kind or two or more kinds. Further, the fine particles (P) contained in the release layer (A2) may be only one kind or two or more kinds.

  Examples of such fine particles (P) include calcium carbonate, synthetic zeolite, natural zeolite, aluminum silicate porous ore, synthetic silica, natural silica, acrylic cross-linked particles, styrene cross-linked particles, polymer beads, cross-linked poly Methyl methacrylate, ultra high molecular weight polyethylene, talc, minerals (feldspar, leucite, nepheline, nepheline sianite, fluorite, etc.), hydrous magnesium silicate, these surface treatments, other organic fillers, other inorganic fillers Agents and the like.

  The average particle diameter of the fine particles (P) is 4 μm to 25 μm, preferably 5 μm to 20 μm. By keeping the average particle diameter of the fine particles (P) within the above range, the surfaces on both sides of the acrylic pressure-sensitive adhesive layer (B) are sufficiently roughened, and the surfaces of both sides of the acrylic pressure-sensitive adhesive layer (B) are roughened. It becomes possible to provide an adhesive sheet whose initial adhesive strength can be controlled. If the average particle diameter of the fine particles (P) is too small, the surfaces on both sides of the acrylic pressure-sensitive adhesive layer (B) may not be sufficiently roughened. If the average particle size of the fine particles (P) is too large, for example, it may be difficult to obtain the pressure-sensitive adhesive sheet of the present invention integrally by coextrusion molding. The average particle size is a volume-based cumulative 50% particle size (D50) obtained from the particle size distribution measured by the laser diffraction scattering method.

  The content ratio of the fine particles (P) in the release layer (A1) is 0.1 wt% to 20 wt%, preferably 1.0 wt% to 19 wt%, more preferably 3.0 wt% to 18% by weight. By keeping the content ratio of the fine particles (P) in the release layer (A1) within the above range, the surface of the acrylic pressure-sensitive adhesive layer (B) on the release layer (A1) side is sufficiently roughened, and the acrylic type It is possible to provide a pressure-sensitive adhesive sheet in which the initial pressure-sensitive adhesive force on the surface of the pressure-sensitive adhesive layer (B) on the release layer (A1) side can be controlled. If the content ratio of the fine particles (P) in the release layer (A1) is too small, the surface of the acrylic pressure-sensitive adhesive layer (B) on the release layer (A1) side may not be sufficiently roughened. When there are too many content rates in the peeling layer (A1) of microparticles | fine-particles (P), there exists a possibility that it may become difficult to obtain the adhesive sheet of this invention by integrating by coextrusion molding, for example.

  The content ratio of the fine particles (P) in the release layer (A2) is 0.1 wt% to 20 wt%, preferably 1.0 wt% to 19 wt%, more preferably 3.0 wt% to 18% by weight. By keeping the content ratio of the fine particles (P) in the release layer (A2) within the above range, the surface of the acrylic pressure-sensitive adhesive layer (B) on the side of the release layer (A2) is sufficiently roughened. It is possible to provide a pressure-sensitive adhesive sheet in which the initial pressure-sensitive adhesive force on the surface of the pressure-sensitive adhesive layer (B) on the release layer (A2) side can be controlled. If the content ratio of the fine particles (P) in the release layer (A2) is too small, the surface of the acrylic pressure-sensitive adhesive layer (B) on the release layer (A2) side may not be sufficiently roughened. When there are too many content rates in the peeling layer (A2) of microparticles | fine-particles (P), there exists a possibility that it may become difficult to obtain the adhesive sheet of this invention integrally by coextrusion molding, for example.

<< Another Release Layer (A1 ') and Another Release Layer (A2') >>
For example, as shown in FIG. 2, the pressure-sensitive adhesive sheet of the present invention may have another release layer (A1 ′) on the opposite side of the release layer (A1) from the acrylic pressure-sensitive adhesive layer (B). This another release layer (A1 ′) may be only one layer or two or more layers. Moreover, for example, as shown in FIG. 3, the pressure-sensitive adhesive sheet of the present invention may have another release layer (A2 ′) on the opposite side of the release layer (A2) from the acrylic pressure-sensitive adhesive layer (B). good. This another release layer (A2 ′) may be only one layer or two or more layers.

  The material, composition, characteristics and the like of the separate release layer (A1 ′) and the separate release layer (A2 ′) are the fine particles (P) contained in the release layer (A1) and the release layer (A2), respectively. Except for not containing, the above description of the release layer (A1) and release layer (A2) can be used as they are.

≪Acrylic adhesive layer (B) ≫
The acrylic pressure-sensitive adhesive layer (B) is laminated with the release layer (A1) and the release layer (A2).

  The thickness of the acrylic pressure-sensitive adhesive layer (B) can be set to any appropriate thickness depending on the application. The thickness of the acrylic pressure-sensitive adhesive layer (B) is preferably 1 μm to 200 μm, more preferably 2 μm to 100 μm, and further preferably 3 μm to 50 μm. If the thickness of the acrylic pressure-sensitive adhesive layer (B) is too thin, the surface of the acrylic pressure-sensitive adhesive layer (B) may not be sufficiently roughened. If the thickness of the acrylic pressure-sensitive adhesive layer (B) is too thick, for example, it may be difficult to obtain the pressure-sensitive adhesive sheet of the present invention integrally by coextrusion molding.

  The acrylic pressure-sensitive adhesive layer (B) may consist of only one layer or may consist of two or more layers. When the acrylic pressure-sensitive adhesive layer (B) is composed of only one layer, coextrusion molding can be facilitated. When the acrylic pressure-sensitive adhesive layer (B) is composed of two or more layers, the function can be divided by each layer.

  The pressure-sensitive adhesive contained in the acrylic pressure-sensitive adhesive layer (B) is preferably an acrylic type containing an acrylate block structure (referred to as “Ac block”) and a methacrylate block structure (referred to as “MAc block”). A block copolymer is mentioned. The acrylic pressure-sensitive adhesive layer (B) more preferably contains 50 wt% or more of such an acrylic block copolymer, more preferably 70 wt% or more, and particularly preferably 90 wt% or more. The acrylic pressure-sensitive adhesive layer (B) may contain only one kind of such an acrylic block copolymer, or may contain two or more kinds.

  The acrylic block copolymer preferably has a block structure in which Ac blocks and MAc blocks are alternately arranged. Further, the total number of blocks of the Ac block and the MAc block is preferably 3 or more, and more preferably 3 to 5.

  The Ac block preferably has a block structure derived from a monomer mainly composed of an acrylate ester. Specifically, the content of the acrylic acid ester in the monomer for constituting the Ac block is preferably 50% by weight or more, more preferably 70% by weight or more, and further preferably 90% by weight or more. Particularly preferably 95% by weight or more, and most preferably substantially 100% by weight.

  The acrylic ester in the monomer for constituting the Ac block may be only one kind or two or more kinds.

  When the monomer for constituting the Ac block includes a monomer (another monomer) other than the acrylate ester, any appropriate monomer can be adopted as the other monomer.

  Examples of the acrylic acid ester in the monomer for constituting the Ac block include an aliphatic hydrocarbon ester of acrylic acid, an alicyclic hydrocarbon ester of acrylic acid, an aromatic hydrocarbon ester of acrylic acid, and an ether bond. Examples include esters of alcohol and acrylic acid, acrylic esters having a hydroxyl group, acrylic esters having an amino group, acrylic esters having an alkoxysilyl group, and alkylene oxide adducts of acrylic acid.

  Examples of the aliphatic hydrocarbon ester of acrylic acid include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, n-pentyl acrylate, n-hexyl acrylate, Examples thereof include n-heptyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, isononyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate and the like.

  Examples of the alicyclic hydrocarbon ester of acrylic acid include cyclohexyl acrylate and isobornyl acrylate.

  Examples of the aromatic hydrocarbon ester of acrylic acid include phenyl acrylate, benzyl acrylate, toluyl acrylate, and the like.

  Examples of the ester of an alcohol containing an ether bond and acrylic acid include alkoxyalkyl acrylates such as 2-methoxyethyl acrylate and 2-methoxybutyl acrylate; epoxy group-containing acrylates such as glycidyl acrylate and methyl glycidyl acrylate; .

  Examples of the acrylic acid ester having a hydroxyl group include hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, and 4-hydroxybutyl acrylate.

  Examples of the acrylic acid ester having an amino group include 2-aminoethyl acrylate, N, N-dimethylaminoethyl acrylate, N, N-dimethylaminopropyl acrylate, and the like.

  Examples of the acrylic acid ester having an alkoxysilyl group include 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-acryloxypropylmethyldimethoxysilane, and 3-acryloxypropylmethyldiethoxysilane. Is mentioned.

Examples of the alkylene oxide adduct of acrylic acid include an ethylene oxide adduct represented by CH ₂ ═CHCOO (CH ₂ CH ₂ O) _n H (n is, for example, 1 to 10).

  The acrylic ester in the monomer for constituting the Ac block is preferably an aliphatic hydrocarbon ester of acrylic acid. The acrylic ester in the monomer for constituting the Ac block is more preferably an alkyl acrylate having an alkyl group having 1 to 20 carbon atoms, and still more preferably having 1 to 14 carbon atoms. Acrylic acid alkyl ester having an alkyl group. As the acrylic acid ester in the monomer for constituting the Ac block, methyl acrylate, n-butyl acrylate, tert-butyl acrylate, and 2-ethylhexyl acrylate are particularly preferable.

  The MAc block is preferably a block structure derived from a monomer mainly composed of a methacrylic ester. Specifically, the content ratio of the methacrylic acid ester in the monomer for constituting the MAc block is preferably 50% by weight or more, more preferably 70% by weight or more, and further preferably 90% by weight or more. Particularly preferably 95% by weight or more, and most preferably substantially 100% by weight.

  The methacrylic acid ester in the monomer for constituting the MAc block may be only one kind or two or more kinds.

  When the monomer for constituting the MAc block contains a monomer other than the methacrylic acid ester (other monomer), any appropriate monomer can be adopted as the other monomer.

  Examples of the methacrylic acid ester in the monomer constituting the MAc block include, for example, an aliphatic hydrocarbon ester of methacrylic acid, an alicyclic hydrocarbon ester of methacrylic acid, an aromatic hydrocarbon ester of methacrylic acid, and an ether bond. Examples include esters of alcohol and methacrylic acid, methacrylates having a hydroxyl group, methacrylates having an amino group, methacrylates having an alkoxysilyl group, and alkylene oxide adducts of methacrylic acid.

  Examples of the aliphatic hydrocarbon esters of methacrylic acid include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, tert-butyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, Examples include n-heptyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, isononyl methacrylate, decyl methacrylate, dodecyl methacrylate, stearyl methacrylate and the like.

  Examples of alicyclic hydrocarbon esters of methacrylic acid include cyclohexyl methacrylate and isobornyl methacrylate.

  Examples of the aromatic hydrocarbon ester of methacrylic acid include phenyl methacrylate, benzyl methacrylate, toluyl methacrylate and the like.

  Examples of the ester of alcohol containing an ether bond and methacrylic acid include alkoxyalkyl methacrylates such as 2-methoxyethyl methacrylate and 2-methoxybutyl methacrylate; epoxy group-containing methacrylates such as glycidyl methacrylate and methyl glycidyl methacrylate; .

  Examples of the methacrylic acid ester having a hydroxyl group include hydroxyalkyl methacrylates such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl methacrylate, and 4-hydroxybutyl methacrylate.

  Examples of the methacrylic acid ester having an amino group include 2-aminoethyl methacrylate, N, N-dimethylaminoethyl methacrylate, N, N-dimethylaminopropyl methacrylate and the like.

  Examples of the methacrylic acid ester having an alkoxysilyl group include 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-methacryloxypropylmethyldiethoxysilane. Is mentioned.

Examples of the alkylene oxide adduct of methacrylic acid include an ethylene oxide adduct represented by CH ₂ ═C (CH ₃ ) COO (CH ₂ CH ₂ O) _n H (n is, for example, 1 to 10). Can be mentioned.

  The methacrylic acid ester in the monomer for constituting the MAc block is preferably an aliphatic hydrocarbon ester of methacrylic acid. The methacrylic acid ester in the monomer for constituting the MAc block is more preferably a methacrylic acid alkyl ester having an alkyl group having 1 to 20 carbon atoms, more preferably 1 to 14 carbon atoms. It is a methacrylic acid alkyl ester having an alkyl group. As the methacrylic acid ester in the monomer for constituting the MAc block, methyl methacrylate and ethyl methacrylate are particularly preferable.

  As an acrylic block copolymer, the Ac block and the MAc block are composed of a polymer having a hard structure excellent in cohesion and elasticity such as AB type, ABA type, ABAB type, and ABABA type. The segment) and the B block (soft segment) made of a polymer having a soft structure excellent in viscosity preferably have a block structure in which they are alternately arranged. The acrylic pressure-sensitive adhesive layer (B) containing the acrylic block copolymer having such a structure as a main component can be a pressure-sensitive adhesive layer in which cohesive force, elasticity and viscosity are highly compatible. Further, the acrylic pressure-sensitive adhesive layer (B) containing the acrylic block copolymer having such a structure as a main component can be excellent in extrusion moldability. The acrylic block copolymer preferably has a block structure (ABA type, ABABA type, etc.) in which A blocks (hard segments) are arranged at both ends of the molecule. The acrylic block copolymer having such a block structure can be excellent in balance between cohesiveness and thermoplasticity.

  When the acrylic block copolymer has two or more A blocks (hard segments), the monomer composition, molecular weight (degree of polymerization), structure, etc. of these A blocks may be the same or different from each other. Also good.

  When the acrylic block copolymer has two or more B blocks (soft segments), the monomer composition, molecular weight (degree of polymerization), structure, etc. of these B blocks may be the same or different from each other. Also good.

  As the A block (hard segment), a MAc block can be preferably used. As the B block (soft segment), an Ac block can be preferably used.

  A preferred form of the block structure of the acrylic block copolymer is, for example, a triblock structure of MAc block / Ac block / MAc block (ABA type) structure. A more preferable form of the block structure of the acrylic block copolymer is one in which the two MAc blocks have a structure derived from substantially the same monomer in the above triblock structure.

  The ratio of Ac block to MAc block contained in the acrylic block copolymer is a weight ratio, and the weight ratio of Ac block / MAc block is preferably 96/4 to 10/90, more preferably 93 / It is 7-20 / 80, More preferably, it is 90 / 10-30 / 70, Especially preferably, it is 85 / 15-40 / 60, Most preferably, it is 80 / 20-50 / 50. If the proportion of the Ac block is too large, the cohesive force and elasticity may be insufficient. If the proportion of the MAc block is too large, the adhesive strength may be insufficient.

  In the acrylic pressure-sensitive adhesive layer (B), the weight ratio of the Ac block / MAc block is preferably 96/4 to 50/50, more preferably 93/7, in order to develop the adhesive force as much as possible. It is -60/40, More preferably, it is 90 / 10-65 / 35, Especially preferably, it is 80 / 20-70 / 30.

  The weight average molecular weight of the acrylic block copolymer is preferably 30000 to 300000, more preferably 35000 to 250,000, still more preferably 40000 to 200000, and particularly preferably 50000 to 150,000. When the weight average molecular weight of the acrylic block copolymer is less than 30000, there is a possibility that the adhesive properties and cohesiveness are likely to be lowered. If the weight average molecular weight of the acrylic block copolymer exceeds 300,000, the acrylic block copolymer is insufficient in thermoplasticity, and it may be difficult to form the acrylic pressure-sensitive adhesive layer (B) by coextrusion molding. There is.

  The weight average molecular weight of the acrylic block copolymer can be determined by performing gel permeation chromatography (GPC) measurement on a sample prepared by dissolving the acrylic block copolymer in an appropriate solvent such as tetrahydrofuran. The value in terms of polystyrene. Specifically, the weight average molecular weight of the acrylic block copolymer can be determined by performing GPC measurement under the conditions described in the examples described later.

  The glass transition temperature (Tg) of the Ac block is preferably −80 ° C. to −10 ° C., more preferably −75 ° C. to −20 ° C., and further preferably −75 ° C. to −50 ° C.

  The glass transition temperature (Tg) of the MAc block is preferably 40 ° C to 240 ° C, more preferably 60 ° C to 230 ° C, and still more preferably 80 ° C to 230 ° C.

  Here, the glass transition temperature (Tg) of the Ac block or the MAc block is the fox based on the Tg of the homopolymer of each monomer constituting the block and the content ratio (weight fraction) of the monomer. A value obtained from the formula (FOX). As the Tg of the homopolymer, for example, the values described in “Adhesion Technology Handbook” of Nikkan Kogyo Shimbun and “Polymer Handbook” of Wiley-Interscience can be adopted. For example, Tg of 2-ethylhexyl acrylate can be -70 ° C, Tg of n-butyl acrylate can be -54 ° C, and Tg of methyl methacrylate can be 105 ° C.

  Arbitrary appropriate other monomers other than acrylic acid ester and methacrylic acid ester may be copolymerized with the acrylic block copolymer. Examples of such other monomers include cyano group-containing vinyl compounds such as acrylonitrile and methacrylonitrile; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and α-methylstyrene; N— Vinyl group-containing heterocyclic compounds such as vinyl pyrrolidone; Amide group-containing vinyl compounds such as acrylamide and methacrylamide; Unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid or salts thereof (sodium salt, potassium salt, etc.); maleic acid, Unsaturated dicarboxylic acids such as fumaric acid or salts thereof (sodium salt, potassium salt, etc.); unsaturated dicarboxylic acid anhydrides such as maleic anhydride; methyl 2- (trifluoromethyl) (meth) acrylate, methyl 2- (par Fluoroethyl) (meth) acrylate, ethyl 2- (trifluoromethyl) (meth) acrylate, ethyl 2- (perfluoroethyl) (meth) acrylate, ethyl 2- (perfluorohexyl) (meth) acrylate, ethyl 2- (perfluorodecyl) (meth) acrylate And fluorinated alkyl (meth) acrylates such as ethyl 2- (perfluorohexadecyl) (meth) acrylate and ethyl 2- (perfluorobutyl) (meth) acrylate. Such other monomers may be only one kind or two or more kinds.

  Other monomers may be included, for example, to adjust the characteristics (such as adhesive characteristics and extrusion moldability) of the acrylic pressure-sensitive adhesive layer (B). Other structural parts derived from monomers can be introduced into the Ac block or MAc block in the form of a random copolymer, block copolymer, graft copolymer or the like.

  In the monomer for constituting the acrylic block copolymer, the content of other monomers is preferably 20% by weight or less, more preferably 10% by weight in the monomer for constituting the acrylic block copolymer. % Or less, more preferably 5% by weight or less, and particularly preferably substantially 0% by weight. In the monomer for constituting the acrylic block copolymer, if the content of other monomers is too large, the transparency of the acrylic pressure-sensitive adhesive layer (B) may be impaired.

  In particular, the acrylic block copolymer preferably does not substantially contain an acid group-containing monomer as another monomer in the monomer constituting the acrylic block copolymer. The acrylic pressure-sensitive adhesive layer (B) containing such an acrylic block copolymer can have a lower property of corroding the adherend. For example, in a pressure-sensitive adhesive sheet for use in bonding an adherend having a transparent electrode such as ITO (Indium Tin Oxide) (for example, a component of a touch panel), the adherend corrosivity of the pressure-sensitive adhesive layer is low. Especially preferred. In addition, an acrylic block copolymer composed of a monomer that does not substantially contain an acidic group-containing monomer as a monomer is preferable in that it can avoid the melt viscosity of the pressure-sensitive adhesive layer from becoming too high.

  The acrylic block copolymer can be produced by any appropriate method. As a manufacturing method of an acryl-type block copolymer, the manufacturing method using a living polymerization method etc. are mentioned, for example. According to the living polymerization method, the acrylic block copolymer has excellent thermoplasticity and good extrudability by maintaining the original transparency and weather resistance of the acrylic block copolymer, and by excellent structural control unique to the living polymerization method. Copolymers can be produced. In addition, the living polymerization method can control the molecular weight distribution of the acrylic block copolymer narrowly, thereby suppressing a decrease in cohesiveness due to the presence of low molecular weight components (for example, adhesive residue at the time of peeling). Thus, a pressure-sensitive adhesive sheet having excellent peelability can be provided.

  The acrylic block copolymer can also be obtained as a commercial product. Examples of the acrylic block copolymer available as a commercially available product include a trade name “KURRITY” series (for example, LA410L, LA2140e, LA2250, LA4285, LA2330, etc.) manufactured by Kuraray Co., Ltd.

  The acrylic pressure-sensitive adhesive layer (B) can contain an optional component other than the acrylic block copolymer for the purpose of controlling the adhesive properties. Examples of such an optional component include polymers other than acrylic block copolymers and called oligomers (having a weight average molecular weight of, for example, 500 to 5000). Examples of such oligomers include random copolymers of monomers mainly composed of acrylic monomers (such as acrylic acid esters and methacrylic acid esters), and have no block structure, olefinic resins, silicones. System polymers and the like. Moreover, in order not to impair the transparency of the acrylic pressure-sensitive adhesive layer (B), it is preferable to select a polymer excellent in compatibility with the acrylic block copolymer. There may be only one optional component, or two or more optional components.

  The content of the optional component is preferably 50 parts by weight or less, more preferably 10 parts by weight or less, still more preferably 5 parts by weight or less, with respect to 100 parts by weight of the acrylic block copolymer. Preferably it is substantially 0 part by weight.

  The acrylic pressure-sensitive adhesive layer (B) can contain any appropriate other component as required. Examples of other components include tackifiers, fillers, colorants (dyes, etc.), antioxidants, metal chelate compounds, cross-linking agents (eg, polyfunctional isocyanates, polyfunctional amines, polyfunctional alcohols, etc.) Is mentioned. The kind, number, and amount of other components that can be contained in the acrylic pressure-sensitive adhesive layer (B) can be appropriately set depending on the purpose. From the viewpoint of taking advantage of the transparency of the acrylic block copolymer, the amount of other components is preferably 5% by weight or less, more preferably 1% by weight based on the entire acrylic pressure-sensitive adhesive layer (B). % Or less.

  The tackifier is effective for improving the adhesive strength. In the case where the acrylic pressure-sensitive adhesive layer (B) contains a tackifier, the content ratio of the tackifier in the acrylic pressure-sensitive adhesive layer (B) takes into consideration prevention of occurrence of adhesive residue due to a decrease in cohesive force, Any appropriate content ratio can be set. The content ratio of the tackifier in the acrylic pressure-sensitive adhesive layer (B) is preferably 1% by weight to 60% by weight and more preferably 3% by weight with respect to the whole acrylic pressure-sensitive adhesive layer (B). -50% by weight, more preferably 4% by weight to 45% by weight, and particularly preferably 5% by weight to 40% by weight.

  Examples of tackifiers include hydrocarbon tackifiers, terpene tackifiers, rosin tackifiers, phenol tackifiers, epoxy tackifiers, polyamide tackifiers, and elastomer tackifiers. And ketone-based tackifiers. Only 1 type may be sufficient as the tackifier in a 1st adhesive layer (B1), and 2 or more types may be sufficient as it.

  Examples of the hydrocarbon tackifier include aliphatic hydrocarbon resins, aromatic hydrocarbon resins (for example, xylene resins), aliphatic cyclic hydrocarbon resins, aliphatic / aromatic petroleum resins (for example, Styrene-olefin copolymers, aliphatic / alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, coumarone-indene resins, and the like.

  Examples of the terpene tackifier include terpene resins such as α-pinene polymers and β-pinene polymers; modified terpenes obtained by modifying terpene resins (for example, phenol modification, aromatic modification, hydrogenation modification, etc.) Resin (for example, terpene-phenol resin, styrene-modified terpene resin, hydrogenated terpene resin, etc.);

  Examples of rosin-based tackifiers include unmodified rosins such as gum rosin and wood rosin (raw rosin); modified rosins modified by hydrogenation, disproportionation, polymerization, etc. (for example, hydrogenated rosin, Averaged rosin, polymerized rosin, other chemically modified rosins, etc.); various other rosin derivatives;

  Examples of the phenol tackifier include resol type or novolac type alkylphenols.

  The tackifier may be commercially available as a blend with an olefin resin or a thermoplastic elastomer.

  Examples of the filler include inorganic fillers such as talc, titanium oxide, calcium oxide, magnesium oxide, zinc oxide, titanium oxide, calcium carbonate, silica, clay, mica, barium sulfate, whisker, and magnesium hydroxide. The average particle diameter of the filler is preferably 0.1 μm to 10 μm.

  The kind, number, and amount of other components that can be contained in the acrylic pressure-sensitive adhesive layer (B) can be appropriately set depending on the purpose. From the viewpoint of taking advantage of the transparency of the acrylic block copolymer, the amount of other components is preferably 5% by weight or less, more preferably 1% by weight based on the entire acrylic pressure-sensitive adhesive layer (B). % Or less.

≪Base material layer (C) ≫
The pressure-sensitive adhesive sheet of the present invention comprises an acrylic pressure-sensitive adhesive layer (B), a release layer (A1) provided on one side of the acrylic pressure-sensitive adhesive layer (B), and the other of the acrylic pressure-sensitive adhesive layer (B). If it has the peeling layer (A2) provided on one side, the base material layer (C) may be provided at any appropriate position within a range not impairing the effects of the present invention. Only one layer may be sufficient as a base material layer (C), and two or more layers may be sufficient as it.

  The thickness of the base material layer (C) can be set to any appropriate thickness depending on the application. The thickness of the base material layer (C) is preferably 1 μm to 200 μm, more preferably 2 μm to 100 μm, and further preferably 3 μm to 80 μm. When the thickness of the base material layer (C) is too thin, the purpose for providing the base material layer (C) may not be achieved. If the thickness of the base material layer (C) is too thick, for example, it may be difficult to obtain the pressure-sensitive adhesive sheet of the present invention integrally by coextrusion molding.

  The base material layer (C) preferably contains an acrylic resin. The base material layer (C) more preferably contains 50% by weight or more of such an acrylic resin, more preferably 70% by weight or more, and particularly preferably 90% by weight or more. The base material layer (C) may contain only one kind of such an acrylic resin, or may contain two or more kinds. When the base material layer (C) contains an acrylic resin, it can be effectively integrated with the acrylic pressure-sensitive adhesive layer (B) when the pressure-sensitive adhesive sheet of the present invention is obtained by coextrusion molding.

  As an acrylic resin that can be contained in the base material layer (C), any appropriate acrylic resin can be adopted as long as it is generally referred to as an acrylic resin, as long as the effects of the present invention are not impaired. . Examples of such acrylic resins include homopolymers of acrylic monomers, copolymers of two or more acrylic monomers, and the like.

  The acrylic resin that can be contained in the base material layer (C) is preferably an acrylic resin containing an acrylate block structure (referred to as “Ac block”) and a methacrylic ester block structure (referred to as “MAc block”). A block copolymer is mentioned. The acrylic base layer (C) may contain only one kind of such an acrylic block copolymer, or may contain two or more kinds.

  The acrylic block copolymer preferably has a block structure in which Ac blocks and MAc blocks are alternately arranged. Further, the total number of blocks of the Ac block and the MAc block is preferably 3 or more, and more preferably 3 to 5.

  The Ac block preferably has a block structure derived from a monomer mainly composed of an acrylate ester. Specifically, the content of the acrylic acid ester in the monomer for constituting the Ac block is preferably 50% by weight or more, more preferably 70% by weight or more, and further preferably 90% by weight or more. Particularly preferably 95% by weight or more, and most preferably substantially 100% by weight.

  The acrylic ester in the monomer for constituting the Ac block may be only one kind or two or more kinds.

  When the monomer for constituting the Ac block includes a monomer (another monomer) other than the acrylate ester, any appropriate monomer can be adopted as the other monomer.

  The acrylic ester in the monomer for constituting the Ac block is the same as that described in the section of << Acrylic pressure-sensitive adhesive layer (B) >>.

  The MAc block is preferably a block structure derived from a monomer mainly composed of a methacrylic ester. Specifically, the content ratio of the methacrylic acid ester in the monomer for constituting the MAc block is preferably 50% by weight or more, more preferably 70% by weight or more, and further preferably 90% by weight or more. Particularly preferably 95% by weight or more, and most preferably substantially 100% by weight.

  The methacrylic acid ester in the monomer for constituting the MAc block may be only one kind or two or more kinds.

  When the monomer for constituting the MAc block contains a monomer other than the methacrylic acid ester (other monomer), any appropriate monomer can be adopted as the other monomer.

  The methacrylic acid ester in the monomer for constituting the MAc block is the same as that described in the section of << Acrylic pressure-sensitive adhesive layer (B) >>.

  As an acrylic block copolymer, the Ac block and the MAc block are composed of a polymer having a hard structure excellent in cohesion and elasticity such as AB type, ABA type, ABAB type, and ABABA type. The segment) and the B block (soft segment) made of a polymer having a soft structure excellent in viscosity preferably have a block structure in which they are alternately arranged. The base material layer (C) containing the acrylic block copolymer having such a structure as a main component can be a base material layer in which cohesive force, elasticity and viscosity are highly compatible. Moreover, the base material layer (C) containing the acrylic block copolymer having such a structure as a main component can be excellent in extrusion moldability. The acrylic block copolymer preferably has a block structure (ABA type, ABABA type, etc.) in which A blocks (hard segments) are arranged at both ends of the molecule. The acrylic block copolymer having such a block structure can be excellent in balance between cohesiveness and thermoplasticity.

  When the acrylic block copolymer has two or more A blocks (hard segments), the monomer composition, molecular weight (degree of polymerization), structure, etc. of these A blocks may be the same or different from each other. Also good.

  When the acrylic block copolymer has two or more B blocks (soft segments), the monomer composition, molecular weight (degree of polymerization), structure, etc. of these B blocks may be the same or different from each other. Also good.

  As the A block (hard segment), a MAc block can be preferably used. As the B block (soft segment), an Ac block can be preferably used.

  A preferred form of the block structure of the acrylic block copolymer is, for example, a triblock structure of MAc block / Ac block / MAc block (ABA type) structure. A more preferable form of the block structure of the acrylic block copolymer is one in which the two MAc blocks have a structure derived from substantially the same monomer in the above triblock structure.

  The ratio of Ac block to MAc block contained in the acrylic block copolymer is a weight ratio, and the weight ratio of Ac block / MAc block is preferably 96/4 to 10/90, more preferably 93 / It is 7-20 / 80, More preferably, it is 90 / 10-30 / 70, Especially preferably, it is 85 / 15-40 / 60, Most preferably, it is 80 / 20-50 / 50. If the proportion of the Ac block is too large, the cohesive force and elasticity may be insufficient. If the proportion of the MAc block is too large, the adhesive strength may be insufficient.

  In the base material layer (C), the function as the base material layer is sufficiently developed. For example, the release layer (A1), the release layer (A2), another release layer (A1 ′), or another release layer. In order to allow easy delamination with (A2 ′), the weight ratio of the Ac block / MAc block is preferably 80/20 to 10/90, more preferably 75/25 to 25/25. 20/80, more preferably 70/30 to 30/70, particularly preferably 65/35 to 35/65, and most preferably 60/40 to 40/60.

  The weight average molecular weight of the acrylic block copolymer is preferably 30000 to 300000, more preferably 35000 to 250,000, still more preferably 40000 to 200000, and particularly preferably 50000 to 150,000. When the weight average molecular weight of the acrylic block copolymer is less than 30000, there is a possibility that the adhesive properties and cohesiveness are likely to be lowered. When the weight average molecular weight of the acrylic block copolymer exceeds 300,000, the acrylic block copolymer is insufficient in thermoplasticity, and it may be difficult to form the base material layer (C) by coextrusion molding. .

  The weight average molecular weight of the acrylic block copolymer can be determined by performing gel permeation chromatography (GPC) measurement on a sample prepared by dissolving the acrylic block copolymer in an appropriate solvent such as tetrahydrofuran. The value in terms of polystyrene. Specifically, the weight average molecular weight of the acrylic block copolymer can be determined by performing GPC measurement under the conditions described in the examples described later.

  The glass transition temperature (Tg) of the Ac block and the glass transition temperature (Tg) of the MAc block are the same as those described in the section << Acrylic pressure-sensitive adhesive layer (B) >>.

  Arbitrary appropriate other monomers other than acrylic acid ester and methacrylic acid ester may be copolymerized with the acrylic block copolymer. Such other monomers are the same as those described in the section of << Acrylic pressure-sensitive adhesive layer (B) >>.

  In the monomer for constituting the acrylic block copolymer, the content of other monomers is preferably 20% by weight or less, more preferably 10% by weight in the monomer for constituting the acrylic block copolymer. % Or less, more preferably 5% by weight or less, and particularly preferably substantially 0% by weight. In the monomer for constituting the acrylic block copolymer, if the content of other monomers is too large, the transparency of the base material layer (C) may be impaired.

  In particular, the acrylic block copolymer preferably does not substantially contain an acid group-containing monomer as another monomer in the monomer constituting the acrylic block copolymer. The base material layer (C) containing such an acrylic block copolymer can have a lower property of corroding the adherend.

  The acrylic block copolymer can be produced by any appropriate method. About such a manufacturing method, it is the same as that of what was demonstrated in the term of << acrylic adhesive layer (B) >>.

  The acrylic block copolymer can also be obtained as a commercial product. Examples of the acrylic block copolymer available as a commercially available product include a trade name “KURRITY” series (for example, LA410L, LA2140e, LA2250, LA4285, LA2330, etc.) manufactured by Kuraray Co., Ltd.

  The base material layer (C) can contain an optional component other than the acrylic block copolymer. Examples of such an optional component include polymers other than acrylic block copolymers and called oligomers (having a weight average molecular weight of, for example, 500 to 5000). Examples of such oligomers include random copolymers of monomers mainly composed of acrylic monomers (such as acrylic acid esters and methacrylic acid esters), and have no block structure, olefinic resins, silicones. System polymers and the like. Moreover, in order not to impair the transparency of the base material layer (C), it is preferable to select a polymer excellent in compatibility with the acrylic block copolymer. There may be only one optional component, or two or more optional components.

  The content of the optional component is preferably 50 parts by weight or less, more preferably 10 parts by weight or less, still more preferably 5 parts by weight or less, with respect to 100 parts by weight of the acrylic block copolymer. Preferably it is substantially 0 part by weight.

  A base material layer (C) may contain arbitrary appropriate other components as needed. Such other components are the same as those described in the section of «Acrylic pressure-sensitive adhesive layer (B)».

  The kind, number, and amount of other components that can be contained in the base material layer (C) can be appropriately set depending on the purpose. From the viewpoint of utilizing the transparency of the acrylic block copolymer, the amount of the other component is preferably 5% by weight or less, more preferably 1% by weight or less, based on the entire base material layer (C). It is.

≪≪Method for producing adhesive sheet≫≫
The pressure-sensitive adhesive sheet of the present invention is preferably integrated by coextrusion molding.

  The pressure-sensitive adhesive sheet of the present invention comprises an acrylic pressure-sensitive adhesive layer (B) forming material (b), a peeling layer (A1) forming material (a1), a peeling layer (A2) forming material (a2), and if necessary. Then, the forming material (a1 ′) of the release layer (A1 ′), the forming material (a2 ′) of the release layer (A2 ′), and the forming material (c) of the base layer (C) are at least acrylic adhesive. The release layer (A1) and release layer (A2) can be obtained by coextrusion molding and integration so that the release layer (A1) and release layer (A2) are directly laminated on the surface sides on both sides of the agent layer (B).

  For example, as shown in FIG. 1, the pressure-sensitive adhesive sheet of the present invention comprises an acrylic pressure-sensitive adhesive layer (B), a release layer (A1) provided on one side of the acrylic pressure-sensitive adhesive layer (B), and the acrylic sheet. When the adhesive sheet of the present invention comprises a release layer (A2) provided on the other side of the adhesive layer (B), the adhesive sheet of the present invention is peeled from the forming material (b) of the acrylic adhesive layer (B). The forming material (a1) of the layer (A1) and the forming material (a2) of the release layer (A2) are separated from each other on the surfaces of both sides of the acrylic pressure-sensitive adhesive layer (B) by the release layer (A1) and the release layer (A2). They can be obtained by coextrusion and integration so that they are laminated directly.

  For example, as the pressure-sensitive adhesive sheet of the present invention is shown in FIG. 2, the acrylic pressure-sensitive adhesive layer (B), the release layer (A1) provided on one side of the acrylic pressure-sensitive adhesive layer (B), and the acrylic type A release layer (A2) provided on the other side of the pressure-sensitive adhesive layer (B) and another release layer provided on the opposite side of the release layer (A1) from the acrylic pressure-sensitive adhesive layer (B) ( A1 ′), the pressure-sensitive adhesive sheet of the present invention forms the acrylic pressure-sensitive adhesive layer (B) forming material (b), the peeling layer (A1) forming material (a1), and the peeling layer (A2). The material (a2) and the material (a1 ′) for forming another release layer (A1 ′) are directly applied to the surfaces on both sides of the acrylic pressure-sensitive adhesive layer (B). And another release layer (A1 ′) directly on the opposite side of the release layer (A1) from the acrylic pressure-sensitive adhesive layer (B). As layers, it can be obtained by integrally coextruded.

  For example, as the pressure-sensitive adhesive sheet of the present invention is shown in FIG. 3, an acrylic pressure-sensitive adhesive layer (B), a release layer (A1) provided on one side of the acrylic pressure-sensitive adhesive layer (B), and the acrylic type A release layer (A2) provided on the other side of the pressure-sensitive adhesive layer (B) and another release layer provided on the opposite side of the release layer (A1) from the acrylic pressure-sensitive adhesive layer (B) ( A1 ′) and another release layer (A2 ′) provided on the opposite side of the acrylic pressure-sensitive adhesive layer (B) of the release layer (A2), Forming layer (A1 ′) forming material (a1 ′), forming layer (A1) forming material (a1), acrylic pressure-sensitive adhesive layer (B) forming material (b) and releasing layer (A2) forming material (A2) and another release layer (A2 ′) forming material (a2 ′) are applied to the surfaces of both sides of the acrylic pressure-sensitive adhesive layer (B). ) And the release layer (A2) are directly laminated, and another release layer (A1 ′) is directly laminated on the opposite side of the release layer (A1) from the acrylic pressure-sensitive adhesive layer (B). It can be obtained by coextrusion molding and integration so that another release layer (A2 ′) is directly laminated on the side of the layer (A2) opposite to the acrylic pressure-sensitive adhesive layer (B).

  As the forming material (a1) of the release layer (A1) and the forming material (a2) of the release layer (A2), the release layer (A1) and the release layer (A1) described in the section of << Release layer (A1) and release layer (A2) >> Any appropriate material can be adopted as long as the release layer (A2) can be formed by coextrusion. Each of the forming material (a1) and the forming material (a2) preferably includes the polyolefin resin and the fine particles (P) described in the section of the << release layer (A1) and release layer (A2) >>. Composition (a). This composition (a) may contain the additive described in the section of << peeling layer (A1) and peeling layer (A2) >> as necessary.

  As a forming material (a1 ′) of another release layer (A1 ′) and a forming material (a2 ′) of another release layer (A2 ′), << another release layer (A1 ′) and another release layer (A2) Any appropriate material can be adopted as long as it is a material that can form another release layer (A1 ′) and another release layer (A2 ′) described in the section “) >> by coextrusion. Such a forming material (a1 ′) and a forming material (a2 ′) are preferably polyolefin-based materials described in the section of << another release layer (A1 ') and another release layer (A2') >>, respectively. It is a composition (a ′) containing a resin. This composition (a ′) may contain the additives described in the section of “Another release layer (A1 ′) and another release layer (A2 ′)” as necessary.

  As the forming material (b) of the acrylic pressure-sensitive adhesive layer (B), the acrylic pressure-sensitive adhesive layer (B) described in the section << Acrylic pressure-sensitive adhesive layer (B) >> can be formed by coextrusion molding. Any appropriate material can be adopted as long as it is a material. Such a forming material (b) is preferably a composition (b) containing the acrylic block copolymer described in the section << Acrylic pressure-sensitive adhesive layer (B) >>. This composition (b) may contain the arbitrary component demonstrated by the term of << acrylic adhesive layer (B) >>, and another component as needed.

  As the forming material (c) of the base material layer (C), any material can be used as long as it can form the base material layer (C) described in the section of <Base material layer (C)> using coextrusion molding. Any suitable material may be employed. Such a forming material (c) is preferably a composition (c) containing the acrylic resin described in the section of << Substrate Layer (C) >>. This composition (c) may contain the arbitrary component demonstrated by the term of << base material layer (C) >> and another component as needed.

  The method of coextrusion molding can employ | adopt arbitrary appropriate methods generally known as coextrusion molding. As such a method, it can carry out according to the inflation method, the T-die method, etc., using an extruder and the die for coextrusion, for example. By this coextrusion molding, the layers are integrated into a laminate.

  You may irradiate an ionizing radiation to the laminated body obtained by integrating by coextrusion molding. Specifically, for example, the obtained laminate may be irradiated with ionizing radiation before being wound in a roll shape or in a state where it is rewound again after being wound in a roll shape. Irradiation with ionizing radiation is preferably performed in an inert gas atmosphere such as nitrogen. Examples of the ionizing radiation include X-rays, γ-rays, ultraviolet rays, visible rays, and electron beams. An electron beam is preferable as the ionizing radiation because of the high generation rate of the reactive species upon irradiation and the deep penetration of the irradiation target. As the electron beam source, various electron beam accelerators such as a Cockloft Walton type, a bandegraft type, a resonant transformer type, an insulating core transformer type, a linear type, a dynamitron type, and a high frequency type can be used. The ionizing radiation may be irradiated from one side of the laminate or from both sides. In terms of simplification of the process, the ionizing radiation is preferably irradiated by ionizing radiation by guiding the laminate to an ionizing radiation irradiating apparatus before winding it into a roll. The irradiation dose of ionizing radiation is preferably 10 kGy to 500 kGy, more preferably 10 kGy to 400 kGy, and even more preferably 10 kGy to 300 kGy, from the viewpoint of improving interlayer adhesion and maintaining physical properties. The acceleration voltage of the ionizing radiation can be appropriately selected according to the type of resin used for the adhesive sheet and the thickness of the adhesive sheet. The acceleration voltage of ionizing radiation is usually preferably in the range of 50 kV to 300 kV. The ionizing radiation may be irradiated once or a plurality of times (preferably twice).

  The pressure-sensitive adhesive sheet of the present invention can be appropriately stretched uniaxially in the longitudinal direction (extrusion direction) or in the width direction (direction orthogonal to the extrusion direction) or biaxially in the longitudinal direction and the width direction. The stretching ratio in the longitudinal direction when stretching is, for example, preferably 1.01 to 10 times, more preferably 1.01 to 5 times, and further preferably 1.01 to 3 times. . The draw ratio in the width direction is, for example, preferably 1.01 to 8 times, more preferably 1.01 to 4 times, and still more preferably 1.01 to 2.5 times. Stretching may be performed in one stage per axis, or may be performed in two or more stages depending on the intended use of the pressure-sensitive adhesive sheet. The stretching temperature at the time of stretching is preferably in the range of (Tg−20 ° C.) to (Tg + 50 ° C.) with respect to the glass transition temperature (Tg) of the resin component constituting the release layer (A) from the viewpoint of stretchability and the like. .

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples at all. In addition, the test and evaluation method in an Example etc. are as follows. Moreover, unless otherwise indicated, a part means a weight part and% means weight%.

<Measurement of weight average molecular weight>
GPC measurement was performed under the following conditions.
Measuring device: Model “HLC-8120GPC” manufactured by Tosoh Corporation
Column: TSKgel SuperHZM-H / HZ4000 + HZ3000 + HZ2000 manufactured by Tosoh Corporation was used in series.
Column size: each 6.0 mm inner diameter x 15.0 cm length
Column temperature: 40 ° C
Flow rate: 0.6 mL / min Eluent: Tetrahydrofuran Sample injection volume: 20 μL
Detector: RI (differential refractometer)
Standard sample: Polystyrene

<Evaluation of arithmetic average surface roughness Ra>
A strip-shaped test piece having a length of 100 mm and a width of 20 mm was cut out from each evaluation sample. At the corner of the test piece, a commercially available adhesive tape (for example, product name “Dumplon Tape No. 375” manufactured by Nitto Denko Corporation) is applied from both sides of the test piece, and then they are pulled apart. The release layer was peeled from the pressure-sensitive adhesive layer from one end of the test piece to a position 30 mm in the longitudinal direction. After sticking the peeled surface of the obtained pressure-sensitive adhesive layer upward on a slide glass, the surface roughness of the peeled surface was measured using a measurement type: VSI (Infinite Scan) using an optical profiler NT9100 (manufactured by Veeco). , Objective: 2.5X, FOV: 1.0X, Modulation Threshold: 0.1%, and measured at n = 3. After the measurement, data analysis was performed using Terms Removal: Tilt Only (Plane Fit) and Window Filtering: None to obtain the arithmetic average surface roughness Ra.

[Example 1]
As a material for forming the release layer (A1), low-density polyethylene (LDPE) (trade name “Petrocene 190” manufactured by Tosoh Corporation) and calcium carbonate (CaCO ₃ ) having an average particle diameter of 8 μm as a fine particle (P) (manufactured by Bihoku Powdered Industries Co., Ltd. , Trade name “BF300”) and an acrylic block copolymer having a pressure-sensitive adhesive function as a material for forming the acrylic pressure-sensitive adhesive layer (B) (made by Kuraray, trade name “KULARITY LA2140e”). ”, Mw = 8.0 × 10 ⁴ ), and low density polyethylene (LDPE) (trade name“ Petrocene 190 ”, manufactured by Tosoh Corporation) as a material for forming the release layer (A2), and having an average particle diameter of 8 μm as fine particles (P) What added 3.5% by weight of calcium carbonate (CaCO ₃ ) (trade name “BF300”, manufactured by Bihoku Flour & Chemical Co., Ltd.) into the extruder, And then extruding to form a laminate of [peeling layer (A1) (thickness = 40 μm)] / [acrylic adhesive layer (B) (thickness = 10 μm)] / [peeling layer (A2) (thickness = 40 μm)]. A pressure-sensitive adhesive sheet (1) having a configuration was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (1) are shown in Table 1.

[Example 2]
Except that the addition amount of the fine particles (P) in the release layer (A1) was 7.0% by weight, the same procedure as in Example 1 was carried out, [Peel layer (A1) (thickness = 40 μm)] / [acrylic adhesive A pressure-sensitive adhesive sheet (2) having a laminated structure of agent layer (B) (thickness = 10 μm) / [peeling layer (A2) (thickness = 40 μm)] was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (2) are shown in Table 1.

Example 3
Except that the addition amount of the fine particles (P) in the release layers (A1) and (A2) was 7.0% by weight, the same procedure as in Example 1 was carried out [Peel layer (A1) (thickness = 40 μm)] / A pressure-sensitive adhesive sheet (3) having a laminated structure of [acrylic pressure-sensitive adhesive layer (B) (thickness = 10 μm)] / [peeling layer (A2) (thickness = 40 μm)] was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (3) are shown in Table 1.

Example 4
Performed in the same manner as in Example 1 except that the addition amount of the fine particles (P) in the release layers (A1) and (A2) was 7.0% by weight, and the thickness of the acrylic pressure-sensitive adhesive layer (B) was 30 μm. , [Peeling layer (A1) (thickness = 40 μm)] / [acrylic pressure-sensitive adhesive layer (B) (thickness = 30 μm)] / [peeling layer (A2) (thickness = 40 μm)] 4) was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (4) are shown in Table 1.

Example 5
The same procedure as in Example 1 was conducted except that the amount of the fine particles (P) in the release layers (A1) and (A2) was 7.0% by weight and the thickness of the release layer (A1) was 80 μm. A pressure-sensitive adhesive sheet (5) having a laminated structure of layer (A1) (thickness = 80 μm)] / [acrylic pressure-sensitive adhesive layer (B) (thickness = 10 μm)] / [peeling layer (A2) (thickness = 40 μm)] Obtained.
The evaluation results for the pressure-sensitive adhesive sheet (5) are shown in Table 1.

Example 6
The amount of the fine particles (P) in the release layers (A1) and (A2) was 7.0% by weight, and block polypropylene (trade name “Novatech PP FL6H” manufactured by Nippon Polypro Co., Ltd.) was used as a material for forming the release layer (A1). )), Except that [Peeling layer (A1) (thickness = 40 μm)] / [Acrylic adhesive layer (B) (thickness = 10 μm)] / [Peeling layer (A2) ) (Thickness = 40 μm)] was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (6) are shown in Table 1.

Example 7
Except that the addition amount of the fine particles (P) in the release layers (A1) and (A2) was 10.5% by weight, it was carried out in the same manner as in Example 1, [Peel layer (A1) (thickness = 40 μm)] / A pressure-sensitive adhesive sheet (7) having a laminated structure of [acrylic pressure-sensitive adhesive layer (B) (thickness = 10 μm)] / [peeling layer (A2) (thickness = 40 μm)] was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (7) are shown in Table 1.

Example 8
Except that the addition amount of the fine particles (P) in the release layers (A1) and (A2) was 17.5% by weight, it was carried out in the same manner as in Example 1, [Peel layer (A1) (thickness = 40 μm)] / A pressure-sensitive adhesive sheet (8) having a laminated structure of [acrylic pressure-sensitive adhesive layer (B) (thickness = 10 μm)] / [peeling layer (A2) (thickness = 40 μm)] was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (8) are shown in Table 1.

[Comparative Example 1]
Low density polyethylene (LDPE) (trade name “Petrocene 190” manufactured by Tosoh Corporation) as a forming material for the release layer (A1) and acrylic block co-polymer having an adhesive function as a forming material for the acrylic pressure sensitive adhesive layer (B) Combined (made by Kuraray, trade name “KULARITY LA2140e”, Mw = 8.0 × 10 ⁴ ), and low density polyethylene (LDPE) (trade name “Petrocene 190” made by Tosoh) as a material for forming the release layer (A2) Was put into an extruder, and melt extrusion was performed from a T-die. [Peeling layer (A1) (thickness = 40 μm)] / [Acrylic pressure-sensitive adhesive layer (B) (thickness = 10 μm)] / [Peeling layer (A2 ) (Thickness = 40 μm)] was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (C1) are shown in Table 1.

[Comparative Example 2]
Except that the thickness of the acrylic pressure-sensitive adhesive layer (B) was 30 μm, it was carried out in the same manner as in Comparative Example 1, and [Peeling layer (A1) (thickness = 40 μm)] / [Acrylic pressure-sensitive adhesive layer (B) (thickness = 30 [mu] m)] / [peeling layer (A2) (thickness = 40 [mu] m)] was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (C2) are shown in Table 1.

[Comparative Example 3]
Except for the thickness of the release layer (A1) being 80 μm, the same procedure as in Comparative Example 1 was carried out, and [release layer (A1) (thickness = 80 μm)] / [acrylic pressure-sensitive adhesive layer (B) (thickness = 10 μm)] / [Peeling layer (A2) (thickness = 10 μm)] A pressure-sensitive adhesive sheet (C3) having a laminated structure was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (C3) are shown in Table 1.

[Comparative Example 4]
The same procedure as in Comparative Example 1 was performed except that block polypropylene (trade name “NOVATEC PP FL6H” manufactured by Nippon Polypro Co., Ltd.) was used as a material for forming the release layer (A1), and [release layer (A1) (thickness = 40 μm). )] / [Acrylic pressure-sensitive adhesive layer (B) (thickness = 10 μm)] / [peeling layer (A2) (thickness = 10 μm)] A pressure-sensitive adhesive sheet (C4) having a laminated structure was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (C4) are shown in Table 1.

Example 9
Low density polyethylene (LDPE) (trade name “Petrocene 190”, manufactured by Tosoh Corp.) as a forming material of the release layer (A1 ′), and low density polyethylene (LDPE) (trade name, manufactured by Tosoh Corp.) as a forming material of the release layer (A1) “Petrocene 190”) added with 7.0% by weight of calcium carbonate (CaCO ₃ ) (trade name “BF300”, manufactured by Bihoku Powder Chemical Co., Ltd.) having an average particle size of 8 μm as fine particles (P), and acrylic adhesive Acrylic block copolymer (made by Kuraray, trade name “KURRITY LA2140e”, Mw = 8.0 × 10 ⁴ ) having an adhesive function as a material for forming the agent layer (B), and a material for forming the release layer (A2) Low density polyethylene (LDPE) (trade name “Petrocene 190” manufactured by Tosoh Corporation) and calcium carbonate (Ca) having an average particle diameter of 8 μm as fine particles (P) O _{3) (Bihoku} Funka Kogyo Co., Ltd., was put into trade name "BF300") extruder and a material obtained by adding 7.0 wt%, and were melt extruded from a T-die, [Peeling layer (A1 ') (Thickness = 30 μm)] / [Peeling layer (A1) (Thickness = 10 μm)] / [Acrylic adhesive layer (B) (Thickness = 10 μm)] / [Peeling layer (A2) (Thickness = 40 μm) A pressure-sensitive adhesive sheet (9) was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (9) are shown in Table 2.

Example 10
Except that the thickness of the release layer (A1 ′) was 70 μm and the thickness of the release layer (A2) was 80 μm, the same procedure as in Example 9 was carried out: [Peel layer (A1 ′) (thickness = 70 μm)] / [Peel Layer (A1) (thickness = 10 μm)] / [acrylic pressure-sensitive adhesive layer (B) (thickness = 10 μm)] / [peeling layer (A2) (thickness = 80 μm) laminated sheet (10) is obtained. It was.
The evaluation results for the pressure-sensitive adhesive sheet (10) are shown in Table 2.

[Comparative Example 5]
Low density polyethylene (LDPE) (trade name “Petrocene 190”, manufactured by Tosoh Corp.) as a forming material of the release layer (A1 ′), and low density polyethylene (LDPE) (trade name, manufactured by Tosoh Corp.) as a forming material of the release layer (A1) “Petrocene 190”) with fine particles (P) and an acrylic block copolymer having a pressure-sensitive adhesive function as a material for forming the acrylic pressure-sensitive adhesive layer (B) (trade name “KULARITY LA2140e”, Mw = 8. 0 × 10 ⁴ ) and low-density polyethylene (LDPE) (trade name “Petrocene 190” manufactured by Tosoh Corporation) as a forming material of the release layer (A2) are put into an extruder, and melt extrusion is performed from a T die. [Peeling layer (A1 ′) (Thickness = 30 μm)] / [Peeling layer (A1) (Thickness = 10 μm)] / [Acrylic adhesive layer (B) (Thickness = 10 μm)] / [Peeling layer A pressure-sensitive adhesive sheet (C5) having a laminated structure of (A2) (thickness = 40 μm) was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (C5) are shown in Table 2.

[Comparative Example 6]
[Release layer (A1 ′) (thickness = 70 μm)] / [Release], except that the thickness of the release layer (A1 ′) was 70 μm and the thickness of the release layer (A2) was 80 μm. Layer (A1) (thickness = 10 μm)] / [acrylic pressure-sensitive adhesive layer (B) (thickness = 10 μm)] / [peeling layer (A2) (thickness = 80 μm) is obtained. It was.
The evaluation results for the pressure-sensitive adhesive sheet (C6) are shown in Table 2.

Example 11
Low density polyethylene (LDPE) (trade name “Petrocene 190”, manufactured by Tosoh Corp.) as a forming material of the release layer (A1 ′), and low density polyethylene (LDPE) (trade name, manufactured by Tosoh Corp.) as a forming material of the release layer (A1) “Petrocene 190”) added with 7.0% by weight of calcium carbonate (CaCO ₃ ) (trade name “BF300”, manufactured by Bihoku Powder Chemical Co., Ltd.) having an average particle size of 8 μm as fine particles (P), and acrylic adhesive Acrylic block copolymer (made by Kuraray, trade name “KURRITY LA2140e”, Mw = 8.0 × 10 ⁴ ) having an adhesive function as a material for forming the agent layer (B), and a material for forming the release layer (A2) Low density polyethylene (LDPE) (trade name “Petrocene 190” manufactured by Tosoh Corporation) and calcium carbonate (Ca) having an average particle diameter of 8 μm as fine particles (P) O ₃₎ (Bihoku Funka Kogyo Co., Ltd., trade name "BF300") and a material obtained by adding 7.0 wt%, the peeling layer (A2 ') low-density polyethylene (LDPE) (manufactured by Tosoh as the material of the trade name “Petrocene 190”) is put into an extruder, and melt extrusion is performed from a T-die to obtain [peeling layer (A1 ′) (thickness = 30 μm)] / [peeling layer (A1) (thickness = 10 μm)] / [ A pressure-sensitive adhesive sheet (11) having a laminated structure of acrylic pressure-sensitive adhesive layer (B) (thickness = 10 μm)] / [peeling layer (A2) (thickness = 10 μm) / peeling layer (A2 ′) (thickness = 30 μm)] Obtained.
The evaluation results for the pressure-sensitive adhesive sheet (11) are shown in Table 3.

Example 12
Calcium carbonate (CaCO ₃ ) having an average particle size of 5.5 μm as fine particles (P) in the release layers (A1) and (A2) (trade name “Whiteon P-30” manufactured by Toyo Fine Chemical Co., Ltd.) 7.0% by weight [Peeling layer (A1 ′) (thickness = 30 μm)] / [Peeling layer (A1) (thickness = 10 μm)] / [Acrylic pressure-sensitive adhesive layer (B) A pressure-sensitive adhesive sheet (12) having a laminated structure of (thickness = 10 μm) / [peeling layer (A2) (thickness = 10 μm) / peeling layer (A2 ′) (thickness = 30 μm)] was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (12) are shown in Table 3.

Example 13
As the fine particles (P) in the release layers (A1) and (A2), 7.0% by weight of calcium carbonate (CaCO ₃ ) (trade name “Whiteon P-50” manufactured by Toyo Fine Chemical Co., Ltd.) having an average particle diameter of 19 μm is used. [Release layer (A1 ′) (thickness = 30 μm)] / [Peeling layer (A1) (thickness = 10 μm)] / [Acrylic pressure-sensitive adhesive layer (B) (thickness) = 10 μm)] / [Peeling layer (A2) (Thickness = 10 μm] / Peeling layer (A2 ′) (Thickness = 30 μm))] was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (13) are shown in Table 3.

Example 14
Example 11 except that 7.0% by weight of nepheline fine particles having a mean particle size of 7 μm (manufactured by Unimin, trade name “MINEX4”) were used as the fine particles (P) in the release layers (A1) and (A2). [Peeling layer (A1 ′) (thickness = 30 μm)] / [peeling layer (A1) (thickness = 10 μm)] / [acrylic pressure-sensitive adhesive layer (B) (thickness = 10 μm)] / [peeling layer ( A pressure-sensitive adhesive sheet (14) having a laminated structure of A2) (thickness = 10 μm) / peeling layer (A2 ′) (thickness = 30 μm) was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (14) are shown in Table 3.

Example 15
As a fine particle (P) in the release layers (A1) and (A2), 7.0% by weight of crosslinked polymethyl methacrylate fine particles having a mean particle diameter of 10 μm (trade name “Unipowder NMB-1020” manufactured by Nippon Oil Corporation) Except having used, it carried out similarly to Example 11, [Peeling layer (A1 ') (thickness = 30 micrometers)] / [Peeling layer (A1) (thickness = 10 micrometers)] / [Acrylic adhesive layer (B) ( Thickness = 10 μm)] / [Peeling layer (A2) (Thickness = 10 μm) / Peeling layer (A2 ′) (Thickness = 30 μm)] A pressure-sensitive adhesive sheet (15) was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (15) are shown in Table 3.

[Comparative Example 7]
As the fine particles (P) in the release layers (A1) and (A2), 7.0% by weight of calcium carbonate (CaCO ₃ ) (trade name “Whiteon P-10” manufactured by Toyo Fine Chemical Co., Ltd.) having an average particle diameter of 3 μm is used. [Release layer (A1 ′) (thickness = 30 μm)] / [Peeling layer (A1) (thickness = 10 μm)] / [Acrylic pressure-sensitive adhesive layer (B) (thickness) = 10 μm)] / [Peeling layer (A2) (Thickness = 10 μm] / Peeling layer (A2 ′) (Thickness = 30 μm))] was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (C7) are shown in Table 3.

[Comparative Example 8]
As the fine particles (P) in the release layers (A1) and (A2), 7.0% by weight of calcium carbonate (CaCO ₃ ) (trade name “Whiteon P-70” manufactured by Toyo Fine Chemical Co., Ltd.) having an average particle size of 26 μm is used. [Release layer (A1 ′) (thickness = 30 μm)] / [Peeling layer (A1) (thickness = 10 μm)] / [Acrylic pressure-sensitive adhesive layer (B) (thickness) = 10 μm)] / [Peeling layer (A2) (Thickness = 10 μm] / Peeling layer (A2 ′) (Thickness = 30 μm))] was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (C8) are shown in Table 3.
In Comparative Example 8, the laminate of the release layer (A1), the acrylic pressure-sensitive adhesive layer (B), and the release layer (A2) was not uniform, and a well-integrated laminate was not obtained.

[Comparative Example 9]
Low density polyethylene (LDPE) (trade name “Petrocene 190”, manufactured by Tosoh Corp.) as a forming material of the release layer (A1 ′), and low density polyethylene (LDPE) (trade name, manufactured by Tosoh Corp.) as a forming material of the release layer (A1) “Petrocene 190”) and an acrylic block copolymer having a pressure-sensitive adhesive function as a material for forming the acrylic pressure-sensitive adhesive layer (B) (trade name “KULARITY LA2140e”, Mw = 8.0 × 10 ⁴ ) And low density polyethylene (LDPE) (trade name “Petrocene 190” manufactured by Tosoh Corporation) as a forming material of the release layer (A2), and low density polyethylene (LDPE) (manufactured by Tosoh Corporation) as a forming material of the release layer (A2 ′). The product name “Petrocene 190”) was put into an extruder, and melt extrusion was performed from a T die to obtain [peeling layer (A1 ′) (thickness = 30 μm)] / [ Release layer (A1) (thickness = 10 μm)] / [acrylic adhesive layer (B) (thickness = 10 μm)] / [release layer (A2) (thickness = 10 μm) / release layer (A2 ′) (thickness = 30 μm) )]) Was obtained.
The evaluation results for the pressure-sensitive adhesive sheet (C9) are shown in Table 3.

  The pressure-sensitive adhesive sheet of the present invention is preferably used in, for example, electronic component manufacturing members, structural members, automobile members, and the like that require design properties, optical members that require visibility, and the like. For example, it can be used for bonding of members, protection applications, appearance adjustment applications, decoration applications, label applications, and the like.

100 Adhesive Sheet 11 Release Layer (A1)
12 Release layer (A2)
20 Acrylic adhesive layer (B)
31 Another release layer (A1 ′)
32 Another release layer (A2 ')
50 Fine particles (P)

Claims (6)

Acrylic pressure-sensitive adhesive layer (B), a release layer (A1) provided on one side of the acrylic pressure-sensitive adhesive layer (B), and a release layer provided on the other side of the acrylic pressure-sensitive adhesive layer (B) A pressure-sensitive adhesive sheet having (A2),
The release layer (A1) and the release layer (A2) each contain 0.1 wt% to 20 wt% of fine particles (P) having an average particle diameter of 4 μm to 25 μm.
Adhesive sheet.   Arithmetic average surface roughness Ra1 of the interface between the release layer (A1) and the acrylic pressure-sensitive adhesive layer (B), and arithmetic average surface of the interface between the release layer (A2) and the acrylic pressure-sensitive adhesive layer (B) The pressure-sensitive adhesive sheet according to claim 1, wherein the roughness Ra2 is 0.15 µm to 0.60 µm, respectively.   The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the acrylic pressure-sensitive adhesive layer (B) includes an acrylic block copolymer including an acrylate block structure and a methacrylate block structure.   The pressure-sensitive adhesive sheet according to claim 3, wherein the acrylic block copolymer has a weight average molecular weight of 30,000 to 300,000.   The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the release layer (A1) and the release layer (A2) each contain a polyolefin resin. The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, which is integrated by coextrusion molding.

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