Double-sided adhesive sheet with liner

Abstract

The present invention provides a liner-equipped double-sided adhesive sheet having liners on both sides thereof, wherein if either liner is peeled away first, the double-sided adhesive sheet remains only on one liner.　A liner-equipped double-sided adhesive sheet according to the present invention is provided with a double-sided adhesive sheet, a first liner that is directly and peelably disposed on one side of the double-sided adhesive sheet, and a second liner that is directly and peelably disposed on the other side of the double-sided adhesive sheet.

Description

[Technical field]

[0001] The present invention relates to a liner-attached double-sided pressure-sensitive adhesive sheet. [Background technology]

[0002] Double-sided pressure-sensitive adhesive sheets have been used in various situations. The double-sided pressure-sensitive adhesive sheet can exhibit adhesiveness due to the adhesive layer on both sides. In such double-sided pressure-sensitive adhesive sheets, a protective layer such as a release paper or a release liner (hereinafter also referred to as a liner) is often removably disposed on the adhesive surface until it is used.

[0003] The liners are disposed on both sides of the double-sided pressure-sensitive adhesive sheet, but when one liner is peeled off, a portion of the double-sided pressure-sensitive adhesive sheet components (effectively, the pressure-sensitive adhesive layer components) may adhere to the liner on the peeled side (the first-release liner), causing a phenomenon in which the double-sided pressure-sensitive adhesive sheet is held separately by both liners (a phenomenon known as "separation"). When this phenomenon occurs, the double-sided pressure-sensitive adhesive sheet may not be attached smoothly, or may cause a poor appearance even if attached (for example, Patent Document 1).

[0004] To address the above-mentioned problems, a technique is known in which the two liners have different peel strengths with respect to the PSA sheet. With this technique, when one liner is peeled off, the double-sided PSA sheet is held by the liner with the higher peel strength, preventing the separation phenomenon.

[0005] On the other hand, the double-sided pressure-sensitive adhesive sheet may be required to have removability. The removability may be imparted only to one side of the double-sided pressure-sensitive adhesive sheet, or may be imparted to both sides so that the removability can be manifested at different times. For example, a double-sided pressure-sensitive adhesive sheet in which one side loses its adhesiveness due to an external stimulus (e.g., heating, ultraviolet irradiation, etc.) is known as a pressure-sensitive adhesive sheet that can be preferably used as a temporary fixing material in processing electronic components, etc. Such a double-sided pressure-sensitive adhesive sheet can be used in such a manner that the side that loses its adhesiveness due to an external stimulus is the workbench side, and an adherend such as an electronic component is placed on the other side, the adherend is processed, etc., and then the double-sided pressure-sensitive adhesive sheet is peeled off from the workbench by an external stimulus. In this way, it is possible to provide the electronic component to the next process while it is fixed to the pressure-sensitive adhesive sheet.

[0006] In double-sided pressure-sensitive adhesive sheets having different adhesion and / or peeling mechanisms on both sides, such as the above-mentioned removability double-sided pressure-sensitive adhesive sheet, the side to be applied has a back and forth, and the order in which the liners arranged on both sides are peeled off may be specified. In such cases, the liner arranged on the side to be applied first needs to be peeled off with a lower peeling force than the other liner. However, in the above-mentioned "technology for providing a difference in peeling force from the pressure-sensitive adhesive sheet for two liners," it is not necessarily possible to configure the liner arranged on the side to be applied first so that it can be peeled off with a lower peeling force, and there are cases in which the technology cannot be effectively applied. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2003-201452 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made to solve the above-mentioned conventional problems, and its object is to provide a liner-attached double-sided adhesive sheet having liners on both sides, in which the double-sided adhesive sheet remains on only one of the liners regardless of which liner is peeled off first. [Means for solving the problem]

[0009] The liner-attached double-sided pressure-sensitive adhesive sheet of the present invention is a liner-attached double-sided pressure-sensitive adhesive sheet comprising a double-sided pressure-sensitive adhesive sheet, a first liner disposed directly on one side of the double-sided pressure-sensitive adhesive sheet in a releasable manner, and a second liner disposed directly on the other side of the double-sided pressure-sensitive adhesive sheet in a releasable manner, the double-sided pressure-sensitive adhesive sheet comprising a first pressure-sensitive adhesive layer disposed so as to be in contact with the first liner, the first pressure-sensitive adhesive layer containing heat-expandable microspheres, the peel force of the first liner from the double-sided pressure-sensitive adhesive sheet being 0.001 N / 50 mm to 2 N / 50 mm, and the product (I) of the cube of the thickness of the first liner and the elastic modulus of the first liner being 1×10 -7 ~1×10 -2 ( N m ) and the product (II) of the cube of the thickness of the second liner and the elastic modulus of the second liner is 1×10 -7 ~1×10 -2 ( N m ), and the product (I) of the cube of the thickness of the first liner and the elastic modulus of the first liner, the product (II) of the cube of the thickness of the second liner and the elastic modulus of the second liner, and the total of all layers (III) of the product of the cube of the single-layer thickness of each layer constituting the double-sided pressure-sensitive adhesive sheet and the single-layer elastic modulus satisfy the relationships (1) and (2) below. 0.001≦(I) / {(II)+(III)}≦1500 ···(1) 0.001≦(II) / {(I)+(III)}≦1500 ···(2) In one embodiment, the double-sided pressure-sensitive adhesive sheet comprises, in this order, the first pressure-sensitive adhesive layer, a substrate, and a second pressure-sensitive adhesive layer. In one embodiment, the total of all layers (III) of the product of the cube of the single layer thickness of each layer constituting the double-sided pressure-sensitive adhesive sheet and the single layer elastic modulus is 1×10 -6 N m ~1×10 -1 N m It is. In one embodiment, the product (I) of the cube of the thickness of the first liner and the elastic modulus of the first liner, the product (II) of the cube of the thickness of the second liner and the elastic modulus of the second liner, and the total of all layers (III) of the product of the cube of the single-layer thickness of each layer constituting the double-sided pressure-sensitive adhesive sheet and the single-layer elastic modulus satisfy the following relationship (3). 0.001≦{(I)+(II)} / (III)≦1500 ···(3) In one embodiment, the first liner and / or the second liner has a Si-Kα ray intensity of 0.01 to 500 kcps by fluorescent X-ray analysis. In one embodiment, at least one of the layers constituting the double-sided pressure-sensitive adhesive sheet is a colored layer. In one embodiment, the first liner and / or the second liner has a thickness of 10 μm to 100 μm. In one embodiment, the first liner and the second liner have different thicknesses. In one embodiment, the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive. In one embodiment, the acrylic pressure-sensitive adhesive comprises an acrylic polymer including a structural unit derived from a monomer having an active hydrogen group. In one embodiment, the content of the constituent units derived from the monomer having an active hydrogen group is 0.1% by weight to 20% by weight based on all the constituent units constituting the acrylic polymer. In one embodiment, the absolute value of the difference between the peel strength of the first liner from the double-sided pressure-sensitive adhesive sheet and the peel strength of the second liner from the double-sided pressure-sensitive adhesive sheet is 0.5 N / 50 mm or less. In one embodiment, the liner-attached double-sided PSA sheet is in a roll form. In one embodiment, the liner-attached double-sided pressure-sensitive adhesive sheet is used as a sheet for temporarily fixing a semiconductor chip during the manufacture of a CSP (Chip Size / Scale Package). In one embodiment, the liner-attached double-sided pressure-sensitive adhesive sheet is used as a sheet for temporarily fixing a semiconductor chip during the manufacture of a WLP (Wafer Level Package). In one embodiment, the liner-attached double-sided PSA sheet is used in processing that includes a step in which the second liner is first peeled off. Effect of the Invention

[0010] According to the present invention, it is possible to provide a liner-attached double-sided pressure-sensitive adhesive sheet having liners on both sides, in which the double-sided pressure-sensitive adhesive sheet remains on only one of the liners regardless of which liner is peeled off first. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic cross-sectional view of a liner-attached double-sided PSA sheet according to one embodiment of the present invention. [Diagram 2] FIG. 13 is a plan view illustrating evaluation b of liner peeling operability in the example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A. Overview of double-sided adhesive sheets with liner 1 is a schematic cross-sectional view of a liner-attached double-sided adhesive sheet according to one embodiment of the present invention. The liner-attached double-sided adhesive sheet 100 comprises a double-sided adhesive sheet 10, a first liner 20 disposed directly on one side of the double-sided adhesive sheet 10 in a releasable manner, and a second liner 30 disposed directly on the other side of the double-sided adhesive sheet 10 in a releasable manner. By disposing the first liner 20 and the second liner 30, it is possible to protect the adhesive layer from contamination and the like, and to prevent blocking of the roll-shaped or sheet-shaped double-sided adhesive sheet.

[0013] The double-sided pressure-sensitive adhesive sheet 10 is a sheet that exhibits adhesiveness on both sides. The double-sided pressure-sensitive adhesive sheet 10 includes at least a first pressure-sensitive adhesive layer 11 arranged so as to be in contact with a first liner 20. The first pressure-sensitive adhesive layer 11 contains heat-expandable microspheres. When the pressure-sensitive adhesive layer containing the heat-expandable microspheres is heated, the heat-expandable microspheres expand or foam, causing unevenness on the adhesive surface, resulting in a decrease or loss of adhesive strength. The double-sided pressure-sensitive adhesive sheet 10 including such a pressure-sensitive adhesive layer 11 can be easily peeled off by heating.

[0014] The double-sided pressure-sensitive adhesive sheet may be a single layer (i.e., may have a configuration including only a first pressure-sensitive adhesive layer) or may be a laminate including multiple layers. In one embodiment, as shown in FIG. 1, a double-sided pressure-sensitive adhesive sheet 10 includes a first pressure-sensitive adhesive layer 11, a substrate 12, and a second pressure-sensitive adhesive layer 13, in this order. This configuration is useful because it allows the use of various pressure-sensitive adhesives and also allows the selection of various means, such as extrusion, application, and coating, as a method for forming the pressure-sensitive adhesive layer.

[0015] The peel strength of the first liner and the second liner from the double-sided pressure-sensitive adhesive sheet is 0.001 N / 50 mm to 2 N / 50 mm. The product (I) of the cube of the thickness of the first liner and the elastic modulus of the first liner is 1×10 -7 ~1×10 -2 ( N m The second liner has a product (II) of the cube of the thickness and the elastic modulus of the second liner of 1×10 -7 ~1×10 -2 ( N m In addition, the product (I) of the cube of the thickness of the first liner and the elastic modulus of the first liner, the product (II) of the cube of the thickness of the second liner and the elastic modulus of the second liner, and the total of all layers (III) of the product of the cube of the single-layer thickness of each layer constituting the double-sided PSA sheet and the single-layer elastic modulus satisfy the following relationships (1) and (2). 0.001≦(I) / {(II)+(III)}≦1500 ···(1) 0.001≦(II) / {(I)+(III)}≦1500 ···(2)

[0016] According to the present invention, by focusing on the characteristics of the liners and configuring as described above, it is possible to provide a liner-attached double-sided pressure-sensitive adhesive sheet in which the double-sided pressure-sensitive adhesive sheet remains on only one liner, i.e., the tear-and-break phenomenon is prevented, regardless of which liner is peeled off first. The present invention has the following features: excellent operability in liner peeling, (i) the end of the liner (first peeling liner) is easy to pinch (easy to grab); (ii) a small part can be pinched up to trigger peeling; (iii) the folding angle of the liner when peeling the liner (preferably 90° to 180°, more preferably 120° to 180°, even more preferably 135° to 180°, even more preferably 150° to 180°, and particularly preferably 165° to 180°) is unlikely to fluctuate during the peeling operation. When the liner is peeled off in this way, the force acting during the peeling operation (peeling stress) is concentrated at the peeling point of the release liner (the part where the liner peeled off from the pressure-sensitive adhesive layer contacts the pressure-sensitive adhesive layer). As a result, the force required for peeling can be reduced, and tearing of the adhesive layer at the peeling point and poor peeling of the liner that needs to be peeled away can be prevented, with the double-sided adhesive sheet remaining on only one of the liners.

[0017] Generally, pressure-sensitive adhesive layers containing heat-expandable microspheres often have raised portions on the surface, which tends to reduce the concentration of peeling stress when the liner is peeled off. Therefore, the liner-attached double-sided pressure-sensitive adhesive sheet of the present invention, which has the above-mentioned effects while comprising a pressure-sensitive adhesive layer containing heat-expandable microspheres, is useful.

[0018] The above "(I) / {(II)+(III)}" is preferably 0.0035 to 250, more preferably 0.0035 to 150, even more preferably 0.0035 to 100, and particularly preferably 0.0035 to 30. The above "(II) / {(I)+(III)}" is preferably 0.003 to 500, more preferably 0.0035 to 300, even more preferably 0.0035 to 150, and particularly preferably 0.0035 to 130. Within such a range, the above effects are remarkable. Note that "the total (III) of the products of the cube of the single layer thickness and the single layer elastic modulus of each layer constituting the double-sided pressure-sensitive adhesive sheet" refers to the product (x1, x2, . . . ) of the cube of the single layer thickness and the single layer elastic modulus for each layer constituting the double-sided pressure-sensitive adhesive sheet, and the total value of the products (x1, x2, . . . ) for each layer. For example, if the double-sided pressure-sensitive adhesive sheet comprises a first pressure-sensitive adhesive layer, a substrate, and a second pressure-sensitive adhesive layer, the sum (x1+x2+x3) of the product (x1) of the cube of the thickness of the first pressure-sensitive adhesive layer and the elastic modulus of the first pressure-sensitive adhesive layer, the product (x2) of the cube of the thickness of the substrate and the elastic modulus of the substrate, and the product (x3) of the cube of the thickness of the second pressure-sensitive adhesive layer and the elastic modulus of the second pressure-sensitive adhesive layer corresponds to the "total (III) of all layers of the product of the cube of the single-layer thickness and the single-layer elastic modulus of each layer constituting the double-sided pressure-sensitive adhesive sheet." Furthermore, when the double-sided pressure-sensitive adhesive sheet comprises a first pressure-sensitive adhesive layer, an undercoat layer, a substrate, and a second pressure-sensitive adhesive layer, the sum (x1+x2+x3+x4) of the product (x1) of the cube of the thickness of the first pressure-sensitive adhesive layer and the elastic modulus of the first pressure-sensitive adhesive layer, the product (x2) of the cube of the thickness of the undercoat layer and the elastic modulus of the undercoat layer, the product (x3) of the cube of the thickness of the substrate and the elastic modulus of the substrate, and the product (x4) of the cube of the thickness of the second pressure-sensitive adhesive layer and the elastic modulus of the second pressure-sensitive adhesive layer corresponds to the "total (III) of all layers of the products of the cube of the single layer thicknesses and the single layer elastic moduli of each layer constituting the double-sided pressure-sensitive adhesive sheet."

[0019] In one embodiment, the product (I) of the cube of the thickness of the first liner and the elastic modulus of the first liner, the product (II) of the cube of the thickness of the second liner and the elastic modulus of the second liner, and the total of all layers (III) of the product of the cube of the single-layer thickness of each layer constituting the double-sided pressure-sensitive adhesive sheet and the single-layer elastic modulus satisfy the following relationship (3): 0.001≦{(I)+(II)} / (III)≦1500 ···(3) With this configuration, it is possible to obtain a liner-attached double-sided pressure-sensitive adhesive sheet and a double-sided pressure-sensitive adhesive sheet that are easy to cut and do not easily buckle when cut. Such an effect is particularly useful in a double-sided pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer that contains heat-expandable microspheres. {(I)+(II)} / (III) is more preferably 0.005 to 1000, even more preferably 0.015 to 500, particularly preferably 0.015 to 300, and most preferably 0.015 to 250.

[0020] In one embodiment, when the liner-attached double-sided pressure-sensitive adhesive sheet is used, the second liner is peeled off first. More specifically, the liner-attached double-sided pressure-sensitive adhesive sheet can be used by first peeling off the second liner, attaching an adherend (e.g., electronic component) to the exposed adhesive surface (e.g., the surface of the second pressure-sensitive adhesive layer), and then peeling off the first liner, and attaching the surface of the first pressure-sensitive adhesive layer to another adherend (e.g., a base). In such an embodiment, the adherend (e.g., electronic component) is temporarily fixed to the base via the double-sided pressure-sensitive adhesive sheet; the adherend is subjected to a predetermined processing; and then the adhesive strength of the first pressure-sensitive adhesive layer is reduced by heating, and the double-sided pressure-sensitive adhesive sheet with the adherend is peeled off from the base.

[0021] B. First liner, second liner Typically, the first liner and the second liner include a liner substrate and a release treatment layer disposed on at least one side of the liner substrate. The first liner and the second liner are disposed so that the release treatment layer faces the double-sided pressure-sensitive adhesive sheet. The first liner and the second liner may have the same configuration or different configurations.

[0022] As described above, the peel strength of the first liner from the double-sided pressure-sensitive adhesive sheet is 0.001 N / 50 mm to 2 N / 50 mm. The peel strength of the first liner from the double-sided pressure-sensitive adhesive sheet is preferably 0.01 N / 50 mm to 1.5 N / 50 mm, more preferably 0.05 N / 50 mm to 1 N / 50 mm, and particularly preferably 0.1 N / 50 mm to 0.8 N / 50 mm. By setting the peel strength of the liner from the double-sided pressure-sensitive adhesive sheet within the above range, the liner is not peeled off unnecessarily, the end face can be quickly picked up when the liner is peeled off, and the heat-expandable microspheres can be prevented from falling off from the first pressure-sensitive adhesive layer. The peel strength of the first liner from the double-sided adhesive sheet (and the peel strength of the second liner from the double-sided adhesive sheet) refers to the adhesive strength measured by peeling the liner from the double-sided adhesive sheet of the liner-attached double-sided adhesive sheet (peel angle: 180°, peel speed (tensile speed): 300 mm / min) in an environment of 23° C. The peel strength of the liner from the double-sided adhesive sheet can be adjusted by any appropriate method, such as the composition of the adhesive layer, the type of liner, or a surface treatment applied to the liner.

[0023] As described above, the peel strength of the second liner from the double-sided pressure-sensitive adhesive sheet is 0.001 N / 50 mm to 2 N / 50 mm. The peel strength of the second liner from the double-sided pressure-sensitive adhesive sheet is preferably 0.01 N / 50 mm to 1.5 N / 50 mm, more preferably 0.05 N / 50 mm to 1 N / 50 mm, and particularly preferably 0.1 N / 50 mm to 0.8 N / 50 mm.

[0024] The peel strength of the first liner from the double-sided PSA sheet and the peel strength of the second liner from the double-sided PSA sheet may be the same or different. In one embodiment, the absolute value of the difference between the peel strength of the first liner from the double-sided PSA sheet and the peel strength of the second liner from the double-sided PSA sheet is preferably 0.5 N / 50 mm or less, more preferably 0.4 N / 50 mm or less, and even more preferably 0.2 N / 50 mm or less. According to the present invention, it is possible to obtain a liner-attached double-sided PSA sheet in which the double-sided PSA sheet remains on only one of the liners, regardless of which liner is peeled first, without providing a difference in peel strength between the first liner and the second liner.

[0025] The thickness of the first liner is preferably 5 μm to 250 μm, more preferably 10 μm to 200 μm, even more preferably 20 to 150 μm, and most preferably 30 to 100 μm. Within such a range, a liner can be obtained that is excellent in identifiability and can easily maintain the peel angle (fold back angle) during peeling. In addition, a liner can be obtained that is easy to wind up when wound around a roll and prevents the problem of the liner separating from the pressure-sensitive adhesive layer during punching (so-called "floating"). In one embodiment, the thickness of the first liner is 10 μm to 100 μm.

[0026] The thickness of the second liner is preferably 5 μm to 250 μm, more preferably 10 μm to 200 μm, further preferably 20 to 150 μm, and most preferably 30 to 100 μm. In one embodiment, the thickness of the second liner is 10 μm to 100 μm.

[0027] The thickness of the first liner and the thickness of the second liner may be the same or different. In one embodiment, the thickness of the first liner and the thickness of the second liner are different. By using liners with different thicknesses, it is easy to identify the liner to be peeled off.

[0028] The elastic modulus of the first liner (substantially the liner substrate) is 500 MPa to 5000 MPa, more preferably 500 MPa to 4000 MPa, and even more preferably 700 MPa to 4000 MPa. Within such a range, a liner can be obtained that is excellent in operability, easy to wind up when wound into a roll, and prevents the problem of the liner separating from the adhesive layer during punching (so-called "floating"). In the specification, the elastic modulus means the elastic modulus measured by the nanoindentation method in an environment of 23°C. The elastic modulus measured by the nanoindentation method means the elastic modulus obtained by continuously measuring the load applied to the indenter and the indentation depth during loading and unloading when the indenter is pressed into a sample (which may be a liner substrate) and then obtaining a load-indentation depth curve. The conditions for measuring the elastic modulus by the nanoindentation method will be described later.

[0029] The elastic modulus of the second liner (substantially the liner substrate) is 500 MPa to 5000 MPa, more preferably 500 MPa to 4000 MPa, and further preferably 700 MPa to 4000 MPa. The elastic modulus of the first liner and the elastic modulus of the second liner may be the same or different.

[0030] As described above, the product (I) of the cube of the thickness of the first liner and the elastic modulus of the first liner is 1×10 -7 ~1×10 -2 ( N m ). The product (I) is preferably 1×10 -6 ~5×10 -3 ( N m ), more preferably 5×10 -6 ~2×10 -3 ( N m Within such a range, a liner can be obtained which is easy to fold back and which can easily maintain the peel angle (fold back angle) during peeling.

[0031] As described above, the product (II) of the cube of the thickness of the second liner and the elastic modulus of the second liner is 1×10 -7~1×10 -2 ( N m ). The product (II) is preferably 1×10 -6 ~5×10 -3 ( N m ), more preferably 5×10 -6 ~2×10 -3 ( N m ), particularly preferably 5 × 10 -6 ~1.5×10 -3 ( N m ), most preferably 5×10 -6 ~1.308×10 -3 (N m) Within such a range, a liner can be obtained that is easy to fold back and can easily maintain the peel angle (fold back angle) during peeling. The above "product (I)" of the first liner and the above "product (II)" of the second liner may be the same or different.

[0032] The liner substrate may be made of any suitable material. The liner substrate may be, for example, a plastic film, a plastic sheet, or various sheet-like materials such as paper, cloth, nonwoven fabric, metal foil, or a plastic laminate thereof, or a laminate of plastics. Among them, plastic films and plastic sheets (hereinafter referred to as plastic films) are most preferable from the viewpoint of handling and cost. The material of the plastic film may be selected as necessary from the viewpoint of strength, heat resistance, and the like. For example, olefin-based resins having α-olefin as a monomer component, such as polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer (EVA); polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyvinyl chloride (PVC); polyphenylene sulfide (PPS); amide-based resins such as polyamide (nylon) and fully aromatic polyamide (aramid); polyether ether ketone (PEEK), polyimide, polyetherimide, polystyrene, and acrylic resins may be mentioned. These materials can be used alone or in combination of two or more. The plastic film may be any of an unstretched film, a uniaxially oriented film, and a biaxially oriented film. These films may be laminated films consisting of two or more film layers, or from the viewpoint of handling, a film containing a lubricant such as inert particles may be appropriately added.

[0033] Any suitable treatment may be adopted as the treatment for forming the release treatment layer. In one embodiment, the release treatment layer is a silicone treatment layer. As the silicone, a reactive silicone compound whose main component is dimethylpolysiloxane and has a functional group required for crosslinking (curing) may be preferably used. This is because it can be applied to a film in a low molecular weight state, and can be cured after application to form a release treatment layer that is resistant to abrasion, etc. Examples of functional groups of reactive silicone compounds include vinyl groups, epoxy groups, alkoxy groups, and isocyanato groups.

[0034] The silicone-treated layer is formed, for example, by diluting the reactive silicone compound in a solvent or the like to adjust the concentration, and applying and heating the mixture using a gravure coater or the like. Heating promotes the drying of the solvent and the curing reaction. It is preferable to use a catalyst that promotes the curing reaction in combination. Examples of catalysts that can be used include complexes of metals such as platinum, palladium, rhodium, zirconium, and tin, organic bases such as amines, and organic acids such as acetic acid.

[0035] In one embodiment, the first liner and / or the second liner (substantially, the release treatment layer of each liner) has an intensity of Si-Kα radiation by fluorescent X-ray analysis of 0.01 to 500 kcps (preferably 0.5 to 250 kcps, more preferably 1.0 to 150 kcps, and even more preferably 1.05 to 100 kcps). In such a range, the liner can be peeled off from the adhesive layer with a small force, so that it is easy to quickly pick up one end of the liner in a small amount. In addition, the adhesion between the liner / adhesive layer becomes sufficient, and unnecessary peeling of the liner can be prevented. The intensity of Si-Kα radiation by fluorescent X-ray analysis is a value obtained by measuring the Si intensity of the release treatment agent layer and the non-release treatment agent layer by fluorescent X-ray analysis, respectively, and subtracting the strength of the non-release treatment agent layer from the strength of the release treatment agent layer. The strength can be adjusted by controlling the release treatment layer formation conditions, such as the application amount, concentration, application speed, and drying of the release treatment agent.

[0036] In one embodiment, the first liner and the second liner are different colors. A liner-attached double-sided pressure-sensitive adhesive sheet configured in this manner can be obtained, for example, by coloring one of the liners (for example, the liner substrate). If both liners are different colors, the front and back of the liner-attached double-sided pressure-sensitive adhesive sheet become clear, making it easy to identify the liner to be peeled off.

[0037] C. Double-sided adhesive sheet As described above, the double-sided pressure-sensitive adhesive sheet comprises a first pressure-sensitive adhesive layer. In one embodiment, the double-sided pressure-sensitive adhesive sheet comprises a first pressure-sensitive adhesive layer, a substrate, and a second pressure-sensitive adhesive layer, in this order. In one embodiment, the double-sided pressure-sensitive adhesive sheet further comprises an undercoat layer disposed between the first pressure-sensitive adhesive layer and the substrate. The undercoat layer makes it possible to obtain a double-sided pressure-sensitive adhesive sheet that has excellent conformability to an adherend. When the first pressure-sensitive adhesive layer containing heat-expandable microspheres is heated, the heat-expandable microspheres expand, causing deformation in the thickness direction; however, the undercoat layer suppresses deformation in the direction toward the substrate, improving peelability.

[0038] The initial adhesive strength at 23°C when the first adhesive layer of the double-sided adhesive sheet is attached to polyethylene terephthalate is preferably 0.5 N / 20 mm or more, more preferably 0.5 N / 20 mm to 20 N / 20 mm, and even more preferably 0.5 N / 20 mm to 15 N / 20 mm. Within such a range, for example, a double-sided adhesive sheet useful as a temporary fixing sheet used in the manufacture of electronic components can be obtained. In this specification, the initial adhesive strength refers to the adhesive strength in a state where there is no adhesive strength reduction due to the expansion of the heat-expandable microspheres, and means the adhesive strength in a state where there is no thermal history of 50°C or more. In addition, the adhesive strength refers to the adhesive strength measured by a method according to JIS Z 0237:2000 (lamination conditions: 1 round trip with a 2 kg roller, peel speed: 300 mm / min, peel angle 180°).

[0039] The adhesive strength of the first adhesive layer of the double-sided adhesive sheet when attached to polyethylene terephthalate is preferably reduced to 0.2 N / 20 mm or less (preferably 0.1 N / 20 mm or less) by heating. The heating temperature is preferably 90°C to 300°C, more preferably 100°C to 280°C.

[0040] The adhesive strength at 23°C when the second adhesive layer of the double-sided adhesive sheet is attached to polyethylene terephthalate is preferably 0.5 N / 20 mm or more, more preferably 0.5 N / 20 mm to 20 N / 20 mm, and even more preferably 0.5 N / 20 mm to 15 N / 20 mm.

[0041] The thickness of the double-sided pressure-sensitive adhesive sheet is preferably 3 μm to 300 μm, more preferably 5 μm to 150 μm, and even more preferably 10 μm to 100 μm.

[0042] The total thickness (III) of all layers constituting the double-sided pressure-sensitive adhesive sheet is preferably 1×10 -6 N m ~1×10 -1 N m and more preferably 5×10 -6 N m ~5×10 -2 N m and more preferably 5×10 -6 N m ~3×10 -2 N m Within this range, a double-sided PSA sheet can be obtained that is self-supporting, has excellent operability in lamination, and is also excellent in flexibility. This effect is particularly useful in a double-sided PSA sheet that includes a first PSA layer that contains heat-expandable microspheres.

[0043] In one embodiment, at least one of the layers constituting the double-sided pressure-sensitive adhesive sheet is a colored layer. When there are multiple colored layers, it is preferable that each layer is a different color. With these configurations, the front and back of the liner-attached double-sided pressure-sensitive adhesive sheet are clearly distinguished, making it easy to identify the liner to be peeled off. Note that coloring refers to a state in which any or all light in the visible light region (250 nm to 700 nm) is absorbed and / or reflected. Any appropriate method can be used as a method for coloring any one layer.

[0044] As the colorant, a pigment or a dye can be used. As the pigment, for example, organic pigments such as acrylic pigments, azo pigments, polyazo pigments, anthraquinone pigments, quinacridone pigments, isoindoline pigments, isoindolinone pigments, phthalocyanine pigments, perylene pigments, DPP pigments, fluorescent pigments, condensed polycyclic pigments, and colored resin particles can be used, and inorganic pigments such as carbon black, synthetic silica, chromium oxide, iron oxide, titanium oxide, zinc sulfide, calcined pigments, and natural mica can be used. As the dye, acid dyes, reactive dyes, direct dyes, disperse dyes, cationic dyes, and polymer dyes can be used. As the ink, a commercially available product such as "NB300" manufactured by Dainichi Seikagaku Co., Ltd. can be used. It should be noted that coloring can also be achieved by mixing a colorant into the adhesive layer. In addition, when the composition of the adhesive layer has a fine structure of a size of about the visible light wavelength due to, for example, microphase separation between a hydrophilic composition and a hydrophobic composition, a phenomenon in which the coloring occurs according to the size, that is, a so-called structural color, can be exhibited, and coloring utilizing this phenomenon can also be used.

[0045] C-1. First adhesive layer The first pressure-sensitive adhesive layer contains heat-expandable microspheres as described above. The first pressure-sensitive adhesive layer may further contain a pressure-sensitive adhesive.

[0046] Examples of the adhesive constituting the first adhesive layer include acrylic adhesives, rubber adhesives, and silicone adhesives. Among them, acrylic adhesives can be preferably used. In addition, an active energy ray curable acrylic adhesive (hereinafter, active energy ray curable adhesive) may be used as the adhesive. Details of the adhesive are described in, for example, JP 2015-168711 A. The description of this publication is incorporated herein by reference.

[0047] (Acrylic adhesive) In one embodiment, an acrylic adhesive is used as the adhesive. Examples of the acrylic adhesive include an acrylic adhesive having an acrylic polymer (homopolymer or copolymer) using one or more (meth)acrylic acid alkyl esters as a monomer component as a base polymer.

[0048] Specific examples of the (meth)acrylic acid alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, and ) C1-20 alkyl esters of (meth)acrylic acid such as nonyl acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, nonadecyl (meth)acrylate, and eicosyl (meth)acrylate. Among these, preferred are (meth)acrylic acid alkyl esters having a linear or branched alkyl group having 4 to 20 carbon atoms (more preferably 6 to 20, particularly preferably 8 to 18), and more preferably 2-ethylhexyl (meth)acrylate.

[0049] The acrylic polymer may contain units corresponding to other monomer components copolymerizable with the alkyl (meth)acrylate, if necessary, for the purpose of modifying properties such as cohesive strength, heat resistance, and crosslinkability. Examples of such monomer components include carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride monomers such as maleic anhydride and itanoic anhydride; hydroxyl group-containing monomers such as hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, hydroxydecyl (meth)acrylate, hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate; sulfonic acid group-containing monomers such as styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid; (N-substituted) amide monomers such as N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, and N-methylolpropane(meth)acrylamide; aminoalkyl(meth)acrylate monomers such as aminoethyl(meth)acrylate, N,N-dimethylaminoethyl(meth)acrylate, and t-butylaminoethyl(meth)acrylate; alkoxyalkyl(meth)acrylate monomers such as methoxyethyl(meth)acrylate and ethoxyethyl(meth)acrylate; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; itaconimide monomers such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, and N-laurylitaconimide;succinimide monomers such as N-(meth)acryloyloxymethylene succinimide, N-(meth)acryloyl-6-oxyhexamethylene succinimide, and N-(meth)acryloyl-8-oxyoctamethylene succinimide; vinyl monomers such as vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinyl carboxylic acid amides, styrene, α-methylstyrene, and N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, and methoxyethyl (meth)acrylate. glycol-based acrylic ester monomers such as ethylene glycol and methoxypolypropylene glycol (meth)acrylate; acrylic ester monomers having a heterocycle, a halogen atom, a silicon atom, or the like, such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicone (meth)acrylate; polyfunctional monomers such as hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate; olefin-based monomers such as isoprene, butadiene, and isobutylene;Examples of the monomer component include vinyl ether monomers such as vinyl ether. These monomer components may be used alone or in combination of two or more. Among the above, more preferred are carboxyl group-containing monomers (particularly preferably acrylic acid) or hydroxyl group-containing monomers (particularly preferably hydroxyethyl (meth)acrylate). The content of the structural unit derived from the carboxyl group-containing monomer is preferably 0.1% by weight to 10% by weight, more preferably 0.5% by weight to 5% by weight, and particularly preferably 1% by weight to 4% by weight, based on the total structural units constituting the acrylic polymer. The content of the structural unit derived from the hydroxyl group-containing monomer is preferably 0.1% by weight to 20% by weight, more preferably 0.5% by weight to 10% by weight, and particularly preferably 1% by weight to 7% by weight, based on the total structural units constituting the acrylic polymer. In this specification, (meth)acrylic means acrylic and / or methacrylic.

[0050] In one embodiment, the acrylic polymer contains a constituent unit derived from a monomer having an active hydrogen group. By containing the constituent unit derived from a monomer having an active hydrogen group, the acrylic polymer undergoes microphase separation and scatters light with wavelengths in the visible range to become colored (milky white to pale yellow), making it easier to identify the end face of the liner when it is picked up.

[0051] The content of the constituent units derived from the monomer having the active hydrogen group is preferably 0.1% by weight to 20% by weight, more preferably 0.5% by weight to 10% by weight, and particularly preferably 1% by weight to 7% by weight, based on the total constituent units constituting the acrylic polymer. Examples of the monomer having an active hydrogen group include (meth)acrylic acid, 2-hydroxyethyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate.

[0052] The acrylic adhesive may contain any suitable additives as necessary, such as crosslinkers, tackifiers, plasticizers (e.g., trimellitic acid ester plasticizers, pyromellitic acid ester plasticizers, etc.), pigments, dyes, fillers, antioxidants, conductive materials, antistatic agents, UV absorbers, light stabilizers, release regulators, softeners, surfactants, flame retardants, antioxidants, etc.

[0053] Examples of the crosslinking agent contained in the acrylic adhesive include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, as well as urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, amine-based crosslinking agents, etc. Among these, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred.

[0054] Specific examples of the isocyanate-based crosslinking agent contained in the acrylic pressure-sensitive adhesive include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate; and isocyanate adducts such as trimethylolpropane / tolylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate L"), trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate HL"), and isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., product name "Coronate HX"). The content of the isocyanate-based crosslinking agent can be set to any appropriate amount depending on the desired adhesive strength, and is typically 0.1 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight, per 100 parts by weight of the base polymer.

[0055] Examples of the epoxy crosslinking agent contained in the acrylic adhesive include N,N,N',N'-tetraglycidyl-m-xylylenediamine, diglycidylaniline, 1,3-bis(N,N-glycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Company, Inc., product name "Tetrad C"), 1,6-hexanediol diglycidyl ether (manufactured by Kyoeisha Chemical Company, Inc., product name "Epolite 1600"), neopentyl glycol diglycidyl ether (manufactured by Kyoeisha Chemical Company, Inc., product name "Epolite 1500NP"), ), ethylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., product name "Epolight 40E"), propylene glycol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., product name "Epolight 70P"), polyethylene glycol diglycidyl ether (manufactured by Nippon Oil & Fats Co., Ltd., product name "Epiol E-400"), polypropylene glycol diglycidyl ether (manufactured by Nippon Oil & Fats Co., Ltd., product name "Epiol P-200"), sorbitol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, product name "Denacol" Examples of the epoxy crosslinking agent include glycerol polyglycidyl ether (manufactured by Nagase Chemtex Corporation, trade name "Denacol EX-611"), glycerol polyglycidyl ether (manufactured by Nagase Chemtex Corporation, trade name "Denacol EX-314"), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (manufactured by Nagase Chemtex Corporation, trade name "Denacol EX-512"), sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, o-phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. The content of the epoxy crosslinking agent can be set to any appropriate amount depending on the desired adhesive strength, and is typically 0.01 to 10 parts by weight, more preferably 0.03 to 5 parts by weight, relative to 100 parts by weight of the base polymer.

[0056] The tackifier contained in the acrylic pressure-sensitive adhesive may be any appropriate tackifier, such as a tackifier resin. Specific examples of the tackifier resin include rosin-based tackifier resins (e.g., unmodified rosin, modified rosin, rosin phenol-based resins, rosin ester-based resins, etc.), terpene-based tackifier resins (e.g., terpene-based resins, terpene phenol-based resins, styrene-modified terpene-based resins, aromatic modified terpene-based resins, hydrogenated terpene-based resins), hydrocarbon-based tackifier resins (e.g., aliphatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aromatic hydrocarbon resins (e.g., styrene-based resins, xylene-based resins, etc.), aliphatic and aromatic petroleum resins, aliphatic and alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone-based resins, coumarone-indene resins, etc.), phenol-based tackifier resins (e.g., alkylphenol-based resins, xylene formaldehyde-based resins, resols, novolacs, etc.), ketone-based tackifier resins, polyamide-based tackifier resins, epoxy-based tackifier resins, elastomer-based tackifier resins, etc. Among them, rosin-based tackifier resins, terpene-based tackifier resins, or hydrocarbon-based tackifier resins (such as styrene-based resins) are preferred. The tackifiers may be used alone or in combination of two or more. The amount of the tackifier added is preferably 5 to 100 parts by weight, more preferably 10 to 50 parts by weight, based on 100 parts by weight of the base polymer.

[0057] (thermal expandable microspheres) The heat-expandable microspheres may be any suitable type of heat-expandable microspheres, so long as they are capable of expanding or foaming upon heating. For example, the heat-expandable microspheres may be microspheres having a substance that easily expands upon heating encapsulated in an elastic shell. Such heat-expandable microspheres may be produced by any suitable method, such as a coacervation method or an interfacial polymerization method.

[0058] Examples of substances that easily expand when heated include low-boiling liquids such as propane, propylene, butene, normal butane, isobutane, isopentane, neopentane, normal pentane, normal hexane, isohexane, heptane, octane, petroleum ether, methane halides, and tetraalkylsilanes; azodicarbonamide that gasifies by thermal decomposition; and the like.

[0059] Examples of materials constituting the shell include polymers composed of nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, and fumaronitrile; carboxylic acid monomers such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and citraconic acid; vinylidene chloride; vinyl acetate; (meth)acrylic acid esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, and β-carboxyethyl acrylate; styrene monomers such as styrene, α-methylstyrene, and chlorostyrene; and amide monomers such as acrylamide, substituted acrylamide, methacrylamide, and substituted methacrylamide. Polymers composed of these monomers may be homopolymers or copolymers. Examples of such copolymers include vinylidene chloride-methyl methacrylate-acrylonitrile copolymer, methyl methacrylate-acrylonitrile-methacrylonitrile copolymer, methyl methacrylate-acrylonitrile copolymer, acrylonitrile-methacrylonitrile-itaconic acid copolymer, and the like.

[0060] The heat-expandable microspheres may be made of an inorganic or organic foaming agent, such as ammonium carbonate, ammonium hydrogen carbonate, sodium hydrogen carbonate, ammonium nitrite, sodium borohydride, and various azides. Examples of organic foaming agents include fluorinated alkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; azo compounds such as azobisisobutyronitrile, azodicarbonamide and barium azodicarboxylate; hydrazine compounds such as paratoluenesulfonylhydrazide, diphenylsulfone-3,3'-disulfonylhydrazide, 4,4'-oxybis(benzenesulfonylhydrazide) and allylbis(sulfonylhydrazide); semicarbazide compounds such as p-toluylenesulfonylsemicarbazide and 4,4'-oxybis(benzenesulfonylsemicarbazide); triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; and N-nitroso compounds such as N,N'-dinitrosopentamethylenetetramine and N,N'-dimethyl-N,N'-dinitrosoterephthalamide.

[0061] The particle size of the heat-expandable microspheres before heating is preferably 0.5 μm to 80 μm, more preferably 5 μm to 45 μm, further preferably 10 μm to 20 μm, and particularly preferably 10 μm to 15 μm. Thus, the particle size of the heat-expandable microspheres before heating, expressed in terms of average particle size, is preferably 6 μm to 45 μm, more preferably 15 μm to 35 μm. The particle size and average particle size are values ​​determined by a particle size distribution measurement method using a laser scattering method.

[0062] The heat-expandable microspheres preferably have an appropriate strength so that they do not burst until their volumetric expansion rate reaches at least 5 times, more preferably at least 7 times, and even more preferably at least 10 times. When such heat-expandable microspheres are used, their adhesive strength can be efficiently reduced by heat treatment.

[0063] The content of the heat-expandable microspheres in the pressure-sensitive adhesive layer can be appropriately set depending on the desired decrease in adhesive strength, etc. The content of the heat-expandable microspheres is, for example, 1 to 150 parts by weight, preferably 10 to 130 parts by weight, and more preferably 25 to 100 parts by weight, relative to 100 parts by weight of the base polymer forming the pressure-sensitive adhesive layer.

[0064] The arithmetic surface roughness Ra of the first pressure-sensitive adhesive layer before the heat-expandable microspheres expand (i.e., before heating) is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less. In a pressure-sensitive adhesive layer containing heat-expandable microspheres, raised portions due to the heat-expandable microspheres may occur. However, if the surface roughness before heating is within the above range, the liner can be peeled off without problems such as tearing or tearing of the pressure-sensitive adhesive layer caused by the peeling stress concentrating on the raised portions during liner peeling, and a double-sided pressure-sensitive adhesive sheet with excellent adhesion to the adherend can be obtained. The arithmetic surface roughness Ra can be adjusted, for example, by the thickness of the first pressure-sensitive adhesive layer, the surface smoothness of the substrate when the double-sided pressure-sensitive adhesive sheet is formed by transferring the first pressure-sensitive adhesive layer formed on the substrate, the drying conditions when the first pressure-sensitive adhesive layer is formed, and the like.

[0065] The thickness of the first pressure-sensitive adhesive layer is preferably 5 μm to 70 μm, more preferably 10 μm to 60 μm, even more preferably 15 μm to 55 μm, and most preferably 20 μm to 50 μm. Within this range, a double-sided pressure-sensitive adhesive sheet can be obtained that is excellent in operability of liner peeling, operability during application, adhesiveness, smoothness, and deformability upon heating. In one embodiment, the thickness of the first pressure-sensitive adhesive layer is 23 μm to 47 μm. Within this range, from the viewpoint of smoothness of the pressure-sensitive adhesive layer surface, a double-sided pressure-sensitive adhesive sheet that is particularly suitable when the adherend is a base substrate used in CSP or WLP can be obtained.

[0066] The elastic modulus of the first pressure-sensitive adhesive layer is preferably 0.001 MPa to 10 MPa, and more preferably 0.01 MPa to 8 MPa. Within this range, a double-sided pressure-sensitive adhesive sheet can be obtained that is excellent in operability in liner peeling, operability during application, adhesiveness, smoothness, and deformability upon heating. In one embodiment, the elastic modulus of the first pressure-sensitive adhesive layer is preferably 0.05 MPa to 4 MPa, and more preferably 0.1 MPa to 3 MPa. Within this range, from the viewpoint of smoothness of the pressure-sensitive adhesive layer surface, a double-sided pressure-sensitive adhesive sheet that is particularly suitable when the adherend is a base substrate used in CSP or WLP can be obtained.

[0067] C-2. Second adhesive layer The second adhesive layer may contain any appropriate adhesive. Examples of adhesives constituting the second adhesive layer include acrylic adhesives, rubber adhesives, silicone adhesives, and the like. Among them, acrylic adhesives may be preferably used. In addition, an active energy ray curable acrylic adhesive (hereinafter, active energy ray curable adhesive) may be used as the adhesive. Details of the adhesive are described in, for example, JP 2015-168711 A. The description of this publication is incorporated herein by reference.

[0068] In one embodiment, the second pressure-sensitive adhesive layer includes the acrylic pressure-sensitive adhesive described in Section C-1. As described above, the acrylic pressure-sensitive adhesive includes an acrylic polymer as a base polymer. In one embodiment, the acrylic polymer includes a constituent unit derived from a monomer having an active hydrogen group. The content of the constituent unit derived from the monomer having an active hydrogen group is preferably 0.1 wt % to 20 wt %, more preferably 0.5 wt % to 10 wt %, and particularly preferably 1 wt % to 7 wt %, based on the total constituent units constituting the acrylic polymer.

[0069] The thickness of the second pressure-sensitive adhesive layer is preferably 1 μm to 50 μm, more preferably 2 μm to 60 μm, even more preferably 3 μm to 35 μm, and most preferably 5 μm to 35 μm. Within such a range, a double-sided pressure-sensitive adhesive sheet can be obtained that is excellent in operability during liner peeling, operability during application, adhesiveness, and smoothness. In one embodiment, the thickness of the second pressure-sensitive adhesive layer is preferably 2 μm to 35 μm, and more preferably 3 μm to 25 μm. Within such a range, from the viewpoints of embedding into uneven surfaces and suppressing standoff, a double-sided pressure-sensitive adhesive sheet that is particularly suitable when the adherend is a semiconductor chip used in CSP or WLP can be obtained.

[0070] The elastic modulus of the second pressure-sensitive adhesive layer is preferably 0.001 MPa to 10 MPa, more preferably 0.01 MPa to 8 MPa. Within this range, a double-sided pressure-sensitive adhesive sheet excellent in operability of liner peeling, operability during application, adhesiveness, and smoothness can be obtained. In one embodiment, the elastic modulus of the second pressure-sensitive adhesive layer is preferably 0.05 MPa to 4 MPa, more preferably 0.1 MPa to 3 MPa. Within this range, a double-sided pressure-sensitive adhesive sheet that is particularly suitable for use when the adherend is a semiconductor chip used in CSP or WLP can be obtained, from the viewpoint of embedding into uneven surfaces. When the second pressure-sensitive adhesive layer contains an active energy ray-curable pressure-sensitive adhesive, the second pressure-sensitive adhesive layer is cured by irradiation with active energy rays, and the elastic modulus is preferably 1 MPa to 200 MPa, more preferably 5 MPa to 150 MPa, and even more preferably 10 MPa to 100 MPa.

[0071] C-3. Undercoat layer The undercoat layer includes any appropriate adhesive. Examples of the adhesive constituting the undercoat layer include acrylic adhesives, rubber adhesives, silicone adhesives, and the like. Among them, acrylic adhesives can be preferably used. Furthermore, an active energy ray curable acrylic adhesive (hereinafter, active energy ray curable adhesive) may be used as the adhesive. Preferably, the adhesive constituting the undercoat layer is the same adhesive as the adhesive constituting the first adhesive layer.

[0072] The thickness of the undercoat layer is preferably 1 μm to 40 μm, more preferably 5 μm to 35 μm, and even more preferably 10 μm to 30 μm. Within such a range, a double-sided PSA sheet can be obtained that has excellent operability in peeling the liner and that suppresses the influence of the heat-expandable microspheres on the substrate side when heated.

[0073] The elastic modulus of the undercoat layer is preferably 0.001 MPa to 10 MPa, more preferably 0.01 MPa to 8 MPa, and more preferably 0.5 MPa to 5 MPa. Within such ranges, a double-sided pressure-sensitive adhesive sheet can be obtained that has excellent operability in peeling off the liner and suppresses the influence on the substrate side when the heat-expandable microspheres are heated. When the undercoat layer contains an active energy ray-curable pressure-sensitive adhesive, the undercoat layer is cured by irradiation with active energy rays, and the elastic modulus of the undercoat layer is preferably 1 MPa to 200 MPa, more preferably 5 MPa to 150 MPa, and even more preferably 10 MPa to 100 MPa.

[0074] C-4. Base material The substrate may be made of any suitable material. As the substrate, various sheet-like materials such as paper, cloth, nonwoven fabric, metal foil, plastic laminates thereof, and laminates of plastics can be used. Among them, plastic films and plastic sheets (hereinafter referred to as plastic films) are most preferable from the viewpoint of handling and cost. The material of the plastic film can be selected as necessary from the viewpoint of strength, heat resistance, and the like. For example, olefin-based resins having α-olefin as a monomer component such as polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, and ethylene-vinyl acetate copolymer (EVA); polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate (PBT); polyvinyl chloride (PVC); polyphenylene sulfide (PPS); amide-based resins such as polyamide (nylon) and fully aromatic polyamide (aramid); polyether ether ketone (PEEK), polyimide, polyetherimide, polystyrene, and acrylic resins can be mentioned. These materials can be used alone or in combination of two or more. The plastic film may be any of an unstretched film, a uniaxially oriented film, and a biaxially oriented film. These films may be laminated films consisting of two or more film layers, or from the viewpoint of handling, a film containing a lubricant such as inert particles may be appropriately added.

[0075] The thickness of the substrate is preferably 200 μm or less, more preferably 1 μm to 200 μm, further preferably 5 μm to 200 μm, particularly preferably 10 μm to 200 μm, particularly preferably 20 μm to 200 μm, and most preferably 30 μm to 200 μm. If the thickness is within such a range, it can contribute to improving the liner releasability, and a substrate excellent in strength, flexibility, suppleness, buckling resistance, etc. can be obtained.

[0076] The elastic modulus of the substrate is preferably 500 MPa to 5000 MPa, more preferably 500 MPa to 4000 MPa, and further preferably 700 MPa to 4000 MPa. Within such a range, it is possible to improve the liner releasability and obtain a substrate excellent in strength, flexibility, suppleness, buckling resistance, etc.

[0077] The substrate may be subjected to a surface treatment, such as corona treatment, chromate treatment, ozone exposure, flame exposure, high-voltage shock exposure, ionizing radiation treatment, or coating with a primer.

[0078] In order to improve the visibility of the edge of the liner and to improve the anchoring of the base material and the adhesive layer, the base material may be printed with ink, etc. For ink, Dainichi Seika Chemical's "NB300" or the like can be used.

[0079] C-5. Manufacturing method of double-sided adhesive sheet The double-sided pressure-sensitive adhesive sheet can be produced by any suitable method. Examples of the method for producing the double-sided pressure-sensitive adhesive sheet of the present invention include a method of directly coating a composition containing a pressure-sensitive adhesive on a substrate, or a method of coating a composition containing a pressure-sensitive adhesive on any suitable substrate and transferring the formed coating layer to the substrate. A liner-attached double-sided pressure-sensitive adhesive sheet may also be obtained by a method of coating a composition containing a pressure-sensitive adhesive on a liner and laminating the formed laminate (first liner / first pressure-sensitive adhesive layer, second pressure-sensitive adhesive layer / second liner) to a substrate. The pressure-sensitive adhesive-containing composition may contain any suitable solvent.

[0080] The first pressure-sensitive adhesive layer can be formed by coating a substrate with a composition containing heat-expandable microspheres, a pressure-sensitive adhesive, and any suitable solvent. Alternatively, the pressure-sensitive adhesive layer containing heat-expandable microspheres may be formed by sprinkling heat-expandable microspheres on the pressure-sensitive adhesive coating layer and then embedding the heat-expandable microspheres in the pressure-sensitive adhesive using a laminator or the like.

[0081] When the double-sided pressure-sensitive adhesive sheet has the above-mentioned undercoat layer, the undercoat layer can be formed, for example, by applying a composition for forming the undercoat layer (adhesive) onto the substrate or onto the first pressure-sensitive adhesive layer.

[0082] Any suitable coating method can be adopted as the coating method of the pressure-sensitive adhesive. For example, each layer can be formed by coating and then drying. Examples of the coating method include coating methods using a multi-coater, a die coater, a gravure coater, an applicator, etc. Examples of the drying method include natural drying, heat drying, etc. The heating temperature when heat drying can be set to any suitable temperature depending on the characteristics of the material to be dried.

[0083] D.Applications The liner-attached double-sided pressure-sensitive adhesive sheet can be preferably used as a temporary fixing sheet when processing any appropriate member (e.g., electronic components such as semiconductor chips). In one embodiment, the liner-attached double-sided pressure-sensitive adhesive sheet can be used as a sheet for temporarily fixing a semiconductor chip when manufacturing a CSP (Chip Size / Scale Package) or a WLP (Wafer Level Package). In one embodiment, the liner-attached double-sided pressure-sensitive adhesive sheet is used in processing including a step in which the second liner is first peeled off.

[0084] In one embodiment, the liner-attached double-sided PSA sheet is in a roll form. EXAMPLES

[0085] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. In the examples, "parts" and "%" are by weight unless otherwise specified.

[0086] [Production Example 1] Production of liner a (thickness: 12 μm) An addition type silicone treatment agent (manufactured by Shin-Etsu Silicones, main agent "KS-774": 100 parts by weight, catalyst "CAT PL-3": 0.4 parts by weight) was dissolved in a mixed solvent of heptane and hexane (mixture weight ratio 1:1) to prepare a stripping treatment agent solution with the treatment agent concentration adjusted to 0.9%. Next, the release agent solution was applied to one side of a PET film (manufactured by Toray Industries, product name "Lumirror S10", thickness 12 μm) using the gravure method, and dried in a hot air oven to obtain a liner a with a thickness of 12 μm. The Si-Kα radiation intensity of the obtained liner was 13 (kcps) (the measurement method will be described later).

[0087] [Production Example 2] Production of liner b (thickness: 75 μm) A 75 μm-thick PET film (manufactured by Toray Industries, Inc., product name "Lumirror S10") was used as the PET film, and a 75 μm-thick liner b was obtained in the same manner as in Production Example 1. The Si-Kα radiation intensity of the obtained liner was 80 (kcps).

[0088] [Production Example 3] Production of liner c (thickness: 38 μm) A 38 μm-thick PET film (manufactured by Toray Industries, Inc., product name "Lumirror S10") was used as the PET film, and a 38 μm-thick liner c was obtained in the same manner as in Production Example 1. The Si-Kα radiation intensity of the obtained liner was 3.2 (kcps).

[0089] [Production Example 4] Production of Liner d (Thickness: 50 μm) A 50 μm-thick PET film (manufactured by Toray Industries, Inc., product name "Lumirror S10") was used as the PET film, and a 50 μm-thick liner d was obtained in the same manner as in Production Example 1. The Si-Kα radiation intensity of the obtained liner was 35 (kcps).

[0090] [Production Example 5] Production of Liner e (thickness: 26 μm) A 26 μm thick liner e was obtained in the same manner as in Production Example 1, except that a 26 μm thick olefin film (manufactured by Toray Industries, Inc., product name "Torayfan") was used instead of the PET film. The Si-Kα radiation intensity of the obtained liner was 12 (kcps).

[0091] [Manufacturing Example 6] Liner f (thickness: 38 μm) A PET film with a release treatment layer having a thickness of 38 μm (manufactured by Mitsubishi Plastics, Inc., product name "MRF38") was prepared as the liner f. The Si-Kα radiation intensity of the liner was 18 (kcps).

[0092] [Production Example 7] Production of liner g (thickness: 25 μm) A 25 μm-thick liner g was obtained in the same manner as in Production Example 1, except that a 25 μm-thick PET film (manufactured by Toray Industries, Inc., product name "Lumirror S10") was used as the PET film. The Si-Kα radiation intensity of the obtained liner was 1.1 (kcps).

[0093] [Production Example 8] Production of Liner h (Thickness: 5 μm) A 5 μm-thick liner h was obtained in the same manner as in Production Example 1, except that a 5 μm-thick PET film (manufactured by Toray Industries, Inc., product name "Lumirror S10") was used as the PET film. The Si-Kα radiation intensity of the obtained liner was 1.0 (kcps).

[0094] [Production Example 9] Production of Liner i (Thickness: 75 μm) A 75 μm-thick liner i was obtained in the same manner as in Production Example 1, except that a 75 μm-thick olefin film (manufactured by Toray Industries, Inc., product name "Torayfan") was used instead of the PET film. The Si-Kα radiation intensity of the obtained liner was 13 (kcps).

[0095] [Production Example 10] Production of Base Polymer 1 70 parts of ethyl acrylate, 3 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 5 parts of methyl methacrylate, 3.5 parts of 2-hydroxyethyl acrylate, and 0.2 parts of benzoyl peroxide as a polymerization initiator were added to toluene, and the mixture was heated to obtain a toluene solution of an acrylic copolymer (polymer 1). Note that 3.1% by weight of the repeating units derived from monomers constituting polymer 1 are repeating units derived from monomers having an active hydrogen group.

[0096] [Production Example 11] Production of Base Polymer 2 50 parts of butyl acrylate, 50 parts of ethyl acrylate, 5 parts of acrylic acid, 0.2 parts of 2-hydroxyethyl acrylate, and 0.2 parts of benzoyl peroxide as a polymerization initiator were added to toluene, and the mixture was heated to obtain a toluene solution of an acrylic copolymer (polymer 2). Note that 4.9% by weight of the repeating units derived from monomers constituting polymer 2 are repeating units derived from monomers having an active hydrogen group.

[0097] [Production Example 12] Production of Base Polymer 3 70 parts of methyl acrylate, 2 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 10 parts of acrylic acid, and 0.2 parts of benzoyl peroxide as a polymerization initiator were added to ethyl acetate, and the mixture was heated to obtain an ethyl acetate solution of an acrylic copolymer (polymer 3). Note that 8.9% by weight of the repeating units derived from monomers constituting polymer 3 are repeating units derived from monomers having an active hydrogen group.

[0098] [Production Example 13] Production of Base Polymer 4 50 moles of butyl acrylate, 50 moles of ethyl acrylate, 24 moles of 2-hydroxyethyl acrylate, and benzoyl peroxide (0.2 parts per 100 parts of the total of butyl acrylate, ethyl acrylate, and 2-hydroxyethyl acrylate) as a polymerization initiator were added to toluene, and the mixture was heated to obtain a toluene solution of an acrylic copolymer (polymer 4). Note that 19.6% by weight of the repeating units derived from monomers constituting polymer 4 are repeating units derived from monomers having an active hydrogen group.

[0099] [Production Example 14] Production of Base Polymer 5 In toluene, 50 moles of butyl acrylate, 50 moles of ethyl acrylate, 24 moles of 2-hydroxyethyl acrylate, and benzoyl peroxide (0.2 parts per 100 parts of the total of butyl acrylate, ethyl acrylate, and 2-hydroxyethyl acrylate) were added as a polymerization initiator, and then heated to obtain a copolymer solution. To this copolymer solution, 2-isocyanatoethyl acrylate was added in an amount equivalent to 78 mole % of the hydroxyl groups derived from 2-hydroxyethyl acrylate in the solution, and then heated to add 2-isocyanatoethyl methacrylate to the hydroxyl groups derived from the 2-hydroxyethyl acrylate, thereby obtaining a toluene solution of an acrylic copolymer (polymer 5) having a methacrylate group in the side chain. It should be noted that 3.4 weight % of the repeating units derived from the monomers constituting polymer 5 are repeating units derived from monomers having active hydrogen groups.

[0100] [Example 1] (Preparation of Undercoat Layer / Substrate Laminate) A mixed solution A was prepared by mixing a toluene solution of polymer 1 (polymer 1:100 parts) and 3 parts of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Industries, Ltd., product name "Coronate L"). Lumirror S10 (thickness: 25 μm) manufactured by Toray Industries, Inc. was used as the substrate, and the mixed solution A was applied to one side of the substrate using an applicator so that the thickness after solvent evaporation (drying) would be 13 μm. The solvent was then evaporated (dried) to obtain an undercoat layer / substrate laminate. (Preparation of First Liner / First Pressure-Sensitive Adhesive Layer (Containing Heat-Expandable Microspheres) Laminate) A mixed solution B was prepared by mixing a toluene solution of polymer 1 (polymer 1:100 parts), 1.5 parts of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Industries, Ltd., product name "Coronate L"), 0.05 parts of a crosslinking aid (manufactured by Tokyo Fine Chemical Co., Ltd., product name "OL-1"), 10 parts of a tackifier resin (manufactured by Sumitomo Bakelite Co., Ltd., product name "Sumilite PR12603"), 30 parts of thermally expandable microspheres (manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., product name "FN-180SSD"), and 0.5 parts of a colorant (manufactured by Dainichiseika Chemicals Mfg. Co., Ltd., product name "DYMICS SZ-7510 Green") The mixed solution B was applied to the release treatment agent-coated surface of the liner a so that the thickness after solvent evaporation (drying) would be 35 μm. Thereafter, the solvent was evaporated (dried) to obtain a first liner / first pressure-sensitive adhesive layer laminate. (Preparation of First Liner / First Pressure-Sensitive Adhesive Layer (Containing Heat-Expandable Microspheres) / Undercoat Layer / Base Material Laminate) The first liner / first pressure-sensitive adhesive layer laminate and the undercoat layer / substrate laminate were bonded together so that the first pressure-sensitive adhesive layer and the undercoat layer faced each other to obtain a first liner / first pressure-sensitive adhesive layer (containing heat-expandable microspheres) / undercoat layer / substrate laminate. (Preparation of Second Pressure-Sensitive Adhesive Layer / Second Liner Laminate) A mixed solution C was prepared by mixing a toluene solution of polymer 1 (polymer 1:100 parts), 1.5 parts of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., product name "Coronate L"), 0.05 parts of a crosslinking assistant (manufactured by Tokyo Fine Chemical Co., Ltd., product name "OL-1"), and 10 parts of a plasticizer (manufactured by DIC Corporation, product name "Monocizer W700"). The mixed solution C was applied to the release treatment agent-coated surface of the liner b so that the thickness after solvent evaporation (drying) would be 10 μm. Thereafter, the solvent was evaporated (dried) to obtain a second pressure-sensitive adhesive layer / second liner laminate. (Preparation of double-sided adhesive sheet with liner) A first liner / first pressure-sensitive adhesive layer (containing heat-expandable microspheres) / undercoat layer / substrate laminate and a second pressure-sensitive adhesive layer / second liner laminate were bonded together with the substrate and the second pressure-sensitive adhesive layer facing each other to obtain a liner-attached double-sided pressure-sensitive adhesive sheet (first liner / double-sided pressure-sensitive adhesive sheet (first pressure-sensitive adhesive layer (containing heat-expandable microspheres) / undercoat layer / substrate / second pressure-sensitive adhesive layer) / second liner).

[0101] [Examples 2 to 18, 20 to 23, Comparative Example 1] A liner-attached double-sided PSA sheet was obtained in the same manner as in Example 1, except that the composition of each layer was as shown in Tables 1 to 4. The contents of each component are as follows: <Crosslinking agent> Tetrad C: Mitsubishi Gas Chemical Company, product name "Tetrad C", epoxy crosslinking agent <Tackifier> SUMILITE PR12603: Manufactured by Sumitomo Bakelite Co., Ltd., product name "SUMILITE RESIN PR12603" S145: Manufactured by Yasuhara Chemical Co., Ltd., product name "YS Polyster S145" <Thermally expandable microspheres> F-30D: Matsumoto Yushi Seiyaku Co., Ltd., product name "Matsumoto Microsphere F-30D", foaming (expansion) start temperature: 70℃~80℃, maximum expansion temperature: 110℃~120℃, average particle size 10μm~18μm FN-180SSD: Matsumoto Yushi Pharmaceutical Co., Ltd., product name "Matsumoto Microsphere FN-180SSD", foaming (expansion) start temperature: 135℃~150℃, maximum expansion temperature: 165℃~180℃, average particle size 15μm~25μm F-230D: Matsumoto Yushi Pharmaceutical Co., Ltd., product name "Matsumoto Microsphere F-230D" F-50D: Matsumoto Yushi Pharmaceutical Co., Ltd., product name "Matsumoto Microsphere F-50D" <Coloring agent> DYMICS SZ-7200 Red: Manufactured by Dainichiseika Color & Chemicals Co., Ltd., product name "DYMICS SZ-7200 Red"

[0102] [Example 19] (Preparation of Undercoat Layer / Substrate Laminate) A mixed solution was prepared by mixing a toluene solution of polymer 4 (polymer 4: 100 parts), 40 parts of ultraviolet-curable urethane acrylate (UV7620EA: manufactured by Nippon Synthetic Chemical Industry Co., Ltd., product name "Shikou UV-7620EA") as an active energy ray reactive oligomer, 0.5 parts of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Industry Co., Ltd., product name "Tetrad C"), and 3 parts of an energy ray polymerization initiator (manufactured by BASF Japan Ltd., product name "Irgacure 651") with the same solvent (toluene) as that in the mixed solution to adjust the viscosity to a viscosity that is easy to apply, and mixed solution A' was obtained. A film was prepared by applying (solid printing) blue printing ink CVL-PR (DIC Graphics) to one side of Lumirror S10 (thickness 50 μm) manufactured by Toray Industries, Inc. using a gravure coater so that the coating thickness after drying would be 2 μm. The mixed solution A' was applied to one side of this substrate using an applicator, and then the solvent was evaporated (dried) to obtain a laminate consisting of a precursor layer of the undercoat layer / substrate. (Preparation of First Liner / First Pressure-Sensitive Adhesive Layer (Containing Heat-Expandable Microspheres) Laminate) A toluene solution of polymer 4 (polymer 4: 100 parts), 40 parts of ultraviolet-curable urethane acrylate (UV7620EA: manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Shikou UV-7620EA") as an active energy ray reactive oligomer, 0.5 parts of an epoxy-based crosslinking agent (manufactured by Mitsubishi Gas Chemical Industry Co., Ltd., trade name "Tetrad C"), 3 parts of an energy ray polymerization initiator (manufactured by BASF Japan Ltd., trade name "Irgacure 651"), and 30 parts of thermally expandable microspheres (manufactured by Matsumoto Yushi Seiyaku Co., Ltd., trade name "F-30D") were mixed to prepare a mixed liquid. The same solvent (toluene) as that in the mixed liquid was further added to the mixed liquid to adjust the viscosity to a viscosity that was easy to apply, and mixed liquid B' was obtained. The above mixed solution B' was applied to the release treatment agent-coated surface of the liner c. Thereafter, the solvent was evaporated (dried) to obtain a laminate consisting of the first liner / precursor layer of the first pressure-sensitive adhesive layer. (Preparation of First Liner / First Pressure-Sensitive Adhesive Layer (Containing Heat-Expandable Microspheres) / Undercoat Layer / Base Material Laminate) A laminate consisting of a first liner / precursor layer for a first adhesive layer and a laminate consisting of a precursor layer for an undercoat layer / substrate were bonded together so that the precursor layer for the first adhesive layer and the precursor layer for the undercoat layer faced each other, to obtain a laminate consisting of a first liner / precursor layer for a first adhesive layer (containing heat-expandable microspheres) / precursor layer for an undercoat layer / substrate. (Preparation of Second Pressure-Sensitive Adhesive Layer / Second Liner Laminate) A mixed solution C' was prepared by mixing a toluene solution of polymer 5 (polymer 1:100 parts), 0.2 parts of an isocyanate-based crosslinking agent (manufactured by Nippon Polyurethane Co., Ltd., product name "Coronate L"), and 3 parts of an energy beam polymerization initiator (manufactured by BASF Japan, product name "Irgacure 651"). The above mixed solution C' was applied to the release treatment agent-coated surface of the liner f. Thereafter, the solvent was evaporated (dried) to obtain a laminate consisting of the precursor layer of the second pressure-sensitive adhesive layer / the second liner. (Preparation of double-sided adhesive sheet with liner) A laminate consisting of a first liner / precursor layer of the first adhesive layer (containing heat-expandable microspheres) / precursor layer of the undercoat layer / substrate and a laminate consisting of a precursor layer of the second adhesive layer / second liner were bonded together so that the substrate and the precursor layer of the second adhesive layer faced each other. Then, an ultraviolet irradiator (manufactured by Nitto Seiki Co., Ltd., product name "UM810 (high pressure mercury lamp light source)") was used to irradiate each precursor layer with an integrated light amount of 300 mJ / cm2. 2 In this manner, a double-sided pressure-sensitive adhesive sheet with a liner (first liner / double-sided pressure-sensitive adhesive sheet (first pressure-sensitive adhesive layer (containing heat-expandable microspheres; thickness: 25 μm) / undercoat layer (25 μm) / substrate / second pressure-sensitive adhesive layer (10 μm)) / second liner) was obtained.

[0103] [evaluation] The liner-attached double-sided PSA sheets obtained in the Examples and Comparative Examples were subjected to the following evaluations, with the results shown in Tables 1 to 5. (1) Liner peeling operability evaluation a A liner-attached double-sided adhesive sheet (50 mm x 100 mm) was attached to a metal plate (SUS304 plate, thickness 3 mm) via double-sided tape (manufactured by Nitto Denko Corporation, product name "No. 500") with the first liner facing up, to prepare a measurement sample (a). In addition, a liner-attached double-sided adhesive sheet (50 mm x 100 mm) was attached to a metal plate (SUS304 plate, thickness 3 mm) via double-sided tape (manufactured by Nitto Denko Corporation, product name "No. 500") with the second liner facing up, to prepare a measurement sample (b). For the measurement sample (a) and the measurement sample (b), the upper liner was pinched with bare hands and folded back in an environment of 23° C. / 65% RH, and the liner peeling operability was evaluated according to the following criteria. Excellent (circle in the table): Able to turn around within 30 seconds. Good (△ in the table): It took more than 30 seconds, but I was able to turn around. Unacceptable (× in the table): The adhesive layer was torn or unnecessary lifting (peeling) occurred before folding, resulting in a result that does not qualify as "excellent" or "good." (2) Liner peeling operability evaluation b Measurement samples (a) and (b) were prepared in the same manner as in (1) above. The liner peeling operability of the measurement sample (a) and the measurement sample (b) was evaluated in an environment of 23° C. / 65% RH by the following procedure. A tape (manufactured by Nichiban Co., Ltd., product name "Cellotape (registered trademark) No. 405" (industrial use, 18 mm width)) was attached to the upper liner as shown in FIG. 2 (a plan view from above showing the measurement sample) to prepare a measurement sample (c). The measurement sample (c) was attached to a tensile tester with a thermostatic chamber (product name "Shimadzu Autograph AG-120kN" manufactured by Shimadzu Corporation). The tape was then pulled in the longitudinal direction (rightward on the paper) under conditions of a set peel angle of 180°, a constant force, and a peel speed of 300 mm / min, and the state in which the upper liner was separated from the double-sided pressure-sensitive adhesive sheet was observed and evaluated according to the following criteria. Excellent (◯ in the table): The upper liner was peeled off while maintaining a peel angle of 180°. Good (△ in the table): The peel angle of 180° was not maintained, but the upper liner was peeled off. Unacceptable (X in the table): The adhesive layer was torn off, peeling at the interface between the lower liner and the adhesive layer, and other separation phenomena were observed. (3) Roll winding test A 2 m long x 0.3 m wide double-sided PSA sheet with a liner was wrapped around a pipe with an outer diameter of 5 cm with the second liner on the outside. Both ends of the double-sided PSA sheet with a liner were secured with terminal tape (manufactured by Nichiban Co., Ltd., product name "Cellotape (registered trademark) No. 405" (industrial use, 18 mm width), 20 mm x 18 mm). The double-sided PSA sheet with liner wrapped around the pipe as described above was stored in an environment of 40° C. / 50% RH for 72 hours. Thereafter, the appearance of the liner-attached double-sided PSA sheet was visually inspected, and the roll-winding property was evaluated according to the following criteria. Excellent (◯ in the table): No change in appearance before and after storage. Good (△ in the table): A change in appearance was observed to the extent that the terminal tape became loose, but the wrapping was not loose. Unacceptable (X in the table): The wrapping was loose and peeling of the terminal tape was confirmed, and peeling of the liner was confirmed. (4) Liner peel strength The second liner was peeled off from a double-sided adhesive sheet with liner (50 mm x 180 mm), and the second adhesive layer was attached to a metal plate (SUS304 plate, thickness: 3 mm) via double-sided tape (manufactured by Nitto Denko Corporation, product name "No. 500") to prepare a measurement sample. This measurement sample was set in a tensile tester equipped with a thermostatic chamber (product name "Shimadzu Autograph AG-120kN" manufactured by Shimadzu Corporation) and left for 30 minutes. Next, the first liner was peeled off from the double-sided pressure-sensitive adhesive sheet at a separation angle of 180° and a peel speed (pulling speed) of 300 mm / min in an environment of 23° C. / 55% RH, and the peel force of the first liner was measured. In addition, the first liner was peeled off from a double-sided adhesive sheet with liner (50 mm x 180 mm), and the first adhesive layer was attached to a metal plate (SUS304 plate, thickness: 3 mm) via double-sided tape (manufactured by Nitto Denko Corporation, product name "No. 500") to prepare a measurement sample, and the peel force of the second liner was measured in the same manner as above. (5) Elastic modulus The liner-attached double-sided pressure-sensitive adhesive sheet was cut in the thickness direction using a microtome, and each layer was identified by visually inspecting the cut surface or by observing with an optical microscope, and the nanoindenter elastic modulus of the layers constituting the liner-attached double-sided pressure-sensitive adhesive sheet was measured. The elastic modulus of the first pressure-sensitive adhesive layer is the elastic modulus of the area where there are no heat-expandable microspheres. The elastic modulus was obtained by pressing a probe (indenter) against the object to be measured and numerically processing the displacement-load hysteresis curve using software (triboscan) provided with the measuring device (average value of three measurements). The nanoindenter device and measurement conditions are as follows. Apparatus and measurement conditions: Nanoindenter; Triboindenter manufactured by Hysitron Inc. Measurement method: Single indentation method ·Measurement temperature: 25℃ Push-in speed: approx. 1000nm / sec Indentation depth: approx. 800 nm Probe: Diamond, Berkovich type (triangular pyramid type) (6) Thickness The liner-attached double-sided PSA sheet was cut in the thickness direction with a trimming cutter and subjected to a Pt-Pd sputtering treatment, after which the cut surface was observed with a Hitachi High-Technologies Corporation S3400N low-vacuum scanning electron microscope (SEM) to measure the thickness. The measurement conditions for SEM observation are as follows: Observed image: ESD image Acceleration voltage: 10 kV ·Magnification: 600x When the interface between the constituent layers was unclear, the following Raman spectroscopy was also used to determine the interface between the layers, and then the thickness was measured. (Raman spectrum measurement) Excitation wavelength: 532nm Measurement wave number range: 300~3600cm-1 Grating: 600gr / mm Objective lens: x100 Measurement time: 0.2 sec / spectrum Measurement range: 20x40μm Number of measurements: 100 x 200 Detector: EMCCD (7) Measurement of Si-Kα line intensity of liner X-ray fluorescence analysis was performed on 100 points randomly selected on the liner surface (release-treated surface). More specifically, the Si-Kα radiation intensity (i) of the surface of the liner in contact with the adhesive layer (the surface coated with a release agent) and the Si-Kα radiation intensity (ii) of the surface not in contact with the adhesive layer (the surface not coated with a release agent) were measured, the absolute value of the value obtained by subtracting the value of (ii) from the value of (i) was calculated, and the average value of the 100 points was taken as the Si-Kα radiation intensity of the liner. The Si-Kα radiation intensity is the intensity at a wavelength of 7.125 angstroms measured using the following device. Equipment: Rigaku ZSX100e Analysis area: 30mmφ Analysis element: Si Analytical crystal: RX4 Output: 50kV, 70mA

[0104] [Table 1]

[0105] [Table 2]

[0106] [Table 3]

[0107] [Table 4]

[0108] [Table 5] [Explanation of symbols]

[0109] 10 Double-sided adhesive sheet 11 First adhesive layer 12 Base material 13 Second adhesive layer 20 First Liner 30 The Second Diner 100 Adhesive Sheet

Claims

1. A double-sided adhesive sheet; a first liner disposed directly and releasably on one surface of the double-sided PSA sheet; a liner-attached double-sided PSA sheet comprising a second liner disposed directly and releasably on the other surface of the double-sided PSA sheet, the double-sided PSA sheet comprises a first PSA layer disposed in contact with the first liner; the first pressure-sensitive adhesive layer contains heat-expandable microspheres, the peel strength of the first liner from the double-sided PSA sheet is 0.001 N / 50 mm to 2 N / 50 mm; The product (I) of the cube of the thickness of the first liner and the elastic modulus of the first liner is 1×10 －７ ~1×10 －２ (N·m), The product (II) of the cube of the thickness of the second liner and the elastic modulus of the second liner is 1×10 －７ ~1×10 －２ (N·m), the product (I) of the cube of the thickness of the first liner and the elastic modulus of the first liner, the product (II) of the cube of the thickness of the second liner and the elastic modulus of the second liner, and a total of all layers (III) of the product of the cube of the single-layer thickness of each layer constituting the double-sided PSA sheet and the single-layer elastic modulus satisfy the following relationships (1), (2), and (3), the peel strength of the first liner from the double-sided adhesive sheet is different from the peel strength of the second liner from the double-sided adhesive sheet, and the absolute value of the difference between the peel strength of the first liner from the double-sided adhesive sheet and the peel strength of the second liner from the double-sided adhesive sheet is 0.5 N / 50 mm or less; Double-sided adhesive sheet with liner. 0.0035≦(I) / {(II)+(III)}≦150...(1) 0.0035≦(II) / {(I)+(III)}≦300...(2) 0.015≦{(I)+(II)} / (III)≦500 (3)

2. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1 , comprising the first pressure-sensitive adhesive layer, a substrate, and a second pressure-sensitive adhesive layer in this order.

3. The total of all layers (III) of the product of the cube of the single layer thickness of each layer constituting the double-sided pressure-sensitive adhesive sheet and the single layer elastic modulus is 1×10 －６ N m to 1 x 10 －１ The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the compressive strength is N·m.

4. 4. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1, wherein the first liner and / or the second liner have a Si-Kα ray intensity of 0.01 to 500 kcps by fluorescent X-ray analysis.

5. 5. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1, wherein at least one of the layers constituting the double-sided pressure-sensitive adhesive sheet is a colored layer.

6. 6. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1, wherein the first liner and / or the second liner has a thickness of 10 μm to 100 μm.

7. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1 , wherein the first liner and the second liner have different thicknesses.

8. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1 , wherein the first pressure-sensitive adhesive layer and / or the second pressure-sensitive adhesive layer comprises an acrylic pressure-sensitive adhesive.

9. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 8 , wherein the acrylic pressure-sensitive adhesive comprises an acrylic polymer that includes a structural unit derived from a monomer having an active hydrogen group.

10. 10. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 9, wherein the content of the structural units derived from the monomer having an active hydrogen group is 0.1% by weight to 20% by weight based on all structural units constituting the acrylic polymer.

11. 11. A liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1, wherein the absolute value of the difference between the peel strength of the first liner from the double-sided pressure-sensitive adhesive sheet and the peel strength of the second liner from the double-sided pressure-sensitive adhesive sheet is 0.5 N / 50 mm or less.

12. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1 , which is in a roll form.

13. 13. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1, which is used as a sheet for temporarily fixing a semiconductor chip during the manufacture of a CSP (Chip Size / Scale Package).

14. 13. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1, which is used as a sheet for temporarily fixing a semiconductor chip during the manufacture of a WLP (wafer level package).

15. 15. The liner-attached double-sided pressure-sensitive adhesive sheet according to claim 1, which is used in processing that includes a step in which the second liner is first peeled off.

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