WO2022185610A1

WO2022185610A1 - Liner-equipped double-sided adhesive sheet

Info

Publication number: WO2022185610A1
Application number: PCT/JP2021/040262
Authority: WO
Inventors: 高正平山; 昭徳西尾
Original assignee: 日東電工株式会社
Priority date: 2021-03-05
Filing date: 2021-11-01
Publication date: 2022-09-09
Also published as: JP7652879B2; TWI809659B; TW202235567A; KR20230141836A; JPWO2022185610A1; CN116897196A

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

Double-sided adhesive sheet with liner

The present invention relates to a double-sided pressure-sensitive adhesive sheet with a liner.

Conventionally, double-sided adhesive sheets have been used in various situations. The double-sided pressure-sensitive adhesive sheet can exhibit pressure-sensitive adhesive properties on both sides due to the pressure-sensitive adhesive layer. In such a double-sided PSA sheet, a protective layer such as a release paper or a release liner (hereinafter also referred to as a liner) is often releasably arranged on the adhesive surface until it is used. .

The liner is placed on both sides of the double-sided pressure-sensitive adhesive sheet. When one liner is peeled off, the double-sided pressure-sensitive adhesive sheet component (substantially, pressure-sensitive adhesive layer component) is attached to the liner on the peeled side (pre-release liner). A part of the adhesive may adhere to the adhesive sheet, causing a phenomenon in which the double-sided adhesive sheet is separated and held by both of the two liners (crying apart phenomenon). When this tearing-off phenomenon occurs, the double-faced pressure-sensitive adhesive sheet cannot be smoothly attached, and even if it is attached, the appearance may be poor (for example, Patent Document 1).

Regarding the above problems, a technique is known in which the two liners have different peel strengths from the pressure-sensitive adhesive sheet. According to this technique, when one liner is peeled off, the double-sided pressure-sensitive adhesive sheet is held on the side of the liner with high peeling strength, thereby preventing the tearing apart phenomenon.

On the other hand, double-sided adhesive sheets may require removability. The removability may be imparted to only one surface of the double-sided PSA sheet, or may be imparted to both surfaces so that it can be developed at different timings. For example, as a PSA sheet that can be preferably used as a temporary fixing material in the processing of electronic parts, etc., a double-sided PSA sheet is known in which one side loses its adhesiveness due to an external stimulus (e.g., heating, ultraviolet irradiation, etc.). ing. Such a double-faced pressure-sensitive adhesive sheet has a surface that loses adhesiveness due to an external stimulus on the workbench side, and an adherend such as an electronic component is placed on the other surface, and the adherend is processed, etc., and then It can be used in such a way that the double-sided pressure-sensitive adhesive sheet is peeled off from the workbench by an external stimulus. In this way, the electronic component can be supplied to the next step while being fixed to the adhesive sheet.

As a representative example of the double-sided pressure-sensitive adhesive sheet having removability as described above, in a double-sided pressure-sensitive adhesive sheet having different adhesion and/or peeling mechanisms on both sides, the side to be attached has a rear end and is arranged on both sides. The order of release of the liners to be applied may be specified. In such cases, the liner placed on the side to be adhered first needs to be released with a lower release force than the other liner. However, in the above-mentioned "technique for providing a difference in release force between the two liners to the pressure-sensitive adhesive sheet", the liner placed on the surface to be adhered first is not necessarily configured to be released with a low release force. However, there are cases where the technology cannot be effectively applied.

Japanese Patent Application Laid-Open No. 2003-201452

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a double-sided pressure-sensitive adhesive sheet having liners on both sides, wherein even if either liner is peeled off first, one To provide a liner-attached double-sided pressure-sensitive adhesive sheet in which the double-sided pressure-sensitive adhesive sheet remains only on the liner.

The liner-attached double-sided pressure-sensitive adhesive sheet of the present invention comprises a double-sided pressure-sensitive adhesive sheet, a first liner releasably arranged directly on one side of the double-sided pressure-sensitive adhesive sheet, and a releasable first liner on the other side of the double-sided pressure-sensitive adhesive sheet. and a second liner directly disposed on the double-sided pressure-sensitive adhesive sheet, wherein the double-sided pressure-sensitive adhesive sheet includes a first pressure-sensitive adhesive layer disposed so as to be in contact with the first liner; One pressure-sensitive adhesive layer contains heat-expandable microspheres, the peel force of the first liner to the double-sided pressure-sensitive adhesive sheet is 0.001 N/50 mm to 2 N/50 mm, and the thickness of the first liner is 3 The product (I) of the first power and the elastic modulus of the first liner is 1×10 ⁻⁷ to 1×10 ⁻² (N/m), and the cube of the thickness of the second liner; The product (II) with the elastic modulus of the second liner is 1×10 ⁻⁷ to 1×10 ⁻² (N/m), and the cube of the thickness of the first liner and the thickness of the first The product (I) of the elastic modulus of the liner, the product (II) of the cube of the thickness of the second liner and the elastic modulus of the second liner, and a single layer of each layer constituting the double-sided pressure-sensitive adhesive sheet The sum of all layers (III), which is the product of the cube of the thickness and the single-layer elastic modulus, satisfies the following relationships (1) and (2).
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 the first pressure-sensitive adhesive layer, a substrate, and a second pressure-sensitive adhesive layer in this order.
In one embodiment, the sum of all layers (III) 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 is 1×10 ⁻⁶ Nm to 1×10 ^{− 1} Nm.
In one embodiment, the product (I) of the cube of the thickness of the first liner and the modulus of elasticity of the first liner, the cube of the thickness of the second liner and the second liner The product (II) of the elastic modulus and the total (III) of the product of the single layer thickness cubed and the single layer elastic modulus of each layer constituting the double-sided pressure-sensitive adhesive sheet has the following relationship (3): meet.
0.001≦{(I)+(II)}/(III)≦1500 (3)
In one embodiment, the Si—Kα ray intensity of the first liner and/or the second liner by fluorescent X-ray analysis is 0.01 to 500 kcps.
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 thickness of the first liner and/or the second liner is 10 μm to 100 μm.
In one embodiment, the thickness of the first liner and the thickness of the second liner are different.
In one embodiment, the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer contain an acrylic pressure-sensitive adhesive.
In one embodiment, the acrylic pressure-sensitive adhesive contains an acrylic polymer containing a structural unit derived from a monomer having an active hydrogen group.
In one embodiment, the content of the structural unit derived from the monomer having an active hydrogen group is 0.1% by weight to 20% by weight based on the total structural units constituting the acrylic polymer.
In one embodiment, the absolute value of the difference between the peel strength of the first liner to the double-sided pressure-sensitive adhesive sheet and the peel strength of the second liner to the double-sided pressure-sensitive adhesive sheet is 0.5 N/50 mm or less.
In one embodiment, the liner-attached double-sided pressure-sensitive adhesive sheet is roll-shaped.
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 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 pressure-sensitive adhesive sheet is used for processing including the step of peeling off the second liner first.

According to the present invention, it is possible to provide a double-sided pressure-sensitive adhesive sheet with a liner, which is a double-sided pressure-sensitive adhesive sheet having liners on both sides, wherein the double-sided pressure-sensitive adhesive sheet remains on only one liner even if either liner is peeled off first. can.

1 is a schematic cross-sectional view of a liner-attached double-sided pressure-sensitive adhesive sheet according to one embodiment of the present invention; FIG. It is a top view explaining liner peeling operability evaluation b in an example.

A. Outline of liner-attached double-sided pressure-sensitive adhesive sheet FIG. 1 is a schematic cross-sectional view of a liner-attached double-sided pressure-sensitive adhesive sheet according to one embodiment of the present invention. The liner-attached double-sided pressure-sensitive adhesive sheet 100 consists of a double-sided pressure-sensitive adhesive sheet 10, a first liner 20 releasably arranged directly on one side of the double-sided pressure-sensitive adhesive sheet 10, and a releasable first liner 20 on the other side of the double-sided pressure-sensitive adhesive sheet 10. and a second liner 30 disposed directly on the . By arranging the first liner 20 and the second liner 30, it is possible to protect the pressure-sensitive adhesive layer from contamination, etc., and prevent blocking of the roll-shaped or sheet-shaped double-sided pressure-sensitive adhesive sheet.

The double-sided 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 placed in contact with the first liner 20 . The first adhesive layer 11 contains thermally expandable microspheres. When the pressure-sensitive adhesive layer containing heat-expandable microspheres is heated, the heat-expandable microspheres expand or foam to form irregularities on the pressure-sensitive adhesive surface, resulting in reduced or lost adhesive strength. The double-sided pressure-sensitive adhesive sheet 10 having such a pressure-sensitive adhesive layer 11 can be easily peeled off by heating.

The double-sided pressure-sensitive adhesive sheet may be a single layer (that is, it may be configured to include only the first pressure-sensitive adhesive layer), or it may be a laminate composed of multiple layers. In one embodiment, as shown in FIG. 1, double-sided pressure-sensitive adhesive sheet 10 comprises first pressure-sensitive adhesive layer 11, substrate 12, and second pressure-sensitive adhesive layer 13 in this order. With such a configuration, various pressure-sensitive adhesives can be used, and various means such as extrusion, coating, and coating can be selected as a method for forming the pressure-sensitive adhesive layer, which is useful.

The peel force of the first liner and the second liner to the double-sided pressure-sensitive adhesive sheet is 0.001N/50mm to 2N/50mm. In addition, the first liner has a product (I) of the cube of the thickness and the elastic modulus of the first liner is 1×10 ⁻⁷ to 1×10 ⁻² (N/m). Also, the second liner has a product (II) of the third power of the thickness and the elastic modulus of the second liner is 1×10 ⁻⁷ to 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, and the product of the cube of the thickness of the second liner and the elastic modulus of the second liner ( II) and (III), the sum of all layers, which is 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)

According to the present invention, by focusing on the characteristics of the liners and constructing them as described above, even if either liner is peeled off first, the double-sided PSA sheet remains only on one liner. It is possible to provide a liner-equipped double-sided pressure-sensitive adhesive sheet that is prevented from being detached. The present invention has excellent liner peeling operability, and (i) the edge of the liner (preliminary release liner) is easy to pick up (easy to catch); (iii) the folding angle of the liner during liner peeling (preferably 90° to 180°, more preferably 120° to 180°, even more preferably 135° to 180°, more preferably 150° to 180°, especially preferably 165° to 180°) is less likely to fluctuate during the stripping operation; When the liner is peeled off in this manner, the force (peeling stress) exerted by the peeling operation concentrates on the peeling portion of the release liner (the portion where the liner peeled from the adhesive layer contacts the adhesive layer). As a result, the force required for peeling can be reduced, preventing tearing of the pressure-sensitive adhesive layer at the peeling portion and poor peeling of the liner requiring peeling, etc., leaving the double-sided pressure-sensitive adhesive sheet on only one liner.

In general, an adhesive layer containing heat-expandable microspheres may have ridges on the surface, and when peeling off the liner, the peeling stress tends to be difficult to concentrate. The liner-equipped double-sided pressure-sensitive adhesive sheet of the present invention, which has the above effects while having an agent layer, is useful.

The above "(I) / {(II) + (III)}" is preferably 0.0035 to 250, more preferably 0.0035 to 150, still more preferably 0.0035 to 100, Especially preferably, it is 0.0035 to 30. The above "(II)/{(I)+(III)}" is preferably 0.003 to 500, more preferably 0.0035 to 300, still more preferably 0.0035 to 150, Especially preferred is 0.0035 to 130. With such a range, the above effect becomes remarkable. In addition, "the total of all layers (III) of the product of the single layer thickness cubed and the single layer elastic modulus of each layer constituting the double-sided pressure-sensitive adhesive sheet" is the single-layer thickness of each layer constituting the double-sided pressure-sensitive adhesive sheet. It is a value obtained by obtaining the product (x1, x2, . For example, when the double-sided pressure-sensitive adhesive sheet includes a first pressure-sensitive adhesive layer, a substrate, and a second pressure-sensitive adhesive layer, the cube of the thickness of the first pressure-sensitive adhesive layer and the elasticity of the first pressure-sensitive adhesive layer the product of the modulus (x1), the product of the cube of the thickness of the substrate and the elastic modulus of the substrate (x2), the cube of the thickness of the second adhesive layer and the elastic modulus of the second adhesive layer and the sum (x1+x2+x3) of the product (x3) corresponds to "all layer sum (III) of the product of the single layer thickness cubed and the single layer elastic modulus of each layer constituting the double-sided PSA sheet". Further, when the double-sided pressure-sensitive adhesive sheet includes a first pressure-sensitive adhesive layer, an undercoat layer, a base material, and a second pressure-sensitive adhesive layer, the cube of the thickness of the first pressure-sensitive adhesive layer and the first pressure-sensitive adhesive layer The product of the elastic modulus of the agent layer (x1), the product of the cube of the thickness of the undercoat layer and the elastic modulus of the undercoat layer (x2), and the product of the cube of the thickness of the substrate and the elastic modulus of the substrate (x3). 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 (x1+x2+x3+x4) is the "single layer thickness of each layer constituting the double-sided pressure-sensitive adhesive sheet. It corresponds to the sum of all layers (III) of the product of the 3rd power and the single layer elastic modulus.

In one embodiment, the product (I) of the cube of the thickness of the first liner and the modulus of the first liner and the cube of the thickness of the second liner and the elasticity of the second liner The product (II) with the modulus and the sum (III) of the product of the single-layer elastic modulus and the cube of the single-layer thickness of each layer constituting the double-sided PSA sheet satisfy the following relationship (3).
0.001≦{(I)+(II)}/(III)≦1500 (3)
With such a 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 less likely to buckle during cutting. Such an effect is particularly useful in a double-sided pressure-sensitive adhesive sheet provided with a first pressure-sensitive adhesive layer containing heat-expandable microspheres. {(I)+(II)}/(III) is more preferably 0.005 to 1000, still more preferably 0.015 to 500, particularly preferably 0.015 to 300, most preferably 0.015 ~250.

In one embodiment, when using the liner-attached double-sided pressure-sensitive adhesive sheet, the second liner is removed first. More specifically, the liner-equipped double-sided pressure-sensitive adhesive sheet is prepared by first peeling off the second liner and attaching an adherend (for example, an electronic component) to the exposed pressure-sensitive adhesive surface (for example, the surface of the second pressure-sensitive adhesive layer). It can be used by sticking, then peeling off the first liner, and sticking the surface of the first pressure-sensitive adhesive layer on another adherend (for example, a pedestal). In such an embodiment, the adherend (e.g., electronic component) is temporarily fixed to the pedestal via the double-sided adhesive sheet; the adherend is subjected to a predetermined process; The double-sided pressure-sensitive adhesive sheet attached to the adherend is peeled off from the pedestal.

B. First Liner, Second Liner Typically, the first liner and the second liner each comprise 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 arranged so that the release treated layer is on the double-sided pressure-sensitive adhesive sheet side. In addition, the first liner and the second liner may have the same configuration, or may have different configurations.

As described above, the peel force of the first liner to the double-sided adhesive sheet is 0.001N/50mm to 2N/50mm. The peel strength of the first liner to the double-sided pressure-sensitive adhesive sheet is preferably 0.01N/50mm to 1.5N/50mm, more preferably 0.05N/50mm to 1N/50mm, and particularly preferably 0.1N. /50 mm to 0.8 N/50 mm. By setting the release force of the liner to the double-sided pressure-sensitive adhesive sheet within the above range, the liner is not unnecessarily peeled off, and it is possible to quickly pick up the end surface when the liner is peeled off, and the first pressure-sensitive adhesive layer is formed. It is possible to prevent the heat-expandable microspheres from coming off. The release force of the first liner to the double-sided pressure-sensitive adhesive sheet (and the release force of the second liner to the double-sided pressure-sensitive adhesive sheet) was measured in an environment of 23°C. (Peeling angle: 180°, peeling speed (tensile speed): 300 mm/min) means the adhesive force measured. The release force of the liner to the double-sided PSA sheet can be adjusted by any appropriate method, such as the composition of the PSA layer, the type of liner, and the surface treatment applied to the liner.

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

The release force of the first liner to the double-sided pressure-sensitive adhesive sheet and the release force of the second liner to the double-sided pressure-sensitive adhesive sheet may be the same or different. In one embodiment, the absolute value of the difference between the peel force of the first liner to the double-sided pressure-sensitive adhesive sheet and the peel force of the second liner to the double-sided pressure-sensitive adhesive sheet is preferably 0.5 N/50 mm or less, and more It is preferably 0.4 N/50 mm or less, more preferably 0.2 N/50 mm or less. According to the present invention, even if either liner is peeled off first, the double-sided pressure-sensitive adhesive sheet can remain on only one liner without providing a difference in peel strength between the first liner and the second liner. A double-sided pressure-sensitive adhesive sheet can be obtained.

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, most preferably 30 to 100 μm. Within such a range, the liner can be excellent in distinguishability and can easily maintain the peeling angle (turning angle) during peeling. In addition, it is possible to obtain a liner that is easy to wind when wound on a roll and that prevents the problem of the liner separating from the pressure-sensitive adhesive layer during punching (so-called "floating"). In one embodiment, the first liner has a thickness of 10 μm to 100 μm.

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

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. Using liners of different thickness makes it easier to identify the liner to be removed.

The elastic modulus of the first liner (substantially the liner base material) is 500 MPa to 5000 MPa, more preferably 500 MPa to 4000 MPa, still more preferably 700 MPa to 4000 MPa. Within such a range, it is possible to obtain a liner that is excellent in operability, is easy to wind when wound on a roll, and prevents the problem that the liner separates from the adhesive layer during punching (so-called "floating"). can. In the specification, the elastic modulus means the elastic modulus measured by the nanoindentation method in a 23° C. environment. The elastic modulus by the nanoindentation method is obtained by continuously measuring the load applied to the indenter and the indentation depth during loading and unloading when the indenter is pushed into the sample (which may be a liner base material). It refers to the modulus of elasticity obtained from the obtained applied load-indentation depth curve. The conditions for measuring the elastic modulus by the nanoindentation method will be described later.

The elastic modulus of the second liner (substantially the liner base material) is 500 MPa to 5000 MPa, more preferably 500 MPa to 4000 MPa, still more preferably 700 MPa to 4000 MPa. The modulus of elasticity of the first liner and the modulus of elasticity of the second liner may be the same or different.

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 to 1×10 ⁻² (N/m). The product (I) is preferably 1×10 ⁻⁶ to 5×10 ⁻³ (N/m), more preferably 5×10 ⁻⁶ to 2×10 ⁻³ (N/m). Within such a range, it is possible to obtain a liner that is easy to fold back and that can easily maintain the peeling angle (folding angle) during peeling.

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 to 1×10 ⁻² (N/m). The product (II) is preferably 1×10 ⁻⁶ to 5×10 ⁻³ (N/m), more preferably 5×10 ⁻⁶ to 2×10 ⁻³ (N/m), particularly preferably is 5×10 ⁻⁶ to 1.5×10 ⁻³ (N/m), most preferably 5×10 ⁻⁶ to 1.308×10 ⁻³ . Within such a range, it is possible to obtain a liner that is easy to fold back and that can easily maintain the peel angle (fold angle) during peeling. The "product (I)" of the first liner and the "product (II)" of the second liner may be the same or different.

The liner base material can be composed of any appropriate material. As the liner base material, for example, in addition to plastic films and plastic sheets, 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 for the plastic film can be selected according to need from the viewpoint of strength, heat resistance, and the like. For example, polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA) and other α-olefin-based resins as monomer components; polyethylene terephthalate (PET), polyethylene Polyesters such as naphthalate (PEN) and polybutylene terephthalate (PBT); polyvinyl chloride (PVC); polyphenylene sulfide (PPS); amide resins such as polyamide (nylon) and wholly aromatic polyamide (aramid); Ketone (PEEK), polyimide, polyetherimide, polystyrene, acrylic resin and the like. These materials can be used alone or in combination of two or more. Moreover, as the plastic film, any of an unstretched film, a uniaxially oriented film, and a biaxially oriented film may be used. In addition, these films may be laminated films composed of two or more film layers, or films to which a lubricant such as inert particles is appropriately added may be used from the viewpoint of handleability.

Any appropriate treatment can be adopted as the treatment for forming the release treatment layer. In one embodiment, the release treated layer is a silicone treated layer. As the silicone, a reactive silicone compound containing a dimethylpolysiloxane as a main component and having a functional group necessary for cross-linking (curing) can 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 treated layer that is resistant to rubbing and the like. Examples of functional groups of reactive silicone compounds include vinyl groups, epoxy groups, alkoxy groups, isocyanato groups, and the like.

The silicone-treated layer is formed, for example, by diluting the above-mentioned reactive silicone compound with a solvent or the like to adjust the concentration, and applying and heating with a gravure coater or the like. Heating accelerates solvent drying and curing reactions. Here, it is preferable to use a catalyst that accelerates the curing reaction. Examples of catalysts that can be used include metal complexes such as platinum, palladium, rhodium, zirconium and tin, organic bases such as amines, and organic acids such as acetic acid.

In one embodiment, the first liner and/or the second liner (substantially the release treatment layer of each liner) has a Si—Kα ray intensity of 0.01 by fluorescent X-ray analysis. ~500 kcps (preferably 0.5 to 250 kcps, more preferably 1.0 to 150 kcps, still more preferably 1.05 to 100 kcps). Within such a range, the liner can be peeled off from the pressure-sensitive adhesive layer with a small force, making it easy to quickly pick up one end of the liner by a small amount. In addition, the adhesion between the liner and the adhesive layer is sufficient, and unnecessary peeling of the liner can be prevented. The intensity of the Si-Kα ray obtained by the above fluorescent X-ray analysis is obtained by measuring the Si intensity of the release agent layer and the non-release agent layer by the fluorescence X-ray analysis, and calculating the intensity of the release agent layer from the intensity of the non-release agent. It is a value obtained by reducing the strength of the layer. The strength can be adjusted by controlling the release treatment layer forming conditions such as the coating amount, concentration, coating speed and drying of the release treatment agent.

In one embodiment, the first liner and the second liner are different colors. A liner-equipped double-sided pressure-sensitive adhesive sheet having such a structure can be obtained, for example, by coloring one of the liners (for example, the liner substrate). If both liners are of different colors, the front and back of the liner-attached double-sided pressure-sensitive adhesive sheet can be clearly distinguished, making it easy to identify the liner to be peeled off.

C. Double-Sided Adhesive Sheet As described above, the double-sided adhesive sheet has a first adhesive layer. In one embodiment, the double-sided PSA sheet comprises a first PSA layer, a substrate, and a second PSA layer in this order. In one embodiment, the double-sided PSA sheet further comprises a primer layer disposed between the first PSA layer and the substrate. A double-faced pressure-sensitive adhesive sheet having excellent conformability to adherends can be obtained by providing an undercoat layer. When the first pressure-sensitive adhesive layer containing heat-expandable microspheres is heated, the heat-expandable microspheres expand and deform due to expansion in the thickness direction. is suppressed, so the releasability is improved.

The initial adhesive force at 23° C. when the first adhesive layer of the double-sided PSA 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, more preferably 0.5 N/20 mm to 15 N/20 mm. Within such a range, for example, a double-sided pressure-sensitive adhesive sheet useful as a temporary fixing sheet used in the manufacture of electronic components can be obtained. In the present specification, the initial adhesive strength is the adhesive strength in a state where the adhesive strength has not decreased due to the expansion of the heat-expandable microspheres, and means the adhesive strength in the state where the heat history of 50° C. or more has not been passed. . In addition, the adhesive strength refers to the adhesive strength measured by a method according to JIS Z 0237:2000 (bonding conditions: one reciprocation of a 2 kg roller, peeling speed: 300 mm/min, peeling angle of 180°).

When the first pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet is adhered to polyethylene terephthalate, the pressure-sensitive adhesive strength 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.

The adhesive force 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 more preferably 0.5 N/20 mm to 15 N/20 mm.

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

The sum of all layers (III) of the product of the single layer thickness cubed and the single layer elastic modulus of each layer constituting the double-sided pressure-sensitive adhesive sheet is preferably 1×10 ⁻⁶ Nm to 1×10 ⁻¹ Nm, It is more preferably 5×10 ⁻⁶ Nm to 5×10 ⁻² and even more preferably 5×10 ⁻⁶ Nm to 3×10 ⁻² . Within such a range, it is possible to obtain a double-sided pressure-sensitive adhesive sheet that is highly self-supporting, has excellent lamination operability, and has excellent flexibility. Such an effect is particularly useful in a double-sided pressure-sensitive adhesive sheet provided with a first pressure-sensitive adhesive layer containing heat-expandable microspheres.

In one embodiment, at least one of the layers constituting the double-sided pressure-sensitive adhesive sheet is a colored layer. When a plurality of colored layers exist, it is preferable that each layer has a different color. With these configurations, the front and back sides of the liner-attached double-sided pressure-sensitive adhesive sheet become clear, making it easy to identify the liner to be peeled off. Coloring means a state of absorbing and/or reflecting any or all light in the visible region (250 nm to 700 nm). Any appropriate method can be adopted as a method for coloring any one layer.

A pigment, a dye, or the like can be used as the coloring agent. Examples of the pigment include organic pigments such as acrylic pigments, azo pigments, polyazo pigments, anthraquinone pigments, quinacridone pigments, isoindoline pigments, isoindolinone pigments, phthalocyanine pigments, perylene pigments, and DPP pigments. Pigments, fluorescent pigments, condensed polycyclic pigments, colored resin particles, etc., and inorganic pigments include known pigments such as carbon black, synthetic silica, chromium oxide, iron oxide, titanium oxide, zinc sulfide, calcined pigments, and natural mica. mentioned. Dyes include acid dyes, reactive dyes, direct dyes, disperse dyes, cationic dyes, polymer dyes and the like. As the ink, commercially available products such as "NB300" manufactured by Dainichiseika may be used. Coloring is also possible by mixing a coloring agent into the pressure-sensitive adhesive layer. In addition, when the composition of the pressure-sensitive adhesive layer has a fine structure with a size of about the wavelength of visible light, for example, by microphase separation between a hydrophilic composition and a hydrophobic composition, depending on the size A phenomenon of coloring, that is, a so-called structural color, may be exhibited, and coloring using this is also possible.

C-1. First Adhesive Layer The first adhesive layer contains thermally expandable microspheres as described above. The first adhesive layer may further contain an adhesive.

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

(Acrylic adhesive)
In one embodiment, an acrylic adhesive is used as the adhesive. Examples of the acrylic pressure-sensitive adhesive include, for example, an acrylic pressure-sensitive adhesive whose base polymer is an acrylic polymer (homopolymer or copolymer) using one or more of (meth)acrylic acid alkyl esters as a monomer component. etc.

Specific examples of the (meth)acrylic acid alkyl esters 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, (meth)acrylic acid Octyl, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, (meth)acrylic undecyl acid, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, (meth)acrylic acid Examples include (meth)acrylic acid C1-20 alkyl esters such as octadecyl, nonadecyl (meth)acrylate and eicosyl (meth)acrylate. Among them, (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 carbon atoms) are more preferable. is 2-ethylhexyl (meth)acrylate.

For the purpose of modifying cohesive strength, heat resistance, crosslinkability, etc., the acrylic polymer may optionally be a unit corresponding to another monomer component copolymerizable with the (meth)acrylic acid alkyl ester. may contain 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; maleic anhydride and icotanic anhydride; Acid anhydride monomers such as; hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, hydroxybutyl (meth)acrylate, hydroxyhexyl (meth)acrylate, hydroxyoctyl (meth)acrylate, (meth)acrylate Hydroxyl group-containing monomers such as hydroxydecyl acrylate, hydroxyllauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl methacrylate; styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid , (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloyloxynaphthalenesulfonic acid and other sulfonic acid group-containing monomers; (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (N-substituted) amide-based monomers such as (meth)acrylamide, N-methylol (meth)acrylamide, N-methylolpropane (meth)acrylamide; aminoethyl (meth)acrylate, N,N-dimethyl (meth)acrylate Aminoalkyl (meth)acrylate monomers such as aminoethyl and t-butylaminoethyl (meth)acrylate; Alkoxyalkyl (meth)acrylates such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate Monomers: Maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide; N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide , N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide, N-lauryl itaconimide and other itaconimide monomers; N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, Succinimide-based monomers such as N-(meth)acryloyl-8-oxyoctamethylenesuccinimide; vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone Vinyls such as lydone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides, styrene, α-methylstyrene, N-vinylcaprolactam, etc. 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, (meth)acrylic acid Glycol-based acrylic ester monomers such as methoxyethylene glycol and methoxypolypropylene glycol (meth)acrylate; heterocycles such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicone (meth)acrylate, halogen atoms, silicon atoms Acrylic acid ester monomers having such as; hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol Polyfunctional monomers such as di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate; isoprene, butadiene, Olefin monomers such as isobutylene; vinyl ether monomers such as vinyl ether; These monomer components may be used alone or in combination of two or more. Among the above, a carboxyl group-containing monomer (particularly preferably acrylic acid) or a hydroxyl group-containing monomer (particularly preferably hydroxyethyl (meth)acrylate) is more preferred. The content of structural units derived from a carboxyl group-containing monomer is preferably 0.1% by weight to 10% by weight, more preferably 0.5% by weight to 5% by weight, based on all structural units constituting the acrylic polymer. % by weight, particularly preferably 1 to 4% by weight. In addition, the content of the structural units derived from the hydroxyl group-containing monomer is preferably 0.1% by weight to 20% by weight, more preferably 0.5% by weight, based on all the structural units constituting the acrylic polymer. to 10% by weight, particularly preferably 1% to 7% by weight. In addition, in this specification, (meth)acryl means acryl and/or methacryl.

In one embodiment, the acrylic polymer contains a structural unit derived from a monomer having an active hydrogen group. By including a structural unit derived from a monomer having an active hydrogen group, the acrylic polymer undergoes microphase separation and scatters light in the visible range to be colored (milky white to pale yellow). can facilitate identification.

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

The acrylic pressure-sensitive adhesive may contain any suitable additive as necessary. The additives include, for example, cross-linking agents, tackifiers, plasticizers (e.g., trimellitic acid ester plasticizers, pyromellitic acid ester plasticizers, etc.), pigments, dyes, fillers, anti-aging agents, conductive materials, antistatic agents, ultraviolet absorbers, light stabilizers, release modifiers, softeners, surfactants, flame retardants, antioxidants, and the like.

Examples of the cross-linking agent contained in the acrylic pressure-sensitive adhesive include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, melamine-based cross-linking agents, peroxide-based cross-linking agents, urea-based cross-linking agents, metal alkoxide cross-linking agents, Examples include metal chelate cross-linking agents, metal salt cross-linking agents, carbodiimide cross-linking agents, oxazoline cross-linking agents, aziridine cross-linking agents, and amine cross-linking agents. Among them, an isocyanate-based cross-linking agent or an epoxy-based cross-linking agent is preferable.

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

Examples of the epoxy-based cross-linking agent contained in the acrylic pressure-sensitive adhesive include N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N- glycidylaminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C"), 1,6-hexanediol diglycidyl ether (manufactured by Kyoeisha Chemical Co., Ltd., trade name "Epolite 1600"), neopentyl glycol diglycidyl ether ( Kyoeisha Chemical Co., Ltd., trade name "Epolite 1500NP"), ethylene glycol diglycidyl ether (Kyoeisha Chemical Co., Ltd., trade name "Epolite 40E"), propylene glycol diglycidyl ether (Kyoeisha Chemical Co., Ltd., trade name "Epolite 70P") , polyethylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name "Epiol E-400"), polypropylene glycol diglycidyl ether (manufactured by NOF Corporation, trade name "Epiol P-200"), sorbitol polyglycidyl ether (Nagasechem Tex Corporation, trade name "Denacol EX-611"), glycerol polyglycidyl ether (Nagase ChemteX Corporation, trade name "Denacol EX-314"), pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether (Nagase ChemteX Corporation) company, product name "Denacol EX-512"), sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, diglycidyl adipate, o-diglycidyl phthalate, triglycidyl-tris(2-hydroxyethyl) isocyanate Examples include nurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, and epoxy resins having two or more epoxy groups in the molecule. The content of the epoxy-based cross-linking agent can be set to any appropriate amount depending on the desired adhesive strength, and is typically 0.01 to 10 parts by weight with respect to 100 parts by weight of the base polymer. and more preferably 0.03 to 5 parts by weight.

Any appropriate tackifier is used as the tackifier contained in the acrylic pressure-sensitive adhesive. As the tackifier, for example, a tackifier resin is used. Specific examples of the tackifying resin include rosin-based tackifying resins (e.g., unmodified rosin, modified rosin, rosin phenol-based resin, rosin ester-based resin, etc.), terpene-based tackifying resins (e.g., terpene-based resin, terpene phenolic resin, styrene-modified terpene-based resin, aromatic-modified terpene-based resin, hydrogenated terpene-based resin), hydrocarbon-based tackifying resin (e.g., aliphatic hydrocarbon resin, aliphatic cyclic hydrocarbon resin, aromatic Hydrocarbon resins (e.g., styrene resins, xylene resins, etc.), aliphatic/aromatic petroleum resins, aliphatic/alicyclic petroleum resins, hydrogenated hydrocarbon resins, coumarone resins, coumarone-indene resins resins, etc.), phenolic tackifying resins (e.g., alkylphenolic resins, xylene-formaldehyde-based resins, resols, novolacs, etc.), ketone-based tackifying resins, polyamide-based tackifying resins, epoxy-based tackifying resins, elastomer-based tackifying resins etc. Among them, rosin-based tackifying resins, terpene-based tackifying resins, and hydrocarbon-based tackifying resins (styrene-based resins, etc.) are preferred. A tackifier 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, relative to 100 parts by weight of the base polymer.

(Heat-expandable microspheres)
Any appropriate heat-expandable microspheres can be used as the heat-expandable microspheres as long as they can be expanded or foamed by heating. As the heat-expandable microspheres, for example, microspheres in which a substance that easily expands by heating is encapsulated in an elastic shell can be used. Such heat-expandable microspheres can be produced by any appropriate method such as coacervation, interfacial polymerization, and the like.

Substances that easily expand when heated include, for example, propane, propylene, butene, normal butane, isobutane, isopentane, neopentane, normal pentane, normal hexane, isohexane, heptane, octane, petroleum ether, methane halides, and tetraalkylsilanes. low boiling point liquid such as; azodicarbonamide gasified by thermal decomposition; and the like.

Examples of substances constituting the shell include nitrile monomers such as acrylonitrile, methacrylonitrile, α-chloroacrylonitrile, α-ethoxyacrylonitrile, and fumaronitrile; acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, Carboxylic acid monomers such as citraconic acid; vinylidene chloride; vinyl acetate; methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, (Meth)acrylic acid esters such as isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, β-carboxyethyl acrylate; styrene monomers such as styrene, α-methylstyrene, chlorostyrene; acrylamide, substituted acrylamide , methacrylamide, substituted methacrylamide, and other amide monomers; A polymer composed of these monomers may be a homopolymer or a copolymer. Examples of the copolymer include vinylidene chloride-methyl methacrylate-acrylonitrile copolymer, methyl methacrylate-acrylonitrile-methacrylonitrile copolymer, methyl methacrylate-acrylonitrile copolymer, acrylonitrile-methacrylonitrile-itaconic acid copolymer, A polymer etc. are mentioned.

An inorganic foaming agent or an organic foaming agent may be used as the thermally expandable microspheres. Examples of inorganic foaming agents include ammonium carbonate, ammonium hydrogencarbonate, sodium hydrogencarbonate, ammonium nitrite, sodium borohydride, and various azides. Examples of organic foaming agents include chlorofluoroalkane compounds such as trichloromonofluoromethane and dichloromonofluoromethane; and azo compounds such as azobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate. hydrazine compounds such as paratoluenesulfonyl hydrazide, diphenylsulfone-3,3′-disulfonyl hydrazide, 4,4′-oxybis(benzenesulfonyl hydrazide), and allylbis(sulfonyl hydrazide); p-toluylenesulfonyl semicarbazide, 4, Semicarbazide compounds such as 4'-oxybis(benzenesulfonyl semicarbazide); triazole compounds such as 5-morpholyl-1,2,3,4-thiatriazole; N,N'-dinitrosopentamethylenetetramine, N,N' -dimethyl-N,N'-dinitrosoterephthalamide; and other N-nitroso compounds.

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, even more preferably 10 μm to 20 μm, and particularly preferably 10 μm to 15 μm. . Therefore, the average particle size of the heat-expandable microspheres before heating is preferably 6 μm to 45 μm, more preferably 15 μm to 35 μm. The above particle size and average particle size are values determined by a particle size distribution measurement method in a laser scattering method.

It is preferable that the thermally expandable microspheres have an appropriate strength such that they do not burst until the volume expansion coefficient is preferably 5 times or more, more preferably 7 times or more, and still more preferably 10 times or more. When such heat-expandable microspheres are used, the adhesive strength can be efficiently reduced by heat treatment.

The content of the heat-expandable microspheres in the pressure-sensitive adhesive layer can be appropriately set according to the desired decrease in adhesive force. The content of the thermally expandable microspheres is, for example, 1 part by weight to 150 parts by weight, preferably 10 parts by weight to 130 parts by weight, more preferably 100 parts by weight of the base polymer forming the pressure-sensitive adhesive layer. is 25 to 100 parts by weight.

The arithmetic surface roughness Ra of the first adhesive layer before the thermally expandable microspheres are expanded (that is, before heating) is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less. is. In the pressure-sensitive adhesive layer containing heat-expandable microspheres, ridges caused by the heat-expandable microspheres may occur, but if the surface roughness before heating is within the above range, the peel stress during liner peeling will rise. It is possible to obtain a double-sided pressure-sensitive adhesive sheet that allows liner peeling without causing troubles such as partial tearing of the pressure-sensitive adhesive layer or tearing-off phenomenon, and that has excellent adhesion to the adherend. The arithmetic surface roughness Ra is, for example, the thickness of the first pressure-sensitive adhesive layer, the surface smoothness of the substrate when the first pressure-sensitive adhesive layer formed on the substrate is transferred to form a double-sided pressure-sensitive adhesive sheet, the first It can be adjusted by the drying conditions and the like during the formation of the pressure-sensitive adhesive layer.

The thickness of the first 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 such a range, it is possible to obtain a double-faced PSA sheet that is excellent in liner peeling operability, operability in adhesion, adhesiveness, smoothness, and deformability in heating. In one embodiment, the thickness of the first adhesive layer is 23 μm to 47 μm. Within this range, from the viewpoint of the smoothness of the adhesive layer surface, a double-sided PSA sheet that is particularly suitable when the adherend is a pedestal substrate used for CSP or WLP can be obtained.

The elastic modulus of the first adhesive layer is preferably 0.001 MPa to 10 MPa, more preferably 0.01 MPa to 8 MPa. Within such a range, it is possible to obtain a double-faced PSA sheet that is excellent in liner peeling operability, operability in adhesion, adhesiveness, smoothness, and deformability in heating. In one embodiment, the elastic modulus of the first adhesive layer is preferably 0.05 MPa to 4 MPa, more preferably 0.1 MPa to 3 MPa. Within this range, from the viewpoint of the smoothness of the adhesive layer surface, a double-sided PSA sheet that is particularly suitable when the adherend is a pedestal substrate used for CSP or WLP can be obtained.

C-2. Second Adhesive Layer The second adhesive layer may contain any appropriate adhesive. Examples of the adhesive that constitutes the second adhesive layer include acrylic adhesives, rubber adhesives, silicone adhesives, and the like. Among them, an acrylic pressure-sensitive adhesive can be preferably used. As the adhesive, an active energy ray-curable acrylic adhesive (hereinafter referred to as an active energy ray-curable adhesive) may be used. Details of the adhesive are described, for example, in JP-A-2015-168711. The description of the publication is incorporated herein by reference.

In one embodiment, the second adhesive layer contains the acrylic adhesive described in section C-1. As described above, acrylic pressure-sensitive adhesives contain an acrylic polymer as a base polymer. In one embodiment, the acrylic polymer contains a structural unit derived from a monomer having an active hydrogen group. The content of the structural unit derived from the monomer having an active hydrogen group is preferably 0.1% by weight to 20% by weight, more preferably 0.5% by weight, based on the total structural units constituting the acrylic polymer. % to 10% by weight, particularly preferably 1% to 7% by weight.

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

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

C-3. Undercoat Layer The undercoat layer contains any suitable adhesive. Examples of the adhesive that constitutes the undercoat layer include acrylic adhesives, rubber adhesives, silicone adhesives, and the like. Among them, an acrylic pressure-sensitive adhesive can be preferably used. As the adhesive, an active energy ray-curable acrylic adhesive (hereinafter referred to as an active energy ray-curable adhesive) may be used. Preferably, the same pressure-sensitive adhesive as the pressure-sensitive adhesive forming the first pressure-sensitive adhesive layer is used as the pressure-sensitive adhesive forming the undercoat layer.

The thickness of the undercoat layer is preferably 1 μm to 40 μm, more preferably 5 μm to 35 μm, still more preferably 10 μm to 30 μm. Within such a range, it is possible to obtain a double-sided pressure-sensitive adhesive sheet which is excellent in liner peeling operability and in which the effect of heating the thermally expandable microspheres on the substrate side is suppressed.

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 a range, it is possible to obtain a double-sided pressure-sensitive adhesive sheet which is excellent in liner peeling operability and in which the effect of heating the thermally expandable microspheres on the substrate side is suppressed. In addition, when the undercoat layer contains an active energy ray-curable pressure-sensitive adhesive, the undercoat layer is cured by irradiation with an active energy ray, and its elastic modulus is preferably 1 MPa to 200 MPa, and 5 MPa to 150 MPa. is more preferable, and 10 MPa to 100 MPa is even more preferable.

C-4. Substrate The substrate may be composed of any suitable material. Various sheet materials such as plastic film, plastic sheet, paper, cloth, nonwoven fabric, metal foil, a plastic laminate thereof, and a laminate of plastics can be used as the base material. 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 for the plastic film can be selected according to need from the viewpoint of strength, heat resistance, and the like. For example, polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA) and other α-olefin-based resins as monomer components; polyethylene terephthalate (PET), polyethylene Polyesters such as naphthalate (PEN) and polybutylene terephthalate (PBT); polyvinyl chloride (PVC); polyphenylene sulfide (PPS); amide resins such as polyamide (nylon) and wholly aromatic polyamide (aramid); Ketone (PEEK), polyimide, polyetherimide, polystyrene, acrylic resin and the like. These materials can be used alone or in combination of two or more. Moreover, as the plastic film, any of an unstretched film, a uniaxially oriented film, and a biaxially oriented film may be used. In addition, these films may be laminated films composed of two or more film layers, or films to which a lubricant such as inert particles is appropriately added may be used from the viewpoint of handleability.

The thickness of the substrate is preferably 200 μm or less, more preferably 1 μm to 200 μm, still more preferably 5 μm to 200 μm, particularly preferably 10 μm to 200 μm, particularly preferably 20 μm to 200 μm, Most preferred is 30 μm to 200 μm. Within such a range, it is possible to contribute to improvement in liner releasability, and to obtain a base material excellent in strength, flexibility, flexibility, buckling resistance, and the like.

The elastic modulus of the base material is preferably 500 MPa to 5000 MPa, more preferably 500 MPa to 4000 MPa, still more preferably 700 MPa to 4000 MPa. Within such a range, it is possible to contribute to improvement in liner releasability, and to obtain a base material excellent in strength, flexibility, flexibility, buckling resistance, and the like.

The base material may be surface-treated. Examples of surface treatment include corona treatment, chromic acid treatment, ozone exposure, flame exposure, high voltage shock exposure, ionizing radiation treatment, and coating treatment with a primer.

The substrate may be printed with ink or the like in order to enhance the liner edge recognition and to enhance the anchoring property between the substrate and the adhesive layer. As the ink, "NB300" manufactured by Dainichi Seika Co., Ltd. can be used.

C-5. Method for producing double-sided PSA sheet The double-sided PSA sheet can be produced by any appropriate method. The method for producing the double-sided PSA sheet of the present invention includes, for example, a method of directly coating a substrate with a composition containing an adhesive, or a method of coating a composition containing an adhesive on any appropriate substrate. Examples include a method of transferring the formed coating layer to the base material. In addition, a laminate (first liner/first adhesive layer, second adhesive layer/second liner) formed by coating a composition containing an adhesive on a liner is used as a base material. A liner-attached double-sided pressure-sensitive adhesive sheet may be obtained by a lamination method. A composition containing an adhesive may contain any suitable solvent.

The first adhesive layer can be formed by coating a substrate with a composition containing thermally expandable microspheres, an adhesive, and any suitable solvent. Alternatively, after sprinkling heat-expandable microspheres on the adhesive coating layer, the heat-expandable microspheres are embedded in the adhesive using a laminator or the like to form an adhesive layer containing the heat-expandable microspheres. may be formed.

When the double-sided pressure-sensitive adhesive sheet has the undercoat layer, the undercoat layer is formed, for example, by applying a composition (adhesive) for forming the undercoat layer onto the substrate or onto the first pressure-sensitive adhesive layer. can do.

Any appropriate coating method can be adopted as the coating method for the 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, die coater, gravure coater, applicator, and the like. Drying methods include, for example, natural drying and heat drying. The heating temperature for drying by heating can be set to any suitable temperature depending on the properties of the substance to be dried.

D. Uses The liner-attached double-sided pressure-sensitive adhesive sheet can be preferably used as a temporary fixing sheet when processing any appropriate member (for example, electronic parts 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 during the manufacture of CSP (Chip Size/Scale Package) or WLP (Wafer Level Package). In one embodiment, the liner-attached double-sided pressure-sensitive adhesive sheet is used for processing including the step of peeling off the second liner first.

In one embodiment, the liner-attached double-sided pressure-sensitive adhesive sheet is roll-shaped.

The present invention will be specifically described 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.

[Production Example 1] Production of liner a (thickness: 12 μm) Addition-type silicone treatment agent (manufactured by Shin-Etsu Silicone Co., Ltd., 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 (mixed weight ratio: 1:1) to prepare a stripping agent solution adjusted to a concentration of 0.9%.
Next, one surface of a PET film (manufactured by Toray Industries, Inc., trade name “Lumirror S10”, thickness 12 μm) is coated with the above-described release treatment agent solution using a gravure method, dried using a hot air oven, and the thickness A 12 μm liner a was obtained. The Si-Kα ray intensity of the obtained liner was 13 (kcps) (the measuring method will be described later).

[Production Example 2] Production of liner b (thickness: 75 μm) In the same manner as in Production Example 1, except that a 75 μm thick PET film (manufactured by Toray Industries, Inc., trade name “Lumirror S10”) was used as the PET film. A liner b having a thickness of 75 μm was obtained. The Si-Kα ray intensity of the obtained liner was 80 (kcps).

[Production Example 3] Production of liner c (thickness: 38 µm) In the same manner as in Production Example 1, A liner c having a thickness of 38 μm was obtained. The Si-Kα ray intensity of the resulting liner was 3.2 (kcps).

[Production Example 4] Production of liner d (thickness: 50 μm) In the same manner as in Production Example 1, except that a 50 μm thick PET film (manufactured by Toray Industries, Inc., trade name “Lumirror S10”) was used as the PET film. A liner d having a thickness of 50 μm was obtained. The Si-Kα ray intensity of the resulting liner was 35 (kcps).

[Production Example 5] Production of liner e (thickness: 26 µm) The procedure was the same as in Production Example 1, except that a 26 µm-thick olefin film (manufactured by Toray Industries, Inc., trade name "Torefan") was used instead of the PET film. Thus, a liner e having a thickness of 26 μm was obtained. The Si-Kα ray intensity of the resulting liner was 12 (kcps).

[Production Example 6] Liner f (thickness: 38 µm)
As the liner f, a PET film with a release treatment layer having a thickness of 38 μm (manufactured by Mitsubishi Plastics, Inc., trade name “MRF38”) was prepared. The Si-Kα ray intensity of the liner was 18 (kcps).

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

[Production Example 8] Production of liner h (thickness: 5 μm) In the same manner as in Production Example 1, A liner h having a thickness of 5 μm was obtained. The Si-Kα ray intensity of the obtained liner was 1.0 (kcps).

[Production Example 9] Production of liner i (thickness: 75 µm) The procedure was the same as in Production Example 1, except that a 75 µm-thick olefin film (manufactured by Toray Industries, Inc., trade name "Torayfan") was used instead of the PET film. Thus, a liner i having a thickness of 75 μm was obtained. The Si-Kα ray intensity of the resulting liner was 13 (kcps).

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

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

[Production Example 12] Production of base polymer 3 In ethyl acetate, 70 parts of methyl acrylate, 2 parts of butyl acrylate, 30 parts of 2-ethylhexyl acrylate, 10 parts of acrylic acid, and 0.1 part of benzoyl peroxide as a polymerization initiator were mixed. After adding 2 parts, the mixture was heated to obtain an ethyl acetate solution of an acrylic copolymer (polymer 3). Note that 8.9% by weight of the monomer-derived repeating units constituting the polymer 3 are repeating units derived from a monomer having an active hydrogen group.

[Production Example 13] Production of base polymer 4 In toluene, 50 mol of butyl acrylate, 50 mol of ethyl acrylate, 24 mol of 2-hydroxyethyl acrylate, and benzoyl peroxide (butyl acrylate, ethyl acrylate and 2 -0.2 parts per 100 parts of total hydroxyethyl acrylate) was added, and then heated to obtain a toluene solution of an acrylic copolymer (polymer 4). Note that 19.6% by weight of the monomer-derived repeating units constituting the polymer 4 are repeating units derived from a monomer having an active hydrogen group.

[Production Example 14] Production of base polymer 5 In toluene, 50 mol of butyl acrylate, 50 mol of ethyl acrylate, 24 mol of 2-hydroxyethyl acrylate, and benzoyl peroxide (butyl acrylate, ethyl acrylate and 2 - 0.2 parts per 100 parts of total hydroxyethyl acrylate) was added, and then heated to obtain a copolymer solution. After adding 2-isocyanatoethyl acrylate in an amount corresponding to 78 mol% of the hydroxyl groups derived from 2-hydroxyethyl acrylate in the solution to the copolymer solution, heating is performed to obtain 2-isocyanatoethyl methacrylate was added to the hydroxyl groups of to obtain a toluene solution of an acrylic copolymer (polymer 5) having methacrylate groups in side chains. In addition, 3.4% by weight of the repeating units derived from the monomer constituting the polymer 5 are repeating units derived from the monomer having an active hydrogen group.

[Example 1]
(Preparation of undercoat layer/substrate laminate)
Mixed solution A was prepared by mixing a toluene solution of polymer 1 (polymer 1: 100 parts) and 3 parts of an isocyanate-based cross-linking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L").
Lumirror S10 (thickness: 25 μm) manufactured by Toray Industries, Inc. was used as the base material, and the mixed solution A was applied to one surface thereof using an applicator so that the thickness after solvent evaporation (drying) was 13 μm, After that, the solvent was volatilized (dried) to obtain an undercoat layer/substrate laminate.
(Preparation of first liner/first pressure-sensitive adhesive layer (containing thermally expandable microspheres) laminate)
A toluene solution of polymer 1 (polymer 1: 100 parts), an isocyanate cross-linking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L") 1.5 parts, and a cross-linking aid (manufactured by Tokyo Fine Chemical Co., Ltd., trade name "OL -1") 0.05 part, 10 parts of a tackifying resin (manufactured by Sumitomo Bakelite Co., Ltd., trade name "Sumilite PR12603"), and thermally expandable microspheres (manufactured by Matsumoto Yushi Seiyaku Co., Ltd., trade name "FN-180SSD") A mixed solution B was prepared by mixing 30 parts and 0.5 parts of a coloring agent (manufactured by Dainichiseika Kogyo Co., Ltd., trade name “DYMICS SZ-7510 Green”).
The mixed solution B was applied to the surface of the liner a to which the release treatment agent was applied so that the thickness after evaporation (drying) of the solvent was 35 μm. After that, the solvent was volatilized (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/substrate laminate)
The first liner/first pressure-sensitive adhesive layer laminate and the undercoat layer/base layer laminate are laminated so that the first pressure-sensitive adhesive layer and the undercoat layer face each other to form the first liner/first adhesive layer. A pressure-sensitive adhesive layer (containing heat-expandable microspheres)/undercoat layer/substrate laminate of No. 1 was obtained.
(Preparation of second pressure-sensitive adhesive layer/second liner laminate)
A toluene solution of polymer 1 (polymer 1: 100 parts), an isocyanate cross-linking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L") 1.5 parts, and a cross-linking aid (manufactured by Tokyo Fine Chemical Co., Ltd., trade name "OL -1") and 10 parts of a plasticizer (manufactured by DIC, trade name "Monocizer W700") to prepare a mixed solution C.
The mixed solution C was applied to the surface of the liner b to which the release treatment agent was applied so that the thickness after evaporation (drying) of the solvent was 10 μm. After that, the solvent was volatilized (dried) to obtain a second adhesive layer/second liner laminate.
(Preparation of double-sided pressure-sensitive adhesive sheet with liner)
The first liner/first pressure-sensitive adhesive layer (containing heat-expandable microspheres)/undercoat layer/substrate laminate and the second pressure-sensitive adhesive layer/second liner laminate are combined with the substrate and the second The 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/ A second adhesive layer)/second liner) was obtained.

[Examples 2 to 18, 20 to 23, Comparative Example 1]
A liner-equipped double-sided pressure-sensitive adhesive 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 Co., Ltd., trade name "Tetrad C", epoxy-based cross-linking agent <tackifier>
SUMILITE PR12603: manufactured by Sumitomo Bakelite Co., Ltd., trade name "SUMILITE RESIN PR12603"
S145: manufactured by Yasuhara Chemical Co., Ltd., trade name "YS Polyster S145"
<Heat-expandable microspheres>
F-30D: Matsumoto Yushi Seiyaku Co., Ltd., trade name “Matsumoto Microsphere F-30D”, foaming (expansion) start temperature: 70° C. to 80° C., maximum expansion temperature: 110° C. to 120° C., average particle size of 10 μm or more 18 μm
FN-180SSD: manufactured by Matsumoto Yushi Seiyaku Co., Ltd., trade name "Matsumoto Microsphere FN-180SSD", foaming (expansion) start temperature: 135° C. to 150° C., maximum expansion temperature: 165° C. to 180° C., average particle size of 15 μm or more 25 μm
F-230D: manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., trade name “Matsumoto Microsphere F-230D”
F-50D: Matsumoto Yushi Pharmaceutical Co., Ltd., trade name “Matsumoto Microsphere F-50D”
<Colorant>
DYMICS SZ-7200 Red: manufactured by Dainichiseika Kogyo Co., Ltd., trade name “DYMICS SZ-7200 Red”

[Example 19]
(Preparation of undercoat layer/substrate laminate)
A toluene solution of polymer 4 (polymer 4: 100 parts), an ultraviolet curable urethane acrylate (UV7620EA: manufactured by Nippon Synthetic Chemical Co., Ltd., trade name “Shikou UV-7620EA”) as an active energy ray-reactive oligomer 40 parts, and an epoxy 0.5 parts of a cross-linking agent (manufactured by Mitsubishi Gas Chemical Co., Ltd., trade name "Tetrad C") and 3 parts of an energy ray polymerization initiator (manufactured by BASF Japan, trade name "Irgacure 651") are mixed to form a mixture. prepared. To this mixed solution, the same solvent (toluene) as the solvent in the mixed solution was further added to adjust the viscosity to a viscosity that facilitates coating, thereby obtaining a mixed solution A'.
As a substrate, on one side of Lumirror S10 (thickness 50 μm) manufactured by Toray Industries, Inc., a blue printing ink CVL-PR (manufactured by DIC Graphics) is applied with a gravure coater so that the coating thickness after drying is 2 μm (solid A film formed by printing) was prepared. The mixed solution A' was applied to one surface of the substrate using an applicator, and then the solvent was volatilized (dried) to obtain a laminate consisting of the precursor layer of the undercoat layer and the substrate.
(Preparation of first liner/first pressure-sensitive adhesive layer (containing thermally expandable microspheres) laminate)
A toluene solution of polymer 4 (polymer 4: 100 parts), an ultraviolet curable urethane acrylate (UV7620EA: manufactured by Nippon Synthetic Chemical Co., Ltd., trade name “Shikou UV-7620EA”) as an active energy ray-reactive oligomer 40 parts, and an epoxy 0.5 parts of a cross-linking agent (manufactured by Mitsubishi Gas Chemical Company, trade name "Tetrad C"), 3 parts of an energy beam polymerization initiator (manufactured by BASF Japan, trade name "Irgacure 651"), and thermally expandable microspheres ( Matsumoto Yushi Seiyaku Co., Ltd., trade name "F-30D") was mixed with 30 parts to prepare a mixed solution. To this mixed solution, the same solvent (toluene) as the solvent in the mixed solution was further added to adjust the viscosity to a viscosity that facilitates coating, thereby obtaining a mixed solution B'.
The mixed solution B' was applied to the surface of the liner c to which the release treatment agent was applied. Thereafter, the solvent was volatilized (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/substrate laminate)
A laminate consisting of a first liner/first pressure-sensitive adhesive layer precursor layer and a laminate consisting of an undercoat layer precursor layer/base material are combined into the first pressure-sensitive adhesive layer precursor layer and the undercoat layer precursor layer. , to obtain a laminate consisting of the first liner/precursor layer of the first pressure-sensitive adhesive layer (containing thermally expandable microspheres)/precursor layer of the undercoat layer/substrate.
(Preparation of second pressure-sensitive adhesive layer/second liner laminate)
A toluene solution of polymer 5 (polymer 1: 100 parts), an isocyanate cross-linking agent (manufactured by Nippon Polyurethane Co., Ltd., trade name "Coronate L") 0.2 parts, and an energy ray polymerization initiator (manufactured by BASF Japan, trade name A mixed solution C′ was prepared by mixing 3 parts of “Irgacure 651”).
The mixed solution C′ was applied to the surface of the liner f to which the release treatment agent was applied. Thereafter, the solvent was volatilized (dried) to obtain a laminate consisting of the precursor layer of the second pressure-sensitive adhesive layer/second liner.
(Preparation of double-sided pressure-sensitive adhesive sheet with liner)
A laminate consisting of a first liner/precursor layer of the first pressure-sensitive adhesive layer (containing thermally expandable microspheres)/precursor layer of the undercoat layer/substrate, and precursor layer of the second pressure-sensitive adhesive layer/second A laminate comprising a liner was attached so that the substrate and the precursor layer of the second pressure-sensitive adhesive layer faced each other. After that, using an ultraviolet irradiator (manufactured by Nitto Seiki Co., Ltd., trade name "UM810 (high-pressure mercury lamp light source)"), each precursor layer was irradiated with ultraviolet light at an integrated light amount of 300 mJ/cm ² . As described above, 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; thickness: 25 μm)/undercoat layer (25 μm)/substrate/second Two adhesive layers (10 μm))/second liner) were obtained.

[evaluation]
The liner-attached double-sided PSA sheets obtained in Examples and Comparative Examples were subjected to the following evaluations. The results are shown in Tables 1-5.

(1) Evaluation of liner peeling operability a
With the first liner on the upper side, a liner-attached double-sided adhesive sheet (50 mm × 100 mm) is attached to a metal plate (SUS304 plate, thickness 3 mm) to prepare a measurement sample (a).
In addition, with the second liner facing upward, a liner-equipped double-sided pressure-sensitive adhesive sheet (50 mm × 100 mm) is attached to a metal plate (SUS304 plate) via a double-sided tape (manufactured by Nitto Denko Co., Ltd., trade name "No. 500"). , thickness 3 mm) to prepare a measurement sample (b).
For the measurement sample (a) and the measurement sample (b), the upper liner was picked up with bare hands and folded back under an environment of 23° C./65% RH, and the liner peeling operability was evaluated according to the following criteria.
Excellent (◯ in the table): Folding was completed within 30 seconds.
Good (Δ in the table): It took 30 seconds or more, but it could be turned back.
Impossible (X in the table): The adhesive layer was torn off before folding, unnecessary lifting (peeling) occurred, etc., resulting in a result that does not correspond to "excellent" or "good".

(2) Evaluation of liner peeling operability b
A measurement sample (a) and a measurement sample (b) were prepared in the same manner as in (1) above.
Regarding the measurement sample (a) and the measurement sample (b), the liner peeling operability was evaluated under the environment of 23° C./65% RH by the following operation.
On the upper liner, a tape (manufactured by Nichiban Co., Ltd., trade name "Cellotape (registered trademark) No. 405" (for industrial use, 18 mm width)) is attached as shown in FIG. , to prepare a measurement sample (c). The measurement sample (c) was attached to a tensile tester with a constant temperature bath (trade name “Shimadzu Autograph AG-120kN” manufactured by Shimadzu Corporation). After that, the tape was pulled in the longitudinal direction (to the right of the paper) under the conditions of a set peeling angle of 180°, a constant force, and a peeling speed of 300 mm/min, and the separation of the upper liner from the double-sided adhesive sheet was observed. Evaluation was made according to the following criteria.
Excellent (◯ in the table): The upper liner was peeled off while maintaining the peel angle of 180°.
Good (Δ in the table): The upper liner was peeled off, although the peel angle of 180° was not maintained.
Impossible (x in the table): The adhesive layer was torn, and separation phenomena such as peeling at the lower liner/adhesive layer interface were observed.

(3) Roll Winding Test A double-faced pressure-sensitive adhesive sheet with a liner having a length of 2 m and a width of 0.3 m was wound around a pipe having an outer diameter of 5 cm with the second liner on the outside. At this time, both ends of the liner-attached double-sided pressure-sensitive adhesive sheet were fixed with terminal tapes (manufactured by Nichiban Co., Ltd., trade name "Cellotape (registered trademark) No. 405" (industrial use, 18 mm width), 20 mm x 18 mm).
The liner-attached double-sided pressure-sensitive adhesive sheet wrapped around the pipe as described above was stored in an environment of 40° C./50% RH for 72 hours.
After that, the appearance of the liner-attached double-sided pressure-sensitive adhesive sheet was visually confirmed, and roll winding property was evaluated according to the following criteria.
Excellent (○ in the table): No change in appearance before and after storage.
Good (Δ in the table): Change in appearance is confirmed to the extent that the terminal tape is lifted, but the winding is not loose.
Impossible (X in the table): The winding was loosened and the terminal tape was peeled off, and the peeling of the liner was confirmed.

(4) Liner Peeling Force The second liner was peeled off from the double-sided pressure-sensitive adhesive sheet with liner (50 mm × 180 mm), and the second pressure-sensitive adhesive layer was coated with double-sided tape (manufactured by Nitto Denko Co., Ltd., trade name "No. 500"). A measurement sample was prepared by attaching it to a metal plate (SUS304 plate, thickness: 3 mm) via.
This measurement sample was set in a tensile tester with a constant temperature bath (trade name “Shimadzu Autograph AG-120kN” manufactured by Shimadzu Corporation) and allowed to stand for 30 minutes.
Next, in an environment of 23° C./55% RH, the first liner was peeled off from the double-sided pressure-sensitive adhesive sheet under the conditions of a release angle of 180° and a peeling speed (tensile speed) of 300 mm/min, and the first liner was peeled off. force was measured.
In addition, the first liner was peeled off from the double-sided pressure-sensitive adhesive sheet with liner (50 mm × 180 mm), and the first pressure-sensitive adhesive layer was attached via double-sided tape (manufactured by Nitto Denko Co., Ltd., trade name "No. 500"). A measurement sample was prepared by attaching it to a metal plate (SUS304 plate, thickness: 3 mm), and the peel strength of the second liner was measured in the same manner as described above.

(5) Modulus of elasticity Layers constituting the liner-attached double-sided pressure-sensitive adhesive sheet by cutting the liner-attached double-sided pressure-sensitive adhesive sheet in the thickness direction with a microtome and identifying each layer by visual observation or observation with an optical microscope. was measured for the nanoindenter modulus.
The elastic modulus of the first pressure-sensitive adhesive layer is the elastic modulus of a region without thermally expandable microspheres.
A displacement-load hysteresis curve obtained by pressing a probe (indenter) against the object to be measured was numerically processed using software (triboscan) attached to the measuring device to obtain an elastic modulus (average value of three measurements).
The nanoindenter apparatus and measurement conditions are as follows.
Apparatus and measurement conditions/apparatus: Nanoindenter; Triboindenter manufactured by Hysitron Inc.
・Measurement method: single indentation method
・Measurement temperature: 25°C
・Indentation speed: about 1000 nm/sec
・Indentation depth: about 800 nm
・Probe: Diamond, Berkovich type (triangular pyramid type)

(6) Thickness The liner-equipped double-sided pressure-sensitive adhesive sheet is cut with a trimming cutter in the thickness direction, subjected to Pt—Pd sputtering treatment, and then the cut surface is examined using a Hitachi High-Technologies Corporation S3400N low-vacuum scanning electron microscope (SEM). Observation was made and thickness measurement was performed.
The measurement conditions for SEM observation are as follows Observation image: ESED image Acceleration voltage: 10 kV
*Magnification: 600 times When the interface between the constituent layers was unclear, the following Raman spectrum measurement was also used to determine the interface between the layers, and then the thickness was measured.
(Raman spectrum measurement)
・Excitation wavelength: 532 nm
・Measurement wavenumber range: 300 to 3600 cm-1
・Grating: 600 gr/mm
・Objective lens: x100
・Measurement time: 0.2 sec/1 spectrum ・Measurement range: 20 x 40 µm
・Number of measurements: 100 x 200 points ・Detector: EMCCD

(7) Si-Kα Ray Intensity Measurement of Liner Fluorescent X-ray analysis was performed on 100 randomly selected points on the surface of the liner (release-treated surface). More specifically, the intensity (i) of the Si—Kα ray of the surface of the liner in contact with the adhesive layer (the surface coated with the release agent) and the surface not in contact with the adhesive layer (the surface coated with the release agent) Measure the intensity (ii) of the Si-Kα ray of the surface that is not exposed), obtain the absolute value of the value obtained by subtracting the value of (ii) from the value of (i), and calculate the average value of 100 measurements of the value. The Si—Kα ray intensity of the liner was used.
The intensity of the Si-Kα ray is the intensity at a wavelength of 7.125 angstroms as measured by the following equipment.
Equipment: Rigaku ZSX100e
Analysis area: 30mmφ
Analysis element: Si
Analysis crystal: RX4
Output: 50kV, 70mA

REFERENCE SIGNS LIST 10 double-sided adhesive sheet 11 first adhesive layer 12 substrate 13 second adhesive layer 20 first liner 30 second diner 100 adhesive sheet

Claims

double-sided adhesive sheet,
a first liner releasably disposed directly on one side of the double-sided pressure-sensitive adhesive sheet;
A liner-equipped double-sided pressure-sensitive adhesive sheet comprising a second liner releasably placed directly on the other side of the double-sided pressure-sensitive adhesive sheet,
The double-sided pressure-sensitive adhesive sheet comprises a first pressure-sensitive adhesive layer arranged in contact with the first liner,
The first adhesive layer contains thermally expandable microspheres,
The peel strength of the first liner to 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 to 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 to 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 and the product of the cube of the thickness of the second liner and the elastic modulus of the second liner (I) II) and the sum of all layers (III) of the product of the single layer thickness cubed and the single layer elastic modulus of each layer constituting the double-sided pressure-sensitive adhesive sheet satisfy the following relationships (1) and (2):
Double-sided adhesive sheet with liner.
0.001≦(I)/{(II)+(III)}≦1500 (1)
0.001≦(II)/{(I)+(III)}≦1500 (2)
The liner-equipped double-sided pressure-sensitive adhesive sheet according to claim 1, wherein the double-sided pressure-sensitive adhesive sheet comprises the first pressure-sensitive adhesive layer, a substrate, and a second pressure-sensitive adhesive layer in this order.
The total of all layers (III) 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 is 1×10 −6 Nm to 1×10 −1 Nm. The liner-attached double-sided pressure-sensitive adhesive sheet according to 1 or 2.
The product (I) of the cube of the thickness of the first liner and the elastic modulus of the first liner and the product of the cube of the thickness of the second liner and the elastic modulus of the second liner (I) II) and the sum of all layers (III) of the product of the single layer thickness cubed and the single layer elastic modulus of each layer constituting the double-sided pressure-sensitive adhesive sheet satisfy the following relationship (3): 4. The liner-attached double-sided pressure-sensitive adhesive sheet according to any one of 3.
0.001≦{(I)+(II)}/(III)≦1500 (3)
The liner-equipped double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 4, wherein the first liner and/or the second liner have an Si-Kα ray intensity of 0.01 to 500 kcps by fluorescent X-ray analysis. .
The liner-equipped double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 5, wherein at least one of the layers constituting the double-sided pressure-sensitive adhesive sheet is a colored layer.
The liner-equipped double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 6, wherein the thickness of the first liner and/or the second liner is 10 µm to 100 µm.
The liner-equipped double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 7, wherein the thickness of the first liner and the thickness of the second liner are different.
The liner-equipped double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 8, wherein the first pressure-sensitive adhesive layer and/or the second pressure-sensitive adhesive layer contains an acrylic pressure-sensitive adhesive.
The liner-equipped double-sided pressure-sensitive adhesive sheet according to claim 9, wherein the acrylic pressure-sensitive adhesive contains an acrylic polymer containing a structural unit derived from a monomer having an active hydrogen group.
11. The liner-equipped product according to claim 10, wherein the content of the constituent units derived from the monomer having an active hydrogen group is 0.1% by weight to 20% by weight with respect to all the constituent units constituting the acrylic polymer. Double-sided adhesive sheet.
12. Any one of claims 1 to 11, wherein the absolute value of the difference between the peel strength of the first liner to the double-sided pressure-sensitive adhesive sheet and the peel strength of the second liner to the double-sided pressure-sensitive adhesive sheet is 0.5 N/50 mm or less. The double-sided pressure-sensitive adhesive sheet with a liner described in .
The liner-equipped double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 12, which is in the form of a roll.
The liner-equipped double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 13, which is used as a sheet for temporarily fixing a semiconductor chip during the manufacture of CSP (Chip Size/Scale Package).
The liner-equipped double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 13, which is used as a sheet for temporarily fixing a semiconductor chip when manufacturing a WLP (Wafer Level Package).
16. The liner-equipped double-sided pressure-sensitive adhesive sheet according to any one of claims 1 to 15, which is used for processing including a step of removing said second liner first.