JPH04309583A - Self-adhesive sheet - Google Patents

Abstract

PURPOSE:To provide a self-adhesive sheet which has a self-adhesive power changeable by a simple operation after being applied to an adherend. CONSTITUTION:One surface of a shape memory film made from a styrene- butadiene copolymer is embossed at the surface temp. of 130 deg.C to form an emboss pattern on the surface, which is then flattened by pressing on a mirror finish roll at 80 deg.C, thus giving a shape memory film 2. The film 2 is laminated with a release film 5 having a self-adhesive layer 3 formed on one side of the film 5 in such a manner that the flattened surface of the film 2 is in contact with the self-adhesive layer 3, thereby giving a self-adhesive sheet 1. While the self-adhesive surface of the sheet 1 is flat before heating, it deforms by heating, thus decreasing the contact area of the self-adhesive layer 3 with an adherend and facilitating release of the sheet 1.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive sheet whose adhesive strength can be changed by applying a certain temperature after being applied to an adherend.

0002

[Prior art] Conventionally, general-purpose adhesives (acrylic,
Adhesive sheets are known that are made by coating the surface of a base sheet with a rubber-based material, etc. Once pasted, they can be peeled off as needed, making them particularly suitable for temporary adhesion (for temporary fixing) and It is used for various purposes such as simple adhesion. In recent years, adhesive sheets have been used industrially for processes such as manufacturing and assembly, and as adhesive sheets for such processes, for example, when cutting silicon wafers into chips or polishing them in semiconductor manufacturing processes, Dicing tapes used to temporarily fix the wafer, masking tapes used to mask unpainted areas during painting, and protect films used to protect the surface until use are known. These adhesive sheets are required to have sufficient adhesion strength when attached to the adherend during use, and to be easy to peel off (low peeling force) after use, so they are made from conventional general-purpose adhesives. Since adhesive sheets cannot meet these demands, improved adhesive sheets with variable adhesive strength have been proposed. The above-mentioned pressure-sensitive adhesive sheet with variable peeling force can be used by: 1) forming an intermediate layer made of an ethylene copolymer containing an anionic surfactant between a base layer made of a plastic film or the like and a general-purpose pressure-sensitive adhesive layer; When an adhesive sheet is formed and peeled off after being attached to an adherend, the surfactant is diffused into the adhesive layer by heating it to about 70°C or higher.
A product that reduces the adhesive strength of a release sheet to facilitate peeling (Japanese Patent Publication No. 1-31798). 2) A blended resin made by mixing a general-purpose acrylic adhesive and an ionizing radiation-curable resin such as urethane acrylate is applied to the surface of the base sheet to form an adhesive layer, and then applied to the adherend. When peeling off after pasting, the adhesive layer is irradiated with ionizing radiation such as ultraviolet rays to crosslink the ionizing radiation-curable resin in the adhesive layer, forming a three-dimensional network structure and reducing adhesive strength. (for example, JP-A-60-196956, JP-A-61-285)
72 etc.) have been proposed.

0003

[Problem to be solved by the invention] However, the above 1
) When heating an adhesive sheet using a surfactant during peeling, it takes time for the surfactant to transfer from the intermediate layer to the adhesive layer, and heating conditions may vary depending on the type of adhesive, coating thickness, etc. In addition, there was a further problem in that the surfactant adhered to the surface of the adherend after peeling, contaminating the adherend. In addition, the adhesive layer was
For adhesive sheets with a dimensional network structure, the three-dimensional state of the adhesive layer is not constant after irradiation with ionizing radiation, and there are large variations in adhesive strength, and it is difficult to peel off when attached to an adherend. There is a problem that it cannot be used in a place that is exposed to ultraviolet rays etc. until it is used, and furthermore, the adhesive sheet itself must be stored before use in a place where it is not exposed to ultraviolet rays or other ionizing radiation. There are many restrictions in terms of safety and conditions, and the sheets themselves are expensive. Also, 1 above
), 2) Conventional adhesive sheets have a change in adhesive strength that is strong at the initial stage of adhesion, but becomes weaker due to some treatment when peeled off, and conversely, weak adhesive strength at the beginning becomes weak at the beginning. Even after this treatment, the adhesive became stronger and a pressure-sensitive adhesive sheet with good shelf life could not be produced. The present invention aims to solve the above-mentioned drawbacks of the prior art, and provides an adhesive sheet whose adhesive strength changes with a simple operation after being applied to an adherend, making it easy to peel off, and easy to store and use. The purpose is to provide

0004

[Means for Solving the Problems] The pressure-sensitive adhesive sheet of the present invention has a shape-memory resin film made of a shape-memory resin and a pressure-sensitive adhesive layer laminated thereon. Moreover, the adhesive sheet of the present invention is
In a pressure-sensitive adhesive sheet in which a shape-memory resin film made of a shape-memory resin and a pressure-sensitive adhesive layer are laminated, a base sheet is also laminated on the shape-memory resin film side.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below with reference to the drawings. The drawings show one embodiment of the present invention, FIG. 1 shows one example of the pressure-sensitive adhesive sheet of the present invention, and FIG. 2 shows another example of the pressure-sensitive adhesive sheet of the present invention. As shown in FIG. 1, the adhesive sheet 1 of the present invention has a structure consisting of at least a shape memory resin film 2 made of a shape memory resin and an adhesive layer 3. Further, the pressure-sensitive adhesive sheet of the present invention may have a structure in which a base sheet 4 is laminated on the shape memory resin film 2 side, as shown in FIG. The adhesive sheet 1 of the present invention has a major feature in that it has a layer made of shape memory resin as the lower layer of the adhesive layer 3, as shown in FIGS. 1 and 2.

The shape memory resin referred to in the present invention generally includes a stationary phase that prevents the fluidity of the resin and fixes the primary shaped shape, and a secondary shaped phase that repeatedly softens and hardens with temperature changes. It consists of a two-phase structure with a reversible phase that fixes the shape. The shape memory phenomenon of the resin occurs in the steps described below. (1) The fixed shape memory resin for primary shaping is melted at a temperature higher than the melting temperature at which both the stationary phase and the reversible phase become soft, and after primary shaping, the resin is cooled until both of the above phases become hardened. do. (2) After performing secondary shaping by increasing the temperature to a temperature above the shape deformation temperature and below the melting temperature at which only the fixed reversible phase of the secondary shaping becomes a softened state, both of the above phases become hardened again. Cool until cool. (3) Shape memory recovery When the temperature is raised to a temperature above the shape deformation temperature and below the melting temperature at which only the reversible phase becomes soft again, the shape of the secondary shaping is dissolved and the shape of the memorized primary shaping is to recover. The internal mechanisms of the above-mentioned stationary phase and reversible phase differ depending on the type of shape memory resin. Examples of the internal mechanisms of the stationary phase include entanglement between polymer chains, chemical crosslinking, crystal formation/melting,
Formation and melting of a phase structure can be mentioned, and internal mechanisms of the reversible phase include, for example, freezing of chain motion due to glass transition, formation and melting of crystals, and formation and melting of a phase structure.

Specific examples of shape memory resins having such properties include styrene-butadiene copolymer, polyurethane, polynorbornene, transpolyisoprene,
polyolefin, fluororesin, polycaprolactone,
Examples include resins such as polyamide. Among these, preferred resins include styrene-butadiene copolymer, polyurethane, polynorbornene, and transpolyisoprene, as shown below.

As a preferred shape memory resin, 1) the styrene-butadiene copolymer resin is a hybrid polymer consisting of a polystyrene unit and a crystalline polybutadiene unit. In other words, this resin undergoes primary shaping using a structure in which the high melting point crystal part of the polystyrene unit is the stationary phase, while secondary shaping is carried out by utilizing the structure in which the low melting point crystal part of the polybutadiene unit is the reversible phase. and recovery is possible. As such a resin, for example, a commercially available product "Asmar" manufactured by Asahi Kasei Corporation can be used. 2) Polyurethane resin is obtained by controlling the ratio of hard segments and soft segments of thermoplastic polyurethane resin obtained by chain-extending and polymerizing diisocyanate and polyol, and has a glass transition temperature in the range of -30 to +70°C. It is a polymer in which the elastic modulus ratio before and after the glass transition point is arbitrarily set in the range of 20 to 180. At temperatures above the glass transition temperature, the molecular motion of this resin is restrained by cross-linking or partial crystallization of the molecular chains, and the resin exhibits rubber elasticity. In this state, stress is applied and deformed to orient the molecular chains, and the resin is then brought to a temperature below the glass transition temperature. When the oriented molecular chains are fixed and the secondary immobilization is carried out again to a temperature above the glass transition point, the orientation of the molecular chains is released and the original shape is recovered. Examples of such resins include commercial products such as "MM-2500", "MM-3500", and "MM-4" manufactured by Mitsubishi Heavy Industries, Ltd.
500", "MM-5500", etc. 3) Transpolyisoprene has a melting point of 67°C and a crystallinity of 40%.
It is a crystalline polymer shown below and is a resin that can be crosslinked with sulfur, peroxide, or the like. In this resin, a stationary phase is formed by crosslinking of polydiene double bonds, and a reversible phase of softening and hardening is formed by crystalline portions. As such a resin, for example, a commercially available product is "transpolyisoprene (TPI)" manufactured by Kuraray Co., Ltd. 4) Polynorbornene resins include those based on polymers with a molecular weight of about 3 million obtained by ring-opening polymerization of cyclopentadiene monomer and ethylene. This resin is a resin that performs primary shaping using the entanglement of ultra-high molecular weight polymers as a stationary phase, and can perform secondary shaping and recovery using chain movement caused by glass transition of polynorbornene. As such a resin, for example, "N" manufactured by Zeon Corporation is a commercially available product.
ORSOREX" is available.

[0009] To form the shape memory resin film 2,
First, a sheet is formed using a known thermoplastic resin film forming method, such as melting the above resin and extruding it, or dissolving it in an appropriate solvent and casting it on the surface of the substrate to be coated. to form. Next, the sheet is heated to a temperature higher than the melting temperature to perform primary shaping into an arbitrary shape, and then cooled until the stationary phase and reversible phase are in a hardened state to fix the shape of the primary shaping. . In addition, the primary shaping may be performed by forming the surface of the substrate to be coated into an arbitrary shape such as an uneven surface or a mirror surface during casting, and simultaneously performing the primary shaping of the shape memory resin itself and forming it into a sheet. . Then, it is heated to a temperature above the shape deformation temperature at which only the reversible phase softens and below the melting temperature, and after performing the desired secondary shaping, it is cooled again to harden the shape of the secondary shaping, and then the primary shaping is performed. A shape memory resin film whose shape is memorized can be obtained. Note that the temperatures of the primary shaping and secondary shaping can be appropriately selected depending on the type of shape memory resin used. The shape memory resin preferably has a relationship of room temperature<shape deformation temperature (secondary forming temperature)<shape recovery temperature<melting temperature (first forming temperature).

The above melting temperature is the temperature at which the stationary phase of the resin becomes molten, and the shape deformation temperature is the temperature at which the reversible phase of softening and hardening of the resin softens. To give a specific example of the above temperature, for example, when a styrene-butadiene copolymer resin is used as the shape memory resin, the melting temperature is approximately 120°C, and when the temperature exceeds this temperature, both the stationary phase and the reversible phase become molten. By further cooling to room temperature, both the stationary phase and the reversible phase can be solidified and the shape can be fixed (primary shaping fixation). In addition, the shape deformation temperature is 60°C to 80°C, and when heated to this temperature, only the reversible phase melts (the stationary phase does not melt). After molding into any shape in this state,
When cooled to below .degree. C., the reversible phase hardens and the shape can be fixed (secondary shaping fixation). Furthermore, the recovery temperature for reproducing the memory shape (the shape of the primary molding) is 60 to 90°C, and when heated to this temperature, a reversible phase crystal that temporarily fixes the deformation during the secondary molding occurs. The portion can be melted and the shape of the primary mold can be memorized and recovered.

FIGS. 3 and 4 show an example of the use of the adhesive sheet of the present invention, and are longitudinal cross-sectional views showing a state in which the release sheet 5 of the adhesive sheet shown in FIG. 1 has been peeled off and adhered to an adherend 6. The shape of the primary mold and the shape of the secondary mold used in the pressure-sensitive adhesive sheet of the present invention are not particularly limited, but the shapes of the primary mold (FIG. 4) are The film 2 was shaped so that the specific surface area was smaller than that of the secondary shaped shape (FIG. 3), and when reheated, the film 2
It is desirable to restore the primary shaped shape that has been memorized (FIG. 3) so that the adhesive force decreases. In addition, when laminating the base sheet 4 on the film 2 side as shown in FIG. 2, the film 2 may be deformed in the same manner as described above. When the adhesive sheet 1 is formed as described above, when the adhesive sheet 1 is heated to a temperature higher than the temperature of the secondary molding to recover the memorized shape of the primary molding, the adhesive layer 3 laminated on the film 2 is removed from the film 2. The contact area with the adherend decreases accordingly. Therefore, it is preferable because the adhesive tape 1 can be easily peeled off from the adherend 6 simply by heating. Note that the specific surface area in this case refers to the contact area per constant area when the shape memory resin film 2 is brought into contact with a smooth surface, and in this way, the shape of the primary shaping and secondary shaping is changed. To change the specific surface area, for example, to increase the specific surface area, the surface should be smoothed with a mirror finish, etc., and to decrease the specific surface area, the surface should be smoothed by embossing, etc. It may be made into an uneven shape.

Further, in the present invention, the specific surface area of the primary shaped shape memory resin film 2 can be formed to be larger than the specific surface area of the secondary shaped shape. That is, for example, the surface of the film 2 in contact with the adhesive layer 3 is formed smooth in the primary forming state, such as the adhesive sheet 1 shown in FIG. 3, and the film 2 is formed in the secondary forming state as shown in FIG. The contact surface with the adhesive layer 3 is formed using means such as embossing so that the specific surface area is small. As shown in FIG. 4, when this adhesive sheet 1 is attached to an adherend 6 during use, the contact area of the adhesive layer 3 with the adherend 6 is small and the adhesive force is low, and the deformation temperature When heating is performed above, the specific surface area of the film 2 increases as shown in FIG. The contact area between the adherend 6 and the adherend 6 becomes larger, and the adhesive force can be increased. When the adhesive sheet is formed as described above, when the adhesive sheet is temporarily attached and then the final adhesion is performed, the adhesive sheet can be pressurized by a simple operation such as heating after temporarily attaching the adhesive sheet. There is an advantage that the adhesive strength can be easily increased and the main adhesion can be completed without any contact.

As the resin forming the adhesive layer 3 of the adhesive sheet 1 of the present invention, any of the common acrylic, rubber, and silicone adhesives used in conventionally known adhesive sheets can be used. It can be used regardless of whether it is a solvent type or an emulsion type, and an ionizing radiation curable resin can also be used. Specific examples of the resin forming the adhesive layer include rubber resins such as polyisoprene rubber, acrylic resins such as (meth)acrylate resins, polyvinyl ether resins,
Tackifier suitable for any adhesive such as polyvinyl acetate resin, vinyl chloride vinyl acetate copolymer resin, polystyrene resin, polyester resin, polyamide resin, polychlorinated olefin resin, polyvinyl butyral resin, etc. For example, rosin, dammar, polymerized rosin, partially hydrogenated rosin, ester rosin, polyterpene resin, modified terpene, petroleum resin, cyclopentadiene resin,
Phenolic resin, styrene resin, xylene resin,
Phenolic resin, styrene resin, xylene resin,
A suitable amount of coumaron-indene resin, etc. is added, and if necessary, a softener, filler, anti-aging agent, etc. can also be added. In the case of a solvent-based adhesive, an organic solvent or the like may be added as necessary to adjust the viscosity, so that it can be used directly by coating methods such as roll coating, die coating, knife coating, and gravure coating. The adhesive layer can be formed using a coating method, a transfer coating method, etc., and selecting an appropriate adhesive layer in consideration of the heat resistance, ionizing radiation resistance, coating thickness, smoothness, composition of the paint, etc. of the base sheet. can. The pressure-sensitive adhesive layer formed in this manner may have any thickness, but it is generally desirable to form the pressure-sensitive adhesive layer to a thickness of about 10 to 50 μm.

The material of the base sheet 4 is not particularly limited. For example, the materials of the base sheet include paper such as tissue paper, bleached kraft paper, titanium paper, linter paper, paperboard, and gypsum board paper, polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyethylene terephthalate, polycarbonate, and nylon. , polystyrene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, ionomer, thermoplastic resin film such as (meth)acrylic polymer, phenolic resin, urea resin, unsaturated polyester resin, urethane resin,
Plate (sheet) of thermosetting resin such as epoxy resin and melamine resin, metal foil or sheet of iron, aluminum, copper, etc., metal plate such as galvanized steel sheet, wood base material such as wood, gypsum base material such as gypsum board, etc. Examples include base materials, fiber cement boards such as pulp cement boards, cement boards such as lightweight foamed concrete boards, slate boards, ceramic boards such as enamel, and composites of the above-mentioned base materials.

As shown in FIG. 1, the pressure-sensitive adhesive sheet of the present invention can also have a release sheet 5 laminated on the surface of the pressure-sensitive adhesive layer. The material of the release sheet 5 is not particularly limited as long as it has releasability from the adhesive layer, but it is usually the above-mentioned base sheet, a plastic sheet whose surface has been subjected to a release treatment, paper, etc. is used. For mold release treatment, a coating layer is formed by applying a fluororesin, silicone, melamine, polyolefin, ionizing radiation-curable resin, etc. In addition, when the release sheet 5 is not used, for example when the adhesive sheet is continuously formed into a roll shape, a release sheet is placed on the back side of the shape memory resin film 2 (base sheet 4 in the case of FIG. 2) as described above. It may be formed so that it can be separated from the adhesive layer 3 by treatment.

Although not particularly shown in the drawings, the pressure-sensitive adhesive sheet of the present invention may be subjected to primer coating or surface treatment on the surface of the film in order to improve the adhesive force between the pressure-sensitive adhesive layer and the shape-memory resin film.

Next, a method for forming the pressure-sensitive adhesive sheet of the present invention will be explained. When forming the adhesive sheet of FIG. 1, the shape memory resin film 2 is subjected to primary shaping and secondary shaping to form a predetermined shape as described above. Then, an adhesive layer 3 is formed on the surface of the film 2, and a release sheet 5 is laminated thereon. Alternatively, after forming the adhesive layer 3 on the surface of the release sheet 5, the film 2 formed into a predetermined shape may be laminated so that the adhesive layer 3 and the film 2 are in contact with each other. Further, when forming the adhesive sheet shown in FIG. 2, the film 2 is subjected to primary shaping and secondary shaping to form it into a predetermined shape. And film 2
After laminating with the base sheet 4, the film 2 is laminated as described above.
The adhesive sheet 1 can be obtained by laminating an adhesive layer 3 and a release layer 5 on the sides.

The adhesive sheet of the present invention can easily change the peeling force by simply heating it after being attached to an adherend, so it can be used as a process adhesive tape, for example, in semiconductor manufacturing processes and multilayer ceramic capacitor manufacturing processes. It can be optimally used for dicing tapes used in dicing processes, masking tapes for painting, protective films, etc.

The present invention will be explained in more detail below with reference to specific examples. Example 1 Shape memory resin consisting of styrene-butadiene copolymer (
A resin solution prepared by dissolving 30 parts by weight of Asmar (manufactured by Asahi Kasei) in 100 parts by weight of toluene was cast to a thickness of 10 mm.
A shape memory resin film of 0 μm was created. Next, the above film was subjected to embossing at a surface temperature of 130° C. to form irregularities on the surface, and then cooled. The embossed film was pressed using a mirror roll at a surface temperature of 80°C to smooth the film surface. On the other hand, an adhesive (SK Dyne, Soken Chemical Co., Ltd.) was coated on the surface of a release film (Therael, manufactured by Toyo Metallizing Co., Ltd.) using a comma coating method, and then dried at 110°C for 2 minutes (coating thickness, 1
5μm dry). This release film and the above shape memory resin film were laminated so that the adhesive layers were in contact with each other to obtain an adhesive sheet. The obtained adhesive sheet is JISZ02
A peel test was conducted in accordance with 37. A stainless steel plate was used as the adherend, and after preparing two stainless steel plates and pasting adhesive sheets on each plate, a peel test was performed on one plate as it was, and the other plate was heated at 80°C for 5 minutes. After that, a peel test was conducted. As a result, the unheated adhesive sheet was 300g/25
The other pressure-sensitive adhesive sheet that was heated showed an adhesive strength of 50 g/25 mm. That is, it was confirmed that the adhesive force of the above-mentioned release sheet was reduced by heating, and peeling became easier.

Example 2 30 parts by weight of a shape memory resin made of styrene-butadiene copolymer (Asmar, manufactured by Asahi Kasei Co., Ltd.) was added to the surface of a 50 μm thick PET film (T60 manufactured by Toray Industries, Ltd.) and 10 parts by weight of toluene.
A resin solution dissolved in 0 parts by weight was coated using a comma coat method and dried at 80° C. for 1 minute to form a shape memory resin film with a thickness of 30 μm, followed by cooling. Next, the above film was subjected to embossing at a surface temperature of 130° C. to form irregularities in the intermediate layer on the surface. The above embossed film was pressed using a mirror roll at a surface temperature of 80°C,
The intermediate layer on the surface of the film was smoothed. On the other hand, an adhesive (SK Dyne, Soken Chemical Co., Ltd.) was coated on the surface of a release film (Therael, manufactured by Toyo Metallizing Co., Ltd.) using a comma coat method, and then dried at 110°C for 2 minutes (coating thickness,
15μm dry). This release film and the above PE
The T film was laminated so that the shape memory resin film and the adhesive layer were in contact with each other to obtain an adhesive sheet. The resulting pressure-sensitive adhesive sheet was subjected to a peel test in accordance with JIS Z0237. A stainless steel plate was used as the adherend, and after preparing two stainless steel plates and pasting adhesive sheets on each plate, a peel test was performed on one plate as it was, and the other plate was heated at 80°C for 5 minutes. After that, a peel test was conducted. As a result, the unheated adhesive sheet showed an adhesive force of 500 g/25 mm, and the other heated adhesive sheet showed an adhesive force of 50 g/25 mm. That is, it was confirmed that the adhesive force of the above-mentioned release sheet was reduced by heating, and peeling became easier.

[0020]

Effects of the Invention As explained above, the adhesive sheet of the present invention has a structure in which a shape memory resin film made of a shape memory resin and an adhesive layer are laminated, so that the lower layer of the adhesive layer can be arbitrarily removed by heating. It is possible to change the shape, and since the adhesive layer deforms to follow the shape of the shape memory resin film, it is possible to change the contact area between the adhesive sheet and the adherend after pasting. The peeling force can be changed arbitrarily with a simple operation of heating. If the shape memory resin film is shaped so that the specific surface area of the primary shaped shape is smaller than the specific surface area of the secondary shaped shape, the adhesive strength may be significantly reduced by heating. It has the effect of making it easier to peel off, and compared to adhesive sheets that use conventional surfactants or adhesive sheets that have an ionizing radiation-curable resin mixed in the adhesive layer, it has the effect of making peeling easier. It is possible to obtain a pressure-sensitive adhesive sheet that is free from problems such as the risk of surface active agent adhering to the surface of the adherend and contaminating the adherend, variation in adhesive strength, and restrictions on the place where it can be used. In addition, by laminating the base sheet on the shape memory resin film side, any material can be selected for the base sheet, which expands the range of material selection and reduces the amount of shape memory resin used. This has the effect of reducing the material cost of adhesive sheets.

[Brief explanation of drawings]

FIG. 1 is a partial vertical cross-sectional view showing one example of the adhesive sheet of the present invention.

FIG. 2 is a partial longitudinal sectional view showing another example of the pressure-sensitive adhesive sheet of the present invention.

FIG. 3 is a partial longitudinal sectional view showing an example of use of the adhesive sheet of the present invention.

FIG. 4 is a partial longitudinal sectional view showing an example of use of the adhesive sheet of the present invention.

[Explanation of symbols]

1 Adhesive sheet 2 Shape memory resin film 3 Adhesive layer 4 Base sheet

Claims (2)

[Claims] 1. A pressure-sensitive adhesive sheet comprising a shape-memory resin film made of a shape-memory resin and a pressure-sensitive adhesive layer. 2. A pressure-sensitive adhesive sheet comprising a shape-memory resin film made of a shape-memory resin and a pressure-sensitive adhesive layer, the pressure-sensitive adhesive sheet comprising a base sheet laminated on the shape-memory resin film side.