Adhesive sheet with release film

Abstract

The invention relates to an adhesive sheet with a release film. Provided is an adhesive sheet with a release film. Provided is an adhesive sheet having an adhesive surface having high surface smoothness. According to the present specification, provided is an adhesive sheet with a release film, which is provided with an adhesive sheet and a release film laminated on the adhesive surface of the adhesive sheet. The maximum height Rz of the adhesive surface side surface of the release film of the adhesive sheet with the release film is less than 400 nm.

Description

[0001] This application is a divisional application of an application with the application number 202110342365.2, the application date of March 30, 2021, and the title of “Adhesive sheet with release film”. TECHNICAL FIELD

[0002] The present application relates to an adhesive sheet with a release film. BACKGROUND

[0003] Generally, an adhesive (also referred to as a pressure-sensitive adhesive. The same applies hereafter.) has a property of exhibiting a soft solid (viscoelastic body) state in a temperature range around room temperature, and easily adhering to an adherend by pressure. By virtue of this property, the adhesive is widely used in various industrial fields such as home electric appliances, automobiles, OA equipment, and the like, in the form of an adhesive sheet including a layer of the adhesive.

[0004] Among the above-mentioned adhesive sheets, sometimes a high smoothness is required for the adhesive surface (surface of the adhesive layer). As an example of such an adhesive sheet, an adhesive sheet for optical use can be cited. For example, in Japanese Patent No. 4673344 and Japanese Patent No. 4805999, it is described that the surface roughness (Ra) of the adhesive layer of an optical adhesive sheet is set to a prescribed range with the purpose of improving visual recognition. In addition, in Japanese Patent Application Laid-Open No. 2017-105974, it is described that the ten-point average roughness of the adhesive surface of an adhesive sheet usable for optical use is set to about 1000 nm or less. Furthermore, in Japanese Patent No. 4069625, it is described that in an adhesive sheet to be attached to an optical member such as a polarizing plate, the surface roughness (Ra) of a release film disposed on the surface of the adhesive layer is set to 0.1 μm or less. In Japanese Patent No. 6300788, it is described that the surface roughness (Ra) and the maximum protrusion height (Rp) of a release film are set to a prescribed range. SUMMARY

[0005] In various products such as portable electronic devices, an adhesive sheet can be used in a region to be visually recognized from the outside. For example, an adhesive sheet for a portable electronic device can be used not only on an image display surface of the electronic device but also on a surface other than the same (for example, a back surface). Therefore, for an adhesive sheet used in such a use, sometimes a high transparency not to be felt as its existence is required, and furthermore, a high smoothness can be required for the adhesive surface. If orange peel and streaks exist on the adhesive surface, the visual recognition through the adhesive sheet is reduced, and sometimes the appearance design, the beauty, and the high-class feeling possessed by the surface of the adherend are impaired.

[0006] While not particularly limited, as one use in which it is desired to have a highly smooth adhesive surface, the following use can be cited: attaching a film in which a design including a specific color tone such as a metallic color tone is implemented to the inner side of a transparent case constituting a portable electronic device, so that the design formation surface (decorative surface) thereof becomes the transparent case side. With respect to the adhesive sheet used for the fixation of the above-described transparent case and film, since both adhesive surfaces can affect visual recognition, it is desirable that both adhesive surfaces have high smoothness. Even with an adhesive sheet having a smoothness that has been considered to be a level of acceptance in the past, optical distortion and the like are observed under more highly accurate evaluation conditions, and it cannot necessarily be said that the surface smoothness thereof is at a satisfactory level. If an adhesive sheet having an adhesive surface with higher smoothness can be achieved, it is practically advantageous as a joining means that does not impair the design, beauty, and high-class feel of the adherend.

[0007] The present application was made in view of the above-described circumstances, and aims to provide an adhesive sheet having an adhesive surface with high surface smoothness in a state protected by a release film.

[0008] According to the present specification, a release film-equipped adhesive sheet is provided. The release film-equipped adhesive sheet has: an adhesive sheet having an adhesive layer, and a release film layered on the adhesive surface of the adhesive sheet. In addition, the maximum height Rz of the adhesive surface side surface of the aforementioned release film is 400 nm or less.

[0009] According to the above-described configuration, the adhesive surface of the adhesive sheet is protected by the release film in a state in contact with the surface of the release film having a maximum height Rz of 400 nm or less, and thus has high surface smoothness. Therefore, when attached to an adherend, the adhesive surface has high surface smoothness with respect to the adherend, and adhesive bonding without optical distortion or with optical distortion suppressed can be achieved.

[0010] In some preferred modes, the arithmetic average roughness Ra of the aforementioned surface of the aforementioned release film is 30 nm or less. According to this configuration, a configuration in which the adhesive surface has high surface smoothness can be preferably achieved.

[0011] In some preferred modes, the release force of the aforementioned release film with respect to the aforementioned adhesive sheet is 1 N / 50 mm or less. With this configuration, when the release film is removed from the adhesive surface at the time of use of the adhesive sheet, fine corrugations of the adhesive surface based on so-called stick-slip phenomena caused by release from the release film are suppressed, and thus a smoother adhesive surface is easily obtained.

[0012] In several preferred embodiments, the aforementioned release film has a thickness in the range of 50 to 125 μm. With such a configuration, the release film has a sufficient thickness, and it is possible to prevent an event (dishing) in which the smoothness of the adhesive sheet surface is damaged beyond the release film. Such an event can be caused by a foreign object interposed between the release films when the adhesive sheet with the release film is taken up into a roll, for example. In addition, by setting the thickness of the release film to a value below the prescribed value, removal of the adhesive sheet becomes smooth, and the adhesive surface of the adhesive sheet also easily maintains a high surface smoothness after the release film is removed.

[0013] In several preferred embodiments, the aforementioned adhesive sheet has a total light transmittance of 85% or more and a haze value of 1% or less. With the adhesive sheet satisfying the aforementioned characteristics, it is easy to visually recognize the adherend through the adhesive sheet without impairing the visual recognition of the appearance design or the like possessed by the adherend.

[0014] In several embodiments, the aforementioned adhesive sheet is a single-coated adhesive sheet having the aforementioned adhesive layer and a support substrate laminated on one face of the adhesive layer. The effects obtained by the technology disclosed herein can be preferably achieved in the embodiments in which the single-coated adhesive sheet is used. In this embodiment, the support substrate can be a transparent substrate.

[0015] In other several embodiments, the aforementioned adhesive sheet is a double-coated adhesive sheet having a first adhesive face and a second adhesive face. In addition, in the adhesive sheet with the release film, as the release film, there are a first release film disposed on the aforementioned first adhesive face and a second release film disposed on the aforementioned second adhesive face. Furthermore, the maximum height Rz1 of the aforementioned first adhesive face side surface S1 of the aforementioned first release film and the maximum height Rz2 of the aforementioned second adhesive face side surface S2 of the aforementioned second release film are each 400 nm or less. In this configuration as well, the effects obtained by the technology disclosed herein can be preferably achieved. In this configuration, it is preferable that the arithmetic mean roughness Ra1 of the aforementioned surface S1 of the aforementioned first release film and the arithmetic mean roughness Ra2 of the aforementioned surface S2 of the aforementioned second release film are each 30 nm or less. In addition, the release force of the aforementioned first release film with respect to the aforementioned adhesive sheet and the release force of the aforementioned second release film with respect to the aforementioned adhesive sheet can each be 1 N / 50 mm or less. Furthermore, the thickness of the aforementioned first release film and the thickness of the aforementioned second release film can each be in the range of 50 to 125 μm.

[0016] In some other embodiments, the aforementioned adhesive sheet is a double-sided adhesive sheet having a first adhesive surface and a second adhesive surface. In addition, the aforementioned release film is a double-sided release film having a first release surface and a second release surface. Furthermore, the maximum height Rz1 of the aforementioned first release surface of the aforementioned release film and the maximum height Rz2 of the aforementioned second release surface of the aforementioned release film are each 400 nm or less. In this configuration, the effects disclosed herein can be preferably achieved. In this configuration, it is preferable that the arithmetic mean roughness Ra1 of the aforementioned first release surface and the arithmetic mean roughness Ra2 of the aforementioned second release surface are each 30 nm or less. In addition, the release force of the aforementioned first release surface with respect to the aforementioned adhesive sheet and the release force of the aforementioned second release surface with respect to the aforementioned adhesive sheet can each be 1 N / 50 mm or less.

[0017] In some preferred embodiments, the aforementioned adhesive layer is an acrylic adhesive layer. When an acrylic adhesive is used, it is possible to achieve the target adhesive properties, viscoelastic properties excellent in impact resistance, without using an additive ingredient such as a softening agent that can be a cause of reduction in transparency, or limiting the amount of additive, thus easily achieving both transparency and adhesive properties, viscoelastic properties. In addition, acrylic adhesives have a tendency to be excellent in color change resistance compared to, for example, rubber-based adhesives, and are also advantageous from the viewpoint of maintaining transparency over a long period of time.

[0018] In some preferred embodiments, the gel fraction of the aforementioned adhesive layer is 30 to 95% by weight. By making the gel fraction of the adhesive layer 95% by weight or less, the adhesive sheet has a tendency to be excellent in height difference followability. Thus, it is possible to adhere to a surface of an adherend having a height difference. For example, in the case where a print such as a mark is formed on the surface of the adherend, the adhesive sheet is able to follow the unevenness of the print well without impairing visual recognition. In addition, by making the gel fraction of the adhesive layer 30% by weight or more, there is a tendency to easily achieve good adhesive properties, viscoelastic properties. For example, when a configuration is employed in which the adhesive layer has the aforementioned gel fraction, there is a tendency to be less likely to cause dents, and also excellent in deformation resistance.

[0019] In some preferred embodiments, the storage modulus at 25°C of the aforementioned adhesive layer is 4 x 10 4 Pa or more. The adhesive layer having the aforementioned storage modulus at 25°C has a tendency to have preferable heat resistance, and easily achieves good adhesive properties such as deformation resistance.

[0020] In some preferred embodiments, the thickness of the aforementioned adhesive sheet is 5 to 100 μm. The adhesive sheet having a thickness of 5 μm or more has a tendency to be excellent in height difference followability, and easily absorbs deformation caused by foreign matter or the like. In addition, by making the aforementioned thickness 100 μm or less, the adhesive sheet is less likely to be strained, and high adhesive surface smoothness is easily achieved.

[0021] In some preferred embodiments, the aforementioned adhesive sheet has an elastic modulus of 3.0 MPa or more as determined by the following tensile test. By satisfying the aforementioned characteristics, the adhesive sheet can exhibit high resistance to deformation.

[0022] [Tensile test]

[0023] For the aforementioned adhesive sheet, the adhesive layer was irradiated with ultraviolet rays under conditions of an irradiance of 300 mW / cm 2 , a cumulative light amount of 3000 mJ / cm 2 , and was allowed to cure for 48 hours at 50°C, and then the aforementioned adhesive layer was cut into a size of 10 mm in width and 150 mm in length, thereby producing a test piece. A tensile test of the aforementioned test piece was performed using a tensile testing machine under conditions of a chuck distance of 120 mm and a tensile speed of 50 mm / minute in an environment of 23°C and 50% RH, and a stress-displacement curve was obtained, from which an elastic modulus [MPa] was calculated.

[0024] In some preferred embodiments, the aforementioned adhesive sheet has an impact resistance of 2.0 J / 10 mm 2 or more as determined by the following shear impact test. By satisfying the aforementioned characteristics, the adhesive sheet can exhibit high impact resistance. For example, an adhesive sheet that satisfies the modulus characteristics based on the aforementioned tensile test and the impact resistance characteristics described above can be preferably used for the purpose of joining and fixing of members, for example, because it has high resistance to deformation and can form a joint with high impact resistance.

[0025] [Shear impact test]

[0026] A shear impact test was performed using a pendulum-type adhesive shear impact testing machine based on JIS K6855. As a measurement sample, a sample obtained by the following procedure was used: the first face of a 10 mm square of the aforementioned adhesive sheet was attached to the central portion of a 25 mm square chemical-strengthened glass plate having a thickness of 1.7 mm, and then the second face of the aforementioned adhesive sheet was attached to the central portion of a 40 mm square stainless steel plate (SUS304BA plate) with a 10-second press bonding at a load of 5 N, followed by autoclave treatment (50°C, 0.5 MPa, 15 minutes), and then the sample was obtained by irradiating the aforementioned glass plate side with ultraviolet rays under conditions of an irradiance of 300 mW / cm 2 , a cumulative light amount of 3000 mJ / cm 2 , and then allowing it to cure for 48 hours at 50°C.

[0027] The aforementioned measurement sample was fixed with the aforementioned stainless steel plate as the lower side, and the absorbed energy [J] when a hammer was struck against the outer peripheral side face of the aforementioned glass plate at a hammer energy of 2.75 J and a hammer speed of 3.5 m / sec was measured in an environment of 23°C and 50% RH, thereby calculating the impact resistance [J / 10 mm 2].

[0028] In several preferred modes, the aforementioned adhesive layer contains the polymer (A) and the photoreactive monomer (B). Further, more preferably, the aforementioned photoreactive monomer (B) comprises a compound B1 having a ring structure and 2 or more ethylenically unsaturated groups in the molecule, the molecular weight of the compound B1 being 100 g / mol or more per 1 ethylenically unsaturated group. With the adhesive sheet having the aforementioned adhesive layer, the resistance to deformation is high and the joining with high impact resistance can be suitably formed.

[0029] With the adhesive sheet with a release film disclosed herein, an adhesive sheet in which both of the adhesive surfaces have high surface smoothness can be realized, and thus is preferably used for a use of fixing a member having an image display surface, a decorative surface, or a colored surface, which often requires high visual recognition, to a transparent member. For example, in a mode of fixing a decorative surface of a decorative film to a transparent member, and the like, the adhesive sheet suppresses optical distortion, and thus the decorative surface is easily visually recognized through the adhesive sheet, and can function as a joining means which does not impair the appearance design, the beauty, and the high-class feeling of the decorative surface.

[0030] The adhesive sheet with a release film disclosed herein can be provided in the form of an adhesive sheet with a release film roll in which the adhesive sheet with a release film is wound. Such a roll is easy to handle at the time of storage and transportation, and is also advantageous in terms of productivity. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 A cross-sectional view of an adhesive sheet with a release film of an embodiment is shown.

[0032] Figure 2 A cross-sectional view of an adhesive sheet with a release film of another embodiment is shown. DETAILED DESCRIPTION

[0033] Suitable embodiments of the present application are described below. Note that matters other than those specifically mentioned in this specification and matters necessary for the implementation of the present application can be understood by those skilled in the art from the teachings of the present specification regarding the implementation of the application and the technical common sense at the time of filing. The present application can be implemented in accordance with the content disclosed in the present specification and the technical common sense in the field. In addition, in the following drawings, sometimes the same symbol is given to members / positions that function in the same manner to describe them, and sometimes repeated descriptions are omitted or simplified. In addition, the embodiments described in the drawings are schematically shown for the purpose of clearly illustrating the present application, and do not necessarily accurately show the dimensions, scales of actually provided products.

[0034] In the present specification, "adhesive" means a material having a property of being easily adhered to an adherend by pressure, in a state of a soft solid (a viscoelastic body) exhibiting softness in a temperature range around room temperature, as described above. The adhesive as referred to herein can be generally a material satisfying the complex modulus E * (1 Hz) < 10 7 dyne / cm 2 a property of satisfying the complex modulus E

[0035] In the present specification, "acrylic polymer" means a polymer derived from a monomer component containing more than 50% by weight of an acrylic monomer, and is also referred to as an acrylic polymer. The acrylic monomer as referred to above means a monomer having at least one (meth)acryloyl group in one molecule. In addition, in the present specification, "(meth)acryloyl group" means a generic term for acryloyl group and methacryloyl group. Similarly, "(meth)acrylate" means a generic term for acrylate and methacrylate; and "(meth)acrylic acid" means a generic term for acrylic acid and (meth)acrylic acid.

[0036] Note that in the present specification, "mass" and "weight" have the same meaning.

[0037] In the present specification, "photoreactive monomer" means a compound having at least one functional group (photoreactive functional group) which can be reacted by light irradiation in the molecule, and a representative example thereof is a compound having at least one ethylenic unsaturated group as the photoreactive functional group in the molecule. The photoreactive monomer as referred to herein can be a polymer such as an oligomer, a polymer (e.g., a polymer having at least one ethylenic unsaturated group in the molecule) itself as long as it can be reacted as a monomer.

[0038] In addition, in the present specification, "photocurability" means a property of being cured by light irradiation such as ultraviolet rays, and for example, a photocurable adhesive composition means a composition which is cured by photocuring to become an adhesive, an adhesive layer. In addition, a photocurable adhesive layer means an adhesive layer which can be cured by light irradiation such as ultraviolet rays, and is used as a term meaning an adhesive layer before photocuring treatment of an adhesive layer which is completely cured by the photocuring treatment. A photocurable adhesive sheet is used as a term meaning an adhesive sheet provided with such a photocurable adhesive layer.

[0039] <Example of configuration of adhesive sheet with release film>

[0040] An example of the constitution of the adhesive sheet with release film disclosed herein will be described below. Figure 1 The adhesive sheet with release film 1 has a double-sided adhesive sheet 10, a first release film 21, and a second release film 22. The adhesive sheet 10 has a first adhesive surface 10a and a second adhesive surface 10b on the opposite side of the first adhesive surface 10a. The adhesive sheet 10 of this embodiment is a double-sided adhesive sheet without a substrate composed of an adhesive layer 12, and thus the first adhesive surface 10a and the second adhesive surface 10b are a first surface 12a and a second surface 12b of the adhesive layer 12, respectively. The first release film 21 is disposed on the first adhesive surface 10a of the adhesive sheet 10, and one surface (first adhesive surface side surface S1) 21a thereof is in contact with the first adhesive surface 10a of the adhesive sheet 10 in a releasable manner. The second release film 22 is disposed on the second adhesive surface 10b of the adhesive sheet 10, and one surface (second adhesive surface side surface S2) 22a thereof is in contact with the second adhesive surface 10b of the adhesive sheet 10 in a releasable manner. The first adhesive surface side surface (S1) 21a of the first release film 21 and the second adhesive surface side surface (S2) 22a of the second release film 22 are release surfaces having a release treatment layer based on, for example, a silicone-based release treatment agent or the like. In this way, the adhesive sheet with release film 1 is in a state in which the first adhesive surface 10a and the second adhesive surface 10b of the adhesive sheet 10 are protected by the first release film 21 and the second release film 22, respectively. In addition, in use of the adhesive sheet 10, the first release film 21 and the second release film 22 are removed, and the first adhesive surface 10a and the second adhesive surface 10b are exposed and attached to an adherend.

[0041] In addition, the adhesive sheet with release film 1 can be in the form of a roll (adhesive sheet with release film roll) 100 as shown in Figure 1 . The adhesive sheet roll 100 is in a state in which the adhesive sheet with release film 1 is wound around a core (winding core) 50.

[0042] The structure of the adhesive sheet with release film of another embodiment will be schematically shown in Figure 2 . Figure 2The illustrated adhesive sheet 2 with a release film has a single-sided adhesive sheet (single-sided adhesive sheet) 10 and a release film 21. The single-sided adhesive sheet 10 has an adhesive layer 12 and a support substrate 14 that supports the adhesive layer 12, one face (first face 12a of the adhesive layer 12) of which becomes an adhesive face 10a, and the other face becomes a back face (non-adhesive face). In this embodiment, the back face of the adhesive sheet 10 is composed of one face (face 14b of the support substrate 14 on the side opposite the adhesive layer side surface 14a) of the support substrate 14. The second face 12b of the adhesive layer 12 is fixed to the other face (adhesive layer side surface) 14a of the support substrate 14, and the adhesive layer side surface 14a can be said to be a non-releasable surface (non-releasing face). In this way, the adhesive layer 12 is provided in a manner not intended to be separated from the support substrate 14. On the other hand, the surface (adhesive face side surface S1) 21a of the release film 21 is in contact with the adhesive face 10a of the adhesive layer 12 in a releasable manner, and protects the adhesive face 10a. This adhesive sheet 2 with a release film can also be provided in the form of a roll body (adhesive sheet roll) 200 as illustrated. Figure 1 the first release film becomes a releasing face in the same manner, is in contact with the adhesive face 10a of the adhesive layer 12 in a releasable manner, and protects the adhesive face 10a. This adhesive sheet 2 with a release film can also be provided in the form of a roll body (adhesive sheet roll) 200 as illustrated. Figure 2 The illustrated roll body (adhesive sheet roll) 200 is in the form of a roll body in which the adhesive sheet 2 with a release film, which has the adhesive sheet 10 having the adhesive layer 12 and the support substrate 14, and the release film 21, is wound around a core (roll core) 50.

[0043] Note that, Figure 1 The roll body 100 is illustrated in the form of a roll body in which the adhesive sheet 1 with a release film is wound around the core 50, but the roll body 100 can also be in the form of a so-called coreless roll body in which the adhesive sheet 1 with a release film is wound alone without the core 50. For example, Figure 2 The illustrated roll body 200 is also the same.

[0044] In addition, Figure 1 The adhesive sheet 1 (before use) illustrated has a configuration in which the first adhesive face 10a and the second adhesive face 10b are protected by the first release film 21 and the second release film 22, respectively, at least the adhesive face side of which has a releasing face, but a configuration in which the second release film 22 is omitted, a film in which both faces are releasing faces is used as the release film 21, and the second adhesive face 10b is brought into contact with the back face of the release film 21 when the adhesive sheet 1 is wound, so that the second adhesive face 10b is also protected by the release film 21, can also be adopted.

[0045] In addition, the adhesive sheet can be a substrate-free adhesive sheet as illustrated, and can also be a substrate-free adhesive sheet as illustrated. Figure 1 Figure 2 ​The single-faced adhesive sheet with a substrate as shown can further be in the form of a double-faced adhesive sheet with a substrate. Specifically, the adhesive sheet can be a substrate-containing adhesive sheet with a non-peeling substrate built-in (embedded). As the substrate, a plastic film, paper, non-woven fabric, or the like can be used. Further, Figure 1 , 2 The adhesive layer 10 is exemplified as a single-layer structure, but the configuration of the adhesive layer 10 is not limited thereto. For example, the adhesive layer can be configured to include two or more sub-adhesive layers formed of the same or different adhesive.

[0046] <Peeling film>

[0047] (Maximum height Rz of adhesive surface side surface)

[0048] The maximum height Rz of the adhesive surface side surface of the peeling film disclosed herein is 400 nm or less. Thereby, the adhesive surface of the adhesive sheet can have high surface smoothness. In addition, in the form in which the first peeling film and the second peeling film are respectively disposed on each of the adhesive surfaces of the adhesive sheet, the maximum height Rz1 of the first adhesive surface side surface S1 of the first peeling film and the maximum height Rz2 of the second adhesive surface side surface S2 of the second peeling film are each 400 nm or less. Thereby, each of the adhesive surfaces of the double-faced adhesive sheet has high surface smoothness, and both of the adhesive surfaces can exhibit high surface smoothness when adhered to an adherend.

[0049] The maximum height Rz of the adhesive surface side surface of the peeling film (including the maximum height Rz1 of the first adhesive surface side surface S1 of the first peeling film and the maximum height Rz2 of the second adhesive surface side surface S2 of the second peeling film. The same applies hereinafter in the absence of specific description.) is preferably about 340 nm or less, more preferably about 280 nm or less, and further preferably about 240 nm or less, and can be less than 200 nm, less than 150 nm, or less than 120 nm. In addition, from the viewpoints of ease of manufacture, handleability, and the like of the peeling film, in some modes, the above maximum height Rz can be about 50 nm or more, about 80 nm or more, or about 100 nm or more. In the mode in which the first peeling film and the second peeling film are provided, the maximum height Rz1 of the first adhesive surface side surface S1 of the first peeling film and the maximum height Rz2 of the second adhesive surface side surface S2 of the second peeling film can be the same level or different.

[0050] (Arithmetic mean roughness Ra of adhesive surface side surface)

[0051] Further, with respect to the release film, from the viewpoint of achieving an adhesive surface having high surface smoothness, it is preferable that the arithmetic mean roughness Ra of the surface on the adhesive surface side be limited to a prescribed value or less (for example, about 100 nm or less, further 50 nm or less). Further, in a form in which the first release film and the second release film are respectively arranged on each of the adhesive surfaces of the adhesive sheet, it is appropriate that the arithmetic mean roughness Ra1 of the surface S1 of the first release film and the arithmetic mean roughness Ra2 of the surface S2 on the second adhesive surface side of the second release film be limited to about 100 nm or less (further 50 nm or less). Among several modes, the arithmetic mean roughness Ra of the surface on the adhesive surface side of the release film (including the arithmetic mean roughness Ra1 of the surface S1 on the first adhesive surface side of the first release film and the arithmetic mean roughness Ra2 of the surface S2 on the second adhesive surface side of the second release film. The same applies hereinafter in the absence of a specific description.) is preferably about 30 nm or less, can be about 25 nm or less, can be about 20 nm or less, and can be about 18 nm or less. Further, from the viewpoints of ease of manufacture, handleability, and the like of the release film, among several modes, the above arithmetic mean roughness Ra can be about 5 nm or more, can be about 10 nm or more, and can be about 15 nm or more. In the mode in which the first release film and the second release film are provided, the arithmetic mean roughness Ra1 of the surface S1 on the first adhesive surface side of the first release film and the arithmetic mean roughness Ra2 of the surface S2 on the second adhesive surface side of the second release film can be at the same level or can be different.

[0052] (Surface properties of the back surface)

[0053] The maximum height Rz and the arithmetic mean roughness Ra of the back surface (the opposite surface of the adhesive layer side) of the release film (including the first release film and the second release film) are not particularly limited. The maximum height Rz of the back surface (the opposite surface of the adhesive layer side) of the release film can be more than 400 nm (for example, about 500 nm or more) from the viewpoint of productivity and the like, and can be more than 800 nm (for example, 1000 nm or more). The arithmetic mean roughness Ra of the back surface (the opposite surface of the adhesive layer side) of the release film can be more than 30 nm (for example, more than 35 nm, further about 50 nm or more) from the viewpoint of productivity and the like.

[0054] The maximum height Rz and the arithmetic mean roughness Ra of the surface of the release film can be adjusted by selection of the film material, the molding method, surface treatment such as release treatment, and the like. For example, adjustment of the smoothness of the layer (anti-blocking layer, hard coat layer, oligomer preventive layer, and the like) constituting the release surface; reduction or non-use (particle-free) of the filler particles in the surface layer and the release film substrate; and adjustment of the stretching conditions, and the like can be cited.

[0055] The maximum height Rz and the arithmetic average roughness Ra of the surface of the release film were measured using a non-contact surface roughness measuring device. As the non-contact surface roughness measuring device, a surface roughness measuring device of an optical interference type, such as a three-dimensional optical profiler (trade name "NewView7300", manufactured by ZYGO Corporation) or the like can be used. For example, a glass plate (soda-lime glass plate, manufactured by MATSUNAMI, thickness: 1.3 μm) was attached and fixed to the surface of the release film on the side opposite to the measurement surface with an adhesive, and the surface shape was measured using a three-dimensional optical profiler (trade name "NewView7300", manufactured by ZYGO Corporation) in an environment of 23°C and 50% RH. The same was also applied in the examples described later. The measurement conditions and the calculation method were the same as those for the maximum height Rz and the arithmetic average roughness Ra of the adhesive surface of the adhesive sheet described later.

[0056] The release film (including the first release film and the second release film. The same applies hereinafter in the absence of a specific description.) can be selected so as to have a maximum height Rz of the surface on the adhesive surface side of 400 nm or less. Non-limiting examples of the release film that can be used include a release film having a release treatment layer on the surface of a release film substrate, and a release film formed of a low-adhesion resin of a fluorine-based polymer (polytetrafluoroethylene or the like), a polyolefin-based resin (polyethylene, polypropylene or the like).

[0057] As the release film disclosed herein, a release film having a release treatment layer on a release film substrate can be preferably used. The release treatment layer can be formed by surface treatment of the release film substrate with a release treatment agent. The release treatment agent can be a known release treatment agent such as a silicone-based release treatment agent, a long-chain alkyl-based release treatment agent, a fluorine-based release treatment agent, molybdenum (IV) sulfide or the like. Among these, a release film having a release treatment layer based on a silicone-based release treatment agent is preferably used. The thickness and the formation method of the release treatment layer are not particularly limited and can be set in a manner that imparts appropriate release properties to the surface on the adhesive surface side of the release film.

[0058] As the release film substrate, various plastic films can be used. In the present specification, the plastic film represents a non-porous sheet and is a concept that is distinguished from, for example, a nonwoven fabric (i.e., does not include a nonwoven fabric).

[0059] As the material of the above-mentioned plastic film, for example, polyester-based resins such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polyolefin-based resins such as polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-butene copolymer, cellulose resins such as triacetyl cellulose, acetate-based resins, polysulfone-based resins, polyethersulfone-based resins, polycarbonate-based resins, polyamide-based resins, polyimide-based resins, cyclic polyolefin resins such as norbornene-based resins, (meth)acrylic-based resins, polyvinyl chloride-based resins, polyvinylidene chloride-based resins, polystyrene-based resins, polyvinyl alcohol-based resins, ethylene-vinyl acetate copolymer resins, ethylene-vinyl alcohol copolymer resins, polyarylate-based resins, and polyphenylene sulfide-based resins can be exemplified. A release film substrate formed of any one of these resins or a mixture of two or more of these resins can be used. As a preferable release film substrate therefrom, a polyester-based resin film (for example, a PET film) formed of a polyester-based resin can be exemplified.

[0060] The plastic film used as the above-mentioned release film substrate can be any one of an unstretched film, a uniaxially stretched film, and a biaxially stretched film. In addition, the above-mentioned plastic film can be a single layer structure or a multi-layer structure including two or more sub-layers. In the above-mentioned plastic film, known additives for a release film substrate of an adhesive sheet such as an antioxidant, an anti-aging agent, a heat-resistant stabilizer, a light stabilizer, an ultraviolet absorber, a coloring agent such as a pigment or a dye, a lubricant, a filler, an antistatic agent, a nucleating agent can be compounded. In a multi-layer structure plastic film, each additive can be compounded in all sub-layers or only in a part of the sub-layers.

[0061] In some preferable modes, as the above-mentioned release film substrate (representatively, a plastic film), a release film substrate in which the content of particles such as inorganic particles (for example, a pigment, a lubricant, a filler, and the like) in the layer on the release surface side is limited or substantially free from such particles can be preferably used. Here, substantially free means that the amount of particles (for example, inorganic particles) in the layer is less than 1% by weight, preferably less than 0.1% by weight (for example, 0 to 0.01% by weight). For a release film having such a release film substrate, the maximum height Rz of the release surface and the arithmetic mean roughness Ra are easily low. In the case where the above-mentioned release film substrate (representatively, a plastic film) has a multi-layer structure, the content of particles in the layer on the release surface side can be 1 / 10 or less (for example, 1 / 50 or less) of the content of particles in the layer other than the layer on the release surface side.

[0062] In the mode in which the first release film and the second release film are provided, the first release film and the second release film can have the same material and constitution or different materials and constitution.

[0063] The thickness of the release film is not particularly limited, and can be, for example, about 10 μm to 500 μm. From the viewpoint of the strength and dimensional stability of the release film, it is appropriate for the thickness of the release film to be 20 μm or more, and preferably 30 μm or more, and can be 35 μm or more, 40 μm or more, or 45 μm or more. In some preferred embodiments, the thickness of the release film is about 50 μm or more, and can be about 60 μm or more, or about 70 μm or more. Thus, the release film has a sufficient thickness, and can prevent the occurrence of events (dents) that damage the smoothness of the surface of the adhesive sheet beyond the release film. In addition, from the viewpoint of the handling properties (e.g., ease of winding) of the release film, it is appropriate for the thickness of the release film to be 300 μm or less, and preferably 250 μm or less, and can be 200 μm or less, 150 μm or less, or 130 μm or less. In some preferred embodiments, the thickness of the release film is about 125 μm or less, and can be about 115 μm or less, or about 105 μm or less, or about 90 μm or less. By setting the thickness of the release film to be a prescribed value or less, the occurrence of winding marks when the release film is made into a roll becomes less likely, the removal of the adhesive sheet becomes easier, and the adhesive surface of the adhesive sheet is also likely to maintain a high surface smoothness after the release film is removed.

[0064] In the embodiment in which the first release film and the second release film are provided, the thickness of the first release film and the second release film can be the same or different. From the viewpoint of the ease of release operation, it is preferable for the first release film and the second release film to have different thicknesses, and it is preferable for the thickness of the thicker one of the release films to be about 1.1 times or more, for example, about 1.25 times or more, the thickness of the thinner one of the release films.

[0065] Note that, on the back surface of the release film, a film for a carrier or an auxiliary film can be attached as needed. By the presence of such a back surface auxiliary film, it is easy to prevent dents, for example, in the case of using a release film having a thin thickness, and the operability of punching processing and the like can be improved. As such a back surface auxiliary film, a publicly known or conventional adhesive tape having a resin film substrate can be used.

[0066] <Release Force of Release Film>

[0067] The adhesive sheet with a release film disclosed herein is preferably such that the peeling force of the release film against the adhesive sheet is limited to a value or less. Thus, when the release film is removed from the adhesive face at the time of use of the adhesive sheet, the fine corrugation of the adhesive face based on the so-called stick-slip phenomenon caused by peeling from the release film is suppressed, and a smoother adhesive face is easily obtained. In several preferred modes, the peeling force of the above-mentioned release film is about 1 N / 50 mm or less, more preferably less than 0.90 N / 50 mm, further preferably less than 0.70 N / 50 mm, particularly preferably less than 0.50 N / 50 mm, can be less than 0.40 N / 50 mm, can be less than 0.30 N / 50 mm, can be less than 0.20 N / 50 mm, and can be less than 0.10 N / 50 mm. The lower limit value of the peeling force of the above-mentioned release film is, for example, 0.01 N / 50 mm or more, and from the viewpoint of the protective property based on the release film and the prevention of floating, can be 0.05 N / 50 mm or more. The peeling force of the release film can be adjusted by peeling treatment or the like on the surface of the release film.

[0068] In the mode having the first release film and the second release film, from the viewpoint of the peeling operability, it is preferable that the peeling force of the first release film against the adhesive sheet and the peeling force of the second release film against the adhesive sheet are different. For example, it is appropriate that the peeling force of the release film on the heavy peeling side (for example, the second release film) is about 1.2 times or more, preferably about 1.4 times or more, can be about 1.5 times or more, and can be about 1.8 times or more, of the peeling force of the release film on the light peeling side (for example, the first release film). From the viewpoint of maintaining the light peeling property, it is appropriate that the peeling force of the release film on the heavy peeling side (for example, the second release film) is about 3 times or less, and can be about 2 times or less, of the peeling force of the release film on the light peeling side (for example, the first release film).

[0069] The peeling force of the release film is measured as follows: an adhesive sheet with a release film cut to a length of 150 mm and a width of 50 mm is prepared, and measurement is performed at 23°C and 50% RH in an atmosphere, at a stretching speed of 300 mm / minute, and at a peeling angle of 180°. Specifically, measurement is performed by the method described in the Examples below.

[0070] <ADHESIVE SHEET>

[0071] (Surface properties of the adhesive face)

[0072] The adhesive sheet disclosed herein has an adhesive surface with a maximum height Rz limited to a prescribed value or less. With the adhesive surface designed to have a low maximum height Rz, the adhesive sheet can have high surface smoothness, and can become free of optical distortion or have optical distortion suppressed. In the case of, for example, visually recognizing the surface of an adherend through the adhesive sheet, the adhesive sheet can become free of impairment of the appearance design, such as the beauty or elegance, of the adherend. In the case of the adhesive sheet being in the form of a double-sided adhesive sheet having adhesive surfaces on both sides, it is appropriate for the maximum height Rz of the first adhesive surface and the second adhesive surface constituting the double-sided adhesive sheet to be limited to a prescribed value or less. With each adhesive surface of the double-sided adhesive sheet having high surface smoothness, the adhesive sheet can achieve bonding free of optical distortion or having optical distortion highly suppressed. For example, in the case of an adherend having a transparent member on one side and an appearance design on the other side, the appearance design of the adherend can be visually recognized well through the adhesive sheet.

[0073] The maximum height Rz of the adhesive surface (including the first adhesive surface and the second adhesive surface. The same applies hereinafter in the absence of a specific description.) of the adhesive sheet is preferably about 600 nm or less, more preferably about 500 nm or less, further preferably about 450 nm or less, particularly preferably about 400 nm or less, and can be less than 350 nm, less than 300 nm, or less than 250 nm. From the viewpoint of production efficiency and the like, among several modes, the maximum height Rz of the adhesive surface of the adhesive sheet may, for example, be about 10 nm or more, about 50 nm or more, about 100 nm or more, or about 200 nm or more. In the case of the adhesive sheet having a first adhesive surface and a second adhesive surface, the maximum height Rz of the first adhesive surface and the maximum height Rz of the second adhesive surface can be the same or different.

[0074] The adhesive surface of the adhesive sheet disclosed herein preferably has an arithmetic mean roughness Ra limited to a prescribed value or less. With the adhesive surface designed to have a low arithmetic mean roughness Ra, optical distortion can be highly suppressed. In the case of the adhesive sheet being in the form of a double-sided adhesive sheet having adhesive surfaces on both sides, it is appropriate for the arithmetic mean roughness Ra of the first adhesive surface and the second adhesive surface constituting the double-sided adhesive sheet to be limited to a prescribed value or less. With each adhesive surface of the double-sided adhesive sheet having high surface smoothness, the adhesive sheet can preferably achieve bonding free of optical distortion or having optical distortion highly suppressed.

[0075] The arithmetic average roughness Ra of the adhesive surface of the adhesive sheet is preferably about 70 nm or less, more preferably about 65 nm or less, further preferably about 55 nm or less, can be less than 50 nm, can be less than 45 nm, or can be less than 40 nm. From the viewpoint of production efficiency and the like, among several modes, the arithmetic average roughness Ra of the adhesive surface of the adhesive sheet can be, for example, about 10 nm or more, can be about 20 nm or more, or can be about 30 nm or more (for example, about 40 nm or more). In the mode in which the adhesive sheet has a first adhesive surface and a second adhesive surface, the arithmetic average roughness Ra of the first adhesive surface and the arithmetic average roughness Ra of the second adhesive surface can be the same level or can be different.

[0076] Note that the maximum height Rz and the arithmetic average roughness Ra of the adhesive surface of the adhesive sheet can be adjusted by the surface properties of the release film stacked on the adhesive surface, the peeling force of the release film from the adhesive sheet, the thickness of the adhesive layer, and the like.

[0077] In addition, the maximum height Rz of the adhesive surface of the above-described adhesive sheet can be the maximum height Rz of the surface of the adhesive layer constituting the adhesive sheet. Similarly, the arithmetic average roughness Ra of the adhesive surface of the above-described adhesive sheet can be the arithmetic average roughness Ra of the surface of the adhesive layer constituting the adhesive sheet. Therefore, as the range and value of the maximum height Rz and the arithmetic average roughness Ra of the surface of the adhesive layer, the range and value described as the maximum height Rz and the arithmetic average roughness Ra of the adhesive surface of the above-described adhesive sheet can be used, respectively.

[0078] In addition, the maximum height Rz and the arithmetic average roughness Ra of the adhesive surface of the adhesive sheet are measured as follows: for the adhesive surface of the adhesive sheet after the release film is peeled from the adhesive sheet with the release film, a non-contact surface roughness measuring device is used for measurement. As the non-contact surface roughness measuring device, a surface roughness measuring device of an optical interference type is used, and for example, a three-dimensional optical profilometer (trade name "NewView7300", manufactured by ZYGO Corporation) or the like can be used. The specific measurement operation and measurement conditions can be set in accordance with the measurement conditions described in the examples described below, or in a manner that enables results equivalent to or corresponding to the case in which the measurement conditions are followed.

[0079] (Overall light transmittance)

[0080] In some embodiments, the total light transmittance of the adhesive sheet is, for example, about 50% or more, and is, for example, about 70% or more. From the viewpoint of visual recognition of the adherend through the adhesive sheet, in some preferred embodiments, the total light transmittance of the adhesive sheet is about 85% or more, and is more preferably about 90% or more. The upper limit of the total light transmittance is, in theory, a value obtained by subtracting light loss (Fresnel loss) due to reflection at the air interface from 100%, and in practice, can be about 95% or less, or about 94% or less (for example, 93% or less). When the adhesive sheet having such a total light transmittance is used, good visual recognition can be obtained through the adhesive sheet.

[0081] (Haze value)

[0082] In some embodiments, the haze value of the adhesive sheet can be, for example, about 10% or less, and is, for example, about 3% or less. From the viewpoint of visual recognition of the adherend through the adhesive sheet, in some preferred embodiments, the haze value of the adhesive sheet is about 1% or less, and is more preferably about 0.8% or less, and is further preferably 0.5% or less. The lower limit of the haze value is, in theory, 0%, and in practice, can exceed about 0.0%. Note that the "haze value" refers to the proportion of diffuse transmission light with respect to the total transmission light when visible light is irradiated on the measurement object. It is also referred to as the Haze value. The haze value can be represented by the following formula.

[0083] Th[%] = Td / Tt x 100

[0084] In the above formula, Th is the haze value [%], Td is the scattered light transmittance, and Tt is the total light transmittance.

[0085] Note that the total light transmittance and the haze value of the adhesive sheet can be adjusted by the composition (type of base polymer, additive ingredient), thickness, and the like of the adhesive sheet (representatively, the adhesive layer).

[0086] In addition, the total light transmittance of the above-described adhesive sheet can be the total light transmittance of the adhesive layer constituting the adhesive sheet. Similarly, the haze value of the above-described adhesive sheet can be the haze value of the adhesive layer constituting the adhesive sheet. Therefore, as the range and value of the total light transmittance and the haze value of the adhesive layer, the range and value described as the total light transmittance and the haze value of the above-described adhesive sheet can be used, respectively.

[0087] In addition, the total light transmittance and the haze value of the adhesive sheet can be measured by adhering the measurement object of the adhesive sheet to one side of a glass plate, and using a haze meter. As the haze meter, a device manufactured by Murakami Color Research Laboratory, with the device name "HM-150N" or its equivalent can be used. Specifically, the measurement is performed by the method described in the Examples described later.

[0088] The adhesive sheet having the total light transmittance, haze value as described above can be a colored transparent or colorless transparent adhesive sheet. Note that in the present specification, "transparent" is used in a concept including translucent. In addition, the optical distortion reduction effect brought about by the adhesive sheet using the technology disclosed herein can be exerted in a configuration in which at least a part of the adhesive sheet has a transmittance at a level that enables visual recognition through the adhesive sheet, and thus the adhesive sheet need not be transparent or translucent.

[0089] (Glass adhesion)

[0090] The adhesion of the adhesive sheet disclosed herein is not particularly limited and can be set as appropriate according to the purpose. In several modes, the adhesion of the adhesive sheet to a glass plate (glass adhesion) is, for example, preferably about 1.0 N / 20 mm or more, and can be about 3.0 N / 20 mm or more (for example, about 5.0 N / 20 mm or more). From the viewpoint of bonding reliability, the glass adhesion described above is preferably about 7.0 N / 20 mm or more, more preferably about 8.0 N / 20 mm or more, further preferably about 9.0 N / 20 mm or more, can be about 10.0 N / 20 mm or more, and can be about 11.0 N / 20 mm or more. The adhesive sheet having the glass adhesion described above can be preferably used for purposes such as bonding, fixing, and the like of a member. In addition, from the viewpoint of easily achieving a balance with other characteristics, the glass adhesion described above can be, for example, about 20 N / 20 mm or less, about 16.0 N / 20 mm or less, or about 12.0 N / 20 mm or less. The glass adhesion described above can be adjusted by selecting the composition, thickness, and the like of the adhesive layer.

[0091] The glass adhesion is obtained as follows: for the adhesive surface of the measurement object, a 2-kg rubber roller is pressed against a glass plate for one reciprocation, and in an environment at 23°C, 50% RH, the adhesive sheet is peeled from the glass plate at a peeling angle of 180 degrees and a tensile speed of 300 mm / minute using a tensile testing machine in accordance with JIS Z 0237, and the peeling strength at this time is measured, whereby the glass adhesion is obtained. Specifically, the measurement is performed by the method described in the Examples below.

[0092] (Elastic modulus based on tensile test)

[0093] In some preferred embodiments, the adhesive sheet has an elastic modulus based on a tensile test (also referred to as an initial elastic modulus) of 3.0 MPa or more. An adhesive sheet having a higher elastic modulus tends to exhibit better resistance to deformation. An adhesive sheet having a high elastic modulus as described above can be preferably used for purposes such as joining, fixing, and the like of members. For example, in a manner in which two members are joined by means of an adhesive sheet, high resistance to deformation of the adhesive sheet can contribute to maintaining the relative positions of the two members with good precision. In addition, for example, in a manner in which a thin film member and another member are joined by means of an adhesive sheet, high resistance to deformation of the adhesive sheet can contribute to suppressing changes in the appearance of the laminate due to partial pressing from the side of the thin film member (resistance to pressing deformation). In a manner in which the adherend is a rigid member (for example, a glass member) having transparency, it is particularly meaningful to suppress changes in the appearance that are visually recognized from the side of the adherend.

[0094] In some preferred embodiments of the adhesive sheet, the elastic modulus can be, for example, 5.0 MPa or more, 7.0 MPa or more, 10.0 MPa or more, 15.0 MPa or more, or 20.0 MPa or more. There is a tendency for the resistance to deformation to improve as the elastic modulus increases. There is no particular limitation on the upper limit of the elastic modulus. From the viewpoint of easily achieving a balance with other characteristics (for example, one or two or more characteristics selected from the group consisting of impact resistance, adhesion to glass, haze value, and the like), it is advantageous for the elastic modulus to be 150 MPa or less, preferably 120 MPa or less, can be 100 MPa or less, can be 80 MPa or less, can be 60 MPa or less. The elastic modulus based on a tensile test can be adjusted by selection of the composition of the adhesive sheet (representatively, the adhesive layer), and the like. The elastic modulus based on a tensile test is measured by the tensile test described above. More specifically, it is measured by the method described in the Examples below.

[0095] (Impact resistance)

[0096] The adhesive sheet disclosed herein preferably has an impact resistance of 2.0 J / 10 mm 2 or more. When an adhesive sheet having a high impact resistance as described above is used, a joint with high reliability can be formed. This can be an advantageous feature for an adhesive sheet used for purposes such as joining, fixing, and the like of members. The adhesive sheet can withstand an impact such as a drop, a collision, and the like, and maintain the joint of the member and the adherend with good precision.

[0097] In some preferred embodiments of the adhesive sheet, the impact resistance can be, for example, 2.1 J / 10 mm 2 or more, 2.3 J / 10 mm 2 or more, or 2.5 J / 10 mm 2The above, or 2.7 J / 10 mm 2 The above, or 3.0 J / 10 mm 2 The above. The adhesive sheet disclosed herein can also have the impact resistance of 3.3 J / 10 mm 2 The above, or 3.5 J / 10 mm 2 The above, or 3.5 J / 10 mm 2 The above, or 15 J / 10 mm 2 The above, or 10 J / 10 mm 2 The above, or 8.0 J / 10 mm 2 The above, or 6.0 J / 10 mm 2 The above. The impact resistance can be adjusted by selecting the composition, thickness, and the like of the adhesive layer. The impact resistance is measured by the shear impact test described above. More specifically, it is measured by the method described in the Examples below.

[0098] (thickness)

[0099] The thickness of the adhesive sheet is appropriately set depending on the use target and the use method, and is not limited to a particular range. The thickness of the adhesive sheet can be, for example, about 1 μm to 500 μm, or for example, about 3 μm to 500 μm. In some modes, the thickness of the adhesive sheet is preferably 5 μm or more, for example, 10 μm or more, preferably 20 μm or more, more preferably 25 μm or more, or can be more than 25 μm. In the adhesive sheet having a large thickness, optical distortion is easily reduced by the stress dispersion ability of the adhesive layer. In addition, the adhesive sheet having a large thickness has a tendency to have excellent height difference followability, and easily absorbs deformation caused by foreign matter and the like. The impact resistance also has a tendency to be improved. The technology disclosed herein can be preferably implemented in a mode in which the thickness of the adhesive sheet is 30 μm or more. The thickness of the adhesive sheet described above can be 35 μm or more, or 40 μm or more, or 45 μm or more, or 50 μm or more, or 75 μm or more, or 90 μm or more. On the other hand, when the thickness of the adhesive sheet is large, the light path through the adhesive sheet also becomes long, and thus it becomes easy to visually recognize optical distortion. Therefore, in some modes, it is appropriate that the thickness of the adhesive sheet is set to 200 μm or less, for example, 150 μm or less, or 120 μm or less, or 100 μm or less, or 70 μm or less, or 50 μm or less, or 35 μm or less.

[0100] <Adhesive Layer>

[0101] The kind of the adhesive constituting the adhesive layer contained in the adhesive sheet is not particularly limited in the technology disclosed herein. The adhesive layer described above can be, for example, an adhesive layer constituted of one or two or more kinds of adhesives selected from various kinds of adhesives known in the art, such as acrylic adhesives, rubber-based adhesives (natural rubber-based, synthetic rubber-based, mixed ones thereof, etc.), silicone-based adhesives, polyester-based adhesives, urethane-based adhesives, polyether-based adhesives, polyamide-based adhesives, fluorine-based adhesives, etc. Here, the acrylic adhesive refers to an adhesive in which an acrylic polymer is used as a base polymer (a main component among polymer components, i.e., a component having a content of more than 50% by weight). The same applies to the rubber-based adhesive and the other adhesives.

[0102] (Polymer (A))

[0103] Among several modes, the adhesive layer described above contains the polymer (A). As examples of materials that can be used as the polymer (A), there can be listed polymers known in the art of adhesives, such as acrylic polymers, rubber-based polymers, polyester-based polymers, urethane-based polymers, polyether-based polymers, silicone-based polymers, polyamide-based polymers, fluorine-based polymers, etc., which exhibit rubber elasticity in the room temperature range. They can be used alone or in combination of two or more kinds.

[0104] From the viewpoint of the adhesive properties such as impact resistance, it is appropriate that the weight ratio of the polymer (A) in the total weight of the adhesive layer is 40% by weight or more, it is preferable that it is 50% by weight or more, it is more preferable that it is 60% by weight or more, it is further preferable that it is 70% by weight or more, it can be about 80% by weight or more, it can be about 90% by weight or more, and it can be about 97% by weight or more (e.g., about 99% by weight or more). When the adhesive having a high content ratio of the polymer (A) is used, there is a tendency that the transparency is also excellent. In addition, the weight ratio of the polymer (A) in the total weight of the adhesive layer is typically less than 100% by weight, and from the viewpoint of easily adjusting the balance of properties, it is advantageous that it is 95% by weight or less, it is preferable that it is 92% by weight or less, it can be 90% by weight or less, and it can be 87% by weight or less.

[0105] As one preferable example of the polymer (A), an acrylic polymer can be cited. The adhesive layer in the technology disclosed herein can be an acrylic adhesive layer containing an acrylic polymer as a base polymer (a main component among the polymer components, i.e., a component having a content of more than 50% by weight). The acrylic adhesive is preferable from the viewpoints of transparency, weather resistance, and the like, and it is easy to achieve viscoelastic properties excellent in impact resistance without depending on additives such as a softening agent. The acrylic polymer (A) (hereinafter sometimes referred to as "acrylic polymer (A)") is preferably an acrylic polymer composed of a monomer component containing an alkyl (meth)acrylate having a linear or branched alkyl group having 1 or more and 20 or less carbon atoms at the ester terminal in a proportion of 40% by weight or more. Hereinafter, the alkyl (meth)acrylate having an alkyl group having X or more and Y or less carbon atoms at the ester terminal is sometimes referred to as "(meth)acrylic acid C X-Y alkyl ester".

[0106] In some modes, it is appropriate that the proportion of the alkyl (meth)acrylic acid C 1-20 alkyl ester in the entire monomer component of the acrylic polymer (A) is more than 40% by weight, for example, can be 45% by weight or more, can be 50% by weight or more, can be 55% by weight or more, or can be 60% by weight or more. The proportion of the alkyl (meth)acrylic acid C 1-20 alkyl ester in the monomer component can be 100% by weight, but it is appropriate that it is 98% by weight or less, for example, can be 95% by weight or less, or can be 90% by weight or less, from the aspect of easily achieving a balance of properties. In some modes, from the viewpoint of improving the cohesion of the adhesive layer, the proportion of the alkyl (meth)acrylic acid C 1-20 alkyl ester in the entire monomer component of the acrylic polymer (A) can be 85% by weight or less, can be 80% by weight or less, can be 75% by weight or less, can be 70% by weight or less, can be 65% by weight or less, can be 60% by weight or less.

[0107] The alkyl group having 1 or more and 20 or less carbon atoms at the ester terminal of the alkyl (meth)acrylic acid C 1-20Non-limiting specific examples of the alkyl ester include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, t-butyl (meth)acrylate, amyl (meth)acrylate, isoamyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, and the like.

[0108] Among them, at least (meth)acrylic acid C 4-20 alkyl ester is preferably used. More preferably, at least (meth)acrylic acid C 4-18 alkyl ester is used. As particularly preferable (meth)acrylic acid C 4-18 alkyl ester, n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) can be mentioned. As other preferable (meth)acrylic acid C 4-20 alkyl ester, isononyl acrylate, n-butyl methacrylate (BMA), 2-ethylhexyl methacrylate (2EHMA), isostearyl acrylate (iSTA), and the like can be mentioned. These (meth)acrylic acid C 4-20 alkyl esters can be used singly or in combination of two or more.

[0109] The monomer component preferably contains at least one or both of, for example, n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA). In several modes, the monomer component preferably contains at least BA. Here, examples of the monomer component containing at least BA include a monomer component of a composition containing BA and not containing 2EHA, and a monomer component of a composition containing BA and 2EHA and having a content of 2EHA less than that of BA (for example, a content of 2EHA less than 0.5 times or less than 0.3 times the content of BA).

[0110] In several modes, the monomer component constituting the acrylic polymer (A) can contain (meth)acrylic acid C 4-18 alkyl ester in a proportion of 40% by weight or more. The (meth)acrylic acid C 4-18The proportion of the alkyl ester may be, for example, 50% by weight or more, 60% by weight or more, or 65% by weight or more.

[0111] In addition, from the viewpoint of improving the cohesion of the adhesive layer, the monomer component may contain (meth)acrylic acid C 4-18 The proportion of the alkyl ester may be, for example, 50% by weight or more, 60% by weight or more, or 65% by weight or more.

[0112] The monomer component constituting the acrylic polymer (A) may, as needed, contain, together with the alkyl (meth)acrylate, other monomers (copolymerizable monomers) copolymerizable with the alkyl (meth)acrylate. As the copolymerizable monomers, monomers having a polar group (for example, a carboxyl group, a hydroxyl group, a nitrogen atom-containing ring, or the like), monomers having a relatively high glass transition temperature (for example, 10°C or higher) of a homopolymer can be appropriately used. Monomers having a polar group can contribute to the introduction of crosslinking points into the acrylic polymer (A) or the improvement of the cohesion of the adhesive. The copolymerizable monomers can be used alone or in combination of two or more.

[0113] As non-limiting specific examples of the copolymerizable monomers, the following monomers can be given.

[0114] Carboxyl group-containing monomers: for example, acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, and the like.

[0115] Anhydride group-containing monomers: for example, maleic anhydride, itaconic anhydride.

[0116] Hydroxyl group-containing monomers: for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl (meth)acrylate, and the like.

[0117] Monomers containing a sulfonic acid group or a phosphoric acid group: for example, styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, (meth)acrylsulfopropyl ester, (meth)acryloyloxynaphthalenesulfonic acid, 2-hydroxyethyl acryloyl phosphate, and the like.

[0118] Monomers containing an epoxy group: for example, glycidyl (meth)acrylate, (meth)acrylic acid-2-ethyl glycidyl ether, and the like.

[0119] Monomers containing a cyano group: for example, acrylonitrile, methacrylonitrile, and the like.

[0120] Monomers containing an isocyanate group: for example, 2-isocyanatoethyl (meth)acrylate, and the like.

[0121] Monomers containing an amide group: for example, (meth)acrylamide; N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N,N-dipropyl (meth)acrylamide, N,N-diisopropyl (meth)acrylamide, N,N-di-n-butyl (meth)acrylamide, N,N-di-t-butyl (meth)acrylamide, and the like N,N-dialkyl (meth)acrylamides; N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide, N-n-butyl (meth)acrylamide, and the like N-alkyl (meth)acrylamides; N-vinyl acetamide, and the like N-vinyl carboxylic acid amides; monomers having a hydroxyl group and an amide group, for example, N-(2-hydroxyethyl) (meth)acrylamide, N-(2-hydroxypropyl) (meth)acrylamide, N-(1-hydroxypropyl) (meth)acrylamide, N-(3-hydroxypropyl) (meth)acrylamide, N-(2-hydroxybutyl) (meth)acrylamide, N-(3-hydroxybutyl) (meth)acrylamide, N-(4-hydroxybutyl) (meth)acrylamide, and the like N-hydroxyalkyl (meth)acrylamides; monomers having an alkoxy group and an amide group, for example, N-methoxymethyl (meth)acrylamide, N-methoxyethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, and the like N-alkoxyalkyl (meth)acrylamides; furthermore, N,N-dimethylaminopropyl (meth)acrylamide, N-(meth)acryloylmorpholine, and the like.

[0122] Monomers containing an amino group: for example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate.

[0123] Monomers having an epoxy group: for example, glycidyl (meth)acrylate, methyl glycidyl (meth)acrylate, allyl glycidyl ether.

[0124] Monomers having a nitrogen atom-containing ring: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyl oxazole, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperidine, N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazin-2-one, N-vinyl-3,5-morpholinodione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, N-vinylisothiazole, N-vinylpyridazine, and the like (for example, lactams such as N-vinyl-2-caprolactam and the like).

[0125] Monomers having a succinimide skeleton: for example, N-(meth)acryloyloxymethylidenesuccinimide, N-(meth)acryloyl-6-oxohexamethylenesuccinimide, N-(meth)acryloyl-8-oxohexamethylenesuccinimide, and the like.

[0126] Maleimides: for example, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide, and the like.

[0127] Itaconimides: for example, N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, N-laurylitaconimide, and the like.

[0128] Aminoalkyl (meth) acrylates: for example, aminoethyl (meth) acrylate, N,N-dimethylaminoethyl (meth) acrylate, N,N-diethylaminoethyl (meth) acrylate, t-butylaminoethyl (meth) acrylate.

[0129] Alkoxy-containing monomers: for example, 2-methoxyethyl (meth) acrylate, 3-methoxypropyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, propoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, ethoxypropyl (meth) acrylate, and the like (meth) acryloxyalkyl esters; methoxyethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, methoxypolypropylene glycol (meth) acrylate, and the like alkoxyalkylene glycol (meth) acrylates (for example, alkoxy polyalkylene glycol (meth) acrylates).

[0130] Alkoxysilyl group-containing monomers: for example, 3- (methyl) acryloyloxypropyltrimethoxysilane, 3- (methyl) acryloyloxypropyltriethoxysilane, 3- (methyl) acryloyloxypropylmethyldimethoxysilane, 3- (methyl) acryloyloxypropylmethyldiethoxysilane, (methyl) acrylate esters containing an alkoxysilyl group such as 3- (methyl) acryloyloxypropyltrimethoxysilane, 3- (methyl) acryloyloxypropyltriethoxysilane, 3- (methyl) acryloyloxypropylmethyldimethoxysilane, 3- (methyl) acryloyloxypropylmethyldiethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, and the like.

[0131] Vinyl esters: for example, vinyl acetate, vinyl propionate, and the like.

[0132] Vinyl ethers: for example, methyl vinyl ether, ethyl vinyl ether, and the like vinyl alkyl ethers.

[0133] Aromatic vinyl compounds: for example, styrene, a-methylstyrene, vinyltoluene, and the like.

[0134] Olefins: for example, ethylene, butadiene, isoprene, isobutylene, and the like.

[0135] (meth) Acrylic acid esters having an alicyclic hydrocarbon group: for example, (meth) acrylate esters containing an alicyclic hydrocarbon group such as (meth) acrylate cyclopentyl ester, (meth) acrylate cyclohexyl ester, (meth) acrylate isobornyl ester, (meth) acrylate dicyclopentyl ester, (meth) acrylate adamantyl ester, and the like.

[0136] (meth) Acrylic acid esters having an aromatic hydrocarbon group: for example, (meth) acrylate esters containing an aromatic hydrocarbon group such as (meth) acrylate phenyl ester, (meth) acrylate phenoxyethyl ester, (meth) acrylate benzyl ester, and the like.

[0137] In addition, (meth) acrylate esters containing a heterocycle such as (meth) acrylate tetrahydrofurfuryl ester, (meth) acrylate esters containing a halogen atom such as chlorovinyl group-containing (meth) acrylate esters, fluorine atom-containing (meth) acrylate esters, (meth) acrylate esters containing a silicon atom such as silicone (meth) acrylate esters, (meth) acrylate esters derived from alcohols obtained from terpene compounds, and the like.

[0138] In the case of using such a copolymerizable monomer, the amount thereof is not particularly limited, and it is appropriate to be 0.01% by mass or more of the entire monomer components. From the viewpoint of more favorably exerting the effects of using the copolymerizable monomer, the amount of the copolymerizable monomer can be set to 0.1% by mass or more of the entire monomer components, or can be set to 0.5% by mass or more. In addition, from the viewpoint of easily achieving a balance of adhesive properties, it is appropriate for the amount of the copolymerizable monomer to be 50% by mass or less of the entire monomer components, and it is preferable for the amount to be 40% by mass or less.

[0139] In some embodiments, the monomer component constituting the acrylic polymer (A) can include a monomer having a nitrogen atom. By using a monomer having a nitrogen atom, the cohesive force of the adhesive can be improved, and preferably the peeling strength after photocuring is improved. As one preferred example of the monomer having a nitrogen atom, a monomer having a ring containing a nitrogen atom can be cited. As the monomer having a ring containing a nitrogen atom, the monomers exemplified above or the like can be used, and for example, an N-vinyl cyclic amide represented by general formula (1) can be used.

[0140]

[0141] Here, in general formula (1), R 1 is a divalent organic group, and specifically - (CH2) n -. n is an integer of 2 to 7 (preferably 2, 3, or 4). Among them, N-vinyl-2-pyrrolidone can be preferably used. As another preferred example of the monomer having a nitrogen atom, a (meth) acrylamide can be cited.

[0142] The amount of the monomer having a nitrogen atom (preferably the monomer having a ring containing a nitrogen atom) is not particularly limited, and for example, it can be 1% by weight or more, 3% by weight or more, and further 5% by weight or more, or 7% by weight or more, of the entire monomer component. In some embodiments, the amount of the monomer having a nitrogen atom can be 10% by weight or more, 15% by weight or more, or 20% by weight or more, of the entire monomer component. In addition, it is appropriate that the amount of the monomer having a nitrogen atom is set to be 40% by weight or less, for example, of the entire monomer component, and it can be set to be 35% by weight or less, 30% by weight or less, or 25% by weight or less. In other embodiments, the amount of the monomer having a nitrogen atom can be set to be 20% by weight or less, or 15% by weight or less, of the entire monomer component.

[0143] In some embodiments, the monomer component constituting the acrylic polymer (A) can include a hydroxyl group-containing monomer. By using a hydroxyl group-containing monomer, the cohesive force of the adhesive, the degree of crosslinking (for example, crosslinking based on an isocyanate crosslinking agent) can be appropriately adjusted. The amount used when using a hydroxyl group-containing monomer is not particularly limited, and can be, for example, 0.01% by weight or more, 0.1% by weight or more, 0.5% by weight or more, 1% by weight or more, 5% by weight or more, or 10% by weight or more, of the entire monomer component. In addition, from the viewpoint of suppressing the water absorption of the adhesive layer, in some embodiments, it is appropriate to set the amount of the hydroxyl group-containing monomer to be, for example, 40% by weight or less, 30% by weight or less, 25% by weight or less, or 20% by weight or less, of the entire monomer component. In other embodiments, the amount of the hydroxyl group-containing monomer can be set to be, for example, 15% by weight or less, 10% by weight or less, or 5% by weight or less, of the entire monomer component.

[0144] In some embodiments, the proportion of the carboxyl group-containing monomer in the monomer component of the acrylic polymer (A) can be, for example, 2% by weight or less, 1% by weight or less, or 0.5% by weight or less (for example, less than 0.1% by weight). As the monomer component of the acrylic polymer (A), a carboxyl group-containing monomer can not be substantially used. Here, not substantially using a carboxyl group-containing monomer means that at least a carboxyl group-containing monomer is not intentionally used. An adhesive layer including an acrylic polymer (A) in which the amount of a carboxyl group-containing monomer is limited as described above is preferable from the viewpoint of preventing metal corrosion. An adhesive sheet having the adhesive layer can also be preferably used, for example, in a manner in which the adhesive layer is in contact with an adherend having a metal material.

[0145] In some embodiments, the monomer component constituting the acrylic polymer (A) can include an alicyclic hydrocarbon group-containing (meth)acrylate. Thereby, the cohesive force of the adhesive can be increased, and the peel strength after photocuring can be improved. As the alicyclic hydrocarbon group-containing (meth)acrylate, the above-described examples of substances, etc. can be used, and, for example, cyclohexyl acrylate, isobornyl acrylate can be preferably used. The amount used when using an alicyclic hydrocarbon group-containing (meth)acrylate is not particularly limited, and can be, for example, 1% by weight or more, 3% by weight or more, or 5% by weight or more, of the entire monomer component. In some embodiments, the amount of the alicyclic hydrocarbon group-containing (meth)acrylate can be 10% by weight or more, or 15% by weight or more, of the entire monomer component. It is appropriate to set the upper limit of the amount of the alicyclic hydrocarbon group-containing (meth)acrylate to be about 40% by weight or less, and, for example, can be 30% by weight or less, or 25% by weight or less (for example, 15% by weight or less, further 10% by weight or less), of the entire monomer component.

[0146] The polymerization method when forming (synthesizing) the polymer (A) from the monomer component is not particularly limited, and various polymerization methods known in the art can be appropriately used. For example, solution polymerization, emulsion polymerization, bulk polymerization, and the like can be appropriately used (typically, in the presence of a thermal polymerization initiator). Light polymerization (typically, in the presence of a photopolymerization initiator) performed by irradiation of ultraviolet rays or the like. Radiation polymerization performed by irradiation of β-rays, γ-rays, or the like. Two or more polymerization methods (for example, stepwise) can also be combined and implemented.

[0147] As the solvent for solution polymerization (polymerization solvent), for example, any one solvent or a mixed solvent of two or more selected from the group consisting of aromatic compounds (typically, aromatic hydrocarbons) such as toluene; esters such as ethyl acetate, butyl acetate; aliphatic or alicyclic hydrocarbons such as hexane, cyclohexane; halogenated alkanes such as 1,2-dichloroethane; lower alcohols (for example, monohydric alcohols having 1 to 4 carbon atoms) such as isopropyl alcohol; ethers such as tert-butyl methyl ether; ketones such as methyl ethyl ketone; and the like can be used.

[0148] At the time of polymerization, a known or conventional thermal polymerization initiator, photopolymerization initiator, or the like can be used depending on the polymerization method, polymerization mode, or the like. Such a polymerization initiator can be used alone or in combination with two or more as appropriate.

[0149] As the thermal polymerization initiator, although not particularly limited, for example, azo-based polymerization initiators, peroxide-based initiators, redox-based initiators obtained from a combination of a peroxide and a reducing agent, substituted ethane-based initiators, and the like can be used. More specifically, for example, azo-based initiators such as 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazoline-2-yl)propane] dihydrochloride, 2,2'-azobis(N,N'-dimethyleneisobutylamidine), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate; persulfates such as potassium persulfate, ammonium persulfate; peroxide-based initiators such as benzoyl peroxide, tert-butyl hydroperoxide, hydrogen peroxide; substituted ethane-based initiators such as phenyl-substituted ethane; redox-based initiators such as a combination of a persulfate and sodium bisulfite, a combination of a peroxide and sodium ascorbate; and the like can be exemplified, but are not limited thereto. The thermal polymerization can be preferably performed at a temperature of about 20 to 100°C (typically, 40 to 80°C), but is not limited thereto.

[0150] As the photopolymerization initiator, although not particularly limited, for example, a ketal-based photopolymerization initiator, an acetophenone-based photopolymerization initiator, a benzoin ether-based photopolymerization initiator, an acyloxyphosphine-based photopolymerization initiator, an α-keto alcohol-based photopolymerization initiator, an aromatic sulfonyl chloride-based photopolymerization initiator, a photoactive oxime-based photopolymerization initiator, a benzoin-based photopolymerization initiator, a benzil-based photopolymerization initiator, a benzophenone-based photopolymerization initiator, a thioxanthone-based photopolymerization initiator, or the like can be used.

[0151] The amount of the polymerization initiator can be used in a usual amount corresponding to the polymerization method, the polymerization mode, or the like, and is not particularly limited. For example, about 0.001 to 5 parts by weight (typically, about 0.01 to 2 parts by weight, for example, about 0.01 to 1 part by weight) of the polymerization initiator can be used with respect to 100 parts by weight of the monomer as the polymerization target.

[0152] In the above polymerization, various chain transfer agents (which can also be understood as molecular weight regulators or polymerization degree regulators) known in the art can be used as needed. As the chain transfer agent, mercaptans such as n-dodecyl mercaptan, t-dodecyl mercaptan, mercaptoacetic acid, and α-thioglycerol can be used. Alternatively, a chain transfer agent not containing a sulfur atom (a non-sulfur chain transfer agent) can also be used. As specific examples of the non-sulfur chain transfer agent, anilines such as N,N-dimethylaniline and N,N-diethylaniline; terpenes such as α-pinene and terpinolene; styrenes such as α-methylstyrene and α-methylstyrene dimer; compounds having a benzylidene group such as dibenzylideneacetone, cinnamic alcohol, and cinnamaldehyde; hydroquinones such as p-benzoquinone and naphthoquinone; quinones such as benzoquinone and naphthoquinone; olefins such as 2,3-dimethyl-2-butene and 1,5-cyclooctadiene; alcohols such as phenol, benzyl alcohol, and allyl alcohol; and benzyl hydrides such as diphenylbenzene and triphenylbenzene can be listed. The chain transfer agent can be used alone or in combination of two or more. Note that the technology disclosed herein can also be preferably implemented without using a chain transfer agent.

[0153] The amount of the chain transfer agent used when the chain transfer agent is used can be set to about 0.005 parts by weight to about 1 part by weight, for example, with respect to 100 parts by weight of the monomer component. In some modes, from the viewpoint of impact resistance, the amount of the chain transfer agent with respect to 100 parts by weight of the monomer component can be set to 0.01 parts by weight or more, can be set to 0.03 parts by weight or more, can be set to 0.05 parts by weight or more, or can be set to 0.07 parts by weight or more. In addition, in some modes, from the viewpoint of deformation resistance, the amount of the chain transfer agent with respect to 100 parts by weight of the monomer component can be 0.5 parts by weight or less, can be 0.2 parts by weight or less, can be 0.1 parts by weight or less, or can be less than 0.1 parts by weight (for example, 0.09 parts by weight or less).

[0154] The glass transition temperature (Tg) of the polymer (A) is not particularly limited in the technology disclosed herein, and is preferably less than 0°C, more preferably less than -10°C, and even more preferably less than -20°C. By lowering the Tg of the polymer (A), there is a tendency for the impact resistance described above to be improved. In some embodiments, the Tg of the polymer (A) can be less than -25°C, and can also be less than -30°C. In addition, the Tg of the polymer (A) is typically -80°C or greater, and for example, can be -70°C or greater, can also be -60°C or greater, and can also be -55°C or greater. From the viewpoint of improving the elastic modulus described above, in some embodiments, the Tg of the polymer (A) is preferably -50°C or greater, more preferably -45°C or greater, can be -40°C or greater, can also be -38°C or greater, and can also be -35°C or greater.

[0155] Herein, the Tg of a polymer in the present specification refers to the Tg calculated using the Fox equation based on the composition of monomer components used in the preparation of the polymer. The Fox equation described above is a relationship between the Tg of a copolymer and the glass transition temperatures Tgi of homopolymers of the monomers that make up the copolymer.

[0156] 1 / Tg = ∑(Wi / Tgi)

[0157] In the Fox equation described above, Tg represents the glass transition temperature of the copolymer (unit: K), Wi represents the weight fraction of monomer i in the copolymer (copolymerization ratio on a weight basis), and Tgi represents the glass transition temperature of the homopolymer of monomer i (unit: K). In the case where the polymer for which the Tg is to be determined is a homopolymer, the Tg of the homopolymer coincides with the Tg of the polymer that is the object.

[0158] The glass transition temperatures of the homopolymers used in the calculation of the Tg were adopted from values described in publicly known documents. For example, for the monomers listed below, the following values were used as the glass transition temperatures of the homopolymers of the monomers.

[0159] n-butyl acrylate - 55°C

[0160] 2-ethylhexyl acrylate - 70°C

[0161] isostearyl acrylate - 18°C

[0162] cyclohexyl acrylate 15°C

[0163] N-vinyl-2-pyrrolidone 54°C

[0164] 2-hydroxyethyl acrylate - 15°C

[0165] 4-hydroxybutyl acrylate - 40°C

[0166] For the glass transition temperature of the homopolymer of the monomer other than the above examples, the value described in "Polymer Handbook" (3rd edition, John Wiley & Sons, Inc., 1989) is adopted. In the case where a plurality of values are described in the document, the highest value is adopted.

[0167] The weight average molecular weight (Mw) of the polymer (A) is not particularly limited. From the viewpoint of more balancedly having a deformation resistance and an impact resistance, the Mw of the polymer (A) is, for example, about 10 x 10 4 The above is appropriate, and preferably exceeds 20 x 10 4 , can exceed 30 x 10 4 , can exceed 40 x 10 4 , can exceed 50 x 10 4 . In addition, the upper limit of the Mw of the polymer (A) can be about 500 x 10 4 or less. From the viewpoint of the adhesion to an adherend, a peeling strength, the Mw of the polymer (A) is, for example, 300 x 10 4 or less, can be 150 x 10 4 or less, can be 100 x 10 4 or less, can be 90 x 10 4 or less, can be 75 x 10 4 or less.

[0168] The above examples of the Mw can be applied to the Mw of the polymer (A) in the adhesive layer of the adhesive sheet disclosed herein, and can be applied to the Mw of the polymer (A) in the adhesive composition used for forming the adhesive layer.

[0169] Note that the Mw refers to a value converted to a standard polystyrene by gel permeation chromatography (GPC). As the GPC device, for example, a device of a trade name "HLC-8220 GPC" (manufactured by Tosoh Corporation) or the like can be used. As the measurement conditions of the GPC, for example, the following method can be adopted. The Mw in the Examples described later is measured by the following method.

[0170] (GPC measurement conditions)

[0171] Device: HLC-8220 GPC, manufactured by Tosoh Corporation

[0172] Column:

[0173] Sample column: TSKguard column Super HZ-H (1) + TSKgel Super HZM-H (2), manufactured by Tosoh Corporation

[0174] Reference column; TSKgel Super H-RC (1) manufactured by Tosoh Corporation

[0175] Flow rate: 0.6 mL / min

[0176] Injection amount: 10 μL

[0177] Column temperature: 40°C

[0178] Eluent: THF

[0179] Injection sample concentration: 0.2% by weight

[0180] Detector: differential refractometer

[0181] The weight average molecular weight was calculated by conversion to polystyrene.

[0182] (Photo-reactive monomer (B))

[0183] In several preferred modes, the adhesive layer can contain a photo-reactive monomer (B) in addition to the polymer (A) (e.g., the acrylic polymer (A)) described above. As the photo-reactive monomer (B), a compound having a number of ethylenically unsaturated groups (hereinafter also referred to as "the number of functional groups") of 2 or more contained within the molecule can be used. The upper limit of the number of functional groups of the compound used as the photo-reactive monomer (B) is not particularly limited. The number of functional groups can be, for example, 50 or less, 40 or less, 30 or less, 20 or less, or 15 or less. In several modes, a compound having an ethylenically unsaturated group with a number of functional groups of, for example, 2 to 10 can be used, preferably a compound with a number of functional groups of 2 to 8, and more preferably a compound with a number of functional groups of 2 to 6. The photo-reactive monomer (B) can be used alone or in combination with two or more.

[0184] The photo-reactive monomer (B) contained in the adhesive layer can form a crosslinked structure by causing the ethylenically unsaturated group to react by light (e.g., ultraviolet light) irradiation or the like after being attached to the adherend. The adhesive sheet containing the photo-reactive monomer (B) in the adhesive layer is cured by ultraviolet light irradiation or the like after being attached to the adherend, thereby improving the deformation resistance of the adhesive layer. Thus, good followability to the surface shape of the adherend when attached to the adherend and high deformation resistance after attachment can be suitably combined.

[0185] Examples of the above-mentioned ethylenically unsaturated group include acryloyl group, methacryloyl group, vinyl group, and allyl group, but are not limited thereto. The two or more ethylenically unsaturated groups possessed by the photoreactive monomer (B) in the molecule can be the same groups as each other, or can be two or more different groups. As the ethylenically unsaturated group preferred from the viewpoint of photoreactivity, acryloyl group and methacryloyl group can be mentioned. Of these, acryloyl group is preferred.

[0186] The functional group equivalent of the compound used as the photoreactive monomer (B) is not particularly limited. The above-mentioned functional group equivalent can be, for example, about 50 to 10,000 g / mol, about 50 to 8,000 g / mol, about 50 to 5,000 g / mol, about 50 to 3,000 g / mol, about 50 to 2,000 g / mol. In some aspects, as the photoreactive monomer (B), from the viewpoint of photocurability, a compound having a functional group equivalent of about 60 to 800 g / mol (more preferably about 80 to 600 g / mol) can be preferably used.

[0187] Note that the functional group equivalent of the photoreactive monomer (B) is calculated by dividing the molecular weight [g / mol] of the photoreactive monomer (B) by the number of ethylenically unsaturated functional groups possessed by the photoreactive monomer (B). The molecular weight of the photoreactive monomer (B) can be obtained, for example, by the GPC method, in the form of weight average molecular weight converted to standard polystyrene. In addition, as the molecular weight [g / mol] of the photoreactive monomer (B), the manufacturer's nominal value or the molecular weight calculated from the molecular structure can be used.

[0188] The molecular weight of the photoreactive monomer (B) is not particularly limited, and can be selected in a manner suitable for exerting a desired effect. For example, as the photoreactive monomer (B), a monomer having a molecular weight of about 20,000 or less can be used. From the viewpoint of ease of preparation of the adhesive composition, coatability, and the like, in some aspects, the molecular weight of the photoreactive monomer (B) can be, for example, 16,000 or less, 10,000 or less, 4,000 or less, 1,500 or less, 1,000 or less. The molecular weight of the photoreactive monomer (B) is, for example, 100 or more, and is typically 120 or more. From the viewpoint of processability, handleability, and the like of the adhesive sheet, in some aspects, the molecular weight of the photoreactive monomer (B) can be, for example, 150 or more, 200 or more, 280 or more, 350 or more, 420 or more, 480 or more, 550 or more.

[0189] The amount of the photoreactive monomer (B) contained in the adhesive layer of the adhesive sheet disclosed herein is not particularly limited and can be appropriately set in accordance with the target properties (e.g., the modulus of elasticity of the adhesive layer after photocuring). Among the several ways in which the adhesive layer contains the polymer (A) and the photoreactive monomer (B), it is appropriate, for example, for the amount of the photoreactive monomer (B) to be 1 part by weight or more, 3 parts by weight or more, with respect to 100 parts by weight of the polymer (A) contained in the adhesive layer. From the viewpoint of easily increasing the modulus of elasticity of the adhesive layer after photocuring, the amount of the photoreactive monomer (B) can be 5 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, or 20 parts by weight or more, with respect to 100 parts by weight of the polymer (A). In addition, from the viewpoint of the cohesion of the adhesive layer before photocuring, the processability (e.g., machinability) of the adhesive sheet, it is appropriate for the amount of the photoreactive monomer (B) to be 80 parts by weight or less, preferably 60 parts by weight or less, 50 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, with respect to 100 parts by weight of the polymer (A).

[0190] In several ways, the above-mentioned adhesive layer preferably contains at least a compound B1 having a ring structure and two or more olefinic unsaturated groups in a molecule as the above-mentioned photoreactive monomer (B). When using an adhesive layer containing the compound B1 having such a structure, the deformation resistance of the adhesive layer can be effectively improved by light irradiation. The ring in the above-mentioned ring structure can be an aliphatic ring or an aromatic ring. In addition, the above-mentioned ring can be a carbocyclic ring or a heterocyclic ring. The number of rings contained in one molecule of the compound B1 can be one or two or more. The upper limit of the number of rings contained in the compound B1 is not particularly limited and can be, for example, 100 or less, 70 or less, 50 or less, 30 or less, 15 or less, 8 or less, 6 or less, 5 or less, or 4 or less. In the case where the compound B1 contains two or more rings, these rings can form a fused ring formed by two or more rings (typically, a fused ring of a bicyclic or tricyclic ring) or can not form a fused ring. The above-mentioned ring is preferably contained in the main chain of the compound B1. That is, it is preferable that one of the olefinic unsaturated groups possessed by the compound B1 is connected to the other at least one olefinic unsaturated group by means of the above-mentioned ring structure. The compound B1 can be used alone or in combination with two or more kinds.

[0191] As the compound B1, a compound having a ring structure and two or more ethylenic unsaturated groups in the molecule and having a functional group equivalent of 100 g / mol or more can be preferably used. When an adhesive sheet containing the compound B1 satisfying the above-mentioned functional group equivalent is used in the adhesive layer, the resistance to deformation is high and the joining with high impact resistance can be suitably formed. As a reason for obtaining such an effect, although not particularly limited in explanation, it can be considered that, when the compound B1 is used, the elastic modulus of the adhesive layer after light irradiation can be effectively increased by the rigidity of the ring structure, the resistance to deformation is imparted, on the other hand, by the functional group equivalent of the compound B1 being the prescribed value or more, the distance between the crosslinking points can be maintained, and the crosslinking structure with high resistance to impact can be formed. In some modes, the functional group equivalent of the compound B1 can be, for example, 120 g / mol or more, 150 g / mol or more, 180 g / mol or more, 230 g / mol or more, 280 g / mol or more, 320 g / mol or more, or 350 g / mol or more. By increasing the functional group equivalent of the compound B1, there is a tendency that the impact resistance is increased. In addition, the functional group equivalent of the compound B1 can be, for example, 10,000 g / mol or less, 8,000 g / mol or less, 5,000 g / mol or less, 3,000 g / mol or less, or 2,000 g / mol or less. In some modes, the functional group equivalent of the compound B1 is preferably 800 g / mol or less, more preferably 600 g / mol or less, from the viewpoint of photocurability and the like. In some modes, the functional group equivalent of the compound B1 can be 500 g / mol or less, 400 g / mol or less, or 300 g / mol or less.

[0192] In some modes, the number of functional groups of the compound B1 can be, for example, 2 to 50, 2 to 40, 2 to 30, 2 to 10, for example, preferably 2 to 6, 2 to 4, or 2 to 3. In some modes, a compound B1 having a number of functional groups of 2 can be preferably used.

[0193] The compound B1 can also have a functional group other than the ethylenic unsaturated group. As examples of the functional group other than the ethylenic unsaturated group, a hydroxyl group, a carboxyl group, an amino group, and the like can be listed. As preferred examples of the functional group other than the ethylenic unsaturated group, a hydroxyl group and an amino group can be listed.

[0194] As examples of the compound B1, there can be mentioned a bisphenol A glycidyl ether (meth)acrylic adduct, a bisphenol A glycidyl amine (meth)acrylic adduct, a bisphenol A glycidyl ester (meth)acrylic adduct, and the like of a bisphenol A type epoxy (meth)acrylate; an oxirane (EO) modified bisphenol A di(meth)acrylate, a propylene oxide (PO) modified bisphenol A di(meth)acrylate, and the like of an alkylene oxide modified bisphenol A (meth)acrylate; a bisphenol F glycidyl ether (meth)acrylic adduct, a bisphenol F glycidyl amine (meth)acrylic adduct, a bisphenol F glycidyl ester (meth)acrylic adduct, and the like of a bisphenol F type epoxy (meth)acrylate; an EO modified bisphenol F di(meth)acrylate, a PO modified bisphenol F di(meth)acrylate, and the like of an alkylene oxide modified bisphenol F (meth)acrylate; a bisphenol E glycidyl ether (meth)acrylic adduct, a bisphenol E glycidyl amine (meth)acrylic adduct, a bisphenol E glycidyl ester (meth)acrylic adduct, and the like of a bisphenol E type epoxy (meth)acrylate; an EO modified bisphenol E di(meth)acrylate, a PO modified bisphenol E di(meth)acrylate, and the like of an alkylene oxide modified bisphenol E (meth)acrylate; a 9,9-bis(4-hydroxyphenyl)fluorene di(meth)acrylate, a 9,9-bis[4-(2-hydroxyethoxy)phenyl]fluorene di(meth)acrylate, and the like of a (meth)acrylate containing a fluorene skeleton; a tricyclodecane dimethanol di(meth)acrylate, a hydrogenated bisphenol A type epoxy (meth)acrylate, a hydrogenated bisphenol F type epoxy (meth)acrylate, a hydrogenated bisphenol E type epoxy (meth)acrylate, a hydrogenated phthalic acid type epoxy (meth)acrylate, a hydrogenated terpene phenol (meth)acrylate, a 1,4-cyclohexane dimethanol diglycidyl ether (meth)acrylate, and the like of a (meth)acrylate having an aliphatic ring (which can be an alicyclic condensed ring); a (meth)acrylic adduct of a novolak type epoxy resin; a (meth)acrylic adduct of a sulfide type epoxy resin; a (meth)acrylic adduct of a naphthalene type epoxy resin; a (meth)acrylic adduct of a dicyclopentadiene type epoxy resin; a (meth)acrylic adduct of an alkyl diphenol type epoxy resin; a (meth)acrylic adduct of a biphenyl type epoxy resin; a (meth)acrylic adduct of a terpene phenol resin; a tri(2-hydroxyethyl)isocyanurate di(meth)acrylate, a tri(2-hydroxyethyl)isocyanurate tri(meth)acrylate, and the like of an isocyanurate type (meth)acrylate; divinylbenzene; a p-benzenediol di(meth)acrylate; a m-benzenediol di(meth)acrylate; a modified product (for example, an amine modified product, an acid modified product, a halogen modified product) of any of the above materials, and the like, but are not limited thereto. Of these, a compound B1 having an aromatic carbon ring can be preferably used. As a preferable example of the compound B1, there can be mentioned a bisphenol A type epoxy (meth)acrylate, an alkylene oxide modified bisphenol A (meth)acrylate, a modified product (for example, an amine modified product) thereof, and the like of a compound containing a bisphenol A structure.

[0195] As commercially available products which can be used as the compound B1, there can be mentioned "A-DCP", "A-BPE-4" manufactured by Shin-Nakamura Chemical Industrial Co., Ltd., "Viscoat #540", "Viscoat #700HV" manufactured by Osaka Organic Chemical Industry Ltd., "R-114F" manufactured by Japan Epoxy Resin Co., Ltd., "Epoxy Ester 3000A", "Epoxy Ester 80MFA" manufactured by Kyoeisha Chemical Co., Ltd., "EBECRYL 3700", "EBECRYL 3703", "EBECRYL 3603" manufactured by DAICEL-ALLNEX LTD., and the like, but are not limited thereto.

[0196] The amount of the compound B1 with respect to 100 parts by weight of the polymer (A) contained in the adhesive layer is not particularly limited, and can be set to 0.5 parts by weight or more, for example. From the viewpoint of easily obtaining an adhesive layer which balances the resistance to deformation and the resistance to impact, in some modes, the amount of the compound B1 with respect to 100 parts by weight of the polymer (A) can be 1 part by weight or more, 3 parts by weight or more, 5 parts by weight or more, 7 parts by weight or more, 10 parts by weight or more, 15 parts by weight or more, for example. In addition, from the viewpoint of the cohesiveness of the adhesive layer before photocuring and the handleability of the bonded sheet, it is appropriate that the amount of the compound B1 with respect to 100 parts by weight of the polymer (A) is set to 80 parts by weight or less, preferably 60 parts by weight or less, can be 50 parts by weight or less, 40 parts by weight or less, 35 parts by weight or less, 25 parts by weight or less, 15 parts by weight or less.

[0197] In some modes, in the above adhesive layer, as the above light-reactive monomer (B), a compound B2 having a number of functional groups of 2 or more and not having a ring structure in the molecule can be contained. The compound B2 is preferably used in combination with the compound B1. Thereby, the crosslinking structure of the adhesive layer is adjusted, and a joint which more suitably balances the resistance to deformation and the resistance to impact can be formed. The compound B2 can be used alone or in combination with two or more kinds.

[0198] The number of functional groups of the compound B2 can be 50 or less, 40 or less, 30 or less, 20 or less, 15 or less, for example. In some modes, the number of functional groups of the compound B2 used can be 2 to 10, preferably 3 to 10, 3 to 8, 4 to 6, for example. For example, in a mode in which a compound having a number of functional groups of 2 is used as the compound B1, it becomes advantageous to use a compound B2 having a number of functional groups of 3 or more (preferably 4 or more, more preferably 5 or more, further preferably 6 or more).

[0199] The functional group equivalent weight of the compound B2 is not particularly limited, and can be, for example, 5,000 g / mol or less, 2,000 g / mol or less, or 1,000 g / mol or less. In some aspects, the functional group equivalent weight of the compound B2 can be, for example, 600 g / mol or less, 400 g / mol or less, 300 g / mol or less, 200 g / mol or less, 150 g / mol or less, 100 g / mol or less, from the viewpoints of photocurability, hardness improvement of the cured product, and the like. The functional group equivalent weight of the compound B2 is typically 50 g / mol or more, preferably 60 g / mol or more, and can be 70 g / mol or more, 80 g / mol or more, or 90 g / mol or more.

[0200] Examples of the compound that can be used as the compound B2 include pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, trimethyloloethane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, neopentyl glycol di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, an EO-modified product and / or a PO-modified product of any of the above, and the like, but are not limited thereto.

[0201] The amount of the compound B2 used with respect to 100 parts by weight of the polymer (A) contained in the adhesive layer is not particularly limited, and can be, for example, 0.1 parts by weight or more. From the viewpoint of easily obtaining an adhesive layer that balances the deformation resistance and the impact resistance, in some aspects, the amount of the compound B2 with respect to 100 parts by weight of the polymer (A) can be, for example, 1 part by weight or more, 2 parts by weight or more, 4 parts by weight or more, 6 parts by weight or more, 10 parts by weight or more, or 12 parts by weight or more. From the viewpoint of suppressing a decrease in adhesion to the adherend due to excessive crosslinking, in some aspects, the amount of the compound B2 with respect to 100 parts by weight of the polymer (A) is appropriately set to be 25 parts by weight or less, preferably 17 parts by weight or less, 15 parts by weight or less, 13 parts by weight or less, or 9 parts by weight or less.

[0202] In the case of using the compound B1 in combination with the compound B2, as the compound B2, a compound having a functional group number of 3 or more and having a functional group equivalent smaller than the functional group equivalent of the compound B1 with which it is combined can be preferably used. In some cases, the ratio of the functional group equivalent FE2 of the compound B2 to the functional group equivalent FE1 of the compound B1 (FE2 / FE1) can be, for example, 0.9 or less, 0.7 or less, 0.5 or less, or 0.4 or less. In the case of using the compound B2 in this way, the effect of increasing the elastic modulus brought about by the photoreactive monomer (B) can be efficiently exhibited. The lower limit of the ratio (FE2 / FE1) is not particularly limited, and can be, for example, 0.01 or more, 0.1 or more, or 0.2 or more.

[0203] In the case of using the compound B1 in combination with the compound B2, the weight ratio of the amount W2 of the compound B2 to the amount W1 of the compound B1 (W2 / W1) is not particularly limited. In some cases, the weight ratio (W2 / W1) can be, for example, 0.05 to 10, 0.1 to 5, 0.2 to 3, or 0.3 to 2. By setting the weight ratio (W2 / W1) within any of the above ranges, there is a tendency to favorably exhibit the effect of using the compound B1 in combination with the compound B2.

[0204] In other cases where the photoreactive monomer (B) (typically, the compound B2) is used, the amount of the photoreactive monomer (B) (typically, the compound B2) used can be set to be about 3% by weight or less, preferably about 2% by weight or less, and more preferably about 1% by weight or less (for example, about 0.5% by weight or less) of the monomer component of the above-described polymer (A). The lower limit of the amount used when the photoreactive monomer (B) (typically, the compound B2) is used is not particularly limited as long as it is greater than 0% by weight. It is appropriate to set the amount of the photoreactive monomer (B) (typically, the compound B2) to be about 0.001% by weight or more (for example, about 0.01% by weight or more) of the monomer component.

[0205] In some cases, the photoreactive monomer (B) can be contained in the adhesive layer in a free form. The adhesive layer can be favorably formed using an adhesive composition that contains the photoreactive monomer (B) in a free form. The "free form" here means that the photoreactive monomer (B) is not chemically bonded to other components (for example, the polymer (A)) contained in the adhesive layer or the adhesive composition. The adhesive composition that contains the photoreactive monomer (B) in a free form is advantageous in terms of ease of preparation and inhibition of gelation.

[0206] In other embodiments, at least a portion of the photoreactive monomer (B) can be included in the adhesive layer in a form chemically bonded to other components (e.g., the polymer (A), a crosslinking agent described later, etc.) contained in the adhesive layer or the adhesive composition, from the viewpoint of improving the processability of the adhesive sheet, etc. The above chemical bonding can be, for example, a bond formed by reaction between a functional group F1 other than the ethylenically unsaturated group possessed by the photoreactive monomer (B) within the molecule and a functional group F2 that can react with the functional group F1 possessed by the above other component within the molecule. The above other component can be a crosslinking agent by which the photoreactive monomer (B) is bonded to the polymer (A).

[0207] (acrylic oligomer)

[0208] The adhesive layer of the adhesive sheet disclosed herein can contain an acrylic oligomer from the viewpoint of improving the cohesive force, improving the adhesion to a surface (e.g., a surface of a support substrate in the adhesive sheet, a surface of an adherend to which the adhesive sheet is attached, etc.) adjacent to the adhesive layer, etc. The adhesive layer containing the acrylic oligomer can be preferably formed using an adhesive composition containing the acrylic oligomer. As the acrylic oligomer, a substance having a higher Tg than the Tg of the above polymer (A) is preferably used.

[0209] The Tg of the above acrylic oligomer is not particularly limited and can be, for example, about 20°C or higher and 300°C or lower. The Tg can be, for example, about 30°C or higher, about 40°C or higher, about 60°C or higher, about 80°C or higher, or about 100°C or higher. When the Tg of the acrylic oligomer is high, there is a tendency that the effect of improving the cohesive force generally becomes high. In addition, from the viewpoint of the anchoring property to the support substrate, the impact absorption property, etc., the Tg of the acrylic oligomer can be, for example, about 250°C or lower, about 200°C or lower, about 180°C or lower, or about 150°C or lower. Note that the Tg of the acrylic oligomer is also a value calculated based on the Fox formula, like the Tg of the polymer (A).

[0210] The Mw of the acrylic oligomer is not particularly limited, and for example, it is appropriate for it to be 1,000 or more, 1,500 or more, 2,000 or more, or 3,000 or more. In addition, for example, it is appropriate for the Mw of the acrylic oligomer to be 30,000 or less, 10,000 or less, 7,000 or less, or 5,000 or less. When the Mw is within the above range, it is easy to appropriately exert the effect of improving the cohesion of the adhesive layer and the adhesion to the adjacent surface. The Mw of the acrylic oligomer can be measured by GPC, and is obtained as a value converted to standard polystyrene. Specifically, for example, it can be measured in an HPLC 8020 manufactured by Tosoh Corporation, using TSKgel GMH-H (20) x 2 as the column, and tetrahydrofuran solvent at a flow rate of about 0.5 mL / min.

[0211] As the monomer component constituting the acrylic oligomer, various (meth)acrylic acid C 1-20 alkyl esters; various (meth)acrylic acid esters containing an alicyclic hydrocarbon group; various (meth)acrylic acid esters containing an aromatic hydrocarbon group; (meth)acrylic acid esters derived from alcohols obtained from terpene compounds; and the like (meth)acrylic acid ester monomers. These can be used alone or in combination with two or more.

[0212] From the viewpoint of improving adhesion, it is preferable that the acrylic oligomer contain, as a monomer unit, an acrylic monomer having a bulky structure, represented by (meth)acrylic acid alkyl esters having a branched structure such as (meth)acrylic acid isobutyl ester and (meth)acrylic acid tert-butyl ester, (meth)acrylic acid esters containing an alicyclic hydrocarbon group, and (meth)acrylic acid esters containing an aromatic hydrocarbon group. In addition, in the case where ultraviolet rays are used in the synthesis of the acrylic oligomer or in the production of the adhesive layer, from the aspect that polymerization inhibition is less likely to occur, it is preferable to use a monomer having a saturated hydrocarbon group at the ester terminal, and for example, (meth)acrylic acid alkyl esters having a branched structure and (meth)acrylic acid esters containing a saturated alicyclic hydrocarbon group can be appropriately used.

[0213] The proportion of the (meth)acrylic acid ester monomer in the total monomer component constituting the acrylic oligomer is preferably more than 50% by weight, more preferably 60% by weight or more, and even more preferably 70% by weight or more (for example, 80% by weight or more, and further, 90% by weight or more). In some preferable modes, the acrylic oligomer has a monomer composition consisting essentially of one or two or more (meth)acrylic acid ester monomers. In the case where the monomer component contains (meth)acrylic acid esters containing an alicyclic hydrocarbon group and (meth)acrylic acid C 1-20 In the case where the monomer component contains (meth)acrylic acid alkyl esters, their weight ratio is not particularly limited. In some modes, the (meth)acrylic acid ester containing an alicyclic hydrocarbon group / (meth)acrylic acid C 1-20The weight ratio of the alkyl ester may be set to 10 / 90 or more, 20 / 80 or more, or 30 / 70 or more, for example, and may be set to 90 / 10 or less, 80 / 20 or less, or 70 / 30 or less, for example.

[0214] As the monomer component constituting the acrylic oligomer, a functional group-containing monomer can be used in addition to the above-described (meth)acrylate monomer, as needed. As the functional group-containing monomer, monomers having a nitrogen atom-containing heterocycle such as N-vinyl-2-pyrrolidone, N-acryloylmorpholine, amino group-containing monomers such as N,N-dimethylaminoethyl (meth)acrylate, amide group-containing monomers such as N,N-diethyl (meth)acrylamide, carboxyl group-containing monomers such as AA, MAA, and hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate can be listed. These functional group-containing monomers can be used alone or in combination of two or more. In the case where a functional group-containing monomer is used, the proportion of the functional group-containing monomer in the total monomer component constituting the acrylic oligomer may be 1% by weight or more, 2% by weight or more, or 3% by weight or more, for example, and may be 15% by weight or less, 10% by weight or less, or 7% by weight or less, for example. The acrylic oligomer can also be free of a functional group-containing monomer.

[0215] As the suitable acrylic oligomer, for example, homopolymers of dicyclopentyl methacrylate (DCPMA), cyclohexyl methacrylate (CHMA), isobornyl methacrylate (IBXMA), isobornyl acrylate (IBXA), dicyclopentyl acrylate (DCPA), 1-adamantyl methacrylate (ADMA), 1-adamantyl acrylate (ADA), and copolymers of DCPMA and MMA, DCPMA and IBXMA, ADA and methyl methacrylate (MMA), CHMA and isobutyl methacrylate (IBMA), CHMA and IBXMA, CHMA and acryloylmorpholine (ACMO), CHMA and diethyl acrylamide (DEAA), CHMA and AA can be listed.

[0216] The acrylic oligomer can be formed by polymerizing the monomer component constituting the same. The polymerization method and the polymerization mode are not particularly limited, and various polymerization methods known in the art (for example, solution polymerization, emulsion polymerization, bulk polymerization, photopolymerization, radiation polymerization, and the like) can be employed in a suitable manner. The kind of the polymerization initiator (for example, azo-based polymerization initiator) that can be used as needed is basically as exemplified with respect to the synthesis of the acrylic polymer (A), and the amount of the polymerization initiator and the amount of the chain transfer agent (for example, mercaptans) that is optionally used are appropriately set in a manner to become a desired molecular weight according to technical common sense, and thus a detailed description is omitted.

[0217] In the case where the acrylic oligomer is contained in the adhesive layer or the adhesive composition, the content thereof can be set to, for example, 0.01 parts by weight or more, 0.05 parts by weight or more, 0.1 parts by weight or more, or 0.2 parts by weight or more, relative to 100 parts by weight of the polymer (A), from the viewpoint of obtaining a higher effect. In addition, from the viewpoint of compatibility with the polymer (A) and the like, the content of the acrylic oligomer relative to 100 parts by weight of the polymer (A) is preferably 50 parts by weight or less, more preferably 30 parts by weight or less, and even more preferably 25 parts by weight or less, for example, 10 parts by weight or less, 5 parts by weight or less, or 1 part by weight or less. The adhesive layer or the adhesive composition can also be one that does not contain the acrylic oligomer.

[0218] (Crosslinking agent)

[0219] A crosslinking agent can be used as needed in the adhesive layer. In the adhesive sheet disclosed herein, the crosslinking agent is typically contained in the adhesive layer in a state after crosslinking reaction. By using the crosslinking agent, the cohesive force and the like of the adhesive layer can be appropriately adjusted. In addition, in the adhesive sheet in which the light-reactive monomer (B) is contained in the adhesive layer, for example, by using the crosslinking agent in combination with the light-reactive monomer (B), the softness of the adhesive layer before photocuring and the deformation resistance of the adhesive layer after photocuring of the light-reactive monomer described above can be appropriately combined.

[0220] The type of the crosslinking agent is not particularly limited, and for example, it can be selected from among publicly known crosslinking agents in a manner that the crosslinking agent exerts an appropriate crosslinking function in the adhesive layer, depending on the composition of the adhesive composition. As the crosslinking agent that can be used, isocyanate-based crosslinking agents, epoxy-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, carbodiimide-based crosslinking agents, melamine-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, hydrazine-based crosslinking agents, amine-based crosslinking agents, and the like can be exemplified. They can be used alone or in combination with two or more.

[0221] As the isocyanate-based crosslinking agent, a polyfunctional isocyanate compound having 2 or more functions can be used. For example, aromatic isocyanates such as toluene diisocyanate, xylene diisocyanate, polymethylene polyphenyl diisocyanate, tris(p-isocyanatophenyl) thiophosphate, and diphenylmethane diisocyanate; alicyclic isocyanates such as isophorone diisocyanate; aliphatic isocyanates such as hexamethylene diisocyanate; and the like can be exemplified. As commercially available products, trimethylolpropane / toluene diisocyanate adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate L"), trimethylolpropane / hexamethylene diisocyanate adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HL"), isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "Coronate HX"), trimethylolpropane / xylylene diisocyanate adduct (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-110N"), and the like can be exemplified.

[0222] As the epoxy-based crosslinking agent, a substance having 2 or more epoxy groups in one molecule can be used without particular limitation. An epoxy-based crosslinking agent having 3 to 5 epoxy groups in one molecule is preferred. As specific examples of the epoxy-based crosslinking agent, N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, and the like can be exemplified. As commercially available products of the epoxy-based crosslinking agent, "TETRAD-X" and "TETRAD-C" manufactured by Mitsubishi Gas Chemical Company, Inc., "Epichlone CR-5L" manufactured by DIC Corporation, "DENACOL EX-512" manufactured by Nagase Chemtex Corporation, and "TEPIC-G" manufactured by Nissan Chemical Industries, Ltd., and the like can be exemplified.

[0223] As the oxazoline-based crosslinking agent, a substance having 1 or more oxazoline groups in one molecule can be used without particular limitation.

[0224] As examples of the aziridine-based crosslinking agent, trimethylolpropane tris[3-(1-aziridinyl)propionate], trimethylolpropane tris[3-(1-(2-methyl)aziridinylpropionate)], and the like can be exemplified.

[0225] As the carbodiimide-based crosslinking agent, a low-molecular compound or a high-molecular compound having 2 or more carbodiimide groups can be used.

[0226] In several modes, peroxides can also be used as the crosslinking agent. As the peroxide, mention can be made of di(2-ethylhexyl) peroxydicarbonate, di(4-tert-butylcyclohexyl) peroxydicarbonate, di-sec-butyl peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-hexyl peroxyneopentanoate, tert-butyl peroxyneopentanoate, dilauryl peroxydicarbonate, di-n-octyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl isobutyrate peroxydicarbonate, dibenzoyl peroxide, and the like. As the peroxide in which the crosslinking reaction efficiency is particularly excellent, mention can be made of di(4-tert-butylcyclohexyl) peroxydicarbonate, dilauryl peroxydicarbonate, dibenzoyl peroxide, and the like. Note that in the case where a peroxide is used as the above-mentioned polymerization initiator, the peroxide that is not used in the polymerization reaction and remains can also be used in the crosslinking reaction. At this time, the residual amount of the peroxide is quantified, and in the case where the proportion of the peroxide does not satisfy the prescribed amount, the peroxide is added as necessary in such a manner as to become the prescribed amount. The quantification of the peroxide can be performed by the method described in Japanese Patent No. 4971517.

[0227] The amount of use of the crosslinking agent (the total amount of use in the case where two or more crosslinking agents are used) is not particularly limited. From the viewpoint of achieving an adhesive that exhibits adhesion properties such as adhesion force, cohesion, and the like in a balanced manner, it is appropriate that the amount of use of the crosslinking agent be 5 parts by weight or less, can be 3 parts by weight or less, can be 2 parts by weight or less, can be 1 part by weight or less, or can be less than 1 part by weight, with respect to 100 parts by weight of the polymer (A). In the mode in which the crosslinking agent is used in combination with the photoreactive monomer (B), from the viewpoint of easily and appropriately exerting the effects brought about by the combination use, the amount of use of the crosslinking agent can be, for example, 0.80 parts by weight or less, can be 0.60 parts by weight or less, can be 0.30 parts by weight or less, or can be 0.10 parts by weight or less, with respect to 100 parts by weight of the polymer (A). The lower limit of the amount of use of the crosslinking agent is not particularly limited, and the crosslinking agent can be used in an amount of more than 0 parts by weight with respect to 100 parts by weight of the polymer (A). In several modes, the amount of use of the crosslinking agent can be, for example, 0.001 parts by weight or more, can be 0.01 parts by weight or more, or can be 0.03 parts by weight or more, with respect to 100 parts by weight of the polymer (A).

[0228] The technology disclosed herein can be preferably implemented in a manner using an isocyanate-based crosslinking agent as a crosslinking agent. An isocyanate-based crosslinking agent can also be used in combination with other crosslinking agents. In the manner of using an isocyanate-based crosslinking agent, the amount of the isocyanate-based crosslinking agent can be, for example, 0.005 parts by weight or more, 0.01 parts by weight or more, or 0.03 parts by weight or more, with respect to 100 parts by weight of the polymer (A). In addition, the amount of the isocyanate-based crosslinking agent can be, for example, 10 parts by weight or less, 5 parts by weight or less, 3 parts by weight or less, less than 2 parts by weight, less than 1 part by weight, less than 0.80 parts by weight, less than 0.60 parts by weight, less than 0.30 parts by weight, less than 0.10 parts by weight, or less than 0.08 parts by weight, with respect to 100 parts by weight of the polymer (A).

[0229] In order to make the crosslinking reaction proceed more efficiently, a crosslinking catalyst can also be used. As the crosslinking catalyst, metal-based crosslinking catalysts such as tetra-n-butyl titanate, tetraisopropyl titanate, iron (III) acetylacetonate (NACEM® Iron (III)), butyltin oxide, and dioctyltin laurate, and the like can be exemplified. Among them, tin-based crosslinking catalysts such as dioctyltin laurate are preferred. The amount of the crosslinking catalyst is not particularly limited. The amount of the crosslinking catalyst can be, for example, about 0.0001 parts by weight or more, about 0.001 parts by weight or more, or about 0.005 parts by weight or more, with respect to 100 parts by weight of the polymer (A). Furthermore, the amount can be, for example, about 1 parts by weight or less, about 0.1 parts by weight or less, or about 0.05 parts by weight or less.

[0230] In the adhesive composition used for forming the adhesive layer, a compound that undergoes keto-enol tautomerism can be contained as a crosslinking retarder as desired. For example, in an adhesive composition containing an isocyanate-based crosslinking agent or an adhesive composition that can be used by compounding an isocyanate-based crosslinking agent, a compound that undergoes keto-enol tautomerism can be preferably used. Thereby, an effect of extending the pot life of the adhesive composition can be exerted.

[0231] As the compound that undergoes keto-enol tautomerism, various β-dicarbonyl compounds can be used. As specific examples, β-diketones such as acetylacetone and 2,4-hexanedione; acetoacetic acid esters such as methyl acetoacetate and ethyl acetoacetate; propionyl acetoacetate and the like; isobutyryl acetoacetate and the like; malonic acid esters such as methyl malonate and ethyl malonate; and the like can be exemplified. As suitable compounds among them, acetylacetone and acetoacetic acid esters can be exemplified. The compound that undergoes keto-enol tautomerism can be used alone or in combination with two or more kinds.

[0232] The amount of the compound in which keto-enol tautomerism occurs can be, for example, 0.1 parts by weight or more and 20 parts by weight or less, preferably 0.5 parts by weight or more and 15 parts by weight or less, relative to 100 parts by weight of the polymer (A), and can be, for example, 1 part by weight or more and 10 parts by weight or less, or 1 part by weight or more and 5 parts by weight or less.

[0233] (Silane Coupling Agent)

[0234] A silane coupling agent can be contained in the adhesive layer of the adhesive sheet disclosed herein as desired. By using a silane coupling agent, the peeling strength of the adhesive sheet from a bonded object (e.g., a glass plate) can be improved. The adhesive layer containing a silane coupling agent can be suitably formed using an adhesive composition containing a silane coupling agent. In the adhesive composition, the silane coupling agent is preferably contained in a free form from the viewpoint of gelation inhibition and the like. In addition, in some modes, the silane coupling agent is preferably contained in the adhesive layer of the adhesive sheet disclosed herein in a free form. The silane coupling agent contained in the adhesive layer in this form can effectively contribute to the improvement of the peeling strength. Note that "free form" herein means that the silane coupling agent is not chemically bonded to other components contained in the adhesive composition or the adhesive layer.

[0235] As the silane coupling agent, a silicon compound having an epoxy structure such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, an amino-containing silicon compound such as 3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, a (meth)acryl group-containing silane coupling agent such as acetoacetyltrimethoxysilane, 3-acryloyloxypropyltrimethoxysilane, 3-methacryloyloxypropyltriethoxysilane, an isocyanate group-containing silane coupling agent such as 3-isocyanatopropyltriethoxysilane, and the like can be exemplified. In some modes, the above effects can be more preferably exerted by using a silane coupling agent having a trialkoxysilyl group. As a preferable silane coupling agent thereamong, 3-glycidoxypropyltrimethoxysilane and acetoacetyltrimethoxysilane can be exemplified.

[0236] The amount of the silane coupling agent used can be set in a manner to achieve the desired effect of use, and is not particularly limited. In several ways, the amount of the silane coupling agent can be, for example, 0.001 parts by weight or more, 0.01 parts by weight or more, 0.05 parts by weight or more, or 0.1 parts by weight or more, per 100 parts by weight of the polymer (A), from the viewpoint of achieving a higher effect. In addition, from the viewpoint of suppressing gelation of the adhesive composition and the like, it is appropriate to set the amount of the silane coupling agent to be 3 parts by weight or less, 1 part by weight or less, or 0.5 parts by weight or less, per 100 parts by weight of the polymer (A).

[0237] (Photo-polymerization initiator)

[0238] The adhesive layer of the adhesive sheet disclosed herein can contain a photo-polymerization initiator as needed, with the aim of increasing the photo-curing property or imparting the like. As the photo-polymerization initiator, the same photo-polymerization initiators exemplified as those usable in the synthesis of the polymer (A) can be used, and a ketal-based photo-polymerization initiator, an acetophenone-based photo-polymerization initiator, a benzoin ether-based photo-polymerization initiator, an acylphosphine oxide-based photo-polymerization initiator, an α-keto alcohol-based photo-polymerization initiator, an aromatic sulfonyl chloride-based photo-polymerization initiator, a photo-active oxime-based photo-polymerization initiator, a benzoin-based photo-polymerization initiator, a benzil-based photo-polymerization initiator, a benzophenone-based photo-polymerization initiator, a thioxanthone-based photo-polymerization initiator, or the like can be used. The photo-polymerization initiator can be used alone or in combination of two or more as appropriate.

[0239] Specific examples of the ketal-based photo-polymerization initiator include 2,2-dimethoxy-1,2-diphenylethane-1-ketone, and the like.

[0240] Specific examples of the acetophenone-based photo-polymerization initiator include 1-hydroxycyclohexyl-phenyl-ketone, 4-phenoxydichloroacetophenone, 4-tert-butyl-dichloroacetophenone, 1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-ketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-ketone, methoxyacetophenone, and the like.

[0241] Specific examples of the benzoin ether-based photo-polymerization initiator include benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and the like, and substituted benzoin ethers such as methyl anisole.

[0242] Specific examples of the acylphosphine oxide-based photopolymerization initiator include bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, bis(2,4,6-trimethylbenzoyl)-2,4-di-n-butoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide, and the like.

[0243] Specific examples of the α-ketol-based photopolymerization initiator include 2-methyl-2-hydroxypropiophenone, 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropane-1-one, and the like. Specific examples of the aromatic sulfonyl chloride-based photopolymerization initiator include 2-naphthalenesulfonyl chloride, and the like. Specific examples of the photoactive oxime-based photopolymerization initiator include 1-phenyl-1,1-propanedione-2-(O-ethoxycarbonyl)oxime, and the like. Specific examples of the benzoin-based photopolymerization initiator include benzoin, and the like. Specific examples of the benzil-based photopolymerization initiator include benzil, and the like.

[0244] Specific examples of the benzophenone-based photopolymerization initiator include benzophenone, benzoylbenzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinyl benzophenone, α-hydroxycyclohexyl phenyl ketone, and the like.

[0245] Specific examples of the thioxanthone-based photopolymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone, and the like.

[0246] The content of the photopolymerization initiator in the adhesive layer is not particularly limited and can be set in a manner that appropriately exerts a desired effect. Among several modes, the content of the photopolymerization initiator can be set to, for example, about 0.005 parts by weight or more, is appropriately set to 0.01 parts by weight or more, is preferably set to 0.05 parts by weight or more, can be set to 0.10 parts by weight or more, can be set to 0.15 parts by weight or more, and can be set to 0.20 parts by weight or more, with respect to 100 parts by weight of the polymer (A) contained in the adhesive layer. With an increase in the content of the photopolymerization initiator, there is a tendency that the photocurability of the adhesive layer is improved. In addition, the content of the photopolymerization initiator with respect to 100 parts by weight of the polymer (A) is appropriately set to 10 parts by weight or less, is preferably set to 7 parts by weight or less, can be set to 5 parts by weight or less, can be set to 3 parts by weight or less, can be set to 2 parts by weight or less, and can be set to 1 part by weight or less. From the viewpoint of improving the storage stability (for example, stability against light deterioration) of the adhesive sheet, it is advantageous that the content of the photopolymerization initiator is not too much.

[0247] The adhesive layer containing the photopolymerization initiator is preferably formed using an adhesive composition (e.g., a solvent-type adhesive composition) containing the photopolymerization initiator. The adhesive composition containing the photopolymerization initiator can be prepared, for example, by mixing other ingredients used in the composition with the photopolymerization initiator. In addition, in the case where the adhesive composition is prepared using a polymer (A) (e.g., an acrylic polymer (A)) synthesized (photopolymerized) in the presence of a photopolymerization initiator, the residue (unreacted substance) of the photopolymerization initiator used when the polymer (A) is synthesized can be used as a part or all of the photopolymerization initiator contained in the adhesive layer. The same applies to the case where an acrylic oligomer used as needed is a substance synthesized in the presence of a photopolymerization initiator. From the viewpoint of easiness in manufacturing management, the adhesive layer disclosed herein is preferably formed using an adhesive composition prepared by newly adding the above-mentioned amount of the photopolymerization initiator to other constituent ingredients.

[0248] The adhesive layer or the adhesive composition of the adhesive sheet disclosed herein can contain, as other optional ingredients, various additives commonly used in the field of adhesives, such as tackifying resins (e.g., rosin-based, petroleum-based, terpene-based, phenol-based, ketone-based, and the like), viscosity modifiers (e.g., thickeners), leveling agents, plasticizers, fillers, pigments, dyes, and the like, stabilizers, preservatives, anti-aging agents, and the like, as needed. As to such various additives, existing publicly known substances can be used by a conventional method, and are not particularly characteristic of the present application, and thus detailed description is omitted.

[0249] Note that the technology disclosed herein can exert good adhesion without using the above-mentioned tackifying resins. Therefore, in some modes, the content of the above-mentioned tackifying resins in the above-mentioned adhesive layer or adhesive composition can be, for example, less than 10 parts by weight, further less than 5 parts by weight, relative to 100 parts by weight of the polymer (A). The content of the above-mentioned tackifying resins can be less than 1 part by weight (e.g., less than 0.5 parts by weight), or less than 0.1 parts by weight (more than 0 parts by weight and less than 0.1 parts by weight). The above-mentioned adhesive layer or adhesive composition can be free of tackifying resins.

[0250] From the viewpoint of transparency, the amount of components other than the polymer (A) and the light-reactive monomer (B) described above, which are used as necessary, in the adhesive layer (or the adhesive composition used for forming the adhesive layer) is preferably limited. In the technology disclosed herein, it is appropriate that the amount of the components other than the polymer (A) and the light-reactive monomer (B) in the adhesive layer is about 30% by weight or less, about 15% by weight or less, and preferably about 12% by weight or less (for example, about 10% by weight or less). In the adhesive sheet in several modes, the amount of the components other than the polymer (A) and the light-reactive monomer (B) in the adhesive layer can be about 5% by weight or less, about 3% by weight or less, or about 1.5% by weight or less (for example, about 1% by weight or less).

[0251] <Adhesive composition>

[0252] The adhesive layer can be formed using an adhesive composition containing the monomer components described above in the form of a polymer, a non-polymer (i.e., a form in which the polymerizable functional group is not reacted), or a mixture thereof. The adhesive composition described above can be in various forms such as a composition in which the adhesive (adhesive component) is contained in an organic solvent (solvent-type adhesive composition), a composition in which the adhesive is dispersed in an aqueous solvent (water-dispersible adhesive composition), a composition prepared in a manner such that the adhesive is formed by curing using active energy rays such as ultraviolet rays, radiation rays, etc. (active energy ray-curable adhesive composition), a hot-melt-type adhesive composition in which the adhesive is formed when coated in a molten state and cooled to the vicinity of room temperature, etc. From the viewpoints of ease of preparation of the adhesive composition, ease of formation of the adhesive layer, etc., in several modes, it can be preferable to use a solvent-type adhesive composition. The solvent-type adhesive composition can be preferably prepared using the polymer (A) as a polymer obtained by solution polymerization of the monomer components.

[0253] Note that, in the present specification, "active energy rays" refer to energy rays having energy that can initiate chemical reactions such as polymerization reactions, crosslinking reactions, decomposition of initiators, etc. Examples of the active energy rays described herein include light such as ultraviolet rays, visible rays, infrared rays, α rays, β rays, γ rays, electron beams, neutron beams, X rays, and the like.

[0254] The above-mentioned adhesive composition is typically such that at least a part of the monomer components (which can be a part of the monomer species or a part of the components) of the composition is contained in the form of a polymer. The polymerization method in forming the above-mentioned polymer is not particularly limited, and various polymerization methods known in the art can be appropriately used. For example, thermal polymerization (typically in the presence of a thermal polymerization initiator) such as solution polymerization, emulsion polymerization, bulk polymerization, etc. can be appropriately used; photopolymerization (typically in the presence of a photopolymerization initiator) by irradiation of light such as ultraviolet rays, etc. can be appropriately used; radiation polymerization by irradiation of radiation such as β-rays, γ-rays, etc. can be appropriately used. Among these polymerization methods, the manner of polymerization is not particularly limited, and the known monomer supply method, polymerization conditions (temperature, time, pressure, light irradiation amount, radiation irradiation amount, etc.), materials other than monomers (polymerization initiator, surfactant, etc.), etc. can be appropriately selected.

[0255] At the time of polymerization, a known or conventional photopolymerization initiator, thermal polymerization initiator, etc. can be used depending on the polymerization method, the manner of polymerization, etc. Examples of the photopolymerization initiator and the thermal polymerization initiator are as described above, and thus repeated description is omitted. Such a polymerization initiator can be used alone or in combination of two or more as appropriate.

[0256] (Adhesive composition containing a polymer of monomer components and unreacted monomers)

[0257] The adhesive composition of several modes contains a polymerization reaction product of a monomer mixture containing at least a part of the monomer components (raw material monomers) of the composition. Typically, a part of the above-mentioned monomer components is contained in the form of a polymer, and the remaining part is contained in the form of unreacted monomers. The polymerization reaction product of the above-mentioned monomer mixture can be produced by polymerizing at least a part of the monomer mixture.

[0258] The above-mentioned polymerization reaction product is preferably a partial polymer of the above-mentioned monomer mixture. Such a partial polymer is a mixture of a polymer derived from the above-mentioned monomer mixture and unreacted monomers, and is typically in the form of a slurry (having a viscous liquid form). Hereinafter, the partial polymer having such a property is sometimes referred to as a "monomer slurry", a "polymer slurry", or simply a "slurry".

[0259] The polymerization method at the time of obtaining the above-mentioned polymerization reaction product is not particularly limited, and various polymerization methods as described above can be appropriately selected. From the viewpoint of efficiency and convenience, the photopolymerization method can be preferably used. At the time of using photopolymerization, the polymerization conditions such as the light irradiation amount (light quantity) of light can be used to easily control the polymerization conversion rate of the above-mentioned monomer mixture.

[0260] The polymerization conversion rate (monomer conversion rate) of the monomer mixture in the above-mentioned partially polymerized product is not particularly limited. The above-mentioned polymerization conversion rate can be set to, for example, about 70% by weight or less, and is preferably set to about 60% by weight or less. From the viewpoints of ease of production, coatability, and the like of the adhesive composition containing the above-mentioned partially polymerized product, the above-mentioned polymerization conversion rate is preferably about 50% by weight or less, and is more preferably about 40% by weight or less (for example, about 35% by weight or less). The lower limit of the polymerization conversion rate is not particularly limited, and is typically about 1% by weight or more, and is preferably set to about 5% by weight or more.

[0261] The adhesive composition containing the above-mentioned partially polymerized product of the monomer mixture can be easily obtained, for example, by partially polymerizing the monomer mixture containing all of the raw material monomers by an appropriate polymerization method (for example, photopolymerization). In the adhesive composition containing the above-mentioned partially polymerized product, other components (for example, a photopolymerization initiator, a multifunctional monomer, a crosslinking agent, an acrylic oligomer described later, and the like) used as needed can be compounded. The method of compounding such other components is not particularly limited, and the above-mentioned monomer mixture can be previously contained therein, or the above-mentioned partially polymerized product can be added thereto.

[0262] In addition, the adhesive composition disclosed herein can also be in a form in which a complete polymer of a monomer mixture containing a part of the kinds of monomer components (raw material monomers) is dissolved in the remaining kinds of monomers or a partially polymerized product thereof. Such a form of the adhesive composition is also included in the examples of the adhesive composition containing a polymer of monomer components and an un-polymerized product. Note that, in the present specification, the "complete polymer" refers to a polymer having a polymerization conversion rate of more than 95% by weight.

[0263] As the curing method (polymerization method) when the adhesive is formed from the adhesive composition thus containing the monomer component in the polymer and the un-polymer, a photopolymerization method can be preferably employed. For the adhesive composition containing the polymerization reaction product prepared by the photopolymerization method, it is particularly suitable to employ the photopolymerization method as the curing method thereof. The polymerization reaction product obtained by the photopolymerization method already contains a photopolymerization initiator, and therefore, when the adhesive composition containing the polymerization reaction product is further cured to form the adhesive, the photocuring can be performed even without adding a new photopolymerization initiator. Alternatively, the adhesive composition of the composition in which the photopolymerization initiator is added as needed to the polymerization reaction product prepared by the photopolymerization method can also be used. The added photopolymerization initiator can be the same as or different from the photopolymerization initiator used for the preparation of the polymerization reaction product. The adhesive composition prepared by a method other than the photopolymerization can be made photocurable by adding the photopolymerization initiator. The photocurable adhesive composition has the advantage that an adhesive layer of a relatively large thickness can be easily formed. In several preferred modes, the photopolymerization when the adhesive is formed from the adhesive composition can be performed by ultraviolet irradiation. The ultraviolet irradiation can use a known high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, or the like.

[0264] (Adhesive composition containing monomer component in the form of complete polymer)

[0265] The adhesive composition of the other several modes contains the monomer component of the adhesive composition in the form of complete polymer. Such an adhesive composition can be, for example, a solvent-type adhesive composition containing an acrylic polymer as the complete polymer of the monomer component in an organic solvent, a water-dispersible adhesive composition in which the above-described acrylic polymer is dispersed in an aqueous solvent, or the like.

[0266] (Thickness of adhesive layer)

[0267] The thickness of the adhesive layer is not particularly limited. The thickness of the adhesive layer can be, for example, about 1 μm to about 500 μm, and can be, for example, about 3 μm to about 500 μm. In some embodiments, it is appropriate for the thickness of the adhesive layer to be 5 μm or more, and can be, for example, 10 μm or more, preferably 20 μm or more, more preferably 25 μm or more, and can be more than 25 μm. When the thickness of the adhesive layer is large, there is a tendency for the stress dispersion ability in the adhesive layer to be high. This can advantageously contribute to a reduction in optical distortion. In addition, an adhesive layer having a large thickness has a tendency to have excellent height difference followability, and easily absorbs deformation caused by foreign matter and the like. There is a tendency for the impact resistance to also be improved. The technology disclosed herein can be preferably implemented in a manner in which the thickness of the adhesive layer is, for example, 30 μm or more. The thickness of the adhesive layer described above can be 35 μm or more, 40 μm or more, 45 μm or more, 50 μm or more, 75 μm or more, or 90 μm or more. On the other hand, when the thickness of the adhesive layer is large, the optical path through the adhesive layer also becomes long, and thus it becomes easy to observe optical distortion. Therefore, in some embodiments, it is appropriate for the thickness of the adhesive layer to be, for example, 200 μm or less, 150 μm or less, 120 μm or less, preferably 100 μm or less, more preferably 70 μm or less, further preferably 50 μm or less, or 35 μm or less. An adhesive layer having such a thickness can more effectively suppress deformation of the adhesive layer. When the technology disclosed herein is used, by having a configuration in which the adhesive layer has a thickness of, for example, 70 μm or less, the resistance to deformation is high, and a joint having high impact resistance can be formed.

[0268] Note that the thickness of the adhesive layer can be measured using a 1 / 1000 mm scale micrometer of a surface measuring instrument. In the case of a configuration in which, for example, a release film / adhesive layer / release film are stacked, the total thickness can be measured using a 1 / 1000 mm scale micrometer of a surface measuring instrument, and the thickness of the release film can be subtracted to calculate the thickness.

[0269] (Temperature at the peak of tan δ)

[0270] The adhesive that constitutes the adhesive layer disclosed herein preferably has a temperature at the peak of the loss tangent tan δ in the range of -50°C to 0°C. When an adhesive having a peak of tan δ in the low temperature region is used, good impact resistance is easily obtained. The temperature at the peak of the loss tangent tan δ of the adhesive can be found by the following method. That is, dynamic viscoelasticity measurement is performed under the same conditions as the measurement of the storage modulus at 25°C described below, and the storage modulus G' and the loss modulus G" are measured. Next, the loss tangent tan δ is calculated from the following equation: tan δ = G" / G', and the temperature dependence thereof is plotted, and thus the temperature corresponding to the peak thereof (the temperature at which the tan δ curve reaches a maximum) can be found.

[0271] Storage modulus at 25°C (25°C storage modulus)

[0272] The storage modulus at 25°C of the adhesive layer (25°C storage modulus) is appropriately set according to the use target and the use mode, and the like, and is not limited to a specific range. From the viewpoint of adhesive properties such as deformation resistance and heat resistance, the above-mentioned 25°C storage modulus is preferably about 4 x 10 4 Pa or more, more preferably about 6 x 10 4 Pa or more, more preferably about 8 x 10 4 Pa or more, more preferably about 1.0 x 10 5 Pa or more, more preferably about 1.2 x 10 5 Pa or more, more preferably about 1.5 x 10 5 Pa or more, more preferably about 1.8 x 10 5 Pa or more. The adhesive layer having a high 25°C storage modulus tends to have excellent resistance to compression deformation. In addition, a 25°C storage modulus of, for example, less than 1 x 10 7 Pa, about 1 x 10 6 Pa or less is appropriate. From the viewpoint of appropriately exhibiting adhesive properties such as adhesiveness, the above-mentioned 25°C storage modulus is preferably about 5.0 x 10 5 Pa or less, more preferably about 3.0 x 10 5 Pa or less, more preferably about 2.0 x 10 5 Pa or less, more preferably about 1.4 x 10 5 Pa or less, more preferably about 1.0 x 10 5 Pa or less. The storage modulus at 25°C of an adhesive sheet (representatively, a substrate-free adhesive sheet) is also preferably set to the above-mentioned example range. The 25°C storage modulus can be adjusted by the molecular weight, the molecular structure, the concentration, the crosslinking degree, and the like of the base polymer. The 25°C storage modulus is measured by the following method. The same applies in the Examples described later.

[0273] [25°C storage modulus]

[0274] A plurality of adhesive sheets or adhesive layers to be measured were overlapped to produce an adhesive layer having a thickness of about 2 mm. The adhesive layer was punched into a disc shape having a diameter of 7.9 mm, and the obtained sample was clamped and fixed with a parallel plate, and dynamic viscoelasticity measurement was performed with a viscoelasticity tester (for example, ARES manufactured by TA Instruments, Inc., or the like) under the following conditions to obtain the storage modulus G´(25°C) [Pa] at 25°C.

[0275] Measurement mode: shear mode

[0276] Temperature range: -70°C to 150°C

[0277] Temperature increase rate: 5°C / min

[0278] Measurement frequency: 1 Hz

[0279] (Gel fraction)

[0280] The gel fraction of the adhesive layer is appropriately set according to the use target, use method, and the like, and is not limited to a particular range. The gel fraction is, for example, appropriately about 99% by weight or less, or about 97% by weight or less. From the viewpoint of height difference followability and the like, in several preferred modes, the gel fraction is about 95% by weight or less, more preferably about 92% by weight or less, can be about 88% by weight or less, can be about 75% by weight or less, or can be about 65% by weight or less. An adhesive layer having the above gel fraction, for example, in the case where a print such as a mark is formed on the adherend surface, can follow the concave-convex of the print well without impairing the visual recognition. In addition, from the viewpoint of exhibiting good adhesion properties, viscoelastic properties, the gel fraction of the adhesive layer is, for example, appropriately about 10% by weight or more, or about 20% by weight or more. From the viewpoint of deformation resistance and the like, the gel fraction is preferably about 30% by weight or more, more preferably about 40% by weight, can be about 50% by weight or more, can be about 65% by weight or more, or can be about 75% by weight or more. The gel fraction of the adhesive sheet (representatively, a base material-free adhesive sheet) is also preferably set to the range of the above examples. The gel fraction can be adjusted by the molecular weight, molecular structure, concentration, crosslinking degree, and the like of the base polymer. The gel fraction is measured by the following method. The same applies in the examples described later.

[0281] [gel fraction]

[0282] A prescribed amount of the adhesive sample (weight Wg1) is wrapped in a pocket shape with a porous polytetrafluoroethylene film (weight Wg2) having an average pore diameter of 0.2 μm, and the mouth is bound with cotton thread (weight Wg3). As the above porous polytetrafluoroethylene (PTFE) film, a product with the trade name "Nitoflon (registered trademark) NTF1122" (average pore diameter 0.2 μm, porosity 75%, thickness 85 μm) available from Nitto Electric Industrial Co., Ltd. or an equivalent product thereof is used.

[0283] The wrapping is immersed in a sufficient amount of ethyl acetate, and after the sol component in the adhesive layer is only allowed to elute to the outside of the film at room temperature (representatively, 23°C) for 7 days, the wrapping is taken out, the ethyl acetate adhering to the outer surface is wiped off, and the wrapping is dried at 130°C for 2 hours, and the weight of the wrapping (Wg4) is measured. The gel fraction of the adhesive layer is calculated by substituting the values into the following formula.

[0284] Gel fraction (%) = [(Wg4 - Wg2 - Wg3) / Wg1] x 100

[0285] Note that the adhesive sheet disclosed herein includes an adhesive sheet in a state where the adhesive layer is photocured after being attached to an adherend, and thus at least for a photocurable adhesive sheet (for example, the adhesive sheet of Example 4 described later with the adhesive C), a sample after irradiation with ultraviolet rays under conditions of illuminance 300 mW / cm 2 , cumulative light amount 3000 mJ / cm 2 and 48-hour curing at 50°C is used for measurement of the peak top temperature of tan δ, the storage modulus at 25°C, the gel fraction, the total light transmittance, the haze value, the maximum height Rz of the adhesive surface, the arithmetic mean roughness Ra, the adhesive force, the elastic modulus based on the tensile test, and the impact resistance. For the above-mentioned ultraviolet irradiation treatment, in the case where the release film is transparent, it is preferable to perform the treatment in a state where the above-mentioned adhesive sheet (typically, the adhesive layer) is sandwiched between transparent release films.

[0286] <Supporting substrate>

[0287] The adhesive sheet of several modes can be in a state of an adhesive sheet with a supporting substrate including a supporting substrate. The material of the supporting substrate is not particularly limited, and can be appropriately selected depending on the use target, use mode, and the like of the adhesive sheet. As non-limiting examples of the supporting substrate that can be used, resin films such as a polyolefin film in which polypropylene, ethylene-propylene copolymer, or the like is the main component, a polyester film in which polyethylene terephthalate, polybutylene terephthalate, or the like is the main component, a polyvinyl chloride film in which polyvinyl chloride is the main component, and the like; a foamed sheet formed of a foamed body such as polyurethane foam, polyethylene foam, polychloroprene foam, and the like; a fabric and a nonwoven fabric formed of various fiber-like substances (which can be natural fibers such as hemp, cotton, and the like, synthetic fibers such as polyester, vinylon, and the like, semi-synthetic fibers such as acetate fibers, and the like) alone or by blending, and the like; paper such as Japanese paper, fine paper, kraft paper, crepe paper, and the like; a metal foil such as an aluminum foil, a copper foil, and the like; and the like. It can also be a supporting substrate composed of a combination of these. As examples of such a supporting substrate of a combined structure, for example, a supporting substrate of a structure in which a metal layer (for example, a metal foil, a continuous or discontinuous metal sputtered layer, a metal vapor-deposited layer, a metal plated layer, and the like), a metal oxide layer, and the like are layered with the above-mentioned resin film, a resin sheet obtained by reinforcing with inorganic fibers such as glass cloth, and the like can be mentioned. The above-mentioned supporting substrate can correspond to the optical member (for example, an optical film) described later, and can also be a transparent member formed of a transparent material (for example, a resin material having transparency, glass, and the like).

[0288] As the support substrate of the adhesive sheet disclosed herein, various films (hereinafter also referred to as support films) can be preferably used. The support film described above can be a porous film such as a foamed film, a nonwoven fabric sheet, or the like, can be a non-porous film, or can be a film having a structure in which a porous layer and a non-porous layer are stacked. Among them, as the support film described above, a support film including a resin film that can independently maintain a shape (self-supporting or non-dependent) as a base film can be preferably used. Here, the "resin film" refers to a non-porous structure and is typically a resin film substantially free of bubbles (non-porous). Thus, the resin film described above is a concept distinct from a foamed film and a nonwoven fabric. The resin film described above can have a single-layer structure or a multilayer structure of two or more layers (for example, a three-layer structure).

[0289] As the resin material constituting the resin film, for example, polyester, polyolefin, polycycloolefin derived from a monomer having an aliphatic ring structure such as norbornene structure, nylon 6, nylon 66, polyamide (PA) such as partially aromatic polyamide, polyimide (PI), polyamide-imide (PAI), polyether ether ketone (PEEK), polyether sulfone (PES), polyphenylene sulfide (PPS), polycarbonate (PC), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), polystyrene, polyvinyl chloride, polyvinylidene chloride, fluororesin such as polytetrafluoroethylene (PTFE), acrylic resin such as polymethyl methacrylate, cellulose-based polymer such as diacetyl cellulose and triacetyl cellulose, vinyl acetal-based polymer, acrylate-based polymer, polyoxymethylene-based polymer, and epoxy-based polymer can be used. The resin film described above can be formed using a resin material containing only one of such resins, or can be formed using a resin material obtained by blending two or more of such resins. The resin film described above can be unstretched or can be stretched (for example, uniaxially stretched or biaxially stretched).

[0290] As a preferable example of the resin material constituting the resin film, a polyester-based resin, a PPS resin, and a polyolefin-based resin can be exemplified. Here, the polyester-based resin refers to a resin containing polyester in a proportion of more than 50% by weight. Similarly, the PPS resin refers to a resin containing PPS in a proportion of more than 50% by weight, and the polyolefin-based resin refers to a resin containing polyolefin in a proportion of more than 50% by weight.

[0291] As the polyester-based resin, a polyester-based resin containing a polyester obtained by polycondensation of a dicarboxylic acid and a diol as a main component is typically used. As a specific example of the polyester-based resin, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate, and the like can be exemplified.

[0292] As the polyolefin resin, one kind of polyolefin alone or two or more kinds of polyolefins in combination can be used. The polyolefin can be, for example, a homopolymer of an α-olefin, a copolymer of two or more kinds of α-olefins, a copolymer of one or two or more kinds of α-olefins and another vinyl monomer, or the like. As specific examples, there can be mentioned polyethylene (PE), polypropylene (PP), poly-1-butene, poly-4-methyl-1-pentene, ethylene-propylene rubber (EPR) such as an ethylene-propylene copolymer, an ethylene-propylene-butene copolymer, an ethylene-butene copolymer, an ethylene- vinyl alcohol copolymer, an ethylene-ethyl acrylate copolymer, and the like. Both a low-density (LD) polyolefin and a high-density (HD) polyolefin can be used. As examples of the polyolefin resin film, there can be mentioned a non-stretched polypropylene (CPP) film, a biaxially-stretched polypropylene (OPP) film, a low-density polyethylene (LDPE) film, a linear low-density polyethylene (LLDPE) film, a medium-density polyethylene (MDPE) film, a high-density polyethylene (HDPE) film, a polyethylene (PE) film obtained by blending two or more kinds of polyethylenes (PE), a PP / PE blend film obtained by blending polypropylene (PP) and polyethylene (PE), and the like.

[0293] As specific examples of the resin film which can be preferably used as the support substrate, there can be mentioned a PET film, a PEN film, a PPS film, a PEEK film, a CPP film, and an OPP film. As examples which are preferred from the viewpoint of strength, there can be mentioned a PET film, a PEN film, a PPS film, and a PEEK film. As examples which are preferred from the viewpoints of easiness of acquisition, dimensional stability, optical properties, and the like, there can be mentioned a PET film.

[0294] In the resin film, known additives such as a light stabilizer, an antioxidant, an antistatic agent, a coloring agent (dye, pigment, and the like), a filler, a slip agent, an anti-blocking agent, and the like can be compounded as needed. The compounding amount of the additive is not particularly limited and can be appropriately set depending on the purpose of the adhesive sheet and the like.

[0295] The method of producing the resin film is not particularly limited. For example, a generally known resin film molding method such as extrusion molding, inflation molding, T-die casting molding, calender roll molding, and the like can be appropriately used.

[0296] The support base material can be a support film consisting essentially of the resin film. Alternatively, the support base material can be a support film including an auxiliary layer in addition to the resin film. The auxiliary layer can be disposed on the adhesive layer side of the resin film, on the side opposite the adhesive layer, or on both sides of the resin film. Examples of the auxiliary layer include an optical property adjustment layer (e.g., a colored layer, an antireflection layer), a decorative layer (e.g., a printed layer, a laminated layer, a continuous or discontinuous metal layer, a continuous or discontinuous metal oxide layer, etc.) that imparts a desired appearance to the support base material or the adhesive sheet, a conductive layer, an antistatic layer, a primer layer, a release layer, and the like.

[0297] In some embodiments, the support base material is preferably a plastic film having transparency. In such embodiments, it is appropriate for the total light transmittance of the support base material to be, for example, about 50% or greater, for example, about 70% or greater. From the viewpoint of visual recognition of the adherend through the adhesive sheet, in some preferred embodiments, the total light transmittance of the support base material is about 85% or greater, more preferably about 90% or greater. The upper limit of the total light transmittance can be, in practice, about 95% or less, or about 94% or less (e.g., 93% or less).

[0298] Note that the total light transmittance of the support base material can be measured using a haze meter. As the haze meter, a device manufactured by Murakami Color Research Laboratory, with the trade name "HM-150N" or an equivalent product thereof can be used.

[0299] The thickness of the support base material is not particularly limited and can be selected according to the target use, use mode, and the like of the adhesive sheet. The thickness of the support base material can be, for example, 1000 μm or less, and from the viewpoint of handling properties (e.g., ease of winding), it is appropriate for the thickness to be 500 μm or less, preferably 300 μm or less, can be 100 μm or less, can be 70 μm or less, can be 50 μm or less, can be 25 μm or less, can be 10 μm or less, can be 5 μm or less. As the thickness of the support base material decreases, there is a tendency for the softness of the adhesive sheet and the followability to the surface shape of the adherend to improve. Alternatively, from the viewpoint of handling properties, processability, and the like, the thickness of the support base material can be, for example, 2 μm or more, or more than 5 μm or more than 10 μm. In some embodiments, the thickness of the support base material can be, for example, 20 μm or more, can be 35 μm or more, or can be 55 μm or more.

[0300] As for the surface of the support substrate on the side in contact with the adhesive layer, a surface treatment known in the art such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, application of a primer (undercoat), antistatic treatment, etc. can be performed as needed. Such a surface treatment can be a treatment for improving the adhesion of the support substrate to the adhesive layer, in other words, the anchoring of the adhesive layer to the support substrate. The composition of the primer is not particularly limited and can be appropriately selected from known compositions. The thickness of the primer layer is not particularly limited and is preferably about 0.01 μm to about 1 μm, more preferably about 0.1 μm to about 1 μm.

[0301] <Method for producing an adhesive sheet with a release film>

[0302] The method for producing the adhesive sheet with a release film disclosed herein is not particularly limited. For example, an adhesive composition can be applied to the release surface of a release film, dried (e.g., heat-dried) or cured, thereby forming an adhesive layer on the release surface, and a different release film can be laminated on the surface of the adhesive layer on the side opposite to the above-mentioned release surface, thereby obtaining an adhesive sheet with a release film. Alternatively, an adhesive composition sandwiched between two release films can be dried or cured to form an adhesive layer, thereby obtaining an adhesive sheet with a release film. In the case of an adhesive sheet having a support substrate, for example, a method in which an adhesive composition is applied to the support substrate and dried or cured to form an adhesive layer (direct method) can be employed. Alternatively, a method in which an adhesive composition is applied to a surface having a release property (release surface) and dried to form an adhesive layer on the surface, and the adhesive layer is transferred to a support substrate (transfer method) can be employed.

[0303] The curing treatment can include cross-linking (e.g., cross-linking based on the reaction of the above-mentioned cross-linking agent), cooling, etc. In the case where two or more curing treatments are performed, they can be performed simultaneously or stepwise. As the method for applying the adhesive composition, various methods known in the art can be used. Specifically, for example, roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spraying, dip roll coating, bar coating, blade coating, air knife coating, curtain coating, lip coating, extrusion coating based on a die coater, etc. can be mentioned.

[0304] The adhesive sheet with a release film disclosed herein can be suitably manufactured by a method comprising: drying or curing a liquid film of the adhesive composition on a release surface of a release film to form an adhesive layer. When this method is used, the adhesive composition in a state of fluidity (liquid film) is dried or cured in contact with the release surface, and thus the smoothness of the surface of the adhesive layer formed in contact with the release surface can be controlled with good precision. The release surface is typically one in which the maximum height (Rz) is limited to a prescribed value or less, and by using a release film having such a release surface, an adhesive surface having high smoothness can be stably manufactured (with good reproducibility).

[0305] The adhesive sheet with a release film disclosed herein can be suitably manufactured by a method comprising: drying or curing a liquid film of the adhesive composition on a release surface of a release film to form an adhesive layer. When this method is used, the adhesive composition in a state of fluidity (liquid film) is dried or cured in contact with the release surface, and thus the smoothness of the surface of the adhesive layer formed in contact with the release surface can be controlled with good precision. The release surface is typically one in which the maximum height (Rz) is limited to a prescribed value or less, and by using a release film having such a release surface, an adhesive surface having high smoothness can be stably manufactured (with good reproducibility).

[0306] The total thickness of the adhesive sheet with a release film disclosed herein is not particularly limited, and can be, for example, about 30 μm to 1500 μm. Here, the total thickness of the adhesive sheet with a release film refers to the total thickness of the adhesive sheet with a release film composed of at least one release film (including the first release film and the second release film) and the adhesive sheet. In some modes, the total thickness of the adhesive sheet with a release film can be, for example, 60 μm or more, 80 μm or more, 105 μm or more, 125 μm or more, or 140 μm or more. The total thickness of the adhesive sheet with a release film can be, for example, 1000 μm or less, 500 μm or less, or 300 μm or less.

[0307] <Coiled Body>

[0308] According to the present specification, a wound body (tape-attached film-attached adhesive sheet roll) of the tape-attached film-attached adhesive sheet disclosed herein in a wound state is provided. This wound body is typically a wound body comprising a core (winding core) and the tape-attached film-attached adhesive sheet wound around the core. The shape of the core is not particularly limited, and can be, for example, a solid cylindrical shape, a hollow cylindrical shape (i.e., a cylindrical shape), a hollow or solid polygonal cylindrical shape, or the like. From the viewpoint of improving the handling properties of the wound body, a core having a hollow cylindrical shape or a hollow polygonal cylindrical shape can be preferably used. A core having a cylindrical shape is particularly preferred.

[0309]

[0310] The method of adhering the adhesive sheet disclosed herein to an adherend is not particularly limited. A known or conventional pressure bonding method can be used depending on the use target and use method. In several preferred modes, the adhesive sheet can be used in a mode in which the adhesive sheet is adhered to the above-described adherend by a method including light curing the adhesive layer after being adhered to the adherend. By adhering the adhesive sheet to the adherend, a laminated adherend having the adhesive sheet laminated is formed. By light curing the adhesive layer of the adhesive sheet, a laminate of the adhesive sheet having the adhesive layer cured and the above-described adherend is obtained. Thus, according to the present specification, a method of adhering an adhesive sheet is provided, which sequentially includes: adhering any of the adhesive sheets disclosed herein to an adherend, and irradiating the above-described adhesive sheet with ultraviolet rays to light cure the above-described adhesive layer.

[0311]

[0312] The adhesive sheet disclosed herein can be used for fixing, joining, molding, decorating, protecting, supporting, or the like of members constituting various products. The material constituting at least the surface of the above-described member can be, for example, glass such as alkali glass or non-alkali glass; a metal material such as stainless steel (SUS) or aluminum; a resin material such as an acrylic resin, an ABS resin, a polycarbonate resin, a polyimide resin, a polyester resin such as PET, or a polystyrene resin. The above-described member can be, for example, a member constituting various mobile devices (portable devices), automobiles, home electric appliances, or the like. In addition, the surface of the above-described member to which the adhesive sheet is adhered can be a coated surface based on an acrylic, a polyester, an alkyd, a melamine, a urethane, an acid anhydride epoxy crosslinking, or a composite thereof (for example, an acrylic melamine, an alkyd melamine), or a plated surface of a galvanized steel sheet or the like. In addition, the above-described member can be, for example, a resin film, an object having a continuous or discontinuous inorganic layer (which can be a metal layer, a metal oxide layer, or the like) on a resin film.

[0313] ​​As an example of the preferable use, an optical use can be exemplified. More specifically, for example, an optical adhesive sheet used in an application of an optical member (optical member application), a manufacturing application of a product using the optical member (optical product), and the like, the adhesive sheet disclosed herein can be preferably used.

[0314] The optical member described above refers to a member having an optical property (for example, a polarizing property, a light refractive property, a light diffractive property, an optical activity, and the like). As the optical member described above, there is no particular limitation as long as it is a member having an optical property, and for example, a member constituting a display device (an image display device), an input device, or the like (an optical device) or a member used in these devices can be exemplified, and for example, a polarizing plate, a wavelength plate, a phase difference plate, an optical compensation film, a brightness enhancement film, a light guide plate, a reflective film, an anti-reflective film, a hard coat (HC) film, an impact absorbing film, a stain-proof film, a photochromic film, a light control film, a transparent conductive film (ITO film), and further, a member in which these are stacked (sometimes, these are collectively referred to as "functional film.") and the like can be exemplified. Note that the "plate" and the "film" described above each include a plate-like shape, a film-like shape, a sheet-like shape, and the like, and for example, a "polarizing film" includes a "polarizing plate", a "polarizing sheet", and the like.

[0315] As the display device described above, for example, a liquid crystal display device, an organic EL (electroluminescence) display device, a PDP (plasma display panel), electronic paper, and the like can be exemplified. In addition, as the input device described above, a touch panel and the like can be exemplified.

[0316] As the optical member described above, there is no particular limitation, and for example, a member (for example, a sheet-like member, a film-like member, a plate-like member, and the like) formed of glass, an acrylic resin, polycarbonate, a transparent polyimide, PET, and the like can be exemplified.

[0317] As a method of attaching optical members using the adhesive sheet disclosed herein, there is no particular limitation, and for example, it can be (1) a method of attaching optical members to each other with the use of the adhesive sheet disclosed herein, (2) a method of attaching an optical member to a member other than an optical member with the use of the adhesive sheet disclosed herein, and it can also be (3) a method of attaching the adhesive sheet disclosed herein in a form containing an optical member to an optical member or a member other than an optical member. Note that in the method of (3) above, the adhesive sheet in a form containing an optical member can be, for example, an adhesive sheet in which a support substrate is an optical member (for example, an optical film). The adhesive sheet in a form containing an optical member as a support substrate can also be understood as an adhesive-type optical member (for example, an adhesive-type optical film). In addition, the adhesive sheet disclosed herein is an adhesive sheet of a type having a support substrate, and in the case where the functional film described above is used as the support substrate described above, the adhesive sheet disclosed herein can also be understood as an "adhesive-type functional film" having an adhesive layer disclosed herein on at least one side of the functional film.

[0318] The adhesive sheet disclosed herein can be preferably used for the purpose of pasting to a decorative film. Here, the decorative film refers to a film having a design (including color, hue, pattern, and further, letter information such as a logo on its surface (decorative surface), and is also called a design film, a decorative film. The decorative film described above includes a member that assumes a role of decoration and protection while maintaining visual recognition of an image display device, an input device. As the decorative film, for example, a film having a decorative layer (a printed layer, a laminated layer, a colored layer, a glossy layer, a continuous or discontinuous inorganic layer (a metal layer, a metal oxide layer, and the like)) that imparts a desired appearance can be exemplified. The decorative film described above can have a design on its surface and exhibit good shielding properties.

[0319] The above decorative film can have a decorative layer. As examples of the above decorative layer, for example, a printed layer that imparts a desired appearance, a lamination layer, a colored layer, a glossy layer, a continuous or discontinuous inorganic layer, and the like can be listed. As the continuous or discontinuous inorganic layer, a continuous or discontinuous metal layer, a continuous or discontinuous metal oxide layer, a laminate of a continuous or discontinuous metal layer and a metal oxide layer, a continuous or discontinuous metal / metal oxide composite layer, and the like can be listed. As the metal, for example, aluminum, zinc, lead, copper, silver, alloys thereof, and the like can be listed. As the metal oxide, for example, chromium oxide, indium oxide, zinc oxide, titanium oxide, and the like can be listed. The metal layer and the metal oxide layer can be formed by evaporation, sputtering, or the like. As one representative example of the decorative film, a metallic color film can be listed. The metallic color decorative film can have electromagnetic wave permeability in addition to the metallic gloss. As such a decorative film, for example, an electromagnetic wave permeable metallic gloss member described in Japanese Patent Application Publication No. 2018-69462, Japanese Patent Application Publication No. 2019-123238, Japanese Patent Application Publication No. 2019-188805, and the like can be listed.

[0320] In addition, the decorative film specifically further has a base material layer, and can have the base material layer and a decorative layer that covers at least a portion of at least one surface of the base material layer. As the base material layer, various resin films such as the above-described plastic film can be used. Among them, a resin film formed of a polyester-based resin such as PET, a polyolefin-based resin, a polycarbonate-based resin, and a (meth)acrylic-based resin is preferred. The thickness of the base material layer is not particularly limited, and is, for example, about 5 to 250 μm. The above-described decorative layer can be disposed on the adhesive sheet side of the above-described base material layer, on the side opposite to the adhesive sheet side, or on both sides of the above-described base material layer.

[0321] In the decorative film including the decorative layer, the thickness of the decorative layer is preferably in the range of about 1 to 1000 nm, and can be, for example, about 1 to 300 nm, or about 1 to 200 nm. In addition, the sheet resistance of the above-described decorative layer is preferably 100 Ω / D or more, and can be, for example, 250 Ω / D or more, or 1000 Ω / D or more. The decorative film having such a decorative layer can be a decorative film having electromagnetic wave permeability, and thus, for example, can be preferably used for various uses that require electromagnetic wave permeability such as portable electronic devices. The upper limit of the sheet resistance of the above-described decorative layer is not particularly limited, and can be, for example, 1 x 10 16 Ω / D or less. Note that the above-described sheet resistance can be measured according to the overcurrent measurement method described in JIS Z 2316.

[0322] The design surface of the decorative film described above can have a flat plane, or can have a concave-convex caused by printing, engraving, or the like. The adhesive sheet disclosed herein can be an adhesive sheet having excellent height difference followability, and thus can be well adhered to the surface of the decorative film having the concave-convex described above.

[0323] In addition, the adhesive sheet disclosed herein is excellent in visual recognition of the adherend based on high surface smoothness, and thus can be preferably used for an application of being attached to a transparent member, an application of fixing two members of which at least one is a transparent member. As such an application of fixing members, a mode in which one of the members is a transparent member and the other is a member having an image display surface, a decorative surface, or a colored surface can be exemplified. In other words, the adhesive sheet disclosed herein is preferably used for fixing a member having an image display surface, a decorative surface, or a colored surface to a transparent member. As the image display surface, the liquid crystal display surface, the organic EL display surface, a PDP, electronic paper, or the like described above can be exemplified. As the decorative surface, the decorative surface of the decorative film described above can be exemplified. As the colored surface, the surface of a light-shielding film, a shielding film can be exemplified. As the transparent member, a member formed of a transparent material including glass, an acrylic resin, polycarbonate, PET, or the like can be used. In such a configuration, by using an adhesive sheet having, for example, a total light transmittance and a haze value of a predetermined value or more, the image display surface, the decorative surface, or the colored surface of the adherend described above can be visually recognized well through the adhesive sheet and the transparent member.

[0324] The transparent member described above can be a flat plate, but can have a concave-convex such as printing, engraving, or the like on the adhesive sheet attachment surface, or can have a three-dimensional shape as a whole. The adhesive sheet disclosed herein can be an adhesive sheet having excellent height difference followability, and thus can be well adhered to the surface of the transparent member having the concave-convex described above. In addition, the transparent member having a three-dimensional shape can have a bending portion bent in a straight line shape or a curved portion curved in a curved line shape in the cross section in the thickness direction thereof. The transparent member described above can have a shape in which the adhesive sheet attachment surface is bent or curved in one direction, or can have a shape in which the adhesive sheet attachment surface is bent or curved in one direction and a direction intersecting (for example, orthogonal to) the one direction. In other words, the adhesive sheet attachment surface of the transparent member described above can have a two-dimensional three-dimensional structure or a three-dimensional three-dimensional structure.

[0325] The adhesive sheet disclosed herein can be preferably used for a portable electronic device. In the portable electronic device described above, the use for attachment to a transparent member, the use for fixing a member of which at least one side is a transparent member, and the like can be preferably used. In addition, in the portable electronic device described above, the use for attachment to an image display surface, a decorative surface, a colored surface, and the like can be preferably used. For example, the adhesive sheet disclosed herein can be preferably used for the use for fixing an image display surface, a decorative surface, a colored surface, and the like of a constituent member (for example, a decorative film) on the inner side of a transparent case as a transparent member. With such a constitution, it is possible to visually recognize the decorative surface and the like from the outside of the case, and on the other hand, for example, in a manner in which a member having a colored surface is used, it is possible to have internal shielding properties, and thus it can be particularly suitable as an outer structure such as a housing.

[0326] Non-limiting examples of the portable electronic device described above include a mobile phone, a smartphone, a tablet personal computer, a notebook personal computer, various wearable devices (for example, a wrist-worn type in which a watch is worn on a wrist, a modular type in which a module is worn on a part of a body with a clip, a band, or the like, an eyewear type including a glasses type (a monocular type, a binocular type. A helmet type is also included.), a clothing type in which a module is mounted to a shirt, a sock, a hat, or the like in the form of a piece of jewelry, an ear-worn type in which an earphone is mounted to an ear, and the like), a digital still camera, a digital video camera, a sound equipment (a portable music player, a voice recorder, and the like), a calculator (a desk calculator, and the like), a portable game device, an electronic dictionary, an electronic organizer, an electronic book, an in-vehicle information device, a portable radio, a portable television, a portable printer, a portable scanner, a portable modem, and the like. Note that "portable" in the present specification is not sufficient if it means only that it can be carried, and it means that it has portability at a level that a person (a standard adult) can move relatively easily.

[0327] Note that the matters disclosed in the present specification include the following aspects.

[0328] 〔1〕 An adhesive sheet with a release film, comprising: an adhesive sheet having an adhesive layer, and a release film laminated on the adhesive surface of the adhesive sheet,

[0329] The maximum height Rz of the adhesive surface side surface of the aforementioned release film is 400 nm or less.

[0330] 〔2〕 The adhesive sheet with a release film according to the aforementioned item 〔1〕, wherein the arithmetic mean roughness Ra of the adhesive surface side surface of the aforementioned release film is 30 nm or less.

[0331] 〔3〕 The adhesive sheet with a release film according to the aforementioned item 〔1〕 or 〔2〕, wherein the peeling force of the aforementioned release film with respect to the aforementioned adhesive sheet is 1 N / 50 mm or less.

[0332] 〔4〕 The adhesive sheet with release film according to any one of the above items 1 to 3, wherein the thickness of the release film is in the range of 50 to 125 μm.

[0333] 〔5〕 The adhesive sheet with release film according to any one of the above items 1 to 4, wherein the total light transmittance of the adhesive sheet is 85% or more and the haze value is 1% or less.

[0334] 〔6〕 The adhesive sheet with release film according to any one of the above items 1 to 5, wherein the adhesive sheet is a single-coated adhesive sheet having the adhesive layer and a support substrate laminated on one face of the adhesive layer.

[0335] 〔7〕 The adhesive sheet with release film according to any one of the above items 1 to 5, wherein the adhesive sheet is a double-coated adhesive sheet having a first adhesive face and a second adhesive face,

[0336] a first release film disposed on the first adhesive face and a second release film disposed on the second adhesive face,

[0337] the maximum height Rz1 of the first adhesive face side surface S1 of the first release film and the maximum height Rz2 of the second adhesive face side surface S2 of the second release film are each 400 nm or less.

[0338] 〔8〕 The adhesive sheet with release film according to any one of the above items 1 to 5, wherein the adhesive sheet is a double-coated adhesive sheet having a first adhesive face and a second adhesive face,

[0339] the release film is a double release film having a first release face and a second release face,

[0340] the maximum height Rz1 of the first release face of the release film and the maximum height Rz2 of the second release face of the release film are each 400 nm or less.

[0341] 〔9〕 The adhesive sheet with release film according to any one of the above items 1 to 8, wherein the adhesive layer is an acrylic adhesive layer.

[0342] 〔10〕 The adhesive sheet with release film according to any one of the above items 1 to 9, wherein the gel fraction of the adhesive layer is 30 to 95% by weight.

[0343] 〔11〕 The adhesive sheet with release film according to any one of the above items 1 to 10, wherein the storage modulus of the adhesive sheet at 25°C is 4 x 10 4 Pa or more.

[0344] 〔12〕 The adhesive sheet with release film according to any one of the above items 1 to 11, wherein the thickness of the adhesive sheet is 5 to 100 μm.

[0345] 〔13〕 The adhesive sheet with release film according to any one of the above items 1 to 12, wherein the elastic modulus of the adhesive sheet is 3.0 MPa or more as measured by the following tensile test.

[0346] [Tensile test]

[0347] The adhesive layer of the adhesive sheet was irradiated with ultraviolet rays under conditions of illuminance 300 mW / cm 2 , cumulative light amount 3000 mJ / cm 2 , and then, after aging for 48 hours at 50°C, the adhesive layer was cut into a size of 10 mm in width and 150 mm in length to produce a test piece. The test piece was subjected to a tensile test using a tensile tester under conditions of chuck distance 120 mm and tensile speed 50 mm / min in an environment of 23°C and 50% RH, and a stress-displacement curve was obtained. The elastic modulus [MPa] was calculated from the initial slope of the curve.

[0348] 〔14〕 The adhesive sheet with release film according to any one of the above items 1 to 13, wherein the impact resistance of the adhesive sheet is 2.0 J / 10 mm 2 or more as measured by the following shear impact test.

[0349] [Shear impact test]

[0350] A shear impact test was performed using a pendulum-type adhesive shear impact tester based on JIS K6855. As a measurement sample, a sample was used which was obtained by adhering the first face of the adhesive sheet of 10 mm square to the central portion of a chemically strengthened glass plate of 25 mm square and 1.7 mm in thickness, then adhering the second face of the adhesive sheet to the central portion of a stainless steel plate (SUS304BA plate) of 40 mm square with a pressure bonding of 5 N for 10 seconds, followed by autoclave treatment (50°C, 0.5 MPa, 15 minutes), and then, irradiating the glass plate side with ultraviolet rays under conditions of illuminance 300 mW / cm 2 , cumulative light amount 3000 mJ / cm 2 , and then, aging for 48 hours at 50°C.

[0351] The aforementioned stainless steel plate was fixed with the aforementioned measurement sample on the lower side, and the absorption energy [J] when a hammer was hit on the outer circumferential side of the aforementioned glass plate at a hammer energy of 2.75 J and a hammer speed of 3.5 m / sec in an environment of 23°C, 50% RH was measured, and thus the impact resistance [J / 10 mm] was calculated. 2

[0352] 〔15〕The adhesive sheet with a release film according to any one of the above <1> to <14>, wherein the adhesive layer of the adhesive sheet contains a polymer (A) and a photoreactive monomer (B).

[0353] 〔16〕The adhesive sheet with a release film according to the above <15>, wherein the photoreactive monomer (B) contains a compound B1 having a ring structure and two or more ethylenic unsaturated groups in a molecule, the molecular weight of the compound B1 being 100 g / mol or more per 1 ethylenic unsaturated group.

[0354] 〔17〕The adhesive sheet with a release film according to the above <16>, wherein the compound B1 contains at least one structure selected from the group consisting of a bisphenol A structure, a bisphenol F structure, and a bisphenol E structure in a molecule.

[0355] 〔18〕The adhesive sheet with a release film according to the above <16> or <17>, wherein the compound B1 contains an aliphatic ring structure as the ring structure.

[0356] 〔19〕The adhesive sheet with a release film according to any one of the above <16> to <18>, wherein the compound B1 contains at least one structure selected from the group consisting of a hydroxyl group and an amino group in a molecule.

[0357] 〔20〕The adhesive sheet with a release film according to any one of the above <16> to <19>, wherein the content of the compound B1 in the adhesive layer is 0.5 parts by weight or more and 60 parts by weight or less with respect to 100 parts by weight of the polymer (A).

[0358] 〔21〕The adhesive sheet with a release film according to any one of the above <16> to <20>, wherein the adhesive layer contains the compound B1 and a compound B2 having a functional group number of two or more and not containing a ring structure in a molecule as the photoreactive monomer (B).

[0359] 〔22〕The adhesive sheet with a release film according to the above <21>, wherein the functional group equivalent weight of the compound B2 is smaller than the functional group equivalent weight of the compound B1.

[0360] ​〔23〕 The adhesive sheet with release film according to any one of the above items 21 to 22, wherein the functional group equivalent of the compound B2 is 400 g / mol or less.

[0361] 〔24〕 The adhesive sheet with release film according to any one of the above items 21 to 23, wherein the content of the compound B2 in the adhesive layer is 25 parts by weight or less with respect to 100 parts by weight of the polymer (A).

[0362] 〔25〕 The adhesive sheet with release film according to any one of the above items 15 to 24, wherein the content of the photoreactive monomer (B) in the adhesive layer is 1 part by weight or more and 80 parts by weight or less with respect to 100 parts by weight of the polymer (A).

[0363] 〔26〕 The adhesive sheet with release film according to any one of the above items 15 to 25, wherein the polymer (A) is an acrylic polymer.

[0364] 〔27〕 The adhesive sheet with release film according to the above item 26, wherein the monomer component constituting the acrylic polymer contains a monomer having a ring containing a nitrogen atom.

[0365] 〔28〕 The adhesive sheet with release film according to any one of the above items 15 to 27, wherein the glass transition temperature of the polymer (A) is -45°C or more and less than 0°C.

[0366] 〔29〕 The adhesive sheet with release film according to any one of the above items 15 to 28, wherein the adhesive layer is crosslinked with a crosslinking agent.

[0367] 〔30〕 The adhesive sheet with release film according to any one of the above items 15 to 29, wherein the adhesive layer contains a photopolymerization initiator.

[0368] 〔31〕 The adhesive sheet with release film according to any one of the above items 15 to 30, wherein the adhesive layer contains a silane coupling agent.

[0369] 〔32〕 The adhesive sheet with release film according to any one of the above items 1 to 31, wherein the adhesive sheet has an adhesive force to glass of 1.0 N / 20 mm or more.

[0370] 〔33〕 The adhesive sheet with release film according to any one of the above items 1 to 32, which is used for fixing a member having an image display surface, a decorative surface, or a colored surface to a transparent member.

[0371]

[34] An adhesive sheet roll with a release film is formed by winding the adhesive sheet with a release film as described in any one of [1] to

[33] above.

[0372] Example

[0373] The following describes several embodiments of the present invention, but it is not intended to limit the invention to the solutions shown in the embodiments. It should be noted that, in the following description, "parts" and "%" are based on weight unless otherwise specified.

[0374] <Evaluation Methods>

[0375] [Total transmittance and haze value]

[0376] Peel off one side of the release film from the adhesive sheet with the release film attached, and attach it to a glass slide (Matsunami Glass Industry Co., Ltd., trade name "Shiromazuki No.1", thickness 0.8~1.0 mm, total transmittance 92%, haze value 0.2%). Next, peel off the release film from the other side to prepare a test piece with the adhesive sheet / glass slide layer. Measure the total transmittance and haze value of the obtained test piece using a haze meter (device name "HM-150N", manufactured by Murakami Color Technology Research Institute). For the above measurements, the glass plate with the adhesive sheet attached can be configured such that the adhesive sheet is the light source side.

[0377] [Adhesion to glass]

[0378] The adhesive sheet with the release film was cut into pieces 100 mm long and 20 mm wide. Next, the release film was peeled off from one side of the adhesive sheet, and a PET film (trade name "Lumirror S-10", manufactured by Toray Industries, Ltd., 25 μm thick) was used as a backing. Then, the release film was peeled off from the other side (the testing side), and a 2 kg roller was used to press it onto a glass plate (trade name "Soda-lime Glass") used as a test plate. On a test plate (0050”, manufactured by Matsunami Glass Industry Co., Ltd.), a test piece consisting of a test plate, adhesive sheet, and PET film was prepared. The obtained test piece was subjected to autoclaving (50°C, 0.5MPa, 15 minutes), and then cooled for 30 minutes at 23°C and 50%RH. After cooling, the peel strength when peeling the adhesive sheet (test side) from the test plate was determined using a tensile testing machine (equipment name "Autograph AG-IS", manufactured by Shimadzu Corporation) according to JIS Z 0237, at 23°C and 50%RH, with a tensile speed of 300 mm / min and a peel angle of 180°. This was taken as the glass adhesion force [N / 20mm].

[0379] Note that in the case of an adhesive sheet protected by a peeling film that becomes a peeling surface on both sides, or in the case of a single-sidedly adherable adhesive sheet, the peeling of the peeling film on one side and the backing of the PET film are not required.

[0380] [Peeling force of peeling film]

[0381] An adhesive sheet with a peeling film was cut to a length of 150 mm and a width of 50 mm, and was fixed to a test plate. Using a tensile testing machine (device name "Autograph AG-IS", manufactured by Shimadzu Corporation), the peeling film on the lightly peeled side was peeled from the adhesive sheet under the conditions of an atmospheric temperature of 23°C, an atmospheric humidity of 50% RH, a tensile speed of 300 mm / minute, and a peeling angle of 180°. The maximum value of a 50 mm interval following a 30 mm interval from the start of peeling was taken as the peeling force of the peeling film (lightly peeled side) [N / 50 mm].

[0382] As for the peeling force of the peeling film on the heavily peeled side, the peeling film on the lightly peeled side of the adhesive sheet protected by the peeling film was peeled, and was backed with a PET film (trade name "Lumirror S-10", manufactured by Toray Industries, Inc., thickness 25 μm). The PET film side was fixed to a test plate. Using a tensile testing machine (device name "Autograph AG-IS", manufactured by Shimadzu Corporation), the peeling film on the heavily peeled side was peeled from the adhesive sheet under the conditions of an atmospheric temperature of 23°C, an atmospheric humidity of 50% RH, a tensile speed of 300 mm / minute, and a peeling angle of 180°. The maximum value of a 50 mm interval following a 30 mm interval from the start of peeling was taken as the peeling force of the peeling film (heavily peeled side) [N / 50 mm].

[0383] Note that in the case of an adhesive sheet protected by a peeling film that becomes a peeling surface on both sides, or in the case of a single-sidedly adherable adhesive sheet, the peeling of the peeling film on one side and the backing of the PET film are not required.

[0384] [Arithmetic average roughness (Ra) and maximum height (Rz)]

[0385] The arithmetic average roughness (Ra) and the maximum height (Rz) of the adhesive surface of an adhesive sheet were determined as follows. After the peeling film was peeled from an adhesive sheet with a peeling film at a speed of 300 mm / minute at a peeling angle of 180° under the conditions of the determination of the peeling force of the peeling film described above, the exposed adhesive surface after standing for 30 minutes was determined for the surface shape under an environment of 23°C and 50% RH using a three-dimensional optical profilometer (trade name "NewView 7300", manufactured by ZYGO Corporation).

[0386] The arithmetic surface roughness Ra was calculated from the data obtained by the measurement according to JIS B 0601-2001. In addition, the maximum height (Rz) was calculated as the sum of the height Rp of the highest mountain on the upper side from the average line of the roughness curve and the depth Rv of the deepest valley on the lower side from the average line, for the data (roughness curve) obtained by the above measurement. The measurement conditions were as follows. The measurement of Ra and Rz was performed five times (i.e., N = 5), and the average thereof was used.

[0387] (Measurement conditions)

[0388] Measurement area: 5.62 mm x 4.22 mm

[0389] (Observation: 2.5 times, internal mirror: 0.5 times)

[0390] Analysis mode:

[0391] Remove: Cylinder

[0392] Data Fill: ON (Max: 25)

[0393] Remove Spikes: ON (xRMS: 1)

[0394] Filter: OFF

[0395] [Optical distortion evaluation]

[0396] A commercially available mirror (thickness 2 mm) prepared on a raw plate glass by a silver spraying method was visually confirmed to have no distortion, and a mirror that was confirmed to have no distortion by projecting a reflected image on a screen by the same method as described later was used. After the surface of the above mirror was cleaned of foreign matter and the like with a clean cloth in a clean room, the release film on one side of the adhesive sheet with a release film was peeled off from the adhesive sheet, and the adhesive sheet was attached to the surface of the above mirror with an appropriate tension so as not to mix in foreign matter, bubbles, or distorted stripes. The adhesive sheet was subjected to a degassing treatment (treatment conditions: 50°C, 0.5 MPa, 15 minutes) using a pressurized degassing device (autoclave) in order to remove the effects of minute bubbles. After being left to cool at room temperature for 30 minutes or more, the release film on the other side was peeled off from the adhesive sheet, and an optical distortion evaluation sample (a laminate of an adhesive sheet and a mirror) was prepared. The above evaluation sample was arranged so that the adhesive sheet side thereof faced the point light source side, and the angle with respect to the light from the above point light source was about 45 degrees. A white screen was provided at the front end of the light, and a reflected image was projected thereon. As the point light source, a product of Hamamatsu Photonics K.K. having the trade name "Xenon Lamp C2577" or the equivalent thereof can be used. The point light source, the evaluation sample, and the screen were arranged so that the distance from the evaluation sample to the point light source and the distance from the evaluation sample to the screen were each about 50 cm.

[0397] The above point light source was turned on, and the image reflected by the above sample and projected on the above screen was visually observed, and the presence or absence and the level of optical distortion were evaluated in the following three grades.

[0398] E: No optical distortion was observed.

[0399] A: Slight optical distortion was observed, but the level was practically acceptable.

[0400] P: Obvious optical distortion was observed.

[0401] [Modulus of Elasticity Based on Tensile Test]

[0402] A test piece obtained by cutting an adhesive sheet with a release film (adhesive layer) into a size of 10 mm in width and 150 mm in length was left to stand in an environment of 23°C and 50% RH, and two release films were peeled off to expose the adhesive layer. A tensile test of the test piece was performed using a tensile tester (device name "Autograph AG-IS", manufactured by Shimadzu Corporation) under conditions of a chuck distance of 120 mm and a tensile speed of 50 mm / minute, and a S-S curve was obtained. The modulus of elasticity [MPa] was calculated from the initial slope of the S-S curve (the slope in the elastic deformation region of the S-S curve, specifically, the slope in a range of displacement of less than about 5%).

[0403] Note that the thickness of the test piece used in the tensile test described above can be the same as or different from the thickness of the adhesive sheet (typically, the adhesive layer). For example, in the case where the adhesive sheet is relatively thin, the result obtained by using a test piece prepared so as to have a thickness of 5 μm or more (for example, 5 μm to about 200 μm) in the tensile test described above can be used as the elastic modulus of the adhesive sheet for the purpose of improving workability and the like. In the case of a photocurable adhesive sheet, for example, the thickness of the test piece can be adjusted by appropriately overlapping the adhesive layer before ultraviolet irradiation. Alternatively, a test piece having a thickness that is easy to use in the tensile test can be prepared using the same adhesive composition as that used for forming the adhesive layer of the measurement target, and the result obtained by using this test piece in the tensile test described above can be used as the elastic modulus of the adhesive layer. The tensile test described above can be performed using a test piece having a thickness of 10 μm to about 50 μm (preferably, a thickness of 15 μm to about 25 μm), for example.

[0404] [Impact resistance]

[0405] A shear impact test was performed using a pendulum-type adhesive shear impact tester based on JIS K 6855. As a measurement sample, a sample prepared by cutting an adhesive sheet with a release film into a 10 mm square, peeling off the release film on one side to expose the first adhesive surface of the adhesive sheet, adhering the first adhesive surface to the central portion of a 25 mm square chemical-strengthened glass plate (Corning Incorporated) having a thickness of 1.7 mm, peeling off the release film on the other side to expose the second adhesive surface of the above-described adhesive sheet, adhering the second adhesive surface to the central portion of a 40 mm square stainless steel plate (SUS304BA plate) with a load of 5 N for 10 seconds, followed by autoclave treatment (50°C, 0.5 MPa, 15 minutes), irradiating ultraviolet rays from the glass plate side using a high-pressure mercury lamp at an illuminance of 300 mW / cm 2 , a cumulative light quantity of 3000 mJ / cm 2 , and then, aging for 48 hours at 50°C was used.

[0406] The measurement sample was fixed with the above-described stainless steel plate as the lower side, and the absorbed energy [J] when a hammer was hit against the outer peripheral side surface of the above-described glass plate at a hammer energy of 2.75 J and a hammer speed (impact speed) of 3.5 m / sec in an environment at 23°C and 50% RH was measured, and the impact resistance [J / 10 mm 2 ] was calculated. The measurement was performed three times, and the arithmetic mean value was used.

[0407] Note that in the case of an adhesive sheet protected by a release film of which both surfaces are release surfaces, the measurement can be performed in the same manner as described above, except that the release film is one sheet.

[0408] Note that the adhesive sheet disclosed herein includes an adhesive sheet in a form in which the adhesive layer is photocured after being attached to an adherend, and thus the measurement described above (total light transmittance, haze value, adhesion to glass, arithmetic mean roughness (Ra) and maximum height (Rz) of the adhesive surface, optical distortion evaluation, and elastic modulus based on a tensile test) is performed using a measurement sample after irradiation of ultraviolet rays under conditions of illuminance of 300 mW / cm 2 , cumulative light amount of 3000 mJ / cm 2 , and curing at 50°C for 48 hours, at least for a photocurable adhesive sheet (for example, the adhesive sheet of Example 4 described later with Adhesive C). As for the adhesion to glass, the measurement is performed after the photocurable adhesive sheet (for example, the adhesive sheet of Example 4 described later with Adhesive C) is pressure-bonded to a test plate, and then ultraviolet rays are irradiated under the conditions described above. In addition, the process of irradiating ultraviolet rays described above is preferably performed in a state in which the adhesive sheet (typically, the adhesive layer) is sandwiched between transparent release films, in the case where the release film is transparent.

[0409] As for the illuminance / light amount of the light source, it is desirable to perform the measurement using an industrial UV checker (model "UVR-T2, light receiving part "UD-T36T2", manufactured by TOPCON Corporation") while adjusting the actual distance between the light source and the sample.

[0410] Example 1

[0411] (Preparation of Adhesive Composition)

[0412] After compounding n-butyl acrylate (BA) 57 parts, cyclohexyl acrylate (CHA) 12 parts, 4-hydroxybutyl acrylate (4HBA) 23 parts, hydroxyethyl acrylate (HEA) 8 parts as monomer components, a trade name "Irgacure 651" (manufactured by BASF Corporation) 0.075 parts and a trade name "Irgacure 184" (manufactured by BASF Corporation) 0.075 parts as photopolymerization initiators, the monomer mixture was exposed to ultraviolet rays under a nitrogen atmosphere to perform partial photopolymerization, thereby obtaining a partially polymerized product (acrylic polymer slurry) having a polymerization rate of about 10%. To 100 parts of the obtained acrylic polymer slurry, dipentaerythritol hexaacrylate (trade name "KAYARAD DPHA", manufactured by Nippon Shokubai Co., Ltd.) 0.14 parts and a silane coupling agent (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.) 0.3 parts were added and uniformly mixed, thereby obtaining an acrylic adhesive composition A.

[0413] (Production of Adhesive Sheet)

[0414] As the first release film, a PET release film having a thickness of 75 μm, whose surface S1 to be laminated to the first adhesive surface of the adhesive sheet, i.e., the first adhesive surface side surface S1, was a release surface based on a silicone-based release treatment agent, and whose Ra was 18 nm and Rz was 223 nm, was prepared. As the second release film, a PET release film having a thickness of 100 μm, whose surface S2 to be laminated to the second adhesive surface of the adhesive sheet, i.e., the second adhesive surface side surface S2, was a release surface based on a silicone-based release treatment agent, and whose Ra was 18 nm and Rz was 223 nm, was prepared.

[0415] The acrylic adhesive composition A obtained above was applied on the first adhesive surface side surface S1 of the first release film described above in such a manner that the thickness of the adhesive layer formed after the application became 100 μm, to form an adhesive composition layer, and then the second release film was overlaid on the surface of the adhesive composition layer in such a manner that its second adhesive surface side surface S2 became the adhesive composition layer side. Thereby, the adhesive composition layer was shielded from oxygen. Then, ultraviolet irradiation was performed under conditions of illuminance 5 mW / cm 2 , light amount 2000 mJ / cm 2 , to photocure the adhesive composition layer, to produce a baseless double-coated adhesive sheet composed of only an acrylic adhesive layer (also referred to as adhesive A) and each surface of the acrylic adhesive layer was protected by the first release film and the second release film. Note that the weight average molecular weight (Mw) of the acrylic polymer as the base polymer of the adhesive layer was 2 million.

[0416] Example 2

[0417] As the first release film and the second release film, release films each having surfaces S1, S2 having Ra, Rz shown in Table 1 were used. In addition, the thickness of the adhesive layer was changed to 25 μm. Other than that, the same operations as in Example 1 above were performed to produce the baseless double-coated adhesive sheet of this example.

[0418] Example 3

[0419] The monomer components were changed to 2-ethylhexyl acrylate (2EHA) 68 parts, N-vinyl-2-pyrrolidone (NVP) 15 parts, and HEA 17 parts, and other than that, the same operations as in Example 1 above were performed to prepare an acrylic polymer slurry, and other than using the acrylic polymer slurry obtained, the same operations as in Example 1 above were performed to obtain an acrylic adhesive composition B. Using the acrylic adhesive composition B obtained, the thickness of the adhesive layer (also referred to as adhesive B) was set to 50 μm, and other than that, the same operations as in Example 2 above were performed to produce the baseless double-coated adhesive sheet of this example.

[0420] Example 4

[0421] (Preparation of adhesive composition)

[0422] In a reaction vessel equipped with a cooling tube, a nitrogen gas introduction tube, a thermometer, and a stirring device, BA 60 parts, CHA 6 parts, NVP 18 parts, isostearic acid ester of acrylic acid (iSTA) 1 part, and 4HBA 15 parts as monomer components, α-thioglycerol 0.085 parts as a chain transfer agent, 2,2'-azobisisobutyronitrile (AIBN) 0.2 parts as a thermal polymerization initiator, ethyl acetate as a polymerization solvent so that the monomer components become 45%, and nitrogen gas were put in, and nitrogen gas replacement was performed for about 1 hour while stirring with the flow of nitrogen gas. Then, the reaction vessel was heated to 60°C, and a reaction was performed for 7 hours to obtain an acrylic polymer having a weight average molecular weight (Mw) of 350,000. To a solution of the acrylic polymer (100 parts of solid components) were added 0.1 parts of trimethylolpropane / xylylenediurethane adduct (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D-110N", solid component concentration 75%) as an isocyanate-based crosslinking agent, 0.01 parts of dioctyltin dilaurate (Tokyo Fine Chemical CO., LTD., trade name "EMBILIZER OL-1") as a crosslinking accelerator, 4 parts of acetylacetone as a crosslinking retarder, 0.3 parts of 3-glycidoxypropyltrimethoxysilane (trade name "KBM-403", manufactured by Shin-Etsu Chemical Co., Ltd.) as a silane coupling agent, 8 parts of dipentaerythritol hexaacrylate (manufactured by Shin Nakamura Chemical Industry Co., Ltd., trade name "A-DPH") and 12 parts of tricyclodecane dimethanol diacrylate (manufactured by Shin Nakamura Chemical Industry Co., Ltd., trade name "A-DCP") as photoreactive monomers, and 0.7 parts of 1-hydroxycyclohexyl phenyl ketone (manufactured by IGM Regins Co., Ltd., trade name "Omnirad 184") as a photopolymerization initiator, and uniformly mixed to prepare the adhesive composition C of this example.

[0423] (Production of adhesive sheet)

[0424] As the first and second release films, release films having surfaces S1 and S2 having Ra and Rz shown in Table 1 were used, respectively.

[0425] On the surface S1 of the first adhesive surface side of the first release film described above, the adhesive composition C obtained above was applied in a manner such that the thickness after drying became 20 μm, and was heated and dried at 60°C for 1 minute and at 120°C for 3 minutes under normal pressure, and was further aged at 23°C for 120 hours, to form a photocurable adhesive layer (double-coated adhesive sheet without a substrate). The surface S2 of the second adhesive surface side of the second release film was attached to the surface of the photocurable adhesive layer to protect it. In this way, a double-coated adhesive sheet without a substrate composed of only a photocurable acrylic adhesive layer (also referred to as adhesive C) and the surfaces of the photocurable acrylic adhesive layer being protected by the first and second release films was prepared.

[0426] Example 5

[0427] As the first and second release films, release films having surfaces S1, S2 having Ra, Rz shown in Table 1 were used, respectively. In addition, the thickness of the adhesive layer was changed to 100 μm. Other than this, the same operation as in Example 3 described above was performed to produce the double-coated adhesive sheet without a substrate of this example.

[0428] Examples 6 and 7

[0429] As the first and second release films, release films having surfaces S1, S2 having Ra, Rz shown in Table 1 were used, respectively. In addition, for Example 6, the thickness of the adhesive layer was changed to 25 μm. Other than this, the same operation as in Example 1 described above was performed to produce the double-coated adhesive sheet without a substrate of each example.

[0430] Evaluation

[0431] For the adhesive sheet with a release film of each example, evaluation was performed on the total light transmittance [%], haze value [%], adhesion to glass [N / 20 mm], release force of the release film [N / 50 mm], arithmetic mean roughness (Ra) [nm] of the adhesive surface, maximum height (Rz) [nm], and optical distortion. The results are shown in Table 1. In addition, for the adhesive sheet of Example 4, determination of the elastic modulus based on a tensile test was performed, and for the adhesive sheets of Examples 1 to 4, an impact resistance test was performed. Also shown in Table 1 are the outlines of each example (release surface Ra, Rz of the release film, adhesive type, adhesive sheet thickness [μm], 25°C storage modulus [Pa], gel fraction [%]).

[0432] [Table 1]

[0433]

[0434] As shown in Table 1, in Examples 1 to 5, the maximum height Rz of the adhesive surface side surface of the release film was 400 nm or less, and for the adhesive sheets of these examples, no optical distortion was observed after peeling the release film, or the optical distortion was within a range that was practically acceptable. In addition, the arithmetic mean roughness Ra of the adhesive surface side surface of the release film of these examples was 30 nm or less, and the peeling force of the release film was 1 N / 50 mm or less. On the other hand, in Examples 6 to 7, the maximum height Rz of the adhesive surface side surface of the release film exceeded 400 nm, and unevenness was observed in the optical distortion evaluation. Note that the elastic modulus based on the tensile test of the adhesive sheet of Example 4 was 3.0 MPa or more, and the impact resistance of the adhesive sheets of Examples 1 to 4 was 2.0 J / 10 mm or more 2 above.

[0435] The above detailed specific examples of the present application, but they are merely examples, not limit the scope of the claims. Claims recorded in the scheme, including the above examples of the specific examples of the various transformations, changes into the scheme.

Claims

1. An adhesive sheet with a release film, comprising: an adhesive sheet having an adhesive layer, and a release film laminated on the adhesive surface of the adhesive sheet. in, The total light transmittance of the adhesive sheet is above 85%, and the haze value is below 1%. The gelation rate of the adhesive layer is 84-95% by weight. The maximum height Rz of the adhesive side surface of the release film is less than 400 nm.

2. The adhesive sheet with a release film according to claim 1, wherein, The arithmetic mean roughness Ra of the surface of the peeling film is less than 30 nm.

3. The adhesive sheet with a release film according to claim 1 or 2, wherein, The peeling force of the release film on the adhesive sheet is less than 1N / 50mm.

4. The adhesive sheet with a release film according to claim 1 or 2, wherein, The thickness of the release film is in the range of 50~125μm.

5. The adhesive sheet with a release film according to claim 1 or 2, wherein, The adhesive sheet is an adhesive sheet with one-sided adhesive properties, having the adhesive layer and a supporting substrate laminated on one side of the adhesive layer.

6. The adhesive sheet with a release film according to claim 1 or 2, wherein, The adhesive sheet is a double-sided adhesive sheet with a first adhesive surface and a second adhesive surface. The release film includes a first release film disposed on the first adhesive surface and a second release film disposed on the second adhesive surface. The maximum height Rz1 of the first adhesive side surface S1 of the first release film and the maximum height Rz2 of the second adhesive side surface S2 of the second release film are both below 400 nm.

7. The adhesive sheet with a release film according to claim 1 or 2, wherein, The adhesive sheet is a double-sided adhesive sheet with a first adhesive surface and a second adhesive surface. The release film is a double-sided release film with a first release surface and a second release surface. The maximum height Rz1 of the first peeling surface of the peeling film and the maximum height Rz2 of the second peeling surface of the peeling film are both below 400 nm.

8. The adhesive sheet with a release film according to claim 1 or 2, wherein, The adhesive layer is an acrylic adhesive layer.

9. The adhesive sheet with a release film according to claim 1 or 2, wherein, The energy storage modulus of the adhesive layer at 25°C is 4×10⁻⁶. 4 Pa or above.

10. The adhesive sheet with a release film according to claim 1 or 2, wherein, The thickness of the adhesive sheet is 5~100μm.

11. The adhesive sheet with a release film according to claim 1 or 2, wherein, The elastic modulus of the adhesive sheet, as determined by the following tensile test, is 3.0 MPa or higher. The tensile test is as follows: For the adhesive layer of the adhesive sheet, with an illuminance of 300 mW / cm² 2 Cumulative light intensity 3000 mJ / cm 2 After being irradiated with ultraviolet light and cured at 50°C for 48 hours, the adhesive layer was cut into pieces with a width of 10 mm and a length of 150 mm to make test pieces. The test pieces were subjected to tensile tests using a tensile testing machine at 23°C and 50%RH with a chuck spacing of 120 mm and a tensile speed of 50 mm / min. The stress-displacement curve was obtained, and the elastic modulus [MPa] was calculated from its initial slope.

12. The adhesive sheet with a release film according to claim 1 or 2, wherein, The adhesive layer contains a polymer (A) and a photoreactive monomer (B).

13. The adhesive sheet with a release film according to claim 12, wherein, The photoreactive monomer (B) comprises a compound B1 having an intramolecular ring structure and two or more olefinic unsaturated groups, wherein the molecular weight of compound B1 relative to each of the olefinic unsaturated groups is 100 g / mol or more.

14. The adhesive sheet with a release film according to claim 1 or 2, used to fix a component having an image display surface, a decorative surface or a colored surface to a transparent component.

15. A roll of adhesive sheet with a release film, which is formed by winding the adhesive sheet with a release film according to any one of claims 1 to 14.

Images