WO2025234349A1 - Adhesive sheet - Google Patents

Abstract

Provided is an adhesive sheet that hardly exhibits a folded trace in a bent portion when the adhesive sheet is stuck to an adherend and is bent.　An adhesive sheet 10 is provided with at least an adhesive layer 1. The adhesive layer 1 has a first region 11 and a second region 12 each having one linear shape in the same plane. The first region 11 and the second region 12 are parallel to each other, and the first region 11 and the second region 12 have different physical properties. The first region 11 and the second region 12 preferably have different hardness. Each of the first region 11 and the second region 12 may have one straight-line shape.

Description

adhesive sheet

The present invention relates to an adhesive sheet.

Among optical devices such as displays, thin, flexible displays, typified by OLEDs, are constructed by laminating multiple optical films and thin-layer devices. Furthermore, devices that require flexibility, such as pressure-sensitive sensors, are constructed by laminating a pressure-sensitive member and a substrate (Patent Document 1). Liquid curing resins, pressure-sensitive adhesives, and adhesives are selected as interlayer fillers in these laminates, with pressure-sensitive adhesives and adhesives (such as pressure-sensitive adhesives) being preferred from the standpoints of improving workability, preventing warping due to curing shrinkage, and improving flexibility through stress dispersion.

The above-mentioned adhesives, particularly in flexible materials, have the function of dispersing and mitigating stresses generated by bending and folding, and this function is said to be more efficiently exerted the more flexible the adhesive is (Patent Document 2), so flexible adhesives are used.

JP 2012-159463 A Japanese Patent Application Laid-Open No. 2020-109177

However, when laminates are made by bonding adherends together using an adhesive sheet with a flexible adhesive layer, the adhesive layer is unable to withstand the bending stress of the adherends when the laminate is bent, causing the folded portion of the laminate to become indented and leaving crazes.

The present invention is designed to solve these problems, and its purpose is to provide an adhesive sheet that, when attached to an adherend and folded, is less likely to leave creases at the folded portion.

As a result of extensive efforts to solve the above problems, the inventors discovered that with a specific pressure-sensitive adhesive sheet, when attached to an adherend and folded, creases are less likely to form at the folded portion. The present invention was completed based on these findings.

That is, the present invention provides a pressure-sensitive adhesive layer having, in the same plane, a first region which is a single linear region and a second region which is a single linear region parallel to the first region,
The pressure-sensitive adhesive sheet has different physical properties between the first region and the second region.

The above physical property is preferably hardness.

The above hardness is preferably one or more selected from the group consisting of tensile strength, modulus of elasticity, Young's modulus, elongation at break, stress at break, surface hardness, swelling degree, gel fraction, hardness measured by nanoindentation, and residual stress.

It is preferable that the first region and the second region each be a single straight line.

In the pressure-sensitive adhesive layer, the first regions and the second regions are preferably arranged alternately in one direction of the pressure-sensitive adhesive layer.

It is preferable that the first region and the second region extend from one end to the other end in a direction perpendicular to the thickness direction of the adhesive layer.

The pressure-sensitive adhesive sheet may be used by being attached to a foldable adherend, the first region being included in an area corresponding to the fold of the adherend, the second region being adjacent to both sides of the first region, and the hardness of the first region being greater than the hardness of the second region.

the pressure-sensitive adhesive sheet has a hardness of the first region greater than a hardness of the second region,
The pressure-sensitive adhesive sheet may be one in which the first region and the second region are alternately adjacent to each other in one direction of the pressure-sensitive adhesive layer, and the first region is located within a range of ±1 mm from the center in the one direction.

The above-mentioned adhesive sheet is preferably used by adhering it to an optical component.

The above-mentioned pressure-sensitive adhesive sheet is preferably used by adhering it to a foldable adherend.

When the pressure-sensitive adhesive sheet of the present invention is attached to an adherend and folded, creases are unlikely to form at the folded portion.

1 shows a schematic cross-sectional view of a pressure-sensitive adhesive sheet according to one embodiment of the present invention. 1 shows a plan view of a pressure-sensitive adhesive sheet according to one embodiment of the present invention. 3 is a cross-sectional view showing the pressure-sensitive adhesive sheet shown in FIG. 2 in a folded state. FIG. 2 is a plan view of a pressure-sensitive adhesive sheet according to another embodiment of the present invention. FIG. 5 is a cross-sectional view showing the adhesive sheet shown in FIG. 4 in a folded state. FIG. 2 is a plan view showing an embodiment of a pressure-sensitive adhesive sheet in which the first region and the second region are curved. FIG. 2 shows a plan view of a pressure-sensitive adhesive composition in an example. 1 is a graph showing nanoindentation hardness measured in the vicinity of a first region and a second region in an example.

[Adhesive sheet]
In this specification, "adhesion" refers to the property of two surfaces adhering to each other in response to external pressure (e.g., minute pressure) based on the cohesive force of the chemical structure of the composition, and allowing separation as needed. In contrast, "adhesion" refers to the property of two surfaces being firmly joined together by a chemical reaction (curing) of the composition to produce a cured product, without the intention of separation.

In addition, in this specification, the form of the "adhesive" is not particularly limited, and it may be liquid at room temperature (for example, a solid (paste) with fluidity, an adhesive composition, etc.), or it may be solid at room temperature. In addition, the form of the "adhesive" is not particularly limited, and it may be in sheet form. In this specification, an "adhesive layer" is a sheet-like (layer-like) adhesive layer with no fluidity.

The pressure-sensitive adhesive sheet of the present invention comprises at least a pressure-sensitive adhesive layer having, in the same plane, a first region that is a single line and a second region that is parallel to the first region and is also a single line. The first region and the second region have different physical properties. In this specification, the pressure-sensitive adhesive layer may be referred to as the "pressure-sensitive adhesive layer of the present invention." Furthermore, "a single line" refers to a line that has no branch points.

The pressure-sensitive adhesive sheet of the present invention may be a so-called "substrate-less type" pressure-sensitive adhesive sheet that does not have a substrate (substrate layer), or may be a type of pressure-sensitive adhesive sheet that has a substrate. In this specification, a "substrate-less type" pressure-sensitive adhesive sheet may be referred to as a "substrate-less pressure-sensitive adhesive sheet," and a type of pressure-sensitive adhesive sheet that has a substrate may be referred to as a "substrate-attached pressure-sensitive adhesive sheet." Examples of the substrate-less pressure-sensitive adhesive sheet include a double-sided pressure-sensitive adhesive sheet consisting only of the pressure-sensitive adhesive layer of the present invention, and a double-sided pressure-sensitive adhesive sheet consisting of the pressure-sensitive adhesive layer of the present invention and another pressure-sensitive adhesive layer (a pressure-sensitive adhesive layer other than the pressure-sensitive adhesive layer of the present invention). Examples of the substrate-attached pressure-sensitive adhesive sheet include a single-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer of the present invention on one side of the substrate, a double-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer of the present invention on both sides of the substrate, and a double-sided pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer of the present invention on one side of the substrate and another pressure-sensitive adhesive layer on the other side. The "substrate (substrate layer)" refers to a support, and is the part that is attached to the adherend together with the pressure-sensitive adhesive layer when the pressure-sensitive adhesive sheet of the present invention is used (attached) to an adherend. The release liner that is peeled off when the adhesive sheet is used (applied) is not included in the above substrate.

The pressure-sensitive adhesive sheet of the present invention will be described below with reference to the drawings. However, the pressure-sensitive adhesive sheet of the present invention is not limited to the embodiments shown in the drawings.

Figure 1 is a cross-sectional view showing a pressure-sensitive adhesive sheet according to one embodiment of the present invention. The pressure-sensitive adhesive layer 1 shown in Figure 1 is laminated onto the release-treated surface of a release liner 2, forming a pressure-sensitive adhesive sheet 10 with a release liner.

<Adhesive Layer>
(First embodiment)
Fig. 2 shows a plan view of a pressure-sensitive adhesive sheet (first embodiment) according to one embodiment of the present invention. The pressure-sensitive adhesive layer 1 shown in Fig. 2 has a single linear first region 11 and a single linear second region 12 extending in a direction (first direction D1) perpendicular to the thickness direction of the pressure-sensitive adhesive layer 1. Furthermore, the pressure-sensitive adhesive layer 1 has, in the same plane, the first region 11, the second region 12, the first region 11, the second region 12, and the first region 11, in this order, extending in a second direction D2 perpendicular to the first direction D1. The first region 11 and the second region 12 are alternately formed in one direction (second direction D2) from the first edge E1 of the pressure-sensitive adhesive layer 1 toward the second edge E2 opposite the first edge E1. The first region 11 and the second region 12 are each continuously formed so as to extend from one end side (third edge E3) of the pressure-sensitive adhesive layer 1 to the other end side (fourth edge E4 opposite the third edge E3). In FIG. 2, the boundary between the first region 11 and the second region 12 is depicted by a solid line, but in reality, the boundary does not need to be observed visually.

The three first regions 11 and two second regions 12 extend in the first direction D1 and are parallel to each other. Note that in Figure 2, all of the first regions 11 and second regions 12 are parallel to each other; however, in the pressure-sensitive adhesive layer of the present invention, since it can be folded and used, it is sufficient that at least one first region 11 and at least one second region 12 are parallel to each other.

The first region 11 and the second region 12 have different physical properties. For example, the hardness of the first region 11 is greater than the hardness of the second region 12. In other words, the first region 11 may be a hard portion that is relatively harder (than the second region 12), and the second region 12 may be a soft portion that is relatively softer (than the first region 11).

The first region 11 and the second region 12 may have the same or different widths. Also, in Figure 2, the widths of the two second regions 12 are the same, but they may be different. Also, in Figure 2, the widths of the two first regions 11 located at both ends are the same, and the width of the first region 11 located in the middle is shorter than the widths of the other two first regions 11, but it may be longer or the same. The widths of all the first regions and all the second regions may be the same or different.

The first region 11 is located in the center of one direction (first direction D1) of the adhesive layer 1, and two second regions 12 are adjacent to both sides of the central first region 11.

In the adhesive layer 1 shown in Figure 2, the total area of the first regions 11 is larger than the total area of the second regions 12. Also, in the adhesive layer 1 shown in Figure 2, the total line width length of the first regions 11 is longer than the total line width length of the second regions 12. When the hardness of the first regions 11 is greater than the hardness of the second regions 12, the strength of the adhesive layer and adhesive sheet in such a configuration is increased. Note that the total area of the first regions 11 may be smaller than the total area of the second regions 12, and the total line width length of the first regions 11 may be shorter than the total line width length of the second regions 12.

An adhesive sheet having an adhesive layer such as that shown in Figure 2 has a first region and a second region with different physical properties, so that when bending stress is applied to one of the first region and the second region, the other can absorb the bending stress, thereby preventing the formation of creases when folded.

Figure 3 shows an example of the folded state of the adhesive sheet shown in Figure 2. When the adhesive sheet 10 made of the adhesive layer 1 shown in Figure 2 is folded in the middle, as shown in Figure 3, the first region 11, which is a hard region, is located in the middle of the folded portion B, and the second region 12, which is a soft region, is located on both sides of it, and the folded portion B includes the second region 12/first region 11/second region 12. When folded in this way, when bending stress is applied to the first region 11, the second region 12 can relieve the bending stress, making it less likely that a fold mark will be left when folded. It is also preferable that the folded portion B includes both the first region 11 and the second region 12.

Second Embodiment
Figure 4 shows a plan view of a pressure-sensitive adhesive sheet according to another embodiment of the present invention (second embodiment). The pressure-sensitive adhesive layer 1 shown in Figure 4 has a single linear first region 11 and a single linear second region 12 extending in a first direction D1. The pressure-sensitive adhesive layer 1 shown in Figure 4 is similar to the pressure-sensitive adhesive layer 1 shown in Figure 2 except that the number and widths of the first regions 11 and second regions 12 are different. In the pressure-sensitive adhesive layer 1 shown in Figure 4, the first regions 11 and second regions 12 are formed in a striped pattern.

As shown in Figure 3, an adhesive sheet having an adhesive layer in which first and second regions are adjacent to each other in one direction and formed in alternating stripes has alternating physical properties, so when stress is applied to one region, the stress is easily distributed to the other adjacent region, resulting in superior strength and impact resistance overall for the adhesive sheet and for the adherend to which the adhesive sheet is bonded.

The widths of the first region 11 and the second region 12 (the width of one region) are not particularly limited, but can each be selected, for example, within the range of 0.001 to 50 mm. Furthermore, the ratio of the width of the first region 11 (the width of one region) to the width of the second region 12 (the width of one region) [first region/second region] is not particularly limited, but is, for example, 0.01 to 100.

The boundary between the first region 11 and the second region 12 may or may not be clearly defined. The area near the boundary between the first region 11 and the second region 12 may be a boundary region where the physical properties change gradually. The boundary region has a gradient of physical properties, and gradually changes from the physical properties of the first region 11 to the physical properties of the second region 12 along the second direction D2 from the center of the first region 11 to the center of the second region 12. Therefore, the boundary region is the region from the point where the gradient of physical properties starts to the point where the gradient ends. When the boundary region is present, the physical properties of the first region 11 and the physical properties of the second region 12 are the physical properties of the portions other than the boundary region (for example, the center portion in the second direction D2).

In Figures 2 and 4, the hardness of the first region 11 is greater than the hardness of the second region 12. Furthermore, in the adhesive layer 1, the first region 11 and the second region 12 are positioned adjacent to each other alternately in one direction (second direction D2) of the adhesive layer 1. In Figure 2, the center of the second direction D2 is the first region 11. Furthermore, in Figure 4, the first region is located within a range of ±1 mm from the center of the second direction D2. With this configuration, when the bending portion is near the center of the second direction D2, the first region 11 will be subjected to the greatest bending stress when folded. However, the shape of the adhesive layer is more easily maintained, and the bending stress can be alleviated in the adjacent second region 12, thereby particularly suppressing the occurrence of creases when folded.

5 shows an example of the folded state of the adhesive sheet shown in FIG. 4. When the adhesive sheet 10 made of the adhesive layer 1 shown in FIG. 4 is folded at the center, as shown in FIG. 5, the first region 11, which is a hard portion, and the second regions 12 on either side of it are located near the center of the folded portion B (within a range of ±1 mm from the center), and the folded portion B includes the second region 12/first region 11/second region 12/first region 11/second region 12/first region 11/second region 12. The folded portion B also includes both the first region 11 and the second region 12. In the adhesive sheet 10 shown in FIG. 4, the first region 11 and the second region 12 are both narrower than those in the adhesive sheet shown in FIG. 2. Therefore, when folded as shown in FIG. 5, even if the first region 11 is not located at the center in the second direction D2, when bending stress is applied to the first region 11, the second region 12 can relieve the bending stress, and fold marks are less likely to occur when folded. The pressure-sensitive adhesive sheet shown in Figure 4 can also be rolled by folding at least a portion of it. Therefore, the pressure-sensitive adhesive layer 1 shown in Figure 4 can be rolled up to fit the adherend, even when it is attached to a rollable adherend so that the position corresponding to the center of the folded portion is the region including the second region 12.

In addition, if the hardness of the first region 11 is greater than the hardness of the second region 12, the center of the pressure-sensitive adhesive layer 1 in the second direction D2 does not have to be the first region 11. As long as the first region 11 is included in a region corresponding to the folding portion of a foldable adherend, the occurrence of fold marks when folding can be particularly suppressed.

In Figures 2 and 4, the first region 11 and the second region 12 are both formed in a straight line, but the first region 11 and the second region 12 may also be linear, with at least a portion of the line curved, within the range in which the adhesive sheet can be bent. Furthermore, the first region 11 and the second region 12 may have a line width that varies at least partially along the length, within the range in which the adhesive layer can be bent. The maximum value of the radius of curvature of the curve is not particularly limited, but is, for example, R1000 mm or less (e.g., R greater than 0 mm and R1000 mm or less).

Furthermore, when the first region 11 and/or the second region 12 includes a curve, it is preferable that the first region 11 and/or the second region 12 have a shape that allows a single straight line to be drawn within that region without contacting adjacent regions. For example, in the pressure-sensitive adhesive layer 1 shown in Figure 6, the first region 11 and the second region 12 are formed in a curved shape, and a straight line L1 can be drawn within the first region 11 without contacting adjacent second regions.

2 and 4, both the first region 11 and the second region 12 extend continuously from the third edge E3 to the fourth edge E4. However, at least one of the first region 11 and the second region 12 may extend discontinuously. For example, at least one of the first region 11 and the second region 12 may be represented by a dashed line. The length and/or spacing of each region in the dashed lines may be the same or different. The spacing may be regular or irregular. At least one of the first region 11 and the second region 12 may not extend from the third edge E3 to the fourth edge E4. For example, it may extend from a region away from the third edge E3 to the fourth edge E4, or it may extend from the third edge E3 in the direction of the fourth edge E4 but not reach the fourth edge E4, or it may extend from a region away from the third edge E3 in the direction of the fourth edge E4 but not reach the fourth edge E4.

The respective numbers and total numbers of first regions 11 and second regions 12 in the second direction D2 are not particularly limited. For example, when first regions 11 and second regions 12 are alternately formed adjacent to one another in the second direction D2, the greater the total number, the stronger the adhesive layer and adhesive sheet will tend to be. Furthermore, even when the adherend has many folded portions, the frequency corresponding to the first regions 11 will be higher, making it less likely that creases will occur when folded. Note that in this specification, when first regions 11 or second regions 12 are indicated by dashed lines, a group of regions extending from the third edge E3 toward the fourth edge E4 will be considered one region.

The adhesive layer 1 shown in Figures 2 and 4 is symmetrical in one direction (first direction D1 and/or second direction D2). For example, in Figures 2 and 4, the first region 11 and the second region 12 are positioned symmetrically in one direction (second direction D2). However, the adhesive layer may also be asymmetrical in one direction.

The adhesive layer 1 shown in Figures 2 and 4 has first regions 11 at both ends in one direction (second direction D2). If the hardness of the first regions 11 is greater than the hardness of the second regions 12, the strength of the adhesive layer and adhesive sheet will be higher in this configuration. Note that both ends in one direction (second direction D2) do not have to be first regions 11.

In the adhesive layer 1, the first region 11 and the second region 12 may each extend over the entire thickness of the adhesive layer, or may only cover a portion including the surface. The thicknesses of the first region 11 and the second region 12 in the adhesive layer 1 are not particularly limited, but can each be selected, for example, from within the range of 0.1 to 300 μm. Furthermore, the ratio of the thickness (average thickness) of the first region 11 to the thickness (average thickness) of the second region 12 [first region/second region] is not particularly limited, but is, for example, 0.1 to 10. The thicknesses of all the first regions and all the second regions may be the same or different.

The first region 11 and the second region 12 may have different optical properties. In particular, when the adhesive sheet 10 is used to attach to an optical component in an image display device, the adhesive sheet located on the display side is required to have high transparency, and in this case, it is preferable that the first region 11 and the second region 12 have high transparency. On the other hand, when the adhesive sheet 10 is used to attach to an optical component in an image display device and is used on the back side of the image display device, the transparency of the first region 11 and the second region 12 may be low.

The adhesive layer 1 may have regions other than the first region 11 and the second region 12. These regions can be arranged in any location and shape as long as the adhesive sheet can be folded. In Figures 2 and 4, the first region 11 and the second region 12 are alternately formed in the adhesive layer 1, and in particular, the first region 11 and the second region 12 are alternately formed adjacent to each other. Specifically, the adhesive layer 1 has a structure of [first region 11/second region 12/.../first region 11] along one direction (second direction D2). Here, if the adhesive layer has a third region as another region with physical properties different from both the first region 11 and the second region 12, the adhesive layer may have a structure of [first region/second region/third region/first region/second region/third region/.../first region].

The physical properties in which the first region 11 and the second region 12 differ include hardness and optical properties. Examples of hardness include tensile strength, modulus of elasticity, Young's modulus, elongation at break, stress at break, surface hardness, swelling, gel fraction, hardness measured by nanoindentation, and residual stress. Using the nanoindentation method, measurements can be performed, for example, on the surface of the adhesive layer 1 or on the exposed surface of the adhesive layer 1 in a cross section. The hardness measured using the nanoindentation method is determined by continuously measuring the load and indentation depth applied to the indenter when the indenter is pressed into the target surface, both during loading and unloading, and then deriving the load-indentation depth curve. The hardness can be adjusted using known or conventional methods. Specifically, the hardness of each region of the adhesive layer can be controlled by adjusting the amount of curing agent, crosslinking agent, crosslinkable compound such as a polyfunctional monomer, or polymerization initiator used in preparing the resin that constitutes the adhesive layer 1. The different physical properties may be of only one type, or of two or more types.

The tensile strength, Young's modulus, elongation at break, and stress at break can be measured specifically by the following measurement methods.
<Methods for measuring tensile strength, Young's modulus, elongation at break, and stress at break>
A cylindrical sample of the pressure-sensitive adhesive layer cut out from the region to be measured is rolled to 30 mm x 1 mm in diameter, chucked at the top and bottom 5 mm apart with a chuck distance of 10 mm, and pulled at a rate of 50 mm/min. The tensile strength is calculated from the maximum stress, the initial tensile modulus (Young's modulus) from the slope at 50% elongation, and the elongation at break and stress at break are calculated from the elongation and stress at break, respectively, from the stress-strain curve measured using a tensile tester (AUTOGRAPH AGS-X, manufactured by Shimadzu Corporation).

Examples of the elastic modulus include the elastic modulus at -20°C, the elastic modulus at room temperature (25°C), and the elastic modulus at 80°C. Examples of the elastic modulus include the storage elastic modulus and the loss elastic modulus.

The storage modulus of the first region 11 and the second region 12 at -20°C is not particularly limited, but can be selected, for example, from within the range of 10 kPa to 100 MPa.

The storage modulus at 25°C of the first region 11 and the second region 12 is not particularly limited, but can be selected, for example, from within the range of 1 kPa to 100 MPa.

The storage modulus at 80°C of the first region 11 and the second region 12 is not particularly limited, but can be selected, for example, from within the range of 10 kPa to 10 MPa.

The storage modulus of the pressure-sensitive adhesive layer is a value measured by dynamic viscoelasticity. The storage modulus can be controlled by the type of base polymer of the pressure-sensitive adhesive that makes up the pressure-sensitive adhesive layer, the monomer composition, weight-average molecular weight, the amount of crosslinking agent used (added amount), and the type and content of other additives. Specifically, the elastic modulus (storage modulus) can be measured by the following measurement method.

<Method for measuring elastic modulus>
A plurality of pressure-sensitive adhesive layer pieces cut from the region to be measured are laminated together to prepare a pressure-sensitive adhesive sheet approximately 1 mm thick, which is then punched out to obtain cylindrical pellets (9 mm in diameter) as measurement samples. The measurement samples are then fixed to a parallel plate jig with a diameter of 8 mm using a dynamic viscoelasticity measuring device (trade name "ARES-G2", manufactured by TA Instruments), and subjected to dynamic viscoelasticity measurement. In this measurement, the measurement mode is shear mode, the measurement temperature range is -70°C to 150°C, the heating rate is 5°C/min, and the frequency is 1 Hz. The storage moduli at -20°C, 25°C, and 80°C are then read from the measurement results.

The surface hardness is an AFM hardness. Specifically, the surface hardness can be measured by the following measurement method.
<Surface hardness>
The pressure-sensitive adhesive layer in the area to be measured is cut into a piece approximately 1 cm square, which is fixed to a support (a slide glass manufactured by Matsunami Glass Industry Co., Ltd.) to prepare a sample for AFM measurement. AFM measurement is performed under the following conditions to obtain a load-displacement curve.
AFM measurement conditions: Asylum Research Jupiter XR manufactured by Oxford Instruments
Cantilever used: AC240TS (Si, spring constant equivalent to 1.7 N/m)
Measurement mode: AFM force curve mapping Measurement temperature: room temperature Scan rate: 2 Hz
Measurement range: The boundary area spanning the first and second areas was set as the center of the measurement, and an 80 μm x 20 μm range was scanned (128 x 16 pixels).
Hardness: The average value of the elastic modulus in a 10 μm×20 μm area is calculated and used for each of the first and second regions.

The gel fraction (proportion of solvent-insoluble components) of the first region 11 and the second region 12 is not particularly limited, but can be selected from within the range of, for example, 40% or more (e.g., 40 to 100%).

The swelling degree of the first region 11 and the second region 12 is not particularly limited, but can be selected, for example, from within the range of 1 to 20 times.

The above gel fraction and swelling degree are specifically values calculated, for example, by the "Method for measuring gel fraction and swelling degree" below.

<Method for measuring gel fraction and swelling degree>
Approximately 0.1 g was collected from the pressure-sensitive adhesive layer in the area to be measured, wrapped in a porous tetrafluoroethylene sheet (trade name "NTF1122", manufactured by Nitto Denko Corporation) with an average pore size of 0.2 μm, and then tied with kite string. The weight at this time was measured and this weight was designated as the pre-immersion weight X. The pre-immersion weight was the total weight of the pressure-sensitive adhesive layer (the pressure-sensitive adhesive layer collected above), the tetrafluoroethylene sheet, and the kite string. The total weight of the tetrafluoroethylene sheet and the kite string was also measured, and this weight was designated as the wrapping weight Y. Next, the pressure-sensitive adhesive layer wrapped in the tetrafluoroethylene sheet and tied with kite string (referred to as the "sample") was placed in a 50 ml container filled with ethyl acetate and allowed to stand at 23° C. for 7 days. Thereafter, the sample (after ethyl acetate treatment) was removed from the container and transferred to an aluminum cup, and the weight of the sample at this time was designated as Z0. Then, the sample is dried in a dryer at 130° C. for 2 hours to remove ethyl acetate, and then the weight of the sample is measured, and this weight is defined as the weight Z after immersion.
Then, the gel fraction is calculated using the following formula.
Gel fraction [% (wt%)] = (Z-Y) / (X-Y) × 100
Swelling ratio [times] = (Z0-Y)/(Z-Y)

The above gel fraction and swelling degree can be controlled, for example, by the type of base polymer and monomer composition of the adhesive constituting the adhesive layer, the weight average molecular weight, the type and amount (addition amount) of crosslinking agent, etc.

The optical properties mentioned above include transparency, visible light transmittance, total light transmittance, haze value, refractive index, etc.

The transmittance (total light transmittance) of the first region 11 and the second region 12 is not particularly limited, but can be selected, for example, from within the range of 1 to 100%. The total light transmittance is a value measured in accordance with JIS K7361-1.

The haze values of the first region 11 and the second region 12 are not particularly limited, but can each be selected, for example, from a range of 99% or less (e.g., 0 to 99%). The "haze value" refers to the ratio of diffuse transmitted light to total transmitted light when visible light is irradiated onto the object to be measured, and is also called the cloudiness value. The haze value can be expressed by the following formula:
Th(%)=Td/Tt×100
In the above formula, Th is the haze value (%), Td is the scattered light transmittance, and Tt is the total light transmittance. The haze value can be adjusted, for example, by selecting the composition, thickness, etc. of the pressure-sensitive adhesive layer.

The refractive indexes of the first region 11 and the second region 12 are not particularly limited, but can each be selected, for example, from within the range of 1.1 to 1.9.

In addition, when measuring the various physical properties described in this specification, if it is difficult to cut out an adhesive layer of a predetermined size from the area to be measured, an adhesive layer of the same composition as the area to be measured may be prepared, and an adhesive layer of the predetermined size may be cut out from this adhesive layer to prepare a measurement sample.

(Method for producing pressure-sensitive adhesive layer)
The pressure-sensitive adhesive layer having the first region and the second region can be produced by a known or conventional method. Examples of the method for producing the pressure-sensitive adhesive layer include methods 1 to 4. The first to fourth methods may be used alone or in combination of two or more.

The first method is to use adhesive compositions with different compositions for forming the first region and the second region. Examples of different adhesive compositions include compositions that differ in the type of base polymer of the adhesive that makes up the adhesive layer, the monomer composition of the base polymer, the weight-average molecular weight of the base polymer, the type of crosslinking agent, the amount of crosslinking agent used (added amount), and the type and content of other additives. For example, if the amount of crosslinking agent used is different, the region using a larger amount of crosslinking agent will be a relatively hard region, and the region using a smaller amount of crosslinking agent will be a relatively soft region.

The base polymer constituting the first region and the second region may be any known or commonly used polymer, such as an acrylic polymer, a urethane acrylate resin, a urethane resin, a rubber resin, an epoxy resin, an epoxy acrylate resin, an oxetane resin, a silicone resin, a silicone acrylic resin, a polyester resin, a polyether resin (such as polyvinyl ether), a polyamide resin, a fluorine-based resin, a vinyl acetate/vinyl chloride copolymer, or a polyolefin.

Examples of the crosslinking agent include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, melamine-based crosslinking agents, peroxide-based crosslinking agents, urea-based crosslinking agents, metal alkoxide-based crosslinking agents, metal chelate-based crosslinking agents, metal salt-based crosslinking agents, carbodiimide-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, amine-based crosslinking agents, silicone-based crosslinking agents, silane-based crosslinking agents, and polyfunctional monomers such as polyfunctional (meth)acrylates. In this specification, the term "crosslinking agent" refers to a compound capable of crosslinking resins, and may also be referred to as a "curing agent."

The other additives mentioned above include, for example, crosslinking accelerators, tackifying resins (rosin derivatives, polyterpene resins, petroleum resins, oil-soluble phenols, etc.), oligomers, antioxidants, fillers (metal powders, organic fillers, inorganic fillers, etc.), antioxidants, plasticizers, softeners, surfactants, antistatic agents, surface lubricants, leveling agents, light stabilizers, UV absorbers, polymerization inhibitors, granular materials, foil-like materials, and release adjusters.

In the first method, for example, first, a pressure-sensitive adhesive composition that forms the first region and a pressure-sensitive adhesive composition that forms the second region are applied to the release-treated surface of the same release liner or substrate, respectively. The application of the pressure-sensitive adhesive composition that forms the first region and the pressure-sensitive adhesive composition that forms the second region may be performed simultaneously or sequentially. After the pressure-sensitive adhesive composition is applied to the release-treated surface of the release liner or the substrate to form a pressure-sensitive adhesive composition layer, the pressure-sensitive adhesive composition layer is solidified by volatilizing and removing the solvent through heating or by polymerization through active energy ray irradiation to form a pressure-sensitive adhesive layer, thereby producing a pressure-sensitive adhesive layer having a first region and a second region. Furthermore, if necessary, heating, drying, etc. may be performed in addition to the active energy ray irradiation.

The second method is to use the same adhesive composition as the adhesive composition forming the first region and the adhesive composition forming the second region, add a modifier so that the blending amount differs between the region to be the first region and the region to be the second region, and then form an adhesive layer. In this case, an active energy ray-polymerizable adhesive composition can be used as the adhesive composition.

In the second method, for example, first, the adhesive composition that will form the adhesive layer is applied to the release-treated surface of a release liner or to the substrate. After the adhesive composition is applied to the release-treated surface of the release liner or to the substrate to form the adhesive composition layer, a modifier is added to the region that will become the first region and/or the region that will become the second region. The addition can be carried out by application. The modifier may be added to only one of the region that will become the first region or the region that will become the second region, or it may be added to both. If added to both, the amounts added should be different. The modifier added may be the modifier itself, or it may be a solution or dispersion in which it is dissolved or dispersed in a solvent.

The modifiers can be any additive commonly used in the field of adhesives. Examples include polymerization initiators, crosslinking agents, UV absorbers, rust inhibitors, antistatic agents, crosslinking accelerators, silane coupling agents, tackifying resins, antioxidants, colorants such as dyes, antioxidants, chain transfer agents, plasticizers, softeners, surfactants, and fillers. Regions containing a high amount of crosslinking agent will have a higher crosslink density of the base polymer when the adhesive layer is formed, resulting in relatively hard regions. Regions containing a high amount of plasticizer will be relatively soft regions. After the modifier is added, the adhesive composition layer can be solidified by volatilizing and removing the solvent through heating or by polymerization through active energy ray irradiation to form an adhesive layer having first and second regions.

The third method is to use the same adhesive composition to form the first region and the second region, but to differentiate the degrees of polymerization. In this case, an active energy ray-polymerizable adhesive composition can be used as the adhesive composition.

In the third method, for example, first, the adhesive composition that will form the adhesive layer is applied to the release-treated surface of a release liner or to a substrate. After the adhesive composition is applied to the release-treated surface of a release liner or to a substrate to form the adhesive composition layer, a photomask is placed over a portion of the adhesive composition layer, and the adhesive composition layer is irradiated with active energy rays. If necessary, heating, drying, etc. may be performed in addition to the active energy ray irradiation. In this way, the adhesive layer is formed by solidifying the adhesive composition layer through polymerization via active energy ray irradiation. The areas covered with the photomask are not irradiated with active energy rays or the amount of active energy ray irradiation is low, resulting in a relatively low degree of polymerization in those areas. On the other hand, the areas not covered with the photomask are irradiated with a high amount of active energy ray irradiation, resulting in a relatively high degree of polymerization in those areas. The two areas formed in this way have different physical properties, such as hardness, and can be referred to as the first region and the second region.

In a third method, the entire pressure-sensitive adhesive composition layer may be covered with a photomask having regions with different levels of transmittance for active energy rays, and then the pressure-sensitive adhesive composition layer may be irradiated with active energy rays. In this way, a pressure-sensitive adhesive layer having first and second regions with different levels of exposure to active energy rays can be produced.

The fourth method is to form an adhesive layer using the same adhesive composition as the adhesive composition forming the first region and the adhesive composition forming the second region, and then impregnate the adhesive layer with the modifier so that the blending amount differs between the region to be designated as the first region and the region to be designated as the second region. In this case, an active energy ray-polymerizable adhesive composition can be used as the adhesive composition.

In the fourth method, for example, first, the adhesive composition that will form the adhesive layer is applied to the release-treated surface of a release liner or to a substrate. After applying the adhesive composition to the release-treated surface of a release liner or to a substrate to form an adhesive composition layer, the adhesive composition layer is solidified by volatilizing and removing the solvent through heating or by polymerization through exposure to active energy rays, thereby forming an adhesive layer. Then, the region to be the first region and/or the region to be the second region is impregnated with a modifier. In this way, an adhesive layer having a first region and a second region can be produced.

Impregnation can be carried out by application. The modifier may be impregnated into only one of the regions to be designated as the first region and the region to be designated as the second region, or both. If both are impregnated, the amounts added should be different. The modifier to be impregnated may be the modifier itself, or it may be a solution or dispersion in which it is dissolved or dispersed in a solvent.

(Base material)
When the pressure-sensitive adhesive sheet of the present invention is a substrate-attached pressure-sensitive adhesive sheet or the like, the substrate is not particularly limited, and examples thereof include various optical films such as plastic films, anti-reflection (AR) films, anti-glare (AG) films, polarizing plates, and retardation plates. Examples of the substrate include porous materials such as paper, cloth, and nonwoven fabrics, nets, foam sheets, and metal foils. Examples of materials for the plastic film or the like include polyester resins such as polyethylene terephthalate (PET), acrylic resins such as polymethyl methacrylate (PMMA), polycarbonate, triacetyl cellulose (TAC), polysulfone, polyarylate, polyimide, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, ethylene-propylene copolymers, and cyclic olefin polymers such as "ARTON" (a cyclic olefin polymer, manufactured by JSR Corporation) and "ZEONOR" (a cyclic olefin polymer, manufactured by Zeon Corporation). These plastic materials may be used alone or in combination of two or more.

The thickness of the substrate is not particularly limited, but is preferably 10 to 150 μm, more preferably 15 to 125 μm, and even more preferably 25 to 100 μm. The substrate may have either a single layer or multiple layers. The surface of the substrate may be appropriately subjected to a known, commonly used surface treatment, such as a physical treatment such as corona discharge treatment or plasma treatment, or a chemical treatment such as a primer treatment.

The above-mentioned pressure-sensitive adhesive sheet may have a release liner provided on the surface (adhesive surface or adhesive surface) of the pressure-sensitive adhesive layer, etc., until use. When the above-mentioned pressure-sensitive adhesive sheet is a double-sided pressure-sensitive adhesive sheet, each adhesive surface may be protected by two release liners, or it may be protected by a single release liner with release surfaces on both sides in a form wound into a roll (rolled body). The release liner is used as a protective material for the pressure-sensitive adhesive layer, and is peeled off when the sheet is attached to the adherend. When the above-mentioned pressure-sensitive adhesive sheet is a substrate-less pressure-sensitive adhesive sheet, etc., the release liner also serves as a support for the pressure-sensitive adhesive layer. It is not necessary to provide a release liner.

Examples of the configuration of the above-mentioned pressure-sensitive adhesive sheet include the configuration of pressure-sensitive adhesive sheet 10 shown in Figure 1: [adhesive layer/release liner], [release liner/adhesive layer/release liner], [substrate/adhesive layer/release liner], [release liner/adhesive layer/substrate/adhesive layer/release liner], or [substrate/adhesive layer/substrate/adhesive layer/release liner]. Among the above configurations, in configurations having two adhesive layers, at least one adhesive layer is the adhesive layer of the present invention, and from the viewpoint of being able to bend the adhesive sheet, it is preferable that both are the adhesive layer of the present invention. Furthermore, the arrangement shapes of the first region, second region, and other region in the two adhesive layers of the present invention may be the same or different.

The adhesive sheet of the present invention is not particularly limited in its application, and can be used for a variety of purposes. The adhesive sheet of the present invention can be used, for example, for optical applications, i.e., for bonding to optical components. The adhesive sheet of the present invention is used, for example, when attaching (mounting) various members or components to predetermined locations (e.g., housings) in optical components of electrical and electronic devices. Note that "electrical and electronic devices" refers to devices that fall into at least either electrical or electronic categories. Examples of such electrical and electronic devices include image display devices such as liquid crystal displays, electroluminescence displays, and plasma displays, as well as portable electronic devices. Examples of such image display devices include image display devices in the portable electronic devices, and displays (roll displays) inside and outside vehicles such as trains and buses.

Examples of the portable electronic devices include mobile phones, smartphones, tablet computers, notebook computers, various wearable devices (for example, wristwear devices worn on the wrist like a wristwatch, modular devices worn on a part of the body with a clip or strap, eyewear devices including glasses (monocular and binocular, including head-mounted devices), clothing devices attached to shirts, socks, hats, etc. as accessories, earwear devices attached to the ears like earphones), digital cameras, digital video cameras, audio equipment (portable music players, IC recorders, etc.), calculators (calculators, etc.), portable game devices, electronic dictionaries, electronic organizers, e-books, in-car information devices, portable radios, portable televisions, portable printers, portable scanners, portable modems, and the like. Note that, in this specification, "portable" does not simply mean that the device is portable; it also means that the device has a level of portability that allows it to be carried relatively easily by an individual (average adult).

When the pressure-sensitive adhesive sheet of the present invention is attached to an adherend and then folded, creases are unlikely to form at the folded portion. Therefore, the pressure-sensitive adhesive sheet of the present invention is preferably used for bonding components (particularly between components) in electrical and electronic devices that are used while being folded, such as electrical and electronic devices that have a foldable adherend, such as a foldable image display device (flexible display) (particularly a foldable image display device (foldable display)).

The pressure-sensitive adhesive sheet is also preferably used for, for example, bonding components or modules constituting a mobile electronic device together, or fastening components or modules constituting a mobile electronic device to a housing. More specifically, examples of such applications include bonding cover glass or lenses (especially glass lenses) to touch panels or touch sensor films (especially touch sensor films with metal wiring such as metal mesh films or silver nanowire films), bonding polarizing films to touch panels or touch sensors, bonding display panels to touch panels or touch sensor films, fixing cover glass or lenses (especially glass lenses) to housings, fixing display panels to housings, fixing input devices such as sheet keyboards and touch panels to housings, bonding protective panels for information display units to housings, bonding housings to housings, bonding housings to housings, bonding housings to decorative sheets, and fixing or bonding various components and modules constituting a mobile electronic device. Note that, in this specification, a display panel refers to a structure composed of at least a lens (especially a glass lens) and a touch panel. Note that, in this specification, the term "lens" is intended to encompass both transparent bodies that refract light and transparent bodies that do not. In other words, lenses in this specification also include window panels that do not have any refractive effect.

The above-mentioned adhesive sheet can also be suitably used for transparent conductive films (metal mesh films, silver nanowire films) in which the metal wiring is metal mesh wiring or silver nanowires, particularly optical components (touch sensor films) that have metal mesh films. When optical components that have metal wiring, such as metal mesh films or silver nanowire films, are bonded via the adhesive sheet, the low dielectric constant suppresses noise generation, while providing sufficient adhesive strength and excellent drop impact resistance.

The above-described embodiments have been described to facilitate understanding of the present invention and are not intended to limit the present invention.

The present invention will be explained in more detail below using examples, but the present invention is not limited to these examples in any way.

Example 1
(Preparation of Acrylic Prepolymer Solution)
In a reaction vessel equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 71 parts by mass of n-octyl acrylate (NOAA), 19 parts by mass of n-butyl acrylate (BA), 2 parts by mass of N-vinyl-2-pyrrolidone (NVP), 8 parts by mass of 4-hydroxybutyl acrylate (4HBA), 0.05 parts by mass of a photopolymerization initiator (trade name "Omnirad 819", manufactured by IGM Resins Italia Srl), and 0.05 parts by mass of a photopolymerization initiator (trade name "Omnirad 184", manufactured by IGM Resins Italia Srl) were added, and then nitrogen gas was flowed in and the atmosphere was replaced with nitrogen for about 20 minutes while stirring. Thereafter, polymerization was carried out by irradiating ultraviolet light at 5 mW/cm ² , and the reaction rate was adjusted to 5 to 15%, to obtain an acrylic prepolymer solution.

<Preparation of Acrylic Oligomer Solution>
First, in a reaction vessel equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, a mixture containing 60 parts by mass of dicyclopentanyl methacrylate (DCPMA), 40 parts by mass of methyl methacrylate (MMA), 3.5 parts by mass of α-thioglycerol as a chain transfer agent, and 100 parts by mass of toluene as a polymerization solvent was stirred at 70°C for 1 hour under a nitrogen atmosphere. Next, 0.2 parts by mass of 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator was added to the mixture to prepare a reaction solution, which was then reacted under a nitrogen atmosphere at 70°C for 2 hours and then at 80°C for 2 hours (polymerization reaction). Next, the reaction solution was heated to 130°C to volatilize and remove the toluene, chain transfer agent, and unreacted monomer. This resulted in an acrylic oligomer (solid). The weight-average molecular weight of this acrylic oligomer was 5100. This acrylic oligomer was dissolved in BA to a concentration of 50% by mass to obtain an acrylic oligomer solution.

(Preparation of Pressure-Sensitive Adhesive Composition 1)
To the acrylic prepolymer solution, 1 part by mass of 1,9-nonanediol diacrylate (NDDA) as a crosslinking agent, 1.5 parts by mass of the acrylic oligomer solution, 0.5 parts by mass of γ-glycidyloxypropyltrimethoxysilane as a silane coupling agent, and 0.02 parts by mass of a photopolymerization initiator (product name "Omnirad 819", manufactured by IGM Resins Italia Srl) were added and stirred to prepare PSA composition 1.

(Preparation of Pressure-Sensitive Adhesive Composition 2)
To the acrylic prepolymer solution, 0.1 parts by mass of 1,9-nonanediol diacrylate (NDDA) as a crosslinking agent, 1.5 parts by mass of the acrylic oligomer solution, 0.5 parts by mass of γ-glycidyloxypropyltrimethoxysilane as a silane coupling agent, and 0.02 parts by mass of a photopolymerization initiator (product name "Omnirad 819", manufactured by IGM Resins Italia Srl) were added and stirred to prepare PSA composition 2.

(Preparation of adhesive sheet)
As shown in Figure 7, the pressure-sensitive adhesive composition 1 (21) and the pressure-sensitive adhesive composition 2 (22) were arranged near edge E5 on the release-treated surface of a release liner 2 (trade name "MRE38", manufactured by Mitsubishi Chemical Corporation, a polyethylene terephthalate film with one side subjected to a release treatment, thickness 38 µm) in the following order: pressure-sensitive adhesive composition 1 (21), pressure-sensitive adhesive composition 2 (22), pressure-sensitive adhesive composition 1 (21), pressure-sensitive adhesive composition 2 (22), pressure-sensitive adhesive composition 1 (21). Thereafter, the applicator 3 was moved from edge E5 toward the other edge, thereby spreading pressure-sensitive adhesive composition 1 and pressure-sensitive adhesive composition 2 in one direction to form a pressure-sensitive adhesive composition layer (thickness 50 µm). The release-treated surface of a release liner (trade name "MRF38", manufactured by Mitsubishi Chemical Corporation) was then bonded to the pressure-sensitive adhesive composition layer. Next, polymerization was carried out by irradiating ultraviolet light using a black light at an illuminance of 2.5 mW/ ^cm² until the cumulative light dose reached 2400 mJ/ ^cm² . In this way, a pressure-sensitive adhesive sheet 10 was produced, which included a relatively hard first region 11 containing 1 part by mass of crosslinking agent and a relatively soft second region containing 0.1 parts by mass of crosslinking agent. The widths of the first and second regions in the resulting pressure-sensitive adhesive sheet 10 were each 20 mm.

<Measurement of Hardness of Pressure-Sensitive Adhesive Layer by Nanoindentation Method>
The pressure-sensitive adhesive layer obtained in Example 1 was cut into pieces of approximately 1 cm square, which were fixed to a support (a slide glass manufactured by Matsunami Glass Industry Co., Ltd.) to prepare a sample for nanoindentation measurement. Nanoindentation measurement was performed under the following conditions to obtain a load-displacement curve.
Nanoindentation measurement conditions: Apparatus: Triboindenter manufactured by Hysitron Inc.
Indenter used: Conical (spherical: radius 10 μm)
Measurement method: Single indentation measurement Measurement temperature: Room temperature Indentation depth: 5000 nm

The hardness H was calculated from the load (maximum load P _max ) applied when the indenter was pressed to the above-mentioned indentation depth and the contact area (contact projected area Ac) between the indenter and the sample at that time, using the following formula (1).
H=P _max /Ac (1)

Figure 8 shows a graph of the nanoindentation hardness near the first and second regions. As shown in Figure 8, in terms of hardness measured by nanoindentation, it was possible to produce an adhesive sheet having an adhesive layer with a first region, which is a relatively hard portion, and a second region, which is a relatively soft portion, in the same plane. Such an adhesive sheet can be folded for use, and when attached to an adherend and folded, creases are unlikely to occur at the folded portion.

Variations of the invention according to the present disclosure are described below.
[Supplementary Note 1] A pressure-sensitive adhesive layer having, in the same plane, a first region that is a single linear region and a second region that is parallel to the first region and is also a single linear region,
The pressure-sensitive adhesive sheet has different physical properties from the first region and the second region.
[Appendix 2] The pressure-sensitive adhesive sheet according to Appendix 1, wherein the physical property is hardness.
[Appendix 3] The pressure-sensitive adhesive sheet described in Appendix 1 or 2, wherein the hardness is one or more selected from the group consisting of tensile strength, modulus of elasticity, Young's modulus, elongation at break, stress at break, surface hardness, swelling degree, gel fraction, hardness measured by nanoindentation, and residual stress.
[Appendix 4] The pressure-sensitive adhesive sheet according to any one of Appendices 1 to 3, wherein the first region and the second region are each a single straight line.
[Appendix 5] The pressure-sensitive adhesive sheet according to any one of Appendices 1 to 4, wherein the first regions and the second regions are alternately arranged in one direction of the pressure-sensitive adhesive layer.
[Appendix 6] The pressure-sensitive adhesive sheet according to any one of Appendices 1 to 5, wherein the first region and the second region extend from one end side to the other end side in a direction perpendicular to the thickness direction of the pressure-sensitive adhesive layer.
[Appendix 7] The pressure-sensitive adhesive sheet described in Appendix 2, which is used by being attached to a foldable adherend, the first region is included in an area corresponding to the fold of the adherend, the second region is adjacent to both sides of the first region, and the hardness of the first region is harder than the hardness of the second region.
[Supplementary Note 8] The hardness of the first region is higher than the hardness of the second region;
The adhesive sheet described in Appendix 2, wherein in the adhesive layer, the first region and the second region are positioned alternately adjacent to each other in one direction of the adhesive layer, and the first region is located within a range of ±1 mm from the center in the one direction.
[Appendix 9] The pressure-sensitive adhesive sheet according to any one of Appendices 1 to 8, which is used by being attached to an optical member.
[Appendix 10] The pressure-sensitive adhesive sheet according to Appendix 9, which is used by being attached to a foldable adherend.

REFERENCE SIGNS LIST 1 Pressure-sensitive adhesive layer 2 Release liner 3 Applicator 10 Pressure-sensitive adhesive sheet 11 First region 12 Second region 21 Pressure-sensitive adhesive composition 1
22 Pressure-sensitive adhesive composition 2
B Bend portion D1 First direction D2 Second direction E1 First edge E2 Second edge E3 Third edge E4 Fourth edge E5 Fifth edge

Claims (10)

a pressure-sensitive adhesive layer having, in the same plane, a first region which is a single linear region and a second region which is a single linear region and is parallel to the first region;
The pressure-sensitive adhesive sheet has different physical properties from the first region and the second region. The adhesive sheet according to claim 1, wherein the physical property is hardness. The pressure-sensitive adhesive sheet according to claim 1 or 2, wherein the hardness is one or more selected from the group consisting of tensile strength, modulus of elasticity, Young's modulus, elongation at break, stress at break, surface hardness, swelling degree, gel fraction, hardness measured by nanoindentation, and residual stress. The adhesive sheet of claim 1 or 2, wherein the first region and the second region each have a single straight line shape. The adhesive sheet according to claim 1 or 2, wherein the first regions and the second regions are alternately arranged in one direction of the adhesive layer. The adhesive sheet according to claim 1 or 2, wherein the first region and the second region extend from one end to the other end in a direction perpendicular to the thickness direction of the adhesive layer. The pressure-sensitive adhesive sheet according to claim 2, which is used by being attached to a foldable adherend, the first region is included in an area corresponding to the fold of the adherend, the second region is adjacent to both sides of the first region, and the hardness of the first region is greater than the hardness of the second region. The hardness of the first region is greater than the hardness of the second region;
The pressure-sensitive adhesive sheet according to claim 2, wherein the first regions and the second regions are alternately adjacent to each other in one direction of the pressure-sensitive adhesive layer, and the first region is located within a range of ±1 mm from the center in the one direction. The pressure-sensitive adhesive sheet according to claim 1 or 2, which is used by being attached to an optical component. The pressure-sensitive adhesive sheet according to claim 9, which is used by being attached to a foldable adherend.