Method for manufacturing laminate, method for manufacturing two-dimensional material laminate, and two-dimensional material

Abstract

This method for manufacturing a laminate includes: a step for forming air bubbles between a first substrate and a two-dimensional material in a state in which a support layer has been attached to a two-dimensional material on the first substrate; and a step for separating the laminate including the support layer and the two-dimensional material from the first substrate by forming the bubbles or by pulling at least one of the support layer and the first substrate after forming the bubbles. The support layer has re-peelability, and the tensile elastic modulus of the laminate at 23°C is 10-3000 MPa.

Description

Manufacturing method of laminate, manufacturing method of two-dimensional material laminate and two-dimensional material

[0001] The present invention relates to a method for manufacturing a laminate, a method for manufacturing a two-dimensional material laminate, and a two-dimensional material.

[0002] Two-dimensional materials such as two-dimensional carbon materials are expected to have various applications such as wiring materials and transparent electrodes due to their excellent electrical and optical properties. ２ Graphene, a conductive planar crystal composed of bonded carbon atoms, has high optical transmittance and electrical conductivity, and is expected to be used in transparent conductive films, transparent electrodes, transistors, etc. Graphene is typically produced by chemical vapor deposition (CVD) on the surface of a catalytic metal. However, when graphene is used in a device, a process is required to separate and transfer the graphene formed on the catalytic metal.

[0003] Here, Patent Document 1 describes a method for separating graphene formed on a metal substrate over a large area, in which bubbles are formed at the interface between the graphene and the metal substrate, thereby separating a laminate made of graphene and a support layer from the surface of the metal substrate.

[0004] International Publication No. 2013 / 043120

[0005] Patent Literature 1 discloses a method for coating graphene with PMMA (polymethyl methacrylate) as a support layer, and then generating bubbles between the metal substrate and the graphene by an electrochemical method to separate the laminate of the support layer and graphene from the metal substrate. However, this method requires a solvent washing step to remove the PMMA coating layer when the graphene is subsequently transferred to a processing substrate, which poses a problem in productivity. Contamination by PMMA residue is also an issue.

[0006] Furthermore, as a result of extensive research, the present inventors have found a new problem: when the elastic modulus of the support layer is high, the air bubbles that contribute to separation escape from the edge of the laminate made of graphene and the support layer before they grow large, making separation over a large area difficult.

[0007] In view of the above, an object of the present disclosure is to provide a method for manufacturing a laminate including a two-dimensional material and a support layer, which can manufacture a laminate that can efficiently transfer a two-dimensional material with a high transfer rate and low contamination, even if the two-dimensional material has a large area.

[0008] The method for producing a laminate according to the present disclosure includes the steps of: forming bubbles between a first substrate and a two-dimensional material with a support layer attached to the first substrate; and separating a laminate including the support layer and the two-dimensional material from the first substrate by forming the bubbles or by pulling at least one of the support layer and the first substrate after forming the bubbles, wherein the support layer is removably removable, and the laminate has a tensile modulus of 10 to 3000 MPa at 23°C under the following measurement conditions: (Measurement conditions for the tensile modulus of the laminate) A sample of the laminate having a width of 10 mm and a length of 20 mm is chucked at 5 mm above and below in the longitudinal direction, and pulled at a rate of 50 mm / min. The initial tensile modulus is calculated from the slope of the stress-to-strain gradient at the point where the gradient is greatest between 10% strain and 100% strain.

[0009] Furthermore, the present disclosure provides a method for manufacturing a two-dimensional material laminate, the method including: placing the laminate obtained by the above-described method for manufacturing a laminate on a second substrate so that the surface of the laminate facing the two-dimensional material is in contact with the second substrate; and transferring the two-dimensional material onto the second substrate by peeling off the support layer to obtain a two-dimensional material laminate including the second substrate and the two-dimensional material.

[0010] The two-dimensional material of the present disclosure may also be a 100 mm ２ It is a two-dimensional material with an area of ​​at least 1000 mm.

[0011] According to the method for producing a laminate of the present disclosure, a laminate can be produced that can efficiently transfer a two-dimensional material with a high transfer rate and low contamination, even if the two-dimensional material has a large area. Furthermore, when the two-dimensional material is transferred to another substrate using the laminate, a two-dimensional material with little surface contamination can be obtained.

[0012] FIG. 1 is a schematic cross-sectional view showing a stack (first stack) having a two-dimensional material on a first substrate. FIG. 2 is a schematic cross-sectional view showing a state (second stack) in which a support layer is attached to the two-dimensional material on the first substrate. FIG. 3 is a schematic cross-sectional view showing a state in which air bubbles are formed between the first substrate and the two-dimensional material. FIG. 4 is a schematic cross-sectional view of a stack (third stack) including a support layer and a two-dimensional material. FIG. 5 is a schematic cross-sectional view showing a state (fourth stack) in which the stack (third stack) including a support layer and a two-dimensional material is placed on a second substrate so that the surface of the stack facing the two-dimensional material contacts the second substrate. FIG. 6 is a schematic cross-sectional view showing a process of obtaining a two-dimensional material stack including a second substrate and a two-dimensional material by peeling off the support layer from the fourth stack.

[0013] Hereinafter, embodiments of the present invention will be described in detail, but the present invention is not limited to such embodiments. In the following drawings, components and parts that perform the same function may be described using the same reference numerals, and duplicate descriptions may be omitted or simplified. The embodiments shown in the drawings are schematic to clearly explain the present invention, and do not necessarily accurately represent the size or scale of the actual product. In addition, when the expression "~" is used in this specification, it is used as an expression that includes the numerical values ​​or physical property values ​​before and after it.

[0014] [Method for manufacturing a laminate] A method for manufacturing a laminate according to one embodiment includes the steps of: forming bubbles between a first substrate and a two-dimensional material with a support layer attached to the two-dimensional material on the first substrate; and separating a laminate including the support layer and the two-dimensional material from the first substrate by forming the bubbles or by pulling at least one of the support layer and the first substrate after forming the bubbles, wherein the support layer is removably removable, and the laminate has a tensile modulus of 10 to 3000 MPa at 23°C under the following measurement conditions: (Measurement conditions for the tensile modulus of the laminate) A sample of the laminate having a width of 10 mm and a length of 20 mm is chucked at 5 mm above and below in the longitudinal direction, and pulled at a rate of 50 mm / min. The initial tensile modulus is calculated from the slope of the stress-to-strain gradient at the point where it is greatest between 10% strain and 100% strain.

[0015] 1 is a schematic cross-sectional view showing a stack 101 having a two-dimensional material 30 on a first substrate 21. The stack 101 may be referred to as a first stack. In the method for manufacturing a stack of this embodiment, as a preliminary step, first, the two-dimensional material 30 is formed on the first substrate 21.

[0016] The first substrate 21 is not particularly limited and may be a metal substrate, ceramic substrate, silicon substrate, resin substrate, etc. Examples of the first substrate 21 include metal substrates made of transition metals such as copper, nickel, cobalt, iron, chromium, gold, platinum, molybdenum, and tungsten; alloy metal substrates of these metals; single crystal substrates such as sapphire, magnesia, spinel, mica, SiC, SiN, and Si, and single crystal substrates whose surfaces have been oxidized; quartz substrates; substrates for forming two-dimensional materials on the surfaces of these substrates, on which thin films of the transition metals listed above are formed, and substrates on which two-dimensional materials are formed on the aforementioned substrates. The first substrate 21 is preferably a substrate for forming two-dimensional materials.

[0017] The method for forming the two-dimensional material on the metal substrate for film formation is not particularly limited, and a CVD method is preferably used. Examples of the film formation method include a thermal CVD method in which a raw material gas is introduced in the presence of a catalytic metal and processed by thermal decomposition of the raw material gas, and a surface wave microwave plasma chemical vapor deposition (CVD) method in which microwave plasma is used for processing. However, any method may be used as long as the two-dimensional material 30 can be formed on the first substrate 21.

[0018] The two-dimensional material 30 is a material having a two-dimensional layered structure made of a single element or two or more elements, and having an extremely thin sheet structure. Graphene, a two-dimensional sheet made only of carbon, is a typical example. The two-dimensional material 30 may also be a ribbon-like film having a width in the nanometer range. Examples of the two-dimensional material 30 include two-dimensional carbon materials, transition metal chalcogenides, molybdenum disulfide, tungsten disulfide, hexagonal boron nitride (h-BN), black phosphorus, and derivatives thereof. Two-dimensional carbon materials, molybdenum disulfide, tungsten disulfide, or hexagonal boron nitride are preferred. Graphene or graphene derivatives are preferred as the two-dimensional carbon material. Graphene is a two-dimensional carbon material consisting of sp ２ It is a film formed by bonded carbon atoms, forming a hexagonal lattice structure made of carbon atoms and their bonds. In this specification, multi-layer graphene, in which these films are stacked in 2 to 100 layers, is also referred to as "graphene." Furthermore, the two-dimensional material 30 may be composed of a single layer or multiple layers. When the two-dimensional material is composed of multiple layers, each layer may be composed of the same material or different materials.

[0019] Examples of graphene derivatives include graphene oxide, sulfonated graphene oxide, graphene hydroxide, graphene carbonate, and graphene nitride, and graphene oxide is preferred.

[0020] The laminate 101 may be subjected to a pretreatment process of immersion in water. For example, when the two-dimensional material is graphene and the graphene film-forming catalyst of the laminate 101 is Cu, the laminate 101 is immersed in water at 4 to 100°C for 4 to 72 hours. This treatment causes water to intercalate at the interface between the graphene and Cu, oxidizing the Cu surface. During immersion, the water may be left standing or stirred. Stirring the water makes the Cu surface more likely to oxidize. Other methods include adding a metal salt such as potassium chloride or sodium chloride to water to promote Cu oxidation, or contacting the water with water vapor to oxidize Cu. In either case, water intercalates at the interface between the graphene and Cu, oxidizing the Cu surface. This oxidation weakens the interaction between the graphene and Cu, allowing for effective transfer of the graphene to the support layer 10 in the subsequent process.

[0021] 2 is a schematic cross-sectional view showing a state in which the support layer 10 is attached to the two-dimensional material 30 on the first substrate 21. Here, the stack formed by attaching the support layer 10 to the two-dimensional material 30 on the first substrate 21 is referred to as the stack 102. Furthermore, the stack 102 in which the first substrate 21, the two-dimensional material 30, and the support layer 10 are stacked in this order may be referred to as the second stack. In the method for manufacturing a stack of this embodiment, the support layer 10 is attached to the two-dimensional material 30 on the first substrate 21.

[0022] By placing the support layer 10 on the two-dimensional material 30 side of the laminate 101 of the first substrate 21 and the two-dimensional material 30, the support layer 10 can be attached to the two-dimensional material 30. This results in a laminate 102. Here, when attaching the support layer 10 to the two-dimensional material 30, the two-dimensional material 30 and the support layer 10 may be pressed together using, for example, a roller or the like.

[0023] After obtaining the laminate 102, autoclave treatment may be performed as necessary. The conditions for the autoclave treatment are not particularly limited, but for example, the temperature is preferably 20 to 300°C, more preferably 30 to 70°C. The pressure is preferably 1.1 to 20 atmospheres, more preferably 2 to 10 atmospheres. The treatment time is preferably 1 to 120 minutes, more preferably 10 to 60 minutes.

[0024] 2 shows an embodiment in which an adhesive tape having a substrate 11 and an adhesive layer 12 is used as the support layer 10. However, this is merely one embodiment, and the support layer 10 may be any layer as long as it is removably removable.

[0025] (Pre-curing step) The method for producing a laminate of this embodiment may include a pre-curing step after the support layer attachment step and before the bubble formation step described below. The pre-curing step is optional. Here, the pre-curing step is a step of curing an adhesive layer when an adhesive tape having an adhesive layer that hardens upon receiving a predetermined energy or substance is used as the support layer 10. Hereinafter, an adhesive layer that hardens upon receiving a predetermined energy or substance may be referred to as a curable adhesive layer. An adhesive tape having a curable adhesive layer may also be referred to as a curable adhesive tape.

[0026] When a curable adhesive tape is used as the support layer 10, the adhesive layer 12 of the support layer 10 (curable adhesive tape) easily conforms to the shape of the two-dimensional material in the support layer attachment process described above. Furthermore, by performing a curing process before the bubble formation process and separation process described below, the support layer 10 (curable adhesive tape) becomes hard enough to suppress deformation of the two-dimensional material 30 when separating a laminate including the support layer 10 and the two-dimensional material 30 from the first substrate 21 in the separation process. Therefore, the two-dimensional material 30 can be separated from the first substrate 21 over a large area and with little or no damage. As a result, a two-dimensional material with a high transfer rate is easily obtained. In one aspect, when the two-dimensional material is graphene, graphene with a high transfer rate and high mobility is easily obtained.

[0027] The curable adhesive layer and the curable adhesive tape will be described in more detail in the description of the "support layer" below.

[0028] (Gas Bubble Formation Process) FIG. 3 is a schematic cross-sectional view showing a state in which a gas bubble B is formed between the first substrate 21 and the two-dimensional material 30. FIG. 3 also shows how the laminate 103 including the support layer 10 and the two-dimensional material 30 is separated from the first substrate 21 due to the formation of the gas bubbles in the gas bubble formation process. In the laminate manufacturing method of this embodiment, a gas bubble B is subsequently formed between the first substrate 21 and the two-dimensional material 30. Here, a gas bubble forming unit 260 is used to form the gas bubble B between the first substrate 21 and the two-dimensional material 30. The gas bubble forming unit 260 includes at least a solution 261, a potential source 262 (e.g., a power source or a battery) having a positive lead 262P and a negative lead 262N, and an anode 263 located in the solution 261 and electrically connected to the positive lead 262P.

[0029] The laminate (second laminate) 102 is immersed in the solution 261 of the bubble forming unit 260. With the laminate (second laminate) 102 immersed in the solution 261, the negative lead 262N is electrically connected to the first substrate 21 in the solution 261. Therefore, the first substrate 21 functions as the cathode of the bubble forming unit 260.

[0030] That is, the formation of bubbles B between the first substrate 21 and the two-dimensional material 30 is performed by, for example, an electrochemical reaction in the bubble formation unit 260. As an example, the electrochemical reaction is the release of hydrogen due to electrolysis of water in the solution 261, and bubbles B are formed by the electrochemical reaction.

[0031] More specifically, when a potential is applied to the solution 261, a reduction reaction occurs on the negatively charged first substrate 21 (cathode), hydrogen gas is formed from the first substrate 21, and hydrogen bubbles B are formed on the conductive surface of the first substrate 21. As a result, bubbles B are formed between the first substrate 21 and the two-dimensional material 30. Here, in the bubble forming unit 260, the arrangement of the anode 263 is adjusted so that bubbles B are formed in a concentrated manner between the first substrate 21 and the two-dimensional material 30.

[0032] The solution 261 contains water and at least one electrolyte, preferably 0.01 to 10 moles of electrolyte per liter of water. The electrolyte is not particularly limited and may be a single type or a combination of two or more types. Examples of the electrolyte include sodium hydroxide, potassium hydroxide, sulfuric acid, sodium chloride, and any suitable combination thereof.

[0033] (Separation Process) The method for manufacturing a laminate according to this embodiment includes a process for separating the laminate 103 including the support layer 10 and the two-dimensional material 30 from the first substrate 21. FIG. 4 shows a schematic cross-sectional view of the laminate 103 including the support layer 10 and the two-dimensional material 30. The laminate 103 may also be referred to as a third laminate. Separation of the laminate 103 including the support layer 10 and the two-dimensional material 30 from the first substrate 21 may occur by the formation of bubbles in the bubble formation process described above, as shown in FIG. 3. In this case, the bubble formation process and the separation process can be said to be performed simultaneously. Alternatively, separation of the laminate 103 including the support layer 10 and the two-dimensional material 30 from the first substrate 21 may be performed by pulling at least one of the support layer 10 and the first substrate 21 after the bubble formation process described above.

[0034] The laminate 103 separated from the first substrate 21 may be washed with an appropriate cleaning liquid such as ion-exchanged water, pure water such as distilled water, ultrapure water, or alcohol such as ethanol or isopropyl alcohol, if necessary.

[0035] In the manufacturing method of this embodiment, the tensile modulus of the laminate 103 including the support layer 10 and the two-dimensional material 30 is 10 to 3000 MPa. Here, from the viewpoint of ease of handling, the tensile modulus of the laminate 103 is preferably 10 MPa or more, more preferably 40 MPa or more, and even more preferably 70 MPa or more. Furthermore, the tensile modulus of the laminate 103 is preferably 3000 MPa or less, more preferably 2000 MPa or less, even more preferably 1000 MPa or less, and even more preferably 100 MPa or less. When the tensile modulus of the laminate 103 is 3000 MPa or less, when bubbles are formed between the first substrate 21 and the two-dimensional material 30, it is possible to suppress or prevent the bubbles that contribute to separation from escaping from the edge of the laminate 103 before they become large. Furthermore, when the tensile modulus of the laminate 103 is within the above range, it is believed that the laminate 103 is appropriately separated from the first substrate 21 in the separation process, and good low-contamination properties are achieved. The tensile modulus of the laminate 103 is the tensile modulus at 23°C, and may be calculated for the laminate 103 separated from the first substrate 21. The tensile modulus of the laminate 103 separated from the first substrate can be considered to be substantially the same as the tensile modulus of the laminate 103 at the time of bubble formation. Furthermore, since the thickness of the two-dimensional material 30 is usually sufficiently thin compared to the thickness of the support layer 10, it can be said that the two-dimensional material 30 does not substantially affect the modulus of the laminate 103. Therefore, the tensile modulus of the laminate 103 can usually be considered to be substantially the same as the tensile modulus of the support layer 10.

[0036] The tensile modulus of the laminate can be calculated specifically as follows. A 10 mm wide x 20 mm long sample of a laminate (third laminate) of a support and a two-dimensional material is prepared, chucked at 5 mm above and below the longitudinal direction with a chuck distance of 10 mm, and pulled at a speed of 50 mm / min. The initial tensile modulus is calculated from the slope of the stress-to-strain gradient at the maximum point between 10% strain and 100% strain using a tensile tester, and this is the tensile modulus of the laminate (third laminate). If the tensile modulus has anisotropy that varies depending on the pulling direction, the average of the tensile modulus when pulled in at least two orthogonal directions in the plane is used. For example, the average of the values ​​measured in two orthogonal directions in the plane (MD and TD) as the long side direction (length direction) is used.

[0037] Furthermore, when separating the laminate 103 from the first substrate 21 by pulling at least one of the support layer 10 and the first substrate 21 after the bubble formation process, the peel angle is not particularly limited and is typically 180 degrees or less. However, a small peel angle can prevent defects such as tears and cracks from occurring in the two-dimensional material 30 due to changes in the shape of the laminate 103. For this reason, a small peel angle is preferable, preferably 90 degrees or less, and more preferably 60 degrees or less. Furthermore, from the perspective of increasing the size of the peeling device itself, the peel angle is preferably 0 degrees or more. The peel angle refers to the angle between the first substrate 21 and the peeled portion of the laminate 103 when separating the laminate 103 from the first substrate 21.

[0038] The peeling speed when separating the laminate 103 from the first substrate 21 is not particularly limited, but a fast peeling speed shortens the time it takes for the shape of the laminate 103 to change, thereby preventing defects such as tears and cracks from occurring in the two-dimensional material 30. For this reason, the peeling speed is typically 1 mm / min or higher, but a fast peeling speed is preferable, preferably 10 mm / min or higher, and more preferably 100 mm / min or higher. Furthermore, from the viewpoint of stable operation of the device, the peeling speed is preferably 100,000 mm / min or lower, and more preferably 90,000 mm / min or lower. The peeling speed refers to the length of the laminate 103 peeled from the laminate 102 per unit time when separating the laminate 103 from the laminate 102.

[0039] According to the laminate manufacturing method of this embodiment, bubbles that release the interaction between the first substrate 21 and the two-dimensional material 30 with a gentle force can be efficiently formed, so that the two-dimensional material 30 can be separated without tearing or scratching even if the two-dimensional material 30 has a large area. As a result, even if the two-dimensional material 30 has a large area, it is possible to manufacture a laminate 103 that can efficiently transfer the two-dimensional material 30 at a high transfer rate. Note that a large area is, for example, 100 mm ２ Although the areas are as described above, the method for manufacturing a laminate of this embodiment is naturally applicable even when the area of ​​the two-dimensional material is relatively small, and it is easily understood that this method also includes such cases.

[0040] [Method for manufacturing two-dimensional material laminate] In one embodiment, a method for manufacturing a two-dimensional material laminate includes the steps of: placing the laminate obtained by the above-described method for manufacturing a laminate on a second substrate so that the surface of the laminate facing the two-dimensional material is in contact with the second substrate; and transferring the two-dimensional material onto the second substrate by peeling off the support layer, thereby obtaining a two-dimensional material laminate including the second substrate and the two-dimensional material.

[0041] (Placement Step) In the method for manufacturing a two-dimensional material stack of this embodiment, first, the stack obtained by the above-described method for manufacturing a stack is placed on a second substrate so that the surface of the stack on the two-dimensional material side contacts the second substrate. Figure 5 is a schematic cross-sectional view showing the step (placing step) of placing the stack 103 on the second substrate 40 so that the surface of the stack 103 on the two-dimensional material 30 side contacts the second substrate 40. By the placing step, a stack 104 is obtained in which the second substrate 40 and the stack 103 are stacked.

[0042] Here, when placing the laminate 103 on the second substrate 40, the laminate 103 may be wetted with an appropriate liquid such as water or alcohol, placed on the second substrate (liquid application), and then left to stand or dried, as necessary. This can increase the adhesion of the laminate 103 to the second substrate 40. Furthermore, when placing the laminate 103 on the second substrate 40, the laminate 103 and the second substrate 40 may be pressed together using, for example, a roller or the like. Furthermore, the laminate 103 may be cut to an appropriate size and placed at any desired location on the second substrate 40. This allows the two-dimensional material to be placed at any desired location on the second substrate.

[0043] (Post-curing step) The method for producing a two-dimensional material laminate of this embodiment may include a post-curing step after the placing step and before the transfer step described below. The post-curing step is optional. Here, the post-curing step refers to a step of curing an adhesive layer when an adhesive tape having an adhesive layer that hardens upon receiving a predetermined energy or substance is used as the support layer 10. However, the post-curing step is performed after the bubble-incorporating step in the method for producing a laminate described above, and is distinguished from the pre-curing step that is performed before the bubble-incorporating step.

[0044] Specifically, when a curable adhesive tape is used as the support layer 10, the adhesive layer 12 of the support layer 10 (curable adhesive tape) easily conforms to the shape of the two-dimensional material 30 in the support layer attachment step described above. Furthermore, by performing a post-curing step before the transfer step described below, the adhesive strength of the adhesive layer 12 of the support layer 10 (curable adhesive tape) is reduced, making it easier to peel the support layer 10 (curable adhesive tape) from the two-dimensional material 30 in the transfer step. As a result, a high transfer rate is easily obtained. In one aspect, when the two-dimensional material is graphene, graphene having a high transfer rate and high mobility is easily obtained.

[0045] In this embodiment, either the pre-curing step or the post-curing step may be performed, but from the viewpoint of easily obtaining a higher transfer rate and mobility, it is preferable to perform the pre-curing treatment.

[0046] (Transfer Process) In the method for manufacturing a two-dimensional material stack of this embodiment, the two-dimensional material is subsequently transferred onto a second substrate by peeling off the support layer, thereby obtaining a two-dimensional material stack including the second substrate and the two-dimensional material. Figure 6 is a schematic cross-sectional view showing the process of transferring the two-dimensional material 30 onto the second substrate 40 by peeling off the support layer 10. By peeling off the support layer 10 of the stack 104, the two-dimensional material 30 is transferred onto the second substrate 40, thereby obtaining a stack 105 including the second substrate 40 and the two-dimensional material 30. This stack 105 including the second substrate 40 and the two-dimensional material 30 is sometimes referred to as a two-dimensional material stack.

[0047] The peel angle when peeling the support layer 10 from the laminate 104 is not particularly limited and is usually 180 degrees or less. However, if the peel angle is large, stress is concentrated at the peel tip of the support layer 10, reducing the peel force at the interface between the support layer 10 and the two-dimensional material 30, thereby preventing defects such as tears and cracks from occurring in the two-dimensional material 30. For this reason, the peel angle is preferably large, preferably 90 degrees or more, and more preferably 120 degrees or more. Furthermore, from the viewpoint of the peeling mechanism, the peel angle is preferably 180 degrees or less. The peel angle refers to the angle between the two-dimensional material 30 and the peeled portion of the support layer 10 when peeling the support layer 10 from the laminate 104.

[0048] The peeling speed when peeling the support layer 10 from the laminate 104 is not particularly limited, but if the peeling speed is slow, the elastic properties of the support layer 10 will be reduced, thereby reducing the peel force at the interface between the support layer 10 and the two-dimensional material 30, thereby preventing defects such as tearing and cracking in the two-dimensional material 30. For this reason, the peeling speed is usually 1000 mm / min or less, but a slower peeling speed is preferable, preferably 600 mm / min or less, and more preferably 300 mm / min or less. Furthermore, from the viewpoint of stable operation of the device, the peeling speed is preferably 3 mm / min or more, and more preferably 10 mm / min or more. The peeling speed refers to the length of the support layer 10 peeled from the laminate 104 per unit time when peeling the support layer 10 from the laminate 104.

[0049] The second substrate 40 is a material onto which a two-dimensional material is transferred. The second substrate 40 is preferably a substrate in which the adhesive strength between its transfer surface and the two-dimensional material 30 is stronger than the adhesive strength between the adhesive layer 12 and the two-dimensional material 30 after a predetermined energy or substance is applied. Such a second substrate 40 may have a strong interacting force by itself, or may have an interacting force imparted by surface processing. Examples of surface processing include, but are not limited to, applying a curable resin, melting the surface, forming a microstructure, and chemically modifying the surface.

[0050] The second substrate 40 is not particularly limited, and may be any of a metal substrate, a ceramic substrate, a silicon substrate, a resin substrate, etc. The second substrate 40 may be, for example, a SiO ２ / Si substrate, quartz substrate, glass substrate, PET substrate, sapphire substrate, ITO substrate, substrate with two-dimensional material laminated thereon are preferred, SiO ２A / Si substrate is more preferred. Furthermore, the second substrate 40 may be a substrate in which a film made of copper, nickel, iron, or a mixed oxide containing at least one of these is partially formed on the surface of an appropriate base substrate such as a metal substrate, ceramic substrate, silicon substrate, or resin substrate. Here, the area occupied by the film in the area of ​​the surface of the base substrate is preferably 80% or less, and more preferably 70% or less. Furthermore, the area occupied by the film in the area of ​​the surface of the base substrate is preferably 5% or more, and more preferably 15% or more.

[0051] The thickness of the second substrate 40 is not particularly limited and can be selected appropriately, but is preferably 1 μm or more, more preferably 10 μm or more, and even more preferably 100 μm or more, and from the viewpoint of handling, is preferably 100 mm or less, more preferably 20 mm or less, and even more preferably 5 mm or less.

[0052] The two-dimensional material laminate obtained by the method for producing a two-dimensional material laminate according to this embodiment can be applied to transparent conductive films for touch panels and the like, semiconductor devices or electronic devices such as transistors and integrated circuits, transparent electrodes and electrochemical electrodes that require a large area, and the like.

[0053] Two-dimensional material In one embodiment, the two-dimensional material is a 100 mm ２ It is a two-dimensional material with an area of ​​at least 1000 mm.

[0054] The two-dimensional material of this embodiment can be obtained, for example, as a two-dimensional material in a two-dimensional material stack manufactured by the above-mentioned method for manufacturing a two-dimensional material stack.

[0055] The substrate on which the two-dimensional material is laminated can be any of the various substrates exemplified above as the second substrate. When the two-dimensional material is graphene, it is preferable to use a substrate that does not have copper, nickel, or iron on the outermost surface.

[0056] In addition, the two-dimensional material of this embodiment is 100 mm ２ The area of ​​the two-dimensional material is preferably 200 mm or more.２ More preferably, it is 7000 mm or more. ２ The upper limit of the area of ​​the two-dimensional material is not particularly limited, but is 200,000 mm ２ The following is practical:

[0057] Furthermore, the transfer rate of the two-dimensional material is preferably 50% or more, more preferably 70% or more, even more preferably 90% or more, and particularly preferably 95% or more. Here, the transfer rate of the two-dimensional material can be calculated as described in the Examples. In the Examples, for a two-dimensional material (graphene) transferred onto a substrate measuring 10 mm long x 20 mm wide, the area ratio of graphene at a total of nine points, including one central point and eight points near the edges (four vertices and four intermediate points between them), is calculated as a percentage, and the average value of the area ratios of graphene at these nine points (nine-point average transfer rate) is used as the transfer rate (%). However, if the size or shape of the substrate is different, the nine measurement points can be determined with reference to the cases described in the Examples.

[0058] The contamination level of the two-dimensional material is preferably -30% or more and 10% or less, more preferably -25% or more and 8% or less, and even more preferably -20% or more and 5% or less. The contamination level can be negative because pre-transfer residue may be removed during the transfer process. If the contamination level of the two-dimensional material is below -30%, the quality of the two-dimensional material before transfer will be reduced due to excessive pre-transfer residue. If the contamination level of the two-dimensional material is above 10%, the performance of the two-dimensional material after transfer will be reduced due to excessive post-transfer residue. The contamination level is calculated as the increase in the amount of carbon element calculated by ESCA analysis of the two-dimensional material stacked on an oxide-film-covered silicon substrate (SUMCO Corporation, silicon (crystal plane (100)), surface thermal oxidation - oxide film thickness 300 nm) relative to the amount of carbon element calculated by the same measurement on the surface of the two-dimensional material on the first substrate before the support layer is attached. The amount of carbon in each sample is determined as the atomic percentage of carbon in the total amount of the five elements, carbon, nitrogen, oxygen, silicon, and copper, by narrow-scan analysis using X-ray photoelectron spectroscopy (ESCA) on the target substrate surface. The analyzer used may be a Quantum 2000 manufactured by ULVAC PHI or an equivalent. More specifically, the amount of contamination can be determined by the method described in the Examples below.

[0059] In addition, when the two-dimensional material is graphene, the mobility of graphene is 2000 cm ２ / V / s or more, and ２ / V / s or more, and 4000 cm ２ The mobility of the two-dimensional material can be calculated by the method described in the examples.

[0060] (Support Layer) The support layer used in the laminate manufacturing method of this embodiment is not particularly limited as long as it has removability, and examples thereof include adhesive tape and adsorption sheets. Among them, adhesive tape is preferred as the support layer because the adhesive layer contained in adhesive tape is a viscoelastic body, which can wet and spread on two-dimensional materials and facilitates large-area pickup. In the laminate manufacturing method of this embodiment, since the support layer has removability, it is thought that good low-contamination properties can be obtained. In this specification, removability refers to the property that allows an article attached to an adherend to be easily peeled off from the adherend when peeling it off.

[0061] The adhesive strength A of the support layer to a silicon wafer at 23°C (180° peel strength from the silicon wafer) is preferably 0.001 N / 20 mm to 2.0 N / 20 mm when a 180° peel is performed at a tensile speed of 300 mm / min. From the viewpoint of handleability, the adhesive strength A is preferably 0.001 N / 20 mm or more, more preferably 0.01 N / 20 mm or more, even more preferably 0.03 N / 20 mm or more, and even more preferably 0.05 N / 20 mm or more. Furthermore, from the viewpoint of good removability, the adhesive strength A is preferably 2.0 N / 20 mm or less, more preferably 1.0 N / 20 mm or less, even more preferably 0.5 N / 20 mm or less, and even more preferably 0.1 N / 20 mm or less. When the support layer is a curable adhesive tape as described below, the adhesive strength A may vary depending on whether or not the adhesive layer is cured and the timing of curing, but it is preferable that the adhesive strength A at least after curing of the adhesive layer satisfies the above range.

[0062] Furthermore, the adhesive strength B at 23°C when peeling the support layer from the two-dimensional material (180° peel force when releasing the two-dimensional material) is preferably 0.001 N / 20 mm to 2.0 N / 20 mm when performing a 180° peel at a pulling speed of 300 mm / min. From the viewpoint of handleability, the adhesive strength B is preferably 0.001 N / 20 mm or more, more preferably 0.01 N / 20 mm or more, even more preferably 0.05 N / 20 mm or more, and even more preferably 0.1 N / 20 mm or more. From the viewpoint of good removability, the adhesive strength B is preferably 2.0 N / 20 mm or less, more preferably 1.5 N / 20 mm or less, even more preferably 0.5 N / 20 mm or less, and even more preferably 0.2 N / 20 mm or less. In addition, when the support layer is a curable adhesive tape described below, the adhesive strength B may change depending on whether or not the adhesive layer is cured and the timing of curing, but it is preferable that the adhesive strength B at least when peeling the support layer from the two-dimensional material satisfies the above range.

[0063] Examples of the adsorption tape used as the support layer include foam sheets and gel sheets made of acrylic resin, rubber, etc.

[0064] The adhesive tape used as the support layer is not particularly limited as long as it has an adhesive layer, and examples thereof include adhesive tapes in a substrate-less form consisting only of an adhesive layer, and adhesive tapes in a substrate-attached form comprising an adhesive layer and a substrate. Among these, from the viewpoint of ease of handling, adhesive tapes in a form comprising an adhesive layer on one side of a substrate (single-sided adhesive tape) are preferred. The concept of adhesive tape here may include those referred to as adhesive sheets, adhesive films, adhesive labels, etc.

[0065] The adhesive tape may be an adhesive tape having a non-curable adhesive layer, but is preferably a curable adhesive tape having an adhesive layer (curable adhesive layer) that cures upon receiving a predetermined energy or substance. Examples of the predetermined energy supplied to cure the adhesive layer include active energy rays and heat, with active energy rays being preferred. Examples of active energy rays include ionizing radiation such as α-rays, β-rays, γ-rays, X-rays, neutron beams, and electron beams, as well as ultraviolet light and visible light. From the viewpoints of versatility in consideration of the scale of the apparatus and reduction of damage to materials, radiation such as electron beams, ultraviolet light, α-rays, β-rays, γ-rays, and X-rays is preferred, with ultraviolet light being particularly preferred. That is, the adhesive layer is preferably an active energy ray-curable adhesive layer that cures upon irradiation with active energy rays, more preferably a radiation-curable adhesive layer that cures upon radiation irradiation, and even more preferably an ultraviolet-curable adhesive layer that cures upon ultraviolet irradiation. The method for generating ultraviolet light is not particularly limited, and well-known and commonly used generation methods can be used, such as a discharge lamp (arc lamp), flash, laser, and UV-LED. In the present invention, the use of a discharge lamp (arc lamp) or UV-LED method is preferred due to their excellent industrial productivity. Among these, the use of a high-pressure mercury lamp, metal halide lamp, or UV-LED irradiation method is preferred due to their excellent irradiation efficiency. The wavelength of the ultraviolet light can be any wavelength in the ultraviolet region, but wavelengths of approximately 250 to 440 nm, which are commonly used in photopolymerization, are preferred. Furthermore, materials supplied to cure the pressure-sensitive adhesive layer include curing agents, moisture, reactive compounds, and the like.

[0066] Examples of polymers contained in the pressure-sensitive adhesive layer include known or commonly used polymers, such as (meth)acrylic polymers, urethane acrylate polymers, urethane polymers, rubber polymers, epoxy polymers, epoxy acrylate polymers, oxetane polymers, silicone polymers, silicone acrylic polymers, polyester polymers, polyether polymers (such as polyvinyl ether), polyamide polymers, fluorine-containing polymers, vinyl acetate / vinyl chloride copolymers, and modified polyolefins. One or more of the above polymers may be used. Among these, (meth)acrylic polymers are preferred. The use of (meth)acrylic polymers facilitates adjustment of the storage modulus and tensile modulus of the pressure-sensitive adhesive layer, and also allows for the production of a pressure-sensitive adhesive composition with an excellent balance between adhesive strength and releasability. Furthermore, contamination of the adherend by components derived from the pressure-sensitive adhesive can be reduced. In this specification, "(meth)acrylic" refers to "acrylic" and / or "methacrylic" (either one or both of "acrylic" and "methacrylic"), and the same applies to other terms.

[0067] When the pressure-sensitive adhesive layer is an active energy ray-curable pressure-sensitive adhesive layer, examples of the pressure-sensitive adhesive layer include a pressure-sensitive adhesive layer containing a polymer having a radiation-polymerizable functional group as a base polymer, and a pressure-sensitive adhesive layer containing a base polymer and a radiation-polymerizable monomer component or oligomer component having a functional group such as a radiation-polymerizable carbon-carbon double bond. Combinations of these may also be used.

[0068] The following description focuses on pressure-sensitive adhesives containing a polymer having a radiation-polymerizable functional group as a base polymer. Examples of the radiation-polymerizable functional group include radiation-radical polymerizable groups (radical-reactive groups), such as groups containing a carbon-carbon unsaturated bond, such as ethylenically unsaturated groups, and radiation-cationically polymerizable groups. Examples of the group containing a carbon-carbon unsaturated bond include vinyl groups, propenyl groups, isopropenyl groups, acryloyl groups, and methacryloyl groups. Examples of the radiation-cationically polymerizable group include epoxy groups, oxetanyl groups, and oxolanyl groups. Among these, groups containing a carbon-carbon unsaturated bond are preferred, with acryloyl groups and methacryloyl groups being more preferred. The radiation-polymerizable functional group may be of one type or two or more types. The radiation-polymerizable functional group may be located in the polymer side chain, in the polymer main chain, or at the end of the polymer main chain.

[0069] Hereinafter, an active energy ray-curable pressure-sensitive adhesive composition containing a polymer having a radical-reactive carbon-carbon double bond as a base polymer will be described, which is a preferred embodiment of a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer in a pressure-sensitive adhesive tape.

[0070] In this embodiment, the pressure-sensitive adhesive composition is an active energy ray-curable pressure-sensitive adhesive composition containing a polymer having a radical-reactive carbon-carbon double bond (hereinafter also referred to as a carbon-carbon unsaturated double bond) at a side chain and / or terminal as a base polymer. The base polymer is preferably a polymer having a carbon-carbon unsaturated double bond at least at a side chain.

[0071] Examples of the base polymer include (meth)acrylic polymers, vinyl alkyl ether polymers, silicone polymers, polyester polymers, polyamide polymers, urethane polymers, and styrene-diene block copolymers, and preferably, (meth)acrylic polymers are used.

[0072] The weight-average molecular weight of the base polymer is preferably 300,000 or more, more preferably 400,000 or more, and even more preferably 600,000 to 1,000,000. Within these ranges, bleeding of low molecular weight components can be prevented, and a low-staining PSA composition can be obtained. The molecular weight distribution (weight-average molecular weight / number-average molecular weight) of the base polymer is preferably 1 to 20, and more preferably 3 to 10. By using a base polymer with a narrow molecular weight distribution, bleeding of low molecular weight components can be prevented, and a low-staining PSA composition can be obtained. The weight-average molecular weight and number-average molecular weight can be determined by gel permeation chromatography (solvent: tetrahydrofuran, polystyrene equivalent).

[0073] One aspect of the pressure-sensitive adhesive composition used in the pressure-sensitive adhesive tape of this embodiment contains a base polymer and a photopolymerization initiator. This base polymer is, for example, a polymer obtained by reacting a monomer composition containing a polymer and a monomer having a carbon-carbon unsaturated double bond. In this example, appropriate components are appropriately selected so that the carbon-carbon unsaturated double bond is introduced into the polymer. In this specification, the monomer composition may be a composition containing only a monomer, or may be a composition containing a monomer and any other components such as an oligomer and a polymer.

[0074] The base polymer can be obtained, for example, by reacting a polymer having a hydroxyl group with a monomer composition (hereinafter also referred to as base polymer monomer composition 1) containing a monomer having an isocyanate group and a functional group containing a carbon-carbon unsaturated double bond. By reacting base polymer monomer composition 1, the polymer having a hydroxyl group can undergo an addition reaction with the monomer having an isocyanate group and a functional group containing a carbon-carbon unsaturated double bond. As a result, a polymer having structural units derived from the monomer having an isocyanate group and a functional group containing a carbon-carbon unsaturated double bond is obtained.

[0075] The polymer having a hydroxyl group can be any suitable polymer having a hydroxyl group introduced therein. Examples include polymers having a hydroxyl group introduced into a (meth)acrylic polymer, a vinyl alkyl ether polymer, a silicone polymer, a polyester polymer, a polyamide polymer, a urethane polymer, a styrene-diene block copolymer, or the like. Preferably, a polymer having a hydroxyl group introduced into a (meth)acrylic polymer is used.

[0076] The (meth)acrylic polymer having a hydroxyl group can be obtained, for example, by polymerizing a monomer composition containing any suitable acrylic or methacrylic acid ester having a linear or branched alkyl group and a monomer having a hydroxyl group. The acrylic or methacrylic acid ester having a linear or branched alkyl group may be used alone or in combination of two or more.

[0077] The linear or branched alkyl group is preferably an alkyl group having 30 or less carbon atoms, more preferably an alkyl group having 1 to 20 carbon atoms, and even more preferably an alkyl group having 4 to 18 carbon atoms. Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an isobutyl group, an amyl group, an isoamyl group, a hexyl group, a heptyl group, a cyclohexyl group, a 2-ethylhexyl group, an octyl group, an isooctyl group, a nonyl group, an isononyl group, a decyl group, an isodecyl group, an undecyl group, a lauryl group, a tridecyl group, a tetradecyl group, a stearyl group, an octadecyl group, and a dodecyl group.

[0078] Any appropriate monomer can be used as the hydroxyl group-containing monomer. Examples include 2-hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxymethyl methacrylate, 2-hydroxyethyl methacrylate, and N-(2-hydroxyethyl)acrylamide. Preferably, 2-hydroxymethyl acrylate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, 2-hydroxymethyl methacrylate, and 2-hydroxyethyl methacrylate are used. These monomers may be used alone or in combination of two or more.

[0079] The hydroxyl group-containing monomer preferably accounts for 5 mol% to 40 mol%, more preferably 15 mol% to 30 mol%, and even more preferably 20 mol% to 25 mol%, based on 100 mol% of all monomer components in the monomer composition used in the polymerization of the hydroxyl group-containing polymer. Polymerization of a monomer composition containing a hydroxyl group-containing monomer produces a polymer containing hydroxyl groups. This hydroxyl group can serve as the introduction point for a structural unit derived from a monomer having a functional group containing a carbon-carbon unsaturated double bond and an isocyanate group. For example, a base polymer having a carbon-carbon unsaturated double bond can be obtained by reacting a polymer (prepolymer) containing hydroxyl groups with a monomer having a functional group containing a carbon-carbon unsaturated double bond and an isocyanate group.

[0080] For the purpose of modifying cohesive strength, heat resistance, crosslinkability, etc., other monomer components copolymerizable with the above-mentioned (meth)acrylic acid alkyl ester may be further used as necessary. Examples of such monomer components include carboxyl group-containing monomers such as acrylic acid and methacrylic acid; acid anhydride monomers such as maleic anhydride and itaconic anhydride; sulfonic acid group-containing monomers such as styrenesulfonic acid and allylsulfonic acid; (N-substituted) amide monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, and acryloylmorpholine; aminoalkyl (meth)acrylate monomers such as aminoethyl (meth)acrylate; alkoxyalkyl (meth)acrylate monomers such as methoxyethyl (meth)acrylate; maleimide monomers such as N-cyclohexylmaleimide and N-isopropylmaleimide; itaconimide monomers such as N-methylitaconimide and N-ethylitaconimide; succinimide vinyl monomers such as vinyl acetate, vinyl propionate, N-vinylpyrrolidone, and methylvinylpyrrolidone; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; glycol-based acrylic ester monomers such as polyethylene glycol (meth)acrylate and polypropylene glycol (meth)acrylate; acrylic ester monomers having a heterocycle, halogen atom, silicon atom, or the like, such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicone (meth)acrylate; olefin-based monomers such as isoprene, butadiene, and isobutylene; and vinyl ether-based monomers such as vinyl ether. These monomer components may be used alone or in combination of two or more.

[0081] The content of the other monomer component copolymerizable with the (meth)acrylic acid alkyl ester in the monomer composition can be any appropriate amount. Specifically, the other monomer component copolymerizable with the (meth)acrylic acid alkyl ester is used so that the total of the (meth)acrylic acid alkyl ester, the hydroxyl group-containing monomer, and any other monomer component copolymerizable with the (meth)acrylic acid alkyl ester is 100 mol %.

[0082] The polymer having a hydroxyl group can be obtained by any suitable method. For example, a (meth)acrylic polymer having a hydroxyl group can be obtained by polymerizing a monomer composition containing a (meth)acrylic acid alkyl ester, a hydroxyl group-containing monomer, and any other monomer component copolymerizable with the (meth)acrylic acid alkyl ester by any suitable polymerization method.

[0083] As described above, the base polymer of the pressure-sensitive adhesive composition is a polymer obtainable, for example, by reacting the above-mentioned hydroxyl-containing polymer with a monomer composition containing a monomer having an isocyanate group and a functional group containing a carbon-carbon unsaturated double bond. The reaction of the hydroxyl group of the hydroxyl-containing polymer with the isocyanate group of the monomer having an isocyanate group and a functional group containing a carbon-carbon unsaturated double bond results in a base polymer having an introduced carbon-carbon unsaturated double bond. The use of this base polymer makes it possible to provide a pressure-sensitive adhesive composition that has excellent irregularity-filling properties and adhesive properties, and that can prevent adhesive residue on the adherend upon peeling.

[0084] Examples of monomers having a functional group containing a carbon-carbon unsaturated double bond and an isocyanate group include monomers having an acryloyl group or a methacryloyl group and an isocyanate group, such as 2-(2-methacryloyloxyethyloxy)ethyl isocyanate, 2-isocyanate ethyl acrylate (2-acryloyloxyethyl isocyanate), 2-isocyanate ethyl methacrylate (2-methacryloyloxyethyl isocyanate), methacryloyl isocyanate, 1,1-(bisacryloyloxymethyl)ethyl isocyanate, and m-isopropenyl-α,α-dimethylbenzyl isocyanate. These may be used alone or in combination of two or more.

[0085] The amount of the monomer having a carbon-carbon unsaturated double bond and an isocyanate group added relative to the number of moles of hydroxyl groups in the hydroxyl group-containing polymer is preferably 10 mol% to 90 mol%, more preferably 30 mol% to 85 mol%, and even more preferably 50 mol% to 80 mol%. When the amount of the monomer having a carbon-carbon unsaturated double bond and an isocyanate group added is within the above range, the pressure-sensitive adhesive composition can be well cured by irradiation with active energy rays, and a pressure-sensitive adhesive composition with excellent releasability can be provided. When the amount of the monomer having a carbon-carbon unsaturated double bond and an isocyanate group added exceeds 90 mol%, the number of reaction sites with the crosslinking agent decreases, and a sufficient crosslinking effect may not be obtained.

[0086] Furthermore, for example, the monomers constituting the (meth)acrylic polymer can be roughly divided into hydrophilic monomers, hydrophobic monomers, and monomers other than the hydrophilic and hydrophobic monomers.

[0087] As the hydrophilic monomer, any appropriate monomer having a polar group can be used. Specifically, carboxyl group-containing monomers such as acrylic acid, methacrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; acid anhydride monomers such as maleic anhydride and itanoic anhydride; 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, and 1-hydroxypropyl (meth)acrylate; Hydroxyl group-containing monomers such as 0-hydroxydecyl, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl methacrylate; sulfonic acid group-containing monomers such as styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate; (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methylolpropane (meth)acrylamide, and acryloylmorpholine; (meth)acrylic acid aminoalkyl monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; and (meth)methoxy acrylate. alkoxyalkyl (meth)acrylate monomers such as ethyl, and ethoxyethyl (meth)acrylate; maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; itaconimide monomers such as N-methylitaconimide, N-ethylitaconimide, N-butylitaconimide, N-octylitaconimide, N-2-ethylhexylitaconimide, N-cyclohexylitaconimide, and N-laurylitaconimide;succinimide-based monomers such as N-(meth)acryloyloxymethylene succinimide, N-(meth)acryloyl-6-oxyhexamethylene succinimide, and N-(meth)acryloyl-8-oxyoctamethylene succinimide; vinyl-based monomers such as vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides, styrene, α-methylstyrene, and N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, and the like. p) Glycol-based acrylic ester monomers such as methoxyethylene glycol acrylate and methoxypolypropylene glycol (meth)acrylate; acrylic ester-based monomers having heterocycles, halogen atoms, silicon atoms, etc., such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, and silicon (meth)acrylate; and polyfunctional monomers such as hexanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate. Hydrophilic monomers that can be used include hydroxyl group-containing monomers and / or (N-substituted) amide-based monomers. Only one hydrophilic monomer may be used, or two or more may be used in combination. ;

[0088] The hydrophobic monomer may be any suitable monomer as long as it has hydrophobicity. Specific examples include vinyl alkyl or aryl ethers having an alkyl group having 9 to 30 carbon atoms, such as vinyl 2-ethylhexanoate, vinyl laurate, vinyl stearate, and stearyl vinyl ether; hexyl (meth)acrylate, heptyl (meth)acrylate, octyl (meth)acrylate, isooctyl acrylate, isononyl acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, benzyl (meth)acrylate, lauryl (meth)acrylate, oleyl (meth)acrylate, palmityl (meth)acrylate, and stearyl (meth)acrylate; unsaturated vinyl esters of (meth)acrylic acid derived from fatty acids and aliphatic alcohols; monomers derived from cholesterol; and olefin monomers such as 1-butene, 2-butene, 1-pentene, 1-hexene, 1-octene, isobutylene, and isoprene. The hydrophobic monomer may be used alone or in combination of two or more. The hydrophobic monomer used in the present invention refers to a monomer having a solubility of 0.02 g or less in 100 g of water.

[0089] The base polymer may further contain a monomer component other than the hydrophilic monomer and the hydrophobic monomer. Examples of the other monomer component include alkyl acrylates such as butyl acrylate and ethyl acrylate. The other monomer components may be used alone or in combination of two or more.

[0090] Here, when a polymer having a hydroxyl group is used, the ratio of the hydrophilic monomer other than the hydroxyl group-containing monomer to 100 mol% of the total amount of monomer components other than the hydroxyl group-containing monomer is preferably 5 to 50 mol%, more preferably 15 to 45 mol%, and even more preferably 25 to 40 mol%. When the ratio of the hydrophilic monomer other than the hydroxyl group-containing monomer to 100 mol% of the total amount of monomer components other than the hydroxyl group-containing monomer is 5 mol% or more, crosslinking points and double bond introduction points are provided to an extent that they can function. Furthermore, when the ratio of the hydrophilic monomer other than the hydroxyl group-containing monomer to 100 mol% of the total amount of monomer components other than the hydroxyl group-containing monomer is 50 mol% or less, the polarity of the adhesive is not too high, thereby maintaining water resistance and moisture resistance, and the cohesive strength is not too high, thereby maintaining adhesive strength.

[0091] The above description has focused on the case where a base polymer is obtained by reacting a monomer composition (base polymer monomer composition 1) containing a polymer having a hydroxyl group with a monomer having a carbon-carbon unsaturated double bond and an isocyanate group. However, the base polymer is not limited to this. That is, the base polymer can be prepared, for example, by reacting a polymer having a reactive functional group (first functional group) with a compound having a functional group (second functional group) capable of reacting with the first functional group to form a bond and a functional group containing a carbon-carbon unsaturated double bond, while maintaining the radiation polymerizability of the carbon-carbon unsaturated double bond. For this reason, the base polymer preferably contains a structural portion derived from the polymer having the first functional group and a structural portion derived from the compound having the second functional group and a carbon-carbon unsaturated double bond. In addition to acryloyl and methacryloyl groups, examples of functional groups containing a carbon-carbon unsaturated bond include vinyl, propenyl, and isopropenyl groups.

[0092] Examples of combinations of the first functional group and the second functional group include a carboxy group and an epoxy group, an epoxy group and a carboxy group, a carboxy group and an aziridyl group, an aziridyl group and a carboxy group, a hydroxy group and an isocyanate group, and an isocyanate group and a hydroxy group. Among these, from the viewpoint of ease of reaction tracking, a combination of a hydroxy group and an isocyanate group, and a combination of an isocyanate group and a hydroxy group are preferred. The above combinations may be one type only, or two or more types.

[0093] The base polymer can be prepared, for example, by polymerizing (copolymerizing) raw material monomers containing a monomer component having a first functional group to obtain a polymer having the first functional group, and then subjecting a compound having the second functional group and a carbon-carbon unsaturated double bond to a condensation reaction or addition reaction with the polymer while maintaining the radiation polymerizability of the carbon-carbon unsaturated double bond.

[0094] Various common solvents may be used during polymerization of the monomer components. Examples of such solvents include organic solvents such as esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; alicyclic hydrocarbons such as cyclohexane and methylcyclohexane; and ketones such as methyl ethyl ketone and methyl isobutyl ketone. One or more of the above solvents may be used.

[0095] The polymerization initiator, chain transfer agent, emulsifier, etc. used in the radical polymerization of the monomer components are not particularly limited and can be appropriately selected and used. The weight-average molecular weight of the polymer can be controlled by the amounts of the polymerization initiator and chain transfer agent used and the reaction conditions, and the amounts used are adjusted appropriately depending on the types of these.

[0096] As the polymerization initiator used for polymerizing the monomer components, a thermal polymerization initiator, a photopolymerization initiator (photoinitiator), etc. can be used depending on the type of polymerization reaction. Only one type of the polymerization initiator may be used, or two or more types may be used.

[0097] The thermal polymerization initiator is not particularly limited, and examples thereof include azo-based polymerization initiators, peroxide-based polymerization initiators, redox-based polymerization initiators, etc. The amount of the thermal polymerization initiator used is preferably 1 part by mass or less, more preferably 0.005 to 1 part by mass, and even more preferably 0.02 to 0.5 parts by mass, relative to 100 parts by mass of the total amount of all monomer components constituting the polymer having the first functional group.

[0098] As the photopolymerization initiator used for polymerization of the monomer component, any of the photopolymerization initiators exemplified below as the photopolymerization initiator contained in the pressure-sensitive adhesive composition can be used as appropriate.

[0099] The reaction between the polymer having the first functional group and the compound having the second functional group and the radiation-polymerizable functional group can be carried out, for example, by stirring in a solvent in the presence of a catalyst. Examples of the solvent include those described above. The catalyst is appropriately selected depending on the combination of the first functional group and the second functional group. The reaction temperature in the reaction is, for example, 5 to 100°C, and the reaction time is, for example, 1 to 36 hours.

[0100] The pressure-sensitive adhesive composition of this embodiment also contains a photopolymerization initiator in addition to the base polymer. Any appropriate initiator can be used as the photopolymerization initiator that can be contained in the pressure-sensitive adhesive composition. Examples of the photopolymerization initiator include acylphosphine oxide photoinitiators such as ethyl 2,4,6-trimethylbenzylphenylphosphinate and (2,4,6-trimethylbenzoyl)phenylphosphine oxide; α-ketol compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and 1-hydroxycyclohexylphenyl ketone; acetophenone compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin ether compounds such as benzoin ethyl ether, benzoin isopropyl ether, and anisoin methyl ether; and benzyl dimethyl ketal. aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; benzophenone compounds such as benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, and 2,4-diisopropylthioxanthone; camphorquinone; halogenated ketones; acylphosphonates; and α-hydroxyacetophenones such as 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropane-1. Preferably, 2,2-dimethoxy-2-phenylacetophenone and 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropane-1 can be used.The photopolymerization initiator may be used alone or in combination of two or more.

[0101] As the photopolymerization initiator, commercially available products may be used, for example, Omnirad 127D and Omnirad 651, both of which are trade names of IGM Resins.

[0102] The photopolymerization initiator can be used in any appropriate amount. The content of the photopolymerization initiator is preferably 0.5 to 20 parts by mass, more preferably 0.5 to 10 parts by mass, relative to 100 parts by mass of the base polymer. If the content of the photopolymerization initiator is less than 0.5 parts by mass, there is a risk that the composition will not cure sufficiently when irradiated with active energy rays. If the content of the photopolymerization initiator exceeds 20 parts by mass, there is a risk that the storage stability of the pressure-sensitive adhesive composition will decrease.

[0103] The PSA composition may further contain any appropriate additives, such as a crosslinking agent, a catalyst (e.g., a platinum catalyst), a tackifier, a plasticizer, a pigment, a dye, a filler, an antioxidant, a conductive material, an ultraviolet absorber, a light stabilizer, a release modifier, a softener, a surfactant, a flame retardant, and a solvent.

[0104] The pressure-sensitive adhesive composition preferably further contains a crosslinking agent. Examples of crosslinking agents include isocyanate-based crosslinking agents, epoxy-based crosslinking agents, aziridine-based crosslinking agents, and chelate-based crosslinking agents. The content of the crosslinking agent can be adjusted to any appropriate amount, but is preferably 0.5 to 20 parts by mass, more preferably 4 to 15 parts by mass, and even more preferably 6 to 12 parts by mass, relative to 100 parts by mass of the base polymer. The flexibility of the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition can be controlled by the content of the crosslinking agent. A content of 0.5 parts by mass or more is preferable because it provides an appropriate cohesive strength. A content of 20 parts by mass or less is preferable because it provides an appropriate adhesive strength.

[0105] As the crosslinking agent, an isocyanate-based crosslinking agent is preferably used. Isocyanate-based crosslinking agents are preferred because they can react with various functional groups. Particularly preferably, a crosslinking agent having three or more isocyanate groups is used. By using an isocyanate-based crosslinking agent as the crosslinking agent and setting the content of the crosslinking agent within the above range, it is possible to form a pressure-sensitive adhesive layer that has excellent releasability and significantly less adhesive residue even after heating.

[0106] Next, a description will be given of a case where a pressure-sensitive adhesive containing a base polymer and a radiation-polymerizable monomer or oligomer having a functional group such as a radiation-polymerizable carbon-carbon double bond is used. When a pressure-sensitive adhesive containing a radiation-polymerizable monomer or oligomer is used, any appropriate monomer or oligomer can be used as the radiation-polymerizable monomer or oligomer. Examples of radiation-polymerizable monomers include urethane (meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and 1,4-butanediol di(meth)acrylate. Examples of radiation-polymerizable oligomers include urethane-based oligomers, polyether-based oligomers, polyester-based oligomers, polycarbonate-based oligomers, and polybutadiene-based oligomers. The oligomer preferably has a molecular weight of about 100 to 30000. The monomer and oligomer may be used alone or in combination of two or more.

[0107] The monomer and / or oligomer may be used in any appropriate amount depending on the type of PSA used. For example, the amount is preferably 5 to 500 parts by weight, more preferably 40 to 150 parts by weight, per 100 parts by weight of the base polymer constituting the PSA.

[0108] As the base polymer contained in the PSA containing the radiation-polymerizable monomer or oligomer, an appropriate resin such as the acrylic polymer described above is used depending on the type of PSA. The PSA containing the radiation-polymerizable monomer or oligomer may also contain a polymerization initiator, a crosslinking agent, etc. as appropriate, which are the same as the components described for the PSA containing the polymer having a radiation-polymerizable functional group as the base polymer.

[0109] The pressure-sensitive adhesive layer may also contain a thermoplastic resin. Examples of thermoplastic resins include natural or synthetic rubbers such as natural rubber, polyisobutylene, polyisoprene, chloroprene rubber, butyl rubber, and nitrile butyl rubber; olefin elastomers such as ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-vinyl acetate copolymer, polybutene, and chlorinated polyethylene; styrene elastomers such as styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, and hydrogenated products thereof; polyester elastomers; polyamide elastomers; and various thermoplastic elastomers such as polyurethane elastomers. These rubber components or thermoplastic elastomer components may be used alone or in combination of two or more.

[0110] The pressure-sensitive adhesive layer can be produced, for example, by applying a pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer onto a release liner and drying the resulting pressure-sensitive adhesive composition layer, or by applying the pressure-sensitive adhesive composition onto a release liner. If necessary, the applied layer may be further dried by heating.

[0111] The thickness of the pressure-sensitive adhesive layer is not particularly limited, but from the viewpoint of exhibiting good adhesion to two-dimensional materials, it is preferably 2 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more, and from the viewpoint of forming a smooth pressure-sensitive adhesive layer, it is preferably 500 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0112] Furthermore, in the above-described separation step, when a laminate including a pressure-sensitive adhesive tape as a support layer and a two-dimensional material is separated from a first substrate, the tensile modulus of the pressure-sensitive adhesive layer in the pressure-sensitive adhesive tape in the laminate is preferably 1 MPa to 1000 MPa. Here, from the viewpoint of suppressing damage to the two-dimensional material due to deformation, the tensile modulus of the pressure-sensitive adhesive layer is preferably 1 MPa or more, more preferably 5 MPa or more, more preferably 9 MPa or more, more preferably 10 MPa or more, more preferably 20 MPa or more, and even more preferably 100 MPa or more. Furthermore, the tensile modulus of the pressure-sensitive adhesive layer is preferably 1000 MPa or less, more preferably 200 MPa or less, and even more preferably 150 MPa or less. When the tensile modulus of the pressure-sensitive adhesive layer close to the first substrate during bubble formation is 1000 MPa or less, it is easier to suppress or prevent bubbles contributing to separation from escaping from the edge of the laminate before they grow large when bubbles are formed between the first substrate and the two-dimensional material. The tensile modulus of the pressure-sensitive adhesive layer is the tensile modulus at 23°C.

[0113] Specifically, the tensile modulus of the pressure-sensitive adhesive layer can be calculated as follows: A cylindrical sample of the pressure-sensitive adhesive layer is rolled to a length of 30 mm and a diameter of 1 mm, and the sample is chucked at 10 mm above and below in the longitudinal direction and pulled at a rate of 50 mm / min. The initial tensile modulus is calculated from the slope of the stress versus strain gradient at the maximum point between 10% strain and 100% strain, and measured using a tensile tester; this is the tensile modulus of the pressure-sensitive adhesive layer.

[0114] Furthermore, the tensile modulus of elasticity of the adhesive layer in the adhesive tape in the laminate separated from the first substrate can be considered to be substantially the same as the tensile modulus of elasticity of the adhesive layer in the adhesive tape in the laminate at the time of bubble formation.

[0115] Furthermore, when the pressure-sensitive adhesive layer is a curable pressure-sensitive adhesive layer, the tensile modulus of elasticity of the pressure-sensitive adhesive layer after curing is preferably within the above-mentioned range.

[0116] Specifically, the tensile modulus of the pressure-sensitive adhesive layer after curing can be calculated as follows: ２A cylindrical sample is irradiated with ultraviolet light and rolled to a length of 30 mm and a diameter of 1 mm, and chucked at 10 mm above and below the length, and pulled at a rate of 50 mm / min. The initial tensile modulus is calculated from the slope of the stress versus strain gradient at a maximum point between 10% strain and 100% strain, and measured using a tensile tester. This is the tensile modulus of the pressure-sensitive adhesive layer after curing. If the pressure-sensitive adhesive layer after ultraviolet irradiation is brittle and easily breaks when rolled to a length of 30 mm and a diameter of 1 mm, it can be wound without breakage by masking 5% or less of the winding direction at the start of winding to prevent ultraviolet irradiation.

[0117] Examples of substrates constituting the pressure-sensitive adhesive tape include those made of resin, nonwoven fabric, woven fabric, metal foil, paper, etc. Among these, substrates made of resin (resin substrates) are preferred from the viewpoints of smoothness, ease of handling, cost, etc.

[0118] Specific examples of resins constituting the substrate include polyester-based resins such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), and polybutylene naphthalate (PBN), polyolefin-based resins such as ethylene-vinyl acetate copolymer (EVA), ethylene-methyl methacrylate copolymer, polyethylene, polypropylene, and ethylene-propylene copolymer, polyurethane-based resins, polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinyl acetate, polyamide, polyimide, celluloses, fluorine-based resins, polyethers, polystyrene-based resins such as polystyrene, polycarbonate, and polyethersulfone. Among these, from the viewpoint of tensile modulus that provides flexibility, ethylene-vinyl acetate copolymer (EVA), polyolefin-based resins, and polyurethane-based resins are preferred, and ethylene-vinyl acetate copolymer (EVA) is particularly preferred.

[0119] The thickness of the substrate can be set to any appropriate value. The thickness of the substrate is preferably 10 μm to 300 μm, more preferably 50 μm to 150 μm. The substrate may be an unstretched film, or may be one that has been subjected to uniaxial or biaxial stretching treatment as necessary. Furthermore, when the pressure-sensitive adhesive layer 12 is an active energy ray-curable pressure-sensitive adhesive layer, the substrate 11 preferably has a property of transmitting active energy rays such as ultraviolet rays.

[0120] The tensile modulus of the substrate is preferably 10 MPa to 4000 MPa. Here, from the viewpoint of ease of handling of the pressure-sensitive adhesive tape, the tensile modulus of the substrate is preferably 10 MPa or more, more preferably 30 MPa or more, and even more preferably 50 MPa or more. Furthermore, the tensile modulus of the substrate is preferably 4000 MPa or less, more preferably 1000 MPa or less, and even more preferably 100 MPa or less. By adjusting the tensile modulus of the relatively hard substrate, among the components constituting the pressure-sensitive adhesive tape, to 4000 MPa or less, it is easy to adjust the tensile modulus of the pressure-sensitive adhesive tape as a support layer to 3000 MPa or less. As a result, when bubbles are formed between the first substrate and the two-dimensional material, it is easy to suppress or prevent the bubbles that contribute to separation from escaping from the edge of the laminate including the pressure-sensitive adhesive tape and the two-dimensional material before they grow large. The tensile modulus of the substrate is the tensile modulus at 23°C.

[0121] The tensile modulus of the substrate can be calculated specifically as follows. A sample of the substrate with a width of 10 mm and a length of 20 mm is prepared, chucked at 5 mm above and below the longitudinal direction with a chuck distance of 10 mm, and pulled at a speed of 50 mm / min. The initial tensile modulus is calculated from the slope at the point where the slope of the stress versus strain is maximum between 10% strain and 100% strain, and measured using a tensile tester. This is the tensile modulus of the substrate. When the tensile modulus has anisotropy that varies depending on the pulling direction, the average of the tensile modulus when pulled in at least two orthogonal directions in the plane is used. For example, the average of the values ​​measured in two orthogonal directions in the plane (MD and TD) is used as the long side direction (length direction).

[0122] (Method for producing pressure-sensitive adhesive tape) The pressure-sensitive adhesive tape can be produced by any appropriate method. In one embodiment, the pressure-sensitive adhesive tape can be produced by forming a pressure-sensitive adhesive layer on a substrate. The pressure-sensitive adhesive layer may be formed by coating the substrate with the composition that forms the pressure-sensitive adhesive layer, or the pressure-sensitive adhesive layer may be formed on any appropriate release liner and then transferred to the substrate. As the coating method, various methods can be used, such as bar coater coating, air knife coating, gravure coating, gravure reverse coating, reverse roll coating, lip coating, die coating, dip coating, offset printing, flexographic printing, and screen printing.

[0123] As described above, the present specification describes the following: (1) A method for manufacturing a laminate, comprising: forming bubbles between a first substrate and a two-dimensional material with a support layer attached to the first substrate; and separating a laminate including the support layer and the two-dimensional material from the first substrate by forming the bubbles or by pulling at least one of the support layer and the first substrate after forming the bubbles, wherein the support layer is removably removable, and the laminate has a tensile modulus of 10 to 3000 MPa at 23°C under the following measurement conditions: (Measurement conditions for the tensile modulus of the laminate) A sample of the laminate, 10 mm wide and 20 mm long, is chucked at 5 mm above and below in the longitudinal direction, and pulled at a rate of 50 mm / min. The initial tensile modulus is calculated from the slope of the stress-to-strain gradient at the point where the gradient is greatest between 10% strain and 100% strain. (2) The method for producing a laminate according to (1), wherein the adhesive strength of the support layer to a silicon wafer at 23°C is 0.001 N / 20 mm to 2.0 N / 20 mm when subjected to a 180° peel at a tensile speed of 300 mm / min. (3) The method for producing a laminate according to (1) or (2), wherein the support layer is a pressure-sensitive adhesive tape comprising a pressure-sensitive adhesive layer and a substrate. (4) The method for producing a laminate according to (3), wherein the tensile modulus of the substrate at 23°C is 10 to 4000 MPa under the following measurement conditions. (Measurement conditions for tensile modulus of substrate) A sample of the substrate having a width of 10 mm and a length of 20 mm is chucked at 5 mm above and below in the longitudinal direction, and pulled at a speed of 50 mm / min. The initial tensile modulus is calculated from the slope of the stress-to-strain gradient at the point where the slope is maximum between 10% strain and 100% strain. (5) The method for producing a laminate according to (3) or (4), wherein the pressure-sensitive adhesive layer has a tensile modulus of elasticity at 23° C. of 1 to 1000 MPa measured under the following conditions:(Conditions for measuring the tensile modulus of the pressure-sensitive adhesive layer) A cylindrical sample of the pressure-sensitive adhesive layer is rolled to a length of 30 mm and a diameter of 1 mm, and the sample is chucked at 10 mm above and below in the longitudinal direction and pulled at a rate of 50 mm / min. The initial tensile modulus is calculated from the slope of the stress-to-strain curve at a maximum point between 10% strain and 100% strain when the sample is pulled. (6) A method for producing a laminate according to any one of (3) to (5), wherein the pressure-sensitive adhesive layer is a pressure-sensitive adhesive layer that hardens when supplied with a predetermined energy or substance. (7) A method for producing a laminate according to (6), wherein the pressure-sensitive adhesive layer has a tensile modulus of 1 to 1,000 MPa at 23°C after hardening under the following measurement conditions. (Conditions for measuring the tensile modulus of the pressure-sensitive adhesive layer after hardening) An integrated light dose of 450 mJ / cm is applied to the pressure-sensitive adhesive layer. ２ The initial tensile modulus of the pressure-sensitive adhesive layer is determined by calculating the initial tensile modulus from the slope of the stress-to-strain curve at a maximum point between 10% strain and 100% strain when a cylindrical sample is irradiated with ultraviolet light and rolled to a length of 30 mm and a diameter of 1 mm, chucked at 10 mm above and below the length, and pulled at a rate of 50 mm / min. (8) The method for manufacturing a laminate according to (6) or (7), which includes a step of supplying a predetermined energy or substance to harden the pressure-sensitive adhesive layer before the step of forming bubbles. (9) A method for manufacturing a two-dimensional material laminate according to any one of (1) to (8), which includes a step of placing the laminate obtained by the method for manufacturing a laminate according to any one of (1) to (8) on a second substrate so that the surface of the laminate facing the two-dimensional material is in contact with the second substrate, and a step of transferring the two-dimensional material onto the second substrate by peeling off the support layer to obtain a two-dimensional material laminate including the second substrate and the two-dimensional material. (10) A 100 mm ２ (11) The two-dimensional material according to (10), having a transfer rate of 70% or more. (12) The two-dimensional material according to (10) or (11), having a contamination level of -30% or more and 10% or less. (13) The two-dimensional material comprises graphene and has a mobility of 2000 cm ２ The two-dimensional material according to any one of (10) to (12), wherein the surface tension is 1 / V / s or more.

[0124] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples in any way.

[0125] <Adhesive Sheet 1> A monomer composition (solids concentration: 40%) was prepared by mixing three types of monomers: 71.2 g of 2-ethylhexyl acrylate (2EHA) (60 mol % of the total amount of monomers not containing a hydroxyl group), 36.4 g of acryloylmorpholine (ACMO) (40 mol % of the total amount of monomers not containing a hydroxyl group), and 20.4 g of 4-hydroxybutyl acrylate (4HBA) (amount equivalent to 22 mol % when the total amount of monomers not containing a hydroxyl group was taken as 100 mol %), 0.3 mass % of a polymerization initiator (manufactured by NOF Corporation, trade name: Nyper (registered trademark) BW) relative to the total mass of the monomers, and a solvent (ethyl acetate). The monomer composition was placed in a 1 L round-bottom separable flask equipped with a separable cover, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade. The mixture was then purged with nitrogen at room temperature for 2 hours while stirring. The mixture was then polymerized at 61°C for 8 hours under a nitrogen inflow to obtain a resin solution. To the resulting resin solution was added 12.0 g (equivalent to 12 mol% when the total amount of hydroxyl-free monomers was taken as 100 mol%) of a compound (manufactured by Showa Denko K.K., trade name "Karenz MOI") that introduces a carbon-carbon unsaturated double bond. Furthermore, 0.063 parts by mass of dibutyltin IV dilaurate (manufactured by Wako Pure Chemical Industries, Ltd.) was added per 100 parts by mass of resin solids, and a solvent (ethyl acetate) was added as appropriate to adjust the solids concentration to 15%. The mixture was then stirred at 50°C for 24 hours under an air atmosphere to obtain a pressure-sensitive adhesive solution A (pressure-sensitive adhesive composition) containing the acrylic polymer A. Next, 12 parts by mass of a polyisocyanate compound (trade name "Takenate D-101E", manufactured by Mitsui Chemicals, Inc.) and 4 parts by mass of a photopolymerization initiator (trade name "Omnirad 651", manufactured by IGM Resins) were added to the pressure-sensitive adhesive solution A, relative to 100 parts by mass of the acrylic polymer A, to prepare a pressure-sensitive adhesive solution A'. The pressure-sensitive adhesive solution A' prepared above was applied to the silicone-treated surface of a PET release liner and heated at 120°C for 2 minutes to crosslink the adhesive, forming a pressure-sensitive adhesive layer with a thickness of 15 μm. Next, a 115 μm-thick ethylene-vinyl acetate copolymer (EVA) film was laminated to the pressure-sensitive adhesive layer surface. After storage at 50°C for 24 hours, the resulting sheet was designated as pressure-sensitive adhesive sheet 1.

[0126] <Adhesive sheet 2> Adhesive sheet 2 was prepared in the same manner as Adhesive sheet 1, except that 2EHA was changed to 90 mol % of the total amount of monomers not containing a hydroxyl group, ACMO was changed to 10 mol % of the total amount of monomers not containing a hydroxyl group, and KarenzMOI was changed to an amount equivalent to 18 mol % when the total amount of monomers not containing a hydroxyl group was taken as 100 mol %. The resulting sheet was designated Adhesive sheet 2.

[0127] <Adhesive Sheet 3> Adhesive sheet 3 was obtained in the same manner as adhesive sheet 1, except that the EVA film in adhesive sheet 1 was replaced with a polyethylene terephthalate (PET) film having a thickness of 50 μm.

[0128] <Adhesive Sheet 4> A monomer composition (solids concentration: 40%) was prepared by mixing three types of monomers: 60.0 g of 2-ethylhexyl acrylate (2EHA), 65.4 g of methyl acrylate (MA), and 6.3 g of acrylic acid (AA), 0.3 mass% of a polymerization initiator (manufactured by NOF Corporation, product name: Nyper (registered trademark) BW) based on the total mass of the monomers, and a solvent (ethyl acetate). The monomer composition was placed in a 1 L round-bottom separable flask and placed in a polymerization experimental apparatus equipped with a separable cover, a separatory funnel, a thermometer, a nitrogen inlet tube, a Liebig condenser, a vacuum seal, a stirring rod, and a stirring blade. The atmosphere was replaced with nitrogen at room temperature for 2 hours while stirring. The mixture was then polymerized at 61°C for 8 hours while stirring under a nitrogen inflow, yielding a pressure-sensitive adhesive solution B (pressure-sensitive adhesive composition) containing an acrylic polymer B. Next, to 100 parts by mass of acrylic polymer B, 100 parts by mass of dipentaerythritol hexaacrylate (DPHA manufactured by Nippon Kayaku Co., Ltd.), 3 parts by mass of a polyisocyanate compound (trade name "Takenate D-101E" manufactured by Mitsui Chemicals, Inc.), and 3 parts by mass of a photopolymerization initiator (trade name "Omnirad 651" manufactured by IGM Resins) were added to prepare adhesive solution B'. The adhesive solution B' prepared above was applied to the silicone-treated surface of a PET release liner and heated at 120 ° C. for 2 minutes to crosslink, forming a 5 μm thick adhesive layer. Next, a 188 μm thick PET film was bonded to the adhesive layer surface. After that, the sheet was stored at 50 ° C. for 24 hours, and the resulting sheet was designated adhesive sheet 4.

[0129] <Adhesive sheet 5> The adhesive sheet 5 was produced in the same manner as the adhesive sheet 4, except that the 188 μm thick PET film in the adhesive sheet 4 was changed to a 115 μm thick ethylene-vinyl acetate copolymer (EVA) film.

[0130] <Adhesive Sheet 6> Adhesive sheet 6 was produced in the same manner as Adhesive Sheet 1, except that in Adhesive Sheet 1, 2EHA was changed to 75 mol% of the total amount of monomers not containing a hydroxyl group, ACMO was changed to 25 mol% of the total amount of monomers not containing a hydroxyl group, Takenate D-101E was changed to 4 parts by mass, and Omnirad 651 was changed to 3 parts by mass.

[0131] <Formation of an epitaxial metal film on the surface of a single crystal substrate by sputtering> Sapphire (α-Al) purchased from Adamant Namiki Precision Jewel Co., Ltd. was used as a single crystal substrate. ２ O ３ The c-plane (0001) of the single crystal substrate was used. The single crystal substrate was placed in the chamber of an RF magnetron sputtering device (Shibaura Mechatronics CFS-4ES), and Cu metal was sputtered onto the entire surface of the single crystal substrate (Ar atmosphere, standard vacuum of 0.6 Pa). This resulted in the epitaxial deposition of a Cu film with a thickness of 1000 nm, yielding a Cu / sapphire substrate.

[0132] <Graphene CVD deposition> A quartz tube (substrate size: 200 mm) was set in a ceramic tube furnace manufactured by Asahi Rika Seisakusho. ２ In the case of an inner diameter of 26 mm and a board size of 7854 mm ２ The Cu / sapphire substrate was placed inside a chamber (inner diameter 140 mm for a 4-inch wafer) as a substrate for graphene deposition. The Cu / sapphire substrate had a substrate size of 10 mm x 20 mm or 7854 mm. ２ A 4-inch wafer was used. The temperature was then raised to a predetermined temperature (1000-1075°C) under atmospheric pressure while flowing argon and hydrogen. After reaching the predetermined temperature, the temperature was maintained under the same conditions for 0-3 hours to reduce and smooth the Cu surface. Then, 10-200 ppm of methane was added, and a chemical vapor reaction was carried out for 90 minutes. After the reaction, the substrate was cooled to room temperature (23°C), and the Cu / sapphire substrate (first stack: stack 1-1) on which single-layer graphene had been produced was removed from the quartz tube. Through this reaction, a continuous single-layer graphene film covering the entire Cu surface was formed on the Cu surface. Furthermore, 90% or more of the area of ​​the formed graphene was single-layer.

[0133] <CVD deposition of h-BN> A 20 μm thick Fe—Ni alloy foil (manufactured by Nilaco Corporation, mainly composed of Fe (approximately 64%) and Ni (32%)) was placed inside an alumina tube (inner diameter 24 mm) set in a ceramic tubular furnace manufactured by Asahi Rika Seisakusho, as a substrate for deposition of h-BN. The Fe—Ni alloy foil used had a substrate size of 20 mm × 20 mm. The inside of the tube was then conditioned to a reduced pressure hydrogen atmosphere (10 to 100 Pa), and the temperature was raised to a predetermined temperature (1000 to 1100°C). After reaching the predetermined temperature, the alloy foil was maintained under the same conditions for 0 to 3 hours to reduce and smooth the surface. Subsequently, the temperature of the tubular furnace was raised to 1100 to 1200°C, and borazine (B ３ N ３ H ６ ) vaporized gas was introduced at a partial pressure of 0.1 to 1 Pa. The sample was slowly cooled to 700°C (cooling rate: 5°C / min) to promote uniform precipitation of h-BN, and then rapidly cooled to room temperature (23°C). This reaction resulted in the formation of a continuous h-BN film covering the entire surface of the Fe—Ni alloy foil. In this way, an Fe—Ni alloy foil (first laminate: laminate 1-2) with multilayer h-BN was obtained.

[0134] Example 1 Area: 200 mm ２ The adhesive sheet 1 was attached to the graphene side of the first laminate (laminate 1-1) using a roller (pressure of 2 kg / 10 mm), and the laminate was autoclaved at 50°C and 5 atmospheres for 30 minutes, and then allowed to stand at room temperature and normal pressure for 30 minutes to produce a second laminate. A portion of the adhesive sheet in the outer periphery of the substrate in the second laminate was trimmed with a cutter knife to remove a 5 mm ２ A Cu / graphene surface exposed portion of about 450 mJ / cm was produced from the substrate side of the adhesive sheet 1 using a UV irradiator (UM-810 manufactured by Nitto Seiki Co., Ltd.). ２The UV treatment was performed with an irradiation dose of 1000 kJ / cm. The exposed Cu / graphene surface of the second laminate (substrate / graphene / adhesive sheet 1) was clamped with an electrode clip to form a working electrode, a Pt electrode as a counter electrode, and an Ag / AgCl electrode as a reference electrode. Each was immersed in an acrylic water tank filled with 1 M aqueous sodium hydroxide solution, and a DC voltage of 4 V was applied using a potentiostat (Vertex 10A, manufactured by IVIUM). After voltage application, gas (bubbles) were generated by electrolysis at the interface between the Cu surface and the graphene, and the graphene / adhesive sheet 1 laminate (third laminate) was separated from the Cu / sapphire substrate. The graphene / adhesive sheet 1 laminate (third laminate) was immersed in ion-exchanged water for cleaning, and then separated from a silicon substrate with an oxide film (SUMCO silicon (crystal plane (100)), size 200 mm). ２ The graphene was attached to a silicon substrate (20 mm x 10 mm, surface thermally oxidized, oxide film thickness 300 nm, hereinafter simply referred to as "silicon substrate") using a roller (pressure of 2 kg / 10 mm) with water, left to stand at room temperature for 24 hours, and then heat-treated at 90°C for 3 hours to obtain a fourth laminate. ２ ) side. The silicon substrate in the fourth laminate was fixed, and the pressure-sensitive adhesive sheet 1 was peeled off at a peel angle of 180 degrees and a peel speed of 300 mm / min using a tensile tester (VPA-H200F, manufactured by Kyowa Interface Science Co., Ltd.), thereby transferring the graphene to the silicon substrate, and a laminate of the silicon substrate and graphene in Example 1 (fifth laminate) was obtained. The fifth laminate is also referred to as a two-dimensional material laminate.

[0135] Example 2 A laminate (fifth laminate) of a silicon substrate and graphene in Example 2 was obtained in the same manner as in Example 1, except that UV irradiation was not performed.

[0136] Example 3 A laminate of a silicon substrate and graphene in Example 3 (fifth laminate) was obtained in the same manner as in Example 1, except that UV irradiation was not performed before separating the third laminate from the Cu substrate, but was performed immediately before peeling off the adhesive sheet 1 from the silicon substrate.

[0137] Example 4 A laminate of a silicon substrate and graphene in Example 4 (fifth laminate) was obtained in the same manner as in Example 1, except that Adhesive Sheet 2 was used instead of Adhesive Sheet 1 as the adhesive sheet in Example 1.

[0138] Example 5 A laminate of a silicon substrate and graphene in Example 5 (fifth laminate) was obtained in the same manner as in Example 1, except that Adhesive Sheet 3 was used instead of Adhesive Sheet 1 as the adhesive sheet in Example 1.

[0139] Example 6 In Example 1, the area of ​​the first laminate was 7854 mm ２ (= 4-inch wafer), the size of the silicon substrate to be transferred is 12100 mm ２ A laminate of a silicon substrate and graphene in Example 6 (fifth laminate) was obtained in the same manner as in Example 1, except that the dimensions of the substrate were changed to (110 mm x 110 mm).

[0140] Example 7 A laminate of a silicon substrate and graphene in Example 7 (fifth laminate) was obtained in the same manner as in Example 1, except that Adhesive Sheet 5 was used instead of Adhesive Sheet 1 as the adhesive sheet in Example 1.

[0141] Example 8: Area 200 mm ２ An adhesive sheet 6 was attached to the h-BN side of the first laminate (laminate 1-2) using a roller (pressure of 2 kg / 10 mm), autoclaved at 50°C and 5 atmospheres for 30 minutes, and then left to stand at room temperature and normal pressure for 30 minutes to produce a second laminate. A portion of the adhesive sheet in the outer periphery of the substrate in the second laminate was trimmed with a cutter knife to remove a 5 mm ２ A bare surface of Fe—Ni / h-BN was prepared by irradiating the adhesive sheet 6 with a UV irradiator (UM-810 manufactured by Nitto Seiki Co., Ltd.) at 450 mJ / cm from the substrate side. ２The UV treatment was performed with an irradiation dose of 1000 kJ / cm. The exposed portion of the Fe-Ni / h-BN surface of the second laminate (substrate / graphene / adhesive sheet 6) was clamped with an electrode clip to form a working electrode, a Pt electrode as the counter electrode, and an Ag / AgCl electrode as the reference electrode. Each was immersed in an acrylic water tank filled with a 1 M aqueous solution of sodium hydroxide, and a DC voltage of 4 V was applied using a potentiostat (Vertex 10A manufactured by IVIUM). After voltage application, gas (bubbles) were generated by electrolysis at the interface between the Fe-Ni surface and the h-BN, and the h-BN / adhesive sheet 6 laminate (third laminate) was separated from the Fe-Ni alloy foil. The h-BN / adhesive sheet 6 laminate (third laminate) was immersed in ion-exchanged water for cleaning, and then attached to a silicon substrate with an oxide film using a roller (2 kg / 10 mm pressure), left to stand at room temperature for 24 hours, and then heat-treated at 90°C for 3 hours to obtain a fourth laminate. The h-BN was then attached to the oxide film (SiO ２ ) side. The silicon substrate in the fourth laminate was fixed, and the adhesive sheet 6 was peeled off at a peel angle of 180 degrees and a peel speed of 300 mm / min using a tensile tester (VPA-H200F, manufactured by Kyowa Interface Science Co., Ltd.), thereby transferring the h-BN to the silicon substrate, and a laminate of the silicon substrate and h-BN in Example 8 (fifth laminate) was obtained. The fifth laminate is also referred to as a two-dimensional material laminate.

[0142] Comparative Example 1 A Cu / sapphire substrate (first laminate: laminate 1-1) on which single-layer graphene was formed was prepared in the same manner as in Example 1. Subsequently, a toluene solution of polymethyl methacrylate (PMMA) was used to coat the surface of the graphene on Cu using a spin coater instead of adhesive sheet 1, and a portion of the PMMA in the outer periphery of the substrate was trimmed by solvent washing in the same manner as in Example 1 to form a 5 mm ２A portion with an exposed Cu / graphene surface of approximately 1000 nm was produced. The exposed Cu / graphene surface of the laminate (substrate / graphene / PMMA) was clamped with an electrode clip, and the graphene / PMMA laminate was separated from the Cu substrate by applying a voltage as in Example 1. The graphene / PMMA laminate floating on the surface of the 1 M aqueous sodium hydroxide solution was scooped up along with the solution using a watch glass and transferred to a separately prepared Petri dish containing ion-exchanged water. The graphene / PMMA laminate was washed by repeating the process of scooping up with the watch glass and transferring into ion-exchanged water 10 times. After repeated washing, the graphene / PMMA laminate floating in the ion-exchanged water was scooped up using the same silicon substrate with an oxide film as used in Example 1, left at room temperature for 24 hours, and then heat-treated at 90°C for 3 hours to obtain a laminate (silicon substrate / graphene / PMMA). The PMMA could not be peeled off like an adhesive sheet, and a laminate of silicon substrate and graphene was not obtained.

[0143] <Comparative Example 2> A laminate of a silicon substrate and graphene in Comparative Example 2 (fifth laminate) was obtained in the same manner as in Example 1, except that Adhesive sheet 4 was used instead of Adhesive sheet 1 as the adhesive sheet in Example 1.

[0144] Comparative Example 3 A laminate of a silicon substrate and graphene in Comparative Example 3 (a fifth laminate) was obtained in the same manner as in Example 1, except that UV irradiation was not performed, and further, when separating the graphene / adhesive sheet 1 laminate (a third laminate) from the Cu surface, the adhesive sheet 1 was peeled off in the atmosphere using a tensile tester (VPA-H200F, manufactured by Kyowa Interface Science Co., Ltd.) at a peel angle of 180 degrees and a peel speed of 300 mm / min.

[0145] Comparative Example 4 A laminate of a silicon substrate and graphene in Comparative Example 4 (fifth laminate) was obtained in the same manner as in Example 3, except that, when separating the graphene / adhesive sheet 1 laminate (third laminate) from the Cu surface in Example 3, the adhesive sheet 1 was peeled off in the atmosphere at a peel angle of 180 degrees and a peel speed of 300 mm / min.

[0146] <Tensile Modulus> A 10 mm wide x 20 mm long sample of the pressure-sensitive adhesive sheet / graphene laminate (third laminate) obtained at an intermediate stage in Examples 1 to 8 and Comparative Examples 2 to 4 (Example 6 is a sample cut out from a 4-inch wafer with a central width of 10 mm x length of 20 mm) was chucked at 5 mm above and below in the longitudinal direction with a chuck distance of 10 mm, and pulled at a speed of 50 mm / min. The initial tensile modulus was calculated from the slope at the point where the slope of the stress with respect to strain was maximum between 10% strain and 100% strain when the sample was measured using a tensile tester (AUTOGRAPH AGS-X, manufactured by Shimadzu Corporation), and this was used as the tensile modulus of the laminate (third laminate). Note that since the PMMA / graphene laminate of Comparative Example 1 is a thin layer and difficult to handle, a 50 μm thick cast film of PMMA was separately prepared and measured in the same manner as above to calculate the tensile modulus. The tensile modulus of the substrate was measured and calculated in the same manner as above for the substrate alone prepared during the production of PSA sheets 1 to 6. The tensile modulus of the pressure-sensitive adhesive layer was measured and calculated in the same manner as above for the pressure-sensitive adhesive layer obtained during the production of PSA sheets 1 to 6 before bonding to the substrate, using a cylindrical sample of 30 mm in length and 1 mm in diameter, with chucks at 10 mm above and below in the length direction for both the cases with and without UV irradiation. The UV treatment was carried out using a UV irradiator (UM-810 manufactured by Nitto Seiki Co., Ltd.) at 450 mJ / cm from the substrate side of the pressure-sensitive adhesive sheet. ２ The UV treatment was carried out before the pressure-sensitive adhesive layer was rolled into a cylindrical sample. The tensile modulus values ​​were measured at 23°C.

[0147] <Removability of Support Layer> The pressure-sensitive adhesive sheets used in Examples 1 to 8 and Comparative Examples 2 to 4 were each cut to a width of 20 mm and a length of 10 cm, and the release liner was peeled off and removed. Subsequently, the pressure-sensitive adhesive sheet of each example was attached to a silicon wafer (a 4-inch silicon mirror wafer) by pressing it back and forth with a 2 kg roller once, and then left to stand for 30 minutes. Except for Example 2 and Comparative Example 3, the pressure-sensitive adhesive sheet was irradiated with 450 mJ / cm from the substrate side of the pressure-sensitive adhesive sheet using a UV irradiator (UM-810, manufactured by Nitto Seiki Co., Ltd.). ２UV irradiation was performed at an irradiation dose of 180°. Using a tensile tester (VPA-H200F, manufactured by Kyowa Interface Science Co., Ltd.), the peel force when peeled at a peel angle of 180° and a peel speed of 300 mm / min was measured as removability A (180° peel force from silicon wafer) (N / 20 mm). The measurement temperature was 23°C. Furthermore, in Examples 1 to 8 and Comparative Examples 2 to 4, the peel force when actually peeling the pressure-sensitive adhesive sheet from the silicon substrate was measured as removability B (180° peel force when releasing two-dimensional material from silicon substrate) (N / 10 mm). The measurement temperature was 23°C.

[0148] <Transfer rate> The transfer rate of the laminate of silicon substrate and graphene or the laminate of silicon substrate and h-BN (fifth laminate) obtained in Examples 1 to 8 and Comparative Examples 2 to 4 was 1 / 3 of the transfer rate of the substrate (oxide film (SiO ２ The image of graphene or h-BN remaining on the surface of the substrate (side 1) was obtained as a digital image using an optical microscope (VHX-8000, manufactured by Keyence Corporation). The digital image was observed at a magnification of 500 times using an objective lens and measured 10 mm in length × 20 mm in width (7854 mm in Example 6). ２ Digital images were taken at nine locations on the graphene or h-BN side of the laminate (4-inch wafer size). Specifically, the center of the substrate was designated as point E, and two points 6.5 mm (50 mm in Example 6) away from point E on the left and right were designated as points D and F. Furthermore, points 2.5 mm (50 mm in Example 6) away from point D on the top and bottom were designated as points A and G. Similarly, points 2.5 mm (50 mm in Example 6) away from point E on the top and bottom were designated as points B and H, respectively, and points 2.5 mm (50 mm in Example 6) away from point F on the top and bottom were designated as points C and I, respectively. A 500 μm × 300 μm area was used to perform RGB separation and binarization analysis of each component image using the software "imageJ" from the digital images taken for each of points A to I, and the area ratio of graphene or h-BN in the corresponding digital image was calculated as a percentage. The average area ratio of graphene or h-BN in the digital images of the nine points A to I was taken as the transfer rate (%).

[0149] <Low Contamination (Contamination Amount)> The laminates of silicon substrate and graphene or h-BN obtained in Examples 1 to 8 and Comparative Examples 2 to 4 were subjected to ESCA analysis. The contamination amount was defined as the increase in the carbon element amount (atomic %) calculated by ESCA analysis relative to the carbon element amount (atomic %) measured for the graphene laminate or h-BN laminate on the Cu surface or Fe—Ni alloy foil surface before transfer. The carbon amount was determined as the elemental ratio (atomic %) of carbon to the total amount of the five elements by narrow scan analysis of the five elements carbon, oxygen, nitrogen, silicon, and copper by X-ray photoelectron spectroscopy (ESCA) on the surface of the target substrate. The analytical device used was a "Quantum 2000" manufactured by ULVAC PHI. The analytical device and measurement conditions used to measure the carbon amount are shown below. Apparatus: Quantum 2000 manufactured by ULVAC PHI X-ray source: Monochrome AlKα X-ray setting: 200 μmφ [15 kV, 30 W] Bond energy correction: Peak due to C—C bond was corrected to 285.0 eV Charge neutralization conditions: Neutralization gun and Ar ion gun (neutralization mode) used in combination Samples with a contamination level of −30% or more and 10% or less were evaluated as having low contamination.

[0150] <Mobility> For each of the laminates (fifth laminates) of silicon substrate and graphene obtained in Examples 1 to 7 and Comparative Examples 2 to 4, a resist (AZ5214-E, manufactured by Clariant) was formed on the graphene by spin casting (300 rpm, 5 seconds, followed by 3300 rpm, 30 seconds). Note that the processes from resist coating to pattern exposure and removal of the unexposed portions of the resist were carried out in a UV-blocking environment. Subsequently, the laminate was baked on a hot plate at 90°C for 1 minute to remove excess solvent.

[0151] The laminate on which the resist was formed was set in an exposure device (PALET DDB-701, manufactured by Neoark Corporation) and irradiated with light at 60 mW / cm to form a pattern in the shape of the transistor channel. ２ The image was exposed to light for 1.1 seconds.

[0152] To carry out the subsequent development process, the exposed laminate was immersed in an NMD-3 (2.38%, organic alkaline aqueous solution, manufactured by Tokyo Ohka Kogyo Co., Ltd.) solution for 100 seconds while gently moving it, and then immersed in water to wash off the NMD-3, thereby removing the unexposed portions of the resist.

[0153] The fifth stack, on whose surface the transistor channel-shaped pattern remained, was subjected to an ashing treatment (Yamato Scientific, PR-500) to remove the graphene in the areas not covered by the pattern.The pattern was then removed with acetone to obtain the graphene channel shape.

[0154] After the channel processing was completed, a resist film was again formed on the fifth stack by spin casting, and an exposure device was used to form a pattern so that the resist covered all areas except for the areas where the electrodes on both ends of the graphene channel were planned, and a development process was then performed.

[0155] On the fifth stack in which the graphene channel had been processed and the area other than the area intended for the electrode was covered with resist, a vacuum deposition apparatus (KB-750 manufactured by Kenix) was used to deposit 10 －４ Under a reduced pressure of 10 Pa, Ni was evaporated to a thickness of 10 Å, and then Au was evaporated to a thickness of 300 Å.

[0156] By removing the resist with acetone, Ni / Au electrodes including a source electrode S and a drain electrode D were formed at each end of the graphene channel, thereby fabricating a field effect transistor using graphene as the channel material.

[0157] A field effect transistor was fabricated from the laminate and placed in a chamber equipped with a measurement probe (MJ-8, manufactured by Apollo Wave Co., Ltd.). －４The graphene channel surface was cleaned by treatment at 200°C for 15 hours under a reduced pressure of 0.1 Pa or less. The laminate was returned to room temperature while still under reduced pressure, and measurement probes were applied to the source electrode S and the drain electrode D. A semiconductor parameter analyzer (Keysight Corporation, B1500A) was used to measure the current (Id) flowing when 20 mV was applied between S and D while applying a variable voltage (Vg) of -40 to 40 V to the silicon (Si) substrate that would serve as the gate electrode G, and the electron mobility of the graphene was calculated.

[0158] The results of the measurements for Examples 1 to 8 and Comparative Examples 1 to 4 are summarized in Table 1 below. Note that the "tensile modulus of laminate" in Table 1 refers to the tensile modulus of the graphene / adhesive sheet laminate or the h-BN / adhesive sheet laminate (third laminate). However, in Comparative Example 1, the tensile modulus is shown for PMMA. Furthermore, "-" in Table 1 indicates that the measurement was not performed or could not be performed.

[0159]

[0160] In Examples 1 to 8, a pressure-sensitive adhesive sheet was used as a removable support layer, a bubble-forming step was included in the manufacturing process, and the elastic modulus of the graphene / pressure-sensitive adhesive sheet laminate or h-BN / pressure-sensitive adhesive sheet laminate (third laminate) was within the range of 10 to 3,000 MPa. As a result, the support layer was easily peeled from the graphene or h-BN, and the graphene or h-BN could be transferred at a high transfer rate. The transferred graphene or h-BN also had good low-contamination properties and high mobility. Furthermore, Example 1, in which the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet was cured by UV irradiation before the bubble-generating step, exhibited a higher graphene transfer rate and higher mobility than Examples 2 and 3. On the other hand, in Comparative Example 1, in which spin-coated PMMA was used as the support layer, the PMMA could not be peeled from the graphene. While it is possible to wash and remove the PMMA using a solvent, this requires a solvent washing step, which is less productive and raises concerns about damage to the graphene caused by the solvent. Here, when PMMA is washed and removed, the substrate is immersed in acetone at 50°C for 10 minutes, then removed, and without drying, is immersed in fresh acetone at 50°C for 30 minutes, then removed. This process is repeated twice, and the substrate is dried to fabricate a graphene transistor. The mobility is measured and found to be 1500 cm ２ / V / s. Furthermore, in Comparative Example 2, in which the elastic modulus of the graphene / adhesive sheet laminate (third laminate) was as high as 3902 MPa, the graphene transfer rate was poor. Furthermore, the mobility of the transferred graphene was low and the low contamination properties were also poor. In Comparative Examples 3 and 4, in which the manufacturing process did not include a bubble formation step, the graphene transfer rate was poor. Furthermore, Comparative Example 3 was also poor in the low contamination properties of graphene.

[0161] Although the present invention has been described in detail with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on a Japanese patent application (Patent Application No. 2023-223306) filed on December 28, 2023, the entirety of which is incorporated by reference.

[0162] 10: Support layer 11: Base material 12: Pressure-sensitive adhesive layer 21: First substrate 30: Two-dimensional material 40: Second substrate 101: Laminate (first laminate) 102: Laminate (second laminate) 103: Laminate (third laminate) 104: Laminate (fourth laminate) 105: Two-dimensional material laminate (fifth laminate)

Claims

1. A method for manufacturing a laminate, comprising: forming bubbles between the first substrate and the two-dimensional material in a state where a support layer is attached to the two-dimensional material on the first substrate; and separating a laminate including the support layer and the two-dimensional material from the first substrate by forming the bubbles or by pulling at least one of the support layer and the first substrate after forming the bubbles, wherein the support layer has re-peelability, and the tensile elastic modulus of the laminate at 23° C. under the following measurement conditions is 10 to 3000 MPa. (Measurement conditions for the tensile elastic modulus of the laminate) The initial tensile elastic modulus calculated from the slope of the stress with respect to strain between 10% strain and 100% strain when a sample of the laminate with a width of 10 mm and a length of 20 mm is chucked at 5 mm above and below in the length direction and pulled at a speed of 50 mm / min is defined as the tensile elastic modulus of the laminate.

2. The method for manufacturing a laminate according to claim 1, wherein the adhesive force of the support layer to the silicon wafer at 23° C. is 0.001 N / 20 mm to 2.0 N / 20 mm when a 180° peel is performed at a peeling speed of 300 mm / min.

3. The method for manufacturing a laminate according to claim 1, wherein the support layer is an adhesive tape including an adhesive layer and a base material.

4. The method for manufacturing a laminate according to claim 3, wherein the tensile elastic modulus of the base material at 23° C. under the following measurement conditions is 10 to 4000 MPa. (Measurement conditions for the tensile elastic modulus of the base material) The initial tensile elastic modulus calculated from the slope of the stress with respect to strain between 10% strain and 100% strain when a sample of the base material with a width of 10 mm and a length of 20 mm is chucked at 5 mm above and below in the length direction and pulled at a speed of 50 mm / min is defined as the tensile elastic modulus of the base material.

5. The method for manufacturing a laminate according to claim 3, wherein the tensile elastic modulus of the adhesive layer at 23° C. under the following measurement conditions is 1 to 1000 MPa. (Measurement conditions for the tensile elastic modulus of the adhesive layer) Using a cylindrical sample formed by rolling up the adhesive layer to a length of 30 mm and a diameter of 1 mm, the initial tensile elastic modulus calculated from the slope of the stress with respect to strain between 10% strain and 100% strain when chucked at 10 mm above and below in the length direction and pulled at a speed of 50 mm / min is defined as the tensile elastic modulus of the adhesive layer.

6. The method for manufacturing a laminate according to claim 3, wherein the adhesive layer is an adhesive layer that cures upon receiving a supply of a predetermined energy or substance.

7. The method for manufacturing a laminate according to claim 6, wherein the tensile elastic modulus at 23°C after curing of the adhesive layer under the following measurement conditions is 1 to 1000 MPa. (Measurement conditions for the tensile elastic modulus of the adhesive layer after curing) The adhesive layer is irradiated with ultraviolet rays having an integrated light amount of 450 mJ / cm ２ 2, and a cylindrical sample rolled to a length of 30 mm and a diameter of 1 mm is used. The upper and lower 10 mm in the length direction are chucked and pulled at a speed of 50 mm / min. The initial tensile elastic modulus calculated from the slope at the point where the slope of the stress with respect to the strain is maximized between 10% strain and 100% strain is taken as the tensile elastic modulus of the adhesive layer.

8. The method for manufacturing a laminate according to claim 6, including a step of supplying a predetermined energy or substance for curing the adhesive layer before the step of forming the bubbles.

9. A step of placing the laminate on the second substrate such that the surface on the two-dimensional material side of the laminate obtained by the method for manufacturing a laminate according to any one of claims 1 to 8 is in contact with the second substrate; and a step of peeling the support layer to transfer the two-dimensional material onto the second substrate to obtain a two-dimensional material laminate including the second substrate and the two-dimensional material. A method for manufacturing a two-dimensional material laminate.

10. A two-dimensional material having an area of 100 mm or more, laminated on a second substrate. ２ ​ 11. The two-dimensional material according to claim 10, having a transfer rate of 70% or more.

12. The two-dimensional material according to claim 10 or 11, having a contamination amount of -30% or more and 10% or less.

13. The two-dimensional material includes graphene and has a mobility of 2000 cm ２ / V / s or more, and the two-dimensional material according to claim 10 or 11.

Images