Silicone adhesives, adhesive sheets, and double-sided adhesive sheets

Abstract

[Problem] To provide a silicone-based adhesive, adhesive sheet, and double-sided adhesive sheet capable of effectively peeling off release sheets. [Solution] A silicone-based adhesive containing modified cyclodextrin. The modified cyclodextrin is preferably at least one of modified β-cyclodextrin and modified γ-cyclodextrin. Furthermore, the modified cyclodextrin is preferably a cyclodextrin modified with an amide group. The above-mentioned silicone-based adhesive is preferably an addition-reactive silicone-based adhesive.

Description

Silicone adhesives, adhesive sheets, and double-sided adhesive sheets This invention relates to a silicone-based adhesive, an adhesive sheet using the silicone-based adhesive, and a double-sided adhesive sheet. Various types of adhesive sheets for bonding components face-to-face have been known throughout history, and substrate-free double-sided adhesive sheets are known as one type of adhesive sheet. Generally, substrate-free double-sided adhesive sheets are formed by depositing a light release film with relatively low peel strength to the adhesive layer and a heavy release film with relatively high peel strength to the adhesive layer on both sides of an adhesive layer that does not have a substrate to serve as a core material. In the aforementioned substrate-free double-sided adhesive sheet, the light release film is first peeled off, and one side of the exposed adhesive layer is attached to a component. Then, the heavy release film is peeled off, and the other side of the exposed adhesive layer is attached to other components, thereby attaching the components to each other in a face-to-face manner. However, as a substrate-free double-sided adhesive sheet, one problem that can be listed is that when the light release film is peeled off, the adhesive layer that should remain on the heavy release film side may be pulled by the light release film and follow the light release film in poor peeling (so-called adhesion). To prevent poor peeling as described above, conventional methods have involved increasing the difference between the peeling force of the heavy-duty peeling film and the peeling force of the light-duty peeling film (see, for example, Patent Document 1). [Prior Art Documents] [Patent Documents] [Patent Document 1] Japanese Patent Application Publication No. 7-041736 [The problem the invention aims to solve] However, when the adhesive layer of the adhesive sheet is formed by a silicone-based adhesive, if a release film treated with a silicone-based release agent is used, the silicones have a high affinity for each other, the release force increases, and the aforementioned poor release will occur more significantly. Therefore, in adhesive sheets using silicone-based adhesives, release films treated with fluorinated release agents are typically used. However, the high price of release films treated with fluorinated release agents increases manufacturing costs. Therefore, there is a need for an adhesive sheet, particularly a substrate-free double-sided adhesive sheet, that can use a film that has not undergone the aforementioned release treatment as a release film. This invention was made in view of the following practical situation, and its object is to provide a silicone-based adhesive, adhesive sheet, and double-sided adhesive sheet capable of effectively peeling off release sheets. [Means for solving the problem] To achieve the above objectives, firstly, the present invention provides a silicone-based adhesive containing modified cyclodextrin (Invention 1). In the aforementioned invention (Invention 1), by including modified cyclodextrin, the surface roughness of the adhesive layer formed from the aforementioned silicone-based adhesive is increased. Therefore, the contact area with the release liner deposited on the adhesive layer is reduced, allowing for efficient peeling of the release liner from the adhesive layer. In other words, during the peeling of the release liner, the adhesive layer does not follow the release liner, thus suppressing poor peeling conditions such as adhesion. In the above invention (Invention 1), it is preferred that the modified cyclodextrin is at least one of modified β-cyclodextrin and modified γ-cyclodextrin (Invention 2). In the above inventions (Inventions 1 and 2), it is preferred that the modified cyclodextrin is a cyclodextrin modified by acetyl groups (Invention 3). Of the above inventions (Inventions 1-3), addition-reaction silicone adhesives are preferred (Invention 4). Second, the present invention provides an adhesive sheet, which is an adhesive sheet having at least an adhesive layer, characterized in that the adhesive layer is formed by the above-mentioned silicone-based adhesives (Inventions 1-4) (Invention 5). In the above invention (Invention 5), it is preferable that the arithmetic mean roughness (Ra) of the surface of the adhesive layer is 4 nm or more (Invention 6). Third, the present invention provides a double-sided adhesive sheet, which is a double-sided adhesive sheet having an adhesive layer, a first release sheet deposited on one side of the adhesive layer and a second release sheet deposited on the other side of the adhesive layer, characterized in that the adhesive layer is formed by the silicone-based adhesive (Invention 1-4) (Invention 7). In the above invention (Invention 7), the arithmetic mean roughness (Ra) of the surface of the adhesive layer exposed by peeling off the first release sheet or the second release sheet is preferably 4 nm or more (Invention 8). In the above-described inventions (Inventions 7 and 8), it is preferable that the first and second peeling sheets are plastic films that have not undergone peeling treatment (Invention 9). [Effects of the Invention] The silicone-based adhesive, adhesive sheet, and double-sided adhesive sheet of the present invention can effectively peel off the release sheet. The embodiments of the present invention will be described below. [Silicone-based adhesive] One embodiment of the silicone-based adhesive of the present invention is a silicone-based adhesive containing modified cyclodextrin. By containing this modified cyclodextrin, the surface roughness of the adhesive layer formed by the silicone-based adhesive is increased. Specifically, the arithmetic mean roughness (Ra) is 4 nm or more. Therefore, the contact area with the release liner deposited on the adhesive layer is reduced, and the release liner can be peeled off well from the adhesive layer. That is, when the release liner is peeled off, the adhesive layer does not follow the release liner, and poor peeling such as adhesion can be suppressed. Even when the release liner is an untreated plastic film, the above-mentioned effect can be achieved. Therefore, it is not necessary to use a release liner treated with a fluorinated release agent, which can reduce manufacturing costs. Furthermore, the above-mentioned effect can be achieved even in the case of a substrate-free double-sided adhesive sheet. Specifically, when peeling off one side of the plastic film from a substrate-free double-sided adhesive sheet sandwiched between two untreated plastic films, peeling defects such as adhesion can occur, and the plastic film can be peeled off well. Here, the surface roughness of the adhesive layer formed by the silicone-based adhesive of this embodiment increases after coating, as described above, if a conventional coating method is used. This surface roughness is maintained even after a release liner is deposited on the adhesive layer and then peeled off. Furthermore, the surface roughness is maintained even after the release liner, the object to which the silicone-based adhesive is coated, is peeled off from the adhesive layer on which it is formed. Specifically, the silicone-based adhesive of this embodiment contains a silicone-based adhesive main agent and a modified cyclodextrin. 1. Silicone-based adhesive: The silicone-based adhesive in this embodiment can be a condensation-type silicone adhesive or an addition-reaction-type silicone adhesive. From the viewpoint of compatibility with modified cyclodextrin and processability, an addition-reaction-type silicone adhesive is preferred. The addition-reactive silicone adhesive is preferably an addition-reactive silicone resin containing a first polydimethylsiloxane having at least two alkenyl groups in one molecule and a second polydimethylsiloxane having at least two hydrogenated silyl groups in one molecule, and a silicone resin. Examples of alkenyl groups contained in the first polydimethylsiloxane include, for example, monovalent hydrocarbon groups such as vinyl, allyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, and octenyl, with vinyl being particularly preferred. The alkenyl content (the ratio of the number of alkenyl groups to the number of methyl groups bonded to silicon atoms) in the first polydimethylsiloxane is preferably 0.005 to 0.1 mol%, particularly 0.01 to 0.05 mol%. The alkenyl groups are preferably present at both ends of the molecular chain, but may also be present in the side chains. Each molecule of the first polydimethylsiloxane contains at least two alkenyl groups. Furthermore, if the alkenyl content is within the above range, a cross-linked structure with high cross-linking density can be formed, and an adhesive layer with an excellent balance between adhesion and release properties can be obtained. The degree of polymerization (number of siloxane bonds) of the first polydimethylsiloxane is preferably 200 to 5,000, particularly 500 to 3,000. Furthermore, the content of hydrogenated silyl groups in the second polydimethylsiloxane is preferably 2 to 300 per molecule, particularly 4 to 200. The degree of polymerization of the second polydimethylsiloxane is preferably 50 to 2,000, particularly 100 to 1,500. Moreover, the proportion of the second polydimethylsiloxane relative to 100 parts by mass of the first polydimethylsiloxane is preferably 0.01 to 20 parts by mass, particularly 0.1 to 10 parts by mass. If the content of each functional group and the ratio of the second polydimethylsiloxane to the first polydimethylsiloxane are within the above range, the addition reaction between the first polydimethylsiloxane and the second polydimethylsiloxane can proceed well. Furthermore, the first polydimethylsiloxane is preferably free of hydrogenated silyl groups, and the second polydimethylsiloxane is preferably free of alkenyl groups. As a silicone resin, it can be used, for example, from a monofunctional siloxane unit [(CH 3) 3SiO 1 / 2 The M unit of ] and the tetrafunctional siloxane unit [SiO] 4 / 2 The MQ resin is formed from the Q unit of []. The molar ratio of M unit to Q unit is preferably 0.6 to 1.7. This silicone resin has the function of imparting adhesive properties to silicone adhesives. The preferred amount of silicone resin to be formulated relative to 100 parts by weight of addition-reaction silicone resin is 1 to 200 parts by weight, more preferably 5 to 120 parts by weight, particularly 10 to 80 parts by weight, and even more preferably 20 to 40 parts by weight. This achieves a good balance between adhesion and the release properties of the release sheet. The aforementioned addition-reaction silicone adhesive is preferably one containing a catalyst. The catalyst is not particularly limited as long as it can cure the addition-reaction silicone resin (the addition reaction between the first polydimethylsiloxane and the second polydimethylsiloxane), but platinum group metal compounds are preferred. Examples of platinum group metal compounds include, for instance, microparticle platinum, microparticle platinum adsorbed on a toner carrier, chloroplatinic acid, alcohol-modified chloroplatinic acid, olefin complexes of chloroplatinic acid, palladium, rhodium, etc. By using a catalyst containing such a catalyst, the curing reaction of the addition-reaction silicone resin can be carried out more effectively. Relative to the amount of catalyst in 100 parts by weight of the addition-reaction silicone resin mentioned above, the amount of platinum is preferably 0.01 to 3 parts by weight, particularly 0.05 to 2 parts by weight, and even more preferably 0.1 to 1 part by weight. This achieves a good balance between adhesion and the release properties of the release sheet. In addition to the above-mentioned components, the addition reaction type silicone adhesive may also contain various additives such as crosslinking agents, reaction inhibitors, colorants, and adhesion improvers. 2. Modified Cyclodextrins: In this embodiment, the modified cyclodextrins are cyclodextrins in which at least a portion of the hydroxyl groups are replaced by other functional groups. Generally, cyclodextrins are known to have five or more glucose constituent units. The cyclodextrin serving as the backbone of the modified cyclodextrin in this embodiment can be a cyclodextrin with five glucose constituent units, an α-cyclodextrin with six glucose constituent units, a β-cyclodextrin with seven glucose constituent units, or a γ-cyclodextrin with eight glucose constituent units. From the viewpoint of improving the surface roughness of the adhesive layer as described above, at least one of a modified β-cyclodextrin (modified β-cyclodextrin) and a modified γ-cyclodextrin (modified γ-cyclodextrin) is preferred in this embodiment. In the modified cyclodextrin of this embodiment, examples of functional groups (functional groups in which hydroxyl groups are replaced) that are used to modify the cyclodextrin include, for example, alkoxy groups such as methoxy and ethoxy, and acetyl groups such as acetyl. Among these, from the viewpoint of improving the surface roughness of the adhesive layer as described above, acetyl groups are preferred, and acetyl groups are particularly preferred. In this embodiment, the degree of modification of the modified cyclodextrin is preferably greater than 2.5, particularly 2.7 or higher, and even more preferably 2.8 or higher. On the other hand, the upper limit of the above-mentioned degree of modification is not particularly limited, and can be 3.0 or lower, particularly 2.99 or lower, and even more preferably 2.98 or lower. Furthermore, the degree of modification of the modified cyclodextrin referred to in this specification refers to the number of hydroxyl groups that are substituted by other functional groups in each glucose structural unit. Therefore, if all three hydroxyl groups in a glucose structural unit are substituted, the degree of modification is 3.0. In the silicone-based adhesive of this embodiment, the modified cyclodextrin can be used alone or in combination with two or more. In the silicone-based adhesive of this embodiment, the content of modified cyclodextrin is preferably 0.1% by mass or more, more preferably 0.3% by mass or more, particularly preferably 0.5% by mass or more, and further preferably 1% by mass or more. This effectively improves the surface roughness of the adhesive layer. Furthermore, in the silicone-based adhesive of this embodiment, the content of modified cyclodextrin is preferably 30% by mass or less, more preferably 20% by mass or less, particularly preferably 15% by mass or less, and further preferably 10% by mass or less. This allows the silicone-based adhesive of this embodiment to easily achieve the desired adhesive strength and also the desired peelability. [Adhesive Sheet] FIG1 shows a cross-sectional view of an adhesive sheet 1 according to an embodiment of the present invention. As shown in FIG1, the adhesive sheet 1 of this embodiment includes an adhesive layer 11, a substrate 12 laminated on one side of the adhesive layer 11, and a release sheet 13 laminated on the other side of the adhesive layer 11. 1. Constituent Elements (1) Adhesive Layer The adhesive layer 11 is formed of a silicone-based adhesive as described in the above embodiment. The thickness of the adhesive layer 11 is preferably 1 to 1000 μm, more preferably 3 to 500 μm, particularly preferably 5 to 100 μm, further preferably 10 to 50 μm, and preferably 15 to 35 μm. By making the thickness of the adhesive layer 11 within the above range, a good balance can be achieved between adhesive strength and the peelability of the release liner 13. The arithmetic mean roughness (Ra) of the surface of the release slab 13 side of the adhesive layer 11 is preferably 4 nm or more, more preferably 6 nm or more, particularly preferably 7 nm or more, further preferably 8 nm, and preferably 9 nm or more. This allows the release slab 13 to be effectively peeled from the adhesive layer 11. Such a large arithmetic mean roughness (Ra) can be obtained by coating the silicone-based adhesive of the above embodiment using conventional methods. Furthermore, the arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 on the release tab 13 side is preferably 100 nm or less, preferably 80 nm or less, particularly preferably 60 nm or less, further preferably 40 nm or less, and preferably 20 nm or less. This makes it easier for the adhesive layer 11 to exert the desired adhesive force. Details of the method for measuring the arithmetic mean roughness (Ra) of the adhesive layer surface in this specification are described in the test examples below. (2) The substrate, as substrate 12 in this embodiment, is not particularly limited, and any material used as a substrate for general adhesive sheets can be used. Examples include, for instance, polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyurethane films, polyethylene films, polypropylene films, cellulose films such as triacetyl cellulose; polyvinyl chloride films, polyvinylidene chloride films, polyvinyl alcohol films, ethylene vinyl acetate copolymer films, polystyrene films, polycarbonate films, acrylic resin films, norcamphene resin films, and cyclic olefin resin films; plastic sheets formed from the above-mentioned resins; woven or non-woven fabrics using fibers such as rayon, acrylic, and polyester; synthetic paper; paper such as high-grade paper, cellophane, impregnated paper, and coated paper; metal bodies such as aluminum and copper; foams such as polyurethane foam and polyethylene foam; and laminates of two or more of the above. Furthermore, the substrate 12 can be something that can be peeled off from the adhesive layer 11 (e.g., a release liner). In the case that the substrate 12 is a release liner, the adhesive sheet 1 of this embodiment becomes a double-sided adhesive sheet as described later. The thickness of the substrate 12 varies depending on its type, with 5–300 μm being preferred, 10–200 μm being even better, and especially 15–100 μm being preferred. (3) As the release sheet 13 in this embodiment, a plastic film is preferably used. Examples of plastic films include, for instance, polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polypropylene and polymethylpentene, polyvinyl chloride, vinyl chloride copolymers, polyvinyl acetate, ethylene vinyl acetate, ionomer resins, ethylene-(meth)acrylate copolymers, polyurethane, polystyrene, polycarbonate, polyimide, and fluoropolymers. These plastic films can be single-layered or multilayered, consisting of two or more layers of the same or different types. Furthermore, these plastic films can be uniaxially or biaxially extended. Polyester films are preferred, especially polyethylene terephthalate films. Polyethylene terephthalate (PET) films are less prone to dust generation during processing and use, thus effectively preventing coating defects caused by dust. Furthermore, their relatively low price helps reduce production costs. From the viewpoint of being able to peel off easily from the adhesive layer 11, the aforementioned plastic film is preferably a plastic film that has not undergone a peeling treatment. When using a plastic film that has not undergone a peeling treatment, since no peeling treatment is required, the amount of material (release agent) used can be reduced, contributing to lower production costs. In particular, since resources can be used more efficiently and it becomes one of the environmentally friendly technologies and production methods, it can contribute to achieving the Sustainable Development Goals (SDGs). However, release agents other than silicone-based release agents can also be used; for example, plastic films that have undergone peeling treatment with fluorinated release agents can be used. From the viewpoint of peelability and operability, the thickness of the release strip 13 is preferably 5 to 300 μm, more preferably 10 to 200 μm, especially preferably 15 to 100 μm, and even more preferably 20 to 50 μm. 2. Manufacturing Method The manufacturing method of the adhesive sheet 1 in this embodiment is not particularly limited. As an example of manufacturing the adhesive sheet 1, an adhesive coating liquid containing the above-mentioned silicone-based adhesive and a diluent as needed can be applied to the substrate 12, and then dried and cured to form an adhesive layer 11. The application of adhesive coating liquid can be carried out by conventional methods, such as rod coating, blade coating, roller coating, stencil coating, and gravure coating. There are no particular limitations on the diluents used, and a wide variety of diluents can be used. Examples include hydrocarbon compounds such as toluene, hexane, and heptane, acetone, ethyl acetate, methyl ethyl ketone, methyl isobutyl ketone, and mixtures thereof. When the silicone adhesive is an addition-reaction type silicone adhesive, it is preferable to heat-cure the applied adhesive coating. In this case, the heating temperature is preferably 80–180°C, and the heating time is preferably 30–240 seconds. After forming the adhesive layer 11 as described above, the release sheet 13 is attached to the adhesive layer 11 to obtain the adhesive sheet 1. Even using the conventional coating method described above, the arithmetic mean roughness (Ra) of the surface of the release slab 13 side of the adhesive layer 11 increases to 4 nm or more. Furthermore, this arithmetic mean roughness (Ra) can be maintained even after the release slab 13 is deposited on the adhesive layer 12 and then peeled off. By increasing the arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 in this way, the release slab 13 can be peeled off well from the adhesive layer 11. [Double-sided adhesive sheet] FIG2 shows a cross-sectional view of a double-sided adhesive sheet 2 according to an embodiment of the present invention. As shown in FIG2, the double-sided adhesive sheet 2 of this embodiment includes an adhesive layer 11, a first release sheet 21 deposited on one side of the adhesive layer 11, and a second release sheet 22 deposited on the other side of the adhesive layer 11. In this embodiment, as an example, the second release sheet 22 is the object to which the coating liquid of the silicone adhesive constituting the adhesive layer 11 is applied, and the first release sheet 21 is the object to which it is adhered to the formed adhesive layer 11. However, the present invention is not limited thereto. 1. Constituent elements (1) Adhesive layer The adhesive layer 11 is formed by the silicone adhesive of the embodiment described above. The thickness of the adhesive layer 11 is the same as the thickness of the adhesive layer 11 of the adhesive sheet 1. The arithmetic mean roughness (Ra) of the surface of the first release tab 21 side of the adhesive layer 11 is the same as the arithmetic mean roughness (Ra) of the surface of the release tab 13 side of the adhesive tab 1. This allows the first release tab 21 to be effectively peeled from the adhesive layer 11 on the second release tab 22, and suppresses poor peeling caused by adhesion. On the other hand, the arithmetic mean roughness (Ra) of the surface of the second release tab 22 side of the adhesive layer 11 is preferably 4 nm or more, more preferably 4.5 nm or more, particularly preferably 5 nm or more, and even more preferably 5.5 nm or more. This allows the second release tab 22 to be effectively peeled off from the adhesive layer 11 (attached to the adhered body). Furthermore, the arithmetic mean roughness (Ra) of the surface of the second release tab 22 side of the adhesive layer 11 is preferably 100 nm or less, more preferably 80 nm or less, particularly preferably 60 nm or less, further preferably 40 nm or less, and preferably 20 nm or less. This makes it easier for the adhesive layer 11 to exert the desired adhesive force. In the double-sided adhesive sheet 2 of this embodiment, the adhesive layer 11 is preferably without a substrate as a core material; that is, the double-sided adhesive sheet 2 of this embodiment is preferably a substrate-free double-sided adhesive sheet. Substrate-free double-sided adhesive sheets are particularly prone to poor peeling when the release liner is initially peeled off, but with the double-sided adhesive sheet 2 of this embodiment, such poor peeling can be suppressed. (2) The first and second release sheets The materials and thicknesses of the first release sheet 21 and the second release sheet 22 are the same as those of the release sheet 13 of the adhesive sheet 1 mentioned above. In the double-sided adhesive sheet 2 of this embodiment, it is preferable that the peeling force of the second release tab 22 on the adhesive layer 11 is greater than that of the first release tab 21 on the adhesive layer 11. This effectively suppresses the adhesion of the adhesive layer 11 to the second release tab 22 when the first release tab 21 is peeled off from the adhesive layer 11, preventing it from being pulled away by the first release tab 21. By applying a coating liquid of the silicone-based adhesive constituting the adhesive layer 11 onto the second release tab 22 and attaching the first release tab 21 to the formed adhesive layer 11, the peeling force can be adjusted as described above. In this embodiment, the peel force of the first release tab 21 on the adhesive layer 11 is preferably 1 to 200 mN / 25 mm, more preferably 5 to 150 mN / 25 mm, particularly preferably 10 to 100 mN / 25 mm, further preferably 15 to 70 mN / 25 mm, and most preferably 20 to 50 mN / 25 mm. This allows the first release tab 21 to be easily and without problems when it is first peeled from the adhesive layer 11. Furthermore, it prevents the first release tab 21 from peeling off the adhesive layer 11 unintentionally. Details of the peel force measurement method in this specification are described in the test examples below. In this embodiment, the peeling force of the second release tab 22 on the adhesive layer 11 is preferably 5 to 300 mN / 25 mm, more preferably 10 to 210 mN / 25 mm, particularly preferably 15 to 110 mN / 25 mm, further preferably 25 to 80 mN / 25 mm, and most preferably 30 to 60 mN / 25 mm. This effectively prevents the adhesive layer 11 from peeling off from the second release tab 22 when the first release tab 21 is peeled off from the adhesive layer 11. Furthermore, the second release tab 22 can be easily peeled off from the adhesive layer 11 attached to the adhered body without any problems. The difference in peeling force between the first release tab 21 and the second release tab 22 is preferably 1 to 150 mN / 25 mm, more preferably 5 to 100 mN / 25 mm, particularly preferably 7 to 80 mN / 25 mm, further preferably 10 to 50 mN / 25 mm, and optimally 12 to 30 mN / 25 mm. This allows the first release tab 21 to be peeled from the adhesive layer 11 without adhesion or other problems. 2. Manufacturing Method of Double-Sided Adhesive Sheet As a preferred manufacturing example of the double-sided adhesive sheet 2 of this embodiment, an adhesive coating liquid containing the aforementioned silicone-based adhesive and a desired diluent can be applied to the second release sheet 22, and then dried and cured to form an adhesive layer 11. Specifically, the adhesive layer 11 can be formed in the same manner as the adhesive sheet 1 described above. After forming the adhesive layer 11, the first release sheet 21 is attached to this adhesive layer 11 to obtain the double-sided adhesive sheet 2. By using the aforementioned silicone-based adhesive, even using conventional coating methods, the arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 on the side of the first release slab 21 can be increased to 4 nm or more. Furthermore, this arithmetic mean roughness (Ra) can be maintained even after the first release slab 21 is deposited on the adhesive layer 22 and then peeled off. By increasing the arithmetic mean roughness (Ra) of the surface of the adhesive layer 11 in this way, when the first release slab 21 is peeled off from the adhesive layer 11, the adhesive layer 11 will not follow the first release slab 21 and peel off from the second release slab 22, thus suppressing the occurrence of poor peeling such as adhesion. [Another Embodiment] In another embodiment of the present invention, the adhesive sheet has at least an adhesive layer, wherein the adhesive layer is formed of a silicone-based adhesive, and the arithmetic mean roughness (Ra) of the surface of the adhesive layer is 4 nm or more. The adhesive sheet of this embodiment can be a double-sided adhesive sheet or a substrate-free double-sided adhesive sheet. By making the arithmetic mean roughness (Ra) of the adhesive layer surface greater than 4 nm, the contact area between the adhesive layer and the release liner deposited on the adhesive layer is reduced, allowing for good peeling when the release liner is removed from the adhesive layer. In other words, the adhesive layer does not follow or adhere to the release liner, thus suppressing poor peeling caused by adhesion. The silicone adhesive constituting the adhesive layer is preferably the silicone adhesive of the embodiment described above, but is not limited thereto. Other than the above, the structure is the same as the adhesive sheet 1 or double-sided adhesive sheet 2. The embodiments described above are provided for ease of understanding of the present invention and are not intended to limit the invention. Therefore, the elements disclosed in the above embodiments are intended to include all design changes and equivalents that fall within the scope of the present invention. For example, the adhesive layer 11 may be a material with a core material. Furthermore, in this specification, when "X~Y" (where X and Y are arbitrary numbers) is used, unless otherwise stated, it means "X or more and Y or less," and also includes the meaning of "preferably greater than X" or "preferably less than Y." Moreover, when "X or more" (where X is any number) is used, unless otherwise stated, it includes the meaning of "preferably greater than X"; when "Y or less" (where Y is any number) is used, unless otherwise stated, it includes the meaning of "preferably less than Y." [Example] The invention will be described in more detail below by way of examples, but the scope of the invention is not limited to these examples. [Preparation Example 1] 1.8 g of β-cyclodextrin (manufactured by Nacalai Tesque) and 47 mg of p-toluenesulfonic acid monohydrate as a catalyst were added to 8.5 ml of isopropyl acetate as a solvent, and the mixture was reacted at 70°C for 16 hours. The reaction solution was removed by vacuum distillation, and the resulting solid was washed with a 10% sodium carbonate aqueous solution, extracted with chloroform, and recrystallized with acetone to obtain 2.5 g of acetylated β-cyclodextrin as a white solid. A portion of the obtained acetylated β-cyclodextrin was dissolved in deuterated chloroform, and then... 1 The analysis was performed using H-NMR (manufactured by Nippon Electron, trade name "Nuclear Magnetic Resonance Apparatus JNM-LA400 / WB"). The results were then analyzed using... 1 The degree of modification was calculated to be 2.98 based on the integral ratio of the peak at 5.1 ppm (originating from the proton at the first carbon of the glucose ring) to the peak at 2.1 ppm (originating from the acetyl group). [Preparation Example 2] 2 g of γ-cyclodextrin (manufactured by Nacalai Tesque) and 47 mg of p-toluenesulfonic acid monohydrate as a catalyst were added to 8.5 ml of isopropyl acetate as a solvent, and the mixture was reacted at 70°C for 16 hours. The reaction solution was removed by vacuum distillation, and the resulting solid was washed with a 10% sodium carbonate aqueous solution, extracted with chloroform, and recrystallized with acetone to obtain 2.5 g of acetylated γ-cyclodextrin as a white solid. A portion of the obtained acetylated γ-cyclodextrin was dissolved in deuterated chloroform, and by means of 1 The analysis was performed using H-NMR (manufactured by Nippon Electron, trade name "Nuclear Magnetic Resonance Apparatus JNM-LA400 / WB"). The results were then analyzed using... 1 The degree of modification was calculated to be 2.97 based on the integral ratio of the peak at 5.1 ppm (originating from the proton at the first carbon of the glucose ring) to the peak at 2.1 ppm (originating from the acetyl group). [Example 1] 1. Preparation of adhesive coating liquid 100 parts by weight of addition-reactive silicone resin (manufactured by Shin-Etsu Chemical Co., Ltd., "KS-847H") (solid component conversion; the same applies below), 30 parts by weight of silicone resin (manufactured by Dow Corning Toray Co., Ltd., "SD-4584"), 0.5 parts by weight of platinum catalyst (manufactured by Dow Corning Toray Co., Ltd., "SRX 212 CATALYST"), 3 parts by weight of acetylated γ-cyclodextrin prepared in Preparation Example 2, and methyl ethyl ketone as a diluent were mixed and this mixture was used as the adhesive coating liquid. 2. Manufacturing the double-sided adhesive sheet: The adhesive coating liquid obtained in step 1 above is applied to one side of the polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "DIAFOIL T100-50S", thickness 50 μm), which serves as the second release sheet, using a doctor blade coater. Then, the coating layer is heat-treated at 120°C for 2 minutes to form a coating layer with a thickness of 25 μm. Next, the adhesive layer on the second release liner obtained above is bonded to the polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "DIAFOIL T100-50S", thickness 50 μm) serving as the first release liner, thereby creating a double-sided adhesive sheet with an adhesive layer thickness of 25 μm. That is, a substrate-free double-sided adhesive sheet formed by the structure of the first release liner / adhesive layer (thickness: 25 μm) / second release liner. Furthermore, the thickness of the adhesive layer is a value measured according to JIS K7130 using a constant pressure thickness gauge (manufactured by Teclock Corporation, product name "PG-02"). [Examples 2-3, Comparative Example 1] The types and amounts of the components of the adhesive coating liquid were changed according to Table 1. Otherwise, a substrate-free double-sided adhesive sheet was manufactured in the same manner as in Example 1. [Reference Example 1] As the first release sheet, a release sheet (manufactured by Lintec Corporation, product name "SP-PET751130") that has been treated with a silicone-based release agent on one side of a polyethylene terephthalate film is used. The treated side of this first release sheet is attached to the adhesive layer on the second release sheet. Otherwise, a substrate-free double-sided adhesive sheet is manufactured in the same manner as in Example 1. [Experimental Example 1] (Measurement of Surface Roughness) The second release sheet side of the substrate-free double-sided adhesive sheet manufactured in the Examples, Comparative Examples, and Reference Examples was fixed to a glass plate using double-sided adhesive tape. Then, the first release sheet was peeled off from the substrate-free double-sided adhesive sheet, and the exposed adhesive layer surface (first release sheet side) was observed at 50x magnification in PSI mode using an optical interference surface shape observation device (manufactured by Veeco Corporation, Japan, product name "NT1100"), and the arithmetic mean roughness (Ra) (nm) was measured. At this time, images of 120 μm × 120 μm areas were obtained from the surface shape images, and the arithmetic mean roughness (Ra) (nm) was measured in each image. The average of these values ​​was taken as the arithmetic mean roughness (Ra) (nm). The results are shown in Table 2. Furthermore, the arithmetic mean roughness (Ra) (nm) of the surface of the second release liner side of the adhesive layer was measured in the same manner as described above. The results are shown in Table 2. [Test Example 2] (Determination of Peel Strength) The substrate-free double-sided adhesive sheet manufactured in the Examples, Comparative Examples and Reference Examples was cut into pieces 25 mm wide and 100 mm long. Then, the second release sheet was peeled off, and the exposed adhesive layer was bonded to alkali-free glass (manufactured by Corning Incorporated, product name "Eagle XG") to obtain the test sample. For the obtained test samples, a tensile testing machine (manufactured by Orientec, product name "TENSILON") was used to peel the first release tab from the adhesive layer at a peel speed of 300 mm / min and a peel angle of 180 degrees, and the peel force (N / 25mm) of the first release tab was measured. Other test conditions were performed according to JIS Z0237:2009. The results are shown in Table 2. Furthermore, in Reference Example 1, the adhesion between the first release tab and the adhesive layer was so strong that peeling occurred between the adhesive layer and the alkali-free glass, making it impossible to measure the peel force between the first release tab and the adhesive layer. Furthermore, the peel force (mN / 25mm) of the second release tab was measured in the same manner as described above. The results are shown in Table 2. Also, in Comparative Example 1, the adhesion between the second release tab and the adhesive layer was so strong that the adhesive layer peeled off from the alkali-free glass, making it impossible to measure the peel force between the second release tab and the adhesive layer. [Experimental Example 3] (Evaluation of transferability) An acrylate polymer (weight average molecular weight: 1.5 million) was prepared by copolymerizing 99 parts by mass of n-butyl acrylate and 1 part by mass of 4-hydroxybutyl acrylate by solution polymerization. The above weight-average molecular weight (Mw) is the converted weight-average molecular weight of polystyrene determined by gel permeation chromatography (GPC) under the following conditions (GPC determination). <Determination Conditions> ・GPC apparatus: Tosoh Corporation, HLC-8020 ・GPC columns (passing in the following order): Tosoh Corporation, TSK guard column HXL-H, TSK gel GMHXL (x 2), TSK gel G2000HXL ・Determination solvent: Tetrahydrofuran ・Determination temperature: 40℃ 100 parts by weight of the (meth)acrylate polymer obtained above (solid component conversion value, the same below) are mixed with 0.2 parts by weight of trimethylolpropane-modified phenyl dimethyl diisocyanate (manufactured by Soken Chemical Co., Ltd., trade name "TD-75") as crosslinking agent (B), stirred thoroughly, and diluted with methyl ethyl ketone to obtain an acrylic adhesive coating liquid. After the obtained acrylic adhesive coating liquid was applied to the glass plate, it was heated at 130°C for 1 minute to form an acrylic adhesive layer with a thickness of 25 μm. The second release sheet was peeled off from the substrate-free double-sided adhesive sheet manufactured in the Examples, Comparative Examples, and Reference Examples, and the exposed adhesive layer (silicone adhesive layer) was adhered to the aforementioned acrylic adhesive layer. Afterwards, it was left to stand at room temperature for 24 hours and used as a sample. Using a tensile testing machine (manufactured by Orientec, product name "TENSILON"), the first release sheet was peeled from the silicone adhesive layer of the above sample at a peel speed of 300 mm / min and a peel angle of 90 degrees. If the first release sheet could be peeled off without problems while maintaining the transfer of the silicone adhesive layer to the acrylic adhesive layer, it was evaluated as having good transferability (○); if the silicone adhesive layer peeled off from the acrylic adhesive layer together with the first release sheet, it was evaluated as having poor transferability (×). The results are shown in Table 2. [Table 1] [Table 2] As shown in Table 2, the substrate-free double-sided adhesive sheets manufactured in the examples exhibit good transferability of the adhesive layer (silicone adhesive layer), and the release sheets formed from the polyethylene terephthalate film demonstrate excellent peelability. [Industrial Applicability] The silicone-based adhesive, adhesive sheet, and double-sided adhesive sheet of the present invention are suitable for bonding, for example, components such as curved displays, curved glass, and functional / decorative films. 1: Adhesive sheet; 11: Adhesive layer; 12: Substrate; 13: Release sheet; 2: Double-sided adhesive sheet; 21: First release sheet; 22: Second release sheet [Figure 1] is a cross-sectional view of an adhesive sheet according to an embodiment of the present invention. [Figure 2] is a cross-sectional view of a double-sided adhesive sheet according to an embodiment of the present invention. 1: Adhesive sheet 11: Adhesive layer 12: Substrate 13: Peeling tablets

Claims

1. An adhesive sheet having at least an adhesive layer, characterized in that the adhesive layer is formed of a silicone-based adhesive containing modified cyclodextrin, wherein, The modified cyclodextrin is a cyclodextrin modified with acetyl groups, wherein the arithmetic mean roughness (Ra) of the surface of the adhesive layer is 4 nm or more.

2. The adhesive sheet as described in claim 1, wherein, The aforementioned modified cyclodextrin is at least one of modified β-cyclodextrin and modified γ-cyclodextrin.

3. The adhesive sheet as described in claim 1 is an addition-reactive silicone adhesive.

4. The adhesive sheet as described in claim 1, wherein, The degree of modification of the above-mentioned modified cyclodextrin is greater than 2.

5.

5. The adhesive sheet as described in claim 1, wherein, The content of the modified cyclodextrin in the above-mentioned silicone adhesive is more than 0.1% by mass and less than 30% by mass.

6. A double-sided adhesive sheet comprising: an adhesive layer, a first release sheet deposited on one side of the adhesive layer, and a second release sheet deposited on the other side of the adhesive layer, characterized in that the adhesive layer is formed from the adhesive layer of the adhesive sheet as described in any one of claims 1 to 5.

7. The double-sided adhesive sheet as described in claim 6, wherein, The arithmetic mean roughness (Ra) of the surface of the adhesive layer exposed after peeling off the first or second release sheet is 4 nm or more.

8. The double-sided adhesive sheet as described in claim 6, wherein, The first and second peeling sheets mentioned above are plastic films that have not undergone peeling treatment.

Images