WO2024071061A1

WO2024071061A1 - Adhesive sheet, adhesion method, and wound body

Info

Publication number: WO2024071061A1
Application number: PCT/JP2023/034800
Authority: WO
Inventors: 絢子服部; 功弘長尾
Original assignee: 積水化学工業株式会社
Priority date: 2022-09-27
Filing date: 2023-09-26
Publication date: 2024-04-04
Also published as: TW202424141A

Abstract

Provided is an adhesive sheet with which winding misalignment is unlikely to occur during construction, and wrinkling after attachment is also unlikely to occur.　This adhesive sheet includes a laminate in which a peeling layer, a base layer, and an adhesive layer are laminated in this order, and a release processing layer is formed on the surface of the peeling layer on the side opposite to the base layer. The adhesive sheet of the present invention makes winding misalignment unlikely to occur during construction, and also makes wrinkling after attachment unlikely to occur.

Description

Adhesive sheet, adhesion method and roll

The present invention relates to an adhesive sheet, an adhesive method using the adhesive sheet, and a rolled body.

Conventionally, an adhesive sheet comprises a base layer and an adhesive layer formed on the base layer, with a protective layer provided on the surface of the adhesive layer opposite the base layer. When attaching the adhesive sheet to an object, the protective layer is peeled off and the adhesive layer is attached to the object. Such adhesive sheets are widely used for a variety of purposes, including repair and joining.

In order to efficiently apply an adhesive sheet to an object, it is desirable for the adhesive sheet to be in a roll shape (rolled body), as typified by craft tape and masking tape. In a roll-shaped adhesive sheet, the surface opposite the adhesive surface of the base layer is generally subjected to a release treatment, which makes it easy to unroll the adhesive sheet from the roll shape. However, when a release treatment is applied to the base layer, the overlapping properties of the adhesive sheet may be reduced.

In order to improve the overlapping properties of an adhesive sheet, for example, Patent Document 1 discloses a technique in which a release agent made of a specific material is applied to the base layer of the adhesive sheet. This technique allows the adhesive sheet to be easily unfolded even in a roll shape, and also enables overlapping (i.e., overlapping of the adhesive layer and the base layer). However, in this case, the adhesive sheet is limited to applications where the adhesive strength (self-backside adhesive strength) during overlapping can be at a low level, and the range of application of the adhesive sheet is likely to be limited. In applications that require higher self-backside adhesive strength, an adhesive sheet with release paper or the like attached to the adhesive surface (adhesive surface) may be used.

JP 2000-303018 A

However, when using a rolled adhesive sheet with release paper or the like affixed to the adhesive surface for installation, the adhesive sheet must be unrolled from the core of the roll while the release paper is peeled off, resulting in the problem of time-consuming installation. In recent years, there has been a desire to use fully automatic robots in infrastructure maintenance and other areas to avoid dangerous work by humans at high altitudes as much as possible, but the inventors have found that when a robot performs installation while peeling off the release paper, the sheet is more likely to become misaligned than when a human works as it does so. In addition, the inventors have found that when a robot performs installation while peeling off the release paper, the sheet is more likely to twist when correcting the robot's skew, and as a result, wrinkles are more likely to occur after application.

The present invention was made in consideration of the above, and aims to provide an adhesive sheet that is less likely to slip when applied and is also less likely to wrinkle after application.

As a result of extensive research into achieving the above objective, the inventors discovered that the above objective could be achieved by applying a laminate having a specific layer structure, leading to the completion of the present invention.

That is, the present invention includes, for example, the subject matter described in the following sections.
Item 1
The laminate includes a release layer, a base layer, and an adhesive layer laminated in this order,
An adhesive sheet, wherein a release treatment layer is formed on the surface of the release layer opposite to the base layer.
Item 2
the distance between peaks of a peel SS curve obtained when the adhesive layer is adhered to the release layer and then the adhesive layer is peeled off is 5 mm or less;
Item 2. The adhesive sheet according to item 1, wherein the peak-to-peak distance of the peel SS curve is measured by the following peel measurement.
<Peeling measurement>
A 20 mm wide laminate is prepared, and only the release layer is peeled off from the laminate to separate the release layer and the composite layer having the base layer and the adhesive layer. The surface of the peeled release layer opposite the release treatment layer is attached to the surface of a SUS plate with double-sided adhesive tape, and the adhesive layer side of the composite layer is attached to the release layer, and a 2 kg roller is reciprocated twice from one end of the composite layer to the other end to perform a pressure bonding process. 24 hours after the pressure bonding process, the distance between each apex in the range of 20 mm to 50 mm from the peel start point is measured in the peel SS curve obtained when one end of the composite layer is peeled off at an angle of 90° at a speed of 1500 mm/min to 50 mm, and the average value of these is taken as the mountain distance of the peel SS curve.
Item 3
3. The adhesive sheet according to

item

1 or 2, having a strength at 10% elongation of 50 N/24 mm or less.
Item 4
Item 4. The adhesive sheet according to any one of items 1 to 3, having a weak adhesive layer between the release layer and the substrate layer.
Item 5
Item 5. The adhesive sheet according to any one of items 1 to 4, which is for application by a robot.
Item 6
Item 6. The adhesive sheet according to any one of items 1 to 5, which is for repairing a wind power generation blade.
Item 7
Item 7. A bonding method using the adhesive sheet according to any one of items 1 to 6,
The adhesive sheet is attached to an object, and then the release layer is peeled off.
Item 8
Item 7. A rolled body comprising the adhesive sheet according to any one of items 1 to 6 wound around a cylindrical core material.

The adhesive sheet of the present invention is less likely to slip when applied, and is also less likely to wrinkle after application.

1 is a side view showing a portion of an example of an embodiment of an adhesive sheet of the present invention. 1 shows one embodiment of a peel SS curve obtained by peel measurement of an adhesive sheet of the present invention. 1A is a schematic diagram of an adherend 50 used to evaluate the rolling slippage, wrinkles, and curved surface conformability of an adhesive sheet, in which (a) is a front view of the adherend, (b) is a side view of the adherend, and (c) is a plan view of the adherend.

The following describes in detail the embodiments of the present invention. In this specification, the expressions "contain" and "include" include the concepts of "contain," "include," "consist essentially of," and "consist only of."

The adhesive sheet of the present invention includes a laminate in which a release layer, a base layer, and an adhesive layer are laminated in this order, and a release treatment layer is formed on the surface of the release layer opposite the base layer.

The adhesive sheet of the present invention is less likely to slip when applied, and is also less likely to wrinkle after application. Therefore, the adhesive sheet of the present invention has excellent application properties.

FIG. 1 is a schematic diagram for explaining the layer structure of the adhesive sheet of the present invention. Specifically, FIG. 1 shows adhesive sheet A, which is an example of the adhesive sheet of the present invention. Adhesive sheet A includes a laminate 10 in which a release layer 1, a base layer 2, and an adhesive layer 3 are laminated in this order. A release treatment layer 1a is formed on the surface of release layer 1 opposite to the base layer 2.

In the adhesive sheet of the present invention, the release layer is a layer for protecting the substrate, and is a layer provided on the surface of the substrate opposite the adhesive layer. Therefore, when the adhesive sheet is a roll, the adhesive layer is superimposed on the surface of the release layer opposite the substrate.

The release layer can be made of various materials, and for example, various films and protective sheets that have been conventionally used to protect the adhesive surface of adhesive tapes and the like can be widely used as the release layer. Such a release layer can be made of a substrate having a layer of adhesive (hereinafter referred to as a "weakly adhesive layer") formed on one side (in other words, the release layer has a laminated structure consisting of the weakly adhesive layer and the substrate). Thus, in the adhesive sheet shown in FIG. 1, a weakly adhesive layer (not shown) is formed on the side of the release layer 1 opposite the release treatment layer 1a, and this weakly adhesive layer is bonded to the base layer 2.

Examples of substrates that form the release layer include polyolefin resins such as polyethylene and polypropylene, and polyester resins such as polyethylene terephthalate.

The slightly adhesive layer in the release layer is formed for the purpose of temporarily adhering to the substrate to protect the substrate. Therefore, the slightly adhesive layer does not usually remain on the substrate layer when the release layer is peeled off from the substrate layer. The type of slightly adhesive layer is not particularly limited, and examples include layers formed from various adhesives. Examples of adhesives include various adhesives such as pressure-sensitive adhesives, thermosetting adhesives, and photocuring adhesives. Specific components of the adhesive include acrylic adhesives, epoxy adhesives, urethane adhesives, and silicone adhesives.

As described above, the release treatment layer in the release layer is a layer formed on the surface of the release layer opposite the base layer. Such a release treatment layer is a layer that allows the adhesive layer to be easily peeled off from the release layer when the adhesive layer is superimposed on the release layer, for example, when the adhesive sheet is a roll.

The release treatment layer can be formed, for example, with a release treatment agent. Examples of release treatment agents include silicone-based release agents and compounds containing long-chain alkyl groups.

In view of the above, it is preferable that the release layer has a release treatment layer on the surface opposite to the base layer. It is preferable that the surface of the release layer that is bonded to the base layer has the above-mentioned weak adhesive layer.

The method for forming the release layer provided with the release treatment layer is not particularly limited, and examples of the method include treating one side of the substrate with the adhesive and the other side with a release treatment agent. The method for treating the substrate with the release agent and release treatment agent is not particularly limited, and for example, any known method can be widely used. The release layer can also be obtained from commercial products. Examples of commercially available release layers include "VE-210WBF" and "DE600" from Sumiron Corporation, and "NOVACEL #4336" (registered trademark) from Sekisui Material Solutions Corporation.

The thickness of the release layer (including the thickness of the release treatment layer) is not particularly limited and can be, for example, 15 to 150 μm.

In the adhesive sheet of the present invention, the substrate layer is the layer that forms the base of the adhesive sheet and is the layer that holds the adhesive layer.

The substrate layer can be formed from various materials, and for example, a wide variety of materials that are used to form known adhesive sheets can be used. Examples of the substrate layer include polyolefin resins such as polyethylene, polyester resins such as polyethylene terephthalate, polyurethane resins, polyurea resins, etc., and materials other than resins, such as paper and cloth, can also be used. The substrate layer can be formed from one or more types of materials.

The substrate may have a single layer structure, or it may have a laminated structure in which multiple layers are stacked. An example of a laminated structure is a structure that includes a core material inside.

The substrate layer can be formed, for example, by a known method, or can be obtained as a commercially available product. An example of a commercially available substrate layer is BASF's "NY585."

The thickness of the substrate layer is not particularly limited and can be, for example, 50 to 3000 μm, and is preferably 50 to 1000 μm.

In the adhesive sheet of the present invention, the adhesive layer is a layer that provides adhesive functionality to the adhesive sheet and is formed on the base layer.

The adhesive layer can be formed, for example, from various adhesives. Examples of adhesives for forming the adhesive layer include various adhesives such as pressure-sensitive adhesives, heat-curing adhesives, and light-curing adhesives. Specific adhesive components include acrylic adhesives, epoxy adhesives, urethane adhesives, and silicone adhesives. The adhesives can be manufactured by known methods. The adhesive layer can also be obtained from commercial products; for example, the "Sekisui SJ" series from Sekisui Chemical Co., Ltd. can be used as the adhesive layer.

The adhesive layer can be formed, for example, by a known method, for example, by applying the adhesive onto the base layer to form the adhesive layer. The method of applying the adhesive onto the base layer is not particularly limited, and for example, any known application method can be widely used. Alternatively, the adhesive layer can be formed by attaching a tape-like adhesive layer or the like onto the base layer.

The thickness of the adhesive layer is not particularly limited and can be, for example, 20 to 1500 μm, preferably 50 to 1000 μm.

It is preferable that no other layers, such as a release layer, are formed on the side of the adhesive layer opposite the substrate.

As described above, the adhesive sheet of the present invention includes a laminate in which a release layer having a release treatment layer, a base layer, and an adhesive layer are laminated in this order. In such a laminate, a base layer is disposed on the surface of the release layer opposite the release treatment layer, and an adhesive layer is disposed on the surface of the base layer opposite the release layer. In the laminate, the release layer and the base layer are preferably directly bonded together, and the base layer and the adhesive layer are preferably directly bonded together.

The laminate may contain layers other than the release layer, the base layer, and the adhesive layer, so long as the effects of the present invention are not impaired, and the laminate may also be formed of only a release layer provided with a release treatment layer, a base layer, and an adhesive layer. Thus, the adhesive sheet of the present invention may be formed, for example, of only a laminate.

The adhesive sheet of the present invention is a single-sided adhesive sheet, not a double-sided adhesive sheet.

The adhesive sheet of the present invention is a long sheet, and there are no particular limitations on the dimensions such as width and thickness, and it can be the same size as known adhesive sheets, for example.

The adhesive sheet of the present invention can be in the form of a roll. The form of such a roll is not particularly limited, and for example, the roll may be formed by rolling the adhesive sheet of the present invention around a cylindrical core material. In this case, the winding direction of the adhesive sheet of the present invention around the cylindrical core material is not limited, and for example, the adhesive sheet of the present invention may be rolled around the cylindrical core material so that the release layer of the adhesive sheet of the present invention is on the outside, or vice versa. For example, when the adhesive sheet of the present invention is rolled around the cylindrical core material so that the release layer of the adhesive sheet of the present invention is on the outside, the surface of the release layer on the release treatment layer side of the roll overlaps with the adhesive layer, making it easy to stretch the adhesive sheet from the roll.

In the wound body of the present invention, the type and size of the cylindrical core material are not particularly limited, and a wide range of known cylindrical core materials can be used.

The adhesive sheet of the present invention is formed with the laminate, so that even when used as a rolled body, it is less likely to slip when applied. In addition, the adhesive sheet of the present invention is formed with the laminate, so that it is less likely to wrinkle after application and has excellent conformability to curved surfaces. Therefore, by using the adhesive sheet of the present invention, not only can a human work easily be performed, but even when a robot performs the application work, it is less likely to slip when applied. In other words, the adhesive sheet of the present invention can be suitably used for robot application.

The adhesive sheet of the present invention preferably has a peak-to-peak distance of 5 mm or less in the peel SS curve obtained when the adhesive layer is adhered to the peel layer and then peeled off. In this case, wrinkles are less likely to occur after the adhesive sheet is applied to an object, which tends to improve workability, particularly continuous workability.

Here, the mountain-to-mountain distance of the peel SS curve can be measured by the following <Peel Measurement>.
<Peeling measurement>
A 20 mm wide laminate is prepared, and only the release layer is peeled off from the laminate to separate the release layer and the composite layer having the base layer and the adhesive layer. The surface of the peeled release layer opposite the release treatment layer is attached to the surface of a SUS plate with double-sided adhesive tape, and the adhesive layer side of the composite layer is attached to the release layer, and a 2 kg roller is reciprocated twice from one end of the composite layer to the other end to perform a pressure bonding process. 24 hours after the pressure bonding process, the distance between each apex in the range of 20 mm to 50 mm from the peel start point is measured in the peel SS curve obtained when one end of the composite layer is peeled off at an angle of 90° at a speed of 1500 mm/min to 50 mm, and the average value of these is taken as the mountain distance of the peel SS curve.

FIG. 2 shows one embodiment of the peel SS curve obtained by the above peel measurement. As shown in FIG. 2, the peel SS curve is a wavy curve. In this wavy curve, the straight-line distance between each vertex (between adjacent vertices) existing in the range of 20 mm to 50 mm from the peel start point as the starting point can be measured with a caliper or the like, and the average value of the straight-line distances can be used as the inter-peak distance of the peel SS curve. For example, the peel SS curve shown in FIG. 2 has a total of seven vertices, so a total of six straight-line distances between adjacent vertices (L ₁ , L ₂ , L ₃ , L ₄ , L ₅ , L ₆ ) are measured and the average value is calculated (however, in FIG. 2 , the total of seven vertices are assumed to exist in the range of 20 mm to 50 mm from the peel start point as the starting point). The point where the dashed line shown in FIG. 2 intersects with the peel SS curve is the starting point.

The shorter the peak-to-peak distance of the peel SS curve of the adhesive sheet of the present invention, the more preferable. The lower limit of the peak-to-peak distance of the peel SS curve is, for example, 0.01 mm, preferably 0.05 mm, and more preferably 0.1 mm.

The adhesive sheet of the present invention preferably has a peel SS curve with a peak-to-peak distance of 5 mm or less when the angle at which one end of the composite layer is peeled off is changed to 135° in the peel measurement. In this case, wrinkles are less likely to occur after the adhesive sheet is attached to an object, and workability, particularly continuous workability, is improved. A peel SS curve can be obtained by the same method as described in <Peel Measurement> above, except for changing the angle to 135°. The shorter the peak-to-peak distance of the peel SS curve when the angle at which one end of the composite layer is peeled off is, the more preferable it is, and the lower limit of the peak-to-peak distance is, for example, 0.01 mm, preferably 0.05 mm, and more preferably 0.1 mm.

In the adhesive sheet of the present invention, the method for adjusting the inter-peak distance of the peel SS curve is not particularly limited, and for example, the inter-peak distance of the peel SS curve can be adjusted by appropriately selecting the type of release layer, for example, the surface tension or elastic modulus of the release layer.

The adhesive sheet of the present invention preferably has a strength of 50 N/24 mm or less at 10% elongation. In this case, the adhesive sheet of the present invention is particularly improved in its ability to conform to curved surfaces, further improving workability.

The adhesive sheet of the present invention preferably has a strength at 10% elongation of 45 N/24 mm or less, and even more preferably has a strength at 10% elongation of 42 N/24 mm or less. The lower limit of the strength at 10% elongation can be, for example, 5 N/24 mm.

In the adhesive sheet of the present invention, the method for adjusting the strength at 10% elongation is not particularly limited, and can be prepared, for example, by appropriately selecting the types of the release layer and base layer. For example, the strength at 10% elongation can be adjusted by appropriately selecting the composition, molecular weight, crosslinking density, thickness, etc. of the materials forming the release layer and base layer.

When the adhesive sheet of the present invention is wound as described above, it is preferable that B>A, where A (N/25 mm) is the adhesive strength between the adhesive layer and the release treatment layer, and B (N/25 mm) is the adhesive strength between the peel layer and the base layer. In this case, when the wound body is unfolded, the adhesive sheet of the present invention can be unfolded as an integrated unit, and there is an advantage that the peel layer and base layer, which are to be peeled off in a later process, can be unfolded without peeling off first. There are no particular limitations on the method for adjusting the values of A and B, and they can be adjusted, for example, by appropriately combining the types of materials of the adhesive layer, release treatment layer, peel layer, and base layer. The values of A and B can be measured in accordance with JIS Z 0237, and specifically, they are measured by the 180° peel method at a test speed of 300 mm/min in an environment of 23°C and 50% RH.

The value of A is preferably 0.005 to 0.1 N/25 mm, and more preferably 0.01 to 0.05 N/25 mm. The value of B is preferably 0.11 to 0.7 N/25 mm, and more preferably 0.15 to 0.4 N/25 mm. B is preferably 7 to 22 times A, and more preferably 8 to 15 times.

The adhesive sheet of the present invention can be used for a variety of purposes, and can be used for various purposes such as repair and joining, for which conventional adhesive sheets have been used. In particular, since the adhesive sheet of the present invention has excellent workability even when applied by a robot, as described above, the adhesive sheet can be applied in places where it is dangerous for humans to work, such as high places, by using robot work in combination. Therefore, for example, the adhesive sheet of the present invention can be suitably used for repairing wind power generation blades.

The method of use (adhesion method) of the adhesive sheet of the present invention is not particularly limited, and it can be used in various ways. For example, an adhesion method using the adhesive sheet of the present invention can include a step of peeling off the release layer of the adhesive sheet after attaching the adhesive sheet to an object. In this step, the adhesive sheet may be in the form of the roll.

The adhesive sheet of the present invention does not require the removal of release paper or the like attached to the adhesive surface when unrolling the adhesive sheet from the roll-shaped core as with conventional adhesive sheets, making application easy even when performed by a fully automated robot, and also making it less likely for the sheet to slip when rolled and less likely to wrinkle after application.

In identifying the inventions encompassed by this disclosure, the configurations (properties, structures, functions, etc.) described in each embodiment of this disclosure may be combined in any way. In other words, this disclosure encompasses all subject matter consisting of all combinations of the combinable configurations described in this specification.

The present invention will be explained in more detail below with reference to examples, but the present invention is not limited to the embodiments of these examples.

Example 1
A laminate was formed by laminating the release layer, the base layer, and the adhesive layer in this order, using Sumiron's "VE-210WBF", a sheet of BASF's "NY585" as the release layer, a sheet of Sekisui Chemical's "NY585" as the base layer, and Sekisui SJ (SJ600) as the adhesive layer. The base layer was formed by extruding "NY585", and the release layer and the adhesive layer were laminated on the obtained base layer having a thickness of 0.4 mm to form a laminate. In forming this laminate, the surface opposite to the silicone-based release treatment layer formed on the release layer was attached to the base layer. The laminate thus obtained was used as an adhesive sheet.

Example 2
An adhesive sheet was obtained in the same manner as in Example 1, except that the release layer was changed to Sumiron Corporation's "DE600."

Example 3
An adhesive sheet was obtained in the same manner as in Example 1, except that the release layer was changed to "NOVACEL #4336" (registered trademark).

(Comparative Example 1)
A sheet of "NY585" from BASF was prepared as the base layer, "SJ600" from Sekisui Chemical as the adhesive layer, and "#5001" from Lintec as the release paper, and a laminate was formed by laminating the base layer, adhesive layer, and release paper in this order. The base layer was formed by extruding "NY585", and the release paper and adhesive layer were laminated on the obtained base layer to form a laminate. The laminate thus obtained was used as an adhesive sheet.

(Physical property measurements)
The adhesive sheets obtained in each of the Examples and Comparative Examples were used as samples to measure the strength at 10% elongation and the mountain-to-mountain distance of the peel SS curve by the following methods.

<Strength at 10% elongation>
The adhesive sheets obtained in each of the Examples and Comparative Examples were cut to a width of 24 mm and a length of 80 mm, and marked lines were written on the adhesive sheets so that the distance between the marked lines was 50 mm. The marked lines were chucked using a tensile tester, Tensilon RTF-1310, manufactured by A&D, and a tensile test was carried out at a speed of 300 mm/min. The strength when the distance between the marked lines reached 55 mm was taken as the strength at 10% elongation.

<Distance between peaks of peeling SS curve 1>
The laminate having a width of 20 mm was prepared, and only the release layer was peeled off from the laminate to separate the release layer and the composite layer having the base layer and the adhesive layer. The surface of the peeled release layer opposite to the release treatment layer was attached to the surface of a SUS plate with a double-sided adhesive tape, and the adhesive layer side of the composite layer was attached to the release layer, and a 2 kg roller was reciprocated twice from one end of the composite layer to the other end to perform a pressure bonding process. 24 hours after the pressure bonding process, the distance between each apex in the range of 20 mm to 50 mm from the peel start point was measured in the peel SS curve obtained when one end of the composite layer was peeled off at an angle of 90° at a speed of 1500 mm/min to 50 mm, and the average value of these was taken as the mountain distance of the peel SS curve.

<Distance between peaks of peeling SS curve 2>
The mountain-to-mountain distance of the peel SS curve was measured in the same manner as in the mountain-to-mountain distance of the peel SS curve 1, except that the composite layer was peeled off at an angle of 135°.

(Evaluation method)
The adhesive sheets obtained in each of the Examples and Comparative Examples were used as samples to measure the strength at 10% elongation and the mountain-to-mountain distance of the peel SS curve by the following methods.

(Rolling slippage, wrinkles, curved surface conformability)
The adhesive sheet was evaluated for slippage, wrinkles, and curved surface conformability using the adherend 50 shown in FIG. 3. FIG. 3 is a schematic diagram showing a part of the adherend 50, where (a) is a front view of the adherend 50, (b) is a side view of the adherend 50, and (c) is a plan view of the adherend 50. That is, FIG. 3(b) shows the shape seen from the solid arrow side of (a), and (c) shows the shape seen from the dashed arrow side of (a). As can be seen from FIG. 3, the adherend 50 mimics a blade shape. As shown in FIG. 3(a), the adhesive sheet 51 was attached along the edge of the adherend 50, while the slippage, wrinkles, and curved surface conformability were evaluated. As shown in FIG. 3(a), the width of the adherend 50 was 400 mm, and as shown in FIGS. 3(b) and (c), the thickness of the adherend 50 was 50 mm.

As the adhesive sheet 51, a roll of adhesive sheet 100 mm wide and 5 m long was prepared by winding it around a cylindrical core (width 100 mm, inner diameter 3 inches). The adhesive sheet 51 was attached to the edge of the adherend 50 along the edge of the adherend 50 so that the end of the adhesive sheet 51 was located at the most distal end 55 of the adherend 50. The adhesive sheet 51 was attached so as to cover the edge of the adherend 50 from the front to the back. Specifically, the widthwise center of the adhesive sheet 51 was pressed against the edge of the adherend 50, and the adhesive sheet 51 was attached while being sufficiently stretched to the most distal end 55 at a speed of 1500 mm/min. Then, both ends of the adhesive sheet in the widthwise direction were smoothed onto the adherend side.

The adhesive sheet 51 was attached to the adherend 50 as described above, and the occurrence of slippage, wrinkles, and curved surface conformability were evaluated. In particular, the occurrence of wrinkles was evaluated by observing the straight portion 52 of the adherend 50 (see FIGS. 3(a) and (b)), and the curved surface conformability was evaluated by observing the curved portion 53 of the adherend 50 (see FIGS. 3(a) and (b)), and the evaluation was performed according to the following criteria. The straight portion 52 was 4700 mm in terms of the length of the adhesive sheet 51, and the curved portion 53 was 320 mm in terms of the length of the adhesive sheet 51. Although the curved portion 53 is not precisely illustrated in FIGS. 3(a) to (c), it was formed on a semicircular arc with a radius of 200 mm in plan view (FIG. 3(a)).
[Winding Misalignment]
◯: No winding deviation occurred.
×: Misalignment occurred in the width direction.
[Wrinkle]
A: No wrinkles were observed.
△: Wrinkles occurred when the flat surface was applied.
[Curved surface conformity]
◯: No wrinkles were observed overall, and the film had excellent curved surface conformability.
Δ: Wrinkles were generated at the tip of the convex portion, and the ability to conform to a curved surface was poor.

Table 1 shows the layer structure, physical properties, and evaluation results of the adhesive sheets obtained in each example and comparative example.

As shown in Table 1, the adhesive sheets obtained in Examples 1 to 3 were less likely to slip when applied, and were also less likely to wrinkle after application, and had excellent conformability to curved surfaces. In contrast, the adhesive sheet obtained in Comparative Example 1 was significantly more likely to slip when applied, and it was not even possible to measure the inter-mountain distance or evaluate wrinkles and conformability to curved surfaces.

A: adhesive sheet 1: release layer 2: base layer 3: adhesive layer 10: laminate 1a: release treatment layer

Claims

The laminate includes a release layer, a base layer, and an adhesive layer laminated in this order,
An adhesive sheet, wherein a release treatment layer is formed on the surface of the release layer opposite to the base layer.
the distance between peaks of a peel SS curve obtained when the adhesive layer is adhered to the release layer and then the adhesive layer is peeled off is 5 mm or less;
2. The adhesive sheet according to claim 1, wherein the peak-to-peak distance of the peel SS curve is measured by the following peel measurement.
<Peeling measurement>
A 20 mm wide laminate is prepared, and only the release layer is peeled off from the laminate to separate the release layer and the composite layer having the base layer and the adhesive layer. The surface of the peeled release layer opposite the release treatment layer is attached to the surface of a SUS plate with double-sided adhesive tape, and the adhesive layer side of the composite layer is attached to the release layer, and a 2 kg roller is reciprocated twice from one end of the composite layer to the other end to perform a pressure bonding process. 24 hours after the pressure bonding process, the distance between each apex in the range of 20 mm to 50 mm from the peel start point is measured in the peel SS curve obtained when one end of the composite layer is peeled off at an angle of 90° at a speed of 1500 mm/min to 50 mm, and the average value of these is taken as the mountain distance of the peel SS curve.
The adhesive sheet according to claim 1, having a strength at 10% elongation of 50 N/24 mm or less.
The adhesive sheet according to claim 1, which has a weak adhesive layer between the release layer and the substrate layer.
The adhesive sheet according to claim 1, which is for robot application.
The adhesive sheet according to claim 1, which is used for repairing wind power generation blades.
A bonding method using the adhesive sheet according to any one of claims 1 to 6,
The adhesive sheet is attached to an object, and then the release layer is peeled off.
A roll in which the adhesive sheet according to any one of claims 1 to 6 is wound around a cylindrical core material.