CN107663426B

CN107663426B - Double-sided adhesive sheet

Info

Publication number: CN107663426B
Application number: CN201710630642.3A
Authority: CN
Inventors: 三井数马; 野中崇弘; 藤田雅人; 樋口直孝
Original assignee: Nitto Denko Corp
Current assignee: Nitto Denko Corp
Priority date: 2016-07-28
Filing date: 2017-07-28
Publication date: 2023-02-21
Anticipated expiration: 2037-07-28
Also published as: TW201809183A; JP2018016727A; CN115746721A; CN107663426A; TWI744347B; JP6870933B2; KR20180013747A; KR102419875B1

Abstract

The present invention relates to a double-sided adhesive sheet. The invention provides a double-sided adhesive sheet with a release liner, which is suitable for easily peeling the release liner, inhibiting local damage or defect of an adhesive layer when the release liner is peeled, and is suitable for efficiently manufacturing. The pressure-sensitive adhesive sheet (X1) as a double-sided pressure-sensitive adhesive sheet of the present invention has a laminated structure including a pressure-sensitive adhesive sheet main body (10) as a double-sided pressure-sensitive adhesive sheet main body and release liners (L1) and (L2). The adhesive sheet main body (10) has at least one adhesive layer (11) and is located between release liners (L1, L2). At least a partial region of the outer peripheral end (11 a) of the pressure-sensitive adhesive layer (11) is located inward in the pressure-sensitive adhesive sheet plane direction from the outer peripheral end (L1 a) of the release liner (L1) and the outer peripheral end (L2 a) of the release liner (L2) and at a position where the distance D between the outer peripheral end (L1 a) of the release liner (L1) and the outer peripheral end (L2 a) of the release liner (L2) is 5 [ mu ] m to 2000 [ mu ] m.

Description

Double-sided adhesive sheet

Technical Field

The present invention relates to a double-sided pressure-sensitive adhesive sheet with a release liner.

Background

In recent years, double-sided adhesive sheets having high transparency have been used in various technical fields. For example, in the field of flat panel displays, optical double-sided adhesive sheets are used for manufacturing display devices and the like. Specifically, a display device such as a liquid crystal display or an input device such as a touch panel has a laminated structure portion including various substrates or film bodies, and a transparent double-sided adhesive sheet is sometimes used in order to bond predetermined members adjacent to each other in the laminated structure or to fill a gap between adjacent members. Such double-sided pressure-sensitive adhesive sheets are described in, for example, patent documents 1 to 3 below.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2012-188595

Patent document 2: japanese laid-open patent publication No. 2015-200698

Patent document 3: japanese patent laid-open publication No. 2016-26321

Disclosure of Invention

Problems to be solved by the invention

Double-sided adhesive sheets are sometimes manufactured and shipped with both adhesive sides covered with a pair of release liners. Such a double-sided pressure-sensitive adhesive sheet with a release liner is sometimes required to be easily peeled by manual work from the viewpoint of work efficiency, etc. since each release liner is peeled from the main body of the double-sided pressure-sensitive adhesive sheet at a predetermined timing when it is used.

In addition, conventionally, when one release liner is peeled from a double-sided adhesive sheet main body having release liners on both adhesive surfaces, a part of the adhesive surface of the double-sided adhesive sheet main body is pulled away by the release liner, and local breakage or defect may occur in the adhesive surface or the adhesive layer.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a release-liner-attached double-sided adhesive sheet which is suitable for facilitating the release operation of a release liner, suppresses local breakage or chipping of an adhesive layer at the time of release of the release liner, and is suitable for efficient production.

Means for solving the problems

A double-sided adhesive sheet provided according to a first aspect of the present invention has a laminated structure including a first release liner, a second release liner, and a double-sided adhesive sheet main body between the first release liner and the second release liner. The double-sided adhesive sheet main body has at least one adhesive layer. Such a double-sided adhesive sheet main body may be composed of a single adhesive layer, or may have a laminated structure including two adhesive layers forming both adhesive surfaces and a substrate or the like between the adhesive layers. Further, at least a partial region of the outer peripheral end of the pressure-sensitive adhesive layer in the double-sided pressure-sensitive adhesive sheet main body is located at a position 5 μm to 2000 μm inward in the pressure-sensitive adhesive sheet in-plane direction from the outer peripheral end of the first release liner and the outer peripheral end of the second release liner. The pressure-sensitive adhesive sheet in-plane direction means the in-plane direction of the present double-sided pressure-sensitive adhesive sheet or double-sided pressure-sensitive adhesive sheet main body. In the in-plane direction of such an adhesive sheet, at least a partial region of the outer peripheral edge of the pressure-sensitive adhesive layer is located at a distance of 5 to 2000 μm from the nearest outer peripheral edge of the first release liner to the inside of the pressure-sensitive adhesive sheet with respect to the nearest outer peripheral edge of the first release liner, and is located at a distance of 5 to 2000 μm from the nearest outer peripheral edge of the second release liner to the inside of the pressure-sensitive adhesive sheet with respect to the nearest outer peripheral edge of the second release liner.

As described above, at least a partial region of the outer peripheral end of the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet main body with the release liner is located at a position 5 μm to 2000 μm inward from each of the outer peripheral end of the first release liner and the outer peripheral end of the second release liner in the pressure-sensitive adhesive sheet in-plane direction. That is, the outer peripheral end of the adhesive layer of the double-sided adhesive sheet main body is located at a position spaced from the outer peripheral ends of the first and second release liners in the adhesive sheet in-plane direction at least in a part of the region thereof. In the case where the double-sided adhesive sheet main body is constituted by a single adhesive layer, for example, the outer peripheral end of the adhesive layer has a region located at a position spaced from the outer peripheral ends of the first and second release liners in the adhesive sheet in-plane direction in such a manner that a concave shape, for example, is formed at the outer peripheral end of the sheet in a cross section in the thickness direction of the double-sided adhesive sheet. In the case where the double-sided adhesive sheet main body has a laminated structure including two adhesive layers forming both adhesive surfaces and a base material between the adhesive layers, for example, the outer peripheral end of each adhesive layer has a region located at a position spaced from the outer peripheral ends of the first release liner and the second release liner in the inner direction of the adhesive sheet surface. The distance between the outer peripheral edge of the pressure-sensitive adhesive layer and the outer peripheral edge of each release liner in the in-plane direction of the pressure-sensitive adhesive sheet at a position spaced apart from the outer peripheral edge of each release liner in the in-plane direction of the pressure-sensitive adhesive sheet is 5 μm to 2000 μm as described above. When the release liner is peeled off from such a double-sided adhesive sheet, if a portion (outer peripheral end interval portion) where the outer peripheral end of the adhesive layer of the double-sided adhesive sheet main body is located at a position spaced apart from the outer peripheral ends of the first release liner and the second release liner in the adhesive sheet in-plane direction is used, the peeling operation is easily performed. Specifically, in the double-sided adhesive sheet, for example, the fingertip of the worker can easily be brought into contact with the first release liner or the second release liner to be peeled without being in contact with the adhesive layer at the peripheral edge separation portion, and therefore, appropriate deformation for peeling can be easily started on the release liner, and separation of the release liner and the adhesive layer from the edge of the interface between the release liner to be peeled and the adhesive layer can be easily started.

In addition, in the double-sided adhesive sheet, when the release liner is peeled off, the fingertip of the worker can easily contact the first release liner or the second release liner to be peeled off without contacting the adhesive layer. At the same time, at the peripheral edge interval portion of the present double-sided adhesive sheet, as described above, it is easy to initiate appropriate deformation for peeling on the release liner and to initiate separation of the release liner and the adhesive layer from the end of the interface therebetween, which is the object of peeling. In each of these aspects, the present double-sided adhesive sheet, which can be peeled off with the release liner at the peripheral edge separation portion, is suitable in terms of suppressing the partial breakage or defect of the adhesive surface or the adhesive layer caused by the part of the adhesive surface of the double-sided adhesive sheet main body being pulled away by the release liner at the time of peeling off the release liner.

In addition, in the present double-sided adhesive sheet, the distance between the outer peripheral edge of the adhesive layer at a position spaced apart from the outer peripheral edge of each release liner in the in-plane direction of the adhesive sheet and the outer peripheral edge of each release liner in the in-plane direction of the adhesive sheet is 5 μm to 2000 μm as described above. The double-sided adhesive sheet having such a structure is suitable for efficient production. Specifically, the following is described.

First, a double-sided psa sheet raw material for forming the present double-sided psa sheet by punching, cutting, or the like is prepared. The double-sided adhesive sheet stock has a laminated structure including a preliminary first release liner, a preliminary second release liner, and a preliminary double-sided adhesive sheet main body having at least one adhesive layer and located between the preliminary first release liner and the preliminary second release liner. Next, the double-sided pressure-sensitive adhesive sheet material is processed while being subjected to a pressure in the thickness direction thereof, thereby forming a double-sided pressure-sensitive adhesive sheet having a desired overall dimension. The pressure-sensitive adhesive layer as an elastic body in the preliminary double-sided pressure-sensitive adhesive sheet main body of the double-sided pressure-sensitive adhesive sheet material is elastically deformable in response to a pressure force in a state where the material is subjected to the pressure force in the thickness direction, and elastically stretches in the in-plane direction of the material at an elongation rate corresponding to the pressure force, and the material can be elastically expanded (swelled) at the outer peripheral end thereof from between the preliminary first release liner and the preliminary second release liner. Examples of the processing means include blanking and/or cutting. In this processing step, specifically, the double-sided adhesive sheet raw material in a state of being pressurized in the thickness direction is subjected to processing such as punching and/or cutting so that a part or the whole of the outer peripheral edge of the double-sided adhesive sheet is formed into a new shape by the processing to obtain a double-sided adhesive sheet of a target outer dimension. In the double-sided adhesive sheet obtained by releasing the pressure-applied state, the pressure-sensitive adhesive layer is returned from the elastically deformed state to the non-deformed state, and the outer peripheral edge of the double-sided adhesive sheet newly generated in the processing step is retracted inward between the first release liner and the second release liner. That is, in the produced double-sided adhesive sheet, the adhesive layer outer peripheral end has a region located at a position spaced apart from the outer peripheral end of each release liner inward in the adhesive sheet in the in-plane direction. Further, the distance of the gap between the outer peripheral end of each release liner and the outer peripheral end of the adhesive layer, which is generated as a result of utilizing the elastic deformation and the shape recovery thereafter of the adhesive layer, tends to be in the short range of 5 μm to 2000 μm. On the other hand, in order to produce a double-sided psa sheet with a release liner having an outer dimension greater than 5000 μm or more than the double-sided psa sheet main body or the psa layer included therein, for example, after producing a double-sided psa sheet with release liners having the same outer dimension as the double-sided psa sheet main body on both adhesive sides, it is necessary to replace each release liner ( り instead える) with a release liner having an outer dimension greater than the double-sided psa sheet main body by the range described above. However, such a method is not efficient from the viewpoint of material cost and the number of steps. The present double-sided adhesive sheet, in which the distance between the outer peripheral end of the adhesive layer at a position spaced apart from the outer peripheral end of each release liner in the in-plane direction of the adhesive sheet and the outer peripheral end of each release liner in the in-plane direction of the adhesive sheet is 5 μm to 2000 μm, is suitable for efficient production through the above-described process utilizing elastic deformation of the adhesive layer and subsequent shape recovery.

As described above, the double-sided adhesive sheet according to the first aspect of the present invention is suitable for facilitating the operation of peeling the release liner, suppressing local damage or chipping of the adhesive layer at the time of peeling the release liner, and for efficient production. In addition, the present double-sided adhesive sheet in which the distance between the outer peripheral end of the adhesive layer and the outer peripheral end of each release liner at a position spaced from the outer peripheral end of each release liner in the in-plane direction of the adhesive sheet is 5 μm to 2000 μm is suitable for achieving the size required for the double-sided adhesive sheet main body while avoiding the outer dimension of the double-sided adhesive sheet, that is, the outer dimension of the release liner, from greatly exceeding the size of the double-sided adhesive sheet main body and becoming excessively large.

In the first aspect of the present invention, it is preferable that the outer peripheral end of the adhesive layer of the double-sided adhesive sheet main body is located at a position 5 μm to 2000 μm inward from each of the outer peripheral end of the first release liner and the outer peripheral end of the second release liner in the adhesive sheet in-plane direction from the outer peripheral end of the first release liner and the outer peripheral end of the second release liner. That is, the outer peripheral edge of the adhesive layer of the double-sided adhesive sheet main body is located at a position 5 to 2000 μm from the closest outer peripheral edge of the first release liner to the inside of the adhesive sheet with respect to the closest outer peripheral edge of the first release liner and at a position 5 to 2000 μm from the closest outer peripheral edge of the second release liner to the inside of the adhesive sheet with respect to the closest outer peripheral edge of the second release liner over the entire area.

In the first aspect of the present invention, the thickness of the adhesive layer of the double-sided adhesive sheet main body is preferably 25 μm or more. Such a configuration is preferable in that the distance between the outer peripheral end of each release liner and the outer peripheral end of the pressure-sensitive adhesive layer is preferably 5 μm or more at the outer peripheral end separation portion.

In the first aspect of the present invention, it is preferable that the adhesive layer of the double-sided adhesive sheet main body has a storage modulus at 23 ℃ of 1.0X 10 ⁴ Pa or above. Such a configuration is suitable for efficiently producing the double-sided adhesive sheet having the above-described distance between the outer peripheral edge of each release liner and the outer peripheral edge of the pressure-sensitive adhesive layer of 5 to 2000 μm by elastic deformation of the pressure-sensitive adhesive layer and subsequent shape recovery.

A double-sided adhesive sheet according to a second aspect of the present invention has a laminated structure including a first release liner, a second release liner, and a double-sided adhesive sheet main body between the first release liner and the second release liner. The double-sided adhesive sheet main body has a laminated structure including, for example, a first adhesive layer on a first release liner side, a second adhesive layer on a second release liner side, and a base material between the first adhesive layer and the second adhesive layer. At least a partial region of the outer peripheral end of the first adhesive layer is located at a position 5 μm to 2000 μm in the adhesive sheet in-plane direction from the outer peripheral end of the first release liner and the outer peripheral end of the second release liner inward from the outer peripheral end of the first release liner and the outer peripheral end of the second release liner. At least a partial region of the outer peripheral end of the second adhesive layer is located at a position 5 μm to 2000 μm inward from the outer peripheral end of the first release liner and the outer peripheral end of the second release liner in the adhesive sheet in-plane direction from the outer peripheral end of the first release liner and the outer peripheral end of the second release liner. The pressure-sensitive adhesive sheet in-plane direction means the in-plane direction of the present double-sided pressure-sensitive adhesive sheet or double-sided pressure-sensitive adhesive sheet main body. In such an adhesive sheet in-plane direction, at least a partial region of the outer peripheral end of the first adhesive layer is located at a position 5 to 2000 μm away from the nearest outer peripheral end of the first release liner inward of the adhesive sheet, and at a position 5 to 2000 μm away from the nearest outer peripheral end of the second release liner inward of the adhesive sheet. At the same time, in the adhesive sheet in-plane direction, at least a partial region of the outer peripheral end of the second adhesive layer is located at a distance of 5 to 2000 μm from the nearest outer peripheral end of the first release liner to the inside of the adhesive sheet with respect to the nearest outer peripheral end of the first release liner, and at a distance of 5 to 2000 μm from the nearest outer peripheral end of the second release liner to the inside of the adhesive sheet with respect to the nearest outer peripheral end of the second release liner.

As described above, at least a partial region of the outer peripheral end of each pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer, second pressure-sensitive adhesive layer) of the double-sided pressure-sensitive adhesive sheet main body with the release liner is located at a position 5 μm to 2000 μm away from the outer peripheral end of the first release liner and the outer peripheral end of the second release liner from the inner side of each of the outer peripheral end of the first release liner and the outer peripheral end of the second release liner in the pressure-sensitive adhesive sheet in the in-plane direction. That is, at least a partial region of the outer peripheral end of each pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet main body is located at a position spaced from the outer peripheral ends of the first and second release liners in the pressure-sensitive adhesive sheet in-plane direction. The distance in the in-plane direction of the adhesive sheet between the first adhesive layer outer peripheral end and each release liner outer peripheral end at a position spaced apart from each release liner outer peripheral end in the in-plane direction of the adhesive sheet, and the distance in the in-plane direction of the adhesive sheet between the second adhesive layer outer peripheral end and each release liner outer peripheral end at a position spaced apart from each release liner outer peripheral end in the in-plane direction of the adhesive sheet are each 5 μm to 2000 μm as described above. When the release liner is peeled off from such a double-sided adhesive sheet, if a portion (first outer peripheral end spacing portion) where the outer peripheral end of the first adhesive layer of the double-sided adhesive sheet main body is located at a position spaced apart from the outer peripheral ends of the first release liner and the second release liner in the adhesive sheet in-plane direction and a portion (second outer peripheral end spacing portion) where the outer peripheral end of the second adhesive layer is located at a position spaced apart from the outer peripheral ends of the first release liner and the second release liner in the adhesive sheet in-plane direction are used, the peeling operation is facilitated. Specifically, in the first outer peripheral end interval portion, for example, it is easy for the fingertip of the operator to contact the first release liner to be peeled positioned on the first pressure-sensitive adhesive layer side, for example, without contacting the first pressure-sensitive adhesive layer, and therefore, it is easy to start appropriate deformation for peeling on the first release liner and start separation of the first release liner and the first pressure-sensitive adhesive layer from the end of the interface therebetween. In addition, in the second peripheral edge separation portion, for example, the fingertip of the worker is likely to contact the second release liner to be released on the second pressure-sensitive adhesive layer side, for example, without contacting the second pressure-sensitive adhesive layer, and therefore, it is likely that appropriate deformation for releasing is started on the second release liner, and separation of the second release liner and the second pressure-sensitive adhesive layer is started from the end portion of the interface therebetween. In this way, the present double-sided adhesive sheet is easy to peel the release liner from the double-sided adhesive sheet main body by, for example, manual work.

In addition, in the double-sided adhesive sheet, when the release liner is peeled off at the interval between the outer peripheral ends thereof as described above, it is easy for the operator's fingertips or the like to contact the release liner to be peeled off without contacting the adhesive layer. At the same time, at the respective outer peripheral end intervals of the double-sided adhesive sheet, as described above, appropriate deformation for peeling is easily started on the release liner, and separation of the release liner and the adhesive layer to be peeled from each other is started from the end of the interface between the release liner and the adhesive layer. These features are each suitable for the present double-sided adhesive sheet in which the release liner can be peeled off at each peripheral edge separation portion, in terms of suppressing the adhesive surface or the adhesive layer from being partially broken or chipped due to a part of the adhesive surface of the double-sided adhesive sheet main body being pulled away by the release liner when the release liner is peeled off.

In addition, in the present double-sided adhesive sheet, the distance in the in-plane direction of the adhesive sheet between the first adhesive layer outer peripheral end located at a position spaced apart from the outer peripheral end of each release liner in the in-plane direction of the adhesive sheet and the outer peripheral end of each release liner, and the distance in the in-plane direction of the adhesive sheet between the second adhesive layer outer peripheral end located at a position spaced apart from the outer peripheral end of each release liner in the in-plane direction of the adhesive sheet and the outer peripheral end of each release liner are each 5 μm to 2000 μm as described above. The double-sided adhesive sheet having such a structure is suitable for efficient production. Specifically, the following is described.

First, a double-sided psa sheet raw material for forming the present double-sided psa sheet by punching, cutting, or the like is prepared. The double-sided adhesive sheet stock has a laminated structure including a preliminary first release liner, a preliminary second release liner, and a preliminary double-sided adhesive sheet main body located between the preliminary first release liner and the preliminary second release liner. The preparatory double-sided adhesive sheet main body has a laminated structure including, for example, a first adhesive layer on the preparatory first release liner side, a second adhesive layer on the preparatory second release liner side, and a base material between the first adhesive layer and the second adhesive layer. Next, the double-sided adhesive sheet material is processed while being subjected to a pressure in the thickness direction thereof, thereby forming a double-sided adhesive sheet having a target outer dimension. In a state where the double-sided adhesive sheet raw material is subjected to a pressure force in the thickness direction, each adhesive layer as an elastic body in the preliminary double-sided adhesive sheet main body of the raw material is elastically deformed in accordance with the pressure force, elastically stretched in the in-plane direction of the raw material at an elongation rate in accordance with the pressure force, and can be formed in a state of being elastically expanded from between the preliminary first release liner or the preliminary second release liner and the base material of the preliminary double-sided adhesive sheet main body at the outer peripheral end of the raw material. Examples of the processing means include blanking and/or cutting. In this processing step, specifically, the double-sided adhesive sheet raw material in a state of being pressurized in the thickness direction is subjected to processing such as punching and/or cutting so that a part or the whole of the outer peripheral edge of the double-sided adhesive sheet is formed into a new shape by the processing to obtain a double-sided adhesive sheet of a target outer dimension. In the double-sided adhesive sheet obtained by releasing the pressure-applied state, each adhesive layer is restored from the elastically deformed state to the non-deformed state, and the outer peripheral edge of the double-sided adhesive sheet newly generated in the processing step is set back inward between the first release liner or the second release liner and the substrate. That is, in the produced double-sided adhesive sheet, the first adhesive layer outer peripheral end has a region located at a position spaced apart from each release liner outer peripheral end inward in the adhesive sheet in-plane direction, and the second adhesive layer outer peripheral end has a region located at a position spaced apart from each release liner outer peripheral end inward in the adhesive sheet in-plane direction. Further, the distance of the interval between the outer peripheral end of each release liner and the outer peripheral end of the pressure-sensitive adhesive layer (first pressure-sensitive adhesive layer outer peripheral end, second pressure-sensitive adhesive layer outer peripheral end) generated as a result of utilizing the elastic deformation and the shape recovery thereafter of the pressure-sensitive adhesive layer tends to be in the short range of 5 μm to 2000 μm. On the other hand, in order to produce a double-sided psa sheet with a release liner having an outer dimension greater than 5000 μm or more than the double-sided psa sheet main body or the psa layer included therein, for example, after producing a double-sided psa sheet with release liners having the same outer dimension as the double-sided psa sheet main body on both adhesive sides, it is necessary to replace each release liner ( り instead える) with a release liner having an outer dimension greater than the double-sided psa sheet main body by the range described above. However, such a method is not efficient from the viewpoint of material cost and the number of steps. The present double-sided adhesive sheet, in which the separation distance in the in-plane direction of the adhesive sheet between the first adhesive layer outer peripheral end located at a position spaced from each release liner outer peripheral end in the in-plane direction of the adhesive sheet and each release liner outer peripheral end, and the separation distance in the in-plane direction of the adhesive sheet between the second adhesive layer outer peripheral end located at a position spaced from each release liner outer peripheral end in the in-plane direction of the adhesive sheet and each release liner outer peripheral end, are each 5 μm to 2000 μm, is suitable for efficient production through the above-described process utilizing elastic deformation of the adhesive layer and subsequent shape recovery.

As described above, the double-sided adhesive sheet according to the second aspect of the present invention is suitable for facilitating the operation of peeling the release liner, suppressing local damage or chipping of the adhesive layer at the time of peeling the release liner, and for efficient production. In addition, the present double-sided adhesive sheet in which the distance between the first adhesive layer outer peripheral end located at a position spaced from each release liner outer peripheral end in the adhesive sheet in-plane direction and each release liner outer peripheral end and the distance between the second adhesive layer outer peripheral end located at a position spaced from each release liner outer peripheral end in the adhesive sheet in-plane direction and each release liner outer peripheral end are each 5 μm to 2000 μm is suitable for achieving the size required for the double-sided adhesive sheet main body while avoiding the outer dimension of the double-sided adhesive sheet, that is, the outer dimension of the release liner, from greatly exceeding the size of the double-sided adhesive sheet main body and becoming excessively large.

In the second aspect of the present invention, it is preferable that the outer peripheral end of the first adhesive layer of the double-sided adhesive sheet main body is located at a position 5 μm to 2000 μm inward from each of the outer peripheral end of the first release liner and the outer peripheral end of the second release liner in the adhesive sheet in-plane direction from the outer peripheral end of the first release liner and the outer peripheral end of the second release liner. That is, the outer peripheral edge of the first adhesive layer of the double-sided adhesive sheet main body is located at a position 5 to 2000 μm away from the closest outer peripheral edge of the first release liner toward the inside of the adhesive sheet with respect to the closest outer peripheral edge of the first release liner over the entire area, and is located at a position 5 to 2000 μm away from the closest outer peripheral edge of the second release liner toward the inside of the adhesive sheet with respect to the closest outer peripheral edge of the second release liner.

In the second aspect of the present invention, it is preferable that the outer peripheral end of the second adhesive layer of the double-sided adhesive sheet main body is located at a position 5 μm to 2000 μm inward from each of the outer peripheral end of the first release liner and the outer peripheral end of the second release liner in the adhesive sheet in-plane direction from the outer peripheral end of the first release liner and the outer peripheral end of the second release liner. That is, the outer peripheral edge of the second adhesive layer of the double-sided adhesive sheet main body is located at a position 5 to 2000 μm away from the nearest outer peripheral edge of the first release liner toward the inside of the adhesive sheet with respect to the nearest outer peripheral edge of the first release liner and at a position 5 to 2000 μm away from the nearest outer peripheral edge of the second release liner toward the inside of the adhesive sheet with respect to the nearest outer peripheral edge of the second release liner over the entire area.

In the second aspect of the present invention, the thickness of the first pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet main body is preferably 25 μm or more. Such a configuration is preferable in that the distance between the outer peripheral end of each release liner and the outer peripheral end of the first pressure-sensitive adhesive layer is preferably 5 μm or more at the first outer peripheral end separation portion. The thickness of the second pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet main body is preferably 25 μm or more. Such a configuration is preferable in terms of ensuring that the distance between the outer peripheral end of each release liner and the outer peripheral end of the second pressure-sensitive adhesive layer is 5 μm or more at the second outer peripheral end separation portion.

In the second aspect of the present invention, it is preferable that the first adhesive layer of the double-sided adhesive sheet main body has a storage modulus of 1.0 × 10 at 23 ℃ ⁴ Pa or above. Such a configuration is suitable for efficiently manufacturing the double-sided adhesive sheet having the above-described separation distance between the outer peripheral end of each release liner and the outer peripheral end of the first adhesive layer of 5 μm to 2000 μm by utilizing elastic deformation and subsequent shape recovery of the first adhesive layer. The storage modulus at 23 ℃ of the second adhesive layer of the double-sided adhesive sheet main body is preferably 1.0X 10 ⁴ Pa or above. Such a configuration is suitable for efficiently producing the double-sided adhesive sheet having the aforementioned distance between the outer peripheral edge of each release liner and the outer peripheral edge of the second adhesive layer of 5 to 2000 μm, by utilizing elastic deformation and subsequent shape recovery of the second adhesive layer.

Drawings

Fig. 1 is a partial sectional view of a double-sided adhesive sheet according to an embodiment of the present invention.

Fig. 2 is a partially enlarged cross-sectional view of the double-sided adhesive sheet shown in fig. 1.

Fig. 3 is a partial sectional view of a double-sided adhesive sheet according to an embodiment of the present invention.

Fig. 4 is a partially enlarged cross-sectional view of the double-sided adhesive sheet shown in fig. 3.

Reference numerals

X1, X2 adhesive sheet (double-sided adhesive sheet)

10. 20 adhesive sheet main body (double-sided adhesive sheet main body)

11. Adhesive layer

21. Adhesive layer (first adhesive layer)

22. Adhesive layer (second adhesive layer)

11a, 21a, 22a peripheral end

23. Base material

L1 Release liner (first Release liner)

L2 Release liner (second Release liner)

Outer peripheral ends of L1a and L2a

Detailed Description

Fig. 1 is a partial sectional view of an adhesive sheet X1 as a double-sided adhesive sheet with a release liner according to an embodiment of the present invention. The adhesive sheet X1 has a laminated structure including an adhesive sheet main body 10 as a double-sided adhesive sheet main body and release liners L1 and L2. The adhesive sheet main body 10 is located between the release liners L1 and L2, and is formed of an adhesive layer 11. The psa sheet body 10 or the psa layer 11 has psa surfaces 11',11' that can be adhered to an adherend, and in this embodiment has optical transparency. Such a pressure-sensitive adhesive sheet main body 10 is, for example, an optical double-sided pressure-sensitive adhesive sheet that can be used for manufacturing a flat panel display or the like. A display device such as a liquid crystal display or an input device such as a touch panel has a laminated structure portion including various substrates or film bodies, and the adhesive sheet main body 10 can be used as an optical double-sided adhesive sheet for bonding predetermined members adjacent to each other in the laminated structure or as an optical double-sided adhesive sheet for filling a gap between adjacent members. The pressure-sensitive adhesive sheet X1 is a release-liner-equipped double-sided pressure-sensitive adhesive sheet with release liners L1 and L2 for covering the pressure-sensitive adhesive surfaces 11',11' of the pressure-sensitive adhesive sheet main body 10.

The adhesive sheet main body 10 or the adhesive layer 11 in the adhesive sheet X1 contains an adhesive as a main agent. The main agent is a component having the largest weight ratio among the components contained. The adhesive layer 11 contains, for example, at least one selected from the group consisting of an acrylic polymer as an acrylic adhesive, polyurethane as a polyurethane-based adhesive, a silicone-based adhesive, and a rubber-based adhesive. From the viewpoint of achieving both the adhesion of a degree required for the adhesive layer of the double-sided adhesive sheet and high transparency, an acrylic polymer is preferably used as the adhesive in the adhesive layer 11.

When the pressure-sensitive adhesive layer 11 contains an acrylic polymer as an acrylic pressure-sensitive adhesive, the acrylic polymer preferably contains monomer units derived from an alkyl acrylate having a linear or branched alkyl group and/or an alkyl methacrylate having a linear or branched alkyl group as the largest main monomer unit in terms of weight ratio. Hereinafter, "(meth) acrylic acid" means "acrylic acid" and/or "methacrylic acid".

Examples of the alkyl (meth) acrylate having a linear or branched alkyl group as a monomer unit for forming the acrylic polymer, that is, the alkyl (meth) acrylate having a linear or branched alkyl group contained in a monomer component for forming the acrylic polymer include: alkyl (meth) acrylates having a linear or branched alkyl group having 1 to 20 carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate, nonadecyl (meth) acrylate, and eicosyl (meth) acrylate. As the alkyl (meth) acrylate used for the acrylic polymer, one kind of alkyl (meth) acrylate may be used, or two or more kinds of alkyl (meth) acrylates may be used. In the present embodiment, as the alkyl (meth) acrylate used for the acrylic polymer, at least one selected from the group consisting of n-butyl acrylate, 2-ethylhexyl acrylate, and isostearyl acrylate is preferably used.

The proportion of the monomer unit derived from the alkyl (meth) acrylate having a linear or branched alkyl group in the acrylic polymer is preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, and more preferably 90% by weight or more. That is, the proportion of the alkyl (meth) acrylate in the monomer component composition of the raw material for forming the acrylic polymer is preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, and more preferably 90% by weight or more. The acrylic polymer has a monomer unit structure derived from a monomer component composition having such a ratio of the alkyl (meth) acrylate. This configuration of the proportion of the alkyl (meth) acrylate having a linear or branched alkyl group is suitable in that the pressure-sensitive adhesive layer 11 containing the acrylic polymer appropriately exhibits basic characteristics such as adhesiveness of the acrylic polymer as an acrylic pressure-sensitive adhesive.

The acrylic polymer contained in the pressure-sensitive adhesive layer 11 may contain a monomer unit derived from an alicyclic monomer. Examples of the alicyclic monomer used as a monomer unit for forming an acrylic polymer, that is, the alicyclic monomer contained in a monomer component for forming the acrylic polymer include: cycloalkyl (meth) acrylate, (meth) acrylate having a bicyclic hydrocarbon ring, and (meth) acrylate having a tricyclic or higher hydrocarbon ring. Examples of cycloalkyl (meth) acrylates include: cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, and cyclooctyl (meth) acrylate. Examples of the (meth) acrylate having a bicyclic hydrocarbon ring include: bornyl (meth) acrylate and isobornyl (meth) acrylate. Examples of the (meth) acrylate having a hydrocarbon ring having three or more rings include: tetrahydrodicyclopentadiene (meth) acrylate, tetrahydrodicyclopentadiene oxyethyl (meth) acrylate, tetrahydrotricyclopentadienyl (meth) acrylate, 1-adamantyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, and 2-ethyl-2-adamantyl (meth) acrylate. As the alicyclic monomer used for the acrylic polymer, one alicyclic monomer may be used, or two or more alicyclic monomers may be used. In the present embodiment, as the alicyclic monomer used for the acrylic polymer, at least one selected from the group consisting of cyclohexyl acrylate, cyclohexyl methacrylate, isobornyl acrylate and isobornyl methacrylate is preferably used.

From the viewpoint of achieving appropriate flexibility in the pressure-sensitive adhesive layer 11 formed by containing the acrylic polymer, the proportion of the monomer unit derived from the alicyclic monomer in the acrylic polymer is preferably 5 to 60% by weight, more preferably 10 to 50% by weight, and even more preferably 12 to 40% by weight.

The acrylic polymer contained in the pressure-sensitive adhesive layer 11 may contain a monomer unit derived from a hydroxyl group-containing monomer. The hydroxyl group-containing monomer is a monomer having at least one hydroxyl group in the monomer unit. When the acrylic polymer in the pressure-sensitive adhesive layer 11 contains a hydroxyl group-containing monomer unit, the pressure-sensitive adhesive layer 11 can easily obtain adhesiveness and appropriate cohesive force.

As the hydroxyl group-containing monomer of the monomer unit for forming the acrylic polymer, that is, as the hydroxyl group-containing monomer contained in the monomer component for forming the acrylic polymer, for example, there can be mentioned: hydroxyl group-containing (meth) acrylate, vinyl alcohol and allyl alcohol. Examples of the hydroxyl group-containing (meth) acrylate include: 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, hydroxyoctyl (meth) acrylate, hydroxydecyl (meth) acrylate, hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl (meth) acrylate. As the hydroxyl group-containing monomer used for the acrylic polymer, one kind of hydroxyl group-containing monomer may be used, or two or more kinds of hydroxyl group-containing monomers may be used. In the present embodiment, as the hydroxyl group-containing monomer used for the acrylic polymer, at least one selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate and 4-hydroxybutyl methacrylate is preferably used.

The proportion of the monomer unit derived from the hydroxyl group-containing monomer in the acrylic polymer is preferably 1% by weight or more, more preferably 2% by weight or more, more preferably 3% by weight or more, more preferably 7% by weight or more, more preferably 10% by weight or more, and more preferably 15% by weight or more. The proportion of the monomer unit derived from the hydroxyl group-containing monomer in the acrylic polymer is preferably 35% by weight or less, and more preferably 30% by weight or less. These configurations regarding the proportion of the hydroxyl group-containing monomer are suitable for achieving adhesiveness and appropriate cohesive force in the pressure-sensitive adhesive layer 11 formed by containing the acrylic polymer.

The acrylic polymer contained in the pressure-sensitive adhesive layer 11 may contain a monomer unit derived from a nitrogen atom-containing monomer. The nitrogen atom-containing monomer is a monomer having at least one nitrogen atom in the monomer unit. When the acrylic polymer in the pressure-sensitive adhesive layer 11 contains a nitrogen atom-containing monomer unit, the pressure-sensitive adhesive layer 11 can easily obtain hardness and good adhesion reliability.

Examples of the nitrogen atom-containing monomer used for forming the monomer unit of the acrylic polymer, that is, the nitrogen atom-containing monomer contained in the monomer component used for forming the acrylic polymer include: n-vinyl cyclic amides and (meth) acrylamides. Examples of the N-vinylcycloamide of the nitrogen atom-containing monomer include: n-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-morpholone, N-vinyl-2-caprolactam, N-vinyl-1,3-

Oxazin-2-one and N-vinyl-3,5-morpholinodione. Examples of the (meth) acrylamides containing a nitrogen atom monomer include: (meth) acrylamide, N-ethyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N-N-butyl (meth) acrylamide, N-octyl (meth) acrylamide, N-dimethyl (meth) acrylamide, N-diethyl (meth) acrylamide, N-dipropyl (meth) acrylamide, and N, N-diisopropyl (meth) acrylamide. As the nitrogen atom-containing monomer used for the acrylic polymer, one nitrogen atom-containing monomer may be used, or two or more nitrogen atom-containing monomers may be used. In the present embodiment, N-vinyl-2-pyrrolidone is preferably used as the nitrogen atom-containing monomer used for the acrylic polymer.

The pressure-sensitive adhesive layer 11 formed by containing the acrylic polymer preferably has a proportion of a monomer unit derived from a nitrogen atom-containing monomer of 1 wt% or more, more preferably 3 wt% or more, and still more preferably 5 wt% or more, from the viewpoint of achieving appropriate hardness, adhesiveness, and transparency. In the pressure-sensitive adhesive layer 11 formed by containing the acrylic polymer, the proportion of the monomer unit derived from the nitrogen atom-containing monomer in the acrylic polymer is preferably 30% by weight or less, more preferably 25% by weight or less, from the viewpoint of achieving sufficient transparency and from the viewpoint of suppressing excessive hardening and achieving good adhesion reliability.

The acrylic polymer contained in the pressure-sensitive adhesive layer 11 may contain a monomer unit derived from a carboxyl group-containing monomer. A carboxyl group-containing monomer is a monomer having at least one carboxyl group within the monomer unit. When the acrylic polymer in the pressure-sensitive adhesive layer 11 contains a carboxyl group-containing monomer unit, the pressure-sensitive adhesive layer 11 may have good adhesion reliability.

Examples of the carboxyl group-containing monomer used for forming the monomer unit of the acrylic polymer, that is, the carboxyl group-containing monomer contained in the monomer component used for forming the acrylic polymer include: (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid. As the carboxyl group-containing monomer used for the acrylic polymer, one kind of carboxyl group-containing monomer may be used, or two or more kinds of carboxyl group-containing monomers may be used. In the present embodiment, acrylic acid is preferably used as the carboxyl group-containing monomer for the acrylic polymer.

From the viewpoint of ensuring good adhesion reliability by obtaining the contribution of the interaction between the polar group and the carboxyl group in the case where the polar group is present on the surface of the adherend in the pressure-sensitive adhesive layer 11 formed containing the acrylic polymer, the proportion of the monomer unit derived from the carboxyl group-containing monomer in the acrylic polymer is preferably 0.1% by weight or more, more preferably 0.5% by weight or more. From the viewpoint of suppressing excessive hardening of the pressure-sensitive adhesive layer 11 formed by containing the acrylic polymer and achieving good adhesion reliability, the proportion of the monomer unit derived from the carboxyl group-containing monomer in the acrylic polymer is preferably 20% by weight or less, and more preferably 15% by weight or less.

The acrylic polymer contained in the pressure-sensitive adhesive layer 11 may have a crosslinked structure derived from a polyfunctional (meth) acrylate as a copolymerizable crosslinking agent. As the polyfunctional (meth) acrylate, for example, there may be mentioned: 1,6-hexanediol di (meth) acrylate, butanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethane tri (meth) acrylate, allyl (meth) acrylate, and vinyl (meth) acrylate. As the polyfunctional (meth) acrylate used for the acrylic polymer, one polyfunctional (meth) acrylate may be used, or two or more polyfunctional (meth) acrylates may be used. In the present embodiment, as the polyfunctional (meth) acrylate used for the acrylic polymer, at least one selected from the group consisting of 1,6-hexanediol diacrylate, dipentaerythritol hexaacrylate, and trimethylolpropane triacrylate is preferably used.

The proportion of the monomer unit derived from the polyfunctional (meth) acrylate in the acrylic polymer is preferably 0.01% by weight or more, more preferably 0.03% by weight or more, more preferably 0.05% by weight or more, and more preferably 0.1% by weight or more. The proportion of the monomer unit derived from the polyfunctional (meth) acrylate in the acrylic polymer is preferably 1% by weight or less, and more preferably 0.5% by weight or less. These configurations regarding the proportion of the polyfunctional (meth) acrylate are suitable in order to achieve appropriate hardness and adhesiveness in the pressure-sensitive adhesive layer 11 formed containing the acrylic polymer.

When the pressure-sensitive adhesive layer 11 contains the acrylic polymer as described above as the pressure-sensitive adhesive, the content of the acrylic polymer in the pressure-sensitive adhesive layer 11 is, for example, 85% by weight to 100% by weight.

The pressure-sensitive adhesive layer 11 may contain, for example, an acrylic oligomer having a different raw material monomer composition from the acrylic polymer, from the viewpoint of achieving high adhesiveness at room temperature. When the pressure-sensitive adhesive layer 11 contains such an acrylic oligomer, the content of the acrylic oligomer in the pressure-sensitive adhesive layer 11 is, for example, 0.1 to 20 parts by weight per 100 parts by weight of the pressure-sensitive adhesive or the acrylic polymer in the pressure-sensitive adhesive layer 11.

The oligomer is preferably a polymer containing a monomer unit derived from a (meth) acrylate having a cyclic structure (a ring-containing (meth) acrylate) and a monomer unit derived from an alkyl (meth) acrylate having a linear or branched alkyl group.

Examples of the ring-containing (meth) acrylate as the monomer unit for forming the oligomer, that is, the ring-containing (meth) acrylate contained in the monomer component for forming the oligomer include: cycloalkyl (meth) acrylate, (meth) acrylate having a bicyclic hydrocarbon ring, (meth) acrylate having a hydrocarbon ring of three or more rings, and (meth) acrylate having an aromatic ring. Examples of cycloalkyl (meth) acrylates include: cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloheptyl (meth) acrylate, and cyclooctyl (meth) acrylate. Examples of the (meth) acrylate having a bicyclic hydrocarbon ring include: bornyl (meth) acrylate and isobornyl (meth) acrylate. Examples of the (meth) acrylate having a hydrocarbon ring of three or more rings include: tetrahydrodicyclopentadiene (meth) acrylate, tetrahydrodicyclopentadiene oxyethyl (meth) acrylate, tetrahydrotricyclopentadienyl (meth) acrylate, 1-adamantyl (meth) acrylate, 2-methyl-2-adamantyl (meth) acrylate, and 2-ethyl-2-adamantyl (meth) acrylate. Examples of the (meth) acrylate having an aromatic ring include: phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, and benzyl (meth) acrylate. As the ring-containing (meth) acrylate used for the oligomer, one kind of ring-containing (meth) acrylate may be used, or two or more kinds of ring-containing (meth) acrylates may be used. In the present embodiment, as the ring-containing (meth) acrylate for the oligomer, at least one selected from the group consisting of tetrahydrodicyclopentadiene acrylate and tetrahydrodicyclopentadiene methacrylate is preferably used.

From the viewpoint of achieving appropriate flexibility in the pressure-sensitive adhesive layer 11 formed by containing the oligomer, the proportion of the monomer unit derived from the ring-containing (meth) acrylate in the oligomer is preferably 10 to 90% by weight, more preferably 20 to 80% by weight, and still more preferably 35 to 75% by weight.

Examples of the alkyl (meth) acrylate having a linear or branched alkyl group as a monomer unit for forming the oligomer, that is, the alkyl (meth) acrylate having a linear or branched alkyl group as a monomer component for forming the oligomer include: alkyl (meth) acrylates having a linear or branched alkyl group having 1 to 20 carbon atoms such as methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, sec-butyl (meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) acrylate, dodecyl (meth) acrylate, tridecyl (meth) acrylate, tetradecyl (meth) acrylate, pentadecyl (meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, isostearyl (meth) acrylate, nonadecyl (meth) acrylate, and eicosyl (meth) acrylate. As the alkyl (meth) acrylate used for the oligomer, one kind of alkyl (meth) acrylate may be used, or two or more kinds of alkyl (meth) acrylates may be used. In the present embodiment, as the alkyl (meth) acrylate used for the oligomer, methyl methacrylate is preferably used.

From the viewpoint of achieving an appropriate elastic modulus in the pressure-sensitive adhesive layer 11 formed containing the oligomer, the proportion of the monomer unit derived from the alkyl (meth) acrylate having a linear or branched alkyl group in the oligomer is preferably 10 to 90% by weight, more preferably 15 to 80% by weight, and still more preferably 20 to 60% by weight.

The oligomer may contain a monomer unit derived from a carboxyl group-containing monomer, an amide group-containing monomer, an amino group-containing monomer, a cyano group-containing monomer, a sulfonic acid group-containing monomer, a phosphoric acid group-containing monomer, an isocyanate group-containing monomer, or an imide group-containing monomer.

The oligomer has a weight average molecular weight (Mw) of, for example, 1000 to 30000, preferably 1000 to 20000, and more preferably 1500 to 10000. From the viewpoint of ensuring good adhesive strength in the pressure-sensitive adhesive layer 11 formed containing the oligomer, the weight average molecular weight of the oligomer is preferably 1000 or more. On the other hand, the weight average molecular weight of the oligomer is preferably 30000 or less from the viewpoint of securing adhesive force particularly at room temperature in the pressure-sensitive adhesive layer 11 containing the oligomer.

The weight average molecular weight of the oligomer can be measured by a Gel Permeation Chromatography (GPC) method. For example, the weight average molecular weight (Mw) can be determined as a standard polystyrene conversion value under the following measurement conditions using a GPC measurement apparatus (trade name "HLC-8120GPC", manufactured by Tosoh corporation).

Column: TSKgel SuperAWM-H (upstream side, manufactured by Tosoh corporation), TSKgel SuperAW4000 (manufactured by Tosoh corporation), and TSKgel SuperAW2500 (downstream side, manufactured by Tosoh corporation) were connected in series

Column size: each column is

Column temperature (measurement temperature): 40 deg.C

Eluent: tetrahydrofuran (THF)

Flow rate: 0.4 mL/min

Sample injection amount: 20 μ L

Sample concentration: about 2.0g/L (tetrahydrofuran solution)

Standard sample: polystyrene

The detector: differential Refractometer (RI)

The adhesive layer 11 may contain a silane coupling agent. Examples of the silane coupling agent include: gamma-glycidoxypropyltrimethoxysilane, gamma-glycidoxypropyltriethoxysilane, gamma-aminopropyltrimethoxysilane and N-phenylaminopropyltrimethoxysilane. Examples of the silane coupling agent include commercially available products such as "KBM-403" (manufactured by shin-Etsu chemical Co., ltd.). As the silane coupling agent, gamma-glycidoxypropyltrimethoxysilane is preferable.

When the pressure-sensitive adhesive layer 11 contains a silane coupling agent, the content of the silane coupling agent in the pressure-sensitive adhesive layer 11 is preferably 0.01 parts by weight or more, and more preferably 0.02 parts by weight or more, based on 100 parts by weight of the pressure-sensitive adhesive or the acrylic polymer in the pressure-sensitive adhesive layer 11. The content of the silane coupling agent in the pressure-sensitive adhesive layer 11 is preferably 1 part by weight or less, and more preferably 0.5 part by weight or less, based on 100 parts by weight of the acrylic polymer. This configuration regarding the content of the silane coupling agent is suitable for realizing high adhesiveness under humid conditions, particularly high adhesiveness to glass, in the pressure-sensitive adhesive layer 11 formed containing the silane coupling agent.

The adhesive layer 11 may contain an ultraviolet absorber. The ultraviolet absorber is a chemical substance that can efficiently absorb ultraviolet rays and can convert absorbed energy into heat, infrared rays, or the like to be released. Examples of such an ultraviolet absorber include: benzotriazole ultraviolet absorbers, hydroxyphenyl triazine ultraviolet absorbers, salicylate ultraviolet absorbers, benzophenone ultraviolet absorbers, hydroxybenzophenone ultraviolet absorbers and cyanoacrylate ultraviolet absorbers. The pressure-sensitive adhesive layer 11 may contain one kind of ultraviolet absorber, or may contain two or more kinds of ultraviolet absorbers.

Examples of the benzotriazole-based ultraviolet absorber include: 2- (2-hydroxy-5-t-butylphenyl) -2H-benzotriazole (product name "TINUVIN PS", manufactured by BASF corporation), an alkyl ester having 7 to 9 carbon atoms of 3- (2H-benzotriazol-2-yl) -5- (1,1-dimethylethyl) -4-hydroxypropanoic acid (product name "TINUVIN 384-2", manufactured by BASF corporation), a mixture of octyl 3- [ 3-t-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl ] propionate and 2-ethylhexyl 3- [ 3-t-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl ] propionate (product name "TINU109", manufactured by BASF corporation), 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (product name "TINUVIN 900", manufactured by BASF corporation), 2- (2H-benzotriazol-2-yl) -5262 zxft-phenyl 5262-bis (1-phenylethyl) phenol (product name "TINUVIN 63", manufactured by BAS-3- (2H-benzotriazol-2-yl) -3- (3-4-hydroxy-5-phenyl) propionate ″, manufactured by BASF-5 ″, manufactured by BASF corporation), and a reaction product of methyl propionate and polyethylene glycol 300 (trade name "TINUVIN 1130", manufactured by basf), 2- (2H-benzotriazol-2-yl) P-cresol (trade name "TINUVIN P", manufactured by basf), 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol (trade name "TINUVIN 234", manufactured by basf), 2- [ 5-chloro-2H-benzotriazol-2-yl ] -4-methyl-6-tert-butylphenol (trade name "TINUVIN326", manufactured by basf), 2- (2H-benzotriazol-2-yl) -3562 zxft-butylphenol (trade name "TINUVIN 328", manufactured by basf corporation), 2- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol (trade name "TINUVIN 329", manufactured by basf corporation), 2,2' -methylenebis [6- (2H-benzotriazol-2-yl) -4- (1,1,3,3-tetramethylbutyl) phenol ] (trade name "TINUVIN 360", manufactured by basf corporation), 2- (2H-benzotriazol-2-yl) -6-dodecyl-4-methylphenol (trade name "TINUVIN 571", manufactured by basf corporation), 2- [ 2-hydroxy-3- (3,4,5,6-tetrahydrophthalimidomethyl) -5-methylphenyl ] benzotriazole (trade name "Sumisorb 250", manufactured by Sumitomo chemical Co., ltd.) and 2,2' -methylenebis [6- (2H-benzotriazol-2-yl) -4-tert-octylphenol ] (trade name "ADK STAB LA-31", manufactured by Aidick Co., ltd.).

Examples of hydroxyphenyl triazine ultraviolet absorbers include: a reaction product of 2- (4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl) -5-hydroxyphenol with [ (alkyloxy) methyl group having 10 to 16 carbon atoms ] ethylene oxide (trade name "TINUVIN 400", manufactured by basf corporation), a reaction product of 2- [4,6-bis (2,4-dimethylphenyl) -1,3,5-triazin-2-yl ] -5- [3- (dodecyloxy) -2-hydroxypropoxy ] phenol), 2- (2,4-dihydroxyphenyl) -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine with 2-ethylhexyl glycidate (trade name "TINUVIN405", basf corporation), 2,4-bis (2-hydroxy-4-butoxyphenyl) -6- (2,4-dibutoxyphenyl) -1,3,5-triazine (trade name "TINUVIN 460", manufactured by basf corporation), 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5-hexyloxyphenol (trade name "TINUVIN 1577", manufactured by basf corporation), 2- (4,6-diphenyl-1,3,5-triazin-2-yl) -5- [2- (2-ethylhexoyloxy) ethoxy ] phenol (trade name "ADK STAB LA-46", ai Dike, manufactured by kakkiso corporation) and 2- (2-hydroxy-4- [ 1-octyloxycarbonylethoxy ] phenyl) -4,6-bis (4-phenylphenyl) -1,3,5-triazine (trade name "TINUVIN 479", manufactured by basf corporation).

Examples of the salicylate-based ultraviolet absorbers include: phenyl 2-acryloyloxy benzoate, phenyl 2-acryloyloxy-3-methylbenzoate, phenyl 2-acryloyloxy-4-methylbenzoate, phenyl 2-acryloyloxy-5-methylbenzoate, phenyl 2-acryloyloxy-3-methoxybenzoate, phenyl 2-hydroxybenzoate, phenyl 2-hydroxy-3-methylbenzoate, phenyl 2-hydroxy-4-methylbenzoate, phenyl 2-hydroxy-5-methylbenzoate, phenyl 2-hydroxy-3-methoxybenzoate, and 3,5-di-tert-butyl-4-hydroxybenzoate 2,4-di-tert-butylphenyl (trade name "TINUVIN 120", manufactured by basf corporation).

Examples of the benzophenone-based ultraviolet absorber and the hydroxybenzophenone-based ultraviolet absorber include: 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid, 2-hydroxy-4-octyloxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 4-benzyloxy-2-hydroxybenzophenone, 2,2' -dihydroxy-4-methoxybenzophenone (trade name "KEMISORB 111", manufactured by CHEMICPOLO CHEMIC CHEMICAL CO., LTD.), 2,2',4,4' -tetrahydroxybenzophenone (trade name "SEESORB 106", manufactured by SHIPLO CHEMIC CHEMICAL CO., LTD.) and 2,2' -dihydroxy-4,4 ' -dimethoxybenzophenone.

Examples of the cyanoacrylate-based ultraviolet absorber include: alkyl 2-cyanoacrylates, cycloalkyl 2-cyanoacrylates, alkoxyalkyl 2-cyanoacrylates, alkenyl 2-cyanoacrylates and alkynyl 2-cyanoacrylates.

The ultraviolet absorber contained in the pressure-sensitive adhesive layer 11 is preferably at least one selected from the group consisting of benzotriazole-based ultraviolet absorbers, hydroxyphenyl triazine-based ultraviolet absorbers, and benzophenone-based ultraviolet absorbers, from the viewpoint of having high ultraviolet absorptivity and high light stability, or from the viewpoint of easily obtaining the pressure-sensitive adhesive layer 11 having high transparency. The ultraviolet absorber contained in the pressure-sensitive adhesive layer 11 is more preferably a benzotriazole-based ultraviolet absorber in which a phenyl group having a hydrocarbon group having 6 or more carbon atoms and a hydroxyl group as substituents is bonded to a nitrogen atom constituting the benzotriazole ring.

In the case where the pressure-sensitive adhesive layer 11 contains an ultraviolet absorber, the content of the ultraviolet absorber in the pressure-sensitive adhesive layer is preferably 0.01 parts by weight or more, more preferably 0.05 parts by weight or more, and still more preferably 0.1 parts by weight or more, per 100 parts by weight of the pressure-sensitive adhesive or acrylic polymer in the pressure-sensitive adhesive layer 11, from the viewpoint of controlling the transmittance of light having a wavelength of 350nm in the pressure-sensitive adhesive layer 11 to achieve high ultraviolet absorbability. From the viewpoint of suppressing the occurrence of yellowing of the pressure-sensitive adhesive accompanying the addition of the ultraviolet absorber in the pressure-sensitive adhesive layer 11 and realizing excellent optical properties and high transparency, the content of the ultraviolet absorber in the pressure-sensitive adhesive layer 11 is preferably 10 parts by weight or less, more preferably 9 parts by weight or less, and still more preferably 8 parts by weight or less, relative to 100 parts by weight of the pressure-sensitive adhesive or the acrylic polymer in the pressure-sensitive adhesive layer 11.

The adhesive layer 11 may contain a light stabilizer. When the pressure-sensitive adhesive layer 11 contains a light stabilizer, it preferably contains an ultraviolet absorber together. The light stabilizer is a chemical substance capable of trapping radicals that can be generated by irradiation with light such as ultraviolet rays. Examples of light stabilizers include: amine light stabilizers such as phenol light stabilizers, phosphorus light stabilizers, thioether light stabilizers and hindered amine light stabilizers. The pressure-sensitive adhesive layer 11 may contain one kind of light stabilizer, or may contain two or more kinds of light stabilizers.

Examples of the phenolic light stabilizer include: 2,6-di-tert-butyl-4-methylphenol, 4-hydroxymethyl-2,6-di-tert-butylphenol, 2,6-di-tert-butyl-4-ethylphenol, butylated hydroxyanisole, N-octadecyl-3- (4-hydroxy-3,5-di-tert-butylphenyl) propionate, distearyl-4-hydroxy-3-methyl-5-tert-butyl) benzylmalonate, tocopherol, 2,2' -methylenebis (4-methyl-6-tert-butylphenol), 2,2' -methylenebis (4-ethyl-6-tert-butylphenol), 4,4' -methylenebis (2,6-di-tert-butylphenol), 4,4' -butylidenebis (6-tert-butyl-m-cresol), 4,4' -thiobis (6-tert-butyl-m-cresol), styrenated phenol, N ' -hexamethylenebis (6262-di-tert-butyl-4-methylphenol), 4-methylphenol, 4-butylated propionylamide, 4-tert-butylpropionyloxypropylpropionic acid, tert-butyl-3438, tert-butyl-methyl propionate, 3472-butyl-35 ' -butylidenebis hydrogenated 2,2' -methylenebis (4-methyl-6-cyclohexylphenol), 2,2' -methylenebis [6- (1-methylcyclohexyl) p-cresol ], 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, triethylene glycol bis [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate ], 2,2' -oxamidebis [3- (3424 zxft 34ft 3424-di-tert-butyl-4-hydroxyphenyl) propionate ], 6- (4-hydroxy-3535 zxft-butylanilino) -2,4-dioctylthio-4284-triazine, bis [ 2-tert-butyl-4-methyl-6- (2-hydroxy-6-hydroxy-3535-di-tert-butyl anilino) -3584-dioctylthio-4284-triazine, bis [ 2-tert-butyl-4-methyl-6- (2-hydroxy-3-tert-butyl-4-hydroxyphenyl) propionyl 5756, bis- [3- (3425-ethyl ] -5-tert-butyl-5-phenyl-ethyl-32575-ethyl-oxa-ethyl } -3225-methyl-5-ethyl-tert-butyl-methyl-phenyl ] -propionyl } -325756.

Examples of the phosphorus-containing light stabilizer include: tris (nonylphenyl) phosphite, tris (2,4-di-tert-butylphenyl) phosphite, tris [ 2-tert-butyl-4- (3-tert-butyl-4-hydroxy-5-methylphenylsulfanyl) -5-methylphenyl ] phosphite, tridecyl phosphite, octyl diphenyl phosphite, diphenyl didecyl phosphite, ditridecyl phosphite, distearyl pentaerythritol diphosphite, di (nonylphenyl) pentaerythritol diphosphite, pentaerythritol diphosphite bis (2,4-di-tert-butylphenyl) ester, pentaerythritol diphosphite bis (2,6-di-tert-butyl-4-methylphenyl) ester, pentaerythritol diphosphite bis (2,4,6-tri-tert-butylphenyl) ester, isopropylidene bisphenol diphosphite tetra (tridecyl) ester, 4,4' -n-butylidene bis (2-tert-butyl-5-methylphenol) diphosphite tetra (tridecyl) ester, 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butanetriphosphite hexa (tridecyl) ester, biphenylene diphosphonite tetra (2,4-di-tert-butylphenyl) ester, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide and tris (2- [ (2,4,8,10-dibenzo [ d, f 1,3,2] phosphaphenanthreo-yl) ethyl) 6-ethyl ester.

Examples of the thioether-based light stabilizer include: dialkyl thiodipropionate compounds such as dilauryl thiodipropionate, dimyristyl thiodipropionate and distearyl thiodipropionate, and β -alkylmercaptopropionate compounds of polyhydric alcohols such as tetrakis [ methylene (3-dodecylthio) propionate ] methane.

Examples of the amine-based light stabilizer include: a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol (trade name "TINUVIN 622", manufactured by BASF corporation), a reaction product of this polymer with N, N ', N ", N'" -tetrakis (4,6-bis (butyl- (N-methyl-2,2,6,6-tetramethylpiperidin-4-yl) amino) triazin-2-yl) -4,7-diazecane-1,10-diamine 3754 (trade name "TINUVIN 119", manufactured by BASF corporation), poly [ {6- (1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl } { (2,2,6,6-tetramethyl-4-piperidinyl) imino } hexamethylene { (3424 zxft-tetramethyl-4-piperidinyl) imino } { (trade name "TIxft-3584-ethyl-3523", manufactured by BASF corporation), a reaction product of bis [ methyl-ethyl-3523 "(trade name" TInxVIN-3584 ", manufactured by BASF-3523", a reaction product of bis- (NUVIN-3523 ", a reaction product of bis- (Nz) malonic acid) (trade name" TIxft-4235 ", a reaction product" bis- (Nz-3584 ", manufactured by BASF-3523", a reaction product of bis [ 31-3584 ", a reaction product of bis- (3432-bis- (Nz) bis- (3-zxft-3584"),123 ", (manufactured by BASF), basf corporation), a reaction product of cyclohexane and peroxide N-butyl-2,2,6,6-tetramethyl-4-piperidinamine-2,4,6-trichloro-1,3,5-triazine with 2-aminoethanol (trade name "TINUVIN 152", manufactured by basf corporation), a mixture of bis (1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate with methyl sebacate 1,2,2,6,6-pentamethyl-4-piperidinyl ester (trade name "TINUVIN 292", manufactured by basf corporation), and a mixed ester of 1,2,3,4-butanetetracarboxylic acid with 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro [5.5] undecane (trade name "ADK STAP 5363", manufactured by staxft 5329). As the amine stabilizer, a hindered amine stabilizer is particularly preferable.

In the case where the pressure-sensitive adhesive layer 11 contains a light stabilizer, the content of the light stabilizer in the pressure-sensitive adhesive layer 11 is preferably 0.1 part by weight or more, and more preferably 0.2 part by weight or more, per 100 parts by weight of the pressure-sensitive adhesive or the acrylic polymer in the pressure-sensitive adhesive layer 11, from the viewpoint of achieving sufficient light resistance in the pressure-sensitive adhesive layer 11. From the viewpoint of suppressing coloring due to a light stabilizer in the pressure-sensitive adhesive layer 11 and achieving high transparency, the content of the light stabilizer in the pressure-sensitive adhesive layer 11 is preferably 5 parts by weight or less, and more preferably 3 parts by weight or less, per 100 parts by weight of the pressure-sensitive adhesive or the acrylic polymer in the pressure-sensitive adhesive layer 11.

The pressure-sensitive adhesive or the acrylic polymer contained in the pressure-sensitive adhesive layer 11 may be crosslinked with a crosslinking agent other than the above-mentioned copolymerizable crosslinking agent. The gel fraction of the pressure-sensitive adhesive layer 11 can be adjusted by crosslinking the pressure-sensitive adhesive or the acrylic polymer with the crosslinking agent. Examples of such a crosslinking agent include: isocyanate crosslinking agent, epoxy crosslinking agent, melamine crosslinking agent, peroxide crosslinking agent, urea crosslinking agent, and urethane crosslinking agent a metal alkoxide crosslinking agent, a metal chelate crosslinking agent, a metal salt crosslinking agent, a carbodiimide crosslinking agent,

Oxazoline crosslinking agents, aziridine crosslinking agents and amine crosslinking agents. The pressure-sensitive adhesive layer 11 may contain one kind of the crosslinking agent, or may contain two or more kinds of the crosslinking agents. In the present embodiment, at least one selected from the group consisting of isocyanate-based crosslinking agents and epoxy-based crosslinking agents is preferably used.

Examples of the isocyanate-based crosslinking agent include: lower aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates. Examples of the lower aliphatic polyisocyanate include: 1,2-ethylene diisocyanate, 1,4-butylene diisocyanate, and 1,6-hexamethylene diisocyanate. Examples of the alicyclic polyisocyanate include: cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate, hydrogenated toluene diisocyanate, and hydrogenated xylene diisocyanate. Examples of the aromatic polyisocyanate include: 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 4,4' -diphenylmethane diisocyanate, and xylylene diisocyanate. Further, as the isocyanate-based crosslinking agent, there can be mentioned: commercially available products such as a trimethylolpropane/tolylene diisocyanate adduct (trade name "Coronate L", manufactured by Nippon polyurethane industries Co., ltd.), a trimethylolpropane/hexamethylene diisocyanate adduct (trade name "Coronate HL", manufactured by Nippon polyurethane industries Co., ltd.), and a trimethylolpropane/xylylene diisocyanate adduct (trade name "Takenate D-110N", manufactured by Mitsui chemical Co., ltd.).

Examples of the epoxy-based crosslinking agent (polyfunctional epoxide) include: n, N, N ', N' -tetraglycidyl m-xylylenediamine, diglycidylaniline, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, tris (2-hydroxyethyl) isocyanurate triglycidyl ether, resorcinol diglycidyl ether, and bisphenol S diglycidyl ether. Further, as the epoxy crosslinking agent, an epoxy resin having two or more epoxy groups can be cited. In addition, as the epoxy crosslinking agent, a commercially available product such as "TETRAD C" (manufactured by mitsubishi gas chemical corporation) may be mentioned.

In the case where the pressure-sensitive adhesive layer 11 contains the crosslinking agent for crosslinking between acrylic polymers as described above, the content of the crosslinking agent in the pressure-sensitive adhesive layer 11 is preferably 0.001 parts by weight or more, more preferably 0.01 parts by weight or more, relative to 100 parts by weight of the pressure-sensitive adhesive or acrylic polymer in the pressure-sensitive adhesive layer 11, from the viewpoint of achieving sufficient adhesion reliability to an adherend in the pressure-sensitive adhesive layer 11. From the viewpoint of exhibiting appropriate flexibility in the pressure-sensitive adhesive layer 11 and achieving good adhesion, the content of the crosslinking agent in the pressure-sensitive adhesive layer 11 is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, per 100 parts by weight of the pressure-sensitive adhesive or the acrylic polymer in the pressure-sensitive adhesive layer 11.

The pressure-sensitive adhesive layer 11 may further contain additives such as a crosslinking accelerator, a tackifier resin, an antioxidant, a filler, a colorant such as a pigment or a dye, an antioxidant, a chain transfer agent, a plasticizer, a softener, a surfactant, and an antistatic agent, as required. Examples of the tackifier resin include: rosin derivatives, polyterpene resins (ポリテルペン colophony), petroleum resins and oil-soluble phenol resins.

The thickness of the pressure-sensitive adhesive sheet body 10 or the pressure-sensitive adhesive layer 11 is preferably 5 μm or more, more preferably 10 μm or more, more preferably 25 μm or more, more preferably 50 μm or more, more preferably 100 μm or more, and more preferably 200 μm or more. The thickness of the pressure-sensitive adhesive sheet main body 10 or the pressure-sensitive adhesive layer 11 is preferably 1000 μm or less, more preferably 900 μm or less, and still more preferably 800 μm or less.

The haze in the thickness direction of the optical adhesive sheet main body 10 or the adhesive layer 11 is preferably 3% or less, more preferably 2.5% or less, more preferably 2% or less, more preferably 1.5% or less, and more preferably 1% or less. The haze is a value measured according to JIS K7136. The total light transmittance in the visible light wavelength range of the optical pressure-sensitive adhesive sheet body 10 or the pressure-sensitive adhesive layer 11 is, for example, 85% or more. The total light transmittance is a value measured according to JIS K7361-1.

Storage modulus at 23 ℃ of pressure-sensitive adhesive layer 11, i.e., of pressure-sensitive adhesive layer 11The storage modulus at 23 ℃ of the constituent material is preferably 1.0X 10 ⁴ Pa or more, more preferably 5.0X 10 ⁴ Pa or more, more preferably 1.0X 10 ⁵ Pa or above. The upper limit of the storage modulus at 23 ℃ of the pressure-sensitive adhesive layer 11 is, for example, 1.0X 10 ⁷ Pa. The storage modulus can be determined by, for example, dynamic viscoelasticity measurement using a dynamic viscoelasticity measurement apparatus (trade name "ARES", manufactured by Rheometric). In this measurement, the measurement mode is set to the shear mode, the measurement temperature range is set to, for example, -70 ℃ to 150 ℃, the temperature increase rate is set to, for example, 5 ℃/min, and the frequency is set to, for example, 1Hz.

The release liner L1 in the pressure-sensitive adhesive sheet X1 is a member for covering one pressure-sensitive adhesive surface 11' of the pressure-sensitive adhesive sheet main body 10, and is peeled from the pressure-sensitive adhesive sheet main body 10 when the pressure-sensitive adhesive sheet main body 10 is bonded to an adherend. The release liner L2 in the pressure-sensitive adhesive sheet X1 is a member for covering the other pressure-sensitive adhesive surface 11' of the pressure-sensitive adhesive sheet main body 10, and is peeled from the pressure-sensitive adhesive sheet main body 10 when the pressure-sensitive adhesive sheet main body 10 is bonded to an adherend. Examples of the release liners L1 and L2 include a release liner having a release treatment layer on the surface of a liner base material such as a resin film or paper, and a release liner containing a low-tackiness material such as a fluoropolymer or a polyolefin resin. As the resin film for a release liner, for example, polyethylene terephthalate can be cited. The release-treated layer is a surface-treated layer formed on the surface of the backing substrate by allowing a silicone-based release treatment agent, a long-chain alkyl-based release treatment agent, a fluorine-containing release treatment agent, or a molybdenum sulfide release treatment agent to act on the surface of the backing substrate, for example. Examples of the fluoropolymer for the release liner include polytetrafluoroethylene. Examples of the polyolefin-based resin for the release liner include polyethylene and polypropylene. The release liners L1, L2 each have a thickness of, for example, 5 μm to 200. Mu.m.

A part or the whole of the region of the outer peripheral end 11a of the pressure-sensitive adhesive layer 11 as the pressure-sensitive adhesive sheet main body 10 in the pressure-sensitive adhesive sheet X1 is located at a position spaced from the outer peripheral ends L1a, L2a of the release liners L1, L2 in the pressure-sensitive adhesive sheet in-plane direction, for example, as shown in fig. 2. The pressure-sensitive adhesive sheet in-plane direction means an in-plane direction orthogonal to the thickness direction of the pressure-sensitive adhesive sheet X1 or the pressure-sensitive adhesive sheet main body 10 (pressure-sensitive adhesive layer 11). The outer peripheral ends L1a, L2a of the release liners L1, L2 may be at the same position or different positions in the in-plane direction of the pressure-sensitive adhesive sheet. The outer peripheral ends L1a, L2a of the release liners L1, L2 shown in fig. 2 are at the same position in the adhesive sheet in-plane direction. In the present embodiment, specifically, a part or all of the outer peripheral edge 11a of the pressure-sensitive adhesive layer 11 is located at a position 5 to 2000 μm from the closest outer peripheral edge L1a of the release liner L1 to the inside of the pressure-sensitive adhesive sheet with respect to the closest outer peripheral edge L1a of the release liner L1 and at a position 5 to 2000 μm from the closest outer peripheral edge L2a of the release liner L2 to the inside of the pressure-sensitive adhesive sheet with respect to the closest outer peripheral edge L1a of the release liner L1 in the pressure-sensitive adhesive sheet in the in-plane direction. The distance D in the in-plane direction of the pressure-sensitive adhesive sheet between the outer peripheral end 11a of the pressure-sensitive adhesive layer 11 and the outer peripheral end L1a of the release liner L1 at a position spaced apart from the outer peripheral end L1a in the in-plane direction of the pressure-sensitive adhesive sheet is preferably 10 μm or more, more preferably 30 μm or more, more preferably 40 μm or more, and more preferably 50 μm or more. The distance D between the outer peripheral ends 11a and L1a is preferably 1500 μm or less, more preferably 1000 μm or less, more preferably 500 μm or less, and more preferably 300 μm or less. The distance D in the in-plane direction of the pressure-sensitive adhesive sheet between the outer peripheral end 11a of the pressure-sensitive adhesive layer 11 and the outer peripheral end L2a of the release liner L2 at a position spaced apart from the outer peripheral end L2a in the in-plane direction of the pressure-sensitive adhesive sheet is preferably 10 μm or more, more preferably 30 μm or more, more preferably 40 μm or more, and more preferably 50 μm or more. The distance D between the outer peripheral ends 11a and L2a is preferably 1500 μm or less, more preferably 1000 μm or less, more preferably 500 μm or less, and more preferably 300 μm or less.

The psa sheet X1 having the above-described structure can be produced, for example, as follows. First, a release-liner-attached double-sided psa sheet raw material is prepared for forming the psa sheet X1 by punching, cutting, or other processing. For example, a release-liner-equipped double-sided adhesive sheet material can be produced by applying an adhesive composition for forming the adhesive layer 11 to a predetermined release liner to form an adhesive composition layer, further laminating release liners on the adhesive composition layer, and curing the adhesive composition between the release liners. The release-liner-attached double-sided adhesive sheet stock material has a laminated structure including a preliminary first release liner for forming a release liner L1, a preliminary second release liner for forming a release liner L2, and a preliminary double-sided adhesive sheet main body (adhesive layer) between the preliminary first release liner and the preliminary second release liner. Next, the double-sided psa sheet stock with the release liner is processed while being subjected to a pressure in the thickness direction thereof, thereby forming a psa sheet X1 having a desired overall dimension. The double-sided adhesive sheet material with a release liner is elastically deformable in response to a pressure applied in a thickness direction, and elastically stretches in an in-plane direction of the material at an elongation rate corresponding to the pressure applied, and is elastically expanded from between the first release liner and the second release liner at an outer peripheral end of the material. Examples of the processing means include blanking and/or cutting. As the punching process, for example, a so-called Thompson (Thompson) process, that is, a punching process by a Thompson blade may be mentioned. As the cutting process, for example, a so-called milling (full back) process is cited. In this processing step, specifically, the double-sided adhesive sheet raw material with the release liner in a state of being pressurized in the thickness direction is subjected to processing such as punching and/or cutting so that a part or the whole of the outer peripheral edge of the double-sided adhesive sheet X1 is formed into a new shape by processing to obtain the double-sided adhesive sheet X1 having a target outer dimension. Then, in the pressure-sensitive adhesive sheet X1 obtained by releasing the pressure-sensitive adhesive state, the pressure-sensitive adhesive layer 11 is restored from the elastically deformed state to the non-deformed state, and the outer peripheral edge of the pressure-sensitive adhesive sheet X1 newly generated in the processing step is set back inward between the release liner L1 and the release liner L2. That is, in the produced psa sheet X1, as shown in fig. 2, for example, a part or all of the outer peripheral edge 11a of the psa layer 11 is located inward in the psa sheet plane direction at a position spaced from the outer peripheral edges L1a, L2a of the release liners L1, L2.

As the adhesive composition for forming the adhesive layer 11, for example, an adhesive composition which can be cured by irradiation with active energy rays to cause a polymerization reaction is used. That is, the pressure-sensitive adhesive layer 11 is, for example, a cured product of an active energy ray-curable pressure-sensitive adhesive composition. The active energy ray-curable pressure-sensitive adhesive composition for forming an acrylic pressure-sensitive adhesive layer contains at least a monomer for forming an acrylic polymer, an oligomer, and a photopolymerization initiator. The monomers and oligomers in the composition can be provided in the form of so-called partial polymers of a monomer mixture of a specified composition for forming the acrylic polymer. The pressure-sensitive adhesive composition may contain other components as needed as components of the pressure-sensitive adhesive layer 11 to be formed. The active energy ray to be irradiated to the active energy ray-curable adhesive composition for curing the adhesive layer 11 includes, for example: ultraviolet rays, alpha rays, beta rays, gamma rays, neutron rays and electron rays, and preferably ultraviolet rays are used. The active energy ray-curable pressure-sensitive adhesive composition for forming an acrylic pressure-sensitive adhesive layer, which is irradiated with an active energy ray, is activated by a photopolymerization initiator to cause an initiation reaction, and the polymerization reaction proceeds toward the formation of an acrylic polymer. When the curable adhesive composition for forming the adhesive layer is cured by irradiation with active energy rays such as ultraviolet rays, the adhesive layer after being appropriately cured can be easily obtained even when the coating film of the adhesive composition is thick. Therefore, a configuration in which the pressure-sensitive adhesive layer 11 is a cured product of an active energy ray-curable pressure-sensitive adhesive composition is suitable for realizing a sufficiently cured pressure-sensitive adhesive layer 11 even though it is thick.

Examples of the photopolymerization initiator include: benzoin ether type photopolymerization initiator, acetophenone type photopolymerization initiator, α -ketol type photopolymerization initiator, aromatic sulfonyl chloride type photopolymerization initiator, photoactive oxime type photopolymerization initiator, benzoin type photopolymerization initiator, biphenyl acyl type photopolymerization initiator, benzophenone type photopolymerization initiator, ketal type photopolymerization initiator, and thioxanthone type photopolymerization initiator. Examples of the benzoin ether-based photopolymerization initiator include: benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, and 2,2-dimethoxy-1,2-diphenylethan-1-one. Examples of the acetophenone-based photopolymerization initiator include: 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexylphenylketone, 4-phenoxydichloroacetophenone and 4-tert-butyldichloroacetophenone. Examples of the α -ketol photopolymerization initiator include: 2-methyl-2-hydroxypropiophenone and 1- [4- (2-hydroxyethyl) phenyl ] -2-methylpropan-1-one. Examples of the aromatic sulfonyl chloride-based photopolymerization initiator include 2-naphthalenesulfonyl chloride. As the optically active oxime type photopolymerization initiator, for example, 1-phenyl-1,2-propanedione-2- (O-ethoxycarbonyl) oxime may be mentioned. Examples of the benzoin photopolymerization initiator include benzoin. Examples of the biphenylacyl photopolymerization initiator include biphenylacyl. Examples of the benzophenone-based photopolymerization initiator include: benzophenone, benzoylbenzoic acid, 3,3' -dimethyl-4-methoxybenzophenone and polyvinylbenzophenone. Examples of the ketal photopolymerization initiator include: benzil dimethyl ketal. Examples of the thioxanthone photopolymerization initiator include: thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone. The content of the photopolymerization initiator in the active energy ray-curable adhesive composition is, for example, 0.01 to 3% by weight.

As the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 11, for example, a solvent-based pressure-sensitive adhesive composition or an emulsion-based pressure-sensitive adhesive composition which contains an acrylic polymer as a pressure-sensitive adhesive and is curable by heat drying can be used. The composition may contain other components as needed as components of the adhesive layer 11 to be formed. The acrylic polymer in the pressure-sensitive adhesive composition can be obtained by polymerizing a raw material monomer component for forming the acrylic polymer. Examples of the polymerization method include: solution polymerization, emulsion polymerization, and bulk polymerization. In the case of solution polymerization, aromatic hydrocarbons, aliphatic hydrocarbons, alicyclic hydrocarbons, esters and ketones can be used as the solvent. Examples of the aromatic hydrocarbon solvent include toluene and benzene. Examples of the aliphatic hydrocarbon solvent include n-hexane and n-heptane. Examples of the alicyclic hydrocarbon solvent include cyclohexane and methylcyclohexane. Examples of the ester solvent include ethyl acetate and n-butyl acetate. Examples of ketone solvents include: methyl ethyl ketone and methyl isobutyl ketone. In the solution polymerization, one solvent may be used, or two or more solvents may be used.

When the raw material monomer component is polymerized to obtain an acrylic polymer, a polymerization initiator may be used. Depending on the kind of polymerization reaction, for example, a photopolymerization initiator or a thermal polymerization initiator can be used. In the polymerization, one polymerization initiator may be used, or two or more polymerization initiators may be used.

Examples of the photopolymerization initiator include: the above benzoin ether-based photopolymerization initiator, acetophenone-based photopolymerization initiator, α -ketol-based photopolymerization initiator, aromatic sulfonyl chloride-based photopolymerization initiator, photoactive oxime-based photopolymerization initiator, benzoin-based photopolymerization initiator, biphenyl acyl-based photopolymerization initiator, benzophenone-based photopolymerization initiator, ketal-based photopolymerization initiator, and thioxanthone-based photopolymerization initiator. The amount of the photopolymerization initiator used is, for example, 0.01 to 3 parts by weight based on the total amount (100 parts by weight) of the monomer components.

Examples of the thermal polymerization initiator include: an azo polymerization initiator, a peroxide polymerization initiator, and a redox polymerization initiator. As the azo polymerization initiator, for example: 2,2 '-azobisisobutyronitrile, 2,2' -azobis (2-methylbutyronitrile), 2,2 '-azobis (2-methylpropionic acid) dimethyl ester and 4,4' -azobis (4-cyanovaleric acid). Examples of the peroxide-based polymerization initiator include: benzoyl peroxide and tert-butyl peroxymaleate. The amount of the thermal polymerization initiator used is, for example, 0.05 to 0.3 parts by weight based on the total amount (100 parts by weight) of the monomer components.

In the polymerization for obtaining the acrylic polymer, a chain transfer agent may be used in order to adjust the molecular weight of the acrylic polymer. Examples of chain transfer agents include: alpha-thioglycerol, 2-mercaptoethanol, 2,3-dimercapto-1-propanol, octyl mercaptan, tert-nonyl mercaptan, dodecyl mercaptan (lauryl mercaptan), tert-dodecyl mercaptan, glycidyl mercaptan, thioglycolic acid, methyl thioglycolate, ethyl thioglycolate, propyl thioglycolate, butyl thioglycolate, tert-butyl thioglycolate, 2-ethylhexyl thioglycolate, octyl thioglycolate, isooctyl thioglycolate, decyl thioglycolate and dodecyl thioglycolate. As the chain transfer agent, one kind of chain transfer agent may be used, or two or more kinds of chain transfer agents may be used. In the present embodiment, as the chain transfer agent, α -thioglycerol is preferably used. The amount of the chain transfer agent used is, for example, 0.01 to 0.5 parts by weight based on the total amount (100 parts by weight) of the monomer components for obtaining the acrylic polymer.

When the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 11, such as an active energy ray-curable pressure-sensitive adhesive composition, a solvent-based pressure-sensitive adhesive composition, or an emulsion-based pressure-sensitive adhesive composition, contains the acrylic oligomer, the oligomer can be obtained by polymerizing a raw material monomer component having a predetermined composition. Examples of the polymerization method include: solution polymerization, emulsion polymerization, and bulk polymerization. As the solvent used for the solution polymerization, the solvents described above as solvents that can be used in the solution polymerization for obtaining the acrylic polymer can be cited. In the solution polymerization, one kind of solvent may be used, or two or more kinds of solvents may be used. In addition, when the raw material monomer components are polymerized to obtain the oligomer, a polymerization initiator may be used. The polymerization initiator may be the above photopolymerization initiator or thermal polymerization initiator, which is a polymerization initiator used in polymerization for obtaining an acrylic polymer. In the polymerization, one polymerization initiator may be used, or two or more polymerization initiators may be used.

A part or all of the region of the outer peripheral end 11a of the adhesive sheet main body 10 or the adhesive layer 11 in the adhesive sheet X1 as a release-liner-attached double-sided adhesive sheet manufactured as described above, for example, is located at a position spaced from the outer peripheral ends L1a, L2a of the release liners L1, L2 in the in-plane direction of the adhesive sheet as shown in fig. 2, for example. The outer peripheral end 11a of the pressure-sensitive adhesive layer 11 has a region located at a position spaced from the outer peripheral ends L1a, L2a of the release liners L1, L2 in the pressure-sensitive adhesive sheet in-plane direction, so that, for example, a concave shape is formed at the outer peripheral end of the pressure-sensitive adhesive sheet X1 in a cross section in the thickness direction of the sheet. The distance D in the adhesive sheet in-plane direction between the outer peripheral end 11a of the adhesive layer 11 located at a position spaced apart from the outer peripheral ends L1a, L2a of the release liners L1, L2 in the adhesive sheet in-plane direction and the outer peripheral ends L1a, L2a is 5 μm to 2000 μm as described above. When the release liner L1 or the release liner L2 is peeled from the psa sheet X1, the peeling operation is facilitated if the psa sheet body 10 or the outer peripheral edge 11a of the psa layer 11 is located at a position (outer peripheral edge separation point) spaced from the outer peripheral edges L1a, L2a of the release liners L1, L2 in the inner direction of the psa sheet. Specifically, in the peripheral end spaced portion, for example, the fingertip of the worker is likely to contact the release liner L1 or the release liner L2 to be peeled without contacting the adhesive layer 11, and therefore, appropriate deformation for peeling is likely to start on the release liner, and separation of the release liner and the adhesive layer 11 from the end of the interface therebetween is likely to start. In this way, the release liners L1 and L2 of the pressure-sensitive adhesive sheet X1 can be easily peeled from the pressure-sensitive adhesive sheet body 10 by, for example, manual work.

In addition, when the release liner L1 or the release liner L2 is peeled off from the outer peripheral edge separation portion of the adhesive sheet X1 as described above, it is easy for the fingertip of the worker to contact the release liner L1 or the release liner L2 to be peeled without contacting the adhesive layer 11. At the same time, at the peripheral edge interval portion of the adhesive sheet X1, as described above, it is easy to initiate appropriate deformation for peeling on the release liner and to initiate separation of the release liner L1 or the release liner L2 to be peeled from the end portion of the interface between the adhesive layer 11 and the release liner L1. These features are suitable for the psa sheet X1 that can be peeled off with the release liner at the peripheral edge separation portion, in order to prevent the adhesive surface 11' or the psa layer 11 from being partially damaged or chipped by the release liner pulling away a part of the psa sheet body 10 or the psa layer 11 during the peeling off of the release liner.

In addition, in the psa sheet X1, the distance D in the in-plane direction of the psa sheet between the outer peripheral end 11a of the psa layer 11 located at a position spaced apart from the outer peripheral ends L1a, L2a of the release liners L1, L2 in the in-plane direction of the psa sheet and the outer peripheral ends L1a, L2a is 5 μm to 2000 μm as described above. The psa sheet X1 having such a configuration is suitable for efficient production by elastic deformation of the psa layer and subsequent shape recovery, as described above. The distance (separation distance D) of the separation between the outer peripheral ends L1a, L2a of the release liners L1, L2 and the outer peripheral end 11a of the adhesive layer 11, which is generated as a result of utilizing the elastic deformation and the shape recovery thereafter of the adhesive layer, tends to be in the shorter range of 5 μm to 2000 μm. On the other hand, in order to manufacture a double-sided psa sheet with a release liner having an outer dimension greater than 5000 μm or more than the psa sheet body 10 or the psa layer 11, for example, after manufacturing a double-sided psa sheet with a release liner having an outer dimension the same as that of the psa sheet body 10 or the psa layer 11 on the psa surfaces 11', it is necessary to replace each release liner ( り instead of える) with a release liner having an outer dimension greater than that of the psa sheet body 10 by the above-described range. However, such a method is not efficient from the viewpoint of material cost and the number of steps. The psa sheet X1 having the separation distance D between the outer peripheral end 11a of the psa layer 11 and the outer peripheral ends L1a, L2a of the release liners L1, L2 at a position spaced apart from the outer peripheral ends L1a, L2a in the in-plane direction of the psa sheet, of 5 μm to 2000 μm is suitable for efficient production through the above-described process utilizing elastic deformation of the psa layer and subsequent shape recovery.

As described above, the pressure-sensitive adhesive sheet X1 which is a double-sided pressure-sensitive adhesive sheet with a release liner is suitable for facilitating the operation of peeling the release liners L1 and L2, suppressing local breakage or chipping of the pressure-sensitive adhesive layer 11 at the time of peeling the release liner, and for efficient production. In addition, the pressure-sensitive adhesive sheet X1 in which the separation distance D between the outer peripheral end 11a of the pressure-sensitive adhesive layer 11 and the outer peripheral ends L1a, L2a of the release liners L1, L2 at a position spaced apart from the outer peripheral ends L1a, L2a in the in-plane direction of the pressure-sensitive adhesive sheet is 5 μm to 2000 μm is suitable for achieving the size required for the pressure-sensitive adhesive sheet body 10 while avoiding the outer dimensions of the pressure-sensitive adhesive sheet X1, i.e., the outer dimensions of the release liners L1, L2 from greatly exceeding the size of the pressure-sensitive adhesive sheet body 10 and becoming excessively large.

As described above, the thickness of the pressure-sensitive adhesive sheet body 10 or the pressure-sensitive adhesive layer 11 in the pressure-sensitive adhesive sheet X1 is preferably 5 μm or more, more preferably 10 μm or more, more preferably 25 μm or more, more preferably 50 μm or more, more preferably 100 μm or more, and more preferably 200 μm or more. Such a configuration is suitable in terms of achieving sufficient adhesive force of the pressure-sensitive adhesive layer 11 to the adherend. The pressure-sensitive adhesive layer 11 having a thickness of 25 μm or more, preferably 50 μm or more, more preferably 100 μm or more, and more preferably 200 μm or more is preferably configured to ensure that the separation distance D between the outer peripheral ends L1a and L2a of the release liners L1 and L2 and the outer peripheral end 11a of the pressure-sensitive adhesive layer 11 is 5 μm or more and longer at the outer peripheral end separation portion. This is because: the thicker the adhesive layer is, the more the amount of elastic deformation of the adhesive layer in the in-plane direction when the adhesive layer is subjected to a pressing force in the thickness direction tends to increase. On the other hand, from the viewpoint of ease of formation of the pressure-sensitive adhesive layer 11, the thickness of the pressure-sensitive adhesive sheet main body 10 or the pressure-sensitive adhesive layer 11 is preferably 1000 μm or less, more preferably 900 μm or less, and still more preferably 800 μm or less, as described above.

The storage modulus at 23 ℃ of the adhesive layer 11 is preferably 1.0X 10 as described above ⁴ Pa or more, more preferably 5.0X 10 ⁴ Pa or more, more preferably 1.0X 10 ⁵ Pa or above. In this configuration, the distance D between the outer peripheral edge and the peripheral edge is 5 μmThe pressure-sensitive adhesive sheet X1 having a thickness of about 2000 μm is preferably efficiently produced by elastic deformation of the pressure-sensitive adhesive layer and subsequent shape recovery.

Fig. 3 is a partial sectional view of an adhesive sheet X2 as a double-sided adhesive sheet with a release liner according to an embodiment of the present invention. The adhesive sheet X2 has a laminated structure including an adhesive sheet main body 20 as a double-sided adhesive sheet main body and release liners L1 and L2. The psa sheet body 20 is positioned between the release liners L1 and L2, has a laminated structure including a psa layer 21 as a first psa layer, a psa layer 22 as a second psa layer, and a substrate 23 positioned between the psa layers 21 and 22, and is light-transmissive in the present embodiment. The pressure-sensitive adhesive layer 21 in the pressure-sensitive adhesive sheet main body 20 has a pressure-sensitive adhesive surface 21 'capable of being stuck to an adherend, and the pressure-sensitive adhesive layer 22 has a pressure-sensitive adhesive surface 22' capable of being stuck to an adherend. Such a pressure-sensitive adhesive sheet main body 20 is, for example, an optical double-sided pressure-sensitive adhesive sheet that can be used for manufacturing a flat panel display or the like. A display device such as a liquid crystal display or an input device such as a touch panel has a laminated structure portion including various substrates or film bodies, and an adhesive sheet main body 20 can be used as an optical double-sided adhesive sheet for bonding predetermined members adjacent to each other in the laminated structure or as an optical double-sided adhesive sheet for filling a gap between adjacent members. The pressure-sensitive adhesive sheet X2 is a release-liner-equipped double-sided pressure-sensitive adhesive sheet with release liners L1 and L2 for covering the pressure-sensitive adhesive surfaces 21',22' of the pressure-sensitive adhesive sheet main body 20.

The adhesive layers 21 and 22 in the adhesive sheet main body 20 each contain an adhesive as a main agent. The binder and other constituent materials in the binder layers 21, 22 are the same as those described above with respect to the binder and other constituent materials in the binder layer 11. The adhesive layer 21 and the adhesive layer 22 may be formed of adhesive compositions having the same composition or may be formed of adhesive compositions having different compositions.

The thicknesses of the pressure-sensitive adhesive layers 21 and 22 are each preferably 5 μm or more, more preferably 10 μm or more, more preferably 25 μm or more, more preferably 50 μm or more, more preferably 100 μm or more, and more preferably 200 μm or more. The thicknesses of the pressure-sensitive adhesive layers 21 and 22 are each preferably 1000 μm or less, more preferably 900 μm or less, and still more preferably 800 μm or less.

The haze of the optical adhesive sheet body 20 in the thickness direction is preferably 3% or less, more preferably 2.5% or less, more preferably 2% or less, more preferably 1.5% or less, and more preferably 1% or less. The haze is a value measured according to JIS K7136. In addition, the total light transmittance in the visible light wavelength range of the optical adhesive sheet body 20 is, for example, 85% or more. The total light transmittance is a value measured according to JIS K7361-1.

The storage modulus at 23 ℃ of each of the

adhesive layers

21, 22 is preferably 1.0X 10 ⁴ Pa or more, more preferably 5.0X 10 ⁴ Pa or more, more preferably 1.0X 10 ⁵ Pa or above. The upper limit of the storage modulus at 23 ℃ of the pressure-sensitive adhesive layers 21 and 22 is, for example, 1.0X 10 ⁷ Pa. Such a storage modulus can be obtained by, for example, dynamic viscoelasticity measurement using a dynamic viscoelasticity measurement apparatus (trade name "ARES", manufactured by Rheometrics corporation) as described above.

The substrate 23 of the pressure-sensitive adhesive sheet main body 20 is a portion functioning as a support in the pressure-sensitive adhesive sheet main body 20. As materials for forming the substrate 23, for example, there can be mentioned: polyesters such as polyethylene terephthalate (PET), polyolefins such as polypropylene and polyethylene, polycarbonates, polyamides, polyimides, acrylic resins, polystyrenes, acetate fibers, polyethersulfones, and triacetyl cellulose. The substrate 23 may include one material or two or more materials. The substrate 23 may have a multilayer structure. In addition, the surface of the substrate 23 on the side of the adhesive layer 21 and the surface on the side of the adhesive layer 22 may each be subjected to a surface treatment for improving the adhesion with the adhesive layer. Examples of such surface treatment include physical treatment such as corona treatment and plasma treatment, and chemical treatment such as undercoating treatment. The thickness of the substrate 23 is 15 to 150. Mu.m, preferably 25 to 125. Mu.m, and more preferably 38 to 100. Mu.m.

The release liner L1 of the psa sheet X2 is an element for covering the adhesive surface 21' of the psa sheet main body 20 and is peeled from the psa sheet main body 20 when the psa sheet main body 20 is bonded to an adherend. The release liner L2 of the psa sheet X2 is a member for covering the adhesive surface 22' of the psa sheet main body 20 and is released from the psa sheet main body 20 when the psa sheet main body 20 is attached to an adherend. The composition and thickness of the release liners L1, L2 of the adhesive sheet X2 are as described above with respect to the composition and thickness of the release liners L1, L2 of the adhesive sheet X1.

In the adhesive sheet X2, a part or all of the area of the outer peripheral end 21a of the adhesive layer 21 of the adhesive sheet main body 20 is located at a position spaced from the outer peripheral ends L1a, L2a of the release liners L1, L2 in the adhesive sheet in-plane direction, for example, as shown in fig. 4. The pressure-sensitive adhesive sheet in-plane direction means an in-plane direction orthogonal to the thickness direction of the pressure-sensitive adhesive sheet X2 or the pressure-sensitive adhesive sheet main body 20. The outer peripheral ends L1a, L2a of the release liners L1, L2 may be at the same position or different positions in the in-plane direction of the pressure-sensitive adhesive sheet. The outer peripheral ends L1a, L2a of the release liners L1, L2 shown in fig. 4 are at the same position in the adhesive sheet in-plane direction. In the present embodiment, specifically, a part or all of the outer peripheral end 21a of the pressure-sensitive adhesive layer 21 is located at a position 5 μm to 2000 μm from the nearest outer peripheral end L1a of the release liner L1 to the inside of the pressure-sensitive adhesive sheet with respect to the nearest outer peripheral end L1a of the release liner L1 and at a position 5 μm to 2000 μm from the nearest outer peripheral end L2a of the release liner L2 to the inside of the pressure-sensitive adhesive sheet with respect to the nearest outer peripheral end L2a of the release liner L2 in the in-plane pressure-sensitive adhesive sheet direction. The separation distance D1 in the in-plane direction of the pressure-sensitive adhesive sheet between the outer peripheral end 21a of the pressure-sensitive adhesive layer 21 and the outer peripheral end L1a of the release liner L1 at a position spaced apart from the outer peripheral end L1a in the in-plane direction of the pressure-sensitive adhesive sheet is preferably 10 μm or more, more preferably 30 μm or more, more preferably 40 μm or more, and more preferably 50 μm or more. The distance D1 between the outer peripheral ends 21a and L1a is preferably 1500 μm or less, more preferably 1000 μm or less, more preferably 500 μm or less, and more preferably 300 μm or less. The separation distance D1 in the in-plane direction of the pressure-sensitive adhesive sheet between the outer peripheral end 21a of the pressure-sensitive adhesive layer 21 and the outer peripheral end L2a of the release liner L2 at a position spaced apart from the outer peripheral end L2a in the in-plane direction of the pressure-sensitive adhesive sheet is preferably 10 μm or more, more preferably 30 μm or more, more preferably 40 μm or more, and more preferably 50 μm or more. The distance D1 between the outer peripheral ends 21a and L2a is preferably 1500 μm or less, more preferably 1000 μm or less, more preferably 500 μm or less, and more preferably 300 μm or less. On the other hand, the separation distance D2 in the in-plane direction of the pressure-sensitive adhesive sheet between the outer peripheral end 22a of the pressure-sensitive adhesive layer 22 and the outer peripheral end L2a of the release liner L2 at a position spaced apart from the outer peripheral end L2a in the in-plane direction of the pressure-sensitive adhesive sheet is preferably 10 μm or more, more preferably 30 μm or more, more preferably 40 μm or more, and more preferably 50 μm or more. The distance D2 between the outer peripheral ends 22a and L2a is preferably 1500 μm or less, more preferably 1000 μm or less, more preferably 500 μm or less, and more preferably 300 μm or less. The separation distance D2 in the in-plane direction of the pressure-sensitive adhesive sheet between the outer peripheral end 22a of the pressure-sensitive adhesive layer 22 and the outer peripheral end L1a of the release liner L1 at a position spaced apart from the outer peripheral end L1a in the in-plane direction of the pressure-sensitive adhesive sheet is preferably 10 μm or more, more preferably 30 μm or more, more preferably 40 μm or more, and more preferably 50 μm or more. The distance D2 between the outer peripheral ends 22a, L1a is preferably 1500 μm or less more preferably 1000 μm or less, more preferably 500 μm or less, and still more preferably 300 μm or less.

The psa sheet X2 having the above-described structure can be produced, for example, as follows. First, a release-liner-attached double-sided psa sheet raw material is prepared for forming the psa sheet X2 by punching, cutting, or the like. The release-liner-attached double-sided adhesive sheet stock material has a laminated structure including a preliminary first release liner for forming a release liner L1, a preliminary second release liner for forming a release liner L2, and a preliminary double-sided adhesive sheet main body located between the preliminary first release liner and the preliminary second release liner. The preparatory double-sided adhesive sheet main body has a laminated structure including, for example, a first adhesive layer for forming the adhesive layer 21 on the preparatory first release liner side, a second adhesive layer for forming the adhesive layer 22 on the preparatory second release liner side, and a base material between the first adhesive layer and the second adhesive layer. The adhesive composition for forming the adhesive layer 21 and the method for forming the adhesive layer 21 from the composition, and the adhesive composition for forming the adhesive layer 22 and the method for forming the adhesive layer 22 from the composition are the same as the adhesive composition for forming the adhesive layer 11 and the method for forming the adhesive layer 11 from the composition. Next, the double-sided pressure-sensitive adhesive sheet material with the release liner is subjected to a pressure in the thickness direction thereof, and the pressure-sensitive adhesive sheet material is processed to form the pressure-sensitive adhesive sheet X2 having a desired outer dimension. In a state where the double-sided adhesive sheet material is subjected to a pressure force in the thickness direction, each adhesive layer as an elastic body in the preliminary double-sided adhesive sheet main body of the material is elastically deformable in accordance with the pressure force, and elastically stretches in the in-plane direction of the material at an elongation rate corresponding to the pressure force, and a state where the elastic body elastically bulges out from between the preliminary first release liner or the preliminary second release liner and the base material of the preliminary double-sided adhesive sheet main body can be formed at the outer peripheral end of the material. Examples of the processing means include blanking and/or cutting. Examples of the punching process include a so-called thomson process, i.e., a punching process using a thomson blade. As the cutting process, for example, a so-called milling process can be cited. In this processing step, specifically, the double-sided adhesive sheet raw material with the release liner in a state of being pressurized in the thickness direction is subjected to processing such as punching and/or cutting so that a part or all of the outer peripheral edge of the double-sided adhesive sheet X2 is formed into a new shape by processing to obtain the double-sided adhesive sheet X2 having a target outer dimension. Then, in the pressure-sensitive adhesive sheet X2 obtained by releasing the pressure-sensitive adhesive state, the pressure-sensitive adhesive layers 21 and 22 are restored from the elastically deformed state to the non-deformed state, and the outer peripheral edge of the pressure-sensitive adhesive sheet X2 newly generated in the processing step is set back inward between the release liner L1 or the release liner L2 and the substrate 23. That is, in the produced psa sheet X2, as shown in fig. 4, for example, a part or all of the region of the outer peripheral end 21a of the psa layer 21 is located at a position spaced inward in the psa sheet in-plane direction from the outer peripheral ends L1a, L2a of the release liners L1, L2, and the outer peripheral end 22a of the psa layer 22 is located at a position spaced inward in the psa sheet in-plane direction from the outer peripheral ends L1a, L2a of the release liners L1, L2.

As shown in fig. 4, for example, a part or all of the outer peripheral ends 21a and 22a of the pressure-sensitive adhesive layers 21 and 22 of the pressure-sensitive adhesive sheet main body 20 in the pressure-sensitive adhesive sheet X2 which is a release-liner-equipped double-sided pressure-sensitive adhesive sheet is located at a position spaced from the outer peripheral ends L1a and L2a of the release liners L1 and L2 in the in-plane direction of the pressure-sensitive adhesive sheet. The distance D1 in the adhesive sheet in-plane direction between the outer peripheral end 21a of the adhesive layer 21 located at a position spaced from the outer peripheral ends L1a, L2a of the release liners L1, L2 in the adhesive sheet in-plane direction and the outer peripheral ends L1a, L2a is 5 μm to 2000 μm, respectively, as described above. As described above, the distance D2 in the adhesive sheet in-plane direction between the outer peripheral end 22a of the adhesive layer 22 located at a position spaced apart from the outer peripheral ends L1a, L2a of the release liners L1, L2 in the adhesive sheet in-plane direction and the outer peripheral ends L1a, L2a is 5 μm to 2000 μm, respectively. When the release liner L1 is peeled off from such an adhesive sheet X2, the peeling operation is facilitated if the outer peripheral edge 21a of the adhesive layer 21 of the adhesive sheet main body 20 is located at least at a position (first outer peripheral edge interval position) spaced apart from the outer peripheral edge L1a of the release liner L1 in the adhesive sheet in-plane direction, and the outer peripheral edge 22a of the adhesive layer 22 is located at least at a position (second outer peripheral edge interval position) spaced apart from the outer peripheral edge L2a of the release liner L2 in the adhesive sheet in-plane direction. Specifically, in the first outer peripheral end interval portion, for example, the fingertip of the worker is likely to be brought into contact with the release liner L1 to be peeled without being brought into contact with the adhesive layer 21, and therefore, appropriate deformation for peeling is likely to be started on the release liner L1, and separation of the release liner L1 and the adhesive layer 21 is likely to be started from the end portion of the interface therebetween. In addition, in the second peripheral end spaced portion, for example, since it is easy for the fingertip of the worker to contact the release liner L2 to be peeled without contacting the pressure-sensitive adhesive layer 22, it is easy to start appropriate deformation for peeling on the release liner L2 and start separation of the release liner L2 and the pressure-sensitive adhesive layer 22 from the end portion of the interface therebetween. In this way, the release liners L1 and L2 are easily peeled from the pressure-sensitive adhesive sheet main body 20 by, for example, manual work with respect to the pressure-sensitive adhesive sheet X2.

In addition, when the release liner L1 is peeled off at the first peripheral edge interval portion of the adhesive sheet X2 as described above, it is easy for the operator's fingertips or the like to contact the release liner L1 to be peeled off without contacting the adhesive layer 21. At the same time, at the first peripheral edge interval portion of the adhesive sheet X2, as described above, appropriate deformation for peeling is easily started on the release liner L1 so that separation of the release liner L1 and the adhesive layer 21 to be peeled is started from the end of the interface therebetween. In the second peripheral edge interval portion of the adhesive sheet X2, when the release liner L2 is peeled off as described above, it is easy for the operator's fingertips or the like to contact the release liner L2 to be peeled off without contacting the adhesive layer 22. At the same time, at the second peripheral edge interval portion of the adhesive sheet X2, as described above, it is easy to start appropriate deformation for peeling on the release liner L2 and start separation of the release liner L2 and the adhesive layer 22 from the edge of the interface therebetween. These features are suitable for the pressure-sensitive adhesive sheet X2 in which the release liner can be peeled off at each peripheral edge separation portion, in order to prevent a part of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet main body 20 from being pulled off by the release liner and causing local breakage or defect in the pressure-sensitive adhesive surface or pressure-sensitive adhesive layer when the release liner is peeled off.

In addition, in the psa sheet X2, the distance D1 in the in-plane direction of the psa sheet between the outer peripheral end 21a of the psa layer 21 and the outer peripheral ends L1a, L2a of the release liners L1, L2 at positions spaced apart from the outer peripheral ends L1a, L2a in the in-plane direction of the psa sheet is 5 μm to 2000 μm, respectively, as described above. In the psa sheet X2, the distance D2 in the in-plane direction of the psa sheet between the outer peripheral end 22a of the psa layer 22 and the outer peripheral ends L1a, L2a of the release liners L1, L2 at a position spaced apart from the outer peripheral ends L1a, L2a in the in-plane direction of the psa sheet is 5 μm to 2000 μm, respectively, as described above. The psa sheet X2 having such a configuration is suitable for efficient production by elastic deformation of the psa layer and subsequent shape recovery. The distance of the interval between the outer peripheral ends L1a, L2a of the release liners L1, L2 and the outer peripheral ends 21a, 22a of the adhesive layers 21, 22 (interval distance D1, D2) tends to be in the shorter range of 5 μm to 2000 μm. On the other hand, in order to manufacture a double-sided psa sheet with a release liner having an outer dimension larger than the psa sheet body 20 or the psa layers 21, 22 by 5000 μm or more, for example, after manufacturing a double-sided psa sheet with a release liner having an outer dimension identical to that of the psa sheet body 20 or the psa layers 21, 22 on the psa surfaces 21',22', it is necessary to replace each release liner ( り instead of える) with a release liner having an outer dimension larger than that of the psa sheet body 20 by the above-described range. However, such a method is not efficient from the viewpoint of material cost and the number of steps. The adhesive sheet X2 in which the separation distances D1, D2 between the outer peripheral ends 21a, 22a of the

adhesive layers

21, 22 and the outer peripheral ends L1a, L2a of the release liners L1, L2 at positions spaced apart from the outer peripheral ends L1a, L2a in the in-plane direction of the adhesive sheet are 5 μm to 2000 μm is suitable for efficient production through the above-described process utilizing elastic deformation of the adhesive layer and subsequent shape recovery.

As described above, the pressure-sensitive adhesive sheet X2 which is a double-sided pressure-sensitive adhesive sheet with a release liner is suitable for facilitating the operation of peeling the release liners L1 and L2, suppressing local breakage or chipping of the pressure-

sensitive adhesive layer

21 or 22 at the time of peeling the release liner, and for efficient production. In addition, the pressure-sensitive adhesive sheet X2 in which the separation distances D1 and D2 between the outer peripheral ends 21a and 22a of the pressure-sensitive adhesive layers 21 and 22 and the outer peripheral ends L1a and L2a of the release liners L1 and L2a in the pressure-sensitive adhesive sheet in-plane direction at positions spaced apart from the outer peripheral ends L1a and L2a are 5 μm to 2000 μm is suitable for achieving the size required for the pressure-sensitive adhesive sheet main body 20 while preventing the outer dimension of the pressure-sensitive adhesive sheet X2, that is, the outer dimension of the release liners L1 and L2 from greatly exceeding the size of the pressure-sensitive adhesive sheet main body 20 and becoming excessively large.

As described above, the thicknesses of the pressure-sensitive adhesive layers 21 and 22 in the pressure-sensitive adhesive sheet X2 are each preferably 5 μm or more, more preferably 10 μm or more, more preferably 25 μm or more, more preferably 50 μm or more, more preferably 100 μm or more, and more preferably 200 μm or more. Such a configuration is suitable in order to achieve sufficient adhesive force of the pressure-sensitive adhesive layers 21 and 22 to the adherend. A configuration in which the thickness of the pressure-sensitive adhesive layer 21 is 25 μm or more, preferably 50 μm or more, more preferably 100 μm or more, more preferably 200 μm or more is suitable in terms of ensuring that the separation distance D1 between the outer peripheral ends L1a, L2a of the release liners L1, L2 and the outer peripheral end 21a of the pressure-sensitive adhesive layer 21 is 5 μm or more and longer at the first outer peripheral end separation portion. A configuration in which the thickness of the pressure-sensitive adhesive layer 22 is 25 μm or more, preferably 50 μm or more, more preferably 100 μm or more, more preferably 200 μm or more is suitable in terms of ensuring that the separation distance D2 between the outer peripheral ends L1a, L2a of the release liners L1, L2 and the outer peripheral end 22a of the pressure-sensitive adhesive layer 22 is 5 μm or more and longer at the second outer peripheral end separation portion. The thicker the adhesive layer is, the more the amount of elastic deformation of the adhesive layer in the in-plane direction when the adhesive layer is subjected to a pressing force in the thickness direction tends to increase. On the other hand, from the viewpoint of ease of formation of the pressure-sensitive adhesive layers 21 and 22, the thickness of each of the pressure-sensitive adhesive layers 21 and 22 is preferably 1000 μm or less, more preferably 900 μm or less, and still more preferably 800 μm or less, as described above.

As described above, the storage modulus at 23 ℃ of the adhesive layer 21 is preferably 1.0X 10 ⁴ Pa or more, more preferably 5.0X 10 ⁴ Pa or more, more preferably 1.0X 10 ⁵ Pa or above. Such a configuration is suitable for efficiently producing the psa sheet X2 having the first peripheral edge separation distance D1 of 5 μm to 2000 μm by elastic deformation of the psa layer and subsequent shape recovery. As described above, the storage modulus at 23 ℃ of the adhesive layer 22 is preferably 1.0X 10 ⁴ Pa or more, more preferably 5.0X 10 ⁴ Pa or more, more preferably 1.0X 10 ⁵ Pa or above. Such a configuration is preferable in that the adhesive sheet X2 having the distance D1 between the second peripheral edge separation portions of 5 μm to 2000 μm is efficiently produced by elastic deformation of the adhesive layer and subsequent shape recovery.

Examples

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

[ acrylic oligomer production example of (1)

In a reaction vessel, 60 parts by weight of tetrahydrodicyclopentadiene methacrylate(DCPMA), 40 parts by weight of Methyl Methacrylate (MMA), 3.5 parts by weight of alpha-thioglycerol as a chain transfer agent and 100 parts by weight of toluene as a polymerization solvent were stirred at 70 ℃ for 1 hour under a nitrogen atmosphere. Next, 0.2 parts by weight of 2,2' -azobisisobutyronitrile as a polymerization initiator was added to the mixture in the reaction vessel to prepare a reaction solution, and the reaction was performed at 70 ℃ for 2 hours. Then, the reaction was carried out at 80 ℃ for 2 hours. Then, the reaction solution in the reaction vessel was placed in a temperature atmosphere of 130 ℃ to dry and remove toluene, chain transfer agent and unreacted monomer from the reaction solution. Thus, a solid acrylic oligomer was obtained. The weight average molecular weight (Mw) of the acrylic oligomer is 5.1X 10 ³ 。

[ preparation of acrylic adhesive composition C1 ]

To a monomer mixture containing 78 parts by weight of 2-ethylhexyl acrylate (2 EHA), 18 parts by weight of N-vinyl-2-pyrrolidone (NVP) and 4 parts by weight of 2-hydroxyethyl acrylate (HEA), 0.035 parts by weight of a first photopolymerization initiator (trade name "Irgacure 651", manufactured by basf corporation) and 0.035 parts by weight of a second photopolymerization initiator (trade name "Irgacure 184", manufactured by basf corporation) were added, and then, with respect to the mixture, while measuring its viscosity using a viscosity measuring apparatus, ultraviolet rays were irradiated using an ultraviolet irradiation apparatus until the viscosity of the mixture reached about 20Pa · s. In the viscosity measurement, the rotor rotation speed of the apparatus was set to 10rpm, and the measurement temperature was set to 30 ℃. This gave a partially polymerized prepolymer composition (containing a monomer component which had not undergone polymerization) which was a part of the monomer component in the mixture. Then, 100 parts by weight of this prepolymer composition, 11.8 parts by weight of the above acrylic oligomer, 17.6 parts by weight of 2-hydroxyethyl acrylate (HEA), 0.294 parts by weight of 1,6-hexanediol diacrylate (HDDA), and 0.353 parts by weight of a silane coupling agent (trade name "KBM-403", manufactured by shin-Etsu chemical Co., ltd.) were mixed. Thereby, an acrylic pressure-sensitive adhesive composition (acrylic pressure-sensitive adhesive composition C1) was obtained.

[ preparation of acrylic adhesive composition C2 ]

To a monomer mixture containing 67 parts by weight of n-Butyl Acrylate (BA), 14 parts by weight of cyclohexyl acrylate (CHA) and 19 parts by weight of 4-hydroxybutyl acrylate (HBA), 0.09 parts by weight of a first photopolymerization initiator (trade name "Irgacure 651", manufactured by basf) and 0.09 parts by weight of a second photopolymerization initiator (trade name "Irgacure 184", manufactured by basf) were added, and then, with respect to the mixture, while measuring the viscosity thereof using a viscosity measuring apparatus, ultraviolet rays were irradiated using an ultraviolet irradiation apparatus until the viscosity of the mixture reached about 20Pa · s. In the viscosity measurement, the rotor rotation speed of the apparatus was set to 10rpm, and the measurement temperature was set to 30 ℃. This gave a partially polymerized prepolymer composition (containing a monomer component which had not undergone polymerization) which was a part of the monomer component in the mixture. Then, 100 parts by weight of this prepolymer composition, 9 parts by weight of 2-hydroxyethyl acrylate (HEA), 8 parts by weight of 4-hydroxybutyl acrylate (HBA), 0.12 part by weight of dipentaerythritol hexaacrylate (DPHA) and 0.3 part by weight of a silane coupling agent (trade name "KBM-403", manufactured by shin-Etsu chemical Co., ltd.) were mixed. Thereby, an acrylic pressure-sensitive adhesive composition (acrylic pressure-sensitive adhesive composition C2) was obtained.

[ example 1]

The acrylic adhesive composition C1 was applied to a first release liner (thickness 125 μm, light release type, manufactured by hitto electrical co., ltd.) of polyethylene terephthalate (PET) type to form an adhesive composition layer. Next, a second release liner (thickness 125 μm, heavy release type, manufactured by hitto electrical corporation) of PET was laminated on the adhesive composition layer, and the adhesive composition layer was covered with the liner to block oxygen. In this manner, a laminate having [ first release liner/adhesive composition layer/second release liner ] was obtained]A laminate (laminate L1') obtained by laminating the above components. Next, the laminate L1' was irradiated from the first release liner side with a black light lamp (manufactured by Toshiba, ltd.) for 300 seconds at an illuminance of 3mW/cm ² Ultraviolet rays of (1). Thereby curing the adhesive composition layer of the laminate L1' to form an adhesive layer, thereby obtaining a laminate having [ first release liner/adhesive layer/secondTwo release liners]A laminate (laminate L1) having the above-described laminated structure. The thickness of the pressure-sensitive adhesive layer in the laminate L1 was 500. Mu.m. Subsequently, the laminate L1 was subjected to thomson processing. Specifically, the laminate L1 was punched out to a size of 11.6 inches (long side 196.4mm × short side 104 mm) using a punching machine and a thomson blade. In this process, a thomson blade which is brought into contact with the laminate L1 and performs punching is subjected to punching in which a new entire outer peripheral end of the laminate L1 is formed while applying a pressure to the laminate L1 in the thickness direction of the laminate L1. A double-sided adhesive sheet of example 1 having a laminated structure including a pair of release liners and a double-sided adhesive sheet main body (adhesive layer) therebetween was produced in the manner described above. The outer peripheral ends of the first release liner and the second release liner of the double-sided adhesive sheet of example 1 were located at the same position in the adhesive sheet in-plane direction. The outer peripheral edge of the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet of example 1 is located within a range of 5 to 2000 μm from the outer peripheral edge of the first release liner and the second release liner to the inner side in the in-plane direction of the pressure-sensitive adhesive sheet. In the long side of the double-sided adhesive sheet of example 1, the average of the longest distance and the shortest distance in the interval in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average interval distance in the long side) was 47 μm. Of the short sides of the double-sided adhesive sheet of example 1, the average of the longest distance and the shortest distance in the interval in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average interval distance in the short sides) was 38 μm.

[ example 2]

Milling was performed on 10 superposed double-sided adhesive sheets of example 1 in alignment. Specifically, first, a laminate of 10 double-sided adhesive sheets of example 1 was sandwiched between a pair of sandwiching plates included in a vise-structured jig so that a pressure force can be applied between the sandwiching plates in the thickness direction while the laminate was exposed at and near the outer peripheral end thereof. Then, the pressure applied between the sandwiching plates in the thickness direction of the laminate was adjusted so that the adhesive derived from the adhesive layer partially expanded outward at the outer peripheral end of the laminate, and the entire outer peripheral end of the laminate was cut with a rotary blade with a cutting amount of 1.0 mm. The laminate is then released from the compressive force between the jaws. A double-sided adhesive sheet of example 2 having a laminated structure including a pair of release liners and a double-sided adhesive sheet main body (adhesive layer) therebetween was produced in the manner described above. The outer peripheral ends of the first release liner and the second release liner of the double-sided adhesive sheet of example 2 were located at the same position in the adhesive sheet in-plane direction. The outer peripheral end of the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet of example 2 is located within a range of 5 μm to 2000 μm inward from the outer peripheral ends of the first release liner and the second release liner in the in-plane direction of the pressure-sensitive adhesive sheet. In the long side of the double-sided adhesive sheet of example 2, the average of the longest distance and the shortest distance in the interval in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average interval distance in the long side) was 170 μm. In the short side of the double-sided adhesive sheet of example 2, the average of the longest distance and the shortest distance in the interval in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average interval distance in the short side) was 135 μm.

[ example 3]

A double-sided adhesive sheet of example 3 having a laminated structure including a pair of release liners and a double-sided adhesive sheet main body (adhesive layer) therebetween was produced in the same manner as in example 1, except that the acrylic adhesive composition C2 was used instead of the acrylic adhesive composition C1, and the thickness of the adhesive layer formed was set to 250 μm instead of 500 μm. The outer peripheral ends of the first release liner and the second release liner of the double-sided adhesive sheet of example 3 were in the same position in the adhesive sheet in-plane direction. The outer peripheral end of the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet of example 3 was located within a range of 5 μm to 2000 μm inward from the outer peripheral ends of the first release liner and the second release liner in the in-plane direction of the pressure-sensitive adhesive sheet. In the long side of the double-sided adhesive sheet of example 3, the average of the longest distance and the shortest distance in the interval in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average interval distance in the long side) was 11 μm. In the short sides of the double-sided adhesive sheet of example 3, the average of the longest distance and the shortest distance in the interval in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average interval distance in the short sides) was 13 μm.

[ example 4]

A double-sided adhesive sheet of example 4 having a laminated structure including a pair of release liners and a double-sided adhesive sheet main body (adhesive layer) therebetween was produced in the same manner as in example 2 except that the double-sided adhesive sheet of example 3 was used instead of the double-sided adhesive sheet of example 1. The outer peripheral ends of the first release liner and the second release liner of the double-sided adhesive sheet of example 4 were in the same position in the adhesive sheet in-plane direction. The outer peripheral end of the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet of example 4 is located within a range of 5 μm to 2000 μm inward from the outer peripheral ends of the first release liner and the second release liner in the in-plane direction of the pressure-sensitive adhesive sheet. In the long side of the double-sided adhesive sheet of example 4, the average of the longest distance and the shortest distance in the interval in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average interval distance in the long side) was 170 μm. In the short sides of the double-sided adhesive sheet of example 4, the average of the longest distance and the shortest distance in the interval in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average interval distance in the short sides) was 150 μm.

[ example 5]

< formation of first adhesive layer >

The acrylic pressure-sensitive adhesive composition C1 was applied to one side of a substrate obtained by subjecting both sides of a polyethylene terephthalate film (trade name "COSMOSHINE SRF", manufactured by toyobo co., ltd.) having a thickness of 80 μm to corona treatment, thereby forming a pressure-sensitive adhesive composition layer. Next, a first release liner of PET (thickness 125 μm, light release type, manufactured by hitto electrical corporation) was further laminated on the adhesive composition layer, covering the adhesive composition layer to block oxygen. In this manner, a laminate having [ first release liner/adhesive composition layer/substrate ] was obtained]A laminate (laminate L2') formed by laminating the layers. Then, the black light lamp (Toshiba, ltd.) was used from the fourth placeThe laminate L2' was irradiated with a peeling liner for 300 seconds at an illuminance of 3mW/cm ² Ultraviolet rays of (1). The adhesive composition layer of the laminate L2' was thereby cured to form an adhesive layer (first adhesive layer), thereby obtaining a laminate having [ first release liner/adhesive layer (first adhesive layer)/substrate]A laminate (laminate L2) comprising the above laminates. The thickness of the first adhesive layer in the laminate L2 was 100 μm.

< formation of second adhesive layer >

The acrylic adhesive composition C1 was applied to a PET-based third release liner (thickness 125 μm, light release type, manufactured by hitto electrical corporation) to form an adhesive composition layer. Next, a second release liner (thickness 125 μm, heavy release type, manufactured by ritto electrical corporation) of PET was further laminated on the adhesive composition layer, and the adhesive composition layer was covered to block oxygen. In this manner, a laminate having [ third release liner/adhesive composition layer/second release liner ] was obtained]A laminate (laminate L3') obtained by laminating the layers. Next, the laminate L3' was irradiated from the third release liner side with a black light lamp (Toshiba, ltd.) for 300 seconds at an illuminance of 3mW/cm ² Ultraviolet rays of (1). The adhesive composition layer of the laminate L3' was thereby cured to form an adhesive layer (second adhesive layer), thereby obtaining a laminate having [ third release liner/adhesive layer (second adhesive layer)/second release liner [ ]]A laminate (laminate L3) formed by laminating the layers. The thickness of the second adhesive layer in the laminate L3 was 500 μm.

< preparation of double-sided adhesive sheet >

The third release liner was peeled from the laminate L3 (third release liner/second adhesive layer/second release liner), and then the second adhesive layer with the release liner on one side was laminated to the exposed surface of the base material of the laminate L2 via the surface of the second adhesive layer exposed by the peeling. Thus, a laminate (laminate L4) having a laminate structure of [ first release liner/first pressure-sensitive adhesive layer (thickness 100 μm)/base material (thickness 80 μm)/second pressure-sensitive adhesive layer (thickness 500 μm)/second release liner ] was obtained. Next, this laminate L4 was subjected to thomson processing in the same manner as in example 1, to produce a double-sided adhesive sheet of example 5 having a laminate structure including a pair of release liners and a double-sided adhesive sheet main body (first adhesive layer/substrate/second adhesive layer) therebetween. The outer peripheral ends of the first release liner and the second release liner of the double-sided adhesive sheet of example 5 were in the same position in the adhesive sheet in-plane direction. The outer peripheral end of the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet of example 5 was located within a range of 5 μm to 2000 μm inward from the outer peripheral ends of the first release liner and the second release liner in the in-plane direction of the pressure-sensitive adhesive sheet. In the long side of the double-sided adhesive sheet of example 5, the average of the longest distance and the shortest distance in the interval in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average interval distance in the long side) was 53 μm. In the short side of the double-sided adhesive sheet of example 5, the average of the longest distance and the shortest distance in the interval in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average interval distance in the short side) was 27 μm.

[ example 6]

A double-sided adhesive sheet of example 6 having a laminated structure including a pair of release liners and a double-sided adhesive sheet main body (first adhesive layer/substrate/second adhesive layer) therebetween was produced in the same manner as in example 2 except that the double-sided adhesive sheet 10 sheet of example 5 was used instead of the double-sided adhesive sheet 10 sheet of example 1. The outer peripheral ends of the first release liner and the second release liner of the double-sided adhesive sheet of example 6 were in the same position in the adhesive sheet in-plane direction. The outer peripheral end of the pressure-sensitive adhesive layer of the double-sided pressure-sensitive adhesive sheet of example 6 was located within a range of 5 μm to 2000 μm inward from the outer peripheral ends of the first release liner and the second release liner in the in-plane direction of the pressure-sensitive adhesive sheet. In the long side of the double-sided adhesive sheet of example 6, the average of the longest distance and the shortest distance in the intervals in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average distance of intervals in the long side) was 113 μm. In the short sides of the double-sided adhesive sheet of example 6, the average of the longest distance and the shortest distance in the interval in the in-plane direction of the adhesive sheet between the outer peripheral end of the adhesive layer and the outer peripheral end of the release liner (average interval distance in the short sides) was 130 μm.

Comparative example 1

A release-liner-attached double-sided adhesive sheet of comparative example 1 was produced in the same manner as in example 1 except that cutting processing using a dicing blade was performed instead of thomson processing. In the outer peripheral end of the double-sided adhesive sheet of comparative example 1, the adhesive layer protruded from between the release liners.

Comparative example 2

A release-liner-attached double-sided adhesive sheet of comparative example 2 was produced in the same manner as in example 3 except that dicing using a dicing blade was performed instead of thomson processing. In the outer peripheral end of the double-sided adhesive sheet of comparative example 2, the adhesive layer protruded from between the release liners.

< storage modulus of adhesive layer >

The storage modulus of each pressure-sensitive adhesive layer in each double-sided pressure-sensitive adhesive sheet of examples and comparative examples was determined by dynamic viscoelasticity measurement. In the preparation of the measurement sample for dynamic viscoelasticity measurement, first, a required number of laminates (laminates L1) having a laminate structure of [ first release liner/adhesive layer/second release liner ] were prepared for each pressure-sensitive adhesive layer to be measured in the same manner as the laminate L1 of example 1. The thickness of each pressure-sensitive adhesive layer in the laminate L1 prepared for each measurement object in the required number is the same as the thickness of the pressure-sensitive adhesive layer to be measured. Next, the release liner was peeled from each of the laminates L1 thus produced, and the adhesive layers were sequentially bonded to each other. In this manner, a laminated adhesive layer sheet having a thickness of about 2mm was produced for each adhesive layer to be measured. Then, the laminated adhesive layer sheet was punched out to obtain cylindrical pellets (diameter 7.9 mm), which were used as a measurement sample. The prepared samples for measurement were fixed to a parallel plate jig having a diameter of 7.9mm using a dynamic viscoelasticity measuring apparatus (trade name "ARES", manufactured by Rheometric Co., ltd.), and then dynamic viscoelasticity was measured. In this measurement, the measurement mode was set to the shear mode, the measurement temperature range was set to-70 ℃ to 150 ℃, the temperature increase rate was set to 5 ℃/min, and the frequency was set to 1Hz. Thus, the temperature dependence of the storage modulus G' of each sample for measurement was measured. The values of storage modulus (G') at 23 ℃ of each adhesive layer in each double-sided adhesive sheet of examples and comparative examples are shown in tables 1 and 2.

< breakage/defect of adhesive layer upon release of Release liner >

With respect to each of the double-sided adhesive sheets of examples and comparative examples, the presence or absence of breakage or chipping of the adhesive layer at the time of peeling of the release liner was examined. Specifically, when a light release type release liner of a pair of release liners attached to a double-sided adhesive sheet was manually peeled off, the case where no adhesive was adhered to the peeled release liner was evaluated as good (o), and the case where adhesive was adhered to the peeled release liner was evaluated as bad (x).

[ evaluation ]

The double-sided adhesive sheets of examples 1 to 6 having the configuration of the present invention each suppressed local breakage or chipping of the adhesive layer when the release liner was peeled off. In contrast, in both of the double-sided pressure-sensitive adhesive sheets of comparative examples 1 and 2, local breakage or chipping of the pressure-sensitive adhesive layer occurred when the release liner was peeled off.

Claims

1. A double-sided adhesive sheet, wherein,

the double-sided adhesive sheet has a laminated structure comprising a first release liner, a second release liner, and a double-sided adhesive sheet main body having an adhesive layer and disposed between the first release liner and the second release liner,

at least a partial region of the outer peripheral end of the adhesive layer is located at a position that is 5 μm or more and less than 500 μm inward from the outer peripheral end of the first release liner and the outer peripheral end of the second release liner in the adhesive sheet in-plane direction,

the adhesive layer has a thickness of 25 μm or more, and

the adhesive layer has a storage modulus at 23 ℃ of 1.0X 10 ⁵ Pa or above.

2. The double-sided adhesive sheet according to claim 1, wherein the outer peripheral end of the adhesive layer is located at a position that is 5 μm or more and less than 500 μm inward from the outer peripheral ends of the first and second release liners in the adhesive sheet in-plane direction.

3. The double-sided adhesive sheet according to claim 1, wherein the adhesive layer is a cured product of an active energy ray-curable adhesive composition.

4. The double-sided adhesive sheet according to claim 1, wherein the double-sided adhesive sheet body has a haze of 3% or less.