JP2021080425A - Adhesive sheet - Google Patents

Abstract

To provide an adhesive sheet having an adhesive layer which is excellent in adhesive force and suppresses deterioration with time of the adhesive force.SOLUTION: The adhesive sheets 1A and 1B have base materials 10 and adhesive layers. The adhesive layer is a layer formed from an adhesive composition containing a styrenic resin (A) and a tackifier resin (B). The styrenic resin (A) contains an SI resin and an SIS resin. A content of the SIS resin is 35 mass% or more based on the total amount of the styrenic resin (A). The tackifier resin (B) contains one or more selected from a rosin-based resin and a non-hydrogenated terpene-based resin having no aromatic structure. A mass ratio [(B)/(A)] of the tackifier resin (B) to the styrenic resin (A) is 1.0 or less, and a mass ratio [(B)/(SIS)] of the tackifier resin (B) to the SIS resin in the styrenic resin (A) is less than 2.5.SELECTED DRAWING: Figure 1

Description

The present invention relates to an adhesive sheet.

The adhesive sheet is used when fixing various adherends.
In addition, the adhesive sheet is used as a binding adhesive tape for binding various articles, and as a display label (also referred to as an identification label) or a tag for displaying the destination or contents by wrapping it around various cables, cords, pipes, etc. Is also used.

By the way, in recent years, various materials for an adhesive for forming an adhesive layer of an adhesive sheet have been studied. One such material is a styrene resin containing a styrene-isoprene block copolymer and a styrene-isoprene-styrene triblock copolymer. Since the styrene-based resin forms a polystyrene phase by physical cross-linking, it exhibits a high cohesive force near room temperature. It also has excellent wettability. On the other hand, since the styrene-based resin itself does not have adhesive strength, a pressure-sensitive adhesive layer having excellent adhesive strength is formed by adding a tack-imparting resin to the styrene-based resin. For example, in Patent Document 1, 100 parts by mass of an aliphatic aromatic copolymer resin and 30 parts by mass of an aromatic-modified terpene resin are added as a tackifier resin to 100 parts by mass of the styrene resin to provide an adhesive layer. (See Example 1 of Cited Document 1).

Japanese Unexamined Patent Publication No. 2014-24457

However, as a result of diligent studies by the present inventors, the pressure-sensitive adhesive layer formed by using the pressure-sensitive adhesive composition obtained by mixing the pressure-imparting resin with the styrene-based resin is until the pressure-sensitive adhesive layer is attached to the adherend. Alternatively, it was found that the adhesive strength may decrease with time until the adhesive layers are bonded to each other.

The present invention has been made in view of the above problems, and is a pressure-sensitive adhesive containing a styrene-based resin containing a styrene-isopregen block copolymer and a styrene-isoprene-styrene triblock copolymer, and a tackifier resin. The pressure-sensitive adhesive sheet having the pressure-sensitive adhesive layer formed from the composition has excellent adhesive strength, and the pressure-sensitive adhesive strength until the pressure-sensitive adhesive layers are attached to the adherend or until the pressure-sensitive adhesive layers are bonded to each other. It is an object of the present invention to provide a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer in which a decrease with time is suppressed.
In the present specification, "the decrease in adhesive strength with time until the adhesive layer is attached to the adherend or the adhesive layers are attached to each other" is simply referred to as "adhesiveness". It is also called "decrease in power over time".

As a result of diligent studies, the present inventors set the content of the styrene-isoprene-styrene triblock copolymer in the styrene resin within a specific range, and set the tackifier resin and the styrene resin to each other. The above problems can be solved by setting the mass ratio to a specific range and setting the mass ratio of the tackifier resin to the styrene-isoprene-styrene triblock copolymer in the styrene resin to a specific range. This has led to the completion of the present invention.

That is, the present invention relates to the following [1] to [9].
[1] A pressure-sensitive adhesive sheet having a base material and a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition containing a styrene-based resin (A) and a pressure-sensitive adhesive resin (B). It is a layer, and the styrene resin (A) contains a styrene-isopregen block copolymer (SI) and a styrene-isoprene-styrene triblock copolymer (SIS), and the styrene-isoprene-styrene triblock The content of the copolymer (SIS) is 35% by mass or more based on the total amount of the styrene-based resin (A), and the tackifier resin (B) does not have a rosin-based resin and an aromatic structure. The mass ratio [(B) / (A)] of the pressure-sensitive adhesive resin (B) to the styrene-based resin (A) is 1.0 or less, including one or more selected from hydride terpene-based resins. The mass ratio [(B) / (SIS)] of the pressure-sensitive adhesive resin (B) to the styrene-isoprene-styrene triblock copolymer (SIS) in the styrene resin (A) is 2.5. Adhesive sheet that is less than.
[2] The pressure-sensitive adhesive sheet according to [1], wherein the mass ratio [(B) / (A)] of the pressure-sensitive adhesive resin (B) to the styrene-based resin (A) is less than 1.0.
[3] The mass ratio [(B) / (AI)] of the tackifier resin (B) to the isoprene-derived structural unit (AI) in the styrene resin (A) is 1.2. The adhesive sheet according to [1] or [2], which is as follows.
[4] The content of the styrene-derived structural unit (AS) in the styrene-based resin (A) is less than 25% by mass based on the total amount of the structural units of the styrene-based resin (A). The adhesive sheet according to any one of 1] to [3].
[5] The pressure-sensitive adhesive sheet according to any one of [1] to [4], which is used by sticking the pressure-sensitive adhesive surfaces of the pressure-sensitive adhesive layer to each other.
[6] The pressure-sensitive adhesive sheet according to any one of [1] to [5], which has a structure in which the pressure-sensitive adhesive layer is laminated on a part of the surface of the base material.
[7] The pressure-sensitive adhesive sheet according to [6], wherein the pressure-sensitive adhesive layer laminated on a part of the surface of the base material is present at two or more places.
[8] The pressure-sensitive adhesive sheet according to [6], wherein a part of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer is exposed at two or more places, or can be displayed at two or more places.
[9] The adhesive sheet according to any one of [1] to [8], which is wrapped around an object and used as an identification label or tag.

According to the present invention, it has a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing a styrene-based resin containing a styrene-isopregen block copolymer and a styrene-isoprene-styrene triblock copolymer and a pressure-sensitive adhesive resin. The adhesive sheet has excellent adhesive strength, and the adhesive strength is suppressed from decreasing with time until the adhesive layer is attached to the adherend or the adhesive layers are attached to each other. It becomes possible to provide an adhesive sheet having a layer.

It is sectional drawing of the adhesive sheet of 1st Embodiment which shows an example of the structure of the adhesive sheet of this invention. It is sectional drawing of the adhesive sheet of 2nd aspect which shows an example of the structure of the adhesive sheet of this invention. It is sectional drawing of the adhesive sheet of 3rd Embodiment which shows an example of the structure of the adhesive sheet of this invention. It is sectional drawing of the adhesive sheet of 4th aspect which shows an example of the structure of the adhesive sheet of this invention.

[Aspects of the adhesive sheet of the present invention]
The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having a base material and a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer contains a styrene resin (A) and a pressure-sensitive adhesive resin (B). It is a layer formed from.
The styrene-based resin (A) contains a styrene-isopregen block copolymer (SI) and a styrene-isoprene-styrene triblock copolymer (SIS), and the styrene-isoprene-styrene triblock copolymer (SIS). The content of SIS) is 35% by mass or more based on the total amount of the styrene resin (A).
The tackifier resin (B) contains one or more selected from a rosin-based resin and a non-hydrogenated terpene-based resin having no aromatic structure.
The mass ratio [(B) / (A)] of the tackifier resin (B) and the styrene resin (A) is 1.0 or less.
The mass ratio [(B) / (SIS)] of the tackifier resin (B) and the styrene-isoprene-styrene triblock copolymer (SIS) in the styrene resin (A) is less than 2.5. Is.

As a result of diligent studies, the present inventors have excellent adhesive strength by forming a pressure-sensitive adhesive layer from a pressure-sensitive adhesive composition satisfying the above requirements, and a pressure-sensitive adhesive in which a decrease in adhesive strength with time is suppressed. I found that I could do it as a layer.
The reason why the pressure-sensitive adhesive layer can be formed with excellent adhesive strength and suppressed decrease in adhesive strength with time is that the styrene resin (A) is formed by forming the pressure-sensitive adhesive layer from the pressure-sensitive adhesive composition satisfying the above requirements. The motility of the isoprene domain inside is reduced, the compatible state of the tackifier resin (B) with the isoprene domain is stably maintained, and the bleed-out of the tackifier resin (B) to the surface layer of the pressure-sensitive adhesive layer is suppressed. It is presumed that this is the reason.

Hereinafter, the structure of the pressure-sensitive adhesive sheet of the present invention, the members (base material, pressure-sensitive adhesive layer, release liner, and non-adhesive layer) constituting the pressure-sensitive adhesive sheet of the present invention, the method for producing the pressure-sensitive adhesive sheet of the present invention, and the present invention. The use of the adhesive sheet will be described in detail.

<Composition of adhesive sheet>
The pressure-sensitive adhesive sheet of the present invention has a base material and a pressure-sensitive adhesive layer.
The pressure-sensitive adhesive sheet according to one aspect of the present invention may be a pressure-sensitive adhesive sheet composed of only a base material and a pressure-sensitive adhesive layer, but may have layers other than these. For example, a release liner may be further laminated on the adhesive surface of the adhesive layer.
Further, the pressure-sensitive adhesive sheet according to one aspect of the present invention may have a structure in which the base material and the pressure-sensitive adhesive layer are directly laminated, but may have a structure in which another layer is provided between the base material and the pressure-sensitive adhesive layer. May be good.

1 to 4 show a schematic cross-sectional view of the pressure-sensitive adhesive sheet according to the first to fourth aspects as an example of the structure of the pressure-sensitive adhesive sheet of the present invention.

As the pressure-sensitive adhesive sheet of one aspect of the present invention, a pressure-sensitive adhesive sheet having a structure in which a pressure-sensitive adhesive layer is laminated on a part of the surface of the base material is preferable, and there are two or more pressure-sensitive adhesive layers laminated on a part of the surface of the base material. The existing adhesive sheet is more preferred.
Examples of the pressure-sensitive adhesive sheet of such an embodiment include the pressure-sensitive adhesive sheet of the first aspect of FIG. 1 and the pressure-sensitive adhesive sheet of the second aspect of FIG.

Further, as another aspect of the pressure-sensitive adhesive sheet of the present invention, there is a pressure-sensitive adhesive sheet in which a part of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer is exposed at two or more places, or can be displayed at two or more places. .. In the pressure-sensitive adhesive sheet of this aspect, the exposed or exposed adhesive surfaces are bonded to each other.
Examples of the pressure-sensitive adhesive sheet of such an embodiment include the pressure-sensitive adhesive sheet of the third aspect of FIG. 3 and the pressure-sensitive adhesive sheet of the fourth aspect of FIG.

Hereinafter, the pressure-sensitive adhesive sheet according to the first to fourth aspects shown in FIGS. 1 to 4 will be described in detail.

(First aspect of the pressure-sensitive adhesive sheet of the present invention)
In the pressure-sensitive adhesive sheet 1A shown in FIG. 1A, which is the first aspect of the present invention, the first pressure-sensitive adhesive layer 21 and the second pressure-sensitive adhesive layer 22 are laminated on both ends of one surface 10b of the base material 10. Has a configuration.
The pressure-sensitive adhesive sheet 1A shown in FIG. 1A is preferably used by adhering the pressure-sensitive adhesive surface 21a of the first pressure-sensitive adhesive layer 21 and the pressure-sensitive adhesive surface 22a of the second pressure-sensitive adhesive layer 22. Here, when the adhesive surfaces of the two pressure-sensitive adhesive layers are bonded to each other, it is preferable that the surface 10b of the base material 10 is on the inside and the surface 10a is on the outside.
For example, when the adhesive sheet 1A is attached to various cables and cords, the adhesive sheet 1A has a structure in which an adhesive layer is laminated on a part of the surface 10b of the base material 10, so that the various cables and cords are based on the adhesive sheet 1A. The surfaces 10b of the material 10 come into contact with each other.
Here, when the adhesive surfaces of the two adhesive layers of the adhesive sheet 1A are bonded to each other, since there is no adhesive surface on the surface 10b side of the base material, various cables and various cables due to the adhesion of the adhesive layers It is possible to prevent contamination of the adherend such as a cord. Further, since the adhesive strength of the pressure-sensitive adhesive layers is unlikely to decrease with time and the adhesive strength is excellent until the pressure-sensitive adhesive layers are bonded to each other, the pressure-sensitive adhesive layers are bonded to each other after being stored for a long period of time. Even when used together, the adhesive sheet is unlikely to fall off from the adherend.

When the pressure-sensitive adhesive sheet 1A is used as an identification label, it is preferable that various information for identification is described or can be described on the surface 10a of the base material 10.

Further, in the pressure-sensitive adhesive sheet of one aspect of the present invention, as in the pressure-sensitive adhesive sheet 1B shown in FIG. 1B, the release liner 31 is further placed on the pressure-sensitive adhesive surfaces of the first pressure-sensitive adhesive layer 21 and the second pressure-sensitive adhesive layer 22. 32 may be laminated.
The pressure-sensitive adhesive sheet 1B shown in FIG. 1B has two release liners 31 and 32, and one release liner adheres to the first pressure-sensitive adhesive layer 21 and the second pressure-sensitive adhesive layer 22. It may be a structure laminated on the surface.

(Second aspect of the pressure-sensitive adhesive sheet of the present invention)
In the pressure-sensitive adhesive sheet 2A shown in FIG. 2A, which is the second aspect of the present invention, the first pressure-sensitive adhesive layer 21 is laminated on one end of one surface 10a of the base material 10, and the first of the other surface 10b. The second pressure-sensitive adhesive layer 22 is laminated on one end opposite to the pressure-sensitive adhesive layer 21 side.
The pressure-sensitive adhesive sheet 2A is also used by adhering the pressure-sensitive adhesive surface 21a of the first pressure-sensitive adhesive layer 21 and the pressure-sensitive adhesive surface 22a of the second pressure-sensitive adhesive layer 22.

When the adhesive surface 21a and the adhesive surface 22a are attached, the adhesive surfaces of the two adhesive layers may be attached to each other so that the surface 10a of the base material 10 is located on the outside depending on the method of attachment. Also, the adhesive surfaces of the two adhesive layers can be bonded to each other so that the surface 10b is located on the outside.
Therefore, when the pressure-sensitive adhesive sheet 2A is used as an identification label, it is preferable that various information for identification is described or can be described on at least one surface of the base material 10.

Further, the pressure-sensitive adhesive sheet 2A may have a configuration in which various information for identification different from each other is described or can be described on the surface 10a and the surface 10b of the base material 10.
In the case of the pressure-sensitive adhesive sheet 2A having such a configuration, the surface of the base material 10 located on the outside can be changed by selecting the method of bonding the pressure-sensitive adhesive surfaces to each other. Information can be displayed on the outside.

Also in the adhesive sheet 2A of FIG. 2A, as in the adhesive sheet 2B shown in FIG. 2B, a release liner is further formed on the adhesive surfaces of the first adhesive layer 21 and the second adhesive layer 22. 31 and 32 may be laminated.

(Third aspect of the pressure-sensitive adhesive sheet of the present invention)
In the pressure-sensitive adhesive sheet 3 shown in FIG. 3A, which is the third aspect of the present invention, the base material 10, the pressure-sensitive adhesive layer 20, and the release liner 30 are laminated in this order, and the release liner 30 is the cut portion X1. , X2.
The cut portions X1 and X2 of the release liner 30 are provided so that the release liner ends 301 and 302 at both ends of the release liner 30 can be removed, respectively.

FIG. 3B is a schematic cross-sectional view of the pressure-sensitive adhesive sheet 3 showing a state after removing the release liner end portions 301 and 302 along the cut portions X1 and X2, respectively.
As shown in FIG. 3B, the adhesive sheet 3 is a part of the adhesive surface of the adhesive layer 20 by removing the release liner end portions 301 and 302 along the cut portions X1 and X2, respectively. The two adhesive surfaces 201a and 202a can be exposed.

The pressure-sensitive adhesive sheet 3 shown in FIG. 3 is preferably used by sticking the pressure-sensitive adhesive surface 201a and the pressure-sensitive adhesive surface 202a that are exposed after removing the release liner end portions 301 and 302, respectively.
In the pressure-sensitive adhesive sheet 3, the two pressure-sensitive adhesive surfaces are bonded to each other so that the surface 10a of the base material 10 is located on the outside. Therefore, various information for identification is described on the surface 10a of the base material 10. It is preferable that it can be described.
Further, when the exposed adhesive surfaces of the adhesive sheet 3 are bonded to each other, the release liner 30 is located inside. Therefore, when the adhesive sheet 3 is attached to various cables and cords, it is possible to prevent contamination of the adherends of the various cables and cords due to the adhesion of the adhesive layer. Further, since the adhesive strength of the pressure-sensitive adhesive layers is unlikely to decrease with time and the adhesive strength is excellent until the pressure-sensitive adhesive layers are bonded to each other, the pressure-sensitive adhesive layers are bonded to each other after being stored for a long period of time. Even when used together, the adhesive sheet is unlikely to fall off from the adherend.

(Fourth Aspect of Adhesive Sheet of the Present Invention)
The pressure-sensitive adhesive sheet 4 shown in FIG. 4, which is a fourth aspect of the present invention, has a base material 10, a pressure-sensitive adhesive layer 20, and a non-sticky layer 40, and is not formed on a part of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer 20. The adhesive layers are laminated, and the two adhesive surfaces 201a and 202a, which are a part of the adhesive surface of the adhesive layer 20, are exposed.
Although the pressure-sensitive adhesive surfaces 201a and 202a of the pressure-sensitive adhesive sheet 4 shown in FIG. 4 are exposed, the pressure-sensitive adhesive sheet 4 may have a structure in which a release liner is laminated on these pressure-sensitive adhesive surfaces. In the pressure-sensitive adhesive sheet of this aspect, the pressure-sensitive adhesive surfaces 201a and 202a can be exposed by removing the release liner.

The adhesive sheet 4 shown in FIG. 4 is used by adhering the exposed adhesive surface 201a and the adhesive surface 202a.
In this pressure-sensitive adhesive sheet 4, the two pressure-sensitive adhesive surfaces are bonded to each other so that the surface 10a of the base material 10 is located on the outside. Therefore, various information for identification is described on the surface 10a of the base material 10. It is preferable that it can be described.
Further, when the exposed adhesive surfaces of the adhesive sheet 4 are bonded to each other, the non-adhesive layer 40 is located inside.
Since the surface of the non-adhesive layer 40 does not have adhesiveness, when the adhesive sheet 4 is attached to various cables and cords, the adhesive layer adheres to the adherends of various cables and cords. Can prevent contamination. Further, since the adhesive strength of the pressure-sensitive adhesive layers is unlikely to decrease with time and the adhesive strength is excellent until the pressure-sensitive adhesive layers are bonded to each other, the pressure-sensitive adhesive layers are bonded to each other after being stored for a long period of time. Even when used together, the adhesive sheet is unlikely to fall off from the adherend.

(Preferable requirements for the pressure-sensitive adhesive sheet according to one aspect of the present invention)
In the pressure-sensitive adhesive sheet of one aspect of the present invention, the shape of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layers to be bonded to each other from the viewpoint of preventing them from being contaminated by the pressure-sensitive adhesive surface after being attached to an adherend such as various cables and cords. However, it is preferable that they are substantially the same as each other.
For example, in the pressure-sensitive adhesive sheet 1A of FIG. 1A and the pressure-sensitive adhesive sheet 2A of FIG. 2B, the pressure-sensitive adhesive surface 21a of the first pressure-sensitive adhesive layer 21 and the pressure-sensitive adhesive surface 22a of the second pressure-sensitive adhesive layer 22 are attached to each other. It is preferable that the shapes are substantially the same.
Further, in the pressure-sensitive adhesive sheet 3 of FIG. 3 and the pressure-sensitive adhesive sheet 4 of FIG. 4, it is preferable that the exposed or expressable adhesive surface 201a and the adhesive surface 202a have substantially the same shape.
In addition, in this specification, "the shape of the adhesive surface of the adhesive layer to be bonded to each other is substantially the same as each other" means that the area of the common portion that overlaps when the two target adhesive surfaces are overlapped with each other. It means that the area ratio of the portion having a different shape to 100% is less than 10%.

The pressure-sensitive adhesive sheet of the present invention has excellent adhesive strength between the pressure-sensitive adhesive layers, and in particular, when the pressure-sensitive adhesive surfaces of the pressure-sensitive adhesive layers are bonded to each other, the adhesive strength between the adhesive surfaces is high. Moreover, since the adhesive strength of the pressure-sensitive adhesive layers is unlikely to decrease with time until the pressure-sensitive adhesive layers are bonded to each other, the pressure-sensitive adhesive layers were used after being stored for a long period of time. Even in this case, it is difficult to peel off and can be suitably used as an identification label, a tag, or the like.

In the pressure-sensitive adhesive sheet of one aspect of the present invention, the adhesive strength between the pressure-sensitive adhesive surfaces when the pressure-sensitive adhesive surfaces of the pressure-sensitive adhesive layers are bonded to each other is preferably 40.0 N / 25 mm or more, more preferably 45.0 N / 25 mm or more. , More preferably 48.0 N / 25 mm or more, and even more preferably 50.0 N / 25 mm or more.
In this specification, the adhesive strength between the adhesive surfaces means a value measured based on the method described in the examples.
Further, the adhesive strength between the adhesive surfaces when the adhesive surfaces of the adhesive layer are bonded to each other after being allowed to stand in a high temperature environment of 70 ° C. for 3 days is also preferably within the above range.

<Base material>
The base material contained in the pressure-sensitive adhesive sheet of the present invention is appropriately selected depending on the intended use, and examples thereof include a paper base material, a metal base material, a porous base material such as a non-woven fabric, and a resin film.

Examples of the paper material constituting the paper base material include high-quality paper, coated paper, art paper, glassin paper, kraft paper, impregnated paper, medium-quality paper, sulfated paper, and thin leaf paper.

Examples of the metal constituting the metal base material include aluminum, copper, silver, and gold.

Examples of the resin constituting the resin film include polyester resins such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; polyolefin resins such as polyethylene and polypropylene; polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, and ethylene-vinyl acetate. Vinyl-based resins such as copolymers and ethylene-vinyl alcohol copolymers; polystyrene; acrylonitrile-butadiene-styrene copolymers; cellulose triacetate; polycarbonate; urethane resins such as polyurethane and acrylic-modified polyurethane; polymethylpentene; polysulfone; Polyether ether ketone; polyether sulfone; polyphenylene sulfide; polyimide resin such as polyetherimide and polyimide; polyamide resin; acrylic resin; fluorine resin and the like can be mentioned.
Among these, it is preferable to contain one or more kinds of resins selected from polyester-based resins and polyolefin-based resins.

These resin films may be composed of only one type of resin or may be composed of two or more types of resins.
Further, the resin film may be unstretched or may be stretched in a uniaxial direction or a biaxial direction such as vertical or horizontal.
Further, the resin film may be a resin film having a cavity-containing layer containing a cavity inside. A resin film may be formed in which a resin layer containing no cavities is further laminated on at least one surface side of the cavity-containing layer.
In addition, the resin film may contain various additives such as an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a slip agent, an anti-blocking agent, and a colorant together with these resins.

These base materials may be used alone or in combination of two or more to form a multilayer body.
Examples of the multilayer body used as the base material include a laminated base material obtained by laminating a paper base material with a resin, a resin film with a metal film having a metal film on the surface of the resin film, and the like.

Examples of the laminated base material include laminated paper obtained by laminating the above-mentioned paper base material with a thermoplastic resin such as polyethylene.

The metal film of the resin film with a metal film can be formed of a metal such as aluminum, tin, chromium, or titanium.
As a method of forming a metal film on the surface of a resin film, a method of vapor deposition of these metals by a PVD (physical vapor deposition) method such as vacuum vapor deposition, sputtering, ion plating, or a metal foil made of the above metal is generally used. Examples thereof include a method of attaching using a specific adhesive.

When the base material used in one embodiment of the present invention is a resin film or a laminated base material, the surface of these base materials is subjected to an oxidation method and unevenness from the viewpoint of improving the adhesion to the pressure-sensitive adhesive layer. One or more treatments selected from surface treatments such as chemical conversion methods and primer treatments may be performed.
The oxidation method is not particularly limited, and examples thereof include a corona discharge treatment method, a plasma treatment method, chromium acid oxidation (wet), a flame treatment, a hot air treatment, and an ozone / ultraviolet irradiation treatment.
The unevenness method is not particularly limited, and examples thereof include a sandblast method and a solvent treatment method.

As the base material used in one aspect of the present invention, a resin film and a laminated base material are preferable from the viewpoint of preventing breakage of the pressure-sensitive adhesive sheet during use and preventing wrinkles, and various cables and a laminated base material are preferable. From the viewpoint of improving the wrapping property around the cord, a resin film is more preferable, and a resin film containing one or more resins selected from polyester resins and polyolefin resins is more preferable, and polyester resins and polyolefin resins are more preferable. A resin film containing one or more kinds of resins selected from the above and having a cavity-containing layer is more preferable.

The rigidity of the base material used in one aspect of the present invention is preferably 0.10 to 0.45 mN, more preferably 0.10 to 0.45 mN, from the viewpoint of forming an adhesive sheet that is easy to bend and has excellent shape retention during use. It is 0.14 to 0.28 mN, more preferably 0.18 to 0.24 mN.
From the same viewpoint, the tear strength of the base material used in one aspect of the present invention is preferably 100 to 1000 mN, more preferably 200 to 500 mN, and even more preferably 250 to 350 mN.
In this specification, the rigidity and softness of the base material and the tear strength mean the values measured based on the method described in Examples.
In addition, the rigidity and tear strength of the base material are obtained by measuring along at least one of the flow direction (MD direction) at the time of molding the base material and the direction perpendicular to the MD direction (TD direction). It suffices if the value belongs to the above range.
When it is difficult to specify the MD direction and the TD direction of the base material, if the base material is rectangular, the rigidity or the tear strength can be increased along either the vertical direction or the horizontal direction of the base material. It suffices if it belongs to the above range.

The thickness of the base material is preferably 10 to 500 μm, more preferably 15 to 300 μm, still more preferably 20 to 200 μm, and even more preferably 25 to 100 μm.

<Adhesive layer>
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention is a layer formed from a pressure-sensitive adhesive composition containing a styrene resin (A) and a pressure-sensitive adhesive resin (B).
The styrene-based resin (A) contains a styrene-isopregen block copolymer (SI) and a styrene-isoprene-styrene triblock copolymer (SIS), and the styrene-isoprene-styrene triblock copolymer (SIS). The content of SIS) is 35% by mass or more based on the total amount of the styrene resin (A).
The tackifier resin (B) contains one or more selected from a rosin-based resin and a non-hydrogenated terpene-based resin having no aromatic structure.
The mass ratio [(B) / (A)] of the tackifier resin (B) and the styrene resin (A) is 1.0 or less.
The mass ratio [(B) / (SIS)] of the tackifier resin (B) and the styrene-isoprene-styrene triblock copolymer (SIS) in the styrene resin (A) is less than 2.5. Is.
By forming the pressure-sensitive adhesive layer from the pressure-sensitive adhesive composition satisfying the above requirements, a pressure-sensitive adhesive layer in which a decrease in adhesive strength with time is suppressed is obtained.

The thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet according to one aspect of the present invention is preferably 10 to 150 μm, more preferably 15 to 120 μm, still more preferably 18 to 90 μm, and even more preferably 20 to 60 μm.

The pressure-sensitive adhesive composition, which is a material for forming the pressure-sensitive adhesive layer, is used for other resin components and the pressure-sensitive adhesive described later, together with the styrene resin (A) and the pressure-imparting resin (B), as long as the effects of the present invention are not impaired. Additives may be included.
However, in one aspect of the present invention, the total content of the styrene resin (A) and the tackifier resin (B) is preferably 90 to 90 to the total amount (100% by mass) of the active ingredient of the pressure-sensitive adhesive composition. It is 100% by mass, more preferably 92 to 100% by mass, still more preferably 95 to 100% by mass, and even more preferably 98 to 100% by mass.
In the present specification, the "active ingredient of the pressure-sensitive adhesive composition" refers to a component contained in the pressure-sensitive adhesive composition excluding a solvent such as water or an organic solvent.

<Styrene resin (A)>
The pressure-sensitive adhesive composition used in the present invention contains a styrene resin (A).
The styrene resin (A) is also referred to as a styrene-isopregen block copolymer (SI) (hereinafter, also referred to as “SI resin”) and a styrene-isoprene-styrene triblock copolymer (SIS) (hereinafter, also referred to as “SIS resin”). The content of the SIS resin is 35% by mass or more based on the total amount of the styrene resin (A).
When the content of the SIS resin is less than 35% by mass based on the total amount of the styrene resin (A), the motility of the isoprene domain increases and the tackifying resin (B) bleeds out over time. , The adhesive strength of the pressure-sensitive adhesive layer may decrease over time.
From the viewpoint of suppressing the bleed-out of the tackifier resin (B) over time, the content of the SIS resin is preferably 38% by mass, more preferably 40% by mass, based on the total amount of the styrene resin (A). It is preferably 41% by mass or more, more preferably 42% by mass or more, and even more preferably 43% by mass or more.
Further, from the viewpoint of making it easier to increase the adhesive force of the pressure-sensitive adhesive layer by making the balance between the cohesive force and the wettability of the styrene resin (A) good, the content of the SIS resin is the styrene resin (A). It is preferably 60% by mass or less, more preferably 57% by mass or less, and further preferably 55% by mass or less based on the total amount of the above.

In one aspect of the present invention, the total content of the SI resin and the SIS resin in the styrene resin (A) is preferably 90 to 100% by mass, more preferably 92 to 90% based on the total amount of the styrene resin (A). It is 100% by mass, more preferably 95 to 100% by mass, still more preferably 98 to 100% by mass, and even more preferably 100% by mass.

Further, in one aspect of the present invention, the content of the structural unit (AS) derived from styrene is the total amount of the structural unit (A) of the styrene resin (A) from the viewpoint of facilitating the effect of the present invention. 100% by mass), preferably less than 25% by mass, more preferably 5 to 24% by mass, still more preferably 8 to 20% by mass, even more preferably 10 to 20% by mass, still more preferably 12 to 18% by mass. %, More preferably 13 to 16% by mass.

Further, in one aspect of the present invention, the content of the structural unit (AI) derived from isoprene is the total amount of the structural unit (A) of the styrene resin (A) from the viewpoint of facilitating the effect of the present invention. 100% by mass), preferably more than 75% by mass, more preferably 76 to 95% by mass, still more preferably 80 to 92% by mass, still more preferably 80 to 90% by mass, still more preferably 82 to 88% by mass. %, More preferably 84 to 87% by mass.

The mass average molecular weight (Mw) of the styrene resin (A) is preferably 100,000 to 500,000, more preferably 150,000 to 450,000, and even more preferably 200,000 to 400,000.
In the present specification, the "mass average molecular weight (Mw)" is a standard polystyrene-equivalent value measured by a gel permeation chromatography (GPC) method, and is specifically based on the method described in Examples. It is a value measured by.

<Adhesive resin other than styrene resin (A)>
The pressure-sensitive adhesive composition used in one aspect of the present invention may contain a pressure-sensitive adhesive resin having a mass average molecular weight (Mw) of 10,000 or more other than the styrene resin (A) as long as the effects of the present invention are not impaired. However, from the viewpoint of making it easier to exert the effect of the present invention, the smaller the content of the adhesive resin is, the more preferable it is.

The content of the adhesive resin other than the styrene resin (A) is preferably 0 to 10 parts by mass, more preferably 0 to 10 parts by mass, based on 100 parts by mass of the total amount of the styrene resin (A) contained in the pressure-sensitive adhesive composition. Is 0 to 5 parts by mass, more preferably 0 to 1 part by mass, still more preferably 0 to 0.01 part by mass, and even more preferably no adhesive resin other than the styrene resin (A) is contained. Is.

Examples of such an adhesive resin include one or more selected from styrene resins other than the styrene resin (A), acrylic resins, urethane resins, polyisobutylene resins and the like.

<Adhesive-imparting resin (B)>
The pressure-sensitive adhesive composition used in the present invention contains one or more types of pressure-imparting resin (B) selected from a rosin-based resin and a non-hydrogenated terpene-based resin having no aromatic structure.
In the present invention, the adhesive strength of the pressure-sensitive adhesive layer can be improved by containing the above-mentioned styrene resin (A) in combination with the specific pressure-sensitive adhesive resin (B).

In the present specification, the tackifier resin (B) is a component that supplementarily improves the adhesive strength of the tacky resin, and is an oligomer having a mass average molecular weight (Mw) of usually less than 10,000. It is distinguished from the adhesive resin of.

The non-hydrogenated terpene resin having no aromatic structure, which can be selected as the tackifier resin (B), has a structural unit derived from isoprene, is not hydrogenated, and is subjected to phenol modification and aromatic modification. Any resin that has not been used may be used. The non-hydrogenated terpene resin having no aromatic structure is clearly distinguished from the terpene resin having an aromatic structure, such as an aromatic-modified terpene resin and a terpene phenol resin.

Examples of the non-hydrogenated terpene resin having no aromatic structure include terpene resins and the like.

Examples of the rosin-based resin that can be selected as the tackifier resin (B) include rosin resin, rosin phenol resin, rosin ester, and stabilized rosin ester, and stabilized rosin ester is preferable. The stabilized rosin ester is a rosin-based resin obtained by esterifying stabilized rosin that has been subjected to one or more treatments selected from disproportionation, dimerization, hydrogenation, and the like. The rosin-based resin may be a hydrogenated rosin-based resin in which the above compound is hydrogenated.

In one aspect of the present invention, the tackifier resin (B) includes a non-hydrogenated terpene resin having no aromatic structure and a stabilized rosin ester from the viewpoint of improving the adhesive strength of the pressure-sensitive adhesive layer. It is preferably one or more selected from the above, and more preferably a non-hydrogenated terpene resin having no aromatic structure.
Among the non-hydrogenated terpene resins having no aromatic structure, the terpene resin is preferable.

The softening point of the tackifier resin (B) is preferably 70 to 140 ° C., more preferably 80 to 135 ° C., and even more preferably 85 to 130 ° C. from the viewpoint of facilitating the good adhesive strength of the pressure-sensitive adhesive layer. , Even more preferably 95 ° C. to 125 ° C., even more preferably 105 to 125 ° C.
In this specification, the softening point of the tackifier resin (B) means a value measured in accordance with JIS K2207: 2006.
When two or more types of tackifier resins (B) are used in combination, the weighted average value calculated from the softening point and the blending amount of each tackifier resin (B) is preferably in the above range.

In one aspect of the present invention, the content of the tackifier resin (B) is 100 parts by mass or less with respect to 100 parts by mass of the total amount of the styrene resin (A) in the pressure-sensitive adhesive composition.
When the content of the tackifier resin (B) is more than 100 parts by mass with respect to 100 parts by mass of the total amount of the styrene resin (A) in the pressure-sensitive adhesive composition, the bleed-out of the tackifier resin (B) occurs. It may occur over time and the adhesive strength of the pressure-sensitive adhesive layer may decrease over time. On the other hand, when the content of the tackifier resin (B) is 100 parts by mass or less with respect to 100 parts by mass of the total amount of the styrene resin (A) in the pressure-sensitive adhesive composition, the styrene resin (A) becomes The tackifier resin (B) is easily compatible with each other, and bleed-out of the tackifier resin (B) over time can be suppressed.
Here, from the viewpoint of making it easier to suppress the occurrence of bleed-out of the tackifier resin (B) over time, the content of the tackifier resin (B) is the styrene resin (A) in the pressure-sensitive adhesive composition. With respect to 100 parts by mass of the total amount, preferably less than 100 parts by mass, more preferably 90 parts by mass or less, still more preferably 85 parts by mass or less, still more preferably 80 parts by mass or less, still more preferably 75 parts by mass or less. is there.
Further, from the viewpoint of making it easy to sufficiently secure the adhesive strength of the pressure-sensitive adhesive layer, the content of the pressure-sensitive adhesive resin (B) is based on 100 parts by mass of the total amount of the styrene-based resin (A) in the pressure-sensitive adhesive composition. It is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, and further preferably 60 parts by mass or more.

<Adhesive-imparting resin other than adhesive-imparting resin (B)>
The pressure-sensitive adhesive composition used in one aspect of the present invention may contain a pressure-imparting resin other than the component (B) as long as the effects of the present invention are not impaired.
Examples of the tackifier resin other than the tackifier resin (B) include aromatic-modified terpene resin, terpene phenol resin, and petroleum resin. Among these, in particular, the aromatic-modified terpene resin and the terpene phenol resin have high compatibility with the styrene domain of the styrene resin (A), so that the cohesive force characteristic of the styrene resin (A) is reduced. It is easy to reduce the adhesive strength of the adhesive layer. Further, according to the study by the present inventors, it has been confirmed that petroleum resins such as hydrogenated petroleum resins also tend to reduce the adhesive strength of the pressure-sensitive adhesive layer. Therefore, from the viewpoint of facilitating the improvement of the adhesive strength of the pressure-sensitive adhesive layer, the content of the pressure-imparting resin other than the pressure-imparting resin (B) is preferably smaller.

The content of the tackifier resin other than the tackifier resin (B) is preferably 0 to 10 parts by mass, more preferably 0 to 10 parts by mass, based on 100 parts by mass of the total amount of the tackifier resin (B) contained in the pressure-sensitive adhesive composition. Is 0 to 5 parts by mass, more preferably 0 to 1 part by mass, and even more preferably 0 to 0.01 part by mass. Even more preferably, it does not contain a tackifier resin other than the tackifier resin (B).

<Mass ratio of adhesive resin (B) and styrene resin (A)>
The mass ratio [(B) / (A)] of the tackifier resin (B) and the styrene resin (A) of the pressure-sensitive adhesive composition used in the present invention is 1.0 or less.
When [(B) / (A)] is larger than 1.0, it becomes difficult to improve the adhesive strength of the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive resin (B) bleeds out over time, resulting in adhesion. The adhesive strength of the agent layer may decrease over time. On the other hand, when [(B) / (A)] is 1.0 or less, the tackifier resin (B) is likely to be compatible with the styrene resin (A), and the tackifier resin (B) with time. Bleedout can be suppressed. In addition, the adhesive strength of the pressure-sensitive adhesive layer can be made excellent.
Here, from the viewpoint of making it easier to suppress the occurrence of bleed-out of the tackifier resin (B) over time, [(B) / (A)] is preferably less than 1.0, more preferably 0. It is 90 or less, more preferably 0.85 or less, even more preferably 0.80 or less, and even more preferably 0.75 or less.
Further, from the viewpoint of making it easy to sufficiently secure the adhesive strength of the pressure-sensitive adhesive layer, [(B) / (A)] is preferably 0.50 or more, more preferably 0.55 or more, still more preferably 0.60. That is all.

<Mass ratio of adhesive resin (B) and isoprene-derived structural unit (AI)>
The mass ratio [(B) / (AI)] of the pressure-sensitive adhesive resin (B) and the isoprene-derived structural unit (AI) of the pressure-sensitive adhesive composition used in the present invention is 1.2 or less. Is preferable. [(B) / (AI)] is an index indicating the content of the tackifier resin (B) with respect to the isoprene domain in the styrene resin (A), and when it is 1.2 or less, the tackifier is imparted. It can be said that the resin (B) is easily compatible with the isoprene domain, and the bleed-out of the tackifier resin (B) over time is also easily suppressed. In addition, it is easy to sufficiently secure the adhesive strength of the pressure-sensitive adhesive layer.
From this point of view, [(B) / (AI)] is preferably 1.1 or less, more preferably 1.05 or less, still more preferably 1.0 or less.
Further, from the viewpoint of making it easy to sufficiently secure the adhesive strength of the pressure-sensitive adhesive layer, [(B) / (AI)] is preferably 0.60 or more, more preferably 0.65 or more, still more preferably 0. .70 or more.

<Mass ratio of adhesive resin (B) and styrene-isoprene-styrene triblock copolymer (SIS)>
The mass ratio [(B) / (SIS)] of the pressure-sensitive adhesive resin (B) and the styrene-isoprene-styrene triblock copolymer (SIS) of the pressure-sensitive adhesive composition used in the present invention is less than 2.5. is there.
When [(B) / (SIS)] is 2.5 or more, the adhesive strength of the pressure-sensitive adhesive layer cannot be sufficiently secured. Moreover, the tackifier resin (B) bleeds out over time. [(B) / (SIS)] is a parameter that defines the content of the tackifier resin (B) with respect to the content of the SIS resin that controls the motility of the isoprene domain, and the movement of the isoprene domain. It can be said that the relationship between the suppression of the sex and the content of the tackifier resin (B) is defined. The smaller [(B) / (SIS)], the more easily the binding force caused by the SIS resin acts, the more the motility of the isoprene domain is suppressed, and the more difficult it is for the tackifier resin (B) to bleed out. It can be said that. On the contrary, the larger [(B) / (SIS)], the more difficult the binding force due to the SIS resin acts, the higher the motility of the isoprene domain, and the easier it is for the tackifying resin (B) to bleed out. It can be said that there is.
Here, [(B) / (SIS)] is preferable from the viewpoint of making it easy to sufficiently secure the adhesive strength of the pressure-sensitive adhesive layer and easily suppressing the bleed-out of the pressure-sensitive adhesive resin (B) over time. Is 2.4 or less, more preferably 2.35 or less, still more preferably 2.3 or less.
Further, from the viewpoint of making it easy to sufficiently secure the adhesive strength of the pressure-sensitive adhesive layer, [(B) / (SIS)] is preferably 1.2 or more, more preferably 1.3 or more, still more preferably 1.4. That is all.

<Additives for adhesives>
The pressure-sensitive adhesive composition used in one aspect of the present invention may contain a more general additive for a pressure-sensitive adhesive as long as the effects of the present invention are not impaired.
Examples of such adhesive additives include cross-linking agents, ultraviolet absorbers, antioxidants, rust inhibitors, antibacterial materials, insect repellents, fragrances, pigments, dyes, curing agents, curing aids, catalysts and the like. Can be mentioned.
These may be used individually by 1 type, and may be used in combination of 2 or more type.

In the pressure-sensitive adhesive composition used in one aspect of the present invention, it is preferable that the content of the plasticizer is small from the viewpoint of suppressing a decrease in the adhesive strength of the pressure-sensitive adhesive layer with time. When the plasticizer is contained in the pressure-sensitive adhesive layer, it becomes a bleed product, which may cause a decrease in the adhesive strength of the pressure-sensitive adhesive layer over time.
Examples of such a plasticizer include liquid paraffin and the like.

The specific content of the plasticizer is preferably 0 to 5 parts by mass with respect to 100 parts by mass in total of the styrene resin (A) and the tackifier resin (B) contained in the pressure-sensitive adhesive composition. It preferably contains 0 to 1 part by mass, more preferably 0 to 0.1 part by mass, and even more preferably no plasticizer.

Further, in the pressure-sensitive adhesive composition used in one aspect of the present invention, the smaller the content of the filler, the more preferable, from the viewpoint of facilitating the improvement of the adhesive strength of the pressure-sensitive adhesive layer.
Examples of the filler include conductive fillers, metal oxides, silica and the like.
The specific content of the filler is preferably 0 to 5 parts by mass with respect to 100 parts by mass in total of the styrene resin (A) and the tackifier resin (B) contained in the pressure-sensitive adhesive composition. It preferably contains 0 to 1 parts by mass, more preferably 0 to 0.1 parts by mass, and even more preferably no filler.

<Peeling liner>
As the release liner of the pressure-sensitive adhesive sheet of one aspect of the present invention, a release liner that has been subjected to double-sided release treatment, a release liner that has been subjected to single-sided release treatment, or the like is used, and a release agent is applied on the base material for the release liner. And so on.
Examples of the base material for the release liner include paper base materials such as glassin paper and high-quality paper, laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper base materials, polyethylene terephthalate resin, polybutylene terephthalate resin, and polyethylene. Examples thereof include polyester resin films such as naphthalate resin, plastic films such as polyolefin resin films such as polypropylene resin and polyethylene resin, and the like.
Examples of the release agent include silicone-based resins, olefin-based resins, long-chain alkyl-based resins, alkyd-based resins, fluororesins, and the like.

The thickness of the release liner is appropriately set, but is preferably 10 to 200 μm, more preferably 25 to 150 μm.

<Non-adhesive layer>
Like the pressure-sensitive adhesive sheet 4 shown in FIG. 4, the pressure-sensitive adhesive sheet according to one aspect of the present invention may have a non-adhesive layer as a part of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer.
The constituent material of the non-adhesive layer is appropriately selected depending on the intended use. For example, various paper materials also used as the above-mentioned base material; a metal film containing aluminum, copper, silver, gold, etc.; an acrylic resin. , Acrylic urethane resin, polyurethane resin, butyral resin, nitrocellulose resin, acetylcellulose resin, polyester resin, vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, etc. Examples thereof include a resin film containing a non-adhesive resin.

When the non-adhesive layer is composed of a resin film, the resin film is formed by using an ink containing a colorant such as a pigment or a dye, a filler, a solvent, or the like together with the above-mentioned non-adhesive resin. It may be the one that has been used.

The pigment may be either an inorganic pigment or an organic pigment.
Examples of the inorganic pigment include carbon black and metal oxides.
Examples of the organic pigment include azo pigment, diazo pigment, phthalocyanine pigment, quinacridone pigment, isoindolinone pigment, dioxazine pigment, perylene pigment, perinone pigment, thioindigo pigment, anthraquinone pigment, quinophthalone pigment and the like.
Examples of the dye include acid dyes, reactive dyes, direct dyes, oil-soluble dyes, disperse dyes, cationic dyes and the like.

The filler is preferably composed of fine particles, and may be inorganic particles or organic particles.
The average particle size of the fine particles is usually 0.01 to 100 μm.

Examples of the inorganic particles used as a filler include metals, metal oxides (silica, alumina, boehmite, titanium oxide, etc.), minerals (montmorillonite, biderite, hectolite, saponite, stibunchite, nontronite, saconite, etc.). Smectite, bentonite, etc.), calcium carbonate, magnesium carbonate, calcium sulfate, barium sulfate, aluminum hydroxide, aluminum silicate, calcium silicate, magnesium silicate and the like.
Examples of the organic particles used as the filler include acrylic beads and the like.

The thickness of the non-adhesive layer is preferably 0.05 to 16 μm, more preferably 0.1 to 12 μm, and even more preferably 0.5 to 8 μm.

The method for forming the non-adhesive layer can be appropriately selected depending on the constituent materials of the non-adhesive layer.
For example, when the non-adhesive layer is composed of a paper material, the paper material can be laminated on the adhesive surface of the pressure-sensitive adhesive layer.
When the non-adhesive layer is composed of a metal film, it is preferably formed by vapor deposition on the adhesive surface of the pressure-sensitive adhesive layer.

When the non-adhesive layer is composed of a resin film, a resin composition containing a non-adhesive resin is applied onto the adhesive surface of the adhesive layer to form a coating film, and the coating film is dried to form the coating film. can do.
At this time, the resin composition may be in the form of a solution by adding a diluting solvent.
Further, as a coating method, a known method can be applied, but it may be performed by printing such as gravure printing, screen printing, offset printing, flexographic printing and the like.
Further, after forming a resin film on the peeling surface of the peeling liner by the above method, the resin film and the adhesive surface of the pressure-sensitive adhesive layer can be bonded to each other.

<Manufacturing method of adhesive sheet>
The method for producing the pressure-sensitive adhesive sheet of the present invention is not particularly limited and may be appropriately selected depending on the structure of the pressure-sensitive adhesive sheet.
As a method for forming the pressure-sensitive adhesive layer, the above-mentioned pressure-sensitive adhesive composition is applied on the peeling-treated surface of the base material or the peeling liner to form a coating film, and the coating film is dried to form the pressure-sensitive adhesive layer. It is preferable to do so.
In order to improve the workability of coating the base material or the release liner on the release surface, it is preferable that the pressure-sensitive adhesive composition is further diluted with a diluting solvent to form a solution.

Examples of the diluting solvent include water and organic solvents such as methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexane, n-hexane, toluene, xylene, n-propanol, and isopropanol.
The solid content concentration of the solution of the pressure-sensitive adhesive composition is preferably 5 to 70% by mass, more preferably 10 to 65% by mass, and further preferably 15 to 60% by mass.

Examples of the method for applying the solution of the pressure-sensitive adhesive composition include a spin coating method, a spray coating method, a bar coating method, a knife coating method, a roll coating method, a blade coating method, and a die coating method.
Further, as the coating method, printing such as gravure printing, screen printing, offset printing, flexographic printing or the like may be performed.

As a specific manufacturing method, the pressure-sensitive adhesive sheet of the first aspect of the present invention shown in FIG. 1 and the pressure-sensitive adhesive sheet of the second aspect of the present invention shown in FIG. 2 include, for example, a base material. A step of applying a solution of the adhesive composition on a predetermined surface of 10 to form a coating film, and drying the coating film to form a first pressure-sensitive adhesive layer 21 and a second pressure-sensitive adhesive layer 22. The manufacturing method to have is mentioned.
The first pressure-sensitive adhesive layer 21 and the second pressure-sensitive adhesive layer 22 are preferably formed at the same time, but may be formed separately.

Further, as another method for producing the pressure-sensitive adhesive sheet according to the first and second aspects of the present invention, a pressure-sensitive adhesive is used in the same manner as described above by using a solution of the pressure-sensitive adhesive composition on the peel-processed surface of the peel-off liner. After forming the layer, the laminate consisting of the release liner and the pressure-sensitive adhesive layer is cut to a predetermined size, and the adhesive surface of the pressure-sensitive adhesive layer of the cut laminate is bonded to a predetermined position on the base material to produce the product. There is also a method.

As a method for producing the pressure-sensitive adhesive sheet according to the third aspect of the present invention shown in FIG. 3, for example, a solution of the pressure-sensitive adhesive composition is used on the surface of either the base material or the release liner in the same manner as described above. Then, a manufacturing method including a step of forming a pressure-sensitive adhesive layer and laminating the other release liner or a base material on the pressure-sensitive adhesive layer to obtain a laminated body can be mentioned.
The release liner used in the above step may be provided with a notch in advance.
Further, when a release liner having no cut portion is used, after obtaining the laminated body in the above step, the cut portion is cut at a predetermined position from the release liner side of the laminate in the thickness direction. Can be provided.

As a method for producing the pressure-sensitive adhesive sheet according to the fourth aspect of the present invention shown in FIG. 4, for example, a solution of the pressure-sensitive adhesive composition is used on the surface of the base material, and the pressure-sensitive adhesive layer is formed in the same manner as described above. Examples thereof include a manufacturing method having a step of forming and forming a non-adhesive layer at a predetermined position on the adhesive surface of the pressure-sensitive adhesive layer.
Examples of the method for forming the non-adhesive layer include the above-mentioned methods, which are appropriately selected depending on the constituent materials of the non-adhesive layer.
After forming the non-adhesive layer, a release liner may be further laminated on the exposed adhesive surface of the adhesive layer and the surface of the non-adhesive layer.

<Use of adhesive sheet>
The adhesive sheet of the present invention has an adhesive layer that is excellent in adhesive strength and suppresses a decrease in adhesive strength with time, and is suitably used as an adhesive tape for binding, a display label (identification label), a tag, or the like. Can be done.
Therefore, it is preferable that the adhesive sheet of the present invention is used as a binding adhesive tape for binding various articles, an identification label by wrapping it around various cables and cords, a tag, and the like. More specifically, it is preferable to wrap it around a cable and a cord in a vehicle and use it as an identification label or a tag in an automobile manufacturing factory or the like.

The present invention will be specifically described with reference to the following examples, but the present invention is not limited to the following examples.

[Measurement method of various physical property values]
The methods for measuring various physical property values in this embodiment are as described below.

(1) Mass average molecular weight (Mw)
It was measured under the following conditions using a gel permeation chromatograph device (manufactured by Tosoh Corporation, product name "HLC-8020"), and measured in terms of standard polystyrene.
(Measurement condition)
-Column: "TSK guard volume HXL-H", "TSK gel GMHXL" (2 pieces), and "TSK gel G2000HXL" (all manufactured by Tosoh Corporation) are connected in sequence.-Column temperature: 40 ° C.
-Development solvent: tetrahydrofuran-Flow velocity: 1.0 mL / min

(2) Softening point Measured according to the ring-and-ball method based on JIS K2207: 2006.

(3) Rigidity and Softness of Base Material The base material used in Examples and Comparative Examples was cut into a rectangle having a length of 38 mm and a width of 25 mm and used as a measurement sample.
For the measurement sample, use a rigidity tester (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Gare type flexibility tester") in an environment of 23 ° C and 50% RH (relative humidity), JIS. According to the Gale method of L 1096 (2010) 8.22.1, the base material is rigid and soft in the flow direction (MD direction) during molding of the base material and the direction perpendicular to the MD direction (TD direction). The degrees were measured respectively.

(4) Tear Strength of Base Material The base material used in Examples and Comparative Examples was cut into a rectangle having a length of 75 mm and a width of 63 mm and used as a measurement sample.
Four of the measurement samples are stacked, and using an Elmendorf tear tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.) in an environment of 23 ° C. and 50% RH (relative humidity), according to JIS K 7128-2 (1998). , The tear test was performed four times in each of the MD direction and the TD direction of the base material. Then, the average value (tear strength of four base materials) of each of the four values measured in the MD direction and the TD direction is calculated, and the value of 1/4 of the average value is used as the tear strength of the base material. I made it.

(5) Thickness of Adhesive Layer A constant pressure thickness measuring device (manufactured by Teclock Co., Ltd., product name "PG-02J") was used, and measurement was performed in accordance with JIS K6783, Z1702, and Z1709.

[Examples 1 to 14, Comparative Examples 1 to 7]
Each component of the type and blending amount (solid content ratio) shown in Table 1 was added, further diluted with toluene, and stirred to prepare a solution of a pressure-sensitive adhesive composition having a solid content concentration of 50% by mass.
Then, a solution of the prepared pressure-sensitive adhesive composition is applied to two regions from both ends of the peeling liner to 100 mm on the peeling-treated surface of the peeling liner having a width of 300 mm to form a coating film, and the two coating films are formed. Was dried at 100 ° C. for 1 minute to form an adhesive layer having a thickness of 55 μm.
Next, a polyester film (1) having a cavity-containing layer, which is a base material (manufactured by Toyobo Co., Ltd., product name "Crisper K2411", thickness 50 μm, rigidity: MD direction = 0.25 mN, TD direction = 0 .28 mN, tear strength: MD direction = 319 mN, TD direction = 294 mN) and the adhesive surfaces of the two formed adhesive layers are bonded together to form the same configuration as the adhesive sheet 1A shown in FIG. 1 (a). An adhesive sheet to have was prepared.

Details of each component shown in Table 1 used in the preparation of the pressure-sensitive adhesive composition are as follows.
<Styrene resin (A)>
-Styrene-based resin (1): SIS resin (triblock body) / SI resin (diblock body) = 74/26 (mass%) mixed resin, styrene content = 14% by mass, Mw = 207,000.
-Styrene-based resin (2): SIS resin (triblock body) / SI resin (diblock body) = 22/78 (mass%) mixed resin, styrene content = 15% by mass, Mw = 354,000.

<Adhesive-imparting resin (B)>
B1: Non-hydrogenated terpene resin having no aromatic structure (manufactured by Yasuhara Chemical Co., Ltd., product name "YS resin PX1150N", terpene resin, softening point = 115 ° C.)
B2: Rosin resin (manufactured by Harima Chemicals, Inc., product name "Haritac F105", stabilized rosin ester, softening point = 105 ° C)
-B3: Hydrogenated petroleum resin (manufactured by Arakawa Chemical Industry Co., Ltd., product name "Arcon P-115", softening point = 115 ° C)
-B4: Aromatic modified terpene resin (manufactured by Yasuhara Chemical Co., Ltd., product name "YS resin TO105", softening point = 105 ° C.)
-B5: Terpene phenol resin (manufactured by Yasuhara Chemical Co., Ltd., product name "YS Polystar G125", softening point = 125 ° C)

Using the adhesive sheets prepared in Examples and Comparative Examples, "adhesive strength immediately after sticking between adhesive surfaces" was measured based on the following method. The results are shown in Tables 1 and 2.

<Adhesive strength immediately after sticking between adhesive surfaces (before sheet promotion)>
A test in which the adhesive coated portion / non-adhesive coated portion / adhesive coated portion of the adhesive sheet is cut into a size of 25 mm × 300 mm so as to be included in this order by 100 mm, and the base material / adhesive layer / release liner is laminated. Pieces were made. The release liner was removed, and the surfaces of the exposed pressure-sensitive adhesive layers were bonded to each other.
After bonding, the center of the non-adhesive portion (the portion 50 mm from both sides of the unapplied portion 100 mm) was cut with scissors.
Immediately after application, based on JIS Z0237: 2000, the resistance force when both ends of the adhesive sheet are pulled in a T shape from two unapplied parts at a pulling speed of 300 mm / min is applied to the adhesive surfaces immediately after application. Measured as force (before seat promotion).

<Adhesive strength immediately after sticking between adhesive surfaces (after promoting the sheet)>
The test piece was allowed to stand in a high temperature environment of 70 ° C. for 3 days, then the release liner was removed, and the exposed adhesive layers were bonded to each other. The adhesive strength immediately after the adhesive surfaces were attached to each other (after the sheet was promoted) was measured by the same method as "adhesive strength (before sheet promotion)", and the decrease in the adhesive force of the adhesive layer of the adhesive sheet with time was examined.

From Table 1, it can be seen that the adhesive sheets produced in Examples 1 to 14 satisfying the requirements of the present invention have excellent adhesive strength immediately after the adhesive surfaces are attached to each other both before and after the sheet is promoted. Further, from this result, the pressure-sensitive adhesive sheets produced in Examples 1 to 14 have good adhesive strength of the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layers are bonded to each other until the pressure-sensitive adhesive layer is adhered to the adherend. It can also be seen that the decrease in the adhesive strength of the pressure-sensitive adhesive layer with time is suppressed until the process is completed.
On the other hand, from Table 2, the adhesive sheets produced in Comparative Examples 1 to 7, which do not satisfy a part of the requirements of the present invention, have adhesive surfaces of each other for either one or both before and after sheet promotion. It can be seen that the adhesive strength immediately after pasting is inferior.
Specifically, it can be seen that the adhesive sheet produced in Comparative Example 1 is inferior in adhesive strength after sheet promotion. Further, it can be seen that the adhesive sheets produced in Comparative Examples 2 to 7 have low adhesive force before sheet promotion, and the adhesive force after sheet promotion is equal to or inferior to that before sheet promotion.
From these results, in the pressure-sensitive adhesive sheet produced in Comparative Example 1, the adhesive strength of the pressure-sensitive adhesive layer over time until the pressure-sensitive adhesive layer was attached to the adherend or until the pressure-sensitive adhesive layers were bonded to each other. It can be seen that it is decreasing. Further, the pressure-sensitive adhesive sheets produced in Comparative Examples 2 to 7 have low adhesive strength of the pressure-sensitive adhesive layer, and during the period until the pressure-sensitive adhesive layer is attached to the adherend or until the pressure-sensitive adhesive layers are bonded to each other. It can be seen that the adhesive strength may decrease over time.

1A, 1B, 2A, 2B, 3, 4 Adhesive sheet 10 Base material 10a, 10b Surface 20 Adhesive layers 201a, 202a Adhesive surface 21 First adhesive layer 22 Second adhesive layers 21a, 22a Adhesive surfaces 30, 31, 32 Peeling liner 301, 302 Peeling liner end 40 Non-adhesive layer X1, X2 Notch

Claims (9)

An adhesive sheet having a base material and an adhesive layer.
The pressure-sensitive adhesive layer is a layer formed from a pressure-sensitive adhesive composition containing a styrene resin (A) and a pressure-sensitive adhesive resin (B).
The styrene-based resin (A) contains a styrene-isopregen block copolymer (SI) and a styrene-isoprene-styrene triblock copolymer (SIS), and the styrene-isoprene-styrene triblock copolymer (SIS). The content of SIS) is 35% by mass or more based on the total amount of the styrene resin (A).
The tackifier resin (B) contains one or more selected from a rosin-based resin and a non-hydrogenated terpene-based resin having no aromatic structure.
The mass ratio [(B) / (A)] of the tackifier resin (B) and the styrene resin (A) is 1.0 or less.
The mass ratio [(B) / (SIS)] of the tackifier resin (B) and the styrene-isoprene-styrene triblock copolymer (SIS) in the styrene resin (A) is less than 2.5. Is an adhesive sheet. The pressure-sensitive adhesive sheet according to claim 1, wherein the mass ratio [(B) / (A)] of the pressure-sensitive adhesive resin (B) and the styrene-based resin (A) is less than 1.0. The mass ratio [(B) / (AI)] of the tackifier resin (B) and the isoprene-derived structural unit (AI) in the styrene resin (A) is 1.2 or less. , The adhesive sheet according to claim 1 or 2. Any of claims 1 to 3, wherein the content of the styrene-derived structural unit (AS) in the styrene resin (A) is less than 25% by mass based on the total amount of the styrene resin (A). The adhesive sheet according to item 1. The pressure-sensitive adhesive sheet according to any one of claims 1 to 4, which is used by adhering the pressure-sensitive adhesive surfaces of the pressure-sensitive adhesive layer to each other. The pressure-sensitive adhesive sheet according to any one of claims 1 to 5, which has a structure in which the pressure-sensitive adhesive layer is laminated on a part of the surface of the base material. The pressure-sensitive adhesive sheet according to claim 6, wherein the pressure-sensitive adhesive layer laminated on a part of the surface of the base material is present at two or more places. The pressure-sensitive adhesive sheet according to claim 6, wherein a part of the pressure-sensitive adhesive surface of the pressure-sensitive adhesive layer is exposed at two or more places, or can be displayed at two or more places. The adhesive sheet according to any one of claims 1 to 8, which is wrapped around an object and used as an identification label or a tag.

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