JP2011016860A - Sheet-shaped adhesive composition, and adhesive sheet having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet-shaped adhesive composition which is excellent in extensibility and is easily manufactured; and to provide an adhesive sheet having it.SOLUTION: The sheet-shaped adhesive composition containing a styrene-ethylene-butylene-styrene block copolymer, includes a sea-island structure, in which the ratio of longer diameter/shorter diameter is 1.5 or more in part or the whole of the island structure in the sea-island structure; most or the whole of the island structure with a ratio of longer diameter/shorter diameter, of 1.5 or more, is arranged in one direction; and, when observed from a direction that is vertical to the arrangement direction and parallel to the principal surface of the sheet-shaped adhesive composition, the total area of the island structure of which the ratio of longer diameter/shorter diameter is 1.5 or more is 70% or more based on the total area of the whole island structure.

Description

  The present invention relates to a sheet-like pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet having the same.

In order to protect various articles and members, a surface protective sheet is often temporarily attached to the surfaces of the articles and members. For example, on the surface of various adherends such as synthetic resin plates, optical members, metal plates, decorative plywood, painted steel plates, painted resin plates or various nameplates, especially the surfaces of diffusion sheets and prism sheets, these surfaces during processing and transportation In order to prevent adhesion of dirt and scratches on the surface, surface protection sheets are frequently used.

This type of surface protective sheet is usually a pressure-sensitive adhesive sheet having a structure in which a pressure-sensitive adhesive layer is laminated on one side of a thermoplastic substrate.
Such a surface protection sheet is affixed to the adherend surface using the adhesive force of the pressure-sensitive adhesive layer, and protects the adherend surface. When the adherend is used, the surface protective sheet is peeled off from the adherend surface. Therefore, the surface protective sheet has suitable adhesiveness so that it can be easily temporarily attached to the surface of the adherend, and has good peelability that can be easily peeled off from the adherend surface after use. It is required to have. Further, there is a strong demand not to contaminate the adherend surface after peeling with adhesive residue or the like.
Moreover, adhesive sheets, such as a surface protection sheet, are industrially manufactured as a wound body obtained by winding a long sheet into a roll. The pressure-sensitive adhesive sheet made of such a wound body is known to have a large increase in adhesive force over time, but has a small force (unfolding force) required to unwind the wound body during use. That is, it is strongly demanded that the winding body can be easily rewound.

By the way, as a material such as a diffusion sheet, polar polymers such as acrylic resins and polycarbonate resins are frequently used. In addition, these optical sheets are shipped to an optical device manufacturer after a surface protective sheet is attached, but they may be exposed to high temperatures during transportation and storage.
For this reason, particularly for application to optical sheets, the pressure-sensitive adhesive layer constituting the surface protection sheet does not use an acrylic pressure-sensitive adhesive that has a particularly large increase in adhesive strength over time. Adhesives were mainly used. Thus, an attempt has been made to avoid an increase in adhesive force over time and to smoothly peel the surface protective sheet from the surface of the lens portion of the optical sheet.

However, since rubber-based pressure-sensitive adhesives are generally solution-coated types, there are problems such as environmental pollution and energy waste during solvent drying, and the back surface of the commonly used olefin substrate layer (the side on which the pressure-sensitive adhesive layer is laminated) A mold release process for the opposite surface) is also required. Further, the conventional hot-melt type pressure-sensitive adhesive can solve or reduce the former problem, but the back side release treatment cannot be avoided.

Therefore, in order to improve rewinding properties, a surface layer containing a polyolefin resin and a pressure-sensitive adhesive layer containing a thermoplastic elastomer are laminated and formed by a coextrusion method, and then a release layer is formed on the back surface of the surface layer. A surface protective sheet obtained by forming a film by a coating method has been proposed (for example, Patent Document 1).

JP 2003-41216 A

However, in the production of the base material layer as in the method described in Patent Document 1, if the release treatment is performed for the lamination of the release layer, the number of production steps is increased. Therefore, it is desirable that excellent developability can be obtained without a release layer.

An object of the present invention is to provide a sheet-like pressure-sensitive adhesive composition that is excellent in developability and easy to manufacture, and a pressure-sensitive adhesive sheet having the same.

As a result of intensive studies, the inventors of the present invention have a sheet-like pressure-sensitive adhesive composition containing a styrene-ethylene-butylene-styrene block copolymer and having a sea-island structure. As a result, the inventors have found that the above-mentioned problems can be solved, and as a result of further research, the present invention has been completed.
That is, the present invention provides the following [1] to [6] and the like.
[1]
A sheet-like pressure-sensitive adhesive composition containing a styrene-ethylene-butylene-styrene block copolymer,
It has a sea-island structure,
Part or all of the island structure in the sea-island structure has a ratio of major axis / minor axis of 1.5 or more,
Most or all of the island structures having a major axis / minor axis ratio of 1.5 or more are arranged in one direction,
An island structure in which the ratio of major axis / minor axis is 1.5 or more when observed from a direction perpendicular to the arrangement direction and parallel to the main surface of the sheet-like pressure-sensitive adhesive composition The sheet-like pressure-sensitive adhesive composition has a total area of 70% or more with respect to the total area of all island structures.
[2]
The sheet-like pressure-sensitive adhesive composition according to the above [1], wherein the content of the styrene-based monomer unit with respect to the whole sheet-like pressure-sensitive adhesive composition is 25 to 60% by weight.
[3]
Furthermore, the sheet-like adhesive composition according to [1] or [2], further including a styrene end block reinforcing agent.
[4]
Melting a composition containing a styrene-ethylene-butylene-styrene block copolymer;
Any of the above [1] to [3] produced by a production method comprising extruding a molten composition into a sheet and cooling and molding the obtained sheet-like composition The sheet-like pressure-sensitive adhesive composition according to item 1.
[5]
The sheet-like pressure-sensitive adhesive composition according to [4], wherein the cooling is performed under conditions of a cooling temperature of 40 ° C. or more and a cooling rate of 40 ° C./min or less.
[6]
The adhesive sheet which has a sheet-like adhesive composition of any one of said [1]-[5] laminated | stacked on the one side of the base material layer and the said base material layer.

According to the sheet-like pressure-sensitive adhesive composition of the present invention, a pressure-sensitive adhesive sheet having excellent developability and simple production can be obtained.

FIG. 1 is a schematic view showing one embodiment of the sheet-like pressure-sensitive adhesive composition of the present invention. FIG. 2 is an electron micrograph of the sheet-like pressure-sensitive adhesive composition of the present invention (Example 3). FIG. 3 is an electron micrograph of the sheet-like pressure-sensitive adhesive composition (Comparative Example 1).

  Details of the present invention will be described below.

The sheet-like pressure-sensitive adhesive composition of the present invention contains a styrene-ethylene-butylene-styrene block copolymer (hereinafter sometimes referred to as SEBS).
The sheet-like pressure-sensitive adhesive composition of the present invention has a sea-island structure.
The island structure in the sea-island structure of the conventional sheet-like pressure-sensitive adhesive composition containing SEBS is spherical, but part or all of the island structure in the sea-island structure of the sheet-like pressure-sensitive adhesive composition of the present invention is oval or rod-shaped. . Here, “long sphere or rod” means that the ratio of major axis / minor axis is 1.5 or more.
Most or all of the long spherical or rod-like island structures are arranged in one direction.
Here, “almost or all of them are arranged in one direction” means that 60% or more of the long or rod-like island structures are arranged in one direction.
The sheet-like pressure-sensitive adhesive composition of the present invention is a direction perpendicular to the arrangement direction and a direction parallel to the main surface of the sheet-like pressure-sensitive adhesive composition (hereinafter sometimes referred to as X direction).
The direction is shown in FIG. ), The total area of the island structure having a ratio of the major axis / minor axis of 1.5 or more is 70% or more with respect to the total area of all island structures. The area ratio is preferably 75% or more. By making this ratio 70% or more, excellent developability can be obtained.
In FIG. 1, the one aspect | mode of the sheet-like adhesive composition of this invention is shown typically. Sheet-like adhesive composition 1
, The island structure (island phase) 3 exists in the sea phase 2, and most or all of the long spherical or rod-like island structures are arranged in one direction (Y direction).

Specifically, the island structure is observed by the following method.
A part of the sheet-like pressure-sensitive adhesive composition is sliced to a thickness of about 70 nm in a direction perpendicular to the X direction, and observed with an electron microscope (magnification 30000). The observation may be performed in a range sufficient to calculate the area ratio, but usually the area is approximately 520000 nm ² (vertical approximately 720 nm × horizontal approximately 7
20 nm). By this observation, the major axis, minor axis, and area of the island structure are measured, and the ratio of the total area of the island structure having the ratio of major axis / minor axis of 1.5 or more to the total area of all island structures is calculated. .

The content of the styrenic monomer units in the entire sheet-like pressure-sensitive adhesive composition of the present invention (sometimes referred to herein as St content) is preferably 25% by weight or more and less than 60% by weight, and 30% by weight. % Or more and less than 50% by weight is more preferable.
When the content is 25% by weight or more, excellent developability is obtained. On the other hand, when the content is less than 60% by weight, sufficient adhesion to the adherend can be obtained.
The content is related to the ratio of the total area of the island structure in which the ratio of the major axis / minor axis is 1.5 or more. The higher the content rate, the higher the ratio tends to be.
In the present specification, examples of the styrene monomer unit include styrene and α-methylstyrene, p-methylstyrene, p-chlorostyrene, chloromethylstyrene, tert-butylstyrene, p-ethylstyrene, divinylbenzene and the like. It is done.
The styrenic monomer units are primarily contained in SEBS and optionally added styrene endblock reinforcement.
Therefore, the St content of the entire sheet-like pressure-sensitive adhesive composition of the present invention is the content of each of the SEBS and styrene end block reinforcing agent used in the present invention in the sheet-like pressure-sensitive adhesive composition of the present invention, and the respective styrene monomers. It can be adjusted mainly by the content of.

The styrene content of SEBS is preferably 15% by weight or more and less than 50% by weight with respect to 100% by weight of SEBS.

Examples of the styrenic block reinforcing agent that is optionally added to the sheet-like pressure-sensitive adhesive composition of the present invention include styrene and α-methylstyrene, p-methylstyrene, p-chlorostyrene, chloromethylstyrene, tert as monomer units. -What has styrene compounds, such as butyl styrene, p-ethyl styrene, and divinylbenzene, is mentioned. These may be used alone or in combination of two or more. Such a styrenic block reinforcing agent can be obtained by polymerizing these monomers. When the styrenic block reinforcing agent is a copolymer composed of two or more types of monomers, the copolymer may be a block copolymer or a random copolymer. As the styrenic block reinforcing agent, among them, those having a softening point of 100 ° C. or higher are preferable,
What has a softening point of 150 degreeC or more is more preferable. Specifically, trade names “ENDEX 155” (softening point 155 ° C.), “ENDEX 160” (softening point 160 ° C.) manufactured by Eastman Chemical Co., Ltd. are preferably used.
The content of the styrenic block reinforcing agent in the sheet-like pressure-sensitive adhesive composition of the present invention is the “S
The “t content” is set to a desired value, specifically, for example, within a range of 25 wt% or more and less than 60 wt%. Specifically, for example, the content is preferably 0 part by weight or more and less than 25 parts by weight, and more preferably 5 parts by weight or more and less than 20 parts by weight with respect to 100 parts by weight of SEBS.

The sheet-like pressure-sensitive adhesive composition of the present invention may further contain a tackifier as necessary.
The tackifier in the present invention means a material that is compatible with the rubber layer that is ethylene-butylene in SEBS and can control the adhesive force.
Examples include petroleum-based resins such as aliphatic copolymers, aromatic copolymers, aliphatic / aromatic copolymer systems and alicyclic copolymers, coumarone-indene resins, terpenes, and the like. Resin, terpene phenol resin, polymerized rosin resin such as rosin, (alkyl) phenol resin,
Examples thereof include xylene-based resins and hydrogenated products thereof. As the tackifier used in the sheet-like pressure-sensitive adhesive composition of the present invention, those having a softening point of 90 to 140 ° C are preferable. These tackifiers may be used alone or in combination of two or more. In addition,
In order to improve peelability and weather resistance, it is more preferable to use a hydrogenated tackifier. Moreover, you may use the tackifier marketed as a blend with an olefin resin.

The content of the tackifier in the sheet-like pressure-sensitive adhesive composition of the present invention is not particularly limited as long as the effects of the present invention are not impaired. Specifically, for example, 0 to 50 weights with respect to 100 parts by weight of SEBS. Part is preferable, and 10 to 40 parts by weight is more preferable. When the content exceeds 50 parts by weight, glue sticking may occur on the adherend when the surface protective sheet is peeled off from the adherend.

In the adhesive composition, in addition to the tackifier for the purpose of controlling adhesive force, etc., if necessary,
For example, olefin resin, silicone polymer, liquid acrylic copolymer, phosphate ester compound, softener, antioxidant, light stabilizer, ultraviolet absorber, filler, pigment, adhesion progress inhibitor, styrene terminal You may add well-known additives, such as a block reinforcement, suitably.

The softener is usually effective for improving the adhesive strength. Examples of the softener include a low molecular weight diene polymer, polyisobutylene, hydrogenated polyisoprene, hydrogenated polybutadiene, paraffin process oil, naphthene process oil, aromatic process oil,
Those generally used for pressure-sensitive adhesives such as castor oil, tall oil, natural oil, liquid polyisobutylene resin, polybutene, or hydrogenated products thereof can be used without particular limitation. These softeners may be used alone or in combination of two or more. Among the softeners exemplified here, there are those that can also function as the tackifier.

The antioxidant is not particularly limited, and for example, phenolic (monophenolic, bisphenolic, high-molecular phenolic) antioxidants, sulfur antioxidants, phosphorus antioxidants and the like are usually used. Can be mentioned.
Examples of the light stabilizer include hindered amine compounds.
The ultraviolet absorber is not particularly limited, and examples thereof include salicylic acid ultraviolet absorbers, benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, and cyanoacrylate ultraviolet absorbers.
Examples of the antiadhesive agent include fatty acid amide, polyethyleneimine long-chain alkyl graft product, soybean oil-modified alkyd resin (for example, “Araquid 251” manufactured by Arakawa Chemical Co., Ltd.).
Etc.), tall oil-modified alkyd resin (for example, Arakawa Chemical Co., Ltd., trade name “Arachid 6300”)
Etc.).
These additives may be used alone or in combination of two or more.

The sheet-like pressure-sensitive adhesive composition of the present invention may contain a styrene-ethylene-butylene block copolymer (SEB) as long as the effects of the present invention are not hindered. By containing SEB, the sheet-like pressure-sensitive adhesive composition can protect the surface of the adherend having an uneven surface without floating. The amount is preferably 0 part by weight or more and less than 50 parts by weight, and more preferably 10 parts by weight or more and less than 40 parts by weight with respect to 100 parts by weight of SEBS.

The sheet-like pressure-sensitive adhesive composition of the present invention is preferably used by being laminated on one side of the base material layer.
Such a base material layer and the adhesive sheet which has the sheet-like adhesive composition of this invention laminated | stacked on the one side of the said base material layer are also one aspect | mode of this invention.

The base material layer used in the present invention is not particularly limited, for example,
Olefin resins containing α-olefin as a monomer component such as polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, ethylene-vinyl acetate copolymer (EVA);
Polyesters such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT);
Polyvinyl chloride (PVC);
Polyphenylene sulfide (PPS);
Amide resins such as polyamide (nylon), wholly aromatic polyamide (aramid);
Polyetheretherketone (PEEK);
Polyimide;
Polyetherimide;
A base material layer formed from a resin selected from polystyrene; and an acrylic resin can be used.
These resins may be used alone or in combination of two or more.

The thickness of the base material layer can be appropriately adjusted depending on the use of the pressure-sensitive adhesive sheet, and generally 10 to 10%.
It is set to about 100 μm.
The base material layer may contain an additive that can be used for a polyolefin film or the like, if desired. The upper limit of the content of such additives is preferably 20% by weight with respect to the entire base material layer.
Examples of such additives include known light stabilizers such as ultraviolet absorbers, antioxidants, hindered amine light stabilizers, and antistatic agents.

The sheet-like pressure-sensitive adhesive composition of the present invention is preferably, for example, an extrusion method, that is,
Melting a composition containing a styrene-ethylene-butylene-styrene block copolymer;
It can be manufactured by a manufacturing method including extruding the melted composition into a sheet and cooling and molding the obtained sheet-shaped composition.

Extrusion may be performed by a known method such as an inflation method or a T-die method.
By the extrusion, most or all of the island structure having a major axis / minor axis ratio of 1.5 or more is
It arranges in the flow direction (MD: Machine Direction) of a composition.
The cooling is preferably performed at a cooling temperature of 40 ° C. or higher from the viewpoint of setting the total area of the island structure having a ratio of major axis / minor axis of 1.5 or more to 70% or more with respect to the total area of all island structures. And a cooling rate of 40 ° C./min or less, more preferably, a cooling temperature of 80 ° C. or more and a cooling rate of 2 ° C./min or less. It is considered that an island structure having a major axis / minor axis ratio of 1.5 or more is formed in the cooling step.
The sheet-like pressure-sensitive adhesive composition of the present invention, together with the base material layer as described above, is an inflation method,
It is preferable to produce the pressure-sensitive adhesive sheet of the present invention by laminating and integrating by co-extrusion by a known method such as a T-die method.

The pressure-sensitive adhesive sheet of the present invention can be wound around a paper core by a conventional method to form a wound body.
In order to easily rewind the wound body, the developing force is preferably less than 3.5 N / 50 mm, and more preferably less than 2.0 N / 50 mm. With such a deployment force, for example, even when the width of the wound body exceeds 1000 mm, the drawing workability can be ensured.

The pressure-sensitive adhesive sheet of the present invention can be suitably used as a surface protective sheet, particularly as a surface protective sheet for a diffusion sheet or a prism sheet.

Below, this invention is demonstrated in detail based on an Example and a comparative example.
The present invention is not limited to the following examples.

Example 1
Styrene-ethylene-butylene-styrene block (DYNARON89 manufactured by JSR Corporation)
03P) 100 parts by weight of ENDEX as styrene end block reinforcing agent (St reinforcing agent)
15 parts by weight of 155 (Eastman Chemical), 10 parts by weight of an alicyclic saturated hydrocarbon resin having a softening point of 100 ° C. as a tackifier, and 1 part of Irganox 1010 (manufactured by Ciba Specialty Chemicals) as an antioxidant Part, 0.5 part by weight of Tinuvin 326 (manufactured by Ciba Specialty Chemicals) was added as an ultraviolet absorber and kneaded to prepare an adhesive composition.
Polypropylene (J715 manufactured by Prime Polymer Co., Ltd.) forming the base material layer and the pressure-sensitive adhesive composition were melted and coextruded at 200 ° C. by a T-die method, cooling temperature 80 ° C., cooling rate 2 ° C./min. Cooling under conditions, a pressure-sensitive adhesive sheet in which a 35 μm-thick polypropylene base material and a pressure-sensitive adhesive layer having a thickness of 10 μm were laminated and manufactured was obtained, and a wound body wound around a paper core having an inner diameter of 3 inches was obtained. . Table 1 shows the content (St content) of the styrene-based monomer units with respect to the entire sheet-shaped adhesive composition.

(Example 2)
A pressure-sensitive adhesive sheet roll was obtained in the same manner as in Example 1 except for the composition ratio and molding conditions shown in Table 1.

(Example 3)
Styrene-ethylene-butylene-styrene (DYNARON8900P manufactured by JSR) 1
00 parts by weight, 20 parts by weight of ENDEX155 (manufactured by Eastman Chemical Co.) as a styrene end block reinforcing agent (St reinforcing agent), 20 parts by weight of an alicyclic saturated hydrocarbon resin having a softening point of 100 ° C. as a tackifier, 1 part by weight of Irganox 1010 (manufactured by Ciba Specialty Chemicals) as an antioxidant and 0.5 part by weight of Tinuvin 326 (manufactured by Ciba Specialty Chemicals) as an ultraviolet absorber are added and kneaded to prepare a pressure-sensitive adhesive composition. Prepared.
Polypropylene (J715 manufactured by Prime Polymer Co., Ltd.) forming the base material layer and the pressure-sensitive adhesive composition were melted and coextruded at 200 ° C. by a T-die method, cooling temperature 40 ° C., cooling rate 1 ° C./min. Cooling under conditions, a pressure-sensitive adhesive sheet in which a 35 μm-thick polypropylene base material and a pressure-sensitive adhesive layer having a thickness of 10 μm were laminated and manufactured was obtained, and a wound body wound around a paper core having an inner diameter of 3 inches was obtained. . Table 1 shows the content (St content) of the styrene-based monomer units with respect to the entire sheet-shaped adhesive composition.

(Comparative Example 1)
A pressure-sensitive adhesive sheet roll was obtained in the same manner as in Example 3 except for the composition ratio and molding conditions shown in Table 1.

(Comparative Example 2)
A pressure-sensitive adhesive sheet roll was obtained in the same manner as in Example 1 except for the composition ratio and molding conditions shown in Table 1.

(Measurement of long / short diameter ratio of sea-island structure)
After dyeing the adhesive sheet with ruthenium tetroxide, the sheet is sliced to a thickness of about 70 nm using a microtome so as to be parallel to the MD of the sheet. , JEM-1200EX II), area 520
A range of 000 nm ² (length 720 nm × width 720 nm) was photographed at a magnification of about 30000 times.

2 and 3 show electron micrographs of the pressure-sensitive adhesive sheets produced in Example 3 and Comparative Example 1, respectively, taken as described above (the bar in each figure is 100 nm long). Show.) As is clear from these, it can be seen that the island has an island structure (island phase) and a sea-island structure dispersed in the sea phase. The major axis, minor axis, and area are measured from the island structure in the photograph, and the ratio of major axis / minor axis is obtained. The ratio of major axis / minor axis to the total area of all island structures is 1.5 or more. The area ratio was determined.

(Evaluation)
The following items were evaluated for each pressure-sensitive adhesive sheet obtained as described above.
The results are shown in Table 2.
(1) Unfolding force The 50 mm-wide wound bodies of the respective surface protection sheets of Examples and Comparative Examples were measured according to JIS Z0237, and the unwinding speed was measured at a speed of 20 m / min.
The results are shown in Table 2. The case where the deployment force is less than 2.0 N / 50 mm is evaluated as excellent, and 2.0 N /
The case where it is 50 mm or more and less than 3.5 N / 50 mm is evaluated as good, and the deployment force is 3.5 N / 50 mm.
The above cases were evaluated as bad.
-Adhesive strength Each surface protection sheet of an Example and a comparative example was affixed on the flat polycarbonate board. Affixing conditions were as follows: a room temperature of 23 ° C. and a relative humidity of 50%, each using a 2 kg pressure-bonded rubber roller, affixed at a speed of 300 mm / min, left in that state for 30 minutes, and then subjected to JI.
Based on SZ0237, the 180 degree peel strength at 25 mm width was measured at a speed of 300 mm / min. The peel strength measured in this way was defined as the adhesive strength.
The results are shown in Table 2. The case where the adhesive strength was 5 N / 25 mm or more and 6.5 N / 25 mm or less was evaluated as good, and the case where it was less than 5 N / 25 mm or exceeded 6.5 N was evaluated as poor.

As is apparent from the above, the pressure-sensitive adhesive sheet having a sheet-like pressure-sensitive adhesive composition having an oval or rod-like structure / island phase area ratio of 70% or more is obtained by an easy production method and has a small development force.

The sheet-like pressure-sensitive adhesive composition of the present invention can be used as a pressure-sensitive adhesive layer of a pressure-sensitive adhesive sheet that is a surface protective sheet or the like.

1 Sheet-like adhesive composition 2 Sea phase 3 Island structure (island phase)
X Observation direction Y Flow direction (Arrangement direction of island structure)

Claims (6)

A sheet-like pressure-sensitive adhesive composition containing a styrene-ethylene-butylene-styrene block copolymer,
It has a sea-island structure,
Part or all of the island structure in the sea-island structure has a ratio of major axis / minor axis of 1.5 or more,
Most or all of the island structures having a major axis / minor axis ratio of 1.5 or more are arranged in one direction,
An island structure in which the ratio of major axis / minor axis is 1.5 or more when observed from a direction perpendicular to the arrangement direction and parallel to the main surface of the sheet-like pressure-sensitive adhesive composition The sheet-like pressure-sensitive adhesive composition has a total area of 70% or more with respect to the total area of all island structures. 2. The sheet-like pressure-sensitive adhesive composition according to claim 1, wherein the content of the styrene-based monomer unit with respect to the whole sheet-like pressure-sensitive adhesive composition is 25 to 60% by weight. Furthermore, the sheet-like adhesive composition of Claim 1 or 2 containing a styrene terminal block reinforcing agent. Melting a composition containing a styrene-ethylene-butylene-styrene block copolymer;
4. The method according to any one of claims 1 to 3, which is produced by a production method comprising extruding a molten composition into a sheet and cooling and molding the obtained sheet-like composition. Sheet-like adhesive composition. The sheet-like pressure-sensitive adhesive composition according to claim 4, wherein the cooling is performed under conditions of a cooling temperature of 40 ° C or higher and a cooling rate of 40 ° C / min or lower. The adhesive sheet which has a sheet-like adhesive composition of any one of Claims 1-5 laminated | stacked on the one side of the base material layer and the said base material layer.