JP7239128B2 - Adhesive sheet - Google Patents

Description

The present invention relates to an adhesive sheet.

Conventionally, pressure-sensitive adhesive sheets have been widely used for joining various members.
Various adhesives such as acrylic, silicone, rubber, and urethane-based adhesives are used as adhesives forming the adhesive layer of the adhesive sheet.
For example, Patent Document 1 discloses a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer obtained by cross-linking a pressure-sensitive adhesive composition comprising an acrylic polymer composed of predetermined monomers together with acrylic (meth)acrylate. According to Patent Document 1, the adhesive sheet is said to have high adhesive strength even when the thickness of the adhesive layer is reduced to 1 to 20 μm.

Japanese Patent Application Publication No. 2014-118485

By the way, members containing polyolefin resins such as polyethylene and polypropylene are used in various fields.
However, since polyolefin resins have low polarity, even if an ordinary pressure-sensitive adhesive sheet is used to adhere polyolefin resin members, the adhesive force to the members is low and sufficient adhesion cannot be achieved in many cases.
In Patent Document 1, the adhesive force of the adhesive sheet is measured on a glass surface, but the adhesive force on an adherend containing a polyolefin resin is not measured.

Moreover, the surface of the polyolefin-based resin member is rough due to unevenness, surface treatment, or the like, which may hinder adhesion. There is a demand for a PSA sheet that can exhibit excellent adhesive strength even on such rough surfaces.

SUMMARY OF THE INVENTION An object of the present invention is to provide a pressure-sensitive adhesive sheet having excellent adhesion to a polyolefin resin member having a rough surface.

The present inventors have found that a pressure-sensitive adhesive sheet formed from a pressure-sensitive adhesive composition containing a specific styrene-based resin and a tackifying resin and having a pressure-sensitive adhesive layer with a predetermined thickness can solve the above problems. I completed the present invention.

That is, the present invention provides the following [1] to [2].
[1] One or more styrene resins (A) selected from styrene-isoprene diblock copolymers (SI) and styrene-isoprene-styrene triblock copolymers (SIS), and tackifying resins (B) A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing
The pressure-sensitive adhesive layer has a thickness of 15 μm or more,
A pressure-sensitive adhesive sheet having an adhesive force of 8.0 N/25 mm or more to a rough surface of a polypropylene plate having an arithmetic mean roughness Ra of 1.0 to 3.0 μm.
[2] The pressure-sensitive adhesive sheet according to [1] above, wherein the tackifying resin (B) is one or more selected from rosin-based resins, terpene-based resins, styrene-based resins, and hydrocarbon-based resins.

The pressure-sensitive adhesive sheet of the present invention has excellent adhesion to a polyolefin resin member having a rough surface.

BRIEF DESCRIPTION OF THE DRAWINGS It is a cross-sectional schematic diagram of the adhesive sheet which shows an example of a structure of the adhesive sheet of this invention.

As used herein, "mass average molecular weight (Mw)" is a value converted to standard polystyrene measured by a gel permeation chromatography (GPC) method, specifically measured based on the method described in Examples. is the value

[Structure of Adhesive Sheet]
The adhesive sheet of the present invention is not particularly limited as long as it has an adhesive layer.
FIG. 1 is a schematic cross-sectional view of a pressure-sensitive adhesive sheet, showing one example of the structure of the pressure-sensitive adhesive sheet of the present invention.
An example of the adhesive sheet of one embodiment of the present invention is a substrate-attached adhesive sheet 1a having an adhesive layer 12 on at least one surface of a substrate 11, as shown in FIG.
In the structure of the pressure-sensitive adhesive sheet 1a with a substrate, as shown in FIG. 1(b), a pressure-sensitive adhesive sheet 1b with a substrate may be obtained by further laminating a release material 13 on an adhesive layer 12. FIG.

Moreover, as a pressure-sensitive adhesive sheet of one embodiment of the present invention, as shown in FIG. may be The double-sided pressure-sensitive adhesive sheet 1c shown in FIG. 1(c) may have a structure in which a release material is further laminated on the pressure-sensitive adhesive layers 12a and 12b.

Further, as a pressure-sensitive adhesive sheet of one embodiment of the present invention, as shown in FIG. A material-less adhesive sheet 1d may be used.
The release materials 13a and 13b of the substrate-free adhesive sheet 1d may be of the same type of material or may be of different types of materials, but the release material 13a and the release material 13b have different release forces. It is preferable that the material is adjusted to
Examples of the substrate-free pressure-sensitive adhesive sheet include a pressure-sensitive adhesive sheet having a configuration in which a release material having both sides subjected to release treatment and a pressure-sensitive adhesive layer provided on one side thereof is wound into a roll.

The pressure-sensitive adhesive sheets shown in FIGS. 1 and 2 have a structure in which the base material and the pressure-sensitive adhesive layer are directly laminated. The structure which has another layer between layers may be sufficient.

By the way, the pressure-sensitive adhesive sheet of the present invention is required to have an adhesive force of 8.0 N/25 mm or more to a rough surface of a polypropylene plate having an arithmetic mean roughness Ra of 1.0 to 3.0 μm.
The arithmetic mean roughness Ra is a value measured in accordance with JIS B 0601:1994, and specifically means a value measured according to the method described in Examples.
The adhesive strength mentioned above assumes the adhesive strength to a generally widely used polyolefin resin member having a rough surface. In other words, if the adhesive strength is 8.0 N/25 mm or more, it can be said that the adhesive sheet can sufficiently adhere even to the rough surface of such a member.
In the adhesive sheet of the present invention, the adhesive strength is 8.0 N/25 mm or more, preferably 15.0 N/25 mm or more, more preferably 20 N/25 mm or more, still more preferably 30 N/25 mm or more, and even more preferably is 40 N/25 mm or more.
In addition, in this specification, said adhesive force means the value measured based on the method as described in an Example.

A pressure-sensitive adhesive layer, a base material, and a release material, which constitute the pressure-sensitive adhesive sheet of one embodiment of the present invention, are described below.

[Adhesive layer]
The pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention is one or more styrene-based resins (A) selected from styrene-isoprene diblock copolymers (SI) and styrene-isoprene-styrene triblock copolymers (SIS). and a layer formed from a pressure-sensitive adhesive composition containing a tackifying resin (B).
A pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition containing a tackifying resin (B) together with a specific styrene-based resin (A) is suitable for polyolefin-based resin members having a rough surface. A higher adhesive strength can be exhibited compared to the case where the agent is used.

The thickness of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet of the present invention is 15 µm or more, preferably 17 µm or more, from the viewpoint of improving the adhesive strength to a polyolefin resin member having a rough surface.
Moreover, from the viewpoint of making the adhesive sheet easy to handle, the thickness of the adhesive layer is preferably 100 μm or less, more preferably 90 μm or less.

The pressure-sensitive adhesive composition, which is the material for forming the pressure-sensitive adhesive layer, may contain other resin components and pressure-sensitive adhesive additives in addition to components (A) and (B) within a range that does not impair the effects of the present invention. good.

<Styrene resin (A)>
The adhesive composition used in the present invention includes a styrene-isoprene diblock copolymer (SI) (hereinafter also referred to as "SI resin") and a styrene-isoprene-styrene triblock copolymer (SIS) (hereinafter referred to as "SIS resin (Also referred to as ") contains one or more styrene resins (A) selected from.
In one aspect of the present invention, it is preferable to use a combination of SI resin and SIS resin as the styrene-based resin (A).

In one aspect of the present invention, the content of the SI resin with respect to the total amount (100% by mass) of the styrene resin (A) is preferably 10 from the viewpoint of improving the adhesive strength to the polyolefin resin member having a rough surface. ~90% by mass, more preferably 20 to 80% by mass, still more preferably 25 to 70% by mass.

In one aspect of the present invention, the content of structural units derived from styrene with respect to the total amount (100% by mass) of the structural units of the styrene resin (A) is the adhesive strength to the polyolefin resin member having a rough surface. is preferably from 5 to 40% by mass, more preferably from 8 to 35% by mass, and still more preferably from 10 to 30% by mass.

The mass average molecular weight (Mw) of the styrene resin (A) is preferably 10,000 to 500,000, more preferably 20,000 to 400,000, still more preferably 25,000 to 350,000, and even more preferably 30,000. ~300,000.

In the pressure-sensitive adhesive composition used in one aspect of the present invention, the content of component (A) is preferably 10 to 90% by mass, relative to the total amount (100% by mass) of the active ingredients of the pressure-sensitive adhesive composition, It is preferably 20 to 80% by mass, more preferably 30 to 70% by mass.
In the present specification, the term "active ingredient of the adhesive composition" refers to the components contained in the adhesive composition excluding solvents such as water and organic solvents.

<Adhesive resin other than component (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 component (A) within a range that does not impair the effects of the present invention.
Examples of such adhesive resins include styrene-based resins other than component (A), acrylic-based resins, urethane-based resins, polyisobutylene-based resins, and the like.

<Tackifying resin (B)>
The pressure-sensitive adhesive composition used in the present invention contains a tackifying resin (B).
In this specification, the tackifying resin is a component that supplementarily improves the adhesive strength of the adhesive resin, and is an oligomer having a mass average molecular weight (Mw) of usually less than 10,000. are distinct.
The weight average molecular weight (Mw) of the tackifying resin (B) is preferably 400-4000, more preferably 800-1500.

The tackifying resin (B) is preferably one or more selected from rosin-based resins, terpene-based resins, styrene-based resins, and hydrocarbon-based resins.
As the tackifying resin (B), a hydrogenated resin obtained by hydrogenating these resins may be used.

Examples of the rosin-based resin include rosin resin, rosin ester resin, rosin phenol resin, and the like, and hydrogenated rosin-based resin obtained by hydrogenating these resins may also be used.

The terpene-based resin may be any compound having a structural unit derived from isoprene. Examples thereof include terpene resins, aromatic modified terpene resins, and terpene-phenolic resins. It may be a terpene-based resin.

Examples of styrenic resins include resins obtained by copolymerizing styrenic monomers such as α-methylstyrene or β-methylstyrene with aliphatic monomers, and hydrogenated styrene obtained by hydrogenating the resins. It may be a system resin.
The styrene resin used as the tackifying resin (B) is a resin that does not correspond to the component (A), and can be distinguished from the component (A) at least in terms of molecular weight.

Hydrocarbon-based resins include, for example, C5-based hydrocarbon resins obtained by copolymerizing C5 fractions such as pentene, isoprene, piperine, and 1,3-pentadiene produced by thermal decomposition of petroleum naphtha; heat of petroleum naphtha; C9-based hydrocarbon resins obtained by copolymerizing C9 fractions such as indene and vinyltoluene generated by decomposition; and hydrogenated hydrocarbon resins obtained by hydrogenating these.
The hydrocarbon-based resin may be any of an aliphatic hydrocarbon resin, an alicyclic hydrocarbon resin, and an aromatic hydrocarbon resin. is preferred.

The softening point of the tackifier resin (B) is preferably 70 to 170° C., more preferably 80 to 160° C., from the viewpoint of improving the adhesive strength to polyolefin resin members having rough surfaces.

When a rosin-based resin is used as the tackifying resin (B), the softening point of the rosin-based resin is preferably 80 to 130°C, more preferably 80 to 110°C, and still more preferably 80 to 90°C. .

When a terpene-based resin is used as the tackifying resin (B), the softening point of the terpene-based resin is preferably 80 to 150°C, more preferably 85 to 130°C, and still more preferably 90 to 105°C.

When a hydrocarbon-based resin is used as the tackifying resin (B), the softening point of the hydrocarbon-based resin is preferably 90 to 160°C, more preferably 100 to 155°C, and still more preferably 120 to 150°C. .

In addition, in this specification, the softening point of tackifier resin (B) means the value measured based on JISK2531.
Moreover, when two or more tackifying resins are used in combination, the weighted average value calculated from the softening point and blending amount of each tackifying resin is preferably within the above range.

In one aspect of the present invention, the content of component (B) is preferably 10 to 300 parts by mass, more preferably 30 to 200 parts by mass, relative to 100 parts by mass of the total amount of component (A) in the pressure-sensitive adhesive composition. parts, more preferably 50 to 180 parts by mass.

<Additives for Adhesives>
The pressure-sensitive adhesive composition used in one aspect of the present invention may further contain general additives for pressure-sensitive adhesives within a range that does not impair the effects of the present invention.
Examples of such adhesive additives include cross-linking agents, plasticizers (liquid resins, liquid paraffin, etc.), ultraviolet absorbers, antioxidants, rust inhibitors, antibacterial agents, insect repellents, fragrances, pigments, dyes. , a curing agent, a curing aid, a catalyst, and the like.

〔Base material〕
The substrate included in the pressure-sensitive adhesive sheet of one embodiment of the present invention is appropriately selected depending on the application, and examples thereof include paper substrates, metal substrates, porous substrates such as nonwoven fabrics, resin films, and the like.

Examples of the paper material constituting the paper substrate include thin paper, medium quality paper, fine paper, impregnated paper, coated paper, art paper, sulfate paper, glassine paper, and the like.
Examples of metals constituting the metal substrate 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 resins such as copolymers and ethylene-vinyl alcohol copolymers; polystyrene; acrylonitrile-butadiene-styrene copolymers; cellulose triacetate; polycarbonates; polyether ether ketone; polyether sulfone; polyphenylene sulfide; polyimide resins such as polyetherimide and polyimide; polyamide resins; acrylic resins;

These resin films may be composed of only one kind of resin, or may be composed of two or more kinds of resins.
Moreover, the resin film may be unstretched, or may be stretched in a uniaxial direction such as longitudinally or transversely or in a biaxial direction.
Furthermore, the resin film may be a resin film having a cavity-containing layer containing cavities inside. A resin film in which a resin layer containing no voids is further laminated on at least one surface side of the void-containing layer may be used.
In addition to these resins, the resin film may contain various additives such as UV absorbers, light stabilizers, antioxidants, antistatic agents, slip agents, antiblocking agents, and colorants.

These substrates may be used alone, or two or more of them may be combined to form a multilayer body.
The multilayer body used as the substrate includes a laminate substrate obtained by laminating a paper substrate 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 paper base material with a thermoplastic resin such as polyethylene.

The metal film included in the metal film-attached resin film can be formed from a metal such as aluminum, tin, chromium, or titanium.
As a method for forming a metal film on the surface of a resin film, these metals are vapor-deposited by a PVD (physical vapor deposition) method such as vacuum deposition, sputtering, or ion plating, and metal foils made of the above metals are generally used. and a method of sticking using a specific adhesive.

When the base material used in one embodiment of the present invention is a resin film or a laminate base material, from the viewpoint of improving adhesion to the pressure-sensitive adhesive layer, the surface of these base materials is subjected to an oxidation method or an uneven surface. A surface treatment such as a curing method, or a primer treatment may be applied.
The oxidation method is not particularly limited, and examples thereof include corona discharge treatment, plasma treatment, chromic acid oxidation (wet), flame treatment, hot air treatment, ozone/ultraviolet irradiation treatment, and the like.
The roughening method is not particularly limited, and includes, for example, a sandblasting method, a solvent treatment method, and the like.

The thickness of the substrate is preferably 5 to 1000 μm, more preferably 10 to 500 μm, still more preferably 12 to 250 μm, still more preferably 15 to 150 μm.

[Release material]
As the release material included in the pressure-sensitive adhesive sheet of one embodiment of the present invention, a release material subjected to double-sided release treatment, a release material subjected to single-sided release treatment, or the like is used, and a release agent is applied to a base material for release material. etc.
Examples of the substrate for the release material include paper substrates such as glassine paper, coated paper, and woodfree paper, laminated paper obtained by laminating a thermoplastic resin such as polyethylene on these paper substrates, polyethylene terephthalate resin, and polybutylene terephthalate. Resins, polyester resin films such as polyethylene naphthalate resins, plastic films such as polyolefin resin films such as polypropylene resins and polyethylene resins, and the like.
Examples of release agents include silicone-based resins, olefin-based resins, long-chain alkyl-based resins, alkyd-based resins, fluorine-based resins, and the like.

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

[Method for producing adhesive sheet]
The method for producing the pressure-sensitive adhesive sheet of the present invention is not particularly limited. A manufacturing method having a step of forming a layer is mentioned.
In order to improve the workability of coating the substrate or release material onto the surface of the substrate or release material, the pressure-sensitive adhesive composition of the present invention, which is the material for forming the pressure-sensitive adhesive layer, is further diluted with an organic solvent. It is preferably diluted and in the form of a solution.

Examples of organic solvents include 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 still more preferably 15 to 60% by mass.

Examples of methods for applying the solution of the adhesive composition onto the substrate or release material include spin coating, spray coating, bar coating, knife coating, roll coating, blade coating, die coating, and gravure. A coat method and the like can be mentioned.

As a specific manufacturing method, as a manufacturing method of the pressure-sensitive adhesive sheet 1a with a substrate as shown in FIG. and forming the pressure-sensitive adhesive layer 12 .
Further, as a method for producing the adhesive sheet 1b with a substrate as shown in FIG. After forming the layer 12, the method of sticking together the exposed surface of the adhesive layer 12 and the base material 11, etc. are mentioned.
Furthermore, as a method for producing the double-sided pressure-sensitive adhesive sheet 1c with a substrate as shown in FIG. 12 and 12′ are formed, or two release materials are prepared, and a solution of the adhesive composition is directly applied on the release-treated surface of each release material, and dried to form an adhesive layer. are formed, and then adhesive layers 12a and 12b formed on two release materials are adhered to both surfaces of the base material 11, for example.
Then, as a method for producing the substrate-free adhesive sheet 1d as shown in FIG. After the layer 12 is formed, another release material 13b is adhered to the exposed surface of the pressure-sensitive adhesive layer 12, for example.

In the following examples and comparative examples, methods for measuring various physical properties are as described below.
<Mass average molecular weight (Mw)>
Using a gel permeation chromatograph (manufactured by Tosoh Corporation, product name "HLC-8020"), measurement was performed under the following conditions and measured in terms of standard polystyrene.
(Measurement condition)
・Column: "TSK guard column HXL-H", "TSK gel GMHXL" (two), and "TSK gel G2000HXL" (both manufactured by Tosoh Corporation) are sequentially connected ・Column temperature: 40 ° C.
・Developing solvent: tetrahydrofuran ・Flow rate: 1.0 mL/min

<Softening point>
Measured according to JIS K 2531.

<Arithmetic mean roughness Ra, maximum cross-sectional height Rt>
Using a surface roughness measuring machine (manufactured by Mitutoyo Co., Ltd., product name "SV3000S4", stylus type), it was measured in accordance with JIS B0601:1994. In addition, the measurement conditions are as follows.
• Reference length = 2.5 mm, λc = 0.25 mm, λs = 0.008 mm, evaluation length = 10 mm, scanning speed = 1.0 mm/s, range = 800 µm.

<Bending resistance of base material>
A sample for measurement was obtained by cutting the base material used in Examples and Comparative Examples into a rectangle of 38 mm in length and 25 mm in width.
For the measurement sample, using a bending resistance tester (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name "Gurley type flexibility tester"), in an environment of 23 ° C. and 50% RH (relative humidity), JIS According to the Gurley method of L 1096 (1999) 8.20.1, the bending direction of the base material is measured in the flow direction (MD direction) during molding of the base material and in the direction perpendicular to the MD direction (TD direction). degrees were measured respectively.

<Tear strength of substrate>
A sample for measurement was obtained by cutting the base material used in Examples and Comparative Examples into a rectangular shape of 75 mm in length and 63 mm in width.
Four sheets of the measurement sample are stacked, and an Elmendorf tear tester (manufactured by Toyo Seiki Seisakusho Co., Ltd.) is used to perform a tear test in accordance with JIS K 7128 in an environment of 23 ° C. and 50% RH (relative humidity). , four times each in the MD direction and the TD direction of the substrate. Then, the average value of each of the four values measured in the MD direction and the TD direction (tear strength for 4 substrates) is calculated, and the value of 1/4 of the average value is the tear strength of the substrate. bottom.

<Thickness of adhesive layer>
Using a pressure-sensitive adhesive layer constant pressure thickness measuring device (manufactured by Teclock Co., Ltd., product name “PG-02J”), the thickness was measured according to JIS K6783, Z1702 and Z1709.

Examples 1-43
Each component of the type and blending amount (solid content ratio) shown in Table 1 was added, diluted with toluene, and stirred to prepare a pressure-sensitive adhesive composition solution having a solid content concentration of 50% by mass.
Then, on the release-treated surface of a release sheet (manufactured by Lintec Corporation, product name “SP-PET751130”, thickness 75 μm), the prepared solution of the adhesive composition is applied to form a coating film, and the coating film is formed. was dried at 100° C. for 1 minute to form pressure-sensitive adhesive layers having the thicknesses shown in Table 1, respectively.
Then, on the adhesive surface of the formed adhesive layer, a substrate of the type shown in Table 1 was laminated to obtain an adhesive sheet having the same structure as the adhesive sheet 1b shown in FIG. 1(b).

Comparative Examples 1-6
To 100 parts by mass (solid content ratio) of the acrylic resin (1) described below, the crosslinking agent described below is added in the amount (solid content ratio) shown in Table 1, diluted with ethyl acetate, and the pressure-sensitive adhesive composition A solution of each was prepared.
Then, on the release-treated surface of a release sheet (manufactured by Lintec Corporation, product name “SP-PET751130”, thickness 75 μm), the prepared solution of the adhesive composition is applied to form a coating film, and the coating film is formed. was dried at 100° C. for 1 minute to form pressure-sensitive adhesive layers having the thicknesses shown in Table 1, respectively.
Then, on the adhesive surface of the formed adhesive layer, a substrate of the type shown in Table 1 was laminated to obtain an adhesive sheet having the same structure as the adhesive sheet 1b shown in FIG. 1(b).

The details of the substrates used in Examples and Comparative Examples are as follows.
· PET film: manufactured by Toray Industries, Inc., product name “Lumirror (R) T-60”, polyethylene terephthalate (PET) film with a thickness of 50 μm.
• Foamed PET film (1): a 50 μm thick foamed PET film having a cavity-containing layer. Bending strength: MD direction = 0.21 mN, TD direction = 0.22 mN, Tear strength: MD direction = 270 mN, TD direction = 294 mN.
- Foamed PET film (2): manufactured by Toyobo Co., Ltd., product name "Crisper K2411". A 50 μm thick foamed PET film with a void-containing layer. Bending resistance: MD direction = 0.25 mN, TD direction = 0.28 mN, Tear strength: MD direction = 319 mN, TD direction = 294 mN.
- Foamed PP film: manufactured by Yupo Corporation, product name "Yupo SGP80", 80 µm thick foamed polypropylene (PP) film having a cavity-containing layer.

The details of each component used in the preparation of the pressure-sensitive adhesive composition are as follows.
<Adhesive resin>
Styrene-based resin (1): SIS resin (triblock)/SI resin (diblock) = 75/25 (mass%) mixed resin, styrene content = 15 mass%, Mw = 190,000.
Styrene-based resin (2): SIS resin (triblock)/SI resin (diblock) = 25/75 (mass%) mixed resin, styrene content = 15 mass%, Mw = 160,000.
Styrene-based resin (3): SIS resin (triblock)/SI resin (diblock) = 35/65 (mass%) mixed resin, styrene content = 25 mass%, Mw = 180,000.
Acrylic resin (1): Mw 550,000 acrylic obtained by copolymerizing n-butyl acrylate (BA), 2-ethylhexyl acrylate (2EHA), acrylic acid (AAc), and 2-hydroxyethyl acrylate (HEA) Copolymer (Constituent unit ratio: BA/EHA/AAc/HEA = 47.0/47.0/5.5/0.5 (% by mass)).

<Tackifying resin>
- Terpene-based resin (1): manufactured by Yasuhara Chemical Co., Ltd., product name "YS Resin PX1150N", non-hydrogenated terpene-based resin, Mw = less than 10,000, softening point = 115°C.
- Terpene resin (2): manufactured by Yasuhara Chemical Co., Ltd., product name "YS polyester U115", terpene phenol resin, Mw = less than 10,000, softening point = 115°C.
- Terpene-based resin (3): manufactured by Yasuhara Chemical Co., Ltd., product name "YS Resin PX1000", non-hydrogenated terpene-based resin, Mw = less than 10,000, softening point = 100°C.
- Terpene-based resin (4): manufactured by Yasuhara Chemical Co., Ltd., product name "Clearon P105", hydrogenated terpene-based resin, Mw = less than 10,000, softening point = 105°C.

- Hydrocarbon-based resin (1): Arakawa Chemical Industries, Ltd., product name "Arcon P-100", alicyclic saturated hydrocarbon-based resin, Mw = less than 10,000, softening point = 100°C.
- Hydrocarbon-based resin (2): Arakawa Chemical Industries, Ltd., product name "Arcon P-90", alicyclic saturated hydrocarbon-based resin, Mw = less than 10,000, softening point = 90°C.
- Hydrocarbon resin (3): manufactured by Arakawa Chemical Industries, Ltd., product name "Arcon P-115", alicyclic saturated hydrocarbon resin, Mw = less than 10,000, softening point = 115°C.
- Hydrocarbon resin (4): manufactured by Arakawa Chemical Industries, Ltd., product name "Arcon P-125", alicyclic saturated hydrocarbon resin, Mw = less than 10,000, softening point = 125°C.
- Hydrocarbon resin (5): manufactured by Arakawa Chemical Industries, Ltd., product name "Arcon P-140", alicyclic saturated hydrocarbon resin, Mw = less than 10,000, softening point = 140°C.
- Hydrocarbon-based resin (6): Nippon Zeon Co., Ltd., product name "Quinton LB406", hydrocarbon-based resin, Mw = less than 10,000, softening point = 90°C.

- Styrene-based resin (1): copolymer of styrene-based monomer and aliphatic monomer, Mw = less than 10,000, softening point = 95°C.

- Rosin-based resin (1): manufactured by Arakawa Chemical Industries, Ltd., product name "Pine Crystal KE-100", rosin ester-based resin, Mw = less than 10,000, softening point = 100°C.
- Rosin-based resin (2): AR BROWN, product name "Sylvalite RE85L", non-hydrogenated rosin-based resin, Mw = less than 10,000, softening point = 85°C.
· Rosin-based resin (3): manufactured by Arakawa Chemical Industries, Ltd., product name "Ester Gum HP", hydrogenated rosin ester-based resin, Mw = less than 10,000, softening point = 80°C or higher.

<Other additives>
- Liquid resin: manufactured by Yasuhara Chemical Co., Ltd., product name "Dymaron", terpene resin.
- Liquid paraffin: manufactured by MORESCO Co., Ltd., product name "MORESCO White P-350P".
· Antioxidant: product name "ADEKA STAB AO60" manufactured by ADEKA Corporation, hindered phenol-based antioxidant.
Ultraviolet absorber: manufactured by ADEKA Corporation, product name "ADEKA STAB LA32", benzotriazole-based ultraviolet absorber.
· Cross-linking agent: Tosoh Corporation, product name "Coronate L", isocyanate-based cross-linking agent.

Using the pressure-sensitive adhesive sheets produced in Examples and Comparative Examples, the "adhesive force to the rough surface of the polypropylene plate" was measured. Table 1 shows the results.
<Adhesive strength to rough surface of polypropylene (PP) plate>
The adhesive sheets prepared in Examples and Comparative Examples were cut into rectangles with a length of 150 mm and a width of 25 mm. A 2-kg roller was used to apply to the rough surface of a polypropylene plate having a rough surface with a cross-sectional height Rt of 17 μm, and allowed to stand under an environment of 23° C. and 50% RH (relative humidity) for 24 hours.
After standing, the adhesion to the rough surface of the polypropylene (PP) plate was measured at a pulling rate of 300 mm/min by a 180° peeling method according to JIS Z0237:2000.

As can be seen from Table 1, the pressure-sensitive adhesive sheets produced in Examples 1-43 had higher adhesive strength to the rough surface of the polypropylene plate than the pressure-sensitive adhesive sheets of Comparative Examples 1-6.

1a, 1b, 1c, 1d adhesive sheet 11 base material 12, 12a, 12b adhesive layer 13, 13a, 13b release material

Claims (2)

Contains one or more styrene resins (A) selected from styrene-isoprene diblock copolymer (SI) and styrene-isoprene-styrene triblock copolymer (SIS), and tackifying resin (B) A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition,
The content of the styrene-isoprene diblock copolymer (SI) is 51 to 70% by mass with respect to the total amount (100% by mass) of the styrene resin (A),
The tackifying resin (B) is one or more selected from rosin-based resins, terpene-based resins, styrene-based resins, and hydrocarbon-based resins,
The terpene-based resin is a terpene resin, an aromatic modified terpene resin, or a terpene phenol-based resin,
The hydrocarbon-based resin has a softening point of 115 to 160° C.,
In the pressure-sensitive adhesive composition, the content of component (B) is 100 to 300 parts by mass with respect to 100 parts by mass of the total amount of component (A) in the pressure-sensitive adhesive composition,
The pressure-sensitive adhesive layer has a thickness of 15 μm or more and 100 μm or less,
Based on JIS Z0237: 2000, the rough surface of a polypropylene plate having a rough surface with an arithmetic average roughness Ra of 1.0 to 3.0 μm, measured by a 180° peeling method at a pulling speed of 300 mm / min. A pressure-sensitive adhesive sheet having an adhesive strength of 16.7 N /25 mm or more and 59.5 N/25 mm or less. 2. The pressure-sensitive adhesive sheet according to claim 1, wherein the content of structural units derived from styrene is 5 to 40% by mass with respect to the total amount (100% by mass) of the structural units of the styrene-based resin (A).

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