KR102648166B1 - Adhesive sheet - Google Patents

Abstract

An adhesive sheet including an adhesive layer is provided. The adhesive layer contains polymer A and polymer B. The polymer B has an EG group selected from the group consisting of an EG1 group (a hydrocarbon group having 12 to 22 carbon atoms that may be halogenated) and an EG2 group (a halogenated hydrocarbon group having 11 or less carbon atoms) at its terminal. It has side chains. The adhesive sheet has an adhesive force N1 of 10 N/25 mm or less after being bonded to a stainless steel plate and heated at 80°C for 5 minutes at 23°C for 30 minutes, and has an adhesive force N2 of 23°C for 30 minutes after being bonded to a stainless steel plate. It is more than twice the adhesive force N1.

Description

Adhesive sheet {ADHESIVE SHEET}

The present invention relates to an adhesive sheet.

This application claims priority based on Japanese Patent Application 2018-152045 filed on August 10, 2018, the entire contents of which are incorporated herein by reference.

The adhesive sheet firmly adheres to the adherend and is used for purposes such as adhesion between adherends, fixing articles to the adherend, and reinforcing the adherend. Conventionally, for this purpose, adhesive sheets that exhibit high adhesive strength have been used from the beginning of sticking.

In addition, in recent years, adhesive sheets have been proposed that exhibit low adhesive strength at the initial stage of sticking to the adherend and can greatly increase the adhesive strength thereafter (Japanese Patent No. 6223836, Japanese Patent No. 5890596, Japanese Patent Publication No. 5951153). According to the adhesive sheet having these characteristics, before the adhesive strength increases, it exhibits re-adhesion (reworkability) useful for suppressing yield reduction due to adhesion errors or adhesion damage of the adhesive sheet, and after the adhesive strength increases, the adhesive sheet maintains its original state. It can demonstrate strong adhesion suitable for the purpose of use.

As described above, the present inventors conducted further studies in order to provide an adhesive sheet that exhibits low adhesive strength at the initial stage of sticking and can greatly increase the adhesive strength thereafter. As a result, it was discovered that a polymer having a side chain with a specific end group is useful as a component of the pressure-sensitive adhesive layer included in the pressure-sensitive adhesive sheet, and the present invention was completed.

According to this specification, an adhesive sheet including an adhesive layer is provided. The adhesive layer contains polymer A and polymer B. The polymer B has a side chain having an EG group at the terminal. The monomer component forming the polymer B includes monomer m1 that introduces the side chain into the polymer B. Here, the EG group is,

EG1 group: a hydrocarbon group having 12 to 22 carbon atoms, which may be halogenated, and

EG2 group: selected from the group consisting of halogenated hydrocarbon groups having 11 or less carbon atoms. The adhesive sheet has an adhesive force N1 of 10 N/25 mm or less after being bonded to a stainless steel plate and heated at 80°C for 5 minutes at 23°C for 30 minutes, and has an adhesive force N2 of 23°C for 30 minutes after being bonded to a stainless steel plate. It is more than twice the adhesive force N1.

In this way, according to the adhesive layer containing polymer B having a side chain having an EG group at the terminal in combination with polymer A, N1 (hereinafter also referred to as initial adhesive force) is suppressed to 10 N/25mm or less, and further, the adhesive force is reduced to N1. An adhesive sheet in which N2 (hereinafter also referred to as adhesive force after heating) increases by more than two times can be suitably realized. In addition, hereinafter, a side chain having an EG group at the terminal may be referred to as an EG side chain. Similarly, a side chain having an EG1 group at the terminal may be referred to as an EG1 side chain, and a side chain having an EG2 group at the terminal may be referred to as an EG2 side chain.

As the polymer A, an acrylic polymer can be preferably used from the viewpoint of ease of control of the glass transition temperature and control of adhesive properties.

The glass transition temperature (T _A ) of the polymer A is preferably less than 0°C. Since the adhesive containing such polymer A exhibits moderate fluidity, it is suitable for the realization of a pressure-sensitive adhesive sheet that initially has low adhesiveness and whose adhesive strength increases significantly when heated.

In some embodiments, the weight average molecular weight of the polymer B is preferably 1×10 ⁴ or more and 10×10 ⁴ or less. Polymer B, which has a weight average molecular weight (Mw) in the above range, exhibits moderate mobility in the adhesive layer containing polymer A, making it possible to create an adhesive sheet that is initially low-adhesive and whose adhesive strength increases significantly when heated. Suitable.

As the polymer B, an acrylic polymer can be preferably used from the viewpoint of polymerization reactivity and ease of controlling Mw. When the polymer A is an acrylic polymer, using an acrylic polymer as the polymer B is advantageous also from the viewpoint of compatibility.

The monomer m1 may include (meth)acrylate having the EG1 group at the ester terminal, that is, EG1 (meth)acrylate. By using EG1 (meth)acrylate, polymer B having an EG1 side chain can be suitably formed.

The monomer m1 may include (meth)acrylate having the EG2 group at the ester terminal, that is, EG2 (meth)acrylate. By using EG2 (meth)acrylate, polymer B having an EG2 side chain can be suitably formed.

The monomer component forming polymer B preferably contains 2% by weight or more of the monomer m1. Polymer B formed from a monomer component of this composition is suitable for the realization of an adhesive sheet that initially has low adhesiveness and whose adhesive strength increases significantly when heated.

The monomer component forming polymer B may include, in addition to monomer m1, another monomer copolymerizable with monomer m1. Suitable examples of the other monomers include (meth)acrylate having an alkyl group of 11 or less carbon atoms at the ester terminal, that is, C _1-11 alkyl (meth)acrylate. The pressure-sensitive adhesive sheet disclosed herein can be suitably implemented using polymer B of this composition.

In the adhesive layer, the content of the polymer B relative to 100 parts by weight of the polymer A can be, for example, in the range of 1 part by weight or more and 100 parts by weight or less. According to the pressure-sensitive adhesive layer of this composition, it is easy to obtain a pressure-sensitive adhesive sheet that initially has low adhesiveness and whose adhesive strength increases significantly when heated.

The adhesive sheet disclosed herein is provided with a support substrate having a first side and a second side, and the adhesive layer is laminated on at least the first side of the support substrate, that is, in the form of a pressure-sensitive adhesive sheet with a substrate. It can be implemented. Such a pressure-sensitive adhesive sheet with a base material can have good handling and processability. As the support substrate, for example, one having a thickness of 30 μm or more can be preferably employed.

In addition, an appropriate combination of the above-described elements may also be included in the scope of the invention for which protection by patent is sought by this patent application.

1 is a cross-sectional view schematically showing the structure of an adhesive sheet according to one embodiment.
Figure 2 is a cross-sectional view schematically showing the structure of an adhesive sheet according to another embodiment.
Figure 3 is a cross-sectional view schematically showing the structure of an adhesive sheet according to another embodiment.

Hereinafter, preferred embodiments of the present invention will be described. Matters other than those specifically mentioned in this specification and matters necessary for practicing the present invention can be understood by those skilled in the art based on the teachings regarding the implementation of the invention described in this specification and the technical common sense at the time of filing the application. The present invention can be implemented based on the content disclosed in this specification and common technical knowledge in the field.

Additionally, in the drawings below, members and parts that exert the same function may be described with the same reference numerals, and overlapping descriptions may be omitted or simplified. In addition, the embodiments described in the drawings are modeled to clearly explain the present invention, and do not necessarily accurately represent the size or scale of the actually provided product.

In addition, in this specification, “acrylic polymer” refers to a polymer containing monomer units derived from (meth)acrylic monomers in the polymer structure, and typically contains 50% by weight of monomer units derived from (meth)acrylic monomers. It refers to a polymer contained in a proportion exceeding that of In addition, a (meth)acrylic monomer refers to a monomer having at least one (meth)acryloyl group in one molecule. Here, “(meth)acryloyl group” refers comprehensively to acryloyl group and methacryloyl group. Therefore, the concept of (meth)acrylic monomer herein may include both a monomer having an acryloyl group (acrylic monomer) and a monomer having a methacryloyl group (methacrylic monomer). Similarly, in this specification, “(meth)acrylic acid” refers comprehensively to acrylic acid and methacrylic acid, and “(meth)acrylate” refers to acrylate and methacrylate, respectively.

<Structure example of adhesive sheet>

The adhesive sheet disclosed herein is comprised including an adhesive layer. The pressure-sensitive adhesive sheet disclosed herein may be in the form of a pressure-sensitive adhesive sheet with a base material in which the pressure-sensitive adhesive layer is laminated on one or both sides of a support base material, or may be in the form of a base-less pressure-sensitive adhesive sheet without a support base material. Hereinafter, the supporting substrate may simply be referred to as “substrate.”

The structure of the adhesive sheet according to one embodiment is schematically shown in FIG. 1. This adhesive sheet 1 includes a sheet-shaped support substrate 10 having a first face 10A and a second face 10B, and an adhesive layer 21 provided on the first face 10A side. It is constructed as a single-sided adhesive sheet with a base material. The adhesive layer 21 is adhered to the first surface 10A side of the support substrate 10. The adhesive sheet 1 is used by attaching the adhesive layer 21 to an adherend. As shown in FIG. 1, the adhesive sheet 1 before use (i.e., before sticking to an adherend) has at least the surface (adhesive surface) 21A of the adhesive layer 21. The side opposite may be a component of the adhesive sheet 100 with a release liner in contact with the release liner 31, which has a peelable surface (release surface). As the release liner 31, for example, one configured to form a release layer with a release treatment agent on one side of a sheet-like substrate (liner substrate) so that one side becomes a release surface can be preferably used. Alternatively, the release liner 31 is omitted, and the adhesive sheet 1 is wound using the support substrate 10 whose second surface 10B is a release surface, thereby attaching the adhesive surface 21A to the support substrate 10. ) may be in contact with the second surface 10B (roll shape). When sticking the adhesive sheet 1 to an adherend, the release liner 31 or the second surface 10B of the support substrate 10 is peeled from the adhesive surface 21A, and the exposed adhesive surface 21A is avoided. Press into the complex.

The structure of an adhesive sheet according to another embodiment is schematically shown in FIG. 2. This adhesive sheet 2 includes a sheet-shaped support substrate 10 having a first face 10A and a second face 10B, an adhesive layer 21 provided on the first face 10A side, and a It is configured as a double-sided adhesive sheet with a base material and an adhesive layer 22 provided on the two sides 10B. The adhesive layer (first adhesive layer) 21 is on the first side 10A of the support substrate 10, and the adhesive layer (second adhesive layer) 22 is on the second side 10B of the support substrate 10. Well, each is fixed. The adhesive sheet 2 is used by attaching adhesive layers 21 and 22 to different locations on an adherend. The locations where the adhesive layers 21 and 22 are attached may be separate locations on different members or may be different locations within a single member. As shown in FIG. 2, the adhesive sheet 2 before use has a surface (first adhesive surface) 21A of the adhesive layer 21 and a surface (second adhesive surface) 22A of the adhesive layer 22. This may be a component of the pressure-sensitive adhesive sheet 200 with a release liner in contact with the release liners 31 and 32, where at least the sides facing the adhesive layers 21 and 22 are release surfaces, respectively. As the release liners 31 and 32, for example, those configured to form a release layer with a release treatment agent on one side of a sheet-like substrate (liner substrate) so that one side becomes a release surface can be preferably used. Alternatively, the release liner 32 may be omitted, and the release liner 31 having both sides as release surfaces may be used, and the adhesive sheet 2 may be overlapped with this and wound in a spiral shape to form a second adhesive surface 22A. An adhesive sheet with a release liner may be formed in a form (roll form) in contact with the back of the release liner 31.

The structure of an adhesive sheet according to another embodiment is schematically shown in FIG. 3. This adhesive sheet 3 is configured as a double-sided adhesive sheet made of an inorganic material including an adhesive layer 21. The adhesive sheet 3 has a first adhesive surface 21A formed by one surface (first surface) of the adhesive layer 21, and a first adhesive surface 21A formed by the other surface (second surface) of the adhesive layer 21. 2 The adhesive surface 21B is used by attaching it to different locations on the adherend. In the adhesive sheet 3 before use, as shown in FIG. 3, the first adhesive surface 21A and the second adhesive surface 21B each have at least the side facing the adhesive layer 21 as a peeling surface. It may be a component of the adhesive sheet 300 with a release liner in contact with the release liners 31 and 32. Alternatively, the release liner 32 may be omitted, and the release liner 31 having both sides as release surfaces may be used, and the adhesive sheet 3 may be overlapped with this and wound in a spiral shape to form the second adhesive surface 21B. An adhesive sheet with a release liner may be formed in a form (roll form) in contact with the back of the release liner 31.

Additionally, the concept of adhesive sheet referred to herein may include what is referred to as adhesive tape, adhesive film, adhesive label, etc. The adhesive sheet may be in the form of a roll, a sheet, or may be cut, punched, etc. into an appropriate shape depending on the purpose or usage mode. The adhesive layer in the technology disclosed herein is typically formed continuously, but is not limited to this, and may be formed in a regular or random pattern such as dots or stripes, for example.

<Adhesive layer>

The pressure-sensitive adhesive sheet disclosed herein includes a pressure-sensitive adhesive layer containing polymer A and polymer B. This adhesive layer may be formed from an adhesive composition containing polymer A or its precursor and polymer B. The form of the adhesive composition is not particularly limited, and may be in various forms such as water dispersion type, solvent type, hot melt type, and active energy ray curing type (eg, photocuring type).

(Polymer A)

As polymer A, in the field of adhesives, known acrylic polymers, rubber-based polymers, polyester-based polymers, urethane-based polymers, polyether-based polymers, polyamide-based polymers, silicone-based polymers, and fluorine-based polymers have rubber elasticity in the room temperature range. One or two or more types of the various polymers shown can be used.

The glass transition temperature (T _A ) of polymer A is typically less than 0°C. Since the adhesive containing such polymer A exhibits appropriate fluidity (e.g., mobility of the polymer chains contained in the adhesive), it is initially low adhesive and can be used to realize an adhesive sheet whose adhesive strength increases significantly when heated. Suitable. From the viewpoint of improvement in adhesion after heating and low-temperature characteristics, T _A of polymer A is usually less than -10°C, preferably less than -20°C, may be less than -30°C, and may be less than -35°C. In some embodiments, T _A of polymer A may be less than -40°C or less than -50°C. The lower limit of T _A is not particularly limited. From the viewpoint of ease of availability of the material and improvement of cohesion of the adhesive layer, polymer A with T _A of -80°C or higher, -70°C or higher, or -65°C or higher can be preferably employed. From the viewpoint of making it easy to suppress the initial adhesive force, in some embodiments, T _A may be, for example, -63°C or higher, -55°C or higher, -50°C or higher, or -45°C or higher.

Here, in this specification, the glass transition temperature (Tg) of a polymer refers to a nominal value described in literature, catalogs, etc., or Tg calculated by the Fox equation based on the composition of the monomer component used in preparing the polymer. As described below, the Fox equation is a relationship between the Tg of a copolymer and the glass transition temperature Tgi of a homopolymer obtained by independently polymerizing each of the monomers constituting the copolymer.

1/Tg=Σ(Wi/Tgi)

In the Fox equation, Tg is the glass transition temperature of the copolymer (unit: K), Wi is the weight fraction of monomer i in the copolymer (copolymerization ratio by weight), and Tgi is the glass transition temperature of the homopolymer of monomer i. Indicates the transition temperature (unit: K). When the target polymer for specification of Tg is a homopolymer, the Tg of the homopolymer and the target polymer Tg match.

As the glass transition temperature of the homopolymer used to calculate Tg, the value described in known data is used. Specifically, the numerical values are illustrated in “Polymer Handbook” (3rd edition, John Wiley & Sons, Inc., 1989). For monomers for which multiple types of values are described in the Polymer Handbook, the highest value is adopted.

As the glass transition temperature of the homopolymer of monomers not described in the Polymer Handbook, the value obtained by the following measurement method is used.

Specifically, 100 parts by weight of monomer, 0.2 parts by weight of 2,2'-azobisisobutyronitrile, and 200 parts by weight of ethyl acetate as a polymerization solvent were added to a reactor equipped with a thermometer, stirrer, nitrogen introduction pipe, and reflux cooling pipe. and stirred for 1 hour while circulating nitrogen gas. After removing oxygen in the polymerization system in this way, the temperature is raised to 63°C and reaction is carried out for 10 hours. Next, it is cooled to room temperature to obtain a homopolymer solution with a solid content concentration of 33% by weight. Next, this homopolymer solution is applied on a release liner and dried to produce a test sample (sheet-like homopolymer) with a thickness of about 2 mm. This test sample was punched into a disk shape with a diameter of 7.9 mm, sandwiched between parallel plates, and subjected to shear strain at a frequency of 1 Hz using a viscoelasticity tester (manufactured by TA Instruments Japan, model name "ARES") in a temperature range of -70°C to Viscoelasticity is measured in shear mode at 150°C and a temperature increase rate of 5°C/min, and the temperature corresponding to the peak top temperature of tanδ is taken as the Tg of the homopolymer.

Although not particularly limited, it is appropriate that the weight average molecular weight (Mw) of polymer A is usually approximately 5×10 ⁴ or more. According to the polymer A of this Mw, an adhesive showing good cohesiveness is easy to obtain. In some embodiments, the Mw of polymer A may be, for example, 10×10 ⁴ or more, 20×10 ⁴ or more, or 30×10 ⁴ or more. Additionally, it is appropriate that the Mw of polymer A is usually approximately 500×10 ⁴ or less. Polymer A of this Mw is suitable for the realization of an adhesive sheet that has low adhesive strength at the initial stage of application because it is easy to form an adhesive that exhibits appropriate fluidity (mobility of polymer chains) and whose adhesive strength increases significantly when heated. .

In addition, in this specification, the Mw of Polymer A and Polymer B can be calculated in terms of polystyrene by gel permeation chromatography (GPC). More specifically, Mw can be measured according to the methods and conditions described in the examples described later.

As the polymer A in the adhesive sheet disclosed herein, an acrylic polymer can be preferably employed from the viewpoint of ease of controlling the glass transition temperature ( _TA ) and controlling the adhesive properties. When an acrylic polymer is used as polymer A, good compatibility with polymer B tends to be easily obtained. Good compatibility between polymer A and polymer B is desirable because it can contribute to reducing the initial adhesive force and improving the adhesive force after heating through improved mobility of polymer B in the adhesive layer.

An acrylic polymer is, for example, a polymer containing 50% by weight or more of monomer units derived from alkyl (meth)acrylate, that is, 50% by weight or more of the total amount of monomer components forming the alkyl (meth)acrylate is an alkyl (meth)acrylate. It may be a polymer. As the (meth)acrylic acid alkyl ester, a (meth)acrylic acid alkyl ester having a straight or branched alkyl group having 1 to 20 carbon atoms (i.e., C _1-20 ) can be preferably used. Since it is easy to balance the properties, the proportion of (meth)acrylic acid C _1-20 alkyl ester in the total amount of monomer components may be, for example, 50% by weight or more, 60% by weight or more, or 70% by weight or more. do. For the same reason, the proportion of (meth)acrylic acid C _1-20 alkyl ester in the total amount of monomer components may be, for example, 99.9% by weight or less, 98% by weight or less, or 95% by weight or less. In some embodiments, the proportion of (meth)acrylic acid C _1-20 alkyl ester in the total amount of monomer components may be, for example, 90% by weight or less, 85% by weight or less, or 80% by weight or less.

Non-limiting specific examples of (meth)acrylic acid C _1-20 alkyl esters include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, Isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, (meth)acrylate ) Octyl acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, (meth)acrylate Undecyl acrylate, dodecyl (meth)acrylate, tridecyl (meth)acrylate, tetradecyl (meth)acrylate, pentadecyl (meth)acrylate, hexadecyl (meth)acrylate, heptadecyl (meth)acrylate, (meth)acrylic acid Stearyl, isostearyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, etc. are mentioned.

Among these, it is preferable to use at least a (meth)acrylic acid C _1-18 alkyl ester, and it is more preferable to use at least a (meth)acrylic acid C _1-14 alkyl ester. In some embodiments, the acrylic polymer is at least one selected from (meth)acrylic acid C _4-12 alkyl esters (preferably acrylic acid C _4-10 alkyl esters, for example acrylic acid C _6-10 alkyl esters), It can be contained as a monomer unit. For example, an acrylic polymer containing one or both of n-butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA) is preferred, and an acrylic polymer containing at least 2EHA is particularly preferred. Examples of other (meth)acrylic acid C _1-18 alkyl esters that can be preferably used include methyl acrylate, methyl methacrylate (MMA), n-butyl methacrylate (BMA), and 2-ethylhexyl methacrylate (2EHMA). , isostearyl acrylate (ISTA), etc.

The monomer unit constituting the acrylic polymer may contain an alkyl (meth)acrylate as the main component and, if necessary, another monomer (copolymerizable monomer) copolymerizable with the alkyl (meth)acrylate. As the copolymerizable monomer, a monomer having a polar group (for example, a carboxyl group, a hydroxyl group, a nitrogen atom-containing ring, etc.) can be suitably used. A monomer having a polar group can be helpful for introducing crosslinking points into the acrylic polymer or increasing the cohesion of the acrylic polymer. Copolymerizable monomers can be used individually or in combination of two or more types.

Non-limiting specific examples of copolymerizable monomers include the following.

Carboxyl group-containing monomers: for example, acrylic acid, methacrylic acid, carboxyethylacrylate, carboxypentylacrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, isocrotonic acid, etc.

Monomers containing acid anhydride groups: for example, maleic anhydride, itaconic anhydride.

Hydroxyl group-containing monomers: for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, (meth)acrylic acid. ) 4-hydroxybutyl acrylic acid, 6-hydroxyhexyl (meth)acrylic acid, 8-hydroxyoctyl (meth)acrylic acid, 10-hydroxydecyl (meth)acrylic acid, 12-hydroxylauryl (meth)acrylic acid, ( Hydroxyalkyl (meth)acrylate such as 4-hydroxymethylcyclohexyl)methyl (meth)acrylate, etc.

Monomers containing sulfonic acid groups or phosphoric acid groups: for example, styrenesulfonic acid, allylsulfonic acid, sodium vinylsulfonate, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth) ) Acrylates, (meth)acryloyloxynaphthalenesulfonic acid, 2-hydroxyethyl acryloyl phosphate, etc.

Monomers containing epoxy groups: For example, epoxy group-containing acrylates such as glycidyl (meth)acrylate or 2-ethylglycidyl (meth)acrylate, allyl glycidyl ether, glycidyl (meth)acrylate, etc. .

Monomers containing cyano groups: such as acrylonitrile, methacrylonitrile, etc.

Isocyanate group-containing monomer: For example, 2-isocyanatoethyl (meth)acrylate, etc.

Monomers containing amide groups: such as (meth)acrylamide; N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dipropyl(meth)acrylamide, N,N-diisopropyl(meth)acrylamide, N, N,N-dialkyl (meth)acrylamide, such as N-di(n-butyl)(meth)acrylamide and N,N-di(t-butyl)(meth)acrylamide; N-alkyl (meth)acrylamide, such as N-ethyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide, and N-n-butyl (meth)acrylamide; N-vinylcarboxylic acid amides such as N-vinyl acetamide; Monomers having hydroxyl and amide groups, such as N-(2-hydroxyethyl)(meth)acrylamide, N-(2-hydroxypropyl)(meth)acrylamide, N-(1-hydroxypropyl)( Meth)acrylamide, N-(3-hydroxypropyl)(meth)acrylamide, N-(2-hydroxybutyl)(meth)acrylamide, N-(3-hydroxybutyl)(meth)acrylamide, N-hydroxyalkyl (meth)acrylamide, such as N-(4-hydroxybutyl)(meth)acrylamide; Monomers having an alkoxy group and an amide group, such as N-methoxymethyl (meth)acrylamide, N-methoxyethyl (meth)acrylamide, N-butoxymethyl (meth)acrylamide, etc., N-alkoxyalkyl ( Meth)acrylamide; In addition, N,N-dimethylaminopropyl (meth)acrylamide, N-(meth)acryloylmorpholine, etc.

Monomers having a nitrogen atom-containing ring: for example, N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpipe Razine, N-vinylpyrazine, N-vinylpyrrole, N-vinylimidazole, N-vinyloxazole, N-(meth)acryloyl-2-pyrrolidone, N-(meth)acryloylpiperidine , N-(meth)acryloylpyrrolidine, N-vinylmorpholine, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, N-vinyl-1,3-oxazine-2- ion, N-vinyl-3,5-morpholinedione, N-vinylpyrazole, N-vinylisoxazole, N-vinylthiazole, N-vinylisothiazole, N-vinylpyridazine, etc. (e.g., Lactams such as N-vinyl-2-caprolactam).

Monomers with a succinimide backbone: for example, N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryl Royl-8-oxyhexamethylenesuccinimide, etc.

Maleimides: For example, N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, N-phenylmaleimide, etc.

Itaconimides: For example, N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide Mead, N-cyclohexyl itaconimide, N-lauryl itaconimide, etc.

Aminoalkyl (meth)acrylate: For example, aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, (meth)acrylic acid t- Butylaminoethyl.

Monomers containing alkoxy groups: for example, 2-methoxyethyl (meth)acrylate, 3-methoxypropyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, (meth)acrylate. alkoxyalkyl (meth)acrylates such as butoxyethyl acrylate and ethoxypropyl (meth)acrylate; Alkoxyalkylene glycols (meth)acrylate, such as methoxyethylene glycol (meth)acrylate and methoxypolypropylene glycol (meth)acrylate.

Vinyl esters: For example, vinyl acetate, vinyl propionate, etc.

Vinyl ethers: For example, vinyl alkyl ethers such as methyl vinyl ether and ethyl vinyl ether.

Aromatic vinyl compounds: such as styrene, α-methylstyrene, vinyltoluene, etc.

Olefins: For example, ethylene, butadiene, isoprene, isobutylene, etc.

(meth)acrylic acid ester having an alicyclic hydrocarbon group: for example, cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, etc.

(meth)acrylic acid ester having an aromatic hydrocarbon group: for example, phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, etc.

In addition, (meth)acrylates containing heterocycles such as tetrahydrofurfuryl (meth)acrylate, (meth)acrylates containing halogen atoms such as (meth)acrylates containing vinyl chloride or fluorine atoms, and silicone (meth)acrylates. (meth)acrylate containing silicon atoms, (meth)acrylic acid ester obtained from terpene compound derivative alcohol, etc.

When using such a copolymerizable monomer, the amount used is not particularly limited, but is usually appropriate to be 0.01% by weight or more of the total amount of monomer components. From the viewpoint of better demonstrating the effect of the use of the copolymerizable monomer, the amount of the copolymerizable monomer may be 0.1% by weight or more, or 1% by weight or more, of the total amount of monomer components. Additionally, the amount of copolymerizable monomer used can be 50% by weight or less of the total amount of monomer components, and is preferably 40% by weight or less. As a result, the cohesive force of the adhesive can be prevented from becoming too high and the tack feeling at room temperature (25°C) can be improved.

In some embodiments, the acrylic polymer contains, as a monomer unit, N-vinyl cyclic amide represented by the following general formula (M1) and a hydroxyl group-containing monomer (a monomer having a hydroxyl group and another functional group, for example, a monomer containing a hydroxyl group and an amide group) It is preferable to contain at least one monomer selected from the group consisting of:

Here, R ¹ in the general formula (M1) is a divalent organic group.

By using N-vinyl cyclic amide, the cohesive force and polarity of the adhesive can be adjusted and the adhesive strength after heating can be improved. Specific examples of N-vinyl cyclic amides include N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-3-morpholinone, N-vinyl-2-caprolactam, and N-vinyl-2-caprolactam. -1,3-oxazin-2-one, N-vinyl-3,5-morpholinedione, etc. are mentioned. Particularly preferred are N-vinyl-2-pyrrolidone and N-vinyl-2-caprolactam.

The amount of N-vinyl cyclic amide used is not particularly limited, but is usually 0.01% by weight or more (preferably 0.1% by weight or more, for example, 0.5% by weight or more) of the total amount of monomer components for preparing an acrylic polymer. do. In some embodiments, the amount of N-vinyl cyclic amide used may be 1% by weight or more, 5% by weight or more, or 10% by weight or more of the total amount of the monomer component. In addition, from the viewpoint of improving tackiness at room temperature (25°C) and improving flexibility at low temperatures, the amount of N-vinyl cyclic amide used is usually appropriate to be 40% by weight or less of the total amount of the monomer component, and 30% by weight. It may be % or less, and may be 20% by weight or less.

By using a hydroxyl-containing monomer, the cohesive force and polarity of the adhesive can be adjusted and the adhesive strength after heating can be improved. In addition, the hydroxyl group-containing monomer provides a reaction point with a crosslinking agent (for example, an isocyanate-based crosslinking agent) described later, and can increase the cohesion of the adhesive through the crosslinking reaction.

Examples of hydroxyl group-containing monomers include 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, N-(2-hydroxyethyl)(meth)acrylamide, etc. can be used appropriately. Among them, preferred examples include 2-hydroxyethyl acrylate (HEA), 4-hydroxybutyl acrylate (4HBA), and N-(2-hydroxyethyl)acrylamide (HEAA).

The amount of the hydroxyl-containing monomer used is not particularly limited, but is usually 0.01% by weight or more (preferably 0.1% by weight or more, for example, 0.5% by weight or more) of the total amount of monomer components for preparing an acrylic polymer. In some embodiments, the amount of the hydroxyl-containing monomer used may be 1% by weight or more, 5% by weight or more, or 10% by weight or more of the total amount of the monomer component. In addition, from the viewpoint of improving tackiness at room temperature (25°C) and improving flexibility at low temperatures, the amount of hydroxyl-containing monomer used is generally appropriate to be 40% by weight or less of the total amount of the monomer component, and 30% by weight or less. It may be 20% by weight or less, or 10% by weight or less, or 5% by weight or less.

In some embodiments, as the copolymerizable monomer, N-vinyl cyclic amide and a hydroxyl group-containing monomer can be used in combination. In this case, the total amount of N-vinyl cyclic amide and hydroxyl group-containing monomer can be, for example, 0.1% by weight or more of the total amount of monomer components for preparing an acrylic polymer, may be 1% by weight or more, or 5% by weight or more. It may be 10% by weight or more, 15% by weight or more, 20% by weight or more, or 25% by weight or more. In addition, the total amount of N-vinyl cyclic amide and hydroxyl group-containing monomer can be, for example, 50% by weight or less based on the total amount of monomer components, and is preferably 40% by weight or less.

The method of obtaining the acrylic polymer is not particularly limited, and various polymerization methods known as methods for synthesizing acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization, can be appropriately employed. . In some embodiments, a solution polymerization method may be preferably employed. The polymerization temperature when performing solution polymerization can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, etc., for example, about 20°C to 170°C (typically about 40°C to 140°C). You can do this.

The initiator used for polymerization can be appropriately selected from conventionally known thermal polymerization initiators, photopolymerization initiators, etc., depending on the polymerization method. The polymerization initiator can be used individually or in combination of two or more types.

As a thermal polymerization initiator, for example, an azo-based polymerization initiator (e.g., 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azo Bis(2-methyl propionic acid)dimethyl, 4,4'-azobis-4-cyanovaleric acid, azobisisovaleronitrile, 2,2'-azobis(2-amidinopropane)dihydrochloride, 2 ,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, 2, 2'-azobis(N,N'-dimethyleneisobutylamidine)dihydrochloride, etc.); persulfate such as potassium persulfate; peroxide-based polymerization initiators (e.g., dibenzoyl peroxide, t-butyl permaleate, lauroyl peroxide, etc.); Redox-based polymerization initiators, etc. can be mentioned. The amount of the thermal polymerization initiator used is not particularly limited, but for example, is within the range of 0.01 parts by weight to 5 parts by weight, preferably 0.05 parts by weight to 3 parts by weight, based on 100 parts by weight of the monomer component used in the preparation of the acrylic polymer. You can do this.

The photopolymerization initiator is not particularly limited, and examples include benzoin ether-based photopolymerization initiator, acetophenone-based photopolymerization initiator, α-ketol-based photopolymerization initiator, aromatic sulfonyl chloride-based photopolymerization initiator, photoactive oxime-based photopolymerization initiator, and benzoin-based photopolymerization initiator. Initiators, benzyl-based photopolymerization initiators, benzophenone-based photopolymerization initiators, ketal-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, etc. can be used. The amount of the photopolymerization initiator used is not particularly limited, but for example, it is within the range of 0.01 parts by weight to 5 parts by weight, preferably 0.05 parts by weight to 3 parts by weight, based on 100 parts by weight of the monomer component used in the preparation of the acrylic polymer. can do.

In some embodiments, the acrylic polymer is in the form of a partially polymerized product (acrylic polymer syrup) obtained by polymerizing a part of the monomer component by irradiating ultraviolet (UV) light to a mixture of the above-described monomer component and a polymerization initiator, and is used as an adhesive. It may be included in an adhesive composition for forming a layer. The pressure-sensitive adhesive composition containing this acrylic polymer syrup can be applied to a predetermined coated body, and polymerization can be completed by irradiating ultraviolet rays. In other words, the acrylic polymer syrup can be understood as a precursor of acrylic polymer. The adhesive layer disclosed herein can be formed, for example, using an adhesive composition containing the acrylic polymer syrup and polymer B.

(Polymer B)

Polymer B in the technology disclosed herein may be various polymers such as acrylic polymer, rubber polymer, polyester polymer, urethane polymer, polyether polymer, polyamide polymer, and fluorine polymer. From the viewpoint of polymerization reactivity and ease of control of Mw, an acrylic polymer can be preferably employed. In particular, when polymer A is an acrylic polymer, good compatibility with polymer A is easy to be obtained by using an acrylic polymer as polymer B. Good compatibility between polymer A and polymer B is desirable because it can contribute to reducing the initial adhesive force and improving the adhesive force after heating through improved mobility of polymer B in the adhesive layer.

Polymer B has the structural characteristic of having a side chain with an EG group at the terminal, that is, an EG side chain. Here, the EG group is,

EG1 group: a hydrocarbon group having 12 to 22 carbon atoms, which may be halogenated, and

EG2 group: Halogenated hydrocarbon group with 11 or less carbon atoms

It is selected from the group consisting of. Polymer B may have multiple types of side chains having different types of EG groups. The different types of EG groups may be two or more types of EG1 groups, two or more types of EG2 groups, or a combination of one or two or more types of EG1 groups and one or two or more types of EG2 groups.

The EG1 group and the EG2 group are both low polarity and low reactivity groups (typically, they do not have a functional group that crosslinks with the polymer A). Polymer B can contribute to suppressing the adhesive force in the initial stage of sticking to the adherend due to the low polarity and mobility of the EG group disposed at the end of the EG side chain. In addition, in the pressure-sensitive adhesive sheet disclosed herein, the pressure-sensitive adhesive layer contains a combination of polymer A and polymer B, so that the arrangement or distribution of EG side chains in the pressure-sensitive adhesive layer changes with heating or passage of time after attachment, thereby causing the adherend Adhesion can be increased.

The EG1 group may be aliphatic or may include a moiety having aromaticity. From the viewpoint of the mobility of the EG1 side chain (and, by extension, the mobility of the EG1 group), an aliphatic EG1 group is generally more advantageous. In the aliphatic EG1 group, the EG1 group may have an acyclic structure or may contain a cyclic structure such as a cycloalkyl ring. From the viewpoint of the mobility of the EG1 side chain, it is preferable that the EG1 group has an acyclic structure (i.e., a chain structure). The EG1 group may be saturated or unsaturated. From the viewpoint of the mobility of the EG1 side chain, it is generally advantageous for the EG1 group to be saturated. The EG1 group may be linear or branched.

The EG1 group may be a hydrocarbon group, or may be a hydrocarbon group with a structure in which at least one hydrogen atom in the hydrocarbon group is replaced with a halogen atom, that is, a halogenated hydrocarbon group. The halogen atom may be any of fluorine, chlorine, bromine, or iodine. Among these, fluorine, chlorine and bromine are preferable, fluorine and chlorine are more preferable, and fluorine is particularly preferable. Hydrocarbon groups halogenated with multiple types of halogen atoms, for example, fluorine and chlorine, may be used. The halogenation rate of the EG1 group can be selected from the range of 0% to 100%. Here, the halogenation rate refers to the ratio of the number of halogen atoms to the total number of hydrogen atoms and halogen atoms contained in the EG1 group. A halogenation rate of 0% means that the EG1 group is a hydrocarbon group that is not halogenated. A halogenation rate of 100% means that the EG1 group has a structure in which all hydrogen atoms are replaced with halogen atoms (for example, fluorine atoms). From the viewpoint of adhesion increase by heating and compatibility, in some embodiments, the halogenation rate of the EG1 group may be, for example, 70% or less, 50% or less, or 30% or less. In addition, the number of halogen atoms contained in the EG1 group may be, for example, 3 or less, 2 or less, or 1. In some embodiments, an EG1 group that does not contain a halogen atom may be preferably employed.

Specific examples of preferred EG1 groups include lauryl group, isolauryl group, tridecyl group, isotridecyl group, tetradecyl group, isotetradecyl group, pentadecyl group, isopentadecyl group, hexadecyl group, and isohexade. Alkyl groups such as syl group, heptadecyl group, isoheptadecyl group, stearyl group, isostearyl group, nonadecyl group, isononadecyl group, eicosyl group, isoeicosyl group, henicosyl group, and behenyl group, and these alkyl groups A halogenated alkyl group (may be a perhaloalkyl group) in which at least one of the hydrogen atoms included is substituted with a halogen atom such as a fluorine atom is included, but is not limited to these.

The number of carbon atoms in the EG1 group is 22 or less. According to the EG1 group with this number of carbon atoms, it is easy to achieve both initial low adhesiveness and an increase in adhesive strength due to heating or aging. When the EG1 group is a non-halogenated hydrocarbon group, the number of carbon atoms in the EG1 group may be 12, but is more preferably 14 or more or 16 or more.

The EG2 group may be aliphatic or may include a moiety having aromaticity. From the viewpoint of the mobility of the EG2 side chain (and, by extension, the mobility of the EG2 group), an aliphatic EG2 group is generally more advantageous. In the aliphatic EG2 group, the EG2 group may have an acyclic structure or may contain a cyclic structure such as a cycloalkyl ring. From the viewpoint of the mobility of the EG2 side chain, it is preferable that the EG2 group has an acyclic structure (i.e., a chain structure). The EG2 group may be saturated or unsaturated. From the viewpoint of the mobility of the EG2 side chain, it is generally advantageous for the EG2 group to be saturated. The EG2 group may be linear or branched.

The EG2 group is a halogenated hydrocarbon group with 11 or less carbon atoms, that is, a hydrocarbon group with a structure in which at least one hydrogen atom is replaced with a halogen atom. The halogen atom may be any of fluorine, chlorine, bromine, or iodine. Among these, fluorine, chlorine and bromine are preferable, fluorine and chlorine are more preferable, and fluorine is particularly preferable. Hydrocarbon groups halogenated with multiple types of halogen atoms, for example, fluorine and chlorine, may be used. The number of halogen atoms contained in the EG2 group may be one, preferably two or more, and may be three or more. From the viewpoint of suppressing initial stickiness, the halogenation rate of the EG2 group is preferably 10% or more, preferably 25% or more, and may be 50% or more. The halogenation rate of the EG2 group may be 100%, may be 85% or less, or may be 70% or less from the viewpoint of easily increasing the adhesive force after heating.

From the viewpoint of the mobility of the EG2 side chain, the number of carbon atoms in the EG2 group is usually preferably 2 or more, and more preferably 3 or more. The number of carbon atoms in the EG2 group may be 10 or less, 8 or less, or 6 or less. In some preferred forms, the EG2 group may be a straight-chain or branched halogenated hydrocarbon group having 2 to 6 carbon atoms. Specific examples of such EG2 groups include difluoroethyl group, trifluoroethyl group, perfluoroethyl group, monochloromonofluoroethyl group, chlorotrifluoroethyl group, difluoropropyl group, trifluoropropyl group, tetrafluoro group. Lopropyl group, perfluoropropyl group, difluorobutyl group, trifluorobutyl group, tetrafluorobutyl group, perfluorobutyl group, difluoropentyl group, trifluoropentyl group, tetrafluorophen These include, but are not limited to, ethyl group, perfluoropentyl group, difluorohexyl group, trifluorohexyl group, tetrafluorohexyl group, and perfluorohexyl group.

Monomer m1 is a compound having the above-described EG group and a polymerizable functional group in the molecule. The polymerizable functional group is preferably a functional group capable of radical polymerization, and specific examples include, but are not limited to, ethylenically unsaturated groups such as (meth)acryloyl group, vinyl group, and allyl group. From the viewpoint of availability of the material and polymerization reactivity, monomer m1 having a (meth)acryloyl group is particularly preferable. From the viewpoint of the mobility of polymer B, the number of polymerizable functional groups in monomer m1 is preferably one per molecule.

In some embodiments, as the monomer m1 for introducing an EG1 group into polymer B, a (meth)acrylate having an EG1 group at the ester terminal, that is, EG1 (meth)acrylate, can be preferably employed. Acrylates having any of the above-mentioned EG1 groups at the ester terminal and methacrylates having any of the above-mentioned EG1 groups at the ester terminal can be used. EG1 (meth)acrylate can be used individually or in combination of two or more types.

In some embodiments, as the monomer m1 for introducing the EG2 group into polymer B, a (meth)acrylate having an EG2 group at the ester terminal, that is, EG2 (meth)acrylate, can be preferably employed. Acrylates having any of the above-mentioned EG2 groups at the ester terminal and methacrylates having any of the above-mentioned EG2 groups at the ester terminal can be used. EG2 (meth)acrylate can be used individually or in combination of two or more types. EG1 (meth)acrylate and EG2 (meth)acrylate may be used in combination.

The content of monomer m1 in the monomer component forming polymer B may be, for example, 1% by weight or more, and usually 2% by weight or more is appropriate, and is preferably 5% by weight or more. As the content of monomer m1 increases, the effect of using the monomer m1 tends to be more effective. From this viewpoint, in some embodiments, the content of the monomer m1 may be 10% by weight or more, 15% by weight or more, 20% by weight or more, 25% by weight or more, or 30% by weight or more. , may be 35% by weight or more, may be 40% by weight or more, may be 45% by weight or more, may be 50% by weight or more, and may be more than 50% by weight. Polymer B may be formed from a monomer component containing one or two or more types of monomer m1. In some embodiments, the content of monomer m1 in the monomer component is suitably 90% by weight or less from the viewpoint of polymerization reactivity and compatibility, may be 80% by weight or less, may be 70% by weight or less, and may be 55% by weight or less. It may be % by weight or less, and may be 45 % by weight or less.

The monomer component forming polymer B may contain, in addition to monomer m1, another monomer copolymerizable with monomer m1. Hereinafter, such monomers are also referred to as “other monomers.”

As a suitable example of the other monomer, methyl methacrylate (MMA) may be mentioned. By including MMA in the monomer component forming polymer B, it becomes easier to control the mobility of polymer B. This can be advantageous from the viewpoint of suppressing the initial adhesive force and improving the adhesive force rise ratio. The ratio of MMA in the monomer component forming polymer B may be, for example, 5% by weight or more, 10% by weight or more, 20% by weight or more, 25% by weight or more, or 35% by weight or more. You can continue. In some embodiments, the proportion of MMA may be, for example, more than 40% by weight, more than 50% by weight, or more than 55% by weight. In addition, from the viewpoint of making it easy to appropriately exert the effect of using monomer m1, the ratio of MMA is usually suitable to be 98% by weight or less, and may be 95% by weight or less, or 90% by weight or less. From the viewpoint of increasing the mobility of polymer B, the ratio of MMA may be 85% by weight or less, 75% by weight or less, or 65% by weight or less.

Other suitable examples of the above-mentioned other monomers include (meth)acrylic acid C _4-11 alkyl ester (more preferably, (meth)acrylic acid C _4-9 alkyl ester). By using (meth)acrylic acid C _4-11 alkyl ester, effects such as improved compatibility with polymer A and improved adhesive strength after heating can be realized. From the viewpoint of making it easy to achieve this effect, the proportion of (meth)acrylic acid C _4-11 alkyl ester in the monomer component forming polymer B can be, for example, 2% by weight or more, and usually 5% by weight. % or more is appropriate, and may be 10% by weight or more, 15% by weight or more, 20% by weight or more, or 25% by weight or more. For the same reason, the proportion of (meth)acrylic acid C _4-11 alkyl ester in the monomer component may be, for example, 90% by weight or less, 80% by weight or less, 75% by weight or less, and 70% by weight or less. It may be % by weight or less, and may be 65 weight% or less. It is preferable to use at least one type of (meth)acrylic acid C _4-9 alkyl ester, and it is particularly preferable to use at least one type of methacrylic acid C _4-9 alkyl ester.

The technology disclosed herein is preferably used in combination with (meth)acrylic acid C _4-11 alkyl ester (more preferably, (meth)acrylic acid C _4-9 alkyl ester) and MMA as the other monomers. It can be implemented. By copolymerizing monomer m1, (meth)acrylic acid C _4-11 alkyl ester, and MMA, the mobility of polymer B in the adhesive layer can be appropriately adjusted. The total amount of (meth)acrylic acid C _4-11 alkyl ester and MMA can be, for example, 50% by weight or more in the total amount of monomer components forming polymer B. According to this aspect, it is easy to obtain an adhesive sheet in which the initial adhesive force is suppressed and the adhesive force increase ratio is high. From the viewpoint of obtaining a higher effect, the total amount of (meth)acrylic acid C _4-11 alkyl ester and MMA may be 60% by weight or more, 75% by weight or more, or 85% by weight of the total amount of monomer components forming polymer B. It may be % or more, may be 90% by weight or more, may be 95% by weight or more, and may be 98% by weight or more. Polymer B may be a copolymer composed of EG1 (meth)acrylate as monomer m1, (meth)acrylic acid C _4-11 alkyl ester, and MMA, or EG2 (meth)acrylate as monomer m1 and (meth)acrylic acid. A copolymer composed of C _4-11 alkyl ester and MMA may be used.

Other examples of the above-mentioned other monomers include cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl (meth)acrylate, and 1-adamantyl (meth)acrylate. ) Carboxyl group-containing monomers exemplified as monomers that can be used when polymer A is an acrylic polymer, (meth)acrylic acid ester having an alicyclic hydrocarbon group of 11 or less carbon atoms at the ester terminal, such as acrylate, and acid anhydride group-containing monomers. Monomers, hydroxyl group-containing monomers, epoxy group-containing monomers, cyano group-containing monomers, isocyanate group-containing monomers, amide group-containing monomers, monomers having a nitrogen atom-containing ring, monomers having a succinimide skeleton, maleimides, itaconimides, ( Aminoalkyl meth)acrylates, vinyl esters, vinyl ethers, olefins, (meth)acrylic acid esters having an aromatic hydrocarbon group, heterocyclic-containing (meth)acrylates, halogen atom-containing (meth)acrylates, terpene compound derivative alcohols (meth)acrylic acid ester obtained from, etc. can be mentioned.

As further examples of the other monomers that may be included in the monomer component forming polymer B, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene Oxyalkylene di(meth)acrylates such as glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate; A monomer having a polyoxyalkylene skeleton, for example, polyethylene glycol or polypropylene glycol, has a polymerizable functional group such as (meth)acryloyl group, vinyl group, or allyl group at one end of the polyoxyalkylene chain, and the other end Polymerizable polyoxyalkylene ethers having an ether structure (alkyl ether, aryl ether, arylalkyl ether, etc.) at the terminal; alkoxyalkyl (meth)acrylate such as methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, propoxyethyl (meth)acrylate, butoxyethyl (meth)acrylate, and ethoxypropyl (meth)acrylate; Salts such as alkali metal (meth)acrylic acid; Polyhydric (meth)acrylates such as trimethylolpropane tri(meth)acrylic acid ester; vinyl halogenated compounds such as vinylidene chloride and 2-chloroethyl (meth)acrylate; Monomers containing oxazoline groups such as 2-vinyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, and 2-isopropenyl-2-oxazoline; Aziridine group-containing monomers such as (meth)acryloyl aziridine and 2-aziridinyl ethyl (meth)acrylate; hydroxyl group-containing vinyl monomers such as (meth)acrylic acid-2-hydroxyethyl, (meth)acrylic acid-2-hydroxypropyl, and adducts of lactones and (meth)acrylic acid-2-hydroxyethyl; Fluorine-containing vinyl monomers such as fluorine-substituted (meth)acrylic acid alkyl esters; Reactive halogen-containing vinyl monomers such as 2-chloroethyl vinyl ether and vinyl monochloroacetate; Organosilicon-containing vinyl monomers such as vinyltrimethoxysilane, γ-(meth)acryloxypropyltrimethoxysilane, allyltrimethoxysilane, trimethoxysilylpropylallylamine, and 2-methoxyethoxytrimethoxysilane. ; Other macromonomers having a radically polymerizable vinyl group at the end of the monomer polymerized with a vinyl group; etc. can be mentioned.

In some embodiments, polymer B that does not contain a functional group that causes a crosslinking reaction with polymer A can be preferably used. In other words, it is preferable that polymer B is contained in the adhesive layer in a form that is not chemically bonded to polymer A. The adhesive layer containing polymer B in this form has good mobility of polymer B when heated, and is suitable for improving the adhesive strength increase ratio. The functional group that causes a crosslinking reaction with polymer A may differ depending on the type of functional group possessed by the polymer A, but may be, for example, an epoxy group, isocyanate group, carboxy group, alkoxysilyl group, amino group, etc.

When using the other monomers, the amount used is usually less than 20% by weight of the total monomer component forming polymer B, and may be 10% by weight or less, from the viewpoint of making it easier to balance the properties. It may be 5% by weight or less.

In some embodiments, the monomer component forming polymer B may include a monomer having a polyorganosiloxane skeleton (hereinafter also referred to as “monomer S1”) as the other monomer. The monomer S1 is not particularly limited, and any monomer containing a polyorganosiloxane skeleton can be used. Monomer S1, due to its low polarity derived from its structure, promotes the uneven distribution of polymer B on the surface of the adhesive layer in the adhesive sheet before use (before attachment to the adherend), and provides light peelability (low It can contribute advantageously because it exhibits adhesiveness. As monomer S1, one having a structure having a polymerizable reactive group at one end can be preferably used. According to polymer B, which has a composition of copolymerization of monomer m1 and monomer S1, polymer B is formed having a side chain (EG side chain) derived from monomer m1 and a side chain having a polyorganosiloxane skeleton derived from monomer S1. Polymer B of this structure has a low initial adhesive force and tends to have a high adhesive force after heating due to the mobility and ease of movement of the side chain.

As monomer S1, for example, a compound represented by the following general formula (1) or (2) can be used. More specifically, examples of single-end reactive silicone oils manufactured by Shin-Etsu Chemical Co., Ltd. include X-22-174ASX, X-22-2426, X-22-2475, and KF-2012. Monomer S1 can be used individually or in combination of two or more types.

Here, in the general formulas (1) and (2), R ³ is hydrogen or methyl, R ⁴ is a methyl group or a monovalent organic group, and m and n are integers of 0 or more.

The functional group equivalent weight of monomer S1 may be, for example, 300 g/mol or more, and usually 500 g/mol or more is appropriate. From the viewpoint of making it easy to exhibit the effect of suppressing initial adhesive force, it is preferably 700 g/mol or more, and is preferably 800 g/mol or more. It may be more than mol, or more than 850 g/mol, or more than 1500 g/mol, or more than 2000 g/mol, or more than 2500 g/mol. In addition, the functional group equivalent of monomer S1 may be, for example, less than 50000 g/mol, and usually less than 30000 g/mol is appropriate. From the viewpoint of increasing the adhesion strength due to heating or aging, the functional group equivalent weight of monomer S1 is preferably less than 15,000 g/mol, more preferably less than 10,000 g/mol, still more preferably less than 6,000 g/mol, and 5,000 g/mol. It is especially preferable that it is less than. If the functional group equivalent of monomer S1 is more than the above-mentioned lower limit and less than the upper limit, it is easy to adjust the compatibility (e.g., compatibility of polymer A) and mobility in the adhesive layer to an appropriate range, and the initial low adhesiveness and It becomes easier to realize an adhesive sheet that achieves a high level of strong adhesiveness after the adhesive strength is increased.

Here, “functional group equivalent” means the weight of the main skeleton (for example, polydimethylsiloxane) bonded to each functional group. Regarding the notation unit g/mol, it is converted to 1 mol of functional group. The functional group equivalent of monomer S1 can be calculated, for example, from the spectral intensity of ¹ H-NMR (proton NMR) based on nuclear magnetic resonance (NMR). Calculation of the functional group equivalent weight (g/mol) of monomer S1 based on the spectral intensity of 1 H-NMR is based on a general structural analysis method for ¹ H ^- NMR spectrum analysis, and if necessary, as described in Japanese Patent No. 5951153. This can be done by referring to .

In addition, when using two or more types of monomers with different functional group equivalents as monomer S1, the arithmetic mean value can be used as the functional group equivalent of monomer S1. That is, the functional group equivalent of monomer S1 containing n types of monomers (monomer S1 ₁ , monomer S1 ₂ ...monomer S1 _n ) with different functional group equivalents can be calculated by the following formula.

Equivalent _weight of functional group _of monomer _S1 (g/mol) = (equivalent weight of functional group of _{monomer S1 1} Blending amount of)/(Blending amount of monomer S1 ₁ +Blending amount of monomer S1 ₂ +...+Blending amount of monomer S1 _n )

The content of monomer S1 in the monomer component forming polymer B may be, for example, 0.1% by weight or more, 0.5% by weight or more, 1% by weight or more, 5% by weight or more, or 10% by weight. It may be more than 15% by weight, and may be 20% by weight or more. As the content of monomer S1 increases, the effect of using monomer S1 tends to be better exhibited. In addition, the content of the monomer S1 is preferably 60% by weight or less from the viewpoint of polymerization reactivity and compatibility, and may be 50% by weight or less, 40% by weight or less, or 30% by weight or less. . In some embodiments, the content of monomer S1 may be less than 25% by weight, less than 15% by weight, less than 10% by weight, less than 5% by weight, or less than 1% by weight. The adhesive sheet disclosed herein initially exhibits low adhesiveness because the monomer component forming polymer B contains monomer m1, even if the content of monomer S1 in the monomer component is reduced or even if monomer S1 is not used. , after which the adhesive strength can be greatly increased. The pressure-sensitive adhesive sheet in which the amount of monomer S1 used in this way is suppressed (or monomer S1 is not used) is suitable for, for example, applications in which the inclusion of siloxane is undesirable (for example, applications in the manufacture of electronic devices, etc.). can be hired.

The glass transition temperature (T _B ) of polymer B is preferably -20°C or higher, more preferably -15°C or higher, and may be -5°C or higher from the viewpoint of suppressing initial adhesive force and improving reworkability. In some embodiments, T _B may be 0°C or higher, 5°C or higher, 10°C or higher, 20°C or higher, 30°C or higher, 40°C or higher, or 50°C or higher. . Additionally, from the viewpoint of increasing the adhesion strength increase by heating or aging, T _B is preferably 140°C or lower, may be 120°C or lower, and may be 100°C or lower. In some embodiments, T _B may be, for example, 95°C or lower, 85°C or lower, or 75°C or lower. The pressure-sensitive adhesive sheet disclosed herein can also be suitably implemented using polymer B with a T _B of 60°C or lower. The glass transition temperature (T _B ) of polymer B, like the glass transition temperature of polymer A, is determined by the Fox equation. T _B can be adjusted by the composition of the monomer component forming polymer B.

From the viewpoint of making it easier to control the mobility of polymer B in the adhesive layer, the glass transition temperature (T _B ) of polymer B is preferably 10°C or more higher than the glass transition temperature ( _TA ) of polymer A. In other words, it is desirable to satisfy T _B -T _A ≥10°C. From the viewpoint of obtaining a higher effect, in some embodiments, T _B -T _A may be, for example, 20°C or higher, 30°C or higher, 40°C or higher, or 50°C or higher. The upper limit of T _B -T _A is not particularly limited, but from the viewpoint of compatibility etc., it is usually preferably 180°C or lower, and may be 160°C or lower, or 140°C or lower. In some embodiments, T _B -T _A may be 125°C or lower, and may be 110°C or lower.

Polymer B can be produced, for example, by polymerizing the above-mentioned monomers by known methods such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, and photopolymerization.

Mw of polymer B is not particularly limited and can be set so that an adhesive sheet with N2/N1 of 2 or more is realized. The Mw of polymer B may be, for example, 1000 or more, or 5000 or more. If the Mw of polymer B is too low, the increase in adhesive force may become insufficient. In some preferred forms, the Mw of polymer B may be, for example, 10,000 or more, 12,000 or more, 15,000 or more, 17,000 or more, or 20,000 or more. Furthermore, from the viewpoint of making it easy to suppress the initial adhesive force, the Mw of polymer B is usually suitably less than 300,000, preferably less than 200,000, and more preferably less than 150,000. From the viewpoint of increasing the adhesion strength, in some embodiments, the Mw of polymer B may be, for example, 120,000 or less, 100,000 or less, 50,000 or less, 40,000 or less, 30,000 or less, or 25,000 or less. It's okay. If the Mw of polymer B is within the range of certain upper and lower limits mentioned above, it is easy to adjust the compatibility and mobility of polymer B in the adhesive layer to an appropriate range, and good reworkability at the initial stage of sticking and strong adhesion after the increase in adhesive strength are maintained at a high level. It becomes easier to realize an adhesive sheet that is compatible with .

In order to adjust the molecular weight of polymer B, a chain transfer agent can be used as needed. Examples of chain transfer agents include compounds having a mercapto group such as octyl mercaptan, lauryl mercaptan, t-nonyl mercaptan, t-dodecyl mercaptan, mercaptoethanol, and α-thioglycerol; Thioglycolic acid, methyl thioglycolic acid, ethyl thioglycolic acid, propyl thioglycolic acid, butyl thioglycolic acid, t-butyl thioglycolic acid, 2-ethylhexyl thioglycolic acid, octyl thioglycolic acid, isooctyl thioglycolic acid, thioglycolic acid esters such as decyl thioglycolic acid, dodecyl thioglycolic acid, thioglycolic acid ester of ethylene glycol, thioglycolic acid ester of neopentyl glycol, and thioglycolic acid ester of pentaerythritol; α-methylstyrene dimer; etc. can be mentioned. Chain transfer agents can be used individually or in combination of two or more types.

The amount of chain transfer agent used is not particularly limited and can be set so that polymer B with the desired molecular weight is obtained. The amount of chain transfer agent used per 100 parts by weight of monomer can be, for example, 0.05 part by weight or more, may be 0.1 part by weight or more, and may be 0.2 part by weight or less, and may be 0.2 part by weight or less, and may be 0.2 part by weight or less. The amount used is usually 20 parts by weight or more, but may be 15 parts by weight or less, or 10 parts by weight or less. Depending on the amount of this chain transfer agent used, it is easy to obtain polymer B suitable for the realization of a pressure-sensitive adhesive sheet that initially has low adhesiveness and whose adhesive strength increases significantly when heated.

Although not particularly limited, the amount of polymer B used is usually 1 part by weight or more per 100 parts by weight of polymer A. From the viewpoint of improving reworkability, etc., the amount of polymer B used relative to 100 parts by weight of polymer A can be, for example, 2 parts by weight or more, preferably 2.5 parts by weight or more, and may be 5 parts by weight or more, 8 It may be more than 10 parts by weight, or more than 10 parts by weight, or more than 15 parts by weight. In addition, from the viewpoint of easily increasing the adhesive strength after heating, the amount of polymer B used relative to 100 parts by weight of polymer A is usually 100 parts by weight or less, preferably 80 parts by weight or less, and may be 60 parts by weight or less. It may be 50 parts by weight or less, 45 parts by weight or less, 35 parts by weight or less, and 30 parts by weight or less.

The pressure-sensitive adhesive layer may contain polymers other than Polymer A and Polymer B (optional polymers) as needed, within a range that does not significantly impair the performance of the pressure-sensitive adhesive sheet disclosed herein. Examples of such optional polymers include polymers formed from monomer components that include a monomer having a polyorganosiloxane backbone (monomer S1) and that do not contain monomer m1 (e.g., monomer S1 and a polymer that does not correspond to monomer m1). (meth)acrylic acid alkyl ester-containing copolymer); A polymer formed from a monomer component that does not contain monomer m1 and monomer S1 and contains 50% by weight or more of an alkyl (meth)acrylate ester that does not correspond to monomer m1; etc. are included, but are not limited to these. The amount of the optional polymer used is usually 20% by weight or less of the total polymer components contained in the adhesive layer, and may be 15% by weight or less, 10% by weight or less, 5% by weight or less, or 3% by weight. % or less may be sufficient, and 1 weight% or less may be sufficient. The adhesive layer may be substantially free of polymers other than Polymer A and Polymer B.

(Cross-linking agent)

A crosslinking agent may be used in the adhesive layer as needed for purposes such as adjusting cohesion or suppressing initial adhesive force. As a crosslinking agent, a known crosslinking agent in the field of adhesives can be used. Examples of crosslinking agents include epoxy-based crosslinking agents, isocyanate-based crosslinking agents, silicone-based crosslinking agents, oxazoline-based crosslinking agents, aziridine-based crosslinking agents, silane coupling agents, alkyl etherified melamine-based crosslinking agents, and metal chelate-based crosslinking agents. Other examples of crosslinking agents include monomers having two or more polymerizable functional groups in one molecule, that is, polyfunctional monomers. The crosslinking agent can be used individually or in combination of two or more types.

Examples of isocyanate-based crosslinking agents include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, and tetramethylxylyl. Examples include lene diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, polymethylene polyphenylisocyanate, and adducts of these with polyols such as trimethylolpropane. Alternatively, a compound having at least one isocyanate group and one or more unsaturated bonds in one molecule, specifically, 2-isocyanatoethyl (meth)acrylate, etc. can also be used as an isocyanate-based crosslinking agent. These can be used individually or in combination of two or more types.

As an epoxy-based crosslinking agent, bisphenol A, epichlorohydrin-type epoxy resin, ethylene glycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, and 1,6-hexanediol. Glycidyl ether, trimethylolpropane triglycidyl ether, diglycidylaniline, diamineglycidylamine, N,N,N',N'-tetraglycidyl-m-xylylenediamine and 1,3 -Bis(N,N-diglycidylaminomethyl)cyclohexane, etc. can be mentioned. These can be used individually or in combination of two or more types.

Examples of metal chelate compounds include aluminum, iron, tin, titanium, and nickel as metal components, and acetylene, methyl acetoacetate, and ethyl lactate as chelate components. These can be used individually or in combination of two or more types.

Examples of polyfunctional monomers include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, and neopentyl glycol di( Meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, ethylene glycol di(meth)acrylate, 1,6-hexane Dioldi(meth)acrylate, 1,12-dodecanedioldi(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl(meth)acrylate, vinyl (meth)acrylate, divinylbenzene, epoxy acrylate, polyester acrylate, urethane acrylate, butyldiol (meth)acrylate, hexyldiol di(meth)acrylate, etc. Among them, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and dipentaerythritol hexa(meth)acrylate can be used suitably.

From the viewpoint of achieving both initial low adhesiveness and strong adhesiveness after heating in a balanced manner, examples of crosslinking agents that can be preferably employed in the adhesive layer formed from a solvent-based adhesive composition or a water-dispersed adhesive composition include an isocyanate-based crosslinking agent, Examples include epoxy-based crosslinking agents and metal chelate-based crosslinking agents. In an adhesive layer formed from a photocurable (for example, ultraviolet curable) adhesive composition, a polyfunctional monomer can be preferably employed as a crosslinking agent. You may use a combination of a multifunctional monomer and another crosslinking agent.

When using a crosslinking agent other than a polyfunctional monomer, the amount used is not particularly limited as long as it exceeds 0 parts by weight based on 100 parts by weight of polymer A. The amount of crosslinking agent used can be, for example, 0.01 parts by weight or more, and is preferably 0.05 parts by weight or more, based on 100 parts by weight of polymer A. By increasing the amount of crosslinking agent used, the adhesive force at the initial stage of sticking is suppressed and the reworkability tends to improve. In some embodiments, the amount of the crosslinking agent used relative to 100 parts by weight of Polymer A may be 0.1 part by weight or more, 0.5 part by weight or more, or 1 part by weight or more. On the other hand, from the viewpoint of avoiding deterioration of tack due to excessive improvement of cohesion, it is appropriate that the amount of crosslinking agent used per 100 parts by weight of polymer A is usually 15 parts by weight or less, and may be 10 parts by weight or less, or 5 parts by weight. You can do it below. The fact that the amount of crosslinking agent used is not too large can also be advantageous from the viewpoint of making it easier to realize an adhesive sheet with a high adhesive force increase ratio.

The technology disclosed herein can be preferably implemented using at least an isocyanate-based crosslinking agent as a crosslinking agent. An isocyanate-based crosslinking agent may be used in combination with another crosslinking agent. From the viewpoint of making it easier to realize an adhesive sheet that has both good reworkability at the initial stage of sticking and strong adhesiveness after the adhesive strength increases, in some embodiments, the amount of the isocyanate-based crosslinking agent used per 100 parts by weight of Polymer A is, for example, 0.1 part by weight or more. It can be 5 parts by weight or less, 0.3 parts by weight or more and 4 parts by weight or less, or 0.5 parts by weight or more and 3 parts by weight or less.

Although not particularly limited, when an isocyanate-based crosslinking agent is used in a configuration in which the pressure-sensitive adhesive layer includes a hydroxyl group-containing monomer as a monomer unit (for example, a configuration in which the monomer component forming polymer A includes a hydroxyl group-containing monomer), The amount of the hydroxyl group-containing monomer used, W _{OH ,} relative to the amount of the isocyanate-based crosslinking agent used, W NCO, can be set to an amount that makes W _OH /W _NCO 2 or more on a weight basis. In this way, by increasing the amount of hydroxyl group-containing monomer used in the isocyanate-based crosslinking agent, a suitable crosslinking structure can be formed to significantly increase the adhesive strength after heating relative to the adhesive strength at the initial stage of application. In some embodiments, W _OH /W _NCO may be 3 or more, 5 or more, 10 or more, 20 or more, 30 or more, or 50 or more. The upper limit of W _OH /W _NCO is not particularly limited. W _OH /W _NCO may be, for example, 500 or less, 200 or less, or 100 or less.

In order to advance any of the above-mentioned crosslinking reactions more effectively, a crosslinking catalyst may be used. As a crosslinking catalyst, for example, a tin-based catalyst (particularly dioctyltin dilaurate) can be preferably used. The amount of the crosslinking catalyst used is not particularly limited, but can be, for example, approximately 0.0001 parts by weight to 1 part by weight based on 100 parts by weight of Polymer A.

When using a polyfunctional monomer as a crosslinking agent, the amount used varies depending on the molecular weight and number of functional groups of the polyfunctional monomer, but is usually in the range of about 0.01 parts by weight to 3.0 parts by weight based on 100 parts by weight of polymer A. It is appropriate to do so. In some embodiments, the amount of the polyfunctional monomer used may be, for example, 0.02 parts by weight or more, or 0.03 parts by weight or more, based on 100 parts by weight of Polymer A. By increasing the amount of polyfunctional monomer used, the adhesive force at the initial stage of sticking is suppressed and the reworkability tends to improve. On the other hand, from the viewpoint of avoiding deterioration of tack due to excessive improvement of cohesion, the amount of polyfunctional monomer used may be 2.0 parts by weight or less, 1.0 parts by weight or less, and 0.5 parts by weight or less per 100 parts by weight of polymer A. . The fact that the amount of polyfunctional monomer used is not too large can also be advantageous from the viewpoint of making it easier to realize an adhesive sheet with a high adhesive force increase ratio.

(Tackifying resin)

The adhesive layer may contain a tackifying resin as needed. The tackifying resin is not particularly limited, and includes, for example, rosin-based tackifying resin, terpene-based tackifying resin, phenolic-based tackifying resin, hydrocarbon-based tackifying resin, ketone-based tackifying resin, polyamide-based tackifying resin, Examples include epoxy-based tackifying resin and elastomer-based tackifying resin. Tackifying resin can be used individually or in combination of two or more types.

Rosin-based tackifying resins include, for example, unmodified rosin (raw rosin) such as gum rosin, wood rosin, and tall oil rosin, and modified rosin (raw rosin) obtained by modifying these unmodified rosins by polymerization, disproportionation, hydrogenation, etc. Polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, other chemically modified rosin, etc.) as well as various rosin derivatives.

As the rosin derivative, for example

Rosin phenolic resin obtained by adding phenol to rosins (unmodified rosin, modified rosin, various rosin derivatives, etc.) with an acid catalyst and thermally polymerizing them;

Rosin ester compounds (unmodified rosin esters) obtained by esterifying unmodified rosin with alcohol, or modified rosins such as polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, and partially hydrogenated rosin, can be mixed with alcohol. rosin ester-based resins such as ester compounds of modified rosin esterified by esterification (polymerized rosin ester, stabilized rosin ester, disproportionated rosin ester, fully hydrogenated rosin ester, partially hydrogenated rosin ester, etc.);

Unsaturated fatty acid-modified rosin-based resin obtained by modifying unmodified rosin or modified rosin (polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, etc.) with unsaturated fatty acid;

Unsaturated fatty acid-modified rosin ester-based resin obtained by modifying rosin ester-based resin with unsaturated fatty acid;

Reduction treatment of carboxyl groups in unmodified rosin, modified rosin (polymerized rosin, stabilized rosin, disproportionated rosin, fully hydrogenated rosin, partially hydrogenated rosin, etc.), unsaturated fatty acid-modified rosin-based resin, and unsaturated fatty acid-modified rosin ester-based resin. One rosin alcohol-based resin;

Metal salts of rosin-based resins (especially rosin ester-based resins), such as unmodified rosin, modified rosin, and various rosin derivatives, are included.

Terpene-based tackifying resins include, for example, terpene-based resins such as α-pinene polymer, β-pinene polymer, and dipentene polymer, and these terpene-based resins can be modified (phenol-modified, aromatic-modified, hydrogenated-modified, hydrocarbon-modified, etc.) ) and modified terpene-based resins (for example, terpene phenol-based resins, styrene-modified terpene-based resins, aromatic modified terpene-based resins, hydrogenated terpene-based resins, etc.).

Examples of phenol-based tackifying resins include condensates of various phenols (e.g., phenol, m-cresol, 3,5-xylenol, p-alkylphenol, resorcin, etc.) and formaldehyde (e.g. , alkylphenol-based resins, xylene-formaldehyde-based resins, etc.), resol obtained by addition reaction of the above-mentioned phenols and formaldehyde with an alkali catalyst, and novolak obtained by condensation reaction of the above-mentioned phenols and formaldehyde with an acid catalyst.

Examples of hydrocarbon tackifying resins include aliphatic hydrocarbon resins, aromatic hydrocarbon resins, aliphatic cyclic hydrocarbon resins, aliphatic and aromatic petroleum resins (styrene-olefin copolymers, etc.), aliphatic and alicyclic petroleum resins, and hydrogenated hydrocarbons. Various hydrocarbon-based resins such as resin, coumarone-based resin, and coumarone-indene-based resin can be mentioned.

Commercially available polymerized rosin esters that can be preferably used include those manufactured by Arakawa Chemical Industries, Ltd. under the brand names “Pencel D-125”, “Pencel D-135”, “Pencel D-160”, “Pencel KK”, and “Pencel”. C" etc. are exemplified, but are not limited to these.

Commercially available terpene phenol-based resins that can be preferably used include those manufactured by Yasuhara Chemical Co., Ltd. under the trade names “YS Polystar S-145,” “YS Polystar G-125,” “YS Polystar N125,” and “YS Polystar.” Examples include “Star U-115”, “Tamanol 803L” and “Tamanol 901” manufactured by Arakawa Kagaku Kogyo Co., Ltd., and “Smirite Resin PR-12603” manufactured by Sumitomo Bakelite Co., Ltd. It is not limited to these.

The content of the tackifying resin is not particularly limited, and can be set to achieve appropriate adhesive performance depending on the purpose or use. The content of the tackifying resin (when two or more types of tackifying resins are included, their total amount) relative to 100 parts by weight of polymer A can be, for example, about 5 to 500 parts by weight.

As a tackifying resin, one having a softening point (softening temperature) of approximately 80°C or higher (preferably approximately 100°C or higher, for example, approximately 120°C or higher) can be preferably used. According to the tackifying resin having a softening point equal to or higher than the above-described lower limit, a pressure-sensitive adhesive sheet satisfying N ₈₀ /N ₅₀ ≥ 5 can be easily obtained. The upper limit of the softening point is not particularly limited, and may be, for example, approximately 200°C or lower (typically 180°C or lower). In addition, the softening point of the tackifying resin can be measured based on the softening point test method (circle and ball method) specified in JIS K2207.

In addition, the adhesive layer in the technology disclosed herein may contain a leveling agent, plasticizer, softener, colorant (dye, pigment, etc.), filler, antistatic agent, and anti-aging agent to the extent that the effect of the present invention is not significantly impaired. Known additives that can be used in adhesives, such as ultraviolet absorbers, antioxidants, light stabilizers, and preservatives, may be included as needed.

The pressure-sensitive adhesive layer constituting the pressure-sensitive adhesive sheet disclosed herein may be a cured layer of the pressure-sensitive adhesive composition. That is, the adhesive layer can be formed by applying (for example, applying) a water-dispersible, solvent-based, photocurable, or hot-melt adhesive composition to an appropriate surface and then appropriately curing the adhesive composition. When two or more types of curing treatments (drying, crosslinking, polymerization, cooling, etc.) are performed, they can be performed simultaneously or in multiple steps. In an adhesive composition using a partially polymerized product (acrylic polymer syrup) of a monomer component, a final copolymerization reaction is typically performed as the curing treatment. That is, the partially polymerized product is subjected to a further copolymerization reaction to form a fully polymerized product. For example, if it is a photocurable adhesive composition, light irradiation is performed. If necessary, curing treatment such as crosslinking or drying may be performed. For example, when it is necessary to dry with a photocurable adhesive composition, photocuring may be performed after drying. In the adhesive composition using a fully polymerized product, drying (heat drying), crosslinking, etc. are typically performed as the curing treatment, if necessary.

Application of the adhesive composition can be performed using a common coater such as a gravure roll coater, reverse roll coater, kiss roll coater, dip roll coater, bar coater, knife coater, or spray coater.

The thickness of the adhesive layer is not particularly limited, and can be, for example, 1 μm or more. In some embodiments, the thickness of the adhesive layer may be, for example, 3 μm or more, 5 μm or more, 8 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, or 20 μm or more. It may be excess. As the thickness of the adhesive layer increases, the adhesive force tends to increase after heating. Additionally, in some embodiments, the thickness of the adhesive layer may be, for example, 300 μm or less, 200 μm or less, 150 μm or less, 100 μm or less, 70 μm or less, or 50 μm or less. It may be 40㎛ or less. The fact that the thickness of the adhesive layer is not too large can be advantageous from the viewpoint of reducing the thickness of the adhesive sheet and preventing cohesive failure of the adhesive layer. Additionally, in the case of a pressure-sensitive adhesive sheet having a first pressure-sensitive adhesive layer and a second pressure-sensitive adhesive layer on the first and second sides of the substrate, the thickness of the pressure-sensitive adhesive layer described above can be applied to at least the thickness of the first pressure-sensitive adhesive layer. The thickness of the second adhesive layer can also be selected from the same range. Additionally, in the case of an inorganic adhesive sheet, the thickness of the adhesive sheet matches the thickness of the adhesive layer.

Although not particularly limited, the gel fraction of the adhesive constituting the adhesive layer is usually suitably in the range of 20.0% to 99.0%, and preferably in the range of 30.0% to 90.0%. By setting the gel fraction within the above range, it becomes easy to realize an adhesive sheet that achieves both high levels of reworkability at the initial stage of application and strong adhesion after the adhesive strength increases. The gel fraction is measured by the following method.

[Measurement of gel fraction]

Approximately 0.1 g of an adhesive sample (weight Wg ₁ ) is wrapped in a pouch-like porous polytetrafluoroethylene film (weight Wg ₂ ) with an average pore diameter of 0.2 µm, and the entrance is tied with a yarn (weight Wg ₃ ). As the porous polytetrafluoroethylene membrane, product name “Nitoflon (registered trademark) NTF1122” (Nitto Denko Co., Ltd., average pore diameter 0.2 μm, porosity 75%, thickness 85 μm) or its equivalent product is used. This package is immersed in 50 mL of ethyl acetate and kept at room temperature (typically 23°C) for 7 days to elute the sol content (ethyl acetate soluble content) in the adhesive out of the membrane. Next, the package is taken out, the ethyl acetate adhering to the outer surface is wiped off, the package is dried at 130°C for 2 hours, and the weight (Wg ₄ ) of the package is measured. By substituting each value into the equation below, the gel fraction G _C of the adhesive can be calculated.

Gel fraction G _C (%)=[(Wg ₄ -Wg ₂ -Wg ₃ )/Wg ₁ ]×100

<Supporting description>

The pressure-sensitive adhesive sheet in some forms may be in the form of a pressure-sensitive adhesive sheet with a base material having a pressure-sensitive adhesive layer on one or both sides of a support base material. The material of the support base material is not particularly limited and can be appropriately selected depending on the purpose of use or usage mode of the adhesive sheet. Non-limiting examples of substrates that can be used include polyolefin films whose main components are polyolefins such as polypropylene and ethylene-propylene copolymers, polyester films whose main components are polyesters such as polyethylene terephthalate and polybutylene terephthalate, and polyester films. Plastic films such as polyvinyl chloride films containing vinyl chloride as a main component; Foam sheets containing foams such as polyurethane foam, polyethylene foam, and polychloroprene foam; Woven fabrics and non-woven fabrics made by spinning alone or in a blend of various fibrous materials (which may be natural fibers such as hemp and cotton, synthetic fibers such as polyester and vinylon, and semi-synthetic fibers such as acetate); Paper such as Japanese paper, fine paper, kraft paper, and crepe paper; Metal foil such as aluminum foil and copper foil; etc. can be mentioned. It may be a base material composed of a combination of these. Examples of such composite substrates include, for example, a substrate having a structure in which metal foil and the above plastic film are laminated, a plastic substrate reinforced with inorganic fibers such as glass cloth, etc.

As a base material for the adhesive sheet disclosed herein, various film base materials can be preferably used. The film substrate may be a porous substrate such as a foam film or a non-woven fabric sheet, may be a non-porous substrate, or may be a substrate having a structure in which a porous layer and a non-porous layer are laminated. In some embodiments, the film substrate may preferably include a resin film capable of independently maintaining its shape (self-supporting or non-dependent) as a base film. Here, “resin film” means a resin film that has a non-porous structure and typically contains substantially no air bubbles (voidless). Therefore, the resin film is a concept that is distinct from foam films or nonwoven fabrics. As the resin film, one that can independently maintain its shape (self-supporting or non-dependent) can be preferably used. The resin film may have a single-layer structure or a multi-layer structure of two or more layers (for example, a three-layer structure).

Resin materials constituting the resin film include, for example, polyester, polyolefin, nylon 6, nylon 66, partially aromatic polyamide, etc., polyamide (PA), polyimide (PI), polyamideimide (PAI), and polyether. Etherketone (PEEK), polyethersulfone (PES), polyphenylene sulfide (PPS), polycarbonate (PC), polyurethane (PU), ethylene-vinyl acetate copolymer (EVA), polytetrafluoroethylene Resins such as fluororesin (PTFE), acrylic resin, polyacrylate, polystyrene, polyvinyl chloride, and polyvinylidene chloride can be used. The resin film may be formed using a resin material containing one type of such resin alone, or may be formed using a resin material blended of two or more types. The resin film may be unstretched or stretched (for example, uniaxially stretched or biaxially stretched).

Suitable examples of the resin material constituting the resin film include polyester resin, PPS resin, and polyolefin resin. Here, polyester-based resin refers to a resin containing polyester in a proportion exceeding 50% by weight. Likewise, PPS resin refers to a resin containing PPS in a proportion exceeding 50% by weight, and polyolefin-based resin refers to a resin containing polyolefin in a proportion exceeding 50% by weight.

As the polyester resin, a polyester resin containing as a main component a polyester obtained by polycondensing a dicarboxylic acid and a diol is typically used. Specific examples of polyester resins include polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), and polybutylene naphthalate.

As the polyolefin resin, one type of polyolefin can be used alone or two or more types of polyolefin can be used in combination. The polyolefin may be, for example, a homopolymer of α-olefin, a copolymer of two or more types of α-olefin, or a copolymer of one or two or more types of α-olefin and another vinyl monomer. Specific examples include ethylene-propylene copolymers such as polyethylene (PE), polypropylene (PP), poly-1-butene, poly-4-methyl-1-pentene, and ethylene propylene rubber (EPR), and ethylene-propylene-butene copolymers. Polymers, ethylene-butene copolymers, ethylene-vinyl alcohol copolymers, ethylene-ethyl acrylate copolymers, etc. may be mentioned. Both low density (LD) polyolefin and high density (HD) polyolefin can be used. Examples of polyolefin resin films include non-oriented polypropylene (CPP) film, biaxially oriented polypropylene (OPP) film, low-density polyethylene (LDPE) film, linear low-density polyethylene (LLDPE) film, medium-density polyethylene (MDPE) film, and high-density polyethylene (MDPE) film. Examples include polyethylene (HDPE) film, polyethylene (PE) film blended with two or more types of polyethylene (PE), and PP/PE blend film blended with polypropylene (PP) and polyethylene (PE).

Specific examples of resin films that can be preferably used as the base film of the adhesive sheet disclosed herein include PET film, PEN film, PPS film, PEEK film, CPP film, and OPP film. Examples of preferred base films from the viewpoint of strength and dimensional stability include PET film, PEN film, PPS film, and PEEK film. PET film and PPS film are particularly preferable from the viewpoint of ease of availability of the substrate, and among them, PET film is preferable.

The resin film needs to contain known additives such as light stabilizers, antioxidants, antistatic agents, colorants (dyes, pigments, etc.), fillers, slip agents, and anti-blocking agents, to the extent that the effects of the present invention are not significantly impaired. It can be mixed according to. The amount of additives is not particularly limited and can be set appropriately depending on the purpose of the adhesive sheet.

The manufacturing method of the resin film is not particularly limited. For example, conventionally known general resin film molding methods such as extrusion molding, inflation molding, T die cast molding, and calender roll molding can be appropriately employed.

The substrate may be substantially composed of such a base film. Alternatively, the substrate may include an auxiliary layer in addition to the base film. Examples of the auxiliary layer include an optical property adjustment layer (e.g., a colored layer, an anti-reflection layer), a surface treatment layer such as a printing layer, a laminate layer, an antistatic layer, an undercoating layer, and a peeling layer for giving the substrate a desired appearance. I can hear it.

The thickness of the base material is not particularly limited and can be selected depending on the purpose of use or usage mode of the adhesive sheet. The thickness of the substrate may be, for example, 1000 μm or less. In some embodiments, from the viewpoint of handling and processability of the adhesive sheet, the thickness of the base material may be, for example, 500 μm or less, 300 μm or less, 250 μm or less, or 200 μm or less. From the viewpoint of miniaturization and weight reduction of products to which the adhesive sheet is applied, in some embodiments, the thickness of the substrate may be, for example, 160 μm or less, 130 μm or less, 100 μm or less, or 90 μm or less. , may be 70㎛ or less, may be 50㎛ or less, may be 25㎛ or less, may be 10㎛ or less, and may be 5㎛ or less. As the thickness of the substrate becomes thinner, the flexibility of the adhesive sheet and its ability to follow the surface shape of the adherend tend to improve. In addition, from the viewpoint of handling, processability, etc., the thickness of the substrate may be, for example, 2 μm or more, 5 μm or more, 10 μm or more, 20 μm or more, 25 μm or more, or more than 25 μm. It's okay. In some embodiments, the thickness of the substrate may be, for example, 30 μm or more, 35 μm or more, 55 μm or more, 75 μm or more, or 120 μm or more. For example, in an adhesive sheet that can be used for purposes such as reinforcing, supporting, and relieving impacts of an adherend, a substrate with a thickness of 30 μm or more can be preferably used.

If necessary, the first surface of the substrate is subjected to a conventionally known surface treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, or formation of an undercoat layer by application of an undercoating agent (primer). It may be implemented. This surface treatment may be a treatment to improve the anchoring properties of the adhesive layer to the substrate. For example, in an adhesive sheet provided with a base material containing a resin film as a base film, a base material to which such anchoring performance improvement treatment has been performed can be preferably employed. The above surface treatments can be applied individually or in combination. The composition of the primer used to form the undercoat layer is not particularly limited and can be appropriately selected from known ones. The thickness of the undercoating layer is not particularly limited, but is usually about 0.01 μm to 1 μm, and is preferably about 0.1 μm to 1 μm. Other treatments that can be performed on the first side of the substrate as needed include antistatic layer formation treatment, colored layer formation treatment, printing treatment, and the like.

When the adhesive sheet disclosed herein is in the form of a single-sided adhesive sheet having an adhesive layer only on the first side of the substrate, the second side of the substrate is treated with a conventionally known surface treatment, such as peeling treatment or antistatic treatment, if necessary. may be implemented. For example, by surface treating the back of the substrate with a release treatment agent (typically by providing a release layer with a release treatment agent), the rewinding force of the adhesive sheet wound into a roll can be lightened. As the peeling treatment agent, a silicone-based peeling treatment agent, a long-chain alkyl-based peeling treatment agent, an olefin-based peeling treatment agent, a fluorine-based peeling treatment agent, a fatty acid amide-based peeling treatment agent, molybdenum sulfide, silica powder, etc. can be used. Additionally, for the purposes of improving printability, reducing light reflectivity, improving layering properties, etc., the second side of the substrate may be subjected to treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, or alkali treatment. In addition, in the case of a double-sided adhesive sheet, the second side of the substrate may be subjected to a surface treatment similar to that exemplified above as the surface treatment that can be applied to the first side of the substrate, if necessary. In addition, the surface treatment performed on the first side of the substrate and the surface treatment performed on the second side may be the same or different.

<Adhesive sheet>

(Characteristics of adhesive sheets, etc.)

The adhesive sheet disclosed herein has a ratio of adhesive force N2 (adhesive force after heating) to adhesive force N1 (initial adhesive force), that is, N2/N1 (adhesion increase ratio) of 2 or more, so that it can exhibit good reworkability in the initial stage of sticking. In addition, the adhesive strength can be greatly increased by subsequent heating, etc. From the viewpoint of achieving both reworkability and strong adhesion during use at a higher level, N2/N1 is preferably 3 or more, and more preferably 4 or more. In some embodiments, N2/N1 of the adhesive sheet may be 5 or more, 7 or more, 10 or more, 12 or more, or 15 or more. The upper limit of N2/N1 is not particularly limited. From the viewpoint of ease of manufacturing and economic efficiency of the adhesive sheet, in some embodiments, N2/N1 may be, for example, 80 or less, 60 or less, 45 or less, 35 or less, or 25 or less.

Here, the adhesive force N1 [N/25mm] is the condition of a peeling angle of 180 degrees and a tensile speed of 300 mm/min after being pressed to a stainless steel (SUS) plate as an adherend and left for 30 minutes in an environment of 23°C and 50% RH. This is determined by measuring the 180° peel adhesion. The adhesive force N2 [N/25mm] is obtained by pressing a SUS plate as an adherend, heating it at 80°C for 5 minutes, and then leaving it in an environment of 23°C and 50% RH for 30 minutes, with a peeling angle of 180 degrees and a tensile speed of 300mm/. This is determined by measuring the 180° peel adhesion under the conditions of As the adherend, SUS304BA board is used in both measurements of adhesive force N1 and N2. In the measurement, if necessary, the adhesive sheet of the measurement object can be reinforced by attaching an appropriate backing material (for example, a PET film with a thickness of about 25 μm). More specifically, the adhesive forces N1 and N2 can be measured according to the method described in the Examples described later.

Although not particularly limited, the adhesive force N1 (initial adhesive force) is usually suitably 10 N/25 mm or less, and is preferably less than 10 N/25 mm. From the viewpoint of improving reworkability, etc., in some embodiments, the adhesive force N1 is preferably less than 8 N/25 mm, may be less than 7 N/25 mm, may be less than 5 N/25 mm, or may be less than 3 N/25 mm. The lower limit of the initial adhesive force is not particularly limited, and may be, for example, 0.01 N/25 mm or more. From the viewpoint of adhesion workability to the adherend and prevention of misalignment before the adhesion increases, the adhesion N1 is generally appropriate to be 0.1 N/25 mm or more, and is preferably 0.3 N/25 mm or more. From the viewpoint of making it easier to obtain higher adhesive strength after heating, in some embodiments, the initial adhesive strength may be, for example, 0.5 N/25 mm or more, 0.7 N/25 mm or more, 1 N/25 mm or more, or 1.2 N/25 mm or more. It may be 25mm or more.

The adhesive force N2 (adhesive force after heating) is not particularly limited as long as it is twice or more than the initial adhesive force. From the viewpoint of increasing the bonding reliability by the adhesive sheet disclosed herein, the adhesive force after heating is generally preferably 3N/25mm or more, more preferably 4N/25mm or more, may be 5N/25mm or more, and may be 7N/25mm or more. It may be 10N/25mm or more, 15N/25mm or more, or 20N/25mm or more. The upper limit of adhesive strength after heating is not particularly limited. From the viewpoint of facilitating compatibility with good rework performance in the initial stage of sticking, in some embodiments, the adhesive force after heating may be, for example, 70 N/25 mm or less, 60 N/25 mm or less, or 50 N/25 mm or less. do.

In addition, in this specification, the adhesive strength after heating of the adhesive sheet represents a characteristic of the adhesive sheet and does not limit the mode of use of the adhesive sheet. In other words, the mode of use of the adhesive sheet disclosed herein is not limited to the mode of heating at 80°C for 5 minutes, for example, in the room temperature range (usually 20°C to 30°C, typically 23°C to 25°C). It can also be used in a form that does not specifically perform heating treatment above ℃). Even in this mode of use, adhesion increases over a long period of time and a strong bond can be realized. In addition, the adhesive sheet disclosed herein can promote an increase in adhesive strength by heat treatment at any timing after sticking. The heating temperature in this heat treatment is not particularly limited and can be set in consideration of workability, economic efficiency, heat resistance of the base material of the adhesive sheet and the adherend, etc. The heating temperature may be, for example, less than 150°C, less than 120°C, less than 100°C, less than 80°C, or less than 70°C. In addition, the heating temperature can be, for example, 35°C or higher, may be 50°C or higher, may be 60°C or higher, may be 80°C or higher, or may be 100°C or higher. According to a higher heating temperature, the adhesive force can be increased by a shorter treatment time. The heating time is not particularly limited, and may be, for example, 1 hour or less, 30 minutes or less, 10 minutes or less, or 5 minutes or less. Alternatively, heat treatment may be performed for a longer period of time as long as no significant thermal deterioration occurs in the adhesive sheet or adherend. In addition, the heat treatment may be performed at once, or may be performed divided into multiple times.

(Adhesive sheet with base material)

When the adhesive sheet disclosed herein is in the form of an adhesive sheet with a base material, the thickness of the adhesive sheet may be, for example, 1000 μm or less, 600 μm or less, 350 μm or less, or 250 μm or less. From the viewpoint of miniaturization, weight reduction, and thinning of products to which the adhesive sheet is applied, in some embodiments, the thickness of the adhesive sheet may be, for example, 200 μm or less, 175 μm or less, 140 μm or less, or 120 μm or less. It may be ㎛ or less, and may be 100 ㎛ or less (for example, less than 100 ㎛). In addition, the thickness of the adhesive sheet may be, for example, 5 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 25 μm or more, or 30 μm from the viewpoint of handling, etc. It can be more than that. In some embodiments, the thickness of the adhesive sheet may be, for example, 50 μm or more, 60 μm or more, 80 μm or more, 100 μm or more, or 130 μm or more. The upper limit of the thickness of the adhesive sheet is not particularly limited.

In addition, the thickness of the adhesive sheet refers to the thickness of the portion attached to the adherend. For example, in the adhesive sheet 1 of the configuration shown in FIG. 1, the thickness refers to the thickness from the adhesive surface 21A of the adhesive sheet 1 to the second surface 10B of the base material 10, and the release liner 31 ) does not include the thickness.

The adhesive sheet disclosed herein can be suitably implemented, for example, in an embodiment in which the thickness Ts of the support substrate is greater than the thickness Ta of the adhesive layer, that is, in an embodiment in which Ts/Ta is greater than 1. Although not particularly limited, Ts/Ta may be, for example, 1.1 or more, 1.2 or more, 1.5 or more, or 1.7 or more. For example, in adhesive sheets that can be used for purposes such as reinforcing, supporting, and relieving impacts of an adherend, an increase in Ts/Ta tends to make it easier to achieve a good effect even if the adhesive sheet is made thinner. In some embodiments, Ts/Ta may be 2 or more (for example, greater than 2), 3 or more, or 4 or more. Additionally, Ts/Ta can be, for example, 50 or less, and may be 20 or less. From the viewpoint of making it easier to exhibit adhesive force after high heating even if the adhesive sheet is thinned, Ts/Ta may be, for example, 10 or less or 8 or less.

The adhesive layer is preferably adhered to the support substrate. The above-mentioned adhesion means that, in the case of a pressure-sensitive adhesive sheet whose adhesive strength has increased after sticking to an adherend, the pressure-sensitive adhesive layer is attached to the support substrate to the extent that peeling does not occur at the interface between the pressure-sensitive adhesive layer and the support substrate when the pressure-sensitive adhesive sheet is peeled from the adherend. This means that it exhibits sufficient anchoring properties. According to the adhesive sheet with a base material in which the adhesive layer is fixed to the support base material, the adherend and the support base material can be firmly integrated. As a result, for example, functions such as reinforcing, supporting, and relieving impacts of the adherend can be effectively exercised. As a suitable example of a pressure-sensitive adhesive sheet in which an adhesive layer is fixed to a substrate, after sticking to an adherend, the pressure is at least 3N/25mm, preferably 5N/25mm or more, more preferably 10N/25mm or more, for example, 15N/25mm or more. When peeling from the adherend while developing an adhesive force of 25 mm or more (180° peel adhesive force measured under the conditions of a peel angle of 180 degrees and a tensile speed of 300 mm/min), peeling (anchoring failure) occurs between the adhesive layer and the support substrate. Examples include pressure-sensitive adhesive sheets that do not generate heat. An adhesive sheet that has an adhesive force of 3 N/25 mm or more after heating and does not cause anchoring failure when measuring the adhesive force after heating is a suitable example corresponding to an adhesive sheet in which an adhesive layer is fixed to a base material.

The pressure-sensitive adhesive sheet disclosed herein includes, for example, contacting a liquid pressure-sensitive adhesive composition with the first side of a substrate, and curing the pressure-sensitive adhesive composition on the first side to form a pressure-sensitive adhesive layer in this order. It can be preferably manufactured by. Curing of the adhesive composition may involve one or more steps such as drying, crosslinking, polymerization, and cooling of the adhesive composition. According to the method of forming a pressure-sensitive adhesive layer by curing a liquid pressure-sensitive adhesive composition on the first side of a substrate, the cured pressure-sensitive adhesive layer is bonded to the first side of the substrate, thereby disposing the pressure-sensitive adhesive layer on the first side. In comparison, the anchoring property of the adhesive layer to the substrate can be improved. Using this, an adhesive sheet in which an adhesive layer is fixed to a base material can be suitably manufactured.

In some embodiments, as a method of contacting the first surface of the substrate with the liquid adhesive composition, a method of directly applying the adhesive composition to the first surface of the substrate may be employed. By bringing the first side (adhesive side) of the adhesive layer cured on the first side of the substrate into contact with the peeling surface, the second side of the adhesive layer is adhered to the first side of the substrate, and the first side of the adhesive layer is also adhered to the first side of the adhesive layer. An adhesive sheet with a surface in contact with a peeling surface can be obtained. As the peeling surface, the surface of a peeling liner, the back of a peeling-treated base material, etc. can be used.

In addition, for example, in the case of a photocurable adhesive composition using a partial polymerization (acrylic polymer syrup) of a monomer component, for example, after applying the adhesive composition to the peeling surface, the applied adhesive composition is applied to the first side of the base material. By covering, the uncured adhesive composition may be brought into contact with the first surface of the substrate, and in that state, the adhesive composition sandwiched between the first surface of the substrate and the peeling surface may be cured by irradiating light to form an adhesive layer.

In addition, the method illustrated above does not limit the method of manufacturing the pressure-sensitive adhesive sheet disclosed herein. When manufacturing the adhesive sheet disclosed herein, an appropriate method capable of fixing the adhesive layer to the first surface of the substrate can be used individually or in combination of two or more types. Examples of such methods include a method of forming a pressure-sensitive adhesive layer by curing a liquid pressure-sensitive adhesive composition on the first side of a substrate as described above, or a method of subjecting the first side of the substrate to surface treatment to improve the anchoring properties of the pressure-sensitive adhesive layer. etc. can be mentioned. For example, when the anchoring property of the adhesive layer to the substrate can be sufficiently improved by a method such as providing an undercoat layer on the first side of the substrate, the cured adhesive layer can be bonded to the first side of the substrate. A pressure-sensitive adhesive sheet may be manufactured using the method. Additionally, the anchoring property of the adhesive layer to the substrate can be improved by selecting the material of the substrate or the composition of the adhesive. Additionally, by applying a temperature higher than room temperature to a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer on the first side of the substrate, the anchoring properties of the pressure-sensitive adhesive layer to the substrate can be improved. The temperature applied to improve anchoring properties may be, for example, about 35°C to 80°C, about 40°C to 70°C, or about 45°C to 60°C.

The adhesive sheet disclosed herein is in the form of an adhesive sheet (i.e., a double-sided adhesive adhesive sheet with a substrate) having a first adhesive layer provided on the first side of the substrate and a second adhesive layer provided on the second side of the substrate. In this case, the first adhesive layer and the second adhesive layer may have the same structure or different structures. When the first adhesive layer and the second adhesive layer have different compositions, the difference may be, for example, a difference in composition or structure (thickness, surface roughness, formation range, formation pattern, etc.). For example, the second adhesive layer may be an adhesive layer that does not contain polymer B. Additionally, the adhesive properties of the surface (second adhesive surface) of the second adhesive layer are not particularly limited. For example, the initial adhesive force, adhesive force after heating, and adhesive strength increase ratio of the second adhesive surface may each be the same as the characteristics of the first adhesive surface described above. Alternatively, the second adhesive surface may exhibit different characteristics from the first adhesive surface. For example, the adhesive force increase ratio of the second adhesive surface may be less than 2, may be less than 1.5, may be less than 1.2, or may be less than 1.

<Adhesive sheet with release liner>

The adhesive sheet disclosed herein may take the form of an adhesive product in which the surface (adhesive surface) of the adhesive layer is brought into contact with the release surface of the release liner. Therefore, by this specification, an adhesive sheet with a release liner (adhesive product) can be provided, which includes any of the adhesive sheets disclosed herein and a release liner having a release surface that contacts the adhesive surface of the adhesive sheet.

The thickness of the release liner is not particularly limited, but is usually about 5 μm to 200 μm. If the thickness of the release liner is within the above range, it is preferable because the bonding workability to the pressure-sensitive adhesive layer and the peeling workability from the pressure-sensitive adhesive layer are excellent. In some embodiments, the thickness of the release liner may be, for example, 10 μm or more, 20 μm or more, 30 μm or more, or 40 μm or more. In addition, the thickness of the release liner may be, for example, 100 μm or less or 80 μm or less from the viewpoint of facilitating peeling from the adhesive layer. The release liner may be subjected to known antistatic treatment, such as coating type, paste type, or vapor deposition type, as needed.

The release liner is not particularly limited and includes, for example, a release liner having a release layer on the surface of a liner base material such as a resin film or paper (possibly paper laminated with a resin such as polyethylene), or a fluorine-based polymer (polytetra). A release liner containing a resin film formed of a low-adhesion material such as fluoroethylene or polyolefin resin (polyethylene, polypropylene, etc.) can be used. Since the surface smoothness is excellent, a release liner having a release layer on the surface of a resin film as the liner base material or a release liner including a resin film formed of a low-adhesive material can be preferably employed. The resin film is not particularly limited as long as it is a film that can protect the adhesive layer, and examples include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, and vinyl chloride film. Examples include composite films, polyester films (PET films, PBT films, etc.), polyurethane films, and ethylene-vinyl acetate copolymer films. For forming the peeling layer, known peeling agents such as silicone-based peeling agents, long-chain alkyl-based peeling agents, olefin-based peeling agents, fluorine-based peeling agents, fatty acid amide-based peeling agents, molybdenum sulfide, and silica powder can be used. there is.

The thickness of the peeling layer is not particularly limited, but is usually about 0.01 μm to 1 μm, and is preferably about 0.1 μm to 1 μm. The method of forming the release layer is not particularly limited, and a known method can be appropriately adopted depending on the type of release treatment agent used, etc.

<Use>

The adhesive sheet provided by this specification, for example, after bonding to an adherend, has low adhesive strength for a while at room temperature, and can exhibit good rework properties during this period, thereby suppressing yield decline and adhesion. It can contribute to improving the quality of products including sheets. Additionally, the adhesive strength of the adhesive sheet can be greatly increased by aging (which may be heating, aging, a combination thereof, etc.). For example, by heating at a desired timing, the adhesive sheet can be firmly adhered to the adherend. As a result, the degree of freedom in handling the adhesive sheet increases, for example, in the manufacture of electronic devices such as portable electronic devices that include a step of bonding the adhesive sheet to an adherend, or in the manufacture of automobiles and home appliances, etc. Therefore, the adhesive sheet can be suitably used as a bonding material in electronic devices, automobiles, home appliances, etc., for example. In addition, for example, it can be preferably used for optical purposes such as adhesion of optical films used in image display devices such as liquid crystal displays, plasma displays, and organic EL displays. The pressure-sensitive adhesive sheet disclosed herein may be configured to use the above-described optical film as a substrate (support substrate).

Matters disclosed by this specification include the following.

(1) An adhesive sheet including an adhesive layer,

The adhesive layer includes polymer A and polymer B,

The polymer B has a side chain having an EG group at the terminal,

The monomer component forming the polymer B includes monomer m1 that introduces the side chain into the polymer B,

Here, the EG group is,

EG1 group: a hydrocarbon group having 12 to 22 carbon atoms, which may be halogenated, and

EG2 group: Halogenated hydrocarbon group with 11 or less carbon atoms

is selected from the group consisting of,

When bonded to a stainless steel plate, the adhesive force N1 after 30 minutes at 23°C is 10N/25mm or less, and

An adhesive sheet whose adhesive force N2 is twice or more than the adhesive force N1 after being joined to a stainless steel plate and heated at 80°C for 5 minutes and then heated at 23°C for 30 minutes.

(2) The adhesive sheet according to (1) above, wherein the polymer A is an acrylic polymer.

(3) The pressure-sensitive adhesive sheet according to (1) or (2) above, wherein the glass transition temperature (T _A ) of the polymer A is less than 0°C.

(4) The pressure-sensitive adhesive sheet according to any one of (1) to (3) above, wherein the weight average molecular weight of the polymer B is 1×10 ⁴ or more and 10×10 ⁴ or less.

(5) The pressure-sensitive adhesive sheet according to any one of (1) to (4) above, wherein the polymer B is an acrylic polymer.

(6) The pressure-sensitive adhesive sheet according to any one of (1) to (5) above, wherein the monomer m1 contains (meth)acrylate having the EG1 group at the ester terminal.

(7) The pressure-sensitive adhesive sheet according to any one of (1) to (6) above, wherein the monomer m1 contains (meth)acrylate having the EG2 group at the ester terminal.

(8) The pressure-sensitive adhesive sheet according to any one of (1) to (7) above, wherein the monomer component contains 2% by weight or more of the monomer m1.

(9) The pressure-sensitive adhesive sheet according to any one of (1) to (8) above, wherein the monomer component contains a (meth)acrylate having an alkyl group of 11 or less carbon atoms at the ester terminal.

(10) The pressure-sensitive adhesive sheet according to any one of (1) to (9) above, wherein the polymer B is a polymer that does not contain a functional group that causes a crosslinking reaction with the polymer A.

(11) The pressure-sensitive adhesive sheet according to any one of (1) to (10) above, wherein the pressure-sensitive adhesive layer contains 1 part by weight or more and 100 parts by weight or less of the polymer B based on 100 parts by weight of the polymer A.

(12) The pressure-sensitive adhesive sheet according to any one of (1) to (11) above, wherein the glass transition temperature (T _B ) of the polymer B is 0°C or higher and 100°C or lower.

(13) The pressure-sensitive adhesive sheet according to (12) above, wherein the glass transition temperature (T _B ) of the polymer B is 30°C or more higher than the glass transition temperature ( _TA ) of the polymer A.

(14) The pressure-sensitive adhesive sheet according to any one of (1) to (13) above, wherein the monomer component for preparing the polymer A contains a hydroxyl group-containing monomer.

(15) The pressure-sensitive adhesive sheet according to any one of (1) to (14) above, wherein the monomer component for preparing the polymer A contains N-vinyl cyclic amide and a hydroxyl group-containing monomer.

(16) The adhesive sheet according to any one of (1) to (15) above, wherein an isocyanate-based crosslinking agent is used in the adhesive layer.

(17) The adhesive sheet according to any one of (1) to (16) above, wherein the adhesive layer contains a multifunctional monomer.

(18) The adhesive sheet according to any one of (1) to (17) above, wherein the adhesive layer has a thickness of 3 μm or more and 100 μm or less.

(19) The adhesive sheet according to any one of (1) to (18) above, comprising a support substrate having a first side and a second side, and the adhesive layer being laminated on at least the first side of the support substrate. .

(20) The pressure-sensitive adhesive sheet according to (19) above, wherein the thickness of the support substrate is 30 μm or more.

(21) The adhesive sheet according to any one of (1) to (20) above, wherein the adhesive force N1 is less than 7 N/25 mm.

(22) The adhesive sheet according to any one of (1) to (21) above, wherein the adhesive force N2 is 10 N/25 mm or more.

[Example]

Hereinafter, several embodiments of the present invention will be described, but it is not intended to limit the present invention to those shown by these specific examples. In addition, “part” and “%” in the following description are based on weight unless otherwise specified.

<Preparation of polymer A>

(Polymer A1)

In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, and condenser, 60 parts of 2-ethylhexyl acrylate (2EHA), 15 parts of N-vinyl-2-pyrrolidone (NVP), and methyl methacrylate. Add 10 parts of (MMA), 15 parts of 2-hydroxyethyl acrylate (HEA), and 200 parts of ethyl acetate as a polymerization solvent, stir for 2 hours at 60°C under a nitrogen atmosphere, and then add 2,2'- as a thermal polymerization initiator. 0.2 parts of azobisisobutyronitrile (AIBN) was added, reaction was performed at 60°C for 6 hours, and a solution of polymer A1 was obtained. The Mw of this polymer A1 was 1.1 million. Tg calculated from the composition of the monomer component of polymer A1 is -38.3°C.

<Preparation of polymer B>

(polymer b1)

In a four-neck flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, condenser, and dropping funnel, 100 parts of ethyl acetate, 40 parts of MMA, 20 parts of n-butyl methacrylate (BMA), and 2-ethylhexyl methacrylate. 20 parts of (2EHMA), 20 parts of stearyl acrylate (STA), and 0.8 parts of α-thioglycerol were added. Then, after stirring at 70°C for 1 hour in a nitrogen atmosphere, 0.2 parts by weight of AIBN was added as a thermal polymerization initiator, and after reacting at 70°C for 2 hours, 0.1 parts by weight of AIBN was added as a thermal polymerization initiator, and then continued at 80°C for 5 hours. reacted over time. In this way, a solution of polymer b1 having a side chain having a stearyl group at the terminal (EG1 side chain derived from STA) was obtained. The Mw of this polymer b1 was 2.05×10 ⁴ .

(polymers b2 to b4)

The composition of the monomer component was changed as shown in Table 1, and the EG1 side chain was prepared in the same manner as in the preparation of polymer b1, except that the amount of α-thioglycerol used was adjusted so that ^Mw was in the range of 1.5 × 10 ⁴ to 2.5 × 10 4. Polymers b2 to b4 having were prepared. The Mw of each polymer was 1.99×10 ⁴ for polymer b2, 2.09×10 ⁴ for polymer b3, and 2.05×10 ⁴ for polymer b4. In addition, in the table, iSTA represents isostearyl acrylate, SMA represents stearyl methacrylate, and iSMA represents isostearyl methacrylate.

(polymers b5 to b6)

The composition of the monomer component was changed as shown in Table 1, and the EG2 side chain was prepared in the same manner as in the preparation of polymer b1, except that the amount of α-thioglycerol used was adjusted so that Mw ^was in the range of 1.5 × 10 ⁴ to 2.5 × 10 4. Polymers b5 to b6 having were prepared. The Mw of each polymer was 2.17×10 ⁴ for polymer b5 and 2.22×10 ⁴ for polymer b6. In addition, 4F in the table represents 2,2,3,3-tetrafluoropropylacrylate (manufactured by Osaka Yuki Chemical Co., Ltd., brand name "Viscott 4F").

(polymers b7 to b11)

Except that the composition of the monomer component was changed as shown in Table 2 and the amount of α-thioglycerol used was adjusted appropriately, preparation of polymer b1 was carried out similarly to polymers b7 to b10 having an EG1 side chain and polymers not having an EG side chain. b11 was prepared. The Mw of each polymer was 2.06×10 ⁴ for polymer b7, 1.98×10 ⁴ for polymer b8, 2.14×10 ⁴ for polymer b9, 1.97×10 ⁴ for polymer b10, and 0.5×10 ⁴ for polymer b11. Additionally, in Table 2, DCPMA represents dicyclopentanyl methacrylate.

(polymer b12)

In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, condenser, and dropping funnel, 100 parts of ethyl acetate, 40 parts of MMA, 20 parts of BMA, 20 parts of 2EHMA, and a polyorganosiloxane skeleton with a functional group equivalent of 2990 g/mol were added. 20 parts of the containing monomer (S1) and 0.8 parts of α-thioglycerol as a chain transfer agent were added. As the polyorganosiloxane skeleton-containing monomer (S1), 8.7 parts of polyorganosiloxane skeleton-containing methacrylate monomer (product name: 11.3 parts of a polyorganosiloxane skeleton-containing methacrylate monomer (product name: KF-2012, manufactured by Shin-Etsu Chemical Co., Ltd.) having a functional group equivalent weight of 4600 g/mol was used. Then, after stirring at 70°C for 1 hour under a nitrogen atmosphere, 0.2 part of AIBN was added as a thermal polymerization initiator, and after reacting at 70°C for 2 hours, 0.1 part of AIBN was added as a thermal polymerization initiator, and then continued at 80°C for 5 hours. reacted. In this way, a solution of polymer b12 was obtained. The Mw of this polymer b12 was 2.2×10 ⁴ .

The weight average molecular weight (Mw) of each polymer mentioned above was measured under the following conditions using a GPC device (HLC-8220GPC manufactured by Tosoh Corporation) and calculated by polystyrene conversion.

[GPC conditions]

ㆍSample concentration: 0.2wt% (tetrahydrofuran (THF) solution)

ㆍSample injection volume: 10μl

ㆍEluent: THF ㆍFlow rate: 0.6ml/min

ㆍMeasurement temperature: 40℃

ㆍColumn:

sample column; TSKguardcolumn SuperHZ-H (1 pc.) + TSKgel SuperHZM-H (2 pcs.)

Reference column; TSKgel SuperH-RC (1 unit)

ㆍDetector: Differential refractometer (RI)

In addition, the Tg calculated based on the composition of the monomer component used in preparing polymers b1 to b11 is as follows. Polymer b1: 43℃, Polymer b2: 31℃, Polymer b3: 45℃, Polymer b4: 43℃, Polymer b5: 36℃, Polymer b6: 35℃, Polymer b7: 46℃, Polymer b8: 44℃, Polymer b9 : 58℃, polymer b10: 24℃, polymer b11: 144℃.

In addition, in calculating the above Tg, the following values were used as the homopolymer Tg of each monomer. MMA: 105°C, BMA: 20°C, 2EHMA: -10°C, STA: 30°C, iSTA: -18°C, SMA: 38°C, iSMA: 30°C, 4F: -4°C, DCPMA: 175°C.

<Production of adhesive sheet>

(Example 1)

To the solution of polymer A1, 2.5 parts of polymer b1 and 2.5 parts of isocyanate-based crosslinking agent (trade name: Takenate D110N, trimethylolpropanexylylene diisocyanate, manufactured by Mitsui Chemicals) are added per 100 parts of polymer A1 contained in the solution. were added and mixed uniformly to prepare adhesive composition C1.

The adhesive composition C1 is applied directly to the first side of a 125 μm thick polyethylene terephthalate (PET) film (manufactured by Toray Industries, Ltd., brand name “Lumirror”) as a support substrate, and dried by heating at 110°C for 2 minutes, thereby forming the support substrate. A pressure-sensitive adhesive sheet (single-sided pressure-sensitive adhesive sheet with base material) was obtained in the form of a pressure-sensitive adhesive layer with a thickness of 25 μm laminated on the first side of . The release surface of the release liner R1 was bonded to the adhesive surface of this adhesive sheet to form an adhesive sheet with a release liner. As the release liner R1, a product name “Diafoil MRF” manufactured by Mitsubishi Chemical Corporation (a release liner in which one side of the polyester film is a release surface with a silicone-based release treatment agent, thickness 38 μm) was used.

(Examples 2 to 7)

Adhesive compositions C2 to C7 were prepared in the same manner as preparation of adhesive composition C1, except that the type and amount of polymer B used were changed as shown in Table 1. The adhesive sheets according to Examples 2 to 7 were produced in the same manner as the production of the adhesive sheets according to Example 1, except that the obtained adhesive compositions C2 to C7 were used, respectively.

(Examples 8 to 9)

Adhesive compositions C8 to C9 were prepared in the same manner as preparation of adhesive composition C1, except that the type and amount of polymer B used were changed as shown in Table 1. The adhesive sheets according to Examples 8 to 9 were produced in the same manner as the production of the adhesive sheets according to Example 1, except that the obtained adhesive compositions C8 to C9 were used, respectively.

(Examples 10 to 19)

Adhesive compositions C10 to C19 were prepared in the same manner as preparation of adhesive composition C1, except that the type and amount of polymer B used were changed as shown in Table 2. The adhesive sheets according to Examples 10 to 19 were produced in the same manner as the production of the adhesive sheets according to Example 1, except that the obtained adhesive compositions C10 to C19 were used, respectively.

<Measurement of adhesion to SUS>

The adhesive sheet for each example was cut to a width of 25 mm with a release liner as a test piece, and a SUS board (SUS304BA board) purified in toluene was used as an adherend, and the initial adhesive strength and adhesive strength after heating were measured in the following procedures.

(Measurement of initial adhesion (N1))

Under a standard environment of 23°C and 50% RH, the release liner covering the adhesive surface of each test piece was peeled off, and the exposed adhesive surface was pressed to the adherend by rotating a 2 kg roller once. The test piece pressed to the adherend in this way is left in the above standard environment for 30 minutes, and then peeled using a universal tensile compression tester (device name “tensile compression tester, TCM-1kNB” manufactured by Minebea) in accordance with JIS Z0237. Under the conditions of an angle of 180 degrees and a pulling speed of 300 mm/min, the 180° peel adhesion (resistance to the pulling) was measured. The measurement was performed three times, and the average value was taken as the initial adhesive force (N1).

(Measurement of adhesion (N2) after heating)

In the same manner as the measurement of initial adhesive force, the test piece pressed to the adherend was heated at 80°C for 5 minutes and then left to stand for 30 minutes in the above-mentioned standard environment, and then the 180° peel adhesive force was measured in the same manner. The measurement was performed three times, and the average value was taken as the adhesive force after heating (N2).

(Calculation of adhesion increase ratio (N2/N1))

Based on the initial adhesive force (N1) and the adhesive force after heating (N2) obtained by the above measurement, the adhesive force increase ratio (N2/N1) was calculated.

The obtained results are shown in Tables 1 and 2. These tables also show the composition of the monomer components used in the preparation of polymers b1 to b12.

As shown in these tables, the adhesive sheet of Example 18, which does not have either the EG1 side chain or the EG2 side chain, exhibited high adhesive strength from the initial stage of application, but was poor in reworkability. In contrast, the adhesive sheets of Examples 1 to 7, Examples 8 to 9, and Examples 10 to 17 having an EG side chain initially exhibit low adhesiveness that can be reworked, similar to the adhesive sheet of Example 19, and the adhesive strength increases by heating. It showed a unique property of rising significantly.

Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the patent claims. The technology described in the patent claims includes various modifications and changes to the specific examples illustrated above.

1, 2, 3: Adhesive sheet
10: Supporting substrate
10A: side 1
10B: Side 2
21: Adhesive layer (first adhesive layer)
21A: Adhesive side (first adhesive side)
21B: Adhesive side (second adhesive side)
22: Adhesive layer (second adhesive layer)
22A: Adhesive side (second adhesive side)
31, 32: release liner
100, 200, 300: Adhesive sheet with release liner (adhesive product)

Claims (11)

It is an adhesive sheet containing an adhesive layer,
The adhesive layer includes polymer A and polymer B,
The polymer A is an acrylic polymer,
The glass transition temperature (T _A ) of the polymer A is less than 0°C,
The monomer component forming the polymer A includes a hydroxyl group-containing monomer,
The polymer B is an acrylic polymer,
The polymer B has a side chain having an EG group at the terminal,
The monomer component forming the polymer B includes monomer m1 that introduces the side chain into the polymer B,
Here, the EG group is,
EG1 group: a hydrocarbon group having 12 to 22 carbon atoms, which may be halogenated, and
EG2 group: Halogenated hydrocarbon group with 11 or less carbon atoms
is selected from the group consisting of,
The monomer component forming the polymer B further includes (meth)acrylate having an alkyl group of 11 or less carbon atoms at the ester terminal,
The glass transition temperature (T _B ) of the polymer B is 0°C or more and 100°C or less,
When bonded to a stainless steel plate, the adhesive force N1 after 30 minutes at 23°C is 10N/25mm or less, and
An adhesive sheet whose adhesive force N2 is twice or more than the adhesive force N1 after being joined to a stainless steel plate and heated at 80°C for 5 minutes and then heated at 23°C for 30 minutes. delete delete According to paragraph 1,
The weight average molecular weight of the polymer B is 1×10 ⁴ or more and 10×10 ⁴ or less. delete According to paragraph 1,
An adhesive sheet in which the monomer m1 contains (meth)acrylate having the EG1 group at the ester terminal. According to paragraph 1,
An adhesive sheet in which the monomer m1 contains (meth)acrylate having the EG2 group at the ester terminal. According to paragraph 1,
An adhesive sheet in which the monomer component contains 2% by weight or more of the monomer m1. delete According to paragraph 1,
The adhesive layer is an adhesive sheet containing 1 part by weight or more and 100 parts by weight or less of the polymer B based on 100 parts by weight of the polymer A. According to paragraph 1,
A pressure-sensitive adhesive sheet comprising a support base material having a first side and a second side, and the pressure-sensitive adhesive layer being laminated on at least the first surface of the support base material.