JP2021138966A - Adhesive composition, adhesive sheet, and optical member - Google Patents

Abstract

To provide an adhesive composition that is less likely to cause sliding (displacing), floating, and peeling with respect to an optical component such as a polarizing plate, has excellent curl adjusting performance, and can keep the peeling voltage low; an adhesive sheet formed from the adhesive composition; and an optical member having the adhesive sheet bonded thereto.SOLUTION: This adhesive composition contains an adhesive polymer, a fluorine-containing oligomer having a weight average molecular weight of 3500 or more, and an ionic compound.SELECTED DRAWING: None

Description

The present invention relates to pressure-sensitive adhesive compositions, pressure-sensitive adhesive sheets, and optical members. In particular, the pressure-sensitive adhesive sheet obtained from the pressure-sensitive adhesive composition is used for being attached to plastic products or the like that easily generate static electricity (for example, liquid crystal display panel, plasma display panel (PDP), organic electroluminescence (EL) display, etc.). It is particularly suitable for the purpose of protecting the surface of optical members (for example, polarizing plates, wavelength plates, retardation plates, optical compensation films, reflective sheets, brightness improving films used in liquid crystal displays and the like). It is useful as a surface protective film to be used.

A surface protective film (also referred to as a surface protective sheet) generally has a structure in which an adhesive layer is provided on a film-like base film (support). Such a protective film is attached to an adherend (protected body) via the pressure-sensitive adhesive layer, and is used for the purpose of protecting the adherend from scratches and stains during processing and transportation. For example, a panel of a liquid crystal display is formed by bonding optical members such as a polarizing plate and a wave plate to a liquid crystal cell via an adhesive layer. In the manufacture of such a liquid crystal display panel, the polarizing plate to be bonded to the liquid crystal cell is once manufactured in a roll form, then unwound from the roll and cut into a desired size according to the shape of the liquid crystal cell for use. .. Here, in order to prevent the polarizing plate from being scratched by rubbing against the transport roll or the like in the intermediate process, measures are taken to attach a surface protective film to one side or both sides (typically one side) of the polarizing plate. This surface protective film is peeled off and removed when it is no longer needed.

Since the surface protective film and the optical member are usually made of a plastic material, they have high electrical insulation and generate static electricity due to friction or peeling. Therefore, static electricity is likely to be generated even when the surface protective film is peeled off from an optical member such as a polarizing plate, and if a voltage is applied to the liquid crystal with the static electricity remaining, the orientation of the liquid crystal molecules may be lost or the orientation of the liquid crystal molecules may be lost. In addition, there is a concern that the panel may be damaged. In addition, the presence of static electricity can be a factor of sucking dust and reducing workability. For this reason, antistatic treatment is applied to the surface protective film. For example, as the surface layer (top coat layer, back layer) of the surface protective film, an antistatic layer is formed or an antistatic coating is applied. (See Patent Documents 1 and 2).

Further, in order to impart antistatic properties to the pressure-sensitive adhesive layer itself constituting the surface protective film, an ionic compound such as an alkali metal salt or an ionic liquid that functions as an antistatic agent is contained in the pressure-sensitive adhesive. (See Patent Document 3).

Further, when the surface protective film is attached to an adherend (polarizing plate, etc.), unnecessary curl or unintended curl (curl) is applied to the adherend (polarizing plate, etc.) to which the surface protective film is attached. Refers to a phenomenon of warping, for example, a phenomenon in which a flat plate-shaped object is totally warped toward one of the surfaces, a phenomenon in which a flat plate-shaped object is totally wavy and warped, etc.) Adjustability has been required. If unnecessary curl or unintended curl occurs, the handleability is poor, and for example, when an adherend such as a polarizing plate is attached to the liquid crystal cell, problems such as air bubbles may be caught.

When curling occurs in a flat-plate-shaped adherend, a force associated with curling acts in the shearing direction on the pressure-sensitive adhesive layer of the surface protective film attached to the adherend, and this force acts on the adherend and the pressure-sensitive adhesive. Since slippage (displacement) or the like gradually occurs between the layers, it is required to improve the shearing force at the time of low-speed peeling.

In addition, it has an appropriate adhesive strength so that the surface protective film does not float or peel off during processing and transportation of the adherend (protected body), and is lightly peelable (removable) at low speed peeling. ) Is required.

Therefore, in order to realize light peeling, various methods are applied to the pressure-sensitive adhesive composition used for the surface protective film. For example, examples have been reported in which the polymer used in the pressure-sensitive adhesive composition contains a component having a high glass transition temperature (Tg), a reactive surfactant, or the like, and a case in which the pressure-sensitive adhesive composition is highly crosslinked (for example,). See Patent Document 4).

However, in the above method, even when light peeling can be realized, the additive is added at the interface between the pressure-sensitive adhesive layer and the adherend by containing an additive such as an ionic compound or a surfactant. Bleed out, causing contamination, and there is also a concern that slippage (misalignment) is likely to occur.

Japanese Unexamined Patent Publication No. 2004-223923 Japanese Unexamined Patent Publication No. 2008-255332 Japanese Unexamined Patent Publication No. 9-165460 JP-A-2002-221906

Therefore, as a result of diligent research in view of the above circumstances, the present invention is less likely to cause slippage, floating or peeling with respect to an optical member such as a polarizing plate, is excellent in curl adjustability, and has a low peeling band voltage. It is an object of the present invention to provide a pressure-sensitive adhesive composition for obtaining a pressure-sensitive adhesive layer and a pressure-sensitive adhesive sheet that can be suppressed, a pressure-sensitive adhesive sheet formed by the pressure-sensitive adhesive composition, and an optical member to which the pressure-sensitive adhesive sheet is attached.

That is, the pressure-sensitive adhesive composition of the present invention is characterized by containing a pressure-sensitive polymer, a fluorine-based oligomer having a weight average molecular weight of 3500 or more, and an ionic compound.

The pressure-sensitive adhesive composition of the present invention preferably contains an oxyalkylene group-containing compound.

In the pressure-sensitive adhesive composition of the present invention, the pressure-sensitive adhesive polymer is preferably at least one selected from the group consisting of (meth) acrylic polymers, urethane-based polymers, and silicone-based polymers.

The pressure-sensitive adhesive sheet of the present invention has a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition on at least one side of the base film, and the fluorine-based oligomer is contained inside and / or on the surface of the pressure-sensitive adhesive layer. It is preferable to be present.

In the pressure-sensitive adhesive sheet of the present invention, it is preferable that a separator is attached to the surface of the pressure-sensitive adhesive layer opposite to the surface in contact with the base film.

In the pressure-sensitive adhesive sheet of the present invention, it is preferable that the fluorine-based oligomer is present on the surface of the separator that comes into contact with the pressure-sensitive adhesive layer.

The optical member of the present invention is preferably attached with the pressure-sensitive adhesive sheet or a pressure-sensitive adhesive sheet obtained by peeling the separator from the pressure-sensitive adhesive sheet.

In the present invention, by using a pressure-sensitive adhesive composition containing a specific fluorine-based oligomer and an ionic compound, a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed by the pressure-sensitive adhesive composition can be made into an optical member such as a polarizing plate. Since it is possible to suppress the occurrence of slippage (displacement), floating and peeling after bonding to, it is excellent in curl adjustment property, and further, it is possible to suppress the peeling band voltage to be low, which is useful.

It is a schematic cross-sectional view which shows one structural example of the pressure-sensitive adhesive sheet (surface protection film) which concerns on this invention. It is explanatory drawing which shows the measuring method of the peeling band voltage.

Hereinafter, embodiments of the present invention will be described in detail.

<Overall structure of adhesive sheet (surface protection film)>
The pressure-sensitive adhesive sheet disclosed herein is generally in the form of a pressure-sensitive adhesive tape, a pressure-sensitive adhesive label, a pressure-sensitive adhesive film, or the like, and is particularly used as a component of a liquid crystal display panel such as an optical component (for example, a polarizing plate or a wave plate). It is suitable as a surface protective film that protects the surface of the optical component during processing or transportation. The pressure-sensitive adhesive layer in the surface protective film is typically formed continuously, but is not limited to such a form, and is formed in a regular or random pattern such as a dot shape or a striped shape. It may be an adhesive layer. Further, the surface protective film disclosed herein may be in the form of a roll or in the form of a single leaf.

<Base film>
The pressure-sensitive adhesive sheet (surface protective film) of the present invention is characterized by having a base film. In the technique disclosed herein, the resin material constituting the base film can be used without particular limitation, and for example, transparency, mechanical strength, thermal stability, moisture shielding property, isotropic property, and the like are possible. It is preferable to use one having excellent properties such as flexibility and dimensional stability. In particular, since the base film has flexibility, the pressure-sensitive adhesive composition can be applied by a roll coater or the like, and can be wound into a roll shape, which is useful.

As the base film (base material, support), for example, polyester-based polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate; cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose; polycarbonate. Based polymer; Acrylic polymer such as polymethylmethacrylate; A plastic film composed of a resin material containing the main resin component (main component of the resin component, typically a component accounting for 50% by mass or more). It can be preferably used as the base film. Other examples of the resin material include styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymers; olefin-based polymers such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene copolymers; Examples thereof include those using a vinyl chloride polymer; an amide polymer such as nylon 6, nylon 6, 6, and aromatic polyamide; and the like as a resin material. Still other examples of the resin material include imide-based polymers, sulfone-based polymers, polyether sulfone-based polymers, polyether ether ketone-based polymers, polyphenylene sulfide-based polymers, vinyl alcohol-based polymers, vinylidene chloride-based polymers, and vinyl butyral-based polymers. , Arilate-based polymer, polyoxymethylene-based polymer, epoxy-based polymer and the like. It may be a base film composed of a blend of two or more of the above-mentioned polymers.

As the base film, a plastic film made of a transparent thermoplastic resin material can be preferably adopted. Among the plastic films, it is more preferable to use a polyester film. Here, the polyester film mainly contains a polyester polymer material (polyester resin) having a main skeleton based on an ester bond such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate. Say something. Such a polyester film has preferable properties as a base film for a surface protective film, such as excellent optical properties and dimensional stability, but has a property of being easily charged as it is.

If necessary, the resin material constituting the base film may contain various additives such as an antioxidant, an ultraviolet absorber, a plasticizer, and a colorant (pigment, dye, etc.). For example, known or conventional surface treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and undercoating may be applied. Such a surface treatment may be, for example, a treatment for enhancing the adhesion between the base film and the pressure-sensitive adhesive layer (the anchoring property of the pressure-sensitive adhesive layer).

As the pressure-sensitive adhesive sheet (surface protective film) of the present invention, it is also possible to use a plastic film which has been subjected to antistatic treatment as the base film. It is preferable to use the base film because the charge of the pressure-sensitive adhesive sheet itself at the time of peeling can be suppressed. Further, the base film is a plastic film, and by subjecting the plastic film to an antistatic treatment, it is possible to reduce the charge on the pressure-sensitive adhesive sheet itself and obtain an excellent antistatic ability on the adherend. The method for imparting the antistatic function is not particularly limited, and a conventionally known method can be used. For example, an antistatic resin, a conductive polymer, or a conductive substance composed of an antistatic agent and a resin component can be used. Examples thereof include a method of applying the contained conductive resin, a method of depositing or plating a conductive substance, and a method of kneading an antistatic agent or the like.

The thickness of the base film is usually about 5 to 200 μm, preferably about 10 to 100 μm. When the thickness of the base film is within the above range, it is preferable because it is excellent in the workability of attaching to the adherend and the workability of peeling from the adherend.

The pressure-sensitive adhesive sheet disclosed herein may be implemented in an embodiment including a base film and a pressure-sensitive adhesive layer, as well as another layer. Examples of the other layer include an antistatic layer and an undercoat layer (anchor layer) that enhances the anchoring property of the pressure-sensitive adhesive layer.

<Adhesive composition>
The pressure-sensitive adhesive composition of the present invention can be used without particular limitation as long as it contains a pressure-sensitive adhesive polymer having adhesiveness, and a pressure-sensitive adhesive layer can be formed from the pressure-sensitive adhesive composition. As the pressure-sensitive adhesive composition, for example, an acrylic pressure-sensitive adhesive, a urethane-based pressure-sensitive adhesive, a synthetic rubber-based pressure-sensitive adhesive, a natural rubber-based pressure-sensitive adhesive, a silicone-based pressure-sensitive adhesive, or the like can be used, and more preferably. The adhesive polymer is at least one selected from the group consisting of a (meth) acrylic polymer, a urethane polymer, and a silicone polymer, and is an acrylic pressure-sensitive adhesive and urethane containing the (meth) acrylic polymer. It is more preferable to use (contain) at least one selected from the group consisting of a urethane-based pressure-sensitive adhesive containing a based polymer and a silicone-based pressure-sensitive adhesive containing a silicone-based polymer, and particularly preferably the adhesiveness. It is to use an acrylic pressure-sensitive adhesive that uses a (meth) acrylic polymer that is a polymer.

When the pressure-sensitive adhesive layer uses an acrylic pressure-sensitive adhesive, the (meth) acrylic-based polymer, which is a pressure-sensitive polymer constituting the acrylic pressure-sensitive adhesive, is an alkyl having 1 to 14 carbon atoms as a raw material monomer constituting the pressure-sensitive adhesive polymer. A (meth) acrylic monomer having a group can be used as the main monomer. As the (meth) acrylic monomer, one kind or two or more kinds can be used. By using the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, it becomes easy to control the peeling force (adhesive force) to the adherend (protected body) to be low, and light peeling becomes possible. An adhesive sheet (surface protective film) having excellent properties and removability can be obtained. The (meth) acrylic polymer in the present invention refers to an acrylic polymer and / or a methacrylic polymer, and the (meth) acrylate refers to an acrylate and / or methacrylate.

Specific examples of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and s-butyl (meth). ) Acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl ( Examples include meta) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, and n-tetradecyl (meth) acrylate. Be done.

Among them, when the pressure-sensitive adhesive sheet of the present invention is used as a surface protective film, n-butyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, Isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, Suitable examples include (meth) acrylic monomers having an alkyl group having 4 to 14 carbon atoms, such as n-tetradecyl (meth) acrylate. In particular, by using a (meth) acrylic monomer having an alkyl group having 4 to 14 carbon atoms, it becomes easy to control the peeling force (adhesive force) to the adherend to be low, and the material has excellent removability. It becomes.

In particular, it is preferable to contain 50% by mass or more of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms with respect to 100% by mass of the total amount of the monomer components constituting the (meth) acrylic polymer. , More preferably 80% by mass or more, further preferably 85 to 99.9% by mass, and most preferably 90 to 99% by mass. If it is less than 50% by mass, the appropriate wettability of the pressure-sensitive adhesive composition and the cohesive force of the pressure-sensitive adhesive layer will be inferior, which is not preferable.

Further, in the pressure-sensitive adhesive composition of the present invention, it is preferable that the (meth) acrylic polymer contains a hydroxyl group-containing (meth) acrylic monomer as a raw material monomer. As the hydroxyl group-containing (meth) acrylic monomer, one kind or two or more kinds can be used. By using the hydroxyl group-containing (meth) acrylic monomer, it becomes easier to control cross-linking of the pressure-sensitive adhesive composition, and by extension, a balance between improvement of wettability due to flow and reduction of peeling force (adhesive force) in peeling is achieved. It becomes easier to control.

Examples of the hydroxyl group-containing (meth) acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate. , 8-Hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, and the like. .. In particular, it is preferable to use a hydroxyl group-containing (meth) acrylic monomer having 4 or more carbon atoms in the alkyl group, which facilitates light peeling during high-speed peeling.

The hydroxyl group-containing (meth) acrylic monomer is preferably contained in an amount of 25% by mass or less, more preferably 20% by mass or less, based on 100% by mass of the total amount of the monomer components constituting the (meth) acrylic polymer. More preferably, it is 0.1 to 15% by mass, and most preferably 1 to 10% by mass. When it is within the above range, it is easy to control the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force of the obtained pressure-sensitive adhesive layer, which is preferable.

In addition, as other polymerizable monomer components, the Tg is set to 0 ° C. or lower (usually -100 ° C. or higher) so that the adhesive performance can be easily balanced, and the glass transition temperature and peeling of the (meth) acrylic polymer are set. A polymerizable monomer for adjusting the property can be used as long as the effect of the present invention is not impaired.

Examples of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms used in the (meth) acrylic polymer and the polymerizable monomer other than the hydroxyl group-containing (meth) acrylic monomer include A carboxyl group-containing (meth) acrylic monomer can be used. By using the carboxyl group-containing (meth) acrylic monomer, it is possible to suppress an increase in the adhesive strength of the pressure-sensitive adhesive layer (adhesive sheet) over time, and it is possible to suppress the increase in the adhesive strength over time, and the removability, the adhesive strength increase prevention property, and the workability. Excellent for. Further, it is preferable because it has excellent shearing force as well as cohesive force of the pressure-sensitive adhesive layer.

Examples of the carboxyl group-containing (meth) acrylic monomer include (meth) acrylic acid, carboxylethyl (meth) acrylate, and carboxylpentyl (meth) acrylate.

The amount of the carboxyl group-containing (meth) acrylic monomer is preferably 0 to 5% by mass, preferably 0 to 3% by mass, based on 100% by mass of the total amount of the monomer components constituting the (meth) acrylic polymer. More preferably, 0 to 2% by mass is further preferable, and 0 to 1% by mass is most preferable. When it is within the above range, it is easy to control the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force of the obtained pressure-sensitive adhesive layer, which is preferable.

When the hydroxyl group-containing (meth) acrylic monomer and the carboxyl group-containing (meth) acrylic monomer are used in combination, the total amount of the monomer components constituting the (meth) acrylic polymer is 100% by mass. , The carboxyl group-containing (meth) acrylic monomer is preferably contained in an amount of 0.005 to 0.1% by mass. By adjusting within the above range, a pressure-sensitive adhesive layer (adhesive sheet) having excellent removability and prevention of increase in adhesive strength can be further obtained, which is effective.

Further, the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms used in the (meth) acrylic polymer, the hydroxyl group-containing (meth) acrylic monomer, and the carboxyl group-containing (meth) acrylic monomer. As the polymerizable monomer other than the monomer, it can be used without particular limitation as long as it does not impair the characteristics of the present invention. For example, a cohesiveness / heat resistance improving component such as a cyano group-containing monomer, a vinyl ester monomer, and an aromatic vinyl monomer, an amide group-containing monomer, an imide group-containing monomer, an amino group-containing monomer, an epoxy group-containing monomer, and N-acryloylmorpholin. , A component having a functional group that acts as an improvement in peeling power (adhesive power) or a cross-linking base point, such as a vinyl ether monomer, can be appropriately used. Among them, it is preferable to use a cyano group-containing monomer, an amide group-containing monomer, an imide group-containing monomer, an amino group-containing monomer, and a nitrogen-containing monomer such as N-acryloylmorpholine. By using the nitrogen-containing monomer, it is possible to secure an appropriate peeling force (adhesive force) that does not cause floating or peeling, and it is possible to obtain an adhesive sheet (surface protective film) having excellent shearing force, which is useful. .. As these polymerizable monomers, one kind or two or more kinds can be used.

Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, N, N-dimethylmethacrylicamide, N, N-diethylacrylamide, N, N-diethyl. Examples thereof include methacrylamide, N, N'-methylenebisacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminopropyl methacrylamide, diacetone acrylamide and the like.

Examples of the imide group-containing monomer include cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and itaconimide.

Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and N, N-dimethylaminopropyl (meth) acrylate.

Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, vinyl laurate and the like.

Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene, and other substituted styrenes.

Examples of the epoxy group-containing monomer include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, and allyl glycidyl ether.

Examples of the vinyl ether monomer include methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether and the like.

In the present invention, other polymerizable monomers other than the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, the hydroxyl group-containing (meth) acrylic monomer, and the carboxyl group-containing (meth) acrylic monomer are described above. It is preferably 0 to 50% by mass, more preferably 0 to 20% by mass, based on 100% by mass of the total amount of the monomer components constituting the (meth) acrylic polymer. The other polymerizable monomers can be appropriately adjusted to obtain the desired properties.

The (meth) acrylic polymer may further contain an alkylene oxide group-containing reactive monomer as a monomer component.

The average number of moles of oxyalkylene units added to the alkylene oxide group-containing reactive monomer is preferably 1 to 40 from the viewpoint of compatibility with the oxyalkylene group-containing compound, and is preferably 3 to 40. Is more preferable, 4 to 35 is further preferable, and 5 to 30 is particularly preferable. When the average number of added moles is 1 or more, the effect of reducing contamination of the adherend (protected body) tends to be efficiently obtained. Further, when the average number of moles added is larger than 40, the interaction with the oxyalkylene group-containing compound is large, and the viscosity of the pressure-sensitive adhesive composition tends to increase, which tends to make coating difficult, which is not preferable. The terminal of the oxyalkylene chain may remain as a hydroxyl group or may be substituted with another functional group or the like.

The alkylene oxide group-containing reactive monomer may be used alone or in combination of two or more, but the total content is the total amount of the monomer components of the (meth) acrylic polymer. Of the above, it is preferably 0 to 20% by mass, and more preferably 0 to 10% by mass. If the content of the alkylene oxide group-containing reactive monomer exceeds 20% by mass, the contamination of the adherend deteriorates, which is not preferable.

Examples of the oxyalkylene unit of the alkylene oxide group-containing reactive monomer include those having an alkylene group having 1 to 6 carbon atoms, and examples thereof include an oxymethylene group, an oxyethylene group, an oxypropylene group and an oxybutylene group. Be done. The hydrocarbon group of the oxyalkylene chain may be linear or branched.

Further, it is more preferable that the alkylene oxide group-containing reactive monomer is a reactive monomer having an ethylene oxide group. By using a reactive monomer-containing (meth) acrylic polymer having an ethylene oxide group as a base polymer, the compatibility between the base polymer and a fluorine-based oligomer, an ionic compound, or an oxyalkylene group-containing compound is improved, and an adherend is formed. Bleeding to is preferably suppressed, and a low-staining pressure-sensitive adhesive composition is obtained.

Examples of the alkylene oxide group-containing reactive monomer include a (meth) acrylate alkylene oxide adduct and a reactive surfactant having a reactive substituent such as an acryloyl group, a methacryloyl group, or an allyl group in the molecule. can give.

Specific examples of the (meth) acrylate alkylene oxide adduct include polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, polyethylene glycol-polypropylene glycol (meth) acrylate, and polyethylene glycol-polybutylene glycol (meth). ) Acrylic, Polyethylene Glycol-Polybutylene Glycol (Meta) acrylate, methoxypolyethylene Glycol (Meta) acrylate, ethoxypolyethylene Glycol (Meta) acrylate, Butoxypolyethylene Glycol (Meta) acrylate, Octoxypolyethylene glycol (Meta) acrylate, Lauroxypolyethylene Glycol (meth) acrylate, stearoxypolyethylene glycol (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, methoxypolyethylene glycol (meth) acrylate, octoxypolyethylene glycol-polypropylene glycol (meth) acrylate and the like can be mentioned.

Specific examples of the reactive surfactant include, for example, an anionic reactive surfactant having a (meth) acryloyl group or an allyl group, a nonionic reactive surfactant, a cationic reactive surfactant, and the like. Can be given.

The (meth) acrylic polymer preferably has a weight average molecular weight (Mw) of 100,000 to 5 million, more preferably 200,000 to 4 million, still more preferably 300,000 to 3 million, and most preferably 300,000 to 950,000. Is. When the weight average molecular weight is less than 100,000, the cohesive force of the pressure-sensitive adhesive layer is reduced, which tends to cause adhesive residue. On the other hand, when the weight average molecular weight exceeds 5 million, the fluidity of the polymer decreases, the wettability to the adherend (for example, the polarizing plate) becomes insufficient, and the adherend and the adhesive sheet (surface protective film) It tends to cause blisters that occur between the adhesive layer. The weight average molecular weight is obtained by measuring by GPC (gel permeation chromatography).

The glass transition temperature (Tg) of the (meth) acrylic polymer is preferably 0 ° C. or lower, more preferably −10 ° C. or lower (usually −100 ° C. or higher). When the glass transition temperature is higher than 0 ° C., the polymer does not easily flow, for example, the polarizing plate, which is an optical member, is not sufficiently wetted, and between the polarizing plate and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet (surface protective film). It tends to cause blisters that occur. In particular, when the glass transition temperature is set to −61 ° C. or lower, it becomes easy to obtain an adhesive layer having excellent wettability to a polarizing plate and light peelability. The glass transition temperature of the (meth) acrylic polymer can be adjusted within the above range by appropriately changing the monomer component and composition ratio used.

The polymerization method of the (meth) acrylic polymer is not particularly limited, and can be polymerized by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, etc., but particularly from the viewpoint of workability and subject matter. Solution polymerization is a more preferable embodiment from the viewpoint of characteristics such as low contamination of the body (protected body). Further, the obtained polymer may be any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer and the like.

When a urethane-based pressure-sensitive adhesive is used for the pressure-sensitive adhesive layer, any suitable urethane-based pressure-sensitive adhesive may be adopted. Examples of such urethane-based pressure-sensitive adhesives include those made of urethane-based polymers, which are adhesive polymers obtained by reacting a polyol with a polyisocyanate compound. Examples of the polyol include a polyether polyol, a polyester polyol, a polycarbonate polyol, a polycaprolactone polyol, and the like. Examples of the polyisocyanate compound include diphenylmethane diisocyanate, tolylene diisocyanate, and hexamethylene diisocyanate.

When a silicone-based pressure-sensitive adhesive is used for the pressure-sensitive adhesive layer, any suitable silicone-based pressure-sensitive adhesive may be adopted. As such a silicone-based pressure-sensitive adhesive, preferably, one obtained by blending or aggregating a silicone-based polymer which is an adhesive polymer can be adopted.

Examples of the silicone-based pressure-sensitive adhesive include addition-reaction-curable silicone-based pressure-sensitive adhesives and peroxide-curable silicone-based pressure-sensitive adhesives. Among these silicone-based pressure-sensitive adhesives, addition reaction-curable silicone-based pressure-sensitive adhesives are preferable because peroxides (benzoyl peroxide and the like) are not used and decomposition products are not generated.

Examples of the curing reaction of the addition reaction curing type silicone-based pressure-sensitive adhesive include, for example, a method of curing a polyalkyl hydrogen siloxane composition with a platinum catalyst in the case of obtaining a polyalkyl silicone-based pressure-sensitive adhesive.

<Fluorine-based oligomer>
The pressure-sensitive adhesive composition of the present invention is characterized by containing a pressure-sensitive polymer, a fluorine-based oligomer having a weight average molecular weight of 3500 or more, and an ionic compound. When the pressure-sensitive adhesive layer (adhesive sheet) obtained by containing a fluorine-based oligomer having a weight average molecular weight of 3500 or more is attached to an optical member such as a polarizing plate, the pressure-sensitive adhesive composition contains fluorine in the fluorine-based oligomer. It exerts a light peeling effect due to the low surface free energy of the part, and the fluorine-based oligomer functions as an adhesive resin, improves the adhesiveness, and can suppress slipping (displacement), floating and peeling of the surface protective film. That is, it is possible to achieve both light peelability (removability) and adhesiveness, which is a preferable embodiment. Further, the pressure-sensitive adhesive sheet of the present invention has a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to any one of claims 1 to 3 on at least one side of the base film, and the inside of the pressure-sensitive adhesive layer. And / or preferably, the fluorine-based oligomer is present on the surface. The "inside" of the pressure-sensitive adhesive layer refers to, for example, a case where the pressure-sensitive adhesive layer is formed by using the pressure-sensitive adhesive composition containing the fluorine-based oligomer and is contained in the pressure-sensitive adhesive layer. .. The "surface" of the pressure-sensitive adhesive layer is, for example, the case where the fluorine-based oligomer contained in the pressure-sensitive adhesive layer containing the fluorine-based oligomer is present (exposed) on the surface of the pressure-sensitive adhesive layer, or the above. When the fluorine-based oligomer is applied (laminated) in advance on the surface of the separator to be attached to protect the surface of the pressure-sensitive adhesive layer, and the separator is attached to the pressure-sensitive adhesive layer, the fluorine is applied from the surface of the separator. Refers to the case where the system oligomer is transferred (transferred) to the surface of the pressure-sensitive adhesive layer.

The weight average molecular weight (Mw) of the fluorine-based oligomer is 3500 or more, preferably 5000 or more, more preferably 10000 or more, and further preferably 20000 or more. When the weight average molecular weight of the fluorine-based oligomer is 3500 or more, the function as a tackifier resin is more exhibited, the adhesiveness is improved, and slippage (displacement), floating and peeling of the surface protective film can be suppressed. Further, when the weight average molecular weight is 20000 or more, foaming at the time of blending the pressure-sensitive adhesive (composition) can be suppressed, and the appearance after coating with the pressure-sensitive adhesive is excellent, which is preferable. The upper limit of the weight average molecular weight (Mw) of the fluorine-based oligomer is preferably 200,000 or less, more preferably 100,000 or less. When the content is 200,000 or less, the fluorine-based oligomer is likely to segregate on the surface, and the light peeling effect is more likely to be exhibited, which is preferable.

As a specific example of the fluorine-based oligomer, for example, the trade names of commercially available products are Megafuck F-251, F-253, F-281, F-410, F-430, F-444, F-477, F. -510, F-511, F-551, F-552, F-553, F-554, F-555, F-556, F-557, F-558, F-559, F-560, F-561 , F-562, F-563, F-565, F-568, F-569, F-570, F-571, F-572 (all manufactured by DIC Corporation), Surflon S-611, S-651, S -386 (all manufactured by AGC Seimi Chemical Co., Ltd.), Fluorent 610FM, 710FL, 710FM, 710FS, 730FL, 730LM (all manufactured by Neos Co., Ltd.) and the like. These compounds may be used alone or in combination of two or more.

The content of the fluorine-based oligomer is based on 100 parts by mass of the adhesive polymer (base polymer, for example, (meth) acrylic polymer, urethane-based polymer, silicone-based polymer, etc.) constituting the pressure-sensitive adhesive composition. , 0.01 to 10 parts by mass, more preferably 0.02 to 7.5 parts by mass, still more preferably 0.03 to 5.5 parts by mass, and most preferably 0.04 to 4.8 parts by mass. It is a department. When it is within the above range, after the pressure-sensitive adhesive sheet of the present invention is attached to an optical member or the like, slippage (displacement), floating or peeling can be suppressed, and further, it is excellent in light peelability, which is preferable. Further, in order to satisfy the stain resistance, the content of the fluorine-based oligomer is preferably 0.01 to 5.5 parts by mass with respect to 100 parts by mass of the adhesive polymer.

<Ionic compound>
The pressure-sensitive adhesive composition contains an ionic compound, and it is preferable to use at least one of an alkali metal salt, an ionic liquid, and an ionic group-containing silicone as the ionic compound. By containing at least one of these ionic compounds, excellent antistatic properties and peeling static properties can be imparted.

Since the alkali metal salt has high ion dissociation property, it is preferable in that it exhibits excellent antistatic ability even with a small amount of addition. Examples of the alkali metal salt include a cation consisting of ^{Li +} , Na ⁺ , and K ^{+ , Cl −} , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , and SCN. ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , C ₉ H ₁₉ COO ⁻ , CF ₃ COO ⁻ , C ₃ F ₇ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , C ₄ F ₉ SO ₃ ⁻ , C ₂ H ₅ OSO ₃ ⁻ , C ₆ H ₁₃ OSO ₃ ⁻ , C ₈ H ₁₇ OSO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (C ₃ F ₇ SO ₂ ) ₂ N ⁻ , (C ₄ F ₉ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , _{^{F (HF) n -, (}} CN) 2 n -, (CF 3 SO 2) (CF 3 CO) n -, (CH 3) 2 PO 4 -, (C 2 H 5) 2 PO 4 -, CH 3 (OC ₂ H ₄ ) ₂ OSO ₃ ⁻ , C ₆ H ₄ (CH ₃ ) SO ₃ ⁻ , (C ₂ F ₅ ) ₃ PF ₃ ⁻ , CH ₃ CH (OH) COO ⁻ , and (FSO ₂ ) ₂ A metal salt composed of an anion consisting of ^{N − is preferably used.} More preferably, LiBr, LiI, LiBF ₄ , LiPF ₆ , LiSCN, LiClO ₄ , LiCF ₃ SO ₃ , Li (CF ₃ SO ₂ ) ₂ N, Li (C ₂ F ₅ SO ₂ ) ₂ N, Li (FSO _{2) ) 2 N, Li (CF 3} SO 2) lithium salts such as ₃ C, more preferably _{LiCF 3 SO 3, Li (CF} 3 SO 2) 2 N, Li (C 2 F 5 SO 2) 2 N, Li ( C ₃ F ₇ SO ₂ ) ₂ N, Li (C ₄ F ₉ SO ₂ ) ₂ N, Li (FSO ₂ ) ₂ N, Li (CF ₃ SO ₂ ) ₃ C are used. These alkali metal salts may be used alone or in combination of two or more.

As the ionic liquid, one composed of an organic cation component represented by the following formulas (A) to (E) and an anion component is preferably used. By using an ionic liquid having a melting point of 100 ° C. or lower among these ionic liquids having cations, a liquid having further excellent antistatic ability can be obtained.

_Ra in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms, and may be a functional group in which a part of the hydrocarbon group is substituted with a heteroatom, and R _b and R _c. Represents hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, which may be the same or different, and may be a functional group in which a part of the hydrocarbon group is substituted with a heteroatom. However, when the nitrogen atom contains a double bond, there is no _{R c.}

R _d in the formula (B) represents a hydrocarbon group having from 2 to 20 carbon atoms, a part of the hydrocarbon group may be substituted by a functional group with a hetero atom, R _e, R _f , And _Rg may be the same or different, representing hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and may be a functional group in which a part of the hydrocarbon group is substituted with a heteroatom.

R _h in the formula (C) represents a hydrocarbon group having from 2 to 20 carbon atoms, a part of the hydrocarbon group may be substituted by a functional group with a hetero atom, R _i, R _j , And _Rk may be the same or different, representing hydrogen or a hydrocarbon group having 1 to 16 carbon atoms, and may be a functional group in which a part of the hydrocarbon group is substituted with a heteroatom.

Z in the formula (D) represents a nitrogen, sulfur, or phosphorus atom, and R _l , R _m , R _n , and _Ro represent the same or different hydrocarbon groups having 1 to 20 carbon atoms. , The functional group in which a part of the hydrocarbon group is substituted with a hetero atom may be used. However, when Z is a sulfur atom, there is no _Ro.

R _P in the formula (E) represents a hydrocarbon group having 1 to 18 carbon atoms, a part of the hydrocarbon group may be substituted by a functional group with a heteroatom.

Examples of the cation represented by the formula (A) include a pyridinium cation, a piperidinium cation, a pyrrolidinium cation, a cation having a pyrroline skeleton, a cation having a pyrrole skeleton, a morpholinium cation and the like.

Specific examples include, for example, 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-hexyl. -3-Methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1,1-dimethylpyrrolidinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidi Nium cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium Cation, 1-ethyl-1-propylpyrrolidinium cation, 1-ethyl-1-butylpyrrolidinium cation, 1-ethyl-1-pentylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation , 1-ethyl-1-heptylpyrrolidinium cation, 1,1-dipropylpyrrolidinium cation, 1-propyl-1-butylpyrrolidinium cation, 1,1-dibutylpyrrolidinium cation, pyrrolidinium-2 -On cation, 1-propylpiperidinium cation, 1-pentylpiperidinium cation, 1,1-dimethylpiperidinium cation, 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpi Peridinium cation, 1-methyl-1-butylpiperidinium cation, 1-methyl-1-pentylpiperidinium cation, 1-methyl-1-hexylpiperidinium cation, 1-methyl-1-heptylpiperidinium Nium cation, 1-ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation , 1-Ethyl-1-heptylpiperidinium cation, 1,1-dipropylpiperidinium cation, 1-propyl-1-butylpiperidinium cation, 1,1-dibutylpiperidinium cation, 2-methyl Examples include -1-pyrrolin cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, 1-ethylcarbazole cation, N-ethyl-N-methylmorpholinium cation and the like. Be done.

Examples of the cation represented by the formula (B) include an imidazolium cation, a tetrahydropyrimidinium cation, and a dihydropyrimidinium cation.

Specific examples include, for example, 1,3-dimethylimidazolium cation, 1,3-diethyl imidazolium cation, 1-ethyl-3-methyl imidazolium cation, 1-butyl-3-methyl imidazolium cation, 1-to. Xyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation Rium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3 -Dimethylimidazolium cation, 1- (2-methoxyethyl) -3-methylimidazolium cation, 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl- 1,4,5,6-Tetrahydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl- 1,4,5,6-Tetrahydropyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2, 3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidi Nium cations, 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cations and the like can be mentioned.

Examples of the cation represented by the formula (C) include a pyrazolium cation and a pyrazolinium cation.

Specific examples include, for example, 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2-methylpyrazolinium cation, 1-ethyl-2,3,5-trimethylpyrazolium cation. , 1-propyl-2,3,5-trimethylpyrazolium cation, 1-butyl-2,3,5-trimethylpyrazolium cation, 1-ethyl-2,3,5-trimethylpyrazolinium cation, 1 -Propyl-2,3,5-trimethylpyrazolinium cation, 1-butyl-2,3,5-trimethylpyrazolinium cation and the like can be mentioned.

Examples of the cation represented by the formula (D) include a tetraalkylammonium cation, a trialkylsulfonium cation, a tetraalkylphosphonium cation, and a part of the alkyl group is substituted with an alkenyl group, an alkoxyl group, or an epoxy group. There are things like epoxide.

Specific examples include, for example, tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, tetraheptylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation. , N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutyl Ethylsulfonium cation, dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation, diallyldimethyl Examples thereof include ammonium cation and tributyl- (2-methoxyethyl) phosphonium cation. Among them, asymmetrical ones such as triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation and trimethyldecylphosphonium cation. Tetraalkylammonium cation, trialkylsulfonium cation, tetraalkylphosphonium cation, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, diallyldimethylammonium cation, N, N -Dimethyl-N-ethyl-N-propylammonary cation, N, N-dimethyl-N-ethyl-N-butylammonary cation, N, N-dimethyl-N-ethyl-N-pentylammonary cation, N, N-dimethyl -N-ethyl-N-hexyl ammonium cation, N, N-dimethyl-N-ethyl-N-heptyl ammonium cation, N, N-dimethyl-N-ethyl-N-nonyl ammonium cation, N, N-dimethyl-N , N-dipropylammonary cation, N, N-diethyl-N-propyl-N-butylammonary cation, N, N-dimethyl-N-propyl-N-pentylammonary cation, N, N-dimethyl-N-propyl- N-hexylammonary cation, N, N-dimethyl-N-propyl-N-heptylammonium cation, N, N-dimethyl-N-butyl-N-hexylammonary cation, N, N-diethyl-N-butyl-N- Heptylammonium cation, N, N-dimethyl-N-pentyl-N-hexylammonium cation, N, N-dimethyl-N, N-dihexylammonium cation, trimethylheptylammonium cation, N, N-diethyl-N-methyl-N -Propylammonary cation, N, N-diethyl-N-methyl-N-pentylammonium cation, N, N-diethyl-N-methyl-N-heptylammonium cation, N, N-diethyl-N-propyl-N-pentyl Ammonium cation, triethylpropylammonary cation, triethylpentylammonium cation, triethylheptylammonium cation, N, N- Dipropyl-N-methyl-N-ethylammonium cation, N, N-dipropyl-N-methyl-N-pentylammonium cation, N, N-dipropyl-N-butyl-N-hexylammonium cation, N, N-dipropyl- N, N-dihexylammonium cation, N, N-dibutyl-N-methyl-N-pentylammonium cation, N, N-dibutyl-N-methyl-N-hexylammonium cation, trioctylmethylammonium cation, N-methyl- N-ethyl-N-propyl-N-pentylammonium cations are preferably used.

Examples of the cation represented by the formula (E) include a sulfonium cation and the like. Further, the formula Specific examples of R _P in (E) is a methyl group, an ethyl group, a propyl group, a butyl group, a hexyl group, an octyl group, nonyl group, decyl group, dodecyl group, tridecyl group, tetradecyl group, Examples thereof include an octadecyl group.

On the other hand, the anionic component is not particularly limited as long as it satisfies that it becomes an ionic liquid, for _{^{example, Cl -, Br -, I}} -, AlCl 4 -, Al 2 Cl 7 -, BF 4 -, PF ₆ ⁻ , SCN ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , C ₄ F ₉ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (C ₃ F ₇ SO ₂ ) ₂ N ⁻ , (C ₄ F ₉ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , F (HF) _n ⁻ , (CN) ₂ N ⁻ , C ₄ F ₉ SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , C ₃ F ₇ COO ⁻ , (CF ₃ SO ₂ ) (CF ₃ CO) N ⁻ , C ₉ H ₁₉ COO ⁻ , (CH ₃ ) ₂ PO ₄ ⁻ , (C ₂ H ₅ ) ₂ PO ₄ ⁻ , CH _{3 ^{OSO 3 -, C 2 H 5}} OSO 3 -, C 4 H 9 OSO 3 -, C 6 H 13 OSO 3 -, C 8 H 17 OSO 3 -, CH 3 (OC 2 H 4) 2 OSO 3 -, C ₆ H ₄ (CH ₃ ) SO ₃ ⁻ , (C ₂ F ₅ ) ₃ PF ₃ ⁻ , CH ₃ CH (OH) COO ⁻ , (FSO ₂ ) ₂ N ⁻ , B (CN) ₄ ⁻ , C (CN) _{^{3 -, N (CN) 2}} -, p- toluenesulfonate anion, can be used 2- (2-methoxyethyl) ethylsulfate anion.

These ionic liquids may be used alone or in combination of two or more.

なお、上記式（１）中のＲ_１〜Ｒ_４は、同一でも異なっていてもよく、炭素数１〜１０のアルキル基、アルコキシ基、アリール基、アリサイクリック基、フッ素置換アルキル基、イオン性基のいずれかを含み、Ｒ_１〜Ｒ_４のうち1つ以上にイオン性基を含む。ｎは０〜１００の整数である。 Further, as the ionic group-containing silicone, those represented by the following formula (1) are preferable.

_{R 1 to} R ₄ in the above formula (1) may be the same or different, and may be the same or different, as well as an alkyl group having 1 to 10 carbon atoms, an alkoxy group, an aryl group, an acyclic group, a fluorine-substituted alkyl group, and an ion. It contains any of the sex groups, and one or _{more of R 1 to} R ₄ contains an ionic group. n is an integer from 0 to 100.

Further, _{as the ionic group contained in one or more of R 1 to} R ₄ , an ammonium cation group or an ionic group having a phosphonium cation group is preferable. Among _{them, one or more of R 1 to} R ₄ is preferably composed of a cation structure represented by the following formula (a) or (b) and an anion component, or is represented by (c) or (d). It is preferably a zwitterionic structure.

上記式（ａ）中のＲ_５〜Ｒ_７は、同一でも異なっていてもよく、炭素数１〜１０のアルキル基、アリール基、フッ素置換アルキル基のいずれかを示す。ｍは１〜１０の整数である。

_{R 5 to} R ₇ in the above formula (a) may be the same or different, and represent any of an alkyl group having 1 to 10 carbon atoms, an aryl group, and a fluorine-substituted alkyl group. m is an integer of 1-10.

上記式（ｂ）中のＲ_８〜Ｒ_１０は、同一でも異なっていてもよく、炭素数１〜１０のアルキル基、アリール基、フッ素置換アルキル基のいずれかを示す。ｍは１〜１０の整数である。

_{R 8 to} R ₁₀ in the above formula (b) may be the same or different, and represent any of an alkyl group having 1 to 10 carbon atoms, an aryl group, and a fluorine-substituted alkyl group. m is an integer of 1-10.

On the other hand, the anion component is not particularly limited, and for example, Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , and so on. CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , C ₄ F ₉ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N _{^{-, (C 3 F 7 SO}} 2) 2 N -, (C 4 F 9 SO 2) 2 N -, (CF 3 SO 2) 3 C -, AsF 6 -, SbF 6 -, NbF 6 -, TaF 6 ⁻ , F (HF) _n ⁻ , (CN) ₂ N ⁻ , C ₄ F ₉ SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , C ₃ F ₇ COO ⁻ , (CF ₃ SO ₂ ) ( CF ₃ CO) N ⁻ , C ₉ H ₁₉ COO ⁻ , (CH ₃ ) ₂ PO ₄ ⁻ , (C ₂ H ₅ ) ₂ PO ₄ ⁻ , C ₂ H ₅ OSO ₃ ⁻ , C ₆ H ₁₃ OSO ₃ ⁻ , C ₈ H ₁₇ OSO ₃ ⁻ , CH ₃ (OC ₂ H ₄ ) ₂ OSO ₃ ⁻ , C ₆ H ₄ (CH ₃ ) SO ₃ ⁻ , (C ₂ F ₅ ) ₃ PF ₃ ⁻ , CH ₃ CH (OH) COO ⁻ and (FSO ₂ ) ₂ N ⁻ are used.

上記式（ｃ）中のＲ_１１、Ｒ_１２は、同一でも異なっていてもよく、炭素数１〜１０のアルキル基、アリール基、フッ素置換アルキル基のいずれかを示し、Ｒ_１１、Ｒ_１２は環を形成していてもよく、その場合はアルキレン基を表す。ｍは１〜１０の整数、ｐは１〜６の整数である。

_{R 11} and R ₁₂ in the above formula (c) may be the same or different, and represent any of an alkyl group having 1 to 10 carbon atoms, an aryl group, and a fluorine-substituted alkyl group, and R ₁₁ and R ₁₂ are It may form a ring, in which case it represents an alkylene group. m is an integer of 1 to 10, and p is an integer of 1 to 6.

上記式（ｄ）中のＲ_１３、Ｒ_１４は、同一でも異なっていてもよく、炭素数１〜１０のアルキル基、アリール基、フッ素置換アルキル基のいずれかを示し、Ｒ_１３、Ｒ_１４は環を形成してもよく、その場合はアルキレン基を表す。ｍは１〜１０の整数、ｐは１〜６の整数である。

_{R 13} and R ₁₄ in the above formula (d) may be the same or different, and represent any of an alkyl group having 1 to 10 carbon atoms, an aryl group, and a fluorine-substituted alkyl group, and R ₁₃ and R ₁₄ are A ring may be formed, in which case it represents an alkylene group. m is an integer of 1 to 10, and p is an integer of 1 to 6.

Since such an ionic group-containing silicone contains a silicone chain, the adhesive layer is attached to the surface of an adherend (for example, a polarizing plate) by the low surface free energy of the silicone chain and stored in a high temperature environment. Even in this case, the ionic group-containing silicone does not permeate into the adherend (from the surface of the adherend to the inside of the adherend) and tries to stay on the surface of the pressure-sensitive adhesive layer. Its characteristics are stable, its antistatic performance is maintained for a long period of time, and it can be suitably used as an antistatic agent.

Specific examples of the ionic group-containing silicone include commercially available product names X-40-2450 and X-40-2750 (all manufactured by Shin-Etsu Chemical Co., Ltd.). These compounds may be used alone or in combination of two or more.

The content of the ionic compound is based on 100 parts by mass of the adhesive polymer (base polymer, for example, (meth) acrylic polymer, urethane polymer, silicone polymer, etc.) constituting the pressure-sensitive adhesive composition. , 0.01 to 10 parts by mass, more preferably 0.02 to 7.5 parts by mass, still more preferably 0.03 to 5.5 parts by mass, and most preferably 0.04 to 4.8 parts by mass. It is a department. When it is within the above range, the pressure-sensitive adhesive sheet of the present invention is preferable because it is easy to achieve both antistatic properties and suppression of slippage (displacement).

<Oxyalkylene group-containing compound>
The pressure-sensitive adhesive composition of the present invention preferably contains an oxyalkylene group-containing compound, more preferably contains an organopolysiloxane having an oxyalkylene chain, and contains an organopolysiloxane having an oxyalkylene main chain. It is more preferable to do so. It is presumed that the use of the organopolysiloxane reduces the surface free energy of the adhesive surface and realizes light peeling.

なお、上記式（２）中、Ｒ_１及び／又はＲ_２は、炭素数１〜６のオキシアルキレン鎖を有し、前記オキシアルキレン鎖中のアルキレン基は、直鎖又は分岐していてもよく、前記オキシアルキレン鎖の末端が、アルコキシ基、又は、ヒドロキシル基であってもよい。また、Ｒ_１又はＲ_２のいずれか一方が、ヒドロキシル基でもよく、又は、アルキル基、アルコキシ基であってもよく、前記アルキル基、アルコキシ基の一部が、ヘテロ原子で置換された官能基であってもよい。ｎは、１〜３００の整数である。 As the organopolysiloxane, an organopolysiloxane having a known polyoxyalkylene main chain can be appropriately used, but it is preferably represented by the following formula (2).

In the above formula (2), R ₁ and / or R ₂ has an oxyalkylene chain having 1 to 6 carbon atoms, and the alkylene group in the oxyalkylene chain may be linear or branched. , The end of the oxyalkylene chain may be an alkoxy group or a hydroxyl group. Further, _{either R 1} or R ₂ may be a hydroxyl group, or an alkyl group or an alkoxy group, and a functional group in which a part of the alkyl group or the alkoxy group is substituted with a hetero atom. It may be. n is an integer from 1 to 300.

The organopolysiloxane has a siloxane-containing site (siloxane site) as the main chain, and an oxyalkylene chain bonded to the end of the main chain is used. It is presumed that by using the organosiloxane having the oxyalkylene chain, the compatibility with the (meth) acrylic polymer, the fluorine-based oligomer, the ionic compound, etc. is balanced, and light peeling is realized. ..

Further, as the organopolysiloxane in the present invention, for example, the following constitution can be used. Specifically, R ₁ and / or R ₂ in the formula has an oxyalkylene chain containing a hydrocarbon group having 1 to 6 carbon atoms, and the oxyalkylene chain includes an oxymethylene group, an oxyethylene group, and an oxy. Examples thereof include a propylene group and an oxybutylene group, and among them, an oxyethylene group and an oxypropylene group are preferable. When _{both R 1} and R ₂ have an oxyalkylene chain, they may be the same or different.

Further, the hydrocarbon group of the oxyalkylene chain may be linear or branched.

Further, the terminal of the oxyalkylene chain may be an alkoxy group or a hydroxyl group, but more preferably an alkoxy group. When a separator is attached to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the adhesive surface, an organopolysiloxane having a hydroxyl group at the end causes an interaction with the separator, and adhesion (peeling) when the separator is peeled off from the surface of the pressure-sensitive adhesive layer. Power may increase.

Further, n is an integer of 1 to 300, preferably 10 to 200, and more preferably 20 to 150. When n is within the above range, the compatibility with the base polymer is balanced, which is a preferable embodiment. Further, the molecule may have a reactive substituent such as a (meth) acryloyl group, an allyl group, or a hydroxyl group. The organopolysiloxane may be used alone or in combination of two or more.

Specific examples of the organopolysiloxane having an oxyalkylene chain in the main chain include, for example, commercially available products whose trade names are X-22-4952, X-22-2472, X-22-6266, KF-6004, and the like. Examples include KF-889 (above, manufactured by Shin-Etsu Chemical Co., Ltd.), BY16-201, SF8427 (above, manufactured by Toray Dow Corning), IM22 (manufactured by Asahi Kasei Wacker), and the like. These compounds may be used alone or in combination of two or more.

なお、上記式（３）中、Ｒ_１は１価の有機基、Ｒ_２，Ｒ_３及びＲ_４はアルキレン基、Ｒ_５は水素もしくは有機基、ｍ及びｎは０〜１０００の整数。但し、ｍ,ｎが同時に０となることはない。ａ及びｂは０〜１００の整数。但し、ａ, ｂが同時に０となることはない。) Further, in addition to the above-mentioned organosiloxane having (bonding) an oxyalkylene chain in the main chain, it is also possible to use an organosiloxane having (binding) an oxyalkylene chain in the side chain, and it is possible to use a side chain rather than the main chain. It is a more preferable embodiment to use an organosiloxane having an oxyalkylene chain. As the organopolysiloxane, an organopolysiloxane having a known polyoxyalkylene side chain can be appropriately used, but it is preferably represented by the following formula (3).

In the above formula (3), R ₁ is a monovalent organic group, R ₂ , R ₃ and R ₄ are alkylene groups, R ₅ is a hydrogen or organic group, and m and n are integers of 0 to 1000. However, m and n do not become 0 at the same time. a and b are integers from 0 to 100. However, a and b do not become 0 at the same time. )

Further, as the organopolysiloxane in the present invention, for example, the following constitution can be used. _{Specifically, R 1} in the formula is a monovalent group exemplified by an alkyl group such as a methyl group, an ethyl group or a propyl group, an aryl group such as a phenyl group or a tolyl group or an aralkyl group such as a benzyl group or a phenethyl group. It is an organic group and may have a substituent such as a hydroxyl group. R _{2, R 3} and _{R 4} may be used a methylene group, an ethylene group, an alkylene group having 1 to 8 carbon atoms such as a propylene group. Here, R ₃ and R ₄ are different alkylene groups, and R ₂ may be the same as _{or different from R 3} or R _4. R ₅ may be a monovalent organic group exemplified by an alkyl group such as a methyl group, an ethyl group or a propyl group or an acyl group such as an acetyl group or a propionyl group, and each has a substituent such as a hydroxyl group. May be. These compounds may be used alone or in combination of two or more. In addition, the molecule may have a reactive substituent such as a (meth) acryloyl group, an allyl group, or a hydroxyl group. Among the organosiloxanes having a polyoxyalkylene side chain, an organosiloxane having a polyoxyalkylene side chain having a hydroxyl group terminal is preferable because it is presumed that the compatibility is easily balanced.

Specific examples of the organosiloxane having an oxyalkylene chain on the side chain include commercially available products with trade names KF-351A, KF-352A, KF-353, KF-354L, KF-355A, KF-615A, and KF. -945, KF-640, KF-642, KF-643, KF-6022, X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, X-22 -2516 (all manufactured by Shin-Etsu Chemical Co., Ltd.) SF8428, FZ-2162, SH3749, FZ-77, L-7001, FZ-2104, FZ-2110, L-7002, FZ-2122, FZ-2164, FZ-2203 , FZ-7001, SH8400, SH8700, SF8410, SF8422 (all manufactured by Toray Dow Corning), TSF-4440, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4452, TSF-4460. (Manufactured by Momentive Performance Materials), BYK-333, BYK-307, BYK-377, BYK-UV3500, BYK-UV3570 (manufactured by Big Chemie Japan) and the like. These compounds may be used alone or in combination of two or more.

As the organosiloxane used in the present invention, the HLB (Hydrophile-Lipophilic Balance) value is preferably 1 to 16, and more preferably 3 to 14. If the HLB value is out of the above range, the contamination of the adherend becomes worse, which is not preferable.

The pressure-sensitive adhesive composition may contain an oxyalkylene group-containing compound that does not contain an organopolysiloxane. By containing the compound in the pressure-sensitive adhesive, it is possible to obtain a pressure-sensitive adhesive having further excellent wettability to the adherend.

Specific examples of the oxyalkylene group-containing compound containing no organopolysiloxane include polyoxyalkylene alkylamine, polyoxyalkylenediamine, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, and polyoxyalkylene alkylphenyl ether. , Polyoxyalkylene alkyl ether, polyoxyalkylene alkyl allyl ether, polyoxyalkylene alkyl phenyl allyl ether and other nonionic surfactants; polyoxyalkylene alkyl ether sulfate ester salt, polyoxyalkylene alkyl ether phosphate ester salt, poly Anionic surfactants such as oxyalkylene alkyl phenyl ether sulfate ester salts and polyoxyalkylene alkyl phenyl ether phosphate ester salts; in addition, cationic surfactants having a polyoxyalkylene chain (polyalkylene oxide chain) and amphoteric Examples thereof include a surfactant, a polyether compound having a polyoxyalkylene chain (including a derivative thereof), an acrylic compound having a polyoxyalkylene chain (including a derivative thereof), and the like. Further, the polyoxyalkylene chain-containing monomer may be blended as the polyoxyalkylene chain-containing compound. Such a polyoxyalkylene chain-containing compound may be used alone or in combination of two or more.

Specific examples of the polyether compound (polyether component) having a polyoxyalkylene chain include a block copolymer of polypropylene glycol (PPG) -polyethylene glycol (PEG), a block copolymer of PPG-PEG-PPG, and the like. Examples thereof include block copolymers of PEG-PPG-PEG. Examples of the derivative of the polyether compound having a polyoxyalkylene chain include an oxypropylene group-containing compound having an etherified terminal (PPG monoalkyl ether, PEG-PPG monoalkyl ether, etc.) and an oxypropylene having an acetylated terminal. Group-containing compounds (terminal acetylated PPG, etc.), and the like can be mentioned.

Further, specific examples of the acrylic compound having a polyoxyalkylene chain include a (meth) acrylate polymer having an oxyalkylene group. As the oxyalkylene group, the number of moles of the oxyalkylene unit added is preferably 1 to 50, more preferably 2 to 30, and even more preferably 2 to 20. Further, the terminal of the oxyalkylene chain may remain as a hydroxyl group or may be substituted with an alkyl group, a phenyl group or the like.

The (meth) acrylate polymer having an oxyalkylene group is preferably a polymer containing (meth) acrylate alkylene oxide as a monomer unit (component), and the specific embodiment of the (meth) acrylate alkylene oxide. As an example, examples of the ethylene glycol group-containing (meth) acrylate include methoxy-polyethylene glycol (meth) acrylate type such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) acrylate, and ethoxy-diethylene glycol ( Ethoxy-polyethylene glycol (meth) acrylate type such as meta) acrylate and ethoxy-triethylene glycol (meth) acrylate, butoxy-polyethylene glycol (meth) such as butoxy-diethylene glycol (meth) acrylate and butoxy-triethylene glycol (meth) acrylate. ) Acrylate type, phenoxy-polyethylene glycol (meth) acrylate type such as phenoxy-diethylene glycol (meth) acrylate, phenoxy-triethylene glycol (meth) acrylate, 2-ethylhexyl-polyethylene glycol (meth) acrylate, nonylphenol-polyethylene glycol (meth) ) Acrylate type, methoxy-polypropylene glycol (meth) acrylate type such as methoxy-dipropylene glycol (meth) acrylate and the like can be mentioned.

Further, as the monomer unit (component), other monomer units (components) other than the (meth) acrylic acid alkylene oxide can also be used. Specific examples of other monomer components include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, and isobutyl (meth). ) Acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) ) Acrylate and / or methacrylate having an alkyl group having 1 to 14 carbon atoms such as acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, and n-tetradecyl (meth) acrylate. Can be mentioned.

Further, as other monomer units (components) other than the (meth) acrylic acid alkylene oxide, a carboxyl group-containing (meth) acrylate, a phosphoric acid group-containing (meth) acrylate, a cyano group-containing (meth) acrylate, and vinyl esters , Aromatic vinyl compound, acid anhydride group-containing (meth) acrylate, hydroxyl group-containing (meth) acrylate, amide group-containing (meth) acrylate, amino group-containing (meth) acrylate, epoxy group-containing (meth) acrylate, N- Acryloylmorpholine, vinyl ethers and the like can also be used as appropriate.

In a more preferable aspect, the polyoxyalkylene chain-containing compound containing no organopolysiloxane is a compound having at least a part (poly) ethylene oxide chain. By blending the (poly) ethylene oxide chain-containing compound, the compatibility between the base polymer and the fluorine-based oligomer or the ionic compound is improved, bleeding to the adherend is suitably suppressed, and a low-staining pressure-sensitive adhesive is used. The composition is obtained. Above all, when a block copolymer of PPG-PEG-PPG is used, a pressure-sensitive adhesive having excellent low contamination property can be obtained. As the polyethylene oxide chain-containing compound, the weight of the (poly) ethylene oxide chain in the entire polyoxyalkylene chain-containing compound containing no organopolysiloxane is preferably 5 to 90% by mass, more preferably 5 to 85. It is by mass, more preferably 5 to 80% by mass, and most preferably 5 to 75% by mass.

As the molecular weight of the polyoxyalkylene chain-containing compound containing no organopolysiloxane, those having a number average molecular weight (Mn) of 50,000 or less are suitable, preferably 200 to 30,000, more preferably 200 to 10000, and usually. Is preferably 200 to 5000. If Mn is more than 50,000, the compatibility with the acrylic polymer is lowered and the pressure-sensitive adhesive layer tends to be whitened. If Mn is less than 200, contamination by the polyoxyalkylene compound may easily occur. Here, Mn means a polystyrene-equivalent value obtained by GPC (gel permeation chromatography).

Specific examples of the polyoxyalkylene chain-containing compound containing no organopolysiloxane as a commercial product include, for example, ADEKA PLRONIC 17R-4, ADEKA PLRONIC 25R-2 (all manufactured by ADEKA), and Latemul PD-. 420, Latemul PD-420, Latemul PD-450, Emargen 120 (manufactured by Kao), Aqualon HS-10, KH-10, Neugen EA-87, EA-137, EA-157, EA-167, EA-177 ( As mentioned above, (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and the like.

The content of the oxyalkylene group-containing compound is 100 parts by mass of the adhesive polymer (base polymer, for example, (meth) acrylic polymer, urethane polymer, silicone polymer, etc.) constituting the pressure-sensitive adhesive composition. It is preferably 0.01 to 5.0 parts by mass, more preferably 0.02 to 2 parts by mass, still more preferably 0.03 to 1.6 parts by mass, and most preferably 0.1 to 0. 8 parts by mass. When it is within the above range, the adhesive sheet of the present invention is preferable because it is easy to achieve both slippage (displacement) and light peelability (removability).

<Crosslinking agent>
In the pressure-sensitive adhesive sheet (surface protective film) of the present invention, it is preferable that the pressure-sensitive adhesive composition contains a cross-linking agent. Further, in the present invention, the pressure-sensitive adhesive composition can be used to form a pressure-sensitive adhesive layer. For example, when the pressure-sensitive adhesive composition is an acrylic pressure-sensitive adhesive containing the (meth) acrylic polymer, the constituent units, the constituent ratios, the selection and addition ratio of the cross-linking agent, etc. of the (meth) acrylic polymer are appropriately selected. By adjusting and cross-linking, an adhesive sheet (adhesive layer) having more excellent heat resistance can be obtained.

As the cross-linking agent used in the present invention, an isocyanate compound, an epoxy compound, a melamine resin, an aziridine derivative, a metal chelate compound and the like may be used, and the use of an isocyanate compound is particularly preferable. Further, these compounds may be used alone or in combination of two or more.

Examples of the isocyanate compound include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI) and dimerate diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate (IPDI), 1, Alicyclic isocyanates such as 3-bis (isocyanatomethyl) cyclohexane, aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate (XDI), and the isocyanate compounds. Examples thereof include polyisocyanate modified products modified by allophanate bond, biuret bond, isocyanurate bond, uretdione bond, urea bond, carbodiimide bond, uretonimine bond, oxadiazine trione bond and the like. For example, as commercial products, the trade names are Takenate 300S, Takenate 500, Takenate 600, Takenate D165N, Takeda D178N (all manufactured by Takeda Pharmaceutical Company Limited), Sumijour T80, Sumijour L, Death Module N3400 (above, Sumika Bayer Urethane). (Manufactured by Nippon Polyurethane Industry Co., Ltd.), Millionate MR, Millionate MT, Coronate L, Coronate HL, Coronate HX (all manufactured by Nippon Polyurethane Industry Co., Ltd.) and the like. These isocyanate compounds may be used alone or in combination of two or more, or a bifunctional isocyanate compound and a trifunctional or higher isocyanate compound may be used in combination. By using a cross-linking agent in combination, it is possible to achieve both adhesiveness and resilience (adhesiveness to a curved surface), and an adhesive sheet having more excellent adhesive reliability can be obtained.

When a bifunctional isocyanate compound and a trifunctional or higher functional isocyanate compound are used in combination as the isocyanate compound, the compounding ratio (mass ratio) of both compounds is [bifunctional isocyanate compound] / [3. The functional or higher isocyanate compound] (mass ratio) is preferably 0.1 / 99.9 to 50/50, more preferably 0.1 / 99.9 to 20/80, and 0.1 / 99. It is more preferably .9 to 10/90, more preferably 0.1 / 99.9 to 5/95, and most preferably 0.1 / 99.9 to 1/99. By adjusting and blending within the above range, a pressure-sensitive adhesive layer having excellent adhesiveness and resilience is obtained, which is a preferable embodiment.

Examples of the epoxy compound include N, N, N', N'-tetraglycidyl-m-xylene diamine (trade name: TETRAD-X, manufactured by Mitsubishi Gas Chemical Company, Inc.) and 1,3-bis (N, N-diamine). Glycidylaminomethyl) cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Company, Inc.) and the like can be mentioned.

Examples of the melamine-based resin include hexamethylol melamine. Examples of the aziridine derivative include commercially available commercial products such as HDU, TAZM, and TAZO (all manufactured by Mutual Pharmaceutical Co., Ltd.).

Examples of the metal chelate compound include aluminum, iron, tin, titanium, nickel and the like as metal components, and acetylene, methyl acetoacetate, ethyl lactate and the like as chelate components.

The content of the cross-linking agent used in the present invention is, for example, preferably 0.01 to 20 parts by mass and 0.1 to 15 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer. More preferably, it is more preferably 0.5 to 10 parts by mass, and most preferably 1 to 6 parts by mass. If the content is less than 0.01 parts by mass, the cross-linking by the cross-linking agent becomes insufficient, the cohesive force of the obtained pressure-sensitive adhesive layer becomes small, and sufficient heat resistance may not be obtained. It tends to cause adhesive residue. On the other hand, when the content exceeds 20 parts by mass, the cohesive force of the polymer is large, the fluidity is lowered, the wettability to the adherend (for example, the polarizing plate) is insufficient, and the adherend and the pressure-sensitive adhesive are used. It tends to cause blisters that occur between the layer (adhesive composition layer). Further, these cross-linking agents may be used alone or in combination of two or more.

The pressure-sensitive adhesive composition may further contain a cross-linking catalyst for more effectively advancing any of the above-mentioned cross-linking reactions. Examples of such cross-linking catalysts include tin-based catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris (acetylacetonato) iron (iron (III) acetylacetonate), and tris (hexane-2,4-dionat) iron. Tris (Heptane-2,4-Zionato) Iron, Tris (Heptan-3,5-Zionato) Iron, Tris (5-Methylhexane-2,4-Zionato) Iron, Tris (Octane-2,4-Zionato) Iron , Tris (6-methylheptane-2,4-Dionato) iron, Tris (2,6-dimethylheptane-3,5-Zionato) iron, Tris (Nonan-2,4-Dionato) iron, Tris (Nonan-4) , 6-Dionato) Iron, Tris (2,2,6,6-Tetramethylheptane-3,5-Zionato) Iron, Tris (Tridecane-6,8-Zionato) Iron, Tris (1-phenylbutane-1, 3-Dionato) iron, tris (hexafluoroacetylacetonato) iron, tris (ethylacetate acetate) iron, tris (acetoacetate-n-propyl) iron, tris (isopropylacetate isopropyl) iron, tris (acetoacetate-n-) Butyl) iron, tris (acetoacetate-sec-butyl) iron, tris (acetoacetate-tert-butyl) iron, tris (propionylmethylacetate) iron, tris (propionylacetate ethyl) iron, tris (propionylacetate-n-propyl) ) Iron, tris (isopropylacetic acid propionyl) iron, tris (propionylacetic acid-n-butyl) iron, tris (propionylacetic acid-sec-butyl) iron, tris (propionylacetic acid-tert-butyl) iron, tris (benzylacetate acetate) Iron-based catalysts such as iron, tris (dimethyl malonate) iron, tris (diethyl malonate) iron, trimethoxy iron, triethoxy iron, triisopropoxy iron, and ferric chloride can be used. These cross-linking catalysts may be used alone or in combination of two or more.

The content of the cross-linking catalyst is not particularly limited, but is preferably about 0.0001 to 1 part by mass, and 0.001 to 0.5 parts by mass, for example, with respect to 100 parts by mass of the (meth) acrylic polymer. Parts by mass are more preferred. When it is within the above range, the rate of the cross-linking reaction is high when the pressure-sensitive adhesive layer is formed, and the pot life of the pressure-sensitive adhesive composition is long, which is a preferable embodiment.

Further, the pressure-sensitive adhesive composition may contain a compound that causes keto-enol tautomerism. For example, in a pressure-sensitive adhesive composition containing a cross-linking agent or a pressure-sensitive adhesive composition that can be used by blending a cross-linking agent, an embodiment containing the compound that causes keto-enol tautomerization can be preferably adopted. As a result, the effect of suppressing an excessive increase in viscosity and gelation of the pressure-sensitive adhesive composition after blending the cross-linking agent and extending the pot life of the pressure-sensitive adhesive composition can be realized. When at least an isocyanate compound is used as the cross-linking agent, it is particularly meaningful to contain a compound that causes keto-enol tautomerism. This technique can be preferably applied, for example, when the pressure-sensitive adhesive composition is in the form of an organic solvent solution or a solvent-free form.

Various β-dicarbonyl compounds can be used as the compound that causes the keto-enol telecommunication. Specific examples include acetylacetone, 2,4-hexanedione, 3,5-heptandione, 2-methylhexane-3,5-dione, 6-methylheptane-2,4-dione, 2,6-dimethylheptane-. Β-diketones such as 3,5-dione; acetoacetate esters such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, tert-butyl acetoacetate; ethyl propionyl acetate, ethyl propionyl acetate, isopropyl propionyl acetate, propionyl acetate Propionyl acetates such as tert-butyl; isobutyryl acetates such as ethyl isobutyryl acetate, ethyl isobutyryl acetate, isopropyl isobutyryl acetate, tert-butyl isobutyryl acetate; malonic acid esters such as methyl malate and ethyl malonate; etc. Can be mentioned. Among them, acetylacetone and acetoacetic ester are examples of suitable compounds. The compound that causes such keto-enol tautomerism may be used alone or in combination of two or more.

The content of the compound that causes the keto-enol telecommunication can be, for example, 0.1 to 20 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer, and is usually 0.5 to 15 parts by mass. It is appropriate to use parts by mass (for example, 1 to 10 parts by mass). If the amount of the compound is too small, it may be difficult to exert a sufficient effect of use. On the other hand, if the compound is used in an unnecessarily large amount, it may remain in the pressure-sensitive adhesive layer and reduce the cohesive force.

Further, the pressure-sensitive adhesive composition may contain other known additives, for example, powders such as lubricants, colorants and pigments, plasticizers, pressure-sensitive adhesives, low-molecular-weight polymers and surface lubrication. Uses agents, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, UV absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powders, particles, foils, etc. It can be added as appropriate depending on the intended use.

<Adhesive layer and adhesive sheet (surface protective film)>
The pressure-sensitive adhesive sheet of the present invention is formed by forming the pressure-sensitive adhesive layer on at least one side of the base film. At that time, the pressure-sensitive adhesive composition is generally crosslinked after the pressure-sensitive adhesive composition is applied. However, it is also possible to transfer the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition after cross-linking to a base film or the like.

The method of forming the pressure-sensitive adhesive layer on the base film is not particularly limited. For example, the pressure-sensitive adhesive composition (solution) is applied to the base film, and a polymerization solvent or the like is dried and removed to form the pressure-sensitive adhesive layer. It is produced by forming it on a base film. After that, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer, adjusting the cross-linking reaction, and the like. Further, when the pressure-sensitive adhesive composition is applied onto the base film to prepare a pressure-sensitive adhesive sheet, one or more solvents other than the polymerization solvent may be contained in the pressure-sensitive adhesive composition so that the pressure-sensitive adhesive composition can be uniformly applied on the base film. May be newly added.

Further, as a method for forming the pressure-sensitive adhesive layer when manufacturing the pressure-sensitive adhesive sheet of the present invention, a known method used for manufacturing pressure-sensitive adhesive tapes is used. Specific examples thereof include a roll coat, a gravure coat, a reverse coat, a roll brush, a spray coat, an air knife coat method, and an extrusion coat method using a die coater or the like.

The pressure-sensitive adhesive sheet of the present invention is usually prepared so that the thickness of the pressure-sensitive adhesive layer is about 3 to 100 μm, preferably about 5 to 50 μm. When the thickness of the pressure-sensitive adhesive layer is within the above range, it is easy to obtain an appropriate balance between removability and adhesiveness, which is preferable.

The total thickness of the pressure-sensitive adhesive sheet of the present invention is preferably 8 to 300 μm, more preferably 10 to 200 μm, and most preferably 20 to 100 μm. When it is within the above range, it is excellent in adhesive properties (removability, adhesiveness, etc.), workability, and appearance characteristics, and is a preferable embodiment. The total thickness means the total thickness including all layers such as the base film, the pressure-sensitive adhesive layer, and other layers.

<Separator>
On the pressure-sensitive adhesive sheet of the present invention, it is preferable that the separator is attached to the surface of the pressure-sensitive adhesive layer opposite to the surface in contact with the base film. The separator can be attached to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive surface, if necessary.

Paper and a plastic film are examples of the material constituting the separator, and the plastic film is preferably used because of its excellent surface smoothness. The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer, and is, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, and a vinyl chloride co-weight. Examples thereof include a coalesced film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

The thickness of the separator is usually about 5 to 200 μm, preferably about 10 to 100 μm. When it is within the above range, it is preferable because it is excellent in sticking workability to the pressure-sensitive adhesive layer and peeling workability from the pressure-sensitive adhesive layer. If necessary, the separator may be used for mold release and antifouling treatment with a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based mold release agent, silica powder, etc., as well as a coating type, a kneading type, and a vapor deposition type. It is also possible to carry out antistatic treatment such as.

Further, in the pressure-sensitive adhesive sheet of the present invention, it is preferable that the fluorine-based oligomer is present (coated / laminated) on the surface of the separator in contact with the pressure-sensitive adhesive layer (see FIG. 1). The presence of the fluorine-based oligomer on the surface of the separator in contact with the pressure-sensitive adhesive layer allows the fluorine-based oligomer to be present on the pressure-sensitive adhesive layer from the surface of the separator when the separator is attached to the pressure-sensitive adhesive layer. After being transferred (transferred) to the surface and the adhesive layer is attached to an adherend (for example, a polarizing plate), it has a light peeling effect due to the low surface free energy of the fluorine portion and also functions as a tackifier resin. It is possible to improve the adhesiveness and suppress slipping (displacement), floating and peeling of the surface protective film (combining re-peelability and adhesiveness), which is a more preferable embodiment.

<Optical member>
When the adhesive sheet or the separator is attached, the optical member of the present invention is preferably attached (protected) by the adhesive sheet from which the separator has been peeled off. Since the adhesive sheet has excellent curl adjustability and light peelability, it can be used for surface protection applications (surface protection film) such as processing, transportation, and shipping, and thus protects the surface of the optical member (polarizing plate, etc.). Therefore, it becomes useful.

Hereinafter, some examples related to the present invention will be described, but the present invention is not intended to be limited to those shown in such specific examples. In addition, "part" and "%" in the following description are based on mass unless otherwise specified. In addition, the blending amount (addition amount) in the table is shown.

In addition, each characteristic in the following description was measured or evaluated as follows.

<Measurement of weight average molecular weight (Mw)>
The weight average molecular weight (Mw) of the polymer or the like used was measured using a GPC apparatus (HLC-8220 GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.
Sample concentration: 0.2% by mass (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow velocity: 0.6 ml / min
Measurement temperature: 40 ° C
column:
Sample column; TSKguardcolum SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column; TSKgel SuperH-RC (1)
Detector: Differential Refractometer (RI)
The weight average molecular weight was determined by polystyrene conversion value. Further, when measuring the number average molecular weight (Mn), it was measured in the same manner as the weight average molecular weight (Mw).

<Bubbling of adhesive composition (solution)>
After mixing and stirring the pressure-sensitive adhesive composition (solution) according to each example, foaming of the pressure-sensitive adhesive composition (solution) was visually observed. In the evaluation, the case where no bubbling was observed was evaluated as ◯, the case where bubbling was slightly observed was evaluated as Δ, and the case where bubbling was clearly observed was evaluated as ×.

<Shearing force>
After cutting the surface protective film into a size of 10 mm in width and 100 mm in length and peeling off the separator, a TAC polarizing plate (manufactured by Nitto Denko Co., Ltd., manufactured by Nitto Denko Co., Ltd.) so that ^{the adhesive area of the adhesive layer of the adhesive sheet becomes 1 cm 2.} It was attached to a SEG1423DU polarizing plate (width: 25 mm, length: 100 mm) and pulled in the shearing direction at a tensile speed of 0.06 mm / min at 23 ° C., and the maximum load (N / cm ² ) at that time was taken as the shearing force.

^{The surface protective film of the present invention preferably has a shearing force of 5 N / cm 2} or more with respect to the polarizing plate of the pressure-sensitive adhesive layer used for the surface protective film at 23 ° C. × 50% RH, and is 5 to 50 N / cm. ^{It is more preferably 2} and even more preferably 7 to 40 N / cm ² . By adjusting the shearing force to 5 N / cm ² or more, slipping (displacement), floating, peeling, etc. can be suppressed after the attachment to the adherend, and the curl adjustability is excellent, which is a preferable embodiment.

<Measurement of peeling band voltage>
The pressure-sensitive adhesive sheet 1 according to each example was cut into a size of 70 mm in width and 130 mm in length, the release liner (separator) was peeled off, and then a polarizing plate attached to the glass plate 10 (manufactured by Nitto Denko Corporation, SEG1423DU polarizing plate, width). : 70 mm, length: 100 mm) 20 was pressure-bonded with a hand roller so that one end of the pressure-sensitive adhesive sheet 1 protruded 30 mm from the end of the polarizing plate 20.
This sample was left to stand in an environment of 23 ° C. × 50% RH for one day, and then set in a predetermined position on a sample fixing base 30 having a height of 20 mm as shown in FIG. The end of the adhesive sheet (surface protective film) 1 protruding 30 mm from the polarizing plate 20 was fixed to an automatic winder (not shown) and peeled so as to have a peeling angle of 150 ° and a peeling speed of 30 m / min. The potential on the surface of the adherend (polarizing plate 20) generated at this time is fixed at a position 30 mm in height from the center of the polarizing plate 20. "), The" peeling band voltage "was measured. The measurement was performed in an environment of 23 ° C. and 50% RH.

The peeling band voltage (kV) (absolute value) in the present invention is preferably 1.0 or less, more preferably 0.5 or less, and further preferably 0.3 or less. When it is within the above range, it is excellent in antistatic property and peeling antistatic property, and further excellent in workability, which is a preferable embodiment.

<Presence / absence of contamination (contamination resistance)>
The adhesive sheet according to each example is cut into a size of 50 mm in width and 80 mm in length, the separator is peeled off, and then bubbles are applied to a TAC polarizing plate (manufactured by Nitto Denko, SEG1423DU polarizing plate, width: 70 mm, length: 100 mm). An evaluation sample was prepared by crimping with a hand roller while inserting. After the evaluation sample was left in an environment of 70 ° C. for 120 hours, the adhesive sheet was manually peeled off from the adherend, and the bubble traces on the surface of the adherend at that time were visually observed. In the evaluation, the case where no bubble trace was observed was evaluated as ◯, and the case where the bubble trace was observed was evaluated as x.

<Measurement of low-speed peeling force>
After leaving it in an environment of 23 ° C. × 50% RH for 24 hours, a surface protective film cut into a width of 25 mm and a length of 100 mm was formed into a TAC polarizing plate (manufactured by Nitto Denko, SEG1423DU polarizing plate, width: 70 mm, length: 100 mm) was laminated at a pressure of 0.25 MPa and a rate of 0.3 m / min to prepare an evaluation sample. After the above laminating, after leaving it in an environment of 23 ° C. × 50% RH for 30 minutes, a low-speed peeling force when peeling at a peeling speed of 0.3 m / min (low-speed peeling) and a peeling angle of 180 ° with a universal tensile tester. (N / 25 mm) was measured. The measurement was performed in an environment of 23 ° C. × 50% RH.

The surface protective film of the present invention has a 180 ° peel adhesive force (tensile speed 0.3 m / min: low-speed peeling force) at 23 ° C. × 50% RH with respect to the polarizing plate of the pressure-sensitive adhesive layer used for the surface protective film. It is preferably 0.15 N / 25 mm or less, more preferably 0.01 to 0.15 N / 25 mm, and even more preferably 0.02 to 0.14 N / 25 mm. By adjusting the peel adhesive force (tensile speed 0.3 m / min) to 0.15 N / 25 mm or less, peeling work becomes easy (removability) when the surface protective film becomes unnecessary, and adhesion is achieved. It is possible to prevent damage to the body and the like, which is a preferable embodiment.

<Preparation of acrylic polymer (1)>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler, 96 parts by mass of 2-ethylhexyl acrylate (2EHA), 4 parts by mass of 2-hydroxyethyl acrylate (HEA), and 2 as a polymerization initiator. , 2'-Azobisisobutyronitrile 0.2 parts by mass and ethyl acetate 150 parts by mass were charged, nitrogen gas was introduced with gentle stirring, and the liquid temperature in the flask was maintained at around 65 ° C. for 6 hours polymerization. The reaction was carried out to prepare an acrylic polymer (1) solution (40% by mass). The weight average molecular weight (Mw) of the acrylic polymer (1) was 540,000.

<Preparation of acrylic polymer (2)>
91 parts by mass of 2-ethylhexyl acrylate (2EHA), 9 parts by mass of 4-hydroxybutyl acrylate (4HBA), acrylic acid (AA) in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler. 0.02 parts by mass, 0.2 parts by mass of 2,2'-azobisisobutyronitrile and 150 parts by mass of ethyl acetate were charged as a polymerization initiator, nitrogen gas was introduced with gentle stirring, and the liquid in the flask was introduced. The polymerization reaction was carried out for 6 hours while keeping the temperature at around 65 ° C. to prepare an acrylic polymer (2) solution (40% by mass). The weight average molecular weight (Mw) of the acrylic polymer (2) was 540,000.

<Preparation of acrylic polymer (3)>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a cooler, 98.5 parts by mass of 2-ethylhexyl acrylate (2EHA) and 1.5 parts by mass of 4-hydroxybutyl acrylate (4HBA) were polymerized. Add 0.2 parts by mass of 2,2'-azobisisobutyronitrile and 150 parts by mass of ethyl acetate as an initiator, introduce nitrogen gas with gentle stirring, and keep the liquid temperature in the flask at around 65 ° C. The polymerization reaction was carried out for 6 hours to prepare an acrylic polymer (3) solution (40% by mass). The weight average molecular weight (Mw) of the acrylic polymer (3) was 550,000.

<Example 1>
[Preparation of acrylic adhesive solution]
The above acrylic polymer (1) solution (40% by mass) was diluted to 20% by mass with ethyl acetate, and 500 parts by mass (100 parts by mass of solid content) of this solution was added to a fluorine-based oligomer (Megafuck F-562, DIC). Is diluted to 10% with ethyl acetate (0.5 parts by mass), and LiTFSI as an ionic compound is diluted to 10% with ethyl acetate (5 parts by mass) (solid content 0.). 5 parts by mass), 3 parts by mass (3 parts by mass of solid content) of isocyanurate (Coronate HX, manufactured by Toso Co., Ltd.) of hexamethylene diisocyanate which is a trifunctional isocyanate compound as a cross-linking agent, and dibutyltin dilaurate (1 mass by mass) as a cross-linking catalyst. % Ethyl acetate solution) 3 parts by mass (solid content 0.03 parts by mass) was added, and the mixture was mixed and stirred to prepare an acrylic pressure-sensitive adhesive solution.

[Preparation of antistatic film]
Antistatic agent (manufactured by Solvex, microsolver RMd-142, mainly composed of tin oxide and polyester resin) 10 parts by mass is diluted with a mixed solvent consisting of 30 parts by mass of water and 70 parts by mass of methanol to prevent antistatic. A drug solution was prepared.
The obtained antistatic agent solution is applied onto a polyethylene terephthalate (PET) film (thickness: 38 μm) using a Meyer bar, and dried at 130 ° C. for 1 minute to remove the solvent to remove the antistatic layer (thickness). A: 0.2 μm) was formed to prepare an antistatic treated film.

[Preparation of adhesive sheet (surface protection film)]
The acrylic pressure-sensitive adhesive solution was applied to the surface of the antistatic treatment film opposite to the antistatic treatment surface, and heated at 130 ° C. for 2 minutes to form a pressure-sensitive adhesive layer having a thickness of 15 μm. Next, a silicone-treated surface of a polyethylene terephthalate film (thickness 25 μm) having been treated with silicone on one side was bonded to the surface of the pressure-sensitive adhesive layer to prepare a pressure-sensitive adhesive sheet.

<Examples 2 to 12>
An adhesive sheet was prepared in the same manner as in Example 1 according to the raw materials and blending amounts shown in Table 1.

<Example 13>
[Preparation of urethane adhesive solution]
As a polyol, Preminol S3011 (Mn = 10000, manufactured by Asahi Glass Co., Ltd.), which is a polyol having three hydroxyl groups, 85 parts by mass, and Sanniks GP3000 (Mn = 3000, manufactured by Sanyo Kasei Co., Ltd.), which is a polyol having three hydroxyl groups, 13 By mass, 2 parts by mass of Sanniks GP1000 (Mn = 1000, manufactured by Sanyo Kasei Co., Ltd.), which is a polyol having three hydroxyl groups, and 18 parts by mass of an isocyanate compound (Coronate HX: C / HX, manufactured by Nippon Polyurethane Co., Ltd.) as a cross-linking agent. As a catalyst, 0.04 parts by mass of iron (III) acetylacetonate (manufactured by Tokyo Kasei Kogyo Co., Ltd.), 0.2 parts by mass of megafuck F-562 (manufactured by DIC) of a fluorine-based oligomer, 1- as an ionic compound. 1 part by mass of ethyl-3-methylimidazolium tri (fluoromethanesulfonyl) imide (EMITFSI, manufactured by Tokyo Kasei Kogyo Co., Ltd.) and 210 parts by mass of ethyl acetate as a diluting solvent were added to obtain a urethane-based pressure-sensitive adhesive solution. Then, a pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 in which the heating conditions and the like and the thickness of the obtained pressure-sensitive adhesive layer were adjusted.

<Example 14>
[Preparation of silicone adhesive solution]
As a silicone-based pressure-sensitive adhesive, "X-40-3229" (solid content 60% by mass, manufactured by Shin-Etsu Chemical Co., Ltd.) is 100 parts by mass in solid content, and as a platinum catalyst, "CAT-PL-50T" (Shin-Etsu Chemical Co., Ltd.) (Manufactured by) 0.5 parts by mass, megafuck F-562 (manufactured by DIC) of fluorine-based oligomer, 0.2 parts by mass, 1-ethyl-3-methylimidazolium tri (fluoromethanesulfonyl) imide (EMITFSI) as an ionic compound , Tokyo Kasei Kogyo Co., Ltd.) 1 part by mass and 100 parts by mass of toluene as a solvent were blended to obtain a silicone-based pressure-sensitive adhesive solution. Then, a pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 in which the heating conditions and the like and the thickness of the obtained pressure-sensitive adhesive layer were adjusted.

<Comparative Examples 1 to 3>
An adhesive sheet was prepared in the same manner as in Example 1 according to the raw materials and blending amounts shown in Table 1.

Tables 1 and 2 show the above-mentioned compounding contents and the results of various measurements and evaluations on the pressure-sensitive adhesive sheets according to Examples and Comparative Examples. The blending amount in Table 1 indicates the active ingredient. Further, the abbreviations in Table 1 will be described below.

[Fluorine-based oligomer]
F-562: Fluorine-based oligomer, weight average molecular weight 27900, manufactured by DIC Corporation, trade name: Megafuck F-562
F-558: Fluorine-based oligomer, weight average molecular weight 11900, manufactured by DIC Corporation, trade name: Megafuck F-558
F-569: Fluorine-based oligomer, weight average molecular weight 6920, manufactured by DIC Corporation, trade name: Megafuck F-569
222F: Fluorine-based oligomer, weight average molecular weight 2940, manufactured by Neos, trade name: Futergent 222F

[Oxyalkylene group-containing compound]
PD-420: Organopolysiloxane-free oxyalkylene group-containing compound (HLB value: 12.6), manufactured by Kao Corporation, trade name: Latemul PD-420
KF-353: Organopolysiloxane containing oxyalkylene chain, manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-353

[Ionic compound]
LiTFSI: Lithium bis (trifluoromethanesulfonyl) imide, Bu ₃ MePTFSI manufactured by Tokyo Kasei Kogyo Co., Ltd .: Tributylmethylphosphonimbis (trifluoromethanesulfonyl) imide, manufactured by Tokyo Kasei Kogyo Co., Ltd. X-40-2450: Ionic group-containing silicone, Shinetsu BMPTFSI manufactured by Kagaku Co., Ltd .: 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, MTOATFSI manufactured by Wako Junyaku Co., Ltd .: Methyltrioctyl ammonium bis (trifluoromethanesulfonyl) imide, EMITFSI manufactured by Tokyo Kasei Kogyo Co., Ltd .: 1- Ethyl-3-methylimidazolium tri (fluoromethanesulfonyl) imide, manufactured by Tokyo Kasei Kogyo Co., Ltd.

From Table 2, it was confirmed that the shearing force and the peeling zone voltage were excellent in all the examples. Further, when the blending amount of the fluorine-based oligomer is adjusted to 5.5 parts by mass or less, which is excellent in stain resistance, with respect to 100 parts by mass of the polymer used, the stain resistance (low pollution resistance) is also obtained. It was confirmed that it was excellent. Further, in the case of the example using the fluorine-based oligomer having a weight average molecular weight of 20000 or more, it was confirmed that the foaming of the pressure-sensitive adhesive composition (solution) could be suppressed.

On the other hand, from Table 2, it was confirmed that in Comparative Example 1, since the ionic compound was not blended, the peeling zone voltage was inferior, and in Comparative Example 2, since the fluorine-based oligomer was not blended, the shearing force was inferior. Further, in Comparative Example 3, it was confirmed that the shearing force was inferior because the fluorine-based oligomer having a weight average molecular weight of less than 3500 was used. Further, in Comparative Example 3, since the fluorine-based oligomer 222F having a weight average molecular weight of less than 20000 was used, foaming of the pressure-sensitive adhesive composition (solution) was confirmed.

The adhesive sheet disclosed herein protects an optical member used as a component of a liquid crystal display panel, a plasma display panel (PDP), an organic electroluminescence (EL) display, or the like during manufacturing, transportation, or the like. It is suitable as a surface protective film for this purpose. In particular, a surface protective film (optical surface) applied to optical members such as polarizing plates (polarizing films) for liquid crystal display panels, wave plates, retardation plates, optical compensation films, brightness improving films, light diffusion sheets, and reflective sheets. It is useful as a protective film).

1: Adhesive sheet 10: Glass plate 11: Separator 12: Fluorine-based oligomer coating film 13: Adhesive layer 14: Base film 20: Polarizing plate 30: Sample fixing base 40: Potential measuring instrument

Claims (6)

It contains an adhesive polymer, a fluorine-based oligomer having a weight average molecular weight of 3500 or more, and an ionic compound.
The adhesive polymer is a (meth) acrylic polymer, and the adhesive polymer is a (meth) acrylic polymer.
A pressure-sensitive adhesive composition containing 0.01 to 0.1 parts by mass (excluding 0.1 parts by mass) of the fluorine-based oligomer with respect to 100 parts by mass of the pressure-sensitive adhesive polymer. The pressure-sensitive adhesive composition according to claim 1, wherein the pressure-sensitive adhesive composition contains an oxyalkylene group-containing compound. A pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition according to claim 1 or 2 is provided on at least one side of the base film.
A pressure-sensitive adhesive sheet in which the fluorine-based oligomer is present inside and / or on the surface of the pressure-sensitive adhesive layer. The pressure-sensitive adhesive sheet according to claim 3, wherein a separator is attached to the surface of the pressure-sensitive adhesive layer opposite to the surface in contact with the base film. The pressure-sensitive adhesive sheet according to claim 4, wherein the fluorine-based oligomer is present on the surface of the separator that comes into contact with the pressure-sensitive adhesive layer. An optical member, wherein the pressure-sensitive adhesive sheet according to claim 3 or the pressure-sensitive adhesive sheet obtained by peeling the separator from the pressure-sensitive adhesive sheet according to claim 4 or 5 is attached.

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