JP6704671B2 - Adhesive sheet and optical member - Google Patents

Description

The present invention relates to an adhesive sheet and an optical member.

The pressure-sensitive adhesive sheet of the present invention is a polarizing plate, a wavelength plate, a retardation plate, an optical compensation film, a reflection sheet, a brightness enhancement film, a cover glass, a cover sheet, a hard coat film used for liquid crystal displays, organic EL displays, touch panel displays and the like. , And is useful as a surface protective film used for the purpose of protecting the surface of an optical member such as transparent conductive glass and transparent conductive film.

2. Description of the Related Art In recent years, when transporting optical components and electronic components and mounting them on a printed circuit board, they have been transported in a state in which individual components are wrapped in a predetermined sheet or a state in which an adhesive tape is attached. Above all, the surface protective film is particularly widely used in the field of optical and electronic parts.

The surface protection film is generally attached to an adherend via an adhesive applied to the support film side, and is used for the purpose of preventing scratches and stains generated during processing and transportation of the adherend (Patent Document 1). ). 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. In these optical members, a surface protection film is attached via an adhesive to prevent scratches and stains that occur during processing and transportation of the adherend.

Then, this surface protection film is peeled and removed when it is no longer needed, but as the liquid crystal display panel becomes larger and thinner, damage to the polarizing plate and the liquid crystal cell tends to occur in the peeling process. In addition, it is required to have an appropriate adhesive force so that floating or the like does not occur at the time of peeling, and to have light peeling property and pickup property so as to enable re-peeling. Particularly, in recent years, along with the reduction in the thickness of displays, the optical members constituting the displays have also become thinner, and with optical members having a thickness of 150 μm or less, or even 100 μm or less, the optical members may bend during the transportation process. Therefore, it cannot be transported. There is also a problem that the optical member cannot be properly attached to another member. In order to avoid these problems, it has been made to suppress the deflection by thickening the surface protective film, but thickening causes heavy peeling, so the surface protective film should be removed when the surface protective film is no longer needed. When peeling off with a pickup tape, there is a problem that it can not be picked up. Therefore, there is a demand for a pressure-sensitive adhesive sheet that can be lightly peeled off and can be picked up so as to suppress the flexure and enable re-peeling.

JP, 2003-334911, A

Therefore, the present invention provides an adhesive sheet that can improve the adhesive property and the pickup property, and an optical member protected by the adhesive sheet, as a result of intensive studies in view of the above circumstances.

That is, the pressure-sensitive adhesive sheet of the present invention has a first resin layer, an adhesive layer, a second resin layer, and a pressure-sensitive adhesive layer formed from a pressure-sensitive adhesive composition in this order, and the first resin layer The value of the ratio of the thickness of the adhesive layer to the sum of the thickness of the resin layer and the thickness of the second resin layer is 0.50 or less, and the storage elastic modulus at 23° C. of the adhesive layer is 1.0× It is 10 ⁴ Pa or more and less than 5.0×10 ⁷ Pa, and the adhesive composition contains an alkylene oxide group-containing compound.

The pressure-sensitive adhesive sheet of the present invention has a topcoat layer on the surface opposite to the surface having the pressure-sensitive adhesive layer of the first resin layer, and the topcoat layer is a polyanilinesulfonic acid as a conductive polymer component, It is preferably formed from a composition for a topcoat layer containing a polyester resin as a binder component and an isocyanate compound as a crosslinking agent.

In the pressure-sensitive adhesive sheet of the present invention, it is preferable that the composition for the top coat layer further contains a fatty acid amide as a lubricant.

In the pressure-sensitive adhesive sheet of the present invention, at least one of the resin layers is preferably a polyester film.

In the pressure-sensitive adhesive sheet of the present invention, the pressure-sensitive adhesive composition preferably contains an acrylic pressure-sensitive adhesive and/or a urethane-based pressure-sensitive adhesive.

In the pressure-sensitive adhesive sheet of the present invention, it is preferable that the pressure-sensitive adhesive composition contains an antistatic component.

The optical member of the present invention is preferably protected by the pressure-sensitive adhesive sheet.

According to the pressure-sensitive adhesive sheet of the present invention, the pressure-sensitive adhesive sheet has a resin layer film in which a resin layer is laminated via an adhesive layer (the order of the first resin layer, the adhesive layer, and the second resin layer, which may be referred to as a laminated film). As a result, stress can be relieved in the adhesive layer portion against deformation when peeling the pressure-sensitive adhesive sheet, and it becomes possible to pick up with a lower peeling force (adhesive force) than the resin layer alone. In addition, the above-mentioned laminated structure makes it possible to improve the deflection amount of the laminated film (decrease the deflection amount) more than the deflection amount of each resin layer film, and improve the problem of conveyance failure due to bending or deformation in the conveyance process. It is possible to improve the manufacturing efficiency. Further, by having a pressure-sensitive adhesive layer containing a specific raw material, a pressure-sensitive adhesive sheet having excellent pressure-sensitive adhesive properties and pickup properties can be obtained, which is a preferred embodiment.

1 is a schematic sectional view of a protective film according to a preferred embodiment of the present invention. It is explanatory drawing which shows the measuring method of peeling electrification voltage. It is explanatory drawing which shows the measuring method of back surface adhesive force (A). It is explanatory drawing which shows the peeling method of the adhesive sheet which concerns on one Embodiment. It is explanatory drawing which shows the measuring method of the amount of deflection.

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

<Adhesive sheet (surface protection film)>
FIG. 1 is a schematic sectional view of an adhesive sheet according to a preferred embodiment of the present invention. The pressure-sensitive adhesive sheet 1 includes a first resin layer 6, an adhesive layer 7, and a second resin layer 8 (a configuration including a first resin layer, an adhesive layer, and a second resin layer in this order And a pressure-sensitive adhesive layer 20 in this order. Further, in addition to the above-mentioned structure, it is also a preferable embodiment to have a top coat layer 14 on the surface of the first resin layer 6 opposite to the surface having the pressure-sensitive adhesive layer 20. The pressure-sensitive adhesive sheet 1 is a layered product in which the first resin layer 6 and the second resin layer 8 are laminated via the adhesive layer 7, and further the pressure-sensitive adhesive layer 20 and the top coat layer 14 are provided. Preferably. In addition, the pressure-sensitive adhesive layer 20 is attached to an adherend (for example, an optical member). Although not shown, it is a preferred embodiment that a separator is attached to the surface of the pressure-sensitive adhesive layer 20 until it is attached to the adherend.

<Resin layer>
The resin layer is preferably composed of a resin film. The thickness of the resin layer is preferably 1 to 200 μm, more preferably 12 to 75 μm. The magnitude relationship between the thickness of the first resin layer and the thickness of the second resin layer is preferably (thickness of the first resin layer)≦(thickness of the second resin layer). In that case, The thickness of the resin layer is preferably 1 to 50 μm, more preferably 4 to 38 μm, most preferably 10 to 25 μm. The thickness of the second resin layer is preferably 10 to 200 μm, more preferably 25 to 130 μm, most preferably 38 to 75 μm. Within the above range, suppression of the amount of deflection of the pressure-sensitive adhesive sheet and pick-up property can both be achieved, which is a preferred embodiment.

The tensile strength in the MD direction (flow direction) of at least one of the resin layers can be set to any appropriate value. The MD layer (machine direction) tensile strength of the resin layer is preferably 90 to 350 MPa, more preferably 110 to 320 MPa, more preferably 130 to 300 MPa, and most preferably 180 to 250 MPa. Is. Within the above range, the amount of deflection of the pressure-sensitive adhesive sheet can be suppressed, which is a preferable mode.

In the technique disclosed herein, the resin material forming the resin layer (support/base material) can be used without particular limitation, and examples thereof include transparency, mechanical strength, thermal stability, and moisture shielding property. It is preferable to use a material having excellent properties such as isotropic property, flexibility, and dimensional stability. In particular, since the resin layer has flexibility, the pressure-sensitive adhesive composition can be applied by a roll coater or the like and can be wound into a roll, which is useful.

Examples of the resin layer include 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 polymers; polymethyl methacrylate and the like. A plastic film composed of a resin material containing an acrylic polymer; or the like as a main resin component (a main component among resin components, typically 50% by mass or more) is preferably used as the resin layer. it can. Other examples of the resin material include styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymer; olefin-based polymers such as polyethylene, polypropylene, polyolefin having a cyclic or norbornene structure, and ethylene-propylene copolymer; Examples of the resin material include vinyl chloride type polymers; amide type polymers such as nylon 6, nylon 6,6 and aromatic polyamides. As still another example of the resin material, an imide polymer, a sulfone polymer, a polyether sulfone polymer, a polyether ether ketone polymer, a polyphenylene sulfide polymer, a vinyl alcohol polymer, a vinylidene chloride polymer, a vinyl butyral polymer. , Arylate-based polymers, polyoxymethylene-based polymers, epoxy-based polymers and the like. It may be a resin layer composed of a blend of two or more kinds of the above-mentioned polymers.

Further, as the resin layer, a plastic film made of a transparent thermoplastic resin material can be preferably adopted. Among the plastic films, in the pressure-sensitive adhesive sheet of the present invention, at least one of the resin layers is polyester. A film is a more preferable embodiment. Here, the polyester film is a film whose main resin component is a 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. Such a polyester film has preferable properties as a resin layer of a pressure-sensitive adhesive sheet (surface protection film) such as excellent optical properties and dimensional stability, while it has a property of being easily charged as it is. Examples of the resin layer satisfying the tensile strength include the following resins. 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 polymers; acrylic polymers such as polymethyl methacrylate; polystyrene-based polymers A polyolefin having a cyclic or norbornene structure; an amide polymer such as nylon 6, nylon 6,6, aromatic polyamide; and the like as a main resin component (main component of the resin component, typically 50% by mass or more) A plastic film composed of a resin material as a component) can be preferably used as the resin layer. It may be a resin layer composed of a blend of two or more kinds of the above-mentioned polymers.

The resin material forming the resin layer may be mixed with various additives such as an antioxidant, an ultraviolet absorber, a plasticizer, and a coloring agent (pigment, dye, etc.), if necessary. The surface of the resin layer may be subjected to a known or common surface treatment such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and application of an undercoating agent. Such surface treatment may be, for example, a treatment for improving the adhesion between the resin layer and the pressure-sensitive adhesive layer, the top coat layer, or the like (such as anchoring property of the pressure-sensitive adhesive layer). A surface treatment in which a polar group such as a hydroxyl group is introduced on the surface of the resin layer can be preferably adopted.

The configurations of the first resin layer and the second resin layer (for example, thickness, forming material, elastic modulus, tensile elongation, etc.) may be the same or different, and can be appropriately selected.

<Adhesive layer>
The "adhesive layer" in the present invention means a layer in which the surfaces of adjacent resin layers are bonded to each other to be integrated with each other with practically sufficient adhesive force and adhesive time. Examples of the material forming the adhesive layer include a pressure-sensitive adhesive, an adhesive, and an anchor coating agent. The adhesive layer may have a multilayer structure in which an anchor coat layer is formed on the surface of the resin layer and the adhesive layer is formed thereon. The "adhesive layer" in the present invention means a layer that can be peeled (removable).

The value of the ratio of the thickness of the adhesive layer to the sum of the thickness of the first resin layer and the thickness of the second resin layer is 0.50 or less, preferably 0.4 or less, more preferably 0.35. Hereafter, it is most preferably 0.30 or less. By setting in such a range, it is possible to extremely well suppress the warp of the adherend (for example, the optical member). On the other hand, the value of the thickness ratio is preferably 0.03 or more. By setting it in such a range, the flexibility of the obtained pressure-sensitive adhesive sheet is more excellent, and extremely excellent releasability can be achieved.

The thickness of the adhesive layer is preferably thinner than the thickness of the resin layer. The difference between the thickness of the resin layer and the thickness of the adhesive layer is preferably 2 μm or more, more preferably 5 μm or more. If this difference is too small, the pickup property of the pressure-sensitive adhesive sheet may be insufficient depending on the thickness of the resin layer. The thickness of the adhesive layer is preferably 1 to 50 μm, more preferably 2 to 25 μm, and further preferably 5 to 20 μm. If the thickness of the adhesive layer is too thick, there is a possibility that a defect (for example, lack of glue) may occur in the formation of the adhesive layer.

According to the pressure-sensitive adhesive sheet of the present invention, stress can be relaxed by providing the adhesive layer, the peeling force of the obtained pressure-sensitive adhesive sheet can be reduced, and the pick-up property can be improved, and the peeling force lower than that of the resin layer alone. It becomes possible to do. Further, by having a resin layer film in which a resin layer is laminated via the adhesive layer (first resin layer, adhesive layer, second resin layer in this order), the amount of deflection of the laminated film is The amount of deflection can be improved (the amount of deflection can be reduced), the problem of conveyance failure due to bending or deformation in the conveyance process can be solved, and improvement in manufacturing efficiency can be achieved. The adhesive modulus of the adhesive layer at 23° C. is 1.0×10 ⁴ Pa or more and less than 5.0×10 ⁷ Pa, and preferably 1.0×10 ⁴ Pa or more and 1.0×10 ⁷ or more. It is less than Pa, and more preferably 1.0×10 ⁵ Pa or more and less than 1.0×10 ⁶ Pa. The storage elastic modulus of the adhesive layer is measured using a dynamic viscoelasticity measuring device under the condition of a frequency of 1 Hz.

The adhesive layer is typically formed of an adhesive. An acrylic adhesive is preferably used as the adhesive. The acrylic adhesive preferably contains a (meth)acrylic polymer and a crosslinking agent. The crosslinking agent is not particularly limited as long as it is a compound that reacts with the (meth)acrylic polymer, but an isocyanate compound, an epoxy compound, a melamine resin, an aziridine derivative, and a metal chelate compound are preferably used.

The (meth)acrylic polymer means a polymer or a copolymer synthesized from an acrylate monomer and/or a methacrylate monomer (herein referred to as (meth)acrylate). When the (meth)acrylic polymer is a copolymer, the arrangement state of the molecules is not particularly limited, and may be a random copolymer, a block copolymer, or a graft copolymer. It may be a united body. A preferable molecular arrangement state is a random copolymer. The polymerization method is not particularly limited, and known methods such as solution polymerization, emulsion polymerization, bulk polymerization and suspension polymerization can be used.

The (meth)acrylic polymer is obtained, for example, by homopolymerization or copolymerization of alkyl (meth)acrylate. The alkyl group of the alkyl (meth)acrylate may be linear, branched or cyclic. The alkyl group of the alkyl (meth)acrylate preferably has about 1 to 18 carbon atoms, more preferably 1 to 10 carbon atoms.

Specific examples of the alkyl(meth)acrylate include methyl(meth)acrylate, ethyl(meth)acrylate, propyl(meth)acrylate, n-butyl(meth)acrylate, iso-butyl(meth)acrylate, t-butyl( (Meth)acrylate, n-pentyl (meth)acrylate, iso-pentyl (meth)acrylate, n-hexyl (meth)acrylate, iso-hexyl (meth)acrylate, n-heptyl (meth)acrylate, iso-heptyl (meth) Acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, iso-octyl (meth)acrylate, n-nonyl (meth)acrylate, iso-nonyl (meth)acrylate, lauryl (meth)acrylate, stearyl ( Examples thereof include (meth)acrylate and cyclohexyl (meth)acrylate. These may be used alone or in combination of two or more.

The (meth)acrylic polymer is preferably a copolymer of the alkyl (meth)acrylate and a hydroxyl group-containing (meth)acrylate. In this case, the number of carbon atoms of the alkyl group of the alkyl (meth)acrylate is preferably 1-8, more preferably 2-8, even more preferably 2-6, and particularly preferably 4-6. The alkyl group of the alkyl (meth)acrylate may be linear or branched.

Specific examples of the hydroxyl group-containing (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 3-hydroxy-3-methylbutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 7- Examples thereof include hydroxyheptyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)-methyl acrylate. These may be used alone or in combination of two or more.

The number of carbon atoms of the hydroxyalkyl group of the hydroxyl group-containing (meth)acrylate is preferably smaller than that of the alkyl group of the alkyl (meth)acrylate. The number of carbon atoms of the hydroxyalkyl group of the hydroxyl group-containing (meth)acrylate is preferably 1-8, more preferably 2-4, and even more preferably 2. By adjusting the carbon number of the alkyl group in this way, the reactivity with the isocyanate compound described later can be improved, and an adhesive having even more excellent adhesive properties can be obtained.

The hydroxyl group-containing (meth)acrylate copolymerization amount is preferably 0.05 to 20 mol %, more preferably 0.10 to 8 mol %, further preferably 0.12 to 3 mol %, and even more preferably It is 0.14 to 1.5 mol %, and most preferably 0.14 to 0.25 mol %.

The (meth)acrylic polymer can be obtained by copolymerizing other components in addition to the alkyl (meth)acrylate and the hydroxyl group-containing (meth)acrylate. Other components are not particularly limited, but include (meth)acrylic acid, benzyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, phenoxyethyl (meth)acrylate, (meth)acrylamide, acetic acid. Vinyl and (meth)acrylonitrile are preferably used. The copolymerization amount of the other components is preferably 100 parts by mass or less, and more preferably 50 parts by mass or less with respect to 100 parts by mass of the alkyl (meth)acrylate.

The weight average molecular weight (Mw) of the (meth)acrylic polymer is preferably 400,000 or more, more preferably 1,000,000, as measured by a gel permeation chromatography (GPC) method using a tetrahydrofuran (THF) solvent. ˜3,000,000, particularly preferably 1.2,000,000 to 2,500,000.

Examples of the isocyanate compound include 2,4-(or 2,6-)tolylene diisocyanate, xylylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, hexamethylene diisocyanate, norbornene diisocyanate, chlorophenylene diisocyanate, tetramethylene. Isocyanate compounds such as diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, trimethylolpropane xylene diisocyanate and hydrogenated diphenylmethane diisocyanate; adduct isocyanate compounds obtained by adding these isocyanate monomers to polyhydric alcohols such as trimethylolpropane; isocyanurate compounds; burette Type compounds; further, urethane prepolymer type isocyanate obtained by addition reaction of any appropriate polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol, polyisoprene polyol, etc., and these are used alone or in combination. The above is used in combination.

As the isocyanate compound, a commercially available product can be used as it is. Examples of commercially available isocyanate compounds include Takenate series manufactured by Mitsui Takeda Chemical Co., Ltd. (trade name “D-110N,500,600,700”, etc.), Coronate series manufactured by Nippon Polyurethane Industry Co., Ltd. ( For example, the product name “L, MR, EH, HL”, etc.) can be mentioned.

Examples of the epoxy compound include N,N,N′,N′-tetraglycidyl-m-xylenediamine (trade name TETRAD-X, manufactured by Mitsubishi Gas Chemical Co., Inc.) and 1,3-bis(N,N-di). Glycidylaminomethyl)cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Co., Inc.) and the like.

Examples of the melamine-based resin include hexamethylolmelamine. Examples of the aziridine derivative include trade names HDU, TAZM, and TAZO (these are manufactured by Mutual Pharmaceutical Co., Ltd.).

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

The content of the crosslinking agent used in the present invention is, for example, preferably 0.1 to 10 parts by mass, and 0.2 to 4 parts by mass with respect to 100 parts by mass of the (meth)acrylic polymer. It is more preferably contained, even more preferably 0.3 to 1.5 parts by mass, still more preferably 0.4 to 0.9 parts by mass. With such a content, good adhesion can be obtained even under a harsh (high temperature, high humidity) environment. Further, these cross-linking agents may be used alone or in combination of two or more.

The acrylic adhesive (adhesive composition) preferably further contains a silane coupling agent and a radiation curable component. As the silane coupling agent, for example, one having any suitable functional group can be selected. Examples of the functional group include a vinyl group, an epoxy group, a methacryloxy group, an amino group, a mercapto group, an acryloxy group, an acetoacetyl group, an isocyanate group, a styryl group, and a polysulfide group. Specific examples of the silane coupling agent include vinyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane. Silane, γ-acryloxypropyltrimethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane, γ-aminopropylmethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis(triethoxysilylpropyl) tetrasulfide , Γ-isocyanatopropyltrimethoxysilane and the like. Among these, a silane coupling agent having an epoxy group is preferable, and γ-glydoxypropyltrimethoxysilane is more preferable.

As the silane coupling agent, a commercially available product can be used as it is. Examples of commercially available products include KA series (trade name "KA-1003" etc.), KBM series (trade names "KBM-303, KBM-403, KBM-503" etc.) and KBE series manufactured by Shin-Etsu Silicone Co., Ltd. (Trade name "KBE-402, KBE-502, KBE-903", etc.), SH series (trade name "SH6020, SH6040, SH6062", etc.) manufactured by Toray Industries, Inc. and SZ series (trade name "SZ6030, SZ6032," SZ6300" and the like).

The content of the silane coupling agent is preferably 0.001 to 2.0 parts by mass, more preferably 0.005 to 2.0 parts by mass with respect to 100 parts by mass of the (meth)acrylic polymer. %, more preferably 0.01 to 1.0 part by mass, and particularly preferably 0.02 to 0.5 part by mass. With such a content, peeling and generation of bubbles can be suppressed even in a harsh (high temperature, high humidity) environment.

As the radiation curable component, a monomer and/or oligomer component that undergoes radical polymerization or cationic polymerization by radiation is used. Examples of the monomer component that undergoes radical polymerization by radiation include a monomer having an unsaturated double bond such as a (meth)acryloyl group and a vinyl group. Particularly, a monomer having a (meth)acryloyl group is preferable because of its excellent reactivity. Used. Specific examples of the monomer component having a (meth)acryloyl group include allyl (meth)acrylate, caprolactone (meth)acrylate, cyclohexyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, and 2-ethylhexyl (meth). ) Acrylate, heptadecafluorodecyl (meth)acrylate, glycidyl (meth)acrylate, caprolactone-modified 2-hydroxylethyl (meth)acrylate, isobornyl (meth)acrylate, morpholine (meth)acrylate, phenoxyethyl (meth)acrylate, tri Propylene glycol di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, hydroxypivalic acid neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, trimethylolpropane ethoxytri(meth)acrylate, Pentaerythritol tri(meth)acrylate, pentaerythritol tetradipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, caprolactone modified dipentaerythritol hexa(meth)acrylate, etc. Can be mentioned.

As an oligomer component radically polymerized by radiation, polyester (epoxy, urethane, etc.) having two or more unsaturated double bonds such as (meth)acryloyl group and vinyl group as a functional group similar to the monomer component is added to the skeleton ( Meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, etc. are used.

The polyester (meth)acrylate is obtained by reacting (meth)acrylic acid with a polyester having a terminal hydroxyl group obtained from a polyhydric alcohol and a polycarboxylic acid, and specific examples include Aronix M- manufactured by Toagosei Co., Ltd. 6000, 7000, 8000, 9000 series polyester acrylates can be mentioned.

Epoxy (meth)acrylate is obtained by reacting (meth)acrylic acid with an epoxy resin, and specific examples thereof include Showa Polymer Co., Ltd.'s Lipoxy SP, VR series and Kyoeisha Chemical Co., Ltd.'s epoxy ester series epoxy acrylate. Is mentioned.

Urethane (meth)acrylate is obtained by reacting a polyol, an isocyanate and a hydroxy (meth)acrylate, and specific examples include Arte Resin UN series manufactured by Negami Kogyo Co., Ltd. and NK oligo U series manufactured by Shin Nakamura Chemical Co., Ltd. , Nippon Synthetic Chemical Industry Co., Ltd. purple UV series urethane acrylate.

A compound having a cationically polymerizable functional group such as an epoxy group, a hydroxyl group, a vinyl ether group, an episulfide, or an ethyleneimine group is used as the monomer and/or oligomer component to be cationically polymerized, and the epoxy group is particularly preferred because of its excellent reactivity. A compound having is used. Examples of the compound having an epoxy group include a polyhydric phenol compound or a glycidyl ether type epoxy resin produced by reacting a polyhydric alcohol with epichlorohydrin. Specifically, diglycidyl ether of bisphenol A or its alkylene oxide adduct, diglycidyl ether of bisphenol F or its alkylene oxide adduct, diglycidyl ether of hydrogenated bisphenol A or its alkylene oxide adduct, ethylene glycol diglycidyl ether. , Propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, butanediol diglycidyl ether, hexanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, polypropylene glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, pentaerythritol polyglycidyl ether Examples thereof include ether, sorbitol polyglycidyl ether, resorcin diglycidyl ether and the like.

These (meth)acrylic polymers and radiation-curable components are used in an appropriate combination, but if the compatibility (mixability) is poor, it becomes difficult to balance the adhesiveness and the storage elastic modulus after radiation curing. It is necessary to appropriately select a combination having a good compatibility, for example, because the light transmittance of the compound becomes poor. In particular, in applications where light transmittance is required, the total light transmittance after curing is adjusted to 85% or more (preferably 90% or more) and the haze value is 10 or less (preferably 5 or less). The amount of the radiation-curable component blended is appropriately adjusted depending on the storage elastic modulus and the adhesiveness after the radiation-curing, but generally 10 to 200 parts by mass, preferably 30 to 100 parts by mass of the tacky polymer. It is used in a proportion of 150 parts by mass.

The amount of the polyfunctional monomer used is appropriately selected depending on the balance with the (meth)acrylic polymer and the use as a pressure-sensitive adhesive sheet. In order to obtain sufficient heat resistance due to the cohesive force of the acrylic pressure-sensitive adhesive, it is generally preferable to add 0.1 to 30 parts by mass to 100 parts by mass of the (meth)acrylic polymer. Further, from the viewpoint of flexibility and adhesiveness, it is more preferable to add 10 parts by mass or less to 100 parts by mass of the (meth)acrylic polymer.

Examples of radiation include ultraviolet rays, laser rays, and α rays. Examples include β rays, γ rays, x rays, and electron rays, and ultraviolet rays are preferably used from the viewpoints of good controllability and handleability, and cost. More preferably, ultraviolet rays having a wavelength of 200 to 400 nm are used. Ultraviolet rays can be irradiated using an appropriate light source such as a high pressure mercury lamp, a microwave excitation type lamp, a chemical lamp or the like. When ultraviolet rays are used as radiation, a photopolymerization initiator is added to the acrylic adhesive.

The photopolymerization initiator may be a substance that generates a radical or a cation by irradiating with ultraviolet rays of an appropriate wavelength that can trigger the polymerization reaction, depending on the type of the radiation-reactive component, and photoradical polymerization initiation Examples of the agent include benzoin, benzoin methyl ether, benzoin ethyl ether, o-benzoylbenzoic acid methyl-p-benzoin ethyl ether, benzoin isopropyl ether, benzoins such as α-methylbenzoin, benzyl dimethyl ketal, trichloroacetophenone, and 2,2. -Acetophenones such as diethoxyacetophenone and 1-hydroxycyclohexyl phenyl ketone, propiophenones such as 2-hydroxy-2-methylpropiophenone and 2-hydroxy-4'-isopropyl-2-methylpropiophenone, and benzophenone , Benzophenones such as methylbenzophenone, p-chlorobenzophenone and p-dimethylaminobenzophenone, thioxanthones such as 2-chlorothioxanthone, 2-ethylthioxanthone and 2-isopropylthioxanthone, bis(2,4,6-trimethylbenzoyl)- Acylphosphine oxides such as phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyl)-(ethoxy)-phenylphosphine oxide, benzyl, dibenzosuberone, α- An acyl oxime ester etc. are mentioned. Examples of the photocationic polymerization initiator include onium salts such as aromatic diazonium salts, aromatic iodonium salts, and aromatic sulfonium salts, iron-allene complexes, titanocene complexes, organosilanol-aluminum complexes, and other organometallic complexes, nitrobenzyl. Examples thereof include esters, sulfonic acid derivatives, phosphoric acid esters, sulfonic acid derivatives, phosphoric acid esters, phenolsulfonic acid esters, diazonaphthoquinone and N-hydroxyimide sulfonates.

It is also possible to use two or more of the above photopolymerization initiators in combination. The photopolymerization initiator is usually added in an amount of 0.1 to 10 parts by mass, preferably 0.2 to 7 parts by mass, based on 100 parts by mass of the (meth)acrylic polymer.

It is also possible to use a photoinitiated polymerization aid such as amines in combination. Examples of the photoinitiator include 2-dimethylaminoethylbenzoate, dimethylaminoacetophenone, p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ester and the like. It is also possible to use two or more of the above photopolymerization initiation aids in combination. The polymerization initiation aid is preferably added in an amount of 0.05 to 10 parts by mass, more preferably 0.1 to 7 parts by mass, based on 100 parts by mass of the (meth)acrylic polymer.

<Lamination Method of First Resin Layer and Second Resin Layer>
Any appropriate method can be adopted as a method for laminating the first resin layer and the second resin layer. As a preferred embodiment, a method is used in which an adhesive layer is formed on one resin layer and the other resin layer is laminated on the adhesive layer. Any appropriate method can be adopted as the method for forming the adhesive layer. As a specific example, the adhesive layer can be formed by applying the adhesive (adhesive composition solution) to the resin layer and heating. Upon coating, it is preferable that the polymer concentration of the acrylic adhesive is appropriately adjusted by a solvent (eg, ethyl acetate or toluene). The heating temperature is preferably 20°C to 200°C, more preferably 50°C to 170°C.

The thickness of the above resin layer film (a structure having a first resin layer, an adhesive layer, and a second resin layer in this order) is preferably 11 to 230 μm, more preferably 50 to 110 μm.

<Adhesive layer>
The pressure-sensitive adhesive sheet of the present invention has the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer is formed from a pressure-sensitive adhesive composition, and as the pressure-sensitive adhesive composition, if it has adhesiveness, Can be used without restrictions. For example, an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, a polyester pressure-sensitive adhesive, a synthetic rubber pressure-sensitive adhesive, a natural rubber pressure-sensitive adhesive, a silicone pressure-sensitive adhesive, etc. can be used, and more preferably, an acrylic pressure-sensitive adhesive. Agent and/or urethane-based pressure-sensitive adhesive, and it is particularly preferable to use an acrylic-based pressure-sensitive adhesive using a (meth)acrylic polymer.

When the pressure-sensitive adhesive layer uses an acrylic pressure-sensitive adhesive, the (meth)acrylic polymer forming the acrylic pressure-sensitive adhesive has an alkyl group having 1 to 14 carbon atoms as a raw material monomer forming the pressure-sensitive adhesive (meth). ) Acrylic monomers can be used. As the (meth)acrylic monomer, one kind or two or more kinds can be used as a main component. By using the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms, it becomes easy to control the adhesive force to an adherend (protected object) to be low, and light releasability and re-peeling A pressure-sensitive adhesive sheet having excellent properties is obtained. The (meth)acrylic polymer in the present invention means an acrylic polymer and/or a methacrylic polymer, and the (meth)acrylate means an acrylate and/or a methacrylate.

Specific examples of the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms include, for example, 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( (Meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate and the like. Be done.

Among them, when the pressure-sensitive adhesive sheet of the present invention is used as a surface protective film, hexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, n-octyl(meth)acrylate, isooctyl(meth)acrylate, n-nonyl( Carbon such as (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate A (meth)acrylic monomer having an alkyl group of the number 6 to 14 is preferable. In particular, by using a (meth)acrylic monomer having an alkyl group having 6 to 14 carbon atoms, it becomes easy to control the adhesive force to an adherend to be low, and the removability becomes excellent.

In particular, it is preferable to contain 50% by mass or more of a (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms with respect to 100% by mass of the total amount of monomer components constituting the (meth)acrylic polymer. , More preferably 60 mass% or more, further preferably 70 mass% or more, and most preferably 80 to 93 mass %. When the amount is less than 50% by mass, the wettability of the pressure-sensitive adhesive composition and the cohesive force of the pressure-sensitive adhesive layer are deteriorated, 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 (meth)acrylic monomer having a hydroxyl group as a raw material monomer. As the (meth)acrylic monomer having a hydroxyl group, one type or two or more types can be used as a main component.

By using the (meth)acrylic monomer having a hydroxyl group, it becomes easy to control the crosslinking of the pressure-sensitive adhesive composition, and it is easy to control the balance between the improvement of wettability by flow and the reduction of the adhesive strength at the time of peeling. Become. Further, unlike a carboxyl group or a sulfonate group that can generally act as a crosslinking site, a hydroxyl group is, for example, an alkylene oxide group-containing compound that is an essential component, an ionic compound that is an antistatic component (antistatic agent), and the like. When used, since it has a suitable interaction, it can be preferably used in terms of antistatic property and pickup property.

Examples of the (meth)acrylic monomer having a hydroxyl group 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. Be done. Particularly, it is preferable to use a (meth)acrylic monomer having an alkyl group having a hydroxyl group having 4 or more carbon atoms because light peeling at high speed peeling is facilitated.

15 parts by mass or less of the (meth)acrylic monomer having a hydroxyl group is preferably contained, and more preferably 100 parts by mass of the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms. Is 1 to 13 parts by mass, more preferably 2 to 11 parts by mass, and most preferably 3.5 to 10 parts by mass. 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. Further, particularly by blending 5 parts by mass or more, it becomes easy to obtain an adhesive composition having good creep characteristics.

Further, as other polymerizable monomer components, Tg is set to 0° C. or lower (usually −100° C. or higher) for the reason that the adhesive performance is easily balanced, and the glass transition temperature or peeling of the (meth)acrylic polymer is controlled. A polymerizable monomer or the like for adjusting the properties can be used within a range that does not impair the effects of the present invention.

Examples of the polymerizable monomer other than the (meth)acrylic monomer having the alkyl group having 1 to 14 carbon atoms and the hydroxyl group-containing (meth)acrylic monomer used in the (meth)acrylic polymer Alternatively, a (meth)acrylic monomer having a carboxyl group can be used.

Examples of the (meth)acrylic monomer having a carboxyl group include (meth)acrylic acid, carboxylethyl(meth)acrylate, carboxylpentyl(meth)acrylate, 2-(meth)acryloyloxyethylhexahydrophthalic acid, 2-(meth)acryloyloxypropyl hexahydrophthalic acid, 2-(meth)acryloyloxyethyl phthalic acid, 2-(meth)acryloyloxyethyl succinic acid, 2-(meth)acryloyloxyethyl maleic acid, Examples thereof include carboxypolycaprolactone mono(meth)acrylate and 2-(meth)acryloyloxyethyl tetrahydrophthalic acid.

The (meth)acrylic monomer having a carboxyl group is preferably 5 parts by mass or less with respect to 100 parts by mass of the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms, and preferably 1 part by mass. It is more preferably not more than 0.2 parts by mass, further preferably less than 0.2 parts by mass, and most preferably not less than 0.01 parts by mass and less than 0.1 parts by mass. In particular, when a (meth)acrylic monomer having a carboxyl group is used in combination with a (meth)acrylic monomer having a hydroxyl group, it may be preferably used from the viewpoint that an adhesive composition having excellent creep properties can be obtained. is there. Further, when it exceeds 5 parts by mass, a large number of acid functional groups such as a carboxyl group having a large interaction are present, and when an ionic compound is blended as an antistatic component, the ionic compound contains an acid functional group such as a carboxyl group. The interaction between the two interferes with ionic conduction, lowers the conductivity efficiency, and may prevent sufficient antistatic properties from being obtained, which is not preferable. In order to achieve both the creep property and the light peeling property, the amount of the (meth)acrylic monomer having a hydroxyl group is 5 parts by mass or more and the (meth)acrylic monomer having a carboxyl group is 0 parts by mass. It is preferable that the content be 0.01% by mass or more and less than 0.1 parts by mass because both properties can be achieved.

Furthermore, the (meth)acrylic monomer having the alkyl group having 1 to 14 carbon atoms, the (meth)acrylic monomer having a hydroxyl group, and the carboxyl group (meth) used in the (meth)acrylic polymer. Any polymerizable monomer other than the acrylic monomer can be used without particular limitation as long as it does not impair the characteristics of the present invention. For example, cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers and other cohesive strength/heat resistance improving components, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, N-acryloylmorpholine. A component having a functional group such as a vinyl ether monomer which improves the adhesive strength or acts as a cross-linking base point can be appropriately used. These polymerizable monomers may be used alone or in combination of two or more.

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

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 amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, N,N-diethylmethacryl. Examples thereof include amide, N,N'-methylenebisacrylamide, N,N-dimethylaminopropyl acrylamide, N,N-dimethylaminopropyl methacrylamide, and diacetone acrylamide.

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

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

Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate, methylglycidyl (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 (meth)acrylic monomer having a hydroxyl group, and the (meth)acrylic monomer having a carboxyl group are The amount is preferably 0 to 40 parts by mass, and more preferably 0 to 30 parts by mass, relative to 100 parts by mass of the (meth)acrylic monomer having an alkyl group having 1 to 14 carbon atoms. When the other polymerizable monomer is used within the above range, when an ionic compound is used as the antistatic agent, good interaction with the ionic compound and good removability can be appropriately adjusted. ..

The weight average molecular weight (Mw) of the (meth)acrylic polymer is preferably 100,000 to 5,000,000, more preferably 200,000 to 2,000,000, and further preferably 300,000 to 1,000,000. When the weight average molecular weight is less than 100,000, adhesive strength tends to occur due to a decrease in cohesive force of the pressure-sensitive adhesive layer. On the other hand, when the weight average molecular weight is more than 5,000,000, the fluidity of the polymer is lowered and the adherend (for example, a polarizing plate) is insufficiently wetted, so that the adherend and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet are separated from each other. It tends to cause blisters that occur between. In addition, a weight average molecular weight says what was obtained by measuring by gel permeation chromatography (GPC).

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, and for example, the wetting of the polarizing plate becomes insufficient, which tends to cause blistering between the polarizing plate and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet. is there. In particular, by setting the glass transition temperature to -61°C or lower, it becomes easy to obtain a pressure-sensitive adhesive layer having excellent wettability to a polarizing plate and light peeling property. The glass transition temperature of the (meth)acrylic polymer can be adjusted within the above range by appropriately changing the monomer components used and the composition ratio.

The method for polymerizing the (meth)acrylic polymer is not particularly limited, and it can be polymerized by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization, etc. Solution polymerization is a more preferable embodiment from the viewpoint of characteristics such as low contamination to the adherend (object to be protected). Further, the obtained polymer may be any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer and the like. Further, the polymerization conditions, the polymerization solvent, the polymerization initiator and the like can be appropriately used based on known techniques.

When the pressure-sensitive adhesive layer uses a urethane-based pressure-sensitive adhesive, any appropriate urethane-based pressure-sensitive adhesive can be adopted as the urethane-based pressure-sensitive adhesive. As such a urethane-based pressure-sensitive adhesive, preferably, a urethane-based adhesive obtained by reacting a polyol with a polyisocyanate compound is used. Examples of the polyol include polyether polyol, polyester polyol, polycarbonate polyol, polycaprolactone polyol and the like. Examples of the polyisocyanate compound include diphenylmethane diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, and the like.

The pressure-sensitive adhesive composition is characterized by containing an alkylene oxide (AO) group-containing compound. By containing the compound in the pressure-sensitive adhesive, a pressure-sensitive adhesive having excellent wettability to an adherend can be obtained, and the pickup property can be further improved.

Specific examples of the alkylene oxide (AO) group-containing compound include, for example, polyoxyalkylene alkylamine, polyoxyalkylene diamine, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene alkylphenyl ether, and polyoxy. Nonionic surfactant such as alkylene alkyl ether, polyoxyalkylene allyl ether, polyoxyalkylene alkyl allyl ether, polyoxyalkylene alkylphenyl allyl ether, polyalkylene glycol dialkyl ester, polyalkylene glycol diaryl ester; polyoxyalkylene alkyl ether Sulfate ester salt, polyoxyalkylene allyl ether sulfate ester salt, polyoxyalkylene alkyl ether phosphate ester salt, polyoxyalkylene alkyl phenyl ether sulfate ester salt, polyoxyalkylene alkyl allyl phenyl ether sulfate ester salt, polyoxyalkylene alkyl phenyl ether Anionic surfactants such as phosphate ester salts; Others, cationic surfactants having a polyoxyalkylene chain (polyalkylene oxide chain), amphoteric surfactants, polyether compounds having a polyoxyalkylene chain (and Examples thereof include a derivative thereof), an ester compound having a polyoxyalkylene chain (and a derivative thereof), an acrylic compound having a polyoxyalkylene chain (and a derivative thereof), and the like. Moreover, you may mix|blend a polyoxyalkylene chain containing monomer with an acrylic polymer as a polyoxyalkylene chain containing compound. Such polyoxyalkylene chain-containing compounds may be used alone or in combination of two or more.

Specific examples of the ether compound having a polyoxyalkylene chain include polypropylene glycol (PPG)-polyethylene glycol (PEG) block copolymers, PPG-PEG-PPG block copolymers, and PEG-PPG-PEG blocks. Examples thereof include copolymers. Examples of the derivative of the ether 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 group having an acetylated terminal. Examples thereof include compounds (terminally acetylated PPG, etc.), and the like. Specific examples of the ester compound having a polyoxyalkylene chain include ester compounds having an oxyalkylene group. As the oxyalkylene group, the number of added oxyalkylene units is preferably 1 to 50, more preferably 2 to 30, and even more preferably 2 to 20 from the viewpoint of coordination of the ionic compound. Specific examples include diethylene glycol dibenzoate, triethylene glycol dibenzoate, tetraethylene glycol dibenzoate, polyethylene glycol dibenzoate, polypropylene glycol dibenzoate, polyethylene glycol-2-ethylhexonate benzoate, and the like.

Specific examples of the acrylic compound having a polyoxyalkylene chain include (meth)acrylate polymers having an oxyalkylene group. As the oxyalkylene group, the number of added oxyalkylene units is preferably 1 to 50, more preferably 2 to 30, and even more preferably 2 to 20 from the viewpoint of coordination of the ionic compound. The terminal of the oxyalkylene chain may be a hydroxyl group as it is, 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)acrylic acid alkylene oxide as a monomer unit (component), and specific examples of the (meth)acrylic acid alkylene oxide include Examples of the ethylene glycol group-containing (meth)acrylate include, for example, methoxy-diethylene glycol (meth)acrylate, methoxy-polyethylene glycol (meth)acrylate type such as methoxy-triethylene glycol (meth)acrylate, ethoxy-diethylene glycol (meth). Acrylate, ethoxy-polyethylene glycol (meth)acrylate type such as ethoxy-triethylene glycol (meth)acrylate, butoxy-polyethylene glycol (meth)acrylate such as butoxy-diethylene glycol (meth)acrylate, butoxy-triethylene glycol (meth)acrylate Type, phenoxy-polyethylene glycol (meth)acrylate such as phenoxy-diethylene glycol (meth)acrylate, phenoxy-triethylene glycol (meth)acrylate, 2-ethylhexyl-polyethylene glycol (meth)acrylate, nonylphenol-polyethylene glycol (meth)acrylate And methoxy-polypropylene glycol (meth)acrylate type such as methoxy-dipropylene glycol (meth)acrylate.

Further, as the monomer unit (component), other monomer unit (component) other than the (meth)acrylic acid alkylene oxide can 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, 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, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate, n-tridecyl (meth)acrylate, n-tetradecyl (meth)acrylate, and other acrylates and/or methacrylates having an alkyl group having 1 to 14 carbon atoms. Is mentioned.

Furthermore, as the other monomer unit (component) 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, a vinyl ester, an aromatic Group 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 It is also possible to appropriately use vinyl ethers and the like.

In a more preferred embodiment, the alkylene oxide group-containing compound is a compound having a (poly)ethylene oxide chain at least in part. By blending the (poly)ethylene oxide chain-containing compound, the compatibility between the base polymer and the antistatic component is improved, bleeding to the adherend is suitably suppressed, and a low-staining pressure-sensitive adhesive composition is obtained. Be done. Above all, when a PPG-PEG-PPG block copolymer is used, a pressure-sensitive adhesive excellent in low stain resistance can be obtained. As the polyethylene oxide chain-containing compound, the weight of the (poly)ethylene oxide chain in the whole alkylene oxide group-containing compound is preferably 5 to 90% by mass, more preferably 10 to 85% by mass, and further preferably 20. -80 mass %, most preferably 45-75 mass %.

The number average molecular weight (Mn) of the alkylene oxide group-containing compound is suitably 50,000 or less, preferably 200 to 30,000, more preferably 200 to 10,000, and usually 200 to 5,000. Used. If Mn is too large 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 with the polyoxyalkylene compound may easily occur. In addition, here, Mn means a polystyrene conversion value obtained by gel permeation chromatography (GPC).

Specific examples of the alkylene oxide group-containing compound as a commercially available product include, for example, ADEKA Pluronic 17R-2, ADEKA Pluronic 17R-3, ADEKA Pluronic 17R-4, ADEKA Pluronic 25R-1, and ADEKA Pluronic 25R-2 (or more. , All manufactured by ADEKA), Emulgen 120 (manufactured by Kao), AQUARON HS-10 (manufactured by Daiichi Kogyo Co., Ltd.), AQUARON KH-10 (manufactured by Daiichi Kogyo Yakuhin), Neugen ES-99D (Daiichi Kogyo). Chemicals Co., Ltd.), DKS-NL-30 (Daiichi Kogyo Chemicals Co., Ltd.), Sunflex EB-400 (Sanyo Kasei Kogyo Co., Ltd.), and the like.

The compounding amount of the alkylene oxide group-containing compound may be, for example, 0.005 to 20 parts by mass, preferably 0.01 to 15 parts by mass, and more preferably 0, with respect to 100 parts by mass of the acrylic polymer. 0.05 to 10 parts by mass, most preferably 0.1 to 4 parts by mass. If the blending amount is too small, the effect of preventing bleeding of the antistatic component is reduced, and if the blending amount is too large, contamination with the polyoxyalkylene compound easily occurs, and when joining other members to the adherend after peeling the pressure-sensitive adhesive sheet. Poor adhesion can occur.

In addition, particularly in applications requiring adhesiveness when joining other members to an adherend after peeling the adhesive sheet, the following compounds can be preferably used as the alkylene oxide group-containing compound. For example, polyoxyalkylene alkylamine, polyoxyalkylene diamine, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene alkyl phenyl ether, polyoxyalkylene alkyl ether, polyoxyalkylene allyl ether, polyoxyalkylene alkyl allyl Ether, polyoxyalkylene alkyl phenyl allyl ether, polyalkylene glycol dialkyl ester, polyalkylene glycol diaryl ester, polyoxyalkylene alkyl ether sulfate ester salt, polyoxyalkylene allyl ether sulfate ester salt, polyoxyalkylene alkyl ether phosphate ester salt, Polyoxyalkylene alkyl phenyl ether sulfate ester salt, polyoxyalkylene alkyl allyl phenyl ether sulfate ester salt, polyoxyalkylene alkyl phenyl ether phosphate ester salt, polypropylene glycol (PPG)-polyethylene glycol (PEG) block copolymer, PPG An ether compound having a polyoxyalkylene chain such as a block copolymer of PEG-PPG and a block copolymer of PEG-PPG-PEG, an oxypropylene group-containing compound having an etherified terminal (PPG monoalkyl ether, PEG- PPG monoalkyl ether, etc.), derivatives of ether compounds having a polyoxyalkylene chain, such as acetylated terminal oxypropylene group-containing compounds (terminally acetylated PPG, etc.), diethylene glycol dibenzoate, triethylene glycol dibenzoate, tetraethylene Ester compounds (including derivatives thereof) having a polyoxyalkylene chain such as glycol dibenzoate, polyethylene glycol dibenzoate, polypropylene glycol dibenzoate, and polyethylene glycol-2-ethylhexonate benzoate, acryl having a polyoxyalkylene chain Examples thereof include compounds (including derivatives thereof) and the like.

<Antistatic component in adhesive layer>
In the pressure-sensitive adhesive sheet of the present invention, the pressure-sensitive adhesive composition forming the pressure-sensitive adhesive layer preferably contains an antistatic component, and more preferably contains an ionic compound as the antistatic component. Examples of the ionic compound include an alkali metal salt and/or an ionic liquid having a melting point of 100° C. or lower. By containing these ionic compounds, excellent antistatic properties can be imparted. The pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition containing the antistatic component as described above (using the antistatic component) is an adherend that is not antistatic when peeled (for example, a polarizing plate. ) Is prevented, and the pressure-sensitive adhesive sheet has reduced contamination on the adherend. Therefore, it is very useful as an antistatic pressure-sensitive adhesive sheet in the technical field related to optical/electronic parts in which charging and contamination are particularly serious problems.

The content of the antistatic component is preferably 4.9 parts by mass or less, more preferably 0.001 to 0.9 part by mass, and more preferably 100 parts by mass of the (meth)acrylic polymer. The amount is 0.005 to 0.8 parts by mass, and most preferably 0.01 to 0.6 parts by mass. Within the above range, it is easy to achieve both antistatic property and low contamination property, which is preferable.

<Crosslinking agent>
In the pressure-sensitive adhesive sheet of the present invention, it is preferable that the pressure-sensitive adhesive composition contains a crosslinking agent. In the present invention, the pressure-sensitive adhesive composition can be used to form a pressure-sensitive adhesive layer. For example, in the case where the pressure-sensitive adhesive contains the (meth)acrylic polymer, by appropriately adjusting the constitutional unit of the (meth)acrylic polymer, the constitutional ratio, the selection and addition ratio of the crosslinking agent, etc. A pressure-sensitive adhesive sheet (pressure-sensitive 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, or the like may be used, and the use of the isocyanate compound is a preferred embodiment. These compounds may be used alone or in combination of two or more.

Examples of the isocyanate compound (isocyanate-based crosslinking agent) include trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), aliphatic polyisocyanates such as dimer acid diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate. Alicyclic isocyanates such as (IPDI), 2,4-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, aromatic isocyanates such as xylylene diisocyanate (XDI), allophanate bond, biuret bond, and the above isocyanate compound. Examples thereof include modified polyisocyanate modified by isocyanurate bond, uretdione bond, urea bond, carbodiimide bond, uretonimine bond, oxadiazinetrione bond and the like. For example, as commercially available products, trade name Takenate 300S, Takenate 500, Takenate D165N, Takenate D178N (Takeda Pharmaceutical Co., Ltd.), Sumidule T80, Sumidule L, Death Module N3400 (above, Sumika Bayer Urethane Co., Ltd.) , Millionate MR, Millionate MT, Coronate L, Coronate HL, Coronate HX (above, manufactured by Nippon Polyurethane Industry Co., Ltd.) and the like. These isocyanate compounds may be used alone or in combination of two or more, and it is also possible to use a bifunctional isocyanate compound and a trifunctional or higher functional isocyanate compound in combination. By using a cross-linking agent in combination, both tackiness and repulsion resistance (adhesion to curved surface) can be achieved, and a pressure-sensitive adhesive sheet with more excellent adhesion reliability can be obtained.

Further, when the above-mentioned isocyanate compound (a bifunctional isocyanate compound and a trifunctional or more functional isocyanate compound are used in combination as an isocyanate-based crosslinking agent, the compounding ratio (mass ratio) of both compounds is [difunctional isocyanate [Compound]/[trifunctional or more functional isocyanate compound] (mass ratio) is preferably 0.1/99.9 to 50/50, more preferably 0.1/99.9 to 20/80, 0.1/99.9 to 10/90 is more preferable, 0.1/99.9 to 5/95 is more preferable, and 0.1/99.9 to 1/99 is most preferable. By blending in this way, it becomes a pressure-sensitive adhesive layer excellent in tackiness and repulsion resistance, which is a preferable embodiment.

Examples of the epoxy compound include N,N,N′,N′-tetraglycidyl-m-xylenediamine (trade name TETRAD-X, manufactured by Mitsubishi Gas Chemical Co., Inc.) and 1,3-bis(N,N-di). Glycidylaminomethyl)cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Co., Inc.) and the like.

Examples of the melamine-based resin include hexamethylolmelamine. Examples of the aziridine derivative include trade names HDU, TAZM, and TAZO (these are manufactured by Mutual Pharmaceutical Co., Ltd.).

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

The content of the crosslinking agent used in the present invention is, for example, preferably 0.01 to 10 parts by mass, and 0.1 to 8 parts by mass with respect to 100 parts by mass of the (meth)acrylic polymer. The content is more preferably contained, further preferably 0.5 to 7 parts by mass, further preferably 1.0 to 5 parts by mass. When the content is less than 0.01 parts by mass, the formation of crosslinks by the crosslinker becomes insufficient, the cohesive force of the obtained pressure-sensitive adhesive layer becomes small, and sufficient heat resistance may not be obtained in some cases. It tends to cause glue residue. On the other hand, when the content exceeds 10 parts by mass, the cohesive force of the polymer is large, the fluidity is lowered, and the adherend (for example, a polarizing plate) is insufficiently wetted, so that the adherend and the adhesive are It tends to cause blisters generated 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 crosslinking catalyst for more effectively promoting the above-mentioned crosslinking reaction. Examples of such a crosslinking catalyst include tin-based catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris(acetylacetonato)iron, tris(hexane-2,4-dionate)iron, tris(heptane-2,4-dionat). Iron, tris(heptane-3,5-dionato)iron, tris(5-methylhexane-2,4-dionato)iron, tris(octane-2,4-dionato)iron, tris(6-methylheptane-2, 4-Dionato)iron, tris(2,6-dimethylheptane-3,5-dionat)iron, tris(nonane-2,4-dionat)iron, tris(nonane-4,6-dionato)iron, tris(2 ,2,6,6-Tetramethylheptane-3,5-dionato)iron, tris(tridecane-6,8-dionato)iron, tris(1-phenylbutane-1,3-dionato)iron, tris(hexafluoro) Acetylacetonato) iron, tris(acetoacetate ethyl)iron, tris(acetoacetate-n-propyl)iron, tris(isopropylacetoacetate)iron, tris(acetoacetate-n-butyl)iron, tris(acetoacetate-sec) -Butyl) iron, tris(acetoacetic acid-tert-butyl) iron, tris(propionyl methyl acetate) iron, tris(propionyl ethyl acetate) iron, tris(propionyl acetic acid-n-propyl) iron, tris(propionyl isopropyl acetate) iron , Tris(propionyl acetate-n-butyl) iron, tris(propionyl acetate-sec-butyl) iron, tris(propionyl acetate-tert-butyl) iron, tris(benzyl acetoacetate) iron, tris(dimethyl malonate) iron, Iron-based catalysts such as tris(diethyl malonate) iron, trimethoxy iron, triethoxy iron, triisopropoxy iron, ferric chloride can be used. These crosslinking catalysts may be used alone or in combination of two or more.

The content (use amount) of the crosslinking catalyst is not particularly limited, but is preferably about 0.0001 to 1 part by mass with respect to 100 parts by mass of the (meth)acrylic polymer, and 0.001 ˜0.5 parts by mass is more preferred. Within the above range, the crosslinking reaction rate is high when the pressure-sensitive adhesive layer is formed, and the pot life of the pressure-sensitive adhesive composition becomes long, which is a preferred embodiment.

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

The pressure-sensitive adhesive sheet of the present invention is formed by forming the pressure-sensitive adhesive layer on the second resin layer. At this time, the crosslinking of the pressure-sensitive adhesive composition is generally performed after coating the pressure-sensitive adhesive composition. However, it is also possible to transfer the pressure-sensitive adhesive layer made of the pressure-sensitive adhesive composition after crosslinking to a resin layer or the like.

The method for forming the pressure-sensitive adhesive layer on the second resin layer is not particularly limited. For example, the pressure-sensitive adhesive layer may be formed by applying the pressure-sensitive adhesive composition (solution) to the resin layer and drying and removing the polymerization solvent. Is formed on the resin layer. Thereafter, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction. When the pressure-sensitive adhesive composition is applied onto the resin layer to prepare a pressure-sensitive adhesive sheet, one or more solvents other than the polymerization solvent are newly added to the pressure-sensitive adhesive composition so that the pressure-sensitive adhesive composition can be uniformly applied onto the resin layer. May be added to.

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 roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and extrusion coating using a die coater.

Usually, the thickness of the pressure-sensitive adhesive layer is 3 to 100 μm, and 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 a suitable balance between removability and adhesiveness (adhesion), which is preferable.

<Separator>
In the pressure-sensitive adhesive sheet of the present invention, a 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.

As a material for forming the separator, there are paper and a plastic film, and the plastic film is preferably used because of its excellent surface smoothness. The film is not particularly limited as long as it is a film capable of protecting the pressure-sensitive adhesive layer, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer Examples thereof include a united 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 5 to 200 μm, preferably 10 to 100 μm. It is preferable for it to be in the above-mentioned range since the workability of attaching to the pressure-sensitive adhesive layer and the workability of peeling from the pressure-sensitive adhesive layer are excellent. In the separator, if necessary, a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, release and antifouling treatment with silica powder or the like, coating type, kneading type, vapor deposition type It is also possible to perform antistatic treatment such as.

<Top coat layer (antistatic layer)>
The pressure-sensitive adhesive sheet of the present invention has a topcoat layer on the surface opposite to the surface having the pressure-sensitive adhesive layer of the first resin layer, and the topcoat layer is a polyanilinesulfonic acid as a conductive polymer component, It is preferably formed from a composition for a topcoat layer containing a polyester resin as a binder component and an isocyanate compound as a crosslinking agent. When the pressure-sensitive adhesive sheet has the top coat layer, the antistatic property of the pressure-sensitive adhesive sheet is improved, which is a preferred embodiment.

<Conductive polymer>
In a preferred embodiment, the top coat layer contains polyanilinesulfonic acid as a conductive polymer component. By using the conductive polymer, the antistatic property based on the topcoat layer and the antistatic property over time can be satisfied. Although the polyanilinesulfonic acid is “water-soluble”, it can be fixed in the top coat layer and the water resistance can be improved by using the isocyanate crosslinking agent described later. By using the water-soluble conductive polymer-containing aqueous solution, a top coat layer having an excellent surface resistivity over time can be obtained, which is a preferred embodiment. On the other hand, when the conductive polymer used in forming the topcoat layer is "water dispersible", when the topcoat layer is formed using the water-dispersible conductive polymer-containing solution, aggregates are generated. It is not preferable because it becomes easy, the coating cannot be applied uniformly, and the surface resistivity over time tends to be significantly inferior.

The amount of the conductive polymer used is preferably 10 to 200 parts by mass, more preferably 25 to 150 parts by mass, and still more preferably 40 to 120 parts by mass with respect to 100 parts by mass of the binder contained in the top coat layer. It is a mass part. If the amount of the conductive polymer used is too small, the antistatic effect may be reduced, and if the amount of the conductive polymer used is too large, the adhesion to the resin layer of the topcoat layer may decrease, or the transparency may be low. It is not preferable because it may decrease.

The polyanilinesulfonic acid used as the conductive polymer component preferably has a polystyrene-equivalent weight average molecular weight (Mw) of 5×10 ⁵ or less, more preferably 3×10 ⁵ or less. The weight average molecular weight of these conductive polymers is usually preferably 1×10 ³ or more, more preferably 5×10 ³ or more.

As a method of forming the top coat layer, a method of applying and drying (or curing) the composition for the top coat layer (coating material for forming the top coat layer) on the first surface of the resin layer (base material/support). As the conductive polymer component that can be adopted and used for preparing the composition for the top coat layer, polyaniline sulfonic acid, a polyester resin as a binder, and an isocyanate-based crosslinking agent as a crosslinking agent are contained as components. A form dissolved in water (a conductive polymer aqueous solution or simply an aqueous solution) can be preferably used. The conductive polymer aqueous solution is prepared, for example, by dissolving a conductive polymer having a hydrophilic functional group (which can be synthesized by a method such as copolymerizing a monomer having a hydrophilic functional group in the molecule) in water. can do. Examples of the hydrophilic functional group include a sulfo group, an amino group, an amide group, an imino group, a hydroxyl group, a mercapto group, a hydrazino group, a carboxyl group, a quaternary ammonium group, a sulfate ester group (—O—SO ₃ H), and a phosphorus group. An acid ester group (for example, -O-PO(OH) ₂ ) and the like are exemplified. Such hydrophilic functional group may form a salt.

Moreover, as a commercial item of the said polyaniline sulfonic acid aqueous solution, the brand name by the Mitsubishi Rayon Co., Ltd. "aqua-PASS" etc. are illustrated.

The topcoat layer disclosed herein contains polyaniline sulfonic acid (polyaniline type) as the conductive polymer component, and for example, one or more other antistatic components (organic compounds other than the conductive polymer are used. Conductive material, inorganic conductive material, antistatic agent, etc.) may be included together. In a preferred embodiment, the top coat layer does not substantially contain an antistatic component other than the conductive polymer, that is, the antistatic component contained in the top coat layer is substantially a conductive polymer. Can be more preferably carried out.

Examples of the organic conductive substance include a cation type antistatic agent having a cationic functional group such as a quaternary ammonium salt, a pyridinium salt, a primary amino group, a secondary amino group and a tertiary amino group; a sulfonate or a sulfate ester. Anionic antistatic agents having anionic functional groups such as salts, phosphonates and phosphate salts; zwitterionic antistatic agents such as alkylbetaine and its derivatives, imidazoline and its derivatives, alanine and its derivatives; amino alcohols And its derivatives, glycerin and its derivatives, polyethylene glycol and its derivatives, and other nonionic antistatic agents; the above-mentioned cationic, anionic, and zwitterionic ion-conductive groups (for example, quaternary ammonium salt group)-containing monomers are polymerized. Alternatively, an ion conductive polymer obtained by copolymerization; a conductive polymer such as polythiophene, polyaniline, polypyrrole, polyethyleneimine, and an allylamine-based polymer; Such antistatic agents may be used alone or in combination of two or more.

As the inorganic conductive material, tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, indium, tin, antimony, gold, silver, copper, aluminum, nickel, chromium, titanium, iron, cobalt, Examples include copper iodide, ITO (indium oxide/tin oxide), ATO (antimony oxide/tin oxide), and the like. Such inorganic conductive materials may be used alone or in combination of two or more.

As the antistatic agent, a cationic type antistatic agent, an anion type antistatic agent, a zwitterionic type antistatic agent, a nonionic type antistatic agent, a single type having anionic conductive group of the cationic type, anionic type and zwitterionic type. Examples thereof include an ion conductive polymer obtained by polymerizing or copolymerizing a monomer.

<Binder>
It is a preferred embodiment that the top coat layer contains a polyester resin as a binder. The polyester resin is preferably a resin material containing polyester as a main component (typically more than 50% by mass, preferably 75% by mass or more, for example, 90% by mass or more). The polyester typically includes polyvalent carboxylic acids having two or more carboxyl groups in one molecule (typically dicarboxylic acids) and derivatives thereof (anhydrides, esterified products, halogens of the polyvalent carboxylic acids). Selected from polyhydric alcohols (typically diols) having at least two hydroxyl groups in one molecule. It is preferable to have a structure in which the above-mentioned one or more compounds (polyhydric alcohol component) are condensed.

Examples of compounds that can be used as the polycarboxylic acid component include oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±)-malic acid, and meso. -Tartaric acid, itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, adipic acid, dithioadipic acid, methyladipic acid, dimethyl Adipic acid, tetramethyladipic acid, methyleneadipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,3,6,6-tetramethylsuberic acid, azelaic acid, sebacic acid, perfluoro Aliphatic dicarboxylic acids such as sebacic acid, brassic acid, dodecyldicarboxylic acid, tridecyldicarboxylic acid, tetradecyldicarboxylic acid; cycloalkyldicarboxylic acid (for example, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid), Alicyclic dicarboxylic acids such as 1,4-(2-norbornene)dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid (hymic acid), adamantanedicarboxylic acid, spiroheptanedicarboxylic acid; phthalic acid, isophthalic acid, dithio Isophthalic acid, methylisophthalic acid, dimethylisophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methylterephthalic acid, dimethylterephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalenedicarboxylic acid, oxofluorangecarboxylic acid, anthracenedicarboxylic acid , Biphenyldicarboxylic acid, biphenylenedicarboxylic acid, dimethylbiphenylenedicarboxylic acid, 4,4"-p-terephenylenedicarboxylic acid, 4,4"-p-quarrelphenyldicarboxylic acid, bibenzyldicarboxylic acid, azobenzenedicarboxylic acid, homophthalic acid , Phenylenediacetic acid, phenylenedipropionic acid, naphthalenedicarboxylic acid, naphthalenedipropionic acid, biphenyldiacetic acid, biphenyldipropionic acid, 3,3'-[4,4'-(methylenedi-p-biphenylene)dipropionic acid, Aromatic dicarboxylic acids such as 4,4′-bibenzyldiacetic acid, 3,3′(4,4′-bibenzyl)dipropionic acid, and oxydi-p-phenylenediacetic acid; acids of any of the above polyvalent carboxylic acids Anhydride; S of any of the above-mentioned polycarboxylic acids Tell (eg alkyl ester. It can be a monoester, a diester and the like. ); an acid halide (for example, dicarboxylic acid chloride) corresponding to any of the above-described polycarboxylic acids; and the like.

Suitable examples of compounds that can be adopted as the polyvalent carboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid and naphthalene dicarboxylic acid and acid anhydrides thereof; adipic acid, sebacic acid, azelaic acid, succinic acid, Aliphatic dicarboxylic acids such as fumaric acid, maleic acid, hymic acid, 1,4-cyclohexanedicarboxylic acid and their acid anhydrides; and lower alkyl esters of the dicarboxylic acids (for example, with monoalcohols having 1 to 3 carbon atoms) Ester) and the like.

On the other hand, examples of compounds that can be adopted as the polyhydric alcohol component include ethylene glycol, propylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, and 1,4-butanediol. , Neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, 3-methylpentanediol, diethylene glycol, 1,4-cyclohexanedimethanol, 3-methyl-1,5-pentanediol, 2-methyl- Diols such as 1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, xylylene glycol, hydrogenated bisphenol A and bisphenol A Is mentioned. Other examples include alkylene oxide adducts of these compounds (eg, ethylene oxide adducts, propylene oxide adducts, etc.).

The molecular weight of the polyester resin is, for example, about 5×10 ^{3 to} 1.5×10 ⁵ (preferably 1×10 5) as a weight average molecular weight (Mw) in terms of standard polystyrene measured by gel permeation chromatography (GPC). ^{4 to} 6×10 ⁴ )). The glass transition temperature (Tg) of the polyester resin may be, for example, 0 to 120°C (preferably 10 to 80°C).

As the polyester resin, commercially available Toyobo Co., Ltd. trade name “Bironard” and the like can be used.

The topcoat layer is a binder other than polyester resin (for example, acrylic resin, acrylic-urethane resin) as long as the performance (for example, performance such as antistatic property) of the pressure-sensitive adhesive sheet disclosed herein is not significantly impaired. , Acrylic-styrene resin, acrylic-silicone resin, silicone resin, polysilazane resin, polyurethane resin, fluororesin, polyolefin resin and the like). In a preferred embodiment of the technique disclosed herein, the binder of the topcoat layer is substantially made of polyester resin. For example, a topcoat layer in which the proportion of the polyester resin in the binder is 98 to 100% by mass is preferable. The proportion of the binder in the entire top coat layer can be, for example, 50 to 95% by mass, and usually 60 to 90% by mass is suitable.

<Lubricant>
The top coat layer in the technique disclosed herein is preferably a mode in which a fatty acid amide is used as a lubricant. By using a fatty acid amide as a lubricant, a further release treatment (for example, a treatment of applying a known release treatment such as a silicone release agent or a long-chain alkyl release agent and drying it) on the surface of the top coat layer is performed. Even in the case where it is not applied, it is possible to obtain a top coat layer having both sufficient slipperiness and print adhesion, which may be a preferable mode. As described above, the embodiment in which the surface of the top coat layer is not further subjected to the peeling treatment can prevent the whitening (for example, the whitening due to the storage under the heating and humidifying conditions) caused by the peeling treatment agent. It is preferable in terms. It is also advantageous in terms of solvent resistance.

Specific examples of the fatty acid amide include lauric acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, hydroxystearic acid amide, oleic acid amide, erucic acid amide, N-oleylpaltimic acid amide, and N-stearyl stearic acid. Amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid amide, methylenebisstearic acid amide, ethylenebiscapric acid amide, ethylenebislauric acid amide, ethylenebisstearic acid Amide, ethylene bishydroxystearic acid amide, ethylene bisbehenic acid amide, hexamethylene bisbehenic acid amide, hexamethylene bisbehenic acid amide, hexamethylene hydroxystearic acid amide, N,N'-distearyl adipic acid amide, N,N ′-Distearyl sebacic acid amide, ethylenebisoleic acid amide, ethylenebiserucic acid amide, hexamethylenebisoleic acid amide, N,N′-dioleyl adipamic acid amide, N,N′-dioleyl sebacic acid amide, m -Xylylenebisstearic acid amide, m-xylylenebishydroxystearic acid amide, N,N'-stearylisophthalic acid amide and the like can be mentioned. These lubricants may be used alone or in combination of two or more.

The proportion of the lubricant in the entire top coat layer can be 1 to 50% by mass, and usually 5 to 40% by mass is suitable. If the content ratio of the lubricant is too small, the slipperiness tends to decrease. If the content of the lubricant is too large, the print adhesion may be reduced.

The technique disclosed herein can be carried out in a mode in which the topcoat layer contains other lubricant in addition to the fatty acid amide, as long as the application effect is not significantly impaired. Examples of such other lubricants include various waxes such as petroleum wax (paraffin wax and the like), mineral wax (montan wax and the like), higher fatty acid (cerotic acid and the like), and neutral fat (palmitic acid triglyceride and the like). Be done. Alternatively, in addition to the wax, a general silicone lubricant, a fluorine lubricant or the like may be supplementarily contained. The technique disclosed herein can be preferably carried out in a mode in which the silicone-based lubricant, the fluorine-based lubricant and the like are not substantially contained. However, as long as the application effect of the technology disclosed herein is not significantly impaired, the addition of a silicone compound used for a purpose other than the lubricant (for example, as an antifoaming agent for the composition for the top coat layer described later) is not included. It does not exclude.

<Crosslinking agent>
In a preferred embodiment, the top coat layer contains an isocyanate cross-linking agent as a cross-linking agent. By using the isocyanate-based cross-linking agent, water-soluble polyaniline sulfonic acid can be fixed in the binder when forming the top coat layer, and excellent water resistance is achieved, and further, effects such as improvement of print adhesion are realized. be able to.

Further, it is a preferred embodiment that a blocked isocyanate-based crosslinking agent that is stable in an aqueous solution is used as the isocyanate-based crosslinking agent. Specific examples of the blocked isocyanate-based cross-linking agent include an isocyanate-based cross-linking agent that can be used in the preparation of a general pressure-sensitive adhesive layer or a top coat layer (for example, an isocyanate compound (isocyanate used in the pressure-sensitive adhesive layer described below. Crosslinkers)) are alcohols, phenols, thiophenols, amines, imides, oximes, lactams, active methylene compounds, mercaptans, imines, ureas, diaryl compounds, and bisulfite. You can use the one blocked with soda.

The topcoat layer in the technology disclosed herein may include an antioxidant, a colorant (pigment, dye, etc.), a fluidity modifier (thixotropic agent, thickener, etc.), a film-forming aid, an interface, if necessary. It may contain additives such as an activator (antifoaming agent), a preservative, an ultraviolet absorber, a dispersant, an antiblocking agent and the like.

<Formation of top coat layer>
The topcoat layer is a liquid composition (composition for topcoat layer) in which a component such as the conductive polymer component and additives used as necessary are dissolved in a suitable solvent (such as water) is used as a resin layer. It can be suitably formed by a method including applying. For example, a method of applying the composition for a top coat layer to the first surface of the resin layer, drying the composition, and optionally performing a curing treatment (heat treatment, ultraviolet treatment, etc.) can be preferably adopted. The NV (nonvolatile content) of the composition for the topcoat layer can be, for example, 5% by mass or less (typically 0.05 to 5% by mass), and usually 1% by mass or less (typically 0.10 to 1 mass%) is suitable. When forming a topcoat layer having a small thickness, the NV of the composition for a topcoat layer is preferably, for example, 0.05 to 0.50 mass% (for example, 0.10 to 0.40 mass%). .. By using the low NV composition for the top coat layer, a more uniform top coat layer can be formed.

As the solvent constituting the composition for the topcoat layer (coating material for forming the topcoat layer), those capable of stably dissolving the components forming the topcoat layer are preferable. The solvent may be an organic solvent, water, or a mixed solvent thereof. Examples of the organic solvent include esters such as ethyl acetate; ketones such as methyl ethyl ketone, acetone and cyclohexanone; cyclic ethers such as tetrahydrofuran (THF) and dioxane; aliphatic or alicyclic compounds such as n-hexane and cyclohexane. Hydrocarbons; aromatic hydrocarbons such as toluene and xylene; aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol, cyclohexanol; alkylene glycol monoalkyl ethers (for example, ethylene glycol monomethyl ether) , Ethylene glycol monoethyl ether), dialkylene glycol monoalkyl ether, and other glycol ethers; and the like. In a preferred aspect, the solvent of the composition for a topcoat layer is water or a mixed solvent containing water as a main component (for example, a mixed solvent of water and ethanol).

<Properties of top coat layer>
The thickness of the topcoat layer in the technology disclosed herein is typically 3 to 500 nm, preferably 10 to 100 nm, more preferably 20 to 60 nm). If the thickness of the topcoat layer is too small, it will be difficult to form the topcoat layer uniformly (for example, in the thickness of the topcoat layer, there will be a large variation in thickness depending on the location). Unevenness may occur easily. On the other hand, if it is too thick, the characteristics of the resin layer (optical characteristics, dimensional stability, etc.) may be affected.

In a preferred embodiment of the pressure-sensitive adhesive sheet disclosed herein, the surface resistivity (Ω/□) measured on the surface of the top coat layer is preferably less than 1.0×10 ¹¹ and more preferably It is less than 5.0×10 ¹⁰ and more preferably less than 1.5×10 ¹⁰ . The pressure-sensitive adhesive sheet having a surface resistivity within the above range can be suitably used as a pressure-sensitive adhesive sheet used, for example, in the processing or transportation of articles such as liquid crystal cells and semiconductor devices that are sensitive to static electricity. The surface resistivity can be calculated from the surface resistivity measured in an atmosphere of 23° C. and 50% RH using a commercially available insulation resistance measuring device.

The pressure-sensitive adhesive sheet disclosed herein preferably has a property that the back surface (the surface of the top coat layer) can be easily printed with a water-based ink or an oil-based ink (for example, using an oil-based marking pen). Such a pressure-sensitive adhesive sheet describes the identification number of the adherend to be protected in the pressure-sensitive adhesive sheet in the process of processing or conveying the adherend (for example, an optical component) performed with the pressure-sensitive adhesive sheet attached. Suitable for display. Therefore, it is preferable that the pressure-sensitive adhesive sheet has excellent printability. For example, it is preferable that the solvent is alcoholic and has high printability with respect to an oil-based ink of a type including a pigment. Further, it is preferable that the printed ink is difficult to be removed due to rubbing or transfer (that is, the printing adhesion is excellent). The pressure-sensitive adhesive sheet disclosed herein also preferably has solvent resistance to the extent that when the print is corrected or erased, the print is wiped off with alcohol (for example, ethyl alcohol) without causing a noticeable change in appearance. ..

The pressure-sensitive adhesive sheet disclosed herein can also be embodied in a mode including another layer in addition to the resin layer, the adhesive layer, the pressure-sensitive adhesive layer, and the top coat layer. The "other layer" may be arranged between the first surface (back surface) of the first resin layer and the top coat layer, and between the second surface (front surface) of the second resin layer and the adhesive layer. Etc. are illustrated. The layer arranged between the back surface of the first resin layer and the top coat layer can be, for example, a layer containing an antistatic component (the above-mentioned top coat layer). The layer arranged between the front surface of the second resin layer and the pressure-sensitive adhesive layer may be, for example, an undercoat layer (anchor layer) or a topcoat layer that enhances the anchoring property of the pressure-sensitive adhesive layer to the second surface. .. The pressure-sensitive adhesive sheet may have a configuration in which the topcoat layer is disposed on the front surface of the second resin layer, the anchor layer is disposed on the topcoat layer, and the pressure-sensitive adhesive layer is disposed thereon.

The optical member of the present invention is preferably protected by the pressure-sensitive adhesive sheet. Since the pressure-sensitive adhesive sheet has excellent pick-up properties, it can be used for surface protection applications (pressure-sensitive adhesive sheet) during processing, transportation, shipping, etc., and is useful for protecting the surface of the optical member (polarizing plate, etc.). Becomes In particular, when it has a top coat layer or when an antistatic component is blended in the pressure-sensitive adhesive layer, it can be used for plastic products that easily generate static electricity, so that electrification is a serious problem. In the related technical field, it will be very useful for antistatic applications.

The total thickness of the pressure-sensitive adhesive sheet of the present invention is preferably 14 to 400 μm, more preferably 40 to 200 μm, and most preferably 55 to 100 μm. Within the above range, the adhesive properties (removability, adhesiveness, etc.), workability, etc. are excellent, and this is a preferred embodiment. The total thickness means the total thickness including all layers such as the resin layer, the adhesive layer, the pressure-sensitive adhesive layer, and the top coat layer.

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

Moreover, 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) was measured using a GPC device (HLC-8220GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.

Sample concentration: 0.2 mass% (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow rate: 0.6 ml/min
Measurement temperature: 40°C
column:
Sample column; TSKguard super column HZ-H (1 line) + TSK gel Super HZM-H (2 lines)
Reference column; TSKgel Super H-RC (1)
Detector: Differential refractometer (RI)
The weight average molecular weight was calculated in terms of polystyrene. Also, when it was necessary to measure the number average molecular weight (Mn), the measurement was performed in the same manner as the weight average molecular weight.

<Glass transition temperature (Tg)>
The glass transition temperature Tg (° C.) was determined by the following formula using the following literature values as the glass transition temperature Tgn (° C.) of the homopolymer of each monomer.

Formula: 1/(Tg+273)=Σ[Wn/(Tgn+273)]
[Wherein Tg (°C) is the glass transition temperature of the copolymer, Wn (-) is the weight fraction of each monomer, Tgn (°C) is the glass transition temperature of the homopolymer of each monomer, and n is the type of each monomer] Represents. ]
Literature value:
2-Ethylhexyl acrylate (2EHA): -70°C
n-Butyl acrylate (BA): -55°C
2-Hydroxyethyl acrylate (HEA): -15°C
Acrylic acid (AA): 106°C

As literature values, "Synthesis and design of acrylic resin and development of new applications" (published by the Central Management Development Center), "Polymer Handbook" (John Wiley & Sons), and Kadalog value of monomer manufacturer were referenced.

The glass transition temperature (Tg) (°C) of the (meth)acrylic polymer obtained from a monomer whose literature value is unknown was determined by dynamic viscoelasticity measurement according to the following procedure.
First, a sheet of (meth)acrylic polymer having a thickness of 20 μm is laminated to have a thickness of about 2 mm, and this is punched into φ7.9 mm to prepare a cylindrical pellet, which is used as a sample for measuring glass transition temperature (Tg). did.
Using the above-mentioned measurement sample, the measurement sample was fixed to a jig of φ7.9 mm parallel plate, and the temperature dependence of the loss elastic modulus G″ was measured by a dynamic viscoelasticity measuring device (ARES, manufactured by Rheometrics). The glass transition temperature (Tg) (° C.) was determined as the temperature at which the G″ curve obtained by the measurement was maximized. The measurement conditions are as follows.
Measurement: Shear mode Temperature range: -70°C to 150°C
Temperature range: 5℃/min
Frequency: 1 Hz

<Thickness measurement>
The measurement was performed using a digital micrometer (manufactured by Anritsu Corporation, product name "KC-351C").

<Tensile strength>
It was measured using a tensile tester (manufactured by Shimadzu Corporation, product name “Autograph”) according to JIS C 2318.

<Storage elastic modulus of adhesive layer>
An adhesive layer was laminated to have a thickness of about 2 mm, which was punched out to a diameter of 7.9 mm to produce a cylindrical pellet, which was used as a measurement sample. Using the above measurement sample, the above measurement sample was fixed to a jig of φ7.9 mm parallel plate, and the storage elastic modulus G′ at 23° C. was measured by a dynamic viscoelasticity measuring device (ARES, manufactured by Rheometrics). did. The measurement conditions are as follows.
Measurement: Shear mode Frequency: 1Hz
The storage elastic modulus (23° C.) of the adhesive layer in the present invention is 1.0×10 ⁴ Pa or more and less than 5.0×10 ⁷ Pa, and preferably 1.0×10 ⁴ Pa or more and 1.0×. It is less than 10 ⁷ Pa, more preferably 1.0×10 ⁵ Pa or more and less than 1.0×10 ⁶ Pa. Within the above range, the pressure-sensitive adhesive sheet has good pick-up properties, which is a preferable mode.

<Measurement of surface resistivity>
In an atmosphere of a temperature of 23° C. and a humidity of 50% RH, a resistivity meter (HIRESTA UP MCP-HT450 type manufactured by Mitsubishi Chemical Analytical Co., Ltd.) was used for measurement according to JIS-K-6911.
The surface resistivity (Ω/□) in the present invention is preferably 1.0× both at the initial stage and at room temperature (RT) (23° C.×50% RH)×1 week (7 days). It is less than 10 ¹¹ , more preferably less than 5.0×10 ¹⁰ and even more preferably less than 1.5×10 ¹⁰ . The pressure-sensitive adhesive sheet having a surface resistivity within the above range can be suitably used as a pressure-sensitive adhesive sheet used, for example, in the processing or transportation of articles such as liquid crystal cells and semiconductor devices that are sensitive to static electricity.

<Measurement of peeling electrification voltage (polarizing plate side)>
After 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 and the release liner was peeled off, as shown in FIG. 2, an acrylic plate 3 (manufactured by Mitsubishi Rayon Co., Ltd. Adhesion to the surface of polarizing plate 2 (SEG1423DU polarizing plate manufactured by Nitto Denko Corp., width: 70 mm, length: 100 mm) attached to the name "Acrylite", thickness: 1 mm, width: 70 mm, length: 100 mm) The sheet 1 was pressed by a hand roller so that one end thereof protruded from the edge of the polarizing plate 2 by 30 mm.
This sample was left in an environment of 23° C.×50% RH for 1 day and then set at a predetermined position on a sample fixing base 4 having a height of 20 mm. The end of the pressure-sensitive adhesive sheet 1 protruding 30 mm from the polarizing plate 2 was fixed to an automatic winder (not shown) and peeled off at a peeling angle of 150° and a peeling speed of 10 m/min. A potential measuring device 5 (Kasuga Denki Co., Ltd., model “KSD-0103”) in which the potential of the surface of the adherend (polarizing plate) generated at this time is fixed at a position 100 mm in height from the center of the polarizing plate 2. The "initial polarizing plate peeling electrification voltage" was measured. The measurement was performed in an environment of 23° C. and 50% RH.
The peeling electrification voltage (kV) (absolute value) in the present invention is preferably 1 or less, more preferably 0.9 or less, and further preferably 0.5 or less. Within the above range, for example, damage to the liquid crystal driver or the like can be prevented, which is a preferable mode.

<Back Adhesion (A) measurement>
As shown in FIG. 3, the pressure-sensitive adhesive sheet 1 according to each example is cut into a size having a width of 70 mm and a length of 100 mm, and the pressure-sensitive adhesive surface (the side provided with the pressure-sensitive adhesive layer 20) 20A of this pressure-sensitive adhesive sheet 1 is double-sided adhesive. It was fixed on the SUS304 stainless steel plate 132 using the tape 130. Single-sided adhesive tape having acrylic adhesive 162 on resin layer film (first resin layer, adhesive layer, second resin layer in this order) 164 (Nitto Denko Corporation, trade name "No. 31B", width 19 mm ) 160 was cut to a length of 100 mm. The adhesive surface 162A of the adhesive tape 160 was pressure-bonded to the back surface (that is, the surface of the top coat layer 14) 1A of the adhesive sheet 1 at a pressure of 0.25 MPa and a speed of 0.3 m/min. This was left for 30 minutes under the conditions of 23° C. and 50% RH. Then, using a universal tensile tester, the adhesive tape 160 was peeled from the back surface 1A of the adhesive sheet 1 under the conditions of a peeling speed of 0.3 m/min and a peeling angle of 180 degrees. At this time, the adhesive force (A) [N /19 mm] was measured.

The back adhesive force (A) is preferably 3.0 N/19 mm or more, more preferably 4.0 N/19 mm or more, further preferably 5.0 N/19 mm or more, and most preferably 6 It is 0.0 N/19 mm or more. If the adhesive force is less than 3.0 N/19 mm, sufficient adhesive force cannot be obtained, the pick-up property is deteriorated, and the peeling workability of the protective film is deteriorated, which is not preferable.

<Adhesion force (B) measurement against polarizing plate>
As an adherend, a plain polarizing plate having a width of 70 mm and a length of 100 mm (TAC polarizing plate manufactured by Nitto Denko Corporation, SEG1425DU) was prepared. The pressure-sensitive adhesive sheet according to each example was cut into a size having a width of 25 mm and a length of 100 mm, and the pressure-sensitive adhesive surface thereof was pressure-bonded to the polarizing plate at a pressure of 0.25 MPa and a speed of 0.3 m/min. After leaving this for 30 minutes in an environment of 23° C. and 50% RH, an adhesive sheet was attached from the above polarizing plate under the same environment using a universal tensile tester under the conditions of a peeling speed of 0.3 m/min and a peeling angle of 180°. Was peeled off, and the adhesive force (B) [N/25 mm] at this time was measured.
The adhesive force (B) is preferably 3.0 N/25 mm or less, more preferably 2.5 N/25 mm or less, further preferably 2.0 N/25 mm or less, and particularly preferably 1 It is 0.6 N/25 mm or less, and most preferably 1.0 N/25 mm or less. If the adhesive strength is more than 3.5 N/25 mm, the peeling workability becomes poor, which is not preferable.

<Adhesiveness after peeling off the protective film (adhesive sheet)>
The pressure-sensitive adhesive sheet according to each example was pressure-bonded to a plain polarizing plate (TAC polarizing plate manufactured by Nitto Denko Corporation, SEG1425DU) at a pressure of 0.25 MPa and a speed of 0.3 m/min. Then, after leaving it at room temperature for 1 day, the pressure-sensitive adhesive sheet was peeled off. Subsequently, an adhesive surface of an acrylic tape having a length of 70 mm and a width of 19 mm (manufactured by Nitto Denko Corporation, product number No. 31B) having a length of 70 mm and a width of 19 mm was attached at a temperature of 23° C. and a humidity of 50% on the surface of the polarizing plate to which the adhesive sheet was attached. Adhesion, pressure bonding at 0.25 MPa, 300 mm/min, and leaving for 30 minutes at a temperature of 23° C. and a humidity of 50%, then using a tensile tester, 180° peel adhesion (temperature 23° C., humidity 50% RH, peeling angle 180[deg.], pulling speed 300 mm/min) [N/19 mm] was measured, and the adhesiveness after peeling the protective film (adhesive sheet) was evaluated from the adhesive strength at this time.
The adhesive force after peeling off the protective film (adhesive sheet) is preferably 3 N/19 mm or more, more preferably 5 N/19 mm or more, further preferably 6.3 N/19 mm or more, and particularly preferably , 6.7 N/19 mm or more, and most preferably 6.9 N/19 mm or more. If the adhesive force is less than 3 N/19 mm, sufficient adhesive force cannot be obtained, the pick-up property is deteriorated, and the peeling workability of the protective film is deteriorated, which is not preferable.

<Pickup>
As shown in FIG. 4, the pressure-sensitive adhesive sheet 1 according to each example is cut into a size having a width of 50 mm and a length of 100 mm, and the pressure-sensitive adhesive surface (the side provided with the pressure-sensitive adhesive layer 20) 20A of the pressure-sensitive adhesive sheet 1 is changed to a plane-polarized light. A plate (TAC polarizing plate manufactured by Nitto Denko Corporation, SEG1425DU) 50 was pressure-bonded at a pressure of 0.25 MPa and a speed of 0.3 m/min.
A one-sided adhesive tape 60 (manufactured by Nitto Denko Corporation, trade name "No. 31B") was cut into a width of 10 mm and a length of 50 mm. The adhesive layer (adhesive surface) 62 of the adhesive tape 60 was manually pressure-bonded to the center of the back surface (that is, the surface of the top coat layer 14) having a width of 50 mm of the adhesive sheet 1 so that the end portion protrudes 30 mm. This was left for 10 seconds under the conditions of 23° C. and 50% RH. Then, the one-sided adhesive tape 60 was peeled by hand, and the peeling condition (pickup property) of the adhesive sheet 1 was evaluated.
The evaluation criteria were ◯ when the pressure-sensitive adhesive sheet was peelable, and x when the pressure-sensitive adhesive sheet remained without being peeled off.

<Amount of deflection>
As shown in FIG. 5, the pressure-sensitive adhesive sheet 1 according to each example was cut into a size having a width of 20 mm and a length of 150 mm, and the end portion was made to have a No. No. manufactured by Nitto Denko Corporation so that the pressure-sensitive adhesive surface of the pressure-sensitive adhesive sheet 1 faces outward. It was fixed to the glass plate G with 31B tape T. The height H1 of the center position of the adhesive sheet at that time was measured. Next, a load L of 4.8 g was placed at the center position, and the height H2 at the center position of the adhesive sheet at that time was measured. The amount of deflection [mm] was calculated by the following formula.
Deflection amount = H1-H2 [mm]
The amount of deflection is preferably 30 mm or less, more preferably 25 mm or less, and most preferably 20 mm or less. If the amount of deflection exceeds 30 mm, the optical member to which the pressure-sensitive adhesive sheet is attached tends to bend during the carrying process, which is not preferable.

The methods for preparing the topcoat layer, the pressure-sensitive adhesive composition (pressure-sensitive adhesive solution), and the pressure-sensitive adhesive sheet (surface protective film) are described below.

[Example 1]
<Preparation of resin layer film (first resin layer, adhesive layer, and second resin layer in this order)>
In a reaction vessel equipped with a cooling pipe, a nitrogen introducing pipe, a thermometer and a stirrer, 100 parts by mass of butyl acrylate (BA), 5.0 parts by mass of acrylic acid (AA), and 2-hydroxyethyl acrylate (2HEA). 0.075 parts by mass, 2,2′ azobisisonitrile 0.3 parts by mass, and ethyl acetate were added, and the mixture was reacted under a nitrogen gas stream at 60° C. for 6 hours with stirring to give a weight average molecular weight of 163,000. To obtain an acrylic polymer solution. With respect to 100 parts by mass of the polymer solid content of this acrylic polymer solution, 0.6 part by mass of an isocyanate-based polyfunctional compound (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name: Coronate L) and a silane coupling agent (Shin-Etsu Chemical Co., Ltd.) 0.08 parts by mass of the product (trade name: KBM403) manufactured by the same company was added to prepare an acrylic adhesive 1 composition solution.

As a resin layer, a polyester-based resin film (manufactured by Toyobo Co., Ltd., trade name: E5000, thickness: 38 μm, tensile strength: 208 MPa) was coated with the acrylic adhesive 1 composition solution and heated at 90° C. An adhesive layer having a thickness of 20 μm was formed. The storage elastic modulus at 23° C. of the obtained adhesive layer was 1.0×10 ⁵ Pa.
Then, a polyester resin film (manufactured by Toyobo Co., Ltd., trade name: E5000, thickness: 38 μm, tensile strength: 208 MPa) was laminated on the adhesive layer to obtain a resin layer film having a thickness of 96 μm.

<Preparation of acrylic adhesive 1 solution>
95 parts by mass of 2-ethylhexyl acrylate (2EHA), 5 parts by mass of 2-hydroxyethyl acrylate (HEA), and 2 as a polymerization initiator were placed in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser. , 2'-Azobisisobutyronitrile (0.2 parts by mass) and ethyl acetate (150 parts by mass) were charged, and nitrogen gas was introduced while gently stirring, and polymerization was performed for 6 hours while maintaining the liquid temperature in the flask at about 65°C. Reaction was carried out to prepare a (meth)acrylic polymer solution (40% by mass). The acrylic polymer had a weight average molecular weight of 550,000 and a glass transition temperature (Tg) of -68°C.

The acrylic polymer solution (40% by mass) was diluted to 20% by mass with ethyl acetate, and 500 parts by mass of this solution (100 parts by mass of solid content) was used as an alkylene oxide group-containing compound, 25R-1 (manufactured by ADEKA, product) 0.5 parts by mass (solid content 0.5 parts by mass), isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name: Coronate HX (C/ HX)) 4 parts by mass (solid content 4 parts by mass), dibutyltin dilaurate (1% by mass ethyl acetate solution) 2 parts by mass (solid content 0.02 parts by mass) as a cross-linking catalyst, and mixed and stirred to obtain an acrylic. A system adhesive 1 solution was prepared.

<Preparation of adhesive sheet (surface protection film)>
The acrylic pressure sensitive adhesive 1 solution is applied to the resin layer film (first resin layer, adhesive layer, second resin layer in this order) on the side opposite to the first resin layer, and at 130° C. for 1 minute. It heated and formed the 20-micrometer-thick adhesive layer. Then, a silicone-treated surface of a polyethylene terephthalate film (thickness: 25 μm), which is a separator whose one surface was treated with silicone, was attached to the surface of the pressure-sensitive adhesive layer to prepare a pressure-sensitive adhesive sheet (surface protective film).

[Example 13]
<Preparation of solution for top coat layer (top coat 1)>
As a binder, polyester resin Vironal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.), as a conductive polymer, polyaniline sulfonic acid (aqua-PASS, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.), and diisopropylamine as a cross-linking agent. Blocked hexamethylene diisocyanate isocyanurate, as a lubricant, oleic acid amide in a mixed solvent of water/ethanol (1/3), a binder in a solid content of 100 parts by mass, a conductive polymer in a solid content of 75 parts by mass, The cross-linking agent was added in an amount of 10 parts by mass in solid content, and the lubricant was added in an amount of 30 parts by mass in solid content, and the mixture was stirred for about 20 minutes and sufficiently mixed. In this way, a solution for the topcoat layer having an NV of about 0.4% (topcoat 1) was prepared.

<Preparation of resin layer film with topcoat layer (topcoat layer, first resin layer, adhesive layer, and second resin layer in this order)>
Corona treatment was applied to one surface of the resin layer film, and the topcoat layer solution was applied to the corona-treated surface so that the thickness after drying was 30 nm. A resin layer film with a topcoat layer (a topcoat layer, a first resin layer, an adhesive layer, and a second resin layer in this order) is produced by heating this coating material at 130° C. for 1 minute to dry it. did.

<Preparation of adhesive sheet (surface protection film)>
The acrylic adhesive solution is applied to the surface of the resin layer with the topcoat layer (topcoat layer, first resin layer, adhesive layer, second resin layer in this order) opposite to the topcoat layer, and 130 The adhesive layer having a thickness of 15 μm was formed by heating at 0° C. for 1 minute. Then, a silicone-treated surface of a polyethylene terephthalate film (thickness: 25 μm), which is a separator whose one surface was treated with silicone, was attached to the surface of the pressure-sensitive adhesive layer to prepare a pressure-sensitive adhesive sheet (surface protective film).

[Examples 3 to 5]
<Alkylene oxide (AO) group-containing acrylic compound>
120 parts by mass of toluene and 10 parts by mass of 2,2′-azobisisobutyronitrile were added to a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser, and nitrogen was added while gently stirring. Gas was introduced and the liquid temperature was adjusted to 85°C.
Subsequently, 50 parts by mass of 2-ethylhexyl acrylate, 50 parts by mass of ethoxy-diethylene glycol acrylate, and 10 parts by mass of α-methylstyrene dimer were gradually added over 2 hours while maintaining the liquid temperature at 85° C. to carry out a polymerization reaction. .. After the addition was completed, a polymerization reaction was further carried out for 1 hour while maintaining the liquid temperature at 85° C. to prepare a solution of an ethylene oxyside group-containing acrylic compound (solid content: 42 mass %).
The ethylene oxyside group-containing acrylic compound solution (solid content: 42% by mass) was dried at 130° C. for 1 hour to obtain an acrylic compound (solid content: 100% by mass) having an ethylenoxide group ratio of 23% by mass. The weight average molecular weight (Mw) of this acrylic compound was 3,000.

[Example 12]
<Preparation of urethane adhesive solution>
As the polyol, 100 parts by mass of Preminol S3015 (manufactured by Asahi Glass Co., Ltd., Mn=15000), which is a polyol having three hydroxyl groups (OH groups), and a trimethylolpropane/tolylene diisocyanate trimer adduct as a polyfunctional isocyanate compound ( Nippon Polyurethane Industry Co., Ltd., trade name: Coronate L) 13 parts by mass (solid content), polyoxyethylene glyceryl triisostearate as an alkylene oxide group-containing compound (Daiichi Kogyo Seiyaku Co., Ltd., trade name: Neugen GIS-320). , Number average molecular weight (Mn): 2000, ethylene oxide group content 53%) 1 part by mass, catalyst (manufactured by Nippon Kagaku Sangyo Co., Ltd., trade name: Nasem ferric iron) 0.04 parts by mass, ethyl acetate as a diluting solvent 210 parts by mass were mixed and stirred with a disper to obtain a urethane-based pressure-sensitive adhesive composition (solution).

<Preparation of adhesive sheet (surface protection film)>
The urethane adhesive solution is applied to the surface of the resin layer film (first resin layer, adhesive layer, second resin layer in this order) opposite to the first resin layer, and heated at 130° C. for 1 minute. Then, a pressure-sensitive adhesive layer having a thickness of 10 μm was formed. Then, a silicone-treated surface of a polyethylene terephthalate film (thickness: 25 μm), which is a separator whose one surface was treated with silicone, was attached to the surface of the pressure-sensitive adhesive layer to prepare a pressure-sensitive adhesive sheet (surface protective film).

[Comparative Example 3]
<Preparation of resin layer film (first resin layer, adhesive layer, and second resin layer in this order)>
30 parts by mass of 2-ethylhexyl acrylate (2EHA), 70 parts by mass of methyl acrylate (MA), and 10 parts by mass of acrylic acid (AA) were placed in a reaction vessel equipped with a cooling pipe, a nitrogen introducing pipe, a thermometer and a stirrer. , 2,2′ azobisisonitrile (0.2 parts by mass) and ethyl acetate were added, and the mixture was reacted under nitrogen gas flow at 60° C. for 6 hours with stirring to obtain an acrylic polymer solution having a weight average molecular weight of 1.1 million. It was To 100 parts by mass of the polymer solid content of the acrylic polymer solution, 1.0 part by mass of an epoxy compound [TETRAD-C] manufactured by Mitsubishi Gas Chemical Co., Ltd. and a urethane acrylate compound [UV-1700B manufactured by Nippon Synthetic Chemical Industry Co., Ltd.] ] 40 parts by mass, acrylate compound [Nippon Kayaku Co., KAYARAD DPCA-120] 40 parts by mass, 1-hydroxycyclohexyl phenyl ketone (trade name: IRGACURE 184) [Ciba Specialty Chemicals Co., Ltd.] 7 parts by mass And were added to prepare an acrylic adhesive 2 composition solution.

As a resin layer, a polyester resin film (manufactured by Toyobo Co., Ltd., trade name: E5000, thickness: 38 μm, tensile strength: 208 MPa) was coated with the above acrylic adhesive 2 composition solution and heated at 90° C. An adhesive layer having a thickness of 12 μm was formed.
After that, a polyester resin film (manufactured by Toyobo Co., Ltd., trade name: E5000, thickness: 38 μm, tensile strength: 208 MPa) is laminated on the adhesive layer so that the integrated light amount becomes 0.5 J/cm ² with a high pressure mercury lamp. Then, the adhesive layer was cured by irradiating it with ultraviolet rays to obtain a resin layer film having a thickness of 88 μm. The storage elastic modulus at 23° C. of the obtained adhesive layer was 6.7×10 ⁷ Pa.

[Examples 2-14 and Comparative Examples 1-2]
A pressure-sensitive adhesive sheet (surface protection film) was produced in the same manner as in Example 1 based on the formulation contents of Tables 1 to 3. When the antistatic component was added, it was added at the same timing as the AO group-containing compound. In Example 14, an adhesive sheet was prepared in the same manner as in Example 13. In Comparative Example 2, only the second resin layer shown in Table 4 was used instead of the resin layer film. In addition, the compounding quantity in the table showed the solid content.

The results of the above-described various measurements and evaluations of the pressure-sensitive adhesive sheets according to Examples and Comparative Examples are shown in Tables 4 to 6.

The abbreviations in Tables 2 and 3 will be described below.
2EHA: 2-ethylhexyl acrylate BA: n-butyl acrylate HEA: 2-hydroxyethyl acrylate AA: acrylic acid 25R-1: manufactured by ADEKA, trade name “ADEKA Pluronic 25R-1” (number average molecular weight 2800, ethylene oxide group Content rate 10% by mass)
17R-4: manufactured by ADEKA Co., Ltd., trade name "ADEKA Pluronic 17R-4" (number average molecular weight 2500, ethylene oxide group content 40 mass%)
HS-10: manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd., polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate, trade name "Aqualon HS-10" (molecular weight 798, ethylene oxide group content 55 mass%).
C/HX: hexamethylene diisocyanate isocyanurate (manufactured by Nippon Polyurethane Company, trade name: Coronate HX)
D201: Hexamethylene diisocyanate-based bifunctional isocyanate (manufactured by Asahi Kasei Corporation, trade name: Duranate D-201)
BMP: 1-butyl-3-methylpyridinium bis(trifluoromethanesulfonyl)imide (ionic liquid, liquid at 25°C, Wako Pure Chemical Industries, Ltd.)
LiTFSI: Lithium bis(trifluoromethanesulfonyl)imide (alkali metal salt, Kishida Chemical Co., Ltd.)
Polyester resin 25 μm: (manufactured by Teijin DuPont, trade name: G2, tensile strength: 261 MPa)
Polyester resin 38 μm: (manufactured by Toyobo Co., Ltd., trade name: E5000, tensile strength: 208 MPa)
Polyester resin 75 μm: (manufactured by Toyobo Co., Ltd., trade name: E5000, tensile strength: 188 MPa)

From the above evaluation results, in all the examples, the ratio of the desired thickness, the storage elastic modulus of the adhesive layer, the pressure-sensitive adhesive layer, by using a pressure-sensitive adhesive sheet, adhesive properties (such as adhesion) and pickup It was confirmed to be excellent. On the other hand, in the comparative example, a pressure-sensitive adhesive sheet having a desired thickness ratio and a pressure-sensitive adhesive layer was not used, and therefore, none of them could satisfy all the properties.

The pressure-sensitive adhesive sheet disclosed herein can be used to manufacture optical members used as components of liquid crystal display panels, plasma display panels (PDPs), organic electroluminescence (EL) displays, touch panel displays, etc. It is suitable as a pressure-sensitive adhesive sheet (surface protection film) for protection. In particular, pressure-sensitive adhesive sheets (optical pressure-sensitive adhesive sheets) applied to optical members such as polarizing plates (polarizing films) for liquid crystal display panels, wave plates, retardation plates, optical compensation films, brightness enhancement films, light diffusion sheets, and reflection sheets. ) Is useful as.

1 Adhesive sheet (surface protection film)
1A Surface of top coat layer 2 Polarizing plate 3 Acrylic plate 4 Fixing stand 5 Potential measuring device 6 First resin layer 7 Adhesive layer 8 Second resin layer 12 Resin layer film (first resin layer+adhesive layer+second) Resin layer)
14 Topcoat layer 20 Adhesive layer 20A Adhesive surface 50 Plain polarizing plate 60 Single-sided adhesive tape 62 Adhesive layer (adhesive surface)
64 Base Material 130 Double-sided Adhesive Tape 132 Stainless Steel Plate 160 Single-sided Adhesive Tape 162 Acrylic Adhesive (Adhesive Layer)
162A Adhesive surface 164 Resin layer film (first resin layer+adhesive layer+second resin layer)
T No. 31B tape G glass plate H height from center L load

Claims (6)

A first resin layer, an adhesive layer, a second resin layer, and a pressure-sensitive adhesive layer formed of a pressure-sensitive adhesive composition in this order,
A top coat layer is provided on the surface of the first resin layer opposite to the surface having the pressure-sensitive adhesive layer,
The top coat layer is formed from a polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder component, and a top coat layer composition containing an isocyanate compound as a crosslinking agent,
The value of the ratio of the thickness of the adhesive layer to the sum of the thickness of the first resin layer and the thickness of the second resin layer is 0.50 or less,
The storage elastic modulus of the adhesive layer at 23° C. is 1.0×10 ⁴ Pa or more and less than 5.0×10 ⁷ Pa,
The storage elastic modulus is measured by a dynamic viscoelasticity measuring device (ARES, manufactured by Rheometrics Co., Ltd.) under a measurement condition of a shear mode at a frequency of 1 Hz,
The adhesive layer has a thickness of 1 to 50 μm,
The adhesive layer is formed of an acrylic adhesive,
The pressure-sensitive adhesive composition, an acrylic adhesive, or, a urethane-based adhesive,
Furthermore, the pressure-sensitive adhesive composition contains an alkylene oxide group-containing compound,
The alkylene oxide group-containing compound is a compound having a (poly)ethylene oxide chain at least in part,
The pressure-sensitive adhesive sheet, wherein the alkylene oxide group-containing compound does not contain an organopolysiloxane having an oxyalkylene chain. The pressure-sensitive adhesive sheet according to claim 1, wherein the composition for the top coat layer further contains a fatty acid amide as a lubricant. At least one of the said resin layers is a polyester film, The adhesive sheet of Claim 1 or 2 characterized by the above-mentioned. The pressure-sensitive adhesive sheet according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive composition, characterized in that it contains an antistatic component. After the pressure-sensitive adhesive sheet is pressure-bonded to a polarizing plate, the pressure-sensitive adhesive sheet is peeled off from the polarizing plate surface,
Subsequently, an adhesive tape is applied to the surface of the polarizing plate to which the adhesive sheet has been adhered, and then the acrylic tape is removed from the surface of the polarizing plate at a peeling angle of 180° and a pulling speed of 300 mm/min. force, pressure-sensitive adhesive sheet according to any one of claims 1 to 4, characterized in that it is 3N / 19 mm or more. An optical member, characterized in that is bonded surface of the adhesive layer of the adhesive sheet according to any one of claims 1-5.

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