JP2019048985A - Adhesive composition, adhesive sheet, and optical member - Google Patents

Abstract

To provide an adhesive composition that can form an adhesive sheet having excellent shearing force and capable of suppressing curling of an adherend when the adhesive sheet is stuck to the adherend, and provide the adhesive sheet, and an optical member using the adhesive sheet stuck for surface protection.SOLUTION: An adhesive composition contains an onium salt with a melting point of 150°C or less, and a polymer with a glass transition temperature of 0°C or less as a base polymer. The onium salt is at least one kind selected from the group consisting of nitrogen-containing onium salt, sulfur-containing onium salt, and phosphorus-containing onium salt. The onium salt contains an onium cation having at least one alkyl group having 8 or more carbon atoms. An adhesive sheet has an adhesive layer on one or both sides of a support film.SELECTED DRAWING: None

Description

  The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet, and an optical member protected by the pressure-sensitive adhesive sheet.

  The pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition of the present invention is for protecting the surface of an optical member such as a polarizing plate, a wave plate, a retardation plate, an optical compensation film, a reflective sheet, and a brightness enhancement film used for liquid crystal displays. Is useful as a surface protection film used in

  In recent years, transport of optical parts and electronic parts and mounting on printed circuit boards have been carried out in a state in which individual parts are packaged in a predetermined sheet or in a state in which an adhesive tape is attached. Among them, surface protective films are particularly widely used in the field of optical and electronic parts.

  The surface protective film is generally bonded to an adherend (target to be protected) through a pressure-sensitive adhesive applied to the support film side, and used for the purpose of preventing scratches and stains generated during processing and conveyance of the adherend. (Patent Document 1). For example, a panel of a liquid crystal display is formed by bonding an optical member such as a polarizing plate or a wave plate to a liquid crystal cell via an adhesive. In these optical members, the surface protective film is bonded via an adhesive to prevent scratches and stains generated during processing and conveyance of the adherend.

  When attached to an adherend (polarizing plate etc.), unnecessary curl or unintended curl (curled back with curl) in the adherend (polarizing plate etc.) to which the surface protective film is attached. Curl so as not to cause a phenomenon such as a phenomenon in which a flat plate is entirely warped to one side or a phenomenon in which a flat plate is undulated as a whole. Tunability has been sought. Unnecessary curling and unintended curling may result in poor handleability, and problems such as entrapment of air bubbles may occur when attaching an adherend such as a polarizing plate to a liquid crystal cell, for example.

  In addition, when curling occurs on a flat adherend, the pressure-sensitive adhesive layer of the surface protective film bonded to the adherend is subjected to a force associated with curling in the shear direction, and this force adheres to the adherend. Since a slip, a shift, etc. arise gradually between a body and an adhesive layer, the improvement of a shear force is calculated | required.

Unexamined-Japanese-Patent No. 9-165460

  Therefore, the object of the present invention is to form a pressure-sensitive adhesive sheet which is excellent in shear force and capable of suppressing curling of the adherend when it is bonded to the adherend in order to solve the problems in the conventional pressure-sensitive adhesive sheet. The present invention is to provide a pressure-sensitive adhesive composition that can be used, the pressure-sensitive adhesive sheet, and an optical member formed by applying the pressure-sensitive adhesive sheet for surface protection use.

  That is, the pressure-sensitive adhesive composition of the present invention comprises an onium salt having a melting point of 150 ° C. or less, and a polymer having a glass transition temperature of 0 ° C. or less as a base polymer, and the onium salt is a nitrogen-containing onium salt It is at least one selected from the group consisting of sulfur-containing onium salts and phosphorus-containing onium salts, and the onium salt contains an onium cation having at least one alkyl group having 8 or more carbon atoms. .

  The pressure-sensitive adhesive composition of the present invention preferably contains a compound having an alkylene oxide group having a number average molecular weight of 10,000 or less.

  In the pressure-sensitive adhesive composition of the present invention, the compound having an alkylene oxide group is preferably an organopolysiloxane having an alkylene oxide group.

  In the pressure-sensitive adhesive composition of the present invention, the polymer having a glass transition temperature of 0 ° C. or less is preferably a (meth) acrylic polymer having a hydroxyl group and a carboxyl group.

The pressure-sensitive adhesive sheet of the present invention is a pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer formed of the pressure-sensitive adhesive composition on one side or both sides of a support film, and 1 cm ² of the pressure-sensitive adhesive area is attached to a TAC polarizing plate It is preferable that the shear force at the time of peeling in a shearing direction at a peeling speed of 0.06 m / min after putting together and peeling for 30 minutes at 23 ° C. is 8.5 N / cm ² or more.

  The pressure-sensitive adhesive sheet of the present invention has an antistatic layer on one side of the support film opposite to the pressure-sensitive adhesive layer, the antistatic layer comprising polyaniline sulfonic acid as a conductive polymer component, polyester resin as a binder, It is preferable to form from the antistatic agent composition which contains an isocyanate type crosslinking agent as a crosslinking agent.

  In the pressure-sensitive adhesive sheet of the present invention, the antistatic agent composition preferably further contains a fatty acid amide as a lubricant.

  It is preferable that the optical member of this invention is protected by the said adhesive sheet.

  Since the pressure-sensitive adhesive sheet formed of the pressure-sensitive adhesive composition of the present invention is excellent in shear force, it is possible to suppress unnecessary curling and unintended curling in the adherend when laminated to the adherend Yes, it is useful.

Schematic of the potential measurement unit

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

<Whole structure of adhesive sheet (surface protection film)>
The pressure-sensitive adhesive sheet (surface protective film) of the present invention is generally referred to as a pressure-sensitive adhesive sheet, a pressure-sensitive adhesive tape, a pressure-sensitive adhesive label, a pressure-sensitive adhesive film, etc., and in particular, an optical component (for example, a liquid crystal such as a polarizing plate or a wavelength plate) It is suitable as a surface protection film which protects the surface of an optical component at the time of processing and conveyance of an optical component used as a display panel component. The pressure-sensitive adhesive layer in the pressure-sensitive adhesive sheet is typically formed continuously, but is not limited to such a form, and is, for example, an adhesive formed in a regular or random pattern such as dot-like or stripe-like It may be an agent layer. In addition, the pressure-sensitive adhesive sheet disclosed herein may be in a roll shape or in a sheet shape.

  As a typical structural example of the pressure-sensitive adhesive sheet (surface protective film) disclosed herein, one having a pressure-sensitive adhesive layer on one side or both sides of a support film (base material), or antistatic provided on one side of the support film There is a layer comprising a pressure-sensitive adhesive layer provided on the surface of the support film opposite to the antistatic layer. The pressure-sensitive adhesive sheet is used by sticking the pressure-sensitive adhesive layer to an adherend (a protection target, for example, the surface of an optical component such as a polarizing plate). The pressure-sensitive adhesive sheet before use (that is, before application to the adherend) is protected by the release liner whose surface (adhesion surface to the adherend) is at least the release side of the pressure-sensitive adhesive layer. It may be in the form of Alternatively, the pressure-sensitive adhesive layer may be in contact with the back surface of the support film (the surface of the antistatic layer) to protect the surface by being wound in a roll.

<Adhesive composition>
The pressure-sensitive adhesive composition of the present invention comprises an onium salt having a melting point of 150 ° C. or less and a polymer having a glass transition temperature of 0 ° C. or less as a base polymer, and the onium salt is a nitrogen-containing onium salt, a sulfur-containing It is at least one selected from the group consisting of an onium salt and a phosphorus-containing onium salt, and the onium salt contains an onium cation having at least one alkyl group having 8 or more carbon atoms. As the pressure-sensitive adhesive composition, as long as it contains an onium salt having a melting point of 150 ° C. or less and a polymer having a glass transition temperature (Tg) of 0 ° C. or less as a base polymer, It can be used without particular limitation. For example, acrylic pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives, synthetic rubber-based pressure-sensitive adhesives, natural rubber-based pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives and the like can also be used. Among them, the acrylic pressure-sensitive adhesive is a preferred embodiment particularly in terms of easy control of adhesive properties.

  In the present invention, the polymer having a glass transition temperature (Tg) of 0 ° C. or less is preferably a (meth) acrylic polymer, and is a (meth) acrylic polymer having a hydroxyl group and a carboxyl group. , More preferred. By using a polymer having a glass transition temperature (Tg) of 0 ° C. or less, it becomes possible to design an adhesive having excellent adhesive properties, and by using the (meth) acrylic polymer, control of adhesive properties is possible. Is easily possible and is a preferred embodiment. Further, by using the (meth) acrylic polymer having the hydroxyl group and the carboxyl group, the hydroxyl group can easily control the crosslinking, and the carboxyl group improves the shear force. In addition, since it is possible to prevent an increase in adhesive strength over time, this is a preferable embodiment. In particular, by using the (meth) acrylic polymer having the hydroxyl group and the carboxyl group, the shear force of the pressure-sensitive adhesive (layer) is improved to bond the pressure-sensitive adhesive to the adherend, Curling based on the adherend can be suppressed, and the occurrence of slippage or deviation between the pressure-sensitive adhesive and the adherend (interface) can be suppressed, which is preferable.

  In the present invention, although a polymer having the glass transition temperature (Tg) of 0 ° C. or less is contained as a base polymer, a polymer having the glass transition temperature (Tg) of 0 ° C. or less is contained in 100% by mass of the base polymer. It is a more preferable aspect that it is 100 mass%. Moreover, the (meth) acrylic polymer in the present invention refers to an acrylic polymer and / or a methacrylic polymer, and the (meth) acrylate refers to an acrylate and / or a methacrylate.

  Moreover, it is preferable that the said (meth) acrylic-type polymer contains the said hydroxyl group containing (meth) acrylic-type monomer as a monomer component. The use of the hydroxyl group-containing (meth) acrylic monomer makes it easy to control the crosslinking of the pressure-sensitive adhesive composition, which in turn improves the wettability by flow and balances the cohesion and shear force of the pressure-sensitive adhesive (layer). It becomes easy to control. Furthermore, when an antistatic agent is added to the pressure-sensitive adhesive, unlike a carboxyl group or a sulfonate group which generally acts as a crosslinking site, the hydroxyl group is appropriate with an onium salt having a melting point of 150 ° C. or less which is an antistatic agent. Since they have an interaction, they can also suitably operate in terms of antistatic properties.

  In the present invention, the hydroxyl group-containing (meth) acrylic monomer is preferably contained in an amount of 0.5 to 15% by mass, more preferably 0. 5 to 15% by mass with respect to the total amount of monomer components constituting the (meth) acrylic polymer. It is 6 to 7% by mass, more preferably 0.7 to 4.99% by mass, and most preferably 1.0 to 3.9% by mass. Within the above range, the balance between the wettability of the pressure-sensitive adhesive composition and the cohesion of the pressure-sensitive adhesive (layer) and the shear force can be easily controlled, which is preferable. Further, in order to develop good charging characteristics with a smaller blending amount of the onium salt, it is more effective to use a smaller blending amount of the hydroxyl group-containing (meth) acrylic monomer.

  Examples of the hydroxyl group-containing (meth) acrylic monomers 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-hydroxy lauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide and the like. In addition, as said hydroxyl group containing (meth) acrylic-type monomer, you may use independently and may use 2 or more types as a monomer component.

  Moreover, it is preferable that the said (meth) acrylic-type polymer contains the said carboxyl group-containing (meth) acrylic-type monomer as a monomer component. By using the carboxyl group-containing (meth) acrylic monomer, it is possible to suppress the increase in the adhesive strength of the pressure-sensitive adhesive sheet (adhesive layer) with time, and the removability, the adhesive strength increase preventing property, and the workability. In addition to the cohesion of the pressure-sensitive adhesive layer, it is also excellent in shear force.

  In the present invention, the carboxyl group-containing (meth) acrylic monomer is preferably contained in an amount of 0.005 to 0.5% by mass, more preferably the total amount of monomer components constituting the (meth) acrylic polymer. It is 0.006 to 0.4% by mass, more preferably 0.008 to 0.3% by mass, and most preferably 0.01 to 0.2% by mass. Within the above range, it is possible to suppress an increase in adhesive strength over time, and to be excellent in removability, adhesive strength increase prevention property, and workability. In addition to the cohesion of the pressure-sensitive adhesive layer, it is also excellent in shear force. When a large number of acid functional groups such as carboxyl groups having a large polar action are present, the acid functional group such as carboxyl group and the above onium can be used when an onium salt having a melting point of 150 ° C. or less that can be used as an antistatic agent is blended. The interaction between the salts and the like interferes with ion conduction, which lowers the conduction efficiency, which may make it impossible to obtain sufficient antistatic properties, which is not preferable.

  Examples of the carboxyl group-containing (meth) acrylic monomer include (meth) acrylic acid, carboxylethyl (meth) acrylate, carboxylpentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, and the like. -(Meth) acryloyloxypropylhexahydrophthalic acid, 2- (Meth) acryloyloxyethyl phthalic acid, 2- (Meth) acryloyloxyethylsuccinic acid, 2- (Meth) acryloyloxyethylmaleic acid, carboxy Polycaprolactone mono (meth) acrylate, 2- (meth) acryloyloxyethyl tetrahydrophthalic acid and the like can be mentioned. In addition, as said carboxyl group-containing (meth) acrylic-type monomer, you may use independently and may use 2 or more types as a monomer component.

  In the present invention, it is preferable that the (meth) acrylic polymer has, as a monomer component, a (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, and more preferably 4 to 14 carbon atoms. (Meth) acrylic monomers having an alkyl group of As a (meth) acrylic-type monomer which has the said C1-C14 alkyl group, you may use independently, and 2 or more types may be used as a monomer component.

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

  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 (Meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, etc. Preferred are (meth) acrylates having an alkyl group having 6 to 14 carbon atoms. By using a (meth) acrylate having an alkyl group having 6 to 14 carbon atoms, it becomes easy to control the adhesion to the adherend to a low level, and the removability becomes excellent.

  In the present invention, 50 to 99 mass% of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms is contained with respect to the total amount of monomer components constituting the (meth) acrylic polymer Preferably, it is 60 to 98.8% by mass, more preferably 70 to 98.6% by mass, and most preferably 80 to 98.4% by mass. By being in the said range, an adhesive composition has appropriate wettability and is excellent also in the cohesion force of an adhesive (layer), and is preferable.

  In addition, as the other polymerizable monomer component, the (meth) acrylic polymer is prepared such that the glass transition temperature (Tg) is 0 ° C. or less (usually −100 ° C. or more) because the adhesion performance can be easily balanced. The polymerizable monomer for adjusting the Tg and the releasability can be used as long as the effects of the present invention are not impaired.

  Other than the hydroxyl group-containing (meth) acrylic monomer, the carboxyl group-containing (meth) acrylic monomer, and the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms used in the (meth) acrylic polymer These other polymerizable monomers can be used without particular limitation as long as the properties of the present invention are not impaired. For example, components such as cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, and cohesion and heat resistance improving components, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, vinyl ether monomers, etc. A component having a functional group which works as adhesion (adhesive) power improvement or a crosslinking base point, and a peeling force adjusting component such as an alkylene oxide group-containing monomer 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 and vinyl laurate.

  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, diethyl acrylamide, N-vinyl pyrrolidone, N, N-dimethyl acrylamide, N, N- dimethyl methacrylamide, N, N- diethyl acrylamide, N, N- diethyl Methacrylamide, N, N'-methylenebisacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, diacetone acrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide N-t-butyl (meth) acrylamide, N, N-dipropyl acrylamide, N, N-diisopropyl (meth) acrylamide, N, N-dibutyl (meth) acrylamide, N-ethyl-N-methyl (Meth) acrylamide, N-methyl-N-propyl (meth) acrylamide, N-methyl-N-isopropyl (meth) acrylamide, N-methylol acrylamide, diacetone acrylamide, N-vinyl acetamide, N, N'-methylene bis Acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-dipropylaminopropyl (meth) acrylamide, N, N-diisopropylaminopropyl (meth) acrylamide, N-ethyl-N-methylaminopropyl (meth) Acrylamide, N-methyl-N-propylaminopropyl (meth) acrylamide, N-methyl-N-isopropylaminopropyl (meth) acrylamide, N-vinylacetamide, N-vinyl-N-methylacetamide, N Methoxymethyl (meth) acrylamide, N- ethoxyethyl (meth) acrylamide, N- butoxymethyl (meth) acrylamide, such as N- vinyl caprolactam.

  Examples of the imide group-containing monomer include cyclohexyl maleimide, isopropyl maleimide, N-cyclohexyl maleimide, itaconimide and the like.

  Examples of the amino group-containing monomer include aminoethyl (meth) acrylate, N, N-dimethylaminomethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) ) Acrylate, N, N-Dimethylaminoisopropyl (meth) acrylate, N, N-Dimethylaminobutyl (meth) acrylate, N, N-diethylaminomethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N -Ethyl-N-methylaminoethyl (meth) acrylate, N-methyl-N-propylaminoethyl (meth) acrylate, N-methyl-N-isopropylaminoethyl (meth) acrylate, N, N-dibutylaminoethyl (meth) ) Acrylate, t- Chill aminoethyl (meth) acrylate, and (meth) acryloyl morpholine and the like.

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

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

  Examples of the alkylene oxide group-containing monomer include methoxy-polyethylene glycol (meth) acrylate type such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) acrylate, ethoxy-diethylene glycol (meth) acrylate, and ethoxy- Ethoxy-polyethylene glycol (meth) acrylate type such as triethylene glycol (meth) acrylate, butoxy-polyethylene glycol (meth) acrylate type such as butoxy-diethylene glycol (meth) acrylate, butoxy-triethylene glycol (meth) acrylate, phenoxy- Diethylene glycol (meth) acrylate, phenoxy-triethylene glycol (meth) acrylate Methoxy-polypropylene glycol (meth) such as phenoxy-polyethylene glycol (meth) acrylate type, 2-ethylhexyl-polyethylene glycol (meth) acrylate, nonylphenol-polyethylene glycol (meth) acrylate type, methoxy-dipropylene glycol (meth) acrylate An acrylate type etc. are mention | raise | lifted.

  In the present invention, the above-mentioned carboxyl group-containing (meth) acrylic monomers, hydroxyl group-containing (meth) acrylic monomers, and other polymerizable monomers other than (meth) acrylic monomers having an alkyl group having 1 to 14 carbon atoms It is preferable that it is 0-40 mass% in the monomer component whole quantity (all the monomer components) which comprises the said (meth) acrylic-type polymer, and it is more preferable that it is 0-30 mass%. By using the other polymerizable monomers in the above range, good interaction with an onium salt having a melting point of 150 ° C. or less, which can be used as an antistatic agent, and good removability can be appropriately adjusted. .

  When the nitrogen-containing monomer such as the amide group-containing monomer is used as the monomer component of the (meth) acrylic polymer as the other polymerizable monomer, it is preferable to contain 0.5 to 20% by mass More preferably, it is 0.5-10 mass%, More preferably, it is 1-4 mass%. By using the (meth) acrylic polymer containing the nitrogen-containing monomer, the cohesion of the obtained pressure-sensitive adhesive (layer) is improved, an excellent shear force can be expressed, and further, curl control (curl controllability) ) Is supposed to be high. In addition, curl controllability at high temperatures can be improved, which is useful. Furthermore, since the onium having the melting point of 150 ° C. or less is coordinated to the nitrogen atom contained in the nitrogen-containing monomer, it is presumed that the onium salt is less likely to bleed and an excellent shearing force can be realized. In addition, when lower adhesive force is calculated | required as an adhesive sheet, it is more preferable for there to be few content of a nitrogen containing monomer.

  The weight average molecular weight (Mw) of the (meth) acrylic polymer is preferably 100,000 to 5,000,000, more preferably 200,000 to 4,000,000, further preferably 300,000 to 3,000,000, and most preferably 400,000 to 700,000. It is. When the Mw is less than 100,000, the adhesive force of the obtained pressure-sensitive adhesive layer tends to be reduced to cause adhesive residue. On the other hand, when the Mw exceeds 5,000,000, the flowability of the polymer decreases and the wetting to the adherend (for example, a polarizing plate as an optical member) becomes insufficient, and the pressure-sensitive adhesive layer of the adherend and the adhesive sheet It tends to be a cause of the swelling generated between (the pressure-sensitive adhesive composition layer). In addition, Mw says what was obtained by measuring by gel permeation chromatography (GPC).

  The polymer having a glass transition temperature (Tg) of 0 ° C. or less (eg, the (meth) acrylic polymer) has a Tg of 0 ° C. or less, preferably −10 ° C. or less, and more preferably −40. C. or lower, more preferably -60.degree. C. or lower (usually -100.degree. C. or higher). When the Tg is higher than 0 ° C., the polymer does not flow easily, and, for example, the wetting to the adherend (eg, a polarizing plate as an optical member) becomes insufficient, and the adherend and the pressure-sensitive adhesive layer (pressure-sensitive adhesive composition) Tends to cause blisters to occur between Moreover, the adhesive composition which is excellent in the wettability to a to-be-adhered body and light releasability becomes is easy to be obtained by making Tg 0 degrees C or less. The Tg of the polymer having a glass transition temperature (Tg) of 0 ° C. or less (for example, the (meth) acrylic polymer) can be adjusted within the above range by appropriately changing the monomer components and the composition ratio used. .

  The polymerization method of the polymer having a glass transition temperature (Tg) of 0 ° C. or less (for example, the (meth) acrylic polymer) used in the present invention is not particularly limited, and solution polymerization, emulsion polymerization, bulk polymerization The polymerization can be carried out by a known method such as suspension polymerization, but solution polymerization is a more preferable embodiment from the viewpoints of workability in particular and characteristics such as low contamination to the adherend. Further, the polymer to be obtained may be any of random copolymer, block copolymer, alternating copolymer, graft copolymer and the like.

  The pressure-sensitive adhesive composition of the present invention comprises an onium salt having a melting point of 150 ° C. or less, and the onium salt is at least selected from the group consisting of nitrogen-containing onium salts, sulfur-containing onium salts, and phosphorus-containing onium salts. The onium salt is characterized by containing an onium cation having at least one alkyl group having 8 or more carbon atoms. By using the onium salt having a melting point of 150 ° C. or less (preferably, 100 ° C. or less, more preferably 30 ° C. or more and 60 ° C. or less), dispersion in the base polymer becomes easy, which is a preferable embodiment. In addition, when the onium salt is at least one selected from the group consisting of a nitrogen-containing onium salt, a sulfur-containing onium salt, and a phosphorus-containing onium salt, it is possible to exhibit excellent charging characteristics, and further, When the onium salt contains an onium cation having at least one alkyl group having 8 or more carbon atoms, coexistence of shear properties and charging properties becomes possible, which is preferable.

  In the onium salt having a melting point of 150 ° C. or less, the onium cation having at least one alkyl group having 8 or more carbon atoms constituting the onium salt is preferably an alkyl group having 9 or more carbon atoms, more preferably It is an onium cation having an alkyl group having 10 or more carbon atoms.

  Among the above onium salts, as a nitrogen-containing onium salt, 1-octyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-decyl-3-methylimidazolium hexa Fluorophosphate, 1-dodecyl-3-methylimidazolium iodide, 1-dodecyl-3-methylimidazolium bromide, 1-dodecyl-3-methylimidazolium hexafluorophosphate, 1-tetradecyl-3-methylimidazolium Hexafluorophosphate, 1-hexadecyl-3-methylimidazolium tetrafluoroborate, 1-hexadecyl-3-methylimidazolium hexafluorophosphate, 1-hexadecyl-3-methylimidazoliumbi (Trifluoromethanesulfonyl) imide, 1-octylpyridinium hexafluorophosphate, 1-octylpyridinium dodecylbenzenesulfonate, 1-octyl-3-methylpyridinium hexafluorophosphate, 1-octyl-4-methylpyridinium hexafluorophosphate 1-nonylpyridinium hexafluorophosphate 1-dodecylpyridinium thiocyanate 1-dodecyl-2-methylpyridinium hexafluorophosphate 1-hexadecylpyridinium bis (trifluoromethanesulfonyl) imide methyltrioctylammonium triflate methyltri Octylammonium trifluoromethanesulfonate, tetraoctylammonium bromide, hexadecyl Such as trimethyl ammonium hexafluorophosphate and the like.

  Among the above onium salts, examples of the sulfur-containing onium salt include diethyl tetradecyl sulfonium hexafluorophosphate and the like.

  Among the above onium salts, examples of the phosphorus-containing onium salt include tetraoctylphosphonium bromide, trihexyltetradecylphosphonium bromide, tributylhexadecylphosphonium bromide and the like.

  The content of the onium salt is preferably 0.1 to 4.9 parts by mass, more preferably 0.2 to 4 parts by mass, and 0.5 to 3 parts by mass with respect to 100 parts by mass of the base polymer. Is more preferable, and 0.7 to 1.4 parts by mass is the most preferable. It is preferable that the content falls within the above range, because it is easy to achieve both the antistatic property and the low staining property.

  The pressure-sensitive adhesive composition of the present invention preferably contains a compound having an alkylene oxide group having a number average molecular weight (Mn) of 10,000 or less. By using the compound which has the said alkylene oxide group, the adhesive composition excellent in the wettability to a to-be-adhered body can be obtained.

  As specific examples of the compound having an alkylene oxide group, for example, polyoxyalkylene alkylamine, polyoxyalkylene diamine, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene alkyl phenyl ether, polyoxyalkylene alkyl Nonionic surfactants such as ether, polyoxyalkylene alkyl allyl ether, polyoxyalkylene alkyl phenyl allyl ether; polyoxyalkylene alkyl ether sulfuric acid ester salt, polyoxyalkylene alkyl ether phosphoric acid ester salt, polyoxyalkylene alkyl phenyl ether Anionic surfactants such as sulfuric acid ester salts and polyoxyalkylene alkyl phenyl ether phosphate ester salts Agents; others, cationic surfactants having a polyalkylene oxide group (polyalkylene oxide chain), amphoteric surfactants, polyether compounds having a polyalkylene oxide group (including derivatives thereof), polyalkylene oxide groups And polyester compounds (and their derivatives), and acrylic compounds (and their derivatives) having a polyalkylene oxide group. Moreover, you may mix | blend with the said base polymer (for example, said (meth) acrylic-type polymer) as a compound which has the said alkylene oxide group using an alkylene oxide group containing monomer. The compounds having an alkylene oxide group may be used alone or in combination of two or more.

  Specific examples of the polyether compound having an alkylene oxide group include a block copolymer of polypropylene glycol (PPG) -polyethylene glycol (PEG), a block copolymer of PPG-PEG-PPG, and a block of PEG-PPG-PEG Copolymer etc. are mentioned. The derivative of the polyether compound having an alkylene oxide group is an oxypropylene group-containing compound having an etherified terminal (PPG monoalkyl ether, PEG-PPG monoalkyl ether, etc.), an oxypropylene group containing an acetylated terminal. Compounds (terminally acetylated PPG etc.) and the like can be mentioned.

  Moreover, the (meth) acrylate polymer which has an oxyalkylene group is mentioned as a specific example of the acrylic compound which has the said alkylene oxide group. The oxyalkylene group is preferably 1 to 50, more preferably 2 to 30, still more preferably 2 to 20, from the viewpoint that the added mole number of the oxyalkylene unit is coordinated with the onium salt as an antistatic agent. preferable. Further, the terminal of the oxyalkylene group may be a hydroxyl group as it is or may be substituted by 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 component (monomer unit), and specific examples of the (meth) acrylic acid alkylene oxide Examples include ethylene glycol group-containing (meth) acrylates, for example, methoxy-polyethylene glycol (meth) acrylate type such as methoxy-diethylene glycol (meth) acrylate, methoxy-triethylene glycol (meth) acrylate, ethoxy-diethylene glycol ( Ethoxy-polyethylene glycol (meth) acrylate type such as meta) acrylate, ethoxy-triethylene glycol (meth) acrylate, butoxy-diethylene glycol (meth) acrylate , Butoxy-polyethylene glycol (meth) acrylate type such as butoxy-triethylene glycol (meth) acrylate, phenoxy-polyethylene glycol (meth) acrylate such as phenoxy-diethylene glycol (meth) acrylate, phenoxy-triethylene glycol (meth) acrylate And 2-ethylhexyl-polyethylene glycol (meth) acrylate, nonylphenol-polyethylene glycol (meth) acrylate type, and methoxy-polypropylene glycol (meth) acrylate type such as methoxy-dipropylene glycol (meth) acrylate.

  Moreover, other monomer components other than the (meth) acrylic acid alkylene oxide can be used as the monomer component. Specific examples of other monomer components include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate and isobutyl (meth) acrylate , Hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate , Isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, acrylate and / or methacrylate having an alkyl group of 1 to 14 carbon atoms Door and the like.

  Furthermore, as other monomer components other than the (meth) acrylic acid alkylene oxide, carboxyl group-containing (meth) acrylate, phosphoric acid group-containing (meth) acrylate, cyano group-containing (meth) acrylate, vinyl esters, aromatic vinyl Compound, acid anhydride group-containing (meth) acrylate, hydroxyl group-containing (meth) acrylate, amide group-containing (meth) acrylate, amino group-containing (meth) acrylate, epoxy group-containing (meth) acrylate, N-acryloyl morpholine, vinyl ether It is also possible to use a class or the like as appropriate.

  In a preferred embodiment, the compound having an alkylene oxide group is a compound having an (poly) ethylene oxide group at least in part. By blending the compound having the (poly) ethylene oxide group, the compatibility between the base polymer (for example, the (meth) acrylic polymer) and the antistatic component is improved, and bleeding to the adherend is suitably suppressed. As a result, a pressure-sensitive adhesive composition with low contamination is obtained. Among them, particularly when a PPG-PEG-PPG block copolymer is used, a pressure-sensitive adhesive composition excellent in low contamination can be obtained. In the above (poly) ethylene oxide group-containing compound, the mass of the (poly) ethylene oxide group in the entire compound is preferably 5 to 90% by mass, more preferably 5 to 85% by mass, still more preferably 5 to 80 % By weight, most preferably 5 to 75% by weight.

  The molecular weight of the compound having an alkylene oxide group is preferably 10,000 or less, more preferably 200 to 8,000, still more preferably 300 to 6,000, and particularly preferably 400 to 4,000, as the number average molecular weight (Mn). When Mn is more than 10,000, the compatibility with the base polymer (for example, the (meth) acrylic polymer) is reduced, and the pressure-sensitive adhesive layer tends to be whitened. When Mn is less than 200, contamination with the compound having an alkylene oxide group may easily occur. In addition, Mn means the value of polystyrene conversion obtained by the gel permeation chromatography method (GPC) here.

  In addition, specific examples of the above-mentioned compounds having an alkylene oxide group as commercial products include, for example, Adeka Pluronic 17R-4, Adeka Pluronic 25 R-1, Adeka Pluronic 25 R-2 (all manufactured by ADEKA Corporation), Emulgen 120 (all manufactured by JP) Kao Corporation) and the like.

  In the present invention, it is preferable that the compound having an alkylene oxide group is an organopolysiloxane having an alkylene oxide group. By using the organopolysiloxane, the surface free energy of the pressure-sensitive adhesive surface is reduced, and it is presumed that light peeling is realized at the time of high-speed peeling.

  As the organopolysiloxane, a known organopolysiloxane having an alkylene oxide group can be suitably used. For example, as a commercial product, the trade names X-22-4952, X-22-2427, X-22-6266, KF -6004, KF-889, KF-351A, KF-352A, KF-353L, KF- 355L, KF-615A, KF-945, KF-640, KF-642, KF-643, KF-6022 X-22-6191, X-22-4515, KF-6011, KF-6012, KF-6015, KF-6017, X-22-2516 (all manufactured by Shin-Etsu Chemical Co., Ltd.), BY16-201, SF8427, SF8428, FZ-2162, SH3749, FZ-77, L-7001, FZ-2104, FZ 2110, L-7002, FZ-2122, FZ-2164, FZ-2203, FZ-7001, SH8400, SH8700, SF8410, SF8422 (all manufactured by Toray Dow Corning), IM 22 (all manufactured by Asahi Kasei Wacker), TSF-4440, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4452, TSF-4460 (above, manufactured by Momentive Performance Materials, Inc.), BYK-333, BYK-307, BYK-377, BYK-UV 3500, BYK-UV 3570 (above, manufactured by Big Chemie Japan) and the like. These may be used alone or in combination of two or more.

  As said organopolysiloxane used by this invention, HLB (Hydrophile-Lipophile Balance) value is preferable 1-16, More preferably, it is 3-14. When the HLB value is out of the above range, the contamination of the adherend is deteriorated, which is not preferable.

  The content of the compound having an alkylene oxide group having a number average molecular weight of 10,000 or less is preferably 0.01 to 5 parts by mass, more preferably 0.03 to 1 with respect to 100 parts by mass of the base polymer. It is part by mass, more preferably 0.05 to 0.5 parts by mass, and most preferably 0.1 to 0.2 parts by mass. It is preferable that it is in the above-mentioned range because it is easy to achieve both of the antistatic property and the light releasability (removability). When the content is small, the effect of preventing bleeding of the antistatic component is reduced, and when the content is large, contamination by the compound having an alkylene oxide group may easily occur, which is not preferable.

  The pressure-sensitive adhesive composition of the present invention preferably contains a crosslinking agent. In the present invention, the pressure-sensitive adhesive layer can be formed using the pressure-sensitive adhesive composition. For example, in the case where the pressure-sensitive adhesive contains the (meth) acrylic polymer, crosslinking is carried out by appropriately adjusting the structural unit, the composition ratio, the selection and the addition ratio of the crosslinking agent, and the like of the (meth) acrylic polymer. A pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer) more excellent in heat resistance can be obtained.

  As the crosslinking 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 in particular, 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 crosslinking agent) include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), dimer acid diisocyanate, etc., cyclopentylene diisocyanate, cyclohexylene diisocyanate, isophorone diisocyanate Alicyclic isocyanates such as (IPDI), 2,4-tolylene diisocyanate, aromatic isocyanates such as 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate (XDI), allophanate bond, biuret bond of the isocyanate compound, Isocyanurate bond, uretdione bond, urea bond, carbodiimide bond, uretone imine bond, oxygen Polyisocynate modified product obtained by modifying the like trione bond. For example, as commercially available products, Takenate 300S, Takenate 500, Takenate D 165 N, Takenate D 178 N (above, Takeda Yakuhin Kogyo Co., Ltd.), Semidur T 80, Semidur L, Desmodur N 3400 (above, Sumika Bayer Urethane Co., Ltd.) And Millionate MR, Millionate MT, Coronate L, Coronate HL, Coronate HX (manufactured by Nippon Polyurethane Industry Co., Ltd.) and the like. These isocyanate compounds may be used alone or in combination of two or more. It is also possible to use a bifunctional isocyanate compound and a trifunctional or higher isocyanate compound in combination. By using a crosslinking agent in combination, it is possible to achieve both adhesiveness and repulsion resistance (adhesion to a curved surface), and it is possible to obtain a surface protection film having more excellent adhesion reliability.

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

  Examples of the melamine resin include hexamethylolmelamine. Examples of the aziridine derivative include commercially available HDU, TAZM, TAZO (manufactured by Mutual Pharmaceutical Co., Ltd.) and the like as commercial products.

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

  The content of the crosslinking agent used in the present invention is, for example, preferably 0.01 to 10 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer as a base polymer. The content is more preferably 8 to 8 parts by mass, further preferably 0.5 to 5 parts by mass, and most preferably 1.0 to 2.5 parts by mass. When the content is less than 0.01 parts by mass, the crosslinking formation by the crosslinking agent may be insufficient, the cohesive force of the obtained pressure-sensitive adhesive layer may be reduced, and sufficient heat resistance may not be obtained. It tends to cause adhesive residue. On the other hand, when the content exceeds 10 parts by mass, the cohesion of the polymer is large, the fluidity is reduced, and the wetting to the adherend (for example, the polarizing plate) becomes insufficient, and the adherend and the adhesive It tends to be a cause of the swelling generated between the layer (pressure-sensitive adhesive composition layer). Furthermore, when the amount of the crosslinking agent is large, the peeling chargeability tends to be lowered.

  The pressure-sensitive adhesive composition may further contain a crosslinking catalyst in order to promote any of the above-mentioned crosslinking reactions more effectively. As such a crosslinking catalyst, for example, tin-based catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris (acetylacetonato) iron, tris (hexane-2,4-dionato) iron, tris (heptane-2,4-dionato) ) Iron, Tris (heptane-3,5-dionato) iron, Tris (5-methylhexane-2,4-dionato) iron, Tris (octane-2,4-dionato) iron, Tris (6-methylheptane-2) (4,4-Dionato) iron, tris (2,6-dimethylheptane-3,5-dionato) iron, tris (nonane-2,4-dionato) 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), Dionato), tris (hexafluoroacetylacetonato) iron, tris (ethyl acetoacetate) iron, tris (acetoacetic acid-n-propyl) iron, tris (isopropyl acetoacetate) iron, tris (acetoacetic acid-n-butyl) Iron, Tris (acetoacetate-sec-butyl) iron, Tris (acetoacetate-tert-butyl) iron, Tris (propionyl acetate methyl) iron, Tris (propionyl acetate ethyl) iron, Tris (propionyl acetate-n-propyl) iron Tris (propionyl acetate isopropyl) 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, tris (diethyl malonate) iron, trimethoxyiron, Iron-based catalysts such as triethoxy iron, triisopropoxy iron and ferric chloride can be used. These crosslinking catalysts may be used alone or in combination of two or more.

  The content of the crosslinking catalyst is not particularly limited, but for example, about 0.0001 to 1 parts by mass is preferable as a base polymer with respect to 100 parts by mass of the (meth) acrylic polymer, and 0.001 to 0. 5 parts by mass is more preferable. When the pressure-sensitive adhesive layer is formed within the above range, the rate of the crosslinking reaction is fast, and the pot life of the pressure-sensitive adhesive composition becomes long, which is a preferable embodiment.

  Furthermore, the pressure-sensitive adhesive composition may contain an acrylic oligomer. The weight average molecular weight (Mw) of the acryl oligomer is preferably 1000 or more and less than 30000, more preferably 1500 or more and less than 20000, and still more preferably 2000 or more and less than 10000. Adhesiveness (adhesion) property falls that Mw is 30000 or more. Moreover, since it becomes a low molecular weight as Mw is less than 1000, the fall of the adhesive force of an adhesive sheet may be caused.

As the acrylic oligomer, (meth) acrylic acid ester monomers can be used, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, (meth) Butyl acrylate, isobutyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, (Meth) acrylic acid 2-ethylhexyl, (meth) acrylic acid heptyl, (meth) acrylic acid octyl, (meth) acrylic acid isooctyl, (meth) acrylic acid nonyl, (meth) acrylic acid isononyl, (meth) acrylic acid Decyl, (meth) acrylate isodecyl, (meth) acrylate undecyl , (Meth) such as acrylic acid dodecyl (meth) acrylic acid alkyl ester;
(Meth) acrylic acid aryl esters such as phenyl (meth) acrylate, benzyl (meth) acrylate;
The (meth) acrylic acid ester etc. which are obtained from a terpene compound derivative alcohol can be mentioned.
Further, as the acrylic oligomer, (meth) acrylic monomers having an alicyclic structure can be used. For example, dicyclopentanyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyl oxyethyl methacrylate, dicyclopentanyl Oxyethyl acrylate, tricyclopentanyl methacrylate, tricyclopentanyl acrylate, 1-adamantyl methacrylate, 1-adamantyl acrylate, 2-methyl-2-adamantyl methacrylate, 2-methyl-2-adamantyl acrylate, 2-ethyl-2-adamantyl acrylate Examples include (meth) acrylic acid esters such as adamantyl methacrylate and 2-ethyl-2-adamantyl acrylate. Such (meth) acrylic monomers can be used alone or in combination of two or more.

  In addition to the (meth) acrylic monomer component (unit), the acrylic oligomer is obtained by copolymerizing another monomer component (copolymerizable monomer) copolymerizable with the (meth) acrylic monomer. It is also possible.

  Furthermore, the pressure-sensitive adhesive composition can contain, as a crosslinking retarder, a compound that produces keto-enol tautomerism. For example, in a pressure-sensitive adhesive composition containing a crosslinking agent or in a pressure-sensitive adhesive composition that can be used in combination with a crosslinking agent, an embodiment including a compound that produces the keto-enol tautomerism can be preferably employed. Thereby, the excessive viscosity rise and gelatinization of the adhesive composition after mix | blending a crosslinking agent can be suppressed, and the effect of extending the pot life of an adhesive composition may be implement | achieved. When at least an isocyanate compound is used as the crosslinker, it is particularly significant to include a compound that produces keto-enol tautomerism. This technique can be preferably applied, for example, when the pressure-sensitive adhesive composition is in the form of an organic solvent solution or a solventless form.

  As a compound which produces the said keto- enol tautomerism, various (beta) -dicarbonyl compounds can be used. Specific examples thereof include acetylacetone, 2,4-hexanedione, 3,5-heptanedione, 2-methylhexane-3,5-dione, 6-methylheptane-2,4-dione, 2,6-dimethylheptane-. Β-diketones such as 3,5-dione; acetoacetic acid esters such as methyl acetoacetate, ethyl acetoacetate, isopropyl acetoacetate, tert-butyl acetoacetate; ethyl propionyl acetate, ethyl propionyl acetate, isopropyl propionyl acetate, propionyl acetate Propionyl acetates such as tert-butyl; isobutyryl acetates such as ethyl isobutyryl acetate, ethyl isobutyryl acetate, isopropyl isobutyryl acetate, tert-butyl isobutyryl acetate; malonic esters such as methyl malonate and ethyl malonate; And the like. Among them, preferred compounds include acetylacetone and acetoacetic acid esters. The compounds that produce such keto-enol tautomerism may be used alone or in combination of two or more.

  The content of the compound that produces the keto-enol tautomerism can be, for example, 0.1 to 20 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer as a base polymer, and is usually Is suitably 0.5 to 15 parts by mass (e.g. 1 to 10 parts by mass). When the amount of the compound is too small, it may be difficult to exhibit a sufficient use effect. On the other hand, if the compound is used more than necessary, it may remain in the pressure-sensitive adhesive layer and reduce the cohesion.

  Furthermore, the pressure-sensitive adhesive composition of the present invention may contain other known additives. For example, colorants, powders such as pigments, surfactants, plasticizers, tackifiers, low molecular weight Polymer, surface lubricant, leveling agent, antioxidant, corrosion inhibitor, light stabilizer, UV absorber, polymerization inhibitor, silane coupling agent, inorganic or organic filler, metal powder, particulate, foil It can add suitably according to the use which uses things etc.

  The pressure-sensitive adhesive sheet of the present invention preferably has a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition (cross-linking the pressure-sensitive adhesive composition formed) on one side or both sides of a support film. The crosslinking of the pressure-sensitive adhesive composition is generally carried out after the application of the pressure-sensitive adhesive composition, but it is also possible to transfer the pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition after crosslinking onto a support film or the like. The method for forming the pressure-sensitive adhesive layer on the support film is not particularly limited. For example, the pressure-sensitive adhesive composition is applied to the support film, and the polymerization solvent and the like are dried and removed to form the pressure-sensitive adhesive layer on the support film. It is produced by forming. Thereafter, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer, adjusting the crosslinking reaction, and the like. Moreover, when apply | coating an adhesive composition on a support film and producing an adhesive sheet, 1 or more types of solvents other than a polymerization solvent are newly added in the said adhesive composition so that it can apply | coat uniformly on a support film. You may add to

<Support film>
Although the resin material which comprises the said support film can be especially used without limitation as said support film, For example, transparency, mechanical strength, heat stability, moisture shielding property, isotropy, flexibility, It is preferable to use one excellent in characteristics such as dimensional stability. In particular, when the support film has flexibility, the pressure-sensitive adhesive composition can be applied by a roll coater or the like, and can be wound into a roll, which is useful.

  Examples of the support film (base material) include polyester-based polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate; cellulose-based polymers such as diacetylcellulose and triacetylcellulose; polycarbonate-based polymers; An acrylic polymer such as methyl methacrylate; a plastic film composed of a resin material having as a main resin component (a main component in the resin component, typically 50% by mass or more) as the support film It can be used preferably. As other examples of the resin material, styrene-based polymers such as polystyrene and acrylonitrile-styrene copolymer; olefin-based polymers such as polyethylene, polypropylene, polyolefin having a cyclic to norbornene structure, ethylene-propylene copolymer and the like; An example is a vinyl chloride-based polymer; an amide-based polymer such as nylon 6, nylon 6, 6 or aromatic polyamide; or the like as a resin material. Still other examples of the resin material include imide polymers, sulfone polymers, polyethersulfone polymers, polyetheretherketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers And arylate polymers, polyoxymethylene polymers, epoxy polymers and the like. It may be a support film consisting of a blend of two or more of the above mentioned polymers.

  As the support film, a plastic film made of a transparent thermoplastic resin material can be preferably employed. Among the plastic films, it is a more preferable aspect to use a polyester film. Here, the polyester film is mainly composed of a polymer material (polyester resin) having a main skeleton based on an ester bond, such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate etc. Say. Such a polyester film has excellent properties as a support film of a pressure-sensitive adhesive sheet, such as excellent optical properties and dimensional stability, and has a property of being easily charged as it is.

  If necessary, various additives such as an antioxidant, an ultraviolet absorber, a plasticizer, a colorant (pigment, dye, etc.) may be blended in the resin material constituting the support film. The first surface (the surface on which the antistatic layer is provided) of the polyester film is known or commonly used, such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, application of an undercoat, etc. Surface treatment may be applied. Such surface treatment may be, for example, treatment for enhancing the adhesion between the support film and the antistatic layer. A surface treatment may be preferably employed in which a polar group such as a hydroxyl group is introduced to the surface of the support film. The same surface treatment as described above may be applied to the second surface of the support film (the surface on which the pressure-sensitive adhesive layer is formed). Such surface treatment may be treatment for enhancing the adhesion between the film and the pressure-sensitive adhesive layer (the anchoring property of the pressure-sensitive adhesive layer).

  The pressure-sensitive adhesive sheet of the present invention may also have an antistatic layer on a support film, but when it has an antistatic function, it further uses a plastic film which has been subjected to an antistatic treatment as the support film. It is also possible. By using the said support film, since the electrostatic charge of the adhesive sheet itself at the time of peeling is suppressed, it is preferable. Further, the support film is a plastic film, and by subjecting the plastic film to an antistatic treatment, charging of the pressure-sensitive adhesive sheet itself can be reduced and an antistatic performance to an adherend can be excellent. In addition, there is no restriction | limiting in particular as a method of providing an antistatic function, A conventionally well-known method can be used, For example, antistatic resin, an electroconductive polymer, an electroconductive substance which consists of an antistatic agent and a resin component The method of applying the conductive resin to be contained, the method of depositing or plating the conductive substance, the method of kneading the antistatic agent and the like, and the like can be mentioned.

  The thickness of the support film is usually 5 to 200 μm, preferably about 10 to 100 μm. It is preferable for the thickness of the support film to be in the above-mentioned range, since the bonding workability to the adherend and the peeling workability from the adherend are excellent.

  Moreover, as a formation method of the adhesive layer at the time of manufacturing the adhesive sheet of this invention, the well-known method used for manufacture of adhesive sheets 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.

  The pressure-sensitive adhesive sheet of the present invention is usually prepared such that the thickness of the pressure-sensitive adhesive layer is preferably 3 to 100 μm, more preferably about 5 to 50 μm. It is preferable that the thickness of the pressure-sensitive adhesive layer is in the above-mentioned range because it is easy to obtain an appropriate balance between removability and adhesion (adhesion).

<Separator>
In the pressure-sensitive adhesive sheet (surface protective film) of the present invention, it is possible to bond a separator to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive surface, if necessary.

  As a material which comprises the said separator, although there exist paper and a plastic film, a plastic film is used suitably from the point which is excellent in surface smoothness. The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer, and, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer A united film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, an ethylene-vinyl acetate copolymer film and the like can be mentioned.

  The thickness of the separator is generally 5 to 200 μm, preferably about 10 to 100 μm. When it is in the above-mentioned range, it is preferable because the bonding workability to the pressure-sensitive adhesive layer and the peeling workability from the pressure-sensitive adhesive layer are excellent. The separator may be, if necessary, a release agent of silicone type, fluorine type, long chain alkyl type or fatty acid amide type, release by silica powder etc., antifouling treatment, coating type, kneading type, vapor deposition type Etc. can also be performed.

In the pressure-sensitive adhesive sheet of the present invention, the pressure-sensitive adhesive (adhesive) area of 1 cm ² of the pressure-sensitive adhesive layer was attached to a TAC polarizing plate and peeled in the shear direction at a peeling speed of 0.06 m / min after sticking for 30 minutes at 23 ° C. The shear force at that time is preferably 8.5 N / cm ² or more, more preferably 10 to 50 N / cm ² , and still more preferably 10 to 20 N / cm ² . If the shear force is within the above range, it can withstand the force in the shear direction generated when the adherend is about to curl, and the adhesive sheet does not slip or shift, and the curl of the adherend It is preferable because it can be suppressed.

<Antistatic layer (top coat layer)>
The pressure-sensitive adhesive sheet of the present invention has an antistatic layer on one side of the support film opposite to the pressure-sensitive adhesive layer, the antistatic layer comprising polyaniline sulfonic acid as a conductive polymer component, polyester resin as a binder, It is preferable to form from the antistatic agent composition which contains an isocyanate type crosslinking agent as a crosslinking agent. When the pressure-sensitive adhesive sheet has an antistatic layer (top coat layer), the antistatic property of the pressure-sensitive adhesive sheet is improved, which is a preferable embodiment.

<Conductive polymer>
The antistatic layer preferably contains polyaniline sulfonic acid as a conductive polymer component. By using the conductive polymer, the antistatic property based on the antistatic layer can be satisfied. The polyaniline sulfonic acid is "water-soluble", but can be fixed in the antistatic layer by using an isocyanate-based crosslinking agent described later, and the water resistance can be improved. By using the water-soluble conductive polymer-containing aqueous solution, an antistatic layer having excellent surface resistance over time can be obtained, which is a preferable embodiment. On the other hand, when the conductive polymer used when forming the antistatic layer is "water-dispersible", when the antistatic layer is formed using the water-dispersible conductive polymer-containing solution, aggregates are generated. It is not preferable because it tends to be easy to apply uniformly, and the surface resistance value with the passage of time tends to be extremely low.

  The content of the conductive polymer is preferably 10 to 200 parts by mass, more preferably 25 to 150 parts by mass, and further preferably 100 parts by mass of the binder contained in the antistatic layer (top coat layer). Is 40 to 120 parts by mass. If the content of the conductive polymer is too small, the antistatic effect may be reduced. If the content of the conductive polymer is too large, the adhesion of the antistatic layer to the support film may be reduced, or the transparency may be increased. It is not preferable because it may decrease.

The polyaniline sulfonic 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 antistatic layer, a method of applying and drying (or curing) a coating material (antistatic agent composition) for forming the antistatic layer on the first surface of the support film can be adopted, and preparation of the coating material The conductive polymer component to be used preferably contains polyaniline sulfonic acid, a polyester resin as a binder, and an isocyanate-based crosslinking agent as a crosslinking agent, and the essential component is dissolved in water (conductive polymer aqueous solution Or simply referred to as an aqueous solution) can be preferably used. Such a conductive polymer aqueous solution is prepared, for example, by dissolving a conductive polymer having a hydrophilic functional group (which can be synthesized by a technique such as copolymerizing a monomer having a hydrophilic functional group in the molecule) in water. can do. The hydrophilic functional group, a sulfo group, an amino group, an amide group, an imino group, a hydroxyl group, a mercapto group, a hydrazino group, a carboxyl group, quaternary ammonium groups, sulfate ester group (-O-SO 3 _H), phosphorus An acid ester group (for example, -O-PO (OH) ₂ ) etc. are illustrated. Such hydrophilic functional groups may form a salt.

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

  The antistatic layer disclosed herein contains polyaniline sulfonic acid (polyaniline type) as an essential component as the conductive polymer component, but, for example, one or more other antistatic components (conductive polymer (conductive polymer) Other organic conductive materials, inorganic conductive materials, antistatic agents, etc.) may be included together. In a preferred embodiment, the antistatic layer contains substantially no antistatic component other than the conductive polymer, that is, the antistatic component contained in the antistatic layer is substantially only the conductive polymer. The aspect which consists of may be implemented more preferably.

  As the organic conductive material, cationic antistatic agents having cationic functional groups such as quaternary ammonium salts, pyridinium salts, primary amino groups, secondary amino groups, tertiary amino groups, etc .; sulfonates and sulfates Anionic antistatic agent having an anionic functional group such as salt, phosphonic acid salt, phosphoric acid ester salt, etc .; alkylbetaine and its derivative, imidazoline and its derivative, zwitterionic antistatic agent such as alanine and its derivative; amino alcohol And nonionic antistatic agents such as glycerol and derivatives thereof, polyethylene glycol and derivatives thereof, and the like; monomers having the cationic, anionic or amphoteric ion conductive group (for example, quaternary ammonium base) Or an ion conductive polymer obtained by copolymerization; poly Include; thiophene, polyaniline, polypyrrole, polyethylene imine, a conductive polymer such as an allylamine polymer. One of such antistatic agents may be used alone, or two or more thereof may be used in combination.

  Examples of the inorganic conductive material include 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 thereof include copper iodide, ITO (indium oxide / tin oxide), ATO (antimony oxide / tin oxide) and the like. As such inorganic conductive substances, one type may be used alone, or two or more types may be used in combination.

  Examples of the antistatic agent include a cationic antistatic agent, an anionic antistatic agent, a zwitterionic antistatic agent, a nonionic antistatic agent, and a single ion conductive group having the cationic type, anionic type, and zwitterionic type. And ion conductive polymers obtained by polymerizing or copolymerizing the monomers, and the like.

<Binder>
The antistatic layer preferably contains a polyester resin as a binder. It is preferable that the said polyester resin is a resin material which contains polyester as a main component (Typically, it is a component which occupies more than 50 mass%, Preferably 75 mass% or more, for example, 90 mass% or more). The polyester is typically a polyvalent carboxylic acid (typically a dicarboxylic acid) having two or more carboxyl groups in one molecule and a derivative thereof (an anhydride, an esterified product of the polyvalent carboxylic acid, a halogen) Selected from compounds (polyvalent carboxylic acid components) selected from organic compounds and the like, and polyhydric alcohols (typically diols) having two or more hydroxyl groups in one molecule It is preferable to have a structure in which one or more compounds (polyhydric alcohol components) are condensed.

  Examples of compounds that can be adopted as the polyvalent carboxylic acid component include oxalic acid, malonic acid, difluoromalonic acid, alkyl malonic acid, succinic acid, tetrafluorosuccinic acid, alkyl succinic acid, (±) -malic acid, meso -Tartaric acid, itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylene dicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methyl glutaric acid, glutaconic acid, adipic acid, dithioadipic acid, methyl adipic acid, dimethyl Adipic acid, tetramethyl adipic acid, methylene adipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,3,6,6-tetramethylsuberic acid, azelaic acid, sebacic acid, perfluoro Sebacic acid, brassic acid, dodecyl dical Aliphatic dicarboxylic acids, such as tridecyldicarboxylic acid and tetradecyldicarboxylic acid; cycloalkyldicarboxylic acids (eg, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid), 1,4- (2- (dicarboxylic acid) Norbornene) dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid (hymic acid), adamantanedicarboxylic acid, alicyclic dicarboxylic acids such as spiroheptanedicarboxylic acid; phthalic acid, isophthalic acid, dithioisophthalic acid, methylisophthalic acid, Dimethyl isophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methylterephthalic acid, dimethylterephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalene dicarboxylic acid, oxofluorinated carboxylic acid, anthracene dicarboxylic acid Bonic acid, biphenyl dicarboxylic acid, biphenylene dicarboxylic acid, dimethyl biphenylene dicarboxylic acid, 4,4 ′ ′-p-telephenylene dicarboxylic acid, 4,4 ′ ′-p-quarrel phenyl dicarboxylic acid, bibenzyl dicarboxylic acid, azobenzene dicarboxylic acid, Homophthalic acid, phenylenediacetic acid, phenylenedipropionic acid, naphthalenedicarboxylic acid, naphthalenedipropionic acid, biphenyldiacetic acid, biphenyldipropionic acid, 3,3 '-[4,4'-(methylenedi-p-biphenylene) dipropionate Aromatic dicarboxylic acids such as acid, 4,4'-bibenzyl diacetic acid, 3,3 '(4,4'-bibenzyl) dipropionic acid, oxydi-p-phenylene diacetic acid, etc .; any of the polyvalent carboxylic acids mentioned above Acid anhydrides; esters of any of the polyvalent carboxylic acids mentioned above (E.g. alkyl esters). It may be a monoester, a diester or the like. And the like; acid halides (eg, dicarboxylic acid chlorides) corresponding to any of the polyvalent carboxylic acids described above; and the like.

  Preferable examples of the compound which 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 acid anhydrides thereof; 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 the compound which can be adopted as the polyhydric alcohol component include ethylene glycol, propylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 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, bisphenol A Can be mentioned. Other examples include alkylene oxide adducts of these compounds (e.g., 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). It may be about ^{4 to} 6 × 10 ⁴ ). Moreover, the glass transition temperature (Tg) of the said polyester resin may be 0-120 degreeC (preferably 10-80 degreeC), for example.

  As the polyester resin, a commercially available trade name "Vyronal MD-1480" manufactured by Toyobo Co., Ltd. can be used.

  The antistatic layer (top coat layer) is a resin other than a polyester resin as a binder within a range that the performance (for example, performance such as antistatic property) of the pressure-sensitive adhesive sheet (surface protective film) disclosed herein is not significantly impaired. (For example, one or more resins selected from acrylic resin, acrylic-urethane resin, acrylic-styrene resin, acrylic-silicone resin, silicone resin, polysilazane resin, polyurethane resin, fluorine resin, polyolefin resin, etc.) It can further contain. In a preferred embodiment of the technology disclosed herein, the binder of the antistatic layer consists essentially of a polyester resin. For example, the antistatic layer whose ratio of the polyester resin to a binder is 98-100 mass% is preferable. The proportion of the binder in the entire antistatic layer can be, for example, 50 to 95% by mass, and usually 60 to 90% by mass is suitable.

<Lubricant>
The antistatic layer (top coat layer) preferably uses a fatty acid amide as a lubricant. By using a fatty acid amide as a lubricant, the surface of the antistatic layer is further subjected to release treatment (for example, a treatment to apply and dry a known release treatment agent such as a silicone release agent or a long chain alkyl release agent) Even in the embodiment not applied, since it is possible to obtain an antistatic layer (top coat layer) having both sufficient slipperiness and print adhesion, it can be a preferable embodiment. Thus, such an aspect that the surface of the antistatic layer is not further subjected to peeling treatment can prevent whitening due to the peeling treatment agent (for example, whitening due to storage under heating and humidifying conditions) in advance. It is preferable in point. Moreover, it is advantageous also from the point 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-oleyl palmitic acid amide, N-stearyl stearic acid Amide, N-stearyl oleic acid amide, N-oleyl stearic acid amide, N-stearyl erucic acid amide, methylol stearic acid amide, methylene bis stearic acid amide, ethylene bis capric acid amide, ethylene bis lauric acid amide, ethylene bis stearic acid Amide, ethylenebishydroxystearic acid amide, ethylenebisbehenic acid amide, hexamethylenebisstearic acid amide, hexamethylenebisbehenic acid amide, hexamethylene hydroxystearic acid De, N, N'-distearyl adipamide, N, N'-distearyl sebacic acid amide, ethylene bis oleic acid amide, ethylene bis erucic acid amide, hexamethylene bis oleic acid amide, N, N 'dioleyl Adipic acid amide, N, N'-dioleyl sebacic acid amide, m-xylylene bis-stearic acid amide, m-xylylene bis-hydroxystearic acid amide, N, N'-stearyl isophthalic acid amide and the like. One of these lubricants may be used alone, or two or more thereof may be used in combination.

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

  The technology disclosed herein can be practiced in a mode in which the antistatic layer (top coat layer) contains other lubricants in addition to the above fatty acid amide, as long as the application effect is not significantly impaired. Examples of such other lubricants include various waxes such as petroleum waxes (paraffin wax, etc.), mineral waxes (montan wax, etc.), higher fatty acids (cerotic acid, etc.), neutral fats (palmitic acid triglyceride, etc.) Be Alternatively, in addition to the above-mentioned wax, a general silicone-based lubricant, a fluorine-based lubricant or the like may be additionally contained. The art disclosed herein can be preferably practiced in a mode substantially free of such silicone lubricants, fluorine lubricants and the like. However, the content of the silicone compound used for purposes other than the lubricant (for example, as an antifoaming agent for a coating material for forming an antistatic layer described later), as long as the application effect of the technology disclosed herein is not significantly impaired. Does not exclude

<Crosslinking agent>
It is preferable that the said antistatic layer contains an isocyanate type crosslinking agent as a crosslinking agent. By using the above-mentioned isocyanate crosslinking agent, it is possible to fix water-soluble polyaniline sulfonic acid, which is an essential component when forming the antistatic layer, in the binder, to be excellent in water resistance, and further to improve print adhesion etc. The effect can be realized.

  As the isocyanate-based crosslinking agent, it is a preferred embodiment to use a blocked isocyanate-based crosslinking agent which is stable even in an aqueous solution. Specific examples of the blocked isocyanate-based crosslinking agent include isocyanate-based crosslinking agents that can be used in the preparation of a general pressure-sensitive adhesive layer and antistatic layer (top coat layer) (for example, used in the above-mentioned pressure-sensitive adhesive layer Isocyanate compounds (isocyanate crosslinking agents), alcohols, phenols, thiophenols, amines, imides, oximes, lactams, active methylene compounds, mercaptans, imines, ureas, diaryl compounds And those blocked with sodium bisulfite etc. can be used.

  The antistatic layer in the art disclosed herein may, if necessary, be an antistatic component, an antioxidant, a colorant (pigment, dye, etc.), a flowability modifier (thixotropy agent, thickener, etc.), a film formation Additives such as assistants, surfactants (defoamers etc), preservatives etc. may be included.

<Formation of antistatic layer>
The antistatic layer (top coat layer) is a liquid composition (antistatic layer) formed by dissolving essential components such as the conductive polymer component and the like and additives used as needed in an appropriate solvent (such as water) The coating material of the present invention can be suitably formed by the method including application to the support film. For example, a method may be preferably adopted in which the coating material is applied to the first surface of the support film, dried, and curing treatment (heat treatment, ultraviolet treatment, etc.) as necessary. The NV (nonvolatile content) of the coating material 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 10%). It is suitable to set it as 1 mass%). When forming a small thickness antistatic layer, it is preferable to make NV of the said coating material into 0.05-0.50 mass% (for example, 0.10-0.40 mass%), for example. By using such a low NV coating material, a more uniform antistatic layer can be formed.

  As a solvent which comprises the coating material for antistatic layer formation, what can stably melt | dissolve the formation component of antistatic layer is preferable. Such 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 such as n-hexane and cyclohexane Hydrocarbons; Aromatic hydrocarbons such as toluene, xylene and the like; Aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol, cyclohexanol and the like; alkylene glycol monoalkyl ethers (eg ethylene glycol monomethyl ether One or more selected from glycol ethers such as ethylene glycol monoethyl ether) and dialkylene glycol monoalkyl ether; and the like can be used. In a preferred embodiment, the solvent of the coating material is water or a mixed solvent containing water as a main component (for example, a mixed solvent of water and ethanol).

<Properties of Antistatic Layer>
The thickness of the antistatic layer is typically 3-500 nm, preferably 3-100 nm, more preferably 3-60 nm). When the thickness of the antistatic layer is too small, it becomes difficult to form the antistatic layer uniformly (for example, in the thickness of the antistatic layer, the variation in the thickness depending on the location becomes large), and hence the pressure-sensitive adhesive sheet (surface protection The appearance of the film may be prone to unevenness. On the other hand, if it is too thick, it may affect the properties (optical properties, dimensional stability, etc.) of the support film.

In a preferred embodiment of the pressure-sensitive adhesive sheet (surface protective film) disclosed herein, the surface resistance (Ω / □) measured on the surface of the antistatic layer is preferably less than 1.0 × 10 ¹¹ . More preferably, it is less than 5.0 × 10 ¹⁰ , and more preferably, less than 2.0 × 10 ¹⁰ . The pressure-sensitive adhesive sheet exhibiting a surface resistance value within the above range can be suitably used as a pressure-sensitive adhesive sheet used, for example, in the process of processing or transporting articles that dislike static electricity, such as liquid crystal cells and semiconductor devices. The surface resistance value can be calculated from the surface resistance value measured in an atmosphere at 23 ° C. and 50% RH using a commercially available insulation resistance measuring device.

  The pressure-sensitive adhesive sheet (surface protective film) disclosed herein has the property that the back surface (the surface of the antistatic layer) can be easily printed with an aqueous ink or an oil-based ink (for example, using an oil-based marking pen) preferable. In this adhesive sheet, the identification number etc. of the adherend to be protected is described on the front adhesive sheet in the process of processing, conveyance, etc. of the adherend (for example, optical component) performed in a state where the adhesive sheet is attached. Is suitable for display. Therefore, it is preferable that it is an adhesive sheet excellent in printability. For example, it is preferable that the solvent is alcohol-based and has high printability to oil-based inks of the type containing a pigment. Further, it is preferable that the printed ink is difficult to be removed due to rubbing and transfer (that is, excellent in print adhesion). The pressure-sensitive adhesive sheet disclosed herein preferably also has a solvent resistance that does not cause a noticeable change in appearance when the print is wiped with alcohol (eg, ethyl alcohol) when correcting or erasing the print. .

  The pressure-sensitive adhesive sheet (surface protective film) disclosed herein may be embodied in a mode including other layers in addition to the support film (base material), the pressure-sensitive adhesive layer, and the antistatic layer. Examples of the arrangement of the “other layer” include the first surface (rear surface) of the support film and the antistatic layer, the second surface (front surface) of the support film and the pressure-sensitive adhesive layer, and the like. The layer disposed between the back of the support film and the antistatic layer can be, for example, a layer containing an antistatic component (the above-mentioned antistatic layer). The layer disposed between the support film front surface and the pressure-sensitive adhesive layer may be, for example, a subbing layer (anchor layer), an antistatic layer or the like that enhances the anchoring property of the pressure-sensitive adhesive layer to the second surface. It may be a pressure-sensitive adhesive sheet having a configuration in which the antistatic layer is disposed on the front surface of the support film, the anchor layer is disposed on the antistatic layer, and the pressure-sensitive adhesive layer is disposed thereon.

  It is preferable that the optical member of this invention is protected by the said adhesive sheet. Since the pressure-sensitive adhesive sheet is excellent in shear force, curling of the adherend (optical member) to which the pressure-sensitive adhesive sheet is bonded can be suppressed, and since it is excellent in handleability, it becomes useful.

  Hereinafter, although the example etc. which show the composition and effect of the present invention concretely are described, the present invention is not limited to these. In addition, about the compounding content in an Example etc., and characteristic evaluation, it measured as follows. Table 1 shows the physical property values of the (meth) acrylic polymer used for the pressure-sensitive adhesive composition and the mixing ratio of the pressure-sensitive adhesive composition, and Table 2 shows the mixing contents of the antistatic layer, etc. In, the evaluation result of the characteristic in an adhesive sheet was shown.

<Evaluation>
Specific measurement and evaluation methods are described below.

<Measurement of Weight Average Molecular Weight (Mw) and Number Average Molecular Weight (Mn)>
The weight average molecular weight (Mw) and number average molecular weight (Mn) of the (meth) acrylic polymer and the like used in the present invention were measured using a GPC apparatus (HLC-8220 GPC) 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; TSKguardcolumn SuperHZ-H (one) + TSKgel SuperHZM-H (two)
Reference column; TSKgel SuperH-RC (one)
Detector: Differential Refractometer (RI)
In addition, the weight average molecular weight (Mw) and the number average molecular weight (Mn) were calculated | required by the polystyrene conversion value.

<Theoretical value of glass transition temperature (Tg)>
The glass transition temperature Tg (° C.) was determined by the following equation 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 mass fraction of each monomer, Tgn (° C.) is the glass transition temperature of the homopolymer of each monomer, n is the type of each monomer Represents ]
Literature value:
2-ethylhexyl acrylate (2EHA): -70 ° C
n-Butyl acrylate (BA): -55 ° C
Acrylic acid (AA): 106 ° C
2-hydroxyethyl acrylate (HEA): -15 ° C
4-hydroxybutyl acrylate (HBA): -32 ° C

  As reference values, we referred to “Synthesis and design of acrylic resin and development of new applications” (published by the Central Business Development Center Publishing Department) and “Polymer Handbook” (John Wiley & Sons).

<Measurement of shear force>
The adhesive sheet is cut to a size of 10 mm in width and 100 mm in length, and after peeling off the separator, a TAC polarizing plate (Nitto Denko Corporation) so that the adhesive (adhesion) area of the adhesive layer of the adhesive sheet is 1 cm ² Made, SEG1423DU polarizing plate, width: 25 mm, length: 100 mm), let stand for 30 minutes at room temperature (23 ° C. × 50% RH), then pull in the shear direction at a peeling speed of 0.06 m / min. The maximum load (N / cm ² ) at that time was taken as the shear force.

The shear force is preferably 8.5 N / cm ² or more, more preferably 10 to 50 N / cm ² , and still more preferably 10 to 20 N / cm ² . If the shear force is within the above range, it can withstand the force in the shear direction generated when the adherend is about to curl, and the adhesive sheet does not slip or shift, and the curl of the adherend It is preferable because it can be suppressed.

<Measurement of surface resistance>
The measurement was performed according to JIS-K-6911 using a resistivity meter (Hiresta UP MCP-HT450 type, manufactured by Mitsubishi Chemical Analytic Co., Ltd.) under an atmosphere of temperature 23 ° C. and humidity 50% RH.

The surface resistance value (Ω / □) of the surface of the antistatic layer in the present invention is the initial stage (before the treatment with time), and the room temperature (23 ° C. × 50% RH) × one week (7 days) When both are treated, both are preferably less than 1.0 × 10 ¹¹ , more preferably less than 5.0 × 10 ¹⁰ , and still more preferably less than 2.0 × 10 ¹⁰ . A pressure-sensitive adhesive sheet (surface protective film) exhibiting a surface resistance value within the above range is suitably used, for example, as a pressure-sensitive adhesive sheet used in the process of processing or transporting articles which dislike static electricity such as liquid crystal cells and semiconductor devices. obtain.

<Measurement of peeling voltage>
The adhesive sheet 2 is cut to a size of 70 mm in width and 130 mm in length, and after peeling off the separator, TAC attached to an acrylic plate 4 (thickness: 2 mm, width: 70 mm, length: 100 mm) which has been diselectrified in advance. A polarizing plate 3 (manufactured by Nitto Denko Corporation, SEG 1423 DU polarizing plate, width: 70 mm, length: 100 mm) was pressure-bonded to the surface (TAC surface) with a hand roller such that one end protrudes 30 mm.

  After standing at 23 ° C. × 50% RH for 1 day, the sample was set at a predetermined position as shown in FIG. One end of the 30 mm portion was fixed to an automatic winder, and peeled off so that the peeling angle was 150 ° and the peeling speed was 30 m / min (high speed peeling). The potential of the polarizing plate surface generated at this time (Peeling voltage: absolute value, kV) was measured with a potential measuring instrument 1 (KSD-0103, manufactured by Kasuga Denki Co., Ltd.) fixed at the center of the polarizing plate. The measurement was performed under the environment of 23 ° C. × 50% RH.

  With a peeling angle of 150 ° and a peeling speed of 30 m / min after sticking (leaving) the adhesive surface of the adhesive layer used for the adhesive sheet on a TAC surface (polarizer surface) at 23 ° C × 50% RH for 1 day 1.0 kV or less is preferable, 0.8 kV or less is more preferable, and, as for the electric potential (peeling voltage: kV, absolute value) of the polarizing plate surface which generate | occur | produces when it peels (high-speed peeling), 0.6 kV or less is more preferable. If the peeling voltage exceeds 1.0 kV, for example, the liquid crystal driver may be damaged, which is not preferable.

<Evaluation of printability (print adhesion)>
After printing is performed on the surface of the antistatic layer using a Shachihata X stamper under a measurement environment of 23 ° C. × 50% RH, paste Sellotape (registered trademark) manufactured by Nichiban from the top of the printing, Subsequently, it peels on the conditions of 30 m / min of peeling speeds, and 180 degrees of peeling angles. Thereafter, the surface after peeling was visually observed, and when 50% or more of the printing area was peeled off, x (poor printability), and when 50% or more of the printing area remained unpeeled, ○ (good printability) It evaluated as).

<Preparation method>
Below, the synthesis | combining method of a specific (meth) acrylic-type polymer, the preparation methods, such as an adhesive composition, were described.

Preparation of Pressure-Sensitive Adhesive Composition 1
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 95 parts by mass of 2-ethylhexyl acrylate (2EHA), 4.99 parts by mass of 2-hydroxyethyl acrylate (HEA), acrylic acid (AA ) 0.01 parts by mass, 0.2 parts by mass of 2,2'-azobisisobutyro nitrile as a polymerization initiator, 150 parts by mass of ethyl acetate are charged, nitrogen gas is introduced while gently stirring, and The liquid temperature was kept at around 65 ° C. and polymerization reaction was carried out for 6 hours to prepare a (meth) acrylic polymer solution (40% by mass). The weight average molecular weight (Mw) of the (meth) acrylic polymer was 520,000, and the glass transition temperature (Tg) was -68 ° C.

  The above (meth) acrylic polymer solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and 500 parts by mass of this solution (100 parts by mass of solid content) is hexameric which is an aliphatic isocyanate compound as a crosslinking agent. 2.5 parts by mass (solid content 2.5 parts by mass) of isocyanurate of methylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX), 3 parts by mass of dibutyltin dilaurate (1 mass% ethyl acetate solution) as a crosslinking catalyst The solid content (0.03 parts by mass) was added and mixed and stirred to prepare a pressure-sensitive adhesive composition 1 (solution).

Preparation of Aqueous Solution for Antistatic Layer (Backside Treatment Agent A)
Polyester resin Vyronal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline sulfonic acid (aquapass, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.) as a conductive polymer, hexamethylene blocked with diisopropylamine as a crosslinking agent Diisocyanate isocyanurate, oleic acid amide as a lubricant, water / ethanol (1/3) mixed solvent, 100 parts by mass of solid content of binder, 75 parts of solid content of conductive polymer, solid content of crosslinking agent 10 parts by mass in amount and 30 parts by mass in solid content of the lubricant were added and thoroughly mixed for about 20 minutes with stirring. Thus, an aqueous solution for antistatic layer of about 0.4% by mass of NV was prepared.

Preparation of Aqueous Solution for Antistatic Layer (Backside Treatment Agent B)
Polyester resin Vyronal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyaniline sulfonic acid (aquapass, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co., Ltd.) as a conductive polymer, hexamethylene blocked with diisopropylamine as a crosslinking agent 100 parts by mass of solid content of binder, 75 parts of solid content of conductive polymer, 10 parts of solid content of cross-linking agent in a mixed solvent of isocyanurate of diisocyanate and water / ethanol (1/3) The mixture was added and stirred for about 20 minutes to mix well. Thus, an aqueous solution for antistatic layer of about 0.4% by mass of NV was prepared.

<Support film 1>
A transparent polyethylene terephthalate (PET) film (polyester film) having a thickness of 38 μm, a width of 30 cm and a length of 40 cm was used as a support film 1.

<Preparation of Support Film 2 with Antistatic Layer>
The antistatic layer (polyester film) is a transparent polyethylene terephthalate (PET) film (polyester film) having a thickness of 38 μm, a width of 30 cm, and a length of 40 cm in which one surface (first surface) of the support film 1 is corona treated. An aqueous solution of any of the back surface treating agents A or B) was applied so as to have a thickness of 30 nm after drying. The coated product was heated at 130 ° C. for 1 minute to be dried, to prepare a support film 2 with an antistatic layer having an antistatic layer on the first surface of the PET film.

Example 1
<Production of adhesive sheet>
The pressure-sensitive adhesive composition 1 (solution) was applied to one surface of the support film 1 and heated at 130 ° C. for 1 minute to form a pressure-sensitive adhesive layer with a thickness of 15 μm. Then, a silicone-treated surface of a polyethylene terephthalate film (thickness 25 μm), which is a separator subjected to silicone treatment on one side, was attached to the surface of the pressure-sensitive adhesive layer to prepare a pressure-sensitive adhesive sheet (surface protective film).

Examples 2 to 7 and Comparative Examples 1 to 2
A pressure-sensitive adhesive composition and a pressure-sensitive adhesive sheet were produced in the same manner as in Example 1 based on the compounding ratios in Table 1 and Table 2. In addition, the compounding quantity in Table 1 showed solid content. In Examples 3 and 4, the support film 2 with an antistatic layer was used in place of the support film 1 used in Example 1.

  According to the above evaluation method, the shear force and peeling charge voltage of the produced adhesive sheet, and in the case of the antistatic layer, the presence or absence of aggregates in the solution at the time of producing the antistatic layer, initial stage (before time treatment), and time The surface resistance and the print adhesion were evaluated, and the evaluation results are shown in Table 2 and Table 3.

The abbreviations in Tables 1 and 2 will be described below.
2EHA: 2-ethylhexyl acrylate BA: n-butyl acrylate AA: acrylic acid (carboxyl group-containing (meth) acrylic monomer)
HEA: 2-hydroxyethyl acrylate (hydroxyl-containing (meth) acrylic monomer)
HBA: 4-hydroxybutyl acrylate (hydroxyl-containing (meth) acrylic monomer)
C / HX: Nippon Polyurethane Co., Ltd., trade name "Corronate HX", aliphatic isocyanate compound, isocyanurate of hexamethylene diisocyanate (crosslinking agent)
HDPTFI: 1-hexadecyl pyridinium bis (trifluoromethanesulfonyl) imide (melting point: 34 ° C.) (onium salt, carbon number of alkyl group of onium cation constituting onium salt: 16)
HDMI TFI: 1-hexadecyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide (melting point: 42 ° C.) (onium salt, carbon number of alkyl group of onium cation constituting onium salt: 16)
MTOATF: methyltrioctylammonium trifluoromethanesulfonate (melting point: 55 ° C.) (onium salt, carbon number of alkyl group of onium cation constituting onium salt: 8)
HDMI HP: 1-hexadecyl-3-methylimidazolium hexafluorophosphate (melting point: 125 ° C.) (onium salt, carbon number of alkyl group of onium cation constituting onium salt: 16)
TDDAB: tetradodecyl ammonium bromide (melting point: 90 ° C.) (onium salt, carbon number of alkyl group of onium cation constituting onium salt: 12)
HMITF: 1-Hexyl-3-methylimidazolium trifluoromethanesulfonate (melting point: 23 ° C.) (onium salt, carbon number of alkyl group of onium cation constituting onium salt: 6)
AO compound: compound having an alkylene oxide group 25R-1: manufactured by ADEKA, trade name "Adecaplulonic 25R-1" (number average molecular weight 2800, ethylene oxide group content: 10% by mass)
KF 355A: Shin-Etsu Chemical Co., Ltd., trade name "KF-355A" (organopolysiloxane having an alkylene oxide group (HLB value 12))

  From the results of Table 3 above, it was confirmed that the shear force and the antistatic property were excellent in all the examples. Further, in Examples 3 and 4 having the antistatic layer, it was also confirmed that the surface resistance and the print adhesion were excellent.

  On the other hand, in the comparative example, since the onium salt not containing the onium cation having at least one alkyl group having 8 or more carbon atoms was used, the shear force became a low value, and it was confirmed to be inferior to the example. .

1 electric potential measuring instrument 2 adhesive sheet 3 polarizing plate 4 acrylic plate 5 fixing base

Claims (8)

It contains an onium salt having a melting point of 150 ° C. or less, a crosslinking agent, and a (meth) acrylic polymer having a glass transition temperature of 0 ° C. or less as a base polymer,
The onium salt is at least one selected from the group consisting of a nitrogen-containing onium salt, a sulfur-containing onium salt, and a phosphorus-containing onium salt,
The onium salt contains an onium cation having at least one alkyl group having 8 or more carbon atoms,
Furthermore, a pressure-sensitive adhesive composition comprising a compound having an alkylene oxide group having a number average molecular weight of 10,000 or less. The adhesion according to claim 1, characterized in that the carboxyl group-containing (meth) acrylic monomer is contained in an amount of 0.005 to 0.3 mass% with respect to the total amount of monomer components constituting the (meth) acrylic polymer. Agent composition. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the compound having an alkylene oxide group is an organopolysiloxane having an alkylene oxide group. The (meth) acrylic polymer having a glass transition temperature of 0 ° C. or less is a (meth) acrylic polymer having a hydroxyl group and a carboxyl group. Adhesive composition. It is an adhesive sheet which has an adhesive layer formed from an adhesive composition according to any one of claims 1 to 4 on one side or both sides of a support film,
The adhesive force of 1 cm ² of the adhesive layer is attached to a TAC polarizing plate, and the shear force is 8.5 N / cm ² when peeled in the shear direction at a peeling rate of 0.06 m / min after application at 23 ° C. for 30 minutes. The adhesive sheet characterized by the above. It has an antistatic layer on one side of the support film opposite to the pressure-sensitive adhesive layer,
6. The antistatic agent composition according to claim 5, wherein the antistatic layer is formed of an antistatic agent composition containing polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and an isocyanate-based crosslinking agent as a crosslinking agent. Adhesive sheet as described. The pressure-sensitive adhesive sheet according to claim 6, wherein the antistatic agent composition further contains a fatty acid amide as a lubricant. An optical member protected by the adhesive sheet according to any one of claims 5 to 7.