JP6419467B2 - Adhesive composition, adhesive sheet, and optical member - Google Patents

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 intended to protect the surface of optical members such as polarizing plates, wavelength plates, retardation plates, optical compensation films, reflection sheets, and brightness enhancement films used in liquid crystal displays. It is useful as a surface protective film used in the above.

  In recent years, when optical components / electronic components are transported or mounted on a printed circuit board, they are transferred in a state where individual components are packaged with a predetermined sheet or in a state where an adhesive tape is attached. Among these, surface protective films are particularly widely used in the field of optical and electronic components.

  The surface protective film is generally used for the purpose of preventing scratches and dirt generated during the processing and transportation of the adherend by attaching it to the adherend (protected body) via an adhesive applied to the support film side. (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. As for these optical members, the surface protection film is bonded together through the adhesive, and the damage | wound and dirt which arise at the time of a process and conveyance of a to-be-adhered body are prevented.

  When attached to an adherend (such as a polarizing plate) on the surface protective film, unnecessary or unintentional curling (curling is curled) on the adherend (such as a polarizing plate) to which the surface protective film is attached. For example, a flat plate-like object is generally warped to one of the surfaces, and a flat-plate object is generally warped so as to be wavy.) Adjustability has been demanded. When unnecessary curling or unintentional curling occurs, the handleability is inferior. For example, when an adherend such as a polarizing plate is attached to a liquid crystal cell, problems such as entrapment of bubbles may occur.

  In addition, when curling occurs on a flat adherend, a force accompanying the curl acts in the shear direction on the adhesive layer of the surface protective film bonded to the adherend, and this force causes the adherend to adhere. Since slippage and displacement occur gradually between the body and the pressure-sensitive adhesive layer, improvement in shearing force is required.

JP-A-9-165460

  Accordingly, an object of the present invention is to form a pressure-sensitive adhesive sheet that has excellent shearing force and can suppress curling of the adherend when bonded to the adherend in order to eliminate the problems in the conventional pressure-sensitive adhesive sheet. It is in providing the optical member formed by sticking the adhesive composition which can be used, the said adhesive sheet, and the said adhesive sheet for surface protection uses.

  That is, the pressure-sensitive adhesive composition of the present invention contains 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 a sulfur-containing onium salt and a phosphorus-containing onium salt, wherein 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 lower 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 from the pressure-sensitive adhesive composition on one side or both sides of a support film, and a pressure-sensitive adhesive area of 1 cm ² of the pressure-sensitive adhesive layer is attached to a TAC polarizing plate. In addition, the shearing force when peeling in the shearing direction at a peeling speed of 0.06 m / min after pasting at 23 ° C. for 30 minutes is preferably 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, and the antistatic layer comprises polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and It is preferably formed from an antistatic composition containing an isocyanate-based crosslinking agent as a crosslinking agent.

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

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

  Since the pressure-sensitive adhesive sheet formed from the pressure-sensitive adhesive composition of the present invention has excellent shearing force, it suppresses unnecessary curling and unintended curling on the adherend when bonded to the adherend. Can and is useful.

Schematic diagram of potential measurement unit

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

<Overall structure of adhesive sheet (surface protective film)>
The pressure-sensitive adhesive sheet (surface protective film) of the present invention is generally in the form of a pressure-sensitive adhesive sheet, pressure-sensitive adhesive tape, pressure-sensitive adhesive label, pressure-sensitive adhesive film, etc., and particularly optical components (for example, liquid crystals such as polarizing plates and wave plates). It is suitable as a surface protective film for protecting the surface of the optical component during processing or transport of the 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, for example, a pressure-sensitive adhesive formed in a regular or random pattern such as a spot or stripe. It may be an agent layer. Further, the pressure-sensitive adhesive sheet disclosed herein may be in the form of a roll or a single sheet.

  Typical examples of the pressure-sensitive adhesive sheet (surface protective film) disclosed herein include those having a pressure-sensitive adhesive layer on one side or both sides of the support film (base material), or antistatic provided on one side of the support film. And a layer provided with 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 attaching this pressure-sensitive adhesive layer to an adherend (the surface of an optical component such as a polarizing plate). The pressure-sensitive adhesive sheet before use (that is, before sticking to the adherend) is protected by a release liner whose surface (sticking surface to the adherend) is at least the pressure-sensitive adhesive layer side. The form may be sufficient. Or the form by which the adhesive layer contact | abutted to the back surface (surface of the antistatic layer) of the support film and the surface was protected by winding an adhesive sheet in roll shape may be sufficient.

<Adhesive composition>
The pressure-sensitive adhesive composition of the present invention comprises an onium salt having a melting point of 150 ° C. or lower and a polymer having a glass transition temperature of 0 ° C. or lower as a base polymer, and the onium salt is a nitrogen-containing onium salt or sulfur-containing polymer. It is at least one selected from the group consisting of an onium salt and a phosphorus-containing onium salt, wherein 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, the onium salt having a melting point of 150 ° C. or lower, and the base polymer containing the polymer having a glass transition temperature (Tg) of 0 ° C. or lower and capable of expressing adhesiveness, Can be used without any particular restrictions. For example, an acrylic adhesive, a urethane adhesive, a polyester adhesive, a synthetic rubber adhesive, a natural rubber adhesive, a silicone adhesive, and the like can be used. Among them, the acrylic pressure-sensitive adhesive is a preferable embodiment particularly in that the pressure-sensitive adhesive property can be easily controlled.

  In the present invention, the polymer having a glass transition temperature (Tg) of 0 ° C. or lower is preferably a (meth) acrylic polymer, and is a (meth) acrylic polymer having a hydroxyl group and a carboxyl group. More preferable. By using a polymer having a glass transition temperature (Tg) of 0 ° C. or lower, it is possible to design a pressure-sensitive adhesive having excellent adhesive properties, and by using the (meth) acrylic polymer, control of the adhesive properties is possible. Is easily possible, and this is a preferred embodiment. Moreover, 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 shearing force. Or an increase in adhesive strength over time can be prevented. In particular, by using the (meth) acrylic polymer having a hydroxyl group and a carboxyl group, the shearing force of the pressure-sensitive adhesive (layer) is improved, and by bonding the pressure-sensitive adhesive to the adherend, Curling based on the adherend can be suppressed, and the occurrence of slipping and displacement between the adhesive and the adherend (interface) can be suppressed, which is preferable.

  In the present invention, the base polymer contains a polymer having a glass transition temperature (Tg) of 0 ° C. or lower. In 100% by mass of the base polymer, a polymer having a glass transition temperature (Tg) of 0 ° C. or lower is used. A more preferable embodiment is 100% by mass. The (meth) acrylic polymer in the present invention refers to an acrylic polymer and / or a methacrylic polymer, and the (meth) acrylate refers to acrylate and / or 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. By using the hydroxyl group-containing (meth) acrylic monomer, it becomes easier to control the crosslinking of the pressure-sensitive adhesive composition, and as a result, the improvement in wettability by flow and the balance between the cohesive force and shearing force of the pressure-sensitive adhesive (layer). It becomes easy to control. Further, when an antistatic agent is added to the pressure-sensitive adhesive, unlike a carboxyl group or a sulfonate group that can generally act as a crosslinking site, a hydroxyl group is an appropriate amount of an onium salt having a melting point of 150 ° C. or less, which is an antistatic agent. Since it has interaction, it can act suitably also in terms of antistatic properties.

  In this invention, it is preferable to contain 0.5-15 mass% of hydroxyl group containing (meth) acrylic monomers with respect to the monomer component whole quantity which comprises the said (meth) acrylic-type polymer, More preferably, it is 0.8. It is 6-7 mass%, More preferably, it is 0.7-4.99 mass%, Most preferably, it is 1.0-3.9 mass%. Within the above range, the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force and shear force of the pressure-sensitive adhesive (layer) can be easily controlled, which is preferable. Further, in order to develop good charging characteristics with a smaller blend amount of the onium salt, it is effective that the blend amount of the hydroxyl group-containing (meth) acrylic monomer is small.

  Examples of the hydroxyl group-containing (meth) acrylic monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) acrylate. 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide and the like. The hydroxyl group-containing (meth) acrylic monomer may be used alone, or two or more may be used as monomer components.

  The (meth) acrylic polymer preferably contains the carboxyl group-containing (meth) acrylic monomer as a monomer component. By using the carboxyl group-containing (meth) acrylic monomer, the pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer) can suppress an increase in the adhesive strength over time, re-peelability, adhesive strength increase prevention, and workability In addition, the cohesive force of the pressure-sensitive adhesive layer and the shearing force are also excellent, which is preferable.

  In this invention, it is preferable to contain a carboxyl group-containing (meth) acrylic-type monomer 0.005-0.5 mass% with respect to the monomer component whole quantity which comprises the said (meth) acrylic-type polymer, More preferably It is 0.006-0.4 mass%, More preferably, it is 0.008-0.3 mass%, Most preferably, it is 0.01-0.2 mass%. Within the above range, an increase in adhesive force over time can be suppressed, and the removability, the adhesive force increase preventing property, and the workability are excellent. In addition to the cohesive force of the pressure-sensitive adhesive layer, it is excellent in shearing force and is preferable. When a large number of acid functional groups such as carboxyl groups having a large polar action are present, an onium salt having a melting point of 150 ° C. or lower that can be used as an antistatic agent is blended with the acid functional groups such as carboxyl groups and the onium The interaction of salt or the like is not preferable because ionic conduction is hindered, the conduction efficiency is lowered, and sufficient antistatic properties may not be obtained.

  Examples of the carboxyl group-containing (meth) acrylic monomer include (meth) acrylic acid, carboxylethyl (meth) acrylate, carboxylpentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2 -(Meth) acryloyloxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl maleic acid, carboxy Examples thereof include polycaprolactone mono (meth) acrylate and 2- (meth) acryloyloxyethyl tetrahydrophthalic acid. The carboxyl group-containing (meth) acrylic monomer may be used alone, or two or more kinds may be used as the monomer component.

  Moreover, in this invention, it is preferable that the said (meth) acrylic-type polymer uses the (meth) acrylic-type monomer which has a C1-C14 alkyl group as a monomer component, More preferably, it is C4-C14. (Meth) acrylic monomer having an alkyl group of The (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms may be used alone, or two or more kinds 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, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) ) Acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl ( (Meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, etc. It is done.

  Especially, when using the adhesive sheet of this invention as a surface protection 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. Suitable examples include (meth) acrylates having an alkyl group having 6 to 14 carbon atoms. By using (meth) acrylate having an alkyl group having 6 to 14 carbon atoms, it becomes easy to control the adhesive force to the adherend to be low, and the removability is excellent.

  In this invention, 50-99 mass% of (meth) acrylic-type monomers which have the said C1-C14 alkyl group are contained with respect to the monomer component whole quantity which comprises the said (meth) acrylic-type polymer. More preferably, it is 60-98.8 mass%, More preferably, it is 70-98.6 mass%, Most preferably, it is 80-98.4 mass%. By being in the said range, an adhesive composition has moderate wettability and is excellent also in the cohesion force of an adhesive (layer), and is preferable.

  In addition, as another polymerizable monomer component, the (meth) acrylic polymer is prepared so that the glass transition temperature (Tg) is 0 ° C. or lower (usually −100 ° C. or higher) because the adhesive performance is easily balanced. A polymerizable monomer for adjusting the Tg and releasability of the present invention can be used as long as the effects of the present invention are not impaired.

  Other than the hydroxyl group-containing (meth) acrylic monomer, carboxyl group-containing (meth) acrylic monomer, and (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms used in the (meth) acrylic polymer The other polymerizable monomer can be used without particular limitation as long as it does not impair the characteristics of the present invention. For example, cohesive strength / heat resistance improving components such as cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, amide group-containing monomers, imide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, vinyl ether monomers, etc. A peeling force adjusting component such as a component having a functional group that works as an adhesive (adhesive) strength improvement or a crosslinking base point, and 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, vinyl laurate, and the like.

  Examples of the aromatic vinyl monomer include styrene, chlorostyrene, chloromethyl styrene, α-methyl styrene, and other substituted styrene.

  Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, 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-methylolacrylamide, diacetone acrylamide, N-vinylacetamide, N, N′-methylenebis 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 cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and itaconimide.

  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, and allyl glycidyl ether.

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

  Examples of the alkylene oxide group-containing monomer include methoxy-polyethylene glycol (meth) acrylate types such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) acrylate, ethoxy-diethylene glycol (meth) acrylate, 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, etc. 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 Examples include acrylate type.

  In the present invention, other polymerizable monomers other than the carboxyl group-containing (meth) acrylic monomer, the hydroxyl group-containing (meth) acrylic monomer, and the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms. Is preferably 0 to 40% by mass, and more preferably 0 to 30% by mass in the total amount of monomer components (total monomer component) constituting the (meth) acrylic polymer. By using the other polymerizable monomer within the above range, a good interaction with an onium salt having a melting point of 150 ° C. or lower that can be used as an antistatic agent, and a good removability can be appropriately adjusted. .

  Further, when the nitrogen-containing monomer such as the amide group-containing monomer is used as the other polymerizable monomer as a monomer component of the (meth) acrylic polymer, it is preferably contained in an amount of 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 cohesive force of the resulting pressure-sensitive adhesive (layer) can be improved, and an excellent shearing force can be expressed. Further, curl control (curl controllability) ) It is estimated that the nature will be higher. Moreover, curl controllability at high temperatures can be improved, which is useful. Further, it is presumed that the onium salt is less likely to bleed due to coordination of onium having a melting point of 150 ° C. or less to a nitrogen atom contained in the nitrogen-containing monomer, and an excellent shearing force can be realized. In addition, when calculating | requiring lower adhesive force as an adhesive sheet, the one where content of nitrogen-containing monomer is smaller is preferable.

  The (meth) acrylic polymer preferably has a weight average molecular weight (Mw) of 100,000 to 5,000,000, more preferably 200,000 to 4,000,000, still more preferably 300,000 to 3,000,000, and most preferably 400,000 to 700,000. It is. When Mw is smaller than 100,000, there is a tendency for adhesive residue to occur due to the reduced cohesive force of the resulting pressure-sensitive adhesive layer. On the other hand, when Mw exceeds 5,000,000, the fluidity of the polymer is lowered and the wettability to the adherend (for example, a polarizing plate as an optical member) becomes insufficient, and the adherend and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet There is a tendency to cause blisters occurring between the (adhesive composition layer). In addition, Mw means what was obtained by measuring by a gel permeation chromatography method (GPC).

  Further, the polymer having a glass transition temperature (Tg) of 0 ° C. or lower (for example, the (meth) acrylic polymer) has a Tg of 0 ° C. or lower, preferably −10 ° C. or lower, more preferably −40 It is ℃ or less, more preferably -60 ℃ or less (usually -100 ℃ or more). When Tg is higher than 0 ° C., the polymer is difficult to flow. For example, the adherend (eg, a polarizing plate as an optical member) is insufficiently wetted, and the adherend and the pressure-sensitive adhesive layer (pressure-sensitive adhesive composition) Tend to cause blisters to occur between the two layers. Moreover, it becomes easy to obtain the adhesive composition which is excellent in the wettability to a to-be-adhered body, and light peelability by making Tg 0 degrees C or less. The Tg of the polymer having a glass transition temperature (Tg) of 0 ° C. or lower (for example, the (meth) acrylic polymer) can be adjusted within the above range by appropriately changing the monomer component and composition ratio to be used. .

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

  The pressure-sensitive adhesive composition of the present invention contains an onium salt having a melting point of 150 ° C. or lower, and the onium salt is at least selected from the group consisting of a nitrogen-containing onium salt, a sulfur-containing onium salt, and a phosphorus-containing onium salt. It is 1 type, The said onium salt contains the onium cation which has at least 1 C8 or more alkyl group, It is characterized by the above-mentioned. Use of an onium salt having a melting point of 150 ° C. or lower (preferably 100 ° C. or lower, more preferably 30 ° C. or higher and 60 ° C. or lower) facilitates dispersion into the base polymer, which is a preferred embodiment. Further, 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 becomes possible to express excellent charging characteristics, and When the onium salt contains an onium cation having at least one alkyl group having 8 or more carbon atoms, it is possible to achieve both shear characteristics and charging characteristics, which is preferable.

  The onium salt having a melting point of 150 ° C. or lower, 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 onium salts, nitrogen-containing onium salts include 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-methylimidazolium bi (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) imidomethyltrioctylammonium triflate, methyltri Octylammonium trifluoromethanesulfonate, tetraoctylammonium bromide, hexadecyl Such as trimethyl ammonium hexafluorophosphate and the like.

  Among the onium salts, examples of the sulfur-containing onium salt include diethyltetradecylsulfonium hexafluorophosphate.

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

  Moreover, 0.1-4.9 mass parts is preferable with respect to 100 mass parts of said base polymers, 0.2-4 mass parts is more preferable, 0.5-3 mass parts Is more preferable, and 0.7 to 1.4 parts by mass is most preferable. It is preferable for it to be in the above-mentioned range since it is easy to achieve both antistatic properties and low contamination.

  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 having an alkylene oxide group, a pressure-sensitive adhesive composition having excellent wettability to an adherend can be obtained.

  Specific examples of the compound having an alkylene oxide group include, 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 alkylphenyl allyl ether; polyoxyalkylene alkyl ether sulfate ester salt, polyoxyalkylene alkyl ether phosphate ester salt, polyoxyalkylene alkyl phenyl ether Anionic surface activity such as sulfate ester salt, polyoxyalkylene alkylphenyl ether phosphate ester salt Agents: Other cationic surfactants and amphoteric surfactants having polyalkylene oxide groups (polyalkylene oxide chains), polyether compounds having polyalkylene oxide groups (and derivatives thereof), polyalkylene oxide groups And a polyester compound having a polyalkylene oxide group (and derivatives thereof) and the like. Moreover, you may mix | blend with the said base polymer (for example, the said (meth) acrylic-type polymer) as a compound which has the said alkylene oxide group using an alkylene oxide group containing monomer. The said compound which has an alkylene oxide group may be used independently, and may be used in combination of 2 or more type.

  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. A copolymer etc. are mentioned. Examples of the derivative of the polyether compound having an alkylene oxide group include an oxypropylene group-containing compound (PPG monoalkyl ether, PEG-PPG monoalkyl ether, etc.) whose terminal is etherified, and an oxypropylene group whose terminal is acetylated Compound (terminal acetylated PPG etc.) etc. are mentioned.

  Specific examples of the acrylic compound having an alkylene oxide group include a (meth) acrylate polymer having an oxyalkylene group. As the oxyalkylene group, the added mole number of oxyalkylene units is preferably 1 to 50, more preferably 2 to 30, more preferably 2 to 20 from the viewpoint of coordination of the onium salt as an antistatic agent and the like. preferable. Moreover, the terminal of the oxyalkylene group may be a hydroxyl group, or may be substituted with an alkyl group, a phenyl group or the like.

  The (meth) acrylate polymer having an oxyalkylene group is preferably a polymer containing (meth) acrylic acid alkylene oxide as a monomer component (monomer unit). Specific examples of the (meth) acrylic acid alkylene oxide Examples thereof include ethylene glycol group-containing (meth) acrylates. For example, methoxy-polyethylene glycol (meth) acrylate types such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) acrylate, ethoxy-diethylene glycol ( Ethoxy-polyethylene glycol (meth) acrylate type such as meth) acrylate, ethoxy-triethylene glycol (meth) acrylate, butoxy-diethylene glycol (meth) acrylate Phenoxy-polyethylene glycol (meth) acrylate such as butoxy-polyethylene glycol (meth) acrylate type such as butoxy-triethylene glycol (meth) acrylate, phenoxy-diethylene glycol (meth) acrylate, phenoxy-triethylene glycol (meth) acrylate And methoxy-polypropylene glycol (meth) acrylate types such as 2-ethylhexyl-polyethylene glycol (meth) acrylate, nonylphenol-polyethylene glycol (meth) acrylate type, and methoxy-dipropylene glycol (meth) acrylate.

  Moreover, as said monomer component, other monomer components other than the said (meth) acrylic-acid alkylene oxide can be used. Specific examples of other monomer components include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, 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 , Acrylate and / or methacrylate having an alkyl group having 1 to 14 carbon atoms such as isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, and n-tetradecyl (meth) acrylate Door and the like.

  Further, 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-acryloylmorpholine, vinyl ether It is also possible to use a kind etc. suitably.

  In a preferred embodiment, the compound having an alkylene oxide group is a compound having a (poly) ethylene oxide group at least partially. By compounding 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. Thus, a low-staining adhesive composition is obtained. In particular, when a PPG-PEG-PPG block copolymer is used, a pressure-sensitive adhesive composition excellent in low contamination can be obtained. As said (poly) ethylene oxide group containing compound, it is preferable that the mass of the (poly) ethylene oxide group which occupies for the said whole compound is 5-90 mass%, More preferably, it is 5-85 mass%, More preferably, it is 5-80 % By mass, most preferably 5 to 75% by mass.

  The molecular weight of the compound having an alkylene oxide group is preferably a number average molecular weight (Mn) of 10,000 or less, more preferably 200 to 8000, still more preferably 300 to 6000, and particularly preferably 400 to 4000. If Mn is larger than 10,000, the compatibility with the base polymer (for example, the (meth) acrylic polymer) is lowered, and the pressure-sensitive adhesive layer tends to be whitened. If 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.

  Specific examples of commercially available compounds having an alkylene oxide group include, for example, Adekapluronic 17R-4, Adekapluronic 25R-1, Adekapluronic 25R-2 (above, manufactured by ADEKA), Emulgen 120 (above, And Kao).

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

  As the organopolysiloxane, a known organopolysiloxane having an alkylene oxide group can be used as appropriate. For example, as commercial products, trade names are X-22-4952, X-22-4272, X-22-6266, KF. -6004, KF-889, KF-351A, KF-352A, KF-353, KF-354L, KF-355A, 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 (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 (above, manufactured by Toray Dow Corning), IM22 (above, manufactured by Asahi Kasei Wacker), TSF-4440, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4442, TSF-4460 (manufactured by Momentive Performance Materials), BYK-333, BYK-307, BYK-377, Examples include BYK-UV3500, BYK-UV3570 (manufactured by Big Chemie Japan). These may be used singly or in combination of two or more.

  The organopolysiloxane used in the present invention preferably has an HLB (Hydrophile-Lipophile Balance) value of 1 to 16, more preferably 3 to 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 with respect to 100 parts by mass of the base polymer is preferably 0.01 to 5 parts by mass, more preferably 0.03 to 1. It is a mass part, More preferably, it is 0.05-0.5 mass part, Most preferably, it is 0.1-0.2 mass part. It is preferable for it to be in the above-mentioned range since it is easy to achieve both antistatic properties and light releasability (removability). In addition, when there is little content, the effect which prevents the bleeding of an antistatic component will decrease, and when there is much content, the contamination by the compound itself which has the said alkylene oxide group may arise easily, and it is unpreferable.

  The pressure-sensitive adhesive composition of the present invention preferably contains a crosslinking agent. In addition, in this invention, it can be set as an adhesive layer using the said adhesive composition. For example, when the pressure-sensitive adhesive contains the (meth) acrylic polymer, the structural unit, the structural ratio, the selection and addition ratio of the crosslinking agent, etc. of the (meth) acrylic polymer are appropriately adjusted for crosslinking. A pressure-sensitive adhesive sheet (pressure-sensitive adhesive layer) having better 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. In particular, the use of an isocyanate compound is a preferred embodiment. Moreover, these compounds may be used independently and may be used in mixture of 2 or more types.

  Examples of the isocyanate compound (isocyanate-based crosslinking agent) include aliphatic polyisocyanates such as trimethylene diisocyanate, butylene diisocyanate, hexamethylene diisocyanate (HDI), and dimer acid diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate. (IPDI) and other alicyclic isocyanates, 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate (XDI) and other aromatic isocyanates, and the isocyanate compounds are allophanate bonds, biuret bonds, Isocyanurate bond, uretdione bond, urea bond, carbodiimide bond, uretonimine bond, oxy Polyisocynate modified product obtained by modifying the like trione bond. For example, as commercial products, the product names Takenate 300S, Takenate 500, Takenate D165N, Takenate D178N (above, Takeda Pharmaceutical Co., Ltd.), Sumijoule T80, Sumijoule L, Death Module N3400 (above, Sumika Bayer Urethane Co., Ltd.) Millionate MR, Millionate MT, Coronate L, Coronate HL, Coronate HX (above, manufactured by Nippon Polyurethane Industry Co., Ltd.) and the like. These isocyanate compounds may be used alone, or may be used in combination of two or more, and a bifunctional isocyanate compound and a trifunctional or higher isocyanate compound may be used in combination. By using a cross-linking agent in combination, it becomes possible to achieve both tackiness and resilience resistance (adhesiveness to a curved surface), and a surface protective film with better adhesion reliability can be obtained.

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

  Examples of the melamine resin include hexamethylol melamine. Examples of the aziridine derivative include commercially available product names HDU, TAZM, TAZO (manufactured by Mutual Yakugyo Co., Ltd.) and the like.

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

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

  The pressure-sensitive adhesive composition may further contain a crosslinking catalyst in order to more effectively advance any of the crosslinking reactions described above. Examples of such crosslinking catalysts include tin 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-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 (tridecan-6,8-dionato) iron, tris (1-phenylbutane-1, -Dionato), tris (hexafluoroacetylacetonato) iron, tris (ethyl acetoacetate) iron, tris (acetoacetate-n-propyl) iron, tris (isopropyl acetoacetate) iron, tris (acetoacetate-n-butyl) Iron, tris (acetoacetate-sec-butyl) iron, tris (acetoacetate-tert-butyl) iron, tris (methyl propionylacetate) iron, tris (ethyl propionylacetate) iron, tris (propionylacetate-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, trimethoxy iron, 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. For example, the base polymer is preferably about 0.0001 to 1 part by mass with respect to 100 parts by mass of the (meth) acrylic polymer. 5 parts by mass is more preferable. Within the above range, when the pressure-sensitive adhesive layer is formed, the speed of the crosslinking reaction is high, and the pot life of the pressure-sensitive adhesive composition becomes long, which is a preferred embodiment.

  Furthermore, the pressure-sensitive adhesive composition may contain an acrylic oligomer. The acrylic oligomer preferably has a weight average molecular weight (Mw) of 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 10,000. When Mw is 30000 or more, the adhesion (adhesion) property is lowered. Moreover, since it becomes low molecular weight as Mw is less than 1000, the fall of the adhesive force of an adhesive sheet may be caused.

For the acrylic oligomer, a (meth) acrylic acid ester monomer 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, heptyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, (meth) acrylic acid Decyl, isodecyl (meth) acrylate, undecyl (meth) acrylate , (Meth) such as acrylic acid dodecyl (meth) acrylic acid alkyl ester;
(Meth) acrylic acid aryl esters such as phenyl (meth) acrylate and benzyl (meth) acrylate;
Examples thereof include (meth) acrylic acid esters obtained from terpene compound derivative alcohols.
The acrylic oligomer may be a (meth) acrylic monomer having an alicyclic structure, such as dicyclopentanyl methacrylate, dicyclopentanyl acrylate, dicyclopentanyloxyethyl 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- 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.

  Further, the pressure-sensitive adhesive composition can contain a compound that causes keto-enol tautomerism as a crosslinking retarder. For example, in a pressure-sensitive adhesive composition containing a cross-linking agent or a pressure-sensitive adhesive composition that can be used by blending a cross-linking agent, an embodiment including a compound that produces the keto-enol tautomerism can be preferably employed. Thereby, the excessive viscosity raise and gelation of an adhesive composition after a crosslinking agent mixing | blending 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 crosslinking agent, it is particularly meaningful to contain a compound that causes keto-enol tautomerism. This technique can be preferably applied when, for example, the pressure-sensitive adhesive composition is in an organic solvent solution or a solvent-free form.

  Various β-dicarbonyl compounds can be used as the compound that causes keto-enol tautomerism. Specific examples 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; acetoacetates 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 isobutylyl acetate; malonates such as methyl malonate and ethyl malonate; etc. And the like. Among these, acetylacetone and acetoacetic acid esters are preferable compounds. Such compounds that produce keto-enol tautomerism may be used alone or in combinations of two or more.

  The content of the compound causing 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. Is suitably 0.5 to 15 parts by mass (eg 1 to 10 parts by mass). If the amount of the compound is too small, it may be difficult to achieve 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 cohesive force.

  Furthermore, the pressure-sensitive adhesive composition of the present invention may contain other known additives, such as powders such as colorants and pigments, surfactants, plasticizers, tackifiers, low molecular weights, and the like. Polymers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, UV absorbers, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, metal powders, particles, foils It can be added as appropriate depending on the purpose of using the product.

  The pressure-sensitive adhesive sheet of the present invention preferably has a pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition (formed by crosslinking the pressure-sensitive adhesive composition) on one side or both sides of the support film. The crosslinking of the pressure-sensitive adhesive composition is generally performed after application of the pressure-sensitive adhesive composition, but it is also possible to transfer a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition after crosslinking to 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 is 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 or adjusting the crosslinking reaction. In addition, when a pressure-sensitive adhesive composition is applied on a support film to prepare a pressure-sensitive adhesive sheet, one or more solvents other than the polymerization solvent are newly added to the pressure-sensitive adhesive composition so that the pressure-sensitive adhesive composition can be uniformly applied on the support film. You may add to.

<Support film>
As the support film, the resin material constituting the support film can be used without any particular limitation, for example, transparency, mechanical strength, thermal stability, moisture shielding, isotropic, flexibility, It is preferable to use one having excellent characteristics such as dimensional stability. In particular, since 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 polymers such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polybutylene terephthalate; cellulose polymers such as diacetyl cellulose and triacetyl cellulose; polycarbonate polymers; A plastic film composed of a resin material having an acrylic polymer such as methyl methacrylate as a main resin component (a main component of the resin component, typically a component occupying 50% by mass or more) is used as the support film. It can be preferably used. Other examples of the resin material include styrene polymers such as polystyrene and acrylonitrile-styrene copolymers; olefin polymers such as polyethylene, polypropylene, polyolefins having a cyclic or norbornene structure, and ethylene-propylene copolymers; Examples of the resin material include vinyl chloride polymers; amide polymers such as nylon 6, nylon 6,6, and aromatic polyamide. Still other examples of the resin material include imide polymers, sulfone polymers, polyether sulfone polymers, polyether ether ketone polymers, polyphenylene sulfide polymers, vinyl alcohol polymers, vinylidene chloride polymers, vinyl butyral polymers. , Arylate polymers, polyoxymethylene polymers, epoxy polymers and the like. A support film made of a blend of two or more of the above-described polymers may be used.

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

  Various additives such as an antioxidant, an ultraviolet absorber, a plasticizer, and a colorant (pigment, dye, etc.) may be blended in the resin material constituting the support film, if necessary. For example, corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and application of a primer are applied to the first surface of the polyester film (the surface on which the antistatic layer is provided). The surface treatment may be performed. Such a surface treatment can be, for example, a treatment for enhancing the adhesion between the support film and the antistatic layer. Surface treatment in which polar groups such as hydroxyl groups are introduced on the surface of the support film can be preferably employed. Moreover, the surface treatment similar to the above may be given to the 2nd surface (surface on the side in which an adhesive layer is formed) of a support film. Such a surface treatment may be a treatment for enhancing the adhesion between the film and the pressure-sensitive adhesive layer (the anchoring property of the pressure-sensitive adhesive layer).

  In addition, the pressure-sensitive adhesive sheet of the present invention can have an antistatic layer on the support film, but when it has an antistatic function, a plastic film that has been subjected to antistatic treatment is used as the support film. It is also possible to do. Use of the support film is preferable because charging of the pressure-sensitive adhesive sheet itself when peeled can be suppressed. Further, the support film is a plastic film, and by applying an antistatic treatment to the plastic film, it is possible to reduce the charge of the pressure-sensitive adhesive sheet itself and to have an excellent antistatic ability to the adherend. In addition, there is no restriction | limiting in particular as a method to provide an antistatic function, A conventionally well-known method can be used, for example, antistatic resin which consists of an antistatic agent and a resin component, a conductive polymer, a conductive substance Examples thereof include a method of applying a conductive resin, a method of depositing or plating a conductive material, a method of kneading an antistatic agent, and the like.

  The thickness of the support film is usually 5 to 200 μm, preferably about 10 to 100 μm. When the thickness of the support film is within the above range, it is preferable because the workability for bonding to the adherend and the workability for peeling 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 include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, extrusion coating using a die coater, and the like.

  The pressure-sensitive adhesive sheet of the present invention is usually prepared so that the thickness of the pressure-sensitive adhesive layer is preferably 3 to 100 μm, more preferably about 5 to 50 μm. It is preferable for the thickness of the pressure-sensitive adhesive layer to be within the above-mentioned range, since it is easy to obtain a suitable balance between removability and adhesion (adhesion).

<Separator>
In the pressure-sensitive adhesive sheet (surface protective film) of the present invention, a separator can be bonded to the surface of the pressure-sensitive adhesive layer for the purpose of protecting the pressure-sensitive adhesive surface as necessary.

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

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

The pressure-sensitive adhesive sheet of the present invention was bonded to a TAC polarizing plate with a pressure-sensitive adhesive (adhesion) area of 1 cm ² of the pressure-sensitive adhesive layer, and peeled in the shear direction at a peeling rate of 0.06 m / min after being stuck at 23 ° C. for 30 minutes. The shearing 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 shearing force is within the above range, it can withstand the force in the shearing direction that occurs when the adherend tries to curl, and the adhesive sheet does not slip or slip, and the adherend is curled. Since it can suppress, it is preferable.

<Antistatic layer (topcoat 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, and the antistatic layer comprises polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, and It is preferably formed from an antistatic composition containing an isocyanate-based crosslinking agent as a crosslinking agent. When the pressure-sensitive adhesive sheet has an antistatic layer (topcoat layer), the antistatic property of the pressure-sensitive adhesive sheet is improved, which is a preferred embodiment.

<Conductive polymer>
The antistatic layer preferably contains polyaniline sulfonic acid as a conductive polymer component. By using the conductive polymer, antistatic properties 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 water resistance can be improved. By using the water-soluble conductive polymer-containing aqueous solution, an antistatic layer having an excellent surface resistance value with time can be obtained, which is a preferred embodiment. On the other hand, when the conductive polymer used in forming the antistatic layer is “water-dispersible”, aggregates are generated when the antistatic layer is formed using the water-dispersible conductive polymer-containing solution. This is not preferable because it tends to be easy and cannot be applied uniformly, and the surface resistance value with time tends to be extremely inferior.

  The content of the conductive polymer is preferably 10 to 200 parts by weight, more preferably 25 to 150 parts by weight, further preferably 100 parts by weight of the binder contained in the antistatic layer (topcoat layer). Is 40-120 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 decreased. There is a risk of lowering, which is not preferable.

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. In addition, the weight average molecular weight of these conductive polymers is usually preferably 1 × 10 ³ or more, and 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 an antistatic layer on the first surface of the support film can be adopted. The conductive polymer component used in the invention preferably contains polyaniline sulfonic acid, a polyester resin as the binder, and an isocyanate-based cross-linking agent as the cross-linking agent, and the essential component dissolved in water (conductive polymer aqueous solution) Or simply referred to as an aqueous solution). Such an aqueous conductive polymer solution is prepared by, for example, dissolving a conductive polymer having a hydrophilic functional group (which can be synthesized by a method such as copolymerizing a monomer having a hydrophilic functional group in the molecule) in water. can do. Examples of the hydrophilic functional group include a sulfo group, amino group, amide group, imino group, hydroxyl group, mercapto group, hydrazino group, carboxyl group, quaternary ammonium group, sulfate group (—O—SO ₃ H), phosphorus An acid ester group (for example, —O—PO (OH) ₂ ) and the like are exemplified. Such hydrophilic functional groups may form a salt.

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

  The antistatic layer disclosed herein contains polyaniline sulfonic acid (polyaniline type) as an essential component as the conductive polymer component. For example, one or more other antistatic components (conductive polymer) Organic conductive materials other than the above, 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 a conductive polymer. The embodiment consisting of can be implemented more preferably.

  Examples of the organic conductive substance include cation type antistatic agents having a cationic functional group such as a quaternary ammonium salt, a pyridinium salt, a primary amino group, a secondary amino group, and a tertiary amino group; sulfonates and sulfates Anionic antistatic agents having an anionic functional group such as salts, phosphonates, phosphate esters; amphoteric ionic antistatic agents such as alkylbetaines and their derivatives, imidazolines and their derivatives, alanine and their derivatives; amino alcohols Nonionic antistatic agents such as glycerin and derivatives thereof, glycerin and derivatives thereof, polyethylene glycol and derivatives thereof; polymerization of monomers having the cation type, anion type or zwitterion type ion conductive groups (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. Such an antistatic agent may be used individually by 1 type, and may be used in combination of 2 or more type.

  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. Such inorganic conductive materials may be used alone or in combination of two or more.

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

<Binder>
The antistatic layer preferably contains a polyester resin as a binder. The polyester resin is preferably a resin material containing polyester as a main component (typically exceeding 50% by mass, preferably 75% by mass or more, for example, 90% by mass or more). The polyester typically includes polyvalent carboxylic acids (typically dicarboxylic acids) having two or more carboxyl groups in one molecule and derivatives thereof (an anhydride, esterified product, halogenated product of the polyvalent carboxylic acid). Selected from one or two or more compounds (polyhydric carboxylic acid component) selected from, 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 two or more compounds (polyhydric alcohol component) are condensed.

  Examples of compounds that can be employed as the polyvalent carboxylic acid component include oxalic acid, malonic acid, difluoromalonic acid, alkylmalonic acid, succinic acid, tetrafluorosuccinic acid, alkylsuccinic acid, (±) -malic acid, meso. -Tartaric acid, itaconic acid, maleic acid, methylmaleic acid, fumaric acid, methylfumaric acid, acetylenedicarboxylic acid, glutaric acid, hexafluoroglutaric acid, methylglutaric acid, glutaconic acid, adipic acid, dithioadipic acid, methyladipic acid, dimethyl Adipic acid, tetramethyladipic acid, methyleneadipic acid, muconic acid, galactaric acid, pimelic acid, suberic acid, perfluorosuberic acid, 3,3,6,6-tetramethylsuberic acid, azelaic acid, sebacic acid, perfluoro Sebacic acid, brassic acid, dodecyl dicar Aliphatic dicarboxylic acids such as acid, tridecyl dicarboxylic acid, tetradecyl dicarboxylic acid; cycloalkyl dicarboxylic acid (for example, 1,4-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid), 1,4- (2- Alicyclic dicarboxylic acids such as norbornene) dicarboxylic acid, 5-norbornene-2,3-dicarboxylic acid (hymic acid), adamantane dicarboxylic acid, spiroheptane dicarboxylic acid; phthalic acid, isophthalic acid, dithioisophthalic acid, methylisophthalic acid, Dimethylisophthalic acid, chloroisophthalic acid, dichloroisophthalic acid, terephthalic acid, methylterephthalic acid, dimethylterephthalic acid, chloroterephthalic acid, bromoterephthalic acid, naphthalenedicarboxylic acid, oxofluorenedicarboxylic acid, anthracenedical Bonic acid, biphenyl dicarboxylic acid, biphenylene dicarboxylic acid, dimethyl biphenylene dicarboxylic acid, 4,4 "-p-terephenylene dicarboxylic acid, 4,4" -p-quarelphenyl 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) dipropion Aromatic dicarboxylic acids such as acid, 4,4′-bibenzyldiacetic acid, 3,3 ′ (4,4′-bibenzyl) dipropionic acid, oxydi-p-phenylenediacetic acid; Acid anhydrides of any of the polyhydric carboxylic acids mentioned above (Eg alkyl esters). It can be a monoester, a diester or the like. ); Acid halides corresponding to any of the polyvalent carboxylic acids described above (for example, dicarboxylic acid chloride); and the like.

  Preferable examples of the compound that can be employed as the polyvalent carboxylic acid component include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic 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, monoalcohols having 1 to 3 carbon atoms) Ester) and the like.

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

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

  As the polyester resin, a commercially available product name “Vylonal MD-1480” manufactured by Toyobo Co., Ltd. can be used.

  The antistatic layer (topcoat layer) is a resin other than a polyester resin as a binder as long as the performance of the pressure-sensitive adhesive sheet (surface protective film) disclosed herein (for example, performance such as antistatic properties) is not significantly impaired. (For example, one or more resins selected from acrylic resins, acrylic-urethane resins, acrylic-styrene resins, acrylic-silicone resins, silicone resins, polysilazane resins, polyurethane resins, fluororesins, polyolefin resins, etc.) Further, it can be contained. A preferred embodiment of the technology disclosed herein is a case where the binder of the antistatic layer is substantially composed only 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 appropriate.

<Lubricant>
The antistatic layer (topcoat layer) preferably uses a fatty acid amide as a lubricant. By using fatty acid amide as a lubricant, a further release treatment (for example, a treatment in which a known release treatment agent such as a silicone release agent or a long-chain alkyl release agent is applied and dried) is applied to the surface of the antistatic layer. Even in the case where the coating is not performed, an antistatic layer (topcoat layer) having both sufficient slipping property and printing adhesion can be obtained, which can be a preferable mode. Thus, the aspect in which the surface of the antistatic layer is not further peeled can prevent whitening due to the peeling treatment agent (for example, whitening due to storage under heating and humidification conditions). This is preferable. It is also advantageous from the viewpoint 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-oleylparticic 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 biscapric acid amide, ethylene bis lauric acid amide, ethylene bis stearic acid Amides, ethylene bishydroxystearic acid amides, ethylene bisbehenic acid amides, hexamethylene bisstearic acid amides, hexamethylene bisbehenic acid amides, hexamethylene hydroxystearic acid amides N, N′-distearyl adipic acid amide, N, N′-distearyl sebacic acid amide, ethylene bisoleic acid amide, ethylene biserucic acid amide, hexamethylene bisoleic acid amide, N, N′-dioleyl Examples include adipic acid amide, N, N′-dioleyl sebacic acid amide, m-xylylene bisstearic acid amide, m-xylylene bishydroxystearic acid amide, N, N′-stearyl isophthalic acid amide, and the like. These lubricants may be used alone or in combination of two or more.

  The ratio of the lubricant to the whole antistatic layer can be 1 to 50% by mass, and usually 5 to 40% by mass is appropriate. When there is too little content rate of a lubricant, it exists in the tendency for slipperiness to fall easily. If the content of the lubricant is too large, the print adhesion may be lowered.

  The technique disclosed herein can be carried out in a mode in which the antistatic layer (topcoat layer) contains other lubricant in addition to the fatty acid amide, as long as the application effect is not greatly impaired. Examples of such other lubricants include various waxes such as petroleum wax (paraffin wax, etc.), mineral wax (montan wax, etc.), higher fatty acid (cellotic acid, etc.), and neutral fat (palmitic acid triglyceride, etc.). It is done. Alternatively, in addition to the wax, a general silicone-based lubricant, a fluorine-based lubricant, and the like may be supplemented. The technology disclosed herein can be preferably implemented in an embodiment that does not substantially contain such a silicone-based lubricant, a fluorine-based lubricant and the like. However, as long as the application effect of the technology disclosed herein is not significantly impaired, the inclusion of a silicone compound used for a purpose other than the lubricant (for example, as an antifoaming agent for a coating material for forming an antistatic layer described later) Is not to be excluded.

<Crosslinking agent>
The antistatic layer preferably contains an isocyanate-based crosslinking agent as a crosslinking agent. By using the isocyanate-based crosslinking agent, the water-soluble polyaniline sulfonic acid, which is an essential component when forming the antistatic layer, can be fixed in the binder, has excellent water resistance, and further improves printing adhesion. The effect can be realized.

  As the isocyanate-based crosslinking agent, it is preferable to use a blocked isocyanate-based crosslinking agent that 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 general pressure-sensitive adhesive layers and antistatic layers (topcoat layers) (for example, used in the above-mentioned pressure-sensitive adhesive layers). Isocyanate compounds (isocyanate-based cross-linking agents)) alcohols, phenols, thiophenols, amines, imides, oximes, lactams, active methylene compounds, mercaptans, imines, ureas, diaryl compounds And those blocked with sodium bisulfite can be used.

  The antistatic layer in the technology disclosed herein includes an antistatic component, an antioxidant, a colorant (pigment, dye, etc.), a fluidity modifier (thixotropic agent, thickener, etc.), a film-forming as necessary. It may contain additives such as auxiliaries, surfactants (antifoaming agents, etc.), preservatives and the like.

<Formation of antistatic layer>
The antistatic layer (topcoat layer) is a liquid composition (for forming an antistatic layer) in which essential components such as the conductive polymer component and additives used as necessary are dissolved in an appropriate solvent (such as water). Can be suitably formed by a technique including applying the coating material) to the support film. For example, a method of applying the coating material to the first surface of the support film and drying it, and performing a curing treatment (heat treatment, ultraviolet treatment, etc.) as necessary can be preferably employed. 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%). 1 mass%) is appropriate. In the case of forming an antistatic layer with a small thickness, it is preferable that the NV of the coating material is, for example, 0.05 to 0.50 mass% (for example, 0.10 to 0.40 mass%). Thus, a more uniform antistatic layer can be formed by using a low NV coating material.

  As the solvent constituting the coating material for forming the antistatic layer, a solvent capable of stably dissolving the components for forming the antistatic layer is preferable. Such a 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 and xylene; aliphatic or alicyclic alcohols such as methanol, ethanol, n-propanol, isopropanol, and cyclohexanol; alkylene glycol monoalkyl ether (for example, ethylene glycol monomethyl ether) , Ethylene glycol monoethyl ether), and glycol ethers such as dialkylene glycol monoalkyl ether; 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 to 500 nm, preferably 3 to 100 nm, more preferably 3 to 60 nm. If the thickness of the antistatic layer is too small, it becomes difficult to form the antistatic layer uniformly (for example, the thickness of the antistatic layer varies greatly depending on the location). The appearance of the film) can easily become uneven. On the other hand, if it is too thick, the properties (optical properties, dimensional stability, etc.) of the support film may be affected.

In a preferable embodiment of the pressure-sensitive adhesive sheet (surface protective film) disclosed herein, the surface resistance value (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 further 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 in processing or transporting an article that dislikes static electricity such as a liquid crystal cell or a semiconductor device. The surface resistance value can be calculated from the surface resistance value measured under an atmosphere of 23 ° C. and 50% RH using a commercially available insulation resistance measuring device.

  The pressure-sensitive adhesive sheet (surface protective film) disclosed herein has a property that the back surface (surface of the antistatic layer) can be easily printed with water-based ink or oil-based ink (for example, using an oil-based marking pen). preferable. Such an adhesive sheet describes the identification number of the adherend to be protected on the surface adhesive sheet in the course of processing or transporting the adherend (for example, an optical component) performed with the adhesive sheet attached. 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 for oil-based inks containing pigments. Moreover, it is preferable that the printed ink is difficult to be removed by rubbing or transfer (that is, excellent in print adhesion). The pressure-sensitive adhesive sheet disclosed herein preferably has a solvent resistance that does not cause a noticeable change in appearance even if the print is wiped with alcohol (for example, ethyl alcohol) when the print is corrected or erased. .

  The pressure-sensitive adhesive sheet (surface protective film) disclosed herein can be implemented in an embodiment that further includes 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 a space between the first surface (back surface) of the support film and the antistatic layer, a space between the second surface (front surface) of the support film and the pressure-sensitive adhesive layer, and the like. The layer disposed between the back surface of the support film and the antistatic layer can be, for example, a layer containing an antistatic component (the above-described antistatic layer). The layer disposed between the front surface of the support film and the pressure-sensitive adhesive layer can be, for example, an undercoat layer (anchor layer) or an antistatic layer that enhances the anchoring property of the pressure-sensitive adhesive layer with respect to the second surface. The pressure-sensitive adhesive sheet may be configured such that an antistatic layer is disposed on the front surface of the support film, an anchor layer is disposed on the antistatic layer, and a pressure-sensitive adhesive layer is disposed thereon.

  The optical member of the present invention is preferably protected by the pressure-sensitive adhesive sheet. Since the pressure-sensitive adhesive sheet is excellent in shearing force, curling of the adherend (optical member) to which the pressure-sensitive adhesive sheet is bonded can be suppressed, and since the handleability is excellent, the pressure-sensitive adhesive sheet is useful.

  Hereinafter, examples and the like specifically showing the configuration and effects of the present invention will be described, but the present invention is not limited to these. In addition, about the mixing | blending content in an Example etc. and characteristic evaluation, it measured as follows. In Table 1, the physical property values of the (meth) acrylic polymer used in the pressure-sensitive adhesive composition and the blending ratio of the pressure-sensitive adhesive composition are shown. In Table 2, the blending content of the antistatic layer is shown. Shows the evaluation results of the characteristics of the pressure-sensitive adhesive sheet.

<Evaluation>
The specific measurement / 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 used in the present invention were measured using a GPC apparatus (HLC-8220GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.

Sample concentration: 0.2% by mass (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow rate: 0.6 ml / min
Measurement temperature: 40 ° C
column:
Sample column; TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column; TSKgel SuperH-RC (1)
Detector: Differential refractometer (RI)
In addition, the weight average molecular weight (Mw) and the number average molecular weight (Mn) were calculated | required in the polystyrene conversion value.

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

Formula: 1 / (Tg + 273) = Σ [Wn / (Tgn + 273)]
[Wherein, Tg (° C.) is the glass transition temperature of the copolymer, Wn (−) is the mass fraction of each monomer, Tgn (° C.) is the glass transition temperature of the homopolymer of each monomer, and n is the type of each monomer Represents. ] Literature values:
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, “Synthesis / design of acrylic resin and development of new applications” (published by Central Management Development Center Publishing Department) and “Polymer Handbook” (John Wiley & Sons) were referred to.

<Measurement of shear force>
After the pressure-sensitive adhesive sheet is cut to a size of 10 mm in width and 100 mm in length and the separator is peeled off, a TAC polarizing plate (Nitto Denko Corporation) is used so that the pressure-sensitive adhesive (adhesion) area of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet is 1 cm ^2. Manufactured, SEG1423DU polarizing plate, width: 25 mm, length: 100 mm), and left at room temperature (23 ° C. × 50% RH) for 30 minutes, and then pulled in the shear direction at a peeling rate of 0.06 m / min. The maximum load (N / cm ² ) at that time was defined as the shear force.

The shearing 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 shearing force is within the above range, it can withstand the force in the shearing direction that occurs when the adherend tries to curl, and the adhesive sheet does not slip or slip, and the adherend is curled. Since it can suppress, it is preferable.

<Measurement of surface resistance value>
Measurement was performed in accordance with JIS-K-6911 using a resistivity meter (manufactured by Mitsubishi Chemical Analytic, Hiresta UP MCP-HT450 type) in an atmosphere of temperature 23 ° C. and humidity 50% RH.

The surface resistance value (Ω / □) on the surface of the antistatic layer in the present invention is initially (before aging treatment), and is allowed to stand at room temperature (23 ° C. × 50% RH) × 1 week (7 days) (time lapse). In the case of (after treatment), 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 . The pressure-sensitive adhesive sheet (surface protective film) exhibiting a surface resistance value within the above range is suitably used as a pressure-sensitive adhesive sheet used in the processing or transporting of articles that 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, the separator is peeled off, and then bonded to the acrylic plate 4 (thickness: 2 mm, width: 70 mm, length: 100 mm) that has been neutralized beforehand. The polarizing plate 3 (manufactured by Nitto Denko Corporation, SEG1423DU polarizing plate, width: 70 mm, length: 100 mm) was pressure-bonded with a hand roller so that one end protruded 30 mm from the surface (TAC surface).

  After being left for 1 day at 23 ° C. × 50% RH, the sample was set at a predetermined position as shown in FIG. One end that protruded 30 mm was fixed to an automatic winder and peeled 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 (peeling band voltage: absolute value, kV) generated at this time was measured with a potential measuring device 1 (KSD-0103, manufactured by Kasuga Denki Co., Ltd.) fixed at the center of the polarizing plate. The measurement was performed in an environment of 23 ° C. × 50% RH.

  At a peeling angle of 150 ° and a peeling speed of 30 m / min after the adhesive surface of the pressure-sensitive adhesive layer used in the pressure-sensitive adhesive sheet was pasted for 1 day at 23 ° C. × 50% RH with respect to the TAC surface (polarizing plate surface). The potential (peeling band voltage: kV, absolute value) of the polarizing plate surface generated when peeling (high-speed peeling) is preferably 1.0 kV or less, more preferably 0.8 kV or less, and even more preferably 0.6 kV or less. If the stripping 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 on the surface of the antistatic layer using an X stamper manufactured by Shachihata Co., Ltd. in a measurement environment of 23 ° C. × 50% RH, a Nichiban cello tape (registered trademark) was applied on the printed surface. Next, peeling is performed under conditions of a peeling speed of 30 m / min and a peeling angle of 180 °. Then, the surface after peeling was visually observed, and x (printability failure) when 50% or more of the print area was peeled off, and ○ (good printability) when 50% or more of the print area remained without peeling. ).

<Preparation method>
In the following, specific methods for synthesizing (meth) acrylic polymers and methods for preparing pressure-sensitive adhesive compositions are described.

<Preparation of 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, 0.22 parts by mass of 2,2′-azobisisobutyronitrile as a polymerization initiator, 150 parts by mass of ethyl acetate, nitrogen gas was introduced while gently stirring, A polymerization reaction was carried out for 6 hours while maintaining the liquid temperature at around 65 ° C. to prepare a (meth) acrylic polymer solution (40% by mass). The (meth) acrylic polymer had a weight average molecular weight (Mw) of 520,000 and a glass transition temperature (Tg) of −68 ° C.

  The above (meth) acrylic polymer solution (40% by mass) is diluted with ethyl acetate to 20% by mass, and 500 parts by mass (100 parts by mass of solid content) of this solution is used as a crosslinking agent. 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% by mass ethyl acetate solution) as a crosslinking catalyst ( 0.03 parts by mass of solid content) was added and mixed and stirred to prepare an adhesive composition 1 (solution).

<Preparation of aqueous solution for antistatic layer (back treatment agent A)>
Polyester resin Vylonal 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.) as a conductive polymer, and hexamethylene blocked with diisopropylamine as a crosslinking agent Isocyanurate of diisocyanate, lubricant, oleic amide in water / ethanol (1/3) mixed solvent, binder in solid content of 100 parts by mass, conductive polymer in solid content of 75 parts by mass, and crosslinker in solid form 10 parts by weight and 30 parts by weight of solid lubricant were added and stirred for about 20 minutes to mix thoroughly. In this way, an antistatic layer aqueous solution having an NV of about 0.4% by mass was prepared.

<Preparation of aqueous solution for antistatic layer (back treatment agent B)>
Polyester resin Vylonal MD-1480 (25% aqueous solution, manufactured by Toyobo Co., Ltd.) as a binder, polyanilinesulfonic acid (aquapass, weight average molecular weight 40,000, manufactured by Mitsubishi Rayon Co.) as a conductive polymer, and hexamethylene blocked with diisopropylamine as a crosslinking agent A diisocyanate isocyanurate body in a water / ethanol (1/3) mixed solvent, a binder in a solid content of 100 parts by mass, a conductive polymer in a solid content of 75 parts by mass, and a crosslinking agent in a solids content of 10 parts by mass. In addition, it was stirred for about 20 minutes and mixed well. In this way, an antistatic layer aqueous solution having an NV of about 0.4% by mass was prepared.

<Supporting 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 the support film 1.

<Preparation of Support Film 2 with Antistatic Layer>
One surface (first surface) of the support film 1 is subjected to corona treatment on 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. An aqueous solution of either the back treatment agent A or B) was applied so that the thickness after drying was 30 nm. The coated material was heated to 130 ° C. for 1 minute and 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 side of the support film 1 and heated at 130 ° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 15 μm. Next, a silicone-treated surface of a polyethylene terephthalate film (thickness 25 μm), which is a separator having a silicone treatment on one side, was bonded to the surface of the pressure-sensitive adhesive layer to produce a pressure-sensitive adhesive sheet (surface protective film).

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

  In accordance with the above evaluation method, the shear force of the produced pressure-sensitive adhesive sheet, the peeling voltage, and the antistatic layer, the presence or absence of aggregates in the solution when producing the antistatic layer, the initial (before aging treatment), and the time The surface resistance and the print adhesion were evaluated, and the evaluation results are shown in Tables 2 and 3.

Abbreviations in Table 1 and Table 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 group-containing (meth) acrylic monomer)
HBA: 4-hydroxybutyl acrylate (hydroxyl group-containing (meth) acrylic monomer)
C / HX: Nippon Polyurethane Co., Ltd., trade name “Coronate HX”, aliphatic isocyanate compound, hexamethylene diisocyanate isocyanurate (crosslinking agent)
HDPTFI: 1-hexadecylpyridinium bis (trifluoromethanesulfonyl) imide (melting point: 34 ° C.) (onium salt, carbon number of alkyl group of onium cation constituting onium salt: 16)
HDMITFI: 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)
HDMIHP: 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: Product name “Adekapluronic 25R-1” manufactured by ADEKA (number average molecular weight 2800, ethylene oxide group content: 10% by mass)
KF355A: manufactured by 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 all the examples were excellent in shearing force and antistatic property. In Examples 3 and 4 having an antistatic layer, it was further confirmed that the surface resistance and the print adhesion were excellent.

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

DESCRIPTION OF SYMBOLS 1 Potential measuring device 2 Adhesive sheet 3 Polarizing plate 4 Acrylic board 5 Fixing stand

Claims (6)

As an onium salt having a melting point of 150 ° C. or lower, a crosslinking agent, and a base polymer, a glass transition temperature of (meth) acrylic polymer having a temperature of 0 ° C. or lower is contained,
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 said onium salt is a pressure-sensitive adhesive sheet having an adhesive layer formed from the tacky Chakuzai composition you containing onium cation having at least one alkyl group having 8 or more carbon atoms, on one side of the support film,
Having an antistatic layer on one side of the support film opposite to the adhesive layer;
The antistatic layer is formed from an antistatic agent composition containing polyaniline sulfonic acid as a conductive polymer component, a polyester resin as a binder, a fatty acid amide as a lubricant, and an isocyanate-based crosslinking agent as a crosslinking agent. Adhesive sheet. The pressure-sensitive adhesive sheet according to claim 1, wherein the pressure-sensitive adhesive composition contains a compound having an alkylene oxide group having a number average molecular weight of 10,000 or less. The pressure-sensitive adhesive sheet according to claim 2, wherein the compound having an alkylene oxide group is an organopolysiloxane having an alkylene oxide group. The (meth) acrylic polymer, hydroxyl group, and a pressure-sensitive adhesive sheet according to claim 1, wherein the benzalkonium that having a carboxyl group. Laminating the adhesive area 1 cm ² of the previous SL adhesive layer TAC polarizing plate, the shearing force at the time of peeling in the shear direction at a peeling speed of 0.06 m / min after patch 30 minutes at 23 ° C. is, 8.5 N / cm ^{It is 2} or more, The adhesive sheet in any one of Claims 1-4 characterized by the above-mentioned . Optical member, characterized in that it is protected by the adhesive sheet according to claim 1.

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