JP2018123330A - Adhesive composition, adhesive sheet, and optical member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition which can achieve improved shear force at low speed peeling, and improved peeling antistatic properties, an adhesive sheet prepared using the same, and an optical member prepared using the same.SOLUTION: An adhesive composition comprises a (meth) acrylic polymer comprising a (meth) acrylic monomer having a C1-14 alkyl group of 40 mass% or more, a nitrogen-containing monomer of 0.5-20 mass%, and an alkylene oxide group-containing monomer of 0.5-40 mass%, and organic salt and/or alkali metal salt with a melting point of 150°C or less.SELECTED DRAWING: None

Description

  The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet, and an optical member. In particular, the pressure-sensitive adhesive sheet obtained from the pressure-sensitive adhesive composition is suitable for applications that are affixed to plastic products and the like that are susceptible to static electricity, and in particular, optical members (for example, polarizing plates used for liquid crystal displays, etc. It is useful as a surface protective film used for the purpose of protecting the surface of a wave plate, a phase difference plate, an optical compensation film, a reflection sheet, a brightness enhancement film, and the like.

  The surface protective film is generally used for the purpose of sticking to a body to be protected through an adhesive applied to the side of the protective film and preventing scratches and dirt generated during processing and transportation of the body to be protected. For example, a panel of a liquid crystal display is formed by bonding an optical member such as a polarizing plate or a wavelength plate to a liquid crystal cell via an adhesive. In these optical members to be bonded to the liquid crystal cell, a protective film is bonded via an adhesive for the purpose of preventing scratches and dirt.

  Then, the protective film is peeled off and removed at a stage where the protective film is no longer necessary, for example, by bonding the optical member to the liquid crystal cell. In general, since a protective film and an optical member are made of a plastic material, they have high electrical insulation and generate static electricity during friction and peeling. Accordingly, static electricity is generated when the protective film is peeled off from the optical member such as a polarizing plate. When a voltage is applied to the liquid crystal while static electricity remains, the alignment of liquid crystal molecules is lost or the panel is damaged. Therefore, in order to prevent such problems, the surface protective film is subjected to various antistatic treatments.

  For example, a method is disclosed in which one or more surfactants are added to the pressure-sensitive adhesive layer, and the surfactant is transferred from the pressure-sensitive adhesive layer to the adherend to prevent charging (for example, see Patent Document 1). . However, in this invention, the surfactant is easily bleed on the surface of the pressure-sensitive adhesive layer, and when applied to a protective film, there is a concern about contamination of the adherend. Therefore, when an adhesive layer to which a low molecular surfactant is added is applied to the protective film for an optical member, it is difficult to develop sufficient antistatic properties without impairing the optical properties of the optical member.

  Further, a method is disclosed in which an antistatic agent comprising a polyether polyol and an alkali metal salt is added to an acrylic pressure-sensitive adhesive to suppress bleeding of the antistatic agent on the surface of the pressure-sensitive adhesive (for example, see Patent Document 2). . However, even in this method, bleeding of the antistatic agent is unavoidable. As a result, when it is actually applied to a surface protective film, if it is subjected to treatment with time or high temperature, contamination of the adherend due to bleeding phenomenon. May occur.

  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 during low-speed peeling is required.

JP-A-9-165460 JP-A-6-128539

  Accordingly, the present invention has been made in view of the above circumstances, and as a result of extensive research, it is an object of the present invention to provide a pressure-sensitive adhesive composition, a pressure-sensitive adhesive sheet, and an optical member that can achieve shearing force at low-speed peeling and peeling antistatic properties. And

  That is, in the pressure-sensitive adhesive composition of the present invention, as a monomer component, a (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms is 40% by mass or more, a nitrogen-containing monomer is 0.5 to 20% by mass, and And a (meth) acrylic polymer containing 0.5 to 40% by mass of an alkylene oxide group-containing monomer, an organic salt having a melting point of 150 ° C. or lower, and / or an alkali metal salt.

  In the pressure-sensitive adhesive composition of the present invention, the organic salt having a melting point of 150 ° C. or lower is preferably at least one selected from the group consisting of nitrogen-containing onium salts, sulfur-containing onium salts, and phosphorus-containing onium salts.

  In the pressure-sensitive adhesive composition of the present invention, the (meth) acrylic polymer preferably contains a carboxyl group-containing monomer in an amount of 0.01% by mass to less than 1% by mass as a monomer component.

  The pressure-sensitive adhesive composition of the present invention preferably further contains an alkylene oxide group-containing compound not containing an organopolysiloxane having a number average molecular weight of 10,000 or less.

  The pressure-sensitive adhesive composition of the present invention is preferably formed by forming a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition on one side or both sides of the support.

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

  The pressure-sensitive adhesive composition of the present invention is obtained by containing a (meth) acrylic polymer containing a specific monomer in a specific ratio, an organic salt having a melting point of 150 ° C. or less, and / or an alkali metal salt. The pressure-sensitive adhesive layer (pressure-sensitive adhesive sheet) is excellent in shearing force at the time of low-speed peeling, and therefore can suppress unnecessary curls and unintended curls on the adherend when bonded to the adherend. Furthermore, since it is excellent in antistatic properties against peeling, it is particularly useful for surface protection of optical members.

It is explanatory drawing which shows the measuring method of peeling voltage.

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

  In the pressure-sensitive adhesive composition of the present invention, as a monomer component, a (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms is 40% by mass or more, a nitrogen-containing monomer is 0.5 to 20% by mass, and alkylene. It contains a (meth) acrylic polymer containing 0.5 to 40% by mass of an oxide group-containing monomer, an organic salt having a melting point of 150 ° C. or less, and / or an alkali metal salt. The pressure-sensitive adhesive composition of the present invention contains a (meth) acrylic polymer containing a specific proportion of a specific monomer, thereby being excellent in shearing force during low-speed peeling, and having an organic salt having a melting point of 150 ° C. or lower, and By containing an alkali metal salt, a pressure-sensitive adhesive layer (pressure-sensitive adhesive sheet) having excellent peeling antistatic properties can be obtained, which is useful. Below, the raw material contained in a specific adhesive layer and the manufacturing method of an adhesive layer (adhesive sheet) are demonstrated.

<(Meth) acrylic polymer>
The pressure-sensitive adhesive composition of the present invention contains, as a monomer component, a (meth) acrylic polymer containing 40% by mass or more of a (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms. . By blending the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms as a monomer component, it becomes easy to control the adhesive force to an adherend (protected body) to be low, An adhesive sheet excellent in removability is obtained.

  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. (Meth) acrylic monomers having an alkyl group of 6 to 14 carbon atoms are preferred. In particular, by using a (meth) acrylic monomer having an alkyl group having 6 to 14 carbon atoms as a main component (the most component as a monomer component), the adhesive strength to the adherend is controlled to be low. Becomes easy and has excellent removability.

  The (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms may be used alone or as a mixture of two or more thereof. Containing 40 mass% or more of the (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, preferably 50 mass% or more, more preferably 100 mass% of the total amount of monomer components , 60% by mass or more, more preferably 70 to 95% by mass. When it is less than 40% by mass, the appropriate wettability of the pressure-sensitive adhesive composition and the cohesive strength of the pressure-sensitive adhesive layer are deteriorated, which is not preferable.

  The pressure-sensitive adhesive composition of the present invention is characterized by containing a (meth) acrylic polymer containing 0.5 to 20% by mass of a nitrogen-containing monomer as a monomer component. By blending the nitrogen-containing monomer as a monomer component, the cohesive force of the pressure-sensitive adhesive (layer) obtained by containing the (meth) acrylic polymer can be improved, and an excellent shearing force can be expressed. Is also possible (curl adjustability) and is useful. Furthermore, the nitrogen salt contained in the (meth) acrylic polymer is coordinated with an organic salt or alkali metal salt (hereinafter sometimes simply referred to as “organic salt”) having a melting point of 150 ° C. or less. It is presumed that an excellent shearing force can be realized by making it difficult for organic salts to bleed.

  Specific examples of the nitrogen-containing monomer include amide group-containing monomers, amino group-containing monomers, imide group-containing monomers, and cyano group-containing monomers.

  Examples of the amide group-containing monomer include acrylamide, methacrylamide, N-methyl (meth) acrylamide, N-isopropyl (meth) acrylamide, Nt-butyl (meth) acrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacrylamide, N, N-dipropylacrylamide, N, N-diisopropyl (meth) acrylamide, N, N-dibutyl (meth) acrylamide, N -Ethyl-N-methyl (meth) acrylamide, N-methyl-N-propyl (meth) acrylamide, N-methyl-N-isopropyl (meth) acrylamide, N-methylol acrylamide, diacetone acrylamide, N-vinylacetami N, N'-methylenebisacrylamide, N, N-dimethylaminopropyl (meth) 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, diacetone acrylamide N Vinylpyrrolidone, etc. N- vinyl caprolactam.

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

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

  The nitrogen-containing monomer may be used alone or in combination of two or more, but the nitrogen-containing monomer is used with respect to 100% by mass of the total amount of monomer components of the (meth) acrylic polymer. Is 0.5 to 20% by mass, preferably 0.7 to 16% by mass, more preferably 0.9 to 10% by mass, and still more preferably 1 to 5% by mass. When the content of the nitrogen-containing monomer is less than 0.5% by mass, the effect of suppressing bleeding such as organic salts and the effect of reducing the contamination of the adherend (protected body) may not be obtained, which is not preferable. On the other hand, when the content of the nitrogen-containing monomer is more than 20% by mass, the pressure-sensitive adhesive layer (pressure-sensitive adhesive sheet) has high adhesive strength, and particularly when the pressure-sensitive adhesive sheet is applied as a surface protective film, This may cause the adherend to be broken, which is not preferable. Moreover, when there is more content of the said nitrogen-containing monomer than 20 mass%, interaction with organic salt etc. will become large, ion conduction will be prevented, and peeling antistatic property may fall, and is unpreferable.

  The pressure-sensitive adhesive composition of the present invention contains a (meth) acrylic polymer containing 0.5 to 40% by mass of an alkylene oxide group-containing monomer as a monomer component. By blending the alkylene oxide group-containing monomer as a monomer component, it is possible to efficiently achieve both the effect of reducing the contamination of the adherend (protected body) and the effect of preventing anti-peeling, and this is preferable.

  The alkylene oxide group-containing monomer may be used alone or in combination of two or more. However, the alkylene is based on 100% by mass of the total amount of monomer components of the (meth) acrylic polymer. The oxide group-containing monomer is contained in an amount of 0.5 to 40% by mass, preferably 0.6 to 38% by mass, more preferably 0.7 to 36% by mass, still more preferably 0.8 to 34% by mass. %. When the content of the alkylene oxide group-containing monomer exceeds 40% by mass, the interaction with the organic salt or the like is increased, ionic conduction is hindered, and peeling antistatic property is lowered, which is not preferable. Further, if it is less than 0.5% by mass, the effect of suppressing bleeding out of organic salts and the like and the effect of reducing the contamination of the adherend (protected body) may not be sufficiently obtained, which is not preferable.

  The average addition mole number of the oxyalkylene unit of the alkylene oxide group-containing monomer is preferably 1 to 40, and preferably 3 to 40 from the viewpoint of compatibility with an organic salt or the like that is an antistatic component. More preferably, it is more preferably 4-35, and particularly preferably 5-30. When the average added mole number is 1 or more, the effect of reducing the contamination of the adherend (protected body) tends to be obtained efficiently. Moreover, when the said average added mole number is larger than 40, since interaction with organic salt etc. is large and there exists a tendency for the viscosity of an adhesive composition to rise and for coating to become difficult, it is unpreferable. The terminal of the oxyalkylene chain may remain a hydroxyl group or may be substituted with another functional group, but for appropriate control of the crosslinking density, for example, an alkyl group or a phenyl group is substituted. It is more preferable.

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

  More preferably, the alkylene oxide group-containing monomer is a reactive monomer having an ethylene oxide group. By using a (meth) acrylic polymer having a reactive monomer having an ethylene oxide group as the base polymer, the compatibility between the base polymer and the organic salt is improved, bleed to the adherend is suitably suppressed, and low A fouling pressure-sensitive adhesive composition is obtained.

  Examples of the alkylene oxide group-containing monomer include (meth) acrylic acid alkylene oxide adducts and reactive surfactants having reactive substituents such as acryloyl group, methacryloyl group, and allyl group in the molecule. .

  Specific examples of the (meth) acrylic acid alkylene oxide adduct include, for example, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, polyethylene glycol-polypropylene glycol (meth) acrylate, polyethylene glycol-polybutylene glycol (meta ) Acrylate, polypropylene glycol-polybutylene glycol (meth) acrylate, methoxy polyethylene glycol (meth) acrylate, ethoxy polyethylene glycol (meth) acrylate, butoxy polyethylene glycol (meth) acrylate, octoxy polyethylene glycol (meth) acrylate, lauroxy polyethylene Glycol (meth) acrylate, stearoxy polyethylene glycol Lumpur (meth) acrylate, phenoxy polyethylene glycol (meth) acrylate, methoxy polypropylene glycol (meth) acrylate, octoxypolyethylene glycol - polypropylene glycol (meth) acrylate. Of these, methoxypolyethylene glycol monoacrylate, ethoxydiethylene glycol acrylate, and the like are preferably used.

  In the pressure-sensitive adhesive composition of the present invention, the (meth) acrylic polymer preferably contains a carboxyl group-containing monomer in an amount of 0.01% by mass to less than 1% by mass as a monomer component. As the carboxyl group-containing monomer, one type or two or more types can be used.

  By using the above carboxyl group-containing monomer, the crosslinking reaction of the resulting pressure-sensitive adhesive (layer) can be promoted, and the aging time after forming the pressure-sensitive adhesive layer (the time required for actual use characteristics to be manifested after forming the pressure-sensitive adhesive layer) The pressure-sensitive adhesive sheet with excellent productivity can be obtained, which is useful. In addition, when using a carboxyl group-containing monomer, it becomes a preferable aspect to adjust so that the acid value of the said (meth) acrylic-type polymer may be 29 or less. When the acid value of the (meth) acrylic polymer exceeds 29, the carboxyl group contained in the (meth) acrylic polymer interacts with the antistatic component, and the antistatic properties tend to deteriorate.

  The carboxyl group-containing monomer is preferably contained in an amount of 0.01% by mass to less than 1% by mass, more preferably 0.05% by mass or more, with respect to 100% by mass of the total amount of monomer components of the (meth) acrylic polymer. It is less than 0.2% by mass. Within the above range, the crosslinking reaction of the pressure-sensitive adhesive composition can be effectively promoted, and the aging time after forming the pressure-sensitive adhesive layer (the time required for actual use characteristics to be manifested after forming the pressure-sensitive adhesive layer) can be shortened. It is possible to obtain an adhesive sheet excellent in productivity and useful.

  Examples of the carboxyl group-containing monomer include (meth) acrylic acid, carboxylethyl (meth) acrylate, carboxylpentyl (meth) acrylate, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, and 2- (meth) acrylic acid. Leuoxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxyethyl maleic acid, carboxypolycaprolactone mono (meta ) Acrylate, 2- (meth) acryloyloxyethyl tetrahydrophthalic acid, itaconic acid, maleic acid, fumaric acid and the like.

  The (meth) acrylic polymer preferably contains a hydroxyl group-containing monomer as a monomer component. As said hydroxyl group containing monomer, 1 type (s) or 2 or more types can be used.

  By using the hydroxyl group-containing monomer, it becomes easy to control the crosslinking of the pressure-sensitive adhesive composition, and it becomes easy to control the balance between the improvement of wettability by flow and the reduction of the adhesive strength in peeling. Furthermore, unlike carboxyl groups and sulfonate groups that can generally act as cross-linking sites, hydroxyl groups have an appropriate interaction with organic salts, which are antistatic components (antistatic agents), and therefore have antistatic properties that prevent peeling. Also in terms of surface, it can be suitably used.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, and 8-hydroxyoctyl. (Meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxy Examples thereof include ethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether. In particular, it is preferable to use a hydroxyl group-containing monomer having 4 or more carbon atoms in the alkyl group because light release at the time of high-speed peeling is easy.

  The hydroxyl group-containing monomer is preferably contained in an amount of 0 to 15% by mass, more preferably 0.5 to 10% by mass, and still more preferably, with respect to 100% by mass of the total amount of monomer components of the (meth) acrylic polymer. Is 1-8 mass%. Within the above range, it is preferable to control the balance between the wettability of the pressure-sensitive adhesive composition and the cohesive force and shearing force of the pressure-sensitive adhesive layer to be obtained.

  In addition, as another polymerizable monomer component, the Tg is 0 ° C. or lower (usually −100 ° C. or higher) for the reason that it is easy to balance the adhesive performance, and the glass transition temperature or peeling of the (meth) acrylic polymer. It can be used in the range which does not impair the effect of this invention, such as the polymerizable monomer for adjusting property.

  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, Tg is a component having a functional group that acts as a crosslinking base point, such as a cohesive force, shearing force, heat resistance improving component such as vinyl ester monomer, aromatic vinyl monomer, epoxy group-containing monomer, vinyl ether monomer, etc. For the purpose of control, methoxyethyl acrylate, ethoxyethyl acrylate, butoxyethyl acrylate, and phenoxyethyl acrylate can be appropriately used. These polymerizable monomers may be used alone or in combination of two or more.

  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 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.

  The other polymerizable monomer can be used in an amount of 0 to 40 parts by mass, preferably 0 to 20 parts by mass, based on 100% by mass of the total amount of monomer components of the (meth) acrylic polymer. It is more preferable that it is 10 mass parts.

  The method for polymerizing the (meth) acrylic polymer using the monomer component is not particularly limited and can be polymerized by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization or the like. In particular, solution polymerization is a more preferable embodiment from the viewpoints of workability and characteristics such as low contamination to the adherend (protected body). Further, the polymer obtained may be any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, and the like.

  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, most preferably 400,000 to One million. When the weight average molecular weight is smaller than 100,000, the adhesive force tends to be generated due to the reduced cohesive force of the pressure-sensitive adhesive layer. On the other hand, when the weight average molecular weight exceeds 5,000,000, the fluidity of the polymer is lowered, the wettability to the adherend (for example, polarizing plate) becomes insufficient, and the adherend and the adhesive layer of the adhesive sheet There is a tendency to cause blisters that occur in between. In addition, a weight average molecular weight means what was obtained by measuring by GPC (gel permeation chromatography).

  The glass transition temperature (Tg) of the (meth) acrylic polymer is preferably 0 ° C. or lower, more preferably −10 ° C. or lower, and further preferably −30 ° C. or lower (usually −100 ° C. or higher). When the glass transition temperature is higher than 0 ° C., the (meth) acrylic polymer does not flow easily, and, for example, the adherend (for example, a polarizing plate) is insufficiently wetted. It tends to cause blisters that occur between the layers. In particular, by setting the glass transition temperature to −61 ° C. or less, an adhesive layer excellent in wettability to the adherend and light peelability can be easily obtained. In addition, the glass transition temperature of a (meth) acrylic-type polymer can be adjusted in the said range by changing the monomer component and composition ratio to be used suitably.

<Antistatic component>
The pressure-sensitive adhesive composition of the present invention contains an organic salt having a melting point of 150 ° C. or less and / or an alkali metal salt. By containing an organic salt and / or an alkali metal salt having the melting point of 150 ° C. or less, which is an antistatic component (antistatic agent), excellent peeling antistatic properties can be imparted. In addition, the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition containing the antistatic component as described above can prevent antistatic to an adherend (for example, a polarizing plate) that is not antistatic when peeled. In addition, the pressure-sensitive adhesive sheet can be reduced in the contamination of the adherend. For this reason, it becomes very useful as a surface protection film in the technical field related to optical and electronic components in which charging and contamination are particularly serious problems.

  In addition, although the details of the reason why excellent antistatic properties are obtained by using an organic salt having a melting point of 150 ° C. or lower as the antistatic component (antistatic agent) are not clear, the melting point is 150 ° C. or lower. This organic salt has a low melting point (melting point of 150 ° C. or lower) compared with a normal antistatic component, and therefore it is considered that molecular movement is easy and excellent antistatic ability can be obtained. In particular, when antistatic is applied to the adherend, the organic salt having a melting point of 150 ° C. or less is transferred to the adherend in an extremely small amount, thereby achieving excellent peeling antistatic properties on the adherend. it is conceivable that. In particular, the melting point of the organic salt is preferably 100 ° C. or lower, more preferably 80 ° C. or lower, and most preferably room temperature (25 ° C.) or lower (for example, an ionic liquid). By using such an organic salt, transfer of the organic salt to the adherend can be performed more efficiently, and thus excellent peeling antistatic properties can be obtained.

  Further, the organic salt having a melting point of 150 ° C. or lower is liquid at any temperature of 150 ° C. or lower, so that it can be easily added and dispersed or dissolved in the pressure-sensitive adhesive as compared with a solid salt. Furthermore, when the organic salt having a melting point of 150 ° C. or lower is an ionic liquid, the ionic liquid has no vapor pressure (non-volatile), and therefore does not disappear over time, and the antistatic property of peeling can be continuously obtained. Have. The ionic liquid refers to a molten salt (ionic compound) having a melting point of 150 ° C. or lower and exhibiting a liquid state.

  The organic salt having a melting point of 150 ° C. or less is preferably 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. What consists of an organic cation component represented by Formula (A)-(E) and an anion component is used preferably. An organic salt having these cations provides a further excellent antistatic property for peeling.

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

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

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

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

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

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

  Specific examples include, for example, 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-hexyl. -3-methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1,1-dimethylpyrrolidinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidi Cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium Cation, 1-ethyl-1-propylpyrrolidini Cation, 1-ethyl-1-butylpyrrolidinium cation, 1-ethyl-1-pentylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation, 1-ethyl-1-heptylpyrrolidinium Cation, 1,1-dipropylpyrrolidinium cation, 1-propyl-1-butylpyrrolidinium cation, 1,1-dibutylpyrrolidinium cation, pyrrolidinium-2-one cation, 1-propylpiperidinium cation, 1-pentylpiperidinium cation, 1,1-dimethylpiperidinium cation, 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-butylpi Peridinium cation, 1-methyl-1-pentylpiperidinium cation 1-methyl-1-hexylpiperidinium cation, 1-methyl-1-heptylpiperidinium cation, 1-ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1 -Ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl-1-heptylpiperidinium cation, 1,1-dipropylpiperidinium cation, 1-propyl -1-butylpiperidinium cation, 1,1-dibutylpiperidinium cation, 2-methyl-1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, 1-ethylcarbazole Cations, N-ethyl-N-methylmorpholinium cations, etc. It is done.

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

  Specific examples include, for example, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, and 1-helium. Xyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazole Cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3 -Dimethylimidazolium cation, 1- (2-metho (Ciethyl) -3-methylimidazolium cation, 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium Cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium Cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium Cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium kathi Emissions, such as 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation.

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

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

  Examples of the cation represented by the formula (D) include a tetraalkylammonium cation, a trialkylsulfonium cation, a tetraalkylphosphonium cation, and a part of the alkyl group is substituted with an alkenyl group, an alkoxyl group, or an epoxy group. And so on.

  Specific examples include, for example, tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, tetraheptylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutyl Ethylsulfonium Kachi , Dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation, diallyldimethylammonium cation And tributyl- (2-methoxyethyl) phosphonium cation. Among them, asymmetric such as triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation, etc. Tetraalkylammonium cation, trialkylsulfonium cation, tetraalkylphosphonium cation, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, diallyldimethylammonium cation, N, N -Dimethyl-N-ethyl-N-propyla Monium cation, N, N-dimethyl-N-ethyl-N-butylammonium cation, N, N-dimethyl-N-ethyl-N-pentylammonium cation, N, N-dimethyl-N-ethyl-N-hexylammonium cation N, N-dimethyl-N-ethyl-N-heptylammonium cation, N, N-dimethyl-N-ethyl-N-nonylammonium cation, N, N-dimethyl-N, N-dipropylammonium cation, N, N-diethyl-N-propyl-N-butylammonium cation, N, N-dimethyl-N-propyl-N-pentylammonium cation, N, N-dimethyl-N-propyl-N-hexylammonium cation, N, N- Dimethyl-N-propyl-N-heptylammonium cation, N, N-di Tyl-N-butyl-N-hexylammonium cation, N, N-diethyl-N-butyl-N-heptylammonium cation, N, N-dimethyl-N-pentyl-N-hexylammonium cation, N, N-dimethyl- N, N-dihexylammonium cation, trimethylheptylammonium cation, N, N-diethyl-N-methyl-N-propylammonium cation, N, N-diethyl-N-methyl-N-pentylammonium cation, N, N-diethyl -N-methyl-N-heptylammonium cation, N, N-diethyl-N-propyl-N-pentylammonium cation, triethylpropylammonium cation, triethylpentylammonium cation, triethylheptylammonium cation, N, N- Dipropyl-N-methyl-N-ethylammonium cation, N, N-dipropyl-N-methyl-N-pentylammonium cation, N, N-dipropyl-N-butyl-N-hexylammonium cation, N, N-dipropyl- N, N-dihexylammonium cation, N, N-dibutyl-N-methyl-N-pentylammonium cation, N, N-dibutyl-N-methyl-N-hexylammonium cation, trioctylmethylammonium cation, N-methyl- N-ethyl-N-propyl-N-pentylammonium cation is preferably used.

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

On the other hand, the anion component is not particularly limited as long as it satisfies the fact that the melting point is an organic salt having a melting point of 150 ° C. or lower. For example, Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl _{7. ^{-, BF 4 -, PF 6}} -, SCN -, ClO 4 -, NO 3 -, CH 3 COO -, CF 3 COO -, CH 3 SO 3 -, CF 3 SO 3 -, C 4 F 9 SO 3 - , (CF ₃ SO ₂ ) ₂ N ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , (C ₃ F ₇ SO ₂ ) ₂ N ⁻ , (C ₄ F ₉ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , HF ₂ ⁻ , (CN) ₂ N ⁻ , C ₄ F ₉ SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) _{^{2 N -, C 3 F 7}} COO -, (CF 3 _{^{O 2) (CF 3 CO)}} N -, C 9 H 19 COO -, (CH 3) 2 PO 4 -, (C 2 H 5) 2 PO 4 -, C 2 H 5 OSO 3 -, C 6 H 13 _{^{OSO 3 -, C 8 H 17}} OSO 3 -, CH 3 (OC 2 H 4) 2 OSO 3 -, C 6 H 4 (CH 3) SO 3 -, (C 2 F 5) 3 PF 3 -, CH 3 CH (OH) COO ⁻ , (FSO ₂ ) ₂ N ^{— and the} like are used.

Moreover, as the anion component, an anion represented by the following formula (F) can also be used.

  As an anion component, an anion component containing a fluorine atom is particularly preferably used since an organic salt having a low melting point can be obtained.

Specific examples of the organic salt having a melting point of 150 ° C. or lower used in the present invention are appropriately selected from a combination of the cation component and the anion component. For example, 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium Hexafluorophosphate, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, 1-butyl-3- Methylpyridinium bis (pentafluoroethanesulfonyl) imide, 1-hexylpyridinium tetrafluoroborate, 1,1-dimethylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-ethyl Loridinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-butylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1- Pentylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-hexylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-heptylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-propylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-butylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-pentylpyrrolidinium (Trifluoromethanesulfonyl) imide, 1-ethyl-1-hexylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-heptylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1,1- Dipropylpyrrolidinium bis (triple olomethanesulfonyl) imide, 1-propyl-1-butylpyrrolidinium bis (trifluoromethanesulfonyl) imide, 1,1-dibutylpyrrolidinium bis (triple methanesulfonyl) imide, 1 -Propylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-pentylbiberidinium bis (trifluoromethanesulfonyl) imide, 1,1-dimethylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1 -Ethylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-propylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-butylpiperidinium bis (trifluoromethanesulfonyl) imide, -Methyl-1-pentylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-hexylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-methyl-1-heptylpiperidinium bis (trifluoromethane Sulfonyl) imide, 1-ethyl-1-propylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-butylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-pentylpiperi Nitrobis (trifluoromethanesulfonyl) imide, 1-ethyl-1-hexylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-ethyl-1-heptylpiperidinium bis (trifluoromethanesulfonyl) imide, 1,1- Dipropylpiperidinium bis (trifluoromethanesulfonyl) imide, 1-propyl-1-butylpiperidiniumpis (trifluoromethanesulfonyl) imide, 1,1-dibutylpiperidinium bis (trifluoromethanesulfonyl) imide, 1,1 -Dimethylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-ethylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-propylpyrrolidinium bis (pentafluoroethane) Sulfonyl) imide, 1-methyl-1-butylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-pentylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1- Xylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-heptylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-propylpyrrolidinium bis (pentafluoroethanesulfonyl) Imido, 1-ethyl-1-butylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-pentylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-hexylpyrrolidi Nibis (pentafluoroe Tansulfonyl) imide, 1-ethyl-1-heptylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dipropylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-propyl-1-butyl Pyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dibutylpyrrolidinium bis (pentafluoroethanesulfonyl) imide, 1-propylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-pentylpiperidinium Bis (Bentafluoroethanesulfonyl) imide, 1,1-dimethylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-ethylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1 - Pyrpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-butylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-pentylpiperidinium bis (pentafluoroethanesulfonyl) imide 1-methyl-1-hexylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-methyl-1-heptylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-propylpiperidi Nitrobis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-butylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-pentylpiperidinium bis (pentafluoroethanesulfonyl) imide, Ethyl-1- Xylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-1-heptylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dipropylpiperidinium bis (pentafluoroethanesulfonyl) imide 1-propyl-1-butylpiperidinium bis (pentafluoroethanesulfonyl) imide, 1,1-dibutylpiperidinium bis (pentafluoroethanesulfonyl) imide, 2-methyl-1-pyrroline tetrafluoroborate, 1- Ethyl-2-phenylindole tetrafluoroborate, 1,2-dimethylindole tetrafluoroborate, 1-ethylcarbazole tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3- Methyl imidazolium acetate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium heptafluorobutyrate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3 -Methylimidazolium perfluorobutane sulfonate, 1-ethyl-3-methylimidazolium dicyanamide, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium bis (pentafluoro) Ethanesulfonyl) imide, 1-ethyl-3-methylimidazolium tris (trifluoromethanesulfonyl) methide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methyl Midazolium hexafluorophosphate, 1-butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium heptafluorobutyrate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl -3-methylimidazolium perfluorobutanesulfonate, 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfate 1-octyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-2,3-dimethylimidazolium tetrafluoroborate, 1,2-dimethyl- 3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-methylpyrazolium tetrafluoroborate, 2-methylpyrazolium tetrafluoroporate, 1-ethyl-2,3,5-trimethylpyrazolium bis (trifluoro) Romethanesulfonyl) imide, 1-propyl-2,3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) imide, 1-butyl-2,3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) imide, 1 -Ethyl -2,3,5-trimethylpyrazolium bis (pentafluoroethanesulfonyl) imide, 1-propyl-2,3,5-trimethylpyrazolium bis (pentafluoroethanesulfonyl) imide, 1-butyl-2,3 , 5-trimethylpyrazolium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-2,3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) trifluoroacetamide, 1-propyl-2,3,5- Trimethylpyrazolium bis (trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl-2,3,5-trimethylpyrazolium bis (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-2,3,5-trimethylpyra Zolinium bis (trifluoromethane Sulfonyl) imide, 1-propyl-2,3,5-trimethylpyrazolinium bis (trifluoromethanesulfonyl) imide, 1-butyl-2,3,5-trimethylpyrazolinium bis (trifluoromethanesulfonyl) imide, 1- Ethyl-2,3,5-trimethylpyrazolinium bis (pentafluoroethanesulfonyl) imide, 1-propyl-2,3,5-trimethylpyrazolinium bis (pentafluoroethanesulfonyl) imide, 1-butyl-2, 3,5-trimethylpyrazolinium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-2,3,5-trimethylpyrazolinium bis (trifluoromethanesulfonyl) trifluoroacetamide, 1-propyl-2,3,5 -Trimethylpyrazolinium bis (trifluoro Methanesulfonyl) trifluoroacetamide, 1-butyl-2,3,5-trimethylpyrazolinium bis (trifluoromethanesulfonyl) trifluoroacetamide, tetrapentylammonium trifluoromethanesulfonate, tetrapentylammonium bis (trifluoromethanesulfonyl) imide, tetra Hexylammonium trifluoromethanesulfonate, tetrahexylammonium bis (trifluoromethanesulfonyl) imide, tetrahexylammonium trifluoromethanesulfonate, tetraheptylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, Diallyldimethyl Ammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium bis (pentafluoroethanesulfonyl) imide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium tetrafluoroborate, N, N-diethyl-
N-methyl-N- (2-methoxyethyl) ammonium trifluoromethanesulfonate, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl- N-methyl-N- (2-methoxyethyl) ammonium bis (pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium trifluoromethanesulfonate, glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, glycidyltrimethylammonium bis (pentafluoroethanesulfonyl) imide Tetraoctylphosphonium trifluoromethanesulfonate, tetraoctylphosphonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl -N-ethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N -Pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-heptylammonium bis ( Trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-nonylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N, N-dipropylammonium bis (trifluoromethanesulfonyl) imide, N , N- Dimethyl-N-propyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl- N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-hexylammonium bis ( Trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-pentyl-N-hexylammonium bis (trifluoromethane) Sulfonyl) imide, N, N-dimethyl-N, N-dihexylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-propylammonium bis (Trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide N, N-diethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, triethylpropylammonium bis (trifluoromethanesulfonyl) imide, triethylpe Tylammonium bis (trifluoromethanesulfonyl) imide, triethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-methyl-N-ethylammonium bis (trifluoromedansulfonyl) imide, N, N-dipropyl- N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N, N-dihexyl Ammonium bis (trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-hexyl Ammonium bis (trifluoromethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) imide, N-methyl-N-ethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, 1-butylpyridinium ( Trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-3-methylimidazolium (trifluoromethanesulfonyl) trifluoroacetamide, N-ethyl-N-methyl Examples thereof include morpholinium thiocyanate and 4-ethyl-4-methylmorpholinium methyl carbonate.

  A commercially available organic salt having a melting point of 150 ° C. or lower may be used, but it can also be synthesized as follows. The method for synthesizing the organic salt having a melting point of 150 ° C. or lower is not particularly limited as long as the desired organic salt is obtained. In general, the document “ionic liquids—the forefront and future of development” [(stock The halide method, the hydroxide method, the acid ester method, the complex formation method, the neutralization method, etc. are used as described in “

  The synthesis method of the halide method, hydroxide method, acid ester method, complex formation method, and neutralization method will be described below using a nitrogen-containing onium salt as an example. Other sulfur-containing onium salts, phosphorus-containing onium salts, etc. The organic salt (for example, ionic liquid) having a melting point of 150 ° C. or lower can be obtained by the same method.

The halide method is a method carried out by reactions as shown in the following formulas (1) to (3). First, a tertiary amine and an alkyl halide are reacted to obtain a halide. (Reaction Formula (1), chlorine, bromine and iodine are used as halogens) Acid (HA) or salt (MA, M is an organic salt anion structure (A ⁻ ) for the obtained halide. A target organic salt (R ₄ NA) is obtained by reacting with a target anion such as ammonium, lithium, sodium, potassium and the like to form a salt.

The hydroxide method is a method performed by reactions as shown in (4) to (8). First, halide (R ₄ NX) is subjected to ion exchange membrane electrolysis (reaction formula (4)), OH type ion exchange resin method (reaction formula (5)) or reaction with silver oxide (Ag ₂ O) (reaction formula ( 6)) to obtain the hydroxide (R ₄ NOH). (Chlorine, bromine, and iodine are used as the halogen.) The obtained hydroxide is converted into the desired organic salt (R ₄ NA) using the reactions of the reaction formulas (7) to (8) in the same manner as the halogenation method. ) Is obtained.

The acid ester method is a method performed by reactions as shown in (9) to (11). First, a tertiary amine (R ₃ N) is reacted with an acid ester to obtain an acid ester product. (Reaction formula (9), as the acid ester, an ester of an inorganic acid such as sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid or carbonic acid, or an organic acid such as methanesulfonic acid, methylphosphonic acid or formic acid) The target organic salt (R ₄ NA) is obtained from the resulting acid ester using the reactions of the reaction formulas (10) to (11) in the same manner as in the halogenation method. Further, by using methyl trifluoromethanesulfonate, methyl trifluoroacetate or the like as the acid ester, an organic salt can be directly obtained.

The complex formation method is a method performed by reactions as shown in (12) to (15). First, a quaternary ammonium halide (R ₄ NX), a quaternary ammonium hydroxide (R ₄ NOH), a quaternary ammonium carbonate ester (R ₄ NOCO ₂ CH ₃ ) or the like is added to hydrogen fluoride (HF) or Reaction with ammonium fluoride (NH ₄ F) gives a quaternary ammonium fluoride salt. (Reaction formulas (12) to (14)) The obtained quaternary ammonium fluoride salt is subjected to complex formation reaction with fluorides such as BF ₃ , AlF ₃ , PF ₅ , AsF ₅ , SbF ₅ , NbF ₅ , TaF _5. Organic salts can be obtained. (Reaction Formula (15))

The neutralization method is a method performed by a reaction as shown in (16). Tertiary amine and HBF ₄ , HPF ₆ , CH ₃ COOH, CF ₃ COOH, CF ₃ SO ₃ H, (CF ₃ SO ₂ ) ₂ NH, (CF ₃ SO ₂ ) ₃ CH, (C ₂ F ₅ SO ₂ ) ₂ It can be obtained by reacting with an organic acid such as NH.

  R in the formulas (1) to (16) represents hydrogen or a hydrocarbon group having 1 to 20 carbon atoms, and a part of the hydrocarbon group may be a functional group substituted with a hetero atom. Good.

  In addition, the said organic salt may be used independently, and 2 or more types may be mixed and used for it.

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

  The content of the organic salt or the like (organic salt having a melting point of 150 ° C. or less and / or alkali metal salt) is preferably 4.9 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic polymer. 0.001-2.5 mass parts is more preferable, More preferably, it is 0.05-1 mass part, Most preferably, it is 0.1-0.5 mass part. Within the above range, peeling antistatic properties and low contamination are easily achieved, which is preferable.

<Alkylene oxide group-containing compound containing no organopolysiloxane having a number average molecular weight of 10,000 or less>
The pressure-sensitive adhesive composition of the present invention further contains an alkylene oxide group-containing compound not containing an organopolysiloxane having a number average molecular weight of 10,000 or less (hereinafter sometimes simply referred to as “alkylene oxide group-containing compound”). It is preferable that By containing the alkylene oxide group-containing compound in the pressure-sensitive adhesive, a pressure-sensitive adhesive having excellent wettability to the adherend can be obtained. In addition, the pressure-sensitive adhesive sheet (surface protective film) formed from the pressure-sensitive adhesive composition containing the alkylene oxide group-containing compound can transfer a small amount of the alkylene oxide group-containing compound to an adherend, Improve the wettability of the adherend surface, and in the process after peeling of the pressure-sensitive adhesive sheet (surface protective film), when applying a pressure-sensitive adhesive or adhesive to the adherend, it becomes easy to spread evenly, When the pressure-sensitive adhesive sheet is bonded, it becomes possible to easily develop good pressure-sensitive adhesiveness (adhesiveness), which is useful.

  Specific examples of the alkylene oxide group-containing compound include, for example, polyoxyalkylene alkylamine, polyoxyalkylene diamine, polyoxyalkylene fatty acid ester, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene alkyl phenyl ether, polyoxyalkylene alkyl ether , Nonionic surfactants such as polyoxyalkylene alkyl allyl ether and polyoxyalkylene alkyl phenyl allyl ether; polyoxyalkylene alkyl ether sulfate ester salt, polyoxyalkylene alkyl ether phosphate ester salt, polyoxyalkylene alkyl phenyl ether sulfate Anionic surfactants such as ester salts and polyoxyalkylene alkylphenyl ether phosphate esters In addition, a cationic surfactant having a polyoxyalkylene chain (polyalkylene oxide chain) or an amphoteric surfactant, a polyether compound having a polyoxyalkylene chain (and derivatives thereof), or having a polyoxyalkylene chain Examples include acrylic compounds (and their derivatives), ester compounds having a polyoxyalkylene chain (and their derivatives), and the like. Moreover, you may mix | blend a polyoxyalkylene chain containing monomer with an acrylic polymer as said alkylene oxide group containing compound. The said alkylene oxide group containing compound may be used individually and may be used in combination of 2 or more type.

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

  Specific examples of the acrylic compound having a polyoxyalkylene chain include a (meth) acrylate polymer having an oxyalkylene group. As the oxyalkylene group, the added mole number of the oxyalkylene unit is preferably 1 to 50, more preferably 2 to 30, and still more preferably 2 to 20 from the viewpoint of coordination of an organic salt or the like. The terminal of the oxyalkylene chain 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, and specific examples of the (meth) acrylic acid alkylene oxide include ethylene. Examples of the glycol group-containing (meth) acrylate include methoxypolyethylene glycol (meth) acrylate types such as methoxydiethylene glycol (meth) acrylate and methoxytriethylene glycol (meth) acrylate, ethoxydiethylene glycol (meth) acrylate, ethoxytriethylene glycol ( Ethoxypolyethylene glycol (meth) acrylate type such as (meth) acrylate, butoxy-diethylene glycol (meth) acrylate, butoxy-triethyl Butoxy-polyethylene glycol (meth) acrylate types such as N-glycol (meth) acrylate, Phenoxy-polyethylene glycol (meth) acrylate types such as phenoxy-diethylene glycol (meth) acrylate, phenoxy-triethylene glycol (meth) acrylate, 2-ethylhexyl -Polyethylene glycol (meth) acrylate, nonylphenol-polyethylene glycol (meth) acrylate type, methoxypolypropylene glycol (meth) acrylate type such as methoxydipropylene glycol (meth) acrylate, and the like.

  Moreover, other monomer components other than the (meth) acrylic acid alkylene oxide can also be used as the monomer component. Specific examples of other monomer components include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, and isobutyl (meth) acrylate. , Hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate , 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.

  Furthermore, as other monomer components other than the (meth) acrylic acid alkylene oxide, carboxyl group-containing (meth) acrylate, phosphoric acid group-containing (meth) acrylate, cyano group-containing (meth) acrylate, vinyl esters, aromatic vinyl compounds , Acid anhydride group-containing (meth) acrylate, hydroxyl group-containing (meth) acrylate, amide group-containing (meth) acrylate, amino group-containing (meth) acrylate, epoxy group-containing (meth) acrylate, N-acryloylmorpholine, vinyl ethers Etc. can be used as appropriate.

  Specific examples of the ester compound having a polyoxyalkylene chain include diethylene glycol di-2-ethyl hexonate, tetraethylene glycol di-2-ethyl hexonate, polyethylene glycol di-2-ethyl hexonate, and triethylene. Glycol diethyl butyrate, polyethylene glycol diethyl butyrate, polypropylene glycol diethyl hexonate, triethylene glycol dibenzoate, tetraethylene glycol dibenzoate, polyethylene glycol dibenzoate, polypropylene glycol dibenzoate, or polyethylene glycol-2-ethyl Examples include xonate benzoate.

  As a more preferred embodiment, the alkylene oxide group-containing compound not containing the organopolysiloxane is a compound having a (poly) ethylene oxide chain at least partially. By blending the (poly) ethylene oxide chain-containing compound, the compatibility between the base polymer and the antistatic component is improved, bleeding to the adherend is suitably suppressed, and a low-staining adhesive composition is obtained. It is done. In particular, when a PPG-PEG-PPG block copolymer is used, a pressure-sensitive adhesive excellent in low contamination can be obtained. As said (poly) ethylene oxide chain containing compound, it is preferable that the weight of the (poly) ethylene oxide chain to the whole alkylene oxide group containing compound which does not contain the said organopolysiloxane is 5 to 90 mass%, More preferably, it is 5 to 5 mass%. It is 85 mass%, More preferably, it is 5-80 mass%, Most preferably, it is 5-75 mass%.

  As a molecular weight of the alkylene oxide group-containing compound not containing the organopolysiloxane, the number average molecular weight (Mn) is preferably 10,000 or less, more preferably 100 to 5,000, and still more preferably 400 to 3,000. When Mn is larger than 10,000, the compatibility with the (meth) acrylic polymer is lowered, and the pressure-sensitive adhesive layer tends to be whitened. When Mn is smaller than 100, contamination with the alkylene oxide group-containing compound may easily occur. In addition, Mn means the value of polystyrene conversion obtained by GPC (gel permeation chromatography) here.

  In addition, specific examples of commercially available alkylene oxide group-containing compounds that do not contain the organopolysiloxane include, for example, Adekapluronic 17R-4, Adekapluronic 25R-2 (all of which are manufactured by ADEKA), Emulgen 120 (Kao) Etc.).

  As a compounding quantity of the alkylene oxide group containing compound which does not contain the said organopolysiloxane, it can be set as 0.005-20 mass parts with respect to 100 mass parts of (meth) acrylic-type polymers, Preferably it is 0.01. -10 parts by mass, more preferably 0.05-5 parts by mass, and most preferably 0.1-1 part by mass. If the amount is too small, the effect of preventing bleeding of the antistatic component is reduced, and if it is too large, contamination with the alkylene oxide group-containing compound tends to occur, such being undesirable.

<Organopolysiloxane having an oxyalkylene chain>
The pressure-sensitive adhesive composition of the present invention can contain an organopolysiloxane having an oxyalkylene chain, and more preferably contains an organopolysiloxane having an oxyalkylene main chain. By using the organopolysiloxane, the surface free energy on the surface of the pressure-sensitive adhesive is reduced, and it is presumed that both low contamination and light release can be achieved even with a small content.

As the organopolysiloxane, a known organopolysiloxane having a polyoxyalkylene main chain can be used as appropriate, and is preferably represented by the following formula.

(Wherein R ₁ and / or R ₂ has an oxyalkylene chain having 1 to 6 carbon atoms, and the alkylene group in the oxyalkylene chain may be linear or branched, and the oxyalkylene chain) The terminal of may be an alkoxy group or a hydroxyl group, and either R ₁ or R ₂ may be a hydroxyl group, or may be an alkyl group or an alkoxy group. And a functional group in which a part of the group or alkoxy group is substituted with a hetero atom may be used, and n is an integer of 1 to 300.)

  The organopolysiloxane has a siloxane-containing site (siloxane site) as the main chain and an oxyalkylene chain bonded to the end of the main chain. By using the organosiloxane having an oxyalkylene chain, a compatibility balance with a (meth) acrylic polymer and an organic salt (an organic salt having a melting point of 150 ° C. or less and / or an alkali metal salt) is obtained, It is presumed that light release has been achieved.

Moreover, as said organopolysiloxane in this invention, the following structures can be used, for example. Specifically, R ₁ and / or R ₂ in the formula has an oxyalkylene chain containing a hydrocarbon group having 1 to 6 carbon atoms, and as the oxyalkylene chain, an oxymethylene group, an oxyethylene group, an oxy Examples thereof include a propylene group and an oxybutylene group, and among them, an oxyethylene group and an oxypropylene group are preferable. In addition, when both R ₁ and R ₂ have an oxyalkylene chain, they may be the same or different.

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

  Furthermore, the end of the oxyalkylene chain may be an alkoxy group or a hydroxyl group, but more preferably an alkoxy group. When a separator is attached to the surface of an adhesive layer to protect the adhesive surface, an organopolysiloxane having a hydroxyl group at the end causes an interaction with the separator, and adhesion (peeling) occurs when the separator is removed from the surface of the adhesive layer. The power may increase.

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

  Specific examples of the organopolysiloxane having an oxyalkylene chain include, for example, commercially available products having trade names of X-22-4952, X-22-4272, X-22-6266, KF-6004, KF-889. (Shin-Etsu Chemical Co., Ltd.), BY16-201, SF8427 (Toray Dow Corning, Inc.), IM22 (Asahi Kasei Wacker Co., Ltd.) and the like. These compounds may be used alone or in combination of two or more.

In addition to the organosiloxane having (bonding) the oxyalkylene chain in the main chain, it is also possible to use an organosiloxane having (bonding) the oxyalkylene chain in the side chain. The use of an organosiloxane having an alkylene chain is a more preferred embodiment. As the organopolysiloxane, an organopolysiloxane having a known polyoxyalkylene side chain can be used as appropriate, and is preferably represented by the following formula.

Wherein R ₁ is a monovalent organic group, R ₂ , R ₃ and R ₄ are alkylene groups, R ₅ is hydrogen or an organic group, and m and n are integers from 0 to 1000, provided that m and n are simultaneously (A and b are integers from 0 to 100, provided that a and b are not 0 at the same time.)

Moreover, as said organopolysiloxane in this invention, the following structures can be used, for example. Specifically, R ₁ in the formula is a monovalent group exemplified by an alkyl group such as a methyl group, an ethyl group or a propyl group, an aryl group such as a phenyl group or a tolyl group, or an alkyl group such as a benzyl group or a phenethyl group. It is an organic group, and each may have a substituent such as a hydroxyl group. R ₂ , R ₃ and R ₄ may be an alkylene group having 1 to 8 carbon atoms such as a methylene group, an ethylene group or a propylene group. Here, R ₃ and R ₄ are different alkylene groups, and R ₂ may be the same as or different from R ₃ or R ₄ . R ₃ and R ₄ are either one for increasing the concentration of an organic salt or the like (an organic salt having a melting point of 150 ° C. or lower and / or an alkali metal salt) that can be dissolved in the polyoxyalkylene side chain, An ethylene group or a propylene group is preferred. R ₅ may be an alkyl group such as a methyl group, an ethyl group or a propyl group, or a monovalent organic group exemplified by an acyl group such as an acetyl group or a propionyl group, each having a substituent such as a hydroxyl group. It may be. These compounds may be used alone or in combination of two or more. Moreover, you may have reactive substituents, such as a (meth) acryloyl group, an allyl group, and a hydroxyl group, in a molecule | numerator. Among the organosiloxanes having a polyoxyalkylene side chain, an organosiloxane having a polyoxyalkylene side chain having a hydroxyl group terminal is presumed to have a good balance of compatibility.

  Specific examples of the organosiloxane include, for example, commercial names 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 (Shin-Etsu Chemical) 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), TSF-44 0, TSF-4441, TSF-4445, TSF-4450, TSF-4446, TSF-4442, TSF-4460 (manufactured by Momentive Performance Materials), BYK-333, BYK-307, BYK-377, BYK-UV3500, BYK-UV3570 (manufactured by Big Chemie Japan) can be used. These compounds may be used alone or in combination of two or more.

  The organosiloxane 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.

  Moreover, 0.01-5 mass parts is preferable with respect to 100 mass parts of said (meth) acrylic-type polymers, More preferably, it is 0.05-3 mass parts, More preferably, it is. Is 0.1 to 1 part by mass. It is preferable for it to be in the above-mentioned range, since it is easy to achieve both peel antistatic properties and light peelability (removability).

<Crosslinking agent>
The pressure-sensitive adhesive composition of the present invention preferably contains a crosslinking agent. In this invention, an adhesive layer can be formed by bridge | crosslinking using the crosslinking agent contained in 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. Thus, a pressure-sensitive adhesive layer (pressure-sensitive adhesive sheet) having more excellent 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), dimer diisocyanate, cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate. Aliphatic isocyanates such as (IPDI), aromatic isocyanates such as 2,4-tolylene diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate (XDI), allophanate bonds, biuret bonds, isocyanates Nurate 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 in combination of two or more.

  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, and 0.1 to 8 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer. It is more preferably contained, more preferably 0.5 to 5 parts by mass, and most preferably 1.0 to 2.5 parts by mass. When the content is less than 0.01 parts by mass, the crosslinking formation by the crosslinking agent 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. These crosslinking agents may be used alone or in combination of two or more.

  Moreover, it can also add as a polyfunctional monomer which has 2 or more of radiation reactive unsaturated bonds as a substantial crosslinking agent, and can also be bridge | crosslinked with a radiation. The polyfunctional monomer includes two or more radiation-reactive unsaturated bonds such as vinyl group, acryloyl group, methacryloyl group, and vinylbenzyl group that can be crosslinked (cured) by irradiation with radiation. The polyfunctional monomer component is used. In general, those having 10 or less radiation-reactive unsaturated bonds are preferably used. Moreover, a polyfunctional monomer may be used independently and may be used in mixture of 2 or more types.

  Specific examples of the polyfunctional monomer include, for example, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and 1,6- Xanthdiol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, divinylbenzene, N, N′-methylenebisacrylamide and the like.

  The content of the polyfunctional monomer used in the present invention is appropriately selected depending on the balance with the (meth) acrylic polymer to be crosslinked and further depending on the intended use as an adhesive sheet. In order to obtain sufficient heat resistance due to the cohesive force of the pressure-sensitive adhesive layer, generally, it is preferably contained in an amount of 0.1 to 30 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer. . Moreover, it is more preferable to mix | blend at 10 mass parts or less with respect to 100 mass parts of (meth) acrylic-type polymers from the point of a softness | flexibility and adhesiveness.

  Examples of the radiation include ultraviolet rays, laser rays, α rays, β rays, γ rays, X rays, electron rays, etc., but ultraviolet rays are preferable from the viewpoints of controllability, ease of handling, and cost. Used. More preferably, ultraviolet rays having a wavelength of 200 to 400 nm are used. Ultraviolet rays can be irradiated using an appropriate light source such as a high-pressure mercury lamp, a microwave excitation lamp, or a chemical lamp. In addition, when using an ultraviolet-ray as a radiation, a photoinitiator is added to an adhesive composition.

In the case of adding the photopolymerization initiator, the pressure-sensitive adhesive composition is applied directly on the adherend, or after being applied to one or both sides of the support, and then irradiated with light to form a pressure-sensitive adhesive layer. Can be obtained. Usually, the pressure-sensitive adhesive layer is obtained by irradiating ultraviolet rays having an illuminance of 1 to 200 mW / cm ² at a wavelength of 300 to 400 nm and photopolymerizing them with a light amount of about 200 to 4000 mJ / cm ² .

  The photopolymerization initiator may be any substance that generates radicals or cations by irradiating ultraviolet rays having an appropriate wavelength that can trigger the polymerization reaction according to the type of the radiation-reactive component.

  Examples of radical photopolymerization initiators include benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, o-benzoylbenzoic acid methyl-p-benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, benzyldimethyl ketal, trichloro Acetophenones such as acetophenone, 2,2-diethoxyacetophenone and 1-hydroxycyclohexyl phenyl ketone, pros such as 2-hydroxy-2-methylpropiophenone and 2-hydroxy-4′-isopropyl-2-methylpropiophenone Benzophenones such as piophenones, benzophenone, methylbenzophenone, p-chlorobenzophenone, p-dimethylaminobenzophenone, 2-chlorothioxanthone, 2- Thioxanthones such as tilthioxanthone and 2-isopropylthioxanthone, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyl) Examples include acylphosphine oxides such as-(ethoxy) -phenylphosphine oxide, benzyl, dibenzosuberone, and α-acyloxime ester.

  Examples of the cationic photopolymerization initiator include onium salts such as aromatic diazonium salts, aromatic iodonium salts, and aromatic sulfonium salts, and organometallic complexes such as iron-allene complexes, titanocene complexes, and arylsilanol-aluminum complexes, Examples thereof include nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenol sulfonic acid ester, diazonaphthoquinone, and N-hydroxyimide sulfonate. The photopolymerization initiators may be used alone or in combination of two or more.

  It is preferable to contain 0.1-10 mass parts normally with respect to 100 mass parts of (meth) acrylic-type polymers, The said photoinitiator has more preferably 0.2-7 mass parts.

  It is also possible to use a photoinitiated polymerization aid such as amines in combination. Examples of the photoinitiator include 2-dimethylaminoethyl benzoate, dimethylaminoacetophenone, p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ester, and the like. The photopolymerization initiation assistant may be used alone or in combination of two or more. The polymerization initiation assistant is preferably 0.05 to 10 parts by mass, and more preferably 0.1 to 7 parts by mass with respect to 100 parts by mass of the (meth) acrylic polymer.

  The pressure-sensitive adhesive composition may further contain a cross-linking catalyst for causing any of the above-described cross-linking reactions to proceed more effectively. Examples of such crosslinking catalysts include tin catalysts such as dibutyltin dilaurate and dioctyltin dilaurate, tris (acetylacetonato) iron, tris (hexane-2,4-dionato) iron, and 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-1,3) Diato), 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 propionyl acetate) iron, tris (propionyl acetate ethyl) iron, tris (propionyl acetate-n-propyl) iron, Tris (propionyl acetate isopropyl) iron, Tris (propionyl acetate-n-butyl) iron, Tris (propionyl acetate-sec-butyl) iron, Tris (propionyl acetate-tert-butyl) iron, Tris (benzyl acetoacetate) iron, Tris (Dimethyl malonate) iron, tris (diethyl malonate) iron, trimethoxy iron, Iron-based catalysts such as reethoxy 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 (amount of use) of the crosslinking catalyst is not particularly limited. For example, the content is preferably 0.0001 to 1 part by mass with respect to 100 parts by mass of the (meth) acrylic polymer. More preferably, 0.5 parts by mass is contained. Within the above range, when the pressure-sensitive adhesive layer is formed, the speed of the cross-linking reaction is high, and the pot life of the pressure-sensitive adhesive composition is lengthened.

  The pressure-sensitive adhesive composition is further crosslinked in order to suppress an excessive increase in viscosity or gelation of the pressure-sensitive adhesive composition after blending any of the above-mentioned crosslinking agents, and to extend the pot life of the pressure-sensitive adhesive composition. A retarder can be included. Examples of the crosslinking retarder include β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, stearyl acetoacetate, acetylacetone, 2,4-hexanedione, benzoylacetone and the like. Ketoenol tautomers such as β-diketones. In particular, acetylacetone or ethyl acetoacetate is preferably used as a crosslinking retarder. As content of the said crosslinking retarder, it is preferable to contain 1-30 mass parts with respect to 100 mass parts of said (meth) acrylic-type polymers.

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

<Adhesive layer / adhesive sheet>

  The pressure-sensitive adhesive sheet of the present invention is preferably formed by forming a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition on one side or both sides of a support. The pressure-sensitive adhesive sheet disclosed herein is generally in a form referred to as a pressure-sensitive adhesive tape, pressure-sensitive adhesive label, pressure-sensitive adhesive film, etc., and particularly used as an optical component (for example, a liquid crystal display panel component such as a polarizing plate or a wave plate). It is suitable as a surface protective film for protecting the surface of the optical component during processing or transport of the optical 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.

  The pressure-sensitive adhesive sheet of the present invention is preferably formed by forming the pressure-sensitive adhesive layer on a support (base material). In this case, crosslinking of the pressure-sensitive adhesive composition is performed after application of the pressure-sensitive adhesive composition. Generally, it is also possible to transfer a pressure-sensitive adhesive layer made of a pressure-sensitive adhesive composition after crosslinking to a support or the like.

  The method for forming the pressure-sensitive adhesive layer on the support is not particularly limited. For example, the pressure-sensitive adhesive composition (solution) is applied to the support, and the polymerization solvent is removed by drying to support the pressure-sensitive adhesive layer. It is produced by forming on top. Thereafter, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction. Further, when the pressure-sensitive adhesive composition is applied on a support to produce 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. You may add to.

  Moreover, as a formation method of the adhesive layer at the time of manufacturing the adhesive sheet (surface protective film) of this invention, the well-known method used for manufacture of adhesive tapes 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 pressure-sensitive adhesive layer has a thickness of 3 to 100 μm, preferably about 5 to 50 μm. It is preferable for the thickness of the pressure-sensitive adhesive layer to be in the above-mentioned range since it is easy to obtain an appropriate balance between removability and pressure-sensitive adhesiveness.

  Moreover, it is preferable that the total thickness of the adhesive sheet of this invention is 1-400 micrometers, It is more preferable that it is 10-200 micrometers, It is most preferable that it is 20-100 micrometers. Within the above range, it is excellent in adhesive properties (removability, adhesiveness, etc.), workability, and appearance properties, and is a preferred embodiment. In addition, the said total thickness means the sum total of the thickness containing all these layers, when it has a support body, an adhesive layer, other antistatic layers, etc.

<Support>
In the technology disclosed herein, the resin material constituting the support (base material) can be used without particular limitation. For example, transparency, mechanical strength, thermal stability, moisture shielding property, isotropic It is preferable to use a material excellent in properties such as property, flexibility and dimensional stability. In particular, since the support has flexibility, the pressure-sensitive adhesive composition can be applied by a roll coater or the like, and can be wound into a roll shape, which is useful.

  Examples of the support 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; polymethyl methacrylate, and the like. A plastic film composed of a resin material having an acrylic polymer as a main resin component (a main component of the resin component, typically a component occupying 50% by mass or more) is preferably used as the support. it can. 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. The support may be composed of a blend of two or more of the above-described polymers.

  As the support, 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 for a pressure-sensitive adhesive sheet (surface protective film), such as excellent optical characteristics and dimensional stability, and has the property of being easily charged as it is.

  Various additives such as antioxidants, ultraviolet absorbers, plasticizers, colorants (pigments, dyes, etc.) may be blended in the resin material constituting the support, if necessary. Further, the surface of the support may be subjected to known or conventional surface treatments such as corona discharge treatment, plasma treatment, ultraviolet irradiation treatment, acid treatment, alkali treatment, and application of a primer. Such a surface treatment can be, for example, a treatment for improving the adhesion between the support and the pressure-sensitive adhesive layer (others, in some cases, an antistatic layer or the like) (the anchoring property of the pressure-sensitive adhesive layer). A surface treatment in which a polar group such as a hydroxyl group is introduced on the surface of the support can be preferably employed.

  Moreover, the adhesive sheet of this invention may have an antistatic layer in the surface on the opposite side to the adhesive layer side on a support body. Furthermore, it is also possible to use a plastic film subjected to antistatic treatment as the support. Use of the support is preferable because charging of the pressure-sensitive adhesive sheet (surface protective film) itself when peeled is suppressed.

  Further, by subjecting the support to an antistatic treatment, it is possible to reduce the charge of the pressure-sensitive adhesive sheet itself and to have excellent antistatic properties against peeling to the adherend. In addition, there is no restriction | limiting in particular as a method to provide peeling antistatic property, 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 containing, a method of depositing or plating a conductive material, a method of kneading an antistatic agent, and the like.

<Separator>
In the pressure-sensitive adhesive sheet 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 optical member of the present invention is preferably formed by bonding the pressure-sensitive adhesive sheet. Since the pressure-sensitive adhesive sheet is excellent in shearing force at the time of low-speed peeling, curling of the adherend (optical member) to which the pressure-sensitive adhesive sheet is bonded can be suppressed (curl adjustability), excellent in handleability, Since it is excellent in peeling antistatic property, it can be used for surface protection applications (surface protective film) during processing, transportation, shipping, etc., and is useful for protecting the surface of the optical member (polarizing plate, etc.). In particular, since it can be used for plastic products and the like that are likely to generate static electricity, it is very useful for antistatic applications in the technical fields related to optical and electronic parts where charging is a particularly serious problem.

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

  Each characteristic in the following description was measured or evaluated as follows.

<Measurement of weight average molecular weight (Mw) of (meth) acrylic polymer>
The weight average molecular weight (Mw) was 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)
The weight average molecular weight was determined in terms of polystyrene.

<Glass transition temperature (Tg) of (meth) acrylic polymer>
The glass transition temperature Tg (° C.) was determined by the following formula (17) using the following literature value as the glass transition temperature Tgn (° C.) of the homopolymer of each monomer.

Formula (17): 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
N, N-diethylacrylamide (DEAA): 81 ° C.
N, N-dimethylacrylamide (DMAA): 119 ° C
Acryloylmorpholine (ACMO): 145 ° C
Acrylic acid (AA): 106 ° C
Ethoxydiethylene glycol acrylate (EDE): -70 ° 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), “Polymer Handbook” (John Wiley & Sons), and monomer manufacturer maker's Kadalog values were referred to.

  Moreover, about the glass transition temperature (Tg) (degreeC) of the (meth) acrylic-type polymer obtained with the monomer whose document value is unknown, it determined by the dynamic viscoelasticity measurement in the following procedure.

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

<Measurement of peeling voltage>
After the pressure-sensitive adhesive sheet 1 according to Examples and the like was cut to a size of 70 mm in width and 130 mm in length and the release liner was peeled off, as shown in FIG. 1, the acrylic plate 10 (Mitsubishi Rayon Co., Ltd. On the surface of the polarizing plate 20 (manufactured by Nitto Denko Corporation, SEG1423DU polarizing plate, width: 70 mm, length: 100 mm) bonded to the product name “Acrylite”, thickness: 1 mm, width: 70 mm, length: 100 mm, The pressure-sensitive adhesive sheet 1 was crimped by a hand roller so that one end of the pressure-sensitive adhesive sheet 1 protruded 30 mm from the end of the polarizing plate 20.
The sample was left in an environment of 23 ° C. × 50% RH for one day, and then set at a predetermined position on a sample fixing base 30 having a height of 20 mm. The edge part of the pressure-sensitive adhesive sheet 1 protruding 30 mm from the polarizing plate 20 was fixed to an automatic winder (not shown), and peeled so that the peeling angle was 150 ° and the peeling speed was 10 m / min. The potential measuring device 40 (model “KSD-0103” manufactured by Kasuga Denki Co., Ltd.) in which the potential of the adherend (polarizing plate) surface generated at this time is fixed at a position 100 mm in height from the center of the polarizing plate 20. The peeling voltage was measured. The measurement was performed in an environment of 23 ° C. and 50% RH. Note that the peeling band voltage contributes to peeling antistatic properties.

  The peeling voltage (kV) (absolute value) in the present invention is preferably 0.8 or less, more preferably 0.7 or less, and still more preferably 0.5 or less. Within the above range, the pressure-sensitive adhesive sheet after peeling is not charged, and is excellent in peeling antistatic property and workability.

<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. Made by SEG1423DU polarizing plate, width: 25 mm, length: 100 mm, and left at room temperature (23 ° C. × 50% RH) for 30 minutes, and then left at a peeling speed of 0.06 mm / min (low speed peeling) and sheared. The maximum load (N / cm ² ) at that time was taken as the shear force.

In addition, the said shear force (N / cm < ² >) is 10 or more, Preferably, it is 10-40, More preferably, it is 10-30. 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.

  Moreover, the preparation method of the (meth) acrylic-type polymer, the adhesive composition (acrylic adhesive solution), and the adhesive sheet (surface protection film) was described below.

[Example 1]
<Preparation of (meth) acrylic polymer>
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a condenser, 94 parts by mass of 2-ethylhexyl acrylate (2EHA), 1 part by mass of N, N-diethylacrylamide (DEAA), ethoxydiethylene glycol acrylate ( EDE) 1 part by mass, 4-hydroxybutyl acrylate (HBA) 4 parts by mass, 2,2′-azobisisobutyronitrile 0.2 part by mass as a polymerization initiator, ethyl acetate 150 parts by mass, and gently stirring While introducing nitrogen gas, the temperature of the liquid in the flask was kept at around 60 ° C. to conduct a polymerization reaction for 5 hours to prepare an acrylic polymer solution (40% by mass). The acrylic polymer had a weight average molecular weight of 570,000 and a glass transition temperature (Tg) of −68 ° C.

<Preparation of acrylic adhesive solution>
The acrylic polymer solution (40% by mass) is diluted to 20% by mass with ethyl acetate, and 500 parts by mass (100 parts by mass of the solid content) of this solution is used as 1-butyl-3-methylpyridinium bis ( Trifluoromethanesulfonyl) imide (BMP) 0.2 part by mass (solid content 0.2 part by mass), as a crosslinking agent, isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX: C / HX) 2 parts by mass 2 parts by weight (solid content 2 parts by weight) and 2 parts by weight dibutyltin dilaurate (1% by weight ethyl acetate solution) (solid content 0.02 parts by weight) as a crosslinking catalyst are mixed and stirred to prepare an acrylic adhesive solution. Prepared.

<Preparation of antistatic layer solution>
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 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 solution having an NV of about 0.4% was prepared.

<Preparation of support (base material) with antistatic layer>
As a support, the antistatic layer solution is dried on the corona-treated surface of 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 that has been subjected to corona treatment on one side. It apply | coated so that latter thickness might be set to 30 nm. The coated material was heated to 130 ° C. for 1 minute and dried to prepare a support (base material) with an antistatic layer having an antistatic layer on one side of the PET film.

<Preparation of pressure-sensitive adhesive sheet (surface protective film)>
The acrylic pressure-sensitive adhesive solution was applied to the surface opposite to the antistatic layer of the support (base material) with the antistatic layer, 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 to 7 and Comparative Examples 1 to 3]
Based on the contents of Table 1, a pressure-sensitive adhesive sheet (surface protective film) was produced in the same manner as in Example 1. In addition, the other additive which is not mix | blended in Example 1 was mix | blended at the same timing as an antistatic agent. Moreover, the compounding quantity in Table 1 showed solid content.

  Table 1 shows the results of various measurements and evaluations described above for the pressure-sensitive adhesive sheets according to Examples and Comparative Examples.

Abbreviations in Table 1 will be described below.
2EHA: 2-ethylhexyl acrylate BA: n-butyl acrylate DEAA: N, N-diethylacrylamide DMAA: N, N-dimethylacrylamide ACMO: acryloylmorpholine CHM: N-cyclohexylmaleimide EDE: ethoxydiethylene glycol acrylate PME-400: methoxy Polyethylene glycol monoacrylate (EO addition moles: approx. 9, NOF Corporation)
PME-1000: Methoxypolyethylene glycol monoacrylate (EO addition moles: about 23, manufactured by NOF Corporation)
HBA: 4-hydroxybutyl acrylate AA: acrylic acid KF355A: organopolysiloxane having an oxyalkylene chain (HLB value 12) (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-355A)
KF353: Organopolysiloxane having an oxyalkylene chain (HLB value 10) (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: KF-353)
C / HX: Isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Co., Ltd., trade name: Coronate HX)
BMP: 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide (ionic liquid, liquid at 25 ° C., Wako Pure Chemical Industries, Ltd.)
OMP: 1-octyl-4-methylpyridinium hexafluorophosphate (ionic liquid, melting point: 44 ° C.)
BP: 1-butylpyridinium hexafluorophosphate (ionic liquid, melting point: 75 ° C., Wako Pure Chemical Industries, Ltd.)
LiTFSI: Lithium bis (trifluoromethanesulfonyl) imide (alkali metal salt, Kishida Chemical Co., Ltd.)
25R-1: ADEKA Corporation, trade name “Adekapluronic 25R-1” (number average molecular weight 2800, ethylene oxide group content 10 mass%, active ingredient 100 mass%)

  From Table 1, it was confirmed that in all Examples, the shearing force at the time of low-speed peeling and the peeling antistatic property were excellent. On the other hand, in Comparative Example 1, since the nitrogen-containing monomer was not used, the cohesive force of the pressure-sensitive adhesive was low and the shearing force was inferior. In Comparative Example 2, since the alkylene oxide group-containing monomer was not used, the melting point was Ion conduction caused by an organic salt of 150 ° C. or lower is hindered, and the antistatic property of peeling is inferior. Since it mix | blended and the alkylene oxide group containing monomer was used excessively, it was confirmed that the cohesive force of an adhesive became low and it was inferior to shear force.

  The pressure-sensitive adhesive sheet disclosed herein protects the optical member during production, transportation and the like of an optical member used as a component of a liquid crystal display panel, a plasma display panel (PDP), an organic electroluminescence (EL) display, or the like. Therefore, it is suitable as a surface protective film. In particular, surface protective films (optical surfaces) applied to optical members such as polarizing plates (polarizing films) for liquid crystal display panels, wave plates, phase difference plates, optical compensation films, brightness enhancement films, light diffusion sheets, and reflective sheets It is useful as a protective film.

1: Adhesive sheet 10: Acrylic plate 20: Polarizing plate 30: Sample fixing base 40: Potential measuring device

Claims (5)

As a monomer component, 40% by mass or more of a (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms, 1 to 5% by mass of a nitrogen-containing monomer, and 0.5 to 40% by mass of an alkylene oxide group-containing monomer. % (Meth) acrylic polymer containing no carboxyl group-containing monomer, and
A pressure-sensitive adhesive composition comprising an organic salt having a melting point of 150 ° C. or less and / or an alkali metal salt.   The pressure-sensitive adhesive composition according to claim 1, wherein the organic salt having a melting point of 150 ° C or lower 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. object.   The pressure-sensitive adhesive composition according to claim 1 or 2, further comprising an alkylene oxide group-containing compound not containing an organopolysiloxane having a number average molecular weight of 10,000 or less.   A pressure-sensitive adhesive sheet formed by forming a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition according to claim 1 on one side or both sides of a support. An optical member comprising the pressure-sensitive adhesive sheet according to claim 4 bonded thereto.