JP2006063311A - Pressure-sensitive adhesive composition, pressure-sensitive adhesive sheet and surface-protection film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive composition exhibiting antistatic effect in the case of peeling a non-anti-staticized adherend, giving decreased stain of the adherend and having excellent bonding reliability, an antistatic pressure-sensitive sheet produced by using the composition and a surface-protection film. <P>SOLUTION: The pressure-sensitive adhesive composition contains an ionic liquid and a (meth)acrylic polymer containing 0.1-100 wt.% (meth)acrylic acid alkylene oxide as a monomer unit. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an antistatic pressure-sensitive adhesive composition, and an antistatic pressure-sensitive adhesive sheet and a surface protective film which are formed into a sheet shape or a tape shape using the same. The pressure-sensitive adhesive sheets comprising the antistatic pressure-sensitive adhesive composition of the present invention are suitably used for plastic products and the like that are likely to generate static electricity. Especially, it is useful as an antistatic pressure-sensitive adhesive sheet and a surface protective film used in applications that dislike static electricity such as electronic devices.

  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 an adhesive and the surfactant is transferred from the adhesive to an adherend to prevent electrification (see, for example, Patent Document 1). However, in the present invention, the surfactant is easily bleed on the pressure-sensitive adhesive surface, and when applied to a protective film, there is a concern about contamination of the adherend. Therefore, when a pressure-sensitive adhesive 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, and as a result, when applied to a surface protective film, if the treatment is performed over time or under high temperature, the adherend is contaminated by the bleeding phenomenon. It turns out that it occurs.
JP-A-9-165460 JP-A-6-128539

  In light of such circumstances, the present invention is a pressure-sensitive adhesive composition that is capable of preventing charging of an adherend that is not antistatic when peeled, has reduced contamination on the adherend, and has excellent adhesion reliability. And an antistatic pressure-sensitive adhesive sheet using the same, and a surface protective film.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by the pressure-sensitive adhesive composition shown below, and have completed the present invention.

  That is, the pressure-sensitive adhesive composition of the present invention contains an ionic liquid and a (meth) acrylic polymer having 0.1 to 100% by weight of (meth) acrylic acid alkylene oxide as a monomer unit. Features.

  According to the pressure-sensitive adhesive composition of the present invention, as shown in the results of Examples, a (meth) acrylic polymer having 0.1 to 100% by weight of (meth) acrylic acid alkylene oxide as a monomer unit is used as a base polymer. Further, since the ionic liquid is further contained, the pressure-sensitive adhesive layer obtained by crosslinking the ionic liquid has reduced anti-contamination properties to the protected body and has excellent antistatic properties when peeled off. Although the details of the reason why the crosslinked product of the base polymer using the (meth) acrylic acid alkylene oxide as a monomer component exhibits such characteristics are not clear, an ionic liquid is arranged on the ether group in the acrylic acid alkylene oxide. It is presumed that the ionic liquid is less likely to bleed by positioning, and excellent antistatic properties and low contamination are realized in parallel.

  The ionic liquid in the present invention refers to a molten salt (ionic compound) that is liquid at room temperature (25 ° C.).

  The pressure-sensitive adhesive composition of the present invention uses the above ionic liquid as an antistatic agent, and suppresses bleeding of the antistatic agent, and has excellent adhesion reliability to an adherend even over time or at high temperatures. It becomes. Although the reason why bleeding is suppressed by using an ionic liquid is not clear, it is presumed that the compatibility with the base polymer is higher than that of a surfactant or the like. In addition, since the ionic liquid exhibits excellent electrical conductivity by itself, sufficient antistatic ability can be obtained even if the contamination on the surface of the adherend is very small.

  Further, since the above ionic liquid is preferably in a liquid state at room temperature, it can be easily added and dispersed or dissolved in the pressure-sensitive adhesive as compared with a solid salt. Furthermore, since the ionic liquid has no vapor pressure (non-volatile), it does not disappear over time, and the antistatic property can be continuously obtained.

  In the pressure-sensitive adhesive composition of the present invention, a (meth) acrylic polymer having 0.1 to 100% by weight of (meth) acrylic acid alkylene oxide as a monomer unit is used as a base polymer. In addition, the (meth) acrylic polymer in the present invention refers to an acrylic polymer and / or a methacrylic polymer. In addition, alkyl (meth) acrylate refers to alkyl acrylate and / or alkyl methacrylate, and (meth) acrylate refers to acrylate and / or methacrylate.

  In the above, it is preferable that the ionic liquid is at least one of a nitrogen-containing onium salt, a sulfur-containing onium salt, and a phosphorus-containing onium salt. In particular, the ionic liquid preferably contains one or more cations represented by the following general formulas (A) to (D). An ionic liquid having these cations provides a further excellent antistatic ability.

［式（Ａ）中のＲ_ａは、炭素数４から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ_ｂ及びＲ_ｃは、同一又は異なって、水素又は炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。但し、窒素原子が２重結合を含む場合、Ｒ_ｃはない。］
［式（Ｂ）中のＲ_ｄは、炭素数２から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ_ｅ、Ｒ_ｆ、及びＲ_ｇは、同一又は異なって、水素又は炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。］
［式（Ｃ）中のＲ_ｈは、炭素数２から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ_ｉ、Ｒ_ｊ、及びＲ_ｋは、同一又は異なって、水素又は炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。］
［式（Ｄ）中のＺは、窒素、硫黄、又はリン原子を表し、Ｒ_ｌ、Ｒ_ｍ、Ｒ_ｎ、及びＲ_ｏは、同一又は異なって、炭素数１から２０の炭化水素基を表し、ヘテロ原子を含んでも良い。但しＺが硫黄原子の場合、Ｒ_ｏはない。］

[R _a in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms and may include a hetero atom, and R _b and R _c may be the same or different, and may be hydrogen or _C 1 to 16 carbon atoms. It represents a hydrocarbon group and may contain 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 contain a hetero atom, and R _e , R _f , and R _g are the same or different and represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[R _h in the formula (C) represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a hetero atom, and R _i , R _j , and R _k may be the same or different and each may represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[Z in Formula (D) represents a nitrogen, sulfur, or phosphorus atom, and R ₁ , R _m , R _n , and _Ro represent the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms. , And may contain a heteroatom. However, when Z is a sulfur atom, there is no _Ro . ]

  Furthermore, in this invention, it becomes an adhesive composition which was further excellent in antistatic property by using together an ethylene oxide group containing compound.

  The ethylene oxide compound used in the present invention is preferably a surfactant having an ethylene oxide group. By using these surfactants having an ethylene oxide group, the compatibility with the ionic liquid and the base polymer is improved, bleeding to the adherend is suppressed, and a low-contamination pressure-sensitive adhesive composition is obtained.

  On the other hand, the pressure-sensitive adhesive layer of the present invention is formed by crosslinking the pressure-sensitive adhesive composition described above. By appropriately adjusting the structural unit, the structural ratio, the selection of the crosslinking agent, the addition ratio, and the like of the (meth) acrylic polymer to perform crosslinking, pressure-sensitive adhesive sheets having more excellent heat resistance and the like can be obtained.

  The pressure-sensitive adhesive sheet of the present invention is characterized in that a pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition described above is formed on a support. According to the pressure-sensitive adhesive sheets of the present invention, since the pressure-sensitive adhesive composition is provided with a pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition having the above-described effects, it is possible to prevent charging to an adherend that is not antistatic when peeled. Thus, pressure-sensitive adhesive sheets having excellent adhesion reliability with reduced contamination to the adherend are obtained.

  Furthermore, when the pressure-sensitive adhesive composition of the present invention is applied to a surface protective film, the plastic substrate used for the protective film is more preferably subjected to antistatic treatment. By subjecting the plastic substrate to an antistatic treatment, it is possible to more effectively reduce the stripping voltage on the adherend, and further to obtain an excellent antistatic ability.

  The pressure-sensitive adhesive composition of the present invention comprises an ionic liquid and a (meth) acrylic polymer having 0.1 to 100% by weight of (meth) acrylic acid alkylene oxide as a monomer unit. To do.

  As the ionic liquid, a nitrogen-containing onium salt, a sulfur-containing onium salt, or a phosphorus-containing onium salt is preferably used, and is represented by the following general formulas (A) to (D) for the reason that particularly excellent antistatic ability is obtained. What consists of an organic cation component and an anion component is used preferably.

［式（Ａ）中のＲ_ａは、炭素数４から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ_ｂ及びＲ_ｃは、同一又は異なって、水素又は炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。但し、窒素原子が２重結合を含む場合、Ｒ_ｃはない。］
［式（Ｂ）中のＲ_ｄは、炭素数２から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ_ｅ、Ｒ_ｆ、及びＲ_ｇは、同一又は異なって、水素又は炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。］
［式（Ｃ）中のＲ_ｈは、炭素数２から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ_ｉ、Ｒ_ｊ、及びＲ_ｋは、同一又は異なって、水素又は炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。］
［式（Ｄ）中のＺは、窒素、硫黄、又はリン原子を表し、Ｒ_ｌ、Ｒ_ｍ、Ｒ_ｎ、及びＲ_ｏは、同一又は異なって、炭素数１から２０の炭化水素基を表し、ヘテロ原子を含んでも良い。但しＺが硫黄原子の場合、Ｒ_ｏはない。］

[R _a in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms, and may include a hetero atom, and R _b and R _c may be the same or different, and may be hydrogen or _{C 1-16} It represents a hydrocarbon group and may contain 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 contain a hetero atom, and R _e , R _f , and R _g are the same or different and represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[R _h in the formula (C) represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a hetero atom, and R _i , R _j , and R _k may be the same or different and each may represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[Z in 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. , And may contain a heteroatom. However, when Z is a sulfur atom, there is no _Ro . ]

  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, and a cation having a pyrrole skeleton.

  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 Examples thereof include a nium cation, a 2-methyl-1-pyrroline cation, a 1-ethyl-2-phenylindole cation, a 1,2-dimethylindole cation, and a 1-ethylcarbazole cation.

  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, 1,3-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-dihydropyrimidi Cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydro Pyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,6-dihydropyrimidini Such as Mukachion, and the like.

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

  Specific examples include 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2-methylpyrazolinium cation and the like.

  As the cation represented by the formula (D), for example, a tetraalkylammonium cation, a trialkylsulfonium cation, a tetraalkylphosphonium cation, or 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 tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrahexylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, N, N-diethyl-N-methyl-N -(2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, N, N-dimethyl-N, N-dipropylammonium cation, N, N-dimethyl-N, N-dihexylammonium cation, N, N-dipropyl- N, N-dihexylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, Silsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecyl Examples include phosphonium cations and diallyldimethylammonium cations.

  Among them, triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, N, N-dimethyl-N- Ethyl-N-propylammonium 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-propyl-N- Butylan Nium 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-dimethyl-N-butyl-N-hexylammonium cation, N, N-dimethyl-N-butyl-N-heptylammonium cation, N, N-dimethyl-N-pentyl-N-hexylammonium cation, trimethyl Heptylammonium 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 Pyr-N-pentylammonium cation, triethylmethylammonium 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-dibutyl-N-methyl-N-pentylammonium cation, N, N-dibutyl-N- Asymmetric tetraalkylammonium such as methyl-N-hexylammonium cation, trioctylmethylammonium cation, N-methyl-N-ethyl-N-propyl-N-pentylammonium cation Asymmetric tetraalkylphosphonium cations such as trialkylsulfonium cations such as nium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation and dimethyldecylsulfonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation and trimethyldecylphosphonium cation are preferably used. .

On the other hand, the anion component is not particularly limited as long as it satisfies that it becomes an ionic liquid. For example, Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , F (HF) _n ⁻ , (CN) ₂ N ⁻ , C ₄ F ₉ SO ₃ ⁻ , (C ₂ F ₅ SO ₂ ) ₂ N ⁻ , C ₃ F ₇ COO ⁻ , (CF ₃ SO ₂ ) (CF ₃ CO) N ⁻ or the like is used. Among these, an anion component containing a fluorine atom is particularly preferably used since an ionic compound having a low melting point can be obtained.

  Specific examples of the ionic liquid used in the present invention are appropriately selected from the combination of the cation component and the anion component, and include 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) ) Imido, 1-hexylpyridinium tetrafluoroborate, 2-methyl-1-pyrroline tetrafluoroborate, 1-ethyl-2-phenylindole tetrafluoroborate, 1,2-dimethyli Dole tetrafluoroborate, 1-ethylcarbazole tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium heptafluorobutyrate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium perfluorobutanesulfonate, 1-ethyl-3-methylimidazolium di Cyanamide, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium bis (pentafluoroethanesulfonyl) imide, 1-ethyl 3-methylimidazolium tris (trifluoromethanesulfonyl) imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium trifluoro Acetate, 1-butyl-3-methylimidazolium heptafluorobutyrate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium perfluorobutanesulfonate, 1-butyl-3-methylimidazole Bis (trifluoromethanesulfonyl) imide, 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, 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, 3-methylpyrazolium tetrafluoroborate, tetrahexylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium tetrafluoroborate, diary Dimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium bis (pentafluoroethanesulfonyl) imide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium tetrafluoro Borate, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium trifluoromethanesulfonate, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) Imido, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium trifluorometa Sulfonate, glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, glycidyltrimethylammonium bis (pentafluoroethanesulfonyl) imide, 1-butylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl) ) Trifluoroacetamide, 1-ethyl-3-methylimidazolium (trifluoromethanesulfonyl) trifluoroacetamide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium (trifluoromethanesulfonyl) trifluoroacetamide , Diallyldimethylammonium (trifluoromethanesulfonyl) trifluoroacetamide, glycidyltrimethyl Ammonium (trifluoromethanesulfonyl) trifluoroacetamide, N, N-dimethyl-N-ethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-butylammonium bis (trifluoromethane Sulfonyl) 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 (trifluoromethane Sulfonyl) imide, N, N-dimethyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-heptylammonium bis (trifluoromethanesulfonyl) imi N, N-dimethyl-N-pentyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N, N-dihexylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoro) (Romethanesulfonyl) 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, Ethylpropylammonium bis (trifluoromethanesulfonyl) imide, triethylpentylammonium bis (trifluoromethanesulfonyl) imide, triethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-methyl-N-ethylammonium bis (trifluoro) Romethanesulfonyl) 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-dihexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-pentylammonium (Trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) imide, N-methyl-N-ethyl- N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide and the like can be mentioned.

  A commercially available ionic liquid as described above may be used, but it can also be synthesized as follows. The method for synthesizing the ionic liquid is not particularly limited as long as the target ionic liquid is obtained. In general, the document “ionic liquids—the forefront and future of development” [CMC Publishing Co., Ltd.] The halide method, the hydroxide method, the acid ester method, the complex formation method, the neutralization method and the like as described in “Issuance” are used.

  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, but other sulfur-containing onium salts, phosphorus-containing onium salts, etc. This ionic liquid can also 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), and chlorine, bromine, and iodine are used as the halogen).

Acid (HA) or salt having the anionic structure (A ⁻ ) of the ionic liquid intended for the obtained halide (MA and M are cations that form a salt with the intended anion such as ammonium, lithium, sodium, potassium, etc.) ) To obtain the desired ionic liquid (R ₄ NA).

水酸化物法は、（４）〜（８）に示すような反応によって行われる方法である。まずハロゲン化物（Ｒ_４ＮＸ）をイオン交換膜法電解（反応式（４））、ＯＨ型イオン交換樹脂法（反応式（５））又は酸化銀（Ａｇ_２Ｏ）との反応（反応式（６））で水酸化物（Ｒ_４ＮＯＨ）を得る（ハロゲンとしては塩素、臭素、ヨウ素が用いられる）。

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 a hydroxide (R ₄ NOH) (chlorine, bromine and iodine are used as the halogen).

The target ionic liquid (R ₄ NA) can be obtained from the obtained hydroxide using the reactions of the reaction formulas (7) to (8) in the same manner as the halogenation method.

酸エステル法は、（９）〜（１１）に示すような反応によって行われる方法である。まず３級アミン（Ｒ_３Ｎ）を酸エステルと反応させて酸エステル物を得る（反応式（９）、酸エステルとしては、硫酸、亜硫酸、りん酸、亜りん酸、炭酸などの無機酸のエステルやメタンスルホン酸、メチルホスホン酸、蟻酸などの有機酸のエステルなどが用いられる）。

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)). The acid ester includes inorganic acids such as sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid, and carbonic acid. Esters and esters of organic acids such as methanesulfonic acid, methylphosphonic acid and formic acid are used).

The target ionic liquid (R ₄ NA) is obtained from the obtained acid ester using the reactions of the reaction formulas (10) to (11) in the same manner as the halogenation method. Further, by using methyl trifluoromethanesulfonate, methyl trifluoroacetate or the like as the acid ester, an ionic liquid can be directly obtained.

錯形成法は、（１２）〜（１５）に示すような反応によって行われる方法である。まず４級アンモニウムのハロゲン化物（Ｒ_４ＮＸ）、４級アンモニウムの水酸化物（Ｒ_４ＮＯＨ）、４級アンモニウムの炭酸エステル化物（Ｒ_４ＮＯＣＯ_２ＣＨ_３）などをフッ化水素（ＨＦ）やフッ化アンモニウム（ＮＨ_４Ｆ）と反応させてフッ化４級アンモニウム塩を得る（反応式（１２）〜（１４））。

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)).

An ionic liquid can be obtained by complexing the obtained quaternary ammonium fluoride with a fluoride such as BF ₃ , AlF ₃ , PF ₅ , ASF ₅ , SbF ₅ , NbF ₅ , TaF ₅ (reaction) Formula (15)).

中和法は、（１６）に示すような反応によって行われる方法である。３級アミンとＨＢＦ_４，ＨＰＦ_６，ＣＨ_３ＣＯＯＨ，ＣＦ_３ＣＯＯＨ，ＣＦ_３ＳＯ_３Ｈ，（ＣＦ_３ＳＯ_２）_２ＮＨ，（ＣＦ_３ＳＯ_２）_３ＣＨ，（Ｃ_２Ｆ_５ＳＯ_２）_２ＮＨなどの有機酸とを反応させることにより得ることができる。

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.

上記の式（１）〜（１６）記載のＲは、水素又は炭素数１から２０の炭化水素基を表し、ヘテロ原子を含んでも良い。

R in the above formulas (1) to (16) represents hydrogen or a hydrocarbon group having 1 to 20 carbon atoms, and may contain a hetero atom.

  The blending amount of the ionic liquid cannot be defined unconditionally because it varies depending on the compatibility of the acrylic polymer to be used and the ionic liquid, but is generally 0.01 to 100 parts by weight of the base polymer. 40 parts by weight is preferable, 0.03 to 20 parts by weight is more preferable, and 0.05 to 10 parts by weight is most preferable. If it is less than 0.01 part by weight, sufficient antistatic properties cannot be obtained, and if it exceeds 40 parts by weight, the contamination of the adherend tends to increase.

  The (meth) acrylic polymer in the present invention is a (meth) acrylic polymer having 0.1 to 100% by weight of (meth) acrylic acid alkylene oxide as a monomer unit.

  The (meth) acrylic polymer used in the present invention is not particularly limited as long as it is a (meth) acrylic polymer having adhesive properties corresponding to those described above.

  Examples of the oxyalkylene unit of the alkylene oxide (meth) acrylate in the present invention 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. Can be given.

  Moreover, it is preferable that it is 1-30 from a compatible viewpoint with an ionic liquid, and, as for the addition mole number of the oxyalkylene unit with respect to the oxyalkylene unit of (meth) acrylic acid, it is more preferable that it is 1-20. The terminal of the oxyalkylene chain may be a hydroxyl group or may be substituted with another functional group or the like. However, in order to appropriately control the crosslinking density, for example, an alkyl group or a phenyl group is substituted. Is preferred.

  Specific examples of the (meth) acrylic acid alkylene oxide in the present invention include, for example, methoxy-polyethylene glycol (meth) acrylate types such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) acrylate, and ethoxy-diethylene glycol. (Meth) acrylate, ethoxy-polyethylene glycol (meth) acrylate type such as ethoxy-triethylene glycol (meth) acrylate, butoxy-polyethylene glycol such as butoxy-diethylene glycol (meth) acrylate, butoxy-triethylene glycol (meth) acrylate ( (Meth) acrylate type, phenoxy-diethylene glycol (meth) acrylate, phenoxy-triethylene glycol Phenoxy such meth) acrylate - polyethylene glycol (meth) acrylate type, methoxy - methoxy dipropylene glycol (meth) acrylate - polypropylene glycol (meth) acrylate type and the like. Of these, ethoxy-diethylene glycol acrylate and the like are preferably used.

  (Meth) acrylic acid alkylene oxide may be used alone or in combination of two or more, but it is 0.1 to 100% by weight in the monomer component of (meth) acrylic polymer. Is preferable, 0.3 to 90% by weight is more preferable, and 0.5 to 80% by weight is particularly preferable. When the content of the (meth) acrylic acid alkylene oxide is less than 0.1% by weight, the effect of suppressing bleeding of the ionic liquid and the effect of reducing the contamination of the protected body are not obtained, which is not preferable.

  In the present invention, in addition to the above (meth) acrylic acid alkylene oxide monomer component, a (meth) acrylic monomer component or (meth) acrylic polymer having an alkyl group having 1 to 14 carbon atoms. Other polymerizable monomer components for adjusting the glass transition point and releasability can be used.

  As the (meth) acrylic monomer component having an alkyl group having 1 to 14 carbon atoms, it is preferable to use a (meth) acrylic monomer having an alkyl group having 2 to 13 carbon atoms. Specific examples 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 ( And (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, and the like.

  Among them, 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 and the like are preferably used.

  The (meth) acrylic monomer component having an alkyl group having 1 to 14 carbon atoms may be used alone or as a mixture of two or more, but the total content Is preferably 0 to 99.9% by weight, more preferably 10 to 99.7% by weight, and particularly preferably 20 to 99.5% by weight in the monomer component of the (meth) acrylic polymer. By using the (meth) acrylic monomer component having an alkyl group having 1 to 14 carbon atoms, good interaction with the ionic liquid and good adhesiveness can be appropriately adjusted.

  In addition, as other polymerizable monomer components, a polymerizable monomer for adjusting the glass transition point and peelability of the (meth) acrylic polymer can be used as long as the effects of the present invention are not impaired. .

  Other polymerizable monomer components include, for example, components for improving cohesion and heat resistance such as sulfonic acid group-containing monomers, phosphate group-containing monomers, cyano group-containing monomers, vinyl esters, aromatic vinyl compounds, and carboxyl Adhesion improvement and crosslinking of group-containing monomer, acid anhydride group-containing monomer, hydroxyl group-containing monomer, amide group-containing monomer, amino group-containing monomer, imide group-containing monomer, epoxy group-containing monomer, N-acryloylmorpholine, vinyl ethers, etc. A component having a functional group serving as a linking base point can be used as appropriate. Other components can be used alone or in combination of two or more.

  However, when using an acrylate and / or methacrylate having an acid functional group such as a carboxyl group, a sulfonic acid group, or a phosphoric acid group, it is preferable to adjust the acrylic polymer so that the acid value is 29 or less. When the acid value of the acrylic polymer exceeds 29, the antistatic property tends to deteriorate.

  The acid value can be adjusted by adjusting the amount of acrylate and / or methacrylate having an acid functional group. For example, an acrylic polymer obtained by copolymerizing 2-ethylhexyl acrylate and acrylic acid as an acrylic polymer having a carboxyl group. In this case, the acid value can be satisfied by adjusting the acrylic acid to 3.7 parts by weight or less with respect to 100 parts by weight of the total amount of 2-ethylhexyl acrylate and acrylic acid.

  Examples of the sulfonic acid group-containing monomer include styrene sulfonic acid, allyl sulfonic acid, 2- (meth) acrylamide-2-methylpropane sulfonic acid, (meth) acrylamide propane sulfonic acid, sulfopropyl (meth) acrylate, and (meth). Examples include acryloyloxynaphthalene sulfonic acid and sodium vinyl sulfonate.

  Examples of the phosphate group-containing monomer include 2-hydroxyethyl acryloyl phosphate.

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

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

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

  Examples of the carboxyl group-containing monomer include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

  Examples of the acid anhydride group-containing monomer include maleic anhydride, itaconic anhydride, and acid anhydride bodies of the above carboxyl group-containing monomers.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 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-hydroxyethyl Examples thereof include vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and the like.

  Examples of amide group-containing monomers include acrylamide, methacrylamide, diethyl acrylamide, N-vinyl pyrrolidone, N, N-dimethyl acrylamide, N, N-dimethyl methacrylamide, N, N-diethyl acrylamide, N, N-diethyl methacryl. Examples thereof include amide, N, N′-methylenebisacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminopropylmethacrylamide and the like.

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

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

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

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

  The other polymerizable monomer components described above may be used alone or in admixture of two or more, but the total content is all structural units of the (meth) acrylic polymer The polymerizable monomer component is preferably 0 to 85 parts by weight, more preferably 1 to 80 parts by weight, and particularly preferably 2 to 75 parts by weight with respect to 100 parts by weight. By using the other polymerizable monomer components described above, good interaction with the ionic liquid and good adhesiveness can be appropriately adjusted.

  The (meth) acrylic polymer used in the present invention has a weight average molecular weight of 100,000 to 5,000,000, preferably 200,000 to 4,000,000, more preferably 300,000 to 3,000,000. When the weight average molecular weight is smaller than 100,000, the adhesive force tends to be generated due to a decrease in the cohesive force of the pressure-sensitive adhesive composition. On the other hand, when the weight average molecular weight exceeds 5,000,000, the fluidity of the polymer decreases and the wettability to the polarizing plate becomes insufficient, and the swelling generated between the polarizing plate and the pressure-sensitive adhesive composition layer of the surface protective film is reduced. There is a tendency to cause. A weight average molecular weight means what was obtained by measuring by GPC (gel permeation chromatography).

  Moreover, although the glass transition temperature (Tg) of the said (meth) acrylic-type polymer is normally -100 degreeC or more, it is preferable that it is -90 degreeC-0 degreeC, and it is -80 degreeC--10 degreeC. More preferably. When the glass transition temperature is higher than 0 ° C., the polymer is difficult to flow and the wetting to the polarizing plate is insufficient, and there is a tendency to cause blisters generated between the polarizing plate and the pressure-sensitive adhesive composition layer of the surface protective film. is there. In addition, the glass transition temperature (Tg) 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.

  The (meth) acrylic polymer of the present invention can be obtained by a polymerization method generally used as a synthesis method of an acrylic polymer such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization. Further, the polymer obtained may be any of random copolymer, block copolymer and the like.

  The pressure-sensitive adhesive composition of the present invention can appropriately contain an ethylene oxide group-containing compound.

  The ethylene oxide group-containing compound in the present invention is not particularly limited as long as it is a compound having an ethylene oxide group. For example, a surfactant having an ethylene oxide group, an ethylene oxide group-containing polyether polymer or an ethylene glycol group-containing (meth) acrylic compound. Examples include polymers. Among these, a surfactant having an ethylene oxide group is preferably used because it is easy to balance the compatibility with the base polymer and the ionic liquid.

  Examples of the surfactant having an ethylene oxide group include polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, Nonionic surfactants such as polyoxyethylene alkylphenyl ethers, polyoxyethylene derivatives, polyoxyethylene alkylamines, polyoxyethylene alkylamine fatty acid esters, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl Anionic surfactants such as ether phosphates, polyoxyethylene alkylphenyl ether phosphates, and cationic interfaces having ethylene oxide groups Sex agents and zwitterionic surfactants. Moreover, you may have reactive substituents, such as a (meth) acryloyl group and an allyl group, in a molecule | numerator.

  The added mole number of the oxyethylene unit of the surfactant having an ethylene oxide group is preferably 1 to 50, more preferably 2 to 40, from the viewpoint of interaction with the ionic liquid. The absence of an ethylene oxide group is not preferable because it is difficult to balance the compatibility with the ionic liquid and the base polymer, and the bleed to the adherend tends to increase. On the other hand, when a surfactant having an added mole number of oxyethylene units exceeding 50 is used, it is not preferable because the ionic liquid is bound by the ethylene oxide group and the antistatic property tends to be lowered.

  Polyethylene polymers containing ethylene oxide groups include polypropylene glycol-polyethylene glycol-polypropylene glycol block copolymers, polypropylene glycol-polyethylene glycol block copolymers, polyethylene glycol-polypropylene glycol-polyethylene glycol block copolymers, polypropylene Examples thereof include random copolymers and block copolymers of polyethylene glycol and polypropylene glycol, such as a random copolymer of glycol-polyethylene glycol.

  The polyethylene glycol ratio of the random copolymer or block copolymer of polyethylene glycol and polypropylene glycol is preferably 5 to 74% by weight, more preferably 10 to 70% by weight. If the polyethylene glycol ratio is less than 5% by weight, the compatibility with the ionic liquid tends to be poor, and sufficient antistatic properties tend to be difficult to obtain. On the other hand, if it exceeds 74% by weight, the crystallinity is high. Therefore, the compatibility with the acrylic polymer tends to be poor, and sufficient antistatic properties tend to be difficult to obtain.

  As the ethylene glycol group-containing (meth) acrylic polymer, an acrylic polymer containing ethylene glycol group-containing (meth) acrylate as an essential component is used.

  The number of moles of oxyethylene units added to the (meth) acrylate is preferably from 1 to 30, and more preferably from 2 to 20, from the viewpoint of coordination of the ionic liquid. 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.

  Specific examples of the ethylene glycol group-containing (meth) acrylate include, for example, methoxy-polyethylene glycol (meth) acrylate types such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) acrylate, ethoxy-diethylene glycol (meta ) Acrylate, ethoxy-polyethylene glycol (meth) acrylate type such as ethoxy-triethylene glycol (meth) acrylate, butoxy-polyethylene glycol (meth) such as butoxy-diethylene glycol (meth) acrylate, butoxy-triethylene glycol (meth) acrylate Acrylate type, phenoxy-diethylene glycol (meth) acrylate, phenoxy-triethylene glycol (meth) Phenoxy, such as acrylate - polyethylene glycol (meth) acrylate type, 2-ethylhexyl - polyethylene glycol (meth) acrylate, nonylphenol - polyethylene glycol (meth) acrylate type and the like.

  In addition to the above components, 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 Use of acrylates and / or methacrylates having an alkyl group of 1 to 14 carbon atoms such as (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, etc. It is also possible.

  Furthermore, carboxyl group-containing (meth) acrylate, phosphate 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 and the like can also be used as appropriate.

  The proportion of the ethylene glycol group-containing (meth) acrylate contained in the ethylene glycol group-containing (meth) acrylate polymer is preferably 10 to 70% by weight. When the proportion of the ethylene glycol group-containing (meth) acrylate is less than 10% by weight, the compatibility with the ionic liquid is deteriorated and sufficient charging characteristics cannot be obtained. Compatibility with a certain acrylic polymer is deteriorated and sufficient charging characteristics cannot be obtained.

  Moreover, said (meth) acrylate may be used independently and may be used in combination.

  As the molecular weight of the ethylene oxide group-containing polyether polymer or ethylene glycol group-containing (meth) acrylic polymer, those having a number average molecular weight of 10,000 or less are preferably used, and those having a molecular weight of 200 to 5000 are more preferably used. When the number average molecular weight exceeds 10,000, the contamination of the adherend tends to deteriorate. The number average molecular weight is obtained by measuring by GPC (gel permeation chromatography).

  The ethylene oxide group-containing compound may be used alone or in combination, but the blending amount is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the base polymer. More preferably, the amount is 0.05 parts by weight to 5 parts by weight. If the amount is less than 0.01 part by weight, sufficient charging characteristics cannot be obtained, and if it exceeds 10 parts by weight, bleeding to the adherend tends to increase and the adhesive strength tends to decrease, such being undesirable.

  The pressure-sensitive adhesive of the present invention can provide pressure-sensitive adhesive sheets having further excellent heat resistance by appropriately crosslinking a base polymer, particularly an acrylic polymer. As specific means of the crosslinking method, it can react with a carboxyl group, a hydroxyl group, an amino group, an amide group, or the like appropriately included as a crosslinking base in an acrylic polymer such as an isocyanate compound, an epoxy compound, a melamine resin, or an aziridine compound. There is a method using a so-called crosslinking agent in which a compound having a group is added and reacted. Among these, an isocyanate compound and an epoxy compound are particularly preferably used mainly from the viewpoint of obtaining an appropriate cohesive force. These compounds may be used alone or in combination of two or more.

  Among these, examples of the isocyanate compound include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

  More specifically, as the isocyanate compound, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, 2, 4 -Aromatic diisocyanates such as tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylol Propane / hexamethylene diisocyanate trimer adduct (trade name Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.), hexamethylene diisocyanate Isocyanurate of (Nippon Polyurethane Industry Co., Ltd., trade name: Coronate HX), and the like, such as isocyanate adducts such as. 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 (manufactured by Mitsubishi Gas Chemical Company, trade name: TETRAD-X) and 1,3-bis (N, N-diglycidyl). Aminomethyl) cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Company, Inc.). These compounds may be used alone or in combination of two or more.

  Examples of the melamine resin include hexamethylol melamine.

  Examples of the aziridine derivative include a commercially available product name HDU (manufactured by Mutual Pharmaceutical Company), a product name TAZM (manufactured by Mutual Pharmaceutical Company), and a product name TAZO (manufactured by Mutual Pharmaceutical Company). These compounds may be used alone or in combination of two or more.

  The amount of these crosslinking agents to be used is appropriately selected depending on the balance with the acrylic polymer to be crosslinked, and further depending on the intended use as an adhesive sheet. In general, in order to obtain sufficient heat resistance due to the cohesive strength of the acrylic pressure-sensitive adhesive, it is preferably contained in an amount of 0.01 to 15 parts by weight with respect to 100 parts by weight of the acrylic polymer. More preferably, 10 parts by weight is contained. When the content is less than 0.01 parts by weight, the crosslinking formation by the crosslinking agent becomes insufficient, the cohesive strength of the pressure-sensitive adhesive composition becomes small, and sufficient heat resistance may not be obtained. There is a tendency to cause the rest. On the other hand, when the content exceeds 15 parts by weight, the cohesive force of the polymer is large, the fluidity is lowered, the wettability to the adherend is insufficient, and it tends to cause peeling.

  Further, it can be added as a polyfunctional monomer having two or more radiation-reactive unsaturated bonds as a substantial cross-linking agent, and cross-linked by radiation or the like. Polyfunctional monomers having two or more radiation-reactive unsaturated bonds include one or more types of radiation that can be crosslinked (cured) by irradiation with radiation such as vinyl, acryloyl, methacryloyl, and vinylbenzyl groups. A polyfunctional monomer component having two or more reactivity is used. In general, those having 10 or less radiation-reactive unsaturated bonds are preferably used. Two or more polyfunctional monomers can be used in combination.

  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 hexanediol. Examples include di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, divinylbenzene, and N, N′-methylenebisacrylamide.

  The amount of the polyfunctional monomer used is appropriately selected depending on the balance with the acrylic polymer to be crosslinked and further depending on the intended use as an adhesive sheet. In general, in order to obtain sufficient heat resistance by the cohesive force of the acrylic pressure-sensitive adhesive, it is preferably blended at 0.1 to 30 parts by weight with respect to 100 parts by weight of the acrylic polymer. Moreover, it is more preferable to mix | blend at 10 weight part or less with respect to 100 weight part of acrylic 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, and the like, and ultraviolet rays are preferably used from the viewpoints of controllability, good handleability, and cost. More preferably, ultraviolet rays having a wavelength of 200 to 400 nm are used. Ultraviolet rays can be irradiated using an appropriate light source such as a high-pressure mercury lamp, a microwave excitation lamp, or a chemical lamp. In addition, when using an ultraviolet-ray as a radiation, a photoinitiator is added to an acrylic adhesive.

  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-benzoyl benzoic acid methyl-p-benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, Acetophenones such as acetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, pros such as 2-hydroxy-2-methylpropiophenone, 2-hydroxy-4′-isopropyl-2-methylpropiophenone Benzophenones such as piophenones, benzophenone, methylbenzophenone, p-chlorobenzophenone, p-dimethylaminobenzofuninone, 2-chlorothioxanthone, 2-ethylthio Thioxanthones such as xanthone 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. About the said photoinitiator, it is also possible to use 2 or more types together.

  The photopolymerization initiator is preferably blended in an amount of usually 0.1 to 10 parts by weight, preferably 0.2 to 7 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer.

  It is also possible to use a photoinitiated polymerization aid such as amines in combination. Examples of the photoinitiator include 2-dimethylaminoethyl benzoate, dimethylaminoacetophenone, p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ester, and the like. Two or more photopolymerization initiation assistants can be used in combination. The polymerization initiation assistant is preferably blended in an amount of 0.05 to 10 parts by weight, more preferably 0.1 to 7 parts by weight, with respect to 100 parts by weight of the acrylic polymer.

  Furthermore, the pressure-sensitive adhesive used in the pressure-sensitive adhesive sheet of the present invention includes various conventionally known tackifiers and surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, polymerization inhibitors, A silane coupling agent, inorganic or organic fillers, powders such as metal powders and pigments, particles, foils, and other conventionally known additives may be added as appropriate depending on the use. it can.

On the other hand, the pressure-sensitive adhesive layer of the present invention is obtained by crosslinking the pressure-sensitive adhesive composition as described above. The pressure-sensitive adhesive sheets of the present invention are formed by forming such a pressure-sensitive adhesive layer on a support film. At that time, the pressure-sensitive adhesive composition is generally crosslinked after application of the pressure-sensitive adhesive composition, but the pressure-sensitive adhesive layer comprising the crosslinked pressure-sensitive adhesive composition can be transferred to a support film or the like. In the case where a photopolymerization initiator as an optional component is added as described above, the pressure-sensitive adhesive composition is applied directly on the object to be protected, or after being applied to one or both sides of the supporting substrate. The pressure-sensitive adhesive layer can be obtained by light irradiation. 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 400 to 4000 mJ / cm ² .

  The method for forming the pressure-sensitive adhesive layer on the film is not particularly limited. For example, the pressure-sensitive adhesive composition is applied to a support film, and the polymerization solvent is dried and formed to form the pressure-sensitive adhesive layer on the support film. Produced. Thereafter, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction. In addition, when the pressure-sensitive adhesive composition is coated on a support film to produce pressure-sensitive adhesive sheets, one or more solvents other than the polymerization solvent are newly added to the composition so that the pressure-sensitive adhesive composition can be uniformly coated on the support film. You may add to.

  Moreover, as a formation method of the adhesive layer of this invention, the well-known method used for manufacture of adhesive sheets is used. Specific examples include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and the like.

  The pressure-sensitive adhesive sheets of the present invention are various supports comprising a plastic film such as a polyester film and a porous material such as paper and nonwoven fabric so that the pressure-sensitive adhesive has a thickness of usually 3 to 100 μm, preferably about 5 to 50 μm. It is applied and formed on one or both sides of the body to form a sheet or tape. Particularly in the case of a surface protective film, it is preferable to use a plastic substrate as a support.

  The plastic substrate is not particularly limited as long as it can be formed into a sheet shape or a film shape. For example, polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene Polyolefin films such as propylene copolymer, ethylene / 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl alcohol copolymer, polyethylene terephthalate, polyethylene naphthalate, poly Polyester film such as butylene terephthalate, polyacrylate film, polystyrene film, nylon 6, nylon 6,6, polyamide film such as partially aromatic polyamide, polyvinyl chloride film, polyvinylidene chloride film, polycarbonate Such as ball titanate film, and the like.

  The thickness of the film is usually about 5 to 200 μm, preferably about 10 to 100 μm.

  For plastic substrates, if necessary, silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agents, mold release with silica powder, etc., acid treatment, acid treatment, alkali treatment, primer treatment, Anti-adhesive treatment such as corona treatment, plasma treatment and ultraviolet treatment, coating type, kneading type, vapor deposition type and the like can also be carried out.

  The plastic substrate used for the surface protective film of the present invention is more preferably subjected to antistatic treatment.

  The antistatic treatment applied to the plastic substrate is not particularly limited. For example, a method of providing an antistatic layer on at least one surface of a generally used film or a method of kneading a kneading type antistatic agent into a plastic film. Used.

  Examples of a method of providing an antistatic layer on at least one surface of the film include, for example, a method of applying an antistatic resin composed of an antistatic agent and a resin component, a conductive polymer, or a conductive resin containing a conductive substance, or a conductive substance. The method of vapor-depositing or plating is mentioned.

  Examples of the antistatic agent contained in the antistatic resin include cationic antistatic agents having cationic functional groups such as quaternary ammonium salts, pyridinium salts, primary, secondary and tertiary amino groups, and sulfones. Anionic antistatic agents having an anionic functional group such as acid salt, sulfate ester salt, phosphonate salt and phosphate ester salt, alkylbetaine and derivatives thereof, imidazoline and derivatives thereof, and amphoteric antistatic agents such as alanine and derivatives thereof Nonionic antistatic agents such as agents, amino alcohols and derivatives thereof, glycerin and derivatives thereof, polyethylene glycol and derivatives thereof, and monomers having the above-mentioned cationic, anionic and zwitterionic ion conductive groups Examples thereof include ionic conductive polymers obtained by polymerization or copolymerization. These compounds may be used alone or in combination of two or more.

  Specifically, as a cation type antistatic agent, for example, quaternary ammonium group such as alkyltrimethylammonium salt, acyloylamidopropyltrimethylammonium methosulfate, alkylbenzylmethylammonium salt, acylcholine chloride, polydimethylaminoethyl methacrylate, etc. (Meth) acrylate copolymers having quaternary, styrene copolymers having quaternary ammonium groups such as polyvinylbenzyltrimethylammonium chloride, diallylamine copolymers having quaternary ammonium groups such as polydiallyldimethylammonium chloride, and the like. These compounds may be used alone or in combination of two or more.

  Examples of the anionic antistatic agent include alkyl sulfonate, alkyl benzene sulfonate, alkyl sulfate ester salt, alkyl ethoxy sulfate ester salt, alkyl phosphate ester salt, and sulfonic acid group-containing styrene copolymer. These compounds may be used alone or in combination of two or more.

  Examples of zwitterionic antistatic agents include alkylbetaines, alkylimidazolium betaines, and carbobetaine graft copolymers. These compounds may be used alone or in combination of two or more.

  Nonionic antistatic agents include, for example, fatty acid alkylolamide, di (2-hydroxyethyl) alkylamine, polyoxyethylene alkylamine, fatty acid glycerin ester, polyoxyethylene glycol fatty acid ester, sorbitan fatty acid ester, polyoxysorbitan fatty acid Examples thereof include esters, polyoxyethylene alkyl phenyl ethers, polyoxyethylene alkyl ethers, polyethylene glycols, polyoxyethylene diamines, copolymers composed of polyethers, polyesters and polyamides, and methoxypolyethylene glycol (meth) acrylates. These compounds may be used alone or in combination of two or more.

  Examples of the conductive polymer include polyaniline, polypyrrole, polythiophene and the like. These conductive polymers may be used alone or in combination of two or more.

  Examples of the conductive material include tin oxide, antimony oxide, indium oxide, cadmium oxide, titanium oxide, zinc oxide, indium, tin, antimony, gold, silver, copper, aluminum, nickel, chromium, titanium, iron, cobalt, Examples thereof include copper iodide, and alloys or mixtures thereof. These conductive materials may be used alone or in combination of two or more.

  As the resin component used for the antistatic resin and the conductive resin, for example, general-purpose resins such as polyester, acrylic, polyvinyl, urethane, melamine, and epoxy are used. In the case of a polymer type antistatic agent, it is not necessary to contain a resin component. Further, the antistatic resin component may contain a methylol- or alkylol-containing melamine-based, urea-based, glyoxal-based, acrylamide-based compound, epoxy compound, or isocyanate compound as a crosslinking agent.

  The antistatic layer can be formed by, for example, diluting the antistatic resin, conductive polymer, or conductive resin with a solvent such as an organic solvent or water, and applying and drying the coating liquid on a plastic film. Is done.

  Examples of the organic solvent used for forming the antistatic layer include methyl ethyl ketone, acetone, ethyl acetate, tetrahydrofuran, dioxane, cyclohexanone, n-hexane, toluene, xylene, methanol, ethanol, n-propanol, and isopropanol. can give. These solvents may be used alone or in combination of two or more.

  As a coating method in forming the antistatic layer, a known coating method is appropriately used. Specifically, for example, roll coating, gravure coating, reverse coating, roll brush, spray coating, air knife coating, impregnation and curtain coating are used. The law is raised.

  The thickness of the antistatic resin layer, the conductive polymer, and the conductive resin is usually about 0.01 to 5 μm, preferably about 0.03 to 1 μm.

  Examples of the method for depositing or plating the conductive material include vacuum deposition, sputtering, ion plating, chemical vapor deposition, spray pyrolysis, chemical plating, and electroplating.

  The thickness of the conductive material layer is usually 20 to 10,000 mm, preferably 50 to 5000 mm.

  As the kneading type antistatic agent, the above antistatic agent is appropriately used.

  The amount of the kneading type antistatic agent is 20% by weight or less, preferably 0.05 to 10% by weight, based on the total weight of the plastic film. The kneading method is not particularly limited as long as the antistatic agent can be uniformly mixed with the resin used for the plastic film. For example, a heating roll, a Banbury mixer, a pressure kneader, a biaxial kneader or the like is used. It is done.

  For plastic films, silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agents, release with silica powder, antifouling treatment, acid treatment, alkali treatment, primer treatment, corona Easy adhesion treatment such as treatment, plasma treatment, and ultraviolet treatment can also be performed.

  In the pressure-sensitive adhesive sheets of the present invention, a separator can be bonded to the pressure-sensitive adhesive surface for the purpose of protecting the pressure-sensitive adhesive surface as necessary. As a base material constituting the separator, there are paper and plastic film, but 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 film is usually about 5 to 200 μm, preferably about 10 to 100 μm. The adhesive layer bonding surface of the film is appropriately treated with a release agent such as a silicone, fluorine, long chain alkyl or fatty acid amide release agent, silica powder or the like.

  Examples and the like specifically showing the configuration and effects of the present invention will be described below. In addition, the evaluation item in an Example etc. measured as follows.

<Measurement of acid value>
The acid value was measured using an automatic titration apparatus (Hiranuma Sangyo Co., Ltd., COM-550), and was determined from the following formula.

A = {(Y−X) × f × 5.611} / M
A: Acid value Y: Titration volume of sample solution (ml)
X: Titration volume of a solution containing only 50 g of mixed solvent (ml)
f: Factor of titration solution M: Weight of polymer sample (g)

  The measurement conditions are as follows.

    Sample solution: About 0.5 g of a polymer sample was dissolved in 50 g of a mixed solvent (toluene / 2-propanol / distilled water = 50 / 49.5 / 0.5, weight ratio) to obtain a sample solution.

Titration solution: 0.1N, 2-propanol potassium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd., for petroleum product neutralization value test)
Electrode: Glass electrode; GE-101, Comparative electrode; RE-201
Measurement mode: Petroleum product neutralization number test 1

<Measurement of molecular weight>
The molecular weight was measured by using a GPC device (HLC-8220GPC) manufactured by Tosoh Corporation, and obtained in terms of polystyrene. The measurement conditions are as follows. Sample concentration: 0.2 wt% (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

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

Formula: 1 / (Tg + 273) = Σ [Wn / (Tgn + 273)]
[Wherein, Tg (° C.) is the glass transition temperature of the copolymer, Wn (−) is the weight fraction of each monomer, Tgn (° C.) is the glass transition temperature of the homopolymer of each monomer, and n is the type of each monomer Represents. ]
2-ethylhexyl acrylate: -70 ° C
Ethoxy-diethylene glycol acrylate: -70 ° C
2-hydroxyethyl acrylate: -15 ° C

<Measurement of glass transition temperature of acrylic polymers (F) and (G)>
The glass transition temperature Tg (° C.) of the obtained acrylic polymer (F) and acrylic polymer (G) was determined by dynamic viscoelasticity measurement according to the following procedure.

  A sheet of acrylic polymer having a thickness of 20 μm was laminated to a thickness of about 2 mm, and this was punched to φ7.9 mm to produce a cylindrical pellet, which was used as a sample for measuring the glass transition temperature (Tg). Using the above measurement sample, the measurement sample is fixed to a jig of 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 determined as the glass transition temperature Tg (° C.). The measurement conditions are as follows. That is, measurement: shear mode, temperature range: -70 ° C to 150 ° C, heating rate: 5 ° C / min, frequency: 1 Hz.

<NMR measurement>
NMR measurement was performed under the following measurement conditions using a nuclear magnetic resonance apparatus (EX-400, manufactured by JEOL Ltd.).

Observation frequency: 400 MHz ( ¹ H), 100 MHz ( ¹³ C)
Measuring solvent: actone-d ₆
Measurement temperature: 23 ° C

<XRF measurement>
XRF measurement was performed using a scanning X-ray fluorescence analyzer (manufactured by Rigaku Corporation, ZSX-100e) under the following measurement conditions.

Measuring method: filter paper method X-ray source: Rh

<FT-IR measurement>
The FT-IR measurement was performed under the following measurement conditions using an infrared spectrophotometer (manufactured by Nicolet, Magna-560).

Measuring method: ATR method Detector: DTGS
Resolution: 4.0 cm ⁻¹
Integration count: 64 times

<Measurement of peeling voltage>
The pressure-sensitive adhesive sheet is cut to a size of 70 mm in width and 130 mm in length, the separator is peeled off, and then a polarizing plate bonded to an acrylic plate (thickness: 1 mm, width: 70 mm, length: 100 mm) previously neutralized. Nitto Denko Corporation SEG1425EWVAGS2B, width: 70 mm, length: 100 mm) The surface was crimped by a hand roller so that one end protruded 30 mm.

  After leaving for one day in an environment of 23 ° C. × 50% RH, a sample is set at a predetermined position as shown in FIG. One end that protrudes 30 mm is fixed to an automatic winder, and is peeled off at a peeling angle of 150 ° and a peeling speed of 10 m / min. The potential of the polarizing plate surface generated at this time was measured with a potential measuring device (KSD-0103, manufactured by Kasuga Denki Co., Ltd.) fixed at a predetermined position. The measurement was performed in an environment of 23 ° C. × 50% RH.

<Evaluation of contamination>
The pressure-sensitive adhesive sheet is cut to a size of 30 mm in width and 80 mm in length, the separator is peeled off, and then bonded to a polarizing plate (manufactured by Nitto Denko Corporation, SEG1425WVAGS2B, width: 70 mm, length: 100 mm) with a hand roller. Produced.

  After leaving the evaluation sample in an environment of 50 ° C. × 92% RH for 24 hours, the pressure-sensitive adhesive sheet was peeled from the adherend by hand, and the contamination state of the adherend surface at that time was visually observed. The evaluation criteria are as follows.

If no contamination was found: ○
If contamination is found: ×

<Adhesion measurement>
A triacetyl cellulose film (Fuji Film, Fujitac, thickness: 90 μm) was cut into a width of 70 mm and a length of 100 mm, immersed in an aqueous solution of sodium hydroxide (10% by weight) at 60 ° C. for 1 minute, and then with distilled water. Washed to prepare an adherend.

  After the adherend was allowed to stand in an environment of 23 ° C. × 50% RH for 24 hours, an adhesive sheet cut to a width of 25 mm and a length of 100 mm was laminated to the adherend at a pressure of 0.25 MPa, and an evaluation sample was prepared. Produced. After laminating, the film was left in an environment of 23 ° C. × 50% RH for 30 minutes, and then the adhesive strength when peeled at a peeling speed of 10 m / min and a peeling angle of 180 ° was measured with a universal tensile tester. The measurement was performed in an environment of 23 ° C. × 50% RH.

<Preparation of (meth) acrylic polymer>
(Acrylic polymer (A))
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, a condenser, and a dropping funnel, 140 parts by weight of 2-ethylhexyl acrylate, 60 parts by weight of ethoxy-diethylene glycol acrylate, 8 parts by weight of 2-hydroxyethyl acrylate, As a polymerization initiator, 0.4 part by weight of 2,2′-azobisisobutyronitrile, 94 parts by weight of toluene, and 218 parts by weight of ethyl acetate were charged, and nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was Was kept at around 65 ° C. for 6 hours to prepare an acrylic polymer (A) solution (40% by weight). This acrylic polymer (A) had Tg = −68 ° C., a weight average molecular weight of 500,000, and an acid value of 0.0.

(Acrylic polymer (B))
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a condenser, and a dropping funnel, 200 parts by weight of ethoxy-diethylene glycol acrylate, 12 parts by weight of 2-hydroxyethyl acrylate, and 2,2 ′ as a polymerization initiator -0.4 parts by weight of azobisisobutyronitrile, 197 parts by weight of toluene, and 197 parts by weight of ethyl acetate were charged, nitrogen gas was introduced with gentle stirring, and the liquid temperature in the flask was kept at around 65 ° C. A time polymerization reaction was carried out to prepare a solution (35% by weight) of an acrylic polymer (B). This acrylic polymer (B) had Tg = −68 ° C., a weight average molecular weight of 430,000, and an acid value of 0.0.

(Acrylic polymer (C))
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a condenser, and a dropping funnel, 200 parts by weight of 2-ethylhexyl acrylate, 8 parts by weight of 2-hydroxyethyl acrylate, 2,2 ′ as a polymerization initiator -Charge 0.4 parts by weight of azobisisobutyronitrile and 312 parts by weight of ethyl acetate, introduce nitrogen gas while gently stirring, and perform a polymerization reaction for 6 hours while maintaining the liquid temperature in the flask at around 65 ° C. A solution (40% by weight) of an acrylic polymer (C) was prepared. This acrylic polymer (C) had Tg = −68 ° C., a weight average molecular weight of 500,000, and an acid value of 0.0.

(Acrylic polymer (D))
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a condenser, and a dropping funnel, 190 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of ethoxy-diethylene glycol acrylate, 8 parts by weight of 2-hydroxyethyl acrylate, As a polymerization initiator, 0.4 part by weight of 2,2′-azobisisobutyronitrile and 312 parts by weight of ethyl acetate were charged, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was kept at around 65 ° C. The polymerization reaction was carried out for 6 hours, and an acrylic polymer (D) solution (40% by weight) was prepared. This acrylic polymer (D) had Tg = −68 ° C., a weight average molecular weight of 680,000, and an acid value of 0.0.

(Acrylic polymer (E))
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a condenser, and a dropping funnel, 180 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of ethoxy-diethylene glycol acrylate, 8 parts by weight of 2-hydroxyethyl acrylate, As a polymerization initiator, 0.4 part by weight of 2,2′-azobisisobutyronitrile, 47 parts by weight of toluene, and 265 parts by weight of ethyl acetate were charged, and nitrogen gas was introduced while gently stirring. Was kept at around 65 ° C. for 6 hours to prepare a solution (40% by weight) of an acrylic polymer (E). This acrylic polymer (E) had Tg = −68 ° C., a weight average molecular weight of 510,000, and an acid value of 0.0.

(Acrylic polymer (F))
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel, 199 parts by weight of 2-ethylhexyl acrylate, methoxypolyethylene glycol monoacrylate (manufactured by NOF Corporation, Blemmer PME-1000, EO) Addition number of moles: 23) 1 part by weight, 2-hydroxyethyl acrylate 8 parts by weight, 2,2′-azobisisobutyronitrile 0.4 part by weight as polymerization initiator, ethyl acetate 387 parts by weight Nitrogen gas was introduced while stirring, and the polymerization temperature was kept at around 65 ° C. for 6 hours to prepare a solution (35% by weight) of an acrylic polymer (F). This acrylic polymer (F) had Tg = 0 ° C. or less, a weight average molecular weight of 490,000, and an acid value of 0.0.

(Acrylic polymer (G))
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel, 199.4 parts by weight of 2-ethylhexyl acrylate, methoxypolyethylene glycol monoacrylate (manufactured by NOF Corporation, Blemmer PME-1000) EO addition mole number about 23) 0.6 part by weight, 2-hydroxyethyl acrylate 8 part by weight, 2,2′-azobisisobutyronitrile 0.4 part by weight as polymerization initiator, ethyl acetate 387 part by weight The mixture was charged and nitrogen gas was introduced while gently stirring, and the polymerization temperature was maintained at around 65 ° C. for 6 hours to prepare a solution (35% by weight) of an acrylic polymer (G). This acrylic polymer (G) had Tg = 0 ° C. or less, a weight average molecular weight of 490,000, and an acid value of 0.0.

<Preparation of ionic liquid (a)>
After adding 20 wt% aqueous solution of 10 parts by weight of 1-butyl-3-methylimidazolium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) to a four-necked flask equipped with a stirring blade, a thermometer and a condenser, While rotating, a 20 wt% aqueous solution of 19 parts by weight of lithium bis (trifluoromethanesulfonyl) imide (manufactured by Kishida Chemical Co., Ltd.) was gradually added. After the addition, stirring was continued at room temperature (25 ° C.) for 2 hours, and then allowed to stand for 12 hours, and the supernatant was removed to obtain a liquid product.

The obtained liquid product was washed with 200 parts by weight of distilled water three times and dried under an environment of 110 ° C. for 2 hours to obtain 20 parts by weight of ionic liquid (a). The obtained ionic liquid (a) is subjected to NMR ( ¹ H, ¹³ C) measurement, FT-IR measurement, and XRF measurement to be 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide. Identification / confirmation.

<Preparation of ionic liquid (b)>
A solution obtained by diluting 10 parts by weight of 1-butyl-3-methylpyridinium chloride (manufactured by Wako Pure Chemical Industries, Ltd.) to 20% by weight with distilled water in a four-necked flask equipped with a stirring blade, a thermometer, and a condenser. Then, a solution obtained by diluting 19 parts by weight of lithium bis (trifluoromethanesulfonyl) imide (manufactured by Kishida Chemical Co., Ltd.) to 20% by weight with distilled water was gradually added while rotating the stirring blade. After the addition, stirring was continued at 25 ° C. for 2 hours, and then allowed to stand for 12 hours, and the supernatant was removed to obtain a liquid product.

The obtained liquid product was washed three times with 200 parts by weight of distilled water and dried at a temperature of 110 ° C. for 2 hours to obtain 20 parts by weight of ionic liquid (b). The obtained ionic liquid (b) is subjected to NMR ( ¹ H, ¹³ C) measurement, FT-IR measurement, and XRF measurement to identify 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide. ·confirmed.

<Preparation of antistatic agent>
[Antistatic agent solution (a)]
In a four-necked flask equipped with a stirring blade, a thermometer, and a condenser, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical Co., 25 ° C.) 5 parts by weight of a nonionic reactive surfactant (Asahi Denka Kogyo Co., Ltd., Adekaria Soap NE-10) and 90 parts by weight of ethyl acetate were charged. The antistatic agent solution (a) (10% by weight) was prepared by mixing and stirring for 30 minutes while maintaining the temperature around 25 ° C.

[Antistatic agent solution (b)]
In a four-necked flask equipped with a stirring blade, a thermometer, and a condenser, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical Co., 25 ° C.) 5 parts by weight of a nonionic reactive surfactant (Asahi Denka Kogyo Co., Ltd., Adekaria Soap ER-10) and 90 parts by weight of ethyl acetate were charged. The mixture was stirred at 30 ° C. for about 30 minutes to prepare an antistatic agent solution (b) (10% by weight).

[Antistatic agent solution (c)]
A four-necked flask equipped with a stirring blade, a thermometer and a condenser was charged with 90 parts by weight of isopropyl alcohol in 10 parts by weight of lauryltrimethylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd., solid at 25 ° C.), and the liquid temperature in the flask Was kept at room temperature (25 ° C.) and mixed and stirred for 30 minutes to prepare an antistatic agent solution (c) (10% by weight).

[Antistatic agent solution (d)]
A cationic surfactant lauryltrimethylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd., solid at 25 ° C.), 10 parts by weight, 20 parts by weight of ethyl acetate and 20 parts by weight of isopropyl alcohol is diluted with an antistatic agent solution (d ) (20 wt%) was prepared.

[Antistatic agent solution (e)]
A four-necked flask equipped with a stirring blade, thermometer, and condenser is charged with 0.2 parts by weight of lithium perchlorate, 9.8 parts by weight of polypropylene glycol (diol type, number average molecular weight 2000), and 10 parts by weight of ethyl acetate. The mixture was stirred for about 2 hours while maintaining the liquid temperature in the flask at around 80 ° C. to prepare an antistatic agent solution (e) (50% by weight).

<Preparation of antistatic treatment film>
Antistatic by diluting 10 parts by weight of an antistatic agent (manufactured by Solvex, Microsolver RMd-142, mainly composed of tin oxide and polyester resin) with a mixed solvent consisting of 30 parts by weight of water and 70 parts by weight of methanol An agent solution was prepared.

  The obtained antistatic agent solution was applied onto a polyethylene terephthalate (PET) film (thickness 38 μm) using a Meyer bar and dried at 130 ° C. for 1 minute to remove the solvent and remove the antistatic layer (thickness). 0.2 μm) to form an antistatic film.

[Example 1]
(Preparation of adhesive composition)
The acrylic polymer (A) solution (40% by weight) was diluted to 20% by weight with ethyl acetate, and 100 parts by weight of this solution was diluted with 1-hexyl-3-methylimidazolium trifluoromethanesulfonate (manufactured by ACROS ORGANICS, 25 0.2 parts by weight of a liquid at 0 ° C, isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX), 0.4 parts of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst An acrylic pressure-sensitive adhesive solution (1) was prepared by adding parts by weight and mixing and stirring at room temperature (25 ° C.) for about 1 minute.

(Preparation of adhesive sheet)
The said acrylic adhesive solution (1) was apply | coated to the surface opposite to the antistatic process surface of said antistatic process film, and it heated at 110 degreeC for 3 minute (s), and formed the 20-micrometer-thick adhesive layer. Next, a silicone-treated surface of a polyethylene terephthalate film having a thickness of 25 μm having one surface subjected to silicone treatment was bonded to the surface of the pressure-sensitive adhesive layer to produce a pressure-sensitive adhesive sheet.

[Example 2]
(Preparation of adhesive composition)
The acrylic polymer (A) solution (40% by weight) is diluted to 20% by weight with ethyl acetate, and 100 parts by weight of the solution is added with 0.3 parts by weight of the ionic liquid (a) (liquid at 25 ° C.), 0.4 part by weight of isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) and 0.4 part by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst were added at room temperature (25 ° C. The mixture was stirred for about 1 minute to prepare an acrylic pressure-sensitive adhesive solution (2).

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution (2) was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 3
(Preparation of adhesive composition)
Instead of 0.3 parts by weight of the ionic liquid (a), N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical Co., 25 ° C.) Acrylic pressure-sensitive adhesive solution (3) was prepared in the same manner as in Example 2 except that 0.3 part by weight was used.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution (3) was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 4
(Preparation of adhesive composition)
A solution (35% by weight) of the acrylic polymer (B) was diluted to 20% by weight with ethyl acetate, and 1-hexyl-3-methylimidazolium trifluoromethanesulfonate (manufactured by ACROS ORGANICS, 25 1.2 parts by weight of a liquid at ℃, isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX), 0.4 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst An acrylic adhesive solution (4) was prepared by adding parts by weight and mixing and stirring at room temperature (25 ° C.) for about 1 minute.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1, except that the acrylic pressure-sensitive adhesive solution (4) was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 5
(Preparation of adhesive composition)
The acrylic polymer (A) solution (40% by weight) is diluted to 20% by weight with ethyl acetate, and the antistatic agent (a) solution (10% by weight) 6.0 parts by weight is added to 100 parts by weight of the solution. 0.5 parts by weight of isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) and 0.4 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst were added at room temperature (25 ° C. The mixture was stirred for about 1 minute to prepare an acrylic pressure-sensitive adhesive solution (5).

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution (5) was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 6
(Preparation of adhesive composition)
Example 5 except that 6.0 parts by weight of the antistatic agent (b) solution (10% by weight) was used instead of 6.0 parts by weight of the antistatic agent (a) solution (10% by weight). In the same manner as above, an acrylic pressure-sensitive adhesive solution (6) was prepared.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution (6) was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 7
(Preparation of adhesive composition)
A solution (40% by weight) of the acrylic polymer (A) is diluted to 20% by weight with ethyl acetate, and 0.3 parts by weight of the ionic liquid (b) (liquid at 25 ° C.) is added to 100 parts by weight of the solution. , 0.4 parts by weight of isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) and 0.4 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst were added at room temperature (25 The acrylic pressure-sensitive adhesive solution was prepared by mixing and stirring for about 1 minute.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 8
(Preparation of adhesive composition)
A solution (40% by weight) of the acrylic polymer (D) is diluted to 20% by weight with ethyl acetate, and 0.2 parts by weight of the ionic liquid (b) (liquid at 25 ° C.) is added to 100 parts by weight of the solution. , 0.4 parts by weight of isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) and 0.4 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst were added at room temperature (25 The acrylic pressure-sensitive adhesive solution was prepared by mixing and stirring for about 1 minute.

(Preparation of adhesive sheet)
The said acrylic adhesive solution was apply | coated to the surface opposite to the antistatic process surface of said antistatic process film, and it heated at 110 degreeC for 3 minute (s), and formed the 20-micrometer-thick adhesive layer. Next, a silicone-treated surface of a polyethylene terephthalate film having a thickness of 25 μm having one surface subjected to silicone treatment was bonded to the surface of the pressure-sensitive adhesive layer to produce a pressure-sensitive adhesive sheet.

Example 9
In Example 8, the same method as in Example 8 was used, except that the acrylic polymer (E) solution (40 wt%) was used instead of the acrylic polymer (D) solution (40 wt%). An acrylic pressure-sensitive adhesive solution was prepared, and a pressure-sensitive adhesive sheet was produced by the same method as in Example 8.

Example 10
In Example 8, the same method as in Example 8 was used, except that the acrylic polymer (F) solution (35% by weight) was used instead of the acrylic polymer (D) solution (40% by weight). An acrylic pressure-sensitive adhesive solution was prepared, and a pressure-sensitive adhesive sheet was produced by the same method as in Example 8.

Example 11
In Example 8, the same method as in Example 8 was used except that the solution (35% by weight) of the acrylic polymer (G) was used instead of the solution (40% by weight) of the acrylic polymer (D). An acrylic pressure-sensitive adhesive solution was prepared, and a pressure-sensitive adhesive sheet was produced by the same method as in Example 8.

[Comparative Example 1]
(Preparation of adhesive composition)
A solution (40% by weight) of the acrylic polymer (C) was diluted to 20% by weight with ethyl acetate, and 1-hexyl-3-methylimidazolium trifluoromethanesulfonate (manufactured by ACROS ORGANICS, 25) was added to 100 parts by weight of this solution. 0.1 parts by weight of a liquid at 0 ° C., 0.8 parts by weight of isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX), dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst 4 parts by weight was added, and mixed and stirred at room temperature (25 ° C.) for about 1 minute to prepare an acrylic pressure-sensitive adhesive solution (7).

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution (7) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 2]
(Preparation of adhesive composition)
A solution (40% by weight) of the acrylic polymer (C) is diluted to 20% by weight with ethyl acetate, 0.2 parts by weight of the ionic liquid (a) is added to 100 parts by weight of this solution, and isocyanurate of hexamethylene diisocyanate. 0.4 parts by weight of a body (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) and 0.4 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a cross-linking catalyst were added at room temperature (25 ° C.) for about 1 minute. Mixing and stirring were performed to prepare an acrylic pressure-sensitive adhesive solution (8).

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution (8) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 3]
(Preparation of adhesive composition)
Instead of 0.2 parts by weight of the ionic liquid (a), N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical Co., 25 ° C.) Acrylic pressure-sensitive adhesive solution (9) was prepared in the same manner as in Comparative Example 2 except that 0.2 parts by weight were used.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution (9) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 4]
(Preparation of adhesive composition)
Instead of 0.2 parts by weight of the above N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical Co., Inc., liquid at 25 ° C.), N, N Comparative Example 3 except that 0.02 part by weight of diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical Co., Inc., liquid at 25 ° C.) was used Similarly, an acrylic pressure-sensitive adhesive solution (10) was prepared.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution (10) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 5]
(Preparation of adhesive composition)
An acrylic adhesive was used in the same manner as in Example 2 except that 10.0 parts by weight of the antistatic agent (c) solution (10% by weight) was used instead of 0.3 parts by weight of the ionic liquid (a). An agent solution (11) was prepared.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution (11) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 6]
(Preparation of adhesive composition)
A solution (40% by weight) of the acrylic polymer (C) is diluted to 20% by weight with ethyl acetate, and 0.2 parts by weight of the ionic liquid (b) (liquid at 25 ° C.) is added to 100 parts by weight of the solution. , 0.4 parts by weight of isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) and 0.4 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst were added at room temperature (25 The acrylic pressure-sensitive adhesive solution was prepared by mixing and stirring for about 1 minute.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 7]
In Example 8, an acrylic pressure-sensitive adhesive solution was prepared by the same method as in Example 8 except that 0.2 parts by weight of the ionic liquid (b) was not used, and the same method as in Example 8 was used. Thus, an adhesive sheet was prepared.

[Comparative Example 8]
In Example 9, an acrylic adhesive solution was prepared by the same method as in Example 9 except that 0.2 parts by weight of the ionic liquid (b) was not used, and the same method as in Example 8 was used. Thus, an adhesive sheet was prepared.

[Comparative Example 9]
In Comparative Example 6, Comparative Example 6 was used except that 1.0 part by weight of the antistatic agent (d) solution (20% by weight) was used instead of 0.2 part by weight of the ionic liquid (b). An acrylic pressure-sensitive adhesive solution was prepared by the same method as described above, and a pressure-sensitive adhesive sheet was prepared by the same method as in Comparative Example 6 using this solution.

[Comparative Example 10]
(Preparation of adhesive composition)
The acrylic polymer (C) solution (40% by weight) was diluted to 20% by weight with ethyl acetate, and 4 parts by weight of the antistatic agent solution (e) (50% by weight) was added to 100 parts by weight of this solution. Add 0.53 parts by weight of trimethylolpropane / tolylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate L) and 0.4 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst. The mixture was stirred for about 1 minute at room temperature (25 ° C.) to prepare an acrylic pressure-sensitive adhesive solution.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution was used instead of the acrylic pressure-sensitive adhesive solution (1).

  About the adhesive sheet obtained by said Example, comparative example, etc., the stripping voltage, the contamination | pollution property, and adhesive force were evaluated in said way. The results are shown in Table 1.

上記表１の結果により、本発明にしたがって作製された粘着剤組成物を用いた場合（実施例１〜１１）、全実施例において偏光板への剥離帯電圧が抑制され、かつ、偏光板への汚染の発生もないことが明らかとなった。

According to the results of Table 1 above, when the pressure-sensitive adhesive composition prepared according to the present invention was used (Examples 1 to 11), the stripping voltage to the polarizing plate was suppressed in all the examples, and to the polarizing plate. It became clear that there was no pollution.

  On the other hand, when (meth) acrylic polymer uses the adhesive composition which does not contain the (meth) acrylic-acid alkylene oxide as a monomer unit (Comparative Examples 1-3, 6), and an antistatic agent In Comparative Examples 5 and 9 using a cationic surfactant as a sample, although the stripping voltage was suppressed, the occurrence of contamination was observed. Further, in Comparative Example 4 where the amount of the antistatic agent was reduced in the pressure-sensitive adhesive composition in which the (meth) acrylic polymer did not contain (meth) acrylic acid alkylene oxide as a monomer unit, no occurrence of contamination was observed. As a result, the stripping voltage increased. Moreover, in Comparative Examples 7-8 which does not use an ionic liquid, it resulted in a peeling strip voltage becoming high. Furthermore, in Comparative Example 10 using an antistatic agent comprising a polyether polyol and an alkali metal salt, contamination occurred due to bleeding. Therefore, in all the comparative examples, it was impossible to achieve both suppression of the peeling voltage to the polarizing plate as the adherend and suppression of the occurrence of contamination.

Schematic configuration diagram of potential measurement unit used for measurement of peeling voltage in Examples etc.

Claims (8)

  An adhesive composition comprising an ionic liquid and a (meth) acrylic polymer having 0.1 to 100% by weight of (meth) acrylic acid alkylene oxide as a monomer unit.   The pressure-sensitive adhesive composition according to claim 1, wherein the ionic liquid is at least one of a nitrogen-containing onium salt, a sulfur-containing onium salt, and a phosphorus-containing onium salt. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the ionic liquid contains one or more cations represented by the following general formulas (A) to (D).

[R _a in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms and may include a hetero atom, and R _b and R _c may be the same or different, and may be hydrogen or _C 1 to 16 carbon atoms. It represents a hydrocarbon group and may contain 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 contain a hetero atom, and R _e , R _f , and R _g are the same or different and represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[R _h in the formula (C) represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a hetero atom, and R _i , R _j , and R _k may be the same or different and each may represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[Z in 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. , And may contain a heteroatom. However, when Z is a sulfur atom, there is no _Ro . ]   The pressure-sensitive adhesive composition according to any one of claims 1 to 3, comprising an ethylene oxide group-containing compound.   The pressure-sensitive adhesive composition according to claim 4, wherein the ethylene oxide group-containing compound is a surfactant having an ethylene oxide group.   The adhesive layer formed by bridge | crosslinking the adhesive composition in any one of Claims 1-5.   A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition according to claim 1 on one side or both sides on a support. A pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition according to any one of claims 1 to 5 is formed on one side or both sides on a support made of a plastic substrate subjected to antistatic treatment. Characteristic surface protective film.

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