JP4800018B2 - Adhesive composition, adhesive sheet and surface protective film - Google Patents

Description

  The present invention relates to an antistatic pressure-sensitive adhesive composition, and an antistatic pressure-sensitive adhesive sheet and a surface protective film formed into a sheet form or a tape form 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. In particular, 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 capable of preventing electrification at the time of peeling of an adherend that is not antistatic, reducing contamination on the adherend, and preventing floating from the adherend. An object is to provide a pressure-sensitive adhesive composition having excellent reliability, 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 a polymer having a nitrogen-containing monomer of 0.5 to 30% by weight as a monomer unit and a glass transition temperature Tg of 0 ° C. or less, and an ionic liquid. It is characterized by.

  According to the pressure-sensitive adhesive composition of the present invention, as shown in the results of Examples, a polymer having 0.5 to 30% by weight of a nitrogen-containing monomer as a monomer unit and having a glass transition temperature Tg of 0 ° C. or lower. Is a base polymer, and further contains an ionic liquid, the cross-linked pressure-sensitive adhesive layer has reduced anti-staining properties to the protected body and excellent antistatic properties when peeled. Although the details of the reason why such a crosslinked product of the polymer and the ionic liquid exhibits such characteristics are not clear, it is difficult to bleed the ionic liquid by coordinating the ionic liquid to the nitrogen atom of the nitrogen-containing monomer. It is presumed that the antistatic property and the low pollution property are realized side by side.

  In addition, 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 present invention, the ionic liquid refers to a molten salt (ionic compound) that exhibits a liquid state at room temperature (25 ° C.).

  The pressure-sensitive adhesive composition of the present invention uses the above ionic liquid as an antistatic agent to suppress bleeding of the antistatic agent, and has excellent adhesion reliability to an adherend even over time or at high temperatures. It becomes. The reason why bleeding is suppressed by using an ionic liquid is not clear, but since the ionic liquid exhibits excellent conductivity by itself, sufficient antistatic ability can be obtained even if the surface of the adherend is traced. It is estimated that.

  In the pressure-sensitive adhesive composition of the present invention, a polymer having 0.5 to 30% by weight of a nitrogen-containing monomer as a monomer unit and having a glass transition temperature Tg of 0 ° C. or less is used as a base polymer.

  Further, the nitrogen-containing monomer in the present invention refers to a polymerizable monomer containing one or more nitrogen atoms in the monomer structure. Examples thereof include amide group-containing monomers, amino group-containing monomers, imide group-containing monomers, cyano group-containing monomers, acryloylmorpholine, and the like.

  In the above, the ionic liquid is preferably 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.

[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 _C 16. Represents a hydrocarbon group and may contain heteroatoms. 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 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 heteroatoms. However, when Z is a sulfur atom, there is no _Ro . ]

  Furthermore, the polymer is preferably a (meth) acrylic polymer having as a main component at least one (meth) acrylate having an alkyl group having 1 to 14 carbon atoms. These (meth) acrylic polymers provide a good balance of compatibility with the ionic liquid and the base polymer, and can sufficiently maintain the adhesive properties.

  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.

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

  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 contains a polymer having 0.5 to 30% by weight of a nitrogen-containing monomer as a monomer unit, and a glass transition temperature Tg of 0 ° C. or less, and an ionic liquid. It is characterized by that.

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

  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.

[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 _C 16. Represents a hydrocarbon group and may contain heteroatoms. 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 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 heteroatoms. 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 pyrazolinium 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, for example, tetramethylammonium cation, tetraethylammonium cation, tetrapropylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, tetraheptylammonium cation, trimethylheptylammonium cation, trimethyldecylammonium cation , Triethylmethylammonium cation, triethylpropylammonium cation, triethylpentylammonium cation, triethylhexylammonium cation, triethylheptylammonium cation, tributylethylammonium cation, tripentylbutylammonium cation, trihexylmethylammonium cation, Lihexylpentylammonium cation, triheptylmethylammonium cation, triheptylhexylammonium cation, trioctylmethylammonium cation, glycidyltrimethylammonium cation, diallyldimethylammonium cation, N, N-dimethyl-N, N-dipropylammonium cation, N , N-dimethyl-N, N-dihexylammonium cation, N, N-dipropyl-N, N-dihexylammonium 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- To ethyl-N- Ptyl ammonium cation, N, N-dimethyl-N-ethyl-N-nonyl ammonium cation, N, N-dimethyl-N-propyl-N-butyl ammonium cation, N, N-dimethyl-N-propyl-N-pentyl ammonium Cation, N, N-dimethyl-N-propyl-N-hexylammonium cation, N, N-dimethyl-N-propyl-N-heptylammonium cation, N, N-dimethyl-N-butyl-N-hexyl Ammonium cation, N, N-dimethyl-N-butyl-N-heptylammonium cation, N, N-dimethyl-N-pentyl-N-hexylammonium cation, N, N-dimethyl-N-hexyl-N- Heptylammonium cation, N, N-diethyl-N-methyl-N-propylammonium cation, N, N-diethyl-N-methyl-N-pentylammo Cation, N, N-diethyl-N-methyl-N-heptylammonium cation, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, N, N-diethyl-N-propyl- N-pentylammonium cation, N, N-dipropyl-N-methyl-N-ethylammonium cation, N, N-dipropyl-N-methyl-N-pentylammonium cation, N, N-dipropyl-N-butyl-N- Hexyl ammonium cation, N, N-dibutyl-N-methyl-N-pentyl ammonium cation, N, N-dibutyl-N-methyl-N-hexyl ammonium cation, N-methyl-N-ethyl-N-propyl- N-pentylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, Trihexylsulfonium cation, dimethyldecylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrapentylphosphonium cation, tetrahexylphosphonium cation, tetraheptylphosphonium cation, tetra Examples thereof include octylphosphonium cation, trimethyldecylphosphonium cation, triethylmethylphosphonium cation, and tributylethylphosphonium cation. Among them, trimethylheptylammonium cation, trimethyldecylammonium cation, triethylmethylammonium cation, triethylpropylammonium cation, triethylpentylammonium cation, triethylhexylammonium cation, triethylheptylammonium cation, tributylethylammonium cation, tripentylbutylammonium cation, trihexyl Methylammonium cation, trihexylpentylammonium cation, triheptylmethylammonium cation, triheptylhexylammonium cation, trioctylmethylammonium 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-butylammonium cation, N, N-dimethyl-N-propyl-N-pentylammonium cation, N, N-dimethyl-N-propyl-N-hexylammonium cation, N, N-dimethyl-N-propyl-N-heptylammonium cation, N, N-dimethyl-N-butyl-N-hexylammonium cation, N, N-dimethyl-N-butyl-N-heptylammonium cation, N, N-dimethyl-N- N-Nyl-hexylammonium cation, N, N-dimethyl-N-hexyl-N-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-methyl-N- (2-methoxyethyl) ammonium cation, N, N -Diethyl-N-propyl-N-pentylammonium 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 cations such as methyl-N-hexylammonium cation, N-methyl-N-ethyl-N-propyl-N-pentylammonium cation, dimethyldecylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, etc. Asymmetric tetraalkylphosphonium cations such as trimethylsulfonium cation, trimethyldecylphosphonium cation, triethylmethylphosphonium cation, and tributylethylphosphonium 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) methide, 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 Ru-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 (trifluoro) Lomethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-heptylammonium bis (trifluoromethanesulfonyl) 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, Triethylpropylammonium 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 Bis (trifluoromethanesulfonyl) imide, N, N-dibutyl-N-methyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, trioctylmethylammonium bis (trifluoromethanesulfonyl) imide, N-methyl-N-ethyl- And N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide.

  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.] A halide method, a hydroxide method, an acid ester method, a complex formation method, a 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. 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).

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.

The acid ester method is a method performed by reactions as shown in (9) to (11). First, a tertiary amine (R ₃ N) is reacted with an acid ester to obtain an acid ester product (Reaction Formula (9)). As the acid ester, inorganic acids such as sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid, and carbonic acid are used. And esters of organic acids such as esters, methanesulfonic acid, methylphosphonic acid, formic acid, etc.).

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.

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)).

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

  R in the 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 polymer to be used and the ionic liquid, but is generally 0.01 to 40 weights with respect to 100 parts by weight of the base polymer. Parts, preferably 0.01 to 30 parts by weight, more preferably 0.03 to 20 parts by weight, still more preferably 0.03 to 10 parts by weight, particularly preferably 0.03 to 4.9 parts by weight, 0.05-3 parts by weight is most preferred. 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.

  In the present invention, a polymer having 0.5 to 30% by weight of a nitrogen-containing monomer as a monomer unit and having a glass transition temperature Tg of 0 ° C. or lower is used as the base polymer.

  The polymer used in the present invention is not particularly limited as long as it has a tackiness corresponding to those described above.

  Specific examples of the nitrogen-containing monomer in the present invention include, for example, an amide group-containing monomer, an amino group-containing monomer, an imide group-containing monomer, a cyano group-containing monomer, and acryloylmorpholine.

  Examples of the amide group-containing monomer include acrylamide, methacrylamide, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, N-diethylmethacrylamide, N-isopropylacrylamide, N -Methylolacrylamide, diacetone acrylamide, N-vinylacetamide, N, N'-methylenebisacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminopropylmethacrylamide, N-vinylpyrrolidone, N-vinylcaprolactam Etc.

  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 N-isopropylmaleimide, N-cyclohexylmaleimide, and itaconimide.

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

  The nitrogen-containing monomer may be used alone or in combination of two or more, but is preferably 0.5 to 30% by weight in the monomer component of the polymer, 25% by weight is more preferable, and 2 to 20% by weight is particularly preferable. When the content of the nitrogen-containing monomer is less than 0.5% by weight, the effect of suppressing bleeding of the ionic liquid and the effect of reducing contamination of the protected object may not be obtained, which is not preferable. On the other hand, when the content of the nitrogen-containing monomer is more than 30% by weight, the adhesive strength of the pressure-sensitive adhesive composition is increased, and particularly when it is used as a surface protective film, it causes damage to the adherend during peeling. Is not preferable.

  Moreover, although the glass transition temperature (Tg) of the said polymer is 0 degrees C or less normally as a base polymer, it is preferable that it is -100 degreeC--5 degreeC, and it is -80 degreeC--10 degreeC. Is more preferable. When the glass transition temperature is higher than 0 ° C., it may be difficult to obtain sufficient adhesive force. In addition, the glass transition temperature (Tg) of a base polymer can be adjusted in the said range by changing the monomer component and composition ratio to be used suitably.

  Examples of such a polymer include (meth) acrylic polymers, natural rubber, styrene-isoprene-styrene block copolymer mainly containing one or more of (meth) acrylates having 1 to 14 carbon atoms. Polymer (SIS block copolymer), Styrene-butadiene-styrene block copolymer (SBS block copolymer), Styrene-ethylene-butylene-styrene block copolymer (SEBS block copolymer), Styrene-butadiene rubber, Polymers generally applied as the adhesive polymer such as polybutadiene, polyisoprene, polyisobutylene, butyl rubber, chloroprene rubber, and silicone rubber are listed.

  Among these, the main component is one or more of (meth) acrylates having an alkyl group having 1 to 14 carbon atoms because a balance of compatibility with an ionic liquid and excellent adhesive properties can be obtained ( A (meth) acrylic polymer is preferably used.

  The (meth) acrylic polymer having one or more of (meth) acrylates having an alkyl group having 1 to 14 carbon atoms as a main component has an alkyl group having 1 to 14 carbon atoms (meth) ) A (meth) acrylic polymer whose main component is a monomer containing 50 to 99.5% by weight of one or more acrylates is preferred.

  Specific examples of the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and s-butyl (meth) acrylate. , T-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate , Isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, and the like.

  Especially, when using for the surface protection film of this invention, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate , Isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, etc. A (meth) acrylate having 14 alkyl groups is preferably used. By using a (meth) acrylic polymer comprising a (meth) acrylate having an alkyl group having 6 to 14 carbon atoms, it becomes easy to control the adhesive force to the adherend to be low and has excellent removability. It will be a thing.

  In addition, as another polymerizable monomer component, Tg is 0 ° C. or lower (usually −100 ° C. or higher) for easy balance of adhesion performance, and the glass transition point of (meth) acrylic polymer A polymerizable monomer for adjusting the releasability can be used within a range not impairing the effects of the present invention.

  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, vinyl esters, aromatic vinyl compounds, carboxyl group-containing monomers, acids A component having a functional group that functions as an adhesive strength improvement or crosslinking base, such as an anhydride group-containing monomer, a hydroxyl group-containing monomer, an epoxy group-containing monomer, or a vinyl ether can be used as appropriate. These other components may be used alone or in combination of two or more.

  However, when using a (meth) acrylate 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 acid value of the (meth) acrylic polymer to be 29 or less. . When the acid value of the (meth) acrylic polymer exceeds 29, the antistatic property tends to deteriorate. Furthermore, when applying to a surface protection film, it is preferable to adjust so that the acid value of a (meth) acrylic-type polymer may become 1 or less. When the acid value of the (meth) acrylic polymer exceeds 1, the adhesive strength with time tends to increase.

  The acid value can be adjusted by adjusting the amount of (meth) acrylate having an acid functional group. For example, 2-ethylhexyl acrylate and acrylic acid are copolymerized as a (meth) acrylic polymer having a carboxyl group (meth) ) Acrylic polymer can be mentioned. In this case, the acid value is adjusted 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. Can be satisfied.

  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 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, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, Examples include diethylene glycol monovinyl ether.

  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 0.1 to 20 parts by weight and more preferably 0.5 to 10 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 is lowered, the wetting to the polarizing plate becomes insufficient, and it tends to cause peeling. A weight average molecular weight means what was obtained by measuring by GPC (gel permeation chromatography).

  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. Moreover, the polymer obtained may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

  In the pressure-sensitive adhesive composition of the present invention, pressure-sensitive adhesive sheets having further excellent heat resistance can be obtained by appropriately crosslinking a base polymer, particularly an acrylic polymer. As specific means of the crosslinking method, a compound having a group capable of reacting with a carboxyl group, a hydroxyl group, or the like appropriately included as a crosslinking base point in an acrylic polymer such as an isocyanate compound, an epoxy compound, a melamine resin, or an aziridine compound is added. There is a method using a so-called cross-linking agent that is 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.

  In particular, when the pressure-sensitive adhesive composition of the present invention is applied to a surface protective film, an isocyanate compound is particularly preferably used because it is easy to adjust the peeling force appropriately.

  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, examples of the isocyanate compound include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate. -Tolylene diisocyanate, aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), tri Methylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name: Coronate HL), hexamethylene diisocyanate Over the door of the isocyanurate body (Nippon Polyurethane Industry Co., Ltd., trade name: Coronate HX) isocyanate adducts such as, and the like. These isocyanate compounds may be used alone or in combination of two or more.

  Examples of the epoxy compound include N, N, N ′, N′-tetraglycidyl-m-xylenediamine (manufactured by Mitsubishi Gas Chemical Company, trade name: TETRAD-X), and 1,3-bis (N, N-dioxy). Glycidylaminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemical Company, trade name: TETRAD-C). These compounds may be used alone or in combination of two or more.

  Examples of the melamine-based resin include hexamethylol melamine.

  Examples of the aziridine derivative include a commercial product name HDU, a product name TAZM, a product name TAZO (manufactured by Mutual Pharmaceutical Co., Ltd.), and the like. 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 (meth) acrylic polymer to be crosslinked, and further depending on the intended use as the pressure-sensitive 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 part by weight, the crosslinking formation by the crosslinking agent is insufficient, the cohesive force of the pressure-sensitive adhesive composition is reduced, 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. A polyfunctional monomer may be used independently and may be used in mixture of 2 or more types.

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

  The amount of the polyfunctional monomer used is appropriately selected depending on the balance with the (meth) acrylic polymer to be crosslinked, and further depending on the intended use as the pressure-sensitive 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 (meth) acrylic polymer. Moreover, it is more preferable to mix | blend at 10 weight part or less with respect to 100 weight part of (meth) acrylic-type polymers from the point of a softness | flexibility and adhesiveness.

  Examples of the radiation include ultraviolet rays, laser rays, α rays, β rays, γ rays, X rays, electron rays, etc., but ultraviolet rays are preferably used from the viewpoint of good controllability and handleability and cost. It is done. 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-benzoylbenzoic acid methyl-p-benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, benzyldimethyl ketal, trichloro Acetophenones such as acetophenone, 2,2-diethoxyacetophenone and 1-hydroxycyclohexyl phenyl ketone, pros such as 2-hydroxy-2-methylpropiophenone and 2-hydroxy-4′-isopropyl-2-methylpropiophenone Benzophenones such as piophenones, benzophenone, methylbenzophenone, p-chlorobenzophenone, p-dimethylaminobenzophenone, 2-chlorothioxanthone, 2- Thioxanthones such as tilthioxanthone and 2-isopropylthioxanthone, bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, (2,4,6-trimethylbenzoyl) Examples include acylphosphine oxides such as-(ethoxy) -phenylphosphine oxide, benzyl, dibenzosuberone, and α-acyloxime ester.

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

  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. The above photopolymerization initiation assistants may be used alone or in admixture of two or more. 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 (meth) acrylic polymer.

  The pressure-sensitive adhesive composition of the present invention can appropriately contain an alkylene oxide group-containing compound. By containing an alkylene oxide group-containing compound, a pressure-sensitive adhesive composition having further excellent antistatic properties may be obtained.

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

  Examples of the surfactant having an alkylene oxide group include polyoxyalkylene fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene sorbitol fatty acid esters, polyoxyalkylene alkyl ethers, and polyoxyalkylene alkyl allyl ethers. , Nonionic surfactants such as polyoxyalkylene alkyl phenyl ethers, polyoxyalkylene derivatives, polyoxyalkylene alkyl amines, polyoxyalkylene alkyl amine fatty acid esters, polyoxyalkylene alkyl ether sulfate salts, polyoxyalkylene Alkyl ether phosphates, polyoxyalkylene alkyl phenyl ether sulfates, polyoxyalkylene alkyl phenyl ethers Anionic surfactants such as telluric acid salts, cationic surfactants and zwitterionic surfactants having an alkylene oxide group. Moreover, you may have reactive substituents, such as a (meth) acryloyl group and an allyl group, in a molecule | numerator.

  It is more preferable to use a surfactant having an ethylene oxide group in the pressure-sensitive adhesive composition of the present invention. Specific examples include, for example, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene alkylphenyl Nonionic surfactants such as ethers, polyoxyethylene derivatives, polyoxyethylene alkylamines, polyoxyethylene alkylamine fatty acid esters, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl ether phosphates, Anionic surfactants such as polyoxyethylene alkylphenyl ether sulfates and polyoxyethylene alkylphenyl ether phosphates, ethyleneoxy Cationic surfactants and amphoteric surfactants having an group. 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 oxyalkylene unit of the surfactant having an alkylene 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 alkylene 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 oxyalkylene units exceeding 50 is used, the ionic liquid is restrained by the alkylene oxide group and the antistatic property tends to be lowered, which is not preferable.

  The alkylene oxide group-containing compound may be used alone or in combination of two or more, but the blending amount is 0.01 to 10 weights with respect to 100 parts by weight of the base polymer. Part, preferably 0.05 to 5 parts by weight. If it is less than 0.01 part by weight, the effect of balancing the compatibility with the ionic liquid and the base polymer cannot be obtained sufficiently, and if it exceeds 10 parts by weight, bleeding on the adherend increases. It is not preferable because contamination tends to increase.

  Furthermore, the pressure-sensitive adhesive composition used in the pressure-sensitive adhesive sheet of the present invention includes various conventionally known tackifiers, surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, and polymerization inhibition. Add appropriate additives according to the use of various conventionally known additives such as agents, silane coupling agents, inorganic or organic fillers, powders such as metal powders and pigments, particles, foils, etc. Can do.

  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. is there.

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 support substrate, An 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 200 to 4000 mJ / cm ² .

  The method of forming the pressure-sensitive adhesive layer on the film is not particularly limited. For example, the pressure-sensitive adhesive composition is applied to the support film, and the polymerization solvent is dried and 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, extrusion coating using a die coater, 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, silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agents, mold release with silica powder, antifouling 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 with anionic functional groups such as acid salts, sulfate esters, phosphonates, phosphate esters, alkylbetaines and derivatives thereof, imidazolines 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 ion conductive groups of the above cation type, anion type and zwitterionic type 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 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, fluorine, long-chain alkyl or fatty acid amide release agents, mold 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, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene / propylene copolymer Polyolefin films such as ethylene / 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl alcohol copolymer, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, etc. Polyester film, polyacrylate film, polystyrene film, nylon 6, nylon 6,6, polyamide film such as partially aromatic polyamide, polyvinyl chloride film, polyvinylidene chloride film, polycarbonate film Etc., and the like.

  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.

  The pressure-sensitive adhesive composition and the pressure-sensitive adhesive sheet using the present invention are used particularly for plastic products and the like that are likely to generate static electricity, and in particular, polarizing plates, wave plates, optical compensation films, light used for liquid crystal displays and the like. It can be used as a surface protective film used for the purpose of protecting the surface of an optical member such as a diffusion sheet or a reflection sheet.

  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 device (COM-550, manufactured by Hiranuma Sangyo Co., Ltd.) and obtained 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 using a GPC apparatus (HLC-8220 GPC, manufactured by Tosoh Corporation). The measurement conditions are as follows.

Sample concentration: 0.2% by weight (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow rate: 0.6 ml / min
Measurement temperature: 40 ° C
column:
Sample column; TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column; TSKgel SuperH-RC (1)
Detector: Differential refractometer (RI)
The molecular weight was determined in terms of polystyrene.

<Measurement of glass transition temperature>
The glass transition temperature Tg (° C.) of the polymer was determined by the following formula using the following literature values as the glass transition temperature Tgn (° C.) of the homopolymer of each monomer. However, since N-cyclohexylmaleimide has no literature value, it was determined by dynamic viscoelasticity measurement.

Formula: 1 / (Tg + 273) = Σ [Wn / (Tgn + 273)]
[Wherein, Tg (° C.) is the glass transition temperature of the copolymer, Wn (−) is the weight fraction of each monomer, Tgn (° C.) is the glass transition temperature of the homopolymer of each monomer, and n is the type of each monomer Represents. ]
Literature values:
2-ethylhexyl acrylate: -70 ° C
2-hydroxyethyl acrylate: -15 ° C
N, N-diethylacrylamide: 81 ° C
Diacetone acrylamide: 77 ° C
Acryloylmorpholine: 145 ° C

<Dynamic viscoelasticity measurement>
The glass transition temperature (Tg) (° C.) of the polymer containing N-cyclohexylmaleimide was determined by dynamic viscoelasticity measurement according to the following procedure.

  The pressure-sensitive adhesive layer having a thickness of 25 μm was folded to a thickness of about 2 mm, punched out to φ7.9 mm, and a cylindrical pellet was produced to obtain a glass transition temperature (Tg) measurement sample.

Using the above measurement sample, the temperature dependence of the loss elastic modulus G ″ is measured by a dynamic viscoelasticity measuring device (ARES, manufactured by Rheometrics), and the temperature at which the obtained G ″ curve is maximized is measured. The glass transition temperature (Tg) (° C.) was used. The measurement conditions are as follows.
Measurement: Shear mode Temperature range: -70 ° C to 200 ° C
Temperature increase rate: 5 ° C / min
Frequency: 1Hz

<Ionic liquid structure analysis>
The structural analysis of the ionic liquid was performed by NMR measurement, XRF measurement, and FT-IR measurement.

[NMR measurement]
The 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 under the following measurement conditions using a scanning fluorescent X-ray analyzer (manufactured by Rigaku Corporation, ZSX-100e).
Measuring method: filter paper method X-ray source: Rh

[FT-IR measurement]
The FT-IR measurement was performed using an infrared spectrophotometer (manufactured by Nicolet, Magna-560) under the following measurement conditions.
Measuring method: ATR method Detector: DTGS
Resolution: 4.0 cm ⁻¹
Integration count: 64 times

<Preparation of base polymer>
[Production Example 1]
(Acrylic polymer (A))
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel, 190 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of N, N-diethylacrylamide, and 8 parts by weight of 2-hydroxyethyl acrylate Part, 2,2′-azobisisobutyronitrile 0.4 part by weight and 312 parts by weight of ethyl acetate as a polymerization initiator were charged, nitrogen gas was introduced with gentle stirring, and the liquid temperature in the flask was adjusted to 60 ° C. The polymerization reaction was carried out for 5 hours while maintaining the temperature in the vicinity to prepare a solution (40% by weight) of the acrylic polymer (A). This acrylic polymer (A) had Tg = −64 ° C., a weight average molecular weight of 620,000, and an acid value of 0.0.

[Production Example 2]
(Acrylic polymer (B))
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, condenser, and dropping funnel, 190 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of diacetone acrylamide, 8 parts by weight of 2-hydroxyethyl acrylate, polymerization As an initiator, 0.4 part by weight of 2,2′-azobisisobutyronitrile and 312 parts by weight of ethyl acetate were added, and nitrogen gas was introduced while gently stirring to keep the liquid temperature in the flask at around 60 ° C. Then, a polymerization reaction was performed for 5 hours to prepare a solution (40% by weight) of the acrylic polymer (B). This acrylic polymer (B) had Tg = −64 ° C., a weight average molecular weight of 730,000, and an acid value of 0.0.

[Production Example 3]
(Acrylic polymer (C))
In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, cooler, and dropping funnel, 190 parts by weight of 2-ethylhexyl acrylate, 10 parts by weight of acryloylmorpholine, 8 parts by weight of 2-hydroxyethyl acrylate, polymerization start 2,2′-azobisisobutyronitrile 0.43 parts by weight and ethyl acetate 312 parts by weight were introduced as agents, nitrogen gas was introduced with gentle stirring, and the liquid temperature in the flask was kept at around 60 ° C. A polymerization reaction was carried out for 5 hours to prepare a solution (40% by weight) of an acrylic polymer (C). This acrylic polymer (C) had Tg = −63 ° C., a weight average molecular weight of 730,000, and an acid value of 0.0.

[Production Example 4]
(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 N-cyclohexylmaleimide, 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 adjusted to around 60 ° C. The polymerization reaction was carried out for 5 hours to prepare an acrylic polymer (D) solution (40% by weight). This acrylic polymer (D) had Tg = −55 ° C., a weight average molecular weight of 800,000, and an acid value of 0.0.

[Production Example 5]
(Acrylic polymer (E))
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel, 180 parts by weight of 2-ethylhexyl acrylate, 20 parts by weight of N, N-diethylacrylamide, 8 parts by weight of 2-hydroxyethyl acrylate Part, 2,2′-azobisisobutyronitrile 0.4 part by weight and 312 parts by weight of ethyl acetate as a polymerization initiator were charged, nitrogen gas was introduced with gentle stirring, and the liquid temperature in the flask was adjusted to 60 ° C. The polymerization reaction was carried out for 5 hours while maintaining the vicinity, to prepare a solution (40% by weight) of an acrylic polymer (E). This acrylic polymer (E) had Tg = −59 ° C., a weight average molecular weight of 610,000, and an acid value of 0.0.

[Production Example 6]
(Acrylic polymer (F))
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 5 hours while maintaining the liquid temperature in the flask at around 60 ° C. A solution (40% by weight) of an acrylic polymer (F) was prepared. This acrylic polymer (F) had Tg = −68 ° C., a weight average molecular weight of 550,000, and an acid value of 0.0.

<Preparation of ionic liquid (1)>
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 is added to 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 under an environment of 110 ° C. for 2 hours to obtain 20 parts by weight of an ionic liquid (1) that was liquid at 25 ° C. It was. The obtained ionic liquid (1) was subjected to NMR ( ¹ H, ¹³ C) measurement, FT-IR measurement, and XRF measurement, and identified as 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide. ·confirmed.

<Preparation of antistatic agent>
[Antistatic agent solution (a)]
A four-necked flask equipped with a stirring blade, a thermometer, and a cooler is charged with 10 parts by weight of the ionic liquid (1) and 90 parts by weight of ethyl acetate, and the liquid temperature in the flask is kept near room temperature (25 ° C.). Then, the mixture was stirred for 30 minutes to prepare an antistatic agent solution (a) (10% by weight).

[Antistatic agent solution (b)]
In a four-necked flask equipped with a stirring blade, a thermometer, and a condenser, 5 parts by weight of the ionic liquid (1), a nonionic reactive surfactant (Adeka Soap ER-10, manufactured by Asahi Denka Kogyo Co., Ltd.) 5 parts by weight and 90 parts by weight of ethyl acetate were charged, and the mixture was stirred for 30 minutes while maintaining the liquid temperature in the flask at around room temperature (25 ° C.) to prepare an antistatic agent solution (b) (10% by weight).

[Antistatic agent solution (c)]
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., Inc., 25 10 parts by weight of liquid at 90 ° C. and 90 parts by weight of ethyl acetate, and the mixture was stirred for 30 minutes while maintaining the liquid temperature in the flask at about room temperature (25 ° C.) to obtain an antistatic agent solution (c) (10% by weight). ) Was prepared.

[Antistatic agent solution (d)]
In a four-necked flask equipped with a stirring blade, a thermometer, and a condenser, 9.8 parts by weight of the ionic liquid (1), 3 weights of a nonionic reactive surfactant (Ramtel PD-420, manufactured by Kao Corporation) Parts and ethyl acetate 115.2 parts by weight, and the mixture was stirred for 30 minutes while maintaining the liquid temperature in the flask at around room temperature (25 ° C.) to prepare an antistatic agent solution (d) (10% by weight). .

[Antistatic agent solution (e)]
In a four-necked flask equipped with a stirring blade, a thermometer, and a cooler, 5 parts by weight of an aliphatic amine-based ionic liquid (manufactured by Guangei Chemical Industry Co., Ltd., IL-A5, liquid at 25 ° C.), nonionic reactivity 5 parts by weight of a surfactant (Asahi Denka Kogyo Co., Ltd., Adeka Soap ER-10) and 90 parts by weight of ethyl acetate were added, and the mixture was stirred for 30 minutes while keeping the liquid temperature in the vicinity of room temperature (25 ° C.). An antistatic agent solution (e) (10% by weight) was prepared.

[Antistatic agent solution (f)]
In a four-necked flask equipped with a stirring blade, a thermometer, and a condenser, an alicyclic amine-based ionic liquid (manufactured by Guangei Chemical Industry Co., Ltd., IL-C1, liquid at 25 ° C.) 4 parts by weight, nonionic reaction Antistatic agent (Kao Co., Ltd., Ramter PD-420) 6 parts by weight and ethyl acetate 90 parts by weight, keeping the liquid temperature in the flask near room temperature (25 ° C) and mixing and stirring for 30 minutes An agent solution (f) (10% by weight) was prepared.

[Antistatic agent solution (g)]
A four-necked flask equipped with a stirring blade, thermometer, and condenser is charged with 0.1 parts by weight of lithium iodide, 9.9 parts by weight of polypropylene glycol (number average molecular weight 2000, diol type), and 90 parts by weight of ethyl acetate. The mixture was stirred for 2 hours while maintaining the liquid temperature in the flask at around 80 ° C. to prepare an antistatic agent solution (g) (10% 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) is diluted to 20% by weight with ethyl acetate, and 100 parts by weight of this solution is added with 3 parts by weight of an antistatic agent solution (a) (10% by weight) as a crosslinking agent. Add 0.6 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. The mixture was stirred for about 1 minute to prepare an acrylic pressure-sensitive adhesive solution (1).

(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 (B) solution (40% by weight) is diluted with ethyl acetate to 20% by weight, and 100 parts by weight of this solution is mixed with 6 parts by weight of the antistatic agent solution (b) (10% by weight) and a crosslinking agent. As an isocyanurate form 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, The acrylic pressure-sensitive adhesive solution (2) 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 (2) was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 3
(Preparation of adhesive composition)
The acrylic polymer (C) solution (40% by weight) is diluted with ethyl acetate to 20% by weight, and 100 parts by weight of this solution is mixed with 6 parts by weight of the antistatic agent solution (b) (10% by weight) and a crosslinking agent. As an isocyanurate form 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, The acrylic pressure-sensitive adhesive solution (3) 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 (3) was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 4
(Preparation of adhesive composition)
A solution (40% by weight) of the acrylic polymer (D) is diluted to 20% by weight with ethyl acetate, and 6 parts by weight of the antistatic agent solution (b) (10% by weight) is added to 100 parts by weight of this solution. As an isocyanurate form 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, The acrylic pressure-sensitive adhesive solution (4) 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 (4) was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 5
(Preparation of adhesive composition)
A solution (40% by weight) of the acrylic polymer (E) is diluted to 20% by weight with ethyl acetate, and 6 parts by weight of the antistatic agent solution (a) (10% by weight) is added to 100 parts by weight of this solution. As an isocyanurate form 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, The acrylic pressure-sensitive adhesive solution (5) was prepared by mixing and stirring for about 1 minute.

(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)
A solution (40% by weight) of the acrylic polymer (E) is diluted to 20% by weight with ethyl acetate, 2 parts by weight of the antistatic agent solution (c) (10% by weight) is added to 100 parts by weight of this solution, and a crosslinking agent. As an isocyanurate form 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, The acrylic pressure-sensitive adhesive solution (6) 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 (6) was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 7
(Preparation of adhesive composition)
The acrylic polymer (A) solution (40% by weight) is diluted to 20% by weight with ethyl acetate, and 12.8 parts by weight of the antistatic agent solution (d) (10% by weight) is added to 100 parts by weight of this solution. Add 0.6 part by weight of isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) as a crosslinking agent, and add 0.4 part by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst. An acrylic pressure-sensitive adhesive solution (7) was prepared by mixing and stirring for about 1 minute at (25 ° C.).

(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).

Example 8
(Preparation of adhesive composition)
The acrylic polymer (C) solution (40% by weight) is diluted to 20% by weight with ethyl acetate, and 100 parts by weight of this solution is mixed with 6 parts by weight of the antistatic agent solution (e) (10% by weight) and a crosslinking agent. As an isocyanurate form 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, The acrylic pressure-sensitive adhesive solution (8) 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 (8) was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 9
(Preparation of adhesive composition)
A solution (40% by weight) of the acrylic polymer (A) is diluted to 20% by weight with ethyl acetate, 5 parts by weight of the antistatic agent solution (f) (10% by weight) is added to 100 parts by weight of this solution, and a crosslinking agent. As an isocyanurate form 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, The acrylic pressure-sensitive adhesive solution (9) 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 (9) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 1]
(Preparation of adhesive composition)
A solution (40% by weight) of the acrylic polymer (F) is diluted to 20% by weight with ethyl acetate, and 2 parts by weight of the antistatic agent solution (a) (10% by weight) is added to 100 parts by weight of this solution. As an isocyanurate form 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, The acrylic pressure-sensitive adhesive solution (10) 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 (10) 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 (F) is diluted to 20% by weight with ethyl acetate, and 14 parts by weight of the antistatic agent solution (g) (10% by weight) is added to 100 parts by weight of this solution. As an isocyanurate form 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, The acrylic pressure-sensitive adhesive solution (11) 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 (11) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 3]
(Preparation of adhesive composition)
A solution (40% by weight) of the acrylic polymer (F) was diluted to 20% by weight with ethyl acetate, and dialkylsulfosuccinate sodium salt (Daiichi Kogyo Seiyaku Co., Ltd.) as an anionic surfactant was added to 100 parts by weight of this solution. Manufactured by Neocor P) 2.0 parts by weight, trimethylolpropane / tolylene diisocyanate trimer adduct (Nihon Polyurethane Industry Co., Ltd., Coronate L, 75 wt% ethyl acetate solution) as a crosslinking agent, 1 part by weight as a crosslinking catalyst An acrylic pressure-sensitive adhesive solution (12) was prepared by adding 0.6 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) 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 (12) was used instead of the acrylic pressure-sensitive adhesive solution (1).

  About the adhesive sheet obtained by said Example and comparative example, peeling voltage, pollution property, adhesive force, and generation | occurrence | production of a float were evaluated in the following way.

<Measurement of peeling voltage>
The pressure-sensitive adhesive sheet was cut to a size of 70 mm in width and 130 mm in length, the separator was peeled off, and then the acrylic plate (Mitsubishi Rayon Co., Acrylite, thickness: 1 mm, width: 70 mm, length: 100 mm, which had been previously neutralized. ) Was bonded to the surface of the polarizing plate (manufactured by Nitto Denko Corporation, SEG1425WVAGS2B, width: 70 mm, length: 100 mm) with 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 machine (KSD-0103, manufactured by Kasuga Denki Co., Ltd.) fixed at the center position in the sample length direction. The measurement was performed in an environment of 23 ° C. × 50% RH.

<Evaluation of contamination>
After the adhesive sheet is cut into a size of 50 mm in width and 80 mm in length and the separator is peeled off, it is pressure-bonded to a polarizing plate (manufactured by Nitto Denko Corporation, SEG1425DU, width: 70 mm, length: 100 mm) with a hand roller, and an evaluation sample Was made.

The evaluation sample was allowed to stand in an environment of 50 ° C. × 92% RH for 24 hours and then in an environment of 23 ° C. × 50% RH for 2 hours, and then the pressure-sensitive adhesive sheet was peeled off from the adherend by hand. The contamination state of the surface of the adherend was visually observed. The evaluation criteria are as follows.
If no contamination was found: ○
If contamination is found: ×

<Adhesion measurement>
After the adhesive sheet was cut to a size of 25 mm in width and 100 mm in length and the separator was peeled off, it was laminated to a polarizing plate (manufactured by Nitto Denko Corporation, SEG1425DU, width: 70 mm, length: 100 mm) at a pressure of 0.25 MPa, An evaluation sample was prepared.

  After lamination, the laminate was allowed to stand for 30 minutes in an environment of 23 ° C. × 50% RH, 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.

<Evaluation of occurrence of floating>
After the adhesive sheet was cut into a size of 40 mm in width and 40 mm in length and the separator was peeled off, it was laminated to a polarizing plate (manufactured by Nitto Denko Corporation, SEG1425WVAGS2B, width: 70 mm, length: 100 mm) at a pressure of 0.25 MPa, An evaluation sample was prepared.

After lamination, the above evaluation sample is fixed to a slide glass (manufactured by Matsunami Glass Industrial Co., Ltd., water edge polish, thickness: 1.3 mm, width: 65 mm, length: 165 mm), and autoclaved for 20 minutes in an environment of 50 ° C. × 5 atm. Processed. Then, after standing for 2 hours in an environment of 80 ° C. and normal pressure, it was visually confirmed whether or not the pressure-sensitive adhesive sheet floated from the polarizing plate. The evaluation criteria are as follows.
If no floating is observed: ○
When floating is observed: ×

  The results are shown in Table 1.

  According to the results in Table 1 above, when the pressure-sensitive adhesive composition prepared according to the present invention was used (Examples 1 to 9), the stripping voltage to the polarizing plate was suppressed in all the examples, and the polarizing plate was obtained. It was clarified that there was no occurrence of contamination, no further floating, and excellent adhesion reliability.

  On the other hand, in the case of using the pressure-sensitive adhesive composition not containing the nitrogen-containing monomer as a monomer unit (Comparative Examples 1 to 3), the stripping voltage was suppressed in any case, but the contamination As a result, the occurrence of floating was observed. Therefore, in all of the comparative examples, in addition to adhesion reliability, it was impossible to achieve both suppression of the peeling voltage to the polarizing plate as the adherend and suppression of occurrence of contamination and floating.

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

Claims (6)

Nitrogen-containing monomer having 0.5 to 30 wt% as a monomer unit, and Ri Na contain polymer glass transition temperature Tg of 0 ℃ or less, and the ionic liquid,
The polymer is a (meth) acrylic polymer having as a main component one or more of acrylate and / or methacrylate having an alkyl group having 1 to 14 carbon atoms,
It said nitrogen-containing monomer is an amide group-containing monomers, amino group-containing monomers, imide group-containing monomers, cyano group-containing monomer, and the adhesive agent characterized at least Tanedea Rukoto selected from the group consisting of acryloyl morpholine Composition.   The pressure-sensitive adhesive composition according to claim 1, wherein the ionic liquid is one or more 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 _C 16. Represents a hydrocarbon group and may contain heteroatoms. 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 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 heteroatoms. However, when Z is a sulfur atom, there is no _Ro . ] The adhesive layer formed by bridge | crosslinking the adhesive composition in any one of Claims 1-3 . Pressure-sensitive adhesive sheet, wherein by crosslinking the pressure-sensitive adhesive layer a pressure-sensitive adhesive composition, that obtained by forming on one or both sides of the support according to any one of claims 1-3. A pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition according to any one of claims 1 to 3 is formed on one side or both sides on a support made of a plastic substrate subjected to antistatic treatment. Characteristic surface protective film.