JP2006348273A - Adhesive composition, adhesive sheet, and surface protection film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adhesive composition which is antistatic upon stripping of an adherend having not been subjected to antistatic finish from an adhesive layer and achieves a lower level of contamination to the adherend, an antistatic adhesive sheet using the adhesive composition, and a surface protection film using the adhesive composition. <P>SOLUTION: The adhesive composition comprises a (meth)acrylic polymer dispersible in water that contains, as a monomer component, 50 to 99.9% by weight of (meth)acrylate having an alkyl group with a carbon number between 1 and 14 and an ionic liquid. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an antistatic pressure-sensitive adhesive composition, and an antistatic pressure-sensitive adhesive sheet and a surface protective film which are formed into a sheet form or a tape form using the same.

  The pressure-sensitive adhesive sheet made of the antistatic pressure-sensitive adhesive composition of the present invention is suitably used for plastic products and the like that easily 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 equipment.

  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 wave plate to a liquid crystal cell via an adhesive. For 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 even when the protective film is peeled off from the protected body, resulting in deterioration of workability and damage to the protected body. 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.

  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.

  On the other hand, in recent years, pressure-sensitive adhesives that do not use organic solvents are required from the viewpoints of environmental measures, resource saving, safety, and the like.

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

  In light of such circumstances, the present invention provides an adhesive composition capable of preventing charge at the time of peeling of the pressure-sensitive adhesive layer and the non-antistatic adherend, and reducing contamination on the adherend. An object is to provide an antistatic pressure-sensitive adhesive sheet and a surface protective film used.

  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 is a water-dispersed (meth) acrylic polymer containing 50 to 99.9% by weight of (meth) acrylate having a C 1-14 alkyl group as a monomer component, And an ionic liquid.

  In addition, the ionic liquid in this invention refers to the molten salt (ionic compound) which exhibits a liquid state at room temperature (25 degreeC).

  According to the pressure-sensitive adhesive composition of the present invention, as shown in the results of Examples, water dispersion containing 50 to 99.9% by weight of (meth) acrylate having a C 1-14 alkyl group as a monomer component Since a type (meth) acrylic polymer is used as a base polymer and further contains an ionic liquid, the pressure-sensitive adhesive layer cross-linked with this reduces the contamination to the object to be protected (adhered body). The adhesive layer and the non-antistatic adherend are excellent in antistatic properties. Although the details of the reason why such a water-dispersed (meth) acrylic polymer and a cross-linked product of an ionic liquid exhibit such characteristics are not clear, a small amount is sufficient because the ionic liquid exhibits excellent conductivity by itself. Antistatic ability is obtained, and it is estimated that contamination is reduced.

  In addition, since the above ionic liquid is liquid 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.

  The pressure-sensitive adhesive composition of the present invention is based on a water-dispersed (meth) acrylic polymer containing 50 to 99.9% by weight of (meth) acrylate having a C 1-14 alkyl group as a monomer component. Used as a polymer.

  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.

  Further, the water-dispersed (meth) acrylic polymer in the present invention emulsifies a monomer blend having 50 to 99.9% by weight of (meth) acrylate having 1 to 14 carbon atoms as a monomer component. A (meth) acrylic polymer in an aqueous dispersion (dispersion) obtained by polymerization. By using these (meth) acrylic polymers as the base polymer, the balance of the compatibility between the ionic liquid and the base polymer is improved, the adhesive properties can be sufficiently maintained, and the water-dispersed pressure-sensitive adhesive A composition can be obtained.

  In addition, since an organic solvent is not used, there is an advantage that the dry polymer film does not swell or dissolve even if it is applied on a normal dry polymer film. It is also possible to meet the demand for preferably using an adhesive composition that is not used.

  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 ionic liquid is preferably a water-soluble ionic liquid. By using a water-soluble ionic liquid, better compatibility with the water-dispersed (meth) acrylic polymer can be realized.

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

  The pressure-sensitive adhesive sheet of the present invention is characterized in that a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition described above is formed on a support. According to the pressure-sensitive adhesive sheet of the present invention, since the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition having the above-described effects is provided, when peeled, the pressure-sensitive adhesive layer and the non-antistatic adherend are applied. The pressure-sensitive adhesive sheet can be prevented from being charged and the contamination of the adherend is reduced. In addition, the adhesive sheet in this invention contains an adhesive tape, an adhesive film, etc.

  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.

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

  The pressure-sensitive adhesive composition of the present invention includes a water-dispersed (meth) acrylic polymer containing 50 to 99.9% by weight of a (meth) acrylate having a C 1-14 alkyl group as a monomer component, and ions It is characterized by containing an ionic liquid.

  In addition, the ionic liquid in this invention refers to the molten salt (ionic compound) which exhibits a liquid state at room temperature (25 degreeC).

  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-methyl-1-ethylpyrrolidinium cation, 1-methyl-1-propylpyrrolidi Cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium cation 1-ethyl-1-propylpyrrolidini Cation, 1-ethyl-1-butylpyrrolidinium cation, 1-ethyl-1-pentylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation, 1-ethyl-1-heptylpyrrolidinium cation, 1,1-dipropylpyrrolidinium cation, 1-propyl-1-butylpyrrolidinium cation, 1,1-dibutylpyrrolidinium cation, 1-propylpiperidinium cation, 1-pentylpiperidinium cation, 1 , 1-dimethylpiperidinium cation, 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-butylpiperidinium cation, 1-methyl-1 -Pentylpiperidinium cation, 1-methyl-1-hexylpiperidi Cation, 1-methyl-1-heptylpiperidinium cation, 1-ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl-1-heptylpiperidinium cation, 1,1-dipropylpiperidinium cation, 1-propyl-1-butylpiperidinium cation, 1-butyl -1-pentylpiperidinium cation, 1-butyl-1-hexylpiperidinium cation, 1-butyl-1-heptylpiperidinium cation, 1,1-dibutylpiperidinium cation, 2-methyl-1-pyrroline Cation, 1-ethyl-2-phenylindole cation, 1,2-dimethyl Examples thereof include a ruindole 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 1-hexadecyl-3-methylimidazolium cation, 1-octadecyl-3-methylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation 1-butyl-2, -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-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3- Trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetra Chill-1,4-dihydropyrimidinium cation, such as 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation.

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

  Specific examples include, for example, 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2,3,5-trimethylpyrazolium cation, 1-pile pill-2,3,5. -Trimethyl pyrazolium cation, 1-butyl-2,3,5-trimethyl pyrazolium 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, triethylmethylammonium cation, tributylethylammonium Cation, trimethyldecyl ammonium cation, trioctyl methyl ammonium cation, tripentyl butyl ammonium cation, trihexyl methyl ammonium cation, trihexyl pentyl ammonium cation, triheptyl methyl ammonium cation, triheptyl hexyl ammonium cation, N, N-diethyl-N -Methyl-N- ( -Methoxyethyl) ammonium cation, glycidyl trimethyl ammonium cation, diallyl dimethyl ammonium cation, N, N-dimethyl-N, N-dipropyl ammonium cation, N, N-dimethyl-N, N-dihexyl ammonium 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-ethyl-N-heptylammonium cation, N, N-dimethyl-N-ethyl- N-nonylammoniu 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-pentyl-N-hexylammonium cation, N, N-dimethyl-N-hexyl-N-heptylammonium cation, trimethylheptylammonium cation, N, N-diethyl-N-methyl-N-propylammonium cation N, N-diethyl-N-methyl- N-pentylammonium cation, N, N-diethyl-N-methyl-N-heptylammonium cation, N, N-diethyl-N-propyl-N-pentylammonium cation, triethylmethylammonium cation, triethylpropylammonium cation, triethylpentyl Ammonium cation, triethylheptylammonium cation, N, N-dipropyl-N-methyl-N-ethylammonium cation, N, N-dipropyl-N-methyl-N-pentylammonium cation, N, N-dipropyl-N-butyl- N-hexyl ammonium cation, N, N-dibutyl-N-methyl-N-pentyl ammonium cation, N, N-dibutyl-N-methyl-N-hexyl ammonium cation, trioctyl methyl cation Monium cation, N-methyl-N-ethyl-N-propyl-N-pentylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecyl Sulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrapentylphosphonium cation, tetrahexylphosphonium cation, tetraheptylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecyl Such as phosphonium cation and the like.

  Among them, triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, trioctylmethylammonium cation, tripentylbutylammonium cation, trihexylmethylammonium cation, trihexylpentylammonium cation, triheptylmethylammonium cation, triheptyl Hexylammonium cation, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, N, N-dimethyl-N-ethyl-N-propylammonium cation, N, N- Dimethyl-N-ethyl-N-butylammonium cation, N, N-dimethyl-N-ethyl-N-pentylammonium Cation, N, N-dimethyl-N-ethyl-N-hexylammonium cation, N, N-dimethyl-N-ethyl-N-heptylammonium cation, N, N-dimethyl-N-ethyl-N-nonylammonium cation, N, N-dimethyl-N-propyl-N-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-pentyl-N-hexylammonium cation, N, N- Methyl-N-hexyl-N-heptylammonium cation, N, N-dimethyl-N, N-dihexylammonium cation, trimethylheptylammonium cation, N, N-diethyl-N-methyl-N-propylammonium cation, N, N -Diethyl-N-methyl-N-pentylammonium cation, N, N-diethyl-N-methyl-N-heptylammonium cation, N, N-diethyl-N-propyl-N-pentylammonium cation, triethylpropylammonium cation, Triethylpentylammonium cation, triethylheptylammonium cation, N, N-dipropyl-N-methyl-N-ethylammonium cation, N, N-dipropyl-N-methyl-N-pentylammonium cation, N, N-dipropyl-N-butyl-N-hexylammonium cation, N, N-dipropyl-N, N-dihexylammonium cation, N, N-dibutyl-N-methyl-N-pentylammonium cation, N, N-dibutyl- Tetraalkylammonium cations such as N-methyl-N-hexylammonium cation, trioctylmethylammonium cation, N-methyl-N-ethyl-N-propyl-N-pentylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium Trialkylsulfonium cation such as cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation Cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrapentylphosphonium cation, tetrahexylphosphonium cation, tetraheptylphosphonium cation, tetraoctylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecylphosphonium cation Tetraalkylphosphonium cations such as 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. Specifically, 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 ^- it 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 a combination of the above cation component and anion component.

  Specific examples include, for example, 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium hexafluorophosphate, 1-butyl-3-methylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl -3-methylpyridinium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylpyridinium bis (pentafluoroethanesulfonyl) imide, 1-hexylpyridinium tetrafluoroborate, 2-methyl-1-pyrroline tetrafluoroborate, 1-ethyl-2-phenylindole tetrafluoroborate, 1,2-dimethylindole tetrafluoroborate, 1-ethylcarbazole tetrafluoroborate, 1-ethyl- -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 dicyanamide, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide 1-ethyl-3-methylimidazolium bis (pentafluoroethanesulfonyl) imide, 1-ethyl-3-methylimidazolium tris (trifluoromethanesulfonyl) methide, 1-butyl-3-methyl Louis imidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium trifluoroacetate, 1-butyl-3-methylimidazolium heptafluorobutyrate, 1-butyl -3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium perfluorobutanesulfonate, 1-butyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-hexyl-3-methylimidazolium Bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium tetrafluoroborate, 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-2,3-dimethyl Imidazolium tetrafluoroborate, 1,2-dimethyl-3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-methylpyrazolium tetrafluoroborate, 3-methylpyrazolium tetrafluoroborate, tetrahexylammonium bis ( Trifluoromethanesulfonyl) imide, diallyldimethylammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis (tri Fluoromethanesulfonyl) imide, diallyldimethylammonium bis (pentafluoroethanesulfonyl) imide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium tetrafluoroborate, N, N-diethyl-N-methyl -N- (2-methoxyethyl) ammonium trifluoromethanesulfonate, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl -N- (2-methoxyethyl) ammonium bis (pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium trifluoromethanesulfonate, glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, Lysidyltrimethylammonium bis (pentafluoroethanesulfonyl) imide, 1-butylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-3-methyl Imidazolium (trifluoromethanesulfonyl) trifluoroacetamide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium (trifluoromethanesulfonyl) trifluoroacetamide, diallyldimethylammonium (trifluoromethanesulfonyl) trifluoroacetamide Glycidyltrimethylammonium (trifluoromethanesulfonyl) trifluoroacetamide, N, N-dimethyl-N- Ethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-pentylammonium Bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-heptylammonium bis (trifluoromethane Sulfonyl) imide, N, N-dimethyl-N-ethyl-N-nonylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N, N-dipropylammonium bis (trifluoromethanesulfonyl) imide, N, N -Jimee Ru-N-propyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl- N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-hexyl Ammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-pentyl-N-hexylammonium bis (trifluoro) Lomethanesulfur Nyl) imide, N, N-dimethyl-N, N-dihexylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-propylammonium bis (Trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-heptylammonium bis (trifluoromethanesulfonyl) Imido, N, N-diethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, triethylpropylammonium bis (trifluoromethanesulfonyl) imide, triethylpentyl Ammonium bis (trifluoromethanesulfonyl) imide, triethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dipropyl-N-methyl-N-ethylammonium bis (trifluoromethanesulfonyl) 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-hexylan Niumubisu (trifluoromethanesulfonyl) imide, trioctyl methyl ammonium bis (trifluoromethanesulfonyl) imide, etc. N- methyl -N- ethyl -N- propyl -N- pentyl ammonium bis (trifluoromethanesulfonyl) imide and the like.

  The ionic liquid used in the present invention is appropriately selected from the combination of the cation component and the anion component, and is preferably water-soluble.

  Specific examples of the water-soluble ionic liquid include, for example, 1-ethyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium trifluoro. L-methanesulfonate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium Chloride, 1-octyl-3-methylimidazolium chloride, 1-decyl-3-methylimidazolium chloride, 1-dodecyl-3-methylimidazolium chloride, 1-tetradecyl-3-methylimidazolium chloride, 1-to Sadecyl-3-methylimidazolium chloride, 1-hexyl-2,3-dimethylimidazolium bromide, 1-hexyl-2,3-dimethylimidazolium chloride, 1-butylpyridinium trifluoromethanesulfonate, 1-hexylpyridinium bromide 1-hexylpyridinium chloride, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, and the like.

  A commercially available ionic liquid as described above may be used, but it can also be synthesized as follows.

  The method of synthesizing the ionic liquid is not particularly limited as long as the target ionic liquid can be obtained. In general, however, it is described in the document “Ionic liquids: the forefront and future of development” (issued by CMC Publishing). As described, a halide method, a hydroxide method, an acid ester method, a complex formation method, a neutralization method, and the like 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).

The obtained halide is an acid (HA) or salt having the anion structure (A ⁻ ) of the target ionic liquid (MA and M form a salt with the target anion such as ammonium, lithium, sodium, potassium, etc.) The target ionic liquid (R ₄ NA) is obtained by reacting with a cation).

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 Esters and esters of organic acids such as methanesulfonic acid, methylphosphonic acid and formic acid are used).

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

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 salt 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 described in the above (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. Part is preferable, 0.03 to 20 parts by weight is more preferable, and 0.05 to 10 parts by weight is most preferable. If it is less than 0.01 part by weight, sufficient antistatic properties cannot be obtained, and if it exceeds 40 parts by weight, the contamination of the adherend tends to increase.

  In the present invention, a water-dispersed (meth) acrylic polymer containing 50 to 99.9% by weight of a (meth) acrylate having an alkyl group having 1 to 14 carbon atoms as a monomer component is used as a base polymer. By using these (meth) acrylic polymers as the base polymer, the compatibility balance between the ionic liquid and the base polymer is improved, and the adhesive properties can be sufficiently maintained.

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

  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.

  Among these, when used for the surface protective film of the present 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 and the like are preferably used. By using a (meth) acrylic polymer composed of (meth) acrylates mainly composed of these alkyl groups having 6 to 14 carbon atoms, it becomes easy to control the adhesive force to the adherend to be low, and re-peeling Excellent in properties.

  The (meth) acrylate having an alkyl group having 1 to 14 carbon atoms described above may be used alone or in combination of two or more, but the total amount of (meth) acrylic polymer It is preferable that it is 50-99.9 weight% in a body component, 60-99.5 weight% is more preferable, 70-99 weight% is further more preferable. By using the (meth) acrylic polymer whose main component is a (meth) acrylate having an alkyl group having 1 to 14 carbon atoms as described above, the compatibility balance between the ionic liquid and the base polymer is improved, and adhesion is achieved. The characteristics can be sufficiently maintained.

  In the present invention, in addition to the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms, a functional group-containing monomer capable of reacting with a crosslinking agent, a glass transition point of a (meth) acrylic polymer, Other polymerizable monomer components for adjusting the peelability can be used.

  However, when (meth) acrylate having an acid functional group such as a carboxyl group or a sulfonic acid group is used, it is preferable to adjust the acid value of the (meth) acrylic polymer to 40 or less. When the acid value of the (meth) acrylic polymer exceeds 40, the antistatic property tends to deteriorate. Preferably it is 29 or less.

  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 is mentioned. In this case, the acid value is adjusted to 40 or less by adjusting acrylic acid to 5.1 parts by weight or less with respect to 100 parts by weight of the total amount of 2-ethylhexyl acrylate and acrylic acid. The value can be Moreover, the said acid value can be made into the value of 29 or less by adjusting acrylic acid to 3.7 weight part or less.

  Examples of the functional group-containing monomer include cross-linking such as a carboxyl group-containing monomer, an acid anhydride group-containing monomer, a hydroxyl group-containing monomer, an amino group-containing monomer, an epoxy group-containing monomer, an isocyanate group-containing monomer, and an aziridine group-containing monomer. A component having a functional group serving as a base point can be appropriately used.

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

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

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl ( (Meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethylcyclohexyl) methyl acrylate, N-methylol (meth) acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl Examples thereof include vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and the like.

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

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

  Examples of the isocyanate group-containing monomer include 2-methacryloyloxyethyl isocyanate.

  The above-mentioned functional group-containing (meth) acrylate may be used alone or in combination of two or more, but the total content is the total monomer of the (meth) acrylic polymer The content is preferably 0.1 to 15% by weight, more preferably 0.2 to 12% by weight, and particularly preferably 0.3 to 10% by weight. If the content of the functional group-containing (meth) acrylate is less than 0.1% by weight, the cross-linking by the cross-linking agent becomes insufficient, the cohesive force of the pressure-sensitive adhesive composition becomes small, and the adhesive remains. Tend. On the other hand, when the content of the functional group-containing (meth) acrylate exceeds 15% by weight, the cohesive force of the pressure-sensitive adhesive composition becomes too large, the fluidity is lowered, and the adherend is not sufficiently wetted. , Tend to cause peeling.

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

  Other polymerizable monomer components include, for example, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, vinyl esters, aromatic vinyl compounds and other cohesive force / heat resistance improving components, amides, etc. A component having a functional group functioning as an adhesive strength improvement or crosslinking base point such as a group-containing monomer, an imide group-containing monomer, N- (meth) acryloylmorpholine, and vinyl ether can be used as appropriate.

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

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

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

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

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

  Examples of amide group-containing monomers include acrylamide, methacrylamide, diethyl acrylamide, N-vinyl pyrrolidone, N, N-dimethyl acrylamide, N, N-dimethyl methacrylamide, N, N-diethyl acrylamide, N, N-diethyl methacryl. Examples include amide, N, N′-methylenebisacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, and diacetone acrylamide.

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

  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 combination of two or more, but the total content is the total amount of the (meth) acrylic polymer. It is preferable that it is 0-35 weight% in a body component, 0-30 weight% is more preferable, and 0-25 weight% is especially preferable. By using the other polymerizable monomer components described above, good interaction with the ionic liquid and good adhesiveness can be appropriately adjusted.

  Moreover, it is preferable that the glass transition temperature (Tg) of the said (meth) acrylic-type polymer is normally -100 degreeC-0 degreeC as a base polymer, and it is more preferable that it is -80 degreeC--10 degreeC. 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 (meth) acrylic-type polymer can be adjusted in the said range by changing suitably the monomer component to be used and those composition ratios.

  As the (meth) acrylic polymer of the present invention, a water-dispersed (meth) acrylic polymer obtained by emulsion polymerization of the above-described monomer component (monomer) blend in the presence of an emulsifier is used. Used. Moreover, the polymer obtained may be any of a random copolymer, a block copolymer, a graft copolymer, and the like.

  In the present invention, the emulsifier, the polymerization initiator and the like used for the emulsion polymerization are not particularly limited and can be appropriately selected and used.

  Examples of the emulsifier used in the present invention include anionic emulsifiers such as alkyl sulfates, alkylbenzene sulfonates, alkyl sulfosuccinates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl phosphates, and polyoxyethylene. Nonionic emulsifiers such as alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene-polyoxypropylene block polymers, sorbitan fatty acid esters, and polyoxyethylene fatty acid esters can be exemplified.

  Furthermore, as the emulsifier, a reactive emulsifier into which a radical polymerizable functional group (reactive functional group) such as a propenyl group, an allyl group, a (meth) acryloyl group, or an allyl ether group is introduced may be used. Since it has a radical polymerizable functional group, it is incorporated into the base polymer chain by reaction, so that bleeding of the emulsifier to the adherend can be prevented.

  Further, a reactive emulsifier having an alkylene oxide group may be used as the reactive emulsifier. By using a reactive emulsifier having an alkylene oxide group, the reaction causes the alkylene oxide group to be incorporated into the base polymer chain, thereby improving the compatibility between the base polymer and the ionic liquid, and ionicity to the adherend. Liquid bleeding is suitably suppressed, and a low-staining adhesive composition is obtained.

  Examples of the reactive emulsifier having an alkylene oxide group include, for example, Aqua Open HS-10, HS-20, KH-10, BC-05, BC-10, BC-20, and BC-2020 (all of which are Ichi Kogyo Seiyaku Co., Ltd.), Adekaria Soap SE-10N (Asahi Denka Kogyo Co., Ltd.), Latemul PD-104 (Kao Corporation), and the like.

  The above emulsifiers may be used singly or in combination of two or more, but the total content is 100 parts by weight of monomer due to polymerization stability and mechanical stability. The amount is preferably 0.1 to 10 parts by weight, and more preferably 0.3 to 5 parts by weight.

  As an example of the polymerization operation, for example, the above-mentioned monomers and copolymerization monomers are first mixed, and after emulsifying and water are added thereto, the mixture is emulsified to prepare an emulsion. The monomer at this time may be blended in whole or in part with the total amount used, and the remainder may be dropped during the polymerization. Next, a polymerization initiator and, if necessary, water are added to this emulsion to carry out emulsion polymerization (emulsion polymerization).

  In addition, water may be blended only at the time of preparing the emulsion, or may be further blended thereafter, and can be appropriately selected according to the polymerization method described later. The amount of water is not particularly limited, but the solid content concentration of the (meth) acrylic polymer after emulsion polymerization (emulsion polymerization) is 30 to 75% by weight, preferably 35 to 70% by weight. Prepare to be.

  The method of emulsion polymerization (emulsion polymerization) is not particularly limited, and may be appropriately selected from a batch polymerization method (collective charging method), a continuous dropping method (monomer dropping method, monomer emulsion dropping method), a polymerization method combining these, and the like. Can do.

  In the batch polymerization method, for example, a monomer mixture, an emulsifier, and water are charged into a reaction vessel and emulsified by stirring and mixing to prepare an emulsion. Then, a polymerization initiator and water as necessary are added to the reaction vessel to perform emulsion polymerization ( Emulsion polymerization).

  In the continuous dropping method, for example, a monomer mixture, an emulsifier and water are first added and emulsified by stirring and mixing to prepare a dropping solution, and a polymerization initiator and water are charged into the reaction vessel, and then the dropping solution is added to the reaction vessel. It is dripped in and emulsion polymerization (emulsion polymerization) is carried out.

  As additives after emulsion polymerization, for example, known ones such as pH buffering agents, neutralizing agents, antifoaming agents and stabilizers can be appropriately used.

  Examples of the polymerization initiator used in the present invention include 2,2′-azobisisobutyronitrile, 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydro Chloride, 2,2′-azobis (2-methylpropionamidine) disulfate, 2,2′-azobis (2-methylpropionamidine) dihydrochloride, 2,2′-azobis (N, N′-dimethyleneisobutyl) Azo initiators such as amidine) dihydrochloride, 2,2′-azobis [N- (2-carboxyethyl) -2-methylpropionamidine] hydrate, persulfates such as potassium persulfate and ammonium persulfate, di ( 2-ethylhexyl) peroxydicarbonate, di (4-t-butylcyclohexyl) peroxydicarbonate, di-se -Butyl peroxydicarbonate, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1 , 3,3-tetramethylbutylperoxy-2-ethylhexanoate, di (4-methylbenzoyl) peroxide, benzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di (t-hexylper Peroxides such as oxy) cyclohexane, t-butyl hydroperoxide, hydrogen peroxide, peroxides and sodium bisulfite, peroxides and sodium ascorbate, peroxides and reducing agents Redox initiators combined with Not intended to be.

  Although the said polymerization initiator may be used individually and may be used in mixture of 2 or more types, the content as a whole is usually 0.001-0. 1 part by weight is preferable, and 0.002 to 0.05 part by weight is more preferable.

  In the present invention, a chain transfer agent may be used in the polymerization. By using these chain transfer agents, the molecular weight of the (meth) acrylic polymer can be adjusted.

  Examples of the chain transfer agent include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol.

  These chain transfer agents may be used alone or as a mixture of two or more, but the total content is 0.01 to 1 weight with respect to 100 parts by weight of the monomer. Part.

  In the pressure-sensitive adhesive composition of the present invention, a pressure-sensitive adhesive sheet having further excellent heat resistance can be obtained by appropriately crosslinking a (meth) acrylic polymer. Specific means of the crosslinking method include an isocyanate compound, an epoxy compound, a melamine resin, an aziridine compound, a carbodiimide compound, a metal chelate compound, a carboxyl group and a hydroxyl group that are appropriately included in the (meth) acrylic polymer as a crosslinking base point. There is a method using a so-called cross-linking agent in which a compound having a group capable of reacting with an amino group, an amide group or the like is added and reacted. These compounds may be used alone or in combination of two or more.

  Furthermore, in the pressure-sensitive adhesive composition of the present invention, it is preferable to use a water-soluble crosslinking agent because a water-dispersed (meth) acrylic polymer is used as a base polymer.

  Examples of water-soluble crosslinking include epoxy compounds such as polyethylene glycol glycidyl ether, water-dispersed isocyanate compounds, oxazoline compounds, aziridine compounds, hydrophilized carbodiimide compounds, active methylol compounds, active alkoxymethyl compounds, and metal chelate compounds. be able to.

  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 by 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 (meth) acrylic polymer. More preferably, it is contained in an amount of 5 to 10 parts by weight. When the content is less than 0.01 parts by weight, the crosslinking formation by the crosslinking agent becomes insufficient, the cohesive strength of the pressure-sensitive adhesive composition becomes small, and sufficient heat resistance may not be obtained. There is a tendency to cause the rest. On the other hand, when the content exceeds 15 parts by weight, the cohesive force of the polymer is large, the fluidity is lowered, the wettability to the adherend is insufficient, and it tends to cause peeling.

  Furthermore, the pressure-sensitive adhesive composition used in the pressure-sensitive adhesive sheet of the present invention includes various conventionally known tackifiers, surface lubricants, surfactants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers. Depending on the use of various conventionally known additives such as additives, polymerization inhibitors, silane coupling agents, inorganic or organic fillers, powders such as metal powders and pigments, particulates and foils Can be added as appropriate.

  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 sheet of the present invention is 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.

  The method for forming the pressure-sensitive adhesive layer on the film is not particularly limited. For example, the pressure-sensitive adhesive composition is applied to the support film, and the polymerization solvent (water or aqueous solution) is removed by drying to remove the pressure-sensitive adhesive layer from the film. It is produced by forming. Thereafter, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction. In addition, when a pressure-sensitive adhesive composition is coated on a support film to produce a pressure-sensitive adhesive sheet, 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. May be added.

  Moreover, as a formation method of the adhesive layer of this invention, the well-known method used for manufacture of an adhesive sheet is used. Specific examples include roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, impregnation and curtain coating, and extrusion coating using a die coater.

  The pressure-sensitive adhesive sheet of the present invention has a variety of supports made of a plastic film such as a polyester film or a porous material such as paper or nonwoven fabric so that the pressure-sensitive adhesive layer 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 or film. For example, polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, polybutadiene film , Polyolefin films such as polymethylpentene film, ethylene / propylene copolymer, ethylene / 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl alcohol copolymer, Polyester film such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polyacrylate film, polyurethane film, polystyrene film, nylon 6, nylon 6,6, poly, such as partially aromatic polyamide Bromide films, polyvinyl chloride film, a vinyl chloride copolymer film, a polyvinylidene chloride film, and a polycarbonate film.

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

  Moreover, as a plastic substrate, a multilayer film formed by laminating a plastic substrate such as a polarizing plate, a retardation plate, a brightness enhancement plate, and an antiglare sheet can be used.

  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, sulfates, phosphonates, phosphates, alkylbetaines and their derivatives, imidazolines and their derivatives, and amphoteric antistatics such as alanine and their derivatives 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 copolymer having quaternary, styrene copolymer having quaternary ammonium group such as polyvinylbenzyltrimethylammonium chloride, diallylamine copolymer having quaternary ammonium group 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 for forming the antistatic layer, known coating methods are appropriately used. Specifically, for example, roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating method, impregnation and curtain Examples thereof include a coating method and an extrusion coating method using a die coater.

  The thickness of the antistatic resin layer, the conductive polymer, and the conductive resin is usually 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.

  In the pressure-sensitive adhesive sheet of the present invention, a separator (or a release liner, a release sheet, etc.) 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-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, or the like.

  The pressure-sensitive adhesive composition, the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive sheet using the present invention are used for plastic products that are particularly prone to generate static electricity, and in particular, antistatic properties used for applications that dislike static electricity in electronic devices. It is useful as an adhesive sheet and a surface protective film.

  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 glass transition temperature (Tg)>
The glass transition temperature Tg (° C.) was determined by the following formula using the following literature values as the glass transition temperature Tgn (° C.) of the homopolymer of each monomer.
Formula: 1 / (Tg + 273) = Σ [Wn / (Tgn + 273)]
[Wherein, Tg (° C.) is the glass transition temperature of the copolymer, Wn (−) is the 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
n-butyl acrylate: -55 ° C
n-Butyl methacrylate: 20 ° C
Acrylic acid: 106 ° C

<Preparation of acrylic polymer>
(Acrylic polymer (A))
In a reaction vessel equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel, 59 parts by weight of n-butyl acrylate, 40 parts by weight of n-butyl methacrylate, 1 part by weight of acrylic acid, an anionic reaction as an emulsifier 2 parts by weight of a functional emulsifier (Daiichi Kogyo Seiyaku Co., Ltd., Aqualon BC2020) and 0.6 parts by weight of polyoxyethylene alkyl phosphate ester type emulsifier (Toho Chemical Industries, Ltd., Phosphanol RE-410) were charged with 150 parts of water. Emulsified in parts by weight and purged with nitrogen for 2 hours. Next, after the temperature was raised to 55 ° C., 0.03 part by weight of 2,2′-azobis (2-methylpropionamidine) dihydrochloride was charged as a polymerization initiator, and nitrogen gas was introduced while gently stirring. The polymerization temperature was maintained at 55 ° C. for 8 hours to carry out the polymerization reaction. Then, it cooled to room temperature and neutralized with 10 weight% ammonia water, and prepared the water-dispersed acrylic polymer (A) solution. This acrylic polymer (A) had Tg = −29 ° C. and an acid value of 7.5.

(Acrylic polymer (B))
In a reaction vessel equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, a cooler, and a dropping funnel, 49.5 parts by weight of 2-ethylhexyl acrylate, 49.5 parts by weight of n-butyl methacrylate, 1 part by weight of acrylic acid, emulsifier As an anionic reactive emulsifier (Daiichi Kogyo Seiyaku Co., Ltd., Aqualon BC2020), 2 parts by weight were charged, emulsified in 150 parts by weight of water, and purged with nitrogen for 2 hours. Next, after the temperature was raised to 55 ° C., 0.03 part by weight of 2,2′-azobis (2-methylpropionamidine) dihydrochloride was charged as a polymerization initiator, and nitrogen gas was introduced while gently stirring. The polymerization temperature was maintained at 55 ° C. for 8 hours to carry out the polymerization reaction. Then, it cooled to room temperature and neutralized with 10 weight% ammonia water, and prepared the water-dispersed acrylic polymer (B) solution. This acrylic polymer (B) had Tg = −32 ° C. and an acid value of 7.6.

(Acrylic polymer (C))
In a reaction vessel equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel, 96 parts by weight of 2-ethylhexyl acrylate, 4 parts by weight of acrylic acid, an anionic emulsifier (made by Daiichi Kogyo Seiyaku Co., Ltd., Haitenol N-17) 3 parts by weight was charged, emulsified in 153 parts by weight of water, and purged with nitrogen for 2 hours. Next, 0.03 part by weight of 2,2′-azobis (2-methylpropionamidine) dihydrochloride as a polymerization initiator was charged, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at 55 ° C. The polymerization reaction was carried out for 7 hours. Then, it cooled to room temperature and neutralized with 10 weight% ammonia water, and prepared the water-dispersed acrylic polymer (C) solution. This acrylic polymer (C) had Tg = −66 ° C. and an acid value of 30.

(Acrylic polymer (D))
In a reaction vessel equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel, 96 parts by weight of n-butyl acrylate, 4 parts by weight of acrylic acid, an anionic emulsifier (made by Daiichi Kogyo Seiyaku Co., Ltd., Haitenol N-17) 3 parts by weight was charged, emulsified in 153 parts by weight of water, and purged with nitrogen for 2 hours. Next, 0.03 part by weight of 2,2′-azobis (2-methylpropionamidine) dihydrochloride as a polymerization initiator was charged, nitrogen gas was introduced while gently stirring, and the liquid temperature in the flask was maintained at 55 ° C. The polymerization reaction was carried out for 7 hours. Then, it cooled to room temperature and neutralized with 10 weight% ammonia water, and prepared the water-dispersed acrylic polymer (D) solution. This acrylic polymer (D) had Tg = −51 ° C. and an acid value of 31.

<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)
1-butyl-3-methylpyridinium trifluoromethanesulfonate (Nippon Carlit Co., Ltd., BMP-Trf, water-soluble, liquid at 25 ° C. as an antistatic agent based on 100 parts by weight of the solid content of the acrylic polymer (A) solution ) 5 parts by weight, 10 parts by weight of an oxazoline group-containing water-soluble crosslinking agent (Nippon Shokubai Co., Ltd., Epocros WS-500, 40% by weight) is added as a crosslinking agent, followed by mixing and stirring at 25 ° C. for about 1 minute. A dispersion type acrylic pressure-sensitive adhesive solution (1) was prepared. A 10% by weight aqueous solution of BMP-Trf was prepared and confirmed to be water-soluble.

(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 15-micrometer-thick adhesive layer. Next, a pressure-sensitive adhesive sheet was prepared by laminating a silicone-treated surface of a 25 μm-thick polyethylene terephthalate film having one surface subjected to silicone treatment on the surface of the pressure-sensitive adhesive layer.

[Example 2]
(Preparation of adhesive composition)
A water-dispersed acrylic pressure-sensitive adhesive solution (2) was prepared in the same manner as in Example 1 except that the acrylic polymer (B) was used instead of the acrylic polymer (A).

(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).

[Comparative Example 1]
(Preparation of adhesive composition)
A water-dispersed acrylic pressure-sensitive adhesive similar to Example 1 except that the 1-butyl-3-methylpyridinium trifluoromethanesulfonate (Nippon Carlit Co., Ltd., BMP-Trf, liquid at 25 ° C.) was not used. Solution (3) was prepared.

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

[Comparative Example 2]
(Preparation of adhesive composition)
A water-dispersed acrylic pressure-sensitive adhesive in the same manner as in Example 2 except that the 1-butyl-3-methylpyridinium trifluoromethanesulfonate (Nippon Carlit, BMP-Trf, liquid at 25 ° C.) was not used. Solution (4) was prepared.

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

[Comparative Example 3]
(Preparation of adhesive composition)
Instead of 5 parts by weight of 1-butyl-3-methylpyridinium trifluoromethanesulfonate (Nippon Carlit, liquid at 25 ° C), n-lauryltrimethylammonium chloride (Tokyo Chemical Industry, solid at 80 ° C) ) An attempt was made to prepare a water-dispersed acrylic pressure-sensitive adhesive solution (5) in the same manner as in Example 1 except that 5 parts by weight were used. However, in the above-mentioned acrylic pressure-sensitive adhesive solution (5), aggregation occurred. It was.

(Preparation of adhesive sheet)
In the said acrylic adhesive solution (5), since aggregation occurred, the adhesive sheet was not able to be created.

Example 3
(Preparation of adhesive composition)
A water-dispersed acrylic pressure-sensitive adhesive solution (6) was prepared in the same manner as in Example 1 except that the acrylic polymer (C) was used instead of the acrylic polymer (A).

(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 4
(Preparation of adhesive composition)
Instead of the acrylic polymer (A), 1-butyl-3-methylpyridinium trifluoromethanesulfonate (manufactured by Nippon Carlit Co., Ltd., BMP) was used as an antistatic agent with respect to 100 parts by weight of the solid content of the acrylic polymer (D) solution. -Trf, water-soluble, liquid at 25 ° C.) 4 parts by weight, except that 5 parts by weight of an oxazoline group-containing water-soluble crosslinking agent (manufactured by Nippon Shokubai Co., Ltd., Epokuguchi WS-500, 40% by weight) was added as a crosslinking agent In the same manner as in Example 1, a water-dispersed acrylic pressure-sensitive adhesive solution (7) was prepared.

(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 5
(Preparation of adhesive composition)
Instead of the acrylic polymer (A), the acrylic polymer (C) is used as the antistatic agent, and the 1-butyl-3-methylpyridinium trifluoromethanesulfonate (manufactured by Nippon Carlit Co., Ltd., BMP-Trf, water-soluble, Except that 5 parts by weight of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd., water-soluble, liquid at 25 ° C) was used instead of 5 parts by weight. In the same manner as in Example 1, a water-dispersed acrylic pressure-sensitive adhesive solution (8) was prepared. A 10% by weight aqueous solution of 1-ethyl-3-methylimidazolium trifluoromethanesulfonate was prepared and confirmed to be water-soluble.

(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 6
(Preparation of adhesive composition)
Instead of the acrylic polymer (A), the 1-butyl-3-methylpyridinium trifluoromethanesulfonate (BMP, manufactured by Nippon Carlit Co., Ltd.) was used as an antistatic agent with respect to 100 parts by weight of the solid content of the acrylic polymer (C) solution. -Trf, water-soluble, liquid at 25 ° C.) 1-butyl-3-methylimidazolium trifluoromethanesulfonate (Acros Organics, water-soluble, liquid at 25 ° C.) 2.5 wt. A water-dispersed acrylic pressure-sensitive adhesive solution (9) was prepared in the same manner as in Example 1 except that the parts were used. A 10% by weight aqueous solution of 1-butyl-3methylimidazolium trifluoromethanesulfonate was prepared and confirmed to be water-soluble.

(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).

Example 7
(Preparation of adhesive composition)
Instead of the acrylic polymer (A), the 1-butyl-3-methylbilidinium trifluoromethanesulfonate (Nippon Carlit Co., Ltd.) was used as an antistatic agent with respect to 100 parts by weight of the solid content of the acrylic polymer (C) solution. BMP-Trf, water-soluble, liquid at 25 ° C.) instead of 5 parts by weight 9-weight of 1-hexyl-3-methylimidazolium bromide (Acros Organics, water-soluble, liquid at 25 ° C.) A water-dispersed acrylic pressure-sensitive adhesive solution (10) was prepared in the same manner as in Example 1 except that the parts were used. A 10% by weight aqueous solution of 1-hexyl-3-methylimidazolium bromide was prepared and confirmed to be water-soluble.

(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 4]
(Preparation of adhesive composition)
Water-dispersed acrylic adhesive in the same manner as in Example 3 except that the above 1-butyl-3-methylpyridinium trifluoromethanesulfonate (manufactured by Nippon Ritto Co., Ltd., BMP-Trf, liquid at 25 ° C.) was not used. An agent solution (11) was prepared.

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

[Comparative Example 5]
(Preparation of adhesive composition)
A water-dispersed acrylic adhesive in the same manner as in Example 4 except that 1-butyl-3-methylpyridinium trifluoromethanesulfonate (manufactured by Nippon Ritto Co., Ltd., BMP-Trf, liquid at 25 ° C.) was not used. An agent solution (12) was prepared.

(Preparation of adhesive sheet)
A pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the acrylic pressure-sensitive adhesive solution (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, contamination | contamination property, adhesive force, and generation | occurrence | production of aggregation were evaluated in the following way.

<Measurement of peeling voltage>
The prepared pressure-sensitive adhesive sheet was cut into a size of 70 mm in width and 130 mm in length, the separator was peeled off, and then an acrylic plate (Mitsubishi Rayon Co., Acrylite, thickness: 1 mm, width: 70 mm, length previously removed) : 100 mm) or a polarizing plate (SEG1425DU, manufactured by Nitto Denko Co., Ltd.) bonded to an acrylic plate (Mitsubishi Rayon Co., acrylite, thickness: 1 mm, width: 70 mm, length: 100 mm) previously neutralized. (Width: 70 mm, length: 100 mm) The surface was crimped with a hand roller so that one end protruded 30 mm.

  After being left for one day in an environment of 23 ° C. × 50% RH, a sample is set at a predetermined position as shown in FIGS. One end protruding 30 mm was fixed to an automatic winder, and peeled so that the peeling angle was 150 ° and the peeling speed was 10 m / min. Measured with a potential measuring instrument (KSD-0103, manufactured by Kasuga Denki Co., Ltd.) in which the potential of the acrylic plate surface or the polarizing plate surface and the potential of the adhesive sheet surface generated at this time are fixed at the center position in the sample length direction. did. The distance between the sample and the potential measuring device was 100 mm when measuring the acrylic plate surface or polarizing plate surface, and 50 mm when measuring the adhesive sheet surface. The measurement was performed in an environment of 23 ° C. × 50% RH.

<Evaluation of contamination>
The prepared adhesive sheet is cut to a size of 50 mm in width and 80 mm in length, and the separator is peeled off. Then, the acrylic sheet (manufactured by Mitsubishi Rayon Co., Acrylite, thickness: 1 mm, width: 70 mm, length: 100 mm) is handed on the surface. An evaluation sample was prepared by pressure bonding with a roller.

After this evaluation sample was left in an environment of 23 ° C. × 50% RH for 24 hours, the pressure-sensitive adhesive sheet was peeled off from the adherend by hand, and the contamination state of the adherend surface at that time was visually observed and evaluated. . The evaluation criteria are as follows.
If no contamination was found: ○
If contamination is found: ×

<Adhesion measurement>
The prepared pressure-sensitive adhesive sheet was pressed to a size of 25 mm in width and 100 mm in length, and the separator was peeled off. Then, a pressure of 0.25 MPa was applied to the polarizing plate (manufactured by Nitto Denko Corporation, SEG1425DU, width: 70 mm, length: 100 mm). Was laminated to prepare an evaluation sample.

  After lamination, the laminate was allowed to stand in an environment of 23 ° C. × 50% RH for 30 minutes, and then the adhesive strength when peeled at a peeling speed of 10 m / min and a peeling angle of 180 ° C. was measured with a universal tensile tester. The measurement was performed in an environment of 23 ° C. × 50% RH.

<Evaluation of cohesiveness>
The prepared acrylic pressure-sensitive adhesive solution was visually observed and evaluated for the presence of cohesiveness. The evaluation criteria are as follows.
When aggregation is not recognized: ○
When aggregation is observed: ×

  The results are shown in Table 1.

  When the pressure-sensitive adhesive composition prepared according to the present invention was used according to the results of Table 1 above (Examples 1 to 7), in any of the Examples, the peeling voltage of the pressure-sensitive adhesive sheet itself after peeling the pressure-sensitive adhesive sheet, Further, it was revealed that the peeling voltage of the acrylic plate and the polarizing plate is suppressed, no contamination occurs, no aggregation occurs, and the adhesion reliability is excellent.

  On the other hand, in the case where no ionic liquid was used as the antistatic agent (Comparative Examples 1-2, 4-5), in all cases, the peeling voltage of the acrylic plate and the polarizing plate was high. In addition, when a surfactant was used as an antistatic agent (Comparative Example 3), it was found that aggregation occurred in the acrylic pressure-sensitive adhesive solution and a pressure-sensitive adhesive sheet could not be produced. Therefore, in all of the comparative examples, the result is that the pressure-sensitive adhesive sheet and the acrylic plate, the suppression of the stripping voltage of the polarizing plate, and the suppression of the occurrence of aggregation cannot be made side by side, and the antistatic pressure-sensitive adhesive composition for the pressure-sensitive adhesive sheet It became clear that it was not suitable.

Schematic configuration diagram of potential measurement unit used for measurement of peeling voltage in Example Schematic configuration diagram of potential measurement unit used for measurement of peeling voltage in Example

Claims (7)

  A water-dispersed (meth) acrylic polymer containing 50 to 99.9% by weight of a (meth) acrylate having an alkyl group having 1 to 14 carbon atoms as a monomer component, and an ionic liquid A pressure-sensitive adhesive 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 pressure-sensitive adhesive composition according to claim 1, wherein the ionic liquid is a water-soluble ionic liquid.   The adhesive layer formed by bridge | crosslinking the adhesive composition in any one of Claims 1-4.   A pressure-sensitive adhesive sheet obtained by forming a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition according to claim 1 on one side or both sides of a support.   A surface protective film comprising a pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition according to any one of claims 1 to 4 formed on one side or both sides on a support made of a plastic substrate. .

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