JP4805062B2 - Adhesive composition and adhesive sheet - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition having antistatic properties and antistatic pressure-sensitive adhesive sheets made into a form such as a sheet or a tape using the same. The pressure-sensitive adhesive sheets comprising the antistatic pressure-sensitive adhesive composition of the present invention are suitably used for plastic products and the like that are likely to generate static electricity. Especially, it is useful as a surface protective film used for the purpose of protecting optical member surfaces, such as a polarizing plate, a wavelength plate, an optical compensation film, and a reflective sheet.

  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 protective film is bonded to an optical member such as a polarizing plate or a wave plate used for a liquid crystal display panel 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 surface protective film in which an antistatic layer is provided on one side of a plastic film is disclosed (for example, see Patent Document 1). However, in this surface protection film, since the antistatic treatment is performed on the support side, the surface protection film side can be prevented from being charged, but the protected body cannot be prevented from being charged. There was a problem that the object to be protected was charged when it was peeled off.

  Further, a method is disclosed in which a cationic surfactant or the like is added to the pressure-sensitive adhesive, and the surfactant is transferred from the pressure-sensitive adhesive to the adherend to prevent charging (for example, see Patent Document 2). However, this invention is an invention in which a surfactant is bleed on the surface of an adhesive and transferred to an adherend, and when applied to a protective film, contamination of the adherend is inevitable. Therefore, when the adhesive to which a low molecular surfactant is added is applied to the protective film for an optical member, there is a problem of impairing the optical characteristics of the optical member.

  Furthermore, 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 3). . However, even with this method, bleeding of the antistatic agent is unavoidable, and it has been found that when applied to a surface protective film, contamination of the adherend occurs over time or at high temperatures.

JP 11-256116 A JP-A-9-165460 JP-A-6-128539

  In light of such circumstances, the present invention provides a pressure-sensitive adhesive composition capable of preventing the adherend from being charged when peeled and reducing the contamination of the adherend, and an antistatic adhesive using the same. The purpose is to provide sheets.

  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 comprises an ionic liquid and an acrylic having an acid value of 1.0 or less, the main component being one or more of acrylates and / or methacrylates having an alkyl group having 1 to 14 carbon atoms. It is characterized by containing a system polymer. Here, the ionic liquid refers to a molten salt (ionic compound) that is liquid at room temperature (25 ° C.). The acid value means the number of mg of potassium hydroxide required to neutralize free fatty acid, resin acid, etc. contained in 1 g of a sample, and specifically measured by the method described in the Examples. Is the value to be

  According to the present invention, the above ionic liquid acts as an antistatic agent, and by using this ionic liquid, the antistatic agent bleed is suppressed, and the adhesion to the adherend is low even over time and at high temperatures. An agent composition is obtained. Although the details of the reason why bleeding is suppressed by using an ionic liquid are not clear, it is presumed as follows. It is considered that the antistatic effect by the surfactant having a long chain alkyl group or the like is manifested by the surface of the surfactant bleed and the formation of a charge leakage layer with moisture in the air. On the other hand, since the ionic liquid is in a liquid state, the molecular movement is easier than that of the surfactant, and the rearrangement of molecules is likely to occur due to the generation of electric charges. Therefore, in the case of an ionic liquid, since a charge neutralization mechanism by molecular rearrangement works, it is considered that an excellent antistatic effect can be obtained without bleed on the surface as compared with the surfactant. Further, since the ionic liquid is preferably in a liquid state at room temperature, it can be easily added to, dispersed in, or dissolved in the pressure-sensitive adhesive as compared with a solid salt. Further, since the ionic liquid has no vapor pressure (non-volatile), it has a characteristic that the antistatic property is continuously obtained without disappearing with time.

  At that time, since the acid value of the acrylic polymer is 1.0 or less, it has substantially no acid functional group having a large interaction with the ionic liquid. The antistatic function can be suitably expressed without inhibiting the sum mechanism. Further, since an acrylic polymer having an alkyl group having a specific carbon number is used, the compatibility with the ionic liquid is good and the balance of the adhesive property is excellent.

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

［式（Ａ）中のＲ₁は、炭素数４から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ₂およびＲ₃は、同一又は異なって、水素または炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。但し、窒素原子が２重結合を含む場合、Ｒ_３はない。］
［式（Ｂ）中のＲ₄は、炭素数２から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ₅、Ｒ₆、およびＲ₇は、同一又は異なって、水素または炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。］
［式（Ｃ）中のＲ₈は、炭素数２から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ₉、Ｒ₁₀、およびＲ₁₁は、同一又は異なって、水素または炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。］
［式（D）中のXは、窒素、硫黄、又はリン原子を表し、Ｒ₁₂、Ｒ₁₃、Ｒ₁₄、およびＲ₁₅は、同一又は異なって、炭素数１から２０の炭化水素基を表し、ヘテロ原子を含んでも良い。但しＸが硫黄原子の場合、Ｒ₁₂はない。］。

[R ₁ in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms and may contain a hetero atom, and R ₂ and R ₃ may be the same or different and each may be hydrogen or 1 to 16 carbon atoms. It represents a hydrocarbon group and may contain a hetero atom. However, when the nitrogen atom contains a double bond, there is no R ₃ . ]
[R ₄ in the formula (B) represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a hetero atom, and R ₅ , R ₆ , and R ₇ may be the same or different and each may represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[R ₈ in Formula (C) represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a hetero atom, and R ₉ , R ₁₀ , and R ₁₁ may be the same or different and each may represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[X in the formula (D) represents a nitrogen, sulfur, or phosphorus atom, and R ₁₂ , R ₁₃ , R ₁₄ , and R ₁₅ are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms. , And may contain a heteroatom. However, when X is a sulfur atom, there is no R ₁₂ . ].

  On the other hand, the pressure-sensitive adhesive sheets of the present invention have a pressure-sensitive adhesive layer containing any one of the pressure-sensitive adhesive compositions described above on one side or both sides of a support. According to the pressure-sensitive adhesive sheets of the present invention, since the pressure-sensitive adhesive composition of the present invention having the above-described effects is used, the adherend can be prevented from being charged when peeled, and the contamination to the adherend is reduced. Possible adhesive sheets can be obtained.

  Moreover, it is preferable that the said support body is equipped with the plastic film by which antistatic treatment was carried out. By subjecting the plastic film to an antistatic treatment, the withstand voltage to peel off the adherend can be made within ± 0.5 kV, and the antistatic property is further improved.

  The pressure-sensitive adhesive composition of the present invention contains an ionic liquid and an acrylic polymer containing as a main component at least one of acrylate and / or methacrylate having an alkyl group having 1 to 14 carbon atoms.

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

［式（Ａ）中のＲ₁は、炭素数４から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ₂およびＲ₃は、同一又は異なって、水素または炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。但し、窒素原子が２重結合を含む場合、Ｒ_３はない。］
［式（Ｂ）中のＲ₄は、炭素数２から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ₅、Ｒ₆、およびＲ₇は、同一又は異なって、水素または炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。］
［式（Ｃ）中のＲ₈は、炭素数２から２０の炭化水素基を表し、ヘテロ原子を含んでも良く、Ｒ₉、Ｒ₁₀、およびＲ₁₁は、同一又は異なって、水素または炭素数１から１６の炭化水素基を表し、ヘテロ原子を含んでも良い。］
［式（D）中のXは、窒素、硫黄、又はリン原子を表し、Ｒ₁₂、Ｒ₁₃、Ｒ₁₄、およびＲ₁₅は、同一又は異なって、炭素数１から２０の炭化水素基を表し、ヘテロ原子を含んでも良い。但しＸが硫黄原子の場合、Ｒ₁₂はない。］。

[R ₁ in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms and may contain a hetero atom, and R ₂ and R ₃ may be the same or different and each may be hydrogen or 1 to 16 carbon atoms. It represents a hydrocarbon group and may contain a hetero atom. However, when the nitrogen atom contains a double bond, there is no R ₃ . ]
[R ₄ in the formula (B) represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a hetero atom, and R ₅ , R ₆ , and R ₇ may be the same or different and each may represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[R ₈ in Formula (C) represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a hetero atom, and R ₉ , R ₁₀ , and R ₁₁ may be the same or different and each may represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[X in the formula (D) represents a nitrogen, sulfur, or phosphorus atom, and R ₁₂ , R ₁₃ , R ₁₄ , and R ₁₅ are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms. , And may contain a heteroatom. However, when X is a sulfur atom, there is no R ₁₂ . ].

  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 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-propylpyrrolidinium cation 2-methyl-1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, and 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 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl- 3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazolium cation 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3-dimethyl Imidazolium cation, 1,3-dimethyl-1,4 5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4,5,6 -Tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1, 3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation And the like.

  Examples of the cation represented by the formula (C) include a pyrazolium cation and a virazolinium cation. Specific examples include 1-methylpyrazolium cation, 3-methylpyrazolium cation, 1-ethyl-2-methylpyrazolinium cation and the like.

  Examples of the cation represented by the formula (D) include a tetraalkylammonium cation, a trialkylsulfonium cation, a tetraalkylphosphonium cation, and those in which a part of the alkyl group is substituted with an alkenyl group, an alkoxyl group, or an epoxy group. Is mentioned.

  Specific examples include tetramethylammonium cation, tetraethylammonium cation, tetrabutylammonium cation, tetrahexylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethyldecylammonium cation, N, N-diethyl-N-methyl-N -(2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, N, N-dimethyl-N, N-dipropylammonium cation, N, N-dimethyl-N, N-dihexylammonium cation, N, N-dipropyl- N, N-dihexylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, Silsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrahexylphosphonium cation, triethylmethylphosphonium cation, tributylethylphosphonium cation, trimethyldecyl Examples include phosphonium cations and diallyldimethylammonium cations.

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

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

  Specific examples of the ionic liquid used in the present invention are appropriately selected from the combination of the cation component and the anion component, and include 1-butylpyridinium tetrafluoroborate, 1-butylpyridinium hexafluorophosphate, 1-butyl- 3-methylpyridinium tetrafluoroborate, 1-butyl-3-methylpyridinium trifluoromethanesulfonate, 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide, 1-butyl-3-methylpyridinium bis (pentafluoroethanesulfonyl) ) Imido, 1-hexylpyridinium tetrafluoroborate, 2-methyl-1-pyrroline tetrafluoroborate, 1-ethyl-2-phenylindole tetrafluoroborate, 1,2-dimethyli Dole tetrafluoroborate, 1-ethylcarbazole tetrafluoroborate, 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-ethyl-3-methylimidazolium acetate, 1-ethyl-3-methylimidazolium trifluoroacetate, 1-ethyl-3-methylimidazolium heptafluorobutyrate, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, 1-ethyl-3-methylimidazolium perfluorobutanesulfonate, 1-ethyl-3-methylimidazolium di Cyanamide, 1-ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide, 1-ethyl-3-methylimidazolium bis (pentafluoroethanesulfonyl) imide, 1-ethyl 3-methylimidazolium tris (trifluoromethanesulfonyl) imide, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate, 1-butyl-3-methylimidazolium trifluoro Acetate, 1-butyl-3-methylimidazolium heptafluorobutyrate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, 1-butyl-3-methylimidazolium perfluorobutanesulfonate, 1-butyl-3-methylimidazole Bis (trifluoromethanesulfonyl) imide, 1-hexyl-3-methylimidazolium bromide, 1-hexyl-3-methylimidazolium chloride, 1-hexyl-3-methylimidazolium 1-hexyl-3-methylimidazolium hexafluorophosphate, 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, 1-octyl-3-methylimidazolium tetrafluoroborate, 1-octyl- 3-methylimidazolium hexafluorophosphate, 1-hexyl-2,3-dimethylimidazolium tetrafluoroborate, 1,2-dimethyl-3-propylimidazolium bis (trifluoromethanesulfonyl) imide, 1-methylpyrazolium Tetrafluoroborate, 3-methylpyrazolium tetrafluoroborate, tetrahexylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N- (2-methoxyethyl) a Monium tetrafluoroborate, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide, diallyldimethylammonium tetrafluoroborate, diallyldimethylammonium trifluoromethanesulfonate, diallyldimethylammonium bis (Trifluoromethanesulfonyl) imide, diallyldimethylammonium bis (pentafluoroethanesulfonyl) imide, glycidyltrimethylammonium trifluoromethanesulfonate, glycidyltrimethylammonium bis (trifluoromethanesulfonyl) imide, glycidyltrimethylammonium bis (pentafluoroethanesulfonyl) imide, 1 -Butylpyridinium (trifluoromethanes Phonyl) trifluoroacetamide, 1-butyl-3-methylpyridinium (trifluoromethanesulfonyl) trifluoroacetamide, 1-ethyl-3-methylimidazolium (trifluoromethanesulfonyl) trifluoroacetamide, diallyldimethylammonium (trifluoromethanesulfonyl) tri Fluoroacetamide, glycidyltrimethylammonium (trifluoromethanesulfonyl) trifluoroacetamide, N, N-dimethyl-N-ethyl-N-propylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-butyl Ammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-pentylammonium bis (trifluoromethane Sulfonyl) imide, N, N-dimethyl-N-ethyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-ethyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N , N-dimethyl-N-ethyl-N-nonylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N, N-dipropylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N- Propyl-N-butylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-hexylammonium Screw Fluoromethanesulfonyl) imide, N, N-dimethyl-N-propyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-butyl-N-heptylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl-N-pentyl-N-hexylammonium bis (trifluoromethanesulfonyl) imide, N, N-dimethyl- N, N-dihexylammonium bis (trifluoromethanesulfonyl) imide, trimethylheptylammonium bis (trifluoromethanesulfonyl) imide, N, N-diethyl-N-methyl-N-propylammonium bis (trifluoro) Romethanesulfonyl) 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 (trifluoromethane) Sulfonyl) 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-hexylammonium bis (trifluoromethanesulfonyl) imide , Trioctylmethylammonium bis (trifluoromethanesulfonyl) imide, N-methyl-N-ethyl-N-propyl-N-pentylammonium bis (trifluoromethanesulfonyl) imide, and the like.

  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), chlorine, bromine and iodine are used as the halogen) Acid (HA) or salt (MA, M) having an anion structure (A ⁻ ) of the ionic liquid intended for the obtained halide Is reacted with a target anion such as ammonium, lithium, sodium, potassium, etc. to form a salt, and the target ionic liquid (R ₄ NA) is obtained.

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

The acid ester method is a method performed by reactions as shown in (9) to (11). First, a tertiary amine (R ₃ N) is reacted with an acid ester to obtain an acid ester product. (Reaction formula (9), as the acid ester, an ester of an inorganic acid such as sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid or carbonic acid, or an organic acid such as methanesulfonic acid, methylphosphonic acid or formic acid) The target ionic liquid (R ₄ NA) is obtained by using the obtained acid ester product in 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)) The obtained quaternary ammonium fluoride salt is subjected to a complex formation reaction with fluorides such as BF ₃ , AlF ₃ , PF ₅ , ASF ₅ , SbF ₅ , NbF ₅ , and TaF _5. An ionic liquid can be obtained. (Reaction formula (15)).

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

  R described above represents hydrogen or a hydrocarbon group having 1 to 20 carbon atoms, and may contain a hetero atom.

  The blending amount of the ionic liquid cannot be defined unconditionally because it varies depending on the compatibility of the acrylic polymer to be used and the ionic liquid, but is generally 0.01 to 100 parts by weight of the base polymer. 40 parts by weight is preferable, 0.03 to 20 parts by weight is more preferable, and 0.05 to 10% 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 this invention, the acrylic polymer which has as a main component 1 type, or 2 or more types of the acrylate and / or methacrylate which have a C1-C14 alkyl group as a base polymer is contained. The acrylic polymer preferably has a glass transition point Tg of 0 ° C. or lower (usually −100 ° C. or higher) from the viewpoint of the balance of adhesive performance. From the same viewpoint, the alkyl group preferably has 6 to 14 carbon atoms.

  As an acrylic polymer mainly composed of one or more of acrylates and / or methacrylates having an alkyl group having 1 to 14 carbon atoms, acrylates and / or methacrylates having an alkyl group having 1 to 14 carbon atoms { Hereinafter referred to as (meth) acrylate. } An acrylic polymer having a weight average molecular weight of 100,000 or more, the main component of which is a monomer containing 50 to 100% by weight of one or more of the above.

  Specific examples of the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, n-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 ( Examples include meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, and n-tetradecyl (meth) acrylate.

  The acid value of the acrylic polymer is 1.0 or less, preferably 0.8 or less, and most preferably 0.0. When the acid value exceeds 1.0, the amount of the acid functional group having an interaction with the ionic liquid increases, and the antistatic property becomes insufficient. The acid value of the acrylic polymer can be adjusted by reducing or reducing the amount of the monomer having a carboxyl group or a sulfonate group.

  Therefore, as other components constituting the acrylic polymer, any components other than acrylates and / or methacrylates having a carboxyl group or a sulfonate group can be used without any particular limitation. Among these, a hydroxyl group-containing monomer is preferable because crosslinking can be easily controlled, and an acrylate and / or methacrylate having a hydroxyl group is particularly preferable.

  As hydroxyl group-containing monomers, 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 vinyl ether, 4 -Hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and the like. The amount of the hydroxyl group-containing monomer used is preferably 0.5 to 10% by weight and more preferably 1 to 8% by weight in the constituent monomer components.

  Components other than the above hydroxyl group-containing monomers include cyano group-containing monomers such as acrylonitrile, vinyl esters such as vinyl acetate, cohesive force / heat resistance improving components such as aromatic vinyl compounds such as styrene, acrylamide, and diethylacrylamide. Amide group-containing monomers such as N, N-dimethylaminoethyl (meth) acrylate, amino group-containing monomers such as N, N-dimethylaminopropyl (meth) acrylate, and epoxy groups such as glycidyl (meth) acrylate and allyl glycidyl ether Examples thereof include a component having a functional group that serves as an adhesive strength improvement and a crosslinking base point, such as a vinyl monomer such as a containing monomer, N-acryloylmorpholine, and vinyl ethyl ether. The above components can be used alone or in combination of two or more.

  The pressure-sensitive adhesive of the present invention can obtain pressure-sensitive adhesive sheets having further excellent heat resistance by appropriately crosslinking an acrylic polymer. As specific means of the crosslinking method, a compound having a group capable of reacting with a hydroxyl group, an amino group, an amide group, or the like appropriately included as a crosslinking base point in an acrylic polymer such as a polyisocyanate compound, an epoxy compound, or an aziridine compound is added. There is a method using a so-called cross-linking agent that is reacted. Of these, polyisocyanate compounds and epoxy compounds are particularly preferably used.

  Examples of the polyisocyanate compound include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, 2,4-tolylene diisocyanate, Aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate and xylylene diisocyanate, trimethylolpropane / tolylene diisocyanate trimer adduct (trade name Coronate L), trimethylolpropane / hexamethylene diisocyanate trimer adduct ( Product name Coronate HL), isocyanurate of hexamethylene diisocyanate (Product name Coronate HX) Urethane Industry Co., Ltd.] and the like isocyanate adducts such as. Examples of the epoxy compound include N, N, N ′, N′-tetraglycidyl-m-xylenediamine (trade name: TETRAD-X) and 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (trade name: TETRAD- C) [all manufactured by Mitsubishi Gas Chemical Co., Ltd.]. These crosslinking agents are used alone or in a mixture of two or more. The amount of the crosslinking agent to be used is appropriately selected depending on the balance with the acrylic polymer to be crosslinked and, further, depending on the intended use as the pressure-sensitive adhesive sheet.

  In order to obtain sufficient heat resistance by the cohesive strength of the acrylic pressure-sensitive adhesive, it is generally preferable to add 0.5 parts by weight or more with respect to 100 parts by weight of the acrylic polymer. Moreover, it is preferable to mix | blend at 10 weight part or less with respect to 100 weight part of said acrylic polymers from the point of a softness | flexibility and adhesiveness.

  Moreover, it can also add as a polyfunctional monomer which has 2 or more of radiation reactive unsaturated bonds as a substantial crosslinking agent, and can also be bridge | crosslinked by radiation. The polyfunctional monomer having two or more radiation-reactive unsaturated bonds is one or more radiation reactions 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 properties is used. In general, those having 10 or less radiation-reactive unsaturated bonds are preferably used. Two or more polyfunctional monomers can be used in combination.

  Specific examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,6 hexanediol di ( And (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 acrylic polymer to be crosslinked and further depending on the intended use as an adhesive sheet. In general, in order to obtain sufficient heat resistance by the cohesive force of the acrylic pressure-sensitive adhesive, it is preferably blended at 0.1 to 30 parts by weight with respect to 100 parts by weight of the acrylic polymer. Moreover, it is more preferable to mix | blend at 10 weight part or less with respect to 100 weight part of acrylic polymers from the point of a softness | flexibility and adhesiveness.

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

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

  Examples of radical photopolymerization initiators include benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, o-benzoylbenzoic acid methyl-p-benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, benzyl dimethyl ketal, trichloroacetophenone 2,2-diethoxyacetophenone, acetophenones such as 1-hydroxycyclohexyl phenyl ketone, propio such as 2-hydroxy-2-methylpropiophenone, 2-hydroxy-4′-isopropyl-2-methylpropiophenone Benzophenones such as phenones, benzophenone, methylbenzophenone, p-chlorobenzophenone, p-dimethylaminobenzofuninone, 2-chlorothioxanthone, 2-ethylthioxone Thioxanthones such as N, 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, organometallic complexes such as iron-allene complexes, titanocene complexes, and arylsilanol-aluminum complexes, nitrobenzyl Examples thereof include esters, sulfonic acid derivatives, phosphoric acid esters, sulfonic acid derivatives, phosphoric acid esters, phenol sulfonic acid esters, diazonaphthoquinone, and N-hydroxyimide sulfonate. About the said photoinitiator, it is also possible to use 2 or more types together.

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

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

  Furthermore, the pressure-sensitive adhesive used in the pressure-sensitive adhesive sheet of the present invention includes various conventionally known tackifiers and surface lubricants, leveling agents, antioxidants, corrosion inhibitors, light stabilizers, ultraviolet absorbers, polymerization inhibitors, A silane coupling agent, an inorganic or organic filler, a powder such as a metal powder or a pigment, a particle, a foil, and the like may be added as appropriate according to the use for which various conventionally known additives are used. I can do it.

  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. Polyethylene, polypropylene, poly-1-butene, poly-4-methyl-1-pentene, ethylene / propylene Polymer, ethylene 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, ethylene / vinyl alcohol copolymer and other polyolefin films, polyethylene terephthalate, polyethylene naphthalate, polybutylene Polyester film such as terephthalate, polyacrylate film, polystyrene film, nylon 6, nylon 6,6, polyamide film such as partially aromatic polyamide, polyvinyl chloride film, polyvinylidene chloride film, polycarbonate Irumu and the like. The thickness of the film is usually about 5 to 200 μm, preferably about 10 to 100 μm.

  In addition, as the support used in the present invention, an antistatic treated plastic film is more preferably used. The antistatic treatment applied to the plastic film is not particularly limited, and 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 the plastic film is used. As a method of providing an antistatic layer on at least one surface of the film, an antistatic resin comprising an antistatic agent and a resin component, a conductive polymer, a method of applying a conductive resin containing a conductive material, or a conductive material is deposited. Or the method of plating is mention | raise | lifted.

  Antistatic agents 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 sulfonates. An anionic antistatic agent having an anionic functional group such as sulfate salt, phosphonate, phosphate ester salt, amphoteric antistatic agent such as alkylbetaine and its derivatives, imidazoline and its derivatives, alanine and its derivatives, Nonionic antistatic agents such as aminoalcohol and derivatives thereof, glycerin and derivatives thereof, polyethylene glycol and derivatives thereof, and monomers having an ion conductive group of the above cation type, anion type and zwitterionic type are polymerized or Examples thereof include ionic conductive polymers obtained by copolymerization. These compounds may be used alone or in combination of two or more.

  As a cationic type antistatic agent, for example, it has a quaternary ammonium group such as alkyltrimethylammonium salt, acyloylamidopropyltrimethylammonium methosulfate, alkylbenzylmethylammonium salt, acylcholine chloride, polydimethylaminoethyl methacrylate (meth) Examples thereof include acrylate copolymers, styrene copolymers having quaternary ammonium groups such as polyvinylbenzyltrimethylammonium chloride, and diallylamine copolymers having quaternary ammonium groups such as polydiallyldimethylammonium chloride. 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.

  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.

  As the resin component used for the antistatic resin and the conductive resin, 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 can contain a methylol- or alkylol-containing melamine-based, urea-based, glyoxal-based, acrylamide-based compound, epoxy compound, or isocyanate-based 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 coat method.

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

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

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

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

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

  As a method for forming and applying the pressure-sensitive adhesive, known methods used for the production of pressure-sensitive adhesive tapes are used. Specific examples include roll coating, gravure coating, reverse coating, roll brushing, spray coating, and air knife coating.

  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, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer. Examples thereof include a film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

  The thickness of the film is usually about 5 to 200 μm, preferably about 10 to 100 μm. The adhesive layer bonding surface of the film is appropriately treated with a release agent such as a silicone, fluorine, long chain alkyl or fatty acid amide release agent, silica powder or the like.

  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.

[Acid value]
The acid value was measured using an automatic titrator 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 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-propanolic 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.

[Molecular weight]
The molecular weight was measured by using a GPC device manufactured by Tosoh Corporation, HLC-8220 GPC, and obtained as a converted value of polystyrene. The measurement conditions are as follows. Sample concentration: 0.2 wt% (THF solution), sample injection amount: 10 μl, eluent: THF, flow rate: 0.6 ml / min, measurement temperature: 40 ° C., column: sample column; TSKguardcolumn SuperHZ-H1 + TSKgel SuperHZM− H2 lines, reference column; TSKgel SuperH-RC1 line, detector: differential refractometer.

[Glass-transition temperature]
The glass transition temperature Tg (° C.) was determined by the following formula using the following literature values as the glass transition temperature Tgn (° C.) of the homopolymer of each monomer.
Formula: 1 / (Tg + 273) = Σ [Wn / (Tgn + 273)]
[Wherein, Tg (° C.) is the glass transition temperature of the copolymer, Wn (−) is the weight fraction of each monomer, Tgn (° C.) is the glass transition temperature of the homopolymer of each monomer, and n is the type of each monomer Represents. ]
2-ethylhexyl acrylate: -70 ° C
2-hydroxyethyl acrylate: -15 ° C
Isononyl acrylate: -82 ° C
Acrylic acid: 106 ° C.

Production Example 1 (acrylic polymer A)
A mixture of 200 g of 2-ethylhexyl acrylate, 8 g of 2-hydroxyethyl acrylate, 0.4 g of 2,2′-azobisisobutyronitrile and 312 g of ethyl acetate was reacted at 65 ° C. for 6 hours in a nitrogen stream, and Tg = − An acrylic polymer solution (40 wt%) having a temperature of 68 ° C., a weight average molecular weight of 500,000 and an acid value of 0 was obtained.

Production Example 2 (acrylic polymer B)
200 g of isononyl acrylate, 8 g of 2-hydroxyethyl acrylate, 0.4 g of 2,2′-azobisisobutyronitrile and 312 g of ethyl acetate were reacted in a nitrogen stream at 65 ° C. for 6 hours, and Tg = −80 ° C. A solution (40% by weight) of an acrylic polymer having a weight average molecular weight of 540,000 and an acid value of 0 was obtained.

Production Example 3 (Allyl Polymer C)
A mixture of 200 g of 2-ethylhexyl acrylate, 0.1 g of 1-hydroxycyclohexyl phenyl ketone [Irgacure 184 manufactured by Ciba Specialty Chemicals Co., Ltd.] and 0.1 g of benzyldimethyl ketal [Irgacure 651 manufactured by Ciba Specialty Chemicals Co., Ltd.] in a nitrogen stream Then, UV irradiation was performed with a high-pressure mercury lamp to obtain a partial polymer having a polymerization rate of 10% (weight average molecular weight 2.2 million, acid value 0).

Production Example 4 (acrylic polymer D)
A mixture of 200 g of 2-ethylhexyl acrylate, 0.4 g of acrylic acid, 3.6 g of 2-hydroxyethyl acrylate, 0.4 g of 2,2′-azobisisobutyronitrile and 312 g of ethyl acetate in a nitrogen stream at 65 ° C. The mixture was reacted for 6 hours to obtain an acrylic polymer solution (40% by weight) having a Tg of −66 ° C., a weight average molecular weight of 560,000 and an acid value of 1.3.

Production Example 5 (acrylic polymer E)
A mixture of 200 g of 2-ethylhexyl acrylate, 8 g of acrylic acid, 0.4 g of 2,2′-azobisisobutyronitrile and 312 g of ethyl acetate was reacted in a nitrogen stream at 65 ° C. for 6 hours to obtain Tg = −66 ° C. An acrylic polymer solution (40% by weight) having a weight average molecular weight of 540,000 and an acid value of 30 was obtained.

Production Example 6 (Antistatic Agent A)
A mixture of 0.2 g of lithium perchlorate (melting point 236 ° C.) and 9.8 g of polypropylene glycol (diol type, number average molecular weight 2,000) was diluted with 10 g of ethyl acetate to prepare an antistatic agent solution (50% by weight). did.

Production Example 7 (Antistatic film)
10 g of an antistatic agent composed of tin oxide and a polyester resin (manufactured by Solvex Co., Ltd., Microsolver RMd-142) was diluted with a mixed solvent of 30 g of water and 70 g of methanol, and a Meyer bar was formed on a 38 μm thick polyethylene terephthalate film. And an antistatic layer having a thickness of 0.2 μm was formed by heating at 130 ° C. for 1 minute to produce an antistatic film.

Production Example 8 (Antistatic agent B)
10 parts by weight of cationic surfactant lauryltrimethylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd., solid at 25 ° C.) is diluted with 20 parts by weight of ethyl acetate and 20 parts by weight of isopropyl alcohol to obtain an antistatic agent solution (20% by weight). ) Was produced.

Example 1 (Preparation of pressure-sensitive adhesive composition)
The acrylic polymer A solution (40% by weight) obtained in Production Example 1 was diluted to 20% by weight with ethyl acetate, and 1-butyl-3-methylpyridinium trifluoromethanesulfonate (Nippon Carlite) was added to 100 g of this solution as an ionic liquid. 0.1 g of product, product name: BMP-Trf, liquid at 25 ° C., isocyanurate of hexamethylene diisocyanate (Coronate HX manufactured by Nippon Polyurethane Industry Co., Ltd.), dibutyltin dilaurate (1 An acrylic pressure-sensitive adhesive solution was prepared by adding 0.4 g of a weight% ethyl acetate solution).

(Preparation of adhesive sheet)
The acrylic pressure-sensitive adhesive solution was applied to the surface opposite to the antistatic surface of the antistatic film obtained in Production Example 7, and heated at 110 ° C. for 3 minutes to form a pressure-sensitive adhesive layer having a thickness of 20 μm. . Next, a silicone-treated surface of a 25 μm-thick polyethylene terephthalate film with one surface subjected to silicone treatment was bonded to the surface of the pressure-sensitive adhesive layer to prepare a pressure-sensitive adhesive sheet.

Example 2 (Preparation of pressure-sensitive adhesive composition)
N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium bis (trifluoromethanesulfonyl) imide (manufactured by Kanto Chemical Co., Inc., liquid at 25 ° C.) (10 wt% ethyl acetate solution) as an ionic liquid An acrylic pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that 0.5 g was used.

(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 prepared above was used as the acrylic pressure-sensitive adhesive solution.

Example 3 (Preparation of pressure-sensitive adhesive composition)
An acrylic pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the acrylic polymer B solution (40% by weight) obtained in Production Example 2 was diluted to 20% by weight with ethyl acetate and 100 g of this solution was used. did.

(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 prepared above was used as the acrylic pressure-sensitive adhesive solution.

Example 4 (Preparation of pressure-sensitive adhesive composition)
100 g of the partial polymer obtained in Production Example 3 is 0.2 g of 1-butyl-3-methylpyridinium trifluoromethanesulfonate (manufactured by Nippon Carlit Co., Ltd., product name: BMP-Trf, liquid at 25 ° C.) as an ionic liquid, trimethylol An acrylic pressure-sensitive adhesive solution was prepared by adding 1.5 g of propane triacrylate and 0.1 g of benzyldimethyl ketal [Irgacure 651 manufactured by Ciba Specialty Chemicals Co., Ltd.].

(Preparation of adhesive sheet)
The acrylic pressure-sensitive adhesive solution was applied to the surface opposite to the antistatic treatment surface of the antistatic film obtained in Production Example 7 so as to have a thickness of 20 μm, and further treated with a silicone treatment having a thickness of 25 μm. A polyethylene terephthalate film was applied. This sheet was irradiated with ultraviolet rays so as to obtain an illuminance of 37 mW / cm ² and a light amount of 660 mJ / cm ² with a high-pressure mercury lamp, to prepare an adhesive sheet.

Example 5 (Preparation of pressure-sensitive adhesive composition)
Example 1 was used except that 0.5 g of 1-hexyl-3-methylimidazolium trifluoromethanesulfonate (manufactured by ACROS ORGANICS, liquid at 25 ° C.) (10 wt% ethyl acetate solution) was used as the ionic liquid. An acrylic adhesive solution 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 prepared above was used as the acrylic pressure-sensitive adhesive solution.

Example 6 (Preparation of pressure-sensitive adhesive composition)
Example 1 except that 0.1 g of 1-butyl-3-methylpyridinium bis (trifluoromethanesulfonyl) imide (manufactured by Nippon Carlit Co., Ltd., product name: BMP-IL, liquid at 25 ° C.) was used as the ionic liquid. An acrylic pressure-sensitive adhesive solution 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 prepared above was used as the acrylic pressure-sensitive adhesive solution.

Example 7 (Preparation of pressure-sensitive adhesive composition)
A solution (40% by weight) of the acrylic polymer A obtained in Production Example 1 was diluted to 20% by weight with ethyl acetate, and 1-ethyl-3-methylimidazolium (trifluoromethanesulfonyl) as an ionic liquid was added to 100 g of this solution. 0.08 g of trifluoroacetamide (manufactured by Tokuyama, product name: EMI-TSAC, liquid at 25 ° C.), isocyanurate of hexamethylene diisocyanate (Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.), as a crosslinking catalyst An acrylic pressure-sensitive adhesive solution was prepared by adding 0.4 g of dibutyltin dilaurate (1 wt% ethyl acetate solution).

(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 prepared above was used as the acrylic pressure-sensitive adhesive solution.

Example 8 (Preparation of pressure-sensitive adhesive composition)
A solution (40% by weight) of acrylic polymer A obtained in Production Example 1 was diluted to 20% by weight with ethyl acetate, and an aliphatic amine-based ionic liquid (produced by Koei Chemical Co., Ltd. Product name: 0.1 g of IL-A1, liquid at 25 ° C., isocyanurate of hexamethylene diisocyanate (Coronate HX manufactured by Nippon Polyurethane Industry Co., Ltd.), dibutyltin dilaurate (1 wt% acetic acid as a crosslinking catalyst) Ethyl solution) 0.4 g was added to prepare an acrylic adhesive solution.

(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 prepared above was used as the acrylic pressure-sensitive adhesive solution.

Comparative Example 1
An acrylic pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that no ionic liquid was added. A pressure-sensitive adhesive sheet having a thickness of 20 μm was prepared in the same manner as in Example 1 except that this acrylic pressure-sensitive adhesive solution was used as the acrylic pressure-sensitive adhesive solution.

Comparative Example 2
The acrylic pressure-sensitive adhesive solution prepared in Comparative Example 1 was applied to one side of a polyethylene terephthalate film and heated at 110 ° C. for 3 minutes to form a pressure-sensitive adhesive layer having a thickness of 20 μm. Next, the surface of the pressure-sensitive adhesive layer was bonded with a silicone-treated surface of a polyethylene terephthalate film having a thickness of 25 μm, which was subjected to silicone treatment on one surface, to prepare a pressure-sensitive adhesive sheet.

Comparative Example 3
An acrylic pressure-sensitive adhesive solution was prepared in the same manner as in Example 3 except that no ionic liquid was added. A pressure-sensitive adhesive sheet having a thickness of 20 μm was prepared in the same manner as in Example 1 except that this acrylic pressure-sensitive adhesive solution was used as the acrylic pressure-sensitive adhesive solution.

Comparative Example 4
An acrylic pressure-sensitive adhesive solution was prepared in the same manner as in Example 4 except that no ionic liquid was added. A pressure-sensitive adhesive sheet having a thickness of 20 μm was prepared in the same manner as in Example 1 except that this acrylic pressure-sensitive adhesive solution was used as the acrylic pressure-sensitive adhesive solution.

Comparative Example 5
An acrylic pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that the acrylic polymer D solution (40% by weight) obtained in Production Example 4 was diluted to 20% by weight with ethyl acetate and 100 g of this solution was used. did. A pressure-sensitive adhesive sheet having a thickness of 20 μm was prepared in the same manner as in Example 1 except that this acrylic pressure-sensitive adhesive solution was used as the acrylic pressure-sensitive adhesive solution.

Comparative Example 6
The acrylic polymer E solution (40% by weight) obtained in Production Example 5 was diluted to 20% by weight with ethyl acetate, and 1-butyl-3-methylpyridinium trifluoromethanesulfonate (Nippon Carlite) was added as an ionic liquid to 100 g of this solution. 0.2 g of 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd., TETRAD-C). 7 g of trimethylolpropane / tolylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate L) was added to prepare an acrylic pressure-sensitive adhesive solution. A pressure-sensitive adhesive sheet having a thickness of 20 μm was prepared in the same manner as in Example 1 except that this acrylic pressure-sensitive adhesive solution was used.

Comparative Example 7
The acrylic polymer A solution (40% by weight) obtained in Production Example 1 was diluted to 20% by weight with ethyl acetate, and 4.0 g of the antistatic agent solution (50% by weight) of Production Example 6 was added to 100 g of this solution. Add 0.53 g of methylolpropane / tolylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate L), and add 0.4 g of dibutyltin dilaurate (1 wt% ethyl acetate solution) as a crosslinking catalyst. An agent solution was prepared. A pressure-sensitive adhesive sheet having a thickness of 20 μm was prepared in the same manner as in Example 1 except that this acrylic pressure-sensitive adhesive solution was used as the acrylic pressure-sensitive adhesive solution.

Comparative Example 8
In Example 1, an acrylic pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that 0.5 g of the antistatic agent B solution (20% by weight) of Production Example 8 was used instead of the ionic liquid. A pressure-sensitive adhesive sheet having a thickness of 20 μm was prepared in the same manner as in Example 1 except that this acrylic pressure-sensitive adhesive solution was used as the acrylic pressure-sensitive adhesive solution.

Comparative Example 9
The acrylic adhesive solution prepared in Example 2 was applied to one side of a polyethylene terephthalate film and heated at 110 ° C. for 3 minutes to form an adhesive layer having a thickness of 20 μm. Next, a silicone-treated surface of a 25 μm-thick polyethylene terephthalate film with one surface subjected to silicone treatment was bonded to the surface of the pressure-sensitive adhesive layer to prepare a pressure-sensitive adhesive sheet.

Reference example 1
An acrylic pressure-sensitive adhesive solution was prepared in the same manner as in Example 1 except that 8.0 g of 1-butyl-3-methylpyridinium trifluoromethanesulfonate was added as the ionic liquid. A pressure-sensitive adhesive sheet having a thickness of 20 μm was prepared in the same manner as in Example 1 except that this acrylic pressure-sensitive adhesive solution was used as the acrylic pressure-sensitive adhesive solution.

  About the adhesive sheet obtained by said Example, the comparative example, and the reference example, the peeling voltage, the fouling property, and adhesive force were evaluated in the following ways.

[Peeling voltage]
The pressure-sensitive adhesive sheet was cut to a size of 70 mm width and 130 mm length, the separator was peeled off, and then a polarizing plate bonded to an acrylic plate having a thickness of 1 mm, a width of 70 mm and a length of 100 mm that had been previously neutralized [Nitto Denko Corporation ), SEG1425EWVAGS2B, size: width 70 mm, length 100 mm] Press with a hand roller so that one end protrudes 30 mm from the surface. After leaving for one day in an environment of 23 ° C. × 50% RH, a sample is set at a predetermined position as shown in FIG. One end that protrudes 30 mm is fixed to an automatic winder, and is peeled off at a peeling angle of 150 ° and a peeling speed of 10 m / min. The potential of the polarizing plate surface generated at this time was measured with a potential measuring device [KSD-0103 manufactured by Kasuga Electric Co., Ltd.] fixed at a predetermined position. The measurement was performed in an environment of 23 ° C. × 50% RH.

[Contamination]
After the measurement of the above stripping voltage, the peeled adhesive sheet was again attached by hand so that bubbles were mixed between the measured polarizing plate and an evaluation sample was prepared. After leaving for 1 month in an environment of 23 ° C. × 50% RH, the pressure-sensitive adhesive sheet was peeled off from the adherend by hand, and the state of contamination on the adherend surface was visually observed. The evaluation criteria were ○ when no contamination was observed and × when contamination was observed.

[Adhesion measurement]
A 80 μm thick triacetyl cellulose film (Fuji Photo Film Co., Ltd., Fujitac) was cut to a width of 70 mm and a length of 100 mm, immersed in an aqueous solution of sodium hydroxide (10% by weight) at 60 ° C. for 1 minute, and then distilled water. To prepare an adherend. The above adherend was allowed to stand for 1 day in an environment of 23 ° C. × 50% RH, and then used as an adherend for adhesive force evaluation. The pressure-sensitive adhesive sheet cut to a size of 25 mm in width and 80 mm in length was laminated on the adherend for evaluation with a pressure of 0.25 MPa to prepare an evaluation sample. After leaving the laminate for 30 minutes, the adhesive strength when peeled at a peeling speed of 30 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.

  The results are shown in Table 1.

  As is clear from the results of Table 1 above, the pressure-sensitive adhesive sheets of Examples 1 to 8 of the present invention all maintain the adhesive force as compared with the pressure-sensitive adhesive sheets that do not contain the ionic liquid of Comparative Examples 1 to 4. The stripping voltage is suppressed. Moreover, as for the adhesive sheet of Examples 1-8 of this invention, all are not recognized contamination property compared with Comparative Examples 7-9. Therefore, it turns out that the adhesive composition of Examples 1-8 is an adhesive composition excellent in antistatic property and low pollution property.

  In particular, in Comparative Example 8, since a surfactant was used, bleeding occurred. In Comparative Example 7, the effect of preventing bleeding due to complexation of an alkali metal salt was not sufficient.

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

Claims (5)

Ionic liquids, as well as a main component one or more acrylate and / or methacrylate having an alkyl group of 1 to 14 carbon atoms, Ri acid value name contains an acrylic polymer is 1.0 or less,
The acrylic polymer contains 0.5 to 10% by weight of a hydroxyl group-containing monomer in the constituent monomers,
The ionic liquid is a molten salt that exhibits a liquid state at 25 ° C.,
Wherein per 100 parts by weight of the acrylic polymer, pressure-sensitive adhesive composition characterized that you containing 0.01 to 20 parts by weight of the ionic liquid.   The pressure-sensitive adhesive composition according to claim 1, wherein the ionic liquid is at least one of a nitrogen-containing onium salt, a sulfur-containing onium salt, and a phosphorus-containing onium salt. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the ionic liquid contains one or more cations represented by the following general formulas (A) to (D).

[R ₁ in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms and may contain a hetero atom, and R ₂ and R ₃ may be the same or different and each may be hydrogen or 1 to 16 carbon atoms. It represents a hydrocarbon group and may contain a hetero atom. However, when the nitrogen atom contains a double bond, there is no R ₃ . ]
[R ₄ in the formula (B) represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a hetero atom, and R ₅ , R ₆ , and R ₇ may be the same or different and each may represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[R ₈ in Formula (C) represents a hydrocarbon group having 2 to 20 carbon atoms and may contain a hetero atom, and R ₉ , R ₁₀ , and R ₁₁ may be the same or different and each may represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[X in the formula (D) represents a nitrogen, sulfur, or phosphorus atom, and R ₁₂ , R ₁₃ , R ₁₄ , and R ₁₅ are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms. , And may contain a heteroatom. However, when X is a sulfur atom, there is no R12. ]   A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition according to claim 1 on one side or both sides of a support.   The pressure-sensitive adhesive sheet according to claim 4, wherein the support comprises a plastic film that has been subjected to antistatic treatment.

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