JP2011116993A - Pressure-sensitive adhesive composition, tacky sheets, and surface protective film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pressure-sensitive adhesive composition which attempts to prevent the electrification on an adherend without antistatic treatment, at the time of peeling, and reduces the pollution on the adherend and which is excellent in the adhesion reliability; as well as antistatic tacky sheets using the same; and a surface protective film. <P>SOLUTION: This pressure-sensitive adhesive composition contains a toluene-soluble ionic liquid and a polymer of the base polymer with a glass transition temperature Tg of 0°C or lower. <P>COPYRIGHT: (C)2011,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 formed into a sheet form or a tape form using the same.

The pressure-sensitive adhesive sheets comprising the antistatic pressure-sensitive adhesive composition of the present invention are suitably used for plastic products and the like that are likely to generate static electricity. In particular, it is useful as an antistatic pressure-sensitive adhesive sheet and a surface protective film used in applications that dislike static electricity such as electronic devices.

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

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

To date, as an attempt to suppress the above-described electrostatic charge, for example, there is a method of adding a low molecular surfactant to an adhesive and transferring the surfactant from the adhesive to an adherend to prevent charging. It is disclosed (for example, see Patent Document 1). However, these low molecular surfactants are likely to bleed on the surface of the pressure-sensitive adhesive, and when applied to a protective film, there is a concern about contamination of the adherend. Therefore, when a pressure-sensitive adhesive to which a low molecular surfactant is added is applied to the protective film for an optical member, it is difficult to develop sufficient antistatic properties without impairing the optical properties of the optical member.

Further, a method is disclosed in which an antistatic agent comprising a polyether polyol and an alkali metal salt is added to an acrylic pressure-sensitive adhesive to suppress bleeding of the antistatic agent on the surface of the pressure-sensitive adhesive (for example, see Patent Document 2). . However, even in this method, bleeding of the antistatic agent is unavoidable, and as a result, when applied to a surface protective film, if the treatment is performed over time or under high temperature, the adherend is contaminated by the bleeding phenomenon. It turns out that it occurs.

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

Therefore, in order to solve the problems in the conventional antistatic pressure-sensitive adhesive sheets, the present invention can prevent the adherend that is not antistatic when peeled off and reduce the contamination of the adherend. An object of the present invention is to provide a pressure-sensitive adhesive composition having excellent adhesion reliability, an antistatic pressure-sensitive adhesive sheet using the same, and a surface protective film.

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

That is, the pressure-sensitive adhesive composition of the present invention is characterized by containing a toluene-soluble ionic liquid and a polymer having a glass transition temperature Tg of 0 ° C. or less as a base polymer.

According to the pressure-sensitive adhesive composition of the present invention, as shown in the results of the examples, since the toluene-soluble ionic liquid and a polymer having a glass transition temperature Tg of 0 ° C. or less as a base polymer are contained, they are crosslinked. The pressure-sensitive adhesive layer is excellent in antistatic properties and pressure-sensitive adhesive properties when peeled, with less contamination to the object to be protected. Although the details of the reason why such characteristics are exhibited by using the above-described toluene-soluble ionic liquid are not clear, the toluene-soluble ionic liquid is compatible with a polymer having a glass transition temperature Tg of 0 ° C. or lower, and ion conductivity. It is presumed that it contributes to a well-balanced interaction, and thus enables good adhesion properties, charging properties, and suppression of contamination.

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

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

In addition, since the above ionic liquid is preferably in a liquid state near room temperature, it can be easily added to, dispersed in, 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 present invention is characterized by containing a toluene-soluble ionic liquid. Toluene-soluble means being soluble in toluene, and more specifically refers to the property that the ionic liquid is uniformly dissolved in toluene when a 10 wt% toluene solution of the ionic liquid is prepared. By using such a toluene-soluble ionic liquid, the antistatic property is further improved. The reason why the antistatic property is improved by using the toluene-soluble ionic liquid is not clear, but it is presumed that the difference in polarity of the ionic liquid favorably contributes to the antistatic property.

More specifically, since ionic liquids generally have high polarity, they have poor wettability with nonpolar materials such as silicone and fluorine, while toluene-soluble ionic liquids, which are nonpolar solvents, are ionic. Since the polarity is low among liquids, it is estimated that wettability to nonpolar materials such as silicone and fluorine is improved, and excellent antistatic ability can be obtained even for nonpolar adherends. .

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.

[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 1 to 16 carbon atoms. 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 may be the same or different, It represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
_{[R h} in the formula (C) represents a hydrocarbon group having from 2 to 20 carbon atoms, and may contain a hetero _atom, R i, _{R j,} and _{R k} are the same or different, hydrogen or carbon atoms It 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 . ]

Further, in the present invention, the ionic liquid _CF 3 SO ₃ ^- preferably comprises an anion. CF ₃ SO ₃ ^- by using an ionic liquid comprising an anion, easily obtain an ionic liquid having improved solubility in toluene (toluene soluble).

Moreover, in this invention, it becomes an adhesive composition which was further excellent in antistatic property by using together an ether group containing compound. The reason why the antistatic property is improved by combining the ether group-containing compound is not clear, but the combined use of the ether group-containing compound improves the wettability with respect to non-polar materials such as fluorine and is ionic. Transfer of the liquid onto the adherend can be performed efficiently.

Further, the polymer having a glass transition temperature Tg of 0 ° C. or lower is preferably a (meth) acrylic polymer having as a main component at least one (meth) acrylate having an alkyl group having 1 to 14 carbon atoms. These (meth) acrylic polymers provide a good balance of compatibility with the ionic liquid and the base polymer, and can sufficiently maintain the adhesive properties.

The (meth) acrylic polymer in the present invention refers to an acrylic polymer and / or a methacrylic polymer. Further, (meth) acrylate refers to acrylate and / or methacrylate.

On the other hand, the pressure-sensitive adhesive layer of the present invention is obtained by crosslinking the pressure-sensitive adhesive composition described above. By appropriately adjusting the structural unit, the structural ratio, the selection of the crosslinking agent and the addition ratio of the polymer having a glass transition temperature Tg of 0 ° C. or lower, and the like, it is possible to obtain pressure-sensitive adhesive sheets having more excellent heat resistance. .

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

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. According to the surface protective film of the present invention, since the pressure-sensitive adhesive composition obtained by crosslinking the pressure-sensitive adhesive composition having the above-described effects is provided, it is possible to prevent static charge on an adherend that is not antistatic when peeled off. Thus, the pressure-sensitive adhesive sheets are excellent in adhesion reliability with reduced contamination of the adherend. For this reason, in particular, it becomes very useful as an antistatic surface protective film in a technical field related to electronic equipment, in which electrostatic charging and contamination are particularly serious problems.

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

The pressure-sensitive adhesive composition of the present invention is characterized by containing a toluene-soluble ionic liquid and a polymer having a glass transition temperature Tg of 0 ° C. or lower as a base polymer.

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

As the ionic liquid, a nitrogen-containing onium salt, a sulfur-containing onium salt, or a phosphorus-containing onium salt is preferably used, and is represented by the following general formulas (A) to (D) for the reason that particularly excellent antistatic ability is obtained. What consists of an organic cation component and a fluorine-containing 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 1 to 16 carbon atoms. 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 may be the same or different, It represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
_{[R h} in the formula (C) represents a hydrocarbon group having from 2 to 20 carbon atoms, and may contain a hetero _atom, R i, _{R j,} and _{R k} are the same or different, hydrogen or carbon atoms It represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[Z in Formula (D) represents a nitrogen, sulfur, or phosphorus atom, and R ₁ , R _m , R _n , and R _o are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms. And may contain heteroatoms. However, when Z is a sulfur atom, there is no _Ro . ]

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

Specific examples include, for example, 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-hexyl. -3-methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1,1-dimethylpyrrolidinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidi Examples thereof include a nium cation, a 2-methyl-1-pyrroline cation, a 1-ethyl-2-phenylindole cation, a 1,2-dimethylindole cation, and a 1-ethylcarbazole cation.

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

Specific examples include, for example, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, and 1-helium. Xyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazole Cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation, 1-butyl-2,3-dimethylimidazolium cation, 1-hexyl-2,3 -Dimethylimidazolium cation, 1,3-dimethyl -1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,4-tetramethyl-1, 4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidi Cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3-trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydro Pyrimidinium cation, 1,2,3,4-tetramethyl-1,4-dihydropyrimidinium cation, 1,2,3,4-tetramethyl-1,6-dihydropyrimidini Such as Mukachion, and the like.

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

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

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

Specific examples include, for example, tetramethylammonium cation, tetraethylammonium cation, tetrapropylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, tetraheptylammonium cation, triethylmethylammonium cation, tributylethylammonium Cation, trimethyldecyl ammonium cation, trioctylmethyl ammonium cation, tripentyl butyl ammonium cation, trihexyl methyl ammonium cation, trihexyl pentyl ammonium cation, triheptyl methyl ammonium cation, tripentyl butyl ammonium cation, triheptyl hexyl ammonium cation Dimethyldihexylammonium cation, dipropyldihexylammonium cation, heptyldimethylhexylammonium cation, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, diallyldimethylammonium cation, N , N-dimethyl-N, N-dipropylammonium cation, N, N-dimethyl-N, N-dihexylammonium cation, N, N-dipropyl-N, N-dihexylammonium cation, N, N-dimethyl-N- Ethyl-N-propylammonium cation, N, N-dimethyl-N-ethyl-N-butylammonium cation, N, N-dimethyl-N-ethyl-N-pentylammonium cation, N, N-di Tyl-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, trimethylheptylammonium cation Thione, 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, 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-pentylan Nium cation, N, N-dibutyl-N-methyl-N-hexylammonium cation, trioctylmethylammonium cation, N-methyl-N-ethyl-N-propyl-N-pentylammonium cation, trimethylsulfonium cation, triethylsulfonium cation , Tributylsulfonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrapentylphosphonium cation, tetrahexylphosphonium cation, tetrahexyl Heptylphosphonium cation, tetraoctylphosphoniu Cation, triethyl methyl phosphonium cation, tributyl ethyl phosphonium cation, trimethyl decyl phosphonium cation, such as diallyl dimethyl ammonium cation.

Among them, tetramethylammonium cation, tetraethylammonium cation, tetrapropylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, tetraheptylammonium cation, triethylmethylammonium cation, tributylethylammonium cation, trimethyldecyl Ammonium cation, Trioctylmethylammonium cation, Tripentylbutylammonium cation, Trihexylmethylammonium cation, Trihexylpentylammonium cation, Triheptylmethylammonium cation, Tripentylbutylammonium cation, Triheptylhexylammonium cation, Dimethyldihexene Silammonium cation, dipropyldihexylammonium cation, heptyldimethylhexylammonium cation, N, N-diethyl-N-methyl-N- (2-methoxyethyl) ammonium cation, glycidyltrimethylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, Tributylsulfonium cation, trihexylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, dimethyldecylsulfonium cation, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrabutylphosphonium cation, tetrapentylphosphonium cation, tetrahexylphosphonium cation, tetraheptyl Hos Cation, tetra octyl phosphonium cation, triethyl methyl phosphonium cation, tributyl ethyl phosphonium cation, tributyl ethyl phosphonium cation, trimethyl decyl phosphonium cation, such as diallyl dimethyl ammonium cation is preferably used.

On the other hand, the anion component is not particularly limited as long as it satisfies that it becomes a toluene-soluble ionic liquid. For example, Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF _{4 are used. ^{-, 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 - are used. Among them, CF ₃ SO ₃ ^- anion, to become easier to obtain an ionic liquid having improved solubility in toluene (toluene soluble), preferably used.

In the present invention, a toluene-soluble ionic liquid is used. The toluene-soluble ionic liquid can be obtained by appropriately combining the cation component and the anion component. 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. These cationic components and anionic components may be used alone or in combination of two or more.

Specific examples of the toluene-soluble ionic liquid include, for example, tetrapentylammonium trifluoromethanesulfonate, tetrahexylammonium trifluoromethanesulfonate, tetraheptylammonium 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 for synthesizing the ionic liquid is not particularly limited as long as the target ionic liquid is obtained. In general, the document “ionic liquids—the forefront and future of development” [CMC Publishing Co., Ltd.] A halide method, a hydroxide method, an acid ester method, a complex formation method, a neutralization method and the like as described in “Issuance” are used.

The synthesis method of the halide method, hydroxide method, acid ester method, complex formation method, and neutralization method will be described below using a nitrogen-containing onium salt as an example. Other sulfur-containing onium salts, phosphorus-containing onium salts, etc. This ionic liquid can also be obtained by the same method.

The halide method is a method carried out by reactions as shown in the following formulas (1) to (3). First, a tertiary amine and an alkyl halide are reacted to obtain a halide (reaction formula (1), and chlorine, bromine, and iodine are used as the halogen).

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

The hydroxide method is a method performed by reactions as shown in (4) to (8). First, halide (R ₄ NX) is subjected to ion exchange membrane electrolysis (reaction formula (4)), OH type ion exchange resin method (reaction formula (5)) or reaction with silver oxide (Ag ₂ O) (reaction formula ( 6)) to obtain a hydroxide (R ₄ NOH) (chlorine, bromine and iodine are used as the halogen).

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

The acid ester method is a method performed by reactions as shown in (9) to (11). First, a tertiary amine (R ₃ N) is reacted with an acid ester to obtain an acid ester product (Reaction Formula (9)). As the acid ester, inorganic acids such as sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid, and carbonic acid are used. 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 with a fluoride such as BF ₃ , AlF ₃ , PF ₅ , ASF ₅ , SbF ₅ , NbF ₅ , TaF ₅ (reaction) Formula (15)).

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

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

Said ionic liquid may be used independently and may be used in mixture of 2 or more types.

The blending amount of the ionic liquid cannot be defined unconditionally because it varies depending on the compatibility of the (meth) acrylic polymer to be used and the ionic liquid, but is generally 0 with respect to 100 parts by weight of the base polymer. 0.01 to 40 parts by weight is preferable, 0.03 to 20 parts by weight is more preferable, and 0.05 to 10 parts by weight is most preferable. If it is less than 0.01 part by weight, sufficient antistatic properties cannot be obtained, and if it exceeds 40 parts by weight, the contamination of the adherend tends to increase.

In the present invention, a polymer having a glass transition temperature Tg of 0 ° C. or lower is used as the base polymer, preferably Tg is −100 to −5 ° C., more preferably Tg is −80 to −10 ° C. When the glass transition temperature Tg exceeds 0 ° C., it is difficult to obtain a sufficient adhesive force even when an ionic liquid is contained.

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

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

The (meth) acrylic polymer having one or more of (meth) acrylates having an alkyl group having 1 to 14 carbon atoms as a main component has an alkyl group having 1 to 14 carbon atoms (meth) ) A (meth) acrylic polymer 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 acrylates. In addition, a weight average molecular weight means what was obtained by measuring by GPC (gel permeation chromatography).

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

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

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

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

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

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) In this case, acrylic acid is adjusted to 3.7 parts by weight or less with respect to 100 parts by weight of the total amount of 2-ethylhexyl acrylate and acrylic acid, thereby satisfying the above acid value. I can do it.

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

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

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

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

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

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

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

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

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

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

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

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

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

The other polymerizable monomer components described above may be used alone or in admixture of two or more, but the total content is the total structural unit of the (meth) acrylic polymer The polymerizable monomer component is preferably 0 to 49 parts by weight, more preferably 0.1 to 45 parts by weight, and particularly preferably 3 to 35 parts by weight with respect to 100 parts by weight. . By using the other polymerizable monomer components described above, good interaction with the ionic liquid and good adhesiveness can be appropriately adjusted.

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

The pressure-sensitive adhesive composition of the present invention can appropriately contain an ether group-containing compound. By including the ether group-containing compound in the pressure-sensitive adhesive composition, the pressure-sensitive adhesive composition is further excellent in antistatic properties.

The ether group-containing compound in the present invention is not particularly limited as long as it is a compound having an ether group, and a known ether group-containing compound is used.

Specific examples of the ether group-containing compound include polyether polyol compounds and alkylene oxide group-containing compounds.

Examples of the polyether polyol compound include polyethylene glycol (diol type), polypropylene glycol (triol type), polytetramethylene ether glycol, and the above derivatives and block copolymers of polypropylene glycol polypropylene glycol-polyethylene glycol-polypropylene glycol, polypropylene. Random copolymer and block copolymer of polyethylene glycol and polypropylene glycol such as block copolymer of glycol-polyethylene glycol, block copolymer of polyethylene glycol-polypropylene glycol-polyethylene glycol, and random copolymer of polypropylene glycol-polyethylene glycol Coalesce.

In addition, the end of the glycol chain may be a hydroxyl group, or may be substituted with an alkyl group, a phenyl group, or the like.

Examples of the alkylene oxide group-containing compound include polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene diamine, polyoxypropylene diamine, alkylene glycol group-containing (meth) acrylic polymer, alkylene oxide group-containing polyether polymer. , Alkylene oxide group-containing polyether ester amide, alkylene oxide group-containing polyether amide imide, polyoxyethylene glycol fatty acid ester, polyoxypropylene glycol fatty acid ester, polyoxysorbitan acid fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxypropylene Alkyl phenyl ether, polyoxyethylene alkyl ether, polyoxypropylene alkyl ether Le, polyoxyethylene alkyl allyl ether, polyoxypropylene alkyl allyl ether.

Among them, polyether polyol compounds, alkylene glycol group-containing (meth) acrylates, and polyoxyethylene alkyl phenyl ethers, polyoxypropylene alkyl phenyl ethers, polyoxyethylene alkyl ethers, polyoxypropylene alkyl ethers, polyoxyethylene alkyls Ether type surfactants such as allyl ether and polyoxypropylene alkyl allyl ether are preferably used because they are easily balanced in compatibility with the base polymer.

Examples of the oxyalkylene unit to (meth) acrylate include those having an alkylene group having 1 to 6 carbon atoms, such as an oxymethylene group, an oxyethylene group, an oxypropylene group, and an oxybutylene group.

Moreover, as addition mole number of the oxyalkylene unit to (meth) acrylate, 1-30 are preferable from a viewpoint that an ionic liquid coordinates, and 2-20 are more preferable.

In addition, the terminal of the oxyalkylene chain may be substituted with a hydroxyl group, an alkyl group, a phenyl group, or the like.

Examples of the alkylene glycol group-containing (meth) acrylate include methoxypolyethylene glycol (meth) acrylate types such as methoxydiethylene glycol (meth) acrylate and methoxytriethylene glycol (meth) acrylate, ethoxy-diethylene glycol (meth) acrylate, and ethoxy-tri Ethoxy-polyethylene glycol (meth) acrylate type such as ethylene glycol (meth) acrylate, butoxy-polyethylene glycol (meth) acrylate type such as butoxy-diethylene glycol (meth) acrylate, butoxy-triethylene glycol (meth) acrylate, phenoxy-diethylene glycol (Meth) acrylate, phenoxy-triethylene glycol (meth) acrylate Which phenoxy-polyethylene glycol (meth) acrylate type, methoxypolypropylene glycol (meth) acrylate type such as methoxydipropylene glycol (meth) acrylate, 2-ethylhexyl-polyethylene glycol (meth) acrylate, nonylphenol-polyethylene glycol (meth) acrylate, etc. Can be given.

In addition to the above components, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (Meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl Using an acrylate and / or methacrylate having an alkyl group having 1 to 14 carbon atoms such as (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate and the like. It is also possible.

Furthermore, carboxyl group-containing (meth) acrylate, sulfonic acid group-containing (meth) acrylate, phosphoric acid group-containing (meth) acrylate, cyano group-containing (meth) acrylate, vinyl esters, aromatic vinyl compounds, acid anhydride groups Containing (meth) acrylate, hydroxyl group-containing (meth) acrylate, amide group-containing (meth) acrylate, amino group-containing (meth) acrylate, imide group-containing (meth) acrylate, epoxy group-containing (meth) acrylate, N-acryloylmorpholine Vinyl ethers can also be used as appropriate.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Moreover, you may use an ether type surfactant as an ether group containing compound in this invention. Specific examples of the ether type surfactant include, for example, ADEKA rear soap NE-10, ADEKA rear soap SE-20N, ADEKA rear soap ER-10, ADEKA rear soap SR-10N, ADEKA rear soap SR-20N (above, Asahi Denka Co., Ltd.), Emulgen 120 (Kao Corporation), Neugen EA130T (Daiichi Kogyo Seiyaku Co., Ltd.) and the like.

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

The ether group-containing compound may be used alone or in combination, but the blending amount is preferably 0.01 to 40 parts by weight with respect to 100 parts by weight of the base polymer, More preferably, it is 0.1 to 20 parts by weight. If the amount is less than 0.01 parts by weight, sufficient charging characteristics cannot be obtained, and if it exceeds 40 parts by weight, bleeding to the adherend tends to increase and the adhesive strength tends to decrease, such being undesirable.

In the pressure-sensitive adhesive composition of the present invention, pressure-sensitive adhesive sheets having further excellent heat resistance can be obtained by appropriately crosslinking a base polymer, particularly a (meth) acrylic polymer. Specific means of the crosslinking method include, for example, a carboxyl group, a hydroxyl group, an amino group, an amide group, and the like that are appropriately included as a crosslinking base point in a (meth) acrylic polymer such as an isocyanate compound, an epoxy compound, a melamine resin, or an aziridine compound. There is a method using a so-called crosslinking agent in which a compound having a reactive group is added and reacted. Among these, an isocyanate compound and an epoxy compound are particularly preferably used mainly from the viewpoint of obtaining an appropriate cohesive force. These compounds may be used alone or in combination of two or more.

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

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

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

Examples of the melamine resin include hexamethylol melamine.

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

The amount of these crosslinking agents to be used is appropriately selected depending on the balance with the (meth) acrylic polymer to be crosslinked, and further depending on the intended use as the pressure-sensitive adhesive sheet. In general, in order to obtain sufficient heat resistance by the cohesive force of the acrylic pressure-sensitive adhesive, it is preferably 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 part by weight, the crosslinking formation by the crosslinking agent is insufficient, the cohesive force of the pressure-sensitive adhesive composition is reduced, and sufficient heat resistance may not be obtained. There is a tendency to cause the rest. On the other hand, when the content exceeds 15 parts by weight, the cohesive force of the polymer is large, the fluidity is lowered, the wettability to the adherend is insufficient, and it tends to cause peeling.

Further, it can be added as a polyfunctional monomer having two or more radiation-reactive unsaturated bonds as a substantial cross-linking agent, and cross-linked by radiation or the like.

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

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

The amount of the polyfunctional monomer used is appropriately selected depending on the balance with the (meth) 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 0.1 to 30 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer. From the viewpoint of flexibility and adhesiveness, it is more preferable to add 10 parts by weight or less with respect to 100 parts by weight of the (meth) acrylic polymer.

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

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

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

Examples of the cationic photopolymerization initiator include onium salts such as aromatic diazonium salts, aromatic iodonium salts, and aromatic sulfonium salts, and organometallic complexes such as iron-allene complexes, titanocene complexes, and arylsilanol-aluminum complexes, Examples thereof include nitrobenzyl ester, sulfonic acid derivative, phosphoric acid ester, phenol sulfonic acid ester, diazonaphthoquinone, and N-hydroxyimide sulfonate. About the said photoinitiator, it is also possible to use 2 or more types together.

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

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

On the other hand, the pressure-sensitive adhesive layer of the present invention is obtained by crosslinking the pressure-sensitive adhesive composition as described above. The pressure-sensitive adhesive sheets of the present invention are formed by forming such a pressure-sensitive adhesive layer on a support film. At that time, the pressure-sensitive adhesive composition is generally crosslinked after application of the pressure-sensitive adhesive composition, but the pressure-sensitive adhesive layer comprising the crosslinked pressure-sensitive adhesive composition can be transferred to a support film or the like. is there.

In the case where a photopolymerization initiator as an optional component is added as described above, the pressure-sensitive adhesive composition is applied directly on the object to be protected, or after being applied to one or both sides of the support substrate, An adhesive layer can be obtained by light irradiation. Usually, the pressure-sensitive adhesive layer is obtained by irradiating ultraviolet rays having an illuminance of 1 to 200 mW / cm ² at a wavelength of 300 to 400 nm and photopolymerizing them with a light amount of about 200 to 4000 mJ / cm ² .

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

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

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

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

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

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

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

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

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

Examples of the antistatic agent contained in the antistatic resin include cationic antistatic agents having cationic functional groups such as quaternary ammonium salts, pyridinium salts, primary, secondary and tertiary amino groups, and sulfones. Anionic antistatic agents with anionic functional groups such as acid salts, sulfate esters, phosphonates, phosphate esters, alkylbetaines and derivatives thereof, imidazolines and derivatives thereof, and amphoteric antistatic agents such as alanine and derivatives thereof Nonionic antistatic agents such as agents, amino alcohols and derivatives thereof, glycerin and derivatives thereof, polyethylene glycol and derivatives thereof, and monomers having ion conductive groups of the above cation type, anion type and zwitterionic type Examples thereof include ionic conductive polymers obtained by polymerization or copolymerization. These compounds may be used alone or in combination of two or more.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

In the pressure-sensitive adhesive sheets of the present invention, a separator can be bonded to the pressure-sensitive adhesive surface for the purpose of protecting the pressure-sensitive adhesive surface as necessary. As a base material constituting the separator, there are paper and plastic film, but a plastic film is preferably used from the viewpoint of excellent surface smoothness.

The film is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. For example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer Examples thereof include a coalesced film, a polyethylene terephthalate film, a polybutylene terephthalate film, a polyurethane film, and an ethylene-vinyl acetate copolymer film.

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

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

<Evaluation of toluene solubility>
9 parts by weight of toluene (manufactured by Wako Pure Chemical Industries, Ltd., special grade) was added to 1 part by weight of the ionic liquid, mixed and stirred at room temperature (25 ° C.) for 10 minutes, and then allowed to stand for 30 minutes.

Then, the solubility was visually evaluated to determine toluene solubility. The evaluation criterion was “soluble” (toluene soluble) when no separated product was observed and dissolved uniformly.

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

A = {(Y−X) × f × 5.611} / M
A: Acid number Y: Titration volume of sample solution (ml)
X: Titration volume of a solution containing only 50 g of mixed solvent (ml)
f; Factor M of the titration solution; 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 prepare a sample solution.

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

<Measurement of molecular weight>
The molecular weight was measured using a GPC apparatus (HLC-8220GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.

Sample concentration: 0.2 wt% (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow rate: 0.6 ml / min
Measurement temperature: 40 ° C
column:
Sample column;
TSK guard column Super HZ-H (1) + TSK gel super HZM-H (2)
Reference column;
TSKgel SuperH-RC (1 pc.)
Detector: Differential refractometer (RI)
The molecular weight was determined in terms of polystyrene.

<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
Isononyl acrylate: -82 ° C
2-hydroxyethyl acrylate: -15 ° C
Acrylic acid: 106 ° C
For literature values, refer to the description of “Synthesis / design of acrylic resin and development of new applications” (published by Chubu Business Development Center Publishing Department).

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

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

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

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

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

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

<Measurement of peeling voltage>
The pressure-sensitive adhesive sheet is cut to a size of 70 mm in width and 130 mm in length, the separator is peeled off, and then a polarizing plate bonded to an acrylic plate (thickness: 1 mm, width: 70 mm, length: 100 mm) previously neutralized. Nitto Denko Co., Ltd., SEG1224DUARC150T, width: 70 mm, length: 100 mm) The surface was crimped with a hand roller so that one end protruded 30 mm.

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

<Evaluation of contamination>
The pressure-sensitive adhesive sheet was cut into a size of 70 mm in width and 100 mm in length and subjected to surface treatment with a fluorine compound (Nitto Denko Corp., SEG1424 DURACT150T, width: 70 mm, length: 100 mm), the pressure-sensitive adhesive sheet and the polarizing plate In the state where air bubbles were mixed between the two, they were bonded together by hand to prepare an evaluation sample.

This evaluation sample is left in an environment of 50 ° C. × 92% RH for 24 hours, then left in an environment of 23 ° C. × 50% RH for 2 hours, and then the adhesive sheet is peeled off from the adherend by hand. The contamination state of the adherend surface was visually observed. The evaluation criteria are as follows.

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

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

After the adherend was allowed to stand in an environment of 23 ° C. × 50% RH for 24 hours, an adhesive sheet cut to a width of 25 mm and a length of 100 mm was laminated to the adherend at a pressure of 0.25 MPa, and an evaluation sample was prepared. Produced.

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

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

(Acrylic polymer (B))
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube and a condenser, 200 parts by weight of isononyl acrylate, 8 parts by weight of 2-hydroxyethyl acrylate, and 2,2′-azobisiso as a polymerization initiator Charge 0.4% by weight of butyronitrile and 312 parts by weight of ethyl acetate, introduce nitrogen gas with gentle stirring, and perform a polymerization reaction for 6 hours while maintaining the liquid temperature in the flask at around 65 ° C. A polymer (B) solution (40% by weight) was prepared. This acrylic polymer (B) had Tg = −80 ° C., a weight average molecular weight of 540,000, and an acid value of 0.0.

<Preparation of ionic liquid>
(Ionic liquid (1))
To a four-necked flask equipped with a stirring blade, a thermometer, and a condenser, 10 parts by weight of tetra-n-pentylammonium bromide (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added. A 50 wt% aqueous solution of 5 parts by weight of trifluoromethanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) was gradually added. After the addition, stirring was continued at 23 ° C. for 2 hours, and then allowed to stand for 12 hours. After removing the supernatant, it was dried in an environment of 110 ° C. for 2 hours to obtain 6.5 parts by weight of an ionic liquid (1) which was liquid at 23 ° C.

The obtained ionic liquid (1) was subjected to NMR ( ¹ H, ¹³ C) measurement, FT-IR measurement, and XRF measurement to identify and confirm that it was tetra-n-pentylammonium trifluoromethanesulfonate. Moreover, toluene solubility was evaluated and it confirmed having toluene solubility.

(Ionic liquid (2))
To a four-necked flask equipped with a stirring blade, a thermometer, and a condenser, 10 parts by weight of tetra-n-hexylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) is added, and then 40 parts by weight of distilled water and 50 parts by weight of dichloromethane are added. After the addition, 4 parts by weight of 50% by weight aqueous solution of lithium trifluoromethanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) was gradually added while turning the stirring blade. After the addition, stirring was continued at 23 ° C. for 2 hours, and then allowed to stand for 12 hours. Next, the supernatant was removed to obtain a dichloromethane solution.

The obtained dichloromethane solution was washed twice with 100 parts by weight of distilled water, and the dichloromethane was extracted and removed, followed by drying in an environment of 110 ° C. for 2 hours to obtain a liquid ionic liquid (2) at 23 ° C. 10 parts by weight were obtained.

The obtained ionic liquid (2) was subjected to NMR ( ¹ H, ¹³ C) measurement, FT-IR measurement, and XRF measurement to identify and confirm that it was tetra-n-hexylammonium trifluoromethanesulfonate. Moreover, toluene solubility was evaluated and it confirmed having toluene solubility.

(Ionic liquid (3))
10 parts by weight of tetra-n-heptylammonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) is added to a four-necked flask equipped with a stirring blade, a thermometer and a condenser, and then 70 parts by weight of distilled water and 50 parts by weight of dichloromethane are added. After the addition, 4 parts by weight of 50% by weight aqueous solution of lithium trifluoromethanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) was gradually added while turning the stirring blade. After the addition, stirring was continued at 23 ° C. for 2 hours, and then allowed to stand for 12 hours. Next, the supernatant was removed to obtain a dichloromethane solution.

The obtained dichloromethane solution was washed twice with 100 parts by weight of distilled water, and dichloromethane was extracted and removed, followed by drying in an environment of 110 ° C. for 2 hours to obtain a liquid ionic liquid (3) at 23 ° C. 11 parts by weight were obtained.

The obtained ionic liquid (3) was subjected to NMR ( ¹ H, ¹³ C) measurement, FT-IR measurement, and XRF measurement to identify and confirm that it was tetra-n-heptylammonium trifluoromethanesulfonate. Moreover, toluene solubility was evaluated and it confirmed having toluene solubility.

(Ionic liquid (4))
10 parts by weight of tetra-n-octylphosphonium bromide (manufactured by Tokyo Chemical Industry Co., Ltd.) is added to a four-necked flask equipped with a stirring blade, a thermometer and a condenser, and then 200 parts by weight of distilled water and 50 parts by weight of dichloromethane are added. After the addition, a 50 wt% aqueous solution of 3 parts by weight of lithium trifluoromethanesulfonate (manufactured by Tokyo Chemical Industry Co., Ltd.) was gradually added while rotating the stirring blade. After the addition, stirring was continued at 23 ° C. for 2 hours, and then allowed to stand for 12 hours. Next, the supernatant was removed to obtain a dichloromethane solution.

The obtained dichloromethane solution was washed twice with 100 parts by weight of distilled water, and the dichloromethane was extracted and removed, followed by drying in an environment of 110 ° C. for 2 hours to obtain a liquid ionic liquid (4) at 23 ° C. 10 parts by weight were obtained.

The obtained ionic liquid (4) was subjected to NMR ( ¹ H, ¹³ C) measurement, FT-IR measurement, and XRF measurement to identify and confirm that it was tetra-n-octylphosphonium trifluoromethanesulfonate. Moreover, toluene solubility was evaluated and it confirmed having toluene solubility.

(Ionic liquid (5))
To a four-necked flask equipped with a stirring blade, a thermometer, and a condenser, 10 parts by weight of tetra-n-pentylammonium bromide (manufactured by Tokyo Kasei Kogyo Co., Ltd.) was added. 9 parts by weight of bis (trifluoromethanesulfone) imide (manufactured by Kishida Chemical Co., Ltd.) was added gradually. After the addition, stirring was continued at 23 ° C. for 1 hour, and then 70 parts by weight of dichloromethane was added. After further stirring for 1 hour, the mixture was allowed to stand for 12 hours. Next, the supernatant was removed to obtain a dichloromethane solution.

The obtained dichloromethane solution was washed with 100 parts by weight of distilled water three times, and dichloromethane was extracted and removed, followed by drying in an environment of 110 ° C. for 2 hours to obtain a liquid ionic liquid (5) at 23 ° C. 15 parts by weight were obtained.

The obtained ionic liquid (5) is subjected to NMR ( ¹ H, ¹³ C) measurement, FT-IR measurement, and XRF measurement to identify and confirm that it is tetra-n-pentylammonium bis (trifluoromethanesulfone) imide. did. Moreover, toluene solubility was evaluated and it confirmed that it did not have toluene solubility.

(Ionic liquid (6))
After adding a 20 wt% aqueous solution of 10 parts by weight of 1-butyl-3-methylpyridinium claloid (manufactured by Wako Pure Chemical Industries, Ltd.) to a four-necked flask equipped with a stirring blade, a thermometer, and a condenser, a stirring blade , 19 parts by weight of a 20% by weight aqueous solution of lithium bis (trifluoromethanesulfone) imide (manufactured by Kishida Chemical Co., Ltd.) was gradually added. After the addition, stirring was continued at 23 ° C. for 2 hours, and then allowed to stand for 12 hours. Next, the supernatant liquid was removed to obtain a liquid product.

The obtained liquid product was washed three times with 100 parts by weight of distilled water and then dried in an environment of 110 ° C. for 2 hours to obtain 20 parts by weight of an ionic liquid (6) which was liquid at 23 ° C. It was.

The obtained ionic liquid (6) is subjected to NMR ( ¹ H, ¹³ C) measurement, FT-IR measurement, and XRF measurement, and is identified as 1-butyl-3-methylpyridinium bis (trifluoromethanesulfone) imide. ·confirmed. Moreover, toluene solubility was evaluated and it confirmed that it did not have toluene solubility.

<Preparation of antistatic agent solution>
(Antistatic agent solution (a))
In a four-necked flask equipped with a stirring blade, a thermometer, and a condenser, 0.1 part by weight of lithium perchlorate, 9.9 parts by weight of polypropylene glycol (diol type, number average molecular weight: 2000), 10 parts by weight of ethyl acetate The mixture was stirred for 2 hours while maintaining the liquid temperature in the flask at around 80 ° C. to prepare an antistatic agent solution (a) (50 wt%).

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

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

[Example 1]
(Preparation of adhesive composition)
The acrylic polymer (A) solution (40% by weight) is diluted to 20% by weight with ethyl acetate, and 100 parts by weight of this solution is mixed with 2 parts by weight of the ionic liquid (1) (10% by weight toluene solution), hexa Add 0.6 parts by weight of isocyanurate of methylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) and 0.4 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst. An acrylic pressure-sensitive adhesive solution (1) was prepared by mixing and stirring for a minute.

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

[Example 2]
(Preparation of adhesive composition)
The same as Example 1 except that 6 parts by weight of the ionic liquid (2) (10% by weight toluene solution) was used instead of 2 parts by weight of the ionic liquid (1) (10% by weight toluene solution). Thus, an acrylic pressure-sensitive adhesive solution (2) 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 (2) was used instead of the acrylic pressure-sensitive adhesive solution (1).

Example 3
(Preparation of adhesive composition)
Example 1 was used except that 6 parts by weight of the ionic liquid (3) (10% by weight toluene solution) was used instead of 2 parts by weight of the ionic liquid (1) (10% by weight toluene solution). Thus, an acrylic pressure-sensitive adhesive 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).

Example 4
(Preparation of adhesive composition)
Example 1 was used except that 16 parts by weight of the ionic liquid (4) (10% by weight toluene solution) was used instead of 2 parts by weight of the ionic liquid (1) (10% by weight toluene solution). Thus, an acrylic pressure-sensitive adhesive 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).

Example 5
(Preparation of adhesive composition)
The acrylic polymer (A) solution (40% by weight) was replaced with 100 parts by weight of a solution diluted to 20% by weight with ethyl acetate, and the acrylic polymer (B) solution (40% by weight) was 20% by weight with ethyl acetate. Acrylic pressure-sensitive adhesive solution (5) was prepared in the same manner as in Example 1 except that 100 parts by weight of the solution diluted to% 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 (5) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 1]
(Preparation of adhesive composition)
The acrylic polymer (A) solution (40% by weight) is diluted to 20% by weight with ethyl acetate, and 100 parts by weight of this solution is mixed with 2 parts by weight of the ionic liquid (1) (10% by weight toluene solution), hexa Add 0.8 parts by weight of isocyanurate of methylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) and 0.4 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst, and add about 1 at 25 ° C. An acrylic pressure-sensitive adhesive solution (6) was prepared by mixing and stirring for a minute.

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

[Comparative Example 2]
(Preparation of adhesive composition)
The acrylic polymer (A) solution (40% by weight) was replaced with 100 parts by weight of a solution diluted to 20% by weight with ethyl acetate, and the acrylic polymer (B) solution (40% by weight) was 20% by weight with ethyl acetate. An acrylic pressure-sensitive adhesive solution (7) was prepared in the same manner as in Comparative Example 1, except that 100 parts by weight of the solution diluted to% 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 (7) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 3]
(Preparation of adhesive composition)
Example 2 was used except that 2 parts by weight of the ionic liquid (5) (10% by weight toluene solution) was used instead of 2 parts by weight of the ionic liquid (1) (10% by weight toluene solution). Thus, an acrylic pressure-sensitive adhesive solution (8) 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 (8) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 4]
(Preparation of adhesive composition)
The same as Example 1 except that 2 parts by weight of the ionic liquid (6) (10% by weight toluene solution) was used instead of 2 parts by weight of the ionic liquid (1) (10% by weight toluene solution). Thus, an acrylic pressure-sensitive adhesive solution (9) 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 (9) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 5]
(Preparation of adhesive composition)
The acrylic polymer (A) solution (40% by weight) is diluted to 20% by weight with ethyl acetate, and 100 parts by weight of this solution is added with 2.6 parts by weight of the antistatic agent solution (a) (50% by weight), Add 0.4 parts by weight of isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) and 0.4 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst. An acrylic pressure-sensitive adhesive solution (10) was prepared by mixing and stirring for 1 minute.

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

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

According to the results of Table 1 above, when the pressure-sensitive adhesive composition prepared according to the present invention was used (Examples 1 to 5), the stripping voltage to the polarizing plate was suppressed in all the examples, and contamination was generated. It became clear that there was no.

On the other hand, in the case where no ionic liquid was used (Comparative Examples 1 and 2), no occurrence of contamination was observed in any case, but the peeling voltage to the polarizing plate surface-treated with a fluororesin was high. As a result. Moreover, when the ionic liquid which does not have toluene solubility was used (Comparative Examples 3-4), the result was that the stripping voltage to the polarizing plate surface-treated with the fluororesin was high. Furthermore, when an antistatic agent comprising a polyether polyol and an alkali metal salt was used (Comparative Example 5), although the stripping voltage was suppressed, the occurrence of contamination was observed. Therefore, in all of the comparative examples, it is impossible to achieve both suppression of the peeling voltage to the polarizing plate as the adherend and suppression of the occurrence of contamination, which is not suitable for the pressure-sensitive adhesive composition for the pressure-sensitive adhesive sheet. It became clear.

Moreover, as for the adhesive sheet of Examples 1-5 of this invention, all have a 180 degree peel adhesive force in the range of 0.1-6 N / 25mm, and it turns out that it is an adhesive sheet applicable as an adhesive sheet use.

Claims (9)

A toluene-soluble ionic liquid and a polymer having a glass transition temperature Tg of 0 ° C. or lower as a base polymer;
The pressure-sensitive adhesive composition, wherein the toluene-soluble ionic liquid is liquid at room temperature (25 ° C.). The pressure-sensitive adhesive composition according to claim 1, wherein the ionic liquid is at least one of a nitrogen-containing onium salt, a sulfur-containing onium salt, and a phosphorus-containing onium salt. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein the ionic liquid contains one or more cations represented by the following general formulas (A) to (D).

[R _a in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms, and may include a hetero atom, and R _b and R _c may be the same or different, and may be hydrogen or 1 to 16 carbon atoms. 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 may be the same or different, It represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
_{[R h} in the formula (C) represents a hydrocarbon group having from 2 to 20 carbon atoms, and may contain a hetero _atom, R i, _{R j,} and _{R k} are the same or different, hydrogen or carbon atoms It 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 . ] Wherein the ionic liquid, _{CF 3} SO 3 ^- pressure-sensitive adhesive composition according to claim 1 containing an anionic. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, comprising an ether group-containing compound. 6. The polymer having a glass transition temperature Tg of 0 ° C. or lower is a (meth) acrylic polymer mainly comprising at least one of acrylate and / or methacrylate having an alkyl group having 1 to 14 carbon atoms. The pressure-sensitive adhesive composition according to any one of the above. The adhesive layer formed by bridge | crosslinking the adhesive composition in any one of Claims 1-6. 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 on a support. A pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition according to any one of claims 1 to 6 is formed on one side or both sides on a support made of a plastic substrate subjected to antistatic treatment. Characteristic surface protective film.