JP5382883B2 - Adhesive composition, adhesive sheet, and surface protective film - Google Patents

Description

  The present invention relates to a pressure-sensitive adhesive composition having antistatic properties and antistatic pressure-sensitive adhesive sheets made into a sheet-like or tape-like form using the same.

  The pressure-sensitive adhesive sheets made of the pressure-sensitive adhesive composition of the present invention are suitably used for plastic products and the like that easily generate static electricity. Especially, it is useful as an antistatic pressure-sensitive adhesive sheet and pressure-sensitive adhesive tape 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 or peeling. Accordingly, static electricity is generated when the protective film is peeled off from the optical member such as a polarizing plate. If a voltage is applied to the liquid crystal while static electricity remains, the alignment of the 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, one or more low-molecular surfactants are added to the adhesive, and the surfactant is transferred from the adhesive to the adherend and charged. A method for preventing this is disclosed (for example, see Patent Document 1). However, in the present invention, these low molecular surfactants are likely to bleed on the pressure-sensitive adhesive surface, and when applied to a protective film, there is a concern about contamination of the adherend. Therefore, when a pressure-sensitive adhesive to which a low molecular surfactant is added is applied to the protective film for an optical member, it is difficult to develop sufficient antistatic properties without impairing the optical properties of the optical member.

JP-A-9-165460

  In light of such circumstances, the present invention is a pressure-sensitive adhesive composition excellent in adhesion reliability, capable of preventing electrification at the time of peeling of an uncharged adherend, reducing contamination on the adherend, and An object is to provide an antistatic pressure-sensitive adhesive sheet and a surface protective film using the same.

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

  That is, the pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition comprising an ionic liquid and a polymer having a glass transition temperature (Tg) of 0 ° C. or less as a base polymer, and the anionic component of the ionic liquid. Consists of a sulfonate anion or a sulfate ester anion.

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

  According to the pressure-sensitive adhesive composition of the present invention, as shown in the results of Examples, a polymer having a glass transition temperature (Tg) of 0 ° C. or lower as a base polymer, and an anion component is a sulfonate anion or a sulfate ester anion. Since the pressure-sensitive adhesive layer that has been cross-linked with the adhesive liquid contains an adhesive liquid, it is possible to prevent the object to be protected (adhered body) that is not antistatic when peeled off, and the contamination of the object to be protected is reduced. Excellent adhesive properties. Although the details of the reason why such characteristics are exhibited by using the ionic liquid are not clear, the ionic liquid acts as an antistatic agent, and by using the ionic liquid, the ionic liquid as the antistatic agent is used. A pressure-sensitive adhesive composition is obtained in which bleed is suppressed and contamination of the adherend is suppressed over time and at high temperatures.

  Although the details of the reason why bleeding is suppressed by using an ionic liquid as described above are not clear, it is presumed as follows. It is considered that the antistatic effect by the surfactant having a long chain alkyl group or the like is manifested by the surface of the surfactant bleed and the formation of a charge leakage layer with moisture in the air. On the other hand, since the ionic liquid is in a liquid state, the molecular movement is easier than that of the surfactant, and the rearrangement of molecules is likely to occur due to the generation of electric charges. Therefore, in the case of an ionic liquid, since a charge neutralization mechanism by molecular rearrangement works, it is considered that an excellent antistatic effect can be obtained without bleed on the surface as compared with the surfactant.

  In addition, since the ionic liquid is liquid at 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.

  Furthermore, the ionic liquid in the present invention is characterized in that the anion component is composed of a sulfonate anion or a sulfate ester anion. Such an anion component is available at a lower cost than the hexafluorophosphate anion, bis (trifluoromethanesulfonyl) imide anion, and the like, and has the advantage that a lower cost ionic liquid can be obtained.

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

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

  Further, the polymer having a glass transition temperature (Tg) of 0 ° C. or lower is a (meth) acrylic polymer having as a main component at least one (meth) acrylate having an alkyl group having 1 to 14 carbon atoms. Is preferred. By using these (meth) acrylic polymers, the balance between the compatibility of the ionic liquid and the base polymer is improved, and the adhesive properties can be sufficiently maintained.

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

  Moreover, in the adhesive composition of this invention, it is preferable to use the polymer which has an ether group containing monomer as a monomer component as a base polymer. By using a polymer having an ether group-containing monomer, compatibility with the ionic liquid is improved, bleeding to the adherend is suppressed, and a low-contamination pressure-sensitive adhesive composition is obtained.

  The ether group-containing monomer in the present invention is a monomer component containing an ether group and has a reactive substituent such as an acryloyl group, a methacryloyl group, or an allyl group.

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

  The pressure-sensitive adhesive sheet of the present invention is characterized in that a pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition described above is formed on one side or both sides of a support. According to the pressure-sensitive adhesive sheet of the present invention, since it has a pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition having the above-described effects, the anti-static to the adherend not subjected to the antistatic treatment when peeled off. Thus, pressure-sensitive adhesive sheets with excellent adhesion reliability with reduced contamination of the adherend are obtained.

  Furthermore, when the pressure-sensitive adhesive composition of the present invention is applied to a surface protective film, the plastic substrate used for the protective film is more preferably subjected to antistatic treatment. By subjecting the plastic substrate to an antistatic treatment, it is possible to more effectively reduce the stripping voltage on the adherend, and further to obtain an excellent antistatic ability. According to the surface protective film of the present invention, since it has a pressure-sensitive adhesive layer formed by cross-linking the pressure-sensitive adhesive composition having the above-described effects, the anti-static to the adherend not subjected to the antistatic treatment when peeled off. Thus, a protective film having excellent adhesion reliability with reduced contamination on the adherend is obtained. For this reason, it is very useful as an antistatic protective film in a technical field related to electronic equipment, in which electrostatic charge and contamination are particularly serious problems.

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

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

  The pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition comprising an ionic liquid and a polymer having a glass transition temperature (Tg) of 0 ° C. or lower as a base polymer, and the anionic component of the ionic liquid is sulfone. It consists of an acid anion or a sulfate ester anion.

  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 of the present invention, an ionic liquid composed of a sulfonate anion represented by the following general formula (E) or a sulfate ester anion component represented by the following general formula (F) is used.

R ₁ and R ₂ represent a hydrocarbon group having 1 to 50 carbon atoms and may contain a hetero atom.

Among these, R ₁ is preferably an alkyl group having 4 to 40 carbon atoms, an aryl group, or an alkylaryl group, and more preferably an alkyl group having 6 to 36 carbon atoms, an aryl group, or an alkylaryl group.

Specific examples of R ₁ include, for example, alkylbenzene groups such as benzene, toluene, xylene, dodecylbenzene and pentadecylbenzene, alkylnaphthalene groups such as propylnaphthalene, dipropylnaphthalene, butylnaphthalene and dibutylnaphthalene, nonyldiphenyl ether, Examples thereof include alkylphenyl ether groups such as dodecyl diphenyl ether.

As the _{R 2,} an alkyl group having 4 to 40 carbon atoms, an aryl group, alkylaryl group is preferable, and more preferably an alkyl group having 6 to 16 carbon atoms.

Specific examples of R ₂ include alkyl groups such as hexyl, 2-ethylhexyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, and polyoxyethylene alkyl ether groups such as polyoxyethylene dodecyl ether.

  The ionic liquid in the present invention is not particularly limited as long as it is a molten salt (ionic compound) composed of the anionic component and exhibiting a liquid state at room temperature (25 ° C.), but is not limited to nitrogen-containing onium salt, sulfur-containing onium salt, or Phosphonium salts are preferably used, and those composed of the organic cation components represented by the following general formulas (A) to (D) and the above anionic components are preferably used because particularly excellent antistatic ability is obtained.

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

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

  Specific examples include, for example, 1-ethylpyridinium cation, 1-butylpyridinium cation, 1-hexylpyridinium cation, 1-butyl-3-methylpyridinium cation, 1-butyl-4-methylpyridinium cation, 1-hexyl. -3-methylpyridinium cation, 1-butyl-3,4-dimethylpyridinium cation, 1,1-dimethylpyrrolidinium cation, 1-ethyl-1-methylpyrrolidinium cation, 1-methyl-1-propylpyrrolidi Cation, 1-methyl-1-butylpyrrolidinium cation, 1-methyl-1-pentylpyrrolidinium cation, 1-methyl-1-hexylpyrrolidinium cation, 1-methyl-1-heptylpyrrolidinium cation 1-ethyl-1-propylpyrrolidini Cation, 1-ethyl-1-butylpyrrolidinium cation, 1-ethyl-1-pentylpyrrolidinium cation, 1-ethyl-1-hexylpyrrolidinium cation, 1-ethyl-1-heptylpyrrolidinium cation, 1,1-dipropylpyrrolidinium cation, 1-propyl-1-butylpyrrolidinium cation, 1,1-dibutylpyrrolidinium cation, 1-propylpiperidinium cation, 1-pentylpiperidinium cation, 1 , 1-dimethylpiperidinium cation, 1-methyl-1-ethylpiperidinium cation, 1-methyl-1-propylpiperidinium cation, 1-methyl-1-butylpiperidinium cation, 1-methyl-1 -Pentylpiperidinium cation, 1-methyl-1-hexylpiperidi Cation, 1-methyl-1-heptylpiperidinium cation, 1-ethyl-1-propylpiperidinium cation, 1-ethyl-1-butylpiperidinium cation, 1-ethyl-1-pentylpiperidinium cation, 1-ethyl-1-hexylpiperidinium cation, 1-ethyl-1-heptylpiperidinium cation, 1,1-dipropylpiperidinium cation, 1-propyl-1-butylpiperidinium cation, 1-propyl -1-pentylpiperidinium cation, 1-propyl-1-hexylpiperidinium cation, 1-propyl-1-heptylpiperidinium cation, 1,1-dibutylpiperidinium cation, 1-butyl-1-pentyl Piperidinium cation, 1-butyl-1-hexylpiperidinium Cations, 1-butyl-1-heptylpiperidinium cation, 2-methyl-1-pyrroline cation, 1-ethyl-2-phenylindole cation, 1,2-dimethylindole cation, 1-ethylcarbazole cation and the like. .

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

  Specific examples include, for example, 1,3-dimethylimidazolium cation, 1,3-diethylimidazolium cation, 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, and 1-helium. Xyl-3-methylimidazolium cation, 1-octyl-3-methylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-tetradecyl-3-methylimidazole 1-hexadecyl-3-methylimidazolium cation, 1-octadecyl-3-methylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-ethyl-2,3-dimethylimidazolium cation 1-butyl-2, -Dimethylimidazolium cation, 1-hexyl-2,3-dimethylimidazolium cation, 1,3-dimethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3-trimethyl-1, 4,5,6-tetrahydropyrimidinium cation, 1,2,3,4-tetramethyl-1,4,5,6-tetrahydropyrimidinium cation, 1,2,3,5-tetramethyl-1, 4,5,6-tetrahydropyrimidinium cation, 1,3-dimethyl-1,4-dihydropyrimidinium cation, 1,3-dimethyl-1,6-dihydropyrimidinium cation, 1,2,3- Trimethyl-1,4-dihydropyrimidinium cation, 1,2,3-trimethyl-1,6-dihydropyrimidinium cation, 1,2,3,4-tetra Chill-1,4-dihydropyrimidinium cation, such as 1,2,3,4-tetramethyl-1,6-dihydropyrimidinium cation.

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

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

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

  Specific examples include, for example, tetramethylammonium cation, tetraethylammonium cation, tetrapropylammonium cation, tetrabutylammonium cation, tetrapentylammonium cation, tetrahexylammonium cation, tetraheptylammonium cation, trimethylheptylammonium cation, trimethyldecylammonium. Cation, triethylmethylammonium cation, triethylpropylammonium cation, triethylpentylammonium cation, triethylhexylammonium cation, triethylheptylammonium cation, tributylethylammonium cation, tripentylbutylammonium cation, trihexylmethylammonium cation, Lihexylpentylammonium cation, triheptylmethylammonium cation, triheptylhexylammonium cation, trioctylmethylammonium cation, glycidyltrimethylammonium cation, diallyldimethylammonium cation, N, N-dimethyl-N, N-dipropylammonium cation, N , N-dimethyl-N, N-dihexylammonium cation, N, N-dipropyl-N, N-dihexylammonium cation, N, N-dimethyl-N-ethyl-N-propylammonium cation, N, N-dimethyl-N -Ethyl-N-butylammonium cation, N, N-dimethyl-N-ethyl-N-pentylammonium cation, N, N-dimethyl-N-ethyl-N-hexylammonium cation ON, N, N-dimethyl-N-ethyl-N-heptylammonium cation, N, N-dimethyl-N-ethyl-N-nonylammonium cation, N, N-dimethyl-N-propyl-N-butylammonium cation, N, N-dimethyl-N-propyl-N-pentylammonium cation, N, N-dimethyl-N-propyl-N-hexylammonium cation, N, N-dimethyl-N-propyl-N-heptylammonium cation, N, N-dimethyl-N-butyl-N-hexylammonium cation, N, N-dimethyl-N-butyl-N-heptylammonium cation, N, N-dimethyl-N-pentyl-N-hexylammonium cation, N, N- Dimethyl-N-hexyl-N-heptylammonium cation, N, N-die Tyl-N-methyl-N-propylammonium cation, N, N-diethyl-N-methyl-N-pentylammonium cation, N, N-diethyl-N-methyl-N-heptylammonium cation, N, N-diethyl- N-methyl-N- (2-methoxyethyl) ammonium cation, N, N-diethyl-N-propyl-N-pentylammonium cation, N, N-dipropyl-N-methyl-N-ethylammonium cation, N, N -Dipropyl-N-methyl-N-pentylammonium cation, N, N-dipropyl-N-butyl-N-hexylammonium cation, N, N-dibutyl-N-methyl-N-pentylammonium cation, N, N-dibutyl -N-methyl-N-hexylammonium cation, N-methyl-N-ethyl Ru-N-propyl-N-pentylammonium cation, trimethylsulfonium cation, triethylsulfonium cation, tributylsulfonium cation, trihexylsulfonium cation, dimethyldecylsulfonium cation, diethylmethylsulfonium cation, dibutylethylsulfonium cation, tetramethylphosphonium cation, tetraethyl Examples include phosphonium cation, tetrabutylphosphonium cation, tetrapentylphosphonium cation, tetrahexylphosphonium cation, tetraheptylphosphonium cation, tetraoctylphosphonium cation, trimethyldecylphosphonium cation, triethylmethylphosphonium cation, and tributylethylphosphonium cation.

  Among them, trimethylheptylammonium cation, trimethyldecylammonium cation, triethylmethylammonium cation, triethylpropylammonium cation, triethylpentylammonium cation, triethylhexylammonium cation, triethylheptylammonium cation, tributylethylammonium cation, tripentylbutylammonium cation, tripentylbutylammonium cation Hexylmethylammonium cation, trihexylpentylammonium cation, triheptylmethylammonium cation, triheptylhexylammonium cation, trioctylmethylammonium cation, glycidyltrimethylammonium cation, N, N-dimethyl-N-ethyl-N-propylammonium cation ON, N, N-dimethyl-N-ethyl-N-butylammonium cation, N, N-dimethyl-N-ethyl-N-pentylammonium cation, N, N-dimethyl-N-ethyl-N-hexylammonium cation, N, N-dimethyl-N-ethyl-N-heptylammonium cation, N, N-dimethyl-N-ethyl-N-nonylammonium cation, N, N-dimethyl-N-propyl-N-butylammonium cation, N, N-dimethyl-N-propyl-N-pentylammonium cation, N, N-dimethyl-N-propyl-N-hexylammonium cation, N, N-dimethyl-N-propyl-N-heptylammonium cation, N, N- Dimethyl-N-butyl-N-hexylammonium cation, N, N-dimethyl N-butyl-N-heptylammonium cation, N, N-dimethyl-N-pentyl-N-hexylammonium cation, N, N-dimethyl-N-hexyl-N-heptylammonium cation, N, N-diethyl-N- Methyl-N-propylammonium cation, N, N-diethyl-N-methyl-N-pentylammonium cation, N, N-diethyl-N-methyl-N-heptylammonium cation, N, N-diethyl-N-methyl- N- (2-methoxyethyl) ammonium cation, N, N-diethyl-N-propyl-N-pentylammonium cation, N, N-dipropyl-N-methyl-N-ethylammonium cation, N, N-dipropyl-N -Methyl-N-pentylammonium cation, N, N-dipropyl-N -Butyl-N-hexylammonium cation, N, N-dibutyl-N-methyl-N-pentylammonium cation, N, N-dibutyl-N-methyl-N-hexylammonium cation, N-methyl-N-ethyl-N Asymmetric tetraalkylammonium cations such as propyl-N-pentylammonium cation, dimethyldecylsulfonium cation, diethylmethylsulfonium cation, trialkylsulfonium cation such as dibutylethylsulfonium cation, trimethyldecylphosphonium cation, triethylmethylphosphonium cation, tributylethyl Asymmetric tetraalkylphosphonium cations such as phosphonium cations are preferably used.

  Specific examples of the ionic liquid used in the present invention are appropriately selected from a combination of the cation component and the anion component.

  Specific examples include 1-ethylimidazolium benzenesulfonate, 1-ethyl-3-methylimidazolium-p-toluenesulfonate, 1,3-diethylimidazolium-p-toluenesulfonate, N-hexyl-N, Examples thereof include N-dimethyl-N-octylammonium dodecyl benzene sulfonate, tetraoctyl ammonium dodecyl benzene sulfonate, 1-butyl-3-methylpyridinium dodecyl sulfate, and tetraoctyl ammonium sulfate.

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

  The synthesis method for the halide method, hydroxide method, and acid ester method will be described below using nitrogen-containing onium salts as examples, but the same applies to other ionic liquids such as other sulfur-containing onium salts and phosphorus-containing onium salts. It can be obtained by a technique.

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

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

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

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

The acid ester method is a method performed by reactions as shown in (9) to (11). First, a tertiary amine (R ₃ N) is reacted with an acid ester to obtain an acid ester product (Reaction Formula (9)). As the acid ester, inorganic acids such as sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid, and carbonic acid 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. Moreover, an ionic liquid can also be obtained directly by using sulfate ester, sulfite ester, etc. as acid ester.

  R described in (1) to (11) above represents hydrogen or a hydrocarbon group having 1 to 40 carbon atoms, and may contain a hetero atom.

  The ionic liquids may be used alone or in combination of two or more.

  The blending amount of the ionic liquid cannot be defined unconditionally because it varies depending on the compatibility of the polymer to be used and the ionic liquid, but is generally 0.01 to 40 weights with respect to 100 parts by weight of the base polymer. Part is preferable, 0.03 to 20 parts by weight is more preferable, and 0.05 to 10 parts by weight is further 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 mainly containing one or more of (meth) acrylates having 1 to 14 carbon atoms. Polymer (SIS block copolymer), Styrene-butadiene-styrene block copolymer (SBS block copolymer), Styrene-ethylene-butylene-styrene block copolymer (SEBS block copolymer), Styrene-butadiene rubber, Polymers generally applied as the adhesive polymer such as polybutadiene, polyisoprene, polyisobutylene, butyl rubber, chloroprene rubber, and silicone rubber are listed.

  Among these, since the balance of compatibility with the ionic liquid and excellent adhesive properties can be obtained, the main component is one or more of (meth) acrylates having an alkyl group having 1 to 14 carbon atoms. (Meth) acrylic polymers are preferred.

  Specific examples of the (meth) acrylate having an alkyl group having 1 to 14 carbon atoms include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, 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-undecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) Ak Rate 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). 6 carbon atoms such as acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate (Meth) acrylates having ˜14 alkyl groups are preferred. By using (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 the removability is excellent.

  The (meth) acrylate having an alkyl group having 1 to 14 carbon atoms may be used alone, or two or more kinds may be mixed and used, but the total content is (meth) acrylic. The content is preferably 50 to 100% by weight, more preferably 60 to 99% by weight, and particularly preferably 70 to 96% by weight, based on all monomer components of the polymer. If the (meth) acrylate is less than 50% by weight, good adhesive force and holding force required as pressure-sensitive adhesive sheets may not be obtained.

  Further, as another polymerizable monomer component, the glass transition temperature of the (meth) acrylic polymer is set so that the Tg is 0 ° C. or lower (usually −100 ° C. or higher) because the adhesive performance is easily balanced. And a polymerizable monomer for adjusting the peelability can be used as long as the effects of the present invention are not impaired.

  Other polymerizable monomers used in (meth) acrylic polymers include, for example, cohesion and heat resistance of sulfonic acid group-containing monomers, phosphate group-containing monomers, cyano group-containing monomers, vinyl esters, aromatic vinyl compounds, etc. Improvement of adhesive properties such as carboxyl 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, vinyl ethers, A component having a functional group serving as a crosslinking base point can be appropriately used. These monomer compounds may be used alone or in admixture of two or more.

  However, when (meth) acrylate having an acid functional group such as a sulfonic acid group-containing monomer, a carboxyl group-containing monomer, an acid anhydride group-containing monomer, or a phosphoric acid group-containing monomer is used, the acid value of the (meth) acrylic polymer It is preferable to prepare such that is 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, an acrylic polymer obtained by copolymerizing 2-ethylhexyl acrylate and acrylic acid as an acrylic polymer having a carboxyl group. In this case, acrylic acid can be 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, and the acid value can be made 29 or less. .

  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, (meth And acryloyloxynaphthalene sulfonic acid, sodium vinyl sulfonate and the like.

  Examples of the phosphoric acid group-containing monomer include 2-hydroxyethylacryloyl phosphate.

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

  Examples of the 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, and other substituted styrene.

  Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Of these, acrylic acid and methacrylic acid are particularly preferably used.

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

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

  Examples of the amide group-containing monomer include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, and N, N-diethyl. Examples include methacrylamide, N, N′-methylenebisacrylamide, N, N-dimethylaminopropyl acrylamide, N, N-dimethylaminopropyl methacrylamide, diacetone acrylamide, and the like.

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

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

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

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

  Among the other polymerizable monomers described above, (meth) acrylate having a hydroxyl group is preferably used because the crosslinking can be easily controlled.

  In the present invention, the above-mentioned other polymerizable monomers may be used alone or in combination of two or more, but the total content is a single (meth) acrylic polymer. It is preferably less than 50% by weight of the monomer component, more preferably 0.1 to 40% by weight, and particularly preferably 0.5 to 20% by weight. By using other polymerizable monomers, good interaction with the ionic liquid and good adhesion can be appropriately adjusted.

  Furthermore, as the (meth) acrylic polymer of the present invention, an ether group-containing monomer such as an alkylene glycol group-containing (meth) acrylate or an alkylene oxide group-containing reactive surfactant is used in order to develop further excellent low contamination. Can be used as a copolymerization component.

  Although the details of the reason why such characteristics are manifested by copolymerizing an ether group-containing monomer are not clear, the ionic liquid is coordinated with an ether group such as an alkylene oxide group-containing reactive surfactant. Is less likely to bleed, and is presumed to have achieved excellent antistatic properties and low contamination in parallel.

  As the alkylene glycol group-containing (meth) acrylate, a (meth) acrylate having an alkylene group having 1 to 6 carbon atoms as an oxyalkylene unit is preferably used. Specific examples of the alkylene group include 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, 1-50 are preferable and 2-30 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 methoxy-polyethylene glycol (meth) acrylate type such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) acrylate, ethoxy-diethylene glycol (meth) acrylate, Ethoxy-polyethylene glycol (meth) acrylate type such as ethoxy-triethylene 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) acryl Phenoxy, such as over bets - polyethylene glycol (meth) acrylate type, methoxy - methoxy dipropylene glycol (meth) acrylate - polypropylene glycol (meth) acrylate type and the like.

  The alkylene glycol group-containing (meth) acrylate may be used alone or in combination, but the blending amount is less than 50% by weight in the monomer component of the (meth) acrylic polymer. Is preferable, and it is more preferable that it is 0.05 to 30 weight%. When the alkylene glycol group-containing (meth) acrylate is less than 50 parts by weight, the antistatic effect and the contamination-reducing effect of the protected body can be easily aligned.

  The alkylene oxide group-containing reactive surfactant in the present invention refers to an alkylene oxide group-containing compound having a reactive unsaturated bond. Specific examples include an anionic reactive surfactant, a nonionic reactive surfactant, and a cationic reactive surfactant having an acryloyl group, a methacryloyl group, or an allyl group. Among these, an anionic reactive surfactant, a nonionic reactive surfactant, a cationic reactive surfactant, or the like having an acryloyl group having a ethylene oxide group, a methacryloyl group, or an allyl group is preferably used.

  Examples of the anionic reactive surfactant include those represented by formulas (A1) to (A13).

[R ₁ in Formula (A1) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or acyl group having 1 to 30 carbon atoms, M represents an alkali metal, alkaline earth metal, ammonium group, or carbon A hydroxyalkylammonium group having 1 to 4 atoms, R ₃ and R ₄ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, n is 0 to 50, and m is a number from 0 to 20. ]

[R ₁ in Formula (A2) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or an acyl group having 1 to 30 carbon atoms, and R ₃ and R ₄ may be the same or different, and 6 represents an alkylene group, and M ₁ and M ₂ are the same or different and each represents an alkali metal, an alkaline earth metal, an ammonium group, or a hydroxyalkylammonium group having 1 to 4 carbon atoms, and n is 0 to 50, m Represents a number from 0 to 20. ]

[R ₁ in Formula (A3) represents hydrogen or a methyl group, R ₂ and R ₇ are the same or different, represent an alkylene group having 1 to 6 carbon atoms, and R ₃ and R ₅ are the same or different, R ₄ and R ₆ are the same or different and each represents hydrogen, an alkyl group, a benzyl group, or a styrene group; M represents an alkali metal, alkaline earth metal, or ammonium group; and n and m Represents a number from 1 to 50. ]

[R ₁ in Formula (A4) represents hydrogen or a methyl group, R ₂ represents an alkylene group having 1 to 6 carbon atoms, M represents an alkali metal, alkaline earth metal, or ammonium group, and n represents 2 To a number of 50. ]

[R ₁ in Formula (A5) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or an acyl group having 1 to 30 carbon atoms, and R ₃ and R ₄ may be the same or different, and 6 represents an alkylene group, M represents an alkali metal, alkaline earth metal, ammonium group, or a hydroxyalkylammonium group having 1 to 4 carbon atoms, n represents 0 to 50, and m represents a number from 0 to 20. ]

[R ₁ in Formula (A6) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or an acyl group having 1 to 30 carbon atoms, and R ₃ and R ₄ may be the same or different, and 6 represents an alkylene group, and M ₁ and M ₂ are the same or different and each represents an alkali metal, an alkaline earth metal, an ammonium group, or a hydroxyalkylammonium group having 1 to 4 carbon atoms, and n is 0 to 50, m Represents a number from 0 to 20. ]

[R ₁ in Formula (A7) represents a hydrocarbon group, an amino group, or a carboxylic acid residue, R ₂ represents an alkylene group having 1 to 6 carbon atoms, and n represents a number from 0 to 50. ]

[In Formula (A8), R ₁ represents a hydrocarbon group having 1 to 30 carbon atoms, R ₂ represents hydrogen or a hydrocarbon group having 1 to 30 carbon atoms, R ₃ represents hydrogen or a propenyl group, and R ₄ represents Represents an alkylene group having 1 to 6 carbon atoms, M represents an alkali metal, alkaline earth metal, ammonium group, or alkanolamine residue, and n represents a number of 1 to 50. ]

[R ₁ in Formula (A9) represents hydrogen or a methyl group, R ₂ and R ₄ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, and R ₃ represents a hydrocarbon having 1 to 30 carbon atoms. Represents a group, M represents hydrogen, an alkali metal, an alkaline earth metal, an ammonium group or an alkanol ammonium group, and n and m represent a number of 1 to 50. ]

[R ₁ and R _{5 in} Formula (A10) are the same or different and each represents hydrogen or a methyl group; R ₂ and R ₄ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms; and R ₃ represents A hydrocarbon group having 1 to 30 carbon atoms, M represents hydrogen, an alkali metal, an alkaline earth metal, an ammonium group, or an alkanol ammonium group, and n and m represent a number of 1 to 50. ]

“R ₁ in the formula (A11) represents an alkylene group having 1 to 6 carbon atoms, R ₂ represents a hydrocarbon group having 1 to 30 carbon atoms, and M represents hydrogen, an alkali metal, an alkaline earth metal, or an ammonium group. Or an amine group, and n represents a number from 1 to 50.]

[R ₁ , R ₂ and R _{3 in} Formula (A12) are the same or different and represent hydrogen or a methyl group, and R ₄ represents a hydrocarbon group having 0 to 30 carbon atoms (in the case of 0 carbon atoms, R ₄ R ₅ and R ₆ are the same or different and each represents an alkylene group having 1 to 30 carbon atoms, m represents a number from 0 to 50, n represents a number from 0 to 50, (M + n) represents a number from 1 to 50, and M represents hydrogen, an alkali metal, an alkaline earth metal, an ammonium group, or an alkanol ammonium group. ]

[R ₁ , R ₂ and R _{3 in} Formula (A13) are the same or different and represent hydrogen or a methyl group, and R ₄ represents a hydrocarbon group having 0 to 30 carbon atoms (in the case of 0 carbon atoms, R ₄ R ₅ and R ₆ are the same or different and each represents an alkylene group having 1 to 30 carbon atoms, m represents a number from 0 to 50, n represents an integer from 0 to 50, (M + n) represents a number from 1 to 50, and M ₁ and M ₂ are the same or different and each represents hydrogen, an alkali metal, an alkaline earth metal, an ammonium group, or an alkanol ammonium group. ]

  Examples of nonionic reactive surfactants include those represented by formulas (N1) to (N6).

[R ₁ in Formula (N1) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or an acyl group having 1 to 30 carbon atoms, and R ₃ and R ₄ may be the same or different, and 6 represents an alkylene group, and n and m represent a number of 0 to 50. ]

[R ₁ in Formula (N2) represents hydrogen or a methyl group, R ₂ represents a hydrocarbon group or an acyl group having 1 to 30 carbon atoms, and R ₃ and R ₄ may be the same or different, and 6 represents an alkylene group, and n and m represent a number of 0 to 50. ]

[In Formula (N3), R ₁ represents hydrogen or a methyl group, R ₂ and R ₃ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms, and n and m represent a number of 0 to 50. Represent. ]

[R ₁ and R _{2 in} formula (N4) are the same or different and each represents a hydrocarbon group having 1 to 30 carbon atoms, R ₃ represents hydrogen or a propenyl group, and R ₄ represents an alkylene having 1 to 6 carbon atoms Represents a group, and n represents a number from 1 to 50. ]

[R ₁ , R ₂ and R _{3 in} Formula (N5) are the same or different and represent hydrogen or a methyl group, and R ₄ represents a hydrocarbon group having 0 to 30 carbon atoms (in the case of 0 carbon atoms, R ₄ R ₅ and R ₆ are the same or different and each represents an alkylene group having 1 to 30 carbon atoms, m represents a number from 0 to 50, n represents a number from 0 to 50, (M + n) represents a number from 1 to 50. ]

[In Formula (N6), R ₁ and R ₃ are the same or different and each represents an alkylene group having 1 to 6 carbon atoms; R ₂ and R ₄ are the same or different and represent hydrogen, a hydrocarbon group having 1 to 30 carbon atoms or Represents an acyl group, and n and m are 0 to 50, and (n + m) represents a number from 3 to 50. ]

  Examples of the cationic reactive surfactant include those represented by the formulas (C1) to (C2).

[R ₁ and R _{2 in} Formula (C1) are the same or different and each represents an alkyl group having 1 to 30 carbon atoms, R ₃ represents a hydrocarbon group having 1 to 30 carbon atoms, and X represents chlorine or bromine. Represent. ]

    [R in the formula (C2) represents a hydrocarbon group having 1 to 30 carbon atoms and may contain a hetero atom. ]

  The reactive surfactant may be used alone or in combination of two or more, but it may be 20% by weight or less in the monomer component of the (meth) acrylic polymer. Preferably, 0.05 to 10% by weight is more preferable, and 0.1 to 5% by weight is particularly preferable. When the content of the reactive surfactant is 20% by weight or less, the effect of suppressing bleeding of the ionic liquid and the effect of reducing contamination of the protected body in the present invention can be sufficiently obtained.

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

  The polymerization method of the (meth) acrylic polymer is not particularly limited, and can be polymerized by a known method such as solution polymerization, emulsion polymerization, bulk polymerization, suspension polymerization. Further, the polymer obtained may be any of a random copolymer, a block copolymer, an alternating copolymer, a graft copolymer, and the like.

  In the pressure-sensitive adhesive composition of the present invention, pressure-sensitive adhesive sheets having excellent heat resistance can be obtained by appropriately crosslinking a base polymer, particularly a (meth) acrylic polymer. Specific means of the crosslinking method include carboxyl group, hydroxyl group, amino group, amide group and the like appropriately included in (meth) acrylic polymer such as isocyanate compound, epoxy compound, melamine resin, aziridine compound as crosslinking point 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-diglycidyl). Aminomethyl) cyclohexane (trade name: TETRAD-C, manufactured by Mitsubishi Gas Chemical Company, Inc.). These compounds may be used alone or in combination of two or more.

  Examples of the melamine-based resin include hexamethylol melamine. Melamine resins may be used alone or in admixture of two or more.

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

  The amount of these crosslinking agents to be used is appropriately selected depending on the balance with the (meth) acrylic polymer to be crosslinked, and further depending on the intended use as the pressure-sensitive adhesive sheet. In general, in order to obtain sufficient heat resistance by the cohesive strength of the acrylic pressure-sensitive adhesive, it is preferably contained in an amount of 0.01 to 15 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer. More preferably, it is contained in an amount of 5 to 10 parts by weight. When the content is less than 0.01 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.

  In the present invention, a polyfunctional monomer having two or more radiation-reactive unsaturated bonds can be added as a crosslinking agent. In such a case, the pressure-sensitive adhesive composition is crosslinked by irradiating with radiation or the like. As a polyfunctional monomer having two or more radiation-reactive unsaturated bonds in one molecule, for example, it can be crosslinked (cured) by irradiation with radiation such as vinyl group, acryloyl group, methacryloyl group, vinylbenzyl group. Examples thereof include polyfunctional monomers having two or more radiation-reactive unsaturated bonds of one kind or two or more kinds. As the polyfunctional monomer, generally, those having 10 or less radiation-reactive unsaturated bonds are suitably used. These compounds may be used alone or in combination of two or more.

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

  The amount of the polyfunctional monomer 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 of the pressure-sensitive adhesive sheet. In general, in order to obtain sufficient heat resistance by the cohesive force of the acrylic pressure-sensitive adhesive, it is preferably blended in an amount of 0.1 to 30 parts by weight with respect to 100 parts by weight of the (meth) acrylic polymer. Moreover, it is more preferable to mix | blend at 10 weight part or less with respect to 100 weight part of (meth) acrylic-type polymers from the point of a softness | flexibility and adhesiveness.

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

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

  Examples of radical photopolymerization initiators include benzoins such as benzoin, benzoin methyl ether, benzoin ethyl ether, o-benzoylbenzoic acid methyl-p-benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, benzyldimethyl ketal, and trichlor Acetophenones such as acetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methylpropiophenone, 2-hydroxy-4'-isopropyl-2-methylpropiophenone, etc. Propiophenones, benzophenone, methylbenzophenone, p-chlorobenzophenone, benzophenones such as p-dimethylaminobenzophenone, 2-chlorothioxanthone, 2 Thioxanthones such as ethylthioxanthone 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. These compounds may be used alone or in combination of two or more.

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

  The photopolymerization initiator is usually blended in an amount of 0.1 to 10 parts by weight and preferably 0.2 to 7 parts by weight with respect to 100 parts by weight of the acrylic polymer. These photopolymerization initiators may be used alone or in combination of two or more.

  It is also possible to use a photoinitiated polymerization aid such as amines in combination. Examples of the photoinitiator aid include 2-dimethylaminoethyl benzoate, dimethylaminoacetophenone, p-dimethylaminobenzoic acid ethyl ester, p-dimethylaminobenzoic acid isoamyl ester, and the like. These compounds may be used alone or in combination of two or more. It is preferable to mix | blend 0.05-10 weight part with respect to 100 weight part of (meth) acrylic-type polymers, and, as for a polymerization start adjuvant, it is more preferable to mix | blend in the range of 0.1-7 weight part.

  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, there may be a pressure-sensitive adhesive composition having further excellent antistatic properties. The reason why the antistatic property is improved by using the ether group-containing compound is not clear, but the combined use of the ether group-containing compound improves the wettability for non-polar materials such as fluorine, Transfer to the adherend can be performed efficiently.

  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. Of these, ether type surfactants such as polyether polyol compounds, alkylene glycol group-containing (meth) acrylic polymers, and polyoxyalkylene alkyl allyl ethers are preferably used because they have a good balance of compatibility with the base polymer. Can do.

  Examples of the polyether polyol compound include polyethylene glycol, polypropylene glycol (diol type), polypropylene glycol (triol type), polytetramethylene ether glycol, and block copolymers of the above derivatives and polypropylene glycol-polyethylene glycol-polypropylene glycol, Polyethylene glycol-polypropylene glycol block copolymers, polyethylene glycol-polypropylene glycol-polyethylene glycol block copolymers, polypropylene glycol-polyethylene glycol random copolymers, and other random or block copolymers of polyethylene glycol and polypropylene glycol. A polymer.

  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.

  As the alkylene glycol group-containing (meth) acrylic polymer, a (meth) acrylic polymer containing an alkylene glycol group-containing (meth) acrylate as an essential component can be used.

  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, 1-50 are preferable and 2-30 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 methoxy-polyethylene glycol (meth) acrylate type such as methoxy-diethylene glycol (meth) acrylate and methoxy-triethylene glycol (meth) acrylate, ethoxy-diethylene glycol (meth) acrylate, Ethoxy-polyethylene glycol (meth) acrylate type such as ethoxy-triethylene 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) acryl Phenoxy, such as over bets - polyethylene glycol (meth) acrylate type, methoxy - methoxy dipropylene glycol (meth) acrylate - polypropylene glycol (meth) acrylate type and the like.

  In addition to the above components, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, hexyl (Meth) acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isodecyl It is also possible to use (meth) acrylates 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.

  Examples of the phosphoric acid group-containing (meth) acrylate include 2-hydroxyethylacryloyl phosphate.

  Examples of the cyano group-containing (meth) acrylate include acrylonitrile and methacrylonitrile.

  Examples of the 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, and other substituted styrene.

  Examples of the acid anhydride group-containing (meth) acrylate include maleic anhydride, itaconic anhydride, and acid anhydride bodies of the above carboxyl group-containing monomers.

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

  Examples of the amide group-containing (meth) acrylate include acrylamide, methacrylamide, diethylacrylamide, N-vinylpyrrolidone, N, N-dimethylacrylamide, N, N-dimethylmethacrylamide, N, N-diethylacrylamide, N, Examples thereof include N-diethylmethacrylamide, N, N′-methylenebisacrylamide, N, N-dimethylaminopropylacrylamide, N, N-dimethylaminopropylmethacrylamide, diacetoneacrylamide and the like.

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

  Examples of the imide group-containing (meth) acrylate include cyclohexylmaleimide, isopropylmaleimide, N-cyclohexylmaleimide, and itaconimide.

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

  Examples of the 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. If the proportion of the alkylene glycol group-containing (meth) acrylate is less than 10% by weight, sufficient charging characteristics cannot be obtained, while if it exceeds 70% by weight, it is in phase with the (meth) acrylic polymer as the base polymer. The solubility becomes poor and sufficient charging characteristics cannot be obtained.

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

  Furthermore, an ether type surfactant may be used as the ether group-containing compound in the present invention.

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

  Among them, for example, polyoxyethylene fatty acid esters, polyoxyethylene sorbitan fatty acid esters, polyoxyethylene sorbitol fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, polyoxyethylene alkyl phenyl ethers Nonionic surfactants such as polyoxyethylene derivatives, polyoxyethylene alkylamines, polyoxyethylene alkylamine fatty acid esters, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl ether phosphates, polyoxy Anionic surfactants such as ethylene alkylphenyl ether phosphates, cationic surfactants having an ethylene oxide group and amphoteric surfactants That. Moreover, you may have reactive substituents, such as a (meth) acryloyl group and an allyl group, in a molecule | numerator.

  The added mole number of the oxyalkylene unit of the surfactant having an alkylene oxide group is preferably 1 to 50, more preferably 2 to 40, from the viewpoint of interaction with the ionic liquid. When the added mole number of the oxyalkylene unit is less than 1, it is difficult to balance the compatibility with the ionic liquid and the base polymer, and the bleed to the adherend tends to increase, such being undesirable. On the other hand, when a surfactant having an added mole number of oxyalkylene units exceeding 50 is used, the ionic liquid is restrained by the alkylene oxide group and the antistatic property tends to be lowered, which is not preferable.

  Specific examples of ether type surfactants include, for example, ADEKA rear soap NE-10, ADEKA rear soap SE-10N, ADEKA rear soap SE-20N, ADEKA rear soap ER-10, ADEKA rear soap SR-10, and ADEKA rear. Examples include soap SR-20 (manufactured by Asahi Denka Co., Ltd.), Emulgen 120 (manufactured by Kao Corporation), Neugen EA130T (manufactured by 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 200 to 5,000 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 20 parts by weight with respect to 100 parts by weight of the base polymer. More preferably, the amount is 0.05 parts by weight to 5 parts by weight. If the amount is less than 0.01 parts by weight, sufficient charging characteristics cannot be obtained, and if it exceeds 10 parts by weight, contamination of the adherend tends to increase, such being undesirable.

  Furthermore, the pressure-sensitive adhesive composition used for the pressure-sensitive adhesive sheets of the present invention may contain other known additives, for example, powders such as colorants and pigments, surfactants, plasticizers, pressure-sensitive adhesives, and the like. Property-imparting agent, low molecular weight polymer, surface lubricant, leveling agent, antioxidant, corrosion inhibitor, light stabilizer, UV absorber, polymerization inhibitor, silane coupling agent, inorganic or organic filler, metal powder, It can be added as appropriate depending on the application in which particles, foils, etc. are used.

  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. Moreover, the pressure-sensitive adhesive sheets of the present invention are formed by forming such a pressure-sensitive adhesive layer on a support (support film). At that time, the pressure-sensitive adhesive composition is generally crosslinked after application of the pressure-sensitive adhesive composition, but it is also possible to transfer the pressure-sensitive adhesive layer comprising the crosslinked pressure-sensitive adhesive composition to a support 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 for forming the pressure-sensitive adhesive layer on the film is not particularly limited. For example, the pressure-sensitive adhesive composition is coated on a support (support film), and the polymerization solvent is dried and removed to place the pressure-sensitive adhesive layer on the support. It is produced by forming. Thereafter, curing may be performed for the purpose of adjusting the component transfer of the pressure-sensitive adhesive layer or adjusting the crosslinking reaction. In addition, when the pressure-sensitive adhesive composition is applied on a support 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 applied on the support. You may add to.

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

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

  Moreover, it is preferable that the said support body is a plastic base material which has heat resistance and solvent resistance, and has flexibility. When the support has flexibility, the pressure-sensitive adhesive composition can be applied by a roll coater or the like, and can be wound into a roll.

  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・ Polypropylene copolymer, ethylene / 1-butene copolymer, ethylene / vinyl acetate copolymer, ethylene / ethyl acrylate copolymer, polyolefin film such as ethylene / vinyl alcohol copolymer, polyethylene terephthalate, polyethylene naphthalate, Polyester film such as polybutylene terephthalate, polyacrylate film, polystyrene film, nylon 6, nylon 6,6, polyamide film such as partially aromatic polyamide, polyvinyl chloride film, polyvinylidene chloride film, polymer film Such as carbonate film, and the like.

  Moreover, the thickness of the said support body is 5-200 micrometers normally, Preferably it is about 10-100 micrometers.

  If necessary, the above-mentioned support may be released from a silicone, fluorine, long chain alkyl or fatty acid amide release agent, silica powder or other mold release and antifouling treatment, acid treatment, alkali treatment, primer treatment. Further, anti-adhesion treatment such as corona treatment, plasma treatment and ultraviolet treatment, coating type, kneading type, vapor deposition type and the like can be carried out.

  Further, 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, but there are a method of providing an antistatic layer on at least one side of a commonly used substrate and a method of kneading a type antistatic agent into a plastic substrate. Used. As a method of providing an antistatic layer on at least one surface of a base material, a method of applying an antistatic resin or a conductive polymer composed of an antistatic agent and a resin component, a conductive resin containing a conductive substance, or a conductive substance is used. Examples of the method include vapor deposition or plating.

  Antistatic agents contained in the antistatic resin include cationic antistatic agents having cationic functional groups such as quaternary ammonium salts, pyridinium salts, primary, secondary and tertiary amino groups, and sulfonic acids Anionic antistatic agents having an anionic functional group such as salts, sulfate esters, phosphonates and 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 amino alcohol and derivatives thereof, glycerin and derivatives thereof, polyethylene glycol and derivatives thereof, and monomers having an ion conductive group of the above cation type, anion type and zwitterionic type are polymerized Or the ion conductive polymer obtained by copolymerization is mention | raise | lifted. These compounds may be used alone or in combination of two or more.

  Examples of cationic antistatic agents include quaternary ammonium groups such as alkyltrimethylammonium salts, acyloylamidopropyltrimethylammonium methosulfate, alkylbenzylmethylammonium salts, acylcholine chloride, and polydimethylaminoethyl methacrylate (meth). Examples thereof include acrylate copolymers, styrene copolymers having quaternary ammonium groups such as polyvinylbenzyltrimethylammonium chloride, and diallylamine copolymers having quaternary ammonium groups such as polydiallyldimethylammonium chloride. These compounds may be used alone or in combination of two or more.

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

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

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

  Examples of the conductive polymer include polyaniline, polypyrrole, polythiophene and the like. These compounds 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.

  As the resin component used for the antistatic resin and the conductive resin, general-purpose resins such as polyester, acrylic, polyvinyl, urethane, melamine, and epoxy are used. In the case of a polymer type antistatic agent, it is not necessary to contain a resin component. Further, the antistatic resin component 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 substrate. It is formed.

  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 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 compounding 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 substrate. The kneading method is not particularly limited as long as the antistatic agent can be uniformly mixed with the resin used for the plastic substrate. For example, a heating roll, a Banbury mixer, a pressure kneader, a biaxial kneader, or the like is used. Used.

  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 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 separator is usually about 5 to 200 μm, preferably about 10 to 100 μm. If necessary, the separator can be subjected to mold release and antifouling treatment with a silicone, fluorine, long chain alkyl or fatty acid amide release agent, silica powder, and the like.

  The pressure-sensitive adhesive composition, the pressure-sensitive adhesive sheets, and the surface protective film using the present invention are particularly used for plastic products and the like that easily generate static electricity. In particular, it is very useful as a surface protective film used for the purpose of protecting the surface of optical members such as polarizing plates, wave plates, retardation plates, optical compensation films, reflection sheets, and brightness enhancement films used in liquid crystal displays. It becomes.

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

<Measurement of acid value>
The acid value was measured using an automatic titration device (COM-550, manufactured by Hiranuma Sangyo Co., Ltd.) and obtained from the following formula.
A = {(Y−X) × f × 5.611} / M
A: Acid value Y: Titration volume of sample solution (ml)
X: Titration volume of a solution containing only 50 g of mixed solvent (ml)
F: Factor of titration solution M: Weight of polymer sample (g)

The measurement conditions are as follows.
Sample solution: About 0.5 g of a polymer sample was dissolved in 50 g of a mixed solvent (toluene / 2-propanol / distilled water = 50 / 49.5 / 0.5, weight ratio) to obtain a sample solution.
-Titration solution: 0.1N, 2-propanol potassium hydroxide solution (manufactured by Wako Pure Chemical Industries, Ltd., for petroleum product neutralization value test)
-Electrode: Glass electrode; GE-101, Comparative electrode; RE-201
Measurement mode: Petroleum product neutralization value test 1

<Measurement of molecular weight>
The weight average molecular weight was measured using a GPC apparatus (manufactured by Tosoh Corporation, HLC-8220GPC). The measurement conditions are as follows.
Sample concentration: 0.2% by weight (THF solution)
Sample injection volume: 10 μl
・ Eluent: THF
・ Flow rate: 0.6ml / min
・ Measurement temperature: 40 ℃
·column:
Sample column: TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column; TSKgel SuperH-RC (1)
・ Detector: Differential refractometer (RI)
The weight average molecular weight was determined in terms of polystyrene.

<Measurement of glass transition temperature>
The glass transition temperature (Tg) (° C.) was determined by the following method using a dynamic viscoelasticity measuring apparatus (ARES, manufactured by Rheometrics).

  A sheet of (meth) acrylic polymer (thickness: 20 μm) is laminated to a thickness of about 2 mm, and this is punched out to φ7.9 mm to produce a cylindrical pellet to obtain a glass transition temperature (Tg) measurement sample. .

  The measurement sample is fixed to a jig of 7.9 mm parallel plate, the temperature dependence of the loss elastic modulus G ″ is measured by the dynamic viscoelasticity measuring device, and the obtained G ″ curve is maximized. The temperature was the glass transition temperature (° C.).

The measurement conditions are as follows.
・ Measurement: Shear mode ・ Temperature range: −70 ° C. to 150 ° C.
・ Raising rate: 5 ° C / min
・ Frequency: 1 Hz

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

[NMR measurement]
The NMR measurement was performed under the following measurement conditions using a nuclear magnetic resonance apparatus (EX-400, manufactured by JEOL Ltd.).
・ Observation frequency: 400 MHz ( ¹ H), 100 MHz ( ¹³ C)
・ Measurement solvent: acetone-d ₆
・ Measurement temperature: 23 ℃

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

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

<Preparation of (meth) acrylic polymer>
[Acrylic polymer (A)]
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, a cooler, and a dropping funnel, 199 parts by weight of 2-ethylhexyl acrylate, 1 weight of reactive surfactant (manufactured by Kao Corporation, LATEMUL PD-420) 1 part, 2-hydroxyethyl acrylate 8 parts by weight, 2,2′-azobisisobutyronitrile 0.4 part by weight, ethyl acetate 386 parts by weight as a polymerization initiator, and nitrogen gas was introduced while gently stirring. A polymerization reaction was carried out for about 6 hours while maintaining the liquid temperature in the flask at around 60 ° C. to prepare an acrylic polymer (A) solution (35% by weight). The acrylic polymer (A) had a weight average molecular weight of 500,000, a glass transition temperature (Tg) of −10 ° C. or lower, and an acid value of 0.0.

<Preparation of ionic liquid>
[Ionic liquid (1)]
In a four-necked flask equipped with a stirring blade, a thermometer, and a condenser, 4.4 parts by weight of 1-butyl-3-methylpyridinium claloid (manufactured by Wako Pure Chemical Industries, Ltd.) was diluted to 20% by weight with distilled water. After adding the aqueous solution, a solution obtained by diluting 8 parts by weight of sodium lauryl sulfate (manufactured by Tokyo Chemical Industry Co., Ltd.) to 10% by weight with a mixed solution (weight ratio: acetone / distilled water = 1 / 1.25) while turning the stirring blade Slowly added. After the addition, stirring was continued at 25 ° 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 twice with 100 parts by weight of distilled water, then dried in an environment of 110 ° C. for 2 hours, and 2.5 weight of ionic liquid (1) which was liquid at 25 ° C. I got a part.

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 1-butyl-3-methylpyridinium lauryl sulfate.

<Preparation of antistatic agent solution>
[Antistatic agent solution (a)]
A four-necked flask equipped with a stirring blade, a thermometer and a condenser was charged with 10 parts by weight of lauryltrimethylammonium chloride (manufactured by Tokyo Chemical Industry Co., Ltd., solid at 25 ° C.), 20 parts by weight of ethyl acetate and 20 parts by weight of isopropyl alcohol. An antistatic agent solution (a) (20% by weight) was prepared by diluting with a mixed solvent consisting of parts.

<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). Thickness: 0.2 μm) to form an antistatic film.

[Example 1]
(Preparation of adhesive solution)
The acrylic polymer (A) solution (35% by weight) is diluted to 20% by weight with ethyl acetate. To 100 parts by weight of this solution is added 0.1 part by weight of the ionic liquid (1) and hexamethylene diisocyanate as a crosslinking agent. 0.46 part by weight of an isocyanurate body (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) and 0.4 part by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst were added at 25 ° C. for about 1 minute. Mixing and stirring were performed to prepare an acrylic pressure-sensitive adhesive solution (1).

(Creation 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 a silicone treatment on one side was bonded to the surface of the pressure-sensitive adhesive layer to produce a pressure-sensitive adhesive sheet.

[Comparative Example 1]
(Preparation of adhesive solution)
An acrylic pressure-sensitive adhesive solution (2) was prepared in the same manner as in Example 1 except that the ionic liquid (1) was not 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 (2) was used instead of the acrylic pressure-sensitive adhesive solution (1).

[Comparative Example 2]
(Preparation of adhesive solution)
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 to 0.5 parts by weight of the antistatic agent solution (a) (20% by weight), Add 0.46 parts by weight of isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., Coronate HX) as a crosslinking agent, and add 0.4 parts by weight of dibutyltin dilaurate (1% by weight ethyl acetate solution) as a crosslinking catalyst. An acrylic pressure-sensitive adhesive solution (3) was prepared by mixing and stirring at about 1 minute for about 1 minute.

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

  About the adhesive sheet obtained by said Example and comparative example, the measurement of the peeling band voltage, evaluation of a contamination property, and the measurement of adhesive force were performed in the following ways.

<Measurement of peeling voltage>
The pressure-sensitive adhesive sheet was cut to a size of 70 mm in width and 130 mm in length, the separator was peeled off, and then the acrylic plate (Mitsubishi Rayon Co., Acrylite, thickness: 1 mm, width: 70 mm, length: 100 mm, which had been previously neutralized. ) Was bonded to the surface of the polarizing plate (manufactured by Nitto Denko Corporation, SEG1425AGS2B, width: 70 mm, length: 100 mm) with a hand roller so that one end protruded 30 mm.

  After being left for one day in an environment of 23 ° C. × 50% RH, the sample was set at a predetermined position as shown in FIG. One end protruding 30 mm was fixed to an automatic winder, and peeled so that the peeling angle was 150 ° and the peeling speed was 10 m / min. 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 the center position in the length direction of the sample. The measurement was performed in an environment of 20 ° C. × 50% RH.

<Evaluation of contamination>
After the measurement of the stripping voltage, the peeled adhesive sheet was again attached by hand so that bubbles were mixed between the measured polarizing plate and an evaluation sample was prepared.

The evaluation sample was allowed to stand in an environment of 23 ° C. × 50% RH for 1 month, and then the pressure-sensitive adhesive sheet was peeled off from the adherend by hand, and the state of contamination on the adherend surface at that time was visually observed. . The evaluation criteria are as follows.
・ If no contamination was found: ○
・ If contamination is found: ×

<Measurement of adhesive strength>
A triacetyl cellulose film (Fuji Photo Film Co., Ltd., Fujitack, thickness: 80 μm) is cut into a width of 70 mm and a length of 100 mm, immersed in a 60 ° C. sodium hydroxide aqueous solution (10% by weight) for 1 minute, and then in distilled water. To prepare an adherend.

  The above adherend was allowed to stand in an environment of 23 ° C. × 50% RH for 1 day, and then an adhesive sheet cut to a width of 25 mm and a length of 100 mm was laminated on 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.

  The results are shown in Table 1.

  As is clear from the results in Table 1 above, when the pressure-sensitive adhesive composition prepared according to the present invention was used (Example 1), the absolute value of the peeling band voltage to the polarizing plate was as low as 0.5 kV or less. It was clarified that there was no contamination to the polarizing plate.

  On the other hand, when the pressure-sensitive adhesive composition containing no ionic liquid was used (Comparative Example 1), the result was that the stripping voltage to the polarizing plate was high. Further, when a conventional surfactant was used as the antistatic agent (Comparative Example 1), although the stripping voltage was suppressed, the occurrence of contamination was observed. Therefore, in any of the pressure-sensitive adhesive sheets of Comparative Examples 1 and 2, it is impossible to side-by-side suppress the stripping voltage to the polarizing plate and to suppress the contamination to the adherend, and for the antistatic pressure-sensitive adhesive sheet. It became clear that it was not suitable for an adhesive composition.

  Further, the pressure-sensitive adhesive sheet of Example 1 of the present invention has a 180 ° peel adhesive strength at a peeling speed of 10 m / min in the range of 0.1 to 6 N / 25 mm, and can be applied as a re-peelable surface protective film. It turns out that it is an adhesive sheet.

  Therefore, it can be confirmed that the pressure-sensitive adhesive composition of the present invention is a pressure-sensitive adhesive composition having excellent adhesion reliability, having excellent antistatic properties when peeled and having reduced contamination to an adherend. It was.

Claims (6)

(Meth) acrylic based on ionic liquid and base polymer having glass transition temperature (Tg) of 0 ° C. or lower and having (meth) acrylate having 1 to 14 carbon atoms as alkyl group a pressure-sensitive adhesive composition comprising a polymer, an anionic component of the ionic liquid is a sulfate ester anion,
The pressure-sensitive adhesive composition, wherein the ionic liquid contains one or more cations represented by the following general formulas (A), (C), and (D) .

[R _a in the formula (A) represents a hydrocarbon group having 4 to 20 carbon atoms and may include a hetero atom, and R _b and R _c may be the same or different, and may be hydrogen or _C 1 to _C 16. Represents a hydrocarbon group and may contain heteroatoms. However, when the nitrogen atom contains a double bond, there is no R _c . ]
[R _h in the formula (C) represents a hydrocarbon group having 2 to 20 carbon atoms, and may contain a hetero atom, and R _i , R _j , and R _k may be the same or different and represent hydrogen or carbon number. Represents 1 to 16 hydrocarbon groups and may contain heteroatoms. ]
[Z in Formula (D) represents a nitrogen, sulfur, or phosphorus atom, and R ₁ , R _m , R _n , and R _o are the same or different and represent a hydrocarbon group having 1 to 20 carbon atoms. And may contain heteroatoms. However, when Z is a sulfur atom, there is no _Ro . ] The pressure-sensitive adhesive composition according to claim 1, wherein the polymer is a polymer having an ether group-containing monomer as a monomer component. Pressure-sensitive adhesive layer obtained by crosslinking a pressure-sensitive adhesive composition according to claim 1 or 2. A pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition according to claim 1 or 2 formed on one side or both sides of a support. A surface obtained by forming a pressure-sensitive adhesive layer obtained by crosslinking the pressure-sensitive adhesive composition according to claim 1 or 2 on one side or both sides of a support made of a plastic substrate subjected to antistatic treatment. Protective film. The optical member which bonded the surface protection film of Claim 5.

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