Antistatic agents and adhesive compositions

Abstract

To provide an antistatic agent, etc., having excellent resin compatibility and antistatic properties. [Solution] An antistatic agent comprising a salt represented by formula (1), an adhesive composition containing the same, and an antistatic resin. [Formula 1] TIFF2026067512000013.tif34168 (in formula (1), Q + R1 is a cation that does not contain a halogen atom, and R1 represents one of the following groups: a hydrocarbon group with 1 to 6 carbon atoms, a hydrogen atom, a nitro group, an amino group, a cyano group, a carbonyl group, a hydroxyl group, or an alkoxy group, which may be the same or different.

Description

[Technical Field]

[0001] The present invention relates to an antistatic agent using a salt comprising a cation that does not contain halogen atoms and an anion having a biscatecollate borate skeleton, as well as an adhesive composition and an antistatic resin containing the same. [Background technology]

[0002] One known method for imparting antistatic properties to insulating resins is to coat the surface of the resin substrate with a conductive coating containing an antistatic agent. Examples of such antistatic agents include electron conductive materials such as carbon black and ITO, but when used in adhesives using resins, there are problems with the hardness and transparency of the adhesive layer. As an antistatic agent that imparts conductivity while maintaining the transparency of the adhesive layer, ionic conductive materials using onium salts are known.

[0003] Other antistatic agents used in resins include solid conductive materials such as metal salts. (Patent Document 1)

[0004] Onium salts are attracting attention because they possess excellent properties such as non-volatility, flame retardancy, and high ionic conductivity, and their physical properties and functions can be designed in various ways. Due to these properties, onium salts are used as antistatic agents for various resins.

[0005] While ionic liquids containing fluorine anions, such as bistrifluoromethanesulfonylimide and bisfluorosulfonylimide, are commonly used to impart antistatic properties to adhesives and other materials using onium salts, perfluoroalkyl and polyfluoroalkyl compounds are less desirable from the perspective of recent PFAS regulations, and there is a need for antistatic agents that are not included in PFAS regulations. (Patent Documents 2 and 3)

[0006] While there are reports of halogen-free onium salts, such as dodecylbenzenesulfonic acid as an anion, used as an antistatic agent in halogen-free adhesives, their low antistatic performance limits their range of applications. (Patent Document 4) In addition, there are reports of antistatic agents for adhesive applications using bisoxalate borate, which consists of boron complex anions, but their applications are limited because they are susceptible to hydrolysis and have poor heat and humidity resistance. (Patent Documents 5, 6)

[0007] Furthermore, as onium salts using boron complex anions, onium salts having an anion with a biscatecollate borate skeleton have been shown as solvents for organic synthesis and for use in electrochemical cells, but have not been used as antistatic agents in adhesives. (Patent Document 7) [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Application Publication No. 6-128539 [Patent Document 2] Japanese Patent Publication No. 2005-290357 [Patent Document 3] Japanese Patent Publication No. 2013-064146 [Patent Document 4] Japanese Patent Publication No. 2023-034983 [Patent Document 5] Japanese Patent Publication No. 2019-108414 [Patent Document 6] Japanese Patent Publication No. 2020-007471 [Patent Document 7] Japanese Patent Publication No. 2002-187893 [Overview of the project] [Problems that the invention aims to solve]

[0009] Antistatic agents containing perfluoroalkyl groups have a significant environmental impact, leading to increasing regulations. Furthermore, the increasing sophistication of electronic components demands ionic conductive materials with higher antistatic performance. However, bistrifluoromethanesulfonylimide (TFSI) and bisfluorosulfonylimide (FSI) tend to have poor compatibility with resins and thus poor antistatic performance. Therefore, there is a need for high-performance ionic conductive materials that comply with PFAS regulations. As fluorine-free anions, there are dodecylbenzenesulfonate anions (DBS) and bisoxalate borate anions (BOB) composed of boron complex anions. However, the former tends to have poor compatibility with resins and poor antistatic performance, while the latter is susceptible to hydrolysis and has poor moisture and heat resistance. The present invention aims to provide an adhesive composition and an antistatic resin that have improved moisture and heat resistance and excellent antistatic performance compared to existing halogen-free ion conductive materials. [Means for solving the problem]

[0010] As a result of diligent research, the inventors have discovered that by using a salt consisting of a biscatecolate borate skeleton and a halogen-free cation among boron complex anions as an antistatic agent, an antistatic agent with excellent resin compatibility, antistatic performance, and moisture-heat resistance, as well as an adhesive composition with excellent transparency and low haze, and an antistatic resin, can be obtained, thus completing the present invention.

[0011] The present invention is as follows [1] to [6].

[0012] [1] An antistatic agent consisting of a salt represented by formula (1). [ka] (In formula (1), Q + R1 is a cation that does not contain a halogen atom, and R1 represents one of the following groups: a hydrocarbon group with 1 to 6 carbon atoms, a hydrogen atom, a nitro group, an amino group, a cyano group, a carbonyl group, a hydroxyl group, or an alkoxy group, which may be the same or different. [2] The above-mentioned Q + is the antistatic agent according to [1], which is any one of the cations of formulas (2) to (4).

Chemical formula

Chemical formula

Advantages of the Invention

[0013] The antistatic agent of the present invention, as a halogen-free ion conductive material, exhibits high resin compatibility, stability even in high-humidity and high-temperature environments, and can exhibit sufficient antistatic performance with only a small amount of addition. When the antistatic agent of the present invention is used in an adhesive composition, it is possible to form an adhesive layer with high humidity and heat resistance, excellent transparency, and low haze, making it suitable for use in surface protective films that protect the surfaces of optical components and electronic material components. [Modes for carrying out the invention]

[0014] The present invention will be described below. However, the present invention is not limited to the following embodiments.

[0015] [Antistatic agent] The antistatic agent of the present invention comprises a salt represented by formula (1). This salt consists of a halogen-free cation and an anion having a biscatecollate borate skeleton. [ka]

[0016] In formula (1), R1 represents one of the following: a hydrocarbon group having 1 to 6 carbon atoms, a hydrogen atom, a halogen group, a nitro group, an amino group, a cyano group, a carbonyl group, a hydroxyl group, or an alkoxy group, and these may be the same or different. From the viewpoint of balancing antistatic performance and resin compatibility, a hydrocarbon group having 1 to 4 carbon atoms or a hydrogen atom is preferred. Specifically, examples of anions include biscatecholate borate or bis(4-methylcatecholate)borate.

[0017] In formula (1), Q +The cation is a halogen atom-free cation, and specific examples of cations include metal cations such as lithium, sodium, potassium, rubidium, cesium, calcium, magnesium, strontium, barium, manganese, nickel, iron, copper, silver, gold, and zinc, as well as onium cations such as ammonium cations, phosphonium cations, sulfonium cations, piperidinium cations, pyrrolidinium cations, pyrazolium cations, pyrazolinium cations, morpholinium cations, pyridinium cations, and imidazolium cations. From the viewpoint of antistatic performance and resin compatibility, ammonium cations, pyridinium cations, and imidazolium cations are preferred.

[0018] In formula (1), Q + When is one of the ammonium cation, pyridinium cation, or imidazolium cation, it is represented by formulas (2) to (4). [ka]

[0019] In formulas (2) to (4), R2 to R4 may be the same or different hydrogen atoms, a C1-C12 alkyl group, a C1-C12 alkoxy group, or a hydroxyl group, and adjacent R2 groups may be linked to form a C2-C6 alkylene group. Furthermore, the alkyl group may be linear or branched.

[0020] Among the salts represented by formula (1), the antistatic agent of the present invention is preferably the salt of formula (5). [ka]

[0021] In formula (5), R1 represents any of the following: a hydrocarbon group having 1 to 6 carbon atoms, a hydrogen atom, a halogen group, a nitro group, an amino group, a cyano group, a carbonyl group, a hydroxyl group, or an alkoxy group, and these may be the same or different. R5 is a hydrocarbon group having 1 to 4 carbon atoms, and this hydrocarbon group may be linear or branched. Specifically, it is preferably a methyl group, an ethyl group, a propyl group, an isopropyl group, a cyclopropyl group, a butyl group, an s-butyl group, or a tert-butyl group, and most preferably a methyl group from the viewpoint of antistatic performance and resin compatibility. R6 is a hydrocarbon group having 2 to 12 carbon atoms, and this hydrocarbon group may be linear or branched. Specifically, examples include ethyl group, n-propyl group, isopropyl group, cyclopropyl group, n-butyl group, s-butyl group, tert-butyl group, n-pentyl group, cyclopentyl group, isopentyl group, neopentyl group, tert-pentyl group, n-hexyl group, cyclohexyl group, n-heptyl group, isohexyl group, 2-ethylhexyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, etc., and from the viewpoint of resin compatibility, preferred These are ethyl group, n-butyl group, s-butyl group, tert-butyl group, n-pentyl group, cyclopentyl group, isopentyl group, neopentyl group, tert-pentyl group, n-hexyl group, isohexyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-undecyl group, and n-dodecyl group. More preferably, from a balance between antistatic performance and resin compatibility, the group is ethyl group, n-butyl group, n-hexyl group, or n-octyl group.

[0022] In the present invention, it is preferable to use 1-methyl-3-ethylimidazolium=biscatecholate borate, 1-methyl-3-butylimidazolium=biscatecholate borate, 1-methyl-3-hexylimidazolium=biscatecholate borate, 1-methyl-3-octylimidazolium=biscatecholate borate, 1-methyl-3-ethylimidazolium=bis(4-methylcatecholate)borate, 1-methyl-3-butylimidazolium=bis(4-methylcatecholate)borate, 1-methyl-3-hexylimidazolium=bis(4-methylcatecholate)borate, or 1-methyl-3-octylimidazolium=bis(4-methylcatecholate)borate as the antistatic agent.

[0023] Q in equation (1) above + In the case of a metal salt using a metal cation, the salt can be a commercially available product or one synthesized by the method described in International Publication No. 94 / 027335, etc. For example, the cation may be replaced with a metal cation using a double decomposition reaction.

[0024] Q in equation (1) above + In the case of onium salts using onium cations, the target onium compound can be quaternized with alkyl halides to obtain onium halides, and then obtained by double decomposition with a metal salt having a biscatecollate borate skeleton. The compounds used in this reaction can be commercially available or synthesized by known methods.

[0025] In the case of the imidazolium salt represented by formula (5) above, it can be produced using known methods to obtain the above structure. Examples of such methods include the following. The compound used in this reaction can be a commercially available product or one synthesized by known methods. [Method for producing imidazolium salt] [ka] By quaternizing imidazoles represented by formula (6) with alkyl halides represented by formula (7), onium halides represented by formula (8) are obtained. In formulas (7) and (8), X is a halide. In formula (9), M + ∫ represents a metal ion. The double decomposition reaction of formulas (8) and (9) yields the (quaternary) onium salt represented by formula (5).

[0026] Examples of imidazoles of formula (6) include 1-methylimidazole, 1-ethylimidazole, 1-propylimidazole, 1-isopropylimidazole, and 1-butylimidazole.

[0027] Examples of alkyl halides in formula (7) include ethyl chloride, propyl chloride, butyl chloride, s-butyl chloride, tert-butyl chloride, cyclobutyl chloride, n-pentyl chloride, cyclopentyl chloride, isopentyl chloride, neopentyl chloride, tert-pentyl chloride, n-octyl chloride, isohexyl chloride, 2-ethylhexyl chloride, ethyl bromide, propyl bromide, isopropyl bromide, cyclopropyl bromide, butyl bromide, s-butyl bromide, tert-butyl bromide, cyclobutyl bromide, n-pentyl bromide, cyclopentyl bromide, isopentyl bromide, neopentyl bromide, tert-pentyl bromide, n-octyl bromide, and isohexyl Examples include bromide, 2-ethylhexyl bromide, ethyl iodide, propyl iodide, isopropyl iodide, cyclopropyl iodide, butyl iodide, s-butyl iodide, tert-butyl iodide, cyclobutyl iodide, n-pentyl iodide, cyclopentyl iodide, isopentyl iodide, neopentyl iodide, tert-pentyl iodide, n-octyl iodide, isohexyl iodide, 2-ethylhexyl iodide, n-nonyl chloride, n-nonyl bromide, n-nonyl iodide, n-decyl chloride, n-decyl bromide, n-decyl iodide, n-undecyl chloride, n-undecyl bromide, n-undecyl iodide, n-dodecyl chloride, n-dodecyl bromide, and n-dodecyl iodide.

[0028] The quaternization reaction of formula (6) by formula (7) may or may not be carried out with a solvent. The solvent is not particularly limited as long as it does not affect the reaction. Specifically, examples include acetonitrile, methanol, ethyl acetate, benzene, toluene, xylene, diethyl ether, tetrahydrofuran, 1,4-dioxane, etc., with acetonitrile being preferred.

[0029] The amount of formula (7) used should be 0.7 moles or more per mole of formula (6), preferably 0.9 to 1.5 moles.

[0030] The reaction temperature in the quaternization reaction is usually 25°C or higher, preferably 30-150°C, and particularly preferably 60-120°C.

[0031] Examples of metal salts of formula (9) include lithium biscatecholate borate, sodium biscatecholate borate, potassium biscatecholate borate, silver biscatecholate borate, lithium bis(4-methylcatecholate) borate, sodium bis(4-methylcatecholate) borate, potassium bis(4-methylcatecholate) borate, and silver bis(4-methylcatecholate) borate.

[0032] The amount of formula (9) used in the double decomposition reaction is usually 0.8 moles or more, preferably 0.9 to 1.8 moles, and more preferably 1.0 to 1.2 moles, per mole of formula (8).

[0033] The double decomposition reaction is usually carried out in a solvent. The solvent is not particularly limited as long as it does not affect the reaction. Specifically, examples include pure water, acetonitrile, ethyl acetate, benzene, toluene, xylene, diethyl ether, tetrahydrofuran, 1,4-dioxane, etc., with pure water and acetonitrile being preferred.

[0034] The mixing order of formulas (8), (9), and the solvent is not particularly limited; formula (9) may be added after mixing formula (8) and the solvent, or formula (8) may be added after mixing formula (9) and the solvent.

[0035] The reaction temperature in the double decomposition reaction is usually 10°C or higher, preferably 10 to 60°C, and particularly preferably 15 to 50°C.

[0036] To isolate formula (5) from the reaction solution after the reaction is complete, the solvent and the generated inorganic salt are removed from the reaction solution. If inorganic salt precipitates in the resulting reaction solution, the solution is filtered to remove the precipitated inorganic salt, and then formula (5) is isolated by combining appropriate unit operations such as concentration, filtration, and extraction. The isolated formula (5) can be used as an antistatic agent.

[0037] The antistatic agent of the present invention obtained in this way is halogen-free. Furthermore, the antistatic agent of the present invention composed of a combination of an imidazolium cation and an anion having a biscatecholato borate skeleton has a higher ionic conductivity and better compatibility and hydrophobicity with resins compared to the case where other salts are selected. Therefore, it is particularly excellent in conductivity and high heat and humidity resistance, and good antistatic performance can be obtained.

[0038] [Adhesive composition] By combining the antistatic agent of the present invention with an acrylic adhesive, an adhesive composition imparted with antistatic ability can be obtained. By incorporating this adhesive composition imparted with antistatic ability into a resin, an antistatic adhesive resin is obtained. This antistatic adhesive resin is excellent in antistatic properties, excellent in transparency, and has a low haze. Also, the heat and humidity resistance of this antistatic adhesive resin is improved. For example, when an imidazolium salt is used as the antistatic agent, the surface resistance value of the antistatic adhesive resin formed from the adhesive composition is 5.0×10 10 Ω or less, more preferably 1.0×10 10 Ω or less, the transparency is a transmittance of 90% or more, preferably 92% or more, and the haze value is 2.0% or less, preferably 1.5% or less. Also, when the heat and humidity resistance test of the antistatic adhesive resin is carried out, the surface resistance value after the test is 5.0×10 10 Ω or less, more preferably 1.0×10 10 Ω or less, the transparency is a transmittance of 90% or more, preferably 92% or more, and the haze value is 2.0% or less, preferably 1.5% or less. Note that the surface resistance value is a value measured by a resistivity meter, and the transmittance and haze value are values measured by a haze meter. The heat and humidity resistance test can be carried out by placing it under certain temperature and humidity conditions, and then the surface resistance value can be measured by a resistivity meter, and the transmittance and haze value can be measured by a haze meter. Therefore, the adhesive composition of the present invention comprises at least the above-mentioned salt and an acrylic adhesive. Note that adhesive inks prepared by dissolving the above-mentioned adhesive composition in a soluble organic solvent are included in the adhesive composition of the present invention. Furthermore, the antistatic adhesive resin of the present invention also includes adhesive sheets, adhesive films formed by coating the above-mentioned adhesive ink onto a substrate, and those peeled off from the substrate. The antistatic adhesive resin of the present invention is generally used as what is called an adhesive layer.

[0039] The acrylic adhesive in the present invention preferably contains an acrylic polymer mainly composed of an acrylate or methacrylate having an alkyl group with 1 to 14 carbon atoms. Specifically, examples include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl acrylate, and the like.

[0040] The mass-average molecular weight of the acrylic polymer is 100,000 to 5,000,000, preferably 200,000 to 4,000,000, and more preferably 300,000 to 3,000,000. If the mass-average molecular weight is less than 100,000, there is a problem that the cohesive force of the adhesive composition will be weak, and when an adhesive sheet is made by forming an adhesive layer on a substrate as an antistatic adhesive resin, there is a risk that the adhesive will peel off from the substrate when peeling the adhesive layer from the adherend. On the other hand, if it exceeds 5,000,000, the fluidity of the polymer may decrease, which may reduce the adhesive force to the adherend. The mass-average molecular weight can be measured by gel permeation chromatography (GPC).

[0041] Acrylic polymers can be obtained by common polymerization methods for acrylic polymers, such as solution polymerization, emulsion polymerization, bulk polymerization, and suspension polymerization, and may be random copolymers, block copolymers, graft copolymers, etc.

[0042] Furthermore, by appropriately crosslinking the acrylic polymer, an adhesive composition with a heat-resistant adhesive layer can be obtained. One method of crosslinking is to add a crosslinking agent to the acrylic adhesive. Examples of crosslinking agents include isocyanate compounds, epoxy compounds, aziridine compounds, and metal chelate compounds.

[0043] Isocyanate compounds are compounds having at least two isocyanate groups (-NCO) in their molecule. Specifically, examples 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 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate; and isocyanate adducts such as trimethylolpropane / tolylene diisocyanate trimer adducts, trimethylolpropane / hexamethylene diisocyanate trimer adducts, and isocyanurates of hexamethylene diisocyanate.

[0044] Epoxy compounds are compounds that have at least two epoxy groups in their molecule. Specifically, examples include bisphenol A type epoxy resins, ethylene glycol diglycidyl ether, glycerin diglycidyl ether, 1,6-hexanediol diglycidyl ether, and N,N-diglycidylaniline.

[0045] Aziridine compounds are compounds that have at least two three-membered ring skeletons, also known as ethyleneimines, consisting of one nitrogen atom and two carbon atoms, within their molecule. Specifically, examples include diphenylmethane-4,4'-bis(1-aziridinecarboxamide), toluene-2,4-bis(1-aziridinecarboxamide), triethylenemelamine, isophthaloylbis-1-(2-methylaziridine), tris-1-aziridinylphosphine oxide, hexamethylene-1,6-bis(1-aziridinecarboxamide), trimethylolpropane-tri-β-aziridinylpropionate, and tetramethylolmethane-tri-β-aziridinylpropionate.

[0046] Examples of metal chelate compounds include compounds in which acetylacetone or ethyl acetoethyl is coordinated to polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium.

[0047] The crosslinking agent content is preferably 0.01 to 10 parts by mass, and more preferably 0.1 to 5.0 parts by mass, per 100 parts by mass of the acrylic adhesive. If the content is less than 0.01 parts by mass, the crosslinking will be insufficient, resulting in a weak cohesive force of the adhesive composition and insufficient heat resistance. On the other hand, if the content exceeds 10 parts by mass, the polymer cohesive force will be too strong, reducing fluidity and resulting in insufficient wettability to the adherend, which can cause peeling.

[0048] The adhesive composition of the present invention may contain a surfactant comprising an alkylene oxide group-containing compound. An alkylene oxide group-containing compound is a compound having an alkylene oxide group, and specifically includes alkylene oxide group-containing surfactants, alkylene oxide group-containing polyether polymers, and alkylene glycol group-containing (meth)acrylic polymers. Among these, alkylene oxide group-containing surfactants are preferably used because they have good compatibility with acrylic polymers.

[0049] Examples of alkylene oxide group-containing surfactants include nonionic surfactants such as polyoxyalkylene fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, polyoxyalkylene sorbitol fatty acid esters, polyoxyalkylene alkyl ethers, polyoxyalkylene alkylallyl ethers, polyoxyalkylene alkylphenyl ethers, polyoxyalkylene derivatives, polyoxyalkylene alkylamines, and polyoxyalkylene alkylamine fatty acid esters; anionic surfactants such as polyoxyalkylene alkyl ether sulfates, polyoxyalkylene alkyl ether phosphates, polyoxyalkylene alkylphenyl ether sulfates, and polyoxyalkylene alkylphenyl ether phosphates; cationic surfactants and zwionic surfactants having alkylene oxide groups. Furthermore, the molecule may contain reactive substituents such as (meth)acryloyl groups and allyl groups.

[0050] The alkylene oxide group-containing compound may be used alone or as a mixture of two or more types. The amount added is preferably 0.01 to 10 parts by mass, and more preferably 0.05 to 5 parts by mass, per 100 parts by mass of the acrylic polymer. If the amount is less than 0.01 parts by mass, bleeding may occur.

[0051] Furthermore, the adhesive composition of the present invention may contain a silane compound. By including a silane compound, adhesion to substrates such as films and glass can be improved.

[0052] Examples of silane compounds include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, and 3-glycidoxypropylethoxydimethylsilane. Two or more of these may be used in combination.

[0053] The amount of the salt represented by formula (1) in the adhesive composition of the present invention is preferably 0.01 to 20 parts by mass, more preferably 0.1 to 10 parts by mass, and particularly preferably 0.5 to 5.0 parts by mass, per 100 parts by mass of the acrylic adhesive. By adjusting the amount within this range, an adhesive composition with even better electrical properties can be obtained. Furthermore, the adhesive composition of the present invention is not subject to PFAS regulations (halogen-free).

[0054] The adhesive composition of the present invention may be used in combination with other binder resins, antioxidants, ultraviolet absorbers, lubricants, etc., as long as the effects of the present invention are not impaired.

[0055] When producing an adhesive sheet with an adhesive layer formed on a substrate using an antistatic adhesive resin, the adhesive composition of the present invention may be applied directly to the substrate, or an adhesive ink prepared by dissolving the adhesive composition in a soluble organic solvent may be applied to the substrate. By applying these adhesive compositions or adhesive inks to substrates such as resin films and glass, and then drying them as necessary, an adhesive sheet with an adhesive layer formed on the surface of these substrates can be produced. The thickness of the adhesive layer is preferably 3 to 100 μm, and more preferably 5 to 50 μm.

[0056] [Adhesive ink] Organic solvents used in adhesive inks as adhesive compositions include alcohol-based solvents such as methanol, ethanol, propanol, isopropanol (IPA), and butanol; glycol-based solvents such as ethylene glycol, propylene glycol, butylene glycol, polyethylene glycol, polypropylene glycol, and polyoxyethylene polyoxypropylene copolymer; ether alcohol-based solvents such as monomethyl ether, monoethyl ether, monopropyl ether, monoisopropyl ether, and monobutyl ether of the glycol-based solvents; polyether-based solvents such as dimethyl ether, diethyl ether, dipropyl ether, diisopropyl ether, dibutyl ether, methyl ethyl ether, methyl propyl ether, methyl isopropyl ether, methyl butyl ether, ethyl propyl ether, ethyl isopropyl ether, and ethyl butyl ether of the glycol-based solvents; ketone-based solvents such as methyl ethyl ketone (MEK), methyl isobutyl ketone, and cyclohexanone; ester-based solvents such as methyl acetate, ethyl acetate, and butyl acetate; and hydrocarbon-based solvents such as hexane, heptane, octane, cyclopentane, cyclohexane, toluene, and xylene. Among these, toluene, MEK, ethyl acetate, butyl acetate, and IPA are particularly preferred.

[0057] [Base material] Examples of substrates include polyethylene terephthalate (PET) film, polycarbonate film, polystyrene film, acrylic film, cellulose triacetate film, polyethylene film, and polypropylene film.

[0058] [Method for making adhesive sheets] Methods for applying adhesive compositions to substrates include roll coating, gravure coating, reverse coating, die coating, and comma coating. When drying to remove the solvent from the liquid film applied to the substrate, it is preferable that the drying temperature be between 50°C and 150°C from the viewpoint of promoting the hardening of the liquid film.

[0059] To protect the adhesive surface, a separator can be attached to the surface of the adhesive layer as needed. Paper or plastic film can be used as the separator, and plastic film is preferred due to its excellent surface smoothness.

[0060] Examples of plastic films include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, polyethylene terephthalate film, polybutylene terephthalate film, and polyurethane film.

[0061] The adhesive composition of the present invention and the adhesive sheets (antistatic adhesive resin) produced using it can be used in plastic products and the like. In particular, they can be used as surface protection films to protect the surfaces of optical components such as polarizing plates, wave plates, optical compensation films, light diffusion sheets, and reflective sheets used in liquid crystal displays, as well as protective films for electronic materials and semiconductor components.

[0062] [Antistatic resin] As described above, the antistatic agent of the present invention, when combined with an acrylic adhesive, can yield an adhesive composition with antistatic properties. Naturally, by simply incorporating it into various resins, the resin can be made conductive and thus an antistatic resin. Examples of resins that can contain the antistatic agent of the present invention include, in addition to acrylic adhesives, synthetic resins such as polyethylene terephthalate, polypropylene, and polycarbonate, as well as various adhesives or release agents (silicone adhesives, urethane adhesives, rubber adhesives, silicone release agents, fluorine release agents, acrylic release agents, etc.). The performance of the antistatic resin of the present invention is the same as that of the adhesive layer (antistatic adhesive resin) described above. Furthermore, it is preferable that the resin does not fall under PFAS regulations and does not contain halogens.

[0063] The antistatic resin of the present invention can be manufactured in the same manner as conventional antistatic resins using known antistatic agents. If the resin is, for example, an acrylic adhesive, a synthetic resin such as polyethylene terephthalate, polypropylene, or polycarbonate, or various adhesives or release agents (silicone adhesives, urethane adhesives, rubber adhesives, silicone release agents, fluorine release agents, acrylic release agents, etc.), an antistatic resin can be obtained by mixing them. Furthermore, if an acrylic resin monomer is used as the raw material for the resin, the antistatic resin of the present invention can be obtained by preparing a solution containing the acrylic resin monomer and the antistatic agent of the present invention, adding a photopolymerization initiator to the solution, and irradiating the resin coated with this solution with ultraviolet light. [Examples]

[0064] The present invention will be described in detail below with reference to examples of the present invention, but the present invention is not limited in any way to these examples.

[0065] (Example 1) [Manufacturing of antistatic agents] 1-Methyl-3-ethylimidazolium biscatecollate borate was prepared as follows:

[0066] 8.21 g of 1-methylimidazole was mixed with 11.44 g of ethyl bromide and 20 g of acetonitrile, and the mixture was heated and stirred at 40°C for 5 hours. After removing the solvent by concentration, liquid-liquid extraction was carried out by adding pure water and hexane to remove unreacted ethyl bromide, and then the mixture was concentrated to obtain 18.34 g of 1-methyl-3-ethylimidazolium bromide (96% yield). 100 g of acetonitrile was added to the synthesized 18.34 g of 1-methyl-3-ethylimidazolium bromide and dissolved, then 25.47 g of lithium biscatecollate borate was added and the mixture was stirred for 2 hours. After removing the solvent by concentration and washing with dichloromethane and pure water, the mixture was concentrated again to obtain 27.27 g of 1-methyl-3-ethylimidazolium biscatecollate borate (84% yield). This was used directly as an antistatic agent.

[0067] [Preparation of adhesive ink] • Acrylic adhesive ((meth)acrylic polymer, Mw: 500,000, manufactured by Soken Chemical Co., Ltd., 1499M, non-volatile content 30%): 10g • Hardening agent (isocyanate compound, manufactured by Soken Chemical Co., Ltd., D-90, non-volatile content 0.85%): 0.1g • Antistatic agent (1-methyl-3-ethylimidazolium biscatecollate borate): 0.06g The above composition was diluted with MEK to a non-volatile content concentration of 25 parts by mass to prepare an adhesive ink.

[0068] (Example 2) An adhesive ink was prepared without any changes except that the onium salt of 1-methyl-3-butylimidazolium=biscatecollate borate was used instead of the onium salt of Example 1.

[0069] [Manufacturing of antistatic agents] 1-Methyl-3-butylimidazolium biscatecollate borate was prepared as follows:

[0070] 8.21 g of 1-methylimidazole was mixed with 14.39 g of butyl bromide and 20 g of acetonitrile, and the mixture was heated and stirred at 85°C for 5 hours. After removing the solvent by concentration, liquid-liquid extraction was carried out by adding pure water and hexane to remove unreacted butyl bromide, and then the mixture was concentrated to obtain 21.04 g of 1-methyl-3-butylimidazolium bromide (96% yield). 100 g of acetonitrile was added to the 21.04 g of synthesized 1-methyl-3-butylimidazolium bromide and dissolved, then 25.47 g of lithium biscatecollate borate was added and the mixture was stirred for 2 hours. After removing the solvent by concentration and washing with dichloromethane and pure water, the mixture was concentrated again to obtain 29.88 g of 1-methyl-3-butylimidazolium biscatecollate borate (85% yield). This was used directly as an antistatic agent.

[0071] (Example 3) An adhesive ink was prepared without any changes except that the onium salt of 1-methyl-3-hexylimidazolium=biscatecollate borate was used instead of the onium salt of Example 1.

[0072] [Manufacturing of antistatic agents] 1-Methyl-3-hexylimidazolium biscatecollate borate was prepared as follows:

[0073] 8.21 g of 1-methylimidazole was mixed with 17.33 g of hexyl bromide and 20 g of acetonitrile, and the mixture was heated and stirred at 85°C for 5 hours. After removing the solvent by concentration, liquid-liquid extraction was carried out by adding pure water and hexane to remove unreacted hexyl bromide, and then the mixture was concentrated to obtain 24.47 g of 1-methyl-3-hexylimidazolium bromide (99% yield). 100 g of acetonitrile was added to the 24.47 g of synthesized 1-methyl-3-hexylimidazolium bromide and dissolved, then 25.47 g of lithium biscatecollate borate was added and the mixture was stirred for 2 hours. After removing the solvent by concentration and washing with dichloromethane and pure water, the mixture was concentrated again to obtain 31.62 g of 1-methyl-3-hexylimidazolium biscatecollate borate (81% yield). This was used directly as an antistatic agent.

[0074] (Example 4) An adhesive ink was prepared without any changes except that the onium salt of 1-methyl-3-octylimidazolium=biscatecollate borate was used instead of the onium salt of Example 1.

[0075] [Manufacturing of antistatic agents] 1-Methyl-3-octylimidazolium=biscatecollateborate was prepared as follows:

[0076] 8.21 g of 1-methylimidazole was mixed with 20.28 g of octyl bromide and 20 g of acetonitrile, and the mixture was heated and stirred at 85°C for 5 hours. After removing the solvent by concentration, liquid-liquid extraction was carried out by adding pure water and hexane to remove unreacted octyl bromide, and then the mixture was concentrated to obtain 26.97 g of 1-methyl-3-octylimidazolium bromide (98% yield). 100 g of acetonitrile was added to the 26.97 g of synthesized 1-methyl-3-octylimidazolium bromide and dissolved, then 25.47 g of lithium biscatecollate borate was added and the mixture was stirred for 2 hours. After removing the solvent by concentration and washing with dichloromethane and pure water, the mixture was concentrated again to obtain 31.46 g of 1-methyl-3-octylimidazolium biscatecollate borate (76% yield). This was used directly as an antistatic agent.

[0077] (Example 5) An adhesive ink was prepared without any changes except that the onium salt of 1-methyl-3-ethylimidazolium=bis(4-methylcatecholate)borate was used instead of the onium salt of Example 1.

[0078] [Manufacturing of antistatic agents] 1-Methyl-3-ethylimidazolium=bis(4-methylcatecholate)borate was prepared as follows:

[0079] 8.21 g of 1-methylimidazole was mixed with 11.44 g of ethyl bromide and 20 g of acetonitrile, and the mixture was heated and stirred at 40°C for 5 hours. After removing the solvent by concentration, liquid-liquid extraction was carried out by adding pure water and hexane to remove unreacted ethyl bromide, and then the mixture was concentrated to obtain 18.34 g of 1-methyl-3-ethylimidazolium bromide (96% yield). 100 g of acetonitrile was added to the synthesized 18.34 g of 1-methyl-3-ethylimidazolium bromide and dissolved, then 28.53 g of lithium bis(4-methylcatecholate)borate was added and the mixture was stirred for 2 hours. After removing the solvent by concentration and washing with dichloromethane and pure water, the mixture was concentrated again to obtain 28.13 g of 1-methyl-3-ethylimidazolium bis(4-methylcatecholate)borate (80% yield). This was used directly as an antistatic agent.

[0080] (Example 6) An adhesive ink was prepared without any changes except that the onium salt of 1-methyl-3-octylimidazolium=bis(4-methylcatecholate)borate was used instead of the onium salt of Example 1.

[0081] [Manufacturing of antistatic agents] 1-Methyl-3-octylimidazolium=bis(4-methylcatecholate)borate was prepared as follows:

[0082] 8.21 g of 1-methylimidazole was mixed with 20.28 g of octyl bromide and 20 g of acetonitrile, and the mixture was heated and stirred at 85°C for 5 hours. After removing the solvent by concentration, liquid-liquid separation was carried out by adding pure water and hexane to remove unreacted octyl bromide, and then the mixture was concentrated to obtain 26.97 g of 1-methyl-3-octylimidazolium bromide (96% yield). 100 g of acetonitrile was added to the 26.97 g of synthesized 1-methyl-3-octylimidazolium bromide and dissolved, then 28.53 g of lithium bis(4-methylcatecholate)borate was added and the mixture was stirred for 2 hours. After removing the solvent by concentration and washing with dichloromethane and pure water, the mixture was concentrated again to obtain 28.69 g of 1-methyl-3-octylimidazolium-bis(4-methylcatecholate)borate (65% yield). This was used as an antistatic agent.

[0083] (Comparative Example 1) An adhesive ink was prepared without any changes except that the onium salt of tributylmethylammonium bistrifluoromethanesulfonylimide (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., product code 352-27751) was used instead of the onium salt of Example 1.

[0084] (Comparative Example 2) An adhesive ink was prepared without any changes except that the onium salt of 1-methyl-3-ethylimidazolium=bisoxalatoborate was used instead of the onium salt of Example 1.

[0085] [Manufacturing of antistatic agents] 1-Methyl-3-ethylimidazolium=bisoxalatoborate was prepared as follows:

[0086] 8.21 g of 1-methylimidazole was mixed with 11.44 g of ethyl bromide and 20 g of acetonitrile, and the mixture was heated and stirred at 40°C for 5 hours. After removing the solvent by concentration, liquid-liquid extraction was carried out by adding pure water and hexane to remove unreacted ethyl bromide, and then the mixture was concentrated to obtain 18.34 g of 1-methyl-3-ethylimidazolium bromide (99% yield). 100 g of acetonitrile was added to the synthesized 18.34 g of 1-methyl-3-ethylimidazolium bromide and dissolved, then 21.10 g of lithium bisoxalatoborate was added and the mixture was stirred for 2 hours. After removing the solvent by concentration and washing with dichloromethane and pure water, the mixture was concentrated again to obtain 21.74 g of 1-methyl-3-ethylimidazolium bisoxalatoborate (76% yield). This was used directly as an antistatic agent.

[0087] (Comparative Example 3) An adhesive ink was prepared without any changes except that the onium salt of 1-methyl-3-octylimidazolium=bisoxalatoborate was used instead of the onium salt of Example 1.

[0088] [Manufacturing of antistatic agents] 1-Methyl-3-octylimidazolium=bisoxalatoborate was prepared as follows:

[0089] 8.21 g of 1-methylimidazole was mixed with 20.28 g of octyl bromide and 20 g of acetonitrile, and the mixture was heated and stirred at 85°C for 5 hours. After removing the solvent by concentration, liquid-liquid extraction was carried out by adding pure water and hexane to remove unreacted octyl bromide, and then the mixture was concentrated to obtain 27.25 g of 1-methyl-3-octylimidazolium bromide (99% yield). 100 g of acetonitrile was added to the 27.25 g of synthesized 1-methyl-3-octylimidazolium bromide and dissolved, then 21.10 g of lithium bisoxalatoborate was added and the mixture was stirred for 2 hours. After removing the solvent by concentration and washing with dichloromethane and pure water, the mixture was concentrated again to obtain 32.17 g of 1-methyl-3-octylimidazolium bisoxalatoborate (85% yield). This was used directly as an antistatic agent.

[0090] [Coating conditions] A test specimen (adhesive film) was prepared by coating a PET film with adhesive ink using a bar coater to a thickness of approximately 25 μm after drying, and then drying it in a hot air dryer at 120°C for 3 minutes.

[0091] [Surface resistance measurement] Using the HighLester UP (manufactured by Mitsubishi Chemical Analytech Co., Ltd., product name "MCP-HT450"), the probe was pressed against the coated surface of the test specimen at a temperature of 23±2℃, humidity of 50±5%RH, and applied voltage of 100V, and the stable surface resistance value was measured after 30 seconds.

[0092] [Measurement of transmittance and haze value] The transmittance and haze of the adhesive layer side of the adhesive film after the separator was removed were measured using a haze meter (manufactured by Nippon Denshoku Industries Co., Ltd., product name "NDH5000").

[0093] [Heat and moisture resistance test] The prepared test specimens were placed in a constant temperature chamber at 60°C and 85% humidity for 500 hours, and the surface resistance, transmittance, and haze values ​​were compared before and after the test.

[0094] Table 1 shows the results before the humidity and heat resistance test for Examples 1-6 and Comparative Examples 1-3, and Table 2 shows the results after the humidity and heat resistance test.

[0095] [Table 1]

[0096] [Table 2]

[0097] As described above, the adhesive compositions of Examples 1 to 6 of the present invention maintain a sufficient surface resistance value (1 × 10⁻¹) even after the humid heat resistance test, making them suitable as antistatic adhesive films (antistatic adhesive resins). 10 It had a haze value of 1.5% or less and a transmittance of 90% or more, which are the standards for resin compatibility. On the other hand, Comparative Examples 1 and 2 did not meet the standard values ​​for haze value and transmittance, and Comparative Example 3's haze value and transmittance significantly exceeded the standard values ​​after the humid heat resistance test, indicating a lack of the performance required for an antistatic adhesive resin. In addition, the adhesive inks of Examples 1 to 6 are not included in the PFAS regulations and are halogen-free.

[0098] Comparing Examples 1 and 4 with Comparative Examples 2 and 3, it is believed that in Comparative Examples 2 and 3, the boron complex anion had low hydrophobicity and a structure that was susceptible to hydrolysis. As a result, hydrolysis occurred over time in the humid heat resistance test, leading to a decrease in resin compatibility and a deterioration in haze value and transmittance. Therefore, it is considered that a specific onium salt, including those in the embodiments of the present invention, would satisfy both surface resistance and resin compatibility and be effective. [Industrial applicability]

[0099] This invention can be used in surface protection films and the like to protect the surface of optical components.

Claims

1. An antistatic agent comprising a salt represented by formula (1). 【Chemistry 1】 (In formula (1), Q ＋ R is a cation that does not contain halogen atoms, １ (This represents one of the following: a hydrocarbon group having 1 to 6 carbon atoms, a hydrogen atom, a nitro group, an amino group, a cyano group, a carbonyl group, a hydroxyl group, or an alkoxy group; these may be the same or different.)

2. The aforementioned Q + The antistatic agent according to claim 1, wherein is one of the cations of formulas (2) to (4). 【Chemistry 2】 (In formulas (2) to (4), R ２ ~R ４ Each of the following groups may be the same or different: hydrogen, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a hydroxyl group. ２ Adjacent groups may be linked to form alkylene groups having 2 to 6 carbon atoms. Furthermore, the alkyl group may exhibit either a linear or branched chain structure.

3. An antistatic agent comprising a salt represented by formula (5). 【Transformation 3】 (In formula (5), R ５ represents a hydrocarbon group having 1 to 4 carbon atoms, and this hydrocarbon group represents either a straight chain or a branched chain. R ６ represents a hydrocarbon group having 2 to 12 carbon atoms, and this hydrocarbon group represents either a straight chain or a branched chain. R １ represents any one of a hydrocarbon group having 1 to 6 carbon atoms, a hydrogen atom, a nitro group, an amino group, a cyano group, a carbonyl group, a hydroxy group, and an alkoxy group, and they may be the same or different from each other.)

4. An antistatic resin characterized by containing the antistatic agent and resin described in claims 1 to 3.

5. An adhesive composition characterized by containing the antistatic agent and acrylic adhesive described in claims 1 to 3.

6. The adhesive composition according to claim 5, characterized in that it contains 0.1 to 10 parts by mass of an antistatic agent per 100 parts by mass of the resin component of the acrylic adhesive.

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