Antistatic agents and antistatic resin compositions

Abstract

The present invention provides an antistatic agent that exhibits excellent antistatic properties and can reduce defects in molded products and coatings. [Solution] An antistatic agent is used that is an ionic compound consisting of a cation (A) and an anion (B), has a melting point of 25 to 180°C, a water content of 0.5% or less, and a halide ion content of 1000 ppm or less, and an antistatic resin composition containing the above antistatic agent and a thermoplastic resin, preferably in which the cation (A) is a quaternary ammonium cation and / or an amidinium cation.

Description

Technical Field

[0001] The present invention relates to an antistatic agent and an antistatic resin composition.

Background Art

[0002] Conventionally, as a method for imparting antistatic properties to a resin, a method of blending an antistatic agent is known. Among them, ionic liquids are widely used because they have high conductivity, excellent antistatic properties, and excellent compatibility. In particular, ionic liquids with excellent conductivity often contain fluorine atoms in anions such as trifluoromethanesulfonyl imide. This is because the strong electron-withdrawing effect of halogen delocalizes the negative charge, thereby lowering the viscosity of the system and increasing the conductivity. Therefore, many ionic liquids for applications that emphasize conductivity contain fluorine atoms (Patent Document 1). However, anions containing fluorine may decompose under the influence of heat or the like and generate hydrogen fluoride. Since hydrogen fluoride corrodes metals such as resin molding equipment, an ionic liquid that can exhibit antistatic properties without containing fluorine atoms as much as possible is desirable. In addition, perfluorocarbons are very difficult to decompose in the environment and continue to remain in the environment for a long time, resulting in a high environmental burden. Therefore, depending on the structure, some are subject to legal regulations. From this point of view as well, an ionic liquid containing as few fluorine atoms as possible is desirable. In Cited Document 2, an antistatic agent containing no halogen has been proposed, but the finish of the molded product is not sufficient and there is room for improvement.

Prior Art Documents

Patent Documents

[0003] [[ID=2H]]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] This invention has been made in view of the above-mentioned problems, and the object of this invention is to provide an antistatic agent that has excellent antistatic properties and can reduce defects in molded products and coatings. [Means for solving the problem]

[0005] The inventors of this invention arrived at this present invention as a result of diligent research to solve these problems. In other words, the present invention relates to an antistatic agent comprising an ionic compound consisting of a cation (A) and an anion (B), having a melting point of 25 to 180°C, a water content of 0.5% or less, and a halide ion content of 1000 ppm or less; and an antistatic resin composition containing the above antistatic agent and a thermoplastic resin. [Effects of the Invention]

[0006] The present invention makes it possible to provide an antistatic agent that exhibits excellent antistatic properties and can reduce defects in molded products and coatings. [Modes for carrying out the invention]

[0007] The present invention will be described in detail below.

[0008] The antistatic agent of the present invention is an ionic compound comprising a cation (A) and an anion (B), having a melting point of 25 to 180°C, a water content of 0.5% or less, and a halide ion content of 1000 ppm or less.

[0009] The cation (A) is not particularly limited, and any known cation can be used, such as amidinium cation, phosphonium cation, and quaternary ammonium cation.

[0010] Amidinium cations include imidazolinium cations and imidazolium cations. Examples of imidazolinium cations include 1,2,3,4-tetramethylimidazolinium, 1,3,4-trimethyl-2-ethylimidazolinium, 1,3-dimethyl-2,4-diethylimidazolinium, 1,2-dimethyl-3,4-diethylimidazolinium, 1-methyl-2,3,4-triethylimidazolinium, 1,2,3,4-tetraethylimidazolinium, 1,2,3-trimethylimidazolinium, 1,3-dimethyl-2-ethylimidazolinium, 1-ethyl-2,3-dimethylimidazolinium, 1,2,3-triethylimidazolinium, 4-cyano-1,2,3-trimethylimidazolinium, 3-cyanomethyl-1,2-dimethylimidazolinium, and 2-cyanomethyl-1,3-dimethylimidazolinium. Examples of cations include 4-acetyl-1,2,3-trimethylimidazolinium, 3-acetylmethyl-1,2-dimethylimidazolinium, 4-methylcarboxymethyl-1,2,3-trimethylimidazolinium, 3-methylcarboxymethyl-1,2-dimethylimidazolinium, 4-methoxy-1,2,3-trimethylimidazolinium, 3-methoxymethyl-1,2-dimethylimidazolinium, 4-formyl-1,2,3-trimethylimidazolinium, 3-formylmethyl-1,2-dimethylimidazolinium, 3-hydroxyethyl-1,2-dimethylimidazolinium, 4-hydroxymethyl-1,2,3-trimethylimidazolinium, and 2-hydroxyethyl-1,3-dimethylimidazolinium. Examples of imidazolium cations include 1,3-dimethylimidazolium, 1,3-diethylimidazolium, 1-ethyl-3-methylimidazolium, 1,2,3-trimethylimidazolium, 1,2,3,4-tetramethylimidazolium, 1,3-dimethyl-2-ethylimidazolium, 1-ethyl-2,3-dimethylimidazolium, 1,2,3-triethylimidazolium, 1,2,3,4-tetraethylimidazolium, 1,3-dimethyl-2-phenylimidazolium, 1,3-dimethyl-2-benzylimidazolium, 1-benzyl-2,3-dimethylimidazolium, 4-cyano-1,2,3-trimethylimidazolium, 3-cyanomethyl-1,2-dimethylimidazolium, and 2-cyanomethyl-1,3-di Examples of cations include methylimidazolium, 4-acetyl-1,2,3-trimethylimidazolium, 3-acetylmethyl-1,2-dimethylimidazolium, 4-methylcarboxymethyl-1,2,3-trimethylimidazolium, 3-methylcarboxymethyl-1,2-dimethylimidazolium, 4-methoxy-1,2,3-trimethylimidazolium, 3-methoxymethyl-1,2-dimethylimidazolium, 4-formyl-1,2,3-trimethylimidazolium, 3-formylmethyl-1,2-dimethylimidazolium, 3-hydroxyethyl-1,2-dimethylimidazolium, 4-hydroxymethyl-1,2,3-trimethylimidazolium, and 2-hydroxyethyl-1,3-dimethylimidazolium.

[0011] Examples of phosphonium cations include tetraalkylphosphonium cations having an alkyl group with 1 to 4 carbon atoms (such as tetramethylphosphonium, tetraethylphosphonium, and triethylmethylphosphonium cations).

[0012] Examples of quaternary ammonium cations include cations represented by the following general formula (1).

[0013] [ka] [In general formula (1), R1 to R4 each independently represent a linear or branched alkyl group having 1 to 10 carbon atoms.] Examples of R1 to R4 include linear alkyl groups having 1 to 10 carbon atoms (methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, octyl group, nonyl group, and decyl group, etc.) and branched alkyl groups having 1 to 10 carbon atoms (isopropyl group, isobutyl group, sec-butyl group, tert-butyl group, etc.), with linear alkyl groups having 1 to 10 carbon atoms being preferred. Specific examples of the above general formula (1) include tetramethylammonium, tetraethylammonium, tetrabutylammonium, tetradecylammonium, triethylmethylammonium, tributylmethylammonium, and dimethyldidecylammonium.

[0014] Of the above cations (A), preferred from the viewpoint of conductivity are quaternary ammonium cations and amidinium cations, more preferably at least one cation selected from the group consisting of imidazolinium cations, imidazolium cations and cations represented by general formula (1), even more preferably 1-ethyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation and dimethyldidecylammonium cation, and particularly preferably 1-ethyl-3-methylimidazolium cation and 1-butyl-3-methylimidazolium cation.

[0015] Anion (B) is not particularly limited and any known anion can be used, for example, an anion obtained by removing at least one proton from an acid that does not contain halogen atoms, as exemplified below. The anion may also be a mixture of two or more types.

[0016] [1] Examples of inorganic acids include sulfuric acid, phosphoric acid, and nitric acid. [2] Examples of carboxylic acids include monocarboxylic acids and polycarboxylic acids. Examples of monocarboxylic acids include aliphatic monocarboxylic acids having 1 to 30 carbon atoms [saturated monocarboxylic acids (formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, lauric acid, myristic acid, stearic acid, and behenic acid, etc.) and unsaturated monocarboxylic acids (acrylic acid, methacrylic acid, and oleic acid, etc.)], and aromatic monocarboxylic acids (benzoic acid, cinnamic acid, and naphthoic acid, etc.). Examples of polycarboxylic acids (divalent to tetravalent polycarboxylic acids) include aliphatic polycarboxylic acids [saturated polycarboxylic acids (oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid, etc.), unsaturated polycarboxylic acids (maleic acid, fumaric acid, and itaconic acid, etc.)], aromatic polycarboxylic acids [phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid, etc.], aliphatic oxycarboxylic acids [glycolic acid, lactic acid, and tartaric acid, etc.], and aromatic oxycarboxylic acids [salicylic acid and mandelic acid, etc.]. [3] Examples of sulfonic acids include alkyl sulfonic acid (RSO3H) and alkylbenzene sulfonic acid (RC6H4SO3H). [4] Examples of phosphoric acid include alkyl phosphate esters (ROPO3H2) and alkyl ether phosphate esters [RO(CH2CH2O)] n Examples include [PO3H2]. Among these halogen-free acids, from the viewpoint of thermal stability, carboxylic acids, sulfonic acids, and phosphoric acids are preferred, more preferably sulfonic acids, and particularly preferably alkylbenzene sulfonic acids.

[0017] Among the above anions (B), anions with a pKa of the conjugate acid of -10 to 5.5 are preferred from the viewpoints of conductivity and thermal stability. Specifically, acetic acid (pKa = 4.8), propionic acid (pKa = 4.9), formic acid (pKa = 3.7), butyric acid (pKa = 4.8), valeric acid (pKa = 4.8), glycolic acid (pKa = 3.8), lactic acid (pKa = 3.9), succinic acid (pKa = 4.2), adipic acid (pKa = 4.4), citric acid (pKa = 3.2), dodecylbenzenesulfonic acid (pKa = -0.5), etc. can be mentioned.

[0018] Preferred combinations of the above cations (A) and anions (B) include an imidazolinium cation and an anion of dodecylbenzenesulfonic acid, an imidazolium cation and an anion of dodecylbenzenesulfonic acid, and a dimethyldidecylammonium cation and an anion of dodecylbenzenesulfonic acid.

[0019] The content of the ionic compound composed of cation (A) and anion (B) in the antistatic agent of the present invention is preferably 98 to 100% by weight, more preferably 99 to 100% by weight.

[0020] The antistatic agent of the present invention has a melting point of 25 to 180°C, and is preferably 40 to 175°C, more preferably 50 to 170°C, from the viewpoints of conductivity and ease of kneading with a thermoplastic resin. If the melting point is lower than 25°C, kneading with a thermoplastic resin becomes difficult, and if it is higher than 180°C, the conductivity deteriorates. In addition, the melting point in the present invention shall be measured by differential scanning calorimetry (hereinafter referred to as DSC). Specifically, the sample is heated from -150°C to 220°C at 20°C / min, and the melting point can be determined from the heat quantity change with respect to the reference at that time. Examples of ionic compounds with melting points of 25 to 180°C include 1-ethyl-3-methylimidazolium dodecylbenzenesulfonate, 1-butyl-3-methylimidazolium dodecylbenzenesulfonate, 1,2,3,4-tetramethylimidazolinium dodecylbenzenesulfonate, dimethyldidecylammonium dodecylbenzenesulfonate, 1-ethyl-3-methylimidazolium methanesulfonate, 1-butyl-3-methylimidazolium methanesulfonate, 1,2,3,4-tetramethylimidazolinium methanesulfonate, and 1-ethyl-3-methylimidazolium p-toluenesulfonate.

[0021] The antistatic agent of the present invention has a moisture content of 0.5% or less. From the viewpoint of reducing volatile components, it is preferably 0.25% or less, and more preferably 0.1% or less. If the moisture content is greater than 0.5%, the appearance of the molded product when mixed with resin will deteriorate. The moisture content in the present invention shall be measured by Karl Fischer titration.

[0022] Karl Fischer titration is performed by volumetric method, and methanol can be used as the solvent. Approximately 50 ml of methanol is placed in the titrator, and the methanol is made anhydrous with Karl Fischer titration solution. Then, the sample to be measured is quickly placed in the titrator, and the amount of titration required to make it anhydrous again with Karl Fischer titration solution, the mass of the sample to be measured, and the titer of the Karl Fischer titration solution are used to calculate the water content using the following formula. Water content (%)=(A×f) / (B×10) A: Volume (ml) of Karl Fischer titration solution used for titrating the sample. f: Titer of Karl Fischer titration solution (mgH2O / ml) B: Sample mass (g)

[0023] The antistatic agent of the present invention has a halide ion content of 1000 ppm or less. From the viewpoint of corrosion prevention, it is preferably 100 ppm or less, and more preferably 1 ppm or less. If the halide ion content is 1000 ppm or less, metal corrosion can be suppressed. Therefore, it can be used on materials that come into contact with metals. Unless intentionally added, halogens are mainly present in the raw materials used when synthesizing anions (B) and when halide salts are used for cations (A). If the halide ion content is higher than 1000 ppm, the halide ion content can be reduced by dissolving it in acetone or the like and then passing it through a column packed with alumina, for example.

[0024] In the present invention, the halide ion content of the antistatic agent can be determined by diluting the antistatic agent 100 to 10 times with ultrapure water, performing ion chromatography under the following conditions to determine the content of various halide ions, and then calculating the sum of the obtained content of various halide ions. Equipment: Ion chromatograph (Thermo Fisher SCIENTIFIC: Dionex ICS-5000+DC) Column: IonPac AS-22 + IonPac AG-22 Suppressor: AERS 4mm Solvent: Mixed solution of 4.5 mM sodium carbonate and 1 mM sodium bicarbonate. Standard sample: Anion mixed standard solution IV (Kanto Chemical) Measurement temperature: 35℃ Flow rate: 1.2mL / min

[0025] The antistatic agent of the present invention preferably has a conductivity of 0.1 to 50 mS / cm at 40°C, more preferably 1 to 40 mS / cm, and more preferably 3 to 30 mS / cm, from the viewpoint of antistatic properties. The conductivity referred to herein is the conductivity of a 10 wt% methanol solution of the antistatic agent, and the conductivity can be measured using an electrical conductivity meter.

[0026] In the present invention, a preferred method for producing an ionic compound consisting of a cation (A) and an anion (B) when cation (A) is a quaternary ammonium cation is exemplified below.

[0027] Manufacturing method A tertiary amine (the tertiary amine before the formation of a quaternary ammonium cation) is reacted with an equivalent or greater amount (e.g., 1.1 to 5.0 equivalents) of a dialkyl carbonate ester (e.g., dimethyl carbonate, diethyl carbonate) in or without a solvent (e.g., methanol) at a reaction temperature of 80 to 200°C, preferably 100 to 150°C, to form a quaternary ammonium salt. Then, an acid that forms the aforementioned anion is added (0.9 to 1.0 equivalents based on the equivalent amount of the quaternary ammonium cation), and the mixture is stirred at 10 to 50°C for 1 hour to exchange the salt. The solvent and water are removed by distillation at 80 to 180°C (preferably 140 to 180°C) under reduced pressure (preferably 0.1 to 10 kPa) to obtain the desired quaternary ammonium salt.

[0028] When cation (A) is an amidinium cation, tertiary amines such as 1,2-dimethylimidazole, 1-methylimidazole, and 1-ethylimidazole are used.

[0029] The antistatic resin composition of the present invention is a composition comprising the above-mentioned antistatic agent and a thermoplastic resin. Examples of thermoplastic resins include polyphenylene ether resin (PPE), polyolefin resins [polypropylene (PP), polyethylene (PE), ethylene-vinyl acetate copolymer resin (EVA), and ethylene-ethyl acrylate copolymer resin, etc.], poly(meth)acrylic resins [polymethyl methacrylate, etc.], and polystyrene resins [polymers comprising vinyl group-containing aromatic hydrocarbons alone, and vinyl group-containing aromatic hydrocarbons and one or more selected from the group consisting of (meth)acrylic acid esters, (meth)acrylonitrile, and butadiene as constituent units; for example, polystyrene (PS), styrene / acrylonitrile copolymer (AN resin), acrylonitrile / butadiene / styrene copolymer (ABS resin)]. Examples include [methyl methacrylate / butadiene / styrene copolymer (MBS resin) and styrene / methyl methacrylate copolymer (MS resin), etc.], polyester resins [polyethylene terephthalate, polybutylene terephthalate, polycyclohexanedimethylene terephthalate, polybutylene adipate and polyethylene adipate], polyamide resins [nylon 66, nylon 69, nylon 612, nylon 6, nylon 11, nylon 12, nylon 46, nylon 6 / 66 and nylon 6 / 12, etc.], polycarbonate resins [polycarbonate and polycarbonate / ABS alloy resin (PC / ABS), etc.], polyacetal resins, and mixtures of two or more of these. Of the above, polyphenylene ether resin, poly(meth)acrylic resin, polystyrene resin, acrylonitrile / butadiene / styrene copolymer (ABS resin), and polycarbonate resin are preferred from the viewpoint of the mechanical properties of the molded product described later and the dispersibility of the antistatic agent in the thermoplastic resin.

[0030] The content of the antistatic agent in the antistatic resin composition is preferably 0.5 to 5% by weight, and more preferably 1 to 3% by weight, based on the weight of the thermoplastic resin, from the viewpoint of the antistatic properties and mechanical properties of the molded article.

[0031] The antistatic resin composition of the present invention may contain other additives, to the extent that they do not impair the effects of the present invention. Examples of additives include colorants, mold release agents, antioxidants, flame retardants, ultraviolet absorbers, antibacterial agents, dispersants, and fillers. Two or more additives may be used in combination.

[0032] Examples of colorants include inorganic pigments (white pigments, cobalt compounds, iron compounds, and sulfides, etc.), organic pigments (azo pigments and polycyclic pigments, etc.), and dyes (azo, indigoid, sulfide, alizarin, acridine, thiazole, nitro, and aniline dyes, etc.).

[0033] Examples of mold release agents include alkyl (1-4 carbon) esters of fatty acids with 12-18 carbon atoms (such as butyl stearate), glycol (2-8 carbon) esters of fatty acids with 2-18 carbon atoms (such as ethylene glycol monostearate), polyhydric (trihydric or higher) alcohol esters of fatty acids with 2-18 carbon atoms (such as hydrogenated castor oil), and liquid paraffin.

[0034] Examples of antioxidants include phenol compounds [monocyclic phenols (e.g., 2,6-di-t-butyl-p-cresol), bisphenols [e.g., 2,2'-methylenebis(4-methyl-6-t-butylphenol)] and polycyclic phenols [e.g., 1,3,5-trimethyl-2,4,6-tris(3,5-di-t-butyl-4-hydroxybenzyl)benzene]], sulfur compounds (e.g., dilauryl-3,3'-thiodipropionate), phosphorus compounds (e.g., triphenylphosphite), and amine compounds (e.g., octylated diphenylamine).

[0035] Examples of flame retardants include halogen-containing flame retardants, nitrogen-containing flame retardants, sulfur-containing flame retardants, silicon-containing flame retardants, and phosphorus-containing flame retardants.

[0036] Examples of UV absorbers include benzotriazoles [such as 2-(2'-hydroxy-5'-methylphenyl)benzotriazole], benzophenones (such as 2-hydroxy-4-methoxybenzophenone), salicylates (such as phenyl salicylate), and acrylates (such as 2-ethylhexyl-2-cyano-3,3'-diphenylacrylate).

[0037] Examples of antibacterial agents include benzoic acid, sorbic acid, halogenated phenols, organic iodine, nitriles (such as 2,4,5,6-tetrachloroisophthalonitrile), thiocyanosides (such as methylenebisthianocyanate), N-haloalkylthioimides, copper compounds (such as 8-oxyquinoline copper), benzimidazole, benzothiazole, trihaloallyl, triazole, organic nitrogen sulfur compounds (such as Slaoff 39), quaternary ammonium compounds, and pyridine compounds.

[0038] Examples of dispersants include modified vinyl polymers having one or more functional groups (polar groups) selected from the group consisting of carboxyl groups, epoxy groups, amino groups, hydroxyl groups, and polyoxyalkylene groups (for example, polymers described in Japanese Patent Publication No. 3-258850, modified vinyl polymers having sulfonic acid groups described in Japanese Patent Publication No. 6-345927, and block polymers having a polyolefin portion and an aromatic vinyl polymer portion).

[0039] Examples of fillers include inorganic fillers (calcium carbonate, talc, clay, etc.) and organic fillers (urea, calcium stearate, etc.).

[0040] The total weight content of additives in the thermoplastic resin is preferably 45% by weight or less, more preferably 0.001 to 40% by weight, and even more preferably 0.01 to 35% by weight, from the viewpoint of the mechanical properties of the molded article.

[0041] The antistatic resin composition of the present invention can be obtained by melt-mixing the antistatic agent, thermoplastic resin, and optionally additives of the present invention. As for the melt-mixing method, a method can generally be applied in which each component, in pellet or powder form, is mixed in a suitable mixer (such as a Henschel mixer), and then melt-mixed in an extruder to form pellets. There are no particular restrictions on the order in which each component is added during melt mixing, but for example, [1] A method in which an antistatic agent is melted and mixed, and then a thermoplastic resin and, if necessary, additives are added all at once and melted and mixed. [2] A method in which an antistatic agent is melted and mixed, then a portion of the thermoplastic resin is melted and mixed in advance to prepare a high-concentration composition of the antistatic agent (masterbatch resin composition), and then the remaining thermoplastic resin and additives as needed are melted and mixed (masterbatch method or master pellet method). These are some examples. In methods [1] and [2], the concentration of the antistatic agent in the masterbatch resin composition is preferably 1 to 20% by weight, and more preferably 2 to 15% by weight. Of the methods [1] and [2], method [2] is preferred from the viewpoint of efficiently dispersing the antistatic agent in the thermoplastic resin. [Examples]

[0042] The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited thereto. Hereinafter, unless otherwise specified, "parts" refers to parts by weight.

[0043] [Preparation of antistatic agent] <Comparative Example 1> 135 parts (1.5 moles) of dimethyl carbonate and 192 parts of methanol were added to a stirring autoclave and stirred until homogenized. 96 parts (1.0 mole) of 1-ethylimidazole were then added dropwise using a dropper funnel. The mixture was then stirred at 130°C for 40 hours to obtain a mixture containing 1-ethyl-3-methylimidazolium methyl carbonate salt, excess dimethyl carbonate, and methanol. The autoclave was then cooled to room temperature, and a solution of 326 parts (1.0 mole) of dodecylbenzenesulfonic acid (manufactured by Teika Co., Ltd.: Teika Power B121) dissolved in 200 parts of methanol was added dropwise over 1 hour using a dropper funnel. Carbon dioxide gas was generated from the inside as soon as the dropper addition began. Subsequently, the mixture was heated to 110°C under reduced pressure of 1.0 kPa while passing nitrogen gas through at a rate of 0.1 mL / min to remove the solvents dimethyl carbonate and methanol, yielding a pale yellow 1-ethyl-3-methylimidazolium dodecylbenzenesulfonate (melting point: 127°C).

[0044] <Example 1> 100 parts of the 1-ethyl-3-methylimidazolium dodecylbenzenesulfonate obtained in Comparative Example 1 were added to an autoclave, and the autoclave was purged with nitrogen. Then, the mixture was heated at 170°C for 5 hours under reduced pressure of 1.0 kPa while passing nitrogen gas at a rate of 0.1 mL / min to remove water adsorbed on the salt, yielding a pale yellow, low-water content 1-ethyl-3-methylimidazolium dodecylbenzenesulfonate (melting point: 121°C).

[0045] <Comparative Example 2> 135 parts (1.5 moles) of dimethyl carbonate and 192 parts of methanol were added to a stirring autoclave and stirred until homogenized. 312 parts (1.0 mole) of methyl di-n-decylamine were then added dropwise using a dropper funnel. The mixture was then reacted at 130°C for 40 hours to obtain a mixture containing dimethyldidecylammonium methyl carbonate salt, excess dimethyl carbonate, and methanol. The autoclave was then cooled to room temperature, and a solution of 326 parts (1.0 mole) of dodecylbenzenesulfonic acid dissolved in 200 parts of methanol was added dropwise over 1 hour using a dropper funnel. Carbon dioxide gas was generated from the inside as soon as the dropper addition began. Subsequently, the mixture was heated to 100°C under a reduced pressure of 1.0 kPa while passing nitrogen gas through at a rate of 0.1 mL / min to remove dimethyl carbonate and methanol, obtaining dimethyldidecylammonium dodecylbenzenesulfonate (melting point: 169°C).

[0046] <Example 2> 100 parts of the dimethyldidecylammonium dodecylbenzenesulfonate obtained in Comparative Example 2 were added to an autoclave, and the autoclave was purged with nitrogen. Then, while passing nitrogen gas at a rate of 0.1 mL / min, the autoclave was heated at 180°C under reduced pressure of 1.0 kPa for 3 hours to remove the water adsorbed on the salt, yielding a pale yellow low-water content dimethyldidecylammonium dodecylbenzenesulfonate (melting point: 170°C).

[0047] <Comparative Example 3> 312 parts (1.0 mol) of methyl di-n-decylamine and 300 parts of deionized water were charged into a stirring autoclave and homogenized. 55.6 parts (1.1 mol) of methyl chloride, filled in a dropping cylinder, was added dropwise while maintaining the autoclave temperature below 35°C, and the mixture was allowed to react for 3 hours after the end of the addition. Then, the pressure was reduced to 1.0 kPa to remove excess methyl chloride. Next, the pressure was returned to atmospheric pressure, and 1107 parts (1.0 mol) of a 30 wt% aqueous solution of lithium dodecylbenzenesulfonate was added dropwise, and the mixture was stirred at room temperature for 3 hours. The mixture was heated to 120°C under a reduced pressure of 1.0 kPa to remove the water solvent. The resulting viscous substance was washed with excess methanol, and the precipitated lithium chloride was removed by filtration. The resulting filtrate was heated to 180°C under a reduced pressure of 1.0 kPa to remove methanol, and dimethyldidecylammonium dodecylbenzenesulfonate (melting point: 169°C) was obtained.

[0048] The antistatic agents of Examples 1 and 2 and Comparative Examples 1 to 3 were evaluated for their water content, conductivity, and halide ion content by the following method, and their metal corrosiveness was assessed. The results are shown in Table 1.

[0049] [Table 1]

[0050] [Moisture content] The moisture content of the obtained antistatic agent was measured using a Karl Fischer moisture meter (HIRANUMA Co., Ltd.: AQV-300).

[0051] [conductivity] The conductivity of a 10 wt% methanol solution of an antistatic agent was measured at 40°C using an electrical conductivity meter CM-40S [manufactured by Toa Denpa Kogyo Co., Ltd.].

[0052] [Halogen ion content] The obtained antistatic agent was diluted 100-fold and 10-fold with ultrapure water, and the halide ion content of the samples was evaluated using the ion chromatography apparatus described below. Equipment: Ion chromatograph (Thermo Fisher SCIENTIFIC: Dionex ICS-5000+DC) Column: IonPac AS-22 + IonPac AG-22 Suppressor: ARES 4mm Solvent: Mixed solution of 4.5 mM sodium carbonate and 1 mM sodium bicarbonate. Standard sample: Anion mixed standard solution IV (Kanto Chemical) Measurement temperature: 35℃ Flow rate: 1.2mL / min

[0053] [Corrosive to metals] 100 parts of the obtained antistatic agent were mixed with 100 parts of methanol and 3 parts of deionized water, and the mixture was shaken uniformly to create the evaluation solution. Two test pieces made of SUS304 material (50 mm long, 20 mm wide, 0.3 mm thick) were placed in the solution, and the corrosion state of the test pieces was visually observed after 240 hours at 40°C. ○: There are absolutely no signs of metal corrosion on the surface. ×: Traces of metal corrosion are visible on the surface.

[0054] <Examples 3-5, Comparative Examples 4-6> According to the raw materials used in Table 2, the antistatic agent and thermoplastic resin were blended in a Henschel mixer for 3 minutes, and then melt-kneaded in a vented twin-screw extruder at 230°C under conditions of a rotation speed of 100 rpm and a residence time of 3 minutes to obtain each antistatic resin composition. For each of the obtained antistatic resin compositions, the antistatic properties (surface resistance) and the appearance of the molded product were evaluated using the following test methods. The results are shown in Table 2.

[0055] [Table 2]

[0056] The thermoplastic resins shown in Table 2 are as follows: ABS resin [Product name "Sebian-V320", manufactured by Daicel Polymer Co., Ltd.]

[0057] <Antistatic properties> For each resin composition, a flat plate test specimen (100 mm long, 100 mm wide, 2 mm thick) was prepared using an injection molding machine [product name "PS40E5ASE", Nissei Plastic Industrial Co., Ltd.] at a cylinder temperature of 260°C and a mold temperature of 80°C. The surface resistance (in Ω) of the flat plate test specimen was measured using an ultra-insulation meter "DSM-8103" [manufactured by Toa Denpa Kogyo Co., Ltd.] at 23°C and 45% RH humidity.

[0058] <Presence or absence of defects in molded products> For each resin composition, flat test pieces (100 mm long, 100 mm wide, 2 mm thick) were prepared using an injection molding machine [product name "PS40E5ASE", Nissei Plastic Industrial Co., Ltd.] at a cylinder temperature of 260°C and a mold temperature of 80°C, and the appearance of the test pieces (molded products) was evaluated visually. ○: The surface is smooth and free of defects. △: The surface is smooth, but there are defects inside. ×: The surface is uneven and shows defects.

[0059] The results in Table 1 show that Examples 1 and 2 are antistatic agents that can suppress metal corrosion. Furthermore, the results in Table 2 show that the antistatic agents in Examples 1 and 2 not only impart an antistatic effect to plastics but also maintain a good appearance during molding. [Industrial applicability]

[0060] The antistatic agent of the present invention can be used to prevent static electricity in thermoplastic resins, and is particularly suitable for applications where appearance and aesthetics are important. Furthermore, it is useful as an antistatic agent for electronic materials where metal corrosion must be prevented.

Claims

1. An antistatic agent comprising a cation (A) and an anion (B), having a melting point of 25 to 180°C, a water content of 0.5% or less, and a halide ion content of 1000 ppm or less.

2. The antistatic agent according to claim 1, wherein the cation (A) is a quaternary ammonium cation and / or an amidinium cation.

3. The antistatic agent according to claim 1, wherein the pKa of the conjugate acid of the anion (B) is -10 to 5.

5.

4. The antistatic agent according to claim 1, wherein the conductivity of a 10% by mass methanol solution of the antistatic agent at 40°C is 0.1 to 50 mS / cm.

5. An antistatic resin composition comprising an antistatic agent according to any one of claims 1 to 4 and a thermoplastic resin.

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