JP6218597B2 - Ink composition for ballpoint pen and ballpoint pen incorporating the same - Google Patents

Description

The present invention relates to an ink composition for ballpoint pens . Furthermore, regarding light and smooth writing is possible based ink composition for a ballpoint pen and a ballpoint pen with a built-in it.

Conventional inks for writing instruments are roughly classified into water-based inks using water as a solvent and oil-based inks using an organic solvent such as benzyl alcohol or phenyl glycol as a solvent.
The water used as the solvent has a high surface tension, and in water-based inks, the wettability with respect to the pen tip is poor and the ink dischargeability and lubricity are poor. It is necessary to adjust the surface tension by blending or to impart lubricity.
In addition, in the case of oil-based inks in which the solvent is an organic solvent, ink dischargeability is obtained, but the lubricity is poor, and therefore, it is necessary to add a lubricant or the like to improve the writing feeling (for example, Patent Documents 1 to 4). reference).

JP 2000-80317 A Japanese Examined Patent Publication No. 6-74395 Japanese Patent Laid-Open No. 5-331403 JP 7-196971 A

  As described above, it is usually necessary to add a phosphate ester-based surfactant, a fatty acid such as oleic acid, or a salt thereof in order to impart lubricity in both water-based ink and oil-based ink. However, when the surfactant or fatty acid is used in ballpoint pen ink, a salt that is hardly soluble in the solvent precipitates due to the reaction with metal ions eluted into the ink from the metal member at the tip of the tip with time. Since it becomes easy, there exists a possibility that the writing defect may be caused by the deposit being clogged up with the tip part of a chip.

The present invention relates to a ballpoint pen ink that can be written with a light and smooth writing feeling without using an additive, and a ballpoint pen using the same, by using a new solvent different from conventional water-based inks and oil-based inks. Is to provide.

The ink composition for a ballpoint pen according to the present invention requires that an ionic liquid which is liquid at 25 ° C. is applied as a main solvent of 50% by weight or more in the ink composition and contains a colorant.
Furthermore, the ionic liquid is a liquid at 0 ° C. , and the anions constituting the ionic liquid are halogen anions, sulfur anions, phosphorus anions, boron anions, fluorine anions, nitrogen oxide anions, carboxylic acids It is required to be either an anion.
Furthermore, the ball-point pen which incorporates the ink composition for ball-point pens in any one of the said is made into requirements.

Although the ionic liquid applied to the present invention is a liquid, it is non-volatile and thermally stable as compared with water and organic solvents, and has a small viscosity change with temperature and high lubricity. Therefore, the ink composition for a ballpoint pen can be written with a light and smooth writing feeling without blending additives as in conventional water-based inks and oil-based inks. In addition, since the polarity of the ionic liquid can be adjusted by a combination of a cation and an anion, the ionic liquid is excellent in solubility and dispersibility in colorants such as a wide range of water-soluble and oil-soluble dyes and pigments. Furthermore, the ionic liquid has anti-corrosion (rust prevention) properties and is highly soluble in metal ions (metal salts), so it dissolves metal ions generated from the metal member at the tip of the chip and adds additives. Since it is difficult for insoluble precipitates to be generated when mixed, a highly practical ballpoint pen that expresses good ejection properties and can form handwriting that is permanently light and smooth with no brushing or shading. Can be provided.

  An ionic liquid is an organic salt composed of only ions, which is a combination of a cation and an anion. The ionic liquid used in the ink composition for a writing instrument of the present invention may be an anhydrous ionic liquid or a hydrated ionic liquid that has absorbed moisture in the air, and is a liquid at room temperature (25 ° C.), in particular a liquid at 0 ° C. It is desirable that In other words, by lowering the melting point of the ionic liquid, the ink for writing instruments having the ionic liquid as the main solvent can exist as a liquid without using a co-solvent in the actual temperature range, and the fluidity can be secured. As a result, the ink discharge performance is not impaired.

  The cation and anion constituting the ionic liquid are not particularly limited. Examples of the cation include an ammonium cation, an imidazolium cation, a pyridinium cation, a pyrrolidinium cation, a piperidinium cation, a phosphonium cation, and a sulfonium cation. , Pyrrolinium cation, pyrazinium cation, triazolium cation, isoquinolinium cation, oxazolinium cation, thiazolinium cation, morpholinium cation, guanidinium cation, thiophenium cation, pyrimidinium cation , Piperazinium cation, triazinium cation, quinolinium cation, indolinium cation, quinoxalinium cation, isoxazolium cation, thiooxonium kathi Emissions, and the like cationic amino acids.

  Examples of the ammonium cation include an ammonium cation, an ammonium cation in which hydrogen bonded to nitrogen of the ammonium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, and a hydroxyl group, an ether group, or a carbonyl in the alkyl chain. Group, carboxyl group, alkenyl group, amino group, nitrile group, halogen group, aryl group and other ammonium cations such as, for example, 2-hydroxyethylammonium cation, (1,1-bis (hydroxymethyl) Propyl) ammonium cation, N, N-di (2-hydroxyethyl) ammonium cation, tris (2-hydroxyethyl) ammonium cation, tetramethylammonium cation, tetrabutylammonium cation, tetrapentylammo Cation, tetrahexylammonium cation, tetradecylammonium cation, N, N, N-trimethylethylammonium cation, N, N, N-trimethylpropylammonium cation, N, N, N-trimethylbutylammonium cation, N, N, N -Trimethylpentylammonium cation, N, N, N-trimethylhexylammonium cation, N, N, N-trimethylheptylammonium cation, N, N, N-trimethyloctylammonium cation, N, N, N-trimethyldecylammonium cation, N, N, N-trimethyldodecylammonium cation, N-ethyl-N, N-dimethylpropylammonium cation, N-ethyl-N, N-dimethylbutylammonium cation, N- Tyl-N, N-dimethylhexylammonium cation, N- (2-hydroxyethyl) trimethylammonium cation, N-ethyl-N- (2-hydroxyethyl) dimethylammonium cation, N-ethyl-N- (2-methoxyethyl) ) Dimethylammonium cation, N, N-diethyl-N- (2-methoxyethyl) methylammonium cation, N- (2-methoxyethyl) -N, N, N-trimethylammonium cation, N- (2-ethoxyethyl) -N, N, N-trimethylammonium cation, N- (2-propoxyethyl) -N, N, N-trimethylammonium cation, N- (2-methoxyethyl) -N, N-dimethylpropylammonium cation, N- (2-methoxyethyl) -N, N-dimethylbutyla Ammonium cation, trimethyl (1H, 1H, 2H, 2H-heptadecafluorodecyl) ammonium cation, trimethyl- (4-vinylbenzyl) ammonium cation, tributyl- (4-vinylbenzyl) ammonium cation, 2- (methacryloxy) ethyltrimethyl Ammonium cation, benzyldimethyl (octyl) -ammonium cation, N, N-dimethyl-N- (2-phenoxyethyl) -1-dodecylammonium cation and the like can be mentioned.

  Examples of the imidazolium cation include an imidazolium cation, an imidazolium cation in which hydrogen bonded to nitrogen of the imidazolium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, and a hydroxyl group in the alkyl group. Examples include an imidazolium cation containing a functional group such as an ether group, a carbonyl group, a carboxyl group, an alkenyl group, an amino group, a nitrile group, a halogen group, and an aryl group. For example, as an imidazolium cation having one substituent Includes 1-methylimidazolium cation, 1-ethylimidazolium cation, 1-butylimidazolium cation, 1-hexylimidazolium cation and the like. As the imidazolium cation having two substituents, 1,3- Dimethylimidazolium Catio 1-ethyl-3-methylimidazolium cation, 1-propyl-3-methylimidazolium cation, 1-butyl-3-methylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-octyl-3 -Methylimidazolium cation, 1-hexadecyl-3-methylimidazolium cation, 1-octadecyl-3-methylimidazolium cation, 1- (2-hydroxyethyl) -3-methylimidazolium cation, 1- (2-carboxy Ethyl) -3-methylimidazolium cation, 1-cyanopropyl-3-methylimidazolium cation, 1-ethyl-3-octylimidazolium cation, 1-methyl-3-propylimidazolium cation, 1-butyl-3- Methyl imidazolium cation 1-methyl-3-butylimidazolium cation, 1-methyl-3-pentylimidazolium cation, 1-hexyl-3-methylimidazolium cation, 1-heptyl-3-methylimidazolium cation, 1-methyl-3- Octylimidazolium cation, 1-decyl-3-methylimidazolium cation, 1-dodecyl-3-methylimidazolium cation, 1-ethyl-3-propylimidazolium cation, 1-butyl-3-ethylimidazolium cation, 1 -Octyl-3-propylimidazolium cation, 1-hexyl-3-vinylimidazolium cation, 1-allyl 3-methylimidazolium cation, 1-allyl-3-ethylimidazolium cation, 1-allyl-3-propyl imidazolium cation Rim cation, 1-a Ryl-3-butylimidazolim cations, 1-allyl-3-pentylimidazolim cations, 1-allyl-3-hexylimidazolim cations, 1-allyl-3-heptylimidazolim cations, 1-allyl-3-octyl Imidazolim cation, 1,3-diallylimidazolium cation, 1-methyl-3- (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl ) Imidazolium cation, 1-benzyl-3-methylimidazolium cation, 1-methoxyethyl-3-methylimidazolium cation, 1- (2- (2-methoxyethoxy) -ethyl) -3-methylimidazolium cation, etc. Examples of the imidazolium cation having three substituents include 1-ethyl-2,3-dimethylimidazolium Cation, 1,2-dimethyl-3-ethylimidazolium cation, 1-propyl-2,3-dimethylimidazolium cation, 1,2-dimethyl-3-propylimidazolium cation, 1-butyl-2,3-dimethyl Imidazolium cation, 1,2-dimethyl-3-butylimidazolium cation, 1-hexyl-2,3-dimethylimidazolium cation, 1,2-dimethyl-3-hexylimidazolium cation, 1,2-dimethyl-3 -Octylimidazolium cation, 1-ethyl-3,4-dimethylimidazolium cation, 1-isopropyl-2,3-dimethylimidazolium cation and the like can be mentioned.

Examples of the pyridinium cation include a pyridinium cation, a pyridinium cation in which hydrogen bonded to nitrogen of the pyridinium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, and a hydroxyl group, an ether group, a carbonyl in the alkyl chain. And pyridinium cations containing functional groups such as a group, a carboxyl group, an alkenyl group, an amino group, a nitrile group, a halogen group, and an aryl group, such as N-methylpyridinium cation, N-ethylpyridinium cation, and N-butyl. Pyridinium cation, N-propylpyridinium cation, N-hexylpyridinium cation, N-ethyl-3-methylpridium, N-butyl-4-methylpyridinium cation, N-butyl-3-methylpyridinium cation, N- (3- It can be given mud hydroxypropyl) pyridinium cation and the like.

  Examples of the pyrrolidinium cation include a pyrrolidinium cation, a pyrrolidinium cation in which hydrogen bonded to nitrogen of the pyrrolidinium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, and an alkyl chain thereof. Examples thereof include pyrrolidinium cations containing a functional group such as a hydroxyl group, an ether group, a carbonyl group, a carboxyl group, an alkenyl group, an amino group, a nitrile group, a halogen group, and an aryl group, such as N, N-dimethyl. Pyrrolidinium cation, N-ethyl-N-methylpyrrolidinium cation, N-methyl-N-propylpyrrolidinium cation, N-butyl-N-methylpyrrolidinium cation, N-methyl-N-pentylpyrrolidi Nium cation, N-hexyl-N-methylpyrrolidinium cation, N-methyl N-octylpyrrolidinium cation, N-decyl-N-methylpyrrolidinium cation, N-dodecyl-N-methylpyrrolidinium cation, N- (2-methoxyethyl) -N-methylpyrrolidinium cation, N -(2-ethoxyethyl) -N-methylpyrrolidinium cation, N- (2-propoxyethyl) -N-methylpyrrolidinium cation, N- (2-isopropoxyethyl) -N-methylpyrrolidinium cation N- (2-hydroxyethyl) -N-methylpyrrolidinium cation and the like.

  Examples of the piperidinium cation include a piperidinium cation, a piperidinium cation in which hydrogen bonded to nitrogen of the piperidinium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, and an alkyl chain thereof. Examples thereof include piperidinium cations containing a functional group such as a hydroxyl group, an ether group, a carbonyl group, a carboxyl group, an alkenyl group, an amino group, a nitrile group, a halogen group, and an aryl group. For example, N, N-dimethylpiperidi Nium cation, N-ethyl-N-methylpiperidinium cation, N-methyl-N-propylpiperidinium cation, N-butyl-N-methylpiperidinium cation, N-methyl-N-pentylpiperidinium cation N-hexyl-N-methylpiperidinium cation, N-methyl-N-o Tilpiperidinium cation, N-decyl-N-methylpiperidinium cation, N-dodecyl-N-methylpiperidinium cation, N- (2-methoxyethyl) -N-methylpiperidinium cation, N- ( 2-methoxyethyl) -N-ethylpiperidinium cation, N- (2-ethoxyethyl) -N-methylpiperidinium ion, N-methyl-N- (2-methoxyphenyl) piperidinium cation, N-methyl -N- (4-methoxyphenyl) piperidinium cation, N-ethyl-N- (2-methoxyphenyl) piperidinium cation, N-ethyl-N- (4-methoxyphenyl) piperidinium cation, N- (2-hydroxyethyl) -N-methylpiperidinium cation and the like can be mentioned.

  Examples of the phosphonium cation include a phosphonium cation, a phosphonium cation in which hydrogen bonded to nitrogen of the phosphonium cation is a linear or branched alkyl group having 1 to 18 carbon atoms and an aryl group, and a hydroxyl group or an ether in the alkyl chain. Group, carbonyl group, carboxyl group, alkenyl group, amino group, nitrile group, halogen group, aryl group, and the like include phosulonium cation, for example, tetramethylphosphonium cation, tetraethylphosphonium cation, tetrapropylphosphonium cation Tetrabutylphosphonium cation, triisobutylmethylphosphonium cation, tetrahexylphosphonium cation, tributyl-n-octylphosphonium cation, trihexylmetetradecylphospho Honium cation, tributyl (4-vinylbenzyl) phosphonium cation, tetraphenylphosphonium cation, triphenylmethylphosphonium cation, (2-cyanoethyl) trioctylphosphonium cation, 3- (triphenylphosphonio) propane-1-sulfonic acid cation And quaternary phosphonium cations such as (3-chloropropyl) trioctylphosphonium cation.

  Examples of the sulfonium cation include a sulfonium cation, a sulfonium cation in which hydrogen bonded to nitrogen of the sulfonium cation is a linear or branched alkyl group having 1 to 18 carbon atoms, an aryl group, and a hydroxyl group or ether in the alkyl chain. And sulfonium cations containing functional groups such as carbonyl group, carboxyl group, alkenyl group, amino group, nitrile group, halogen group, and aryl group, such as trimethylsulfonium cation, triethylsulfonium cation, tripropylsulfonium cation, and tributylsulfonium cation. There can be mentioned tertiary sulfonium cations such as cations and triphenylsulfonium cations.

Examples of the pyrrolinium cation include a pyrrolinium cation, a pyrrolinium cation in which hydrogen bonded to nitrogen of the pyrrolinium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, and a hydroxyl group in the alkyl chain. Examples include a pyrrolium cation containing a functional group such as an ether group, a carbonyl group, a carboxyl group, an alkenyl group, an amino group, a nitrile group, a halogen group, and an aryl group, such as 1-methylpyrrolium cation, 1-ethylpyrrolium. A cation, a 1-propyl pyrrolinium cation, a 1-butyl pyrrolinium cation, etc. can be mentioned.

  Examples of the pyrazinium cation include a pyrazinium cation, a pyrazinium cation in which hydrogen bonded to nitrogen of the pyrazinium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, and an alkyl chain thereof. Examples thereof include a pyrazinium cation containing a functional group such as a hydroxyl group, an ether group, a carbonyl group, a carboxyl group, an alkenyl group, an amino group, a nitrile group, a halogen group, and an aryl group, such as a 1-methylpyrazinium cation. 1-ethylpyrazinium cation, 1-propylpyrazinium cation, 1-butylpyrazinium cation and the like.

Examples of the triazolium cation include a triazolium cation, a triazolium cation in which hydrogen bonded to a triazolium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, and an alkyl chain thereof. Examples include triazolium cations containing functional groups such as a hydroxyl group, an ether group, a carbonyl group, a carboxyl group, an alkenyl group, an amino group, a nitrile group, a halogen group, and an aryl group, such as 1,4-dimethyl-1,2 , 4-triazolium cation, 1,4-diethyl-1,2,4-triazolium cation and the like.

Examples of the isoquinolinium cation include an isoquinolinium cation, an isoquinolinium cation in which hydrogen bonded to nitrogen of the isoquinolinium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, Further, isoquinolinium cations containing functional groups such as hydroxyl group, ether group, carbonyl group, carboxyl group, alkenyl group, amino group, nitrile group, halogen group, aryl group in the alkyl chain can be mentioned. -Methylisoquinolinium cation, N-ethylisoquinolinium cation, N-propylisoquinolinium cation, N-butylisoquinolinium cation, N-hexylisoquinolinium cation, N-octylisoquinori Examples thereof include a nium cation.

Examples of the oxazolinium cation include an oxazolinium cation, an oxazolinium cation in which hydrogen bonded to nitrogen of the oxazolinium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, and an alkyl chain thereof. Examples thereof include oxazolinium containing a functional group such as a hydroxyl group, an ether group, a carbonyl group, a carboxyl group, an alkenyl group, an amino group, and a nitrile group. For example, 3-methyl-4-methyloxazolium cation, 3-ethyl- Examples include 4-methyloxazolium cation, 3-propyl-4-methyloxazolium cation, and 3-butyl-4-methyloxazolium cation.

  Examples of the thiazolinium cation include a thiazolinium cation, a thiazolium cation in which hydrogen bonded to nitrogen of a thiazolinium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, and an alkyl chain thereof. Examples include thiazolium cations containing a functional group such as a hydroxyl group, an ether group, a carbonyl group, a carboxyl group, an alkenyl group, an amino group, a nitrile group, a halogen group, and an aryl group, such as a 3-methylthiazolium cation. , 3-ethylthiazolium cation, 3-propylthiazolium cation, 3-butyl-4-methylthiazolium cation, and the like.

  Examples of the morpholinium cation include a morpholinium cation, a morpholinium cation in which hydrogen bonded to nitrogen of the morpholinium cation is substituted with a linear or branched alkyl group having 1 to 18 carbon atoms, and an alkyl chain thereof. Examples thereof include morpholinium cations containing a functional group such as a hydroxyl group, an ether group, a carbonyl group, a carboxyl group, an alkenyl group, an amino group, a nitrile group, a halogen group, and an aryl group, such as N-ethyl-N-methyl. Examples thereof include morpholinium cation, N-butyl-N-methylmorpholinium cation, N- (2-hydroxyethyl) -N-methylmorpholinium cation and the like.

Examples of the guanidinium cation include a guanidinium cation, a guanidinium cation substituted with nitrogen of a guanidinium cation and a linear or branched alkyl group having 1 to 18 carbon atoms, and an alkyl chain thereof. Examples thereof include a guanidinium cation containing a functional group such as a hydroxyl group, an ether group, a carbonyl group, a carboxyl group, an alkenyl group, an amino group, a nitrile group, a halogen group, and an aryl group. 1,3,3-tetramethylguanidinium cation, N, N, N ′, N ′, N ″, N ″ -hexaalkylguanidinium cation, N, N, N ′, N ′, N ″ -penta And alkyl-N ″ -benzylguanidinium cation.

  Examples of the anion constituting the ionic liquid include a halogen anion, a sulfur anion, a phosphorus anion, a cyan anion, a boron anion, a fluorine anion, a nitrogen oxide anion, and a carboxylate anion. .

Examples of the halogen-based anion include chloride ion, bromide ion, and iodo ion.

Examples of the sulfur anion include a sulfate anion, a hydrogen sulfate anion, and an alkyl sulfonate anion (for example, methane sulfonate, ethyl sulfonate, butyl sulfonate, benzene sulfonate, p-toluene sulfonate, 2, 4, 6 -Trimethylbenzene sulfonate, styrene sulfonate, 3-sulfopropyl methacrylate anion, 3-sulfopropyl acrylate, etc.), alkyl sulfate anion (for example, methyl sulfate anion, ethyl sulfate anion, butyl sulfate anion, octyl sulfate) Anion, 2- (2-methoxyethoxy) ethyl sulfate anion, etc.).

Examples of the phosphorus anion include a phosphate anion, a hydrogen phosphate anion, a dihydrogen phosphate anion, a phosphonate anion, a hydrogen phosphonate anion, a phosphinate anion, and an alkyl phosphate anion (eg, dimethyl phosphate, diethyl phosphate). , Dipropyl phosphate anion, dibutyl phosphate anion, etc.), alkyl phosphonate anion (eg, methyl phosphonate anion, ethyl phosphonate anion, propyl phosphonate anion, butyl phosphonate anion, methyl methyl phosphonate anion, etc.), alkyl Examples thereof include phosphinate anions and hexaalkylphosphate anions.

Examples of the cyan anion include tetracyanoborate anion, dicyanamide, thiocyanate anion, and isothiocyanate anion.

Examples of the boron anion include tetrafluoroborate anions, bisoxalate borate anions, tetraalkylborate anions such as tetraphenylborate, and the like.

Examples of the fluorine-based anion include bis (fluorosulfonyl) imide anion, bis (perfluoroalkylsulfonyl) imide anion (for example, bis (trifluoromethylsulfonyl) imide anion, bis (pentafluoroethylsulfonyl) imide, bis (heptafluoro). Propanesulfonyl) imide anion, bis (nonafluorobutylsulfonyl) imide, etc.), perfluoroalkylsulfonate anion (eg, trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, heptafluoropropanesulfonate anion, nonaflate anion, Perfluorooctanesulfonate anion, etc.), fluorophosphate anion (eg hexafluorophosphate anion, tri (pentafluoroethyl) ) Trifluorophosphate anion, etc.), tris (perfluoroalkylsulfonyl) methide anion (for example, tris (trifluoromethanesulfonyl) methide anion, tris (pentafluoroethanesulfonyl) methide anion, tris (heptafluoropropanesulfonyl) methide anion, tris (nonafluoro) Butanesulfonyl) methide anion and the like), fluorohydrogen anion and the like.

Examples of the nitrogen oxide anion include nitrate anion and nitrite anion.

The carboxylate anion is an organic acid anion having at least one carboxylate anion (—COO ⁻ ) in the molecule, and includes a functional group having a hetero atom such as an oxygen atom, a nitrogen atom, or a sulfur atom. May be. Although not particularly limited, examples of the carboxylate anion include a saturated aliphatic carboxylate anion, an unsaturated aliphatic carboxylate anion, an alicyclic carboxylate anion, an aromatic carboxylate anion, a saturated aliphatic hydroxycarboxylate anion, Saturated aliphatic hydroxycarboxylic acid anion, alicyclic hydroxycarboxylic acid anion, aromatic hydroxycarboxylic acid anion, carbonylcarboxylic acid anion, alkyl ether carboxylic acid anion, halogen carboxylic acid anion, amino acid anion and the like.

The saturated aliphatic carboxylate anion is composed of a linear or branched aliphatic saturated hydrocarbon group and one or more carboxylate anions, and preferably has 1 to 22 carbon atoms. Specifically, for example, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, pentadecylic acid, palmitic acid, margaric acid, stearin Acid, behenic acid, isobutyric acid, 2-methylbutyric acid, isovaleric acid, 2-ethylhexanoic acid, isononanoic acid, isopalmitic acid, isostearic acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid , Anions in which protons are dissociated from suberic acid, azelaic acid, sebacic acid and the like.

The unsaturated aliphatic carboxylate anion is composed of a linear or branched aliphatic unsaturated hydrocarbon group and one or more carboxylate anions, and preferably has 3 to 22 carbon atoms. Specifically, for example, protons dissociated from acrylic acid, methacrylic acid, crotonic acid, palmitoleic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, eleostearic acid, arachidonic acid, maleic acid, fumaric acid, etc. Anions.

The alicyclic carboxylate anion is composed of a saturated or unsaturated carbocycle having no aromaticity and one or more carboxylate anions, and preferably has 6 to 20 carbon atoms. Among these, alicyclic carboxylate anions having a cyclohexane ring skeleton are preferable, and specific examples include anions in which protons are dissociated from cyclohexanecarboxylic acid and cyclohexanedicarboxylic acid.

The aromatic carboxylate anion consists of a single ring or a plurality of rings having aromaticity and one or more carboxylate anions, and preferably has 6 to 20 carbon atoms. Among them, an aromatic carboxylate anion having a benzene ring skeleton is preferable, and specific examples include anions in which protons are dissociated from benzoic acid, cinnamic acid, phthalic acid, isophthalic acid, terephthalic acid and the like.

The saturated aliphatic hydroxycarboxylate anion is composed of a linear or branched aliphatic saturated hydrocarbon group, one or more carboxylate anions and one or more hydroxyl groups, and preferably has 2 to 24 carbon atoms. Among these, a saturated aliphatic hydroxycarboxylate anion having 2 to 7 carbon atoms and having 1 to 4 hydroxyl groups is preferable. Specifically, for example, glycolic acid, lactic acid, tartronic acid, glyceric acid, hydroxyacetic acid, hydroxybutyric acid, 2-hydroxydecanoic acid, 3-hydroxydecanoic acid, 12-hydroxystearic acid, dihydroxystearic acid, cerebronic acid, Examples include anions in which protons are dissociated from malic acid, tartaric acid, citramalic acid, citric acid, isocitric acid, leucine acid, mevalonic acid, pantoic acid and the like.

The unsaturated aliphatic hydroxycarboxylate anion is composed of a linear or branched aliphatic unsaturated hydrocarbon group, one or more carboxylate anions, and one or more hydroxyl groups, and preferably has 3 to 22 carbon atoms. Specific examples include anions in which protons are dissociated from ricinoleic acid, ricinoleic acid, ricinaleic acid, and the like.

The alicyclic hydroxycarboxylic acid anion is composed of a saturated or unsaturated carbocyclic ring having no aromaticity, one or more carboxylic acid anions, and one or more hydroxyl groups, and preferably has 6 to 20 carbon atoms. Among them, alicyclic hydroxycarboxylic acid anions having a 6-membered skeleton having 1 to 4 hydroxyl groups are preferable. Specifically, for example, hydroxycyclohexanecarboxylic acid, dihydroxycyclohexanecarboxylic acid, quinic acid (1,3,4) , 5-tetrahydroxycyclohexanecarboxylic acid), shikimic acid, and the like, and anions in which protons are dissociated.

The aromatic hydroxycarboxylate anion is composed of a single ring or a plurality of rings having aromaticity, one or more carboxylate anions, and one or more hydroxyl groups, and preferably has 6 to 20 carbon atoms. Among them, an aromatic carboxylate anion having a benzene ring skeleton having 1 to 3 hydroxyl groups is preferable. Specific examples include salicylic acid, hydroxybenzoic acid, dihydroxybenzoic acid, trihydroxybenzoic acid, hydroxymethylbenzoic acid, and vanillin. Examples include anions in which protons are dissociated from acid, syringic acid, pyrotocatechuic acid, gentisic acid, orceric acid, mandelic acid, benzylic acid, atrolactic acid, furoletic acid, coumaric acid, umbelic acid, caffeic acid, ferulic acid, sinapinic acid, etc. It is done.

The carbonyl carboxylate anion is a carboxylic acid anion having 3 to 22 carbon atoms having a carbonyl group in the molecule, and preferably a carbonyl carboxylate anion having 1 to 2 carbonyl groups and having 3 to 7 carbon atoms. Among them, a carbonyl carboxylate anion represented by CH ₃ ((CH ₂ ) _n CO (CH ₂ ) _p ) COO ⁻ (n and p are integers of 0 to 2) is preferable. Specific examples include anions in which protons are dissociated from pyruvic acid or the like.

The alkyl ether carboxylate anion is a C 22-22 carboxylate anion having an ether group in the molecule, including a polyoxyethylene alkyl ether carboxylate anion, and a carbon number of 2 having 1-2 ether groups. ~ 12 alkylcarboxylate anions are preferred. Among _{them, CH 3 (CH 2) q} O (CH 2) r COO - (q and r is an integer of 0 to 4.) Is preferably an alkyl ether carboxylate anion represented by. Specific examples include anions in which protons are dissociated from methoxyacetic acid, ethoxyacetic acid, methoxybutyric acid, ethoxybutyric acid, and the like.

As the halogen carboxylate anion, a halogen carboxylate anion having 2 to 22 carbon atoms is preferable. Specific examples include anions in which protons are dissociated from fluorine-substituted halogen carboxylic acids such as trifluoroacetic acid, pentafluoropropionic acid, and perfluorononanoic acid.

  The amino acid is not particularly limited, but glycine, alanine, glutamic acid, arginine, asparagine, aspartic acid, isoleucine, glutamine, glutamic acid, glycine, histidine, cysteine, leucine, lysine, proline, phenylalanine, threonine, serine, tryptophan, tyrosine , Methionine, valine, sarcosine, aminobutyric acid, methylleucine, aminocaprylic acid, aminohexanoic acid, norvaline, aminovaleric acid, aminoisobutyric acid, thyroxine, creatine, ornithine, opine, theanine, tricolomine, kainic acid, domoic acid, ibotenic acid , Anions in which protons are dissociated from acromelic acid, cystine, hydroxyproline, phosphoserine, desmosine and the like.

The ionic liquid used in the ink composition for a writing instrument of the present invention is not particularly limited to a cation and an anion, but the cation contains an atom capable of coordinating to a metal such as nitrogen, phosphorus, sulfur, etc. Since the anticorrosion film is formed, the anticorrosion for the metal member at the tip end of the chip is excellent. In particular, an ionic liquid having a coordinating functional group containing nitrogen, oxygen, phosphorus, or sulfur atoms in one or both of the cation and anion is particularly suitable because it forms a good anticorrosive film and exhibits an anticorrosive effect. It is.
The ionic liquid containing a nitrogen atom cation is relatively safer than the raw material for producing a cation, sulfonium cation, and the operability, price, and diversity. The structure of the ionic liquid can be designed widely with respect to the required physical properties, and it is preferable because the physical properties can be easily finely adjusted. Examples of the cation containing a nitrogen atom include an ammonium cation, an imidazolium cation, a pyridinium cation, a pyrrolidinium cation, a piperidinium cation, a pyrrolium cation, a pyrazinium cation, a triazolium cation, an isoquinolinium cation, and an oxazolyl. Examples include nium cation, morpholinium cation, pyrimidinium cation, piperazinium cation, triazinium cation, quinolinium cation, indolinium cation, quinoxalinium cation, isoxazolium cation, and cationic amino acid. It is done. In particular, an ammonium cation, an imidazolium cation, a pyridinium cation, a pyrrolidinium cation, and a piperidinium cation are preferable.
When the ionic liquid used in the ink composition is hydrophilic, the biodegradability is high and the environmental load is low. Furthermore, hydrophilic ionic liquids having a hydrophilic functional group such as a hydroxyl group, a carbonyl group, a carboxyl group or an ether group on the cation or anion of the ionic liquid are highly biodegradable, have a low environmental load, and are soluble in water. Is higher and preferred.
In addition, when the ionic liquid is a combination of a cation and an anion derived from a biological substance, it is not only highly biodegradable but also safer than a solvent such as benzyl alcohol.

  The ionic liquid may be used alone or in combination of two or more, and is not particularly limited, but is preferably 50% by weight or more, particularly preferably 60% by weight as the main solvent in the ink composition. It applies with the above composition ratio. At that time, water may be added as an auxiliary solvent, or an organic solvent such as alcohol, glycerin, glycol ether, phenyl glycol, or benzyl alcohol may be added as necessary. In particular, when applied to a writing instrument in the form of a ball-point pen, if the composition ratio of the ionic liquid is 50% or more, the writing resistance value becomes low during writing, lightness and smoothness of writing can be obtained, and there is a possibility that handwriting may be blurred. Can be reduced.

The colorant is not particularly limited, and dyes and pigments applicable to general-purpose water-based inks and oil-based inks that can be dissolved or dispersed in each medium can be used. Specific examples thereof are shown below. To do.
As the dye in the aqueous colorant, an acid dye, a basic dye, a direct dye, or the like can be used.
Examples of the acid dye include New Coxin (CI. 16255), Tartrazine (CI. 19140), Acid Blue Black 10B (CI. 20470), Guinea Green (CI. 42085), Brilliant Blue FCF. (CI.42090), Soluble Blue (C.I.42755), Naphthalene Green (C.I.44025), Eosin (C.I.45380), Phloxin (C.I.45410), Erythrosine (C I.45430), nigrosine (C.I. 50420), acid flavin (C.I. 56205) and the like are used.
Examples of basic dyes include chrysoidine (C.I. 11270), crystal violet (C.I. 42555), malachite green (C.I. 42000), Victoria Blue FB (C.I. 44045), rhodamine B (C I. 45170), acridine orange NS (C.I. 46005), methylene blue B (C.I. 52015) and the like are used.
As direct dyes, Congo Red (C.I. 22120), Direct Sky Blue 5B (C.I. 24400), Violet BB (C.I. 27905), Direct Deep Black EX (C.I. 30235), Kaya Las Black G Conch (C.I. 35225), Direct Fast Black G (C.I. 35255), Phthalocyanine Blue (C.I. 74180) and the like are used.

Examples of the pigment include inorganic pigments such as carbon black and ultramarine blue, and organic pigments such as copper phthalocyanine blue, as well as water-dispersed pigment products that are finely and stably dispersed in an aqueous medium in advance using a surfactant or resin. For example, C.I. I. Pigment Blue 15: 3B [Product name: Sandy Super Blue GLL, pigment content 24%, manufactured by Sanyo Dye Co., Ltd.], C.I. I. Pigment Red 146 [Product name: Sandy Super Pink FBL, pigment content 21.5%, manufactured by Sanyo Dye Co., Ltd.], C.I. I. Pigment Yellow 81 [Product name: TC Yellow FG, pigment content about 30%, manufactured by Dainichi Seika Kogyo Co., Ltd.], C.I. I. Pigment Red 220/166 [Product name: TC Red FG, pigment content of about 35%, manufactured by Dainichi Seika Kogyo Co., Ltd.].
As the resin for dispersing the pigment, polyamide resin, polyurethane resin, polyester resin, epoxy resin, melamine resin, phenol resin, silicone resin, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, Examples thereof include polystyrene, acrylic acid resin, maleic acid resin, cellulose, dextran, casein, and derivatives thereof, and copolymers of the above-described resins.
As the fluorescent pigment, a fluorescent pigment in the form of fine particles of a synthetic resin in which various fluorescent dyes are formed into a solid solution in a resin matrix can be used.
Also, white pigments such as titanium oxide, metal powders such as aluminum, pearl pigments in which the surface of a core material selected from natural mica, synthetic mica, alumina, and glass pieces is coated with a metal oxide such as titanium dioxide, cholesteric liquid crystal type glitter It is also possible to use a functional pigment.
Furthermore, a thermochromic pigment such as a microcapsule pigment encapsulating a thermochromic composition (a heat decoloring type pigment) or a microcapsule pigment encapsulating a dye or a pigment can be used together with the thermochromic composition. .

The thermochromic composition includes (a) an electron-donating color-forming organic compound, (b) an electron-accepting compound, and (c) a reversible thermochromic composition comprising a reaction medium that determines the temperature at which the color reaction occurs. The composition is suitable and is encapsulated in microcapsules and applied as a reversible thermochromic microcapsule pigment.
Examples of the reversible thermochromic composition include those described in Japanese Patent Publication No. 51-44706, Japanese Patent Publication No. 51-44707, Japanese Patent Publication No. 1-29398, etc., at a predetermined temperature (discoloration point). Discolored before and after, decolored state in the temperature range above the high temperature side discoloration point, color development state in the temperature range below the low temperature side discoloration point, only one specific state exists in the normal temperature range among the two states, The other state is maintained as long as the heat or cold required to develop the state is applied, but when the heat or cold is no longer applied, the hysteresis width returns to the state exhibited in the normal temperature range. A heat decolorable microcapsule pigment in which a reversible thermochromic composition having relatively small characteristics (ΔH = 1 to 7 ° C.) is encapsulated in a microcapsule can be applied.
Furthermore, comparatively large hysteresis characteristics (ΔH = 8 to 50) described in JP-B-4-17154, JP-A-7-179777, JP-A-7-33997, JP-A-8-39936, and the like. ° C), and exhibit large hysteresis characteristics described in JP-A-2006-137886, JP-A-2006-188660, JP-A-2008-45062, JP-A-2008-280523, In other words, the shape of the curve plotting the change in color density due to temperature change differs greatly between when the temperature is raised from the lower temperature side than the color change temperature range and when the temperature is lowered from the higher temperature side than the color change temperature range. The color changes following the path, and the color development state in the low temperature range below the complete color development temperature, or the color erase state in the high temperature range above the complete color erase temperature is in the specific temperature range. Microcapsule pigment was contained a reversible thermochromic composition heated decolorizable having chroma memory property can be applied.
Specifically, as the reversible thermochromic composition having color memory, a complete color development temperature can be obtained only in a freezing room, a cold district, etc., that is, −50 to 0 ° C., preferably −40 to − 5 ° C., more preferably −30 to −10 ° C., and complete decoloring temperature obtained from a frictional heat generated by a friction body, a heating body such as a hair dryer, that is, 50 to 95 ° C., preferably 50 to 90 ° C. More preferably, by specifying the range of 60 to 80 ° C. and specifying the ΔH value of 40 to 100 ° C., it is possible to effectively function to maintain the color exhibited in the normal state (daily life temperature range).

  As the dye in the oil-based colorant, a conventionally known oil-soluble dye can be used. Specifically, Rhodamine B base (CI 45170B, Taoka Dye Manufacturing Co., Ltd.), Soldan Red 3R (CI) 21260, Chugai Kasei Co., Ltd.), Victoria Blue F4R (C.I. 42563B), Nigrosine Base LK (C.I. 50415) (above, BASF, Germany), Bali Fast Yellow # 3104 (C.I. I.13900A), varifast yellow # 3105 (C.I. 18690A), Orient Spirit Black AB (C.I. 50415), varifast black # 3804 (C.I. 12195), varifast yellow # 1109, Fast Orange # 2210, Bali Fast Red # 1320, Bali Fast Blue # 1 05, Bali Fast Violet # 1701 (manufactured by Orient Chemical Co., Ltd.), Spiron Black GMH Special, Spiron Yellow C-2GH, Spiron Yellow C-GNH, Spiron Red C-GH, Spiron Red C-BH, Spiro blue C-RH, Spiro violet C-RH, S. P. T. T. Orange 6, S. P. T. T. Examples include Blue 111 (manufactured by Hodogaya Chemical Co., Ltd.). Furthermore, C.I. I. Basic Blue 1, 7, 7, 8, C.I. I. Basic violet 1, 3 and C.I. I. Basic dyes such as Basic Red 1 and C.I. I. Examples thereof include salt-forming dyes with acid dyes selected from Acid Yellow 23, 36 and the like.

Specific examples of the pigment include C.I. I. PIGMENT RED2, 3, 5, 8, 17, 17, 22, 31, 38, 41, C.I. I. PIGMENT ORANGE 5, 10, 13, 16, 36, 40, 43, 61, 64, 71, 73, C.I. I. PIGMENT VIOLET 19, 23, 31, 33, 36, 37, 38, 50, C.I. I. PIGMENT BLUE 2, 9, 15, 15: 1, 15: 2, 15: 3, 15: 4, 16, 17, 17, 22, 25, 28, 29, 36 60, 68, 76, C.I. I. PIGMENT BROWN 23, 25, 26, C.I. I. PIGMENT YELLOW 1, 3, 12, 13, 24, 83, 93, 94, 95, 97, 99, 128, 139, 153, 173, C.I. I. Organic pigments such as PIGMENT GREEN 7, 10 and 36, carbon black such as black iron oxide, furnace black, channel black, thermal black, acetylene black, yellow iron oxide, red iron oxide, ultramarine blue, bitumen, cobalt blue, Examples include inorganic pigments such as titanium yellow, turquoise, molybdate orange, and titanium oxide.
Furthermore, as other pigments, fluorescent pigments, pearl pigments, phosphorescent pigments, metal pigments, composite metal pigments, metal oxide pigments, thermochromic pigments, and the like can be used.

  The colorant can be used singly or in combination of two or more, and is not particularly limited, but is used in the range of 1 to 35% by weight, preferably 2 to 20% by weight in the ink composition. It is done.

Furthermore, a resin can be added to impart adhesion to the paper surface or viscosity.
Among the resins, examples of water-soluble resins include alkyd resins, acrylic resins, styrene maleic acid copolymers, cellulose derivatives, polyvinyl pyrrolidone, polyvinyl alcohol, and dextrin.
Examples of oil-soluble resins include ketone resins, sulfoamide resins, acrylic resins, maleic acid resins, copolymers of styrene and maleic esters, copolymers of styrene and acrylic acid or esters thereof, ester gums, xylene resins, urea Examples thereof include resins, polyamide resins, alkyd resins, phenol resins, alkylphenol resins, terpene phenol resins, rosin resins and hydrogenated compounds thereof, polyvinyl butyral, polyvinyl acetal, polyvinyl alkyl ether, polyvinyl pyrrolidone, and polyethylene oxide.
The resin can be used alone or in combination of two or more, and is used in the range of 0.1 to 30% by weight in the total amount of the ink composition.

In addition, various additives can be added as necessary.
Specifically, as conventionally applied to water-based inks, for example, inorganic salts such as sodium carbonate, sodium phosphate and sodium acetate, pH adjusters such as organic basic compounds such as water-soluble amine compounds, benzotriazole, Anticorrosives (rust preventive) such as tolyltriazole, saponin, carboxylic acid, 1,2-benzthiazolin-3-one salt, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2, 3, 5 , 6-Tetrachloro-4- (methylsulfonyl) pyridine and other preservatives or antifungal agents, urea, sorbit, mannitol, sucrose, glucose, reduced starch hydrolysates, wetting agents such as sodium pyrophosphate, antifoaming Fluorine surfactants and nonionic surfactants that improve the penetrability of the agent and ink may be used. Further, a lubricant can be added, such as metal soap, polyalkylene glycol fatty acid ester, ethylene oxide addition type cationic surfactant, phosphate ester type surfactant, N-acyl amino acid type surfactant, dicarboxylic acid type surfactant. , Β-alanine type surfactant, 2,5-dimercapto-1,3,4-thiadiazole and its salts and oligomers, 3-amino-5-mercapto-1,2,4-triazole, thiocarbamate, dimethyl A dithiocarbamate, α-lipoic acid, a condensate of N-acyl-L-glutamic acid and L-lysine, a salt thereof, or the like is used. Further, oligomers of N-vinyl-2-pyrrolidone, oligomers of N-vinyl-2-piperidone, N-vinyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, ε-caprolactam, N-vinyl-ε-caprolactam It is also possible to add a thickening inhibitor such as an oligomer.
In addition, a shear thinning agent can be added. For example, xanthan gum, welan gum, zeta sea gum, dieutan gum, macrohomopsis gum, succinoglycan whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose ( Average molecular weight of about 1 to 8 million), guar gum, locust bean gum and derivatives thereof, hydroxyethyl cellulose, alginic acid alkyl esters, polymers having a molecular weight of 100,000 to 150,000 based on alkyl esters of methacrylic acid, glucomannan, agar And carbohydrates having gelling ability extracted from seaweed such as carrageenin, poly N-vinyl-carboxylic acid amide cross-linked product, benzylidene sorbitol and benzylidene xylitol or their derivatives, cross-linkable acrylic acid polymer, inorganic fine particles, H Nonionic surfactants B values 8 to 12, the metal salts and amine salts of dialkyl sulfosuccinic acid and the like.

  Furthermore, viscosity modifiers such as bentonite, synthetic fine silica, hydrogenated castor oil, fatty acid amide wax, antiseptics, anticorrosives (rust inhibitors), antifoaming agents, lubricants, which are applied to oil-based inks. Various additives such as a dispersant, an anti-scratch agent, an anti-leakage agent, and a surfactant can also be added.

When the ink composition is applied to a ballpoint pen, the ink viscosity is preferably adjusted to a range of 100 to 100,000 mPa · s.
In the said range, especially favorable writing performance will be expressed at the time of writing on paper. When the viscosity is lower than the above range, there is a possibility that handwriting blurring or back-through, drooping at the time of storage, and the like are likely to occur, and when the viscosity is high, followability at the time of writing may be deteriorated.

  The ink composition for a writing instrument of the present invention is filled in the exterior of a writing instrument such as a fountain pen, such as a marking pen or ballpoint pen with a fiber tip, felt tip, plastic tip, metal tip, or ballpoint tip attached to the tip of the writing. The writing instrument is a cap-type with a cap that covers the pen tip, and has a knock-out type such as a knock type, a rotary type, a slide type, etc. Also good.

When filling the marking pen, the structure and shape of the marking pen itself are not particularly limited. For example, a pen tip for a marking pen such as a fiber chip, a felt chip, a plastic chip (a shell type, a chisel type, a brush pen type) Etc.) is attached to the writing tip, and an ink occlusion body consisting of a fiber bundle housed in the shaft tube is impregnated with ink, and ink is supplied to the writing tip, ink is stored directly in the shaft tube, and comb A structure that supplies a predetermined amount of ink to the writing tip by interposing a groove-like ink flow adjusting member or an ink flow adjusting member made of a fiber bundle, directly storing the ink inside the shaft tube, and writing the tip by a valve mechanism And a marking pen having a structure for supplying a predetermined amount of ink.
Further, in addition to a single nib, a double-headed form in which nibs having different thicknesses and shapes are provided at both ends of the shaft cylinder may be used. In the double-headed form, one end may be a ballpoint pen.

When filling the ball-point pen, the structure and shape of the ball-point pen itself are not particularly limited. For example, an ink occlusion body composed of a fiber bundle housed in the shaft tube is impregnated with ink and supplied to the writing tip. Structure, ink is stored directly inside the shaft cylinder, and there is an ink storage tube filled with the ink composition in the shaft cylinder, with a comb groove-shaped ink flow control member and an ink flow control member consisting of fiber bundles interposed The ink containing tube communicates with a tip having a ball attached to the tip, and a ballpoint pen having a structure in which a liquid stopper for backflow prevention is in close contact with the end surface of the ink. In addition, general-purpose balls such as resin and metal can be applied as the balls.
The ink composition of the present invention is particularly useful when applied to a writing instrument in the form of a ballpoint pen. This is because the ionic liquid acts on the ball and the ball seat, and the contact resistance is reduced during writing, so that a smooth writing feeling can be obtained. In particular, when a metal ball such as cemented carbide is used, it is particularly useful because it does not cause the above-described precipitation or the like as a problem of the prior art, and does not blur and provides a light and smooth writing feeling.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. In addition, the numerical value of a composition in a table | surface shows a weight part.

  The water content of the ionic liquid used as the composition of the writing instrument inks in Tables 1 and 2 was measured by the Karl Fischer method or a differential thermothermal gravimetric simultaneous measurement device (TG / DTA). Then, anhydrous ionic liquids (ionic liquids 7, 8, 13, 14, 18) and hydrous ionic liquids (ionic liquids 1-6, 9-12, 15-17, 19-23) were added to the screw tube and sealed. , And water-containing ionic liquid was added to the screw tube and dried under reduced pressure to make an anhydrous ionic liquid, and then the sealed sample was allowed to stand for 24 hours in an incubator set at −5, 0, and 25 ° C. Solid) was confirmed. The results are shown in Tables 1 and 2. In addition, the ionic liquid used for the following evaluation tests used the thing of the moisture content shown in Table 1, 2 as it was.

Corrosion test In ion-exchanged water, each ionic liquid 1, 2, 3, 5, 6, 8, 12, 13, 14, 17, 18, 21, 22 in Tables 1 and 2, and ionic liquids 2, 3, A cemented carbide ball having a diameter of 0.5 mm was immersed in a sample diluted to 90 wt% by adding ion exchange water to 5, 6, 8, 12, 17, and 22. After standing in an incubator at 80 ° C. for 8 days, the corrosion of the balls was removed from the solution each time and visually confirmed. As a result, only the balls immersed in water were discolored and corroded, whereas the balls in other samples were not corroded after standing for 8 days, and the ionic liquid corroded against the cemented carbide balls. It was shown that it has anticorrosive effect even in the environment where water is present.

Metal ion (metal salt) solubility test The solubility of the ionic liquid with respect to each ion such as nickel ion, cobalt ion, chromium ion, etc., which is expected to be eluted from the cemented carbide ball, was confirmed. In each ionic liquid 1, 2, 3, 5, 6, 8, 12, 13, 14, 17, 18, 21, 22 in Tables 1 and 2, nickel ions are 0.1% by weight with respect to the ionic liquid. As such, nickel (II) chloride hexahydrate was added and stirred with ultrasound. Furthermore, the same operation was performed using cobalt chloride hexahydrate and chromium (III) chloride hexahydrate, respectively. As a result, it was shown that any metal compound was dissolved and the ionic liquid was soluble in the metal ion (metal salt).

Preparation of Ballpoint Pen Inks The raw materials were mixed in the blending amounts of Examples and Comparative Examples shown in Tables 3 to 5, stirred at 400 rpm for 1 hour at 25 ° C. with a disper, and then filtered to obtain a ballpoint ink composition. . In addition, the viscosity of each obtained ink composition of Examples 1-26 was the range of 100-100,000 mPa * s.

The contents of the raw materials other than the ionic liquid in Tables 3 to 5 will be described along the note numbers.
(1) Product name: Water Black R510, manufactured by Orient Chemical Co., Ltd.
(2) Product name: Bali Fast Red 1308, manufactured by Orient Chemical Co., Ltd.
(3) Product name: Bali Fast Black 3830, manufactured by Orient Chemical Co., Ltd.
(4) Product name: Bali Fast Blue 1605, manufactured by Orient Chemical Co., Ltd.
(5) Product name: Oil Pink 312, manufactured by Orient Chemical Co., Ltd.
(6) Carbon black, manufactured by Mitsubishi Chemical Corporation, trade name: MA-100
(7) 4.5 parts of 2- (2-chloroanilino) -6-di-n-butylaminofluorane as component (a) and 1,1-bis (4'-hydroxyphenyl) n- as component (b) Reversible thermochromic composition comprising 4.5 parts of decane, 7.5 parts of 2,2-bis (4'-hydroxyphenyl) hexafluoropropane, and 50.0 parts of 4-benzyloxyphenylethyl caprate as the component (c) Microcapsule pigment encapsulating a product (T ₁ : −20 ° C., T ₂ : −9 ° C., T ₃ : 40 ° C., T ₄ : 57 ° C., ΔH: 63 ° C., average particle size: 2.5 μm, black to colorless Change color)
(8) Polyvinylpyrrolidone resin, manufactured by BASF Corp., trade name: Rubytec K-30
(9) Phosphate ester surfactant, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Prisurf AL

Preparation of Ink Backflow Preventing Body After adding 1.5 parts of fatty acid amide as a thickener to 98.5 parts of polybutene as a base oil, an ink backflow preventing body was obtained by kneading with 3 rolls.

Preparation of ballpoint pen Each of the ink compositions is filled in a ballpoint refill in which a stainless steel tip holding a ball of cemented carbide having a diameter of 0.5 mm is fitted to one end of a transparent polypropylene pipe. After arranging the ink backflow preventive body, the ballpoint pen refill was assembled into a shaft cylinder, and a cap was attached to produce a ballpoint pen.

The following tests were performed using the obtained ballpoint pens.
Mechanical writing test (writing resistance measurement)
The writing resistance value was measured when the ballpoint pen, which was confirmed to be writable, was written at room temperature using a disc type drawing machine (writing angle 75 °, load 100 g, writing speed 4 m / min). In addition, the obtained value is an average value (unit: g) of three writing resistance value data.
Handwritten writing test The above-mentioned ball-point pen, which has been confirmed to be writable, is handwritten on a report paper (JIS P3201 writing paper A) at room temperature. confirmed.
The results of each test are shown below.

In addition, the evaluation regarding the symbol in the said Table 6 is as follows.
Handwritten writing test Writing feeling ○: Light and smooth writing feeling.
X: Light but not smooth or smooth but heavy writing feeling.

  In Examples 1 to 26, the ionic liquid prevented elution of metal ions from the metal member due to its anticorrosive effect, and dissolved the eluted metal ions to suppress the generation of precipitates derived from metal ions. In addition, the non-volatile characteristics of ionic liquids that are not found in water and organic solvents make it possible to keep the tip of the tip moist, so writing is good, writing resistance is low, and ink ejection is good. Thus, good handwriting was formed with a light and smooth writing feeling.

Claims (4)

An ink composition for ballpoint pens , wherein an ionic liquid which is liquid at 25 ° C. is applied as a main solvent of 50% by weight or more in the ink composition and contains a colorant. The ink composition for a ballpoint pen according to claim 1, wherein the ionic liquid is liquid at 0 ° C. The anion constituting the ionic liquid is any one of a halogen anion, a sulfur anion, a phosphorus anion, a boron anion, a fluorine anion, a nitrogen oxide anion, and a carboxylate anion. Ink composition for ballpoint pens. A ballpoint pen comprising the ink composition for a ballpoint pen according to any one of claims 1 to 3 .