JP2012031230A - O/w type emulsion ink composition for ball-point pen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink composition for a ball-point pen free from offset of handwriting and superior in water resistance and writing feeling.SOLUTION: An O/W type emulsion ink composition for a ball-point pen is obtained by emulsifying and dispersing an oily ingredient comprising an oil-soluble dye as a colorant and an organic solvent which dissolves the dye, in water with a polyglycerol fatty acid ester having HLB of 8 or less, an 8C or more fatty acid dimethylaminopropyl amide and/or fatty acid diethylaminoethyl amide, and a 3-6C organic acid.

Description

  The present invention relates to an O / W emulsion ink composition for ballpoint pens that has excellent water resistance of handwriting, no show-through, excellent writing feeling, and good temperature stability.

  Conventionally, water-based ballpoint pen inks and water-based gel ballpoint pen inks that use water-soluble dyes have the characteristics that the handwriting is vivid and the writing feeling is good, but have the drawback that the water resistance of the handwriting is inferior. Aqueous pigment gel ballpoint pen inks in which a colorant is used as a pigment to improve water resistance have a high ink viscosity and poor writing quality in order to improve writing density and prevent sedimentation. Oil-based ballpoint pen ink in which an oil-soluble dye is dissolved in an organic solvent has good water resistance because the dye has water resistance, but if the viscosity is lowered to improve the writing quality, a show-through in which the organic solvent penetrates into paper occurs. For this reason, the viscosity is increased to prevent show-through, but the writing quality becomes heavy.

  Therefore, with an O / W emulsion ballpoint pen ink in which an oil phase component composed of an oil-soluble dye as a colorant and an organic solvent is emulsified and dispersed in water using an emulsifier, the writing quality of the aqueous phase and the water resistance of the oil-soluble dye are improved. It is thought that both can be achieved.

Conventionally, it is obtained from an oily phase comprising an oily solution in which at least a dye as a colorant is dissolved in an organic solvent and an aqueous phase containing at least water, using an emulsifier having an aromatic ring having an ethylene oxide addition mole number of 40 mol or more. Water-based ballpoint pen ink composition comprising an oil-in-water emulsion (Patent Document 1), a nonionic oil-soluble polymer, a hydrophobic high-boiling organic solvent having a boiling point of 150 ° C. or higher, and colored fine particles containing an oil-soluble dye are anionic A colored fine particle dispersion (Patent Document 2) obtained by dispersing in a water-based medium using a type surfactant or a nonionic surfactant is known.
However, when a nonionic surfactant having a relatively high HLB of about 8-18, which is usually used for preparing an O / W emulsion, is mixed into an emulsion ink, the surfactant is added to the handwriting on the paper together with the colorant. Therefore, when the handwriting gets wet with water, re-emulsification occurs, and there is a problem that the handwriting flows into the water even though the oil-soluble dye is used.

JP2009-292287A JP 2001-335734 A

The O / W type emulsion ink has sufficient water resistance.
However, emulsions using surfactants with high HLB are susceptible to environmental temperature due to the cloud point of surfactants in addition to re-emulsification of handwriting, and when placed in a certain high temperature environment, etc. There was a possibility that the emulsion was broken and aggregated or separated into an oil phase and an aqueous phase.

  The present invention provides a stable emulsion ink that has sufficient water resistance, sufficient heat resistance, good temperature stability and is not easily destroyed, and contains water but does not show back. Is intended to obtain a good O / W emulsion ink.

  The present invention relates to an oily component comprising an oil-soluble dye as a colorant and an organic solvent for dissolving the dye, a polyglycerol fatty acid ester having an HLB of 8 or less, a fatty acid dimethylaminopropylamide having 8 or more carbon atoms, and / or Alternatively, the gist is an O / W emulsion ink composition for ballpoint pens emulsified and dispersed in water with fatty acid diethylaminoethylamide and an organic acid having 3 to 6 carbon atoms.

A polyglycerin fatty acid ester having an HLB of 8 or less is a good surfactant for preparing a W / O type emulsion, but this alone is too weak in affinity with water to make an O / W type emulsion difficult.
However, when fatty acid dimethylaminopropylamide and / or fatty acid diethylaminoethylamide having 8 or more carbon atoms and an organic acid having 3 to 6 carbon atoms are used in combination, polyglycerin fatty acid ester having HLB8 or less firmly wraps the oil phase component, The fatty acid part of fatty acid dimethylaminopropylamide and / or fatty acid diethylaminoethylamide having 8 or more carbon atoms enters the polyglycerin fatty acid ester layer of HLB 8 or less, and the dimethylaminopropylamide and / or diethylaminoethylamide part is salted with lactic acid. As a result, it has a strong affinity for water, so that an O / W emulsion in which the oil phase component is finely dispersed in water can be formed.
As a result, water, lactic acid, and solvent have a strong affinity with paper when written on paper, so they penetrate first, and the oil phase component remains on the paper, but even if the handwriting on the paper gets wet with water, Since glycerin fatty acid ester prevents the handwriting from flowing out into water due to re-emulsification, it is considered that an ink excellent in water resistance can be obtained.

  The polyglycerin fatty acid ester used in the present invention has an HLB of 8 or less, and if an HLB of more than 8 is used, an O / W emulsion cannot be formed or the total amount of the oil phase becomes oil droplets. The oil phase cannot be separated from the ink and settled, and the water resistance of the handwriting is reduced. Moreover, a solid thing is preferable at normal temperature, and a liquid thing at normal temperature may have the low stability of an emulsion at high temperature. Examples of the polyglyceryl fatty acid ester used in the present invention include diglyceryl monostearate, diglyceryl monooleate, diglyceryl dioleate, diglyceryl monoisostearate, tetraglyceryl monostearate, tetraglyceryl monooleate, and tristearin. Tetraglyceryl acid, tetraglyceryl pentastearate, hexaglyceryl tristearate, hexaglyceryl pentastearate, decaglyceryl tristearate, decaglyceryl trioleate, decaglyceryl pentastearate, decaglyceryl pentaisostearate, decaglyceryl pentaoleate Glyceryl, heptabehenic acid decaglyceryl, dekaleic acid decaglyceryl, dodecabehenic acid decaglyceryl, etc. Mixed and may also be used.

  Fatty acid dimethylaminopropylamide having 8 or more carbon atoms and / or fatty acid diethylaminoethylamide is used for salt formation with lactic acid to increase the stability of the emulsion. Examples of fatty acids include caprylic acid, palmitic acid, myristic acid, Oleic acid, stearic acid, behenic acid and the like can be used. These are used in an amount of 0.1 to 20% by weight based on the polyglycerol fatty acid ester 10. If it is less than 0.1% by weight, the particle size of the emulsion is not sufficiently fine and the temperature stability is insufficient, and if it exceeds 20% by weight, the emulsion cannot be adjusted.

  Examples of the organic acid having 3 to 6 carbon atoms include lactic acid, citric acid, malic acid, succinic acid, tartaric acid, fumaric acid, propanoic acid, and butanoic acid. These organic acids having 3 to 6 carbon atoms are used to form a salt with fatty acid dimethylaminopropylamide and / or fatty acid diethylaminoethylamide having 8 or more carbon atoms to increase the stability of the O / W emulsion. The amount used is preferably 1.0% by weight to 20.0% by weight with respect to fatty acid dimethylaminopropylamide and / or fatty acid diethylaminoethylamide 10. If the amount is less than 1.0% by weight, no effect is observed, and even if the amount exceeds 20.0% by weight, no further effect is observed.

  In addition to the surfactant as an emulsifier, a small amount of fatty acid having an HLB of more than 8 may be used in combination with a polyglycerol fatty acid ester having 18 or more carbon atoms in order to stabilize the emulsion. , Decaglyceryl monostearate, decaglyceryl monoisostearate, decaglyceryl monooleate, decaglyceryl monolinoleate, decaglyceryl diisostearate, etc., especially decaglyceryl monooleate having a double bond in the fatty acid, mono Decaglyceryl linoleate is more preferable because of its better heat resistance. The preferred amount of use is 0.01% to 2.0% by weight, and a plurality of these may be used in combination.

As the colorant, dyes conventionally used in oil-based ballpoint pen inks can be used without limitation. As the dye, acid dyes, basic dyes, metal complex dyes, salt-forming dyes, azine dyes, anthraquinone dyes, phthalocyanine dyes, triphenylmethane dyes and the like can be used. Specifically, Bali First Yellow # 3104, Bali First Yellow # 3105, Bali First Yellow # 1105, Bali First Yellow AUM, Orient Spirit Black AB, Bali First Black # 3804, Bali First Black # 3806, Bali First Black # 1802, Bali First Black # 1805, Bali First Yellow # 1109, Bali First Orange # 2210, Bali First Red # 1320, Bali First Blue # 1605, Bali First Violet # 1701, Orient Oil Scarlet # 3 8. Nigrosine Base EX-BP (Oil Chemical Dye, Orient Chemical Co., Ltd.), Spiron Black GMH Special, Spiron Yellow C-2GH, Spiron Red C-GH, Spiron Red C-BH, Spiron Blue BPNH, Spiro Blue C-RH, Spiron Violet C-RH, S. P. T.A. Orange 6, S. P. T.A. Blue-111 (oil dye manufactured by Hodogaya Chemical Co., Ltd.), Rhodamine B base (CI. 45170B, oil dye manufactured by Sumitomo Chemical Co., Ltd.), Victoria Blue F4R, Nigrosine Base LK (Germany) Country, manufactured by BASF), methyl violet 2B base (manufactured by National Anil Div.), Etc. can be used.
These may be used alone or in combination. The O / W emulsion oily component must be at least an ink component obtained by dissolving an oil-soluble dye as a colorant in an organic solvent, and the amount of the oil-soluble dye added is from 5% to 50% by weight of the oily component, preferably 15 wt% or more and 40 wt% or less can be used. If the amount used is small, the handwriting density becomes thin when it is made into an emulsion, and if it is too large, the oil component part becomes unstable because it does not dissolve in the organic solvent, and the thermal stability of the emulsion may deteriorate.

  As a solvent that can be used for the emulsion oil component, an organic solvent that has been conventionally used in oil ballpoint pens and that can dissolve oil-soluble dyes and that does not substantially dissolve in water can be used. For example, ethylene glycol monoether solvents such as ethylene glycol monoethyl ether, ethylene glycol monohexyl ether, ethylene glycol mono 2-ethylhexyl ether, ethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, diethylene glycol monoethyl ether, diethylene glycol mono 2 -Diethylene glycol monoether solvents such as ethylhexyl ether, propylene glycol mononormal butyl ether, propylene glycol monophenyl ether, dipropylene glycol mononormal propyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monophenyl ether, tripropylene glycol monobutyl ether, Of and propylene glycol monomethyl ether solvent, benzyl alcohol, beta-phenylethyl alcohol, alcohol solvents such as α- methylbenzyl alcohol can be used. These may be used singly or in combination of two or more, and the blending amount is 1% by weight or more and 90% by weight or less based on the oil phase of the emulsion ink composition.

  Water is used as an essential component of the O / W emulsion ink. This water is preferably ion-exchanged water for the dissolution and stabilization of dyes and resins. Besides these essential components, conventionally known viscosity modifiers, dye dissolution accelerators, various resins and resin emulsions as fixing agents, antioxidants, ultraviolet absorbers, antiseptics, rust inhibitors, antifoaming agents, pH An adjusting agent and a lubricant for preventing ball seat wear and improving handwriting can be used as appropriate for both the oil phase and the water phase.

  In particular, it is desirable to mix a water-soluble organic solvent or a polyhydric alcohol with an aqueous component in order to prevent drying or freezing of the ink. Specifically, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, Water-soluble organic solvents such as polyethylene glycol, polypropylene glycol, 1,3-butylene glycol, thiodiethylene glycol, glycerin, diglycerin, triglycerin, and tetraglycerin, and polyhydric alcohols such as sorbitol, maltitol, and fructose can be used. Is preferably 50% by weight or less of the entire aqueous component.

  In order to impart desirable viscosity and rheological performance as a ballpoint pen ink, a high molecular weight polysaccharide, a water-soluble acrylic resin, an inorganic mineral thickener, and the like can be used as an aqueous component.

  The oil component containing the oil-soluble dye with respect to the total amount of the O / W emulsion ink is 10% by weight or more and 70% by weight or less, a polyglycerol fatty acid ester having an HLB of 8 or less, a fatty acid dimethylaminopropylamide having 8 or more carbon atoms, and / or Alternatively, the emulsifier component composed of fatty acid diethylaminoethylamide and an organic acid having 2 to 6 carbon atoms is preferably 0.1% by weight to 15% by weight, and the aqueous component is preferably 20% by weight to 75% by weight.

  The method of emulsification and dispersion for preparing the O / W emulsion ink is not particularly limited, and can be prepared by stirring at an appropriate temperature with a stirrer, homomixer, homogenizer or the like. In addition, high-pressure homogenizer treatment can be performed to make the prepared emulsion even finer, and filtration and centrifugation can be performed to make the emulsion particle size uniform and to remove insoluble matter.

Example 1
Spiron violet C-RH (colorant: manufactured by Hodogaya Chemical Co., Ltd.) 4.85% by weight
Spiro Yellow C-GNH (Colorant: Hodogaya Chemical Co., Ltd.) 3.30% by weight
Benzyl alcohol 11.85% by weight
Decaglyceryl pentastearate (HLB = 3.5) 12.00% by weight
Stearic acid dimethylaminopropylamide 2.40% by weight
Lactic acid 1.50% by weight
Glycerin 30.00% by weight
PVP K-90 (polyvinyl pyrrolidone: manufactured by ISP Japan Co., Ltd.) 0.70% by weight
Ion-exchanged water 33.40% by weight
Components other than the above glycerin, PVP K-90, and ion-exchanged water are heated and stirred at 80 ° C. for 3 hours, glycerin is added, and the mixture is further stirred at 80 ° C. for 1 hour to prepare A liquid. PVP K-90 and ion-exchanged water are stirred at 20 ° C. for 1 hour to prepare solution B. B liquid was added to A liquid at 80 degreeC, and it stirred with the magnetic stirrer for 45 minutes, Then, it cooled, stirring, and produced black emulsion ink.

Example 2
Spiro Yellow C-GNH (Colorant: Hodogaya Chemical Co., Ltd.) 2.45% by weight
Spiron Red C-GH (Coloring agent: Hodogaya Chemical Co., Ltd.) 3.15% by weight
Spiron Red C-BH (Coloring agent: Hodogaya Chemical Co., Ltd.) 4.00% by weight
Benzyl alcohol 5.40% by weight
Ethylene glycol monophenyl ether 15.00% by weight
Tetraglyceryl monostearate (HLB = 6.0) 4.50% by weight
Caprylic acid diethylaminoethylamide 4.50% by weight
Citric acid 0.50% by weight
Ethylene glycol 25.00% by weight
Kelzan AR (xanthan gum: manufactured by Sanki Co., Ltd.) 0.60% by weight
Ion-exchanged water 34.90% by weight
Components A other than the above ethylene glycol, Kelzan AR, and ion exchange water are heated and stirred at 80 ° C. for 1 hour to prepare A liquid. Ethylene glycol, Kelzan AR, and ion-exchanged water are stirred at 20 ° C. for 1 hour to prepare solution B. Liquid B was heated to 75 ° C. with a three-one motor and stirred while liquid A was added dropwise and stirred at 75 ° C. for 45 minutes, and then cooled with stirring to prepare a red emulsion ink.

Example 3
Spiron Red C-BH (Colorant: Hodogaya Chemical Co., Ltd.) 0.95% by weight
Neo Super Blue C-555 (Dye, Chuo Synthetic Chemical Co., Ltd.) 5.05% by weight
Ethylene glycol monophenyl ether 29.00% by weight
Decaglyceryl pentastearate (HLB = 3.5) 5.00% by weight
Stearic acid dimethylaminopropylamide 0.50% by weight
Propionic acid 1.00% by weight
Glycerin 40.00% by weight
Ion-exchanged water 19.50% by weight
Components other than the above glycerin and ion-exchanged water are heated and stirred at 80 ° C. for 3 hours to prepare Liquid A. Liquid A was added dropwise while stirring glycerin heated to 80 ° C. and ion-exchanged water with a homogenizer and treated for 5 minutes, and then cooled with stirring with a three-one motor to prepare a blue emulsion ink.

Example 4
Spiron Yellow C-GNH 2.86 wt%
Spiron Red C-BH 1.29 wt%
Ethylene glycol monophenyl ether 5.85% by weight
Decaglyceryl pentastearate (HLB = 3.5) 0.50% by weight
Myristic acid diethylaminoethylamide 1.00% by weight
Lactic acid 0.50% by weight
Glycerin 10.00% by weight
Ion-exchanged water 78.50% by weight
Components other than the above glycerin and ion-exchanged water are heated and stirred at 80 ° C. for 3 hours to prepare Liquid A. While stirring glycerin heated to 80 ° C. and ion-exchanged water with a homogenizer, the solution A was added dropwise and treated for 5 minutes, and further treated for 3 passes while cooling to 20 ° C. with a high-pressure homogenizer to produce an orange emulsion ink.

Example 5
Spiron Yellow C-GNH 2.86 wt%
Spiron Red C-BH 1.29 wt%
Ethylene glycol monophenyl ether 5.85% by weight
Decaglyceryl pentastearate (HLB = 3.5) 2.50% by weight
Decaglyceryl monooleate (HLB = 12.0) 1.00% by weight
Stearic acid diethylaminoethylamide 0.40% by weight
Lactic acid 0.20% by weight
Glycerin 10.00% by weight
Ion-exchanged water 76.10% by weight
Components A other than the above-mentioned decaglyceryl monooleate, glycerin and ion-exchanged water are heated and stirred at 80 ° C. for 3 hours to prepare solution A. Liquid A was added dropwise while stirring deaglyceryl monooleate heated to 80 ° C, glycerin and ion-exchanged water with a homogenizer, and treated for 5 minutes. Was made.

Example 6
Spiron Yellow C-GNH 2.86 wt%
Spiron Red C-BH 1.29 wt%
Ethylene glycol monophenyl ether 5.85% by weight
Decaglyceryl tristearate (HLB = 7.5) 0.50% by weight
Myristic acid diethylaminoethylamide 1.00% by weight
Lactic acid 0.50% by weight
Glycerin 10.00% by weight
Ion-exchanged water 78.50% by weight
Components other than the above glycerin and ion-exchanged water are heated and stirred at 80 ° C. for 3 hours to prepare Liquid A. While stirring glycerin heated to 80 ° C. and ion-exchanged water with a homogenizer, the solution A was added dropwise and treated for 5 minutes, and further treated for 3 passes while cooling to 20 ° C. with a high-pressure homogenizer to produce an orange emulsion ink.

Comparative Example 1
Spiron violet C-RH (colorant: manufactured by Hodogaya Chemical Co., Ltd.) 4.85% by weight
Spiro Yellow C-GNH (Colorant: Hodogaya Chemical Co., Ltd.) 3.30% by weight
Benzyl alcohol 11.85% by weight
Decaglyceryl pentastearate (HLB = 3.5) 12.00% by weight
Stearic acid dimethylaminopropylamide 2.40% by weight
PVP K-90 (polyvinyl pyrrolidone: manufactured by ISP Japan Co., Ltd.) 0.70% by weight
Ethylene glycol monophenyl ether 64.90% by weight
The above components were heated and stirred at 80 ° C. for 3 hours to dissolve the dye to prepare a black oil-based ink.

Comparative Example 2
A red emulsion ink was prepared in the same manner as in Example 2 except that the whole amount of stearic acid diethylaminoethylamide in Example 2 was replaced with benzyl alcohol.

Comparative Example 3
A blue emulsion ink was prepared in the same manner as in Example 3 except that decaglyceryl pentastearate was replaced with decaglyceryl monooleate (HLB = 12.0) in Example 3.

Comparative Example 4
A red emulsion ink was prepared in the same manner as in Example 2 except that the entire amount of citric acid in Example 2 was replaced with benzyl alcohol.

Comparative Example 5
Water Red 2 (CI Acid Red 87, manufactured by Orient Chemical Co., Ltd.) 4.0% by weight
Kelzan AR 0.2% by weight
Ethylene glycol 10.0% by weight
Triethanolamine 0.1% by weight
Ion exchange water 85.7% by weight
In the above components, Kelzan AR and water were stirred for 30 minutes with a lab mixer and dissolved uniformly to prepare a Kelzan aqueous solution. The remaining components were added thereto, and the mixture was further stirred for 2 hours to produce a black dye aqueous ink.

Comparative Example 6
Spiron Yellow C-GNH 2.86 wt%
Spiron Red C-BH 1.29 wt%
Dioctyl phthalate 3.63% by weight
Trioctyl phosphate 0.70% by weight
Poly n-butyl methacrylate 0.20% by weight
Dioctylsulfosuccinic acid (emulsifying dispersant) 0.50% by weight
Diethylene glycol 11.00% by weight
Urea (anti-drying agent) 5.00% by weight
Glycerin (solvent) 5.00% by weight
Surfynol 465 (acetylene surfactant, penetrant, manufactured by Nissin Chemical Industry Co., Ltd.)
0.50% by weight
Triethanolamine 0.80% by weight
Ion-exchanged water 68.52% by weight
Components A other than the above-mentioned diethylene glycol, urea, glycerin, Surfynol 465, triethanolamine, and ion-exchanged water are heated and stirred at 80 ° C. for 3 hours to prepare solution A. While stirring diethylene glycol, urea, glycerin, surfinol 465, triethanolamine, and ion-exchanged water heated to 80 ° C. with a homogenizer, the solution A was added dropwise for 5 minutes, and then further cooled to 20 ° C. with a high-pressure homogenizer. An orange emulsion ink was prepared by pass treatment.

Comparative Example 7
Spiron Yellow C-GNH 2.86 wt%
Spiron Red C-BH 1.29 wt%
Dipropylene glycol dibenzoate 15.00% by weight
Nikanol HP120 (xylene resin, manufactured by Hodogaya Chemical Co., Ltd.) 2.00% by weight
Glycerin 10.00% by weight
POE (10) distyrenated phenyl ether (emulsifier, HLB14) 0.50% by weight
POE (80) distyrenated phenyl ether (emulsifier, HLB19) 9.00% by weight
Kelzan AR (xanthan gum, thickener, manufactured by Sanki Co., Ltd.) 0.40% by weight
Ion exchange water 58.95% by weight
Among the above components, Spiron Yellow C-GNH, Spiron Red C-BH, Dipropylene Glycol Dibenzoate, and Nikanol HP120 are mixed and dissolved uniformly to obtain Liquid A. Next, the remaining components were stirred for 30 minutes with a lab mixer, and the solution uniformly dissolved was heated to 80 ° C., then A solution was added dropwise while stirring with a homogenizer, treated for 5 minutes, and further cooled to 20 ° C. with a high-pressure homogenizer. Then, an orange emulsion ink was prepared by performing 3 passes.

Particle size measurement The particle size was measured by measuring the particle size distribution of Examples 1 to 11 and Comparative Examples 2 to 3 as emulsion inks at 20 ° C using a laser diffraction particle size distribution analyzer SALD-7100 manufactured by Shimadzu Corporation. The median diameter was adopted as the average particle diameter.

Particle size measurement after heat aging at 50 ° C. 10 g of the inks of Examples 1 to 11 and Comparative Examples 2 to 3 which are emulsion inks are placed in a screw-cap glass bottle with a lid (19 × 70 mm, manufactured by Nidec Rika Glass Co., Ltd.). After being placed at 20 ° C. for 24 hours and then allowed to stand at 20 ° C. for 5 hours, the particle size after aging was measured in the same manner as the particle size measurement.

Preparation of test samples Knock-type ballpoint pens having a ballpoint pen tip holding each of the ink compositions for ballpoint pens obtained in Examples 1 to 6 and Comparative Examples 1 to 7 and holding a superhard ball having a diameter of 0.5 mm (knock) 1.7 g of the ink containing tube of the formula Energel, product code BLN75, manufactured by Pentel Co., Ltd. was filled into a test ballpoint pen sample.

Handwriting Water Resistance Test Each ball-point pen test sample is handwritten on JIS P3201 writing paper A by hand with 15 continuous circles having a diameter of about 2 cm twice, left for 1 hour, and then immersed in ion-exchanged water for 1 hour. Then, it took out from water and determined the degree of fading with a gray scale (JIS L-0804). The gray scale is from 1 to 5, and the larger the number, the smaller the density difference between the handwriting before and after the test, indicating water resistance.

Back-printing of handwriting Each ball-point pen test sample was handwritten on JIS P3201 writing paper A with 15 consecutive circles of about 2 cm in diameter twice and left for 1 day in an environment of 30 ° C and 60% RH. Was observed.
Those that did not exude ink at all ... ◎
The one that had only a slight oozing… ○
Clearly exuded …… ×
It was.
The results of each test are shown in Table 1.

50 for Examples 1 to 6 emulsified with polyglycerin fatty acid ester having HLB of 8 or less, fatty acid dimethylaminopropylamide and / or fatty acid diethylaminoethylamide having 8 or more carbon atoms, and organic acid having 3 to 6 carbon atoms. Even when heated at a temperature of 0 ° C., the emulsion particle diameter changes little and can be said to be a stable emulsion. In addition, the ink is excellent in water resistance and excellent in ink without handwriting.
In contrast, in Comparative Example 2 without an amide compound and Comparative Example 3 without an HLB of 8 or less and an amide compound, the emulsion was broken and the oil phase component and water were separated in a 50 ° C. heat test.
In Comparative Example 1, which is a simple oil-based ink that has not been emulsified, the ink penetrates to the back of the paper, so that the handwriting is turned off. In contrast, Comparative Example 5 is a normal water-based ink having no oil phase component, but in this case, since it is a water-soluble dye, the water resistance is very poor.
Furthermore, Comparative Example 6 emulsified with an anionic surfactant and Comparative Example 7 emulsified with a high HLB nonionic surfactant have poor water resistance.

  As described above in detail, since the O / W emulsion ink composition of the present invention has excellent temperature stability with little change in particle size even during heating and cooling cycles or heating at 50 ° C., it also has long-term room temperature stability over time. Well, it has good writing quality with excellent performance in water resistance and show-through of handwriting.

Claims (1)

An oil component comprising an oil-soluble dye as a colorant and an organic solvent for dissolving the dye, a polyglycerin fatty acid ester having an HLB of 8 or less, a fatty acid dimethylaminopropylamide having a carbon number of 8 or more, and / or a fatty acid diethylaminoethyl An O / W emulsion ink composition for ballpoint pens emulsified and dispersed in water with an amide and an organic acid having 3 to 6 carbon atoms.