JP5495592B2 - W / O type emulsion ink composition for writing instrument and writing instrument - Google Patents

Description

  The present invention relates to a W / O emulsion ink composition for a writing instrument and a writing instrument.

  As inks for writing instruments such as ballpoint pens, water-based inks and oil-based inks are generally used. In recent years, W / O emulsion inks in which water-based components are dispersed in oil-based components have been studied. In general, oil-based inks tend to have a heavy writing taste, and water-based inks tend to dry the writing lines slowly and easily stain the paper surface. On the other hand, the W / O type emulsion ink is attracting attention as an ink that satisfies both good writing quality and dryness of the writing line (see, for example, Patent Document 1).

Patent No. 3090425

  However, the W / O type emulsion ink has a problem that it is difficult to improve the ink ejection property at the start of writing, compared with the water-based ink and the oil-based ink. The W / O type emulsion ink described in Patent Document 1 also does not sufficiently improve that point, and it has not been possible to sufficiently suppress the occurrence of initial brush blur.

  The present invention has been made in view of the above circumstances, and provides a W / O emulsion ink composition for a writing instrument and a writing instrument using the same that can sufficiently suppress the initial brush blur at the beginning of writing. With the goal.

  In the present invention, a W / O emulsion ink composition for a writing instrument in which an aqueous component is dispersed in an oil component, the oil component contains a vegetable oil and a phosphate ester, and at least one of the oil component and the aqueous component is colored. A W / O type emulsion ink composition for a writing instrument containing an agent is provided.

  According to the W / O type emulsion ink composition for a writing instrument of the present invention, by including both the vegetable oil and the phosphate ester in the oil component, the ink can be smoothly discharged at the beginning of writing, The occurrence of fading can be sufficiently suppressed. In addition, since the ink is smoothly ejected, it is possible to suppress the occurrence of mottling during writing and to have excellent writing quality. Furthermore, since vegetable oil contains almost no VOC (volatile organic compound) component, there is no problem of air pollution and the like, and it is easy to decompose after disposal, and therefore has the advantage of being environmentally friendly.

  The vegetable oil in the W / O emulsion ink composition for writing instruments of the present invention preferably contains castor oil. When vegetable oil contains castor oil, blurring of the first brush can be further suppressed. Moreover, the emulsion stability of the W / O emulsion ink composition can be improved.

  In the W / O type emulsion ink composition for a writing instrument of the present invention, it is preferable that the colorant contained in the oil component contains an oil-soluble dye. As a result, oil droplets composed of an oil component are stabilized, and the emulsion stability of the ink composition can be further improved.

  It is preferable that content of the phosphate ester in the W / O type emulsion ink composition for writing instruments of this invention is 0.04-3 mass%. By containing the phosphoric acid ester in such a range, it becomes possible to further suppress the occurrence of blurring of the first brush.

  The vegetable oil content in the W / O emulsion ink composition for writing instruments of the present invention is preferably 0.9 to 10.0% by mass. By containing vegetable oil in such a range, it becomes possible to further suppress the occurrence of blurring of the first brush.

  Moreover, in this invention, the writing instrument which has the above-mentioned W / O type emulsion ink composition for writing instruments is provided. Since such a writing instrument has the W / O type emulsion ink composition having the above-described characteristics, the ink is smoothly ejected at the start of writing, and the occurrence of blurring of the first writing can be sufficiently suppressed. Further, since the ink is smoothly ejected, the occurrence of mottling during writing is suppressed and the writing quality is sufficiently excellent, and the wear resistance is also excellent.

  According to the present invention, it is possible to provide a W / O emulsion ink composition for a writing instrument and a writing instrument using the same that can sufficiently suppress the initial brush blur at the beginning of writing.

It is a schematic cross section which shows the ball-point pen which is one Embodiment of the writing instrument of this invention.

  In the following, preferred embodiments of the present invention will be described with reference to the drawings as the case may be.

  The W / O type emulsion ink composition for a writing instrument of this embodiment is a W / O type emulsion ink composition for a writing instrument in which an aqueous component is dispersed in an oily component, and the oily component contains vegetable oil and phosphate ester. And at least one of the oily component and the aqueous component contains a colorant. Hereinafter, each component constituting the W / O type emulsion ink composition of the present embodiment (hereinafter sometimes simply referred to as “ink composition”) will be described.

  The oily component contains vegetable oil. Vegetable oils include, for example, castor oil, avocado oil, safflower oil, rosehip oil, pistachio nut oil, macadamian nut oil, meadow foam oil, cranbear vicinica oil, sandalwood extract oil, yellowfin bark extract oil, barley extract oil Argan oil, jojoba oil, coconut oil, olive oil, cottonseed oil and the like can be used. These can be used individually by 1 type or in combination of 2 or more types.

  The vegetable oil preferably contains at least one selected from castor oil, pistachio nut oil, cranbearbicinica oil, and argan oil from the viewpoint of sufficiently suppressing the occurrence of blurring of the first brush. Moreover, vegetable oil can be made into the ink composition excellent in emulsification stability while further reducing a first-stroke blur by containing a castor oil.

  The content of the vegetable oil is preferably 1 to 10.0% by mass, more preferably 1 to 5.0% by mass, based on the total amount of the ink composition. When the content is less than 1% by mass, the effect of suppressing blurring of the first brush tends to be lower than when the content is within the above range, and when the content exceeds 10.0% by mass, the content There is a tendency that the emulsification stability of the ink composition is impaired as compared with the case where is within the above range. By setting the content of the vegetable oil to 1 to 5.0% by mass, it is possible to obtain an ink composition having excellent emulsification stability while sufficiently suppressing initial brush fading.

  The oil component contains a phosphate ester in addition to the vegetable oil described above. The phosphate ester can be obtained by dehydrating condensation of phosphoric acid and alcohol. In the present embodiment, a commercially available general phosphate ester can be used, and any of a phosphate monoester, a phosphate diester, and a phosphate triester can be used.

  The acid value of the phosphate ester is preferably 50 to 200, more preferably 60 to 150. By using a phosphoric acid ester having an acid value of 50 to 200, it is possible to obtain an ink composition having excellent abrasion resistance while further sufficiently suppressing the occurrence of blurring of the first brush.

  The pH of the phosphate ester is preferably 1-6, more preferably 1.5-3. By using a phosphoric acid ester having a pH in the above range, an ink composition having excellent wear resistance of a writing instrument tip can be obtained. Moreover, HLB of phosphate ester becomes like this. Preferably it is 4-14, More preferably, it is 5-13. By using a phosphoric acid ester having an HLB in the above range, it is possible to obtain an ink composition having further excellent emulsification stability.

  The content of the phosphate ester is preferably 0.05 to 3% by mass, more preferably 0.05 to 1% by mass, still more preferably 0.3 to 0.00%, based on the total amount of the ink composition. 9% by mass. When this content is less than 0.05% by mass, the effect of suppressing blurring of the first brush tends to be lower than when the content is within the above range. There is a tendency that the emulsification stability of the ink is impaired as compared with the case where is within the above range. By setting the content of the phosphate ester to 0.05 to 1% by mass, it is possible to obtain an ink composition excellent in emulsification stability while sufficiently suppressing initial brush fading. Moreover, by setting the content of the phosphoric acid ester to 0.05 to 0.9% by mass, it is possible to obtain an ink composition in which the generation of vacancies is further suppressed.

  The oil component preferably contains an oil-soluble dye as a colorant. As a result, oil droplets composed of an oil component are stabilized, and the emulsion stability of the ink composition can be further improved. Known oil-soluble dyes can be used without particular limitation. Examples of such oil-soluble dyes include direct dyes, acid dyes, and basic dyes. More specifically, for example, Spirit Black 61F, Bali First Violet 1701, Bali First Violet 1704, and Bali First Yellow. 1109, Bali First Blue 1605, Bali First Blue 1621, Bali First Blue 1623, Bali First Red 1320, Bali First Red 1360, Bali First Red 2320 (above, manufactured by Orient Chemical Industry Co., Ltd.), Eisen Spiron Black GMH Special, Eisen Spiro violet C-RH, Eisenspiron yellow C-GH new, Eisenspiron blue C-RH, Eisenspiron S. P. T.A. Blue-111, Eisenspiron S. P. T.A. Blue-121 (above, manufactured by Hodogaya Chemical Co., Ltd.) and the like. These can be used individually by 1 type or in combination of 2 or more types. By using an oil-soluble dye, the handwriting can be made dark and clear.

  The content of the oil-soluble dye is preferably 5.0 to 40.0% by mass, more preferably 10.0 to 30.0% by mass, and further preferably 20 to 20% by mass based on the total amount of the ink composition. 30% by mass. When the content is less than 5.0% by mass, the clarity of the handwriting tends to be lower than when the content is within the above range, and when the content exceeds 40.0% by mass, the content Compared with the case where the value is within the above range, the viscosity of the ink composition is increased, the writing quality is lowered, and the oil-soluble dye tends to be precipitated with time.

  The oil component may contain a component used as an oil component of a conventional ink composition in addition to the components described above. For example, the oil component may contain a polar solvent. As a polar solvent, the polar solvent used for an ink composition can be especially used without a restriction | limiting. Examples of such polar solvents include ethylene glycol monophenyl ether (phenyl glycol), propylene glycol monophenyl ether, propylene glycol dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, dipropylene glycol monobutyl ether, and tripropylene glycol monomethyl ether. Glycol ethers such as benzyl alcohol, ethylene glycol, triethylene glycol, propylene glycol, polyethylene glycol and the like. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the polar solvent is preferably 20.0 to 60.0 mass%, more preferably 30.0 to 50.0 mass%, based on the total amount of the ink composition. When the content is less than 20.0% by mass, the viscosity tends to be higher and the writing quality is impaired as compared with the case where the content is within the above range. When the content exceeds 60.0% by mass, Compared with the case where the content is within the above range, the emulsification stability of the ink tends to be impaired.

  The oil component may contain an additive. Examples of additives include viscosity modifiers (resins and the like), lubricants, pigments, antioxidants, and the like.

  Examples of the viscosity modifier include ketone resin, sulfoamide resin, maleic resin, xylene resin, amide resin, alkyd resin, phenol resin, rosin resin, terpene resin, butyral resin, and the like.

  As the lubricant, for example, a higher fatty acid such as oleic acid or a phosphate ester-based lubricant different from the phosphate ester can be used.

  Examples of the pigment include carbon black, insoluble azo, azo lake, condensed azo, diketopyrrolopyrrole, phthalocyanine, quinacridone, anthraquinone, dioxazine, indigo, thioindigo, quinophthalone, and selenium. Ordinary organic pigments such as isoindolinone can be used.

  In the ink composition of the present embodiment, the aqueous component preferably contains at least water and a colorant. Here, the content of water is preferably 5.0 to 30.0 mass%, more preferably 10.0 to 20.0 mass%, based on the total amount of the ink composition. When the content is less than 5.0% by mass, the writing taste tends to be lower than when the content is within the above range, and when the content exceeds 30.0% by mass, the content is the above. There is a tendency that the stability over time tends to be lower than in the case of being within the range.

  As the colorant, known ones can be used without particular limitation, and any of pigments and dyes can be used. Examples of the pigment include carbon black, insoluble azo series, azo lake series, condensed azo series, diketopyrrolopyrrole series, phthalocyanine series, quinacridone series, anthraquinone series, dioxazine series, indigo series, thioindigo series, quinophthalone series, selenium series, Common organic pigments such as isoindolinone can be used. These can be used individually by 1 type or in combination of 2 or more types. By using the pigment, the handwriting can be made dark and clear, and the light resistance of the handwriting can be made sufficient.

  Moreover, as dye, water-soluble dyes, such as a direct dye, an acidic dye, a basic dye, can be used, for example. Among these, as direct dyes, the color index number (hereinafter abbreviated as CI) Direct Black 17, 19, 19, 38, 154, C.I. I. Direct Yellow 1, 4, 12, 29, C.I. I. Direct Orange 6, 8, 26, 29, C.I. I. Direct Red 1, 2, 4, 13, C.I. I. Direct Blue 2, 6, 15, 15, 78, and the like. Examples of acidic dyes include C.I. I. Acid Black 2, 31 and C.I. I. Acid Yellow 3, 17, 23, 73, C.I. I. Acid Orange 10, C.I. I. Acid Red 13, 14, 18, 27, 52, 73, 87, 92, C.I. I. Acid Blue 1, 9, 74, 90 and the like. Examples of basic dyes include C.I. I. Basic Yellow 2, 3 and C.I. I. Basic Red 1, 2, 8, 8, C.I. I. Basic Violet 1, 3, 10, C.I. I. Basic Blue 5, 9, 26 and the like. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the colorant in the aqueous component is preferably 0.5 to 10.0% by mass, more preferably 1.0 to 5.0% by mass, based on the total amount of the ink composition. When this content is less than 0.5% by mass, the clarity of the writing line tends to be impaired as compared with the case where the content is within the above range. Compared with the case where the amount is within the above range, the writing taste and the emulsion stability of the ink composition tend to be impaired.

  When a pigment is contained as a colorant in the aqueous component, the aqueous component preferably further contains a pigment dispersant. Such a pigment dispersant is not particularly limited as long as it can disperse the pigment. For example, one kind of acrylic acid or an ester thereof, methacrylic acid or an ester thereof, maleic acid or an ester thereof is used alone. Water-soluble resins made by polymerizing with styrene, acrylonitrile, vinyl acetate, etc. or neutralized with alkali metals or amines to make them water-soluble, anionic surfactants, nonionic surfactants Agents and the like. Among these, a water-soluble resin is preferable, and specifically, a styrene-maleic acid copolymer is particularly preferable. These can be used individually by 1 type or in combination of 2 or more types. By using a pigment dispersant, it is possible to suppress sedimentation and aggregation of the pigment over time, and good stability over time can be obtained.

  The content of the pigment dispersant is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 3.0% by mass based on the total amount of the ink composition. When the content is less than 0.1% by mass, compared to the case where the content is within the above range, precipitation and aggregation of the pigment tends to occur with time, and 5.0% by mass. When it exceeds, when compared with the case where content is in the said range, there exists a tendency for the viscosity of an ink composition to become high and for a writing quality to fall.

  The aqueous component preferably further contains a lubricant. Examples of such lubricants include polyalkylene glycol derivatives, fatty acid salts, nonionic surfactants, and phosphate esters. The phosphate ester may be the same as or different from that contained in the oil component. Of these, fatty acid salts are preferred, and specifically potassium oleate is particularly preferred. These can be used individually by 1 type or in combination of 2 or more types. By using the lubricant, it is possible to further suppress the wear of the ball seat due to the pigment or the like.

  The content of the lubricant is preferably 0.1 to 5.0% by mass based on the total amount of the ink composition. When this content is less than 0.1% by mass, the wear suppression effect of the ball seat tends to be lower than when the content is within the above range, and when it exceeds 5.0% by mass. As compared with the case where the content is in the above range, the temporal stability of the ink composition tends to be lowered.

  The aqueous component may further contain other additives in addition to the above materials. Examples of such additives include rust preventives, antibacterial agents, humectants, pH adjusters and the like.

  Examples of the rust inhibitor include benzotriazole, tolyltriazole, octyl phosphate, imidazole, benzimidazole, and ethylenediaminetetraacetate.

  Examples of the antibacterial agent include sodium pentachlorophenol, sodium benzoate, potassium sorbate, sodium dehydroacetate, 1,2-benzisothiazolin-3-one, 2,4-thiazolylbenzimidazole, and paraoxybenzoic acid. Esters can be used.

  As the humectant, for example, urea, thiourea, ethyleneurea and the like can be used.

  Examples of the pH adjuster that can be used include triethanolamine, diethanolamine, monoethanolamine, aqueous ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, and sodium bicarbonate.

  The ink composition of this embodiment can be obtained as a W / O emulsion ink in which water droplets composed of an aqueous component are dispersed in an oily component by mixing the oily component and the aqueous component described above.

  In the ink composition of the present invention, the ratio of the content of the oil component to the aqueous component (oil component: aqueous component) is preferably in the range of 5: 5 to 8: 2 by mass ratio, and 6: 4 More preferably, it is in the range of ˜7: 3. When the ratio of the oil component is larger than the above range, it becomes a state close to that of a normal oil ink, and the writing quality is lowered, and the ink tends to cry out or the paper surface tends to be blurred. On the other hand, when the ratio of the oil component is smaller than the above range, the stability over time tends to be lowered and the handwriting tends to be blurred.

  The oily component and the aqueous component can be mixed using, for example, a stirrer such as a dissolver, a Henschel mixer, or a homomixer. Stirring conditions are not particularly limited. For example, by using a dissolver stirrer and stirring at a rotational speed of 100 to 1000 rpm for 30 to 180 minutes, water droplets composed of an aqueous component are uniformly dispersed in an oily component. Ink can be formed.

In addition, the ink composition of the present embodiment preferably uses a cone CP40, and the viscosity measured under conditions of a temperature of 25 ° C. and a shear rate of 0.75 s ⁻¹ is 300 to 2500 mPa · s, preferably 500 to 1500 mPa. -It is more preferable that it is s. If the viscosity is less than 300 mPa · s, leakage of the ink composition in a stationary state tends to occur, and the stability with time tends to decrease, and if it exceeds 2500 mPa · s, the writing quality tends to deteriorate. It is in.

  Next, the suitable embodiment of the writing instrument using the above-mentioned W / O type emulsion ink composition for writing instruments is described.

  FIG. 1 is a schematic cross-sectional view showing a ballpoint pen which is an embodiment of the writing instrument of the present invention. In the ballpoint pen 100 shown in FIG. 1, a W / O emulsion ink composition 12 for a writing instrument is filled in an ink storage tube 14. A ballpoint pen tip 20 is attached to one end side of the ink containing tube 14. The ball-point pen tip 20 includes a ball holder 24 and a ball 26, and is fixed to one end of the ink containing tube 14 by a joint 22. Further, in the ink containing tube 14, a backflow preventer 16 is accommodated in a state adjacent to the ink composition 12 on the side opposite to the ball-point pen tip 20 side of the ink composition 12. Here, the backflow prevention body 16 is arranged so that no gap is formed between the ink composition 12 and the backflow prevention body 16.

  In the ballpoint pen 100, the ink containing tube 14, the ballpoint pen tip 20, the ink composition 12, and the backflow preventer 16 constitute the core 10, and the core 10 is attached to the main body shaft 18, and further the main body shaft. A tail plug 28 having a vent hole is attached to the rear end of 18 (one end opposite to the ballpoint pen tip 20).

  Hereinafter, although the component of the ball-point pen 100 is demonstrated, the general structure used for a ball-point pen is applicable to structures other than the ink composition 12. FIG.

  As the ink containing tube 14, a resin made of polypropylene, polyethylene, polyethylene terephthalate, nylon, polyacetal, polycarbonate, or the like, or a metal can be used. Further, the shape of the ink containing tube 14 is not particularly limited, and may be a cylindrical shape, for example.

  The backflow prevention body 16 has a function of preventing the ink composition from flowing out (outflow prevention performance), a function of preventing the ink composition from drying up (sealing performance), and the like. Can be used without restriction. Such a backflow preventer 16 includes, for example, a base oil and a thickener. Examples of the base oil include mineral oil, polybutene, silicone oil, glycerin, polyalkylene glycol and the like. Moreover, as a thickener, a metal soap type thickener, an organic type thickener, an inorganic type thickener, etc. are mentioned.

  As the main body shaft 18 and the tail plug 28, for example, those made of a plastic material such as polypropylene can be used.

  As the joint 22, for example, a joint made of polypropylene, polyethylene, polyethylene terephthalate, nylon, polyacetal, polycarbonate or the like can be used.

  As the joint 22, the ball holder 24 and the ball 26 in the ballpoint pen tip 20, those used in a normal ballpoint pen can be used. The diameter of the ball 26 is preferably 0.3 to 1.2 mm.

  Since the ballpoint pen of this embodiment uses the ink composition which has the above-mentioned characteristic, it can fully suppress the blurring of the first brush and the occurrence of the blur. Further, the wear of the ball receiving portion of the ball 26 and the ball holder 24 can be sufficiently suppressed.

  The ballpoint pen 100 of the present embodiment having the above-described configuration can be manufactured by a normal ballpoint pen manufacturing method.

  The preferred embodiment of the ballpoint pen has been described above, but the ballpoint pen is not limited to the above embodiment. For example, the ballpoint pen of the present embodiment may not have the main body shaft 18, and the ink containing tube 14 may be the main body shaft as it is. Furthermore, the ballpoint pen according to the present embodiment is such that the ink composition 12 and the backflow prevention body 16 in the ink containing tube 14 are pressurized from the rear end (one end opposite to the ballpoint pen tip 20). It may have a pressure mechanism. Further, the ballpoint pen according to the present embodiment may not have the backflow prevention body 16.

  The writing instrument of the present invention is not limited to a ballpoint pen, and may be, for example, a marking pen including a writing pen, or a writing instrument using a valve mechanism in an ink discharge unit. The W / O type emulsion ink composition of the present invention can be used for various writing instruments as described above.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(Comparative Example 1-5, Example 1～8,10～ 12, Reference Example 9, 13-15)
The oily component and the aqueous component were separately prepared by blending the materials shown in Tables 1 and 2 below in the blending amounts (parts by mass) shown in the same table and mixing with a reciprocating rotary stirrer. The compositions of the aqueous gel inks in Tables 1 and 2 are shown in Table 3 below.

Next, using a dissolver stirrer, the aqueous component is added while stirring the oil component, and water droplets composed of the aqueous component are dispersed in the oil component by stirring for 1 hour at room temperature (25 ° C.) and rotation speed of 300 rpm W / O type emulsion ink compositions of Comparative Examples 1 to 5, Examples 1 to 8, 10 to 12, and Reference Examples 9 to 13 to 15 were obtained.

Details of each material in Table 1 and Table 2 are as follows.
Polyvinylpyrrolidone K-90 (trade name): Nippon Shokubai Co., Ltd., spinnability imparting agent.
VALIFAST VIOLET 1704 (trade name): Oil-soluble dye manufactured by Orient Chemical Industry Co., Ltd.
VALIFAST YELLOW 1109 (trade name): Oil-soluble dye manufactured by Orient Chemical Industry Co., Ltd.
SPILIT BLACK 61F (trade name): Oil-soluble dye manufactured by Orient Chemical Industry Co., Ltd.
Phosphanol RL-210 (trade name): manufactured by Toho Chemical Co., Ltd., phosphate ester surfactant, acid value: 95, pH: 5.4, HLB: 5.4.
-Phosphanol ML-220 (trade name): manufactured by Toho Chemical Co., Ltd., phosphate ester-based surfactant, acid value: 150, pH: 1.9, HLB: 12.5.
-Phosphanol RS-410 (trade name): manufactured by Toho Chemical Industry Co., Ltd., phosphate ester surfactant, acid value: 105, pH: 1.3, HLB: 9.0.
-Phosphanol GB-520 (trade name): manufactured by Toho Chemical Co., Ltd., phosphate ester surfactant.
Castor oil: Kou 1 (trade name), manufactured by Ito Oil Co., Ltd.
-Pistachio nut oil: manufactured by Nikko Chemicals.
・ Gran Bear Bishinica Oil: Nikko Chemicals
Argan oil: Nikko Chemicals

Details of each material in Table 3 are as follows.
-Xanthan gum: Monato gum GS (trade name), manufactured by Dainippon Pharmaceutical Co., Ltd.
Antirust agent: Colomin CB (trade name), manufactured by Kyrest Inc.
-Antibacterial agent: Slout 99N (trade name), manufactured by Nippon Enviro Chemicals.
-Potassium oleate: non-sar OK-1 (trade name), manufactured by NOF Corporation.
Pigment dispersant: SMA1000H Solution (trade name), manufactured by SARTOMER.

[Evaluation of faint blur]
Each example , comparative example and reference example were placed on a polypropylene cylindrical ink containing tube (inner diameter 4.0 mm) of a ballpoint pen similar to that shown in FIG. 1 having a ballpoint pen tip (ball diameter: 0.7 mm) at the tip. The ink composition obtained in 1 was accommodated. Next, 95% by mass of refined mineral oil and a thickener (metal soap, elastomer) on the side opposite to the ball-point pen tip in the ink containing tube (the rear end surface side of the ink composition) so as to be adjacent to the ink composition. A backflow prevention body consisting of 5% by mass was filled. Then, a tail plug was attached to the rear end of the main body shaft of the ballpoint pen to produce a ballpoint pen. In addition, eight ballpoint pens were produced for each example , comparative example, and reference example .

  About the produced ball-point pen, after writing with freehand once, it left still at room temperature (25 degreeC) for 1 hour. Thereafter, a straight line was written using a writing tester under the conditions of a writing angle of 70 °, a load of 100 g, and a writing speed of 4 m / min. The writing line at the beginning of writing was visually observed, and the distance (mm) of the writing line that had been faded was measured. The same measurement was performed on eight ballpoint pens, and the average value of each measurement distance was defined as the first brush. The results are shown in Tables 4 and 5.

[Bote evaluation]
A ballpoint pen was produced in the same manner as the above-mentioned “Evaluation of initial brush blur”. The produced ballpoint pen was attached to a writing tester, and a loop was written under the conditions of a writing angle of 70 °, a load of 200 g, and a writing speed of 4 m / min. The written lines were visually observed to evaluate the presence or absence of bots. “B” was rated as “A”, which was almost unpleasant and was larger than “A”. The results are shown in Tables 4 and 5.

[Evaluation of writing quality]
A ballpoint pen was produced in the same manner as the above-mentioned “Evaluation of initial brush blur”. Writing was performed freehand using the produced ballpoint pen, and the writing quality was evaluated based on the following evaluation criteria. The results are shown in Tables 4 and 5.
A: Smooth.
B: Smoothness is insufficient and heavy.

[Evaluation of emulsion stability]
The prepared ink composition was observed with an optical microscope (magnification: 200 times), and the emulsion stability was evaluated by observing the dispersion state. Observation with an optical microscope was performed twice immediately after preparation of the aqueous gel ink and after storage for 2 months at room temperature (25 ° C.), and evaluation was performed based on the following evaluation criteria.
A: The aqueous component is uniformly dispersed in the oil component, and the dispersion state is good.
B: The dispersion state of the aqueous component in the oil component is slightly non-uniform.
C: A non-uniform part is seen in the dispersion state of the aqueous component in the oil component.

In Examples 1 to 8 , 10 to 12, and Reference Examples 9 and 13 to 15 containing vegetable oil and phosphate ester, it was possible to suppress the initial brush fading more than Comparative Examples 1 to 5. According to the evaluation results of Examples 10 to 12, when the phosphate ester content was high, the amount of bottling tended to increase slightly. In the case of the ink composition of Reference Example 9 having a high castor oil content of about 9% by mass, a slightly separated phase was observed in the initial evaluation immediately after preparation. In addition, two months after the preparation of the ink composition, the aqueous components were combined to form large droplets.

In the ink composition of Example 12 having a high phosphate ester content of about 2.8% by mass, variation in the size of the aqueous component droplets was observed in the initial evaluation immediately after preparation. Two months after the preparation of the ink composition, the aqueous components were combined to form large droplets. In the ink compositions of Reference Examples 13 to 15 each using pistachio nut oil, granbe avicinica oil, and argan oil as vegetable oils, the aqueous component droplets were slightly aggregated in the initial evaluation immediately after preparation. Further, the droplets were similarly aggregated after being stored at room temperature for 2 months.

  DESCRIPTION OF SYMBOLS 10 ... Center core, 12 ... Ink composition, 14 ... Ink storage pipe, 16 ... Backflow prevention body, 18 ... Main body axis | shaft, 20 ... Ball-point pen tip, 22 ... Joint, 24 ... Ball holder, 26 ... Ball, 28 ... Tail plug 100 ... A ballpoint pen.

Claims (4)

A W / O type emulsion ink composition for a writing instrument in which an aqueous component is dispersed in an oil component,
The oily component contains vegetable oil and phosphate ester, and at least one of the oily component and the aqueous component contains a colorant;
The content of the vegetable oil Ri 0.9 to 5% by mass,
A W / O emulsion ink composition for a writing instrument, wherein the vegetable oil comprises castor oil . The colorant contained in the oil component comprises an oil-soluble dye, according to claim 1 for writing instruments W / O type emulsion ink composition. The W / O type emulsion ink composition for writing instruments of Claim 1 or 2 whose content of the said phosphate ester is 0.04-3 mass%. A writing instrument comprising the W / O emulsion ink composition for a writing instrument according to any one of claims 1 to 3 .

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