JP5243808B2 - 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 have a heavy writing feel, and water-based inks have slow drying of writing lines and easily stain the paper surface, while W / O emulsion inks satisfy both good writing taste and drying characteristics of writing lines. Has been proposed as an ink to be used (see, for example, Patent Document 1).
Japanese Patent No. 3090425

  However, even the conventional W / O type emulsion ink as described in Patent Document 1 has a problem in that the ink does not come out at the beginning of writing and the initial brush fading easily occurs.

  The present invention has been made in view of the above-described problems of the prior art, and can provide a W / O emulsion ink composition for a writing instrument that can sufficiently suppress the initial brush blur at the beginning of writing, and a writing instrument using the same. The purpose is to provide.

In order to achieve the above object, the present invention provides a W / O emulsion ink composition for a writing instrument in which an aqueous component is dispersed in an oil component, wherein the oil component contains vegetable oil and oleic acid, Provided is a W / O emulsion ink composition for a writing instrument, wherein at least one of an oily component and the aqueous component contains a colorant, and the vegetable oil contains at least one of castor oil and coconut oil .

  According to such a W / O type emulsion ink composition for a writing instrument, by including vegetable oil as an oily component, the ink can be discharged smoothly at the beginning of writing as compared with the case where no vegetable oil is contained. It is possible to sufficiently suppress the occurrence of fading. In addition, 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. Furthermore, in the W / O type emulsion ink composition for a writing instrument of the present invention, by using a combination of vegetable oil and oleic acid, the effect of suppressing the occurrence of blurring of the first brush is dramatically increased. The writing line is very smooth and you can write a wrinkle-free writing line.

  In the W / O type emulsion ink composition for a writing instrument of the present invention, the vegetable oil preferably contains castor oil. By including castor oil as a vegetable oil, it is possible to more efficiently and reliably suppress fading of the first brush.

  Furthermore, in the W / O type emulsion ink composition for a writing instrument of the present invention, the content of the vegetable oil is preferably 0.1 to 10.0% by mass based on the total amount of the ink composition. When the content of the vegetable oil is within the above range, it is possible to more efficiently and reliably suppress blurring of the first brush.

  The present invention also provides a writing instrument comprising the W / O emulsion ink composition for a writing instrument of the present invention. Such a writing instrument is provided with the W / O emulsion ink composition for a writing instrument of the present invention, so that the ink is smoothly drawn out at the start of writing, and the occurrence of the initial brush blur can be sufficiently suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the W / O type emulsion ink composition for writing instruments which can fully suppress the blur of the first writing in the beginning of writing, and a writing instrument can be provided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings as the case may be. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

  The W / O type emulsion ink composition for a writing instrument according to the present invention is a W / O type emulsion ink composition for a writing instrument in which an aqueous component is dispersed in an oil component, and the oil component contains vegetable oil and oleic acid. In addition, at least one of the oil component and the aqueous component contains a colorant. Hereinafter, each component constituting the ink composition will be described.

  The oil component contains at least vegetable oil. Although it is not particularly limited as a vegetable oil, 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. Among these, castor oil and coconut oil are preferable because they are particularly effective in suppressing blurring of the first brush, and are excellent in solubility in a polar solvent, which will be described later, contained in the oil component, and have good temporal stability. Therefore, castor oil is more preferable. These can be used individually by 1 type or in combination of 2 or more types.

  The content of the vegetable oil is preferably 0.1 to 10.0% by mass and more preferably 0.5 to 5.0% by mass based on the total amount of the ink composition. When this content is less than 0.1% by mass, compared to the case where the content is within the above range, the effect of suppressing the initial brush blur tends to decrease, and when it exceeds 10.0% by mass, Compared with the case where the content is within the above range, the emulsification stability of the ink tends to be impaired.

  In addition to the vegetable oil described above, the oil component further contains oleic acid. In some cases, oleic acid is contained in vegetable oil, but by adding oleic acid separately, the ink can be made very smoothly at the beginning of writing, and vegetable oil alone is used. Compared with, the blurring of the first brush can be more sufficiently suppressed.

  The content of oleic acid 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, the effect of suppressing blurring of the first brush tends to decrease, and when the content exceeds 5.0% by mass, Compared with the case where the content is within the above range, the emulsification stability of the ink tends to be impaired. Here, the content of oleic acid does not include the amount of oleic acid contained in the vegetable oil.

  Moreover, the oil component may contain the component used as an oil component of the conventional ink composition other than the vegetable oil and oleic acid mentioned 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 oil-soluble dye. Known oil-soluble dyes can be used without particular limitation. Examples of such oil-soluble dyes include direct dyes, acid dyes, basic dyes, and the like. More specifically, for example, Spirit Black 61F, Bali First Violet 1701, Bali First Violet 1704, 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.), Eisenspiron Black GMH Special, Eisenspiron 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 mass%, more preferably 10.0 to 30.0 mass%, based on the total amount of the ink composition. 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.

  Moreover, the oil component may further contain other additives in addition to the above components. Examples of such 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, higher fatty acids such as oleic acid, phosphate ester lubricants, and the like 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 invention, 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.

  Any known colorant can be used without particular limitation. As the colorant, any of a pigment and a dye 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 is preferably 0.5 to 10.0% by mass and 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 emulsification stability of the ink 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. The pigment dispersant is not particularly limited as long as it can disperse the pigment, and for example, one kind of acrylic acid or an ester thereof, methacrylic acid or an ester thereof, maleic acid or an ester thereof is polymerized alone. Or a water-soluble resin obtained by neutralizing a resin copolymerized with styrene, acrylonitrile, vinyl acetate or the like with an alkali metal or an amine, an anionic surfactant, a nonionic surfactant, etc. Is mentioned. Among these, a water-soluble resin is preferable, and specifically, a styrene-maleic acid copolymer is particularly preferable. These can be used alone or in combination of two or more. 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. Of these, fatty acid salts are preferred, and specifically potassium oleate is particularly preferred. These can be used alone or in combination of two or more. By using the lubricant, it is possible to 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 include triethanolamine, diethanolamine, monoethanolamine, aqueous ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate, sodium bicarbonate, and the like.

  The ink composition of the present invention 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.

The ink composition of the present invention preferably has a viscosity of 300 to 2500 mPa · s measured using a cone CP40 at a temperature of 25 ° C. and a shear rate of 0.75 s ⁻¹ , and 500 to 1500 mPa · s. More preferably, 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, an embodiment of the writing instrument of the present invention using the W / O type emulsion ink composition for a writing instrument of the present invention will be 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 of the ink containing tube 14. The ballpoint pen tip 20 is composed of a ball holder 24 and a ball 26, and is fixed to the ink containing tube 14 by a joint 22. In addition, a backflow preventer 16 is accommodated in the ink containing tube 14 on the side opposite to the ball-point pen tip 20 side of the ink composition 12 in a state adjacent to 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.

  In addition, when the ball-point pen tip 20 is directed downward, the viscosity of the backflow preventing body 16 and the viscosity between the ink composition 12 and the backflow preventing body 16 are prevented so that the backflow preventing body 16 does not settle in the ink composition 12. It is important to adjust the specific gravity difference. It is important that the backflow preventer 16 has a composition that is incompatible with the ink composition 12.

  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.

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

  As mentioned above, although suitable embodiment of the ball-point pen using the ink composition of this invention was described, a ball-point pen is not limited to the said embodiment. For example, the ballpoint pen according to the present invention 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 invention is such that the ink composition 12 and the backflow preventer 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 mechanism. Further, the ballpoint pen according to the present invention may not have the backflow prevention body 16.

  In addition, the ink composition of the present invention is not limited to those used for ballpoint pens, and can be used for marking pens including brush pens, writing instruments using a valve mechanism for the ink discharge part, and the like.

  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.

(Examples 1 , 2, 12, Reference Examples 3-11, 13 and Comparative Examples 1-15)
The oily component and the aqueous component were separately prepared by blending the materials shown in Table 1 below in the blending amounts (parts by mass) shown in the same table and mixing with a reciprocating rotary stirrer. The composition of the aqueous gel ink in Table 1 is shown in Table 2 below. Moreover, the composition of the ink and the kind of vegetable oil in each Example , Reference Example, and Comparative Example are shown in Tables 3 and 4 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. The obtained W / O type emulsion ink compositions of Examples , Reference Examples and Comparative Examples were obtained.

Details of each material in Table 1 are as follows.
Polyvinylpyrrolidone K-90 (trade name): Nippon Shokubai Co., Ltd., spinnability imparting agent.
SPILIT BLACK 61F (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.
VALIFAST VIOLET 1704 (trade name): Oil-soluble dye, manufactured by Orient Chemical Industry Co., Ltd.
Oleic acid: Lunac O-LL (trade name), manufactured by Kao Corporation, lubricant.

Details of each material in Table 2 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: Nonsar OK-1 (trade name), manufactured by NOF Corporation.
Pigment dispersant: SMA1000H Solution (trade name), manufactured by SARTOMER.

  Of the vegetable oils in Tables 3 and 4, castor oil Martok A and castor oil industry 1 were manufactured by Ito Oil Co., Ltd. In addition, refined avocado oil, safflower oil, rosehip oil, pistachio nut oil, macadamian nut oil, Meadow home oil, cranbear vicinica oil, argan oil, jojoba oil S, and TRIFAT C-24 (coconut oil) Used was made by Nikko Chemicals. Further, cottonseed oil manufactured by Wako Pure Chemical Industries, Ltd. was used.

[Evaluation of faint blur]
Examples , reference examples, and comparative examples are provided in 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). 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 , reference example, and comparative 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, and the distance (mm) at which the writing line was blurred at the beginning of writing was measured. The average value of 8 was obtained as the first brush blur. The results are shown in Tables 3 and 4.

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

Explanation of symbols

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 emulsion ink composition for a writing instrument in which an aqueous component is dispersed in an oil component,
W / O emulsion ink for writing instruments, wherein the oily component contains vegetable oil and oleic acid, at least one of the oily component and the aqueous component contains a colorant, and the vegetable oil contains at least one of castor oil and coconut oil. Composition.   The W / O emulsion ink composition for a writing instrument according to claim 1, wherein the vegetable oil contains castor oil.   The W / O type emulsion ink composition for writing implements of Claim 1 or 2 whose content of the said vegetable oil is 0.1-10.0 mass% on the basis of the ink composition whole quantity.   Writing instrument provided with the W / O type emulsion ink composition for writing instruments as described in any one of Claims 1-3.

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