Aqueous ink composition for writing instrument and writing instrument including the same

Abstract

To provide, by developing an ink for a writing instrument capable of obtaining calligraphy with gross of excellent metallic tone without using metal powder or pearl, an aqueous ink composition for writing instrument with high practicality applicable without generating inconvenience generated by application of high density material of the metal powder or pearl, and further without limiting a structure of the writing instrument and a writing instrument including the same.SOLUTION: A water-based ink composition made from water and dye, with a half-width of the maximum absorption wavelength of the ink in the range of 20 to 50, and a writing instrument incorporating it.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to an aqueous ink composition for a writing instrument and a writing instrument. The present invention further relates to an aqueous ink composition for a writing instrument that can produce handwriting with a metallic luster and a writing instrument incorporating the same. [Background technology]

[0002] Conventionally, aqueous ink compositions for writing instruments have been disclosed that contain, as a colorant, a metal powder such as aluminum or copper, or a pearl pigment coated with a base material such as glass or silica, and that produce handwriting with a metallic luster when written with the ink (see, for example, Patent Documents 1 to 3).

[0003] In the above-mentioned water-based ink, a colorant with a high specific gravity is used, so a thickening gelling agent (viscosity modifier) ​​is added to adjust the ink viscosity and maintain the dispersion state in the ink. Although it is easier to maintain the dispersion state when the ink viscosity is high, it becomes impossible to apply to marking pens and fountain pens, and in ballpoint pens, the ink tracking ability during writing is poor, line cracks and fading occur in the handwriting, and the pen tip tends to dry up. In addition, although the above-mentioned problems can be solved by lowering the ink viscosity, the dispersion state of the metal powder and pearl pigment cannot be maintained, and sedimentation and clogging of the pen tip occur. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2001-294795 A [Patent Document 2] JP 2000-309740 A [Patent Document 3] Japanese Patent Application Publication No. 11-148042 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention provides a writing instrument ink that can provide handwriting with an excellent metallic luster without using metal powder, pearl pigments, etc., thereby providing a highly practical aqueous ink composition for writing instruments that does not cause the above-mentioned problems caused by the use of high specific gravity materials such as metal powder and pearl pigments, and can be applied without limiting the structure of the writing instrument, and a writing instrument incorporating the same. [Means for solving the problem]

[0006] The aqueous ink composition for writing instruments of the present invention is an aqueous ink composition comprising at least water and a dye, and is required to have a half-width of the maximum absorption wavelength of the ink in the range of 20-50. Further, the dye is an acid dye, the acid dye is a triphenylmethane dye having a xanthene skeleton, and the dye is added in an amount of 10 to 45% by mass in the water-based ink. Furthermore, when handwriting is written on writing paper conforming to JIS P3201 at 20° C., the gloss level at an incidence angle of 60° is in the range of 1.5 to 20. A further feature is a writing instrument incorporating any one of the above-described water-based ink compositions for writing instruments. Effect of the Invention

[0007] The present invention has discovered that by adjusting the half-width of the maximum absorption wavelength of an aqueous ink containing water and a dye to the range of 20 to 50, it is possible to provide an aqueous ink composition for a writing instrument that can form handwriting having an excellent metallic luster without using metal powder or pearl pigments. This eliminates the need to adjust the dispersibility of the high-specific-gravity colorant, resulting in a highly practical aqueous ink composition for a writing instrument and a writing instrument that can be applied to all writing instruments of general-purpose structure and can produce handwriting that exhibits an excellent metallic luster without any problems. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The maximum absorption wavelength of the aqueous ink of the present invention is mainly due to the dye constituting the ink, and the dye to be used is not particularly limited as long as it is soluble or dispersible in an aqueous medium. For example, various dyes such as acid dyes, basic dyes, reactive dyes, direct dyes, disperse dyes and food dyes can be used alone or in combination of two or more kinds. In addition, general-purpose pigments and other colorants that are soluble or dispersible in aqueous media can also be used in combination. In particular, acid dyes are preferred because they exhibit the desired maximum absorption wavelength in aqueous inks and tend to produce metallic luster in handwriting. Therefore, when used in combination with other colorants, it is preferred to use acid dyes as the main colorant.

[0009] Specific examples of the acid dyes include Acid Blue Black 10B (CI Acid Black 1), Nigrosine (CI Acid Black 2), Suminol Milling Black 8BX (CI Acid Black 24), Kayanol Milling Black VLG (CI Acid Black 26), Suminol Fast Black BR ​​Concentrate (CI Acid Black 31), Mitsui Nylon Black GL (CI Acid Black 52), Aizen Opal Black WH Extra Concentrate (CI Acid Black 52), Sumiran Black WA (CI Acid Black 52), Ranil Black BG Extra Concentrate (CI Acid Black 107), Kayanol Milling Black TLB (CI Acid Black 109), Suminol Milling Black B (CI Acid Black 109), Kayanol Milling Black TLR (CI Acid Black 110), Aizen Opal Black New Concentrate (CI Acid Black 119), Water Black 187-L (CI Acid Black 154), Kayaku Acid Brilliant Flavin FF (CI Acid Yellow 7:1), Kayasil Yellow GG (CI Acid Black 110 ... Black 110), Kayaku Acid Brilliant Flavin FF (CI Acid Black 110), Kayaku Acid Brilliant Flavin FF (CI Acid 7), Xylene Light Yellow 2G 140% (same 17), Suminol Leveling Yellow NR (same 19), Daiwa Tartarazine (same 23), Kayak Tartarazine (same 23), Suminol Fast Yellow R (same 25), Diacid Light Yellow 2GP (same 29), Suminol Milling Yellow O (same 38), Suminol Milling Yellow MR (same 42), Water Yellow #6 (same 42), Kayanol Yellow NFG (same 49), Suminol Milling Yellow 3G (72), Suminol Fast Yellow G (61), Suminol Milling Yellow G (78), Kayanol Yellow N 5G (110), Suminol Milling Yellow 4G 200% (141), Kayanol Yellow NG (135), Kayanol Milling Yellow 5GW (127), Kayanol Milling Yellow 6GW (142), Sumitomo Fast Scarlet A (CIAcid Red 8), Kayaku Silk Scarlet (9), Solar Rubin Extra (14), Daiwa New Kokushin (18), Aizen Bonsaw RH (26), Daiwa Red No. 2 (27), Suminol Leveling Brilliant Red S3B (35), Kayasil Rubinol 3GS (37), Aizen Erythrosine (51), Kayaku Acid Rhodamine FB (52), Suminol Leveling Rubinol 3GP (57), Diacid Alizarin Rubinol F3G 200% (82), Aizen Eosin GH (87), Water Pink #2 (92), Aizen Acid Phloxine PB (92), Rose Bengal (94), Kayanol Milling Scar Red FGW (same 111), Kayanol Milling Rubin 3BW (same 129), Suminol Milling Brilliant Red 3BN Concentrate (same 131), Suminol Milling Brilliant Red BS (same 138), Aizen Opal Pink BH (same 186), Suminol Milling Brilliant Red B Concentrate (same 249), Kayaku Acid Brilliant Red 3BL (same 254), Kayaku Acid Brilliant Red BL (same 265), Kayanol Milling Red GW (same 276), Mitsui Acid Violet 6BN (CI Acid Violet 15), Mitsui Acid Violet BN (same 17), Water Violet #5 (same 49), Sumitomo Patent Pure Blue VX (CIAcid Blue 1), Water Blue #106 (same 1), Patent Blue AF (same 7), Water Blue #9 (same 9), Daiwa Blue No. 1 (same 9), Supranol Blue B (same 15), Orient Soluble Blue OBC (same 22), Suminol Leveling Blue 4GL (same 23), Mitsui Nylon Fast Blue G (same 25), Kayasil Blue AGG (same 40), Kayasil Blue BR (same 41), Mitsui Alizarin Sapphirol SE (same 43), Suminol Leveling Sky Blue R Extra Conc (same 62), Mitsui Nylon Fast Sky Blue B (same 78), Sumitomo Brilliant Indocyanine 6Bh / c (83), Sandran Cyanine N-6B350% (90), Water Blue #115 (90), Orient Soluble Blue OBB (93), Sumitomo Brilliant Blue 5G (103), Kayanol Milling Ultra Sky SE (112), Kayanol Milling Cyanine 5R (113), Aizen Opal Blue 2 GLH (158), Daiwa Guinea Green B (CI Acid Green 3), Acid Brilliant Milling Green B (9), Daiwa Green #70 (16), Kayanol Cyanine Green G (25), Suminol Milling Green G (27), etc. In particular, the effect is remarkable in triphenylmethane dyes.

[0010] Triphenylmethane acid dyes include CI Acid Violet 15, 16, 17, 19, 21, 23, 24, 25, 38, 49, 72, etc.; CI Acid Red 87, 92, 289 etc; CI Acid Blue 1, 3, 5, 7, 9, 11, 13, 15, 17, 22, 24, 26, 34, 48, 75, 83, 84, 86, 88, 90, 90:1, 91, 93, 99, 100, 103, 104, 108, 109, 110, 119, 123, 147, 206, 213, 269 etc; Examples include CI Acid Green 3, 5, 6, 7, 8, 9, 11, 13, 14, 15, 16, 18, and 22. Among these, triphenylmethane dyes having a xanthene skeleton are more useful because they have a particularly high visual effect.

[0011] The dye can be used in the ink composition in an amount of 1 to 50% by mass, and a range of 10 to 45% by mass is suitable for obtaining particularly clear handwriting with a metallic luster.

[0012] Furthermore, if necessary, a conventional water-soluble organic solvent that is compatible with water can also be used, such as ethanol, propanol, butanol, glycerin, sorbitol, triethanolamine, diethanolamine, monoethanolamine, ethylene glycol, diethylene glycol, thiodiethylene glycol, hexylene glycol, 1,3-butanediol, neoprene glycol, polyethylene glycol, propylene glycol, butylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether, propylene glycol monoethyl ether, 2-pyrrolidone, and N-methyl-2-pyrrolidone. The water-soluble organic solvents can be used alone or in combination of two or more kinds, and are used in an amount of 1 to 45% by mass, preferably 3 to 35% by mass, in the ink composition.

[0013] In addition, if necessary, inorganic salts such as sodium carbonate, sodium phosphate, sodium acetate, etc., pH adjusters such as organic basic compounds such as water-soluble amine compounds, rust inhibitors such as benzotriazole, tolyltriazole, saponin, etc., preservatives or antifungal agents such as carbolic acid, sodium salt of 1,2-benzthiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6-tetrachloro-4-(methylsulfonyl)pyridine, wetting agents such as urea, sorbitol, mannitol, sucrose, glucose, reduced starch hydrolysates, sodium pyrophosphate, etc., defoamers, and fluorine-based surfactants and nonionic surfactants which improve the penetration of the ink may be used. Furthermore, a lubricant can be added, and examples of the lubricant that can be used include metal soaps, polyalkylene glycol fatty acid esters, ethylene oxide-added cationic surfactants, phosphate ester surfactants, N-acyl amino acid surfactants, dicarboxylic acid surfactants, β-alanine surfactants, 2,5-dimercapto-1,3,4-thiadiazole, salts or oligomers thereof, 3-amino-5-mercapto-1,2,4-triazole, thiocarbamate, dimethyldithiocarbamate, α-lipoic acid, and condensates of N-acyl-L-glutamic acid and L-lysine, and salts thereof. In addition, by adding a thickening inhibitor such as an oligomer of N-vinyl-2-pyrrolidone, an oligomer of N-vinyl-2-piperidone, N-vinyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, ε-caprolactam, or an oligomer of N-vinyl-ε-caprolactam, the functionality in the retractable form can be improved.

[0014] In addition, one or more water-soluble resins such as alkyd resins, acrylic resins, styrene-maleic acid copolymers, cellulose derivatives, polyvinylpyrrolidone, polyvinyl alcohol, dextrin, etc. may be added, as long as the drying resistance is not impaired. One or more wetting agents such as urea, nonionic surfactants, sorbitol, mannitol, sucrose, glucose, reduced starch hydrolysates, sodium pyrophosphate, etc. may also be added.

[0015] A shear thinning agent may also be added to the water-based ink composition. As the shear thinning agent, a substance that is soluble or dispersible in water is effective, and examples thereof include xanthan gum, welan gum, zeta sea gum, diutan gum, macrohomopsis gum, succinoglycan (average molecular weight: about 1 to 8 million), which is an organic acid-modified heteropolysaccharide whose constituent monosaccharides are glucose and galactose, 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 and containing an alkyl ester of methacrylic acid as the main component, glucomannan, carbohydrates having gelling ability extracted from seaweed such as agar and carrageenin, poly N-vinyl-carboxylic acid amide crosslinked products, benzylidene sorbitol and benzylidene xylitol or derivatives thereof, crosslinkable acrylic acid polymers, inorganic fine particles, nonionic surfactants having an HLB value of 8 to 12, metal salts and amine salts of dialkyl sulfosuccinic acid, etc. Furthermore, N-alkyl-2-pyrrolidone and an anionic surfactant may be added in combination to the ink composition. The shear thinning agent can be used in the ink composition in an amount of 0.1 to 20% by mass.

[0016] The half width of the maximum absorption wavelength of the water-based ink composition is adjusted to be in the range of 20 to 50, and the water-based ink composition is configured as an ink for a writing instrument. The maximum absorption wavelength is determined by measuring the absorption spectrum of an ink diluted to a concentration within the measurement range of the device using a measuring device such as an ultraviolet-visible spectrophotometer Pharma Spec UV-1700 (manufactured by Shimadzu Corporation) or V-670 (manufactured by JASCO Corporation), and the maximum absorption wavelength of the ink is measured as the maximum absorption wavelength λmax. For the obtained maximum absorption wavelength, the width of the wavelength when the peak height at the wavelength peak point (central wavelength) is halved is the half-value width, which is an important index for obtaining handwriting with a metallic luster tone in the present invention. The wider the half-width (the more gentle the curve), the more blurred the color will appear, and the narrower the half-width (the sharper the curve), the sharper (more pure) the color will be. Therefore, by adjusting the ink composition so that the half-width of the maximum absorption wavelength is in the range of 20 to 50, preferably 20 to 45, an ink can be produced that can produce clear handwriting with a metallic luster.

[0017] Furthermore, by focusing on the glossiness of the handwriting, the handwriting can be made to have a more lustrous feel. Specifically, the glossiness of the handwriting when written on writing paper conforming to JIS P3201 at 20°C and at an incidence angle of 60° is adjusted to be in the range of 1.5 to 20, preferably 2.0 to 20. The gloss level can be measured, for example, by irradiating the handwriting on the writing paper with light from a light source positioned at an incidence angle of 60°, receiving the reflected light with a light receiver positioned at a reception angle of 60°, and measuring the intensity of the reflected light. Specifically, the gloss level is measured in accordance with ISO 2813 using a device such as a spectro 2 guide manufactured by BYK.

[0018] The aqueous ink composition for writing instruments of the present invention is filled into marking pens and ballpoint pens with fiber tips, felt tips, plastic tips, and ballpoint pen tips attached to the writing tip, as well as writing instruments (capped or retractable) using metal tips such as fountain pens and calligraphy pens. It can also be used for writing with a dip pen.

[0019] When loading ink into a marking pen, the structure and shape of the marking pen itself are not particularly limited, and examples of marking pens include a structure in which a marking pen tip (bullet type, chisel type, brush pen type, etc.) such as a fiber tip, felt tip, or plastic tip is attached to the writing tip, and ink is impregnated into an ink occlusion body made of a fiber bundle contained inside the barrel to supply ink to the writing tip; a structure in which ink is directly contained inside the barrel and a predetermined amount of ink is supplied to the writing tip through the intermediation of a comb-shaped ink flow rate adjustment member or an ink flow rate adjustment member made of a fiber bundle; and a structure in which ink is directly contained inside the barrel and a valve mechanism supplies a predetermined amount of ink to the writing tip. In addition to a pen with one pen tip, it may be a double-ended pen with pen tips of different thicknesses and shapes on both ends of the barrel. In the double-ended pen, one end may be a ballpoint pen.

[0020] When filling a ballpoint pen, the structure and shape of the ballpoint pen itself are not particularly limited, and examples include a structure in which ink is impregnated into an ink absorbing body made of a fiber bundle contained inside the barrel and ink is supplied to the writing tip, a structure in which ink is directly contained inside the barrel and an ink flow rate regulator in the shape of a comb groove or made of a fiber bundle is interposed, and a ballpoint pen having an ink reservoir tube filled with the ink composition inside the barrel, which ink reservoir tube is connected to a tip having a ball attached to its tip, and further having an ink backflow preventer in close contact with the end face of the ink.

[0021] The ink backflow preventive material may be either liquid or solid. Examples of the liquid ink backflow preventive material include non-volatile media such as polybutene and silicone oil. If desired, silica, aluminum silicate, etc. may be added to the media. As the solid ink backflow preventive material, a resin molded product can be mentioned. The liquid and solid ink backflow preventive materials can be used in combination. EXAMPLES

[0022] Examples will be described below, but the present invention is not limited to these examples. The compositions of the water-based inks for writing instruments of the Examples and Comparative Examples are shown in Table 1. The numerical values ​​of the compositions in the table indicate parts by mass.

[0023] [Table 1]

[0024] The contents of the ingredients in the table are explained according to the note numbers. (1) CI Acid Red 87 (acid dye with a triphenylmethane skeleton) (2) CI Acid Red 92 (acid dye with a triphenylmethane skeleton) (3) CI Acid Red 289 (acid dye with a triphenylmethane skeleton) (4) CI Acid Blue 9 (acid dye with a triphenylmethane skeleton) (5) CI Acid Blue 86 (acid dye with a triphenylmethane skeleton) (6) CI Acid Red 18 (acid dye without triphenylmethane skeleton) (7) CI Acid Yellow 9 (acid dye without triphenylmethane skeleton) (8) Phosphate ester surfactant, manufactured by Daiichi Kogyo Seiyaku Co., Ltd., trade name: Plysurf AL (9) Product name: Proxel XL-2, manufactured by Arcade Japan

[0025] Preparation of writing instrument ink The raw materials were mixed in the amounts described in the Examples and Comparative Examples, stirred and dissolved at 20° C. for 1 hour, and then filtered to obtain a water-based ink composition for writing instruments.

[0026] Making a marking pen Each of the obtained ink compositions was poured into the ink reservoir of a commercially available marking pen (SW-VSP, manufactured by Pilot Corporation) and assembled to obtain a marking pen.

[0027] Making a fountain pen Each of the obtained ink compositions was contained in an ink cartridge (IRF12S, manufactured by Pilot Corporation), and the ink cartridge was assembled into a commercially available fountain pen (FKA1SR, manufactured by Pilot Corporation) to obtain a fountain pen.

[0028] The following tests were carried out using each of the resulting ink compositions and writing implements. The half width of the maximum absorption wavelength was determined by diluting each ink composition 10,000 times and measuring the absorbance using a JASCO V-670. Written Exam A Using each marking pen, 12 spiral circles were handwritten in succession on JIS P3201 writing paper A at 20° C., and the condition of the handwriting was visually confirmed. Furthermore, the gloss of each handwriting was measured at an incidence angle of 60° in accordance with ISO 2813 using a BYK "spectro 2 guide." Written Exam B Using each fountain pen, a 3 cm square frame was handwritten on JIS P3201 writing paper A and black paper at 20°C, and the condition of the handwriting was visually confirmed. The results of each test are shown below.

[0029] [Table 2]

[0030] The symbols in the table are evaluated as follows: Written Exam A ◯: Good handwriting was obtained, and handwriting with a high luminance and metallic luster was visually recognized. ×: No metallic luster was observed in the handwriting. Written Exam B ◯: Good handwriting was obtained, and handwriting with a high luminance and metallic luster was visible on all papers. ×: No metallic luster was observed in the handwriting.

Claims

1. The aqueous ink composition for a writing instrument is composed of at least water and a dye, and has a half-width of the maximum absorption wavelength of the ink in the range of 20 to 50.

2. 2. The water-based ink composition for writing instruments according to claim 1, wherein said dye is an acid dye.

3. 3. The aqueous ink composition for a writing instrument according to claim 2, wherein the acid dye is a triphenylmethane dye having a xanthene skeleton.

4. 4. The aqueous ink composition for a writing instrument according to claim 1, wherein the dye is added in an amount of 10 to 45% by mass in the aqueous ink.

5. 2. The water-based ink composition for writing instruments according to claim 1, wherein the gloss of handwriting at an incidence angle of 60° when written on writing paper conforming to JIS P3201 at 20° C. is in the range of 1.5 to 20.

6. A writing instrument incorporating the aqueous ink composition for writing instruments according to any one of claims 1 to 5.

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