JP6104727B2 - Water-based ink composition for writing instruments and writing instrument incorporating the same - Google Patents

Description

  The present invention relates to a water-based ink composition for writing instruments. Furthermore, the present invention relates to a water-based ink composition for a writing instrument that exhibits a pastel hue and a writing instrument incorporating the same.

Conventionally, when preparing a pastel-colored water-based ink, the color is adjusted using a combination of titanium oxide and a colored pigment. However, since titanium oxide has a large specific gravity and easily settles, the ink is added with a thickener. A technique for suppressing sedimentation by increasing the viscosity is used. Among them, a technique is disclosed in which succinoglycan, which is a high molecular polysaccharide, is used to adjust ink viscosity and suppress titanium oxide precipitation (see, for example, Patent Document 1).
In the above technique, although precipitation of titanium oxide can be suppressed in the ink immediately after production, the colored pigment and succinoglycan aggregate with time, and color separation of titanium oxide and colored pigment is performed on the handwriting. May occur or cause poor writing.

  In addition, in order to solve the above-mentioned problems, a technique is disclosed in which particles in which titanium oxide and a colored pigment are encapsulated in microcapsules or composite particles in which titanium oxide and a colored pigment are dispersed in a polymer resin are used as a colorant. (For example, see Patent Documents 2 and 3). In the above technique, since titanium oxide and a colored pigment are present in a single particle, the above-described color separation can be suppressed, but since the particle becomes large, sedimentation occurs with time, and an ink discharge path such as a ballpoint pen. When applied to a small writing instrument, writing failure may occur due to clogging at the pen tip. Further, since the colored pigment is coated with the microcapsule or the polymer resin, the color is blurred and it is difficult to obtain a beautiful pastel color.

JP-A-8-113752 JP 2006-28370 A JP 2006-28371 A

  The present invention relates to a pen formed when applying to a writing instrument such as a ballpoint pen or the like, which causes aggregation and sedimentation of a colorant, color separation of titanium oxide and a colored pigment, which occurs when a pastel color ink is constituted. The present invention provides a water-based ink composition for a writing instrument and a writing instrument incorporating the same, in which a beautiful pastel handwriting can be obtained without causing problems such as poor writing due to clogging.

The water-based ink composition for a writing instrument according to the present invention comprises a white inorganic particle powder whose particle surface is coated with a paste and an organic pigment is adhered to the coating portion, a dispersion stabilizer, and a surfactant. And water.
Furthermore, it is required that it contains hollow resin particles and a thickener.
Furthermore, the writing instrument formed by incorporating the water-based ink composition for a writing instrument is required.

  According to the present invention, a pastel color handwriting with a beautiful hue can be obtained without causing problems such as coagulation sedimentation of the colorant and color separation between the titanium oxide and the colored pigment, which have occurred when constituting a pastel color ink. A water-based ink that can be formed. In addition, it is possible to suppress writing defects due to clogging at the pen tip that occurs when applied to a writing instrument having a small ink discharge path such as a ballpoint pen.

  In the water-based ink composition of the present invention, the particle surface of the white inorganic particle powder is coated with a paste, and the colored particles having an organic pigment attached to the coated portion are used as a coloring material, thereby providing excellent performance as a writing instrument ink. This makes it possible to form beautiful pastel handwriting.

Examples of white inorganic particles constituting the colored particles include white pigments such as titanium dioxide and zinc oxide, pearl pigments such as titanium mica and muscovite, silica fine particles such as silica powder, white carbon, fine powder silicic acid, diatomaceous earth, and clay, Examples include extender pigments such as calcium carbonate, barium sulfate, alumina white, talc, and transparent titanium oxide.
When the white pigment is used as the material, a vivid color can be expressed with a high hiding power. When the pearl pigment is used, a pearly luster is obtained. When the pearl pigment or the extender pigment is used. Since transparency is obtained, various selections can be made according to the desired color tone.

The particle shape of the white inorganic particles may be any shape such as spherical shape, granular shape, polyhedron shape, needle shape, spindle shape, rice grain shape, flake shape, scale shape and plate shape.
Moreover, as a particle | grain size, an average particle diameter is 0.009-9.95 micrometers, Preferably it is the range of 0.019-8.95 micrometers. When the average particle diameter exceeds 9.95 μm, the resulting colored particles become coarse particles, which is not preferable because the coloring power is reduced.

  As the paste, anything may be used as long as an organic pigment can be attached to the surface of white inorganic particles, preferably an organosilicon compound such as alkoxysilane, fluoroalkylsilane, or polysiloxane, silane, or titanate. 1 type or 2 types or more of various coupling agents, oligomers, or polymer compounds of the system, aluminate and zirconate. In consideration of the adhesion strength of the organic pigment to the surface of the white inorganic particles, more preferably various types of organosilicon compounds such as alkoxysilane, fluoroalkylsilane, and polysiloxane, silane, titanate, aluminate, and zirconate It is a coupling agent.

Specific examples of alkoxysilanes include methyltriethoxysilane, dimethyldiethoxysilane, phenyltriethoxysilane, diphenyldiethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, and isobutyltrimethoxysilane. And decyltrimethoxysilane.
Specific examples of the fluoroalkylsilane include trifluoropropyltrimethoxysilane, tridecafluorooctyltrimethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecafluorodecylmethyldimethoxysilane, trifluoropropylethoxysilane, and tridecafluoro. Examples include octyltriethoxysilane, heptadecafluorodecyltriethoxysilane, and the like.

  Examples of the organic pigments include red organic pigments, blue organic pigments, yellow organic pigments, green organic pigments, orange organic pigments, brown organic pigments, which are generally used as colorants in paints and resin compositions. Various organic pigments such as purple organic pigments can be used.

As the red organic pigment, quinacridone pigments such as quinacridone red, azo pigments such as permanent red, condensed azo pigments such as condensed azo red, and perylene pigments such as perylene red can be used. As the blue organic pigment, phthalocyanine pigments such as metal-free phthalocyanine blue, phthalocyanine blue, and fast sky blue can be used. As the yellow organic pigment, monoazo pigments such as Hansa Yellow, disazo pigments such as benzidine yellow and permanent yellow, and condensed azo pigments such as condensed azo yellow can be used. As the green pigment, a phthalocyanine pigment such as phthalocyanine green can be used.
In order to obtain a desired hue, the above organic pigments may be mixed and used. Further, two or more kinds of similar colors may be used according to the required hue and characteristics.

The adhesion amount of the organic pigment is 1 to 500 parts by weight with respect to 100 parts by weight of the white inorganic particle powder.
When the amount is less than 1 part by weight and when it exceeds 500 parts by weight, it is difficult to form the colored particles. Preferably it is 3-400 weight part, More preferably, it is 5-300 weight part.

The colored particles have an average particle size of 0.01 to 10 μm, preferably 0.02 to 9 μm. When the average particle diameter exceeds 10 μm, when accommodated in a ballpoint pen for practical use, the gap between the ball and the ball holding portion is blocked to cause clogging, and the ink ejection property is easily impaired. On the other hand, when it is less than 0.01 μm, it is difficult to show a high density hue.
The particle diameter is measured using a laser diffraction / scattering particle size distribution measuring apparatus (manufactured by Horiba, Ltd .; LA-300), and the average particle diameter (median diameter) is calculated based on the numerical value. .

Furthermore, among the colored particles, among the dyes and pigments that are general-purpose coloring components for writing instruments, those that are stable in the composition can be selected and added to the ink. In that case, a clearer hue can be expressed.
As the dye, an acid dye, a basic dye, a direct dye, and the like can be used. As the pigment, in addition to an inorganic pigment such as carbon black and ultramarine blue, and an organic pigment such as copper phthalocyanine blue and benzidine yellow, Water-dispersed pigment products that are finely and stably dispersed in an aqueous medium using a surfactant or a resin are used. Furthermore, it is selected from synthetic resin fine particulate fluorescent pigments in which various fluorescent dyes are solid-solved in a resin matrix, white pigments such as titanium oxide, metal powders such as aluminum, natural mica, synthetic mica, alumina, and glass pieces. Pearl pigments in which the surface of the core material is coated with a metal oxide such as titanium dioxide, cholesteric liquid crystal type glitter pigments, and the like can also be used.

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

The colorant containing the colored particles can be added in the range of 5 to 30% by weight, preferably 10 to 25% by weight, based on the total amount of the ink composition.
If it is less than 5% by weight, the color tone of the handwriting is thin, and if it exceeds 30% by weight, the amount of solid content in the composition is large and there is a risk of causing problems during writing, so no further addition is required.

Further, a dispersion stabilizer is used in order to further stabilize the colored particles in the ink in a long-term dispersion state.
As the dispersion stabilizer, dispersion components conventionally used in writing instrument inks can be used, and amine surfactants, amphoteric surfactants, polymer surfactants, anionic surfactants, nonionic surfactants, and cationic surfactants. Surfactant etc. are mentioned. Furthermore, polyamide resin, polyurethane resin, polyester resin, epoxy resin, melamine resin, phenol resin, silicone resin, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, polystyrene, acrylic acid resin, maleic acid resin Arabic gum, cellulose, dextran, casein and the like, and derivatives thereof, and copolymers of the above-described resins.

Furthermore, when the water-based ink composition of the present invention is filled in a ballpoint pen, hollow resin particles can be blended. The hollow resin particles have the effect of lowering the average specific gravity of the solid content in the ink composition and improving the dispersion stability of the colored particles. In particular, in order to obtain a sufficient dispersion effect, the hollow resin particles preferably have an average particle size in the range of 0.2 to 5.0 μm, and 5.0 to 20.0% by weight in the total amount of the ink composition. Formulated in a range. If it is less than 5.0% by weight, the dispersion effect is insufficient, and if it exceeds 20.0% by weight, the viscosity of the ink becomes too high, which is not preferable.
Examples of the hollow resin particles include SX863 (A), SX864 (B), SX865 (B), SX866 (A), SX866 (B), SX8782 (D), AE865 (manufactured by JSR Corporation), Nipol MH5055. , Nipol MH5055A, Nipol MH8055 [above, manufactured by Nippon Zeon Co., Ltd.], Ropaque OP-84J, Ropaque Ultra E, Ropaque HP-1055 [above, manufactured by Rohm and Haas] and the like.

Furthermore, a conventional general-purpose water-soluble organic solvent compatible with water can be used in the ink composition as necessary. Specifically, ethanol, propanol, butanol, glycerin, sorbitol, triethanolamine, diethanolamine, monoethanolamine, ethylene glycol, diethylene glycol, thiodiethylene glycol, polyethylene glycol, propylene glycol, butylene glycol, ethylene glycol monomethyl ether, ethylene glycol mono Examples include ethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, sulfolane, 2-pyrrolidone, and N-methyl-2-pyrrolidone.
In addition, the said water-soluble organic solvent can be used 1 type or in combination of 2 or more types, and is used in 2 to 60 weight%, Preferably it is 5 to 35 weight%.

In addition, if necessary, pH adjusters such as inorganic salts such as sodium carbonate, sodium phosphate and sodium acetate, organic basic compounds such as water-soluble amine compounds, rust preventives such as benzotriazole, tolyltriazole and saponin , Carboxylic acid, sodium salt of 1,2-benzthiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6-tetrachloro-4- (methylsulfonyl) Preservatives or antifungal agents such as pyridine, urea, sorbit, mannitol, sucrose, glucose, reduced starch hydrolysates, wetting agents such as sodium pyrophosphate, antifoaming agents, fluorine-based interfaces that improve ink permeability An activator or a nonionic surfactant may be used.
Further, a lubricant can be added, such as metal soap, polyalkylene glycol fatty acid ester, ethylene oxide addition type cationic surfactant, phosphate ester type surfactant, N-acyl amino acid type surfactant, dicarboxylic acid type surfactant. , Β-alanine type surfactant, 2,5-dimercapto-1,3,4-thiadiazole and its salts and oligomers, 3-amino-5-mercapto-1,2,4-triazole, thiocarbamate, dimethyl A dithiocarbamate, α-lipoic acid, a condensate of N-acyl-L-glutamic acid and L-lysine, a salt thereof, or the like is used.
N-vinyl-2-pyrrolidone oligomer, N-vinyl-2-piperidone oligomer, N-vinyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, ε-caprolactam, N-vinyl-ε-caprolactam oligomer, etc. By adding a thickening inhibitor, it is possible to enhance the function in the intruding form.

  In addition, one or two or more water-soluble resins such as alkyd resin, acrylic resin, styrene maleic acid copolymer, cellulose derivative, polyvinyl pyrrolidone, polyvinyl alcohol, dextrin may be added in a category that does not hinder drying resistance, urea, One or more wetting agents such as nonionic surfactants, sorbitol, mannitol, sucrose, glucose, reduced starch hydrolyzate and sodium pyrophosphate can be added.

Furthermore, by adding a thickening agent, it is possible to suppress sedimentation of colored particles during long-term high-temperature storage and to suppress bleeding of handwriting. Further, when the ballpoint pen is filled with the ink composition, it is possible to prevent ink leakage from the gap between the ball and the chip when not in use, or to prevent ink backflow when the writing tip is left facing upward.
A general-purpose compound is used as the thickener, and examples thereof include polyvinylpyrrolidone, polyurethane, acrylic resin, polyamide amine salt, polyether, EVA copolymer, carboxylic acid copolymer, and the like.
Also applicable are those that exhibit shear thinning, such as xanthan gum, welan gum, zetasy gum, dieuthan gum, macrohomopsis gum, and succinoglycan (mean succinoglycan), whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose A molecular weight of about 100 to 8 million), guar gum, locust bean gum and derivatives thereof, hydroxyethyl cellulose, alginic acid alkyl esters, polymers having a molecular weight of 100,000 to 150,000 based on alkyl esters of methacrylic acid, glucomannan, agar Carbohydrate having gelation ability extracted from seaweed such as carrageenin, poly N-vinyl-carboxylic acid amide cross-linked product, benzylidene sorbitol and benzylidene xylitol or their derivatives, cross-linkable acrylic acid polymer, inorganic fine particles, H Nonionic surfactants B values 8 to 12, the metal salts and amine salts of dialkyl sulfosuccinic acid and the like. Furthermore, N-alkyl-2-pyrrolidone and an anionic surfactant may be used in combination in the ink composition.
The thickener can be used in the range of 0.1 to 20% by weight in the ink composition.

  The water-based ink composition for a writing instrument of the present invention is filled in a marking pen or a ballpoint pen having a fiber tip, a felt tip, a plastic tip or a ballpoint tip attached to the tip of the writing. The marking pen and the ballpoint pen have a cap type with a cap that covers the pen tip, a knock type, a rotary type, a slide type, etc. It may be.

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

  When filling the ball-point pen, the structure and shape of the ball-point pen itself are not particularly limited. For example, an ink occlusion body composed of a fiber bundle housed in the shaft tube is impregnated with ink and supplied to the writing tip. Structure, ink is stored directly inside the shaft cylinder, and there is an ink storage tube filled with the ink composition in the shaft cylinder, with a comb groove-shaped ink flow control member and an ink flow control member consisting of fiber bundles interposed The ink storage tube communicates with a chip having a ball attached to the tip, and a ballpoint pen having a structure in which a liquid stopper for backflow prevention is in close contact with the end surface of the ink. A solid stopper can be used together with the liquid stopper.

  Although the composition of the ink used as an Example is shown in the following table | surfaces, this invention is not limited to these Examples. In addition, the numerical value of a composition in a table | surface shows a weight part. Moreover, each average particle diameter used Horiba Seisakusho laser type particle size distribution measuring machine LA-300, and the median diameter was made into the average particle diameter.

The contents of the raw materials in the table will be described along the note numbers.
(1) Colored particles (average particle size 0.3 μm) formed by coating titanium oxide with methyltriethoxysilane serving as a paste and attaching a red pigment
(2) Colored particles (average particle size 0.3 μm) obtained by coating titanium oxide with γ-aminopropyltriethoxysilane as a paste and attaching a phthalocyanine blue pigment
(3) Dainichi Seika Kogyo Co., Ltd., trade name: WA-S Color Orange (7% pigment content aqueous solution)
(4) Titanium oxide (average particle size 0.5 μm), red pigment, normal paraffin (specific gravity 0.745), stearic acid, tall oil are mixed and stirred, and then dispersed with an ultrasonic disperser for inclusion in microcapsule particles A dispersion was prepared. Thereafter, a 5% by weight gelatin aqueous solution and a 5% by weight gum arabic aqueous solution are mixed with stirring, and the particle dispersion is stirred and added to an aqueous solution whose pH is adjusted to 9.0 with an aqueous sodium hydroxide solution. After the treatment with a microbe isolated from a mixture obtained by lowering the pH to 4.0 using an aqueous acetic acid solution to form gelatin / gum arabic coacervate and adding a formalin 35% aqueous solution to cause a curing reaction. Capsule (average particle size 15μm)
(5) Composite particles (average particle size 15 μm) obtained by dispersing titanium oxide (average particle size 0.3 μm) and blue pigment in a dissolved low density polypropylene resin, crushing and classifying the solidified material
(6) Product name: DISPER BYK-2015, manufactured by Big Chemie Japan Co., Ltd.
(7) Rohm and Haas Co., Ltd., trade name: Ropeke Ultra E (solid content 30%)
(8) Product name: Bandis G-25K manufactured by Harima Kasei Co., Ltd.
(9) Daiichi Kogyo Seiyaku Co., Ltd., trade name: F6312
(10) Product name: Nikkor PBC-44 manufactured by Nikko Chemicals Co., Ltd.
(11) Arch Chemicals Japan, trade name: Proxel XL-2

Preparation of ball-point pen ink The raw materials excluding succinoglycan were mixed in the blending amounts of Examples 1 and 2 and Comparative Examples 1 and 2, and stirred at 400 ° C. with a disper at 20 ° C. for 1 hour, and then succinoglycan was added. The mixture was further stirred for 1 hour to obtain a ballpoint pen ink composition.

Production of Ballpoint Pen A stainless steel chip holding a 0.4 mm diameter cemented carbide ball is filled with a ballpoint pen refill in which one end of a polypropylene pipe is fitted, and the rear end is filled with polybutene. After arranging an ink backflow preventive body consisting of 98.5 parts and 1.5 parts of fatty acid amide, the above-mentioned ballpoint pen refill was incorporated into a shaft cylinder, and a cap was attached to prepare a sample ballpoint pen.

Preparation of marking pen ink Each raw material was mixed in the blending amounts of Examples 3 to 5 and Comparative Examples 3 to 5, stirred and dissolved at 20 ° C. for 3 hours, and then filtered to obtain a marking pen ink composition.

Preparation of a marking pen An ink occlusion body in which a polyester sliver is coated with a synthetic resin film is impregnated with the marking pen ink composition, accommodated in a shaft tube made of polypropylene resin, and a polyester fiber is placed on the tip of the shaft tube through a holder. A sample marking pen was obtained by assembling a resin processed chip (bullet type) in a connected state and attaching a cap.

The following tests were carried out using the obtained ink compositions and writing instruments.
Ink stability test 5 g of each prepared ink was transferred to a sample bottle, covered, and allowed to stand at 20 ° C. for 30 days. Thereafter, the state of the ink was visually confirmed.

Writing test-Initial writing Using the sample writing instrument, the state of the handwriting when the spiral circle was continuously written by hand on black writing paper was visually confirmed.
-Writing over time After the sample writing instrument was left at 20 ° C. for 60 days with the cap facing downward, the state of the handwriting when the spiral circle was continuously written by hand on black writing paper was visually confirmed.
The results of each test are shown below.

In addition, the evaluation regarding the symbol in the said table | surface is as follows.
Ink stability test ○: No change in a uniform state.
X: A supernatant-like two-layer separation is observed.
Written test / initial writing ○: Clear handwriting is obtained.
X: The color tone is thin and it is not clear handwriting.
-Writing over time ○: A good handwriting can be formed from writing, and the resulting handwriting is also clear.
(Triangle | delta): The shading is seen in a handwriting or the density accompanying the sedimentation of a coloring component is seen in a handwriting.
X: Writing is impossible.

Claims (4)

An aqueous ink composition for a writing instrument comprising a particle surface of white inorganic particle powder coated with a paste and an organic pigment attached to the coating portion, a dispersion stabilizer, a surfactant, and water. object. The water-based ink composition for a writing instrument according to claim 1 , comprising hollow resin particles .   The water-based ink composition for a writing instrument according to claim 1 or 2, comprising a thickener. A writing instrument comprising the water-based ink composition for a writing instrument according to any one of claims 1 to 3.