JP4093932B2 - 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 a writing instrument and a writing instrument filled with the water-based ink composition for a writing instrument and an ink backflow preventive body that follows the ink consumption.

  Conventionally, as ink having shear thinning among aqueous inks, an ink composition for aqueous ballpoint pens containing a shear thinning agent such as a high molecular weight polysaccharide has been disclosed (for example, see Patent Document 1).

This type of ink has a high viscosity when it is left to stand without shear stress, and is stably held in the mechanism. When writing, the ink in the vicinity of the ball is low due to the high shear force of the ball rotating at high speed. As a result, the ink is discharged from the gap between the ball and the ball container and transferred onto the paper surface. Since the ink transferred onto the paper surface is released from the shearing force, it becomes a high viscosity state again, and does not cause the blotting of the handwriting, which is a defect of the conventional aqueous ink composition.
Furthermore, ink leakage does not occur depending on the above-described shear thinning, and a flow rate adjusting member (pen core) for adjusting the ink flow rate is not required, so that a writing instrument having a simple structure can be obtained.

  The conventional writing instrument using water-based ink exhibiting shear thinning has a simple structure, and air pressure does not enter the interior as the ink is consumed as in the writing instrument using the flow rate adjusting member. While there is little change and there is an advantage that the ink does not fall off, special consideration is required in preparing and filling the ink. This is to prevent the solvent in the ink from evaporating on the rear end surface of the ink, or to follow the ink consumption as the writing front end portion is in the upward state (upright state) to prevent the ink from flowing backward. This is because the backflow prevention body (liquid stopper) is filled, and since the ink exists in an airtight space that is blocked from the outside air, if the gas is mixed in the ink, the gas gathers over time and bubbles are generated. This is because the ink is generated and has an adverse effect on the ink discharge at the time of writing, and if there is a bubble at the tip of the writing, writing may be impossible.

  Apart from this, as a writing instrument of the type filled with the ink backflow preventive body, by providing a valve mechanism in the vicinity of the writing tip, it can be filled with an aqueous ink composition that does not exhibit shear thinning, As with, the presence of bubbles will adversely affect writing performance.

In order to solve the problems described above, defoaming treatment is mainly performed to remove the gas in the ink mechanically. However, it is difficult to perform sufficient defoaming by this method alone, and the gas remains in the ink. There is. Further, when a colorant insoluble in a solvent such as pigment, metal powder, titanium oxide or the like is used, if the treatment such as centrifugal defoaming is performed, the colorant is unevenly distributed in the ink container.
Therefore, a method of chemically removing the gas in the ink is conceivable. For example, attempts to add an ascorbic acid derivative, α-tocopherol, or catechins are disclosed (for example, patents). References 2 to 4).
Japanese Patent Laid-Open No. 4-214782 Japanese Patent Publication No.7-113101 Japanese Patent Laid-Open No. 10-330672 JP-A-10-298483

However, among the compounds that chemically remove the gas in the ink, ascorbic acid derivatives tend to cause aggregation of the pigment in a system using a pigment as a colorant, which limits practical use. Moreover, since α-tocopherol is insoluble in water, it is separated over time and it is difficult to permanently develop the gas removal function. Further, although the catechins can be removed satisfactorily without causing a problem such as a limited colorant to be applied or a gas removal function disappearing in a short period of time, catechins are natural. The extract is low in purity, and has few functional groups that exhibit reducing properties and remove gas, and a large amount is required to obtain a desired effect.
The present invention provides a water-based ink composition for a writing instrument that has wide utility and can provide good writing performance by using a specific compound that chemically removes the gas in the ink described above, and a built-in ink composition for the same. Is to provide a writing instrument.

  The present invention requires a water-based ink composition for a writing instrument comprising ferulic acid or a salt thereof in a water-based ink composition comprising at least a colorant and water. Further, it is a requirement that the ferulic acid or a salt thereof is contained in an ink composition in an amount of 0.01 to 5% by weight. Furthermore, a writing instrument formed by filling the ink composition into a writing instrument that contains an ink backflow preventer that follows as the ink is consumed is required.

  Since the ink composition of the present invention can remove bubbles by blending ferulic acid or a salt thereof, the writing instrument using the ink does not generate bubbles over time, and the ink is smoothly led out to the writing tip. It is possible to maintain stable writing performance, and good handwriting can be obtained continuously.

  The present inventor has little influence on various additives among the compounds that chemically remove the gas in the ink described above, and exhibits a sufficient gas removal function with a small amount of addition and permanently functions. As a result of intensive studies on the compound to be expressed, it has been found that ferulic acid or a salt thereof exhibits a remarkable gas removal function in the long term while maintaining good writing performance.

The ferulic acid and salts thereof can be obtained by extracting from plants containing the ferulic acid or industrially producing them by chemical synthesis, and exhibiting good oxygen absorption ability when added to the ink composition. To do. Therefore, it is presumed that the gas containing oxygen in the ink is prevented from collecting and forming bubbles. Since the ferulic acid exhibits strong reducibility in an alkaline atmosphere, it is preferable to use it after adjusting the pH of the ink composition to 7 or more.
In addition, the ferulic acid can be improved in water solubility by being in the form of a salt, and can exhibit oxygen absorption ability more effectively in the ink. The ferulic acid salt may be added to the ink after the salt has been prepared in advance, or the ferulic acid and the basic substance for salt formation may be separately added to the ink composition, It may be a salt formed with.
Examples of the salt of ferulic acid include alkali metal salts such as sodium salt and potassium salt, alkaline earth metal salts such as magnesium salt and calcium salt, and inorganic salts such as ammonium salt.

The ferulic acid or a salt thereof can be added in an amount of 0.01 to 5% by weight, preferably 0.05 to 1% by weight in the ink composition.
If it is 0.01% by weight or less, it is difficult to obtain the desired bubble generation inhibiting effect, and if it is 5% by weight or less, the desired effect can be sufficiently obtained, and no further addition is required.

As the colorant, all dyes and pigments that can be dissolved or dispersed in an aqueous medium can be used, and specific examples thereof are illustrated below.
As the dye, an acid dye, a basic dye, a direct dye, or the like can be used.
As an acid dye,
New coccin (CI. 16255),
Tartrazine (C.I. 19140),
Acid Blue Black 10B (C.I. 20470),
Guinea Green (C.I.42085),
Brilliant blue FCF (C.I.42090),
Acid Violet 6B (C.I. 42640),
Soluble Blue (C.I. 42755),
Naphthalene green (C.I. 44025),
Eosin (C.I. 45380),
Phloxin (C.I. 45410),
Erythrosine (C.I. 45430),
Nigrosine (C.I. 50420),
Acid flavin (C.I. 56205) or the like is used.

As basic dye,
Chrysoidine (C.I. 11270),
Methyl violet FN (C.I. 42535),
Crystal violet (C.I. 42555),
Malachite green (C.I. 42000),
Victoria Blue FB (C.I. 44045),
Rhodamine B (C.I. 45170),
Acridine orange NS (C.I. 46005),
Methylene blue B (C.I. 52015) or the like is used.

As a direct dye,
Congo Red (C.I. 22120),
Direct Sky Blue 5B (C.I. 24400),
Violet BB (C.I. 27905),
Direct deep black EX (CI 30235),
Caillas Black G Conch (C.I. 35225),
Direct Fast Black G (C.I. 35255),
Phthalocyanine blue (C.I. 74180) or the like is used.

Examples of the pigment include inorganic pigments such as carbon black and ultramarine, and organic pigments such as copper phthalocyanine blue and benzidine yellow, as well as water dispersion finely and stably dispersed in an aqueous medium in advance using a surfactant or resin. Pigment products and the like are used. I. Pigment Blue 15: 3B [Product name: Sandy Super Blue GLL, pigment content 24%, manufactured by Sanyo Dye Co., Ltd.]
C. I. Pigment Red 146 [Product name: Sandye Super Pink FBL, pigment content 21.5%, manufactured by Sanyo Dye Co., Ltd.]
C. I. Pigment Yellow 81 [Product name: TC Yellow FG, pigment content about 30%, manufactured by Dainichi Seika Kogyo Co., Ltd.]
C. I. Pigment Red 220/166 [Product name: TC Red FG, pigment content of about 35%, manufactured by Dainichi Seika Kogyo Co., Ltd.].
As the resin for dispersing the pigment, polyamide resin, polyurethane resin, polyester resin, epoxy resin, melamine resin, phenol resin, silicone resin, polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl acetate, polyvinyl chloride, polyvinylidene chloride, Examples thereof include polystyrene, acrylic acid resin, maleic acid resin, gum arabic, cellulose, dextran, casein, and derivatives thereof, and copolymers of the above-described resins.
As the fluorescent pigment, a fluorescent pigment in the form of fine particles of synthetic resin in which various fluorescent dyes are formed into a solid solution in a resin matrix can be used.
In addition, white pigments such as titanium dioxide, metal powders such as aluminum, natural mica, synthetic mica, alumina, 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 A functional pigment or the like can also be used.
The pigments can be used alone or in combination of two or more, and are used in the range of 1 to 25% by weight, preferably 2 to 15% by weight in the ink composition.

Furthermore, if necessary, a water-soluble organic solvent can be added to the water-based ink composition of the present invention.
As the water-soluble organic solvent, a conventional general-purpose solvent compatible with water is used. 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 mono Examples include ethyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone and the like.
In addition, the said water-soluble organic solvent can also use 1 type (s) or 2 or more types together, and is used in 2-60 weight% in an ink composition, Preferably it is 5-35 weight%.

In addition, a pH adjuster, an antiseptic, or an antifungal agent can be added as necessary.
Examples of the pH adjuster include inorganic basic salts such as ammonia, sodium carbonate, sodium phosphate, sodium hydroxide and sodium acetate, and organic basic compounds such as water-soluble amine compounds such as triethanolamine and diethanolamine.
Examples of the preservative or antifungal agent include carboxylic acid, sodium salt of 1,2-benzisothiazolin-3-one, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6 -Tetrachloro-4- (methylsulfonyl) pyridine and the like.
Furthermore, an antifoaming agent such as a fluorine-based surfactant that improves the permeability of the solvent, a nonion, an anion, a cationic surfactant, or dimethylpolysiloxane may be added.

  In addition, one 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 within the range that does not impair drying resistance, or urea In addition, one or more wetting agents such as nonionic surfactants, sorbitol, mannitol, sucrose, glucose, reduced starch hydrolyzate, sodium pyrophosphate can be added.

A shear thinning agent can be added to the ink composition.
The shear thinning of the ink composition is a rheological characteristic that has a property of being extremely high viscosity and difficult to flow in a static state or when the stress is low, and showing a good fluidity by decreasing the viscosity when the stress increases. It means liquidity also called thixotropic property or pseudoplasticity. Therefore, the ink composition is temporarily destroyed in the three-dimensional structure under high shear stress at the time of writing and the viscosity of the ink is lowered, and the ink at the tip of the writing becomes a low-viscosity ink suitable for writing and is transferred to the paper surface. The When not writing, the viscosity of the ink becomes high, and leakage of the ink can be prevented, and separation and backflow of the ink can be prevented. Also, the ink physical properties can be kept stable over time.
In particular, a ballpoint pen with a ball held at the tip of the writing has a low viscosity suitable for writing under high shear stress at the time of writing, and the gap between the ball and the ball house moves by capillary force and moves on the paper surface. It is necessary to have ink characteristics that can be transferred to, and when not writing, the viscosity of all inks, including the vicinity of the ball, must be increased to prevent ink leakage, ink separation, and backflow. The ink viscosity at 100 rpm measured by an E-type rotational viscometer is 3 to 200 mPa · s (25 ° C.), preferably 5 to 100 mPa · s, and the shear thinning index is 0.1 to 0.99, preferably 0. Ink compositions exhibiting .1 to 0.8 are preferred.

As the shear thinning agent, a water-soluble or dispersible substance is effective, and xanthan gum, welan gum, and succinoglycan whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose (average molecular weight) About 1,000 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 and carrageenan Thickening polysaccharides having gelling ability extracted from seaweed such as benzylidene sorbitol and benzylidene xylitol or derivatives thereof, crosslinkable acrylic acid polymer, inorganic fine particles, polyglycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, poly Tylene glycol fatty acid ester, polyoxyethylene castor oil, polyoxyethylene lanolin, lanolin alcohol, beeswax derivative, polyoxyethylene alkyl ether, polyoxypropylene alkyl ether, polyoxyethylene alkyl phenyl ether, fatty acid amide, etc. have an HLB value of 8 to Twelve nonionic surfactants, salts of dialkyl or dialkenylsulfosuccinic acid and the like can be exemplified, and they can be used alone or in combination.
Furthermore, a mixture of N-alkyl-2-pyrrolidone and an anionic surfactant, a mixture of polyvinyl alcohol and an acrylic resin can also be used.
The shear thinning agent can be used in the range of 0.1 to 20% by weight in the ink composition.

In addition, a rust preventive agent, a lubricant, etc. can be added as needed.
Examples of the rust inhibitor include benzotriazole and derivatives thereof, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, sodium thiosulfate, ethylenediaminetetraacetate, saponin, and dialkylthiourea.
Examples of the lubricant include metal soap, polyalkylene glycol fatty acid ester, ethylene oxide addition type cationic activator, phosphate ester activator, thiocarbamate, dimethyldithiocarbamate and the like.
A particularly preferably used lubricant is a phosphate ester surfactant described in JP-B-1-13508.

  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 structure and shape of the ballpoint pen itself are not particularly limited, and a conventional one can be applied. For example, the ballpoint pen has an ink containing tube filled with an ink composition, and the ink containing tube has a ball. An example is a ballpoint pen that communicates with a tip attached to the tip, and further has a liquid stopper for backflow prevention in close contact with the end face of the ink.

The ballpoint pen tip will be described in more detail. A tip formed by holding a ball in a ball holding portion obtained by pressing and deforming the vicinity of the tip of a metal pipe inward from the outer surface, or a metal material is cut by a drill or the like A chip formed by holding the ball in the ball holding part formed by the above, or a ball held in a chip formed by cutting a metal pipe or metal material, and the like that is urged forward by a spring body, etc. Can be applied.
The ball may be cemented carbide, stainless steel, ruby, ceramic, or the like.

As the ink containing tube for containing the ink composition, for example, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate or the like is preferably used from the viewpoint of low ink evaporation and productivity. Further, by using a transparent, colored transparent, or translucent molded body as the ink containing tube, the ink color, the remaining ink amount, and the like can be confirmed.
In addition to directly connecting the chip to the ink storage tube, the ink storage tube and the chip may be connected via a connecting member.
The ink storage tube may be a refill type in which the refill is stored in a shaft tube, or the shaft tube itself having a tip attached to a tip is used as an ink container, and ink is directly applied to the shaft tube. It may be filled.

The back end of the ink composition housed in the ink housing tube is filled with an ink backflow prevention body.
The ink backflow preventer can be either liquid or solid, and the liquid ink backflow preventive includes non-volatile media such as polybutene and silicone oil. Aluminum silicate or the like can also be added.
Moreover, a resin molding is mentioned as a solid ink backflow prevention body.
Further, the liquid and solid ink backflow preventers can be used in combination.

  The aqueous ink composition for a writing instrument of the present invention is charged with a dye or pigment (pigment dispersion), ferulic acid or a salt thereof, and if necessary, a shear thinning agent or various additives in an aqueous medium, and if necessary, heated. Then, it is prepared by stirring, dissolving and dispersing, and is used by filling in a writing instrument in the form of a ballpoint pen, a sign pen, a felt pen, a brush pen or the like.

The ink composition of the present invention and the ink composition of the comparative example are shown below.
In addition, the number in a mixing | blending shows a weight part.
Example 1
Blue pigment 25.0
[Product name: SS BLUE GLL, manufactured by Sanyo Dye Co., Ltd.]
Ethylene glycol 15.0
Succinoglycan 0.3
(Organic acid-modified heteropolysaccharide consisting of glucose and galactose)
1,2-Benzisothiazolin-3-one 0.1
[Product name: Proxel XL-2, manufactured by Zeneca Corporation]
Triethanolamine 0.5
Ferulic acid 0.3
Water 58.8
Total 100.0

  A water-based ink composition for a writing instrument is obtained by mixing the blend, stirring the mixture at room temperature with a disper for 3 hours, and filtering.

Example 2
Red dye 5.0
[Product name: Phloxine, C.I. I. Acid Red92, C.I. I. 45410]
Diethylene glycol 15.0
Xanthan gum 0.3
Sodium carbonate 0.3
Coal acid 0.3
Ferulic acid 0.1
Water 79.0
Total 100.0

  A water-based ink composition for a writing instrument is obtained by mixing the blend, stirring the mixture at room temperature with a disper for 3 hours, and filtering.

Example 3
Aluminum paste 7.0
[Product name: 96-2104, manufactured by Toyo Aluminum Co., Ltd.]
Glycerin 15.0
Succinoglycan 0.3
(Organic acid-modified heteropolysaccharide consisting of glucose and galactose)
Sodium omadin 0.3
[Product name: Topside 280, manufactured by Permachem Co., Ltd.]
EDTA amine salt 1.0
[Product name: Kirest M-50, manufactured by Kirest Co., Ltd.]
α-cyclodextrin 3.0
[Shisui Port Sugar Co., Ltd., trade name: DEXIPEARL K-100]
Triethanolamine 0.3
Ferulic acid 0.2
Water 72.9
Total 100.0

  A water-based ink composition for a writing instrument is obtained by mixing the blend, stirring the mixture at room temperature with a disper for 3 hours, and filtering.

Comparative Example 1
A water-based ink composition for writing instruments was obtained in the same manner except that the ferulic acid used in Example 1 was replaced with water.

Comparative Example 2
A water-based ink composition for writing instruments was obtained in the same manner except that the ferulic acid used in Example 2 was replaced with water.

Comparative Example 3
A water-based ink composition for a writing instrument was obtained in the same manner except that the ferulic acid used in Example 3 was replaced with water.

  Example ink and comparative example ink were prepared by the ink preparation method, and a stainless steel chip holding a ball having a diameter of 0.5 mm was filled in a ballpoint pen refill fitted to one end of a polypropylene pipe, After being in close contact with the rear end surface of the ink and filled with an ink backflow preventive body and subjected to a centrifugal treatment, the ballpoint pen refill was incorporated into a shaft tube to form a ballpoint pen.

The initial ballpoint pen obtained as described above and the ballpoint pen left after standing for 60 days at 50 ° C. (after aging) were visually observed for the presence or absence of bubbles in the ink containing tube and the handwriting test.
The results are shown below.

The criteria in the table are as follows.
State of handwriting ○: Good handwriting is obtained.
X: Scratch is seen in the handwriting.

Claims (3)

  A water-based ink composition for writing instruments, comprising ferulic acid or a salt thereof in a water-based ink composition comprising at least a colorant and water.   The water-based ink composition for a writing instrument according to claim 1, comprising 0.01 to 5% by weight of the ferulic acid or a salt thereof in the ink composition.   A writing instrument of a type containing an ink backflow preventer that follows as the ink is consumed, wherein the ink composition according to claim 1 is filled.