JP2009234093A - Water-based ballpoint pen - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based ballpoint pen having wide practicability and obtaining good writing performance by incorporating ink containing a specific compound for chemically removing gas in the ink in a ballpoint pen having a structure in which a liquid plug is filled at the rear end of the ink. <P>SOLUTION: The water-based ballpoint pen incorporates a water-based ink composition containing a colorant, water, a monomer or an oligomer of 2,5-dimercapto-1,3,4-thiadiazole, and has an ink back flow-preventing body following the consumption of the ink at the rear end of the ink with close contact. The water-based ink composition contains a thixotropy-imparting agent. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a water-based ballpoint pen. Furthermore, the present invention relates to a water-based ballpoint pen including a water-based ink composition and an ink backflow preventer that follows as the ink is consumed.

  Conventionally, among water-based inks contained in a ballpoint pen, an ink composition for water-based ballpoint pens having shear thinning viscosity by adding a shear thinning agent such as a polymer polysaccharide has been disclosed (for example, Patent Documents). 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-mentioned shear thinning and no flow rate adjusting member (pen core) for adjusting the ink flow rate is required. A ballpoint pen with a simple structure can be constructed.
In addition, it prevents the solvent in the ink from evaporating on the rear end surface of the ink of the ballpoint pen with the simple structure, and prevents backward movement and backflow of the ink when the writing tip (tip) is in the upward state (upright state). For this purpose, an ink backflow prevention body (liquid stopper) that follows as the ink is consumed is filled.

  In the ballpoint pen with the above structure, since the ink contained in the ballpoint pendant exists in an airtight space that is blocked from the outside air by the ink backflow prevention body, if the gas is mixed in the ink, the gas gathers over time and bubbles are generated. , It may adversely affect the ink output during writing. This is particularly noticeable in ink having shear thinning viscosity in which bubbles do not easily move backward, and writing may be impossible if bubbles exist at the writing tip.

  Separately, when a low-viscosity ink is incorporated in a ballpoint pen of a simple structure type that is filled with the ink backflow prevention body, when such a bubble is generated, a bubble is formed between the ink and the ink backflow prevention body. When heated in a state where there is, there is a possibility that the bubbles expand and the ink backflow preventive body collapses or ink is ejected, and this phenomenon may adversely affect the 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. In addition, when using a colorant that is insoluble in a solvent such as pigment, metal powder, titanium oxide, etc., if the specific gravity difference from the vehicle is large, the colorant will be contained in the ink container when processing such as centrifugal defoaming is performed. The problem of uneven distribution occurs.
Therefore, a method of chemically removing the gas in the ink is conceivable. For example, attempts to add an ascorbic acid derivative or α-tocopherol have been disclosed (see, for example, Patent Documents 2 to 3).
Japanese Patent Laid-Open No. 4-214782 Japanese Patent Publication No.7-113101 Japanese Patent Laid-Open No. 10-330672

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. In addition, α-tocopherol is insoluble in water, so that it is separated over time and it is difficult to permanently develop a gas removal function.
The present invention incorporates an ink using a specific compound that chemically removes the gas in the ink into a ballpoint pen configured to fill a liquid stopper at the rear end of the ink, thereby providing good writing performance for a long time. The present invention provides an aqueous ballpoint pen that can be obtained.

The water-based ballpoint pen of the present invention incorporates a water-based ink composition containing a colorant, water, and a monomer or oligomer of 2,5-dimercapto-1,3,4-thiadiazole and follows as the ink is consumed. It is a requirement that the ink backflow prevention body is closely arranged at the rear end of the ink.
Further, the ink composition contains 0.01 to 5% by weight of the monomer or oligomer of 2,5-dimercapto-1,3,4-thiadiazole, and the water-based ballpoint pen has an atmosphere of 50 ° C. and a relative humidity of 20%. The ink weight Y after being left for 60 days and the ink weight X before being left satisfying Y / X ≦ 0.960, and the dissolved oxygen content at 20 ° C. of the water-based ink composition is 0.1 to 10 mg. / L is a requirement.
Furthermore, the water-based ink composition contains a shear thinning agent, the ink viscosity of the water-based ink composition at 20 ° C. at EM type rotational viscometer 100 rpm is in the range of 25 to 160 mPa · s, and It is a requirement that the shear thinning index is in the range of 0.1 to 0.7, and that the shear thinning agent is either succinoglycan or carrageenan.

  According to the present invention, even in a ballpoint pen configured to fill a liquid stopper at the rear end of the ink, bubbles are not generated in the ink over time, and the ink is smoothly led out to the leading end of the writing. It can be sustained and good handwriting can be obtained continuously. In particular, in ink having shear thinning viscosity, writing defects caused by the presence of bubbles near the writing tip can be more effectively suppressed.

  The present invention contains a water-based ink containing a monomer or oligomer of 2,5-dimercapto-1,3,4-thiadiazole in a ballpoint pen configured to be filled with an ink backflow prevention body in contact with the rear end of the ink. It is a water-based ballpoint pen that chemically removes the gas in the ink to suppress the generation of bubbles and enables good writing over the long term.

Conventionally, a general-purpose mechanism is effective for the structure of the ballpoint pen tip serving as the writing tip of the ballpoint pen. For example, the ball is held in a ball holding portion in which the vicinity of the tip of a metal pipe is pressed and deformed inward from the outer surface. A chip formed by holding a ball in a ball holding part formed by cutting a metal material by a drill or the like, or a chip formed by cutting a metal pipe or metal material A ball or the like that is held forward by a spring body can be applied.
The balls may be made of cemented carbide, stainless steel, ruby, ceramic, resin or the like, and those having a diameter in the range of 0.10 mm to 2.0 mm are used.

The ink storage tube in which the writing tip is connected directly or via a connecting member is a form capable of directly storing a water-based ink composition, for example, thermoplastic such as polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, etc. A molded body made of resin is preferably used in terms of low ink evaporation and productivity, but a metal processed body can also be used. Further, the resin ink containing tube can be used to confirm the ink color, the remaining ink amount, and the like by using a transparent, colored transparent, or translucent molded body.
In addition to using the ink storage tube itself as a gripping exterior (shaft tube), the refill may be housed in a shaft tube made of a separate member as a form of a ballpoint pen refill.

The ballpoint pen using the ink storage tube can be applied in any of a cap type and a retractable type. As a retractable ballpoint pen, the writing tip provided on the ballpoint pen refill is housed in the shaft cylinder in a state exposed to the outside air, and the writing tip is projected from the opening of the shaft tube by the operation of the retracting mechanism. Anything can be used.
Examples of the operation method of the retracting mechanism include a knock type, a rotary type, and a slide type.
The knock type has a knock portion on the rear end portion of the shaft tube and the side surface of the shaft tube, and by pressing the knock portion, the writing tip portion of the ballpoint pen refill is projected and retracted from the front end opening portion of the shaft tube, or on the shaft tube. The structure which makes the writing tip part of a ball-point pen refill appear and disappear from the axial cylinder front-end opening part by pressing the provided clip part can be illustrated.
The rotary type has a rotating part at the rear part of the shaft cylinder, and can be exemplified by a configuration in which the writing tip part of the ballpoint pen refill is projected and retracted from the front end part of the shaft cylinder by turning the rotating part.
The slide type has a slide part on the side surface of the shaft cylinder, and the sliding tip of the writing point of the ballpoint pen refill is projected and retracted from the front end opening of the shaft cylinder by operating the slide, or the clip part provided on the shaft cylinder is slid. By doing so, it is possible to exemplify a configuration in which the writing tip of the ballpoint pen refill is projected and retracted from the opening at the front end of the shaft cylinder.
The retractable ballpoint pen may be a composite-type retractable ballpoint pen in which a plurality of ballpoint pen refills are accommodated in an outer shaft.

The water-based ink composition incorporated in the ballpoint pen has a monomer or oligomer of 2,5-dimercapto-1,3,4-thiadiazole added thereto, and exhibits good oxygen absorption capacity in the ink. It is presumed that the gas containing oxygen in the inside is suppressed from forming bubbles.
The 2,5-dimercapto-1,3,4-thiadiazole monomer or oligomer may be added in an amount of 0.01 to 5% by weight, preferably 0.1 to 3% 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 even if it exceeds 5% by weight, no further bubble inhibiting effect can be obtained. I don't need it.
In addition, as an oligomer of 2,5-dimercapto-1,3,4-thiadiazole, a dimer to 10-mer oligomer is used.

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: Sandye 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.
Furthermore, a microcapsule pigment encapsulating a reversible thermochromic composition, or a thermochromic pigment such as a microcapsule pigment encapsulating a dye or pigment together with the reversible thermochromic composition can also be used.
The colorant can be used singly or in combination of two or more, and is used in the range of 1 to 25% by weight, preferably 2 to 15% by weight in the ink composition.

In addition, a water-soluble organic solvent can be added to the ink as needed, and a conventional general-purpose one that is compatible with water is used.
Examples of the water-soluble organic solvent include 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, N-methyl 2-pyrrolidone, and the like.
In addition, the said water-soluble organic solvent can also use 1 type, or 2 or more types together, It is 2-60 weight% in an ink composition, Preferably it is used in 5-35 weight%.

Furthermore, a lubricant can be added to give an effect of preventing wear of the ball seat.
Examples of the lubricant include higher fatty acids such as oleic acid, nonionic surfactants having a long chain alkyl group, polyether-modified silicone oil, thiophosphite tri (alkoxycarbonylmethyl ester) and thiophosphite tri (alkoxycarbonylethyl). Esters), phosphoric acid monoesters of polyoxyethylene alkyl ethers or polyoxyethylene alkyl aryl ethers, phosphoric acid diesters of polyoxyethylene alkyl ethers or polyoxyethylene alkyl aryl ethers, or metals thereof Examples include salts, ammonium salts, amine salts, alkanolamine salts, and the like.

In addition, by adding a shear thinning agent to the ink, ink leakage from the gap between the ball and the tip can be prevented when the ballpoint pen that fills the ink is not used, or the writing tip is directed upward (upright state) ), It is possible to prevent backflow of ink and to prevent aggregation and sedimentation of the pigment.
The viscosity of the ink composition to which the shear thinning agent is added shows an ink viscosity of 25 to 160 mPa · s at 100 ° C. at an EM rotational viscometer at 20 ° C., and a shear thinning index of 0.1. It is preferable to show ~ 0.7.
The shear thinning index (n) is expressed by an empirical formula T = Kj ⁿ (K is a non-Newtonian viscosity coefficient) obtained from rheological measurement by a viscometer such as a shear stress value (T) and a shear rate value (j). It is a value calculated by fitting.
Examples of the shear thinning agent include xanthan gum, welan gum, succinoglycan (average molecular weight of about 1 to 8 million) whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose, alka gum, guar gum, locust bean gum and A gel having a gelling ability extracted from seaweeds such as glucomannan, agar and carrageenan, polymers having a molecular weight of 100,000 to 150,000 mainly composed of derivatives thereof, hydroxyethyl cellulose, alginic acid alkyl esters, and alkyl esters of methacrylic acid. Viscous polysaccharides (such as carrageenan), benzylidene sorbitol and benzylidene xylitol or their derivatives, crosslinkable acrylic acid polymer, inorganic fine particles, polyglycerin fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyethylene glycol Nonionic surfactants having an HLB value of 8 to 12, such as Cole fatty acid ester, polyoxyethylene alkyl ether, polyoxypropylene alkyl ether, polyoxyethylene alkyl phenyl ether, fatty acid amide, salts of dialkyl or dialkenylsulfosuccinic acid, N Examples thereof include a mixture of alkyl-2-pyrrolidone and an anionic surfactant, and a mixture of polyvinyl alcohol and an acrylic resin.
In particular, succinoglycan and carrageenan are effective because a desired condition is expressed with a small amount of addition.

In addition, a pH adjuster, an antiseptic, or an antifungal agent can be added as necessary.
Examples of the pH adjuster include inorganic salts such as ammonia, sodium carbonate, sodium phosphate, sodium hydroxide and sodium acetate, organic basic compounds such as water-soluble amine compounds such as triethanolamine and diethanolamine, lactic acid and citric acid. Etc.
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 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 sorbitol, mannitol, sucrose, glucose, reduced starch hydrolyzate and sodium pyrophosphate can be added.

The water-based ink composition preferably has a dissolved oxygen content at 20 ° C. in the range of 0.1 to 10 mg / L.
By setting the amount within the above range, it is difficult for gas to be generated even when water is evaporated in a state of being contained in the ink containing tube. Therefore, depending on the monomer or oligomer of 2,5-dimercapto-1,3,4-thiadiazole The chemical gas removal effect becomes more advantageous, and the generation of bubbles can be more effectively suppressed.

The back end of the ink composition housed in the ink housing tube is filled with an ink backflow prevention body.
The ink backflow preventive composition is composed of a non-volatile liquid or a hardly volatile liquid, specifically, petroleum jelly, spindle oil, castor oil, olive oil, refined mineral oil, liquid paraffin, polybutene, α-olefin, α-olefin. Oligomers or co-oligomers, dimethyl silicone oil, methylphenyl silicone oil, amino-modified silicone oil, polyether-modified silicone oil, fatty acid-modified silicone oil, and the like, and one or more of them can be used in combination.

It is preferable to add a gelling agent to the nonvolatile liquid and / or the hardly volatile liquid to increase the viscosity to a suitable viscosity. The surface of the silica is hydrophobized, the surface is methylated fine particle silica, and aluminum silicate. , Swellable mica, hydrophobic thickeners such as bentonite and montmorillonite, fatty acid metal soaps such as magnesium stearate, calcium stearate, aluminum stearate, zinc stearate, tribenzylidene sorbitol, fatty acid amide, amide modified Examples include dextrin compounds such as polyethylene wax, hydrogenated castor oil, fatty acid dextrin, and cellulose compounds.
Furthermore, the liquid ink backflow prevention body composition and a solid ink backflow prevention body composition can be used in combination.

  The water-based ballpoint pen containing the water-based ink composition and the ink backflow preventer has an ink weight Y after being left for 60 days in an atmosphere of 50 ° C. and a relative humidity of 20%, and an ink weight X before being left is Y / X ≦ 0.960, that is, when the amount of water evaporation in the ink is 4.0% or more of the total weight before standing, the ink composition has a composition that easily evaporates the solvent. The accompanying gas generation is likely to occur. Therefore, the chemical gas removal effect by the monomer or oligomer of 2,5-dimercapto-1,3,4-thiadiazole of the present application becomes more advantageous, and the generation of bubbles can be more effectively suppressed.

Examples will be described below, but the present invention is not limited to these examples.
Table 1 shows compositions of water-based inks for ballpoint pens of Examples and Comparative Examples. The numerical values of the composition in the table indicate parts by weight.
Each ink viscosity is a value measured at 20 ° C. using an EM type rotational viscometer (manufactured by Tokyo Keiki Co., Ltd., using an EM adapter) at 100 rpm, and the shear thinning index (n) is the viscosity. It is a value calculated from the value. The amount of dissolved oxygen is a value measured at 20 ° C. using a dissolved oxygen meter (manufactured by Iijima Electronics Co., Ltd.).

The contents of the raw materials in the table will be described along the note numbers.
(1) Sanyo Dye Co., Ltd., trade name: Sundai Super Color Blue GLL
(2) Eisen Hodogaya Co., Ltd., trade name: Phloxine (3) Orient Chemical Industry Co., Ltd., trade name: Water Black 100L, C.I. I. Direct Black 19, dye content 20%
(4) 2,5-Dimercapto-1,3,4-thiadiazole (5) Dimer of 2,5-dimercapto-1,3,4-thiadiazole (6) Phosphate ester surfactant, Daiichi Kogyo Product name: Prisurf AL, manufactured by Pharmaceutical Co., Ltd.
(7) Arch Chemicals Japan, trade name: Proxel XL-2

Preparation of ink Each raw material was mixed by the compounding quantity of the said Example and a comparative example, and the water-based ink composition was obtained by stirring and dissolving at 20 degreeC for 3 hours.

Preparation of Ink Backflow Preventing Body After adding 1.5 parts of fatty acid amide as a thickener to 98.5 parts of polybutene as a base oil, an ink backflow preventing body was obtained by kneading with 3 rolls.

Production of ballpoint pen Inside a ballpoint pen refill with a stainless steel tip holding a 0.4 mm diameter cemented carbide ball fitted to one end of a polypropylene pipe (outer diameter 5.4 mm, inner diameter 3.8 mm, total length 100 mm) In addition, 1.0 g of each ink composition was filled in, and 0.1 g of the ink backflow preventer was disposed at the rear end thereof, and then the ballpoint pen refill was incorporated into a shaft tube to prepare a sample ballpoint pen.

Test A
After leaving the sample ball-point pen at 50 ° C. for 60 days, the presence or absence of bubbles in the ink containing tube and the state of the handwriting by a writing test (written on JIS P3201 writing paper A) were visually observed.
Test B
The ink weight Y after the sample ballpoint pen was left in an atmosphere of 50 ° C. and 20% relative humidity for 60 days was measured, and how much the ink weight X was decreased before the measurement was determined to determine the Y / X value. Asked.
The results are shown below.

The criteria in the table are as follows.
Written test ○: Good handwriting is obtained.
X: Scratch and line skipping are seen in the handwriting.

Claims (7)

  A water-based ink composition containing a colorant, water, and a monomer or oligomer of 2,5-dimercapto-1,3,4-thiadiazole is incorporated, and an ink backflow preventer that follows as the ink is consumed A water-based ballpoint pen placed close to the edge.   The water-based ballpoint pen according to claim 1, comprising 0.01 to 5% by weight of the 2,5-dimercapto-1,3,4-thiadiazole monomer or oligomer in the ink composition.   3. The ink weight Y after the water-based ballpoint pen is left in an atmosphere of 50 ° C. and a relative humidity of 20% for 60 days and the ink weight X before being left satisfy Y / X ≦ 0.960. Water-based ballpoint pen.   The water-based ballpoint pen according to any one of claims 1 to 3, wherein the amount of dissolved oxygen at 20 ° C of the water-based ink composition is 0.1 to 10 mg / L.   The water-based ballpoint pen according to any one of claims 1 to 4, wherein the water-based ink composition contains a shear thinning agent.   The ink viscosity at 100 rpm of an EM type viscometer at 20 ° C of the water-based ink composition is in the range of 25 to 160 mPa · s, and the shear thinning index is in the range of 0.1 to 0.7. 5. The water-based ballpoint pen according to 5.   The aqueous ballpoint pen according to claim 5 or 6, wherein the shear thinning agent is either succinoglycan or carrageenan.