JP2008274048A - Aqueous ink composition for ballpoint pen and ballpoint pen containing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aqueous ink composition for a ballpoint pen capable of maintaining stable ink discharging properties after a long time lapse, and sustaining excellent writing feeling for a long time without generating writing scratches and writing line jumps, and a ballpoint pen containing the same. <P>SOLUTION: The aqueous ink composition for the ballpoint pen includes at least a dye, water, a fluorochemical surfactant, and an alpha olefin sulfonic acid or its salt represented by the general formula, C<SB>n</SB>H<SB>2n</SB>O<SB>3</SB>SM (1). Also provided is the ballpoint pen containing the same. In C<SB>n</SB>H<SB>2n</SB>O<SB>3</SB>SM (1), n denotes an integer of 8-30, and M denotes any one of hydrogen, an alkali metal, ammonium, or an alkanolamine. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a water-based ink composition for ballpoint pens. Furthermore, the present invention relates to a water-based ink composition for ballpoint pens capable of obtaining a stable handwriting for a long period of time and a ballpoint pen incorporating the same.

A water-based ballpoint pen containing a water-based ink is widely used. In the water-based ballpoint pen, a method of adding a fluorinated surfactant to reduce the surface tension of the ink is disclosed (Patent Documents 1 and 2). reference).
By lowering the surface tension of the ink, the rotation of the ball during writing becomes smooth and the followability of the ink is improved, so that there is no blurring or line skipping in the handwriting, giving a good writing feeling It is.
Japanese Patent No. 3778918 JP-A-60-90276

However, since the fluorosurfactant has low dissolution stability in an aqueous medium, precipitation and aggregation may occur over a long period of time. As a result, clogging occurs at the tip of the writing and the ink ejection performance is deteriorated, so that there is a risk that the handwriting will be dull or skipped.
In particular, in the case where the ball diameter at the writing tip is small, since the ink discharge portion is small, the above-mentioned problems become prominent and there is a possibility that writing failure may occur.
By suppressing sedimentation and aggregation of the fluorosurfactant, the present invention can maintain stable ink ejection even after a long period of time, and can continue a good writing feeling without causing blurring or line skipping in the handwriting. A water-based ink composition for ballpoint pens and a ballpoint pen incorporating the same are provided.

The aqueous ink composition for ballpoint pens of the present invention comprises at least a dye, water, a fluorosurfactant, and an alpha olefin sulfonic acid represented by the general formulas (1) and / or (2) or a salt thereof. It is a requirement.
C _n H _2n O ₃ SM (1)
C _n H _{2n + 1} O ₄ SM (2)
(In the formula, n represents an integer of 8 to 30, and M represents hydrogen, alkali metal, ammonium, or alkanolamine.)
Furthermore, the fluorosurfactant and the alpha olefin sulfonic acid or a salt thereof are added at a ratio of 1: 2 to 1: 5, and the conductivity at 25 ° C. of the ink composition is 30 mS / cm or more. It is a requirement.
Furthermore, it is a requirement that the ballpoint pen contains the aqueous ink composition for ballpoint pens, and that the ballpoint pen is provided with a ball having a diameter of 0.5 mm or less at the writing tip.

  According to the present invention, it is possible to provide a water-based ink composition for a ballpoint pen that can maintain a stable ink ejection property even after a long period of time and can continue a good writing feeling without causing blurring or line skipping in the handwriting, and a ballpoint pen incorporating the same. . In particular, it is possible to provide a ballpoint pen that exhibits effective ink ejection stability in a ballpoint pen having a narrow ink ejection portion and a small ball diameter.

  The present invention provides a fluorosurfactant by adding an alpha olefin sulfonic acid represented by the general formula (1) or the general formula (2) or a salt thereof together with a fluorosurfactant to a water-based ink composition for ballpoint pens. The dissolution stability of the agent is improved, and stable ink ejection properties and good writing feeling are continuously expressed.

Examples of the fluorine-based surfactant include polyoxyethylene perfluoroalkyl ester, fluorine alkyl ester, fluoroalkyl (C ₂ -C ₁₀ ) carboxylic acid, N-perfluorooctanesulfonyl glutamate disodium, 3- [fluoroalkyl (C ₈ -C ₁₁ ) oxy] -1-alkyl (C ₃ -C ₄ ) sodium sulfonate, fluoroalkyl (C ₁₁ -C ₂₀ ) carboxylic acid, perfluoroalkyl (C ₇ -C ₁₃ ) carboxylic acid, monoperfluoro alkyl (C ₈ ~C ₁₆₎ ethyl phosphoric acid ester, perfluoroalkyl amine oxide, perfluoroalkyl ethylene oxide adducts and the like.

The fluorosurfactant can be added in an amount of 0.01 to 10.0% by weight, preferably 0.05 to 5.0% by weight in the ink composition.
If it is less than 0.01% by weight, it is not sufficient to reduce the surface tension of the ink, and even if it is added in excess of 10.0% by weight, the surface tension does not decrease more than a certain level. Is not required.

The alpha olefin sulfonic acid or salt thereof given by the general formulas (1) and (2) can be added to the ink in one or more kinds, thereby continuing the dissolution stability of the fluorosurfactant in the aqueous medium. Can be maintained.
Examples of the alpha olefin sulfonic acid include 1-tetradecene sulfonic acid, hexadecene sulfonic acid, 3-hydroxyhexadecyl-1-sulfonic acid, octadecene-1-sulfonic acid, and 3-hydroxy-1-octadecane sulfonic acid. Examples of the alpha olefin sulfonate include sodium, potassium and ammonium salts of the sulfonic acid (specifically, sodium 1-tetradecenesulfonate, sodium hexadecenesulfonate, 3-hydroxyhexadecyl-1-sulfone). Acid sodium, octadecene-1-sulfonic acid sodium salt, 3-hydroxy-1-octadecanesulfonic acid sodium salt).

The alpha olefin sulfonic acid or a salt thereof may be added in an amount of 0.02 to 20.0% by weight, preferably 0.1 to 10.0% by weight, in the ink composition.
If the amount is less than 0.02% by weight, it is difficult to obtain the desired effect, and even if the amount exceeds 20.0% by weight, no improvement in the dissolution stability of the fluorosurfactant is observed. No further addition is required.
The alpha olefin sulfonic acid or a salt thereof is 2 to 5 times the addition amount of the fluorosurfactant (that is, the fluorosurfactant: alpha olefin sulfonic acid or a salt thereof is 1: 2 to 1: 5. It is preferable to be added at a ratio of
By the said ratio, the solubility of a fluorine-type surfactant is expressed more effectively. If it is less than 1: 2, it is difficult to obtain the desired effect, and if it is more than 1: 5, no improvement in dissolution stability is observed, so no further addition is required.

As the dye, any dye that can be dissolved or dispersed in an aqueous medium can be used, and an acid dye, a basic dye, a direct dye, and the like can be used.
Examples of the acid dye include New Coxin (CI. 16255), Tartrazine (CI. 19140), Acid Blue Black 10B (CI. 20470), Guinea Green (CI. 42085), Brilliant Blue FCF. (CI.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) and the like are used.

  Examples of basic dyes include chrysoidine (C.I. 11270), methyl violet FN (C.I. 42535), crystal violet (C.I. 42555), malachite green (C.I. 42000), Victoria blue FB ( CI 44045), rhodamine B (C.I. 45170), acridine orange NS (C.I. 46005), methylene blue B (C.I. 52015) and the like are used.

  As direct dyes, Congo Red (C.I. 22120), Direct Sky Blue 5B (C.I. 24400), Violet BB (C.I. 27905), Direct Deep Black EX (C.I. 30235), Kaya Las Black G Conch (C.I. 35225), Direct Fast Black G (C.I. 35255), Phthalocyanine Blue (C.I. 74180) and the like are used.

  The dyes can be used singly or in combination of two or more, and are used in the range of 0.1 to 25% by weight, preferably 0.1 to 15% by weight in the ink composition.

  Furthermore, inorganic pigments such as carbon black and ultramarine, organic pigments such as copper phthalocyanine blue and benzidine yellow, water-dispersed pigment products that have been finely and stably dispersed in an aqueous medium in advance using a surfactant, and various fluorescent properties Synthetic resin fine-particle fluorescent pigment, pearl pigment, gold and silver metallic pigment, phosphorescent pigment, white pigment such as titanium dioxide, metal powder such as aluminum, fragrance or fragrance capsule pigment Etc. can also be used together.

A water-soluble organic solvent may be added to the ink. 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%.

  Furthermore, a water-soluble resin can be added in order to impart adhesion and viscosity to the paper surface. Examples of the water-soluble resin include alkyd resins, acrylic resins, styrene maleic acid copolymers, cellulose derivatives, polyvinyl pyrrolidone, polyvinyl alcohol, and dextrin. The water-soluble resin can be used alone or in combination of two or more, and is used in the range of 1 to 30% by weight in the ink composition.

  In addition, pH adjusters such as inorganic salts such as sodium carbonate, sodium phosphate and sodium acetate, organic basic compounds such as water-soluble amine compounds, metal soap, polyalkylene glycol, phosphate ester, ethylene as necessary Lubricants such as oxide addition type cationic activators and phosphoric acid activators, rust preventives such as benzotriazole, tolyltriazole, dicyclohexylammonium nitrite, diisopropylammonium nitrite, saponin, carboxylic acid, 1,2-benzthiazoline 3-one Sodium salt, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6-tetrachloro-4- (methylsulfonyl) pyridine and other preservatives or antifungal agents, urea, Nonionic surfactant, Sorbit , Mannitol, sucrose, glucose, reduced starch hydrolyzate, wetting agents such as sodium pyrophosphate, it may also be used defoamers, silicone-based surfactants to improve the ink permeability.

A shear thinning agent can also be added to the ink composition.
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 Carbohydrates having gelling ability extracted from seaweed such as benzylidene sorbitol and benzylidene xylitol or their derivatives, crosslinkable acrylic acid polymers, inorganic fine particles, nonionic surfactants having an HLB value of 8 to 12, and dialkylsulfosuccinic acid Metal salts and nets Can be exemplified a salt, further, be added in combination in the ink composition N- alkyl-2-pyrrolidone and anionic surfactant can have stable shear thinning.

In addition, in the ink composition comprised from the said each component, when the electrical conductivity in 25 degreeC is 30 mS / cm or more, since the electrolyte concentration in ink exceeds 1.8 weight%, melt | dissolution of fluorosurfactant It becomes easy to produce precipitation and agglomeration. Therefore, the addition of the alpha olefin sulfonic acid or a salt thereof becomes more useful. The alpha olefin sulfonic acid or a salt thereof is a useful additive for the ink having the conductivity because it can suppress the precipitation of the fluorosurfactant without changing the conductivity of the ink composition. In addition, as an electrical conductivity of the ink composition applied by this application, 500 mS / cm or less is suitable.
The electrolyte generally represents a substance that ionizes into a cation and an anion when dissolved in an aqueous medium. The electrolyte ions include sodium ion, potassium ion, calcium ion, magnesium ion, chloride ion, and phosphate ion. And bicarbonate ions. When the electrolyte is present in a large amount in the ink, the solubility of the fluorosurfactant in an aqueous medium tends to decrease.
Since the conductivity shows a specific relationship (Colelausch's square root rule) with the molar concentration of the electrolyte, it becomes clear that the conductivity range is involved in the precipitation of the fluorosurfactant.

Furthermore, when the ink composition is filled in the ink container such as the shaft cylinder, an ink backflow prevention body (liquid stopper) can be disposed at the rear end of the ink composition.
As the ink backflow preventer, either liquid or solid can be used, and examples of the liquid ink backflow preventer include non-volatile media such as polybutene, α-olefin oligomer, silicone oil, and refined mineral oil. If desired, silica, aluminum silicate, swellable mica, fatty acid amide and the like can be added to the medium. Moreover, a resin molding is mentioned as a solid ink backflow prevention body. The liquid and solid ink backflow preventers can be used in combination.

The structure of the writing tip portion (tip) of the ballpoint pen filled with the ink composition is effective in a conventional general-purpose mechanism, and the ball holding portion is formed by pressing and deforming the vicinity of the tip of a metal pipe inward from the outer surface. A chip that holds the ball, or a chip that holds the ball in the ball holding part formed by cutting a metal material with a drill or the like, or a metal pipe or metal material that is cut It is possible to apply a ball that is held by the chip and biased forward by a spring body.
The balls may be made of cemented carbide, stainless steel, ruby, ceramic, resin, etc., and those having a diameter in the range of 0.10 mm to 2.0 mm, preferably 0.15 mm to 0 in diameter. A relatively small one of 5 mm is used.

  As the shaft cylinder containing the ink composition, either metal or resin can be used, but a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, etc. has low ink evaporation and productivity. In terms of surface. Further, by using a transparent, colored transparent, or translucent material as the molded body, it is possible to confirm the ink color, the remaining amount of ink, and the like. In that case, discoloration of the ink in the shaft cylinder when not in use can be suppressed by providing an ultraviolet absorbing layer on the outer surface of the shaft cylinder or forming the shaft cylinder with a material to which an ultraviolet absorber is added.

In addition to directly connecting the tip to the shaft tube, the shaft tube and the chip may be connected via a connecting member.
In the case where the ink composition accommodated in the shaft cylinder has a low viscosity, a method of mounting an ink holding member on the front of the shaft cylinder and storing the ink composition directly in the shaft cylinder, A method of impregnating the ink composition into a fiber processed body and storing it is mentioned.
The shaft cylinder has a shaft cylinder itself with a tip attached to the tip as an ink container, and in addition to a structure in which ink is directly filled into the shaft cylinder, the refill is also a shaft cylinder ( The structure may be accommodated in the exterior.

Examples will be described below, but the present invention is not limited to these examples.
The composition of the water-based ink for ballpoint pens of Examples and Comparative Examples is shown in the following table. In addition, the numerical value of a composition in a table | surface shows a weight part.

The contents of the raw materials in the table will be described along the note numbers.
(1) Product name: Acid Blue PG (CI Acid blue 90), manufactured by Sumitomo Chemical Co., Ltd.
(2) Product name: Phloxin (CI Acid red 92) manufactured by Eisen Hodogaya Co., Ltd.
(3) Product name: Special Yellow NS (CI Acid yellow 9), manufactured by LANXESS
(4) Seimi Chemical Co., Ltd., trade name: Surflon S-131 (30% active ingredient)
(5) Product name: OS-14, manufactured by Nikko Chemicals Co., Ltd.
(6) Product name: Liporan PB-800, manufactured by Lion Corporation
(7) Sanki Co., Ltd., trade name: Kelzan (8) Phosphate ester surfactant, Daiichi Kogyo Seiyaku Co., Ltd., trade name: Prisurf AL

Preparation of Ink Components other than the shear thinning agent were added to water, mixed and stirred, and then the shear thinning agent was added, and the mixture was prepared by stirring at 25 ° C. with a disper at 400 rpm for 1 hour.
In addition, about each ink, the electrical conductivity in 25 degreeC was measured using the conductivity meter (The Yokogawa Electric Corporation make, SC82).

Preparation of Ink Backflow Preventer Body In 85 parts of polybutene as a base oil, 15 parts of fatty acid amide as a thickener was added, and then kneaded with three rolls to obtain an ink backflow preventer body.

Preparation of Ballpoint Pen 1 g of each ink composition is filled in a ballpoint pen refill in which a stainless steel tip holding a ball of a cemented carbide having a diameter of 0.3 mm is fitted to one end of a polypropylene pipe, and the rear end thereof is filled. After the ink backflow preventer was disposed, the ballpoint pen refill was incorporated into a shaft tube to prepare a sample ballpoint pen.

The following tests were conducted using the ink and the sample ballpoint pen.
Precipitation test 20 g of the prepared ink was put in a plastic container, sealed, and left at 50 ° C. for 30 days. Thereafter, the temperature was lowered to 25 ° C., and the ink at the bottom of the plastic container was observed with an optical microscope.
Written test After the sample ballpoint pen, which was confirmed to be writable, was left at 50 ° C for 30 days with the pen tip facing down, the state of the handwriting when the hand-written spiral circle was continuously written on JIS P3201 writing paper A It was observed visually.
The results of the test are shown in the following table.

The evaluation of the test results is as follows.
Precipitation test ○: No precipitate.
X: Precipitates are confirmed.
Written test ○: Good handwriting can be obtained without blurring or line skipping.
Δ: Slight blurring or line skipping occurs.
X: Scratch or line skip occurs or writing becomes impossible.

Claims (5)

A water-based ink composition for ballpoint pens comprising at least a dye, water, a fluorosurfactant, and an alpha olefin sulfonic acid represented by the general formula (1) and / or (2) or a salt thereof.
C _n H _2n O ₃ SM (1)
C _n H _{2n + 1} O ₄ SM (2)
(In the formula, n represents an integer of 8 to 30, and M represents hydrogen, alkali metal, ammonium, or alkanolamine.)   The aqueous ink composition for ballpoint pens according to claim 1, wherein the fluorosurfactant and the alpha olefin sulfonic acid or a salt thereof are added in a ratio of 1: 2 to 1: 5.   The water-based ink composition for ballpoint pens according to claim 1 or 2 whose electric conductivity in 25 ° C of said ink composition is 30mS / cm or more.   The ball-point pen which incorporated the water-based ink composition for ball-point pens in any one of the said Claims 1 thru | or 3.   The ball-point pen according to claim 4, wherein the ball-point pen is provided with a ball having a diameter of 0.5 mm or less at a writing tip.