JP2015120777A - Aqueous ink composition for ballpoint pen and ballpoint pen containing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous ink composition for a ballpoint pen that satisfies dry-up resistance and exhibits a stable writing performance over a long period of time even if it is an aqueous ink using a shear-viscosity reducing agent, which is applicable for a writing instrument of a simple structure and to provide a ballpoint pen that contains the aqueous ink composition.SOLUTION: The aqueous ink composition for a ballpoint pen contains a coloring agent, water, a shear-viscosity reducing agent, and a copolymer of formulae (1), (2) and (3) as given below. The ballpoint pen contains the aqueous ink composition for a ballpoint pen. [In the formulae, l, m, and n satisfy both m/m+n≥0.8 and l/l+m+n≥0.1; and x is x≥1.]

Description

  The present invention relates to a water-based ink composition for ballpoint pens. Furthermore, it is related with the water-based ink composition for ball-point pens which is excellent in the dry-up-proof performance in a nib and has shear thinning viscosity.

Conventionally, an aqueous ballpoint pen ink composition containing a shear thinning agent such as xanthan gum or diutan gum has been disclosed (for example, see Patent Documents 1 and 2).
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 highly viscous state and does not cause handwriting blur, which is a defect of the conventional water-based ink composition. In addition, ink leakage does not occur due to the above-mentioned shear thinning and there is no need for a flow rate adjusting member (temporary ink retaining member such as a comb-like member) for adjusting the ink flow rate. It has been widely applied because it has many advantages such as obtaining writing instruments.
However, in the water-based ink, since the shear thinning agent may impair the dry-up resistance, leaving the pen tip exposed to the air for a long time may cause handwriting blurring or writing at the beginning of the handwriting. Problems such as disappearance may occur.

Then, the proposal which adds water-soluble organic solvents, such as glycerin, urea, and its derivative (s) as a wetting agent, and improves dry-up-proof performance is made | formed (for example, refer patent document 3).
However, inks containing the above-mentioned wetting agents are often insufficient in the drying prevention effect or increase the viscosity of the ink, which tends to cause poor writing such as line skipping and blurring. For example, in the addition of urea, When water is evaporated from the nib and the concentration of the water-soluble organic solvent is increased, a solid content is deposited on the nib, which causes a so-called flower bloom phenomenon, which deteriorates the appearance and may cause blurring.

JP 59-74175 JP 2005-68363 A JP-A-8-127746

  The present invention is a water-based ink composition for ballpoint pens that satisfies dry-up resistance and can exhibit stable writing performance for a long period of time even if it is a water-based ink using a shear thinning agent that can be applied to a writing instrument having a simple structure. An object and a ballpoint pen incorporating the object are provided.

〔式中のｌ，ｍ，ｎはｍ／ｍ＋ｎ≧０．８を満たすとともに、ｌ／ｌ＋ｍ＋ｎ≧０．１を満たす。また、ｘはｘ≧１である。〕
更に、前記着色剤が可逆熱変色性組成物を内包したマイクロカプセル顔料であることを要件とする。
更には、前記いずれかのボールペン用水性インキ組成物を内蔵したボールペンを要件とする。 The water-based ink composition for a ballpoint pen of the present invention is required to contain a colorant, water, a shear thinning agent, and a copolymer represented by the following structural formulas (1), (2), and (3). To do.

[L, m, n in the formula satisfies m / m + n ≧ 0.8 and satisfies l / l + m + n ≧ 0.1. X is x ≧ 1. ]
Furthermore, it is a requirement that the colorant is a microcapsule pigment containing a reversible thermochromic composition.
Furthermore, a ballpoint pen incorporating any of the above-described water-based ink compositions for ballpoint pens is a requirement.

  According to the present invention, even a water-based ink using a shear thinning agent is excellent in dry-up performance of the nib, so that it does not cause precipitation or the like and does not cause poor handwriting such as blurring. Water-based ink composition for ballpoint pens and a ballpoint pen incorporating the same.

The copolymer of the structural formulas (1), (2) and (3) added to the water-based ink of the present invention is a nonionic modified polyvinyl alcohol having a hydrophilic ethylene oxide group in the side chain, By combining the structures of (1), (2), and (3), it becomes a partially saponified polyvinyl alcohol having an acetic acid group, and has higher solubility in water and excellent flexibility than general polyvinyl alcohol. The film can be formed. In particular, the stability in the dissolved state is extremely high due to the hydrophilicity of the ethylene oxide group.
Therefore, by adding it to the water-based ink composition, a film derived from the copolymer is formed on the tip end surface, and evaporation of moisture from the tip end is suppressed. In addition, since the film is easily broken by the rotation of the ball at the time of writing, sufficient ink discharge can be maintained. In addition, since the said copolymer has high water solubility, it expresses the effect stabilized for a long time, without precipitating with a nib.
Moreover, as a saponification degree of the said copolymer, the thing of 80-99.5 mol% is used suitably.

The copolymer can be added in an amount of 0.01 to 10% by weight, preferably 0.5 to 5% by weight, based on the total amount of the ink composition.
If it is less than 0.01% by weight, it is difficult to provide sufficient dry-up resistance, and even if added in excess of 10% by weight, no more than a certain level of improvement in dry-up resistance is observed. The above addition is not 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 will be exemplified below.
As the dye, an acid dye, a basic dye, a direct dye, or 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.

Examples of the pigment include inorganic pigments such as carbon black and ultramarine blue, and organic pigments such as copper phthalocyanine blue and benzidine yellow, as well as water-dispersed pigments that are finely and stably dispersed in an aqueous medium in advance using a surfactant or the like. For example, C.I. I. Pigment Blue 15: 3B [Product Name: S.P. S. Blue GLL, pigment content 22%, manufactured by Sanyo Color Co., Ltd.], C.I. I. Pigment Red 146 [Product Name: S.P. S. Pink FBL, pigment content 21.5%, manufactured by Sanyo Dye Co., Ltd.], C.I. I. Pigment Yellow 81 [Product name: TC Yellow FG, pigment content about 30%, manufactured by Dainichi Seika Kogyo Co., Ltd.], C.I. I. Pigment Red220 / 166 [Product name: TC Red FG, pigment content: about 35%, manufactured by Dainichi Seika Kogyo Co., Ltd.].
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, pearl pigments, gold and silver metallic pigments, luminous pigments, white pigments such as titanium dioxide used in correction pens, metal powders such as aluminum, thermochromic compositions, photochromic compositions, and fragrances Examples thereof include capsule pigments directly or microencapsulated.

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 heat decolorable microcapsule pigment in which a reversible thermochromic composition having relatively small characteristics (ΔH = 1 to 7 ° C.) is encapsulated in a microcapsule 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. Microcapsule pigment was contained a reversible thermochromic composition heated decolorizable having chroma memory property can be applied.

  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 may be used singly or in combination of two or more, and is used in the range of 1 to 35% by weight, preferably 2 to 30% by weight in the ink composition.
In general, when a thermochromic pigment is used, the present invention is particularly useful because the solid content in the ink tends to increase and the ink tends to dry up.

Further, if necessary, a conventional general-purpose water-soluble organic solvent compatible with water can be used. 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, 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.

  As the shear thinning agent, a substance that is soluble or dispersible in water is effective, and xanthan gum, welan gum, zetasy gum, dieutan gum, macrohomopsis gum, and a constituent monosaccharide is an organic acid-modified heterogeneous of glucose and galactose. Succinoglycan, which is a polysaccharide (average molecular weight: about 100 to 8 million), guar gum, locust bean gum and its derivatives, hydroxyethyl cellulose, alkyl alginate, alkyl ester of methacrylic acid, molecular weight 100,000 to 150,000 Polymers, glucomannan, carbohydrates having gelling ability extracted from seaweed such as agar and carrageenan, cross-linked poly N-vinyl-carboxylic acid amide, benzylidene sorbitol and benzylidene xylitol or their derivatives, cross-linkable acrylic acid Coalescence Examples thereof include alkali thickening acrylic thickeners, inorganic fine particles, nonionic surfactants having an HLB value of 8 to 12, and metal salts and amine salts of dialkylsulfosuccinic acid. Furthermore, N-alkyl is included in the ink composition. -2-Pyrrolidone and an anionic surfactant may be used in combination.

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) A preservative or antifungal agent such as pyridine, an antifoaming agent, a fluorine-based surfactant or a nonionic surfactant that improves ink permeability may be used. In addition, other wetting agents such as sorbitol, mannitol, sucrose, glucose, reduced starch hydrolyzate, urea, sodium pyrophosphate can be used in combination.
Furthermore, a lubricant can be added, such as metal soap, polyalkylene glycol fatty acid ester, ethylene oxide addition type cationic surfactant, phosphate ester 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, dimethyldithiocarbamate, N-acyl-L -A condensate of glutamic acid and L-lysine or a salt thereof is used.
Ascorbic acid, erythorbic acid, α-tocopherol, catechins, synthetic polyphenol, kojic acid, alkylhydroxylamine, oxime derivative, α-glucosylrutin, α-lipoic acid, phosphonate, phosphinate, sulfite, sulfoxylate It is also possible to chemically remove bubbles by adding dithionite, thiosulfate, thiourea dioxide or the like.
Further, oligomers of N-vinyl-2-pyrrolidone, oligomers of N-vinyl-2-piperidone, N-vinyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, ε-caprolactam, N-vinyl-ε-caprolactam By adding a thickening inhibitor such as an oligomer, it is possible to enhance the function in the intruding form.

The water-based ink composition is filled in a ballpoint pen with a ballpoint tip attached to the writing tip.
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 an ink backflow prevention body in close contact with the ink end face.

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.
Moreover, a cemented carbide, stainless steel, a ruby, a ceramic, etc. can be applied to the said ball | bowl, and the thing of the range of diameter 0.1mm-2.0mm is used suitably.

For example, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, or polyethylene terephthalate is preferably used as the ink storage tube for storing the water-based ink composition in terms 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 amount of ink, 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.

Further, an ink backflow preventer (liquid stopper) is filled in the rear end portion of the ink composition filled in the ink containing tube.
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 co-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 ballpoint pen may be either a cap-type or a retractable type, and the retractable ballpoint pen is placed in the shaft cylinder (outer shaft) with the writing tip provided on the ballpoint pen refill exposed to the outside air. Any structure can be used as long as it is housed and the writing tip protrudes from the opening of the shaft cylinder by the operation of the retracting mechanism.
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 retractable ballpoint pen (refill exchange type) in which a plurality of ballpoint pen refills are accommodated in a shaft cylinder.

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 particle diameter of the pigment was measured using a laser diffraction / scattering particle size distribution measuring apparatus [manufactured by Horiba, Ltd .; LA-300], and the average particle diameter (median diameter) was calculated based on the numerical value. Value.

The contents of the raw materials in the table will be described along the note numbers.
(1) Fuji Dye Co., Ltd., trade name: SP Blue 6455, solid content 27.5%
(2) Fuji Pigment Co., Ltd., trade name: SP Black 8065, solid content 25%
(3) Product name: Water Black 100L, manufactured by Orient Chemical Industry Co., Ltd.
(4) 2.0 parts of 3- (4-diethylamino-2-hexyloxyphenyl) -3- (1-ethyl-2-methylindol-3-yl) -4-azaphthalide as component (a), (b) A reversible thermochromic composition comprising 8.0 parts of 2,2-bis (4'-hydroxyphenyl) hexafluoropropane as a component and 50.0 parts of 4-benzyloxyphenylethyl caprate as a component (c) was included. Microcapsule pigment (T ₁ : −14 ° C., T ₂ : −6 ° C., T ₃ : 48 ° C., T ₄ : 60 ° C., ΔH: 64 ° C., average particle size: 2.3 μm, color change from blue to colorless )
(5) Daiichi Kogyo Seiyaku Co., Ltd., trade name: Haitenol N08
(6) Product name: Prisurf AL, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
(7) Arch Chemicals Japan, trade name: Proxel XL-2
(8) Copolymer having a saponification degree of 86.5 to 89.5 mol% in Formula 1 (9) Copolymer having a saponification degree of 98.5 mol% or more in Formula 1 (10) manufactured by Nippon Synthetic Chemical Co., Ltd. Product name: Gohsenol GL-05
(11) Made by Sanki Co., Ltd., trade name: Kelzan

Preparation of Ink Components other than the thickener were added to the water, mixed and stirred, then the thickener was added, stirred at 6000 rpm for 1 hour with a disper at 20 ° C., and filtered to prepare each ink.

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, the mixture was kneaded with three rolls to obtain an ink backflow preventing body.

Preparation of Ballpoint Pen The ink composition of the above examples and comparative examples was filled in a ballpoint pen refill fitted with one end of a polypropylene pipe with a stainless steel tip holding a cemented carbide ball having a diameter of 0.5 mm. After the ink backflow preventive body was disposed on, the ballpoint pen refill was incorporated into a shaft cylinder (cap type) to prepare a sample ballpoint pen.
The following tests were conducted using the sample ballpoint pen.

Cap-off test Each sample ballpoint pen that was confirmed to be writable was exposed to air in the pen tip, left in a 20 ° C environment for 7 days in a horizontal position, and then JIS P3201 writing paper at room temperature. A handwritten on A, 12 spiral circles per line were continuously written. The handwriting state at that time was confirmed visually.

Dissolution stability test Each sample ballpoint pen that was confirmed to be writable was exposed to the air in the air and left in a 20 ° C environment for 7 days in a horizontal position. It was observed visually.
The results of the test are shown in the following table.

The evaluation of the test results is as follows.
Cap-off test ○: Scratch did not occur, or recovered by writing within 3 circles.
X: It is not recovered by writing within 3 circles, or writing is impossible.
Dissolution stability test ○: No abnormality.
X: Precipitate is generated at the tip of the pen tip.

Claims (3)

A water-based ink composition for a ballpoint pen comprising a colorant, water, a shear thinning agent, and a copolymer represented by the following structural formulas (1), (2), and (3).

[L, m, n in the formula satisfies m / m + n ≧ 0.8 and satisfies l / l + m + n ≧ 0.1. X is x ≧ 1. ]   The water-based ink composition for ballpoint pens according to claim 1, wherein the colorant is a microcapsule pigment encapsulating a reversible thermochromic composition.   A ballpoint pen incorporating the water-based ink composition for ballpoint pens according to claim 1 or 2.