JP6342796B2 - Water-based ink composition for ballpoint pen and ballpoint pen incorporating the same - Google Patents

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 and a ballpoint pen that are excellent in ink ejection stability during writing.

  Conventionally, water-based inks that have higher surface tension than oil-based inks and poor lubricity have wettability to ballpoint pen tips and pen cores (ink flow rate adjusting members in which a large number of disc bodies are arranged in parallel with comb-like spaces). Therefore, it is easy to cause ink ejection failure by entraining bubbles from the tip of the pen when writing, which may cause problems such as tusks or toggles in the handwriting. In particular, in a ballpoint pen using a pen core, the number of parts is large and the structure is complicated. Therefore, ink following between each member and the comb groove portion is likely to be unstable, and the ink ejection property is difficult to be stabilized. Therefore, a technique for reducing the surface tension of the ink by adding various surfactants to the water-based ink is disclosed (for example, see Patent Documents 1 and 2).

JP 2004-256758 A JP-A-10-298482

  The water-based ink having a reduced surface tension using the surfactant improves the wettability with respect to the tip and the pen core, and thus improves the ink ejection property during writing, but also increases the permeability to paper. The handwriting blur is likely to occur. Further, in the pen core, ink cannot be held when the pressure in the writing instrument changes, and there is a risk of causing ink leakage or the like.

  The present invention does not cause problems such as handwriting bleeding on the paper surface and pen core function deterioration, and can stably maintain ink ejection properties during writing over a long period of time, and can be used to form good handwriting. A water-based ink composition for a ballpoint pen and a ballpoint pen incorporating the same are provided.

The water-based ink composition for ballpoint pens of the present invention is required to contain a colorant, water, and an ester compound represented by the following general formula.
[Chemical 1]
_{C 2 H 5 - (OC 2} H 4) n -O-CO-C 2 H 4 -CO-O- (C 2 H 4 O) n -C 2 H 5
[Wherein n is a natural number of 1 to 3. ]
Furthermore, the ballpoint pen containing the water-based ink composition for the ballpoint pen is a requirement, and the ballpoint pen has a slit-like shape in which a large number of disc bodies are arranged in parallel at intervals of comb grooves, and the disc body vertically penetrates the disc body. It is provided with an ink flow rate adjusting member in which an ink guide groove and a ventilation groove wider than the groove are provided, and an ink guide core for guiding ink from the ink storage section to the pen tip is arranged at the shaft center. Is a requirement.

  According to the present invention, a water-based ink composition for ballpoint pens that can stably maintain ink ejection properties over a long period of time without causing blurring of handwriting on the paper surface, deterioration of pen core performance, etc. It becomes a highly practical ballpoint pen capable of forming good handwriting over the long term.

The ester compound represented by the above general formula, which is added to the water-based ink of the present invention, is a diester formed from succinic acid and (mono, di, tri) ethylene glycol monoethyl ether, and has a hydrophobic group in the structure. It is an amphiphilic substance with a hydrophilic group. Therefore, the solubility in an aqueous medium is high, and it is excellent in stability over time that it does not separate, and high wettability can be imparted to the resin surface such as the ink guiding member and the groove constituting the pen core. . For this reason, ink followability during writing (including not only supply to the pen tip but also continuous supply within the pen core and between the members such as the ink guiding member) is effectively provided, and the ink discharge performance is prolonged. It is possible to form a certain handwriting without blurring or the like by being stably maintained. At that time, since it does not affect the surface tension of the ink, there is no occurrence of handwriting blur or the like.
In particular, succinic acid bisdiethylene glycol ethyl ether (succinic acid bisethoxydiglycol) is preferred as the ester compound because of its extremely high effect on the stability and wettability. Examples of the commercially available product include High Aquastar DCS manufactured by Higher Alcohol Industry Co., Ltd.

The ester compound can be added in the range of 0.1 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 0.1% by weight, it is difficult to provide sufficient ink ejection performance, and even if it is added in excess of 10% by weight, no improvement in performance beyond a certain level is observed. do not do.

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), 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), 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) 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 a 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 a reversible thermochromic composition having color memory applied to the water-based ink, specifically, a complete color development temperature is a temperature that can be obtained only in a freezing room, a cold region, etc., that is, −50 to 0 ° C., Preferably −40 to −5 ° C., more preferably −30 to −10 ° C., and a complete decoloring temperature is obtained from a frictional heat generated by a friction body, a heating body such as a hair dryer, that is, 50 to 95 ° C., It is effective in maintaining the color exhibited in the normal state (daily life temperature range) by specifying the range of preferably 50 to 90 ° C, more preferably 60 to 80 ° C, and the ΔH value of 40 to 100 ° C. Can be made.

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.
Further, when a pigment is used as the colorant, a pigment dispersant can be added as necessary. Examples of the pigment dispersant include surfactants such as anions and nonions, anionic polymers such as polyacrylic acid and styreneacrylic acid, and nonionic polymers such as PVP and PVA.

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, 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, as necessary, inorganic salts such as sodium carbonate, sodium phosphate and sodium acetate, pH adjusters such as organic basic compounds such as water-soluble amine compounds, rust preventives such as tolyltriazole and saponin, coalic acid, 1,2-benzthiazolin-3-one sodium salt, sodium benzoate, sodium dehydroacetate, potassium sorbate, propyl paraoxybenzoate, 2,3,5,6-tetrachloro-4- (methylsulfonyl) pyridine, etc. Preservatives or antifungal agents, urea, sorbit, mannitol, sucrose, glucose, reduced starch hydrolyzate, wetting agents such as sodium pyrophosphate, antifoaming agents, fluorine-based surfactants that improve ink permeability Nonionic surfactants may be used.
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.
In addition, ascorbic acids, erythorbic acids, α-tocopherol, catechins, synthetic polyphenols, kojic acid, alkylhydroxylamine, oxime derivatives, α-glucosylrutin, α-lipoic acid, phosphonate, phosphinate, sulfite, sulfoxyl Bubbles can also be removed chemically by adding acid salts, dithionites, thiosulfates, thiourea dioxide or the like. N-vinyl-2-pyrrolidone oligomer, N-vinyl-2-piperidone oligomer, N-vinyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, ε-caprolactam, N-vinyl-ε-caprolactam oligomer, etc. It is also possible to add a thickening inhibitor.

  Furthermore, if necessary, a shear thinning agent can be added to give the ink an appropriate viscosity for practical use. The shear thinning agent to be used can be appropriately selected from conventionally known agents. Specific examples thereof include xanthan gum, succinoglycan, carrageenan and other polysaccharides, polyacrylic acid, cross-linked acrylic acid, polyvinylacetamide, Nonionic surfactants, anionic surfactants, associative urethane emulsions and the like can be mentioned, and these can be used alone or in combination.

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. A ballpoint pen that communicates with the tip attached to the tip, and the ink backflow prevention body in close contact with the ink end face is attached to the tip of the writing, and the inside of the shaft cylinder (ink storage part A ballpoint pen having a structure in which the ink is directly contained in the ink and a comb groove-shaped ink flow rate adjusting member (pen core) made of a synthetic resin is interposed.

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.

The ink containing body (ink containing tube or ink storage unit) containing the water-based ink composition is, for example, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, etc. In terms of surface. In addition, by using a transparent, colored transparent, or translucent molded body as the ink container, the ink color, the remaining amount of ink, and the like can be confirmed.
The ink container may be a bottomed cylindrical ink storage section (including a cartridge form using a stopper), or a cylindrical ink storage tube may be connected directly or via a connecting member. Good.
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 ink flow rate adjusting member (pen core) applied in the ink storage unit type ballpoint pen is a slit-like ink in which a large number of disc bodies are arranged in parallel at intervals of a comb groove shape and vertically penetrate the disc body in the axial direction. A guide groove and a ventilation groove wider than the groove are provided, and an ink guide member for guiding ink from the ink storage unit to the pen tip is arranged at the shaft center. General synthetic polycarbonate, polypropylene, polyethylene, acrylonitrile-butadiene-styrene copolymer, etc. can be used as long as it is a synthetic resin that can be injection-molded into a comb-groove-like structure of the disc body, but the moldability is particularly high, An acrylonitrile-butadiene-styrene copolymer is preferred from the viewpoint of easily obtaining pen core performance (ink retention). The ink flow rate adjusting member formed of the resin material has low wettability, and in the writing instrument form, a connecting part with the pen tip and the ink storage part is required for guiding the ink. Ink ejection is unstable compared to. Therefore, the water-based ink composition of the present invention is particularly useful.

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 portion 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 contents of the raw materials in the table will be described along the note numbers.
(1) Product name: Water Black 250L, manufactured by Orient Chemical Co., Ltd.
(2) Product name: Brilliant Blue FCF-L, manufactured by Daiwa Kasei Kogyo Co., Ltd.
(3) Sanyo Dye Co., Ltd., trade name: SS Blue GLL
(4) Bisethoxydiglycol succinate, manufactured by Higher Alcohol Industry Co., Ltd., trade name: High Aquastar DCS
(5) Product name: Surflon S-111N, manufactured by ACG Seimi Chemical Co., Ltd.
(6) Nikko Chemicals Co., Ltd., trade name: Nikkor NP-20
(7) Arch Chemicals Japan, trade name: Proxel XL-2
(8) Product name: Prisurf AL, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.

Preparation of ink After adding each component to water and heating at room temperature or in the range of 50 ° C. to 60 ° C. as necessary, mixing and stirring, each ink was stirred at room temperature for 1 hour and filtered. Was prepared.

Preparation of Ballpoint Pen A sample ballpoint pen was prepared by filling 1.0 g of the ink composition in the ink storage part of the pen core type ballpoint pen (manufactured by Pilot Corporation, Hi-Tecpoint V5) and fitting the cap. The pen core of the ballpoint pen was formed by injection molding an ABS resin material.

The following tests were performed using the sample ballpoint pen.
Pen nib performance test Each pen that is held in the pen tip downward state is left at 0 ° C. for 1 hour in the cap fitting state, and then the pen nib comb when the cap is removed and raised to 30 ° C. while the pen nib is in the downward state. The state of ink flowing into the groove and the presence or absence of ink splatter from the pen tip were observed. Further, when the ink was cooled again to 0 ° C., the state of ink collected from the pen core comb groove to the ink storage was observed.

Writing test Each ball-point pen that was confirmed to be writable was checked for ejection stability when a spiral circle was continuously written on JIS P3201 writing paper A with an automatic writing tester. The tester was used at room temperature under a writing load of 50 g, a writing angle of 70 °, and a writing speed of 4 m / min.
The results of each test are shown in the following table.

The evaluation of the test results is as follows.
Pen core performance test ○: Inflow smoothly, but no dropout occurred. Moreover, all the ink in a pen core was collect | recovered favorably.
X: The inflow was irregular and the dropping of the ink occurred or the ink was not collected and remained in the pen core comb groove.
Written test ○: Writing was completed to the end with a fixed discharge amount.
X: Dispersion is seen in the discharge amount or writing becomes impossible on the way.

Claims (3)

A water-based ink composition for ballpoint pens containing a colorant, water, and an ester compound represented by the following general formula.
[Chemical 1]
_{C 2 H 5 - (OC 2} H 4) n -O-CO-C 2 H 4 -CO-O- (C 2 H 4 O) n -C 2 H 5
[Wherein n is a natural number of 1 to 3. ]   The ball-point pen which incorporated the water-based ink composition for ball-point pens of the said Claim 1.   A large number of disc bodies are arranged in parallel at intervals of a comb groove shape, a slit-like ink guide groove passing through the disc body in the axial direction and a ventilation groove wider than the groove are provided, and ink is stored in the shaft center. 3. The ballpoint pen according to claim 2, further comprising an ink flow rate adjusting member in which an ink guide core for guiding ink from the section to the pen tip is disposed.