JP2017002239A - Aqueous ink composition for ball point pen and ball point pen including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous ink composition for a ball point pen suppressing the corrosion of a super-hard ball with the lapse of time and capable of maintaining excellent writing performance over a long period, and a ball point pen including the same.SOLUTION: Provided is an aqueous ink composition for a ball point pen containing: a coloring agent; water; and one or more kinds of mercaptocarboxylic acids selected from thioglycolic acid, dithiodiglycolic acid and laurylthiopropionate propionic acid or their ammonium salts and alkanolamine salts. Also provided is a ball point pen including the aqueous ink composition for a ball point pen.SELECTED DRAWING: None

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 having excellent ball corrosion resistance and a ballpoint pen incorporating the same.

Conventionally, balls mainly used for the writing tip of a ballpoint pen have been mainly composed of silicon carbide, zirconia oxide, tungsten carbide, etc., but because tungsten carbide is inexpensive and high writing performance is obtained, Cemented carbide balls containing a binder as the main component are widely used.
As the binder, metals such as cobalt, chromium, titanium, nickel are mainly used, and when applied to an aqueous ballpoint pen, the binder may be contained in the ink over time due to corrosive components such as dissolved oxygen in the ink. The binding material is lost. When the bonding material is lost from the balls, crystal grains of tungsten carbide as a main component drop off, or the eluted bonding materials become metal oxides, become insoluble, and adhere to the ball surface again. The corrugation on the surface of the ball becomes large due to the corrosion, resulting in a problem that the rotation of the ball is hindered and the writing feel becomes heavy, the ball seat is worn, the smooth outflow of ink is hindered and the handwriting is faded. Sometimes.
In particular, although cemented carbide balls using cobalt or nickel as a metal binder are highly versatile, they have the drawback of being susceptible to corrosion over time in aqueous ballpoint pens due to the high metal binder content. .
Therefore, as a method for preventing the above-described corrosion over time, a method of adding a sulfide compound or benzotriazole into the ink is disclosed (for example, see Patent Documents 1 and 2).

JP 2004-115684 A Japanese Patent Publication No.49-45333

However, the addition of the sulfide compound may cause problems such as generating an odor depending on the structure of the compound or precipitation due to long-term aging, making it difficult to obtain a sufficient corrosion-inhibiting effect. In addition, although benzotriazole exhibits an effect on copper-based metals, it is difficult to obtain a sufficient effect on cemented carbide, and when added, it tends to cause drying at the nib in a short time. Arise.
Therefore, both of them are insufficient to prevent problems during writing, such as poor writing quality and faint writing.

  The present invention provides a water-based ink composition for a ballpoint pen that can suppress corrosion of a cemented carbide ball over time and maintain excellent writing performance for a long period of time, and a ballpoint pen incorporating the same.

The present invention relates to an aqueous ballpoint pen containing a colorant, water, thioglycolic acid, dithiodiglycolic acid, laurylthiopropionic acid, or one or two or more mercaptocarboxylic acids selected from ammonium salts and alkanolamine salts. An ink composition is a requirement.
Furthermore, it is required that the mercaptocarboxylic acids are added in an amount of 0.1 to 5% by weight in the total amount of the ink composition.
Furthermore, it is a requirement that a ballpoint pen containing any one of the above-mentioned water-based ink compositions for ballpoint pens is used, and that the ballpoint pen uses a cemented carbide ball having cobalt as a binder as a writing tip.

  According to the present invention, it is possible to suppress the ball corrosion phenomenon such as elution of a metal binding material such as cobalt constituting the carbide ball and adhesion of insoluble matter to the ball surface for a long period of time, and to maintain the initial writing performance. Thus, it is possible to provide an ink composition for a water-based ballpoint pen that can maintain a smooth writing feeling for a long period of time without causing blurring or line skipping in the handwriting and a ballpoint pen incorporating the ink composition.

The mercaptocarboxylic acids adsorb on the metal surface to form a film on the ball surface, thereby preventing the corrosive components in the ink from directly acting on the ball surface and effectively suppressing the metal elution described above. It is assumed that it can be done. Moreover, since it exists stably even in an aqueous medium, the corrosion phenomenon on the surface of the carbide ball can be suppressed for a long period of time.
Specific examples of the mercaptocarboxylic acids include thioglycolic acid, dithiodiglycolic acid, laurylthiopropionic acid, ammonium salts thereof, and alkanolamine salts having 1 to 3 carbon atoms.
The mercaptocarboxylic acids can be added in an amount of 0.1 to 5% by weight, preferably 0.3 to 3% by weight, based on the total amount of the ink composition.
If it is less than 0.1% by weight, it is difficult to obtain the desired effect, and even if it is added in excess of 5% by weight, no improvement in the corrosion inhibition effect is observed, so no further addition is required.

As the colorant, all dyes and pigments that can be dissolved or dispersed in an aqueous medium can be used, and specific examples thereof 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 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 alone 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.

If necessary, a 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 2-40 weight%, Preferably it is 5-30 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, 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) Preservatives or antifungal agents such as pyridine, urea, sorbit, mannitol, sucrose, glucose, reduced starch hydrolysates, wetting agents such as sodium pyrophosphate, antifoaming agents, fluorine-based interfaces that improve ink permeability An activator or a nonionic surfactant may be used.
Further, a lubricant can be added, such as metal soap, polyalkylene glycol fatty acid ester, ethylene oxide addition type cationic surfactant, phosphate ester type surfactant, N-acyl amino acid 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, dimethyl A dithiocarbamate, α-lipoic acid, a condensate of N-acyl-L-glutamic acid and L-lysine, a salt thereof, or the like 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.

Furthermore, a shear thinning agent can 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.

Furthermore, when the ink composition is filled in the shaft cylinder (ink storage tube), an ink backflow prevention body (liquid stopper) can be disposed at the rear end of the ink.
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 structure of the tip end (tip) of the ballpoint pen filled with the water-based ink composition for the ballpoint pen has conventionally used a general-purpose mechanism. For example, a ball in which the vicinity of the tip end of a metal pipe is pressed and deformed inward from the outer surface. A chip formed by holding a ball in the holding part, a chip formed by holding a ball in a ball holding part formed by cutting a metal material with a drill or the like, or a metal pipe or metal material A ball or the like held by a chip formed by cutting can be applied forward by a spring body.

For the balls, general-purpose metal balls obtained by sintering 4a, 5a, 6a group metals or their carbides together with a metal such as cobalt or nickel as a binder are used. A hard alloy ball is preferably used. Further, among the metals of the groups 4a, 5a, and 6a or carbides thereof, a cemented carbide ball using tungsten carbide (tungsten carbide) that is chemically stable and has high hardness as a main component is particularly preferably used. . In addition, titanium, vanadium, chromium, tantalum, and their carbides may be included as the metals of 4a, 5a, and 6a.
In general, in the case of using cobalt or nickel as the binder, since these metals are easily eluted in water-based ink, the ball surface becomes rough, and further, tungsten carbide is dropped due to the binder elution. The surface becomes rough. As a result, if the ball rotates while in contact with the ball seat, the wear of the seat becomes severe, so the writing feeling is impaired, and the gap between the ball and the ball holding portion in the axial direction (clearance) increases, causing ink outflow. Increasing the amount tends to cause problems such as thick handwriting and line skipping. However, when the water-based ink of the present invention is applied, the elution of the metal material (binding material) into the ink is suppressed, and the above-described problems are hardly caused.
In particular, the water-based ink composition applied in the present invention is very useful because it is very susceptible to ball corrosion due to contact with an aqueous medium and exerts a very high effect on cemented carbide balls using cobalt as a binder. It will be something.
The balls having a diameter in the range of 0.1 mm to 2.0 mm are preferably used.

The shaft cylinder to which the writing tip is connected directly or via a connecting member is a form capable of containing the water-based ink composition directly or impregnated in an impregnating material (filling), for example, polyethylene, A molded body made of a thermoplastic resin such as polypropylene or polyethylene terephthalate is preferably used in terms of low ink evaporation and productivity, but a metal processed body can also be used. Further, by using a transparent, colored transparent, or translucent molded body, the resin shaft can confirm the ink color, the remaining amount of ink, and the like.
When the ink composition is low in viscosity, the ink composition accommodated in the shaft cylinder includes a method of mounting an ink retaining member at the front of the shaft cylinder and storing the ink composition directly in the shaft cylinder, Examples of the method include impregnating the ink composition into a material body or a fiber processed body.
In addition, the said shaft cylinder may accommodate this refill in an outer shaft as a form of the refill for ball-point pens.

The ballpoint pen using the shaft tube can be applied to either a cap type or a retractable type. The retractable ballpoint pen is stored in the outer shaft with the writing tip provided on the ballpoint pen refill exposed to the outside air, and the writing tip protrudes from the opening of the outer shaft 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 outer shaft rear end portion or the outer shaft side surface, and by pressing the knock portion, the writing pen tip portion of the ballpoint pen refill is caused to protrude or retract from the outer shaft front end opening portion, or on the outer shaft. By pressing the provided clip portion, a configuration in which the writing tip portion of the ballpoint pen refill is projected and retracted from the outer shaft front end opening portion can be exemplified.
The rotary type has a rotating part at the rear part of the outer shaft, and can be exemplified by a configuration in which the writing tip part of the ballpoint pen refill is projected and retracted from the outer shaft front end opening by turning the rotating part.
The slide type has a slide portion on the side surface of the shaft cylinder, and a configuration in which the writing tip portion of the ballpoint pen refill is projected and retracted from the front end opening portion of the outer shaft by operating the slide portion, or a clip portion provided on the outer shaft is provided. By sliding, the structure which makes the writing tip part of a ball-point pen refill appear and disappear from the outer-axis front-end opening part can be illustrated.
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 an outer shaft.

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 191L, manufactured by Orient Chemical Co., Ltd.
(2) Hodogaya Chemical Industry Co., Ltd., trade name: Phloxine (3) Orient Chemical Industry Co., Ltd., trade name: Water Blue 105
(4) 4.5 parts of 2- (2-chloroanilino) -6-di-n-butylaminofluorane as component (a), 1,1-bis (4'-hydroxyphenyl) n- as component (b) Reversible thermochromic composition comprising 4.5 parts of decane, 7.5 parts of 2,2-bis (4'-hydroxyphenyl) hexafluoropropane, and 50.0 parts of 4-benzyloxyphenylethyl caprate as the component (c) Microcapsule pigment encapsulating a product (T ₁ : −20 ° C., T ₂ : −9 ° C., T ₃ : 40 ° C., T ₄ : 57 ° C., ΔH: 63 ° C., average particle size: 2.5 μm, black to colorless Change color)
(5) Arch Chemicals Japan, trade name: Proxel XL-2
(6) Made by Sanki Co., Ltd., trade name: Leozan (7) Thioglycolic acid (8) Laurylthiopropionic acid (9) Thioglycolic acid monoethanolamine (10) Diammonium dithiodiglycolate (11) Thiazolidine

Preparation of Ink A In Examples 1 and 2 and Comparative Examples 1 and 2, each component was added to water, mixed and stirred, then stirred at 400 ° C. for 1 hour at 20 ° C. with a disper and filtered to obtain each ink. Prepared.

Preparation of Ink B In Examples 3 and 4 and Comparative Examples 3 and 4, components other than the shear thinning agent were added to water, mixed and stirred, then the shear thinning agent was added, and the dispersion was performed at 20 ° C. Each ink was prepared by stirring at 400 rpm for 1 hour and filtering.

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.

Production of Ballpoint Pen A The ink compositions of Examples 1 and 2 and Comparative Examples 1 and 2 were accommodated in an ink cartridge. In addition, a stainless steel chip that holds a ball (WC-Co cemented carbide ball) mainly composed of tungsten carbide with a diameter of 0.5 mm is attached to the comb-like ink retaining member (pen core) as a writing tip. Then, after the removable ink cartridge was fitted to the rear of the ink storage member, a sample ballpoint pen A was produced by screwing an outer shaft that covers and protects the ink tank. A detachable cap is fitted on the writing tip portion side.

Production of ballpoint pen B Stainless steel holding the ball B (WC-Co cemented carbide ball) mainly composed of tungsten carbide having a diameter of 0.4 mm with the ink compositions of Examples 3 and 4 and Comparative Examples 3 and 4. A steel tip (accommodating a ball push spring) fills a ballpoint pen refill fitted to one end of a polypropylene pipe, and the ink backflow prevention body is disposed at the rear end of the ballpoint pen refill. The sample ballpoint pen B was fabricated by incorporating it into the formula.

The following tests were conducted using the ink composition and the sample ballpoint pen.
Ball Corrosion Test 5 g of each ink prepared was transferred to a sample bottle, covered with a cemented carbide ball (WC-Co system) having the same composition as that used for the sample ballpoint pen, and then placed in a 70 ° C. environment. Left for 30 days. Then, the state of each ball | bowl surface was confirmed with the optical microscope (1000-times multiplication factor) at room temperature.

Written test Each sample ballpoint pen that was confirmed to be writable was left in a 50 ° C environment for 60 days in a horizontal position, and then written in a handwritten spiral circle on JIS P3201 writing paper A. The feeling and the state of handwriting were confirmed visually.
The results of the test are shown in the following table.

The evaluation of the test results is as follows.
Ball corrosion test ○: No change from the initial stage.
(Triangle | delta): The surface is rough compared with the initial stage.
X: The surface is rough compared with the initial stage, and there is precipitation and deposits.
Writing test ○: Writing was smooth and good handwriting was shown.
X: Written feeling is poor, many blurs and line jumps are seen in the handwriting, and seat wear is large and cannot be written.

Claims (4)

  An aqueous ink composition for ballpoint pens containing a colorant, water, thioglycolic acid, dithiodiglycolic acid, lauryl thiopropionic acid, or one or more mercaptocarboxylic acids selected from ammonium salts and alkanolamine salts thereof.   The aqueous ink composition for ballpoint pens according to claim 1, wherein the mercaptocarboxylic acids are added in an amount of 0.1 to 5% by weight based on the total amount of the ink composition.   A ballpoint pen incorporating the water-based ink composition for ballpoint pens according to claim 1 or 2.   The ball-point pen according to claim 3, wherein the ball-point pen uses a cemented carbide ball having cobalt as a binder as a writing tip.