JP6611225B2 - Ballpoint pen - Google Patents

Description

The present invention relates to a ballpoint pen. Furthermore, it is related with the ball-point pen which incorporated the water-based ink composition which used the pigment as a coloring agent.

Conventionally, water-based ballpoint pen ink compositions containing shear thinning agents such as xanthan gum and polyacrylic acid have been widely used.
This type of ink has a high viscosity when left to stand without applying shear stress and is stably held in the ink container, and when writing, the high shear force of the ball rotating at high speed reduces the viscosity of the ink near the ball. As a result, the ink is ejected 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 and becomes a highly viscous state again, there is an advantage that the blur of the handwriting, which is a defect of the conventional water-based ink, does not occur.
However, among the inks using the shear thinning agent, when a pigment is applied as a colorant, it is difficult to obtain dispersion stability of the pigment over time. Problems such as separation and reduction in handwriting density may occur.

Therefore, proposals have been made to improve the dispersion stability of the pigment by adding a nonionic synthetic resin such as polyvinylpyrrolidone or non-crosslinked polyacrylic acid having a specific molecular weight (for example, see Patent Documents 1 and 2).
However, by adding the additive, the dispersion stability of the pigment is improved, and although the ink viscosity is increased, although the stable state can be maintained without causing sedimentation or aggregation and causing ink separation or the like for a long period of time. , Writing defects such as line breaks and blurring may occur in the handwriting.
In particular, acrylic thickeners such as polyacrylic acid have a low viscosity in a stationary state because of low shear thinning at a viscosity suitable for a ballpoint pen aqueous ink. For this reason, when used as a shear thinning agent, a large amount of addition is required in order to maintain pigment dispersion stability. As a result, the ink viscosity was remarkably increased and writing defects were liable to occur.

JP 2007-211052 A JP 2004-59877 A

The present invention provides a water-based ink composition that is excellent in ink stability due to good pigment dispersion and can form uniform handwriting without blurring even for a pigment-based water-based ink using a shear thinning agent. A ballpoint pen with a built-in object is provided.

The present invention requires a ballpoint pen incorporating a water-based ink composition containing at least one selected from a pigment, water, an acrylic thickener , and nitrilotris (methylenephosphonic acid) or a salt thereof.
Furthermore, the ink containing tube filled with the ink composition and a ballpoint pen tip are connected, and the nitrilotris (methylenephosphonic acid) or a salt thereof is added in an amount of 1% by weight or less in the total amount of the ink composition. As a requirement.

  According to the present invention, even in the case of a pigment-based aqueous ink using a shear thinning agent, excellent ink stability can be obtained by maintaining a good pigment dispersion state by suppressing aggregation and sedimentation of the pigment for a long period of time. The resulting ball-point pen incorporates a water-based ink composition capable of forming good handwriting for a long period of time without causing poor writing such as line breakage and blurring due to an increase in ink viscosity.

The water-based ink composition of the present invention contains any one or more of the aminophosphonic acid compounds together with a pigment and a shear thinning agent in an aqueous medium.
The aminophosphonic acid compound has three or more methylenephosphonic acid groups in the compound, and in addition to nitrilotris (methylenephosphonic acid) and ethylenediaminetetra (methylenephosphonic acid), a methylcarbonyl group, methyl Examples thereof include ethylenediamine tris (methylenephosphonic acid) having a sulfonyl group, methylhydroxy group, ethylhydroxy group to hexylhydroxy group, and salts thereof.
Examples of the salt include alkali metal salts such as lithium, sodium and potassium, and amine salts such as alkanolamine and ammonia.
The aminophosphonic acid compound has three or more methylenephosphonic acid groups in a compound having a nitrogen atom, and thus, even when added in a small amount, it acts as a shear thinning agent in an aqueous medium and is a stable pigment. The dispersed state can be maintained for a long time. Therefore, it is possible to suppress ink separation accompanying pigment sedimentation or the like without changing ink physical properties such as viscosity by addition. In particular, it is a useful additive because it can suppress ink separation without changing ink physical properties even for acrylic thickeners such as polyacrylic acid having a low viscosity in a stationary state and low pigment retention.

The aminophosphonic acid compound is used in an amount of 1% by weight or less, preferably 0.005 to 0.5% by weight, more preferably 0.01 to 0.1% by weight in the total amount of the ink composition, and 0.05% by weight. Even if the addition is less than%, a sufficient effect can be obtained.
Since the aminophosphonic acid compound exhibits the above-mentioned effects in a very small amount, it is difficult to cause a change in ink physical properties before and after the addition. Therefore, it is possible to reliably suppress the precipitation of the pigment that occurs over a long period of time without increasing the ink viscosity. In addition, although it can also add exceeding 1 weight%, since the improvement of an effect is not seen, 1 weight% or less is enough.

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.

  Furthermore, a pigment dispersant can be added as needed. As the pigment dispersant, surfactants such as anions and nonions, anionic polymers such as polyacrylic acid and styreneacrylic acid, and nonionic polymers such as PVP and PVA are used.

Moreover, it is also possible to use together with the said pigment the dye which can be melt | dissolved in an aqueous medium.
As the dye, acid dyes, basic dyes, direct dyes and the like can be applied, and general-purpose ones can be selected and used.
The colorant containing the pigment may be used singly or in combination of two or more, and is used in the range of 1 to 25% by weight, preferably 2 to 15% by weight in the ink composition.

Examples of the shear thinning agent include xanthan gum, welan gum, lanthanum gum, zetasy gum, diyutan gum, macrohomopsis gum, pullulan, and succinoglycan whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose (average molecular weight of about 1-8 million), guar gum, locust bean gum and its derivatives, acrylic thickeners such as polyacrylic acid and cross-linked acrylic acid, hydroxyethyl cellulose, alkyl alginate, alkyl ester of methacrylic acid 100,000 to 150,000 polymers, glucomannan, carbohydrates having gelling ability extracted from seaweeds such as agar and carrageenan, poly N-vinyl-carboxylic acid amide cross-linked products, benzylidene sorbitol and benzylidene xylitol or These derivatives, the HLB value of 8 to 12 nonionic surfactant, a metal salt or amine salt of a dialkyl sulfosuccinic acid and the like.
In particular, acrylic thickeners are useful materials because they have a lower viscosity in the stationary state than other materials, and therefore are easily reduced in viscosity by rotation of the ball by writing to easily obtain a smooth writing feeling. Ink stability when using a pigment is difficult to obtain. Therefore, the composition of the present invention provides a particularly useful material because long-term ink stability can be obtained.
Examples of the acrylic thickener include polyacrylic acid and cross-linked acrylic acid described above, sodium salts and ammonium salts thereof, acrylic acid copolymers, acrylic acid-methacrylic acid copolymers, and the like. An emulsion is mentioned.

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%.

  Further, a water-soluble resin can be added in order to impart adhesion to the paper surface or viscosity. 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) 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, catechin, 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.

Furthermore, an ink backflow preventer (liquid stopper) can be 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 contents of the raw materials in the table will be described along the note numbers.
(1) Aqueous pigment dispersion containing 20% carbon black and 8% polyvinyl alcohol (2) C.I. I. An aqueous pigment dispersion containing 20% of Pigment Red 213 and 5% of an anionic surfactant (3) An aqueous pigment dispersion containing 20% of phthalocyanine green (CI Pigment Green 7) and 8% of a nonionic surfactant (4) Wako Pure Chemical Industries, Ltd., trade name: Hibiswako 104
(5) Made by Dow Chemical Japan Co., Ltd., trade name: Primal ASE60: solid content 28%
(6) Made by Sanki Co., Ltd., trade name: Kelzan (7) Nitrilotris (methylenephosphonic acid)
(8) Nitrilotris (methylenephosphonic acid) sodium salt (9) Ethylenediaminetetra (methylenephosphonic acid)
(10) Ethylenediaminetetra (methylenephosphonic acid) sodium salt (11) Product name: K-15, manufactured by ISP
(12) Etidronic acid (13) 2-phosphono-1,2,4-butanetricarboxylic acid (14) Lonza Japan Co., Ltd., trade name: Proxel XL-2

Preparation of ink Add ingredients other than shear thinning agent to water, mix and stir, add shear thinning agent, stir at 20 ° C with disper at 400 rpm for 1 hour, and filter each ink. Was prepared.

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 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, and the rear end was filled A ballpoint pen refill was prepared by arranging the ink backflow preventer, and a sample ballpoint pen was prepared by incorporating the ballpoint refill into a shaft cylinder (rear end knock type).
The following tests were conducted using the sample ballpoint pen and each ink composition.

Ink Stability Test Each ink composition was put in a 20 mL glass bottle and sealed, and then left in an environment of 70 ° C. for 14 days. Then, the state of the ink in a glass bottle was confirmed visually at room temperature.

Written test Each sample ballpoint pen that was confirmed to be writable was left in an environment of 50 ° C. for 60 days. After that, 12 lines of spiral circles were written on the old JIS P3201 writing paper A by handwriting at room temperature for 3 consecutive lines. The handwriting state at that time was confirmed visually.
The results of the test are shown in the following table.

The evaluation of the test results is as follows.
Ink stability test ○: Pigment sedimentation or the like is not observed, and is in the same state as the initial stage.
X: Phase separation accompanying aggregation and sedimentation of the pigment is observed.
Written test ○: A good handwriting was shown.
X: Scratch and line breakage were seen in the handwriting, or writing was impossible.

Claims (3)

A ballpoint pen containing a water-based ink composition containing at least one selected from a pigment, water, an acrylic thickener , and nitrilotris (methylenephosphonic acid) or a salt thereof. 2. The ballpoint pen according to claim 1, which is in the form of a refill in which an ink containing tube filled with an ink composition and a ballpoint pen tip are connected. The ballpoint pen according to claim 1 or 2, wherein the nitrilotris (methylene phosphonic acid) or a salt thereof is added in an amount of 1% by weight or less based on the total amount of the ink composition.