JP2006123278A - Tarnishable ball-point pen and writing utensil set using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tarnishable ball-point pen, which has excellent initial writing-out properties, can get a dark holograph by a light writing touch and satisfy the drying properties of the holograph and is excellent in practicality and convenience by tarnishing or decolorizing the holograph and a writing utensil set using the tarnishable ball-point pen. <P>SOLUTION: This tarnishable ball-point pen formed by directly charging an ink and an ink anti-backflowing body in an ink housing tube equipped with a ball-point pen tip. The ink is made of water and a dye, which is tarnished or decolorized by a reducing agent and has a viscosity of 3-160 mPa s measured at 20°C by a E type rotational viscometer at 100 rpm and, at the same time, is a shear-thinning tarnishable ink having a shear-thinning index of 0.6-0.99 or a non-shear-thinning tarnishable ink having the viscosity of 1-50 mPa s and has pH of 1-6. Further, the writing utensil set employing the tarnishable ball-point pen is dealt. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a color-changing ballpoint pen and a writing instrument set using the same. More specifically, the present invention relates to a color-changing ballpoint pen capable of forming a handwriting that can be changed or erased by application of a color-changing liquid, and a writing instrument set comprising the ballpoint pen and the color-changing applicator.

Conventionally, there has been disclosed an oil-based ballpoint pen in which ink is directly filled in an ink containing tube in which a ballpoint pen tip that holds a ball at the tip is fitted at one end.
The oil-based ballpoint pen has a small number of parts and is inexpensive, but because of its structure, the gap is made very small in order to suppress ink dripping from the gap between the ball and the tip of the tip when the ballpoint pen is downward. In addition, the ink has a high viscosity of about 10 to 20 Pa · s at room temperature. Therefore, the writing feeling is heavy and the handwriting tends to be thin.
In addition, the water-based ballpoint pen filled with the low-viscosity water-based ink has a light writing feeling and a dark handwriting, but requires a mechanism for controlling the outflow of the ink, and has a drawback that the structure is complicated and the cost is high.
In recent years, a shear-thinning ballpoint pen in which the oil-based ballpoint pen mechanism is filled with a shear-thinning water-based ink and an ink backflow preventer has been disclosed (for example, see Patent Document 1).
The shear-thinning ballpoint pen is inexpensive and has a simple structure, similar to an oil-based ballpoint pen, and the stored ink has a high viscosity when it is left to stand without being subjected to shear stress, and is stably held in the ballpoint pen mechanism. At the time of writing, only the ink in the vicinity of the ball has a low viscosity due to the high shearing force of the ball rotating at high speed, and as a result, the ink smoothly passes through the gap between the ball and the ball housing portion by capillary force. Has a function of transferring ink.
Therefore, although a dark handwriting can be obtained and the writing feeling can be made lighter than that of an oil-based ballpoint pen, the shear-thinning ink is used to reduce ink shear to prevent ink leakage from the writing tip. The viscosity index is adjusted to about 0.1 to 0.6, and the ink viscosity at the time of writing with a shearing force is not as high as that of oil-based ink, but the writing feeling is inferior to that of a water-based ballpoint pen, and the initial At the time of writing, the ink was difficult to transfer to the ball.
Furthermore, the handwriting with the shear-thinning ink is difficult to dry and tends to be contaminated by transferring to a blank portion of the writing surface by finger touch or rubbing between papers.
Japanese Patent Publication No. 1-16437

  The present invention is intended to solve the problems of the conventional ballpoint pen described above, that is, it is relatively simple and inexpensive, can form a dark handwriting with a light writing feeling, initial writing and handwriting dryness It is intended to provide a color-changing ballpoint pen capable of satisfying the above and discoloring or erasing the handwriting and a writing instrument set using the same.

The present invention is a ballpoint pen in which an ink containing tube including a ballpoint pen tip holding a ball at a tip portion is directly filled with ink and an ink backflow prevention body, and the ink is discolored by water and a reducing agent. Alternatively, the viscosity at 100 rpm in an E-type rotational viscometer at 20 ° C. comprising at least a dye to be decolored is in the range of 3 to 160 mPa · s, and the shear thinning index is in the range of 0.6 to 0.99. A certain shear-thinning color-changing ink or a non-shear-thinning color-changing ink having a viscosity in the range of 1 to 50 mPa · s and a color-changing ballpoint pen having a pH in the range of 1 to 6 are required.
Furthermore, the discolorable ink contains polyvinyl alcohol or polyvinylpyrrolidone, the pH of the ink is in the range of 1 to 4, the ink containing tube also serves as a shaft tube, and the ink containing tube is pivoted. It is accommodated in the cylinder, the ballpoint pen tip can be projected and retracted from the tip hole of the shaft cylinder, the clip is formed on the outer surface of the front of the shaft cylinder, the ink backflow prevention body is made of base oil and thickening A point where the tan δ in the viscoelasticity measurement exceeds 1 (ω) is in the range of 20 rad / s ≦ ω ≦ 450 rad / s, and a resilient member for projecting the rear end of the ball forward is provided. When not writing, the ball is pressed against the inner edge of the tip to bring it into close contact, and when writing, the ball is retracted by writing pressure so that ink can flow out. A discoloration applicator containing a liquid, and the discoloration applicator is a marking pen having a marking pen tip at a tip portion or a ball pen having a ball pen tip having a ball held at a tip portion. That is, the color changing applicator is a ballpoint pen, and the diameter (A) of the ball provided on the ballpoint pen and the diameter (B) of the ball provided on the color changeable ballpoint pen satisfy the following formula (1), etc. Is a requirement.
A ≧ B (1)
Furthermore, the writing tool set comprising the color-changing ballpoint pen and a color-changing applicator containing a color-changing liquid is a requirement, and the color-changing applicator is a marking pen provided with a marking pen tip at the tip, or the tip A ballpoint pen having a ballpoint pen tip holding the ball, the discoloring applicator is a ballpoint pen, the diameter of the ball provided on the ballpoint pen (A), and the diameter of the ball provided on the color changeable ballpoint pen (B) satisfies the following formula (2),
A ≧ B (2)
It is a requirement to be composed of a plurality of color-changing ballpoint pens and color-changing applicators having different color tones.

  The present invention is excellent in initial writing, a dark handwriting is obtained with a light writing feeling, satisfies the dryness of the handwriting, and is a color-changing ballpoint pen excellent in practicality and convenience that can discolor or decolor the handwriting. And a writing instrument set using the same.

The colorant contained in the ink is a dye that is discolored or decolored by a reducing agent, and is a methine dye, trimethylmethane dye, diphenylmethane dye, triphenylmethane dye, xanthene dye, or cyanine dye. Azo dyes, anthraquinone dyes, cyanine dyes, and the like can be used.
Specific examples of the dye include C.I. I. Basic Blue 1, C.I. I. Basic Blue 3, C.I. I. Basic Blue 7, C.I. I. Basic Blue 54, C.I. I. Basic Blue 65, C.I. I. Basic Blue 69, C.I. I. Basic Orange 21, C.I. I. Basic Orange 46, C.I. I. Basic Red 13, C.I. I. Basic Red 14, C.I. I. Basic Red 37, C.I. I. Basic Red 49, C.I. I. Basic Green 1, C.I. I. Basic Green 4, C.I. I. Basic Violet 1, C.I. I. Basic Violet 10, C.I. I. Basic Violet 15, C.I. I. Basic Violet 27, C.I. I. Basic Yellow 49, C.I. I. Acid Blue 93, C.I. I. Acid Red 92, C.I. I. Acid Green 3, C.I. I. Acid Violet 19, C.I. I. Acid yellow 23 can be exemplified.
In addition, by using together with a dye that is discolored or decolored by the reducing agent and a dye or pigment that is difficult to be discolored by the reducing agent, a handwriting in which the color tone of the dye is mixed during writing is visually recognized, and the color changing liquid is applied to the handwriting. By adhering, one of the dyes can be discolored or decolored so that a handwriting with a different color tone can be visually recognized.

In addition to water, conventional water-soluble organic solvents can be added to the ink, and ethanol, propanol, butanol, glycerin, sorbitol, triethanolamine, diethanolamine, monoethanolamine, ethylene glycol, diethylene glycol Thiodiethylene glycol, hexylene glycol, 1,3-butanediol, neoprene glycol, polyethylene glycol, propylene glycol, butylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether diethylene glycol monoethyl ether, ethylene glycol monomethyl ether Acetate, propylene glycol monomethyl ether, propylene glycol Examples thereof include coal monoethyl ether, 2-pyrrolidone, N-methyl-2-pyrrolidone and the like.
In addition, the said water-soluble organic solvent can also use 1 type (s) or 2 or more types together, and is used in 2-50 weight%, Preferably it is 5-35 weight%.

In addition, in order to make the coloring property of a dye favorable in ink, it is necessary to make pH of ink 1-6.
Therefore, if the pH of the ink needs to be adjusted in the acidic region, an acidic substance can be added, formic acid, acetic acid, propionic acid, lactic acid, oxalic acid, succinic acid, malic acid, citric acid, tartaric acid, phosphoric acid. In addition, sulfonic acid such as paratoluenesulfonic acid, hydrochloric acid, sulfuric acid, nitric acid and the like are applied.
In particular, an organic acid that has little influence on the wear of the ballpoint pen tip and the color tone of the ink is preferably used.

The ink has a viscosity measured at 100 rpm (20 ° C.) of an EM type rotational viscometer in the range of 3 to 160 mPa · s and a shear thinning index [shear stress value (T) and shear rate (j ) Derived from rheological measurement of the value, the empirical formula (T = Kj ^n, where K and n are calculated constants, n value calculated) is 0.6 to 0.99 , Preferably 0.8 to 0.99, more preferably 0.9 to 0.99 in the shear-thinning color changing ink, or the viscosity is 1 to 50 mPa · s, preferably 1 to 30 mPa · s, more Preferably, non-shear thinning discoloration-changing ink in the range of 1 to 10 mPa · s is applied.

Examples of the thickener used as necessary to impart shear thinning viscosity to the ink or to impart a desired ink viscosity include water-soluble or dispersible xanthan gum, welan gum, and constituent monosaccharides and glucose. Mainly composed of succinoglycan (average molecular weight of about 1 to 8 million), guar gum, locust bean gum and its derivatives, hydroxyethyl cellulose, alkyl alginates, and alkyl esters of methacrylic acid, which are organic acid-modified heteropolysaccharides of galactose Polymer having a molecular weight of 100,000 to 150,000, thickening polysaccharide having gelling ability extracted from seaweed such as glucomannan, agar and carrageenin, benzylidene sorbitol and benzylidene xylitol or their derivatives, crosslinkable acrylic acid polymer, Inorganic fine particles, polyglycerin fat Nonionic surfactants having an HLB value of 8 to 12, such as acid esters, polyoxyethylene sorbitan fatty acid esters, polyethylene glycol fatty acid esters, polyoxyethylene alkyl ethers / polyoxypropylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, fatty acid amides , Salts of dialkyl or dialkenylsulfosuccinic acid, a mixture of N-alkyl-2-pyrrolidone and an anionic surfactant, a mixture of polyvinyl alcohol and an acrylic resin, and the like can be used alone or in combination.
Furthermore, water-soluble resins can also be used, and examples thereof include alkyd resins, acrylic resins, styrene maleic acid copolymers, cellulose derivatives, polyvinyl pyrrolidone, polyvinyl alcohol, and dextrin.
Ink shear thinning is a rheological property that has a high viscosity and is difficult to flow in a static state or when stress is low, and it exhibits low fluidity and good fluidity when stress increases. It means liquidity called pseudo plasticity. Therefore, the ink has a three-dimensional structure that is temporarily destroyed under high shearing stress at the time of writing and the viscosity of the ink is lowered, and the ink at the writing tip becomes a low-viscosity ink suitable for writing and is transferred to the paper surface. When not writing, the viscosity of the ink becomes high, so that leakage of the ink can be prevented, and separation and backflow of the ink can be prevented. Also, the ink physical properties can be kept stable over time.

Among the thickeners, polyvinyl pyrrolidone and polyvinyl alcohol are preferably used because they function stably even when the ink is in an acidic region and exhibit a desired ink viscosity.
In particular, in a system in which a dye having an ink pH of 1 to 4 shows a good color development state, the polyvinyl pyrrolidone and polyvinyl alcohol are excessive even at the initial stage and after the lapse of time, although other thickeners hardly exhibit a sufficient function. Thus, the desired ink viscosity can be maintained without causing an increase in viscosity or a decrease in viscosity.

In addition, as long as it does not affect the color development and decoloration of the dye, if necessary, anticorrosive agent, antiseptic agent such as coal acid or antifungal agent, surfactant, wetting agent, antifoaming agent such as methylpolysiloxane, lubrication You may use additives, such as an agent.
Examples of the lubricant include metal soap, polyalkylene glycol fatty acid ester, ethylene oxide addition type cationic activator, phosphate ester activator, thiocarbamate, dimethyldithiocarbamate and the like.

The ballpoint pen tip that constitutes the ballpoint pen has a conventional general-purpose tip mechanism, for example, a tip that is formed by cutting a metal to form a ball receiving seat and an ink lead-out portion, and a plurality of inner sides on the inner surface near the tip of a metal pipe. Protrusions are provided by pressing deformation from the outer surface, and between the inward projections, a chip formed with an ink outflow gap extending radially outward from the central part in the radial direction, a metal or plastic chip is made of resin A chip provided with a ball seat or the like can be applied. Particularly, a chip formed by pressing deformation has a relatively small contact area with the rear end of the ball, and can provide a smooth writing feeling with a low writing pressure.
Balls held by the ballpoint pen tip are effectively balls having an outer diameter of 0.2 to 3.0 mm, such as cemented carbide, stainless steel, ruby, ceramic, and the like. The movable distance in the radial direction is preferably in the range of 10 to 50 μm, and the movable distance in the axial direction of the ball is preferably in the range of 10 to 30 μm.
The ballpoint pen tip is provided with a resilient member for projecting the rear end of the ball forward in the tip. When not writing, the ball is pressed against the inner edge of the tip of the tip to bring it into close contact, and when writing, it is It is preferable that the ball is retracted so that ink can flow out, and ink leakage when not in use can be suppressed.
Examples of the elastic member include a metal thin wire spring, a member provided with a straight portion (rod portion) at one end of the spring, and a linear plastic processed body. The elastic member can be pressed by an elastic force of 15 to 45 g. Applied.

The ink storage tube connected to the ballpoint pen tip directly or via a connecting member is a general-purpose cylindrical molded member, for example, a molded member made of a thermoplastic resin such as polyethylene, polypropylene, polyethylene terephthalate, etc. It is preferably used in terms of low evaporation and productivity.
Further, the ink containing tube having an inner diameter of 2.5 to 10 mm is preferably used.
Furthermore, 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.
The ink storage tube may be accommodated in the shaft cylinder as a form of refill, or the shaft cylinder itself having a tip attached to the tip may be used as an ink storage tube, and ink may be directly filled into the shaft cylinder.
The ballpoint pen of the type that accommodates the refill in the shaft cylinder is a knock type such as a rear end knock or a side knock or a rotary type that allows the refill that does not require a cap to appear and disappear, in addition to a ballpoint pen that is configured to mount a cap. It may be a ballpoint pen.

An ink backflow preventer is filled at the rear end of the ink stored in the ink storage tube.
The ink backflow preventer comprises a non-volatile liquid and / or a hardly volatile liquid (base oil).
Specifically, petroleum jelly, spindle oil, castor oil, olive oil, refined mineral oil, liquid paraffin, polybutene, α-olefin, α-olefin oligomer or co-oligomer, dimethyl silicone oil, methylphenyl silicone oil, amino-modified silicone oil, poly Ether-modified silicone oil, fatty acid-modified silicone oil and the like can be mentioned, and one kind or two or more kinds can be used in combination.

It is preferable to add a gelling agent to the nonvolatile liquid and / or the hardly volatile liquid to increase the viscosity to a suitable viscosity. The surface of the silica is hydrophobized, the surface is methylated fine particle silica, and aluminum silicate. , Swellable mica, hydrophobic thickeners such as bentonite and montmorillonite, fatty acid metal soaps such as magnesium stearate, calcium stearate, aluminum stearate, zinc stearate, tribenzylidene sorbitol, fatty acid amide, amide modified Examples include dextrin compounds such as polyethylene wax, hydrogenated castor oil, fatty acid dextrin, and cellulose compounds.
Polybutene or silicone oil is preferably used as the base oil of the ink backflow preventer, and fatty acid amide or silica is preferably used as the thickener.
The ink backflow preventer preferably has a point (ω) where tan δ in viscoelasticity measurement exceeds 1 in the range of 20 rad / s ≦ ω ≦ 450 rad / s.
More specifically, the ink contained therein has a viscosity at 100 ° C. in an E-type rotational viscometer at 20 ° C. in the range of 3 to 160 mPa · s and a shear thinning index of 0.6 to 0.99. Is a shear-thinning color-changing ink having a viscosity of 1 to 50 mPa · s or a non-shearing-thickening color-changing ink having a viscosity of 1 to 50 mPa · s. Is inferior in impact resistance as compared with conventional shear thinning ink adjusted to about 0.1 to 0.6. Therefore, ink is likely to leak out from the rear part of the ink containing tube, and writing may become impossible or the commercial value may be impaired.
Therefore, the ink backflow preventer disposed at the rear end of the ink is imparted with impact resistance so as to solve the above-mentioned problems.
The ink backflow preventive body exhibits viscoelasticity and exhibits an intermediate property between an elastic response and a viscous response.
The viscoelasticity is measured by a rheometer vibration method. Tan δ is obtained by dividing the value of the loss elastic modulus by the value of the storage elastic modulus. When this value is low (tan δ <1), the elastic property is high. In addition, the viscosity characteristics are lowered. On the other hand, when this value is high (tan δ> 1), the elastic characteristics are low and the viscosity characteristics are high.
In the above-described viscoelasticity measurement, the region where the angular frequency (rad / s) is 20 or more is a region close to a state where an impact such as a drop is applied to the writing instrument.
Therefore, the ink backflow preventive body showing viscoelasticity with tan δ exceeding 1 at 20 rad / s can satisfy the impact resistance depending on the strength of the viscous response.
The point where tan δ exceeds 1 is 20 rad / s or more, but if it exceeds 450 rad / s, the elastic response becomes strong and the ink followability tends to be deteriorated, resulting in poor ink discharge.
Therefore, both the impact resistance and the writing performance can be satisfied by adjusting the point (ω) where tan δ of the ink backflow preventive body exceeds 1 to the range of 20 rad / s ≦ ω ≦ 450 rad / s.
A resin solid stopper can be used in combination with the ink backflow preventer.

Specific examples of the reducing agent for changing or erasing the color-changeable ballpoint pen ink include sodium sulfite, potassium sulfite, lithium sulfite, calcium sulfite, ammonium sulfite, zinc sulfite, sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate, Sodium hypochlorite, tin chloride, hydrosulfite and the like can be exemplified, and sodium sulfite is preferably used from the viewpoint of safety and discoloration or decoloring performance.
Moreover, an organic solvent and various additives can be mix | blended with the said discoloration liquid as needed.
As the color change applicator, the applicator has a simple structure for attaching the stored color change liquid directly to the handwriting from the opening, and has a cap provided with a liquid absorbing liquid such as a brush in the opening, and the cap is fitted in the state where the cap is fitted. An applicator having a structure in which the liquid-absorbing liquid is impregnated with the color-changing liquid in the container and the liquid-absorbing liquid is brought into contact with the handwriting to apply the color-changing liquid can be exemplified.
Also, it may be an applicator having the structure of a writing instrument, and an ink occlusion composed of a fiber bundle housed in a writing tip with a fiber tip, felt tip, plastic tip, brush tip, etc. attached to the applicator. A structure in which the body is impregnated with the color changing liquid and the color changing liquid is supplied to the writing tip part, the ink is directly stored in the shaft tube, and a liquid flow rate adjusting member composed of a comb groove-like liquid flow rate adjusting member or a fiber bundle is interposed. Marking pen, brush pen, shaft with a structure that supplies a predetermined amount of color-changing liquid to the writing tip, and a structure that supplies the color-changing liquid directly to the writing tip by a valve mechanism A structure that impregnates the color changing liquid into the occlusion body consisting of fiber bundles contained in the cylinder and supplies the color changing liquid to the writing tip with the ball-point pen tip. Liquid consisting of members and fiber bundles A structure for supplying a predetermined amount of the color changing liquid to the writing tip through the flow rate adjusting member, and a housing tube filled with the color changing liquid in the shaft cylinder, the housing pipe communicating with the ballpoint pen tip, and further the color changing A ballpoint pen having a structure in which a liquid stopper for preventing a backflow is disposed at the rear end of the liquid can be exemplified.

The discoloring applicator (ball pen, marking pen, brush pen, etc.) is provided in part of the discoloring ball pen, specifically the rear part of the ball pen (so-called double-headed writing instrument structure), and the handwriting obtained by writing is used. It can be set as the ball-point pen excellent in the portability which can be discolored or decolored with a single writing instrument.
When the discoloration liquid is housed in a writing instrument-shaped applicator for practical use, an applicator that can form a handwriting width wider than the width of the handwriting formed by the color-changing ballpoint pen can effectively discolor or erase the handwriting. Can be colored.
When the applicator provided at the rear portion is in the form of a ballpoint pen, the diameter (A) of the ball provided on the ballpoint pen and the diameter (B) of the ball provided on the color changing ballpoint pen satisfy the following relational expression (1). It is preferable.
A ≧ B (1)
Further, in the relational expression, A> B is more preferable.

In addition, a writing instrument set can be obtained in combination with a color changing applicator and a color changing ballpoint pen.
The writing instrument set may be composed of a single color-changing ballpoint pen and a color-changing applicator, but a plurality of color-changing ballpoint pens having different color tones or a plurality of color-changing ballpoint pens having different handwriting widths and a color-changing applicator are combined. By using the writing instrument set, it is possible to form a writing instrument set having a variety of handwriting and patterns, and to obtain a writing instrument set having an unexpected property capable of changing or erasing the handwriting or the pattern.
When the discoloration liquid is housed in a writing instrument-shaped applicator for practical use, an applicator that can form a handwriting width wider than the width of the handwriting formed by the color-changing ballpoint pen can effectively discolor or erase the handwriting. Can be colored.
When the color change applicator is in the form of a ballpoint pen, the diameter (A) of the ball provided on the ballpoint pen and the diameter (B) of the ball provided on the color changeable ballpoint pen satisfy the following relational expression (2). preferable.
A ≧ B (2)
Further, in the relational expression, A> B is more preferable.

Examples are shown below, but the present invention is not limited to the following examples.
In addition, the part in an Example shows a weight part.
Preparation of shear thinning color changing ink A Red dye 2.0 parts [Hodogaya Chemical Co., Ltd., C.I. I. Basic Red 14]
Phosphate ester surfactant (lubricant) 0.5 part [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Prisurf A212E]
Coal acid (preservative) 0.1 part Citric acid (pH adjuster) 1.0 part Polyvinylpyrrolidone (thickener) 1.5 part [BASF Corp., trade name: Rubytec K90]
Glycerin 15.0 parts Water (ion exchange water) 79.9 parts

A mixture of a part of the solvent with a dye and various additives and a part of the solvent with a thickener added to the solvent are mixed and then stirred for 1 hour to reduce shear viscosity. Ink A was obtained.
The ink had a pH of 2.9 and a viscosity of 20 ° C. measured using an EMD type rotational viscometer (manufactured by Toki Sangyo Co., Ltd., RE-80R, using a standard rotor). The shear thinning index was 0.95.

Preparation of shear-thinning color-changing ink B Blue dye 4.0 parts [manufactured by Clariant GmbH, C.I. I. Acid Blue 93)
Phosphate ester surfactant (lubricant) 0.5 part [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Prisurf A212E]
Coal acid (preservative) 0.1 part Lactic acid (pH adjuster) 2.0 part Polyvinyl alcohol (thickener) 5.0 part [Nippon Gosei Co., Ltd., trade name: Gohsenol GL-30]
Glycerin 15.0 parts Water (ion exchange water) 73.4 parts

A mixture of a part of the solvent with a dye and various additives and a part of the solvent with a thickener added to the solvent are mixed and then stirred for 1 hour to reduce shear viscosity. Ink B was obtained.
The pH of the ink is 2.5, and the viscosity is 20 ° C. using an EMD type rotational viscometer (manufactured by Toki Sangyo Co., Ltd., RE-80R, using a standard rotor). The shear thinning index was 0.97.

Preparation of shear thinning color-changing ink C Green dye 2.0 parts [Hodogaya Chemical Co., Ltd., C.I. I. Basic green 1]
Phosphate ester surfactant (lubricant) 0.5 part [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Prisurf A212E]
Coal acid (preservative) 0.1 part p-toluenesulfonic acid (pH adjuster) 0.5 part Polyvinyl alcohol (thickener) 3.0 part [manufactured by Nippon Synthetic Chemical Co., Ltd., trade name: Gohsenol NL-05]
Ethylene glycol 9.0 parts Water (ion exchange water) 84.9 parts

A mixture of a part of the solvent with a dye and various additives and a part of the solvent with a thickener added to the solvent are mixed and then stirred for 1 hour to reduce shear viscosity. Ink C was obtained.
The pH of the ink is 2.6, and the viscosity is 20 ° C. using an EMD type rotational viscometer (manufactured by Toki Sangyo Co., Ltd., RE-80R, using a standard rotor). The shear thinning index was 0.95.

Preparation of non-shear thinning color-change ink D Pink dye 2.0 parts [Hodogaya Chemical Co., Ltd., C.I. I. Basic Red 13]
Phosphate ester surfactant (lubricant) 0.5 part [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Prisurf A212E]
Coal acid (preservative) 0.1 part Citric acid (pH adjuster) 1.0 part Glycerin 15.0 parts Water 81.4 parts

A colorant and various additives were added to the solvent and stirred for 1 hour to obtain a non-shear thinning color changing ink D.
The pH of the ink was 2.7, and the viscosity was 20 ° C. using a B-type rotational viscometer (manufactured by Tokyo Keiki Co., Ltd., using BL, BL adapter). As a result, it was 2.0 mPa · s. there were.

Preparation of Ink Backflow Preventing Body a Into 85 parts of polybutene as a base oil, 15 parts of fatty acid amide was added as a thickener, and then kneaded with 3 rolls to obtain an ink backflow preventing body a.
The ink backflow preventer was measured at 20 ° C. using a rheometer (Paar Physica, DSR4000, 2 ° cone plate (diameter 25 mm)). As a result, tan δ exceeded 1 at 100 rad / s. Met.

Example 1
Preparation of discoloring ballpoint pen refill (see Fig. 1)
A ballpoint pen tip 2 that rotatably holds a 0.5 mm ball 3 at the tip, a connection member 5 to which the ballpoint tip 2 is secured at the front, and a connection member 5 that is secured to the tip opening; and The polypropylene ink storage tube 6 (inner diameter 3.8 mm) in which the discolorable ink (A) 61 and the ink backflow preventer (a) 62 are stored, and the rear end opening of the ink storage tube 6 are fixed. Thus, a discolorable ballpoint pen refill 1 comprising a tail plug 7 and a resilient member 4 (coil spring) which is housed inside the ballpoint pen tip 2 and the connecting member 5 and urges the ball 3 forward is obtained. The resilient member 4 includes a rod portion 41 and a rear coil portion 42, and a bulging portion 43 having an outer diameter larger than the outer diameter of the coil is formed at the rear end portion of the coil portion 42.
The bulging portion 43 is locked to a locking protrusion 51 on the inner surface of the connection member 5.
The tail plug 7 is provided with ventilation holes 71 in the front and rear.

Production of color-changing ball-point pen The above-mentioned color-changing ball-point pen refill was incorporated into a shaft cylinder, and a cap was fitted to produce a color-changing ball-point pen (not shown).
When writing on the paper surface using the color-changing ballpoint pen, a dark red handwriting was obtained with a light writing feeling, and in addition, ink discharge at the beginning of writing was good.

Example 2
A color-changing ballpoint pen was obtained in the same manner as in Example 1 except that the shear-thinning color-changing ink B was used.
When writing on the paper surface using the color-changing ballpoint pen, a dark blue handwriting was obtained with a light writing feeling, and the ink was discharged well at the beginning of writing.

Example 3
A color-changing ballpoint pen was obtained in the same manner as in Example 1 except that the shear-thinning color-changing ink C was used.
When writing on the paper surface using the color-changing ballpoint pen, a dark green handwriting was obtained with a light writing feeling, and the ink at the beginning of writing was good.

Example 4
A color-changing ballpoint pen was obtained by the same method as in Example 1 except that the shear-thinning color-changing ink D was used.
When writing on the paper surface using the color-changing ballpoint pen, a dark pink handwriting was obtained with a light writing feeling, and the ink discharge at the beginning of writing was good.

Preparation of color changing solution Sodium sulfite (reducing agent) 10.0 parts Potassium carbonate 1.0 part Phosphate ester surfactant 0.2 part [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Prisurf AL]
Carboxylic acid (preservative) 0.1 part Glycerin 10.0 part Water (ion-exchanged water) 78.7 parts A reducing agent and various additives were added to the solvent and stirred to obtain a color changing liquid.

Preparation of discoloration applicator The discoloration liquid was impregnated into a fiber sizing ink occlusion body in which a polyester sliver was coated with a synthetic resin film, and accommodated in a shaft cylinder. An applicator for discoloration in the form of a marking pen was obtained.
The discoloring applicator is provided with a detachable cap.

Preparation of color change applicator The color change liquid is directly accommodated in a shaft cylinder, and a ballpoint pen tip holding a ball having a diameter of 0.7 mm is attached to the tip of the shaft cylinder via a comb groove-shaped ink flow rate adjusting member. An applicator for discoloration in the form of a ballpoint pen was obtained.
The discoloring applicator is provided with a detachable cap.

Preparation of a double-head discoloration ballpoint pen A discoloration ballpoint pen refill containing the ink prepared in Example 2 above is accommodated in one of the shaft cylinders, and a discoloration applicator in the form of a marking pen is fitted to the other to provide double-head discoloration. I got a ballpoint pen.
When writing on the paper surface using the ballpoint pen, a blue handwriting was obtained, and when the color changing solution was applied from above the handwriting using a color changing applicator, the handwriting was decolored.
The double-headed color-changing ballpoint pen is excellent in portability and convenience because writing and erasing can be performed with a single writing instrument.

Preparation of Writing Instrument Set A writing instrument set was obtained by combining the discoloring ballpoint pen containing the ink prepared in Example 1 and a discoloring applicator in the form of a marking pen.
When writing on the paper surface using the ballpoint pen, a red handwriting was obtained, and when the color changing liquid was applied from the handwriting using a color changing applicator, the handwriting was decolored.

Preparation of writing instrument set A writing instrument set was obtained by combining each of the color-changing ballpoint pens and the ballpoint pen-shaped color-changing applicator.
When writing on the paper surface using each of the ballpoint pens, colorful red, blue, green and pink handwriting was obtained. When the color changing solution was applied from above the handwriting using a color changing applicator, each handwriting was decolored.

Preparation of shear thinning viscosity-changing ink E Blue dye 4.0 parts [manufactured by Clariant GmbH, C.I. I. Acid Blue 93)
Phosphate ester surfactant (lubricant) 0.5 part [Daiichi Kogyo Seiyaku Co., Ltd., trade name: Prisurf 212E]
Coal acid (preservative) 0.1 part Citric acid (pH adjuster) 0.5 part Xanthan gum (thickener) 0.45 part Glycerin 15.0 parts Water 79.45 parts

A mixture of a part of the solvent with a dye and various additives and a part of the solvent with a thickener added thereto are mixed together, and then stirred for 1 hour to reduce shear viscosity. Ink E was obtained.
The ink had a pH of 3.0 and a viscosity of 20 ° C. measured using an EMD type rotational viscometer (manufactured by Toki Sangyo Co., Ltd., RE-80R, using a standard rotor). It was 716.8 mPa · s at 1 mPa · s and 1 rpm, and the shear thinning index was 0.26.

Comparative Example 1
A color-changing ballpoint pen was obtained in the same manner as in Example 1 except that the shear-thinning color-changing ink E was used.
When writing on the paper surface using the color-changing ballpoint pen, a blue handwriting was obtained, but it had a heavy writing feeling, and the ink at the beginning of writing was slightly poor, and the desired handwriting could not be obtained.
In addition, the handwriting is difficult to dry, and rubbing with a finger contaminates the blank area on the paper surface and impairs the appearance.

The following ink backflow prevention bodies (b, c, d) were prepared, and filled with ballpoint refills in the combinations shown in the following table together with the inks (A to E) and the ink backflow prevention bodies a to obtain a color-changing ballpoint pen. .
Preparation of Ink Backflow Preventer b In 95 parts of dimethyl silicone oil as a base oil, 5 parts of hydrophobic silica as a thickener was added and then kneaded with three rolls to obtain an ink backflow preventer b.
The ink backflow preventive was measured at 20 ° C. using a rheometer (Paar Physica, DSR4000, 2 ° cone plate (diameter 25 mm)). As a result, tan δ exceeded 1 at 200 rad / s. Met.

Preparation of ink backflow prevention body c In 95 parts of polybutene as a base oil, 5 parts of fatty acid amide as a thickener was added, and then kneaded with 3 rolls to obtain an ink backflow prevention body c.
The ink backflow preventer was measured at 20 ° C. using a rheometer (Paar Physica, DSR4000, 2 ° cone plate (diameter 25 mm)). As a result, tan δ exceeded 1 at 10 rad / s. Met.

Preparation of ink backflow prevention body d In 90 parts of polybutene as a base oil, 5 parts of fatty acid amide and 5 parts of hydrophobic silica are added as a thickening agent, and then kneaded with three rolls to form an ink backflow prevention body d. Got.
The ink backflow preventive was measured at 20 ° C. using a rheometer (Paar Physica, DSR4000, 2 ° cone plate (diameter 25 mm)). As a result, tan δ exceeded 1 at 500 rad / s. Met.

The following tests were conducted using each of the color-changing ballpoint pens obtained by the above combination.
Follow-up test The operation of continuously writing 10 circles each having a diameter of 2 cm using each color-changeable ballpoint pen in 17 lines was repeated 17 times per minute, and the state of the handwriting was observed visually.
Impact resistance test Each color-changing ball-point pen was dropped on a cedar board having a thickness of 120 mm from a height of 120 cm with the ink backflow prevention body facing downward, and this was repeated three times to check for the presence of backflow.
The following table shows the results of each test.

The evaluation of each test result in the table is as follows.
Follow-up test ○: Ink discharge is good from the beginning, and good handwriting is formed to the end.
X: Slightly poor in initial ink appearance and faint in handwriting.
Impact resistance test ○: No change is observed.
X: The interface between the ink and the ink backflow preventive body is greatly increased, and the ink flows back.

Application example 1
Production of intrusion-type discoloration ballpoint pen (see Fig. 2)
A clip 83 that can be locked to a pocket of clothes is formed on the outer surface of the rear portion of the shaft cylinder 81, and the discoloration ballpoint pen refill 1 shown in FIG. 1 is urged backward by a spring 82 (coil spring) inside the shaft cylinder 81. When the rear end portion (knock operation portion) of the shaft cylinder 81 is knocked forward, the ball-point pen tip 2 protrudes from the tip hole of the shaft cylinder 81 to the outside.
The retractable discoloration ballpoint pen 8 has a viscoelastic ink backflow preventer according to the present invention, although a large impact is applied to the ballpoint pen refill 1 when the ballpoint pen tip 2 is retracted into the shaft cylinder 81 by the rearward bias of the spring 82. The impact is absorbed by 62, and the backflow of the ink 61 is sufficiently prevented.

Application example 2
Manufacture of an in / out type discoloration ballpoint pen (see Fig. 3)
A clip 83 that can be locked in a pocket of clothes is formed on the outer surface of the front portion of the shaft tube 81 (the outer surface of the gripping portion of the shaft tube), and the color-changing ballpoint pen refill 1 shown in FIG. The ball-point pen tip 2 protrudes to the outside from the tip hole of the shaft tube 81 by being housed in a rear biased state by the (coil spring) and knocking the rear end portion (knock operation portion) of the shaft tube 81 forward.
In particular, the retractable color-changing ballpoint pen 8 of this application example includes the clip 83 on the outer surface of the front portion of the shaft cylinder 81, and is thus locked in the pocket of the clothes in a state where the pen tip is upward. Thereby, in the pocket locking state, ink leakage from the tip of the ball-point pen tip 2 is prevented, and soiling of clothes can be avoided.
The retractable discoloration ballpoint pen 8 has a viscoelastic ink backflow preventer according to the present invention, although a large impact is applied to the ballpoint pen refill 1 when the ballpoint pen tip 2 is retracted into the shaft cylinder 81 by the rearward bias of the spring 82. The impact is absorbed by 62, and the backflow of the ink 61 is sufficiently prevented.

It is a longitudinal cross-sectional view of the color-change ball-point pen refill used for this invention. FIG. 2 is a cross-sectional explanatory diagram of a retractable color-changing ballpoint pen in which the color-changing ballpoint pen refill of FIG. 1 is inserted into a shaft cylinder. FIG. 7 is another vertical cross-sectional explanatory diagram of a retractable color-changing ballpoint pen in which the color-changing ballpoint pen refill of FIG. 1 is inserted into a shaft cylinder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color change ball-point pen refill 2 Ball-point pen tip 3 Ball 4 Repelling member 41 Rod part 42 Coil part 43 Swelling part 5 Connection member 51 Locking protrusion 6 Ink storage pipe 61 Color change ink 62 Ink backflow prevention body 7 Tail plug 71 Ventilation hole 8 Retractable color changing pen 81 Shaft cylinder 82 Spring 83 Clip

Claims (16)

  A ballpoint pen in which an ink containing tube including a ballpoint pen tip holding a ball at the tip is directly filled with ink and an ink backflow preventer, and the ink is discolored or decolored by water and a reducing agent. The viscosity at 100 rpm in an E-type rotational viscometer composed of at least 20 ° C. and a dye is in the range of 3 to 160 mPa · s, and the shear thinning index is in the range of 0.6 to 0.99. A color-changing ink or a non-shear thinning color-changing ink having a viscosity in the range of 1 to 50 mPa · s, and a pH-changing ballpoint pen having a pH in the range of 1 to 6.   The discolorable ball-point pen according to claim 1, wherein the discolorable ink contains polyvinyl alcohol or polyvinylpyrrolidone.   The discolorable ballpoint pen according to claim 1 or 2, wherein the pH of the ink is in the range of 1 to 4.   The color-changing ball-point pen according to claim 1, wherein the ink containing tube also serves as a shaft cylinder.   The discolorable ballpoint pen according to claim 1, wherein the ink containing tube is accommodated in a shaft tube.   6. The color-changing ballpoint pen according to claim 5, wherein the ballpoint pen tip can be projected and retracted from the tip hole of the shaft tube.   The color-changing ball-point pen according to claim 6, wherein a clip is formed on the outer surface of the front portion of the shaft tube.   The ink backflow preventer comprises at least a base oil and a thickener, and a point (ω) where tan δ in viscoelasticity measurement exceeds 1 is in a range of 20 rad / s ≦ ω ≦ 450 rad / s. Discoloring ballpoint pen.   A ballistic member that bounces the back end of the ball forward is arranged. When not writing, the ball is pressed against the inner edge of the tip to bring it into close contact, and when writing, the ball can be retracted by writing pressure to allow ink to flow out. The discolorable ballpoint pen according to claim 1, wherein the discolorable ballpoint pen is constituted.   The color-changing ball-point pen according to any one of claims 1 to 9, further comprising a color-changing applicator containing a color-changing liquid at a rear end portion of the ball-point pen.   The color-changing ball-point pen according to claim 10, wherein the color-changing applicator is a marking pen having a marking pen tip at a tip portion or a ball pen having a ball-point pen tip holding a ball at the tip portion. The said discoloration applicator is a ball-point pen, The diameter (A) of the ball | bowl provided in the said ball-point pen, and the diameter (B) of the ball | bowl provided in the discoloration ball-point pen satisfy | fill following formula (1). Discoloring ballpoint pen.
A ≧ B (1)   A writing instrument set comprising the color-changing ball-point pen according to any one of claims 1 to 12 and a color-changing applicator containing a color-changing liquid.   The writing instrument set according to claim 13, wherein the discoloring applicator is a marking pen having a marking pen tip at a tip portion or a ball pen having a ball pen tip having a ball held at the tip portion. The said discoloration applicator is a ball-point pen, The diameter (A) of the ball | bowl provided in the said ball-point pen, and the diameter (B) of the ball | bowl provided in the color-change ball-point pen satisfy | fill following formula (2). Writing instrument set.
A ≧ B (2)   The writing instrument set according to any one of claims 13 to 15, comprising a plurality of color-changing ballpoint pens having different color tones and a color-changing applicator.

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