JP5431011B2 - Water-based ink composition for ballpoint pen and ballpoint pen incorporating the same - Google Patents

Description

  The present invention relates to a water-based ink composition for ballpoint pens. Furthermore, the present invention relates to a water-based ink composition for ballpoint pens imparted with shear thinning viscosity and a ballpoint pen incorporating the same.

  Conventionally, aqueous ink compositions for ballpoint pens containing shear thinning agents such as xanthan gum and diutane gum have been disclosed as inks having shear thinning among aqueous inks (see, for example, Patent Documents 1 and 2).

  This type of ink has a high viscosity when it is left to stand without shear stress, and is stably held in the mechanism. When writing, the ink in the vicinity of the ball is low due to the high shear force of the ball rotating at high speed. As a result, the ink is discharged from the gap between the ball and the ball container and transferred onto the paper surface. Since the ink transferred onto the paper surface is released from the shearing force, it becomes a highly viscous state and does not cause handwriting blur, which is a defect of the conventional water-based ink composition. In addition, ink leakage does not occur due to the above-mentioned shear thinning and there is no need for a flow rate adjusting member (temporary ink retaining member such as a comb-like member) for adjusting the ink flow rate. There is also an advantage that a writing instrument is obtained.

  However, since the xanthan gum and the diutan gum are inferior in stability over time in a water-based ink medium, the ink viscosity tends to increase with time. For this reason, in the writing over time, the ink ejection from the pen tip becomes unstable, and there is a case in which handwriting blurring occurs, and further, writing cannot be performed.

JP 59-74175 JP 2005-68363 A

  INDUSTRIAL APPLICABILITY The present invention is applicable to a writing instrument having a simple structure, and uses a water-based ink composition for ballpoint pens that can maintain excellent writing performance for a long period of time by using a shear thinning agent that can exhibit long-term stable performance, and the built-in ink composition A ballpoint pen is provided.

The water-based ink composition for ballpoint pens of the present invention is required to contain a colorant, water and sclerotium gum.
Furthermore, it is a requirement that the sclerotium gum is added in the range of 0.1 to 2.0% by weight in the total amount of the ink composition.
Furthermore, a ballpoint pen incorporating the water-based ink composition for ballpoint pens is a requirement.

  According to the present invention, it is possible to express shear thinning with a stable viscosity over a long period of time, so that it can be applied to a writing instrument having a simple structure and can maintain excellent writing performance for a long period of time without causing handwriting defects such as handwriting scraping. A composition and a ballpoint pen incorporating the composition can be provided.

The sclerotium gum is a yeast polysaccharide obtained by fermentation of the fungus Screotiium rolfsii using glucose as a substrate, and the β-1,6-glucoside bond is on the side of the β-1,3-glucoside bond trimolecular skeleton. It is a polymeric polysaccharide having a structure in the chain.
As a commercial item, the brand name: AMIGEL made from Alba Muller International is mentioned.
The sclerotium gum can be added in an amount of 0.1 to 2% by weight, preferably 0.1 to 1% by weight, based on the total amount of the ink composition.
If it is less than 0.1% by weight, it is difficult to impart sufficient shear thinning to the entire ink, and even if it is added in excess of 2% by weight, no more than a certain level of shear thinning is observed. The above addition is not required.

As the colorant, all dyes and pigments that can be dissolved or dispersed in an aqueous medium can be used, and specific examples thereof will be exemplified below.
As the dye, an acid dye, a basic dye, a direct dye, or the like can be used.
Examples of the acid dye include New Coxin (CI. 16255), Tartrazine (CI. 19140), Acid Blue Black 10B (CI. 20470), Guinea Green (CI. 42085), Brilliant Blue FCF. (CI.42090), Acid Violet 6B (C.I.42640), Soluble Blue (C.I.42755), Naphthalene Green (C.I.44025), Eosin (C.I.45380), Phloxin (C.I. 45410), erythrosine (C.I. 45430), nigrosine (C.I. 50420), acid flavin (C.I. 56205) and the like are used.

  Examples of basic dyes include chrysoidine (C.I. 11270), methyl violet FN (C.I. 42535), crystal violet (C.I. 42555), malachite green (C.I. 42000), Victoria Blue FB ( CI 44045), rhodamine B (C.I. 45170), acridine orange NS (C.I. 46005), methylene blue B (C.I. 52015) and the like are used.

  As direct dyes, Congo Red (C.I. 22120), Direct Sky Blue 5B (C.I. 24400), Violet BB (C.I. 27905), Direct Deep Black EX (C.I. 30235), Kaya Las Black G Conch (C.I. 35225), Direct Fast Black G (C.I. 35255), Phthalocyanine Blue (C.I. 74180) and the like are used.

Examples of the pigment include inorganic pigments such as carbon black and ultramarine blue, and organic pigments such as copper phthalocyanine blue and benzidine yellow, as well as water-dispersed pigments that are finely and stably dispersed in an aqueous medium in advance using a surfactant or the like. For example, C.I. I. Pigment Blue 15: 3B [Product Name: S.P. S. Blue GLL, pigment content 22%, manufactured by Sanyo Color Co., Ltd.], C.I. I. Pigment Red 146 [Product Name: S.P. S. Pink FBL, pigment content 21.5%, manufactured by Sanyo Dye Co., Ltd.], C.I. I. Pigment Yellow 81 [Product name: TC Yellow FG, pigment content about 30%, manufactured by Dainichi Seika Kogyo Co., Ltd.], C.I. I. Pigment Red220 / 166 [Product name: TC Red FG, pigment content: about 35%, manufactured by Dainichi Seika Kogyo Co., Ltd.].
As the fluorescent pigment, a fluorescent pigment in the form of fine particles of 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, large hysteresis characteristics (ΔH _B = 8 to 50 ° C.) described in JP- _B -4-17154, JP-A-7-179777, JP-A-7-33997, JP-A-8-39936, and the like. ), That is, when the shape of the curve plotting the change in the color density due to the temperature change is lowering the temperature from the lower temperature side than the color changing temperature range, as opposed to increasing the temperature from the lower temperature side. Reversible heat with color memory in a specific temperature range when the color changes in a low temperature range below the complete color development temperature or in a high temperature range above the complete color erase temperature. A heat-decolorable microcapsule pigment in which the color-changing composition is encapsulated in microcapsules is also applicable.
Specifically, as the reversible thermochromic composition having color memory, a complete color development temperature can be obtained only in a freezing room, a cold district, etc., that is, −50 to 0 ° C., preferably −40 to − 5 ° C., more preferably −30 to −10 ° C., and complete decoloring temperature obtained from a frictional heat generated by a friction body, a heating body such as a hair dryer, that is, 50 to 95 ° C., preferably 50 to 90 ° C. More preferably, by specifying the range of 60 to 80 ° C. and specifying the ΔH value of 40 to 100 ° C., it is possible to effectively function to maintain the color exhibited in the normal state (daily life temperature range).

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.

Further, if necessary, a conventional general-purpose water-soluble organic solvent compatible with water can be used. Specifically, ethanol, propanol, butanol, glycerin, sorbitol, triethanolamine, diethanolamine, monoethanolamine, ethylene glycol, diethylene glycol, thiodiethylene glycol, polyethylene glycol, propylene glycol, butylene glycol, ethylene glycol monomethyl ether, ethylene glycol mono Examples include ethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, sulfolane, 2-pyrrolidone, and N-methyl-2-pyrrolidone.
In addition, the said water-soluble organic solvent can be used 1 type or in combination of 2 or more types, and is used in 2 to 60 weight%, Preferably it is 5 to 35 weight%.

  Furthermore, a water-soluble resin can be added in order to impart adhesion and viscosity to the paper surface. Examples of the water-soluble resin include alkyd resins, acrylic resins, styrene maleic acid copolymers, cellulose derivatives, polyvinyl pyrrolidone, polyvinyl alcohol, and dextrin. The water-soluble resin can be used alone or in combination of two or more, and is used in the range of 1 to 30% by weight in the ink composition.

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

The water-based ink composition is filled in a ballpoint pen with a ballpoint tip attached to the writing tip.
The structure and shape of the ballpoint pen itself are not particularly limited, and a conventional one can be applied. For example, the ballpoint pen has an ink containing tube filled with an ink composition, and the ink containing tube has a ball. An example is a ballpoint pen that communicates with a tip attached to the tip and further has an ink backflow prevention body in close contact with the ink end face.

The ballpoint pen tip will be described in more detail. A tip formed by holding a ball in a ball holding portion obtained by pressing and deforming the vicinity of the tip of a metal pipe inward from the outer surface, or a metal material is cut by a drill or the like A chip formed by holding the ball in the ball holding part formed by the above, or a ball held in a chip formed by cutting a metal pipe or metal material, and the like that is urged forward by a spring body, etc. Can be applied.
Moreover, a cemented carbide, stainless steel, a ruby, a ceramic, etc. can be applied to the said ball | bowl, and the thing of the range of diameter 0.1mm-2.0mm is used suitably.

For example, a molded body made of a thermoplastic resin such as polyethylene, polypropylene, or polyethylene terephthalate is preferably used as the ink storage tube for storing the water-based ink composition in terms of low ink evaporation and productivity. Further, by using a transparent, colored transparent, or translucent molded body as the ink containing tube, the ink color, the remaining amount of ink, and the like can be confirmed.
In addition to directly connecting the chip to the ink storage tube, the ink storage tube and the chip may be connected via a connecting member.
The ink storage tube may be a refill type in which the refill is stored in a shaft tube, or the shaft tube itself having a tip attached to a tip is used as an ink container, and ink is directly applied to the shaft tube. It may be filled.

Further, an ink backflow preventer (liquid stopper) is filled in the rear end portion of the ink composition filled in the ink containing tube.
As the ink backflow preventer, either liquid or solid can be used, and examples of the liquid ink backflow preventer include non-volatile media such as polybutene, α-olefin co-oligomer, silicone oil, and refined mineral oil. If desired, silica, aluminum silicate, swellable mica, fatty acid amide and the like can be added to the medium. Moreover, a resin molding is mentioned as a solid ink backflow prevention body. The liquid and solid ink backflow preventers can be used in combination.

The ballpoint pen may be either a cap-type or a retractable type, and the retractable ballpoint pen is placed in the shaft cylinder (outer shaft) with the writing tip provided on the ballpoint pen refill exposed to the outside air. Any structure can be used as long as it is housed and the writing tip protrudes from the opening of the shaft cylinder by the operation of the retracting mechanism.
Examples of the operation method of the retracting mechanism include a knock type, a rotary type, and a slide type.
The knock type has a knock portion on the rear end portion of the shaft tube and the side surface of the shaft tube, and by pressing the knock portion, the writing tip portion of the ballpoint pen refill is projected and retracted from the front end opening portion of the shaft tube, or on the shaft tube. The structure which makes the writing tip part of a ball-point pen refill appear and disappear from the axial cylinder front-end opening part by pressing the provided clip part can be illustrated.
The rotary type has a rotating part at the rear part of the shaft cylinder, and can be exemplified by a configuration in which the writing tip part of the ballpoint pen refill is projected and retracted from the front end part of the shaft cylinder by turning the rotating part.
The slide type has a slide part on the side surface of the shaft cylinder, and the sliding tip of the writing point of the ballpoint pen refill is projected and retracted from the front end opening of the shaft cylinder by operating the slide, or the clip part provided on the shaft cylinder is slid. By doing so, it is possible to exemplify a configuration in which the writing tip of the ballpoint pen refill is projected and retracted from the opening at the front end of the shaft cylinder.
The retractable ballpoint pen may be a composite retractable ballpoint pen (refill exchange type) in which a plurality of ballpoint pen refills are accommodated in a shaft cylinder.

Examples will be described below, but the present invention is not limited to these examples.
The composition of the water-based ink for ballpoint pens of Examples and Comparative Examples is shown in the following table. In addition, the numerical value of a composition in a table | surface shows a weight part.

The contents of the raw materials in the table will be described along the note numbers.
(1) Made by Orient Chemical Industry Co., Ltd., trade name: Water Black 100L, solid content 20%
(2) Sanyo Dye Co., Ltd., trade name: Sundai Super Color Blue GLL, solid content 25%
(3) LANXESS Co., Ltd., trade name: Special Yellow NS-L, solid content 20%
(4) 1,2-Benz-6- (N-ethyl-N-isoamylamino) fluorane, 1,3-dimethyl-6-diethylaminofluorane, 1,1-bis (4'-hydroxyphenyl) 2-ethyl A microcapsule pigment encapsulating a reversible thermochromic composition having color memory consisting of hexane and 4-methylbenzyl palmitate (colored red at -2 ° C and decolored at 48 ° C, average particle size: 2. 5 μm, solid content 27.3%)
(5) Product name: FZ2163, manufactured by Toray Dow Corning Co., Ltd.
(6) Product name: Prisurf A208B, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.
(7) Daiichi Kogyo Seiyaku Co., Ltd., trade name: Prisurf A207H

Preparation of Ink Components other than gums were added to water, mixed and stirred, then gums were added, stirred at 400 rpm with a disper at 20 ° C. for 1 hour, and filtered to prepare each ink.

Preparation of Ink Backflow Preventing Body After adding 1.5 parts of fatty acid amide as a thickener to 98.5 parts of polybutene as a base oil, the mixture was kneaded with three rolls to obtain an ink backflow preventing body.

Preparation of Ballpoint Pen The ink compositions of the above examples and comparative examples were filled into a ballpoint pen refill fitted with one end of a polypropylene pipe with a stainless steel tip holding a cemented carbide ball having a diameter of 0.3 mm. After the ink backflow preventive body was disposed on, the ballpoint pen refill was incorporated into a shaft cylinder (cap type) to prepare a sample ballpoint pen.
The following tests were conducted using the ink composition and the sample ballpoint pen.

Ink Viscosity Test 5 g of each prepared ink was transferred to a sample bottle and left in a 70 ° C. environment for 60 days. Thereafter, the ink viscosity was measured at room temperature (20 ° C.). The ink viscosity was measured at 1 rpm and 10 rpm with a RE-80R viscometer manufactured by TOKI. For comparison, the viscosity (initial value) immediately after ink preparation was also measured under the same conditions.

Written test Each sample ball-point pen that was confirmed to be writable was left in a 70 ° C environment for 60 days in a horizontal position, and then handwritten on the old JIS P3201 writing paper A at room temperature. 5 circles were continuously written. The writing (first three circles) at that time and the subsequent handwriting state were visually confirmed.
The results of the test are shown in the following table.

The evaluation of the test results is as follows.
Written test Writeability ○: No blurring occurs.
Δ: Scratch was initially generated, but it recovered with a circle within the third.
X: It did not recover at the third circle or less, and scum was generated on the fourth and subsequent circles.
Written state ○: A good handwriting was shown.
X: Scratch and line jump were seen in the handwriting.

Claims (3)

  A water-based ink composition for ballpoint pens containing a colorant, water, and sclerotium gum.   The water-based ink composition for ballpoint pens according to claim 1, wherein the sclerotium gum is added in an amount of 0.1 to 2.0% 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.