JP5053006B2 - 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, it is related with the water-based ink composition for ball-point pens which was excellent in lubrication performance and was provided with high writing performance, and the ball-point pen which incorporated the same.

Conventionally, in a ballpoint pen incorporating a water-based ink having poor lubricity compared to oil-based ink, wear of the ball seat due to rotation of the ball is likely to occur. As a result, the ink flow path in the ballpoint pen tip may be deformed, resulting in defective ink discharge or leakage. For this reason, there has been a problem that writing feeling is impaired or writing failure is caused.
Therefore, in order to solve the above problem, an attempt is made to improve the lubricity of water-based ink and reduce the wear of the ball seat by adding potassium oleate soap or amino acid type betaine as a lubricant to the ink composition. (For example, refer to Patent Documents 1 and 2).
JP-A 61-16974 JP 10-67961 A

However, the amino acid-type betaine has a low lubricating effect, and potassium oleate soap needs to be added in a large amount in order to exert a sufficient effect. It caused problems such as precipitation inside. In addition, when it added in the range which does not produce the said precipitation, abrasion of a ball seat could not fully be suppressed but the writing distance became short.
In particular, when the ball diameter is as small as 0.4 mm or less, the number of rotations of the ball with respect to the writing distance increases, and therefore wear is more likely to occur. Therefore, a higher lubrication effect is required.

  The present invention suppresses the wear of the ball seat due to the rotation of the ball, thereby ensuring a good ink discharge property over a long distance writing, and does not impair the excellent writing feeling. An object and a ballpoint pen incorporating the object are provided.

The water-based ink composition for ballpoint pens of the present invention is required to contain at least a colorant, water, and a thioamide represented by the following general formula (1).
RC (= S) NH ₂ (1)
[Wherein R represents any of _{CH 3,} C 2 _{H 5.} ]
Furthermore, it is required that the thioamide is added in the range of 0.01 to 10% by weight in the total amount of the ink composition, and the pH of the ink is in the range of 7 to 12.
Furthermore, it is a requirement that the ballpoint pen contains any of the above-described water-based ink compositions for ballpoint pens, and that the ballpoint pen includes a ball of 0.4 mm or less at the writing tip.

  According to the present invention, wear of the ball seat due to the rotation of the ball can be suppressed, and high lubrication performance can be maintained during writing, so that a smooth writing feeling can be maintained over a long distance without causing blurring or line skipping in the handwriting. A water-based ink composition for a ballpoint pen and a ballpoint pen incorporating the ink composition can be provided.

  In the water-based ink composition for ballpoint pens, the present invention can suppress wear of the ball seat due to the rotation of the ball by containing the thioamides represented by the above general formula.

  As the thioamides, thioacetamide and thiopropionamide are applied. These compounds are thought to reduce the contact resistance between the ball and the seat during writing by the thioamide structure portion forming a film on the surface of the ball or chip (ball seat) in the ink.

The thioamides can be added in an amount of 0.01 to 10% by weight, preferably 0.05 to 7% by weight, based on the total amount of the ink composition.
If it is less than 0.01% by weight, it is difficult to obtain the desired effect, and even if added over 10% by weight, no improvement in wear-inhibiting effect is observed, so no further addition is required.

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

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

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

Examples of the pigment include inorganic pigments such as carbon black and ultramarine blue, and organic pigments such as copper phthalocyanine blue and benzidine yellow, as well as water-dispersed pigments that are finely and stably dispersed in an aqueous medium in advance using a surfactant or the like. Products are used, for example
C. I. Pigment Blue 15: 3B [Product Name: S.P. S. Blue GLL, pigment content 22%, manufactured by Sanyo Dye Co., Ltd.]
C. I. Pigment Red 146 [Product Name: S.P. S. Pink FBL, pigment content 21.5%, manufactured by Sanyo Color Co., Ltd.]
C. I. Pigment Yellow 81 [Product name: TC Yellow FG, pigment content about 30%, manufactured by Dainichi Seika Kogyo Co., Ltd.]
C. 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 synthetic resin in which various fluorescent dyes are formed into a solid solution in a resin matrix can be used.
Other examples include pearl pigments, gold and silver metallic pigments, luminous pigments, white pigments such as titanium dioxide used in correction pens, metal powders such as aluminum, fragrances, and fragrance capsule pigments.

The colorant can be used singly or in combination of two or more, and is used in the range of 0.01 to 15% by weight, preferably 0.1 to 10% 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, as necessary, inorganic salts such as sodium carbonate, sodium phosphate, sodium acetate, pH adjusters such as organic basic compounds such as water-soluble amine compounds, rust preventives such as benzotriazole, tolyltriazole, 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) pyridine Preservatives or antifungal agents such as urea, nonionic surfactants, sorbitol, mannitol, sucrose, glucose, reduced starch hydrolyzate, wetting agents such as sodium pyrophosphate, antifoaming agents, ink permeability A fluorine-based surfactant or a nonionic surfactant to be improved may be used.
Furthermore, polyalkylene glycol fatty acid ester, ethylene oxide addition type cationic surfactant, phosphate ester surfactant, thiocarbamate, dimethyldithiocarbamate, N-acylamino acid, N-acylmethyltaurine, metal soap, etc. These lubricants can also be used in combination.

A shear thinning agent can also be added to the ink composition.
As the shear thinning agent, a water-soluble or dispersible substance is effective, and xanthan gum, welan gum, and succinoglycan whose constituent monosaccharide is an organic acid-modified heteropolysaccharide of glucose and galactose (average molecular weight) About 1,000 to 8 million), guar gum, locust bean gum and derivatives thereof, hydroxyethyl cellulose, alginic acid alkyl esters, polymers having a molecular weight of 100,000 to 150,000 based on alkyl esters of methacrylic acid, glucomannan, agar and carrageenan Carbohydrates having gelling ability extracted from seaweed such as benzylidene sorbitol and benzylidene xylitol or their derivatives, crosslinkable acrylic acid polymers, inorganic fine particles, nonionic surfactants having an HLB value of 8 to 12, dialkylsulfosuccinic acid Metal salts and nets Can be exemplified a salt, further, be added in combination in the ink composition N- alkyl-2-pyrrolidone and anionic surfactant can have stable shear thinning.

The ink composition is applied by adjusting the pH to a neutral to alkaline range of 7 to 12, preferably a neutral to weak alkaline range of pH 7 to 11.
By adjusting the pH, thioamides act stably in the ink, so that seat wear can be efficiently suppressed.

Furthermore, an ink backflow preventer (liquid stopper) can be disposed at the rear end 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 oligomer, silicone oil, and refined mineral oil. If desired, silica, aluminum silicate, swellable mica, fatty acid amide and the like can be added to the medium. Moreover, a resin molding is mentioned as a solid ink backflow prevention body. The liquid and solid ink backflow preventers can be used in combination.

The structure of the tip end (tip) of the ballpoint pen that is filled with the water-based ink composition for ballpoint pens is effective in a conventional general-purpose mechanism, and a ball holder in which the vicinity of the tip end of a metal pipe is pressed and deformed inward from the outer surface. A chip formed by holding a ball in the holding part, or a chip formed by holding a ball in a ball holding part formed by cutting a metal material with a drill or the like, or cutting a metal pipe or metal material A ball or the like held by a chip formed by processing is urged forward by a spring body can be applied.
Moreover, the said ball | bowl can apply the general purpose thing which consists of a cemented carbide alloy, stainless steel, a ruby, a ceramic, etc., 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 shaft cylinder that accommodates the water-based ink composition in terms of low ink evaporation and productivity.
In addition to directly connecting the tip to the shaft tube, the shaft tube and the chip may be connected via a connecting member.
When the ink composition is low in viscosity, the ink composition accommodated in the shaft cylinder includes a method of mounting an ink retaining member at the front of the shaft cylinder and storing the ink composition directly in the shaft cylinder, Examples of the method include impregnating the ink composition into a material body or a fiber processed body.
In addition, the said shaft cylinder may accommodate the said refill in a shaft cylinder as a form of the refill for ball-point pens.

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 configured as a ballpoint pen refill, in which the refill is stored in a shaft tube, or the shaft tube with a tip attached to a tip is used as an ink storage body in the shaft tube. You may fill ink directly.

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) manufactured by Sumitomo Chemical Co., Ltd., trade name: Acid Blue PG, C.I. I. Acid blue 90
(2) Hodogaya Chemical Co., Ltd., trade name: Eosin, C.I. I. Acid red 87
(3) Hodogaya Chemical Co., Ltd., trade name: Phloxine, C.I. I. Acid red 92
(4) Product name: KELZAN, manufactured by Sanki Co., Ltd.
(5) Product name: FZ2163, manufactured by Toray Dow Corning
(6) Product name: FR-14 (solid content 21%), manufactured by Kao Corporation
(7) Product name: Anhitoru 86B (solid content 26%), manufactured by Kao Corporation

Preparation of Ink Each component was prepared by adding each component to water, stirring at 400 rpm for 1 hour with a disper at 25 ° C., and filtering.

Preparation of Ink Backflow Preventer Body In 85 parts of polybutene as a base oil, 15 parts of fatty acid amide as a thickener was added, and then kneaded with three rolls to obtain an ink backflow preventer body.

Preparation of Ballpoint Pen The same amount of the ink composition of the above-mentioned Examples and Comparative Examples was filled in a ballpoint pen refill fitted with one end of a polypropylene pipe with a stainless steel chip holding a cemented carbide ball having a diameter of 0.25 mm. Then, after the ink backflow preventer was disposed at the rear end, the ballpoint pen refill was incorporated into a shaft tube to prepare a sample ballpoint pen.

The following tests were conducted using the sample ballpoint pen.
Writing test The writing distance when the sample ball-point pen confirmed to be writable was continuously written on a JIS P3201 writing paper A with a spiral circle was measured with an automatic writing tester.
Furthermore, the amount of wear (the amount of ball sinking in a state where the pen tip is upward) with respect to the initial state of the ball seat portion after writing was measured.
The tester was used under the conditions of a writing load of 100 g, a writing angle of 70 °, and a writing speed of 4 m / min. Moreover, the value of a test result is an average value of what was tested 5 each.
The results of the test are shown in the following table.

Claims (5)

A water-based ink composition for ballpoint pens containing at least a colorant, water, and a thioamide represented by the following general formula (1).
RC (= S) NH ₂ (1)
[Wherein R represents any of _{CH 3,} C 2 _{H 5.} ]   The aqueous ink composition for ballpoint pens according to claim 1, wherein the thioamide is added in an amount of 0.01 to 10% by weight based on the total amount of the ink composition.   The aqueous ink composition for ballpoint pens according to claim 1 or 2, wherein the pH of the ink is in the range of 7-12.   The ball-point pen which incorporated the water-based ink composition for ball-point pens in any one of the said Claim 1 thru | or 3.   The ball-point pen according to claim 4, wherein the ball-point pen has a ball of 0.4 mm or less at a writing tip.