JPS648673B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an ink composition for a water-based ballpoint pen. Water-based ballpoint pen inks have excellent cap-off properties (the ability to write for long periods of time with the ballpoint pen cap removed);
The pen must have an appropriate viscosity or fluidity to enable smooth writing with a uniform thickness in correspondence with a ball of a given diameter, the ink will not run out even at high writing speeds, and the pen will not run out after writing. It is necessary to have properties such as not leaving any ink scum, having excellent storage stability over a long period of time, and not being corrosive to the metal parts of ballpoint pens. However, these properties include mutually contradictory elements; for example, known inks with excellent cap-off properties tend to have high viscosity and tend to run out. Therefore, there is much room for improvement in the existing inks, and the emergence of new inks is desired. As a result of various experiments and research while keeping the above-mentioned current situation in mind, the present inventor has found that when a specific amount of xanthan gum is added to a water-based ballpoint pen ink, an ink having all of the above-mentioned properties can be obtained. I found out. That is, the present invention relates to an aqueous ballpoint pen ink composition characterized by containing 0.20 to 0.45% by weight of xanthan gum. The xanthan gum used in the present invention has a molecular weight of
It is a water-soluble polymeric polysaccharide with a weight of about 5 million to 10 million.
The amount of xanthan gum used is 0.20 in the ink composition.
~0.45% by weight. The amount of xanthan gum is 0.20
When the amount is less than 0.45% by weight, it is difficult to write smoothly, while when it is more than 0.45% by weight, the viscosity of the ink increases and the outflow of the ink from the pen tip tends to be inhibited. The content of xanthan gum is more preferably 0.30 to 0.40% by weight in the ink composition. The components in the ink composition for a water-based ballpoint pen of the present invention other than kiquintan gum are not particularly different from the components in known inks for water-based ballpoint pens. That is, the ink composition of the present invention contains, for example, 5 to 40% by weight of an aqueous medium consisting of water or water and alcohol, glycol ether, etc., 0.1 to 15% by weight of a water-soluble or water-dispersible colorant, a surfactant, and a preservative. , 0 to 10% by weight of additives such as PH regulators and rust preventives, and 0.20 to 0.45% by weight of xanthan gum. Examples of components other than xanthan gum are as follows. Aqueous medium component 1 Monohydric alcohol: Alcohol miscible with water such as ethanol and isopropyl alcohol. 2 Dihydric alcohols) ethylene glycol,) diethylene glycol,) triethylene glycol,)
1,3-propanediol,) propylene glycol,) 1,3-butylene glycol,
)1,4-butanediol,)2,3-butylene glycol,)neopentyl glycol,)hexylene glycol,)thiodiglycol, etc. 3 Trihydric or higher alcohols) glycerin,) trimethylolethane,) trimethylolpropane,) 3-methylpentane-1,3,5-triol,)
diglycerin,) sorbit etc. 4 Others...pyrrolidone, N-methyl-2-pyrrolidone, dimethylformamide, etc. glycol ether) ethylene glycol monomethyl ether,
) ethylene glycol monoethyl ether,
) ethylene glycol monobutyl ether,
) diethylene glycol monomethyl ether,
) diethylene glycol monoethyl ether,
) diethylene glycol monobutyl ether, etc. Colorant 1 Pigment) Titanium oxide,) Carbon black,
) Carmine 6B, ) CIPigment Red112,
)CIPigmentBlue 15,)CIPigment
Green7 et al. 2 Acid dye (indicated by CI number) ) Acid Red87, ) Acid Red92, )
Acid Yellow28,) Acid Blue9,) Acid
Violet49,) Acid Blue7,) Acid
Orange56,) Acid Black2,) Acid
Red18 etc. 3 Direct dye (indicated by CI number) ) Direct Black19, ) Direct Black38,
) Direct Black154, ) Direct Orange6,
) Direct Yellow44,) Direct Yellow87,
) Direct Blue71, etc. Additive 1 Nonionic and anionic surfactants Polyethylene glycol oleyl ether, polyethylene glycol nonyl phenyl ether, polyethylene glycol polypropylene glycol ether, 2,4,7,9
- Nonionic surfactants such as ethylene oxide adducts of tetramethyl-5-decyl-4,7-diol. Naphthalene sulfonic acid formalin condensate,
Anionic surfactants such as dialkyl sulfosuccinates or their soda salts. 2 Preservatives) Potassium sorbate,) Sodium benzoate,) Sodium pentachlorophenol,) Sodium dehydroacetate, etc. 3 PH regulators) Sodium hydroxide,) Sodium carbonate,) Triethanolamine, etc. 4 Rust preventive agent) Benzotriazole,) Tolyltriazole,) Dicyclohexylammonium nitrate, etc. As the aqueous medium component, polyhydric alcohols and glycol ethers are more preferred. The amount of aqueous medium components such as alcohol and glycol ether among the above components is 5 to 40% of the ink composition.
It is preferable to set it as a proportion occupying % by weight. If this amount exceeds 40% by weight, the viscosity increases,
In addition, it tends to cause bleeding during writing, while if it is less than 5% by weight, the storage stability and cap-off properties of the ink composition will be reduced. The ink composition of the present invention containing xanthan gum as an essential component is not limited to the above composition, and compositions containing components other than the above are also included within the scope of the present invention. The ink composition of the present invention is produced, for example, as follows. Gradually add xanthan gum to water being stirred at room temperature until completely dissolved, then add aqueous medium components such as polyhydric alcohols and/or glycol ethers, colorants, and other additives to dissolve or dissolve them. Distribute evenly. The ink composition of the present invention has excellent storage stability and exhibits appropriate viscosity and fluidity over a long period of time. Therefore, as shown in FIG. 1, the ink composition has a ballpoint pen body 1, a backflow prevention part 3, an ink conductor 5, a pen tip part 7, and a ball 9, and an intermediate hollow part 11 as an ink storage part. It is extremely useful as an ink for "ink-free" type water-based ballpoint pens. Examples 1 to 9 and Comparative Examples 1 to 2 Ink compositions were prepared using the raw materials shown in Tables 1 and 2. In Tables 1 and 2, "→" indicates "same as on the left".

【table】

【table】

[Table] In Tables 1 and 2, the meanings of the notes are as follows. 1 Trade name: “Kelzan”, manufactured by Sansho Co., Ltd. 2 Trade name “Eosin”, manufactured by Hodogaya Chemical Industry Co., Ltd. 3 Trade name: “Acidophloxin PB”, manufactured by Hodogaya Chemical Industry Co., Ltd. 4 Trade name “Tartrazine”, Hodogaya Chemical Industry
Manufactured by Co., Ltd. 5 Measured using an ELD type viscometer. 6 Trade name: “Water Blue #9”, manufactured by Orient Chemical Industry Co., Ltd. 7 Trade name “Water Black 100-L” (dye solid content, approximately 20% by weight), Orient Chemical Industry Co., Ltd.
Made. Next, each of the inks obtained above was placed in a ballpoint pen of the type shown in FIG. 1, and various tests were conducted. The results are shown in Table 8. The specifications of the ballpoint pen used are as follows. Ball 9...Steel ball with a diameter of 0.4 mm. Pen tip 7...Made of polyacetal, diameter 1.5mm,
It has an ink outlet hole with a length of 7 mm. Ink conductor 5: Polyester fiber bundle processed with resin, diameter 3 mm, length 5 mm, porosity 60%
It is. Ink tank 11...Made of polypropylene, inner diameter 3
mm, the length of the tank part is 80mm.

【table】

[Table] Examples 10 to 12 Ink compositions were prepared using the raw materials shown in Table 4. In Table 4, "→" indicates "same as on the left".

【table】

[Table] When the inks obtained in Examples 10 to 12 were subjected to the tests shown in Table 3, they were rated ○ in all of the cap-off properties, ink flow properties, shorthand properties, and ink scum. Furthermore, the dryness of the handwriting using the ballpoint pen (measuring the time until it is dry to the touch after writing the letter "V" on high-quality paper)
As a result of investigation, the time was 35 seconds in Example 10, 20 seconds in Example 11, and 15 seconds in Example 12, but when dialkyl sulfosuccinate or (and) its soda salt was not used and water was 62.6% by weight. The drying time was 80 seconds or more.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a water-based ballpoint pen suitable for using the ink composition of the present invention. DESCRIPTION OF SYMBOLS 1... Ballpoint pen body, 3... Backflow prevention part, 5... Ink conductor, 7... Pen tip part, 9... Ball, 11... Ink storage part.

Claims (1)

[Claims] 1. An aqueous ballpoint pen ink composition containing 0.20 to 0.45% by weight of xanthan gum.