JP2662882B2 - Pigment ink for ballpoint pens - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a pigment ink for ballpoint pens, and more particularly, to a pigment ink for ballpoint pens that combines the characteristics of an oil-based ink and a water-based ink, and that pigment dispersion is stable over time. The present invention relates to a pigment ink for a ball-point pen with a small decrease in property.

(Prior Art) The inventors of the present invention have the following features of oil-based ballpoint pen ink: the ability to check the remaining amount of ink, the ability to write smoothly without bleeding, and the feature point of aqueous ballpoint pen ink. As a pigment ink for ballpoint pens, which has both high quality handwriting and no broken lines or
A ballpoint pen pigment ink comprising at least a pigment, water and a water-soluble organic solvent and having an ink viscosity in the range of 50 to 2000 cps (25 ° C.), characterized in that the viscosity modifier is a water-soluble polymer. Pigment ink was proposed earlier.

(Problem to be Solved by the Invention) The present invention relates to the improvement of the pigment ink for a ballpoint pen according to the above-mentioned proposal of the present invention.

That is, the pigment ink for a ballpoint pen using a water-soluble polymer as a viscosity modifier has a tendency that the dispersion stability of the pigment decreases over time, aggregation of the pigment particles occurs, and the apparent pigment particles tend to be large, Due to the sedimentation of the pigment, the handwriting becomes thinner when the pen tip is stored upward, the handwriting becomes darker when the pen tip is stored downward, or it becomes extremely impossible to write The potential was inherent.

(Means for Solving the Problems) Accordingly, the present inventors have made an object of the present invention to prevent a decrease in the dispersion stability of the pigment.

That is, the present invention relates to a ballpoint pen pigment containing at least a pigment, water, a water-soluble polysaccharide, and a polyglycerin fatty acid ester represented by the following general formula, and having a viscosity of 50 to 2000 cps (25 ° C.). It is based on ink.

Hereinafter, the present invention will be described in detail.

The pigment is used as a colorant and is not particularly limited. Specifically, azo pigments, phthalocyanine pigments, nitrone pigments, nitro pigments, basic dye pigments, acid dye pigments , Vat dye pigments, organic pigments such as mordant dye pigments and natural dye pigments, and loess, barium yellow, dark blue, cadmium red, barium sulfate, titanium oxide, red iron oxide, iron black, aluminum hydroxide, calcium carbonate, And inorganic pigments such as carbon black. These can be used alone or as a mixture, and 3 to 20% by weight based on the total amount of the pigment ink for a ballpoint pen.
Is preferred.

The water-soluble organic solvent is used for various qualities as a pigment ink for ballpoint pens, that is, for prevention of ink drying at a pen tip, prevention of ink freezing at low temperatures, and the like.
Specifically, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol,
Polyethylene glycol, 1,3-butylene glycol,
Crychols such as thiodiethylene glycol and glycerin, ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, 2-pyrrolidone, N
-Methyl-2-pyrrolidone, triethanolamine and the like are used alone or in combination, and the amount used is preferably 50% by weight or less based on the total amount of the pigment ink for ballpoint pens.

As the water-soluble polysaccharide as a viscosity modifier, a cellulosic thickener such as carboxymethylcellulose and hydroxypropylcellulose, and a plant thickener such as guar gum and gum arabic can be used. These can be mixed and used.

The polyglycerol fatty acid ester represented by the above general formula, which is the gist of the present invention, is used to prevent aggregation of pigment particles, and specifically, lauric acid, myristic acid, stearic acid of decaglycerin, Esters such as isostearic acid, oleic acid and linolenic acid,
Hexaglycerin lauric acid, myristynic acid, stearic acid, isostearic acid, oleic acid, esters such as linolenic acid can be used alone or in combination of two or more,
The amount used is 0.1 to 10, preferably 0.3 to 5 parts by weight per 10 parts by weight of the pigment.

In addition, the pigment ink for ballpoint pens of the present invention has a viscosity of
It is an essential requirement that the temperature be 25 to 2000 cps at 25 ° C. If the ink viscosity is less than 50 cps, ink leakage from the pen tip is apt to occur, and if it exceeds 2000 cps, ink is not discharged well from the pen tip, and blurring or the like is likely to occur in handwriting.

In addition to the above essential components, conventionally known surfactants, dispersants, preservatives, fungicides, lubricants and the like may be appropriately selected.

In order to obtain the present pigment ink for ballpoint pens, it is easily obtained by dispersing and mixing the above components using a disperser.If necessary, coarse particles such as pigments are removed by a method such as filtration or centrifugation. You can also.

(Action) The reason why the pigment ink for a ballpoint pen according to the present invention does not cause aggregation of the pigment particles over time is speculated as follows.

That is, the pigment particles are charged with the same sign at the time of dispersion, so that in the ink, an electric repulsion acts between the particles and the dispersed state can be stably maintained with time. The water-soluble polymer to be added as a viscosity modifier to the dispersion generally has a hydrophilic group and has no cross-linking structure, and thus exhibits polarizability or ionicity, and thus has an effect on the electric repulsion in the pigment dispersion. And disperses over time, but when used together with the polyglycerin aliphatic ester represented by the above general formula, the polyglycerol moiety in the polyglycerin aliphatic ester has a strong polarizability and no polarity The aliphatic alkyl group appropriately enters the pigment and the water-soluble polymer to reduce the mutual influence, so that the dispersion state can be stably maintained over time.

(Examples) Hereinafter, the present invention will be described in more detail with reference to Examples.
“Parts” in the examples and comparative examples indicates “parts by weight”.

Example 1 Carbon black (inorganic pigment) 10.0 parts SMA Resin 1440 (styrene-maleic acid copolymer ammonium salt aqueous solution, solid content 27 wt%, dispersant, manufactured by ARCO Chemical Co., Ltd.) 5.0 parts Glycerin 15.0 parts CMC-dial # 2000 (carboxy) Methylcellulose, manufactured by Dial Chemical Industry Co., Ltd. 2.0 parts Decagulin 1-L (Decaglyceryl monolaurate,
2.0 parts, water 66.0 parts The above components were mixed and dispersed in a ball mill for 24 hours, and then filtered through a 1 μm filter to obtain a pigment ink for a black ballpoint pen having a viscosity of 800 cps.

Example 2 Brillia Fast Scarlet (azo red organic pigment, CI No. 12315, manufactured by Sumika Color Co., Ltd.) 10.0 parts Joncryl 61J (styrene-acrylic acid copolymer ammonium salt aqueous solution, solid content 30 wt%, dispersant 10.0 parts Ethylene glycol 20.0 parts PVP-K90 (polyvinyl pyridone, manufactured by BASF) 5.0 parts Hexaglin 1-L (hexaglyceryl monolaurate, Nikko Chemicals Co., Ltd.) 3.0 parts Water 52.0 parts The components were mixed and subjected to a dispersion treatment with a ball mill for 24 hours, followed by filtration with a 1 μm filter to obtain a pigment ink for a red ball-point pen having a viscosity of 200 cps.

Example 3 Copper phthalocyanine blue (phthalocyanine blue organic pigment, CI No. 74160) 10.0 parts Joncryl 62 (styrene-methylstyrene-acrylic acid copolymer ammonium salt aqueous solution, solid content 34% by weight, dispersant, Johnson Co., Ltd.) 8.0 parts Glycerin 13.0 parts HPC [H] (hydroxypropylcellulose, Nippon Soda Co., Ltd.) 0.5 parts Decaglin 1-O (Decaglyceryl monooleate,
3.0 parts, water 65.5 parts The above components were mixed and dispersed in a ball mill for 24 hours, followed by filtration with a 1 μm filter to obtain a pigment ink for a blue ballpoint pen having a viscosity of 350 cps.

Example 4 Carbon black 10.0 parts Joncryl J62 10.0 parts Glycerin 15.0 parts CMC-Daicel # 1180 (carboxymethylcellulose, manufactured by Dial Chemical Industry Co., Ltd.) 3.0 parts Hexagulin 1-M (hexaglyceryl monomyristate, Nikko Chemicals Co., Ltd.) 2.0 parts Water 60.0 parts The above components were mixed and dispersed in a ball mill for 24 hours, and then filtered through a 1 μm filter to obtain a black ballpoint pen pigment ink having a viscosity of 600 cps.

Comparative Example 1 In the same manner as in Example 1 except that in place of decagrin 1-L, Nikkor MYS-25 (polyoxyethylene (25) monostearate, manufactured by Nikko Chemicals Co., Ltd.) was used. And a pigment ink for a black ballpoint pen having a viscosity of 800 cps was obtained.

Comparative Example 2 Example 2 was repeated except that in place of hexagulin 1-L, Nikkor TO-10 (polyoxyethylene (20) sorbitan monooleate, manufactured by Nikko Chemicals Co., Ltd.) was used. In the same manner, a pigment ink for a red ball-point pen having a viscosity of 200 cps was obtained.

Comparative Example 3 In Example 1 above, CMC-Daicel # 2000 was
Parts and 67.9 parts of water, to obtain a pigment ink for a black ballpoint pen having a viscosity of 40 cps.

Comparative Example 4 In Example 1 described above, CMC-Daicel # 2000 was replaced with 2.7
Parts, and 65.3 parts of water, to obtain a pigment ink for a black ballpoint pen having a viscosity of 2200 cps.

(Effects of the Invention) The pigment inks for ballpoint pens obtained in Examples 1 to 4 and Comparative Examples 1 and 2 are placed in a glass bottle, sealed, and allowed to stand in a constant temperature room at 50 ° C, before and after standing. The size of the pigment particles was measured. Table 1 shows the results.

Further, the pigment ink for ballpoint pens obtained in Examples 1 to 4 and Comparative Examples 1 to 4 was filled into a transparent resin cylinder having an inner diameter of 3 mm, and a stainless steel ballpoint pen tip for water-based ink having a tip set with a 0.5 mmφ carbide ball was used. The test pieces were combined to form a test ballpoint pen, and a quality test was performed. Table 2 shows the results.

As described in detail above, the pigment ink for a ballpoint pen according to the present invention has a small decrease in the dispersion stability of the pigment over time, and also has the features of the pigment ink for an aqueous ballpoint pen and the pigment ink for an oil-based ballpoint pen. Pigment ink for ballpoint pens.

The ballpoint pen tip of a ballpoint pen is usually made of resin or metal (stainless steel) for water-based ink, and metal (stainless steel or brass) for oil-based ink. Such a ballpoint pen pigment ink can be used for any of the above-mentioned resin and metal products.
That is, it goes without saying that the material of the ball chip that can be used is not limited.

Claims (1)

(57) [Claims] 1. A pigment ink for a ballpoint pen containing at least a pigment, water, a water-soluble polysaccharide, and a polyglycerol fatty acid ester represented by the following general formula and having a viscosity in the range of 50 to 2000 cps (25 ° C.). .