JP3121571B2 - Oil-based ballpoint pen ink - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an oil-based ink for a ballpoint pen. More specifically, the present invention relates to a water-insoluble, polar ink for a ballpoint pen that does not use water.

[0002]

2. Description of the Related Art Conventionally, by imparting a shear thinning viscosity to ink, the viscosity in an ink container is made relatively high to enhance ink retention, and by rotating a ball, the ink viscosity at the time of writing is reduced to give a brush feeling. An aqueous ink composition or an aqueous ballpoint pen containing the ink composition, which improves handwriting, is disclosed in, for example, JP-A-7-173426,
US Pat. No. 4,671,691; EP 870204; Japanese Patent Publication No. 64-8673;
According to the publication of 256700 or the like, or an oil-based ink composition or an oil-based ballpoint pen containing the ink composition is disclosed in, for example, JP-A-63-114695, JP-A-6-313143, and JP-A-7-196972. This is disclosed in Japanese Patent Publication No. However, none of these are fully satisfactory as ballpoint pen inks. This is because the water-based ink uses water as a main solvent, and the ink supply power to the writing tip of a ballpoint pen or the writing paper surface is not sufficient. Ballpoint pen has a shear rate of 4
Generally, if the viscosity at 00 sec ^-1 is not more than about 100 mPas, it is not possible to write well, and if the viscosity in the ink container is not more than about 3000 mPas, it will not flow well. For this reason, there is a problem that there is always a risk of ink leakage from the leading end of the writing head or the rear end of the ink storage cylinder as the ink retaining property.
In addition, oil-based inks generally use a solvent having a high ink supply power to the writing tip of a ball-point pen or the writing paper surface as a main solvent, so that even high-viscosity inks can be sufficiently written, and in order to prevent dripping of the ink, 5,000 to 5,000. 2
The penetration was prevented with a high viscosity of about 0000 mPas. The ink viscosity range that can be set in this way is relatively wide, but the drawback is that the penetrating effect of the handwriting occurs due to the high ink supply power to the writing paper surface, and the pen can be written with low writing pressure and can be written smoothly. Shear rate 40 for realizing the feeling
The viscosity at 0 sec ^-1 is 200 to 3000 mPas.
When set to, there is a problem that the penetrating phenomenon of handwriting cannot be sufficiently prevented.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to realize a low-pressure writing and a smooth writing feeling, high ink retention in a pen body, no ink leakage, and penetrating of handwriting on paper. An object of the present invention is to provide an ink for a ball-point pen that does not cause a problem.

[0004]

Means for Solving the Problems The present invention provides: (1) a water-insoluble polar solvent comprising an aromatic alcohol and / or an aliphatic glycol phenyl ether, a polyhydric alcohol, and (B) a coloring material. , (C) a crosslinked acrylic acid polymer, (D) a triethanolamine and a water-insoluble organic amine, and a shear rate of 400 sec ^-1.
The oil for a ball-point pen having a viscosity of 200 to 3000 mPas and a shear thinning index of 0.30 to 0.85. 2. (A) The water-insoluble polar solvent of the component is composed of 20% to 50% by weight of an aromatic alcohol and / or an aliphatic glycol phenyl ether and 20% to 50% by weight of a polyhydric alcohol with respect to the total amount of the ink. The ink for a ball-point pen according to the above item. 3. Color material is 3% to 30% by weight based on the total amount of ink
3. The ink for an oil-based ballpoint pen according to paragraph 1 or 2. 4. 4. The oil-based ballpoint pen ink according to any one of items 1 to 3, wherein the coloring material is an oil-soluble dye or a water-soluble dye soluble in a polyhydric alcohol. 5. 5. The oil-based ballpoint pen ink according to any one of items 1 to 4, wherein the crosslinked acrylic acid polymer is blended in an amount of 0.3% by weight to 2.0% by weight based on the whole ink. 6. 0.5% of water-insoluble organic amine to the whole ink
An oil-based ballpoint pen according to any one of Items 1 to 5, wherein the oil-based ball-point pen is compounded in an amount of 0.5% to 5.0% by weight and triethanolamine in an amount of 0.5% to 4.0% by weight based on the whole ink. For ink. 7. 7. The oil-based ballpoint pen ink according to any one of items 1 to 6, further comprising a spinnability imparting agent. 8. Item 8. The oil-based ballpoint pen ink according to item 7, wherein the spinnability imparting agent is blended in an amount of 0.1% by weight to 1.5% by weight. 9. 9. The oil-based ink for a ballpoint pen according to any one of items 1 to 8, wherein a rust preventive lubricant soluble in polyhydric alcohol and a bactericide soluble in polyhydric alcohol are blended. 10. A blend of 0.2% to 3.0% by weight of a rust preventive lubricant soluble in polyhydric alcohol and 0.1% to 1.0% by weight of a bactericide soluble in polyhydric alcohol, 9 The ink for a ball-point pen according to the above item. 11. Item 1 to 1 in which one or more fatty acids selected from lauric acid, oleic acid, ricinoleic acid, stearic acid and soybean oil fatty acids are blended as lubricity improvers.
Item 10. The ink for an oil-based ballpoint pen according to any one of Items 0 to 0. 12. Item 12. The oil-based ballpoint pen ink according to item 11, wherein a fatty acid is added in an amount of 0.5% by weight to 5.0% by weight. 13. 13. The oil-based ballpoint pen ink according to any one of items 1 to 12, wherein a water-insoluble thickener is blended in an amount of 0.1% by weight to 10% by weight. About.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water-insoluble polar solvent obtained by mixing a water-insoluble polar solvent composed of an aromatic alcohol and / or an aliphatic glycol phenyl ether and a polyhydric alcohol, a coloring material, and a crosslinked acrylic. Viscosity at a shear rate of 400 sec ^-1 consisting of an acid polymer is 200 to
At 3000 mPas, the shear thinning index is 0.30 to 0.8
5 is an ink for a ballpoint pen. When a water-insoluble polar solvent is used as the ink solvent, the ink supply power to the writing tip and the writing paper surface is overwhelmingly higher than when water is the main solvent, and good writing is possible even with a relatively high viscosity. Becomes In addition, since the ink of the ballpoint pen tip has high wettability, the fixing power in the tip portion of the writing is good, and the ink retention is dramatically improved. Further, it has an excellent effect of preventing evaporation of the ink as compared with the case where water is used as the main solvent. As the water-insoluble polar solvent, aromatic alcohol and / or
Alternatively, an aliphatic glycol phenyl ether and a polyhydric alcohol are used. Examples of the aromatic alcohol include benzyl alcohol, phenylethyl alcohol, methylphenylcarbinol, and phthalyl alcohol. Examples of the aliphatic glycol phenyl ether include ethylene glycol monophenyl ether, propylene glycol phenyl ether, propylene glycol, and diphenyl ether. One or more water-insoluble polar solvents selected from these are used.

When the amount of the water-insoluble polar solvent to be mixed is low, the ink viscosity must be set low if the ink supply power to the writing tip and the writing paper surface is small, causing a problem in ink retention and causing handwriting on the paper surface. From the viewpoint of preventing strike-through of the ink composition, the amount is preferably 20 to 50% by weight based on the total amount of the ink composition. As a solvent in the ink, polyhydric alcohol is also used as an essential component, but the paper surface generally has a hydrophilic group, and if a highly hydrophilic polyhydric alcohol is contained as a solvent, strikethrough of handwriting can be reduced. It is. Further, the crosslinked acrylic acid polymer used as a shear thinning agent is generally a water-swellable type, and can contain a polyhydric alcohol in a solvent, so that it can be uniformly swelled in the ink and can be set to a suitable ink viscosity. It is.

The polyhydric alcohol is one or more selected from ethylene glycol, propylene glycol, glycerin, diethylene glycol, thiodiglycol, polyglycerin, polyethylene glycol, methyl cellosolve, butyl cellosolve, methyl carbitol and ethyl carbitol. Polyhydric alcohols are used.
The compounding amount of the polyhydric alcohol prevents penetrating of the handwriting, uniformly swells and disperses the crosslinked acrylic acid polymer which is a shear-thinning agent in the ink, and also prints the ink on the writing tip and the writing paper surface. In order to eliminate the shortage of the supply power and to set the ink viscosity sufficient to guarantee the ink retention, the amount is preferably 20% by weight to 50% by weight based on the total amount of the ink composition.

As a coloring material, a water-soluble dye, an oil-soluble dye or a pigment can be used without limitation according to the intended purpose. However, for a capless ballpoint pen having no cap, a water-soluble dye having resolubility is used. Dyes and oil-soluble dyes are preferred. As water-soluble dyes, Direct Black 19, Direct Black 154, Direct Blue 3, Acid Blue 90, Acid Red 94, Acid Red 9
2. Acid orange 56. As oil-soluble dyes, trade names: Spiron Black GMH, Spiron Blue C-RH, Spiron Violet C-RH, (all manufactured by Hodogaya Chemical Co., Ltd.), Bali Fast Red 13
20, Balifast Blue 1621 and Balifast 1701 (all manufactured by Orient Chemical Co., Ltd.). As the pigment, trade name: Specia
l Black 350 (made by Degussa), Printex
75 (made by Degussa), FASTOGEN BLUE E
P-7 (manufactured by Dainippon Ink and Chemicals, Inc.), Pali
oogen Blue L6480 (manufactured by BASF), SY
MULER RED 3111 (manufactured by Dainippon Ink and Chemicals, Inc.), Irgazin DPP Red BO
(Made by Ciba Geigy). Although the ink of the present invention does not contain water, the water-soluble dye can be used since the water-soluble dye is dissolved in the polyhydric alcohol. Water-soluble dyes have many kinds of colors, so that they also have a complementary color effect of oil-soluble dyes.
The mixing amount of the coloring material is 3 parts with respect to the total amount of the ink composition in terms of the density of the handwriting, the dry-up resistance or the ink stability.
~ 30% by weight is preferred.

[0009] The effect of imparting shear thinning to the ink is provided by the crosslinked acrylic acid polymer. The writing taste or handwriting at the time of writing greatly depends on the ball rotation at the tip of the writing. At this time, if the ball rotates smoothly without resistance, good writing quality and good writing lines can be obtained. Of course, it may not be good due to the structural problem of the writing tip, but it has been found that the problem is largely due to the ink viscosity. In other words, if the ink viscosity is too high during writing, resistance to ball rotation occurs, and the ball does not rotate well. This is why an oil-based ballpoint pen generally has a very heavy brush feel, and is likely to cause line cracks and blurring in the handwriting. In addition, as is well known, the ink also acts as a lubricant against the frictional resistance generated between the ball and the ball holder material at the writing tip, and the effect of the lubricant as it has a certain degree of viscosity is Are better.

The inventor of the present invention has made intensive studies on the above-mentioned ink viscosity and lubricating action, and as a result, found that the shear rate was 400 sec.
It has been found that by setting the viscosity at ^-1 to 200 to 3000 mPas, it is possible to write smoothly with low writing pressure and to obtain good handwriting. However, with such an ink viscosity, it is not possible to completely prevent ink leakage from the tip of the writing head or the rear of the ink container. The present invention is
At the time of writing, by imparting a shear thinning property to the ink, the desired viscosity of the ink is set to 200 to
The viscosity was 3,000 mPas, and the viscosity was sufficient to prevent ink leakage in the ink container that was not subjected to shearing. When the viscosity at a shear rate of 400 sec ^-1 is 200 to 3000 mPas, if water is used as the main solvent as described above, a water-insoluble polar solvent is used because of lack of ink supply power to the writing tip of a ballpoint pen or writing paper. Although used independently, penetrating of handwriting occurs on the writing paper. In the present invention, strike-through can be alleviated by using a polyhydric alcohol having a strong hydrophilicity as a solvent in combination. It has been found that by setting the viscosity index to 0.85 or less, strikethrough of handwriting can be completely prevented. On the other hand, if it is not more than 0.30, there is a possibility that a problem of poor writing may occur due to lack of fluidity of the ink,
The shear thinning index is preferably 0.30 to 0.85. The amount of the crosslinked acrylic acid polymer as a shear-thinning agent can be adjusted by setting the shear-thinning index or by uniformly swelling the shear-thinning agent in the ink to obtain a stable ink. 0.3 to 2.0% by weight based on the total amount of the composition is suitable.

When a crosslinked acrylic acid polymer is used as a shear thinning agent, the organic amine does not dissolve in the polyhydric alcohol but the triethanolamine dissolves, so that the crosslinked acrylic acid polymer is neutralized with triethanolamine. It swells in polyhydric alcohol. The organic amine does not dissolve in the polyhydric alcohol but dissolves in the aromatic alcohol or the aliphatic glycol phenol ether, so that the crosslinked acrylic acid polymer is neutralized and swollen in these solvents. In order to swell and disperse the crosslinked acrylic acid polymer imparting shear thinning properties in a water-insoluble polar solvent comprising an aromatic alcohol and / or an aliphatic glycol phenol ether and a polyhydric alcohol, triethanolamine is used. It is necessary to use a water-insoluble organic amine in combination. As the water-insoluble organic amine, polyoxyethylene alkylamine, cetylamine, oleylamine and the like are appropriately used. The blending amount needs to be adjusted depending on the blending amount of the crosslinked acrylic acid polymer, but it is preferable that the total amount of the neutralizing agent is 0.5 to 5.0% by weight based on the total amount of the ink composition.

In the present invention, water is not contained in the ink, but polyhydric alcohol, which is a solvent component in the ink, generally has a strong hygroscopic property, and in an environment with high humidity, moisture is mixed into the ink by moisture absorption. It is preferable to add a rust preventive and a bactericide since the ink may become unstable due to metal corrosion at the tip of the writing and bacteria growing in the ink. It is necessary to dissolve both the rust inhibitor and the germicide in the polyhydric alcohol, and the rust inhibitor is preferably one that also has a role of a swelling agent. As the rust preventive lubricant, one or two or more selected from a phosphate ester surfactant, benzotriazole, and a fatty acid ester are used. If the compounding amount is less than 0.2% by weight based on the total amount of the ink composition, the rust-preventing effect is insufficient, and if the compounding amount exceeds 3% by weight, the cross-linked acrylic acid polymer is not uniform in the ink and a stable ink is obtained. Since it cannot be obtained, the content is preferably set to 0.2 to 3.0% by weight.
As the antibacterial agent, 1,2-benzisothiazoline-3-
ON, sodium benzoate, sodium dehydroacetate and the like are used. If the compounding amount is less than 0.1% by weight based on the total amount of the ink composition, the antibacterial effect is lacking, and if it exceeds 1.0% by weight, the crosslinked acrylic acid polymer is not uniform in the ink, and a stable ink is obtained. Since it cannot be obtained, the content is preferably 0.1 to 1.0% by weight.

In the present invention, a stringiness imparting agent is blended in order to prevent crying at the pen tip and to prevent the writing of the handwriting. In order to improve the writing feel, the ink viscosity at the time of writing is 200 to 3000 mP.
When set to "as", surplus ink that cannot be transferred and penetrated to the paper surface at the pen tip at the time of writing is likely to be generated, which causes crying and dents. In the present invention, the binding property of the ink is increased by adding a spinnability imparting agent, and the generation of excess ink at the pen tip can be prevented. Examples of the spinnability imparting agent include polyvinyl pyrrolidone and polyvinyl alcohol. If the compounding amount is less than 0.1% by weight based on the total amount of the ink composition, the effect is weak.
If the content is more than 0.1% by weight, the setting of the shear thinning index is hindered. Therefore, 0.1 to 1.5% by weight is preferable.

Although the ink viscosity is set to 200 to 3000 mPas and a water-soluble rust-preventive lubricant is blended, a smooth writing feeling can be realized at a low writing pressure, but an oil-based lubricant represented by a fatty acid is further used. By blending, the brush feel and handwriting can be dramatically improved. As the oil-based lubricant, lauric acid, oleic acid, ricinoleic acid, stearic acid, and soybean fatty acid can be used. If the compounding amount is less than 0.5% by weight based on the total amount of the ink composition, the effect is weak, and if it exceeds 5.0% by weight, the aging stability of the ink is lacking. It is suitable. The ink provided with the shear thinning viscosity becomes poor in fluidity as the viscosity increases, and the ink supply from the ink storage cylinder to the writing tip may not be smooth. In this case, by using a thickener in combination, the fluidity of the ink can be maintained and a desired ink viscosity can be obtained. It is desirable that the thickener does not impart shear thinning to maintain ink fluidity. It is desirable to select a water-insoluble thickener so as not to hinder the swelling of the crosslinked acrylic acid polymer in the ink.

As the thickener, ketone resin, phenol resin, amide resin, xylene resin and hydrogenated rosin resin are used. It is necessary to appropriately adjust the viscosity of the ink at rest to a desired viscosity. When the amount is less than 1.0% by weight with respect to the total amount of the ink composition, the effect is small, and when the amount exceeds 10% by weight, the effect of the ink is reduced. 1.0 ~ due to lack of stability
10% by weight is preferred.

[0016]

【Example】

Example 1 Aromatic alcohol 20.0% by weight Polyhydric alcohol 52.4% by weight Colorant 15.0% by weight Crosslinked acrylic acid polymer 0.4% by weight Water-insoluble organic amine 2.0% by weight Triethanolamine 1.5% by weight Water-soluble rust preventive lubricant 1.0% by weight Water-soluble antibacterial agent 0.2% by weight Spinning agent 0.5% by weight Fatty acid 3.0% by weight Water-insoluble thickener 4. 0% by weight The above components excluding the crosslinked acrylic acid polymer were mixed with a magnet stirrer at 60 ° C. for 1 hour to form a uniform microemulsion, and then the crosslinked acrylic acid polymer was homogenized using a homogenizer stirrer. Swell and disperse in
An ink for a ballpoint pen was obtained. The viscosity of the ink for ball-point pens at a shear rate of 400 sec ^-1 was measured using an E-type viscometer (EHD) in an environment of 20 ° C.
It was 50 mPas, and as a result of calculation based on the Power Law formula, the shear thinning index was 0.45. Benzyl alcohol was used as the aromatic alcohol. Ethylene glycol was used as the polyhydric alcohol. As a coloring material, a trade name of an oil-soluble dye; Bali Fast Red 1320 (manufactured by Orient Chemical Industries) was used. As the water-insoluble organic amine, polyoxyethylene alkylamine (trade name; manufactured by Nimeen L-201 Nippon Oil & Fats Co., Ltd.) was used. As the water-soluble rust preventive lubricant, a phosphate ester-based surfactant (trade name; Plysurf A-208S)
(Daiichi Kogyo Seiyaku Co., Ltd.). 1,2-Benzoisothiazolin-3-one (trade name; Proxel XL-2 manufactured by Zeneca Corporation) was used as the water-soluble antibacterial agent. As the spinnability imparting agent, polyvinylpyrrolidone (trade name; manufactured by PVPK-120 ASP Japan Co., Ltd.) was used. Oleic acid was used as a fatty acid as a lubricity improver. As the water-insoluble thickener, a ketone resin (Hilac 110H manufactured by Hitachi Chemical Co., Ltd.) was used. Hibiswako 104 (trade name, manufactured by Wako Pure Chemical Industries, Ltd.) was used as the crosslinked acrylic acid polymer. Table 1 shows the effects of using the ink for a directly-filled ball-point pen without using an ink occluding material.

Examples 2 to 10 Example 1 was repeated except that the ink compositions were as shown in Table 1.
An ink was prepared in the same manner as described above. The effects are shown in Table 1.

[0018]

[Table 1]

(Note) 1. Benzyl alcohol as aromatic alcohol,
Alternatively, ethylene glycol monophenyl ether was used as the aliphatic glycol phenyl ether. 2. Ethylene glycol or glycerin was used as the polyhydric alcohol. 3. As a coloring material, a trade name of an oil-soluble dye; Balifast Red 1320 (manufactured by Orient Chemical Industries), a direct black 154 of a water-soluble dye, or Speci of a pigment
al Black 350 (manufactured by Degussa) was used. 4. Shearing speed of each ballpoint pen ink 400sec
The viscosity and the shear thinning index at ^-1 were obtained in the same manner as in Example 1. 5. Writing taste: particularly good in handwriting evaluation …… ◎ Good thing …… ○ Very poor thing …… ×. 6. Handwriting: In handwriting evaluation on writing paper A (JIS P3201), particularly good ones that do not cause blurring, crying, and line skipping in the handwritings .... ◎ Those that are not particularly noticeable in practical use. Those that frequently generate rashes, crying tears, and skipping lines are marked as ×. 7. Ink leakage; A ball-point pen (without cap) containing ink and weighing 15 g with cap off
The pen was vertically dropped on a cedar board from a height of m with the pen point upward, and ink leakage was confirmed. B. In an environment of 30 ° C. and 80% RH; with the cap off, the pen tip was allowed to stand vertically for 1 day with the pen tip floating with the pen tip floating, and ink leakage from the pen tip was observed. (Note) The diameter of the ink tank was 4 mm in inner diameter, and the backflow prevention member provided at the rear end of the ink was a viscous material having a consistency of 350 and a base oil viscosity of 4 Pas at a temperature of 25 ° C. In the test of B, no ink leakage occurred, and in the test of A, 50
The one that does not cause ink leakage even if it falls over the concave ...
◎ No ink leakage occurred in the test of B, and 40 in the test of A
The ink leaked by dropping not less than 30 times but not more than 50 times ..... ○ In the test of A, the ink leaked by dropping not more than 30 times and B
In the test of, the one that caused ink leakage was evaluated as ×. 8. Penetration of handwriting; writing on writing paper A in an environment of 30 ° C. and 60% RH and leaving it in the same environment for one day,
The writing back was observed. A sample with no bleeding of the ink at all: ◎ A sample with only a slight bleeding ……… A sample with a clear bleeding: × 9. Stability of ink over time: The ink placed in a closed glass container was placed in an environment of 50 ° C. and 0% RH, and evaluated by physical properties of the ink and observation with a microscope. Precipitate is not generated in the ink for more than 3 months, and the change in physical properties is less than 30% compared to the initial time .... ◎ ◎ Precipitate is generated in the ink in 2 to 3 months or compared to the initial time. And those that have changed physical properties by more than 30% ……
を A precipitate which is generated in the ink within one to two months, or whose physical property has changed by 30% or more compared to the initial stage.
Δ: A precipitate was generated in the ink within one month, or a change in physical properties of 30% or more as compared with the initial state was obtained.
X.

Examples 11 to 20 Example 1 was repeated except that the ink compositions were as shown in Table 2.
An ink was prepared in the same manner as described above. The effect is shown in Table 2.

[0021]

[Table 2]

(Note) 1. Oleic acid or stearic acid was used as a fatty acid. 2. Other materials and test methods used are the same as those in Table 1.

Examples 21 to 22 Example 1 was repeated except that the ink compositions were as shown in Table 3.
An ink was prepared in the same manner as described above. The effects are shown in Table 3.

[0024]

[Table 3]

(Note) 1. Ethylene glycol monophenyl ether was used as the aliphatic glycol phenyl ether, or a mixture of benzyl alcohol as the aromatic alcohol and ethylene glycol monophenyl ether as the aliphatic glycol phenyl ether was used. 2. Other materials and test methods used are the same as those in Table 1.

Comparative Examples 1 to 10 Example 1 was repeated except that the ink compositions were as shown in Table 4.
An ink was prepared in the same manner as described above. The effects are shown in Table 4.

[0027]

[Table 4]

(Note) The materials used and the test method are the same as in Table 1.

Evaluation Comparative Example 1 is an example in which a crosslinked acrylic acid polymer and a polyhydric alcohol are not contained in the ink. In this case, the ink viscosity becomes Newtonian viscosity that does not show shear thinning,
It shows the same characteristics as general oil-based ballpoint pens. Even if the emphasis is placed on the writability and the ink viscosity is set to a relatively low viscosity of 4000 mPas, the writing feel is heavy, and the handwriting crying and blurring occurs. In addition, since the ink viscosity does not show shear thinning, ink leakage cannot be completely prevented, and penetrating of handwriting occurs. Supplementally, if the ink viscosity is further reduced, the brush feel can be improved, but the tearing is synergistically deteriorated. In addition, it is clear that ink leakage and penetrating of handwriting are overwhelmingly deteriorated and cannot be put to practical use as ink for ballpoint pens. On the other hand, if the ink viscosity of this form is high enough to prevent ink leakage or penetrating of the handwriting, the ink feel will be overwhelmingly heavy and the handwriting will not be good. This can easily be assumed from Example 1. Comparative Example 2 has a characteristic in which the ink viscosity and the shear thinning index are too high, and the ink viscosity is very close to Newtonian viscosity. Therefore, as in Comparative Example 1, the ink was not practical for a ballpoint pen ink. Comparative Example 3
Is an attempt to solve the problem by making the viscosity of the ink tank relatively low and lowering the viscosity during writing by making the shear thinning index extremely small. A very large amount of acrylic acid polymer had to be added, and the ink was not uniform and stable. Therefore, it could not be evaluated as a ballpoint pen ink. Comparative Example 4 does not include a water-insoluble polar solvent such as an aromatic alcohol or an aliphatic glycol phenyl ether in the ink.
In this case, the ink viscosity was set to a degree sufficient to prevent ink leakage, but the ink discharge amount from the pen tip during writing was poor and could not be evaluated as a ballpoint pen ink. Comparative Examples 5 and 6 are inks containing a coloring material using aromatic alcohols and polyhydric alcohols as solvents, but containing no crosslinked acrylic acid polymer in the inks. In this case, the ink has a Newton viscosity as in Comparative Example 1. In Comparative Example 5, an attempt was made to make the ink relatively low in viscosity and improve the writability, but it was not sufficient. Needless to say, no improvement in ink leakage was found, but no effect of the hydrophilic solvent (polyhydric alcohol) on strikethrough of handwriting was found. On the other hand, in Comparative Example 6, the ink was made relatively high in viscosity, and an attempt was made to improve the strikethrough of the handwriting by employing a hydrophilic solvent. However, the effect was poor at such a viscosity. Further, the writing performance and the ink leakage were not solved in the same manner as in Comparative Example 1 in the same manner as in Comparative Example 1. Comparative Example 7 contains an aromatic alcohol, a coloring material, and a crosslinked acrylic acid polymer in the ink, and does not contain a polyhydric alcohol. In this case, the crosslinked acrylic acid polymer could not be uniformly swelled and dispersed in the ink, and could not be evaluated as a ballpoint pen ink.

[0030]

The ink for a ballpoint pen of the present invention is capable of writing with a low writing pressure with a smooth writing feel that was not available in conventional ballpoint pens, has high ink retention in the pen body, does not cause ink leakage, and has a small paper surface. It has an excellent writing effect that does not cause penetrating of handwriting.

Claims (13)

(57) [Claims] 1. A non-water-soluble polar solvent comprising (A) an aromatic alcohol and / or an aliphatic glycol phenyl ether, a polyhydric alcohol, (B) a coloring material, and (C) a crosslinked acrylic acid polymer. , (D) a triethanolamine and a water-insoluble organic amine, a shear rate of 400 sec.
An oil-based ballpoint pen ink having a viscosity at c- ¹ of 200 to 3000 mPas and a shear thinning index of 0.30 to 0.85. 2. The composition according to claim 1, wherein the water-insoluble polar solvent of the component (A) is 20 to 50% by weight of an aromatic alcohol and / or an aliphatic glycol phenyl ether based on the total weight of the ink.
The oil-based ballpoint pen ink according to claim 1, comprising 20% by weight to 50% by weight of a polyhydric alcohol. 3. The color material is 3% by weight to 3% by weight based on the total amount of the ink.
The oil-based ballpoint pen ink according to claim 1, which is 0% by weight. 4. The oil-based ballpoint pen ink according to claim 1, wherein the coloring material is an oil-soluble dye or a polyhydric alcohol-soluble water-soluble dye. 5. The ink according to claim 1, wherein the crosslinked acrylic acid polymer is incorporated in an amount of 0.3 to 2.0% by weight based on the whole ink.
5. The ink for a ball-point pen according to any one of the above items 4 to 4. 6. A water-insoluble organic amine is added in an amount of 0.5 to 5.0% by weight based on the whole ink, and triethanolamine is added in an amount of 0.5 to 4.0% by weight based on the whole ink. The oil-based ink for a ball-point pen according to any one of claims 1 to 5, which is blended. 7. The oil-based ink for a ball-point pen according to claim 1, further comprising a spinnability imparting agent. 8. The oil-based ballpoint pen ink according to claim 7, wherein the spinnability imparting agent is incorporated in an amount of 0.1% by weight to 1.5% by weight. 9. The oil-based ballpoint pen ink according to claim 1, wherein a rust preventive lubricant soluble in polyhydric alcohol and a bactericide soluble in polyhydric alcohol are blended. 10. A rust preventive lubricant soluble in polyhydric alcohol is 0.2% by weight to 3.0% by weight, and a bactericide soluble in polyhydric alcohol is 0.1% by weight to 1.0% by weight. The oil-based ink for a ball-point pen according to claim 9, wherein the ink is blended in an amount of 0.1%. 11. The method according to claim 1, wherein one or more fatty acids selected from lauric acid, oleic acid, ricinoleic acid, stearic acid and soybean oil fatty acid are blended as the lubricity improver. The described oil-based ink for ballpoint pens. 12. Fatty acid in an amount of 0.5% to 5.0% by weight.
The oil-based ink for a ball-point pen according to claim 11, which is blended. 13. A water-insoluble thickener comprising 0.1% by weight to 10% by weight.
The oil-based ballpoint pen ink according to any one of claims 1 to 12, which is blended by weight.