JPH08134393A - Oily black ink composition for ball-point pen - Google Patents

Abstract

PURPOSE: To obtain a low-toxic oily black ink composition excellent in light resistance and writing smoothness, deep in the color after written and excellent in stability over time, by using, as colorant, C.I. Solvent Black 7 and a basic dye-based salt-forming dye. CONSTITUTION: This ink composition having the above-mentioned advantages is obtained by incorporating a solvent such as phenyl cellosolve with a colorant made up of 5-40wt.% of C.I. Solvent Black and 1-10wt. of a salt-forming dye composed of a basic dye such as Basic Red 1 as the matrix and an acid dye such as Acid Yellow 23 or Acid Yellow 42 or an organic acid such as aliphatic carboxylic acid, aromatic carboxylic acid, aliphatic sulfonic acid or aromatic sulfonic acid followed by addition of a resin such as ketone resin and then agitating the blend in an oil bath at 60 deg.C to effect homogeneous dissolution.

Description

Detailed Description of the Invention

[0001]

The present invention is excellent in light resistance and writability,
The present invention relates to a low toxicity ink composition for oil-based ballpoint pens, which has a strong handwriting color and excellent stability over time.

[0002]

2. Description of the Related Art Conventionally, various studies and developments have been made on a black ink composition for a ballpoint pen, which is suitable for practical use and has good handwriting fastness, particularly good light resistance. Black inks for pigment-based oil-based ballpoint pens, which mainly consist of pigments, are generally well known, but this pigment-based oil-based ink has difficulty in dispersibility of the pigments, and pigment particles cause problems such as sedimentation over time. In particular, when used for a ballpoint pen, there is a large tendency that the ink flow passage is clogged and the ink flowability is hindered.

Dye-based oil-based inks for ball-point pens containing a general dye as a main component have the drawback that the dye chemically decomposes or reacts in terms of light resistance, fastness of handwriting, stability over time, and the like. In order to improve that point, especially in terms of handwriting fastness and light resistance, JP-B-6
As described in JP-A 2-9271, there has been proposed an oil-based ballpoint pen ink in which a chromium-containing dye which is a chromium complex salt of an acid dye is used alone or in combination. However, since the chromium-containing dye is a complex salt of an acid dye and chromium, the safety of heavy metals such as chromium has become a problem in recent years, and the development of black ink containing no heavy metals has been desired.

[0004] On the other hand, C.I. I. Solvent Black 7 so-called Nigrosine dye is known. However, C.I. I. Solvent Black 7 The so-called Nigrosine dye is originally a bluish black, and when trying to approach dark black alone, the amount must be increased, and as a result, the dye associates with time and the ink viscosity increases. It has been found that when the ballpoint pen is used by being filled with it, the writing tends to become defective over time, that is, the ejection of the ink from the pen tip becomes poor, and the handwriting becomes faint, which makes writing extremely impossible.

In addition, C.I. I. There is also a proposal to use Solvent Black 7 and a complementary color dye. For example, JP-A-62-7
No. 775 is proposed, but since a basic dye is combined as a complementary color dye, the basic dye is C.I. I. Influenced by active hydrogen of Solvent Black 7 over time,
Dye insolubilization and precipitation occurred, and there was a problem in the temporal stability of the ink. Therefore, an object of the present invention is to provide a dye-based black ink composition for oil-based ballpoint pens that solves the above problems.

[0006]

The present inventor has conducted various studies on dyes suitable for black ink for oil-based ballpoint pens, and as a result, C.I. I. Solvent Black 7
When a salt-forming dye having a basic dye as a base is used in combination, C.I. I.
Solving the negative effects of using Solvent Black 7 alone,
It was found that a satisfactory oil-based ink composition for a ballpoint pen was obtained, and the present invention was completed.

That is, the present invention relates to "1. CI Solvent Black 7 as a colorant,
A black ink composition for oil-based ballpoint pens, which comprises using a salt-forming dye based on a basic dye. 2. The black ink composition for oil-based ballpoint pens according to claim 1, wherein the salt-forming dye based on the basic dye is a salt-forming dye of a basic dye and an acid dye. 3. The black ink composition for oil-based ballpoint pens according to claim 1, wherein the salt-forming dye based on the basic dye is a salt-forming dye of a basic dye and an organic acid. 4. The second salt-forming dye of a basic dye and an acid dye is a salt-forming dye of Basic Red 1 and Acid Yellow 23 or Basic Red 1 and Acid Yellow 42
A black ink composition for an oil-based ballpoint pen according to the item. 5. The salt forming dye of a basic dye and an organic acid is a salt forming dye of Basic Red 1 and at least one organic acid selected from an aliphatic carboxylic acid, an aromatic carboxylic acid, an aliphatic sulfonic acid and an aromatic sulfonic acid. The black ink composition for an oil-based ballpoint pen according to item 3. 6. C. I. Solvent Black 7 content 5-40
% By weight, and the amount of salt-forming dye based on the basic dye is 1
The black ink composition for oil-based ballpoint pens according to any one of items 1 to 5, which is 10% by weight. 7. 7. The black ink composition for oil-based ballpoint pens according to any one of items 1 to 6, wherein the salt-forming dye is a red dye. "
Is.

The present inventor has found that C.I. I. Research was conducted to eliminate the harmful effects of Solvent Black 7 used alone. As a result, when salt-forming dyes containing basic dyes as a base were used in combination, decomposition of dyes, insolubilization and precipitation of dyes due to reactions between dyes, etc. were eliminated. It has excellent stability over time and, in addition to the complementary color effect that makes the writing density darker and darker, C.I. I. It has been found that an increase in the amount of Solvent Black 7 is avoided and it becomes difficult to increase the viscosity.

The salt-forming dye based on the basic dye used in the present invention is a salt-forming dye of a basic dye and an acid dye, or a salt-forming dye of a basic dye and an organic acid. I. It is preferable because it does not react with Solvent Black 7 over time.

Salt-forming dyes having a basic dye as a base are C.I.
I. The reason why it does not react with Solvent Black 7 over time is that a salt-forming dye based on a basic dye reacts strongly with the cationic group of the basic dye, the acidic dye, and the anionic group of the organic acid to form a salt. Since it is formed, C.I. I. This is because the solvent black 7 is less likely to be affected by active hydrogen.

In addition, even if a basic dye and an acidic component such as an organic acid are separately added to the ink and blended to carry out salt formation,
Due to insufficient reaction, C.I. I. It is not preferable because the effect of active hydrogen of Solvent Black 7 is influenced with time and precipitation of dye occurs.

The present invention will be described in detail below.
C. I. The blending amount of Solvent Black 7 is 5 to 40% by weight in terms of handwriting light resistance and ink stability over time.
Is preferred. If it is less than this range, the light resistance of the handwriting becomes insufficient, and if it is more than this range, the viscosity of the ink tends to increase with time, which is not preferable.

The salt-forming dye based on the basic dye used in the present invention is originally a C.I. I. Since Solvent Black 7 is bluish black, the use of a red dye produces a better complementary color effect.

Examples of red salt-forming dyes of basic dyes and acid dyes include salt-forming dyes of Basic Red 1 and Ascided Yellow 23, salt-forming dyes of Basic Red 1 and Ascided Yellow 42, and the like. Can be mentioned.

Examples of red salt-forming dyes of basic dyes and organic acids include salt-forming dyes of Basic Red 1 and alkylbenzene sulfonic acid.

The amount of these salt-forming dyes is preferably 1 to 10% by weight from the viewpoint of the color tone of the handwriting. If it is less than this range, the bluishness is increased, and if it is more than this range, the reddishness is increased, which is not preferable.

C. I. The total amount of the colorant comprising Solvent Black 7 and a salt-forming dye having a basic dye as a base is preferably 10 to 50% by weight in terms of handwriting density. If it is less than this range, the handwriting density becomes lighter,
If it is too large, the ink viscosity tends to be too high, which is not preferable.

The black ink composition for oil-based ball-point pens of the present invention contains a resin and a solvent as main components in addition to the above-mentioned colorant, and optionally, a spinnability imparting agent, a lubricant and a rust preventive agent. , Various additives such as activators may be added.

The resin used in the present invention is blended for the purpose of adjusting viscosity and fixing the handwriting. Specific examples of these include ketone resins, rosin-based resins, polyvinylpyrrolidone, polyvinyl butyral and poly. Examples thereof include resins that are soluble in organic solvents used for inks such as vinyl acetate.

The blending amount of these resins cannot be determined unconditionally because it is appropriately adjusted depending on the target ink viscosity and the resin used, but it is preferably about 0.1 to 40% by weight. These resins may be used alone or in combination of two or more.

The solvent used in the present invention is preferably a solvent that dissolves the resin and dye used, such as phenyl cellosolve, phenyl carbitol, benzyl alcohol, propylene glycol, triethylene glycol, polyethylene glycol, 1,3-butanediol, 2-ethylhexanol and the like can be mentioned.

The blending amount of these solvents depends on the resin used,
The dye is dissolved and appropriately added in order to obtain a desired ink viscosity, so it cannot be determined unconditionally, but it is preferably about 5 to 80% by weight. These solvents can be used alone or in combination of two or more.

[0023]

EXAMPLES The present invention will be specifically described below based on Examples and Comparative Examples. % In each example represents weight%.

Example 1 Nigrosine EX 27.0% (CI Solvent Black 7: manufactured by Orient Chemical Co., Ltd.) Varifast Red 1320 3.0% (salt forming dye of Basic Red 1 and acid dye: Orient Chemical Co., Ltd. Hirac 111 (Ketone resin: Hitachi Chemical Co., Ltd.) 10.0% Oleic acid 5.0% Phenylcellosolve 55.0% The above compositions are mixed and mixed at 60 ° C. The ink for oil-based ball-point pens was prepared by stirring in an oil bath. When this ink was filled in a ballpoint pen of BP-S (trade name) specification manufactured by Pilot Co., Ltd. and a writing test and a stability test with time were performed as shown below, satisfactory results as shown in Table 1 were obtained. Obtained.

[0025]

[Table 1]

(Writing test) Blurring: In the writing test specified in JIS S-6039, the blurring state of the handwriting when writing was done until the end of the ink was visually judged. Color tone: The color tone of the handwriting was visually determined by the above writing test. Light resistance: Judged by the method specified in JIS S-6039. (Stability over time) After the ballpoint pen was left in a cap-off state in an environment of 50 ° C. and 100% RH for 2 months, a handwriting test and an ink microscopic observation were performed.

Example 2 Nigrosine EX (supra) 29.0% Varifast Red 1355 1.0% (salt-forming dye of Basic Red 1 and acid dye: manufactured by Orient Chemical Co., Ltd.) Hirac 111 (previously Out) 10.0% Oleic acid 5.0% Phenylcellosolve 55.0% The above components were prepared in the same manner as in Example 1, filled in a ballpoint pen having the same specifications as in Example 1, and subjected to the same test. By the way
Satisfactory results as shown in Table 1 were obtained.

Example 3 Nigrosine EX (supra) 20.0% Varifast Red 1360 10.0% (salt-forming dye of Basic Red 1 and organic acid: manufactured by Orient Chemical Co., Ltd.) Hirac 111 (previously Out) 10.0% Oleic acid 5.0% Phenylcellosolve 55.0% The above components were prepared in the same manner as in Example 1, filled in a ballpoint pen having the same specifications as in Example 1, and subjected to the same test. By the way
Satisfactory results as shown in Table 1 were obtained.

Example 4 Nigrosine EX (supra) 10.0% Varifast Violet 1701 20.0% (salt-forming dye of basic dye and acid dye: manufactured by Orient Chemical Co., Ltd.) Spyron Red C-GH 3 0.0% (added salt dye of Basic Red 1 and organic acid: Hodogaya Chemical Co., Ltd.) Hirac 111 (described above) 10.0% Oleic acid 5.0% Phenylcellosolve 40.0% Benzyl alcohol 12.0% The above components were prepared in the same manner as in Example 1, filled in a ballpoint pen having the same specifications as in Example 1, and subjected to the same test.
Satisfactory results as shown in Table 1 were obtained.

Comparative Example 1 Nigrosine EX (supra) 27.0% R06G-B 3.0% (basic dye / CI Basic Red 1: manufactured by Orient Chemical Co., Ltd.) Hirac 111 (supra) ) 10.0% Oleic acid 5.0% Phenylcellosolve 55.0% The above components were prepared in the same manner as in Example 1, filled in a ballpoint pen having the same specifications as in Example 1, and subjected to the same test. ,
The results shown in Table 1 were obtained, and the ink in the ballpoint pen tip was left to stand in an environment of 50 ° C. and 100% RH for 1 month, and the ink in the ballpoint pen tip was observed with a microscope.

Comparative Example 2 Nigrosine EX (supra) 3.0% Varifast Violet 1701 (supra) 30.0% Spiron Red C-GH (supra) 1.0% Hirac 111 (supra) 10.0 % Oleic acid 5.0% Phenylcellosolve 40.0% Benzyl alcohol 11.0% The above components were prepared in the same manner as in Example 1, filled in a ballpoint pen having the same specifications as in Example 1, and subjected to the same test. Where
The results shown in Table 1 were obtained, and the light resistance was insufficient.

[0032]

As is apparent from the above test results, the present invention has an oil-based property which has the light resistance, the writing property, the color strength of the handwriting, the stability over time, and the low toxicity due to its specific constitution. A black ink composition for a ballpoint pen can be obtained.

Claims (7)

[Claims] 1. A colorant such as C.I. I. A black ink composition for oil-based ballpoint pens, which comprises Solvent Black 7 and a salt-forming dye having a basic dye as a base material. 2. The black ink composition for an oil-based ballpoint pen according to claim 1, wherein the salt-forming dye based on the basic dye is a salt-forming dye of a basic dye and an acid dye. 3. The black ink composition for an oil-based ballpoint pen according to claim 1, wherein the salt-forming dye having a basic dye as a base is a salt-forming dye of a basic dye and an organic acid. 4. The oil-based ballpoint pen according to claim 2, wherein the salt-forming dye of a basic dye and an acid dye is a salt-forming dye of Basic Red 1 and Acid Yellow 23, or Basic Red 1 and Acid Yellow 42. Black ink composition. 5. A salt-forming dye of a basic dye and an organic acid comprises Basic Red 1 and at least one organic acid selected from aliphatic carboxylic acids, aromatic carboxylic acids, aliphatic sulfonic acids, and aromatic sulfonic acids. The black ink composition for an oil-based ball-point pen according to claim 3, which is the salt-forming dye. 6. C.I. I. The black ink for oil-based ballpoint pens according to any one of claims 1 to 5, wherein the blending amount of Solvent Black 7 is 5 to 40% by weight, and the blending amount of the salt-forming dye based on the basic dye is 1 to 10% by weight. Composition. 7. The black ink composition for oil-based ballpoint pens according to claim 1, wherein the salt-forming dye is a red dye.